GB786883A - Method of purifying uranium - Google Patents

Abstract

In the production of uranium having an extremely low boron content, uranium metal preferably obtained electrolytically is converted to an oxide and the oxide heated to a temperature above 1000 DEG C. for sufficient time for the boron impurity to volatilize. The oxide is thereafter converted to the metal having a boron impurity as low as 0.5 ppm. The initial uranium may be obtained for example by the electrolysis of potassium uranous fluoride which may be prepared by a photochemical reduction, preferably using sunlight of a solution containing a uranium salt such as the nitrate, potassium fluoride, hydrofluoric acid and a reducing agent such as formic acid or sucrose. Such potassium uranous fluoride precipitate is removed, washed, dried and introduced into a bath of fused sodium and calcium chlorides in a graphite crucible with a molybdenum cathode. On electrolysis at a temperature of about 900 DEG C. boron contaminated uranium metal collects on the cathode which is removed, crushed and ground and thereafter burnt to form an oxide of uranium. The oxide is then heated to a temperature of about 1200 DEG C. whereby the boron is volatilized and the thus purified uranium oxide may be converted to the nitrate and uranium metal again produced electrolytically as before.