DI (2-Ethylhexyl) Isobutyramide (D2EHIBA): A Promising Extractant For The Separation Of Uranium From Macro Concentration Of Thorium

摘要

Branched chain amide, di(2-ethylhexyl)isobutyramide (D2EHIBA) has been found promising for selective extraction of uranium over thorium and a large number of fission products. Six stage mixer settler runs have been carried out employing 0.5M D2EHIBA-dodecane as the extractant. Feed composition during these runs was: [Th] = 200 g/L, [U]= 210 mg/L, [HNO_3] = 4.0M, [HF] = ～0.05M and [Al(NO_3)_3] = ～0.1M maintaining the organic-to-aqueous phase ratio as 1. Final composition of the loaded organic phase was: [U] = ～208 mg/L; [Th] = 180 mg/L and [HNO_3] = 0.44 M. The aqueous EXIT samples contained 6+-1 mg/L U suggesting the need for additional extraction stages. Quantitative stripping of uranium could be achieved employing distilled water as strippant in six stages maintaining organic-to-aqueous phase ratio as 2. Uranium, thorium and nitric acid concentration in the aqueous phase collected after stripping was ～410mg/L, ～360 mg/L and 0.75M respectively. Final purification of U was accomplished by cation exchanger Dowex 50x4.