Uranyl carbonate

Uranyl carbonate, UO2(CO3), is a carbonate of uranium that forms the backbone of several uranyl mineral species such as andersonite, mckelveyite-(Y) and wyartite and most importantly rutherfordine. It is also found in both the mineral and organic fractions of coal and its fly ash and is the main component of uranium in mine tailing seepage water.

Uranium like other actinides readily forms a dioxide uranyl core (UO2). In the environment, this uranyl core readily complexes with carbonate to form charged complexes. Although uranium forms insoluble solids or adsorbs to mineral surfaces at alkaline pH it is these soluble carbonate complexes that increase its solubility, availability, and mobility with low affinities to soil. Uranium(VI) generally forms a pH-dependent suite of uranyl carbonate and various hydrated complexes in ground water solutions.

  • UO2(OH)2
  • UO2(CO3)22−
  • UO2(CO3)34−
  • UO2(CO3)(OH)3

A common method for concentrating uranium from a solution uses solutions of uranyl carbonates, which are passed through a resin bed where the complex ions are transferred to the resin by ion exchange with a negative ion like chloride. After build-up of the uranium complex on the resin, the uranium is eluted with a salt solution and the uranium is precipitated in another process.

Uranylcarbonate
Uranyl carbonate
Uranyl carbonate
Ball-and-stick model of the uranyl cation
Ball-and-stick model of the carbonate anion
Names
IUPAC name
Uranium carbonate
Other names
Uranium Carbonate
Identifiers
3D model (JSmol)
ChemSpider
Properties
UO2(CO3)
Molar mass 330 g/mol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).

The uranyl carbonate minerals

Uranyl carbonate complexes form a large class of mineral species. Several have been described in literature. These include:

  • Andersonite (hydrated sodium calcium uranyl carbonate)
  • Astrocyanite-(Ce) (hydrated copper cerium neodymium lanthanum praseodymium samarium calcium yttrium uranyl carbonate hydroxide)
  • Bayleyite (hydrated magnesium uranyl carbonate)
  • Bijvoetite-(Y) (hydrated yttrium dysprosium uranyl carbonate hydroxide)
  • Fontanite (hydrated calcium uranyl carbonate)
  • Grimselite (hydrated potassium sodium uranyl carbonate)
  • Joliotite (hydrated uranyl carbonate)
  • Liebigite (hydrated calcium uranyl carbonate)
  • Mckelveyite-(Y) (hydrated barium sodium calcium uranium yttrium carbonate)
  • Metazellerite (hydrated calcium uranyl carbonate)
  • Rabbittite (hydrated calcium magnesium uranyl carbonate hydroxide)
  • Roubaultite (copper uranyl carbonate oxide hydroxide)
  • Rutherfordine (uranyl carbonate)
  • Schröckingerite (hydrated sodium calcium uranyl sulfate carbonate fluoride)
  • Shabaite (hydrated copper cerium neodymium lanthanum praseodymium samarium calcium yttrium uranyl carbonate hydroxide)
  • Sharpite (hydrated calcium uranyl carbonate hydroxide)
  • Swartzite (hydrated calcium magnesium uranyl carbonate)
  • Voglite (hydrated calcium copper uranyl carbonate)
  • Wyartite (hydrated calcium uranyl carbonate hydroxide)
  • Widenmannite (lead uranyl carbonate)
  • Zellerite (hydrated calcium uranyl carbonate)
  • Znucalite (hydrated calcium zinc uranyl carbonate hydroxide)

References

  • "Radioactive Elements in Coal and Fly Ash: Abundance, Forms, and Environmental Significance" (PDF). Fact Sheet FS-163-97. U.S. Geological Survey. October 1997. Retrieved 22 November 2011.
  • "Ion-exchange". U.S. Nuclear Regulatory Commission. 6 October 2011. Retrieved 22 November 2011.
  • Flury, Markus; Harsh, James B. (2000). "Remediation of Uranium Contaminated Mine Waste" (PDF). State of Washington Water Research Center Report WRR-04. State of Washington Water Research Center. Retrieved 22 November 2011.
  • "The Uranyl Carbonates". Mineral Gallery. Amethyst Galleries. Retrieved 22 November 2011.
Ammonium uranyl carbonate

