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01-05-1984 To obtain a suitable build-up of Fe304 from pyrite in coal, therefore, the coal should be Oxidation of pyrite in coal to magnetite: A. N. Thorpe et al. heated to a relatively low temperature (390-408) at a low partial pressure of air (1.6-2.4 kPa).
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.
A method for increasing the magnetization of pyrite-containing pulverized coal comprises heating the coal in an atmosphere of inert gas, desirably nitrogen, containing 3 to 60 torr, preferably 12 to 16 torr, partial pressure of air to a temperature in the range 390° to 455° C., desirably 400° to 410° C., for a time sufficient, preferably 2 minutes to 2 hours, for converting enough pyrite to magnetite to allow separation of at least 50% by weight of the pyrite from the coal
micromill steel oxidation of pyrite in coal to magnetite From pyrite heating in n , whereas the residue when heated in co denotes the presence of magnetite it was proposed that co dissociates in co and o after heating to c, so transformation in co involved partial oxidation to magnetite, in accordance with equation fes co g fe o fe o cos g so g
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.
OSTI.GOV Patent: Method for oxidation of pyrite in coal to magnetite and low field magnetic separation
Arthur N. Thorpe, Frank E. Senftle, Corrine C. Alexander, Frank T. Dulong, Oxidation of pyrite in coal to magnetite, Fuel, 10.1016/0016-2361(84)90163-7, ... Periodic thermal instability during the isothermal oxidation of pyrite, Metallurgical Transactions B, 10.1007/BF02654146, 12, 4, ...
Pyrite oxidation has been studied extensively, in the past, because of its importance in sulfide mineral separations by flotation, in the generation of acid in mine waters and in leaching of pyrite. The oxidation of pyrite also plays key role in supergene alteration of ore deposits, the formation of acid sulfate soils, etc. Pyrite oxidation is generally recognized as a complicated process ...
28-09-2015 Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion. The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and released heat etc., were investigated in this study. Coal samples with different pyrite
15-01-2004 Although pyrite mineral is a good microwave absorber and can be easily converted to more magnetic minerals such as pyrrhotite by heating, pyrite in coal could not be heated enough and increase in magnetic property of pyrite in coal by microwave heating at 850 W and 2.45 GHz was not sufficient to enhance the removal of considerable amount of pyrite by
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. With such burners, coal is injected into a reducing
Abstract. This report describes research on coal combustion processes and pyrite oxidation processes. Work focuses on the oxidation of iron pyrite to form the non-slagging magnetite.
Arthur N. Thorpe, Frank E. Senftle, Corrine C. Alexander, Frank T. Dulong, Oxidation of pyrite in coal to magnetite, Fuel, 10.1016/0016-2361(84)90163-7, ... Periodic thermal instability during the isothermal oxidation of pyrite, Metallurgical Transactions B, 10.1007/BF02654146, 12, 4, ...
pyrite oxidation. Task 4: Carbon Matrix Kinetics Effects Objective: to perform combustion tests to characterize the effects of carbon matrix oxidation kinetics on the overall oxidation rate of pyrite inclusions. Deliverables: A procedure for performing chemical analysis of the solid residue of the combustion of pyrite- laden synthetic coal.
Oxidation of Pyrite Oxidation of Pyrite SCHOENLAUB, ROBERT A. 1969-01-01 00:00:00 OXYGEN PRESSURE O 1 where i t transforms to cuprous CU6MO4016, which melts congruently a t 895°C. CuzMoOsmelts peritectically a t 880°C. The MoO3-CuMoO4 eutectic occurs near 30 mol% CuO a t 705°C.
Pyrite oxidation has been studied extensively, in the past, because of its importance in sulfide mineral separations by flotation, in the generation of acid in mine waters and in leaching of pyrite. The oxidation of pyrite also plays key role in supergene alteration of ore deposits, the formation of acid sulfate soils, etc. Pyrite oxidation is generally recognized as a complicated process ...
