Mechanism research on arsenic removal from arsenopyrite ore during a sintering process

NASA Astrophysics Data System (ADS)

Cheng, Ri-jin; Ni, Hong-wei; Zhang, Hua; Zhang, Xiao-kun; Bai, Si-cheng

2017-04-01

The mechanism of arsenic removal during a sintering process was investigated through experiments with a sintering pot and arsenic-bearing iron ore containing arsenopyrite; the corresponding chemical properties of the sinter were determined by inductively coupled plasma atomic emission spectrometry (ICP-AES), X-ray diffraction (XRD), and scanning electron microscopy (SEM) coupled with energy-dispersive X-ray spectroscopy (EDS). The experimental results revealed that the reaction of arsenic removal is mainly related to the oxygen atmosphere and temperature. During the sintering process, arsenic could be removed in the ignition layer, the sinter layer, and the combustion zone. A portion of FeAsS reacted with excess oxygen to generate FeAsO4, and the rest of the FeAsS reacted with oxygen to generate As2O3(g) and SO2(g). A portion of As2O3(g) mixed with Al2O3 or CaO, which resulted in the formation of arsenates such as AlAsO4 and Ca3(AsO4)2, leading to arsenic residues in sintering products. The FeAsS component in the blending ore was difficult to decompose in the preliminary heating zone, the dry zone, or the bottom layer because of the relatively low temperatures; however, As2O3(g) that originated from the high-temperature zone could react with metal oxides, resulting in the formation of arsenate residues.

Solidification/stabilization of chromite ore processing residue using alkali-activated composite cementitious materials.

PubMed

Huang, Xiao; Zhuang, RanLiang; Muhammad, Faheem; Yu, Lin; Shiau, YanChyuan; Li, Dongwei

2017-02-01

Chromite Ore Processing Residue (COPR) produced in chromium salt production process causes a great health and environmental risk with Cr(VI) leaching. The solidification/stabilization (S/S) of COPR using alkali-activated blast furnace slag (BFS) and fly ash (FA) based cementitious material was investigated in this study. The optimum percentage of BFS and FA for preparing the alkali-activated BFS-FA binder had been studied. COPR was used to replace the amount of BFS-FA or ordinary Portland cement (OPC) for the preparation of the cementitious materials, respectively. The immobilization effect of the alkali-activated BFS-FA binder on COPR was much better than that of OPC based cementitious material. The potential for reusing the final treatment product as a readily available construction material was evaluated. X-ray diffraction (XRD), Fourier transform infrared spectrometry (FTIR) and scanning electron microscope with energy dispersive spectrometer (SEM-EDS) analysis indicated that COPR had been effectively immobilized. The solidification mechanism is the combined effect of reduction, ion exchange, precipitation, adsorption and physical fixation in the alkali-activated composite cementitious material. Copyright © 2016 Elsevier Ltd. All rights reserved.

IN-SITU CR(VI) SOURCE AND PLUME TREATMENT USING A FERROUS IRON BASED REDUCTANT

EPA Science Inventory

A large volume of chromite ore processing residue (COPR) generated from ferrochrome production operations is present at the Macalloy Corporation Superfund site in Charleston, S.C. Groundwater hexavalent chromium (Cr(VI)) concentrations in the approximately 20 acre-foot COPR satu...

IN-SITU CR(VI) SOURCE AND PLUME TREATMENT USING A FERROUS IRON-BASED REDUCTANT

EPA Science Inventory

A large volume of chromite ore processing residue (COPR) generated from ferrochrome production operations is present at the Macalloy Corporation Superfund site in Charleston, S.C. Groundwater hexavalent chromium (Cr(VI)) concentrations in the approximately 20 acre-foot COPR sat...

Origin of Fe-Ti Oxide Mineralization in the Middle Paleoproterozoic Elet'ozero Syenite-Gabbro Intrusive Complex (Northern Karelia, Russia)

NASA Astrophysics Data System (ADS)

Sharkov, E. V.; Chistyakov, A. V.; Shchiptsov, V. V.; Bogina, M. M.; Frolov, P. V.

2018-03-01

Magmatic oxide mineralization widely developed in syenite-gabbro intrusive complexes is an important Fe and Ti resource. However, its origin is hotly debatable. Some researchers believe that the oxide ores were formed through precipitation of dense Ti-magnetite in an initial ferrogabbroic magma (Bai et al., 2012), whereas others consider them as a product of immiscible splitting of Fe-rich liquid during crystallization of Fe-Ti basaltic magma (Zhou et al., 2013). We consider this problem with a study of the Middle Paleoproterozoic (2086 ± 30 Ma) Elet'ozero Ti-bearing layered intrusive complex in northern Karelia (Baltic Shield). The first ore-bearing phase of the complex is mainly made up of diverse ferrogabbros, with subordinate clinopyroxenites and peridotites. Fe-Ti oxides (magnetite, Ti-magnetite, and ilmenite) usually account for 10-15 vol %, reaching 30-70% in ore varieties. The second intrusive phase is formed by alkaline and nepheline syenites. Petrographical, mineralogical, and geochemical data indicate that the first phase of the intrusion was derived from a moderately alkaline Fe-Ti basaltic melt, while the parental melt of the second phase was close in composition to alkaline trachyte. The orebodies comprise disseminated and massive ores. The disseminated Fe-Ti oxide ores make up lenses and layers conformable to general layering. Massive ores occur in subordinate amounts as layers and lenses, as well as cross-cutting veins. Elevated Nb and Ta contents in Fe-Ti oxides makes it possible to consider them complex ores. It is shown that the Fe-Ti oxide mineralization is related to the formation of a residual (Fe,Ti)-rich liquid, which lasted for the entire solidification history of the first intrusive phase. The liquid originated through multiple enrichment of Fe and Ti in the crystallization zone of the intrusion owing to the following processes: (1) precipitation of silicate minerals in the crystallization zone with a corresponding increase in the Fe and Ti contents in an interstitial melt; and (2) periodic accumulation of the residual melt in front of this zone. Unlike liquid immiscibility leading to melt splitting into two phases, this liquid dissolved the residual components of the melt. Correspondingly, such an Fe-rich liquid has unusual properties and requires further study.

Enrichment of Sc2O3 and TiO2 from bauxite ore residues.

PubMed

Deng, Bona; Li, Guanghui; Luo, Jun; Ye, Qing; Liu, Mingxia; Peng, Zhiwei; Jiang, Tao

2017-06-05

As a major byproduct generated in the alumina industry, bauxite ore residue is an important reserve of scandium and titanium. In this study, the feasibility and mechanism of enriching Sc 2 O 3 and TiO 2 from a non-magnetic material, which was obtained from carbothermal reductive roasting and magnetic separation of bauxite ore residue, were investigated based on a two-step (acidic and alkali) leaching process. It was revealed that approximately 78% SiO 2 and 30-40% of CaO, FeO and Al 2 O 3 were removed from a non-magnetic material with 0.0134wt.% Sc 2 O 3 and 7.64wt.% TiO 2 by phosphoric acidic leaching, while about 95% Al 2 O 3 and P 2 O 5 were further leached by subsequent sodium hydroxide leaching of the upper-stream leach residue. A Sc 2 O 3 -, TiO 2 - rich material containing 0.044wt.% Sc 2 O 3 and 25.5wt.% TiO 2 was obtained, the recovery and the enrichment factor of Sc 2 O 3 and TiO 2 were about 85% and 5, respectively. The enrichment of Sc 2 O 3 was attributed to higher pH (>3.3) of phosphoric acid solution than its dissolution pH 0 , and the enrichment of TiO 2 was mainly associated with the insoluble perovskite (CaTiO 3 ) in the acidic solution at ambient temperature. As Sc 2 O 3 and TiO 2 cannot be dissolved in the alkali solution, they were further enriched in the leach residue. Copyright © 2017 Elsevier B.V. All rights reserved.

Chemical and mineralogical characterization of chromite ore processing residue from two recent Indian disposal sites.

PubMed

Matern, Katrin; Kletti, Holger; Mansfeldt, Tim

2016-07-01

Chromite ore processing residue (COPR) is a hazardous waste. Nevertheless, deposition of COPR in uncontrolled surface landfills is still common practice in some countries. Whereas old (between at least 40 and 180 years) COPR from the temperate zone has been intensively investigated, information on COPR in other regions is restricted. Relatively young (<25 years) COPR samples obtained from two abandoned landfill sites in India were investigated by a modified total microwave digestion method, X-ray powder diffraction (XRPD), and scanning electron microscopy (SEM) in order to determine their chemical and mineralogical nature. By the use of microwave digestion with acid mixtures of HNO3, H3PO4, and HBF4 (5:3:2 vol), COPR was completely dissolved and element contents similar to those obtained by X-ray fluorescence were found. Total Cr contents of the two COPR accounted for 81 and 74 g kg(-1), of which 20 and 13% were present in the carcinogenic hexavalent form (CrVI). Apart from the common major mineral phases present in COPR reported earlier, a further Cr host mineral, grimaldiite [CrO(OH)], could be identified by XRPD and SEM. Additionally, well soluble Na2CrO4 was present. Improving the effectiveness of chromite ore processing and preventing the migration of Cr(VI) into water bodies are the main challenges when dealing with these COPR. Copyright © 2016 Elsevier Ltd. All rights reserved.

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 26 Internal Revenue 4 2013-04-01 2013-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 26 Internal Revenue 4 2012-04-01 2012-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

26 CFR 1.381(c)(18)-1 - Depletion on extraction of ores or minerals from the waste or residue of prior mining.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 26 Internal Revenue 4 2014-04-01 2014-04-01 false Depletion on extraction of ores or minerals from...) Insolvency Reorganizations § 1.381(c)(18)-1 Depletion on extraction of ores or minerals from the waste or... the applicability of section 613(c)(3) (relating to extraction of ores or minerals from the ground...

Natural radionuclide concentrations in processed materials from Thai mineral industries.

PubMed

Chanyotha, S; Kranrod, C; Chankow, N; Kritsananuwat, R; Sriploy, P; Pangza, K

2012-11-01

The naturally occurring radioactive materials (NORMs) distributed in products, by-products and waste produced from Thai mineral industries were investigated. Samples were analysed for radioactivity concentrations of two principal NORM isotopes: (226)Ra and (228)Ra. The enrichment of NORM was found to occur during the treatment process of some minerals. The highest activity of (226)Ra (7 × 10(7) Bq kg(-1)) was in the scale from tantalum processing. The radium concentration in the discarded by-product material from metal ore dressing was also enriched by 3-10 times. Phosphogypsum, a waste produced from the production of phosphate fertilisers, contained 700 times the level of (226)Ra concentration found in phosphate ore. Hence, these residues were also sources of exposure to workers and the public, which needed to be controlled.

Comprehensive recovery of gold and base-metal sulfide minerals from a low-grade refractory ore

NASA Astrophysics Data System (ADS)

Li, Wen-juan; Liu, Shuang; Song, Yong-sheng; Wen, Jian-kang; Zhou, Gui-ying; Chen, Yong

2016-12-01

The comprehensive recovery of small amounts of valuable minerals such as gold and base-metal sulfide minerals from a low-grade refractory ore was investigated. The following treatment strategy was applied to a sample of this ore: gold flotation-gold concentrate leaching-lead and zinc flotation from the gold concentrate leaching residue. Closed-circuit trials of gold flotation yielded a gold concentrate that assayed at 40.23 g·t-1 Au with a recovery of 86.25%. The gold concentrate leaching rate was 98.76%. Two variants of lead-zinc flotation from the residue—preferential flotation of lead and zinc and bulk flotation of lead and zinc—were tested using the middling processing method. Foam from the reflotation was returned to the lead rougher flotation or lead-zinc bulk flotation, whereas middlings from reflotation were discarded. Sulfur concentrate was a byproduct. The combined strategy of flotation, leaching, and flotation is recommended for the treatment of this kind of ore.

URANIUM RECOVERY PROCESS

DOEpatents

Kaufman, D.

1958-04-15

A process of recovering uranium from very low-grade ore residues is described. These low-grade uraniumcontaining hydroxide precipitates, which also contain hydrated silica and iron and aluminum hydroxides, are subjected to multiple leachings with aqueous solutions of sodium carbonate at a pH of at least 9. This leaching serves to selectively extract the uranium from the precipitate, but to leave the greater part of the silica, iron, and aluminum with the residue. The uranium is then separated from the leach liquor by the addition of an acid in sufficient amount to destroy the carbonate followed by the addition of ammonia to precipitate uranium as ammonium diuranate.

Pyrolysis Treatment of Chromite Ore Processing Residue by Biomass: Cellulose Pyrolysis and Cr(VI) Reduction Behavior.

PubMed

Zhang, Da-Lei; Zhang, Mei-Yi; Zhang, Chu-Hui; Sun, Ying-Jie; Sun, Xiao; Yuan, Xian-Zheng

2016-03-15

The pyrolysis treatment with biomass is a promising technology for the remediation of chromite-ore-processing residue (COPR). However, the mechanism of this process is still unclear. In this study, the behavior of pyrolysis reduction of Cr(VI) by cellulose, the main component of biomass, was elucidated. The results showed that the volatile fraction (VF) of cellulose, ie. gas and tar, was responsible for Cr(VI) reduction. All organic compounds, as well as CO and H2 in VF, potentially reduced Cr(VI). X-ray absorption near-edge structure (XANES) spectroscopy and extended X-ray absorption fine-structure (EXAFS) spectroscopy confirmed the reduction of Cr(VI) to Cr(III) and the formation of amorphous Cr2O3. The remnant Cr(VI) content in COPR can be reduced below the detection limit (2 mg/kg) by the reduction of COPR particle and extension of reaction time between VF and COPR. This study provided a deep insight on the co-pyrolysis of cellulose with Cr(VI) in COPR and an ideal approach by which to characterize and optimize the pyrolysis treatment for COPR by other organics.

Gold ores related to shear zones, West Santa Comba-Fervenza Area (Galicia, NW Spain): A mineralogical study

NASA Astrophysics Data System (ADS)

Castroviejo, R.

1990-12-01

Recent research has discovered high-grade Au ores in NNE-SSW trending shear zones in metamorphic proterozoic and palaeozoic terranes, some 40 km NW of Santiago de Compostela (NW Spain). The orebodies are bound to late-stage Hercynian structures, mainly due to brittle deformation, which are superimposed on earlier ductile shear zones, cutting through various catazonal lithologies, including ortho- and paragneisses, amphibolites, eclogites, and granites. Ore mineralogy, alteration, and ore textures define a frame whose main features are common to all prospects in the area. Main minerals are arsenopyrite and pyrite — accompanied by quartz, adularia, sericite, ± (tourmaline, chlorite, carbonates, graphite), as main gangue minerals -with subordinate amounts of boulangerite, bismuthinite, kobellite, jamesonite, chalcopyrite, marcasite, galena, sphalerite, rutile, titanite, scheelite, beryl, fluorite, and minor native gold, electrum, native bismuth, fahlore, pyrrhotite, mackinawite, etc., defining a meso-catathermal paragenesis. Detailed microscopic study allows the author to propose a general descriptive scheme of textural classification for this type of ore. Most of the ores fill open spaces or veins, seal cracks or cement breccias; disseminated ores with replacement features related to alteration (mainly silicification, sericitization, and adularization) are also observed. Intensive and repeated cataclasis is a common feature of many ores, suggesting successive events of brittle deformation, hydrothermal flow, and ore precipitation. Gold may be transported and accumulated in any of these events, but tends to be concentrated in later ones. The origin of the gold ores is explained in terms of hydrothermal discharge, associated with mainly brittle deformation and possibly related to granitic magmas, in the global tectonic frame of crustal evolution of West Galicia. The mineralogical and textural study suggests some criteria which will be of practical value for exploration and for ore processing. Ore grades can be improved by flotation of arsenopyrite. Non-conventional methods, such as pressure or bacterial leaching, may subsequently obtain a residue enriched in gold.

Optimization of staged bioleaching of low-grade chalcopyrite ore in the presence and absence of chloride in the irrigating lixiviant: ANFIS simulation.

PubMed

Vakylabad, Ali Behrad; Schaffie, Mahin; Naseri, Ali; Ranjbar, Mohammad; Manafi, Zahra

2016-07-01

In this investigation, copper was bioleached from a low-grade chalcopyrite ore using a chloride-containing lixiviant. In this regard, firstly, the composition of the bacterial culture media was designed to control the cost in commercial application. The bacterial culture used in this process was acclimated to the presence of chloride in the lixiviant. Practically speaking, the modified culture helped the bio-heap-leaching system operate in the chloridic media. Compared to the copper recovery from the low-grade chalcopyrite by bioleaching in the absence of chloride, bioleaching in the presence of chloride resulted in improved copper recovery. The composition of the lixiviant used in this study was a modification with respect to the basal salts in 9 K medium to optimize the leaching process. When leaching the ore in columns, 76.81 % Cu (based on solid residues of bioleaching operation) was recovered by staged leaching with lixiviant containing 34.22 mM NaCl. The quantitative findings were supported by SEM/EDS observations, X-ray elemental mapping, and mineralogical analysis of the ore before and after leaching. Finally, Adaptive neuro-fuzzy inference system (ANFIS) was used to simulate the operational parameters affecting the bioleaching operation in chloride-sulfate system.

The enhancing of Au-Ag-Te content in tellurium-bearing ore mineral by bio-oxidation-leaching

NASA Astrophysics Data System (ADS)

Kim, PyeongMan; Kim, HyunSoo; Myung, EunJi; Kim, YoonJung; Lee, YongBum; Park*, CheonYoung

2015-04-01

The purpose of this study is to enhance the content of valuable metals such as Au-Ag-Te in tellurium-bearing minerals by bio-oxidation-leaching. It was confirmed that pyrite, chalcopyrite, sphalerite and galena were produced together with tellurium-bearing minerals including hessite, sylvanite and tellurobismuthite from ore minerals and concentrates through microscopic observation and SEM/EDS analysis. In a bio-oxidation-leaching experiment, with regard to Au, Ag, Te, Cu and Fe, the changes in the amount of leaching and the content of leaching residues were compared and analyzed with each other depending on the adaptation of an indigenous microbe identified as Acidithiobacillus ferrooxidans. As a result of the experiment, the Au-Ag-Te content in tellurium-bearing ore mineral was enhanced in the order of physical oxidation leaching, physical/non-adaptive bio-oxidation-leaching and physical/adaptive biological leaching. It suggests that the bio-oxidation-leaching using microbes adapted in tellurium-bearing ore mineral can be used as a pre-treatment and a main process in a recovery process of valuable metals. "This research was supported by Basic Science Research Program through the National Research Foundation of Korea(NRF) funded by the Ministry of Education(NRF-2013R1A1A2004898)"

Application of Sequential Extractions and X-ray Absorption Spectroscopy to Determine the Speciation of Chromium in Northern New Jersey Marsh Soils Developed in Chromite ore Processing Residue (COPR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Elzinga, E.; Cirmo, A

2010-01-01

The Cr speciation in marsh soils developed in weathering chromite ore processing residue (COPR) was characterized using sequential extractions and synchrotron microbeam and bulk X-ray absorption spectroscopic (XAS) analyses. The sequential extractions suggested substantial Cr associated with reducible and oxidizable soil components, and significant non-extractable residual Cr. Notable differences in Cr speciation estimates from three extraction schemes underscore the operationally defined nature of Cr speciation provided by these methods. Micro X-ray fluorescence maps and {mu}-XAS data indicated the presence of {micro}m-sized chromite particles scattered throughout the weathered COPR matrix. These particles derive from the original COPR material, and have relativelymore » high resistance towards weathering, and therefore persist even after prolonged leaching. Bulk XAS data further indicated Cr(III) incorporated in Fe(OH){sub 3}, and Cr(III) associated with organic matter. The low Cr contents of the weathered material (200-850 ppm) compared to unweathered COPR (20,000-60,000 ppm) point to substantial Cr leaching during COPR weathering, with partial repartitioning of released Cr into secondary Fe(OH){sub 3} phases and organics. The effects of anoxia on Cr speciation, and the potential of active COPR weathering releasing Cr(VI) deeper in the profile require further study.« less

Leach of the weathering crust elution-deposited rare earth ore for low environmental pollution with a combination of (NH4)2SO4 and EDTA.

PubMed

Tang, Jie; Qiao, Jiyang; Xue, Qiang; Liu, Fei; Chen, Honghan; Zhang, Guochen

2018-05-01

High concentration of ammonium sulfate, a typical leaching agent, was often used in the mining process of the weathering crust elution-deposited rare earth ore. After mining, a lot of ammonia nitrogen and labile heavy metal fractions were residual in tailings, which may result in a huge potential risk to the environment. In this study, in order to achieve the maximum extraction of rare earth elements and reduce the labile heavy metal, extraction effect and fraction changes of lanthanum (La) and lead (Pb) in the weathering crust elution-deposited rare earth ore were studied by using a compound agent of (NH 4 ) 2 SO 4 -EDTA. The extraction efficiency of La was more than 90% by using 0.2% (NH 4 ) 2 SO 4 -0.005 M EDTA, which was almost same with that by using 2.0% (NH 4 ) 2 SO 4 solution. In contrast, the extraction efficiency of Pb was 62.3% when use 0.2% (NH 4 ) 2 SO 4 -0.005 M EDTA, which is much higher than that (16.16%) achieved by using 2.0% (NH 4 ) 2 SO 4 solution. The released Pb fractions were mainly acid extractable and reducible fractions, and the content of reducible fraction being leached accounted for 70.45% of the total reducible fraction. Therefore, the use of 0.2% (NH 4 ) 2 SO 4 -0.005 M EDTA can not only reduce the amount of (NH 4 ) 2 SO 4 , but also decrease the labile heavy metal residues in soil, which provides a new way for efficient La extraction with effective preventing and controlling environmental pollution in the process of mining the weathering crust elution-deposited rare earth ore. Copyright © 2018 Elsevier Ltd. All rights reserved.

Characterisation and Processing of Some Iron Ores of India

NASA Astrophysics Data System (ADS)

Krishna, S. J. G.; Patil, M. R.; Rudrappa, C.; Kumar, S. P.; Ravi, B. P.

2013-10-01

Lack of process characterization data of the ores based on the granulometry, texture, mineralogy, physical, chemical, properties, merits and limitations of process, market and local conditions may mislead the mineral processing entrepreneur. The proper implementation of process characterization and geotechnical map data will result in optimized sustainable utilization of resource by processing. A few case studies of process characterization of some Indian iron ores are dealt with. The tentative ascending order of process refractoriness of iron ores is massive hematite/magnetite < marine black iron oxide sands < laminated soft friable siliceous ore fines < massive banded magnetite quartzite < laminated soft friable clayey aluminous ore fines < massive banded hematite quartzite/jasper < massive clayey hydrated iron oxide ore < manganese bearing iron ores massive < Ti-V bearing magnetite magmatic ore < ferruginous cherty quartzite. Based on diagnostic process characterization, the ores have been classified and generic process have been adopted for some Indian iron ores.

A greener approach for resource recycling: Manganese bioleaching.

PubMed

Ghosh, S; Mohanty, S; Akcil, A; Sukla, L B; Das, A P

2016-07-01

In view of unremitting diminution of mineral resources, rising energy economics along with increasing global consumption of Manganese (Mn), development of environment friendly technologies for tapping alternate sources of Mn has gained importance lately. Mn recovery from mining residues using conventional approaches is extremely expensive due to high capital and energy costs involved. However lean grade ores present in millions of tons awaits the development of competent and cost effective extractive process. Mn recovery by biomining with diverse microbes is thereby recommended as a superior and green alternative to the current pyro metallurgical techniques. The synergistic effects of different factors are known to influence microbial leaching of mineral ores which includes microbiological, mineralogical, physicochemical and process parameters. Bacterial bioleaching is mostly due to enzymatic influence, however fungal bioleaching is non enzymatic. Genomic studies on microbial diversity and an insight of its metabolic pathways provides unique dimension to the mechanism of biomining microorganisms. The extraction of Mn has a massive future prospective and will play a remarkable role in altering the situation of ever-decreasing grades of ore. This review aims to encompass the different aspects of Mn bioleaching, the plethora of organisms involved, the mechanisms driving the process and the recent trends and future prospects of this green technology. Copyright © 2016 Elsevier Ltd. All rights reserved.

Wetland-based passive treatment systems for gold ore processing effluents containing residual cyanide, metals and nitrogen species.

PubMed

Alvarez, R; Ordóñez, A; Loredo, J; Younger, P L

2013-10-01

Gold extraction operations generate a variety of wastes requiring responsible disposal in compliance with current environmental regulations. During recent decades, increased emphasis has been placed on effluent control and treatment, in order to avoid the threat to the environment posed by toxic constituents. In many modern gold mining and ore processing operations, cyanide species are of most immediate concern. Given that natural degradation processes are known to reduce the toxicity of cyanide over time, trials have been made at laboratory and field scales into the feasibility of using wetland-based passive systems as low-cost and environmentally friendly methods for long-term treatment of leachates from closed gold mine tailing disposal facilities. Laboratory experiments on discrete aerobic and anaerobic treatment units supported the development of design parameters for the construction of a field-scale passive system at a gold mine site in northern Spain. An in situ pilot-scale wetland treatment system was designed, constructed and monitored over a nine-month period. Overall, the results suggest that compost-based constructed wetlands are capable of detoxifying cyanidation effluents, removing about 21.6% of dissolved cyanide and 98% of Cu, as well as nitrite and nitrate. Wetland-based passive systems can therefore be considered as a viable technology for removal of residual concentrations of cyanide from leachates emanating from closed gold mine tailing disposal facilities.

Geodynamic and climate controls in the formation of Mio-Pliocene world-class oxidized cobalt and manganese ores in the Katanga province, DR Congo

NASA Astrophysics Data System (ADS)

Decrée, Sophie; Deloule, Étienne; Ruffet, Gilles; Dewaele, Stijn; Mees, Florias; Marignac, Christian; Yans, Johan; de Putter, Thierry

2010-10-01

The Katanga province, Democratic Republic of Congo, hosts world-class cobalt deposits accounting for ~50% of the world reserves. They originated from sediment-hosted stratiform copper and cobalt sulfide deposits within Neoproterozoic metasedimentary rocks. Heterogenite, the main oxidized cobalt mineral, is concentrated as “cobalt caps” along the top of silicified dolomite inselbergs. The supergene cobalt enrichment process is part of a regional process of residual ore formation that also forms world-class “manganese cap” deposits in western Katanga, i.e., the “black earths” that are exploited by both industrial and artisanal mining. Here, we provide constraints on the genesis and the timing of these deposits. Ar-Ar analyses of oxidized Mn ore and in situ U-Pb SIMS measurements of heterogenite yield Mio-Pliocene ages. The Ar-Ar ages suggest a multi-phase process, starting in the Late Miocene (10-5 Ma), when the metal-rich substratum was exposed to the action of meteoric fluids, due to major regional uplift. Further oxidation took place in the Pliocene (3.7-2.3 Ma) and formed most of the observed deposits under humid conditions: Co- and Mn-caps on metal-rich substrata, and coeval Fe laterites on barren areas. These deposits formed prior to the regional shift toward more arid conditions in Central Africa. Arid conditions still prevailed during the Quaternary and resulted in erosion and valley incision, which dismantled the metal-bearing caps and led to ore accumulation in valleys and along foot slopes.

Applications of bauxite residue: A mini-review.

PubMed

Verma, Ajay S; Suri, Narendra M; Kant, Suman

2017-10-01

Bauxite residue is the waste generated during alumina production by Bayer's process. The amount of bauxite residue (40-50 wt%) generated depends on the quality of bauxite ore used for the processing. High alkalinity and high caustic content in bauxite residue causes environmental risk for fertile soil and ground water contamination. The caustic (NaOH) content in bauxite residue leads to human health risks, like dermal problems and irritation to eyes. Moreover, disposal of bauxite residue requires a large area; such problems can only be minimised by utilising bauxite residue effectively. For two decades, bauxite residue has been used as a binder in cement industries and filler/reinforcement for composite materials in the automobile industry. Valuable metals and oxides, like alumina (Al 2 O 3 ), titanium oxide (TiO 2 ) and iron oxide Fe 2 O 3 , were extracted from bauxite residue to reduce waste. Bauxite residue was utilised in construction and structure industries to make geopolymers. It was also used in the making of glass-ceramics and a coating material. Recently bauxite residue has been utilised to extract rare earth elements like scandium (Sc), yttrium (Y), lanthanum (La), cerium (Ce), neodymium (Nd) and dysprosium (Dy). In this review article, the mineralogical characteristics of bauxite residue are summarised and current progresses on utilisation of bauxite residue in different fields of science and engineering are presented in detail.

The possible role of thiosulfate in the precipitation of 34S-rich barite in some Mississippi Valley-type deposits

USGS Publications Warehouse

Spirakis, C.S.

1991-01-01

The precipitation of extremely 34S-rich barite in the late stage of mineralization in the Mississippi Valleytype deposits of the Illinois-Kentucky district (U.S.A.) may be explained by reactions involving thiosulfate (S2O3=). Inorganic processes are known to concentrate 34S in the sulfonate site of thiosulfate and 32S in the sulfate site. In the mineralizing solution, these inorganic processes may have fractionated sulfur between the two sites by about 40 per mil. At the low temperatures of the late barite stage of mineralization, bacteria are known to metabolize thiosulfate by various reactions. In one of these, dissimilatory reduction, hydrogen sulfide and sulfite are produced. Isotopically light sulfite is preferentially reduced to sulfide by bacteria to leave a residual sulfite enriched in 34S. Part of the residual sulfite may be oxidized to form isotopically heavy sulfate; part may recombine with hydrogen sulfide to form thiosulfate. The recombination also enriches the sulfonate site in 34S and the sulfane site in 32S. Recycling the newly formed thiosulfate through the above steps further enriches sulfite and sulfate from oxidation of sulfite in 34S. During genesis of the ores, the aggregate effect of these reactions may have been the precipitation of extremely 34S-rich barite. The sequence of reactions suggested above requires the presence of organic matter. Previously proposed reactions to account for the precipitation of sulfide minerals and fluorite and for the carbonate paragenesis also require the presence of organic matter. Thus, organic matter in the host rocks may cause the various ore-zone reactions and account for the localization of the ores. ?? 1991 Springer-Verlag.

Pilot scale treatment of chromite ore processing residue using sodium sulfide in single reduction and coupled reduction/stabilization processes.

PubMed

Velasco, Antonio; Ramírez, Martha; Hernández, Sergio; Schmidt, Winfried; Revah, Sergio

2012-03-15

Single Cr(VI) reduction and coupled reduction/stabilization (R/S) processes were evaluated at pilot scale to determine their effectiveness to treat chromite ore processing residue (COPR). Sodium sulfide was used as the reducing agent and cement, gypsum and lime were tested as the stabilizing agents. The pilot experiments were performed in a helical ribbon blender mixer with batches of 250 kg of COPR and mixing time up to 30 min. Na2S/Cr(VI) mass ratios of 4.6, 5.7 and 6.8 were evaluated in the single reduction process to treat COPR with Cr(VI) concentration of ≈4.2 g/kg. The R/S process was tested with a Na2S/Cr(VI) mass ratio of 5.7 and including stabilizing agents not exceeding 5% (w/w(COPR)), to treat COPR with a Cr(VI) content of ≈5.1g/kg. The single reduction process with a ratio of 6.8, reached Cr(VI) reduction efficiencies up to 97.6% in the first days, however these values decreased to around 93% after 380 days of storage. At this point the total Cr level was around 12.5 mg/L. Cr(VI) removal efficiencies exceeding 96.5% were reached and maintained during 380 days when the coupled R/S process was evaluated. Total Cr levels lower than 5 mg/l were attained at the initials days in all R/S batch tested, however after 380 days, concentrations below the regulatory limit were only found with gypsum (2%) as single agent and with a blend of cement (4%) and lime (1%). These results indicated that the coupled R/S process is an excellent alternative to stabilize COPR. Copyright © 2011 Elsevier B.V. All rights reserved.

Investigation of mine and industry dumps in the FRG in relation to a possible release of natural radioactive elements.

PubMed

Schmitz, J

1985-10-01

More than 350 dumps of mines and industries in two federal states of the FRG were recorded, measured radiometrically, evaluated, and some of them sampled. Most of the mine dumps belonged to old and smaller residues from lead/zinc and iron ore mining, while the largest depositions contain tailings of modern ore beneficiation or flyash disposal. All mine dumps from uranium exploration in Baden-Württemberg and Bavaria were investigated. The highest doses, up to 100 mSv/a, were found on the piles of the uranium exploration. These depositions, which are supervised and licensed, are followed, in terms of surface dose, by the old uncontrolled mine dumps of silver/cobalt mining with doses up to 20 mSv/a. The numerous porphyry and granite quarries show doses between 1 and 2 mSv/a, as do flyash and slag dumps. The lowest doses were found on the dumps of the hydrothermal Pb/Zn and iron ore deposits, while the slag piles of iron ore processing showed higher thorium values. Assays for Ra-226 and Pb-210 of the materials deposited confirmed the radiometric results. Analyses of seepage waters and gallery waters showed only very few values exceeding the derived drinking water concentrations.

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2012 CFR

2012-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2014 CFR

2014-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2011 CFR

2011-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

10 CFR 40.67 - Requirement for advance notice for importation of natural uranium from countries that are not...

Code of Federal Regulations, 2013 CFR

2013-01-01

... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material... uranium from countries that are not party to the Convention on the Physical Protection of Nuclear Material. (a) Each licensee authorized to import natural uranium, other than in the form of ore or ore residue...

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012.

PubMed

Kaufman, John A; Brown, Mary Jean; Umar-Tsafe, Nasir T; Adbullahi, Muhammad Bashir; Getso, Kabiru I; Kaita, Ibrahim M; Sule, Binta Bako; Ba'aba, Ahmed; Davis, Lora; Nguku, Patrick M; Sani-Gwarzo, Nasir

2016-09-01

In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child's age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children's BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Obtained. The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. The authors declare no competing financial interests.

Uranium deposits at Shinarump Mesa and some adjacent areas in the Temple Mountain district, Emery County, Utah

USGS Publications Warehouse

Wyant, Donald G.

1953-01-01

Deposits of uraniferous hydrocarbons are associated with carnotite in the Shinarump conglomerate of Triassic age at Shinarump Mesa and adjacent areas of the Temple Mountain district in the San Rafael Swell of Emery County, Utah. The irregular ore bodies of carnotite-bearing sandstone are genetically related to lenticular uraniferous ore bodies containing disseminated asphaltitic and humic hydrocarbon in permeable sandstones and were localized indirectly by sedimentary controls. Nearly non-uraniferous bitumen commonly permeates the sandstones in the Shinarump conglomerate and the underlying Moekopi formation in the area. The ore deposits at Temple Mountain have been altered locally by hydrothermal solutions, and in other deposits throughout the area carnotite has been transported by ground and surface water. Uraniferous asphaltite is thought to be the non-volatile residue of an original weakly uraniferous crude oil that migrated into the San Rafael anticline; the ore metals concentrated in the asphaltite as the oil was devolatilized and polymerized. Carnotite is thought to have formed from the asphaltite by ground water leaching. It is concluded that additional study of the genesis of the asphaltitic uranium ores in the San Rafael Swell, of the processes by which the hydrocarbons interact and are modified (such as heat, polymerization, and hydrogenation under the influence of alpha-ray bombardment), of petroleum source beds, and of volcanic intrusive rocks of Tertiary age are of fundamental importance in the continuing study of the uranium deposits on the Colorado Plateau.

Multi-Criteria selection of technology for processing ore raw materials

NASA Astrophysics Data System (ADS)

Gorbatova, E. A.; Emelianenko, E. A.; Zaretckii, M. V.

2017-10-01

The development of Computer-Aided Process Planning (CAPP) for the Ore Beneficiation process is considered. The set of parameters to define the quality of the Ore Beneficiation process is identified. The ontological model of CAPP for the Ore Beneficiation process is described. The hybrid choice method of the most appropriate variant of the Ore Beneficiation process based on the Logical Conclusion Rules and the Fuzzy Multi-Criteria Decision Making (MCDM) approach is proposed.

Developments in the Disposal of Residue from the Alumina Refining Industry

NASA Astrophysics Data System (ADS)

Cooling, D. J.

The disposal of residue forms an integral part of the alumina refining process. The refining of Western Australia bauxite, which is low grade ore by world standards, results in 2 dry tonnes of residue for every 1 tonne of alumina produced. The disposal of this residue contributes a significant proportion of the overall cost of producing alumina. The residue is also highly alkaline, and, if not contained in sealed impoundment areas, can impact on the local environment. It has been these two considerations, the cost of disposal and the potential impact of disposal on the environment, which have been the main driving forces behind changes to the way residue is stored. This paper traces the various residue disposal techniques adopted by Alcoa of Australia Limited from containment in large settling ponds, to splitting the coarse and fine fractions for separate disposal, to the storage of the fine mud fraction in base drained ponds, to the more recent pre-thickening of the fine mud fraction for disposal in solar drying ponds. The reasons for change and the problems encountered are reviewed, and possible future developments are discussed.

REE Mineralization in Kiruna-type Magnetite-Apatite Ore Deposits: Magmatism and Metasomatism

NASA Astrophysics Data System (ADS)

Harlov, D. E.

2015-12-01

Magnetite-apatite ore bodies of the Kiruna type occur worldwide and are generally associated with volcanic rocks or volcanism. They also show strong evidence of extensive metasomatism over a wide P-T range. Notable examples include the Kiirunavaara ore body, northern Sweden (Harlov et al., 2002, Chem. Geol., 191, 47-72); the Grängesberg ore body, central Sweden (Jonsson et al., 2010, NGF abstracts, vol 1, 88-89); the Mineville ore body, Adirondacks, New York, USA (McKeown and Klemc, 1956, U.S. Geol Sur Bull (1956), pp. 9-23); the Pea Ridge ore body, SE Missouri, USA (Kerr, 1998, MS Thesis, Univ. Windsor, Windsor, Ontario, Canada 113 pp); the Jurassic Marcona ore body in south-central Peru (Chen et al., 2010, Econ Geol, 105, 1441-1456); and a collection of ore bodies from the Bafq Region, central Iran (Daliran et al., 2010, Geol. Assoc. Canada, Short Course Notes, v. 20, p.147-159). In these ore bodies, low Th and U monazite, xenotime, allanite, REE carbonates, and/or REE fluorides are commonly associated with the apatite as inclusions, rim grains, or as independent grains in the surrounding mineral matrix. High contrast BSE imaging, coupled with EMPA and LA-ICPMS, indicates that the apatite has experienced fluid-induced alteration in the form of (Y+REE) + Na + Si + Cl depletion implying that it served as the source for the (Y+REE) (e.g. Kiirunavaara, northern Sweden; Harlov et al., 2002). Formation of monazite and xenotime associated with fluorapatite, as inclusions or rim grains, has experimentally been demonstrated to originate from the fluorapatite as the result of fluid-aided, coupled dissolution-reprecipitation processes (Harlov et al., 2005, Contrib. Mineral. Petrol. 150, 268-286). This is explains the low Th and U content of the monazite and xenotime. Fluid sources could range from 700-900 °C, residual, acidic (HCl, H2HSO4) grain boundary fluids, remaining after the last stages of ore body crystallization, to later stage, cooler (< 600 °C) (H2O-CO2-(Na,K)Cl) fluids originating in the surrounding country rock or as fluids associated with metamorphic events such as regional albitization or actinolization. The abundance of (Y+REE)-bearing minerals in these deposits suggests that in addition to being mined for their Fe ore, they could also be economically mined for (Y+REE) as well.

10 CFR 40.23 - General license for carriers of transient shipments of natural uranium other than in the form of...

Code of Federal Regulations, 2010 CFR

2010-01-01

... 10 Energy 1 2010-01-01 2010-01-01 false General license for carriers of transient shipments of natural uranium other than in the form of ore or ore residue. 40.23 Section 40.23 Energy NUCLEAR REGULATORY COMMISSION DOMESTIC LICENSING OF SOURCE MATERIAL General Licenses § 40.23 General license for...

Prevalence and Risk Factors of Elevated Blood Lead in Children in Gold Ore Processing Communities, Zamfara, Nigeria, 2012

PubMed Central

Kaufman, John A.; Brown, Mary Jean; Umar-Tsafe, Nasir T.; Adbullahi, Muhammad Bashir; Getso, Kabiru I.; Kaita, Ibrahim M.; Sule, Binta Bako; Ba’aba, Ahmed; Davis, Lora; Nguku, Patrick M.; Sani-Gwarzo, Nasir

2018-01-01

Background In March 2010, Medecins Sans Frontieres/Doctors Without Borders detected an outbreak of acute lead poisoning in Zamfara State, northwestern Nigeria, linked to low-technology gold ore processing. The outbreak killed more than 400 children ≤5 years of age in the first half of 2010 and has left more than 2,000 children with permanent disabilities. Objectives The aims of this study were to estimate the statewide prevalence of children ≤5 years old with elevated blood lead levels (BLLs) in gold ore processing and non-ore-processing communities, and to identify factors associated with elevated blood lead levels in children. Methods A representative, population-based study of ore processing and non-ore-processing villages was conducted throughout Zamfara in 2012. Blood samples from children, outdoor soil samples, indoor dust samples, and survey data on ore processing activities and other lead sources were collected from 383 children ≤5 years old in 383 family compounds across 56 villages. Results 17.2% of compounds reported that at least one member had processed ore in the preceding 12 months (95% confidence intervals (CI): 9.7, 24.7). The prevalence of BLLs ≥10 µg/dL in children ≤5 years old was 38.2% (95% CI: 26.5, 51.4) in compounds with members who processed ore and 22.3% (95% CI: 17.8, 27.7) in compounds where no one processed ore. Ore processing activities were associated with higher lead concentrations in soil, dust, and blood samples. Other factors associated with elevated BLL were a child’s age and sex, breastfeeding, drinking water from a piped tap, and exposure to eye cosmetics. Conclusions Childhood lead poisoning is widespread in Zamfara State in both ore processing and non-ore-processing settings, although it is more prevalent in ore processing areas. Although most children’s BLLs were below the recommended level for chelation therapy, environmental remediation and use of safer ore processing practices are needed to prevent further exposures. Patient consent Obtained Ethics approval The study protocol was approved by the US Centers for Disease Control Institutional Review Board-A and the National Health Research Ethics Committee of Nigeria. Competing Interests The authors declare no competing financial interests. PMID:29416933

Assessment and evaluation of engineering options at a low-level radioactive waste storage site

NASA Astrophysics Data System (ADS)

Kanehiro, B. Y.; Guvanasen, V.

1982-09-01

Solutions to hydrologic and geotechnical problems associated with existing disposal sites were sought and the efficiency of engineering options that were proposed to improve the integrity of such sites were evaluated. The Weldon Spring site is generally like other low-level nuclear waste sites, except that the wastes are primarily in the form of residues and contaminated rubble from the processing of uranium and thorium ores rather than industrial isotopes or mill tailings.

Pyrolysis of chromium rich tanning industrial wastes and utilization of carbonized wastes in metallurgical process.

PubMed

Tôrres Filho, Artur; Lange, Liséte Celina; de Melo, Gilberto Caldeira Bandeira; Praes, Gustavo Eduardo

2016-02-01

Pyrolysis is the thermal degradation of organic material in oxygen-free or very lean oxygen atmosphere. This study evaluates the use of pyrolysis for conversion of leather wastes from chromium tanning processes into Carbonized Leather Residues (CLR), and the utilization of CLR in metallurgical processes through the production of iron ore pellets. CLR was used to replace mineral coal in proportions of 10% and 25% on fixed carbon basis content in the mixtures for pellets preparation. Experimental conversions were performed on a pilot scale pyrolysis plant and a pelletizing reactor of the "pot grate" type. The results demonstrated the technical feasibility of using the charcoal product from animal origin as an energy source, with recovery of up to 76.47% of chromium contained in CLR in the final produced of iron ore pellets. Pellets with 25% replacement of fixed carbon in the coal showed an enhanced compressive strength, with an average value of 344kgfpellet(-1), compared to 300kgfpellet(-1) for standard produced pellets. Copyright © 2015. Published by Elsevier Ltd.

Microstructural analyses of Cr(VI) speciation in chromite ore processing Residue (COPR)

DOE Office of Scientific and Technical Information (OSTI.GOV)

CHRYSOCHOOU, MARIA; FAKRA, SIRINE C .; Marcus, Matthew A.

2010-03-01

The speciation and distribution of Cr(VI) in the solid phase was investigated for two types of chromite ore processing residue (COPR) found at two deposition sites in the United States: gray-black (GB) granular and hard brown (HB) cemented COPR. COPR chemistry and mineralogy were investigated using micro-X-ray absorption spectroscopy and micro-X-ray diffraction, complemented by laboratory analyses. GB COPR contained 30percent of its total Cr(VI) (6000 mg/kg) as large crystals(>20 ?m diameter) of a previously unreported Na-rich analog of calcium aluminum chromate hydrates. These Cr(VI)-rich phases are thought to be vulnerable to reductive and pH treatments. More than 50percent of themore » Cr(VI) was located within nodules, not easily accessible to dissolved reductants, and bound to Fe-rich hydrogarnet, hydrotalcite, and possibly brucite. These phases are stable over a large pH range, thus harder to dissolve. Brownmilleritewasalso likely associated with physical entrapment of Cr(VI) in the interior of nodules. HB COPR contained no Cr(VI)-rich phases; all Cr(VI) was diffuse within the nodules and absent from the cementing matrix, with hydrogarnet and hydrotalcite being the main Cr(VI) binding phases. Treatment ofHBCOPRis challenging in terms of dissolving the acidity-resistant, inaccessible Cr(VI) compounds; the same applies to ~;;50percent of Cr(VI) in GB COPR.« less

Modifications to EPA Method 3060A to Improve Extraction of Cr(VI) from Chromium Ore Processing Residue-Contaminated Soils

USGS Publications Warehouse

Mills, Christopher T.; Bern, Carleton R.; Wolf, Ruth E.; Foster, Andrea L.; Morrison, Jean M.; Benzel, William M.

2017-01-01

It has been shown that EPA Method 3060A does not adequately extract Cr(VI) from chromium ore processing residue (COPR). We modified various parameters of EPA 3060A toward understanding the transformation of COPR minerals in the alkaline extraction and improving extraction of Cr(VI) from NIST SRM 2701, a standard COPR-contaminated soil. Aluminum and Si were the major elements dissolved from NIST 2701, and their concentrations in solution were correlated with Cr(VI). The extraction fluid leached additional Al and Si from the method-prescribed borosilicate glass vessels which appeared to suppress the release of Cr(VI). Use of polytetrafluoroethylene vessels and intensive grinding of NIST 2701 increased the amount of Cr(VI) extracted. These modifications, combined with an increased extraction fluid to sample ratio of ≥900 mL g–1 and 48-h extraction time resulted in a maximum release of 1274 ± 7 mg kg–1 Cr(VI). This is greater than the NIST 2701 certified value of 551 ± 35 mg kg–1 but less than 3050 mg kg–1 Cr(VI) previously estimated by X-ray absorption near edge structure spectroscopy. Some of the increased Cr(VI) may have resulted from oxidation of Cr(III) released from brownmillerite which rapidly transformed during the extractions. Layered-double hydroxides remained stable during extractions and represent a potential residence for unextracted Cr(VI).

Influence of ore processing activity on Hg, As and Sb contamination and fractionation in soils in a former mining site of Monte Amiata ore district (Italy).

PubMed

Protano, Giuseppe; Nannoni, Francesco

2018-05-01

A geochemical study was carried out at the former Abbadia San Salvatore (ASS) mining site of the Monte Amiata ore district (Italy). Hg, As and Sb total contents and fractionation using a sequential extraction procedure were determined in soil and mining waste samples. Ore processing activities provided a different contribution to Hg contamination and concentration in soil fractions, influencing its behaviour as volatility and availability. Soils of roasting zone showed the highest Hg contamination levels mainly due to the deposition of Hg released as Hg 0 by furnaces during cinnabar roasting. High Hg contents were also measured in waste from the lower part of mining dump due to the presence of cinnabar. The fractionation pattern suggested that Hg was largely as volatile species in both uncontaminated and contaminated soils and mining waste, and concentrations of these Hg species increased as contamination increased. These findings were in agreement with the fact that the ASS mining site is characterized by high Hg concentrations in the air and the presence of Hg 0 liquid droplets in soil. Volatile Hg species were also prevalent in uncontaminated soils likely because the Monte Amiata region is an area characterized by anomalous fluxes of gaseous Hg from natural and anthropogenic inputs. At the ASS mining site soils were also contaminated by Sb, while As contents were comparable with its local background in soil. In all soil and waste samples Sb and As were preferentially in residual fraction. Copyright © 2018 Elsevier Ltd. All rights reserved.

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... process alone or in conjunction with other processes, for the beneficiation of copper, lead, zinc, gold, silver, or molybdenum ores, or any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach processes to extract copper from ores or ore waste materials; and (4) Mills...

Dense Medium Ore Concentrates of Bois-Noirs; MINERAIS DES BOIS NOIRS CONCENTRES DE MILIEU DENSE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Le Bris, J.; Leduc, M.

1959-01-01

The chemical treatment of uranium concentrates of BoisNoirs ore obtained by heavy medium are discussed. The first part deals with sulfuric acid attack on the concentrate, and the second part with the separation of the solution from residues by filtration. A third part deals with this separation by decantation. The fourth part deals with the carbonation of the pickling solutions obtained. (auth)

Mobilization of Cr(VI) from chromite ore processing residue through acid treatment.

PubMed

Tinjum, James M; Benson, Craig H; Edil, Tuncer B

2008-02-25

Batch leaching studies on chromite ore processing residue (COPR) were performed using acids to investigate leaching of hexavalent chromium, Cr(VI), with respect to particle size, reaction time, and type of acid (HNO(3) and H(2)SO(4)). Aqueous Cr(VI) is maximized at approximately 0.04 mol Cr(VI) per kg of dry COPR at pH 7.6-8.1. Cr(VI) mobilized more slowly for larger particles, and the pH increased with time and increased more rapidly for smaller particles, suggesting that rate limitations occur in the solid phase. With H(2)SO(4), the pH stabilized at a higher value (8.8 for H(2)SO(4) vs. 8.0 for HNO(3)) and more rapidly (16 h vs. 30 h), and the differences in pH for different particle sizes were smaller. The acid neutralization capacity (ANC) of COPR is very large (8 mol HNO(3) per kg of dry COPR for a stable eluate pH of 7.5). Changes to the elemental and mineralogical composition and distribution in COPR particles after mixing with acid indicate that Cr(VI)-bearing solids dissolved. However, concentrations of Cr(VI) >2800 mg kg(-1) (>50% of the pre-treatment concentration) were still found after mixing with acid, regardless of the particle size, reaction time, or type of acid used. The residual Cr(VI) appears to be partially associated with poorly-ordered Fe and Al oxyhydroxides that precipitated in the interstitial areas of COPR particles. Remediation strategies that use HNO(3) or H(2)SO(4) to neutralize COPR or to maximize Cr(VI) in solution are likely to require extensive amounts of acid, may not mobilize all of the Cr(VI), and may require extended contact time, even under well-mixed conditions.

Idea of Identification of Copper Ore with the Use of Process Analyser Technology Sensors

NASA Astrophysics Data System (ADS)

Jurdziak, Leszek; Kaszuba, Damian; Kawalec, Witold; Król, Robert

2016-10-01

The Polish resources of the copper ore exploited by the KGHM S.A. underground mines are considered as one of the most complex in the world and - consequently - the most difficult to be processed. The ore consists of three lithology forms: dolomites, shales and sandstones but in different proportions which has a significant impact on the effectiveness of the grinding and flotation processes. The lithological composition of the ore is generally recognised in-situ but after being mined it is blended on its long way from various mining fields to the processing plant by the complex transportation system consisting of belt conveyors with numerous switching points, ore bunkers and shafts. Identification of the lithological composition of the ore being supplied to the processing plant should improve the adjustments of the ore processing machinery equipment aiming to decrease the specific processing (mainly grinding) energy consumption as well as increase the metal recovery. The novel idea of Process Analyser Technology (PAT) sensors - information carrying pellets, dropped into the transported or processed bulk material which can be read directly when needed - is investigated for various applications within the DISIRE project (a part of the SPIRE initiative, acting under the Horizon2020 framework program) and here is adopted for implementing the annotation the transported copper ore for the needs of ore processing plants control. The identification of the lithological composition of ore blended on its way to the processing plant can be achieved by an information system consisting of pellets that keep the information about the original location of the portions of conveyed ore, the digital, geological database keeping the data of in-situ lithology and the simulation models of the transportation system, necessary to evaluate the composition of the blended ore. The assumptions of the proposed solution and the plan of necessary in-situ tests (with the special respect to harsh environment of

Contamination analysis unit

DOEpatents

Gregg, H.R.; Meltzer, M.P.

1996-05-28

The portable Contamination Analysis Unit (CAU) measures trace quantities of surface contamination in real time. The detector head of the portable contamination analysis unit has an opening with an O-ring seal, one or more vacuum valves and a small mass spectrometer. With the valve closed, the mass spectrometer is evacuated with one or more pumps. The O-ring seal is placed against a surface to be tested and the vacuum valve is opened. Data is collected from the mass spectrometer and a portable computer provides contamination analysis. The CAU can be used to decontaminate and decommission hazardous and radioactive surfaces by measuring residual hazardous surface contamination, such as tritium and trace organics. It provides surface contamination data for research and development applications as well as real-time process control feedback for industrial cleaning operations and can be used to determine the readiness of a surface to accept bonding or coatings. 1 fig.

Contamination analysis unit

DOEpatents

Gregg, Hugh R.; Meltzer, Michael P.

1996-01-01

The portable Contamination Analysis Unit (CAU) measures trace quantifies of surface contamination in real time. The detector head of the portable contamination analysis unit has an opening with an O-ring seal, one or more vacuum valves and a small mass spectrometer. With the valve closed, the mass spectrometer is evacuated with one or more pumps. The O-ring seal is placed against a surface to be tested and the vacuum valve is opened. Data is collected from the mass spectrometer and a portable computer provides contamination analysis. The CAU can be used to decontaminate and decommission hazardous and radioactive surface by measuring residual hazardous surface contamination, such as tritium and trace organics It provides surface contamination data for research and development applications as well as real-time process control feedback for industrial cleaning operations and can be used to determine the readiness of a surface to accept bonding or coatings.

Process for recovering hydrocarbons from a diatomite-type ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Davis, B.W.

1983-02-15

A process for recovering hydrocarbons from a diatomite-type ore which comprises contacting the diatomite ore with a C/sub 4/-C/sub 10/ alcohol and thereafter contacting the diatomite ore-alcohol mixture with an aqueous alkaline solution to separate a hydrocarbon-alcohol phase and an alkaline aqueous phase containing the stripped diatomite ore. Thereafter, the alcohol is distilled off from the hydrocarbon phase and recycled back into the initial process.

Binding of Vapour-Phase Mercury (Hg0) on Chemically Treated Bauxite Residues (Red Mud)

EPA Science Inventory

In this study, Hg capture using red mud, seawater-neutralized red mud, and acid-treated red mud is evaluated and compared to other, more conventional sorbent materials. Red mud (also known as bauxite residue) is a by-product of extracting alumina from ground bauxite ore by treati...

Solvent extraction of diatomite

DOE Office of Scientific and Technical Information (OSTI.GOV)

Williams, W.

1984-07-24

There is provided a method of extracting hydrocarbons from a diatomite ore. The particle size of the ore is first reduced to form a processed ore. The processed ore is then mixed with a substantially irregular granular material to form an unstratified ore mixture having increased permeability to an extracting solvent. The unstratified ore mixture is then permeated with an extracting solvent to obtain a hydrocarbon-solvent stream from which hydrocarbons are subsequently separated. The irregular granular material may be sand.

Detoxification and immobilization of chromite ore processing residue in spinel-based glass-ceramic.

PubMed

Liao, Chang-Zhong; Tang, Yuanyuan; Lee, Po-Heng; Liu, Chengshuai; Shih, Kaimin; Li, Fangbai

2017-01-05

A promising strategy for the detoxification and immobilization of chromite ore processing residue (COPR) in a spinel-based glass-ceramic matrix is reported in this study. In the search for a more chemically durable matrix for COPR, the most critical crystalline phase for Cr immobilization was found to be a spinel solid solution with a chemical composition of MgCr 1.32 Fe 0.19 Al 0.49 O 4 . Using Rietveld quantitative X-ray diffraction analysis, we identified this final product is with the phases of spinel (3.5wt.%), diopside (5.2wt.%), and some amorphous contents (91.2wt.%). The partitioning ratio of Cr reveals that about 77% of the Cr was incorporated into the more chemically durable spinel phase. The results of Cr K-edge X-ray absorption near-edge spectroscopy show that no Cr(VI) was observed after conversion of COPR into a glass-ceramic, which indicates successful detoxification of Cr(VI) into Cr(III) in the COPR-incorporated glass-ceramic. The leaching performances of Cr 2 O 3 and COPR-incorporated glass-ceramic were compared with a prolonged acid-leaching test, and the results demonstrate the superiority of the COPR-incorporated glass-ceramic matrix in the immobilization of Cr. The overall results suggest that the use of affordable additives has potential in more reliably immobilizing COPR with a spinel-based glass-ceramic for safer disposal of this hazardous waste. Copyright © 2016 Elsevier B.V. All rights reserved.

Biogeochemical aspects of uranium mineralization, mining, milling, and remediation

USGS Publications Warehouse

Campbell, Kate M.; Gallegos, Tanya J.; Landa, Edward R.

2015-01-01

Natural uranium (U) occurs as a mixture of three radioactive isotopes: 238U, 235U, and 234U. Only 235U is fissionable and makes up about 0.7% of natural U, while 238U is overwhelmingly the most abundant at greater than 99% of the total mass of U. Prior to the 1940s, U was predominantly used as a coloring agent, and U-bearing ores were mined mainly for their radium (Ra) and/or vanadium (V) content; the bulk of the U was discarded with the tailings (Finch et al., 1972). Once nuclear fission was discovered, the economic importance of U increased greatly. The mining and milling of U-bearing ores is the first step in the nuclear fuel cycle, and the contact of residual waste with natural water is a potential source of contamination of U and associated elements to the environment. Uranium is mined by three basic methods: surface (open pit), underground, and solution mining (in situ leaching or in situ recovery), depending on the deposit grade, size, location, geology and economic considerations (Abdelouas, 2006). Solid wastes at U mill tailings (UMT) sites can include both standard tailings (i.e., leached ore rock residues) and solids generated on site by waste treatment processes. The latter can include sludge or “mud” from neutralization of acidic mine/mill effluents, containing Fe and a range of coprecipitated constituents, or barium sulfate precipitates that selectively remove Ra (e.g., Carvalho et al., 2007). In this chapter, we review the hydrometallurgical processes by which U is extracted from ore, the biogeochemical processes that can affect the fate and transport of U and associated elements in the environment, and possible remediation strategies for site closure and aquifer restoration.This paper represents the fourth in a series of review papers from the U.S. Geological Survey (USGS) on geochemical aspects of UMT management that span more than three decades. The first paper (Landa, 1980) in this series is a primer on the nature of tailings and radionuclide mobilization from them. The second paper (Landa, 1999) includes coverage of research carried out under the U.S. Department of Energy’s Uranium Mill Tailings Remedial Action Program (UMTRA). The third paper (Landa, 2004) reflects the increased focus of researchers on biotic effects in UMT environs. This paper expands the focus to U mining, milling, and remedial actions, and includes extensive coverage of the increasingly important alkaline in situ recovery and groundwater restoration.

Explosion-assisted preparation of dispersed gold-bearing different-grade ore for selective mining

NASA Astrophysics Data System (ADS)

Trubachev, AI; Zykov, NV

2017-02-01

It is found that there are transient zones (between quality and off-quality ore areas) with the respective content of useful component in an ore body, and a variant of explosive treatment of such zones before the selective mining is put forward. Practicability of two processing technologies is evaluated: processing of high-grade and low-grade ore from the transient zones and heap leaching of metals from the low-grade and impoverished ore. Open mining technology is conventional truck-and-shovel scheme, with distributed ore flows to processing plant and (or) to heap leaching, which generally enhances the mine efficiency.

Removal of iron ore slimes from a highly turbid water by DAF.

PubMed

Faustino, L M; Braga, A S; Sacchi, G D; Whitaker, W; Reali, M A P; Leal Filho, L S; Daniel, L A

2018-05-30

This paper addresses Dissolved Air Flotation (DAF) process variables, such as the flocculation parameters and the recycle water addition, as well as the pretreatment chemical variables (coagulation conditions), to determine the optimal values for the flotation of iron ore slimes found in a highly turbid water sample from the Gualaxo do Norte River, a tributary of the Doce River Basin in Minas Gerais, Brazil. This work was conducted using a flotatest batch laboratory-scale device to evaluate the effectiveness of DAF for cleaning the water polluted by the Samarco tailings dam leakage and determine the ability of DAF to reduce the water turbidity from 358 NTU to values below 100 NTU, aiming to comply with current legislation. The results showed that the four types of tested coagulants (PAC, ferric chloride, Tanfloc SG and Tanfloc SL) provided adequate conditions for coagulation, flocculation and flotation (in the range of 90-99.6% turbidity reduction). Although the process variables were optimized and low residual turbidity vales were achieved, results revealed that a portion of the flocs settled at the bottom of the flotatest columns, which indicated that the turbidity results represented removal caused by a combination of flotation and sedimentation processes simultaneously.

Revegetation strategies for bauxite refinery residue: a case study of Alcan Gove in Northern Territory, Australia.

PubMed

Wehr, J Bernhard; Fulton, Ian; Menzies, Neal W

2006-03-01

Alumina extraction from bauxite ore with strong alkali produces waste bauxite refinery residue consisting of residue sand and red mud. The amount and composition of refinery residue depend on the purity of the bauxite ore and extraction conditions, and differs between refineries. The refinery residue is usually stored in engineered disposal areas that eventually have to be revegetated. This is challenging because of the alkaline and sodic nature of the residue. At Alcan Gove's bauxite refinery in Gove, Northern Territory, Australia, research into revegetation of bauxite residue has been conducted since the mid-1970s. In this review, we discuss approaches taken by Alcan Gove to achieve revegetation outcomes (soil capping of refinery residue) on wet-slurry disposal areas. Problems encountered in the past include poor drainage and water logging during the wet season, and salt scalding and capillary rise during the dry season. The amount of available water in the soil capping is the most important determinant of vegetation survival in the seasonally dry climate. Vegetation cover was found to prevent deterioration of the soil cover by minimising capillary rise of alkalinity from the refinery residue. The sodicity and alkalinity of the residue in old impoundments has diminished slightly over the 25 years since it was deposited. However, development of a blocky structure in red mud, presumably due to desiccation, allows root penetration, thereby supplying additional water to salt and alkali-tolerant plant species. This has led to the establishment of an ecosystem that approaches a native woodland.

The Problem of Preconcentration of Uranium Ores by Physical Processes; LES PROBLEMES DE LA PRECONCENTRATION DES MINERAIS D'URANIUM PAR VOIE PHYSIQUE. LE TRIAGE ELECTRONIQUE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vuchot, L.; Ginocchio, A. et al.

1959-10-31

As uranium ores, like most other ores, are not definite substances which can be treated directly for the production of the metal, the ores must be concentrated. The common physical processes used for all ores, such as sieving, gravimetric separation, flotation, electromagnetic separation, and electrostatic separation, are applicable to the beneficiation of uranium. The radioactivity of uranium ores has led to a radiometric method for the concentration. This method is described in detail. As an example, the preconcentration of Forez ores is discussed. (J.S.R.)

Using apatite to discriminate synchronous ore-associated and barren granitoid rocks: A case study from the Edong metallogenic district, South China

NASA Astrophysics Data System (ADS)

Duan, Deng-Fei; Jiang, Shao-Yong

2018-06-01

In order to find criteria to discriminate the synchronous ore-associated and barren granitoid rocks, we have determined apatite chemistry associated with ore-associated (Cu-Au) and barren granitoid rocks in the Edong district of the Middle and Lower Yangtze River metallogenic belt, South China. Both rock types give zircon U-Pb ages between 135.0 and 138.7 Ma. Apatite has a higher volatile and Li content (Cl: 0.19-0.57 wt%, average 0.35 wt%, SO3: 0.08-0.71 wt%, average 0.32 wt%, Li: 0.49-7.99 ppm, average 3.23 ppm) in ore-associated rocks than those in barren rocks (Cl: 0.09-0.31 wt%, average 0.16 wt%, SO3: 0.06-0.28 wt%, average 0.16 wt%, Li: 0.15-0.89 ppm, average 0.36 ppm). Apatite (La/Yb)N ratios and Eu/Eu* values are relatively high and show wider variation in ore-associated rocks than those in barren rocks. Apatite (La/Sm)N and (Yb/Sm)N show positive correlation in ore-associated rocks but negative in barren rocks. The higher volatile content occurs in ore-associated magma, favoring Cu-Au transportation and deposition. Furthermore, amphibole fractional crystallization in ore-associated magma further enriched the ore elements in the residual melt. Barren rocks may have undergone fluid exsolution before emplacement, which makes it barren in Cl, S and ore elements (Cu, S). These signatures emphases the significance of volatile and magma evolution in mineralization and indicate that analyses of magmatic apatite can serve to distinguish ore-associated from barren intrusions.

Intensification of the Reverse Cationic Flotation of Hematite Ores with Optimization of Process and Hydrodynamic Parameters of Flotation Cell

NASA Astrophysics Data System (ADS)

Poperechnikova, O. Yu; Filippov, L. O.; Shumskaya, E. N.; Filippova, I. V.

2017-07-01

The demand of high grade iron ore concentrates is a major issue due to the depletion of rich iron-bearing ores and high competitiveness in the iron ore market. Iron ore production is forced out to upgrade flowsheets to decrease the silica content in the pelettes. Different types of ore have different mineral composition and texture-structural features which require different mineral processing methods and technologies. The paper presents a comparative study of the cationic and anionic flotation routes to process a fine-grain oxidized iron ore. The modified carboxymethyl cellulose was found as the most efficient depressant in reverse cationic flotation. The results of flotation optimization of hematite ores using matrix of second-order center rotatable uniform design allowed to define the collector concentration, impeller rotation speed and air flowrate as the main flotation parameters impacting on the iron ore concentrate quality and iron recovery in a laboratory flotation machine. These parameters have been selected as independent during the experiments.

Engineering, construction, and operations in space

NASA Technical Reports Server (NTRS)

Johnson, Stewart W. (Editor); Wetzel, John P. (Editor)

1990-01-01

The century-old Mond process for carbonyl extraction of metals from ore shows great promise as an efficient low energy scheme for producing high-purity Fe, Ni, Cr, Mn, and Co from lunar or asteroidal feedstocks. Scenarios for winning oxygen from the lunar regolith can be enhanced by carbonyl processing of the metallic alloy by-products of such operations. The native metal content of asteroidal regoliths is even more suitable to carbonyl processing. High-purity, corrosion resistant Fe and Ni can be extracted from asteroidial feedstocks along with a Co-rich residue containing 0.5 percent platinum-group metals. The resulting gaseous metal carbonyl can produce a variety of end products using efficient vapor forming techniques.

