An electrochemical study of the effect of chloride ions on the dissolution of chalcopyrite in acidic solutions

Abstract

The electrochemical oxidation of a CuFeS 2 (chalcopyrite) concentrate in a mixed chloride–sulfate electrolyte was studied using carbon paste electrodes. This technique was found to give very reproducible results, and has the advantage that actual concentrate particles can be used in place of large crystalline mineral samples. It will be demonstrated that during the initial stages of leaching, the oxidation of chalcopyrite at low overpotentials is hindered by the formation of a metal-deficient sulfide surface. When chloride ions are present, it will be shown by both transient- and steady-state techniques that the oxidation of the mineral is significantly enhanced. These results have also been found to be in very good agreement with those obtained by direct leaching of the same concentrate.