Carrier-free separation of228Ac from aged thorium nitrate

Abstract

Reagents: Unless stated otherwise, all reagents used were of analytical grade. The reagents required are: fuming nitric acid, barium nitrate (a carrier), cupferron (5% aqueous solution), chloroform, aqueous ammonia, ammonium acetate (a buffer), lead nitrate (a carrier), hydrogen sulphide, and dithizone (for the detection of lead). Apparatus: Separatory funnels, beakers, laboratory centrifuge, flask shaker, Kipp's apparatus, and GM beta-counting equipment. Procedure: 1. Dissolve 5 g of thorium nitrate in 60-70 % nitric acid. Add 5 mg of barium carrier as a barium nitrate solution (5 mg/ml). 2. Precipitate barium(radium) nitrate with fuming nitric acid, adding a little at a time followed by vigorous stirring. The reaction vessel should be kept immersed in crushed ice. Separate the precipitate by centrifugation, and dissolve in a very small quantity of distilled water. Set aside for a couple of days to let 22SAc grow in. 3. Treat the acid barium(radium) nitrate solution with 3 ml of a 5 % aqueous solution of cupferron and 5 ml of chloroform. Shake mechanically for 5 10 min. Separate the organic phase containing thorium and discard it. 4. Adjust the pH of the aqueous phase to 6 with aqueous ammonia. Add 10 ml of 0.9M ammonium acetate, shake, add 3 ml of aqueous cupferron (5 % solution)