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1

MATHEMATICAL MODELLING AND OPTIMISATION OF IRON ORE SINTER PROPERTIES  

Microsoft Academic Search

The quality of iron ore sinter is a critical factor determining the productivity of blast furnaces for ironmaking. Csiro has therefore been developing capabilities for predicting sinter characteristics, which enables sinter quality to be improved\\/optimized and preliminary assessments to be made of the suitability of specific ores or ore blends for sinter production. An extensive database of pilot-scale sintering experimental

E. Donskoi; J. R. Manuel; J. M. F. Clout; Y. Zhang

2

Atmospheric emission of polychlorinated naphthalenes from iron ore sintering processes.  

PubMed

Iron ore sintering processes constitute significant sources of dioxins, and studies have confirmed a close correlation between polychlorinated naphthalenes (PCNs) and dioxin formation. Thus, iron ore sintering processes are thought to be a potential source of PCNs, although intensive investigations on PCN emissions from sintering processes have not been carried out. Therefore, the aim of the present study was to qualify and quantify PCN emissions from nine sintering plants operating on different industrial scales. PCN concentrations ranged from 3 to 983 ng m(-3) (0.4-23.3 pg TEQ(PCN) m(-3)) and emission factors ranged from 14 to 1749 ?g t(-1) (0.5-41.5 ng TEQ(PCN) t(-1)), with a geometric mean of 84 ?g t(-1) (2.1 ng TEQ(PCN) t(-1)). The estimated annual emission of PCNs from sintering processes in China was 1390 mg TEQ(PCN). These figures will assist in the development of a PCN emissions inventory. Regarding emission characteristics, PCNs mainly comprised low-chlorinated homologs. The ratios of several characteristic PCN congeners were also measured and compared with those from other sources. Taken together, these results may provide useful information for identifying the sources of PCNs produced by iron ore sintering processes. PMID:22739541

Liu, Guorui; Zheng, Minghui; Du, Bing; Nie, Zhiqiang; Zhang, Bing; Liu, Wenbin; Li, Cheng; Hu, Jicheng

2012-06-25

3

Combustion characteristics in an iron ore sintering bedevaluation of fuel substitution  

Microsoft Academic Search

In an iron ore sintering bed, combustion of solid fuel supplies heat needed for sintering of fine particles and determines the quality of the sintered ores and the productivity of the process. Coke has been widely used as an ideal fuel for this process, but recent attempts to partially replace coke with a less expensive fuel have been considered effective

Won Yang; Sangmin Choi; Eung Soo Choi; Deog Won Ri; Sungman Kim

2006-01-01

4

The study of sunflower seed husks as a fuel in the iron ore sintering process  

Microsoft Academic Search

An investigation was carried out into the use of sunflower seed husks as a supplementary fuel in the iron ore sintering process. Fuel blends were prepared by mixing different amounts of sunflower seed husks and coke in order to produce the same heat output as 5% coke breeze. Sinter pot experiments with fuels containing different amounts of sunflower seed husks

Tze Chean Ooi; Eric Aries; Bruce C. R. Ewan; Dennis Thompson; David R. Anderson; Ray Fisher; Trevor Fray; Donna Tognarelli

2008-01-01

5

Polycyclic Aromatic Hydrocarbon Emission Profiles and Removal Efficiency by Electrostatic Precipitator and Wetfine Scrubber in an Iron Ore Sintering Plant  

Microsoft Academic Search

A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants,

Ettore Guerriero; Antonina Lutri; Rosanna Mabilia; Maria Concetta Tomasi Scian; Mauro Rotatori; Mark Trexler; Russell Sawvel; Byung Kim; Pedro Alvarez; Zhiling Gao; Raymond Desjardins; Ronald Haarlem; Thomas Flesch; Hualiang Teng; Valerian Kwigizile; Moses Karakouzian; David James; Vic Etyemezian; Gang Sun; Huiqing Guo; Jonathan Peterson; Bernardo Predicala; Claude Lague; Yungang Wang; Yifang Zhu; Robert Salinas; David Ramirez; Saritha Karnae; Kuruvilla John; Sang-Sup Lee; Joo-Youp Lee; Tim Keener; Alexandra Tsimpidi; Vlassis Karydis; Spyros Pandis; David MacIntosh; Theodore Myatt; Jerry Ludwig; Brian Baker; Helen Suh; John Spengler; Jung-Hun Woo; Shan He; Efthimios Tagaris; Kuo-Jen Liao; Kasemsan Manomaiphiboon; Praveen Amar; Armistead Russell; Mae Gustin; Mei Xin; Jody Ericksen; George Fernandez

2008-01-01

6

Reducing PAH emissions from the iron ore sintering process by optimizing its operation parameters.  

PubMed

This study set out to reduce polycyclic aromatic hydrocarbon (PAH) emissions from the iron ore sintering process by optimizing its operation parameters obtained from the Taguchi experimental design. Four operating parameters, including the water content (Wc; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (HL; including sinter, hematite, and limonite) were selected and conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. We found that the resultant optimal combination (Wc = 6.5 wt %, Hb = 600 mm, Ps = 1400 mmH2O, and HL = limonite) could reduce the emission factor of total BaP equivalent concentration (EF(BaPeq)) up to 57.6% in comparison with the current operating condition of a real-scale sinter plant (Wc = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH2O, and HL = sinter). Through the ANOVA analysis, we found that Ps and Hb were the top two parameters affecting total EF(BaPeq) (accounting, respectively, for 70.9% and 21.2% of the total contribution of the four selected parameters). By examining both the sinter productivity and sinter strength, the values obtained from the optimal combination were quite comparable to those of the current operating condition. The above results further confirm the applicability of the obtained optimal combination for the real-scale sinter plant. PMID:19603662

Chen, Yu-Cheng; Tsai, Perng-Jy; Mou, Jin-Luh

2009-06-15

7

Complexometric determination of aluminium in iron ore, sinter, concentrates and agglomerates.  

PubMed

A method for the complexometric determination of aluminium in iron ore, sinter, concentrates and agglomerates encountered in international trade is described. The sample is fused in a zirconium crucible with a mixed flux of sodium carbonate and sodium peroxide. The fused mass is completely soluble in hydrochloric acid. The R(2)O(3) oxides are then precipitated with ammonia and redissolved in hydrochloric acid. Elements such as iron, titanium and zirconium are separated from aluminium by solvent extraction with cupferron and chloroform. After removal of traces of organic matter from the aqueous phase, the solution is treated with an excess of EDTA, which is then back-titrated with zinc solution (Xylenol Orange as indicator). Addition of ammonium fluoride then releases EDTA equivalent to the aluminium and this is titrated with zinc solution. The method is rapid. The precision and accuracy are excellent, and the results comparable with those obtained by the referee method. PMID:18962398

Bhargava, O P

1979-02-01

8

Formation and mitigation of PCDD/Fs in iron ore sintering.  

PubMed

The sintering of iron ore is presently a significant industrial source of polychlorinated dibenzo-p-dioxins and polychlorinated dibenzofurans (PCDD/Fs) worldwide owing to the fundamental requirement of the operation of a high temperature process to pre-treat fines and to recycle plant by-products arising from the integrated iron and steelworks. The process is a noteworthy contributor of PCDD/F indirectly due to decreasing PCDD/F releases from municipal solid waste incineration. Commonly PCDD/F formation from the process is associated with the addition of oily mill scales although raw material containing a combination of C, Cl and specific metal catalyst has been shown to drastically increase PCDD/F formation in the process. The degenerate graphitic structure of carbon present in coke fuel and soot formed and the chemistry of catalytic metals and Cl are important factors. A review on PCDD/F emission in this process has been carried out, including examination of its formation mechanism, congener distribution, contributing factors and mitigation strategies, with emphasis on the use of inhibiting compound to achieve suppression. A detailed analysis of the de novo and precursor theories of formation and the contributing factor is given since the subject of PCDD/F formation is still controversial. The de novo formation pathway identified in sinter plants and controlled studies performed in the laboratory as well as at pilot-scale are discussed; where appropriate, a comparison is drawn between sintering and other thermal processes emitting PCDD/Fs. Summary of the latest developments in PCDD/F downstream abatement strategies presently employed in full scale industrial plants is provided. Potential inhibiting compounds are discussed in terms of their mode of action and merits under sintering conditions. PMID:21880347

Ooi, Tze Chean; Lu, Liming

2011-08-30

9

Sintering Characteristics of Indian Chrome Ore Fines  

NASA Astrophysics Data System (ADS)

Chrome ore concentrate consists of high-temperature melting oxides such as Cr2O3, MgO, and Al2O3. The presence of these refractory constituents makes the ore a very high melting mineral. Hence, it is difficult to produce sinter from chrome ore by a pyrometallurgical route. Currently, chrome ore is ground to below 75 ?m, pelletized, heat hardened through carbothermic reaction at 1300 C to 1400 C, and then charged into a submerged electric arc furnace (EAF), along with lumpy ore for ferrochrome/charge-chrome production. Electricity is a major cost element in this extraction process. This work explores the sinterability of chrome ore. The objective of this study was to: (1) determine whether chrome ore is sinterable and, if so, (2) ascertain ways of achieving satisfactory properties at a low temperature of sintering. Sintering of the raw material feed could be a way to reduce electricity consumption, because during sintering a partial reduction of minerals is expected along with agglomeration. Studies carried out by the authors show that it is possible to agglomerate chrome ore fines through sintering. The chrome ore sinter thus produced was found to be inferior in strength, comparable to that of an iron ore sinter, but strength requirements may not be the same for both. Because the heat generation during chrome ore sintering is high owing to some exothermic reactions, compared with iron ore, and because chrome ore contains a high amount of fines, shallow-bed-depth sinter cake production was attempted in the laboratory-scale pot-sintering machine. The sintered product was found to be a good conductor of electricity because of the presence of phases such as magnetite and maghemite. This characteristic of the chrome ore sinter will subsequently have a favorable impact in terms of power consumption during the production of ferrochrome in a submerged EAF. The sinter made was melted in the arc furnace and it was found that the specific melting energy is comparable to that of heat-hardened chrome ore pellets but lower than briquettes and lump ore.

Nandy, Bikash; Chaudhury, Manoj Kumar; Paul, Jagannath; Bhattacharjee, D.

2009-10-01

10

PCDD/F and "Dioxin-like" PCB emissions from iron ore sintering plants in the UK.  

PubMed

Investigations have been carried out at the three Corus UK sinter plants over the period 2002-2004 to characterise the emissions of both 2,3,7,8-PCDD/Fs and WHO-12 PCBs, to estimate annual mass releases of these organic micro-pollutants using the I-TEF and WHO-TEF schemes, and to investigate the formation of PCBs in the iron ore sintering process. Results showed that the sintering of iron ore produces a characteristic WHO-12 PCB and PCDD/F congener pattern that is substantially the same for all UK sinter plants. With regard to WHO-12 PCBs, the most abundant congeners were typically PCBs 118 (6-9 ngNm(-3)), 105 (2-4 ngNm(-3)) and 77 (2-3 ngNm(-3)). All other WHO-12 PCBs were also detected at concentrations around 1 ngNm(-3). All sinter plants investigated exhibited very similar TEQ concentrations. WHO-12 PCB emissions were in the range 0.042-0.111 ngWHO-TEQNm(-3), whereas PCDD/F emissions ranged from 0.39 to 1.62 ngWHO-TEQNm(-3). PCDF congeners were the main contributors to the overall TEQ in sintering emissions (ca. 85%). Amongst WHO-12 PCBs, PCB 126 was the only noteworthy contributor to total TEQ (ca. 5-7%), a similar contribution to that from PCDDs. Based on the measurements that Corus UK has undertaken at these three sinter plants, annual mass releases of WHO-12 PCBs and PCDD/Fs have been calculated. For UK sinter plants, a total mass release of 29.5 g WHO-TEQ per annum [WHO-12 PCBs+PCDD/Fs] has been estimated, representing 9% of the total PCDD/F emissions to the UK atmosphere. Measurements were also carried out at a UK sinter plant to determine the windleg emission profile of WHO-12 PCBs. Results showed that WHO-12 PCBs were formed in the same regions of the sinter strand as 2,3,7,8-PCDD/Fs, indicating that there was a strong correlation between the formation of WHO-12 PCBs and PCDD/Fs in the iron ore sintering process. PMID:16765418

Aries, Eric; Anderson, David R; Fisher, Raymond; Fray, Trevor A T; Hemfrey, Derek

2006-06-12

11

Emission characterization of unintentionally produced persistent organic pollutants from iron ore sintering process in China.  

PubMed

Emission of unintentionally produced persistent organic pollutants (Unintentional POPs), including polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), polychorinated biphenyls (PCBs), hexachlorobenzene (HxCBz) and pentachlorobenzene (PeCBz), were investigated in four typical iron ore sintering plants in China. The emission factors and annual mass releases of the Unintentional POPs were calculated. The results indicated that PCDFs contributed more than 60% to the overall toxic equivalent quantity (TEQ) values, while the contribution of the dl-PCBs is relatively low, and only in the range of 8-9%. The dominant congeners of PCDD/Fs and dl-PCBs contributing most to the total TEQ were 1,2,3,7,8-PeCDD, 2,3,4,7,8-PeCDF and PCB-126. With regard to the TEQ contributions, the most abundant homologues were PeCDFs and HxCDD/Fs, followed by PeCDDs and non-ortho dl-PCB, whereas HpCDD/Fs, OCDD/Fs and mono-ortho dl-PCBs almost made no contributions. Due to the massive use of recycled waste in the feeding materials, the average emission factor of PCDD/Fs and dl-PCBs of the four plants was 3.95 ?g WHO-TEQ ton(-1). Based on the results, the annual release of PCDD/Fs and dl-PCBs in 2007-2009 were estimated to be 2070 g, 2212 g, and 2307 gWHO-TEQ, respectively. PMID:22727897

Tian, Bo; Huang, Jun; Wang, Bin; Deng, Shubo; Yu, Gang

2012-06-22

12

Mechanisms in oxidation and sintering of magnetite iron ore green pellets  

Microsoft Academic Search

Thermal volume changes and oxidation mechanisms in magnetite iron ore green pellets balled with 0.5% bentonite binder, as a function of raw material fineness and pellet porosity, are shown. When a pellet starts to oxidize, a shell of hematite is formed around the pellet while the core still is magnetite. Dilatation curves were measured under non-oxidizing and oxidizing atmospheres to

S. P. E. Forsmo; P.-O. Samskog; B. M. T. Bjrkman

2008-01-01

13

Comparative analysis of the mineralogical composition and metallurgical properties of sinters obtained from iron-ore-bearing charges of different origins  

Microsoft Academic Search

A study is made to determine how the main genetic groups of iron-ore-bearing components in the sintering charges used at the\\u000a MMK affect the sintering operation and the quality of the finished product (shallow bed and a complex multi-component charge).\\u000a Recommendations are presented for improving efficiency in the production of low-basicity (1.6 0.1) sinter in a shallow (260\\u000a mm high)

N. R. Mansurova; T. Ya. Malysheva; V. V. Korovushkin; M. F. Gibadulin; V. P. Lekin; V. A. Gostenin

2006-01-01

14

Polycyclic aromatic hydrocarbon emission profiles and removal efficiency by electrostatic precipitator and wetfine scrubber in an iron ore sintering plant  

SciTech Connect

A monitoring campaign of polychlorinated dibenzo-p-dioxins and dibenzofurans, polyaromatic hydrocarbons (PAHs), and polychlorinated biphenyl was carried out in an Italian iron ore sintering plant by sampling the combustion gases at the electrostatic precipitator (ESP) outlet, at the Wetfine scrubber (WS) outlet, and by collecting the ESP dust. Few data are available on these micropollutants produced in iron ore sintering plants, particularly from Italian plants. This study investigates the PAH emission profiles and the removal efficiency of ESPs and WS. PAHs were determined at the stack, ESP outlet flue gases, and in ESP dust to characterize the emission profiles and the performance of the ESP and the WS for reducing PAH emission. The 11 PAHs monitored are listed in the Italian legislative decree 152/2006. The mean total PAH sum concentration in the stack flue gases is 3.96 {mu}g/N m{sup 3}, in ESP outlet flue gases is 9.73 {mu}g/N m{sup 3}, and in ESP dust is 0.53 {mu}g/g. Regarding the emission profiles, the most abundant compound is benzo(b)fluoranthene, which has a relative low BaP toxic equivalency factors (TEF) value, followed by dibenzo(a,l)pyrene, which has a very high BaP(TEF) value. The emission profiles in ESP dust and in the flue gases after the ESP show some changes, whereas the fingerprint in ESP and stack flue gases is very similar. The removal efficiency of the ESP and of WS on the total PAH concentration is 5.2 and 59.5%, respectively. 2 figs., 5 tabs.

Ettore Guerriero; Antonina Lutri; Rosanna Mabilia; Maria Concetta Tomasi Sciano; Mauro Rotatori [Istituto sull'Inquinamento Atmosferico, Monterotondo Scalo (Italy). Consiglio Nazionale delle Ricerche

2008-11-15

15

Determining optimal operation parameters for reducing PCDD/F emissions (I-TEQ values) from the iron ore sintering process by using the Taguchi experimental design.  

PubMed

This study is the first one using the Taguchi experimental design to identify the optimal operating condition for reducing polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/ Fs) formations during the iron ore sintering process. Four operating parameters, including the water content (Wc; range = 6.0-7.0 wt %), suction pressure (Ps; range = 1000-1400 mmH2O), bed height (Hb; range = 500-600 mm), and type of hearth layer (including sinter, hematite, and limonite), were selected for conducting experiments in a pilot scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant We found that the resultant optimal combination (Wc = 6.5 wt%, Hb = 500 mm, Ps = 1000 mmH2O, and hearth layer = hematite) could decrease the emission factor of total PCDD/Fs (total EF(PCDD/Fs)) up to 62.8% by reference to the current operating condition of the real-scale sinter plant (Wc = 6.5 wt %, Hb = 550 mm, Ps = 1200 mmH2O, and hearth layer = sinter). Through the ANOVA analysis, we found that Wc was the most significant parameter in determining total EF(PCDD/Fs (accounting for 74.7% of the total contribution of the four selected parameters). The resultant optimal combination could also enhance slightly in both sinter productivity and sinter strength (30.3 t/m2/day and 72.4%, respectively) by reference to those obtained from the reference operating condition (29.9 t/m (2)/day and 72.2%, respectively). The above results further ensure the applicability of the obtained optimal combination for the real-scale sinter production without interfering its sinter productivity and sinter strength. PMID:18754384

Chen, Yu-Cheng; Tsai, Perng-Jy; Mou, Jin-Luh

2008-07-15

16

Silico-ferrite of Calcium and Aluminum (SFCA) Iron Ore Sinter Bonding Phases: New Insights into Their Formation During Heating and Cooling  

NASA Astrophysics Data System (ADS)

The formation of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter phases during heating and cooling of synthetic iron ore sinter mixtures in the range 298 K to 1623 K (25 C to 1350 C) and at oxygen partial pressure of 5 10-3 atm has been characterized using in situ synchrotron X-ray diffraction. SFCA and SFCA-I are the key bonding phases in iron ore sinter, and an improved understanding of their formation mechanisms may lead to improved efficiency of industrial sintering processes. During heating, SFCA-I formation at 1327 K to 1392 K (1054 C to 1119 C) (depending on composition) was associated with the reaction of Fe2O3, 2CaOFe2O3, and SiO2. SFCA formation (1380 K to 1437 K [1107 C to 1164 C]) was associated with the reaction of CaOFe2O3, SiO2, and a phase with average composition 49.60, 9.09, 0.14, 7.93, and 32.15 wt pct Fe, Ca, Si, Al, and O, respectively. Increasing Al2O3 concentration in the starting sinter mixture increased the temperature range over which SFCA-I was stable before the formation of SFCA, and it stabilized SFCA to a higher temperature before it melted to form a Fe3O4 + melt phase assemblage (1486 K to 1581 K [1213 C to 1308 C]). During cooling, the first phase to crystallize from the melt (1452 K to 1561 K [1179 C to 1288 C]) was an Fe-rich phase, similar in composition to SFCA-I, and it had an average composition 58.88, 6.89, 0.82, 3.00, and 31.68 wt pct Fe, Ca, Si, Al, and O, respectively. At lower temperatures (1418 K to 1543 K [1145 C to 1270 C]), this phase reacted with melt to form SFCA. Increasing Al2O3 increased the temperature at which crystallization of the Fe-rich phase occurred, increased the temperature at which crystallization of SFCA occurred, and suppressed the formation of Fe2O3 (1358 K to 1418 K [1085 C to 1145 C]) to lower temperatures.

Webster, Nathan A. S.; Pownceby, Mark I.; Madsen, Ian C.; Kimpton, Justin A.

2012-12-01

17

Self-Tuning Multi-Step Prediction of Strength Index in an Iron-Ore Sintering Process.  

National Technical Information Service (NTIS)

A method which predicts sinter strength index (ISO) with reasonable accuracy several hours in advance is presented. The sintering process is characterized by a discrete time stochastic model, using ISO records and coke percentage in the raw mix. Practical...

P. P. Kanjilal E. Rose

1982-01-01

18

Assessment of exposure to PCDD/F, PCB, and PAH at a basic oxygen Steelmaking (BOS) and an iron ore sintering plant in the UK.  

PubMed

An assessment was carried out at a UK integrated steelworks to investigate the exposure of workers via inhalation to dioxins [polychlorinated dibenzo-p-dioxins (PCDD/F)], polychlorinated biphenyls (PCBs), and polycyclic aromatic hydrocarbons (PAH) including benzo[a]pyrene (B[a]P). Investigations focused on a basic oxygen steelmaking (BOS) plant and an iron ore sintering plant. The highest concentrations of PCDD/F and dioxin-like PCB were found at the BOS vessels and sinter strand area at the BOS and sinter plant, respectively. A risk assessment was carried out by comparing the daily intake of PCDD/F and PCB via inhalation with the recommended tolerable daily intake (TDI) proposed by the World Health Organisation (WHO). For the most exposed category of worker in this study (i.e. sinter plant workers inside the strand area), the estimated daily intake via inhalation was estimated to be 0.25 pg WHO-toxic equivalent concentrations (TEQ) kg(-1) body weight (bw). Considering that the average UK adult exposure to PCDD/F from the diet is 1.8 pg WHO-TEQ kg(-1) bw day(-1), the results indicated that the estimated daily intake of PCDD/F and PCB via inhalation for sinter plant workers would not result in the recommended range of the TDI (1-4 pg WHO-TEQ kg(-1) bw day(-1)) being exceeded. Cancer risks for a 40-year occupational exposure period were determined by multiplying the estimated intake by the inhalation cancer potency factor for 2,3,7,8-tetrachlorodibenzo-p-dioxin. For the most exposed category of worker, cancer risks from exposure to PCDD/F and PCB ranged from 2.5 10(-6) to 5.2 10(-5). Under most regulatory programmes, excess cancer risks between 1.0 10(-6) and 1.0 10(-4) indicate an acceptable range of cancer risk, suggesting a limited risk from PCDD/F and PCB exposure for workers in the sinter plant. With regard to PAH, B[a]P concentrations were typically <10 ng m(-3) at all locations at both the sinter plant and the BOS plant. In several cases, particularly at the sinter plant, B[a]P concentrations were well below or only marginally above the target value of 1 ng m(-3) specified in ambient air by the European Commission in the fourth 'Daughter' Directive of the Air Quality Framework Directive suggesting a very low risk of exposure for workers. For PAH, excess cancer risks ranged from 2.4 10(-6) to 7.3 10(-6) for BOS plant workers and from for 5.3 10(-7) to 1.5 10(-5) for sinter plant workers, well within the acceptable range proposed by the US EPA. PMID:21989166

Jackson, Kevin; Aries, Eric; Fisher, Raymond; Anderson, David R; Parris, Adrian

2011-10-11

19

Minerals Yearbook, 1989: Iron Ore.  

National Technical Information Service (NTIS)

The United States produced 59.03 million metric tons (Mmt) of usable iron ore during 1989. Although the tonnage was only slightly more than that of 1988, significant improvements were made in pellet quality. For the first time, fluxed pellets accounted fo...

P. H. Kuck C. M. Cvetic

1989-01-01

20

Biologically induced iron ore at Gunma iron mine, Japan  

Microsoft Academic Search

The mineralogy of sedimentary iron ores from the Gunma iron mine are described to evaluate the role of microorganisms and plants in ore formation. The iron ore is composed of nanocrystalline goethite, well-crystallized jarosite and very small amounts of strengite. The ore characteristically occurs as thick-bands of alternating goethite and jarosite bands, thin-bands of different goethite grain sizes, and fossil-aggregate

JUNJI AKAI; KURUMI AKAI; MAKOTO ITO; SATOSHI NAKANO; YONOSUKE MAKI; ICHIRO SASAGAWA

1999-01-01

21

Microbial community study of the iron ore concentrate of the Sishen Iron Ore Mine, South Africa  

Microsoft Academic Search

As a result of the advancing global technologies and civilisation, there has been a progressive depletion of high-grade mineral\\u000a deposits. Consequently, it has become increasingly important to process lower-grade ores. Phosphorous (P) and particular potassium\\u000a (K) contained in the iron ore concentrates of the Sishen Iron Ore Mine have a detrimental effect on the steel making process,\\u000a whereby these alkalis

P. J. Williams; T. E. Cloete

2008-01-01

22

A pilot study for determining the optimal operation condition for simultaneously controlling the emissions of PCDD/Fs and PAHs from the iron ore sintering process.  

PubMed

In this study, the cost-benefit analysis technique was developed and incorporated into the Taguchi experimental design to determine the optimal operation combination for the purpose of providing a technique solution for controlling both emissions of PCDD/Fs and PAHs, and increasing both the sinter productivity (SP) and sinter strength (SS) simultaneously. Four operating parameters, including the water content, suction pressure, bed height, and type of hearth layer, were selected and all experimental campaigns were conducted on a pilot-scale sinter pot to simulate various sintering operating conditions of a real-scale sinter plant. The resultant optimal combination could reduce the total carcinogenic emissions arising from both emissions of PCDD/Fs and PAHs by 49.8%, and increase the sinter benefit associated with the increase in both SP and SS by 10.1%, as in comparison with the operation condition currently used in the real plant. The ANOVA results indicate that the suction pressure was the most dominant parameter in determining the optimal operation combination. The above result was theoretically plausible since the higher suction pressure provided more oxygen contents leading to the decrease in both PCDD/F and PAH emissions. But it should be noted that the results obtained from the present study were based on pilot scale experiments, conducting confirmation tests in a real scale plant are still necessary in the future. PMID:22704976

Chen, Yu-Cheng; Tsai, Perng-Jy; Mou, Jin-Luh; Kuo, Yu-Chieh; Wang, Shih-Min; Young, Li-Hao; Wang, Ya-Fen

2012-06-16

23

Micromorphology, chemistry, and mineralogy of bog iron ores from Poland  

Microsoft Academic Search

The influence of different land use history on the chemistry, mineralogy, and micromorphology of bog iron ores was studied in the vicinity of Warsaw, Poland. At three Holocene terraces of the Vistula River, eight profiles were chosen, which represent three different types of bog iron ore: (i) continuous hard layers (meadow, fallow at Wilanow), (ii) horizons with small ore fragments

Danuta Kaczorek; Michael Sommer

2003-01-01

24

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE ...  

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

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE CARS TOWARDS WESTERN SIDE OF CLEVELAND BULK TERMINAL BUILDINGS AND A SELF-UNLOADING IRON ORE SHIP AT DOCK. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

25

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE ...  

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

CONTEXT VIEW ALONG EXISTING PERIMETER TRACKS LOOKING OVER IRON ORE CARS TOWARDS CLEVELAND BULK TERMINAL BUILDINGS. LOOKING SOUTH. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

26

Iron ore weathering potentials of ectomycorrhizal plants.  

PubMed

Plants in association with soil microorganisms play an important role in mineral weathering. Studies have shown that plants in symbiosis with ectomycorrhizal (ECM) fungi have the potential to increase the uptake of mineral-derived nutrients. However, it is usually difficult to study many of the different factors that influence ectomycorrhizal weathering in a single experiment. In the present study, we carried out a pot experiment where Pinus patula seedlings were grown with or without ECM fungi in the presence of iron ore minerals. The ECM fungi used included Pisolithus tinctorius, Paxillus involutus, Laccaria bicolor and Suillus tomentosus. After 24 weeks, harvesting of the plants was carried out. The concentration of organic acids released into the soil, as well as potassium and phosphorus released from the iron ore were measured. The results suggest that different roles of ectomycorrhizal fungi in mineral weathering such as nutrient absorption and transfer, improving the health of plants and ensuring nutrient circulation in the ecosystem, are species specific, and both mycorrhizal roots and non-mycorrhizal roots can participate in the weathering process of iron ore minerals. PMID:22349958

Adeleke, R A; Cloete, T E; Bertrand, A; Khasa, D P

2012-02-21

27

40 CFR 440.10 - Applicability; description of the iron ore subcategory.  

Code of Federal Regulations, 2010 CFR

...true Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

2009-01-01

28

40 CFR 440.10 - Applicability; description of the iron ore subcategory.  

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the iron ore subcategory. 440.10 Section...MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability; description of the iron ore subcategory. The provisions...

2013-07-01

29

Thermal investigations of direct iron ore reduction with coal  

Microsoft Academic Search

In this paper, fundamental mechanisms for iron ore reduction in coalore mixtures have been investigated using several advanced experimental techniques. Firstly, the thermal properties of coalore mixtures were studied and apparent specific heat of coalore mixtures against temperature was obtained at a heating rate of 10C\\/min. Several exothermic and endothermic peaks were observed which were related to the decomposition reactions

Gui-su Liu; Vladimir Strezov; John A Lucas; Louis J Wibberley

2004-01-01

30

Computer aids for production systems management in iron ore mining  

Microsoft Academic Search

Iron ore is railed to port, crushed to lump and fines, stockpiled and shipped. Product quality requires consistent composition, in iron and other minerals. Decision support systems described here aid daily ore selection, to maintain target composition. The method evolved from a batch system, building each stockpile to target, to a flow process, targeting an exponentially smoothed continuous stockpile. This

J. E. Everett

2007-01-01

31

Iron Ore Mines Leachate Potential for Oxyradical Production  

Microsoft Academic Search

The ecotoxicological effects of mining effluents is coming under much greater scrutiny. It appears necessary to explore possible health effects in association with iron ore mining effluents. The present results clearly demonstrate that iron-ore leachate is not an inert media but has the potential to induce lipid peroxidation. Peroxidation was assessed by measuring oxygen consumption in the presence of a

D. Hamoutene; A. Rahimtula; J. Payne

2000-01-01

32

Definitional Mission Report: An Iron Ore Mining Project in Senegal.  

National Technical Information Service (NTIS)

At the request of the Senegalese Government and the national iron ore company, MIFERSO, the U.S. Trade and Development Program (TDP) sent a Definitional Mission to Senegal to evaluate an iron ore project in Senegal. Based upon the findings of the mission,...

B. P. Canning V. K. Shrivastava

1991-01-01

33

FACTORS AFFECTING THE REDUCIBILITY OF SINTERED CHROMITE PELLETS AND CHROMITE LUMPY ORE  

Microsoft Academic Search

The energy consumption and recovery of chromium are important economic factors in ferrochrome produc- tion. Outokumpu has a lot of experience of the reduction behavior of the sintered pellets in industrial-scale furnaces and also on the grounds of numerous laboratory and pilot-scale investigations. Sintered pellets have shown a superiority over lumpy ore and briquettes made of the same chromite grade.

T. Lintumaa; H. Krogerus; P. Jokinen

34

Identification of Sintered Irons with Ultrasonic Nonlinearity  

NASA Astrophysics Data System (ADS)

Two kinds of sinters made of reduced and atomized iron powders were identified by nonlinear ultrasonic measurement to detect higher harmonics generated at micro gaps comparable to the incident wave amplitude using PZT contact transducers of 5 MHz and 10 MHz. Furthermore, the advantage of the nonlinear ultrasonic measurement was demonstrated by the attenuation coefficient measurement for same samples.

Ohara, Y.; Kawashima, K.; Murase, M.; Hirose, N.

2003-03-01

35

40 CFR 440.10 - Applicability; description of the iron ore subcategory.  

Code of Federal Regulations, 2010 CFR

...false Applicability; description of the iron ore subcategory. 440.10 Section 440.10...CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Iron Ore Subcategory § 440.10 Applicability;...

2010-07-01

36

26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.  

Code of Federal Regulations, 2013 CFR

... Expenditures relating to disposal of coal or domestic iron ore. 1.272-1 ...Expenditures relating to disposal of coal or domestic iron ore. (a) Introduction...hereafter sometimes referred to as a coal royalty contract or iron ore...

2013-04-01

37

Challenges Facing the North American Iron Ore Industry.  

National Technical Information Service (NTIS)

This report is derived from a presentation the author presented in late September at the Iron Ore 2005 Conference sponsored by The Australasian Institute of Mining and Metallurgy and held in Fremantle, Western Australia. Some slight revisions have been ma...

J. D. Jorgenson

2006-01-01

38

Microbial Beneficiation of Salem Iron Ore Using Penicillium purpurogenum  

NASA Astrophysics Data System (ADS)

High alumina and silica content in the iron ore affects coke rate, reducibility, and productivity in a blast furnace. Iron ore is being beneficiated all around the world to meet the quality requirement of iron and steel industries. Choosing a beneficiation treatment depends on the nature of the gangue present and its association with the ore structure. The advanced physicochemical methods used for the beneficiation of iron ore are generally unfriendly to the environment. Biobeneficiation is considered to be ecofriendly, promising, and revolutionary solutions to these problems. A characterization study of Salem iron ore indicates that the major iron-bearing minerals are hematite, magnetite, and goethite. Samples on average contains (pct) Fe2O3-84.40, Fe (total)-59.02, Al2O3-7.18, and SiO2-7.53. Penicillium purpurogenum (MTCC 7356) was used for the experiment . It removed 35.22 pct alumina and 39.41 pct silica in 30 days in a shake flask at 10 pct pulp density, 308 K (35 C), and 150 rpm. In a bioreactor experiment at 2 kg scale using the same organism, it removed 23.33 pct alumina and 30.54 pct silica in 30 days at 300 rpm agitation and 2 to 3 l/min aeration. Alumina and silica dissolution follow the shrinking core model for both shake flask and bioreactor experiments.

Mishra, M.; Pradhan, M.; Sukla, L. B.; Mishra, B. K.

2011-02-01

39

Capital and Labor Requirements for Iron Ore Mining and Beneficiating.  

National Technical Information Service (NTIS)

The inputs of capital and labor needed for future expansion of iron ore supply to the United States were developed from projections of demand for iron and estimates of capital and labor requirements per ton of capacity. Trends in technologic change and th...

R. J. Leary D. J. Kusler

1975-01-01

40

Ocean environment and developing of oceanic iron-manganese ores  

NASA Astrophysics Data System (ADS)

This work is devoted to some problems of the genesis, chemical composition, and forming rates of iron-manganese ores (IMOs) in the ocean bed due to real outlooks of their development in the years 2015-2020. It is particularly accentuated that ores are continuously originating on the ocean bed with rates of several millimeters per million years. IMO accumulation in modern oceans is greatly more than the age of the mobile ocean bed. These unique ores are not only sorbents of some strategic microelements, but also store easily mobilized oxygen, which is able to supersaturate water in endogenic processes on the ocean bed, blocking their expansion in a limited volume. Thus, iron-manganese ores must be mined only with nonpolluting methods and under the control of competent authorities.

Bazilevskaya, E. S.

2009-12-01

41

Rare earth-iron-boron sintered magnets  

SciTech Connect

This paper describes a method for a permanent magnet comprising a heavy lanthanide metal near the grain boundaries of light rare earth-iron-boron particles. It comprises: mixing a particulate alloy containing at least one light rare earth metal, iron, boron, a ferromagnetic metal selected from the group consisting of nickel, cobalt, and mixtures thereof with at least one particulate metal additive containing a heavy lanthanide metal, the particulate alloy comprising a main magnetic phase having an empirical formula of about Nd{sub 2}(FeCo){sub 14}B; aligning magnetic domains of the mixture in a magnetic field; compacting the aligned mixture to form a shape; and sintering the compacted shape for sufficient time to produce the permanent magnet having the heavy lanthanide metal near the grain boundaries of particles of the main magnetic phase.

Ghandehari, M.H.

1991-05-14

42

The design and application of the ore pulp water treatment in pipeline transport of refined iron ore  

Microsoft Academic Search

The water treatment in conduits, which delivers the ore pulp for a long distance, is a problem that can affect the industries of solid material conduit delivering, due to the special physical characteristics of the ore pulp slurry. The running conduits of Yunnan DaHongshan ore of iron refined is the one of the most running difficult conduits in the world,

Pu Guangyue; Wu Jiande; An Jian; Wang Jian; Ba Haibo; Wang Xiaodong

2010-01-01

43

26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.  

Code of Federal Regulations, 2010 CFR

...coal royalty contract (or iron ore royalty contract) to which such...disposal by the owner of coal or iron ore held by him for more than 1 year...631(c) even though the actual mining of coal or iron ore under the coal royalty...

2009-04-01

44

Pelletized vs. natural iron ore technology: energy, labor, and capital changes. Final report  

Microsoft Academic Search

Total energy requirements per ton of iron-in-ore for natural and pelletized ore were calculated by a hybrid energy analysis. Energy requirements for ore preparation were subsequently considered as one energy input (embodied) to blast furnaces. Total energy requirements per ton molten iron were calculated for each year from 1955 through 1975 to identify changes attributable to the shift in iron

Kakela

1978-01-01

45

Iron isotope fractionation during hydrothermal ore deposition and alteration  

NASA Astrophysics Data System (ADS)

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 ?56Fe between -2.3 and +1.3. Primary hematite (?56Fe: -0.5 to +0.5) precipitated by mixing oxidizing surface waters with a hydrothermal fluid that contained moderately light Fe (?56Fe: -0.5) leached from the crystalline basement. Occasional input of CO2-rich waters resulted in precipitation of isotopically light siderite (?56Fe: -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.

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

2006-06-01

46

Environmental impact of iron ore mines in Goa, India  

Microsoft Academic Search

Environmental impact assessment studies were carried out in the iron ore mining areas of the Goa region using both qualitative and quantitative methods. From the qualitative approach it was observed that surface excavations and solid waste disposal are more responsible for affecting the environmental parameters like soils, land forms, ground water, surface water and flora. From the R?mode factor analysis

D. S. Ratha; G. Venkataraman

1995-01-01

47

Role of bacterial interaction and bioreagents in iron ore flotation  

Microsoft Academic Search

Interaction between Paenibacillus polymyxa and iron ore minerals such as hematite, corundum, calcite, quartz and kaolinite brought about significant surface chemical changes on all the minerals. Quartz and kaolinite were rendered more hydrophobic, while the other three minerals became more hydrophilic after bacterial interaction. Predominance of bacterial polysaccharides on interacted hematite, corundum and calcite and of proteins on quartz and

K. A Natarajan; Namita Deo

2001-01-01

48

Sintered iron filters for the fine purification of diesel fuel  

Microsoft Academic Search

1.Iron powder obtained by grinding compacted reduced scale in ball mills is suitable for the manufacture of high-flow sintered filters and, in particular, filters for the fine purification of Diesel fuel.2.By additional rolling of powders in mullers, it is possible to increase the throughput of sintered filters by 3555%.

V. N. Morozov; Yu. N. Semenov

1965-01-01

49

26 CFR 1.272-1 - Expenditures relating to disposal of coal or domestic iron ore.  

Code of Federal Regulations, 2010 CFR

...relating to disposal of coal or domestic iron ore. 1.272-1 Section 1.272-1...relating to disposal of coal or domestic iron ore. (a) Introduction. Section...as a coal royalty contract or iron ore royalty contract) for the...

2010-04-01

50

Direct reduction of iron ore by biomass char  

NASA Astrophysics Data System (ADS)

By using thermogravimetric analysis the process and mechanism of iron ore reduced by biomass char were investigated and compared with those reduced by coal and coke. It is found that biomass char has a higher reactivity. The increase of carbon-to-oxygen mole ratio (C/O) can lead to the enhancement of reaction rate and reduction fraction, but cannot change the temperature and trend of each reaction. The reaction temperature of hematite reduced by biomass char is at least 100 K lower than that reduced by coal and coke, the maximum reaction rate is 1.57 times as high as that of coal, and the final reaction fraction is much higher. Model calculation indicates that the use of burden composed of biomass char and iron ore for blast furnaces can probably decrease the temperature of the thermal reserve zone and reduce the CO equilibrium concentration.

Zuo, Hai-bin; Hu, Zheng-wen; Zhang, Jian-liang; Li, Jing; Liu, Zheng-jian

2013-06-01

51

Strain-enhanced sintering of iron powders  

NASA Astrophysics Data System (ADS)

Sintering of ball-milled and un-milled Fe powders has been investigated using dilatometry, X-ray, density, and positron annihilation techniques. A considerable sintering enhancement is found in milled powders showing apparent activation energies that range between 0.44 and 0.80 eV/at. The positron annihilation results, combined with the evolution of the shrinkage rate with sintering temperature, indicate generation of lattice defects during the sintering process of milled and un-milled powders. The sintering enhancement is attributed to pipe diffusion along the core of moving dislocations in the presence of the vacancy excess produced by plastic deformation. Positron annihilation results do not reveal the presence of sintering-induced defects in un-milled powders sintered above 1200 K, the apparent activation energy being in good agreement with that for grain-boundary diffusion in ?-Fe.

Amador, D. R.; Monge, M. A.; Torralba, J. M.; Pareja, R.

2005-02-01

52

Raman Spectroscopic Characterisation of Australian Banded Iron Formation and Iron Ore  

NASA Astrophysics Data System (ADS)

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.

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

2012-04-01

53

Simulation of primary-slag melting behavior in the cohesive zone of a blast furnace, considering the effect of Al{sub 2}O{sub 3}, Fe{sub t}O, and basicity in the sinter ore  

SciTech Connect

The alumina content in the iron ore imported to Japan is increasing year by year, and some problems in blast furnace operation, due to the use of the high-alumina-containing sinter, have already been reported. In order to clarify the mechanism of the harmful effect of alumina on the blast furnace operation, the behavior of the primary melt, which is formed in the sinter at the cohesive zone of the blast furnace, has been simulated by dripping slag through an iron or oxide funnel. The effects of basicity, Al{sub 2}O{sub 3}, and Fe{sub t}O contents in the five slag systems on the dripping temperature and weight of slag remaining on the funnel have been discussed. It was found that the eutectic melt formed in the sinter would play an important role in the dripping behavior of the slag in the blast furnace through the fine porosity of the reduced iron and ore particles. Al{sub 2}O{sub 3} increased the weight of the slag remaining on the funnel, and its effect became very significant in the acidic and low-Fe{sub t}O-containing slag. It was estimated that the increase of the weight of the slag remaining on the funnel by Al{sub 2}O{sub 3} in the ore could result in a harmful effect on the permeability resistance and an indirect reduction rate of the sinter in the blast furnace.

Hino, Mitsutaka; Nagasaka, Tetsuya; Katsumata, Akitoshi [Tohoku Univ., Sendai (Japan). Dept. of Metallurgy; Higuchi, Kenichi; Yamaguchi, Kazuyoshi; Kon-No, Norimitsu [Nippon Steel Corp., Futts (Japan). Process Technology Research Labs.

