Enrichment of 51Cr through Szilard-Chalmers effect

Enrichment of 51Cr has been made by recoil enrichment using potassium chromate as the target material. Irradiation of four days at a neutron flux of 2x1013nxcm-2xs-1 in the core of PARR, followed by a chemical separation using a new liquid-anion exchanger, diphenyl-2-pyridylmethane (0.1 M in chloroform) gives a product of high specific activity (> 30 Ci per gram), suitable for medical diagnostic applications. The chemical procedure is as follows. The irradiated sample (10 g) of the target material (K2CrO4) was dissolved in 20 cm3 of 4 M hydrochloric acid, transferred to a separatory funnel and equilibrated with 0.1 M solution of DPPM in chloroform. Feed/organic volume ratios were 1.5/dm3, there were four equilibrations and all the foregoing contact times were 5 min each. Each time chloroform solution of the substituted pyridine was drained out from the separatory funnel. After equilibrations the aqueous phase was collected, dried and freed from the organic matter with nitric acid and hydrogen peroxide. Chromium(III) was then oxidized to Cr(VI) in alkaline media and the pH value was adjusted. (T.G.)