Electrochemical Phenomena in MnO2-FeS2 Leaching in Dilute HCl. Part 1: Theoretical Derivation of Rate Equations Under Various Limiting Conditions

Abstract

The paper presents a theoretical analysis of MnO2-FeS2 dissolution in acidic media. It is assumed that MnO2 and FeS2 dissolve through the operations of MnO2/Fe2+ and FeS2/Fe3+ corrosion couples. At the mixed potential Em, the half cell reactions establish kinetic equilibria to satisfy charge balance. Kinetic expressions for the mixed potential, Em and the mixed current, im are derived based on the position of Em on different segments of the hypothetical polarization curves. Finally, the mechanism by which the rates of reactions of the two couples balance each other is discussed. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.RésuméLe document présente une analyse theorique de la dissolution du MnO2-FeS2 en milieux acides. On assume que MnO2 et FeS2 se dissolvent par operation des couples de corrosion MnO2/Fe2+ et FeS2/Fe3+. Au potentiel de melange Em les reactions de la demi-cellule etablissent des equilibres cinetiques pour satisfaire a la balance de charge. Les expressions cinetiques du potentiel de melange, Em et du courant de melange, im, sont derivees en se basant sur la position de Em, sur differents segments des courbes hypothetiques de polarisation. Finalement, on discute du mecanisme par lequelles taux des réactions des deux couples se balancent entre eux. © 1998 Canadian Institute of Mining and Metallurgy. Published by Elsevier Science Ltd. All rights reserved.