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.11640 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production Area... subject to this subpart if you own or operate a gold mine ore processing and production facility as... source. The affected sources are each collection of “ore pretreatment processes” at a gold mine ore...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2014 CFR

2014-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2011 CFR

2011-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2012 CFR

2012-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2013 CFR

2013-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

40 CFR 63.9582 - What parts of my plant does this subpart cover?

Code of Federal Regulations, 2010 CFR

2010-07-01

... CATEGORIES (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing... applies to each new and existing affected source at your taconite iron ore processing plant. (b) The affected sources are each new or existing ore crushing and handling operation, ore dryer, indurating...

Physical-chemical conditions of ore deposition

USGS Publications Warehouse

Barton, P.B.

1981-01-01

Ore deposits form under a wide range of physical and chemical conditions, but those precipitating from hot, aqueous fluids-i.e. the hydrothermal deposits-form generally below 700??C and at pressures of only 1 or 2 kbar or less. Natural aqueous fluids in rocks may extract metal and sulfur from a variety of rock types or may acquire them as a residual heritage from a crystallizing silicate magma. Ore-forming hydrothermal fluids never appear as hot springs (except in deep, submarine situations) because they boil, mix with surface waters, and cool, thereby losing their ore-bearing ability before reaching the surface. Mineral systems function as chemical buffers and indicators just as buffers and indicators function in a chemical laboratory. By reading the record written in the buffer/indicator assemblages of minerals one can reconstruct many aspects of the former chemical environment. By studying the record of changing conditions one may deduce information regarding the processes functioning to create the succession of chemical environments and the ore deposits they represent. The example of the OH vein at Creede, Colorado, shows a pH buffered by the K-feldspar + muscovite + quartz assemblage and the covariation of S2 and O2 buffered by the assemblage chlorite + pyrite + quartz. Boiling of the ore fluid led to its oxidation to hematite-bearing assemblages and simultaneously produced an intensely altered, sericitic capping over the vein in response to the condensation of vapors bearing acidic components. The solubility of metals as calculated from experimental and theoretical studies of mineral solubility appears too low by at least one or two powers of ten to explain the mineralization at Creede. In contrast to Creede where the mineral stabilities all point to a relatively consistent chemistry, the Mississippi Valley type deposits present a puzzle of conflicting chemical clues that are impossible to reconcile with any single equilibrium situation. Thus we must seriously consider metastable equilibria; those most likely involve redox disequilibrium among the sulfur species in solution and perhaps also involve organic compounds. ?? 1981.

Holistic processing, contact, and the other-race effect in face recognition.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-12-01

Face recognition, holistic processing, and processing of configural and featural facial information are known to be influenced by face race, with better performance for own- than other-race faces. However, whether these various other-race effects (OREs) arise from the same underlying mechanisms or from different processes remains unclear. The present study addressed this question by measuring the OREs in a set of face recognition tasks, and testing whether these OREs are correlated with each other. Participants performed different tasks probing (1) face recognition, (2) holistic processing, (3) processing of configural information, and (4) processing of featural information for both own- and other-race faces. Their contact with other-race people was also assessed with a questionnaire. The results show significant OREs in tasks testing face memory and processing of configural information, but not in tasks testing either holistic processing or processing of featural information. Importantly, there was no cross-task correlation between any of the measured OREs. Moreover, the level of other-race contact predicted only the OREs obtained in tasks testing face memory and processing of configural information. These results indicate that these various cross-race differences originate from different aspects of face processing, in contrary to the view that the ORE in face recognition is due to cross-race differences in terms of holistic processing. Copyright © 2014 The Authors. Published by Elsevier Ltd.. All rights reserved.

40 CFR 63.11651 - What definitions apply to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... mine ore at gold mine ore processing and production facilities prior to the cyanide leaching process... are generated from leaching gold ore with a dilute cyanide solution. Quenching means a process in... the presence of steam, after the gold has been stripped from the carbon. Carbon processes with mercury...

Distribution of uranium in the Bisbee district, Cochise County, Arizona

USGS Publications Warehouse

Wallace, Stewart R.

1956-01-01

The Bisbee district has been an important source of copper for many years, and substantial amounts of lead and zinc ore and minor amounts of manganese ore have been mined during certain periods. The copper deposits occur both as low-grade disseminated ore in the Sacramento Hill stock and as massive sulfide (and secondary oxide and carbonate) replacement bodies in Paleozoic limestones that are intruded by the stock and related igneous bodies. The lead-zinc production has come almost entirely from limestone replacement bodies. The disseminated ore exhibits no anomalous radioactivity, and samples from the Lavender pit contain from 0.002 to less than 0.001 percent equivalent uranium. The limestone replacement ores are distinctly radioactive and stoping areas can be readily distinguished from from unmineralized ground on the basis of radioactivity alone. The equivalent uranium content of the copper replacement ores ranges from 0.002 to 0.014 percent and averages about 0.005 percent; the lead-zinc replacement ores average more than 0.007 percent equivalent uranium. Most of the uranium in the copper ores of the district is retained in the smelter slag of a residual concentrate; the slag contains about 0.009 percent equivalent uranium. Uranium carried off each day by acid mine drainage is roughly equal to 1 percent of that being added to the slag dump. Although the total amount of uranium in the district is large, no minable concentrations of ore-grade material are known; samples of relatively high-grade material represent only small fractions of tons at any one locality.

Method of winning aluminum metal from aluminous ore

DOEpatents

Loutfy, Raouf O.; Keller, Rudolf; Yao, Neng-Ping

1981-01-01

Aluminous ore such as bauxite containing alumina is blended with coke or other suitable form of carbon and reacted with sulfur gas at an elevated temperature. For handling, the ore and coke can be extruded into conveniently sized pellets. The reaction with sulfur gas produces molten aluminum sulfide which is separated from residual solid reactants and impurities. The aluminum sulfide is further increased in temperature to cause its decomposition or sublimation, yielding aluminum subsulfide liquid (AlS) and sulfur gas that is recycled. The aluminum monosulfide is then cooled to below its disproportionation temperature to again form molten aluminum sulfide and aluminum metal. A liquid-liquid or liquid-solid separation, depending on the separation temperature, provides product aluminum and aluminum sulfide for recycle to the disproportionation step.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE... that produce gold or gold bearing ores from placer deposits; and (2) The beneficiation processes which... yards (cu yd) of ore per year, or to dredges which process less than 50,000 cu yd of ore per year, or to...

A brief history of the American radium industry and its ties to the scientific community of its early twentieth century

USGS Publications Warehouse

Landa, E.R.

1993-01-01

Federally funded remedial action projects are presently underway in New Jersey and Colorado at sites containing 226Ra and other radionuclides from radium-uranium ore extraction plants that operated during the early twentieth century. They are but the latest chapter in the story of an American industry that emerged and perished in the span of three decades. Major extraction plants were established in or near Denver (CO), Pittsburgh (PA), and New York City (NY) to process radium from ore that came largely from the carnotite deposits of western Colorado and eastern Utah. The staffs of these plants included some of the finest chemists and physicists in the nation, and the highly-refined radium products found a variety of uses in medicine and industry. The discovery of high-grade pitchblende ores in the Belgian Congo and the subsequent opening of an extraction plant near Antwerp, Belgium, in 1992, however, created an economic climate that put an end to the American radium industry. The geologic, chemical, and engineering information gathered during this era formed the basis of the uranium industry of the later part of the century, while the tailings and residues came to be viewed as environmental problems during the same period.

Mineralogical and geochemical features of the alteration processes of magmatic ores in the Beni Bousera ultramafic massif (north Morocco)

NASA Astrophysics Data System (ADS)

Hajjar, Zaineb; Gervilla, Fernando; Essaifi, Abderrahim; Wafik, Amina

2017-08-01

The Beni Bousera ultramafic massif (Internal Rif, Morocco) is characterized by the presence of two types of small-scale magmatic mineralizations (i) a mineralization consisting mainly of chromite and Ni arsenides associated to orthopyroxene and cordierite (Cr-Ni ores), and (ii) a mineralization mainly composed of magmatic Fe-Ni-Cu sulfides containing variable amounts of graphite and chromite associated to phlogopite, clinopyroxène and plagioclase (S-G ores). Theses ores underwent High-T (450-550 °C) and Low-T (150-300 °C) alteration processes. The High-T alteration processes are tentatively related to intrusion of leucogranite dykes. They are preserved in the Galaros Cr-Ni ore deposit where nickeline is partly dissolved and transformed to maucherite, and orthopyroxene alters to phlogopite. Ni and Co were mobilized to the fluid phase, rising up their availability and promoting their diffusion into chromite and phlogopite, which have significantly higher contents in Ni and Co in phlogopite-rich ores than in orthopyroxene- and nickeline-rich ones. The Low-T alteration processes are related to serpentinization/weathering spatially associated with a regional shear zone. They affected both the Cr-Ni and S-G ores. In the Cr-Ni ores, Ni-arsenides were completely leached out while chromite is fractured within a matrix of chlorite, vermiculite and Ni-rich serpentine. In S-G ores, the silicates were altered into amphibole, Fe-rich chlorite and pectolite in clinopyroxene- and plagioclase-bearing ores while sulfides were completely leached out in phlogopite-bearing ores where iron oxides and hydroxides, and Fe-rich vermiculite were deposited. Chromite composition is not affected by the Low-T alteration processes.

Microbial biogeochemistry of uranium mill tailings

USGS Publications Warehouse

Landa, Edward R.

2005-01-01

Uranium mill tailings (UMT) are the crushed ore residues from the extraction of uranium (U) from ores. Among the radioactive wastes associated with the nuclear fuel cycle, UMT are unique in terms of their volume and their limited isolation from the surficial environment. For this latter reason, their management and long-term fate has many interfaces with environmental microbial communities and processes. The interactions of microorganisms with UMT have been shown to be diverse and with significant consequences for radionuclide mobility and bioremediation. These radionuclides are associated with the U-decay series. The addition of organic carbon and phosphate is required to initiate the reduction of the U present in the groundwater down gradient of the mills. Investigations on sediment and water from the U-contaminated aquifer, indicates that the addition of a carbon source stimulates the rate of U removal by microbial reduction. Moreover, most attention with respect to passive or engineered removal of U from groundwaters focuses on iron-reducing and sulfate-reducing bacteria.

40 CFR 440.140 - Applicability; description of the gold placer mine subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold... gold bearing ores from placer deposits; and (2) The beneficiation processes which use gravity... applicable to any mines or beneficiation processes which process less than 1500 cubic yards (cu yd) of ore...

Long-term stability of FeSO4 and H2SO4 treated chromite ore processing residue (COPR): Importance of H+ and SO42.

PubMed

Wang, Xin; Zhang, Jingdong; Wang, Linling; Chen, Jing; Hou, Huijie; Yang, Jiakuan; Lu, Xiaohua

2017-01-05

In this study, the long-term stability of Cr(VI) in the FeSO 4 and H 2 SO 4 (FeSO 4 -H 2 SO 4 ) treated chromite ore processing residue (COPR) after 400 curing days and the stabilization mechanisms were investigated. FeSO 4 -H 2 SO 4 treatment significantly reduced toxicity characteristic leaching procedure (TCLP) and synthetic precipitation leaching procedure (SPLP) Cr(VI) concentrations to lower than the regulatory limit of 1.5mgL -1 (HJ/T 301-2007, China EPA) even for the samples curing 400days, achieving an outstanding long-term stability. Our independent leaching tests revealed that H + and SO 4 2- have synergistic effect on promoting the release of Cr(VI), which would make Cr(VI) easier accessed by Fe(II) during stabilization. The contributions of H + and SO 4 2- to Cr(VI) release ratio were 25%-44% and 19%-38%, respectively, as 5mol H 2 SO 4 per kg COPR was used. X-ray powder diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and alkaline digestion analyses were also employed to interpret the possible stabilization mechanism. Cr(VI) released from COPR solid was reduced to Cr(III) by Fe(II), and then formed stable Fe x Cr (1-x) (OH) 3 precipitate. This study provides a facile and reliable scheme for COPR stabilization, and verifies the excellent long-term stability of the FeSO 4 -H 2 SO 4 treated COPR. Copyright © 2016 Elsevier B.V. All rights reserved.

Assessment of ferrous chloride and Portland cement for the remediation of chromite ore processing residue.

PubMed

Jagupilla, Santhi C; Wazne, Mahmoud; Moon, Deok Hyun

2015-10-01

Chromite Ore Processing Residue (COPR) is an industrial waste containing up to 7% chromium (Cr) including up to 5% hexavalent chromium [Cr(VI)]. The remediation of COPR has been challenging due to the slow release of Cr(VI) from a clinker like material and thereby the incomplete detoxification of Cr(VI) by chemical reagents. The use of sulfur based reagents such as ferrous sulfate and calcium polysulfide to detoxify Cr(VI) has exasperated the swell potential of COPR upon treatment. This study investigated the use of ferrous chloride alone and in combination with Portland cement to address the detoxification of Cr(VI) in COPR and the potential swell of COPR. Chromium regulatory tests, X-ray powder diffraction (XRPD) analyses and X-ray absorption near edge structure (XANES) analyses were used to assess the treatment results. The treatment results indicated that Cr(VI) concentrations for the acid pretreated micronized COPR as measured by XANES analyses were below the New Jersey Department of Environmental Protection (NJDEP) standard of 20 mg kg(-1). The Toxicity characteristic leaching procedure (TCLP) Cr concentrations for all acid pretreated samples also were reduced below the TCLP regulatory limit of 5 mg L(-1). Moreover, the TCLP Cr concentration for the acid pretreated COPR with particle size ⩽0.010 mm were less than the universal treatment standard (UTS) of 0.6 mg L(-1). The treatment appears to have destabilized all COPR potential swell causing minerals. The unconfined compressive strength (UCS) for the treated samples increased significantly upon treatment with Portland cement. Copyright © 2015 Elsevier Ltd. All rights reserved.

High-resolution analyses reveal structural diversity patterns of microbial communities in Chromite Ore Processing Residue (COPR) contaminated soils.

PubMed

Min, Xiaobo; Wang, Yangyang; Chai, Liyuan; Yang, Zhihui; Liao, Qi

2017-09-01

To explore how heavy metal contamination in Chromite Ore Processing Residue (COPR) disposal sites determine the dissimilarities of indigenous microbial communities, 16S rRNA gene MiSeq sequencing and advanced statistical methods were applied. 13 soil samples were collected from three COPR disposal sites in Mouding of southwestern, Shangnan of northwestern and Yima of central China. The results of analyses of variance (ANOVA), similarities (ANOSIM), and non-metric multidimensional scaling (NMDS) showed that the structural diversity of the microbial communities in the samples with high total chromium (Cr) content (more than 300 mg kg -1 ; High group) were significantly lesser than in the Low group (less than 90 mg kg -1 ) regardless of their geographical distribution. But their diversity had virtually rehabilitated under the pressures of long-term metal contamination. Furthermore, the similarity percentage (SIMPER) analysis indicated that the major dissimilarity contributors Micrococcaceae, Delftia, and Streptophyta, possibly having Cr(VI)-resistant and/or Cr(VI)-reducing capability, were dominant in the High group, while Ramlibacter and Gemmatimonas with potential resistances to other heavy metals were prevalent in the Low group. In addition, the multivariate regression tree (MRT), aggregated boosted tree (ABT), and Mantel test revealed that total Cr content affiliated with Cr(VI) was the principal factor shaping the dissimilarities between the soil microbial communities in the COPR sites. Our findings provide a deep insight of the influence of these heavy metals on the microbial communities in the COPR disposal sites and will facilitate bioremediation on such site. Copyright © 2017 Elsevier Ltd. All rights reserved.

Determining Prehistoric Mining Practices in Southeastern Europe Using Copper Isotopes

NASA Astrophysics Data System (ADS)

Powell, Wayne; Mathur, Ryan; Bankoff, H. Arthur; Bulatović, Aleksandar; Filipović, Vojislav

2017-04-01

Copper was first smelted from malachite at 5000 BCE in Serbia. There the Eneolithic (Copper Age) began with the production of small jewelry pieces and progressed to the casting of massive copper tools near its end, approximately 2000 years later. However, copper metallurgy in southeastern Europe ceased or significantly decreased in the later third millennium, several centuries before the Bronze Age began. Whether this metallurgical hiatus was the result a cultural shift or depletion of natural resources remains an ongoing subject of debate. It has been speculated that the marked reduction in metal production at the Eneolithic-Bronze Age transition was due to the exhaustion of surficial weathered oxide ores and the technical inability to smelt the underlying sulfide minerals. The behavior of copper isotopes in near-surface environments allows us to differentiate highly weathered oxide ores that occur at Earth's surface from non-weathered sulfide ores that occur at greater depth. The oxidation of copper generates fluids and associated minerals that are enriched in the 65Cu isotope. Thus, oxidative weathering of sulfide ores leads to the development of three stratified isotopic reservoirs for copper: 1) oxides above the water table that are enriched in 65Cu; 2) residual weathered sulfides minerals at the water table that are depleted in 65Cu; and 3) non-fractionated, non-weathered sulfide ore below the water table. And so, the transformative shift to sulfide-based metallurgy will be delineated by a significant decrease in δ65Cu in copper artifacts corresponding to the first use of 65Cu-depleted residual ore. The degree of variability of primary ore composition from numerable ore deposits would likely result in the overlap of copper isotope composition between populations of artifacts. Therefore, shifts in the mean copper isotope values and associated standard deviations would best reflect changes in ores use. A baseline value of -0.2‰ ±0.5 (1) was determined from an average of 164 published measurements from chalcopyrite and bornite from 8 epithermal and massive sulfide deposits. Twenty-two (88%) of Eneolithic artifacts (n=25) have values greater than this, whereas eight (73%) of the Early Bronze age artifacts (n=11) yield compositions less than -0.2‰. The mean of Middle Bronze Age, Late Bronze Age and Early Iron Age (n=86) cluster near -0.2‰. This pattern is consistent with a progression to the mining of ore assemblages from increasing depths through prehistory. The shift from 65Cu-enriched to 65Cu-depleted copper in artifacts across the Eneolithic-Bronze Age boundary at 2500 BCE indicates that accessible near-surface oxide ore reserves were depleted after approximately two millennia of mining, and that the beginning of the Bronze Age in the Balkans corresponded to the acquisition of pyrotechnology which allowed for the extraction of metals from sulfide minerals and the resumption of copper mining activity in the region.

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

40 CFR 63.9581 - Am I subject to this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This Subpart... taconite iron ore processing plant that is (or is part of) a major source of hazardous air pollutant (HAP) emissions on the first compliance date that applies to you. Your taconite iron ore processing plant is a...

Method of winning aluminum metal from aluminous ore

DOEpatents

Loutfy, R.O.; Keller, R.; Yao, N.P.

Aluminous ore such as bauxite containing alumina is blended with coke or other suitable form of carbon and reacted with sulfur gas at an elevated temperature. For handling, the ore and coke can be extruded into conveniently sized pellets. The reaction with sulfur gas produces molten aluminum sulfide which is separated from residual solid reactants and impurities. The aluminum sulfide is further increased in temperature to cause its decomposition or sublimation, yielding aluminum subsulfide liquid (A1S) and sulfur gas that is recycled. The aluminum monosulfide is then cooled to below its disproportionation temperature to again form molten aluminum sulfide and aluminum metal. A liquid-liquid or liquid-solid separation, depending on the separation temperature, provides product aluminum and aluminum sulfide for recycle to the disproportionation step.

Fiber size and number in workers exposed to processed chrysotile asbestos, chrysotile miners, and the general population

DOE Office of Scientific and Technical Information (OSTI.GOV)

Churg, A.; Wiggs, B.

1986-01-01

We analyzed chrysotile and chrysotile-associated amphibole (largely tremolite) asbestos fibers in 21 workers exposed to various types of processed (milled) chrysotile ore, 20 long-term chrysotile miners, and 20 members of the general population (controls). Significantly greater amounts of both chrysotile and tremolite were found in processed-ore workers and miners than in controls. On average, the mean fiber lengths and aspect ratios for the mining and processed-ore-exposed workers were similar and were significantly greater than the values seen in the controls; within the processed-ore group, there was a marked variation in these parameters, and some workers appeared to be exposed tomore » fairly long, thin fibers. It was found empirically that the fiber size data, and to a lesser extent the concentration data, could be used to classify workers accurately into those with processed-ore exposure and controls. We conclude that fiber sizes in the lungs of processed-ore-exposed workers are similar to those of chrysotile miners and are considerably longer than those found in the general population; some processed-ore workers have longer fibers which might be responsible for higher disease incidences in certain working groups; tremolite accompanies chrysotile in a variable proportion of workers exposed to processed chrysotile products and might be important in the genesis of mesothelioma in such workers; and mineralogic analysis will usually detect exposure even when chrysotile has largely disappeared from lung tissue.« less

Stochastic production phase design for an open pit mining complex with multiple processing streams

NASA Astrophysics Data System (ADS)

Asad, Mohammad Waqar Ali; Dimitrakopoulos, Roussos; van Eldert, Jeroen

2014-08-01

In a mining complex, the mine is a source of supply of valuable material (ore) to a number of processes that convert the raw ore to a saleable product or a metal concentrate for production of the refined metal. In this context, expected variation in metal content throughout the extent of the orebody defines the inherent uncertainty in the supply of ore, which impacts the subsequent ore and metal production targets. Traditional optimization methods for designing production phases and ultimate pit limit of an open pit mine not only ignore the uncertainty in metal content, but, in addition, commonly assume that the mine delivers ore to a single processing facility. A stochastic network flow approach is proposed that jointly integrates uncertainty in supply of ore and multiple ore destinations into the development of production phase design and ultimate pit limit. An application at a copper mine demonstrates the intricacies of the new approach. The case study shows a 14% higher discounted cash flow when compared to the traditional approach.

75 FR 28227 - National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-05-20

... published a proposed rule for mercury emissions from the gold mine ore processing and production area source... proposed rule (75 FR 22470). Several parties requested that EPA extend the comment period. EPA has granted...-AP48 National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

Perfection Of Methods Of Mathematical Analysis For Increasing The Completeness Of Subsoil Development

NASA Astrophysics Data System (ADS)

Fokina, Mariya

2017-11-01

The economy of Russia is based around the mineral-raw material complex to the highest degree. The mining industry is a prioritized and important area. Given the high competitiveness of businesses in this sector, increasing the efficiency of completed work and manufactured products will become a central issue. Improvement of planning and management in this sector should be based on multivariant study and the optimization of planning decisions, the appraisal of their immediate and long-term results, taking the dynamic of economic development into account. All of this requires the use of economic mathematic models and methodsApplying an economic-mathematic model to determine optimal ore mine production capacity, we receive a figure of 4,712,000 tons. The production capacity of the Uchalinsky ore mine is 1560 thousand tons, and the Uzelginsky ore mine - 3650 thousand. Conducting a corresponding analysis of the production of OAO "Uchalinsky Gok", an optimal production plan was received: the optimal production of copper - 77961,4 rubles; the optimal production of zinc - 17975.66 rubles. The residual production volume of the two main ore mines of OAO "UGOK" is 160 million tons of ore.

On prediction and discovery of lunar ores

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, Russell O.; Vaniman, David

1991-01-01

Sampling of lunar material and remote geochemical, mineralogical, and photogeologic sensing of the lunar surface, while meager, provide first-cut information about lunar composition and geochemical separation processes. Knowledge of elemental abundances in known lunar materials indicates which common lunar materials might serve as ores if there is economic demand and if economical extraction processes can be developed, remote sensing can be used to extend the understanding of the Moon's major geochemical separations and to locate potential ore bodies. Observed geochemical processes might lead to ores of less abundant elements under extreme local conditions.

PROCESS FOR THE CONCENTRATION OF ORES CONTAINING GOLD AND URANIUM

DOEpatents

Gaudin, A.M.; Dasher, J.

1958-06-10

ABS>A process is described for concentrating certain low grade uranium and gold bearing ores, in which the gangue is mainly quartz. The production of the concentrate is accomplished by subjecting the crushed ore to a froth floatation process using a fatty acid as a collector in conjunction with a potassium amyl xanthate collector. Pine oil is used as the frothing agent.

Natural attenuation of Cr(VI) contaminated groundwater at two industrial sites in the eastern U.S.A.: A Cr isotope study

NASA Astrophysics Data System (ADS)

Novak, Martin; Hellerich, Lucas A.; Sebek, Ondrej; Andronikov, Alexandre; Chrastny, Vladislav; Curik, Jan; Stepanova, Marketa; Pacherova, Petra; Martinkova, Eva; Prechova, Eva; Veselovsky, Frantisek

2017-04-01

Hexavalent chromium [Cr(VI)], found in various compartments of the environment, has generated much interest due to its extreme toxicity and mobility. We studied natural attenuation of Cr(VI)-contaminated groundwater at one site in Connecticut (site A), and one site in New Jersey (site B), U.S.A. Shallow groundwater was contaminated by electroplating solutions at site A, and by water-soluble chromite ore-processing residues at site B. Site A had lower Cr(VI) concentrations of less than 1 mg L-1 in comparison to site B (200 mg L-1). Site A also had lower mean del53Cr values (1.4 per mil) than site B (2.9 per mil). Chromium isotope composition of the pollution sources (plating bath, ore) was known (del53Cr of 0.0 to 0.2 per mil). The positive Cr isotope shift from the pollution source Cr(VI) to groundwater Cr(VI) at both sites indicated that spontaneous Cr(VI) reduction to insoluble Cr(III) is under way. This process is removing toxicity from the groundwater. Del53Cr values of groundwater were strongly positively correlated with the concentration of dissolved organic carbon (DOC), but not with divalent Fe and Mn, indicating that DOC may be the main Cr-reducing agent. A Rayleigh model indicated that 30 and 57 % of the original contaminant may have been removed from the groundwater by natural attenuation at site A and B, respectively. Interestingly, del53Cr values of the residual Cr(VI) in the groundwater at site A decreased significantly over the past 15 years, during which the water is being extracted for chemical treatment. At present, older, less fractionated Cr(VI) may be extracted at site A.

Silicophosphate Sorbents, Based on Ore-Processing Plants' Waste in Kazakhstan

ERIC Educational Resources Information Center

Kubekova, Sholpan N.; Kapralova, Viktoria I.; Telkov, Shamil A.

2016-01-01

The problem of ore-processing plants' waste and man-made mineral formations (MMF) disposal is very important for the Republic of Kazakhstan. The research of various ore types (gold, polymetallic, iron-bearing) MMF from a number of Kazakhstan's deposits using a complex physical and chemical methods showed, that the waste's main components are…

A Late Variscan Sn province: the Arburese region (SW Sardinia, Italy)

NASA Astrophysics Data System (ADS)

Naitza, Stefano; Secchi, Francesco; Oggiano, Giacomo; Cuccuru, Stefano

2015-04-01

Late Variscan Sn - rich European provinces (e. g. Erzgebirge, Cornwall) are of particular relevance as they offer key insights into crustal evolution, intrusive processes and ore genesis. In Sardinia (Italy), small Sn deposits are only known in the Arburese historical mining region (SW Sardinia), hosted in low-grade metamorphics close to the contacts with intrusives. This region is characterised by two late variscan intrusions, which differ in age and composition: the Arbus and the Monte Linas pluton, aging 304 ± 1 Ma, and 289 ± 1 Ma respectively. They emplaced at shallow crustal levels and crosscut the basal thrust between the alloctonous prism and the foreland of the Variscan belt of Sardinia. The Arbus Pluton (AP) is a composite intrusion of piroxene- and amphibole- granodiorites hosting minor amounts of monzogabbroic rocks and cordierite-bearing granites with a wide core of leuco-monzogranites. Tourmaline greisens and pegmatites garnish the contact between the border facies and the host metamorphic rocks. The Monte Linas Pluton (MLP) has biotite monzogranite composition. The pluton is internally zoned, from medium grained monzogranite in the core to hololeucocratic fine-grained rock-types at the top, where often F-greisen, fayalite-pegmatite pods and sill are common. In both plutons the igneous associations are high-K ilmenite series, suggesting derivation from low- fO2 magmas possibly linked to a common crustal contribution; however, in the Linas Pluton magnetite in the fine-grained facies may indicate an increase in oxygen fugacity. The AP-related Sn ores consist of high-temperature As-Sn quartz veins. They are vertically zoned, from quartz-chlorite-cassiterite to large quartz-arsenopyrite veins. Ore microscopy and SEM-EDS analyses evidenced a vein texture made of thick idiomorphic and frequently twinned cassiterite crystals, alternated with several generations of banded/geodic quartz. Chlinoclore aggregates are included into the quartz. The arsenopyrite ore shows alternating bands of microgranular to crystalline millimetric arsenopyrite with quartz. Field and analytical data suggest genetic mechanisms dominated by mobilization of residual Sn by chloride and other complexes in reducing, As- and S- rich, low- fO2 juvenile fluids. Cassiterite and successive arsenopyrite precipitation occurred under changing physicochemical conditions (e.g. oxygen contents; temperature decrease; pH). The MLP Sn metallogeny include Sn- Pb-Zn-Cu veins (Canale Serci old mine). Cassiterite occurs as fine-grained corroded crystals. Optical and SEM-EDS analyses evidence a high-temperature oxide stage (quartz-chlorite- cassiterite) followed, after brecciation, by mesothermal sulfide stages, with progressive deposition of sphalerite, pyrite, chalcopyrite, tetrahedrite, galena, marcasite. Arsenopyrite is strikingly absent. These evidences indicate possible derivation of the ore from residual, reducing juvenile fluids, capable to carry Sn- complexes from monzogranite magmas from which cassiterite precipitated in consequence of an increasing in fO2. Despite their limited amount, the Sn ores of SW Sardinia have high metallogenic relevance, indicating the persistence, of geochemical conditions,which lasted 15 Ma, favorable to the genesis of a Sn metallogenic province.

Production of Titanium Metal by an Electrochemical Molten Salt Process

NASA Astrophysics Data System (ADS)

Fatollahi-Fard, Farzin

Titanium production is a long and complicated process. What we often consider to be the standard method of primary titanium production (the Kroll process), involves many complex steps both before and after to make a useful product from titanium ore. Thus new methods of titanium production, especially electrochemical processes, which can utilize less-processed feedstocks have the potential to be both cheaper and less energy intensive than current titanium production processes. This project is investigating the use of lower-grade titanium ores with the electrochemical MER process for making titanium via a molten salt process. The experimental work carried out has investigated making the MER process feedstock (titanium oxycarbide) with natural titanium ores--such as rutile and ilmenite--and new ways of using the MER electrochemical reactor to "upgrade" titanium ores or the titanium oxycarbide feedstock. It is feasible to use the existing MER electrochemical reactor to both purify the titanium oxycarbide feedstock and produce titanium metal.

Analytical and mineralogical study of a Ghana manganese ore: Quantification of Mn speciation and effect of mechanical activation.

PubMed

He, Hongping; Cao, Jianglin; Duan, Ning

2016-11-01

In-depth understanding of the manganese ore would be beneficial to make the best use more environmental-friendly. A Ghana manganese ore before/after mechanical activation (MA) was therefore extensively characterized in our investigation. Surface Mn(4+)(35.5%), Mn(3+)(35.9%), Mn(2+)(28.6%) were detected by XPS, though XRD only revealed the presence of Mn(2+)-containing minerals. Thermal decomposition curve of manganese ore obtained by TG-DSC was divided into four stages from 373.15 K to 1273.15 K, which were quite consistent with the pattern of generated gases obtained by TG-FTIR and the theoretical thermodynamics analysis of the incorporated components involving ΔGT(θ) and Kp(θ). Mn species distribution showed no difference for manganese ores before/after MA, but quantitative analysis showed the decrease of residual Mn content (cannot be extracted effectively by acid, from about 12% to 1%), and thereby the increased contents of other four Mn species (exchangeables, carbonates, oxides, organics), which was suggested to be correlated with the dissociation of Mn-containing flocs and SiO2 particles witnessed by SEM-EDS. It was also found that MA could obviously promote the Mn dissolution kinetics in acid condition, though the dissolution of manganese ore before/after MA were both diffusion controlled. This investigation gives benignant inspiration for the resource utilization of manganese ore, taking the increasingly severer situation of Mn resource supply into consideration. Copyright © 2016 Elsevier Ltd. All rights reserved.

Characteristics of Crushing Energy and Fractal of Magnetite Ore under Uniaxial Compression

NASA Astrophysics Data System (ADS)

Gao, F.; Gan, D. Q.; Zhang, Y. B.

2018-03-01

The crushing mechanism of magnetite ore is a critical theoretical problem on the controlling of energy dissipation and machine crushing quality in ore material processing. Uniaxial crushing tests were carried out to research the deformation mechanism and the laws of the energy evolution, based on which the crushing mechanism of magnetite ore was explored. The compaction stage and plasticity and damage stage are two main compression deformation stages, the main transitional forms from inner damage to fracture are plastic deformation and stick-slip. In the process of crushing, plasticity and damage stage is the key link on energy absorption for that the specimen tends to saturate energy state approaching to the peak stress. The characteristics of specimen deformation and energy dissipation can synthetically reply the state of existed defects inner raw magnetite ore and the damage process during loading period. The fast releasing of elastic energy and the work done by the press machine commonly make raw magnetite ore thoroughly broken after peak stress. Magnetite ore fragments have statistical self-similarity and size threshold of fractal characteristics under uniaxial squeezing crushing. The larger ratio of releasable elastic energy and dissipation energy and the faster energy change rate is the better fractal properties and crushing quality magnetite ore has under uniaxial crushing.

Long-Term Planning for Open Pits for Mining Sulphide-Oxide Ores in Order to Achieve Maximum Profit

NASA Astrophysics Data System (ADS)

Kržanović, Daniel; Conić, Vesna; Stevanović, Dejan; Kolonja, Božo; Vaduvesković, Jovan

2017-12-01

Profitable exploitation of mineralised material from the earth's crust is a complex and difficult task that depends on a comprehensive planning process. Answering the question of how to plan production depends on the geometry of the deposit, as well as the concentration, distribution, and type of minerals in it. The complex nature of mineral deposits largely determines the method of exploitation and profitability of mining operations. In addition to unit operating costs and metal prices, the optimal recovery of and achievement of maximum profit from deposits of sulphide-oxide ores also depend, to a significant extent, on the level of technological recovery achieved in the ore processing procedure. Therefore, in defining a long-term development strategy for open pits, special attention must be paid to the selection of an optimal procedure for ore processing in order to achieve the main objective: maximising the Net Present Value (NPV). The effect of using two different processes, flotation processing and hydrometallurgical methods (bioleaching acid leaching), on determining the ultimate pit is shown in the case of the Kraku Bugaresku-Cementacija sulphide-oxide ore deposit in eastern Serbia. Analysis shows that the application of hydrometallurgical methods of processing sulphide-oxide ore achieved an increase in NPV of 20.42%.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2005-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not breakdown during processing. However, for many important metal extraction processes there are no binders known that will workmore » satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of many facilities see large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2004-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. A primary example of this is copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process. As a result, operators of acidic heap-leach facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of other agglomeration applications, particularly advanced primary ironmaking.« less

Experimenting With Ore: Creating the Taconite Process; flow chart of ...

Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

Experimenting With Ore: Creating the Taconite Process; flow chart of process - Mines Experiment Station, University of Minnesota, Twin Cities Campus, 56 East River Road, Minneapolis, Hennepin County, MN

Childhood lead poisoning associated with gold ore processing: a village-level investigation-Zamfara State, Nigeria, October-November 2010.

PubMed

Lo, Yi-Chun; Dooyema, Carrie A; Neri, Antonio; Durant, James; Jefferies, Taran; Medina-Marino, Andrew; de Ravello, Lori; Thoroughman, Douglas; Davis, Lora; Dankoli, Raymond S; Samson, Matthias Y; Ibrahim, Luka M; Okechukwu, Ossai; Umar-Tsafe, Nasir T; Dama, Alhassan H; Brown, Mary Jean

2012-10-01

During May-June 2010, a childhood lead poisoning outbreak related to gold ore processing was confirmed in two villages in Zamfara State, Nigeria. During June-September of that year, villages with suspected or confirmed childhood lead poisoning continued to be identified in Zamfara State. We investigated the extent of childhood lead poisoning [≥ 1 child with a blood lead level (BLL) ≥ 10 µg/dL] and lead contamination (≥ 1 soil/dust sample with a lead level > 400 parts per million) among villages in Zamfara State and identified villages that should be prioritized for urgent interventions. We used chain-referral sampling to identify villages of interest, defined as villages suspected of participation in gold ore processing during the previous 12 months. We interviewed villagers, determined BLLs among children < 5 years of age, and analyzed soil/dust from public areas and homes for lead. We identified 131 villages of interest and visited 74 (56%) villages in three local government areas. Fifty-four (77%) of 70 villages that completed the survey reported gold ore processing. Ore-processing villages were more likely to have ≥ 1 child < 5 years of age with lead poisoning (68% vs. 50%, p = 0.17) or death following convulsions (74% vs. 44%, p = 0.02). Soil/dust contamination and BLL ≥ 45 µg/dL were identified in ore-processing villages only [50% (p < 0.001) and 15% (p = 0.22), respectively]. The odds of childhood lead poisoning or lead contamination was 3.5 times as high in ore-processing villages than the other villages (95% confidence interval: 1.1, 11.3). Childhood lead poisoning and lead contamination were widespread in surveyed areas, particularly among villages that had processed ore recently. Urgent interventions are required to reduce lead exposure, morbidity, and mortality in affected communities.

Childhood Lead Poisoning Associated with Gold Ore Processing: a Village-Level Investigation—Zamfara State, Nigeria, October–November 2010

PubMed Central

Lo, Yi-Chun; Dooyema, Carrie A.; Neri, Antonio; Durant, James; Jefferies, Taran; Medina-Marino, Andrew; de Ravello, Lori; Thoroughman, Douglas; Davis, Lora; Dankoli, Raymond S.; Samson, Matthias Y.; Ibrahim, Luka M.; Okechukwu, Ossai; Umar-Tsafe, Nasir T.; Dama, Alhassan H.

2012-01-01

Background: During May–June 2010, a childhood lead poisoning outbreak related to gold ore processing was confirmed in two villages in Zamfara State, Nigeria. During June–September of that year, villages with suspected or confirmed childhood lead poisoning continued to be identified in Zamfara State. Objectives: We investigated the extent of childhood lead poisoning [≥ 1 child with a blood lead level (BLL) ≥ 10 µg/dL] and lead contamination (≥ 1 soil/dust sample with a lead level > 400 parts per million) among villages in Zamfara State and identified villages that should be prioritized for urgent interventions. Methods: We used chain-referral sampling to identify villages of interest, defined as villages suspected of participation in gold ore processing during the previous 12 months. We interviewed villagers, determined BLLs among children < 5 years of age, and analyzed soil/dust from public areas and homes for lead. Results: We identified 131 villages of interest and visited 74 (56%) villages in three local government areas. Fifty-four (77%) of 70 villages that completed the survey reported gold ore processing. Ore-processing villages were more likely to have ≥ 1 child < 5 years of age with lead poisoning (68% vs. 50%, p = 0.17) or death following convulsions (74% vs. 44%, p = 0.02). Soil/dust contamination and BLL ≥ 45 µg/dL were identified in ore-processing villages only [50% (p < 0.001) and 15% (p = 0.22), respectively]. The odds of childhood lead poisoning or lead contamination was 3.5 times as high in ore-processing villages than the other villages (95% confidence interval: 1.1, 11.3). Conclusion: Childhood lead poisoning and lead contamination were widespread in surveyed areas, particularly among villages that had processed ore recently. Urgent interventions are required to reduce lead exposure, morbidity, and mortality in affected communities. PMID:22766030

Face format at encoding affects the other-race effect in face memory.

PubMed

Zhao, Mintao; Hayward, William G; Bülthoff, Isabelle

2014-08-07

Memory of own-race faces is generally better than memory of other-races faces. This other-race effect (ORE) in face memory has been attributed to differences in contact, holistic processing, and motivation to individuate faces. Since most studies demonstrate the ORE with participants learning and recognizing static, single-view faces, it remains unclear whether the ORE can be generalized to different face learning conditions. Using an old/new recognition task, we tested whether face format at encoding modulates the ORE. The results showed a significant ORE when participants learned static, single-view faces (Experiment 1). In contrast, the ORE disappeared when participants learned rigidly moving faces (Experiment 2). Moreover, learning faces displayed from four discrete views produced the same results as learning rigidly moving faces (Experiment 3). Contact with other-race faces was correlated with the magnitude of the ORE. Nonetheless, the absence of the ORE in Experiments 2 and 3 cannot be readily explained by either more frequent contact with other-race faces or stronger motivation to individuate them. These results demonstrate that the ORE is sensitive to face format at encoding, supporting the hypothesis that relative involvement of holistic and featural processing at encoding mediates the ORE observed in face memory. © 2014 ARVO.

Bioleaching of manganese by Aspergillus sp. isolated from mining deposits.

PubMed

Mohanty, Sansuta; Ghosh, Shreya; Nayak, Sanghamitra; Das, Alok Prasad

2017-04-01

A comprehensive study on fungus assisted bioleaching of manganese (Mn) was carried out to demonstrate Mn solubilization of collected low grade ore from mining deposits of Sanindipur, Odisha, India. A native fungal strain MSF 5 was isolated and identified as Aspergillus sp. by Inter Transcribed Spacer (ITS) sequencing. The identified strain revealed an elevated tolerance ability to Mn under varying optimizing conditions like initial pH (2, 3, 4, 5, 6, 7), carbon sources (dextrose, sucrose, fructose and glucose) and pulp density (2%, 3%, 4%, 5% and 6%). Bioleaching studies carried out under optimized conditions of 2% pulp density of Mn ore at pH 6, temperature 37 °C and carbon dosage (dextrose) resulted with 79% Mn recovery from the ore sample within 20 days. SEM-EDX characterization of the ore sample and leach residue was carried out and the micrographs demonstrated porous and coagulated precipitates scattered across the matrix. The corresponding approach of FTIR analysis regulating the Mn oxide formation shows a distinctive peak of mycelium cells with and without treated Mn, resulting with generalized vibrations like MnO x stretching and CH 2 stretch. Thus, our investigation endeavors' the considerate possible mechanism involved in fungal surface cells onto Mn ore illustrating an alteration in cellular Mn interaction. Copyright © 2016 Elsevier Ltd. All rights reserved.

Nanocrystalline Iron-Ore-Based Catalysts for Fischer-Tropsch Synthesis.

PubMed

Yong, Seok; Park, Ji Chan; Lee, Ho-Tae; Yang, Jung-Il; Hong, SungJun; Jung, Heon; Chun, Dong Hyun

2016-02-01

Nanocrystalline iron ore particles were fabricated by a wet-milling process using an Ultra Apex Mill, after which they were used as raw materials of iron-based catalysts for low-temperature Fischer-Tropsch synthesis (FTS) below 280 degrees C, which usually requires catalysts with a high surface area, a large pore volume, and a small crystallite size. The wet-milling process using the Ultra Apex Mill effectively destroyed the initial crystallite structure of the natural iron ores of several tens to hundreds of nanometers in size, resulting in the generation of nanocrystalline iron ore particles with a high surface area and a large pore volume. The iron-ore-based catalysts prepared from the nanocrystalline iron ore particles effectively catalyzed the low-temperature FTS, displaying a high CO conversion (about 90%) and good C5+ hydrocarbon productivity (about 0.22 g/g(cat)(-h)). This demonstrates the feasibility of using the iron-ore-based catalysts as inexpensive and disposable catalysts for the low-temperature FTS.

Remediation of hexavalent chromium contamination in chromite ore processing residue by sodium dithionite and sodium phosphate addition and its mechanism.

PubMed

Li, Yunyi; Cundy, Andrew B; Feng, Jingxuan; Fu, Hang; Wang, Xiaojing; Liu, Yangsheng

2017-05-01

Large amounts of chromite ore processing residue (COPR) wastes have been deposited in many countries worldwide, generating significant contamination issues from the highly mobile and toxic hexavalent chromium species (Cr(VI)). In this study, sodium dithionite (Na 2 S 2 O 4 ) was used to reduce Cr(VI) to Cr(III) in COPR containing high available Fe, and then sodium phosphate (Na 3 PO 4 ) was utilized to further immobilize Cr(III), via a two-step procedure (TSP). Remediation and immobilization processes and mechanisms were systematically investigated using batch experiments, sequential extraction studies, X-ray diffraction (XRD) and X-ray Photoelectron Spectroscopy (XPS). Results showed that Na 2 S 2 O 4 effectively reduced Cr(VI) to Cr(III), catalyzed by Fe(III). The subsequent addition of Na 3 PO 4 further immobilized Cr(III) by the formation of crystalline CrPO 4 ·6H 2 O. However, addition of Na 3 PO 4 simultaneously with Na 2 S 2 O 4 (via a one-step procedure, OSP) impeded Cr(VI) reduction due to the competitive reaction of Na 3 PO 4 and Na 2 S 2 O 4 with Fe(III). Thus, the remediation efficiency of the TSP was much higher than the corresponding OSP. Using an optimal dosage in the two-step procedure (Na 2 S 2 O 4 at a dosage of 12× the stoichiometric requirement for 15 days, and then Na 3 PO 4 in a molar ratio (i.e. Na 3 PO 4 : initial Cr(VI)) of 4:1 for another 15 days), the total dissolved Cr in the leachate determined via Toxicity Characteristic Leaching Procedure (TCLP Cr) testing of our samples was reduced to 3.8 mg/L (from an initial TCLP Cr of 112.2 mg/L, i.e. at >96% efficiency). Copyright © 2017 Elsevier Ltd. All rights reserved.

Blasting preparation for selective mining of complex structured ore deposition

NASA Astrophysics Data System (ADS)

Marinin, M. A.; Dolzhikov, V. V.

2017-10-01

Technological features of ore mining in the open pit development for processing of complex structured ore deposit of steeply falling occurrence have been considered. The technological schemes of ore bodies mining under different conditions of occurrence, consistency and capacity have been considered and offered in the paper. These technologies permit to reduce losses and dilution, but to increase the completeness and quality of mined ore. A method of subsequent selective excavation of ore bodies has been proposed. The method is based on the complex use of buffer-blasting technology for the muck mass and the principle of trim blasting at ore-rock junctions.

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-07-07

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Bacterio-electric leaching of metals

DOEpatents

Lazaroff, Norman; Dugan, Patrick R.

1992-01-01

The separation of cationic materials from an ore body is assisted by the application of an electric potential, and resulting current, to the ore body, in association with iron or sulphur oxidizing bacteria. The combined process induces migration of cationic metals to a cathode suspended within the ore body so that the cationic metal can be preferentially separated from the ore body.

Beneficiation and leaching study of a muti-Au carrier and low grade refractory gold ore

NASA Astrophysics Data System (ADS)

Li, W. J.; Song, Y. S.; Chen, Y.; Cai, L. L.; Zhou, G. Y.

2017-09-01

Detailed mineralogy and beneficiation and leaching study of a muti-Au carrier, low grade refractory gold ore from a beneficiation plant in Henan Province, China, was investigated. Mineral liberation analysis, scanning electron microscopy, element phase analysis and etc. by a mineral liberation analyser were used for mineralogical characterization study of this ore. The present work describes an experimental study on the effect of traditional parameters (such as grinding fineness and reagent regimes), middling processing method and flowsheet construction on the total recovery and the assay of the floatation concentrate. Two-step floatation and part of middling combined to the floatation tailing for gold leaching process resulted in high gold grade (g.t-1) and gold recovery (%) for this refractory gold ore. This process opens the possibilities of maximizing Au grade and recoveries in a muti-Au carrier and low grade refractory gold ore where low recoveries are common.

Fractionation study in bioleached metallurgy wastes using six-step sequential extraction.

PubMed

Krasnodebska-Ostrega, Beata; Pałdyna, Joanna; Kowalska, Joanna; Jedynak, Łukasz; Golimowski, Jerzy

2009-08-15

The stored metallurgy wastes contain residues from ore processing operations that are characterized by relatively high concentrations of heavy metals. The bioleaching process makes use of bacteria to recover elements from industrial wastes and to decrease potential risk of environmental contamination. Wastes were treated by solutions containing bacteria. In this work, the optimized six-stage sequential extraction procedure was applied for the fractionation of Ni, Cr, Fe, Mn, Cu and Zn in iron-nickel metallurgy wastes deposited in Southern Poland (Szklary). Fractionation and total concentrations of elements in wastes before and after various bioleaching treatments were studied. Analyses of the extracts were performed by ICP-MS and FAAS. To achieve the most effective bioleaching of Zn, Cr, Ni, Cu, Mn, Fe the usage of both autotrophic and heterotrophic bacteria in sequence, combined with flushing of the residue after bioleaching is required. 80-100% of total metal concentrations were mobilized after the proposed treatment. Wastes treated according to this procedure could be deposited without any risk of environmental contamination and additionally the metals could be recovered for industrial purposes.

NOVEL BINDERS AND METHODS FOR AGGLOMERATION OF ORE

DOE Office of Scientific and Technical Information (OSTI.GOV)

S.K. Kawatra; T.C. Eisele; J.A. Gurtler

2004-04-01

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking.« less

Tourmaline as a recorder of ore-forming processes

USGS Publications Warehouse

Slack, John F.; Trumbull, Robert B.

2011-01-01

Tourmaline occurs in diverse types of hydrothermal mineral deposits and can be used to constrain the nature and evolution of ore-forming fl uids. Because of its broad range in composition and retention of chemical and isotopic signatures, tourmaline may be the only robust recorder of original mineralizing processes in some deposits. Microtextures and in situ analysis of compositional and isotopic variations in ore-related tourmaline provide valuable insights into hydrothermal systems in seafl oor, sedimentary, magmatic, and metamorphic environments. Deciphering the hydrothermal record in tourmaline also holds promise for aiding exploration programs in the search for new ore deposits.

Sewage sludge as a fuel and raw material for phosphorus recovery: Combined process of gasification and P extraction.

PubMed

Gorazda, K; Tarko, B; Werle, S; Wzorek, Z

2018-03-01

Increasing problems associated with sewage sludge disposal are observed nowadays. As the thermal conversion of sewage sludge (combustion, co-combustion, gasification and pyrolysis) appears to be the most promising alternative for its management, the solid residues left after gasification were examined. The present study evaluates the potential of this waste as an alternative phosphorus source in the context of phosphorus recovery. The obtained solid gasification residues were characterised (chemical and phase composition, thermal properties, surface properties and technological parameters used for phosphorus raw materials) and compared to commercial phosphate raw materials. It was revealed that gasification residue is a valuable source of phosphorus and microelements, comparable to sewage sludge ash (SSA) considered nowadays as secondary phosphorus raw materials. Chemical properties as well as technological parameters characteristic for natural phosphate ores are different. Solid gasification residue was leached with mineral acids (phosphoric and nitric) according to the patented method of phosphorus recovery - PolFerAsh, developed by Cracow University of Technology. It was revealed that phosphorus can be selectively leached from solid gasification residue with high efficiency (73-82%); moreover, most of the iron and heavy metals stay in the solid phase due to the low concentration of acids and proper solid to liquid phase ratio. The obtained leachates are valuable products that can be considered for the production of fertilisers. Combining the gasification process with nutrient recovery provides the opportunity for more environmentally efficient technologies driven by sustainable development rules. Copyright © 2017 Elsevier Ltd. All rights reserved.

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2011 CFR

2011-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2013 CFR

2013-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2012 CFR

2012-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2010 CFR

2010-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

40 CFR 63.9580 - What is the purpose of this subpart?

Code of Federal Regulations, 2014 CFR

2014-07-01

... (CONTINUED) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing What This... standards for hazardous air pollutants (NESHAP) for taconite iron ore processing. This subpart also...

Technical Report on the Behavior of Trace Elements, Stable Isotopes, and Radiogenic Isotopes During the Processing of Uranium Ore to Uranium Ore Concentrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

Marks, N. E.; Borg, L. E.; Eppich, G. R.

2015-07-09

The goals of this SP-1 effort were to understand how isotopic and elemental signatures behave during mining, milling, and concentration and to identify analytes that might preserve geologic signatures of the protolith ores. The impurities that are preserved through the concentration process could provide useful forensic signatures and perhaps prove diagnostic of sample origin.

Se Isotopes as groundwater redox indicators: Detecting natural attenuation of Se at an in situ recovery U mine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Anirban, Basu; Schilling, Kathrin; Brown, Shaun T.

One of the major ecological concerns associated with the in situ recovery (ISR) of uranium (U) is the environmental release of soluble, toxic selenium (Se) oxyanions generated by mining. Post-mining natural attenuation by the residual reductants in the ore body and reduced down-gradient sediments should mitigate the risk of Se contamination in groundwater. Here in this work, we investigate the Se concentrations and Se isotope systematics of groundwater and of U ore bearing sediments from an ISR site at Rosita, TX, USA. Our results show that selenate (Se(VI)) is the dominant Se species in Rosita groundwater, and while several up-gradientmore » wells have elevated Se(VI), the majority of the ore zone and down-gradient wells have little or no Se oxyanions. In addition, the δ 82SeVI of Rosita groundwater is generally elevated relative to the U ore up to +6.14‰, with the most enriched values observed in the ore-zone wells. Increasing δ 82Se with decreasing Se(VI) conforms to a Rayleigh type distillation model with an ε of $-$2.25‰ ± 0.61‰, suggesting natural Se(VI) reduction occurring along the hydraulic gradient at the Rosita ISR site. Moreover, our results show that Se isotopes are excellent sensors for detecting and monitoring post-mining natural attenuation of Se oxyanions at ISR sites.« less

Se Isotopes as groundwater redox indicators: Detecting natural attenuation of Se at an in situ recovery U mine

DOE PAGES

Anirban, Basu; Schilling, Kathrin; Brown, Shaun T.; ...

2016-08-22

One of the major ecological concerns associated with the in situ recovery (ISR) of uranium (U) is the environmental release of soluble, toxic selenium (Se) oxyanions generated by mining. Post-mining natural attenuation by the residual reductants in the ore body and reduced down-gradient sediments should mitigate the risk of Se contamination in groundwater. Here in this work, we investigate the Se concentrations and Se isotope systematics of groundwater and of U ore bearing sediments from an ISR site at Rosita, TX, USA. Our results show that selenate (Se(VI)) is the dominant Se species in Rosita groundwater, and while several up-gradientmore » wells have elevated Se(VI), the majority of the ore zone and down-gradient wells have little or no Se oxyanions. In addition, the δ 82SeVI of Rosita groundwater is generally elevated relative to the U ore up to +6.14‰, with the most enriched values observed in the ore-zone wells. Increasing δ 82Se with decreasing Se(VI) conforms to a Rayleigh type distillation model with an ε of $-$2.25‰ ± 0.61‰, suggesting natural Se(VI) reduction occurring along the hydraulic gradient at the Rosita ISR site. Moreover, our results show that Se isotopes are excellent sensors for detecting and monitoring post-mining natural attenuation of Se oxyanions at ISR sites.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-03-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; J. A. Gurtler

2005-09-30

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily at a reasonable cost. A primary example of this is copper heap leaching, where there are no binders currently encountered in this acidic environment process. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching. The active involvement of our industrial partners will help to ensure rapid commercialization of any agglomeration technologies developed by this project.« less

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-12-31

Many metal extraction operations, such as leaching of copper, leaching of precious metals, and reduction of metal oxides to metal in high-temperature furnaces, require agglomeration of ore to ensure that reactive liquids or gases are evenly distributed throughout the ore being processed. Agglomeration of ore into coarse, porous masses achieves this even distribution of fluids by preventing fine particles from migrating and clogging the spaces and channels between the larger ore particles. Binders are critically necessary to produce agglomerates that will not break down during processing. However, for many important metal extraction processes there are no binders known that willmore » work satisfactorily. Primary examples of this are copper heap leaching, where there are no binders that will work in the acidic environment encountered in this process, and advanced ironmaking processes, where binders must function satisfactorily over an extraordinarily large range of temperatures (from room temperature up to over 1200 C). As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. The large quantities of ore that must be handled in metal extraction processes also means that the binder must be inexpensive and useful at low dosages to be economical. The acid-resistant binders and agglomeration procedures developed in this project will also be adapted for use in improving the energy efficiency and performance of a broad range of mineral agglomeration applications, particularly heap leaching and advanced primary ironmaking. This project has identified several acid-resistant binders and agglomeration procedures that can be used for improving the energy efficiency of heap leaching, by preventing the ''ponding'' and ''channeling'' effects that currently cause reduced recovery and extended leaching cycle times. Methods have also been developed for iron ore processing which are intended to improve the performance of pellet binders, and have directly saved energy by increasing filtration rates of the pelletization feed by as much as 23%.« less

Characterization of Sumbawa manganese ore and recovery of manganese sulfate as leaching products

NASA Astrophysics Data System (ADS)

Kusumaningrum, Retno; Rahmani, Siti Astari; Widayatno, Wahyu Bambang; Wismogroho, Agus Sukarto; Nugroho, Dwi Wahyu; Maulana, Syahrizal; Rochman, Nurul Taufiqu; Amal, M. Ikhlasul

2018-05-01

The aims of this research were to study the leaching process of manganese ore which originated from Sumbawa, Indonesia and its characterization. A high grade Indonesian manganese ore from Sumbawa, West of Nusa Tenggara was characterized by X-Ray Fluorescence (XRF). The result showed composition of 78.8 % Mn, 17.77% Fe and the rest were trace elements such as Si, Co, Ti, Zn, V and Zr contents. X-Ray Diffraction analysis showed that the manganese ore was consisted of pyrolusite (MnO2), rhodonite (MnSiO3), rhodochrosite (MnCO3) and hematite (Fe2O3). Manganese ore was also analyzed by thermal analysis to observe their thermal decomposition character. In this study, sulphuric acid (H2SO4, 6 M) was deployed as leaching agent. The leaching process was performed at 90 °C for two hours with the addition of NH4OH to control pH. Recovery percentage of leaching process yielded of 87 % Mn extracted. The crystallization process result at heating temperature of 200 °C was confirmed by XRD as manganese sulfate.

Genesis of iron-apatite ores in Posht-e-Badam Block (Central Iran) using REE geochemistry

NASA Astrophysics Data System (ADS)

Mokhtari, Mir Ali Asghar; Zadeh, Ghader Hossein; Emami, Mohamad Hashem

2013-06-01

Rare earth elements in apatites of different ore types show characteristic patterns which are related to different modes of formation of the ores. Most of the apatite-bearing iron ores are associated with alkaline magmas with LREE/HREE fractionation varying from moderate to steep. Iron-apatite deposits in Posht-e-Badam Block (Central Iran) have a high concentration of REE (more than 1000 ppm up to 2.5%), and show a strong LREE/HREE ratio with a pronounced negative Eu anomaly. This REE pattern is typical of magmatic apatite and quiet distinct from sedimentary apatites (phosphorites) which have a low REE contents and Ce negative anomalies. On the other hand, they are comparable to the REE patterns of apatites in Kiruna-type iron ores in different parts of the world. The REE patterns of apatites, iron-apatite ores and iron ores are similar and only have different REE contents. This similarity indicates a genetic relation for these rocks. Most of the iron-apatite deposits in Central Iran have similar REE patterns too, which in turn show a genetic relation for all of these deposits. This similarity indicates a similar origin and processes in their genesis. There are some small intrusions around some of the iron-apatite deposits that are petrographically identified as syenite and gabbro. These intrusions also have REE patterns similar to that of iron-apatite ores. This demonstrates a genetic relation between these intrusions and iron-apatite ores. The REE patterns of apatites in different deposits of Posht-e-Badam Block iron-apatite ores show an affinity to alkaline to sub-alkaline magmas and rifting environment. The alkaline host rocks of Central Iran iron-apatite ores are clearly related to an extensional setting where rifting was important (SSE-NNW fault lines). A probable source for this large scale ore forming processes is relatively low partial melting of mantle rocks. The ores have originated by magmatic differentiation as a late phase in the volcanic cycle forming sub-surface injections or surface flows. These ores have formed during magmatism as immiscible liquids (silicate and Fe-P-rich magmatic liquids) which separated from strongly differentiated magmas aided by a large volatile and alkali element content. Separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits. We proposed that the separation of an iron oxide melt and the ensuing hydrothermal processes dominated by alkali metasomatism were both involved to different degrees in the formation of Posht-e-Badam Block iron-apatite deposits.

Small-scale studies of roasted ore waste reveal extreme ranges of stable mercury isotope signatures

NASA Astrophysics Data System (ADS)

Smith, Robin S.; Wiederhold, Jan G.; Jew, Adam D.; Brown, Gordon E.; Bourdon, Bernard; Kretzschmar, Ruben

2014-07-01

Active and closed Hg mines are significant sources of Hg contamination to the environment, mainly due to large volumes of mine waste material disposed of on-site. The application of Hg isotopes as source tracer from such contaminated sites requires knowledge of the Hg isotope signatures of different materials potentially released to the environment. Previous work has shown that calcine, the waste residue of the on-site ore roasting process, can exhibit distinct Hg isotope signatures compared with the primary ore. Here, we report results from a detailed small-scale study of Hg isotope variations in calcine collected from the closed New Idria Hg mine, San Benito County, CA, USA. The calcine samples exhibited different internal layering features which were investigated using optical microscopy, micro X-ray fluorescence, micro X-ray absorption spectroscopy (μ-XAS), and stable Hg isotope analysis. Significant Fe, S, and Hg concentration gradients were found across the different internal layers. Isotopic analyses revealed an extreme variation with pronounced isotopic gradients across the internal layered features. Overall, δ202Hg (±0.10‰, 2 SD) describing mass-dependent fractionation (MDF) ranged from -5.96 to 14.49‰, which is by far the largest range of δ202Hg values reported for any environmental sample. In addition, Δ199Hg (±0.06‰, 2 SD) describing mass-independent fractionation (MIF) ranged from -0.17 to 0.21‰. The μ-XAS analyses suggested that cinnabar and metacinnabar are the dominant Hg-bearing phases in the calcine. Our results demonstrate that the incomplete roasting of HgS ores in Hg mines can cause extreme mass-dependent Hg isotope fractionations at the scale of individual calcine pieces with enrichments in both light and heavy Hg isotopes relative to the primary ore signatures. This finding has important implications for the application of Hg isotopes as potential source tracers for Hg released to the environment from closed Hg mines and highlights the need for detailed source signature identification.

Iron isotope fractionation during hydrothermal ore deposition and alteration

NASA Astrophysics Data System (ADS)

Markl, Gregor; von Blanckenburg, Friedhelm; Wagner, Thomas

2006-06-01

Iron isotopes fractionate during hydrothermal processes. Therefore, the Fe isotope composition of ore-forming minerals characterizes either iron sources or fluid histories. The former potentially serves to distinguish between sedimentary, magmatic or metamorphic iron sources, and the latter allows the reconstruction of precipitation and redox processes. These processes take place during ore formation or alteration. The aim of this contribution is to investigate the suitability of this new isotope method as a probe of ore-related processes. For this purpose 51 samples of iron ores and iron mineral separates from the Schwarzwald region, southwest Germany, were analyzed for their iron isotope composition using multicollector ICP-MS. Further, the ore-forming and ore-altering processes were quantitatively modeled using reaction path calculations. The Schwarzwald mining district hosts mineralizations that formed discontinuously over almost 300 Ma of hydrothermal activity. Primary hematite, siderite and sulfides formed from mixing of meteoric fluids with deeper crustal brines. Later, these minerals were partly dissolved and oxidized, and secondary hematite, goethite and iron arsenates were precipitated. Two types of alteration products formed: (1) primary and high-temperature secondary Fe minerals formed between 120 and 300 °C, and (2) low-temperature secondary Fe minerals formed under supergene conditions (<100 °C). Measured iron isotope compositions are variable and cover a range in δ56Fe between -2.3‰ and +1.3‰. Primary hematite ( δ56Fe: -0.5‰ to +0.5‰) precipitated by mixing oxidizing surface waters with a hydrothermal fluid that contained moderately light Fe ( δ56Fe: -0.5‰) leached from the crystalline basement. Occasional input of CO 2-rich waters resulted in precipitation of isotopically light siderite ( δ56Fe: -1.4 to -0.7‰). The difference between hematite and siderite is compatible with published Fe isotope fractionation factors. The observed range in isotopic compositions can be accounted for by variable fractions of Fe precipitating from the fluid. Therefore, both fluid processes and mass balance can be inferred from Fe isotopes. Supergene weathering of siderite by oxidizing surface waters led to replacement of isotopically light primary siderite by similarly light secondary hematite and goethite, respectively. Because this replacement entails quantitative transfer of iron from precursor mineral to product, no significant isotope fractionation is produced. Hence, Fe isotopes potentially serve to identify precursors in ore alteration products. Goethites from oolitic sedimentary iron ores were also analyzed. Their compositional range appears to indicate oxidative precipitation from relatively uniform Fe dissolved in coastal water. This comprehensive iron isotope study illustrates the potential of the new technique in deciphering ore formation and alteration processes. Isotope ratios are strongly dependent on and highly characteristic of fluid and precipitation histories. Therefore, they are less suitable to provide information on Fe sources. However, it will be possible to unravel the physico-chemical processes leading to the formation, dissolution and redeposition of ores in great detail.

Rock Smelting of Copper Ores with Waste Heat Recovery

NASA Astrophysics Data System (ADS)

Norgate, Terry; Jahanshahi, Sharif; Haque, Nawshad

It is generally recognised that the grades of metallic ores are falling globally. This trend can be expected to increase the life cycle-based energy requirement for primary metal production due to the additional amount of material that must be handled and treated in the mining and mineral processing stages of the metal production life cycle. Rock (or whole ore) smelting has been suggested as a possible alternative processing route for low grade ores with a potentially lower energy intensity and environmental impact than traditional processing routes. In this processing route, the beneficiation stage is eliminated along with its associated energy consumption and greenhouse gas emissions, but this is partially offset by the need for more solid material to be handled and heated up to smelting temperatures. A life cycle assessment study was carried out to assess the potential energy and greenhouse gas benefits of a conceptual flowsheet of the rock smelting process, using copper ore as an example. Recovery and utilisation of waste heat in the slag (via dry slag granulation) and offgas streams from the smelting step was also included in the study, with the waste heat being utilised either for thermal applications or electricity generation.

PROCESS FOR THE RECOVERY OF METALS FROM HIGH-LIME CARNOTITE ORES

DOEpatents

Grinstead, R.R.

1959-01-20

A process is presented for recovering uranium values from a high-lime carnotite ore comprising contacting the ore dispersed in a finely divided state with a concentrated mineral acid, adding an industrial orgnnic solvent containing alkyl ontho or pyro phosphoric acids, alkyl phosphates or alkyl phosphonates so as to effect an organic phase into which the metal value is leached and then recovering the metal value from the organic phase.

Cr(VI) and Cr(III) removal from aqueous solution by raw and modified lignocellulosic materials: a review.

PubMed

Miretzky, P; Cirelli, A Fernandez

2010-08-15

In aqueous systems, chromium usually exists in both trivalent and hexavalent oxidation states, being Cr(VI) of particular importance and concern due to its great toxicity. Industrial sources of Cr(VI) are leather tanning, mining of chrome ore, production of steel and alloys, etc. The most common conventional method for Cr(VI) removal is reduction to Cr(III) at pH 2.0 and precipitation of Cr (OH)(3) with lime at pH 9-10. The disadvantage of precipitation is the disposal of the solid waste. Adsorption of Cr by different low cost materials seems to be a suitable choice for wastewater treatment. Many by-products of agriculture have proved to be suitable low cost adsorbents for Cr(VI) and Cr(III) removal from water. Lignocellulosic residues, which include both wood residues and agricultural residues, have adsorption capacity comparable to other natural sorbents, but they have the advantage of very low or no cost, great availability and simple operational process. This study is a review of the recent literature on the use of natural and modified lignocellulosic residues for Cr adsorption. The Cr maximum adsorption capacity and the adsorption mechanism under different experimental conditions are reported when possibly. Copyright 2010 Elsevier B.V. All rights reserved.

