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oxidation of pyrite in coal to magnetite

reverse flotation of pyrite from a zinc - capabuild

The process of froth flotation entails crushing and grinding the ore to a fine size.Lime is often used to raise the pH of the pulp and also reduce the flotation of iron pyrite.The tailing from the lead flotation circuit is the feed to the zinc circuit. reverse flotation of pyrite from a zinc - hotelnewgreenview, More,

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Pyrite: Mineral information, data and localities. - Mindat

Decomposed pyrite concretion Pyrite will slowly oxidize, with the help of various bacteria, in a moist environment, and release sulfuric acid that is formed during the process. Well-crystallized specimens are generally relatively stable, while pyrite formed as sedimentary concretions has a tendency to decompose quickly.

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Mineralogy of Sulfides - Elements

Like pyrite oxidation, these are complex, multistage electrochemical reactions. Spectroscopic studies (Schaufuss et al. 2000; Corkhill et al. 2008) have shown that oxidation of As proceeds via a series of one-electron transfer steps, from As −1 to As 5+, with S oxidation considered as a 7-step reaction, transforming disulfide (S 2− ) to ...

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Thermal Behavior of Pyrite in the CO and N Atmosphere for ... - SciELO

These factors allow pyrite to transform into hematite, magnetite and/or pyrrhotite12. The phase changes promoted by thermal treatment of pyrite up to 800 ºC substantially increase its magnetization. These changes include the formation of magnetic phases such as pyrrhotite. In the thermal decomposition process, pyrite

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Ferric Sulphate Produced From Pyrite Concentrate of Coal Tailings to ...

from different coal pyrite tailings. The main variable studied was the concentration of pyrite in the material and its influence in the purity of the coagulant. Materials and Methods Coal Tailings Samples A pyrite concentrate from coal tailings obtained by jigging from "Cambuí Mine". Paraná State, Brazil, with 65 % FeS2 (FS B/ CT - 65% ...

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Method for oxidation of pyrite in coal to magnetite and low field ...

Method for oxidation of pyrite in coal to magnetite and low field magnetic separation. Full Record ...

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Kinetics of the oxidation reactions and decomposition of pyrite

Despite the great abundance of pyrite in nature and its role as one of the main sources of SO2 emissions in industrial processes, there is little definitive information about the kinetics and mechanisms of pyrite oxidation and decomposition reactions. This work aimed to determine the viability of applying the Friedman method for kinetic parameter determination to the oxidation and ...

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Petrology, mineralogy and environmental geochemistry of mined coal in ...

Natural oxidation of coal-pyrite took its natural course, forming hydrated sulfate minerals. Figure 4 shows the falling down of coal weathering products on mine floor. Accordingly, this may lead to the deterioration of groundwater quality. 3. Experimental Technique,

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Decomposition and oxidation of pyrite | Request PDF - ResearchGate

At lower temperatures (about 800K) or lower oxygen concentrations, pyrite will be transformed by a two-step process: the thermal decomposition of the pyrite to form porous pyrrhotite as the first...

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ZA893194B - Pyrite depressants useful in the separation of ... - Google

pyrite coal separation depressants useful useful Prior art date 1988-04-28 Application number ZA893194A Other languages English (en) Inventor Richard R Klimpel R Klimpel Richard Michael J Fazio J Fazio Michael Robert D Hansen D Hansen Robert Original Assignee Dow Chemical Co

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Oxidation of pyrite in coal to magnetite - USGS

Abstract When bituminous coal is heated in an inert atmosphere (He) containing small amounts of oxygen at 393-455 ??C, pyrite (FeS2) in coal is partially converted to magnetite (Fe304). The maximum amount of Fe304 formed during the time of heating corresponds to 5-20% of the total pyrite present, depending on the coal sample.

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Reprinted from COAL, Kural,O.,ed., Istanbul Tech. Univ., p. 253-269

magnetic susceptibility of pyrite over coal and in turn, facilitate the separation of pyrite by high gradient magnetic separation (Hall and Finch, 1984.). Desulphurization of lignites by ... oxidation of pyrite by bacteria such as Thiobacillus ferrooxidans to form water-soluble iron sulphate. The removal of pyritic

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SciELO - Brasil - Thermal Behavior of Pyrite in the CO 2 and N 2 ...

The phase changes promoted by thermal treatment of pyrite up to 800 ºC substantially increase its magnetization. These changes include the formation of magnetic phases such as pyrrhotite. In the thermal decomposition process, pyrite is transformed into pyrrhotite, and the FeS 2 grains become porous because of the loss of sulfur gas 13.

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Magnetic properties and metastability of greigite-smythite ...

Thermal treatment in oxidation conditions caused the most pronounced changes in magnetic parameters in a temperature range of 320-380°C, in which a laboratory process of self-reversal of remanence was observed. The products obtained during thermal treatment were identified with the aid of X-ray diffractographs (Co-radiation, Fe-filter).

