Anodic dissolution of galena concentrate in perchloric acid

Abstract

A basic study has been made on the anodic dissolution of lead sulphide ore (galena) in perchloric acid. The electrodes used in the research were fabricated by melting and casting the ore in a suitable mould. The phases which were present in sufficient quantities to be detected by X-ray diffraction were PbS and ZnS. Coulombic efficiencies were determined at 40° C at various levels of pH and current density, and were in the range of 90% for most of the tests. Transient studies revealed a non-uniform surface attack and that the dissolution reaction was irreversible, as indicated by the absence of cathodic currents, in the vicinity of the rest potential. Steady-state studies showed the reaction to be activation controlled and that the rate-determining step was a chemical reaction following the first electron transfer.