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pyrite oxidation process

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Pyrite oxidation in acidic medium: overall reaction pathway

Pyrite weathering, the main process leading to acid mine drainage,[2] results from a combination of oxidation and dissolution processes involving ferric ion and oxygen[3,4] andfrommicrobialactivity.[5] Additionally, pyrite is an ubiquitous component in the environment and should thus be considered as a reservoir of reductants for toxic oxidized ...

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(PDF) Pyrite Oxidation Mechanism by Oxygen in Aqueous …

2016-1-11 · A chemical picture of the pyrite oxidation process in the presence of oxygen and water was proposed in the present investigation. The reaction steps of the oxidation mechanism can be separated ...

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AMD: Basic chemistry

2011-3-28 · The fourth reaction is the oxidation of additional pyrite by ferric iron. The ferric iron is generated in the reactions described above. This is the cyclic and self propagating part of the overall reaction and takes place very rapidly and continues until either ferric iron or pyrite is depleted. Note that in this reaction, iron is the oxidizing ...

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Electrochemical study on Surface Oxidation of Natural ...

2019-7-7 · The overall surface oxidation process on pyrite occurred in the potential range of -0.450 V to 0.050 V vs. AgCl/Ag. The average ETN for pyrite oxidation was around 2 in sulfuric acid. The increasing of ferric ion was found to affect ETN markedly while the polarization current was raised, which indicate that the pyrite electrochemical oxidation ...

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Anaerobic pyrite oxidation in a naturally occurring pyrite ...

2019-3-13 · Pyrite oxidation is a worldwide problem affecting the mining, construction, and agricultural industries. Mitigation and rehabilitation cost runs into several billions of dollars (Wheel and Feasby 1991).Oxygen is consumed in pyritic sediments by two main microbial mediated processes: organic matter decomposition and pyrite oxidation.

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Pyrite Oxidation Kinetics

2018-2-19 · 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…

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Aqueous Pyrite Oxidation and the Consequent Formation …

The oxidation of pyrite in aqueous systems is a complex biogeochemical process involving several redox reactions and microbial catalysis. This paper reviews the kinetic data on pyrite oxidation, compares available data on the inorganic vs. microbial oxidative mechanisms and describes the occurrence of mineral products resulting from pyrite oxidation.

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Effect of temperature and illumination on pyrite oxidation ...

2000-7-4 · 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 most aqueous environments, the oxidant for the reaction is either dissolved molecular oxygen [reaction (1)] or dissolved ferric iron [reaction (2)].

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PYRITE OXIDATION UNDER CIRCUMNEUTRAL pH …

2012-9-26 · basic equations for pyrite oxidation, Eq. (2). was created by Nordstrom [3], who assumed the process to be an abiotic system, thus the oxidizer agent is the oxygen: o FeS ( s ) ( aq ) 2 O ( g ) SO ( aq ) Fe ( aq ) 2H ( aq ) 7 2 2 2 2 2 4 (2) The Fe2+ – released by pyrite oxidation – may be further oxidized (3) to Fe3+, decreasing the

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Inhibition of pyrite oxidation using PropS-SH/sepiolite ...

2020-10-27 · In this process, pyrite can be dissolved rapidly under the attack of oxidants such as dissolved O 2 (DO) and Fe 3+ (Li et al. 2016; Tabelin et al. 2017b). In particular, this oxidation process can be maintained and enhanced under the catalysis of oxidizing bacteria (especially acidophiles such as Thiobacillus ferrooxians).

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Mechanisms of arsenic-containing pyrite oxidation by ...

2017-11-15 · During the redox processes of arsenic-containing pyrites and arsenate, elemental S 0, SO 4 2− and goethite were formed as the main products with the adsorption of As(III,V), and As(III) was released due to the collapse of the crystal structure of pyrite and the oxidation of As(−I). Different redox mechanisms were achieved with pH increasing ...

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Environmental Problems Related to Pyrite Oxidation …

2008-10-29 · pyrite oxidation process within the waste dump. Geochemical analysis of samples taken from various depths in the dump showed that the pyrite oxidation formed acid mine drainage and toxic metal leaching. pH dropped to 3.5 and a peak concentration of sulphate equal to 349 mg/L was formed at depth 0.5 m. CO 3 2-

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Technical Note Pyrite oxidation by hydrogen peroxide in ...

2015-12-27 · concentration were examined. The oxidation process can be described by the heterogeneous kinetic model in which the surface decomposition reaction is the rate-determining step. An activation energy of 49kJ/mol for pyrite oxidation is estimated. It was found that the smaller the particle size or the higher the reaction

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The causes behind pyrite oxidation

2020-11-1 · 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.

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Probabilistic Prediction of Acid Mine Drainage Generation ...

Pyrite Oxidation Kinetics - How Fast does Pyrite Oxidize

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Pyrite Oxidation Kinetics

2018-2-19 · 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 …

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The mechanisms of pyrite oxidation and leaching: A ...

Pyrite is the earth''s most abundant sulfide mineral. Its frequent undesirable association with minerals of economic value such as sphalerite, chalcopyrite and galena, and precious metals such as gold necessitates costly separation processes such as leaching and flotation. Additionally pyrite oxidation is a major contributor to the ...

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(PDF) A Review on Pyrrhotite Oxidation

As it is the case for pyrite, an increase in temperature has an increasing effect on the oxidation of pyrrhotite and the process follows the Arrhenius behaviour. Both ferric iron and bacteria act ...

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Experimental Study of Pyrite Oxidation at 100 °C ...

The oxidation of pyrite is one of the near field processes of the chemical evolution of clay rock planned to host a deep geological radioactive waste repository during operation. Indeed, this process can lead to transitory acidic conditions in the medium (i.e., production of sulphuric acid, carbonic acid) which may influence the corrosion kinetics of the carbon steel components of …

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A review: Pyrite oxidation mechanisms and acid mine ...

2009-1-9 · 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 …

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Morphology dominated rapid oxidation of framboidal …

2021-2-9 · The pyrite oxidation process has been investigated extensively for decades, particularly the reaction kinetics and oxidation mechanism. Most previous studies mainly focused on powder samples, i.e. fracture surfaces, and ignored crystal facet effects (Zhu et al., 2018.

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The mechanisms of pyrite oxidation and leaching: A ...

2010-9-1 · Pyrite oxidation is however complex as it is a multi-step process with the possibility of both homogenous and heterogeneous processes. "Purely chemical" reactions do not form a major part of most natural processes, including corrosion, photosynthesis and biological respiration [90] .

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Oxidation of Pyrite

2021-8-12 · However, pyrite is quite easy to distinguish from gold, i.e., pyrite is much lighter, but harder than gold and cannot be scratched with a fingernail or knife (TMM, 2014). In addition, pyrite will tarnish when exposed to acid, whereas gold is nonreactive (IGS, 2011). 3.2.1.2 Oxidation Process

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(PDF) Pyrite Oxidation Mechanism by Oxygen in Aqueous …

2016-1-11 · A chemical picture of the pyrite oxidation process in the presence of oxygen and water was proposed in the present investigation. The reaction steps of the oxidation …

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geochemistry

2021-8-3 · Oxidation and dissolution are not the same processes, but they are related when discussing the breakdown of pyrite in near surface environments. Dissolution is a process(*1) in which the chemical components of a solid become part of a liquid, in the liquid state. For example, take fresh water and salt. Now dissolve the salt in the fresh water.