Ammonium diuranate

ADU [Ammonium diuranate] A process for converting uranium hexafluoride into uranium dioxide, for use as a nuclear reactor fuel. The hexafluoride is hydrolyzed in water ... 

The amine (B) is a proprietary mixture of C8 and C10 primary alkylamines dissolved in kerosene. The uranium is stripped from the organic solution with an alkaline stripping solution and precipitated as ammonium diuranate. See also Dapex. 

Uranium is best known as a fuel for nuclear power plants. To prepare this fuel, uranium ores are processed to extract and enrich the uranium. The process begins by mining uranium-rich ores and then crushing the rock. The ore is mixed with water and thickened to form a slurry. The slurry is treated with sulfuric acid and the product reacted with amines in a series of reactions to give ammonium diuranate, (NH4)2U20 . Ammonium diuranate is heated to yield an enriched uranium oxide solid known as yellow cake. Yellow cake contains from 70—90% U3Og in the form of a mixture of U02 and U03. The yellow cake is then shipped to a conversion plant where it can be enriched. 

Enriched UF6 is processed into U02 powder at fuel fabrication facilities using one of several methods. In one process uranium hexafluoride is vaporized and then absorbed by water to produce uranyl fluoride, U02F2, solution. Ammonium hydroxide is added to this solution and ammonium diuranate is precipitated. Ammonium diuranate is dried, reduced, and milled to make uranium dioxide powder. The powder is pressed into fuel pellets for nuclear reactors. 

Ammonium Diuranate. Pour 5 ml of a uranyl nitrate solution into a 50-ml beaker. Heat the solution to 80 °C and add several drops of a methyl orange solution to it. What causes the colour of the indicator to change Carefully pour in a 10% ammonia solution containing no carbon dioxide dropwise until the colour of the indicator changes. What substance precipitates Write the equation of the reaction. 

How can the formed complex compound be decomposed What substances prevent the precipitation of ammonium diuranate ... 

Figure 16.4 Ammonium diuranate (yellowcake) after solvent extraction. (Photo courtesy of UIC.) (Figure also appears in color figure section.)...

Ammonium hydroxide is added to the uranyl fluoride solution to quantitatively precipitate ammonium diuranate... 

After the extraction and washing of the aqueous phase by an equal volume of benzene, U Is ppted. as ammonium diuranate by addition of HE4QH. The ppt. Is centrifuged. 

Ammonia solution yellow precipitate of ammonium diuranate, insoluble in excess of the reagent, but soluble in ammonium carbonate or sodium carbonate, forming the tricarbonatouranylate(VI) ion ... 

Addition of aqueous NH3 to U02(N03)2 solutions affords the so-called ammonium diuranate. This is mainly a hydrated uranyl hydroxide containing NHJ. Below 580°C it gives U03 and above, U3Og. 

In animal studies, rats exposed to dusts of ammonium diuranate containing 6.8 mg U/m for 6 hours a day, 5 days per week for 30 days developed a rise in neutrophils, a decrease in lymphocytes, a moderate fall in the white blood cell count, and a rise in the number of eosinophils (Dygert 1949b). Rats exposed to airborne uranyl nitrate hexahydrate containing 9.5 mg U/m 8 hours a day, 5 days a week for... 

In other intermediate-duration studies, no effects were seen on the Uver of dogs given oral doses of 9,393 mg U/kg/day as uranyl nitrate hexahydrate or 191 mg U/kg/day as ammonium diuranate for 30 days (Maynard and Hodge 1949). Similarly, no effects were seen on the liver of rats given oral doses of 8,769 mg U/kg/day as uranium tetrachloride, 11,033 mg U/kg/day as triuranium peroxide,... 

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