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The metal uranium forms several oxides: Uranium dioxide or uranium(IV) oxide (UO 2, the mineral uraninite or pitchblende) Diuranium pentoxide or uranium(V) oxide (U 2 O 5) Uranium trioxide or uranium(VI) oxide (UO 3) Triuranium octoxide (U 3 O 8), the most stable uranium oxide; yellowcake typically contains 70 to 90 percent triuranium octoxide)
Uranium dioxide or uranium(IV) oxide (UO 2), 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.
The most common forms of uranium oxide are triuranium octoxide (U 3 O 8) and UO 2. [3] Both oxide forms are solids that have low solubility in water and are relatively stable over a wide range of environmental conditions. Triuranium octoxide is (depending on conditions) the most stable compound of uranium and is the form most commonly found in ...
The use of pitchblende, uranium in its natural oxide form, dates back to at least the year 79 AD, when it was used in the Roman Empire to add a yellow color to ceramic glazes. [12] Yellow glass with 1% uranium oxide was found in a Roman villa on Cape Posillipo in the Gulf of Naples, Italy, by R. T. Gunther of the University of Oxford in 1912. [29]
Uraninite, also known as pitchblende, is a radioactive, uranium-rich mineral and ore with a chemical composition that is largely UO 2 but because of oxidation typically contains variable proportions of U 3 O 8. Radioactive decay of the uranium causes the mineral to contain oxides of lead and trace amounts of helium.
Natural uranium (99.3% U-238, 0.7% U-235) in fast breeder reactor: 86,000,000: Reactor-grade uranium (3.5% U-235) in light-water reactor: ... Silver-oxide [19] 0.47: 1.8:
Yellowcake (also called urania) is a type of powdered uranium concentrate 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 ...
In the presence of oxygen (O 2), uranium dioxide (UO 2) is oxidized to U 3 O 8, whereas uranium trioxide (UO 3) loses oxygen at temperatures above 500 °C and is reduced to U 3 O 8. The compound can be produced by any one of three primary chemical conversion processes, involving either uranium tetrafluoride (UF 4) or uranyl fluoride (UO 2 F 2) as