1999-08-01

54

High-carbon fly-ash as a binder for iron ore pellets  

SciTech Connect

The goal of this project was to convert currently unusable fly-ashes into a material that can be used as a binder for iron ore. Such a binder would also be useful for other high-volume markets, including foundry sand mold binders. Previously, the investigators used fly-ash in combination with calcium hydroxide as an additive while calcium chloride was added as a hardening accelerator. However, the addition of chloride salts have a detrimental effect because chlorine causes corrosion in processing equipment. Therefore, other potential hardening accelerators were investigated during this project. During production, dried iron-ore pellets are required to have crushing strength of at least 22.2 newtons (5 pounds force) per 12.7 mm (1/2 inch) diameter pellet. The pellets are then sintered at temperatures up to 1300 C and must not exhibit a significant degree of spalling or cracking. Pellets will therefore be tested to determine whether acceptable dry crushing strengths can be achieved.

Kawatra, S.K.; Eisele, T.C.; Ripke, S.J.; Ramirez, G.

1999-09-01

55

Siderite formation and evolution of sedimentary iron ore deposition in the Earths history  

Microsoft Academic Search

The role of siderite in Phanerozoic and Precambrian iron formations is discussed. Various types of iron formations are characterized,\\u000a and their place in the evolution of sedimentary iron ore deposition is outlined. In Precambrian iron ore deposition, siderite\\u000a is a primary mineral, whereas in Phanerozoic iron formations it becomes a secondary mineral and is commonly related to diagenetic\\u000a and catagenetic

V. N. Kholodov; G. Yu. Butuzova

2008-01-01

56

Synthesis of Fe-MCM-41 Using Iron Ore Tailings as the Silicon and Iron Source.  

PubMed

Highly ordered Fe-MCM-41 molecular sieve was successfully synthesized by using n-hexadecyl-trimethyl ammonium bromide (CTAB) as the template and the iron ore tailings (IOTs) as the silicon and iron source. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance UV-visible spectroscopy, (29)Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR), and nitrogen adsorption/desorption were used to characterize the samples. The results showed that the mesoporous materials had highly ordered 2-dimensional hexagonal structure. The synthesized sample had high surface area, and part of iron atoms is retained in the framework with formation of tetrahedron after removal of the template by calcinations. The results obtained in the present work demonstrate the feasibility of employing iron ore tailings as a potential source of silicon and iron to produce Fe-MCM-41 mesoporous materials. PMID:22567574

Li, Xin; Yu, Honghao; He, Yan; Xue, Xiangxin

2012-04-03

57

Synthesis of Fe-MCM-41 Using Iron Ore Tailings as the Silicon and Iron Source  

PubMed Central

Highly ordered Fe-MCM-41 molecular sieve was successfully synthesized by using n-hexadecyl-trimethyl ammonium bromide (CTAB) as the template and the iron ore tailings (IOTs) as the silicon and iron source. X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), diffuse reflectance UV-visible spectroscopy, 29Si magic-angle spinning (MAS) nuclear magnetic resonance (NMR), and nitrogen adsorption/desorption were used to characterize the samples. The results showed that the mesoporous materials had highly ordered 2-dimensional hexagonal structure. The synthesized sample had high surface area, and part of iron atoms is retained in the framework with formation of tetrahedron after removal of the template by calcinations. The results obtained in the present work demonstrate the feasibility of employing iron ore tailings as a potential source of silicon and iron to produce Fe-MCM-41 mesoporous materials.

Li, Xin; Yu, Honghao; He, Yan; Xue, Xiangxin

2012-01-01

58

From banded iron-formation to iron ore: geochemical and mineralogical constraints from across the Hamersley Province, Western Australia  

Microsoft Academic Search

Several major iron ore deposits occur in deformed regions of the Hamersley Province, Western Australia, where banded iron-formation (BIF) of the Dales Gorge Member has been converted to martite and microplaty hematite. The genesis of these high-grade hematite ores remains controversial, in part because no study has systematically documented variations on the chemistry and mineralogy of stratigraphically equivalent rocks from

Adam D. Webb; Gerald R. Dickens; Nicholas H. S. Oliver

2003-01-01

59

Phytostabilization of iron ore tailings through Calophyllum inophyllum L.  

PubMed

The phytostabilization of waste material generated during mining and processing of iron ore through Calophyllum inophyllum L. have been investigated. Iron ore tailings and its varying composition with garden soil were taken to study plant growth, chlorophyll content and metal uptake pattern of Calophyllum inophyllum L. These studies indicate that 100% survival of plant species was noted in all the treatments without any toxicity symptoms. The increase in growth parameters and chlorophyll content along with the high metal accumulation in plant tissues suggests that Calophyllum inophyllum L. may be a potential tool for phytoremediation. The accumulation of Pb (1662 microgm/gm) and Fe (2313 microgm/gm) was observed to be maximum in the plant tissues followed by Cu, Zn, Cr, and Ni. The TF values for most of the heavy metals was observed to be > 1 which indicates that the plant can efficiently translocate these toxic metals to its above ground parts. Removal of more than 30% of the most of the heavy metal like Fe, Pb, and Cu & Zn has been observed in all the treatments during one year of observation. The overall study clearly suggests that the plant can be used as an efficient tool for restoration of mining wastes and other similarly contaminated sites. PMID:22908660

Chaturvedi, Nilima; Dhal, N K; Reddy, Palli Sita Rama

2012-12-01

60

The Analysis on the Sensitivity of Steel Enterprise to Iron Ore Price  

Microsoft Academic Search

In order to analyze the different influences on Chinese domestic and abroad steel enterprises from a rise in material prices, this paper mainly researches on the sensitivity of major steel companies' cost to iron ore price and coke price. It applys sensitivity analysis to show the dependence of enterprise on iron ore and adapts panel data model to make a

Yingming Mao; Han Qiao

2011-01-01

61

Nondestructive Evaluation of Sintered Iron Using Dynamic Young's Modulus Testing  

Microsoft Academic Search

In this study, the model in which Young's modules(E) depends on only porosity (P) was investigated by the experimental results of sintered iron, and new equation of Young's modulus against porosity was derived. The equation was confirmed by applying to the relationship between Young's modulus and porosity obtained by the acoustic pulse method and the resonance frequency method. The derived

Norimitsu Hirose; Shin-Ichi Tanaka; Junichi Asami; Tohru Kohno

2001-01-01

62

Nondestructive evaluation of elastic parameters of sintered iron powder compacts  

Microsoft Academic Search

A systematic study of the variation of elastic moduli and Poisson's ratio of sintered iron compacts of porosity (up to 21.6%) has been carried out by measuring longitudinal and shear ultrasonic velocities. The variation of these parameters with porosity is compared with predictions of elasticity and scattering theories. Further, a linear relationship was observed between the elastic moduli and the

J. P. Panakkal; H. Willems; W. Arnold

1990-01-01

63

20 CFR 404.1084 - Gain or loss from disposition of property; capital assets; timber, coal, and iron ore...  

Code of Federal Regulations, 2010 CFR

...from disposition of property; capital assets; timber, coal, and iron ore; involuntary...from disposition of property; capital assets; timber, coal, and iron ore; involuntary...From the disposal of iron ore mined in the...other disposition of property that is not...

2009-04-01

64

20 CFR 404.1084 - Gain or loss from disposition of property; capital assets; timber, coal, and iron ore...  

Code of Federal Regulations, 2010 CFR

...from disposition of property; capital assets; timber, coal, and iron ore; involuntary...from disposition of property; capital assets; timber, coal, and iron ore; involuntary...From the disposal of iron ore mined in the...other disposition of property that is not...

2010-04-01

65

Production of an iron ore concentrate from the iron-rich fraction of power plant fly ash  

Microsoft Academic Search

Removal of gangue materials, principally silica and alumina, from a magnetically-separated, iron-rich fraction of bituminous coal fly ash shows promise of yielding an iron ore grade concentrate. As separated, the iron-rich fraction contains 65 to 75 weight percent iron oxides or about 50% of the iron originally in the ash. Removal of the iron-rich fraction is a first step in

M. S. Dobbins; G. Burnet

1981-01-01

66

Cooling process of iron ore pellets in an annular cooler  

NASA Astrophysics Data System (ADS)

A 3-D mathematical model was presented for the cooling process of iron ore pellets based on the laws of mass, momentum, and heat transfer. The flow, pressure, and temperature fields were obtained by numerical simulation with the commercial software FLUENT. In order to verify the model, a mass and energy balance field test was systematically carried out on an annular cooler in Shougang Mining Company. The maximum relative errors of temperature, pressure, and velocity between computational and testing results are 2.87%, -8.11%, and 7.14%, respectively, indicating the validity of the model. Further, the effects of process parameters, such as pellet diameter, bed thickness, air velocity, and temperature, on the pellet bed temperature profiles were studied.

Feng, Jun-Xiao; Liang, Kai-Li; Sun, Zhi-Bin; Xu, Jing-Hai; Zhang, Yong-Ming; Yang, Jin-Bao

2011-06-01

67

Bioextraction (reductive dissolution) of iron from low-grade iron ores. Fundamental and applied studies.  

PubMed

Results of the present study indicate that S. putrefaciens 200 may be a suitable Fe(3+)-reducing microorganism for commercial application in a microbially catalyzed iron ore bioextraction (reductive dissolution) process. The proposed scheme of the bioextraction process (Fig. 1) entails the addition of a suitable iron ore to anaerobic, batch cultures of aerobically grown S. putrefaciens 200, with subsequent recovery of Fe2+ in the product stream. Although batch growth under low oxygen tension is known to induce expression of the high-rate Fe3+ reduction system in S. putrefaciens, such growth conditions do not appreciably enhance the rate at which S. putrefaciens catalyzes the reductive dissolution of iron from low-grade iron ore. As a result, strict monitoring of dissolved oxygen levels during batch growth is not required. Highly aerobic growth conditions are most desirable because such conditions maximize microbial growth rates. Commercial application of the proposed process is made more attractive by the ability to grow S. putrefaciens aerobically on a relatively inexpensive organic substrate (filter-sterilized, primary effluent wastewater) as sole carbon and energy source. Physical and chemical factors that accelerate overall reductive dissolution rates include (i) pulverization of the iron ores before their addition to the anaerobic, batch cultures, and (ii) subsequent addition of an Fe(III)-chelating agent to the anaerobic iron ore-microorganism slurry. Recycle of residual ore remaining in the initial reactor vessel after a one-hour incubation is recommended, since overall reductive dissolution rates decrease dramatically after that time. Significant enhancement of the overall reductive dissolution rates may reside in the ability to genetically engineer a more robust Fe(3+)-reducing microorganism. Preliminary genetic studies presented here indicate that S. putrefaciens is a suitable model microorganism for studying the molecular basis of microbial Fe3+ reduction. Mutagenesis experiments demonstrated that the Fe3+ reduction system of S. putrefaciens is physiologically uncoupled from other electron-accepting processes carried out by this bacterium, and that a distinct ferrireductase enzyme is expressed after growth under either highly aerobic or microaerobic conditions. An array of S. putrefaciens mutants (Class I), deficient only in their ability to grow anaerobically on Fe3+ as sole terminal electron acceptor, were isolated and a single mutant selected for subsequent gene cloning (complementation) experiments. Restriction enzyme analysis of putative, complemented clones (i.e., transconjugates in which the ability to grow anaerobically on Fe3+ had been restored) revealed the presence of a common cloned DNA insert.(ABSTRACT TRUNCATED AT 400 WORDS) PMID:8010693

DiChristina, T J

1994-05-01

68

Low temperature sintering of iron deficient Z type hexagonal ferrites  

Microsoft Academic Search

Low temperature sintering of iron deficient hexagonal Co2Z type ferrites is attempted to prepare a chip inductor for ultra high frequency uses. It should be attained below the melting point of silver (960C) used as the electrode material of the chip inductor. The best result is obtained for the sample with the composition 2.15Co0.6Cu0.4O3Ba0.79Sr0.16Bi0.05O9.725Fe2O3 sintered at 925C containing 0.5wt.% of

Osamu Kimura; Kazuo Shoji; Hiroshi Maiwa

2006-01-01

69

Effects of calcium hydroxide and calcium chloride addition to bentonite in iron ore pelletization.  

PubMed

Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder. PMID:17121116

Tugrul, Nurcan; Derun, Emek Moroydor; Pi?kin, Mehmet

2006-10-01

70

Liquid-phase sintering of iron aluminide-bonded ceramics  

SciTech Connect

Iron aluminide intermetallics exhibit excellent oxidation and sulfidation resistance and are therefore considered as the matrix in metal matrix composites, or the binder in hard metals or cermets. In this paper the authors discuss the processing and properties of liquid-phase sintered iron aluminide-bonded ceramics. It is found that ceramics such as TiB{sub 2}, ZrB{sub 2}, TiC, and WC may all be liquid phase-sintered. nearly complete densification is achieved for ceramic volume fractions ranging up to 60%. Depending on the composition, room temperature three point-bend strengths and fracture toughnesses reaching 1,500 MPa and 30 MPa m{sup 1/2}, respectively, have been found. Since the processing was carried out in a very simple manner, optimized processing is likely to result in further improvements.

Schneibel, J.H.; Carmichael, C.A. [Oak Ridge National Lab., TN (United States). Metals and Ceramics Div.

1995-12-31

71

Separation of Trace Elements from Iron, and the Analysis of Iron-Rich Ores for Use as Reference Materials.  

National Technical Information Service (NTIS)

Iron(III) chloride is separated from the trace elements in iron ores. After dissolution of the sample, the iron in 6M hydrochloric acid solution is separated, by liquid-liquid extraction with methyl isobutyl ketone, from the alkali metals, alkaline earth ...

E. A. Jones

1982-01-01

72

The Separation of Trace Elements from Iron, and the Analysis of Iron-Rich Ores for Use as Reference Materials.  

National Technical Information Service (NTIS)

Iron(III) chloride is separated from the trace elements in iron ores. After dissolution of the sample, the iron in 6M hydrochloric acid solution is separated, by liquid-liquid extraction with methyl isobutyl ketone, from the alkali metals, alkaline earth ...

E. A. Jones

1982-01-01

73

Production of an Iron Ore Concentrate from the Iron-Rich Fraction of Power Plant Fly Ash.  

National Technical Information Service (NTIS)

Removal of gangue materials, principally silica and alumina, from a magnetically-separated, iron-rich fraction of bituminous coal fly ash shows promise of yielding an iron ore grade concentrate. As separated, the iron-rich fraction contains 65 to 75 weigh...

M. S. Dobbins G. Burnet

1981-01-01

74

Fatigue strength of sintered iron-base antifriction materials  

Microsoft Academic Search

1.Sintered antifriction materials based on iron powder lose much of their strength when subjected to cyclic loading.2.Increasing the porosity of these materials substantially lowers both their static and fatigue strengths. It should be noted in this connection that the dependence of the static strength on porosity is similar in character to the dependence of the fatigue strength on porosity.3.Increasing the

I. D. Radomysel'skii; B. A. Gryaznov; V. G. Semashko

1968-01-01

75

Iron ore and coal: pricing and volume up for these key export commodities  

SciTech Connect

Australia's huge coal and iron ore industries are booming. Up until now, the majors have benefited handsomely, but smaller players are beginning to muscle in. The article discusses development in both industries. 1 fig., 4 photos.

NONE

2006-01-15

76

Studies on removal of lead ions from aqueous solutions using iron ore slimes as adsorbent  

Microsoft Academic Search

Iron ore slimes, a waste material generated during iron ore mining have been employed for the removal of lead ions from aqueous\\u000a solutions by a batch adsorption technique. The slime sample contains 45.8% Fe, 13.6% SiO2, and 13.9% Al2O3. It is characterized by X-ray diffraction (XRD) and optical microscopy to determine the presence of different phases such\\u000a as hematite, goethite,

Laxmipriya Panda; Bisweswar Das; Danda Srinivas Rao

77

High temperature compatibility of nitrate salts, granite rock and pelletized iron ore  

Microsoft Academic Search

Under the direction of the Department of Energy, high-temperature (550°C) thermal energy storage concepts are being studied for application with second-generation solar central receiver thermal power systems. The report evaluates the compatibility of the current choice of working fluids with common granite rock and a pelletized iron ore. Results indicate that the long-term stability of iron-ore pellets in binary mixtures

V. P. Burolla; J. J. Bartel

1979-01-01

78

An Approach to Overseas Iron Ore Investment Risk Assessment Based on Fuzzy Neural Network  

Microsoft Academic Search

\\u000a The iron ore investment overseas influenced by a variety of risk factors including geological reserves risk, market risk,\\u000a the risk of the investment environment, political and legal risks, and etc. Based on the theory of risk assessment, this paper\\u000a firstly analyzed the risk from the asset influence and frequency of threat, set up risk level structure of overseas iron ore

Li Guo; Caiwu Lu; Zhen Yang

79

Mineralogy, Microstructure, and Chemical Composition of Goethites in Some Iron Ore Deposits of Orissa, India  

Microsoft Academic Search

The JodaBarbil region of the JamdaKoira valley is one of the most important sources of iron ores in India. The mineralogy, texture, and chemical composition of iron ore of the region have been analyzed to understand the presence of different types of goethite and their compositional variation with respect to Fe, Al2O3, SiO2, and P that are essential for upgrading

S. K. Das; B. Das; R. Sakthivel; B. K. Mishra

2010-01-01

80

Content and binding forms of heavy metals, aluminium and phosphorus in bog iron ores from Poland.  

PubMed

Bog iron ores are widespread in Polish wetland soils used as meadows or pastures. They are suspected to contain high concentrations of heavy metals, which are precipitated together with Fe along a redox gradient. Therefore, soils with bog iron ore might be important sources for a heavy metal transfer from meadow plants into the food chain. However, this transfer depends on the different binding forms of heavy metals. The binding forms were quantified by sequential extraction analysis of heavy metals (Fe, Mn, Cr, Co, Ni, Cd, Pb) as well as Al and P on 13 representative samples of bog iron ores from central and southwestern Poland. Our results showed total contents of Cr, Co, Ni, Zn, Cd, and Pb not to exceed the natural values for sandy soils from Poland. Only the total Mn was slightly higher. The highest contents of all heavy metals have been obtained in iron oxide fractions V (occluded in noncrystalline and poorly crystalline Fe oxides) and VI (occluded in crystalline Fe oxides). The results show a distinct relationship between the content of Fe and the quantity of Zn and Pb as well P. Water soluble as well as plant available fractions were below the detection limit in most cases. From this we concluded bog iron ores not to be an actual, important source of heavy metals in the food chain. However, a remobilization of heavy metals might occur due to any reduction of iron oxides in bog iron ores, for example, by rising groundwater levels. PMID:19398508

Kaczorek, Danuta; Brmmer, Gerhard W; Sommer, Michael

2009-04-27

81

Influence of porosity on fatigue cumulative damage of sintered iron  

NASA Astrophysics Data System (ADS)

Fatigue represents a common mechanical condition during service for materials used in structural components. This type of loading becomes particularly critical when alternating stress amplitude may be expected to vary, or change, in some way during the service life. Such variations and changes in load amplitude make the direct use of standard S-N curves inapplicable, because these curves are developed and presented for constant stress amplitude operation. In the present paper, results of cumulative damage under fatigue of porous materials are reported. The specimens used were produced by compacting and sintering iron powder. Their as-sintered porosity contents were P 0 = 4.1 and 12.4 %. Uniaxial fatigue tests (tensile-compression) were carried out at room temperature on a hydraulic testing machine.

Palma, E. S.

1997-10-01

82

Characterization of magnetotactic bacteria and their magnetosomes isolated from Tieshan iron ore in Hubei Province of China  

Microsoft Academic Search

Several magnetotactic bacteria (MTB) have been isolated from iron cap belt, surface soil of intermediate belt and primary iron ore belt of Tieshan iron ore in Hubei Province, China. These magnetotactic bacteria were cultivated in enrichment medium at room temperature (2530 C), with oxygen concentration of 510% under the field of a permanent magnet. The magnetotactic bacteria were cocci or

Yanli Liu; Meiying Gao; Shunying Dai; Kefang Peng; Rongfen Jia

2006-01-01

83

Production of lightweight ceramisite from iron ore tailings and its performance investigation in a biological aerated filter (BAF) reactor.  

PubMed

The few reuse and large stockpile of iron ore tailings (IOT) led to a series of social and environmental problems. This study investigated the possibility of using the IOT as one of starting materials to prepare lightweight ceramisite (LWC) by a high temperature sintering process. Coal fly ash (CFA) and municipal sewage sludge (SS) were introduced as additives. The LWC was used to serve as a biomedium in a biological aerated filter (BAF) reactor for municipal wastewater treatment, and its purification performance was examined. The effects of sintering parameters on physical properties of the LWC, and leaching concentrations of heavy metals from the LWC were also determined. The microstructure and the phase composition of the LWC were analyzed by scanning electron microscopy (SEM) and X-ray diffraction (XRD). Results revealed that: (1) IOT could be used to produce the LWC under the optimal sintering parameters; (2) the leaching concentrations of heavy metals from the LWC were well below their respective regulatory levels in the China Environmental Quality Standards for Surface Water (CEQS); and (3) the BAF reactor with the LWC serving as the biomedium achieved high removal efficiencies for COD(Cr) (>92%), NH(4)(+)-N (>62%) and total phosphate (T-P) (>63%). Therefore, the LWC produced from the IOT was suitable to serve as the biomedium in the municipal wastewater treatment. PMID:20227178

Liu, Yangsheng; Du, Fang; Yuan, Li; Zeng, Hui; Kong, Sifang

2010-02-18

84

Characterization of haul road dust in an Indian opencast iron ore mine  

Microsoft Academic Search

Vehicular traffic on unpaved haul roads of the opencast mines has been identified as the most prolific source of fugitive dust. An intensive study was carried out in Noamundi Iron ore mines of Tata Iron and Steel Co. in JanuaryFebruary 1994 to characterize the airborne aerosol mainly contributed from unpaved haul road, traffic exhaust and re-entrained dust from the other

Subrato Sinha; S. P. Banerjee

1997-01-01

85

The search for asbestos within the Peter Mitchell Taconite iron ore mine, near Babbitt, Minnesota  

Microsoft Academic Search

Asbestos crystallizes within rock formations undergoing intense deformation characterized by folding, faulting, shearing, and dilation. Some of these conditions have prevailed during formation of the taconite iron ore deposits in the eastern Mesabi Iron Range of Minnesota. This range includes the Peter Mitchell Taconite Mine at Babbitt, Minnesota. The mine pit is over 8 miles long, up to 1 mile

Malcolm Ross; Robert P. Nolan; Gordon L. Nord

2008-01-01

86

The infrared spectra of amine collectors used in the flotation of iron ores  

Microsoft Academic Search

Inverse froth flotation is the most used concentration method for itabiritic iron ores, where the quartz gangue is floated, and the iron oxides are kept depressed by starches; medium-chain etheramine acetates are the cationic collectors used. Since there is a lack of thorough studies on the infrared spectroscopy of these reagents (and by other similar techniques), an investigation on the

R. M. F. Lima; P. R. G. Brandao; A. E. C. Peres

2005-01-01

87

Upgrading and dephosphorization of Western Australian iron ore using reduction roasting by adding sodium carbonate  

NASA Astrophysics Data System (ADS)

The technology of direct reduction by adding sodium carbonate (Na2CO3) and magnetic separation was developed to treat Western Australian high phosphorus iron ore. The iron ore and reduced product were investigated by optical microscopy and scanning electron microscopy. It is found that phosphorus exists within limonite in the form of solid solution, which cannot be removed through traditional ways. During reduction roasting, Na2CO3 reacts with gangue minerals (SiO2 and Al2O3), forming aluminum silicate-containing phosphorus and damaging the ore structure, which promotes the separation between iron and phosphorus during magnetic separation. Meanwhile, Na2CO3 also improves the growth of iron grains, increasing the iron grade and iron recovery. The iron concentrate, assaying 94.12wt% Fe and 0.07wt% P at the iron recovery of 96.83% and the dephosphorization rate of 74.08%, is obtained under the optimum conditions. The final product (metal iron powder) after briquetting can be used as the burden for steelmaking by an electric arc furnace to replace scrap steel.

Zhu, De-qing; Chun, Tie-jun; Pan, Jian; Lu, Li-ming; He, Zhen

2013-06-01

88

Morphological and mineralogical characterizations of oolitic iron ore in the Exi region, China  

NASA Astrophysics Data System (ADS)

The morphological and mineralogical characterizations of a Chinese oolitic iron ore (Exi deposit) were studied by scanning electron microscopy and energy-dispersive X-ray spectroscopy in this work. It is shown that the Exi ore is mainly composed of hematite, quartz, apatite, and chlorite. The hematite is present as the oolitic layers and in the spaces between the aggregated ooids; quartz exists as granular particles in the spaces and as nucleuses in ooids; the harmful mineral, apatite, is associated with hematite as the oolitic layers, fine dissemination, granular particles in the spaces, and nucleuses in ooids. From the viewpoint of mineral beneficiation, it is hard to separate apatite and chlorite but easy to separate quartz from hematite in the Exi iron ore in recovering the iron values.

Song, Shao-xian; Campos-Toro, Ernesto Fabian; Zhang, Yi-min; Lopez-Valdivieso, Alejandro

2013-02-01

89

Prospects for the 2020 Iron Ore Market.Quantitative Analysis of Market Dynamics and Risk Mitigation Strategies  

Microsoft Academic Search

As the key ingredient for steelmaking, iron ore is integral to the global economy and represents the world's second-largest natural resource market by value. The overall structure and dynamics of the iron ore market have recently undergone various radical changes. The global demand shock caused by the rapid industrialization of China has sent market prices skywards and triggered a collapse

Marc P. Bielitza

90

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.  

Code of Federal Regulations, 2010 CFR

...loss upon the disposal of coal or domestic iron ore with a retained economic interest...loss upon the disposal of coal or domestic iron ore with a retained economic interest...disposes of coal (including lignite), or iron ore mined in the United States,...

2010-04-01

91

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.  

Code of Federal Regulations, 2010 CFR

...loss upon the disposal of coal or domestic iron ore with a retained economic interest...loss upon the disposal of coal or domestic iron ore with a retained economic interest...disposes of coal (including lignite), or iron ore mined in the United States,...

2009-04-01

92

What determines productivity? lessons from the dramatic recovery of the U.S. and Canadian iron-ore industries following their early 1980s crisis  

Microsoft Academic Search

Great Lakes iron ore producers had faced no competition from foreign iron ore in the Great Lakes steel market for nearly a century as the 1970s closed. In the early 1980s, as a result of unprecedented developments in the world steel market, Brazilian producers were offering to deliver iron ore to Chicago (the heart of the Great Lakes market) at

James A. Schmitz Jr.

2005-01-01

93

Process for exploitation of low grade oxidic and iron-bearing complex ores or concentrates  

US Patent & Trademark Office Database

A process for the exploitation of low-grade oxidic and iron-bearing complex ores or concentrates, whereby the initial materials are reduced in a rotary kiln at a temperature of 1000.degree.-1500.degree. C. in such a manner that the products are a magnetic fraction primarily consisting of iron, and a non-magnetic oxide fraction, the materials present in this fraction being further exploitable by conventional methods.

1988-04-26

94

Direct iron ore reduction by methane in a fluidized bed. Final report, November 1989-December 1992  

SciTech Connect

Novel process chemistry of methane in a fluidized bed was investigated to identify a more direct route to producing the reducing gas needed in the Direct Reduction of iron ore. A rather surprising result, however, of the study was the discovery of an inexpensive and attrition-resistant catalytic material for methane oxidative coupling. The iron oxide impregnated, non-porous silica oxide was found to be relatively active, and quite selective when steam was added to the methane/air feed.

van der Vaart, D.R.; Conger, W.L.

1993-08-01

95

Sampling, Characterization, and Evaluation of Midwest Clays for Iron Ore Pellet Bonding.  

National Technical Information Service (NTIS)

The potential of using glacial lake clay from Minnesota, as well as other areas, as a binder for iron ore pellets was investigated. The best clay-characterizing procedures for predicting binder effectiveness were the cation exchange capacity using the met...

L. A. Haas J. A. Aldinger R. L. Blake S. A. Swan

1987-01-01

96

Testing of Northern Michigan and Wisconsin Glacial Lake Clays for Utilization as Iron Ore Pellet Binder.  

National Technical Information Service (NTIS)

Glacial lake clay deposits in northern Michigan and Wisconsin were sampled, tested and found to be unsuited for use as a bonding agent in iron ore pellet manufacturing. Although the project effort gave negative results, this report has been prepared to de...

W. S. Miska

1968-01-01

97

Influence of surfactants on filter cake parameters during vacuum filtration of flocculated iron ore sludge  

Microsoft Academic Search

The influence of certain surfactants on the dewatering of fine iron ore sludge flocculated with anionic flocculants has been investigated in a laboratory-scale vacuum filtration unit. The filtration data have been used in calculating the cake parameters from an integrated form of Darcy's law. A narrow concentration range of surfactant enables reduction of the specific cake resistance and an enhanced

L. Besra; B. P. Singh; P. S. R. Reddy; D. K. Sengupta

1998-01-01

98

Environmental impacts of iron ore tailingsThe case of Tolo Harbour, Hong Kong  

NASA Astrophysics Data System (ADS)

Disposal of iron ore tailings along the shore of Tolo Harbour, Hong Kong has altered the adjacent environment. Due to the ever-expanding population, the vast development of various industries, and the lack of sanitary control, the existing pollution problem of Tolo Harbour is serious. The iron ore tailings consist of a moderate amount of various heavy metals, e.g., copper, iron, manganese, lead, zinc, and a lower level of macronutrients. A few living organisms have been found colonizing this manmade habitat. Higher metal contents were also found in the tissue of Paphia sp. (clam); Scopimera intermedia (crab); Chaetomorpha brychagona (green alga); Enteromorpha crinita (green alga); and Neyraudia reynaudiana (grass). The area can be reclaimed by surface amelioration using inert materials, soils, or organic substrates, and by direct seeding, using nontolerant and tolerant plant materials. Reclamation of the tailings would improve the amenity of the adjacent environment and also mitigate pollution escaping to the sea.

Wong, M. H.

1981-03-01

99

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

SciTech Connect

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, 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.

De Michelis, Ida; Ferella, Francesco [University of L'Aquila, Department of Chemistry, Chemical Engineering and Materials, Monteluco di Roio, 67040 L'Aquila (Italy); Beolchini, Francesca [Polytechnic University of Marche, Department of Marine Sciences, Via Brecce Bianche, 60131 Ancona (Italy)], E-mail: f.beolchini@univpm.it; Veglio, Francesco [University of L'Aquila, Department of Chemistry, Chemical Engineering and Materials, Monteluco di Roio, 67040 L'Aquila (Italy)

2009-01-15

100

Technology of recovery of associated gold from Siberian iron ores  

Microsoft Academic Search

Conclusions\\u000a \\u000a \\u000a \\u000a 1.\\u000a \\u000a Skarn-magnetite ores of Siberia and wastes (rejects) of their treatment are a potential source of gold and other precious\\u000a components. Skarn-magnetite mineral associations, in particular, are characterized by low gold contents (hundredths of 1 g\\/ton).\\u000a Higher contents of noble metals are associated with superposed sulfide and quartz-vein mineralization (tenths of 1 g\\/ton and\\u000a less).\\u000a \\u000a \\u000a \\u000a \\u000a 2.\\u000a \\u000a From the point

A. S. Lapukhov; R. D. Mel'nikova; L. K. Pavlova; V. G. Petrov

1998-01-01

101

Solvent extraction of Fe(III) from the chloride leach liquor of low grade iron ore tailings using Aliquat 336  

Microsoft Academic Search

Solvent extraction of iron (III) from the HCl leach liquor of low grade iron ore tailings was studied with Aliquat 336, a quaternary amine in kerosene. p-Nonyl phenol was used as the third phase modifier. The effect of different parameters such as equilibration time, HCl concentration, H+ concentration, Cl? concentration and extractant concentration on extraction of iron was studied. The

R. K. Mishra; P. C. Rout; K. Sarangi; K. C. Nathsarma

2011-01-01

102

From Ore to Tool Iron Age Iron Smelting in the Largest and Oldest Meteorite Crater in the World  

NASA Astrophysics Data System (ADS)

The Vredefort Impact Structure in South Africa is the biggest and oldest remnant meteorite impact crater in the world where various ancient cultures thrived. In this paper some light will be shed on the Iron Age, iron smelting aspects of the people that inhabited the area and the results of a laboratory study of iron artefacts and a possible source of iron ore in the region is given. A sectional piece from a hoe manufactured in a small bloomery furnace was polished and etched and subsequently analyses with SEM and Mssbauer techniques were obtained. The hoe has a typical cast iron composition (2.9% C, 0.1% Mn, 0.4% Si, 0.4% P and 96.2% Fe, all wt.%) and contains many slag inclusions with wustite dendrites. The Mssbauer spectrum consisted of iron (86%), wustite (5%) and oxihydroxide (9%) and the thin (200 ?m) corrosion layer consisted of hematite (55%) and oxihydroxides (45%). At a furnace site, various slag clumps (26.3% C, 24.8% SiO2, 11.3% Al2O3, 1.3% P2O5, 1.0% K2O, 0.4% CaO and 30.2 FeO, all wt.%, average of four samples) and iron nodules (7.6% C, 6.0% Mn, 4.3% Si, 1.4% Al, 80.7% Fe, all wt.%) were found. The Mssbauer spectrum of the slag consisted of iron (7%), magnetite (56%), fayalite (2%) and oxihydroxides (35%) and that of the iron nodules yielded iron (28%), wustite (12%), magnetite (20%) and oxihydroxides (40%). A possible ore source containing 84% FeO, 7% of Al2O3 and SiO2 (all in wt.%) and minor impurities is located a few kilometers from the furnace site, yielding a Mssbauer spectrum consisting of hematite (70%) and oxihydroxides (30%).

Waanders, F. B.; Tiedt, L. R.; Brink, M. C.; Bisschoff, A. A.

2005-02-01

103

Upgrading of Low-Grade Manganese Ore by Selective Reduction of Iron Oxide and Magnetic Separation  

NASA Astrophysics Data System (ADS)

The utilization of low-grade manganese ores has become necessary due to the intensive mining of high-grade ores for a long time. In this study, calcined ferruginous low-grade manganese ore was selectively reduced by CO, which converted hematite to magnetite, while manganese oxide was reduced to MnO. The iron-rich component was then separated by magnetic separation. The effects of the various reduction parameters such as particle size, reduction time, temperature, and CO content on the efficiency of magnetic separation were studied by single-factor experiments and by a comprehensive full factorial experiment. Under the best experimental conditions tested, the manganese content in the ore increased from around 36 wt pct to more than 44 wt pct, and almost 50 wt pct of iron was removed at a Mn loss of around 5 pct. The results of the full factorial experiments allowed the identification of the significant effects and yielded regression equations for pct Fe removed, Mn/Fe, and pct Mn loss that characterize the efficiency of the upgrading process.

Gao, Yubo; Olivas-Martinez, M.; Sohn, H. Y.; Kim, Hang Goo; Kim, Chan Wook

2012-12-01

104

Magnetic properties of oolitic iron ore on Bell Island, Newfoundland  

Microsoft Academic Search

Magnetic properties of samples from Bell Island sedimentary rocks have been studied. X-ray analysis indicates that the main magnetic mineral is hematite in all samples. The other iron-bearing minerals identified are siderite and chamosite. Microscope observations of thin sections suggest that the rocks consist of oolitic hematite in a matrix of siderite or calcite. The intensity of natural remanent magnetization

. zdemir; E. R. Deutsch

1984-01-01

105

An ecological survey of the heavy metal contamination of the edible clam Paphia sp. on the iron-ore tailings of Tolo Harbour, Hong Kong  

Microsoft Academic Search

Iron-ore tailings have been deposited along the coast of Tolo Harbour from Ma On Shan Iron-ore Mine since its operation in 1906. In order to search for any harmful effects caused by the tailings, the edible clam, Paphia sp. together with sediments and seawater samples were collected from different sites of the iron-ore tailings of Ma On Shan Iron Mine,

Ming-Hung Wong; Mong-Wan Li

1977-01-01

106

Environmentally safe design of tailing dams for the management of iron ore tailings in Indian context.  

PubMed

The need for the disposal of iron ore tailings in an enviornmentally firiendly manner is of great concern. This paper investigates the soil engineering properties for the construction of iron ore tailing dam, its foundation, construction materials and design data used for the construction analysis of the tailing dam. Geophysical investigations were carried out to establish the bedrock below the spillway. A computer programme taking into account the Swedish Slip Circle Method of analysis was used in the stability analysis of dam. It also focuses on the charactierstics of the tailings reponsible for the determination of optimum size of tailing pond for the containment of the tailings. The studies on the settling characteristics of tailings indicate much less area in comparison to the area provided in the existing tailing ponds in India. In the proposed scheme, it is suggested to provide an additional unit of sedimentation tank before the disposal of tailings to the tailing pond. PMID:17051916

Ghose, Mrinal K; Sen, P K

2005-10-01

107

Reduction and Swelling of Fired Hematite Iron Ore Pellets by Non?coking Coal Fines for Application in Sponge Ironmaking  

Microsoft Academic Search

In the present investigation, the reduction and swelling behaviours (in low grade coal) of fired iron ore pellets, prepared by blending hematite iron ore fines of?100, ?18+25 and ?10+16 mesh sizes in different proportions, have been studied in the temperature range of 850C?1000C with an objective to promote massive utilization of fines in sponge ironmaking. An increase in temperature up

M. Kumar; H. Baghel; S. K. Patel

2012-01-01

108

Water resource accounting for an iron-ore mining area in India  

Microsoft Academic Search

A study has been conducted at the Bicholim iron-ore mine, North Goa, India to investigate the hydrogeological continuity\\u000a between the mine's open pit and surrounding villages. Water resource accounting by demarcating different watersheds has also\\u000a been carried out to analyse the major causes of groundwater scarcity in the region during dry periods. A resistivity survey\\u000a and a ground penetrating radar

S. K. Chaulya; M. K. Chakraborty; M. Ahmad; K. K. K. Singh; R. S. Singh; B. K. Tewary; P. K. Gupta

2000-01-01

109

Effects of iron-ore mining and processing on metal bioavailability in a tropical coastal lagoon  

Microsoft Academic Search

Background, aim, and scopeIn water systems, water quality and geochemical properties of sediments determine the speciation of trace metals, metal transport,\\u000a and sedimentwater exchange, influencing metal availability and its potential effects on biota. Studies from temperate climates\\u000a have shown that iron-ore mining and tailing wastewaters, besides being a source of trace metals, usually show high levels\\u000a of dissolved ions and

Adriana Alves Pereira; Bert van Hattum; Abraham Brouwer; Peter Michiel van Bodegom; Carlos Eduardo Rezende; Wim Salomons

2008-01-01

110

A dynamic mathematical model of the complete grate/kiln iron-ore pellet induration process  

NASA Astrophysics Data System (ADS)

Induration (drying and hardening) of iron ore pellets is an energy-intensive feed preparation step for both the blast furnace and direct reduction routes to iron. It is commonly carried out by a grate/kiln process. A mathematical model of the process is described, in which mechanistic models of the grate furnace, kiln, and cooler are linked to enable simulation of the entire process. The model includes equations for the gas stream pressure balances and process controller responses, and provides dynamic solutions. The validation of the model for an operating plant is discussed and steady-state solutions are compared with data from the plant.

Thurlby, J. A.

1988-02-01

111

Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills  

NASA Astrophysics Data System (ADS)

An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900 C for 60 minutes and given stepped austempering treatment at 280 C for 30 minutes and 60 minutes followed by 380 C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

Raghavendra, H.; Bhat, K. L.; Udupa, K. Rajendra; Hegde, M. M. Rajath

2011-01-01

112

Magmatic origin of giant 'Kiruna-type' apatite-iron-oxide ores in Central Sweden  

PubMed Central

Iron is the most important metal for modern industry and Sweden is by far the largest iron-producer in Europe, yet the genesis of Sweden's main iron-source, the Kiruna-type apatite-iron-oxide ores, remains enigmatic. We show that magnetites from the largest central Swedish Kiruna-type deposit at Grngesberg have ?18O values between ?0.4 and +3.7, while the 1.90?1.88?Ga meta-volcanic host rocks have ?18O values between +4.9 and +9. Over 90% of the magnetite data are consistent with direct precipitation from intermediate to felsic magmas or magmatic fluids at high-temperature (?18Omgt > +0.9, i.e. ortho-magmatic). A smaller group of magnetites (?18Omgt ? +0.9), in turn, equilibrated with high-?18O, likely meteoric, hydrothermal fluids at low temperatures. The central Swedish Kiruna-type ores thus formed dominantly through magmatic iron-oxide precipitation within a larger volcanic superstructure, while local hydrothermal activity resulted from low-temperature fluid circulation in the shallower parts of this system.

Jonsson, Erik; Troll, Valentin R.; Hogdahl, Karin; Harris, Chris; Weis, Franz; Nilsson, Katarina P.; Skelton, Alasdair

2013-01-01

113

Magmatic origin of giant 'Kiruna-type' apatite-iron-oxide ores in Central Sweden.  

PubMed

Iron is the most important metal for modern industry and Sweden is by far the largest iron-producer in Europe, yet the genesis of Sweden's main iron-source, the 'Kiruna-type' apatite-iron-oxide ores, remains enigmatic. We show that magnetites from the largest central Swedish 'Kiruna-type' deposit at Grngesberg have ?(18)O values between -0.4 and +3.7, while the 1.90-1.88?Ga meta-volcanic host rocks have ?(18)O values between +4.9 and +9. Over 90% of the magnetite data are consistent with direct precipitation from intermediate to felsic magmas or magmatic fluids at high-temperature (?(18)Omgt > +0.9, i.e. ortho-magmatic). A smaller group of magnetites (?(18)Omgt ? +0.9), in turn, equilibrated with high-?(18)O, likely meteoric, hydrothermal fluids at low temperatures. The central Swedish 'Kiruna-type' ores thus formed dominantly through magmatic iron-oxide precipitation within a larger volcanic superstructure, while local hydrothermal activity resulted from low-temperature fluid circulation in the shallower parts of this system. PMID:23571605

Jonsson, Erik; Troll, Valentin R; Hgdahl, Karin; Harris, Chris; Weis, Franz; Nilsson, Katarina P; Skelton, Alasdair

2013-04-10

114

26 CFR 1.631-3 - Gain or loss upon the disposal of coal or domestic iron ore with a retained economic interest.  

Code of Federal Regulations, 2013 CFR

...false Gain or loss upon the disposal of coal or domestic iron ore with a retained economic...631-3 Gain or loss upon the disposal of coal or domestic iron ore with a retained economic...c) apply to an owner who disposes of coal (including lignite), or iron...

2013-04-01

115

Processing of iron-titanium powder mixtures by transient liquid phase sintering  

NASA Astrophysics Data System (ADS)

Transient liquid phase sintering was examined for Fe-Ti powder mixtures. The experimental plan included the effects of several processing variables, such as green density, particle size, composition, heating rate, sintering temperature, and sintering time. During heating, pores form at the Ti particle sites. At the first eutectic temperature (1085 C), liquid spreading is inhibited by a surrounding intermetallic envelope, leading to swelling. At the second eutectic temperature (1289 C), the liquid penetrates along the iron grain boundaries and provides densification. The amount of densification depends on the amount of liquid formed at the second eutectic temperature and its duration as determined by the titanium content and heating rate.

German, R. M.; Dunlap, J. W.

1986-02-01

116

Origin and significance of aromatic hydrocarbons in giant iron ore deposits of the late Archean Hamersley Basin, Western Australia  

Microsoft Academic Search

Late Archean to earliest Paleoproterozoic shales associated with two giant iron ore deposits in the Hamersley Province, Western Australia, contain traces of solvent extractable saturated and aromatic hydrocarbons. The host rocks belong to the ?2.5 billion years (Ga) old Mt McRae Shale and Brockman Iron Formation, Hamersley Group, and were collected in mines near Tom Price and Newman (Mt Whaleback).

