Coal enhancement process and equipment: : Nankee et al. 209/11: 4496533: Process for purifying graphite: ... Usually a high degree of dissemination of the pyrite in the coal makes the pyrite removal more difficult and also the incorporation of chalcopyrite into the pyrite may change the surface properties of the pyrite in terms of its ...

Magnetic enhancement of pyrite in coal 64 Magnetic seeding 64 Thermal treatment 65 Oxidation and reduction 67 Dielectric heating 69 Iron carbonyl treatment 70 Principles of magnetic separation 70 EXPERIMENTAL INVESTIGATION 72 Equipment and Apparatus 72 …

Pyrite, discarded coal, and overburden rock and soil sit in waste piles and oxidation occurs. Movement of water through the exposed coal and waste piles mobilizes the hydrogen created in the oxidation reaction. As a result, the drainage areas from the coal mines become very acidic. In these wet, acidic, environments acidophiles, acid loving ...

Pyrite's metallic luster and pale brass-yellow hue give it a superficial resemblance to gold, hence the well-known nickname of fool's gold.The color has also led to the nicknames brass, brazzle, and Brazil, primarily used to refer to pyrite found in coal.. The name pyrite is derived from the Greek πυρίτης λίθος (pyritēs lithos), "stone or mineral which strikes fire", in turn from ...

examines mechanisms and enhancement of pyrite and ash suppression and Part B provides engineering evaluation and scale up, via three major tasks: lB. Develop a pyrite suppression screening test lIB. Define engineering scale bioreactor process parameters for micro­ ... suppression for both a mineral and coal derived pyrite.

CONCLUSIONS The magnetic desulphurisation of the pyrite content of coal by microwave irradiation in the presence of 300 g/l NaOH is due to the formation of small amounts of a strongly magnetic phase, probably pyrrhotite or magnetite and the loss of sulphur as a dissolved species - both sulphide and sulphate. Magnetic enhancement of pyrite 361 ...

Study of magnetic enhancement of coal-derived pyrite by pyrolysis May 2011 Zhongguo Kuangye Daxue Xuebao/Journal of China University of Mining and Technology 40(3):459-463

Bioleaching is the mobilization of metal cations from insoluble ores by microorganisms. Biofilms can enhance this process. Since Sulfobacillus often appears in leaching heaps or reactors, this genus has aroused attention. In this study, biofilm formation and subsequent pyrite dissolution by the Gram-positive, moderately thermophilic acidophile Sulfobacillus thermosulfidooxidans were investigated.

The selective magnetic enhancement of pyrite in coal by dielectric heating was investigated fundamentally and experimentally. Fundamental treatment consisted by the measurement of the dielectric properties, at frequencies ranging from 1 HMz to 11.7 GHz, of a …

Grindability of Pyrite and Coal-An Aid in Separation. Figure 7 demonstrates the behavior of coal and pyritic material when subjected to two types of grinding action. The materials used in this test had been previously sized to 16 by 30 mesh, then cleaned by the float-sink separation (the coal floated at 1.6 sp gr, and the pyritic materials sank ...

@article{osti_6828787, title = {The chemical enhancement of the triboelectric separation of coal from pyrite and ash: A novel approach for electrostatic separation of mineral matter from coal}, author = {Gustafson, R. M. and DiMare, S. and Sabatini, J.}, abstractNote = {Arthur D. Little, Inc., under contract to the US DOE Pittsburgh Energy Technology Center, has developed a triboelectric ...

Enhancement of ash & pyrite separation from coal by pretreatmnt w/ ultrasound. USP # 4,391,608 ~ (CA 99:90944) ~ Ultrasonic Beneficiation of Coal ~ Slurried coal is deashed & desulfurized by treatment w/ ultrasound (20 KHz @ 0.7 W/cm2/30 min) followed by separation & washing.

Finely divided coal or coal derivatives, containing pyrite, are reacted with sulfurous acid (the oxidizing agent); if desired, HCl may also be used to improve the reaction efficiency to remove pyritic sulfur from coal as shown by the following equations: Primary: Oxidation - reduction 4 FeS2 (pyrite) +3SO2 + 12 HCl -> 4 FeCl3 + 11S + 6 H2O Secondary: Oxidation - reduction 4 FeCl3 + FeS2 ...

During SO 2 removal from flue gas by coal slurry scrubbing, coal pyrite sulfur can be simultaneously reduced. But satisfactory coal pyrite conversion cannot be achieved under normal scrubbing conditions. In the present work, aluminum oxide and aluminum sulfate were tested as additives to enhance the leaching of coal pyrite during SO 2 removal in a bubbling reactor.

