THE EXTRACTION OF ACTINIDES BY DIPHENYL(DIBUTYLCARBAMOYLMETHYL)PHOSPHINE OXIDE IN THE ABSENCE OF A SOLVENT

The possibility of changing the aggregate state of several solid mono- and bidentate neutral organophosphorus compounds in contact with vari ous mineral acids was demonstrated. The formation of the liquid phase immiscible with water was observed. The phase exhibits a high extracti on capability with respect to actinides in various oxidation states. T he diphenyl(dibutylcarbamoylmethyl)phosphine oxide-HNO3 extraction sys tem was studied in detail. The composition of the liquid phase was sho wn to be Ph2P(O)CH2C(O)NBu2.HNO3.nH(2)O (n = 2 or 3). The kinetics of formation of this phase from solutions of nitric acid and its salts wa s studied. The organic phase exhibits redox properties, due to which s ome actinides change the oxidation state during extraction. The ''aryl strengthening effect'' was suggested to exist for extraction of Am-II I in the absence of a solvent.