Leaching of Copper Ores: Effects of Operating Variables

Abstract

Leaching of copper from a Jordanian copper ore has been studied using a stirred batch reactor with hydrochloric acid as the main lixiviant, under the following conditions: temperature 25 – 45oC, acid concentration 0.05 – 0.2 N, particle size 462 – 1850 μm, stirring speed of 700 – 1000 rpm, and solid/liquid ratio of 1 – 4 g/L. It was found that the rate of leaching of copper ore with hydrochloric acid or sulfuric acid, increases with temperature and acid concentration, while it decreases with increasing particle size. At the same operating conditions, leaching with sulfuric acid gave slightly greater conversion than leaching with hydrochloric acid, particularly at operating conditions of high temperature, high acid concentration, and small ore particle sizes. A maximum copper dissolution of about 87 % can be recovered at a leaching temperature of 45oC, 462 μm particle size, 0.2 N hydrochloric acid, 1.0 g/L solid to liquid ratio, and 1000 rpm stirring speed. Keeping all these operating parameters constant while decreasing the hydrochloric acid concentration to 0.05 N will decrease the copper dissolution to 83 %. On the other hand, decreasing the leaching temperature to 25oC while keeping the other parameters fixed at 0.2 N, 1.0 g/L solid to liquid ratio, 1000 rpm stirring speed, and a particle size of 462 μm decreases the copper dissolution to 80 %.