1. Department of MetallurgyKey Laboratory of Ionic Liquids MetallurgyFaculty of Metallurgical and Energy EngineeringKunming University of Science and Technology Kunming 650093 P.R. China
2. State Key Laboratory of Complex Nonferrous Metal Resources Cleaning Utilization in Yunnan ProvinceKunming University of Science and Technology Kunming 650093 P.R. China