甲基膦酸二甲庚酯对硝酸介质中Pu(Ⅳ)的萃取

研究了 HNO3介质中甲基膦酸二甲庚酯(DMHMP) 对Pu(Ⅳ)的萃取性能，考察了DMHMP浓度、NO-3浓度、HNO3浓度以及温度对Pu(Ⅳ)分配比的影响。确定了DMHMP萃取Pu(Ⅳ)的萃合物的组成为Pu(NO₃)₄·2DMHMP，其萃取反应方程式为： Pu⁴⁺_(a)+2DMHMP_(o)+4NO^-_3(a) Pu(NO₃)₄·2DMHMP_(o) 其中Pu(Ⅳ)与NO^-₃形成中性分子，再与DMHMP结合成为中性配合物进入有机相。在实验范围内Pu(Ⅳ)分配比与DMHMP浓度的平方、NO^-₃浓度的四次方成正比，萃取过程为放热反应，反应的焓变为-34.46 kJ/mol。

Extraction of Pu(Ⅳ)in Nitric Acid Medium With Di(1-Methyl-Heptyl)Methyl Phosphonate

The extraction behavior of Pu(Ⅳ)in HNO₃ medium with di(1-methyl-heptyl)methyl phosphonate(DMHMP)was studied.The effects of DMHMP concentration,NO-3 concentration,HNO₃ concentration and temperature on Pu(Ⅳ)distribution ratio were investigated.The complex formation of Pu(Ⅳ)with DMHMP is Pu(NO₃)₄·2 DMHMP and the extraction reaction equation is determined as follows:Pu⁴⁺+2DMHMP_(o)+4NO3-Pu(NO₃)₄·2DMHMP_(o)Pu(Ⅳ)is formed neutral molecules with NO-3,which then combine with DMHMP to form a neutral complex and enter the organic phase.Pu(Ⅳ)distribution ratio is proportional to the square of DMHMP concentration and the fourth power of NO^-₃ concentration.The extraction reaction is exothermic,and the enthalpy of the reaction is-34.46 kJ/mol.