Development of a method for recovery of 233{sup left}U from thorium oxalate cake in reconversion step of reprocessing of irradiated thorium rods

摘要

A method is developed for the selective leaching of 233{sup left}U from a thorium oxalate cake. The leaching capacity of ammonium carbonate and nitric acid have been investigated showing that (NH{sup left}4) {sup left}2CO{sup left}3 leads to higher recovery. The maximum leaching efficiency is obtained using 0.5% ammonium carbonate, with a minimal thorium pick-up. A uranium recovery of 94% is obtained after three consecutive contact experiments in carbonate media, with minimal thorium uptake in the leachate. This process was applied to an actual plant stream, allowing the reduction of the 233{sup left}U α-activity from 5.64 to 0.3 μCi/g of thorium oxalate cake.