Abstract The early diagenetic characteristics of pyrite formation processes in a Miocene freshwater sequence of mixed sediments (coal fragments in clays, sandstones or shales) alternating with continuous brown coal layers was investigated. Based on abundant minerals, the following main sedimentary environments were distinguished: the illite-montmorillonitic (I-M), calcitic (Ct) and coal ...

Enhancement of microbial removal of pyritic sulfur from coal using concentrated cell suspension of T. ferrooxidans and an external carbon dioxide supply. ... Mechanism of bacterial pyrite oxidation. Silverman MP. J Bacteriol, (4):1046-1051 1967

Five strategies, including adjusting initial pH, supplementing an extra energy source or ferric ions, as well as exchanging exhausted medium with fresh medium, were tested for enhancement of its biofilm formation. The results show that regularly exchanging exhausted medium leads to a continuous biofilm development on pyrite.

Iron pyrite (iron(ii) disulfide, FeS 2) is a naturally occurring sulfide mineral, and is the most common example.It is found naturally in quartz seams and alongside coal deposits. In its pure form, it has a metallic lustre that gives it a superficial appearance to gold - hence pyrite is …

The prediction model of electromagnetic parameters during the process of microwave dielectric enhancement of fine coal is established by using the neural network method. ... . 16,17 The magnetic properties of pyrite can be improved by heating treatment. 18 Compared with coal, pyrite can be heated more rapidly due to its higher dielectric ...

Enhancement of Magnetism of Pyrite. As seen in table 4, coals are slightly diamagnetic, that is, when placed in an inhomogeneous magnetic field, they tend to move toward the weaker regions of the field. Pyrite, on the other hand, is slightly paramagnetic and moves toward the stronger regions of the field. ... Selective Heating of Pyrite in Coal ...

Kinetics of Pyrite Oxidation The acidity of coal-mine drainage is caused primarily by the oxidation of the mineral pyrite (FeS 2), which is found in coal, coal overburden, and mine waste piles.Pyrite oxidation and the consequent generation of sulfuric acid have long been recognized as major contributors to acid rock drainage, yet pyrite reactivity remains poorly understood.

Pyrite and Coal Mining Sulfur occurs in coal in three different forms: 1) organic sulfur, 2) sulfate minerals, and 3) sulfide minerals (mostly pyrite with minor amounts of marcasite). When the coal is burned, these forms of sulfur are converted into sulfur dioxide gas and contribute to air pollution and acid rain unless they are removed from ...

Enhancement of flaky graphite cleaning by ultrasonic treatment; Abstract. In this study, the aim is to simplify the graphite cleaning process. In order to achieve flotation for graphite effectively, ultrasonic treatment was used as a pre-treatment technique. ... treatment can promote the dissociation between coal and pyrite and increase the ...

A systematic in situ electron paramagnetic resonance (EPR) study of the effects of minerals and iron on the formation of free radicals during coal pyrolysis has been carried out. The results show that when pyrite is added to Pittsburgh No. 8 raw coal, an enhancement in the radical yield is observed in the presence of other inherent minerals. An attempt has been made to isolate the specific ...

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 …

Naturally occurring pyrite commonly contains minor substituted metals and metalloids (As, Se, Hg, Cu, Ni, etc.) that can be released to the environment as a result of its weathering. Arsenic, often the most abundant minor constituent in pyrite, is a sensitive monitor of progressive pyrite oxidation in coal. To test the effect of pyrite composition and environmental parameters on the rate and ...

@article{osti_10120574, title = {The chemical enhancement of the triboelectric separation of coal from pyrite and ash: A novel approach for electrostatic separation of mineral matter from coal. Final report}, author = {Gustafson, R M and DiMare, S and Sabatini, J}, abstractNote = {Arthur D. Little, Inc., under contract to the US DOE Pittsburgh Energy Technology Center, has developed a ...

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 mineral pyrite, or iron pyrite, is an iron sulfide with the formula FeS 2. This mineral's metallic luster and pale brass-yellow hue have earned it the nickname fool's gold because of its resemblance to gold. The color has also led to the nicknames brass, brazzle and Brazil, primarily used to refer to pyrite found in coal.

ABSTRACT An oxidized coal surface is more negatively charged and hydrophilic than that of fresh coal because of the introduction of polar oxygen functional groups. During flotation, the decreased attractive hydrophobic force between bubbles and coal particles and the increased repulsive electrostatic force result in a low recovery for oxidized coal.

Mercury thermospecies in pyrite It was found out that signi˜cant part of mercury in productive coal horizons is accumulated in sul˜des, mainly in pyrite, FeS 2 [1, 2]. Therefore, it is interesting to compare the mercury thermospectra of pyrite and pyrite-bearing coals (Fig. 4). Fig. 4. Thermospectra of pyrites and coal.