Leaching isomorphism rare earths from phosphorite ore by sulfuric acid and phosphoric acid

作     者：Hui-Xin Jin Fu-Zhong Wu Xiao-Hao Mao Mei-Long Wang Hong-Yan Xie 

作者机构：College of Materials and Metallurgy Guizhou University Guiyang 550025 China Guizhou Province Key Laboratory of Metallurgical Engineering and Process Energy Saving Guiyang 550025 China 

出 版 物：《Rare Metals》 (稀有金属（英文版）)

年 卷 期：2017年第36卷第10期

页      面：840-850页

核心收录：

学科分类：080603[工学-有色金属冶金] 08[工学] 0806[工学-冶金工程] 

基　　金：financially supported by the National Natural Science Foundation of China (Nos. 51364005  51564003 and 51574094) 

主　　题：Phosphorite Isomorphism Rare earths Leaching Sulfuric acid Phosphoric acid 

摘      要：Most of the phosphorite deposits in the world contain isomorphism rare earths （RE） which are considerably difficult to be leached into solution in the wet phos- phoric acid process. In this work, a systematic study of leaching RE using sulfuric acid, phosphoric acid, mixed acid and two-step leaching of phosphoric acid and sulfuric acid was performed. The aims are to illuminate the main factors that inhibit RE leaching and to provide insights into the further enrichment of RE in the wet phosphoric acid solution. The results indicate that H2SO4 is not an effective acid for leaching isomorphism RE from phosphorite ore. The low RE leaching efficiency attributes to the RE cocrystallized and encapsulated by phosphogypsum （PG） as well as the precipitation of RE by RE sulfates or phosphates. High concentration of H3PO4 can enhance the dissolution and diffusion of RE ions. Hence, the optimized leaching mode of improving RE leaching efficiency is to adequately dissolve phosphorite ores in high concentration of H3PO4 solution and then add H2SO4 to crystallize PG. The effect of corystallization or encapsulation of PG on RE can be decreased due to the crystallizing mode of PG in the bulk solution instead of on the interface of solid reactants. RE leaching efficiency can be high up to 65% by the optimized leaching mode.