EXTRACTION OF AM(III), EU(III) AND U(VI) FROM PERCHLORIC-ACID AND MIXTURES OF ACIDS BY DIALKYL-(DIARYL) [DIETHYLCARBAMOYLMETHYL] PHOSPHINE OXIDES

Extraction of Am(III), Eu(III) and U(VI) from perchloric acid solutions by dialkyl(diaryl) (diethylcarbamoylmethyl] phosphine oxides (CMPO) has been investigated. It has been shown that elements are extracted more effectively from perchloric acid solutions than from nitric acid. An "anomalous aryl effect" increases sufficiently in perchloric media as compared with nitric media. Solvate numbers of elements also increase in perchloric acid, they being extremely high for aryl-substituted reagents and not so high for alkyl-substituted compounds. It has been shown that in HNO3 and HClO4 solutions the value of "anomalous aryl effect" directly depends on the difference in values of element solvate numbers in complexes with aryl- and alkyl-substituted CMPO. Am(III), Eu(III) and U(VI) are not practically extracted from phosphoric and sulphuric acids by CMPO solutions. The influence of HClO4 concentration on element extraction from different acid solutions has been studied; a considerable increase of distribution coefficients, in some cases sinergetic increase, has been found. The method of increasing efficiency of element extraction from acid solutions by adding small amounts of HClO4 has been suggested for extraction and preconcentration of Am(III) and U(VI) from HNO3, H3PO4 and H2SO4 solutions,