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Sample records for reef ore flotation

  1. Beneficiation of the gold bearing ore by gravity and flotation

    NASA Astrophysics Data System (ADS)

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

    2012-02-01

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

  2. Hydrothermal Sulfidation and Flotation of Oxidized Zinc-Lead Ore

    NASA Astrophysics Data System (ADS)

    Li, Cun-Xiong; Wei, Chang; Deng, Zhi-Gan; Li, Xing-Bin; Li, Min-Ting; Xu, Hong-Sheng

    2014-06-01

    The sample with smithsonite and cerussite as the main valuable metal minerals is a carbonate-hosted lead-zinc ore in the current study. Hydrothermal sulfidation of oxidized zinc-lead ore was carried out with a particle size of 74 to 58 μm and the mole ratio of sulfur and zinc of 2.0 at 453 K (180 °C) for 240 minutes, and 73 pct zinc and 86 pct lead sulfidation fraction were achieved. Flotation of the unsulfided sample was ineffective, with less than 55 pct recovery of zinc and lead. After sulfidation, the recoveries of zinc and lead in flotation concentrate were over 92 pct. A flotation concentrate was obtained with zinc and lead content of 41.2 pct and 22.1 pct, respectively.

  3. Direct Flotation of Niobium Oxide Minerals from Carbonatite Niobium Ores

    NASA Astrophysics Data System (ADS)

    Ni, Xiao

    Currently the recovery of niobium oxide minerals from carbonatite niobium ores relies on the use of non-selective cationic collectors. This leads to complicated process flowsheets involving multiple desliming and multiple reverse flotation stages, and low niobium recovery. In this research, anionic collectors that are capable of strong chemisorption on the niobium minerals were studied with the objective of directly floating the niobium oxide minerals from the carbonatite ores. In the flotation of both high purity minerals and Niobec ores, it was shown that the combination of hydroxamic acid and sodium metaphosphate was an effective reagent scheme for the direct flotation of niobium oxide from its ores. Batch flotation on the Niobec Mill Feed showed that over 95% of niobium oxide was recovered into a rougher concentrate that was less than 47% of the original feed mass. Preliminary cleaning tests showed that the reagent scheme could also be used to upgrade the rougher concentrate, although the depression of iron oxide minerals required further study. X-ray photoelectron spectroscopic (XPS) measurement results confirm that OHA (octyl hydroxamic acid) could chemisorb on pyrochlore surface while only physically adsorb on calcite, judging by the chemical shifts of electron binding energies in the elements in both OHA and the mineral surfaces. When hydroxamic acid was adsorbed on calcite surface, the binding energies of the N 1s electrons, at 400.3 eV, did not shift. However, after adsorption on pyrochlore, the N 1s binding energy peak split into two peaks, one at a binding energy of around 399 eV, representing chemically adsorbed OHA, the other at between 400 and 401 eV. The experimental data suggested a strong chemisorption of the OHA on pyrochlore surface in the form of a vertical head-on orientation of the OHA molecules so that the pyrochlore was strongly hydrophobized even at low OHA concentrations, followed by possibly randomly oriented physisorbed OHA molecules. On the other hand, OHA only physisorbed on calcite forming a horizontally oriented monolayer of OHA. The results explain the observed selectivity of hydroxamic acid in the flotation of niobium oxide minerals from carbonatite niobium ores.

  4. Beneficiation of flotation tailing from Polish copper sulfide ores

    SciTech Connect

    Luszczkiewicz, A.; Sztaba, K.S.

    1995-12-31

    Flotation tailing of Polish copper sulfide ores represents more than 90% of the mass of run-of-mine ore. The tailing contains mainly quartz, dolomite, clay minerals, traces of sulfides, and some accessory minerals. Almost all minerals of the tailing are well liberated and, therefore, any further beneficiation process applied to the tailing is expected to be inexpensive. In this work, results of investigations on utilization of flotation tailing using classification and gravity concentration are presented. It is shown that due to classification of flotation tailing in hydrocyclones, the coarse fraction becomes suitable material for gravity separation providing backfill material for underground mines as well as heavy minerals, a source of valuable rare elements. It was also found that heavy minerals separated by gravity methods contain a significant amount of rare elements such as zirconium, titanium, silver, rare earth metals, and uranium. The light fraction of the gravity separation contains well deslimed quartz particles and meets strict requirements for hydraulic filling material used for structural support in underground mines. Evaluation of the cost of the proposed technology indicated that investment to implement the method would provide a return within 2--4 years.

  5. Nickel Ore Dispersion Evaluation and Consequences in Flotation Process

    NASA Astrophysics Data System (ADS)

    de São José, Fábio; Imbelloni, Alaine Moreira; Nogueira, Francielle Câmara; Pereira, Carlos Alberto

    2016-04-01

    Nickel ore dispersion before flotation using different reagents was investigated on a bench scale to improve metallurgical recovery and selectivity. The nickel ore had a content of 0.8 pct nickel and 14.5 pct MgO. A positive linear correlation between MgO and Ni was found. Carboxy methyl cellulose, both pure and combined with Na2CO3, was the best dispersant used. The most efficient collector was potassium amyl xanthate combined with mercaptobenzothiazole, and the addition of xanthate was decisive for this good result because it is normally more stable in the pH range used in the tests. A pH change from 7 to 9 resulted in a metal recovery increase of 49.3 pct, together with an increase of 6.25 pct of MgO in the concentrate.

  6. Nickel Ore Dispersion Evaluation and Consequences in Flotation Process

    NASA Astrophysics Data System (ADS)

    de So Jos, Fbio; Imbelloni, Alaine Moreira; Nogueira, Francielle Cmara; Pereira, Carlos Alberto

    2016-01-01

    Nickel ore dispersion before flotation using different reagents was investigated on a bench scale to improve metallurgical recovery and selectivity. The nickel ore had a content of 0.8 pct nickel and 14.5 pct MgO. A positive linear correlation between MgO and Ni was found. Carboxy methyl cellulose, both pure and combined with Na2CO3, was the best dispersant used. The most efficient collector was potassium amyl xanthate combined with mercaptobenzothiazole, and the addition of xanthate was decisive for this good result because it is normally more stable in the pH range used in the tests. A pH change from 7 to 9 resulted in a metal recovery increase of 49.3 pct, together with an increase of 6.25 pct of MgO in the concentrate.

  7. Estimated water requirements for the conventional flotation of copper ores

    USGS Publications Warehouse

    Bleiwas, Donald I.

    2012-01-01

    This report provides a perspective on the amount of water used by a conventional copper flotation plant. Water is required for many activities at a mine-mill site, including ore production and beneficiation, dust and fire suppression, drinking and sanitation, and minesite reclamation. The water required to operate a flotation plant may outweigh all of the other uses of water at a mine site, [however,] and the need to maintain a water balance is critical for the plant to operate efficiently. Process water may be irretrievably lost or not immediately available for reuse in the beneficiation plant because it has been used in the production of backfill slurry from tailings to provide underground mine support; because it has been entrapped in the tailings stored in the TSF, evaporated from the TSF, or leaked from pipes and (or) the TSF; and because it has been retained as moisture in the concentrate. Water retained in the interstices of the tailings and the evaporation of water from the surface of the TSF are the two most significant contributors to water loss at a conventional flotation circuit facility.

  8. Dolomite flotation of high magnesium phosphate ores using fatty acid soap collectors

    NASA Astrophysics Data System (ADS)

    Gu, Zhengxing

    The separation of dolomite from apatite has been recognized as one of the most difficult subjects in mineral processing due to the similarities in their physiochemical properties. In this study, selective surfactants were used with a fatty acid soap collector to improve the flotation performance of separating dolomite from high magnesium phosphate ores. Three surfactants, diethyl phthalate (DP), Tween-80 (TW) and derivative of sulfonate salt (DSS1) were used. Hallimond cell flotation was conducted using pure dolomite sample to determine the effects of various factors including dosages, particle size, Ca2+ ions and slimes on the dolomite flotation recovery. The results showed that the surfactants can significantly improve dolomite flotation performance by increasing collecting ability and tolerating the effect of calcium ions and slime contents. The stirrer-tank cell batch flotation tests were carried out using two natural high magnesium phosphate ore samples containing 3.3% and 1.5% MgO. The test results showed that the surfactant DP could improve dolomite flotation at low dosages, and DSS1 could enhance the separation of dolomite from phosphate by improving both collecting ability and flotation selectivity. When 10% of DSS1 was used with the fatty acid soap as collector, at least 10% more dolomite can be removed with less P2O5 loss. The effectiveness of the surfactant DSS1 in enhancing dolomite flotation was further demonstrated in modified packed column flotation with natural dolomitic phosphate ore sample. The addition of the surfactant DSS1 into fatty acid soap collector could improve its frothability and froth stability, and reduce the bubble size. It has been found that the dolomite flotation performance has a close relationship with the frothability and froth stability of the collector.

  9. Effects of High Pressure ORE Grinding on the Efficiency of Flotation Operations

    NASA Astrophysics Data System (ADS)

    Saramak, Daniel; Krawczykowska, Aldona; Młynarczykowska, Anna

    2014-10-01

    This article discusses issues related to the impact of the high pressure comminution process on the efficiency of the copper ore flotation operations. HPGR technology improves the efficiency of mineral resource enrichment through a better liberation of useful components from waste rock as well as more efficient comminution of the material. Research programme included the run of a laboratory flotation process for HPGR crushing products at different levels of operating pressures and moisture content. The test results showed that products of the high-pressure grinding rolls achieved better recoveries in flotation processes and showed a higher grade of useful components in the flotation concentrate, in comparison to the ball mill products. Upgrading curves have also been marked in the following arrangement: the content of useful component in concentrate the floatation recovery. All upgrading curves for HPGR products had a more favourable course in comparison to the curves of conventionally grinded ore. The results also indicate that various values of flotation recoveries have been obtained depending on the machine operating parameters (i.e. the operating pressure), and selected feed properties (moisture).

  10. Water leaching of titanium from ore flotation residue

    SciTech Connect

    Jaworska, Malgorzata M.; Guibal, Eric

    2003-07-01

    Copper ore tailings were tested for the stability of titanium submitted to water leaching in three different reactor systems (agitated vessel, bioreactor and percolated fixed-bed column). For each of these systems, titanium extraction did not exceed 1% of the available metal. Biomass removed from ore residue adsorbed a small part of the titanium with sorption capacities below 20-30 mg g{sup -1}, but most of this biomass was sequestered in the ore residue. Oxygen and carbon dioxide concentrations were monitored and changes in concentration correlated with bacteria development at the initial stage of the process and to fungal development in the latter stages.

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

    PubMed

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

    2012-01-01

    A new phenomenon has been identified and studied-the impact of bacteria on the benefication process of non-sulphide ores using circulating water supply-a case study of apatite-nepheline ore. It is shown that bacteria deteriorate the floatability of apatite due to their interaction with active centres of calcium-containing minerals and intense flocculation, resulting in a decrease of the flotation process selectivity thus deteriorating the quality of concentrate. Based on the comparative analysis of primary sequences of 16S rRNA genes, there have been identified dominating bacteria species, recovered from the circulating water used at apatite-nepheline concentrating mills, and their phylogenetic position has been determined. All the bacteria were related to ?-Proteobacteria, including the Acinetobacter species, Pseudomonas alcaliphila, Ps. plecoglossicida, Stenotrophomonas rhizophila. A method of non-sulphide ores flotation has been developed with consideration of the bacterial factor. It consists in use of small concentrations of sodium hypochlorite, which inhibits the development of bacteria in the flotation of apatite-nepheline ores. PMID:22320692

  12. [Thermoacidophilic micirobial community oxidizing the gold-bearing flotation concentrate of a pyrite-arsenopyrite ore].

    PubMed

    Paniushkina, A E; Tsaplina, I A; Grigor'eva, N V; Kondrat'eva, T F

    2014-01-01

    An aboriginal community of thermophilic acidophilic chemolithotrophic microorganisms (ACM) was isolated from a sample of pyrite gold-bearing flotation concentrateat 45-47 degrees C and pH 1.8-2.0. Compared to an experimental thermoacidophilic microbial consortium formed in the course of cultivation in parallel bioreactors, it had lower rates of iron leaching and oxidation, while its rate of sulfur oxidation was higher. A new thermophilic acidophilic microbial community was obtained by mutual enrichment with the micioorganisms from thie experimental and aboriginal communities during oxidation of sulfide ore flotation concentrate at 47 degrees C. The dominant bacteria of this new ACM community were Acidithiobacillus caldus strains (the most active sulfur oxidizers) and Sulfobacillus thermotolerans strains (active oxidizers of both iron and sulfur), while iron-oxidizing archaea of the family Ferroplasmaceae and heterotrophic bacteria Alicyclobacillus tolerans were the minor components. The new ACM community showed promise for leaching/oxidation of sulfides from flotation concentrates at high pulp density (S:L = 1:4). PMID:25844467

  13. Isolation and characterization of lost copper and molybdenum particles in the flotation tailings of Kennecott copper porphyry ores

    NASA Astrophysics Data System (ADS)

    Tserendavga, Tsend-Ayush

    The importance of flotation separation has long been, and continues to be, an important technology for the mining industry, especially to metallurgical engineers. However, the flotation process is quite complex and expensive, in addition to being influenced by many variables. Understanding the variables affecting flotation efficiency and how valuable minerals are lost to the tailings gives metallurgists an advantage in their attempts to increase efficiency by designing operations to target the areas of greatest potential value. A successful, accurate evaluation of lost minerals in the tailings and appropriate solutions to improve flotation efficiency can save millions of dollars in the effective utilization of our mineral resources. In this dissertation research, an attempt has been made to understand the reasons for the loss of valuable mineral particles in the tailings from Kennecott Utah Copper ores. Possibilities include liberation, particle aggregation (slime coating) and surface chemistry issues associated with the flotation separation. This research generally consisted of three main aspects. The first part involved laboratory flotation experiments and factors, which affect the flotation efficiency. Results of flotation testing are reported that several factors such as mineral exposure/liberation and slime coating and surface oxidation strongly affect the flotation efficiency. The second part of this dissertation research was to develop a rapid scan dual energy (DE) methodology using 2D radiography to identify, isolate, and prepare lost sulfide mineral particles with the advantages of simple sample preparation, short analysis time, statistically reliable accuracy and confident identification. The third part of this dissertation research was concerned with detailed characterization of lost particles including such factors as liberation, slime coating, and surface chemistry characteristics using advanced analytical techniques and instruments. Based on the results from characterization, the extent to which these factors contribute to the loss of sulfide mineral particles in the tailings were determined.

  14. Effectiveness of sodium silicate as gangue depressants in iron ore slimes flotation

    NASA Astrophysics Data System (ADS)

    Rao, Danda Srinivas; Vijayakumar, Tadiparthi Venkata; Rao, Sripada Subba; Prabhakar, Swarna; Raju, Guntamadugu Bhaskar

    2011-10-01

    The recovery of iron from the screw classifier overflow slimes by direct flotation was studied. The relative effectiveness of sodium silicates with different silica-to-soda mole ratios as depressants for silica and silicate bearing minerals was investigated. Silica-to-soda mole ratio and silicate dosage were found to have significant effect on the separation efficiency. The results show that an increase of Fe content in the concentrate is observed with concomitant reduction in SiO2 and Al2O3 levels when a particular type of sodium silicate at a proper dosage is used. The concentrate of 58.89wt% Fe, 4.68wt% SiO2, and 5.28wt% Al2O3 with the weight recovery of 38.74% and the metal recovery of 41.13% can be obtained from the iron ore slimes with 54.44wt% Fe, 6.72wt% SiO2, and 6.80wt% Al2O3, when Na2SiO3 with a silica-to-soda mole ratio of 2.19 is used as a depressant at a feed rate of 0.2 kg/t.

  15. Electrochemical pretreatment of recycled water in flotation of non-sulfide and diamond-containing ores

    SciTech Connect

    Chanturiya, V.A.; Trofimova, E.A.; Dvoichenkova, G.P.; Zaskevich, M.V.

    1995-12-31

    The paper presents theoretical and practical aspects of directed adjustment of the physicochemical properties (pH,Eh) and ion composition of recycle and mine water by an electrochemical treatment. Treatment is run in diaphragm-type conditioners with production of alkaline catholyte of pH value up to 12 and acidic anolyte of pH up to 2. In the process of water electrolysis the directed motion of Mg{sup 2+} and Ca{sup 2+} ions is observed from anode volume to cathode one, where they precipitate as hydroxides and carbonates; it leads to a decrease of salt content in anolyte and catholyte. The results of experimental and industrial testing of the electrochemical technique for mine and recycle water in flotation of diamond-containing and sulfide-scheelite, hematite, phosphorite, apatite-nephelite, bauxite ores indicated the increase of recovery up to 2--15% and grade up to 0.5--2%, concurrent with a decrease of reagent consumption from 15 to 50%. Modules of industrial conditioners of different type capacity have been developed.

  16. The theory of flotation

    NASA Technical Reports Server (NTRS)

    Ostwald, Wolfgang

    1988-01-01

    A brief summary of the fundamentals of the Linear theory of flotation is given. The theory by no means contradicts the previous Laminar theory or even the thermodynamics (Wark-Siedler), rather it is a refinement of the known Hardy-Langmuir-Harkin conceptions for the case when there are not two phases and phase boundaries, but rather three phases and corresponding phase boundary edges. The appearance of such three-phase boundaries (ore, water, air) is characteristic for modern flotation methods.

  17. [Effect of temperature on the rate of oxidation of pyrrhotite-rich sulfide ore flotation concentrate and the structure of the acidophilic chemolithoautotrophic microbial community].

    PubMed

    Moshchanetskii, P V; Pivovarova, T A; Belyi, A V; Kondrat'eva, T F

    2014-01-01

    Oxidation of flotation concentrate of a pyrrhotite-rich sulfide ore by acidophilic chemolithoautotrophic microbial communities at 35, 40, and 45 degrees C was investigated. According to the physicochemical parameters of the liquid phase of the pulp, as well as the results of analysis of the solid residue after biooxidation and cyanidation, the community developed at 40 degrees C exhibited the highest rate of oxidation. The degree of gold recovery at 35, 40, and 45 degrees C was 89.34, 94.59, and 83.25%, respectively. At 40 degrees C, the highest number of microbial cells (6.01 x 10(9) cells/mL) was observed. While temperature had very little effect on the species composition of microbial communities, except for the absence of Leptospirillum ferriphilum at 35 degrees C, the shares of individual species in the communities varied with temperature. Relatively high numbers of Sulfobacillus thermosulfidooxidans, the organism oxidizing iron and elemental sulfur at higher rates than other acidophilic chemolithotrophic species, were observed at 40 degrees C. PMID:25844443

  18. Determination of gold in copper-bearing sulphide ores and metallurgical flotation products by atomic-absorption spectrometry.

    PubMed

    Strong, B; Murray-Smith, R

    1974-12-01

    A method is described which is specific for the determination of gold in sulphide copper ores and concentrates. Direct decomposition with aqua regia was found to be incomplete. A carefully controlled roasting stage followed by treatment with hydrochloric acid and then aqua regia was effective for dissolving all the gold. The gold is extracted into 4-methylpentan-2-one (methyli-sobutylketone) then aspirated into a very lean air-acetylene flame and the gold determined by atomic-absorption spectrometry. No interferences were observed from large concentrations of copper, iron or nickel. PMID:18961594

  19. Flotation separation of waste plastics for recycling-A review.

    PubMed

    Wang, Chong-qing; Wang, Hui; Fu, Jian-gang; Liu, You-nian

    2015-07-01

    The sharp increase of plastic wastes results in great social and environmental pressures, and recycling, as an effective way currently available to reduce the negative impacts of plastic wastes, represents one of the most dynamic areas in the plastics industry today. Froth flotation is a promising method to solve the key problem of recycling process, namely separation of plastic mixtures. This review surveys recent literature on plastics flotation, focusing on specific features compared to ores flotation, strategies, methods and principles, flotation equipments, and current challenges. In terms of separation methods, plastics flotation is divided into gamma flotation, adsorption of reagents, surface modification and physical regulation. PMID:25869841

  20. Magmatic ore deposits in layered intrusions - Descriptive model for reef-type PGE and contact-type Cu-Ni-PGE deposits

    USGS Publications Warehouse

    Zientek, Michael L.

    2012-01-01

    Layered, ultramafic to mafic intrusions are uncommon in the geologic record, but host magmatic ore deposits containing most of the world's economic concentrations of platinum-group elements (PGE) (figs. 1 and 2). These deposits are mined primarily for their platinum, palladium, and rhodium contents (table 1). Magmatic ore deposits are derived from accumulations of crystals of metallic oxides, or immiscible sulfide, or oxide liquids that formed during the cooling and crystallization of magma, typically with mafic to ultramafic compositions. "PGE reefs" are stratabound PGE-enriched lode mineralization in mafic to ultramafic layered intrusions. The term "reef" is derived from Australian and South African literature for this style of mineralization and used to refer to (1) the rock layer that is mineralized and has distinctive texture or mineralogy (Naldrett, 2004), or (2) the PGE-enriched sulfide mineralization that occurs within the rock layer. For example, Viljoen (1999) broadly defined the Merensky Reef as "a mineralized zone within or closely associated with an unconformity surface in the ultramafic cumulate at the base of the Merensky Cyclic Unit." In this report, we will use the term PGE reef to refer to the PGE-enriched mineralization, not the host rock layer. Within a layered igneous intrusion, reef-type mineralization is laterally persistent along strike, extending for the length of the intrusion, typically tens to hundreds of kilometers. However, the mineralized interval is thin, generally centimeters to meters thick, relative to the stratigraphic thickness of layers in an intrusion that vary from hundreds to thousands of meters. PGE-enriched sulfide mineralization is also found near the contacts or margins of layered mafic to ultramafic intrusions (Iljina and Lee, 2005). This contact-type mineralization consists of disseminated to massive concentrations of iron-copper-nickel-PGE-enriched sulfide mineral concentrations in zones that can be tens to hundreds of meters thick. The modes and textures of the igneous rocks hosting the mineralization vary irregularly on the scale of centimeters to meters; autoliths and xenoliths are common. Mineralization occurs in the igneous intrusion and in the surrounding country rocks. Mineralization can be preferentially localized along contact with country rocks that are enriched in sulfur-, iron-, or CO2-bearing lithologies. Reef-type and contact-type deposits, in particular those in the Bushveld Complex, South Africa, are the world's primary source of platinum and rhodium (tables 2 and 3; fig. 2). Reef-type PGE deposits are mined only in the Bushveld Complex (Merensky Reef and UG2), the Stillwater Complex (J-M Reef), and the Great Dyke (Main Sulphide Layer). PGE-enriched contact-type deposits are only mined in the Bushveld Complex. The other deposits in tables 2 and 3 are undeveloped; some are still under exploration.

  1. Flotation separation of coal concentrates. 1976-1981 (citations from the Energy Data Base). Report for Jan 76-Dec 81

    SciTech Connect

    Not Available

    1981-12-01

    Reports are cited which discuss flotation separation of mineral particles using the different surface chemical properties to cause the selected particles to float. Coal-washery flotation circuits are emphasized. Sorting and separating using compressed air jets into the mineral concentration, flotation reagent effects on coal concentrate quality, and economy of flotation separation of coal concentrates are included in this bibliography. Froth flotation, foam separation, and foam flotation processes are included with respect to oil and water mixtures, ore concentrates, and minerals, as well as coal concentrates. (Contains 213 citations fully indexed and including a title list.)

  2. Method and apparatus for concentration of minerals by froth flotation

    SciTech Connect

    Hicks, G.W.; Cornell, W.L.

    1995-07-01

    The invention provides a froth flotation apparatus which employs a series of stationary baffles to create the required turbulence for separation of mineral ores from a mineral slurry without requiring a special apparatus for the generation of microbubbles. Each of the stationary baffles is designed to create a quiescent flow zone from which the non-floatable gangue may be removed from the flotation column.

  3. Pressure flotation of nitrocellulose fines: Hydrodynamics and interfacial chemistry

    SciTech Connect

    Grasso, D.; Hu, H.L.; LaFrance, P.; Kim, B.J.

    1996-11-01

    The production of nitrocellulose (NC) creates large quantities of waste NC fines in wash water streams. Current processing techniques attempt to remove these fines by cross-flow microfiltration, pressure flotation, settling, centrifugation, and lime precipitation. Pressure flotation, or dissolved air flotation (DAF), is a solid/liquid separation process first developed in the ore processing industry. DAF has since found many applications in the environmental engineering field including: drinking water clarification, sludge thickening, and the clarification of wastewater from a variety of industrial and municipal processes. The work presented herein is part of a larger effort to explore techniques to recover and reuse nitrocellulose (NC) fines resulting from propellant manufacturing processes. Previous papers investigated NC particle stability and interfacial thermodynamics and developed a flotation trajectory model. This paper builds on that work and presents a sensitivity analysis of the flotation trajectory model. The sensitivity analysis explores both operational and parameter estimation uncertainty.

  4. Beneficiation of borax by reverse flotation in boron saturated brine.

    PubMed

    Cafer Cilek, Emin; Uresin, Hasan

    2005-10-15

    Flotation is one of the plausible methods for recovering borax fines discharged as fine waste to the tailings dam in the Kirka borax processing plant. A literature review dealing with the flotation behavior of boron minerals reveals that clay minerals in the boron ores coat boron minerals and thus deteriorate the quality of boron concentrates produced by direct flotation. The main objective of this study is therefore to recover borax fines from the tailings of the concentrator by reverse flotation. A three-level-factor experimental design was used to determine the main and interaction effects of variables selected on the metallurgical performance of reverse flotation. An analysis of variance for experimental results indicates that interaction effects of the variables for concentrate quality and recovery of B2O3 is nonsignificant and the most important variable for grade of concentrate and recovery is the collector dosage. It is shown that a concentrate assaying 11.25% B2O3 with 89.90% B2O3 recovery could be produced by means of single-stage (rougher) reverse flotation. Additionally, in order to produce a sufficient-quality concentrate, a multistage reverse flotation scheme involving rougher, scavenger, and two cleaners was devised. A final concentrate containing 23.47% B2O3 with 81.78% B2O3 recovery was obtained from these tests. The reverse flotation method can be thus considered as an important option for the beneficiation of borax fines. PMID:15939429

  5. A review of zinc oxide mineral beneficiation using flotation method.

    PubMed

    Ejtemaei, Majid; Gharabaghi, Mahdi; Irannajad, Mehdi

    2014-04-01

    In recent years, extraction of zinc from low-grade mining tailings of oxidized zinc has been a matter of discussion. This is a material which can be processed by flotation and acid-leaching methods. Owing to the similarities in the physicochemical and surface chemistry of the constituent minerals, separation of zinc oxide minerals from their gangues by flotation is an extremely complex process. It appears that selective leaching is a promising method for the beneficiation of this type of ore. However, with the high consumption of leaching acid, the treatment of low-grade oxidized zinc ores by hydrometallurgical methods is expensive and complex. Hence, it is best to pre-concentrate low-grade oxidized zinc by flotation and then to employ hydrometallurgical methods. This paper presents a critical review on the zinc oxide mineral flotation technique. In this paper, the various flotation methods of zinc oxide minerals which have been proposed in the literature have been detailed with the aim of identifying the important factors involved in the flotation process. The various aspects of recovery of zinc from these minerals are also dealt with here. The literature indicates that the collector type, sulfidizing agent, pH regulator, depressants and dispersants types, temperature, solid pulp concentration, and desliming are important parameters in the process. The range and optimum values of these parameters, as also the adsorption mechanism, together with the resultant flotation of the zinc oxide minerals reported in the literature are summarized and highlighted in the paper. This review presents a comprehensive scientific guide to the effectiveness of flotation strategy. PMID:23571227

  6. Advances in flotation technology

    SciTech Connect

    Parekh, B.K.; Miller, J.D.

    1999-07-01

    The ability to selectively separate fine and coarse particles by flotation is the heart of most mineral processing operations. Significant developments in flotation technology are reflected in this proceedings including: equipment design and development, instrumentation and control, sulfides and precious metals, nonsulfide minerals, coal cleaning, and fundamentals.

  7. The Bateman Flotation Machine

    SciTech Connect

    Bezuidenhout, G.

    1995-12-31

    The newly developed Bateman Flotation Machine has proven its versatility in roughing and cleaning flotation circuits. This mechanical flotation machine has the dual performance capability of suspending solids and dispersing air at relatively low power inputs without compromising these two important fundamentals. This new development has been successfully marketed to a wide cross section of concentrator mineral processes. The mechanical design of the flotation mechanism has been optimized to reduce operational costs and to lower manufacturing costs. Production process environments were utilized for verification of the scale-up of each cell volume size rated mechanism. These thorough investigations produced performance data which could be accurately quoted. This paper is a historical account of the Batement Flotation Machine. Technical details of the development are covered with descriptions of the operational applications.

  8. Ore and coal beneficiation method

    SciTech Connect

    Abadi, K.

    1987-10-27

    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.

  9. Host-rock controlled epigenetic, hydrothermal metasomatic origin of the Bayan Obo REEFe-Nb ore deposit, Inner Mongolia, P.R.C.

    USGS Publications Warehouse

    Chao, E.C.T.; Back, J.M.; Minkin, J.A.; Yinchen, R.

    1992-01-01

    Bayan Obo, a complex rare earth element (REE)FeNb ore deposit, located in Inner Mongolia, P.R.C. is the world's largest known REE deposit. The deposit is chiefly in a marble unit (H8), but extends into an overlying unit of black shale, slate and schist unit (H9), both of which are in the upper part of the Middle Proterozoic Bayan Obo Group. Based on sedimentary structures, the presence of detrital quartz and algal fossil remains, and the 16-km long geographic extent, the H8 marble is a sedimentary deposit, and not a carbonatite of magmatic origin, as proposed by some previous investigators. The unit was weakly regionally metamorphosed (most probably the lower part of the green schist facies) into marble and quartzite prior to mineralization. Tectonically, the deposit is located on the northern flank of the Sino-Korean craton. Many hypotheses have been proposed for the origin of the Bayan Obo deposit; the studies reported here support an epigenetic, hydrothermal, metasomatic origin. Such an origin is supported by field and laboratory textural evidence; 232Th/208Pb internal isochron mineral ages of selected monazite and bastnaesite samples; 40Ar/39Ar incremental heating minimum mineral ages of selected alkali amphiboles; chemical compositions of different generations of both REE ore minerals and alkali amphiboles; and evidence of host-rock influence on the various types of Bayan Obo ores. The internal isochron ages of the REE minerals indicate Caledonian ages for various episodes of REE and Fe mineralization. No evidence was found to indicate a genetic relation between the extensive biotite granitic rocks of Hercynian age in the mine region and the Bayan Obo are deposit, as suggested by previous workers. ?? 1992.

  10. Floatability study of graphite ore from southeast Sulawesi (Indonesia)

    NASA Astrophysics Data System (ADS)

    Florena, Fenfen Fenda; Syarifuddin, Fahmi; Hanam, Eko Sulistio; Trisko, Nici; Kustiyanto, Eko; Enilisiana, Rianto, Anton; Arinton, Ghenadi

    2016-02-01

    Graphite ore obtained from Kolaka Regency, South East Sulawesi, Indonesia have been succesfully investigated for beneficiation by froth flotation technique. Preliminary study have been done to determine the minerals types, fixed carbon content and liberation size of the graphite. Graphite is naturally floatable due to its hydrophobic property. Some suitable reagents are usually added to increase effectiveness of recovery. In this article, enrichment of graphite by froth flotation was studied by investigating the effect of reagents concentrations, rotation speed and particle size on the carbon grade and recovery of the concentrate. The carbon grade increased from 3.00% to 60.00% at the optimum flotation conditions.

  11. New technology for mineral flotation based on pulp-air down-flow apparatus

    SciTech Connect

    Leonov, S.B.; Polonsky, S.B.; Popov, K.I.

    1995-12-31

    The offered technological line includes a flotation pulp air conditioner operating on the impact-mechanical effect and two column apparatuses with a descending pulp-air flow mounted in series. The technology developed makes it possible to increase considerably the valuable component in the concentrate simultaneously with a reduction in energy consumption for the flotation process. The experience achieved with the technology showed the possibility for obtaining sulfide silver-bearing ore superconcentrates with the noble metal content 2--10 times higher than that in the concentrates obtained by the conventional technology. The same results were obtained in the process of calcium-bearing boron-silicate ore-dressing.

  12. A study of the interfacial chemistry of pyrite and coal in fine coal cleaning using flotation

    SciTech Connect

    Jiang, C.

    1993-12-31

    Surface oxidation, surface charge, and flotation properties have been systematically studied for coal, coal-pyrite and ore-pyrite. Electrochemical studies show that coal-pyrite exhibits much higher and more complex surface oxidation than ore-pyrite and its oxidation rate depends strongly on the carbon/coal content. Flotation studies indicate that pyrites have no self-induced floatability. Fuel oil significantly improves the floatability of coal and induces considerable flotation for coal-pyrite due to the hydrophobic interaction of fuel oil with the carbon/coal inclusions on the pyrite surface. Xanthate is a good collector for ore-pyrite but a poor collector for coal and coal-pyrite. The results from thermodynamic calculations, flotation and zeta potential measurements show that iron ions greatly affect the flotation of pyrite with xanthate and fuel oil. Various organic and inorganic chemicals have been examined for depressing coal-pyrite. It was found, for the first time, that sodium pyrophosphate is an effective depressant for coal-pyrite. Solution chemistry shows that pyrophosphate reacts with iron ions to form stable iron pyrophosphate complexes. Using pyrophosphate, the complete separation of pyrite from coal can be realized over a wide pH range at relatively low dosage.

  13. Electrokinetic potential of flotation pulps

    SciTech Connect

    Mis'nik, V.A.

    1988-03-01

    Studies have been done on the possibility of intensifying flotation processes by electrical treatment of flotation pulps. The electrokinetic potential is a parameter which may characterize the flotation properties of pulps. In this paper, the authors obtain calculation relationships for determining the electrokinetic potential from the results of measuring sedimentation potential. The equations obtained are used to study both sedimentationally stable pulps and sedimentationally unstable coarsely dispersed suspensions.

  14. New aspects in the theory and practice of column flotation

    SciTech Connect

    Rubinstein, J.; Badenicov, V.

    1995-12-31

    The high efficiency of column flotation allows a reduction in process time, a decrease in the number of cleaner stages and in the volume of the circulating load in the flotation circuit, and, as a result of this, an increase in consistency and reliability of operations. Unique multisectional column flotation apparatuses were developed. To attain that aim particular hydrodynamics and aeration regime is established in each section of the column, operational variables being adjusted according to the floatability of the material. Therefore in multisectional column machines, the material-apparatus feedback can be established, and process variables optimized depending on the characteristics of the floated materials. Successful operation was reported of the new generation of columns with cell volumes of 10 to 80 m{sup 3} and the height of 4--6 m in copper, molybdenum, antimony, tungsten and nickel ores and coal slurry processing at different plants. Operational experience of these cells showed their considerable design and operational advantages and verified the proposed options and relationships. The new apparatus is provided with a pneumohydraulic aerator allowing to control bubble size distribution, the service life of the aerator is not less than two years. A multilevel flotation model was developed and used to work out a technique of column design and process parameters calculation. A method of the apparatus design parameters calculation based on laboratory test results (scaling up) was worked out.

  15. Lunar ores

    NASA Astrophysics Data System (ADS)

    Gillett, S. L.

    Geochemical considerations indicate that local concentrations, referred to here as ore bodies, of lunar-deficient elements (LDEs) may exist on the moon. To illustrate this, the earth is discussed, since it exemplifies the sort of large scale chemical fractionation that a planet undergoes. Lunar geology is then reviewed, and impact cratering is discussed as a geologic process. Possible ore-forming mechanisms are then considered, noting that nearly pure bodies of anorthosite, the major source of Al, should occur. Other mechanisms considered possible are cumulate deposits in layered igneous intrusion and concentrations of rare, refractory lithophile elements in highly differentiated, silica-rich magmas.

  16. Picobubble enhanced fine coal flotation

    SciTech Connect

    Tao, Y.J.; Liu, J.T.; Yu, S.; Tao, D.

    2006-07-01

    Froth flotation is widely used in the coal industry to clean -28 mesh fine coal. A successful recovery of particles by flotation depends on efficient particle-bubble collision and attachment with minimal subsequent particle detachment from bubble. Flotation is effective in a narrow size range beyond which the flotation efficiency drops drastically. It is now known that the low flotation recovery of particles in the finest size fractions is mainly due to a low probability of bubble-particle collision while the main reason for poor coarse particle flotation recovery is the high probability of detachment. A fundamental analysis has shown that use of picobubbles can significantly improve the flotation recovery of particles in a wide range of size by increasing the probability of collision and attachment and reducing the probability of detachment. A specially designed column with a picobubble generator has been developed for enhanced recovery of fine coal particles. Picobubbles were produced based on the hydrodynamic cavitation principle. They are characterized by a size distribution that is mostly below 1 {mu}m and adhere preferentially to the hydrophobic surfaces. The presence of picobubbles increases the probability of collision and attachment and decreases the probability of detachment, thus enhancing flotation recovery. Experimental results with the Coalberg seam coal in West Virginia, U.S.A. have shown that the use of picobubbles in a 2 in. column flotation increased fine coal recovery by 10-30%, depending on the feed rate, collector dosage, and other flotation conditions. Picobubbles also acted as a secondary collector and reduced the collector dosage by one third to one half.

  17. Selective flotation of inorganic sulfides from coal

    DOEpatents

    Miller, Kenneth J. (Floreffe, PA); Wen, Wu-Wey (Murrysville, PA)

    1989-01-01

    Pyritic sulfur is removed from coal or other carbonaceous material through the use of humic acid as a coal flotation depressant. Following the removal of coarse pyrite, the carbonaceous material is blended with humic acid, a pyrite flotation collector and a frothing agent within a flotation cell to selectively float pyritic sulfur leaving clean coal as an underflow.

  18. Selective flotation of inorganic sulfides from coal

    DOEpatents

    Miller, K.J.; Wen, Wu-Wey

    1988-05-31

    Pyritic sulfur is removed from coal or other carbonaceous material through the use of humic acid as a coal flotation depressant. Following the removal of coarse pyrite, the carbonaceous material is blended with humic acid, a pyrite flotation collector and a frothing agent within a flotation cell to selectively float pyritic sulfur leaving clean coal as an underflow. 1 fig., 2 tabs.

  19. 33 CFR 183.322 - Flotation materials.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation materials. 183.322 Section 183.322 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... of 2 Horsepower or Less General § 183.322 Flotation materials. (a) Flotation materials must meet...

  20. 33 CFR 183.322 - Flotation materials.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation materials. 183.322 Section 183.322 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... of 2 Horsepower or Less General § 183.322 Flotation materials. (a) Flotation materials must meet...

  1. 33 CFR 183.322 - Flotation materials.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation materials. 183.322 Section 183.322 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... of 2 Horsepower or Less General § 183.322 Flotation materials. (a) Flotation materials must meet...

  2. 33 CFR 183.322 - Flotation materials.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation materials. 183.322 Section 183.322 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED... of 2 Horsepower or Less General § 183.322 Flotation materials. (a) Flotation materials must meet...

  3. 33 CFR 183.114 - Test of flotation materials.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats 183.114 Test of flotation materials. (a) Vapor test. The flotation...

  4. The jet flotation column control system

    SciTech Connect

    Xu Zhiqiang; Ming Shangzhi; Liu Lijian; Huangfu Jinghua; Huo Sen; Zhang Rongzeng; Yang Hongjun

    1998-12-31

    Compared with the conventional mechanical flotation column, the jet flotation column has the advantages of high selectivity of separation, low investment and production cost, low floor space requirement, low dosage of reagent, easy control; it is more suitable to process fine particles. Recently, many new types of flotation columns have been developed with new methods. Mineral Processing Dept., China University of Mining and Technology (Beijing) designed an aerated, double-jet flotation column in the lab and the industrial trial will be put into operation. One of the significant characteristics of the new type of flotation column is high selectivity of separation, fast bubble mineralization speed. As it is sensitive to various factors, a control system for flotation column has been developed to stabilize the working condition, and this set of control system has been operated in the lab experiment.

  5. Investigation on the vitrinite enrichment by flotation

    SciTech Connect

    Ren Shou Zheng; Wang Lu Ji; Zhu Shu Quan; Wang Zuna; Yang Su Qing

    1995-12-31

    The difference in surface hydrophobicity and zeta potential for vitrinite and fusinite and the influence to flotation behavior were analyzed in this investigation. A flotation method was adopted to enrich the vitrinite. The flotation test results for three subbituminous coals indicate that the vitrinite content could be improved to 80% from 65% under the optimum condition of using a cationic surfactant, while ash content in the product could still be guaranteed.

  6. Comparison of column flotation cells

    SciTech Connect

    Honaker, R.Q.; Mohanty, M.K.; Ho, K.

    1995-08-01

    Six commercial column flotation technologies, i.e., Canadian, Flotaire, Jameson, Microcel, Packed-Column, and Turbo-air, were tested for the treatment of Illinois Basin fine coal and the results from each column compared based on separation performance and throughout capacity. The separation performance achieved by each cell approached and, in some cases, exceeded the ultimate performance predicted by release analysis. A comparison of the test results indicates differences in the selectivity obtained by each flotation column on the basis of both ash and sulfur rejection. This finding may be due to variations in cell hydrodynamics and the ability to support a deep froth phase among the different column cells. In addition, throughput capacity of each cell was found to differ, apparently due to the differences in the bubble-particle attachment environment, bubble size, and bubble population. Variations in the operating characteristics, such as reagent additions, aeration rate and wash water rate, were also noted and summarized in this publication.

  7. Sewage treatment-flotation apparatus

    SciTech Connect

    Hines, D.A.; Jones, R.T.; Roesler, F.C.

    1981-03-03

    Solids-liquid separation, wherein a solids-liquid mixture containing dissolved oxygen-containing gas is circulated around a circulatory system comprising a downcomer and a riser, part of the mixture in the riser being introduced into a flotation chamber in which the hydrostatic pressure gradually decreases as the mixture flows upwards, with consequent release from solution of gas bubbles which carry solid particles to the top of the mixture.

  8. A dynamics model for fine coal flotation

    SciTech Connect

    Youjun, T.; Maixi, L.

    1999-07-01

    Through a large amount of experiments, this article studied the effect of the entrapment of water flow on the fine coal flotation during the flotation, and also investigated the relation between the constant of water flotation rate and different operation variables, and resulted in its equation. The water-recycling model is determined, and finally, the dynamics model on relation between the recovery of fine particle and the water recovery in concentration is established. The equation about ash of fine clean coal in any flotation time is derived by introduction of de-ashed coefficient.

  9. Flotation properties of some monocyclic aromatic compounds

    SciTech Connect

    Shreider, E.M.; Kontorovich, V.E.; Galanov, M.E.; Trachik, T.L.; Lagutina, L.V.

    1981-01-01

    The flotation properties of aromatic compounds with polar substitutes in the ring have not been adequately studied. For instance, we were the first to examine bromobenzene, nitrobenzene, N-ethylaniline and anisole as possible flotation reagents. Their flotation properties were determined in a Mekhanobr laboratory flotation machine of chamber capacity 1.5 liters, with an impeller speed of 1800 rpm. The tests were carried out on thickened slurry from radial thickeners. In addition, we have tested aromatic amines (o- and p-nitroanalines, p-anisidine, o- and p-toluidines). They were used for the flotation of raw charge (<0.5 mm size fraction). The raw material was averaged before flotation; the solids content of the pulp was 200 g/liter in both cases. Of the aromatic compounds with polar substituents examined, N-ethyl-aniline possesses the optimum flotation properties. The flotation indices of o-isomers are directly related to their dipole moments. For p-isomers, a direct correlation exists between flotation parameters and basicity.

  10. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats 183.112 Flotation material and air chambers. (a)...

  11. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats 183.112 Flotation material and air chambers. (a)...

  12. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats 183.112 Flotation material and air chambers. (a)...

  13. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats 183.112 Flotation material and air chambers. (a)...

  14. Selective flotation of phosphate minerals with hydroxamate collectors

    DOEpatents

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

    2002-01-01

    A method is disclosed for separating phosphate minerals from a mineral mixture, particularly from high-dolomite containing phosphate ores. The method involves conditioning the mineral mixture by contacting in an aqueous in environment with a collector in an amount sufficient for promoting flotation of phosphate minerals. The collector is a hydroxamate compound of the formula; ##STR1## wherein R is generally hydrophobic and chosen such that the collector has solubility or dispersion properties it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms. M is a cation, typically hydrogen, an alkali metal or an alkaline earth metal. Preferably, the collector also comprises an alcohol of the formula, R'--OH wherein R' is generally hydrophobic and chosen such that the collector has solubility or dispersion properties so that it can be distributed in the mineral mixture, typically an alkyl, aryl, or alkylaryl group having 6 to 18 carbon atoms.

  15. N-(6-(hydroxyamino)-6-oxohexyl) decanamide collector: Flotation performance and adsorption mechanism to diaspore

    NASA Astrophysics Data System (ADS)

    Deng, Lanqing; Wang, Shuai; Zhong, Hong; Liu, Guangyi

    2015-08-01

    In this paper, a novel surfactant, N-(6-(hydroxyamino)-6-oxohexyl)decanamide (NHOD) was synthesized and used as a collector for flotation separation of diaspore and aluminosilicate minerals. The adsorption mechanism of NHOD onto diaspore was also investigated by FTIR spectra, zeta potential measurement and XPS. The flotation results demonstrated that NHOD exhibited superior collecting power to diaspore and selectivity against kaolinite and illite and could effectively realize flotation recovery of diaspore from bauxite ores contained aluminosilicate minerals under neutral conditions. The results of XPS, FTIR spectra and zeta potential illustrated that at around pH 7.0, NHOD might chemisorb on diaspore surfaces through Alsbnd O coordination bonds formed by binding its sbnd C(dbnd O)NHOH or sbnd C(dbnd O)NHsbnd chelate groups with aluminum atoms on diaspore surfaces. NHOD's unique properties, such as characteristic bond patterns onto diaspore surfaces, two hydrophobic groups, and intermolecular hydrogen bonds between neighboring NHOD molecules coated on diaspore surfaces, rendered it to be a superior flotation collector for diaspore.

  16. New influence factor inducing difficulty in selective flotation separation of Cu-Zn mixed sulfide minerals

    NASA Astrophysics Data System (ADS)

    Deng, Jiu-shuai; Mao, Ying-bo; Wen, Shu-ming; Liu, Jian; Xian, Yong-jun; Feng, Qi-cheng

    2015-02-01

    Selective flotation separation of Cu-Zn mixed sulfides has been proven to be difficult. Thus far, researchers have found no satisfactory way to separate Cu-Zn mixed sulfides by selective flotation, mainly because of the complex surface and interface interaction mechanisms in the flotation solution. Undesired activation occurs between copper ions and the sphalerite surfaces. In addition to recycled water and mineral dissolution, ancient fluids in the minerals are observed to be a new source of metal ions. In this study, significant amounts of ancient fluids were found to exist in Cu-Zn sulfide and gangue minerals, mostly as gas-liquid fluid inclusions. The concentration of copper ions released from the ancient fluids reached 1.02 × 10-6 mol/L, whereas, in the cases of sphalerite and quartz, this concentration was 0.62 × 10-6 mol/L and 0.44 × 10-6 mol/L, respectively. As a result, the ancient fluid is a significant source of copper ions compared to mineral dissolution under the same experimental conditions, which promotes the unwanted activation of sphalerite. Therefore, the ancient fluid is considered to be a new factor that affects the selective flotation separation of Cu-Zn mixed sulfide ores.

