Mutual Separation of Yttrium-91 and Promethium-147 by Countercurrent Solvent Extraction in Pulse Column

Continuous solvent extraction was proved satisfactory in separating Y91 from Pm147, using synthetic mixtures of the pair of nuclides. The separation was conducted in a compound perforated plate pulse column using 10% di(2-ethyl hexyl) phosphoric acid in toluene against an aqueous solution of HNO3. One column volume change per hour was realized by appropriate choice of flow rates. Pulse frequency was maintained at 50 cycles per minute and pulse amplitude at 1 cm. The Pm: Y ratio in the feed was varied from 0.08 to 135. Pm in excess of 99% and Y in excess of 97% purity were obtained. Steady state was reached in 12 hours. Finally, the approach to steady state was the same for any one component in all runs conducted, but was much slower than that predicted by calculations reported in the literature for discrete stages.