Jochen J. Brocks; Roger E. Summons; Roger Buick; Graham A. Logan

2003-01-01

117

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

NASA Astrophysics Data System (ADS)

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 1300C) reduction of nickeliferous laterite ores followed by magnetic separation could provide an alternative avenue without smelting at high temperature (~1500C) for producing ferronickel with low cost, the fundamentals and recent developments of the low-temperature reduction of nickeliferous laterite ores are reviewed.

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

2013-09-01

118

Elemental analysis of some Egyptian ores and industrial iron samples by neutron activation analysis.  

PubMed

Elemental analysis of iron ore samples and first industrial iron production prepared by the Egyptian Iron and Steel Company of Helwan near Cairo were determined by instrumental neutron activation analysis technique. Five samples from each kind were irradiated for a 48 hours at a thermal neutron flux of 4 x 10(12) n/(cm2.s) in the first Egyptian research reactor ET-RR-1. Also the Pneumatic irradiation Rabbit system (PIRS) attached to the reactor in Inshass, was used to measure the elements of short-life time. The gamma-ray spectra were recorded by means of the hyper pure germanium detection system. The concentration percentage values of major, minor and trace elements are presented. The long and short lived isotopes were considered. A comparative study and a discussion on the elemental concentration values are given. PMID:11590711

Srror, A; Abdel-Basset, N; Abdel-Haleem, A S; Hassan, A M

2001-01-01

119

Method and particle mixture for making rare earth element, iron and boron permanent sintered magnets  

SciTech Connect

This patent describes a method for producing sintered permanent magnets of a permanent magnet alloy comprising a rare earth element, iron and boron. It comprises providing a permanent magnet, rare earth element, iron and boron alloy material dross alloy and up to 6% scrap alloy; dross alloy and virgin alloy; and dross alloy and virgin alloy and greater than 0 to 80% scrap alloy, sequentially hydrating the material in a hydrogen atmosphere to hydride and decreptitate the material to form particles therefrom, reducing the size of the particles, compacting the particles and dehydrating and sintering the particles to produce a substantially fully dense article for use as a permanent magnet.

Kim, A.S.

1992-02-25

120

Sintering.  

National Technical Information Service (NTIS)

The results of experimental and theoretical investigations of the sintering process in crystalline solids are reviewed in a primarily pedagogical manner. Emphasis is placed on elucidating the origin of the driving force for the process and the mass flow m...

J. E. Burke J. H. Rosolowski

1973-01-01

121

Recovery Behavior of Rare Earth from Bayan Obo Complex Iron Ore  

NASA Astrophysics Data System (ADS)

A novel process is presented for recovering rare earth from Bayan Obo complex iron ore. The iron ore was reduced and melting separated to produce iron nugget and rare-earth-rich slag. In order to investigate the influence of cooling rate on mineral components, especially the enrichment behavior of RE-containing mineral, the slag was remelted at 1673 K (1400 C) and the liquid slags were cooled using three types of cooling conditions, water quenching, air cooling, and furnace cooling. Subsequently, the slags were leached by hydrochloric acid to evaluate the relations between leaching efficiency of rare earth and cooling conditions. The results indicated that the slags under different cooling conditions mainly contained fluorite, cefluosil, and cuspidine. The rare-earth mineral is more fully crystallized when the cooling rate of the liquid slag was decreased. The proportion of Ce (III) to Ce (IV) increases with the increase of heating time and decrease of cooling rate. It has been found that the influence of cooling rate on the leaching rate of the rare earth is slight. From water quenching to furnace cooling, the leaching rate of rare earth increases from 97.00 pct to 99.48 pct. After being filtered, filtrate can be used to produce rare-earth chloride. Leached residue, with CaF2 of 64.45 pct and ThO2 of 0.05 pct, can be used to recover CaF2 and extract nuclear source material.

Ding, Yingui; Xue, Qingguo; Wang, Guang; Wang, Jingsong

2013-02-01

122

Low cost improvements in air pollution control for ARMCO's Ashland, Kentucky Works Sinter Plant  

SciTech Connect

Particulate emissions from sinter plants can contribute a significant percentage of the total emissions from integrated steelmaking facilities. A well-known sinter plant air pollution phenomenon is called blue haze emissions. These emissions are caused when hydrocarbons introduced by filter cake, coke breeze, and mill scale are not burned in the sintering process and pass through the system as a very finely divided stable dispersed fog. The Sinter Plant at Ashland Works consists of Dravo-Lurgi traveling grate sintering machine which processes a mixture of materials including iron ore, iron pellet fines, blast furnace flue dust, limestone, melt shop slag, coke breeze and sinter return fines. This system is illustrated by the authors. Upon completion of the sintering process, the hot agglomerated sinter product is discharged to the sinter crusher. The sinter is then cooled and screened for use in Ashland Works' Amanda Blast Furnace. This system is illustrated. The Ashland Works Sinter Plant complex consists of a Sintering Machine Building, Sinter Screens Building and Ore Screens Building. For the purposes of this study, the Ore Transfer Tower Building was also included. The general layout of the complex is illustrated.

Felton, S.S. (ARMCO Inc., Ashland, KY (US))

1987-01-01

123

Pressurized chemical-looping combustion of coal with an iron ore-based oxygen carrier  

SciTech Connect

Chemical-looping combustion (CLC) is a new combustion technology with inherent separation of CO{sub 2}. Most of the previous investigations on CLC of solid fuels were conducted under atmospheric pressure. A pressurized CLC combined cycle (PCLC-CC) system is proposed as a promising coal combustion technology with potential higher system efficiency, higher fuel conversion, and lower cost for CO{sub 2} sequestration. In this study pressurized CLC of coal with Companhia Valedo Rio Doce (CVRD) iron ore was investigated in a laboratory fixed bed reactor. CVRD iron ore particles were exposed alternately to reduction by 0.4 g of Chinese Xuzhou bituminous coal gasified with 87.2% steam/N{sub 2} mixture and oxidation with 5% O{sub 2} in N{sub 2} at 970 C. The operating pressure was varied between 0.1 MPa and 0.6 MPa. First, control experiments of steam coal gasification over quartz sand were performed. H{sub 2} and CO{sub 2} are the major components of the gasification products, and the operating pressure influences the gas composition. Higher concentrations of CO{sub 2} and lower fractions of CO, CH{sub 4}, and H{sub 2} during the reduction process with CVRD iron ore was achieved under higher pressures. The effects of pressure on the coal gasification rate in the presence of the oxygen carrier were different for pyrolysis and char gasification. The pressurized condition suppresses the initial coal pyrolysis process while it also enhances coal char gasification and reduction with iron ore in steam, and thus improves the overall reaction rate of CLC. The oxidation rates and variation of oxygen carrier conversion are higher at elevated pressures reflecting higher reduction level in the previous reduction period. Scanning electron microscope and energy-dispersive X-ray spectroscopy (SEM-EDX) analyses show that particles become porous after experiments but maintain structure and size after several cycles. Agglomeration was not observed in this study. An EDX analysis demonstrates that there is very little coal ash deposited on the oxygen carrier particles but no appreciable crystalline phases change as verified by X-ray diffraction (XRD) analysis. Overall, the limited pressurized CLC experiments carried out in the present work suggest that PCLC of coal is promising and further investigations are necessary. (author)

Xiao, Rui; Song, Min; Zhang, Shuai; Shen, Laihong [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); Song, Qilei [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); Department of Chemical Engineering and Biotechnology, University of Cambridge, Pembroke Street, Cambridge CB2 3RA (United Kingdom); Lu, Zuoji [School of Energy and Environment, Southeast University, Sipailou No. 2, Nanjing 210096 (China); GCL Engineering Limited, Zhujiang No. 1, Nanjing 210008 (China)

2010-06-15

124

Uraniumlead ages of apatite from iron oxide ores of the Bafq District, East-Central Iran  

Microsoft Academic Search

Iron oxideapatite (IOA) deposits, often referred to as Kiruna-type iron ore deposits, are known to have formed from the Proterozoic\\u000a to the Tertiary. They are commonly associated with calcalkaline volcanic rocks and regional- to deposit-scale metasomatic\\u000a alteration. In the Bafq District in east Central Iran, economic iron oxideapatite deposits occur within felsic volcanic tuffs\\u000a and volcanosedimentary sequences of Early Cambrian

Heinz-Gnter Stosch; Rolf L. Romer; Farahnaz Daliran; Dieter Rhede

2011-01-01

125

Standard test method for aluminum in iron ores by complexometric titration  

SciTech Connect

This method covers the determination of aluminum in iron ores, concentrates, and agglomerates in the concentration range from 0.25 to 5% aluminium. The sample is fused in a zirconium crucible with a mixed flux of sodium carbonate and sodium peroxide. The fused mass is dissolved in dilute hydrochloric acid. The R/sub 2/O/sub 3/ hydroxides are precipitated with ammonia and redissolved in hydrochloric acid. Iron, titanium, etc., are removed with cupferron and chloroform. The aqueous phase is treated with nitric and perchloric acids and evaporated to dryness. After dissolving in dilute hydrochloric acid, the solution is filtered, and the filtrate is treated with an excess of ethylenediaminetetraacetic acid (EDTA). The excess EDTA is titrated with a standard zinc solution using xylenol orange indicator. Ammonium fluoride is added to release the EDTA bound to aluminum. This EDTA is then titrated with standard zinc solution, and the percent aluminum is calculated.

Not Available

1980-01-01

126

Airway inflammation in iron ore miners exposed to dust and diesel exhaust.  

PubMed

The aim of the present study was to investigate if underground miners exposed to dust and diesel exhaust in an iron ore mine would show signs of airway inflammation as reflected in induced sputum. In total, 22 miners were studied, once after a holiday of at least 2 weeks and the second time after 3 months of regular work. Control subjects were 21 "white-collar" workers. All subjects completed a questionnaire regarding medical and occupational history, and underwent lung function testing and induced sputum collection. Total and differential cell counts and analyses of the fluid phase of the induced sputum were performed. Sampling of personal exposure to elemental carbon, nitrogen dioxide and inhalable dust was recorded. The average concentrations of inhalable dust, nitrogen dioxide and elemental carbon were 3.2 mg.m-3, 0.28 mg.m-3 and 27 microg.m-3, respectively. Miners had increased numbers of inflammatory cells, mainly alveolar macrophages and neutrophils, and increased concentrations of fibronectin, metalloproteinase-9 and interleukin-10 in induced sputum compared with controls. In conclusion, miners in an underground iron ore mine demonstrated persistent airway inflammation that was as pronounced after a 4-week holiday as after a 3-month period of work underground in the mine. PMID:16455836

Adelroth, E; Hedlund, U; Blomberg, A; Helleday, R; Ledin, M-C; Levin, J O; Pourazar, J; Sandstrm, T; Jrvholm, B

2006-02-02

127

Rock Magnetic and Oxide Microscopy Studies of two South American Iron-Ore Deposits  

NASA Astrophysics Data System (ADS)

Microscopy and rock-magnetic studies of the iron oxide-ore and host rocks in the Cristales-Pleito Melon (Chile) and Jacupiranga (Brazil) deposits were carried out to characterize and compare the magnetic mineralogy and the processes that affected the natural remanent magnetization (NRM) during emplacement and evolution of the iron-ore deposits. The microscopy study under reflected light shows that magnetic carriers are mainly magnetites, with minor amounts of ilmenite-hematite minerals. Titanomagnetite, shows trellis texture, which is compatible with high temperature oxy-exsolution processes. Grain sizes range from a few microns to >100 µm, and dominant magnetic state pseudo-single-domain, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and isothermal remanent magnetization (IRM) acquisition suggest a predominance of some spinels (titanomagnetite or titanomaghemite) with low-Ti content as magnetic carriers. These data help to investigate the magnetic domain states and the remanence acquisition processes, and to assess their significance as a source of magnetic anomalies.

Alva-Valdivia, L. M.

2005-05-01

128

Are metal mining effluent regulations adequate: identification of a novel bleached fish syndrome in association with iron-ore mining effluents in Labrador, Newfoundland  

Microsoft Academic Search

Water quality guidelines for industrial effluents are in place in many countries but they have generally evolved within a limited ecotoxicological framework. Effluents from iron-ore mines have traditionally been viewed by regulatory bodies as posing little or no risk to the aquatic environment. However, it was recently reported that lake trout taken from a large iron-ore contaminated Lake in Labrador

J. F. Payne; D. Hamoutene; P. Yeats; A. Rahimtula; D. Scruton; C. Andrews

2001-01-01

129

Comprehensive analysis of slope stability and determination of stable slopes in the Chador-Malu iron ore mine using numerical and limit equilibrium methods  

Microsoft Academic Search

One of the critical aspects in mine design is slope stability analysis and the determination of stable slopes. In the Chador-Malu iron ore mine, one of the most important iron ore mines in central Iran, it was considered vital to perform a comprehensive slope stability analysis. At first, we divided the existing rock hosting pit into six zones and a

M ATAEI; S BODAGHABADI

2008-01-01

130

Grinding Wear Behaviour of Stepped Austempered Ductile Iron as Media Material During Comminution of Iron Ore in Ball Mills  

SciTech Connect

An attempt has been made to evaluate the suitability of austempered ductile iron (ADI) as media material for grinding iron ore in a ball mill. Spheroidal graphite (S.G) iron balls are austenitised at 900 deg. C for 60 minutes and given stepped austempering treatment at 280 deg. C for 30 minutes and 60 minutes followed by 380 deg. C for 60 minutes in each case. These materials are characterised by measuring hardness, analysing X-ray diffraction (X-RD), studying microstructure using optical and scanning electron microscope (SEM). Grinding wear behaviour of these materials was assessed for wear loss in wet condition at different pH value of the mineral slurry and found that the wear rate of grinding media material decreases with increase in pH of the slurry. The wear resistance of ADI balls were compared with forged En31 steel balls and found that the stepped austempered ductile iron is superior to forged En31 steel balls.

Raghavendra, H. [Research scholar, Department of Metallurgical and Materials Engineering, N.I.T.K., Surathkal (India); Bhat, K. L.; Udupa, K. Rajendra [Professor, Department of Metallurgical and Materials Engineering, N.I.T.K., Surathkal (India); Hegde, M. M. Rajath [Research Scholar, Institute for Technology Research and Innovation (ITRI), Geelong Technology Precinct (GTP), Waurn Ponds, Victoria 3216 (Australia)

2011-01-17

131

Multiple reaction fronts in the oxidation-reduction of iron-rich uranium ores  

SciTech Connect

When a container of radioactive waste is buried underground, it eventually corrodes, and leakage of radioactive material to the surrounding rock occurs. Depending on the chemistry of the rock, many different reactions may occur. A particular case concerns the oxidation and reduction of uranium ores by infiltrating groundwater, since UO[sub 3] is relatively soluble (and hence potentially transportable to the water supply), whereas UO[sub 2] is essentially insoluble. It is therefore of concern to those involved with radioactive waste disposal to understand the mechanics of uranium transport through reduction and oxidation reactions. This paper describes the oxidation of iron-rich uranium-bearing rocks by infiltration of groundwater. A reaction-diffusion model is set up to describe the sequence of reactions involving iron oxidation, uranium oxidation and reduction, sulfuric acid production, and dissolution of the host rock that occur. On a geological timescale of millions of years, the reactions occur very fast in very thin reaction fronts. It is shown that the redox front that separates oxidized (orange) rock from reduced (black) rock must actually consist of two separate fronts that move together, at which the two separate processes of uranium oxidation and iron reduction occur, respectively. Between these fronts, a high concentration of uranium is predicted. The mechanics of this process are not specific to uranium-mediated redox reactions, but apply generally and may be used to explain the formation of concentrated ore deposits in extended veins. On the long timescales of relevance, a quasi-static response results, and the problem can be solved explicitly in one dimension. This provides a framework for studying more realistic two-dimensional problems in fissured rocks and also for the future study of uraninite nodule formation.

Dewynne, J.N. (Univ. of Southampton (United Kingdom). Faculty of Mathematical Studies); Fowler, A.C. (Oxford Univ. (United Kingdom). Mathematical Inst.); Hagan, P.S. (Los Alamos National Lab., NM (United States))

1993-08-01

132

Phytoremediation: a novel approach for utilization of iron-ore wastes.  

PubMed

Large quantities of iron-ore tailings are being generated annually in the world from mining and processing of iron ores. It has been estimated that around 10-15% of the iron ore mined in India has remained unutilized and discarded as slimes during mining and subsequent processing. Soil contamination resulting from mining activities affects surrounding flora and fauna and presents a large clean-up challenge to the mining industry. Innovative new methodologies have been proposed and among the most promising are those that rely on new phytoremediation technology. In this paper we address and review the status of phytoremediation as a technology to reduce and control contaminated mine wastes. Several different approaches and different plant species are used to remove environmentally toxic metals from mine waste sites. Such approaches have the objective of restoring mining waste sites to human and animal use, or at least, to curtail or eliminate the off-site movement of toxic entities that potentially could reach humans. How well phytoremediation performs as an alternative soil restoration technology depends on several factors, including the composition of soil, toxicity level of the contaminant, degree to which plant species fit natural local growth patterns and type of concentration of metal/contaminant in such plants. Phytoremediation has opened prospects for less costly, yet practicable approaches to clean-up contaminated waste sites, particularly those associated with mineral extraction mining. We discuss several plant species that are capable of phytoextracting and/or phytostabilizing harmful elements from contaminated soil and water; such processes are prospectively effective for addressing waste problems that derive from mining and processing activities, as well as those that derive from mitigating the threat posed by waste that surrounds mining sites. Unfortunately, phytoremediation is still in the embryonic stage, and more research is needed to find the plant species that will be most effective for addressing different mining waste scenarios. Such plants must be able to survive and even thrive in heavily contaminated soil and be able to mitigate the pollutants that exist in the soil in which these plants will grow. PMID:20652667

Mohanty, Monalisa; Dhal, Nabin Kumar; Patra, Parikshita; Das, Bisweswar; Reddy, Palli Sita Rama

2010-01-01

133

Silicosis in the iron-ore mine in Kiruna, Sweden, and the future need for silicosis control  

Microsoft Academic Search

From 1931 to 1977 a total of 144 cases of silicosis have been diagnosed in the iron-ore mine in Kiruna, Sweden. Drilling, loading and tapping caused all cases of silicosis. In 24% of the cases, the disease had progressed after the diagnosis. The progression of the disease after diagnosis showed no significant correlation to the length of the exposure but

Harold Sihm Jrgensen

1986-01-01

134

Preparation, electrical and photoelectrochemical properties of magnesium doped iron oxide sintered discs  

SciTech Connect

Sintered discs of magnesium substituted iron oxides have been prepared by gel routes or classical solid state reaction techniques and their crystallographic, electrical, and photoelectrochemical properties examined. The discs, sintered between 1200 and 1400/sup 0/C for 20 hours, contain both ..alpha..-Fe/sub 2/O/sub 3/ and a spinel phase. The electrical properties of the discs have been correlated with spinel concentration, the electrical resistivity decreasing with increasing spinel content. The materials were found to be consistently n-type by Seebeck voltage measurements. Photoelectrochemical measurements in aqueous solution showed, however, that the sintered disc electrodes exhibit photocathodic currents that are characteristic of p-type semiconductors. Evidence is presented which suggests that inhomogeneities in the near surface region of the discs are responsible for the observed photoelectrochemical properties.

Sieber, K.D.; Sanchez, C.; Turner, J.E.; Somorjai, G.A.

1985-01-01

135

A risk assessment for exposure to grunerite asbestos (amosite) in an iron ore mine  

PubMed Central

The potential for health risks to humans exposed to the asbestos minerals continues to be a public health concern. Although the production and use of the commercial amphibole asbestos mineralsgrunerite (amosite) and riebeckite (crocidolite)have been almost completely eliminated from world commerce, special opportunities for potentially significant exposures remain. Commercially viable deposits of grunerite asbestos are very rare, but it can occur as a gangue mineral in a limited part of a mine otherwise thought asbestos-free. This report describes such a situation, in which a very localized seam of grunerite asbestos was identified in an iron ore mine. The geological occurrence of the seam in the ore body is described, as well as the mineralogical character of the grunerite asbestos. The most relevant epidemiological studies of workers exposed to grunerite asbestos are used to gauge the hazards associated with the inhalation of this fibrous mineral. Both analytical transmission electron microscopy and phase-contrast optical microscopy were used to quantify the fibers present in the air during mining in the area with outcroppings of grunerite asbestos. Analytical transmission electron microscopy and continuous-scan x-ray diffraction were used to determine the type of asbestos fiber present. Knowing the level of the miners exposures, we carried out a risk assessment by using a model developed for the Environmental Protection Agency.

Nolan, R. P.; Langer, A. M.; Wilson, Richard

1999-01-01

136

Iron ore beneficiation using roll-type high-intensity electric field separators  

SciTech Connect

This paper aims to demonstrate that high-intensity electric fields can be employed for the separation of artificial magnetite processed from an iron mineral containing siderite FeCO{sub 3} and ankerite (FeCaMg)CO{sub 3}. All the tests were carried out on a roll-type laboratory separator (roll diameter: 250 mm; roll speed: 175 r/min), provided with an over-tray heater, to ensure the thermal conditioning of the samples at +120 C, and a system of high-voltage electrodes, consisting of a needle-type corona electrode and either a second corona electrode or a tubular (electrostatic) electrode. The samples were collected from the technological process presently employed for the beneficiation of the iron ore deposit at Teliuc, Romania. The grain size was typically in the 0.09--0.315-mm range. Separation in high-intensity electric field ensured the increase of the Fe content in the samples from about 35--55%, for an iron recovery of up to 80%. This paper discusses these results in relation to the mineralogical characteristics of the samples and concludes that electrostatic separation could be employed either as an additional operation in an existing technological process, or as an alternative to the currently employed magnetic separation. Pilot-plant tests are needed prior to industry application.

Morar, R.; Iuga, A.; Muntean, O. [Technical Univ. of Cluj-Napoca (Romania). Electrical Engineering Dept.; Cuglesan, I. [Inst. of Research and Development for the Mining Industry, Cluj-Napoca (Romania); Dascalescu, L. [Inst. Univ. de Technologie d`Angouleme (France). Lab. de Technologies Electriques et Electroniques Avancees

1999-01-01

137

Beneficiation of iron ore slime using Aspergillus niger and Bacillus circulans.  

PubMed

Studies were carried out on the removal of alumina from iron ore slime containing (%) Fe(2)O(3) 75.7, Al(2)O(3) 9.95, SiO(2) 6.1, Fe (total) 52.94 with the help of Bacillus circulans and Aspergillus niger. B. circulans and A. niger showed 39% and 38% alumina removal after six and 15 days of in situ leaching at 10% pulp density, respectively. Culture filtrate leaching with A. niger removed 20% alumina at 2% pulp density with 13 day old culture filtrate. B. circulans was more efficient than A. niger for selective removal of alumina. In case of A. niger in situ leaching rather than culture filtrate leaching was found to be more effective. PMID:16531043

Pradhan, N; Das, B; Gahan, C S; Kar, R N; Sukla, L B

2006-03-13

138

Characteristics of iron ore tailing slime in India and its test for required pond size.  

PubMed

The physical and chemical nature of the tailing slime depends on milling operations and water content in the effluent. The characteristics of the tailings dictate the type of disposal facility required. Characteristics of the tailings, transportation from beneficiation plants and disposal system are described. Studies on tailing slime have been carried out at iron ore mines in Orissa and the results are discussed. The tailings contain toxic elements and find their way into the water environment. Sedimentation test was carried out on tailings and the area required for tailing pond was found to be 3155 m2 in comparison to 10000 m2 obtained from the use of an empirical equation. Provision of tailing pond for the disposal of tailings is a conservation of resources in addition to pollution control, and sedimentation test is essential for required pond size calculation. PMID:11336411

Ghose, M K; Sen, P K

2001-04-01

139

Direct observation of liquid-phase sintering in the system iron-copper  

Microsoft Academic Search

The hot-stage of a scanning electron microscope has been used to observe liquid-phase sintering in the system iron-copper. The densification behaviour of compacts of Fe and Cu particles were determined. The influence of particle size of both components and the amount of liquid phase developed were investigated. In samples with about 20 vol % liquid phase, the densification kinetics as

Leonhard Froschauer; Richard M. Fulrath

1975-01-01

140

Microstructure and tensile properties of liquid-phase-sintered tungsten-nickel-iron composites  

Microsoft Academic Search

An optimum processing cycle was developed and applied to a series of tungsten heavy alloys containing 88 to 97 wt.% tungsten with a nickel-to-iron ratio of 7:3 by weight. The alloys had sintered densities that approached the theoretical values and exhibited excellent bonding between the tungsten grains and the matrix. Microstructural characterization involved determination of the volume fractions, dihedral angles,

Rabin

1986-01-01

141

Using oxygen isotope chemistry to track hydrothermal processes and fluid sources in itabirite-hosted iron ore deposits in the Quadriltero Ferrfero, Minas Gerais, Brazil  

NASA Astrophysics Data System (ADS)

The Quadriltero Ferrfero, Brazil, is presently the largest accumulation of single itabirite-hosted iron ore bodies worldwide. Detailed petrography of selected hypogene high-grade iron ore bodies at, e.g. the guas Claras, Conceio, Pau Branco and Pico deposits revealed different iron oxide generations, from oldest to youngest: magnetite ? martite (hematite pseudomorph after magnetite) ? granoblastic (recrystallised) ? microplaty (fine-grained, <100 ?m) ? specular (coarse-grained, >100 ?m) hematite. Laser-fluorination oxygen isotope analyses of selected iron ore species showed that the ?18O composition of ore-hosted martite ranges between -4.4 and 0.9 and is up to 11 depleted in 18O relative to hematite of the host itabirite. During the modification of iron ore and the formation of new iron oxide generations (e.g. microplaty and specular hematite), an increase of up to 8 in ?18O values is recorded. Calculated ?18O values of hydrothermal fluids in equilibrium with the iron oxide species indicate: (1) the involvement of isotopically light fluids (e.g. meteoric water or brines) during the upgrade from itabirite-hosted hematite to high-grade iron ore-hosted martite and (2) a minor positive shift in ?18Ofluid values from martite to specular hematite as result of modified meteoric water or brines with slightly elevated ?18O values and/or the infiltration of small volumes of isotopically heavy (metamorphic and/or magmatic) fluids into the iron ore system. The circulation of large fluid volumes that cause the systematic decrease of 18O/16O ratios from itabirite to high-grade iron ore requires the presence of, e.g. extensive faults and/or large-scale folds.

Hensler, Ana-Sophie; Hagemann, Steffen G.; Brown, Philip E.; Rosire, Carlos A.

2013-10-01

142

Ferrous Iron and Sulfur Oxidation and Ferric Iron Reduction Activities of Thiobacillus ferrooxidans Are Affected by Growth on Ferrous Iron, Sulfur, or a Sulfide Ore  

PubMed Central

Eight strains of Thiobacillus ferrooxidans (laboratory strains Tf-1 [= ATCC 13661] and Tf-2 [= ATCC 19859] and mine isolates SM-1, SM-2, SM-3, SM-4, SM-5, and SM-8) and three strains of Thiobacillus thiooxidans (laboratory strain Tt [= ATCC 8085] and mine isolates SM-6 and SM-7) were grown on ferrous iron (Fe2+), elemental sulfur (S0), or sulfide ore (Fe, Cu, and Zn). The cells were studied for their aerobic Fe2+ - and S0-oxidizing activities (O2 consumption) and anaerobic S0-oxidizing activity with ferric iron (Fe3+) (Fe2+ formation). Fe2+-grown T. ferrooxidans cells oxidized S0 aerobically at a rate of 2 to 4% of the Fe2+ oxidation rate. The rate of anaerobic S0 oxidation with Fe3+ was equal to the aerobic oxidation rate in SM-1, SM-3, SM-4, and SM-5, but was only one-half or less that in Tf-1, Tf-2, SM-2, and SM-8. Transition from growth on Fe2+ to that on S0 produced cells with relatively undiminished Fe2+ oxidation activities and increased S0 oxidation (both aerobic and anaerobic) activities in Tf-2, SM-4, and SM-5, whereas it produced cells with dramatically reduced Fe2+ oxidation and anaerobic S0 oxidation activities in Tf-1, SM-1, SM-2, SM-3, and SM-8. Growth on ore 1 of metal-leaching Fe2+-grown strains and on ore 2 of all Fe2+-grown strains resulted in very high yields of cells with high Fe2+ and S0 oxidation (both aerobic and anaerobic) activities with similar ratios of various activities. Sulfur-grown Tf-2, SM-1, SM-4, SM-6, SM-7, and SM-8 cultures leached metals from ore 3, and Tf-2 and SM-4 cells recovered showed activity ratios similar to those of other ore-grown cells. It is concluded that all the T. ferrooxidans strains studied have the ability to produce cells with Fe2+ and S0 oxidation and Fe3+ reduction activities, but their levels are influenced by growth substrates and strain differences.

Suzuki, Isamu; Takeuchi, Travis L.; Yuthasastrakosol, Trin D.; Oh, Jae Key

1990-01-01

143

Active and passive behavior of sintered iron in ammoniacal ammonium carbonate solution  

NASA Astrophysics Data System (ADS)

The anodic dissolution behavior of sintered iron in ammoniacal ammonium carbonate solution (pH = 9.7) has been investigated with the aid of electrochemical techniques. Surface films formed on bulk iron during air exposure or immersion in the ammoniacal solution were characterized by using X-ray photoelectron spectroscopy (XPS). Immersion in the ammoniacal solution gave an apparent open circuit potential (OCP) in the range of E = 0.04 to 0.09 V, standard hydrogen electrode (SHE); at these potentials, no dissolution of Fe was detected. Potential transients obtained during cathodic reactivation and the XPS results suggest that an air-formed oxide of Fe3O4 is responsible for this behavior. The anodic polarization behavior of sintered Fe was similar to that of bulk Fe, showing active, passive, and oxygen evolution regions. A very high current density observed in the passive region for some sintered specimens was attributable to active dissolution within the pore structure, analogous to conditions during crevice corrosion. The presence of oxygen in the solution stabilized both the passive film and the more noble apparent OCP.

Kim, H. S.; Kho, Y. T.; Osseo-Asare, K.; Pickering, H. W.

1991-06-01

144

A circulatory system and method of slurry delivery in long-distance pipeline transportation of iron ore  

NASA Astrophysics Data System (ADS)

Long-distance pipeline transportation of iron ore is a very good method to solve the iron ore delivering outside, and also suitable for the western complicated terrain and convenient traffic. Before the pipeline transporting the slurry, you need a low concentration of slurry (slurry concentration of less than 68%) that is concentrated and then transport to the mixing tank to mix uniformly. There will be a small amount of selected birth to mine in the upper reaches of the production process, which resulting concentration of slurry concentrated pool is low, and thus it can not meet the requirements that we have set concentration of slurry concentration, so the slurry can not be sent to the mixing tank, and the production is affected ultimately. Therefore, this paper presents a method of circulatory system and slurry delivery to solve such problems. It has been proved in practice that the system effectively improve the production and generalization efficiently.

Li, Youling; Wang, Hua

2011-10-01

145

Environmental aspects in Dalli-Rajhara iron ore mine area, M.P. using digital image processing techniques  

Microsoft Academic Search

Landsat MSS (1982) and IRS LISS-II (1989) data have been used to study the land use\\/land cover changes in Dalli-Rajhara iron\\u000a ore mine area. Supervised classification has been performed on the temporal data to generate land use\\/land cover maps. Land\\u000a use\\/land cover categories generated from IRS LISS-II data of 36 m resolution has been resampled to 80 m and areal

A Jeyaram; R Balasubramanian; Y Vxxx N Krishna Murthy; R L Karale; Balbhir Singh

1993-01-01

146

Changes in iron content in sphalerites in relation to structural conditions and localization of ores in Kholst deposit  

Microsoft Academic Search

A consistent, relatively rapid decrease in FeS molecular content of sphalerites at decreasing depth is recognizable in upper parts of this structurally controlled Pb-Zn ore deposit, as an expression of tectonic calm and continuity of the productive stages of the mineralization. Elsewhere, in the depths, abrupt changes in quantity of isomorphous iron in sphalerites, within a relatively short depth-span, signify

Ye M. Nekrasav

1971-01-01

147

THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY  

SciTech Connect

This report represents the thirteenth Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this semi annual reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township's Jacobs Road Compost Storage Facility, construction was completed during this reporting period and surface monitoring began. Surface monitoring was conducted periodically at the Mt. Hope Road subsidence work area and adjacent areas after the January 2000 construction effort.

Gary Gartenberg

2003-12-01

148

THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TONWSHIP, NEW JERSEY  

SciTech Connect

This report represents the tenth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government-Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township Compost Storage Facility, engineering continued during this reporting period toward development of the Construction Plans and Technical Specifications for the remediation work. At the Mt. Hope Road subsidence, surface monitoring was conducted periodically at the work area and adjacent areas after the January 2000 construction effort.

Gary Gartenberg

2003-02-01

149

Densification and microstructure development in the reaction sintering process of yttrium iron garnet  

Microsoft Academic Search

Factors affecting the densification and microstructure development in the reaction sintering process (RSP) of yttrium iron garnet were investigated. Three different powder mixtures were used: Fe2O3\\/Y2O3, Fe2O3\\/YFeO3 (1100 C calcined), and Fe2O3\\/YFeO3 (1200 C calcined). The conventionally prepared garnet powder was also adopted as a reference material. It was found that the RSP using Fe2O3-YFeO3 systems has a

R. J. Young; T. B. Wu; I. N. Lin

1990-01-01

150

Effect of Iron Content on Sintering Behavior of Ti-V-Fe-Al Near- ? Titanium Alloy  

NASA Astrophysics Data System (ADS)

Two near- ? Ti-10V-3Fe-3Al and Ti-10V-2Fe-3Al alloys were produced by blended elemental powder metallurgy using hydrogenated titanium and V-Fe-Al master alloy powders. The distributions of the alloying elements were investigated at different stages of transformation of the heterogeneous powder compacts into the final homogeneous alloy product. The influence of iron content on chemical homogenization, densification, microstructure, and mechanical properties of as-sintered alloys was discussed with respect to the fast diffusion mobility of iron in titanium. It was concluded that a 1 pct increase in Fe content, as the alloying element with the fastest diffusivity in titanium, has a positive effect on densification. However, this also results in some grain coarsening of the final material. The attained mechanical properties were comparable with those of cast/wrought near-beta titanium alloys.

Savvakin, Dmytro G.; Carman, Andrew; Ivasishin, Orest M.; Matviychuk, Mykhailo V.; Gazder, Azdiar A.; Pereloma, Elena V.

2012-02-01

151

Tribological behaviour and statistical experimental design of sintered ironcopper based composites  

NASA Astrophysics Data System (ADS)

The sintered ironcopper based composites for automotive brake pads have a complex composite composition and should have good physical, mechanical and tribological characteristics. In this paper, we obtained frictional composites by Powder Metallurgy (P/M) technique and we have characterized them by microstructural and tribological point of view. The morphology of raw powders was determined by SEM and the surfaces of obtained sintered friction materials were analyzed by ESEM, EDS elemental and compo-images analyses. One lot of samples were tested on a "pin-on-disc" type wear machine under dry sliding conditions, at applied load between 3.5 and 11.5 10?1 MPa and 12.5 and 16.9 m/s relative speed in braking point at constant temperature. The other lot of samples were tested on an inertial test stand according to a methodology simulating the real conditions of dry friction, at a contact pressure of 2.53 MPa, at 3001200 rpm. The most important characteristics required for sintered friction materials are high and stable friction coefficient during breaking and also, for high durability in service, must have: low wear, high corrosion resistance, high thermal conductivity, mechanical resistance and thermal stability at elevated temperature. Because of the tribological characteristics importance (wear rate and friction coefficient) of sintered ironcopper based composites, we predicted the tribological behaviour through statistical analysis. For the first lot of samples, the response variables Yi (represented by the wear rate and friction coefficient) have been correlated with x1 and x2 (the code value of applied load and relative speed in braking points, respectively) using a linear factorial design approach. We obtained brake friction materials with improved wear resistance characteristics and high and stable friction coefficients. It has been shown, through experimental data and obtained linear regression equations, that the sintered composites wear rate increases with increasing applied load and relative speed, but in the same conditions, the frictional coefficients slowly decrease.

Popescu, Ileana Nicoleta; Ghi??, Constantin; Bratu, Vasile; Palacios Navarro, Guillermo

2013-11-01

152

Photosynthesis and oxidative stress in the restinga plant species Eugenia uniflora L. exposed to simulated acid rain and iron ore dust deposition: Potential use in environmental risk assessment  

Microsoft Academic Search

The Brazilian sandy coastal plain named restinga is frequently subjected to particulate and gaseous emissions from iron ore factories. These gases may come into contact with atmospheric moisture and produce acid rain. The effects of the acid rain on vegetation, combined with iron excess in the soil, can lead to the disappearance of sensitive species and decrease restinga biodiversity. The

Natlia Rust Neves; Marco Antonio Oliva; Danilo da Cruz Centeno; Alan Carlos Costa; Rogrio Ferreira Ribas; Eduardo Gusmo Pereira

2009-01-01

153

THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY  

SciTech Connect

This report represents the seventh Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the Green Pond Mine site at the Township Compost Storage Facility, research and preliminary design was performed during this reporting period toward development of the engineering plans and Technical Specifications for the remediation work. At the White Meadow Mine site, the remediation project was conducted last reporting period by others, out of the responsibility of Rockaway Township under this Cooperators Agreement. At the Mt. Hope Road subsidence, surface monitoring was conducted at the work area and adjacent areas after the January 2000 construction effort.

Gary Gartenberg, P.E., P.P.

2001-04-01

154

THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY  

SciTech Connect

This report represents the sixth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. At the White Meadow Mine site, after amended specifications were prepared and continued negotiations took place with the Property Owner, the property ownership was transferred during the reporting period. As a result in the change in property ownership, the remediation project was then to be done by the new Property Owner out of the responsibility of Rockaway Township under this Cooperators Agreement. At the Mt. Hope Road subsidence, surface monitoring was conducted at the work area and adjacent areas after the January 2000 construction effort. At the Green Pond Mine site at the Township Compost Storage Facility, no additional field work was undertaken during this reporting period subsequent to the previous completion of the geophysical survey. With the termination of the White Meadow Mine project, work began toward development of a remedial design for the Green Pond Mines.

Gary Gartenberg, P.E., P.P.

2001-04-01

155

THE REMEDIATION OF ABANDONED IRON ORE MINE SUBSIDENCE IN ROCKAWAY TOWNSHIP, NEW JERSEY  

SciTech Connect

This report represents the fourth Semi-Annual Technical Progress Report issued in connection with the subsidence remediation projects undertaken by Rockaway Township in Morris County, New Jersey. This report provides a summary of the major project work accomplished during this reporting period and contemplated for the subsequent reporting period. This report is issued as part of the project reporting provisions set forth in the Cooperators Agreement between the United States Government--Department of Energy, and Rockaway Township. The purpose of the Cooperators Agreement is for the Department of Energy to provide technical and financial assistance in a coordinated effort with Rockaway Township to develop and implement a multi-phased plan to remediate ground stability problems associated with abandoned mining activity. Primarily during the 1800's, extensive iron ore mining and prospecting was undertaken in Rockaway Township, part of the Dover District Mining region in Morris County. The abandoned mining activity has resulted in public safety hazards associated with ground collapse and surface subsidence features evolving in both developed and undeveloped areas within Rockaway Township. During this reporting period the Engineering Design for remediation of the surface safety hazards associated with the White Meadow Mine was completed. Construction Plans and Technical Specifications were completed and competitive bids were solicited by the Township for completion of the work. The electrical resistivity survey analysis and report was completed for the Green Pond Mines site at the Township Compost Storage Facility. The geophysical survey results confirmed evidence of abandoned mining activity at the Green Pond Mine site which was previously identified. During this reporting period, the time frame of the Cooperative Agreement between the Township and the Department of Energy was extended. An additional site of subsidence with in the Township related to abandoned mining activity at Mount Hope Road was selected by Rockaway Township to be considered for remediation and inclusion under the Cooperative Agreement.

Gary Gartenberg, P.E., P.P.

1999-10-01

156

Natural magnetite nanoparticles from an iron-ore deposit: size dependence on magnetic properties  

NASA Astrophysics Data System (ADS)

We report on the discovery of magnetite nanoparticles ranging in size from 2 to 14 nm in the mineralized zones of the Pea Colorada iron-ore deposit, southern Mexico. Micrometric scale magnetite was magnetically reduced and divided into distinct size ranges: 85-56 ?m, 56-30 ?m, 30-22 ?m, 22-15 ?m, 15-10 ?m, 10-7 ?m and 7-2 ?m. Nanometric-scale magnetite in the size range 2-14 nm was identified. The magnetite was characterized by X-ray diffraction, transmitted and reflected light microscope, high-resolution transmission electron microscopy (TEM), high angle annular dark field, Mssbauer spectroscopy and its magnetic properties. Crystallographic identification of nanostructures was performed using high-resolution TEM. Characteristic changes were observed when the particles make the size transition from micro- to nanometric sizes, as follows: (1) frequency-dependent magnetic susceptibility percentage (?FD%) measurements show high values (13%) for the 2-14 nm fractions attributed to dominant fractions of superparamagnetic particles; (2) variations of ?FD% < 4.5% in fractions of 56-0.2 ?m occur in association with the presence of microparticles formed by magnetite aggregates of nanoparticles (<15 nm) embedded in berthierine; (3) Mssbauer spectroscopy results identified a superparamagnetic fraction; (4) nanometric and 0.2-7 ?m grain size magnetite particles require a magnetic field up to 152 mT to reach saturation during the isothermal remanent magnetization experiment; (5) coercivity and remanent magnetization of the magnetite increase when the particle size decreases, probably due to parallel coupling effects; (6) two-magnetic susceptibility versus temperature experiments of the same 2-14 nm sample show that the reversibility during the second heating is due to the formation of new magnetite nanoparticles and growth of those already present during the first heating process.

Rivas-Snchez, M. L.; Alva-Valdivia, L. M.; Arenas-Alatorre, J.; Urrutia-Fucugauchi, J.; Perrin, M.; Goguitchaichvili, A.; Ruiz-Sandoval, M.; Ramos Molina, M. A.

2009-01-01

157

The correlation of technological parameters and the structure of cold sintered iron as a basis for material property prognosis  

Microsoft Academic Search

This study researches the influence of microstructure formation on the technological parameters of cold sintered iron powder. The emphasis is given to the study of the material characteristics structure in consideration of the crystal structure, grain size and evolution of the microstructure constituents. From the thermodynamic point of view, the problem of microstructure stability was studied in particular. The correlation

Milutin R. Djuricic; Zagorka S. Acimovic-Pavlovic; Ljubisa D. Andric

2006-01-01

158

Phytoremediation: A Novel Approach for Utilization of Iron-ore Wastes  

Microsoft Academic Search

\\u000a Large amounts of toxic contaminants are being released to the environment around the globe from rapid urbanization and industrialization.\\u000a Among such contaminants are industrial wastes and ore tailings that result from worldwide mining activities. In mining operations,\\u000a during the processing of low-grade ores, significant quantities of wastes or tailings are produced. The overburden material\\u000a (also known as waste), generated during

Monalisa Mohanty; Nabin Kumar Dhal; Parikshita Patra; Bisweswar Das; Palli Sita Rama Reddy

159

Direct Biohydrometallurgical Extraction of Iron from Ore. (Final Technical Report, October 10, 2003-September 30, 2005).  

