NpO2+与UO22+阳阳离子络合对30%TBP-煤油萃取Np(Ⅴ)性能的影响

通过分光光度法和液闪计数法研究了Np(Ⅴ)与U(Ⅵ)间的阳阳离子络合作用对Np(Ⅴ)在30%TBP-煤油有机相中的萃取分配行为的影响。结果表明：Np(Ⅴ)-U(Ⅵ)阳阳离子络合物可被萃入TBP有机相中，其萃取分配系数较Np(Ⅴ)提高了数倍。随着U浓度在0.12～0.60 mol/L范围内升高，Np(Ⅴ)-U(Ⅵ)阳阳离子络合物萃取分配系数不断增加，当U浓度达到0.72 mol/L时，由于有机相铀饱和度原因，Np(Ⅴ)-U(Ⅵ)阳阳离子络合物萃取分配系数下降。在室温下，水相酸度为3 mol/L、铀浓度为0.60 mol/L、相比（o/a）为2∶1、两相接触时间为1 min时，Np(Ⅴ)的总萃取分配系数约为0.1，萃入有机相中的Np约占Np总量的9%。提高酸度有利于Np(Ⅴ)-U(Ⅵ)阳阳离子络合物的萃取，接触时间在1～8min范围内对萃取无影响。

Influence of NpO2+ and UO22+ Cation-Cation Complex on Np(Ⅴ) Extraction by 30％TBP-Kerosene

The influence of cation-cation complex between Np(Ⅴ) and U(Ⅵ) on the extraction behavior of Np(Ⅴ) in 30%TBP-kerosene has been researched by spectrophotometry and liquid scintillation. The results show that Np(Ⅴ)-U(Ⅵ) cation-cation complex can be extracted into TBP organic phase directly and the distribution ratio is several times higher than Np(Ⅴ).The distribution ratio of Np(Ⅴ)-U(Ⅵ) cation-cation increases with the increasing of U concentration within 0.12-0.60 mol/L. The distribution ratio of Np(Ⅴ)-U(Ⅵ) cation-cation decreases as the U concentration reaches 0.72 mol/L because of the effect of U saturation degree in organic phase. At room temperature, when the concentration of U(Ⅵ) and HNO₃ of solution are 0.6 mol/L and 3 mol/L respectively and the phase ratio (o/a) is 2∶1, the total distribution ratio of Np(Ⅴ) can reaches about 0.1 after 1 min extraction and almost 9% Np is extracted into TBP organic phase. The distribution ratio of Np(Ⅴ)-U(Ⅵ) cation-cation complex increases with the increase of HNO₃ concentration. The contacting time of two phase has no influence on the extraction of Np(Ⅴ)-U(Ⅵ) cation-cation complex.