An investigation of surface oxidation of pyrite and pyrrhotite by linear potential sweep voltammetry

Abstract

The products of surface oxidation of pyrite and pyrrhotite have been determined from analysis of linear potential sweep voltammograms. Pyrite oxidizes to both sulphur and sulphate. The formation of sulphur is restricted to the order of a monolayer at pH 9.2 and 13, but significant yield occurs at pH 4.6. The proportion of sulphate formed increases rapidly with increase in potential. Sulphur is the major product of pyrrhotite oxidation at pH 4.6, 9.2 and 13. Sulphate is also formed in significant quantities, particularly in the alkaline solutions. Oxidation of pyrrhotite is strongly inhibited by the surface ferric oxide produced.