Simulation Analysis of Potential Distribution, Ion Concentration Distribution and Natural Convection in Electrolyte During Copper Electrorefining

Abstract

Numerical simulations are widely used to analyze the mass transfer in a cell with the aim of improving the efficiency of electrolysis processes. In this study, galvanostatic electrolysis with CuSO₄–H₂SO₄ aqueous solution as the electrolyte and pure copper as the anode in laboratory scale was modeled in order to examine how to simulate the transport phenomenon of ions in the copper electrorefining. A galvanostatic electrolysis test using an electrolysis apparatus with similar dimensions to the model was also performed, and the measured cell voltage was compared with that estimated by the simulation. In the simulation, Cu²⁺, H⁺, HSO₄⁻ and SO₄²⁻ were assumed to move according to the Nernst–Planck equation while satisfying the electrical neutrality condition in the electrolyte, and the local equilibrium for the dissociation of HSO₄⁻ was also taken into account. The dependence of the diffusion coefficient and mobility of ions on the electrolyte composition was also incorporated into the calculations, aiming to obtain the potential gradient and ion concentration distribution that are close to the actual values.