Effective Processing of the Iron Ores

NASA Astrophysics Data System (ADS)

Kuskov, Vadim; Kuskova, Yana; Udovitsky, Vladimir

2017-11-01

Effective technology for a complex wasteless processing of the iron ores has been designed and includes three main components (plats): comminution plant, briquette plant, pigment plant. The comminution is done per energy effective technology. Using of briquetting for ores clotting enables the costs cut and brings to a higher level of environmental safety of the process. Briquette formation can be done as a regular pressing, as an extrusion. Developed technology allows to produce high quality competitively products for metallurgy industry and red iron oxide pigments. The whole production line impacts the environment in a minimal manner.

Fact Sheet - Final Air Toxics Rule for Gold Mine Ore Processing and Production

EPA Pesticide Factsheets

Fact sheet summarizing main points of National Emissions Standards for Hazardous Air Pollutants for gold ore processing and production facilities, the seventh largest source of mercury air emission in the United States.

Use of X-Ray Fluorescence in a Laboratory for the Treatment of Uranium Ores; UTILISATION DE LA FLUORESCENCE DANS UN LABORATOIRE DE TRAITEMENTS DE MINERAIS D'URANIUM

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillet, H.

1960-01-01

A brief description is given of some aspects of the experience gained over a year during which x-ray fluorescence was used at the laberatory of the present Section Autonome d'Etudes, Recherches et Applications Chimiques of the Commissariat a l'Energie Atomique. A standard is tested daily to ensure reproducibility. The observations made during the months from Dec. 1958 to May 1959 are described. In acid leaching of uranium ores, the residues are analyzed by x-ray fluorescence directly in powder form. Fixation and elution of vanadium on ion-exchange resin were also studied. (auth)

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2011 CFR

2011-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... Molybdenum Ores Subcategory § 440.104 New source performance standards (NSPS). Except as provided in subpart... technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2010 CFR

2010-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... Molybdenum Ores Subcategory § 440.104 New source performance standards (NSPS). Except as provided in subpart... technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

Hydrometallurgical Extraction of Zinc and Copper A 57Fe-Mössbauer and XRD Approach

NASA Astrophysics Data System (ADS)

Mulaba-Bafubiandi, A. F.; Waanders, F. B.

2005-02-01

The most commonly used route in the hydrometallurgical extraction of zinc and copper from a sulphide ore is the concentrate roast leach electro winning process. In the present investigation a zinc copper ore from the Maranda mine, located in the Murchison Greenstone Belt, South Africa, containing sphalerite (ZnS) and chalcopyrite (CuFeS2), was studied. The 57Fe-Mössbauer spectrum of the concentrate yielded pyrite, chalcopyrite and clinochlore, consistent with XRD data. Optimal roasting conditions were found to be 900°C for 3 h and the calcine produced contained according to X-ray diffractometry equal amounts of franklinite (ZnFe2O4) and zinc oxide (ZnO) and half the amount of willemite (Zn2SiO4). The Mössbauer spectrum showed predominantly franklinite (59%), hematite (6%) and other Zn- or Cu-depleted ferrites (35%). The latter could not be detected by XRD analyses as peak overlapping with other species occurred. Leaching was done with HCl, H2SO4 and HNO3, to determine which process would result in maximum recovery of Zn and Cu. More than 80% of both were recovered by using either one of the three techniques. From the residue of the leaching, the Fe-compounds were precipitated and <1% of the Zn and Cu was not recovered.

Chemical analysis of extracting transition metal oxides from polymetallic ore by sulphate process

NASA Astrophysics Data System (ADS)

Enkh-Uyanga, Otgon-Uul; Munkhtsetseg, Baatar; Urangoo, Urtnasan; Tserendulam, Enkhtur; Agiimaa, Davaadorj

2017-06-01

In this research work we attempt to improve the purity of polymetallic ores in Mongolia whilst developing practical applications of its refinement processes and this paper presents the results of chemical research of extracting transition metal titanium oxides, ferrous oxide and rare earth oxides from polymetallic ore. Thereby, chemical and mineral analysis of polymetallic ore is carried out basis of responses to the support process at various degrees of water whereas transition metal sulphates solubility differ. As a result of sulphate and resulphurization process we have extracted anatase with 62.5 percent titanium dioxide and brookite mineral with 89.6 percent of titanium dioxide as well as mineral with 83.8 percent of ferrous oxide hematite and rare earth oxides with 57.6 percent of cerium oxide. These oxides are identified under various conditions in the thermal processing. The morphology structure and chemical content compound of the mineral has been verified as a result of the XRF, XRD, SEM-EDX analysis.

Chapter C: Hydrothermal Enrichment of Gallium in Zones of Advanced Argillic Alteration-Examples from the Paradise Peak and McDermitt Ore Deposits, Nevada

USGS Publications Warehouse

Rytuba, James J.; John, David A.; Foster, Andrea; Ludington, Steven D.; Kotlyar, Boris

2003-01-01

Gallium is produced as a byproduct from bauxite and zinc sulfide ores and rarely from primary Ga ores. High Ga contents (>60 ppm) can occur in zones of advanced argillic alteration consisting of alunite+kaolinite+quartz associated with quartz-alunite (high sulfidation Au-Ag) deposits. In a magmatic-hydrothermal environment, the zones of advanced argillic alteration associated with quartz-alunite (high sulfidation) Au-Ag deposits have the highest Ga contents (max 120 ppm). In these Au deposits, Ga is enriched in the zone of alunite+kaolinite alteration and depleted in the zone of quartz-rich alteration within acid-leached rocks. Peripheral zones of argillic alteration have Ga contents and Al/Ga ratios similar to those in unaltered volcanic rocks. The zones of advanced argillic alteration that formed in a steam-heated environment in association with hot-spring-type Hg-Au deposits are not Ga enriched, and residual silicified zones have very low Ga contents. The McDermitt Hg and Paradise Peak Au-Hg deposits, Nev., have zones of advanced argillic alteration that are Ga enriched. At the Paradise Peak Au-Hg deposits, Ga is enriched in the zone of alunite+jarosite alteration that formed in a magmatic-hydrothermal environment. Ga is depleted in the zone of opal+alunite alteration formed in a steam-heated environment, in residual silicified zones formed in a magmatic-hydrothermal environment, and in zones of supergene jarosite alteration. At the McDermitt Hg deposit, Ga is enriched in the zone of alunite+kaolinite alteration below the zone of adularia-quartz alteration that coincides with the Hg ore body. The spatial relation of Ga enrichment to alunite-kaolinite alteration suggests that formation in a magmatic-hydrothermal environment. X-ray-absorption spectra of Ga-enriched samples from the McDermitt Hg deposit are similar to that of gallium sulfate and support the association of Ga enrichment with alunite alteration.

Process and apparatus for solvent extraction of oil from oil-containing diatomite ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnofsky, G. B.

1980-12-16

A process for solvent extraction of oil from oil bearing diatomite ore and an apparatus for use therewith, wherein the ore is extracted by countercurrent decantation with a hydrocarbon solvent, solvent is recovered from the extract by multiple effect evaporation followed by stripping, and the spent diatomite is contacted with water to displace a major portion of the solvent therefrom, and solvent is recovered from the aqueous slurry of the spent diatomite by stripping with steam at superatmospheric pressure.

Microbial solubilization of phosphate

DOEpatents

Rogers, R.D.; Wolfram, J.H.

1993-10-26

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorus can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution. 6 figures.

Microbial solubilization of phosphate

DOEpatents

Rogers, Robert D.; Wolfram, James H.

1993-01-01

A process is provided for solubilizing phosphate from phosphate containing ore by treatment with microorganisms which comprises forming an aqueous mixture of phosphate ore, microorganisms operable for solubilizing phosphate from the phosphate ore and maintaining the aqueous mixture for a period of time and under conditions operable to effect the microbial solubilization process. An aqueous solution containing soluble phosphorous can be separated from the reacted mixture by precipitation, solvent extraction, selective membrane, exchange resin or gravity methods to recover phosphate from the aqueous solution.

Effects of reduction temperature to Ni and Fe content and the morphology of agglomerate of reduced laterite limonitic nickel ore by coal-bed method

NASA Astrophysics Data System (ADS)

Abdul, Fakhreza; Pintowantoro, Sungging; Kawigraha, Adji; Nursidiq, Ahlidin

2018-04-01

As the current drop of nickel sulfide ore on earth, the attention to nickel laterite ore processing was inscreased in order to fulfill the future nickel demand needs. This research aims to optimized the process of nickel laterite ore extraction using coal bed method. This research was conducted by reducing low grade nickel laterite ore (limonitic) with nickel content of 1.25 %. The reduction process was carried out using CO gas which formed by the reaction of coal and dolomite. The Briquette of nickel ore, coal, Na2SO4 mixtures incorporated in the crucible with bed, then reduced for 6 hours at the temperature of 1200 °C. 1400 °C, and 1400 °C. The result of the research shown that the highest increase of Ni content and Ni recovery value was in the reduction temperature of 1400 °C with the increase of 3.44 %, and the recovery value of Ni equal to 86.75 %. While the highest increase of Fe content and Fe recovery value, respectively, was in the reduction temperature of 1300 °C with the increase of 22.67 % and 1200 °C with Fe recovery value of 89.41 %.

New insight into the origin of manganese oxide ore deposits in the Appalachian Valley and Ridge of northeastern Tennessee and northern Virginia, USA

USGS Publications Warehouse

Carmichael, Sarah K.; Doctor, Daniel H.; Wilson, Crystal G.; Feierstein, Joshua; McAleer, Ryan J.

2017-01-01

Manganese oxide deposits have long been observed in association with carbonates within the Appalachian Mountains, but their origin has remained enigmatic for well over a century. Ore deposits of Mn oxides from several productive sites located in eastern Tennessee and northern Virginia display morphologies that include botryoidal and branching forms, massive nodules, breccia matrix cements, and fracture fills. The primary ore minerals include hollandite, cryptomelane, and romanèchite. Samples of Mn oxides from multiple localities in these regions were analyzed using electron microscopy, X-ray analysis, Fourier transform infrared spectroscopy, and trace and rare earth element (REE) geochemistry. The samples from eastern Tennessee have biological morphologies, contain residual biopolymers, and exhibit REE signatures that suggest the ore formation was due to supergene enrichment (likely coupled with microbial activity). In contrast, several northern Virginia ores hosted within quartz-sandstone breccias exhibit petrographic relations, mineral morphologies, and REE signatures indicating inorganic precipitation, and a likely hydrothermal origin with supergene overprinting. Nodular accumulations of Mn oxides within weathered alluvial deposits that occur close to breccia-hosted Mn deposits in Virginia show geochemical signatures that are distinct from the breccia matrices and appear to reflect remobilization of earlier-emplaced Mn and concentration within supergene traps. Based on the proximity of all of the productive ore deposits to mapped faults or other zones of deformation, we suggest that the primary source of all of the Mn may have been deep seated, and that Mn oxides with supergene and/or biological characteristics resulted from the local remobilization and concentration of this primary Mn.

Bio-mineralization and potential biogeochemical processes in bauxite deposits: genetic and ore quality significance

NASA Astrophysics Data System (ADS)

Laskou, Magdalini; Economou-Eliopoulos, Maria

2013-08-01

The Parnassos-Ghiona bauxite deposit in Greece of karst type is the 11th largest bauxite producer in the world. The mineralogical, major and trace-element contents and δ18O, δ12C, δ34S isotopic compositions of bauxite ores from this deposit and associated limestone provide valuable evidence for their origin and biogeochemical processes resulting in the beneficiation of low grade bauxite ores. The organic matter as thin coal layers, overlying the bauxite deposits, within limestone itself (negative δ12C isotopic values) and the negative δ34S values in sulfides within bauxite ores point to the existence of the appropriate circumstances for Fe bio-leaching and bio-mineralization. Furthermore, a consortium of microorganisms of varying morphological forms (filament-like and spherical to lenticular at an average size of 2 μm), either as fossils or presently living and producing enzymes, is a powerful factor to catalyze the redox reactions, expedite the rates of metal extraction and provide alternative pathways for metal leaching processes resulting in the beneficiation of bauxite ore.

The effect of smelting time and composition of palm kernel shell charcoal reductant toward extractive Pomalaa nickel laterite ore in mini electric arc furnace

NASA Astrophysics Data System (ADS)

Sihotang, Iqbal Huda; Supriyatna, Yayat Iman; Ismail, Ika; Sulistijono

2018-04-01

Indonesia is a country that is rich in natural resources. Being a third country which has a nickel laterite ore in the world after New Caledonia and Philippines. However, the processing of nickel laterite ore to increase its levels in Indonesia is still lacking. In the processing of nickel laterite ore into metal, it can be processed by pyrometallurgy method that typically use coal as a reductant. However, coal is a non-renewable energy and have high enough levels of pollution. One potentially replace is the biomass, that is a renewable energy. Palm kernel shell are biomass that can be used as a reductant because it has a fairly high fix carbon content. This research aims to make nickel laterite ores become metal using palm kernel shell charcoal as reductant in mini electric arc furnace. The result show that the best smelting time of this research is 60 minutes with the best composition of the reductant is 2,000 gram.

Kinetic study of nickel laterite reduction roasting by palm kernel shell charcoal

NASA Astrophysics Data System (ADS)

Sugiarto, E.; Putera, A. D. P.; Petrus, H. T. B. M.

2017-05-01

Demand to process nickel-bearing laterite ore increase as continuous depletion of high-grade nickel-bearing sulfide ore takes place. Due to its common nickel association with iron, processing nickel laterite ore into nickel pig iron (NPI) has been developed by some industries. However, to achieve satisfying nickel recoveries, the process needs massive high-grade metallurgical coke consumption. Concerning on the sustainability of coke supply and positive carbon emission, reduction of nickel laterite ore using biomass-based reductor was being studied.In this study, saprolitic nickel laterite ore was being reduced by palm kernel shell charcoal at several temperatures (800-1000 °C). Variation of biomass-laterite composition was also conducted to study the reduction mechanism. X-ray diffraction and gravimetry analysis were applied to justify the phenomenon and predict kinetic model of the reduction. Results of this study provide information that palm kernel shell charcoal has similar reducing result compared with the conventional method. Reduction, however, was carried out by carbon monoxide rather than solid carbon. Regarding kinetics, Ginstling-Brouhnstein kinetic model provides satisfying results to predict the reduction phenomenon.

75 FR 22469 - National Emission Standards for Hazardous Air Pollutants: Gold Mine Ore Processing and Production...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-28

... the lower TRI reporting threshold for mercury that went into effect about that time. Following this... roasting temperatures, which readily volatilize available mercury from the ore. The mercury concentrations... temperatures. Dry grinding of the ore prior to roasting is primarily a source of particulate matter (PM...

40 CFR 63.9621 - What test methods and other procedures must I use to demonstrate initial compliance with the...

Code of Federal Regulations, 2012 CFR

2012-07-01

...) National Emission Standards for Hazardous Air Pollutants: Taconite Iron Ore Processing Initial Compliance... section. (b) For each ore crushing and handling affected source and each finished pellet handling affected... each ore crushing and handling affected source and each finished pellet handling affected source, you...

75 FR 22838 - Notice of Availability of the Draft Environmental Impact Statement for the Genesis Project...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-04-30

... necessary haul roads and access roads, and process 60 million tons of gold-bearing ore. The proposed project... of mercury associated with processing the 60 million tons of ore; (3) The impacts of 12 additional...

A geochemical assessment of possible lunar ore formation

NASA Technical Reports Server (NTRS)

Haskin, Larry A.; Colson, Russell O.; Vaniman, David

1991-01-01

The Moon apparently formed without appreciable water or other relatively volatile materials. Interior concentrations of water or other volatile substances appear to be extremely low. On Earth, water is important to the genesis of nearly all types of ores. Thus, some have reasoned that only abundant elements would occur in ore concentrations. The definition and recognition of ores on the Moon challenge the imaginations and the terrestrial perceptions of ore bodies. Lunar ores included solar-wind soaked soils, which contain abundant but dilute H, C, N, and noble gases (including He-3). Oxygen must be mined; soils contain approximately 45 percent (wt). Mainstream processes of rock formation concentrated Si, Mg, Al, Fe, and Ca, and possibly Ti and Cr. The highland surface contains approximately 70 percent (wt) feldspar (mainly CaAl2Si2O8), which can be separated from some highland soils. Small fragments of dunite were collected; dunite may occur in walls and central peaks of some craters. Theoretical extensions of observations of lunar samples suggest that the Moon may have produced ores of trace elements. Some small fragments have trace-element concentrations 10(exp 4) times higher than the lunar average, indicating that effective geochemical separations occurred; processes included fractional crystallization, silicate immiscibility, vaporization and condensation, and sulfide metamorphism. Operations of these processes acting on indigenous materials and on meteoritic material in the regolith could have produced ores. Infalling carbonaceous meteorites and comets have added water and hydrocarbons that may have been cold-trapped. Vesicles in basalts, pyroclastic beads, and reported transient events suggest gag emission from the lunar interior; such gas might concentrate and transport rare elements. Large impacts may disperse ores or produce them through deposition of heat at depth and by vaporization and subsequent condensation. The main problem in assessing lunar resources is the ignorance about the largely unexplored Moon.

China's emergence as the world's leading iron-ore-consuming country

USGS Publications Warehouse

Kirk, W.S.

2004-01-01

China has become the leading iron ore consuming nation, and, based on recent steel production capacity increases and plans for more, its consumption will almost certainly to continue to grow. China's iron ore industry, however, faces a number of problems. China's iron ore is low-grade, expensive to process, and its mines are being depleted. For many Chinese steelmakers, particularly in the coastal regions, the delivered cost of domestic iron ore, is more than the delivered cost of foreign ore. Thus China's iron ore imports are expected to increase. As China's growth continues, it will almost certainly surpass Japan to become the leading iron ore importing country as well. Without China's increasing appetite for iron ore, the world iron ore market would be flat or declining. China's recent imports largely offset the slump in demand in North America and Europe. China is regarded by the iron ore industry as the growth sector for the next decade. Although Chinese imports are expected to continue their rapid increase and imports in other Asian countries are expected to continue growing, there appears to be enough greenfield and expansion projects to meet future demand for iron ore worldwide. Present suppliers of iron ore, Australia, Brazil, India, and South Africa, will probably be the chief beneficiaries of China's increasing consumption of iron ore. How long China can continue its extraordinary growth is the primary issue for the future of the iron ore industry. Based on the number and size of planned blast furnaces it appears that China's growth could continue for several more years. ?? 2004 Taylor and Francis.

Rock-magnetism and ore microscopy of the magnetite-apatite ore deposit from Cerro de Mercado, Mexico

NASA Astrophysics Data System (ADS)

Alva-Valdivia, L. M.; Goguitchaichvili, A.; Urrutia-Fucugauchi, J.; Caballero-Miranda, C.; Vivallo, W.

2001-03-01

Rock-magnetic and microscopic studies of the iron ores and associated igneous rocks in the Cerro de Mercado, Mexico, were carried out to determine the magnetic mineralogy and origin of natural remanent magnetization (NRM), related to the thermo-chemical processes due to hydrothermalism. Chemical remanent magnetization (CRM) seems to be present in most of investigated ore and wall rock samples, replacing completely or partially an original thermoremanent magnetization (TRM). Magnetite (or Ti-poor titanomagnetite) and hematite are commonly found in the ores. Although hematite may carry a stable CRM, no secondary components are detected above 580°, which probably attests that oxidation occurred soon enough after the extrusion and cooling of the ore-bearing magma. NRM polarities for most of the studied units are reverse. There is some scatter in the cleaned remanence directions of the ores, which may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient field during remanence acquisition by inhomogeneous internal fields within these strongly magnetic ore deposits. The microscopy study under reflected light shows that the magnetic carriers are mainly titanomagnetite, with significant amounts of ilmenite-hematite minerals, and goethite-limonite resulting from alteration processes. Magmatic titanomagnetites, which are found in igneous rocks, show trellis, sandwich, and composite textures, which are compatible with high temperature (deuteric) oxy-exsolution processes. Hydrothermal alteration in ore deposits is mainly indicated by martitization in oxide minerals. Grain sizes range from a few microns to >100 mm, and possible magnetic state from single to multidomain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and IRM (isothermal remanent magnetization) acquisition suggest a predominance of spinels as magnetic carriers, most probably titanomagnetites with low-Ti content. For quantitative modeling of the aeromagnetic anomalies, we used data on bulk susceptibility and natural remanent intensity for quantifying the relative contributions of induced and remanent magnetization components and allow a better control of the geometry of source bodies. The position and geometry of this magnetic source are shown as an ENE-striking tabular body, steeply inclined (75°) to the south.

BLENDING LOW ENRICHED URANIUM WITH DEPLETED URANIUM TO CREATE A SOURCE MATERIAL ORE THAT CAN BE PROCESSED FOR THE RECOVERY OF YELLOWCAKE AT A CONVENTIONAL URANIUM MILL

DOE Office of Scientific and Technical Information (OSTI.GOV)

Schutt, Stephen M.; Hochstein, Ron F.; Frydenlund, David C.

2003-02-27

Throughout the United States Department of Energy (DOE) complex, there are a number of streams of low enriched uranium (LEU) that contain various trace contaminants. These surplus nuclear materials require processing in order to meet commercial fuel cycle specifications. To date, they have not been designated as waste for disposal at the DOE's Nevada Test Site (NTS). Currently, with no commercial outlet available, the DOE is evaluating treatment and disposal as the ultimate disposition path for these materials. This paper will describe an innovative program that will provide a solution to DOE that will allow disposition of these materials atmore » a cost that will be competitive with treatment and disposal at the NTS, while at the same time recycling the material to recover a valuable energy resource (yellowcake) for reintroduction into the commercial nuclear fuel cycle. International Uranium (USA) Corporation (IUSA) and Nuclear Fuel Services, Inc. (NFS) have entered into a commercial relationship to pursue the development of this program. The program involves the design of a process and construction of a plant at NFS' site in Erwin, Tennessee, for the blending of contaminated LEU with depleted uranium (DU) to produce a uranium source material ore (USM Ore{trademark}). The USM Ore{trademark} will then be further processed at IUC's White Mesa Mill, located near Blanding, Utah, to produce conventional yellowcake, which can be delivered to conversion facilities, in the same manner as yellowcake that is produced from natural ores or other alternate feed materials. The primary source of feed for the business will be the significant sources of trace contaminated materials within the DOE complex. NFS has developed a dry blending process (DRYSM Process) to blend the surplus LEU material with DU at its Part 70 licensed facility, to produce USM Ore{trademark} with a U235 content within the range of U235 concentrations for source material. By reducing the U235 content to source material levels in this manner, the material will be suitable for processing at a conventional uranium mill under its existing Part 40 license to remove contaminants and enable the product to re-enter the commercial fuel cycle. The tailings from processing the USM Ore{trademark} at the mill will be permanently disposed of in the mill's tailings impoundment as 11e.(2) byproduct material. Blending LEU with DU to make a uranium source material ore that can be returned to the nuclear fuel cycle for processing to produce yellowcake, has never been accomplished before. This program will allow DOE to disposition its surplus LEU and DU in a cost effective manner, and at the same time provide for the recovery of valuable energy resources that would be lost through processing and disposal of the materials. This paper will discuss the nature of the surplus LEU and DU materials, the manner in which the LEU will be blended with DU to form a uranium source material ore, and the legal means by which this blending can be accomplished at a facility licensed under 10 CFR Part 70 to produce ore that can be processed at a conventional uranium mill licensed under 10 CFR Part 40.« less

Process and apparatus for solvent extraction of oil from oil-containing diatomite ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Karnofsky, G.B.

1979-09-11

A process is described for solvent extraction of oil-bearing diatomite ore. An apparatus is provided for use therewith, wherein the ore is extracted by countercurrent decantation with a hydrocarbon solvent. The solvent is recovered from the extract by multiple effect evaporation followed by stripping, and the spent diatomite is contacted with water to displace a major portion of the solvent therefrom. The solvent is recovered from the aqueous slurry of the spent diatomite by stripping with steam at superatmospheric pressure. 17 claims.

DISSOLUTION AND ANALYSIS OF YELLOWCAKE COMPONENTS FOR FINGERPRINTING UOC SOURCES

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hexel, Cole R; Bostick, Debra A; Kennedy, Angel K

2012-01-01

There are a number of chemical and physical parameters that might be used to help elucidate the ore body from which uranium ore concentrate (UOC) was derived. It is the variation in the concentration and isotopic composition of these components that can provide information as to the identity of the ore body from which the UOC was mined and the type of subsequent processing that has been undertaken. Oak Ridge National Laboratory (ORNL) in collaboration with Lawrence Livermore and Los Alamos National Laboratories is surveying ore characteristics of yellowcake samples from known geologic origin. The data sets are being incorporatedmore » into a national database to help in sourcing interdicted material, as well as aid in safeguards and nonproliferation activities. Geologic age and attributes from chemical processing are site-specific. Isotopic abundances of lead, neodymium, and strontium provide insight into the provenance of geologic location of ore material. Variations in lead isotopes are due to the radioactive decay of uranium in the ore. Likewise, neodymium isotopic abundances are skewed due to the radiogenic decay of samarium. Rubidium decay similarly alters the isotopic signature of strontium isotopic composition in ores. This paper will discuss the chemical processing of yellowcake performed at ORNL. Variations in lead, neodymium, and strontium isotopic abundances are being analyzed in UOC from two geologic sources. Chemical separation and instrumental protocols will be summarized. The data will be correlated with chemical signatures (such as elemental composition, uranium, carbon, and nitrogen isotopic content) to demonstrate the utility of principal component and cluster analyses to aid in the determination of UOC provenance.« less

Radon exhalation study of manganese clay residue and usability in brick production.

PubMed

Kovács, Tibor; Shahrokhi, Amin; Sas, Zoltán; Vigh, Tamás; Somlai, János

2017-03-01

The reuse of by-products and residue streams is an important topic due to environmental and financial aspects. Manganese clay is a residue of manganese ore processing and is generated in huge amounts. This residue may contain some radionuclides with elevated concentrations. In this study, the radon emanation features and the massic exhalation rate of the heat-treated manganese clay were determined with regard to brick production. From the manganese mud depository, 20 samples were collected and after homogenization radon exhalation characteristics were determined as a function of firing temperatures from 100 to 750 °C. The major naturally occurring radionuclides 40 K, 226 Ra and 232 Th concentrations were 607 ± 34, 52 ± 6 and 40 ± 5 Bq kg -1 , respectively, comparable with normal clay samples. Similar to our previous studies a strong correlation was found between the internal structure and the radon emanation. The radon emanation coefficient decreased by ∼96% from 0.23 at 100 °C to 0.01 at 750 °C. The massic radon exhalation rate of samples fired at 750 °C reduced by 3% compared to samples fired at 100 °C. In light of the results, reusing of manganese clay as a brick additive is possible without any constraints. Copyright © 2016 Elsevier Ltd. All rights reserved.

The impact of bacteria of circulating water on apatite-nepheline ore flotation.

PubMed

Evdokimova, G A; Gershenkop, A Sh; Fokina, N V

2012-01-01

A new phenomenon has been identified and studied-the impact of bacteria on the benefication process of non-sulphide ores using circulating water supply-a case study of apatite-nepheline ore. It is shown that bacteria deteriorate the floatability of apatite due to their interaction with active centres of calcium-containing minerals and intense flocculation, resulting in a decrease of the flotation process selectivity thus deteriorating the quality of concentrate. Based on the comparative analysis of primary sequences of 16S rRNA genes, there have been identified dominating bacteria species, recovered from the circulating water used at apatite-nepheline concentrating mills, and their phylogenetic position has been determined. All the bacteria were related to γ-Proteobacteria, including the Acinetobacter species, Pseudomonas alcaliphila, Ps. plecoglossicida, Stenotrophomonas rhizophila. A method of non-sulphide ores flotation has been developed with consideration of the bacterial factor. It consists in use of small concentrations of sodium hypochlorite, which inhibits the development of bacteria in the flotation of apatite-nepheline ores.

Recovery of magnetite from low grade banded magnetite quartzite (BMQ) ore

NASA Astrophysics Data System (ADS)

Tripathy, Alok; Bagchi, Subhankar; Rao, Danda Srinivas; Nayak, Bijaya Ketana; Rout, Prashanta Kumar; Biswal, Surendra Kumar

2018-04-01

There has been a steady increase of iron ore demand in the last few decades. This growing demand could be countered by use of low grade iron ore after beneficiation. Banded iron formations (BIF) are one of the resources of such low grade iron ores. Banded magnetite quartzite (BMQ) is one such BIF and a source of iron phase mineral in the form of magnetite. In the present study a low grade BMQ ore containing around 25.47% Fe was beneficiated for recovery of magnetite. XRD study shows that quartz, magnetite, hematite, and goethite are the major minerals phases present in the low grade BMQ sample. Unit operations such as crushing, scrubbing, grinding, and magnetic separations were used for recovering magnetite. Based on the large scale beneficiation studies the process flowsheet has been developed for enrichment of magnetite. It was found that with the help of developed process flowsheet it is possible to enrich Fe value up to 65.14% in the concentrate with a yield of 24.59%.

PROCESS OF RECOVERING URANIUM FROM ITS ORES

DOEpatents

Galvanek, P. Jr.

1959-02-24

A process is presented for recovering uranium from its ores. The crushed ore is mixed with 5 to 10% of sulfuric acid and added water to about 5 to 30% of the weight of the ore. This pugged material is cured for 2 to 3 hours at 100 to 110 deg C and then cooled. The cooled mass is nitrate-conditioned by mixing with a solution equivalent to 35 pounds of ammunium nitrate and 300 pounds of water per ton of ore. The resulting pulp containing 70% or more solids is treated by upflow percolation with a 5% solution of tributyl phosphate in kerosene at a rate equivalent to a residence time of about one hour to extract the solubilized uranium. The uranium is recovered from the pregnant organic liquid by counter-current washing with water. The organic extractant may be recycled. The uranium is removed from the water solution by treating with ammonia to precipitate ammonium diuranate. The filtrate from the last step may be recycled for the nitrate-conditioning treatment.

Hydrogen Plasma Processing of Iron Ore

NASA Astrophysics Data System (ADS)

Sabat, Kali Charan; Murphy, Anthony B.

2017-06-01

Iron is currently produced by carbothermic reduction of oxide ores. This is a multiple-stage process that requires large-scale equipment and high capital investment, and produces large amounts of CO2. An alternative to carbothermic reduction is reduction using a hydrogen plasma, which comprises vibrationally excited molecular, atomic, and ionic states of hydrogen, all of which can reduce iron oxides, even at low temperatures. Besides the thermodynamic and kinetic advantages of a hydrogen plasma, the byproduct of the reaction is water, which does not pose any environmental problems. A review of the theory and practice of iron ore reduction using a hydrogen plasma is presented. The thermodynamic and kinetic aspects are considered, with molecular, atomic and ionic hydrogen considered separately. The importance of vibrationally excited hydrogen molecules in overcoming the activation energy barriers, and in transferring energy to the iron oxide, is emphasized. Both thermal and nonthermal plasmas are considered. The thermophysical properties of hydrogen and argon-hydrogen plasmas are discussed, and their influence on the constriction and flow in the of arc plasmas is considered. The published R&D on hydrogen plasma reduction of iron oxide is reviewed, with both the reduction of molten iron ore and in-flight reduction of iron ore particles being considered. Finally, the technical and economic feasibility of the process are discussed. It is shown that hydrogen plasma processing requires less energy than carbothermic reduction, mainly because pelletization, sintering, and cokemaking are not required. Moreover, the formation of the greenhouse gas CO2 as a byproduct is avoided. In-flight reduction has the potential for a throughput at least equivalent to the blast furnace process. It is concluded that hydrogen plasma reduction of iron ore is a potentially attractive alternative to standard methods.

Dzhida Ore District: Geology, Structural and Metallogenic Regionalization, Genetic Types of Ore Deposits, Geodynamic Conditions of Their Formation, Forecast, and Outlook for Development

NASA Astrophysics Data System (ADS)

Gordienko, I. V.; Gorokhovsky, D. V.; Smirnova, O. K.; Lantseva, V. S.; Badmatsyrenova, R. A.; Orsoev, D. A.

2018-01-01

Based on complex structural, rheological, and metallogenic studies, taking into account the results of earlier subject-specific, prospecting, mapping, and exploration works, it has been established that the geological structure of the district was caused by the ensimatic evolution of the Vendian-Early Paleozoic Dzhida island-arc system, in which oceanic and island-arc complexes served as a melanocratic basement for Late Paleozoic-Mesozoic active within-plate (riftogenic) processes, which gave rise to the formation of ore deposits and occurrences of strategic mineral commodities (Mo, W, Au, Pt, Ag, and rare elements, including REE). Mantle plumes and flows of deep-seated transmagmatic solutions (ore-forming fluids) played a critical role in these processes, the significance of which increases in upper crustal swarms of dikes and fault systems. The forecasts and development prospects of the Dzhida ore district envisage the expansion of geological prospecting and exploration, scientific research, and technological testing of ore for insight into strategic mineral commodities, as well as reanimation of mining within the areas of the Dzhida's large territorial and industrial complex (TIC) in eastern Siberia.

Microbial reduction of iron ore

DOEpatents

Hoffmann, M.R.; Arnold, R.G.; Stephanopoulos, G.

1989-11-14

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry. 11 figs.

Microbial reduction of iron ore

DOEpatents

Hoffmann, Michael R.; Arnold, Robert G.; Stephanopoulos, Gregory

1989-01-01

A process is provided for reducing iron ore by treatment with microorganisms which comprises forming an aqueous mixture of iron ore, microorganisms operable for reducing the ferric iron of the iron ore to ferrous iron, and a substrate operable as an energy source for the microbial reduction; and maintaining the aqueous mixture for a period of time and under conditions operable to effect the reduction of the ore. Preferably the microorganism is Pseudomonas sp. 200 and the reduction conducted anaerobically with a domestic wastewater as the substrate. An aqueous solution containing soluble ferrous iron can be separated from the reacted mixture, treated with a base to precipitate ferrous hydroxide which can then be recovered as a concentrated slurry.

Factors affecting the partitioning of Cu, Zn and Pb in boulder coatings and stream sediments in the vicinity of a polymetallic sulfide deposit

USGS Publications Warehouse

Filipek, L.H.; Chao, T.T.; Carpenter, R.H.

1981-01-01

A sequential extraction scheme is utilized to determine the geochemical partitioning of Cu, Zn and Pb among hydrous Mn- and Fe-oxides, organics and residual crystalline silicates and oxides in the minus-80-mesh ( Fe-oxides > Mn-oxides; Zn, Mn-oxides {reversed tilde equals} organics > Fe-oxides; Pb, Fe-oxides > organics > Mn-oxides. In the sediments, organics are the most efficient scavengers of all three ore metals. These results emphasize the importance of organics as sinks for the ore metals, even in environments with high concentrations of Mn- and Fe-oxides. Of the ore metals, Zn appears to be the most mobile, and is partitioned most strongly into the coatings. However, anomaly contrast for hydromorphic Zn, normalized to the MnFe-oxide or organic content, is similar in sediments and coatings. Cu shows the highest anomaly on the boulder coatings, probably due to precipitation of a secondary Cu mineral. In contrast, detrital Pb in the pan concentrates shows a better anomaly than any hydromorphic Pb component. ?? 1981.

Precipitation of lead-zinc ores in the Mississippi Valley-type deposit at Treves, Cevennes region of southern France

USGS Publications Warehouse

Leach, D.; Macquar, J.-C.; Lagneau, V.; Leventhal, J.; Emsbo, P.; Premo, W.

2006-01-01

The Trèves zinc–lead deposit is one of several Mississippi Valley-type (MVT) deposits in the Cévennes region of southern France. Fluid inclusion studies show that the ore was deposited at temperatures between approximately 80 and 150°C from a brine that derived its salinity mainly from the evaporation of seawater past halite saturation. Lead isotope studies suggest that the metals were extracted from local basement rocks. Sulfur isotope data and studies of organic matter indicate that the reduced sulfur in the ores was derived from the reduction of Mesozoic marine sulfate by thermochemical sulfate reduction or bacterially mediated processes at a different time or place from ore deposition. The large range of δ34S values determined for the minerals in the deposit (12.2–19.2‰ for barite, 3.8–13.8‰ for sphalerite and galena, and 8.7 to −21.2‰ for pyrite), are best explained by the mixing of fluids containing different sources of sulfur. Geochemical reaction path calculations, based on quantitative fluid inclusion data and constrained by field observations, were used to evaluate possible precipitation mechanisms. The most important precipitation mechanism was probably the mixing of fluids containing different metal and reduced sulfur contents. Cooling, dilution, and changes in pH of the ore fluid probably played a minor role in the precipitation of ores. The optimum results that produced the most metal sulfide deposition with the least amount of fluid was the mixing of a fluid containing low amounts of reduced sulfur with a sulfur-rich, metal poor fluid. In this scenario, large amounts of sphalerite and galena are precipitated, together with smaller quantities of pyrite precipitated and dolomite dissolved. The relative amounts of metal precipitated and dolomite dissolved in this scenario agree with field observations that show only minor dolomite dissolution during ore deposition. The modeling results demonstrate the important control of the reduced sulfur concentration on the Zn and Pb transport capacity of the ore fluid and the volumes of fluid required to form the deposit. The studies of the Trèves ores provide insights into the ore-forming processes of a typical MVT deposit in the Cévennes region. However, the extent to which these processes can be extrapolated to other MVT deposits in the Cévennes region is problematic. Nevertheless, the evidence for the extensive migration of fluids in the basement and sedimentary cover rocks in the Cévennes region suggests that the ore forming processes for the Trèves deposit must be considered equally viable possibilities for the numerous fault-controlled and mineralogically similar MVT deposits in the Cévennes region.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kirk, D.W.

The generation of industrial solid wastes containing leachable species of environmental concern is a problem for developing and developed nations alike. These materials arise from direct processing of mineral ores, from production of metals and minerals, from manufacturing operations, and from air and water pollution treatment processes. The general characteristics that make these wastes intractable is that their content of hazardous species is not easily liberated from the waste yet is not bound so tightly that they are safe for landfill disposal or industrial use. The approach taken in this work is a thermal treatment that separates the inorganic contaminantsmore » from the wastes. The objective is to provide recovery and reuse of both the residual solids and liberated contaminants. The results from operating this technique using two very different types of waste are described. The reasons that the process will work for a wide variety of wastes are explored. By using the knowledge of the thermodynamic stability of the phases found from the characterization analyses, a thermal regime was found that allowed separation of the contaminants without capturing the matrix materials. Bench scale studies were carried out using a tube furnace. Samples of the wastes were heated in crucible boats from 750 to 1150{degrees}C in the presence of various chlorinating agents. The offgas contained 90{sup +}% of the targeted contaminants despite their complex matrix form. The residue was free of contamination. As a result of the efficient concentrating mechanism of the process, the contaminants in the offgas solids are attractive for reuse in metallurgical industries. As an additional benefit, the organic contaminants of the residues were eliminated. Dioxin traces in the solids before treatment were absent after treatment. 15 refs., 4 figs., 4 tabs.« less

Ferric minerals and organic matter change arsenic speciation in copper mine tailings.

PubMed

Wang, Peng; Liu, Yunjia; Menzies, Neal W; Wehr, J Bernhard; de Jonge, Martin D; Howard, Daryl L; Kopittke, Peter M; Huang, Longbin

2016-11-01

Arsenic (As) is commonly associated with Cu ore minerals, with the resultant risk that As can be released offsite from mine tailings. We used synchrotron-based fluorescence X-ray absorption near-edge spectroscopy (XANES) imaging to provide in situ, laterally-resolved speciation of As within tailings which differed in magnetite content (5-12%) and organic matter content (0-5%). Although the total As content was lower in tailings with low magnetite (LM), the soluble (pore water) As was actually 7-times higher in LM tailings than in high magnetite (HM) tailings. Additionally, amendment with 5% sugarcane mulch residues (SMR) (for revegetation) further increased soluble As due to the dissolution and oxidation of arsenopyrite or orpiment. Indeed, in HM tailings, arsenopyrite and orpiment initially accounted for 88% of the total As, which decreased to 48% upon the addition of SMR - this being associated with an increase in As V -ferrihydrite from 12% to 52%. In LM tailings, the pattern of As distribution and speciation was similar, with As as As V -ferrihydrite increasing from 57% to 75% upon the addition of SMR. These findings indicate that changes in ore processing technology, such as the recovery of magnetite could have significant environmental consequences regarding the As mobilisation and transformation in mine tailings. Copyright © 2016 Elsevier Ltd. All rights reserved.

Mineralogical and geochemical characteristics of the Noamundi-Koira basin iron ore deposits (India)

NASA Astrophysics Data System (ADS)

Mirza, Azimuddin; Alvi, Shabbar Habib; Ilbeyli, Nurdane

2015-04-01

India is one of the richest sources of iron ore deposits in the world; and one of them is located in the Noamundi-Koira basin, Singhbhum-Orissa craton. The geological comparative studies of banded iron formation (BIF) and associated iron ores of Noamundi-Koira iron ore deposits, belonging to the iron ore group in eastern India, focus on the study of mineralogy and major elemental compositions along with the geological evaluation of different iron ores. The basement of the Singhbhum-Orissa craton is metasedimentary rocks which can be traced in a broadly elliptical pattern of granitoids, surrounded by metasediments and metavolcanics of Greenstone Belt association. The Singhbhum granitoid is intrusive into these old rocks and to younger, mid Archaean metasediments, including iron formations, schists and metaquartzites and siliciclastics of the Precambrian Iron Ore Group (Saha et al., 1994; Sharma, 1994). The iron ore of Noamundi-Koira can be divided into seven categories (Van Schalkwyk and Beukes 1986). They are massive, hard laminated, soft laminated, martite-goethite, powdery blue dust and lateritic ore. Although it is more or less accepted that the parent rock of iron ore is banded hematite jasper (BHJ), the presence of disseminated martite in BHJ suggests that the magnetite of protore was converted to martite. In the study area, possible genesis of high-grade hematite ore could have occurred in two steps. In the first stage, shallow, meteoric fluids affect primary, unaltered BIF by simultaneously oxidizing magnetite to martite and replacing quartz with hydrous iron oxides. In the second stage of supergene processes, deep burial upgrades the hydrous iron oxides to microplaty hematite. Removal of silica from BIF and successive precipitation of iron resulted in the formation of martite- goethite ore. Soft laminated ores were formed where precipitation of iron was partial or absent. The leached out space remains with time and the interstitial space is generally filled with kaolinite and gibbsite, which make it low grade. Massive iron ores are devoid of any lamination and usually associated with BHJ and lower shale. The thickness of the massive ore layer varies with the location. The massive iron ore grades in to well-developed bedded BHJ in depth. Blue dust occurs in association with BHJ as pockets and layers. Although blue dust and friable ore are both powdery ores, and subjected to variable degree of deformation, leading to the formation of folding, faulting and joints of complex nature produce favourable channels. Percolating water play an important role in the formation of blue dust and the subterranean solution offers the necessary acidic environment for leaching of quartz from the BHJ. The dissolution of silica and other alkalis are responsible for the formation of blue dust. The friable and powdery ore on the other hand are formed by soft laminated ore. As it is formed from the soft laminated ore, its alumina content remains high similar to soft laminated ore compaired to blue dust. Mineralogy study suggests that magnetite was the principal iron oxide mineral, now a relict phase whose depositional history is preserved in BHJ, where it remains in the form of martite. The platy hematite is mainly the product of martite. The different types of iron ores are intricately related with the BHJ. Hard laminated ores, martite-goethite ore and soft laminated ore are resultant of desilicification process through the action of hydrothermal fluids. Geochemistry of banded iron-formations of the Noamundi-Koira iron ore deposits shows that they are detritus-free chemical precipitates. The mineralogical and geochemical data suggest that the hard laminated, massive, soft laminated ores and blue dust had a genetic lineage from BIF's aided with certain input from hydrothermal activity. The comparative study of major elemental composition of the basin samples and while plotting a binary diagram, it shows a relation between major oxides against iron oxides, in which iron oxides is taken as a reference oxide (Mirza, 2011). On the other hand, by plotting a binary diagram between chemical index of alteration (CIA) and other oxides while taking the samples of lower, middle and upper shales. It reflects an immobility and mobility of ions during partial and complete weathering processes (Mirza, 2011). Geochemical data indicate that BIF are in general detritus free chemical precipitates. Fe2O3 content of BHJ are varies in between 36.6% to 65.04%. In hard laminated ore, Fe2O3 content varies from 93.8% to 96.38%, Soft laminated ore varies from 83.64% to 89.5% and laterite ore varies from 53.5% to 79.11%. Fe2O3 content in Martite- Goethite ore varies from 86.38% to 89.42% and blue dust having 90.74% to 95.86% and all other oxides like SiO2, Al2O3, CaO, MgO, K2O, Na2O are decreases. Major part of the iron could have been added to the bottom sea water by hydrothermal solutions derived from hydrothermally active anoxic marine environments. The presence of intacalated tuffaceous shales pointing towards the genesis of iron, which could have leached from sea floor by volcanogenic process. Iron and silica of BIF were provided by the hydrothermal solutions emplaced at the vent sites situated at the Archean-Mid Oceanic Ridges. References: Mirza A (2011). Major element geochemistry of iron ore deposits in Noamundi-Koira basin of Singhbhum-Orissa craton (India). MSc thesis, Aligarh Muslim University, India. Saha AK (1994). Crustal evolution of Singhbhum, North Orissa, Eastern India; Geol. Soc. India Memoir 27 341. Sharma M, Basu AR and Ray SL (1994). Sm-Nd isotopic and geochemical study of the Archaean tonalite-amphibolite association from the eastern Indian craton. Contrib. Mineral Petrol. 117:45-55. Van Schalkwyk J and Beukes N J (1986). The Sishen iron ore deposit, Griqualand West; In: Mineral deposits of Southern Africa (eds) Annhaeusser C R and Maske S S, Geological Society of South Africa, Johannesburg, 931-956.

Possible lunar ores

NASA Technical Reports Server (NTRS)

Gillett, Stephen L.

1991-01-01

Despite the conventional wisdom that there are no lunar ores, geochemical considerations suggest that local concentrations of useful rare elements exist on the Moon in spite of its extreme dryness. The Moon underwent protracted igneous activity in its history, and certain magmatic processes can concentrate incompatible elements even if anhydrous. Such processes include: (1) separation of a magma into immiscible liquid phases (depending on composition, these could be silicate-silicate, silicate-oxide, silicate-sulfide, or silicate-salt); (2) cumulate deposits in layered igneous intrusions; and (3) concentrations of rare, refractory, lithophile elements (e.g., Be, Li, Zr) in highly differentiated, silica-rich magmas, as in the lunar granites. Terrestrial mining experience indicates that the single most important characteristic of a potential ore is its concentration of the desire element. The utility of a planet as a resource base is that the welter of interacting processes over geologic time can concentrate rare element automatically. This advantage is squandered if adequate exploration for ores is not first carried out.

Purification of trona ores by conditioning with an oil-in-water emulsion

DOEpatents

Miller, J. D.; Wang, Xuming; Li, Minhua

2009-04-14

The present invention is a trona concentrate and a process for floating gangue material from trona ore that comprises forming an emulsion, conditioning the trona ore at a high solids content in a saturated trona suspension, and then floating and removing the gangue material. The process for separating trona from gangue materials in trona ore can include emulsifying an oil in an aqueous solution to form an oil-in-water emulsion. A saturated trona suspension having a high solids content can also be formed having trona of a desired particle size. The undissolved trona in the saturated suspension can be conditioned by mixing the saturated suspension and the oil-in-water emulsion to form a conditioning solid suspension of trona and gangue material. A gas can be injected through the conditioning solid suspension to float the gangue material. Thus, the floated gangue material can be readily separated from the trona to form a purified trona concentrate without requirements of additional heat or other expensive processing steps.

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2013 CFR

2013-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2012 CFR

2012-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2014 CFR

2014-07-01

... GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine... control: The amount of new water allowed to enter the plant site for use in ore processing shall be...

The Resin-in-pulp Process and Its Application to Ores from Brosses "BRS 10"; LE PROCEDE "RESIN IN PULP" ET SON APPLICATION AUX MINERAIS DES BROSSES "BRS 10"

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kremer, M.

1959-03-01

The resin-in-pulp process is a technical variant of the recovery process of uranium in dilute solution by means of ion exchange resins. An anion resin, XE 123, of a welldefined grain size is placed in direct contact with the pulp produced by sulfuric acid attack on ore with a low uranium content. This process is of particular value in the treatment of pulps that cannot be filtered or decanted, such as those obtained with ore from Brosses. The preparation of the pulp, the elution of the uranium, and its fixation, as well as the various factors encountered in these operations,more » are discussed. (auth)« less

Investigation of sulphur isotope variation due to different processes applied during uranium ore concentrate production.

PubMed

Krajkó, Judit; Varga, Zsolt; Wallenius, Maria; Mayer, Klaus; Konings, Rudy

The applicability and limitations of sulphur isotope ratio as a nuclear forensic signature have been studied. The typically applied leaching methods in uranium mining processes were simulated for five uranium ore samples and the n ( 34 S)/ n ( 32 S) ratios were measured. The sulphur isotope ratio variation during uranium ore concentrate (UOC) production was also followed using two real-life sample sets obtained from industrial UOC production facilities. Once the major source of sulphur is revealed, its appropriate application for origin assessment can be established. Our results confirm the previous assumption that process reagents have a significant effect on the n ( 34 S)/ n ( 32 S) ratio, thus the sulphur isotope ratio is in most cases a process-related signature.

Processing of metal and oxygen from lunar deposits

NASA Technical Reports Server (NTRS)

Acton, Constance F.

1992-01-01

On the moon, some whole rocks may be ores for abundant elements, such as oxygen, but beneficiation will be important if metallic elements are sought from raw lunar dirt. In the extraction process, a beneficiated metallic ore, such as an oxide, sulfide, carbonate, or silicate mineral, is converted to reduced metal. A variety of plausible processing technologies, which includes recovery of meteoritic iron, and processing of lunar ilmenite, are described in this report.

Lead-isotopic, sulphur-isotopic, and trace-element studies of galena from the Silesian-Cracow Zn-Pb ores, polymetallic veins from the Gory Swietokrzyskie MTS, and the Myszkow porphyry copper deposit, Poland

USGS Publications Warehouse

Church, S.E.; Vaughn, R.B.; Gent, C.A.; Hopkins, R.T.

1996-01-01

Lead-isotopic data on galena samples collected from a paragenetically constrained suite of samples from the Silesian-Cracow ore district show no regional or paragenetically controlled lead-isotopic trends within the analytical reproducibility of the measurements. Furthermore, the new lead-isotopic data agree with previously reported lead-isotopic results (R. E. Zartman et al., 1979). Sulfur-isotopic analyses of ores from the Silesian-Cracow district as well as from vein ore from the Gory Swietokrzyskie Mts. and the Myszkow porphyry copper deposit, when coupled with trace-element data from the galena samples, clearly discriminate different hydrothermal ore-forming events. Lead-isotopic data from the Permian and Miocene evaporite deposits in Poland indicate that neither of these evaporite deposits were a source of metals for the Silesian-Cracow district ores. Furthermore, lead-isotopic data from these evaporite deposits and the shale residues from the Miocene halite samples indicate that the crustal evolution of lead in the central and western European platform in southern Poland followed normal crustal lead-isotopic growth, and that the isotopic composition of crustal lead had progressed beyond the lead-isotopic composition of lead in the Silesian-Cracow ores by Permian time. Thus, Mesozoic and Tertiary sedimentary flysch rocks can be eliminated as viable source rocks for the metals in the Silesian-Cracow Mississippi Valley-type (MVT) deposits. The uniformity of the isotopic composition of lead in the Silesian-Cracow ores, when coupled with the geologic evidence that mineralization must post-date Late Jurassic faulting (E. Gorecka, 1991), constrains the geochemical nature of the source region. The source of the metals is probably a well-mixed, multi-cycle molasse sequence of sedimentary rocks that contains little if any Precambrian metamorphic or granitic clasts (S. E. Church, R. B. Vaughn, 1992). If ore deposition was post Late Jurassic (about 150 m. y.) or later as indicated by the geologic evidence, the source rocks probably contained elevated concentrations of Zn and Pb (75-100 ppm), and relatively low concentrations of U and Th (2 and 8 ppm or less, respectively). The Carboniferous coal-bearing molasse rocks of the Upper Silesian Coal Basin are a prime candidate for such a source region. The presence of ammonia and acetate in the fluid inclusions (Viets et al., 1996a) also indicate that the Carboniferous coal-bearing molasse sequence in the Upper Silesian Coal Basin may have been a suitable pathway for the MVT ore fluids. The lead-isotopic homogeneity, when coupled with the sulfur-isotopic heterogeneity of the ores suggests that mixing of a single metal-bearing fluid with waters from separate aquifers containing variable sulfur-isotopic compositions in karsts in the Muschelkalk Formation of Middle Triassic age may have been responsible for the precipitation of the ores of the Silesian-Cracow district.

Thermodynamic Analysis of the Selective Reduction of a Nickeliferous Limonitic Laterite Ore by Hydrogen

NASA Astrophysics Data System (ADS)

Elliott, R.; Pickles, C. A.

2017-09-01

Nickeliferous limonitic laterite ores are becoming increasingly attractive as a source of metallic nickel as the costs associated with recovering nickel from the sulphide ores increase. Unlike the sulphide ores, however, the laterite ores are not amenable to concentration by conventional mineral processing techniques such as froth flotation. One potential concentrating method would be the pyrometallurgical solid state reduction of the nickeliferous limonitic ores at relatively low temperatures, followed by beneficiation via magnetic separation. A number of reductants can be utilized in the reduction step, and in this research, a thermodynamic model has been developed to investigate the reduction of a nickeliferous limonitic laterite by hydrogen. The nickel recovery to the ferronickel phase was predicted to be greater than 95 % at temperatures of 673-873 K. Reductant additions above the stoichiometric requirement resulted in high recoveries over a wider temperature range, but the nickel grade of the ferronickel decreased.

Nonlinear metallogeny and the depths of the earth

NASA Astrophysics Data System (ADS)

Shcheglov, A. D.; Govorov, I. N.

This book is concerned with the basic relations regarding a new approach in the field of knowledge of metallogenesis, taking into account the complex character of the mutual dependence between ore deposits, the structure of the earth's crust, and depth relations. The principles of nonlinear metallogeny are examined, giving attention to the development of the metallogenic science during the past few years, the formation of the concept 'nonlinear metallogeny', the main aspects of nonlinear metallogeny, the origin of the ore deposits and the characteristics of ore formations in the mantle, the parallel manifestation of ore-forming processes in the crust, sedimentary-hydrothermal ore formations and their place in nonlinear metallogeny, and various types of rock and ore formations. The structure, composition, and metalliferous characteristics found at various depth zones of the tectonosphere are discussed along with the geochemical and metallogenic heterogeneity in the mantle. General questions of nonlinear metallogeny are also investigated.

Safeguards on uranium ore concentrate? the impact of modern mining and milling process

DOE Office of Scientific and Technical Information (OSTI.GOV)

Francis, Stephen

2013-07-01

Increased purity in uranium ore concentrate not only raises the question as to whether Safeguards should be applied to the entirety of uranium conversion facilities, but also as to whether some degree of coverage should be moved back to uranium ore concentrate production at uranium mining and milling facilities. This paper looks at uranium ore concentrate production across the globe and explores the extent to which increased purity is evident and the underlying reasons. Potential issues this increase in purity raises for IAEA's strategy on the Starting Point of Safeguards are also discussed.

The action of macrosounds on graphite ore and derived products

NASA Technical Reports Server (NTRS)

Bradeteanu, C.; Dragan, O.

1974-01-01

A suspension of graphite ore, floated graphite, and the gangue left over from flotation were subjected to the action of macrosounds under determinant conditions. The following was found: (1) The graphite ore undergoes an efficient settling action. (2) The floated graphite is strongly crushed down to the dimensions of colloidal graphite. (3) The gangue left over from flotation can be further processed to recuperate graphite from its nuclei.

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE PAGES

Balboni, Enrica; Jones, Nina; Spano, Tyler; ...

2016-08-31

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Chemical and Sr isotopic characterization of North America uranium ores: Nuclear forensic applications

DOE Office of Scientific and Technical Information (OSTI.GOV)

Balboni, Enrica; Jones, Nina; Spano, Tyler

This study reports major, minor, and trace element data and Sr isotope ratios for 11 uranium ore (uraninite, UO 2+x) samples and one processed uranium ore concentrate (UOC) from various U.S. deposits. The uraninite investigated represent ores formed via different modes of mineralization (e.g., high- and low-temperature) and within various geological contexts, which include magmatic pegmatites, metamorphic rocks, sandstone-hosted, and roll front deposits. In situ trace element data obtained by laser ablation-ICP-MS and bulk sample Sr isotopic ratios for uraninite samples investigated here indicate distinct signatures that are highly dependent on the mode of mineralization and host rock geology. Relativemore » to their high-temperature counterparts, low-temperature uranium ores record high U/Th ratios (>1000), low total rare earth element (REE) abundances (<1 wt%), high contents (>300 ppm) of first row transition metals (Sc, Ti, V, Cr, Mn, Co, Ni), and radiogenic 87Sr/ 86Sr ratios (>0.7200). Comparison of chondrite normalized REE patterns between uraninite and corresponding processed UOC from the same locality indicates identical patterns at different absolute concentrations. Lastly, this result ultimately confirms the importance of establishing geochemical signatures of raw, uranium ore materials for attribution purposes in the forensic analysis of intercepted nuclear materials.« less

Cyanide hazards to plants and animals from gold mining and related water issues

USGS Publications Warehouse

Eisler, R.; Wiemeyer, Stanley N.

2004-01-01

Highly toxic sodium cyanide (NaCN) is used by the international mining community to extract gold and other precious metals through milling of high-grade ores and heap leaching of low-grade ores (Korte et al. 2000). The process to concentrate gold using cyanide was developed in Scotland in 1887 and was used almost immediately in the Witwatersrand gold fields of the Republic of South Africa. Heap leaching with cyanide was proposed by the U.S. Bureau of Mines in 1969 as a means of extracting gold from low-grade ores. The gold industry adopted the technique in the 1970s, soon making heap leaching the dominant technology in gold extraction (Da Rosa and Lyon 1997). The heap leach and milling processes, which involve dewatering of gold-bearing ores, spraying of dilute cyanide solutions on extremely large heaps of ores containing low concentrations of gold, or the milling of ores with the use of cyanide and subsequent recovery of the gold-cyanide complex, have created a number of serious environmental problems affecting wildlife and water management. In this account, we review the history of cyanide use in gold mining with emphasis on heap leach gold mining, cyanide hazards to plants and animals, water management issues associated with gold mining, and proposed mitigation and research needs.

Hemimorphite Ores: A Review of Processing Technologies for Zinc Extraction

NASA Astrophysics Data System (ADS)

Chen, Ailiang; Li, Mengchun; Qian, Zhen; Ma, Yutian; Che, Jianyong; Ma, Yalin

2016-10-01

With the gradual depletion of zinc sulfide ores, exploration of zinc oxide ores is becoming more and more important. Hemimorphite is a major zinc oxide ore, attracting much attention in the field of zinc metallurgy although it is not the major zinc mineral. This paper presents a critical review of the treatment for extraction of zinc with emphasis on flotation, pyrometallurgical and hydrometallurgical methods based on the properties of hemimorphite. The three-dimensional framework structure of hemimorphite with complex linkage of its structural units lead to difficult desilicification before extracting zinc in the many metallurgical technologies. It is found that the flotation method is generally effective in enriching zinc minerals from hemimorphite ores into a high-grade concentrate for recovery of zinc. Pure zinc can be produced from hemimorphite or/and willemite with a reducing reagent, like methane or carbon. Leaching reagents, such as acid and alkali, can break the complex structure of hemimorphite to release zinc in the leached solution without generation of silica gel in the hydrometallurgical process. For optimal zinc extraction, combing flotation with pyrometallurgical or hydrometallurgical methods may be required.

TREATMENT OF HEXAVALENT CHROMIUM IN CHROMITE ORE PROCESSING SOLID WASTE USING A MIXED REDUCTANT SOLUTION OF FERROUS SULFATE AND SODIUM DITHIONITE

EPA Science Inventory

We developed a method for disseminating ferrous iron in the subsurface to enhance chemical reduction of hexavalent chromium (Cr(VI)) in a chromite ore processing solid waste derived from the production of ferrochrome alloy. The method utilizes ferrous sulfate (FeSO4) in combinati...

Microwave enhanced recovery of nickel-copper ore: communition and floatability aspects.

PubMed

Henda, R; Hermas, A; Gedye, R; Islam, M R

2005-01-01

A study describing the effect of microwave radiation, at a frequency of 2450 MHz, on the processes of communication and flotation of a complex sulphide nickel-copper ore is presented. Ore communication has been investigated under standard radiation-free conditions and after ore treatment in a radiated environment as a function of ore size, exposure time to radiation, and microwave power. The findings show that communication is tremendously improved by microwave radiation with values of the relative work index as low as 23% at a microwave power of 1.406 kW and after 10 s of exposure time. Communication is affected by exposure time and microwave power in a nontrivial manner. In terms of ore floatability, the experimental tests have been carried out on a sample of 75 microm in size under different exposure times. The results show that both ore concentrate recoveries and grades of nickel and copper are significantly enhanced after microwave treatment of the ore with relative increases in recovered concentrate, grade of nickel, and grade of copper of 26 wt%, 15 wt%, and 27%, respectively, at a microwave power of 1330 kW and after 30 s of exposure time.

Selective Removal of Iron from Low-Grade Ti Ore by Reacting with Calcium Chloride

NASA Astrophysics Data System (ADS)

Kang, Jungshin; Okabe, Toru H.

2017-02-01

Recently, titanium metal production by molten salt electrolysis using CaCl2 as molten salt and TiO2 or rutile (94 to 96 pct TiO2) as feedstock has been drawing attention. However, when a low-grade Ti ore (mainly FeTiO3) is used as feedstock, removal of iron (Fe) from the ore is indispensable. In this study, the influence of reaction temperature, reaction time, particle size of the ore, and source country for the ore on the removal of iron by selective chlorination using CaCl2 was assessed. Experimental results showed that the mass percent of iron in the ore decreased from 49.7 to 1.79 pct under certain conditions by selective removal of iron as FeCl2. As a result, high-grade CaTiO3 was produced when the ore particles smaller than 74 µm reacted with CaCl2 at 1240 K (967 °C) for 8 to 10 hours. Therefore, this study demonstrates that the removal of iron from the ore is feasible through the selective chlorination process using CaCl2 by optimizing the variables.

Molybdenum mineralization related to the Yangtze's lower crust and differentiation in the Dabie Orogen: Evidence from the geochemical features of the Yaochong porphyry Mo deposit

NASA Astrophysics Data System (ADS)

Liu, Qing-Quan; Li, Bin; Shao, Yong-Jun; Lu, An-Huai; Lai, Jian-Qing; Li, Yong-Feng; Luo, Zheng-Zhuan

2017-06-01

The Dabie Orogen is a world-class case for large amounts of Mo mineralization in that it contains at least 10 porphyry Mo deposits with Mo metal reserves over 3 Mt from the time period of 156-110 Ma. However, the principal mechanism for the Mo mineralization remains controversial due to the lack of a precise definition of its source and shallow ore-forming process, which is essential to understand these rare large Mo deposits. Detailed geochronology, geochemistry, and isotopic data for ore-related granites and minerals were analyzed in order to place constraints on the massive Mo mineralization in the Dabie Orogen in eastern China. The Yaochong molybdenum orebodies were hosted in the transition belt and alteration zone between the granitic stocks and the Dabie Complex and were characterized as numerous veinlets with potassic, phyllic and propylitic alterations. The buried Yaochong granitic intrusions and associated molybdenum mineralization yield Early Cretaceous ages of magmatic activities at ca. 138 Ma and extremely similar Re-Os isotope ages for the corresponding Mo metallogenic event at ca. 137 Ma. The Yaochong monzogranite and granite porphyry belong to the highly fractionated I-type granites, which are believed to be derived from the dominantly Yangtze's lower crust mixed with the Northern Dabie Complex due to their geochemical and isotope features. The elemental diversity and isotopic homogeneity suggest that the formation of the Yaochong monzogranite involved the fractionation of biotite, garnet and minor feldspar and accessory minerals combined with a weak crustal assimilation process. In contrast, the granite porphyry was possibly generated by the partial melting of the same mixed lower continental crust via the differentiation process involving the fractionation of feldspar, apatite, and/or titanite. Fractional crystallization processes can significantly elevate the molybdenum concentration in the residual melts. The biotite fractional crystallization results in removal of molybdenum from the vestigial magma since molybdenum is compatible with it, which may account for the barren monzogranite with a low-grade molybdenum mineralization. The ore-bearing granite porphyry has more source materials from the Yangtze's lower crust, which may have contributed most of the molybdenum for the porphyry-related molybdenum deposits in the Dabie metallogenic zone. This porphyry molybdenum aggregation may have been deposited in a post-collision or intracontinental extensional setting.

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.30 - Applicability; description of the uranium, radium and vanadium ores subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... vanadium ores are produced; and (b) mills using the acid leach, alkaline leach, or combined acid and alkaline leach process for the extraction of uranium, radium and vanadium. Only vanadium byproduct...

40 CFR 440.148 - Best Management Practices (BMP).

Code of Federal Regulations, 2011 CFR

2011-07-01

... GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Gold Placer Mine Subcategory § 440.148...: The amount of new water allowed to enter the plant site for use in ore processing shall be limited to...

Beneficiation of the gold bearing ore by gravity and flotation

NASA Astrophysics Data System (ADS)

Gül, Alim; Kangal, Olgaç; Sirkeci, Ayhan A.; Önal, Güven

2012-02-01

Gold concentration usually consists of gravity separation, flotation, cyanidation, or the combination of these processes. The choice among these processes depends on the mineralogical characterization and gold content of the ore. Recently, the recovery of gold using gravity methods has gained attention because of low cost and environmentally friendly operations. In this study, gold pre-concentrates were produced by the stepwise gravity separation and flotation techniques. The Knelson concentrator and conventional flotation were employed for the recovery of gold. Gold bearing ore samples were taken from Gümüşhane Region, northern east part of Turkey. As a result of stepwise Knelson concentration experiments, a gold concentrate assaying around 620 g/t is produced with 41.4wt% recovery. On the other hand, a gold concentrate about 82 g/t is obtained with 89.9wt% recovery from a gold ore assaying 6 g/t Au by direct flotation.

Biomining-biotechnologies for extracting and recovering metals from ores and waste materials.

PubMed

Johnson, D Barrie

2014-12-01

The abilities of acidophilic chemolithotrophic bacteria and archaea to accelerate the oxidative dissolution of sulfide minerals have been harnessed in the development and application of a biotechnology for extracting metals from sulfidic ores and concentrates. Biomining is currently used primarily to leach copper sulfides and as an oxidative pretreatment for refractory gold ores, though it is also used to recover other base metals, such as cobalt, nickel and zinc. Recent developments have included using acidophiles to process electronic wastes, to extract metals from oxidized ores, and to selectively recover metals from process waters and waste streams. This review describes the microorganisms and mechanisms involved in commercial biomining operations, how the technology has developed over the past 50 years, and discusses the challenges and opportunities for mineral biotechnologies in the 21st century. Copyright © 2014 Elsevier Ltd. All rights reserved.