  17. 33 CFR 183.322 - Flotation materials.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation materials. 183.322 Section 183.322 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General ...

  18. 33 CFR 183.302 - Flotation requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation requirements. 183.302 Section 183.302 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General...

  19. 33 CFR 183.302 - Flotation requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation requirements. 183.302 Section 183.302 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General...

  20. 33 CFR 183.302 - Flotation requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation requirements. 183.302 Section 183.302 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General...

  1. 33 CFR 183.302 - Flotation requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation requirements. 183.302 Section 183.302 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General...

  2. 33 CFR 183.302 - Flotation requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation requirements. 183.302 Section 183.302 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or Less General...

  3. 21 CFR 890.3175 - Flotation cushion.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Flotation cushion. 890.3175 Section 890.3175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion....

  4. 21 CFR 890.3175 - Flotation cushion.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Flotation cushion. 890.3175 Section 890.3175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion....

  5. 21 CFR 890.3175 - Flotation cushion.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Flotation cushion. 890.3175 Section 890.3175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion....

  6. 21 CFR 890.3175 - Flotation cushion.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Flotation cushion. 890.3175 Section 890.3175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion....

  7. 21 CFR 890.3175 - Flotation cushion.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Flotation cushion. 890.3175 Section 890.3175 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Prosthetic Devices § 890.3175 Flotation cushion....

  8. Surface chemical problems in coal flotation

    NASA Astrophysics Data System (ADS)

    Taylor, S. R.; Miller, K. J.; Deurbrouck, A. W.

    1981-02-01

    As the use of coal increases and more fine material is produced by mining and processing, the need for improved methods of coal beneficiation increases. While flotation techniques can help meet these needs, the technique is beset with many problems. These problems involve surface chemical and interfacial properties of the coal-mineral-water slurry systems used in coal flotation. The problems associated with coal flotation include non-selectivity, inefficient reagent utilization, and excessive variablity of results. These problems can be broadely classified as a lack of predictability. The present knowledge of coal flotation is not sufficient, in terms of surface chemical parameters, to allow prediction of the flotation response of a given coal. In this paper, some of the surface chemical properties of coal and coal minerals that need to be defined will be discussed in terms of the problems noted above and their impact on coal cleaning.

  9. Hydrophobic flocculation flotation for beneficiating fine coal and minerals

    SciTech Connect

    Song, S.; Valdivieso, A.L.

    1998-06-01

    It is shown that hydrophobic flocculation flotation (HFF) is an effective process to treat finely ground ores and slimes so as to concentrate coal and mineral values at a fine size range. The process is based on first dispersing the fine particles suspension, followed by flocculation of fine mineral values or coal in the form of hydrophobic surfaces either induced by specifically adsorbed surfactants or from nature at the conditioning of the slurry with the shear field of sufficient magnitude. The flocculation is intensified by the addition of a small amount of nonpolar oil. finely ground coals, ilmenite slimes, and gold finely disseminated in a slag have been treated by this process. Results are presented indicating that cleaned coal with low ash and sulfur remaining and high Btu recovery can be obtained, and the refractory ores of ilmenite slimes and fine gold-bearing slag can be reasonably concentrated, leading to better beneficiation results than other separation techniques. In addition, the main operating parameters affecting the HFF process are discussed.

  10. Great Barrier Reef

    Atmospheric Science Data Center

    2013-04-16

    ... reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by ... visible in this image is Whitsunday Island, with smaller islands and reefs extending southeast, parallel to the coast. These include ...

  11. Flotation control -- A multivariable stabilizer

    SciTech Connect

    Schubert, J.H.; Henning, R.G.D.; Hulbert, D.G.; Craig, I.K.

    1995-12-31

    This paper presents a stabilizing controller for flotation plants which uses a quasi-multivariable technique. The controller monitors all the levels in the plant, and by anticipating interactions between various parts of the plant, is able to stabilize the plant far more successfully than the normal plant control. Once stabilizing control has been achieved, optimization of the process becomes easier and more sustainable. An estimate of the improvement in metallurgical performance is made and a singular value analysis was conducted to verify that the multivariable algorithm will theoretically control better than a collection of individual PID loops. Metallurgical results are presented to show that the improvements are attainable in practice. Control by the Mintek algorithm was alternated with normal plant control, to show that the improvements are statistically significant.

  12. Effect of particle fineness on the finely disseminated iron ore for beneficiation

    NASA Astrophysics Data System (ADS)

    Qiu, T. S.; Zhang, W. X.; Fang, X. H.; Gao, G. K.

    2013-06-01

    This paper focused on Oolitic hematite ore which consists of extremely unequal disseminated particles that are fine-grained and easy to become muddy, It presents the effect of particle fineness, roasting temperature and roasting time and other variables on the beneficiation of this ore. The effect of particle fineness on the concentrate quality was also studied after magnetic roasting, the so-called process of "magnetic roasting-stage grinding-low intensity magnetic separation-cationic reverse flotation" was adopted to treat the raw ore under various experimental conditions including particle fineness, roasting temperature and roasting time, etc. it is found the concentrate grade of TFe of raw ore can be increased from 48.32%(original) to 61.30% at a recovery rate of 80.73%. Results show that the effect of particle fineness on mineral processing indexes is significant.

  13. Plant practices in fine coal column flotation

    SciTech Connect

    Davis, V.L. Jr.; Bethell, P.J.; Stanley, F.L.; Luttrell, G.H.

    1995-10-01

    Five 3 m (10 ft) diameter Microcel{trademark} flotation columns were installed at Clinchfield Coal Company`s Middle Fork preparation facility in order to reduce product ash and increase recovery and plant capacity. The Middle Fork facility is utilized for the recovery of fine coal from a feed stream that consists primarily of 1.5 mm x 0 material. The columns replaced conventional flotation cells for the treatment of the minus 150 {micro}m fraction while spirals are used to upgrade the plus 150 {micro}m material in the plant feed. The addition of the column flotation circuit resulted in an increase in plant capacity in excess of 20 percent while reducing the flotation product ash content by approximately 7 percentage points. Flotation circuit combustible recovery wa increased by 17 percentage points. This paper discusses circuit design, commissioning, and sparging system design. Circuit instrumentation, level control, reagent system control, performance comparisons with conventional flotation, and general operating procedures are also discussed.

  14. Beneficiation of rare earth minerals from Bokan Mountain - Dotson Ridge ore

    NASA Astrophysics Data System (ADS)

    Narantsetseg, Purevbaatar

    The purpose of this research work was to study the beneficiation of rare earth ore of the Bokan Mountain - Dotson Ridge deposit, located near Ketchikan, Alaska. Rare earth element (REE) composite ore samples from the Bokan Mountain - Dotson Ridge deposit were tested using gravity concentration, magnetic separation, flotation, and leaching techniques to separate the REE. The composite ore sample was a product of a preliminary x-ray sorting process. Qualitative electron microprobe analysis of the ore showed that most of the REE minerals in the ore were silicate minerals. Since the electron microprobe analysis samples were coated with carbon during sample preparation, the carbon element was inactivated for analysis. Because of this, carbonate compounds of minerals' particles could not be detected. 95% of the REE mineral particles appear to be smaller than about 10 microm in size (about 100 microm2 in area). For the gravity concentration, light rare earth elements (LREE) and heavy rare earth elements' (HREE) individual elemental recovery values were in the ranges of 49.6-52.8% and 46.3-48.8%, respectively, at 25% of mass yield. In order to separate a larger amount of the REE, a wet high intensity magnetic separation (WHIMS) test was carried out on tailings of the gravity concentration tests. The HREE individual elemental recovery values ranged from 56.3-63.1% at 37% mass yield, while LREE individual elemental recovery values were in the 57.9% - 59.1% range. For the combined gravity and magnetic separation processes, the net individual elemental recovery values of the LREE and the HREE were in the range of 79.6-80.5% and 76.5-80.9%, respectively. The combined mass yield of the gravity and magnetic separation processes was 53%. Direct leaching tests conducted on the composite ground ore feed yielded high individual elemental recovery values of 90-92% of the LREE. The HREE individual elemental recovery values ranged from 56.5-87.3%. In the leaching, 20% HCl was used in the 1st and 2nd stages with a duration of 2 hrs in each stage at 90°C. The solid percentage of the leach slurry was 20% w/w. The composite ground ore sample was tested in conventional flotation using a 2.0 L capacity Denver cell. In the flotation, 0.05 kg/tonne of Cytec Aero 6493 collector, 0.05 kg/tonne of Cytec Aero Froth 88, and 0.1 kg/tonne of sodium metasilicate as a depressant were used. Pulp pH was set around 9. Results showed individual elemental recovery values in the range of 44.6-50.4% for the LREE. The HREE individual elemental recovery values ranged from 27.9-44.5%. The mass yield of the flotation was 23%. The flotation recoveries reported here are significantly lower than what was achieved previously. For the Leach after flotation process, leaching was conducted on the first concentrate of flotation. Individual elemental recovery values of the LREE and HREE were 94.7-96.5% and 61.1-90.5%, respectively. The concentrate was leached using 20% HCl in both the 1st and 2nd stages, with a duration of 2 hrs in each stage at 90°C. Flotation/Leach process net recoveries of LREE by individual elemental values ranged from 42.2-48.5%. HREE net recoveries by individual elemental values ranged from 17.1-41.4%.

  15. Flotation selectivity of novel alkyl dicarboxylate reagents for apatite-calcite separation.

    PubMed

    Karlkvist, Tommy; Patra, Anuttam; Rao, Kota Hanumantha; Bordes, Romain; Holmberg, Krister

    2015-05-01

    The investigation aims to demonstrate the conceptual thoughts behind developing mineral specific reagents for use in flotation of calcium containing ores. For this purpose, a series of dicarboxylate-based surfactants with varying distance between the carboxylate groups (one, two or three methylene groups) was synthesized. A surfactant with the same alkyl chain length but with only one carboxylate group was also synthesized and evaluated. The adsorption behavior of these new reagents on pure apatite and pure calcite surfaces was studied using Hallimond tube flotation, FTIR and ζ potential measurements. The relation between the adsorption behavior of a given surfactant at a specific mineral surface and its molecular structure over a range of concentrations and pH values, as well as the region of maximum recovery, was established. It was found that one of the reagents, with a specific distance between the carboxylate groups, was much more selective for a particular mineral surface than the other homologues. For example, out of the four compounds synthesized, only the one where the carboxylate groups were separated by a single methylene group floated apatite but not calcite, whereas calcite was efficiently floated with the monocarboxylic reagent, but not with the other reagents synthesized. This selective adsorption of a given surfactant to a particular mineral surface relative to other mineral surfaces as evidenced in the flotation studies was substantiated by ζ potential and infra-red spectroscopy data. PMID:25596367

  16. Great Barrier Reef, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1990-01-01

    This detailed view of the Great Barrier Reef, Queensland, Australia (19.5S, 149.5E) shows several small patch reefs within the overall reef system. The Great Barrier Reef, largest in the world, comprises thousands of individual reefs of great variety and are closely monitored by marine ecologists. These reefs are about 6000 years old and sit on top of much older reefs. The most rapid coral growth occurs on the landward side of the reefs.

  17. Shale-oil-recovery systems incorporating ore beneficiation. Final report.

    SciTech Connect

    Weiss, M.A.; Klumpar, I.V.; Peterson, C.R.; Ring, T.A.

    1982-10-01

    This study analyzed the recovery of oil from oil shale by use of proposed systems which incorporate beneficiation of the shale ore (that is concentration of the kerogen before the oil-recovery step). The objective was to identify systems which could be more attractive than conventional surface retorting of ore. No experimental work was carried out. The systems analyzed consisted of beneficiation methods which could increase kerogen concentrations by at least four-fold. Potentially attractive low-enrichment methods such as density separation were not examined. The technical alternatives considered were bounded by the secondary crusher as input and raw shale oil as output. A sequence of ball milling, froth flotation, and retorting concentrate is not attractive for Western shales compared to conventional ore retorting; transporting the concentrate to another location for retorting reduces air emissions in the ore region but cost reduction is questionable. The high capital and energy cost s results largely from the ball milling step which is very inefficient. Major improvements in comminution seem achievable through research and such improvements, plus confirmation of other assumptions, could make high-enrichment beneficiation competitive with conventional processing. 27 figures, 23 tables.

  18. FLOCCULATION-FLOTATION AIDS FOR TREATMENT OF COMBINED SEWER OVERFLOWS

    EPA Science Inventory

    The objectives of this study were to investigate the flocculation/flotation characteristics of combined sewer overflow through laboratory and field testing. The concept involves the introduction of chemicals and buoyant flotation aids into the overflow and the subsequent cofloccu...

  19. Dissolved air flotation and me.

    PubMed

    Edzwald, James K

    2010-04-01

    This paper is mainly a critical review of the literature and an assessment of what we know about dissolved air flotation (DAF). A few remarks are made at the outset about the author's personal journey in DAF research, his start and its progression. DAF has been used for several decades in drinking water treatment as an alternative clarification method to sedimentation. DAF is particularly effective in treating reservoir water supplies; those supplies containing algae, natural color or natural organic matter; and those with low mineral turbidity. It is more efficient than sedimentation in removing turbidity and particles for these type supplies. Furthermore, it is more efficient in removing Giardia cysts and Cryptosporidium oocysts. In the last 20 years, fundamental models were developed that provide a basis for understanding the process, optimizing it, and integrating it into water treatment plants. The theories were tested through laboratory and pilot-plant studies. Consequently, there have been trends in which DAF pretreatment has been optimized resulting in better coagulation and a decrease in the size of flocculation tanks. In addition, the hydraulic loading rates have increased reducing the size of DAF processes. While DAF has been used mainly in conventional type water plants, there is now interest in the technology as a pretreatment step in ultrafiltration membrane plants and in desalination reverse osmosis plants. PMID:20096437

  20. 21 CFR 880.5550 - Alternating pressure air flotation mattress.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Alternating pressure air flotation mattress. 880... Personal Use Therapeutic Devices 880.5550 Alternating pressure air flotation mattress. (a) Identification. An alternating pressure air flotation mattress is a device intended for medical purposes...

  1. 21 CFR 880.5150 - Nonpowered flotation therapy mattress.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Nonpowered flotation therapy mattress. 880.5150... Therapeutic Devices § 880.5150 Nonpowered flotation therapy mattress. (a) Identification. A nonpowered flotation therapy mattress is a mattress intended for medical purposes which contains air, fluid, or...

  2. 21 CFR 880.5150 - Nonpowered flotation therapy mattress.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Nonpowered flotation therapy mattress. 880.5150... Therapeutic Devices § 880.5150 Nonpowered flotation therapy mattress. (a) Identification. A nonpowered flotation therapy mattress is a mattress intended for medical purposes which contains air, fluid, or...

  3. 21 CFR 880.5150 - Nonpowered flotation therapy mattress.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Nonpowered flotation therapy mattress. 880.5150... Therapeutic Devices § 880.5150 Nonpowered flotation therapy mattress. (a) Identification. A nonpowered flotation therapy mattress is a mattress intended for medical purposes which contains air, fluid, or...

  4. 33 CFR 175.15 - Personal flotation devices required.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Personal flotation devices... SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices 175.15 Personal flotation devices required. Except as provided in 175.17 and 175.25: (a) No person may use a...

  5. 33 CFR 175.15 - Personal flotation devices required.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Personal flotation devices required. 175.15 Section 175.15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices 175.15 Personal flotation devices required. Except as provided in...

  6. Frothing in flotation. Volume 2: Recent advances in coal processing

    SciTech Connect

    Laskowski, J.S.; Woodburn, E.T.

    1998-11-01

    This volume summarizes the achievements on various aspects of flotation froth properties and behavior, and relationship between froth appearance and flotation performance. Flotation kinetics involves a number of mass transfer processes with some of them being critically determined by the behavior of froth. Since froth is complex, and controlled experimentation is difficult, the froth phase was, until recently, either ignored or treated entirely empirically. With wide applications of flotation columns, the behavior of the froth is now often recognized as being dominant in determining flotation performance, and the research in this area is one of the most actively pursued. Contents include: Frothers and frothing; Effect of particle and bubble size on flotation kinetics; Water content and distribution in flotation froths; Mechanisms operating in flotation froths; Characterization of flotation froth; Simultaneous determination of collection zone rate constant and froth zone recovery factor; Modelling of froth dynamics with implications for feed-back control; The interrelationship between flotation variables and froth appearance; Froth image analysis in a flotation control system; Kinetic flotation modelling using froth imaging data; and Dependence of froth behavior on galvanic interactions.

  7. 33 CFR 175.15 - Personal flotation devices required.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Personal flotation devices required. 175.15 Section 175.15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices 175.15 Personal flotation devices required. Except as provided in...

  8. 33 CFR 175.15 - Personal flotation devices required.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Personal flotation devices required. 175.15 Section 175.15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices 175.15 Personal flotation devices required. Except as provided in...

  9. 33 CFR 175.15 - Personal flotation devices required.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Personal flotation devices required. 175.15 Section 175.15 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY EQUIPMENT REQUIREMENTS Personal Flotation Devices 175.15 Personal flotation devices required. Except as provided in...

  10. Physically absorbable reagents-collectors in elementary flotation

    SciTech Connect

    S.A. Kondrat'ev; I.G. Bochkarev

    2007-09-15

    Based on the reviewed researches held at the Institute of Mining, Siberian Branch, Russian Academy of Sciences, the effect of physically absorbable reagents-collectors on formation of a flotation complex and its stability in turbulent pulp flows in flotation machines of basic types is considered. The basic requirements for physically absorbable reagents-collectors at different flotation stages are established.

  11. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Personal flotation device lights. 25.25-13 Section 25.25... Preservers and Other Lifesaving Equipment § 25.25-13 Personal flotation device lights. (a) This section... device intended to be worn, and each buoyant vest must have a personal flotation device light that...

  12. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Personal flotation device lights. 25.25-13 Section 25.25... Preservers and Other Lifesaving Equipment § 25.25-13 Personal flotation device lights. (a) This section... device intended to be worn, and each buoyant vest must have a personal flotation device light that...

  13. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Personal flotation device lights. 25.25-13 Section 25.25... Preservers and Other Lifesaving Equipment § 25.25-13 Personal flotation device lights. (a) This section... device intended to be worn, and each buoyant vest must have a personal flotation device light that...

  14. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Personal flotation device lights. 25.25-13 Section 25.25... Preservers and Other Lifesaving Equipment § 25.25-13 Personal flotation device lights. (a) This section... device intended to be worn, and each buoyant vest must have a personal flotation device light that...

  15. 46 CFR 25.25-13 - Personal flotation device lights.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Personal flotation device lights. 25.25-13 Section 25.25... Preservers and Other Lifesaving Equipment § 25.25-13 Personal flotation device lights. (a) This section... device intended to be worn, and each buoyant vest must have a personal flotation device light that...

  16. Dissolved mineral species precipitation during coal flotation

    SciTech Connect

    Somasundaran, P.; Liu, D.

    1995-12-31

    Beneficiation by froth flotation, which exploits the difference in surface properties of minerals, has been a promising method for coal cleaning.However, dissolved mineral species present in coal flotation systems can interact with particles and other species leading to drastic effects on flotation. Particularly, precipitation or adsorption of such species on the particles can alter their surface properties and thus influence the efficiency of coal cleaning. In this work, the bulk and surface precipitation of the dissolved mineral species present in Pittsburgh No. 8 coal was investigated under controlled experimental conditions. Changes in the surface properties of coal due to the precipitation were monitored by following zeta potential. Solution potential data were used to elucidate the mechanism of the precipitation. The effect of the precipitation of the dissolved species on the floatability of coal was found to be marked.

  17. Flotation of cadmium-loaded biomass

    SciTech Connect

    Matis, K.A.; Zouboulis, A.I. . Chemical Technology Div.)

    1994-07-01

    Biosorption of heavy metal ions such as Cd[sup 2+] by dead biomass has been recognized as a potential alternative to existing removal technologies applied to wastewater treatment. Two bacterial strains were studied in the laboratory, Streptomyces griseus and S. clavuligerus, an industrial by-product. Both washed and unwashed samples were examined. Foam flotation is proposed in this work as the separation stage following biosorption. Effective biomass separation was conducted in the presence of a frother, ethanol. The pH of the solution was a crucial parameter for flotation and also for metal binding. Other basic parameters of flotation examined were the initial cadmium concentration in the dilute aqueous solution and the quantity of biomass used. A study of [zeta]-potential measurements of the actinomycetes was carried out under the conditions used in the separation; surface tension was also measured. These provided useful information on the process.

  18. Journey to the Reef

    ERIC Educational Resources Information Center

    Bryson, Linda

    2010-01-01

    Despite their experiences with a cartoon sponge, most elementary students know little about the diverse inhabitants of coral reefs. Therefore, with vivid photography and video, diverse coral reef inhabitants were brought to life for the author's fifth-grade students. Students shared their knowledge in language arts and even explored coral reefs in…

  19. Journey to the Reef

    ERIC Educational Resources Information Center

    Bryson, Linda

    2010-01-01

    Despite their experiences with a cartoon sponge, most elementary students know little about the diverse inhabitants of coral reefs. Therefore, with vivid photography and video, diverse coral reef inhabitants were brought to life for the author's fifth-grade students. Students shared their knowledge in language arts and even explored coral reefs in

  20. Effect of microwave radiation on coal flotation

    SciTech Connect

    Ozbayoglu, G.; Depci, T.; Ataman, N.

    2009-07-01

    Most low-rank coals are high in moisture and acid functional groups, therefore showing poor floatability. Drying, which removes the water molecules trapped in the pores and adsorbed at the surface of coal, decreases the hydrophilic character and improves the floatability. Microwave heating, whose simplest application is drying, was applied at 0.9 kW power level for 60 sec exposure time in the experiments to decrease the moisture content of coal in order to enhance the hydrophobicity. The flotation tests of microwave-treated coal by using heptanol and octanol lead to a higher flotation yield and ash removal than original coal.

  1. 26. NORTHERN VIEW OF ORE YARD WITH ORE BRIDGES IN ...

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

    26. NORTHERN VIEW OF ORE YARD WITH ORE BRIDGES IN THE BACKGROUND. BLAST FURNACES ALONG THE RIGHT SIDE. (Martin Stupich) - U.S. Steel Duquesne Works, Blast Furnace Plant, Along Monongahela River, Duquesne, Allegheny County, PA

  2. Introduction to ore geology

    SciTech Connect

    Evans, A.M.

    1987-01-01

    This textbook on ore geology is for second and third year undergraduates and closely parallels the undergraduate course given in this subject at England's University of Leicester. The volume covers three major areas: (1) principles of ore geology, (2) examples of the most important types of ore deposits, and (3) mineralization in space and time. Many chapters have been thoroughly revised for this edition and a chapter on diamonds has been added. Chapters on greisen and pegmatite have also been added, the former in response to the changing situation in tin mining following the recent tin crisis, and the latter in response to suggestions from geologists in a number of overseas countries. Some chapters have been considerably expanded and new sections added, including disseminated gold deposits and unconformity-associated uranium deposits. The author also expands on the importance of viewing mineral deposits from an economic standpoint.

  3. A novel multistage kinetic modeling of flotation for wastewater treatment.

    PubMed

    Ksenofontov, B S; Ivanov, M V

    2013-01-01

    This study develops a new model for description of flotation kinetics. It defines flotation as a process that consists of several stages: separated air bubbles and particles, air bubbles and particles forming an aggregate, aggregate rising to the froth layer. This description significantly differs from known models, which are much simplified. The multistage model gives a novel in-depth description and considers different aspects of flotation, i.e. aggregate formation, which is critically important for flotation to take place. Experimental approval of the new model resulted in its accuracy. The model is to be used for a description of kinetics of all flotation processes in wastewater treatment. It helps in accurate design of flotation treatment plants and may be used for further research of the flotation process. PMID:23985510

  4. Removal of molybdate and arsenate from aqueous solutions by flotation

    SciTech Connect

    Zhao, Y.; Zouboulis, A.I.; Matis, K.A.

    1996-03-01

    Ion flotation and adsorbing colloid flotation have been studied in this paper for the effective removal of molybdenum(VI) and arsenic(V) from dilute aqueous solutions. These different flotation methods were also compared. Ion flotation using a cationic surfactant (dodecylamine) as collector, as well as adsorbing colloid flotation using ferric hydroxide as coprecipitant (or sorbent) and an anionic surfactant (sodium dodecyl sulfate) as collector were examined. Laboratory-scale experiments were conducted in order to assess the effects of the following parameters of the efficiency of the process: pH value, dosages of chemical reagents, initial concentrations of arsenic and molybdenum, and the presence of foreign anions, such as Cl{sup -} and SO{sup 2}{sub 4}{sup -}. In practical applications, ion flotation or adsorbing colloid flotation may be selected according to the concentration of arsenic, molybdenum, and also the initial [Mo]/[As] molar ratios in solution.

  5. 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

  6. 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

  7. 77 FR 19937 - Inflatable Personal Flotation Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-04-03

    ... Personal Flotation Devices'' in the Federal Register. 76 FR 17561. We received three submissions in... notice of withdrawal. 76 FR 56294. On September 29, 2011, the Coast Guard issued a notice of proposed... an industry standard proposed for incorporation by reference. 76 FR 60405. The NPRM also...

  8. 76 FR 56294 - Inflatable Personal Flotation Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-13

    ... issues in a notice of proposed rulemaking. DATES: The direct final rule published March 30, 2011, (76 FR... rule entitled ``Inflatable Personal Flotation Devices'' in the Federal Register (76 FR 17561). That..., or why it would be ineffective or unacceptable without a change (76 FR 17563). This...

  9. Coal desulfurization in flotation by electrochemical control

    SciTech Connect

    Hong, Z.; Jianguo, Y.; Yanchun, S.; Zeshen, O.; Yaomin, Z.

    1999-07-01

    This paper discussed the flotation process in coal desulfurization enhanced by modifying the coal and pyrite surface electrochemically. By controlling the redox potential of pulp, the floatability of pyrite could be depressed and that of coal particles could be consolidated. This resulted in improving coal desulfurization.

  10. Plagioclase flotation and lunar crust formation

    NASA Technical Reports Server (NTRS)

    Walker, D.; Hays, J. F.

    1977-01-01

    Anorthitic plagioclase floats in liquids parental to the lunar highlands crust. The plagioclase enrichment that is characteristic of lunar highlands rocks can be the result of plagioclase flotation. Such rocks would form a gravitationally stable upper crust on their parental magma.

  11. 76 FR 60405 - Inflatable Personal Flotation Devices

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-09-29

    ... addressing the population for which inflatable recreational PFDs are approved (76 FR 17561). As discussed... Act notice regarding our public dockets in the January 17, 2008 issue of the Federal Register (73 FR... Flotation Devices'' in the Federal Register (76 FR 17561). The Coast Guard received three submissions...

  12. Benzene stripping in a flotation unit

    SciTech Connect

    Hillquist, D.; Litchfield, J.; Willet, S.; Whiteford, R.

    1994-12-31

    An induced gas flotation unit is used as a combination stripping/flotation vessel with fuel gas as the stripping/flotation medium. The gas bubbles simultaneously float the oils and solids, and strip out and recover the benzene and other volatile components from wastewater and from the floated oils and solids. The effluent stripping gas is then either used as fuel gas, or recycled to the process for product recovery. The induced gas flotation stripper, IGFS, is self-cleaning and normally experiences no sludge build up or fouling. The unit requires a minimum of operator attention and maintenance. It is sealed to eliminate emissions, has a high stripping efficiency, and has a significantly wider operating range than conventional strippers. The unit does not experience the biological fouling and disposal problems of air strippers, or the fouling and higher capital and operating costs of steam strippers. The IGFS unit was installed at the BF Goodrich ethylene plant in Calvert City in 1991. The unit was designed to treat a combined stream consisting of quench water, neutralized spent caustic, and a number of intermittent smaller oily water streams. The unit is operating effectively in stripping the benzene to levels below the NESHAP requirements. The average benzene removal efficiency is above 97%. Operating data indicate that the benzene removal efficiency can be further enhanced by increasing temperature, increasing stripping flow, reducing oil emulsions in the influent and eliminating dilution from recycled water. This paper presents performance and operating experience of the IGFS unit.

  13. Flocculation of coal flotation refuse with polyethyleneoxide

    SciTech Connect

    Baichenko, A.A.

    1982-01-01

    The adsorption of high MW polyethylene oxide by negatively charged particles of flotation refuse from a coal washing plant and its effect on refuse flocculation have been investigated. A close correlation was demonstrated between the quantity of adsorbed polymer per unit of particle surface, the change in the particle zeta potential, and the degree of clarification of the suspension.

  14. Dispersion characteristics in column flotation of fine coal

    SciTech Connect

    Peng, F.F.; Lili, L.

    1995-10-01

    The dispersion model of nonideal flow was applied to describe the hydrodynamic state within the flotation column. Residence time distribution (RTD) data of a laboratory flotation column were measured to determine the parameters of the model. The effects of operating variables and column geometry on the Peclet number which reflects the extent of axial dispersion were investigated and a semi-empirical expression of Pe was formulated. The dispersion model was validated for the column flotation of ultrafines coal. Under the conditions of sufficient aeration rate and frother addition, a good agreement between the measured recoveries and predicted data was obtained. The dispersion model with first-order flotation rate process of the flotation column developed in this study is useful in predicting the collection zone recovery of fine coal, and for the flotation column scale-up.

  15. Quantitative property-property relationship (QPPR) approach in predicting flotation efficiency of chelating agents as mineral collectors.

    PubMed

    Natarajan, R; Nirdosh, I; Venuvanalingam, P; Ramalingam, M

    2002-07-01

    The QPPR approach has been used to model cupferrons as mineral collectors. Separation efficiencies (Es) of these chelating agents have been correlated with property parameters namely, log P, log Koc, substituent-constant sigma, Mullikan and ESP derived charges using multiple regression analysis. Es of substituted-cupferrons in the flotation of a uranium ore could be predicted within experimental error either by log P or log Koc and an electronic parameter. However, when a halo, methoxy or phenyl substituent was in para to the chelating group, experimental Es was greater than the predicted values. Inclusion of a Boolean type indicative parameter improved significantly the predictability power. This approach has been extended to 2-aminothiophenols that were used to float a zinc ore and the correlations were found to be reasonably good. PMID:12442767

  16. Flotation of marine microalgae: effect of algal hydrophobicity.

    PubMed

    Garg, Sourabh; Li, Yan; Wang, Liguang; Schenk, Peer M

    2012-10-01

    This study aims to understand the underlying reasons for the poor flotation response of marine microalgae. The flotation performance and hydrophobicity of a freshwater microalga (Chlorella sp. BR2) were compared to those of a marine microalga (Tetraselmis sp. M8) at different salinities in the presence of a cationic collector, tetradecyl trimethylammonium bromide. It was found that microalgal hydrophobicity played a more important role than salinity in determining the flotation performance. PMID:22858117

  17. The industrial practice and development of flotation column in China

    SciTech Connect

    Liu Jiongtian; Zhang Shuangquan

    1997-12-31

    This paper reviewed the developing course of the flotation column since the 1960`s in China. Based on the practical data from several coal preparation plants, two types of flotation columns (the pressure aerated column and the jetting-cyclone column) were compared by their operation, performance and the reasons why they succeeded in the coal industry in China. The paper points out that the flotation column has come into commercial use and has good application prospects in China.

  18. Possible lunar ores

    NASA Technical Reports Server (NTRS)

    Gillett, Stephen L.

    1991-01-01

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

  19. Apparatus and method for froth flotation

    SciTech Connect

    Chin, T.H.

    1990-04-03

    This patent describes a method for the froth flotation separation of the components of a slurry having particulate matter therein which is to be separated and collected. It comprises: spraying an input slurry of particulate matter into a liquid contained in a flotation tank to create a froth on the liquid surface; removing the froth from the liquid surface by skimming means, the skimming means passing the froth over a discharge surface. The discharge surface having at least one raised ridge means disposed thereon for preventing the skimming means from contacting the portion of the discharge surface upon which the at least one raised ridge means is disposed and cooperating with the skimming means and discharge surface to separate excess liquid from the froth prior to the collection of the froth.

  20. Fundamental study of cavitation in flotation

    SciTech Connect

    Zhou, Z.A.; Xu, Z.; Finch, J.A.

    1995-12-31

    The generation of microscopic bubbles by cavitation may enhance particle-bubble attachment and improve flotation performance. It is shown in this paper that tiny bubbles or cavities can be generated by strong shear and turbulence in high speed liquid flows. These conditions create the necessary pressure fluctuations in the bulk water to cause the local pressure to drop below a critical value. The formation of bubbles is favored by high dissolved gas contents to promote gas diffusion into the cavities, and by the presence of surfactants to provide some mechanical strength due to the adsorbed film. Experimental results on bubble formation by cavitation and consequent flotation of fine silica (d{sub 50} = 1.6 {micro}m) are presented.

  1. Elk Valley coal implements smartcell flotation technology

    SciTech Connect

    Stirling, J.C.

    2008-06-15

    In anticipation of future raw coal containing higher fines content, Elk Valley Coal Corp.'s Greenhills Operations upgraded their fines circuit to include Wemco SmartCells in March 2007. Positive results were immediately achieved increasing the average flotation tailings ash by 16%. With this increase in yield the SmartCells project paid for itself in less than eight months. 2 figs., 1 tab., 1 photo.

  2. Optimizing dissolved air flotation design and saturation.

    PubMed

    Féris, L A; Gallina, C W; Rodrigues, R T; Rubio, J

    2001-01-01

    Dissolved air flotation (DAF) of iron hydroxide precipitates at working pressures lower than 3 atm, using modified flotation units to improve the collection of fragile coagula, was studied. Conventional DAF flotation was studied as a function of saturation pressure in the absence and presence of surfactants in the saturator. Without surfactants, the minimum saturation pressure required for DAF to occur was found to be 3 atm. But, by lowering the air/water surface tension in the saturator, DAF was possible at a saturation pressure of 2 atm. This behavior was found to occur in both batch and pilot DAF operation tests and almost complete recovery of the precipitates was attained. Results are explained in terms of the minimum "energy" which has to be transferred to the liquid phase to form bubbles by a cavity phenomenon. Further, studies were conducted changing equipment design and feed bubbles size distribution (mixing micro and "mid-sized" bubbles). Thus, bubbles entrance position in the collision-adhesion zone ("capture" zone) was compared to bubble entrance position in the water flow inlet below the floating bed. A "mushroom" type diffuser was used for the "capture zone" experiment and better performance was obtained. Results are explained in terms of different mass transfer phenomena in the collection zone and in the separation zone. Finally, results obtained with the use of a column flotation cell working as normal DAF and with a wide bubble size range are presented. Results indicate good performance and some gains in process kinetics with middle size bubbles. PMID:11394267

  3. Modernized system for the automatic regulation of the flotation process

    SciTech Connect

    Rozenman, E.S.; Bugaisen, I.M.; Deberdeev, I.Kh.; Livshits, A.B.; Nikitina, V.S.; Voitenko, B.I.; Bezlyudnyi, I.F.

    1984-01-01

    An improved system for automation of the flotation section of the Zaporozhye Coking Plant including control of the density and average particle size in the feedstock and regulation of addition of reagents in the overall flow is described. A block diagram of the system is included. The use of this automated system along with application of corrections to the reagent system at the flotation section improved the process and made it more economical. The ash content of the flotation wastes increased by 5-8%, the flotation-concentrate output increased by 0.5%, and its ash content was lowered by 0.2-0.4% using the automated system.

  4. The behavior of each species in coal flotation

    SciTech Connect

    Liu, W.; Lu, M.; Ren, S.; Kou, C.

    1999-07-01

    The work presented in this paper mainly focused on the study into the flotation behavior of each species at different levels of collector dosage, frother dosage, and air volumetric flow rate. Examination of the flotation response of the discrete particle size fraction reveals that the flotation behavior of each size fraction does not follow the first order model. The flotation rate constant decreases with the increase of flotation time. The recovery of minus 74 micron fraction has a good relationship with the amount of floated water. The relationship between water flotation rate, Kw, and frother dosage, collector dosage and air volumetric flow rate is also discussed. By this relationship, the amount of floated water can be predicted according to the addition rate of frother, collector and air volumetric flow rate during the flotation procedure, and further the recovery of minus 74 micron coal can also be predicted. Examination of the flotation behavior of each discrete density fraction shows that it also does not follow the first order model. A further investigation of each density fraction within the same size fraction is also conducted. It is found that the behavior of the narrower species fits the first order model well. By statistical analysis, the models, which represent the relationship between the flotation rate constant of each narrower species and the manipulated variables (frother, collector and air flow rate), have been built. On these models built above, the product quantity and quality can be predicted on-line.

  5. Advanced froth flotation techniques for fine coal cleaning

    SciTech Connect

    Yoon, R.H.; Luttrell, G.H.

    1994-12-31

    Advanced column flotation cells offer many potential advantages for the treatment of fine coal. The most important of these is the ability to achieve high separation efficiencies using only a single stage of processing. Unfortunately, industrial flotation columns often suffer from poor recovery, low throughput and high maintenance requirements as compared to mechanically-agitated conventional cells. These problems can usually be attributed to poorly-designed air sparging systems. This article examines the problems of air sparging in greater detail and offers useful guidelines for designing bubble generators for industrial flotation columns. The application of these principles in the design of a successful advanced fine coal flotation circuit is also presented.

  6. Flotation machine and process for removing impurities from coals

    DOEpatents

    Szymocha, K.; Ignasiak, B.; Pawlak, W.; Kulik, C.; Lebowitz, H.E.

    1995-12-05

    The present invention is directed to a type of flotation machine that combines three separate operations in a single unit. The flotation machine is a hydraulic separator that is capable of reducing the pyrite and other mineral matter content of a coal. When the hydraulic separator is used with a flotation system, the pyrite and certain other mineral particles that may have been entrained by hydrodynamic forces associated with conventional flotation machines and/or by the attachment forces associated with the formation of microagglomerates are washed and separated from the coal. 4 figs.

  7. Flotation machine and process for removing impurities from coals

    DOEpatents

    Szymocha, K.; Ignasiak, B.; Pawlak, W.; Kulik, C.; Lebowitz, H.E.

    1997-02-11

    The present invention is directed to a type of flotation machine that combines three separate operations in a single unit. The flotation machine is a hydraulic separator that is capable of reducing the pyrite and other mineral matter content of a coal. When the hydraulic separator is used with a flotation system, the pyrite and certain other minerals particles that may have been entrained by hydrodynamic forces associated with conventional flotation machines and/or by the attachment forces associated with the formation of microagglomerates are washed and separated from the coal. 4 figs.

  8. Flotation machine and process for removing impurities from coals

    DOEpatents

    Szymocha, Kazimierz; Ignasiak, Boleslaw; Pawlak, Wanda; Kulik, Conrad; Lebowitz, Howard E.

    1997-01-01

    The present invention is directed to a type of flotation machine that combines three separate operations in a single unit. The flotation machine is a hydraulic separator that is capable of reducing the pyrite and other mineral matter content of a coal. When the hydraulic separator is used with a flotation system, the pyrite and certain other minerals particles that may have been entrained by hydrodynamic forces associated with conventional flotation machines and/or by the attachment forces associated with the formation of microagglomerates are washed and separated from the coal.

  9. Flotation machine and process for removing impurities from coals

    DOEpatents

    Szymocha, Kazimierz; Ignasiak, Boleslaw; Pawlak, Wanda; Kulik, Conrad; Lebowitz, Howard E.

    1995-01-01

    The present invention is directed to a type of flotation machine that combines three separate operations in a single unit. The flotation machine is a hydraulic separator that is capable of reducing the pyrite and other mineral matter content of a coal. When the hydraulic separator is used with a flotation system, the pyrite and certain other minerals particles that may have been entrained by hydrodynamic forces associated with conventional flotation machines and/or by the attachment forces associated with the formation of microagglomerates are washed and separated from the coal.

  10. ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE ...

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

    ORE CONVEYANCE SYSTEM AND ADIT. LOOKING WEST. ORE FROM THE MINES ABOVE AT THE RIDGELINE AND TO THE RIGHT WAS CONVEYED TO THIS AREA AND DUMPED INTO THE SHAFT AT CENTER. THIS SHAFT OPENS INTO THE ADIT AT BOTTOM CENTER. THERE IS ANOTHER SHAFT OPENING INTO THE ADIT JUST ABOVE THE ADIT BEHIND THE STONE WALL. THE ORE WAS LOADED INTO TRAM CARS INSIDE THE ADIT AND CONVEYED ON TRACKS TO THE TRESTLE LEADING TO THE PRIMARY ORE BIN AT THE TRAM TERMINAL. TRACKS CAN BE SEEN LEADING FROM THE ADIT AND TO THE LEFT. THE ORE WAS THEN DUMPED INTO A CHUTE AT THE END OF THE TRESTLE CARRYING IT INTO THE ORE BIN AT THE TRAM TERMINAL(SEE CHUTE ON CA-291-30). - Keane Wonder Mine, Park Route 4 (Daylight Pass Cutoff), Death Valley Junction, Inyo County, CA

  11. A theoretical model of flotation deinking efficiency

    SciTech Connect

    Bloom, F.; Heindel, T.J.

    1997-06-01

    The associated probabilities of each microprocess occurring in flotation deinking are employed in the development of a kinetic or population balance-type model of the overall flotation process. The overall model contains two kinetic constants: The first, k{sub 1}, governs the overall probability of a free ink particle successfully being intercepted by and adhering to an air bubble; the second, k{sub 2}, is a measure of the probability that a particle/bubble aggregate pair will become unstable and split to yield a new free ink particle. The solution to the kinetic model is presented in terms of k{sub 1} and k{sub 2}, which are themselves functions of system parameters such as bubble and particle physical properties (e.g., diameter, density) and fluid properties (e.g., viscosity, surface tension). From this solution, a definition of theoretical flotation efficiency is presented, as well as definitions of other system performance parameters, and selected predictions are displayed.

  12. QSAR modeling of flotation collectors using principal components extracted from topological indices.

    PubMed

    Natarajan, R; Nirdosh, Inderjit; Basak, Subhash C; Mills, Denise R

    2002-01-01

    Several topological indices were calculated for substituted-cupferrons that were tested as collectors for the froth flotation of uranium. The principal component analysis (PCA) was used for data reduction. Seven principal components (PC) were found to account for 98.6% of the variance among the computed indices. The principal components thus extracted were used in stepwise regression analyses to construct regression models for the prediction of separation efficiencies (Es) of the collectors. A two-parameter model with a correlation coefficient of 0.889 and a three-parameter model with a correlation coefficient of 0.913 were formed. PCs were found to be better than partition coefficient to form regression equations, and inclusion of an electronic parameter such as Hammett sigma or quantum mechanically derived electronic charges on the chelating atoms did not improve the correlation coefficient significantly. The method was extended to model the separation efficiencies of mercaptobenzothiazoles (MBT) and aminothiophenols (ATP) used in the flotation of lead and zinc ores, respectively. Five principal components were found to explain 99% of the data variability in each series. A three-parameter equation with correlation coefficient of 0.985 and a two-parameter equation with correlation coefficient of 0.926 were obtained for MBT and ATP, respectively. The amenability of separation efficiencies of chelating collectors to QSAR modeling using PCs based on topological indices might lead to the selection of collectors for synthesis and testing from a virtual database. PMID:12444740

  13. Reef Education Evaluation: Environmental Knowledge and Reef Experience

    ERIC Educational Resources Information Center

    Stepath, Carl M.

    2005-01-01

    Background: The Reef education evaluation: environmental knowledge and reef experience report concerns PhD research about marine education, and the investigation of learning with high school students and the effect of coral reef monitoring marine experiential education interventions. The effectiveness of classroom learning and reef trips were…

  14. Great Barrier Reef

    NASA Technical Reports Server (NTRS)

    2002-01-01

    A better than average view of the Great Barrier Reef was captured by SeaWiFS on a recent overpass. There is sunglint northeast of the reef and there appears to be some sort of filamentous bloom in the Capricorn Channel.

  15. Capitol Reef Sandstone Monolith

    USGS Multimedia Gallery

    A sandstone monolith within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  16. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth. The tr...

  17. Capitol Reef Sandstone Cliff

    USGS Multimedia Gallery

    A sandstone cliff within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  18. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth.&n...

  19. Capitol Reef Panorama

    USGS Multimedia Gallery

    A panorama of some of the sandstone formations within Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in th...

  20. Capitol Reef Cliff

    USGS Multimedia Gallery

    A sandstone cliff near the entrance of Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth. This l...

  1. The Role of High Molecular Weight Polyethylene Oxide in Reducing Quartz Gangue Entrainment in Chalcopyrite Flotation by Xanthate Collectors

    NASA Astrophysics Data System (ADS)

    Gong, Jihua

    Fine particles pose two challenging problems to all mineral processors around the world today. The problems are the inefficient collection of hydrophobic particles (low recovery), and mechanical/hydraulic entrainment of hydrophilic gangue particles (low concentrate grade). Extensive research has been conducted to improve the flotation recovery of fine hydrophobic particles. However, much less effort was made to lower the mechanical/hydraulic entrainment of fine gangue mineral particles. In this study, polyethylene oxide (PEO) was used to flocculate and depress fine quartz particles. Batch flotation results indicated that the addition of low dosages of PEO improved value mineral recovery and concentrate grade in the flotation of artificial mixtures of chalcopyrite/quartz and a commercial Au-Cu sulfide ore sample. It was found that PEO adsorbed on both minerals mainly through hydrogen bonding and caused non-selective flocculation of quartz and chalcopyrite, forming large hetero-aggregates. However, the addition of potassium amyl xanthate (KAX), a specific sulfide mineral collector, adsorbed on chalcopyrite through chemical interaction, replaced PEO and caused the chalcopyrite particles to break away from the hetero-aggregates, forming separate homo-aggregates of quartz and chalcopyrite. The flotation of the chalcopyrite and the depression of the quartz were thus both improved due to the larger sizes of the homo-aggregates compared to the discrete particles. It was also observed that a completely solubilized PEO solution could not flocculate quartz, while a partially solubilized PEO solution was most effective. This was attributed to the better “bridging” functions of the undissolved PEO aggregates when it was partially solubilized. When the PEO was fully solubilized, the individual PEO molecules were probably too flexible and tended to flatten on the adsorbed solid surface and thus could not function as an effective bridging flocculant. Furthermore, it was found that PEO could function as a “collector” for quartz due to its affinity to air-water interface and quartz, and it could increase quartz entrainment when used at high dosages. Selective flocculation and depression of the quartz gangue during chalcopyrite flotation could only be achieved at low PEO dosages. The implication of these observations on how to utilize the polyethylene oxide in industrial flotation was discussed.

  2. 33 CFR 183.202 - Flotation and certification requirements.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General 183.202 Flotation and certification requirements. Each boat to which this subpart applies must be manufactured, constructed, or assembled to...

  3. 33 CFR 183.202 - Flotation and certification requirements.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2 Horsepower General 183.202 Flotation and certification requirements. Each boat to which this subpart applies must be manufactured, constructed, or assembled to...

  4. FOAM FLOTATION TREATMENT OF INDUSTRIAL WASTEWATERS: LABORATORY AND PILOT SCALE

    EPA Science Inventory

    A floc foam flotation pilot plant reduced lead and zinc in dilute solution to very low concentrations. The results suggest a number of design improvements. A simple diffusion model does not adequately describe axial dispersion at high column leadings. The floc foam flotation of z...

