Extraction of Y, Ce and La from uranium leaching solution of Yazd Saghand area, Iran - a case study

'Ion exchange method is best suited for extraction of U, Th and REE from acid-leach extract of uranium ores. The present note provides laboratory-scale methodology for optimum recovery of Y, Ce and La from acid-leach extract of low-grade uranium ores of Saghand area, Yazd province, Iran. The uranium ore was subjected to acid leaching and the resultant acid-Ieach extract was analyzed by XRF and ICP (MS) to determine the initial concentration of Y, Ce and La. Recovery of Y, Ce and La from the acid-leach extract involved (1) soaking a selected resin (0.5 cc) kept in the ion-exchange column with acid-leach extract and allowing the extract to be in contact with the resin for a specific duration of time. (2) draining away the heavy elements. (e.g. U, Th, Zr, Fe, Al, Mg etc) settled at the bottom portion of the ion exchange column along with REE-impoverished acid-leach extract, (3) chemical analysis of the REE-enriched resin to determine the amount of absorbed Y,Ce and La, (4) soaking the REE-enriched resin with eluting (washing) solution (sodium acetate) and allowing the solution to be in contact with the REE-enriched resin for a specific period of time, (5) draining and collection of REE-enriched eluting solution, and (6) chemical analysis of the REE-enriched eluting solution to estimate the extent of recovery of Y, Ce and La. Several ion-exchange trial runs were conducted using (1) different types of resins, (2) different volumes of resin, and (3) acid-leach extract and eluting solution having different pH values. Trial runs were also carried out at different time durations of contact of the REE-enriched resin with eluting solution. The trial runs indicated that among the five types of resins used, the Dowex 50WX8 (Hz) (100-200 mesh) is best suited for optimum recovery of Y, Ce and La. 0.5 cc of resin is found to be sufficient to achieve the best results. Trial runs carried out with acid-leach extract having pH value around 1.1 and eluting solution having pH value around 0.7 provided maximum yield of Y, Ce and La. Optimum recovery of Y, Ce and La from REE-enriched resin was achieved when the time duration of contact of the REE-enriched resin with the eluting solution was maintained at 30 minutes. (author)