National Technical Information Service (NTIS)

A completely novel approach to iron extraction was investigated, based on reductive leaching of iron by anaerobic bacteria. Microorganisms were collected from an anaerobic bog where natural seepage of dissolved iron was observed. This mixed culture was us...

T. C. Eisele

2005-01-01

160

A comparative study of the wear behaviour of sintered and laser surface melted AISI M42 high speed steel diluted with iron  

Microsoft Academic Search

Powders of AISI M42 high-speed steel (HSS) were blended with different proportions of water-atomised iron powders. The powders were subsequently submitted to uniaxial pressing and then divided in three lots. The first was submitted to sintering, the second was submitted to sintering plus laser surface melting (LSM) and the third was submitted to sintering plus LSM plus double tempering at

R. Colao; E. Gordo; E. M. Ruiz-Navas; M. Otasevic; R. Vilar

2006-01-01

161

Study the effect of chromite ore properties on pelletisation process  

Microsoft Academic Search

Chrome ore properties play a critical role in various pelletisation subprocesses (grinding, filtering, pelletisation and sintering) and slight variation in ore properties significantly affect the whole pelletisation process. Three ore samples (sample-A, B and C) were collected from different working faces of a chromite ore mine. Experiments were carried out to find out the difference in grinding (Inherent ore granulometry,

Veerendra Singh; S. Mohan Rao

2008-01-01

162

Blast schedule planning and shiftwise production scheduling of an opencast iron ore mine  

Microsoft Academic Search

In this paper we present a computer integrated system for short-range mine production planning that uses: (i) a linear programming model for the choice of blocks to be blasted; (ii) a stochastic programming model for the selection of the blasted areas to be excavated and in deciding the quantity of ores and wastes to be mined from each of the

Diatha Krishna Sundar; Damodar Acharya

1995-01-01

163

Processing of iron-titanium powder mixtures by transient liquid phase sintering  

Microsoft Academic Search

Transient liquid phase sintering was examined for Fe-Ti powder mixtures. The experimental plan included the effects of several processing variables, such as green density, particle size, composition, heating rate, sintering temperature, and sintering time. During heating, pores form at the Ti particle sites. At the first eutectic temperature (1085 C), liquid spreading is inhibited by a surrounding intermetallic envelope, leading

R. M. German; J. W. Dunlap

1986-01-01

164

Effect of rhizobia, mycorrhizal fungi and phosphate-solubilizing microorganisms in the rhizosphere of native plants used to recover an iron ore area in Brazil  

Microsoft Academic Search

The iron-ore deposits in Minas Gerais state are concentrated in an area named Ferruginosous Quadrilateral, in which the dominant vegetation belongs to the Cerrado biome (savanna type, called campo rupestre or rupestrian field). This vegetation occurs in altitudes higher than 1000m and is one of the most endangered biomes of the world. This study aimed to restore an area of

Sandra Rosa Matias; Marcela Cludia Pagano; Frederico Carvalho Muzzi; Christiane A. Oliveira; Andrea Almeida Carneiro; S Nadja Horta; Maria Rita Scotti

2009-01-01

165

Determination of groundwater and geological factors using geoelectrical methods to design a suitable drainage system in Gol-e-Gohar iron ore mine, Iran  

Microsoft Academic Search

Various problems caused by the presence of underground water in Gol-e- Gohar iron ore mine have made mining experts seek proper solutions. One of the best solutions is to make a suitable drainage system for leading the mine waters to an area outside of the mine limits. However, the ground- water situation and geological structures such as active faults present

Abolghasem Kamkar-Rouhani; Azadeh Hojat

166

From Grounded Skills to Sky Qualifications: A Study of Workers Creating and Recreating Qualifications, Identity and Gender at an Underground Iron Ore Mine in Sweden  

Microsoft Academic Search

Over a period of 50 years at Kiruna iron ore mine in the far north of Sweden we can see a transformation of work from underground to remote control at surface level. What characterized the old underground workface was the close relation between man and the hard rock centred on arduous physical work under dangerous conditions. Today, the face miners

Lena Abrahamsson; Jan Johansson

2006-01-01

167

Paleomagnetism, rock magnetism and opaque mineralogy of iron ore deposits from southern Mexico and their implications for quantitative modelling of magnetometric data  

Microsoft Academic Search

Paleomagnetism, Rock Magnetism and Opaque Mineralogy of Iron Ore Deposits from Southern Mexico and Their Implications for Quantitative Modelling of Magnetometric Data. The tectonic history of the Pacific continental margin is critical for understanding their mineral deposits. The margin presents intrusive and volcanic activity characteristic of magmatic arcs of subduction zones, which are genetically related with deposits of Cu, Fe,

L. M. Alva-Valdivia; Fucugauchi; J. Urrutia; H. Bohnel; D. J. Moran Zenteno

1990-01-01

168

Smelting of Iron Ore in FeCrCSi Melts  

Microsoft Academic Search

Direct smelting of the South African Sishen hematite ore in FeCrCSi melts was studied, where the aim was to increase the Fe\\/Cr ratio of high carbon ferrochrome melts in order to approach stainless steel compositions. Experiments in the temperature range of 1600C to 1750C were conducted in an inductively heated rotating cylinder technique furnace; however, due to the very fast

E. Vardar; R. Hurman Eric

2008-01-01

169

Energy requirements in Minnesota iron ore and taconite mining 1953 - 2000  

Microsoft Academic Search

This report is concerned primarily with forecasting energy requirements for taconite and iron mining in Minnesota until 2,000, and additionally with the role in the industry in the economy of both the State and the three-county Iron Range region of northeastern Minnesota. Direct energy inputs in iron mining in 1973 are related to three end-use categories: production, transportation, and overhead

H. Hirsch

1975-01-01

170

Processing of iron-titanium powder mixtures by transient liquid phase sintering  

Microsoft Academic Search

Transient liquid phase sintering was examined for Fe-Ti powder mixtures. The experimental plan included the effects of several\\u000a processing variables, such as green density, particle size, composition, heating rate, sintering temperature, and sintering\\u000a time. During heating, pores form at the Ti particle sites. At the first eutectic temperature (1085 C), liquid spreading is\\u000a inhibited by a surrounding intermetallic envelope, leading

R. M. German; J. W. Dunlap

1986-01-01

171

Reduction of iron ore fines by coal fines in a packed bed and fluidized bed apparatusA comparative study  

NASA Astrophysics Data System (ADS)

Reduction of iron ore fines by coal fines in packed and fluidized beds has been studied. The investigation includes study of the kinetic aspects of reduction, carbon and sulfur content of the direct reduced iron (DRI) produced, and metallography of the products. For both processes, the kinetic data fit the first-order reaction model. Reduction in a fluidized bed is much faster than in a packed bed system. In both cases, DRI contains a substantial amount of free carbon at the initial stages of reduction. At the later stages of reduction, the carbon present in the DRI is mainly in the combined state. For identical temperatures and particle sizes, reaction in fluidized bed is much faster compared to that in a packed bed. At any particular degree of reduction, sulfur content in DRI samples produced by fluidized bed reduction is always more than that of DRI samples produced by packed bed reduction. Scanning electron microscopy (SEM) micrographs reveal that metallic whiskers formed during reduction in packed beds only. These whiskers become more prominent at higher temperatures and longer times.

Haque, R.; Ray, H. S.; Mukherjee, A.

1993-06-01

172

Are metal mining effluent regulations adequate: identification of a novel bleached fish syndrome in association with iron-ore mining effluents in Labrador, Newfoundland.  

PubMed

Water quality guidelines for industrial effluents are in place in many countries but they have generally evolved within a limited ecotoxicological framework. Effluents from iron-ore mines have traditionally been viewed by regulatory bodies as posing little or no risk to the aquatic environment. However, it was recently reported that lake trout taken from a large iron-ore contaminated Lake in Labrador (Wabush Lake) had elevated levels of DNA oxidative damage and were markedly depleted in levels of vitamin A (Payne et al., 1998) in comparison with fish from a Lake (Shabogamo Lake) receiving lesser levels of effluents. Through further observations, it has now been established that the lake trout in Wabush Lake are commonly affected with a marked skin bleaching syndrome in comparison with fish in Shabogamo Lake and a nearby Lake (Ashuanipi) which does not receive effluents. To the authors' knowledge such a syndrome which is characterized by marked reduction in skin pigmentation and overall increase in skin whitening has not been reported before in any fish population in association with contamination. Preliminary information for liver histopathological and blood cell differences have also been obtained in fish in Wabush Lake in comparison with Ashuanipi Lake. It has also been observed through studies on phosphatidyl liposomes that iron-ore leachate contains redox-active material (iron but possibly other transition metals) that has considerable potential for causing oxidative damage to cellular constituents. Using the weight of evidence approach it is indicated that iron-ore effluents may pose more of a risk to the aquatic environment than traditionally considered by regulatory agencies. PMID:11239690

Payne, J F; French, B; Hamoutene, D; Yeats, P; Rahimtula, A; Scruton, D; Andrews, C

2001-05-01

173

Synthesis and mechanical\\/magnetic properties of nano-grained iron-oxides prepared with an inert gas condensation and pulse electric current sintering process  

Microsoft Academic Search

Nanocrystalline iron-oxide powder was fabricated with an inert gas condensation (IGC) method combined with evaporation, and\\u000a in-situ oxidation techniques. The particle size of iron-oxide powder was controlled by varying the helium gas pressure between\\u000a 0.1 and 10 Torr, with the smallest one =10 nm at 0.1 Torr. The nanostructure was characterized by TEM. Nanocrystalline iron-oxide\\u000a powder was sintered with the

Yong-Ho Choa; Tatachika Nakayama; Tohru Sekino; Koichi Niihara

1999-01-01

174

OXYGEN AND HYDROGEN ISOTOPE GEOCHEMISTRY OF THE IRON ORE GROUP (IOG), INDIA: THE STABLE ISOTOPIC COMPOSITION OF THE ARCHEAN OCEAN  

NASA Astrophysics Data System (ADS)

The Iron Ore Group (IOG) of the Singbhum-Orissa craton in eastern India is an Archean greenstone belt that crops out within a NNE plunging asymmetric synclinorium, sandwiched between the Singbhum Granite Complex to the east and the Bonai Granite to the west. The IOG sequence consists of submarine rocks with lower basaltic-andesite at the base of the section followed successively upwards by lower shale, tuffs, banded iron ore, upper shale and upper lava. The metamorphic conditions for the lower lava of the western limb are higher (lower amphibolites facies) than the lower lava of the eastern limb and the upper lava, where conditions range from zeolite to greenschist facies. Oxygen isotope analysis of 23 metaigneous rocks exhibit a range of 0 ? ?18O ? 10 , (mean 6.8). The lower lava (3.7 ? ?18O ? 6.4; 7 lavas) and a single gabbro (-0.2) of the western limb are depleted relative to the mean of +6.8 whereas the lower (6.7 ? ?18O ? 8.3; 8 samples) and upper lavas (6.9 ? ?18O ? 10.1; 7 samples) of the eastern limb are both enriched in 18O compared to the mean of 6.8 and the average mantle ?18 value (5.7). The depletion in 18O of the western limb may be due to regional thermal metamorphism from the Bonai granite, and may not represent a complementary 18O-depleted oceanic crust as seen in the Phanerozoic. The ?18O of amphibole (1.6 ? ?18O ? 7.3) and feldspar (3.8 ? ?18O ? 11.8) show a wide range of values with both enrichments and depletions relative to primary igneous ?18O values. Hydrogen isotopes of 22 samples (-80 ? ?D ? -59, except for two values of -94.3 and -114.6) lie within the Phanerozoic ?D ranges of similar rocks. Hydrogen and oxygen isotopic data indicate that the alteration of the IOG greenstones was due to interaction with 18O-shifted Archean ocean water (0-10) whose most depleted calculated oxygen isotope ratio is similar to modern seawater (~0). This study compliments the results of other Archean greenstone belts, such as, the Barberton greenstone belt of western South Africa, the Pilbara block of western Australia, the Abitibi belt of Canada and the Isua greenstone belt of Greenland.

Banerjee, S.; Richards, I.; Ferguson, K.; Basu, A. R.; Gregory, R. T.

2009-12-01

175

[Clinical and morphologic characteristics of lung cancer in miners of Krivoy Rog iron-ore region and of uranium mines of Zhovti Vody].  

PubMed

Clinical and morphological features of cancer were observed in two groups of miners (of Krivoy Rog iron-ore and Zholty Vody uranium mines), working in hazardous labour conditions. In both of groups the disease course had typical features for lung cancer. Roentgenologic changes were observed, central cancer of left and right lung was revealed by bronchoscopy method. In all the cases lung cancer was morphologically proved and classified as squamous. Rapid progression of the disease and late medical aid appealability cause the patients consulted with their doctors only at the stage of II-III, sometimes III of the disease and it makes a distinction of lung cancer in miners of iron-ore and uranium mines. In order to prevent such a late diagnostics all the miners should be referred to the group of risk on lung cancer. PMID:17051723

Bednaryk, O M; Filipchenko, L L; Pan'kova, A O; Kryvoshe?, L O; Slinchenko, M Z

176

Meeting the challenge of the 80's cost reduction measures at the Iron Ore Company of Canada's Carol Project 1980-85  

SciTech Connect

The mining facilities, crushing plant, and concentrator of the Iron Ore Company of Canada were in operation by 1962. Today, the Carol Project has the capacity to produce 20 million tonnes of concentrate from which 10.5 million tonnes of pellets can be produced. The period 1980-85 spans a period of energy crisis, world-wide recession, and a consequent re-structuring of the North American steel industry as it struggles to survive in an arena of excess world stell making capacity, government subsidized industries, and the increasing competition from overseas and from developing countries. This paper reviews cost reduction programs implemented by the Iron Ore Company of Canada at its 'Carol Project' and emphasizes improvements made in labour productivity, energy conservation, mining strategy, quality control, and reduced cost through technical innovations over this difficult period. The cost reduction program is reviewed under the headings of labor productivity, energy conservation, mining strategy, technical innovations and quality control.

Tinto, I.A.

1985-01-01

177

Paleomagnetism, rock magnetism and opaque mineralogy of iron ore deposits from southern Mexico and their implications for quantitative modelling of magnetometric data  

SciTech Connect

Paleomagnetism, Rock Magnetism and Opaque Mineralogy of Iron Ore Deposits from Southern Mexico and Their Implications for Quantitative Modelling of Magnetometric Data. The tectonic history of the Pacific continental margin is critical for understanding their mineral deposits. The margin presents intrusive and volcanic activity characteristic of magmatic arcs of subduction zones, which are genetically related with deposits of Cu, Fe, Mo, Au, and Ag. Although the tectonic history has been complex, involving oblique plate subduction, lateral movements, accretion of magmatic arcs and oceanic plateaux, and lateral displacements of major blocks, the mineral deposits are spatially distributed along elongated belts that roughly follow the margin. The authors have conducted paleomagnetic, rock magnetic, and petrological studies of the iron ore deposits to investigate genesis, magnetic mineralogy, stratigraphic relationships, metamorphism, and applications on quantitative modelling of magnetometric data. The remanent magnetization and susceptibility data are necessary for interpretation of magnetic anomalies. The results permit a comparison of the mineral deposits along the continental margin.

Alva-Valdivia, L.M.; Fucugauchi, Urrutia, J.; Bohnel, H.; Moran Zenteno, D.J. (Universidad Nacional Autonoma de Mexico, Mexico City (Mexico))

1990-06-01

178

Monitoring Sintering Burn-Through Point Using Infrared Thermography  

PubMed Central

Sintering is a complex industrial process that applies heat to fine particles of iron ore and other materials to produce sinter, a solidified porous material used in blast furnaces. The sintering process needs to be carefully adjusted, so that the combustion zone reaches the bottom of the material just before the discharge end. This is known as the burn-through point. Many different parameters need to be finely tuned, including the speed and the quantities of the materials mixed. However, in order to achieve good results, sintering control requires precise feedback to adjust these parameters. This work presents a sensor to monitor the sintering burn-through point based on infrared thermography. The proposed procedure is based on the acquisition of infrared images at the end of the sintering process. At this position, infrared images contain the cross-section temperatures of the mixture. The objective of this work is to process this information to extract relevant features about the sintering process. The proposed procedure is based on four steps: key frame detection, region of interest detection, segmentation and feature extraction. The results indicate that the proposed procedure is very robust and reliable, providing features that can be used effectively to control the sintering process.

Usamentiaga, Ruben; Molleda, Julio; Garcia, Daniel F.; Bulnes, Francisco G.

2013-01-01

179

Rock-magnetic and oxide microscopy studies of the El Laco iron-ore deposits, Chilean High Andes: implications for magnetometric modeling  

NASA Astrophysics Data System (ADS)

Microscopy and rock-magnetic studies of the iron oxide-ore and host rocks in the El Laco deposits were carried out to characterize the magnetic mineralogy and the processes that affected the natural remanent magnetization (NRM) during emplacement and evolution of the iron-ore deposits. Particular attention was paid to identify the magnetic mineralogical composition (magnetite and/or titanomagnetite, and hematite and/or titanohematite, and titanomaghemite) and grain size. These data help to investigate the magnetic domain states and the remanence acquisition processes, and to assess their significance as a source of magnetic anomalies. Magnetite or Ti-poor magnetite, maghemite and hematite are commonly found in the ores and host rocks, respectively. The scatter in the natural remanent magnetization and cleaned remanence directions of the ores may result from physical movement of the ores during faulting or mining, or from perturbation of the ambient geomagnetic field during remanence acquisition within these strongly magnetic ores. The microscopy study under reflected light shows that magnetic carriers are mainly magnetite, with significant amounts of ilmenite-hematite minerals. Magmatic titanomagnetite, found in igneous rocks, shows trellis texture, which is compatible with high temperature (deuteric) oxy-exsolution processes. Supergene reactions in ore deposits at the eruptions conditions (still hot ore magma) is indicated by goethite and hematite oxide minerals. Grain sizes range from a few microns to >100 m, and dominant magnetic state PSD, in agreement with hysteresis measurements. Thermal spectra, continuous susceptibility measurements, and isothermal remanent magnetization (IRM) acquisition suggest a predominance of some spinels (titanomagnetite or titanomaghemite) with low-Ti content as magnetic carriers. Although the presence of (titano)hematites is evidenced by hysteresis and IRM studies, their contribution on total remanence seem to be minor. For the modeling process of the magnetic anomaly, we used data on bulk susceptibility and intensity and direction of the NRM in order to know the relative contributions of induced and remanent magnetization components and allow a greater control of the source bodies. The position and geometry of the main magnetic source are shown as an ENE-25 striking tabular body, steeply inclined (65) to the north.

Alva-Valdivia, L.; Gogichaishvili, A.; Rivas, M. L.; Morales, J.; Gonzalez, J.; Urrutia-Fucugauchi, J.

2003-04-01

180

Four-point bending fatigue behaviour of an iron-based laser sintered material  

Microsoft Academic Search

New material processing methods such as laser sintering of metal powder necessitates new knowledge and characterization of the material to support its implementation in technical applications. Fatigue behaviour of a laser sintered FeNiCu-alloy was studied with emphasis on crack path, initiation and propagation. Fatigue crack growth was investigated by surface replication in four-point bending fatigue tests. The fatigue behaviour was

Y. Wang; J. Bergstrm; C. Burman

2006-01-01

181

Exposure assessment to dust and free silica for workers of Sangan iron ore mine in Khaf, Iran.  

PubMed

We aimed to conduct an exposure assessment to dust and free silica for workers of Sangan iron ore mine in Khaf, Iran. The maximum concentrations of total dust and free silica were measured in crusher machine station at 801155 and 267mg/m(3), respectively. Meanwhile, the minimum concentrations were measured in official and safeguarding station at 8.32 and 0.0120.002mg/m(3), respectively. Also, the maximum concentrations of respirable dust and free silica were measured in Tappeh Ghermez drilling no. 1 at 6613 and 1.50.4mg/m(3), respectively, while the minimum concentrations were measured in pneumatic hammer at 5.263 and 0.010.005mg/m(3), respectively. Considerate to Iranian standard for respirable dust concentrations (0.11mg/m(3)) and international standards (ACGIH=0.1 and NIOSH=0.05mg/m(3)), it was found that dust and free silica amounts were much higher than national and international standard levels in this mine. PMID:21805121

Naghizadeh, Ali; Mahvi, Amir Hossein; Jabbari, Hossein; Derakhshani, Elham; Amini, Hassan

2011-07-30

182

Quantitative measurements of loss on ignition in iron ore using laser-induced breakdown spectroscopy and partial least squares regression analysis.  

PubMed

Laser-induced breakdown spectroscopy (LIBS) and partial least squares regression (PLSR) have been applied to perform quantitative measurements of a multiple-species parameter known as loss on ignition (LOI), in a combined set of run-of-mine (ROM) iron ore samples originating from five different iron ore deposits. Global calibration models based on 65 samples and their duplicates from all the deposits with LOI ranging from 0.5 to 10 wt% are shown to be successful for prediction of LOI content in pressed pellets as well as bulk ore samples. A global independent dataset comprising a further 60 samples was used to validate the model resulting in the best validation R(2) of 0.87 and root mean square error of prediction (RMSEP) of 1.1 wt% for bulk samples. A validation R(2) of 0.90 and an RMSEP of 1.0 wt% were demonstrated for pressed pellets. Data preprocessing is shown to improve the quality of the analysis. Spectra normalization options, automatic outlier removal and automatic continuum background correction, which were used to improve the performance of the PLSR method, are discussed in detail. PMID:21144150

Yaroshchyk, Pavel; Death, David L; Spencer, Steven J

2010-12-01

183

Ore Minerals  

NSDL National Science Digital Library

This three part lab introduces sulfides and other ore minerals. Part one - Ore Minerals: Students fill in a table giving the metal, formula, and mineral group of several ore minerals. Part two - Box of Rocks: Students examine trays of ore minerals and record their physical properties, composition, habit, occurence, economic value, and use and answer questions about color, luster, density, transparency, and availability. Part three - Famous Digs: Students answer a series of questions related to famous ore deposits.

Perkins, Dexter

184

Macrosegregation and sedimentation in liquid phase sintering: Specific studies in the nickel-tungsten system and iron-copper system  

NASA Astrophysics Data System (ADS)

Based on experimental results, a macrosegregation model has been proposed to explain sedimentation occurring in liquid phase sintering (LPS). Macrosegregation has been observed both in the sintering process of nickel-tungsten (Ni-W) alloys and iron-copper (Fe-Cu) alloys. The experimental results indicate that whether the mushy zone is located at the top or at the bottom of the sample, macrosegregation can occur if a nonuniform structure is formed during LPS. The initial particle settling or floating gives rise to the liquid composition gradient. Elimination of the gradient requires substantial time and is accompanied by a retreat of the mushy zone. At the same time, the mass in the mushy zone is transported to the liquid zone. If the initial settling does not happen, macrosegregation will not appear. But a "true" sedimentation can be observed. These two types of sedimentation were compared and the rates were quasi-quantitatively estimated. A numerical simulation model has been developed to simulate the macrosegregation process. This calculation provided a further understanding of the sedimentation mechanisms.

Xu, Lei

185

The electroless nickel plating of porous sintered iron-base parts  

Microsoft Academic Search

1.The electroless nickel plating of sintered parts should not be performed in alkaline solutions. The best results were obtained by nickel plating in acid solutions (pH 55.2).2.For obtaining nickel deposits 2025 thick, capable of resisting 3% NaCl solution for 7 h or longer, nickel plating should be performed in two stages.3.In order to prevent the corrosion of the internal surface,

L. M. Apininskaya; I. D. Radomysel'skii

1965-01-01

186

Hepatic retinoid levels in seven fish species (teleosts) from a tropical coastal lagoon receiving effluents from iron-ore mining and processing.  

PubMed

The present study was undertaken to investigate the possible effects of Fe and trace element exposure on hepatic levels of retinoids in seven fish species. Concentrations of retinoids were measured in fish collected from a coastal lagoon in Brazil that receives effluents from an iron-ore mining and processing plant. Fish from nearby coastal lagoons were also included to assess possible differences related to chemical exposure. Results indicated considerable differences in hepatic retinoid composition among the various species investigated. The most striking differences were in retinol and derivative-specific profiles and in didehydro retinol and derivative-specific profiles. The Perciformes species Geophagus brasiliensis, Tilapia rendalli, Mugil liza, and Cichla ocellaris and the Characiforme Hoplias malabaricus were characterized as retinol and derivative-specific, while the Siluriformes species Hoplosternum littorale and Rhamdia quelen were didehydro retinol and derivative-specific fish species. A negative association was observed between Al, Pb, As, and Cd and hepatic didehydro retinoid levels. Fish with higher levels of hepatic Fe, Cu, and Zn showed unexpectedly significant positive correlations with increased hepatic retinol levels. This finding, associated with the positive relationships between retinol and retinyl palmitate with lipid peroxidation, may suggest that vitamin A is mobilized from other tissues to increase hepatic antioxidant levels for protection against oxidative damage. These data show significant but dissimilar associations between trace element exposure and hepatic retinoid levels in fish species exposed to iron-ore mining and processing effluents, without apparent major impacts on fish health and condition. PMID:22095865

Pereira, Adriana A; van Hattum, Bert; Brouwer, Abraham

2011-12-21

187

Friction and wear of a sintered iron-phosphorus-base frictional material  

Microsoft Academic Search

1.Under normal service conditions (Tv=350C) the operating performence of ZhF material is determined by dynamic equilibrium between the buildup and wear of intermediate working layers, which consist mainly of a mixture of copper and iron oxides (Cu2O and Fe3O4).2.Under such conditions the mechanism of operation of a rubbing pair involves the following parallel elementary processes: reaction between the surfaces, direct

E. L. Shvedkov; G. M. Derkacheva; I. I. Panaioti; O. I. Fushchich; Z. A. Yaremenko

1976-01-01

188

Determinacao de ferro total em minerio de ferro por fluorescencia de raios-x utilizando o efeito Compton: comparacao com outras tecnicas analiticas. (Determination of total iron in iron ore by x-ray fluorescence analysis using the Compton effect: comparison with others analytical techniques).  

National Technical Information Service (NTIS)

Total iron in iron ores is determines by X-ray fluorescence analysis method using the compton effect. The Bragg angle is determined for compton no-coherent scattering related to K alpha of Rhodium. This measurement procedure can be used for best fitting o...

M. V. Castilho R. C. Oliveira

1991-01-01

189

Hydrothermal alteration, fluid inclusions and stable isotope systematics of the Alvo 118 iron oxide-copper-gold deposit, Carajs Mineral Province (Brazil): Implications for ore genesis  

NASA Astrophysics Data System (ADS)

The Alvo 118 iron oxide-copper-gold (IOCG) deposit (170 Mt at 1.0 wt.% Cu, 0.3 g/t Au) lies in the southern sector of the Itacanas Shear Belt, Carajs Mineral Province, along a WNW-ESE-striking, 60-km-long shear zone, close to the contact of the ~2.76-Ga metavolcano-sedimentary Itacainas Supergroup and the basement (~3.0 Ga Xingu Complex). The Alvo 118 deposit is hosted by mafic and felsic metavolcanic rocks and crosscutting granitoid and gabbro intrusions that have been subjected to the following hydrothermal alteration sequence towards the ore zones: (1) poorly developed sodic alteration (albite and scapolite); (2) potassic alteration (biotite or K-feldspar) accompanied by magnetite formation and silicification; (3) widespread, pervasive chlorite alteration spatially associated with quartz-carbonate-sulphide infill ore breccia and vein stockworks; and (4) local post-ore quartz-sericite alteration. The ore assemblage is dominated by chalcopyrite (~60%), bornite (~10%), hematite (~20%), magnetite (10%) and subordinate chalcocite, native gold, Au-Ag tellurides, galena, cassiterite, F-rich apatite, xenotime, monazite, britholite-(Y) and a gadolinite-group mineral. Fluid inclusion studies in quartz point to a fluid regime composed of two distinct fluid types that may have probably coexisted within the timeframe of the Cu-Au mineralizing episode: a hot (>200C) saline (32.8 to 40.6 wt.% NaCl eq.) solution, represented by salt-bearing aqueous inclusions, and a lower temperature (<200C), low to intermediate salinity (<15 wt.% NaCl eq.) aqueous fluid defined by two-phase (LH2O + VH2O) fluid inclusions. This trend is very similar to those defined for other IOCG systems of the Carajs Mineral Province. ? 18OH2O values in equilibrium with calcite (-1.0 to 7.5 at 277C to 344C) overlap the lower range for primary magmatic waters, but the more 18O-depleted values also point to the involvement of externally derived fluids, possibly of meteoric origin. Furthermore, sulphide ? 34S values (5.1 to 6.3), together with available boron isotope and Cl/Br-Na/Cl data provide evidence for a significant component of residual evaporative fluids (e.g., bittern fluids generated by seawater evaporation) in this scenario that, together with magma-derived brines, would be the main sources of the highly saline fluids involved in the formation Alvo 118 IOCG deposit. The restricted high temperature sodic alteration, the pervasive overprinting of the potassic alteration minerals by chlorite proximal to the ore zones, ore breccias with open-space filling textures in brittle structures, microthermometric and stable isotope data indicate, collectively, that the Alvo 118 IOCG system developed at structurally high levels and may be considered the shallower representative of the IOCG systems of the CMP.

Torresi, Ignacio; Xavier, Roberto Perez; Bortholoto, Diego F. A.; Monteiro, Lena V. S.

2012-03-01

190

Assessment of Vegetation Establishment on Tailings Dam at an Iron Ore Mining Site of Suburban Beijing, China, 7 Years After Reclamation with Contrasting Site Treatment Methods  

NASA Astrophysics Data System (ADS)

Strip-mining operations greatly disturb soil, vegetation and landscape elements, causing many ecological and environmental problems. Establishment of vegetation is a critical step in achieving the goal of ecosystem restoration in mining areas. At the Shouyun Iron Ore Mine in suburban Beijing, China, we investigated selective vegetation and soil traits on a tailings dam 7 years after site treatments with three contrasting approaches: (1) soil covering (designated as SC), (2) application of a straw mat, known as "vegetation carpet", which contains prescribed plant seed mix and water retaining agent (designated as VC), on top of sand piles, and (3) combination of soil covering and application of vegetation carpet (designated as SC+VC). We found that after 7 years of reclamation, the SC+VC site had twice the number of plant species and greater biomass than the SC and VC sites, and that the VC site had a comparable plant abundance with the SC+VC site but much less biodiversity and plant coverage. The VC site did not differ with the SC site in the vegetation traits, albeit low soil fertility. It is suggested that application of vegetation carpet can be an alternative to introduction of topsoil for treatment of tailings dam with fine-structured substrate of ore sands. However, combination of topsoil treatment and application of vegetation carpet greatly increases vegetation coverage and plant biodiversity, and is therefore a much better approach for assisting vegetation establishment on the tailings dam of strip-mining operations. While application of vegetation carpet helps to stabilize the loose surface of fine-structured mine wastes and to introduce seed bank, introduction of fertile soil is necessary for supplying nutrients to plant growth in the efforts of ecosystem restoration of mining areas.

Yan, Demin; Zhao, Fangying; Sun, Osbert Jianxin

2013-09-01

191

Direct iron ore reduction by methane in a fluidized bed. Second annual report, November 1990-November 1991  

SciTech Connect

The partial oxidation and steam reforming of methane was studied in both fixed- and fluidized-bed reactors (both bench-scale). In the absence of iron particles, both pathways were found to produce a mixture of CO and H2 in a proportion consistent with equilibrium calculations at temperatures above 1050 C. When iron oxide particles were added, however, virtually no H2 was detected while the proportion of CO2 and CO depended strongly on the amount of water in the feed stream. Preliminary studies using reduced iron particles indicate that Fe/FeO is an active dissociation catalyst for methane. Finally, a fluidized reactor model has been shown to accurately describe both gas-phase and catalytic reactions in a fluidized bed. In this regard, new theory is presented which can explain the peculiar shape of the axial concentration profile in a fluidized bed as measured by in-bed sampling.

van der Vaart, D.R.; Conger, W.L.

1992-02-01

192

Ore and coal beneficiation method  

SciTech Connect

This patent describes a method for the separation of iron pyrite from a pulverized mineral ore comprising iron pyrites as a first constituent and a second constituent selected from the group consisting of coal and non-ferrous metal ores by air froth flotation of an aqueous pulp of the pulverized mineral ore. The improvement comprises incorporating in the pulp from about 0.02 to about 1 pound per ton of mineral of a composition comprising hydroxyacetic acid, xanthan gum, sodium silicate, and water wherein the acid content of the composition is from about 0.1 to about 69 percent by weight of the composition, the xanthan gum is from about 0.01 to about 10 percent by weight of the composition; and the ratio by weight of sodium silicate to hydroxyacetic acid is in the range of from about 0 to about 0.5.

Abadi, K.

1987-10-27

193

Respiratory symptoms and obstructive lung diseases in iron ore miners: report from the obstructive lung disease in northern Sweden studies.  

PubMed

This is a population-based study on the prevalence of respiratory symptoms assessed by a mail questionnaire. The objective was to examine if work in an iron mine increased the risk of airway symptoms or obstructive diseases. The exposed group consisted of 114 previous or current male miners. Referents, 2472 males from the province, had never been employed by the mining company or worked as miners. Age, smoking and a family history of asthma were considered as possible confounders. The miners had an increased risk for respiratory symptoms (OR=2.2, 95% CI=1.4-3.1) including recurrent wheeze (OR= 2.4, 95% CI= 1.5-3.9), longstanding cough (OR= 1.8, 95% CI = 1.0-3.2), and for physician-diagnosed chronic bronchitis (OR=2.2, 95% CI= 1.0-4.5). Attacks of shortness of breath and asthma manifestations were similar between miners and referents. Higher risks in miners were found particularly among the non-smokers for physician-diagnosed chronic bronchitis (OR=9.2, 95% CI= 3.0-28) and for symptoms as well. A family history of asthma was less common among miners (9.2% vs. 17%, p < 0.05). We conclude that miners in a modern underground iron mine had an increased risk of respiratory symptoms. In contrast to other studies, this increased risk was particularly found in nonsmokers. A family history of asthma may be an important confounder in occupational studies of respiratory diseases. PMID:15575354

Hedlund, Ulf; Jrvholm, Bengt; Lundbck, Bo

2004-01-01

194

Heat pipes with porous sintered wicks  

Microsoft Academic Search

In this study a vertical sintering oven is constructed and instrumented to enable a realization of sintering experiments of bronze inside capper tubes. The sintering oven consists of ceramic core around which is rolled helical electrical resistance of KW in power. The outside shell is made up of an iron tube and is thermically isolated. A thermocouple passes through the

K. A. R. Ismail; C. Y. Liu

1983-01-01

195

A new method for estimation of elastic properties of sintered iron powder compacts from ultrasonic longitudinal velocity  

Microsoft Academic Search

A new methodology has been proposed for estimation of elastic moduli of iron powder compacts solely based on longitudinal ultrasonic velocity. New correlations have been semianalytically derived between the elastic moduli and the longitudinal ultrasonic velocity. The moduli estimated on the basis of the suggested methodology agreed reasonably well with data reported for iron powder compacts in the literature. The

Kalyan K. Phani; Dipayan Sanyal

2008-01-01

196

SELECTIVE CHLORINATION OF TITANIUM ORE AND PRODUCTION OF TITANIUM POWDER BY PREFORM REDUCTION PROCESS (PRP)  

Microsoft Academic Search

A fundamental study was performed on the removal of iron from titanium ore by selective chlorination using metal chlorides (MClx, M = Mg, Ca, etc.) and the production of titanium powder directly from titanium ore. The objective of this study was to achieve reduction in the production cost of titanium. In order to remove iron from the ore, the titanium

H. Zheng; T. H. Okabe

197

Evolution of ore deposits on terrestrial planets  

NASA Astrophysics Data System (ADS)

Ore deposits on terrestrial planets materialized after core formation, mantle evolution, crustal development, interactions of surface rocks with the hydrosphere and atmosphere, and, where life exists on a planet, the involvement of biological activity. Core formation removed most of the siderophilic and chalcophilic elements, leaving mantles depleted in many of the strategic and noble metals relative to their chondritic abundances. Basaltic magma derived from partial melting of the mantle transported to the surface several metals contained in immiscible silicate and sulfide melts. Magmatic ore deposits were formed during cooling, fractional crystallization and density stratification from the basaltic melts. Such ore deposits found in earth's Archean rocks were probably generated during early histories of all terrestrial planets and may be the only types of igneous ores on Mars. Where plate tectonic activity was prevalent on a terrestrial planet, temporal evolution of ore deposits took place. Repetitive episodes of subduction modified the chemical compositions of the crust and upper mantles, leading to porphyry copper and molybdenum ores in calc-alkaline igneous rocks and granite-hosted tin and tungsten deposits. Such plate tectonic-induced mineralization in relatively young igneous rocks on earth may also have produced hydrothermal ore deposits on Venus in addition to the massive sulfide and cumulate chromite ores associated with Venusian mafic igneous rock. Sedimentary ore deposits resulting from mechanical and chemical weathering in reducing atmospheres in Archean earth included placer deposits (e.g., uraninite, gold, pyrite ores). Chromite, ilmenite, and other dense unreactive minerals could also be present on channel floors and in valley networks on Mars, while banded iron formations might underlie the Martian northern plains regions. As oxygen evolved in earth's atmosphere, so too did oxide ores. By analogy, gossans above sulfide ores probably occur on Mars, but not submarine ferromanganese nodules and crusts which have precipitated in oxygenated seawater on earth.

Burns, R. G.

198

Reduction of Iron-Oxide-Carbon Composites: Part I. Estimation of the Rate Constants  

NASA Astrophysics Data System (ADS)

A new ironmaking concept using iron-oxide-carbon composite pellets has been proposed, which involves the combination of a rotary hearth furnace (RHF) and an iron bath smelter. This part of the research focuses on studying the two primary chemical kinetic steps. Efforts have been made to experimentally measure the kinetics of the carbon gasification by CO2 and wstite reduction by CO by isolating them from the influence of heat- and mass-transport steps. A combined reaction model was used to interpret the experimental data and determine the rate constants. Results showed that the reduction is likely to be influenced by the chemical kinetics of both carbon oxidation and wstite reduction at the temperatures of interest. Devolatilized wood-charcoal was observed to be a far more reactive form of carbon in comparison to coal-char. Sintering of the iron-oxide at the high temperatures of interest was found to exert a considerable influence on the reactivity of wstite by virtue of altering the internal pore surface area available for the reaction. Sintering was found to be predominant for highly porous oxides and less of an influence on the denser ores. It was found using an indirect measurement technique that the rate constants for wstite reduction were higher for the porous iron-oxide than dense hematite ore at higher temperatures (>1423 K). Such an indirect mode of measurement was used to minimize the influence of sintering of the porous oxide at these temperatures.

Halder, S.; Fruehan, R. J.

2008-12-01

199

Geology of the Eymir iron mine, Edremit, Turkey  

USGS Publications Warehouse

The Eymir mine near Edremit on Turkey's Aegean coast (long 27?30'E.,1at 39?36'N.) was investigated as part of the Maden Tetkik ve Arama Enstitutsu (MTA)-U. S. Geological Survey (USGS) mineral exploration and training project, for the purpose of increasing the known mineral reserves. Geologic mapping of the mine area indicates that hematite is restricted to argillized, silicified, and pyritized dacite and possibly andesite. Hematite is present as massive replacements, impregnations, disseminations, and fracture fillings. Most of the upper part of the iron deposit consists of a breccia composed mostly of silicifiled dacite fragments in a hematite matrix. The iron deposit was apparently formed in three steps: 1. Argillation, silicification, and pyritization of the andesitic lava and dacite units as a result of a regional intrusion. 2. Intrusion of the Dere Oren dacite stock, with associated faulting, fracturing, and breccia formation at the surface. 3. Deposition of hematite by oxidation of pyrite, and transfer of iron via fractures and faults by hydrothermal or meteoric fluids. The Eymir iron deposit is a blanketlike deposit on the crest of the Sivritepe-Eymir ridge. It is 1300 meters long, 80 to 450 meters wide, and has an average thickness of 18.6 meters. Drill holes in the deposit show the iron content to range from 32.0 to 57.6 percent, and to average 46.5 percent. Most of the gangue is silica, and an arsenic impurity averaging 0.39 percent is present. Most of the deposit cannot be utilized as iron ore because of low iron content, high silica content, and high arsenic content. Ore-dressing tests have shown that it is feasible to concentrate the low-grade material, producing a concentrate having increased iron content and reduced silica content. Tests have shown also that the arsenic content of the ore can be reduced substantially by sintering. Further tests and economic feasibility studies are necessary to determine whether an economic marketable iron ore can be produced. If such studies indicate the technical and economic feasibility of utilizing all the Eymir iron deposit, detailed additional studies are recommended including: 1. A detailed drilling and sampling program to include 60 drill holes averaging 40 meters in depth and detailed sampling of mine dumps. 2. Pilot-plant testing of concentration and sintering procedures. 3. A detailed pre-investment economic feasibility study.

Jacobson, Herbert Samuel; Turet, Erdogan

1972-01-01

200

Hydrogen peroxide in sulfuric acid extraction of uranium ores  

Microsoft Academic Search

Uranium can be extracted from its ores at a pH of 2.5 to 5.5 using sulfuric acid, hydrogen peroxide, trace of iron and a sulfate. The extraction process is applicable to both tank leaching of conventionally mined ores and in situ leaching.

DeVries

1984-01-01

201

Hydrogen peroxide in sulfuric acid extraction of uranium ores  

SciTech Connect

Uranium can be extracted from its ores at a pH of 2.5 to 5.5 using sulfuric acid, hydrogen peroxide, trace of iron and a sulfate. The extraction process is applicable to both tank leaching of conventionally mined ores and in situ leaching.

DeVries, F.W.

1984-01-10

202

SINTERING METHOD  

DOEpatents

Methods of making articles by powder metallurgy techniques are presented. An article is made by packing a metal powder into a desired shape, raising the temperature of the powder compact to a sintering temperature in the presence of a reducing gas, and alternately increasing and decreasing the pressure of the gas while the temperatume is being raised. The product has a greater density than can be achieved by sintering for the same length of time at a constant gas pressure. (AEC)

Googin, J.M.

1963-11-01

203

Scientific Principles, Technology, and Equipment for Hydrometallurgical Processing of Uranium and Complex Ores  

Microsoft Academic Search

The development, over the last 50 years, of a technology for leaching various types of monouranium and complex ores, processed at hydrometallurgical plants, is examined. Leaching processes and the equipment required for them (including autoclave processes) for silicate, aluminosilicate, iron-bearing, carbonate uranium ores and complex uranium-phosphorus-bearing, uranium-vanadium, and uranium-molybdenum ores are described.

I. P. Smirnov; A. A. Matveev

2001-01-01

204

IRON  

Technology Transfer Automated Retrieval System (TEKTRAN)

Iron is an essential mineral. Although abundant in nature, it is mostly insoluble and biological absorbable forms are limited to most organisms. Iron is of fundamental importance to a variety of iron-containing proteins, especially the oxygen-carrying molecules hemoglobin and myoglobin. Iron may als...