  5. A simple model for industrial coal flotation operation

    SciTech Connect

    Rao, T.C.; Govindarajan, B.; Barnwal, J.P.

    1995-10-01

    A simple modeling methodology has been proposed to predict the performance of industrial coal flotation circuit based on the observations made on the actual performance. The solid content in the tailings of the coal flotation circuit has been identified as a lode-star to predict the performance in terms of yield and ash content of the concentrate. The modeling parameters are directly measurable.

  6. 33 CFR 183.202 - Flotation and certification requirements.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation and certification requirements. 183.202 Section 183.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than...

  7. 33 CFR 183.112 - Flotation material and air chambers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation material and air chambers. 183.112 Section 183.112 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Inboard Boats, Inboard/Outdrive Boats, and Airboats...

  8. 33 CFR 183.225 - Flotation test for persons capacity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation test for persons capacity. 183.225 Section 183.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  9. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  10. 33 CFR 183.325 - Flotation test for persons capacity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation test for persons capacity. 183.325 Section 183.325 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or...

  11. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  12. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  13. 33 CFR 183.225 - Flotation test for persons capacity.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 33 Navigation and Navigable Waters 2 2011-07-01 2011-07-01 false Flotation test for persons capacity. 183.225 Section 183.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  14. 33 CFR 183.325 - Flotation test for persons capacity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation test for persons capacity. 183.325 Section 183.325 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or...

  15. 33 CFR 183.325 - Flotation test for persons capacity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation test for persons capacity. 183.325 Section 183.325 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or...

  16. 33 CFR 183.202 - Flotation and certification requirements.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Flotation and certification requirements. 183.202 Section 183.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than...

  17. 33 CFR 183.225 - Flotation test for persons capacity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation test for persons capacity. 183.225 Section 183.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  18. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  19. 33 CFR 183.325 - Flotation test for persons capacity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation test for persons capacity. 183.325 Section 183.325 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or...

  20. 33 CFR 183.222 - Flotation material and air chambers.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation material and air chambers. 183.222 Section 183.222 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  1. 33 CFR 183.202 - Flotation and certification requirements.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation and certification requirements. 183.202 Section 183.202 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than...

  2. 33 CFR 183.225 - Flotation test for persons capacity.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 33 Navigation and Navigable Waters 2 2010-07-01 2010-07-01 false Flotation test for persons capacity. 183.225 Section 183.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  3. 33 CFR 183.325 - Flotation test for persons capacity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Flotation test for persons capacity. 183.325 Section 183.325 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of 2 Horsepower or...

  4. 33 CFR 183.225 - Flotation test for persons capacity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Flotation test for persons capacity. 183.225 Section 183.225 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of More Than 2...

  5. Coal-flotation chemistry. Final report, 1975-1981

    SciTech Connect

    Miller, J.D.

    1982-03-01

    The Coal Preparation Division of DOE has sponsored a research program to study the chemistry of the two stage reverse flotation process in an attempt to understand important variables that determine the extent of pyritic sulfur removal. Briefly, the first step of the two stage process is simply conventional coal flotation, and the second stage, reverse flotation, involves the flotation of pyrite with a sulfhydryl collector from coal particles which are depressed with organic colloid-type depressants. The adsorption reactions involved in the second stage reverse flotation were of primary concern in this program. Research studies include: Adsorption of organic colloid depressants by coal, adsorption of xanthate by pyrite, bench scale flotation of ROM coal, coal flotation selectivity, and depressant desorption, and pyrite characterization. Experiments on the adsorption of organic colloid depressants by coal indicate that the adsorption isotherms for dextrin, amylose and cationic starch follow Langmuir behavior, and the isotherm for Aero 633 follows Freundlich behavior. These four depressants efficiently depress coal particles at rather low surface coverage (less than 10% surface saturation). Furthermore, at these low concentrations, the organic colloid depressants do not significantly influence xanthate flotation of pyrite. Microcalorimetric measurements reveal that the organic colloids are probably physically adsorbed on the coal surface by hydrophobic bonding. The adsorption of xanthate on pyrite was investigated by kinetic and thermochemical measurements. The results indicate that the rate of the adsorption reaction is controlled by an electrochemical reaction at the pyrite surface where xanthate is oxidized to dixanthogen and oxygen is reduced to water.

  6. An Advanced Control System for Fine Coal Flotation. Sixth quarter, technical progress report, July 1-September 30, 1997

    SciTech Connect

    Adel, G.T.; Luttrell, G.H.

    1997-10-27

    Over the past thirty years, process control has spread from the chemical industry into the fields of mineral and coal processing. Today, process control computers, combined with improved instrumentation, are capable of effective control in many modem flotation circuits. Unfortunately, the classical methods used in most control strategies have severe limitations when used in froth flotation. For example, the nonlinear nature of the flotation process can cause single-input, single-output lines to battle each other in attempts to achieve a given objective. Other problems experienced in classical control schemes include noisy signals from sensors and the inability to measure certain process variables. For example, factors related to ore type or water chemistry, such as liberation, froth stability, and floatability, cannot be measured by conventional means. The purpose of this project is to demonstrate an advanced control system for fine coal flotation. The demonstration is being carried out at an existing coal preparation plant by a team consisting of Virginia Polytechnic Institute and State University (VPI&SU) as the prime contractor and J.A. Herbst and Associates as a subcontractor. The objectives of this work are: (1) to identify through sampling, analysis, and simulation those variables which can be manipulated to maintain grades, recoveries, and throughput rates at levels set by management; (2) to develop and implement a model-based computer control strategy that continuously adjusts those variables to maximize revenue subject to various metallurgical, economic, and environmental constraints; and (3) to employ a video-based optical analyzer for on-line analysis of ash content in fine coal slurries.

  7. Lead removal with adsorbing colloid flotation

    SciTech Connect

    Thackston, E.L.; Wilson, D.J.; Hanson, J.S.; Miller, D.L. Jr.

    1980-02-01

    A process that removes lead from industrial waste by adsorbing colloid foam flotation has been designed and demonstrated. A system of ferric chloride and sodium lauryl sulfate, both relatively inexpensive chemicals, gave good performance with optimum dosages of sodium lauryl sulfate at 40 mg/l and trivalent iron at 150 mg/l. With optimum chemical and hydraulic conditions, the pilot plant was able to produce effluents with lead concentrations of less than 0.5 mg/l. The process may be especially attractive where space for heavy metals removal equipment is extremely limited.

  8. Reducing axial mixing in flotation columns

    SciTech Connect

    Al Taweel, A.M.; Ramadan, A.M.; Moharam, M.R.; Hassan, T.A.; El Mofty, S.M.

    1995-10-01

    The axial mixing characteristics of a pilot-scale flotation column were investigated with the objective of identifying means to mitigate the extent of axial mixing that adversely affects its grade/recovery performance. A wide range of design and operating conditions wa investigated and the experimental results, obtained using the dynamic response method, were analyzed using three axial mixing models. The dynamic response of the column can best be described using the axial dispersion model. The results obtained suggest that the value of the axial dispersion coefficient, E{sub L}, can be significantly reduced by judicial selection of hydrodynamic conditions and/or the use of column inserts that suppress the onset of hydrodynamic instabilities inherent to the operation of conventional flotation columns. Up to 40% reduction in the value of E{sub L} was thus obtained by using spargers that produce more uniform bubble sizes, while up to 30% reductions were obtained by controlling the residual frother concentration. 33 refs., 7 figs.

  9. Enhanced gravity separation: An alternative to flotation

    SciTech Connect

    Honaker, R.Q.; Paul, B.C.; Wang, D.; Ho, K.

    1995-10-01

    Recent research has shown that froth flotation is not effective at treating fine coals ({minus}28 mesh) containing a large portion of middling particles. Due to their relatively large density differences, middling particles can be separated more efficiently using gravity-based processes. The ability of gravity separators to treat fine particles has been limited by the lack of particle inertia relative to the surface drag forces. However, particle inertia can be enhanced by the application of a centrifugal field. A commercial-scale centrifugal Falcon concentrator capable of treating a mass flow rate of greater than 1 tph continuously has been used to evaluate its feasibility for treating fine coal was an alternative to froth flotation. Tests conducted on a {minus}28 mesh fine coal circuit feed have found the Falcon concentrator to be very effective at cleaning the 28 x 325 mesh size fraction. For an Illinois No. 5 coal sample, the ash content was reduced in the 100 x 325 mesh size fraction from about 18% to 8% while achieving a high combustible recovery value of nearly 97%. In addition, the total sulfur content was substantially decreased from 2.6% to 1.7%. The effects of the critical operating parameters on separation performance have been studied and their values optimized.

  10. Emulsified coal oils as flotation reagents

    SciTech Connect

    Selyanko, I.T.; Belov, K.A.; Karnozhitskii, P.V.; Ivashchenko, V.A.

    1983-01-01

    Investigations were conducted with the goal of preparing coal oils for use in coal flotation by preliminary emulsification. When added to the slurry, this oil is rapidly and uniformly distributed over the surface of the coal particles. The emulsification was conducted by mechanical dispersion in a laboratory agitator. (Under industrial conditions this process may be conducted in a centrifugal pump). A neutralized solution of acid tar (a waste from the sulfuric acid purification of crude benzol) was used as the emulsifier and emulsion stabilizer. The concentration of sulfonic acids was about 48%. Stable homogeneous emulsions were obtained at a concentration of oil up to 20% and neutralized tar of 0.2%. The size of the oil droplets in the emulsions was 2-10 microns. Experimental testing was conducted on a Mekhanobr laboratory flotation machine with a chamber 1 litter in volume. Unemulsified and emulsified coal oils from the tar refining division of the Makeevka Coke Works were investigated; screenings from the charge of the Yasinovka Coke Works (the below-0.5-mm size class) were floated. As a comparison experiments with the traditional kerosene reagent were conducted. In the experiments with anthracene oil, pitch distillates and kerosene, T-66 frothing agent was added at 140 g/ton of sludge; during the work with wash oil and naphthalene exudates T-66 was not added, assuming that the water-soluble phenols and bases contained in these oils have adequate frothing capacity. 5 references, 2 figures.

  11. Australia's Great Barrier Reef

    NASA Technical Reports Server (NTRS)

    2001-01-01

    The Great Barrier Reef extends for 2,000 kilometers along the northeastern coast of Australia. It is not a single reef, but a vast maze of reefs, passages, and coral cays (islands that are part of the reef). This nadir true-color image was acquired by the MISR instrument on August 26, 2000 (Terra orbit 3679), and shows part of the southern portion of the reef adjacent to the central Queensland coast. The width of the MISR swath is approximately 380 kilometers, with the reef clearly visible up to approximately 200 kilometers from the coast. It may be difficult to see the myriad details in the browse image, but if you retrieve the higher resolution version, a zoomed display reveals the spectacular structure of the many reefs.

    The more northerly coastal area in this image shows the vast extent of sugar cane cultivation, this being the largest sugar producing area in Australia, centered on the city of Mackay. Other industries in the area include coal, cattle, dairying, timber, grain, seafood, and fruit. The large island off the most northerly part of the coast visible in this image is Whitsunday Island, with smaller islands and reefs extending southeast, parallel to the coast. These include some of the better known resort islands such as Hayman, Lindeman, Hamilton, and Brampton Islands.

    Further south, just inland of the small semicircular bay near the right of the image, is Rockhampton, the largest city along the central Queensland coast, and the regional center for much of central Queensland. Rockhampton is just north of the Tropic of Capricorn. Its hinterland is a rich pastoral, agricultural, and mining region.

    MISR was built and is managed by NASA's Jet Propulsion Laboratory, Pasadena, CA, for NASA's Office of Earth Science, Washington, DC. The Terra satellite is managed by NASA's Goddard Space Flight Center, Greenbelt, MD. JPL is a division of the California Institute of Technology.

  12. Coral reefs in crisis.

    PubMed

    Hinrichsen, D

    1997-01-01

    This article reports on the crisis facing reefs throughout the world and the struggle to save them. Coral reefs, one of the biological wonders of the world, are among the largest and oldest living communities of plants and animals on earth, having been evolved between 200 and 450 million years ago. Located mostly in the Pacific region, most established coral reefs are now dead and only the upper layer is covered by a thin changeable skin of living coral. Reefs, over the years, have been the main source of animal protein for over 1 billion people in Asia. Countries near the coastlines, which relied on the seas, have resorted to dynamite fishing, poisoning and other illegal and dangerous techniques. Overpopulation and pollution has caused the deteriorating conditions of the 600,000 sq. km of coral reefs worldwide. Despite these conditions, the government has ignored this problem as they struggle to develop their economies at the expense of common resources. In addition, this article narrates the efforts that are exerted by governments in promoting coral reef protection and management of these coastal resources, setting the Apo Island in the Philippines as an example of good management and sustainability. PMID:12295817

  13. Coral Reef Ecosystems

    NASA Astrophysics Data System (ADS)

    Yap, Helen T.

    Coral reefs are geological structures of significant dimensions, constructed over millions of years by calcifying organisms. The present day reef-builders are hard corals belonging to the order Scleractinia, phylum Cnidaria. The greatest concentrations of coral reefs are in the tropics, with highest levels of biodiversity situated in reefs of the Indo-West Pacific region. These ecosystems have provided coastal protection and livelihood to human populations over the millennia. Human activities have caused destruction of these habitats, the intensity of which has increased alarmingly since the latter decades of the twentieth century. The severity of this impact is directly related to exponential growth rates of human populations especially in the coastal areas of the developing world. However, a more recently recognized phenomenon concerns disturbances brought about by the changing climate, manifested mainly as rising sea surface temperatures, and increasing acidification of ocean waters due to greater drawdown of higher concentrations of atmospheric carbon dioxide. Management efforts have so far not kept pace with the rates of degradation, so that the spatial extent of damaged reefs and the incidences of localized extinction of reef species are increasing year after year. The major management efforts to date consist of establishing marine protected areas and promoting the active restoration of coral habitats.

  14. SURFACTANT SPRAY: A NOVEL TECHNOLOGY TO IMPROVE FLOTATION DEINKING PERFORMANCE

    SciTech Connect

    Yulin Deng; Junyong Zhu

    2004-01-31

    Based on the fundamental understanding of ink removal and fiber loss mechanism in flotation deinking process, we developed this innovative technology using surfactant spray to improve the ink removal efficiency, reduce the water and fiber loss, reduce the chemical consumption and carry over in the flotation deinking. The innovative flotation deinking process uses a spray to deliver the frothing agent during flotation deinking to control several key process variables. The spray can control the foam stability and structure and modify the fluid dynamics to reduce the fibers entrapped in the froth layer. The froth formed at the top part of the flotation column will act as a physical filter to prevent the penetration of frothing agent into the pulp suspension to eliminate fiber contamination and unfavorable deinking surface chemistry modification due to surfactant adsorption on the fiber surface. Because of the filter effect, frothing agents will be better utilized. Under the sponsorships of the US Dept. of Energy (DOE) and the member companies of the Institute of Paper Science and Technology, we studied the chem-mechanical mechanism of surfactant spray for flotation deinking using different furnishes, chemicals, and flotation devices in the past four years. In the final year of the project, we successfully conducted mill trials at Abitibi-Consolidated, Inc., Snowflake paper recycling operation of 100% mixture of ONP/OMG. Results from laboratory, pilot-plant and mill trials indicated that surfactant spray technology can significantly reduce fiber loss in flotation deinking. It can be concluded that paper industry can profit greatly when this technology is commercialized in flotation deinking mills.

  15. Ore metals through geologic history.

    PubMed

    Meyer, C

    1985-03-22

    The ores of chromite, nickel, copper, and zinc show a wide distribution over geologic time, but those of iron, titanium, lead, uranium, gold, silver, molybdenum, tungsten, and tin are more restricted. Many of the limitations to specific time intervals are probably imposed by the evolving tectonic history of Earth interacting with the effects of the biomass on the evolution of the earth's s surface chemistry. Photosynthetic generation of free oxygen and "carbon" contributes significantlly to the diversity of redox potentials in both sedimentary and igneous-related processes of ore formation, influencing the selection of metals at the source, during transport, and at the site of ore deposition. PMID:17777763

  16. An overview of Miocene reefs

    SciTech Connect

    Jordan, C.F. Jr. ); Colgan, M.W. ); Frost, S.H. ); Glenn, E.C. ); Bosence, D. ); Esteban, M. )

    1990-05-01

    Miocene reefs lived approximately within the latitudes of 27{degree}S to 48{degree}N compared with 25{degree}S and 32{degree}N for Holocene reefs. This expansion of reef-growing environments was the result of warm Miocene climates, aided by a eustatic sea level rise and tectonic styles that provided numerous foundations for reef development. The majority of Miocene reefs are found in three main areas: (1) Southeast Asia and the western Pacific, (2) the Mediterranean-Middle East, and (3) Middle America and the Caribbean. These regions, with their distinctive suites of coral and foramineral species, formed three biological provinces; respectively, they are the Indo-Pacific, Tethyan, and Western Atlantic provinces. Miocene reefs in Southeast Asia occur in several foreland basins as patch reef complexes on paleohighs and as barrier reefs in back-arc basins. Those reefs in the Mediterranean occur as fringing reefs, middle-shelf patch reefs, or as barrier reefs on the edges of tectonic blocks associated with Alpine thrust belts. Most reefs in the Caribbean grew on isolated open-ocean highs of volcanic origin. Miocene reefs display a diversity of framework types: (1) coral-encrusting, red algal boundstones with diverse coral faunas, (2) branching coral-encrusting, red algal boundstones with a limited Poritid fauna, (3) encrusting red algal boundstones. Barrier reef systems are especially rich in encrusting red algae and robust corals; grainstones are common as interbedded sediment. Patch reef complexes, however, display muddy carbonate textures, may have less diverse coral faunas, and commonly have larger foraminifera. The global distribution of Miocene reefs is important because (1) it provides insight into a paleoclimatic view of the earth during a major greenhouse stage and (2) Miocene buildups, such as the Arun (EUR of 14 tcf) and Bima fields (EUR of about 100 MMBO), are exploration targets.

  17. Contradicting Barrier Reef relationships for Darwin's Evolution of reef types

    NASA Astrophysics Data System (ADS)

    Purdy, Edward G.; Winterer, Edward L.

    2006-02-01

    The Darwinian progressive subsidence model for the evolution of fringing reefs, barrier reefs and atolls has been generally accepted following the indisputable proof of subsidence provided by drilling results in the Pacific. Nonetheless, there are data that do not fit the expectations of the model, such as the similar lagoon depths of barrier reefs and atolls as opposed to the subsidence theorys implicit prediction that atolls should have significantly greater depths. In contrast, a great deal of evidence supports the influence of meteoric solution on barrier reef morphology. For example, the maximum lagoon depth of 56 modern barrier reefs is statistically correlated with the lagoon catchment area for modern annual rainfall. These modern rainfall patterns would seem to be a reasonable proxy for relative geographic differences in glacial lowstand rainfall, even though the absolute amounts of such rainfall are unknown. The correlation therefore suggests the importance of Pleistocene subaerial solution in contributing to barrier reef morphology. Further support for antecedent influence occurs in the form of barrier reef passes in which the depth of the reef pass is correlated with onshore drainage volumes. On a larger scale, the Cook Island of Mangaia provides evidence that solution can produce barrier reef morphology independent of reef development. In contrast, there are no examples of the subsidence-predicted lagoon transition of fringing reefs to barrier reefs to atolls. Moreover, the common occurrence of fringing reefs within barrier reefs negates subsidence as a causal factor in their presumed progressive evolutionary development. Consequently, the evidence to date suggests that a solution morphology template has been accentuated by reef construction to produce the diagnostic barrier reef morphology we see today. The importance of subsidence would seem to be in accounting for the overall thickness of the resulting carbonate caps of oceanic examples and in contributing to lagoon depth variation among the larger continental entities.

  18. Gold-bearing reefs of the Witwatersrand Basin: A model of synsedimentation hydrothermal formation

    NASA Astrophysics Data System (ADS)

    Safonov, Yu. G.; Prokof'ev, V. Yu.

    2006-12-01

    The current concepts concerning the genesis of the unique ore-bearing reefs of the Witwatersrand Basin and its gold resource potential are considered. The results of microscopic examination of ore from the Black, Ventersdorp Contact, Carbon Leader, and Vaal reefs, as well as of thermobarometric study of quartz, are presented. A model of synsedimentation hydrothermal origin of the reefs in the process of evolution of primary colloidal-disperse systems is substantiated on the basis of these results and the data published by other authors. The formation of these systems is related to the periodic gain of deep ore-bearing gas-saturated fluids. The gold mineralization was formed under conditions of partially closed systems, where various mineral-forming processes developed (metasomatism, crystallization of true solutions and gels, gel metasomatism, dispersion of crystalline phases, segregation of mineral particles, formation of early minerals, etc.). New data on REE specialization of ore-bearing fluids are discussed. The specific features of the gold, carbonic, and uranium mineralization of the intracratonic basin are emphasized.

  19. Reinforcement core facilitates O-ring installation

    NASA Technical Reports Server (NTRS)

    1965-01-01

    Reinforcement core holds O-ring in place within a structure while adjacent parts are being assembled. The core in the O-ring adds circumferential rigidity to the O-ring material. This inner core does not appreciably affect the sectional elasticity or gland-sealing characteristics of the O-ring.

  20. Swimming kinematic and flotation analysis of conscious and sedated dogs using 3 canine flotation devices.

    PubMed

    Corum, China Prentice; Wichtowski, Maja; Hetts, Suzanne; Estep, Dan; Bertone, Joseph J

    2014-12-01

    Canine flotation devices (CFDs) are very popular; however, their efficacy is still under debate. There is no oversight to standardize device testing, certification, or qualification for use. We set out to assess the biomechanical and behavioral effects of 3 CFDs on swim and flotation characteristics of dogs. High-speed video recordings were used to measure behavior, range of motion (ROM), maximum flexion angle, and cycles of motion per minute while swimming and roll, yaw, and fear or panic scoring while floating. Predictably, swimming with no CFD yielded the largest ROM and flexion angles. CFDINF was associated with the least ROM. During flotation, CFDAB and CFDRW caused significant rolling and fear, whereas CFDINF was the most stable. CFDAB was associated with cranial downpitch in 2 dogs. Interpretation of the kinematics for CFDAB and CFDRW suggests that decreased stability in the water leads to a greater forced ROM when the position of the dog was conducive to swimming. When positioning forced the dog into a downward pitch, ROM was decreased because of the increased effort for the dogs to keep their head above water. CFDINF was most stable overall owing to a decreased swim effort, with most dogs showing the lowest fear scores and absolute relaxation. CFDAB and CFDRW caused the dogs significant rolling, fear, and distress, with obvious fighting of sedation. We hope to disseminate these results to dog owners in the hopes of providing a valid assessment of these devices. PMID:25813850

  1. Microbial reduction of iron ore

    DOEpatents

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

    1989-11-14

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

  2. Microbial reduction of iron ore

    DOEpatents

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

    1989-01-01

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

  3. Flotation separation of uranium from contaminated soils

    SciTech Connect

    Misra, M.; Mehta, R.; Garcia, H.; Chai, C.D.; Smith, R.W.

    1995-08-01

    The volume of low-level contaminated soil at the Department of Energy`s Nuclear Weapon Sites are in the order of several million tons. Most of the contaminants are uranium, plutonium, other heavy metals and organic compounds. Selected physical separation processes have shown demonstrated potential in concentrating the radionuclides in a small fraction of the soil. Depending upon the size, nature of bonding and distributions of radionuclides, more than 90% of the radionuclide activity can be concentrated in a small volume of fraction of the soil. The physico-chemical separation processes such as flotation in a mechanical and microbubble tall column cell have shown promising applications in cleaning up the high volume contaminated soil.

  4. Harvesting of Algae by Froth Flotation

    PubMed Central

    Levin, Gilbert V.; Clendenning, John R.; Gibor, Ahron; Bogar, Frederick D.

    1962-01-01

    A highly efficient froth flotation procedure has been developed for harvesting algae from dilute suspensions. The method does not depend upon the addition of flotants. Harvesting is carried out in a long column containing the feed solution which is aerated from below. A stable column of foam is produced and harvested from a side arm near the top of the column. The cell concentration of the harvest is a function of pH, aeration rate, aerator porosity, feed concentration, and height of foam in the harvesting column. The economic aspects of this process seem favorable for mass harvesting of algae for food or other purposes. Images FIG. 1 FIG. 2a FIG. 2b PMID:14464557

  5. Zircon-rutile-ilmenite froth flotation process

    SciTech Connect

    Schmidt, R.; Denham, D.L. Jr.

    1992-04-21

    This patent describes a method for separating a mixture of minerals comprising at least zircon, ilmenite and rutile. It comprises adding an acid solution to the mixture to acidify to a pH of between about 2.0 and 6.0; adding starch to the mixture to depress the ilmenite and the rutile; adding a source of fluoride ions to the mixture to provide a negative surface charge on the zircon surface to activate the zircon; adding an amine cationic collector to the mixture to float the activated zircon; subjecting the mixture containing the added acid solution, the fluoride ions, the starch and the cationic collector, to froth flotation; and withdrawing a float product comprising the zircon and a sink product comprising the ilmenite and rutile.

  6. FLOTATION ROOM, LOOKING SOUTHWEST, WITH LEAD ROUGHER CELLS AT RIGHT ...

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

    FLOTATION ROOM, LOOKING SOUTHWEST, WITH LEAD ROUGHER CELLS AT RIGHT AND LEAD CLEANER CELLS AT LEFT. NOTE SUNNYSIDE GOLD CORP. "SG" LOGO ON ROUGHER CELL LAUNDER. - Shenandoah-Dives Mill, 135 County Road 2, Silverton, San Juan County, CO

  7. Colloidal titanium dioxide separation from water by foam flotation

    SciTech Connect

    Shen, Y.H.

    1998-12-01

    Colloidal titanium dioxide (TiO{sub 2}) was separated from an aqueous suspension (1,000 ppm) by foam flotation using cationic or anionic surfactants. The effects of surfactant dosage, suspension pH value, suspension ionic strength, and gas flow rate on the dispersed-air flotation of colloidal TiO{sub 2} were investigated. TiO{sub 2} separation was almost complete in optimum conditions. It was found that the coulombic interaction between charged TiO{sub 2} particle surfaces and ionic collectors plays a dominant role in this system. Both flotation rate and foamate volume are dependent upon the gas flow rate. Foam flotation may find application in the separation of submicron TiO{sub 2} particles in suspend-photocatalyst systems.

  8. Flotation of hydrophobic flocculated coal for ash rejection

    SciTech Connect

    Li, R.; Xu, Y.; Song, S.; Lu, S.

    1995-12-31

    In order to remove much more ash from the coal slurry of Tongshan coal washing plant and obtain high quality clean coal, the flotation of hydrophobic flocculated coal is studied to replace the conventional flotation.The main parameters of affecting this process such as the duration and intensity of the agitation, the amount and type of dispersant and nonpolar oil are investigated. The new process has been used to treat the coal slurry of 24.22% ash content, and the cleaned coal of 12.52% ash content with 86.58% weight recovery was obtained, compared to that of 17.78% ash content with 86.01% weight recovery by the conventional flotation. It is obvious that the flotation of hydrophobic flocculated coal is an efficient method to coal slurry beneficiation.

  9. Flotation kinetics: Methods for estimating distribution of rate constants

    SciTech Connect

    Chander, S.; Polat, M.

    1995-12-31

    Many models have been suggested in the past to obtain a satisfactory fit to flotation data. Of these, first-order kinetics models with a distribution of flotation rate constants are most common. A serious limitation of these models is that type of the distribution must be pre-supposed. Methods to overcome this limitation are discussed and a procedure is suggested for estimating the actual distribution of flotation rate constants. It is demonstrated that the classical first-order model fits the data well when applied to coal flotation in narrow size-specific gravity intervals. When applied to material which is fractionated on the basis of size alone, the use of three parameter models, which were modified from their two parameter analogs such as rectangular, sinusoidal, and triangular, gave most reliable results.

  10. Towards high throughput screening of nanoparticle flotation collectors.

    PubMed

    Abarca, Carla; Yang, Songtao; Pelton, Robert H

    2015-12-15

    To function as flotation collectors for mineral processing, polymeric nanoparticles require a delicate balance of surface properties to give mineral-specific deposition and colloidal stability in high ionic strength alkaline media, while remaining sufficiently hydrophobic to promote flotation. Combinatorial nanoparticle surface modification, in conjunction with high throughput screening, is a promising approach for nanoparticle development. However, efficient automated screening assays are required to reject ineffective particles without having to undergo time consuming flotation testing. Herein we demonstrate that determining critical coagulation concentrations of sodium carbonate in combination with measuring the advancing water contact angle of nanoparticle-saturated glass surfaces can be used to screen ineffective nanoparticles. Finally, none of our first nanoparticle library based on poly(ethylene glycol) methyl ether methacrylate (PEG-methacrylate) were effective flotation collectors because the nanoparticles were too hydrophilic. PMID:26319325

  11. DISSOLVED AIR FLOTATION TREATMENT OF GULF SHRIMP CANNERY WASTEWATER

    EPA Science Inventory

    This study reports on the operation of a plant scale dissolved air flotation system installed to define and evaluate attainable shrimp cannery wastewater treatment levels. The system was operated in all three modes of DAF pressurization. Destabilizing coagulants investigation inc...

  12. Separation of algal cells from water by column flotation

    SciTech Connect

    Liu, J.C.; Chen, Y.M.; Ju, Y.H.

    1999-08-01

    The dispersed air flotation (DiAF) process was utilized to separate algal cells (Chlorella sp.) from water. Two types of collector, cationic N-cetyl-N,N,N-trimethylammonium bromide (CTAB) and anionic sodium dodecylsulfate (SDS), were used. It was observed that 20% of cell removal was achieved in the presence of 40 mg/L of SDS, and ca. 86% of the cells were removed at 40 mg/L of CTAB. Upon the addition of 10 mg/L of chitosan, over 90% of the cells were removed when SDS (20 mg/L) was used as the collector. Air flow rate affected cell flotation slightly. Optimum pH values for cell flotation were from 4.0 to 5.0. Flotation efficiency decreased at high ionic strength. The electrostatic interaction between collector and cell surface plays a critical role in the separation processes.

  13. Coral reef hydrogeology

    SciTech Connect

    Buddemeier, R.W.; Oberdorfer, J.A.

    1985-05-21

    Knowledge of internal flow velocities and pore water residence time is important in understanding pore water geochemistry, nutrient fluxes at the benthic boundary, reef diagenesis, and fresh water resources in reef islands. Hydrogeologic studies of Pacific and Indian Ocean reef and atoll islands indicate a dual aquifer systems; the major Pleistocene aquifer has hydraulic conductivities on the order of 1000 m/d, while the overlying Holocene aquifer of unconsolidated sediments is at least an order of magnitude less permeable. The high permeability in the Pleistocene formation is the result of large voids, both constructional and from subaerial solution during low stands of the sea. Wind, wave and tide induced head differences ranging from a few centimeters to several tens of centimeters provide the driving force for internal flow. Pore water residence times and geochemistry will vary greatly, depending on whether the water is in a major flow channel or in more restricted pores. Studies of both submerged reefs and atoll islands give bulk pore water residence times on the order of months to a few years. Chemical analyses of pore water indicate that both carbonate solution and precipitation are taking place, which will alter porosity and permeability with time. The dual aquifer model also suggests that the Ghyben-Herzberg lens approach to reef island fresh water resources is inaccurate and can lead to a gross overestimation of the potable resource. 18 refs., 5 figs.

  14. Coal desulfurization by bacterial treatment and column flotation. Final report

    SciTech Connect

    Kawatra, S.K.

    1994-06-01

    A review of the literature showed that bacterial leaching, using the microorganism Thiobacillus ferrooxidans, was a very effective technique for removing pyrite from coal, as it could dissolve even the finest pyrite particles without the need for expensive reagents or extreme processing conditions. Unfortunately, bacterial leaching is also rather slow, and so the initial goal of this research was to decrease the leaching time as much as possible. However, this still left the bacteria needing approximately a week to remove half of the pyritic sulfur, and so a faster technique was sought. Since it had been reported in the literature that T. ferrooxidans could be used to depress the flotation of pyrite during froth flotation of coal, this was investigated further. By studying the recovery mechanisms of coal-pyrite in froth flotation, it was found that pyrite was being recovered by entrainment and by locking to coal particles, not by true flotation of hydrophobic pyrite. Therefore, no pyrite depressant could be of any significant benefit for keeping pyrite out of the coal froth product, and it was much more important to prevent entrainment from occurring. Countercurrent flotation columns were invented to essentially eliminate entrainment effects, by washing the froth and reducing mixing of the froth and tailings products. Existing flotation columns tend to be quite simple, and in order to give reasonable product quality they must be very tall (typically 30--45 feet). As a result, they have difficulty in handling the high froth volumes which occur in coal flotation, and are awkward to install in existing plants. The bulk of this project therefore concentrated on developing an improved coal flotation column, and testing it under actual plant conditions.

  15. Cross flow cyclonic flotation column for coal and minerals beneficiation

    SciTech Connect

    Lai, R.W.; Patton, R.A.

    2000-05-02

    An apparatus and process are disclosed for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophilic tailings.

  16. Cross flow flotation column for coal and minerals beneficiation

    SciTech Connect

    Lai, Ralph W.; Patton, Robert A.

    1997-12-01

    An apparatus and process are disclosed for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophilic tailings.

  17. A comparison study of commercially-available column flotation technologies

    SciTech Connect

    Honaker, R.Q.; Mohanty, M.K.; Paul, B.C.; Ho, K.

    1994-12-31

    A direct comparison of three commercially-available column flotation technologies, i.e., Jameson Cell, Microcel, and Packed-Column, has been conducted using a {minus}100 mesh Illinois No. 5 flotation feed coal sample. The separation performance of each flotation technology was optimized and their performance levels compared on the basis of both ash rejection, sulfur rejection, and throughput capacities. A parametric study using a statistically-designed experimental program was conducted to optimize the critical operating parameter values of each column. The ultimate performance curves for each column were generated by conducting additional tests using the optimized operating parameter values. The throughput capacity of each flotation cell was determined by conducting tests over a range of feed rates at the maximum superficial gas rate while maintaining the other parameters at their optimum values. The separation performance achieved by each of the three flotation cells was found to be comparable to the idealistic flotation performance predicted by release analysis. However, the fraction of wash water reporting to tailings (bias factor) was found to be critical in achieving the near idealistic performance. The bias factor required for the Packed-Column was found to be less than that required by the other two flotation cells. The sulfur rejection achieved by the Microcel and the Packed-Column were found to be greater than that achieved by the Jameson Cell and all three produced sulfur rejections exceeding the values obtained from release analysis. The throughput capacity, on the other hand, differed among the three flotation columns. The Jameson Cell and the Microcel were found to have comparable throughput capacities while the Packed-Column was found to have a lower capacity.

  18. Investigation of foam flotation and phase partitioning techniques

    NASA Technical Reports Server (NTRS)

    Currin, B. L.

    1985-01-01

    The present status of foam flotation as a separation process is evaluated and limitations for cells and proteins are determined. Possible applications of foam flotation to separations in microgravity are discussed. Application of the fluid mechanical aspects of foam separation techniques is made to phase partitioning in order to investigate the viscous drag forces that may effect the partitioning of cells in a two phase poly(ethylene glycol) and dextran system.

  19. Cross flow cyclonic flotation column for coal and minerals beneficiation

    DOEpatents

    Lai, Ralph W. (Upper St. Clair, PA); Patton, Robert A. (Pittsburgh, PA)

    2000-01-01

    An apparatus and process for the separation of coal from pyritic impurities using a modified froth flotation system. The froth flotation column incorporates a helical track about the inner wall of the column in a region intermediate between the top and base of the column. A standard impeller located about the central axis of the column is used to generate a centrifugal force thereby increasing the separation efficiency of coal from the pyritic particles and hydrophillic tailings.

  20. Coal surface control for advanced fine coal flotation

    SciTech Connect

    Fuerstenau, D.W.; Sastry, K.V.; Hanson, J.S.; Harris, G.; Sotillo, F.; Diao, J.; De, A. ); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. ); Hu, Weibai; Zou, Y.; Chen, W. ); Choudhry, V.; Sehgal, R.; Ghosh, A. )

    1991-03-22

    The main goal of the project is to characterize the surface and control the behavior of coal during advanced flotation processing in order to achieve an overall objective of near-total pyritic sulfur removal with a high Btu recovery. Also, investigation of the effects of weathering on the surface characteristics of coal is another important aspect of this project. The effect of butanol, dodecane, lime, calcium cyanide, hydrogen peroxide, and ph on flotation performance is discussed. 2 refs., 26 figs., 18 tabs.

  1. Boiling treatment of ABS and PS plastics for flotation separation.

    PubMed

    Wang, Chong-qing; Wang, Hui; Wu, Bao-xin; Liu, Qun

    2014-07-01

    A new physical method, namely boiling treatment, was developed to aid flotation separation of acrylonitrile-butadiene-styrene (ABS) and polystyrene (PS) plastics. Boiling treatment was shown to be effective in producing a hydrophilic surface on ABS plastic. Fourier Transform Infrared analysis was conducted to investigate the mechanism of boiling treatment of ABS. Surface rearrangement of polymer may be responsible for surface change of boiling treated ABS, and the selective influence of boiling treatment on the floatability of boiling treated plastics may be attributed to the difference in the molecular mobility of polymer chains. The effects of flotation time, frother concentration and particle size on flotation behavior of simple plastic were investigated. Based on flotation behavior of simple plastic, flotation separation of boiling treatment ABS and PS with different particle sizes was achieved efficiently. The purity of ABS and PS was up to 99.78% and 95.80%, respectively; the recovery of ABS and PS was up to 95.81% and 99.82%, respectively. Boiling treatment promotes the industrial application of plastics flotation and facilitates plastic recycling. PMID:24602834

  2. Application of electrochemical investigation methods in high sulfur coal flotation

    SciTech Connect

    Zhu Hong; Ou Zeshen; Shi Xiuping; Shen Yanchun

    1997-12-31

    More and more attention has been paid to sulfur dioxide pollution caused by coal burning. It is important that sulfur in coal should be reduced before combustion. Flotation is an important method for the removal of pyrite from high sulfur coal. Many chemicals have been tested as a pyrite depressant. In recent years many tests have been done in the laboratory on the flotation behavior of pyrite, and the results have confirmed that the hydrophobicity of the pyrite surface is dependent on the redox potential of the pulp. The mechanism and the reaction products on the pyrite surface are discussed under various conditions. And pyrite depression in coal flotation by electrochemical control are further studied on the basis of what has been achieved. There are two methods in electrochemical control: chemical reagent and control potential by electrochemical instrument (``control potential`` for short). This paper studies pyrite depression in coal flotation by electrochemical control. The influence of sulfur removal in coal flotation has been probed by chemical reagent and control potential. Experiment shows that at low pulp potential the pyrite flotation is generally suppressed. This is new, efficient and simple method of pyrite depression without environmental pollution. The following main conclusions can be drawn from this study: (1) The control of pulp potential can regulate and lead to electrochemical reaction of the hydrophobicity or hydrophilicity on the pyrite surface; and (2) The characteristics of electrochemical methods are normal atmospheric temperature, simple technological process and strong selection.

  3. Selective flotation of fossil resins from Northeast China coal

    SciTech Connect

    Hua, X.; Bo, H.; Qing, X.; Lijian, L.; Rong-Zeng, Z.

    1999-07-01

    For a feed which came from Northeast China containing 11.4 per cent fossil resin, by conventional single stage flotation, the fossil resin concentrate gained had a low grade. Adjusting the pH of the feed slurry with HCl or CaO before flotation or treating the feed with H{sub 2}O{sub 2} solution before flotation did not improve the selectivity of flotation. In order to improve the selectivity of flotation for fossil resin, the authors treated the feed slurry of flotation with several surfactants. Although most of them did not work very well, one surfactant was able to increase the grade of concentrate to over 80% as the recovery rate was higher than 82%. The result of mechanism research into the performance of the best surfactant indicated that the selective adsorption of the hydrophobic side of the surfactant onto the surface of coal particle made it more hydrophilic, so that the difference between the hydrophobicity of the coal particle's surface and that of the fossil resin's surface was enlarged.

  4. Interfacial interactions between plastic particles in plastics flotation.

    PubMed

    Wang, Chong-qing; Wang, Hui; Gu, Guo-hua; Fu, Jian-gang; Lin, Qing-quan; Liu, You-nian

    2015-12-01

    Plastics flotation used for recycling of plastic wastes receives increasing attention for its industrial application. In order to study the mechanism of plastics flotation, the interfacial interactions between plastic particles in flotation system were investigated through calculation of Lifshitz-van der Waals (LW) function, Lewis acid-base (AB) Gibbs function, and the extended Derjaguin-Landau-Verwey-Overbeek potential energy profiles. The results showed that van der Waals force between plastic particles is attraction force in flotation system. The large hydrophobic attraction, caused by the AB Gibbs function, is the dominant interparticle force. Wetting agents present significant effects on the interfacial interactions between plastic particles. It is found that adsorption of wetting agents promotes dispersion of plastic particles and decreases the floatability. Pneumatic flotation may improve the recovery and purity of separated plastics through selective adsorption of wetting agents on plastic surface. The relationships between hydrophobic attraction and surface properties were also examined. It is revealed that there exists a three-order polynomial relationship between the AB Gibbs function and Lewis base component. Our finding provides some insights into mechanism of plastics flotation. PMID:26337962

  5. Modelling Of Flotation Processes By Classical Mathematical Methods - A Review

    NASA Astrophysics Data System (ADS)

    Jovanović, Ivana; Miljanović, Igor

    2015-12-01

    Flotation process modelling is not a simple task, mostly because of the process complexity, i.e. the presence of a large number of variables that (to a lesser or a greater extent) affect the final outcome of the mineral particles separation based on the differences in their surface properties. The attempts toward the development of the quantitative predictive model that would fully describe the operation of an industrial flotation plant started in the middle of past century and it lasts to this day. This paper gives a review of published research activities directed toward the development of flotation models based on the classical mathematical rules. The description and systematization of classical flotation models were performed according to the available references, with emphasize exclusively given to the flotation process modelling, regardless of the model application in a certain control system. In accordance with the contemporary considerations, models were classified as the empirical, probabilistic, kinetic and population balance types. Each model type is presented through the aspects of flotation modelling at the macro and micro process levels.

  6. Reclaiming the island reefs.

    PubMed

    Bolido, L; White, A

    1997-01-01

    This article reports on the crisis facing the Philippine¿s coral reefs and their effort to reclaim its previous grandeur on a local and regional level. Faced with growing destruction of the coral reefs, the Philippine government agencies and nongovernmental organizations have taken steps to solve the problem. But even more significant is the growing trend among local communities in taking the initiative to restore and conserve their natural resources. This local effort all started from a much-admired initiative of the Silliman University, which is based in Negros Oriental's capital city of Dumaguete, in getting people to recognize and act on the need to protect and preserve their coral reefs and marine resources. The major achievement made by the University was the formation of the community-based Marine Conservation and Development Program in 1985, which sparked a series of initiatives among local communities in protecting the Philippine coastlines. PMID:12295813

  7. Optimization of Cu-Zn Massive Sulphide Flotation by Selective Reagents

    NASA Astrophysics Data System (ADS)

    Soltani, F.; Koleini, S. M. J.; Abdollahy, M.

    2014-10-01

    Selective floatation of base metal sulphide minerals can be achieved by using selective reagents. Sequential floatation of chalcopyrite-sphalerite from Taknar (Iran) massive sulphide ore with 3.5 % Zn and 1.26 % Cu was studied. D-optimal design of response surface methodology was used. Four mixed collector types (Aer238 + SIPX, Aero3477 + SIPX, TC1000 + SIPX and X231 + SIPX), two depressant systems (CuCN-ZnSO4 and dextrin-ZnSO4), pH and ZnSO4 dosage were considered as operational factors in the first stage of flotation. Different conditions of pH, CuSO4 dosage and SIPX dosage were studied for sphalerite flotation from first stage tailings. Aero238 + SIPX induced better selectivity for chalcopyrite against pyrite and sphalerite. Dextrin-ZnSO4 was as effective as CuCN-ZnSO4 in sphalerite-pyrite depression. Under optimum conditions, Cu recovery, Zn recovery and pyrite content in Cu concentrate were 88.99, 33.49 and 1.34 % by using Aero238 + SIPX as mixed collector, CuCN-ZnSO4 as depressant system, at ZnSO4 dosage of 200 g/t and pH 10.54. When CuCN was used at the first stage, CuSO4 consumption increased and Zn recovery decreased during the second stage. Maximum Zn recovery was 72.19 % by using 343.66 g/t of CuSO4, 22.22 g/t of SIPX and pH 9.99 at the second stage.

  8. Interfacial electrochemistry of pyrite oxidation and flotation. 1: Effect of borate on pyrite surface oxidation

    SciTech Connect

    Wang, X.H.

    1996-03-25

    The interfacial chemistry of pyrite is of great industrial importance in complex sulfide ore flotation, coal desulfurization, acid mine drainage mitigation, and conversion of solar energy to electrical or chemical energy. Sodium tetraborate (Na{sub 2}B{sub 4}O{sub 7}) has been widely used as an electrolyte and pH buffer in studying the interfacial electrochemistry of sulfide minerals in relation to sulfide mineral flotation. In all the previous studies published so far, borate was regarded as an inert electrolyte/pH buffer, and its reactions with the sulfide minerals were completely overlooked. In this first part of this series papers, the complicating effects of borate on the interfacial electrochemistry of pyrite have been studied. In the borate solutions, the surface oxidation of pyrite is strongly enhanced. The first and rate-determining step of the reaction between borate and pyrite has been shown to be the following irreversible reaction: FeS{sub 2} + B(OH){sub 4}{sup {minus}} {yields} FeS{sub 2} {hor_ellipsis} [B(OH){sub 4}]{sub ads} + e. This reaction appears in the voltammogram as an anodic oxidation peak at potentials of more than 0.4 V lower than the commencement of pyrite oxidation in sodium perchlorate or nitrate electrolyte solutions. As the borate concentration increases, the peak current increases linearly, while the peak potential shifts positively at 240 mV per decade. On a rotating-disc electrode, the peak becomes a plateau. The limiting current density is a linear function of the square root of the rotation speed at relatively low rotation speeds. The Tafel slope is close to 240 mV per decade and is independent of the rotation speed and borate concentration. The results indicate that charge transfer coefficient is 0.25.

  9. Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types

    NASA Astrophysics Data System (ADS)

    Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C.; Braithwaite, Colin; Kennedy, David M.; Spencer, Tom; Webster, Jody M.; Woodroffe, Colin D.

    2014-05-01

    In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy.

  10. Postglacial fringing-reef to barrier-reef conversion on Tahiti links Darwin's reef types.

    PubMed

    Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C; Braithwaite, Colin; Kennedy, David M; Spencer, Tom; Webster, Jody M; Woodroffe, Colin D

    2014-01-01

    In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy. PMID:24845540

  11. Postglacial Fringing-Reef to Barrier-Reef conversion on Tahiti links Darwin's reef types

    PubMed Central

    Blanchon, Paul; Granados-Corea, Marian; Abbey, Elizabeth; Braga, Juan C.; Braithwaite, Colin; Kennedy, David M.; Spencer, Tom; Webster, Jody M.; Woodroffe, Colin D.

