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Pyrite coal oxidation

  • Environmental Problems Related to Pyrite Oxidation from an

    Key words: pyrite oxidation, acid mine drainage, coal washing plant, coal waste dump, Alborz-Sharghi, heavy metals Introduction Iran is the main coal producer in the Middle East. Coal mines have made a considerable contribution to Iranian mining industry and the national economy. Alborz Sharghi is a major coal company in

  • Clay and pyrite transformations during ignition of

    Oxidation of pyrite leads to coating of cenospheres by condensed magnetite and the emission of sulphur dioxide in the flue gases. Type Research Article. Chemical composition and size of particles in emissions of a coal-fired power plant with flue gas desulfurization. Journal of

  • Effects of pyrite on the spontaneous combustion of coal

    release during coal oxidation for various pyrite contents. The results indicate that pyrite can nonlinearly accelerate the process of spontaneous combustion. The coal sample with a pyrite content of 5 % has the largest CO release rate and oxygen adsorption as well. However, the coal sample with a pyrite content of 7 % has the largest rate of

  • Surface Oxidation of Pyrite as a Function of pH

    Aug 29, 1998· The oxidation of pyrite was studied in batch experiments over a large range of pH (2.512), with trace oxygen. Surface analysis of the samples was performed using X-ray photoelectron spectroscopy (XPS).

  • Pyrite Oxidation Mechanism by Oxygen in Aqueous Medium

    Nov 08, 2015· 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. Furthermore, it is well-known that different bacteria can catalyze the pyrite oxidation at a much rapid rate, making its mechanism even more complex.20

  • Effects of pyrite on the spontaneous combustion of coal

    Sep 28, 2015· The pyrite in coals can absorb oxygen and release heat, causing an inflation of coal and therefore accelerating the oxidation process. Besides, sulphuric acid (H 2 SO 4) will be produced during the oxidation of pyrite.

  • Evaluation of factors affecting pyrite oxidation and

    Evaluation of factors affecting pyrite oxidation and subsequent pollutant generation in backfilled open cut coal mines R. N. Singh Professor of Mining Engineering, Faculty of Engineering, University of Wollongong Northfields Avenue, Wollongong, NSW 2522, Australia.

  • A review: Pyrite oxidation mechanisms and acid mine

    Jan 09, 2009· Abstract. Sulfide oxidation, part of sulfur's biotic/abiotic cycle, is an important natural phenomenon. However, because of the sulfide's association with metallic ores and fossil fuels in the form of pyrite (FeS 2) and the world's increasing demand for metals and fossil fuels, sulfide oxidation in nature is in some state of perturbation.This perturbation, which results from land disturbances

  • Probabilistic Prediction of Acid Mine Drainage Generation

    the pyrite oxidation process are deterministic. Hence, in this work, we evaluated the risk of the pyrite oxidation generation within a coal waste pile applying a probabilistic method. 2.1. Materials and Methods 2.1. Pile description The Alborz Sharghi coal washing plant is located in the Semnan Province, NE of Iran

  • University of Wollongong Research Online

    results clearly demonstrate the accelerating effect of pyrite oxidation on coal self-heating. As the pyrite content increases, the self-heating rate of the coal also increases. This is shown in Figure 3 where the time taken to reach thermal runaway (100 C) is non-linearly related to the pyrite content of the coal. In

  • Oxidation of Pyrite - LAUB - 1969 - Journal of the

    The decomposition of pyrite was investigated in a thermobalance. In neutral or reducing gases it decomposes between 550° and 700°C to volatile sulfur and ferrous sulfide. 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, 63, 5, (662

  • Pyrite Mineral Uses and Properties

    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

  • Bacterial Oxidation of Pyritic Materials in Coal

    OXIDATION OF PYRITIC MATERIALS IN COAL cells of F. ferrooxidans accelerated the release of acid- soluble iron from the pyrite. When comparable samples, such as the two pyrite concentrat"es (samples 29 and 30), were ground to the same mesh size, the rate of oxygen uptake was pro- portional to the pyrite content of the sample. The data in Fig. 1 show that the oxygen uptake rate with

  • (PDF) Adenine oxidation by pyrite-generated hydroxyl

    Adenine oxidation by pyrite-generated hydroxyl radicals. Martin Schoonen. Related Papers. Role of pyrite in formation of hydroxyl radicals in coal: possible implications for human health. By Richard Laffers. Evaluating the use of 3'-(p-Aminophenyl) fluorescein for determining the formation of highly reactive oxygen species in particle

  • Analysis of surface modification on coal pyrite

    The distribution of coal pyrite in coal is relatively complex, and it is therefore impossible to reach ideal separation efficiency by means of a common flotation technique. The key factor affecting the separation between coal and pyrite is that the hydrophilic surface of pyrite became hydrophobic after oxidation. The hydrophobic oxidation products

  • The effect of environment, oxidation and dissolved metal

    Oxidation of pyrite also leads to the generation of various soluble inorganics that can adsorb on the coal surface and modify its wettability and floatability (Berkowitz, 1989).

