Effect of Copper Ion Concentration on the Structure of Copper Deposits Cemented on Pure Aluminum Discs: A Scanning Electron Microscopic Study

Abstract

Copper from leach liquors is recovered commercially by cementing elemental copper on scrap iron. Consumption of scrap iron in the cementation reactions is usually much higher than the theoretically required amount1. Aluminum in the form of beverage and beer cans have been tried as a substitute for scrap iron in the copper cementation process, and MacKinnon and Ingraham2,3 were the first to report the experimental results. The rate of a cementation reaction is computed using the first-order rate equation4, and the specific rate constant (k0, cm sec-1) of the reaction is proportional to the effective cathodic surface area. The change in the rate, therefore, is a function of the deposit structure and morphology. A knowledge of the optimum copper ion concentration ([Cu2+]) value for a maximum rate at ambient temperatures is a desirable factor for any cementation process. This paper reports the structural studies of the copper deposits in the copper-pure aluminum system for various initial [Cu2+] values at ambient temperatures.