Influence of Ferric Ions on the Electrochemical Dissolution Behaviors of Arsenopyrite in Sulfuric Acid of pH 1

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.

KEYWORDS:

• Arsenopyrite
• ferric ions
• electrochemical behaviors
• Tafel polarization plots
• electrochemical impedance spectra

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This study was supported by the Natural Science Basic Research Program of Shaanxi (No. 2020JQ-666) and the National Natural Science Foundation of China (No. 52004198, 51934009).