    2014-01-01

    In 1842 Charles Darwin claimed that vertical growth on a subsiding foundation caused fringing reefs to transform into barrier reefs then atolls. Yet historically no transition between reef types has been discovered and they are widely considered to develop independently from antecedent foundations during glacio-eustatic sea-level rise. Here we reconstruct reef development from cores recovered by IODP Expedition 310 to Tahiti, and show that a fringing reef retreated upslope during postglacial sea-level rise and transformed into a barrier reef when it encountered a Pleistocene reef-flat platform. The reef became stranded on the platform edge, creating a lagoon that isolated it from coastal sediment and facilitated a switch to a faster-growing coral assemblage dominated by acroporids. The switch increased the reef's accretion rate, allowing it to keep pace with rising sea level, and transform into a barrier reef. This retreat mechanism not only links Darwin's reef types, but explains the re-occupation of reefs during Pleistocene glacio-eustacy. PMID:24845540

  12. Coral reef resilience through biodiversity

    USGS Publications Warehouse

    Rogers, Caroline S.

    2013-01-01

    Irrefutable evidence of coral reef degradation worldwide and increasing pressure from rising seawater temperatures and ocean acidification associated with climate change have led to a focus on reef resilience and a call to “manage” coral reefs for resilience. Ideally, global action to reduce emission of carbon dioxide and other greenhouse gases will be accompanied by local action. Effective management requires reduction of local stressors, identification of the characteristics of resilient reefs, and design of marine protected area networks that include potentially resilient reefs. Future research is needed on how stressors interact, on how climate change will affect corals, fish, and other reef organisms as well as overall biodiversity, and on basic ecological processes such as connectivity. Not all reef species and reefs will respond similarly to local and global stressors. Because reef-building corals and other organisms have some potential to adapt to environmental changes, coral reefs will likely persist in spite of the unprecedented combination of stressors currently affecting them. The biodiversity of coral reefs is the basis for their remarkable beauty and for the benefits they provide to society. The extraordinary complexity of these ecosystems makes it both more difficult to predict their future and more likely they will have a future.

  13. The evolution of reef communities

    SciTech Connect

    Fagerstrom, J.A.

    1987-01-01

    This book discusses the composition, structure, occurrence, and changes in reefs during the past 2 billion years. It emphasizes the functional roles of major groups (guilds) of reef-building, reef-destroying, and reed-dwelling organisms in the most complex of all marine communities. A structural model, based on modern reef guilds, is developed. Then the functional roles of each major reef-building higher biologic taxon (algae, sponges, coral, etc.) is determined, and, on this basis, each such taxon is assigned to a reef community guild. Next, the authors traces the geologic history and guild assignment of each major taxon through geologic time. The final chapter establishes a succession of ten major reef community types, and considers their extinction and recovery in the light of modern theories of cosmic and earthly events.

  14. Removal of Wax and Stickies from OCC by Flotation

    SciTech Connect

    M. R. Doshi; J. Dyer

    2000-01-31

    Laboratory research indicates that wax is amenable to removal by froth flotation provided it is free or detached from the fiber. The only effective means, at this time, of maximizing detachment of wax is through the use of low consistency pulping at temperatures above the melting point of wax. Wax removal from WCC through washing, flotation, or a combination of both was approximately 90% in these laboratory studies, indicating that not all of the wax is detached from fibers. These results were summarized in Annual Report 1, December 1, 1997 to November 30, 1998. Pilot trials were conducted in which the authors simulated a conventional OCC repulping process with and without flotation. Additional aggressive washing and water clarification were also examined during the study. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots and extractable material from the furnish. Based on this study, the authors predict that a compact flotation system with 2 lb surfactant/ton of fiber would improve the OCC pulp quality with regard to wax spots by 60% and would not negatively affect strength properties. Flotation losses would be in the 2-5% range. Two mill trials were conducted during the last quarter of the project. One trial was carried out at Green Bay Packaging, Green Bay, WI, and a second trial was conducted at Menasha Corporation, Otsego, MI. A 250-liter Voith Sulzer Ecocell was used to evaluate the removal of wax and stickies from the OCC processing systems at these two mills. The inclusion of flotation in the OCC stock preparation system significantly improved the removal of wax spots from the furnish. The data indicate that flotation was more effective in removing wax and stickies than reverse cleaners. The mill trials have demonstrated that flotation can be substituted for or replace existing reverse cleaning systems and, in some cases, can replace dispersion systems. In this manner, the use of flotation can provide significant energy savings when compared to reverse cleaning or dispersion.

  15. Reef talus: A popular misconception

    NASA Astrophysics Data System (ADS)

    Braithwaite, Colin J. R.

    2014-01-01

    Reef fronts have traditionally been regarded as comprising debris derived by contemporaneous erosion of 'the reef'. However, evidence from wave transport indicates that on present-day reefs the bulk of the debris generated in this way accumulates in the back-reef area, with only finer-grained sediment carried off-reef by retreating flows or by overwash. Nevertheless, in contrast to this observation, 'fore-reef' debris slopes are commonly considered "characteristic" of Phanerozoic reefs. This apparent error reflects the conflation of processes defining contemporary growth and accretion of the reef, and the corresponding long-term accretion of the carbonate platform on which it rests. Present-day reefs are commonly (although not exclusively) additions to long-lived carbonate platforms. Growth of the latter is intermittent and has been moderated by changes in sea-level that, for recent reefs, have been on time scales of less than 100 ka. During low sea-level stands, growth ceases or is translated downslope and earlier deposits are subject to lithification and subaerial erosion. Similar changes are applied on a larger scale to the aggrading growth of carbonate platforms, but the bulk accretion of these includes quite different processes and reflects far longer timescales. During low sea-level stands, the margins of platforms commonly become unstable, with instability reflected in slope failure and in the shedding of blocks, ranging from metres to kilometres in diameter, associated with the generation of debris flows and turbidites. It is argued that these are the materials that are commonly described as 'reef talus' in ancient structures, although their formation is largely independent of any contemporary reef growth. Difficulties arise where 'the reef' and 'the platform' are treated as a single functional entity. It is important to recognize the conceptual distinction between them, 'reef talus' is a misleading description of the debris predominantly generated by platform erosion and slope failure.

  16. Coral Reef Biological Criteria

    EPA Science Inventory

    Coral reefs worldwide are experiencing decline from a variety of stressors. Some important stressors are land-based sources of pollution and human activities in the coastal zone. However, few tools are available to offset the impact of these stressors. The Clean Water Act (CWA...

  17. CORAL REEF BIOCRITERIA

    EPA Science Inventory

    Coral reefs worldwide are experiencing the greatest decline of their known existence and few tools are available to offset the growing impacts of human coastal and watershed activities. Biocriteria are a potentially effective means to evaluate and restore impaired waters, but are...

  18. Capitol Reef's Castle

    USGS Multimedia Gallery

    A view of the Castle, a prominent sandstone formation in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinl...

  19. Castle in Capitol Reef

    USGS Multimedia Gallery

    A view of the Castle, a prominent sandstone formation in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinl...

  20. Capitol Reef Petroglyphs

    USGS Multimedia Gallery

    From about 300-1300 CE, ancestors of the Hopi Tribe, Pueblo of Zuni, and Paiute Tribe lived in Capitol Reef. They are known by various names-archeologists call them the Fremont Culture; the Hopi Tribe calls them the Hisatsinom, or the

  1. Petroglyphs in Captiol Reef

    USGS Multimedia Gallery

    From about 300-1300 CE, ancestors of the Hopi Tribe, Pueblo of Zuni, and Paiute Tribe lived in Capitol Reef. They are known by various names-archeologists call them the Fremont Culture; the Hopi Tribe calls them the Hisatsinom, or the

  2. Selective flotation for the removal of radionuclides from contaminated soil

    SciTech Connect

    Miller, J.D.; Yu, Q.; Lu, Y.Q.

    1995-08-01

    Low-level radioactive contaminated soils (10--500 pci/gm) created by defense-related activities at certain Superfund sites, such as Nevada Test Site (NTS), is a current environmental concern. Many of these contaminated sites may require appropriate cleanup and restoration, which could cost billions of dollars and put tremendous pressure on limited financial resources. Therefore, the development of a selective flotation process to separate such radionuclides from contaminated soils should be considered. In this study, both a pure depleted UO{sub 2} sample and three synthetic UO{sub 2}/soil mixtures were used to evaluate surface chemistry features and to examine the possibility for the flotation of fine UO{sub 2} particles from selected soils. It was intended that this model system would be a reasonable representation of contaminated soils such as those found the Nevada Test Site which are reported to be contaminated by PuO{sub 2} fallout. The effect of reagent schedule, particle size distribution, and surface charge are discussed with respect to the flotation separation of the UO{sub 2}/soil mixtures. It was found that both commercial fatty acids and reagent grade sodium oleate are effective collectors for UO{sub 2} flotation provided the pH is adjusted to the range of pH 8--9. The bench-scale flotation results successfully demonstrated that froth flotation technology can be used to remove UO{sub 2} from such model contaminated soils with appropriate flotation chemistry conditions which depend on the soil characteristics and other pretreatment procedures.

  3. Role of the collecting agent sorption forms in the elementary act of flotation

    SciTech Connect

    Abramov, A.A.

    2005-02-01

    A new hypothesis of flotation is substantiated based on the well-known hypotheses, theoretical analysis of the elementary act, and experimental results. The hypothesis presented allows the processes of flotation activation, depression, and intensification to be explained and optimized.

  4. Miocene reefs in western Mediterranean

    SciTech Connect

    Esteban, M.

    1988-01-01

    Coral reefs were particularly abundant and well developed during the late Tortonian and Messinian in southeastern Spain, the Balearic Islands, Italy, Sicily, Algeria, and Morocco. These reefs occurred just before and during the deposition of the thick Messinian evaporite units in the basinal areas and disappeared completely from Mediteranean during the early Pliocene. Most of the coral reefs are fringing terrigenous coastal fan complexes with very small lagoons and show progradation of less than 2 km. Some of the reefs occur on, or are intercalated with, Neogene volcanics or Messinian evaporites. Barrier-reef complexes are less common, have extensive lagoons behind them, and show complex progradational geometries more than 10 km wide. Excellent outcrops allow detailed reconstruction of paleogeography and sea level changes. Progradation predominated during phases of relative sea level drops and stillsands, while significant retrogradation occurred during sea level rises. The coral reef wall framework is commonly less than 20 m thick and is dominated by Porites and, locally, Tarbellastrae. Older Miocene reefs are less well developed, but show greater diversity of corals and reef organisms. Younger Miocene reef complexes occurring in open ocean settings are formed by only one branching coral genus (Porites or, locally, Tarbellastraea) with branching colonies up to 7 m high. Halimeda sands are particularly abundant in the upper reef slopes with occasional intercalations of red algae pavements that most likely coincide with episodes of terrigenous influx.

  5. The Barrier Reef sediment apron: Tobacco Reef, Belize

    NASA Astrophysics Data System (ADS)

    MacIntyre, Ian G.; Graus, Richard R.; Reinthal, Peter N.; Littler, Mark M.; Littler, Diane S.

    1987-07-01

    Sedimentological and biological surveys of the back-reef sediment apron of Tobacco Reef, a continuous segment of the Belizean Barrier Reef, reveal five distinct biogeological zones: (1) coralline-coral- Dictyota pavement, (2) Turbinaria-Sargassum rubble, (3) Laurencia-Acanthophora sand and gravel, (4) bare sand and 95 Thalassia sand. These zones parallel the entire 9-km reef. The distribution of these zones is related to the spatial patterns of fish herbivory, the size of bottom sediments, and the stability of the substrate. Sedimentological and hydrodynamic studies indicate that most of the sediments in this area are transported from the reef crest and fore reef during periods of storm or hurricane activity and that their size distribution is largely the result of differential transport by high bottom-water velocities during those periods.

  6. Basics of screening chemicals for coal flotation

    SciTech Connect

    Klimpel, R.R.

    1995-08-01

    The process of froth flotation as a means of upgrading the quality of coal by removing water and/or ash and/or pyrite has been receiving increasing attention since the 1960`s by the world-wide coal industry. Historically, coal preparation practice has involved the use of primarily gravity based separation techniques, screening, and/or water washing in removing the larger fragments of inert material from coarse raw feed coal. The preparation, handling of cleaning of raw coal finer than 500 micrometers was deliberately avoided. Most often the fine coal that was produced would be judiciously incorporated into the bulk of the larger sized cleaned coal product or simply discarded. Since the 1960`s and accelerating in the 1970`s, the desirability of performing some type of coal cleaning or upgrading on the finer raw coal feed materials has been increasing. There are several apparent industrial incentives for implementing fine coal (<500 {approximately}m) processing alternatives including the gradually increasing value of the normally lost fine coal product; the additional amounts of fine coal being produced due to changes in mining techniques; the need to appropriately dewater and upgrade fine coal streams in order to meet increasingly stringent environmental regulations on water quality, storage of fines, etc.; the increasing need to lower undesired sulfur and ash contents in some coal end-use applications; and the increasing development of specialty coal use processes that require inherently finer and cleaner coal articles such as in gasification, liquefaction, fuel injection, etc.

  7. SRB O-ring free response analysis

    NASA Technical Reports Server (NTRS)

    Moore, Carleton J.

    1986-01-01

    The free response of viton O-rings were investigated. Two different response mechanisms of viton O-rings are identified and a theoretical representation of the two mechanisms is compared with experimental results for various temperatures.

  8. Nanoparticle flotation collectors II: the role of nanoparticle hydrophobicity.

    PubMed

    Yang, Songtao; Pelton, Robert

    2011-09-20

    The ability of polystyrene nanoparticles to facilitate the froth flotation of glass beads was correlated to the hydrophobicity of the nanoparticles. Contact angle measurements were used to probe the hydrophobicity of hydrophilic glass surfaces decorated with hydrophobic nanoparticles. Both sessile water drop advancing angles, θ(a), and attached air bubble receding angle measurements, θ(r), were performed. For glass surfaces saturated with adsorbed nanoparticles, flotation recovery, a measure of flotation efficiency, increased with increasing values of each type of contact angle. As expected, the advancing water contact angle on nanoparticle-decorated, dry glass surfaces increased with surface coverage, the area fraction of glass covered with nanoparticles. However, the nanoparticles were far more effective at raising the contact angle than the Cassie-Baxter prediction, suggesting that with higher nanoparticle coverages the water did not completely wet the glass surfaces between the nanoparticles. A series of polystyrene nanoparticles was prepared to cover a range of surface energies. Water contact angle measurements, θ(np), on smooth polymer films formed from organic solutions of dissolved nanoparticles were used to rank the nanoparticles in terms of hydrophobicity. Glass spheres were saturated with adsorbed nanoparticles and were isolated by flotation. The minimum nanoparticle water contact angle to give high flotation recovery was in the range of 51° < θ(np(min)) ≤ 85°. PMID:21830818

  9. High intensity conditioning to improve flotation of gold fine particles

    SciTech Connect

    Valderrama, L.; Perez, C.; Rubio, J.

    1995-12-31

    This work describes the effect of the degree of energy transferred to the pulp, during the conditioning stage, on gold flotation fines recovery, grade and kinetics, with three types of frother (Dowfroth 250, pine oil and MIBC) and amyl xanthate as collector. Best results show an increase in 24% recovery and 50% in concentrate grade, depending on the intensity of conditioning and type of frother (better with Dowfroth 250). For low or intermediate energies (0.5--1.5 kWh/m3 pulp), the fine particles adhere to larger ones, increasing the recovery due to a mixture of carrier (pyrite, in this case) and autogeneous carrier flotation and at higher shear (2--3 kWh/m3 pulp), gold fine particles aggregate themselves. These phenomena are demonstrated by measurements of flotation rate, true flotation (flotation by actual particle-bubble adhesion), and by the amount of entrained particles. Alternatives for this type of pulp conditioning and mechanisms involved are discussed.

  10. [A simple flotation and McMaster method (author's transl)].

    PubMed

    Henriksen, S A; Aagaard, K

    1976-01-01

    A simple and hygienic flotation and McMaster method is described (cf. Fig. 1): The faeces sample (3-5 gm) is mixed with flotation fluid (40-60 ml) in a disposable plastic cup (cup I) and a circular piece of gauze, with a diameter equivalent to twice the height of the cup plus the diameter of its base, is placed over the cup. By a similar cup (cup II), with the bottom cut off and slits made in the side, the gauze is pressed down in cup I. By this procedure the faeces suspension will be filtered through the gauze and appear in cup II. After 10 minutes some drops after transferred from the surface of the filtrate to a slide by means of a test tube, which is dipped to the bottom of the filtrate and quickly moved over to the slide. The optimal procedure was worked out with faeces containing faeces containing eggs of Ostertagia ostertagi. Saturated sodium chloride with 50 g glucose per 100 ml was found to be a suitable flotation fluid for demonstrating eggs of commonly occurring parasites, e.g., trichostronglyids and ascarids. The described flotation technique is more efficacious than the one hitherto employed. The technique is usable also in connection with a McMaster method: 4 gm. faeces are suspended in 56 ml flotation fluid. Immediately following filtration, filtrate is transferred to a McMaster counting chamber by means of a Pasteur pipette. PMID:958869

  11. Quantitative evaluation of environmental risks of flotation tailings from hydrothermal sulfidation-flotation process.

    PubMed

    Xie, Xian-De; Min, Xiao-Bo; Chai, Li-Yuan; Tang, Chong-Jian; Liang, Yan-Jie; Li, Mi; Ke, Yong; Chen, Jie; Wang, Yan

    2013-09-01

    Floatation tailings (FT) are the main by-products of the hydrothermal sulfidation-flotation process. FT (FT1 and FT2) were obtained by treating two different neutralization sludges (NS) (NS1 and NS2). This paper quantitatively evaluated the environmental risks of heavy metals (Zn, Cd, Cu, Pb, and As) in FT versus NS. The total concentration and leaching rates (R 2) of heavy metals in FT were much lower than those in NS, demonstrating that the hydrothermal sulfidation-flotation process was able to effectively suppress the mobility and leachability of heavy metals. The BCR-three sequence leaching procedure of FT confirmed that all metals were transformed into more stable forms (residue and oxidizable forms) than were found that in NS. The potential ecological risk index indicated that the overall risks caused by heavy metals decreased significantly from 6627.59 and 7229.67 (very serious risk) in NS1 and NS2, respectively, to 80.26 and 76.27 (low risk) in FT1 and FT2, respectively. According to the risk assessment code, none of the heavy metals in FT posed significant risk to the natural environment except Zn (with low risk). In general, the risk of heavy metals in FT had been well controlled. PMID:23529403

  12. Two types of ore-bearing mafic complexes of the Early Proterozoic East-Scandinavian LIP and their ore potential

    NASA Astrophysics Data System (ADS)

    Mitrofanov, Felix; Zhirov, Dmitry; Bayanova, Tamara; Korchagin, Alexey; Chaschin, Victor

    2015-04-01

    Two types of the ore-bearing mafic complexes are allotted in the East-Scandinavian large igneous province (LIP). They differ in geodynamic setting, structure, isotope geochemistry, petrology and mineralogy. The PGE-bearing mafic-ultramafic layered intrusions are associated with the first complex. They have been formed at an initial (pre-rift) stage of LIP. Features of origin of this complex are: 1) large-scale, protracted, and multiple episodes of deep mantle plume or asthenosphere upwelling; 2) the vast non-subduction-type basaltic magma in an intraplate continental setting; 3) low-sulfide Pt-Pd (with Ni, Cu, Au, Co and Rh) mineralization in different geological setting (reef- and contact type etc.); 4) anomalously high concentrations of PGEs in the bulk sulfides, inferred platinum distribution coefficient between silicate and sulfide melts of >100000. Deep mantle magma source is enriched in ore components (fertile source) and lithophile elements. It is reflected in the isotope indicators such as ɛNd(T) from -1 to -3, ISr(87Sr/86Sr) from 0.702 to 0.704, 3Не/4Не = (10 ^-5 ÷ 10 ^-6). Magma and ore sources differ from those of Mid-Ocean Ridge basalts (MORB), subduction-related magma but are similar to EM-I. Ore-bearing mafic complexes formed during a long period of time and by different episodes (2490±10 Ma; 2470±10 Ma; 2450±10 Ma; 2400±10 Ma), and by mixing between the boninitic an anorthositic magmas. It is known about 10 deposits and occurrences in Kola region with total reserves and resources about 2000 tons in palladium equivalent (with an average content ≥2-3 ppm). Intrusions with the rich sulfide Ni-Cu ore (with Co and poor PGE) are associated with the second mafic complex. Ore-controlling mafic-ultramafic intrusions are formed at a final stage of the intracontinental rifting of the Transitional period (2200-1980 Ma). Initial magma is depleted and similar to the MORB in terms of rare earths distribution. Enriched ferropicritic Fe-Ti derivatives of magma generate single volcano-plutonic rock series. For intrusive ore bodies rock differentiation with the formation of syngenetic wehrlite-clinopyroxenite-gabbro- orthoclase gabbro sequence is typical. Upper mantle source of the depleted magma is characterized by the following isotope indicators: ɛNd(T) +0.5 to +4, ISr= 87Sr/86Sr 0.703-0.704. Ore-bearing intrusive bodies are injected in the upper part of the Early Palaeoproterozoic volcano-sedimentary cross-section. Ores are located in the basement of intrusions and in the redeposited veined bodies, including offset setting. Numerous Ni-Cu deposits with total reserves and resources of several million tons of Nickel equivalent (with an average grade ≥ 0,3%) have been explored, and some of them now is mining. As a result of our research, the complex of indicators and criteria is suggested for predicting the occurrence, for regional exploration target selection and for regional resource evaluation of PGE and base metals. The studies are supported by the Russian Foundation for Basic Research (project nos. 13-05-12055).

  13. Ecological intereactions of reef building corals

    EPA Science Inventory

    Coral reefs are very important marine ecosystems because they support tremendous biodiversity and reefs are critical economic resources many coastal nations. Tropical reef structures are largely built by stony corals. This presentation provides background on basic coral biology t...

  14. Where we are in flotation chemistry after 70 years of research

    SciTech Connect

    Fuerstenau, D.W.

    1995-12-31

    The success of industrial flotation separations has been the design of specific chemical schemes for regulating the bulk and the surface chemistry of the system. Highlights of fundamental research on the nature of flotation reagents and their mode of action in flotation, which has been carried on for about the past 65 years, is briefly reviewed.

  15. 33 CFR 175.25 - Enforcement of State requirements for children to wear personal flotation devices.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... for children to wear personal flotation devices. 175.25 Section 175.25 Navigation and Navigable Waters... Flotation Devices 175.25 Enforcement of State requirements for children to wear personal flotation devices... of any State that has established by statute a requirement for children of a certain age to wear...

  16. 33 CFR 175.25 - Enforcement of State requirements for children to wear personal flotation devices.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... for children to wear personal flotation devices. 175.25 Section 175.25 Navigation and Navigable Waters... Flotation Devices 175.25 Enforcement of State requirements for children to wear personal flotation devices... of any State that has established by statute a requirement for children of a certain age to wear...

  17. 33 CFR 175.25 - Enforcement of State requirements for children to wear personal flotation devices.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... for children to wear personal flotation devices. 175.25 Section 175.25 Navigation and Navigable Waters... Flotation Devices 175.25 Enforcement of State requirements for children to wear personal flotation devices... of any State that has established by statute a requirement for children of a certain age to wear...

  18. 33 CFR 175.25 - Enforcement of State requirements for children to wear personal flotation devices.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... for children to wear personal flotation devices. 175.25 Section 175.25 Navigation and Navigable Waters... Flotation Devices 175.25 Enforcement of State requirements for children to wear personal flotation devices... of any State that has established by statute a requirement for children of a certain age to wear...

  19. 33 CFR 175.25 - Enforcement of State requirements for children to wear personal flotation devices.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... for children to wear personal flotation devices. 175.25 Section 175.25 Navigation and Navigable Waters... Flotation Devices 175.25 Enforcement of State requirements for children to wear personal flotation devices... of any State that has established by statute a requirement for children of a certain age to wear...

  20. Ordovician reef-hosted Jiaodingshan Mn-Co deposit and Dawashan Mn deposit, Sichuan Province, China

    USGS Publications Warehouse

    Fan, Delian; Hein, James R.; Ye, Jie

    1999-01-01

    The Jiaodingshan Mn-Co and Dawashan Mn deposits are located in the approximately 2-m thick Daduhe unit of the Wufengian strata of Late Ordovician (Ashgill) age. Paleogeographic reconstruction places the deposits at the time of their formation in a gulf between Chengdu submarine rise and the Kangdian continent. The Jiaodingshan and Dawashan deposits occur in algal-reef facies, the former in an atoll-like structure and the latter in a pinnacle reef. Ores are mainly composed of rhodochrosite, kutnahorite, hausmannite, braunite, manganosite, and bementite. Dark red, yellowish-pink, brown, green-gray, and black ores are massive, banded, laminated, spheroidal, and cryptalgal (oncolite, stromatolite, algal filaments) boundstones. Blue, green, and red algal fossils show in situ growth positions. Samples of high-grade Jiaodingshan and Dawashan ores assay as much as 66.7% MnO. Jiaodingshan Mn carbonate ores have mean contents of Ba, Co, and Pb somewhat higher than in Dawashan ores. Cobalt is widely distributed and strongly enriched in all rock types as compared to its crustal mean content. Cobalt is correlated with Cu, Ni, and MgO in both deposits and additionally with Ba and Zn in the Dawashan deposit. The ?13C(PDB) values of Mn carbonate ores (-7.8 to -16.3) indicate contributions of carbon from both seawater bicarbonate and the bacterial degradation of organic matter, the latter being 33% to 68%, assuming about -24 for the ?13C(PDB) of the organic matter. Host limestones derived carbon predominantly from seawater bicarbonate ?1313C(PDB) of +0.2 to -7). NW-trending fault zones controlled development of lithofacies, whereas NE-trending fault zones provided pathways for movement of fluids. The source of Co, Ni, and Cu was mainly from weathering of mafic and ultramafic rocks on the Kangdian continent, whereas contemporaneous volcanic eruptions were of secondary importance. The reefs were likely mineralized during early diagenesis under shallow burial. The reefs were highly porous and acted as the locus for metasomatic replacement by Mn that combined with CO2 produced during oxidation of organic matter in the zone of sulfate reduction and seawater bicarbonate. That metasomatic replacement formed the rhodochrosite ores.

  1. The modes of occurrence of rare-earths ores and the issues on their beneficiation processes

    NASA Astrophysics Data System (ADS)

    Takagi, T.

    2012-04-01

    Rare-earths (RE) ores can largely be divided into the following four types in terms of the modes of occurrence. In each type of RE ores, there are some issues on beneficiation processes, which should be resolved for their successful exploitation. 1. Fine-grained phosphates with iron oxides: This type ores are commonly found from weathered carbonatite and IOCG deposits. The former is Araxa (Brazil), Zandkopsdrift (South Africa), Mt. Weld (Australia) and Yen Phu (Vietnam), and the latter Bayan Obo (China), Vergenoeg (South Africa) and Olympic Dam (Australia). Main RE minerals are monazite, xenotime and florencite contained in the aggregates of iron oxides such as goethite, hematite and magnetite. Fluorite often occurs in the latter type ores. The phosphates and iron oxides occur commonly as very fine grains (< 10 micron meters), and thus they are not readily separated by conventional physical processing. 2. Fluorapatite veins: This type ores are found from the deposits related to alkaline igneous rocks. Nolans Bore (Australia), Palabora (South Africa) and Mushugai Khudag (Mongolia) are the examples. RE is contained mostly in fluorapatite and associated monazite. It is expected that RE can be produced as byproducts of phosphorus fertilizer. However, dissolution of fluorapatite by sulfuric acid causes the coprecipitation of RE with gypsum, which is a refractory material. 3. Silicates and niobium oxides: This type ores are found from hydrothermally altered alkaline plutonic rocks or pegmatitic veins related to alkaline magmatism. Nechalacho and Strange Lake (Canada), Kvanefjeld (Greenland), Bokan Mountain (US), Norra Karr (Sweden) and Dubbo (Australia) are the representative deposits. Main RE minerals are zircon, eudialyte, mosandrite, fergusonite and allanite. They are relatively enriched in heavy RE, and it is expected that part of RE can be produced as byproducts of zirconium. However, their acid dissolution often causes the coprecipitation of RE with silica gel, which is also a refractory material. 4. Medium- to coarse-grained carbonates: This type ores occur in less weathered carbonatite bodies. Mountain Pass (US), Maoniuping (China) and Dong Pao (Vietnam) are the representative deposits. Bastnasite is a main RE mineral. Though, the ores can readily be beneficiated by conventional flotation and dissolved by acid solution, they are always depleted in heavy RE.

  2. An observational heat budget analysis of a coral reef, Heron Reef, Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    MacKellar, Mellissa C.; McGowan, Hamish A.; Phinn, Stuart R.

    2013-03-01

    Measurements of the surface energy balance, the structure and evolution of the convective atmospheric reef layer (CARL), and local meteorology and hydrodynamics were made during June 2009 and February 2010 at Heron Reef, Australia, to establish the relative partitioning of heating within the water and atmosphere. Horizontal advection was shown to moderate temperature in the CARL and the water, having a cooling influence on the atmosphere, and providing an additional source or sink of energy to the water overlying the reef, depending on tide. The key driver of atmospheric heating was surface sensible heat flux, while heating of the reef water was primarily due to solar radiation, and thermal conduction and convection from the reef substrate. Heating and cooling processes were more defined during winter due to higher sensible and latent heat fluxes and strong diurnal evolution of the CARL. Sudden increases in water temperature were associated with inundation of warmer oceanic water during the flood tide, particularly in winter due to enhanced nocturnal cooling of water overlying the reef. Similarly, cooling of the water over the reef occurred during the ebb tide as heat was transported off the reef to the surrounding ocean. While these results are the first to shed light on the heat budget of a coral reef and overlying CARL, longer-term, systematic measurements of reef thermal budgets are needed under a range of meteorological and hydrodynamic conditions, and across various reef types to elucidate the influence on larger-scale oceanic and atmospheric processes. This is essential for understanding the role of coral reefs in tropical and sub-tropical meteorology; the physical processes that take place during coral bleaching events, and coral and algal community dynamics on coral reefs.

  3. Oceanic forcing of coral reefs.

    PubMed

    Lowe, Ryan J; Falter, James L

    2015-01-01

    Although the oceans play a fundamental role in shaping the distribution and function of coral reefs worldwide, a modern understanding of the complex interactions between ocean and reef processes is still only emerging. These dynamics are especially challenging owing to both the broad range of spatial scales (less than a meter to hundreds of kilometers) and the complex physical and biological feedbacks involved. Here, we review recent advances in our understanding of these processes, ranging from the small-scale mechanics of flow around coral communities and their influence on nutrient exchange to larger, reef-scale patterns of wave- and tide-driven circulation and their effects on reef water quality and perceived rates of metabolism. We also examine regional-scale drivers of reefs such as coastal upwelling, internal waves, and extreme disturbances such as cyclones. Our goal is to show how a wide range of ocean-driven processes ultimately shape the growth and metabolism of coral reefs. PMID:25251270

  4. Conical O-ring seal

    DOEpatents

    Chalfant, Jr., Gordon G. (North Augusta, SC)

    1984-01-01

    A shipping container for radioactive or other hazardous materials which 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.

  5. Measuring Gaps In O-Ring Seals

    NASA Technical Reports Server (NTRS)

    Johnson, Scott E.

    1990-01-01

    Technique enables measurement of leakage areas created by small obstructions in O-ring seals. With simple fixture, gaps measured directly. Compresses piece of O-ring by amount determined by spacers. Camera aimed through clear plastic top plate records depression made in O-ring by obstruction. Faster, easier, more accurate than conventional estimation.

  6. O-ring gasket test fixture

    NASA Technical Reports Server (NTRS)

    Turner, James Eric (Inventor); Mccluney, Donald Scott (Inventor)

    1991-01-01

    An apparatus is presented for testing O-ring gaskets under a variety of temperature, pressure, and dynamic loading conditions. Specifically, this apparatus has the ability to simulate a dynamic loading condition where the sealing surface in contact with the O-ring moves both away from and axially along the face of the O-ring.

  7. Nanoparticle flotation collectors III: the role of nanoparticle diameter.

    PubMed

    Yang, Songtao; Pelton, Robert; Montgomery, Miles; Cui, Yuguo

    2012-09-26

    The ability of polystyrene nanoparticles to promote glass bead flotation was measured as a function of nanoparticle diameter. In all cases, smaller nanoparticles were more effective flotation collectors, even when compared at constant nanoparticle number concentration. The superior performance of smaller particles was explained by two mechanisms, acting in parallel. First, smaller particles deposit more quickly giving more effective flotation in those cases where nanoparticle deposition kinetics is rate determining; the sensitivity of nanoparticle deposition rates to particle size was illustrated by kinetic measurements on a quartz crystal microbalance silica surface. Second, for a given coverage of nanoparticles on the glass beads, the mean distance between neighboring nanoparticle surfaces decreases with particle diameter. We propose that the expansion of the three phase contact line, after initial bead/bubble attachment, is favored with decreasing the distance between neighboring hydrophobic particles. PMID:22871900

  8. Intensification of flotation treatment by exposure to vibration.

    PubMed

    Ivanov, M V; Ksenofontov, B S

    2014-01-01

    In this paper, an intensification of wastewater flotation treatment by exposure to vibration is studied. Exposure to vibration results in the decrease of air bubble size, increase of air flow through the aerator and more even dispersion of air bubbles in water. This intensifies the aeration process, thus significantly improving the treatment efficiency. A multistage model of flotation kinetics has been applied in order to take into consideration the effects of vibration. The model gives a thorough explanation of the flotation process with consideration of 'air bubble - contaminant particle' aggregate formation. A large series of experiments was conducted with paint and varnish industry wastewaters. It is shown that vibroflotation results in an increase of treatment efficiency by up to three times. A comparison of the experimental data with the results of mathematical modeling is presented, showing a good correlation of theoretical and experimental results. PMID:24718333

  9. Recovery of fine-particle coal by colloid flotation

    SciTech Connect

    Rubin, A.J.; Kramer, R.J. III

    1982-04-01

    The technical feasibility of a novel flotation technique for the recovery of extremely small particles of coal from water was investigated. This approach, colloid flotation, utilizes microbubbles generated at low gas flow rates. A procedure was also developed for preparing stable and reproducible suspensions of colloidal coal as might be found in the effluents of preparation plants. Oxidation of the coal contributed to its ability to remain dispersed for long periods of time over a broad pH range. Several parameters controlling flotation were examined including collector type and concentration, pH, gas flow rate, and frother dose in batch, bench-scale studies. Recovery attempts with an anionic collector were not successful. The coal was removed very effectively, however, using a cationic surfactant collector. Rates of removal were greatest at low pH and depended on gas flow rate as well as the collector and frother doses. The results were related to the electrophoretic mobility of the coal.

  10. Selective flotation of PVC using gelatin and lignin alkali.

    PubMed

    Yenial, Unzile; Kangal, Olga; Gney, Ali

    2013-06-01

    Recycling has become one of the most important issues as a result of increasing waste mass in present day. This is especially important for polymer wastes as they are hard to degenerate in nature. Today, most of the practical methods used for the recycling of waste mass, such as hand sorting, gravity separation, etc., cannot be performed successfully owing to close densities of polymers. Froth flotation can be used successfully and economically for this purpose. The main objective of this study was to investigate the effect of plasticizer reagents and the success of froth flotation at plastic recycling. In this study, lignin alkali and gelatin were used as plasticizer reagents. The effect of these reagents was searched with the parameters of pH, concentration, conditioning and flotation time. In the case of post-consumed polyethylene terephthalate and polyvinyl chloride (PVC), 98.9% purity of PVC was obtained at optimum conditions. PMID:23439876

  11. Development of the MC3462A pyrotechnic - propellant actuated reefing line cutter

    SciTech Connect

    Craig, J.R.

    1982-06-01

    A pyrotechnic-propellant actuated reefing line cutter was developed to sever a 60 kN loaded Kevlar parachute reefing line cord. Dereefing occurs after a time interval of approximately 0.875 second which is provided by an electronic timer module that is an integral part of the cutter. Other design features include a hermetically sealed actuator which is threaded and O-ring sealed into the body, a stainless steel solid cylindrical cutter blade having an attached elastomer obturator that provides a reliable dynamic gas seal throughout the blade stroke and teflon inserts having a semi-circular configuration which are used to center and shroud the reefing line of the design. Variation in the average function time for the cutter is less than 4% at temperature extremes of -55/sup 0/C and 80/sup 0/C. Average depth of penetration of the blade into the aluminum anvil of the cutter is 2 mm.

  12. Physical exploration for uranium during 1951 in the Silver Reef district, Washington County, Utah

    USGS Publications Warehouse

    Stugard, Frederick, Jr.

    1953-01-01

    During 1951 a joint exploration program of the most promising uraniferous areas in the Silver Reef district was made by the U.S. Geological Survey and the u.S. Atomic Energy Commission. A U.S. Bureau of Mines drill crew, on contract to the Atomic Energy Commission, did 2,450 feet of diamond drilling under the geological supervision of the U.S. Geological Survey. The purpose of the drilling was to delineate broadly the favorable ground for commercial development of the uranium depostis. Ten drill holes were located around Pumpkin Point, which is the northeastern end of Buckeye Reef, to probe for extensions of small ore shootsmined on the Point in fine-grained sandstones of the Chinle formation. Three additional holes were located around teh Tecumseh Hill to prbe for extensions of the small showings of uranium-bearing rocks of Buckeye Reef.

  13. Digital reef rugosity estimates coral reef habitat complexity.

    PubMed

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

    Ecological habitats with greater structural complexity contain more species due to increased niche diversity. This is especially apparent on coral reefs where individual coral colonies aggregate to give a reef its morphology, species zonation, and three dimensionality. Structural complexity is classically measured with a reef rugosity index, which is the ratio of a straight line transect to the distance a flexible chain of equal length travels when draped over the reef substrate; yet, other techniques from visual categories to remote sensing have been used to characterize structural complexity at scales from microhabitats to reefscapes. Reef-scale methods either lack quantitative precision or are too time consuming to be routinely practical, while remotely sensed indices are mismatched to the finer scale morphology of coral colonies and reef habitats. In this communication a new digital technique, Digital Reef Rugosity (DRR) is described which utilizes a self-contained water level gauge enabling a diver to quickly and accurately characterize rugosity with non-invasive millimeter scale measurements of coral reef surface height at decimeter intervals along meter scale transects. The precise measurements require very little post-processing and are easily imported into a spreadsheet for statistical analyses and modeling. To assess its applicability we investigated the relationship between DRR and fish community structure at four coral reef sites on Menjangan Island off the northwest corner of Bali, Indonesia and one on mainland Bali to the west of Menjangan Island; our findings show a positive relationship between DRR and fish diversity. Since structural complexity drives key ecological processes on coral reefs, we consider that DRR may become a useful quantitative community-level descriptor to characterize reef complexity. PMID:23437380

  14. Digital Reef Rugosity Estimates Coral Reef Habitat Complexity

    PubMed Central

    Dustan, Phillip; Doherty, Orla; Pardede, Shinta

    2013-01-01

    Ecological habitats with greater structural complexity contain more species due to increased niche diversity. This is especially apparent on coral reefs where individual coral colonies aggregate to give a reef its morphology, species zonation, and three dimensionality. Structural complexity is classically measured with a reef rugosity index, which is the ratio of a straight line transect to the distance a flexible chain of equal length travels when draped over the reef substrate; yet, other techniques from visual categories to remote sensing have been used to characterize structural complexity at scales from microhabitats to reefscapes. Reef-scale methods either lack quantitative precision or are too time consuming to be routinely practical, while remotely sensed indices are mismatched to the finer scale morphology of coral colonies and reef habitats. In this communication a new digital technique, Digital Reef Rugosity (DRR) is described which utilizes a self-contained water level gauge enabling a diver to quickly and accurately characterize rugosity with non-invasive millimeter scale measurements of coral reef surface height at decimeter intervals along meter scale transects. The precise measurements require very little post-processing and are easily imported into a spreadsheet for statistical analyses and modeling. To assess its applicability we investigated the relationship between DRR and fish community structure at four coral reef sites on Menjangan Island off the northwest corner of Bali, Indonesia and one on mainland Bali to the west of Menjangan Island; our findings show a positive relationship between DRR and fish diversity. Since structural complexity drives key ecological processes on coral reefs, we consider that DRR may become a useful quantitative community-level descriptor to characterize reef complexity. PMID:23437380

  15. Electrokinetic properties of hydroxyapatite under flotation conditions.

    PubMed

    Vucini?, Dusica R; Radulovi?, Dragan S; Deusi?, Slaven D

    2010-03-01

    The effect of calcite supernatant, calcium, and carbonate ions on the hydroxyapatite (HA) zeta potential without and in the presence of sodium oleate (1x10(-4) mol L(-1)) was examined within the pH range from 4 to 12. The interpretation of results was based on the HA surface and oleate solution chemistry, and on some floatability tests. HA, with different positive and negative surface sites formed depending on its solubility and pH, had a negative zeta potential over the whole pH range. This mineral is not naturally floatable (flotation recovery, 5%9.3. The HA surface is less negatively charged in calcite supernatant than in water from pH 6.6 to 9.2 due to the adsorption on HA negative surface active centers ([triple bond]HPO(4)(-) and [triple bond]PO(4)(2-)) of the Ca(2+), and CaOH(+) ions (present in the calcite supernatant), producing more surface sites [triple bond]HPO(4)Ca(+), [triple bond]PO(4)Ca, [triple bond]HPO(4)CaOH, and [triple bond]PO(4)(-) CaOH, and new centers [triple bond]HPO(4)CaHCO(3) and [triple bond]PO(4)(-) CaHCO(3). In the presence of 1x10(-3) mol L(-1) CaCl(2), the HA sample has positive zeta potential, the same as calcite from the same deposit, up to IEP at pH 11.25. Carbonate ions (1x10(-3) mol L(-1) Na(2)CO(3)) do not affect the HA zeta potential. However, a possible process can be the ion-exchange reaction between bicarbonate (or carbonate) and some anion from the surface sites formed on HA. The obtained values of the HA zeta potential with the collector (1x10(-4) mol L(-1) Na-oleate) added into hydroxyapatite/calcite supernatant suspensions corroborate the weak chemisorption of Ol(-) and H(Ol)(2)(-). The likely processes in this system also are the ion-exchange reactions on [triple bond]HPO(4)CaOH and [triple bond]PO(4)(-) CaOH, [triple bond]HPO(4)CaHCO(3) and [triple bond]PO(4)(-) CaHCO(3) between oleate ion and surface hydroxyl and bicarbonate ions, surface and bulk precipitations of calcium oleate, Ca(Ol)(2), and the surface and bulk precipitations of Ca[H(Ol)(2)(-)](2) over the pH range from 7 to 9. Calcite supernatant does not influence natural floatability of the mineral. However, calcite supernatant depresses the hydroxyapatite flotation in the presence of 1x10(-4) mol L(-1) Na-oleate (pH 9, R approximately 50%), a likely result of the weak chemisorption due to the steric effect of heterogeneous HA surface formed in calcite supernatant, Ca(Ol)(2) and Ca[H(Ol)(2)(-)](2) surface and bulk precipitations. PMID:20018290

  16. Relative flotation response of zinc sulfide: Mineral and precipitate

    SciTech Connect

    Rao, S.R.; Finch, J.A.; Zhou, Z.; Xu, Z.

    1998-04-01

    Flotation continues to extend to nonmineral applications, including recycling of materials, soil remediation, and effluent treatment. A study has been conducted to compare the floatability of fine zinc sulfide (ZnS) precipitates and sphalerite particles. The floatability of the precipitates was significantly poorer compared to sphalerite particles when xanthate was used as the collector. The floatability was improved by using dodecylamine as the collector, and the difference in floatability between the precipitates was further improved significantly by incorporating a hydrodynamic cavitation tube in a conventional (mechanical) flotation cell. The improved kinetics was attributed to in-situ gas nucleation on the precipitates.

  17. A mathematical model for the flotation of waste activated sludge.

    PubMed

    Fujisaki, K; El-Zahar, M

    2002-01-01

    A mathematical model that describes a batch flotation process is presented. The model employed a similar method to the hindered settling of flocculated material. This idea is based on our experimental results that the time growth curves of separated liquor zone showed a similar character to the settling curve of flocculated material, when the vertical axis reversed. In this model, it is also assumed that the gas phase and solid phase have the same movement, that is microbubbles and solid sludge particles joined to form aggregated floc. By comparing the numerical prediction with experimental data, the usefulness of the model is confirmed and some examples of flotation simulation are demonstrated. PMID:12523755

  18. Coral reefs on the edge? Carbon chemistry on inshore reefs of the great barrier reef.

    PubMed

    Uthicke, Sven; Furnas, Miles; Lnborg, Christian

    2014-01-01

    While increasing atmospheric carbon dioxide (CO2) concentration alters global water chemistry (Ocean Acidification; OA), the degree of changes vary on local and regional spatial scales. Inshore fringing coral reefs of the Great Barrier Reef (GBR) are subjected to a variety of local pressures, and some sites may already be marginal habitats for corals. The spatial and temporal variation in directly measured parameters: Total Alkalinity (TA) and dissolved inorganic carbon (DIC) concentration, and derived parameters: partial pressure of CO2 (pCO2); pH and aragonite saturation state (?ar) were measured at 14 inshore reefs over a two year period in the GBR region. Total Alkalinity varied between 2069 and 2364 mol kg-1 and DIC concentrations ranged from 1846 to 2099 mol kg-1. This resulted in pCO2 concentrations from 340 to 554 atm, with higher values during the wet seasons and pCO2 on inshore reefs distinctly above atmospheric values. However, due to temperature effects, ?ar was not further reduced in the wet season. Aragonite saturation on inshore reefs was consistently lower and pCO2 higher than on GBR reefs further offshore. Thermodynamic effects contribute to this, and anthropogenic runoff may also contribute by altering productivity (P), respiration (R) and P/R ratios. Compared to surveys 18 and 30 years ago, pCO2 on GBR mid- and outer-shelf reefs has risen at the same rate as atmospheric values (?1.7 atm yr-1) over 30 years. By contrast, values on inshore reefs have increased at 2.5 to 3 times higher rates. Thus, pCO2 levels on inshore reefs have disproportionately increased compared to atmospheric levels. Our study suggests that inshore GBR reefs are more vulnerable to OA and have less buffering capacity compared to offshore reefs. This may be caused by anthropogenically induced trophic changes in the water column and benthos of inshore reefs subjected to land runoff. PMID:25295864

  19. A Study of the Optimal Model of the Flotation Kinetics of Copper Slag from Copper Mine BOR

    NASA Astrophysics Data System (ADS)

    Stanojlovi?, Rodoljub D.; Sokolovi?, Jovica M.

    2014-10-01

    In this study the effect of mixtures of copper slag and flotation tailings from copper mine Bor, Serbia on the flotation results of copper recovery and flotation kinetics parameters in a batch flotation cell has been investigated. By simultaneous adding old flotation tailings in the ball mill at the rate of 9%, it is possible to increase copper recovery for about 20%. These results are compared with obtained copper recovery of pure copper slag. The results of batch flotation test were fitted by MatLab software for modeling the first-order flotation kinetics in order to determine kinetics parameters and define an optimal model of the flotation kinetics. Six kinetic models are tested on the batch flotation copper recovery against flotation time. All models showed good correlation, however the modified Kelsall model provided the best fit.

