Recovery of uranium from oxalate solutions using hollow fibre renewable liquid membrane

Certain favorable qualities of the precipitate and amenability to recycle filtrate solution are important factors to choose oxalate route of reconversion for nuclear material. Oxalate salt of U(VI) is highly soluble in aqueous nitrate solutions hence conversion of U(VI) to U(IV) is an essential step, prior to its precipitation by oxalate ions. In addition to the solubility parameter, conversion ratio of U(VI) to U(IV) is also a governing factor controlling uranium losses in the aqueous filtrate. Usually ~ 100 ppm of uranium losses is observed in oxalate filtrate solutions which also contain 0.05 to 0.1 M oxalate ions. Direct recovery of uranium from this filtrate solution under laboratory scale operation is more economical. Hollow fibre renewable liquid membrane (HFRLM) is reported to be highly efficient and compact hydrometallurgical process to treat low value waste solutions. In present communication recovery of uranium from oxalate solutions using HFRLM containing tri-octyl phosphine oxide (TOPO) as ion carrier is reported. The effect of feed volume, concentration of oxalate ions and H⁺ ions on the recovery process is studied