Improvements in processes for simultaneously purifying and concentrating plutonium solutions

摘要

1,113,237. Plutonium separation. COMMISSARIAT A L'ENERGIE ATOMIQUE. 20 May, 1965 [19 June, 1964], No. 21460/65. Heading G6R. An aqueous solution of plutonium of sulphate content less than 0À2M is concentrated and purified, for example from uranium and fission products, by counterourrent extraction of plutonium with an orgunic phase containing tributyl phosphate, contacting the organic phase with a solution of uranous nitrate to reduce the plutonium to the trivalent state, extracting the plutonium with a solution of hydrazine in nitric acid, and recycling a portion of the aqueous phase to the first extraction together with the original solution; the recycled portion is oxidized to bring the plutonium back to the tetravalent state. The tributyl phosphate may be diluted with dodecane, CCl 4 , or an aromatic oil distillate. The aqueous solution from the re-extraction step is preferably scrubbed with pure organic solvent. The uranous nitrate reducing solution preferably also contains hydrazine. The oxidation may be effected with nitrous vapours, followed by removal of the nitrous vapours by agitation with air. Each countercurrent extraction step may be carried out in a battery of mixing- settling tanks.