205

Compaction and sintering characteristics of composite metal powders  

Microsoft Academic Search

The compaction and sintering characteristics of composite metal powders are examined using aluminium-copper, aluminium-iron and copper-iron powders. The density of a composite green compact is predicted based on the compacting pressure-density curve of each powder. The effects of the volume fraction of the mixed powders and the sintering temperature on the density and hardness of a sintered part are also

K. Yamaguchi; N. Takakura; S. Imatani

1997-01-01

206

Comparison of first order analysis and Monte Carlo methods in evaluating groundwater model uncertainty: a case study from an iron ore mine in the Pilbara Region of Western Australia  

NASA Astrophysics Data System (ADS)

The expansion of mining in the Pilbara region of Western Australia is resulting in the need to develop better water strategies to make below water table resources accessible, manage surplus water and deal with water demands for processing ore and construction. In all these instances, understanding the local and regional hydrogeology is fundamental to allow sustainable mining; minimising the impacts to the environment. An understanding of the uncertainties of the hydrogeology is necessary to quantify the risks and make objective decisions rather than relying on subjective judgements. The aim of this paper is to review some of the methods proposed by the published literature and find approaches that can be practically implemented in an attempt to estimate model uncertainties. In particular, this paper adopts two general probabilistic approaches that address the parametric uncertainty estimation and its propagation in predictive scenarios: the first order analysis and Monte Carlo simulations. A case example application of the two techniques is also presented for the dewatering strategy of a large below water table open cut iron ore mine in the Pilbara region of Western Australia. This study demonstrates the weakness of the deterministic approach, as the coefficients of variation of some model parameters were greater than 1.0; and suggests a review of the model calibration method and conceptualisation. The uncertainty propagation into predictive scenarios was calculated assuming the parameters with a coefficient of variation higher than 0.25 as deterministic, due to computational difficulties to achieve an accurate result with the Monte Carlo method. The conclusion of this case study was that the first order analysis appears to be a successful and simple tool when the coefficients of variation of calibrated parameters are less than 0.25.

Firmani, G.; Matta, J.

2012-04-01

207

Iron  

MedlinePLUS

... high in calories but low in vitamins and minerals. Sugar sweetened sodas and most desserts are examples ... higher doses of iron supplementation [ 86 ]. Iron and mineral interactions Some researchers have raised concerns about interactions ...

208

IRON  

EPA Science Inventory

The document surveys the effects of organic and inorganic iron that are relevant to humans and their environment. The biology and chemistry of iron are complex and only partially understood. Iron participates in oxidation reduction processes that not only affect its geochemical m...

209

A communication and monitoring system for an underground coal mine, iron ore mine, and deep underground silver mine. Open file report Jun 73-Mar 78  

SciTech Connect

Advanced communication and monitoring systems were developed and demonstrated in three underground mines representing different mining techniques, geographical areas, and material mined. The first was a large coal mine in western Pennsylvania using room-and-pillar techniques and continuous mining methods. The system developed provided private telephone channels, environmental monitoring, and control of underground equipment, all on a single coaxial cable, with all system operations under the direction of a minicomputer. The second was a magnetite ore mine in eastern Pennsylvania that used block caving mining techniques. A radio system was developed that provided two-way communications between trackless vehicles and roving personnel. A unique system of uhf-vhf repeaters combined with a 'leaky-feeder' transmission line offered operational and emergency features not previously found in mine communication systems. The third was a deep silver mine in the Cour d'Alene district of Idaho. This system utilizes a single wire pair to provide up to 14 voice channels. A combination of PBX, telephone carrier systems, and intercoms offered private conversations, selective signaling, and emergency backup communications.

Bergeron, A.A.; Collins, R.L.; Michels, J.L.

1981-11-01

210

Solubilization of Cu 2+ from copper ore by iron-oxidizing bacteria isolated from the natural environment and identification of the enzyme that determines Cu 2+ solubilization activity  

Microsoft Academic Search

Solubilization of Cu2+ from copper concentrate by 67 strains of iron-oxidizing bacteria isolated from the natural environment was studied. In the case of static growth on copper concentrate (5%)-salt medium (pH 2.5) at 30C, Cu2+ solubilization activities of 65 strains including Thiobacillus ferrooxidans strains AP19-3, OK-2, OK-3, OK150, Funis and NASF-1 ranged from 2.53.5 mg Cu2+\\/ml\\/33 d. In contrast, the

Tsuyoshi Sugio; Fauzia Akhter

1996-01-01

211

Two modelling approaches to water-quality simulation in a flooded iron-ore mine (Saizerais, Lorraine, France): a semi-distributed chemical reactor model and a physically based distributed reactive transport pipe network model.  

PubMed

The flooding of abandoned mines in the Lorraine Iron Basin (LIB) over the past 25 years has degraded the quality of the groundwater tapped for drinking water. High concentrations of dissolved sulphate have made the water unsuitable for human consumption. This problematic issue has led to the development of numerical tools to support water-resource management in mining contexts. Here we examine two modelling approaches using different numerical tools that we tested on the Saizerais flooded iron-ore mine (Lorraine, France). A first approach considers the Saizerais Mine as a network of two chemical reactors (NCR). The second approach is based on a physically distributed pipe network model (PNM) built with EPANET 2 software. This approach considers the mine as a network of pipes defined by their geometric and chemical parameters. Each reactor in the NCR model includes a detailed chemical model built to simulate quality evolution in the flooded mine water. However, in order to obtain a robust PNM, we simplified the detailed chemical model into a specific sulphate dissolution-precipitation model that is included as sulphate source/sink in both a NCR model and a pipe network model. Both the NCR model and the PNM, based on different numerical techniques, give good post-calibration agreement between the simulated and measured sulphate concentrations in the drinking-water well and overflow drift. The NCR model incorporating the detailed chemical model is useful when a detailed chemical behaviour at the overflow is needed. The PNM incorporating the simplified sulphate dissolution-precipitation model provides better information of the physics controlling the effect of flow and low flow zones, and the time of solid sulphate removal whereas the NCR model will underestimate clean-up time due to the complete mixing assumption. In conclusion, the detailed NCR model will give a first assessment of chemical processes at overflow, and in a second time, the PNM model will provide more detailed information on flow and chemical behaviour (dissolved sulphate concentrations, remaining mass of solid sulphate) in the network. Nevertheless, both modelling methods require hydrological and chemical parameters (recharge flow rate, outflows, volume of mine voids, mass of solids, kinetic constants of the dissolution-precipitation reactions), which are commonly not available for a mine and therefore call for calibration data. PMID:18037533

Hamm, V; Collon-Drouaillet, P; Fabriol, R

2007-10-24

212

Selection of grease lubricants for sintered sliding bearings  

Microsoft Academic Search

1.It has been shown that new complex synthetic greases have some advantages over the conventional materials for impregnating sintered sliding bearings.2.The heat- and moisture-resistant complex synthetic lubricants can be recommended for impregnating and lubricating sintered iron-graphite bearings.

V. D. Zozulya; Yu. L. Ishchuk

1967-01-01

213

Characterization of iron in airborne particulate matter  

NASA Astrophysics Data System (ADS)

In this work soil samples, iron ore and airborne atmospheric particulate matter (PM) in the Metropolitan Region of Belo Horizonte (MRBH), State of Minas Gerais, Brazil, are investigated with the aim of identifying if the sources of the particulate matter are of natural origin, such as, resuspension of particles from soil, or due to anthropogenic origins from mining and processing of iron ore. Samples were characterized by powder X-ray diffraction, X-ray fluorescence and 57Fe-Mssbauer spectroscopy. The results showed that soil samples studied are rich in quartz and have low contents of iron mainly iron oxide with low crystallinity. The samples of iron ore and PM have high concentration of iron, predominantly well crystallized hematite. 57Fe-Mssbauer spectroscopy confirmed the presence of similar iron oxides in samples of PM and in the samples of iron ore, indicating the anthropogenic origin in the material present in atmosphere of the study area.

Tavares, F. V. F.; Ardisson, J. D.; Rodrigues, P. C. H.; Brito, W.; Macedo, W. A. A.; Jacomino, V. M. F.

2013-02-01

214

38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...  

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

38. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE GEORGE M. CARL.' VIEW LOOKING EAST. (Also see OH-18-14, OH-18-39, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

215

14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE ...  

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

14. HULETT ORE UNLOADERS IN MOTION; UNLOADING CANADIAN RED ORE FROM THE 'GEORGE M. CAR.' VIEW LOOKING EAST. (Also see OH-18-38, OH-18-39, and OH-18-40.) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

216

Leaching Gold and Silver Ores.  

National Technical Information Service (NTIS)

Percolation leaching of gold or silver ores is accomplished by means of a process comprising initial pretreatment of the ore with a strong cyanide solution, followed by leaching with water to recover gold or silver values.

H. J. Heinen G. E. McClelland R. E. Lindstrom

1979-01-01

217

Upgrading of calcareous phosphate ores by flotation: Effect of ore characteristics  

Microsoft Academic Search

Sedimentary phosphates contain-besides the phosphate minerals-, various associated gangue minerals such as: clays, silica, calcareous minerals (mainly calcite and dolomite), carbonaceous matter, iron oxides and\\/or pyrite. The common practiced flow-sheets for concentrating these types of phosphate ores consist of a combination of various mineral processing units such as: crushing and screening, attrition, washing, magnetic separation, and\\/or flotation. However, none of

A.-Z. M. Abouzeid; A. T. Negm; D. A. Elgillani

2009-01-01

218

O-Ring Insertion Tool.  

National Technical Information Service (NTIS)

The instant invention relates to electrical connectors and more particularly to a tool for accurately and effectively installing an O-ring in an inwardly facing O-ring groove in an electrical connector without causing damage to the O-ring. While it has ge...

F. Zannini

1990-01-01

219

Bioprocessing of ores: Application to space resources  

NASA Astrophysics Data System (ADS)

The role of microorganisms in the oxidation and leaching of various ores (especially those of copper, iron, and uranium) is well known. This role is increasingly being applied by the mining, metallurgy, and sewage industries in the bioconcentration of metal ions from natural receiving waters and from waste waters. It is concluded that bioprocessing using bacteria in closed reactors may be a variable option for the recovery of metals from the lunar regolith. Obviously, considerable research must be done to define the process, specify the appropriate bacteria, determine the necessary conditions and limitations, and evaluate the overall feasibility.

Johansson, Karl R.

220

Next Generation Metallic Iron Nodule Technology in Electric Arc Steelmaking - Phase II  

Microsoft Academic Search

The current trend in the steel industry is a gradual decline in conventional steelmaking from taconite pellets in blast furnaces, and an increasing number of alternative processes using metallic scrap iron, pig iron and metallized iron ore products. Currently, iron ores from Minnesota and Michigan are pelletized and shipped to the lower Great Lakes ports as blast furnace feed. The

Donald R. Fosnacht; Iwao Iwasaki; Richard F. Kiesel; David J. Englund; David W. Hendrickson; Rodney L. Bleifuss

2010-01-01

221

Possible lunar ores  

NASA Astrophysics Data System (ADS)

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.

Gillett, Stephen L.

222

[Determination of gold in copper matte and sintered copper material].  

PubMed

Ore sample, pretreated at 650 degrees C, was decomposed with aqua regia. Gold in the sample solution was then pre-concentrated by adsorbing with polyurethane foam plastic, released with thiourea solution, and determined by inductively coupled plasma-atomic emission spectrometry and flame atomic absorption spectrometry. Based on the characteristic of the copper matte and sinter containing copper, the effects of sample dissolving condition, matrix effect and interference of coexisting elements were investigated. The accuracy, precision and detection limit were discussed. The results of test show that both of the two methods were suitable for determining the contents of gold in copper matte and sintered copper material. PMID:21800614

Ge, Yu-wei; Xiao, Li-mei; Suo, Jin-ling; Wang, Cheng; Hu, Xiao-min; Zhao, Shu-yun

2011-05-01

223

Biomineralization of metal-containing ores and concentrates.  

PubMed

Biomining is the use of microorganisms to extract metals from sulfide and/or iron-containing ores and mineral concentrates. The iron and sulfide is microbially oxidized to produce ferric iron and sulfuric acid, and these chemicals convert the insoluble sulfides of metals such as copper, nickel and zinc to soluble metal sulfates that can be readily recovered from solution. Although gold is inert to microbial action, microbes can be used to recover gold from certain types of minerals because as they oxidize the ore, they open its structure, thereby allowing gold-solubilizing chemicals such as cyanide to penetrate the mineral. Here, we review a strongly growing microbially-based metal extraction industry, which uses either rapid stirred-tank or slower irrigation technology to recover metals from an increasing range of minerals using a diversity of microbes that grow at a variety of temperatures. PMID:12480349

Rawlings, Douglas E; Dew, David; du Plessis, Chris

2003-01-01

224

Magnetic and flotation studies of banded hematite quartzite (BHQ) ore for the production of pellet grade concentrate  

NASA Astrophysics Data System (ADS)

To identify and establish beneficiation techniques for banded hematite quartzite (BHQ) iron ore, a comprehensive research on BHQ ore treatment was carried out. The BHQ ore was assayed as 38.9wt% Fe, 42.5wt% SiO2, and 1.0wt% Al2O3. In this ore, hematite and quartz are present as the major mineral phases where goethite, martite, and magnetite are present in small amounts. The liberation of hematite particles can be enhanced to about 82% by reducing the particle size to below 63 ?m. The rejection of silica particles can be obtained by magnetic and flotation separation techniques. Overall, the BHQ ore can be enriched to 65.3wt% Fe at 61.9% iron recovery. A flowsheet has been suggested for the commercial exploitation of the BHQ ore.

Das, B.; Mishra, B. K.; Prakash, S.; Das, S. K.; Reddy, P. S. R.; Angadi, S. I.

2010-12-01

225

Single-Step Ironmaking from Ore to Improve Energy Efficiency  

SciTech Connect

The pig iron nugget process was developed as an alternative to the traditional blast furnace process by Kobe Steel. The process aimed to produce pig iron nuggets, which have similar chemical and physical properties to blast furnace pig iron, in a single step. The pig iron nugget process utilizes coal instead of coke and self reducing and fluxing dried green balls instead of pellets and sinters. In this process the environmental emissions caused by coke and sinter production, and energy lost between pellet induration (heat hardening) and transportation to the blast furnace can be eliminated. The objectives of this research were to (1) produce pig iron nuggets in the laboratory, (2) characterize the pig iron nugget produced and compare them with blast furnace pig iron, (3) investigate the furnace temperature and residence time effects on the pig iron nugget production, and (4) optimize the operational furnace temperatures and residence times. The experiments involved heat treatment of self reducing and fluxing dried green balls at various furnace temperatures and residence times. Three chemically and physically different products were produced after the compete reduction of iron oxides to iron depending on the operational furnace temperatures and/or residence times. These products were direct reduced iron (DRI), transition direct reduced iron (TDRI), and pig iron nuggets. The increase in the carbon content of the system as a function of furnace temperature and/or residence time dictated the formation of these products. The direct reduced iron, transition direct reduced iron, and pig iron nuggets produced were analyzed for their chemical composition, degree of metallization, apparent density, microstructure and microhardness. In addition, the change in the carbon content of the system with the changing furnace temperature and/or residence time was detected by optical microscopy and Microhardness measurements. The sufficient carbon dissolution required for the production of pig iron nuggets was determined. It was determined that pig iron nuggets produced had a high apparent density (6.7-7.2 gr/cm3), highly metallized, slag free structure, high iron content (95-97%), high microhardness values (> 325 HVN) and microstructure similar to white cast iron. These properties made them a competitive alternative to blast furnace pig iron.

S.K. Kawatra; B. Anamerie; T.C. Eisele

2005-10-01

226

Reductive leaching of ilmenite ore in hydrochloric acid for preparation of synthetic rutile  

Microsoft Academic Search

The reactivity of ilmenite ore during leaching with hydrochloric acid can be greatly enhanced by reduction in solution using metallic iron. Addition of a particular amount of iron powder after a certain time of reaction will reduce all the dissolved Fe3+ to Fe2+ and reduce a portion of the dissolved Ti4+ to Ti3+. As the leaching continues, any further dissolved

M. H. H. Mahmoud; A. A. I. Afifi; I. A. Ibrahim

2004-01-01

227

Can I Trust ORE Reports?  

ERIC Educational Resources Information Center

|This issue of FEEDBACK, a newsletter produced by the the Austin Independent School District Office of Research and Evaluation (ORE), illustrates the accuracy, validity, and fairness of ORE reports. The independence of the reports is explained. Internal and external quality controls are used to ensure reliability and accuracy of the reports.

Feedback, 1984

1984-01-01

228

O-ring insertion tool  

Microsoft Academic Search

A tool for installing an O-ring in an inwardly facing O-ring groove in an electrical connection includes a guide shaft and a contact member slidably and rotatably received in the guide shaft. The guide shaft includes an elongated cylindrical shaft portion and a flared end portion on the shaft portion. The contact member includes an attachment portion for slidably and

Frank Zannini

1991-01-01

229

O-ring insertion tool  

NASA Astrophysics Data System (ADS)

A tool for installing an O-ring in an inwardly facing O-ring groove in an electrical connection includes a guide shaft and a contact member slidably and rotatably received in the guide shaft. The guide shaft includes an elongated cylindrical shaft portion and a flared end portion on the shaft portion. The contact member includes an attachment portion for slidably and rotatably securing the contact member on the shaft portion and a contact finger on the attachment portion which extends in a direction toward the flared end portion of the guide shaft. The tool is operable by assembling an O-ring on the shaft portion between the flared end portion and the contact finger, inserting the flared end portion into a connection and then manipulating the contact member to advance the O-ring into an O-ring groove in the connector with the contact finger.

Zannini, Frank

1991-09-01

230

Sintering Reaction of Pseudoleucite Syenite: Thermodynamic Analysis and Process Evaluation  

NASA Astrophysics Data System (ADS)

On the basis of comprehensive analysis of the modal composition of a pseudoleucite syenite ore sample, collected from the Zijin Hill of Lin County, Shanxi Province, thermodynamic analysis of the pseudoleucite syenite sintering process with sodium carbonate as the additive was carried out. It indicated that when the pseudoleucite syenite was sintered at 760-880C for 1.0-1.5 h, with sodium carbonate as the additive. The decomposition rate of minerals in the pseudoleucite syenite could reach 97.1%. The thermodynamic calculation shows that it needs to consume Na 2CO 3, i.e., 0.65 t treating per ton pseudoleucite syenite ore and approximately 95% of Na 2CO 3 could be recycled. This process consumes heat energy (2.29-2.48)10 -6 kJ, corresponding to standard coal 190.97-206.82 kg as the thermal efficiency was 40% and CO 2 emission was 0.77-0.81 t. Compared with the Russian limestone-sintering technique, the natural mineral resources and energy consumptions and greenhouse gas emissions of the soda-sintering technique were reduced by 65%, 63%, and 65%, respectively. It is, therefore, feasible that the procedure suggested in this article could be industrialized providing both economic benefit and environmental conservation.

TAN, Danjun; MA, Hongwen; LI, Ge; LIU, Hao; ZOU, Dan

231

Sintering Theory and Practice  

Microsoft Academic Search

Although sintering is an essential process in the manufacture of ceramics and certain metals, as well as several other industrial operations, until now, no single book has treated both the background theory and the practical application of this complex and often delicate procedure. In Sintering Theory and Practice, leading researcher and materials engineer Randall M. German presents a comprehensive treatment

Randall M. German

1996-01-01

232

Sinterability of titanium powder  

Microsoft Academic Search

The sintering process of compacts from dispersed titanium powders (as well as from metal powders with easily reducible oxides) is accomplished in two stages a nonsteady stage with a high densification rate and a steady stage, whose rate is determined by volume diffusion. The low values of energy of activation for densification in the first stage of sintering may

D. S. Arensburger

1970-01-01

233

SOME CHANGES IN DOMESTIC IRON MINING AS A RESULT OF PELLETIZATION  

Microsoft Academic Search

The purpose of this study is to assess the effects that pelletization has had on the iron ore production patterns in the United States between 1950 and 1965. To achieve this, the output of usable tons of iron ore, on a county basis, was mapped in order to describe and analyze the pattern of iron mining over the fifteen-year-period. It

PETER FRANK MASON

1969-01-01

234

Berthierine and chamosite hydrothermal: genetic guides in the Pea Colorada magnetite-bearing ore deposit, Mexico  

Microsoft Academic Search

We report the first finding of berthierine and chamosite in Mexico. They occur in the iron-ore deposit of Pea Colorada, Colima. Their genetic characteristics show two different mineralization events associated mainly to the magnetite ore. Berthierine is an Fe-rich and Mg-low 1:1 layer phyllosilicate of hydrothermal sedimentary origin. Its structure is 7 , dhkl [1 0 0] basal spacing and

M. L. Rivas-Sanchez; L. M. Alva-Valdivia; J. Arenas-Alatorre; J. Urrutia-Fucugauchi; M. Ruiz-Sandoval; M. A. Ramos-Molina

2006-01-01

235

Determination of beryllium in ores and rocks by a dilution-fluorometric method with morin  

USGS Publications Warehouse

Beryllium in concentrations as little as a few parts per million is determined fluorometrically with morin in low grade ores by a dilution method without separations. A high sensitivity is obtained by the adoption of instrumental and reaction conditions that give a satisfactory ratio of beryllium to blank fluorescence and at the same time minimize iron interference. Data on the behavior of 47 ions are given. The method is applied to ores containing bertrandite and beryl as the beryllium minerals.

May, R.; Grimaldi, F. S.

1961-01-01

236

Biooxidation of an arsenic-bearing refractory gold ore  

Microsoft Academic Search

Biological oxidation of a refractory arsenic-bearing gold ore was investigated to determine the fate of arsenic during processing and to assess the effect of biological pretreatment on gold extraction. Experiments were conducted using a consortium of iron and sulfide oxidizing bacteria in semi-batch and continuous-flow stirred bioreactors, and also in a tall column bioleaching system. Sulfide oxidation and arsenic solubilization

D Langhans; A Lord; D Lampshire; A Burbank; E Baglin

1995-01-01

237

Gaseous reduction of iron oxides: Part III. Reduction-oxidation of porous and dense iron oxides and iron  

Microsoft Academic Search

The internal reduction of high-grade granular hematite ore in hydrogen and carbon monoxide, and also the internal oxidation\\u000a of porous iron granules in CO2-CO mixtures have been investigated. To assist the interpretation of the rate data for porous iron and iron oxides, rate measurements\\u000a have been made also with dense wustite, previously grown on iron by oxidation. The iron formed

E. T. Turkdogan; J. V. Vinters

1972-01-01

238

Numerical investigation of sinter cooling process in sinter cooler  

NASA Astrophysics Data System (ADS)

In this paper, the sinter cooling process is numerically studied to get the pressure field, velocity field and temperature field when the fluid flows through the porous media by developing a two-dimensional unsteady state computational model. The inlet velocity, layer height, porosity and sinter layer distribution are the main parameters affecting the sinter cooling process. The computational fluid dynamics (CFD) technique is employed to investigate the influences of thermal process of the four parameters. When high temperature sinters are loaded into the sinter cooler from the sintering machine, phenomena of the non-uniform distribution of sinter size takes place which always causes the non-uniform distribution of sinter temperature field and leads to the deformation of the conveyors. In order to get a uniform sinter temperature field, several recommendations are proposed. The results discussed in this paper would be important for the further understanding of the thermal process and transformation of the sinter cooler.

Liu, Y.; Wang, J.; Yuan, X.; Yang, J.; Wang, Q. W.

2013-07-01

239

Sintering titanium powders  

SciTech Connect

Recently, there has been renewed interest in low-cost titanium. Near-net-shape powder metallurgy offers the potential of manufacturing titanium articles without costly and difficult forming and machining operations; hence, processing methods such as conventional press-and-sinter, powder forging and powder injection molding are of interest. The sintering behavior of a variety of commercial and experimental titanium powders was studied. Commercial powders were acquired that were produced different routes: (i) sponge fines from the primary titanium processing; (ii) via the hydride-dehydride process; and (iii) gas atomization. The influence of vacuum sintering time (0.5 to 32 hrs) and temperature (1200, 1275 or 1350C) on the microstructure (porosity present) of cold pressed powders was studied. The results are discussed in terms of the difference in powder characteristics, with the aim of identify the characteristics required for full density via press-and-sinter processing. Near-net-shape tensile bars were consolidated via cold pressed and sintered. After sintering, a sub-set of the tensile bars was hot-isostatic pressed (HIPed). The microstructure and properties of the bars were compared in the sintered and HIPed conditions.

Gerdemann, Stephen J.; Alman, David E.

2005-09-01

240

Management of solid wastes in the iron and steel industry  

SciTech Connect

Wastes from a local iron and steel factory operations are agglomeration of iron ore and sintering, pig iron manufacture, steel making, rolling mill operations, and pickling. Liquid slag, produced in the blast furnace, is granulated in water and used as a concrete additive. Other wastes are directed separately to sedimentation tanks. The settleable solids are reused, and the treated effluents are pumped to a cooling tower for recycling. As a result of the new manufacturing expansion, existing waste treatment facilities are not adequate, and it was found necessary to provide additional treatment techniques. Departmental, as well as composite wastes were treated using plain sedimentation, centrifugal sedimentation, or chemical coagulation, or a combination of these methods. The results obtained showed that the use of the hydrocyclone for solid-liquid separation is much more efficient than plain sedimentation. When this process was followed by coagulation, very promising results were obtained. The use of pickling liquor as a coagulant gave comparable results with alum and ferric chloride.

El-Gohary, F.; El-khouly, M.S.

1983-03-01

241

Sintered superhard materials.  

PubMed

Diamond or cubic boron nitride particles can be sintered into strong masses at high temperatures and very high pressures at which these crystalline forms are stable. Most of the desirable physical properties of the sintered masses, such as hardness and thermal conductivity, approach those of large single crystals; their resistance to wear and catastrophic splitting is superior. The sintered masses are produced on a commercial scale and are increasingly used as cutting tools on hard or abrasive materials, as wire-drawing dies, in rock drills, and in special high-pressure apparatus. PMID:17772811

Wentorf, R H; Devries, R C; Bundy, F P

1980-05-23

242

Sintered superhard materials  

SciTech Connect

Diamond of cubic boron nitride particles can be sintered into strong masses at high temperatures and very high pressures at which these crystalline forms are stable. Most of the desirable physical properties of the sintered masses, such as hardness and thermal conductivity, approach those of large single crystals; their resistance to wear and catastrophic splitting is superior. The sintered masses are produced on a commercial scale and are increasingly used as cutting tools on hard or abrasive materials, as wire-drawing dies, in rock drills, and in special high-pressure apparatus.

Wentorf, R.H.; DeVries, R.C.; Bundy, F.P.

1980-01-01

243

Mechanical properties of molybdenum alloyed liquid phase-sintered tungsten-based composites  

Microsoft Academic Search

Tungsten-based composites are fabricated from mixed elemental powders using liquid phase sintering, usually with a nickel-iron matrix. During sintering, the tungsten undergoes grain growth, leading to microstructure coarsening that lowers strength but increases ductility. Often the desire is to increase strength at the sacrifice of ductility, and historically, this has been performed by postsintering deformation. There has been considerable research

Preston B. Kemp; Randall M. German

1995-01-01

244

Experience of Improving Standards and Methods for Studying the Properties of Metal Powders and Sintered Articles  

Microsoft Academic Search

Reasons are considered for improving standards in the following methods for testing powder materials: tensile, transverse bending, gas and liquid permeability, and determination of powder compact dimensions after compaction pressure removal and during sintering. Calculated data for representative specimen dimensions (cross section and thickness) for these and other test methods for sintered articles (materials) prepared from mono- and polyfraction iron

Yurii G. Bezymyannyi

2003-01-01

245

Novel Binders and Methods for Agglomeration of Ore  

SciTech Connect

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 will 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%.

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

2006-12-31

246

Sintered composite filter  

Microsoft Academic Search

A particulate filter medium formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers is described. Preferred composition is about 40 vol.% quartz and about 60 vol.% stainless steel fibers. The media is sintered at about 1100°C to bond the stainless steel fibers into a cage network which holds the quartz fibers.

Bergman

1986-01-01

247

SEM, EDS and GDOES investigations for the identification of historical ferrous ore and slag from Sternmhlenthal valley in the outskirts of Chemnitz  

Microsoft Academic Search

SEM, EDS and GDOES investigations on ferrous ore and slag samples contribute to the local history of mining and metallurgy.\\u000a Quantitative X-ray analysis confirms the ore to be limonite. The slag consists of fayalithe and incompletely reduced ore parts\\u000a (iron scale). Additional calcium and charcoal inclusions were reactants of the bloomery process. The charcoal shows anatomical\\u000a details of spruce (Picea

D. Dietrich; P. Heger; E. Bucker; G. J. Nuys; T. Grafe; G. Urban

1998-01-01

248

The balance of TiTanium and vanadium in The blasT furnace wiTh The use of sinTer conTaining a TiTanium-vanadium-magneTiTe concenTraTe  

Microsoft Academic Search

The investigation concerned the use of sinter containing a titanium-vanadium-magnetite concentrate for the production of pig iron. Sinter containing 0,46 to 0,51 % TiO 2 and 0,056 to 0,060 % vanadium was used for pig iron production in the blast furnace. Introducing 200 kg of this concentrate to the1 Mg sinter mix did not cause any deterioration of sinter quality.

R. Budzik

2007-01-01

249

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

NASA Astrophysics Data System (ADS)

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.

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

2001-03-01

250

Sintering of calcium phosphate bioceramics.  

PubMed

Calcium phosphate ceramics have become of prime importance for biological applications in the field of bone tissue engineering. This paper reviews the sintering behaviour of these bioceramics. Conventional pressureless sintering of hydroxyapatite, Ca10(PO4)6(OH)2, a reference compound, has been extensively studied. Its physico-chemistry is detailed. It can be seen as a competition between two thermally activated phenomena that proceed by solid-state diffusion of matter: densification and grain growth. Usually, the objective is to promote the first and prevent the second. Literature data are analysed from sintering maps (i.e. grain growth vs. densification). Sintering trajectories of hydroxyapatite produced by conventional pressureless sintering and non-conventional techniques, including two-step sintering, liquid phase sintering, hot pressing, hot isostatic pressing, ultrahigh pressure, microwave and spark plasma sintering, are presented. Whatever the sintering technique may be, grain growth occurs mainly during the last step of sintering, when the relative bulk density reaches 95% of the maximum value. Though often considered very advantageous, most assisted sintering techniques do not appear very superior to conventional pressureless sintering. Sintering of tricalcium phosphate or biphasic calcium phosphates is also discussed. The chemical composition of calcium phosphate influences the behaviour. Similarly, ionic substitutions in hydroxyapatite or in tricalcium phosphate create lattice defects that modify the sintering rate. Depending on their nature, they can either accelerate or slow down the sintering rate. The thermal stability of compounds at the sintering temperature must also be taken into account. Controlled atmospheres may be required to prevent thermal decomposition, and flash sintering techniques, which allow consolidation at low temperature, can be helpful. PMID:23212081

Champion, E

2012-12-02

251

Sintering of Lunar and Simulant Glass  

NASA Astrophysics Data System (ADS)

Most oxygen-extraction techniques are temperature-dependent, with specific temperatures resulting in optimized oxygen yield. An example is hydrogen reduction, in which the optimum process temperature is 1050 C. However, glass-rich lunar soil begins to show the effects of sintering at temperatures of 900 C or lower. Sintering welds particles together due to viscous relaxation of the glass in the sample. One approach to avoid problems related to sintering, such as difficulty in removing waste material from the reactor, is to keep the soil in motion. One of several methods being studied to accomplish this is fluidized-bed processing techniques, in which the grains are kept in motion by the action of flowing reductant gas. The spent material can be removed from the chamber while still fluidized, or the fluidizing motion can continue until the material has cooled below ~500 C. Until end-to-end prototypes are built that can remove the heated soil, the most practical option is to keep the bed fluidized while cooling the waste material. As ISRU technology advances, another option will become valuable, which is to intentionally sinter the material to a great enough extent that it becomes a brick. The free iron in lunar soil is magnetic, and ferromagnetic bricks can be manipulated by robotic systems using electromagnetic end effectors. Finally, if an electromagnetic field is applied to the soil while the brick is being formed, the brick itself will become a magnet. This property can be used to create self-aligning bricks or other building materials that do not require fasteners. Although sintering creates a challenge for early lunar surface systems, knowledge gained during prototype development will be valuable for the advanced lunar outpost.

Cooper, Bonnie L.

2008-01-01

252

Leaching of molybdenum and arsenic from uranium ore and mill tailings  

USGS Publications Warehouse

A sequential, selective extraction procedure was used to assess the effects of sulfuric acid milling on the geochemical associations of molybdenum and arsenic in a uranium ore blend, and the tailings derived therefrom. The milling process removed about 21% of the molybdenum and 53% of the arsenic initially present in the ore. While about one-half of the molybdenum in the ore was water soluble, only about 14% existed in this form in the tailings. The major portion of the extractable molybdenum in the tailings appears to be associated with hydrous oxides of iron, and with alkaline earth sulfate precipitates. In contrast with the pattern seen for molybdenum, the partitioning of arsenic into the various extractable fractions differs little between the ore and the tailings. ?? 1984.

Landa, E. R.

1984-01-01

253

Sintering of Synroc D  

SciTech Connect

Sintering has been investigated as a method for the mineralization and densification of high-level nuclear defense waste powder. Studies have been conducted on Synroc D composite powder LS04. Optimal densification has been found to be highly dependent on the characteristics of the starting material. Powder subjected to milling, which was believed to reduce the level of agglomeration and possibly particle size, was found to densify better than powder not subjected to this milling. Densities of greater than 95% of theoretical could be achieved for samples sintered at 1150 to 1200/sup 0/C. Mineralogy was found to be as expected for Synroc D for samples sintered in a CO/sub 2//CO atmosphere where the Fe/sup +2//Fe/sup +3/ ratio was maintained at 1.0 to 5.75. In a more oxidizing, pure CO/sub 2/ atmosphere a new phase, not previously identified in Synroc D, was found.

Robinson, G.

1982-06-01

254

Microwave sintering of multiple articles.  

National Technical Information Service (NTIS)

Disclosed are apparatus and method for producing articles of alumina and of alumina and silicon carbide in which the articles are sintered at high temperatures using microwave radiation. The articles are placed in a sintering container which is placed in ...

R. D. Blake J. D. Katz

1992-01-01

255

SinterHab  

NASA Astrophysics Data System (ADS)

This project describes a design study for a core module on a Lunar South Pole outpost, constructed by 3D printing technology with the use of in-situ resources and equipped with a bio-regenerative life support system. The module would be a hybrid of deployable (CLASS II) and in-situ built (CLASS III) structures. It would combine deployable membrane structures and pre-integrated rigid elements with a sintered regolith shell for enhanced radiation and micrometeorite shielding. The closed loop ecological system would support a sustainable presence on the Moon with particular focus on research activities. The core module accommodates from four to eight people, and provides laboratories as a test bed for development of new lunar technologies directly in the environment where they will be used. SinterHab also includes an experimental garden for development of new bio-regenerative life support system elements. The project explores these various concepts from an architectural point-of-view particularly, as they constitute the building, construction and interior elements. The construction method for SinterHab is based on 3D printing by sintering of the lunar regolith. Sinterator robotics 3D printing technology proposed by NASA JPL enables construction of future generations of large lunar settlements with little imported material and the use of solar energy. The regolith is processed, placed and sintered by the Sinterator robotics system which combines the NASA ATHLETE and the Chariot remotely controlled rovers. Microwave sintering creates a rigid structure in the form of walls, vaults and other architectural elements. The interior is coated with a layer of inflatable membranes inspired by the TransHab project. The life-support system is mainly bio-regenerative and several parts of the system are intrinsically multifunctional and serve more than one purpose. The plants for food production are also an efficient part of atmosphere revitalization and water treatment. Moreover, the plants will be used as a "winter garden" for psychological and recreational purposes. The water in the revitalization system has a multifunctional use, as radiation shielding in the safe-haven habitat core. The garden module creates an artificial outdoor environment mitigating the notion of confinement on the lunar surface. Fiber optics systems and plasma lamps are used for transmission of natural and artificial light into the interior.

Rousek, Tom; Eriksson, Katarina; Doule, Ond?ej

2012-05-01

256

Conical O-ring seal  

SciTech Connect

A shipping container for radioactive or other hazardous materials has a conical-shaped closure containing grooves in the conical surface thereof and an O-ring seal incorporated in each of such grooves. The closure and seal provide a much stronger, tighter and compact containment than with a conventional flanged joint.

Chalfant, G.G. Jr.

1984-08-14

257

Gaseous reduction of laterite ores  

NASA Astrophysics Data System (ADS)

Lateritic nickel ores have been reduced under laboratory conditions. The reduction experiments were carried out at temperatures from 500 C to 1100 C in a horizontal tube furnace using various mixtures of H2 and CO2. The hydrogen evolution method was used to measure the degree of metallization of the reduced ore. It was found that the rate of reduction was very low at 500 C but then increased rapidly upon heating the ore to 600 C. The percent metallics increased with increasing H2 to CO2 ratios in the reducing gas. At temperatures between 600 C and 1100 C, a H2 to CO2 ratio of 3 leads to the formation of 5 to 6 pct metallics in the reduced calcine was shown. Heating the ore in air or nitrogen prior to reduction does not affect the degree of metallization. A H2 to CO2 ratio of at least 4 is required to obtain a ferronickel product analyzing 36 pct nickel if no further reduction is carried out during the subsequent smelting operation.

Utigard, T.; Bergman, R. A.

1993-04-01

258

Sintering Atmosphere Effects on the Ductility of W- Ni- Fe Heavy Metals  

NASA Astrophysics Data System (ADS)

Residual porosity has a strong negative effect on the ductility of tungsten-nickel-iron heavy metals. This investigation examines the sintering atmosphere role in stabilizing detrimental residual pore structures. Two types of experiments are reported on alloys containing 93, 95, or 97 wt pct W with Ni:Fe ratios of 7:3. The negative effect of prolonged sintering is attributed to pore coarsening involving trapped gas in the pores. Calculated pore growth rates for hydrogen filled pores suggest that pore coarsening involves both ripening and coalescence driven by tungsten grain growth. The effect of the sintering atmosphere is analyzed for final stage pore elimination. It is demonstrated that a change in sintering atmosphere from hydrogen to argon midway through the sintering cycle can aid pore degassing and increase the sintered ductility and strength.

German, R. M.; Churn, K. S.

1984-04-01

259

Endogenic Au-Ag polymetallic ore deposits and ore-bearing potentiality of strata  

Microsoft Academic Search

The problem of ore-bearing potentiality of the strata involves metallogenic theory and ore-search orientation. Studies of\\u000a the spatial distribution of endogenic Au-Ag polymetallic ore deposits in North Hebei indicated that the strata in which ore\\u000a deposits occurred range in age from Paleozoic, Proterozoic to Mesozoic. In addition the ore deposits are characterized as\\u000a being strata-bound in nature. The arise and

Baode Wang; Shuyin Niu; Aiqun Sun; Yan Xie; Yi Luo; Hailong Liu; Yanhua Wang

2010-01-01

260

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...

261

Sintered metal sand screen  

SciTech Connect

This patent describes a well screen for separating unconsolidated material out of inflowing well fluid in water, oil, gas and recovery wells. It comprises a tubular, porous body of sintered powdered metal, the tubular well screen body having an external surface which has been smoothed by electropolishing.

Arterbury, B.A.; Spangler, J.E.

1992-02-18

262

Adhesion to Sintered Substrates  

Microsoft Academic Search

Although the consensus is that various forms of specific adhesion are prevalent in most adhesive systems, the importance of mechanical adhesion should not be overlooked. Cylindrical substrates of stainless steel, both the dense metal and in sintered form, have been bonded with a polyurethane adhesive and subjected to torsional shear loading. Overall strain and load at failure are considerably higher

Martin E. R. Shanahan; Alun E. P. Morris

1996-01-01

263

Sintered Composite Filter.  

National Technical Information Service (NTIS)

A particulate filter medium formed of a sintered composite of 0.5 micrometer diameter quartz fibers and 2 micrometer diameter stainless steel fibers is described. Preferred composition is about 40 vol.% quartz and about 60 vol.% stainless steel fibers. Th...

W. Bergman

1986-01-01

264

Method of processing aluminous ores  

DOEpatents

A method of producing aluminum chloride from aluminous materials containing compounds of iron, titanium and silicon comprising reacting the aluminous materials with carbon and a chlorine-containing gas at a temperature of about 900.degree. K. to form a gaseous mixture containing chlorides of aluminum, iron, titanium and silicon and oxides of carbon; cooling the gaseous mixture to a temperature of about 400.degree. K. or lower to condense the aluminum chlorides and iron chlorides while titanium chloride and silicon chloride remain in the gas phase to effect a separation thereof; heating the mixture of iron chlorides and aluminum chlorides to a temperature of about 800.degree. K. to form gaseous aluminum chlorides and iron chlorides; passing the heated gases into intimate contact with aluminum sulfide to precipitate solid iron sulfide and to form additional gaseous aluminum chlorides; and separating the gaseous aluminum chloride from the solid iron sulfide.

Loutfy, Raouf O. (Naperville, IL); Keller, Rudolf (Murrysville, PA); Yao, Neng-Ping (Clarendon Hills, IL)

1981-01-01

265

Structure formation during the sintering of powder steels alloyed with copper, chromium, and phosphorous  

SciTech Connect

The process of structure formation during the sintering of powder steels alloyed with copper, chromium, and phosphorous was investigated. The microstructure of the materials, and distribution of alloying elements in the iron grains, were studied by the methods of electron and scanning electron microscopy. The effect of dispersion of the ferrochromium powder on its solubility in iron was examined.

Romanov, S.M. [Kirov Factory for the Manufacture of Articles from Metal Powder, Kirov (Russian Federation)

1995-11-01

266

Electrostatic beneficiation of gold ores  

Microsoft Academic Search

The authors present encouraging results obtained in separation of the Doyon gold ores when using the electrostatic inverted roof apparatus described by I.I. Inculer et al. (ibid., vol.IA-9, no.3, p.318-23, 1983). The electrification phenomena through combined tribo-electric and inductive charging were studied at various relative humidities. Contrary to expectations, the experimental work showed that the best separations are achieved at

I. I. Inculet; G. S. P. Castle; R. M. Quigley; K. J. Hodgson

1988-01-01

267

Sintered wire cathode  

DOEpatents

A porous cathode structure is fabricated from a plurality of wires which are placed in proximity to each other in elevated temperature and pressure for a sintering time. The sintering process produces the porous cathode structure which may be divided into a plurality of individual porous cathodes, one of which may be placed into a dispenser cathode support which includes a cavity for containing a work function reduction material such as BaO, CaO, and Al.sub.2O.sub.3. The work function reduction material migrates through the pores of the porous cathode from a work replenishment surface adjacent to the cavity of the dispenser cathode support to an emitting cathode surface, thereby providing a dispenser cathode which has a uniform work function and therefore a uniform electron emission.

Falce, Louis R. (San Jose, CA); Ives, R. Lawrence (Saratoga, CA)

2009-06-09

268

Sintered composite filter  

DOEpatents

A particulate filter medium formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers is described. Preferred composition is about 40 vol.% quartz and about 60 vol.% stainless steel fibers. The media is sintered at about 1100/sup 0/C to bond the stainless steel fibers into a cage network which holds the quartz fibers. High filter efficiency and low flow resistance are provided by the smaller quartz fibers. High strength is provided by the stainless steel fibers. The resulting media has a high efficiency and low pressure drop similar to the standard HEPA media, with tensile strength at least four times greater, and a maximum operating temperature of about 550/sup 0/C. The invention also includes methods to form the composite media and a HEPA filter utilizing the composite media. The filter media can be used to filter particles in both liquids and gases.

Bergman, W.

