Electrochemical phenomena in MnO2-FeS2 leaching in dilute HCl. Part 1: Theoretical derivation of rate equations under various limiting conditions

The paper presents a theoretical analysis of MnO2-FeS2 dissolution in acidi c media. It is assumed that MnO2 and FeS2 dissolve through the operations o f MnO2/Fe2+ and FeS2/Fe3+ corrosion couples. Al the mixed potential E-m, th e half cell reactions establish kinetic equilibria to satisfy charge balanc e. Kinetic expressions for the mixed potential, E-m, and the mixed current, i(m), are derived based on the position of E-m on different segments of th e hypothetical polarization curves. Finally, the mechanism by which the rat es of reactions of the two couples balance each ether is discussed. (C) 199 8 Canadian Institute of Mining and Metallurgy. Published by Elsevier Scienc e Ltd. All rights reserved.