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

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).