Thermodynamics of ultra-sonic cavitation bubbles in flotation ore processes

NASA Astrophysics Data System (ADS)

Royer, J. J.; Monnin, N.; Pailot-Bonnetat, N.; Filippov, L. O.; Filippova, I. V.; Lyubimova, T.

2017-07-01

Ultra-sonic enhanced flotation ore process is a more efficient technique for ore recovery than classical flotation method. A classical simplified analytical Navier-Stokes model is used to predict the effect of the ultrasonic waves on the cavitations bubble behaviour. Then, a thermodynamics approach estimates the temperature and pressure inside a bubble, and investigates the energy exchanges between flotation liquid and gas bubbles. Several gas models (including ideal gas, Soave-Redlich-Kwong, and Peng-Robinson) assuming polytropic transformations (from isothermal to adiabatic) are used to predict the evolution of the internal pressure and temperature inside the bubble during the ultrasonic treatment, together with the energy and heat exchanges between the gas and the surrounding fluid. Numerical simulation illustrates the suggest theory. If the theory is verified experimentally, it predicts an increase of the temperature and pressure inside the bubbles. Preliminary ultrasonic flotation results performed on a potash ore seem to confirm the theory.

Resource potential for commodities in addition to Uranium in sandstone-hosted deposits: Chapter 13

USGS Publications Warehouse

Breit, George N.

2016-01-01

Sandstone-hosted deposits mined primarily for their uranium content also have been a source of vanadium and modest amounts of copper. Processing of these ores has also recovered small amounts of molybdenum, rhenium, rare earth elements, scandium, and selenium. These deposits share a generally common origin, but variations in the source of metals, composition of ore-forming solutions, and geologic history result in complex variability in deposit composition. This heterogeneity is evident regionally within the same host rock, as well as within districts. Future recovery of elements associated with uranium in these deposits will be strongly dependent on mining and ore-processing methods.

Individual Differences in Holistic Processing Predict the Own-Race Advantage in Recognition Memory

PubMed Central

DeGutis, Joseph; Mercado, Rogelio J.; Wilmer, Jeremy; Rosenblatt, Andrew

2013-01-01

Individuals are consistently better at recognizing own-race faces compared to other-race faces (other-race effect, ORE). One popular hypothesis is that this recognition memory ORE is caused by differential own- and other-race holistic processing, the simultaneous integration of part and configural face information into a coherent whole. Holistic processing may create a more rich, detailed memory representation of own-race faces compared to other-race faces. Despite several studies showing that own-race faces are processed more holistically than other-race faces, studies have yet to link the holistic processing ORE and the recognition memory ORE. In the current study, we sought to use a more valid method of analyzing individual differences in holistic processing by using regression to statistically remove the influence of the control condition (part trials in the part-whole task) from the condition of interest (whole trials in the part-whole task). We also employed regression to separately examine the two components of the ORE: own-race advantage (regressing other-race from own-race performance) and other-race decrement (regressing own-race from other-race performance). First, we demonstrated that own-race faces were processed more holistically than other-race faces, particularly the eye region. Notably, using regression, we showed a significant association between the own-race advantage in recognition memory and the own-race advantage in holistic processing and that these associations were weaker when examining the other-race decrement. We also demonstrated that performance on own- and other-race faces across all of our tasks was highly correlated, suggesting that the differences we found between own- and other-race faces are quantitative rather than qualitative. Together, this suggests that own- and other-race faces recruit largely similar mechanisms, that own-race faces more thoroughly engage holistic processing, and that this greater engagement of holistic processing is significantly associated with the own-race advantage in recognition memory. PMID:23593119

Individual differences in holistic processing predict the own-race advantage in recognition memory.

PubMed

Degutis, Joseph; Mercado, Rogelio J; Wilmer, Jeremy; Rosenblatt, Andrew

2013-01-01

Individuals are consistently better at recognizing own-race faces compared to other-race faces (other-race effect, ORE). One popular hypothesis is that this recognition memory ORE is caused by differential own- and other-race holistic processing, the simultaneous integration of part and configural face information into a coherent whole. Holistic processing may create a more rich, detailed memory representation of own-race faces compared to other-race faces. Despite several studies showing that own-race faces are processed more holistically than other-race faces, studies have yet to link the holistic processing ORE and the recognition memory ORE. In the current study, we sought to use a more valid method of analyzing individual differences in holistic processing by using regression to statistically remove the influence of the control condition (part trials in the part-whole task) from the condition of interest (whole trials in the part-whole task). We also employed regression to separately examine the two components of the ORE: own-race advantage (regressing other-race from own-race performance) and other-race decrement (regressing own-race from other-race performance). First, we demonstrated that own-race faces were processed more holistically than other-race faces, particularly the eye region. Notably, using regression, we showed a significant association between the own-race advantage in recognition memory and the own-race advantage in holistic processing and that these associations were weaker when examining the other-race decrement. We also demonstrated that performance on own- and other-race faces across all of our tasks was highly correlated, suggesting that the differences we found between own- and other-race faces are quantitative rather than qualitative. Together, this suggests that own- and other-race faces recruit largely similar mechanisms, that own-race faces more thoroughly engage holistic processing, and that this greater engagement of holistic processing is significantly associated with the own-race advantage in recognition memory.

Application of indigenous sulfur-oxidizing bacteria from municipal wastewater to selectively bioleach phosphorus from high-phosphorus iron ore: effect of particle size.

PubMed

Shen, Shaobo; Rao, Ruirui; Wang, Jincao

2013-01-01

The effects of ore particle size on selectively bioleaching phosphorus (P) from high-phosphorus iron ore were studied. The average contents of P and Fe in the iron ore were 1.06 and 47.90% (w/w), respectively. The particle sizes of the ores used ranged from 58 to 3350 microm. It was found that the indigenous sulfur-oxidizing bacteria from municipal wastewater could grow well in the slurries of solid high-phosphorus iron ore and municipal wastewater. The minimum bioleaching pH reached for the current work was 0.33. The P content in bioleached iron ore reduced slightly with decreasing particle size, while the removal percentage of Fe decreased appreciably with decreasing particle size. The optimal particle size fraction was 58-75 microm, because the P content in bioleached iron ore reached a minimum of 0.16% (w/w), the removal percentage of P attained a maximum of 86.7%, while the removal percentage of Fe dropped to a minimum of 1.3% and the Fe content in bioleached iron ore was a maximum of 56.4% (w/w) in this case. The iron ores thus obtained were suitable to be used in the iron-making process. The removal percentage of ore solid decreased with decreasing particle size at particle size range of 106-3350 microm. The possible reasons resulting in above phenomena were explored in the current work. It was inferred that the particle sizes of the iron ore used in this work have no significant effect on the viability of the sulfur-oxidizing bacteria.

Sedimentary exhalative nickel-molybdenum ores in south China

USGS Publications Warehouse

Lott, D.A.; Coveney, R.M.; Murowchick, J.B.; Grauch, R.I.

1999-01-01

Unique bedded Ni-Mo ores hosted by black shales were discovered in localized paleobasins along the Yangzte platform of southern China in 1971. Textural evidence and radiometric dates imply ore formation during sedimentation of black shales that grade into readily combustible beds, termed stone coals, which contain 10 to 15 percent organic carbon. Studies of 427 fluid inclusions indicate extreme variation in hydrothermal brine salinities that were contained by Proterozoic dolostones underlying the ore zone in Hunan and Guizhou. Variations of fluid inclusion salinities, which range from 0.1 to 21.6 wt percent NaCl equiv, are attributed to differences in the compositions of brines in strata underlying the ore bed, complicated by the presence of seawater and dilute fluids that represent condensates of vapors generated by boiling of mineralizing fluids or Cambrian meteoric water. The complex processes of ore deposition led to scattered homogenization temperatures ranging from 100??to 187??C within the Hunan ore zone and from 65??to 183??C within the Guizhou ore zone. While living organisms probably did not directly accumulate metals in situ in sufficient amounts to explain the unusually high grades of the deposits, sulfur isotope ratios indicate that bacteria, now preserved as abundant microfossils, provided sufficient sulfide for the ores by reduction of seawater sulfate. Such microbiota may have depended on vent fluids and transported organic matter for key nutrients and are consistent with a sedex origin for the ores. Vent fluids interacted with organic remains, including rounded fragments of microbial mats that were likely transported to the site of ore deposition by the action of waves and bottom currents prior to replacement by ore minerals.

A MIXED CHEMICAL REDUCTANT FOR TREATING HEXAVALENT CHROMIUM IN A CHROMITE ORE PROCESSING SOLID WASTE

EPA Science Inventory

We evaluated a method for delivering ferrous iron into the subsurface to enhance chemical reduction of Cr(VI) in a chromite ore processing solid waste (COPSW). The COPSW is characterized by high pH (8.5 -11.5), high Cr(VI) concentrations in the solid phase (up to 550 mg kg-1) and...

Biotechnology for the extractive metals industries

NASA Astrophysics Data System (ADS)

Brierley, James A.

1990-01-01

Biotechnology is an alternative process for the extraction of metals, the beneficiation of ores, and the recovery of metals from aqueous systems. Currently, microbial-based processes are used for leaching copper and uranium, enhancing the recovery of gold from refractory ores, and treating industrial wastewater to recover metal values. Future developments, emanating from fundamental and applied research and advances through genetic engineering, are expected to increase the use and efficiency of these biotechnological processes.

Numerical Study of the Reduction Process in an Oxygen Blast Furnace

NASA Astrophysics Data System (ADS)

Zhang, Zongliang; Meng, Jiale; Guo, Lei; Guo, Zhancheng

2016-02-01

Based on computational fluid dynamics, chemical reaction kinetics, principles of transfer in metallurgy, and other principles, a multi-fluid model for a traditional blast furnace was established. The furnace conditions were simulated with this multi-fluid mathematical model, and the model was verified with the comparison of calculation and measurement. Then a multi-fluid model for an oxygen blast furnace in the gasifier-full oxygen blast furnace process was established based on this traditional blast furnace model. With the established multi-fluid model for an oxygen blast furnace, the basic characteristics of iron ore reduction process in the oxygen blast furnace were summarized, including the changing process of the iron ore reduction degree and the compositions of the burden, etc. The study found that compared to the traditional blast furnace, the magnetite reserve zone in the furnace shaft under oxygen blast furnace condition was significantly reduced, which is conducive to the efficient operation of blast furnace. In order to optimize the oxygen blast furnace design and operating parameters, the iron ore reduction process in the oxygen blast furnace was researched under different shaft tuyere positions, different recycling gas temperatures, and different allocation ratios of recycling gas between the hearth tuyere and the shaft tuyere. The results indicate that these three factors all have a substantial impact on the ore reduction process in the oxygen blast furnace. Moderate shaft tuyere position, high recycling gas temperature, and high recycling gas allocation ratio between hearth and shaft could significantly promote the reduction of iron ore, reduce the scope of the magnetite reserve zone, and improve the performance of oxygen blast furnace. Based on the above findings, the recommendations for improvement of the oxygen blast furnace design and operation were proposed.

Stable mercury isotope ratios as tracers for Hg cycling at the inoperative New Idria Hg mine, California

NASA Astrophysics Data System (ADS)

Wiederhold, J. G.; Jew, A. D.; Brown, G. E.; Bourdon, B.; Kretzschmar, R.

2010-12-01

The seven stable isotopes of Hg are fractionated in the environment as a result of mass-dependent (MDF) and mass-independent (MIF) fractionation processes that can be studied in parallel by analyzing the ratios of even and odd mass Hg isotopes. MDF and MIF Hg isotope signatures of natural samples may provide a new tool to trace sources and transformations in environmental Hg cycling. However, the mechanisms controlling the extent of kinetic and equilibrium Hg isotope fractionations are still only partially understood. Thus, development of this promising tracer requires experimental calibration of relevant fractionation factors as well as assessment of natural variations of Hg isotope ratios under different environmental conditions. The inoperative Hg mine in New Idria (California, USA) represents an ideal case study to explore Hg isotope fractionation during Hg transformation and transport processes. More than a century of Hg mining and on-site thermal refining to obtain elemental Hg until 1972 produced large volumes of contaminated mine wastes which now represent sources of Hg pollution for the surrounding ecosystems. Here, we present Hg isotope data from various materials collected at New Idria using Cold-Vapor-MC-ICPMS with a long-term δ202Hg reproducibility of ±0.1‰ (2SD). Uncalcined mine waste samples were isotopically similar to NIST-3133 and did not exhibit any MIF signatures. In contrast, calcine samples, which represent the residue of the thermal ore processing at 700°C, had significantly heavier δ202Hg values of up to +1.5‰. In addition, we observed small negative MIF anomalies of the odd-mass Hg isotopes in the calcine samples, which could be caused either by nuclear volume fractionation or a magnetic isotope effect during or after the roasting process. The mass-dependent enrichment of heavy Hg isotopes in the calcine materials indicates that light Hg isotopes were preferentially removed during the roasting process, in agreement with a previous study by Stetson et al. (ES&T, 2009, 43:7331-7336). In order to further elucidate the Hg isotope signatures of the New Idria samples, we performed a three-step sequential extraction procedure to separate different Hg pools. The calcine samples exhibited a higher proportion of leachable Hg phases compared with the unrefined ore waste samples. The most soluble Hg pool (HAc/HCl, pH 2) had a significantly heavier MDF and more negative MIF signature than the bulk calcine samples, suggesting that the dissolution of more soluble Hg phases from calcine materials results in an enhanced flux of leached Hg which is isotopically distinct from the original ore. Moreover, this finding demonstrates that the Hg isotope fractionation during the ore roasting cannot be solely explained by a kinetic Rayleigh-type process which removes light Hg isotopes, but must additionally involve the formation of isotopically heavy secondary Hg phases in the calcine. The analysis of additional samples will enable us to test this hypothesis and to gain further insights into the applicability of stable Hg isotope ratios as source and process tracers in Hg-contaminated environments.

Geophysical exploration of historical mine dumps for the estimation of valuable residuals

NASA Astrophysics Data System (ADS)

Martin, Tina; Knieß, Rudolf; Noell, Ursula; Hupfer, Sarah; Kuhn, Kerstin; Günther, Thomas

2015-04-01

Within the project ROBEHA, funded by the German Federal Ministry of Education and Research (033R105) the economic potential of different abandoned dump sites for mine waste in the Harz Mountains was investigated. Two different mining dumps were geophysically and mineralogically analysed in order to characterize the mine dump structure and to estimate the volume of the potential recycling material. The geophysical methods comprised geoelectrics, radar, and spectral induced polarization (SIP). One about 100-year old mining dump containing residues from density separated Ag- and Sb-rich Pb (Zn)-gangue ores was investigated in detail. Like most small-scale mining waste disposal sites this investigated dump is very heterogeneously structured. Therefore, 27 geoelectrical profiles, more than 50 radar profiles, and several SIP profiles were measured and analysed. The results from the radar measurements, registered with the GSSI system and a shielded 200 MHz antenna, show the near surface boundary layer (down to 3-4 m beneath surface) of the waste residuals. These results can be used as pre-information for the inversion process of the geoelectrical data. The geoelectrical results reveal the mineral residues as layers with higher resistivities (> 300 Ohm*m) than the surrounding material. The SIP method found low phase signals (< 0.5°) for the residues. To estimate the volume of the potentially reusable material we analysed each geoelectrical profile and interpolated between the single profiles using the BERT algorithm. Taking into account the wooded areas of the mine dump and other parameters we get a first estimate for the volume of the residues but the economical viability and the environmental impact of the reworking of the dump still needs to be evaluated in detail. The results of the second mine dump, an abandoned Cu and Zn-rich slag heap, show that the slag residues are characterized by higher resistivities and higher phases. A localization of the slag residues which are covered by organic material could be realized applying these geophysical methods.

Influence of organic waste and residue mud additions on chemical, physical and microbial properties of bauxite residue sand.

PubMed

Jones, Benjamin E H; Haynes, Richard J; Phillips, Ian R

2011-02-01

In an alumina refinery, bauxite ore is treated with sodium hydroxide at high temperatures and pressures and for every tone of alumina produced, about 2 tones of alkaline, saline bauxite processing waste is also produced. At Alcoa, a dry stacking system of disposal is used, and it is the sand fraction of the processing waste that is rehabilitated. There is little information available regarding the most appropriate amendments to add to the processing sand to aid in revegetation. The purpose of this study was to investigate how the addition of organic wastes (biosolids and poultry manure), in the presence or absence of added residue mud, would affect the properties of the residue sand and its suitability for revegetation. Samples of freshly deposited residue sand were collected from Alcoa's Kwinana refinery. Samples were treated with phosphogypsum (2% v/v), incubated, and leached. A laboratory experiment was then set up in which the two organic wastes were applied at 0 or the equivalent to 60 tones ha(-1) in combination with residue mud added at rates of 0%, 10% and 20% v/v. Samples were incubated for 8 weeks, after which, key chemical, physical and microbial properties of the residue sand were measured along with seed germination. Additions of residue mud increased exchangeable Na(+), ESP and the pH, and HCO (3) (-) and Na(+) concentrations in saturation paste extracts. Additions of biosolids and poultry manure increased concentrations of extractable P, NH (4) (+) , K, Mg, Cu, Zn, Mn and Fe. Addition of residue mud, in combination with organic wastes, caused a marked decrease in macroporosity and a concomitant increase in mesoporosity, available water holding capacity and the quantity of water held at field capacity. With increasing residue mud additions, the percentage of sample present as sand particles (<1 mm diameter) decreased, and the percentage present in aggregated form (>2 mm diameter) increased; greatest aggregation occurred where a combination of residue mud and poultry manure were added. Stability of aggregates, as measured by wet sieving, was greatest where poultry manure was applied. Although total organic C and soluble organic C were greater in biosolids than poultry manure treatments, the reverse was the case for microbial biomass C and basal respiration. In the biosolids and poultry manure treatments, increasing residue mud additions tended to increase soluble C, microbial biomass C and basal respiration. Germination index of watercress was highest in control samples and reduced by additions of biosolids and poultry manure which was attributed to the high EC and possibly high extractable P and NH (4) (+) . The concurrent addition of residue mud and organic wastes can improve chemical, microbial and particularly physical properties of residue sand. Future research should include neutralisation of the mud (e.g. with gypsum) and subsequent leaching to remove salts originating from both the mud and organic wastes.

Review of Manganese Processing for Production of TRIP/TWIP Steels, Part 2: Reduction Studies

NASA Astrophysics Data System (ADS)

Elliott, R.; Coley, K.; Mostaghel, S.; Barati, M.

2018-02-01

Production of ultrahigh-manganese steels is expected to result in significant increase in demand for low-carbon (LC) ferromanganese (FeMn) and silicomanganese (SiMn). Current manganese processing techniques are energy intensive and typically yield a high-carbon product. The present work therefore reviews available literature regarding carbothermic reduction of Mn oxides and ores, with the objective of identifying opportunities for future process development to mitigate the cost of LC FeMn and SiMn. In general, there is consensus that carbothermic reduction of Mn oxides and ores is limited by gasification of carbon. Conditions which enhance or bypass this step (e.g., by application of CH4) show higher rates of reduction at lower temperatures. This phenomenon has potential application in solid-state reduction of Mn ore. Other avenues for process development include optimization of the prereduction step in conventional FeMn production and metallothermic reduction as a secondary reduction step.

Mining and beneficiation of lunar ores

NASA Technical Reports Server (NTRS)

Bunch, T. E.; Williams, R. J.; Mckay, D. S.; Giles, D.

1979-01-01

The beneficiation of lunar plagioclase and ilmenite ores to feedstock grade permits a rapid growth of the space manufacturing economy by maximizing the production rate of metals and oxygen. A beneficiation scheme based on electrostatic and magnetic separation is preferred over conventional schemes, but such a scheme cannot be completely modeled because beneficiation processes are empirical and because some properties of lunar minerals have not been measured. To meet anticipated shipping and processing needs, the peak lunar mining rate will exceed 1000 tons/hr by the fifth year of operation. Such capabilities will be best obtained by automated mining vehicles and conveyor systems rather than trucks. It may be possible to extract about 40 kg of volatiles (60 percent H2O) by thermally processing the less than 20 micron ilmenite concentrate extracted from 130 tons of ilmenite ore. A thermodynamic analysis of an extraction process is presented.

Investigation of the environmental impacts of naturally occurring radionuclides in the processing of sulfide ores for gold using gamma spectrometry.

PubMed

Gbadago, J K; Faanhof, A; Darko, E O; Schandorf, C

2011-09-01

The possible environmental impacts of naturally occurring radionuclides on workers and a critical community, as a result of milling and processing sulfide ores for gold by a mining company at Bogoso in the western region of Ghana, have been investigated using gamma spectroscopy. Indicative doses for the workers during sulfide ore processing were calculated from the activity concentrations measured at both physical and chemical processing stages. The dose rate, annual effective dose equivalent, radium equivalent activity, external and internal hazard indices, and radioactivity level index for tailings, for the de-silted sediments of run-off from the vicinity of the tailings dam through the critical community, and for the soils of the critical community's basic schools were calculated and found to be lower than their respective permissible limits. The environmental impact of the radionuclides is therefore expected to be low in this mining environment.

Time-Variant Reliability Analysis for Rubber O-Ring Seal Considering Both Material Degradation and Random Load

PubMed Central

Liao, Baopeng; Yan, Meichen; Zhang, Weifang; Zhou, Kun

2017-01-01

Due to the increase in working hours, the reliability of rubber O-ring seals used in hydraulic systems of transfer machines will change. While traditional methods can only analyze one of the material properties or seal properties, the failure of the O-ring is caused by these two factors together. In this paper, two factors are mainly analyzed: the degradation of material properties and load randomization by processing technology. Firstly, the two factors are defined in terms of material failure and seal failure, before the experimental methods of rubber materials are studied. Following this, the time-variant material properties through experiments and load distribution by monitoring the processing can be obtained. Thirdly, compressive stress and contact stress have been calculated, which was combined with the reliability model to acquire the time-variant reliability for the O-ring. Finally, the life prediction and effect of oil pressure were discussed, then compared with the actual situation. The results show a lifetime of 12 months for the O-ring calculated in this paper, and compared with the replacement records from the maintenance workshop, the result is credible. PMID:29053597

EXTRACTION OF URANIUM

DOEpatents

Kesler, R.D.; Rabb, D.D.

1959-07-28

An improved process is presented for recovering uranium from a carnotite ore. In the improved process U/sub 2/O/sub 5/ is added to the comminuted ore along with the usual amount of NaCl prior to roasting. The amount of U/sub 2/O/ sub 5/ is dependent on the amount of free calcium oxide and the uranium in the ore. Specifically, the desirable amount of U/sub 2/O/sub 5/ is 3.2% for each 1% of CaO, and 5 to 6% for each 1% of uranium. The mixture is roasted at about 1560 deg C for about 30 min and then leached with a 3 to 9% aqueous solution of sodium carbonate.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

NASA Astrophysics Data System (ADS)

Smith, Christopher N.; Kesler, Stephen E.; Blum, Joel D.; Rytuba, James J.

2008-05-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300 m) and silica-carbonate deposits that extend to depths of 1000 m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions ( δ202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although δ202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean δ202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ± 0.5‰) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO 2 vapor or reduction and volatilization of Hg (0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low δ202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems.

Isotope geochemistry of mercury in source rocks, mineral deposits and spring deposits of the California Coast Ranges, USA

USGS Publications Warehouse

Smith, C.N.; Kesler, S.E.; Blum, J.D.; Rytuba, J.J.

2008-01-01

We present here the first study of the isotopic composition of mercury in rocks, ore deposits, and active spring deposits from the California Coast Ranges, a part of Earth's crust with unusually extensive evidence of mercury mobility and enrichment. The Franciscan Complex and Great Valley Sequence, which form the bedrock in the California Coast Ranges, are intruded and overlain by Tertiary volcanic rocks including the Clear Lake Volcanic Sequence. These rocks contain two types of mercury deposits, hot-spring deposits that form at shallow depths (< 300??m) and silica-carbonate deposits that extend to depths of 1000??m. Active springs and geothermal areas continue to precipitate Hg and Au and are modern analogues to the fossil hydrothermal systems preserved in the ore deposits. The Franciscan Complex and Great Valley Sequence contain clastic sedimentary rocks with higher concentrations of mercury than volcanic rocks of the Clear Lake Volcanic Field. Mean mercury isotopic compositions (??202Hg) for all three rock units are similar, although the range of values in Franciscan Complex rocks is greater than in either Great Valley or Clear Lake rocks. Hot spring and silica-carbonate mercury deposits have similar average mercury isotopic compositions that are indistinguishable from averages for the three rock units, although ??202Hg values for the mercury deposits have a greater variance than the country rocks. Precipitates from spring and geothermal waters in the area have similarly large variance and a mean ??202Hg value that is significantly lower than the ore deposits and rocks. These observations indicate that there is little or no isotopic fractionation (< ?? 0.5???) during release of mercury from its source rocks into hydrothermal solutions. Isotopic fractionation does appear to take place during transport and concentration of mercury in deposits, however, especially in their uppermost parts. Boiling of hydrothermal fluids, separation of a mercury-bearing CO2 vapor or reduction and volatilization of Hg(0) in the near-surface environment are likely the most important processes causing the observed Hg isotope fractionation. This should result in the release of mercury with low ??202Hg values into the atmosphere from the top of these hydrothermal systems. Estimates of mass balance suggest that residual Hg reservoirs are not measurably enriched in heavy Hg isotopes as a result of this process because only a small amount of Hg (< 4%) leaves actively ore-forming systems. ?? 2008 Elsevier B.V. All rights reserved.

On diagenesis, dolomitisation and mineralisation in the Irish Zn-Pb orefield

NASA Astrophysics Data System (ADS)

Wilkinson, Jamie J.

2003-12-01

Marine calcite cementation and lithification of Carboniferous carbonate sediments hosting Zn-Pb mineralisation in the Irish orefield occurred at or near the seafloor. A relatively early, fine-grained, grey replacive dolomite, preferentially developed in micrite, is widely developed in the Waulsortian Limestone Formation, the main host to mineralisation, and is pervasive in the southeastern Midlands in proximity to the Leinster Massif. This dolomite formed after the first four main stages of calcite cementation but probably also developed within tens of metres of the seafloor as evidenced by incorporation of clasts of dolomite in intraformational sedimentary breccias. Later, coarse-grained white dolomite preferentially replaced coarser components of the Waulsortian Limestone and infilled residual vuggy porosity. Whilst some of this coarse dolomite may be related to the fine replacive dolomite event, a common spatial association with fault zones, coupled with primary fluid inclusion data, suggest that a significant proportion of this phase precipitated during the onset of fault-controlled subsidence and widespread hydrothermal circulation within the Irish Midlands area. Fluids up to ~250 °C and 10-15 wt% NaCl equivalent, sourced from a Lower Palaeozoic basement-equilibrated fluid reservoir, infiltrated the carbonate sequence via faults and fractures. The more localised development of dolomite-cemented breccias (white matrix breccias) that are frequently associated spatially with mineralisation was a consequence of the increased focusing of these hydrothermal fluids. Ore formation was broadly synchronous with development of the white dolomite breccias but only happened where mixing occurred between the hydrothermal ore-fluids and localised, near-surface reservoirs of low-temperature, H2S-rich brine. In the Waulsortian, this process led to the precipitation of a distinctive black dolomite that forms a broad halo to massive sulphides. Although ore-stage sulphides postdate significant diagenesis of the host rocks, and often display "epigenetic" textures, the fact that much of the cementation occurred soon after carbonate deposition means that mineralisation does not have to have formed after significant burial. In fact, the occurrence of clasts of hydrothermal dolomite and sulphides in intraformational debris-flow breccias is only consistent with mineralising processes occurring in the near-seafloor environment, relatively soon after host-rock deposition. The regional development of a distinctive pink dolomite associated with faults and fractures was a post-ore event, and is considered to mark a regional brine migration linked to the onset of the Variscan orogeny. The development of this new tectonic and flow regime may have been responsible for the cessation of economic mineralisation in Ireland.

Developmental Origins of the Other-Race Effect

PubMed Central

Anzures, Gizelle; Quinn, Paul C.; Pascalis, Olivier; Slater, Alan M.; Tanaka, James W.; Lee, Kang

2013-01-01

The other-race effect (ORE) in face recognition refers to better recognition memory for faces of one’s own race than faces of another race—a common phenomenon among individuals living in primarily mono-racial societies. In this article, we review findings suggesting that early visual and sociocultural experiences shape one’s processing of familiar and unfamiliar race classes and give rise to the ORE within the 1st year of life. However, despite its early development, the ORE can be prevented, attenuated, and even reversed given experience with a novel race class. Social implications of the ORE are discussed in relation to development of race-based preferences for social partners and racial prejudices. PMID:24049246

Constitutive mass balance relations between chemical composition, volume, density, porosity, and strain in metasomatic hydrochemical systems: Results on weathering and pedogenesis

NASA Astrophysics Data System (ADS)

Brimhall, George H.; Dietrich, William E.

1987-03-01

Relations characterizing the chemical, physical, and mechanical changes resulting from metasomatic hydrochemical processes are developed using mass balance models which formally link chemical composition to bulk density, mineral density, volumetric properties, porosity, and amount of deformation (strain). Rigorous analysis of aqueous solute transport effects is then made possible in a variety of porous media flow environments including chemical weathering, pedogenesis (soil formation), diagenesis, ore deposition and enrichment, and metamorphism. Application of these linear constitutive relations to chemical weathering profiles shows that immobile and locally mobile chemical elements, with masses conserved on the scale of soil profiles, can be accurately identified from analysis of appropriate data arrays and then used as natural geochemical tracers to infer the nature and extent of hydrochemical weathering processes and volume changes during pedogenesis. Assumptions commonly made in the past about the supposed immobility of certain elements, e.g., Ti and Zr, become unnecessary. Quantitative differentiation between the effects of residual and supergene fractionation is then easily made. These methods are applied to Ni-rich laterites developed by weathering of ultramafic rocks, showing that during ordinary residual enrichment, Ni is concentrated by as much as 4× protolith peridotite concentrations. This occurs simply by silicate mineral dissolution and removal of chemical elements other than Ni ( e.g., Mg) with a corresponding reduction in saprolite density and increase in bulk porosity without significant deformation. In contrast, laterites with mineable concentrations of Ni which are similarly undeformed (such as the Nickel Mountain Mine in Riddle, Oregon) have experienced, in addition to residual enrichment, strong supergene enrichment by fractionation of ore elements between a leached zone from which Ni is extracted and a complementary enriched zone positioned farther along the direction of ground water flow. Soil-forming processes in podzol chronosequences developed on sandy beach terraces of the Mendocino Coast of California involved soil column collapse of 60 percent by dissolution of silicate minerals in the albic horizon of Al and Fe leaching, and 70 percent dilation (expansion) in the overlying organic-rich layer by root growth. The amount of erosion based upon paleosurface reconstructions using the excess mass of Fe, Al, Pb, Ga, and Cu in the zone of supergene enrichment (spodic horizon) below the ground water table indicates that subsurface erosion by dissolutional collapse is three times that of surficial erosion. Finally, using published chemical data for Ti, Zr, and Cr on major bauxite deposits in Australia where erosion rates are thought to be low, we infer that there may have been major amounts of dissolutional collapse to explain the upwards increase of detrital zircon and rutile in weathering profiles.

Late-stage sulfides and sulfarsenides in Lower Cambrian black shale (stone coal) from the Huangjiawan mine, Guizhou Province, People's Republic of China

USGS Publications Warehouse

Belkin, H.E.; Luo, K.

2008-01-01

The Ni-Mo Huangjiawan mine, Guizhou Province, People's Republic of China, occurs in Lower Cambrian black shale (stone coal) in an area where other mines have recently extracted ore from the same horizon. Detailed electron microprobe (EMPA) and scanning electron microscope (SEM) analyses of representative thin sections have revealed a complex assemblage of sulfides and sulfarsenides. Early sulfidic and phosphatic nodules and host matrix have been lithified, somewhat fractured, and then mineralized with later-stage sulfides and sulfarsenides. Gersdorffite, millerite, polydymite, pyrite, sphalerite, chalcopyrite, galena, and clausthalite have been recognized. EMPA data are given for the major phases. Pyrite trace-element distributions and coeval Ni-, As-sulfides indicate that in the main ore layer, the last sulfide deposition was Ni-As-Co-rich. Mo and V deposition were early in the petrogenesis of these rocks. The assemblages gersdorffite-millerite-polydymite (pyrite) and millerite-gersdorffite (pyrite) and the composition of gersdorffite indicate a formation temperature of between 200?? and 300??C suggesting that the last solutions to infiltrate and mineralize the samples were related to hydrothermal processes. Environmentally sensitive elements such as As, Cd, and Se are hosted by sulfides and sulfarsenides and are the main source of these elements to residual soil. Crops grown on them are enriched in these elements, and they may be hazardous for animal and human consumption. ?? Springer-Verlag 2007.

Static Thermochemical Model of COREX Melter Gasifier

NASA Astrophysics Data System (ADS)

Srishilan, C.; Shukla, Ajay Kumar

2018-02-01

COREX is one of the commercial smelting reduction processes. It uses the finer size ore and semi-soft coal instead of metallurgical coke to produce hot metal from iron ore. The use of top gas with high calorific value as a by-product export gas makes the process economical and green. The predictive thermochemical model of the COREX process presented here enables rapid computation of process parameters such as (1) required amount of ore, coal, and flux; (2) amount of slag and gas generated; and (3) gas compositions (based on the raw material and desired hot metal quality). The model helps in predicting the variations in process parameters with respect to the (1) degree of metallization and (2) post-combustion ratio for given raw material conditions. In general reduction in coal, flux, and oxygen, the requirement is concomitant with an increase in the degree of metallization and post-combustion ratio. The model reported here has been benchmarked using industrial data obtained from the JSW Steel Plant, India.

A Comparison of the Greenhouse Impacts of Magnesium Produced By Electrolytic and Pidgeon Processes

NASA Astrophysics Data System (ADS)

Ramakrishnan, Subramania; Koltun, Paul

With a focus on the global warming impact, this paper deals with the cradle-to-gate life cycle study of the following two practical production systems for producing magnesium ingots: (i) Magnesite ore is processed using the Australian Magnesium process to produce anhydrous magnesium chloride, which is then electrolysed to produce magnesium; and (ii) Dolomite ore is calcined to produce magnesium oxide, which is then thermally reduced with ferrosilicon using the Pidgeon process, based on the current practice used in China for magnesium production

Recovery of Manganese Ore Tailings by High-Gradient Magnetic Separation and Hydrometallurgical Method

NASA Astrophysics Data System (ADS)

Zhang, Xiufeng; Tan, Xiumin; Yi, Yuejun; Liu, Weizao; Li, Chun

2017-11-01

With the depletion of high-grade manganese ores, Mn ore tailings are considered valuable secondary resources. In this study, a process combining high-gradient magnetic separation (HGMS) with hydrometallurgical methods is proposed to recycle fine-grained Mn tailings. The Mn tailings were treated by HGMS at 12,500 G to obtain a Mn concentrate of 30% Mn with the recovery efficiency of 64%. The Mn concentrate could be used in the ferromanganese industry. To recover Mn further, the nonmagnetic fraction was leached by SO2 in an H2SO4 solution. Hydrogen peroxide was added to the leachate to oxidize Fe2+ to Fe3+, and the solution pH was adjusted to 5.0-5.5 with ammonia to remove Al, Fe, and Si impurities. The purified solution was reacted with NH4HCO3, and a saleable product of MnCO3 with 97.9% purity was obtained. The combined process can be applied to Mn recovery from finely dispersed weakly magnetic Mn ores or tailings.

ALKALINE CARBONATE LEACHING PROCESS FOR URANIUM EXTRACTION

DOEpatents

Thunaes, A.; Brown, E.A.; Rabbitts, A.T.

1957-11-12

A process for the leaching of uranium from high carbonate ores is presented. According to the process, the ore is leached at a temperature of about 200 deg C and a pressure of about 200 p.s.i.g. with a solution containing alkali carbonate, alkali permanganate, and bicarbonate ion, the bicarbonate ion functionlng to prevent premature formation of alkali hydroxide and consequent precipitation of a diuranate. After the leaching is complete, the uranium present is recovered by precipitation with NaOH.

Getty Oil Company Diatomite project

DOE Office of Scientific and Technical Information (OSTI.GOV)

Zuber, I.L.

1984-09-01

The feasibility of using Diatomite as a synthetic fuels feedstock is discussed. The asphaltic outcropping near McKittrick, California are evidence of oil bearing deposits. Two different processes have been taken to the pilot plant stage to evaluate the viability of recovering oil from the Diatomite ore. One approach was the retorting process which was developed by Lurgi. The other process is based on a totally different concept of solvent extracting the oil from the ore. The operation and performance of the pilot plants are described.

SOLVENT EXTRACTION PROCESS FOR URANIUM RECOVERY

DOEpatents

Clark, H.M.; Duffey, D.

1958-06-17

A process is described for extracting uranium from uranium ore, wherein the uranium is substantially free from molybdenum contamination. In a solvent extraction process for recovering uranium, uranium and molybdenum ions are extracted from the ore with ether under high acidity conditions. The ether phase is then stripped with water at a lower controiled acidity, resaturated with salting materials such as sodium nitrate, and reextracted with the separation of the molybdenum from the uranium without interference from other metals that have been previously extracted.

Long-term surveillance plan for the Bodo Canyon Disposal Site, Durango, Colorado

DOE Office of Scientific and Technical Information (OSTI.GOV)

Not Available

1994-03-01

This long-term surveillance plan (LTSP) for the Durango, Colorado, Uranium Mill Tailings Remedial Action (UMTRA) Project disposal site describes the surveillance activities for the Durango (Bodo Canyon) disposal site, which will be referred to as the disposal site throughout this document. The US Department of Energy (DOE) will carry out these activities to ensure that the disposal site continues to function as designed. This LTSP was prepared as a requirement for acceptance under the US Nuclear Regulatory Commission (NRC) general license for custody and long-term care of residual radioactive materials (RRM). RRMs include tailings and other uranium ore processing wastesmore » still at the site, which the DOE determines to be radioactive. This LTSP is based on the DOE`s Guidance for Implementing the UMTRA Project Long-term Surveillance Program (DOE, 1992).« less

Possibilities of magnetotelluric methods in geophysical exploration for ore minerals

NASA Astrophysics Data System (ADS)

Varentsov M., Iv.; Kulikov, V. A.; Yakovlev, A. G.; Yakovlev, D. V.

2013-05-01

In the past decade, the applications of magnetotelluric method in the electric prospecting for ore bodies have been rapidly progressing. In the present work, we summarize the first results on this way. We discuss the specificity of the geoelectrical models in the problems of mining prospecting for ore bodies. The state-of-the-art capabilities of the method, which rely on the synchronous observation systems and the procedure of joint inversion of magnetotelluric and magnetovariational responses, are considered in the context of ore mineral exploration. The results of modeling a typical mining audio-magnetotelluric survey for ore minerals are presented. On the basis of these simulations and the data provided by in-situ soundings, the efficient approaches to the processing, analysis, and inversion of these data are discussed and illustrated. The future trends in magnetotellurics as applied to the mining prospecting are analyzed.

Mössbauer analysis of BIOX treatment of ores at Wiluna gold mine, Western Australia

NASA Astrophysics Data System (ADS)

Gagliardi, F. M.; Cashion, J. D.

2013-04-01

Mössbauer phase analysis of samples taken from nine stages of the bacterial oxidation processing of gold ore at the Wiluna Gold Mine followed the transformation of the arsenopyrite/pyrite minerals. The principal end-stage phases were szomolnokite, ferric oxyhydroxides, ferric arsenates, jarosite and incompletely transformed pyrite, with higher hydrates of ferrous sulphate being created and then dehydrating to szomolnokite during the processing.

Solid residues from Italian municipal solid waste incinerators: A source for "critical" raw materials.

PubMed

Funari, Valerio; Braga, Roberto; Bokhari, Syed Nadeem Hussain; Dinelli, Enrico; Meisel, Thomas

2015-11-01

The incineration of municipal solid wastes is an important part of the waste management system along with recycling and waste disposal, and the solid residues produced after the thermal process have received attention for environmental concerns and the recovery of valuable metals. This study focuses on the Critical Raw Materials (CRM) content in solid residues from two Italian municipal waste incinerator (MSWI) plants. We sampled untreated bottom ash and fly ash residues, i.e. the two main outputs of common grate-furnace incinerators, and determined their total elemental composition with sensitive analytical techniques such as XRF and ICP-MS. After the removal of a few coarse metallic objects from bottom ashes, the corresponding ICP solutions were obtained using strong digestion methods, to ensure the dissolution of the most refractory components that could host significant amounts of precious metals and CRM. The integration of accurate chemical data with a substance flow analysis, which takes into account the mass balance and uncertainties assessment, indicates that bottom and fly ashes can be considered as a low concentration stream of precious and high-tech metals. The magnesium, copper, antimony and zinc contents are close to the corresponding values of a low-grade ore. The distribution of the elements flow between bottom and fly ash, and within different grain size fractions of bottom ash, is appraised. Most elements are enriched in the bottom ash flow, especially in the fine grained fractions. However, the calculated transfer coefficients indicate that Sb and Zn strongly partition into the fly ashes. The comparison with available studies indicates that the CRM concentrations in the untreated solid residues are comparable with those residues that undergo post-treatment beneficiations, e.g. separation between ferrous and non-ferrous fractions. The suggested separate collection of "fresh" bottom ash, which could be processed for further mineral upgrading, can constitute an attractive option of the waste management system, when physical-mechanical devices are not available or could not be implemented in old MSWI systems. The suggested procedure may lead to the improvement of recovery efficiency up to 83% for CRM and 94% for other valuable metals. Copyright © 2014 Elsevier Ltd. All rights reserved.

Fractionation and leachability of heavy metals from aged and recent Zn metallurgical leach residues from the Três Marias zinc plant (Minas Gerais, Brazil).

PubMed

Sethurajan, Manivannan; Huguenot, David; Lens, Piet N L; Horn, Heinrich A; Figueiredo, Luiz H A; van Hullebusch, Eric D

2016-04-01

Various mineral processing operations to produce pure metals from mineral ores generate sludges, residues, and other unwanted by-products/wastes. As a general practice, these wastes are either stored in a reservoir or disposed in the surrounding of mining/smelting areas, which might cause adverse environmental impacts. Therefore, it is important to understand the various characteristics like heavy metal leaching features and potential toxicity of these metallurgical wastes. In this study, zinc plant leach residues (ZLRs) were collected from a currently operating Zn metallurgical industry located in Minas Gerais (Brazil) and investigated for their potential toxicity, fractionation, and leachability. Three different ZLR samples (ZLR1, ZLR2, and ZLR3) were collected, based on their age of production and deposition. They mainly consisted of Fe (6-11.5 %), Zn (2.5 to 5.0 %), and Pb (1.5 to 2.5 %) and minor concentrations of Al, Cd, Cu, and Mn, depending on the sample age. Toxicity Characteristic Leaching Procedure (TCLP) results revealed that these wastes are hazardous for the environment. Accelerated Community Bureau of Reference (BCR) sequential extraction clearly showed that potentially toxic heavy metals such as Cd, Cu, Pb, and Zn can be released into the environment in high quantities under mild acidic conditions. The results of the liquid-solid partitioning as a function of pH showed that pH plays an important role in the leachability of metals from these residues. At low pH (pH 2.5), high concentrations of metals can be leached: 67, 25, and 7 % of Zn can be leached from leach residues ZLR1, ZLR2, and ZLR3, respectively. The release of metals decreased with increasing pH. Geochemical modeling of the pH-dependent leaching was also performed to determine which geochemical process controls the leachability/solubility of the heavy metals. This study showed that the studied ZLRs contain significant concentrations of non-residual extractable fractions of Zn and can be seen as a potential secondary resource for Zn.

Water requirements of the iron and steel industry

USGS Publications Warehouse

Walling, Faulkner B.; Otts, Louis Ethelbert

1967-01-01

Twenty-nine steel plants surveyed during 1957 and 1958 withdrew from various sources about 1,400 billion gallons of water annually and produced 40.8 million tons of ingot steel. This is equivalent to about 34,000 gallons of water per ton of steel. Fifteen iron ore mines and fifteen ore concentration plants together withdrew annually about 89,000 million gallons to produce 15 million tons of iron ore concentrate, or 5,900 gallons per ton of concentrate. About 97 percent of the water used in the steel plants came from surface sources, 2.2 percent was reclaimed sewage, and 1.2 percent was ground water. Steel plants supplied about 96 percent of their own water requirements, although only three plants used self-supplied water exclusively. Water used by the iron ore mines and concentration plants was also predominantly self supplied from surface source. Water use in the iron and steel industry varied widely and depended on the availability of water, age and condition of plants and equipment, kinds of processes, and plant operating procedures. Gross water use in integrated steel plants ranged from 11,200 to 110,000 gallons per ton of steel ingots, and in steel processing plants it ranged from 4,180 to 26,700 gallons per ton. Water reuse also varied widely from 0 to 18 times in integrated steel plants and from 0 to 44 times in steel processing plants. Availability of water seemed to be the principal factor in determining the rate of reuse. Of the units within steel plants, a typical (median) blast furnace required 20,500 gallons of water per ton of pig iron. At the 1956-60 average rate of pig iron consumption, this amounts to about 13,000 gallons per ton of steel ingots or about 40 percent of that required by a typical integrated steel plant 33,200 gallons per ton. Different processes of iron ore concentration are devised specifically for the various kinds of ore. These processes result in a wide range of water use from 124 to 11,300 gallons of water per ton of iron ore concentrate. Water use in concentration plants is related to the physical state of the ore. The data in this report indicate that grain size of the ore is the most important factor; the very fine grained taconite and jasper required the greatest amount of water. Reuse was not widely practiced in the iron ore industry.Consumption of water by integrated steel plants ranged from 0 to 2,010 gallons per ton of ingot steel and by steel processing plants from 120 to 3,420 gallons per ton. Consumption by a typical integrated steel plant was 681 gallons per ton of ingot steel, about 1.8 percent of the intake and about 1 percent of the gross water use. Consumption by a typical steel processing plant was 646 gallons per ton, 18 percent of the intake, and 3.2 percent of the gross water use. The quality of available water was found not to be a critical factor in choosing the location of steel plants, although changes in equipment and in operating procedures are necessary when poor-quality water is used. The use of saline water having a concentration of dissolved solids as much as 10,400 ppm (parts per million) was reported. This very saline water was used for cooling furnaces and for quenching slag. In operations such as rolling steel in which the water comes into contact with the steel being processed, better quality water is used, although water containing as much as 3,410 ppm dissolved solids has been used for this purpose. Treatment of water for use in the iron and steel industry was not widely practiced. Disinfection and treatment for scale and corrosion control were the most frequently used treatment methods.

The role of metasomatism in the balance of halogens in ore-forming process at porphyry Cu-Mo deposits

NASA Astrophysics Data System (ADS)

Berzina, A. N.

2009-04-01

Volatile components play an important role in the evolution of ore-magmatic systems and their ore potential. Of special interest are fluorine and chlorine compounds that principally control the transportation of ore elements by the fluid in a magmatic process and under high-temperature hydrothermal conditions. Study of the evolution of fluorine-chlorine activity in the ore-forming process and their source is usually based on analysis of their magmatic history, whereas the additional source of fluorine and chlorine released during metasomatic alteration of rocks hosting mineralization is poorly discussed in the existing literature. Based on microprobe data on Cl and F abundances in halogen-containing minerals (biotite, amphibole, apatite, titanite) in intrusive rocks and their hydrothermally altered varieties, the role of metasomatic processes in the balance of volatiles in the ore-forming system is discussed by the example of porphyry Cu-Mo deposits of Siberia (Russia) and Mongolia. Two groups of the deposits are considered: copper-molybdenum (Erdenetiin Ovoo, Mongolia and Aksug, Russia) with prevailing propylitic and phyllic alteration and molybdenum-copper (Sora, Russia), with predominant potassic alteration. All types of hydrothermal alterations have led to drastic decrease in Cl contents in metasomatic minerals as compared with halogen-containing magmatic minerals. All studied deposits (particularly those where propylitic and phyllic alteration were developed) show a nearly complete chlorine removal from altered halogen-containing rock-forming minerals (biotite and amphibole). The Cl content in amphibole decreases several times at the stage of replacement with actinolite in the process of propylitization. In the later chlorites (ripidolite and brunsvigite) that replace amphibole, actinolite, and biotite, chlorine is not detected by microprobe (detection limit 0.01-0.02% Cl). Chlorine was also not detected in white micas (muscovite-phengite series) in quartz-sericite alteration zones. No Cl-bearing minerals were revealed in ore-metasomatic assemblages with the exception of extremely low Cl contents in secondary biotite and very rare low-Cl apatite in the early potassic alteration zone. In contrast, fluorine concentrates in chlorites and white micas; however, the F content in them is commonly lower than in dark minerals, especially in biotite from altered rocks. The highest F contents are typical of biotites related to potassic alteration (K-feldspar + biotite + quartz assemblage). For example, the F content at the Sora deposit ranges from 2.5-2.7 wt.% in the metasomatic biotite to 0.44-1.63 wt.% in the rock-forming biotite of host granitoids. At this deposit, fluorite is a major mineral of the ore-metasomatic assemblage. The Mo-rich Sora deposit drastically differs from the Cu-rich Erdenetiin Ovoo and Aksug deposits by extremely low (0.02-0.08 wt.%) Cl contents in dark minerals from all of the host rocks. The considerable quantity of chlorine released as a result of large-scale propylitic and phyllic alteration from halogen-bearing dark minerals at Cu-rich deposits considerably affected the general Cl budget in the ore-metasomatic system. This could significantly promote the generation of Cl-rich (up to 50-70 wt.% NaCl-equiv.) ore-forming solutions at such deposits. At the Sora deposit characterized by less concentrated ore-bearing solutions (12-20 wt.% NaCl-equiv.), the metasomatic alteration of host rocks was not accompanied by an appreciable removal of Cl. At the studied deposits, huge volumes of enclosing rocks were involved in metasomatism. The large amounts of halogens released during the metasomatic alteration of host rocks might have significantly influenced the balance of volatiles in the ore forming system, including the increase in the salinity of hydrothermal solutions.

A gallery of oil components, their metals and Re-Os signatures

NASA Astrophysics Data System (ADS)

Stein, Holly J.; Hannah, Judith L.

2016-04-01

Most sediment-hosted metallic ore deposits are one degree of freedom from hydrocarbon. That is, sulfide fluid inclusions may contain vestiges of travel in tandem with hydrocarbon-bearing fluids. For metallic ore deposits of stated metamorphic and magmatic origin, the degrees of freedom are several times more or, in some cases, no relationship exists. Still, the fetish for stereotyping and classifying ore types into hardline ore deposit models (or hybrid models when the data are wildly uncooperative) impedes our ability to move toward a better understanding of source rock. Fluids in the deeper earth, fluids in the crust, and the extraterrestrial rain of metals provide the Re-Os template for oil. So, too, this combination ultimately drives the composition of many metallic ore deposits. The world of crude oil and its complex history of maturation, migration, mixing, metal-rich asphaltene precipitation, and subsequent mobility of lighter and metal-poor components, is an untapped resource for students of ore geology. In the same way that Mississippi Valley-type lead and zinc deposits are described as the outcome of two converging and mixing fluids (metal-bearing and sulfur-bearing fluids), asphaltene precipitation can be an outcome of a lighter oil meeting and mixing with a heavier one. In the petroleum industry, this can spell economic disaster if the pore-space becomes clogged with a non-producible heavy oil or solid bitumen. In ore geology, sulfide precipitation on loss of permeability may create a Pb-Zn deposit. Petroleum systems provide a gallery of successive time-integrated Re-Os results. Heavy or biodegraded oils, if intersected by lighter oil or gas, can generate asphaltite or tar mats, and release a reservoir of still lighter oil (or gas). During this process there are opportunities for separation of metal-enriched aqueous fluids that may retain an imprint of their earlier hydrocarbon history, ultimately trapped in fluid inclusions. Salinity, temperature and pH are part of the equation controlling composition of metal-bearing aqueous fluids siphoned from residual hydrocarbons. The Re-Os isotopic behavior of oil components is generally specific to location and may differ within a single oil field, or even within discrete fractions of a single sample of oil [1]. Different fractions in a crude oil, for example maltenes and asphaltenes, can preserve signatures of unique sources. This should not be surprising, since economic geologists have long called upon meeting and mixing of metal-bearing with sulfur-bearing fluids from different sources. A time-integrated geologic history can also be derived from bitumen veins, with the Re-Os age of the metal source cached in these veins. Preservation of early metal and hydrocarbon history, and intact Re-Os systematics preserved in younger-formed systems have enormous potential for the resource industry. Several examples will be presented. [1] Georgiev, S.V., Stein, H.J., Hannah, J.L., Galimberti, R., Nali, M., Yang, G., and Zimmerman, A. (returned post revision, 11 Jan 2016) Re-Os dating of maltenes and asphaltenes within single samples of crude oils: Geochimica et Comochimica Acta. Supported by a consortium of petroleum companies under the CHRONOS project.

Fluid inclusion gas chemistry as a potential minerals exploration tool: Case studies from Creede, CO, Jerritt Canyon, NV, Coeur d'Alene district, ID and MT, southern Alaska mesothermal veins, and mid-continent MVT's

USGS Publications Warehouse

Landis, G.P.; Hofstra, A.H.

1991-01-01

Recent advances in instrumentation now permit quantitative analysis of gas species from individual fluid inclusions. Fluid inclusion gas data can be applied to minerals exploration empirically to establish chemical (gas composition) signatures of the ore fluids, and conceptually through the development of genetic models of ore formation from a framework of integrated geologic, geochemical, and isotopic investigations. Case studies of fluid inclusion gas chemistry from ore deposits representing a spectrum of ore-forming processes and environments are presented to illustrate both the empirical and conceptual approaches. We consider epithermal silver-gold deposits of Creede, Colorado, Carlin-type sediment-hosted disseminated gold deposits of Jerritt Canyon, Nevada, metamorphic silver-base-metal veins of the Coeur d'Alene district, Idaho and Montana, gold-quartz veins in accreted terranes of southern Alaska, and the mid-continent base-metal sulfide deposits of Mississippi Valley-Type (MVT's). Variations in gas chemistry determine the redox state of the ore fluids, provide compositional input for gas geothermometers, characterize ore fluid chemistry (e.g., CH4CO2, H2SSO2, CO2/H2S, organic-rich fluids, gas-rich and gas-poor fluids), identify magmatic, meteoric, metamorphic, shallow and deep basin fluids in ore systems, locate upwelling plumes of magmatic-derived volatiles, zones of boiling and volatile separation, interfaces between contrasting fluids, and important zones of fluid mixing. Present techniques are immediately applicable to exploration programsas empirical studies that monitor fluid inclusion gas threshold concentration levels, presence or absence of certain gases, or changes in gas ratios. We suggest that the greater contribution of fluid inclusion gas analysis is in the integrated and comprehensive chemical dimension that gas data impart to genetic models, and in the exploration concepts based on processes and environments of ore formation derived from these genetic models. ?? 1991.

Discrimination of iron ore deposits of granulite terrain of Southern Peninsular India using ASTER data

NASA Astrophysics Data System (ADS)

Rajendran, Sankaran; Thirunavukkarasu, A.; Balamurugan, G.; Shankar, K.

2011-04-01

This work describes a new image processing technique for discriminating iron ores (magnetite quartzite deposits) and associated lithology in high-grade granulite region of Salem, Southern Peninsular India using visible, near-infrared and short wave infrared reflectance data of Advanced Spaceborne Thermal Emission and Reflection Radiometer (ASTER). Image spectra show that the magnetite quartzite and associated lithology of garnetiferrous pyroxene granulite, hornblende biotite gneiss, amphibolite, dunite, and pegmatite have absorption features around spectral bands 1, 3, 5, and 7. ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in RGB are constructed by summing the bands representing the shoulders of absorption features as a numerator, and the band located nearest the absorption feature as a denominator to map iron ores and band ratios ((2 + 4)/3, (5 + 7)/6, (7 + 9)/8) in RGB for associated lithology. The results show that ASTER band ratios ((1 + 3)/2, (3 + 5)/4, (5 + 7)/6) in a Red-Green-Blue (RGB) color combination identifies the iron ores much better than previously published ASTER band ratios analysis. A Principal Component Analysis (PCA) is applied to reduce redundant information in highly correlated bands. PCA (3, 2, and 1 for iron ores and 5, 4, 2 for granulite rock) in RGB enabled the discrimination between the iron ores and garnetiferrous pyroxene granulite rock. Thus, this image processing technique is very much suitable for discriminating the different types of rocks of granulite region. As outcome of the present work, the geology map of Salem region is provided based on the interpretation of ASTER image results and field verification work. It is recommended that the proposed methods have great potential for mapping of iron ores and associated lithology of granulite region with similar rock units of granulite regions of Southern Peninsular India. This work also demonstrates the ability of ASTER's to provide information on iron ores, which is valuable for mineral prospecting and exploration activities.

Fluid inclusion characteristics and geological significance of the Dajinshan W-Sn polymetallic deposit in Yunfu, Guangdong Province

NASA Astrophysics Data System (ADS)

Yu, Zhangfa; Chen, Maohong; Zhao, Haijie

2015-05-01

The Dajinshan tungsten-tin polymetallic deposit is a quartz-vein-type ore deposit located in Western Guangdong Province. The ore bodies show a fairly simple shape and mainly occur as tungsten-tin polymetallic-bearing sulfide quartz veins, including quartz vein, quartz-greisens, and sulfide quartz veins, and their distribution is spatially related to Dajinshan granitoids. The formation of the deposit experienced three stages: a wolframite-molybdenite-quartz stage, a wolframite-cassiterite-sulfide-quartz stage, and a fluorite-calcite-carbonate stage. Based on detailed petrographic observations, we conducted microthermometric and Raman microspectroscopic studies of fluid inclusions formed at different ore-forming stages in the Dajinshan tungsten-tin polymetallic deposit, identifying four dominant types of fluid inclusions: aqueous two-phase inclusions, CO2-bearing inclusions, solid or daughter mineral-bearing inclusions, and gas-rich inclusions. The gas compositions of ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit are mostly CO2, CH4, and H2O. The hydrogen, oxygen, and sulfur isotopic data imply that the ore-forming fluids in the Dajinshan tungsten-tin polymetallic deposit were mainly derived from magmatic fluids, mixed with meteoric water in the ore-formation process. These results indicate that the fluid mixing and boiling led to the decomposition of the metal complex in ore-forming fluids and ore deposition.

Extraction of reduced alteration information based on Aster data: a case study of the Bashibulake uranium ore district

NASA Astrophysics Data System (ADS)

Ye, Fa-wang; Liu, De-chang

2008-12-01

Practices of sandstone-type uranium exploration in recent years in China indicate that the uranium mineralization alteration information is of great importance for selecting a new uranium target or prospecting in outer area of the known uranium ore district. Taking a case study of BASHIBULAKE uranium ore district, this paper mainly presents the technical minds and methods of extracting the reduced alteration information by oil and gas in BASHIBULAKE ore district using ASTER data. First, the regional geological setting and study status in BASHIBULAKE uranium ore district are introduced in brief. Then, the spectral characteristics of altered sandstone and un-altered sandstone in BASHIBULAKE ore district are analyzed deeply. Based on the spectral analysis, two technical minds to extract the remote sensing reduced alteration information are proposed, and the un-mixing method is introduced to process ASTER data to extract the reduced alteration information in BASHIBULAKE ore district. From the enhanced images, three remote sensing anomaly zones are discovered, and their geological and prospecting significances are further made sure by taking the advantages of multi-bands in SWIR of ASTER data. Finally, the distribution and intensity of the reduced alteration information in Cretaceous system and its relationship with the genesis of uranium deposit are discussed, the specific suggestions for uranium prospecting orientation in outer of BASHIBULAKE ore district are also proposed.

Culturable microorganisms associated with Sishen iron ore and their potential roles in biobeneficiation.

PubMed

Adeleke, Rasheed; Cloete, T E; Khasa, D P

2012-03-01

With one of the largest iron ore deposits in the world, South Africa is recognised to be among the top ten biggest exporters of iron ore. Increasing demand and consumption of this mineral triggered search for processing technologies, which can be utilised to "purify" the low-grade iron ore minerals that contain high levels of unwanted potassium (K) and phosphorus (P). This study investigated a potential biological method that can be further developed for the full biobeneficiation of low-grade iron ore minerals. Twenty-three bacterial strains that belong to Proteobacteria, Firmicutes, Bacteroidetes and Actinobateria were isolated from the iron ore minerals and identified with sequence homology and phylogenetic methods. The abilities of these isolates to lower the pH of the growth medium and solubilisation of tricalcium phosphate were used to screen them as potential mineral solubilisers. Eight isolates were successfully screened with this method and utilised in shake flask experiments using iron ore minerals as sources of K and P. The shake flask experiments revealed that all eight isolates have potentials to produce organic acids that aided the solubilisation of the iron ore minerals. In addition, all eight isolates produced high concentrations of gluconic acid followed by relatively lower concentrations of acetic, citric and propanoic acid. Scanning electron microscopy (SEM) and Fourier transform infrared (FTIR) analyses also indicated extracellular polymeric substances could play a role in mineral solubilisation.

Sodium cyanide hazards to fish and other wildlife from gold mining operations

USGS Publications Warehouse

Eisler, R.; Clark, D.R.; Wiemeyer, Stanley N.; Henny, C.J.; Azcue, Jose M.

1999-01-01

Highly toxic sodium cyanide (NaCN) is used increasingly by the international mining community to extract gold and other precious metals through milling of high grade ores and heap leaching of low grade ores. Of the 98 million kg cyanide (CN) consumed in North America in 1989, about 80% was used in gold mining (Knudson 1990). In Canada, more than 90% of the mined gold is extracted from ores with the cyanidation process. This process consists of leaching gold from the ore as a gold-cyanide complex, and gold being recovered by precipitation (Simovic and Snodgrass 1985). Milling and heap leaching require cycling of millions of liters of alkaline water containing high concentrations of potentially toxic NaCN, free cyanide, and metal cyanide complexes that are frequently accessible to wildlife. Some milling operations result in tailings ponds of 150 ha and larger. Heap leach operations that spray or drip cyanide solution onto the flattened top of the ore heap require solution processing ponds of about 1 ha in surface area. Although not intentional or desired, puddles of various sizes may occur on the top of heaps where the highest concentrations of NaCN are found. Exposed solution recovery channels are usually constructed at the base of leach heaps. All of these cyanidecontaining water bodies are hazardous to wildlife if not properly managed (Henny et al. 1994). In this account we emphasize hazards of cyanide from mining operations to fish and wildlife species and proposed mitigation to protect them.

A mineralogical perspective on the recovery of platinum group elements from Merensky Reef and UG2 at the Two Rivers mine on the Eastern limb of the Bushveld Complex in South Africa

NASA Astrophysics Data System (ADS)

Rose, Derek H.; Viljoen, K. S.; Mulaba-Bafubiandi, Antoine

2018-06-01

Published studies dealing with the process mineralogy of Pt mines on the Bushveld Complex is generally limited to the Western Bushveld. The recognition by mine management that another resource, in addition to the Upper Group 2 (UG2) reef currently being mined at the Two Rivers platinum mine (TRP), is urgently required in order to extend the life of mine, presented an opportunity to conduct such a study on the Eastern Limb of the Bushveld Complex. A process mineralogical investigation was undertaken on ore from the Merensky Reef (MR) and the UG2 at TRP. This was conducted on a suite of geological samples (channel samples) collected from the underground workings, as well as metallurgical samples obtained from the rougher circuits at the concentrator plant during the processing of MR and UG2 ore. The geological and metallurgical samples were analysed for bulk composition and quantitative mineralogy, while the geological samples were also subjected to laboratory-scale milling and flotation tests. This study shows that, although mineralogically distinct, the MR and UG2 behave similarly in terms of metallurgical performance. This holds promise for the proposed blending of MR and UG2 ores at TRP. An evaluation of the bulk rock (ore) Pt/Pd ratio as a possible indicator of the level of hydrothermal alteration of the ore, demonstrates that this may be of use in predicting recovery plant performance.

[Spectral characteristics and implications of quartz from Heliao lead-zinc polymetallic ore district in the south of Qinzhou-Hangzhou joint belt].

PubMed

Lü, Wen-Chao; Yang, Zhi-Jun; Zhou, Yong-Zhang; Li, Hong-Zhong; Zeng, Xiang-Qing; Chen, Qing; Liang, Jin; Zeng, Chang-Yu

2013-05-01

The XRD, FTIR and Raman spectrum were employed to study the characters of quartz from three types of rock samples, which are mineralized rock sample, near ore body rock sample and far away from ore body rock sample in Heliao lead-zinc polymetallic ore district. The research shows that the quartz in the mineralized rock and far away from ore body rock is pure, while the quartz in near ore body rock contains a small amount of impurities. But such small amounts of impurities did not cause apparent change in the quartz lattice parameters. From far away from ore body rock-->near ore body rock-->mineralized rock, the crystallinity and order degree of quartz are higher and higher. And the quartz in the mineralized rock has a trend to change into low symmetry quartz. It's a unique to mineralized rock that the quartz's absorption peak at 1 050 cm(-1) was split into two strongest ones. It can be used as the signs of whether exists mineralization. The cause for the quartz microstructure changes may be related to the activities of late mineralized hydrothermal fluids. Late hydrothermal influence was very weak to the quartz far away from ore body rock. And through the impact of the multi-stage hydrothermal effect, the quartz in mineralized rock may be purified by recrystallization and structural adjustment. However the quartz in near ore body rock didn't have enough hydrothermal influence, so it's not pure. Genealogy research technology is a useful technique for in-depth exploration of study area mineralization process and metallogenic regularity.

Integrate metalogenic database with GIS geological project (deposite Au-Ag Far East Russia). WEB-GIS approach.

NASA Astrophysics Data System (ADS)

Kucharenko, Evgeniy; Asavin, Alex

2015-04-01

Resource depletion has forced us to search for new ore deposit and reanalyze old mineral deposits. This is the main aim of metallogenic studies. Synthesis information about features resources work out deposit and emerging fields will play a key role in future. Development of metallogeny databases is one of the most difficult tasks for Earth sciences. Database needs to enter a large number of parameters describing the object of study - mine or ore occurrence. Majority of these parameters belong to different areas of geological knowledge. It can be ore mineralogy, geochemistry, lithology of host rocks, tectonic characteristics ore-controlling structures, geochemical parameters of ore processes, geochronological data on age of geological formations and processes of ore formation and some others. However, the cartographic materials of various scales apart from diverse documentation and numerical information are of a great importance. The adopted framework for the analysis of large-scale metallogeny has several levels: 1. The ore body (usually 1: 50000, 1: 100000) 2. The ore field, the field (1: 200000) 3. The ore cluster (1: 500000) Researchers can vary scheme and scale values, but fundamentally three levels of scale describing the location and geological structures controlling the placement of ore are included at least. Attention should be pay to the system of description the ore deposit. It is necessary to create the universal scheme for development of metallogeny information systems and set up the universal algorithm of ore deposit description. There is its own order of importance of used features and a form of description for each type of deposits and ore and genetic group and ore element. Lack of definition in the classification of a particular metallogenic object makes the choice of algorithm description justified quite weakly. It is quite notable that available features which used for description of different deposit (even of the same genetic group) are not of the same type or detailed enough. Waste deposit usually takes as a reference object with the most complete description in opposite to the recently discovered deposit not enough studied and with quite limited list of information indicators. There are following most actual tasks for information metallogeny system: 1. Search summarizing the characteristics of different objects 2. Select the most informative group of features 3. Show the links of groups of signs and analyze it as far as genesis of deposits. The actual task's list could be continued but it is enough to start. Essentially mentioned problems put us in a situation when deposit's metallogenic database is not available. There is only limited number of typical databases (for certain types of minerals) characterized nothing more than name of the fields and basic indicators of its economic importance (stocks, component content, ore types). The additional information: the age of host rock or ores or geochemistry features of some geological objects uses quite rarely. There is no systematic data for all objects in the database. Database of carbonatite deposits is the most well-developed. It should be also mentioned some works [Woolley & Kjarsgaard 2009; Bagdasarov et al.,2001; Burmistrov et al., 2008]. Unfortunately, such important characteristics as geological maps are not included there as

A summary of laboratory testing performed to characterize and select an elastomeric O-ring material to be used in the redesigned solid rocket motors of the space transportation system

NASA Technical Reports Server (NTRS)

Turner, J. E.

