Improvements in or relating to the production of uranium values

摘要

Uranium values are separated from impurities by feeding an aqueous acidified solution, for example nitric acid solution, containing uranium values and impurities to a chromatographic column of alyophobic, organic polymer in microporous form, preferably poly (trifluoromonochloroethylene) powder, supporting an organic solvent which retains uranium such as tributyl phosphate, tri-iso-oclytamine, or tri-n-octylamine. The column is washed with acid to remove impurities, and uranium eluted with water. The process may be effected continuously by moving the columns of chromatographic material through a series of chambers, different steps in the process being effected in different chambers. The process may be used to separate uranium from its daughter products, radium, bismuth and polonium, and for example, from chromium, copper, aluminium, nickel, vanadium, calcium, iron, molybdenum, tungsten, sodium, potassium, fluoride, phosphate, sulphate, and chloride, and from concentrated solutions of citric acid. Uranium may also be separated from cerium; cerium IV is retained on the column after washing with nitric acid and is subsequently eluted with water, but can be separated if the cerium is first reduced to cerium III by passing sulphur dioxide through the aqueous feed solution. Plutonium and thorium may be separated from uranium by using hydrochloric instead of nitric acid, and reducing either the plutonium to the trivalent state with, for example, hydroxylamine, or the uranium to the quadrivalent state, before the solution is fed to the column. If tri-iso-octylamine or tri-n-octylamine is used as the organic solvent, sulphuric acid may replace hydrochloric acid or nitric acid. In the example polytrifluoromonochloroethylene) is ground in a microhammer mill and the powder passing a 100 B.S.S. mesh and retained by 200 B.S.S. mesh collected. A column of 25 grams of the powder, and 25 mls tributyl phosphate as a slurry in 5,5 M nitric acid is prepared, and used to separate uranium from 20 mls. of 5,5 M nitric acid containing 1 gram uranium and 1 gram ferric chloride. The column is washed with 5,5 M nitric acid, and the uranium eluted with water. The column is reactivated by washing with 5,5 M nitric acid.