  • Pyrite oxidation - USGS

    Jan 08, 2001· Working with tailings on gold mines and discard dumps on coal mines one of the problems encountered is pyrite oxidation.

  • Pyrite oxidation in aqueous ferric chloride - King - 1977

    The rate of pyrite oxidation in aqueous ferric chloride was determined for two distinct solid particle systems: industrial grade pyrite and coal particles containing pyrite. The oxidation rate for th

  • (PDF) Review on the Bio-oxidation of Pyrite: Implications

    Mar 27, 2021· Bio-oxidation of Pyrite is an important technology, which mainly means the surface Oxidation and/or the oxidative dissolution of Pyrite in the presence of microorganisms.

  • Pyrite Oxidation Drives Exceptionally High Weathering

    Jul 15, 2018· These coal mining activities will result in the liberation and oxidation of pyrite minerals, enhanced potential for strong acid weathering, the production of dissolved salts, and the release of geologically bound C. Unlocking geologically sequestered pyrite

  • OXIDATION OF COAL AND COAL PYRITE MECHANISMS

    Oxidation of Coal and Coal Pyrite: FM.Doyle. Univ. California at Berkeley 2/28/95 b. Oxidation Treatments Upper Freeport bituminous coal from the Troutville #!2 Mine, Clearfield County, Pennsylvania was oxidized thermally in air by heating the coal in a Precision mechanical convection oven at

  • Surface Oxidation of Pyrite as a Function of pH

    Aug 29, 1998· Pyrite, the most abundant metal sulfide at the surface of Earth, plays a key role in many processes such as acid mine drainage, redox cycling of metals at oxic-anoxic boundaries of lake bottom, and degradation of pollutants. The oxidation of pyrite was studied in batch experiments over a large range of pH (2.512), with trace oxygen. Surface analysis of the samples was performed using X-ray

  • Adenine oxidation by pyrite-generated hydroxyl radicals

    Apr 26, 2010· Pyrite (FeS 2), the most common metal sulfide mineral associated with coal and metal mine waste, has been shown to generate hydrogen peroxide (H 2 O 2) [1,2] and hydroxyl radicals ( OH) [3,4] when placed in water.In the presence of dissolved molecular oxygen, ferrous iron associated with pyrite can form superoxide anion (O 2 ) - (eq. 1), which reacts with ferrous iron to form H 2 O 2 (eq

  • Pyrite oxidation - USGS

    Jan 08, 2001· Working with tailings on gold mines and discard dumps on coal mines one of the problems encountered is pyrite oxidation. I'd like to gather some example files which deal with kinetic pyrite oxidation (in PHREEQC2) in two principal scenarios: - pyrite oxidation under unsaturated conditions with oxygen flow/diffusion (e.g. in discard heaps

  • Predicting pyrite oxidation and multi-component reactive

    Abstract. In this paper, pyrite oxidation process resulted from an abandoned coal waste pile in northeastern Iran was evaluated by a combination of three-dimensional (3D) geo-electrical data inversion and two-dimensional (2D) numerical modeling of long-term pyrite oxidation and multi-component reactive transportation of the oxidation products.

  • asilentreverie: Pyrite Oxidation Chemistry-Acid Mine Drainage

    Dec 12, 2005· Pyrite is present in coal seams and the rock layers overlying coal seams and the formation of acid mine drainage arises in surface mining, in which the overlying rocks are broken and removed to the extracted the coal. Pyrite oxidation by bacteria is classified into either direct metabolic reactions which requires physical contact between

  • Pyrite Oxidation and Its Control - 1st Edition - V. P

    May 04, 1995· Pyrite Oxidation and its Control is the single available text on the market that presents the latest findings on pyrite oxidation and acid mine drainage (AMD). This new information is an indispensable reference for generating new concepts and technologies for controlling pyrite oxidation.This book focuses on pyrite oxidation theory, experimental findings on oxidation

  • Oxidation of pyrite in coal to magnetite - ScienceDirect

    May 01, 1984· (Keywords: coal; oxidation; pyrite) High-gradient magnetic separation of pyritic iron and sulphur from water slurries of pulverized coal is not uniformly successful for all coals1"5. Because pyrite is only slightly magnetic, separation has been enhanced by heating the coal to >400 in an inert or reducing atmosphere to convert part of the pyrite

  • Pyrite Oxidation Kinetics - How Fast does Pyrite Oxidize

    Feb 19, 2018· 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 which includes several oxidation/reduction reactions, complexation and hydrolysis reactions, and solid/solution equilibria.

