repeat stan 7, extract 90 . -w . . Yttrium from che 5% YDERP with two 50 ml volumes of 3N HNO,. Shake 2 minutes for each extracticn and combine the 3N HNO, solutions in a 250 ml beaker, 10. evaporate the 3N HNO, solution to a volume of a few ml and quantitatively transfer to a 50 ml centrifuge tube with several small volumes of distilled 4,0, ll. place centrifuge tube in a not water bath and adjust pH tc 8-10 with NH,OH to precipitate yttrium hydroxide, 12. centrifuge and decant supernatant liquid, 13. wasn precipitate with 10 ml distilted H.0, centrifuge and discard wash, 2 14. dissolve precipitate in 1:1 HCl (1-2 ml), slurry and >ring volume to 25 ml with distilled 4,0; 15. add 2-3 ml saturated oxalic acid, 0.5 - 1 ml NH, OH, stir and digest at 85-90°C for 1 hour, 16. filter through preweighed glass fibre filter and dry at 100-110° for 10 minutes, . . . . . 17. weigh sample and paper and determine gravimetric yield of 18. mount and beta count, 19. . - 2, 90 ‘ count again in 24-48 hours to verify 9 Yttrium decay. Counting Equipment 90 oe 4 aa pe Strontium is counted as its daugnter product coincidence low background beta counter. Ie Yetrium pe ‘\ . Yttrium, es . using an anti- The system has an absolute 51% counting efficiency and a’ background range of 1.0 - 1.5 cpm. ll 90 Recovery of the

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