低浓度轻稀土离子的选择性萃取分离  

Selective extraction and separation of low-concentration light rare earth ions

作　　者：吴江华 张杜超 杨天足 WU Jianghua;ZHANG Duchao;YANG Tianzu(School of Metallurgy and Environment,Central South University,Changsha 410008,China)

机构地区：[1]中南大学冶金与环境学院,长沙410008

出　　处：《中国有色金属学报》2024年第2期625-639,共15页The Chinese Journal of Nonferrous Metals

基　　金：国家自然科学基金资助项目(51704039);湖南省自然科学基金资助项目(2017JJ3320)。

摘　　要：本文研究了采用1,7-二氮杂15冠5醚(2N15C5)从多离子共存的复杂硫酸盐体系中选择性萃取分离轻稀土离子的过程。结果表明:水相中的高浓度杂质离子主要通过诱导稀土硫酸钠盐沉淀的生成来影响复杂硫酸盐体系的稳定性,从而降低2N15C5对轻稀土离子的选择性萃取分配比。在水相pH<2.0、[SO_(4)^(2-)]/Σ[RE^(3+)]<10、相比R_(O/A)=2∶1、混相时间10 min的情况下,轻稀土离子组与重稀土离子组的单级萃取分离系数可达23.0023,经5级逆流萃取处理后,对应的累积萃取分离系数可达36.7016。该分组萃取分离法可从离子吸附型稀土矿原地浸出尾液中选择性萃取分离低浓度轻稀土离子,负载有机相经稀盐酸洗杂、乙二胺四乙酸溶液反萃处理后可得到轻稀土富集液,轻稀土离子的综合收率为83.98%。This paper studied the selective extraction of light rare earth ions from complex sulfate systems with multiple-ions coexistence using aza-crown ether(2N15C5).The results show that high concentration impurity ions in the aqueous phase mainly affect the stability of complex sulfate system by inducing the precipitation of rare earth sulfate sodium salt,thereby reducing the selectivity and distribution ratio of 2N15C5 for light rare earth ions.Under the conditions of pH<2.0,[SO_(4)^(2-)]/Σ[RE^(3+)]<10 in aqueous phase,phase ratio R_(O/A)=2∶1,mixing time of 10 min and coexistence of multiple impurity cations,the single-stage extraction coefficient of light rare earth ion group and heavy rare earth ion group can reach 23.0023,and the corresponding cumulative extraction coefficient after 5-stage counter-current extraction can reach 36.7016.This grouped-extraction method can selectively extract low-concentration light rare earth ions from the in-suit leaching tailing liquid of ion-adsorbed rare earth ores.The enriched light rare earth solution can be obtained from the loaded organic phase by washing with dilute hydrochloric acid and anti-extracting with ethylenediaminetetraacetic acid(HEDTA)solution.The overall recovery rate of light rare earth ions is 83.98%.

关 键 词：氮杂冠醚 低浓度轻稀土离子 选择性萃取 分组萃取 原地浸出尾液 

分 类 号：TF845.6[冶金工程—有色金属冶金]