Thermodynamic study of metal sulphides conversion to oxides in hydrometallurgy

This paper presents thermodynamic study of the conversion of metal sulphides to oxides of the CuAg sulphide concentrate as a final product after mechano-chemical leaching of tetrahedrite. The conversion of sulphides to oxides is carried out by oxidation leaching in NaOH solution. The thermodynamic calculation was performed for the sulphide concentrate containing the following sulphides: CuS, CuFeS₂, FeS, Sb₂S₃, As₂S₃, Bi₂S₃ and HgS. Based on the change of Gibbs free energy (ΔG°) and the equilibrium constant (K), conversion of metal sulphides to oxides from the qualitative assessment of the chemical reaction can occur as the result of the thermodynamic reaction abilities