  • Analysis of surface modification on coal pyrite

    Coal desulphurization by flotation is often difficult due to the surface oxidation of coal pyrite. Scanning electron microscope (SEM) and X-ray diffraction (XRD) were adopted to obtain detailed

  • Pyrite oxidation in coal bearing strata:: controls on in

    Jun 26, 2012· Pyrite oxidation in coal-bearing strata is recognised as the main precursor to Acidic Mine Drainage (AMD) generation. Predicting AMD quality and quantity for remediation, or proposed extraction, requires assessment of interactions between oxidising fluids and pyrite, and between oxidation products and groundwater. Current predictive methods and models rarely account for individual mineral

  • Pyrite Oxidation Drives Exceptionally High Weathering

    Jul 15, 2018· These coal mining activities will result in the liberation and oxidation of pyrite minerals, enhanced potential for strong acid weathering, the production of dissolved salts, and the release of geologically bound C. Unlocking geologically sequestered pyrite has important implications for global biogeochemical cycles of S, C, Ca, and Mg, whether

  • Effect of temperature and illumination on pyrite oxidation

    Jul 04, 2000· Pyrite oxidation is an important process in the geochemical cycles of iron and sulfur.[1, 2] In aerobic near-surface aqueous environments, pyrite is thermodynamically unstable and oxidizes.In most aqueous environments, the oxidant for the reaction is either dissolved molecular oxygen [reaction (1)] or dissolved ferric iron [reaction (2)].

  • Oxidation of pyrite in coal to magnetite - USGS

    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. The magnetite forms as an outer crust on the pyrite grains.

  • Method for oxidation of pyrite in coal to magnetite and

    If this oxidation model of pyrite in coal is reasonably accurate, and if the fraction of pyrite converted to Fe 3 O 4 is essentially the same from sample to sample, then by heating different coals under constant conditions of temperature and air pressure, the specific magnetization should be approximately proportional to the total pyritic

  • Oxidation of coal and coal pyrite mechanisms and influence

    Jan 01, 1992· Abstract The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes.

  • Oxygen transport and pyrite oxidation in unsaturated coal

    An understanding of the mechanisms of oxygen (02) transport in unsaturated mine spoil is necessary to design and implement effective measures to exclude 02 from pyritic materials and to control the formation of acidic mine drainage. Partial pressure of oxygen (Po2) in pore gas, chemistry of pore water, and temperature were measured at different depths in unsaturated spoil at two reclaimed

  • Frequency Distribution of the pH of Coal-Mine Drainage in

    presence of calcareous minerals; acid produced by pyrite oxidation is neutralized. The pH values in the acidic mode result from pyrite oxidation and imply a deficiency of calcareous minerals and the absence of carbonate buffering. The oxidation of only a small quantity of pyrite can acidify pure water (0.012 g·L-1 FeS 2 produces pH~4 and 20 mg

  • amrclearinghouse :::AMD Basics - PYRITE REACTIONS:::

    The mineral pyrite (FeS 2) and other sulfur containing minerals are common. Also common is the occurrence of these minerals in the geologic strata in the vicinity of coal seams. Mining coal inevitably involves exposing these pyritic materials to oxygen and water. In deep mines, these materials are exposed in the voids created by the mining process.

  • The causes behind pyrite oxidation - and acid mine

    Nov 01, 2020· Pyrite oxidation, which can lead to acid mine drainage, is a concern for miners all across the globe. However, little is known about the processes that cause this phenomenon. To investigate the

  • Oxidation of coal and coal pyrite mechanisms and influence

    Mar 01, 1996· The objective of this research is to develop a mechanistic understanding of the oxidation of coal and coal pyrite, and to correlate the intrinsic physical and chemical properties of these minerals, along with changes resulting from oxidation, with those surface properties that influence the behavior in physical cleaning processes. The action of coal and pyrite as reducing agents and as waste

  • Pyrite oxidation in aqueous ferric chloride - King - 1977

    The oxidation rate of pyrite in coal smaller than 325 mesh was much greater than in larger coal particles. The effect of temperature (80° to 100°C) on the oxidation of pyrite in coal was not significant, nor was the effect of pretreatment with 0.1N hydrochloric acid.

  • MECHANISMS OF PYRITE OXIDATION TO NON-SLAGGING

    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

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