pyrite mineral oxidation

 · The oxidation of pyrite to release ferrous iron and sulfate ions to solution involves the transfer of seven electrons from each sulfur atom in the mineral to an aqueous oxidant. Because only one or, at most, two electrons can be transferred at a time, the overall oxidation …

particular, radiolysis of water coupled to oxidation of These water/pyrite mixtures were degassed and flame sulfide minerals [3] or elemental sulfur [4] can pro- sealed in quartz tubes of 2 cm diameter and 10 cm duce gradients of partially to fully oxidized sulfur spe- length.

Acidity produced by pyrite oxidation and hydrolysis immediately attacks bone apatite, and immediately destroys calcite. Examination of the reaction between bone apatite and acid is the first step towards targeted interference in this reaction. The mineral apatite serves as a geochemical proxy for bone.

Pyrite is one of the most common and geochemically important sulfide minerals in nature because of its role in the redox recycling of iron (Fe). It is also the primary cause of acid mine drainage (AMD) that is considered as a serious and widespread problem facing the mining and mineral processing in …

 · Landscape to atomic scales: Researchers apply new approach to pyrite oxidation. Pyrite, or fool''s gold, is a common mineral that reacts quickly with oxygen when exposed to …

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.

 · The U(VI) immobilization efficiency and mechanism of natural pyrite were investigated under both acidic and neutral oxidization conditions. The results show that, the final U(VI) removal rate was only 20% under acidic condition; however, a small amount of pyrite oxidation could enhance the immobilization of U(VI) under neutral oxidizing conditions, with the removal rate reaching 95%. A ferric ...

 · The field data were compared to predictions from simulations of pyrite oxidation using a 1-D numerical model. The simulations'' estimates of the amount of Fe and S released over a seven year period (52 kg and 178 kg, respectively) were in reasonably good agreement with those obtained by analysing the tailings (34 kg and 155 kg, respectively).

 · "Pyrite oxidation is a classic geologic and environmental problem, but we know little about the rate of pyrite oxidation occurring in deep rock," said Xin …

 · To the trained eye, the differences between the two minerals are somewhat obvious. Pyrite is magnetic; gold is not. Pyrite can manifest in bizarrely perfect …

According to Moslemia et al. and Corkhill et al., the oxidation of minerals such as Fe 3 O 4 and CuFeS 2 (pyrite group of minerals) under conditions such as pressure, temperature, pH, particles size, concentration, and electrochemical mechanisms results in the release of ferrous ions and other constituents [93,94].

Pyrit, auch als Schwefelkies oder Eisenkies sowie Katzen-oder Narrengold bekannt, ist ein sehr häufig vorkommendes Mineral aus der Klasse der „Sulfide und Sulfosalze". Chemisch gesehen ist es die kubische Modifikation des Eisen(II)-disulfids mit der chemischen Zusammensetzung FeS 2, besteht also aus Eisen und Schwefel im Stoffmengenverhältnis von 1 : 2. ...

 · 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.

Uraninite oxidation may proceed rapidly, particularly if a surface layer of altered uraninite is formed (De Pablo et al. 1999), and pyrite weathers rapidly in the presence of oxygen (Anbar et al. 2007). Instead, it seems more likely that the survival of siderite, uraninite, and pyrite in the

The factors affecting pyrite and pyrrhotite oxidation are similar but the latter has received much less attention. As it is the case for pyrite, an increase in temperature has an increasing effect ...

6.4 Pyrite Surface Functional Groups 148 6.4.1 Pyrite oxidation effects by iron-carbonate complexes. 156 6.5 Kinetics of Pyrite Oxidation 159 6.5.1 Empirical pyrite oxidation rate laws 161 6.5.2 Application of pyrite oxidation kinetics 164 6.5.3 Shrinking core model kinetics 168 6.6 Effect of Anions on Oxidation of Fe2+ 170 CHAPTER 7

The properties of surface films on pyrite have been studied through electrochemical techniques of cyclic voltammetry and AC impedance measurements. The characteristics of the surface films depend on the conditions of oxidation and the source of pyrite. At potentials near 0.0 V, some pyrites have large values of polarization resistance, showing a certain degree of passivity. Some pyrites show ...

Effect of temperature and illumination on pyrite oxidation between pH 2 and 6764 Кб. As pyrite oxidation is the principal cause of the formation of acidic mine drainage (AMD), there hasH. F. Steger and D. L. E., Oxidation of sulźde minerals. 4 Pyrite, chalcopyrite and pyrrhotite, Chem. Read more

 · The oxidation of framboidal pyrite is considered to be fast due to its high specific surface area (SSA) ( Pugh et al., 1984. Pugh, C.E., Hossner, L.R., Dixon, J.B. (1984) Oxidation rate of iron sulfides as affected by surface area, morphology, oxygen concentration and autotrophic bacteria. Soil Science 137, 309–314.

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

Microbiologically accelerated oxidation of pyrite (FeS 2) and other sulfidic minerals is important in both environmental and applied microbiology lfide mineral dissolution by acidophilic bacteria in active and derelict mines and mine spoils produces a noxious, metal-laden, often highly acidic effluent (acid mine drainage [AMD]), which is a serious and widespread form of stream and river ...

The pyrite oxidation and the factors affecting the kinetics of oxidation (0 2, Fe 3+, temperature, pH, E h, and the presence or absence of microorganisms) have been the focus of extensive study because of their importance in both environmental remediation and mineral separation (Blowes et al., 2003).

Pyrite should not be present in the base material, subsoil or bedrock under roads, parking lots, or buildings. Oxidation of pyrite can result in damage to pavement, foundations, and floors. In parts of the country where pyrite is commonly found, construction sites …

 · A pressure oxidation procedure that has gained commercial status for treating gold-bearing arsenopyrite or pyrite employs sulfuric acid (H2SO4) and oxygen as reagents. High temperatures (170° to 190° C) and pressures (up to 400 psig O2) are required to achieve complete oxidation of the sulfide minerals.

Steger, H.F. and Desjardins, L.E., 1978. Oxidation of sulfide minerals, 4. Pyrite, chalco­ pyrite and pyrrhotite. Chern. Geol., 23: 225-237. Samples of pyrite, chalcopyrite and pyrrhotite were subjected to 52° C and 68% Rela­ tive Humidity in air for periods of up to four weeks. The resultant oxidation products

Pyrite oxidation rates were calculated based on the pyrite surface area that would be exposed to gaseous and aqueous phase reactants in dissolution tests. The extent of pyrite liberation, the degree to which pyrite grains are separated from the rock matrix, was determined

 · Pyrite bio-oxidation can improve the gold leaching extent of refractory gold ores, but it can also cause environmental pollution. In this work, common gangue minerals (feldspar, mica, and quartz) were studied to analyze their solubilization under industrial bio-oxidation condition and their effects on pyrite bio-oxidation.

Arsenopyrite and arsenian pyrite are the common carriers of gold in refractory gold deposits. In order to liberate the contained gold, these sulfide minerals are decomposed through accelerated oxidation at high temperature and/or pressure. ... Heterogeneous oxidation on manganese (hydr)oxide mineral surfaces at high pH and on iron (hydr)oxide ...