Leaching characteristics and mechanism of copper flotation tailings in sulfuric acid solution

The copper deposit in Yangla zone of China is large, and its recovery is low only using flotation process. Therefore, the copper in the flotation tailings is leached by sulfuric acid can improve copper recovery. The factors affecting leaching process and the leaching mechanism were investigated in this study. Copper is leached at a rate of 53.8% when initial H2SO4 concentration is 0.428 mol/L, leaching temperature is 348 K, liquid-to-solid ratio is 3: 1, stirring speed is 300 r/min and leaching time is 60 min. Through combine the acid leaching process of tailings with the flotation process of raw ore, copper comprehensive recovery has been improved. Kinetics results show that the leaching process is controlled by internal diffusion with an activation energy of 9.796 kJ/mol. To characterize the mechanism of acid leaching, chemical analysis, X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy were used. The results indicate that the fine size of copper minerals and CaSO4 precipitation which generated during acid leaching process affected the leaching of copper minerals.