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

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.