RECOVERY OF Np-237 BY AN OXIDATION-REDUCTION FLUORIDE PRECIPITATION METHOD

摘要

Several hundred grams of Np-237 in nitric acid solution was ~95％ recovered as NpO2 of >99.5％ purity. The remaining 5％ was recovered as a nitric acid solution of 99.95％ purity. The neptunium was oxidized to the soluble +6 state with sodium bromate, and Pu(IV), thorium, and other impurities in the solution were precipitated as fluorides. The neptunium was then reduced to Np(IV) with sulfur dioxide and pre¬cipitated as KNpF5, dissolved in nitric acid, precipitated as neptunium oxalate, and calcined to the oxide. The recovered material balance was 99.91％ with a process loss of 0.09％.