08-11-2015 Pyrite is also an undesired inorganic constituent present in coal. Flotation techniques have been developed to separate pyrite ... Pearson19 showed that, in the pyrite oxidation process, a minimum of 7 electron-transfer steps are necessary to describe completely the oxidation on the pyrite surface.
Entrainment of Magnetite by Coal During Dense-Medium Beneficiation of Coal. January 1990; Coal Preparation 8(3-4):195-203; DOI: 10.1080/07349349008905185
Change in pH as a function of the amount of pyrite oxidized under five scenarios: (i) Pyrite oxidizes to an acid ferrous sulfate solution without any further oxidation (solid green line); (ii) pyrite oxidizes, and the resultant ferrous sulfate solution is allowed to oxidize, but no precipitation is allowed (upper red line); (iii) pyrite oxidizes, the ferrous sulfate solution oxidizes and ...
Pyrite is the most abundant iron−sulfur mineral in sediments. Over geological times, its burial controlled oxygen levels in the atmosphere and sulfate concentrations in seawater. However, the mechanism of pyrite formation in sediments is still being debated. We show that lithotrophic microorganisms can mediate the transformation of FeS and H2S to FeS2 at ambient
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. With such burners, coal is injected into a reducing environment.
Pyrite oxidation has been studied extensively, in the past, because of its importance in sulfide mineral separations by flotation, in the generation of acid in mine waters and in leaching of pyrite. The oxidation of pyrite also plays key role in supergene alteration of ore deposits, the formation of acid sulfate soils, etc. Pyrite oxidation is generally recognized as a complicated process ...
pyrite oxidation. Task 4: Carbon Matrix Kinetics Effects Objective: to perform combustion tests to characterize the effects of carbon matrix oxidation kinetics on the overall oxidation rate of pyrite inclusions. Deliverables: A procedure for performing chemical analysis of the solid residue of the combustion of pyrite- laden synthetic coal.
Pyrite has a significant effect on the spontaneous combustion of coal. The presence of pyrite can change the propensity of coal towards spontaneous combustion. The influences of various pyrite contents on the parameters of spontaneous combustion, such as index gases, temperature and released heat etc., were investigated in this study. Coal Cited by:
08-11-2015 Pyrite is also an undesired inorganic constituent present in coal. Flotation techniques have been developed to separate pyrite ... Pearson19 showed that, in the pyrite oxidation process, a minimum of 7 electron-transfer steps are necessary to describe completely the oxidation on the pyrite
The article was addressed to the transformation of excluded pyrite during O2/CO2 combustion of pulverized coal. Raw pyrite mineral was added to a pulverized coal sample, which was density fractionated to remove the excluded minerals, to simulate the excluded pyrite present in coal. The mixed sample was burned in a drop tube furnace in O2/CO2 and O2/N2 conditions to generate the residue
Fine-grained pyrite in some Chinese coals has been investigated, with analysis by optical microscopy and a scanning electron microscope equipped with energy dispersive X-ray spectrometer illustrating that the interaction between mineral and organic matters results in the irregular pyrite crystal present in coal.
Pyrite is the most abundant iron−sulfur mineral in sediments. Over geological times, its burial controlled oxygen levels in the atmosphere and sulfate concentrations in seawater. However, the mechanism of pyrite formation in sediments is still being debated. We show that lithotrophic microorganisms can mediate the transformation of FeS and H2S to FeS2 at ambient temperature if metabolically ...
Pyrite is a key mineral in the global biogeochemical cycles of sulfur and iron, yet its anaerobic microbial oxidation has eluded geochemists and microbiologists for decades. Recent reports indicated that anaerobic oxidation of pyrite is occurring, but the mechanism remains unclear. Here, we provide evidence for the capability of Thiobacillus denitrificans to anaerobically oxidize a putatively ...
The oxidation fraction or the degree of oxidation orf the magnetite pellets exposed to different isothermal temperatures and different O 2 content in oxidizing gas with respect to time is shown in Fig. 2. The oxidation continuously increases with time under the giventhermal and gaseous atmosphere.
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