Ammonium uranyl carbonate (UO2CO3·2(NH4)2CO3) is known in the uranium processing industry as AUC and is also called uranyl ammonium carbonate. This compound is important as a component in the conversion process of uranium hexafluoride (UF6) to uranium dioxide (UO2). The ammonium uranyl carbonate is combined with steam and hydrogen at 500–600 °C to yield UO2. In another process aqueous uranyl nitrate, known as uranyl nitrate liquor (UNL) is treated with ammonium bicarbonate to form ammonium uranyl carbonate as a solid precipitate. This is separated from the solution, dried with methanol and then calcinated with hydrogen directly to UO2 to obtain a sinterable grade powder. The ex-AUC uranium dioxide powder is free-flowing, relatively coarse (10 µ) and porous with specific surface area in the range of 5 m2/g and suitable for direct pelletisation, avoiding the granulation step. Conversion to UO2 is often performed as the first stage of nuclear fuel fabrication.The AUC process is followed in South Korea and Argentina. In the AUC route, calcination, reduction and stabilization are simultaneously carried out in a vertical fluidized bed reactor. In most countries, sinterable grade UO2 powder for nuclear fuel is obtained by the ammonium diuranate (ADU) process, which requires several more steps.

Ammonium uranyl carbonate is also one of the many forms called yellowcake; in this case it is the product obtained by the heap leach process.

Andersonite

Andersonite, Na2Ca(UO2)(CO3)3·6H2O, or hydrated sodium calcium uranyl carbonate is a rare uranium carbonate mineral that was first described in 1948. Named after Charles Alfred Anderson (1902–1990) of the United States Geological Survey, who first described the mineral species, it is found in sandstone-hosted uranium deposits. It has a high vitreous to pearly luster and is fluorescent. Andersonite specimens will usually glow a bright lemon yellow (or green with blue hints depending on the deposit) in ultraviolet light. It is commonly found as translucent small rhombohedral crystals that have angles close to 90 degrees although its crystal system is nominally trigonal. Its Mohs hardness is 2.5, with an average specific gravity of 2.8.

It occurs in the oxidized zone of uranium-bearing polymetallic ore deposits. It also may occur as an efflorescent crust on the walls and timbers of uranium mines. As this mineral is water-soluble, samples must be stored in dry conditions. It occurs with schrockingerite, bayleyite, shwartzite, boltwoodite, liebigite and gypsum.It was first described in 1948 for an occurrence in the Hillside Mine near Bagdad, Eureka District, Yavapai County, Arizona.

Bijvoetite-(Y)

Bijvoetite-(Y) is a very rare rare-earth and uranium mineral with the formula (Y,REE)8(UO2)16(CO3)16O8(OH)8·39H2O. When compared to the original description, the formula of bijvoetite-(Y) was changed in curse of crystal structure redefinition. Bijvoetite-(Y) is an example of natural salts containing both uranium and yttrium, the other examples being kamotoite-(Y) and sejkoraite-(Y). Bijvoetite-(Y) comes from Shinkolobwe deposit in Republic of Congo, which is famous for rare uranium minerals. The other interesting rare-earth-bearing uranium mineral, associated with bijvoetite-(Y), is lepersonnite-(Gd).The mineral is named after the Dutch chemist and crystallographer Johannes Martin Bijvoet.

Braunerite

Braunerite is a hydrous uranyl carbonate mineral discovered by Jakub Plášil of the Institute of Physics at the Academy of Sciences of the Czech Republic and colleagues in the Svornost mine in the Jáchymov ore district, Western Bohemia, Czech Republic.Braunerite crystals are yellow and have a glassy luster. The mineral is chemically similar to línekite. The type material is deposited in the collections of the Department of Mineralogy and Petrology, National Museum, Prague, Czech Republic, and the mineralogical collections of the Natural History Museum of Los Angeles County.

Carbon Mineral Challenge

The Carbon Mineral Challenge is a citizen science project dedicated to accelerating the discovery of carbon-bearing minerals. The program launched in 2015 with sponsorship from the Deep Carbon Observatory. The project will end after 2019.

Corium (nuclear reactor)

Corium, also called fuel containing material (FCM) or lava-like fuel containing material (LFCM), is a lava-like material created in the core of a nuclear reactor during a meltdown accident.

It consists of a mixture of nuclear fuel, fission products, control rods, structural materials from the affected parts of the reactor, products of their chemical reaction with air, water and steam, and, in the event that the reactor vessel is breached, molten concrete from the floor of the reactor room.

Index of physics articles (A)

The index of physics articles is split into multiple pages due to its size.

To navigate by individual letter use the table of contents below.

Index of physics articles (U)

The index of physics articles is split into multiple pages due to its size.

To navigate by individual letter use the table of contents below.

Leószilárdite

Leószilárdite is a mineral discovered by Travis Olds of the University of Notre Dame and colleagues in the Markey Mine in Utah, USA. They named the mineral in honor of Leó Szilárd, Hungarian-born physicist and inventor. Leószilárdite is the first naturally occurring sodium- and magnesium-containing uranyl carbonate. It is rare and water-soluble, and was discovered on a seam of carbon-rich material deposited by an ancient stream. Groundwater reacted with the uraninite ore to create leószilárdite and other minerals.

