CFD Study of Magnetic Field Effect on the Performance of Copper Electrodeposition Cells

In copper electrodeposition methods, by applying an electric current between two electrodes immersed in an electrolyte containing CuSO4- H2SO4-H2O, copper is deposited on the cathode surface. Presence of magnetic field has a considerable effect on the performance of electrodeposition cells. The most important roles of the magnetic field on these processes are Lorentz force, magnetohydrodynamic (MHD) convection and its interaction with the natural convection induced by the concentration gradient. In this study, an unsteady, two-dimensional copper electrolysis (one phase) and electrowinning (two-phase liquid-gas) cells were simulated in the presence of magnetic field by using Computational Fluid Dynamics (CFD). The equations of Nernst-Planck, momentum and electric potential were solved by finite volume method. The Eulerian-Lagrangian method was used in simulation of two-phase copper electrowinning cell. The simulation results of electrolysis process showed a good agreement in comparison with experimental data of Muhlenhoff et al. After the validation of the model, copper concentration change and velocity profiles of two processes were investigated and compared with each other. The simulation results showed that the MHD interaction with the natural convection and also intrusion layer pile up leads to the velocity decay. As a result, the velocity reduction in the electrowinning process occurs later than in the electrolysis process but its reduction in the second stage of electrowinning process is about 93%, which is much more than 33% in the electrolysis process.