甲基膦酸二甲庚酯对Zr(Ⅳ)的萃取行为

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

摘要: 以正十二烷为稀释剂，研究了甲基膦酸二甲庚酯(DMHMP)萃取剂对硝酸介质中Zr(Ⅳ)的萃取性能。从3.0 mol/L HNO₃中萃取Zr(Ⅳ)的分配比与萃取剂浓度及硝酸根浓度的关系表明：萃取过程中DMHMP以中性萃取剂形式与Zr(Ⅳ)配位，萃取反应方程式主要为：
Zr⁴⁺+2DMHMP+4NO^-₃=Zr(NO₃)₄·2DMHMP
随着硝酸浓度的增大，还会生成Zr(NO₃)₄·2DMHMP·2HNO₃和Zr(NO₃)₄·2DMHMP·3HNO₃。该反应为放热反应，降低温度有利于DMHMP对Zr(Ⅳ)的萃取。

Abstract: The extraction of Zr(Ⅳ) from nitric acid medium by using di(1-methyl-heptyl)methyl phosphonate(DMHMP) in n-dodecane was studied. The results show that with 3.0 mol/L nitric acid as aqueous phase, the DMHMP molecules coordinate to Zr(Ⅳ) as neutral extraction agent in the extracted complex, and the extraction equation is deduced from the dependency of D(Zr) on the concentrations of extractant in the organic phase and the concentrations of nitrate ion in the aqueous phase. The detailed extraction equation is mainly as follows.
Zr⁴⁺+2DMHMP+4NO^-₃=Zr(NO₃)₄·2DMHMP
There also are Zr(NO₃)₄·2DMHMP·2HNO₃ and Zr(NO₃)₄·2DMHMP·3HNO₃ with the increase of the concentration of nitric acid. The extraction is an exothermic reaction, which shows that decreasing reaction temperature is good to the extraction of Zr(Ⅳ).