  20. Method for enhancing selectivity and recovery in the fractional flotation of particles in a flotation column

    DOEpatents

    Klunder, Edgar B. (Bethel Park, PA)

    2011-08-09

    The method relates to particle separation from a feed stream. The feed stream is injected directly into the froth zone of a vertical flotation column in the presence of a counter-current reflux stream. A froth breaker generates a reflux stream and a concentrate stream, and the reflux stream is injected into the froth zone to mix with the interstitial liquid between bubbles in the froth zone. Counter-current flow between the plurality of bubbles and the interstitial liquid facilitates the attachment of higher hydrophobicity particles to bubble surfaces as lower hydrophobicity particles detach. The height of the feed stream injection and the reflux ratio may be varied in order to optimize the concentrate or tailing stream recoveries desired based on existing operating conditions.

  1. Oil removal from produced water by conjugation of flotation and photo-Fenton processes.

    PubMed

    da Silva, Syllos Santos; Chiavone-Filho, Osvaldo; de Barros Neto, Eduardo Lins; Foletto, Edson Luiz

    2015-01-01

    The present work investigates the conjugation of flotation and photo-Fenton techniques on oil removal performance from oilfield produced water. The experiments were conducted in a column flotation and annular lamp reactor for induced air flotation and photodegradation steps, respectively. A nonionic surfactant was used as a flotation agent. The flotation experimental data were analyzed in terms of a first-order kinetic rate model. Two experimental designs were employed to evaluate the oil removal efficiency: fractional experimental design and central composite rotational design (CCRD). Overall oil removal of 99% was reached in the optimum experimental condition after 10 min of flotation followed by 45 min of photo-Fenton. The results of the conjugation of induced air flotation and photo-Fenton processes allowed meeting the wastewater limits established by the legislations for disposal. PMID:25239685

  2. Hydrocarbon-oil encapsulated bubble flotation of fine coal using 3-in. ID flotation column. Technical progress report for the eleventh quarter, April 1--June 30, 1993

    SciTech Connect

    Peng, F.F.

    1996-05-01

    There are four modes of the collector dispersion techniques. They are (1) direct liquid additions and stirring, (2) ultrasonic energy collector dispersion, (3) atomized collector dispersion, and (4) gasified collector transported in air stream. Among those collector dispersion techniques, the technique using the gasified collector transported in air phase can be used to enhance the flotation performance with substantial reduction in collector usage and selectivity, compared to the flotation using direct liquid addition (and mechanical agitation) technique. In this phase of study, two modes of collector addition techniques including gasified collector transported in gas phase and direct collector addition techniques were applied in the column flotation to demonstrate the selectivity of utilizing the hydrocarbon-oil encapsulated air bubbles in the fine coal flotation process. The 1-in. ID flotation column was used to scale-up to 3-in. ID flotation column. The initial starting point to operate the 3-in ID flotation column were determined using both 1-in. and 3-in. flotation columns based on the three phases of work plans and experiment design. A 3-in. flotation column was used to evaluate two modes of collector dispersion and addition techniques on the recovery and grade of fine coals using various ranks of coal.

  3. Black reefs: iron-induced phase shifts on coral reefs.

    PubMed

    Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

    2012-03-01

    The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to <10% on black reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75 km(2)). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions. PMID:21881615

  4. Black reefs: iron-induced phase shifts on coral reefs

    PubMed Central

    Kelly, Linda Wegley; Barott, Katie L; Dinsdale, Elizabeth; Friedlander, Alan M; Nosrat, Bahador; Obura, David; Sala, Enric; Sandin, Stuart A; Smith, Jennifer E; Vermeij, Mark J A; Williams, Gareth J; Willner, Dana; Rohwer, Forest

    2012-01-01

    The Line Islands are calcium carbonate coral reef platforms located in iron-poor regions of the central Pacific. Natural terrestrial run-off of iron is non-existent and aerial deposition is extremely low. However, a number of ship groundings have occurred on these atolls. The reefs surrounding the shipwreck debris are characterized by high benthic cover of turf algae, macroalgae, cyanobacterial mats and corallimorphs, as well as particulate-laden, cloudy water. These sites also have very low coral and crustose coralline algal cover and are call black reefs because of the dark-colored benthic community and reduced clarity of the overlying water column. Here we use a combination of benthic surveys, chemistry, metagenomics and microcosms to investigate if and how shipwrecks initiate and maintain black reefs. Comparative surveys show that the live coral cover was reduced from 40 to 60% to <10% on black reefs on Millennium, Tabuaeran and Kingman. These three sites are relatively large (>0.75?km2). The phase shift occurs rapidly; the Kingman black reef formed within 3 years of the ship grounding. Iron concentrations in algae tissue from the Millennium black reef site were six times higher than in algae collected from reference sites. Metagenomic sequencing of the Millennium Atoll black reef-associated microbial community was enriched in iron-associated virulence genes and known pathogens. Microcosm experiments showed that corals were killed by black reef rubble through microbial activity. Together these results demonstrate that shipwrecks and their associated iron pose significant threats to coral reefs in iron-limited regions. PMID:21881615

  5. Sandstone Cliffs in Capitol Reef

    USGS Multimedia Gallery

    Sandstone cliffs in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  6. Sandstone Cliff in Capitol Reef

    USGS Multimedia Gallery

    A sandstone cliff in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  7. Sandstone Monolith in Capitol Reef

    USGS Multimedia Gallery

    A sandstone monolith in Capitol Reef National Park. Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  8. Coral reefs and carbon dioxide

    SciTech Connect

    Buddemeier, R.W.

    1996-03-01

    This commentary argues the conclusion from a previous article, which investigates diurnal changes in carbon dioxide partial pressure and community metabolism on coral reefs, that coral `reefs might serve as a sink, not a source, for atmospheric carbon dioxide.` Commentaries from two groups are given along with the response by the original authors, Kayanne et al. 27 refs.

  9. Method for beneficiating coal ore

    SciTech Connect

    Irons, S.D.

    1983-03-15

    A new heavy liquid parting medium comprising an emulsion of water and a substantially water immiscible heavy parting liquid for use in beneficiating ores by gravity separations such as sink -float processes. The specific gravity of the emulsion parting medium can be adjusted by proportioning the relative amounts of water and the substantially water immiscible heavy liquid. Asmined coal is beneficiated using a water-trichlorofluoromethane emulsion as the parting medium in a sink-float separation process.

  10. Confronting the coral reef crisis.

    PubMed

    Bellwood, D R; Hughes, T P; Folke, C; Nystrm, M

    2004-06-24

    The worldwide decline of coral reefs calls for an urgent reassessment of current management practices. Confronting large-scale crises requires a major scaling-up of management efforts based on an improved understanding of the ecological processes that underlie reef resilience. Managing for improved resilience, incorporating the role of human activity in shaping ecosystems, provides a basis for coping with uncertainty, future changes and ecological surprises. Here we review the ecological roles of critical functional groups (for both corals and reef fishes) that are fundamental to understanding resilience and avoiding phase shifts from coral dominance to less desirable, degraded ecosystems. We identify striking biogeographic differences in the species richness and composition of functional groups, which highlight the vulnerability of Caribbean reef ecosystems. These findings have profound implications for restoration of degraded reefs, management of fisheries, and the focus on marine protected areas and biodiversity hotspots as priorities for conservation. PMID:15215854

  11. Surface chemistry control for selective fossil resin flotation

    DOEpatents

    Miller, Jan D.; Yi, Ye; Yu, Qiang

    1994-01-01

    A froth flotation method is disclosed for separating fine particles of fossil resin from by use of frothing reagents which include an aliphatic organic compound having a polar group and containing not more than four carbon atoms. Butanol is an effective frothing reagent in this method.

  12. Surface chemistry control for selective fossil resin flotation

    DOEpatents

    Miller, J.D.; Yi, Y.; Yu, Q.

    1994-06-07

    A froth flotation method is disclosed for separating fine particles of fossil resin by use of frothing reagents which include an aliphatic organic compound having a polar group and containing not more than four carbon atoms. Butanol is an effective frothing reagent in this method. 12 figs.

  13. Flotation of fine coal with different volatility in China

    SciTech Connect

    Guo, M.X.; Hui, W.D.; An, Z.; Ren, Z.M.; Wang, Q.F.; Dai, Z.; Xiao, Z.Q.; Cui, Y.B.; Zhang, X.J.

    1997-12-31

    This paper contains three parts. The first part interprets the surface hydrophobicity and theoretical floatability of different rank coals from the organic molecular component point of view. The theoretical floatability between bituminous and anthracite is solved by the molecular theory. The second part describes a study of the interactive energy between hydrocarbon oil and coal particle using DLVO theory showing that the controlling factor in determining the repulsive energy barrier preventing oil from wetting and spreading on the coal surface is the same sign charge and Zeta potential. Some surfactants to promote the interaction of hydrocarbon oil and coal surface were investigated. The batch tests show a new flotation promoter having a higher efficiency and performance. A discussion is centered on the relationship between the floatabilities of coals with different volatile matter and the character of the new reagent. A molecular theory for the explanation of the interaction mechanism of the flotation reagent on coal surface was summarized. A survey of four coal preparation plants (Xiqu, Malan, Taiyuan and Tianzhuang) in Shanxi and Henan provinces was introduced. The flotation performance of coal with different volatility using commercial flotation cells in the above mentioned plants was tested.

  14. 14 CFR 121.340 - Emergency flotation means.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 3 2011-01-01 2011-01-01 false Emergency flotation means. 121.340 Section 121.340 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  15. Frogmen on Apollo command module boilerplate flotation collar during recovery

    NASA Technical Reports Server (NTRS)

    1966-01-01

    Apollo command module boilerplate floats in the Atlantic Ocean during a practice recovery exercise. Frogmen in a liferaft and on the flotation collar secure the command module boilerplate for hoisting onto a nearby recovery ship. The exercise was conducted in preparation for the forthcoming Apollo-Saturn 201 (AS-201) mission.

  16. 14 CFR 121.340 - Emergency flotation means.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 3 2013-01-01 2013-01-01 false Emergency flotation means. 121.340 Section 121.340 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  17. The influence of frother structure on industrial coal flotation

    SciTech Connect

    Klimpel, R.R.

    1995-10-01

    This paper summarizes the author`s laboratory and industrial experience sin designing and evaluating frothers for optimal coal flotation circuit performance. The key variables discussed are particle size distribution, hydrocarbon addition rate, frother chemical structure, and frother dosage. A number of detailed examples will be used to illustrate the important rate/recovery/selectivity interactions that can occur.

  18. A neural network controller of a flotation process

    SciTech Connect

    Durao, F.; Cortez, L.

    1995-12-31

    The dynamic control of a froth flotation section is simulated through a neural network feedback controller, trained in order to stabilize the concentrate metal grade and recovery by applying random step changes to the feed metal grade. The results of the application example show that this controller seems to be sufficiently robust and a good alternative to handle a non-linear process.

  19. 14 CFR 121.340 - Emergency flotation means.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 3 2012-01-01 2012-01-01 false Emergency flotation means. 121.340 Section 121.340 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  20. REMOVAL OF HUMICSUBSTANCES AND ALGAE BY DISSOLVED AIR FLOTATION

    EPA Science Inventory

    Dissolved air flotation (DAF) is used in place of conventional gravity settling as a means to separate low density floc particles from water. The following objectives were: (1) to compare DAF to conventional water treatment of coagulation-flocculation followed by gravity settling...

  1. 21 CFR 880.5550 - Alternating pressure air flotation mattress.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Alternating pressure air flotation mattress. 880.5550 Section 880.5550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES GENERAL HOSPITAL AND PERSONAL USE DEVICES General Hospital and Personal Use Therapeutic Devices ...

  2. Navy frogmen attach flotation collar to Apollo 7 command module

    NASA Technical Reports Server (NTRS)

    1968-01-01

    U.S. Navy frogmen attach a flotation collar to the Apollo 7 command module during recovery operations in the Atlantic. The Apollo 7 spacecraft splashed down at 7:11 a.m., October 22, 1968, approximately 200 nautical miles south-southwest of Bermuda.

  3. The effect of coal desulfurization on flotation through ultrasonic treatment

    SciTech Connect

    Hu Jun; Chen Jianqi

    1997-12-31

    This paper carries out a study on the influence of ultrasonic treatment upon the changes of these aspects: pulp particle granularity, dissolving oxygen, pulp pH, surface potential (x), pulp potential (Eh) and conductivity rate, through the introduction of primary application and functional mechanism of ultrasonic wave such as ultrasonic comminution, ultrasonic cleaning and ultrasonic atomization. The effect of ultrasonic pretreatment on the size composition of the feeds and the floatability of coal and pyrite is examined. The tests affected the size composition of raw coal distinctively and caused the removal of sulfur from coals. It has been found that ultrasonic pretreatment of slurry enhances the differences in physico-chemical surface properties of coal and pyrite. In this case it is possible to obtain low-sulfur coals from high-sulfur coals. This may be explained by the different effects of ultrasonic vibrations on coal and pyrite which cause some improvement of the selectivity of their flotation separation. According to the authors` research, it explores the feasibility of flotation desulfurization by means of ultrasonic reinforcement, and puts forward that ultrasonic treatment of a slurry under the appropriate period of time, sonic frequency and energy density, along with appropriate flotation process and coal pyrite depression method, can achieve the best effect of flotation desulfurization. It offers a new method or means to gain abstraction of the clean coal.

  4. High-efficiency flotation of coarse and fine coal

    SciTech Connect

    Atkinson, B.W.; Conway, C.J.; Jameson, G.J.

    1995-10-01

    The flotation of coal in the fine and coarse particle size ranges presents particular problems. Fine or ultra-fine coal less than 100 microns presents a challenge to conventional flotation machines because the rate of capture of the coal particles can be very low, so longer residence times are needed. Also, conventional mechanical cells are not normally designed with froth properties in mind. Froth drainage may be inadequate, leading to excessive entrainment of ash. The upper limit of flotation of coal is normally put at about 500 {micro}m (30 mesh). It appears that, in mechanical cells, coarser particles tend to be torn away from bubbles in the turbulent environment created by the impeller. In this paper, results are presented from plant trials of a high-intensity flotation column of novel design, namely the Jameson cell. Extensive trials have been conducted on coal slurries with a top size of around 1 mm. Size-by size analysis shows that it is possible to achieve high yields of low ash product over the whole particle size range.

  5. 14 CFR 121.340 - Emergency flotation means.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 3 2014-01-01 2014-01-01 false Emergency flotation means. 121.340 Section 121.340 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  6. 14 CFR 121.340 - Emergency flotation means.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 3 2010-01-01 2010-01-01 false Emergency flotation means. 121.340 Section 121.340 Aeronautics and Space FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION (CONTINUED) AIR CARRIERS AND OPERATORS FOR COMPENSATION OR HIRE: CERTIFICATION AND OPERATIONS OPERATING REQUIREMENTS: DOMESTIC, FLAG, AND...

  7. 21 CFR 890.5170 - Powered flotation therapy bed.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 21 Food and Drugs 8 2013-04-01 2013-04-01 false Powered flotation therapy bed. 890.5170 Section 890.5170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  8. 21 CFR 890.5170 - Powered flotation therapy bed.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 8 2014-04-01 2014-04-01 false Powered flotation therapy bed. 890.5170 Section 890.5170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  9. 21 CFR 890.5170 - Powered flotation therapy bed.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Powered flotation therapy bed. 890.5170 Section 890.5170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  10. 21 CFR 890.5170 - Powered flotation therapy bed.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Powered flotation therapy bed. 890.5170 Section 890.5170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  11. 21 CFR 890.5170 - Powered flotation therapy bed.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 21 Food and Drugs 8 2012-04-01 2012-04-01 false Powered flotation therapy bed. 890.5170 Section 890.5170 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES PHYSICAL MEDICINE DEVICES Physical Medicine Therapeutic Devices §...

  12. Micro-agglomerate flotation for deep cleaning of coal

    SciTech Connect

    Chander, S.; Hogg, R.

    1993-04-01

    We are investigating the use of a hybrid process, Micro-agglomerate flotation, which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 [mu]m in size) rather than individual coal particles (1--10 [mu]m) the problems of froth overload and water/mineral carryover should be significantly alleviated.Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale. In principle, it should be possible to achieve both high selectivity and high yield at reasonable cost. The process requires only conventional, off-the-shelf equipment and reagent usage (oil, surfactants, etc.) should be small. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response.

  13. Micro-agglomerate flotation for deep cleaning of coal

    SciTech Connect

    Chander, S.; Hogg, R.

    1993-01-01

    We are investigating the use of a hybrid process - Micro-agglomerate flotation - which is a combination of oil-agglomeration and froth flotation. The basic concept is to use small quantities of oil to promote the formation of dense micro-agglomerates with minimal entrapment of water and mineral particles, and to use froth flotation to extract these micro-agglomerates from the water/dispersed-mineral phase. Since the floating units are agglomerates (about 30--50 [mu]m in size) rather than individual coal particles (1--10 [mu]m) the problems of froth overload and water/mineral carryover should be significantly alleviated. Micro-agglomerate flotation has considerable potential for the practical deep cleaning of coal on a commercial scale. In principle, it should be possible to achieve both high selectivity and high yield at reasonable cost. The process requires only conventional, off-the-shelf equipment and reagent usage (oil, surfactants, etc.) should be small. There are, however, complications. The process involves at least five phases: two or more solids (coal and mineral), two liquids (oil and water) and one gas (air). It is necessary to maintain precise control over the chemistry of the liquid phases in order to promote the interfacial reactions and interactions between phases necessary to ensure selectivity. Kinetics as well as thermodynamic factors may be critical in determining overall system response.

  14. Engineering development of advanced froth flotation. Volume 2, Final report

    SciTech Connect

    Ferris, D.D.; Bencho, J.R.; Torak, E.R.

    1995-03-01

    This report is an account of findings related to the Engineering and Development of Advanced Froth Flotation project. The results from benchscale and proof-of-concept (POC) level testing are presented and the important results from this testing are used to refine a conceptual design and cost estimate for a 20 TPH Semi-Works Facility incorporating the final proposed technology.

  15. Coal surface control for advanced fine coal flotation

    SciTech Connect

    Fuerstenau, D.W.; Sastry, K.V.S.; Hanson, J.S.; Harris, G.; Sotillo, F.; Diao, J. ); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. ); Hu, Weibai; Zou, Y.; Chen, W. ); Choudhry, V.; Sehgal, R.; Ghosh, A. )

    1990-08-15

    The primary objective of this research project is to develop advanced flotation methods for coal cleaning in order to achieve near total pyritic-sulfur removal at 90% Btu recovery, using coal samples procured from six major US coal seams. Concomitantly, the ash content of these coals is to be reduced to 6% or less. Work this quarter concentrated on the following: washability studies, which included particle size distribution of the washability samples, and chemical analysis of washability test samples; characterization studies of induction time measurements, correlation between yield, combustible-material recovery (CMR), and heating-value recovery (HVR), and QA/QC for standard flotation tests and coal analyses; surface modification and control including testing of surface-modifying reagents, restoration of hydrophobicity to lab-oxidized coals, pH effects on coal flotation, and depression of pyritic sulfur in which pyrite depression with calcium cyanide and pyrite depression with xanthated reagents was investigated; flotation optimization and circuitry included staged reagent addition, cleaning and scavenging, and scavenging and middling recycling. Weathering studies are also discussed. 19 figs., 28 tabs.

  16. Measuring turbulence in a flotation cell using electrical resistance tomography

    NASA Astrophysics Data System (ADS)

    Meng, Jun; Xie, Weiguo; Runge, Kym; Bradshaw, Dee

    2015-11-01

    Measuring turbulence in an industrial flotation environment has long been problematic due to the opaque, aggressive, and abrasive three-phase environment in a flotation cell. One of the promising measurement techniques is electrical resistance tomography (ERT). By measuring the conductivity distribution across a measurement area, ERT has been adopted by many researchers to monitor and investigate many processes involving multiphase flows. In the research outlined in this paper, a compact ERT probe was built and then used to measure the conductivity distribution within a 60 l flotation cell operated with water and air. Two approaches were then developed to process the ERT data and estimate turbulence-related parameters. One is a conductivity variance method and the other is based on the Green-Kubo relations. Both rely on and use the fluctuation in the ERT measurement caused by bubbles moving through the measurement area changing the density of the fluid. The results from both approaches were validated by comparing the results produced by the ERT probe in a 60l flotation cell operated at different air rates and impeller speeds to that measured using an alternative turbulence measurement device. The second approach is considered superior to the first as the first requires the development of auxiliary information which would not usually be known for a new system.

  17. Selective flotation of fossil resin from western coal

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-03-20

    The test program has demonstrated that: (1) technically, the new flotation technologies discovered at the University of Utah and then improved upon by Advanced Processing Technologies, Inc. provide a highly efficient means to selectively recover fossil resin from coal. The proof-of-concept continuous flotation circuit resulted in fossil resin recovery with the same separation efficiency as was obtained from laboratory bench-scale testing (more than 80% recovery at about 80% concentrate grade); and (2) economically, the selective flotation process has been shown to be sufficiently profitable to justify the development of a fossil resin industry based on this new flotation process. The proof-of-concept testing has resulted in significant interest from several coal mining companies and has sparked the desire of local and state government to establish a fossil resin industry in the Wasatch Plateau coal field. In this view, the results from the current proof-of-concept testing program have been successful. This special report provides theoretical and analytical data on some surface chemistry work pertinent to fossil resin characterization, and other efforts carried out during the past months.

  18. Innovations in the design of super-large flotation cells

    SciTech Connect

    Lawrence, G.A.

    1995-12-31

    A new super-large 100 m{sup 3} (3,500 ft{sup 3}) pneumatic mechanical flotation cell is now available to meet today`s mineral processing challenges. Several innovative design concepts represent a marked departure from conventional flotation cell designs. The radial discharge from the pump action rotor and the overhung vane type stator is contained in a conical bottom round tank with no dead corners. Peripheral launders collect froth overflowing the entire circumference of the tank and these launders are of a hexagonal design permitting cells to be nested together in a honeycomb fashion. The mechanism drive is either a customized right angle gear reducer or a conventional Vee belt drive. Both drive systems are available with an optional variable frequency control system that permits infinite speed adjustment of the rotor in each flotation cell or group of cells. Results of side-by-side comparative testing between three major manufacturers of super-large pneumatic mechanical flotation cells are discussed. These results were obtained at a large copper concentrator in Chile during several weeks of commercial scale testing.

  19. An Advanced Control System For Fine Coal Flotation

    SciTech Connect

    G. H. Luttrell; G. T. Adel

    1998-08-25

    A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of ash content. Then, based on the economic and metallurgical performance of the circuit, variables such as collector dosage, frother dosage, and pulp level are adjusted using model-based control algorithms to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the ninth quarter of this project, Task 3 (Model Building and Computer Simulation) and Task 4 (Sensor Testing) were nearly completed, and Task 6 (Equipment Procurement and Installation) was initiated. Previously, data collected from the plant sampling campaign (Task 2) were used to construct a population balance model to describe the steady-state and dynamic behavior of the flotation circuit. The details of this model were presented in the Eighth Quarterly Technical Progress Report. During the past quarter, a flotation circuit simulator was designed and used to evaluate control strategies. As a result of this work, a model-based control strategy has been conceived which will allow manipulated variables to be adjusted in response to disturbances to achieve a target incremental ash value in the last cell of the bank. This will, in effect, maximize yield at an acceptable product quality. During this same period, a video-based ash analyzer was installed on the flotation tailings stream at the Moss No. 3 preparation plant. A preliminary calibration curve was established, and data are continuing to be collected in order to improve the calibration of the analyzer.

  20. Application of Odor Sensors to Ore Sorting and Mill Feed Control

    SciTech Connect

    Michael G. Nelson

    2005-08-01

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

  1. Self-generated morphology in lagoon reefs.

    PubMed

    Blakeway, David; Hamblin, Michael G

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia's Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves-specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

  2. Self-generated morphology in lagoon reefs

    PubMed Central

    Hamblin, Michael G.

    2015-01-01

    The three-dimensional form of a coral reef develops through interactions and feedbacks between its constituent organisms and their environment. Reef morphology therefore contains a potential wealth of ecological information, accessible if the relationships between morphology and ecology can be decoded. Traditionally, reef morphology has been attributed to external controls such as substrate topography or hydrodynamic influences. Little is known about inherent reef morphology in the absence of external control. Here we use reef growth simulations, based on observations in the cellular reefs of Western Australia’s Houtman Abrolhos Islands, to show that reef morphology is fundamentally determined by the mechanical behaviour of the reef-building organisms themselves—specifically their tendency to either remain in place or to collapse. Reef-building organisms that tend to remain in place, such as massive and encrusting corals or coralline algae, produce nodular reefs, whereas those that tend to collapse, such as branching Acropora, produce cellular reefs. The purest reef growth forms arise in sheltered lagoons dominated by a single type of reef builder, as in the branching Acropora-dominated lagoons of the Abrolhos. In these situations reef morphology can be considered a phenotype of the predominant reef building organism. The capacity to infer coral type from reef morphology can potentially be used to identify and map specific coral habitat in remotely sensed images. More generally, identifying ecological mechanisms underlying other examples of self-generated reef morphology can potentially improve our understanding of present-day reef ecology, because any ecological process capable of shaping a reef will almost invariably be an important process in real time on the living reef. PMID:26175962

  3. Evolution of ore deposits on terrestrial planets

    NASA Technical Reports Server (NTRS)

    Burns, R. G.

    1991-01-01

    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.

  4. Evolution of ore deposits on terrestrial planets

    NASA Astrophysics Data System (ADS)

    Burns, R. G.

    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.

  5. Softened-Stainless-Steel O-Rings

    NASA Technical Reports Server (NTRS)

    Marquis, G. A.; Waters, William I.

    1993-01-01

    In fabrication of O-ring of new type, tube of 304 stainless steel bent around mandril into circle and welded closed into ring. Ring annealed in furnace to make it soft and highly ductile. In this condition, used as crushable, deformable O-ring seal. O-ring replacements used in variety of atmospheres and temperatures, relatively inexpensive, fabricated with minimum amount of work, amenable to one-of-a-kind production, reusable, and environmentally benign.

  6. Miocene reef corals: A review

    SciTech Connect

    Frost, S.H.

    1988-01-01

    Tectonic blockage in the Middle East of westward-flowing Tethys surface circulation during the latest Oligocene led to creation in the earliest Miocene of endemic Mediterranean, Western Atlantic-Caribbean, and Indo-Pacific realms. A great reduction in reef coral diversity from 60-80 Oligocene species to 25-35 early Miocene species occurred in the Western Atlantic-Caribbean and Mediterranean areas accompanied by a decrease in reef growth. A slower and less drastic change apparently occurred in the Indo-Pacific area. Early Miocene reef corals of the Western Atlantic-Caribbean comprise a transition between the cosmopolitan Oligocene fauna and its endemic mid-Miocene to modern counterpart. Although early Miocene reefs were dominated by a Porites-Montastrea assemblage, eastward flow of Pacific circulation brought with it ''exotic'' corals such as Coscinaraea and Pseudocolumnastrea. Also, many cosmopolitan genera persisted from the Oligocene. During the middle to late Miocene, most of the species still living on Holocene reefs evolved. As the Mediterranean basin became more restricted, there was a slow decline in reef corals from 20 - 25 species in the Aquitainian to less than five species in the Messinian. Eustatic lowstand led to the extinction of reef-building corals in the late Messinian. In the Indo-Pacific, Neogene evolution of reef corals was conservative. Excluding the Acroporidae and Seriatoporidae, most Holocene framework species had evolved by the middle Miocene. Interplay between regional tectonics and eustatic sea level changes led to extensive development of middle to late Miocene pinnacle reefs over the southwestern Pacific.

  7. NOAA's hydrolab conducts reef studies

    NASA Astrophysics Data System (ADS)

    This summer, scuba-diving scientists operating from Hydrolab, NOAA's undersea laboratory, are carrying out four experiments aimed at producing better management of coral reefs and their fishery resources. Hydrolab is located at a depth of 50 feet, near the mouth of the Salt River, off St. Croix, U.S. Virgin Islands. The lab houses four scientists for up to 2 weeks at a time, permitting them to swim out into the water to conduct research. The projects make use of both the natural coral reef near Hydrolab and the nearby artificial reef constructed for comparison studies.

  8. Age of tilted reefs, Hawaii.

    USGS Publications Warehouse

    Moore, J.G.; Campbell, J.F.

    1987-01-01

    Submerged carbonate reefs are preserved as a series of submarine terraces between Molokai and Hawaii along a 200-km span of the SE Hawaiian Ridge. Limestones from 2 of the terraces have been dated at 13 and 120 ka. Recognition that the terraces are tilted permits assignment of about a dozen terraces from 150 to 1300 m depth to 8 general reef platforms. These reefs were drowned by the combined effects of island subsidence and sea level rise at the end of successive glacial stages from 13 to 647 ka. The platforms are tilted 5 m/km SE toward the locus of volcanic centered on the island of Hawaii.-from Authors

  9. Noble metals in rocks and ores of Maysko-Lebed ore field (Mountain Shoriya)

    NASA Astrophysics Data System (ADS)

    Pshenichkin, A.; Timkin, T.; Oskina, Yu

    2015-02-01

    First the authors determined platinum and palladium in the ores and rocks of Maysk-Lebed ore deposit via stripping voltammetry. Based on research data the increased platinoid (platinum group elements) content was identified both in the source host rocks and in metasomatically altered ones in ores.

  10. An overview of oil-water separation using gas flotation systems.

    PubMed

    Saththasivam, Jayaprakash; Loganathan, Kavithaa; Sarp, Sarper

    2016-02-01

    Oil concentration levels in municipal waste water effluent streams are stringently regulated in most parts of the world. Apart from municipal waste, stricter oil/grease discharge limits are also enforced in oil and gas sectors as large volumes of produced water is being discharged to open ocean. One of the feasible, practical and established methods to remove oil substances from waste water sources is by gas flotation. In this overview, gas flotation technologies, namely dissolved and induced flotation systems, are discussed. Physico-chemical interaction between oil-water-gas during flotation is also summarized. In addition to a brief review on design advancements in flotation systems, enhancement of flotation efficiency by using pre-treatment methods, particularly coagulation-flocculation, is also presented. PMID:26408973

  11. Home Reef, South Pacific

    NASA Technical Reports Server (NTRS)

    2006-01-01

    In the South Pacific, south of Late Island along the Tofua volcanic arc in Tonga, a new volcanic island Home Reef is being re-born. The island is thought to have emerged after a volcanic eruption in mid-August that has also spewed large amounts of floating pumice into Tongan waters and sweeping across to Fiji about 350 km (220 miles) to the west of where the new island has formed. In 2004 a similar eruption created an ephemeral island about 0.5 by 1.5 km (0.3 by 0.9 miles) in size; it was no longer visible in an ASTER image acquired November 2005. This simulated natural color image shows the vegetation-covered stratovolcanic island of Late in the upper right. Home Reef is found in the lower left. The two bluish plumes are hot seawater that is laden with volcanic ash and chemicals; the larger one can be traced for more than 14 km (8.4 miles) to the east. The image was acquired October 10, 2006 and covers an area of 24.3 by 30.2 km. It is located at 18.9 degrees South latitude, 174.7 degrees west longitude.

    With its 14 spectral bands from the visible to the thermal infrared wavelength region, and its high spatial resolution of 15 to 90 meters (about 50 to 300 feet), ASTER images Earth to map and monitor the changing surface of our planet.

    ASTER is one of five Earth-observing instruments launched December 18, 1999, on NASA's Terra satellite. The instrument was built by Japan's Ministry of Economy, Trade and Industry. A joint U.S./Japan science team is responsible for validation and calibration of the instrument and the data products.

    The broad spectral coverage and high spectral resolution of ASTER provides scientists in numerous disciplines with critical information for surface mapping, and monitoring of dynamic conditions and temporal change. Example applications are: monitoring glacial advances and retreats; monitoring potentially active volcanoes; identifying crop stress; determining cloud morphology and physical properties; wetlands evaluation; thermal pollution monitoring; coral reef degradation; surface temperature mapping of soils and geology; and measuring surface heat balance.

    The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

    Size: 24.3 by 30.2 kilometers (15 by 18.6 miles) Location: 18.9 degrees South latitude, 174.7 degrees West longitude Orientation: North at top Image Data: ASTER bands 3, 2, and 1 Original Data Resolution: 15 meters (49.2 feet) Dates Acquired: October 4, 2006

  12. Toxicity of nickel ores to marine organisms.

    PubMed

    Florence, T M; Stauber, J L; Ahsanullah, M

    1994-06-01

    Queensland Nickel proposes to import New Caledonian (Ballande) and Indonesian (Gebe) nickel ores, one option being ship-to-barge transfer in Halifax Bay, North Queensland. Because small amounts of ore may be split during the unloading and transfer operations, it was important to investigate the potential impact of the spilt ore on the ecological health of the Bay. Long-term leaching of the ores with seawater showed that only nickel and chromium (VI) were released from the ores in sufficient concentrations to cause toxicity to a range of marine organisms. The soluble fractions of nickel and chromium (VI) were released from the ores within a few days. Nickel, chromium (VI) and the ore leachates showed similar toxicity to the juvenile banana prawn Penaeus merguiensis, the amphipod Allorchestes compressa and both temperature (22 degrees C) and tropical (27 degrees C) strains of the unicellular marine alga Nitzschia closterium. In a series of 30-day sub-chronic microcosm experiments, juvenile leader prawns Penaeus monodon, polychaete worms Galeolaria caespitosa and the tropical gastropod Nerita chamaeleon were all very resistant to the nickel ores, with mortality unaffected by 700 g ore per 50 l seawater. The growth rate of the leader prawns was, however, lower than that of the controls. From these data, a conservative maximum safe concentration of the nickel ores in seawater is 0.1 g l-1. The nickel ore was not highly toxic and if spilt in the quantities predicted, would not have a significant impact on the ecological health of the Bay. PMID:8029690

  13. Coral Reefs on the Edge? Carbon Chemistry on Inshore Reefs of the Great Barrier Reef

    PubMed Central

    Uthicke, Sven; Furnas, Miles; Lønborg, Christian

    2014-01-01

    While increasing atmospheric carbon dioxide (CO2) concentration alters global water chemistry (Ocean Acidification; OA), the degree of changes vary on local and regional spatial scales. Inshore fringing coral reefs of the Great Barrier Reef (GBR) are subjected to a variety of local pressures, and some sites may already be marginal habitats for corals. The spatial and temporal variation in directly measured parameters: Total Alkalinity (TA) and dissolved inorganic carbon (DIC) concentration, and derived parameters: partial pressure of CO2 (pCO2); pH and aragonite saturation state (Ωar) were measured at 14 inshore reefs over a two year period in the GBR region. Total Alkalinity varied between 2069 and 2364 µmol kg−1 and DIC concentrations ranged from 1846 to 2099 µmol kg−1. This resulted in pCO2 concentrations from 340 to 554 µatm, with higher values during the wet seasons and pCO2 on inshore reefs distinctly above atmospheric values. However, due to temperature effects, Ωar was not further reduced in the wet season. Aragonite saturation on inshore reefs was consistently lower and pCO2 higher than on GBR reefs further offshore. Thermodynamic effects contribute to this, and anthropogenic runoff may also contribute by altering productivity (P), respiration (R) and P/R ratios. Compared to surveys 18 and 30 years ago, pCO2 on GBR mid- and outer-shelf reefs has risen at the same rate as atmospheric values (∼1.7 µatm yr−1) over 30 years. By contrast, values on inshore reefs have increased at 2.5 to 3 times higher rates. Thus, pCO2 levels on inshore reefs have disproportionately increased compared to atmospheric levels. Our study suggests that inshore GBR reefs are more vulnerable to OA and have less buffering capacity compared to offshore reefs. This may be caused by anthropogenically induced trophic changes in the water column and benthos of inshore reefs subjected to land runoff. PMID:25295864

  14. Continuous Steelmaking Directly from Ore

    NASA Astrophysics Data System (ADS)

    Warner, Noel A.

    2014-12-01

    In-line continuous processing of high-grade hematite ore (crushed ore or fines) with a pure hydrogen reductant is assessed. An appraisal is made of the rate controlling mechanisms involved in the reduction of a pure layer of molten wustite being transported by floating on a molten carrier iron carbon-free medium at temperatures just in excess of the iron melting point. Published research clearly indicates that under these conditions the kinetics are principally controlled by molecular gaseous diffusion. Thus, the rate is essentially not influenced by total gas pressure above 1 atmosphere. Accordingly, on safety grounds it is recommended that high pressure should not be used for hydrogen steelmaking in the future, but the operation should be conducted close to atmospheric pressure with low pressure steam encapsulation of the plant items involved. Using hydrogen as the reductant means that sub-surface nucleation of CO bubbles cannot disrupt continuous processing. The operation is then no different to processing a normal liquid phase. The off-gases from the reduction zone of a melt circulation loop are super-clean and only contaminated with iron vapor. Accordingly, the best available technology becomes available for energy conservation without risk of non-fusible solids deposition. The net result is that the energy requirements are expected to be superior to other potential processes.

  15. Sandstone Formations in Capitol Reef

    USGS Multimedia Gallery

    Capitol Reef is primarily made up of sandstone formations within the Waterpocket Fold, monocline that extends nearly 100 miles. A monocline is a step-like fold in rock strata that can resemble an enormous wrinkle in the earth....

  16. Artificial Reefs and Ocean Dumping.

    ERIC Educational Resources Information Center

    Glueck, Richard D.

    1983-01-01

    Activities and instructional strategies for two multigrade lessons are provided. Activity objectives include describing an artificial reef (such as a sunken ocean liner) as an ecosystem, knowing animal types in the ecosystem, and describing a food web. (JN)

  17. Commencement on a Coral Reef

    ERIC Educational Resources Information Center

    Webster, Steven K.

    1973-01-01

    Describes an environmental program in which sixteen students and three biology teachers from Northfield Mount Hermon School in Massachusetts spent two weeks examining the ecology of a Caribbean reef.. (JR)

  18. On the Methodology of Nematode Extraction from Field Samples: Density Flotation Techniques

    PubMed Central

    Viglierchio, David R.; Yamashita, Tom T.

    1983-01-01

    Density flotation has been frequently used for the extraction of nematodes from field samples. Density flotation curves for four nematode species and five solutes have been prepared. The curves confirm that flotation was governed by several factors: solute density, solute osmotic activity, and physiological properties of the nematode species. Nematode viability and function can be adversely affected by improper selection of solute for density extraction of nematodes; nevertheless, some nematode species can be enriched from mixtures by density and solute selection. PMID:19295831

  19. Coral reef bleaching: ecological perspectives

    NASA Astrophysics Data System (ADS)

    Glynn, P. W.

    1993-03-01

    Coral reef bleaching, the whitening of diverse invertebrate taxa, results from the loss of symbiotic zooxanthellae and/or a reduction in photosynthetic pigment concentrations in zooxanthellae residing within the gastrodermal tissues of host animals. Of particular concern are the consequences of bleaching of large numbers of reef-building scleractinian corals and hydrocorals. Published records of coral reef bleaching events from 1870 to the present suggest that the frequency (60 major events from 1979 to 1990), scale (co-occurrence in many coral reef regions and often over the bathymetric depth range of corals) and severity (>95% mortality in some areas) of recent bleaching disturbances are unprecedented in the scientific literature. The causes of small scale, isolated bleaching events can often be explained by particular stressors (e.g., temperature, salinity, light, sedimentation, aerial exposure and pollutants), but attempts to explain large scale bleaching events in terms of possible global change (e.g., greenhouse warming, increased UV radiation flux, deteriorating ecosystem health, or some combination of the above) have not been convincing. Attempts to relate the severity and extent of large scale coral reef bleaching events to particular causes have been hampered by a lack of (a) standardized methods to assess bleaching and (b) continuous, long-term data bases of environmental conditions over the periods of interest. An effort must be made to understand the impact of bleaching on the remainder of the reef community and the long-term effects on competition, predation, symbioses, bioerosion and substrate condition, all factors that can influence coral recruitment and reef recovery. If projected rates of sea warming are realized by mid to late AD 2000, i.e. a 2°C increase in high latitude coral seas, the upper thermal tolerance limits of many reef-building corals could be exceeded. Present evidence suggests that many corals would be unable to adapt physiologically or genetically to such marked and rapid temperature increases.

  20. Estimating gold-ore mineralization potential within Topolninsk ore field (Gorny Altai)

    NASA Astrophysics Data System (ADS)

    Timkin, T.; Voroshilov, V.; Askanakova, O.; Cherkasova, T.; Chernyshov, A.; Korotchenko, T.

    2015-11-01

    Based on the results of ore and near-ore metasomatite composition analysis, the factors and indicators of gold-ore mineralization potential were proposed. Integration of the obtained data made it possible to outline magmatic, structural, and lithological factors, as well as direct and indirect indicators of gold-ore mineralization. Applying multidimensional analysis inherent to geochemical data, the spatial structure was investigated, as well as the potential mineralization was identified. Based on the developed and newly-identified mineralization, small (up to medium-sized) mineable gold-ore deposits in skarns characterized by complex geological setting was identified.

  1. In-plant testing of microbubble column flotation. Final report

    SciTech Connect

    Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Mankosa, M.J.

    1991-07-31

    Microbubble column flotation (MCF) was developed at the Virginia Center for Coal and Minerals Processing (VCCMP) for the selective recovery of fine particles. Bench-scale test work conducted at VCCMP, largely under the sponsorship of the U.S. Department of Energy (DOE), showed that the technology worked well for both coal and mineral applications. For the technology to be commercially successful, however, a full-scale demonstration of the MCF technology was deemed necessary. This report summarizes the results of work performed under the DOE project entitled ``In-plant Testing of Microbubble Column Flotation.`` The objectives of this research and development effort were to duplicate the bench-scale performance of the MCF process in a full-scale unit, to verify the scale-up procedure developed in an earlier project, and to demonstrate the applicability of the MCF technology to the coal industry.

  2. In-plant testing of microbubble column flotation

    SciTech Connect

    Yoon, R.H.; Luttrell, G.H.; Adel, G.T.; Mankosa, M.J.

    1991-07-31

    Microbubble column flotation (MCF) was developed at the Virginia Center for Coal and Minerals Processing (VCCMP) for the selective recovery of fine particles. Bench-scale test work conducted at VCCMP, largely under the sponsorship of the U.S. Department of Energy (DOE), showed that the technology worked well for both coal and mineral applications. For the technology to be commercially successful, however, a full-scale demonstration of the MCF technology was deemed necessary. This report summarizes the results of work performed under the DOE project entitled In-plant Testing of Microbubble Column Flotation.'' The objectives of this research and development effort were to duplicate the bench-scale performance of the MCF process in a full-scale unit, to verify the scale-up procedure developed in an earlier project, and to demonstrate the applicability of the MCF technology to the coal industry.

  3. Trajectory analysis and collision efficiency during microbubble flotation

    SciTech Connect

    Leppinen, D.M.

    1999-04-15

    The hydrodynamic interaction between a rising bubble and a sedimenting particle during microbubble flotation is considered. The effects of attractive van der Waals forces and attractive or repulsive electrostatic forces are included. A mathematical model is presented which is used to perform a trajectory analysis and to calculate collision efficiencies between the bubble and particle. It is shown that collision efficiencies and the nature of the bubble-particle interactions are strongly dependent on the relative strengths of the van der Waals and electrostatic forces and on the lengthscales over which these forces act. It is demonstrated that optimal operating conditions can be suggested to achieve efficient microbubble flotation by correctly accounting for the interaction of van der Waals, electrostatic, and hydrodynamic forces.

  4. Flotation classification of ultrafine particles -- A novel classification approach

    SciTech Connect

    Qiu Guanzhou; Luo Lin; Hu Yuehua; Xu Jin; Wang Dianzuo

    1995-12-31

    This paper introduces a novel classification approach named the flotation classification approach which works by controlling interactions between particles. It differs considerably from the conventional classification processes operating on mechanical forces. In the present test, the micro-bubble flotation technology is grafted onto hydro-classification. Selective aggregation and dispersion of ultrafine particles are achieved through governing the interactions in the classification process. A series of laboratory classification tests for {minus}44 gm kaolin have been conducted on a classification column. As a result, about 92% recovery for minus 2 {micro}m size fraction Kaolin in the final product is obtained. In addition, two criteria for the classification are set up. Finally, a principle of classifying and controlling the interactions between particles is discussed in terms of surface thermodynamics and hydrodynamics.

  5. Microalgae harvesting by flotation using natural saponin and chitosan.

    PubMed

    Kurniawati, H Agnes; Ismadji, Suryadi; Liu, J C

    2014-08-01

    This study aims to investigate the harvesting of microalgae by dispersed air flotation (DiAF) using natural biosurfactant saponin as the collector and chitosan as the flocculant. Two types of microalgae, Chlorella vulgaris and Scenedesmus obliquus, were used in this study. It was observed that saponin was a good frother, but not an effective collector when used alone for flotation separation of algae. However, with the pre-flocculation of 5 mg/L of chitosan, separation efficiency of >93% microalgae cells was found at 20 mg/L of saponin. Removal efficiency of >54.4% and >73.0% was found for polysaccharide and protein, respectively at 20 mg/L of saponin and chitosan each. Experimental results show that DiAF using saponin and chitosan is effective for separation of microalgae, and algogenic organic matter (AOM). It can potentially be applied in the integrated microalgae-based biorefinery. PMID:24935003

  6. Flotation of Heterocoagulated Particulates in Ulexite/SDS/Electrolyte System.

    PubMed

    Celik; Yasar; El-Shall

    1998-07-15

    Salt-type minerals can be usually floated with either anionic or cationic collectors. In a number of systems, flotation has been reported to remarkably increase above the concentrations where precipitation of the collector salt is initiated. Some studies attribute this phenomenon to heterocoagulation of oppositely charged colloidal precipitate and mineral particles. In this study, ulexite, a semisoluble boron mineral, in the presence of various multivalent ions, i.e. Ba2+, Mg2+, Ca2+, and Al3+, was found to exhibit excellent flotation even when particles, colloidal precipitates, and bubbles acquire a similar charge, which indicates that attractive structural forces exceed the forces of electrostatic repulsion. Copyright 1998 Academic Press. PMID:9705762

  7. Enhancement of randomness by flotation rest (restricted environmental stimulation technique).

    PubMed

    Sakata, S; Shinohara, J; Hori, T; Sugimoto, S

    1995-06-01

    This study was conducted to evaluate the positive effect of flotation REST on the production of random sequences, employing both behavioral and physiological measures. The subjects were 7 student volunteers who spent a 40-min. session lying alone on a bed in an isolation box and two 40-min. sessions floating in a commercially produced tank. Polygraph recordings (EEG, EOG, ECG and respiration) were made continuously. Randomness of orally generated sequences was measured by RIP scores based on the Plya-Eggenberger distribution in three test sessions, e.g., pre-, during, and post-REST period. Randomness increased in the floating condition, while those parameters decreased in the bed condition. Sleep-stage analysis and EEG spectral analysis showed that the flotation REST induced a more hypnagogic state and light sleep than did in-bed REST. It is speculated that the hypnagogic state and light sleep induced by floating enhanced random generation. PMID:7567422

  8. Benthic community composition on submerged reefs in the central Great Barrier Reef

    NASA Astrophysics Data System (ADS)

    Roberts, T. E.; Moloney, J. M.; Sweatman, H. P. A.; Bridge, T. C. L.

