Abstract

Published and authors’ own data have been used to create a unified mathematical model describing the distribution of uranyl nitrate, nitric acid, and tetravalent elements in TBP with consideration for its dilution in their distribution in neutral and acid systems in a wide range of component concentrations. As the base values of the concentration equilibrium constants were taken their values calculated for pure TBP. In this case, raising the diluent concentration leads to a linear dependence of the logarithms of the extraction constants on the TBP concentration with a parameter a the value of which reflects the influence exerted by the nature of a diluent. It is assumed that, simultaneously, there occur several complexation reactions in the aqueous and organic phases and a nonstoichiometric physicochemical interaction of the components. The values of the equilibrium constants of the extraction reactions and the corresponding parameters a were determined for tetravalent thorium, uranium, plutonium, neptunium, zirconium, and hafnium, which made it possible to describe their extraction with TBP solutions in a hydrocarbon diluent at concentration of the extractive agent of 5 to 100 vol %. The error in calculations of the distribution coefficients in terms of the model does not exceed 12%.

中文翻译：

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TBP稀释统一模型在描述硝酸盐溶液中四价锆和Act系元素硝酸盐萃取中的应用

摘要

已发表的和作者自己的数据已用于创建一个统一的数学模型，该模型描述了TBP中硝酸铀酰，硝酸和四价元素的分布，并考虑了它们在中性和酸性系统中的分布在各种浓度范围内的稀释度。作为浓度平衡常数的基值，采用它们的纯TBP计算值。在这种情况下，提高稀释剂浓度会导致萃取常数的对数与TBP浓度的线性关系（参数为a）其值反映了稀释剂性质所产生的影响。假设同时在水相和有机相中发生了几种络合反应，并且各组分之间发生了非化学计量的物理化学相互作用。确定了四价th，铀，p，n，z和锆的萃取反应的平衡常数值和相应的参数a，这使得描述在烃类稀释剂中以TBP溶液萃取浓度为的萃取反应成为可能。 5至100体积％的萃取剂。就模型而言，分配系数的计算误差不超过12％。