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Chemistry of Acid Mine Drainage Formation
Published in Geoffrey S. Simate, Sehliselo Ndlovu, Acid Mine Drainage, 2021
Arsenopyrite (FeAsS) is the most common arsenic (As) bearing mineral (Saxe et al., 2005). Arsenopyrite and other primary arsenic minerals are formed only under high temperature conditions (Drewniak and Sklodowska, 2013) and are found in a variety of ore deposits, including magmatic, hydrothermal, and porphyry-style systems (Corkhill and Vaughan, 2009; Drewniak and Sklodowska, 2013). It is a common mineral constituent of refractory gold ores (Corkhill and Vaughan, 2009; Andrews and Merkle, 1999) and thus arsenopyrite is often mined, processed to extract the gold and discarded as solid waste (Corkhill and Vaughan, 2009). Other mineral constituents of arsenopyrite are copper and silver (Dos Santos et al., 2017). In addition, natural arsenopyrite samples are always associated with pyrite and are generally found with large domains of pyrite randomly inlaid in its structure (Fleet and Mumin, 1997; Dos Santos et al., 2017).
Minerals of base metals
Published in Francis P. Gudyanga, Minerals in Africa, 2020
Arsenic occurs in many sulphide minerals with the formula MAsS and MAs2 (M = Fe, Ni, Co) and also as a pure elemental crystal. Arsenopyrite (FeAsS), an illustrative mineral which is structurally related to iron pyrite, is one of the major causes of refractoriness in gold. The mineral is unstable in cyanide solution, decomposing to give a cyanicide, arsenite, which can attach onto gold surface thereby inhibiting further interaction between gold and reagents. This results in poor recovery of the gold, a condition of refractoriness.
Sulfurated fertilizers enhance the microbial dissolution and release of arsenic from soils into groundwater by activating arsenate-respiring prokaryotes
Published in Yong-Guan Zhu, Huaming Guo, Prosun Bhattacharya, Jochen Bundschuh, Arslan Ahmad, Ravi Naidu, Environmental Arsenic in a Changing World, 2019
X.C. Zeng, W.X. Shi, W.W. Wu, S.G. Cheng
Arsenic (As) is a highly toxic metalloid that is widely distributed in the environment. It can exist in organic or inorganic forms (Oremland et al., 2003; Zhu et al., 2014). It is present in more than 200 minerals, usually in combination with sulfur and metals (Kirk & Holm, 2004; Smedley & Kinniburgh, 2002; Ferguson et al., 1972). The most common arsenic-bearing mineral is arsenopyrite (Hao et al., 2014; Savage et al., 2004; Zhu et al., 2008). Arsenic typically occurs in four oxidation states: -3, 0, +3 and +5. The most dominant forms in arsenic-contaminated soils and water are As(III) (arsenite) and As(V) (arsenate). Arsenite is more soluble, mobile and toxic than arsenate. Arsenic compounds have been classified as a carcinogen to humans. Acute high-dose exposure to arsenic may cause severe systemic toxicity and death. Low-dose chronic exposure can result in cancers of various organs and tissues, hyperkeratosis, jaundice, neuropathy, diabetes mellitus, cardiovascular diseases, stroke, lung diseases, hepatotoxicity and other severe diseases (Zhu et al., 2014; Maguffin & Kirk 2015; Singh et al., 2015).
Future of photovoltaic materials with emphasis on resource availability, economic geology, criticality, and market size/growth
Published in CIM Journal, 2023
G. J. Simandl, S. Paradis, L. Simandl
Arsenic is a major constituent in arsenides, sulfides, oxides, arsenates, and arsenites. It commonly occurs in metalliferous deposits in close association with Cu, Fe, V, Co, scandium (Sc), Ni, Mn, chromium (Cr), Zn, titanium (Ti), Au, Cd, Pb, Ag, antimony (Sb), P, tungsten (W), and molybdenum (Mo). Arsenopyrite (FeAsS), found in high-temperature hydrothermal precious metal (mainly Au)-bearing and polymetallic veins, is perceived to be the main As-bearing mineral. However, As-rich pyrite [Fe(S,As)2] is probably widespread (Smedley & Kinniburgh, 2002). Arsenic has been recovered from Cu-Au ores (e.g., enargite, Cu3AsS4) and other nonferrous or precious metal-bearing ore minerals found in porphyry Cu deposits, VMS deposits (Long, Peng, & Bradshaw, 2012; Nazari, Radzinski, & Ghahreman, 2017), and “five-element vein type” deposits where it is a major constituent (Scharrer, Kreissl, & Markl, 2019).
The Fate of the Arsenic Species in the Pressure Oxidation of Refractory Gold Ores: Practical and Modelling Aspects
Published in Mineral Processing and Extractive Metallurgy Review, 2023
Wei Sung Ng, Yanhua Liu, Qiankun Wang, Miao Chen
Arsenopyrite is the most abundant arsenic mineral in the Earth’s crust (Smedley and Kinniburgh 2002) and is typically found in high-temperature hydrothermal veins in association with iron sulfides such as pyrite (FeS2) and pyrrhotite (FeS), as well as with tin ores such as cassiterite (SnO2) (Anthony et al. 1990). Less commonly, arsenopyrite can also occur in low-temperature veins along with realgar and orpiment. Formation of arsenopyrite is similar to that of pyrite, with the replacement of sulfur with arsenic groups due to the scarcity of sulfur. The composition of arsenopyrites is roughly 46% arsenic by mass, although this varies as the arsenic-to-sulfide ratio is not always equal to unity. While significant research has been done in the physical removal of arsenopyrite in stages preceding pressure oxidation and leaching, such as in flotation, separation is challenging due to the similarities between the surface properties of arsenopyrite and pyrite (Dunne 2005). This is exacerbated by the fact that arsenopyrite can contain upward of 10 g/t of gold and is often the major carrier of gold (Cabri 1992) due to the aforementioned mineralization of gold and arsenic; discarding the arsenopyrite is thus undesirable from an economical perspective.