    2015-06-01

    Community dynamics on coral reefs are often examined only in relatively shallow waters, which are most vulnerable to many disturbances. The Great Barrier Reef World Heritage Area (GBRWHA) includes extensive submerged reefs that do not approach sea level and are within depths that support many coral reef taxa that also occur in shallow water. However, the composition of benthic communities on submerged reefs in the GBRWHA is virtually unknown. We examined spatial patterns in benthic community composition on 13 submerged reefs in the central Great Barrier Reef (GBR) at depths of 10-30 m. We show that benthic communities on submerged reefs include similar species groups to those on neighbouring emergent reefs. The spatial distribution of species groups was well explained by depth and cross-shelf gradients that are well-known determinants of community composition on emergent reefs. Many equivalent species groups occurred at greater depths on submerged reefs, likely due to variability in the hydrodynamic environment among reef morphologies. Hard coral cover and species richness were lowest at the shallowest depth (6 m) on emergent reefs and were consistently higher on submerged reefs for any given depth. These results suggest that disturbances are less frequent on submerged reefs, but evidence that a severe tropical cyclone in 2011 caused significant damage to shallow regions of more exposed submerged reefs demonstrates that they are not immune. Our results confirm that submerged reefs in the central GBR support extensive and diverse coral assemblages that deserve greater attention in ecosystem assessments and management decisions.

  9. Fish assemblages on estuarine artificial reefs: natural rocky-reef mimics or discrete assemblages?

    PubMed

    Folpp, Heath; Lowry, Michael; Gregson, Marcus; Suthers, Iain M

    2014-01-01

    If the primary goal of artificial reef construction is the creation of additional reef habitat that is comparable to adjacent natural rocky-reef, then performance should be evaluated using simultaneous comparisons with adjacent natural habitats. Using baited remote underwater video (BRUV) fish assemblages on purpose-built estuarine artificial reefs and adjacent natural rocky-reef and sand-flat were assessed 18 months post-deployment in three south-east Australian estuaries. Fish abundance, species richness and diversity were found to be greater on the artificial reefs than on either naturally occurring reef or sand-flat in all estuaries. Comparisons within each estuary identified significant differences in the species composition between the artificial and natural rocky-reefs. The artificial reef assemblage was dominated by sparid species including Acanthopagrus australis and Rhabdosargus sarba. The preference for a range of habitats by theses sparid species is evident by their detection on sand-flat, natural rocky reef and artificial reef habitats. The fish assemblage identified on the artificial reefs remained distinct from the adjacent rocky-reef, comprising a range of species drawn from naturally occurring rocky-reef and sand-flat. In addition, some mid-water schooling species including Trachurus novaezelandiae and Pseudocaranx georgianus were only identified on the artificial reef community; presumably as result of the reef's isolated location in open-water. We concluded that estuarine artificial reef assemblages are likely to differ significantly from adjacent rocky-reef, potentially as a result of physical factors such as reef isolation, coupled with species specific behavioural traits such as the ability of some species to traverse large sand flats in order to locate reef structure, and feeding preferences. Artificial reefs should not be viewed as direct surrogates for natural reef. The assemblages are likely to remain distinct from naturally occurring habitat comprised of species that reside on a range of adjacent natural habitats. PMID:23755106

  10. Fish Assemblages on Estuarine Artificial Reefs: Natural Rocky-Reef Mimics or Discrete Assemblages?

    PubMed Central

    Folpp, Heath; Lowry, Michael; Gregson, Marcus; Suthers, Iain M.

    2013-01-01

    If the primary goal of artificial reef construction is the creation of additional reef habitat that is comparable to adjacent natural rocky-reef, then performance should be evaluated using simultaneous comparisons with adjacent natural habitats. Using baited remote underwater video (BRUV) fish assemblages on purpose-built estuarine artificial reefs and adjacent natural rocky-reef and sand-flat were assessed 18 months post-deployment in three south-east Australian estuaries. Fish abundance, species richness and diversity were found to be greater on the artificial reefs than on either naturally occurring reef or sand-flat in all estuaries. Comparisons within each estuary identified significant differences in the species composition between the artificial and natural rocky-reefs. The artificial reef assemblage was dominated by sparid species including Acanthopagrus australis and Rhabdosargus sarba. The preference for a range of habitats by theses sparid species is evident by their detection on sand-flat, natural rocky reef and artificial reef habitats. The fish assemblage identified on the artificial reefs remained distinct from the adjacent rocky-reef, comprising a range of species drawn from naturally occurring rocky-reef and sand-flat. In addition, some mid-water schooling species including Trachurus novaezelandiae and Pseudocaranx georgianus were only identified on the artificial reef community; presumably as result of the reef's isolated location in open-water. We concluded that estuarine artificial reef assemblages are likely to differ significantly from adjacent rocky-reef, potentially as a result of physical factors such as reef isolation, coupled with species specific behavioural traits such as the ability of some species to traverse large sand flats in order to locate reef structure, and feeding preferences. Artificial reefs should not be viewed as direct surrogates for natural reef. The assemblages are likely to remain distinct from naturally occurring habitat comprised of species that reside on a range of adjacent natural habitats. PMID:23755106

  11. Flotation: A promising microalgae harvesting and dewatering technology for biofuels production.

    PubMed

    Ndikubwimana, Theoneste; Chang, Jingyu; Xiao, Zongyuan; Shao, Wenyao; Zeng, Xianhai; Ng, I-Son; Lu, Yinghua

    2016-03-01

    Microalgal biomass as renewable energy source is believed to be of great potential for reliable and sustainable biofuels production. However, microalgal biomass production is pinned by harvesting and dewatering stage thus hindering the developing and growing microalgae biotechnology industries. Flotation technology applied in mineral industry could be potentially applied in microalgae harvesting and dewatering, however substantial knowledge on different flotation units is essential. This paper presents an overview on different flotation units as promising cost-effective technologies for microalgae harvesting thus bestowing for further research in development and commercialization of microalgae based biofuels. Dispersed air flotation was found to be less energy consuming. Moreover, Jameson cell flotation and dispersed ozone flotation are believed to be energy efficient microalgae flotation approaches. Microalgae harvesting and dewatering by flotation is still at embryonic stage, therefore extended studies with the focus on life cycle assessment, sustainability of the flotation unit, optimization of the operating parameters using different algal species is imperative. Though there are a number of challenges in microalgae harvesting and dewatering, with well designed and developed cultivation, harvesting/dewatering, extraction and conversion technologies, progressively, microalgae technology will be of great potential for biological carbon sequestration, biofuels and biochemicals production. PMID:26928758

  12. Using alternative chemicals in the flotation of heavy metals from lead mill tailings

    SciTech Connect

    Benn, F.W.

    1995-04-01

    The U.S. Bureau of Mines (USBM) investigated alternative chemicals for the flotation of heavy metal values from southeast Missouri lead mill tailings. The objectives of the study were to lower the Pb remaining in the reprocessed tailings to <500 ppm, concentrate the metal values, and lower the overall toxicity of the flotation reagent scheme. Due to the high toxicity of classic flotation chemicals, collectorless flotation, as well as nontoxic or less-toxic chemicals, was studied for use in the flotation process. The investigation centered on the National tailings pile in Flat River, MO. Advantages to using alternative chemicals for the flotation process are presented. Novel reagent schemes are discussed for the treatment of the tailings. Various nontoxic or less-toxic oils were tested, and a substitute for sodium sulfide was investigated. Using a food additive oil, soda ash, and a frother as the reagent scheme, froth flotation recovered 89% of the Pb values. Further scavenging lowered the Pb remaining in the reprocessed tailings to <500 ppm. A less-toxic substitute for sodium cyanide was also studied for use in the cleaner flotation stages. Preliminary results indicate that the food additive oil, canola oil, to be as effective as classic sulfide flotation reagents.

  13. An investigation of pyrite depression in coal flotation by electrochemical pyrite surface control

    SciTech Connect

    Zhu Hong; Ou Zeshen; Shi Xiuping; Shen Yanchun

    1995-12-31

    This paper introduces a new potential method of pyrite depression in the flotation of high sulfur coal based on the electrochemical pyrite surface control. Experimental date show that the natural hydrophobicity of pyrite depends on the oxidation-reduction potential of the pulp. The mechanism and products of electrochemical reaction on the pyrite surface are also discussed under various conditions. The pyrite flotation is generally suppressed under low pulp potentials. Therefore, the sulfur removal in the flotation of high sulfur coal could be improved by the pulp redox potential control, while the coal flotation is materially not affected.

  14. Iron ore: energy, labor, and capital changes with technology.

    PubMed

    Kakela, P J

    1978-12-15

    Resource gathering is depending on leaner crude ores. Iron ore mining typifies this trend. To make lean taconite iron ores useful required a technologic breakthrough-pelletization. The shift to iron ore pellets has the advantage that they require less energy and labor per ton of molten iron than high-grade naturally concentrated ores. Increased reliance on pellets causes a geographic shift of some jobs and environmental effects from blast furnaces to iron ore mines. PMID:17735387

  15. Ecology of the south Florida coral reefs: a community profile

    SciTech Connect

    Jaap, W.C.

    1984-08-01

    An overview of coral reef research in southern Florida is provided as a prelude to a genuine description of the coral reef ecosystem in the Florida Keys and surrounding environments. Coral reef community types, reef benthos, plankton and reef fish are given specific treatment. Coral reef ecology and management are described. 27 figs., 31 tabs.

  16. Process of extracting both uranium and radium from uranium-containing ores

    SciTech Connect

    Nirdosh, I.; Baird, M.H.; Banerjee, S.; Muthuswami, S.V.

    1984-06-12

    Ferric chloride leaching at temperatures in the range 47-74/sup 0/C. is found to remove up to 97% of the uranium from ores occurring in the Elliot Lake area of Canada, but radium removal was found to be poor due to the formation of sulphates from the sulphides present in the ore. In processes of the invention the sulphides are initially removed by flotation, when aqueous acidic ferric chloride of relatively low concentration, e.g., 0.1 M can extract as much as 92% of the radium, giving tailings which are effectively sulphide-free and with radium levels approaching a desired maximum of 24 pCi/g. Radium may be removed by adsorption on manganese dioxide and uranium may be removed by liquid extraction with D2EHPA (DAPEX process). The ferric chloride may be recirculated for further leaching, with reduction before the uranium extraction and reoxidation afterwards. Because of the recycle, it is possible to keep chloride ion levels in the effluent below the prescribed level in Ontario, Canada of 750 ppm.

  17. Nanoparticle flotation collectors: mechanisms behind a new technology.

    PubMed

    Yang, Songtao; Pelton, Robert; Raegen, Adam; Montgomery, Miles; Dalnoki-Veress, Kari

    2011-09-01

    This is the first report describing a new technology where hydrophobic nanoparticles adsorb onto much larger, hydrophilic mineral particle surfaces to facilitate attachment to air bubbles in flotation. The adsorption of 46 nm cationic polystyrene nanoparticles onto 43 μm diameter glass beads, a mineral model, facilitates virtually complete removal of the beads by flotation. As little as 5% coverage of the bead surfaces with nanoparticles promotes high flotation efficiencies. The maximum force required to pull a glass bead from an air bubble interface into the aqueous phase was measured by micromechanics. The pull-off force was 1.9 μN for glass beads coated with nanoparticles, compared to 0.0086 μN for clean beads. The pull-off forces were modeled using Scheludko's classical expression. We propose that the bubble/bead contact area may not be dry (completely dewetted). Instead, for hydrophobic nanoparticles sitting on a hydrophilic surface, it is possible that only the nanoparticles penetrate the air/water interface to form a three-phase contact line. We present a new model for pull-off forces for such a wet contact patch between the bead and the air bubble. Contact angle measurements of both nanoparticle coated glass and smooth films from dissolved nanoparticles were performed to support the modeling. PMID:21790133

  18. Laboratory study of electro-coagulation-flotation for water treatment.

    PubMed

    Jiang, Jia-Qian; Graham, Nigel; André, Cecile; Kelsall, Geoff H; Brandon, Nigel

    2002-09-01

    An electro-coagulation-flotation process has been developed for water treatment. This involved an electrolytic reactor with aluminium electrodes and a separation/flotation tank. The water to be treated passed through the reactor and was subjected to coagulation/flotation, by Al(III) ions dissolved from the electrodes, the resulting flocs floating after being captured by hydrogen gas bubbles generated at cathode surfaces. Apparent current efficiencies for Al dissolution as aqueous Al(III) species at pH 6.5 and 7.8 were greater than unity. This was due to additional reactions occurring in parallel with Al dissolution: oxygen reduction at anodes and cathodes, and hydrogen evolution at cathodes, resulting in net (i.e. oxidation + reduction) currents at both anodes and cathodes. The specific electrical energy consumption of the reactor for drinking water treatment was as low as 20 kWh (kg Al)(-1) for current densities of 10-20A m(-2). The water treatment performance of the electrocoagulation process was found to be superior to that of conventional coagulation with aluminium sulphate for treating a model-coloured water, with 20% more dissolved organic carbon (DOC) being removed for the same Al(III) dose. However, for a lowland surface water sample, the two processes achieved a similar performance for DOC and UV-absorbance removal. In addition, an up-flow electrocoagulator configuration performed better than a horizontal flow configuration, with both bipolar and monopolar electrodes. PMID:12405415

  19. AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION

    SciTech Connect

    1998-10-25

    A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the tenth quarter of this project, Task 6 (Equipment Procurement and Installation) was completed through the efforts of J.A. Herbst and Associates, Virginia Tech, Pittston Coal Company, and FGR Automation. As a result of this work, a model-based control system is now in place which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. Testing of this control system is expected to be carried out during the next quarter, and the results of this testing will be reported in the Eleventh Quarterly report. In addition, calibration of the video-based ash analyzer was continued and an extensive set of calibration data were obtained showing that the plant is running remarkably well under manual control. This may be a result of increased attention being paid to froth flotation as a result of this project.

  20. AN ADVANCED CONTROL SYSTEM FOR FINE COAL FLOTATION

    SciTech Connect

    G.H. Luttrell; G.T. Adel

    1999-01-11

    A model-based flotation control scheme is being implemented to achieve optimal performance in the handling and treatment of fine coal. The control scheme monitors flotation performance through on-line analysis of tailings ash content. Then, based on an on-line estimate of incremental ash, the pulp level is adjusted using a model-based control algorithm to compensate for feed variations and other process disturbances. Recent developments in sensor technology are being applied for on-line determination of slurry ash content. During the eleventh quarter of this project, Task 7 (Operation and Testing) was nearly completed through the efforts of J.A. Herbst and Associates, Virginia Tech, and Pittston Coal Company. As a result of this work, a model-based control system has now been installed which can predict incremental ash based on tailings ash content and general plant data, and adjust pulp level accordingly to maintain a target incremental ash. The system has gone through a shake-down period, training has been carried out for plant operators, and the bulk of the control logic testing has been completed with the results of these tests awaiting analysis under Task 8 (System Evaluation). The flotation model has been shown to predict incremental ash quite successfully, implying that this approach may provide the basis for a useful ''soft sensor'' for on-line incremental ash analysis.

  1. Flotation and flocculation chemistry of coal and oxidized coals

    SciTech Connect

    Somasundaran, P.

    1990-01-01

    The objective of this research project is to understand the fundamentals involved in the flotation and flocculation of coal and oxidized coals and elucidate mechanisms by which surface interactions between coal and various reagents enhance coal beneficiation. An understanding of the nature of the heterogeneity of coal surfaces arising from the intrinsic distribution of chemical moieties is fundamental to the elucidation of mechanism of coal surface modification and its role in interfacial processes such as flotation, flocculation and agglomeration. A new approach for determining the distribution in surface properties of coal particles was developed in this study and various techniques capable of providing such information were identified. Distributions in surface energy, contact angle and wettability were obtained using novel techniques such as centrifugal immersion and film flotation. Changes in these distributions upon oxidation and surface modifications were monitored and discussed. An approach to the modelling of coal surface site distributions based on thermodynamic information obtained from gas adsorption and immersion calorimetry is proposed. Polyacrylamide and dodecane was used to alter the coal surface. Methanol adsorption was also studied. 62 figs.

  2. Microcel{trademark} flotation technology in the international marketplace

    SciTech Connect

    Yoon, R.H.; Luttrell, G.H.; Phillips, D.I.

    1996-12-31

    The Microcel flotation column was developed under the auspices of the US Department of Energy and is based on the concept that the rate of flotation increase with decreasing bubble size. In this technology, small air bubbles are generated by agitating part of the slurry at the bottom of a flotation column by means of in-line mixers and a centrifugal pump. The size of bubbles generated in full-size columns are usually controlled in the range of 0.25 to 1.0 mm depending on the particle size and hydrophobicity of the particles to be floated. As a result of using small air bubbles (which are sometimes referred to as microbubbles), the Microcel columns can recovery very fine coal particles with high recoveries. The fine coal particles collected by the microbubbles are washed in the froth phase using fresh water to obtain high-grade products. Thus, Microcel columns are capable of producing high-grade products with high recoveries. Other advantages of the Microcel columns include throughput, low maintenance requirement, and low energy consumption. Because of these advantages, the Microcel columns have been installed in the US, Australia and China for coal cleaning and in Spain and Chile for processing sulfide minerals. In this presentation, some of the scale-up test work will be presented and the economic benefits of installing Microcels will be discussed.

  3. Coal surface control for advanced fine coal flotation

    SciTech Connect

    Fuerstenau, D.W.; Sastry, K.V.S.; Hanson, J.S.; Diao, J.; De, A.; Sotillo, F.; Harris, G. ); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. ); Hu, Weibai; Zou, Y.; Chen, W. ); Choudhry, V.; Sehgal, R.; Ghosh, A. (Praxis Engineers, Inc., Milpitas, CA (United

    1991-07-30

    The primary objective in the scope of this research project is to develop advanced flotation methods for coal cleaning in order to achieve near total pyritic-sulfur removal at 90% Btu recovery, using coal samples procured from three major US coal seams. Concomitantly, the ash content of these coals is to be reduced to 6% or less. Investigation of mechanisms for the control of coal and pyrite surfaces prior to fine coal flotation is the main aspect of the project objectives. The results of this research are to be made available to ICF Kaiser Engineers who are currently working on the Engineering Development of Advanced Flotation under a separate contract with DOE under the Acid Rain Control Initiative program. A second major objective is to investigate factors involved in the progressive weathering and oxidation of coal that had been exposed to varying degrees of weathering, namely, open to the atmosphere, covered and in an argon-inerted'' atmosphere, over a period of twelve months. After regular intervals of weathering, samples of the three base coals (Illinois No. 6, Pittsburgh No. 8 and Upper Freeport PA) were collected and shipped to both the University of Pittsburgh and the University of California at Berkeley for characterization studies of the weathered material. 29 figs., 29 tabs.

  4. Miocene precursors to Great Barrier Reef

    SciTech Connect

    Davies, P.J.; Symonds, P.A.; Feary, D.A.; Pigram, C.

    1988-01-01

    Huge reefs of Miocene age are present in the Gulf of Papua north of the present-day Great Barrier Reef and to the east on the Marion and Queensland Plateaus. In the Gulf of Papua, Miocene barrier reefs formed the northern forerunner of the Great Barrier Reef, extending for many hundreds of kilometers along the eastern and northern margin of the Australian craton within a developing foreland basin. Barrier reefs, slope pinnacle reefs, and platform reefs are seen in seismic sections and drill holes. Leeside talus deposits testify to the high energy impinging on the eastern margin of these Miocene reefs. The Queensland Plateau is a marginal plateau east of the central Great Barrier Reef and separated from it by a rift trough. Miocene reefs occupied an area of about 50,000 km/sup 2/ and grew on salt-controlled highs on the western margin of the plateau and on a regional basement high extending from the platform interior to its southern margin. Reef growth has continued to the present day, although two major contractions in the area covered by reefs occurred during the Miocene. The Marion Plateau is present directly east of the Great Barrier Reef and during the Micoene formed a 30,000-km/sup 2/ platform with barrier reefs along its northern margin and huge platform reefs and laggons on the platform interior. These reefs grew on a flat peneplained surface, the whole area forming a large shallow epicontinental sea. In all three areas, the middle Miocene formed the acme of reef expansion in the region.

  5. Ancient reef ecosystem expansion and collapse

    NASA Astrophysics Data System (ADS)

    Copper, P.

    1994-01-01

    Platform carbonate and, particularly, reef ecosystem development (with reefs representing the acme of carbonate platform growth) were highly cyclical in early to mid Paleozoic time, especially in relation to known or postulated times of global warming or cooling. These cycles do not appear to correspond to postulated 26 Ma rhythms seen in diversity patterns, nor were they regular. There were major periods of worldwide reef expansion (e.g. mid-Silurian-Late Devonian), corresponding to global warming well above present day norms, and periods of complete global reef collapse (e.g., mid-Cambrian to mid-Ordovician, Late Devonian) corresponding to global perturbations. At times of major reef expansion in the Paleozoic, areas covered by equatorial reef and inter-reef carbonate platforms are conservatively estimated to have periodically exceeded 5 million sq. km, nearly ten times that in the modern ocean. At times of global reef collapse, e.g. the Famennian (Late Devonian), reef complexes were completely absent or, at best, covered <1000 sq. km. The chief factors relating to periodic collapse and mass extinction of reef biotas appear to be related to climatic change and possibly ocean anoxic events, in turn as a response to large scale, geologically disruptive factors such as plate collisions, plate movement across equatorial belts and volcanism. Stress signals in Cambrian through Cretaceous reef ecosystems appear to be comparable to those of today: whether these relate to physical versus biological stress is uncertain. Reef stress is evident in globally reduced areas and thicknesses of reef carbonate production, the absence of large scale barrier reef systems and reduction to smaller patch reef complexes (or, periodically, following mass extinctions, no reefs at all), reduced species and genus diversity, small skeletons or colonies, limited or no biotic zonation along reef transects, and arrested succession and ecologic replacement of complex, more highly evolved taxa by simpler, stress-resistant disaster taxa at the genus to ordinal (or even phylum) level.

  6. Direct Reduction of Iron Ore

    NASA Astrophysics Data System (ADS)

    Small, M.

    1981-04-01

    In the search for a pure, available iron source, steelmakers are focusing their attention on Directly Reduced Iron (DRI). This material is produced by the reaction of a low gangue iron ore with a hydrocarbonaceous substance. Commercially, DRI is generated in four different reactors: shaft (moving-bed), rotary kiln, fluidized bed, and retort (fixed-bed). Annual worldwide production capacity approaches 33 million metric tons. Detailed assessments have been made of the uses of DRI, especially as a substitute for scrap in electric furnace (EF) steelmaking. DRI is generally of a quality superior to current grades of scrap, with steels produced more efficiently in the EF and containing lower levels of impurities. However, present economics favor EF steel production with scrap. But this situation could change within this decade because of a developing scarcity of good quality scrap.

  7. Selective flotation of fossil resin from Western coal. Final report, July 1, 1990--May 25, 1992

    SciTech Connect

    Jensen, G.F.; Miller, J.D.

    1992-05-25

    The proof-of-concept test program was designed to clarify a number of concerns that have been raised by coal companies who own the valuable resin resource. First, from laboratory bench-scale flotation experiments, a froth product from cleaner flotation containing more than 80% hexane-extractable resin at higher than 80% recovery can be produced. Pilot-plant testing was initiated to demonstrate the selective flotation of fossil resin and to establish a better confidence level in the new technology. Second, pilot-plant testing was designed to evaluate the effect and impact of random variation in slurry solids concentration and feed grade on this new selective fossil resin flotation technology. The flotation performance obtained under these industrial conditions is more realistic for process evaluation. Third, more accurate operating cost data was to be obtained for economic analysis. Fourth, sufficient quantities of the fossil resin concentrate were to be produced from the test program for evaluation by potential industrial users. Fifth, and finally, optimum levels for the operating variables were to be established. Such information was required for eventual scale-up and design of a fossil resin flotation plant. The pilot-plant proof-of-concept testing of selective resinate flotation has demonstrated that: (1) technically, the new flotation technologies discovered at the University of Utah and then improved upon by Advanced Processing Technologies, Inc. provide a highly efficient means to selectively recover fossil resin from coal. The proof-of-concept continuous flotation circuit (about 0.1 tph) resulted in fossil resin recovery with the same separation efficiency as was obtained from laboratory bench-scale testing (more than 80% recovery at about 80% concentrate grade); and (2) economically, the selective flotation process has been shown to be sufficiently profitable to justify the development of a fossil resin industry based on this new flotation process.

  8. Coral reefs: building a better crystal ball.

    PubMed

    Bruno, John F

    2013-06-01

    Reef corals are ancient taxa, yet they are highly sensitive to environmental change. Recent research indicates that unless global CO2 emissions are dramatically reduced, we are just decades away from the collapse of coral reef ecosystems. PMID:23743410

  9. Reef Squid at USGS Monitoring Station

    USGS Multimedia Gallery

    A curious reef squid hovers over a calcification-monitoring station used to measure calcification rates to determine impact of ocean acidification on coral growth at Fowey Rocks Light Reef in Biscayne National Park.  ...

  10. Ocean acidification worse in coral reefs

    NASA Astrophysics Data System (ADS)

    Betz, Eric O.

    2014-12-01

    The rate of ocean acidification in coral reefs outpaces the rise in carbon dioxide (CO2) in Earth's atmosphere, indicating that anthropogenic carbon emissions alone are not to blame for the threat to coral reefs, a new study shows.

  11. Mineral and Elemental Composition Features of "Loose" Oolitic Ores in Bakchar Iron Ore Cluster (Tomsk Oblast)

    NASA Astrophysics Data System (ADS)

    Rudmin, M.; Mazurov, A.; Bolsunovskaya, L.

    2014-08-01

    Geo-technological investigation considerations of iron ore deposits within the Bakchar ore cluster are being carried out. The mineral and elemental composition of "loose" ores have been studied, embracing such important aspects as the distribution pattern of valuable and harmful impurities, the determination of element concentrators (such as vanadium, phosphate and sulphur) in basic minerals and the analysis of ore composition varaiation in volume ore cluster. Based on investigation results the mineral and elemental composition characteristic features of "loose" ores were defined. Although hydrogoethite was the basic identified ore mineral, such minerals as goethite, lepidocrocite, leptochlorite, siderite and hisingerite were also found. The deportment of calcium phosphate (anapaite) and phosphates of rare-earth elements (monazite, killarite), which are associated with the harmful impurity- phosphorous, are described. It has been defined that the ore constituent composition contains such persistent impurities as vanadium and manganese, the content of which is 0.35% and 0.03%, respectively. The "loose" ores are continuous in mineral composition, both in area and cross-section throughout the Bakchar ore cluster. Based on the sample element composition analysis the most perspective areas for further mineral processing could be: western with the fraction of 1....0.2mm. and eastern- fraction of 1...0.1mm.

  12. The Geohydrology of MVT-Ore Genesis in the Canning Basin, Western Australia

    NASA Astrophysics Data System (ADS)

    Garven, G.; Wallace, M. M.

    2009-05-01

    In the Lennard Shelf, Western Australia, epigenetic MVT-type Pb-Zn mineralization occurs in Middle Devonian evaporitic dolomites which were part of a barrier reef system (Hurley & Lohmann, 1989). Ore mineralization exhibits a strong structural control at the basin scale and normal faults probably controlled pathways for brine and petroleum migration that affected ore deposition (Wallace et al., 1999). For the Canning basin, finite element simulations show that compaction was the most important process for creating overpressures and driving basinal fluids in this thick extensional basin. Basinal fluids are shown to have been driven across the Fitzroy Trough through permeable and deeply buried Silurian-Ordovician aquifer units. The fluids then migrated upwards at rates of m/yr up during periods of episodic extension (Braun, 1992) where fluid flow was channeled by major normal fault zones like the Cadjebut and Pinnacles Faults. Reactive flow simulations test a petroleum-reservoir model for mineralization whereby metal-bearing brines mix with accumulated hydrocarbons (Anderson & Garven, 1987). The results show that compaction-driven flow, as proposed by Beales & Jackson (1966) and Jackson & Beales (1967), works rather well in this ore district--other mechanisms such as sealevel tidal pumping (Cathles, 1988) or topographic drive (Solomon & Groves, 1994) are more tenuous and really unnecessary from a mass transport or geohydrologic basis.

  13. REEF: Retainable Evaluator Execution Framework

    PubMed Central

    Weimer, Markus; Chen, Yingda; Chun, Byung-Gon; Condie, Tyson; Curino, Carlo; Douglas, Chris; Lee, Yunseong; Majestro, Tony; Malkhi, Dahlia; Matusevych, Sergiy; Myers, Brandon; Narayanamurthy, Shravan; Ramakrishnan, Raghu; Rao, Sriram; Sears, Russell; Sezgin, Beysim; Wang, Julia

    2015-01-01

    Resource Managers like Apache YARN have emerged as a critical layer in the cloud computing system stack, but the developer abstractions for leasing cluster resources and instantiating application logic are very low-level. This flexibility comes at a high cost in terms of developer effort, as each application must repeatedly tackle the same challenges (e.g., fault-tolerance, task scheduling and coordination) and re-implement common mechanisms (e.g., caching, bulk-data transfers). This paper presents REEF, a development framework that provides a control-plane for scheduling and coordinating task-level (data-plane) work on cluster resources obtained from a Resource Manager. REEF provides mechanisms that facilitate resource re-use for data caching, and state management abstractions that greatly ease the development of elastic data processing work-flows on cloud platforms that support a Resource Manager service. REEF is being used to develop several commercial offerings such as the Azure Stream Analytics service. Furthermore, we demonstrate REEF development of a distributed shell application, a machine learning algorithm, and a port of the CORFU [4] system. REEF is also currently an Apache Incubator project that has attracted contributors from several instititutions.1 PMID:26819493

  14. Miocene reefs of Dominican Republic

    SciTech Connect

    Evans, C.C.

    1988-01-01

    The reefs are overlain by conglomeratic strata. The stratigraphic setting of these reefs suggests that they have developed along the stalled portions of rapidly prograding fan deltas. Thickets and layers of coral debris are found seaward and stratigraphically above the well-developed reef. The matrix sediments are exclusively fine-grained sand to mud, and the fauna are suggestive of more open shelf conditions. In thickets, branched (porites spp., Pocillopora spp.), small massive (Montastrea spp., Siderastrea spp.), and foliose or plate like (Agaricia spp.) corals are found upright in the muddy sediment. Similarities in coral species and areal proximity suggest that thickets are the source of most layers of coralline debris. The association of coral debris with graded bedding and cross-bedding suggests that coral debris has been reworked by storms. The growth of corals and development of coral reefs in the Miocene-Pliocene Yaque Group is limited only by opportunities created by the slowing of siliciclastic sedimentation. Soft, muddy, terrigenous substrates and a continuing supply of terrigenous mud exert only a limited, indirect effect on reef growth.

  15. Reduction Mechanisms in Manganese Ore Reduction

    NASA Astrophysics Data System (ADS)

    Coetsee, Theresa; Reinke, Christian; Nell, Johannes; Pistorius, Petrus Christiaan

    2015-12-01

    Manganese ores are highly heterogeneous and contain various minerals with different levels of contained manganese and iron and therefore the ore reduction behavior is not uniform. Both phase chemistry and phase morphology at the reaction interface, at micron scale, must be investigated to understand the reaction mechanism effects in manganese ore reduction. This approach is applied here to reacted material mixture samples taken from the AlloyStream pilot plant furnace over a period of 4 months. The mineralogical features are reported and discussed. Deductions are made on the likely dominant reduction mechanism in this reaction system, given the phase morphology observations presented.

  16. 46 CFR 117.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 4 2012-10-01 2012-10-01 false Personal flotation devices carried in addition to life... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 117.72 Personal flotation devices carried in addition to life jackets. (a) Equipment carried under this section is not acceptable...

  17. 46 CFR 117.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 4 2010-10-01 2010-10-01 false Personal flotation devices carried in addition to life... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 117.72 Personal flotation devices carried in addition to life jackets. (a) Equipment carried under this section is not acceptable...

  18. 46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Personal flotation devices carried in addition to life... PASSENGER VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 180.72 Personal flotation devices carried in addition to life jackets. (a) Equipment...

  19. 46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Personal flotation devices carried in addition to life... PASSENGER VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 180.72 Personal flotation devices carried in addition to life jackets. (a) Equipment...

  20. 46 CFR 117.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 4 2014-10-01 2014-10-01 false Personal flotation devices carried in addition to life... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 117.72 Personal flotation devices carried in addition to life jackets. (a) Equipment carried under this section is not acceptable...

  1. 46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Personal flotation devices carried in addition to life... PASSENGER VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 180.72 Personal flotation devices carried in addition to life jackets. (a) Equipment...

  2. 46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Personal flotation devices carried in addition to life... PASSENGER VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 180.72 Personal flotation devices carried in addition to life jackets. (a) Equipment...

  3. 46 CFR 180.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Personal flotation devices carried in addition to life... PASSENGER VESSELS (UNDER 100 GROSS TONS) LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 180.72 Personal flotation devices carried in addition to life jackets. (a) Equipment...

  4. 46 CFR 117.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 4 2013-10-01 2013-10-01 false Personal flotation devices carried in addition to life... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 117.72 Personal flotation devices carried in addition to life jackets. (a) Equipment carried under this section is not acceptable...

  5. 46 CFR 117.72 - Personal flotation devices carried in addition to life jackets.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 4 2011-10-01 2011-10-01 false Personal flotation devices carried in addition to life... PASSENGERS LIFESAVING EQUIPMENT AND ARRANGEMENTS Ring Life Buoys and Life Jackets 117.72 Personal flotation devices carried in addition to life jackets. (a) Equipment carried under this section is not acceptable...

  6. 46 CFR 25.25-15 - Retroreflective material for personal flotation devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 1 2014-10-01 2014-10-01 false Retroreflective material for personal flotation devices. 25.25-15 Section 25.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS Life Preservers and Other Lifesaving Equipment 25.25-15 Retroreflective material for personal flotation devices. (a) Each...

  7. 46 CFR 169.741 - Personal flotation devices and ring life buoys.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 7 2011-10-01 2011-10-01 false Personal flotation devices and ring life buoys. 169.741 Section 169.741 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings 169.741 Personal flotation devices and ring life buoys....

  8. 46 CFR 25.25-15 - Retroreflective material for personal flotation devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 1 2012-10-01 2012-10-01 false Retroreflective material for personal flotation devices. 25.25-15 Section 25.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS Life Preservers and Other Lifesaving Equipment 25.25-15 Retroreflective material for personal flotation devices. (a) Each...

  9. 33 CFR 183.235 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Level flotation test without weights for persons capacity. 183.235 Section 183.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines...

  10. Study on the application of FCMC-1500 cyclonic microbubble flotation column for coal preparation

    SciTech Connect

    Xie Guangyuan; Ou Zeshen; Ge Mi; Wang Yongtian; Liu Jiongtian

    1997-12-31

    In this paper the cyclonic microbubble flotation column is introduced. Its structure and the principle of operation along with some results in a commercial plant are also presented. The test results have demonstrated the cyclonic microbubble flotation column to be highly selective and extremely efficient in ash rejection from fine coals, oil consumption, and energy conservation. It has a great future for commercialization.

  11. IMPROVED FLOTATION TECHNIQUE FOR MICROSCOPY OF 'IN SITU' SOIL AND SEDIMENT MICROORGANISMS

    EPA Science Inventory

    An improved flotation method for microscopical examination of in situ soil and sediment microorganisms was developed. Microbial cells were released into gel-like flotation films that were stripped from soil and sediment aggregates as these aggregates were submerged in 0.5% soluti...

  12. 33 CFR 183.335 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Level flotation test without weights for persons capacity. 183.335 Section 183.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of...

  13. 46 CFR 169.741 - Personal flotation devices and ring life buoys.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 7 2013-10-01 2013-10-01 false Personal flotation devices and ring life buoys. 169.741 Section 169.741 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings 169.741 Personal flotation devices and ring life buoys....

  14. 33 CFR 183.235 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Level flotation test without weights for persons capacity. 183.235 Section 183.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines...

  15. 46 CFR 169.741 - Personal flotation devices and ring life buoys.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 7 2010-10-01 2010-10-01 false Personal flotation devices and ring life buoys. 169.741 Section 169.741 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings 169.741 Personal flotation devices and ring life buoys....

  16. 46 CFR 25.25-15 - Retroreflective material for personal flotation devices.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 46 Shipping 1 2011-10-01 2011-10-01 false Retroreflective material for personal flotation devices. 25.25-15 Section 25.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS Life Preservers and Other Lifesaving Equipment 25.25-15 Retroreflective material for personal flotation devices. (a) Each...

  17. 33 CFR 183.335 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 33 Navigation and Navigable Waters 2 2013-07-01 2013-07-01 false Level flotation test without weights for persons capacity. 183.335 Section 183.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of...

  18. 33 CFR 183.335 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 33 Navigation and Navigable Waters 2 2014-07-01 2014-07-01 false Level flotation test without weights for persons capacity. 183.335 Section 183.335 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines of...

  19. 46 CFR 25.25-15 - Retroreflective material for personal flotation devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 46 Shipping 1 2013-10-01 2013-10-01 false Retroreflective material for personal flotation devices. 25.25-15 Section 25.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS Life Preservers and Other Lifesaving Equipment 25.25-15 Retroreflective material for personal flotation devices. (a) Each...

  20. 33 CFR 183.235 - Level flotation test without weights for persons capacity.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 33 Navigation and Navigable Waters 2 2012-07-01 2012-07-01 false Level flotation test without weights for persons capacity. 183.235 Section 183.235 Navigation and Navigable Waters COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) BOATING SAFETY BOATS AND ASSOCIATED EQUIPMENT Flotation Requirements for Outboard Boats Rated for Engines...

  1. 46 CFR 169.741 - Personal flotation devices and ring life buoys.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 46 Shipping 7 2012-10-01 2012-10-01 false Personal flotation devices and ring life buoys. 169.741 Section 169.741 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING SCHOOL VESSELS Vessel Control, Miscellaneous Systems, and Equipment Markings 169.741 Personal flotation devices and ring life buoys....

  2. 46 CFR 25.25-15 - Retroreflective material for personal flotation devices.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 46 Shipping 1 2010-10-01 2010-10-01 false Retroreflective material for personal flotation devices. 25.25-15 Section 25.25-15 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY UNINSPECTED VESSELS REQUIREMENTS Life Preservers and Other Lifesaving Equipment 25.25-15 Retroreflective material for personal flotation devices. (a) Each...

  3. 46 CFR 169.741 - Personal flotation devices and ring life buoys.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 46 Shipping 7 2014-10-01 2014-10-01 false Personal flotation devices and ring life buoys. 169.741 Section 169.741 Shipping COAST GUARD, DEPARTMENT OF HOMELAND SECURITY (CONTINUED) NAUTICAL SCHOOLS SAILING... devices and ring life buoys. Each personal flotation device and ring life buoy must be marked with...

  4. 18 CFR 1304.400 - Flotation devices and material, all floating structures.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating... manufactured flotation device or material specifically designed for marine applications (for example,...

  5. 18 CFR 1304.400 - Flotation devices and material, all floating structures.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating... manufactured flotation device or material specifically designed for marine applications (for example,...

  6. 18 CFR 1304.400 - Flotation devices and material, all floating structures.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating... manufactured flotation device or material specifically designed for marine applications (for example,...

  7. 18 CFR 1304.400 - Flotation devices and material, all floating structures.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... material, all floating structures. 1304.400 Section 1304.400 Conservation of Power and Water Resources... STRUCTURES AND OTHER ALTERATIONS Miscellaneous § 1304.400 Flotation devices and material, all floating... manufactured flotation device or material specifically designed for marine applications (for example,...

  8. 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

  9. 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

  10. Removal of trace levels of phenols from aqueous solution by foam flotation

    SciTech Connect

    Nyssen, G.A.; Lovell, G.S.; Simon, A.A.; Smith, J.G.; Tolar, B.K.; Wilson, D.J.

    1987-11-01

    Pentachlorophenol (PCP) was removed from water by foam flotation with the cationic surfactant cetyltrimethylammonium bromide (CTAB). With initial PCP concentrations of 20 ppm or less, residual PCP concentrations of less than 0.05 ppm were obtained after 5 min flotation. The CTAB concentration and flotation time are directly related to the amount of PCP removed. PCP removal is most efficient at neutral to basic pH and at low ionic strength. PCP removal is less effective with sodium dodecyl sulfate. As much as 80% of the CTAB can be replaced by dodecylamine without inhibiting PCP removal. Alcohols up to 10% by volume do not affect PCP removal. Other phenols can be removed equally well be foam flotation if the phenol is in the anionic form during flotation.

  11. Effective harvesting of low surface-hydrophobicity microalgae by froth flotation.

    PubMed

    Garg, Sourabh; Wang, Liguang; Schenk, Peer M

    2014-05-01

    Microalgae harvesting by air flotation is a promising technology for large-scale production of biofuel, feed and nutraceuticals from algae. With an adherence-to-hydrocarbon method and two different types of flotation cells (mechanically agitated cell and Jameson cell), microalgal surface hydrophobicity and bubble size were identified to be critical for effective froth flotation of microalgae. Freshwater alga Chlorella sp. BR2 showed naturally a high hydrophobicity and an ideal response to flotation. However, many marine microalgae possess a low surface hydrophobicity and are thus difficult to harvest. This paper shows that a step-wise optimization approach can substantially improve the flotation of a low surface hydrophobicity marine microalga, Tetraselmis sp. M8, to near full recovery with an enrichment ratio of 11.4. PMID:24690467

  12. Response of an industrial coal flotation circuit to changing reagent dosages

    SciTech Connect

    Suardini, P.J.; Kawatra, S.K.

    1995-10-01

    A number of on-stream coal slurry analyzers are presently being developed and commercialized for measuring ash and solids in coal process streams, particularly around flotation circuits. The eventual goal of these efforts is to develop on-line quality control systems for flotation circuits and other fine-coal cleaning operations. As part of this on-line monitoring and control effort, it is important to gain a better understanding of the response of industrial flotation circuits to changing operating conditions. This paper summarizes the results from a detailed sampling program performed at an industrial coal flotation circuit in western Pennsylvania. The testing focused on evaluating the response of the circuit to changes in reagent dosages, operating conditions sand feed compositions. The testing indicated that it is desirable to maintain high collector-to-frother ratios to enhance coarse particle flotation. The recovery of fine impurity particles was also proportional to water recovery, due to hydraulic entrainment.

  13. Effect of ultrasound on flotation kinetics in the reactor-separator

    NASA Astrophysics Data System (ADS)

    Filippov, L. O.; Matinin, A. S.; Samiguin, V. D.; Filippova, I. V.

    2013-03-01

    Effect of the ultrasound on flotation kinetics in reactor-separator has been studied for chalcopyrite/quartz mix mineral system. Under ultrasound treatment, recovery of chalcopyrite into bulk concentrate is higher than that at reagent-only treatment. It can be explained by increased of flotation rate for slow fraction as defined by Kelsall model. The slow fraction flotation rate increase multiplied by 6 vs. ultrasound treatment. Additional effect of the ultrasound treatment has been noticed under conditions when gangue minerals detachment from bubbles can be controlled. Reactor-separator has advantages over other types of flotation cells for this purpose providing a special zone for the ultrasound treatment that can be easily designed in this impeller less machine. The ultrasound influence on particles collision probability is able to explain of chalcopyrite recovery increase in the concentrate and activation chalcopyrite particles flotation.

  14. Coral reef crisis in deep and shallow reefs: 30 years of constancy and change in reefs of Curacao and Bonaire

    NASA Astrophysics Data System (ADS)

    Bak, Rolf P. M.; Nieuwland, Gerard; Meesters, Erik H.

    2005-11-01

    Coral reefs are thought to be in worldwide decline but available data are practically limited to reefs shallower than 25 m. Zooxanthellate coral communities in deep reefs (30-40 m) are relatively unstudied. Our question is: what is happening in deep reefs in terms of coral cover and coral mortality? We compare changes in species composition, coral mortality, and coral cover at Caribbean (Curacao and Bonaire) deep (30-40 m) and shallow reefs (10-20 m) using long-term (1973-2002) data from permanent photo quadrats. About 20 zooxanthellate coral species are common in the deep-reef communities, dominated by Agaricia sp., with coral cover up to 60%. In contrast with shallow reefs, there is no decrease in coral cover or number of coral colonies in deep reefs over the last 30 years. In deep reefs, non-agaricid species are decreasing but agaricid domination will be interrupted by natural catastrophic mortality such as deep coral bleaching and storms. Temperature is a vastly fluctuating variable in the deep-reef environment with extremely low temperatures possibly related to deep-reef bleaching.

  15. The sources of our iron ores. II

    USGS Publications Warehouse

    Burchard, E.F.

    1933-01-01

    In this instalment** the iron ore deposits of the Lake Superior States, which normally furnish about 80 per cent, of the annual output of the United States, are described together with historical notes on discovery and transportation of ore. Deposits in the Mississippi Valley and Western States are likewise outlined and the sources of imported ore are given. Reviewing the whole field, it is indicated that the great producing deposits of the Lake Superior and southern Appalachian regions are of hematite in basin areas of sedimentary rocks, that hydrated iron oxides and iron carbonates are generally found in undisturbed comparatively recent sediments, and that magnetite occurs in metamorphic and igneous rocks; also that numerical abundance of deposits is not a criterion as to their real importance as a source of supply. Statistics of production of iron ore and estimates of reserves of present grade conclude the paper.

  16. Distribution of ore deposits and spectrographic analyses of some rocks and ores on the Colorado Plateau

    USGS Publications Warehouse

    Riley, Leonard Benjamin; Shoemaker, Eugene Merle

    1952-01-01

    The geographic pattern of known igneous rocks and ore deposits on the Colorado Plateau suggests a zonal arrangement of several types of ore deposits around centers of igneous activity. Spectrographic analyses of rocks and ores on the Plateau have been obtained in an effort to determine the distribution of elements and to examine the relationships between types of ore deposits and between the ore deposits and igneous rocks. Over 170 analyses of rocks and ores are given in this report. A preliminary study of these analyses suggests that the proportion of uranium, vanadium, copper, and silver in the uranium ores varies geographically, and that the pattern of variation may be in part concentric about some of the major laccolithic intrusions. It is also suggested that the following ratios of metals contained in the uranium ores are possible guides to larger-than-average ore deposits: (1) lead/uranium greater than 1, (2) lead/zinc greater than 10, and (3) zinc/geometric mean of cobalt and nickel less than 10.

  17. Mercury Isotope Variations in Hydrothermal Ore Deposits

    NASA Astrophysics Data System (ADS)

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

    2004-12-01

    The ability to make direct isotopic measurements of ore-forming metals using MC-ICPMS has introduced the possibility for their use as tracers of Hg source in ore deposits and the environment. The isotopic composition of Hg varies by over 5 \\permil \\delta202Hg/198Hg (relative to our Almaden Hg standard), more than 50 times the 0.1 \\permil (2\\sigma ) analytical uncertainty, in a wide variety of hydrothermal ore deposits. This variation could be caused by fractionation related to processes of redox, mineral precipitation, and boiling hydrothermal fluids, among others, that are known to cause large isotopic variations in other stable isotope systems. To test the possibility that Hg isotopes can be used as a tracer of source, we have compared isotopic compositions of ore and possible source rocks in three ore deposit types: epithermal Au-Ag veins and sinter where fluids boiled in the shallow crust; silica-carbonate-type Hg deposits in the California Coast Range, where reduced source fluids mixed with oxygenated groundwater and MVT Pb-Zn deposits, where sulfides are deposited in a basin without redox or boiling. Epithermal ores (-3.1 to +2.5 \\permil) and silica-carbonate-type ores (-1.1 to +1.3 \\permil) have Hg isotopic compositions that show much larger variations than MVT ores (-0.5 to +0.6 \\permil ). The large variations might reflect the effects of fractionation by boiling and oxidation in epithermal and silica-carbonate-type deposits. At the Buckskin National epithermal deposit, unaltered andesite, felsic dike and phyllite basement rock have identical isotopic compositions of -1.3 \\permil in the middle of the epithermal ore range, as might be expected if the light and heavy ends of the range were produced by fractionation related to boiling. At the Mayacmas silica-carbonate Hg district, rocks from the Franciscan Complex and Coast Range Ophiolite range from -2.4 to 0.0 \\permil compared to a range of -0.2 to +1.3 \\permil for ores, as might be expected if kinetic isotope effects related to oxidation concentrated heavy isotopes in the ore. In laboratory experiments, a 1.3 \\permil fractionation between vapor and liquid Hg at 20 \\deg C, and a 0.1 \\permil fractionation between dissolved Hg and HgS in precipitation experiments were measured and further experiments are being conducted to better understand the processes fractionating Hg. The above results suggest that Hg isotopic variability is widespread in hydrothermal systems and may be sufficient to trace Hg source given an understanding of the fractionation mechanisms operating in these systems.

