中文摘要：

针对在高酸度下二（2-乙基己基）磷酸（P204）萃取轻稀土氯化物时，La3＋、Ce3＋、Pr3＋、Nd3＋之间分离系数较低的问题，以H3tit—HCl—RECl3溶液为水相，1．5mol／LP204-煤油为有机相，进行了单级萃取实验，实验结果表明，P204在萃取高酸度稀土溶液时（pH=1．0）轻稀土分离系数和有机萃取量明显高于无柠檬酸（H3cit）的萃取体系。考察了P204萃取分离柠檬酸轻稀土时料液酸度、柠檬酸浓度、料液浓度对分离系数的影响，并与生产实际中皂化P204-HCl体系Ce／Pr分离生产线的萃取结果进行了对比，其结果说明，由于柠檬酸的加入强化了Ce和Pr的分离过程，所以在柠檬酸体系中Ce／Pr的分离效果优于盐酸体系。

英文摘要：

In the extraction process of light rare earth chloride with P204, the separation coefficient of La（ Ⅲ ）, Ce（ Ⅲ ）,Pr（ Ⅲ ） and Nd （ Ⅲ ） is lower at high acidity. According to this problem, in this thesis, the single - stage extraction experiments have been studied.The results indicated that the separation coefficient of light rare earth and extract capacity of organic phase were evidently higher than those in the system without citric acid.The effects of feed acidity,feed concentration and citric acid concentration on separation coefficient were investigated. The results showed that the separation process of Ce（ Ⅲ ） and Pr（ Ⅲ ） was strengthened by adding citric acid.Therefore, the separation efficiency of Ce（ Ⅲ ） and Pr（ Ⅲ ） in H3cit system is superior to that in HCl system.