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Microwave Roasting of Pyrite Tailings and Pyrite Ash for Sponge ... - Core

The effects of electric and magnetic fields in the microwave heater provide a very rapid movement generated with emitting (2.4 x 109 times per second) lead to particle heating ... In this investigation, the copper pyrite and coal pyrite was microwave roasted to oxidize both the other iron sulphide and even the pyrolysis of coal. The effects were

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Microbial communities in acid mine drainage - Oxford Academic

Acidic, metal-rich fluids are formed by chemical weathering of metal sulfide-rich rocks. These acid rock drainage (ARD) solutions are hot because metal sulfide oxidation reactions are highly exothermic. The predominant metal sulfide mineral in most rocks is pyrite (FeS 2 ). Pyrite-rich deposits are often mined for metals such as Au, Ag, Cu, Zn ...

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The Thermal Decomposition Behavior of Pyrite-Pyrrhotite Mixtures in ...

The pyrite begins to transform into monoclinic pyrrhotite at 500-600°C, and afterward, hexagonal pyrrhotite is observed at 700-800°C; at 900°C, more stable FeS is formed. Additionally, Wang et al. and Li et al. have applied magnetic technology to identify the thermal decomposition process of pyrite. The study shows that there are two ...

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Chemical Cleaning of Coal - ASME Digital Collection

Chemical Cleaning of Coal. J. Eng. Power. Jul 1977, 99 (3): 361-364 (4 pages) Between the expensive coal conversion processes and the relatively inexpensive flotation and magnetic methods for pyrite removal are the chemical methods for desulfurizing coal. Chemical cleaning removes more sulfur than physical separations, less than coal conversion ...

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Control of Sulfur Dioxide Emissions From Copper Smelters: Volume I ...

Previous Work Although extensive previous work on the steam oxidation of pyrite and neutral-roasted pyrite (pyrrhotite) was noted, essentially no such work directed at similar treatment of pyritic copper concentrates was uncovered. ... The HpS yield from the single particle will decrease with time as magnetite layer builds up and the pyrrhotite ...

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Thermal phase transition of pyrite from coal|INIS

[en] The thermal phase transition of pyrite from coal was studied using thermogravimetry and derivative thermogravimetric, infrared spectroscopy and X-ray diffraction (XRD). According to the XRD results, the phase transition of the pyrite starts at 350 °C, pyrrhotite and magnetite are intermediate products of the oxidation from pyrite to hematite.

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Catalytic combustion of coal and synthetic fuels. Technical progress report

The U.S. Department of Energy's Office of Scientific and Technical Information

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Transformation of Pyrite and Its Implication on Ash Deposition during ...

Role of pyrite in ash deposition Pyrite: FeS 2 Major Fe-containing mineral in coal Minor Fe-containing minerals such as siderite (FeCO 3 ), ankerite (CaFe(CO 3 2 Major source of Fe that contributes to ash slagging High content of Fe in ash deposits is often observed Excluded pyrite Pyrite transformation Included pyrite McLennan et al.

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Degradation of methyl orange by pyrite activated persulfate oxidation ...

Degradation mechanism of methyl orange (MO), a typical azo dye, with pyrite (FeS 2) activated persulfate (PS) was explored.The results showed that when the initial concentration of MO was 0.1 mM, FeS 2 was 1.6 g/L and PS was 1.0 mM, the removal rate of MO could reach 92.9% in 150 min, and the removal rate of total organic carbon could reach 14.1%. In addition, both pH ≤ 2 and pH ≥ 10 could ...

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c Copyright 2014 Akademiai Kiado, Budapest, Hungary Notice Changes ...

pyrite/marcasite with particle size 0.1-0.2 mm was first subjected to gravity separation to . 53 . remove the inclusions of coal using a laboratory mechanical pan (Micropaner). Then, the . 54 . obtained concentrate was cleaned by means of magnetic separation. The mineral composition . 55 . of the final product was estimated by X-ray diffraction ...

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Landscape to atomic scales: Researchers apply new approach to pyrite ...

A new, multi-scale approach to studying pyrite oxidation deep underground suggests that fracturing and erosion at the surface set the pace of oxidation, which, when it occurs slowly, avoids ...

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Study of Sulfur Behavior and Removal During Thermal Desul Furization of ...

Much of the coal in the Illinois Basin is high-sulfur coal, greater than 3 percent total sulfur, which limits its use as a fuel source. A substantial portion of the coal desul- furization research at the Illinois State Geological Sur- vey has been aimed at producing a clean low-sulfur solid fuel from Illinois high-sulfur coal. In this project

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10.1016/j.pecs.2005.11.004 | DeepDyve

The wide occurrence of pyrite in different minerals and coals makes it one of the main sources of SO 2 emission from various industrial activities, such as the metallurgical industry, power production and cement production. SO 2 is formed when pyrite is oxidized in industrial processes.

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Determination of minerals in coal by methods based on the recalculation ...

