Uranium oxide tetrafluoride

The chemistry of uranium oxide tetrafluoride (UOF4) in superacids has been thoroughly studied by Holloway and eo-workers (Bougon et al. 1978,1979, Holloway et al. 1983). Due to the limited solubility of UOF4 in HF or HF-based superacids, and also because such UOF4 solutions are unstable, undergoing redistribution reactions with time to form and UFg, these compounds are best prepared by direct... 

Mixtures of uranium oxides ( yellow cake ) are produced in the processing of uranium ores and can result in occupational exposures in uranium mill workers. Exposure to uranium tetrafluoride and hexafluoride is a potential for workers in the uranium enrichment industry. 

Preparation of uranium metal. As discussed previously, some nuclear power plant reactors such as the UNGG type have required in the past a nonenriched uranium metal as nuclear fuel. Hence, such reactors were the major consumer of pure uranium metal. Uranium metal can be prepared using several reduction processes. First, it can be obtained by direct reduction of uranium halides (e.g., uranium tetrafluoride) by molten alkali metals (e.g., Na, K) or alkali-earth metals (e.g.. Mg, Ca). For instance, in the Ames process, uranium tetrafluoride, UF, is directly reduced by molten calcium or magnesium at yoO C in a steel bomb. Another process consists in reducing uranium oxides with calcium, aluminum (i.e., thermite or aluminothermic process), or carbon. Third, the pure metal can also be recovered by molten-salt electrolysis of a fused bath made of a molten mixture of CaCl and NaCl, with a solute of KUFj or UF. However, like hafnium or zirconium, high-purity uranium can be prepared according to the Van Arkel-deBoer process, i.e., by the hot-wire process, which consists of thermal decomposition of uranium halides on a hot tungsten filament (similar in that way to chemical vapor deposition, CVD). 

The mined uranium ore is crushed and ground into a fine powder. After ore dressing, the concentrate is leached with sulfuric acid. The solution is treated in a Hq-uid-Hquid extraction, in which uranium is transferred to an organic phase. It is extracted from that with ammonia, and ammonium uranate is precipitated. At 1000°C it is decomposed to yellow uranium oxide UOj. Uranium hexafluoride is prepared by treating the oxide with hydrogen fluoride to make uranium tetrafluoride. This in turn is treated with elemental fluorine to prepare the gaseous hexafluoride UF (sub-Hmation point 56°C). 

One of the most important examples of the fluorination of oxides is the fluorination of uranium dioxide. Uranium tetrafluoride (UF4) is the intermediate compound which is reduced to uranium metal. The gaseous higher fluoride, uranium hexafluoride (UF6) is used for the separation of uranium isotopes to obtain enriched uranium (i.e., uranium containing a higher proportion of the isotope, U235, than natural uranium). 

The double fluoride, ammonium hexafluorovanadate ((NH4)3VF6), forms from the oxide at 210 to 250 °C, but decomposes at 600 to 700 °C to yield pure vanadium fluoride. Examples of metal fluorides obtainable through the double fluoride route include uranium tetrafluoride, beryllium difluoride and the rare earth fluorides ... 

Tetrafluoroammonium hexafluoromanganate, 4384 Tetrafluoroammonium hexafluoronickelate, 4385 Tetrafluoroammonium hexafluoroxenate Tetranitromethane, 0546 Titanium tetraperchlorate, 4170 1,1,1 -Triacetoxy-1,2-benziodoxol-3-one, 3610 Trifluoromethyl hypofluorite, 0353 Trimethylsilyl chlorochromate, 1301 Trioxygen difluoride , 4323 Uranium hexafluoride, 4375 Vanadium(V) oxide, 4866 Vanadium trinitrate oxide, 4763 Vanadyl perchlorate, 4152 Xenon hexafluoride, 4377 Xenon(II) pentafluoroorthoselenate, 4382 Xenon(II) pentafluoroorthotellurate, 4383 Xenon tetrafluoride, 4353 Xenon tetrafluoride oxide, 4346 Xenon tetraoxide, 4863 Xenon trioxide, 4857 Zinc permanganate, 4710... 

Uses. Conversion of uranium tetrafluoride to uranium hexafluoride oxidizer in rocket fuel systems manufacture of various fluorides and fluorocarbons... 

Metallic uranium can be prepared from its oxides or hahdes by reduction at high temperature. Uranium dioxide, UO2, or other oxides such as UO3 or UsOs may be reduced to uranium metal by heating with carbon, calcium or aluminum at high temperatures. Similarly, uranium tetrafluoride or other halides can be reduced to metal by heating with sodium, potassium, calcium, or magnesium at high temperatures. Alternatively, uranium tetrafluoride mixed with fused alkali chlorides is electrolyzed to generate uranium metal. 

