Plutonium-contaminated ion exchange resin treatment - by oxidn. with silver ions in divided electrolysis cell to achieve high plutonium recovery

摘要

Treatment of Pu-contaminated ion exchange resins involves subjecting the resins, suspended in nitric soln., to oxidn. by Ag2+ ions continuously regenerated by electrolysis, at 40-80 deg.C to destroy the resins and dissolve the Pu, in an electrolysis cell divided by a porous wall into anodic and cathodic compartments. The anodic compartment contains an anode and the resins, suspended in an aq. soln. contg. 3-7 mol/l. nitric acid and 0.05-0.15 mol/l. Ag, and the cathodic compartment contains a cathode and a 7-10 N nitric acid soln. Throughout the electrolysis, 8-12 N nitric acid soln. is introduced into the cathodic compartment and the acidity of the aq. nitric soln. in the anodic compartment is maintained at 3-7 mol/l. by addn. of a weak base. Air is bubbled into the cathodic compartment to convert nitrous acid back into nitric acid. The weak base is CaCO3. Electrolysis is carried out at 10-30 A, while introducing 8-12 N nitric acid into the cathodic compartment at 60-80 ml/hr. During part of the electrolysis time, resin and Ag ions are introduced into the anodic compartment to maintain the resin and Ag ion concns. constant at 100 g/l. and 0.1 mol/l. respectively in the nitric soln. which contains 5 mol/l. HNO3. ADVANTAGE - The process gives Pu recoveries greater than 96% and completely destroys the resins.