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Uranium Hexafluoride
Uranium hexafluoride (), (sometimes called "hex") is an inorganic compound with the formula UF6. Uranium hexafluoride is a volatile white solid that reacts with water, releasing corrosive hydrofluoric acid. The compound reacts mildly with aluminium, forming a thin surface layer of AlF3 that resists any further reaction from the compound. UF6 is used in the process of enriching uranium, which produces fuel for nuclear reactors and nuclear weapons. Preparation Milled uranium ore—U3O8 or "yellowcake"—is dissolved in nitric acid, yielding a solution of uranyl nitrate UO2(NO3)2. Pure uranyl nitrate is obtained by solvent extraction, then treated with ammonia to produce ammonium diuranate ("ADU", (NH4)2U2O7). Reduction with hydrogen gives UO2, which is converted with hydrofluoric acid (HF) to uranium tetrafluoride, UF4. Oxidation with fluorine yields UF6. During nuclear reprocessing, uranium is reacted with chlorine trifluoride to give UF6: :U + 2 ClF3 → UF6 + Cl2 Prope ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Chloroform
Chloroform, or trichloromethane, is an organic compound with chemical formula, formula Carbon, CHydrogen, HChlorine, Cl3 and a common organic solvent. It is a colorless, strong-smelling, dense liquid produced on a large scale as a precursor to PTFE. It is also a precursor to various refrigerants. It is trihalomethane. It is a powerful anesthetic, euphoriant, anxiolytic, and sedative when inhaled or ingested. Structure The molecule adopts a tetrahedral molecular geometry with C3v symmetry group, symmetry. Natural occurrence The total global flux of chloroform through the environment is approximately tonnes per year, and about 90% of emissions are natural in origin. Many kinds of seaweed produce chloroform, and fungi are believed to produce chloroform in soil. Abiotic processes are also believed to contribute to natural chloroform productions in soils although the mechanism is still unclear. Chloroform volatilizes readily from soil and surface water and undergoes degradation in ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Inorganic Compound
In chemistry, an inorganic compound is typically a chemical compound that lacks carbon–hydrogen bonds, that is, a compound that is not an organic compound. The study of inorganic compounds is a subfield of chemistry known as '' inorganic chemistry''. Inorganic compounds comprise most of the Earth's crust, although the compositions of the deep mantle remain active areas of investigation. Some simple carbon compounds are often considered inorganic. Examples include the allotropes of carbon (graphite, diamond, buckminsterfullerene, etc.), carbon monoxide, carbon dioxide, carbides, and the following salts of inorganic anions: carbonates, cyanides, cyanates, and thiocyanates. Many of these are normal parts of mostly organic systems, including organisms; describing a chemical as inorganic does not necessarily mean that it does not occur within living things. History Friedrich Wöhler's conversion of ammonium cyanate into urea in 1828 is often cited as the starting point of modern ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonium Diuranate
Ammonium diuranate or (ADU) ((NH4)2U2O7), is one of the intermediate chemical forms of uranium produced during yellowcake production. The name "yellowcake" originally given to this bright yellow salt, now applies to mixtures of uranium oxides which are actually hardly ever yellow. It also is an intermediate in mixed-oxide (MOX) fuel fabrication. Although it is usually called "ammonium diuranate" as though it has a "diuranate" ion , this is not necessarily the case. It can also be called diammonium diuranium heptaoxide. The structure is said to be similar to that of uranium dioxide dihydrate. It is precipitated by adding aqueous ammonium hydroxide after uranium extraction by tertiary amines in kerosene. This precipitate is then thickened and centrifuged before being calcined to uranium oxide. Canadian practice favours the production of uranium oxide from ammonium diuranate, rather than from uranyl nitrate Uranyl nitrate is a water-soluble yellow uranium salt with the formula . The ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Ammonia
Ammonia is an inorganic compound of nitrogen and hydrogen with the formula . A stable binary hydride, and the simplest pnictogen hydride, ammonia is a colourless gas with a distinct pungent smell. Biologically, it is a common nitrogenous waste, particularly among aquatic organisms, and it contributes significantly to the nutritional needs of terrestrial organisms by serving as a precursor to 45% of the world's food and fertilizers. Around 70% of ammonia is used to make fertilisers in various forms and composition, such as urea and Diammonium phosphate. Ammonia in pure form is also applied directly into the soil. Ammonia, either directly or indirectly, is also a building block for the synthesis of many pharmaceutical products and is used in many commercial cleaning products. It is mainly collected by downward displacement of both air and water. Although common in nature—both terrestrially and in the outer planets of the Solar System—and in wide use, ammonia is both caust ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Solvent Extraction
A solvent (s) (from the Latin '' solvō'', "loosen, untie, solve") is a substance that dissolves a solute, resulting in a solution. A solvent is usually a liquid but can also be a solid, a gas, or a supercritical fluid. Water is a solvent for polar molecules and the most common solvent used by living things; all the ions and proteins in a cell are dissolved in water within the cell. The quantity of solute that can dissolve in a specific volume of solvent varies with temperature. Major uses of solvents are in paints, paint removers, inks, and dry cleaning. Specific uses for organic solvents are in dry cleaning (e.g. tetrachloroethylene); as paint thinners (toluene, turpentine); as nail polish removers and solvents of glue (acetone, methyl acetate, ethyl acetate); in spot removers (hexane, petrol ether); in detergents ( citrus terpenes); and in perfumes (ethanol). Solvents find various applications in chemical, pharmaceutical, oil, and gas industries, including in chemical syn ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranyl Nitrate
