NEW METHOD FOR ACTINIDE AND RARE-EARTH ELEMENT RECOVERY BY DIPHENYL[DIBUTYLCARBAMOYLMETHYL]PHOSPHINE OXIDE FROM NITRIC-ACID SOLUTIONS

It has been found for the first time that diphenyl[dibutylcarbamoylmet hyl]phosphine oxide (DPDBCMPO) is able to extract effectively actinide and rare-earth elements from acidic solutions, without its preliminar y dissolution in an organic solvent. DPDBCMPO, taken initially as a so lid powder, is established to form an oily liquid complex DPDBCMPO . H NO3. nH(2)O ('liquid reagent') on contact with 4 M HNO3. Behavior of P r(III), Np, Pu and Am in various oxidation states in the process of th eir extraction by 'liquid reagent' is studied. It has been shown that distribution coefficients of the elements extracted by the 'liquid rea gent' ('LR') are greater than are observed in conventional solvent ext raction ('SE'). The use of aluminum phosphate matrix, containing DPDBC MPO, for isolation of the actinide and rare-earth elements and for the ir subsequent vitrification is suggested. (C) 1998 Elsevier Science S. A.