List of inorganic compounds

Although most compounds are referred to by their IUPAC systematic names (following IUPAC nomenclature), "traditional" names have also been kept where they are in wide use or of significant historical interests.

List of minerals E (complete)

This list includes those recognised minerals beginning with the letter E. The International Mineralogical Association is the international group that recognises new minerals and new mineral names, however minerals discovered before 1959 did not go through the official naming procedure, although some minerals published previously have been either confirmed or discredited since that date. This list contains a mixture of mineral names that have been approved since 1959 and those mineral names believed to still refer to valid mineral species (these are called "grandfathered" species).

The list is divided into groups:

Introduction • (Main synonyms)

A • B • C • D • E • F • G • H • I • J • K • L • M • N • O • P–Q • R • S • T • U–V • W–X • Y–ZThe data was exported from mindat.org on 29 April 2005; updated up to 'IMA2018'.

The minerals are sorted by name, followed by the structural group (rruff.info/ima and ima-cnmnc by mineralienatlas.de, mainly) or chemical class (mindat.org and basics), the year of publication (if it's before of an IMA approval procedure), the IMA approval and the Nickel–Strunz code. The first link is to mindat.org, the second link is to webmineral.com, and the third is to the Handbook of Mineralogy (Mineralogical Society of America).

Abbreviations:

D – discredited (IMA/CNMNC status).

Q – questionable/ doubtful (IMA/CNMNC, mindat.org or mineralienatlas.de status).

N – published without approval of the IMA/CNMNC, or just not an IMA approved mineral but with some acceptance in the scientific community nowadays.

I – intermediate member of a solid-solution series.

H – hypothetical mineral (synthetic, anthropogenic, suspended approval procedure, etc.)

ch – incomplete description, hypothetical solid solution end member.

Rd – redefinition of ...

"s.p." – special procedure.

group – a name used to designate a group of species, sometimes only a mineral group name.

no – no link available.

IUPAC – chemical name.

Y: 1NNN – year of publication.

Y: old – known before publications were available.

List of minerals J (complete)

This list includes those recognised minerals beginning with the letter J. The International Mineralogical Association is the international group that recognises new minerals and new mineral names, however minerals discovered before 1959 did not go through the official naming procedure, although some minerals published previously have been either confirmed or discredited since that date. This list contains a mixture of mineral names that have been approved since 1959 and those mineral names believed to still refer to valid mineral species (these are called "grandfathered" species).

The list is divided into groups:

Introduction • (Main synonyms)

A • B • C • D • E • F • G • H • I • J • K • L • M • N • O • P–Q • R • S • T • U–V • W–X • Y–ZThe data was exported from mindat.org on 29 April 2005; updated up to 'IMA2018'.

The minerals are sorted by name, followed by the structural group (rruff.info/ima and ima-cnmnc by mineralienatlas.de, mainly) or chemical class (mindat.org and basics), the year of publication (if it's before of an IMA approval procedure), the IMA approval and the Nickel–Strunz code. The first link is to mindat.org, the second link is to webmineral.com, and the third is to the Handbook of Mineralogy (Mineralogical Society of America).

Abbreviations:

D – discredited (IMA/CNMNC status).

Q – questionable/ doubtful (IMA/CNMNC, mindat.org or mineralienatlas.de status).

N – published without approval of the IMA/CNMNC, or just not an IMA approved mineral but with some acceptance in the scientific community nowadays.

I – intermediate member of a solid-solution series.

H – hypothetical mineral (synthetic, anthropogenic, suspended approval procedure, etc.)

ch – incomplete description, hypothetical solid solution end member.

Rd – redefinition of ...

"s.p." – special procedure.

group – a name used to designate a group of species, sometimes only a mineral group name.

no – no link available.

IUPAC – chemical name.

Y: 1NNN – year of publication.

Y: old – known before publications were available.

List of minerals R (complete)

This list includes those recognised minerals beginning with the letter R. The International Mineralogical Association is the international group that recognises new minerals and new mineral names, however minerals discovered before 1959 did not go through the official naming procedure, although some minerals published previously have been either confirmed or discredited since that date. This list contains a mixture of mineral names that have been approved since 1959 and those mineral names believed to still refer to valid mineral species (these are called "grandfathered" species).

The list is divided into groups:

Introduction • (Main synonyms)

A • B • C • D • E • F • G • H • I • J • K • L • M • N • O • P–Q • R • S • T • U–V • W–X • Y–ZThe data was exported from mindat.org on 29 April 2005; updated up to 'IMA2018'.

