EXTRACTION MECHANISMS OF URANIUM(VI) IONS BY N,N-DIALKYLAMIDES

N,N-dialkylamides are good extractants of UO//2**2** plus ions from nitrate solutions obtained on the dissolution of nuclear irradiated fuels. The extraction mechanism of uranium(VI) ions proved to be rather complex. Two species were identified by spectrophotometry in the organic phase: UO//2(NO//3)//2L//2 and UO//2(NO//3)//3HL, L standing for the amide molecule. In order to investigate the nature of the UO//2(NO//3)//3HL complex, the IR shift vibrations were compared in the following compounds: free amide, HNO//3** minus L, phenol L, UO//2(NO//3)//3HL. The results are discussed.