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U S Pat 3 743 695 1973 Jul; :
In the elmex process for recovering u from h2so4 leach solutions by sorption on a strong base ion exchange resin, elution therefrom with h2so4, recovering u from the aqueous acid by solvent extraction with an organic solution, and chemical precipitation, large solution volumes and long retention times are avoided by a more efficient process in which many stages of elution and solvent extraction are coupled together in pairs. The loaded resin is eluted with acid in approximately 5 downward stages in one direction, and from the aqueous acid eluant u is extracted in 5 downward stages in the opposite direction by an amine solution in kerosine. When fully loaded with all the u, the organic solution is scrubbed with h2o and stripped by an aqueous na2co3 solution from which u can be precipitated, and the organic amine solution is recycled. The acid eluate is circulated separately between the elution stages and the extraction stages, with as many separate circuits as there are stages. The acid eluate, which is consecutively loaded and stripped at each stage-circuit, is circulated approximately 10 times as fast as the resin (ed: as this process involves solvent extraction and not ion exchange, amine is probably meant) or the aqueous stripping solution.
U.S. Pat. 3,743,695; July 3, 1973; Chem. Abstr. 79:95,225V
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