1. School of Resources and Environmental Engineering, Wuhan University of Technology, Wuhan 430070, P. R. China
2. State Environmental Protection Key Laboratory of Mineral Metallurgical Resources Utilization and Pollution Control, Wuhan University of Science and Technology, Wuhan 430081, P. R. China
3. School of Minerals Processing and Bioengineering, Central South University, Changsha 410083, P. R. China
4. School of Chemical Engineering, The University of Queensland, Brisbane, Queensland 4072, Australia