1993-01-01

An elastomeric O-ring material is used in the joints of the redesigned solid motors (RSRM's) of the National Space Transportation System (NSTS). The selection of the O-ring material used in the RSRM's was a very thorough process that included efforts by NASA's Marshall Space Flight Center and the Langley Research Center, and the Thiokol Corporation. One of the efforts performed at MSFC was an extensive in-house laboratory test regime to screen potential O-ring materials and ultimately to characterize the elastomeric material that was chosen to be used in the RSRM's. The laboratory tests performed at MSFC are summarized.

Development of a Chemical Process for Production of Cesium Chloride from a Canadian Pollucite Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

Parsons, H. W.; Vezina, J. A.; Simard, R.

1963-01-01

A chemical process was developed for the production of a high-purity cesium chioride from a pollucite (cesium aluminum silicate) ore from the Manitoba deposit of Chemalloy Minerais Ltd. The history of the deposit, and the present and possible future uses of cesium are briefly reviewed. Laboratory and piiot plant investigations on this ore have shown that a cyclic sulphuric acid leach followed by fractional crystallization will produce a rubidiumfree cesium alum, which can be converted to cesium chloride by thermal decomposition and ion exchange. On the basis of these findings it is concluded that the process is applicable to themore » tonnage production of cesium chloride. Reagent consumption was found to be 3.3 sulphuric acid and 0.3 lb hydrochloric acid per pound of cesium extracted. Overall extraction of cesium was 95 to 96%. (auth)« less

Manganese biomining: A review.

PubMed

Das, A P; Sukla, L B; Pradhan, N; Nayak, S

2011-08-01

Biomining comprises of processing and extraction of metal from their ores and concentrates using microbial techniques. Currently this is used by the mining industry to extract copper, uranium and gold from low grade ores but not for low grade manganese ore in industrial scale. The study of microbial genomes, metabolites and regulatory pathways provide novel insights to the metabolism of bioleaching microorganisms and their synergistic action during bioleaching operations. This will promote understanding of the universal regulatory responses that the biomining microbial community uses to adapt to their changing environment leading to high metal recovery. Possibility exists of findings ways to imitate the entire process during industrial manganese biomining endeavor. This paper reviews the current status of manganese biomining research operations around the world, identifies factors that drive the selection of biomining as a processing technology, describes challenges in exploiting these innovations, and concludes with a discussion of Mn biomining's future. Copyright © 2011 Elsevier Ltd. All rights reserved.

Loparite, a rare-earth ore (Ce, Na, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3

USGS Publications Warehouse

Hedrick, James B.; Sinha, Shyama P.; Kosynkin, Valery D.

1997-01-01

The mineral loparite (Ce, NA, Sr, Ca)(Ti, Nb, Ta, Fe+3)O3 is the principal ore of the light-group rare-earth elements (LREE) in Russia. The complex oxide has a perovskite (ABO3) structure with coupled substitutions, polymorphism, defect chemistry and a tendency to become metamict. The A site generally contains weakly bonded, easily exchanged cations of the LREE, Na and Ca. The B site generally contains smaller, highly charged cations of Ti, Nb or Fe+3. Mine production is from Russia's Kola Peninsula. Ore is beneficiated to produce a 95% loparite concentrate containing 30% rare-earth oxides. Loparite concentrate is refined by either a chlorination process or acid decomposition process to recover rare-earths, titanium, niobium and tantalum. Rare-earths are separated by solvent extraction and selective precipitation/dissolution. The concentrate is processed at plants in Russia, Estonia and Kazakstan.

Electrostatic beneficiation of ores on the moon surface

NASA Technical Reports Server (NTRS)

Inculet, I. I.; Criswell, D. R.

1979-01-01

The feasibility of the electrostatic beneficiation of lunar ores is studied. It is shown that the lunar environment with its sustained high vacuum, low temperature, and low acceleration of gravity, is suitable for the use of the electrostatic technique with magnetic as well as nonmagnetic ores. Only an initial coarse screening will be required prior to processing, as the lunar soil is already in fine particulate form. The low temperature and the absence of water suggest the use of tribo-electrification for the electric charging of lunar soils.

Biogenic catalysis in sulphide minerals' weathering processes and acid mine drainage genesis.

PubMed

Kušnierová, Mária; Praščáková, Mária; Nowak, Anna K; Gorazda, Katarzyna; Wzorek, Zbigniew

2014-01-01

Bioleaching and biogenesis are the main outputs from a large group of environmental processes participating in the natural material cycle, used in raw materials processing. Bio-oxidation reactions are the main basis for bioleaching procedures, often participating in parallel leaching processes. During the leaching processes of polycomponent sulphide substrates, the factor of process selection also plays an important role, being in direct relation to the electric properties and galvanic effect occurring between the individual components of the leaching substrate. This work gives a summary of the results of a research focused on the possibilities of using biotechnological procedures for treatment of Slovak sulphide ores. The object of the research is extraction of valuable metals, undesirable admixtures and degradation of crystal lattice of sulphides for subsequent chemical leaching processing of precious metals. The results of experiments on the existence of biogenic processes in situ on waste dumps from exploitation containing residual sulphides are also presented. The processes result in acid mine drainage water generation. These waters are strongly mineralised (over 48 g/L) and of low pH; that is why they are very caustic. The arsenic content (2.558 mg/L) in outflowing waters from old mines is high and over the limits set by the law.

Effect of temperature in the selective reduction process of limonite nickel ore

NASA Astrophysics Data System (ADS)

Mayangsari, W.; Febriana, Eni; Prasetyo, A. B.

2018-05-01

Temperature is the main factor for the reduction process that influence to reduction degree, phase and morphology transformation. In order to determine these effects which is caused by reduction temperature, this study was conducted. Limoniticnickel ore was prepared by drying and size reduction. A part of prepared limonitewas characterized with XRF to determine the chemical composition. The other part was mixed with reducing agent and CaSO4 to produce pellet. A series of selective reduction processes were conducted to the pellet by using graphite crucible in the muffle furnace carbolite at 800° - 1100°C for 60 minutes. Reduced ore characterized by using XRD and SEM analysis. Based on the result study, weight loss and reduction degree increase as temperature raised along with CaSO4 addition. Moreover, it caused decomposition and transformation to the metallic phase of kamacite and iron up to 7.51% and 41.44% respectively in the reduction process at 1100°C for 60 minutes. Furthermore, particle size growth as metallic phase content increased.

The extractive metallurgy of gold

NASA Astrophysics Data System (ADS)

Kongolo, K.; Mwema, M. D.

1998-12-01

Mössbauer spectroscopy has been successfully used in investigation of the gold compounds present in ores and the gold species which occur during the process metallurgy of this metal. This paper is a survey of the basic recovery methods and techniques used in extractive metallurgy of gold. Process fundamentals on mineral processing, ore leaching, zinc dust cementation, adsorption on activated carbon, electrowinning and refining are examined. The recovery of gold as a by-product of the copper industry is also described. Alternative processing methods are indicated in order to shed light on new interesting research topics where Mössbauer spectroscopy could be applied.

Composition and origin of Early Cambrian Tiantaishan phosphorite-Mn carbonate ores, Shaanxi Province, China

USGS Publications Warehouse

Hein, J.R.; Fan, D.; Ye, J.; Liu, T.; Yeh, H.-W.

1999-01-01

The Tiantaishan phosphorite-Mn carbonate ores occur in the Early Cambrian Tananpo Formation in complexly folded and faulted rocks located in southern Shaanxi Province. About 65 x 106 tonnes of 17% P2O5 ore reserves exist and Mn-ore reserves are about 8.3 x 106 tonnes of +18% Mn. The stratigraphic sequence in ascending order consists of black phyllite, black to gray phosphorite ore, black phyllite, rhodochrostone ore, Mn mixed-carbonates, and dolostone. Data are presented from microprobe mineral chemistry, whole-rock chemistry, stable isotopes of carbonates, X-ray mineralogy, petrographic and SEM observations, and statistical analysis of chemical data. The dominant ore-forming minerals are hydroxy- and carbonate fluorapatite and Ca rhodochrosite, with Mg kutnahorite and dolomite comprising the Mn mixed-carbonate section. Pyrite occurs in all rock types and alabandite (MnS) occurs throughout the rhodochrostone section. The mean P2O5 content of phosphorite is 31% and argillaceous phosphorite is 16%, while the mean MnO content of rhodochrostone ore is 37%. Phosphorite ores are massive, spheroidal, laminated, and banded, while rhodochrostone ores have oolitic, spheroidal, and granular fabrics. The most distinguishing characteristics of the ores are high total organic carbon (TOC) contents (mean 8.4%) in the phosphorite and high P2O5 contents (mean 2.7%) in the rhodochrostone ore. The atypically high TOC contents in the Tiantaishan phosphorite probably result from very strong productivity leading to high sedimentation rates accompanied by weak reworking of sediments; poor utilization of the organic matter by bacteria; and/or partial replacement of bacterial or algal mats by the apatite. The depositional setting of the ores was the margin of an epicontinental seaway created as a direct consequence of global processes that included break-up of a supercontinent, formation of narrow seaways, creation of extensive continental shelves, overturn of stagnant, metal-rich deep-ocean waters, and marine transgression. Water depth increased from deposition of the black phyllite sequence through deposition of the Mn mixed-carbonate sequence, then shallowed again during deposition of the overlying dolostone sequence. Bottom waters were mostly dysoxic to suboxic, but fluctuated from oxic to anoxic. Productivity was high during deposition of the black phyllite sequence, increased during precipitation of phosphorite, and then decreased to moderate levels during precipitation of rhodochrostone ores. Biosilica contributions occur in each lithology, but are greatest in rhodochrostone. Changes in sedimentation were determined by changes in water depth, productivity, upwelling, sea-level change, and ventilation of the depositional basin. The source of the phosphorus was organic matter produced in great quantities during deposition of the black phyllite and phosphorite sequences in a zone of coastal upwelling. Organic matter accumulation was rapid. Globally, Mn was supplied by overturn of stagnant, metal-rich deep-ocean waters, which were redistributed to areas of coastal upwelling and seaways; that process may have been initiated by latest Proterozoic glaciations which would have promoted density stratification and accumulation and storage of metals. Regionally, Mn was supplied by terrigenous input into the shallow seaway and hydrothermal input into the deeper water parts of that seaway. Locally, Mn sources included leaching and transport of metals from the sediment column. Manganese was stored locally in low-oxygen (not anoxic) seawater prior to Mn-ore formation. The source of the carbon in the Mn carbonates and dolostones was predominantly seawater bicarbonate and secondarily CO2 derived from the oxidation of organic matter in the bacterially mediated diagenetic zone of sulfate reduction.

Improving the engineering-and-economical performance of ore-thermal electric furnaces in the smelting of silicomanganese

NASA Astrophysics Data System (ADS)

Kondrashov, V. P.; Pogrebisskiy, M. Ya; Lykov, A. G.; Rabinovich, V. L.; Bulgakov, A. S.

2018-02-01

Ways of increase of ore-heating electric furnaces, used for production of silicomanganese, engineering-and-economical performance are analyzed. Questions of data of the electric, thermal and technological modes of the furnace functioning collecting and processing for use in operation of an advanced control system of the furnace providing increase in technical and economic efficiency of technological process and an adaptability to quality of burden stock are considered.

Scandium recovery from slags after oxidized nickel ore processing

NASA Astrophysics Data System (ADS)

Smyshlyaev, Denis; Botalov, Maxim; Bunkov, Grigory; Rychkov, Vladimir; Kirillov, Evgeny; Kirillov, Sergey; Semenishchev, Vladimir

2017-09-01

One of the possible sources of scandium production - waste (slags) from processing of oxidized nickel ores, has been considered in present research work. The hydrometallurgical method has been selected as the primary for scandium extraction. Different reagents for leaching of scandium, such as sulfuric acid, various carbonate salts and fluorides, have been tested. Sulfuric acid has been recognized as an optimal leaching reagent. Sulfuric acid concentration of 100 g L-1 allowed recovering up to 97 % of scandium.

Sources of Minor and Rare-Earth Elements in Hydrothermal Edifices of Near-Continental Rifts with Sedimentary Cover: Evidence from the Guaymas Basin, Southern Trough

NASA Astrophysics Data System (ADS)

Lein, A. Yu.; Dara, O. M.; Bogdanova, O. Yu.; Novikov, G. V.; Ulyanova, N. V.; Lisitsyn, A. P.

2018-03-01

The mineralogy and geochemistry of a fragment of an active hydrothermal edifice from the Hydrothermal Hill of the Southern Trough valley of the Guaymas Basin in the Gulf of California were studied. The sample was collected from a depth of 1995 m by the Pisces manned submersible on cruise 12 of the R/V Akademik Mstislav Keldysh, Institute of Oceanology, Russian Academy of Sciences. The fragment and the edifice itself consists of two accrete pipes: ore (pyrrhotite) and barren (carbonate) combined in a single edifice by an outer barite-opal zone. The ore edifice is located in the rift zone of the Guaymas Basin with a thick sedimentary cover and is depleted in metals in comparison with ores from rift zones of the open ocean, which are not blocked by sedimentary deposits. This is explained by loss of metals at the boundary between hot sills and sedimentary rocks and by the processes of interaction of hydrothermal solutions with sedimentary deposits. The sedimentary series faciitates long-term preservation of endogenous heat and the ore formation process. Ore edifices of the Guaymas Basin are mostly composed of pyrrhotite, have a specific set of major elements, microelements and REEs, and contain naphthenic hydrocarbons. They may be search signs of hidden polymetallic deposits, considered to be the roots of ore occurrences localized under the surface of the bottom in young active rifts with high spreading and sedimentation rates, i.e., in near-continental areas of rifts of the humid zone with avalanche sedimentation.

CATALYZED OXIDATION OF URANIUM IN CARBONATE SOLUTIONS

DOEpatents

Clifford, W.E.

1962-05-29

A process is given wherein carbonate solutions are employed to leach uranium from ores and the like containing lower valent uranium species by utilizing catalytic amounts of copper in the presence of ammonia therein and simultaneously supplying an oxidizing agent thereto. The catalysis accelerates rate of dissolution and increases recovery of uranium from the ore. (AEC)

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2013 CFR

2013-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.34 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

... underground, that produce uranium ore, excluding mines using in situ leach methods, shall not exceed: Effluent... leach process for the extraction of uranium or from mines and mills using in situ leach methods. The... Vanadium Ores Subcategory § 440.34 New source performance standards (NSPS). Except as provided in subpart L...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2014 CFR

2014-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... provided in subpart L of this part any new source subject to this subsection must achieve the following... demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that...

40 CFR 440.104 - New source performance standards (NSPS).

Code of Federal Regulations, 2012 CFR

2012-07-01

..., in-situ leach or vat-leach processes to extract copper from ores or ore waste materials. The Agency... provided in subpart L of this part any new source subject to this subsection must achieve the following... demonstrated technology (BADT): (a) The concentration of pollutants discharged in mine drainage from mines that...

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

NASA Astrophysics Data System (ADS)

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U(IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

PubMed Central

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-01-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U(IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment. PMID:28569759

Biogenic non-crystalline U (IV) revealed as major component in uranium ore deposits

DOE PAGES

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.; ...

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV) generated through biologically mediated U (VI) reduction is the predominant U (IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotopemore » signatures, consistent with largely biotic reduction of U (VI) to U (IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.« less

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits.

PubMed

Bhattacharyya, Amrita; Campbell, Kate M; Kelly, Shelly D; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-06-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI) ) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV)  generated through biologically mediated U (VI)  reduction is the predominant U (IV)  species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238 U-enriched isotope signatures, consistent with largely biotic reduction of U (VI) to U (IV) . This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

Biogenic non-crystalline U (IV) revealed as major component in uranium ore deposits

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly D.

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U (VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U (IV) generated through biologically mediated U (VI) reduction is the predominant U (IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (~58-89%) of U is bound as U (IV) to C-containing organic functional groups or inorganic carbonate, while uraninite and U (VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotopemore » signatures, consistent with largely biotic reduction of U (VI) to U (IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U (IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.« less

Biogenic non-crystalline U(IV) revealed as major component in uranium ore deposits

USGS Publications Warehouse

Bhattacharyya, Amrita; Campbell, Kate M.; Kelly, Shelly; Roebbert, Yvonne; Weyer, Stefan; Bernier-Latmani, Rizlan; Borch, Thomas

2017-01-01

Historically, it is believed that crystalline uraninite, produced via the abiotic reduction of hexavalent uranium (U(VI)) is the dominant reduced U species formed in low-temperature uranium roll-front ore deposits. Here we show that non-crystalline U(IV) generated through biologically mediated U(VI) reduction is the predominant U(IV) species in an undisturbed U roll-front ore deposit in Wyoming, USA. Characterization of U species revealed that the majority (∼58-89%) of U is bound as U(IV)to C-containing organic functional groups or inorganic carbonate, while uraninite and U(VI) represent only minor components. The uranium deposit exhibited mostly 238U-enriched isotope signatures, consistent with largely biotic reduction of U(VI) to U(IV). This finding implies that biogenic processes are more important to uranium ore genesis than previously understood. The predominance of a relatively labile form of U(IV) also provides an opportunity for a more economical and environmentally benign mining process, as well as the design of more effective post-mining restoration strategies and human health-risk assessment.

A study of bauxite tailing quality improvement by reverse flotation

NASA Astrophysics Data System (ADS)

Wulandari, W.; Purwasasmita, M.; Sanwani, E.; Malatsih, W.; Fadilla, F.

2018-01-01

The pre-treatment of bauxite ore from Tayan, West Kalimantan includes washing and screening fine bauxite particles (-2mm) prior as the feed to the Bayer process for producing alumina. These fine particles are believed to have high content of silica which is detrimental to the process. This washed bauxite tailing still has a significant amount of alumina content. Previous research has indicated that bauxite ore can be upgraded by applying reverse flotation method to reduce its silica content in the ore. Therefore, this study is aimed to utilize reverse flotation method to recover alumina content from washed bauxite tailing. The reverse flotation experiments were carried out at pH of 6 and 8; while the particle sizes were varied at - 140+270 mesh and -270 mesh, using a batch and circuit configuration. The result of this study shows that the batch reverse flotation can recover alumina in the tailing up to 81.4%, however the silica content is still significant. The complexity of silica-alumina minerals in the tailing prevents a complete separation of the ores by only using reverse flotation.

Porphyry-copper ore shells form at stable pressure-temperature fronts within dynamic fluid plumes.

PubMed

Weis, P; Driesner, T; Heinrich, C A

2012-12-21

Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

Porphyry-Copper Ore Shells Form at Stable Pressure-Temperature Fronts Within Dynamic Fluid Plumes

NASA Astrophysics Data System (ADS)

Weis, P.; Driesner, T.; Heinrich, C. A.

2012-12-01

Porphyry-type ore deposits are major resources of copper and gold, precipitated from fluids expelled by crustal magma chambers. The metals are typically concentrated in confined ore shells within vertically extensive vein networks, formed through hydraulic fracturing of rock by ascending fluids. Numerical modeling shows that dynamic permeability responses to magmatic fluid expulsion can stabilize a front of metal precipitation at the boundary between lithostatically pressured up-flow of hot magmatic fluids and hydrostatically pressured convection of cooler meteoric fluids. The balance between focused heat advection and lateral cooling controls the most important economic characteristics, including size, shape, and ore grade. This self-sustaining process may extend to epithermal gold deposits, venting at active volcanoes, and regions with the potential for geothermal energy production.

Ore genesis dating: implication of Sm-Nd method using sulfide minerals for mafic-ultramafic layered intrusions of Fennoscandian Shield

NASA Astrophysics Data System (ADS)

Serov, Pavel; Bayanova, Tamara; Steshenko, Ekaterina; Ekimova, Nadezhda

2015-04-01

The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. In to Sm-Nd measurements steadily introduce new minerals-geochronometers (i.e. titanite, burbancite, eudialite etc.). Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than those in chondrites (Rimskaya-Korsakova et. al., 2003). In (Kong et. al., 2000) sulfides from two metamorphosed chondrites were studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). For the first time in Russian geochemistry laboratories using sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated and brecciform ores of the following objects - Pilguyarvi Cu-Ni deposits, Pechenga (1965±87 Ma); impregnated (2433±83 Ma) and redeposited (1903±24 Ma) ores of Ahmavaara intrusion (Finland); Kolvitsa massif metagabbro (1990±92 Ma, which reflect the age of Sm-Nd system closure in sulfide minerals); olivine orthopyroxenites of Sopcha 'Ore bed' (2442±59 Ma); ore gabbronorites of Penikat PGE-bearing layered intrusion (2426±38 Ma (Ekimova et.al., 2011); Pt-Pd gabbro-pegmatite ores (2476± 41 Ma, which agrees well with the U-Pb zircon age - 2470±9 Ma (Bayanova, 2004) and gabbronorites (2483±86 Ma) of PGE Kievey deposit and Fedorova Tundra metagabbroids (2494±54 Ma); Monchetundra gabbronorites - 2489±49 Ma. All investigations are devoted to memory of academician RAS, professor F. Mitrofanov (Russia), he was a leader of scientific school for geology, geochemistry and metallogenesis of ore deposits. The studies were supported by the RFBR 13-05-00493, OFI-M 13-05-12055, Department of Earth Sciences RAS (programs 2 and 4), IGCP-599.

New understanding on separation of Mn and Fe from ferruginous manganese ores by the magnetic reduction roasting process

NASA Astrophysics Data System (ADS)

Liu, Bingbing; Zhang, Yuanbo; Wang, Juan; Wang, Jia; Su, Zijian; Li, Guanghui; Jiang, Tao

2018-06-01

Magnetic reduction roasting followed by magnetic separation process is reported as a simple route to realize separation of Mn and Fe from ferruginous manganese ores (Fe-Mn ores). However, the separation and recovery of Mn and Fe oxides are not very effective. This work clarified the underlying reason for the poor separation and also proposed some suggestions for the magnetic reduction process. In this work, the effect of temperature on the magnetic reduction roasting - magnetic separation of Fe-Mn ore was investigated firstly. Then the reduction behaviors of MnO2-Fe2O3 system and MnO2-Fe2O3-10 wt.%SiO2 system under 10 vol.% CO-90 vol.% CO2 at 600-1000 °C were investigated by XRD, XPS, SEM-EDS, VSM, DSC and thermodynamics analyses. Reduction and separation tests showed that higher reduction temperature was beneficial to the recovery of iron while it's not in favor of the recovery of manganese when the temperature was over 800 °C. The formation of composite oxide MnxFe3-xO4 with strong magnetism between the interface of the MnO2 and Fe2O3 particles leaded to the poor separation of iron and manganese. In addition, the formation mechanism of MnxFe3-xO4 from MnO2 and Fe2O3 as well as the interface reaction reduced under 10 vol.% CO was discussed in this study. Finally, some suggestions were recommended for the magnetic reduction roasting for utilizing the Fe-Mn ores effectively.

Reducing acid leaching of manganiferous ore: effect of the iron removal operation on solid waste disposal.

PubMed

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca; Vegliò, Francesco

2009-01-01

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary iron removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO3, NaOH, and Na2CO3. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore

PubMed Central

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-01-01

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process. PMID:27374991

Mechanism of sodium chloride in promoting reduction of high-magnesium low-nickel oxide ore.

PubMed

Zhou, Shiwei; Wei, Yonggang; Li, Bo; Wang, Hua; Ma, Baozhong; Wang, Chengyan

2016-07-04

Sodium chloride has been proved that it is an effective promoter for the reduction of high-magnesium, low-nickel oxide ore. The aim of current work is to clarify the promotion behavior of sodium chloride in the roasting reduction process. The influence of moisture on the reduction of ore in the presence of sodium chloride is studied to get clear comprehension of promotion process. In the presence of moisture, the HCl is produced by pyrohydrolysis of sodium chloride for chlorinating nickel and iron oxides, moreover, interactions between metallic oxides and sodium chloride are also a way for chlorination at high temperature (>802 °C); subsequently, the metal chloride would be reduced by reductant. In the absence of moisture, the magnetic separation results show that the recoveries of iron and nickel have a significant increase; moreover, olivine structure would be destroyed gradually with the increase of roasting temperature in the action of sodium chloride, and the sodium chloride existed in high-magnesium, low-nickel oxide ore could make the NiO isolate from NiO-bearing minerals. The NiO reacts with Fe2O3 at high temperature to form NiFe2O4, which is conductive to the formation of Ni-Fe alloy during the reduction process.

Internal structures and dating of non-sulphide Zn deposits using rock magnetism: insights from the Moroccan High Atlas

NASA Astrophysics Data System (ADS)

Charles, Nicolas; Choulet, Flavien; Sizaret, Stanislas; Chen, Yan; Barbanson, Luc; Ennaciri, Aomar; Badra, Lakhlifi; Branquet, Yannick

2016-01-01

The renewal of interest in Zn-Pb non-sulphide ores has been induced by mineral processing improvement and leads to new exploration and mining projects in the world. Although the mineralogy is often precisely known, and despite several studies linking ore deposition to regional tectonics, absolute dating of non-sulphide stages is rare and structure of ore bodies was largely disregarded. Geochronological data from non-sulphide ores are essential to timely constrain alteration episodes and to insert supergene ore genesis in the climate and tectonic evolution of the metallogenic province. The access to internal organization of ore could reveal post-mineralization episodes related to supergene evolution. Thus, a rock magnetism study combining anisotropy of magnetic susceptibility (AMS) and palaeomagnetism was performed on four non-sulphide deposits from the Moroccan High Atlas. AMS generally shows similar horizontal magnetic fabrics for ores and the clayey and carbonaceous internal sediments filling karstic cavities. The palaeomagnetic directions of ores and internal sediments are compatible, and the calculated poles are consistent with the last 30 Ma of the Africa apparent polar wander path, with an upper age at 0.78 Ma. The proposed three-step scenario is placed within the evolution of the Moroccan High Atlas belt. Deposition of primary sulphides is contemporaneous with opening of the Tethyan and Atlantic oceans. During the Tertiary, intracontinental deformation gave rise to the High Atlas fold-and-thrust belt and to regional uplift. Finally, Zn-Pb sulphides hosted in carbonates experienced oxidation under an arid climate to form karst-related Zn-Pb non-sulphide ores. These promising results pave the way for an efficient method to constrain the internal fabrics and age of Zn supergene deposits.

Restructuring the Uranium Mining Industry in Romania: Actual Situation and Prospects

DOE Office of Scientific and Technical Information (OSTI.GOV)

Georgescu, P.D.; Petrescu, S.T.; Iuhas, T.F.

2002-07-01

Uranium prospecting in Romania has started some 50 years ago, when a bilateral agreement between Romania and the former Soviet Union had been concluded and a joint Romanian-Soviet enterprise was created. The production started in 1952 by the opening of some deposits from western Transylvania (Bihor and Ciudanovita). From 1962 the production has continued only with Romanian participation on the ore deposit Avram Iancu and from 1985 on the deposits from Eastern Carpathians (Crucea and Botusana). Starting with 1978 the extracted ores have been completely processed in the Uranium Ore Processing Plant from Feldioara, Brasov. Complying with the initial stipulationsmore » of the Nuclear National Program launched at the beginning of the 1980's, the construction of a nuclear power station in Cernavoda has started in Romania, using natural uranium and heavy water (CANDU type), having five units of 650 MW installed capacity. After 1989 this initial Nuclear National Program was revised and the construction of the first unit (number 1) was finalized and put in operation in 1996. In 2001 the works at the unit number 2 were resumed, having the year 2005 as the scheduled activating date. The future of the other 3 units, being in different construction phases, hasn't been clearly decided. Taking into consideration the exhaustion degree of some ore deposits and from the prospect of exploiting other ore deposits, the uranium industry will be subject of an ample restructuring process. This process includes workings of modernization of the mines in operation and of the processing plant, increasing the profitableness, lowering of the production costs by closing out and ecological rehabilitation of some areas affected by mining works and even new openings of some uraniferous exploitations. This paper presents the actual situation and the prospects of uranium mining industry on the base of some new technical and economical strategic concepts in accordance with the actual Romanian Program for Nuclear Energetics. (authors)« less

Application of Odor Sensors to Ore Sorting and Mill Feed Control

DOE Office of Scientific and Technical Information (OSTI.GOV)

Michael G. Nelson

2005-08-01

Control of the feed provided to mineral processing facilities is a continuing challenge. Much effort is currently being devoted to overcoming these problems. These projects are usually described under the general headings of Mine-to-Mill Integration or Mine-Mill Optimization. It should be possible to combine the knowledge of ore type, mineralogy, and other characteristics (located in the mine modeling system), with the advanced capabilities of state-of-the-art mill control systems, to achieve an improved level of control in mineral processing that will allow optimization of the mill processes on an almost real-time basis. This is not happening because mill feed it ismore » often treated as a uniform material, when in reality it varies in composition and characteristics. An investigation was conducted to assess the suitability of odor sensors for maintaining traceability in ore production and processing. Commercially available sensors are now used in food processing, environmental monitoring, and other applications and can detect the presence of very small amounts (0.1-500 ppm) of some molecules. An assortment of such molecules could be used to ''tag'' blocks of ore as they are mined, according to their respective characteristics. Then, as the ore came into the mill, an array of ''electronic noses'' could be used to assess its characteristics in real time. It was found that the Cyranose 320{trademark}, a commercially available odor sensor, can easily distinguish among samples of rock marked with almond, cinnamon, citronella, lemon, and orange oils. Further, the sensor could detect mixtures of rocks marked with various combinations of these oils. Treatment of mixtures of galena and silica with odorant compounds showed no detrimental effects on flotation response in laboratory tests. Additional work is recommended to determine how this concept can be extended to the marking of large volumes of materials.« less

Copper Deposits in Sedimentary and Volcanogenic Rocks

USGS Publications Warehouse

Tourtelot, Elizabeth B.; Vine, James David

1976-01-01

Copper deposits occur in sedimentary and volcanogenic rocks within a wide variety of geologic environments where there may be little or no evidence of hydrothermal alteration. Some deposits may be hypogene and have a deep-seated source for the ore fluids, but because of rapid cooling and dilution during syngenetic deposition on the ocean floor, the resulting deposits are not associated with hydrothermal alteration. Many of these deposits are formed at or near major tectonic features on the Earth's crust, including plate boundaries, rift valleys, and island arcs. The resulting ore bodies may be stratabound and either massive or disseminated. Other deposits form in rocks deposited in shallow-marine, deltaic, and nonmarine environments by the movement and reaction of interstratal brines whose metal content is derived from buried sedimentary and volcanic rocks. Some of the world's largest copper deposits were probably formed in this manner. This process we regard as diagenetic, but some would regard it as syngenetic, if the ore metals are derived from disseminated metal in the host-rock sequence, and others would regard the process as epigenetic, if there is demonstrable evidence of ore cutting across bedding. Because the oxidation associated with diagenetic red beds releases copper to ground-water solutions, red rocks and copper deposits are commonly associated. However, the ultimate size, shape, and mineral zoning of a deposit result from local conditions at the site of deposition - a logjam in fluvial channel sandstone may result in an irregular tabular body of limited size; a petroleum-water interface in an oil pool may result in a copper deposit limited by the size and shape of the petroleum reservoir; a persistent thin bed of black shale may result in a copper deposit the size and shape of that single bed. The process of supergene enrichment has been largely overlooked in descriptions of copper deposits in sedimentary rocks. However, supergene processes may be involved during erosion of any primary ore body and its ultimate displacement and redeposition as a secondary deposit. Bleached sandstone at the surface may indicate significant ore deposits near the water table.

New data on the substantial composition of Kalba rare metal deposits

NASA Astrophysics Data System (ADS)

Oitseva, T. A.; Dyachkov, B. A.; Vladimirov, A. G.; Kuzmina, O. N.; Ageeva, O. V.

2017-12-01

Geotectonic position, features of the geological structure and rare metal specialization of the Kalba-Narym granitoid belt formed in the Hercynian cycle in the postcollision (orogenic) geodynamic situation are considered. A geological-genetic model for the formation of the leading type of rare-metal pegmatite deposits (Ta, Nb, Be, Li, etc.) is presented. They are spatially and genetically related mainly to the granitoids of the 1st phase of the Kalba complex, P1 (Bakennoye, Jubilee, Belaya Gora, etc.). The rhythmically pulsating orientation of the process of pegmatite formation with the introduction of ore-bearing fluids (H2O, F, B, Cl, Ta, Nb, Be, etc.) is emphasized from the intracamera focus of a semi-closed magmatic system. The preferred location of ore pegmatite veins in granitoids of moderate basicity occupying an intermediate position in the petrochemical composition between normal granites and granodiorites geochemically specialized in Li, Rb, Cs, Sn, Nb, Ta. The leading ore-controlling role of the latitudinal deep faults of the ancient site in the distribution of rare-metal ore fields and deposits (Ognevsk-Bakennoye, Asubulak, Belogorsk, etc.) is determined. There is a zonal structure of pegmatite veins, a gradual development of mineral complexes from the graphic and oligoclase-microcline (non-ore) to microcline-albite and color albite-spodumene (ore). The mineralization of pegmatite veins is determined by the degree of intensity of the manifestation in them of metasomatic processes (microclinization, alibitization, greisenization, spodumenization, tourmalinization, etc.) and the identification of the main ore minerals (tantalite-columbite, cassiterite, spodumene and beryl). The diversity of the material composition of rare-metal pegmatites containing many unique minerals (cleavelandite, lepidolite, ambligonite, color tourmaline, spodumene, pollucite, etc.) is reflected, which brings them closer to the pegmatite deposits of foreign countries (Koktogai, Bernik Lake, etc.). New results of the investigation of the material composition of ore-bearing granites, pegmatites and typomorphic minerals using electron microscopy reflecting the distribution of rare-earth, rare-metal, chalcophile and other elements in them are presented. Indicators of rare metal ore formation are rock-forming minerals of granites (quartz, microcline, biotite, muscovite), ore and associated minerals (cleavelandite, lepidolite, cassiterite, etc.). The most informative minerals include mica (muscovite, giltbertite, lepidolite), colored tourmalines and beryls of different composition and color. Identified typomorphic minerals and geochemical elements-indicators of rare metal pegmatite formation are considered as a leading search criterion in assessing the prospects of the territory of East Kazakhstan.

Physicochemical characteristics of aerosol particles generated during the milling of beryllium silicate ores: implications for risk assessment.

PubMed

Stefaniak, Aleksandr B; Chipera, Steve J; Day, Gregory A; Sabey, Phil; Dickerson, Robert M; Sbarra, Deborah C; Duling, Mathew G; Lawrence, Robert B; Stanton, Marcia L; Scripsick, Ronald C

2008-01-01

Inhalation of beryllium dusts generated during milling of ores and cutting of beryl-containing gemstones is associated with development of beryllium sensitization and low prevalence of chronic beryllium disease (CBD). Inhalation of beryllium aerosols generated during primary beryllium production and machining of the metal, alloys, and ceramics are associated with sensitization and high rates of CBD, despite similar airborne beryllium mass concentrations among these industries. Understanding the physicochemical properties of exposure aerosols may help to understand the differential immunopathologic mechanisms of sensitization and CBD and lead to more biologically relevant exposure standards. Properties of aerosols generated during the industrial milling of bertrandite and beryl ores were evaluated. Airborne beryllium mass concentrations among work areas ranged from 0.001 microg/m(3) (beryl ore grinding) to 2.1 microg/m(3) (beryl ore crushing). Respirable mass fractions of airborne beryllium-containing particles were < 20% in low-energy input operation areas (ore crushing, hydroxide product drumming) and > 80% in high-energy input areas (beryl melting, beryl grinding). Particle specific surface area decreased with processing from feedstock ores to drumming final product beryllium hydroxide. Among work areas, beryllium was identified in three crystalline forms: beryl, poorly crystalline beryllium oxide, and beryllium hydroxide. In comparison to aerosols generated by high-CBD risk primary production processes, aerosol particles encountered during milling had similar mass concentrations, generally lower number concentrations and surface area, and contained no identifiable highly crystalline beryllium oxide. One possible explanation for the apparent low prevalence of CBD among workers exposed to beryllium mineral dusts may be that characteristics of the exposure material do not contribute to the development of lung burdens sufficient for progression from sensitization to CBD. In comparison to high-CBD risk exposures where the chemical nature of aerosol particles may confer higher bioavailability, respirable ore dusts likely confer considerably less. While finished product beryllium hydroxide particles may confer bioavailability similar to that of high-CBD risk aerosols, physical exposure factors (i.e., large particle sizes) may limit development of alveolar lung burdens.

Technological pretreatment of the synchysite non-oxidized ore

NASA Astrophysics Data System (ADS)

Munkhtsetseg, B.; Burmaa, G.

2013-06-01

Mongolia has rich deposits of rare, precious, and poly-metallic ores. Nowadays, it is important to research separation of rare earth elements oxides concentrates from the ores, analyze their unique physical chemical characteristics, and purified it. Our investigation on raw materials focuses on rare earth non-oxidized ores. Main mineral in this rock sample is Synchysite (LnCa(CO3)2F. We did technological and thermal pretreatment: direct sulphurization (H2SO4), sulphurization with subsequent roasting (800°C+H2SO4), sulphurization prior to roasting (H2SO4+650°C). Sulphurization method based on dissolution of rare earth mineral into sulfuric acid (93%) according to the reaction. The amount of rare earth element oxides is almost 10 times greater (29.16%) after direct sulphurization process, almost 8 times greater (21.14%) after sulphurization with subsequent roasting, and almost 20 times greater (44.62%) after sulphurization prior to roasting process. After those technological pretreatment raw material's micro elements Thorium and Uranium contents are reduced as follows: H2SO4>800°C+H2SO4>H2SO4+650°C. These results show that cerium group rare earth elements have very good solubility in water at +2°C temperature and decreasing micro elements content uranium and thorium good pretreatment condition is prior to roasting (H2SO4+650°C) of synchysite non-oxidized ore.

Ore-forming fluid system of bauxite in WZD area of northern Guizhou province, China

NASA Astrophysics Data System (ADS)

Cui, Tao

2017-12-01

The ore-forming fluid system of bauxite in Wuchuan-Zheng,an-Daozhen (short for WZD) Area of northern Guizhou Province was studied from the perspective of deposit formation mechanism. It was discovered that ore-forming fluids were mainly effective for transporting and leaching during the formation of bauxite. The means of transport mainly included colloidal transport, suspended transport and gravity flow transport. In the course of their leaching, fluids had a range of chemical reactions, as a result of which elements such as silicon and iron migrated downwards. In this process, properties of fluids changed as well.

The role of magmas in the formation of hydrothermal ore deposits

USGS Publications Warehouse

Hedenquist, Jeffrey W.; Lowenstern, Jacob B.

1994-01-01

Magmatic fluids, both vapour and hypersaline liquid, are a primary source of many components in hydrothermal ore deposits formed in volcanic arcs. These components, including metals and their ligands, become concentrated in magmas in various ways from various sources, including subducted oceanic crust. Leaching of rocks also contributes components to the hydrothermal fluid—a process enhanced where acid magmatic vapours are absorbed by deeply circulating meteoric waters. Advances in understanding the hydrothermal systems that formed these ore deposits have come from the study of their active equivalents, represented at the surface by hot springs and volcanic fumaroles.

Sulfide minerals as new Sm-Nd geochronometers for ore genesis dating of mafic-ultramafic layered intrusions

NASA Astrophysics Data System (ADS)

Serov, Pavel; Ekimova, Nadezhda; Bayanova, Tamara

2014-05-01

The main method of dating the ore process was the Re-Os method of sulfides (Luck, Allegre, 1983; Walker et. al., 1991). However, studies of Re-Os systematics of sulfide minerals do not always give the correct ages and showing the disturbances of the Re-Os systematics. At the same time, Sm-Nd age of sulfides in good agreement with the U-Pb dating on zircon and baddeleyite and suggests that the Sm-Nd system of sulfides is more resistant to secondary alteration processes. Our studies have shown that along with rock-forming, ore minerals (sulfides) can be used to determine the ore genesis time of industrially important geological sites, since exactly with the sulfides the industry Pt-Pd mineralization is closely connected. The Sm-Nd investigations steadily employ new minerals-geochronometers. Of these, sulfides of PGE-bearing layered intrusions are quite important in terms of dating the process of ore origin. Studying the REE distribution in the sulfides of MOR hydrothermal sources has shown possible REE presence in the sulfide lattice (Rimskaya-Korsakova et. al., 2003). These are difficult to carry out because the concentrations of Sm and Nd isotopes in sulfides are much lower than chondrites (Rimskaya-Korsakova et. al., 2003). For the first time in Russia with sulfide and rock-forming minerals and WR in Sm-Nd method have been dated impregnated and brecciform ores of the following objects: Pilguyarvi Cu-Ni deposits, Pechenga (1965±87 Ma); impregnated (2433±83 Ma) and redeposited (1903±24 Ma) ores of Ahmavaara intrusion (Finland); ore gabbronorites of Penikat PGE-bearing layered intrusion (2426±38 Ma (Ekimova et.al., 2011); Pt-Pd gabbro-pegmatite ores (2476± 41 Ma, which agrees with the U-Pb zircon age - 2470±9 Ma (Bayanova, 2004) and gabbronorites (2483±86 Ma) of PGE Kievei deposit and Fedorova Tundra metagabbroids (2494±54 Ma); Monchetundra gabbronorites - 2489±49 Ma. In (Kong et. al., 2000) sulfides from two metamorphosed chondrites studied by instrumental neutron activation analysis (INAA) and ion probe. As shown, the level of REE in the sulfide phase determined by the ion probe is quite similar to that obtained by INAA. Although the concentrations of REE in the enstatite and the Fe, Si, Cr-rich inclusions are comparable to those in sulfide, estimates based on mass balance calculations show that the silicate inclusions would not noticeably contribute to the REE budget in sulfides (Kong et. al., 2000). These studies were supported by the RFBR 13-05-00493, OFI-M 13-05-12055, State Earth Division Program #4 and IGCP-599.

Simulation of geochemical processes responsible for the formation of the Zhezqazghan deposit

NASA Astrophysics Data System (ADS)

Ryzhenko, B. N.; Cherkasova, E. V.

2014-05-01

Physicochemical computer simulation of water-rock systems at a temperature of 25-150°C and under a pressure of up to 600 bar has been carried out for quantitative description of the mineralization formation conditions at sandstone- and shale-hosted copper deposits. The simulation is based on geological and geochemical information concerning the Zhezqazghan deposit and considers (i) a source of ore matter, (ii) composition of the fluid that transfers ore matter to the ore formation zone, and (iii) factors of ore concentration. It has been shown that extraction of copper from minerals of rocks and its accumulation in aqueous solution are optimal at a high mass ratio of rock to water (R/W > 10), Eh of +200 to -100 mV, and an obligatory content of chloride ions in the aqueous phase. The averaged ore-bearing fluid Cl95SO44//Ca50(Na + K)30Mg19 (eq %), pH ˜ 4, mineralization of up to 400 g/L, is formed by the interaction of red sandstone beds with a sedimentogenic brine (a product of metamorphism of seawater in carbonate rocks enriched in organic matter). The ore concentration proceeds in the course of cooling from 150 to 50°C during filtration of ore-bearing fluid through red sandstone beds in the rock-water system thermodynamically opened with respect to the reductive components.

Potential for cobalt recovery from lateritic ores in Europe

NASA Astrophysics Data System (ADS)

Herrington, R.

2012-04-01

Cobalt is one of the 'critical metals' identified under the EU Raw Materials Initiative. Annually the global mine production of cobalt is around 55,000 tonnes,with Europe's industries consuming around 30% of that figure. Currently Europe produces around 27 tonnes of cobalt from mines in Finland although new capacity is planned. Co-bearing nickel laterite ores being mined in Greece, Macedonia and Kosovo where the cobalt is currently not being recovered (ores have typical analyses of 0.055% Co and >1% Ni,). These ores are currently treated directly in pyrometallurgical plants to recover the contained nickel and this process means there is no separate cobalt product produced. Hydrometallurgical treatment of mineralogically suitable laterite ores can recover the cobalt; for example Cuba recovers 3,500 tonnes of cobalt from its laterite mining operations, which are of a similar scale to the current European operations. Implementation of hydrometallurgical techniques is in its infancy in Europe with one deposit in Turkey planning to use atmospheric heap leaching to recover nickel and copper from oxide-dominated ores. More widespread implementation of these methods to mineralogically suitable ore types could unlock the highly significant undeveloped resources (with metal contents >0.04% Co and >1% Ni), which have been defined throughout the Balkans eastwards into Turkey. At a conservative estimate, this region has the potential to supply up to 30% of the EU cobalt requirements.

Bog iron formation in the Nassawango Creek watershed, Maryland, USA

USGS Publications Warehouse

Bricker, O.P.; Newell, Wayne L.; Simon, N.S.; ,

2004-01-01

The Nassawango bog ores in the modern environment for surficial geochemical processes were studied. The formation of Nassawango bog ores was suggested to be due to inorganic oxidation when groundwater rich in ferrous iron emerges into the oxic, surficial environment. It was suggested that the process, providing a phosphorus sink, may be an unrecognized benefit for mitigating nutrient loading from agricultural lands. It is found that without the effect of iron fixing bacteria, bog deposites could not form at significant rates.

Generation of copper rich metallic phases from waste printed circuit boards.

PubMed

Cayumil, R; Khanna, R; Ikram-Ul-Haq, M; Rajarao, R; Hill, A; Sahajwalla, V

2014-10-01

The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containing significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150°C under argon gas flowing at 1L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally sustainable solution to the management of waste products. Copyright © 2014 Elsevier Ltd. All rights reserved.

Enrichment Wastes' Processing of Manganiferous Ores with the Use of Mechanochemical Methods

ERIC Educational Resources Information Center

Kubekova, Sholpan N.; Kapralova, Viktoria I.; Ibraimova, Gulnur T.; Batyrbayeva, Aigul A.

2016-01-01

The aim of the research is the study of the chemical and phase composition of enrichment wastes of manganiferous ore in Ushkatyn-III deposit and the synthesis of new materials by mechanochemical activation and subsequent heat treatment of the mechanical activation products. The use of XFA, infrared spectroscopy and electron probe microanalysis…

The Other-Race Effect in Infancy: Evidence Using a Morphing Technique

ERIC Educational Resources Information Center

Hayden, Angela; Bhatt, Ramesh S.; Joseph, Jane E.; Tanaka, James W.

2007-01-01

Human adults are more accurate at discriminating faces from their own race than faces from another race. This "other-race effect" (ORE) has been characterized as a reflection of face processing specialization arising from differential experience with own-race faces. We examined whether 3.5-month-old infants exhibit ORE using morphed faces on which…

The Role of Experience during Childhood in Shaping the Other-Race Effect

ERIC Educational Resources Information Center

de Heering, Adelaide; de Liedekerke, Claire; Deboni, Malorie; Rossion, Bruno

2010-01-01

It is well known that adults' face recognition is characterized by an "other-race effect" (ORE; see Meissner & Brigham, 2001), but few studies have investigated this ORE during the development of the face processing system. Here we examined the role of experience with other-race faces during childhood by testing a group of 6- to…

Training with Own-Race Faces Can Improve Processing of Other-Race Faces: Evidence from Developmental Prosopagnosia

ERIC Educational Resources Information Center

DeGutis, Joseph; DeNicola, Cristopher; Zink, Tyler; McGlinchey, Regina; Milberg, William

2011-01-01

Faces of one's own race are discriminated and recognized more accurately than faces of an other race (other-race effect--ORE). Studies have employed several methods to enhance individuation and recognition of other-race faces and reduce the ORE, including intensive perceptual training with other-race faces and explicitly instructing participants…

Effect of temperature on porosity of iron ore sinter with biochar derived from EFB

NASA Astrophysics Data System (ADS)

Purwanto, H.; Rozhan, A. N.; Zakiyuddin, A.; Mohamad, A. S.

2018-01-01

In this research, the replacement of fossil fuel energy (coke) with oil palm empty fruit bunch as a potential energy in sintering of iron ore was investigated. Carbon derived biomass has been produced by using oil palm empty fruit bunch by heat treatment process. In the present investigation, sintering process was carried out by heating the mixed iron ore and biochar at various temperatures. The apparent density and porosity for iron sinter show a significant increase and gradual decrement as the temperature increase, respectively. The porosity of iron sinter shows a gradual decrement from 950 °C to 1050 °C but up to 1150 °C it shows a significant decrement about 44%. Inferring to the micrograph, the agglomeration and assimilation of sinter at high temperature is better compared with low sintering temperature.

Enhancement of Au-Ag-Te contents in tellurium-bearing ore minerals via bioleaching

NASA Astrophysics Data System (ADS)

Choi, Nag-Choul; Cho, Kang Hee; Kim, Bong Ju; Lee, Soonjae; Park, Cheon Young

2018-03-01

The purpose of this study was to enhance the content of valuable metals, such as Au, Ag, and Te, in tellurium-bearing minerals via bioleaching. The ore samples composed of invisible Au and Au paragenesis minerals (such as pyrite, chalcopyrite, sphalerite and galena) in combination with tellurium-bearing minerals (hessite, sylvanite and Tellurobismuthite) were studied. Indigenous microbes from mine drainage were isolated and identified as Acidithiobacillus ferrooxidans, which were used in bioleaching after adaption to copper. The effect of the microbial adaption on the bioleaching performance was then compared with the results produced by the non-adaptive process. The microbial adaption enhanced the Au-Ag-Te contents in biological leaching of tellurium-bearing ore minerals. This suggests that bioleaching with adapted microbes can be used both as a pretreatment and in the main recovery processes of valuable metals.

Experimental research on the behavior of the pneumatic transport of fine-grained iron

NASA Astrophysics Data System (ADS)

Andrei, V.; Hritac, M.; Constantin, N.; Dobrescu, C.

2017-01-01

Mixed injection of fine-grained iron ore and pulverized coal in the furnace, involves determining the behavior of these materials during pneumatic transport in a dense state through the pipe and setting possibilities for adjusting the flow rate of material transported with the corresponding values of the process. Parameters of the pneumatic transport were determined for the main types of iron ore and chalk used in Arcelor Mittal Galati. Outside the intended purpose of injecting iron ore and flux, it was considered also the experimental check of the possibility for injecting ilmenite in the furnace for crucible protection purpose. The possibility of injecting cinder mill into the furnace was also considered. Injecting cinder could be taken into account for the recycling of ferrous waste in the furnace, also as additive for intensifying the combustion process around the tuyeres.

Raman Spectroscopic Characterisation of Australian Banded Iron Formation and Iron Ore

NASA Astrophysics Data System (ADS)

Wells, M. A.; Ramanaidou, E. R.

2012-04-01

In Australia and world-wide over the past 5-10 years, declining reserves of premium, high-grade (>64% Fe), low-P bearing iron ore, have seen iron ore producers increase their utilisation of lower Fe-grade, higher P/Al/Si ore. In Australia, the channel iron deposits (CID), bedded iron deposits (BID) and, more recently, BIF-derived magnetite iron deposits (MID) have seen increased usage driven mainly by the increased demand from Chinese steel mills (Ramanaidou and Wells, 2011). Efficient exploitation and processing of these lower-grade iron ores requires a detailed understanding of their iron oxide and gangue mineralogy and geochemistry. The common Fe-bearing minerals (e.g., hematite, magnetite, goethite and kenomagnetite) in these deposits, as well as gangue minerals such as quartz and carbonates, are all strongly Raman active (e.g., de Faria et al., 1997). Their distinct Raman spectra enable them to be easily detected and mapped in situ in either unprepared material or samples prepared as polished blocks. In this paper, using representative examples of Australian CID ore, martite-goethite bedded iron deposit (BID) ore and banded iron formation (BIF) examined as polished blocks, we present a range of Raman spectra of the key iron ore minerals, and discuss how Raman spectroscopy can be applied to characterising iron ore mineralogy. Raman imaging micrographs, obtained using a StreamLine Plus Raman imaging system, clearly identified the main Fe-oxide and gangue components in the CID, BID and BIF samples when compared to optical micrographs. Raman analysis enabled the unequivocal identification of diamond in the CID ore as a contaminant from the polishing paste used to prepare the sample, and confirmed the presence of hematite in the BID ore in the form of martite, which can be morphologically similar to magnetite and, thus, difficult to otherwise distinguish. Image analysis of Raman mineral maps could be used to quantify mineral abundance based on the number of 'pixels' identified for each phase normalised to the total number of 'pixels' for each area scanned. Shifts in the main phonon lines of goethite and hematite mapped in the CID samples examined were used to estimate the Al substitution in these phases (e.g., Ramanaidou et al. 1996) which were consistent with electron microprobe data. The Raman data demonstrated the Al-free nature of hematite (0.5 mol% Al) and showed that goethite in the CID cortex was more Al-rich (10 mol%) than goethite in the CID matrix (3 mol% Al). Shifts in the excitation bands of carbonate mapped in the BIF sample were well related to the Mg content of Fe-carbonate, based on the work of Rividi et al. (2010) and confirmed by in situ spot analysis using energy dispersive spectroscopy (EDS) and scanning electron microscopy (SEM). This data confirmed the first world-wide occurrence of a high Mg-bearing siderite (pistomesite) in BIF. Detailed, in situ characterisation of the iron oxide and gangue mineralogy of iron ore deposits as provided by Raman spectroscopy provides a step change to current characterisation methods. Understanding and defining their mineralogy and geochemistry is critical in developing strategies to best manage and process existing BID and CID ores, as well as the newly emerging MID ores.

Study on copper kinetics in processing sulphide ore mixed with copper and zinc with sulfuric acid leaching under pressure

NASA Astrophysics Data System (ADS)

Wen-bo, LUO; Ji-kun, WANG; Yin, GAN

2018-01-01

Sulphide ore mixed with copper and zinc is processed with pressure acid leaching. Research is conducted on the copper kinetic. The stirring rate is set at 600 rpm which could eliminate the influence of external diffusions. Research is conducted on the factors affecting the copper leaching kinetic are temperature, pressure, concentration of sulfuric acid, particle size. The result shows that the apparent activity energy is 50.7 KJ/mol. We could determine that the copper leaching process is shrinking core model of chemical reaction control and work out the leaching equation.

Kinetic energy of Ps formed by Ore mechanism in Ar gas

NASA Astrophysics Data System (ADS)

Sano, Yosuke; Kino, Yasushi; Oka, Toshitaka; Sekine, Tsutomu

2015-06-01

In order to investigate kinetic energy of positronium(Ps) formed by Ore mechanism, we performed positron annihilation age-momentum correlation (AMOC) measurements in Argas for 5.0 MPa and 7.5 MPa at room temperature. From the time dependence of Doppler broadening of para-Ps (p-Ps) self-annihilation gramma-ray component, we observed Ps slowing down process. Using a simple slowing down model, we obtained the initial kinetic energy of Ps formed by Ore mechanism and Ps-Armomentum transfer cross section. The initial kinetic energy was 3.9 eV which was higher than the kinetic energy of Ps formed at the upper limit of Ore gap. The momentum transfer cross section was 0.019 ± 0.010 nm2 in between 1 eV and 3.9 eV, and was close to the theoretical calculation.

Coal-oil gold agglomeration assisted flotation to recover gold from refractory ore

NASA Astrophysics Data System (ADS)

Otsuki, A.; Yue, C.

2017-07-01

This study aimed to investigate the applicability of coal-oil gold agglomeration (CGA) assisted flotation to recover gold from a refractory ore. The ore with the grade of 2-5 g/t was tested with the CGA-flotation process in six different size fractions from 38 to 300 urn using different collector types and dosages. In addition, the flotation without CGA was performed under the same condition for comparison. The results showed that the higher gold grade and recovery were achieved by applying the CGA-flotation, compared with the flotation without CGA. More than 20-60 times grade increase from the head grade was obtained with CGA-flotation. The elemental analysis of gold and sulphur explained their relationship with gold recovery. The results well indicated the applicability of CGA to upgrade the refractory gold ore.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-06-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Recovery of Vanadium from Magnetite Ore Using Direct Acid Leaching: Optimization of Parameters by Plackett-Burman and Response Surface Methodologies

NASA Astrophysics Data System (ADS)

Nejad, Davood Ghoddocy; Khanchi, Ali Reza; Taghizadeh, Majid

2018-03-01

Recovery of vanadium from magnetite ore by direct acid leaching is discussed. The proposed process, which employs a mixture of nitric and sulfuric acids, avoids pyrometallurgical treatments since such treatment consumes a high amount of energy. To determine the optimum conditions of vanadium recovery, the leaching process is optimized through Plackett-Burman (P-B) design and response surface methodology (RSM). In this respect, temperature (80-95°C), liquid to solid ratio (L/S) (3-10 mL g-1), sulfuric acid concentration (3-6 M), nitric acid concentration (5-10 vol.%) and time (4-8 h) are considered as the independent variables. According to the P-B approach, temperature and acid concentrations are, respectively, the most effective parameters in the leaching process. These parameters are optimized using RSM to maximize recovery of vanadium by direct acid leaching. In this way, 86.7% of vanadium can be extracted from magnetic ore.

Risk evaluation of uranium mining: A geochemical inverse modelling approach

NASA Astrophysics Data System (ADS)

Rillard, J.; Zuddas, P.; Scislewski, A.

2011-12-01

It is well known that uranium extraction operations can increase risks linked to radiation exposure. The toxicity of uranium and associated heavy metals is the main environmental concern regarding exploitation and processing of U-ore. In areas where U mining is planned, a careful assessment of toxic and radioactive element concentrations is recommended before the start of mining activities. A background evaluation of harmful elements is important in order to prevent and/or quantify future water contamination resulting from possible migration of toxic metals coming from ore and waste water interaction. Controlled leaching experiments were carried out to investigate processes of ore and waste (leached ore) degradation, using samples from the uranium exploitation site located in Caetité-Bahia, Brazil. In experiments in which the reaction of waste with water was tested, we found that the water had low pH and high levels of sulphates and aluminium. On the other hand, in experiments in which ore was tested, the water had a chemical composition comparable to natural water found in the region of Caetité. On the basis of our experiments, we suggest that waste resulting from sulphuric acid treatment can induce acidification and salinization of surface and ground water. For this reason proper storage of waste is imperative. As a tool to evaluate the risks, a geochemical inverse modelling approach was developed to estimate the water-mineral interaction involving the presence of toxic elements. We used a method earlier described by Scislewski and Zuddas 2010 (Geochim. Cosmochim. Acta 74, 6996-7007) in which the reactive surface area of mineral dissolution can be estimated. We found that the reactive surface area of rock parent minerals is not constant during time but varies according to several orders of magnitude in only two months of interaction. We propose that parent mineral heterogeneity and particularly, neogenic phase formation may explain the observed variation of the reactive mineral surface area. The formation of coatings on dissolving mineral surfaces significantly reduces the amount of surface available to react with fluids. Our results show that negatively charged ion complexes, responsible for U transport, decreases when alkalinity and rock buffer capacity is similarly lower. Carbonate ion pairs however, may increase U mobility when radionuclide concentration is high and rock buffer capacity is low. The present work helps to orient future monitoring of this site in Brazil as well as of other sites where uranium is linked to igneous rock formations, without the presence of sulphides. Monitoring SO4 migration (in acidic leaching uranium sites) seems to be an efficient and simple way to track different hazards, especially in tropical conditions, where the succession of dry and wet periods increases the weathering action of the residual H2SO4. Nevertheless, models of risk evaluation should take into account reactive surface areas and neogenic minerals since they determine the U ion complex formation, which in turn, controls uranium mobility in natural systems. Keywords: uranium mining, reactive mineral surface area, uranium complexes, inverse modelling approach, risk evaluation

Chromium speciation and fractionation in ground and surface waters in the vicinity of chromite ore processing residue disposal sites.

PubMed

Farmer, John G; Thomas, Rhodri P; Graham, Margaret C; Geelhoed, Jeanine S; Lumsdon, David G; Paterson, Edward

2002-04-01

Chromium concentrations of up to 91 mg l(-1) were found by ICP-OES for ground water from nine boreholes at four landfill sites in an area of S.E. Glasgow/S. Lanarkshire where high-lime chromite ore processing residue (COPR) from a local chemical works had been deposited from 1830 to 1968. Surface water concentrations of up to 6.7 mg l(-1) in a local tributary stream fell to 0.11 mg l(-1) in the River Clyde. Two independent techniques of complexation/colorimetry and speciated isotope dilution mass spectrometry (SIDMS) showed that Cr was predominantly (>90%) in hexavalent form (CrVI) as CrO4(2-), as anticipated at the high pH (7.5-12.5) of the sites. Some differences between the implied and directly determined concentrations of dissolved CrIII, however, appeared related to the total organic carbon (TOC) content. This was most significant for the ground water from one borehole that had the highest TOC concentration of 300 mg l(-1) and at which < 3% of Cr was in the form of CrVI. Subsequent ultrafiltration produced significant decreases in Cr concentration with decreasing size fractions, e.g. <0.45 microm, < 100 kDa, <30 kDa and < 1 kDa by the tangential-flow method. As this appeared related more to concentrations of humic substances than of TOC per se, horizontal bed gel electrophoresis of freeze-dried ultrafilter retentates was carried out to further characterise the CrIII-organic complex. This showed for the main Cr-containing fraction, 100 kDa-0.45 microm, that the Cr was associated with a dark brown band characteristic of organic (humic) matter. Comparison of gel electrophoresis and FTIR results for ultrafilter retentates of ground water from this borehole with those for a borehole at another site where CrVI predominated suggested the influence of carboxylate groups, both in reducing CrVI and in forming soluble CrIII-humic complexes. The implications of this for remediation strategies (especially those based on the addition of organic matter) designed to reduce highly mobile and carcinogenic Cr(VI)O4(2-) to the much less harmful CrIII as insoluble Cr(OH)3 are discussed.

End-of-life vehicle recycling : state of the art of resource recovery from shredder residue.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Jody, B. J.; Daniels, E. J.; Energy Systems

Each year, more than 50 million vehicles reach the end of their service life throughout the world. More than 95% of these vehicles enter a comprehensive recycling infrastructure that includes auto parts recyclers/dismantlers, remanufacturers, and material recyclers (shredders). Today, about 75% of automotive materials are profitably recycled via (1) parts reuse and parts and components remanufacturing and (2) ultimately by the scrap processing (shredding) industry. The process by which the scrap processors recover metal scrap from automobiles involves shredding the obsolete automobiles, along with other obsolete metal-containing products (such as white goods, industrial scrap, and demolition debris), and recovering themore » metals from the shredded material. The single largest source of recycled ferrous scrap for the iron and steel industry is obsolete automobiles. The non-metallic fraction that remains after the metals are recovered from the shredded materials (about 25% of the weight of the vehicle)--commonly called shredder residue--is disposed of in landfills. Over the past 10 to 15 years, a significant amount of research and development has been undertaken to enhance the recycle rate of end-of-life vehicles (ELVs), including enhancing dismantling techniques and improving remanufacturing operations. However, most of the effort has focused on developing technology to recover materials, such as polymers, from shredder residue. To make future vehicles more energy efficient, more lighter-weight materials--primarily polymers and polymer composites--will be used in manufacturing these vehicles. These materials increase the percentage of shredder residue that must be disposed of, compared with the percentage of metals. Therefore, as the complexity of automotive materials and systems increases, new technologies will be required to sustain and maximize the ultimate recycling of these materials and systems at end-of-life. Argonne National Laboratory (Argonne), in cooperation with the Vehicle Recycling Partnership (VRP) and the American Plastics Council (APC), is working to develop technology for recycling materials from shredder residue. Several other organizations worldwide are also working on developing technology for recycling shredder residue. Without a commercially viable shredder industry, our nation may face greater environmental challenges and a decreased supply of quality scrap and be forced to turn to primary ores for the production of finished metals. This document presents a review of the state of the art in shredder residue recycling. Available technologies and emerging technologies for the recycling of materials from shredder residue are discussed.« less

Reducing acid leaching of manganiferous ore: Effect of the iron removal operation on solid waste disposal

DOE Office of Scientific and Technical Information (OSTI.GOV)

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca

2009-01-15

The process of reducing acid leaching of manganiferous ore is aimed at the extraction of manganese from low grade manganese ores. This work is focused on the iron removal operation. The following items have been considered in order to investigate the effect of the main operating conditions on solid waste disposal and on the process costs: (i) type and quantity of the base agent used for iron precipitation, (ii) effective need of leaching waste separation prior to the iron removal operation, (iii) presence of a second leaching stage with the roasted ore, which might also act as a preliminary ironmore » removal step, and (iv) effect of tailings washing on the solid waste classification. Different base compounds have been tested, including CaO, CaCO{sub 3}, NaOH, and Na{sub 2}CO{sub 3}. The latter gave the best results concerning both the precipitation process kinetics and the reagent consumption. The filtration of the liquor leach prior to iron removal was not necessary, implying significant savings in capital costs. A reduction of chemical consumption and an increase of manganese concentration in the solution were obtained by introducing secondary leaching tests with the previously roasted ore; this additional step was introduced without a significant decrease of global manganese extraction yield. Finally, toxicity characteristic leaching procedure (TCLP) tests carried out on the leaching solid waste showed: (i) a reduction of arsenic mobility in the presence of iron precipitates, and (ii) the need for a washing step in order to produce a waste that is classifiable as not dangerous, taking into consideration the existing Environmental National Laws.« less

Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

PubMed Central

Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; Pattrick, Richard A.D.; Thomas, Russell A.P.; Kalin, Robert; Lloyd, Jonathan R.

2015-01-01

Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ∼25% (BnM) and ∼50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions. In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ⩾5% w/w BnM or ⩾1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable capacity for the remediation of COPR related Cr(VI) contamination, with the synthetic nZVI demonstrating greater reactivity than the BnM. However, the biosynthesized BnM was also capable of significant Cr(VI) reduction and demonstrated a greater efficiency for the coupling of its electrons towards Cr(VI) reduction than the nZVI. PMID:26109747

Biogenic nano-magnetite and nano-zero valent iron treatment of alkaline Cr(VI) leachate and chromite ore processing residue

DOE PAGES

Watts, Mathew P.; Coker, Victoria S.; Parry, Stephen A.; ...

