The oxidation of a pure pyrite by Thiobacillus ferrooxidans is not really a constant phenomenon; it must be considered to be more like a succession of different steps which need characterization. Electrochemical studies using a combination of a platinum electrode and a specific pyrite electrode (packed-ground-pyrite electrode) revealed four steps in the bioleaching process. Each step can be ide...

23 24 Large rounded pyrite grains (>1 mm), commonly referred to as ‘buckshot’ pyrites, are a characteristic feature of 25 the auriferous conglomerates (reefs) in the Witwatersrand and Ventersdorp supergroups. Detailed petrographic 26 analyses of the reefs indicated that the vast majority of the buckshot pyrites are of reworked sedimentary origin, 27 i.e., that the pyrite originally formed in th...

Cellular exposure to particulate matter with concomitant formation of reactive oxygen species (ROS) and oxidization of biomolecules may lead to negative health outcomes. Evaluating the particle-induced formation of ROS and the oxidation products from reaction of ROS with biomolecules is useful for gaining a mechanistic understanding of particle-induced oxidative stress. Aqueous suspensions of p...

The formation of pyrite (FeS2) from iron monosulfide precursors in anoxic sediments has been suggested to proceed via mackinawite (FeS) and greigite (Fe3S4). Despite decades of research, the mechanisms of pyrite formation are not sufficiently understood because solid and dissolved intermediates are oxygen-sensitive and poorly crystalline and therefore notoriously difficult to characterize and q...

Pyrite (FeS2) is a major iron- and sulfur-containing mineral phase in the environment. Oxidation of pyrite by aerobic micro-organisms has been well investigated. However, the reactivity of pyrite under anoxic conditions is still an open question. In the present paper, we summarize field and laboratory data on this chemolithotrophic respiration process with nitrate as terminal electron acceptor....

Despite its exceptional optical absorptivity, suitable band gap, and earth abundance, the low open-circuit voltage of pyrite FeS2 has remained the biggest challenge preventing its use in photovoltaic devices. Two widely-accepted causes are: (i) Fermi level pinning caused by intrinsic surface states that appear as gap states; (ii) presence of the polymorph marcasite. Based on density-functional ...

Leptospirillum sp. str. ZC isolated from bioleaching pulp of zinc concentrate is capable of oxidizing Fe (II) with the optimal temperature of 37oC. In pure culture bacteria is unable to oxidize pyrite, however, its growth together with sulfur oxidizing A.albertensis str.SO-2 significantly enhances the efficiency of pyrite bioleaching. The correlation between pyrite biooxidation and adhesion of ...

To provide the basic information about the release of heavy metals from the pyrite tailings of Huangjiagou pyrite mine, the pyrite tailings were investigated through a series of batch experiments under different initial pH of extractant, temperature, liquid-solid (LS) ratio, and soaking time conditions. Moreover, calcium carbonate was added in the pyrite tailings to determine the reduction effe...

The effect of a diacetylene-containing phospholipid on the oxidation of pyrite, FeS2, was investigated. Earlier work reported by our research group showed that the adsorption of 1,2-bis(10,12-tricosadiynoyl)-sn-glycero-3phosphocholine on pyrite suppressed the extent of its oxidation by about 75% over a specific time period. Results presented here show that the pre-exposure to UV radiation of th...

One of the key-principles of the iron-sulphur world theory is to bring organic molecules close enough to interact with each other, using the surface of pyrite as a substrate in a hydrothermal setting. The present paper explores the relationship of pyrite and organic matter in a hydrothermal setting from the geological record; in hydrothermal calcite veins from Carboniferous limestones in centra...