Extraction of uranium (VI) with DHDECMP-TBP/kerosene from nitric acid solution

The mechanism of extraction of uranium (VI) with TBP/kerosene, DHDECMP/kerosene and DHDECMP-TBP/kerosene from nitric acid solution is studied. The extracted species is found to be UO2(NO3)2·2TBP, UO2(NO3)2·2DHDECMP and UO2(NO3)2·DHDECMP·TBP, respectively. The extracting equilibrium constants K for these systems are directly measured and their thermodynamic functions ΔH, and ΔS are obtained from the dependence of K upon temperature. The distribution ratio of uranium (VI) increases with the increasing in concentration of DHDECMP, TBP or HNO3, but decreases with the increasing in Gd3+ concentration or temperature. The addition of oxalic acid depresses the extraction of uranium (VI), probably dues to its complexion and therefore is beneficial to the stripping of the latter