乙醛肟还原钚的动力学及其在Purex流程铀钚分离中的应用

采用分光光度法研究乙醛肟浓度、酸度、NO^-₃浓度、Fe(Ⅲ)浓度和温度等对乙醛肟还原Pu(Ⅳ)反应的影响，得到了反应速率方程和相应的物化参数。实验表明：提高乙醛肟浓度和温度、降低酸度皆有利于加快乙醛肟与Pu(Ⅳ)反应的速率，而NO^-₃浓度和Fe(Ⅲ)浓度却对反应的速率影响不大；25℃时，该反应的速率常数为（39.51±0.05）(mol/L)^1.1·min^-1，反应活化能E_a=（88.96±9.43）kJ/mol。乙醛肟反萃Pu(Ⅳ)的单级实验和模拟Purex流程1B槽的串级实验结果表明：在以乙醛肟为还原剂的8级反萃、6级补萃的串级实验中，铀的收率大于99.99%，钚的收率为99.99%，铀中去钚的分离系数达到1.05×10⁴，钚中去铀的分离系数达到2.7×10⁵。 

Kinetics of Pu Reduction by Acetaldoxime and Application of Acetaldoxime to Separation of Pu From U in Purex Process

The effects of concentrations of C₂H₄NOH, H⁺, NO^-₃, Fe(Ⅲ) and temperature on the reaction rate of the Pu(Ⅳ) acetaldoxime were studied by spectrophotometry, and then the rate equation and the corresponding parameters were obtained.The reduction rate of Pu(Ⅳ) can be improved by either increasing the acetaldoxime concentration and the temperature, or decreasing the concentration of acid. However, the effects of concentrations of NO^-₃ and Fe³⁺ on the reduction rate of Pu(Ⅳ) are negligible.It is found that the rate constant is (39.51±0.05） (mol/L)^1.1·min^-1 at 25 ℃, and the activation energy is （88.96±9.43） kJ/mol. In the counter current cascade experiments with acetaldoxime used as reductant (in which 6 stages for supplemental extraction, 8 stages for stripping, and ratio of flow is 1BS∶1BF∶1BX＝1∶4∶1), the recoveries are more than 99.99% for U and 99.99% for Pu . The separation factor of Pu from U is 1.05×10⁴, while that of U from Pu is 2.7×10⁵.