Extraction of carbonate complexes of trivalent transplutonium elements with alkyl pyrocatechols

Extraction of trivalent americium curium, californium, and europium with a technical mixture of mono-and didecyl pyrocatechols (TAP) in different diluents from carbonate solutions is studied. The influence of various factors (pH, K/sub 2/CO/sub 3/, TAP and metal concentration, phase contact time) on the degree of extraction and separation of the elements is clarified. It is shown that the elements concerned are extracted quantitatively by TAP solution in toluene and cyclohexane in the K/sub 2/CO/sub 3/ concentration range 0.25-1.5 M. A difference is noted in the coefficients of americium and curium distribution when they are extracted with TAP from 0.25 M K/sub 2/CO/sub 3/ solution. The separation coefficients of this pair rise with the pH of the carbonate solution. The separation coefficients of this pair rise with the pH of the carbonate solution. The separation can be improved at the stage of reextraction of the elements with a mixture of K/sub 2/CO/sub 3/ and DTPA or EDTA from alkyl pyrocatechol because the americium and curium reextraction rate constants differ widely. The composition of the compounds in the organic phase based on 4-(..cap alpha..,..cap alpha..-dioctylethyl)pyrocatechol (DOP) is studied by /sup 13/C NMR spectroscopy.