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Uranium Trioxide
Uranium trioxide (UO3), also called uranyl oxide, uranium(VI) oxide, and uranic oxide, is the hexavalent oxide of uranium. The solid may be obtained by heating uranyl nitrate to 400 °C. Its most commonly encountered polymorph, γ-UO3, is a yellow-orange powder. Production and use There are three methods to generate uranium trioxide. As noted below, two are used industrially in the reprocessing of nuclear fuel and uranium enrichment. # U3O8 can be oxidized at 500 °C with oxygen. Note that above 750 °C even in 5 atm O2 UO3 decomposes into U3O8. # Uranyl nitrate, UO2(NO3)2·6H2O can be heated to yield UO3. This occurs during the reprocessing of nuclear fuel. Fuel rods are dissolved in HNO3 to separate uranyl nitrate from plutonium and the fission products (the PUREX method). The pure uranyl nitrate is converted to solid UO3 by heating at 400 °C. After reduction with hydrogen (with other inert gas present) to uranium dioxide, the uranium can be used in n ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Uranium Dioxide
Uranium dioxide or uranium(IV) oxide (), also known as urania or uranous oxide, is an oxide of uranium, and is a black, radioactive, crystalline powder that naturally occurs in the mineral uraninite. It is used in nuclear fuel rods in nuclear reactors. A mixture of uranium and plutonium dioxides is used as MOX fuel. Prior to 1960, it was used as yellow and black color in ceramic glazes and glass. Production Uranium dioxide is produced by reducing uranium trioxide with hydrogen. :UO3 + H2 → UO2 + H2O at 700 °C (973 K) This reaction plays an important part in the creation of nuclear fuel through nuclear reprocessing and uranium enrichment. Chemistry Structure The solid is isostructural with (has the same structure as) fluorite (calcium fluoride), where each U is surrounded by eight O nearest neighbors in a cubic arrangement. In addition, the dioxides of cerium, thorium, and the transuranic elements from neptunium through californium have the same structures. No ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Sodium Diuranate
Sodium diuranate, Na2U2O7·6H2O, is a uranium salt also known as the yellow oxide of uranium. Sodium diuranate is commonly referred to by the initials SDU. Along with ammonium diuranate it was a component in early yellowcakes. The ratio of the two compounds is determined by process conditions; however, yellowcake is now largely a mix of uranium oxides. Preparation In the classical procedure for extracting uranium, pitchblende is broken up and mixed with sulfuric and nitric acids. The uranium dissolves to form uranyl sulfate and sodium carbonate is added to precipitate impurities. If the uranium in the ore is in the tetravalent oxidation state, an oxidiser is added to oxidise it to the hexavalent oxidation state, and sodium hydroxide is then added to make the uranium precipitate as sodium diuranate. The alkaline process of milling uranium ores involves precipitating sodium uranate from the pregnant leaching solution to produce the semi-refined product referred to as yellowcake ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Royal Society
The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, recognising excellence in science, supporting outstanding science, providing scientific advice for policy, education and public engagement and fostering international and global co-operation. Founded on 28 November 1660, it was granted a royal charter by King Charles II as The Royal Society and is the oldest continuously existing scientific academy in the world. The society is governed by its Council, which is chaired by the Society's President, according to a set of statutes and standing orders. The members of Council and the President are elected from and by its Fellows, the basic members of the society, who are themselves elected by existing Fellows. , there are about 1,700 fellows, allowed to use the postnominal title FRS (Fellow of the ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Metastudtite
Studtite, chemical formula UO2)O2(H2O)2·2(H2O) or UO4·4(H2O), is a secondary uranium mineral containing peroxide formed by the alpha- radiolysis of water during formation. It occurs as pale yellow to white needle-like crystals often in acicular, white sprays. Studtite was originally described by Vaes in 1947Annales de la Société Géologique de Belgique - 1947 - pp B212 to B226- J.F. Vaes - Six nouveaux minéraux d'urane provenant de Shinkolobwe (Katanga) - from specimens from Shinkolobwe, Katanga Copper Crescent, Katanga (Shaba), Democratic Republic of Congo, and has since been reported from several other localities. The mineral was named for Franz Edward Studt, an English prospector and geologist who was working for the Belgians. When exposed to air studtite converts over a short time to the metastudtite UO4·2(H2O) form. Despite their apparent chemical simplicity, these two uranyl species are the only reported peroxide minerals. They may also be readily formed on the su ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Studtite
Studtite, chemical formula UO2)O2(H2O)2·2(H2O) or UO4·4(H2O), is a secondary uranium mineral containing peroxide formed by the alpha-radiolysis of water during formation. It occurs as pale yellow to white needle-like crystals often in acicular, white sprays. Studtite was originally described by Vaes in 1947Annales de la Société Géologique de Belgique - 1947 - pp B212 to B226- J.F. Vaes - Six nouveaux minéraux d'urane provenant de Shinkolobwe (Katanga) - from specimens from Shinkolobwe, Katanga Copper Crescent, Katanga (Shaba), Democratic Republic of Congo, and has since been reported from several other localities. The mineral was named for Franz Edward Studt, an English prospector and geologist who was working for the Belgians. When exposed to air studtite converts over a short time to the metastudtite UO4·2(H2O) form. Despite their apparent chemical simplicity, these two uranyl species are the only reported peroxide minerals. They may also be readily formed on the surfa ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Schoepite
