Recovery of copper from spent catalyst using acid leaching followed by electrodeposition on square rotating cylinder

In this study, the kinetics of acid leaching of a spent catalyst containing CuO was investigated. The effect of key parameters such as type of acid (H2SO4, HCl, Oxalic acid), concentration of acid (0.5–2 M), stirring speed (200–600 rpm), liquid to solid ratio (40–200 ml/g) and temperature (27–55 °C) on the rate of leaching was determined experimentally. The treatment of present leaching data using shrinking core model (SCM) revealed that diffusion through the catalyst's ash layer is the rate controlling step. Activation energy values confirmed also the diffusion controlled nature of the leaching process. Kinetics of copper recovery from synthetic leach liquor by electrochemical deposition on square rotating cylinder was studied under different conditions using limiting current technique measurements. The rate of copper electrodeposition was expressed by the mass transfer coefficient. The present results showed that mass transfer coefficient increases with decreasing initial concentration of copper ions and increasing rpm. The present mass transfer data for copper deposition under constant current electrolysis at square rotating cylinder was correlated by the following dimensionless equation: Sh = 0.4557 Sc0.33 Re0.59 for the conditions 657