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Properties of Solids
Published in W. M. Haynes, David R. Lide, Thomas J. Bruno, CRC Handbook of Chemistry and Physics, 2016
W. M. Haynes, David R. Lide, Thomas J. Bruno
Formula Ag3AsS3 Solids AgBr AgCN AgCl AgNO3 AgNa(NO2)2 Ag2O (AlF)2SiO4 Name Silver thioarsenate (Proustite) Silver bromide Silver cyanide Silver chloride Silver nitrate Silver sodium nitrite Silver oxide Aluminum fluosilicate (topaz) ijk
Oxidative Decomposition of Silver Telluride (Ag2Te) Using Hypochlorite in Different Acid Environments
Published in Mineral Processing and Extractive Metallurgy Review, 2022
V.M. Rodríguez-Chávez, J.C. Fuentes-Aceituno, F. Nava-Alonso
The depletion of easily leachable gold and silver deposits has forced the mining industry to explore new processing alternatives to recover the precious metals from different ores. Among the most important silver phases, it is possible to find pyrargyrite, proustite, stephanite and silver telluride (Paterson 1990). The most common mineral phase of silver telluride is hessite (Ag2Te), and it is frequently associated with some gold tellurides, e.g. calaverite (AuTe2), petzite (Ag3AuTe2), krennerite (AuTe2), montbrayite (Au2Te3) and kostovite (CuAuTe4) (Adams 2016). However, according to Celep et al. (2014), these important silver mineral phases present a very low leaching kinetics in cyanide solutions. Furthermore, Wang and Forssberg (1990) reported that gold and silver telluride and selenide species are stable in the presence of cyanide, which suggests that direct leaching of gold and silver with cyanide is probably ineffective. The reported results demonstrate that the leaching kinetics is very slow compared to native gold and electrum (Cornwall and Hisshion 1976; Henley, Clarke and Sauter 2001; Jayasekera, Ritchie and Avraamides 1991; Johnston 1933; Marsden and House 2006; Padmanaban and Lawson 1991). As can be seen, the refractoriness of these type of minerals becomes an important challenge for the scientific and engineering viewpoint. Jha (1987) and Zhang et al. (2010) mentioned that refractoriness of some minerals including the telluride species can be usually solved by modifying the cyanidation conditions or providing an oxidation pretreatment. Roasting prior to cyanidation was the almost universal practice in old days; however, severe environmental regulations related to the toxic emissions have motivated the researchers to develop alternative leaching systems (Hiskey and Atluri 1988). In the case of gold telluride cyanidation, Haque (2007), reported the possibility to accelerate its dissolution using pre-treatments such as: thermal oxidation, roasting, chemical oxidation, (such as acid leaching, alkaline or acid pressure leaching or biological oxidation). In the case of the chemical oxidation of refractory ores, various types of oxidants have been studied e.g. ozone, hydrogen peroxide, permanganate, chlorine, bromine cyanide, Care`s acid, perchlorate, hypochlorite, ferric ion in acid media and oxygen (Canning and Woodcock 1982).