Analysis of Tertiary Current Distribution Modeling in a Turbulent Flow inside Parallel-Plate Electrochemical Reactor Used for Copper Recovery

The effect of hydrodynamics and electrical field on the performance of electrochemical cells is a central issue in electrochemical reactor engineering. This work presents an approach for such issue by modeling the effect of hydrodynamics on the mass transport and tertiary current and potential distribution in a parallel-plate electrochemical reactor used to study the copper recovery process. The operating conditions of the reactor were in turbulent regime and under charge and mass transfer mixed control. For hydrodynamics, the Reynolds averaged Navier–Stokes (RANS) equations, the standard k–ε turbulence model and wall functions were used. The mass transfer model was a combination of the convection–diffusion equation and a wall function adapted for mass transfer. The Butler-Volmer kinetics for copper reduction and simplified Tafel equations for water oxidation were also included in the model. The electrical continuity equation was used for evaluating the ohmic potential drop. An important part of the proposed numerical modeling is the concentration wall function that allows linking the transport equations with Cu²⁺ concentration at the interface in order to obtain, along with interfacial potential, the electrode kinetics. Using this approach it was possible to model a very complex interrelation between physical phenomena and the electrochemical reaction taking place in a reactor under a turbulent flow regime using moderate computer resources. The numerical results obtained are in agreement with experimental data of mass transfer coefficient and current-potential behavior. Fig 1 illustrate the effect of the velocity field on the overpotential distribution over the cathode.