2014-12-11

Highly reactive nano-scale biogenic magnetite (BnM), synthesized by the Fe(III)-reducing bacterium Geobacter sulfurreducens, was tested for the potential to remediate alkaline Cr(VI) contaminated waters associated with chromite ore processing residue (COPR). The performance of this biomaterial, targeting aqueous Cr(VI) removal, was compared to a synthetic alternative, nano-scale zero valent iron (nZVI). Samples of highly contaminated alkaline groundwater and COPR solid waste were obtained from a contaminated site in Glasgow, UK. During batch reactivity tests, Cr(VI) removal from groundwater was inhibited by ~25% (BnM) and ~50% (nZVI) when compared to the treatment of less chemically complex model pH 12 Cr(VI) solutions.more » In both the model Cr(VI) solutions and contaminated groundwater experiments the surface of the nanoparticles became passivated, preventing complete coupling of their available electrons to Cr(VI) reduction. To investigate this process, the surfaces of the reacted samples were analyzed by TEM-EDX, XAS and XPS, confirming Cr(VI) reduction to the less soluble Cr(III) on the nanoparticle surface. In groundwater reacted samples the presence of Ca, Si and S was also noted on the surface of the nanoparticles, and is likely responsible for earlier onset of passivation. Treatment of the solid COPR material in contact with water, by addition of increasing weight % of the nanoparticles, resulted in a decrease in aqueous Cr(VI) concentrations to below detection limits, via the addition of ≥5% w/w BnM or ≥1% w/w nZVI. XANES analysis of the Cr K edge, showed that the % Cr(VI) in the COPR dropped from 26% to a minimum of 4–7% by the addition of 5% w/w BnM or 2% w/w nZVI, with higher additions unable to reduce the remaining Cr(VI). The treated materials exhibited minimal re-mobilization of soluble Cr(VI) by re-equilibration with atmospheric oxygen, with the bulk of the Cr remaining in the solid fraction. Both nanoparticles exhibited a considerable capacity for the remediation of COPR related Cr(VI) contamination, with the synthetic nZVI demonstrating greater reactivity than the BnM. Furthermore, the biosynthesized BnM was also capable of significant Cr(VI) reduction and demonstrated a greater efficiency for the coupling of its electrons towards Cr(VI) reduction than the nZVI.« less

Experimental Study on the Coupling Mechanism of Early-strength Backfill and Rock

NASA Astrophysics Data System (ADS)

Wang, Mingxu

2017-11-01

In order to study the interaction mechanism between the ore rock and backfill at the early stage, paraffin is chosen as the cementing agent. Based on the damage mechanics and fractal theory, the interaction mechanism between the ore rock and backfill is characterized by the relevant tests on the complex of proportioned ore rock and backfill with resistance strain gauge, crack propagation, microscopic imaging and AE. The experimental results showed that: 1) Through the axial loading test, compared with the early strength of the cemented filling and paraffin mechanical deformation characteristics, the stress and strain curves of the two had a common linear deformation law, while in the early strength of the filling elastic capacity strong, with a certain degree of resilience. 2) The bearing capacity of the backfill was weak, but the deformation ability was strong. During the bearing process, the deformation of the upper load was mainly caused by the ore rock, which leaded to the damage of the rock. 3) The distribution of AE points during the co-carrying of the filling and the ore rock was monitored by the acoustic emission instrument. The damage occurred mainly in the contact zone between the backfill and the ore rock zone. The corresponding AE point distribution also validated the crack happening.

Dzhezkazgan and associated sandstone copper deposits of the Chu-Sarysu basin, Central Kazakhstan

USGS Publications Warehouse

Box, Stephen E.; Seltmann, Reimar; Zientek, Michael L.; Syusyura, Boris; Creaser, Robert A.; Dolgopolova, Alla

2012-01-01

Sandstone-hosted copper (sandstone Cu) deposits occur within a 200-km reach of the northern Chu-Sarysu basin of central Kazakhstan (Dzhezkazgan and Zhaman-Aibat deposits, and the Zhilandy group of deposits). The deposits consist of Cu sulfide minerals as intergranular cement and grain replacement in 10 ore-bearing members of sandstone and conglomerate within a 600- to 1,000-m thick Pennsylvanian fluvial red-bed sequence. Copper metal content of the deposits ranges from 22 million metric tons (Mt, Dzehzkazgan) to 0.13Mt (Karashoshak in the Zhilandy group), with average grades of 0.85 to 1.7% Cu and significant values for silver (Ag) and rhenium (Re). Broader zones of iron reduction (bleaching) of sandstones and conglomerates of the red-bed sequence extend over 10 km beyond each of the deposits along E-NE-trending anticlines, which began to form in the Pennsylvanian. The bleached zones and organic residues within them are remnants of ormer petroleum fluid accumulations trapped by these anticlines. Deposit sites along these F1anticlines are localized at and adjacent to the intersections of nearly orthogonal N-NW-trending F2synclines. These structural lows served to guide the flow of dense ore brines across the petroleum-bearing anticlines, resulting in ore sulfide precipitation where the two fluids mixed. The ore brine was sourced either from the overlying Early Permian lacustrine evaporitic basin, whose depocenter occurs between the major deposits, or from underlying Upper Devonian marine evaporites. Sulfur isotopes indicate biologic reduction of sulfate but do not resolve whether the sulfate was contributed from the brine or from the petroleum fluids. New Re-Os age dates of Cu sulfides from the Dzhezkazgan deposit indicate that mineralization took place between 299 to 309 Ma near the Pennsylvanian-Permian age boundary. At the Dzhezkazgan and some Zhilandy deposits, F2fold deformation continued after ore deposition. Copper orebodies in Lower Permian shale near the Zhaman-Aibat deposit indicate that at least some of the mineralization there is younger than at Dzhezkazgan, consistent with the Re-Os age and with differences in their ore Pb isotopes.

Separation of thorium ions from wolframite and scandium concentrates using graphene oxide.

PubMed

Jankovský, Ondřej; Sedmidubský, David; Šimek, Petr; Klímová, Kateřina; Bouša, Daniel; Boothroyd, Chris; Macková, Anna; Sofer, Zdeněk

2015-10-14

The separation of rare metals from the ores and commercially available compounds is an important issue due to the need of their high purity in advanced materials and devices. Important examples of two highly important elements that co-exist in the ores are scandium and thorium. Scandium containing ores and consequently also commercially available scandium compounds often contain traces of thorium which is very difficult to separate. We used graphene oxide for the selective sorption of thorium ions from scandium and thorium mixtures originating from the mined ores as well as from commercially available scandium salts. Our results showed that graphene oxide has an extreme affinity towards thorium ions. After the sorption process the graphene oxide contained over 20 wt% of thorium while the amount of scandium sorbed on GO was very low. This phenomenon of high sorption selectivity of graphene oxide can be applied in industry for the purification of various chemicals containing scandium and for separation of thorium containing mixtures. Alternatively, this methodology can be used for preconcentration of thorium from low-grade ores and its further use in the new generation of nuclear reactors.

40 CFR 440.103 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2010 CFR

2010-07-01

... that use dump, heap, in situ leach or vat-leach processes to extract copper from ores or ore waste... achievable (BAT). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing... achievable (BAT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

40 CFR 440.103 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2012 CFR

2012-07-01

... that use dump, heap, in situ leach or vat-leach processes to extract copper from ores or ore waste... economically achievable (BAT). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32... economically achievable (BAT): (a) The concentration of pollutants discharged in mine drainage from mines that...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach... operations other than placer deposits; (2) Mills that use the froth-flotation process alone or in conjunction... not apply to discharges from the Quartz Hill Molybdenum Project in the Tongass National Forest, Alaska...

40 CFR 440.100 - Applicability; description of the copper, lead, zinc, gold, silver, and molybdenum ores subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... any combination of these ores; (3) Mines and mills that use dump, heap, in-situ leach, or vat-leach... operations other than placer deposits; (2) Mills that use the froth-flotation process alone or in conjunction... not apply to discharges from the Quartz Hill Molybdenum Project in the Tongass National Forest, Alaska...

40 CFR 440.103 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2014 CFR

2014-07-01

... that use dump, heap, in situ leach or vat-leach processes to extract copper from ores or ore waste... economically achievable (BAT). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32... economically achievable (BAT): (a) The concentration of pollutants discharged in mine drainage from mines that...

40 CFR 440.103 - Effluent limitations representing the degree of effluent reduction attainable by the application...

Code of Federal Regulations, 2011 CFR

2011-07-01

... that use dump, heap, in situ leach or vat-leach processes to extract copper from ores or ore waste... achievable (BAT). Except as provided in subpart L of this part and 40 CFR 125.30 through 125.32, any existing... achievable (BAT): (a) The concentration of pollutants discharged in mine drainage from mines that produce...

Upgrading nickel content of limonite nickel ore through pelletization, selective reduction and magnetic separation

NASA Astrophysics Data System (ADS)

Mayangsari, W.; Prasetyo, A. B.; Prasetiyo, Puguh

2018-04-01

Limonite nickel ore has potency to utilize as raw material for ferronickel or nickel matte, since it has low grade nickel content, thus process development is needed to find the acceptable process for upgrading nickel. The aim of this research is to determine upgrading of Ni content as result of selective reduction of limonite nickel pellet continued by magnetic separation as effect of temperature and time reduction as well as coal and CaSO4 addition. There are four steps to perform this research, such as preparation including characterization of raw ore and pelletization, selective reduction, magnetic separation and characterization of products by using AAS, XRD and SEM. Based on the result study, pellet form can upgrade 77.78% higher than powder form. Upgrading of Ni and Fe content was up to 3fold and 1.5fold respectively from raw ore used when reduced at 1100°C for 60 minutes with composition of coal and CaSO4, both 10%. The excess of CaSO4 addition caused fayalite formation. Moreover, S2 from CaSO4 also support to reach low melting point and enlardge particle size of metal formed.

Geology and ore deposits of the Mahd Adh Dhahab District, Kingdom of Saudi Arabia

USGS Publications Warehouse

Luce, Robert W.; Bagdady, Abdulaziz; Roberts, Ralph Jackson

1976-01-01

The principal ore minerals are pyrite, chalcopyrite, sphalerite, galena, and minor tetrahedrite, argentite, and native gold and silver. The gold and silver occurs finely disseminated in the veins and in the altered selvages of the veins. Widespread potassic and propylitic alteration accompanied the ore-forming processes. Potassium feldspar was introduced during an early stage of vein formation. Isotopic analyses of lead in vein potassium feldspar and galena yield a model age of about 900-1050 million years with the possibility of the original lead source having been remobilized about 600 million years ago. Chlorite and carbonate are also prominent vein minerals.

Impact of Dust from Ore Processing Facilities on Rain Water Collection Tanks in a Tropical Environment—The Obvious Source “Ain’t Necessarily So”

PubMed Central

Gulson, Brian; Korsch, Michael; Bradshaw, Anthony

2016-01-01

Concerns have been expressed that dust from the minerals processing facilities at Karumba Queensland Australia have resulted in elevated lead (Pb) concentrations in rain water tanks. The ores derived from the Century mine some 304 km from the port. High precision Pb isotopic measurements on environmental samples have been undertaken to evaluate the source of Pb in rainwaters and acid digests from roof wipes and gutter wipes. There does not appear to be any relationship between sample location and the processing facility but samples from the area subject to the prevailing winds show the highest contribution of Century Pb. All gutter wipes (82 to 1270 µg Pb/wipe) have contributions of Century ore ranging from 87% to 96%. The contribution of Century ore to five roof wipes (22 to 88 µg Pb/wipe) ranges from 89% to 97% and in the other two samples there is a mix of Century and Broken Hill Pb. Three of the seven rainwater have contributions of Century ore Pb ranging from 33% to 75%. Two of the other four rainwater samples have the highest water Pb concentrations of 88 and 100 µg/L and their isotopic data show Broken Hill Pb contributions ranging from 77% to 80%. The source of the Broken Hill Pb is probably from the galvanized roofing material and/or brass fittings in the rainwater tanks. The discrimination between various sources is only detectable using high precision 204Pb-based isotopic ratios and not the now common inductively coupled plasma mass spectrometry (ICP-MS ) data presentations of the higher abundance isotopes 208Pb, 207Pb and 206Pb. Isotopic results for the waters demonstrate that apportioning blame where there is an obvious point source may not always be the correct conclusion. Nevertheless the isotopic data for the gutter wipes indicates that there was widespread contamination from the processing facilities throughout the town. PMID:26907319

Impact of Dust from Ore Processing Facilities on Rain Water Collection Tanks in a Tropical Environment--The Obvious Source "Ain't Necessarily So".

PubMed

Gulson, Brian; Korsch, Michael; Bradshaw, Anthony

2016-02-22

Concerns have been expressed that dust from the minerals processing facilities at Karumba Queensland Australia have resulted in elevated lead (Pb) concentrations in rain water tanks. The ores derived from the Century mine some 304 km from the port. High precision Pb isotopic measurements on environmental samples have been undertaken to evaluate the source of Pb in rainwaters and acid digests from roof wipes and gutter wipes. There does not appear to be any relationship between sample location and the processing facility but samples from the area subject to the prevailing winds show the highest contribution of Century Pb. All gutter wipes (82 to 1270 µg Pb/wipe) have contributions of Century ore ranging from 87% to 96%. The contribution of Century ore to five roof wipes (22 to 88 µg Pb/wipe) ranges from 89% to 97% and in the other two samples there is a mix of Century and Broken Hill Pb. Three of the seven rainwater have contributions of Century ore Pb ranging from 33% to 75%. Two of the other four rainwater samples have the highest water Pb concentrations of 88 and 100 µg/L and their isotopic data show Broken Hill Pb contributions ranging from 77% to 80%. The source of the Broken Hill Pb is probably from the galvanized roofing material and/or brass fittings in the rainwater tanks. The discrimination between various sources is only detectable using high precision (204)Pb-based isotopic ratios and not the now common inductively coupled plasma mass spectrometry (ICP-MS ) data presentations of the higher abundance isotopes (208)Pb, (207)Pb and (206)Pb. Isotopic results for the waters demonstrate that apportioning blame where there is an obvious point source may not always be the correct conclusion. Nevertheless the isotopic data for the gutter wipes indicates that there was widespread contamination from the processing facilities throughout the town.

Possible mechanism of horizontal overpressure generation of the Khibiny, Lovozero, and Kovdor ore clusters on the Kola Peninsula

NASA Astrophysics Data System (ADS)

Rebetsky, Yu. L.; Sim, L. A.; Kozyrev, A. A.

2017-07-01

The paper discusses questions related to the generation of increasing crustal horizontal compressive stresses compared to the idea of the standard gravitational state at the elastic stage or even from the prevalence of horizontal compression over vertical stress equal to the lithostatic pressure. We consider a variant of superfluous horizontal compression related to internal lithospheric processes occurrin in the crust of orogens, shields, and plates. The vertical ascending movements caused by these motions at the sole of the crust or the lithosphere pertain to these and the concomitant exogenic processes giving rise to denudation and, in particular, to erosion of the surfaces of forming rises. The residual stresses of the gravitational stressed state at the upper crust of the Kola Peninsula have been estimated for the first time. These calculations are based on the volume of sediments that have been deposited in Arctic seas beginning from the Mesozoic. The data speak to the possible level of residual horizontal compressive stresses up to 90 MPa in near-surface crustal units. This estimate is consistent with the results of in situ measurements that have been carried out at the Mining Institute of the Kola Science Center, Russian Academy of Sciences (RAS), for over 40 years. It is possible to forecast the horizontal stress gradient based on depth using our concept on the genesis of horizontal overpressure, and this forecasting is important for studying the formation of endogenic deposits.

Carbothermic Reduction of Nickeliferous Laterite Ores for Nickel Pig Iron Production in China: A Review

NASA Astrophysics Data System (ADS)

Rao, Mingjun; Li, Guanghui; Jiang, Tao; Luo, Jun; Zhang, Yuanbo; Fan, Xiaohui

2013-11-01

Both the consumption and production of crude stainless steel in China rank first in the world. In 2011, the nickel production in China amounted to 446 kilotons, with the proportion of electrolytic nickel and nickel pig iron (NPI) registering 41.5% and 56.5%, respectively. NPI is a low-cost feedstock for stainless steel production when used as a substitute for electrolytic nickel. The existing commercial NPI production processes such as blast furnace smelting, rotary kiln-electric furnace smelting, and Krupp-Renn (Nipon Yakin Oheyama) processes are discussed. As low-temperature (below 1300°C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500°C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

Applied technology for mine waste water decontamination in the uranium ores extraction from Romania

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bejenaru, C.; Filip, G.; Vacariu, V.T.

1996-12-31

The exploitation of uranium ores in Romania is carried out in underground mines. In all exploited uranium deposits, mine waste waters results and will still result after the closure of uranium ore extraction activity. The mine waters are radioactively contaminated with uranium and its decay products being a hazard both for underground waters as for the environment. This paper present the results of research work carried out by authors for uranium elimination from waste waters as the problems involved during the exploitation process of the existent equipment as its maintenance in good experimental conditions. The main waste water characteristics aremore » discussed: solids as suspension, uranium, radium, mineral salts, pH, etc. The moist suitable way to eliminate uranium from mine waste waters is the ion exchange process based on ion exchangers in fluidized bed. A flowsheet is given with main advantages resulted.« less

Biotechnology in the management and resource recovery from metal bearing solid wastes: Recent advances.

PubMed

Sethurajan, Manivannan; van Hullebusch, Eric D; Nancharaiah, Yarlagadda V

2018-04-01

Solid metalliferous wastes (sludges, dusts, residues, slags, red mud and tailing wastes) originating from ferrous and non-ferrous metallurgical industries are a serious environmental threat, when waste management practices are not properly followed. Metalliferous wastes generated by metallurgical industries are promising resources for biotechnological extraction of metals. These wastes still contain significant amounts of valuable non-ferrous metals, sometimes precious metals and also rare earth elements. Elemental composition and mineralogy of the metallurgical wastes is dependent on the nature of mining site and composition of primary ores mined. Most of the metalliferous wastes are oxidized in nature and contain less/no reduced sulfidic minerals (which can be quite well processed by biohydrometallurgy). However, application of biohydrometallurgy is more challenging while extracting metals from metallurgical wastes that contain oxide minerals. In this review, origin, elemental composition and mineralogy of the metallurgical solid wastes are presented. Various bio-hydrometallurgical processes that can be considered for the extraction of non-ferrous metals from metal bearing solid wastes are reviewed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Radiological restrictions of using red mud as building material additive.

PubMed

Gu, Hannian; Wang, Ning; Liu, Shirong

2012-09-01

Red mud remains as residue from the processing of bauxite using different methods. The chemical composition of red mud varies widely with respect to the types of bauxite ore and processing parameters. Red mud samples from Guizhou, China, were investigated using a X-ray fluorescence spectroscope, a quadrupole inductively coupled plasma mass spectrometer and a electron probe micro-analyzer. The results showed that red mud consisted of eight main chemical components--CaO, Al(2)O(3), SiO(2), Fe(2)O(3), TiO(2), Na(2)O, K(2)O and MgO--and dozens of trace elements, including natural radioactive elements, such as uranium and thorium. Gamma spectrometric analysis showed that the values of internal exposure index I (Ra) and external exposure index I (γ) of Guizhou red mud were 1.1-2.4 and 2.3-3.5 respectively. Thus, it should not be used as a main building material indiscriminately. The amount of red mud from Guizhou when it is used for main building materials in China should be less than 28-44%.

Manipulation of a Senescence-Associated Gene Improves Fleshy Fruit Yield1[OPEN

PubMed Central

Gramegna, Giovanna; Trench, Bruna A.; Alves, Frederico R.R.; Silva, Eder M.; Silva, Geraldo F.F.; Thirumalaikumar, Venkatesh P.; Lupi, Alessandra C.D.; Demarco, Diego; Nogueira, Fabio T.S.; Freschi, Luciano

2017-01-01

Senescence is the process that marks the end of a leaf’s lifespan. As it progresses, the massive macromolecular catabolism dismantles the chloroplasts and, consequently, decreases the photosynthetic capacity of these organs. Thus, senescence manipulation is a strategy to improve plant yield by extending the leaf’s photosynthetically active window of time. However, it remains to be addressed if this approach can improve fleshy fruit production and nutritional quality. One way to delay senescence initiation is by regulating key transcription factors (TFs) involved in triggering this process, such as the NAC TF ORESARA1 (ORE1). Here, three senescence-related NAC TFs from tomato (Solanum lycopersicum) were identified, namely SlORE1S02, SlORE1S03, and SlORE1S06. All three genes were shown to be responsive to senescence-inducing stimuli and posttranscriptionally regulated by the microRNA miR164. Moreover, the encoded proteins interacted physically with the chloroplast maintenance-related TF SlGLKs. This characterization led to the selection of a putative tomato ORE1 as target gene for RNA interference knockdown. Transgenic lines showed delayed senescence and enhanced carbon assimilation that, ultimately, increased the number of fruits and their total soluble solid content. Additionally, the fruit nutraceutical composition was enhanced. In conclusion, these data provide robust evidence that the manipulation of leaf senescence is an effective strategy for yield improvement in fleshy fruit-bearing species. PMID:28710129

Colloidal and physical transport textures exhibited by electrum and naumannite in bonanza epithermal veins from western USA, and their significance

USGS Publications Warehouse

Saunders, James A.; Vikre, Peter G.; Unger, Derick L.; Beasley, Lee

2010-01-01

It is reasonably clear that disequilibrium or “far-from equilibrium” conditions lead to the formation of silica colloids and their deposition in many epithermal deposits. This implies ore-forming solutions had elevated concentrations of dissolved silica, well in excess of amorphous silica saturation. We have previously demonstrated that such colloidal silica particles were deposited in epithermal veins as silica gels and opal, which may later progress along a path to crystallize into more thermodynamically favored (less-soluble) silica phases such as quartz and chalcedony. Also, in some deposits, amorphous silica is co-deposited with precious-metal minerals, such as electrum in the banded super-bonanza ores of the Sleeper deposit (NV). Ore-mineral textures from some western USA bonanza epithermal ores indicate that two precious-metal phases (electrum and naumannite, Ag2Se) form colloidal particles that are transported by ore-forming fluids and are deposited either by aggregation (by sticking to other precious metal-particles) to make dendrites, or are deposited on the “lee” side of protrusion along vein walls (or perhaps by both processes). We can infer by analogy to silica that this also implies that ore-forming solutions contained elevated (supersaturated) dissolved concentrations of both gold and silver that formed colloidal particles under disequilibrium (often chaotic) conditions. Thus physical transport and deposition textures seem to indicate the presence of strongly precious-metal-enriched ore forming fluids, which led to (not surprisingly) the bonanza grades of these remarkable ores. What causes such a precious-metal-rich solution is debatable, but that is the subject of our continued investigations.

Metallogeny by Trans-magmatic Fluids—Theoretical Analysis and Field Evidence

NASA Astrophysics Data System (ADS)

Luo, Zhaohua; Mo, Xuanxue; Lu, Xinxiang; Chen, Bihe; Ke, Shan; Hou, Zengqian; Jiang, Wan

This paper is aimed at introducing and developing the principle of Metallogenic Theory through Trans-magmatic Fluids (MTTF) proposed by the Russian Kozhinskii's school. Some fundamental problems of metallogeny are discussed on geodynamic bases. In this theory, the trans-magmatic fluid is interpreted as a moving fluid passing through magma which is not yet consolidated. The intensive wallrock alteration of most of hydrothermal ore systems suggests that large scale fluid flow accompanies metallogenesis. However, geological observations and experiments imply a very limited solubility of fluids in magmas. In addition, the close relationship between small igneous bodies and large ore systems together with the difficulty of fluids that from the wallrocks might enter a magmatic body, which is under high pressure and temperature, need also to be considered. Those ore-bearing fluids that originate from a deep fluid system, are independent of magmas. Experiments show rapid increases of the solubility of ore-forming elements or their compounds in hydrothermal fluids. Therefore, the essential prerequisites for mineralization are (1) large volumes of deep ore-bearing fluids with high concentration of metals, and (2) the large amounts of metal accumulation depend on the rapid ascent of the deep ore-bearing fluid. Magmas are the favorable medium for the ascending fluids, because these magmas provide conditions that prevent re-equilibrium between the fluid and the wallrocks at different deep levels. The fluids in turn, may provide the driving force for the rapid ascent of magmas. Therefore, the two systems act together to account for the close relationship between magmatism and metallogeny. According to this theory, the scale and location of an ore-forming process are decided by (1) the volumetric ratio of the magma and the fluid systems, (2) the ascending rate of the ore-bearing fluid, (3) the boundary conditions for metal accumulation and (4) the segregation of the fluid from the magma. The field investigations of copper-bearing Melanocratic Macrogranular Enclaves (MME) in the Qushui massif, Gangdise belt are very helpful for understanding of source, transport and precipitation of ore-forming materials. In this example, it can be seen that fluid-rich MMEs is the source of the ore-forming element copper. Copper is transported out from MMEs by the fluid, following dispersal in the granitic magma. The copper-bearing fluid is then transferred through the magma and induced to deposit mineralization elsewhere. These processes have been noted when comparing the metallogenic features in both MME in the Qushui massif and the porphyry copper deposits in Yulong, eastern Tibet. It is obvious that MTTF is a very important theory for metallogeny of endogenic deposits. Using this theory, many paradoxes in metallogenesis can be interpreted in easier manner.

Development of Technology for Enrichment of Silver Containing Ores

NASA Astrophysics Data System (ADS)

Shekiladze, Asmati; Kavtelashvili, Otari; Bagnashvili, Mamuka

2016-10-01

The progress of Georgian economics is substantially associated with a development of new deposits of mineral resources. Among them is the David-Gareji deposit where at present the intensive searching geological works are performed. The work goal involves the elaboration of the technology for processing of silver-containing quartz-barite ores. Without its development the mining of more valuable gold-polymetallic ores is impossible. Because of ore complexity silver and barite are considered in a common technological aspect. The investigations were carried out on the representative samples of quartz-barite ores containing 78-88 g/ton of silver and 27-29 % of silver is a nugget in the form of the simple sulphides and chlorides. The ore is characterized by fine coalescence of barite and ore-generating minerals. Non-ferrous metals haven't any industrial value because of their very low content. Therefore, for the processing of the ores under study the direct selective scheme of flotation enrichment was chosen and the formula of optimal reagent regime was elaborated. Potassium xanthogenate is used as a collector for flotation of silver minerals and pine oil- as a foaming agent. The effect of the pulp - pH and medium temperature on silver flotation was studied. It was established that the silver is actively floats in neutral medium. For barite flotation the various collectors were tested: sulfidezid cotton oil-soap stock, soaps of fatty acids and alkyl sulphates of C12 - C16 row, among the “Baritol” is the most efficient one. Depression of the barren rock was carried out by liquid glass in alkaline medium. The effect of pulp pH on barite flotation has been investigated. The best results were obtained at pH=8.5. The increase of the pulp alkalinity has no essential effect on the indexes of the barite enrichment. Conditional concentrate of the barite is obtained by two fold purification of the main flotation concentrate by the addition of the liquid glass to the re-purification operations. On the basis of laboratory investigations for silver-containing ores of David-Gareji deposit the technological scheme is recommended which implies the ore milling to 82 % class -074 mm, flotation of the silver minerals and the barite flotation from the tails of this operation by two-fold re-purification of the rough concentrate. The optimal parameters of the receipt of the reagent regime are: potassium butylxantogenate and pine oil-in the silver flotation; sodium carbonate, liquid glass, “Baritol”- in the barite main flotation and liquid glass in the repurification operations. Silver concentrate containing 680 g/ton of silver by extraction of 92.21% and barite concentrate, content - 92.11%, extraction - 81.85% are obtained.

Use of structural geology in exploration for and mining of sedimentary rock-hosted Au deposits

USGS Publications Warehouse

Peters, Stephen G.

2001-01-01

Structural geology is an important component in regional-, district- and orebody-scale exploration and development of sedimentary rock-hosted Au deposits.Identification of timing of important structural events in an ore district allows analysis and classification of fluid conduits and construction of genetic models for ore formation.The most practical uses of structural geology deal with measurement and definition of various elements that comprise orebodies, which can then be directly applied to ore-reserve estimation,ground control,grade control, safety issues,and mine planning.District- and regional-scale structural studies are directly applicable to long-term strategic planning,economic analysis,and land ownership. Orebodies in sedimentary rock-hosted Au deposits are discrete, hypogene, epigenetic masses usually hosted in a fault zone,breccia mass, or lithologic bed or unit. These attributes allow structural geology to be directly applied to the mining and exploration of sedimentary rock-hosted Au deposits. Internal constituents in orebodies reflect unique episodes relating to ore formation.The main internal constituents in orebodies are ore minerals, gangue, and alteration minerals that usually are mixed with one another in complex patterns, the relations among which may be used to interpret the processes of orebody formation and control.Controls of orebody location and shape usually are due to structural dilatant zones caused by changes in attitude, splays, lithologic contacts,and intersections of the host conduit or unit.In addition,conceptual parameters such as district fabric,predictable distances, and stacking also are used to understand the geometry of orebodies.Controls in ore districts and location and geometry of orebodies in ore districts can be predicted to various degrees by using a number of qualitative concepts such as internal and external orebody plunges,district plunge, district stacking, conduit classification, geochemical, geobarometric and geothermal gradients, and tectonic warps. These concepts have practical and empirical application in most mining districts where they are of use in the exploration for ore, but are of such broad and general application that they may not represent known or inferred ore formation processes. Close spatial relation among some sedimentary rock- hosted Au deposits and their host structures suggests that the structures and the orebodies are genetically linked because they may have shared the same developmental history. Examples of probable syn-deformational genesis and structural control of sedimentary rock-hosted Au deposits are in the large Betze deposit in the Carlin trend, Nevada and in the Lannigou, Jinlongshan, and Maanqiao Au deposits, China.

REM-containing silicate concentrates

NASA Astrophysics Data System (ADS)

Pavlov, V. F.; Shabanova, O. V.; Pavlov, I. V.; Pavlov, M. V.; Shabanov, A. V.

2016-01-01

A new method of advanced complex processing of ores containing rare-earth elements (REE) is proposed to obtain porous X-ray amorphous aluminosilicate material with a stable chemical composition which concentrates oxides of rare-earth metals (REM). The ferromanganese oxide ores of Chuktukon deposit (Krasnoyarsk Region, RF) were used for the experiment. The obtained aluminosilicate material is appropriate for treatment with 5 - 15% solutions of mineral acids to leach REM.

Rhenium, Molybdenum, Tungsten - Prospects for Production and Industrial Applications

DTIC Science & Technology

1998-06-18

concentrates from unique complex copper -containing porphyry deposit of the Almalyk region. The ore containing over 10 associated valuable constituents is...L.I.Ruzin, M .F.Sherem etyev ............................................... 71 Recovery of rhenium as by-product of treatment of molybdenite and copper ...for processing copper -molybdenum ores from "Erdenet- Ovoo" deposit S.Davaanyam, I.Sh.Sataev, Zh.Baatarkhuu, A.M.Desyatov, M.I.Khersonsky

[The characteristics of type I, III collagen and LN in pulmonary fibrosis induced by uranium ore dust in rats].

PubMed

Hu, Ying-chun; Luo, Zhen-hua; Yuan, Xing-jiang; Yang, Li-ping; Wang, Shou-feng; Li, Guang-yue; He, Xing-peng

2011-02-01

To explore the characteristics of LN and type I, III collagen in pulmonary fibrosis induced by uranium ore dust in rats. 60 adult Wistar rats were divided randomly into two groups, control group (30 rats) and uranium ore dust group (30 rats). Non-exposed intratracheal instillation method was used. Uranium ore dust group was exposed 20 mg/ml uranium ore dust suspension 1ml per rat, meanwhile control group was exposed normal saline 1ml per rat. Post-exposed the 7, 14, 21, 30 and 60 d, 6 rats in each group were killed randomly, lung tissue were collected. The pathological changes in lung tissue were observed by microscope using HE staining, the collagen I and III in lungs were observed by polarizing microscope using Biebrich scarlet staining. The expression of LN protein in lung tissue was observed by immunohistochemistry-SP. During lung fibrosis, a large amount of the proliferated I and III collagen in lungs were observed. Post-exposure to uranium ore dust, the characteristics in proliferated collagen in lungs were type I collagen deposited in lung interstitium mainly in the early stage. The area percentage of collagen I and III was increased significantly at 7, 14, 21, 30 and 60d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). The over expression of LN in the lung tissue were observed. The expression of LN was distributed in the lung tissue as thickening of the linear or cluster. The integral optical density of LN was increased significantly at 21, 30 and 60 d in the experimental group as compared with that in the control group (P < 0.05 or P < 0.01). After exposure to uranium ore dust, the characteristics in proliferated collagen in lungs are the type of I collagen deposited in lung interstitium mainly in the early stage, while the type of III collagen increase significantly at the later period. The overexpression of LN exists in the process of pulmonary fibrosis. It suggests that LN has a role effect in the process of pulmonary fibrosis.

Yttrium recovery from primary and secondary sources: A review of main hydrometallurgical processes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Innocenzi, Valentina, E-mail: valentina.innocenzi1@univaq.it; De Michelis, Ida; Kopacek, Bernd

2014-07-15

Highlights: • Review of the main hydrometallurgical processes to recover yttrium. • Recovery of yttrium from primary sources. • Recovery of yttrium from e-waste and other types of waste. - Abstract: Yttrium is important rare earths (REs) used in numerous fields, mainly in the phosphor powders for low-energy lighting. The uses of these elements, especially for high-tech products are increased in recent years and combined with the scarcity of the resources and the environmental impact of the technologies to extract them from ores make the recycling waste, that contain Y and other RE, a priority. The present review summarized themore » main hydrometallurgical technologies to extract Y from ores, contaminated solutions, WEEE and generic wastes. Before to discuss the works about the treatment of wastes, the processes to retrieval Y from ores are discussed, since the processes are similar and derived from those already developed for the extraction from primary sources. Particular attention was given to the recovery of Y from WEEE because the recycle of them is important not only for economical point of view, considering its value, but also for environmental impact that this could be generated if not properly disposal.« less

Metals Recovery from Artificial Ore in Case of Printed Circuit Boards, Using Plasmatron Plasma Reactor

PubMed Central

Szałatkiewicz, Jakub

2016-01-01

This paper presents the investigation of metals production form artificial ore, which consists of printed circuit board (PCB) waste, processed in plasmatron plasma reactor. A test setup was designed and built that enabled research of plasma processing of PCB waste of more than 700 kg/day scale. The designed plasma process is presented and discussed. The process in tests consumed 2 kWh/kg of processed waste. Investigation of the process products is presented with their elemental analyses of metals and slag. The average recovery of metals in presented experiments is 76%. Metals recovered include: Ag, Au, Pd, Cu, Sn, Pb, and others. The chosen process parameters are presented: energy consumption, throughput, process temperatures, and air consumption. Presented technology allows processing of variable and hard-to-process printed circuit board waste that can reach up to 100% of the input mass. PMID:28773804

Metals Recovery from Artificial Ore in Case of Printed Circuit Boards, Using Plasmatron Plasma Reactor.

PubMed

Szałatkiewicz, Jakub

2016-08-10

This paper presents the investigation of metals production form artificial ore, which consists of printed circuit board (PCB) waste, processed in plasmatron plasma reactor. A test setup was designed and built that enabled research of plasma processing of PCB waste of more than 700 kg/day scale. The designed plasma process is presented and discussed. The process in tests consumed 2 kWh/kg of processed waste. Investigation of the process products is presented with their elemental analyses of metals and slag. The average recovery of metals in presented experiments is 76%. Metals recovered include: Ag, Au, Pd, Cu, Sn, Pb, and others. The chosen process parameters are presented: energy consumption, throughput, process temperatures, and air consumption. Presented technology allows processing of variable and hard-to-process printed circuit board waste that can reach up to 100% of the input mass.

Evaluation and development of integrated technology of rare metal concentrate production in high-level ore processing at Zashikhinsk deposit

NASA Astrophysics Data System (ADS)

Khokhulya, MS; Mukhina, TN; Ivanova, V. A.; Mitrofanova, G. V.; Fomin, A. V.; Sokolov, VD

2017-02-01

The authors discuss material constitution of columbite ore sample and recommend optimized pretreatment modes to obtain ball milling products at the maximum dissociation of ore minerals in aggregates. A concentration technology is proposed, with division of material into two flows -0.315 mm and -0.2 mm in sizes, generated in the milling and screening cycles and subjected to gravity-magnetic and magnetic-gravity treatment, respectively. It is shown that the technology ensures production of both tantalum-niobium and zircon concentrates. It has become possible to additionally recover rare metal components Nb2O5 and ZrO2 from tailings through flotation.

Modeling the formation of porphyry-copper ores

USGS Publications Warehouse

Ingebritsen, Steven E.

2012-01-01

Porphyry-copper ore systems, the source of much of the world's copper and molybdenum, form when metal-bearing fluids are expelled from shallow, degassing magmas. On page 1613 of this issue, Weis et al. (1) demonstrate that self-organizing processes focus metal deposition. Specifically, their simulation studies indicate that ores develop as consequences of dynamic variations in rock permeability driven by injection of volatile species from rising magmas. Scenarios with a static permeability structure could not reproduce key field observations, whereas dynamic permeability responses to magmatic-fluid injection localized a metal-precipitation front where enrichment by a factor of 103 could be achieved [for an overview of their numerical-simulation model CSMP++, see (2)].

Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

NASA Astrophysics Data System (ADS)

Saramak, Daniel; Krawczykowska, Aldona; Młynarczykowska, Anna

2014-10-01

This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

The physical hydrogeology of ore deposits

USGS Publications Warehouse

Ingebritsen, Steven E.; Appold, M.S.

2012-01-01

Hydrothermal ore deposits represent a convergence of fluid flow, thermal energy, and solute flux that is hydrogeologically unusual. From the hydrogeologic perspective, hydrothermal ore deposition represents a complex coupled-flow problem—sufficiently complex that physically rigorous description of the coupled thermal (T), hydraulic (H), mechanical (M), and chemical (C) processes (THMC modeling) continues to challenge our computational ability. Though research into these coupled behaviors has found only a limited subset to be quantitatively tractable, it has yielded valuable insights into the workings of hydrothermal systems in a wide range of geologic environments including sedimentary, metamorphic, and magmatic. Examples of these insights include the quantification of likely driving mechanisms, rates and paths of fluid flow, ore-mineral precipitation mechanisms, longevity of hydrothermal systems, mechanisms by which hydrothermal fluids acquire their temperature and composition, and the controlling influence of permeability and other rock properties on hydrothermal fluid behavior. In this communication we review some of the fundamental theory needed to characterize the physical hydrogeology of hydrothermal systems and discuss how this theory has been applied in studies of Mississippi Valley-type, tabular uranium, porphyry, epithermal, and mid-ocean ridge ore-forming systems. A key limitation in the computational state-of-the-art is the inability to describe fluid flow and transport fully in the many ore systems that show evidence of repeated shear or tensional failure with associated dynamic variations in permeability. However, we discuss global-scale compilations that suggest some numerical constraints on both mean and dynamically enhanced crustal permeability. Principles of physical hydrogeology can be powerful tools for investigating hydrothermal ore formation and are becoming increasingly accessible with ongoing advances in modeling software.

Iron-ore resources of the United States including Alaska and Puerto Rico, 1955

USGS Publications Warehouse

Carr, Martha S.; Dutton, Carl E.

1959-01-01

The importance of iron ore, the basic raw material of steel, as a fundamental mineral, resource is shown by the fact that about 100 million long tons of steel is used annually in the economy of the United States, as compared with a combined total of about 5 million long tons of copper, lead, zinc, and aluminum. Satisfying this annual demand for steel requires about 110 million tons of iron ore and 70 million tons of scrap iron and steel. The average annual consumption of iron ore in the United States from 1951 to 1955, inclusive, was about 110 million long tons, which is about twice the annual average from 1900 to 1930. Production of iron ore in the United States in this 5-year period averaged approximately 100 million long tons annually, divided by regions as follows (in percent): Lake Superior, 84.1; southeastern, 6.7; western, 6.7; northeastern, 1.4; and central and gulf, 1.1. Mining of iron ore began in the American Colonies about 1619, and for 225 years it was limited to eastern United States where fuel and markets were readily available. Production of iron ore from the Lake Superior region began in 1846; the region became the leading domestic source by 1890, and the Mesabi range in Minnesota has been the world's most productive area since 1896. Proximity of raw materials, water transportation, and markets has resulted in centralization of the country's iron and steel industry in the lower Great Lakes area. Increased imports of iron ore being delivered to eastern United States as well as demands for steel in nearby markets have given impetus to expansion in the steel-making capacity in this area. The four chief iron-ore minerals - hematite, liminite, magnetite, and siderite - are widely distributed but only locally form deposits of sufficient tonnage and grade to be commercially valuable at the present time. The iron content of these minerals, of which hematite is the most important, ranges from 48 percent in siderite to 72 percent in magnetite, but as these minerals are associated with other rock-forming minerals, the iron content of marketable ore has a lower range from 30 to 67 percent.Chemical constituents other than iron also are important in determining the marketability of iron ore. Although some iron ores can be used in the blast furnace as mined, others must first be improved either chemically by reduction of undesirable constituents, or physically by aggregation. Phosphorus and sulfur particularly are common deleterious elements; excessive silica is also undesirable but within certain limits can be controlled by additional flux. Lime and magnesia are beneficial in specified amounts because of their fluxing qualities, and a small amount of alumina improves the fluidity of slag. Manganese is especially desirable as a deoxidizing and desulfurizing agent. Titanium, chromium, and nickel must also be considered in the use of ore containing these elements.The principal iron-ore deposits in the United States have been formed by three processes. Hematite-bearing bedded deposits such as those at Birmingham, Ala., are marine sedimentary rocks which, except for weathering along the outcrop, have remained practically unaltered since deposition. Deposits of the Lake Superior region, also in sedimentary strata, originally had a slightly lower iron content than those at-Birmingham, but ore bodies of hematite and limonite were formed by removal of other constituents in solution after deposition of the beds, with a relative increase of iron content in the material remaining. Limestone adjacent to igneous intrusions has been replaced by magnetite deposits at Cornwall, Pa., and by hematite-magnetite deposits near Cedar City, Utah. Magnetite deposits in New Jersey and in the Adirondack Mountains of New York are generally believed to have been formed by replacement of grains of other minerals in metamorphic rocks. Iron-ore resources are made up of reserves of iron ore, material usable under existing economic and technologic conditions; and potential ore, material likely to become usable under more favorable conditions. The tonnage and grade of material of combined reserves and potential ore in each of the deposits known or believed to contain at least 200,000 long tons of iron-ore resources are tabulated in this report, and numerous sources of additional information are given in a selected bibliography. The total domestic iron-ore resources are estimated at approximately 75,000 million long tons of crude ore. About 10,000 million tons of the resources is reserves of crude ore that will probably yield 5,500 million tons of concentrates and direct-shipping ore. About 65,000 million tons is potential ore and may yield 25,000 million tons of concentrates and some direct-shipping ore.

Nitrile/Buna N Material Failure Assessment for an O-Ring used on the Gaseous Hydrogen Flow Control Valve (FCV) of the Space Shuttle Main Engine

NASA Technical Reports Server (NTRS)

Wingard, Doug

2006-01-01

After the rollout of Space Shuttle Discovery in April 2005 in preparation for return-to-flight, there was a failure of the Orbiter (OV-103) helium signature leak test in the gaseous hydrogen (GH2) system. Leakage was attributed to the Flow Control Valve (FCV) in Main Engine 3. The FCV determined to be the source of the leak for OV-103 is designated as LV-58. The nitrile/Buna N rubber O-ring seal was removed from LV-58, and failure analysis indicated radial cracks providing leak paths in one quadrant. Cracks were eventually found in 6 of 9 FCV O-rings among the three Shuttle Orbiters, though none were as severe as those for LV-58, OV-103. Testing by EM10 at MSFC on all 9 FCV O- rings included: laser dimensional, Shore A hardness and properties from a dynamic mechanical analyzer (DMA) and an Instron tensile machine. The following test data was obtained on the cracked quadrant of the LV-58, OV-103 O-ring: (1) the estimated compression set was only 9.5%, compared to none for the rest of the O-ring; (2) Shore A hardness for the O.D. was higher by almost 4 durometer points than for the rest of the O-ring; and (3) DMA data showed that the storage/elastic modulus E was almost 25% lower than for the rest of the O-ring. Of the 8 FCV O-rings tested on an Instron, 4 yielded tensile strengths that were below the MIL spec requirement of 1350 psi-a likely influence of rubber cracking. Comparisons were made between values of modulus determined by DNA (elastic) and Instron (Young s). Each nitrile/Buna N O-ring used in the FCV conforms to the MIL-P-25732C specification. A number of such O-rings taken from shelf storage at MSFC and Kennedy Space Center (KSC) were used to generate a reference curve of DMA glass transition temperature (Tg) vs. shelf storage time ranging from 8 to 26 years. A similar reference curve of TGA onset temperature (of rubber weight loss) vs. shelf storage time was also generated. The DMA and TGA data for the used FCV O-rings were compared to the reference curves. Correlations were also made between the DMA modulus (at 22 C) and Shore A hardness for all 9 of the FCV O-rings used among the three Shuttle Orbiters. The radial cracking in the FCV O-rings was determined to be due to ozone attack, as nitrile/Buna N rubber is susceptible to such attack. Nitrile/Buna N material under MIL-P25732C should be used in a hydraulic fluid environment to help protect it from cracking. However, the FCV O-rings were used in an air only environment. The FCV design has as much as a 9-mil gap that allows the O.D. of the O-ring to be directly exposed to ozone, pressurized air and some elevated temperatures, accelerating the weathering process that leads to O-ring cracking. Space Shuttle flights will likely not continue past 2010. Therefore, Shuttle management decided to continue using the nitrile/Buna N material for the FCVs, but have each O-ring replaced after 3 years to minimize any chances for crack initiation.

Shale-oil-recovery systems incorporating ore beneficiation. Final report.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Weiss, M.A.; Klumpar, I.V.; Peterson, C.R.

This study analyzed the recovery of oil from oil shale by use of proposed systems which incorporate beneficiation of the shale ore (that is concentration of the kerogen before the oil-recovery step). The objective was to identify systems which could be more attractive than conventional surface retorting of ore. No experimental work was carried out. The systems analyzed consisted of beneficiation methods which could increase kerogen concentrations by at least four-fold. Potentially attractive low-enrichment methods such as density separation were not examined. The technical alternatives considered were bounded by the secondary crusher as input and raw shale oil as output.more » A sequence of ball milling, froth flotation, and retorting concentrate is not attractive for Western shales compared to conventional ore retorting; transporting the concentrate to another location for retorting reduces air emissions in the ore region but cost reduction is questionable. The high capital and energy cost s results largely from the ball milling step which is very inefficient. Major improvements in comminution seem achievable through research and such improvements, plus confirmation of other assumptions, could make high-enrichment beneficiation competitive with conventional processing. 27 figures, 23 tables.« less

Effect of rare earth Ce on the far infrared radiation property of iron ore tailings ceramics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Liu, Jie; Institute of Power Source and Ecomaterials Science, Hebei University of Technology, Tianjin 300130; Meng, Junping, E-mail: srlj158@sina.com

2015-06-15

Highlights: • Detailed process proposed for preparation of iron ore tailings ceramics. • Replace natural minerals with iron ore tailings as raw materials for preparing functional ceramics. • Impact mechanism of Ce on far infrared ceramics, as well as its optimum addition amounts can be obtained. • Propose a new perspective on considering the mechanism of far infrared radiation. - Abstract: A kind of far infrared radiation ceramics was prepared by using iron ore tailings, CaCO{sub 3} and SiO{sub 2} as main raw materials, and Ce as additive. The result of Fourier transform infrared spectroscopy showed that the sample exhibitsmore » excellent radiation value of 0.914 when doping 7 wt.% Ce. Ce{sup 4+} dissolved into iron diopside and formed interstitial solid solution with it sintered at 1150 °C. The oxidation of Fe{sup 2+} to Fe{sup 3+} caused by Ce{sup 4+} led to a decrease of crystallite sizes and enhancement of Mg–O and Fe–O vibration in iron diopside, which consequently improved the far infrared radiation properties of iron ore tailings ceramics.« less

The influence of geomorphology on the role of women at artisanal and small-scale mine sites

USGS Publications Warehouse

Malpeli, Katherine C.; Chirico, Peter G.

2013-01-01

The geologic and geomorphic expressions of a mineral deposit determine its location, size, and accessibility, characteristics which in turn greatly influence the success of artisans mining the deposit. Despite this critical information, which can be garnered through studying the surficial physical expression of a deposit, the geologic and geomorphic sciences have been largely overlooked in artisanal mining-related research. This study demonstrates that a correlation exists between the roles of female miners at artisanal diamond and gold mining sites in western and central Africa and the physical expression of the deposits. Typically, women perform ore processing and ancillary roles at mine sites. On occasion, however, women participate in the extraction process itself. Women were found to participate in the extraction of ore only when a deposit had a thin overburden layer, thus rendering the mineralized ore more accessible. When deposits required a significant degree of manual labour to access the ore due to thick overburden layers, women were typically relegated to other roles. The identification of this link encourages the establishment of an alternative research avenue in which the physical and social sciences merge to better inform policymakers, so that the most appropriate artisanal mining assistance programs can be developed and implemented.

Potential Aquifer Vulnerability in Regions Down-Gradient from ...

EPA Pesticide Factsheets

Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are instrumental in leaching uranium from source rocks and transporting it in low concentrations to a chemical redox interface where it is deposited in an ore zone typically containing the uranium minerals uraninite, pitchblende, and/or coffinite; various iron sulfides; native selenium; clays; and calcite. In situ recovery (ISR) of these uranium ores is a process of contacting the uranium mineral deposit with leaching (lixiviant) fluids via injection of the lixiviant into wells drilled into the subsurface aquifer that hosts uranium ore, while other extraction wells pump the dissolved uranium after dissolution of the uranium minerals. Environmental concerns during and after ISR include water quality impacts from: 1) potential excursions of leaching solutions away from the injection zone into down-dip, underlying, or overlying aquifers; 2) potential migration of uranium and its decay products (e.g., Ra, Rn, Pb); and, 3) potential migration of redox-sensitive trace metals (e.g., Fe, Mn, Mo, Se, V), metalloids (e.g., As), and anions (e.g., sulfate). This review describes the geochemical processes that control roll-front uranium transport and fate in groundwater systems, identifies potential aquifer vulnerabilities to ISR operations, identifies

Effects of the addition of municipal solid waste incineration fly ash on the behavior of polychlorinated dibenzo-p-dioxins and furans in the iron ore sintering process.

PubMed

Min, Yi; Liu, Chengjun; Shi, Peiyang; Qin, Chongda; Feng, Yutao; Liu, Baichen

2018-04-11

Raw materials were co-sintered with municipal solid waste incineration (MSWI) fly ash through iron ore sintering to promote the safe treatment and utilization of MSWI fly ash. To assess the feasibility of this co-sintering method, in this study, the effects of the addition of MSWI fly ash on the formation and emission of polychlorinated dibenzo-p-dioxins and furans (PCDD/Fs) were estimated via iron ore sintering pot experiments. During co-sintering, most of the PCDD/Fs in the added MSWI fly ash were decomposed and transformed into PCDD/Fs associated with iron sintering, and the concentrations of lower- and mid-chlorinated congeners increased. As there was a sufficient chlorine source and the sintering bed permeability was decreased by the addition of MSWI fly ash, the PCDD/F concentration in the exhaust gas increased. The mass emission of PCDD/Fs decreased; however, the emission of toxic PCDD/Fs increased beyond the total emissions from the independent MSW incineration and iron ore sintering processes due to the transformation of PCDD/F congeners. The co-sintering may be an important solution after technological improvements in the flue gas cleaning system and PCDD/F formation inhibition procedures. Copyright © 2018. Published by Elsevier Ltd.

Regularities of spatial association of major endogenous uranium deposits and kimberlitic dykes in the uranium ore regions of the Ukrainian Shield

NASA Astrophysics Data System (ADS)

Kalashnyk, Anna

2015-04-01

During exploration works we discovered the spatial association and proximity time formation of kimberlite dykes (ages are 1,815 and 1,900 Ga for phlogopite) and major industrial uranium deposits in carbonate-sodium metasomatites (age of the main uranium ore of an albititic formation is 1,85-1,70 Ga according to U-Pb method) in Kirovogradsky, Krivorozhsky and Alekseevsko-Lysogorskiy uranium ore regions of the Ukrainian Shield (UkrSh) [1]. In kimberlites of Kirovogradsky ore region uranium content reaches 18-20 g/t. Carbon dioxide is a major component in the formation of hydrothermal uranium deposits and the formation of the sodium in the process of generating the spectrum of alkaline ultrabasic magmas in the range from picritic to kimberlite and this is the connection between these disparate geochemical processes. For industrial uranium deposits in carbonate-sodium metasomatitics of the Kirovogradsky and Krivorozhsky uranium ore regions are characteristic of uranyl carbonate introduction of uranium, which causes correlation between CO2 content and U in range of "poor - ordinary - rich" uranium ore. In productive areas of uranium-ore fields of the Kirovogradsky ore region for phlogopite-carbonate veinlets of uranium ore albitites deep δ13C values (from -7.9 to -6.9o/oo) are characteristic. Isotope-geochemical investigation of albitites from Novokonstantynovskoe, Dokuchaevskoe, Partyzanskoe uranium deposits allowed obtaining direct evidence of the involvement of mantle material during formation of uranium albitites in Kirovogradsky ore region [2]. Petrological characteristics of kimberlites from uranium ore regions of the UkrSh (presence of nodules of dunite and harzburgite garnet in kimberlites, diamonds of peridotite paragenesis, chemical composition of indicator minerals of kimberlite, in particular Gruzskoy areas pyropes (Cr2O3 = 6,1-7,1%, MgO = 19,33-20,01%, CaO = 4,14-4,38 %, the content of knorringite component of most grains > 50mol%), chromites (Cr2O3 = 45,32-62,17%, MgO = 7,3-12,5%) allow us to estimate the depth of generation of kimberlite magmas more than 170-200 km. Ilmenites show two groups according to MgO, Cr2O3 and TiO2 content. Reconstructions of the mantle sections show also two intervals of pressures divided at 4.5 GPa, the upper part is highly metasomatized This high degree metasomatism is determined for almost all mantle columns. It is suggested that large-scale of uranium-bearing mantle fluids may be associated with the ancient degasation during the subduction which is highly enriched in U component . Analysis of the reasons for the marked association kimberlitic dykes and major industrial uranium deposits in carbonate-sodium metasomatic in the UkrSh led to the conclusion that hydrothermal uranium deposits are confined to the supply mantle fluid systems of mantle fault zones exercising brings sodium carbonate solutions enriched uranium from mantle sources. References: 1. Kalashnik A.A. New prognostic-evaluation criteria in technology prognosis of forming industrial endogenous uranium deposits of the Ukrainian Shield, 2014. Scientific proceedings of UkrSGRI, № 2, p. 27-54 (in Russian) 2. Stepanjuk L.M., Bondarenko S.V., Somka V.O. and other, 2012. Source of uranium and uranium-bearing sodium albitites for example of Dokuchaievskogo field of the Ingulsky megablock of the UkrSh: Abstracts of scientific conference "Theoretical issues and research practice metasomatic rocks and ores" (Kyiv, 14-16 March 2012), IGMOF, p.78-80. (in Ukrainian)

VOLATILE CHLORIDE PROCESS FOR THE RECOVERY OF METAL VALUES

DOEpatents

Hanley, W.R.

1959-01-01

A process is presented for recovering uranium, iron, and aluminum from centain shale type ores which contain uranium in minute quantities. The ore is heated wiih a chlorinating agent. such as chlorine, to form a volatilized stream of metal chlorides. The chloride stream is then passed through granular alumina which preferentially absorbs the volatile uranium chloride and from which the uranium may later be recovered. The remaining volatilized chlorides, chiefly those of iron and aluminum, are further treated to recover chlorine gas for recycle, and to recover ferric oxide and aluminum oxide as valuable by-products.

Atmosphere Issues in Detection of Explosives and Organic Residues

DTIC Science & Technology

2009-01-01

sensitivity “false posi Fi ores are then c diagonal of th o itself. How null. Distanc fact that differ 8. Resultant mat valuating the perator Chara ly...consid 3. EXPE used in order ver Operator Ch l_figure.asp?img e A represen .0. This mean re of merit (th extreme case, ositive or a fa lutions, and si... detector gate width is 50 μsec and is delayed 40 ns after the laser, while the nanosecond spectra has a gate width of 10 μsec and is delayed 50 ns after

Titanium minerals of placer deposits as a source for new materials

NASA Astrophysics Data System (ADS)

Kotova, Olga; Ponaryadov, Alexey

2015-04-01

Heavy mineral deposits are a source of the economic important element titanium, which is contained in ilmenite and leucoxene. The mineral composition of placer titanium ore and localization pattern of ore minerals determine their processing and enriching technologies. New data on the mineralogy of titanium ores from modern coastal-marine placer in Stradbroke Island, Eastern Australia, and Pizhma paleoplacer in Middle Timan, Russia, and materials on their basis are presented. The samples were studied by the following methods: optical-mineralogical (stereomicroscope MBS-10, polarizing microscope POLAM L-311), semiquantitative x-ray phase analysis (x-ray difractometer X'Pert PRO MPD). Besides microprobe (VEGA 3 TESCAN) and x-ray fluorescent analysis (XRF-1800 Shimadzu) were used. By the mineralogical composition ores of the both deposits are complex: enriched by valuable minerals. Apart from main ore concentrates it is possible to obtain accompanying nonmetallic products. This will increase the efficiency of deposit exploitation. Ilmenite dominates in ore sands of Stradbroke Island, and leucoxene dominates in the ores of the Pizhma titanium deposit. Australian ilmenite and its altered varieties are mainly characterized by a very high MnO content (from 5.24 to 11.08 %). The irregular distribution of iron oxides, titanium and manganese in the altered ilmenite was shown in the paper. E.g., in the areas of substitution of ilmenite by pseudorutile the concentrations of the given elements are greatly various due to various ratios of basic components in each grain. Their ratios are equal in the area of rutile evolution. Moreover, the high content of gold, diamonds and also rare earth elements (REE) and rare metals (their forms are not determined) were studied. We found native copper on the surface of minerals composing titanium-bearing sandstones of the Pizhma placer. According to the technological features of rocks (density and magnetic) studied placers are close. The obtained results of physical studies, mineral composition features, morphostructural characteristics and degree of alteration of titanium minerals from the placers specify a high potential of physical methods of processing (gravitational and magnetic separation, flotation) and possible application of combined methods of processing. Production of pigment titanium dioxide for further production of titanium white, paper, plastics etc is the usual application area of titanium concentrates. Titanium dioxide of high chemical purity is used to produce optically transparent glass, fiber optics, electronics (iPad), piezoceramics, in medical and food industry. We designed photocatalysts based on leucoxene from Pizhma placer. The results showed that the photocatalysts based on rutile, synthesized from leucoxene from Pizhma deposit, can be applied to decay phenols in water.

Sulfur, carbon, hydrogen, and oxygen isotope geochemistry of the Idaho cobalt belt

USGS Publications Warehouse

Johnson, Craig A.; Bookstrom, Arthur A.; Slack, John F.

2012-01-01

Cobalt-copper ± gold deposits of the Idaho cobalt belt, including the deposits of the Blackbird district, have been analyzed for their sulfur, carbon, hydrogen, and oxygen isotope compositions to improve the understanding of ore formation. Previous genetic hypotheses have ranged widely, linking the ores to the sedimentary or diagenetic history of the host Mesoproterozoic sedimentary rocks, to Mesoproterozoic or Cretaceous magmatism, or to metamorphic shearing. The δ34S values are nearly uniform throughout the Blackbird dis- trict, with a mean value for cobaltite (CoAsS, the main cobalt mineral) of 8.0 ± 0.4‰ (n = 19). The data suggest that (1) sulfur was derived at least partly from sedimentary sources, (2) redox reactions involving sulfur were probably unimportant for ore deposition, and (3) the sulfur was probably transported to sites of ore for- mation as H2S. Hydrogen and oxygen isotope compositions of the ore-forming fluid, which are calculated from analyses of biotite-rich wall rocks and tourmaline, do not uniquely identify the source of the fluid; plausible sources include formation waters, metamorphic waters, and mixtures of magmatic and isotopically heavy meteoric waters. The calculated compositions are a poor match for the modified seawaters that form vol- canogenic massive sulfide (VMS) deposits. Carbon and oxygen isotope compositions of siderite, a mineral that is widespread, although sparse, at Blackbird, suggest formation from mixtures of sedimentary organic carbon and magmatic-metamorphic carbon. The isotopic compositions of calcite in alkaline dike rocks of uncertain age are consistent with a magmatic origin. Several lines of evidence suggest that siderite postdated the emplacement of cobalt and copper, so its significance for the ore-forming event is uncertain. From the stable isotope perspective, the mineral deposits of the Idaho cobalt belt contrast with typical VMS and sedimentary exhalative deposits. They show characteristics of deposit types that form in deeper environments and could be related to metamorphic processes or magmatic processes, although the isotopic evidence for magmatic components is relatively weak.

Novel Binders and Methods for Agglomeration of Ore

DOE Office of Scientific and Technical Information (OSTI.GOV)

S. K. Kawatra; T. C. Eisele; K. A. Lewandowski

2006-09-30

Heap leaching is one of the methods being used to recover metal from low grade ore deposits. The main problem faced during heap leaching is the migration of fine grained particles through the heap, forming impermeable beds which result in poor solution flow. The poor solution flow leads to less contact between the leach solution and the ore, resulting in low recovery rates. Agglomeration of ore into coarse, porous masses prevents fine particles from migrating and clogging the spaces and channels between the larger ore particles. Currently, there is one facility in the United States which uses agglomeration. This operationmore » agglomerates their ore using leach solution (raffinate), but is still experiencing undesirable metal recovery from the heaps due to agglomerate breakdown. The use of a binder, in addition to the leach solution, during agglomeration would help to produce stronger agglomerates that did not break down during processing. However, there are no known binders that will work satisfactorily in the acidic environment of a heap, at a reasonable cost. As a result, operators of many facilities see a large loss of process efficiency due to their inability to take advantage of agglomeration. Increasing copper recovery in heap leaching by the use of binders and agglomeration would result in a significant decrease in the amount of energy consumed. Assuming that 70% of all the leaching heaps would convert to using agglomeration technology, as much as 1.64*10{sup 12} BTU per year would be able to be saved if a 25% increase in copper recovery was experienced, which is equivalent to saving approximately 18% of the energy currently being used in leaching heaps. For every week a leach cycle was decreased, a savings of as much as 1.23*10{sup 11} BTU per week would result. This project has identified several acid-resistant binders and agglomeration procedures. These binders and experimental procedures will be able to be used for use in improving the energy efficiency of heap leaching.« less

Hydrologic Investigations Concerning Lead Mining Issues in Southeastern Missouri

USGS Publications Warehouse

Kleeschulte, Michael J.

2008-01-01

Good stewardship of our Nation's natural resources demands that the extraction of exploitable, minable ore deposits be conducted in harmony with the protection of the environment, a dilemma faced by many land and water management agencies in the Nation's mining areas. As ore is mined, milled, and sent to the smelter, it leaves footprints where it has been in the form of residual trace metals. Often these footprints become remnants that can be detrimental to other natural resources. This emphasizes the importance of understanding the earth's complex physical and biological processes and their interactions at increasingly smaller scales because subtle changes in one component can substantially affect others. Understanding these changes and resulting effects requires an integrated, multidisciplinary scientific approach. As ore reserves are depleted in one area, additional exploitable deposits are required to replace them, and at times these new deposits are discovered in previously unmined areas. Informed decisions concerning resource management in these new, proposed mining areas require an understanding of the potential consequences of the planned mining actions. This understanding is usually based on knowledge that has been accumulated from studying previously mined areas with similar geohydrologic and biologic conditions. If the two areas experience similar mining practices, the information should be transferable. Lead and zinc mining along the Viburnum Trend Subdistrict of southeastern Missouri has occurred for more than 40 years. Additional potentially exploitable deposits have been discovered 30 miles to the south, within the Mark Twain National Forest. It is anticipated that the observation of current (2008) geohydrologic conditions in the Viburnum Trend can provide insight to land managers that will help reasonably anticipate the potential mining effects should additional mining occur in the exploration area. The purpose of this report is to present a compilation of previously unpublished information that was collected as part of a larger multidisciplinary study of lead mining issues in southeastern Missouri. The report resulted from the application of a multidisciplinary approach to investigate current hydrologic and biologic conditions in streams of the Viburnum Trend and the exploration area in the Mark Twain National Forest.

Ore Reserve Estimation of Saprolite Nickel Using Inverse Distance Method in PIT Block 3A Banggai Area Central Sulawesi

NASA Astrophysics Data System (ADS)

Khaidir Noor, Muhammad

2018-03-01

Reserve estimation is one of important work in evaluating a mining project. It is estimation of the quality and quantity of the presence of minerals have economic value. Reserve calculation method plays an important role in determining the efficiency in commercial exploration of a deposit. This study was intended to calculate ore reserves contained in the study area especially Pit Block 3A. Nickel ore reserve was estimated by using detailed exploration data, processing by using Surpac 6.2 by Inverse Distance Weight: Squared Power estimation method. Ore estimation result obtained from 30 drilling data was 76453.5 ton of Saprolite with density of 1.5 ton/m3 and COG (Cut Off Grade) Ni ≥ 1.6 %, while overburden data was 112,570.8 tons with waste rock density of 1.2 ton/m3 . Striping Ratio (SR) was 1.47 : 1 smaller than Stripping Ratio ( SR ) were set of 1.60 : 1.

The control of H2S in biogas using iron ores as in situ desulfurizers during anaerobic digestion process.

PubMed

Zhou, Qiying; Jiang, Xia; Li, Xi; Jiang, Wenju

2016-09-01

In this study, five kinds of iron ores, limonite, hematite, manganese ore, magnetite and lava rock, were used as the in situ desulfurizers in the anaerobic digestion reactors to investigate their effects on controlling H2S in biogas. The results show that the addition of the five iron ores could significantly control the content of H2S in biogas, with the best performance for limonite. As limonite dosages increase (10-60 g/L), the contents of H2S in biogas were evidently decreased in the digesters with different initial sulfate concentrations (0-1000 mg/L). After the anaerobic digestion, the removed sulfur was mostly deposited on the surface of limonite. A possible mechanism of H2S control in biogas by limonite was proposed preliminarily, including adsorption, FeS precipitation, and Fe (III) oxidation. The results demonstrated that limonite was a promising in situ desulfurizer for controlling H2S in biogas with low cost and high efficiency.

Effect of moisture content on the flowability of crushed ores

NASA Astrophysics Data System (ADS)

Cabrejos, Francisco

2017-06-01

In many mining and industrial processes where large quantities of non-degrading bulk materials such as crushed ores are handled, silos, hoppers, stockpiles and chutes are widely used because they are economical and reliable (if properly designed and operated). However, they are not free of trouble and may experience flow problems such as arching, ratholing, erratic flow, limited storage capacity, limited discharge flow rate, caking, segregation and/or flooding. Moisture content and fine particles significantly affect the flowability of most ores, increasing their cohesive strength and turning them more prone to these problems. The purpose of this article is to highlight a proven, scientific method that can be utilized to ensure reliable storage, flow and discharge of bulk solids in these equipment based on Jenike's flow-of-solids theory and laboratory testing. Knowledge of the flow properties of the material handled provides a design basis to ensure mass flow, avoid arching and prevent the formation of "ratholes". The effect of an increase in water content of the ore is discussed with experimental results.

