PALLADIUM SEPARATION FROM NITRATE SOLUTION BY MEANS OF ANION-EXCHANGER RESINS

摘要

The prospects for development of the fuel reprocessing industry are intimately associated with many factors including economic profitability of fissile material recycling and necessity of safe management and removal from the biosphere of all generated radioactive wastes. At the same time it's only during spent fuel reprocessing there is opportunity of separation of individual radionuclides for their further usage (cesium, strontium, noble metals, technetium, tritium, krypton). Here again, in our opinion, the interest the metals of platinum group recovery is represented. As the most favorable feed solutions for platinum metals recovery during spent fuel reprocessing, it's possible to use the solutions formed at the partitioning stage after first extraction cycle. Just on this account the further studies on effective technology of palladium and other platinum metals recovery should be carried out concurrently with the resolution of HLW partitioning problem. The object of present work was to estimate capacitive characteristics of different anion-exchangers in respect of palladium so as to elucidate the possibilities of their uses for palladium recovery from spent fuel. The second object of the work was the testing of sorption technique of palladium recovery from raffinate of Purex process in the "hot" cells. The characteristics of exchange capacity for anion-exchangers involving tertiary amino groups (of Dowex and Amberlite types) are presented. At the final stage the sorption technology for palladium recovery from real solutions generated during NPP's spent fuel reprocessing have been tested. When using the sorption technique (anion-exchanger VP1-AP), palladium transfer in the desorbate was about 90% and after additional purification through precipitating technique the deposition of palladium black was produced. The activity of this product didn't exceed 0.8 mCi/g Pd, total purification factor being 1.9×10{sup}4.