Flowsheet for the recovery and purification of 63Ni

The production of large quantities of high specific activity (>10 Ci/g)63Ni requires both a highly enriched 62Ni target and a long irradiation period at high neutron flux. Trace impurities in the nickel and associated target materials are also activated and account for a significant fraction of the discharged activity, and essentially all of the gamma activity. While most of these undesirable activation products can be removed as chloride complexes during anion exchange, chromium, present as 51Cr, and scandium, present as 46Sc, are exceptions and require additional processing to achieve the desired purity. Scandium is readily removed during cation exchange, while the removal of chromium requires careful control of conditions during solvent extraction with tri-n-octylphosphine oxide. Optimized flow-sheets are discussed based upon the current development and production experience. (orig.)