硝酸羟胺用于钚纯化循环的工艺条件优化

采用可控温的单级萃取装置，对羟胺还原反萃取钚的工艺条件进行了优化。实验表明，硝酸肼能够将少量Pu(Ⅳ)还原反萃取到水相，但是当硝酸肼浓度较高时，硝酸肼则表现出盐析效应，抑制钚的还原反萃取；对于钚还原反萃取工艺来说，当保持进料中羟胺与钚的摩尔数之比为定值时（在50℃时n (HAN)/ n (Pu)=2～3较为适宜），增大还原剂流量能够提高钚的收率，但同时会降低钚的浓缩倍数；温度升高时，硝酸氧化Pu(Ⅲ)的反应速率加快，使得钚在有机相中的浓度有所升高；当溶液中离子强度较高时，在盐析效应的作用下，Pu(Ⅲ)的分配比随离子强度的提高而升高，导致钚在有机相中的浓度上升。

Process Optimization of Plutonium Purification Cycle Based on Hydroxylamine Nitrate

The process of Pu reductive stripping by hydroxylamine nitrate in plutonium purification cycle was optimized by the single extraction experiments. Hydrazine nitrate can reduce a small quantity of Pu(Ⅳ) and strip it from 30%TBP-kerosene into an aqueous phase, but can suppress the plutonium reductive stripping with increasing hydrazine nitrate concentration, where hydrazine nitrate plays a role as a salting-out agent. For the Pu purification cycle, the Pu recovery can be improved by enhancing the reductant flow when keep the HAN/Pu molar ratios invariable. 2.3 is feasible for the HAN/Pu molar ratios when the temperature is 50℃. Pu concentration in organic phase increases with raising the reaction temperature because reaction rate of HNO₃ with Pu(Ⅲ) is accelerated, and also increases with increasing ionic strength because the distribution coefficient of Pu(Ⅲ) is amplified due to the salting-out effect.