LIQUID-LIQUID-EXTRACTION OF URANIUM FROM PHOSPHORIC-ACID BY HDEHP-CYANEX-921 MIXTURE

The extraction of uranyl ions from different phosphoric acid media by CYANEX-921 (a commercial trioctyl phosphine oxide) mixed with di-2-eth ylhexyl phosphoric acid diluted with odourless kerosene has been inves tigated. The effect of phosphoric acid, CYANEX-921 and HDEHP concentra tions, as well as temperature on the extraction were studied. The extr action rate for UO22+ transfer from 5 M phosphoric acid to the organic phase containing a CYANEX-921-HDEHP mixture in a single drop column w ithout external force was also studied. The mass transfer of uranium i n the organic extractant single drop was investigated in terms of drop size, uranium concentration as well as other parameters. The extracti on rate was found to be mainly dependent on uranium, HDEHP and phospho ric acid concentrations, and found to be mainly controlled by diffusio n in the single drop. Further, it was found that CYANEX-921 can substi tute TOPO to synergise the extraction of UO22+ by HDEHP.