The mechanisms of pyrite oxidation and leaching: A fundamental perspective

Chandra, Anand P.; Gerson, Andrea R.

doi:10.1016/j.surfrep.2010.08.003

Cited by 443 publications

(227 citation statements)

References 86 publications

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“…Up to now, researchers have largely focused their attention on outer surface layers, while the underlying extended defective region could seriously affect surface processes in which the charge transport is important. We hypothesize, in particular, that such structures should take part in the inhibited anodic oxidation and oxidative leaching of pyrite, pyrrhotite and other metal sulfides [1][2][3][4][63][64][65][66]. Noteworthy, the above phenomena arise as a result of the sample handling in atmosphere, that is, in the early stages of metal sulfide oxidation.…”

Section: Discussionmentioning

confidence: 99%

“…These minerals are frequently found together with non-ferrous base metals and precious metals in ores and play an important role in the biogeochemical sulfur cycle and other environmental processes [1][2][3][4]. Pyrite (FeS 2 ) has a cubic crystal lattice composed of low-spin ferrous iron and disulfide S 2 2− groups with a bulk band gap of about 0.95 eV [5][6][7]; it is one of the promising materials for photovoltaic [8,9], battery cathode [10,11], thermoelectric [12] and other applications.…”

Section: Introductionmentioning

confidence: 99%

“…It is known from X-ray photoelectron spectroscopy (XPS) and other surface-sensitive techniques [2][3][4][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34] that iron can be easily released from the lattice of these compounds, leaving non-equilibrium metal-deficient surface layers. The resulting surface sulfur enrichment is generally modest for oxidation-resistant pyrite, with intrinsic (fractured) pyrite surfaces possibly even being S-deficient [2][3][4][5][6][17][18][19][20][21][22][23][24][25][26]. In contrast, the metal depleted layer incorporates di-and polysulfide species and low-spin Fe(II) and can be as thick as several micrometers at pyrrhotite reacted in acidic solutions under certain conditions [27][28][29][30][31][32][33][34]…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Mikhlin

Tomashevich

Vorobyev

et al. 2016

Applied Surface Science

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a b s t r a c tHard X-ray photoelectron spectroscopy (HAXPES) using an excitation energy range of 2 keV to 6 keV in combination with Fe K-and S K-edge XANES, measured simultaneously in total electron (TEY) and partial fluorescence yield (PFY) modes, have been applied to study near-surface regions of natural polycrystalline pyrite FeS 2 and pyrrhotite Fe 1−x S before and after etching treatments in an acidic ferric chloride solution. It was found that the following near-surface regions are formed owing to the preferential release of iron from oxidized metal sulfide lattices: (i) a thin, no more than 1-4 nm in depth, outer layer containing polysulfide species, (ii) a layer exhibiting less pronounced stoichiometry deviations and low, if any, concentrations of polysulfide, the composition and dimensions of which vary for pyrite and pyrrhotite and depend on the chemical treatment, and (iii) an extended almost stoichiometric underlayer yielding modified TEY XANES spectra, probably, due to a higher content of defects. We suggest that the extended layered structure should heavily affect the near-surface electronic properties, and processes involving the surface and interfacial charge transfer.

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Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Mikhlin

Tomashevich

Vorobyev

et al. 2016

Applied Surface Science

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“…Temperature has been shown to impact on the weathering rates of pyrite [27], however we assume this effect is negligible over the range observed here. Dissolved oxygen (DO) measurements confirmed that conditions remained oxygenated (7.4-9.4 mg/L) for all samples over the sampling period.…”

Section: Sample Acidification and Leachingmentioning

confidence: 92%

Long-Term Acid-Generating and Metal Leaching Potential of a Sub-Arctic Oil Shale

et al. 2014

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Shales are increasingly being exploited for oil and unconventional gas. Exploitation of sub-arctic oil shales requires the creation of gravel pads to elevate workings above the heaving effects of ground ice. These gravel pads can potentially generate acidic leachate, which can enhance the mobility of metals from the shale. To examine this potential, pyrite-bearing shale originating from sub-Arctic gravel pad sites were subjected to leaching tests for 600 days at initial pH values ranging from 2 to 5, to simulate potential real world conditions. At set times over the 600 day experiment, pH, oxidation reduction potential (ORP), dissolved oxygen and temperature were recorded and small liquid samples withdrawn and analysed for elemental concentrations using total reflection X-ray fluorescence spectrometry (TRXRF). Six of eight shale samples were found to be acid generating, with pH declining and ORP becoming increasingly positive after 100 days. Two of the eight shale samples produced increasingly alkaline leachate conditions with relatively low ORP after 100 days, indicating an inbuilt buffering capacity. By 600 days the buffering capacity of all samples had been consumed and all leachate samples were acidic. TRXRF analyses demonstrated significant potential for the leaching of S, Fe, Ni, Cu, Zn and Mn with greatest concentrations found in reaction vessels with most acidic pH and highest ORP.

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“…The release of acidic and metalliferous drainage into neighbouring waterways, streams, and rivers can be severely environmentally damaging [4,5]. Heavy metals, in particular, bioaccumulate in living organisms, causing a range of diseases and disorders [2,6].…”

Section: Introductionmentioning

confidence: 99%

Heterotrophic Microbial Stimulation through Biosolids Addition for Enhanced Acid Mine Drainage Control

Ogbughalu

Gerson²,

Qian

et al. 2017

Minerals

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Abstract:The effective control and treatment of acid mine drainage (AMD) from sulfide-containing mine wastes is of fundamental importance for current and future long-term sustainable and cost-effective mining industry operations, and for sustainable management of legacy AMD sites. Historically, AMD management has focused on the use of expensive neutralising chemicals to treat toxic leachates. Accordingly, there is a need to develop more cost-effective and efficient methods to prevent AMD at source. Laboratory kinetic leach column experiments, designed to mimic a sulfide-containing waste rock dump, were conducted to assess the potential of organic waste carbon supplements to stimulate heterotrophic microbial growth, and supress pyrite oxidation and AMD production. Microbiological results showed that the addition of biosolids was effective at maintaining high microbial heterotroph populations and preventing AMD generation over a period of 80 weeks, as verified by leachate chemistry and electron microscopy analyses. This research contributes to the ongoing development of a cost effective, multi-barrier geochemical-microbial control strategy for reduced mineral sulfide oxidation rates at source.

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The mechanisms of pyrite oxidation and leaching: A fundamental perspective

Cited by 443 publications

References 86 publications

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Hard X-ray photoelectron and X-ray absorption spectroscopy characterization of oxidized surfaces of iron sulfides

Long-Term Acid-Generating and Metal Leaching Potential of a Sub-Arctic Oil Shale

Heterotrophic Microbial Stimulation through Biosolids Addition for Enhanced Acid Mine Drainage Control

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