Uranium hexafluoride production

Manufacturers. Besides manufacturers in the United States, commercial fluorine plants are operating in Canada, France, Germany, Italy, Japan, and the United Kingdom (see Table 5). Fluorine is also produced in the Commonwealth of Independent States (former Soviet Union) however, details regarding its manufacture, production volumes, etc, are regarded as secret information. The total commercial production capacity of fluorine in the United States and Canada is estimated at over 5000 t/yr, of which 70—80% is devoted to uranium hexafluoride production. Most of the gas is used in captive uranium-processing operations. 

Uranium hexafluoride production Production of organic chemicals 11/15/00 (05/01) (05/02) ... 

We also developed a number of other useful new fluorinating reagents. They ineluded a convenient in situ form of sulfur tetrafluoride in pyridinium polyhydrogen fluoride, selenium tetrafluoride, and ey-anurie fluoride. We introdueed uranium hexafluoride (UFg), depleted from the U-235 isotope, which is an abundant by-product of enrichment plants, as an effective fluorinating agent. 

Fluorine was first produced commercially ca 50 years after its discovery. In the intervening period, fluorine chemistry was restricted to the development of various types of electrolytic cells on a laboratory scale. In World War 11, the demand for uranium hexafluoride [7783-81-5] UF, in the United States and United Kingdom, and chlorine trifluoride [7790-91 -2J, CIF, in Germany, led to the development of commercial fluorine-generating cells. The main use of fluorine in the 1990s is in the production of UF for the nuclear power industry (see Nuclearreactors). However, its use in the preparation of some specialty products and in the surface treatment of polymers is growing. 

Elemental fluorine is used captively by most manufacturers for the production of various inorganic fluorides (Table 5). The market for gaseous fluorine is small, but growing. The main use of fluorine is in the manufacture of uranium hexafluoride, UF, by... 

Uranium hexafluoride [7783-81-5], UF, is an extremely corrosive, colorless, crystalline soHd, which sublimes with ease at room temperature and atmospheric pressure. The complex can be obtained by multiple routes, ie, fluorination of UF [10049-14-6] with F2, oxidation of UF with O2, or fluorination of UO [1344-58-7] by F2. The hexafluoride is monomeric in nature having an octahedral geometry. UF is soluble in H2O, CCl and other chlorinated hydrocarbons, is insoluble in CS2, and decomposes in alcohols and ethers. The importance of UF in isotopic enrichment and the subsequent apphcations of uranium metal cannot be overstated. The U.S. government has approximately 500,000 t of UF stockpiled for enrichment or quick conversion into nuclear weapons had the need arisen (57). With the change in pohtical tides and the downsizing of the nation s nuclear arsenal, debates over releasing the stockpiles for use in the production of fuel for civiUan nuclear reactors continue. 

Fluorine. Fluorine is the most reactive product of all electrochemical processes (63). It was first prepared in 1886, but important quantities of fluorine were not produced until the early 1940s. Fluorine was required for the production of uranium hexafluoride [7783-81 -5] UF, necessary for the enrichment of U (see DIFFUSION SEPARATION METHODS). The Manhattan Project in the United States and the Tube Alloy project in England contained parallel developments of electrolytic cells for fluorine production (63). The principal use of fluorine continues to be the production of UF from UF. ... 

Development efforts in the nuclear industry are focusing on the fuel cycle (Figure 6.12). The front end of the cycle includes mining, milling, and conversion of ore to uranium hexafluoride enrichment of the uranium-235 isotope conversion of the enriched product to uranium oxides and fabrication into reactor fuel elements. Because there is at present a moratorium on reprocessing spent fuel, the back end of the cycle consists only of management and disposal of spent fuel. 

Uranium Hexafluoride (Uranyl hexafluoride). UF6 mw 352.02 colorless, deliq monocl crysts mp 64.5—64.8° bp, subl at 56.2° d 4.68g/cc at 21°. Sol in liq Br, Cl2, C tetrachloride, sym-tetrachlorethane and fluorocarbons. Reacts with extreme violence with benz, ethanol, toluene, w or xylene. Prepn is by reaction of dried, powdered U308 with F gas above 600°. Product purification is by vac sublimation in a quartz appar. The vapor behaves as a nearly perfect gas. The compd has a AHf of 2197.7 1,8KJ/mole. It is used in the gaseous diffusion process for the sepn of U isotopes Refs 1) Gmelin, Syst Nr 55 (1940), 124-31 2) G. Brauer, Handbook of Preparative Inorganic Chemistry , Academic Press, NY (1963), 262 3) CondChemDict (1977), 904-05... 

