Uranium tetra-fluoride

The static bed dryway process for the production of uranium tetra-fluoride involves less advanced chemical engineering techniques than, for example, fluidization. With careful design and correctly optimized operating conditions, it has been difficult to supplant, however, on purely economic grounds. Many thousands of tons of uranium tetrafluoride have been produced by this method since the Second World War in the United Kingdom and the United States alone. 

Uranium enrichment and fuel fabrication For light-water-moderated and light-water-cooled reactors (LWRs) and for advanced gas-cooled graphite moderated reactors (AGRs), the uranium processed at the mills needs to be enriched in the hssile isotope Enrichments of 2-5% are required. Before the enrichment, the uranium oxide (UsOg) must be converted to uranium tetra-fluoride (UF4) and then to uranium hexa-fluoride (UFg). 

Rapid Release of Volatile Fission Products from Solid Uranium Tetra-fluoride. Inorg. Nucl. Chem. Lett. , No. 5, 519 (1973). 26 2402... 

Preparation of fluorides aluminum trifluoride, uranium tetra- and hexafluorides... 

Calcination of aluminum hydroxide to alumina Preparation of aluminum sulfate from bauxite Preparation of fluorides aluminum trifluoride, uranium tetra- and hexafluorides... 

Ammonium uranyl carbonate (AUC) process This process was developed in the 1960 s in the Federal Republic of Germany. It comprises the simultaneous feeding of uranium(Vl) fluoride, carbon dioxide and ammonia into an aqueous ammonium carbonate solution at 70°C, whereupon tetra-ammonium tricarbonato-dioxo-uranate (ammonium uranyl carbonate) precipitates out ... 

Uranium Hexafluoride, Uranic Fluoride, UFg, is the only known compound of hexavalent uranium (with the possible exception of the boride in which the condition of the uranium is not established) which does not contain oxygen. It was first prepared by Ruff and Heinzel-mann by the action of fluorine on uranium pentachloride at —40° C. The action proceed.s as already described (see equation above), and the volatile hexafluoride is distilled off from the tetrafiuoride. The penta-ehloride, Avhen acted upon by dry hydrogen fluoride, yields a compound, UF5.a HF, which breaks up on distillation into the tetra- and hexafluorides, but this method of preparation is less convenient than the preceding one owing to the difficulty of separating the hexafluoride from hydrogen fluoride. Uranium carbide reacts with fluorine in presence of a little chlorine at —70° C., vith formation of the hexafluoride. 

The hexafluorouranate products are all air-sensitive, pale blue-green powders. The reaction of [UFg] with water produces [UFs] and [U02F4] whose presence in the product may be determined by the visible-near-infrared spectrum in acetonitrile. The characteristic fundamental V3 mode of [UFe] is found at 525 cm" in the infrared spectrum of the salts. Reactions of tetra-alkylammonium fluorides with uranium pentafluoride in acetonitrile yield the corresponding [UF ]" salts, but these salts were found to be unstable under vacuum after removal of acetonitrile. They can be prepared less conveniently in HF, however. The uranium in NaUFe is six oordinate in solution and in the solid state, whereas in KUFj the uranium is six-coordinate in solution and eight-coordinate in the solid state. The exact geometry of the isolated... 

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