Oxidation of chalcopyrite in the presence of manganese dioxide in hydrochloric acid medium

Dissolution of chalcopyrite in hydrochloric acid medium in the presence of manganese dioxide (manganese ore containing pyrolusite) was studied at diff erent temperatures, acid concentrations and mineral proportions. Chalcopyri te did not dissolve independently, but underwent oxidative dissolution in t he presence of manganese dioxide, via (i) galvanic interaction, (ii) cyclic action of Fe3+/Fe2+ redox couple and (iii) chlorine gas generated by MnO2 dissolution. The extent of occurrence of these phenomena was evaluated, and the last one was observed to be the most effective. At higher solids conce ntration in the slurry galvanic interaction between CuFe2, and MnO2 can als o be significant. Kinetics and mechanism of the process are discussed. (C) 2000 Elsevier Science B.V. All rights reserved.