Liquid Membrane Process for the Selective Recovery of Uranium from Industrial Leach Solutions

Leach liquor of uranium concentrates are generated at Uranium Corporation of India Limited (UCIL), Jaduguda, India. Application of the emulsion liquid membrane (ELM) technique was tested for the efficient recovery of uranium from the leach liquor, in the presence of metal ions such as Fe, Ca, Mg, and Mn. The liquid membrane employed consisted of a diluent (light and heavy paraffin), a surfactant (Span 80), and an extractant (Alamine 336), and sodium carbonate was used as the stripping solution. Initially, the ELM process parameters were optimized by using synthetic leach liquor as the feed phase. The role of the acidic feed-phase pH, which enhances the cotransport of H(+) ions along with uranium inside the emulsion globules, was found to be significant, as it helped in achieving the complete extraction and stripping of uranium. The best optimized parameters were directly used for the separation and concentration of uranium from industrial leach solutions. In one step, in the presence of various metal ions, the selective permeation of uranyl ions through the liquid membrane was observed to be greater than 90%, and the concentration of uranium inside the strip phase was observed to be nearly 7 times higher. Separation factors of uranium with respect to Fe, Mg, Ca, and Mn were experimentally found to be 129, 781, 43, and 1462, respectively, in 12 min. Finally, application of the process in uranium ore processing is demonstrated.