Fluorine is also used for the manufacture of sulfur hexafluoride (SF6) for high-voltage insulation and for uranium hexafluoride. Fluorine is used directly or combined with higher metals (cobalt, silver, cerium, etc.) and halogens (chlorine and bromine) for organic fluorinations and the growing production of fluorocarbons. 

Hexavalent. Uranium hexafluoride, UFe, is one of the best-studied uranium compounds in existence due to its importance for uranium isotope separation and large-scale production ( 70 000 tons per year). All of the actinide hexafluorides are extremely corrosive white (U), orange (Np), or dark brown (Pu) crystalline solids, which sublime with ease at room temperature and atmospheric pressure. The synthetic routes into the hexafluorides are given in equation (13). The volatility of the hexafluorides increases in the order Pu < Np < U in the liquid state and Pu < U < Np in the solid state. UFe is soluble in H2O, CCI4, and other chlorinated hydrocarbons, is insoluble in CS2, and decomposes in alcohols and ethers. The oxidative power of the actinide hexafluorides are in line with the transition metal hexafluorides and the order of reactivity is as follows PuFg > NpFg > UFg > MoFe > WFe. The UFe molecule can also react with metal fluorides to form UF7 and UFg. The same reactivity is not observed for the Np and Pu analogs. 

Leach LJ, Gelein RM, Panner BJ, et al. 1984. The acute toxicity of the hydrolysis products of uranium hexafluoride (UE6) when inhaled by the rat and guinea pig. Pinal report. ISS K/SUB-81-9039-3. NTIS... 

Morrow PE, Leach LJ, Smith FA, et al. 1982b. Metabolic fate and evaluation of injury in rats and dogs following exposure to the hydrolysis products of uranium hexafluoride. Implications for a bioassay program related to potential releases of uranium hexafluoride. Govt Rep Announce Ind, Issue 11. NTIS/NUREG/CR-2268. 

Albert, H., 1958, Design of a gaseous diffusion uranium hexafluoride isotopic concentration experimental line, in Proc. 2nd U.N. Int Conf. on Peaceful Uses of Atomic Energy 4 (Production of Nuclear Materials and Isotopes), 412. 

Uranium Tetrafluoride, Uranous Fluoride, UF, is the chief product obtained when the metal is acted upon by fluorine. It may be prepared by the action of hydrogen fluoride on urano-uranic oxide or on uranous oxide or by reduction of a solution of uranyl fluoride with stannous chloride. It is also formed with uranium hexafluoride when the pentachloride is acted upon by fluorine at —40° C. thus ... 

Cascade theory has been applied to the separation of uranium 235 by gaseous diifusion of uranium hexafluoride the ratio of the diffusion rates for uranium 233 and uranium 238 is 1.0043. With about 3900 equilibration stages a product containing 90 mole % uranium 235 can be obtained from natural uranium (0.71 mole %), giving a residue with 0.22 mole % uranium 235. The feed in this case is injected at the 550th stage. 

Two processes are employed for the production of uranium(VI) fluoride, namely the wet and dry processes. In both processes uranium(IV) oxide and uranium(lV) fluoride are formed as intermediates. In the wet process the uranium(IV) oxide is produced from the uranium concentrate by way of uranyl nitrate, whereas in the dry process the uranium concentrate is directly reduced to uranium(IV) oxide. The methods of purification used are also different in the wet process the purification proceeds at the uranyl nitrate stage, by solvent extraction, whereas in the dry process the end product uranium hexafluoride is itself distillatively purified. 

Fluorine is combined either directly or indirectly with other elements to form compounds such as hydrofluoric acid, fluoropolymers and is used in the synthesis of organic fluorine compounds such as fluorides as in the manufacture of Freon (i.e., dichlo-rodifluoromethane, CCI2F2), which is used as a refrigerant. Fluorine is used in the manufacture of uranium hexafluoride that is necessary for the separation of the isotopes of uranium in centrifuges in the production of nuclear weapons. Fluorine and its compounds are used in producing more than 100... 

Now, let s return to our discussion of attractions between molecules (intermolecular attractions). Fiydrogen fluoride, FiF, is used to make uranium hexafluoride, UF6, a chemical that plays an important role in the production of nuclear reactor fuel. Chemists have learned that gaseous hydrogen fluoride condenses to a liquid at... 

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