Recovery of Iron from Hematite-Rich Diasporic-Type Bauxite Ore

NASA Astrophysics Data System (ADS)

Jiang, Tao; Li, Zhuoxuan; Yang, Lin; Li, Guanghui; Zhang, Yuanbo; Zeng, Jinghua

A technique has been proposed for recovering iron from hematite-rich diasporic-type bauxite ore in this study. Direct reduction roasting followed by low intensity wet magnetic separation process was carried out. The parameters including reduction temperature and time, sodium salts, grinding conditions and magnetic field intensity for separation of iron were determined. The optimum process parameters as follows: roasting temperature of 1050 °C, time of 60 min, sodium salts involving sodium sulfate, borax, sodium carbonate with dosages of 10 wt%, 2 wt%, 35 wt% respectively, and magnetic field intensity of 1000 Gs with fineness of pulp reached 92.75% passing -0.074mm. Under the optimal conditions, an iron concentrate containing 88.17% total iron grade and iron recovery of 92.51% was obtained, 4.55% total iron grade in tailings. This novel technique provide a potential route for utilizing hematiterich diasporic bauxite ore, recovering iron resource firstly, and extracting alumina from magnetic separation tailings further.

UNDERGROUND URANIUM MINING ON COLORADO PLATEAU

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dare, W.L.

1958-10-31

The size and continuity of the Chinie ore bodies in the Big Indian district, Utah, have permitted mine operators in plan a more integrated development and mining system using larger and more specialized equipment. Thick ore and firm backs at the south end of the district than permitted room and pillar mining, using large drill jumbos send diesel-powered haulage equipment. The Gismo loader and draw-chute system has proved efficient. Driving the haulage- way below the stope level is an advantage when pillars are recovered. To the north, thinner ore with weaker backs favor retreat systems and smaller equipment. Here, themore » ore bodies are delineated by a grid system of drifts, send the ore recovered by panel, longwall, or similar mining methods, retreating toward the principal entry. Labor productivity ranges from 8 to 21 tons per man-shift, send direct mining send development costs, excluding initial development, ranges from 75 to 51 per ton. A unique system of mine development is in the Temple Mountain district, Utah, where the shallow Chinie deposits are mined through 36- inch diameter calyx drill holes. Using small diesel-powered ore buggies and bucket hoisting, ore in produced from the two largest mines at a rate of 4.1 tons per man-shift, at a direci cost of 15 a ton. Ambrosia Lake deposits range from 5 to 80 feet thick and occur from 350 to 1,000 feet below the surface. These mines are in development stages. Open, retreat, and top-slice sloping is planned. Adequate ventilation is essential in uranium mining since sufficient air must be coursed through the workings to maintain airborne radioactive concentration at tolerance levels send dilute exhaust gases where diesel-powered equipment is used. Uranium miners have found that radiometric scannning is a quick and efficient method for checking ths grade of the ore produced and in process of development. (auth)« less

Geochemical and mineralogical composition of bog iron ore as a resource for prehistoric iron production - A case study of the Widawa catchment area in Eastern Silesia, Poland

NASA Astrophysics Data System (ADS)

Thelemann, Michael; Bebermeier, Wiebke; Hoelzmann, Philipp

2016-04-01

Spreading from the Near East in the declining Bronze Age from the 2nd millennium BCE onwards, the technique of iron smelting reached Eastern Silesia, Poland, in approximately the 2nd century BCE (pre-Roman Iron Age). At this time the region of the Widawa catchment area was inhabited by the Przeworsk culture. While the older moraine landscape of the study area lacks ores from geological rock formations, bog iron ores were relatively widespread and, due to their comparatively easy accessibility, were commonly exploited for early iron production. In this poster the mineralogical and elemental composition of local bog iron ore deposits and iron slag finds, as a by-product of the smelting process, are investigated. The crystalline mineralogical composition of local bog iron ores is dominated by quartz (SiO2) and goethite (α FeO(OH)), in contrast to slag samples in which fayalite (Fe2SiO4), wüstite (FeO) and quartz, with traces of goethite, represent the main minerals. Ores and slags are both characterized by notable hematite (Fe2O3), magnetite (Fe3O4) and maghemite (γ-Fe2O3) contents. Analyzed bog iron ore samples show iron contents of up to 64.9 mass% Fe2O3 (45.4 mass% Fe), whereas the iron contents of bloomery slags vary between 48.7 and 72.0 mass% FeO (37.9 and 56.0 mass% Fe). A principal component analysis of the element contents, which were quantified by portable energy-dispersive X-ray fluorescence spectrometry (p-ED-XRF), indicates local variations in the elemental composition. Our results show that bog iron ores are relatively widely distributed with spatially varying iron contents along the Widawa floodplain but present-day formation conditions (e.g. different ground-water levels) are negatively affected by modern land-use practices, such as agriculture and melioration measures.

Biomining with bacteriophage: selectivity of displayed peptides for naturally occurring sphalerite and chalcopyrite.

PubMed

Curtis, Susan B; Hewitt, Jeff; Macgillivray, Ross T A; Dunbar, W Scott

2009-02-01

During mineral processing, concentrates of sulfide minerals of economic interest are formed by froth flotation of fine ore particles. The method works well but recovery and selectivity can be poor for ores with complex mineralogy. There is considerable interest in methods that improve the selectivity of this process while avoiding the high costs of using flotation chemicals. Here we show the first application of phage biotechnology to the processing of economically important minerals in ore slurries. A random heptapeptide library was screened for peptide sequences that bind selectively to the minerals sphalerite (ZnS) and chalcopyrite (CuFeS2). After several rounds of enrichment, cloned phage containing the surface peptide loops KPLLMGS and QPKGPKQ bound specifically to sphalerite. Phage containing the peptide loop TPTTYKV bound to both sphalerite and chalcopyrite. By using an enzyme-linked immunosorbant assay (ELISA), the phage was characterized as strong binders compared to wild-type phage. Specificity of binding was confirmed by immunochemical visualization of phage bound to mineral particles but not to silica (a waste mineral) or pyrite. The current study focused primarily on the isolation of ZnS-specific phage that could be utilized in the separation of sphalerite from silica. At mining sites where sphalerite and chalcopyrite are not found together in natural ores, the separation of sphalerite from silica would be an appropriate enrichment step. At mining sites where sphalerite and chalcopyrite do occur together, more specific phage would be required. This bacteriophage has the potential to be used in a more selective method of mineral separation and to be the basis for advanced methods of mineral processing.

Lake Superior, Duluth, MN

NASA Technical Reports Server (NTRS)

1973-01-01

This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo.

Fast counting electronics for neutron coincidence counting

DOEpatents

Swansen, James E.

1987-01-01

An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a .sup.3 He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output ) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

Fast counting electronics for neutron coincidence counting

DOEpatents

Swansen, J.E.

1985-03-05

An amplifier-discriminator is tailored to output a very short pulse upon an above-threshold input from a detector which may be a /sup 3/He detector. The short pulse output is stretched and energizes a light emitting diode (LED) to provide a visual output of operation and pulse detection. The short pulse is further fed to a digital section for processing and possible ORing with other like generated pulses. Finally, the output (or ORed output) is fed to a derandomizing buffer which converts the rapidly and randomly occurring pulses into synchronized and periodically spaced-apart pulses for the accurate counting thereof. Provision is also made for the internal and external disabling of each individual channel of amplifier-discriminators in an ORed plurality of same.

Lunar vertical-shaft mining system

NASA Technical Reports Server (NTRS)

Introne, Steven D. (Editor); Krause, Roy; Williams, Erik; Baskette, Keith; Martich, Frederick; Weaver, Brad; Meve, Jeff; Alexander, Kyle; Dailey, Ron; White, Matt

1994-01-01

This report proposes a method that will allow lunar vertical-shaft mining. Lunar mining allows the exploitation of mineral resources imbedded within the surface. The proposed lunar vertical-shaft mining system is comprised of five subsystems: structure, materials handling, drilling, mining, and planning. The structure provides support for the exploration and mining equipment in the lunar environment. The materials handling subsystem moves mined material outside the structure and mining and drilling equipment inside the structure. The drilling process bores into the surface for the purpose of collecting soil samples, inserting transducer probes, or locating ore deposits. Once the ore deposits are discovered and pinpointed, mining operations bring the ore to the surface. The final subsystem is planning, which involves the construction of the mining structure.

Study of the Dry Processing of Uranium Ores; ETUDE DES TRAITEMENTS DE MINERAIS D'URANIUM PAR VOIE SECHE

DOE Office of Scientific and Technical Information (OSTI.GOV)

Guillet, H.

1959-02-01

A description is given of direct fluorination of preconcentrated uranium ores in order to obtain the hexafluoride. After normal sulfuric acid treatment of the ore to eliminate silica, the uranium is precipitated by lime to obtain either impure calcium uranate of medium grade, or containing around 10% of uranium. This concentrate is dried in an inert atmosphere and then treated with a current of elementary fluorine. The uranium hexafluoride formed is condensed at the outlet of the reaction vessel and may be used either for reduction to tetrafluoride and the subsequent manufacture of uranium metal or as the initial productmore » in a diffusion plant. (auth)« less

Photosynthetically mediated Zn removal from the water column in High Ore Creek, Montana

USGS Publications Warehouse

Morris, Jeffrey M.; Meyer, Joseph S.

2006-01-01

We collected cobbles covered in biofilm from High Ore Creek, Montana, placed them in 12 transparent PVC plastic chambers, and exposed the chambers to four treatments: Sunlight, Sunlight-occluded, DCMU (photosynthesis inhibited), and Formalin. Total aqueous zinc (Zn) concentrations in the Sunlight treatment decreased during the 4-h experiment and were significantly lower (P ≤ 0.05) than in the other three treatments, in which the total aqueous Zn concentrations did not decrease significantly. Therefore, we believe photosynthesis in the biofilm played a role in causing total aqueous Zn concentrations in the Sunlight treatment to decrease, and we believe a similar process contributes to diel Zn cycling in High Ore Creek and some other metals-contaminated streams.

The Effect of Initial Irrigation Conditions on Heap Leaching Efficiency

NASA Astrophysics Data System (ADS)

Briseño Arellano, A. D.; Milczarek, M.; Yao, M.; Brusseau, M. L. L.

2017-12-01

Heap leaching is an unsaturated flow metal recovery process, in which mined ore is irrigated with a lixiviant to dissolve metal contained in the ore. The metal is then extracted from solution. Large scale operations involve stacking ore to depths of 6 to 18 meters on pads that may be hundreds of hectares in area. Heterogeneities within the stacked ore can lead to uneven wetting and the formation of preferential flow pathways, which reduces solution contact and lowers metal recovery. Furthermore, mineral dissolution can cause alteration of the porous media structure and loss of ore permeability. Many mine operators believe that slow initial irrigation rates help minimize permeability loss and increase metal recovery rates. However, this phenomenon has not been studied in detail. Experiments were conducted to investigate the effect of varying initial irrigation rates on leach ore stability. These were conducted with large columns (1.5 m high, 0.5 m in diameter) packed with crushed ore samples that are known to have permeability constraints. The columns were highly instrumented to assess potential changes in material properties both spatially and temporally. Water content was measured with three different methods: capacitance soil moisture sensors placed at 20-cm intervals; a neutron probe to periodically log every 30 cm from four different directions; and electrical resistivity sensors to create a 2-dimensional tomography profile of water content over time. Tensiometers were paired with the soil moisture sensors to measure matric suction and characterize moisture retention characteristics. A non-reactive tracer was used to characterize advective-dispersive transport under unsaturated conditions. A dye solution was introduced at the end of each experiment to map preferential pathways. Continuous monitoring of settling at the surface assisted in measuring consolidation and loss in permeability.

Contrasting hydrological processes of meteoric water incursion during magmatic-hydrothermal ore deposition: An oxygen isotope study by ion microprobe

NASA Astrophysics Data System (ADS)

Fekete, Szandra; Weis, Philipp; Driesner, Thomas; Bouvier, Anne-Sophie; Baumgartner, Lukas; Heinrich, Christoph A.

2016-10-01

Meteoric water convection has long been recognized as an efficient means to cool magmatic intrusions in the Earth's upper crust. This interplay between magmatic and hydrothermal activity thus exerts a primary control on the structure and evolution of volcanic, geothermal and ore-forming systems. Incursion of meteoric water into magmatic-hydrothermal systems has been linked to tin ore deposition in granitic plutons. In contrast, evidence from porphyry copper ore deposits suggests that crystallizing subvolcanic magma bodies are only affected by meteoric water incursion in peripheral zones and during late post-ore stages. We apply high-resolution secondary ion mass spectrometry (SIMS) to analyze oxygen isotope ratios of individual growth zones in vein quartz crystals, imaged by cathodo-luminescence microscopy (SEM-CL). Existing microthermometric information from fluid inclusions enables calculation of the oxygen isotope composition of the fluid from which the quartz precipitated, constraining the relative timing of meteoric water input into these two different settings. Our results confirm that incursion of meteoric water directly contributes to cooling of shallow granitic plutons and plays a key role in concurrent tin mineralization. By contrast, data from two porphyry copper deposits suggest that downward circulating meteoric water is counteracted by up-flowing hot magmatic fluids. Our data show that porphyry copper ore deposition occurs close to a magmatic-meteoric water interface, rather than in a purely magmatic fluid plume, confirming recent hydrological modeling. On a larger scale, the expulsion of magmatic fluids against the meteoric water interface can shield plutons from rapid convective cooling, which may aid the build-up of large magma chambers required for porphyry copper ore formation.

Fluid evolution and ore genesis of the Dalingshang deposit, Dahutang W-Cu ore field, northern Jiangxi Province, South China

NASA Astrophysics Data System (ADS)

Peng, Ning-Jun; Jiang, Shao-Yong; Xiong, Suo-Fei; Pi, Dao-Hui

2018-02-01

The Dalingshang W-Cu deposit is located in the North section of the Dahutang ore field, northern Jiangxi Province, South China. Vein- and breccia-style tungsten-copper mineralization is genetically associated with Mesozoic S-type granitic rocks. Infrared and conventional microthermometric studies of both gangue and ore minerals show that the homogenization temperatures for primary fluid inclusions in wolframite ( 340 °C) are similar to those in scheelite ( 330 °C), but about 40 °C higher than those of apatite ( 300 °C) and generally 70 °C higher than those in coexisting quartz ( 270 °C). Laser Raman analysis identifies CH4 and N2 without CO2 in fluid inclusions in scheelite and coexisting quartz, while fluid inclusions in quartz of the sulfide stage have variable CO2 content. The ore-forming fluids overall are characterized by high- to medium-temperature, low-salinity, CH4, N2, and/or CO2-bearing aqueous fluids. Chalcopyrite, muscovite, and sphalerite are the most abundant solids recognized in fluid inclusions from different ores. The H-O-S-Pb isotope compositions favor a dominantly magmatic origin for ores and fluids, while some depleted δ34S values (- 14.4 to - 0.9‰) of sulfides from the sulfide stage are most likely produced by an increase of oxygen fugacity, possibly caused by inflow of oxidized meteoric waters. The microthermometric data also indicate that a simple cooling process formed early scheelite and wolframite. However, increasing involvement of meteoric waters and fluid mixing may trigger a successive deposition of base metal sulfides. Fluid-rock interaction was critical for scheelite mineralization as indicated by in-situ LA-ICP-MS analysis of trace elements in scheelite.

Physical and chemical controls on ore shoots - insights from 3D modeling of an orogenic gold deposit

NASA Astrophysics Data System (ADS)

Vollgger, S. A.; Tomkins, A. G.; Micklethwaite, S.; Cruden, A. R.; Wilson, C. J. L.

2016-12-01

Many ore deposits have irregular grade distributions with localized elongate and well-mineralized rock volumes commonly referred to as ore shoots. The chemical and physical processes that control ore shoot formation are rarely understood, although transient episodes of elevated permeability are thought to be important within the brittle and brittle-ductile crust, due to faulting and fracturing associated with earthquake-aftershock sequences or earthquake swarms. We present data from an orogenic gold deposit in Australia where the bulk of the gold is contained in abundant fine arsenopyrite crystals associated with a fault-vein network within tight upright folds. The deposit-scale fault network is connected to a deeper network of thrust faults (tens of kilometers long). Using 3D implicit modeling of geochemical data, based on radial basis functions, gold grades and gold-arsenic element ratios were interpolated and related to major faults, vein networks and late intrusions. Additionally, downhole bedding measurements were used to model first order (mine-scale) fold structures. The results show that ore shoot plunges are not parallel with mine-scale or regional fold plunges, and that bedding parallel faults related to flexural slip folding play a pivotal role on ore shoot attitudes. 3D fault slip and dilation tendency analysis indicate that fault reactivation and formation of linking faults are associated with large volumes of high-grade ore. We suggest slip events on the large-scale thrust network allowed mineralizing fluids to rapidly migrate over large distances and become supersaturated in elements such as gold, promoting widespread precipitation and high nucleation densities of arsenopyrite upon fluid-rock interaction at trap sites within the deposit.

Challenges facing the North American iron ore industry

USGS Publications Warehouse

Jorgenson, J.D.

2005-01-01

During the 20th century, the iron ore mining industries of Canada and the United States passed through several periods of transformation. The beginning of the 21st century has seen yet another period of transformation, with the economic failure of a number of steel companies, the acquisition of their facilities by more viable steelmakers, and the consolidation of control within the North American iron ore industry. Changes in Canadian and United States iron ore production and the market control structure involved are analysed. The consolidation of ownership, formation of foreign joint ventures within Nordi America, planned divestitures of upstream activities by steelmakers, and industry changes made to ensure availability of feedstocks will be reviewed. The ttaditional isolation of the Canadian and United States iron ore operations and their strong linkage to downstream steel production will be discussed in the context of a changing global economy. Management-labour conflicts that have taken place and agreements made during 2000 through 2004 will be discussed in the context of the economic environment leading up to these agreements. Cooperative agreements between competing Canadian and United States companies to resolve client needs in processing and blending will be examined. A joint industry-government project designed to use new technology to produce direct reduced iron nuggets of 96 - 98 per cent iron content using non-coking coals will also be assessed. Changes in iron ore transportation methods, ownership and infrastructure will be reviewed for both rail and inland waterway transport between Canadian and United States companies. A brief analysis of social and environmental issues relating to sustainable development of the Canadian-United States iron ore industry will be included.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cayumil, R.; Khanna, R., E-mail: ritakhanna@unsw.edu.au; Ikram-Ul-Haq, M.

Highlights: • Recycling and material recovery from waste printed circuit boards is very complex. • Thermoset polymers, ceramics and metals are present simultaneously in waste PCBs. • Heat treatment of PCBs was carried out at 1150 °C under inert conditions. • Various metallic phases could be segregated out as copper based metallic droplets. • Carbon and ceramics residues can be further recycled in a range of applications. - Abstract: The rapid consumption and obsolescence of electronics have resulted in e-waste being one of the fastest growing waste streams worldwide. Printed circuit boards (PCBs) are among the most complex e-waste, containingmore » significant quantities of hazardous and toxic materials leading to high levels of pollution if landfilled or processed inappropriately. However, PCBs are also an important resource of metals including copper, tin, lead and precious metals; their recycling is appealing especially as the concentration of these metals in PCBs is considerably higher than in their ores. This article is focused on a novel approach to recover copper rich phases from waste PCBs. Crushed PCBs were heat treated at 1150 °C under argon gas flowing at 1 L/min into a horizontal tube furnace. Samples were placed into an alumina crucible and positioned in the cold zone of the furnace for 5 min to avoid thermal shock, and then pushed into the hot zone, with specimens exposed to high temperatures for 10 and 20 min. After treatment, residues were pulled back to the cold zone and kept there for 5 min to avoid thermal cracking and re-oxidation. This process resulted in the generation of a metallic phase in the form of droplets and a carbonaceous residue. The metallic phase was formed of copper-rich red droplets and tin-rich white droplets along with the presence of several precious metals. The carbonaceous residue was found to consist of slag and ∼30% carbon. The process conditions led to the segregation of hazardous lead and tin clusters in the metallic phase. The heat treatment temperature was chosen to be above the melting point of copper; molten copper helped to concentrate metallic constituents and their separation from the carbonaceous residue and the slag. Inert atmosphere prevented the re-oxidation of metals and the loss of carbon in the gaseous fraction. Recycling e-waste is expected to lead to enhanced metal recovery, conserving natural resources and providing an environmentally sustainable solution to the management of waste products.« less

40 CFR 61.52 - Emission standard.

Code of Federal Regulations, 2012 CFR

2012-07-01

... standard. (a) Emissions to the atmosphere from mercury ore processing facilities and mercury cell chlor... atmosphere from sludge incineration plants, sludge drying plants, or a combination of these that process...

40 CFR 61.52 - Emission standard.

Code of Federal Regulations, 2013 CFR

2013-07-01

... standard. (a) Emissions to the atmosphere from mercury ore processing facilities and mercury cell chlor... atmosphere from sludge incineration plants, sludge drying plants, or a combination of these that process...

40 CFR 61.52 - Emission standard.

Code of Federal Regulations, 2014 CFR

2014-07-01

... standard. (a) Emissions to the atmosphere from mercury ore processing facilities and mercury cell chlor... atmosphere from sludge incineration plants, sludge drying plants, or a combination of these that process...

40 CFR 61.52 - Emission standard.

Code of Federal Regulations, 2011 CFR

2011-07-01

... standard. (a) Emissions to the atmosphere from mercury ore processing facilities and mercury cell chlor... atmosphere from sludge incineration plants, sludge drying plants, or a combination of these that process...

Fe-U-PGE-Au-Ag-Cu Deposits of the Udokan-Chiney Region (East Siberia, Russia)

NASA Astrophysics Data System (ADS)

Gongalskiy, B.; Krivolutskaya, N.; Murashov, K.; Nistratov, S.; Gryazev, S.

2012-04-01

Introduction. Cupriferous sandstones-shales and magmatic copper-nickel deposits mark out the western and southern boundaries of the Siberian Craton accordingly. Of special interest are the Paleoproterozoic deposits of the Udokan-Chiney mining district (Gongalskiy, Krivolutskaya, 2008). Copper reserves and resources of this region are estimated at more than 50 Mt. Half of them is concentrated at the unique Udokan Deposit and the second half is distributed among sedimentary (Unkur, Pravoingamakitskoye, Sakinskoye, Krasnoye, Burpala) and magmatic deposits of the Chiney (Rudnoye, Verkhnechineyskoye, Kontaktovoye), Luktur and Maylav massifs. Results. It was established that the ores are characterized by similarity in chemical composition (main, major and rare elements that are Ag, Au, PGE) and mineral assemblages with varying proportions. It is important to emphasize that Fe role in mineralization was previously ignored. Meanwhile the Udokan deposit contains 10 Mt of magnetite metacrystals so as chalcocite ores may contain up to 50% magnetite too. It has been recently found that the Chiney titanomagnetite ores comprise commercially significant uranium and rare-earth metal concentrations (Makaryev et al., 2011). Thus the Udokan-Chiney region comprises Cu, Fe, Ti, V, U, REE, Ag, Au, PGE. These deposits differ from similar objects, the Olympic Dam in particular, by a much smaller content of fluid-bearing minerals. Copper mineralization at the Udokan is represented by chalcocite-bornite ores. They occur as ore beds conformable with sedimentary structures or as cross-cutting veins. The central zones of the former are often brecciated. They are rimmed by fine magnetite, bornite, and chalcocite dissemination. Bornite-chalcopyrite and chalcopyrite-pyrite veins are known at the lower levels of the Udokan ore bed. Such ore compositions are predominant in other ore deposits in sedimentary rocks (Pravoingamakitskoye, Unkur) and have a hydrothermal origin. Silver grades are up to 370 g/t in grab samples (Gongalskiy et al., 2008a). The long-lived Udokan-Chiney ore-magmatic has small areal extent of explosive rocks and breccias (n*10 m) with massive sulfide veins (chalcopyrite, pyrrhotite) which are similar to Sudbury offset dikes. While the same vertical zones at the Rudnoye deposit have been confirmed over 0.5 km downward from the lower contact of the Chiney massif. Conclusions. Multielement and similar mineralogical composition ores of different deposits in the Udokan-Chiney area reflect long evolution of ore processes in very movable block of the crust. Observed combination of magmatic, sedimentary and partially hydrothermal deposits is a result of the telescoping of a wide range of metals into a limited area.

Comparative Effects of Biochar, Slag and Ferrous-Mn Ore on Lead and Cadmium Immobilization in Soil.

PubMed

Mehmood, Sajid; Rizwan, Muhammad; Bashir, Saqib; Ditta, Allah; Aziz, Omar; Yong, Li Zhe; Dai, Zhihua; Akmal, Muhammad; Ahmed, Waqas; Adeel, Muhammad; Imtiaz, Muhammad; Tu, Shuxin

2018-02-01

A variety of remediation approaches have been applied to the heavy metals-contaminated soils, however, the immobilization of metals in co-contaminated soils still not cleared. Therefore, an incubation study was conducted to evaluate the instantaneous effects of different concentrations of biochar (BC), slag (SL) and Fe-Mn ore (FMO) on immobilization of Pb and Cd through the Toxicity Characteristic Leaching Procedure (TCLP) by following the the European Community Bureau of Reference (BCR), CaCl 2 and NH 4 NO 3 . The sequential extraction of BCR showed decrease in acid soluble fractions, while the residual proportions of Pb and Cd were enhanced with increasing concentrations of SL and BC. Addition of BC significantly lowered the extractable fractions of both metals by TCLP, NH 4 NO 3 and CaCl 2 as compared to SL and FMO. Among all amendments, BC incorporation into co-contaminated soil offered promising results for Pb and Cd immobilization. Overall, all amendments showed positive and long-term impact on the reclamation of co-contaminated soil with heavy metals and could deserve advance monitoring studies on a field scale.

Analysis of the plugging of the systems autonomy demonstration project brassboard filters

NASA Technical Reports Server (NTRS)

Clay, John C.

1989-01-01

A fine gray powder was clogging the brassboard filters. The powder appeared to be residue from a galvanic corrosive attack by ammonia of the aluminum and stainless steel components in the system. The corrosion was caused by water and chlorine that had entered into the system and combined with the ammonia. This combination made an electrolyte and a corrosive agent of the ammonia that attacked the metals in the system. The corroded material traveled through the system with the ammonia and clogged the filters. Key conclusions are: the debris collecting in the filters is a by-product of galvanic corrosion; the debris is principally corroded aluminum and stainless from the system; and galvanic corrosion occurred from water and chlorine that entered the system during normal and/or extreme operating and servicing conditions. Key recommendations are: use only one metal in the ammonia system-titanium, aluminum, or stainless steel; make the system as air-tight as possible (replace fittings with welded joints); and replace electron paramagnetic resonance (EPR) O-rings with neoprene O-rings, and do not use freon to clean system components.

[Effect of temperature on the rate of oxidation of pyrrhotite-rich sulfide ore flotation concentrate and the structure of the acidophilic chemolithoautotrophic microbial community].

PubMed

Moshchanetskii, P V; Pivovarova, T A; Belyi, A V; Kondrat'eva, T F

2014-01-01

Oxidation of flotation concentrate of a pyrrhotite-rich sulfide ore by acidophilic chemolithoautotrophic microbial communities at 35, 40, and 45 degrees C was investigated. According to the physicochemical parameters of the liquid phase of the pulp, as well as the results of analysis of the solid residue after biooxidation and cyanidation, the community developed at 40 degrees C exhibited the highest rate of oxidation. The degree of gold recovery at 35, 40, and 45 degrees C was 89.34, 94.59, and 83.25%, respectively. At 40 degrees C, the highest number of microbial cells (6.01 x 10(9) cells/mL) was observed. While temperature had very little effect on the species composition of microbial communities, except for the absence of Leptospirillum ferriphilum at 35 degrees C, the shares of individual species in the communities varied with temperature. Relatively high numbers of Sulfobacillus thermosulfidooxidans, the organism oxidizing iron and elemental sulfur at higher rates than other acidophilic chemolithotrophic species, were observed at 40 degrees C.

Mechanistic study of lead desorption during the leaching process of ion-absorbed rare earths: pH effect and the column experiment

NASA Astrophysics Data System (ADS)

Xue, Q.; Tang, J., Sr.; Chen, H.

2017-12-01

High concentrations of ammonium sulfate, often used in the in-situ mining process, can result in a decrease of pH in the environment and dissolution of rare earth metals. Ammonium sulfate can also cause desorption of toxic heavy metals, leading to environmental and human health implications. In this study, the desorption behavior and fraction changes of lead in the ion-absorbed rare earth ore were studied using batch desorption experiments and column leaching tests. Results from batch desorption experiments showed that the desorption process of lead included fast and slow stages, and followed an Elovich model well. The desorption rate and the proportion of lead content in the solution to the total lead in the soil were observed to increase with a decrease in the initial pH of the ammonium sulfate solution. The lead in soil included an acid extractable fraction, reducible fraction, oxidizable fraction, and a residual fraction, with the predominant fractions being the reducible and acid extractable fractions. 96% of the extractable fraction in soil were desorbed into solution at pH=3.0, and the content of the reducible fraction was observed to initially increase (when pH>4.0) and then decrease (when pH<4.0) with a decrease in pH. Column leaching tests indicated that the content of lead in the different fractions of soil followed the trend of reducible fraction > oxidizable fraction > acid extractable fraction > residual fraction after the simulating leaching mining process. The change in pH was also found to have a larger influence on the acid extractable and reducible fractions than the other two fractions. The proportion of the extractable fraction being leached was ca. 86%, and the reducible fraction was enriched along the migration direction of the leaching liquid. These results suggest that certain lead fractions may desorb again and contaminate the environment via acid rain, which provides significant information for environmental assessment and remediation after mining process.

A high throughput passive dosing format for the Fish Embryo Acute Toxicity test.

PubMed

Vergauwen, Lucia; Schmidt, Stine N; Stinckens, Evelyn; Maho, Walid; Blust, Ronny; Mayer, Philipp; Covaci, Adrian; Knapen, Dries

2015-11-01

High throughput testing according to the Fish Embryo Acute Toxicity (FET) test (OECD Testing Guideline 236) is usually conducted in well plates. In the case of hydrophobic test substances, sorptive and evaporative losses often result in declining and poorly controlled exposure conditions. Therefore, our objective was to improve exposure conditions in FET tests by evaluating a passive dosing format using silicone O-rings in standard 24-well polystyrene plates. We exposed zebrafish embryos to a series of phenanthrene concentrations until 120h post fertilization (hpf), and obtained a linear dilution series. We report effect values for both mortality and sublethal morphological effects based on (1) measured exposure concentrations, (2) (lipid normalized) body residues and (3) chemical activity. The LC50 for 120hpf was 310μg/L, CBR50 (critical body residue) was 2.72mmol/kg fresh wt and La50 (lethal chemical activity) was 0.047. All values were within ranges expected for baseline toxicity. Impaired swim bladder inflation was the most pronounced morphological effect and swimming activity was reduced in all exposure concentrations. Further analysis showed that the effect on swimming activity was not attributed to impaired swim bladder inflation, but rather to baseline toxicity. We conclude that silicone O-rings (1) produce a linear dilution series of phenanthrene in the 120hpf FET test, (2) generate and maintain aqueous concentrations for reliable determination of effect concentrations, and allow for obtaining mechanistic toxicity information, and (3) cause no toxicity, demonstrating its potential as an extension of the FET test when testing hydrophobic chemicals. Copyright © 2015 Elsevier Ltd. All rights reserved.

Continuous Steelmaking Directly from Ore

NASA Astrophysics Data System (ADS)

Warner, Noel A.

2014-12-01

In-line continuous processing of high-grade hematite ore (crushed ore or fines) with a pure hydrogen reductant is assessed. An appraisal is made of the rate controlling mechanisms involved in the reduction of a pure layer of molten wustite being transported by floating on a molten carrier iron carbon-free medium at temperatures just in excess of the iron melting point. Published research clearly indicates that under these conditions the kinetics are principally controlled by molecular gaseous diffusion. Thus, the rate is essentially not influenced by total gas pressure above 1 atmosphere. Accordingly, on safety grounds it is recommended that high pressure should not be used for hydrogen steelmaking in the future, but the operation should be conducted close to atmospheric pressure with low pressure steam encapsulation of the plant items involved. Using hydrogen as the reductant means that sub-surface nucleation of CO bubbles cannot disrupt continuous processing. The operation is then no different to processing a normal liquid phase. The off-gases from the reduction zone of a melt circulation loop are super-clean and only contaminated with iron vapor. Accordingly, the best available technology becomes available for energy conservation without risk of non-fusible solids deposition. The net result is that the energy requirements are expected to be superior to other potential processes.

Geology and Fluorspar Deposits of the Levias-Keystone and Dike-Eaton Areas, Crittenden County, Kentucky

USGS Publications Warehouse

Trace, Robert Denny

1962-01-01

The fault systems of the Levias-Keystone and Dike-Eaton areas, in the Kentucky-Illinois fiuorspar district, are a complex northeastward-trending sys- tem and a simple northwestward-trending system of steeply dipping normal faults, associated in part with a lamprophyre dike. Fluorspar mining started in the area about 1900 and, as of 1945, more than 200,000 tons of crude ore probably has been mined; most of the ore was from the Levias-Keystone area. A small quantity of zinc and lead ore also is present in the Dike-Eaton area. The deposits are localized along faults that displace fiat-lying or low-dipping limestones, sandstones, and shales of the Meramec and Chester series of Missis- sippian age. Movement along most of the faults was principally vertical, with displacement as much as 600 feet. Some horizontal movement occurred along at least one fault. Geologic mapping of the surface and data from underground workings have revealed 13 faults in an area of four-fifths of a square mile. Only a few of these faults are known to contain economically important deposits of fiuorspar. The most abundant vein minerals are calcite and fiuorite with subordinate quantities of sphalerite, galena, barite, and quartz. Some weathering products of sphalerite and galena are present also. The veins are dominantly calcite that contains fiuorite lenses but in places are mainly fiuorite having lesser quantities of calcite. Sphalerite- and galena-bearing deposits are present in the Dike-Eaton area. The ore bodies mainly are the result of fissure filling and replacement of calcite by fiuorite; in addition a small amount of limestone wallrock probably has been replaced. Residual concentrations of high-grade fluorspar in the overburden above faults have yielded some so-called gravel fiuorspar. The position of the veins within the faults may be related to one or more factors such as type of wallrock, change in dip of the fault, and amount of displacement.

Geology of the Wood and East Calhoun mines, Central City District, Gilpin County, Colorado

USGS Publications Warehouse

Drake, Avery Ala

1955-01-01

The Wood-East Calhoun mine area is underlain by complexly folded Precambrian gneiss and pegmatite. The major fold in the area is an anticline that trends about N. 60° E. The Precambrian rocks are intruded by bostonite porphyry dikes of Tertiary age. All the rocks are cut by east- to northeast - trending faults that have been filled by precious metal-sulfide veins which have been worked chiefly for gold. The Wood vein occurs in an east-trending fault; the Calhoun vein occurs in a northeast-trending fault. Much of the uranium production of the Central City district has come from the Wood vein on Quartz Hill. The veins consist chiefly of quartz; pyrite is the chief metallic mineral and chalcopyrite is next in abundance. Sphalerite, galena, tetrahedrite-tennantite, and pitchblende are locally present. Deposition began with alteration-stage quartz and pyrite followed in order by pitchblend, light-yellow pyrite, massive quartz, yellow pyrite, shalerite, comb quartz, chalcopyrite, tetrahedrite-tennantite, galena, chalcopyrite, pyrite, and gray to light-brown fine-grained quartz. The veins of the Central City district are zoned, with quartz-pyrite veins near the center and galena-sphalerite veins on the periphery. The known pitchblende bodies are in the transition between these, but paragenetically, the pitchblende is earlier than all other metallic minerals. A trace element study of the ore indicates an association of zirconium and molybdenum with uranium, of bismuth, antimony, and arsenic with copper, and of cadmium with zinc. The pitchblende and other ore minerals are concentrated in ore shoots. The shoots are in open spaces controlled by the competency of the wall rocks, the presence of a prevailing direction of weakness in the rocks, and changes in strike and dip of the vein. The pitchblende is thought to be a local constituent of the quartz-pyrite ores and to owe its origin to residual solutions from the quartz bostonite magma.

A case–control study of mesothelioma in Minnesota iron ore (taconite) miners

PubMed Central

Lambert, Christine S; Alexander, Bruce H; Ramachandran, Gurumurthy; MacLehose, Richard F; Nelson, Heather H; Ryan, Andrew D; Mandel, Jeffrey H

2018-01-01

Objectives An excess of mesothelioma has been observed in iron ore miners in Northeastern Minnesota. Mining and processing of taconite iron ore generate exposures that include elongate mineral particles (EMPs) of amphibole and non-amphibole origin. We conducted a nested case–control study of mesothelioma in a cohort of 68 737 iron ore miners (haematite and taconite ore miners) to evaluate the association between mesothelioma, employment and EMP exposures from taconite mining. Methods Mesothelioma cases (N=80) were identified through the Minnesota Cancer Surveillance System (MCSS) and death certificates. Four controls of similar age were selected for each case with 315 controls ultimately eligible for inclusion. Mesothelioma risk was evaluated by estimating rate ratios and 95% CIs with conditional logistic regression in relation to duration of taconite industry employment and cumulative EMP exposure [(EMP/cc)×years], defined by the National Institute for Occupational Safety and Health (NIOSH) 7400 method. Models were adjusted for employment in haematite mining and potential exposure to commercial asbestos products used in the industry. Results All mesothelioma cases were male and 57 of the cases had work experience in the taconite industry. Mesothelioma was associated with the number of years employed in the taconite industry (RR=1.03, 95% CI 1.00 to 1.06) and cumulative EMP exposure (RR=1.10, 95% CI 0.97 to –1.24). No association was observed with employment in haematite mining. Conclusions These results support an association between mesothelioma and employment duration and possibly EMP exposure in taconite mining and processing. The type of EMP was not determined. The potential role of commercial asbestos cannot be entirely ruled out. PMID:26655961

Ultrafine particles derived from mineral processing: A case study of the Pb-Zn sulfide ore with emphasis on lead-bearing colloids.

PubMed

Mikhlin, Yuri; Vorobyev, Sergey; Romanchenko, Alexander; Karasev, Sergey; Karacharov, Anton; Zharkov, Sergey

2016-03-01

Although mining and mineral processing industry is a vast source of heavy metal pollutants, the formation and behavior of micrometer- and nanometer-sized particles and their aqueous colloids entered the environment from the technological media has received insufficient attention to date. Here, the yield and characteristics of ultrafine mineral entities produced by routine grinding of the Pb-Zn sulfide ore (Gorevskoe ore deposit, Russia) were studied using laser diffraction analysis (LDA), dynamic light scattering (DLS) and zeta potential measurement, microscopy, X-ray photoelectron spectroscopy, with most attention given to toxic lead species. It was revealed, in particular, that the fraction of particles less that 1 μm in the ground ore typical reaches 0.4 vol. %. The aquatic particles in supernatants were micrometer size aggregates with increased content of zinc, sulfur, calcium as compared with the bulk ore concentrations. The hydrodynamic diameter of the colloidal species decreased with time, with their zeta potentials remaining about -12 mV. The colloids produced from galena were composed of 20-50 nm PbS nanoparticles associated with lead sulfate and thiosulfate, while the surface oxidation products at precipitated galena were largely lead oxyhydroxides. The size and zeta potential of the lead-bearing colloids decreased with time down to about 100 nm and from -15 mV to -30 mV, respectively. And, conversely, lead sulfide nanoparticles were mobilized before the aggregates during redispersion of the precipitates in fresh portions of water. The potential environmental impact of the metal-bearing colloids, which is due to the large-scale production and relative stability, is discussed. Copyright © 2015 Elsevier Ltd. All rights reserved.

A case-control study of mesothelioma in Minnesota iron ore (taconite) miners.

PubMed

Lambert, Christine S; Alexander, Bruce H; Ramachandran, Gurumurthy; MacLehose, Richard F; Nelson, Heather H; Ryan, Andrew D; Mandel, Jeffrey H

2016-02-01

An excess of mesothelioma has been observed in iron ore miners in Northeastern Minnesota. Mining and processing of taconite iron ore generate exposures that include elongate mineral particles (EMPs) of amphibole and non-amphibole origin. We conducted a nested case-control study of mesothelioma in a cohort of 68,737 iron ore miners (haematite and taconite ore miners) to evaluate the association between mesothelioma, employment and EMP exposures from taconite mining. Mesothelioma cases (N=80) were identified through the Minnesota Cancer Surveillance System (MCSS) and death certificates. Four controls of similar age were selected for each case with 315 controls ultimately eligible for inclusion. Mesothelioma risk was evaluated by estimating rate ratios and 95% CIs with conditional logistic regression in relation to duration of taconite industry employment and cumulative EMP exposure [(EMP/cc)×years], defined by the National Institute for Occupational Safety and Health (NIOSH) 7400 method. Models were adjusted for employment in haematite mining and potential exposure to commercial asbestos products used in the industry. All mesothelioma cases were male and 57 of the cases had work experience in the taconite industry. Mesothelioma was associated with the number of years employed in the taconite industry (RR=1.03, 95% CI 1.00 to 1.06) and cumulative EMP exposure (RR=1.10, 95% CI 0.97 to -1.24). No association was observed with employment in haematite mining. These results support an association between mesothelioma and employment duration and possibly EMP exposure in taconite mining and processing. The type of EMP was not determined. The potential role of commercial asbestos cannot be entirely ruled out. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://www.bmj.com/company/products-services/rights-and-licensing/

Lunar oxygen and metal for use in near-earth space - Magma electrolysis

NASA Technical Reports Server (NTRS)

Colson, Russell O.; Haskin, Larry A.

1990-01-01

The unique conditions on the moon, such as vacuum, absence of many reagents common on the earth, and presence of very nontraditional 'ores', suggest that a unique and nontraditional process for extracting materials from the ores may prove the most practical. An investigation has begun into unfluxed silicate electrolysis as a method for extracting oxygen, Fe, and Si from lunar regolith. The advantages of the process include simplicity of concept, absence of need to supply reagents from the earth, and low power and mass requirements for the processing plant. Disadvantages include the need for uninterrupted high temperature and the highly corrosive nature of the high-temperature silicate melts, which has made identifying suitable electrode and container materials difficult.

Development and application of biotechnologies in the metal mining industry.

PubMed

Johnson, D Barrie

2013-11-01

Metal mining faces a number of significant economic and environmental challenges in the twenty-first century for which established and emerging biotechnologies may, at least in part, provide the answers. Bioprocessing of mineral ores and concentrates is already used in variously engineered formats to extract base (e.g., copper, cobalt, and nickel) and precious (gold and silver) metals in mines throughout the world, though it remains a niche technology. However, current projections of an increasing future need to use low-grade primary metal ores, to reprocess mine wastes, and to develop in situ leaching technologies to extract metals from deep-buried ore bodies, all of which are economically more amenable to bioprocessing than conventional approaches (e.g., pyrometallurgy), would suggest that biomining will become more extensively utilized in the future. Recent research has also shown that bioleaching could be used to process a far wider range of metal ores (e.g., oxidized ores) than has previously been the case. Biotechnologies are also being developed to control mine-related pollution, including securing mine wastes (rocks and tailings) by using "ecological engineering" approaches, and also to remediate and recover metals from waste waters, such as acid mine drainage. This article reviews the current status of biotechnologies within the mining sector and considers how these may be developed and applied in future years.

Seaching for a Silver Lining: Using Pb Isotopes to Constrain the Source of Argentiferous Galena at La Isabela

NASA Astrophysics Data System (ADS)

Thibodeau, A. M.; Killick, D. J.; Ruiz, J.; Chesley, J. T.; Baker, M.

2005-12-01

This study investigates the smelting and refining of argentiferous galena at La Isabela, Dominican Republic (1493-1498), the town founded by Columbus on his second voyage to the Americas. Archaeologists recovered approximately 100 kilograms of galena and 200 kilograms of metallurgical slag near the remains of a crude furnace unearthed at the site (Deagan and Cruxent 2002). The purpose of this study was to determine if these remains are evidence that members of Columbus's fleet prospected for silver during his second expedition. Samples of ore and slag were examined as metallographic polished sections, and petrographic thin sections by optical and scanning electron microscopes. The composition of the ore and slag allows us to infer these ores were processed in a two-stage procedure to produce silver metal and a lead silicate slag. Electron microprobe analysis of galena indicates highly variable but low Ag content (50 ppm), which may account for the fact some of the ore was left unprocessed. Lead isotope analysis by multi-collector ICP-MS indicates that the galena likely came from a single source and was not mined within the Caribbean. Instead, the isotopic signature of these ores is consistent with an Old World source, possibly in the Linares-La Carolina Pb-Zn vein field of southwestern Spain.

Lithologic and structural controls of limestone-hosted Pb-Zn-Ag mineralization in Chihuahua, Mexico

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lofquist, D.J.; Ruiz, J.

1985-01-01

The state of Chihuahua contains some of the most important limestone-hosted ore deposits in Mexico. The best example are Santa Eulalia and Naica which together have produced 53 million tons or ore averaging 7.7% Pb, 6.4% Zn, and 280 g/ton Ag. These deposits occur as mantos and chimneys often accompanied by calc-silicates. Among the most critical questions in this type of deposit is the control that the limestone-host exerts on the mineralizing process. Here the authors present the first detailed data on the stratigraphic and lithologic character of the limestone-hosts at Naica and Santa Eulalia. All ore at Naica andmore » Santa Eulalia is hosted by micrites, biomicrites and biosparites indicative of generally quiet marine deposition. The authors work suggests that the western edge of the this trough might be a low angle, east dipping ramp which extends below the Sierra Madre Occidental. The primary permeability of the limestone that hosts Naica and Santa Eulalia is in the micro to nanodarcy range. The effective permeability has been augmented by 3 or 4 stages of micro-fracturing. Most of the ore is controlled by these fractures and by felsic dikes, which in cases are mostly endoskarn. Stylolites also appear to have exerted a control on the mineralizing process. Numerous instances of alteration and recrystallization confined to one side of a horizontal stylolite have been noted. At Santa Eulalia, horizontal stylolites have controlled the emplacement of massive sulfide mantos, suggesting that the mineralizing process was rather passive.« less

An Overview of Process Monitoring Related to the Production of Uranium Ore Concentrate

DOE Office of Scientific and Technical Information (OSTI.GOV)

McGinnis, Brent

2014-04-01

Uranium ore concentrate (UOC) in various chemical forms, is a high-value commodity in the commercial nuclear market, is a potential target for illicit acquisition, by both State and non-State actors. With the global expansion of uranium production capacity, control of UOC is emerging as a potentially weak link in the nuclear supply chain. Its protection, control and management thus pose a key challenge for the international community, including States, regulatory authorities and industry. This report evaluates current process monitoring practice and makes recommendations for utilization of existing or new techniques for managing the inventory and tracking this material.

A report on the medieval mining and ore processing complex: Zilan valley, Van, Turkey.

NASA Astrophysics Data System (ADS)

Ateş, Yusuf; Kılıη, Sinan

Literature has records of the use of obsidian that shows the existence of a knowledge base on raw material resources around Lake Van extending to very ancient times. Against this background, very little information can be obtained from literature about accurate location of historical mining activities in the region today. An ancient mining and processing complex, located northwest of the city of Van (Turkey) has been discovered by chance in 2007. The purpose of this article is to describe this historical mining area. The site contains mining structures such as shafts and galleries, and heaves of stone chips indicating some ore enrichment activities taking place there. The XRD and chemical analyses show the samples taken from the ore vein are rich in Manganese (Mn) and Barium (Ba), and it is concluded that the Zilan Valley Mining and Processing Complex was for Pyrolusite (MnO2), Barium or both. The site is being described for the first time in the literature and offers an opportunity to fulfill the gap in literature regarding mining history. The discovery and the description of the site would also have implications in a wide multidisciplinary scientific community, including metallurgy, archeology, and world heritage.

The Contributions Regarding the Use of Microwave to Obtain Modeling Gypsum for Phonic-Absorbent Construction and Orthopedic Materials

NASA Astrophysics Data System (ADS)

Pop, P. A.; Ungur, P. A.; Caraban, A.; Marcu, F.

2009-11-01

The paper has presented some experiments realized at "Congips" Co. Oradea and University of Oradea, regarding of increase machining efficiency and quality for modeling gypsum plaster by using of microwave energy to gypsum ore roast. The elaboration process of microwave energy for modeling gypsum plaster has done on electromagnetic waves properties and specific properties for dielectric materials. Microwaves are radiations of electromagnetic waveform nature, determine by pulsations of electrical-E) and magnetically-H components of electromagnetic wave in interdependence with Maxwell equations. The gypsum ore is calcium sulphate dehydrate (CaSO4ṡ2H2O) using at modeling gypsum plaster fabrication, which is calcium sulphate hemihydrate (CaSO4ṡ1/2H2O), that has behavior of dielectric with losses. The gypsum ore getting in microwave field, in conditions of predictable pressure and temperature has transformed in modeling gypsum plaster, by quick lost of a part from crystallization water. The processing time is very short, which due to a great productivity and machining efficiency, finally of low process cost. All of these recommend continuing the research at pilot station level.

Biocatalytic and chemical leaching of a low-grade nickel laterite ore

NASA Astrophysics Data System (ADS)

Ciftci, Hasan; Atik, Suleyman; Gurbuz, Fatma

2018-04-01

Nickel and cobalt recovery from a low-grade nickel laterite ore, supplied from Çaldağ deposit (Manisa, Turkey) were investigated by bio and chemical leaching processes. The fungus, Aspergillus niger was used for biocatalytic leaching experiments. The effects of parameters (solid ratio and sucrose concentration) on the biocatalytic leaching of the ore were initially tested in flasks to obtain the optimum conditions for the A. niger. Then chemical leaching was applied as a comparison to bioleaching, using organic acids (citric, oxalic, acetic and gluconic acids) as well as a mixture of acids. According the results, the maximum dissolution yield of nickel, cobalt and iron were detected respectively as 95.3%, 74.3% and 50.0% by biocatalytic processes which containing 25% (w/v) sucrose and 1% (w/v) solids. The increase in the solid ratio adversely influenced the biocatalytic activity of A. niger. Finally, further tests in reactors (v = 1 and 10 L) were performed using the optimum conditions from the flask tests. The difference in metals recovery between biocatalytic and chemical leaching was significantly important. Bioleaching produced higher Ni and Co extractions (34.3-75.6%) than chemical process.

Four magnetite generations in the Precambrian Varena Iron Ore deposit, SE Lithuania, as a result of rock-fluid interactions

NASA Astrophysics Data System (ADS)

Skridlaite, Grazina; Prusinskiene, Sabina; Siliauskas, Laurynas

2017-04-01

Iron ores in Precambrian crystalline basement of the Varena area, SE Lithuania, were discovered during the detail geological-geophysical exploration in 1982-1992. They are covered with 210-500 m thick sediments. The Varena Iron Ore deposit (VIOD) may yield from 71 to 219.6 million tons of iron ore according to different economic evaluations (Marfin, 1996). They were assumed to be of metasomatic and hydrothermal origin, however several other hypotheses explaining the VIOZ origin, e.g. as a layered mafic or carbonatite intrusions were also suggested. Magnetites of the VIOD were thoroughly investigated by the Cameca SX100 microprobe at the Warsaw University and by the Quanta 250 Energy Dispersive Spectroscopy (EDS) at the Nature Research Centre in Vilnius, Lithuania. Four generations of magnetite were distinguished in the studied serpentine-magnetite ores (D8 drilling) and were compared with the earlier studied and reference magnetites. The earliest, spinel inclusion-rich magnetite cores (Mag-1) have the highest trace element contents (in wt%): Si (0.032), Al (0.167-0.248), Mg (0.340-0.405), Ti (0.215-0.254), V (0.090-0.138) etc. They might have formed during an early metamorphism and/or related skarn formation. Voluminous second magnetite (Mag-2) replacing olivine, pyroxenes, spinel and other skarn minerals at c. 540o C (Magnetite-Ilmenite geothermometer) has much lower trace element abundances, probably washed out by hydrothermal fluids. The latest magnetites (Mag-3 and Mag-4) overgrow the earlier ones and occur near or within the sulfide veins (Mag-4). As was observed from microtextures, the Mag-3 and Mag-4 have originated from the late thermal reworking by dissolution-reprecipitation processes. To imply an origin of the studied magnetites, they were compared to the earlier studied magmatic-metamorphic (1058 drilling), presumably skarn (982 drilling) magnetites from the studied area and plotted in the major magnetite ore type fields according to Dupuis and Beaudoin (2011). They have similar trace element abundances as skarn magnetites, e.g. are in general Ti-poor. The Mag-1 is more than twice richer in Mg than the porphyry and Kiruna type iron ores. A slight enrichment in Al, Ti and V because of spinel and ilmenite inclusions may have caused the earliest Mag-1 to resemble the porphyry type ores, while the secondary Mag-2 has Al, Ca and Mn contents as low as the Kiruna type ores. Thus, we can consider that fluid-rock interactions have strongly affected chemical compositions of the studied magnetites. Even though there are no precise age constructions for the metamorphic, metasomatic and hydrothermal iron ore formation process, they likely started later than 1.80 Ga (metamorphism of the host rocks; Bogdanova et al., 2015) and lasted until c. 1.50 Ga, when the rocks were intruded by the within-plate AMCG magmatic bodies. Bogdanova, S., Gorbatschev, R., Skridlaite, G., Soesoo, A., Taran, L., Kurlovich, D., 2015. Precambrian Research, 259, 5-33. Dupuis, C., Beaudoin, G., 2011. Mineral Deposita 46, 319-335. Marfinas, S., 1996. Report on the results of the evaluation of the Varena Iron Ore deposit, 2nd book, Vilnius.

Abandoned Mine Lands

EPA Pesticide Factsheets

Abandoned Mine Lands are those lands, waters, and surrounding watersheds where extraction, beneficiation, or processing of ores and minerals (excluding coal) has occurred. These lands also include areas where mining or processing activity is inactive.

PROCESS FOR THE RECOVERY OF URANIUM FROM PHOSPHATIC ORE

DOEpatents

Long, R.L.

1959-04-14

A proccss is described for the recovery of uranium from phosphatic products derived from phosphatic ores. It has been discovered that certain alkyl phosphatic, derivatives can be employed in a direct solvent extraction operation to recover uranium from solid products, such as superphosphates, without first dissolving such solids. The organic extractants found suitable include alkyl derivatives of phosphoric, pyrophosphoric, phosof the derivative contains from 4 to 7 carbon atoms. A diluent such as kerosene is also used.

Minerals Price Increases and Volatility: Causes and Consequences

DTIC Science & Technology

2008-10-03

goods , used to make final products, rose 8%. Both rates are triple those at this time [in 2007].8 A 2008 report for Lehman Brothers, a New York-based...products, which are the most widely used intermediate goods produced from iron ore (all ferrous scrap was originally processed from iron ore). Some...prices, even though demand for final goods using steel products was not nearly so robust. The clearest example is in sheet steel, which, in the first

Liquid-Oxygen-Compatible Cement for Gaskets

NASA Technical Reports Server (NTRS)

Elmore, N. L.; Neale, B. C.

1984-01-01

Fluorelastomer and metal bonded reliably by new procedure. To cure fluoroelastomer cement, metal plate/gasket assembly placed in vacuum bag evacuated to minimum vacuum of 27 inches (69 cm) of mercury. Vacuum maintained throughout heating process and until assembly returns to ambient room temperature. Used to seal gaskets and O-rings or used to splice layers of elastomer to form non-standard sized O-rings. Another possible use is to apply protective, liquid-oxygen-compatible coating to metal parts.

The isotopic composition of ore lead of the Creede mining district and vicinity, San Juan Mountains, Colorado: Text of a talk presented at the San Juan Mountains symposium to honor Thomas A. Steven; Rocky Mountain Section meeting of the Geological Society of America, May 2, 1987, Boulder, Colorado

USGS Publications Warehouse

Foley, N.K.; Barton, P.B.; Bethke, P.M.; Doe, B.R.

1988-01-01

Recent work allows us to extend the results of Doe et al. and to consider alternative processes to explain the widespread homogeneity and radiogenic nature of the ore lead: 1) David Matty (pers. commun., 1986) has shown that some minor volcanic units in the area have unusually radiogneic lead values; magmas comparable in composition to the units are a possible, though improbable, source of the ore lead. 2) The uniformity of the isotopic values of galenas may have resulted from homogenization during an extensive potassium-metasomatic event that predated the ores; this possibility is being tested in an on-going study of feldspars from metasomatized and unmetasomatized rocks. 3) Recent regional studies suggest the possibility of a prevolcanic, NNW-trending graben system filled by clastic sediments derived from the Precambrian basement, a process that would have an homogenizing effect on the lead isotopes. This interpretation implies importation, deep within the Creede hydrologic system, of fluids from remote sources. These alternatives show that the Pbisotope systematics may have a profound impact on the interpretation of the Creede hydrothermal system, and that further study is warranted.

Comprehensive Utilization of Iron and Phosphorus from High-Phosphorus Refractory Iron Ore

NASA Astrophysics Data System (ADS)

Sun, Yongsheng; Zhang, Qi; Han, Yuexin; Gao, Peng; Li, Guofeng

2018-02-01

An innovative process of coal-based reduction followed by magnetic separation and dephosphorization was developed to simultaneously recover iron and phosphorus from one typical high-phosphorus refractory iron ore. The experimental results showed that the iron minerals in iron ore were reduced to metallic iron during the coal-based reduction and the phosphorus was enriched in the metallic iron phase. The CaO-SiO2-FeO-Al2O3 slag system was used in the dephosphorization of metallic iron. A hot metal of 99.17% Fe and 0.10% P was produced with Fe recovery of 84.41%. Meanwhile, a dephosphorization slag of 5.72% P was obtained with P recovery of 67.23%. The contents of impurities in hot metal were very low, and it could be used as feedstock for steelmaking after a secondary refining. Phosphorus in the dephosphorization slag mainly existed in the form of a 5CaO·P2O5·SiO2 solid solution where the P2O5 content is 13.10%. At a slag particle size of 20.7 μm (90% passing), 94.54% of the P2O5 could be solubilized in citric acid, indicating the slag met the feedstock requirements in phosphate fertilizer production. Consequently, the proposed process achieved simultaneous Fe and P recovery, paving the way to comprehensive utilization of high-phosphorus refractory iron ore.

Development of a standard reference material for Cr(vi) in contaminated soil

USGS Publications Warehouse

Nagourney, S.J.; Wilson, S.A.; Buckley, B.; Kingston, H.M.S.; Yang, S.-Y.; Long, S.E.

2008-01-01

Over the last several decades, considerable contamination by hexavalent chromium has resulted from the land disposal of Chromite Ore Processing Residue (COPR). COPR contains a number of hexavalent chromium-bearing compounds that were produced in high temperature industrial processes. Concern over the carcinogenic potential of this chromium species, and its environmental mobility, has resulted in efforts to remediate these waste sites. To provide support to analytical measurements of hexavalent chromium, a candidate National Institute of Standards and Technology (NIST) Standard Reference Material?? (SRM 2701), having a hexavalent chromium content of approximately 500 mg kg -1, has been developed using material collected from a waste site in Hudson County, New Jersey, USA. The collection, processing, preparation and preliminary physico-chemical characterization of the material are discussed. A two-phase multi-laboratory testing study was carried out to provide data on material homogeneity and to assess the stability of the material over the duration of the study. The study was designed to incorporate several United States Environmental Protection Agency (USEPA) determinative methods for hexavalent chromium, including Method 6800 which is based on speciated isotope dilution mass spectrometry (SIDMS), an approach which can account for chromium species inter-conversion during the extraction and measurement sequence. This journal is ?? The Royal Society of Chemistry 2008.

Molybdenum isotope fractionation during acid leaching of a granitic uranium ore

NASA Astrophysics Data System (ADS)

Migeon, Valérie; Bourdon, Bernard; Pili, Eric; Fitoussi, Caroline

2018-06-01

As an attempt to prevent illicit trafficking of nuclear materials, it is critical to identify the origin and transformation of uranium materials from the nuclear fuel cycle based on chemical and isotope tracers. The potential of molybdenum (Mo) isotopes as tracers is considered in this study. We focused on leaching, the first industrial process used to release uranium from ores, which is also known to extract Mo depending on chemical conditions. Batch experiments were performed in the laboratory with pH ranging from 0.3 to 5.5 in sulfuric acid. In order to span a large range in uranium and molybdenum yields, oxidizers such as nitric acid, hydrogen peroxide and manganese dioxide were also added. An enrichment in heavy Mo isotopes is produced in the solution during leaching of a granitic uranium ore, when Mo recovery is not quantitative. At least two Mo reservoirs were identified in the ore: ∼40% as Mo oxides soluble in water or sulfuric acid, and ∼40% of Mo hosted in sulfides soluble in nitric acid or hydrogen peroxide. At pH > 1.8, adsorption and/or precipitation processes induce a decrease in Mo yields with time correlated with large Mo isotope fractionations. Quantitative models were used to evaluate the relative importance of the processes involved in Mo isotope fractionation: dissolution, adsorption, desorption, precipitation, polymerization and depolymerization. Model best fits are obtained when combining the effects of dissolution/precipitation, and adsorption/desorption onto secondary minerals. These processes are inferred to produce an equilibrium isotope fractionation, with an enrichment in heavy Mo isotopes in the liquid phase and in light isotopes in the solid phase. Quantification of Mo isotope fractionation resulting from uranium leaching is thus a promising tool to trace the origin and transformation of nuclear materials. Our observations of Mo leaching are also consistent with observations of natural Mo isotope fractionation taking place during chemical weathering in terrestrial environments where the role of secondary processes such as adsorption is significant.

Stress and Sealing Performance Analysis of Containment Vessel

DOE Office of Scientific and Technical Information (OSTI.GOV)

WU, TSU-TE

2005-05-24

This paper presents a numerical technique for analyzing the containment vessel subjected to the combined loading of closure-bolt torque and internal pressure. The detailed stress distributions in the O-rings generated by both the torque load and the internal pressure can be evaluated by using this method. Consequently, the sealing performance of the O-rings can be determined. The material of the O-rings can be represented by any available constitutive equation for hyperelastic material. In the numerical calculation of this paper, the form of the Mooney-Rivlin strain energy potential is used. The technique treats both the preloading process of bolt tightening andmore » the application of internal pressure as slow dynamic loads. Consequently, the problem can be evaluated using explicit numerical integration scheme.« less

Comparison of selective flocculation of low grade goethitic iron ore fines using natural and synthetic polymers and a graft copolymer

NASA Astrophysics Data System (ADS)

Tudu, Kichakeswari; Pal, Sagar; Mandre, N. R.

2018-05-01

This study aims to beneficiate low grade goethitic iron ore fines using a selective flocculation process. Selective flocculation studies were conducted using different polymers such as starch amylopectin (AP), poly acrylic acid (PAA), and a graft copolymer (AP-g-PAA). The obtained results were analyzed; they indicate the enhancement of the iron ore grade from 58.49% to 67.52% using AP-g-PAA with a recovery of 95.08%. In addition, 64.45% Fe with a recovery of 88.79% was obtained using AP. Similarly, using PAA, the grade increased to 63.46% Fe with a recovery of 82.10%. The findings are also supported by characterizing concentrates using X-ray diffraction (XRD) and electron probe microanalysis (EPMA) techniques.

The Structure of Reclaiming Warehouse of Minerals at Open-Cut Mines with the Use Combined Transport

NASA Astrophysics Data System (ADS)

Ikonnikov, D. A.; Kovshov, S. V.

2017-07-01

In the article performed an analysis of ore reclaiming and overloading point characteristics at modern opencast mines. Ore reclaiming represents the most effective way of stability support of power-intensive and expensive technological dressing process, and, consequently, of maintenance of the optimal production and set-up parameters of extraction and quality of finished product. The paper proposed the construction of the warehouse describing the technology of its creation. Equipment used for the warehouse described in detail. All stages of development and operation was shown. Advantages and disadvantages of using mechanical shovel excavator and hydraulic excavator “backdigger” as a reloading and reclaiming equipment was compared. Ore reclaiming and overloading point construction at cyclical and continuous method of mining using a hydraulic excavator “backdigger” was proposed.

Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

USGS Publications Warehouse

Paktunc, D.; Foster, A.; Heald, S.; Laflamme, G.

2004-01-01

The knowledge of mineralogy and molecular structure of As is needed to better understand the stability of As in wastes resulting from processing of gold ores. In this study, optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction and X-ray absorption fine structure (XAFS) spectroscopy (including both XANES and EXAFS regimes) were employed to determine the mineralogical composition and local coordination environment of As in gold ores and process tailings from bench-scale tests designed to mimic a common plant practice. Arsenic-bearing minerals identified in the ores and tailings include iron (III) oxyhydroxides, scorodite (FeAsO4??2H2O), ferric arsenates, arseniosiderite (Ca2Fe3 (AsO4)3O2??3H2O), Ca-Fe arsenates, pharmacosiderite (KFe4 (AsO4)3(OH)4??6-7H2O), jarosite (K2Fe6(SO4)4 (OH)12) and arsenopyrite (FeAsS). Iron (III) oxyhydroxides contain variable levels of As from trace to about 22 wt% and Ca up to approximately 9 wt%. Finely ground ore and tailings samples were examined by bulk XAFS and selected mineral grains were analyzed by microfocused XAFS (micro-EXAFS) spectroscopy to reconcile the ambiguities of multiple As sources in the complex bulk EXAFS spectra. XANES spectra indicated that As occurs as As5+in all the samples. Micro-EXAFS spectra of individual iron (III) oxyhydroxide grains with varying As concentrations point to inner-sphere bidentate-binuclear arsenate complexes as the predominant form of As. There are indications for the presence of a second Fe shell corresponding to bidentate-mononuclear arrangement. Iron (III) oxyhydroxides with high As concentrations corresponding to maximum adsorption densities probably occur as nanoparticles. The discovery of Ca atoms around As in iron (III) oxyhydroxides at interatomic distances of 4.14-4.17 A?? and the coordination numbers suggest the formation of arseniosiderite-like nanoclusters by coprecipitation rather than simple adsorption of Ca onto iron (III) oxyhydroxides. Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore. ?? 2004 Elsevier Ltd.