Using SEM-EDX (Fig. 2a) and image analysis (Fig. 3), only the presence of pyrite was proved (Table 3). In coal samples 1 to 4, grains of pyrite varied in size from about 1 to 400 [micro]n and pyrite content ranged from 0 to 17 %. In coal sample 5, the size of pyrite grains were below 15 [micro]m and its maximal content less than 0.16 %.

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Phase Transformation and Dissolution Behavior of Pyrite in the ... - MDPI

The selective leaching of vanadium and iron has been one of the main concerns in the field of vanadium recovery from stone coal, but the source of iron ions and their release characteristics were still unclear. In this work, the dissolution of pyrite and its roasted product, under conditions in accordance with the vanadium leaching process from stone coal by blank roasting-acid leaching, were ...

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Mechanisms of Pyrite Oxidation to Non-Slagging Species. Quartery ... - CORE

'Office of Scientific and Technical Information (OSTI)' Abstract This paper presents results of investigations on the transformation of iron pyrite to non-slagging species during staged combustion of pulverized coal. Work focuses on the oxidation of iron pyrite to magnetite Report Magnetite Pyrite Mathematical Models 01 Coal, Lignite, And Peat

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Iron oxidation by Thiobacillus ferrooxidans - Oregon State University

treatment of coal, low-grade ores and industrial solid ... A.2 Soluble Iron Concentration in Pyrite Oxidation by Different Strains of T. ferrooxidans 96 ... Pyrite(FeS2) Magnetite(Fe304) Ilmenite(FeOTi02) 4 Fe° + 2H+ ---> Fe2+ + H2 (1-1) Ferric iron precipitates in alkaline solution and

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Magnetic susceptibility measurements to detect coal fly ash from ... - UNCG

Oxidation of the pyrite (FeS 2 ) in pulverized coal at high temperatures produces molten iron spheres and sulfur, the iron oxidizes to form magnetite (Fe 3 O 4 ) and hematite (Fe 2 O 3 ) as common constituents in fly ash (Flanders, 1994).

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Philip L Walker Jr Papers - Pennsylvania State University

The Magnetokinetics of Oxidation of Pyrite, IEEE Transactions on Magnetics Vol MAG-12 889-891. Natural Graphite-CVD Carbon Composites, ... Investigation of Retrogressive Reactions Leading to the Carbonization of Solvent-Refined Coal, Fuel Vol 58 293-297. Magnetic and Catalytic Properties of Sintered Nickel Catalysts for the Methanation Reaction

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Mechanisms of Pyrite Oxidation to Non-Slagging Species

A project was undertaken to characterize the oxidation of iron pyrite to the non-slagging species magnetite during pulverized coal combustion. The work was aimed at defining the pyrite transformations responsible for the higher slagging propensity of staged, low-NO {sub x} pulverized coal combustor burners.

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COAL DESULFURIZATION |authorSTREAM

Precleaning coal: Reject 57.5% of the pyritic sulfur, 4.5% loss of heating value, Decreased the amount of coal treated in advanced column flotation to 48% of feed Advanced column flotation: Reject an additional 24.2% of the raw coal pyrite Overall, an 81.8% pyritic sulfur rejection with 90.2% combustible matter recovery The cost of cleaning was ...

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Oxidation of pyrite in coal to magnetite - ScienceDirect

When bituminous coal is heated in an inert atmosphere (He) containing small amounts of oxygen at 393-455 °C, pyrite (FeS 2) in coal is partially converted to magnetite (Fe 3 0 4).The maximum amount of Fe 3 0 4 formed during the time of heating corresponds to 5-20% of the total pyrite present, depending on the coal sample. The magnetite forms as an outer crust on the pyrite grains.

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Magnetite Applications and Uses | African Pegmatite

Magnetite contains iron in two oxidation states, ferric (Fe 3+) and ferrous (Fe 2+ ), which is unique amongst the oxides of iron. Its structure is an inverse spinel, with the oxide ions forming a face centred cubic lattice, with iron taking the space in the interstitial sites. Naturally occurring magnetite is mostly found as octahedral crystals.

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NIOSHTIC-2 Publications Search - 10003233 - Oxidation of Pyrite to ...

The primary purpose of the work included attempts to understand the processes wherein magnetic substances can be created from pyrite with the ultimate goal of aiding in the magnetic separation of pyrite, and hence sulfur from coal. This report presents a detailed description of the investigation. Publication Date 19830101 Document Type

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Mechanisms of Pyrite Oxidation to Non-slagging Species

A project was undertaken to characterize the oxidation of iron pyrite to the non-slagging species magnetite during pulverized coal combustion. The work was aimed at defining the pyrite transformations responsible for the higher slagging propensity of staged, low-NO x pulverized coal combustor burners.

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Oxidation of pyrite in an anoxic atmosphere - USGS

Pyrite (FeS2) inclusions in coal, when heated in an oxygen deficient atmosphere (approximately 1% oxygen), become coated with magnetic Fe3O4 due to oxidation. Most of the FeS2 can thus be removed from the coal by magnetic separation to reduce the sulphur concentration.

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