Extraction of uranium from acidic media with a novel synergistic mixture of di-nonyl phenyl phosphoric acid and tri-n-octyl phosphine oxide

摘要

The extraction of uranium from aqueous acidic solutions of nitrate,perchlorate,sulphate,chloride and phosphate with a novel synergistic mixture of di-nonyl phenyl phosphoric acid (DNPPA) and tri-n-octyl phosphine oxide (TOPO) in an aliphatic hydrocarbon diluent has been studied at varying concentrations of aqueous acids,extractant and uranium.The mole ratio [DNPPA]:[TOPO] has been found to have a significant effect on extraction of uranium.Maximum extraction was found at 2:1 mole ratio and no antagonistic effect was observed at higher concentration of TOPO.The extracted species has been found to be UO_2 (HR_2)_2.TOPO.The extraction order of uranium in aqueous media follows the sequence: perchlorate > nitrate > chloride > sulphate > phosphate.The selectivity of uranium with respect to other metals including Zn,Cu,Ni,Ca,and Fe has been investigated as a function of concentrations of sulphuric acid and extractant.Based on these findings,extraction of uranium has been carried out from leach liquor generated at an industrial plant,using 0.03 M DNPPA + 0.015 M TOPO with high recovery (>99%),selectivity and having added advantage of low inventory cost on extractants.