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As one of the crucial factors contributing to coal spontaneous combustion, the oxidation of pyrite is a complex process involving multiple reactions, particularly in the presence of oxidants (Fe3+ and O2) and bacteria. …
Also at Spruce are abundant sceptered quartz. The quartz scepter cluster in the post was collected this summer and has many scepters. But it didn't look like this when it was collected. Pyrite was abundant in the pocket, so later oxidation formed a pervasive coating of dark, rusty, iron oxide on the quartz crystals and everything in the pocket.
Pyrite, also known as iron disulfide (FeS 2), is a ubiquitous metal sulfide mineral on the Earth's crust that plays a crucial role in the global biogeochemical cycling of iron and sulfur [4].In recent decades, pyrite has been demonstrated to be an effective electron donor to facilitate the reduction of nitrate to N 2 through chemoautotrophic denitrification.
1. Pyrite, as the most abundant sulfide mineral on earth, is usually discharged into tailings pond as the gangue mineral after flotation separation (Li and Li 2019; Mu, Peng, and Lauten 2016; Zhang...
Pyrite (FeS 2) stands as the most prevalent metal sulfide mineral in the natural environment.Typically, the mineral is found in association with a variety of valuable sulfide minerals, comprising sphalerite, chalcopyrite, and chalcocite [1], [2].For the beneficiation of copper sulfide ore, froth floatation is an important way for extracting the valuable copper …
At higher temperatures (>about 800 K) or lower oxygen concentrations, pyrite will be transformed by a two-step process: the thermal decomposition of the pyrite to form porous …
Pyrite (FeS 2) is the most common sulfide mineral found in nature, while arsenopyrite (FeAsS) is the most abundant arsenic-bearing mineral [1], [2], [3], [4].These two minerals usually coexist in ore deposits and exhibit remarkably similar flotation behaviors, making their separation difficult [5], [6], [7].Pyrite is the primary raw material for the production of …
Pyrite (FeS 2) is the most abundant sulfide mineral in Earth's crust and its formation and fate are key controls on the biogeochemical cycles of iron (Fe), sulfur (S), carbon, and oxygen (O 2
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 …
Pyrite (FeS2) is one of the most abundant sulfides on Earth and has already been studied in numerous ways for decades because of its rapid oxidation and the associated …
Sulfide mineral. A metal-sulfide compound, such as pyrite (FeS 2), which forms at high temperature (>50°C) in well-crystallized veins or masses and at low temperatures (<50°C) in poorly crystalline and fine-grained particles.. Oxidation. The chemical process of reacting with oxygen. More generally, the chemical process of removing electrons from an atom or group of …
Within waste rock piles, the generation of acid mine drainage is controlled by the oxidation of sulphide minerals. The oxidation of pyrite by oxygen, for example, can be described in simplified form by the following stoichiometric equations (Stumm and Morgan, 1981): (8) FeS 2 + H 2 O + 7 / 2O 2 ⇒ Fe 2+ + 2SO 4 2− + 2H + (9) Fe 2+ + 1 / 4O 2 ...
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 …
Pyrite is an extremely reactive, abundant sulfide in Earth's crust, and its oxidation is an important regulator of biogeochemical processes (1). Oxidative weathering of pyrite (OWP) is coupled to the global budgets of four …
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 …
Pyrite (FeS 2, iron disulfide) is the most abundant and widespread of the earth's sulfide minerals and is frequently found in massive hydrothermal deposits, veins and replacements, igneous rocks and sedimentary beds [1], [2].Pyrite has little economic value but …
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 …
pyrite in till to identify potential mineral deposits in a given area. However, pyrite is easily oxidised in till beds, and thus, alternative methods should be considered. Goethite pseudomorphs are more commonly found in the till sediments as remnants af ter pyrite oxidation. This study evaluates trace
Pyrite oxidation typically is far from equilibrium, whether represented by reaction ( 1 ) (GARRELS and THOMPSON, 1960) or reaction (2) (SMITH et al., 1968), which is the sum of reaction (1) and 14 X reaction (3) (SINGER and STUMM, 1970a). ... The oxidation of sulfide minerals, particularly pyrite, has been extensively reviewed by HISKEY and ...
Diagenetic alteration of magnetic minerals, driven by closely linked C-S-Fe cycles, is highly likely to complicate the paleomagnetic record. In addition to the anomalous diagenetic paleomagnetic signatures caused by ferromagnetic greigite growth, pyrite sulfur isotope compositions are often "heavy" (i.e., δ 34 S pyr > 0). However, the dependencies and …
Pyrite is an environmentally significant mineral being the major contributor to acid rock drainage. Synchrotron based SPEM (scanning photoelectron microscopy) and micro-XPS (X-ray photoelectron spectroscopy) have been used to characterise fresh and oxidised pyrite (FeS 2) with a view to understanding the initial oxidation steps that take place during natural …
Concrete Aggregates. Ian Sims, Bev Brown, in Lea's Chemistry of Cement and Concrete (Fourth Edition), 1998. Pyrite and other metallic materials. Pyrite (iron disulfide, FeS 2) is a …
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.
Phosphate coating has been proven to be an effective way to reduce pyrite oxidation: oxidizing agents (usually H 2 O 2) can oxidize the Fe 2+ on pyrite surface to Fe 3+ and ... For the raw pyrite, Fe(III)-O/-OH/-S-O were related to the slight oxidation on the mineral surface (Fig. 8 a). Compared to raw pyrite, the ratios of Fe(III)-S-O at 713.5 ...
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 …
Monitoring and assessing the environmental consequences of pyrite oxidation are essential for sustainable resource management and ecosystem protection. Addressing these environmental implications is vital for maintaining ecological balance and human health in regions where pyrite minerals are prevalent. Acid Mine Drainage
Similarly, Feng and van Deventer (2010) reported the generation of ferric oxide and sulfate from the oxidation of pyrite in thiosulfate (S 2 O 3 2−) solutions and under oxidative conditions (reaction 2).They proposed that sulfate ions could be formed through the degradation of thiosulfate or by the oxidation of pyrite.
Research highlights Organic compounds is mineralized during later transport in deep groundwater aquifers. Carbonic acid generated by this process stimulates dissolution of silicate minerals. Protons derived from pyrite oxidation also affects weathering in deep groundwater. The identified weathering mechanisms affect base-flow chemistry in boreal …
The amount of FeS2(100) and FeS2(111) oxidation in the H2O/O2 mixture was more than simply the sum of the reaction observed individually in pure O 2 and H2O. This result suggests that there is a synergy between H 2O and O2 in oxidizing pyrite. In all cases, the amount of oxidation that occurred on FeS 2(111) was greater than on FeS2(100).
Jarosite, a signature ARD mineral, was formed during pyrite oxidation. ... Ongoing sulfide-mineral oxidation coupled with depletion of carbonate minerals can lead to extensive acidification and large increases in dissolved metal (e.g., Co, Cu, Ni) concentrations (Blowes et al., 2014). These processes are well understood for metal, mineral and ...