Supercritical fluid extraction of uranium from unsintered/sintered oxides samples using tri-n-butyl phosphate and N,N-dihexyloctanamide

Direct extraction of different uranium oxide samples (unsintered UO3 and U3O8 and sintered UO2) was carried out using supercritical carbon dioxide modified with methanol solutions of extractants (30% v/v) such as tri-n-butyl phosphate (TBP) and/or, N-dihexyloctanamide (DHOA) in dynamic as well as static modes of extraction. Whereas near quantitative (> 95%) uranium extraction was observed in static mode, only partial extraction was observed in dynamic mode of extraction. This method holds promise for the direct assay of uranium from ores/different oxide samples without the tedious chemical methods. (author)