1. School of Petrochemical Technology, Lanzhou University of Technology, Pengjiaping Road No. 36, Lanzhou 730050, China
2. National Nickel and Cobalt Advanced Materials Engineering Research Center, Gansu, Lanzhou 730101, P. R. China
3. Lanzhou Jinchuan Technology Park Co., Ltd, Gansu, Lanzhou 730101, P. R. China