中文摘要：

针对P204萃取剂在HCl体系中高酸度下镧铈分离系数较低的问题，研究了含有柠檬酸（H3cit）的P204-HCl体系中，料液酸度与柠檬酸浓度对镧铈分配比和分离系数及萃取容量的影响。采用FT—IR方法分析了镧铈分离系数提高的机理。实验结果表明：在P204-HCl-H3cit体系中，镧铈的分配比和分离系数随酸度的增大而降低，随柠檬酸浓度的增加而提高，稀土元素的萃取容量随柠檬酸浓度的增大而提高。当料液酸度pH值为1．0、柠檬酸浓度为0．25mol／L时，镧和铈的分离系数为4．1，稀土的最大萃取容量为24g／L，其指标优于相同酸度下的皂化P204-HCl体系。

英文摘要：

In view of low separation factor of La（ Ⅲ ） and Ce（ Ⅲ ） in P204-HCl system, study was made of the effects of the feed solution acidity and citric acid（H3cit） concentration on the distribution ratio and the separation factor of La（ Ⅲ ） and Ce（ Ⅲ ）and the extraction capacity. The mechanism of the increase of the La （ Ⅲ ） and Ce（ Ⅲ ） separation factor was analyzed by FT-IR method. The experiment results showed that in P204-HCl-H3cit system,La and Ce distribution ratio and separation factor were lower with higher acidity but higher with higher citric acid concentration, while RE element extraction capacity was increased with higher citric acid concentration. With acid concentration 0.25 mol/L and feed acidity pH = 1.0, La and Ce separation factor was 4.1 ,and the maximum RE element extraction capacity was 24 g/L,which was superior to saponified P204-HCl system with the same acidity.