Galvanic interaction between chalcopyrite and manganese dioxide in sulfuric acid medium

Dissolution of chalcopyrite and manganese dioxide minerals in the presence of each other in sulfuric acid medium was studied using compact disc electr odes of the minerals under various H2SO4 concentrations (0.05 to 0.5 M). [H +] had a positive effect on the reaction rate. Strong galvanic interaction was observed to take place between chalcopyrite and manganese dioxide, the galvanic interaction predominating over the individual dissolution (self-co rrosion) rates. Evans diagrams constructed from polarization curves of the two minerals were helpful in interpreting the leaching data. The electroche mical nature of the dissolution reaction was analyzed through application o f the Butler-Volmer equation and was confirmed from polarization measuremen ts conducted with the respective mineral electrodes.