1986-05-02

269

SINTERING METAL OXIDES  

DOEpatents

A process is given for producing uranium dioxide material of great density by preparing a compacted mixture of uranium dioxide and from 1 to 3 wt.% of calcium hydride, heating the mixture to at least 675 deg C for decomposition of the hydride and then for sintering, preferably in a vacuum, at from 1550 to 2000 deg C. Calcium metal is formed, some uranium is reduced by the calcium to the metal and a product of high density is obtained.

Roake, W.E.

1960-09-13

270

Utilisation of sinter-hardening treatment for various sintered steels  

Microsoft Academic Search

Purpose: Purpose of this paper was to present the benefits of powder metallurgy technology and development of sinter-hardening process applied to different steels including pre-alloyed Ni-Mo steels with W addition, Astaloy CrM and experimental sintered duplex stainless steels. The mechanical properties, focusing in particular on hardness and wear resistance, of two different sinter-hardened steels were described. Microstructure characteristic of produced

L. A. Dobrza?ski a; J. Otr?ba; Z. Brytan; M. Rosso

271

Multi-element and mineralogical analysis of mineral ores using laser induced breakdown spectroscopy and chemometric analysis  

NASA Astrophysics Data System (ADS)

In the mining industry the quality and extent of an ore body is determined on the basis of routine assays conducted on drill core and chip samples. Both the elemental composition and the mineralogical classification are important in the characterisation of an ore body for commercial exploitation. Mining industry laboratories typically analyse large numbers of samples from both exploration and mine production environments. At CSIRO we have explored the application of chemometric methods of analysis in combination with laser induced breakdown spectroscopy (LIBS) in order to produce routine quantitative analysis of several ore types including iron, nickel and lead/zinc ores. In particular, principal components regression (PCR) has been applied to perform multi-element analysis of iron ore samples from Australia and West Africa. Calibration models for iron (4.8% Av. Relative Error), aluminium (2.2%), silicon (3.7%) and potassium (1.4%) were determined for the Australian ores. In addition phosphorous measurements were made at trace level for samples from West Africa (5.5% Av. Relative Error). LIBS measurements of segments of a nickel drill core were also analysed using PCR. Mineralogical classification using a combination of LIBS and principal components analysis (PCA) has also been explored. Broad discrimination of ore mineralogy was demonstrated on the basis of the PCA of LIBS spectra in selected emission wavelength bands. The combination of PCA and PCR offers potential for both broad mineralogical and elemental analysis for the minerals industry in exploration and in mine production for the on-line monitoring of ore quality.

Death, D. L.; Cunningham, A. P.; Pollard, L. J.

2009-10-01

272

Natural radionuclide concentrations in two phosphate ores of east Algeria.  

PubMed

Ore is considered as an important source of many elements such as the iron, phosphorus, and uranium. Concerning the natural radionuclides, their concentrations vary from an ore to other depending on the chemical composition of each site. In this work, two phosphate ores found in East of Algeria have been chosen to assess the activity concentration of natural radionuclides represented mainly by three natural radioactive series (238)U, (235)U and (232)Th, and the primordial radionuclide (40)K where they were determined using ultra-low background, high-resolution gamma-ray spectroscopy. The measured activity concentrations of radioactive series ranged from 6.2 +/- 0.4 to 733 +/- 33 Bq.kg(-1) for the (232)Th series, from 249 +/- 16 to 547 +/- 39 Bq.kg(-1) for the (238)U series, around 24.2 +/- 2.5 Bq.kg(-1) for the (235)U series, and from 1.4 +/- 0.2 to 6.7 +/- 0.7 Bq.kg(-1) for (40)K. To assess exposure to gamma radiation in the two ores, from specific activities of (232)Th, (40)K and (226)Ra, three indexes were determined: Radium equivalent (Ra(eq)), external and internal hazard indexes (H(ex) and H(in)), their values ranged from 831 +/- 8 to 1298 +/- 14 Bq.kg(-1) for Ra(eq), from 2.2 +/- 0.4 to 3.5 +/- 0.7 Bq.kg(-1) for H(ex), and from 4.2 +/- 0.7 to 4.5 +/- 0.7 Bq.kg(-1) for H(in). PMID:20303630

Lakehal, Ch; Ramdhane, M; Boucenna, A

2010-03-19

273

Low-temperature sintering of Ni-Zn-Cu ferrite and its permeability spectra  

NASA Astrophysics Data System (ADS)

The low-temperature sintering of Ni-Zn-Cu ferrite was investigated using the usual ceramic technique. We found that the post-sintering density and the permeability of the sintered ferrite are strongly affected by the size of the starting oxide powders and the pre-sintering temperature. The most effective method of preparing high-permeability ferrite is to utilize fine particles of iron oxide and to calcine at about 800C. Sintered ferrite with a density greater than 4.5 g/cc and a permeability at 10 MHz greater than 200 can be obtained at a relatively low sintering temperature (about 900C). This condition is suitable for producing multilayer chip inductors. Additionally, the complex permeability of sintered ferrite was well-described as the summation of the spin rotational contribution and the domain wall motion component. The permeability in the 100 MHz region was determined mainly by the spin rotation magnetizing mechanism and then it depended only on the ferrite volume loading, i.e. the post-sintering density. However, the contribution of the domain wall motion was not negligible in the 10 MHz region and the domain wall contribution was controlled both by altering the post-sintering density and by varying the ferrite grain size.

Nakamura, T.

1997-04-01

274

Zone sintering of ceramic fuels  

DOEpatents

Cold pressed UC.sub.2 fuel compacts are sintered at temperatures greater than about 1850.degree. C. while in contact with a sintering facilitator material, e.g., tantalum, niobium, tungsten or a metal carbide such as uranium carbide, thereby allowing for a reduction in the overall porosity and leaving the desired product, i.e., a highly dense, large-grained uranium dicarbide. The process of using the sintering facilitator materials can be applied in the preparation of other carbide materials.

Matthews, R. Bruce (Falls Church, VA); Chidester, Kenneth M. (Los Alamos, NM); Moore, H. Gene (Los Alamos, NM)

1994-01-01

275

The reaction rate at Si 3N 4\\/steel interfaces as a function of sintering aids  

Microsoft Academic Search

The solid-state interaction between Si3N4 and steels can be appraised with high temperature (10001300C) static diffusion pairs. The reaction zone thickness of the ceramic side of these couples distinguishes the chemical resistance of different Si3N4 based compositions to the attack by iron alloys. A careful selection of the amount and composition of sintering aids for Si3N4 sintering may contribute to

F. J. Oliveira; R. F. Silva; J. M. Vieira

2002-01-01

276

Recovery of Mercury from Cinnabar Ores by Electrooxidation.  

National Technical Information Service (NTIS)

An electrolytic technique for oxidizing ore slurried with brine was investigated to determine its effectiveness in extracting mercury from ores. Optimization experiments conducted on a 2.5 pound mercury per ton ore resulted in 95 percent mercury extractio...

B. J. Scheiner D. E. Shanks R. E. Linstrom

1973-01-01

277

Extrinsic magnetoresistance in bulk sintered manganites  

NASA Astrophysics Data System (ADS)

The extrinsic (intergrain) contribution to the magnetoresistance in sintered manganites strongly depends on sintering conditions. The correlations between magnetisation, resistivity and magnetoresistance are discussed.

Nossov, A.; Pierre, J.; Strobel, P.; Vassiliev, V.; Slobodin, B.; Vladimirova, E.; Machkaoutsan, V.; Ustinov, V.

1999-05-01

278

Manufacture of Sintered Silicon Nitrides.  

National Technical Information Service (NTIS)

Sintered silicon nitrides are manufactured by sintering Si3N powder containing 2 to 15% in wt of a powder mixture composed of nitride powder of lanthanide or Y 100 parts and AIN powder less than 100 parts at 1500 to 1900 deg. temperature under a pressure ...

T. Iwai

1985-01-01

279

Sintered composite medium and filter  

Microsoft Academic Search

A particulate filter medium is formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers. A preferred composition is about 40 vol. % quartz and about 60 vol. % stainless steel fibers. The media is sintered at about 1100.degree. C. to bond the stainless steel fibers into a cage network which holds

Bergman

1987-01-01

280

Microwave sintering of multiple articles  

DOEpatents

Apparatus and method for producing articles of alumina and of alumina and silicon carbide in which the articles are sintered at high temperatures using microwave radiation. The articles are placed in a sintering container which is placed in a microwave cavity for heating. The rates at which heating and cooling take place is controlled.

Blake, Rodger D. (Santa Fe, NM); Katz, Joel D. (Los Alamos, NM)

1993-01-01

281

Determination of gold in gold ores  

Microsoft Academic Search

The gold content of placer gold flakes and gold bearing ores has been determined by instrumental neutron activation analysis \\/INAA\\/ and radiochemical neutron activation analysis \\/RNAA\\/. It was discovered that significant errors result in the instrumental method for gold flakes as small as 10 mg due to sample self-absorption of neutrons during irradiation. Reliable results were obtained, for both ore

C. R. Keedy; L. Parson; J. Shen

1989-01-01

282

Radiometric Sorting of Rio Algom Uranium Ore.  

National Technical Information Service (NTIS)

An ore sample of about 0.2 percent uranium from Quirke Mine was subjected to radiometric sorting by Ore Sorters Limited. Approximately 60 percent of the sample weight fell within the sortable size range: -150 + 25 mm. Rejects of low uranium content (<0.01...

M. A. Cristovici

1983-01-01

283

Silver-iron batteries  

NASA Astrophysics Data System (ADS)

Production methods for iron electrodes were studied. It was found that a sintering temperature of 700 C gave the best strength and capacity. Production methods and additions for silver electrodes were also studied. The capacity of the produced iron and silver electrodes were 1100 mAh/cu cm. Different separators were investigated. Cellophane I and II from Du Pont was found to be the best. In tests open cells achieved 60 percent of the calculated capacity. In order to minimize the increase of the pressure in closed cells different additions to the electrodes were studied.

Lindstroem, O.

1980-04-01

284

Microbial structures in oolitic iron formations  

NASA Astrophysics Data System (ADS)

Ferriferous ooids and microoncoids occur in many sedimentary iron formations. These ferriferous-coated grains are found in fine-grained carbonate-rich groundmasses. Iron mineral-encrusted microbiota are observed in both the coated grains and the groundmass. The branching nature and other morphological features of the microorganisms suggest fungal origins for the oolitic iron ores particularly of the Lower Jurassic (Lorraine Minette). The similarity of the microbial structures in coated grains and their groundmasses suggests that both had developed within microbial mats growing under calm environmental conditions. The contribution of stromatolitic marine fungal mats to the fast extraction and immobilization of iron and thus to the genesis of iron ores is demonstrated. Observations on well-preserved freshwater-derived fungal stromatolites of the Tertiary and laboratory experiments with organotrophic fungal mats confirm the findings on the Jurassic and imply a general role of microorganisms in the formation of such deposits.

Dahanayake, Kapila; Krumbein, Wolfgang E.

1986-04-01

285

[Structural changes in mineral phases and environmental release behavior of arsenic during sintering of arsenic-containing waste].  

PubMed

An experimental work was carried out to investigate the effect of sintering temperature on arsenic volatility, arsenic leaching of the sinter and structural changes in mineral phases of arsenic in the sinter. The raw materials were shaped under the pressure of 10 MPa and sintered at 1 000-1 350 degrees C for 60 min with the air flow rate of 2 000 mL x min(-1). The results showed that there was little impact between the volatilization of arsenic before and after sintering, and arsenic fixed-rate remained above 90%, however, the sintering temperature had an important influence on the leaching concentration of arsenic. When sintering temperature was lower than 1 000 degrees C, FeAsS was oxidized into calcium arsenate, aluminum arsenate, and iron-arsenate. Ca3 (AsO4)2 was the main compound, and the release of arsenic leaching was high. When sintering temperature was up to 1 200 degrees C, the arsenic was surrounded by a glass matrix and became chemically bonded inside the matrix. Arsenates can be converted into silicoarsenates during sintering, which led to the leaching of arsenic was significantly lower. Considering the product's environmental safety, the best sintering temperature was 1 200 degrees C. PMID:23379173

Wang, Xing-Run; Nong, Ze-Xi; Wang, Qi

2012-12-01

286

Computer simulation of nanoparticle sintering  

NASA Astrophysics Data System (ADS)

Molecular Dynamics techniques were used to simulate Cu nanoparticle arrays at different temperatures. New potential was modified to provide the reliable representation of Cu nanoparticle systems. Different sets of simulation arrays were used to study the different stages of nanoscale sintering. The results are summarized as follows: (1) Three new mechanisms were found to contribute significantly to the early stage sintering. They are plastic deformation, mechanical rotation and amorphisation-recrystallization. Mechanical rotation, caused by large atomic forces relative to the particle masses, appeared to be almost independent of temperature. Plastic deformation was found to involved via dislocation generation and transmission and appeared almost athermal as well. Amorphisation of sub-critical grains was found to significantly increase the diffusion rates in the affected regions and dramatically accelerate the sintering kinetics and grain boundary kinetics. A high-speed plastic deformation, twinning, was found in the nanosphere sintering and resulted in sintered clusters with multiply twinned particles. (2) Only two of the six classical mechanisms (surface diffusion and grain boundary diffusion) were found to be important for nanoscale sintering. However, the processes were considerably accelerated by strong interatomic attractions, and depended only weakly on temperature. These "force-driven" diffusions are different from the standard "random walk" ones, and need to be treated quite differently. (3) Large array simulations are made possible by using pressure clamp technique. The effect of grain size distribution, temperature and pressure were investigated. Residual pores were found playing important role in fully densification. (4) Classical sintering laws, such as Herring's law, were found invalid to describe nanoscale sintering due to the facts that a series of mechanisms co-exists and come intro play in an overlapping manner in a short period of time. (5) Sintering Diagrams, estimated from the simulation results, appear to be differently from the ones that are predicted by the classical theory.

Zeng, Pei

287

A kinetic study of the leaching of a Nigerian ilmenite ore by hydrochloric acid  

Microsoft Academic Search

A kinetic study of the leaching of powdered ilmenite ore by hydrochloric acid has been investigated. The effects of (a) stirring speed ranging from 100 to 500 min?1, (b) particle size ranging from 20 to 74 ?m, (c) acid concentration ranging from 7.2 to 9.6 M and (d) temperature ranging from 70 to 90C on titanium and iron dissolution are

Edward Olanipekun

1999-01-01

288

36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ...  

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

36. ORE DOCK, LOOKING WEST. HULETT UNLOADERS AWAIT THE NEXT ORE BOAT. BY LATE WINTER, THE ORE STORAGE YARD SEEN AT LEFT WILL BE DEPLETED. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

289

25. FRONT END LOADERS MOMENTARILY IN REPOSE IN THE ORE ...  

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

25. FRONT END LOADERS MOMENTARILY IN REPOSE IN THE ORE STORAGE YARD. AN ORE BRIDGE THAT FORMERLY TRANSFERRED ORE WITHIN THE STORAGE YARD WAS DESTROYED BY A BLIZZARD IN 1978. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

290

Method of sintering ceramic materials  

DOEpatents

A method for sintering ceramic materials is described. A ceramic article is coated with layers of protective coatings such as boron nitride, graphite foil, and niobium. The coated ceramic article is embedded in a container containing refractory metal oxide granules and placed within a microwave oven. The ceramic article is heated by microwave energy to a temperature sufficient to sinter the ceramic article to form a densified ceramic article having a density equal to or greater than 90% of theoretical density. 2 figs.

Holcombe, C.E.; Dykes, N.L.

1992-11-17

291

Method of sintering ceramic materials  

DOEpatents

A method for sintering ceramic materials is described. A ceramic article is coated with layers of protective coatings such as boron nitride, graphite foil, and niobium. The coated ceramic article is embedded in a container containing refractory metal oxide granules and placed within a microwave oven. The ceramic article is heated by microwave energy to a temperature sufficient to sinter the ceramic article to form a densified ceramic article having a density equal to or greater than 90% of theoretical density.

Holcombe, Cressie E. (Knoxville, TN); Dykes, Norman L. (Oak Ridge, TN)

1992-01-01

292

Recovering Copper Values from Oxidized Ores.  

National Technical Information Service (NTIS)

A process is presented for recovering copper from oxidized ores such as azurite, malachite or chrysacolla. This is done by alkaline leachants having incorporated therein siliceous material to inhibit the dehydration of the formed copper complex. This perm...

P. R. Haskett D. J. Bauer C. H. Elges R. E. Lindstrom

1976-01-01

293

Research of Geochemical Associations of Nephelin Ores  

NASA Astrophysics Data System (ADS)

The instant paper concerns research of distribution petrogenic chemical members in urtit ore body of Kia-Shaltyrsk deposit. Rocks of the deposit are ore for producing alum earth. Actuality of the subject based on outlooks of detection noble metal ore-bearing (Au, Pt, Pd, Rh, Ru) in alkaline rocks of Siberia, including rocks of Kia-Shaltyrsk deposit (Kuznetsk Alatau). The main purpose of analysis of distribution of members is directed to detection of a non-uniformity of distribution of substance and segments enriched with alum earth and noble members. The basic solved problems are following: o Creation regression models of ore body; o Definition of cumulative distribution functions of members in a contour of ore body; o The analysis of the obtained outcomes in geologic terms. For construction regression models the full-scale data was used, which was presented by the results of the spectral and silicate analyses of gold and petrogenic members containing 130 assays arranged in ore body. A non-linear multiparameter model of the ore body based on components of nephelin ore using neural net approach was constructed. For each member the corresponding distribution function is produced. The model is constructed on the following members: Au, Al2O3, SiO2, Fe2O3, CaO, MgO, SO3, R2O ((Na2O+K2O) -1) and losses of burning. The error of model forecasting membersS concentrations was from 0.02 up to 20%. Large errors basically connected with assays located near contact of ore body and ad- jacent strata or with very high concentrations of members; also they can be connected with different genesis of rocks or superposition of other processes. The analysis of concentrations of members and normalised absolute errors of the fore- cast has shown, that all members can be sectioned into two groups: first: Al2O3, SiO2, R2O, Fe2O3 and second: Au, losses of burning, CaO, MgO, SO3. The distribution of 1 gold is tightly connected with calcium and losses of burning and spatially linked with zones of contact of ore body and adjacent wall rocks. Also it is possible to point, that the segments enriched with gold do not coincide with segments of high-alumna rocks but they are phase-opposite. High concentrations of alum earth, earth silicon, alkalis and low contents of ferric oxide, calcium and sulphur determine high-alumina rocks. Thus, one group of members determines high quality of nephelin ore, and the sec- ond U noble metal ore-bearing bound with members aggravating quality of nephelin ore. Therefore, it is possible to draw a conclusion, that the preliminary enrichment of nephelin ore with the help of flotation will allow to receive two kinds of high quality concentrate: aluminous and noblemetal. The research also allows developing ways of a practical solution of a problem of de- terioration quality of nephelin ore with increasing depth and, accordingly, increases its cost price. These problems apparently connected with economical planning of a production activity of the ore mine and the financial state of the alumnus plant. 2

Vulf, M.; Simonov, K.; Sazonov, A.

294

Extraction of Silver from Refractory Ores.  

National Technical Information Service (NTIS)

Silver ores from the Candelaria District, Nevada, and Round Mountain District Colorado, were investigated mineralogically and metallurgically. Silver minerals of four distinct groups were identified: (1) silver sulfide; (2) argentojarosite; (3) silver con...

B. J. Scheiner D. L. Pool J. J. Sjoberg R. E. Lindstrom

1973-01-01

295

Smelting ferroalloys by means of borate ores  

Microsoft Academic Search

Borate ore is investigated in the smelting of ferrosilicon, silicochrome, and carbon ferrochrome. A method by which high-basicity\\u000a smelting slags of refined ferrochrome may be stabilized is proposed.

A. S. Kim

2008-01-01

296

Extraction of Copper from Sulfide Ores.  

National Technical Information Service (NTIS)

In the patent application copper is extracted from sulfide ores or concentrates by electrolysis in a cell having separate anode and cathode sections, and having an intermediate liquid copper-mercury alloy electrode between the anode and cathode sections.

T. A. Henrie R. E. Lindstrom K. P. V. Lei

1976-01-01

297

8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, ...  

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

8. EAST ELEVATION OF SKIDOO MILL AND UPPER ORE BIN, LOOKING WEST FROM ACCESS ROAD. THE ROADWAY ON THIS LEVEL (CENTER) WAS USED FOR UNLOADING ORE BROUGHT ON BURROWS INTO THE ORE BIN AT THE TOP LEVEL OF THE MILL. THE ORE BIN IN THE UPPER LEFT WAS ADDED LATER WHEN ORE WAS BROUGHT TO THE MILL BY TRUCKS. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

298

Unlocking refractory gold ores and concentrates  

NASA Astrophysics Data System (ADS)

The successful treatment of gold and silver ores is always a matter of economics, but it is not always a matter of grade, or metal content. Although the photograph accompanying this article depicts the notion that the scale of gold recovery is increasingly disproportionate to the amount of earth that must be processed, the economics of gold production nonetheless provide incentives attractive enough to justify greater investment in the development of effective treatments for refractory gold ores and concentrates.

McClincy, R. J.

1990-09-01

299

Economic Census 2002: Mining, Industry Series. Iron Ore Mining.  

National Technical Information Service (NTIS)

The economic census is the major source of facts about the structure and functioning of the nation's economy. It provides essential information for government, business, industry, and the general public. Title 13 of the United States Code (Sections 131, 1...

2004-01-01

300

Post-merger time series analysis: Iron ore mining  

Microsoft Academic Search

In Brazil, mergers and acquisitions are usually analyzed by the antitrust authorities ex post, following a Structure-Conduct-Performance approach close to the US Merger Guidelines. However, this framework was unable to address the complexity posed by a series of acquisitions of four mining companies by the newly privatized national champion Companhia Vale do Rio Doce (known then as CVRD, nowadays as

Eduardo P. S. Fiuza; Fabiana F. M. Tito

2010-01-01

301

Iron and Iron Deficiency  

MedlinePLUS

... them to get enough iron from their normal diet. Women who are pregnant have higher iron needs. To ... iron sources in the diet (e.g., vegetarian diets) Low absorption Taking antacids beyond ... Young children and pregnant women are at higher risk of iron deficiency because ...

302

Estimation and characterization of PCDD/Fs and dioxin-like PCBs from Chinese iron foundries.  

PubMed

The iron foundry industry is considered to be a potential source of polychlorinated dibenzo-p-dioxins and dibenzofurans (PCDD/Fs). This study investigated the emission factors and total emission amounts of PCDD/Fs and dioxin-like polychlorinated biphenyls (DL-PCBs) from iron foundries in China. The concentrations and the World Health Organization toxicity equivalents (WHO-TEQs) are presented and the congener profiles are discussed in this paper. In the present work, 26 fly ash samples were collected and tested to quantify the PCDD/Fs and DL-PCBs generated by 14 plants of different scales, and five stack gas samples were collected from two (named as EFG and LFG) of those plants. The emission levels of PCDD/Fs and DL-PCBs indicated that hot-air cupolas had lower emissions than cold-air cupolas. When iron ore lump and sinter were used as raw material, the emission factors were about 250ng TEQt(-1) of product. However, if the raw material was scrap, the emission factors varied owing to the different contents of organic materials in the raw materials. It was found that the mean WHO-TEQ values of PCDD/Fs and DL-PCBs were 144 and 34.2pgNm(-3) in stack gas and 20.0 and 1.58pgg(-1) in fly ash. In multiple tests, it was estimated that the mean emission factors of PCDD/Fs and DL-PCBs were 365 and 10.9ng WHO-TEQt(-1) released to residue and 2719 and 555ng TEQt(-1) released to air. The total emission amounts of PCDD/Fs and DL-PCBs from Chinese iron foundries with cupola furnaces released to residue and air were 16.8 and 146g WHO-TEQ in 2008, respectively. PMID:21075413

Lv, Pu; Zheng, Minghui; Liu, Guorui; Liu, Wenbin; Xiao, Ke

2010-11-13

303

Iron versus Copper II. Principles and Applications in Bioinorganic Chemistry.  

ERIC Educational Resources Information Center

|Discusses the differences between iron and copper. Describes various aspects of the behaviors of these two elements, including those of biological and environmental significance. Addresses the evolution of the atmosphere and sedimentary ore formation, the phylogeny of iron and copper, and some anthropological notes regarding the use of the

Ochiai, Ei-Ichiro

1986-01-01

304

Ceramic surfaces and sintering  

SciTech Connect

We produced ultrafine faceted alumina particles (UFPs), 20--50 nm in diameter, by an arc-discharge method and sintered small clusters of them as they were carried through a tube furnace by flowing gas. The experiment was conducted under near UHV clean environment and specimens were examined in a UHV H9000 TEM. The UFPs produced in this study were transition alumina phases ({gamma}{delta} and {theta}). We found new {delta} and {theta} phases which were different from those in earlier studies. We developed two computer programs to simulate the shape, 3-D arrangement, and random contact of UFPs. Gaps were discovered to exist between particles due to random contact and possibly rotation and slip after contact. As no shrinkage was found, surface diffusion was identified as the dominant mechanism that was responsible for the formation of necks'' by filling in the gaps. These necks had well-defined, atomically-sharp contact angles, which suggest that the neck growth process was controlled by faceting.

Marks, L.D.

1991-08-01

305

A REAL-TIME COAL CONTENT/ORE GRADE (C2OC) SENSOR  

SciTech Connect

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 pathfinder 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.

Rand Swanson

2005-04-01

306

Method of making bonded or sintered permanent magnets  

DOEpatents

An isotropic permanent magnet is made by mixing a thermally responsive, low viscosity binder and atomized rare earth-transition metal (e.g., iron) alloy powder having a carbon-bearing (e.g., graphite) layer thereon that facilitates wetting and bonding of the powder particles by the binder. Prior to mixing with the binder, the atomized alloy powder may be sized or classified to provide a particular particle size fraction having a grain size within a given relatively narrow range. A selected particle size fraction is mixed with the binder and the mixture is molded to a desired complex magnet shape. A molded isotropic permanent magnet is thereby formed. A sintered isotropic permanent magnet can be formed by removing the binder from the molded mixture and thereafter sintering to full density.

McCallum, R.W.; Dennis, K.W.; Lograsso, B.K.; Anderson, I.E.

1993-08-31

307

Rare earth-iron-boron-permanent magnets  

SciTech Connect

This patent describes a neodymium-iron-boron permanent magnet containing added rare earth oxide. It is prepared by the method of comprising the steps of: mixing together components: a particulate alloy consisting essentially of neodymium, iron, cobalt, and boron; and a particulate rare earth oxide selected from the group consisting of gadolinium oxide, terbium oxide, dysprosium oxide, holmium oxide, and mixtures thereof; aligning magnetic domains of the mixture in a magnetic field; compacting the aligned mixture to form a shape; sintering the compacted shape; and annealing the sintered shape.

Ghandehari, M.H.

1990-08-28

308

Cold and hot deformation and densification studies on sintered Fe-C-Cr-Ni low alloy P\\/M steels  

Microsoft Academic Search

The present research work pertains to the study of the densification behaviour of sintered low alloy P\\/M steels with Ni and\\u000a Cr during cold and hot deformation processing. Elemental powders of atomized iron, graphite, chromium and nickel were mixed\\u000a in suitable proportions using a ball mill, compacted and sintered in order to yield the following alloy compositions: Fe-0.2%\\u000a C, Fe-0.2%

D. Shanmugasundaram; R. Chandramouli; T. K. Kandavel

2009-01-01

309

Geochronology and stable isotope signature of alteration related to hydrothermal magnetite ores in Central Anatolia, Turkey  

NASA Astrophysics Data System (ADS)

Hydrothermal iron ores at Divri?i, east Central Anatolia, are contained in two orebodies, the magnetite-rich A-kafa and the limonitic B-kafa (resources of 133.8 Mt with 56% Fe and 0.5% Cu). The magnetite ores are hosted in serpentinites of the Divri?i ophiolite at the contact with plutons of the Murmano complex. Hydrothermal biotite from the Divri?i A-kafa yield identical weighted mean plateau ages of 73.75 0.62 and 74.34 0.83 Ma (2?). This biotite represents a late alteration phase, and its age is a minimum age for the magnetite ore. Similar magnetite ores occur at Hasanelebi and Karakuz, south of Divri?i. There, the iron ores are hosted in volcanic or subvolcanic rocks, respectively, and are associated with a voluminous scapolite amphibole biotite alteration. At Hasanelebi, biotite is intergrown with parts of the magnetite, and both minerals formed coevally. The weighted mean plateau ages of hydrothermal biotite of 73.43 0.41 and 74.92 0.39 Ma (2?), therefore, represent mineralization ages. Hydrothermal biotite from a vein cutting the scapolitized host rocks south of the Hasanelebi prospect has a weighted mean plateau age of 73.12 0.75 Ma (2?). This age, together with the two biotite ages from the Hasanelebi ores, constrains the minimum age of the volcanic host rocks, syenitic porphyry dikes therein, and the scapolite alteration affecting both rock types. Pyrite and calcite also represent late hydrothermal stages in all of these magnetite deposits. The sulfur isotope composition of pyrite between 11.5 and 17.4 ?34S(VCDT) points towards a non-magmatic sulfur source of probably evaporitic origin. Calcite from the Divri?i deposit has ?18O(VSMOV) values between +15.1 and +26.5 and ?13C(VPDB) values between -2.5 and +2.0, which are compatible with an involvement of modified marine evaporitic fluids during the late hydrothermal stages, assuming calcite formation temperatures of about 300C. The presence of evaporite-derived brines also during the early stages is corroborated by the pre-magnetite scapolite alteration at Divri?i, and Hasanelebi-Karakuz, and with paleogeographic and paleoclimatic reconstructions. The data are compatible with a previously proposed genetic model for the Divri?i deposit in which hydrothermal fluids leach and redistribute iron from ophiolitic rocks concomitant with the cooling of the nearby plutons.

Marschik, Robert; Spikings, Richard; Ku?cu, Ilkay

2008-01-01

310

Low temperature sintering of PNSZT.  

SciTech Connect

Pb-based ferroelectrics are useful because of their large dielectric constants, high polarization values, and strong piezoelectric coefficients, but typically require sintering temperatures >1200 C, which leads to loss of the volatile Pb cation and necessitates the use of Pt electrodes for cofired parts. Reduced sintering temperatures can minimize lead loss and enable the use of cheaper electrodes, but must not sacrifice electrical performance. A systematic study of dopants to lower the sintering temperature of PNSZT (Pb0.992 (Zr0.815 Ti0.05 Sn0.135)0.9845 Nb0.155 O3) led to densities greater than 98.5% of theoretical at temperatures as low as 1100 C with as little as 0.2 wt% of a Pb glass additive or as high as 98% at 900 C with Cu2O additions with equivalent electrical properties to undoped materials.

Young, Amanda L.; Zschiesche, Dale J.; Moore, Roger Howard; Roesler, Alexander William; Hutchinson, Michael Andrew

2009-01-01

311

Mortality among sulfide ore miners  

SciTech Connect

Lung cancer mortality was studied during 1965-1985 in Outokumpu township in North Karelia, where an old copper mine was located. Age-specific lung cancer death rates (1968-1985) were higher among the male population of Outokumpu than among the North Karelian male population of the same age excluding the Outokumpu district (p less than .01). Of all 106 persons who died from lung cancer during 1965-1985 in Outokumpu township, 47 were miners of the old mine, 39 of whom had worked there for at least three years and been heavily exposed to radon daughters and silica dust. The study cohort consisted of 597 miners first employed between 1954 and 1973 by a new copper mine and a zinc mine, and employed there for at least 3 years. The period of follow-up was 1954-1986. The number of person-years was 14,782. The total number of deaths was 102; the expected number was 72.8 based on the general male population and 97.8 based on the mortality of the male population of North Karelia. The excess mortality among miners was due mainly to ischemic heart disease (IHD); 44 were observed, the expected number was 22.1, based on the general male population, and the North Karelian expected number was 31.2 (p less than .05). Of the 44 miners who died from IHD, 20 were drillers or chargers exposed to nitroglycerin in dynamite charges, but also to several simultaneous stress factors including PAHs, noise, vibration, heavy work, accident risk, and working alone. Altogether 16 tumors were observed in the cohort. Ten of these were lung cancers, the expected number being 4.3. Miners who had died from lung cancer were 35-64 years old, and had entered mining work between 1954 and 1960. Five of the ten lung cancer cases came from the zinc mine (1.7 expected). Three of them were conductors of diesel-powered ore trains.

Ahlman, K.; Koskela, R.S.; Kuikka, P.; Koponen, M.; Annanmaeki, M. (Department of Epidemiology and Biometry, Institute of Occupational Health, Helsinki (Finland))

1991-01-01

312

The role of milling atmosphere on microstructure and magnetic properties of a Nd12.8Fe79.8B7.4-type sintered magnet  

NASA Astrophysics Data System (ADS)

In this work, milled Nd12.8Fe79.8B7.4-type powders with three different oxygen contents were processed into sintered anisotropic magnets via a standard powder metallurgy technique. Minimizing the oxygen content within the powder material, resulted in an almost full densification in the sintered magnets even at the lower end of the sintering temperature limit. Under this condition, the amount of hard magnetic ? phase (Nd2Fe14B) was maximized in the structure of sintered bodies, which resulted in the highest energy density [BHmax] values. In the sintered magnets made from the powder with a higher oxygen content, full densification could only be obtained at the upper end of the sintering temperature limit, but at the expense of development a large proportion of free ?-iron within the structure of the magnets, which deteriorated the hard magnetic properties.

Madaah Hosseini, H. R.; Kianvash, A.

2004-10-01

313

Effect of calcination on sintering of hydroxyapatite  

Microsoft Academic Search

Four different temperatures (7001000 C) were chosen for calcination treatment of as-received hydroxyapatite powder before press forming and sintering to study the effect of calcination on the sintering behaviours. The results show that calcination treatment increases the average particle size and distribution, which changes from trimodal to monomodal. The sintering behaviours were investigated by dilatometry and density measurement. Fluidity of

Horng Yih Juang; Min Hsiung Hon

1996-01-01

314

Liquid phase sintering of tungsten composites in space: Results of tests performed in Texus  

NASA Astrophysics Data System (ADS)

Tungsten-nickel-iron composites are commersially fabricated from powders by liquid phase sintering. They consist of almost spherical tungsten particles in a matrix of nickel-iron-tungsten. A way to contribute to the understanding of the sintering mechanism and the mechanical properties is to study composites with a low amount of tungsten particles. Depending on the great difference in density between the particles and the matrix, this can only be done under microgravity. A primary sintering test of the tungsten composite was done in space using the Texus 10 modul. Prealloys were fabricated from metal powder mixtures, which were hot isostatic pressed. Liquid phase sintering of the two tungsten composites under microgravity has shown that the particles are evenly distributed and that no segregation occured due to convection. Despite an uneven distribution of the particles in the preformed specimens and the short melting period the patricle distribution has become even. Compared to short time sintering tests made on four alloys in the laboratory, the growth and separation of the particles was fast.

Ekbom, Lars B.; Eliasson, Anders

315

AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCIUS STEEL ORE MINE ...  

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

AERIAL OVERVIEW, LOOKING NORTH, WITH FORMER TCI-US STEEL ORE MINE HEADQUARTERS (BOTTOM) AND SUPERINTENDENT'S AND FOREMAN HOUSING ALONG MINNESOTA AVENUE AT CREST OF RED MOUNTAIN (TOP LEFT). - Muscoda Red Ore Mining Community, Bessemer, Jefferson County, AL

316

4. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO ...  

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

4. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO EAST. - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

317

1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM ...  

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

1. VIEW TO SOUTH (RETAINING WALL OF ORE RECEIVING PLATFORM TO LEFT). - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

318

2. VIEW TO NORTHEAST (ORE RECEIVING PLATFORM OUT OF VIEW ...  

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

2. VIEW TO NORTHEAST (ORE RECEIVING PLATFORM OUT OF VIEW TO RIGHT). - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

319

3. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO ...  

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

3. DETAIL OF ORE RECEIVING PLATFORM AND GRIZZLY, VIEW TO WEST. - Vanadium Corporation of America (VCA) Naturita Mill, Sampling Building & Ore Receiving Platform, 3 miles Northwest of Naturita, between Highway 141 & San Miguel River, Naturita, Montrose County, CO

320

Extraction of Gold from Carbonaceous Ores: Pilot Plant Studies.  

National Technical Information Service (NTIS)

Oxidation procedures based on the chlorine-hypochlorite system were investigated for improving gold recovery from carbonaceous gold ores. The oxidation pretreatment prior to cyanidation was accomplished by: (1) Addition of sodium hypochlorite to ore pulp;...

B. J. Scheiner D. G. Peterson R. E. Lindstrom W. J. Guay

1972-01-01

321

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING BOOM IN ...  

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

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING BOOM IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

322

CONTEXT VIEW SHOWING MODERN TRACKS PASSING UNDER HULETTS AND ORE ...  

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

CONTEXT VIEW SHOWING MODERN TRACKS PASSING UNDER HULETTS AND ORE YARD. LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

323

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELFUNLOADING SHIP UNLOADING ...  

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

CONTEXT VIEW ACROSS ORE YARD AT MODERN SELF-UNLOADING SHIP UNLOADING IN FRONT OF HULETTS. LOOKING SOUTHWEST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

324

Microwave sintering of boron carbide  

DOEpatents

A method for forming boron carbide into a particular shape and densifying the green boron carbide shape. Boron carbide in powder form is pressed into a green shape and then sintered, using a microwave oven, to obtain a dense boron carbide body. Densities of greater than 95% of theoretical density have been obtained. 1 tab.

Blake, R.D.; Katz, J.D.; Petrovic, J.J.; Sheinberg, H.

1988-06-10

325

Sintering of Nascent Calcium Oxide.  

National Technical Information Service (NTIS)

The paper discusses the measurement of the sintering rate of CaO in a nitrogen atmosphere at temperatures of 700-1100 C. CaO prepared from ultrapure CaCO3 was compared with an impure CaO derived from limestone. Both materials yielded an initial surface ar...

R. H. Borgwardt

1989-01-01

326

SINTERED POROUS METAL HEPA FILTER  

Microsoft Academic Search

ABSTRACT An all-metal High Efficiency Particulate Air (HEPA) filter has been recently developed as an alternative to traditional HEPA filters fabricated with conventional glass fibers. This metal filter was developed utilizing sintered porous metal media fabricated from nickel metal powder. One specific application is the potential for replacement of glass fiber HEPA filters currently used in High Level Waste (HLW)

Kenneth L. Rubow

327

Sintered beryllium-base compositions  

Microsoft Academic Search

1.The low corrosion resistance of beryllium in humid gaseous atmospheres is mainly due to hydrogen absorption. The harmful influence of hydrogen on the protective properties of oxide films may be significantly reduced by employing measures for removing hydrogen from materials or by initially establishing an impervious oxide film on the surface.2.Sintered beryllium prepared from preoxidized powders exhibits high corrosion resistance

V. E. Ivanov; V. F. Zelenskii; V. K. Khorenko; B. V. Matvienko; L. A. Kornienko

1968-01-01

328

SINTERING OF NASCENT CALCIUM OXIDE  

EPA Science Inventory

The paper discusses the measurement of the sintering rate of CaO in a nitrogen atmosphere at temperatures of 700-1100 C. CaO prepared from ultrapure CaCO3 was compared with an impure CaO derived from limestone. Both materials yielded an initial surface area of 104 sq m/g. The rat...

329

Long term sealing ability of butyl o-rings  

SciTech Connect

This article reports on accelerated aging tests carried out to anticipate the long term performance of o-rings in the Galileo spacecraft during its mission to Jupiter. This topics discussed include the impetus for the investigation, the operating conditions for the o-rings, the conditions leading to degradation of performance of the o-rings, and a prediction of the ability of the o-rings to complete their intended mission.

Ytterboe, S.N.; Catsiff, E.H.; Kelchner, R.E.

1991-10-01

330

32. INTERIOR VIEW LOOKING NORTH ON THE ORE BREAKER LEVEL. ...  

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

32. INTERIOR VIEW LOOKING NORTH ON THE ORE BREAKER LEVEL. THE ORE BREAKER, A BLAKE JAW CRUSHER, IS IN THE BOX IN THE LEFT OF THE PHOTOGRAPH, THE ORE TO BE BROKEN IS FED INTO THE OPENING ON THE FLOOR AND NEXT TO ORE BREAKER BOX. THE GRIZZLY BARS ARE ON THE RIGHT AND THE PULLEYS FROM THE POWER SYSTEM ARE OVERHEAD. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

331

Photochemical changes in cyanide speciation in drainage from a precious metal ore heap.  

PubMed

In drainage from an inactive ore heap at a former gold mine, the speciation of cyanide and the concentrations of several metals were found to follow diurnal cycles. Concentrations of the hexacyanoferrate complex, iron, manganese, and ammonium were higher at night than during the day, whereas weak-acid-dissociable cyanide, silver, gold, copper, nitrite, and pH displayed the reverse behavior. The changes in cyanide speciation, iron, and trace metals can be explained by photodissociation of iron and cobalt cyanocomplexes as the solutions emerged from the heap into sunlight-exposed channels. At midday, environmentally significant concentrations of free cyanide were produced in a matter of minutes, causing trace copper, silver, and gold to be mobilized as cyanocomplexes from solids. Whether rapid photodissociation is a general phenomenon common to other sites will be important to determine in reaching a general understanding of the environmental risks posed by routine or accidental water discharges from precious metal mining facilities. PMID:11918005

Johnson, Craig A; Leinz, Reinhard W; Grimes, David J; Rye, Robert O

2002-03-01

332

The Production, Microstructure, and Properties of Wrought Iron  

NASA Astrophysics Data System (ADS)

This paper reviews the production of wrought iron from the ore, using charcoal as a fuel, and also from cast iron. The microstructure consists of an almost pure iron, ferrite, and a slag: the different forms of these are described and examples are given. The mechanical properties and corrosion resistance are good but depend upon the orientation of the slag and other precipitates. The use of wrought iron in ancient artifacts is covered and examples are given. In conclusion it is suggested that developments in the manufacture of wrought iron had a marked effect on the progress of civilization.

Walker Vii, Robert

2002-04-01

333

Incorporation of iron in sodalite structures and their transformation into other iron containing zeolites  

Microsoft Academic Search

In the low temperature digestion of gibbsitic aluminium ores an iron content impurity phase, desilication product (DSP), will be separated from the sodium aluminate liquor. Due to its main component: (hydroxy- or carbonate-) sodalite (SOD) and amount, reaching 710% of the feedstock, the DSP is an important raw material for synthesising various zeolites. Applying the solgel technique the authors developed

Pl Fejes; Imre Kiricsi; Kristf Kovcs; Kroly Lzr; Istvn Marsi; Albert Oszk; Antal Rockenbauer; Zoltn Schay

2002-01-01

334

Process for the production of sponge iron  

US Patent & Trademark Office Database

Sponge iron is produced at a shaft furnace from iron ore, preferably in the form of pellets, whereby a hot reduction gas is passed upwardly through the shaft furnace and the iron ore descends therein. The hot reduction gas is formed in part by a desulfurized fresh gas produced by partial oxidation of a hydrocarbon (generally high sulfur residual oil) and desulfurization and, in part, by recirculated exhaust gas drawn from the head of the furnace and having its carbon-oxide content reduced by about ten volume percent. The fresh gas is mixed with the recirculated exhaust gas in a volume ratio of fresh gas/exhaust gas of 0.8:1.0 to produce a cold mixed gas. The cold mixed gas is heated to a temperature of about 1000.degree. C directly before being introduced into the shaft furnace as reduction gas.

