P204-HCl-H_3cit体系铈镨分配比和分离系数的研究

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铈和镨分配比、分离系数及萃取容量的影响.采用FT-IR光谱仪分析了铈镨分离系数提高的机理.实验结果表明:在P204-HCl-H3cit体系中,铈镨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=1.0、柠檬酸浓度=0.25mol/L时,铈和镨的最大分离系数为1.71,稀土的最大萃取容量为27g/L,其指标优于相同酸度下的皂化P204-HCl体系.

Study on Distribution Ratio and Separation Coefficient of Cerium and Praseodymium in P204-HCl-H3cit System

The effects of the feed acidity and citric acid (H3cit) concentration on the distribution ratio and the separation coefficient of Ce(III) and Pr(III) and the extraction capacity were investigated in P204-HCl-H3cit system. The result showed that the distribution ratio and the separation coefficient both decrease with increasing feed acidity and increase with increasing citric acid concentration, and the extraction capacity increases with increasing citric acidity concentration in P204-HCl-H3cit system. The mechanism of the increase of the separation coefficient of Ce(III) and Pr(III) was analyzed by FT-IR spectra. When citric acid concentration is 0.25 mol·L^-1 and pH value of feed acidity is 1.0, the maximum separation coefficient comes up to 1.71 with maximum extraction capacity 27 g/L. The performance index is therefore proved superior to that in saponified P204-HCl system.