Abstract
ABSTRACT This study investigated the electrochemical oxidation behaviors of arsenopyrite in sulfuric acid (pH 1) containing various concentrations of ferric ions by cyclic voltammetry, Tafel polarization curves and electrochemical impedance spectra (EIS) measurements. Results indicated that the addition of ferric ions did not affect the electrochemical dissolution mechanism of arsenopyrite. With the increase of the ferric concentration, the corrosion potential of arsenopyrite shifted positively, and the corrosion current density increased. EIS tests showed that arsenopyrite oxidation consisted of two charge transfer processes, i.e., the release of iron and arsenic from arsenopyrite lattice and the oxidation of elemental sulfur formed on the arsenopyrite surface. The overall oxidation of arsenopyrite was controlled by the oxidation of elemental sulfur. The presence of ferric ions decreased the electron transfer resistances of both processes, contributing to the accelerated dissolution of arsenopyrite. Cyclic voltammetry and Tafel plots implied that the enhanced cathodic reaction was the dominant reason for the improved dissolution of arsenopyrite in the presence of ferric ions.
Published Version
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