1977-08-09

335

Dissolution kinetics of smithsonite ore in ammonium chloride solution  

Microsoft Academic Search

The results of a dissolution kinetics study of smithsonite ore in ammonium chloride are presented. Effect of stirring speed, ore particle size, reaction temperature, and the concentration of ammonium chloride on zinc dissolution rate are determined. The results obtained show that leaching of about 91.2% of zinc is achieved using 84110 ?m ore particle size at a reaction temperature of

Shaohua Ju; Tang Motang; Yang Shenghai; Li Yingnian

2005-01-01

336

29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE ...  

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

29. ORE DOCK, LOOKING WEST; AT WORK UNLOADING THE 'GEORGE M. HUMPHREY'S' CARGO OF 25,000. TONS OF ORE. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

337

18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ...  

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

18. VIEW OF CRUDE ORE BINS FROM WEST. WEST CRUDE ORE BIN AND TRESTLE FROM TWO JOHNS TRAMLINE TO SOUTH, CRUDE ORE BIN IN FOREGROUND. MACHINE SHOP IN BACKGROUND. THE TRAM TO PORTLAND PASSED TO NORTH OF MACHINE SHOP. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

338

3. EAGLE MILL, DETAIL OF CRUDE ORE BIN FROM NORTH, ...  

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

3. EAGLE MILL, DETAIL OF CRUDE ORE BIN FROM NORTH, c. 1908-10. SHOWS EXPOSED CRUSHER HOUSE IN FRONT OF (SOUTH) CRUDE ORE BIN AND SNOW SHED ADDED OVER TRAM TRACKS. NOTE LACK OF EAST OR WEST CRUDE ORE BINS. CREDIT JW. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

339

6. Looking west showing top of dock: steaming frozen ore ...  

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

6. Looking west showing top of dock: steaming frozen ore which had been put in pockets in December 1959, May 6, 1990. Photographer: unknown - Marquette Ore Dock No. 6, Ore Dock, On pilings in Marquette City Lower Harbor, Marquette, Marquette County, MI

340

Archaean lode gold mineralisation in banded iron formation at the Kalahari Goldridge deposit, Kraaipan Greenstone Belt, South Africa  

Microsoft Academic Search

The Kalahari Goldridge Mine is located within the Archaean Kraaipan Greenstone Belt, about 60 km southwest of Mafikeng in the North West Province, South Africa. The ore body thickness varies from 15 to 45 m along a strike length of about 1.5 km within approximately N-S striking banded iron formation (BIF). The stratabound ore body is hosted primarily by BIF,

Napoleon Q. Hammond; John M. Moore

2006-01-01

341

Surface melting and sintering of metallic nanoparticles.  

PubMed

The melting and sintering of two different-sized metallic nanoparticles are simulated by a molecular dynamics method in this work. The particles are partitioned into different regimes where tracing atoms are arranged to investigate the melting and sintering kinetics. The melting of individual particles is firstly investigated and compared with established studies, where the size-dependent melting depression and surface melting phenomenon are revealed. The detailed sintering process of two nickel nanoparticles, 3.52 and 1.76 nanometers in diameter respectively, is subsequently examined by the gyration radius, mean square displacement (MSD), root mean square displacement (RMSD), sintering diffusivity and activation energy. A three-stage sintering scenario is illustrated, and the layered structure shows the regime dependent behavior of diffusivity during the sintering process. Beside the surface diffusion, sintering of different-sized nanoparticles is found to be affected by a few other mechanisms. PMID:21121291

Song, Pengxiang; Wen, Dongsheng

2010-12-01

342

Oil shales, evaporites and ore deposits  

Microsoft Academic Search

The relationships between oil shales, evaporites and sedimentary ore deposits can be classified in terms of stratigraphic and geochemical coherence. Oil shale and black shale deposition commonly follows continental red beds and is in turn followed by evaporite deposition. This transgressive-regressive sequence represents an orderly succession of depositional environments in space and time and results in stratigraphic coherence. The amount

Hans P. Eugster

1985-01-01

343

Continuous Beneficiation of Dolomitic Phosphate Ores.  

National Technical Information Service (NTIS)

Over 80 pct of domestic phosphate rock, which is the starting material for phosphorus-containing fertilizers, comes from central Florida deposits. As higher grade deposits are depleted, lower grade phosphate ores containing MgO in the form of dolomite are...

B. E. Davis T. O. Llewellyn C. W. Smith

1984-01-01

344

PROCESS OF RECOVERING URANIUM FROM ITS ORES  

DOEpatents

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.

Galvanek, P. Jr.

1959-02-24

345

Metalliferous black shales and related ore deposits  

SciTech Connect

This book comprises papers and extended abstracts dealing with a variety of topics including the geochemistry and organic geochemistry of several black shale formations: the nature of modern Black Sea sediments: metal- organic complexes in ore fluids; black shales related to disseminated gold deposits; vanadium concentrations and molybdenum-nickel deposits; and the problem of defining metalliferous black shales.

Grauch, R.I. (Geological Survey, Reston, VA (United States)); Huyck, H.L.O. (Cincinnati Univ., OH (United States))

1990-01-01

346

Mechanical properties of molybdenum alloyed liquid phase-sintered tungsten-based composites  

SciTech Connect

Tungsten-based composites are fabricated from mixed elemental powders using liquid phase sintering, usually with a nickel-iron matrix. During sintering, the tungsten undergoes grain growth, leading to microstructure coarsening that lowers strength but increases ductility. Often the desire is to increase strength at the sacrifice of ductility, and historically, this has been performed by postsintering deformation. Swaging a 93W-5Ni-2Fe alloy with 15 to 20 pct area reduction gives a 1000 to 1200 MPa tensile strength, 70 HRA hardness, and 15 to 20 pct fracture elongation.

Kemp, P.B.; German, R.M.

1995-08-01

347

Rajkonkoski gold-telluride ore occurrence: A new high prospective type of complex noble metal mineralization in the Karelian Proterozoic  

NASA Astrophysics Data System (ADS)

The Rajkonkoski ore occurrence is located within the region of the Karelian craton (AR2) and the Svecofennian folded belt (PR1) conjugation. It is presented by quartz-carbonate veins in metadoleriles and a zone of brecciation, crumple, and silification of carbonaceous shales within the volcanites of the Soanlakhtinsky suite (PR1). Ore mineralization in black shales and quartz veins has features of genetic similarity presenting different levels of the ore system controlled by different range strike-slip fault dislocations. At the Rajkonkoski ore occurrence, 41 ore minerals have been identified: 12 tellurides (native tellurium, hedleyite, pilsenite, tsumoite, tellurobismuthite, hessite, stuetzite, radclidzhite, joseite-B, altaite, volynskite, petzite); 4 bismuth-tellurides of the following compositions Bi3Te, Bi3Te2, BiTe4, PbBiTe; 3 selenides (clausthalite, tellurolaitakarite, native selenium); and 12 native metals (gold, silver, electrum, copper, iron, lead, tin, bismuth, osmiridium). The contents of the main ore minerals in places exceed 10%, and the concentrations of elements reach as follows: Cu and Pb, 5%; Zn, Bi, 1%; Se, 219 ppm; Te, 171 ppm; Sb, 3 ppm; As, 5 ppm; Ag, >0.1%; Au, 35.28 ppm. Ore mineralization is formed during the temperature interval from 550C up to <170oC in the conditions of high activity of Se and Te, and beginning from medium temperatures (>300C) complete miscibilities galenite-clausthalite and galenite-altaite are observed. In aggregate with a wide temperature interval (>400C) of ore process evolution and mineral specia variety of telluride and native metal mineralizations, the original torsion of different temperature mineralizations makes it possible to determine the affiliation of the Rajkonkoski ore occurrence to the xenothermal type deposits or epithermal alkaline, gold-telluride A-type characterized by a close connection with magmatism of increased alkalinity and the original geochemical (Te-V-F) and mineral (tellurides of gold, silver and other metals, fluorite, roscoelite, vanadium-containing sulfides) associations. Taking into consideration that many of the xenothermal and epithermal A-type gold and silver deposits are large commercial objects, the prospects of the Rajkonkoski ore occurrence and the region of the Karelian craton and Svecofennian folded belt conjugation seem to be significant for noble metal mineralization.

Ivashchenko, V. I.; Sundblad, K.; Toritsin, A. N.; Golubev, A. I.; Lavrov, O. B.

2008-11-01

348

Behavior of uranium under conditions of interaction of rocks and ores with subsurface water  

NASA Astrophysics Data System (ADS)

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 inevi

Omel'Yanenko, B. I.; Petrov, V. A.; Poluektov, V. V.

2007-10-01

349

Hot-pressed polycrystalline yttrium iron garnet  

Microsoft Academic Search

A simple hot-pressing system is described which enables small volumes of polycrystalline yttrium iron garnet to be routinely produced. The products have high density, very low second phase content and a controlled grain size. Their magnetic properties compare very favourably with similar polycrystalline material produced by conventional sintering. Sample porosity may be varied in a controlled manner by simple changes

G. A. Naziripour; A. O. Tooke; K. J. Standley; B. E. Storey

1985-01-01

350

Spark plasma sintering of aluminum matrix composites  

NASA Astrophysics Data System (ADS)

Aluminum matrix composites make a distinct category of advanced engineering materials having superior properties over conventional aluminum alloys. Aluminum matrix composites exhibit high hardness, yield strength, and excellent wear and corrosion resistance. Due to these attractive properties, aluminum matrix composites materials have many structural applications in the automotive and the aerospace industries. In this thesis, efforts are made to process high strength aluminum matrix composites which can be useful in the applications of light weight and strong materials. Spark Plasma Sintering (SPS) is a relatively novel process where powder mixture is consolidated under the simultaneous influence of uniaxial pressure and pulsed direct current. In this work, SPS was used to process aluminum matrix composites having three different reinforcements: multi-wall carbon nanotubes (MWCNTs), silicon carbide (SiC), and iron-based metallic glass (MG). In Al-CNT composites, significant improvement in micro-hardness, nano-hardness, and compressive yield strength was observed. The Al-CNT composites further exhibited improved wear resistance and lower friction coefficient due to strengthening and self-lubricating effects of CNTs. In Al-SiC and Al-MG composites, microstructure, densification, and tribological behaviors were also studied. Reinforcing MG and SiC also resulted in increase in micro-hardness and wear resistance.

Yadav, Vineet

351

Investigation of extractive separation of uranium and vanadium from sulphuric acid leaching liquors of uranium ore (2). Reduction of Fe(III) from sulphuric acid.  

National Technical Information Service (NTIS)

Reduction condition of Fe(III) to extract uranium and vanadium with HDEHP from sulphuric acid leaching liquors of uranium ore was examined. It was shown that in the system of oxidation-reduction consisted of many ionic pairs can reduce Fe(III) with iron s...

Han Hi Jong

1989-01-01

352

Concentracao do minerio de terras raras de Pocos de Caldas-MG. (Concentration of rare earths ore from Pocos de Caldas - MG, Brazil).  

National Technical Information Service (NTIS)

The objective of this research was to concentrate, mainly by flotation, a rare-earth ore body. The valuable mineral is bastnaesite which occurs intimately associated with iron oxides and other gangue minerals, making difficult to get a concentrate of comm...

J. A. Sampaio F. F. Lins N. H. Porphirio

1990-01-01

353

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...

354

Sintered composite medium and filter  

DOEpatents

A particulate filter medium is formed of a sintered composite of 0.5 micron diameter quartz fibers and 2 micron diameter stainless steel fibers. A preferred composition is about 40 vol. % quartz and about 60 vol. % stainless steel fibers. The media is sintered at about 1100.degree. C. to bond the stainless steel fibers into a cage network which holds the quartz fibers. High filter efficiency and low flow resistance are provided by the smaller quartz fibers. High strength is provided by the stainless steel fibers. The resulting media has a high efficiency and low pressure drop similar to the standard HEPA media, with tensile strength at least four times greater, and a maximum operating temperature of about 550.degree. C. The invention also includes methods to form the composite media and a HEPA filter utilizing the composite media. The filter media can be used to filter particles in both liquids and gases.

Bergman, Werner (Pleasanton, CA)

1987-01-01

355

Three positive regulators of leaf senescence in Arabidopsis , ORE1, ORE3 and ORE9, play roles in crosstalk among multiple hormone-mediated senescence pathways  

Microsoft Academic Search

Leaf senescence is a developmentally programmed event, but the initiation and progression of leaf senescence are affected\\u000a by a range of plant hormones including abscisic acid (ABA), ethylene and methyl jasmonate (MeJA). To investigate plant hormone\\u000a crosstalk during leaf senescence, hormone-induced senescence phenotypes were analyzed in three leaf senescence mutants [ore1 (oresara1), ore3 and ore9] showing delayed senescence phenotypes in

Jin Hee Kim; Kyung Min Chung; Hye Ryun Woo

2011-01-01

356

Extraction process and apparatus for hydrocarbon containing ores  

SciTech Connect

There is provided a hydrocarbon extraction process and apparatus for removing hydrocarbons from a hydrocarbon containing ore such as a diatomite ore. The ore is preprocessed to the extent required to produce an extractable ore and subsequently mixed with a carrier to form an ore stream. The carrier may be a nonaqueous solvent and may further comprise a non-porous granular material such as sand. The ore stream is passed in substantially vertical countercurrent flow through a nonaqueous solvent to produce a product-solvent stream and a spent ore stream. The solvent is subsequently separated from the hydrocarbon stream, which may be further upgraded by removal of a heavy portion. This may be accomplished in the presence of a substantial amount of fines.

Friedman, R. H.; Eakin, B. E.

1985-09-03

357

DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER ...  

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

DETAIL VIEW OF LOWER TRAM TERMINAL, SECONDARY ORE BIN, CRUSHER FOUNDATION, AND BALL MILL FOUNDATIONS, LOOKING NORTH NORTHWEST. ORE FROM THE MINES WAS DUMPED FROM THE TRAM BUCKETS INTO THE PRIMARY ORE BIN UNDER THE TRAM TERMINAL. A SLIDING CONTROL DOOR INTRODUCED THE INTO THE JAW CRUSHER (FOUNDATIONS,CENTER). THE CRUSHED ORE WAS THEN CONVEYED INTO THE SECONDARY ORE BIN AT CENTER LEFT. A HOLE IN THE FLOOR OF THE ORE BIN PASSED ORE ONTO ANOTHER CONVEYOR THAT BROUGHT IT OUT TO THE BALL MILL(FOUNDATIONS,CENTER BOTTOM). THIS SYSTEM IS MOST LIKELY NOT THE ORIGINAL SET UP, PROBABLY INSTALLED IN THE MINE'S LAST OCCUPATION IN THE EARLY 1940s. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

358

Bioleaching of zinc from low-grade complex sulfide ores in an airlift by isolated Leptospirillum ferrooxidans  

Microsoft Academic Search

Bioleaching of low-grade complex sulfide ores from La Silvita and La Resbalosa (Patagonia Argentina) were carried out in a reverse flow airlift reactor by a native strain of Leptospirillum ferrooxidans (Lf-LS04). The reactor was filled with iron free 9K medium pH 1.8, with mineral particle size of 74?m, pulp density of 1% and a superficial air velocity of 0.01m s?

A. Giaveno; L. Lavalle; P. Chiacchiarini; E. Donati

2007-01-01

359

Non-Sintered Nickel Electrode  

DOEpatents

A non-sintered nickel electrode contains a conductive support and a paste comprising an electrochemically active material containing nickel hydroxide and a binder which is a mixture of an elastomer and a crystalline polymer. The proportion of the elastomer is in the range 25% to 60% by weight of the binder and the proportion of the crystalline polymer is in the range 40% to 75% by weight of the binder.

Bernard, Patrick (Massy, FR); Dennig, Corinne (Asnieres sur Seine, FR); Cocciantelli, Jean-Michel (Bordeaux, FR); Alcorta, Jose (Bordeaux, FR); Coco, Isabelle (Dax, FR)

2002-01-01

360

Pressure sintering of powder materials  

Microsoft Academic Search

Rheological models for pressure sintering of powder materials are described. The rheological models of deformable bodies and\\u000a the associated dynamic deformation theory for porous bodies based on the energy conservation law enable a quantitative description\\u000a of their densification under impulse and static hot pressing as well as hot forging using crank presses. The simulation of\\u000a compaction of porous metals shows

M. S. Kovalchenko

2011-01-01

361

Sintered composite medium and filter  

SciTech Connect

A filter media is described comprising a sintered composite of quartz fibers and stainless steel fibers having a filter efficiency of at least about 99.99% for 0.3 micron diameter particles, an operative temperature up to about 550/sup 0/C, and flow resistance comparable to and tensile strength at least four times that of a standard high efficiency particulate air filter media.

Bergman, W.

1987-08-18

362

Sintered composite medium and filter  

Microsoft Academic Search

A filter media is described comprising a sintered composite of quartz fibers and stainless steel fibers having a filter efficiency of at least about 99.99% for 0.3 micron diameter particles, an operative temperature up to about 550°C, and flow resistance comparable to and tensile strength at least four times that of a standard high efficiency particulate air filter media.

Bergman

1987-01-01

363

Silicon nitride base sintered body  

US Patent & Trademark Office Database

A sintered body of silicon nitride base solidly formed of interior and surface portions wherein the rate of decrease of the content Si or Si.sub.3 N.sub.4 and Sialon grains in the surface portion, with respect to that in the interior portion, is not less than 20% by weight or 30-100 vol %, respectively. The grain boundary phase of the surface portion is glassy, or crystallized partly or entirely. Crystallized boundary phase comprises Si.sub.3 N.sub.4 -Y.sub.2 O.sub.3 base compounds Si.sub.3 N.sub.4 -nY.sub.2 O.sub.3 -mX (n=1-5, X=SiO.sub.2, Al.sub.2 O.sub.3, m=0-4) such as mellilite, J phase (mohlerite), K phase (wollastonite), H phase (apatite), or A phase (Si.sub.3 N.sub.4.5Y.sub.2 O.sub.3.Al.sub.2 O.sub.3). Sintering aids of Al.sub.2 O.sub.3, Y.sub.2 O.sub.3, AlN, MgO, CaO, Y.sub.2 O.sub.3 and/or rare earth oxides form boundary phases. The sintered body may comprise 30% by weight or less of compounds (oxide, carbide or nitride) of subgroups IVa, Va and VIa of the International Periodic Table as third dispersed component. This sintered body with the modified surface portion exhibits the intrinsic property of the interior portion and the property of the surface portion resulting in high wear resistance and toughness useful as cutting tools.

Suzuki; Junichiro (Gifu, JP); Kayukawa; Masahide (Gifu, JP)

1994-05-31

364

Properties of nano- and microparticles emitted into the environment from open-pit mining of iron deposits  

NASA Astrophysics Data System (ADS)

The properties of nano- and microparticles (60 nm-200 ?m) of the dust formed by mass blasting in the iron ore open pit of the Lebedinsky Mining and Concentrating Combine have been studied. Data on the morphology of particles, their magnetic properties, mineralogy, and dimensions have been obtained. Quartz, magnetite, and mica were identified among these particles. The dust mostly consisted of fragmented iron ore formation from the rock massif involved in the blasting.

Adushkin, V. V.; Weidler, P. G.; Dubovskoi, A. N.; Pernik, L. M.; Popel, S. I.; Friedrich, F.

2010-10-01

365

Selective laser sintering of amorphous metal powder  

Microsoft Academic Search

For the first time, selective sintering of amorphous PtCuNiP powder with a pulsed Nd:YAG laser has been studied. Upon pulsed interaction, the grains melt only superficially to build necks between the grains. Depending on the laser parameters, the sintered material can be crystallized or retained amorphous. By contrast with crystalline powder, laser sintering of amorphous powder is achieved at substantially

P. Fischer; A. Blatter; V. Romano; H. P. Weber

2005-01-01

366

The role of viscoelasticity in polymer sintering  

Microsoft Academic Search

An experimental study for polymer sintering has been carried out using pairs of powder particles. Although in many cases\\u000a Newtonian sintering models successfully describe polymer sintering, they predict a faster coalescence rate than that observed\\u000a with the polypropylene copolymer resins used in this study, indicating that factors other than the surface tension and the\\u000a viscosity play a role in polymer

C. T. Bellehumeur; Marianne Kontopoulou; J. Vlachopoulos

1998-01-01

367

Sintering mechanism of samarium--cobalt alloys  

Microsoft Academic Search

The sintering mechanism of samarium-cobalt alloys was investigated ; employing isothermal shrinkage measurements on pre-alloyed powders and powder ; mixtures in the concentration range from 23 to 42 wt.% Sm. The sintering ; temperatures were varied from 1,020 to 1,160 deg C. The three stoichiometric ; compounds SmCO, SmCo and SmCo are characterized by ; com paratively slow sintering behavior,

G. H. Gessinger; E. de Lamotte

1973-01-01

368

Sintering and grain growth of ultrapure alumina  

Microsoft Academic Search

The kinetics of densification and grain growth of ultrapure alumina (> 99.999%) were measured for clean sintering conditions in a pure-sapphire tube, and compared with kinetics measured during normal sintering conditions in an alumina crucible of 99.8% purity. For the clean condition, the microstructure of sintered alumina remained homogeneous and only normal grain growth was observed up to 1900C for

So Ik Bae; Sunggi Baik

1993-01-01

369

Infrared analysis of refined uranium ore  

Microsoft Academic Search

Infrared assay of refined uranium ore (yellowcake) is described and the results are related to worker protection measures. Eleven standard mixtures of ammonium diuranate and UO were prepared that contained 0% ammonium diuranate (pure UO) through 100% ammonium diuranate (no UO) in 10% intervals. Assay of these mixtures (0.30% in KBr) showed that ammonium diuranate could be accurately assayed within

Arthur F. Eidson

1985-01-01

370

Preparation of magnesite ore in mining  

Microsoft Academic Search

It is shown that the chemical composition of the mined magnesite ore is interrelated with its lumpiness. It is established\\u000a that the content of harmful admixtures in fine fractions exceeds that in coarse fractions by a factor of 23. The discovered\\u000a dependences have been used in a series of full-scale tests that reflect the main laws of segregation of the

A. V. Galyanov; Yu. V. Laptev; M. N. Kovalev; A. I. Vladimirov

2000-01-01

371

Pressure leaching las cruces copper ore  

NASA Astrophysics Data System (ADS)

A hydrometallurgical process was developed for treating the Las Cruces massive sulfide-ore deposit located near Seville, Spain. A two-stage countercurrent leach process, consisting of an atmospheric leach and a pressure leach, was developed to effectively leach copper from the copper-bearing minerals and to generate a solution suitable for the subsequent solvent-extraction and copper-electrowinning operations. The results of batch and continuous miniplant tests are presented.

Berezowsky, R. M.; Xue, T.; Collins, M. J.; Makwana, M.; Barton-Jones, I.; Southgate, M.; Maclean, J. K.

1999-12-01

372

New anticorrosive coating compositions incorporated ilmenite ore  

Microsoft Academic Search

Objective of the research relates to corrosion-resistant coating capable of being lied to various substrates, particularly metal surfaces, as a single coat characterized as having high-gloss, good adhesion and a high degree of flexibility. Long oil alkyds were first modified with naphthalene dicarboxylic acid and then introduced in primer formulations containing an effective amount of corrosion-resisting pigment ilmenite ore. The

H. Abd El-Wahab; M. Abd EL-Fattah; M. I. Abdou; F. Abd El-Hai

2009-01-01

373

Selective laser sintering of amorphous metal powder  

NASA Astrophysics Data System (ADS)

For the first time, selective sintering of amorphous PtCuNiP powder with a pulsed Nd:YAG laser has been studied. Upon pulsed interaction, the grains melt only superficially to build necks between the grains. Depending on the laser parameters, the sintered material can be crystallized or retained amorphous. By contrast with crystalline powder, laser sintering of amorphous powder is achieved at substantially lower pulse energies due to its low melting point. The obtained results are compared with previous results from selective laser sintering of titanium powder.

Fischer, P.; Blatter, A.; Romano, V.; Weber, H. P.

2005-02-01

374

Bioleaching of heavy metals from a low-grade mining ore using Aspergillus niger.  

PubMed

The main concern of this study is to develop a feasible and economical technique to microbially recover metals from oxide low-grade ores. Owing to the significant quantities of metals that are embodied in low-grade ores and mining residues, these are potential viable sources of metals. In addition, they potentially endanger the environment, as the metals they contain may be released to the environment in hazardous form. Hence, mining industries are seeking an efficient, economic technique to handle these ores. Pyrometallurgical and hydrometallurgical techniques are either very expensive, energy intensive or have a negative impact on the environment. For these reasons, biohydrometallurgical techniques are coming into perspective. In this study, by employing Aspergillus niger, the feasibility of recovery of metals from a mining residue is shown. A. niger exhibits good potential in generating a variety of organic acids effective for metal solubilization. Organic acid effectiveness was enhanced when sulfuric acid was added to the medium. Different agricultural wastes such as potato peels were tested. In addition, different auxiliary processes were evaluated in order to either elevate the efficiency or reduce costs. Finally, maximum solubilization of 68%, 46% and 34% were achieved for copper, zinc and nickel, respectively. Also iron co-dissolution was minimized as only 7% removal occurred. PMID:15177728

Mulligan, Catherine N; Kamali, Mahtab; Gibbs, Bernard F

2004-07-01

375

Effect of some additions on the microstructure and mechanical, fatigue, and friction properties of sintered lead bronze  

Microsoft Academic Search

In an investigation into the effect of Zn, Ni, As, P, Fe, Sn, and Sb on the properties of sintered lead bronze with 30% Pb it was established that all the additions except iron and phosphorus increase in varying degrees the strength, hardness, and resistance to fatigue stresses of the material. All the additions adversely affect its coefficient of friction.

A. alak; V. Prochzka; E. Navara

1971-01-01

376

Gas-based iron making: feasibility study. Final report, April 1985December 1986  

Microsoft Academic Search

This paper explores the technical and economic feasibility of producing liquid iron and steel from finely ground iron ore through a natural gas based process. Raw materials represent 80% to 90% of the cost of present ironmaking processes. A substantial cost reduction can be achieved by changing the raw materials; metallurgical coke was replaced with natural gas, and pre-processed pellets

K. H. Hemsath; K. M. Jeong; V. Goldfarb; J. A. Woodroffe; D. B. Stickler

1987-01-01

377

Animal Remains from Industrial Iron Age Communities in Phalaborwa, South Africa  

Microsoft Academic Search

The Phalaborwa region in the Northern Province of South Africa has one of the richest copper- and iron-bearing deposits in southern Africa. These deposits have been worked for 1200 years and are still being worked. The abundance of ore reduction and metal production sites, dating mostly to the Late Iron Age, testifies to the importance of these deposits. Those sites

Ina Plug; J. C. C. Pistorius

1999-01-01

378

Physical-chemical conditions of ore deposition  

USGS Publications Warehouse

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.

Barton, Jr. , P. B.

1981-01-01

379

Combination of mechanical alloying and two-stage sintering of a 93W5.6Ni1.4Fe tungsten heavy alloy  

Microsoft Academic Search

The microstructural evolution and mechanical properties of a mechanically alloyed and two-stage sintered tungsten heavy alloy were investigated. Elemental powders of tungsten, nickel and iron of a composition corresponding to 93W5.6Ni1.4Fe were mechanically alloyed in a tumbler ball mill for 72 h. Mechanically alloyed powders were solid-state sintered at 1300C for 1 hr in a hydrogen atmosphere followed by secondary

Soon H Hong; Ho J Ryu

2003-01-01

380

Sintering of silicon nitride ceramics with magnesium silicon nitride and yttrium oxide as sintering aids  

Microsoft Academic Search

Silicon nitride (Si3N4) ceramics had been produced through pressureless sintering and hot-pressing sintering with MgSiN2-Y2O3 or only MgSiN2 as sintering aids. The influences of the amount of MgSiN2 and Y2O3 and sintering methods on the properties of Si3N4 ceramics were investigated. The results show that the bend strength of Si3N4 ceramic fabricated through pressureless sintering at 1820 C for 4

J. Jiang; J. Y. Xu; G. H. Peng; H. R. Zhuang; W. L. Li; S. Y. Xu; Y. J. Mao

2011-01-01

381

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE ...  

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

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE BIN, LOOKING NORTHEAST. REMAINS OF A BLACKSMITH'S FORGE AND WORK CAN BE SEEN JUST BELOW THE ORE BIN (SEE CA-291-32 FOR DETAIL). ROCK FOUNDATIONS LOCATED JUST ABOVE THE ORE BIN AND ALONG THE FIRST RIDGELINE ARE TENT PADS. SEE CA-291-24 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

382

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE ...  

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

OVERVIEW OF UPPER TRAM TERMINAL, TRAM TRESTLE, AND PRIMARY ORE BIN, LOOKING NORTHEAST. REMAINS OF A BLACKSMITH'S FORGE AND WORK CAN BE SEEN JUST BELOW THE ORE BIN (SEE CA-291-32 FOR DETAIL). ROCK FOUNDATIONS LOCATED JUST ABOVE THE ORE BIN AND ALONG THE FIRST RIDGELINE ARE TENT PADS. SEE CA-291-49 (CT) FOR IDENTICAL COLOR TRANSPARENCY. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

383

37. VIEW NORTH FROM EAST CRUDE ORE BIN TO CRUSHER ...  

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

37. VIEW NORTH FROM EAST CRUDE ORE BIN TO CRUSHER ADDITION AND CRUSHED OXIDIZED ORE BIN. VISIBLE ARE DINGS MAGNETIC PULLEY (CENTER), THE 100-TON STEEL CRUSHED UNOXIDIZED ORE BIN, AND UPPER PORTION OF THE STEPHENS-ADAMSON 25 TON/HR BUCKET ELEVATOR. THE UPPER TAILINGS POND LIES BEYOND THE MILL WITH THE UPPER TAILINGS DAM UNDER THE GRAVEL ROAD IN THE UPPER RIGHT CORNER. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

384

Techniques of copper recovery from Mexican copper oxide ore  

Microsoft Academic Search

Mexican copper ore is a mixed ore containing mainly copper oxide and some copper sulfide that responds well to flotation. The joint techniques of flotation and leaching were studied. The results indicate that an ore containing 19.01% copper could be obtained at a recovery ratio of 35.02% by using sodium sulfide and butyl xanthate flotation. Over 83.33% of the copper

Zhan-fang CAO; Hong ZHONG; Guang-yi LIU; Shu-juan ZHAO

2009-01-01

385

Hydrocarbons associated with lead-zinc ores at Laisvall, Sweden  

Microsoft Academic Search

BITUMEN and a series of normal alkanes (C18 to C27) have been identified in sphalerite from the Laisvall lead-zinc deposit. This is a stratabound lead-zinc ore in Eocambrian sandstone, situated at the eastern border of the Swedish Caledonides. The deposit is an aberrant member of the Mississippi Valley ore class1. The main ore minerals are galena and sphalerite, associated with

David T. Rickard; M. Willden; Y. MRDE; R. RYHAGE

1975-01-01

386

Ammonia as a sintering aid for UO  

Microsoft Academic Search

Ammonia is a sintering aid for UO pellets. The enhancement in densification using NH atmospheres includes a reduction in sintering temperatures and a substantial increase in grain size. A redistribution and increase in size of the porosity occurs. Calcining UO precursors (such as ammonium diuranate) in NH results in a more active powder which produces a larger grain size in

K. C. Radford; J. M. Pope

1977-01-01

387

Modeling of Nano-Tungsten Sintering Data.  

National Technical Information Service (NTIS)

Small metal samples have been made from nano-crystalline tungsten powder by sintering with the goal of producing high density parts. The parameters associated with sintering runs have been examined to see if there is an empirical relationship between them...

W. S. De Rosset

2011-01-01

388

Environmentally assisted fracture of sintered nickel cartridges  

Microsoft Academic Search

The failure of sintered Ni 200 cartridges, which were used as filters to collect solid catalytic particles from an organic solution of disodium iminodiacetate, was investigated. The initial microstructure of the sintered filter is composed of twinned Ni-? grains and pores, but during use severe embrittlement of the cartridges was accompanied by an intense loss of material, leading to an

C. R. F. Azevedo; D. Rodrigues; J. V. Ferrari

2007-01-01

389

Simulation of Sintering of Layered Structures.  

National Technical Information Service (NTIS)

An integrated approach, combining the continuum theory of sintering and Potts model based mesostructure evolution analysis, is used to solve the problem of bi-layered structure sintering. Two types of bi-layered structures are considered: layers of the sa...

Olevsky Tikare Garino Braginsky

2000-01-01

390

Method of sintering materials with microwave radiation  

DOEpatents

Disclosed is a method of sintering ceramic materials. A compacted article comprising inorganic particles coated with carbon is provided, the carbon providing improved microwave coupling. The compacted article is then heated by microwave radiation to a temperature and for a period of time sufficient to sinter the compacted article. No Drawings

Kimrey, H.D. Jr.; Holcombe, C.E. Jr.; Dykes, N.L.

1994-06-14

391

Effect of Process Parameter on Barium Titanate Stannate (BTS) Materials Sintered at Low Sintering  

NASA Astrophysics Data System (ADS)

Ba(Ti1-xSnx)O3 solid solutions with (x = 0.15, 0.20, 0.30 and 0.40) are synthesized using conventional solid state reaction method. Formation of solid solutions in the range 0 <= x <=0.40 is confirmed using X-ray diffraction technique. Single phase solid solutions with homogeneous grain distribution are observed at relatively low sintering by controlling process parameters viz. sintering time. Composition at optimized temperature (1150 C) sintered by varying the sintering time, stabilize in cubic perovskite phase. The % experimental density increase with increasing the time of sintering instead of increasing sintering temperature. The lattice parameter increases by increasing the tin composition in the material. This demonstrates that process parameter optimization can lead to single phase at relatively lower sintering-a major advantage for the materials used as capacitor element in MLCC.

Shukla, Alok; Bajpai, P. K.

2011-11-01

392

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

393

Liquid phase sintered superconducting cermet  

SciTech Connect

This patent describes a method of making a superconducting cermet having superconducting properties with improved bulk density, low porosity and in situ stabilization. It comprises: forming a structure of a superconducting ceramic material having the formula RM{sub 2}Cu{sub 3}O{sub (6.5 + x)}wherein R is one or more rare earth elements capable of reacting to form a superconducting ceramic, M is one or more alkaline earth metal elements selected from barium and strontium capable of reacting to form a superconducting ceramic, x is greater than 0 and less than 0.5; and a precious metal compound in solid form selected from the class consisting of oxides, sulfides and halides of silver; and liquid phase sintering the mixture at a temperature wherein the precious metal of the precious metal compound is molten and below the melting point of the ceramic material. The liquid phase sintering is carried out for a time less than 36 hours but sufficient to improve the bulk density of the cermet.

Ray, S.P.

1990-01-09

394

Simulation of Sintering of Layered Structures  

SciTech Connect

An integrated approach, combining the continuum theory of sintering and Potts model based mesostructure evolution analysis, is used to solve the problem of bi-layered structure sintering. Two types of bi-layered structures are considered: layers of the same material with different initial porosity, and layers of two different materials. The effective sintering stress for the bi-layer powder sintering is derived, both at the meso- and the macroscopic levels. Macroscopic shape distortions and spatial distributions of porosity are determined as functions of the dimensionless specific time of sintering. The effect of the thickness of the layers on shrinkage, warpage, and pore-grain structure is studied. Ceramic ZnO powders are employed as a model experimental system to assess the model predictions.

OLEVSKY,EUGENE; TIKARE,VEENA; GARINO,TERRY J.; BRAGINSKY,MICHAEL V.

2000-11-22

395

A circulation mud system used in long-distance ore pipeline transportation  

NASA Astrophysics Data System (ADS)

The long-distance ore pipeline transportation is a new and high-tech industry, which is non-polluting, zero emissions, and in line with the strategy needs of national low-carbon economy and energy demand reduction. The long-distance ore transport needs multi-station pumping station transportation, however, the low concentration slurry that does not match the technological requirements, such as slurry head and so on. This paper designs a circulation mud system used in long-distance pipeline transportation, which solves the following issues: (1) the technical pool can't storage water during the period of cleaning mine, so can't meet the needs of non-suspension production; (2) slurry spot cool dry easy to bring serious environmental pollution; (3) the refined iron dug out from the process pool need transport to iron and steel industry, trucking transportation needs a huge costs. Experience has shown that the system effectively improve the production efficiency and propagate.

Li, Youling; Wang, Hua

2011-10-01

396

Iron Mountain Electromagnetic Results  

SciTech Connect

Iron Mountain Mine is located seventeen miles northwest of Redding, CA. After the completion of mining in early 1960s, the mine workings have been exposed to environmental elements which have resulted in degradation in water quality in the surrounding water sheds. In 1985, the EPA plugged ore stoops in many of the accessible mine drifts in an attempt to restrict water flow through the mine workings. During this process little data was gathered on the orientation of the stoops and construction of the plugs. During the last 25 years, plugs have begun to deteriorate and allow acidic waters from the upper workings to flow out of the mine. A team from Idaho National Laboratory (INL) performed geophysical surveys on a single mine drift and 3 concrete plugs. The project goal was to evaluate several geophysical methods to determine competence of the concrete plugs and orientation of the stopes.

Gail Heath

2012-07-01

397

Recent trends in iron and steelmaking technology  

Microsoft Academic Search

Iron and steelmaking technology, including the preparation of raw materials and utilisation of wastes, has undergone marked\\u000a changes over the last five decades. The hand mining of ores\\/minerals has almost completely been replaced by mechanised mining.\\u000a The role of mineral beneficiation and sizing has therefore increased. The current emphasis is on maximising the use of mined\\u000a materials through multiple beneficiation

B N Singh

1989-01-01

398

The fluid regime of ore formation in the Balei gold-bearing ore-magmatic system ( eastern Transbaikalia, Russia)  

Microsoft Academic Search

Based on comprehensive studies of fluid inclusions in quartz formed at different stages of hydrothermal process, we consider the physicochemical conditions of formation of epithermal ores (K1) in the Balei ore field. The limiting parameters of hydrothermal process have been established: 353131 C, 15030 bars, and salt concentrations of 7.60.5 wt.%-NaCl equiv. A specific feature of the ore-forming process at

A. M. Spiridonov; L. D. Zorina; S. P. Letunov; V. Yu. Prokofev

2010-01-01

399

Iron sponge: still a top option for sour gas sweetening  

SciTech Connect

Engineering, research, and field data have been updated to present a detailed evaluation of gas sweetening via the iron sponge process. The iron sponge process is one of the oldest known methods for the removal of hydrogen sulfide and sulfur compounds from gas streams. The technique originated in Europe over 100 years ago and is still widely used today for gas sweetening. The process entails passing sour gas (i.e., a gas stream containing hydrogen sulfide and/or mercaptans) across a bed of hydrated iron oxide. The subsequent reaction with hydrogen sulfide produces iron sulfides and a small amount of byproduct water. The earliest operators actually employed a naturally occurring form of the hydrated iron oxide, referred to as bog iron or bog ore, but which is more correctly known as limonite (i.e., hydrous iron oxides that mineralogically are composed of various mixtures of goethite and/or legidocrocite).

Anerousis, J.P.; Whitman, S.K.

1985-02-18

400

40 CFR 440.60 - Applicability; description of the tungsten ore subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the tungsten ore subcategory. 440.60 Section 440.60...CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Tungsten Ore Subcategory § 440.60...

2011-07-01

401

40 CFR 440.90 - Applicability; description of the antimony ore subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the antimony ore subcategory. 440.90 Section 440.90...CONTINUED) EFFLUENT GUIDELINES AND STANDARDS ORE MINING AND DRESSING POINT SOURCE CATEGORY Antimony Ore Subcategory § 440.90...

2011-07-01

402

40 CFR 440.80 - Applicability; description of the vanadium ore subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the vanadium ore subcategory. 440.80 Section 440.80...EFFLUENT GUIDELINES AND STANDARDS (CONTINUED) ORE MINING AND DRESSING POINT SOURCE CATEGORY Vanadium Ore Subcategory (Mined Alone and Not as a...

2012-07-01

403

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

Code of Federal Regulations, 2013 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2013-07-01

404

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the platinum ore subcategory. 440.110 Section...AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The...

2010-07-01

405

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.  

Code of Federal Regulations, 2010 CFR

...Applicability; description of the platinum ore subcategory. 440.110 Section...AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The...

2009-01-01

406

40 CFR 440.110 - Applicability; description of the platinum ore subcategory.  

Code of Federal Regulations, 2011 CFR

...Applicability; description of the platinum ore subcategory. 440.110 Section...AND DRESSING POINT SOURCE CATEGORY Platinum Ores Subcategory § 440.110 Applicability; description of the platinum ore subcategory. The...

2011-07-01

407

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

2010-07-01

408

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

2009-01-01

409

40 CFR 440.70 - Applicability; description of the nickel ore subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the nickel ore subcategory. 440.70 Section...MINING AND DRESSING POINT SOURCE CATEGORY Nickel Ore Subcategory § 440.70 Applicability; description of the nickel ore subcategory. The...

2011-07-01

410

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.  

Code of Federal Regulations, 2013 CFR

... Applicability; description of the mercury ore subcategory. 440.40 Section...AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The...

2013-07-01

411

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.  

Code of Federal Regulations, 2010 CFR

... Applicability; description of the mercury ore subcategory. 440.40 Section...AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The...

2009-01-01

412

40 CFR 440.40 - Applicability; description of the mercury ore subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the mercury ore subcategory. 440.40 Section...AND DRESSING POINT SOURCE CATEGORY Mercury Ore Subcategory § 440.40 Applicability; description of the mercury ore subcategory. The...

2011-07-01

413

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.  

Code of Federal Regulations, 2012 CFR

... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

2013-07-01

414

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

Code of Federal Regulations, 2010 CFR

...true Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2009-01-01

415

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

Code of Federal Regulations, 2010 CFR

...false Applicability; description of the uranium, radium and vanadium ores subcategory...MINING AND DRESSING POINT SOURCE CATEGORY Uranium, Radium and Vanadium Ores Subcategory...30 Applicability; description of the uranium, radium and vanadium ores...

2010-07-01

416

40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.  

Code of Federal Regulations, 2011 CFR

... Applicability; description of the aluminum ore subcategory. 440.20 Section...AND DRESSING POINT SOURCE CATEGORY Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The...

2011-07-01

417

28 CFR 79.63 - Proof of employment as an ore transporter.  

Code of Federal Regulations, 2010 CFR

...false Proof of employment as an ore transporter. 79.63 Section 79.63 Judicial...Eligibility Criteria for Claims by Ore Transporters § 79.63 Proof of employment as an ore transporter. (a) The Department will...