Schoepite, empirical formula (UO2)8O2(OH)12•12(H2O) is a rare alteration product of uraninite in hydrothermal uranium deposits. It may also form directly from ianthinite. The mineral presents as a transparent to translucent yellow, lemon yellow, brownish yellow, or amber orthorhombic tabular crystals. Although over 20 other crystal forms have been noted; rarely in microcrystalline aggregates. When exposed to air schoepite converts over a short time to the metaschoepite form (UO3 • H2O, ) within a few months of being exposed to ambient air. The hardness is 2.5, density is 4.8 g/cm3, and it streaks yellow. It was first described from specimens from Shinkolobwe mine in Belgian Congo in 1923, several additional localities are known. Schoepite was named to honor Alfred Schoep (1881–1966), Professor of Mineralogy at the University of Ghent, Belgium Belgium, ; french: Belgique ; german: Belgien officially the Kingdom of Belgium, is a country in Northwestern Europe. ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Coffinite
Coffinite is a uranium-bearing silicate mineral with formula: U(SiO4)1−x(OH)4x. It occurs as black incrustations, dark to pale-brown in thin section. It has a grayish-black streak. It has a brittle to conchoidal fracture. The hardness of coffinite is between 5 and 6. It was first described in 1954 for an occurrence at the La Sal No. 2 Mine, Beaver Mesa, Mesa County, Colorado, US, and named for American geologist Reuben Clare Coffin (1886–1972). It has widespread global occurrence in Colorado Plateau-type uranium ore deposits of uranium and vanadium. It replaces organic matter in sandstone and in hydrothermal vein type deposits. It occurs in association with uraninite, thorite, pyrite, marcasite, roscoelite, clay minerals and amorphous organic matter. Composition Coffinite's chemical formula is U(SiO4)1−x(OH)4x. X-ray powder patterns from samples of coffinite allowed geologists to classify it as a new mineral in 1955. A comparison to the x-ray powder pattern of zircon (ZrS ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Blind River, Ontario
Blind River is a town situated on the North Channel of Lake Huron in the Algoma District, Ontario, Canada. The town, named after the nearby Blind River, celebrated its centennial in 2006. History French explorers discovered the North Channel and made it a renowned voyageur route. Fur traders, loggers and miners followed to seek natural resources. A fur trading post was established by the North West Company in 1789 at the mouth of the Mississagi River. When the fur trade slowed about 1820, the Hudson's Bay Company purchased the North West Company. A number of trappers settled along the rivers flowing into Lake Huron. One of the rivers, just three miles (5 km) east of the Mississagi mouth, was called Penewobecong, which translates to "smooth rock or sloping". The voyageurs named the river the Blind River because the mouth was not easily visible along the canoe route. The name Blind River was adopted by the settlement that grew at the mouth of the river. Blind River's post o ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Cameco Corporation
Cameco Corporation (formerly Canadian Mining and Energy Corporation) is the world's largest publicly traded uranium company, based in Saskatoon, Saskatchewan, Canada. In 2015, it was the world's second largest uranium producer, accounting for 18% of world production. History The Canadian Mining and Energy Corporation was formed in 1988 by the merger and privatization of two Crown corporations: the federally owned Eldorado Nuclear Limited (known previously as Eldorado Mining and Refining Limited) and Saskatchewan-based Saskatchewan Mining Development Corporation (SMDC). The name was later shortened to "Cameco Corporation". The new company was initially owned 62% by the provincial government and 38% by the federal government. The initial public offering (IPO) for 20% of the company was conducted in July, 1991. Government ownership of the company decreased over the next eleven years, with full privatization occurring in February, 2002. In 1996, Cameco acquired Power Resources ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Reprocessed Uranium
Reprocessed uranium (RepU) is the uranium recovered from nuclear reprocessing, as done commercially in France, the UK and Japan and by nuclear weapons states' military plutonium production programs. This uranium makes up the bulk of the material separated during reprocessing. Commercial LWR spent nuclear fuel contains on average (excluding cladding) only four percent plutonium, minor actinides and fission products by weight. Despite it often containing more fissile material than natural uranium, reuse of reprocessed uranium has not been common because of low prices in the uranium market of recent decades, and because it contains undesirable isotopes of uranium. Given sufficiently high uranium prices, it is feasible for reprocessed uranium to be re- enriched and reused. A higher enrichment level is required to compensate for the 236U which is lighter than 238U and therefore concentrates in the enriched product. As enrichment concentrates lighter isotopes on the "enriched" side an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
Mining
Mining is the extraction of valuable minerals or other geological materials from the Earth, usually from an ore body, lode, vein, seam, reef, or placer deposit. The exploitation of these deposits for raw material is based on the economic viability of investing in the equipment, labor, and energy required to extract, refine and transport the materials found at the mine to manufacturers who can use the material. Ores recovered by mining include metals, coal, oil shale, gemstones, limestone, chalk, dimension stone, rock salt, potash, gravel, and clay. Mining is required to obtain most materials that cannot be grown through agricultural processes, or feasibly created artificially in a laboratory or factory. Mining in a wider sense includes extraction of any non-renewable resource such as petroleum, natural gas, or even water. Modern mining processes involve prospecting for ore bodies, analysis of the profit potential of a proposed mine, extraction of the desired materials, an ... [...More Info...] [...Related Items...] OR: [Wikipedia] [Google] [Baidu] |
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] |
