The oxidation of arsenic from As(III) to As(V) during copper electrorefining

The oxidation of arsenic from As(III) to As(V) during copper electrorefining was studied. Experimental results showed that during copper electrorefining, the precipitation of impurities As, Sb and Bi in the electrolyte has strong relation with the oxidation. When As(III) and AsT were 5.00 g/L and 10.00 g/L respectively in the initial electrolyte, after copper electrolysis carried out with current density 235 A/m2 at 65 °C for 168 h, the concentrations of Sb and Bi were decreased 35.0% and 18.2% respectively, while without As(III) in the initial electrolyte, under the same conditions, the concentrations of Sb and Bi weren't decreased but increased 12.5% and 9.1% respectively. It was found that the oxidation of arsenic from As(III) to As(V) plays an important role in the precipitation of impurities As, Sb and Bi in copper electrolyte as well, and the oxidation is applicable to the pseudo-first order kinetic model.

► The deposition of As, Sb and Bi relies on As(III) concentration and its oxidization. ► The oxidation of As(III) is applicable to the pseudo first order kinetic model. ► Maintaining As(III) constant enhances the self-purification of electrolyte.