Open Access
Initiation of aqueous pyrite oxidation by dissolved oxygen and by ferric iron
Carl O. Moses,D.K. Nordstrom,J.S. Herman,Aaron L. Mills +3 more
- Vol. 17
TLDR
In this article, the authors studied aqueous, abiotic pyrite oxidation in oxygen-saturated and anaerobic Fe(III)-saturated systems, and they concluded that Fe is the more important, direct oxidant of pyrites, which is supported by theoretical consideration regarding the low probability of a direct reaction between paramagnetic molecular oxygen and diamagnetic disulfide.Abstract:
The authors studies of aqueous, abiotic pyrite oxidation in oxygen-saturated and anaerobic Fe(III)-saturated systems span pH values from 2 to 9 and include analyses of sulfite, thiosulfate, polythionates, and sulfate. In addition, they evaluated procedures for cleaning oxidation products from pyrite surfaces. As in silicate experiments, the preparation of the pyrite surface is critical to a valid interpretation of the onset of pyrite oxidation. The rates in oxygen-saturated systems (1) were relatively independent of pH, (2) gave linear sulfoxy anion production, (3) produced thiosulfate and polythionates at pH >3.9, and (4) produced intermediate sulfoxy anions only at high stirring rates. In anaerobic Fe(III)-saturated systems no intermediates were observed. From these results, along with the generally faster rate of oxidation in Fe(III)-saturated systems, we conclude that Fe(III) is the more important, direct oxidant of pyrite. This conclusion is supported by theoretical consideration regarding the low probability of a direct reaction between paramagnetic molecular oxygen and diamagnetic disulfide. The authors findings extend earlier models for the pyrite oxidation mechanism because of the larger range of experimental conditions that they have studied. Preliminary results from studies of sphalerite oxidation, in which they have found thiosulfate, support the hypothesis that thiosulfate is a keymore » intermediate related to the reaction mechanisms, independent of the bounding structure of the sulfide mineral.« lessread more
Citations
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Bioleaching review part A: progress in bioleaching: fundamentals and mechanisms of bacterial metal sulfide oxidation.
TL;DR: In this paper, the authors show that the dominance of At. ferrooxidans or Leptospirillum in mesophilic leaching habitats is highly likely to result from differences in their biochemical iron(II) oxidation pathways, especially the involvement of rusticyanin.
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A Compilation of Rate Parameters of Water-Mineral Interaction Kinetics for Application to Geochemical Modeling
TL;DR: In this paper, a general Arrhenius-type rate equation for over 70 minerals, including phases from all the major classes of silicates, most carbonates, and many other non-silicates, were derived from a computer code that simulates an infinitely well-stirred batch reactor, allowing computation of mass transfer as a function of time.
Journal ArticleDOI
Arsenic in Ground Water of the United States: Occurrence and Geochemistry
TL;DR: Arsenic release from iron oxide appears to be the most common cause of widespread arsenic concentrations exceeding 10 μg/L in ground water This can occur in response to different geochemical conditions, including release of arsenic to ground water through reaction of iron oxide with either natural or anthropogenic (i, petroleum products) organic carbon Iron oxide also can release arsenic to alkaline ground water, such as that found in some felsic volcanic rocks and alkaline aquifers of the western United States.
Journal ArticleDOI
(Bio)chemistry of bacterial leaching - direct vs. indirect bioleaching
TL;DR: In this article, a new integral model for bio-leaching is presented, where metal sulfides are degraded by a chemical attack of iron(III) ions and/or protons on the crystal lattice.
Journal ArticleDOI
The kinetics and electrochemical rate-determining step of aqueous pyrite oxidation
TL;DR: In this article, a series of batch and mixed flow reactor experiments were performed to determine the effect of SO42−, Cl−, ionic strength, and dissolved oxygen on the rate of reaction of pyrite with ferric iron.
References
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Journal ArticleDOI
Acidic mine drainage: the rate-determining step
Philip C. Singer,Werner Stumm +1 more
TL;DR: The rate-determining step in the oxidation of iron pyrite and the formation of acidity in streams associated with coal and copper mines isThe oxidation of ferrous iron, and effective pollution abatement necessitates control ling this reaction.
Book
Principles of biochemistry
TL;DR: The principles of biochemistry as discussed by the authors, a.k.a. Principles of Biochemistry (PBI), were used in the development of the biochemistry of the human body.
Journal ArticleDOI
Electronic spectra, photochemistry, and autoxidation mechanism of the sulfite-bisulfite-pyrosulfite systems. SO2-, SO3-, SO4-, and SO5- radicals
E. Hayon,A. Treinin,J. Wilf +2 more