2009-07-01

418

Gold ore-forming fluids of the Tanami region, Northern Australia  

NASA Astrophysics Data System (ADS)

Fluid inclusion studies have been carried out on major gold deposits and prospects in the Tanami region to determine the compositions of the associated fluids and the processes responsible for gold mineralization. Pre-ore, milky quartz veins contain only two-phase aqueous inclusions with salinities ?19 wt% NaCl eq. and homogenization temperatures that range from 110 to 410C. In contrast, the ore-bearing veins typically contain low to moderate salinity (<14 wt% NaCl eq.), H2O + CO2 CH4 N2-bearing fluids. The CO2-bearing inclusions coexist with two-phase aqueous inclusions that exhibit a wider range of salinities (?21 wt% NaCl eq.). Post-ore quartz and carbonate veins contain mainly two-phase aqueous inclusions, with a last generation of aqueous inclusions being very CaCl2-rich. Salinities range from 7 to 33 wt% NaCl eq. and homogenization temperatures vary from 62 to 312C. Gold deposits in the Tanami region are hosted by carbonaceous or iron-rich sedimentary rocks and/or mafic rocks. They formed over a range of depths at temperatures from 200 to 430C. The Groundrush deposit formed at the greatest temperatures and depths (260-430C and ?11 km), whereas deposits in the Tanami goldfield formed at the lowest temperatures (?200C) and at the shallowest depths (1.5-5.6 km). There is also evidence in the Tanami goldfield for late-stage isothermal mixing with higher salinity (?21 wt% NaCl eq.) fluids at temperatures between 100 and 200C. Other deposits (e.g., The Granites, Callie, and Coyote) formed at intermediate depths and at temperatures ranging from 240 to 360C. All ore fluids contained CO2 N2 CH4, with the more deeply formed deposits being enriched in CH4 and higher level deposits being enriched in CO2. Fluids from deposits hosted mainly by sedimentary rocks generally contained appreciable quantities of N2. The one exception is the Tanami goldfield, where the quartz veins were dominated by aqueous inclusions with rare CO2-bearing inclusions. Calculated ? 18O values for the ore fluids range from 3.8 to 8.5 and the corresponding ?D values range from -89 to -37. Measured ? 13C values from CO2 extracted from fluid inclusions ranged from -5.1 to -8.4. These data indicate a magmatic or mixed magmatic/metamorphic source for the ore fluids in the Tanami region. Interpretation of the fluid inclusion, alteration, and structural data suggests that mineralization may have occurred via a number of processes. Gold occurs in veins associated with brittle fracturing and other dilational structures, but in the larger deposits, there is also an association with iron-rich rocks or carbonaceous sediments, suggesting that both structural and chemical controls are important. The major mineralization process appears to be boiling/effervescence of a gas-rich fluid, which leads to partitioning of H2S into the vapor phase resulting in gold precipitation. However, some deposits also show evidence of desulfidation by fluid-rock interaction and/or reduction of the ore-fluid by fluid mixing. These latter processes are generally more prevalent in the higher crustal-level deposits.

Mernagh, Terrence P.; Wygralak, Andrew S.

2007-01-01

419

Iron Aluminide Composites  

SciTech Connect

Iron aluminides with the B2 structure are highly oxidation and corrosion resistant. They are thermodynamically compatible with a wide range of ceramics such as TiC, WC, TiB{sub 2}, and ZrB{sub 2}. In addition, liquid iron aluminides wet these ceramics very well. Therefore, FeAl/ceramic composites may be produced by techniques such as liquid phase sintering of powder mixtures, or pressureless melt infiltration of ceramic powders with liquid FeAl. These techniques, the resulting microstructure, and their advantages as well as limitations are described. Iron aluminide composites can be very strong. Room temperature flexure strengths as high as 1.8 GPa have been observed for FeAl/WC. Substantial gains in strength at elevated temperatures (1073 K) have also been demonstrated. Above 40 vol.% WC the room temperature flexure strength becomes flaw-limited. This is thought to be due to processing flaws and limited interfacial strength. The fracture toughness of FeAl/WC is unexpectedly high and follows a mile of mixtures. Interestingly, sufficiently thin (< 1 {micro}m) FeAl ligaments between adjacent WC particles fracture not by cleavage, but in a ductile manner. For these thin ligaments the dislocation pile-ups formed during deformation are not long enough to nucleate cleavage fracture, and their fracture mode is therefore ductile. For several reasons, this brittle-to-ductile size transition does not improve the fracture toughness of the composites significantly. However, since no cleavage cracks are nucleated in sufficiently thin FeAl ligaments, slow crack growth due to ambient water vapor does not occur. Therefore, as compared to monolithic iron aluminizes, environmental embrittlement is dramatically reduced in iron aluminide composites.

Schneibel, J.H.

1998-11-20

420

Total Ore Processing Integration and Management  

SciTech Connect

This report outlines the technical progress achieved for project DE-FC26-03NT41785 (Total Ore Processing Integration and Management) during the period 01 October through 31 December of 2005. Graphical analysis of blast patterns according to drill monitor data is continuing. Multiple linear regression analysis of 16 mine and mill variables (powder factor, two modeled size fractions, liberation index, predicted grind, total crude Fe, Satmagan Fe, sat ratio, DSC, geologic blend, ambient temperature, cobbing hours, feeder plugs, and percent feeder run time-of-mill time) indicates that December variations in plant performance are generally predictable (Figure 1). The outlier on December 28th coincides with low cobbing availability and equipment downtime. Mill productivity appeared to be most influenced, as usual, by ore quality as indicated by the liberation index--the higher the liberation index, the lower the throughput. The upcoming quarter will be concerned with wrapping up the work in progress, such as the detailed statistical analyses, and writing a final report. Hibtac Mine engineers are evaluating neural network software to determine its utility for modeling, and eventually predicting, mill throughput.

Leslie Gertsch

2006-01-30

421

Microbiological and geochemical dynamics in simulated-heap leaching of a polymetallic sulfide ore.  

PubMed

The evolution of microbial populations involved in simulated-heap leaching of a polymetallic black schist sulfide ore (from the recently-commissioned Talvivaara mine, Finland) was monitored in aerated packed bed column reactors over a period of 40 weeks. The influence of ore particle size (2-6.5 mm and 6.5-12 mm) on changes in composition of the bioleaching microflora and mineral leaching dynamics in columns was investigated and compared to fine-grain (<2 microm) ore that was bioprocessed in shake flask cultures. Both column reactors and shake flasks were inoculated with 24 different species and strains of mineral-oxidizing and other acidophilic micro-organisms, and maintained at 37 degrees C. Mineral oxidation was most rapid in shake flask cultures, with about 80% of both manganese and nickel and 68% of zinc being leached within 6 weeks, though relatively little of the copper present in the ore was solubilised. The microbial consortium that emerged from the original inoculum was relatively simple in shake flasks, and was dominated by the iron-oxidizing autotroph Leptospirillum ferriphilum, with smaller numbers of Acidimicrobium ferrooxidans, Acidithiobacillus caldus and Leptospirillum ferrooxidans. Both metal recovery and (for the most part) total numbers of prokaryotes were greater in the column reactor containing the medium-grain than that containing the coarse-grain ore. The bioleaching communities in the columns displayed temporal changes in composition and differed radically from those in shake flask cultures. While iron-oxidizing chemoautotrophic bacteria were always the most numerically dominant bacteria in the medium-grain column bioreactor, there were major shifts in the most abundant species present, with the type strain of Acidithiobacillus ferrooxidans dominating in the early phase of the experiment and other bacteria (At. ferrooxidans NO37 and L. ferriphilum) dominating from week 4 to week 40. With the coarse-grain column bioreactor, similar transitions in populations of iron-oxidizing chemoautotrophs were observed, though heterotrophic acidophiles were often the most abundant bacteria found in mineral leach liquors. Four bacteria not included in the mixed culture used to inoculate the columns were detected by biomolecular techniques and three of these (all Alicyclobacillus-like Firmicutes) were isolated as pure cultures. The fourth bacterium, identified from a clone library, was related to the Gram-positive sulfate reducer Desulfotomaculum salinum. All four were considered to have been present as endospores on the dried ore, which was not sterilized in the column bioreactors. Two of the Alicyclobacillus-like isolates were found, transiently, in large numbers in mineral leachates. The data support the hypothesis that temporal and spatial heterogeneity in mineral heaps create conditions that favour different mineral-oxidizing microflora, and that it is therefore important that sufficient microbial diversity is present in heaps to optimize metal extraction. PMID:18496880

Wakeman, Kathryn; Auvinen, Hannele; Johnson, D Barrie

2008-11-01

422

Enery Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications  

SciTech Connect

This is the final technical report for the Department of Energy NETL project NT01931 Energy Efficient Press and Sinter of Titanium Powder for Low-Cost Components in Vehicle Applications. Titanium has been identified as one of the key materials with the required strength that can reduce the weight of automotive components and thereby reduce fuel consumption. Working with newly developed sources of titanium powder, Webster-Hoff will develop the processing technology to manufacture low cost vehicle components using the single press/single sinter techniques developed for iron based powder metallurgy today. Working with an automotive or truck manufacturer, Webster-Hoff will demonstrate the feasibility of manufacturing a press and sinter titanium component for a vehicle application. The project objective is two-fold, to develop the technology for manufacturing press and sinter titanium components, and to demonstrate the feasibility of producing a titanium component for a vehicle application. The lowest cost method for converting metal powder into a net shape part is the Powder Metallurgy Press and Sinter Process. The method involves compaction of the metal powder in a tool (usually a die and punches, upper and lower) at a high pressure (up to 60 TSI or 827 MPa) to form a green compact with the net shape of the final component. The powder in the green compact is held together by the compression bonds between the powder particles. The sinter process then converts the green compact to a metallurgically bonded net shape part through the process of solid state diffusion. The goal of this project is to expand the understanding and application of press and sinter technology to Titanium Powder applications, developing techniques to manufacture net shape Titanium components via the press and sinter process. In addition, working with a vehicle manufacturer, demonstrate the feasibility of producing a titanium component for a vehicle. This is not a research program, but rather a project to develop a process for press and sinter of net shape Titanium components. All of these project objectives have been successfully completed.

Thomas Zwitter; Phillip Nash; Xiaoyan Xu; Chadwick Johnson

2011-03-31

423

40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...  

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

40. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-39) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

424

39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also ...  

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

39. HULETT ORE UNLOADER IN MOTION. VIEW LOOKING EAST. (Also see OH-18-14, OH-18-38, and OH-18-40) - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

425

24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT ...  

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

24. REAR ELEVATION, HULETT ORE UNLOADERS. TRACKS CARRYING THE FRONT END AND REAR LEGS OF THE HULETT UNLOADERS ARE LAID ON THE DOCK AND REAR WALLS, RESPECTIVELY; BOTH WALLS ARE MADE OF REINFORCED CONCRETE SUPPORTED ON CONCRETE PILES. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

426

LOOKING WEST ALONG PASSAGE BETWEEN CRUSHING ROOM AND FINE ORE ...  

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

LOOKING WEST ALONG PASSAGE BETWEEN CRUSHING ROOM AND FINE ORE BIN AREA. NOTE STEEL CUSTOM ORE CHUTES IN BACKGROUND. THE FARTHEST BINS WERE LAST USED FOR STORAGE OF BALL MILL BALLS. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

427

14. OBLIQUE VIEW OF UPPER ORE BIN AND LOADING DECK, ...  

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

14. OBLIQUE VIEW OF UPPER ORE BIN AND LOADING DECK, LOOKING WEST. DETAIL OF SUPPORTING TIMBERS. THE LOCATION OF THIS ORE BIN IN RELATION TO THE MILL CAN BE SEEN IN MANY OF THE MILL OVERVIEWS. (CA-290-4 THROUGH CA-290-8). - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

428

TRAM HOUSE INTERIOR, LOOKING SOUTHEAST. NOTE DEPARTING ORE BUCKET "12" ...  

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

TRAM HOUSE INTERIOR, LOOKING SOUTHEAST. NOTE DEPARTING ORE BUCKET "12" AND SUSPENSION CABLE ANGLING DOWN THROUGH FLOOR AT LOWER LEFT. LARGE LEVER ON SIDE OF BUCKET ALLOWS IT TO BE ROTATED FOR DUMPING ORE. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

429

DETAIL OVERHEAD VIEW OF SECONDARY ORE BIN, CONVEYOR PLATFORM TRAM ...  

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

DETAIL OVERHEAD VIEW OF SECONDARY ORE BIN, CONVEYOR PLATFORM TRAM TRESTLE, AND LOADING PLATFORM, LOOKING SOUTHWEST. THE HOLE IN THE ORE BIN FLOOR CAN BE SEEN, AND BALL MILL FOUNDATION AT LOWER LEFT CORNER. SEE CA-291-13 FOR IDENTICAL B&W NEGATIVE. - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

430

15. NORTH ELEVATION OF UPPER ORE BIN, CHUTE, AND JAW ...  

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

15. NORTH ELEVATION OF UPPER ORE BIN, CHUTE, AND JAW CRUSHER, LOOKING SOUTH FROM END OF CONVEYOR PLATFORM. NOTICE THE THREE ORE BIN CONTROL DOORS, CORRESPONDING TO SEPARATE COMPARTMENTS OF THE BIN. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

431

25. DETAIL OF STRUCTURAL TIMBERS, ORE BIN, AND STAIRWAY TO ...  

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

25. DETAIL OF STRUCTURAL TIMBERS, ORE BIN, AND STAIRWAY TO TOP FLOOR OF MILL, LOOKING SOUTH FROM SECOND FLOOR OF MILL. PORTION OF ORE BIN ON RIGHT, STAIRS ON LEFT. - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

432

25. INTERIOR VIEW LOOKING SOUTH IN THE ORE RECEIVING LEVEL ...  

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

25. INTERIOR VIEW LOOKING SOUTH IN THE ORE RECEIVING LEVEL SHOWING THE TRAMWAY TRACKS IN THE FLOOR, ORE CHUTES IN THE FLOOR, NEWER TRACKS COMING IN FROM THE TRESTLE ON THE EAST SIDE OF THE MILL., AND THE WINDING DRUM THE TRAMWAY IN THE BACKGROUND. - Standard Gold Mill, East of Bodie Creek, Northeast of Bodie, Bodie, Mono County, CA

433

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. ...  

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

13. OBLIQUE VIEW OF UPPER ORE BIN, LOOKING WEST NORTHWEST. THIS ORE BIN WAS ADDED IN THE LATE 1930'S. IT IS TRAPAZOIDAL IN SHAPE, WIDER AT THE REAR THAN THE FRONT, AND DIVIDED INTO THREE BINS, EACH WITH ITS OWN CONTROL DOOR (SEE CA-290-15). - Skidoo Mine, Park Route 38 (Skidoo Road), Death Valley Junction, Inyo County, CA

434

Calculation of O-ring failure due to material aging.  

National Technical Information Service (NTIS)

Applications where O-rings are used to isolate atmospheric environments within a structure are critical to weapon reliability. Failure occurs when gases are able to travel from one side of the O-ring to the other. The anticipated cause of failure is the r...

D. Segalman L. Weingarten R. Chambers

1997-01-01

435

Ore Separation in a Packed-Fluidized Bed.  

National Technical Information Service (NTIS)

The segregating tendency of particles of differing densities in a gas-fluidized packed bed was applied to ore separation. Two columns (5- and 3-cm. i.d.) filled with cylindrical screen packing were used to study the upgrading of a germanium ore and two ir...

C. E. Capes J. P. Sutherland

1965-01-01

436

Laboratory Studies of Ammonia Leaching of Copper Ores. Volume I.  

National Technical Information Service (NTIS)

This report describes the results of ammonia leaching studies on sulfide and native copper ores of Michigan. Tests were performed on pure minerals to determine the kinetics of leaching and on ore samples to determine leaching rates, reagent losses, and di...

W. A. Hockings W. L. Freyberger

1975-01-01

437

19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ...  

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

19. VIEW OF CRUDE ORE BINS FROM EAST. EAST CRUDE ORE BIN IN FOREGROUND WITH DISCHARGE TO GRIZZLY AT BOTTOM OF VIEW. CONCRETE RETAINING WALL TO LEFT (SOUTH) AND BOTTOM (EAST EDGE OF EAST BIN). - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

438

27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW ...  

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

27. HULETT ORE UNLOADERS TEMPORARILY IN REPOSE, AS A NEW SKIP TIES UP AT DOCK. THE UNLOADERS OPERATE ALMOST CONTINUOUSLY DURING THE SHIPPING SEASON, WHICH USUALLY RUNS FROM APRIL UNTIL LATE DECEMBER OR EARLY JANUARY. VIEW HERE IS LOOKING NORTHEAST. - Pennsylvania Railway Ore Dock, Lake Erie at Whiskey Island, approximately 1.5 miles west of Public Square, Cleveland, Cuyahoga County, OH

439

PROCESS FOR THE CONCENTRATION OF ORES CONTAINING GOLD AND URANIUM  

DOEpatents

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.

Gaudin, A.M.; Dasher, J.

1958-06-10

440

Novel Binders and Methods for Agglomeration of Ore  

Microsoft Academic Search

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

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

2006-01-01

441

Method of Winning Aluminum Metal from Aluminous Ore.  

National Technical Information Service (NTIS)

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 wit...

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

1979-01-01

442

Helium and Deuterium Permeability in O-Rings.  

National Technical Information Service (NTIS)

To obtain more information on gas permeation through elastomeric O-rings, studies were performed on Parker Seal Company O-rings, Nos. 2-113, 2-006, 3-904, and 3-906, all made of a nitrile rubber. Also included in the tests was a valve packing (Autoclave E...

J. F. Lakner

1976-01-01

443

64. NORTH WALL OF CRUSHED OXIDIZED ORE BIN. THE PRIMARY ...  

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

64. NORTH WALL OF CRUSHED OXIDIZED ORE BIN. THE PRIMARY MILL FEEDS AT BOTTOM. MILL SOLUTION TANKS WERE TO THE LEFT (EAST) AND BARREN SOLUTION TANK TO THE RIGHT (WEST) OR THE CRUSHED ORE BIN. - Bald Mountain Gold Mill, Nevada Gulch at head of False Bottom Creek, Lead, Lawrence County, SD

444

Prolonged history of episodic fluid flow in giant hematite ore bodies: Evidence from in situ U Pb geochronology of hydrothermal xenotime  

NASA Astrophysics Data System (ADS)

Absolute ages for hydrothermal mineralization and fluid flow are critical for understanding the geological processes that concentrate metals in the Earth's crust, yet many ore deposits remain undated because suitable mineral chronometers have not been found. The origin of giant hematite ore deposits, which are hosted in Precambrian banded-iron formations (BIFs), remains contentious. Several models have been formulated based on different sources and timing for the mineralizing fluids; supergene-metamorphic, syn-orogenic, late-orogenic extensional collapse and syn-extensional. Precise geochronology of the ore offers a means of discriminating between these models. In this study, two U Pb chronometers, xenotime and monazite, have been identified in high-grade hematite ore bodies from the Mount Tom Price mine in the Hamersley Province, northwestern Australia. Both phosphate minerals occur as inclusions within the hematite ore and as coarser crystals intergrown with martite (hematite pseudomorph after magnetite) and microplaty hematite, indicating that the xenotime and monazite precipitated during mineralization. In situ U Pb dating by ion microprobe indicates that both phosphate minerals grew during multiple discrete events. Our results suggest that ore genesis may have commenced as early as 2.15 Ga, with subsequent hydrothermal remobilization and/or mineralization at 2.05 Ga, 1.84 Ga, 1.67 Ga, 1.59 Ga, 1.54 Ga, 1.48 Ga and 0.85 Ga. The location of the ore bodies along ancient fault systems, and the coincidence of at least some of the U Pb phosphate dates with episodes of tectonothermal activity in the adjacent Proterozoic Capricorn Orogen, implies that fluids were channelled through major structures in the southern Pilbara Craton during discrete phases of tectonic compression and extension. Our results show that the hematite ore bodies formed at sites of repeated focussed hydrothermal fluid flow. In contrast to the aforementioned models, our results imply that iron-ore formation was probably a long-lived, multi-stage process spanning more than one billion years.

Rasmussen, Birger; Fletcher, Ian R.; Muhling, Janet R.; Thorne, Warren S.; Broadbent, Graeme C.

2007-06-01

445

The effect of sintering temperatures on alumina foam strength  

Microsoft Academic Search

An idea to improve the strength of ceramic foams by controlling the sintering temperature was proposed in this paper. The effect of sintering temperatures on alumina foams strength was investigated by discussing three factors: shrinkage, porosity and grain size, which changed with sintering temperatures. When the sintering temperature increased from 1400 to 1500C, the samples shrunk increasingly and the porosity

Yong-sheng Han; Jian-bao Li; Qiang-min Wei; Ke Tang

2002-01-01

446

Sintering of sponge and hydride-dehydride titanium powders  

Microsoft Academic Search

The sintering behavior of compacts produced from sponge and hydride-dehydride (HDH) Ti powders was examined. Compacts were vacuum sintered at 1200 or 1300 deg C for 30, 60, 120, 240, 480 or 960 minutes. The porosity decreased with sintering time and\\/or temperature in compacts produced from the HDH powders. Compacts produced from these powders could be sintered to essentially full

David E. Alman; Stephen J. Gerdemann

2004-01-01

447

Room Temperature Aging Study of Butyl O-rings  

SciTech Connect

During testing under the Enhanced Surveillance Campaign in 2001, preliminary data detected a previously unknown and potentially serious concern with recently procured butyl o-rings. All butyl o-rings molded from a proprietary formulation throughout the period circa 1999 through 2001 had less than a full cure. Tests showed that sealing force values for these suspect o-rings were much lower than expected and their physical properties were very sensitive to further post curing at elevated temperatures. Further testing confirmed that these o-rings were approximately 50% cured versus the typical industry standard of > 90% cured. Despite this condition, all suspect o-rings fully conformed to their QC acceptance requirements, including their individual product drawing requirements.

Mark Wilson

2009-08-07

448

Oxide Transformation in Cr-Mn-Prealloyed Sintered Steels: Thermodynamic and Kinetic Aspects  

NASA Astrophysics Data System (ADS)

The main obstacle for utilization of Cr and Mn as alloying elements in powder metallurgy is their high oxygen affinity leading to oxidation risk during powder manufacturing, handling, and especially during further consolidation. Despite the high purity of the commercially available Cr- and Mn-prealloyed iron powder grades, the risk of stable oxide formation during the sintering process remains. Thermodynamic and kinetic simulation of the oxide formation/transformation on the former powder surface during heating and sintering stages using thermodynamic modeling tools (Thermo-Calc and HSC Chemistry) was performed. Simulation is based on the results from the analysis of amount, morphology, and composition of the oxide phases inside the inter-particle necks in the specimens from interrupted sintering trials utilizing advanced analysis tools (HRSEM + EDX and XPS). The effect of the processing parameters, such as sintering atmosphere composition, temperature profile as well as graphite addition on the possible scenarios of oxide reduction/formation/transformation for Fe-Cr-Mn-C powder systems, was evaluated. Results indicate that oxide transformation occurs in accordance with the thermodynamic stability of oxides as follows: Fe2O3 ? FeO ? Fe2MnO4 ? Cr2FeO4 ? Cr2O3 ? MnCr2O4 ? MnO/MnSiO x ? SiO2. Spinel MnCr2O4 was identified as the most stable oxide phase at applied sintering conditions up to 1393 K (1120 C). Controlled conditions during the heating stage minimize the formation of stable oxide products and produce oxide-free sintered parts.

Hryha, Eduard; Nyborg, Lars

2013-09-01

449

Sintering of sponge and hydride-dehydride titanium powders  

SciTech Connect

The sintering behavior of compacts produced from sponge and hydride-dehydride (HDH) Ti powders was examined. Compacts were vacuum sintered at 1200 or 1300 deg C for 30, 60, 120, 240, 480 or 960 minutes. The porosity decreased with sintering time and/or temperature in compacts produced from the HDH powders. Compacts produced from these powders could be sintered to essentially full density. However, the sintering condition did not influence the amount of porosity present in compacts produced from the sponge powders. These samples could only be sintered to a density of 97% theoretical. The sintering behavior was attributed to the chemical impurities in the powders.

Alman, David E.; Gerdemann, Stephen J.

2004-04-01

450

Densification of Alumina Ceramics Sintered by Using Submillimeter Wave Gyrotron  

NASA Astrophysics Data System (ADS)

The sintering of high purity alumina, by using a very high frequency in range sub-millimeter waves, is presented in this paper. The sintering was performed by using a 300 GHz material processing system. Achieving homogeneous and volumetric heating on submillimeter wave sintering was confirmed by the grain size distribution analysis. The densification curves were obtained for submillimeter wave (300 GHz), millimeter wave (28 GHz), and conventional processing. The enhancement of densification and early shrinkage were observed on submillimeter wave sintering. However, compared with millimeter wave method, the densification of sub-millimeter wave sintering is lower at all sintering temperatures. The grain coarsening was analyzed using SEM photographs of fracture surfaces. The grain sizes of submillimeter wave sintered samples were smaller than those of the millimeter wave sintered samples. The effect of cold isostatic pressing, was also evaluated on submillimeter wave sintering. It suggests that the cold isostatic pressing method is quite effective for densification of SMMW sintering alumina.

Sudiana, I. N.; Ito, R.; Inagaki, S.; Kuwayama, K.; Sako, K.; Mitsudo, S.

2013-10-01

451

Effect of chemical composition and sintering conditions on the mechanical properties of sintered duplex stainless steels  

Microsoft Academic Search

Duplex stainless steels were obtained through powder metallurgy technology from austenitic AISI 316L and ferritic AISI 430L powders mixed in different amounts to obtain ratios of austenite\\/ferrite of 25\\/75, 50\\/50 and 75\\/25. Prepared powder mixes were compacted at 650 or 750MPa and sintered in N2H2 atmosphere (95%-5%) at several sintering conditions and with three sintering cooling rates (furnace, gas and

F. Martn; C. Garca; Y. Blanco

2011-01-01

452

Treatability of chromite ore processing waste by leaching.  

PubMed

Developing treatment and disposal strategies and health-based clean-up standards for chromium containing wastes continues to be an important environmental regulatory issue because of the opposing solubility and toxicity characteristics of chromium species under diverse environmental conditions. In this study, leaching characteristics of total Cr and Cr(VI) were investigated using laboratory column studies. The data obtained from the experimental studies were analysed to assess the treatability of chromite ore processing waste (COPW) by leaching and to identify the leaching strategies that enhance mass removal rates of chromium species. COPW used for laboratory soil column studies was obtained from an industrial plant producing sodium chromate in Mersin, Turkey. Laboratory investigations involved chemical characterisation of waste material and column studies. For waste characterisation, U.S. EPA toxicity characterisation leaching procedure (TCLP) was performed on COPW to determine the concentrations of metal species in the TCLP extract. For column studies, various laboratory columns containing plain COPW material, 1:1 COPW/reducing agent (elemental iron or manure) mixture and different type soils (sand, loam and clay) overlain by COPW were subjected to leaching tests using acidic, neutral and alkaline influent water to determine Cr mass leaching efficiencies. Based on the TCLP analyses, COPW is classified as hazardous waste. As a result of comparing the leaching efficiency data from twelve leaching columns, the maximum removal of total Cr was achieved by leaching COPW/manure mixture using acidic (pH 4.78) influent water. The highest Cr(VI) leaching efficiency was achieved in the columns of plain COPW and COPW/manure mixture using highly alkaline (pH 12.0) influent water. The least effective leaching efficiency for both total Cr and Cr (VI) was obtained by leaching plain COPW with neutral (pH 7.0) influent water. Land-disposal of the treated COPW material by mixing with clayey soils seems to be a viable alternative. PMID:11699856

Unl, K; Haskk, S

2001-06-01

453

Iron and zinc partitioning between coexisting stannite and sphalerite: a possible indicator of temperature and sulfur fugacity  

Microsoft Academic Search

Stannite and sphalerite coexisting with iron sulfides (pyrite and\\/or pyrrhotite) from Japanese ore deposits associated with tin mineralization were analyzed. Based on the iron and zinc partitioning between stannite and sphalerite, the formation temperature and sulfur fugacity for this mineral assemblage were estimated. A good correlation between stannite-sphalerite temperatures and filling temperatures of fluid inclusions and sulfur isotope temperatures was

M. Shimizu; N. Shikazono

1985-01-01

454

Sintered electrode for solid oxide fuel cells  

DOEpatents

A solid oxide fuel cell fuel electrode is produced by a sintering process. An underlayer is applied to the electrolyte of a solid oxide fuel cell in the form of a slurry, which is then dried. An overlayer is applied to the underlayer and then dried. The dried underlayer and overlayer are then sintered to form a fuel electrode. Both the underlayer and the overlayer comprise a combination of electrode metal such as nickel, and stabilized zirconia such as yttria-stabilized zirconia, with the overlayer comprising a greater percentage of electrode metal. The use of more stabilized zirconia in the underlayer provides good adhesion to the electrolyte of the fuel cell, while the use of more electrode metal in the overlayer provides good electrical conductivity. The sintered fuel electrode is less expensive to produce compared with conventional electrodes made by electrochemical vapor deposition processes. The sintered electrodes exhibit favorable performance characteristics, including good porosity, adhesion, electrical conductivity and freedom from degradation.

Ruka, Roswell J. (Pittsburgh, PA); Warner, Kathryn A. (Bryan, TX)

1999-01-01

455

Powdered Metal Sintering of Jet Vanes.  

National Technical Information Service (NTIS)

This report presents the successful efforts to use powdered metallurgy techniques in manufacturing jet vanes from sintered and copper infiltrated tungsten. Isostatic pressing of the powdered tungsten to net shape imparts sufficient hardening to allow hand...

M. J. Ripley-Lotee S. M. O'Neil

1982-01-01

456

Sintering Behavior of Diboride Based Materials.  

National Technical Information Service (NTIS)

A brief history of diboride research, an overview of processing, and sintering studies are covered in this viewgraph presentation. UHTCs are a family of ceramic materials, including diborides of Hf and Zr, with extremely high melting temperatures. Spark P...

M. Gasch M. Gusman E. Irby D. Ellerby S. Beckman S. Johnson

2003-01-01

457

Electrical Properties of Low Temperature Sintered Piezoceramics  

Microsoft Academic Search

In general, commercial PZT piezoceramics are sintered at temperature above 1200C. Here, one low-temperature sintering technology was developed for PZT piezoceramics by adding perovskite-type ferroelectrics with low sintering temperature, alternative to adding non-piezoelectric low-melting glass or eutectic oxides. Through solid state reaction mechanism, very densified piezoceramics of (Pb0.95Sr0.05)(Zr0.53Ti0.47)O3 with 0.6PbTiO30.3Bi(Zn0.5Ti0.5)O30.1BiFeO3 as sintering additive were obtained below 1050C. The phase of

Tingting Wang; Feifei An; Jian Yu

2010-01-01

458

Densification of Ceramics by Gas Overpressure Sintering.  

National Technical Information Service (NTIS)

The use of various gas pressure sintering (GPS) techniques for densifying ceramics are reviewed for both oxides and non-oxides. Variations of the process are discussed with respect to process parameters selected, process sequence, and microstructural deve...

G. E. Gazza R. N. Katz

1992-01-01

459

Microwave sintering of multilayer ceramic capacitors.  

National Technical Information Service (NTIS)

Multilayer ceramic capacitors of several compositions (both Z5U and NPO types) were sintered in air in both conventional and microwave furnaces. Several casketing and insulation techniques were used to improve temperature uniformity and minimize dopant lo...

R. J. Lauf C. E. Holcombe C. Hamby

1992-01-01

460

Hypogene Zn carbonate ores in the Angouran deposit, NW Iran  

NASA Astrophysics Data System (ADS)

The world-class Angouran nonsulfide Zn Pb deposit is one of the major Zn producers in Iran, with resources estimated at about 18 Mt at 28% Zn, mainly in the form of the Zn carbonate smithsonite. This study aims to characterize these carbonate ores by means of their mineralogy and geochemistry, which has also been extended to the host rocks of mineralization and other local carbonate rock types, including the prominent travertines in the Angouran district, as well as to the local spring waters. Petrographical, chemical, and stable isotope (O, H, C, Sr) data indicate that the genesis of the Zn carbonate ores at Angouran is fairly distinct from that of other classical nonsulfide Zn deposits that formed entirely by supergene processes. Mineralization occurred during two successive stages, with the zinc being derived from a preexisting sulfide ore body. A first, main stage of Zn carbonates (stage I carbonate ore) is associated with both preexisting and subordinate newly formed sulfides, whereas a second stage is characterized by supergene carbonates (Zn and minor Pb) coexisting with oxides and hydroxides (stage II carbonate ore). The coprecipitation of smithsonite with galena, pyrite and arsenopyrite, as well as the absence of Fe- and Mn-oxides/hydroxides and of any discernible oxidation or dissolution of the sphalerite-rich primary sulfide ore, shows that the fluids responsible for the main, stage I carbonate ores were relatively reduced and close to neutral to slightly basic pH with high fCO2. Smithsonite ?18OVSMOW values from stage I carbonate ore range from 18.3 to 23.6, while those of stage II carbonate ore show a much smaller range between 24.3 and 24.9. The ?13C values are fairly constant in smithsonite of stage I carbonate ore (3.2 6.0) but show a considerable spread towards lower ?13CVPDB values (4.6 to -11.2) in stage II carbonate ore. This suggests a hypogene formation of stage I carbonate ore at Angouran from low-temperature hydrothermal fluids, probably mobilized during the waning stages of Tertiary Quaternary volcanic activity in an environment characterized by abundant travertine systems throughout the whole region. Conversely, stage II carbonate ore is unambiguously related to supergene weathering, as evidenced by the absence of sulfides, the presence of Fe-Mn-oxides and arsenates, and by high ?18O values found in smithsonite II. The variable, but still relatively heavy carbon isotope values of supergene smithsonite II, suggests only a very minor contribution by organic soil carbon, as is generally the case in supergene nonsulfide deposits.

Boni, Maria; Gilg, H. Albert; Balassone, Giuseppina; Schneider, Jens; Allen, Cameron R.; Moore, Farid

2007-11-01

461

Total Ore Processing Integration and Management  

SciTech Connect

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 the predictability of mill and agglomerator performance at Hibtac Mine.

Leslie Gertsch; Richard Gertsch

2006-01-30

462

Silicon nitride: From sintering to joining  

Microsoft Academic Search

In earlier work, silicon nitride (Si3N4) powders were sintered with a mixture of rare-earth oxide (RE2O3) and silica (SiO2). When the chemistry and sintering schedule is carefully controlled, the intergranular phase is a crystalline RE2Si2O7 phase, which imparts improved mechanical and oxidation properties to the Si3N4. Based on the premise that a material that is successful in joining individual grains

Mani Gopal; L. C. De Jonghe; G. Thomas

1998-01-01

463

Physical and electrochemical properties of doped lithium iron phosphate electrodes  

Microsoft Academic Search

Stoichiometric and non-stoichiometric Mg-doped lithium iron phosphates were synthesised via spray-pyrolysis, followed by sintering at high temperature for crystallization. The spray pyrolysis process allows the homogeneous mixing of the ingredient reactants at atomic level. The electronic conductivities of the Mg-doped lithium iron phosphates have been drastically improved by 4 orders of magnitude, comparing to the undoped LiFePO4. The electrochemical properties

G. X. Wang; S. L. Bewlay; K. Konstantinov; H. K. Liu; S. X. Dou; J.-H. Ahn

2004-01-01

464

Constraints on the composition of ore fluids and implications for mineralising events at the Cleo gold deposit, Eastern Goldfields Province, Western Australia  

USGS Publications Warehouse

The Cleo gold deposit, 55 km south of Laverton in the Eastern Goldfields Province of Western Australia, is characterised by banded iron-formation (BIF)-hosted ore zones in the gently dipping Sunrise Shear Zone and high-grade vein-hosted ore in the Western Lodes. There is evidence that gold mineralisation in the Western Lodes (which occurred at ca 2655 Ma) post-dates the majority of displacement along the Sunrise Shear Zone, but it remains uncertain if the ore in both structures formed simultaneously or separately. Overall, the Pb, Nd, Sr, C. O and S isotopic compositions of ore-related minerals from both the Western Lodes and ore zones in the Sunrise Shear Zone are similar. Early low-salinity aqueous-carbonic fluids and late high-salinity fluids with similar characteristics are trapped in inclusions in quartz veins from both the Sunrise Shear Zone and the Western Lodes. The early CO2, CO2-H2O, and H2O- dominant inclusions are interpreted as being related to ore formation, and to have formed from a single low-salinity aqueous-carbonic fluid as a result of intermittent fluid immiscibility. Homogenisation temperatures indicate that these inclusions were trapped at approximately 280??C and at approximately 4 km depth, in the deeper epizonal range. Differences between the ore zones are detected in the trace-element composition of gold samples, with gold from the Sunrise Shear Zone enriched in Ni, Pb, Sn, Te and Zn, and depleted In As, Bi, Cd, Cu and Sb, relative to gold from the Western Lodes. Although there are differences in gold composition between the Sunrise Shear Zone and Western Lodes, and hence the metal content of ore fluids may have varied slightly between the different ore zones, no other systematic fluid or solute differences are detected between the ore zones. Given the fact that the ore fluids in each zone have very similar bulk properties, the considerable differences in gold grade, sulfide mineral abundance, and ore textures between the two ore zones most likely result from different gold-deposition mechanisms. The association of ore zones in the Sunrise Shear Zone with pyrite-replaced BIF suggests that wall-rock sulfidation was the most significant mechanism of gold precipitation, through the destabilisation of gold-bisulfide complexes. The Western Lodes, however, do not exhibit any host-rock preference and multistage veins commonly contain coarse-grained gold. Fluid-inclusion characteristics and breccia textures in veins in the Western Lodes suggest that rapid pressure changes, brought about by intermittent release of overpressured fluids and concomitant phase separation, are likely to have caused the destabilisation of gold-thiocomplexes, leading to formation of higher-grade gold ore zones.

Brown, S. M.; Johnson, C. A.; Watling, R. J.; Premo, W. R.

2003-01-01

465

Hydroxyapatite ceramics with selected sintering additives.  

PubMed

Several sintering additives for hydroxyapatite (HA) have been tested in order to enhance its sinterability without decomposing the HA and/or decreasing bioactivity and biocompatibility, additionally providing a weak interface for HA ceramics. The ion species of sintering additives were selected from those in the mineral constituents of hard tissues and bioactive glasses. After investigation of phase diagrams in the CaO-P2O5-additive systems, and analysis of physiochemical properties of the additives, several sintering aids for HA have been chosen. Subsequently, densification, phase composition, grain growth and fracture behaviour of HA containing 5 wt% of each additive, sintered at 1000-1100 degrees C, have been studied. H3BO3, CaCl2, KCl, KH2PO4, (KPO3)n and Na2Si2O5 did not enhance densification of HA. K2CO2, Na2CO3, KF and sodium phosphates improved the densification significantly. Expect for KCl and some sodium phosphates, all the additives caused formation of large quantities of undesired beta-tricalcium phosphate or CaO; therefore, they are not appropriate for HA. In the case of sodium phosphate additives, it was possible to avoid formation of CaO or beta-tricalcium phosphate by control of the additive quantity and chemical composition. beta-NaCaPO4 has been found to be an effective sintering agent which causes neither decomposition of HA nor formation of other undesired phases. PMID:9199762

Suchanek, W; Yashima, M; Kakihana, M; Yoshimura, M

1997-07-01

466

Microstructural and continuum evolution modeling of sintering.  

SciTech Connect

All ceramics and powder metals, including the ceramics components that Sandia uses in critical weapons components such as PZT voltage bars and current stacks, multi-layer ceramic MET's, ahmindmolybdenum & alumina cermets, and ZnO varistors, are manufactured by sintering. Sintering is a critical, possibly the most important, processing step during manufacturing of ceramics. The microstructural evolution, the macroscopic shrinkage, and shape distortions during sintering will control the engineering performance of the resulting ceramic component. Yet, modeling and prediction of sintering behavior is in its infancy, lagging far behind the other manufacturing models, such as powder synthesis and powder compaction models, and behind models that predict engineering properties and reliability. In this project, we developed a model that was capable of simulating microstructural evolution during sintering, providing constitutive equations for macroscale simulation of shrinkage and distortion during sintering. And we developed macroscale sintering simulation capability in JAS3D. The mesoscale model can simulate microstructural evolution in a complex powder compact of hundreds or even thousands of particles of arbitrary shape and size by 1. curvature-driven grain growth, 2. pore migration and coalescence by surface diffusion, 3. vacancy formation, grain boundary diffusion and annihilation. This model was validated by comparing predictions of the simulation to analytical predictions for simple geometries. The model was then used to simulate sintering in complex powder compacts. Sintering stress and materials viscous module were obtained from the simulations. These constitutive equations were then used by macroscopic simulations for simulating shrinkage and shape changes in FEM simulations. The continuum theory of sintering embodied in the constitutive description of Skorohod and Olevsky was combined with results from microstructure evolution simulations to model shrinkage and deformation during. The continuum portion is based on a finite element formulation that allows 3D components to be modeled using SNL's nonlinear large-deformation finite element code, JAS3D. This tool provides a capability to model sintering of complex three-dimensional components. The model was verified by comparing to simulations results published in the literature. The model was validated using experimental results from various laboratory experiments performed by Garino. In addition, the mesoscale simulations were used to study anisotropic shrinkage in aligned, elongated powder compacts. Anisotropic shrinkage occurred in all compacts with aligned, elongated particles. However, the direction of higher shrinkage was in some cases along the direction of elongation and in other cases in the perpendicular direction depending on the details of the powder compact. In compacts of simple-packed, mono-sized, elongated particles, shrinkage was higher in the direction of elongation. In compacts of close-packed, mono-sized, elongated particles and of elongated particles with a size and shape distribution, the shrinkage was lower in the direction of elongation. We also explored the concept of a sintering stress tensor rather than the traditional sintering stress scalar concept for the case of anisotropic shrinkage. A thermodynamic treatment of this is presented. A method to calculate the sintering stress tensor is also presented. A user-friendly code that can simulate microstructural evolution during sintering in 2D and in 3D was developed. This code can run on most UNIX platforms and has a motif-based GUI. The microstructural evolution is shown as the code is running and many of the microstructural features, such as grain size, pore size, the average grain boundary length (in 2D) and area (in 3D), etc. are measured and recorded as a function of time. The overall density as the function of time is also recorded.

Braginsky, Michael V.; Olevsky, Eugene A. (San Diego State University, San Diego, CA); Johnson, D. Lynn (Northwest University, Evanston, IL); Tikare, Veena; Garino, Terry J.; Arguello, Jose Guadalupe, Jr.

2003-12-01

467

Liquid phase sintering of tungsten composites under microgravity: Influence of liquid/particle surface energy  

NASA Astrophysics Data System (ADS)

Tungsten-nickel-iron heavy metals are fabricated from powders by liquid phase sintering. A study of the sintering mechanism of heavy metals with a low amount of tungsten particles can, depending on sedimentation, only be done under microgravity. At two earlier Texus flights, No 10 & 19, the growth rate and agglomeration of tungsten particles under microgravity were compared to that under gravity and sedimentation. During the first minute sintering period the particles in the agglomerates were separated and the particle distribution became even. The particle growth rate under microgravity, initially high, is slowing down. At further studies under gravity the influence of surface energy between the liquid phase and the tungsten particles have been investigated. Additions of sulphur and cobolt were used to decrease the surface energy and the use of nickel without iron to increase the energy. At a high surface energy the growth rate increases due to increased driving force. Preliminary results from the Texus 26 flight (April 90) are included.

Ekbom, L. B.; Lei, B.; Eliasson, A.; Jarfors, A.

468

Dissolution and recovery of aluminum and other metals from Calsinter process sinter product  

SciTech Connect

In the Calsinter process for the recovery of aluminum and other metals, fly ash is sintered with a source of calcium oxide at 1000 to 1200/sup 0/C, and the sinter product leached with dilute sulfuric acid. The leach step parameters have been optimized following a sinter of eastern Tennessee fly ash with limestone. Batch rate studies have shown that near maximum aluminum solubilization was achieved in 1 h at ambient temperature with 4N H/sub 2/SO/sub 4/ at 20% pulp density. A three-stage batch countercurrent leach system was operated under steady-state conditions in which only 2.2 moles of H/sub 2/SO/sub 4/ were required per mole of Al/sub 2/O/sub 3/ solubilized. Solubilization of aluminum (97%), iron (97%), titanium (82%), a