Influence of inorganic anions on electrochemical behaviour of pyrite

This work gives an investigation of pyrite behaviour during anodic oxidation in solutions of four inorganic acids: sulphuric, hydrochloric, phosphoric and perichloric acid. In wider range of concentrations, the influence of acids on following parameters was investigated: rate of establishment and corrosion potential value, Tafel's slope, corrosion current and electrodic reaction order. Based on potentiodynamic and chronoamperometric investigations, it was found out that pyrite oxidation is developed in three regions conditionally named active, passive and transpassive region. It was also found out that pyrite is intensively dissolved at potentials higher than 0.75 V versus SCE and that oxidation rate of pyrite is the highest in hydrochloric acid solutions (>= 1 M HCl). By comparison of obtained results, it was concluded that there are no distinctive differences in pyrite behaviour during anodic oxidation in solutions of investigated acids. (c) 2005 Elsevier Ltd. All rights reserved.