Recovery of rare earth elements and thorium from acid leaching residue of ionic rare earth concentrates  

作　　者：Qiaofa Lan Xiaolin Zhang Fei Niu Donghui Liu Leiting Shen Youming Yang 

机构地区：[1]Faculty of Materials Metallurgy and Chemistry,Jiangxi University of Science and Technology,Ganzhou,341000,China [2]National Engineering Research Center for Ionic Rare Earth,Ganzhou,341000,China [3]School of Metallurgy and Environment,Central South University,Changsha,410083,China [4]Guangdong Provincial Key Lab of R&D for Resource Utilization and Disposal of Hazardous Liquids,Shenzhen,518057,China [5]School of Rare Earth and New Materials Engineering,Gannan University of Science and Technology,Ganzhou,341000,China [6]Key Laboratory of Development and Application of Ionic Rare Earth Resources(Jiangxi University of Science and Technology),Ministry of Education,Ganzhou,341000,China

出　　处：《Journal of Rare Earths》2025年第4期794-804,I0006,共12页稀土学报(英文版)

基　　金：supported by the National Key Research and Development Program of China(2020YFC1909001);the Natural Science Foundation of Jiangxi Province(20202BABL214024)。

摘　　要：The acid leaching residue(ALR)of ionic rare earth(IRE)concentrates containing radioactive elements such as thorium(Th)is classified as low-level radioactive waste.ALR holds valuable strategic resources such as rare earth and Th,while improper long-term heaping storage of ALR poses a substantial environmental risk.This paper proposes a comprehensive process involving low-temperature roasting,hydrochloric acid leaching,single extractant enrichment,and stepwise stripping to recover rare earth elements and thorium from ALR.The achieved leaching efficiencies are 80.11%of LnY,99.43%of Sc(Ⅲ),and 98.67%of Th(Ⅳ)after the carbonization of the organic phase in the ALR through low-temperature roasting.Despite large amounts of acid and impurities present in the leachate,2-ethylhexyl phosphonic acid mono 2-ethylhexyl ester(HEHEHP)still exhibits nearly 100%extraction efficiency for Sc(Ⅲ)and Th(Ⅳ).The effective separation of LnY,Th(Ⅳ),and Sc(Ⅲ)was achieved by implementing fractional extraction enrichment of Th(Ⅳ)and Sc(Ⅲ),followed by Th(Ⅳ)removal through H_(2)SO_(4)and Sc(Ⅲ)removal via NaOH from the loaded organic phase.This scheme successfully achieves a recovery of RE and Th and offers a viable solution for the safe disposal of ALR.

关 键 词：Low-level radioactive waste Rare earths THORIUM Solvent extraction Resource recovery 

分 类 号：TF845[冶金工程—有色金属冶金]