Selective extraction of U(VI) by counter-current liquid-liquid extraction with ,-di(2-ethylhexyl)-2,2-dimethylpropanamide

Ban, Yasutoshi  ; Hotoku, Shinobu ; Morita, Yasuji  

A continuous counter-current extraction experiment for selective extraction of U(VI) using ,-di(2-ethylhexyl)-2,2-dimethylpropanamide (DEHDMPA) as an extractant was carried out with mixer-settler type extractors consisting of a U extraction step, a scrub step, and a U back-extraction step. DEHDMPA selectively extracted U(VI) over Pu(IV), and the decontamination factor against Pu(IV) in the U fraction was 990. Fractional distributions of U(VI) in the U fraction and Pu(IV) in the raffinate were 94.5% and 99.9%, respectively. Numerical simulation for calculating U(VI) and Pu(IV) concentrations in each stage of the mixer-settlers was performed. The calculated values agreed with experimentally measured U(VI) and Pu(IV) concentrations in the U extraction step, and also agreed with experimentally measured U(VI) concentrations in the scrub step.