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US 3,980,757 AGranted
Process for uranium separation and preparation of UO.sub.4.2NH.sub.3.2HF
AssigneeThe Babcock & Wilcox Company
InventorHalit Z. Dokuzoguz
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AssigneeThe Babcock & Wilcox Company
InventorHalit Z. Dokuzoguz
Estimating the term…
A process for treating the aqueous effluents that are produced in converting gaseous UF.sub.6 (uranium hexafluoride) into solid UO.sub.2 (uranium dioxide) by way of an intermediate (NH.sub.4).sub.4 UO.sub.2 (CO.sub.3) .sub.3 ("AUC" Compound) is disclosed. These effluents, which contain large amounts of NH.sub. 4.sup.+ (ammonium), CO.sub.3.sup.-.sup.- (carbonate), F.sup.- (fluoride), and a small amount of U (uranium), are mixed with H.sub.2 SO.sub.4 (sulfuric acid) in order to expel CO.sub.2 (carbon dioxide) and thereby reduce the carbonate concentration. The uranium is precipitated through treatment with H.sub.2 O.sub.2 (hydrogen peroxide) and the fluoride is easily recovered in the form of CaF.sub.2 (calcium fluoride) by contacting the process liquid with CaO (calcium oxide). The presence of SO.sub.4.sup.-.sup.- (sulfate) in the process liquid during CaO contacting seems to prevent the development of a difficult-to-filter colloid. The process also provides for NH.sub.3 (ammonia) recovery and recycling. Liquids discharged from the process, moreover, are essentially free of environmental pollutants. The waste treatment products, i.e. CO.sub.2, NH.sub.3, and U are economically recovered and recycled back into the UF.sub.6 .fwdarw.UO.sub.2 conversion process. The process, moreover, recovers the uranium as a precipitate in the second stage. This precipitate is a new inorganic chemical compound UO.sub.4.2NH.sub.3.2HF [uranyl peroxide-2-ammonia-2- (hydrogen fluoride)].
A process for producing UO.sub.4.2NH.sub.3.2HF from a uraniferous mixture that is produced in converting uranium hexafluoride into uranium dioxide by way of an intermediate (NH.sub.4).sub.4 UO.sub.2 (CO.sub.3).sub.3 wherein the mixture has a titratable basicity of 2.0 to 2.5 equivalents per liter (eq/l) and a hydronium concentration that corresponds to a pH of about 9.0 to 9.5, and which also contains carbonates, fluorides and ammonium, comprising the steps of adding sulfuric acid to the mixture until the combined mixture has a pH that is between 6.5 to 7, cooling and mixing the combined mixture while said sulfuric acid is being added in order to release the carbonates from the combined mixture until the carbonate concentration in the resulting mixture is reduced to less than 5 g/l, and to leave sulfate ions therein, adding ammonia to the resulting mixture to produce a pH between 8.4 to 9, adding an excess hydrogen peroxide to each liter of the resulting basic mixture to separate said residual basic mixture into a precipitate of UO.sub.4.2NH.sub.3.2HF and an essentially uranium free material that contains said sulfate ions, separating said precipitate from said material as a new uranium and fluoride chemical compound.
UO.sub.4.2NH.sub.3.2HF.
A process for removing a thixotropic fluorine compound from a uraniferous mixture that also contains carbonates and ammonium comprising the steps of adding sulfuric acid to the mixture until the mixture pH is about 6.5 to 7 in order to separate the carbonates, adding hydrogen peroxide to said combined mixture to separate said combined mixture into a precipitated uranium and fluorine chemical compound and a filtrate, and adding calcium oxide to said filtrate to precipitate calcium fluoride and calcium sulfate in the presence of thixotropy inhibiting sulfate ions from said sulfuric acid.
A process for the recovery of uranium, fluoride, NH.sub.3 and CO.sub.2 from a uraniferous mixture that is produced in converting uranium hexafluoride into uranium dioxide by way of an intermediate (NH.sub.4).sub.4 UO.sub.2 (CO.sub.3).sub.3 wherein the mixture has a titratable basicity of 2.0 to 2.5 equivalents per liter (eq/l) and a hydronium concentration that corresponds to a pH of about 9.0 to 9.5, and which also contains carbonates, fluorides and ammonium, comprising the steps of adding sulfuric acid to the mixture until the combined mixture has a pH that is between 6.5 to 7, cooling and mixing the combined mixture while said sulfuric acid is being added in order to release the carbonates from the combined mixture until the carbonate concentration in the resulting mixture is reduced to less than 5 g/l, and to leave sulfate ions therein, adding ammonia to the resulting mixture to produce a pH between 8.5 to 9, adding an excess hydrogen peroxide to each liter of the resulting basic mixture to separate said residual basic mixture into a uranium precipitate and an essentially uranium free material that contains said sulfate ions, separating said uranium free material from the precipitate, adding calcium oxide to said material in which said sulfate ions prevent thixotropy in the resulting mixture in order to precipitate calcium fluoride and calcium sulfate, liberating ammonium and water vapor from said material during the calcium oxide addition, condensing said ammonium and water vapor into aqueous ammonia.
Dependencies are inferred from the claim text.