Extraction of Am(III) from different acid media by di-2-ethyl hexyl phosphoric acid containing phosphorous pentoside

The extraction of Am(III) from nitric, hydrochloric, oxalic, phosphoric and hydrofluoric acids was studied using 0.4F di-2-ethyl hexyl phosphoric acid (HDEHP) containing 0.1M phosphorous pentoxide (P2O5) in dodecane/xylene. T he extraction with pure 0.4F HDEHP was found to be negligible from all the media studied. However, the presence of a small amount of P2O5, in it incre ased the extraction substantially. The distribution ratios of Am(III) obtai ned for HDEHP - P2O5 mixture 3M nitric acid containing different concentrat ions of oxalic acid/phosphoric acid/hydrofluoric acid are in the order of 2 00-250. The same for 3M hydrochloric acid is very high (similar to 800). Th ese distribution ratios are sufficiently high for the quantitative extracti on of Am(III) from all the acid media studied, Different reagents such as a mmonium oxalate, sodium oxalate, oxalic acid, hydrofluoric acid, sodium car bonate and potassium sulphate were explored for the back extraction of Am(I II) from 0.4F HDEHP + 0.1M P2O5 in dodecane/xylene. Of these, 0.35M ammoniu m oxalate and 1M sodium carbonate were found to be most suitable. The back extraction of Am(III) was also attempted with water and 1M H2SO4, HNO3, HCl O4 and HCl solutions after allowing the extracted organics to degrade on it s own. It was found that more than 90% of Am could be back extracted with t hese acids. Using this method more than 90% of Am(III) was recovered from n itric acid solutions containing calcium and fluoride ions.