  18. Characterisation and Processing of Some Iron Ores of India

    NASA Astrophysics Data System (ADS)

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

    2013-10-01

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

  19. An evaluation of fine coal flotation at the Chaili Coal Washery

    SciTech Connect

    Zhang, R.Z.; Jiang, S.X.; Yu, Z.D.; Phillips, D.I.; Gebhardt, J.E.

    1995-12-31

    The potential application of flotation for the treatment and processing of a fine-particle coal stream was investigated for the Chaili Coal Washery of the Zaozhuang Coal Mine Administration, Shandong Province, China. A goal of the test work was to evaluate the application of the Microcel{trademark} flotation column and compare its performance to conventional flotation. Small-scale flotation tests were performed in the laboratory and on-site with fine coal slurry samples from the plant thickener underflow, i.e., the washing plant`s undersized reject material. Flotation tests were conducted on-site with a 7.6-cm diameter Microcel{trademark} column and with small-scale conventional cells. Column flotation tests were performed to determine a recovery-grade relationship for the fine coal feed, which contained about 24% ash, and to obtain sufficient data to enable scale-up to a large-diameter unit. A primary objective was to establish the maximum throughput capacity of a Microcel flotation column while operating to produce a clean coal product with ash content of 7.5--7.8%. Results of the test work indicate that this product quality could be achieved at feed rates of 15--19 tph to a 3-m diameter Microcel flotation column. Lower ash products, i.e. 5--7% ash, were obtained but at lower column throughput capacities. Comparative flotation tests, conducted with conventional flotation cells, indicated that a product ash of only 8% or greater was achieved in a single-stage test.

  20. New tool to manage coral reefs

    NASA Astrophysics Data System (ADS)

    Showstack, Randy

    The National Oceanic and Atmospheric Administration is making available a new tool for coral reef managers to monitor the cumulative thermal stress of several coral reefs around the world, including the Great Barrier Reef, and reefs by the Galapagos Islands, the agency announced on 25 February.The agency's "Degree Heating Weeks" product uses satellite-derived information to allow continuous monitoring of the extent and acuteness of thermal stress, which are key predictors of coral bleaching, and which contribute to coral reef degradation.

  1. High performance O-ring sealed joints

    SciTech Connect

    Metcalfe, R.; Wensel, R.

    1994-02-01

    An integrated engineering approach to high performance sealing with O-rings is described. Sealing principles are explained, then used to illustrate the advantages of non-conventional geometries over handbook designs. The selection and qualification of optimal elastomer material for space shuttle applications is described, along with detection methods and rejection criteria for defects. The effects of lubrication, surface finish, squeeze, stretch and volume constraints are discussed in relation to O-rings in a nuclear pump seal. 7 refs., 12 figs.

  2. Improving the performance of conventional and column froth flotation cells

    SciTech Connect

    Arnold, B.J.

    1995-11-01

    Many existing mining operations hover on the brink of producing competitively priced fuel with marginally acceptable sulfur levels. To remain competitive, these operations need to improve the yield of their coal processing facilities, lower the sulfur content of their clean coal, or lower the ash content of their clean coal. Fine coal cleaning processes offer the best opportunity for coal producers to increase their yield of high quality product. Over 200 coal processing plants in the U.S. already employ some type of conventional or column flotation device to clean fines. an increase in efficiency in these existing circuits could be the margin required to make these coal producers competitive.

  3. Analyzing Protein-Phosphoinositide Interactions with Liposome Flotation Assays.

    PubMed

    Busse, Ricarda A; Scacioc, Andreea; Schalk, Amanda M; Krick, Roswitha; Thumm, Michael; Khnel, Karin

    2016-01-01

    Liposome flotation assays are a convenient tool to study protein-phosphoinositide interactions. Working with liposomes resembles physiological conditions more than protein-lipid overlay assays, which makes this method less prone to detect false positive interactions. However, liposome lipid composition must be well-considered in order to prevent nonspecific binding of the protein through electrostatic interactions with negatively charged lipids like phosphatidylserine. In this protocol we use the PROPPIN Hsv2 (homologous with swollen vacuole phenotype 2) as an example to demonstrate the influence of liposome lipid composition on binding and show how phosphoinositide binding specificities of a protein can be characterized with this method. PMID:26552682

  4. The kinetics of fossil resin extraction from a flotation concentrate

    SciTech Connect

    Li, L.; Yu, Q.; Miller, J.D.

    1995-11-01

    The kinetics of fossil resin extraction from a flotation concentrate by heptane were investigated as a function of process variables using monosize particles. Experimental results provide for a better understanding of the refining process and the basis for subsequent design and construction of a continuous resin refining circuit. Based on the effect of process variables (particle size, stirring speed, and temperature) the resin extraction rate appears to be controlled by surface solvation phenomena. The initial extraction rate was found to be inversely proportional to the initial particle size and a kinetic model is being developed to describe the experimental results.

  5. Coal surface control for advanced fine coal flotation

    SciTech Connect

    Fuerstenau, D.W.; Hanson, J.S.; Diao, J.; Harris, G.H.; De, A.; Sotillo, F. ); Somasundaran, P.; Harris, C.C.; Vasudevan, T.; Liu, D.; Li, C. ); Hu, W.; Zou, Y.; Chen, W. ); Choudhry, V.; Shea, S.; Ghosh, A.; Sehgal, R. )

    1992-03-01

    The initial goal of the research project was to develop methods of coal surface control in advanced froth flotation to achieve 90% pyritic sulfur rejection, while operating at Btu recoveries above 90% based on run-of-mine quality coal. Moreover, the technology is to concomitantly reduce the ash content significantly (to six percent or less) to provide a high-quality fuel to the boiler (ash removal also increases Btu content, which in turn decreases a coal's emission potential in terms of lbs SO{sub 2}/million Btu). (VC)

  6. Biomining: metal recovery from ores with microorganisms.

    PubMed

    Schippers, Axel; Hedrich, Sabrina; Vasters, Jürgen; Drobe, Malte; Sand, Wolfgang; Willscher, Sabine

    2014-01-01

    Biomining is an increasingly applied biotechnological procedure for processing of ores in the mining industry (biohydrometallurgy). Nowadays the production of copper from low-grade ores is the most important industrial application and a significant part of world copper production already originates from heap or dump/stockpile bioleaching. Conceptual differences exist between the industrial processes of bioleaching and biooxidation. Bioleaching is a conversion of an insoluble valuable metal into a soluble form by means of microorganisms. In biooxidation, on the other hand, gold is predominantly unlocked from refractory ores in large-scale stirred-tank biooxidation arrangements for further processing steps. In addition to copper and gold production, biomining is also used to produce cobalt, nickel, zinc, and uranium. Up to now, biomining has merely been used as a procedure in the processing of sulfide ores and uranium ore, but laboratory and pilot procedures already exist for the processing of silicate and oxide ores (e.g., laterites), for leaching of processing residues or mine waste dumps (mine tailings), as well as for the extraction of metals from industrial residues and waste (recycling). This chapter estimates the world production of copper, gold, and other metals by means of biomining and chemical leaching (bio-/hydrometallurgy) compared with metal production by pyrometallurgical procedures, and describes new developments in biomining. In addition, an overview is given about metal sulfide oxidizing microorganisms, fundamentals of biomining including bioleaching mechanisms and interface processes, as well as anaerobic bioleaching and bioleaching with heterotrophic microorganisms. PMID:23793914

  7. 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

  8. A deep reef in deep trouble

    USGS Publications Warehouse

    Menza, Charles; Kendall, M.; Rogers, C.; Miller, J.

    2007-01-01

    The well-documented degradation of shallower reefs which are often closer to land and more vulnerable to pollution, sewage and other human-related stressors has led to the suggestion that deeper, more remote offshore reefs could possibly serve as sources of coral and fish larvae to replenish the shallower reefs. Yet, the distribution, status, and ecological roles of deep (>30 m) Caribbean reefs are not well known. In this report, an observation of a deep reef which has undergone a recent extensive loss of coral cover is presented. In stark contrast to the typical pattern of coral loss in shallow reefs, the deeper corals were most affected. This report is the first description of such a pattern of coral loss on a deep reef.

  9. A deep reef in deep trouble

    NASA Astrophysics Data System (ADS)

    Menza, C.; Kendall, M.; Rogers, C.; Miller, J.

    2007-10-01

    The well-documented degradation of shallower reefs which are often closer to land and more vulnerable to pollution, sewage and other human-related stressors has led to the suggestion that deeper, more remote offshore reefs could possibly serve as sources of coral and fish larvae to replenish the shallower reefs. Yet, the distribution, status, and ecological roles of deep (>30 m) Caribbean reefs are not well known. In this report, an observation of a deep reef which has undergone a recent extensive loss of coral cover is presented. In stark contrast to the typical pattern of coral loss in shallow reefs, the deeper corals were most affected. This report is the first description of such a pattern of coral loss on a deep reef.

  10. Ores and Climate Change - Primary Shareholders

    NASA Astrophysics Data System (ADS)

    Stein, Holly J.; Hannah, Judith L.

    2015-04-01

    Many in the economic geology community concern themselves with details of ore formation at the deposit scale, whether tallying fluid inclusion data to get at changes in ore-forming fluids or defining structures that aid and abet mineralization. These compilations are generally aimed at interpretation of events at the site of ore formation, with the goal being assignment of the deposit to a sanctioned ore deposit model. While providing useful data, this approach is incomplete and does not, by itself, serve present-day requirements for true interdisciplinary science. The ore-forming environment is one of chaos and disequilibrium at nearly all scales (Stein, 2014). Chaos and complexity are documented by variably altered rocks, veins or disseminated mineralization with multi-generational fluid histories, erratic and unusual textures in host rocks, and the bitumen or other hydrocarbon products entwined within many ore deposits. This should give pause to our drive for more data as a means to find "the answer". The answer lies in the kind of data collected and more importantly, in the way we interpret those data. Rather than constructing an ever-increasing catalog of descriptive mutations on sanctioned ore deposit models (e.g., IOGC or Iron-Oxide Copper Gold deposits), the way forward is to link source and transport of metals, sulfur, and organic material with regional and ultimately whole Earth chemical evolution. Important experimental work provides chemical constraints in controlled and behaved environments. To these data, we add imagination and interpretation, always tying back to field observations. In this paper, several key points are made by way of ore deposit examples: (1) many IOCG deposits are outcomes of profound changes in the chemistry of the Earth's surface, in the interplay of the atmosphere, hydrosphere, biosphere, and lithosphere; (2) the redox history of Fe in deep earth may be ultimately expressed in the ore-forming sequence; and (3) the formation of many giant Cu-Mo-Au ore deposits may be arrested when the surface is catastrophically breached, as multiple km-scale breccia pipes empty their volatile and metal contents into the atmosphere. The new equation for studying ore geology should be one that reconstructs ore formation from beginning to end, that is, from source, release, and transport, to breach. Of course, detailed measurements and mapping of ore bodies remains essential, but a full understanding of metal migration and budgets can only be achieved if we model what might have been left behind in deeper Earth, and what may have been lost to the atmosphere. To do this, we need to understand much more than the geology at our ore deposit of interest. Stein, H.J. (2014) Dating and Tracing the History of Ore Formation. Treatise on Geochemistry 13: 87-118. Elsevier. Support for time to think - CHRONOS, funded by a consortium of Norwegian petroleum companies.

  11. High Latitude Reefs: A Potential Refuge for Reef Builders

    NASA Astrophysics Data System (ADS)

    Amat, A.; Bates, N.

    2003-04-01

    Coral reefs globally show variable signs of deterioration or community structure changes due to a host of anthropogenic and natural factors. In these global scenarios, rates of calcification by reef builders such as Scleractinian corals are predicted to significantly decline in the future due to the increase in atmospheric CO_2. When considering the response of reefs to the present climate change, temperature effects should also be taken into account. Here, we investigate the simultaneous impact of temperature and CO_2 on the high-latitude Bermuda coral reef system (32^oN, 64^oE)through a series of in vitro experiments at different CO_2 levels and seasonally different summer (27^oC) and winter (20^oC) temperature conditions. Four species of Scleractinian corals (Porites astreoides, Diploria labyrinthiformis, Madracis mirabilis and decactis) were acclimated for three months at: 20^oC and 27^oC (both with CO_2 levels at 400 ppm (control) and 700 ppm). Growth was assessed by buoyant weight techniques during the acclimation period. Photosynthesis, respiration and calcification were measured at the end of this period using respirometric chambers. A reproduction experiment was also undertaken under 27^oC. Photosynthesis mainly remains constant or increases under high CO_2 conditions. The results of the integrated calcification measurements confirm the hypothesis that an increase in CO_2 induces a decrease in calcification. However an increase in photosynthesis can be observed when CO_2 is unfavorable for calcification suggesting that a biological control of calcification through photosynthesis could prevent a drop in the calcification potential. Buoyant weight results indicate that the CO_2 impact could be less detrimental under lower temperature. This result will be compared with the instantaneous calcification measurements in the chambers and some in situ coral growth assessments in winter and summer conditions. The consequences for the response of marginal reefs undergoing high seasonal temperature variations will finally be discussed.

  12. Mid-late Holocene Reef Growth and Sedimentation History at Inshore Fringing Reefs in the Central Great Barrier Reef, Australia

    NASA Astrophysics Data System (ADS)

    Ryan, E.; Smithers, S.; Lewis, S.; Zhao, J. X.; Clark, T.

    2014-12-01

    Inshore coral reefs of Australia's Great Barrier Reef (GBR) are threatened by terrestrial sediment loads that are argued to have increased by five to six times since coastal catchments were settled by Europeans in the mid-1850s. Nutrient and contaminant delivery to the inshore GBR has also increased over this period. However, direct evidence that European colonisation has changed the ecology of inshore reefs on the GBR remains limited, partly due to a lack of baseline historical data on coral reef growth. Coral reefs have been growing in inshore areas of the GBR since 6 or 7 ky BP, and have experienced natural fluctuations in terrestrial sediment loads over this period. For example, floods associated with episodic cyclones and major rainfall events often deliver pulses of sediment, especially if they follow prolonged dry spells. To better understand this history of sediment influx and reef development, we have examined in detail the chronostratigraphy of several inshore GBR reefs that have grown since the mid-Holocene. Here, we report on eight percussion cores collected at Bramston Reef (148°15'E, 20°03'S). Two cores terminate in the pre-Holocene substrate and therefore capture the entire Holocene sequence of both reef framework and terrigenous sediment matrix. Results from detailed core analyses indicate variable sedimentation patterns throughout the period of reef development. Furthermore, reef ecological condition and variability through the mid-late Holocene is described using palaeoecological analyses. We explore the impacts of sedimentation variability on reef growth and ecology, and compare reef ecological condition pre- and post-European colonisation.

  13. Quantifying Coral Reef Ecosystem Services

    EPA Science Inventory

    Coral reefs have been declining during the last four decades as a result of both local and global anthropogenic stresses. Numerous research efforts to elucidate the nature, causes, magnitude, and potential remedies for the decline have led to the widely held belief that the recov...

  14. Sandstone Spire in Capitol Reef

    USGS Multimedia Gallery

    A view of a sandstone spire in Capitol Reef National Park. This area, known as the Fruita, is made up of three primary layers. The bottom sandstone layer is known as the Moenkopi Formation and is about 245 million years old. The middle gray-green layer is known as the Chinle Formation and was laid d...

  15. The future of coral reefs

    NASA Astrophysics Data System (ADS)

    Knowlton, Nancy

    2001-05-01

    Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived "weedy" corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1C, a likely result of global climate change, can cause coral "bleaching" (the breakdown of coral-algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent.

  16. Antimony ore in the Fairbanks district, Alaska

    USGS Publications Warehouse

    Killeen, Pemberton Lewis; Mertie, John B., Jr.

    1951-01-01

    Antimony-bearing ores in the Fairbanks district, Alaska, are found principally in two areas, the extremities of which are at points 10 miles west and 23 miles northeast of Fairbanks; and one of two minor areas lies along this same trend 30 miles farther to the northeast. These areas are probably only local manifestations of mineralization that affected a much broader area and formed antimony-bearing deposits in neighboring districts, the closest of which is 50 miles away. The ores were exposed largely as a result of lode gold mining, but at two periods in the past, high prices for antimony ore warranted an independent production and about 2500 tons of stibnite ore was shipped. The sulfide deposits occupy the same fractures along which a gold-quartz mineralization of greater economic importance occurred; and both are probably genetically related to igneous rocks which intrude the schistose country rock. The sulfide is in part contemporaneous with some late-stage quartz in which it occurs as disseminated crystals; and in part the latest filling in the mineralized zones where it forms kidney-shaped masses of essentially solid sulfide. One extremely long mass must have contained nearly 100 tons of ore, but the average of the larger kidneys is closer to several tons. Much of the ore is stibnite, with quartz as a minor impurity, and assays show the tenor to vary from 40 to 65 percent antimony. Sulphantimonites are less abundant but likewise occur as disseminated crystals and as kidney-shaped bodies. Antimony oxides appear on the weathered surface and along fractures within the sulfide ore. Deposits containing either stibnite or sulphantimonite are known at more than 50 localities, but only eighteen have produced ore and the bulk of this came from the mines. The geology of the deposit, and the nature, extent, and period of the workings are covered in the detailed descriptions of individual occurrences. Several geologic and economic factors, which greatly affect prospecting and mining for stibnite ore in the area, are outlined. The principal available ore and reserves are considered to be ores earlier mined but never shipped, ore minable from near-surface deposits, and ores recoverable as a by-product of future gold mining. The outlook for stibnite production in the district is very uncertain. Apparently the greater portion of stibnite ore has already been recovered and present operations will strip the two principal areas of the district. This conclusion is based on the scanty discoveries since the last war and the fact that the areas are so pock-marked with prospects that there is little likelihood that any other large near-surface bodies remain to be discovered. Future prospecting would essentially be limited to attempts to seek the continuation of lodes previously having high yields of stibnite.

  17. Inclusion flotation-driven channel segregation in solidifying steels

    PubMed Central

    Li, Dianzhong; Chen, Xing-Qiu; Fu, Paixian; Ma, Xiaoping; Liu, Hongwei; Chen, Yun; Cao, Yanfei; Luan, Yikun; Li, Yiyi

    2014-01-01

    Channel segregation, which is featured by the strip-like shape with compositional variation in cast materials due to density contrast-induced flow during solidification, frequently causes the severe destruction of homogeneity and some fatal damage. An investigation of its mechanism sheds light on the understanding and control of the channel segregation formation in solidifying metals, such as steels. Until now, it still remains controversial what composes the density contrasts and, to what extent, how it affects channel segregation. Here we discover a new force of inclusion flotation that drives the occurrence of channel segregation. It originates from oxide-based inclusions (Al2O3/MnS) and their sufficient volume fraction-driven flotation becomes stronger than the traditionally recognized inter-dendritic thermosolutal buoyancy, inducing the destabilization of the mushy zone and dominating the formation of channels. This study uncovers the mystery of oxygen in steels, extends the classical macro-segregation theory and highlights a significant technological breakthrough to control macrosegregation. PMID:25422943

  18. Nanoparticle flotation collectors--the influence of particle softness.

    PubMed

    Yang, Songtao; Razavizadeh, Bi Bi Marzieh; Pelton, Robert; Bruin, Gerard

    2013-06-12

    The ability of polymeric nanoparticles to promote glass bead and pentlandite (Pn, nickel sulfide mineral) attachment to air bubbles in flotation was measured as a function of the nanoparticle glass transition temperature using six types of nanoparticles based on styrene/N-butylacrylate copolymers. Nanoparticle size, surface charge density, and hydrophobicity were approximately constant over the series. The ability of the nanoparticles to promote air bubble attachment and perform as flotation collectors was significantly greater for softer nanoparticles. We propose that softer nanoparticles were more firmly attached to the glass beads or mineral surface because the softer particles had a greater glass/polymer contact areas and thus stronger overall adhesion. The diameters of the contact areas between polymeric nanoparticles and glass surfaces were estimated with the Young-Laplace equation for soft, liquidlike particles, whereas JKR adhesion theory was applied to the harder polystyrene particles. The diameters of the contact areas were estimated to be more than an order of magnitude greater for the soft particles compared to harder polystyrene particles. PMID:23692163

  19. Inclusion flotation-driven channel segregation in solidifying steels.

    PubMed

    Li, Dianzhong; Chen, Xing-Qiu; Fu, Paixian; Ma, Xiaoping; Liu, Hongwei; Chen, Yun; Cao, Yanfei; Luan, Yikun; Li, Yiyi

    2014-01-01

    Channel segregation, which is featured by the strip-like shape with compositional variation in cast materials due to density contrast-induced flow during solidification, frequently causes the severe destruction of homogeneity and some fatal damage. An investigation of its mechanism sheds light on the understanding and control of the channel segregation formation in solidifying metals, such as steels. Until now, it still remains controversial what composes the density contrasts and, to what extent, how it affects channel segregation. Here we discover a new force of inclusion flotation that drives the occurrence of channel segregation. It originates from oxide-based inclusions (Al2O3/MnS) and their sufficient volume fraction-driven flotation becomes stronger than the traditionally recognized inter-dendritic thermosolutal buoyancy, inducing the destabilization of the mushy zone and dominating the formation of channels. This study uncovers the mystery of oxygen in steels, extends the classical macro-segregation theory and highlights a significant technological breakthrough to control macrosegregation. PMID:25422943

  20. Initial testing of a dynamic column for fine coal flotation

    SciTech Connect

    Lai, R.W.; Patton, R.A.; He, D.X.; Joyce, T.; Chiang, S.H.

    1995-12-31

    This paper describes the design and initial performance of a dynamic column for fine coal column flotation. A dynamic column is a modified conventional column with the insertion of a series of draft tubes that provide individual mixing stages. The mixing is beneficial in generating small and uniform bubbles over a wide range of frother dosages. It is also beneficial in the control of flotation where the fluctuation of froth volume should be minimized. In the modified design, a vortex-inducing plate is attached to the top of each draft tube to create an artificial vortex. In theory the vortex action is desirable for collecting the light clean coal froth within the inner mixing zone, and for passing it upward to the next draft tube stage. The mineral laden slurry, particularly the pyrite, is accelerated outside the vortex zone by centrifugal force to reach the wall where it is carried downward to the bottom of the column. The draft tubes are arranged in a series to accomplish multistage cleaning. The experimental results showed that this dynamic column has the potential advantage of higher throughput and better product recovery as well as improved product quality.

  1. A Novel Mineral Flotation Process Using Thiobacillus ferrooxidans

    PubMed Central

    Nagaoka, Toru; Ohmura, Naoya; Saiki, Hiroshi

    1999-01-01

    Oxidative leaching of metals by Thiobacillus ferrooxidans has proven useful in mineral processing. Here, we report on a new use for T. ferrooxidans, in which bacterial adhesion is used to remove pyrite from mixtures of sulfide minerals during flotation. Under control conditions, the floatabilities of five sulfide minerals tested (pyrite, chalcocite, molybdenite, millerite, and galena) ranged from 90 to 99%. Upon addition of T. ferrooxidans, the floatability of pyrite was significantly suppressed to less than 20%. In contrast, addition of the bacterium had little effect on the floatabilities of the other minerals, even when they were present in relatively large quantities: their floatabilities remained in the range of 81 to 98%. T. ferrooxidans thus appears to selectively suppress pyrite floatability. As a consequence, 77 to 95% of pyrite was removed from mineral mixtures while 72 to 100% of nonpyrite sulfide minerals was recovered. The suppression of pyrite floatability was caused by bacterial adhesion to pyrite surfaces. When normalized to the mineral surface area, the number of cells adhering to pyrite was significantly larger than the number adhering to other minerals. These results suggest that flotation with T. ferrooxidans may provide a novel approach to mineral processing in which the biological functions involved in cell adhesion play a key role in the separation of minerals. PMID:10427053

  2. High-rate dissolved air flotation for water treatment.

    PubMed

    Reall, M A; Marchetto, M

    2001-01-01

    This paper presents the results of an experimental investigation about the performance of a horizontal flow high-rate pilot scale Dissolved Air Flotation (HRDAF) unit containing inclined parallel plates for treating a coloured and low turbidity raw water. Experiments were performed with the DAF unit in order to verify the influence on flotation of: (i) the water velocity (Vh) between the plates, in the range 18 to 96.5 cm.min-1 with corresponding Reynolds numbers between 240 and 1060; (ii) the supplied air (S*) value ranging from 2.2 to 8.5 g of air/m3 of water; (iii) the angle of the plates (60 degrees or 70 degrees). The best pilot plant operational condition was obtained applying only 4.0 g/m3 (S*) with Vh around 18 cm.min-1 for treatment of water coagulated with a Al2(SO4)3 dosage of 40 mg.l-1. In these conditions, the unit presented very good removal efficiencies of colour (90%, residual of 10 uC), turbidity (88%, residual of 0.8 NTU) and TSS (94%, residual of 1.8 mg.l-1). Furthermore, the unit could operate at higher Vh values up to 76 cm.min-1 and still present good results. The DAF unit thus behaved as a high rate unit presenting good performance with low air requirement. PMID:11394278

  3. Enhanced desulfurizing flotation of coal using sonoelectrochemical method.

    PubMed

    Zhang, Hong-Xi; Hou, Xiao-Yang; Xu, Shi-Xun; Li, Zhi-Long; Yu, Hai-Feng; Shen, Xue-Hua

    2013-09-01

    Enhanced desulfurizing flotation of low sulfur coal was investigated using sonoelectrochemical method. The supporting electrolyte used in this process was sodium chloride and the additive was anhydrous ethanol. The effects of treatment conditions on desulfurization were studied by a single-factor method. The conditions include anhydrous ethanol concentration, sodium chloride concentration, sonoelectrolytic voltage, sonoelectrolytic temperature, sonoelectrolytic time and coal sample granulometry. The optimal experimental conditions achieved for anhydrous ethanol concentration, sodium chloride concentration, sonoelectrolytic voltage, sonoelectrolytic temperature and sonoelectrolytic time are 1.7 mol L(-1), 5.110(-3) mol L(-1), 10 V, 70 C, 50 min achieved for a -0.18 mm coal sample. Optimal conditions cause a sulfur reduction of up to 69.4%. The raw and treated coals were analyzed by infrared spectroscopy and a chemical method. Pyritic sulfur, organic sulfur, ash as well as moisture are partially removed. The combination of high sulfur reduction, high yield, as well as high ash reduction was obtained in the newly developed method of enhanced flotation by sonoelectrochemistry. Ultrasound irradiation promotes electron transfer efficiency and increases clean coal yield. PMID:23558374

  4. The dynamic behavior of coarse particles in flotation froths

    SciTech Connect

    Van Dyk, W.A.; Van Deventer, J.S.J.; Lorenzen, L.

    1995-12-31

    Hydrophobic particles with diameters between 1 and 3 mm are poorly recovered by conventional flotation techniques. A novel reverse flotation technique is described whereby coarse particles with surfaces rendered highly hydrophobic, repel the bubble films in a froth and thus drop through the froth under gravity, to be recovered as a sink product. Conversely, gangue or hydrophilic particles are supported by the bubble films in the froth and are therefore recovered as a floating product. Tracer tests were conducted in the cell in order to study the dynamic behavior of solid particles in the froth. The effects of hydrophobicity, density, particle size and particle shape were investigated experimentally. The higher the hydrophobicity of the particles, the lower the recovery of particles as a floating product, while the recovery of particles as a sink product increases with an increase in particle density. Furthermore, a decrease in particle size results in an increase recovery of hydrophobic particles as a floating product. When treating particles of the same mass-to-surface-area ratio in the froth, flat particles would be recovered as a floating product in preference to cubic, disc-shaped, cylindrical and spherical particles, in that order.

  5. Inclusion flotation-driven channel segregation in solidifying steels

    NASA Astrophysics Data System (ADS)

    Li, Dianzhong; Chen, Xing-Qiu; Fu, Paixian; Ma, Xiaoping; Liu, Hongwei; Chen, Yun; Cao, Yanfei; Luan, Yikun; Li, Yiyi

    2014-11-01

    Channel segregation, which is featured by the strip-like shape with compositional variation in cast materials due to density contrast-induced flow during solidification, frequently causes the severe destruction of homogeneity and some fatal damage. An investigation of its mechanism sheds light on the understanding and control of the channel segregation formation in solidifying metals, such as steels. Until now, it still remains controversial what composes the density contrasts and, to what extent, how it affects channel segregation. Here we discover a new force of inclusion flotation that drives the occurrence of channel segregation. It originates from oxide-based inclusions (Al2O3/MnS) and their sufficient volume fraction-driven flotation becomes stronger than the traditionally recognized inter-dendritic thermosolutal buoyancy, inducing the destabilization of the mushy zone and dominating the formation of channels. This study uncovers the mystery of oxygen in steels, extends the classical macro-segregation theory and highlights a significant technological breakthrough to control macrosegregation.

  6. Removal of cadmium (II) from simulated wastewater by ion flotation technique

    PubMed Central

    2013-01-01

    A separation technique which has recently received a sharp increase in research activities is ion flotation. This technique has four important advantages for treating wastewaters: low energy consumption, small space requirements, small volume of sludge and acting selectively. The present study aims to optimize parameters of ion flotation for cadmium removal in simulated wastewater at laboratory scale. It was obtained on the reaction between Cd2+ and sodium dodecylesulfate (SDS) collector followed by flotation with ethanol as frother. Test solution was prepared by combining the required amount of cadmium ion, SDS and necessary frother or sodium sulfate solution. All experiments were carried out in a flotation column at laboratory temperature (27C), adjusted pH = 4 and 120minutes. The different parameters (namely: flow rate, cadmium, SDS and frother concentrations and ionic strength) influencing the flotation process were examined. The best removal efficiency obtained at a collector-metal ratio of 3:1 in 60min with flow rate of 150mL/min was 84%. The maximum cadmium removal was 92.1% where ethanol was introduced at a concentration 0.4% to flotation column with above conditions. The obtained results were promising, as both cadmium and collector were effectively removed from wastewater. Hence, the application of ion flotation for metal ions removal from effluents seems to be efficient. PMID:23388386

  7. Egg flotation estimates nest age for Pacific and Red-throated Loons

    USGS Publications Warehouse

    Rizzolo, D.J.; Schmutz, J.A.

    2007-01-01

    We used Pacific Loon (Gavia pacifica) and Red-throated Loon (G. stellata) nests with known ages to gauge the efficacy of egg flotation for determining nest age in coastal Alaska. Egg flotation accurately estimated nest age for both species; the mean ?? 1SD difference between known age and age determined with egg flotation was - 0.05 ?? 2.00 d and -0.02 ?? 1.63 d for Pacific and Red-throated Loons, respectively. Day of nest initiation did not influence the relationship between known nest age and nest age estimated with egg flotation, indicating incubation period was not shortened in nests initiated later in the season. Additionally, we found no difference in the ability of egg flotation to estimate nest age between two widely dispersed study sites for Pacific Loons, and only a small difference between two of three widely dispersed study sites for Red-throated Loons. Thus, our described relationships between egg flotation categories and nest age should be broadly applicable for these holarctic species. We conclude that for Pacific and Red-throated Loons, egg flotation is a useful technique for determining nest age in the field to better monitor nest fate, and to quantify nest age effects on nest daily survival rate.

  8. New evidence for the barrier reef model, Permian Capitan Reef complex, New Mexico

    SciTech Connect

    Kirkland, B.L.; Moore, C.H. Jr. )

    1990-05-01

    Recent paleontologic and petrologic observations suggest that the Capitan Formation was deposited as an organic or ecologic reef that acted as an emergent barrier to incoming wave energy. In outcrops in the Guadalupe Mountains and within Carlsbad Caverns, massive reef boundstone contains a highly diverse assemblage of frame-building and binding organisms. In modern reefs, diversity among frame builders decreases dramatically with depth. Marine cement is abundant in reef boundstone, but limited in back-reef grainstone and packstone. This cementation pattern is similar to that observed in modern emergent barrier reef systems. Based on comparison with modern analogs, these dasycladrominated back-reef sediments and their associated biota are indicative of shallow, hypersaline conditions. Few of these dasyclads exhibit broken or abraded segments and some thallus sections are still articulated suggesting that low-energy, hypersaline conditions occurred immediately shelfward of the reef. In addition, large-scale topographic features, such as possible spur and groove structures between Walnut Canyon and Rattlesnake Canyon, and facies geometries, such as the reef to shelf transition, resemble those found in modern shallow-water reefs. The organisms that formed the Capitan Reef appear to have lived in, and responded to, physical and chemical conditions similar to those that control the geometry of modern shallow-water reefs. Like their modern counterparts, they seem to have strongly influenced adjacent environments. In light of this evidence, consideration should be given to either modifying or abandoning the marginal mound model in favor of the originally proposed barrier reef model.

  9. Battelle developing reefs to ease habitat losses

    SciTech Connect

    Not Available

    1993-04-01

    Artificial reefs may be the answer to solving a worldwide problem of declining fish habitats, or they may only be good for creating fishing spots. Researchers at Battelle's Ocean Sciences Laboratory in Duxbury, Massachusetts, are studying artificial reefs in the Delaware River to determine if they are a solution to habitat losses in estuaries and coastal regions. [open quotes]Right now, we don't know if the fish are using the reefs simply as a grazing land, and then moving on, or if they're using the areas to colonize,[close quotes] said researcher Karen Foster. [open quotes]Ultimately, we hope to find they are colonizing.[close quotes] In 1989, Battelle researchers placed 16 prefabricated concrete reefs 45 feet deep in Delaware Bay. The reefs were placed in clusters of four, and monitoring began the following year. The federal government ordered the reefs placed in the bay as a mitigation technique for fish habitat that was lost when the river was dredged for navigational purposes. Researchers examined the reefs twice last summer. It will take five years, Foster said, before researchers can determine if the reefs are increasing the fish population. Early tests show, however, the populations of mussels, sponges, corals, and anemones increased by up to 150 percent over an area of bay bottom where the reefs were placed. Divers take crustacean samples from the reefs, and fish are caught near the reefs for examination. Researchers dissect the fish stomachs and analyze the contents to determine if they have been feeding at the reefs. [open quotes]If we find blue mussels in the stomach of the fish, that's great because we know that blue mussels are growing on the reef,[close quotes] Foster said.

  10. Biological models for Mesozoic reef evolution

    SciTech Connect

    Kauffman, E.G. )

    1990-11-01

    Throughout the Mesozoic, shallow-water carbonate ramps and platforms of the circumequatorial Tethyan Ocean were characterized by extensive development of reef ecosystems, especially during times of eustatic highstand, expansion of the Tropics, and warm equable global climates. The greatest reef development was north of the paleoequator in the Caribbean and Indo-Mediterranean provinces. These reefs and associated debris facies comprise major petroleum reservoirs, in some cases with remarkable porosity and permeability normally attributed to a combination of sedimentologic, tectonic, and diagenetic factors. The biological evolution of Mesozoic reefs also has had an important, and in some cases dominant, role in determining reservoir quality. Three major biological factors are critical to mesozoic reef-associated reservoir development: (1) the replacement/competitive displacement of coral-algal dominated, highly integrated reef ecosystems by loosely packed rudistid bivalve-dominated reef ecosystems in the Barremian-Albian; (2) the evolution of dominantly aragonitic, highly porous shells among framework-building rudistids in the middle and Late Cretaceous; and (3) competitive strategies among rudistids that effectively prevented widespread biological binding of Cretaceous reefs, leading to the production of large marginal fans that comprise major carbonate reservoirs. Detailed studies of these evolutionary trends in reef/framework development and of the distribution of different groups of bioconstructors on reefs lead to predictive modeling for primary and secondary porosity development in mesozoic carbonate reservoirs. The competitive displacement of coral-algal communities by rudistids on Cretaceous reefs was so effective that, even after Maastrichtian mass extinction of rudistids and other important groups comprising Mesozoic reef/carbonate platform ecosystems, coral-algal reef-building communities did not evolve again until the late Eocene.

  11. Kinetic model for conventional flotation of coal. Report of investigations/1995

    SciTech Connect

    Susko, F.J.; Stanley, D.A.

    1995-12-31

    The U.S. Bureau of Mines has developed a computer model to describe a flotation process. Coal data from conventional flotation has been converted to a simple two-parameter kinetic model developed by Reuter and van Deventer. Each set of coal data was represented by two constants, alpha and beta, and an average flotation rate. The success of the model was demonstrated when the calculated and experimental recoveries showed good correlation. The two-parameter model allows complex data to be defined much more efficiently than traditional knowledge-based models.

  12. Hydrophobic Agglomeration of Mineral Fines in Aqueous Suspensions and its Application in Flotation: a Review

    NASA Astrophysics Data System (ADS)

    Yang, Bingqiao; Song, Shaoxian

    2014-05-01

    Hydrophobic agglomeration is originated from the hydrophobic attraction between particles, which is essentially different from electrolyte coagulation and polymer flocculation. It is applied to mineral processing in floc-flotation process to improve the recovery of mineral fines. In this paper, the applications of this phenomenon in mineral fines were summarized, including the origin of hydrophobic agglomeration, the main factors affect hydrophobic agglomeration (particle hydrophobicity, shear rate and duration, nonpolar oil and tank geometry), as well as hydrophobic agglomeration based separation processes (carrier flotation and floc-flotation).

  13. Machine vision system for ore sizing

    NASA Astrophysics Data System (ADS)

    Eichelberger, Christopher L.; Blair, Steven M.; Khorana, Brij M.

    1991-03-01

    A machine vision systelu has been developed to size and count ore as it passes down a conveyor belt. The imaging system consists of a line scan camera a zoom lens and a structured lighting arrangenient. The structured lighting produces a line of light which is projected onto the conveyor belt at an angle with respect to the caniera. When a piece of ore is present the line of light covering the piece is displaced out of the field of view of the camera. This method is used to overcome the poor contrast between the ore and the conveyor belt. Iniages are acquired using an iiaage processor which performs real-tiiae thresholding of the iraage before it is passed to a frame buffer. A coniputer progrant locates the ore pieces in the image and identifies the boundaries between those pieces which are touching. Chords corresponding to the approximate major and minor axes of each piece are calculated. Using these measurements the size distribution for a population of ore is determined. 1.

  14. Coral reefs. Limited scope for latitudinal extension of reef corals.

    PubMed

    Muir, Paul R; Wallace, Carden C; Done, Terence; Aguirre, J David

    2015-06-01

    An analysis of present-day global depth distributions of reef-building corals and underlying environmental drivers contradicts a commonly held belief that ocean warming will promote tropical coral expansion into temperate latitudes. Using a global data set of a major group of reef corals, we found that corals were confined to shallower depths at higher latitudes (up to 0.6 meters of predicted shallowing per additional degree of latitude). Latitudinal attenuation of the most important driver of this phenomenon-the dose of photosynthetically available radiation over winter-would severely constrain latitudinal coral range extension in response to ocean warming. Latitudinal gradients in species richness for the group also suggest that higher winter irradiance at depth in low latitudes allowed a deep-water fauna that was not viable at higher latitudes. PMID:26045436

  15. Delineating optimal settlement areas of juvenile reef fish in Ngederrak Reef, Koror state, Republic of Palau.

    PubMed

    Ticzon, Victor S; Foster, Greg; David, Laura T; Mumby, Peter J; Samaniego, Badi R; Madrid, Val Randolf

    2015-01-01

    Establishing the effectiveness of habitat features to act as surrogate measures of diversity and abundance of juvenile reef fish provides information that is critical to coral reef management. When accurately set on a broader spatial context, microhabitat information becomes more meaningful and its management application becomes more explicit. The goal of the study is to identify coral reef areas potentially important to juvenile fishes in Ngederrak Reef, Republic of Palau, across different spatial scales. To achieve this, the study requires the accomplishment of the following tasks: (1) structurally differentiate the general microhabitat types using acoustics; (2) quantify microhabitat association with juvenile reef fish community structure; and (3) conduct spatial analysis of the reef-wide data and locate areas optimal for juvenile reef fish settlement. The results strongly suggest the importance of branching structures in determining species count and abundance of juvenile reef fish at the outer reef slope of Ngederrak Reef. In the acoustic map, the accurate delineation of these features allowed us to identify reef areas with the highest potential to harbor a rich aggregation of juvenile reef fish. Using a developed spatial analysis tool that ranks pixel groups based on user-defined parameters, the reef area near the Western channel of Ngederrak is predicted to have the most robust aggregation of juvenile reef fish. The results have important implications not only in management, but also in modeling the impacts of habitat loss on reef fish community. At least for Ngederrak Reef, the results advanced the utility of acoustic systems in predicting spatial distribution of juvenile fish. PMID:25394769

  16. Astronaut Photography of Coral Reefs

    NASA Technical Reports Server (NTRS)

    Robinson, Julie A.; Noordeloos, Marco

    2001-01-01

    Astronaut photographs of tropical coastal areas may contain information on submerged features, including coral reefs, up to depths of about 15 m in clear waters. Previous research efforts have shown that astronaut photographs can aid in estimating coral reef locations and extent on national, regional and global scales, and allow characterization of major geomorphological rim and lagoon features (Andrefouet et al. 2000, in preparation). They can be combined with traditional satellite data to help distinguish between clouds and lagoon features such as pinnacles (Andrefouet and Robinson, in review). Furthermore, astronaut photographs may provide reef scientists and managers with information on the location and extent of river plumes and sediment run off, or facilitate identification of land cover types, including mangroves (Webb et al., in press). Photographs included in the section were selected based on several criteria. The primary consideration of the editors was that the photographs represent a worldwide distribution of coral reefs, have extremely low visual interference by cloud cover, and display a spatial scale reasonable for examining reef-related features. Once photographs were selected, they were digitized from 2nd generation copies. The color and contrast were hand corrected to an approximation of natural color (required to account for spectral differences between photographs due to the color sensitivities of films used, and differences in sun angle and exposure of the photographs). None of the photographs shown here have been georeferenced to correct them to a map projection and scale. Any distortions in features due to slightly oblique look angles when the photographs were taken through spacecraft windows remain. When feasible, near vertical photographs have been rotated so that north is toward the top. An approximate scale bar and north arrow have added using distinctive features on each photograph with reference to a 1:1,000,000 scale navigation chart. Astronaut photographs provide a unique source of moderate resolution reef remote sensing data because of their global coverage and (immediate) availability in the public domain. The database of photographs can be searched an browsed online and high-resolution digital copies of photographs in this atlas can be accessed via the Website of Earth Science and Image Analysis at NASA's Johnson Space Center:

  17. Dynamic fragility of oceanic coral reef ecosystems

    PubMed Central

    Graham, Nicholas A. J.; Wilson, Shaun K.; Jennings, Simon; Polunin, Nicholas V. C.; Bijoux, Jude P.; Robinson, Jan

    2006-01-01

    As one of the most diverse and productive ecosystems known, and one of the first ecosystems to exhibit major climate-warming impacts (coral bleaching), coral reefs have drawn much scientific attention to what may prove to be their Achilles heel, the thermal sensitivity of reef-building corals. Here we show that climate change-driven loss of live coral, and ultimately structural complexity, in the Seychelles results in local extinctions, substantial reductions in species richness, reduced taxonomic distinctness, and a loss of species within key functional groups of reef fish. The importance of deteriorating physical structure to these patterns demonstrates the longer-term impacts of bleaching on reefs and raises questions over the potential for recovery. We suggest that isolated reef systems may be more susceptible to climate change, despite escaping many of the stressors impacting continental reefs. PMID:16709673

  18. Mineral chemical study of U-bearing minerals from the Dominion Reefs, South Africa

    NASA Astrophysics Data System (ADS)

    Rantzsch, Ulrike; Gauert, Christoph D. K.; van der Westhuizen, Willem A.; Duhamel, Isabelle; Cuney, Michel; Beukes, Gerhard J.

    2011-02-01

    The Neo-Archean Dominion Reefs (~3.06 Ga) are thin meta-conglomerate layers with concentrations of U- and Th-bearing heavy minerals higher than in the overlying Witwatersrand Reefs. Ore samples from Uranium One Africa's Rietkuil and Dominion exploration areas near Klerksdorp, South Africa, were investigated for their mineral paragenesis, texture and mineral chemical composition. The ore and heavy mineral assemblages consist of uraninite, other uraniferous minerals, Fe sulphides, Ni-Co sulfarsenides, garnet, pyrite, pyrrhotite, monazite, zircon, chromite, magnetite and minor gold. Sub-rounded uraninite grains occur associated with the primary detrital heavy mineral paragenesis. U-Ti, U-Th minerals, pitchblende (colloform uraninite) and coffinite are of secondary, re-mobilised origin as evidenced by crystal shape and texture. Most of the uranium mineralisation is represented by detrital uraninite with up to 70.2 wt.% UO2 and up to 9.3 wt.% ThO2. Re-crystallised phases such as secondary pitchblende (without Th), coffinite, U-Ti and U-Th phases are related to hydrothermal overprint during low-grade metamorphism and are of minor abundance.

  19. ReefLink Database: A decision support tool for Linking Coral Reefs and Society Through Systems Thinking

    EPA Science Inventory

    Coral reefs provide the ecological foundation for productive and diverse fish and invertebrate communities that support multibillion dollar reef fishing and tourism industries. Yet reefs are threatened by growing coastal development, climate change, and over-exploitation. A key i...

  20. Pearl and Hermes Reef, Hawaiian Island Chain

    NASA Technical Reports Server (NTRS)

    1992-01-01

    Pearl and Hermes Reef (28.0N, 176.0W) in the Hawaiian Island Chain, are seen with several small sandy islands, forming an atoll that caps a seamount on the long chain that extends some 1,500 miles northwestward from the more familiar Hawaiian Islands proper. Pearl and Hermes Reef lies about 100 miles southeast of Midway island. A reticulate network of coral patch reefs separates the lagoon into more or less isolated pools.

  1. Habitat heterogeneity reflected in mesophotic reef sediments

    NASA Astrophysics Data System (ADS)

    Weinstein, D. K.; Klaus, J. S.; Smith, T. B.

