pyrite mineral oxidation

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.

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Pyrite - Wikipedia

From the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite is probably best described as Fe S2 . This formalism recognizes that the sulfur atoms in pyrite occur in pairs with clear S–S bonds. These persulfide units can be viewed as derived from hydrogen disulfide, H2S2. Thus pyrite would be more descriptively called iron persulfide, not iron disulfide. In contrast, molybdenite, MoS2, features isolated sulfide (S ) centers and the oxidation state of molybdenu

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Pyrite Oxidation Kinetics - How Fast does Pyrite Oxidize

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 ...

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Pyrite oxidation: a state-of-the-art assessment of the ...

Mar 01, 2003 · It is now clear that the cathodic reaction is the rate-determining step for sulfide mineral oxidation (e.g., Brown and Jurinak, 1989). Williamson and Rimstidt (1994) showed that the pyrite oxidation rate depends on the concentration of Fe 3+ or O 2 (Fig. 2, Fig. 3). Because the oxidant is involved in the activated complex, we can deduce that electron transfer from the sulfide to the oxidant ...

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Aqueous Pyrite Oxidation and the Consequent Formation of ...

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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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

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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.

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Aqueous Pyrite Oxidation and the Consequent Formation of ...

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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Pyrite Oxidation Mechanism by Oxygen in Aqueous Medium ...

The mechanism of the initial steps of pyrite (100) surface oxidation was investigated in detail by means of density functional theory/plane-wave calculations. Pyrite oxidation is related to many environmental and technological issues, and its mechanism has not been completely understood. A chemical picture of the pyrite oxidation process in the presence of oxygen and water was proposed in the ...

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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

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Experimental Study of Pyrite Oxidation at pH 6-9 and 30°C ...

Pyrite oxidation was carried out under conditions of constant pH, pt^ and temperature in a thermostadted glass reaction vessel, with a magnetic stirrer

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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 ...

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

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 mechanisms, as well as ...

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Pyrite oxidation under initially neutral pH conditions

5 the development of an acidic nanoenvironment between the bacteria and the mineral surface where Fe3+-driven pyrite oxidation took place. Hydrogen peroxide (H2O2) is a much more aggressive oxidant than molecular oxy-gen (Rush et al., 1985; King, 1998). Unlike Fe3+-driven pyrite oxidation, the H 2O2-

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Anaerobic pyrite oxidation in a naturally occurring pyrite ...

Mar 13, 2019 · Pyrite undergoes oxidation when exposed to aqueous oxygen to produce acidic leachate with high concentrations of H+, SO42−, and Fe3+. The oxidation mechanism is currently ascribed to contact between the mineral and aqueous oxygen. Consequently, management of acidic leachate from acid sulfate soils and acid mine drainage is focused on the prevention of contact between the

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Morphology dominated rapid oxidation of framboidal pyrite ...

Feb 09, 2021 · He, H. (2018) Surface structure-dependent pyrite oxidation in relatively dry and moist air: Implications for the reaction mechanism and sulfur evolution. Geochimica et Cosmochimica Acta 228, 259–274.), which may have hindered the accurate determination of the pyrite oxidation mechanism.

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What is Pyrite? Why is pyrite a problem? | test ...

Pyrite or Iron Pyrite (FeS2) is a very common mineral that is present in many sedimentary rocks as framboidal crystals. Subject to certain conditions, pyrite is problematic in confined construction, such as under floor filling and bridge embankments. This is due to a

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Inhibition of pyrite oxidation by surface coating: a long ...

Keywords Sulfide mineral Pyrite oxidation Surface coating Acid mine drainage Introduction Pyrite (FeS 2) is the most abundant metal sulfide at the earth’s crust. Pyrite is readily oxidizable by O 2 and water (Singer and Stumm 1970; Craig and Vokes 1993). The overall reactions are initiated by the oxidation of sulfide minerals by ...

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Pyrite formation from FeS and H2S is mediated through ...

Apr 02, 2019 · 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

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Minerals | Free Full-Text | Experimental Study of Pyrite ...

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 some ...

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Pyrite oxidation mechanism in aqueous medium - Feng - 2019 ...

Jan 31, 2019 · The mineral pyrite is considered the most common form of the sulfide minerals. Its oxidation is a very important process in nature, which involves in the redox recycling of iron. However, because of the growing need for the industrial production, sulfide oxidation produces more and more acid mine (or rock) drainage.

