1. Guangxi Key Laboratory of Calcium Carbonate, Resources Comprehensive Utilization, College of Materials and Environmental Engineering, Hezhou University, Hezhou 542899, P. R. China
2. Department of Chemical and Materials Engineering, Hefei University, Hefei 230601, P. R. China
3. State Key Laboratory of the Rare, Earth Permanent Magnetic Materials, Earth-Panda Advance Magnetic Material Co., Ltd., Hefei 230601, P. R. China