The electrochemical study of pyrite oxidation in the presence of ozone

Ozone is an environment-friendly and effective oxidant in oxidizing resistant minerals. Studies show its favorable effect on pyrite leaching. However, the effect of ozone from the electrochemical perspective is not well-known. This study aims to investigate the impact of ozone on pyrite oxidation from an electrochemical perspective. OCP increased when oxidizing species were present. This increase may be attributed to a rise in the concentration of the oxidizing agent in the electrolyte. CV showed the formation of a weak anodic peak in the potential range of 0.3 to 0.5 V, indicating incomplete surface oxidation in the absence of oxidizing. Also, the increase in the intensity of anodic peaks in the pyrite oxidation condition and the presence of ozone compared to the absence of oxidizing confirmed the improvement of oxidation conditions. In the absence of ozone, the presence of two cathodic peaks C1 and C2 at potentials of 0.45 and -0.3 V, respectively, indicated the reduction of oxidation products, and it is expected that intermediate species, such as FeS and H2S were formed. In the conditions of acidic solution saturated with ozone, the cathodic peak C2 was attributed to the reduction of ozone and oxygen adsorbed on the pyrite surface. Because ozone and saturated oxygen in the solution are more prone to accept electrons compared to oxidation products and intermediate species. Finally, the morphology of the pyrite surface remaining from the electrochemical test was examined by FESEM analysis, which confirmed the effect of ozone on the corrosion of the pyrite surface.