Temperature dependence of the cathodic and anodic kinetics in a copper electrowinning cell based on reactive electrodialysis

The temperature dependence of various kinetic parameters for the copper electrodeposition reaction and for the ferrous to ferric ion oxidation has been experimentally determined. Potentiodynamic sweeps were carried out in a reactive electrodialysis cell in the 30–60∘C range in order to obtain expressions for each parameter as a function of temperature. In the conditions studied, for both reactions, the exchange current density depends on temperature as ln[i0(A/m2)]=-a/T+bln[i0(A/m2)]=-a/T+b and the limiting current density, as |iL(A/m2)|=cT-d|iL(A/m2)|=cT-d. For the copper electrodeposition reaction, the charge transfer coefficient is constant, whereas for the ferrous to ferric ion oxidation it depends on temperature as α=fT2+gT+hα=fT2+gT+h (a–h are constants). These expressions can be used in a temperature-dependent model of a membrane-based copper electrowinning cell.