Chloride anion exchange coprocessing for recovery of plutonium from pyrochemical residues and Cs2PuCl6 filtrate

摘要

Continuing studies of plutonium recovery from direct oxide reduction (DOR) and electrorefining (ER) pyrochemical process residues show that chloride anion exchange coprocessing is useful and effective. Coprocessing utilizes DOR residue salt as a reagent to supply the bulk of chloride ion needed for the chloride anion exchange process and to improve ER residue salt solubility. ER residue salt and ER scrapeout can be successfully treated, either alone or together, using coprocessing. In addition, chloride anion exchange at 2.0M acidity results in improved process performance by greatly reducing disproportionation of plutonium(IV), eliminating restrictions on oxidation time compared to operation at 1.0M acidity. Laboratory-scale experiments show that below-discard effluent plutonium losses are obtained. Resin capacity was 30 g Pu/(ell) or greater. Furthermore, it is feasible to perform chloride anion exchange recovery of plutonium from filtrate resulting from precipitation of dicesium hexachloroplutonate (Cs(sub 2)PuCl(sub 6), an oxidant salt to be used in the molten salt extraction process) and integration of its preparation with recovery of DOR salts. 10 refs., 9 figs., 10 tabs.