Efficient mechanochemical leaching of zinc from zinc oxide ores
(1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China;
2. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China)
2. State Key Laboratory of Complex Nonferrous Metal Resources Clean Utilization, Kunming University of Science and Technology, Kunming 650093, China)
Abstract: A basket grinder was used as mechanochemical activation equipment to study low-grade lead–zinc oxide ores in the Lanping area, China and a mechanochemical leaching (MCL) process combining grinding with NaOH solution leaching was proposed for zinc leaching. The effects of leaching temperature, NaOH concentration, leaching time, liquid–solid ratio, and stirring speed on zinc leaching rate were investigated. Experimental results show that under the optimal conditions, the zinc leaching rate of MCL reaches 92.3%, which is 7.2% higher than that of conventional stirring leaching (CSL). And small difference in energy consumption is observed between the two processes, indicating the superiority of MCL. The strengthening mechanism of mechanochemical activation was investigated by analyzing the zinc phase of raw ore, and XRD, SEM-EDS, EPMA and particle size analyses were conducted on leaching residues from different processes under the optimal conditions.
Key words: mechanochemical leaching; mechanical activation; alkaline leaching; zinc oxide ore; basket grinder