Abstract The modelling of solvent extraction system is important for the process flow sheet design and optimization. The estimation of aqueous phase activity coefficients constitutes the major part of the thermodynamic modelling of solvent extraction system. Hence the selection of suitable activity coefficient models for the accurate description of aqueous electrolyte system encountered in the nuclear fuel reprocessing system is an important task which decides the accuracy and complexity of the modelling. In this work the accuracy of extended UNIQUAC (eUNIQUAC) activity coefficient model for the estimation of uranyl nitrate and nitric acid distribution coefficient in 1.1 M Tri Butyl Phosphate (TBP) and 1.1 M Tri iso Amyl Phosphate (TiAP) have been compared with the eNRTL, Pitzer and SIT activity coefficient models. eUNIQUAC model gave lowest RMSD (%) for the estimation of uranyl nitrate and nitric acid extraction in TiAP and TBP respectively.

中文翻译：

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用于估算硝酸铀酰和硝酸在磷酸溶剂中分配系数的活度系数模型的比较

摘要 溶剂萃取系统的建模对于工艺流程的设计和优化具有重要意义。水相活度系数的估计构成了溶剂萃取系统热力学建模的主要部分。因此，选择合适的活度系数模型来准确描述核燃料后处理系统中遇到的含水电解质系统是一项重要的任务，它决定了建模的准确性和复杂性。在这项工作中，扩展 UNIQUAC (eUNIQUAC) 活度系数模型用于估计 1.1 M 磷酸三丁酯 (TBP) 和 1.1 M 三异戊基磷酸酯 (TiAP) 中硝酸铀酰和硝酸分配系数的准确性已与 eNRTL 进行了比较、Pitzer 和 SIT 活动系数模型。