亚硝酸分配比测定及其初步模拟计算

Purex流程的计算机模拟研究有助于流程的优化和改进。HNO2不可避免地存在于Purex流程中,影响许多重要核素的萃取,因此需要建立HNO2的分配比模型,以完善Purex流程计算机模拟程序。采用酸碱滴定法和重氮偶联法同时测定了平衡水相和有机相中HNO3和HNO2的浓度,进而获得分配比数据。在研究范围内,水相HNO2浓度对HNO2和HNO3的分配比影响不明显。水相HNO3浓度升高,HNO2的分配比下降,而HNO3的分配比先升高后下降。有机相中TBP浓度升高,HNO2和HNO3的分配比均增加。初步建立了HNO2分配比与水相酸度和自由TBP的关联式,计算结果与实验值比较吻合。

Distribution Coefficient of Nitrous Acid and Its Computer Simulation

Computer simulation of Purex process can facilitate the optimization and improvement of the process. Nitrous acid is inevitably present in Purex process, which also affects the extraction of some important nuclides, thus, it is desired to build a HNO₂ distribution model which could be incorporated into Purex computer simulation code. In this work base titration and diazotization-coupling reaction was used to determine the concentration of HNO₃ and HNO₂ in both equilibrium aqueous and organic phase, to determine their distribution ratio. Nitrous acid concentration had little effect on the distribution ratio of HNO₃ and HNO₂. As HNO₃ concentration increases, the distribution ratio of HNO₃ increases first then decreases, while the distribution ratio of HNO₂ decreases. The distribution ratio of HNO₃ and HNO₂ increase with TBP concentration. A formula was established to correlate the distribution ratio of HNO₂ with HNO₃ concentration and free TBP concentration. The calculated results agree well with the experiment results.