Uranyl nitrate is a water-soluble yellow uranium salt with the formula . The hexa-, tri-, and dihydrates are known. The compound is mainly of interest because it is an intermediate in the preparation of nuclear fuels. Uranyl nitrate can be prepared by reaction of uranium salts with nitric acid. It is soluble in water, ethanol, and acetone. As determined by neutron diffraction, the uranyl center is characteristically linear with short U=O distances. In the equatorial plane of the complex are six U-O bonds to bidentate nitrate and two water ligands. At 245 pm, these U-O bonds are much longer than the U=O bonds of the uranyl center. Uses Processing of nuclear fuels Uranyl nitrate is important for nuclear reprocessing. It is the compound of uranium that results from dissolving the decladded spent nuclear fuel rods or yellowcake in nitric acid, for further separation and preparation of uranium hexafluoride for isotope separation for preparing of enriched uranium. A special feature ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nitric Acid
Nitric acid is the inorganic compound with the formula . It is a highly corrosive mineral acid. The compound is colorless, but older samples tend to be yellow cast due to decomposition into oxides of nitrogen. Most commercially available nitric acid has a concentration of 68% in water. When the solution contains more than 86% , it is referred to as ''fuming nitric acid''. Depending on the amount of nitrogen dioxide present, fuming nitric acid is further characterized as red fuming nitric acid at concentrations above 86%, or white fuming nitric acid at concentrations above 95%. Nitric acid is the primary reagent used for nitration – the addition of a nitro group, typically to an organic molecule. While some resulting nitro compounds are shock- and thermally-sensitive explosives, a few are stable enough to be used in munitions and demolition, while others are still more stable and used as pigments in inks and dyes. Nitric acid is also commonly used as a strong oxidizing agen ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Yellowcake
Yellowcake (also called urania) is a type of uranium concentrate powder obtained from leach solutions, in an intermediate step in the processing of uranium ores. It is a step in the processing of uranium after it has been mined but before fuel fabrication or uranium enrichment. Yellowcake concentrates are prepared by various extraction and refining methods, depending on the types of ores. Typically, yellowcakes are obtained through the milling and chemical processing of uranium ore, forming a coarse powder that has a pungent odor, is insoluble in water, and contains about 80% uranium oxide, which melts at approximately 2880 °C. Overview Originally raw uranium ore was extracted by traditional mining and this is still the case in many mines. It is first crushed to a fine powder by passing it through crushers and grinders to produce "pulped" ore. This is further processed with concentrated acid, alkaline, or peroxide solutions to leach out the uranium. However, nearly ha ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb types release large quantities of energy from relatively small amounts of matter. The first test of a fission ("atomic") bomb released an amount of energy approximately equal to . The first thermonuclear ("hydrogen") bomb test released energy approximately equal to . Nuclear bombs have had yields between 10 tons TNT (the W54) and 50 megatons for the Tsar Bomba (see TNT equivalent). A thermonuclear weapon weighing as little as can release energy equal to more than . A nuclear device no larger than a conventional bomb can devastate an entire city by blast, fire, and radiation. Since they are weapons of mass destruction, the proliferation of nuclear weapons is a focus of international relations policy. Nuclear weapons have been d ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Nuclear Reactor
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nuclear fission is passed to a working fluid (water or gas), which in turn runs through steam turbines. These either drive a ship's propellers or turn electrical generators' shafts. Nuclear generated steam in principle can be used for industrial process heat or for district heating. Some reactors are used to produce isotopes for medical and industrial use, or for production of weapons-grade plutonium. , the International Atomic Energy Agency reports there are 422 nuclear power reactors and 223 nuclear research reactors in operation around the world. In the early era of nuclear reactors (1940s), a reactor was known as a nuclear pile or atomic pile (so-called because the graphite moderator blocks of the first reactor were placed into a tall pi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Enriched Uranium
Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U with 99.2739–99.2752% natural abundance), uranium-235 (235U, 0.7198–0.7202%), and uranium-234 (234U, 0.0050–0.0059%). 235U is the only nuclide existing in nature (in any appreciable amount) that is fissile with thermal neutrons. Enriched uranium is a critical component for both civil nuclear power generation and military nuclear weapons. The International Atomic Energy Agency attempts to monitor and control enriched uranium supplies and processes in its efforts to ensure nuclear power generation safety and curb nuclear weapons proliferation. There are about 2,000 tonnes of highly enriched uranium in the world, produced mostly for nuclear power, nuclear weapons, naval propulsion, and smaller quantities for research reactors ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Aluminium Fluoride
Aluminium fluoride refers to inorganic compounds with the formula AlF3·''x''H2O. They are all colorless solids. Anhydrous AlF3 is used in the production of aluminium metal. Several occur as minerals. Occurrence and production Aside from anhydrous AlF3, several hydrates are known. With the formula AlF3·''x''H2O, these compounds include monohydrate (''x'' = 1), two polymorphs of the trihydrate (''x'' = 3), a hexahydrate (''x'' = 6), and a nonahydrate (''x'' = 9). The majority of aluminium fluoride is produced by treating alumina with hydrogen fluoride at 700 °C: Hexafluorosilicic acid may also be used make aluminum fluoride. :H2SiF6 + Al2O3 + 3 H2O → 2 AlF3 + SiO2 + 4 H2O Alternatively, it is manufactured by thermal decomposition of ammonium hexafluoroaluminate. For small scale laboratory preparations, AlF3 can also be prepared by treating aluminium hydroxide or aluminium metal with hydrogen fluoride. Aluminium fluoride trihydrate is found in nature as the rare mi ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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