N,N-乙基,羟乙基羟胺在PUREX流程铀钚分离中的应用

Application of N,N-Ethyl(Hydroxyethyl)Hydroxylamine in the Separation of Pu From U in PUREX Process

为了解N,N-乙基,羟乙基羟胺(EHEH)在PUREX流程铀钚分离中的作用,研究了EHEH对Pu(Ⅳ)的单级反萃取行为及其影响因素。结果表明,EHEH能够迅速地将有机相中的Pu(Ⅳ)还原反萃入水相,相比(o/a)为1∶1,接触时间5 s时,钚的反萃取率接近99%;相比(o/a)为4∶1时,5 s内钚的反萃取率可达到80%,相比增大,Pu的反萃取率降低。低酸、升温和提高EHEH浓度有利于钚的还原反萃取。采用14级逆流串级反萃取实验(还原反萃段8级,补充萃取段6级),模拟PUREX流程1B槽U/Pu分离工艺,在相比(1BX∶1BF∶1BS)为1∶4∶1的条件下,铀的收率大于99.999%,Pu的收率大于99.99%;铀中去钚的分离因数α(Pu/U)=1.1×104;钚中去铀的分离因数α(U/Pu)=3.2×105。EHEH作为还原反萃取剂,可以有效实现铀钚分离。

The reduction back-extraction behavior of Pu（Ⅳ） from 30 % TBP/OK with EHEH was investigated under conditions of different temperatures, different concentration of EHEH and HNO3, various contacting-time and phase ratios respectively. It is shown that Pu（Ⅳ） from organic phase can be rapidly stripped into aqueous phase by EHEH; the batch stripping percentage of Pu（Ⅳ） approach 99% in contacting time of 5 seconds at phase ratio （o/a） 1 ： 1, compared with 89% in 30 seconds at phase ratio （o/a） 4 ： 1. It is also found that the higher reductant concentration, the lower acidity and the higher temperature could speed up the stripping extraction process of Pu. The application of EHEH to separate Pu from U in the 1 B contactor was studied by the 14-stages counter current cascade experiment. It is shown that the recovery percentage of U reaches over 99. 999 % and the recovery percentage of Pu reaches over 99.99% at phase ratio （1BX ： 1BF ： 1BS）1 ： 4 ： 1. The sepa ration factor of Pu from U（α （Pu/U））is 1. 1 × 10^4 ; the separation factor of U from Pu （α （U/Pu）） is 3.2×10^5. The results show that EHEH as an orgnic reductant has obvious effect on the separation of Pu from U.