The reactions of metal sulphides with molten potassium nitrate

Abstract

The reactions of TiS₂, VS, Cr₂S₃, MnS, FeS, CoS, NiS, CuS and ZnS with molten potassium nitrate were studied. In the melt, Ti, Ni, Cu and Zn metal cations exhibited acid-base reactions and were precipitated as metal oxides whereas V, Cr, Mn, Fe and Co metal cations showed oxidation-reduction as well as acid-base reactions and were converted into VO₃^-, CrO₄^2-, MnO₂, Fe₂O₃ and Co₃O₄ respectively. The sulphide sulphur in all cases was oxidized to sulphate and the nitrate melt was reduced to nitrite and oxides of nitrogen. The stoichiometries of these reactions have been established.