Speciation and characterization of arsenic in gold ores and cyanidation tailings using X-ray absorption spectroscopy

NASA Astrophysics Data System (ADS)

Paktunc, Dogan; Foster, Andrea; Heald, Steve; Laflamme, Gilles

2004-03-01

The knowledge of mineralogy and molecular structure of As is needed to better understand the stability of As in wastes resulting from processing of gold ores. In this study, optical microscopy, scanning electron microscopy, electron microprobe, X-ray diffraction and X-ray absorption fine structure (XAFS) spectroscopy (including both XANES and EXAFS regimes) were employed to determine the mineralogical composition and local coordination environment of As in gold ores and process tailings from bench-scale tests designed to mimic a common plant practice. Arsenic-bearing minerals identified in the ores and tailings include iron (III) oxyhydroxides, scorodite (FeAsO 4·2H 2O), ferric arsenates, arseniosiderite (Ca 2Fe 3(AsO 4) 3O 2·3H 2O), Ca-Fe arsenates, pharmacosiderite (KFe 4(AsO 4) 3(OH) 4·6-7H 2O), jarosite (K 2Fe 6(SO 4) 4(OH) 12) and arsenopyrite (FeAsS). Iron (III) oxyhydroxides contain variable levels of As from trace to about 22 wt% and Ca up to approximately 9 wt%. Finely ground ore and tailings samples were examined by bulk XAFS and selected mineral grains were analyzed by microfocused XAFS (micro-EXAFS) spectroscopy to reconcile the ambiguities of multiple As sources in the complex bulk EXAFS spectra. XANES spectra indicated that As occurs as As 5+in all the samples. Micro-EXAFS spectra of individual iron (III) oxyhydroxide grains with varying As concentrations point to inner-sphere bidentate-binuclear arsenate complexes as the predominant form of As. There are indications for the presence of a second Fe shell corresponding to bidentate-mononuclear arrangement. Iron (III) oxyhydroxides with high As concentrations corresponding to maximum adsorption densities probably occur as nanoparticles. The discovery of Ca atoms around As in iron (III) oxyhydroxides at interatomic distances of 4.14-4.17 Å and the coordination numbers suggest the formation of arseniosiderite-like nanoclusters by coprecipitation rather than simple adsorption of Ca onto iron (III) oxyhydroxides. Correlation of Ca with As in iron (III) oxyhydroxides as determined by electron microprobe analysis supports the coprecipitate origin for the presence of Ca in iron (III) oxyhydroxides. The samples containing higher abundances of ferric arsenates released higher As concentrations during the cyanidation tests. The presence of highly soluble ferric arsenates and Ca-Fe arsenates, and relatively unstable iron (III) oxyhydroxides with Fe/As molar ratios of less than 4 in the ore and process tailings suggests that not only the tailings in the impoundment will continue to release As, but also there is the potential for mobilization of As from the natural sources such as the unmined ore.

Recent Advances and Research Status in Energy Conservation of Iron Ore Sintering in China

NASA Astrophysics Data System (ADS)

Wang, Yao-Zu; Zhang, Jian-Liang; Liu, Zheng-Jian; Du, Cheng-Bo

2017-11-01

For the ferrous burden of blast furnaces in China, sinter generally accounts for more than 70% and the sintering process accounts for approximately 6-10% of the total energy consumption of the iron and steel enterprise. Therefore, saving energy during the sintering process is important to reduce the energy consumption in the iron and steel industry. This paper aims to illustrate recent advances and the research status of energy conservation of iron ore sintering in China. It focuses on the development and application of energy-saving technologies such as the composite agglomeration process, sintering with high-proportion flue gas recirculation sintering, recovery of sensible heat from the sinter cooling process, homogeneous deep-bed sintering technology, and comprehensive treatment technology of leakage of sintering. Moreover, some suggestions for the future development of energy-saving technologies are put forward.

An investigation into heterogeneity in a single vein-type uranium ore deposit: Implications for nuclear forensics.

PubMed

Keatley, A C; Scott, T B; Davis, S; Jones, C P; Turner, P

2015-12-01

Minor element composition and rare earth element (REE) concentrations in nuclear materials are important as they are used within the field of nuclear forensics as an indicator of sample origin. However recent studies into uranium ores and uranium ore concentrates (UOCs) have shown significant elemental and isotopic heterogeneity from a single mine site such that some sites have shown higher variation within the mine site than that seen between multiple sites. The elemental composition of both uranium and gangue minerals within ore samples taken along a single mineral vein in South West England have been measured and reported here. The analysis of the samples was undertaken to determine the extent of the localised variation in key elements. Energy Dispersive X-ray spectroscopy (EDS) was used to analyse the gangue mineralogy and measure major element composition. Minor element composition and rare earth element (REE) concentrations were measured by Electron Probe Microanalysis (EPMA). The results confirm that a number of key elements, REE concentrations and patterns used for origin location do show significant variation within mine. Furthermore significant variation is also visible on a meter scale. In addition three separate uranium phases were identified within the vein which indicates multiple uranium mineralisation events. In light of these localised elemental variations it is recommended that representative sampling for an area is undertaken prior to establishing the REE pattern that may be used to identify the originating mine for an unknown ore sample and prior to investigating impact of ore processing on any arising REE patterns. Copyright © 2015 Elsevier Ltd. All rights reserved.

Reduction of phosphate ores by carbon: Part I. Process variables for design of rotary kiln system

NASA Astrophysics Data System (ADS)

Mu, Jacob; Leder, Frederic; Park, Won C.; Hard, Robert A.; Megy, Joseph; Reiss, Howard

1986-12-01

Feasibility is established for the reduction of phosphate ores in a rotary kiln, avoiding electric submerged arc furnace technology. This represents a totally new approach to phosphoric acid. Reduction rates of phosphate ore-silica mixtures by carbon in the temperature range of 1100 to 1500 °C under several CO partial pressures in nitrogen were measured in thermogravimetric analyzers. Parameters such as carbon and silica contents, particle and pellet sizes, and gas flow rate were also evaluated with various domestic and foreign phosphate ores. Furthermore, a variety of carbon sources such as subbituminous coals, bituminous coals, anthracite, petroleum coke, and metallurgical coke were tested as reducing agents. Thermodynamic considerations elucidate the temperature dependence of overall conversion as well as the role of excess silica in establishing equilibrium pressure. These findings provide the background for analysis of the kinetics of conversion in Part II of this work. These studies, in conjunction with a previously published work, indicate the importance of intergranular melt phases in the kinetics of otherwise solid state reactions.

Carbothermic Aluminum Production Using Scrap Aluminum As A Coolant

DOEpatents

LaCamera, Alfred F.

2002-11-05

A process for producing aluminum metal by carbothermic reduction of alumina ore. Alumina ore is heated in the presence of carbon at an elevated temperature to produce an aluminum metal body contaminated with about 10-30% by wt. aluminum carbide. Aluminum metal or aluminum alloy scrap then is added to bring the temperature to about 900-1000.degree. C. and precipitate out aluminum carbide. The precipitated aluminum carbide is filtered, decanted, or fluxed with salt to form a molten body having reduced aluminum carbide content.

ION EXCHANGE TESTS ON LIQUOR AND PULPS PRODUCED FROM UTEX ORES. Topical Report

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hollis, E.T.; Pickwick, F.J. Jr.; Kazanjian, A.R.

1954-07-30

Uranium leach liquors produced from Utex ore by cold leaching, hot leaching, and pugging proved amenable to the lon exchange process, Higher resin loadings were obtained rom the cold leach liquors than from the hot leach and pug liquors. In general, the less vigorous leaching conditions produced liquors which gave the highest resin loadings. In addition, a resin-in-pulp system was operated using the lucite Winchester cells on Utex pulp produced by cold leaching. Satisfactory loadings were obtained. (auth)

Lake Superior, Deluth, MN

NASA Image and Video Library

1973-06-22

SL2-05-454 (22 June 1973) --- This view shows the west end of Lake Superior and Duluth, MN (47.0N, 91.0W). Portions of Minnesota, Michigan and Ontario, Canada are in the scene. The Duluth metropolitan area is at the west end of the lake. The discoloration plume in the water at Duluth is the result of tailings from the iron ore smelters that process the iron ore from the nearby open pit mines seen near the upper left corner of the photo. Photo credit: NASA

Experimental design and optimization of leaching process for recovery of valuable chemical elements (U, La, V, Mo, Yb and Th) from low-grade uranium ore.

PubMed

Zakrzewska-Koltuniewicz, Grażyna; Herdzik-Koniecko, Irena; Cojocaru, Corneliu; Chajduk, Ewelina

2014-06-30

The paper deals with experimental design and optimization of leaching process of uranium and associated metals from low-grade, Polish ores. The chemical elements of interest for extraction from the ore were U, La, V, Mo, Yb and Th. Sulphuric acid has been used as leaching reagent. Based on the design of experiments the second-order regression models have been constructed to approximate the leaching efficiency of elements. The graphical illustrations using 3-D surface plots have been employed in order to identify the main, quadratic and interaction effects of the factors. The multi-objective optimization method based on desirability approach has been applied in this study. The optimum condition have been determined as P=5 bar, T=120 °C and t=90 min. Under these optimal conditions, the overall extraction performance is 81.43% (for U), 64.24% (for La), 98.38% (for V), 43.69% (for Yb) and 76.89% (for Mo) and 97.00% (for Th). Copyright © 2014 Elsevier B.V. All rights reserved.

Behavior of uranium under conditions of interaction of rocks and ores with subsurface water

NASA Astrophysics Data System (ADS)

Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

2007-10-01

The behavior of uranium during interaction of subsurface water with crystalline rocks and uranium ores is considered in connection with the problem of safe underground insulation of spent nuclear fuel (SNF). Since subsurface water interacts with crystalline rocks formed at a high temperature, the mineral composition of these rocks and uranium species therein are thermodynamically unstable. Therefore, reactions directed toward the establishment of equilibrium proceed in the water-rock system. At great depths that are characterized by hindered water exchange, where subsurface water acquires near-neutral and reducing properties, the interaction is extremely sluggish and is expressed in the formation of micro- and nanoparticles of secondary minerals. Under such conditions, the slow diffusion redistribution of uranium with enrichment in absorbed forms relative to all other uranium species is realized as well. The products of secondary alteration of Fe- and Ti-bearing minerals serve as the main sorbents of uranium. The rate of alteration of minerals and conversion of uranium species into absorbed forms is slow, and the results of these processes are insignificant, so that the rocks and uranium species therein may be regarded as unaltered. Under reducing conditions, subsurface water is always saturated with uranium. Whether water interacts with rock or uranium ore, the equilibrium uranium concentration in water is only ≤10-8 mol/l. Uraninite ore under such conditions always remains stable irrespective of its age. The stability conditions of uranium ore are quite suitable for safe insulation of SNF, which consists of 95% uraninite (UO2) and is a confinement matrix for all other radionuclides. The disposal of SNF in massifs of crystalline rocks at depths below 500 m, where reducing conditions are predominant, is a reliable guarantee of high SNF stability. Under oxidizing conditions of the upper hydrodynamic zone, the rate of interaction of rocks with subsurface water increases by orders of magnitude and subsurface water is commonly undersaturated with uranium. Uranium absorbed by secondary minerals, particularly by iron hydroxides and leucoxene, is its single stable species under oxidizing conditions. The impact of oxygen-bearing water leads to destruction of uranium ore. This process is realized simultaneously at different hypsometric levels even if the permeability of the medium is variable in both the lateral and vertical directions. As a result, intervals containing uranyl minerals and relics of primary uranium ore are combined in ore-bearing zones with intervals of completely dissolved uranium minerals. A wide halo of elevated uranium contents caused by sorption is always retained at the location of uranium ore entirely destroyed by weathering. Uranium ore commonly finds itself in the aeration zone due to technogenic subsidence of the groundwater table caused by open-pit mining or pumping out of water from underground mines. The capillary and film waters that interact with rocks and ores in this zone are supplemented by free water filtering along fractures when rain falls or snow is thawing. The interaction of uranium ore with capillary water results in oxidation of uraninite, accompanied by loosening of the mineral surface, formation of microfractures, and an increase in solubility with enrichment of capillary water in uranium up to 10-4 mol/l. Secondary U(VI) minerals, first of all, uranyl hydroxides and silicates, replace uraninite, and uranium undergoes local diffusion redistribution with its sorption by secondary minerals of host rocks. The influx of free water facilitates the complete dissolution of primary and secondary uranium minerals, the removal of uranium at the sites of groundwater discharge, and its redeposition under reducing conditions at a greater depth. It is evident that the conditions of the upper hydrodynamic zone and the aeration zone are unfit for long-term insulation of SNF and high-level wastes because, after the failure of containers, the leakage of radionuclides into the environment becomes inevitable.

Hydrothermal fluoride and chloride complexation of indium: an EXAFS study

NASA Astrophysics Data System (ADS)

Loges, Anselm; Testemale, Denis; Huotari, Simo; Honkanen, Ari-Pekka; Potapkin, Vasily; Wagner, Thomas

2017-04-01

Indium (In) is one of the geochemically lesser studied ore metals, and the factors that control the hydrothermal transport and deposition are largely unknown. It has no ore deposits of its own and is commonly mined as a by-product of Zn ores, and there are very few minerals that contain In as an essential structural component. Recently, industrial application of In in touch screen devices has drastically increased demand, which is projected to exceed supply from the current sources in the near future. Since the most relevant In sources are hydrothermal sphalerite ores and to a lesser extent hydrothermal greisen-type deposits in evolved granitic plutons, the aqueous geochemistry of In is of particular interest for understanding its ore forming processes. As a first step towards a comprehensive model for hydrothermal In solubility and speciation, we have studied In speciation in fluoride and chloride bearing solutions at 30-400˚ C and 500 bar using X-Ray Absorption Spectroscopy (XAS) measurements. The experiments were conducted in a unique hydrothermal autoclave setup at beamline BM30B-FAME at the European Synchrotron Radiation Facility (ESRF) in Grenoble, France. Our results show that the complexation of In changes dramatically between 30 and 400˚ C. Below ca. 200˚ C, fluoride complexes are the most stable ones, but they break down at higher temperatures. Chloride complexes on the other hand become increasingly stable with increasing temperature. This behavior has interesting consequences for natural ore forming systems. In Cl-rich systems (e.g. massive sulfide ores formed in sea floor environments), cooling can be an effective precipitating mechanism. In F-rich systems, fluoride complexation can extend In mobility to low temperatures and In will only precipitate when F is effectively removed from the fluid, e.g. by mixing with a Ca-rich fluid and precipitation of fluorite (CaF2) as is commonly observed in skarn or greisen-type deposits. Due to In complexing with both F and Cl, depending on temperature, In distribution also has great potential as a fluid chemistry/temperature indicator in a wide range of different hydrothermal ore-forming systems.

Gold paragenesis and chemistry at Batu Hijau, Indoneisa: implications for gold-rich porphyry copper deposits

NASA Astrophysics Data System (ADS)

Arif, J.; Baker, T.

2004-10-01

Gold is an important by-product in many porphyry-type deposits but the distribution and chemistry of gold in such systems remains poorly understood. Here we report the results of petrographic, electron microprobe, laser ablation inductively coupled plasma mass spectrometry (LA-ICP-MS), and flotation test studies of gold and associated copper sulfides within a paragenetic framework from the world-class Batu Hijau (914 mt @ 0.53% Cu, 0.40 g/t Au) porphyry copper gold deposit, Indonesia. Unlike many other porphyry copper gold deposits, early copper minerals (bornite digenite chalcocite) are well preserved at Batu Hijau and the chalcopyrite pyrite overprint is less developed. Hence, it provides an excellent opportunity to study the entire gold paragenesis of the porphyry system. In 105 polished thin sections, 699 native gold grains were identified. Almost all of the native gold grains occurred either within quartz veins, attached to sulfide, or as free gold along quartz or silicate grain boundaries. The native gold grains are dominantly round in shape and mostly 1 12 μm in size. The majority of gold was deposited during the formation of early ‘A’ veins and is dominantly associated with bornite rather than chalcopyrite. The petrographic and LA-ICP-MS study results indicate that in bornite-rich ores gold mostly occurs within copper sulfide grains as invisible gold (i.e., within the sulfide structure) or as native gold grains. In chalcopyrite-rich ores gold mostly occurs as native gold grains with lesser invisible gold. Petrographic observations also indicate a higher proportion of free gold (native gold not attached to any sulfide) in chalcopyrite-rich ores compared to bornite rich ores. The pattern of free gold distribution appears to correlate with the flotation test data, where the average gold recovery value from chalcopyrite-rich ores is consistently lower than bornite-rich ores. Our data suggest that porphyry copper-gold deposits with chalcopyrite-rich ores are more likely to have a higher proportion of free gold and may require different ore processing strategies.

Total Ore Processing Integration and Management

DOE Office of Scientific and Technical Information (OSTI.GOV)

Leslie Gertsch; Richard Gertsch

2006-01-30

This report outlines the technical progress achieved for project DE-FC26-03NT41785 (Total Ore Processing Integration and Management) during the period 01 July through 30 September of 2005. This ninth quarterly report discusses the activities of the project team during the period 1 July through 30 September 2005. Richard Gertsch's unexpected death due to natural causes while in Minnesota to work on this project has temporarily slowed progress. Statistical analysis of the Minntac Mine data set for late 2004 is continuing. Preliminary results raised several questions that could be amenable to further study. Detailed geotechnical characterization is being applied to improve themore » predictability of mill and agglomerator performance at Hibtac Mine.« less

Linking geological and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria.

PubMed

Plumlee, Geoffrey S; Durant, James T; Morman, Suzette A; Neri, Antonio; Wolf, Ruth E; Dooyema, Carrie A; Hageman, Philip L; Lowers, Heather A; Fernette, Gregory L; Meeker, Gregory P; Benzel, William M; Driscoll, Rhonda L; Berry, Cyrus J; Crock, James G; Goldstein, Harland L; Adams, Monique; Bartrem, Casey L; Tirima, Simba; Behbod, Behrooz; von Lindern, Ian; Brown, Mary Jean

2013-06-01

In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.

Linking Geological and Health Sciences to Assess Childhood Lead Poisoning from Artisanal Gold Mining in Nigeria

PubMed Central

Durant, James T.; Morman, Suzette A.; Neri, Antonio; Wolf, Ruth E.; Dooyema, Carrie A.; Hageman, Philip L.; Lowers, Heather A.; Fernette, Gregory L.; Meeker, Gregory P.; Benzel, William M.; Driscoll, Rhonda L.; Berry, Cyrus J.; Crock, James G.; Goldstein, Harland L.; Adams, Monique; Bartrem, Casey L.; Tirima, Simba; Behbod, Behrooz; von Lindern, Ian; Brown, Mary Jean

2013-01-01

Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally. PMID:23524139

Tectonics and metallogenic provinces

USGS Publications Warehouse

Guild, P.W.

1983-01-01

Various theories have been advanced to explain the well-known uneven distribution of metals and ore-deposit types in space and time. Primordial differences in the mantle, preferential concentration of elements in the crust, the prevalence of ore-forming processes at certain times and (or) places, and combinations of one or several of these factors have all been called upon to account for the "metallogenic provinces," which can be defined loosely as regions containing similar deposits of one or a group of metals or minerals. Because many, perhaps most, provinces have complex, multistage origins, the relative importance of inheritance vs. process is still controversial. In recent years the geographic relationship of many geologically young provinces to present-day plate-tectonic positions (accreting or consuming margins, intraplate structures, etc.) has been widely recognized, and the presumption is strong that older provinces had similar relationships to former plates. As most ore deposits resulted from a favorable conjunction of geological processes that are no longer operative, elucidation of their genesis requires reconstruction of the geologic history of the province, with particular emphasis on events coeval with mineralization. Tectonic analysis is an important aspect of this reconstruction; data from orbiting satellites have contributed greatly to this analysis, as the voluminous literature of the past decade testifies. Both the synoptic view of large areas and the ability to emphasize faint contrasts have revealed linear, curvilinear, and circular features not previously recognized from field studies. Some of these undoubtedly reflect basement structures that have contributed to the development, or limit the extent, of metallogenic provinces. Their recognition and delineation will be increasingly valuable to the assessment of resources available and as guides to exploration for the ores needed by future generations. ?? 1983.

Development of Effective Connectivity during Own- and Other-Race Face Processing: A Granger Causality Analysis

PubMed Central

Zhou, Guifei; Liu, Jiangang; Ding, Xiao Pan; Fu, Genyue; Lee, Kang

2016-01-01

Numerous developmental studies have suggested that other-race effect (ORE) in face recognition emerges as early as in infancy and develops steadily throughout childhood. However, there is very limited research on the neural mechanisms underlying this developmental ORE. The present study used Granger causality analysis (GCA) to examine the development of children's cortical networks in processing own- and other-race faces. Children were between 3 and 13 years. An old-new paradigm was used to assess their own- and other-race face recognition with ETG-4000 (Hitachi Medical Co., Japan) acquiring functional near infrared spectroscopy (fNIRS) data. After preprocessing, for each participant and under each face condition, we obtained the causal map by calculating the weights of causal relations between the time courses of [oxy-Hb] of each pair of channels using GCA. To investigate further the differential causal connectivity for own-race faces and other-race faces at the group level, a repeated measure analysis of variance (ANOVA) was performed on the GCA weights for each pair of channels with the face race task (own-race face vs. other-race face) as the within-subject variable and the age as a between-subject factor (continuous variable). We found an age-related increase in functional connectivity, paralleling a similar age-related improvement in behavioral face processing ability. More importantly, we found that the significant differences in neural functional connectivity between the recognition of own-race faces and that of other-race faces were modulated by age. Thus, like the behavioral ORE, the neural ORE emerges early and undergoes a protracted developmental course. PMID:27713696

Linking geology and health sciences to assess childhood lead poisoning from artisanal gold mining in Nigeria

USGS Publications Warehouse

Plumlee, Geoffrey S.; Durant, James T.; Morman, Suzette A.; Neri, Antonio; Wolf, Ruth E.; Dooyema, Carrie A.; Hageman, Philip L.; Lowers, Heather; Fernette, Gregory L.; Meeker, Gregory P.; Benzel, William M.; Driscoll, Rhonda L.; Berry, Cyrus J.; Crock, James G.; Goldstein, Harland L.; Adams, Monique; Bartrem, Casey L.; Tirima, Simba; Behrooz, Behbod; von Lindern, Ian; Brown, Mary Jean

2013-01-01

Background: In 2010, Médecins Sans Frontières discovered a lead poisoning outbreak linked to artisanal gold processing in northwestern Nigeria. The outbreak has killed approximately 400 young children and affected thousands more. Objectives: Our aim was to undertake an interdisciplinary geological- and health-science assessment to clarify lead sources and exposure pathways, identify additional toxicants of concern and populations at risk, and examine potential for similar lead poisoning globally. Methods: We applied diverse analytical methods to ore samples, soil and sweep samples from villages and family compounds, and plant foodstuff samples. Results: Natural weathering of lead-rich gold ores before mining formed abundant, highly gastric-bioaccessible lead carbonates. The same fingerprint of lead minerals found in all sample types confirms that ore processing caused extreme contamination, with up to 185,000 ppm lead in soils/sweep samples and up to 145 ppm lead in plant foodstuffs. Incidental ingestion of soils via hand-to-mouth transmission and of dusts cleared from the respiratory tract is the dominant exposure pathway. Consumption of water and foodstuffs contaminated by the processing is likely lesser, but these are still significant exposure pathways. Although young children suffered the most immediate and severe consequences, results indicate that older children, adult workers, pregnant women, and breastfed infants are also at risk for lead poisoning. Mercury, arsenic, manganese, antimony, and crystalline silica exposures pose additional health threats. Conclusions: Results inform ongoing efforts in Nigeria to assess lead contamination and poisoning, treat victims, mitigate exposures, and remediate contamination. Ore deposit geology, pre-mining weathering, and burgeoning artisanal mining may combine to cause similar lead poisoning disasters elsewhere globally.

PROCESS FOR RECOVERY OF CONSTITUENTS OF ORES

DOEpatents

McCullough, R.F.

1959-05-01

A process for U recovery from leached zone material is described. Calcination with alkali metal carbonate at 600 to 2000 deg F followed by digestion with H/sub 2/SO/sub 4/ and filtration forms the basis of the process. (T.R.H.)

Role of manganese dioxide in the recovery of oxide-sulphide zinc ore.

PubMed

Yang, Kun; Zhang, Libo; Zhu, Xingcai; Peng, Jinhui; Li, Shiwei; Ma, Aiyuan; Li, Haoyu; Zhu, Fei

2018-02-05

In this article, the role of MnO 2 in the recovery of oxide-sulphide zinc ore discussed. Through adopting various modern analysis techniques (such as X-ray diffraction pattern, X-ray photoelectron spectroscopy, scanning electron microscope, energy dispersive X-ray analysis, and fourier transform infrared spectroscopy), the function and mechanism of MnO 2 during the phase transformation process is found out. Thermodynamic mechanisms involved in the phase transformation process with or without addition of manganese dioxide investigated by exploiting the Equilib module of FactSage. What's more, XRD patterns, XPS spectra and SEM-EDAX analyses of zinc calcines verify well the calculations of FactSage. Results reveal that the addition of MnO 2 will produce an aggregation of ZnMn 2 O 4 , a valuable energy material, while roasting on its own, results in generating undesirable Zn 2 SiO 4 , the oxidation degree being relatively low. Moreover, XRD pattern of zinc calcine and FT-IR spectrum of yellow product collected in the calcination process prove that the sulphur-fixing value of the additive MnO 2 , which can promote transforming to the elemental sulphur. The volatile S can be collected through a simple guiding device. In this process, the emission of SO 2 effectively avoids, thus MnO 2 deems as a potential additive in the recovery of oxide-sulphide zinc ore. Copyright © 2017. Published by Elsevier B.V.

Control of Rock Mechanics in Underground Ore Mining

NASA Astrophysics Data System (ADS)

Golik, V. I.; Efremenkov, A. B.

2017-07-01

Performance indicators in underground mining of thick iron fields can be insufficient since geo-mechanic specifics of ore-hosting fields might be considered inadequately, as a consequence, critical deformations and even earth’s surface destruction are possible, lowering the indicators of full subsurface use, this way. The reason for it is the available approach to estimating the performance of mining according to ore excavation costs, without assessing losses of valuable components and damage to the environment. The experimental approach to the problem is based on a combination of methods to justify technical capability and performance of mining technology improvement with regard to geomechanical factors. The main idea of decisions to be taken is turning geo-materials into the condition of triaxial compression via developing the support constructions of blocked up structural rock block. The study was carried out according to an integrated approach based on the analysis of concepts, field observations, and simulation with the photo-elastic materials in conditions of North Caucasus deposits. A database containing information on the deposit can be developed with the help of industrial experiments and performance indicators of the field can be also improved using the ability of ore-hosting fields to develop support constructions, keeping the geo-mechanical stability of the system at lower cost, avoiding ore contamination at the processing stage. The proposed model is a specific one because an adjustment coefficient of natural and anthropogenic stresses is used and can be adopted for local conditions. The relation of natural to anthropogenic factors can make more precise the standards of developed, prepared and ready to excavation ore reserves relying on computational methods. It is possible to minimize critical stresses and corresponding deformations due to dividing the ore field into sectors safe from the standpoint of geo-mechanics, and using less cost-demanding ways of keeping rock massif stable.

A REAL-TIME COAL CONTENT/ORE GRADE (C2OC) SENSOR

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rand Swanson

2005-04-01

This is the final report of a three year DOE funded project titled ''A real-time coal content/ore grade (C{sub 2}OG) sensor''. The sensor, which is based on hyperspectral imaging technology, was designed to give a machine vision assay of ore or coal. Sensors were designed and built at Resonon, Inc., and then deployed at the Stillwater Mining Company core room in southcentral Montana for analyzing platinum/palladium ore and at the Montana Tech Spectroscopy Lab for analyzing coal and other materials. The Stillwater sensor imaged 91' of core and analyzed this data for surface sulfides which are considered to be pathfindermore » minerals for platinum/palladium at this mine. Our results indicate that the sensor could deliver a relative ore grade provided tool markings and iron oxidation were kept to a minimum. Coal, talc, and titanium sponge samples were also imaged and analyzed for content and grade with promising results. This research has led directly to a DOE SBIR Phase II award for Resonon to develop a down-hole imaging spectrometer based on the same imaging technology used in the Stillwater core room C{sub 2}OG sensor. The Stillwater Mining Company has estimated that this type of imaging system could lead to a 10% reduction in waste rock from their mine and provide a $650,000 benefit per year. The proposed system may also lead to an additional 10% of ore tonnage, which would provide a total economic benefit of more than $3.1 million per year. If this benefit could be realized on other metal ores for which the proposed technology is suitable, the possible economic benefits to U.S. mines is over $70 million per year. In addition to these currently lost economic benefits, there are also major energy losses from mining waste rock and environmental impacts from mining, processing, and disposing of waste rock.« less

(234)U/(238)U signatures associated with uranium ore bodies: part 1 Ranger 3.

PubMed

Lowson, Richard T; McIntyre, Mark G

2013-04-01

The Ranger 3 ore body is an early Proterozoic U ore body in the Alligator Rivers U province, Northern Territory, Australia. It has surface expression with a redox front located between 30 and 50 m below the surface. The ground water U concentration and (234)U/(238)U AR signature in the top 10 m of the weathered zone are reported for 357 samples collected over 4 wet seasons, at 5 depths, along a transect in-line with the hydraulic gradient and along the centre line of the ore body and its associated dispersion halo. The results show that the weathered zone displays a general U isotope feature for this type of ore body with the (234)U/(238)U AR for the ground water and amorphous phase of the solid matrix being less than 1. The ground water (234)U/(238)U AR is independent of the annual monsoonal climate and depth within the range surface to 10 m. In the vicinity of the U ore body the ground water (234)U/(238)U AR is 0.75 and is very similar to the (234)U/(238)U AR of the amorphous phase of the solid (0.76). The (234)U/(238)U ARs of the amorphous phase and ground water rise and separate to values of 0.88 and 1.02 at the end of the transect. The rise and separation in (234)U/(238)U AR are interpreted as evidence that the source of the U in the ground water is from the water-soluble sub-phase of the amorphous phase and that the ground water flow is too fast to allow the processes occurring across the solid-water interface to reach chemical equilibrium. The data set is a robust characterisation of the coarse and fine detail of the (234)U/(238)U AR signature in the weathered zone of U ore bodies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Study on the pre-treatment of oxidized zinc ore prior to flotation

NASA Astrophysics Data System (ADS)

He, Dong-sheng; Chen, Yun; Xiang, Ping; Yu, Zheng-jun; Potgieter, J. H.

2018-02-01

The pre-treatment of zinc oxide bearing ores with high slime content is important to ensure that resources are utilized optimally. This paper reports an improved process using hydrocyclone de-sliming, dispersion reagents, and magnetic removal of iron minerals for the pre-treatment of zinc oxide ore with a high slime and iron content, and the benefits compared to traditional technologies are shown. In addition, this paper investigates the damage related to fine slime and iron during zinc oxide flotation, the necessity of using hydrocyclone de-sliming together with dispersion reagents to alleviate the influence of slime, and interactions among hydrocyclone de-sliming, reagent dispersion, and magnetic iron removal. Results show that under optimized operating conditions the entire beneficiation technology results in a flotation concentrate with a Zn grade of 34.66% and a recovery of 73.41%.

Time constraints on post-rift evolution of the Southwest Indian passive margin from ^{40}Ar-^{39Ar dating of supergene K-Mn oxides

NASA Astrophysics Data System (ADS)

Bonnet, Nicolas; Arnaud, Nicolas; Beauvais, Anicet; Chardon, Dominique

2013-04-01

The high-elevation passive margin of Southwest India is marked by the Western Ghats escarpment, which separates the coastal domain from the low-relief East-dipping Mysore plateau. The escarpment has evolved from the Seychelles rifting at ~ 63 Ma following the Deccan traps volcanic event at ~ 65-63 Ma. This escarpment results from differential erosion processes across the passive margin, the rate and timing of which depend upon whether the margin has evolved according to a model of downwarped or rising flank topography. We explore the post-rift evolution of the South Indian passive margin through the characterisation of stepped relicts of lateritic paleosurfaces across that margin, and notably by 40Ar-39Ar dating of in-situ formed K-Mn oxides in supergene Mn-ore deposits carried by these paleosurfaces. The genesis and maturation of Mn-ore deposits are generally linked to progressive weathering processes of the paleosurfaces, which expose them. Dating of K-Mn oxides thus document the timing of these processes [1], and potentially the ages of the altered paleosurface. Moreover, the elevation differences between successive lateritic paleosurfaces of different ages may provide denudation rates for the considered time spans. Previous work (e.g., [2]) and our own field investigations, allow identifying three main lateritic paleosurfaces on the plateau at altitude ranges of 1000-900 m (S2), 900-800 m (S3) and 800-700 m (S3d), and a lower paleosurface in the coastal domain at 150-50 m (S4). K-Mn oxides (cryptomelane) were sampled in Mn ore deposits from different paleosurfaces, particularly in the coastal area around Goa on S4 and in Sandur and Shimoga Mn-ore deposits exposed on S2 and S3. The 40Ar-39Ar ages obtained from carefully characterised mineralogical assemblages range from ~ 26 to ~ 36 Ma in the Sandur Mn-ore deposit indicating intense lateritic weathering processes at the Eocene-Oligocene transition underneath paleosurface S2. Similar ages of ~ 24 and ~ 32 Ma are obtained in two Shimoga Mn ore deposits carried by S3 and S2, respectively. A younger age (~ 21 Ma) is also obtained in a Goa deposit carried by S4. These first results suggest that the Western Ghats passive margin escarpment was established at the latest by early Miocene and that at least part of the inland Mysore plateau morphogenesis was achieved at that time. [1] Beauvais A. et al., Journal of Geophysical Research 113, F04007, 2008. [2] Gunnell, Y., Basin Research 10, 281-310, 1998.

The Use of Traditional Hydrologic Field Techniques as a Means of Quantifying Mine-Related Contamination Impacts on a Surface Water Body, Norrbotten County, Sweden

NASA Astrophysics Data System (ADS)

Little, S. F. B.; Walder, I. F.; Cadol, D. D.

2016-12-01

The Malmberget/Vitåfors mining facility, located in Norrbotten County, Sweden, is the world's second largest underground iron ore mine, comprised of roughly 20 steeply dipping magnetite-hematite ore lenses, with an underground area of approximately 5 x 2.5km. Since its' opening in 1892, over 350Mt of ore have been removed from Malmberget, and another 350Mt of iron reserves have been declared proven and probable. The state-owned mining company, LKAB, operates the facility. They have increased production in the past years, effectively doubling the amount of ore processed annually, between 1998 and 2013. Despite these changes, the volume of water used within the system has not grown proportionally, and is not predicted to do so in the future. This is due to increases in process-water recycling, adding to the demands placed on this water. As it is reused, the conservative and trace element concentrations grow, affecting overall water quality. Some portion of the spent process water is released on a daily basis into the nearby Lina River. This discharge is generated in two ways: (1) By means of monitored release via outlet pipes, and (2) through diffuse leakage and subsurface flow originating at the facility's tailings and settling ponds. This study aims to describe both the quality and quantity of the second form of discharge- with the ultimate goal of predicting these attributes given projected ore processing and water-recycling increases. With limited data- consisting primarily of routine water sampling- an understanding of the nature of this leakage must be gained through combined geochemical modeling and site characterization. With this objective in mind, fieldwork was conducted to quantify the volume of flow between groundwater and surface water bodies in the portion of the river adjacent to the mine. This utilized two basic hydrologic techniques: stream gaging, and the deployment of simple seepage meters. The data collected from this investigation was then used to construct a hydrologic model illustrating the proposed movement of water from the tailings and settling ponds- chronicling the path to its eventual release into the gaining river. Further coupling of the hydrologic and geochemical information will improve the accuracy of this prediction, in addition to addressing the question of water quality.

Beyond the obvious limits of ore deposits: The use of mineralogical, geochemical, and biological features for the remote detection of mineralization

USGS Publications Warehouse

Kelley, D.L.; Kelley, K.D.; Coker, W.B.; Caughlin, B.; Doherty, M.E.

2006-01-01

Far field features of ore deposits include mineralogical, geochemical, or biological attributes that can be recognized beyond the obvious limits of the deposits. They can be primary, if formed in association with mineralization or alteration processes, or secondary, if formed from the interaction of ore deposits with the hydrosphere and biosphere. This paper examines a variety of far field features of different ore deposit types and considers novel applications to exploration and discovery. Primary far field features include mineral and rock chemistry, isotopic or element halos, fluid pathways and thermal anomalies in host-rock sequences. Examples include the use of apatite chemistry to distinguish intrusive rocks permissive for iron oxide copper gold (IOCG) and porphyry deposits; resistate mineral (e.g., rutile, tourmaline) chemistry in exploration for volcanogenic massive sulfide (VMS), orogenic gold, and porphyry deposits; and pyrite chemistry to vector toward sedimentary exhalative (sedex) deposits. Distinctive whole-rock geochemical signatures also can be recognized as a far field feature of porphyry deposits. For example, unique Sr/Y ratios in whole-rock samples, used to distinguish barren versus fertile magmas for Cu mineralization, result from the differentiation of oxidized hydrous melts. Anomalous concentrations of halogen elements (Cl, Br, and I) have been found for distances of up to 200 m away from some mineralized centers. Variations in isotopic composition between ore-bearing and barren intrusions and/or systematic vertical and lateral zonation in sulfur, carbon, or oxygen isotope values have been documented for some deposit types. Owing to the thermal aureole that extends beyond the area of mineralization for some deposits, detection of paleothermal effects through methods such as conodont alteration indices, vitrinite or bitumen reflectance, illite crystallinity, and apatite or zircon thermochronology studies also can be valuable, particularly for deposits with a low-temperature thermal history. A number of newly investigated secondary far field features include the development of reduced columns by electrochemical processes in transported overburden, geochemical dispersion related to the expulsion of groundwater from tectonic and seismic compression, dispersion of vapor above ore deposits, and geochemical dispersion related to biological processes. Redox gradients have been found between underlying reduced and overlying oxidized environments associated with sulfide bodies, which result in mass transfer through electro-chemical dispersion. Recent studies have characterized the pH, oxidation-reduction potential (ORP), and self potential (SP) in overburden overlying sulfide-hosted gold and VMS deposits. Lateral migration of metals in groundwater is well understood from normal groundwater flow, but the processes responsible for vertical mass transfer of groundwater and its dissolved components have been recognized only recently. One process, termed cyclical dilatancy pumping, expels groundwater during and after earthquake events, which can cause the redistribution of metals around deposits in some environments. Soil gases are of interest owing to their high degree of mobility through the vadose zone in transported overburden. Numerous soil gas species (CO2, O2, Hg, Rn, He, sulfur compounds, and light hydrocarbons) have been measured and interpreted as diagnostic of some buried mineral deposits, and some evidence suggests a possible link between vapor dispersion and metal enrichment in soil. Geochemical enrichment in plant material and soils through successive growth-death cycles is well established, but the important role of microorganisms is now increasingly evident. Microorganisms significantly enhance the kinetics of sulfide oxidation and influence the distribution of metals around ore deposits. The presence of metal-resistant bacteria and enhanced concentrations of sulfate-reducing bacteria in exotic overburd

Potential aquifer vulnerability in regions down-gradient from uranium in situ recovery (ISR) sites.

PubMed

Saunders, James A; Pivetz, Bruce E; Voorhies, Nathan; Wilkin, Richard T

2016-12-01

Sandstone-hosted roll-front uranium ore deposits originate when U(VI) dissolved in groundwater is reduced and precipitated as insoluble U(IV) minerals. Groundwater redox geochemistry, aqueous complexation, and solute migration are important in leaching uranium from source rocks and transporting it in low concentrations to a chemical redox interface where it is deposited in an ore zone typically containing the uranium minerals uraninite, pitchblende, and/or coffinite; various iron sulfides; native selenium; clays; and calcite. In situ recovery (ISR) of uranium ores is a process of contacting the uranium mineral deposit with leaching and oxidizing (lixiviant) fluids via injection of the lixiviant into wells drilled into the subsurface aquifer that hosts uranium ore, while other extraction wells pump the dissolved uranium after dissolution of the uranium minerals. Environmental concerns during and after ISR include water quality degradation from: 1) potential excursions of leaching solutions away from the injection zone into down-gradient, underlying, or overlying aquifers; 2) potential migration of uranium and its decay products (e.g., Ra, Rn, Pb); and, 3) potential mobilization and migration of redox-sensitive trace metals (e.g., Fe, Mn, Mo, Se, V), metalloids (e.g., As), and anions (e.g., sulfate). This review describes the geochemical processes that control roll-front uranium transport and fate in groundwater systems, identifies potential aquifer vulnerabilities to ISR operations, identifies data gaps in mitigating these vulnerabilities, and discusses the hydrogeological characterization involved in developing a monitoring program. Published by Elsevier Ltd.

Results of the survey activities and mobile gamma scanning in Monticello, Utah

DOE Office of Scientific and Technical Information (OSTI.GOV)

Little, C.A.; Berven, B.A.

The town of Monticello, Utah, was once the site of an active mill which processed vanadium ore (1942 to 1948), and uranium ore (1948 to 1960). Properties in the vicinity of that mill have become contaminated with radioactive material from ore processing. The Radiological Survey Activities (RASA) group at Oak Ridge National Laboratory (ORNL) was requested by the Division of Remedial Action Projects (DRAP) in the Department of Energy (DOE) to: (1) identify potentially contaminated properties; (2) assess natural background radiation levels; and (3) rapidly assess the magnitude, extent, and type (i.e. ore, tailings, etc.) of contamination present on thesemore » properties (if any). This survey was conducted by RASA during April 1983. In addition to the 114 properties previously identified from historical information, the ORNL mobile gamma scanning van located 36 new properties exhibiting anomalous gamma radiation levels. Onsite surveys were conducted on 145 of the 150 total properties identified either historically or with the gamma scanning van. Of these 145 properties, 122 of them appeared to have some type of contaminated material present on them; however, only 48 appeared to be contaminated to the extent where they were in excess of Environmental Protection Agency (EPA) criteria (40 CFR 192). Twenty-one other properties were recommended for additional investigation (indoor gamma scanning and radon daughter measurements); of these, only ten required further analysis. This report provides the detailed data and analyses related to the radiological survey efforts performed by ORNL in Monticello, Utah.« less

Characterisation and classification of solid wastes coming from reductive acid leaching of low-grade manganiferous ore.

PubMed

De Michelis, Ida; Ferella, Francesco; Beolchini, Francesca; Olivieri, Agostino; Vegliò, Francesco

2009-03-15

The present work was focused on the acid leaching process for manganese extraction in reducing environment to low-grade manganiferous ore that comes from Central Italy. The aim of this study was to establish optimum leaching operating conditions to reduce treatment costs of waste or, even better, to allow a waste valorisation as raw materials for other applications. Consequently, the main focus of the work was the characterization and classification of the solid wastes coming from the process carried out at different operating conditions; at the same moment the effect of process parameters on Mn extraction was also analysed. The effect of particles size on the manganese extraction in reductive acid leaching process was investigated, by using lactose as reducing agent. Particle size did not show a large influence on the Mn extraction yields in the investigated process conditions. This aspect suggests the use of the leaching waste for civil and/or environmental application: use of leaching solid wastes like filling material is to be applied, for example, for environmental restoration. The classification of the solid wastes, according to the Italian Laws about Release Test (RT), has demonstrated that the solid waste produced by leaching can be classifiable as "hazardous special waste". An improvement of solid washing let to reduce the SO(4)(2-) and an appropriate treatment is necessary to reduce the dangerousness of these solids. Possible application of ore and waste as raw materials in the ceramic industry was demonstrated not to be feasible.

Effect of pulp density and particle size on indirect bioleaching of Pomalaa nickel laterite using metabolic citric acid

NASA Astrophysics Data System (ADS)

Petrus, H. B. T. M.; Wanta, K. C.; Setiawan, H.; Perdana, I.; Astuti, W.

2018-01-01

Nickel laterite ore contains oxide of iron, aluminum or both with nickel, cobalt and chromium which can be leached out using hydrometallurgical process. For the purpose of meeting the world’s increasing demand of nickel, there is a need to invent environmentally friendly process to efficiently leach nickel. This experiment used nickel laterite ore obtained from Pomalaa, South Sulawesi. The leaching agent is metabolic citric acid produced by Aspergillus niger under optimum condition. Leaching process was done in three-necked flask in atmospheric temperature and constant stirring speed of 200 rpm. The variable examined in the experiment was pulp density and particle size of nickel laterite ore. Samples were taken at 3, 7, 10, 14, and 17 minutes and then filtered and diluted to be analyzed using ICP-AES. The result of the experiment showed the maximum recovery of metals increase with the decrease of the pulp density. The maximum recovery for varying pulp density were at 5% solid/liquid ratio and the recovery were Ni at 1.63%, Al at 0.47%, Fe at 0.23% and Mg at 1.09%. The effect of particle size on leaching process showed that the leaching process follows the shrinking core model. The maximum recovery of metals at particle size were at 100-120 mesh with Ni at 1.37%, Fe at 0.10%, Al at 0.72% and Mg at 0.62%.

Recovery of Nickel and Cobalt from Laterite Tailings by Reductive Dissolution under Aerobic Conditions Using Acidithiobacillus Species.

PubMed

Marrero, J; Coto, O; Goldmann, S; Graupner, T; Schippers, A

2015-06-02

Biomining of sulfidic ores has been applied for almost five decades. However, the bioprocessing of oxide ores such as laterites lags commercially behind. Recently, the Ferredox process was proposed to treat limonitic laterite ores by means of anaerobic reductive dissolution (AnRD), which was found to be more effective than aerobic bioleaching by fungi and other bacteria. We show here that the ferric iron reduction mediated by Acidithiobacillus thiooxidans can be applied to an aerobic reductive dissolution (AeRD) of nickel laterite tailings. AeRD using a consortium of Acidithiobacillus thiooxidans and Acidithiobacillus ferrooxidans extracted similar amounts of nickel (53-57%) and cobalt (55-60%) in only 7 days as AnRD using Acidithiobacillus ferrooxidans. The economic and environmental advantages of AeRD for processing of laterite tailings comprise no requirement for an anoxic atmosphere, 1.8-fold less acid consumption than for AnRD, as well as nickel and cobalt recovered in a ferrous-based pregnant leach solution (PLS), facilitating the subsequent metal recovery. In addition, an aerobic acid regeneration stage is proposed. Therefore, AeRD process development can be considered as environmentally friendly for treating laterites with low operational costs and as an attractive alternative to AnRD.

Application of self-organizing maps to the study of U-Zr-Ti-Nb distribution in sandstone-hosted uranium ores

NASA Astrophysics Data System (ADS)

Klus, Jakub; Pořízka, Pavel; Prochazka, David; Mikysek, Petr; Novotný, Jan; Novotný, Karel; Slobodník, Marek; Kaiser, Jozef

2017-05-01

This paper presents a novel approach for processing the spectral information obtained from high-resolution elemental mapping performed by means of Laser-Induced Breakdown Spectroscopy. The proposed methodology is aimed at the description of possible elemental associations within a heterogeneous sample. High-resolution elemental mapping provides a large number of measurements. Moreover, typical laser-induced plasma spectrum consists of several thousands of spectral variables. Analysis of heterogeneous samples, where valuable information is hidden in a limited fraction of sample mass, requires special treatment. The sample under study is a sandstone-hosted uranium ore that shows irregular distribution of ore elements such as zirconium, titanium, uranium and niobium. Presented processing methodology shows the way to reduce the dimensionality of data and retain the spectral information by utilizing self-organizing maps (SOM). The spectral information from SOM is processed further to detect either simultaneous or isolated presence of elements. Conclusions suggested by SOM are in good agreement with geological studies of mineralization phases performed at the deposit. Even deeper investigation of the SOM results enables discrimination of interesting measurements and reveals new possibilities in the visualization of chemical mapping information. Suggested approach improves the description of elemental associations in mineral phases, which is crucial for the mining industry.

77 FR 130 - Notice of Intent To Prepare an Environmental Impact Statement for the Proposed Intercontinental...

Federal Register 2010, 2011, 2012, 2013, 2014

2012-01-03

... issues: Water availability; Impacts from subsidence; Impacts to oil and gas exploration and operation in... processing facilities, including the ore process plant, dry stack tailings pile, evaporation ponds, water...

Nitrile O-ring Cracking: A Case of Vacuum Flange O-ring Failures

DOE Office of Scientific and Technical Information (OSTI.GOV)

Dees, Craig

2016-07-01

A review of recent nitrile O-ring failures in ISO-KF vacuum flange connections in glovebox applications is presented. An investigation of a single “isolated” o-ring failure leads to the discovery of cracked nitrile o-rings in a glovebox atmospheric control unit. The initial cause of the o-ring failure is attributed to ozone degradation. However, additional investigation reveals nitrile o-ring cracking on multiple gloveboxes and general purpose piping, roughly 85% of the nitrile o-rings removed for inspection show evidence of visible cracking after being in service for 18 months or less. The results of material testing and ambient air testing is presented, elevatedmore » ozone levels are not found. The contributing factors of o-ring failure, including nitrile air sensitivity, inadequate storage practices, and poor installation techniques, are discussed. A discussion of nitrile o-ring material properties, the benefits and limitations, and alternate materials are discussed. Considerations for o-ring material selection, purchasing, storage, and installation are presented in the context of lessons learned from the nitrile o-ring cracking investigation. This paper can be presented in 20 minutes and does not require special accommodations or special audio visual devices.« less

Composite correlation filter for O-ring detection in stationary colored noise

NASA Astrophysics Data System (ADS)

Hassebrook, Laurence G.

2009-04-01

O-rings are regularly replaced in aircraft and if they are not replaced or if they are installed improperly, they can result in catastrophic failure of the aircraft. It is critical that the o-rings be packaged correctly to avoid mistakes made by technicians during routine maintenance. For this reason, fines may be imposed on the o-ring manufacturer if the o-rings are packaged incorrectly. That is, a single o-ring must be packaged and labeled properly. No o-rings or more than one o-ring per package is not acceptable. We present an industrial inspection system based on real-time composite correlation filtering that has successfully solved this problem in spite of opaque paper o-ring packages. We present the system design including the composite filter design.

Impact of Alternative Processes for Aluminum Production on Energy Requirements

NASA Astrophysics Data System (ADS)

Grjotheim, Kai; Welch, Barry

1981-09-01

Increasing prices and the shortage of large blocks of electrical energy have given greater impetus to the search for viable alternative processes for aluminum production. These include electrolysis of aluminum chloride, sulfide, and nitride; carbothermal reduction of either the ore or alumina; and disproportioning reactions of either aluminum sulfide or the monochloride route. Common to all these processes are the starting material—an ore containing aluminum oxide—and the final product—the metal. Thus, the thermodynamic cycle will invariably dictate similar theoretical energy requirements for the three processes. In practice, however, the achievable efficiencies and, more noticeably, the proportion of electrical to carbothermal energy required for the various stages of operation can vary. The present status of these alternative processes indicates that while alternative routes, such as the Alcoa-AlCl3-Smelting Process, show distinct potential for reducing electrical energy requirements, they offer little chance of reducing overall energy requirements. Furthermore, because of more stringent purity requirements, any gains made may be at the expense of production costs.

Ore-fluid evolution at the Getchell Carlin-type gold deposit, Nevada, USA

USGS Publications Warehouse

Cline, J.S.; Hofstra, A.A.

2000-01-01

Minerals and fluid-inclusion populations were examined using petrography, microthermometry, quadrupole mass-spectrometer gas analyses and stable-isotope studies to characterize fluids responsible for gold mineralization at the Getchell Carlin-type gold deposit. The gold-ore assemblage at Getchell is superimposed on quartz-pyrite vein mineralization associated with a Late-Cretaceous granodiorite stock that intruded Lower-Paleozoic sedimentary rocks. The ore assemblage, of mid-Tertiary age, consists of disseminated arsenian pyrite that contains submicrometer gold, jasperoid quartz, and later fluorite and orpiment that fill fractures and vugs. Late ore-stage realgar and calcite enclose ore-stage minerals. Pre-ore quartz trapped fluids with a wide range of salinities (1 to 21 wt.% NaCl equivalent), gas compositions (H2O, CO2, and CH4), and temperatures (120 to >360??C). Oxygen- and hydrogen-isotope ratios indicate that pre-ore fluids likely had a magmatic source, and were associated with intrusion of the granodiorite stock and related dikes. Ore-stage jasperoid contains moderate salinity, aqueous fluid inclusions trapped at 180 to 220??C. Ore fluids contain minor CO2 and trace H2S that allowed the fluid to react with limestone host rocks and transport gold, respectively. Aqueous inclusions in fluorite indicate that fluid temperatures declined to ~175??C by the end of ore-stage mineralization. As the hydrothermal system collapsed, fluid temperatures declined to 155 to 115??C and realgar and calcite precipitated. Inclusion fluids in ore-stage minerals have high ??D(H2O) and ??18O(H2O) values that indicate that the fluid had a deep source, and had a metamorphic or magmatic origin, or both. Late ore-stage fluids extend to lower ??D(H2O) values, and have a wider range of ??18O(H2O) values suggesting dilution by variably exchanged meteoric waters. Results show that deeply sourced ore fluids rose along the Getchell fault system, where they dissolved carbonate wall rocks and deposited gold-enriched pyrite and jasperoid quartz. Gold and pyrite precipitated together as H2S in the ore fluids reacted with iron in the host rocks. As ore fluids mixed with local aquifer fluids, ore fluids became cooler and more dilute. Cooling caused precipitation of ore-stage fluorite and orpiment, and late ore-stage realgar. Phase separation and/or neutralization of the ore fluid during the waning stages of the hydrothermal ore system led to deposition of late ore-stage calcite.

Formation of Si-Al-Mg-Ca-rich zoned magnetite in an end-Permian phreatomagmatic pipe in the Tunguska Basin, East Siberia

NASA Astrophysics Data System (ADS)

Neumann, Else-Ragnhild; Svensen, Henrik H.; Polozov, Alexander G.; Hammer, Øyvind

2017-12-01

Magma-sediment interactions in the evaporite-rich Tunguska Basin resulted in the formation of numerous phreatomagmatic pipes during emplacement of the Siberian Traps. The pipes contain magnetite-apatite deposits with copper and celestine mineralization. We have performed a detailed petrographic and geochemical study of magnetite from long cores drilled through three pipe breccia structures near Bratsk, East Siberia. The magnetite samples are zoned and rich in Si (≤5.3 wt% SiO2), Ca, Al, and Mg. They exhibit four textural types: (1) massive ore in veins, (2) coating on breccia clasts, (3) replacement ore, and (4) reworked ore at the crater base. The textural types have different chemical characteristics. "Breccia coating" magnetite has relatively low Mg content relative to Si, as compared to the other groups, and appears to have formed at lower oxygen fugacity. Time series analyses of MgO variations in microprobe transects across Si-bearing magnetite in massive ore indicate that oscillatory zoning in the massive ore was controlled by an internal self-organized process. We suggest that hydrothermal Fe-rich brines were supplied from basalt-sediment interaction zones in the evaporite-rich sedimentary basin, leading to magnetite ore deposition in the pipes. Hydrothermal fluid composition appears to be controlled by proximity to dolerite fragments, temperature, and oxygen fugacity. Magnetite from the pipes has attributes of iron oxide-apatite deposits (e.g., textures, oscillatory zoning, association with apatite, and high Si content) but has higher Mg and Ca content and different mineral assemblages. These features are similar to magnetite found in skarn deposits. We conclude that the Siberian Traps-related pipe magnetite deposit gives insight into the metamorphic and hydrothermal effects following magma emplacement in a sedimentary basin.

Metamorphic ore remobilization in the Hällefors district, Bergslagen, Sweden: constraints from mineralogical and small-scale sulphur isotope studies

NASA Astrophysics Data System (ADS)

Wagner, Thomas; Jonsson, Erik; Boyce, Adrian J.

2005-07-01

The marble- and metavolcanic-hosted Pb Zn (Ag Sb As) deposits of the Hällefors district, located in the Palaeoproterozoic Bergslagen ore province, south central Sweden, comprise both stratabound sulphides and discordant, Ag-rich sulphide sulphosalt veins. The complex sulphide sulphosalt assemblages of the Alfrida-Jan Olof mines at Hällefors were investigated by a combination of ore microscopy, electron-microprobe analysis, and in situ laser sulphur isotope analysis. The massive ore is characterized by positive and homogeneous δ34S (+1.4‰ to +2.7‰ V-CDT), whereas vein-hosted sulphides and sulphosalts exhibit similar, but generally less positive to slightly negative δ34S (-0.6‰ to +2.0‰). Comparison of the observed ore mineral assemblages with calculated phase equilibria in the system Fe As S O H and isotopic fractionation as a function of temperature, oxygen fugacity and pH indicates that the vein-type mineralization was formed from relatively reduced and rather alkaline hydrothermal fluids. At these reduced conditions, fractionation of δ34S via changes of fO2 is insignificant, and thus the isotopic signatures of the vein minerals directly reflect the composition of the sulphur source. We therefore conclude that the vein-type ore essentially inherited the sulphur isotope signature from the pre-existing massive sulphides via metamorphic remobilization at approximately 300 400°C and 2 3 kbar. Scales of remobilization observable are on the order of about 5 mm to 30 cm. Overall, the sulphide sulphosalt assemblages from the Alfrida-Jan Olof mines exhibit δ34S values which are comparable to a majority of metasupracrustal-hosted deposits in the Bergslagen province, thereby suggesting a common origin from ca. 1.90 1.88 Ga volcanic-hydrothermal processes.

A cultural setting where the other-race effect on face recognition has no social-motivational component and derives entirely from lifetime perceptual experience.

PubMed

Wan, Lulu; Crookes, Kate; Reynolds, Katherine J; Irons, Jessica L; McKone, Elinor

2015-11-01

Competing approaches to the other-race effect (ORE) see its primary cause as either a lack of motivation to individuate social outgroup members, or a lack of perceptual experience with other-race faces. Here, we argue that the evidence supporting the social-motivational approach derives from a particular cultural setting: a high socio-economic status group (typically US Whites) looking at the faces of a lower status group (US Blacks) with whom observers typically have at least moderate perceptual experience. In contrast, we test motivation-to-individuate instructions across five studies covering an extremely wide range of perceptual experience, in a cultural setting of more equal socio-economic status, namely Asian and Caucasian participants (N = 480) tested on Asian and Caucasian faces. We find no social-motivational component at all to the ORE, specifically: no reduction in the ORE with motivation instructions, including for novel images of the faces, and at all experience levels; no increase in correlation between own- and other-race face recognition, implying no increase in shared processes; and greater (not the predicted less) effort applied to distinguishing other-race faces than own-race faces under normal ("no instructions") conditions. Instead, the ORE was predicted by level of contact with the other-race. Our results reject both pure social-motivational theories and also the recent Categorization-Individuation model of Hugenberg, Young, Bernstein, and Sacco (2010). We propose a new dual-route approach to the ORE, in which there are two causes of the ORE-lack of motivation, and lack of experience--that contribute differently across varying world locations and cultural settings. Copyright © 2015 Elsevier B.V. All rights reserved.

Genesis of Middle Miocene Yellowstone hotspot-related bonanza epithermal Au-Ag deposits, Northern Great Basin, USA

NASA Astrophysics Data System (ADS)

Saunders, J. A.; Unger, D. L.; Kamenov, G. D.; Fayek, M.; Hames, W. E.; Utterback, W. C.

2008-09-01

Epithermal deposits with bonanza Au-Ag veins in the northern Great Basin (NGB) are spatially and temporally associated with Middle Miocene bimodal volcanism that was related to a mantle plume that has now migrated to the Yellowstone National Park area. The Au-Ag deposits formed between 16.5 and 14 Ma, but exhibit different mineralogical compositions, the latter due to the nature of the country rocks hosting the deposits. Where host rocks were primarily of meta-sedimentary or granitic origin, adularia-rich gold mineralization formed. Where glassy rhyolitic country rocks host veins, colloidal silica textures and precious metal-colloid aggregation textures resulted. Where basalts are the country rocks, clay-rich mineralization (with silica minerals, adularia, and carbonate) developed. Oxygen isotope data from quartz (originally amorphous silica and gels) from super-high-grade banded ores from the Sleeper deposit show that ore-forming solutions had δ 18O values up to 10‰ heavier than mid-Miocene meteoric water. The geochemical signature of the ores (including their Se-rich nature) is interpreted here to reflect a mantle source for the “epithermal suite” elements (Au, Ag, Se, Te, As, Sb, Hg) and that signature is preserved to shallow crustal levels because of the similar volatility and aqueous geochemical behavior of the “epithermal suite” elements. A mantle source for the gold in the deposits is further supported by the Pb isotopic signature of the gold ores. Apparently the host rocks control the mineralization style and gangue mineralogy of ores. However, all deposits are considered to have derived precious metals and metalloids from mafic magmas related to the initial emergence of the Yellowstone hotspot. Basalt-derived volatiles and metal(loid)s are inferred to have been absorbed by meteoric-water-dominated geothermal systems heated by shallow rhyolitic magma chambers. Episodic discharge of volatiles and metal(loid)s from deep basaltic magmas mixed with heated meteoric water to create precious metal ore-forming fluids. Colloidal nanoparticles of Au-Ag alloy (electrum), naumannite (Ag2Se), silica, and adularia, likely nucleated at depth, traveled upward, and deposited where they grew large enough to aggregate along vein walls. Silica and gold colloids have been reported in hot springs from Yellowstone National Park, suggesting that such processes may continue to some extent to the present. However, it is possible that the initial development of the mantle plume led to a major but short-lived “distillation” process which led to the mid-Miocene bonanza ore-forming event.

Manganese and ferromanganese ores from different tectonic settings in the NW Himalayas, Pakistan

NASA Astrophysics Data System (ADS)

Tahir Shah, Mohammad; Moon, Charles J.

2007-02-01

In Pakistan manganese and ferromanganese ores have been reported from the Hazara area of North West Frontier Province, Waziristan agencies in the Federally Administered Tribal Areas and the Lasbela-Khuzdar regions of Baluchistan. This study is focused on comparison of mineralogy and geochemistry of the continental ferromanganese ores of Hazara and the ophiolitic manganese ores of the Waziristan area of Pakistan. In the Hazara area, ferromanganese ores occur at Kakul, Galdanian and Chura Gali, near Abbottabad, within the Hazira Formation of the Kalachitta-Margala thrust belt of the NW Himalayas of the Indo-Pakistan Plate. The Cambrian Hazira Formation is composed of reddish-brown ferruginous siltstone, with variable amounts of clay, shale, ferromanganese ores, phosphorite and barite. In Waziristan, manganese ores occur at Shuidar, Mohammad Khel and Saidgi, within the Waziristan ophiolite complex, on the western margin of the Indo-Pakistan Plate in NW Pakistan. These banded and massive ores are hosted by metachert and overlie metavolcanics. The ferromanganese ores of the Hazara area contain variable amount of bixbyite, partridgeite, hollandite, pyrolusite and braunite. Bixbyite and partridgeite are the dominant Mn-bearing phases. Hematite dominates in Fe-rich ores. Gangue minerals are iron-rich clay, alumino-phosphate minerals, apatite, barite and glauconite are present in variable amounts, in both Fe-rich and Mn-rich varieties. The texture of the ore phases indicates greenschist facies metamorphism. The Waziristan ores are composed of braunite, with minor pyrolusite and hollandite. Hematite occurs as an additional minor phase in the Fe-rich ores of the Shuidar area. The only silicate phase in these ores is cryptocrystalline quartz. The chemical composition of the ferromanganese ores in Hazara suggests that the Mn-Fe was contributed by both hydrogenous and hydrothermal sources, while the manganese ores of Waziristan originated only from a hydrothermal source. It is suggested that the Fe-Mn ores of the Hazara area originated from a mixed hydrothermal-hydrogenetic source in shallow water in a ontinental shelf environment due to the transgression and regression of the sea, while the Mn ores of Waziristan were formed at sea-floor spreading centers within the Neo-Tethys Ocean, and were later obducted as part of the Waziristan ophiolite complex.

A preliminary study on the reduction of limonite ore by using rice husk as a reducing agent

NASA Astrophysics Data System (ADS)

Maksum, Ahmad; Husein, Michael Kelvin E.; Permana, Sulaksana; Rustandi, Andi; Wahyuadi Soedarsono, Johny

2018-03-01

The abundant of rice husk in Indonesia has encouraged researchers to study the feasibility of rice husk for substituting material that is more expensive or dangerous. In previous study, silica with a purity of 99.9% has been obtained from rice husk with calcinations process. Nevertheless, the gases resulting from the process were not used and left useless. Therefore, in this study, those gases derived from rice husk calcinations process were used as reducing agents during the ferronickel (Fe-Ni) production through a direct reduction process. The objective of this study was to investigate the effect of the amount of rice husk in the pellets on the increase of nickel content in the limonite reduction process. The limonite ore were crushed to the size of less than 150 mesh using disc-mill, and then were mixed with rice husk powder (10, 20, 30 in wt % mass) before being pelletized using bentonite as a binder. The resulted pellets were roasted at 500°C for 60 minutes and then quenched in water media. After drying process, the reduction process of 40g pellets was conducted at 1000°C for 90 minutes with 20g rice husk in furnace. The effects of additional rice husk on the direct reduction of limonite ore pellets were qualitatively analyzed by using X-ray powder diffraction (XRD) and quantitatively by Atomic absorption spectroscopy (AAS). Both analysis results showed that the reduction process followed the reaction scheme: Fe2O3→Fe3O4→FeO and NiO phase was detected in the sample with 20% rice husk addition. The optimum concentration of Ni 1.23% was obtained for 20% rice husk addition.

High-rate behaviour of iron ore pellet

NASA Astrophysics Data System (ADS)

Gustafsson, Gustaf; Häggblad, Hans-Åke; Jonsén, Pär; Nishida, Masahiro

2015-09-01

Iron ore pellets are sintered, centimetre-sized spheres of ore with high iron content. Together with carbonized coal, iron ore pellets are used in the production of steel. In the transportation from the pelletizing plants to the customers, the iron ore pellets are exposed to different loading situations, resulting in degradation of strength and in some cases fragmentation. For future reliable numerical simulations of the handling and transportation of iron ore pellets, knowledge about their mechanical properties is needed. This paper describes the experimental work to investigate the dynamic mechanical properties of blast furnace iron ore pellets. To study the dynamic fracture of iron ore pellets a number of split Hopkinson pressure bar tests are carried out and analysed.

Physiological effects of an additional stressor on fish exposed to a simulated heavy-metal-containing effluent from a sulfide ore smeltery

DOE Office of Scientific and Technical Information (OSTI.GOV)

Larsson, A.; Haux, C.; Sjoebeck, M.L.

1984-04-01

Perches (Perca fluviatilis), kept in slightly hypotonic brackish water, were exposed to dilutions of a simulated heavy-metal-containing effluent from a sulfide ore smeltery . Biochemical and hematological effects of the effluent, as well as the metal residues in liver and muscle tissues, were investigated after 12 and 27 days of exposure. The metal analyses revealed no significant uptake of metals in liver and muscle during the experiment. In spite of this, the exposed fish showed several physiological effects. Some of these, e.g., anemia, hypocalcemia, increased muscle water content, and reduced liver size, were of a transient nature, while others, suchmore » as disturbed chloride balance and hyperglycemia, seemed to be more persistent. At the end of the experiment (29-33 days of exposure), the physiological response to stress treatment (asphyxia) and a subsequent recovery were studied in exposed and unexposed fish. This stress investigation indicates that an additional stressor may strengthen the toxic effects of the heavy-metal-containing effluent. Furthermore, the secondary stress responses were more pronounced and the ability to recover from them seemed to be impaired in exposed fish as compared to unexposed fish.« less

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... mercury ore subcategory. 440.40 Section 440.40 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The provisions...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... ore subcategory. 440.10 Section 440.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.10 - Applicability; description of the iron ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... ore subcategory. 440.10 Section 440.10 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions of...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... tungsten ore subcategory. 440.60 Section 440.60 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60 Applicability; description of the tungsten ore subcategory. The...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The...

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... antimony ore subcategory. 440.90 Section 440.90 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90 Applicability; description of the antimony ore subcategory. The...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... nickel ore subcategory. 440.70 Section 440.70 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The provisions...

40 CFR 440.50 - Applicability; description of the titanium ore subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... titanium ore subcategory. 440.50 Section 440.50 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY (CONTINUED) EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Titanium Ore Subcategory § 440.50 Applicability; description of the titanium ore subcategory. The...