CAO Jiang-Ping1,2, YI Zong-Hui1,2, ZHAO Wen-Xia1,2, LIANG Yong-Feng1,2, DI Hong-Wei1,2**
1.College of Chemistry and Chemical Engineering, Ningxia Normal University, Guyuan 756000, China;
2.Engineering and Technology Research Center of Liupanshan Resources,Ningxia Normal University, Guyuan 756000, China