Powdered yellowcake in a drum

Yellowcakes (also known as urania) are uranium concentrates obtained from leach solutions. They represent an intermediate step in the processing of uranium ores. 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 which is insoluble in water and contains about 80% uranium oxide, and which melts at approximately 2878°C. Yellowcake (refined uranium oxide). ... Yellowcake (refined uranium oxide). ... General Name, Symbol, Number uranium, U, 92 Chemical series actinides Group, Period, Block n/a, 7, f Appearance silvery gray metallic; corrodes to a spalling black oxide coat in air Atomic mass 238. ... Leaching is the process of extracting a substance from a solid by dissolving it in a liquid. ... Iron ore (Banded iron formation) Manganese ore Lead ore Gold ore An ore is a volume of rock containing components or minerals in a mode of occurrence which renders it valuable for mining. ...

The ore is first crushed to a fine powder by passing raw uranium ore through crushers and grinders to produce "pulped" ore. This is further processed with concentrated acid, alkaline, or peroxide solutions to leach out the uranium. Yellowcake is what remains after drying and filtering. The yellowcake produced by most modern mills is actually brown or black, not yellow; the name comes from the colour and texture of the concentrates produced by early mining operations. For other senses of this word, see acid (disambiguation). ... The common (Arrhenius) definition of a base is a chemical compound that either donates hydroxide ions or absorbs hydrogen ions when dissolved in water. ... Peroxide has three distinct meanings: // Main article: hydrogen peroxide In common usage, peroxide is an aqueous solution of hydrogen peroxide (HOOH or H2O2) sold for use as a disinfectant or mild bleach. ...

Initially, the compounds formed in yellowcakes were not identified; in 1970, the U.S. Bureau of Mines still referred to yellowcakes as the final precipitate formed in the milling process and considered it to be ammonium diuranate or sodium diuranate. The compositions were variable and depended upon the leachant and subsequent precipitating conditions. Among the compounds identified in yellowcakes include: uranyl hydroxide, uranyl sulfate, sodium para-uranate, and uranyl peroxide, along with various uranium oxides. Modern yellowcake typically contains 70 to 90 percent triuranium octaoxide (U₃O₈) by weight. (Other uranium oxides, such as uranium dioxide (UO₂) and uranium trioxide (UO₃), exist) For most of the 20th century, the U.S. Bureau of Mines (USBM) was the primary United States Government agency conducting scientific research and disseminating information on the extraction, processing, use, and conservation of mineral resources. ... Ammonium diuranate or (ADU) (NH4U2O7), is one of the intermediate chemical forms of uranium produced during yellowcake production. ... Sodium diuranate, Na2U2O7·6H2O, is a uranium salt also known as the yellow oxide of uranium. ... Uranyl hydroxide is a hydroxide of uranium with the chemical formula UO2(OH)2 in the monomeric form and (UO2)2(OH)2 in the dimeric; both isomers may exist in normal aqueous media. ... Uranyl sulfate (U02S04) a sulfate of uranium presents as an odorless lemon-yellow sand-like solid in its pure crystaline form. ... Sodium uranate or Yellow uranium oxide, a uranium compound with the chemical fomula Na2O (UO3)2. ... Uranyl peroxide or Uranium peroxide hydrate (UO4·nH2O) is a pale-yellow, soluble peroxide of uranium. ... Uranium oxide is an oxide of the element uranium. ... Triuranium octaoxide (U3O8) is a compound of uranium. ... UO2 A black, radioactive, crystalline powder, once used in the late 1800s to mid-1900s in ceramic glazes. ... Uranium trioxide (UO3), also called uranyl oxide, uranium(VI) oxide, and uranic oxide, is the hexavalent oxide of uranium. ...

Yellowcake is used in the preparation of fuel for nuclear reactors, where it is processed into purified UO₂ for use in fuel rods for PHWR and other systems using unenriched uranium. It may also be enriched, by being converted to uranium hexafluoride gas (UF₆), by isotope separation though gaseous diffusion or in a gas centrifuge to produce enriched uranium suitable for use in weapons and reactors. Core of a small nuclear reactor used for research. ... A pressurised heavy water reactor is a nuclear power reactor that uses unenriched natural uranium as its fuel and heavy water as a moderator (deuterium oxide D2O). ... Natural uranium (NU) refers to refined uranium with the same isotopic ratios as found in nature. ... Enriched uranium is uranium whose uranium-235 content has been increased through the process of isotope separation. ... Uranium hexafluoride, or UF6, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons. ... Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes, for example separating natural uranium into enriched uranium and depleted uranium. ... -1... The gas centrifuge is a hyper-centrifuge used to produce enriched uranium. ...

Yellowcake is produced by all countries in which uranium is mined.

References

Characterizing and Classifying Uranium Yellow Cakes: A Background by Donald M. Hausen JOM-9812-45F

See also

• Uraninite
• Yellowcake forgery

For the band, see Pitchblende (band). ... The term Yellowcake Forgery refers to falsified classified documents initially uncovered by Italian intelligence which possibly depicted an attempt by Iraqs Saddam Hussein regime to purchase yellowcake uranium from the country of Niger, in defiance of United Nations sanctions. ...

External links

• Links to external chemical sources.