The development and application of a process for the recovery of over 100g of protactinum-231 from a uranium refinery waste material

Abstract

This paper describes the development of a process for the recovery of protactinium-231 and uranium from a residue known as ethereal sludge that was produced during uranium refining at the U.K.A.E.A. Springfields Works. The process is suitable for operation on a large scale and involves the following stages: 1. 1. Leaching protactinium and uranium from the sludge with cold 4N HNO 3 in the presence of fluoride. 2. 2. Recovering uranium by extraction into 20 per cent TBP-OK. 3. 3. Adding aluminium chloride to the aqueous raffinate and separating a precipitate that carries protactinium. 4. 4. Treating the precipitate with cold NaOH solution and then dissolving it in concentrated hydrochloric acid. 5. 5. Recovering protactinium by extraction into di-isobutylketone. In laboratory operations the process proved capable of recovering 98–99 per cent of the uranium and 65–70 per cent of the protactinium originally present in the ethereal sludge. The above process was successfully applied to the recovery of over 100 g of protactinium and of nearly 12 tons of uranium with an efficiency of 63 per cent for protactinium and 99·4 per cent for uranium.