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Pyrite oxidation under initially neutral pH conditions

5 the development of an acidic nanoenvironment between the bacteria and the mineral surface where Fe3+-driven pyrite oxidation took place. Hydrogen peroxide (H2O2) is a much more aggressive oxidant than molecular oxy-gen (Rush et al., 1985; King, 1998). Unlike Fe3+-driven pyrite oxidation, the H 2O2-

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Experimental Study of Pyrite Oxidation at pH 6-9 and 30°C ...

Pyrite oxidation was carried out under conditions of constant pH, pt^ and temperature in a thermostadted glass reaction vessel, with a magnetic stirrer

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

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 mechanisms, as well as ...

Read More+

Pyrite oxidation: A state-of-the-art assessment of the ...

Pyrite oxidation is described as an electrochemical reaction with the reaction at the mineral surface occurring between iron (Fe) in the pyrite and an oxidant, typically ferric iron [8,9]; sulphur ...

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Anaerobic pyrite oxidation in a naturally occurring pyrite ...

Mar 13, 2019 · Pyrite undergoes oxidation when exposed to aqueous oxygen to produce acidic leachate with high concentrations of H+, SO42−, and Fe3+. The oxidation mechanism is currently ascribed to contact between the mineral and aqueous oxygen. Consequently, management of acidic leachate from acid sulfate soils and acid mine drainage is focused on the prevention of contact between the

Read More+

Pyrite formation from FeS and H2S is mediated through ...

Apr 02, 2019 · 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

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Pyrite: Mineral information, data and localities.

Pyrite Group. The isometric (cubic) polymorph of orthorhombic marcasite.Compare UM1997-43-S:Fe. Pyrite is a very common mineral (also one of the most common natural sulfides, and the most common disulfide), found in a wide variety of geological formations from sedimentary deposits to hydrothermal veins and as a constituent of metamorphic rocks.The brassy-yellow metallic colour of pyrite has in ...

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Pyrite

Formal oxidation states for pyrite, marcasite, and arsenopyrite. From the perspective of classical inorganic chemistry, which assigns formal oxidation states to each atom, pyrite is probably best described as Fe 2+ S 2 2-. This formalism recognizes that the sulfur atoms in pyrite occur in pairs with clear S-S bonds.

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Inhibition of pyrite oxidation by surface coating: a long ...

Keywords Sulfide mineral Pyrite oxidation Surface coating Acid mine drainage Introduction Pyrite (FeS 2) is the most abundant metal sulfide at the earth’s crust. Pyrite is readily oxidizable by O 2 and water (Singer and Stumm 1970; Craig and Vokes 1993). The overall reactions are initiated by the oxidation of sulfide minerals by ...

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(PDF) Pyrite Decay: cause and effect, prevention and cure ...

Pyrite (FeS2) is a common mineral found in igneous, sedimentary and metamorphic rocks; it may be present in petrology, mineral and palaeontological collections. Pyrite decay, or pyrite oxidation, has been recorded since the 19th century and various

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Research on pyrite oxidation and native microorganisms has ...

Jul 16, 2020 · If pyrite was present in the rock, it will oxidize. The team will examine whether this excavation and piling of materials help lead to the release of trace elements as a result of pyrite oxidation, which could have implications for the water quality of homeowners in the area.

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Supergene Oxidation of Copper Deposits: Zoning and ...

that pyrite quantity is critical in determining oxide zone mineralogy. Pyrite is a relatively refractory mineral in the replacement sequence; marcasite oxidizes more quickly than pyrite (Mason and Berry, 1968), and pyrrhotite oxidation is as much as two orders of magnitude faster than oxidation of pyrite (Nicholson and Scharer, 1994). Laboratory

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PYRITE OXIDATION UNDER CIRCUMNEUTRAL pH

The Fe2+ – released by pyrite oxidation – may be further oxidized (3) to Fe3+, decreasing the acidity by consuming a proton: Fe ( aq ) O ( g ) H ( aq ) Fe ( aq ) H 2 O ( aq ) 3 2 2 2 1 1 o (3) The resulting Fe3+ is a stronger oxidizer agent than the oxygen itself, thus it can lead to the oxidation of pyrite

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