甲基膦酸二（1-甲庚）酯对Np(Ⅳ)的萃取行为

Extraction of Np(Ⅳ) From Nitric Acid Solution With Di(1-Methyl-Heptyl) Methyl Phosphonate

摘要: 研究了以煤油为稀释剂、甲基膦酸二（1-甲庚）酯（DMHMP）对硝酸介质中Np(Ⅳ)的萃取性能，考察相接触时间、萃取剂浓度、硝酸根浓度、HNO₃浓度和温度对Np(Ⅳ)萃取分配比的影响。萃取过程主要以中性分子形式对Np(Ⅳ)进行萃取，利用斜率分析方法对萃取机理进行了探究，表明萃合物的组成为Np(NO₃)₄·2DMHMP。该反应的焓变为负值，表明萃取反应为放热反应。

Abstract: The extraction of Np(Ⅳ) from nitric acid medium by using di(1-methyl-heptyl) methyl phosphonate diluted in kerosene was investigated. The influences were studied in this research including the contact time, the concentration of DMHMP, HNO₃ as well as nitrate and the temperature. Slope analyses indicate that Np(Ⅳ) is coordinated mainly in the form of neutral molecules and the extractant complex is Np(NO₃)₄·2DMHMP. The value of enthalpy change for the reaction is negative which means that the extraction of Np(Ⅳ) is an exothermic process.