    2015-11-01

    Modern reef sediments reflect the physical and chemical characteristics of the environment as well as the local reef fauna. Analysis of sedimentary reef facies can thus provide a powerful tool in interpreting ancient reef deposits. However, few studies have attempted to differentiate sedimentary facies in mesophotic coral ecosystems, low light habitats defined as residing 30-150 m below sea level. The low-angle shelf mesophotic coral ecosystem south of the northern U.S. Virgin Islands (USVI) consists of reefs with different structural characteristics ideal for studying the relationship between habitat variability and sedimentary facies. Textural, compositional, and geochemical analyses of surface sediments were used to identify mesophotic reef subfacies associated with distinct benthic communities and structural habitats. Sediment grain composition and bulk geochemistry were found to broadly record the distribution and abundance of coral and macroalgae communities, foundational mesophotic reef benthic organisms. Overall, sediment composition was found to be a good indicator of specific reef environments in low-angle mesophotic reef habitats. Sedimentological analyses indicate that hydrodynamic forces do not transport a significant amount of allochthonous sediment or potentially harmful terrigenous material to USVI mesophotic reefs. Episodic, maximum current velocities prevented deposition of most silt-size grains and smaller, but biological processes were found to have a greater influence on subfacies partitioning than hydrodynamic processes. Results provide a new analog for studies of ancient mesophotic coral ecosystem geological history and document the relationship between mesophotic reef subfacies, structural complexity, and habitat heterogeneity. They also demonstrate how mesophotic reefs along the same shelf system do not always share similar sedimentary characteristics and thus record a diverse set of ecological and environmental conditions.

  2. Geological Approaches to Coral Reef Ecology

    NASA Astrophysics Data System (ADS)

    Kench, Paul

    2008-09-01

    Tropical coral reef systems cover an estimated 284,300 square kilometers of the Earth's surface and are considered among the most valuable ecosystems on Earth. The reef systems are zones of high biological diversity, habitat for about one quarter of all known marine species, and important components of the global carbon cycle. In addition, they provide the physical foundation for a number of mid-ocean nation states. Coral reefs worldwide are considered to be in serious ecological decline due to anthropogenic impacts, natural stresses, and climate change. However, these gloomy projections for coral reefs are based largely on analysis of short-term changes in their ecological condition.

  3. Studies on the Great Barrier Reef

    SciTech Connect

    Walton, S.

    1985-01-01

    Proposals to drill for oil on Australia's Great Barrier Reef have led to the appointment of a royal commission to study the environmental impact of such activities. The Australian Institute of Marine Science has developed a 5-part research plant which covers the Australian mangrove environment; nearshore habitat; processes and interactions, energy flows, resource cycling and their consequences within the reef ecosystems; patterns, abundances and relationships within the reef; and the continental shelf of the Great Barrier Reef region. Research in each of these areas is described.

  4. Onondage pinnacle reefs in New York State

    SciTech Connect

    Friedman, G.M.

    1995-09-01

    Onondaga pinnacle reefs, part of the Onondaga Formation, developed in an epeiric setting of the lowermost Middle Devonian (Eifelian). The reefs were initiated as coral-crinoidal mounds in the Edgecliff Member of the formation. Whereas most Devonian reefs are composed of rugose corals. Coral is the predominant kind of fossil, followed by crinoids, brachiopods, mollusks, undifferentiated skeletal debris, and possible sponges. The initial mineralogy of the corals is inferred to have been calcite. The porosity of these reefs is almost unique among reef reservoirs. most reefs produce from secondary or diagenetic porosity; by contrast Onondaga reefs display primary intracoralline or framework porosity. Between framework builders and/or skeletal particles cryptocrystalline/microcrystalline cement fills pores. As observed in modern reefs this kind of cement resembles micrite, but probable formed as high-magnesian calcite in a high-energy setting. Syntaxial or rim cement common lines crinoid particles. Some of these pinnacle reefs, formerly gas producers, are presently under development as gas-storage reservoirs.

  5. Conservation, precaution, and Caribbean reefs

    NASA Astrophysics Data System (ADS)

    Aronson, Richard B.; Precht, William F.

    2006-08-01

    Some authors argue that overfishing is an important reason that reef corals have declined in recent decades. Their reasoning is that overfishing removes herbivores, releasing macroalgae to overgrow and kill the corals. The evidence suggests, however, that global climate change and emergent marine diseases make a far greater contribution to coral mortality, and that macroalgae generally grow on the exposed skeletal surfaces of corals that are already dead. Macroalgal dominance, therefore, is an effect rather than a cause of coral mortality. Marine protected areas (MPAs), which are usually established to protect stocks of reef fish, foster populations of herbivorous fish under at least some circumstances. Increased herbivory can reduce algal cover, potentially accelerating the recovery of coral populations inside MPAs; however, establishing MPAs will have only a limited impact on coral recovery unless policymakers confront the accelerating negative effects of the global-scale sources of coral mortality.

  6. Impacts of Artificial Reefs on Surrounding Ecosystems

    NASA Astrophysics Data System (ADS)

    Manoukian, Sarine

    Artificial reefs are becoming a popular biological and management component in shallow water environments characterized by soft seabed, representing both important marine habitats and tools to manage coastal fisheries and resources. An artificial reef in the marine environment acts as an open system with exchange of material and energy, altering the physical and biological characteristics of the surrounding area. Reef stability will depend on the balance of scour, settlement, and burial resulting from ocean conditions over time. Because of the unstable nature of sediments, they require a detailed and systematic investigation. Acoustic systems like high-frequency multibeam sonar are efficient tools in monitoring the environmental evolution around artificial reefs, whereas water turbidity can limit visual dive and ROV inspections. A high-frequency multibeam echo sounder offers the potential of detecting fine-scale distribution of reef units, providing an unprecedented level of resolution, coverage, and spatial definition. How do artificial reefs change over time in relation to the coastal processes? How accurately does multibeam technology map different typologies of artificial modules of known size and shape? How do artificial reefs affect fish school behavior? What are the limitations of multibeam technology for investigating fish school distribution as well as spatial and temporal changes? This study addresses the above questions and presents results of a new approach for artificial reef seafloor mapping over time, based upon an integrated analysis of multibeam swath bathymetry data and geoscientific information (backscatter data analysis, SCUBA observations, physical oceanographic data, and previous findings on the geology and sedimentation processes, integrated with unpublished data) from Senigallia artificial reef, northwestern Adriatic Sea (Italy) and St. Petersburg Beach Reef, west-central Florida continental shelf. A new approach for observation of fish aggregations associated with Senigallia reef based on the analysis of multibeam backscatter data in the water column is also explored. The settlement of the reefs and any terrain change are investigated over time providing a useful description of the local hydrodynamics and geological processes. All the artificial structures (made up by water-based concrete for Senigallia reef and mainly steel for St. Petersburg Beach reef) are identified and those showing substantial horizontal and/or vertical movements are analyzed in detail. Most artificial modules of Senigallia reef are not intact and scour signatures are well depicted around them, indicating reversals of the local current. This is due to both the wind pattern and to the quite close arrangement of the reef units that tend to deflect the bottom flow. As regards to the St. Petersburg Beach reef, all the man-made steel units are still in their upright position. Only a large barge shows a gradual collapse of its south side, and presents well-developed scouring at its east-northeast side, indicating dominant bottom flow from west-southwest to east-northeast. While an overall seafloor depth shallowing of about 0.30 m from down-current deposits was observed for Senigallia reef, an overall deepening of about 0.08 m due to scour was observed at the St. Petersburg Beach reef. Based on the backscatter data interpretation, surficial sediments are coarser in the vicinities of both artificial reefs than corresponding surrounding sediments. Scouring reveals this coarser layer underneath the prevalent mud sediment at Senigallia reef, and the predominant silt sediment at St. Petersburg Beach reef. In the ten years of Senigalia reef study, large-scale variations between clay and silt appear to be directly linked to large flood events that have occurred just prior to the change. As regards the water column investigation, acoustic backscatter from fish aggregations gives detailed information on their morphology and spatial distribution. In addition, relative fish biomass estimates can be extrapolated. Results suggest that most of

  7. Froth flotation of oil-bearing metal sulfide wastes

    SciTech Connect

    Miller, R.L.; Atwood, R.L.; Ye, Yi

    1991-12-01

    An industrial wastewater, including plating wastes, is treated with sodium sulfide and ferrous sulfate to form a sulfide-oxide precipitate containing chromium and other toxic metals. Hydrocarbons, in the water, coat the sulfide-oxide particles, impeding metal recovery. Froth flotation, without reagent addition, was found to recover 93.9% of the solids from the sludge with simultaneous rejection of 89% of the water. Methyl isobutyl carbinol (MIBC) improved recovery and potassium amyl xanthate improved both recovery and grade. The process design has wastewater feed (without MIBC) to the rougher circuit. The rougher concentrate is conditioned with MIBC and fed to a cleaner circuit to achieve a high grade concentrate. About 95% of the water is recirculated to the waste treatment plant. 3 refs., 3 figs., 4 tabs.

  8. Froth flotation of oil-bearing metal sulfide wastes

    SciTech Connect

    Miller, R.L. ); Atwood, R.L.; Ye, Yi )

    1991-01-01

    An industrial wastewater, including plating wastes, is treated with sodium sulfide and ferrous sulfate to form a sulfide-oxide precipitate containing chromium and other toxic metals. Hydrocarbons, in the water, coat the sulfide-oxide particles, impeding metal recovery. Froth flotation, without reagent addition, was found to recover 93.9% of the solids from the sludge with simultaneous rejection of 89% of the water. Methyl isobutyl carbinol (MIBC) improved recovery and potassium amyl xanthate improved both recovery and grade. The process design has wastewater feed (without MIBC) to the rougher circuit. The rougher concentrate is conditioned with MIBC and fed to a cleaner circuit to achieve a high grade concentrate. About 95% of the water is recirculated to the waste treatment plant. 3 refs., 3 figs., 4 tabs.

  9. Molecular loops in the galactic center: evidence for magnetic flotation.

    PubMed

    Fukui, Yasuo; Yamamoto, Hiroaki; Fujishita, Motosuji; Kudo, Natsuko; Torii, Kazufumi; Nozawa, Satoshi; Takahashi, Kunio; Matsumoto, Ryoji; Machida, Mami; Kawamura, Akiko; Yonekura, Yoshinori; Mizuno, Norikazu; Onishi, Toshikazu; Mizuno, Akira

    2006-10-01

    The central few hundred parsecs of the Milky Way host a massive black hole and exhibit very violent gas motion and high temperatures in molecular gas. The origin of these properties has been a mystery for the past four decades. Wide-field imaging of the (12)CO (rotational quantum number J = 1 to 0) 2.6-millimeter spectrum has revealed huge loops of dense molecular gas with strong velocity dispersions in the galactic center. We present a magnetic flotation model to explain that the formation of the loops is due to magnetic buoyancy caused by the Parker instability. The model has the potential to offer a coherent explanation for the origin of the violent motion and extensive heating of the molecular gas in the galactic center. PMID:17023654

  10. Hybrid first-principles/neural networks model for column flotation

    SciTech Connect

    Gupta, S.; Liu, P.H.; Svoronos, S.A.; Sharma, R.; Abdel-Khalek, N.A.; Cheng, Y.; El-Shall, H.

    1999-03-01

    A new model for phosphate column flotation is presented which for the first time relates the effects of operating variables such as frother concentration on column performance. This is a hybrid model that combines a first-principles model with artificial neural networks. The first-principles model is obtained from material balances on both phosphate particles and gangue (undesired material containing mostly silica). First-order rates of net attachment are assumed for both. Artificial neural networks relate the attachment rate constants to the operating variables. Experiments were conducted in a 6-in.-dia. (152-mm-dia.) laboratory column to provide data for neural network training and model validation. The model successfully predicts the effects of frother concentration, particle size, air flow rate and bubble diameter on grade and recovery.

  11. Development of new process and reagent for flotation of graphite

    SciTech Connect

    Deo, P.N.; Rao, G.M.

    1995-12-31

    Graphite is soft and easily floatable but it is quite difficult to obtain high purity concentrate at coarse sizes. Chemical treatment can produce high grade concentrate but it is an expensive process. Graphite containing plus 96% fixed carbon (FC) with coarse flakes commands a high price in the international market. Such graphite concentrate containing plus 96% FC was produced in Indian Bureau of Mines (IBM) by using newly developed reagent (mixture of different hydrocarbons and terpenes, IBM/D7) instead of commonly used frothers viz. pine oil, MIBC, kerosine etc. and regrinding in a special type of mill with special grinding media instead of grinding in a conventional ball/rod mill followed by cleaning. Both the new reagent (frother) and special grinding media are inexpensive and readily available. This paper focuses application of this new grinding methodology for flake size protection, and the new reagent for selective flotation of high purity graphite.

  12. Comparative evaluation of a modified zinc sulfate flotation technique.

    PubMed Central

    Bartlett, M S; Harper, K; Smith, N; Verbanac, P; Smith, J W

    1978-01-01

    A modified zinc sulfate flotation technique using Formalinized fecal specimens (F-ZnSO4) was compared to the Formalin-ether (FE) concentration method for the laboratory diagnosis of intestinal parasites. Many laboratories have difficulty storing, using, and disposing of either and need a procedure for concentrating fecal specimens which does not require ether. Comparative data were obtained for the recovery of protozoan cysts and helminth eggs and larvae from feces preserved in Formalin less than and longer than 1 month. Whereas the FE method was found generally to be more efficient, F-ZnSO4 was apparently more effective for the recovery of some species of parasites. F-ZnSO4 was not satisfactory for recovery of schistosome eggs. We conclude that, except for schistosomes, F-ZnSO4 compares favorably to the FE method for detecting infections of clinical significance. PMID:566767

  13. An Investigation of Variables in a Fecal Flotation Technique

    PubMed Central

    O'Grady, M. R.; Slocombe, J. O. D.

    1980-01-01

    Several variables in a standard vial fecal gravitational flotation technique were investigated. These were the specific gravity of the sodium nitrate flotation solution, duration of flotation and mesh sizes of strainers. The number of eggs which floated and adhered to a coverslip were counted and estimates of the number of eggs remaining in the strained fecal suspension and in the feces trapped on the strainer were made. Eggs from hookworms, Trichuris vulpis and Toxocara canis in feces from dogs, Nematodirus spp. from sheep and Parascaris equorum from horses floated equally well in solutions with specific gravities (SpGr) ranging from 1.22-1.38. Taenia spp. from dogs had a slightly narrower range (SpGr 1.27-1.38) for best recovery. Eggs from Haemonchus contortus from sheep appeared to float best between SpGr 1.22- 1.32. Strongyles from one horse floated best with SpGr 1.27-1.32 and from another with SpGr 1.11-1.38. Coccidial oocysts from sheep floated best in a narrow range of SpGr from 1.22-1.27. However, as the SpGr of the solution was increased the recognition of eggs under the coverslip was increasingly difficult and especially so at SpGr 1.38 with sheep feces. This was due to the increasing amount of debris and the more rapid formation of crystals with evaporation with solutions of higher SpGr. It appeared, therefore, that solutions with SpGr of 1.22-1.35 would be best for routine laboratory use. At specific gravity 1.27, there appeared to be no difference in the number of eggs recovered for a four, eight and 12 min flotation period. Only 3-7% of the eggs in 4 g of feces were counted under the coverslip. This poor efficacy resulted first because approximately 50% of the eggs were trapped in the feces and retained on the strainer. Secondly, only one half of the strained fecal suspension, containing approximately 25% of the eggs, was placed in the vial for examination. Thirdly, of those eggs in the vial only 16-29% were counted under the coverslip. When the second half of the strained fecal suspension was placed in another vial, the amount of debris and air bubbles adhering to the coverslip was much less than that for the first vial. Egg counts for both vials appeared similar and it may be that when debris is excessive the fecal examination should involve counts from a second vial. The use of strainers finer than the standard tea strainer and the addition of minimal amounts of detergent did not increase the egg count. PMID:7190861

  14. Rule-based characterization of industrial flotation processes with inductive techniques and genetic algorithms

    SciTech Connect

    Gouws, F.S.; Aldrich, C.

    1996-11-01

    By making use of machine learning techniques, the features of flotation froths and other plant variables can be used as a basis for the development of knowledge-based systems for plant monitoring and control. probabilistic induction and genetic algorithms were used to classify different froth structures from industrial copper and platinum flotation plants, as well as recoveries from a phosphate flotation plant. Both algorithms were equally capable of classifying the different froths at least as well as a human expert. The genetic algorithm performed significantly better than the inductive algorithm but required more tuning before optimum results could be obtained. The classification rules produced by both algorithms can easily be incorporated into a supervisory expert system shell or decision support system for plant operators and could consequently make a significant impact on the way flotation plants are currently being controlled.

  15. Achieved slime flotation in centrifugal force field by float-hydrocyclone

    SciTech Connect

    Guode Xuzhanxian; Gaozhenshen Songzhiwei

    1997-12-31

    Based on the theory of intensifying flotation in a centrifugal force field, float-hydrocyclone (FH) is developed, which is a new type of equipment for slime flotation and consists of an air bubble generator and the cylindrical section of a hydrocyclone. The combination of pulp and air bubbles is fed into the FH tangentially at a high speed to effect the separation of slime in the centrifugal force field. It offers many advantages over mechanically agitated flotation cells. Commercial test results show that slime, especially fine slime, can be perfectly floated in the FH with rapid flotation and fine froth size. The quality and quantity of concentrate and tailings can be adjusted conveniently within a certain range according to different requirements.

  16. 46 CFR 28.110 - Life preservers or other personal flotation devices.

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... be equipped with at least one immersion suit, exposure suit, or wearable personal flotation device of... commercial fishing activities must meet the requirements of this paragraph. (b) Each wearable...

  17. 46 CFR 28.110 - Life preservers or other personal flotation devices.

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... be equipped with at least one immersion suit, exposure suit, or wearable personal flotation device of... commercial fishing activities must meet the requirements of this paragraph. (b) Each wearable...

  18. 46 CFR 28.110 - Life preservers or other personal flotation devices.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... be equipped with at least one immersion suit, exposure suit, or wearable personal flotation device of... commercial fishing activities must meet the requirements of this paragraph. (b) Each wearable...

  19. Statistical evaluation and optimization of factors affecting the leaching performance of copper flotation waste.

    PubMed

    Coruh, Semra; Elevli, Sermin; Geyiki, Feza

    2012-01-01

    Copper flotation waste is an industrial by-product material produced from the process of manufacturing copper. The main concern with respect to landfilling of copper flotation waste is the release of elements (e.g., salts and heavy metals) when in contact with water, that is, leaching. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals, such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study is to investigate the leaching characteristics of copper flotation waste by use of the Box-Behnken experimental design approach. In order to obtain the optimized condition of leachability, a second-order model was examined. The best leaching conditions achieved were as follows: pH = 9, stirring time = 5 min, and temperature = 41.5 C. PMID:22629194

  20. Statistical Evaluation and Optimization of Factors Affecting the Leaching Performance of Copper Flotation Waste

    PubMed Central

    Çoruh, Semra; Elevli, Sermin; Geyikçi, Feza

    2012-01-01

    Copper flotation waste is an industrial by-product material produced from the process of manufacturing copper. The main concern with respect to landfilling of copper flotation waste is the release of elements (e.g., salts and heavy metals) when in contact with water, that is, leaching. Copper flotation waste generally contains a significant amount of Cu together with trace elements of other toxic metals, such as Zn, Co, and Pb. The release of heavy metals into the environment has resulted in a number of environmental problems. The aim of this study is to investigate the leaching characteristics of copper flotation waste by use of the Box-Behnken experimental design approach. In order to obtain the optimized condition of leachability, a second-order model was examined. The best leaching conditions achieved were as follows: pH = 9, stirring time = 5 min, and temperature = 41.5°C. PMID:22629194

  1. FOAM FLOTATION TREATMENT OF HEAVY METALS AND FLUORIDE-BEARING INDUSTRIAL WASTEWATERS

    EPA Science Inventory

    Laboratory studies demonstrated that the floc foam flotation techniques are effective in removing lead, cadmium, mercury, copper, zinc, arsenic, and fluoride from dilute wastewaters to very low levels. Simulated as well as real industrial wastewaters were studied. Industrial wast...

  2. The future of coral reefs

    PubMed Central

    Knowlton, Nancy

    2001-01-01

    Coral reefs, with their millions of species, have changed profoundly because of the effects of people, and will continue to do so for the foreseeable future. Reefs are subject to many of the same processes that affect other human-dominated ecosystems, but some special features merit emphasis: (i) Many dominant reef builders spawn eggs and sperm into the water column, where fertilization occurs. They are thus particularly vulnerable to Allee effects, including potential extinction associated with chronic reproductive failure. (ii) The corals likely to be most resistant to the effects of habitat degradation are small, short-lived “weedy” corals that have limited dispersal capabilities at the larval stage. Habitat degradation, together with habitat fragmentation, will therefore lead to the establishment of genetically isolated clusters of inbreeding corals. (iii) Increases in average sea temperatures by as little as 1°C, a likely result of global climate change, can cause coral “bleaching” (the breakdown of coral–algal symbiosis), changes in symbiont communities, and coral death. (iv) The activities of people near reefs increase both fishing pressure and nutrient inputs. In general, these processes favor more rapidly growing competitors, often fleshy seaweeds, and may also result in explosions of predator populations. (v) Combinations of stress appear to be associated with threshold responses and ecological surprises, including devastating pathogen outbreaks. (vi) The fossil record suggests that corals as a group are more likely to suffer extinctions than some of the groups that associate with them, whose habitat requirements may be less stringent. PMID:11344288

  3. Great Barrier Reef, Queensland, Australia

    NASA Technical Reports Server (NTRS)

    1991-01-01

    Along the coast of Queensland, Australia (18.0S, 147.5E), timbered foothills of the Great Dividing Range separate the semi-arid interior of Queensland from the farmlands of the coastal plains. Prominent cleared areas in the forest indicate deforestation for farm and pasture lands. Offshore, islands and the Great Barrier Reef display sand banks along the southern sides of the structures indicating a dominant southerly wind and current direction.

  4. Quantitative mineralogical characterization of chrome ore beneficiation plant tailing and its beneficiated products

    NASA Astrophysics Data System (ADS)

    Das, S. K.

    2015-04-01

    Mineralogical characterization and liberation of valuable minerals are primary concerns in mineral processing industries. The present investigation focuses on quantitative mineralogy, elemental deportment, and locking-liberation characteristics of the beneficiation of tailings from a chrome ore beneficiation plant in the Sukinda region, Odisha; methods used for the study of the beneficiated tailings are QEMSCAN®, X-ray diffraction (XRD), and mineral chemistry by a scanning electron microscope equipped with an energy-dispersive spectrometer (SEM-EDS). The tailing sample was fine grained (69.48wt% below 45 μm size), containing 20.25wt% Cr2O3 and 39.19wt% Fe2O3, with a Cr:Fe mass ratio of 0.51. Mineralogical investigations using QEMSCAN studies revealed that chromite, goethite, and gibbsite are the dominant mineral phases with minor amounts of hematite, kaolinite, and quartz. The sample contained 34.22wt% chromite, and chromite liberation is more than 80% for grains smaller than 250 μm in size. Based on these results, it was predicted that liberated chromite and high-grade middling chromite particles could be separated from the gangue by various concentration techniques. The tailing sample was beneficiated by hydrocyclone, tabling, wet high-intensity magnetic separation (WHIMS), and flotation in order to recover the chromite. A chromite concentrate with 45.29wt% Cr2O3 and a Cr:Fe mass ratio of 1.85 can be produced from these low-grade chromite ore beneficiation plant rejects.

  5. Stripping of VOC`s from dissolved air flotation

    SciTech Connect

    Parker, W.J.; Monteith, H.D.

    1996-12-31

    A pilot scale study was performed to assess gas phase emissions of volatile organic compounds (VOCs) from the dissolved air flotation process. A high degree of mass closure was observed in experiments using tapwater dosed with a cocktail of VOCs, indicating that techniques employed to characterize the pilot plant were valid. Subsequent dosed wastewater experiments examined volatilization from a wastewater matrix that contained oils and suspended solids as well as investigating the impacts of hydraulic loading and recycle rate on the fate of the VOCs in the dissolved air flotation unit. Emissions of the dosed candidate compounds, calculated as a percentage of the influent mass flow, ranged from 0.2% of 1,1,2,2-tetrachloroethane to 9.9% of tetrachloroethylene. Hydraulic loading and compounding type had a statistically significant effect on the emissions of VOCs, however, a high degree of interaction between parameters was observed. Effluent recycle had a greater effect on emissions at the higher hydraulic loading than at the lower loading. A model which incorporated stripping by bubbles, volatilization from a quiescent oil-free surface and equilibrium partitioning to oil was developed. The model was able to simulate the candidate compound response under all experimental conditions except the case with low hydraulic loading and low recycle rate. The results suggest that the surface volatilization model may underestimate emissions. It is hypothesized that the presence of a float in the form of a foamy layer with a high surface area tends to increase liquid-gas mass transfer of the candidate compounds over that assumed in the surface volatilization model. 13 refs., 6 figs., 8 tabs.

  6. Effects of particle size and chain length on flotation of quaternary ammonium salts onto kaolinite

    NASA Astrophysics Data System (ADS)

    Longhua, Xu; Yuehua, Hu; Faqin, Dong; Hao, Jiang; Houqin, Wu; Zhen, Wang; Ruohua, Liu

    2015-06-01

    Effects of particle size and chain length on flotation of quaternary ammonium salts (QAS) onto kaolinite have been investigated by flotation tests. Dodecyltrimethylammonium chloride (DTAC) and cetyltrimethylammonium chloride (CTAC) were used as collectors for kaolinite in different particle size fractions (0.075 ~ 0.01 mm, 0.045 ~ 0.075 mm, 0 ~ 0.045 mm). The anomalous flotation behavior of kaolinite have been further explained based on crystal structure considerations by adsorption tests and molecular dynamics (MD) simulation. The results show that the flotation recovery of kaolinite in all different particle size fractions decreases with an increase in pH. As the concentration of collectors increases, the flotation recovery increases. The longer the carbon chain of QAS is, the higher the recoveries of coarse kaolinite (0.075 ~ 0.01 mm and 0.045 ~ 0.075 mm) are. But the flotation recovery of the finest kaolinite (0 ~ 0.045 mm) decreases with chain lengths of QAS collectors increasing, which is consistent with the flotation results of unscreened kaolinite (0 ~ 0.075 mm). It is explained by the froth stability related to the residual concentration of QAS collector in mineral pulp. In lower residual concentration, the froth stability becomes worse. Within the range of flotation collector concentration, it's easy of CTAC to be completely adsorbed by kaolinite in the particle size fraction (0-0.045 mm), which led to lower flotation recovery. Moreover, it is interesting that the coarser particle size of kaolinite is, the higher flotation recovery is. The anomalous flotation behavior of kaolinite is rationalized based on crystal structure considerations. The results of MD simulations show that the (001) kaolinite surface has the strongest interaction with DTAC, compared with the (00 1) face, (010) and (110) edges. On the other hand, when particle size of kaolinite is altered, the number of basal planes and edge planes is changed. It is observed that the finer kaolinite particles size become, the greater relative surface area of edges and the more the number of edges are. It means that fine kaolinite particles have more edges to adsorb fewer cationic colletors than that of coarse kaolinite particles, which is responsible for the poorer floatability of fine kaolinite.

  7. Influence of reef geometry on wave attenuation on a Brazilian coral reef

    NASA Astrophysics Data System (ADS)

    Costa, Mirella B. S. F.; Araújo, Moacyr; Araújo, Tereza C. M.; Siegle, Eduardo

    2016-01-01

    This study presents data from field experiments that focus on the influence of coral reef geometry on wave transformation in the Metropolitan Area of Recife (MAR) on the northeast coast of Brazil. First, a detailed bathymetric survey was conducted, revealing a submerged reef bank, measuring 18 km long by 1 km wide, parallel to the coastline with a quasi-horizontal top that varies from 0.5 m to 4 m in depth at low tide. Cluster similarity between 180 reef profiles indicates that in 75% of the area, the reef geometry has a configuration similar to a platform reef, whereas in 25% of the area it resembles a fringing reef. Measurements of wave pressure fluctuations were made at two stations (experiments E1 and E2) across the reef profile. The results indicate that wave height was tidally modulated at both experimental sites. Up to 67% (E1) and 99.9% (E2) of the incident wave height is attenuated by the reef top at low tide. This tidal modulation is most apparent at E2 due to reef geometry. At this location, the reef top is only approximately 0.5 m deep during mean low spring water, and almost all incident waves break on the outer reef edge. At E1, the reef top depth is 4 m, and waves with height ratios smaller than the critical breaking limit are free to pass onto the reef and are primarily attenuated by bottom friction. These results highlight the importance of reef geometry in controlling wave characteristics of the MAR beaches and demonstrate its effect on the morphology of the adjacent coast. Implications of differences in wave attenuation and the level of protection provided by the reefs to the adjacent shoreline are discussed.

  8. Nocturnal relocation of adult and juvenile coral reef fishes in response to reef noise

    NASA Astrophysics Data System (ADS)

    Simpson, S. D.; Jeffs, A.; Montgomery, J. C.; McCauley, R. D.; Meekan, M. G.

    2008-03-01

    Juvenile and adult reef fishes often undergo migration, ontogenic habitat shifts, and nocturnal foraging movements. The orientation cues used for these behaviours are largely unknown. In this study, the use of sound as an orientation cue guiding the nocturnal movements of adult and juvenile reef fishes at Lizard Island, Great Barrier Reef was examined. The first experiment compared the movements of fishes to small patch reefs where reef noise was broadcast, with those to silent reefs. No significant responses were found in the 79 adults that were collected, but the 166 juveniles collected showed an increased diversity each morning on the reefs with broadcast noise, and significantly greater numbers of juveniles from three taxa (Apogonidae, Gobiidae and Pinguipedidae) were collected from reefs with broadcast noise. The second experiment compared the movement of adult and juvenile fishes to reefs broadcasting high (>570 Hz), or low (<570 Hz) frequency reef noise, or to silent reefs. Of the 122 adults collected, the highest diversity was seen at the low frequency reefs; and adults from two families (Gobiidae and Blenniidae) preferred these reefs. A similar trend was observed in the 372 juveniles collected, with higher diversity at the reefs with low frequency noises. This preference was seen in the juvenile apogonids; however, juvenile gobiids were attracted to both high and low sound treatments equally, and juvenile stage Acanthuridae preferred the high frequency noises. This evidence that juvenile and adult reef fishes orientate with respect to the soundscape raises important issues for management, conservation and the protection of sound cues used in natural behaviour.

  9. The Revised Coral Reef Hypothesis

    NASA Astrophysics Data System (ADS)

    Vecsei, A.; Berger, W. H.

    The original coral reef hypothesis stated that carbonate production by benthic biota on the world's shallow shelves substantially contributed to the buildup of atmospheric pCO2 during the last deglaciation. We have synthetized the literature on the world's reefs and new data on the distribution of the carbonate platforms (isolated banks and contintent-attached platforms). Strong production and resulting CO2 release started during the mid-deglaciation (~14 k.y.), and peaked during the early Holocene (~9-6 k.y) before Indopacific sealevel stabilized. We revise the coral reef hypothesis in that the carbonate production resulted in a strong positive feedback on the CO2 rise and warming during the late deglaciation. The estimated total production resulted in the release of >220 Gt carbon as CO2, corresponding to >105 p.p.m. pCO2 rise. This greatly exceeds the actual pCO2 rise since 14 k.y.. The known sinks in the terrestrial biosphere and the deep ocean appear insufficient for this carbon.

  10. AERIAL VIEW FACING EAST, LOOKING DOWN CENTER OF ORE YARD. ...

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

    AERIAL VIEW FACING EAST, LOOKING DOWN CENTER OF ORE YARD. OIL TANKS IN FOREGROUND, ORE BRIDGE & SINTERING CONVEYOR IN CENTER, & COKE PLANT IN BACKGROUND. - Pittsburgh Steel Company, Monessen Works, Donner Avenue, Monessen, Westmoreland County, PA

  11. 4. From west side of boat slip; ore piles, unloaders, ...

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

    4. From west side of boat slip; ore piles, unloaders, blast furnaces, tube conveyors, ore conveyors, stock house, powerhouse. Looking north/northeast - Rouge Steel Company, 3001 Miller Road, Dearborn, Wayne County, MI

  12. 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

  13. 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

  14. 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

  15. 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

  16. 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

  17. 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

  18. 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

  19. 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

  20. 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

  1. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The... an aluminum ore....

  2. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The... an aluminum ore....

  3. 40 CFR 440.20 - Applicability; description of the aluminum ore subcategory.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... aluminum ore subcategory. 440.20 Section 440.20 Protection of Environment ENVIRONMENTAL PROTECTION AGENCY... Aluminum Ore Subcategory § 440.20 Applicability; description of the aluminum ore subcategory. The... an aluminum ore....

  4. Pioneering studies on the flotation of corundum from a Montana gneiss

    SciTech Connect

    Smith, C.W.; Llewellyn, T.O.

    1987-01-01

    Bureau of Mines conducted laboratory-scale beneficiation tests on a sample of corundum gneiss from Montana to devise a method for beneficiating corundum for use as a substitute for refractory-grade bauxite. A flotation process utilizing petroleum sulfonate as the collector in an acid circuit was devised. Results showed that two flotation schemes each produced a concentrate exceeding the national stockpile specifications for calcined bauxite.

  5. Heavy metals in the products of deinking flotation of digital offset prints.

    PubMed

    Barbaric-Mikocevic, Zeljka; Orescanin, Visnja; Bolanca, Zdenka; Lulic, Stipe; Rozic, Mirela

    2004-01-01

    This study was undertaken to investigate the suitability of applying the conventional method of chemical deinking flotation of digital offset prints and ecological implications of the disposal of digital offset prints, with special emphasis on the content of heavy metal cations. The EDXRF method was used to determine the concentrations of Pb, Zr, Sr, As, Co, Zn, Cu, Ni, Fe, Mn, Cr, V, Ti, Ca, and K cations in handsheet ashes after flotation as well as in ashes of foams separated from cellulose suspension in the flotation phase. The same method was applied to determine the concentrations of Pb, Cr, Mn, Fe, Ni, Cu, Zn, and Co in process water filtrates obtained from the cellulose suspension after flotation and in foam filtrates. Centrifuging and coagulation previously treated flotation process water, while foam filtrates were centrifuged. Concentrations of Pb, As, Sr, Zr, K, Ca, Ti, V, Cr, Mn, Fe, Cu, and Zn were determined in the sediments obtained by centrifuging process water. The trials were done with unprinted substrates without deinking chemicals, with unprinted substrates in the presence of deinking chemicals and with printed substrates in the presence of deinking chemicals. Cation analysis revealed that deinking chemicals facilitate release of cations from the substrate and their transition into process water. Concentrations of most cations in the flotation process water, in foam water as well as in the sediment of the process water of printed substrate flotation deinking were lower than those obtained by flotation of unprinted substrate suspension. Polymer particles of ElectroInk incompletely separated from cellulose fibers prevent release of cations from cellulose fibers into process water. Deinking chemicals do not affect release of cations from ElectroInk particles, so the substrate is the main source of increased concentration of cations in the water of digital offset print deinking. The major part of cations in process water is bound to the colloid particles of the filler (CaCO3) released by substrate disintegration and to particles of fine fibers. PMID:15533011

  6. A study on evaluation method of flotation frother`s froth stability

    SciTech Connect

    Xu Zhenhong; Zhu Jianhua; Zhang Rongzeng; Li Xi

    1998-12-31

    Frother plays an important role in the coal flotation. The frothability of common frothers for coal flotation was measured by using gas pulsation method in this paper. The relationship between froth height and half decay time was analyzed. In this article, several well-known frothability evaluation methods will have been analyzed and compared, and a new method of evaluating froth stability will be given.

  7. Simulation of flotation bank performances as a function of fineness of grind

    SciTech Connect

    Bazin, C.; Grant, R.; Duchesne, S.

    1995-12-31

    Grinding simulators are now widely available to assist in the selection of circuit operating conditions or flowsheet designs that yield a given product size distribution. These simulators do not inform of the impact of the grinding product size distribution on subsequent flotation stages. This paper presents a method to predict the effect of fineness of grind on a flotation bank operation. Application of the method is illustrated with data from two Canadian concentrators.

  8. Proceedings of the 19. international mineral processing congress: Flotation operating practices and fundamentals. Volume 3

    SciTech Connect

    1995-12-31

    The papers included here consist of a combination of state-of-the-art reviews, research in progress, and applications in practice chosen from more than 800 abstracts. The volume is divided into the following topical sections: plenary lectures; flotation fundamentals; flotation operating practice; and mineral reagents. Papers within the scope of energy production, utilization, or conversion have been processed separately for inclusion on the data base.

  9. A comparison of the influence of wetting heat with contact angle in flotation

    SciTech Connect

    Zhu Shuquan; Liu Bohong; Liu Yun; Wang Zuna

    1998-12-31

    Coal flotation yield is related to coal surface hydrophobicity. Contact angle is normally used as an index for floatability. This paper compares the influence of contact angle with wetting heat on flotation results from 16 Chinese coals with broad coalification range. It was found that the correlation of wetting heat is much better than that of contact angle in evaluation of coal floatability. Three levels of wetting heat values are proposed for classification of coal floatability.

  10. Thermal Barrier For Vented O-Ring Seal

    NASA Technical Reports Server (NTRS)

    Schick, H.; Shadlesky, Philip S.; Perry, Mark C.; Ketner, Donald M.; Salita, Mark

    1992-01-01

    Barrier allows gases to seat seal without damaging it. Ring of tungsten-wire mesh forms protective barrier between hot, pressurized combustion gases and O-rings. Mesh cools and depressurizes gases so they safely push on and thereby help to seat primary O-ring or secondary O-ring if primary O-ring fails to form seals. Barrier devised for use in rocket motor. Potential terrestrial applications includes aircraft engines, furnaces, and ducts carrying hot gases.

  11. Placement Of O-Rings In Solid Rocket Booster

    NASA Technical Reports Server (NTRS)

    Wood, Charles

    1991-01-01

    Brief report proposes to modify placement of O-ring seals in joints of Solid Rocket Booster of Space Shuttle. Modified joint and seal essentially "inside-out" version of old joint and seal. O-rings placed between outer side of tang and clevis. Joint rotation pushes tang harder against O-rings, thereby making even tighter seal. Proposal derived from analysis of Space Shuttle Challenger disaster, attributed to failure of these O-ring seals.

  12. 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

  13. Separation of polyethylene terephthalate from municipal waste plastics by froth flotation for recycling industry

    SciTech Connect

    Wang, Chong-Qing; Wang, Hui Liu, You-Nian

    2015-01-15

    Highlights: • Factors of NaOH treatment were studied by orthogonal and single factor experiments. • Mechanism of alkaline treatment for facilitating flotation was manifested. • Flotation separation of PET was achieved with high purity and efficiency. • A flow sheet of purification PET from MWP was designed. - Abstract: Recycling is an effective way to manage plastic wastes and receives considerable attention. Since plastic mixtures are difficult to recycle because of their intrinsic characteristics, separation of mixed plastics is the key problem for recycling. Separation of polyethylene terephthalate (PET) from municipal waste plastics (MWP) by froth flotation combined with alkaline pretreatment was investigated for recycling industry. The effect of process variables was estimated by L{sub 9} (3{sup 4}) orthogonal array of experiments and single factor experiments. The optimum conditions of alkaline pretreatment are 10 wt% sodium hydroxide, 20 min and 70 °C. After alkaline pretreatment under optimum conditions, flotation separation PET from acrylonitrile–butadiene–styrene, polystyrene, polycarbonate or polyvinyl chloride was achieved with high purity and efficiency. The purity of PET is up to 98.46% and the recovery is above 92.47%. A flow sheet of separation PET from MWP by a combination of froth flotation and sink float separation was designed. This study facilitates industrial application of plastics flotation and provides technical insights into recycling of waste plastics.

  14. The use of ion flotation for detoxification of metal-contaminated waters and process effluents

    SciTech Connect

    Doyle, F.M.; Duyvesteyn, S.; Sreenivasarao, K.

    1995-12-31

    Toxic metals entering surface or ground water from sources such as metal finishing shop spills and abandoned mines can pose a significant threat to public health and the environment. Ion flotation and similar foam separation techniques show great promise for treating dilute, metal-contaminated solutions, and could also be used to treat effluents from many minerals and metallurgical processing operations prior to discharge. In ion flotation, an appropriate collector is added to the solution to form hydrophobic complexes with the metal ions. These metal-bearing species are then removed by flotation, usually with trace addition of a frother to stabilize the foam. In an effort to better understand the underlying scientific and engineering principles that determine the performance of ion flotation, the removal of Cu(II), Pb(II), Cd(II), Cr(III) and Cr(VI) has been studied using laboratory scale flotation columns in batch mode. The effects of the superficial air velocity, solution and froth height, nature of the collector, collector:metal-ion ratio, ionic strength and several frothers at low concentrations on the flotation kinetics are reported. Finally, results are presented on methods that might allow regeneration of collector and recovery of by-product metal from the foam product.

  15. Sorbent flotation in trace metal analysis: Preconcentration of uranium traces on hydrophobized hyphan-cellulose

    SciTech Connect

    Braun, T.; Galsan, V.; Toelgyessy, J.

    1994-01-01

    The use of flotation in analytical chemistry has established itself as a reliable technique for the separation and preconcentration of trace elements. In most of the applications in situ generated inorganic and organic precipitates were used as trace element gatherers and floated to the surface of large volumes of solution with the aid of a rising stream of gas bubbles and well selected collector surfactants. This procedure of {open_quotes}precipitate flotation{close_quotes} has been well studied and applied to many problems of preconcentration chemistry. As far as the present authors are aware of solid preformed sorbents have not yet been separated from large volumes of solution by flotation after batch type sorption of trace elements on them. That is why the authors considered it worthwhile to explore the analytical potentialities of the separation of commercial and non-commercial solid sorbents by flotation. The new procedure the authors like to call {open_quotes}sorbent flotation{close_quotes} refers to the separation of preformed solid sorbents from large volumes of solution and can be viewed as an extension to the already known flotation of in situ formed inorganic and organic precipitates.

  16. Flotation separation of polyvinyl chloride and polyethylene terephthalate plastics combined with surface modification for recycling.

    PubMed

    Wang, Chongqing; Wang, Hui; Fu, Jiangang; Zhang, Lingling; Luo, Chengcheng; Liu, Younian

    2015-11-01

    Surface modification with potassium permanganate (KMnO4) solution was developed for separation of polyvinyl chloride (PVC) and polyethylene terephthalate (PET) waste plastics. The floatability of PVC decreases with increasing of KMnO4 concentration, treatment time, temperature and stirring rate, while that of PET is unaffected. Fourier transform infrared (FT-IR) analysis confirms that mechanism of surface modification may be due to oxidization reactions occurred on PVC surface. The optimum conditions are KMnO4 concentration 1.25 mM/L, treatment time 50 min, temperature 60°C, stirring rate 300 r/min, frother concentration 17.5 g/L and flotation time 1 min. PVC and PET with different particle sizes were separated efficiently through two-stage flotation. Additionally, after ultrasonic assisted surface modification, separation of PVC and PET with different mass ratios was obtained efficiently through one-stage flotation. The purity and the recovery of the obtained products after flotation separation are up to 99.30% and 99.73%, respectively. A flotation process was designed for flotation separation of PVC and PET plastics combined with surface modification. This study provides technical insights into physical separation of plastic wastes for recycling industry. PMID:26253330

  17. Mapping Oyster Reef Habitats in Mobile Bay

    NASA Technical Reports Server (NTRS)

    Bolte, Danielle

    2011-01-01

    Oyster reefs around the world are declining rapidly, and although they haven t received as much attention as coral reefs, they are just as important to their local ecosystems and economies. Oyster reefs provide habitats for many species of fish, invertebrates, and crustaceans, as well as the next generations of oysters. Oysters are also harvested from many of these reefs and are an important segment of many local economies, including that of Mobile Bay, where oysters rank in the top five commercial marine species both by landed weight and by dollar value. Although the remaining Mobile Bay oyster reefs are some of the least degraded in the world, projected climate change could have dramatic effects on the health of these important ecosystems. The viability of oyster reefs depends on water depth and temperature, appropriate pH and salinity levels, and the amount of dissolved oxygen in the water. Projected increases in sea level, changes in precipitation and runoff patterns, and changes in pH resulting from increases in the amount of carbon dioxide dissolved in the oceans could all affect the viability of oyster reefs in the future. Human activities such as dredging and unsustainable harvesting practices are also adversely impacting the oyster reefs. Fortunately, several projects are already under way to help rebuild or support existing or previously existing oyster reefs. The success of these projects will depend on the local effects of climate change on the current and potential habitats and man s ability to recognize and halt unsustainable harvesting practices. As the extent and health of the reefs changes, it will have impacts on the Mobile Bay ecosystem and economy, changing the resources available to the people who live there and to the rest of the country, since Mobile Bay is an important national source of seafood. This project identified potential climate change impacts on the oyster reefs of Mobile Bay, including the possible addition of newly viable habitats in the southeastern regions of the Bay.

  18. Coral reef evolution on rapidly subsiding margins

    USGS Publications Warehouse

    Webster, J.M.; Braga, J.C.; Clague, D.A.; Gallup, C.; Hein, J.R.; Potts, D.C.; Renema, W.; Riding, R.; Riker-Coleman, K.; Silver, E.; Wallace, L.M.

    2009-01-01

    A series of well-developed submerged coral reefs are preserved in the Huon Gulf (Papua New Guinea) and around Hawaii. Despite different tectonics settings, both regions have experienced rapid subsidence (2-6??m/ka) over the last 500??ka. Rapid subsidence, combined with eustatic sea-level changes, is responsible for repeated drowning and backstepping of coral reefs over this period. Because we can place quantitative constraints on these systems (i.e., reef drowning age, eustatic sea-level changes, subsidence rates, accretion rates, basement substrates, and paleobathymetry), these areas represent unique natural laboratories for exploring the roles of tectonics, reef accretion, and eustatic sea-level changes in controlling the evolution of individual reefs, as well as backstepping of the entire system. A review of new and existing bathymetric, radiometric, sedimentary facies and numerical modeling data indicate that these reefs have had long, complex growth histories and that they are highly sensitive, recording drowning not only during major deglaciations, but also during high-frequency, small-amplitude interstadial and deglacial meltwater pulse events. Analysis of five generalized sedimentary facies shows that reef drowning is characterized by a distinct biological and sedimentary sequence. Observational and numerical modeling data indicate that on precessional (20??ka) and sub-orbital timescales, the rate and amplitude of eustatic sea-level changes are critical in controlling initiation, growth, drowning or sub-aerial exposure, subsequent re-initiation, and final drowning. However, over longer timescales (> 100-500??ka) continued tectonic subsidence and basement substrate morphology influence broad scale reef morphology and backstepping geometries. Drilling of these reefs will yield greatly expanded stratigraphic sections compared with similar reefs on slowly subsiding, stable and uplifting margins, and thus they represent a unique archive of sea-level and climate changes, as well as a record of the response of coral reefs to these changes over the last six glacial cycles. ?? 2008 Elsevier B.V. All rights reserved.

  19. Rebound Of Previously Compressed O-Ring

    NASA Technical Reports Server (NTRS)

    Moore, Carleton J.

    1988-01-01

    Report presents theoretical and experimental analysis of relaxation characteristics of O-ring of vinylidene fluoride/hexafluoropropylene copolymer of same composition used in solid rocket boosters on Space Shuttle flight 51-L. Study covers range of temperatures from 10 to 120 degree F. Presents one-dimensional mathematical model of response provided for both elastic response and creep.

  20. Sources of ores of the ferroalloy metals

    USGS Publications Warehouse

    Burchard, E.F.

    1933-01-01

    Since all steel is made with the addition of alloying elements, the record of the metallic raw materials contributory to the steel industry would be far from complete without reference to the ferroalloy metals. This paper, therefore, supplements two preceding arvicles on the sources of our iron ores. The photographs, with the exception of those relating to molybdenum and vanadium, are by the author.