Tetrafluoroammonium hexafluoromanganate, 4378 Tetrafluoroammonium hexafluoronickelate, 4379 Tetrafluoroammonium hexafluoroxenate, 4380 Tetranitromethane, 0543 Titanium tetraperchlorate, 4164 1,1,1 -Triacetoxy-1,2-benziodoxol-3-one, 3604 Trifluoromethyl hypofluorite, 0352 Trimethylsilyl chlorochromate, 1297 Trioxygen difluoride , 4317 Uranium hexafluoride, 4369 Vanadium trinitrate oxide, 4758 Vanadium(V) oxide, 4860 Vanadyl perchlorate, 4146 Xenon hexafluoride, 4371 Xenon tetrafluoride, 4347 Xenon tetrafluoride oxide, 4340 Xenon tetraoxide, 4857 Xenon trioxide, 4851 Xenon(II) pentafluoroorthoselenate, 4376 Xenon(II) pentafluoroorthotellurate, 4377 Zinc permanganate, 4705 ACETYLENIC PEROXIDES ACYL HYPOHALITES ALKYL HYDROPEROXIDES ALKYL TRIALKYLLEAD PEROXIDES AMINIUM IODATES AND PERIODATES AMMINECHROMIUM PEROXOCOMPLEXES BIS (FLUOROOXY)PERHALOALKANES BLEACHING POWDER CHLORITE SALTS... 

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 ... 

Tn reviewing the chemistry of the actinides as a group, the simplest approach is to consider each valence state separately. In the tervalent state, and such examples of the divalent state as are known, the actinides show similar chemical behavior to the lanthanides. Experimental diflB-culties with the terpositive actinides up to plutonium are considerable because of the ready oxidation of this state. Some correlation exists with the actinides in studies of the lanthanide tetrafluorides and fluoro complexes. For other compounds of the 4-valent actinides, protactinium shows almost as many similarities as dijSerences between thorium and the uranium-americium set thus investigating the complex forming properties of their halides has attracted attention. In the 5- and 6-valent states, the elements from uranium to americium show a considerable degree of chemical similarity. Protactinium (V) behaves in much the same way as these elements in the 5-valent state except for water, where its hydrolytic behavior is more reminiscent of niobium and tantalum. 

Attempts to confirm the existence of platinum difluoride have been unsuccessful. Platinum tetrafluoride has been shown to be diamagnetic when pure. Although it is not isomorphous with any known tetrafluoride it is apparently related structurally to uranium tetrachloride. The quinque-positive oxidation state of platinum has been established in the simple fluoride, the salts potassium hexafluoroplatinate(v) and dioxygenyl hexa-fluoroplatinate(v), and in the adducts ClFj.PtFj and IFj.PtFj. Platinum hexafluoride has been briefly investigated. 

Uranium hexafluoride is the key compound in the separation of the uranium isotopes and In its manufacture uranium(lV) oxide is first reacted with hydrogen fluoride to uranium tetrafluoride, which is then reacted with elemental fluorine to uranium hexalluoride ... 

Derivation Finely ground ore is leached under oxidizing conditions to give uranyl nitrate solution. The uranyl nitrate, purified by solvent extraction (ether, alkyl phosphate esters), is then reduced with hydrogen to uranium dioxide. This is treated with hydrogen fluoride to obtain uranium tetrafluoride, followed by either electrolysis in fused salts or by reduction with calcium or magnesium. Uranium can also be recovered from phosphate sand. 

ABSOLUTE ALCOHOL or ABSOLUTE ETHANOL (64-17-5) Forms explosive mixture with air (flash point 55°F/13°C). Reacts, possibly violently, with strong oxidizers, bases, acetic anhydride, acetyl bromide, acetyl chloride, aliphatic amines, bromine pentafluoride, calcium oxide, cesium oxide, chloryl perchlorate, disulfuryl difluoride, ethylene glycol methyl ether. Iodine heptafluoride, isocyanates, nitrosyl perchlorate, perchlorates, platinum, potassium- er -butoxide, potassium, potassium oxide, potassium peroxide, phosphonis(III) oxide, silver nitrate, silver oxide, sulfuric acid, oleum, sodium, sodium hydrazide, sodium peroxide, sulfmyl cyanamide, tetrachlorosilane, i-triazine-2,4,6-triol, triethoxydialuminum tribromide, triethylaluminum, uranium fluoride, xenon tetrafluoride. Mixture with mercury nitrate(II) forms explosive mercury fulminate. Forms explosive complexes with perchlorates, magnesium perchlorate (forms ethyl perchlorate), silver perchlorate. Flow or agitation of substance may generate electrostatic charges due to low conductivity. 

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