Vishnevsky A. V., Belogub E. V., Charykova M. V., Krivovichev V. G., Blinov I. A.
Thermodynamics of arsenates, selenites and sulfates in the oxidation zone of sulfide ores. XIV. Minerals of selenium in the oxidation zone of the Jubileynoe massive sulfide deposit, the South Urals
Zapiski RMO (Proceedings of the Russian Mineralogical Society). 2017. V. 146. N 3. P. 17-29
Selenium is an essential trace element in sulfide ores. The selenium minerals (clausthalite, PbSe, tiemannite, HgSe, and naumannite, Ag2Se) have been found with goethite and siderite as newly formed phases in the oxidation zone of the Jubileynoe copper-sulfide ore deposit at the Urals, in Russia. Thermodynamic modeling was used to assess physical-chemical parameters of selenide stability, and estimate the possibility of the Pb, Hg and Ag selenites formation while the oxidation of sulfide ores. Eh—pH diagrams of Fe—S—CO2—H2O, Fe—Se—CO2—H2O systems were calculated for physi cal-chemical formation conditions of the oxidation zone of the Jubileynoe deposit, as well as for systems M—Se—H2O and M—S—H2O (M = Hg, Pb, Ag). Exchange reactions between sulfides and selenides have allowed estimating the ratio of selenium and sulfur activities in the mineral-forming media. It is shown that among selenites of lead, silver and mercury only PbSeO3 compound may be formed theoretically in the oxidation zone of the Jubileynoe deposit.
Key words: selenium, oxidation zone, massive sulfide ores, thermodynamics, modeling.