Westinghouse Electric Corporation

United States Steel Corporation

Wyoming Mineral Corporation

Peter T Chiang

Edward Jean Lahoda

Herbert A Burgman

Erich W Tiepel

A solvent extraction-exchange process for the enrichment of either the zirconium 90 isotope component or the zirconium 91-96 isotope component of an aqueous feed stream containing both components is described. An aqueous feed stream of zirconium complexes such as that from a thiocyanate separation process is contacted with an organic solvent to preferentially extract one of the isotope components, resulting in an aqueous raffinate enriched in the other isotope component. The organic phase is further contacted with an aqueous phase enriched in said one isotope component to exchange the other isotope component from the organic phase with the one isotope component in the aqueous phase and produce a further enriched organic phase. The one isotope component in the further enriched organic phase is then stripped with an aqueous acidic strip medium, and zirconium enriched in said one isotope component separated therefrom.

Process for separating zirconium isotopes

A continuous process is disclosed for precipitating uranium from an aqueous solution formed by the hydrolysis of uranium hexafluoride gas. Undersized ammonium diuranate particles are formed in a first container by mixing the aqueous solution and an ammonium hydroxide solution containing about 10 to about 30% by weight ammonium. The ratio of the two solutions should be such that there are about 20 to about 30 moles of ammonium per mole of uranium. The temperature is maintained at about 30.degree. to about 50.degree. C. and the residence time in the first container is about 14 to about 57 seconds. The slurry is then transported to a second container for further particle growth where it is agitated at a temperature of about 20.degree. to 40.degree. C. for a residence time of about 2 to about 9 minutes. The resulting ammonium diuranate precipitate has a surface area of about 10 to about 20 meters squared per gram. The precipitate can then be calcined and pressed into pellets.

Process for making high quality nuclear fuel grade ammonium diuranate

A process is disclosed for improving the quality of an ammonium diuranate (ADU) precipitate. Ammonium hydroxide is added to a solution of uranyl fluoride in the presence of a polymer such as polyacrylic acid, polyacrylonitrile, or polyacrylamide. The presence of the polymer reduces the particle size of the precipitate and increases its settling rate. A reduced particle size provides an ADU powder which is suitable for nuclear fuel fabrication and an increased settling rate enhances the dewatering operation of the ADU slurry.

Method of precipitating ADU

In uranium recovery by solvent extraction processes, uranium is separated from iron in an organic extract by stripping the extract with a dilute aqueous solution containing carbonate ions, hydroxyl ions, and ammonium or alkali metal ions. The iron precipitates during stripping as Fe.sub.2 O.sub.3.nH.sub.2 O which is filtered off. The uranium is then precipitated from the filtrate as UO.sub.3.2H.sub.2 O by steam stripping or as ammonium diuranate by lowering the pH to about 2 to decompose the carbonate then raising it with ammonia or ammonium hydroxide to about 7.

Method of separating iron from uranium

Wet-process phosphoric acid is partially purified by extraction with an organic solvent followed by scrubbing with a portion of the aqueous phosphoric acid from a water-stripping unit, then water-stripping and base-stripping. At the water-stripping stage, all the remaining impurities and approximately two-thirds of the P.sub.2 O.sub.5 are transferred from the organic to the aqueous phase, which renders the other one-third P.sub.2 O.sub.5, subsequently recovered by base-stripping, essentially free of impurities. The bulk of the aqueous phosphoric acid from the water-stripping is purified further by precipitating the impurities with an alkali metal hydroxide or carbonate. The precipitate is filtered off and the filtrate used for base-stripping. The resulting aqueous solution from base-stripping is adjusted to a desired alkali metal-to-phosphate ratio and used for manufacture of high purity alkali metal phosphate in general and particularly sodium tripolyphosphate.

Growing community of inventors

Monroeville, PA, United States of America

Peter T Chiang