CFD simulation of an industrial copper electrowinning cell

Abstract

Copper electrowinning is the process of winning a high purity copper from an aqueous pregnant liquor acid electrolyte in the presence of impurities. In this study, a three-dimensional, steady and two-phase (liquid–gas) computational fluid dynamics (CFD) simulation was applied, together with experimental field measurements, to investigate the performance of an industrial electrowinning cell in the Sarcheshmeh Copper Complex, Iran. This simulation was based on Eulerian–Eulerian method. The continuity and momentum equations with inclusion of buoyancy, drag, turbulent dispersion and concentration-related buoyancy forces were solved by the finite volume method. In order to calculate the velocity distribution in the cell, the k–ω turbulence flow model has been used. To find the concentration distribution of copper, the transport equation of copper ions was solved. There was a good agreement between the simulation results and the experimental measured data of the electrowinning cell. After validation of the model, the effects of electrical current density, volumetric flow rate of feed and the distance between the electrodes were studied on the performance of the cell and copper concentration distribution. The simulation results show that there are two upward flows in the cell, one is near the anode because of oxygen generation and the other is near the cathode due to depletion of copper ions from the electrolyte and buoyancy force. In the middle of the cell, the electrolyte recirculation zone causes a downward flow. Increasing electrical current density decreases copper concentration near the cathode and increases gas volume fraction near the anode, which is in accordance with Faraday's Law. With decreasing volumetric flow rate and distance between the electrodes, copper mass concentration on the cathode decreases.