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Information about Yellowcake

For the falsified documents, see Yellowcake forgery.


Yellowcake
Other namesurania
Properties
Molecular formulaU3O8
Density2.055 g/cm3, solid
Melting point 2878°C
Except where noted otherwise, data are given for
materials in their standard state
(at 25 C, 100 kPa)


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.

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.

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 octoxide (U3O8) by weight. (Other uranium oxides, such as uranium dioxide (UO2) and uranium trioxide (UO3), exist)

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 through gaseous diffusion or in a gas centrifuge to produce enriched uranium suitable for use in weapons and reactors.

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

In Popular Culture

In 2007 Andersen Press published 'The Yellowcake Conspiracy', a spy novel by British children's author Stephen Davies. The novel is about the trafficking of yellowcake in Niger.

References

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

See also

The Niger uranium forgeries refers to falsified classified documents initially revealed by Italian intelligence. These documents depict an attempt by the regime of Iraq's Saddam Hussein to purchase yellowcake uranium from Niger during the Iraq disarmament crisis.
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A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. A chemical formula is also a short way of showing how a chemical reaction occurs.
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In physics, density is mass m per unit volume V—how heavy something is compared to its size. A small, heavy object, such as a rock or a lump of lead, is denser than a lighter object of the same size or a larger object of the same weight, such as pieces of
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The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. Although the phrase would suggest a specific temperature and is commonly and incorrectly used as such in most textbooks and literature, most crystalline compounds
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standard state of a material is its state at 1 bar (100 kilopascals exactly). This pressure was changed from 1 atm (101.325 kilopascals) by IUPAC in 1990.[1] The standard state of a material can be defined at any given temperature, most commonly 25 degrees Celsius,
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Uranium (IPA: /jʊˈreɪniəm/)is a white/black metallic chemical element in the actinide series of the periodic table that has the symbol U and atomic number 92.
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Leaching is the process of extracting a substance from a solid by dissolving it in a liquid.

Agriculture

In agriculture, leaching may refer to the loss of water-soluble plant nutrients from the soil, due to rain and irrigation.
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ore is a volume of rock containing components or minerals in a mode of occurrence that renders it valuable for mining. An ore must contain materials that are
  • valuable
  • in concentrations that can be profitably mined, transported, milled, and processed.

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ACID (Atomicity, Consistency, Isolation, Durability) is a set of properties that guarantee that database transactions are processed reliably. In the context of databases, a single logical operation on the data is called a transaction.
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alkali (from Arabic: Al-Qalyالقلي, القالي ) is a basic, ionic salt of an alkali metal or alkaline earth metal element.
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A peroxide is a compound containing an oxygen-oxygen single bond. The simplest stable peroxide is hydrogen peroxide. Superoxides, dioxygenyls, ozones and ozonides compound are considered separately.
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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.
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Ammonium diuranate or (ADU) ((NH4)2U2O7), is one of the intermediate chemical forms of uranium produced during yellowcake production.
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Sodium diuranate, Na2U2O7·6H2O, is a uranium salt also known as the yellow oxide of uranium. Along with ammonium diuranate it was a component in early yellowcakes, the ratio of the two species determined by process conditions;
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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.
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Uranyl sulfate (UO2SO4) a sulfate of uranium presents as an odorless lemon-yellow sand-like solid in its pure crystalline form.

It has found use as a negative stain in microscopy and tracer in biology.
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Sodium uranate or Yellow uranium oxide, a uranium compound with the chemical fomula Na2O (UO3)2.6H2O is a yellow orange powder once used in pottery to produce ivory to yellow shades in glazes.
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Uranyl peroxide or Uranium peroxide hydrate (UO4·nH2O) is a pale-yellow, soluble peroxide of uranium. It is found present at one stage of the enriched uranium fuel cycle and in yellowcake prepared via the in situ
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Uranium oxide is an oxide of the element uranium.

The metal uranium forms several oxides:
  • Uranium dioxide or uranium(IV) oxide (UO2, the mineral Uraninite or pitchblende)
  • Uranium trioxide or uranium(VI) oxide (UO3)

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Triuranium octoxide (U3O8) is a compound of uranium. It presents as an olive green to black, odorless solid. In spite of its color, it is one of the more popular forms of yellowcake and is shipped between mills and refineries in this form.
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Uranium dioxide (UO2), an oxide of uranium, also known as urania or uranic oxide is a black, radioactive, crystalline powder. It occurs naturally in the mineral uraninite.
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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.
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UO2 pellets in zircaloy cladding.]]

The key components common to most types of nuclear power plants
  • Neutron moderator
  • Coolant
  • Control rods
  • Pressure vessel
  • Emergency Core Cooling Systems (ECCS)
  • Reactor Protective System (RPS)

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A pressurised heavy water reactor (PHWR) is a nuclear power reactor that uses unenriched natural uranium as its fuel and heavy water as its moderator (deuterium oxide D 2 O).
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Natural uranium (NU) refers to refined uranium with the same [isotopic ratio] as found in nature. It contains 0.7 % uranium-235, 99.3 % uranium-238, and a trace of uranium-234 by weight. In terms of the amount of radioactivity, approximately 2.2 % comes from uranium-235, 48.
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Enriched uranium is a sample of uranium in which the percent composition of uranium-235 has been increased through the process of isotope separation. Natural uranium is 99.284% 238U isotope, with 235U only constituting about 0.711 % of its weight.
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Uranium hexafluoride (UF6), referred to as "hex" in industry, is a compound used in the uranium enrichment process that produces fuel for nuclear reactors and nuclear weapons.
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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. This is the crucial process in the creation of a nuclear weapon.
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Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride, UF6, through semi-permeable membranes. This produces a slight separation between the molecules containing uranium-235 and uranium-238.
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The gas centrifuge is a hyper-centrifuge used to separate gases. Its most common use is to produce enriched uranium. For uranium enrichment it requires far less energy to achieve the same separation than the older gaseous diffusion process that it has mostly replaced.
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