Title: Solvent extraction of trivalent actinides and lanthanides from a mixture of carboxylic and aminopolyacetic acids
Abstract: The purity of di(2-ethylhexyl)phosphoric acid (HDEHP) markedly influenced the separation of cerium from americium in a lactic acid solution containing diethylenetriaminepentaacetic acid (DTPA) but had little influence on separations involving the least extractable rare earths, europium and promethium. Synergism occurred in the solvent extraction of these elements by mixtures of thenoyltrifluoroacetone (HTTA) and neutral organophosphates (S) from the same aqueous medium. This effect decreased as S was changed from a phosphine oxide, through phosphonate, to the neutral alkyl phosphates. Tracer studies showed that the composition of each extracting species is given by the general formula M(TTA)3S2 where M is a trivalent actinide or lanthanide. These species were independent of the diluent used but the extraction coefficients of the metal ions decreased by a factor of 104 from cyclohexane to chloroform. At a constant pH the extraction of americium and cerium was inversely proportional to DTPA concentration in the region 10−3 −10−1M. At lower DTPA concentrations the cerium dependence decreased rapidly while the americium increased until at 10−4M concentration of DTPA the extraction order was reversed. When the DTPA concentration was constant the separation of cerium from americium increased with increasing pH, reaching a constant maximum at pH 2·6 and above.
Publication Year: 1973
Publication Date: 1973-07-01
Language: en
Type: article
Indexed In: ['crossref']
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Cited By Count: 9
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