Abstract
Rates of copper cementation from aqueous solutions of copper sulfate on a gas-sparged iron helical coil were determined under different conditions of Cu2+ concentrations, liquid pH, superficial gas velocity, ferrous sulfate concentration, and the existence of a surface-active agent. The mass transfer coefficient of copper cementation on steel was observed to rise with the 0.52 power of the gas velocity. Decreasing solution pH and the presence of surfactants increased the rate of cementation, while the presence of FeSO4 reduced the rate of cementation. The present results demonstrate that a gas-sparged helical coil is a low-cost high-productivity reactor because of its large area per unit volume and its high mass transfer coefficient, and the ability of the coil to control the solution temperature. The potential applications of the present reactor in recovering copper from dilute leach liquors found by leaching low-grade copper ores and industrial waste solutions were highlighted.