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