Modeling the the effect of non-ideal flow pattern on tertiary current distribution in a filter-press-type electrochemical reactor for copper recovery

This work presents the numerical modeling of the effect of hydrodynamics on mass transport and tertiary current and potential distribution in a filter press type 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 equations and the standard k-epsilon turbulence model 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, simplified Tafel equations for water oxidation and ohmic potential drop through the electrolyte were also incorporated into the model. The strategic 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. (C) 2015 The Institution of Chemical Engineers. Published by Elsevier B.V. All rights reserved.