Evaluation of galvanic interaction between sphalerite and manganese dioxide through leaching and polarization studies

Dissolution of sphalerite and manganese dioxide minerals in the presence of one another in sulphuric acid medium was studied using compact disc electr odes of the minerals under various H2SO4 concentrations (0.01-0.5M) arid te mperatures (25-60 degrees C). Both [H+] and temperature had a positive effe ct on the reaction rate. Strong galvanic interaction was observed to take p lace between sphalerite and manganese dioxide, the galvanic interaction pre dominating over the individual dissolution (self-corrosion) rates. Evans di agrams constructed from polarization curves of the two minerals were helpfu l in interpreting the leaching data. The electrochemical nature of the diss olution reaction was analysed through the application of the Butler-Volmer equation and was confirmed from polarization measurements conducted with th e respective mineral electrodes.