1. Faculty of Metallurgical and Energy Engineering, Kunming University of Science and Technology, Kunming 650093, China
2. Yunnan Chihong International Germanium Co., Ltd., Qujing 655000, China
3. Chinalco Research Institute of Science and Technology Co., Ltd., Beijing 102209, China
4. State Key Laboratory of Advanced Metallurgy for Non-Ferrous Metals, Kunming 650051, China