The minerals are sorted by name, followed by the structural group (rruff.info/ima and ima-cnmnc by mineralienatlas.de, mainly) or chemical class (mindat.org and basics), the year of publication (if it's before of an IMA approval procedure), the IMA approval and the Nickel–Strunz code. The first link is to mindat.org, the second link is to webmineral.com, and the third is to the Handbook of Mineralogy (Mineralogical Society of America).

Abbreviations:

D – discredited (IMA/CNMNC status).

Q – questionable/ doubtful (IMA/CNMNC, mindat.org or mineralienatlas.de status).

N – published without approval of the IMA/CNMNC, or just not an IMA approved mineral but with some acceptance in the scientific community nowadays.

I – intermediate member of a solid-solution series.

H – hypothetical mineral (synthetic, anthropogenic, suspended approval procedure, etc.)

ch – incomplete description, hypothetical solid solution end member.

Rd – redefinition of ...

"s.p." – special procedure.

group – a name used to designate a group of species, sometimes only a mineral group name.

no – no link available.

IUPAC – chemical name.

Y: 1NNN – year of publication.

Y: old – known before publications were available.

Markeyite

Markeyite, a uranyl carbonate mineral discovered in the Markey Mine in Utah, USA. A group led by Anthony R. Kampf, a mineralogist at the Natural History Museum of Los Angeles County, USA discovered its structure.Cotype material for this mineral resides in the collections of the Natural History Museum, Los Angeles County, USA, and the Fersman Mineralogical Museum, Russian Academy of Sciences, Russia.

Rutherfordine

Rutherfordine is a mineral containing almost pure uranyl carbonate (UO2CO3). It crystallizes in the orthorhombic system in translucent lathlike, elongated, commonly radiating in fibrous, and in pulverulent, earthy to very fine-grained dense masses. It has a specific gravity of 5.7 and exhibits two directions of cleavage. It appears as brownish, brownish yellow, white, light brown orange, or light yellow fluorescent encrustations. It is also known as diderichite.

It was first described in 1906 for an occurrence in the Morogoro Region of Tanzania. It was named for Ernest Rutherford. It has been reported in the Democratic Republic of Congo, the Northern Territory of Australia and a variety of locations worldwide.It occurs as a secondary mineral as a weathering product of uraninite. In addition to uraninite it occurs associated with the rare minerals becquerelite, masuyite, schoepite, kasolite, curite, boltwoodite, vandendriesscheite, billietite, metatorbernite, fourmarierite, studtite and sklodowskite. It forms under acidic to neutral pH and is the only known mineral that contains only uranyl and carbonate.

Uranium

Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly radioactive because all isotopes of uranium are unstable; the half-lives of its naturally occurring isotopes range between 159,200 years and 4.5 billion years. The most common isotopes in natural uranium are uranium-238 (which has 146 neutrons and accounts for over 99% of uranium on Earth) and uranium-235 (which has 143 neutrons). Uranium has the highest atomic weight of the primordially occurring elements. Its density is about 70% higher than that of lead, and slightly lower than that of gold or tungsten. It occurs naturally in low concentrations of a few parts per million in soil, rock and water, and is commercially extracted from uranium-bearing minerals such as uraninite.In nature, uranium is found as uranium-238 (99.2739–99.2752%), uranium-235 (0.7198–0.7202%), and a very small amount of uranium-234 (0.0050–0.0059%). Uranium decays slowly by emitting an alpha particle. The half-life of uranium-238 is about 4.47 billion years and that of uranium-235 is 704 million years, making them useful in dating the age of the Earth.

Many contemporary uses of uranium exploit its unique nuclear properties. Uranium-235 is the only naturally occurring fissile isotope, which makes it widely used in nuclear power plants and nuclear weapons. However, because of the tiny amounts found in nature, uranium needs to undergo enrichment so that enough uranium-235 is present. Uranium-238 is fissionable by fast neutrons, and is fertile, meaning it can be transmuted to fissile plutonium-239 in a nuclear reactor. Another fissile isotope, uranium-233, can be produced from natural thorium and is also important in nuclear technology. Uranium-238 has a small probability for spontaneous fission or even induced fission with fast neutrons; uranium-235 and to a lesser degree uranium-233 have a much higher fission cross-section for slow neutrons. In sufficient concentration, these isotopes maintain a sustained nuclear chain reaction. This generates the heat in nuclear power reactors, and produces the fissile material for nuclear weapons. Depleted uranium (238U) is used in kinetic energy penetrators and armor plating. Uranium is used as a colorant in uranium glass, producing lemon yellow to green colors. Uranium glass fluoresces green in ultraviolet light. It was also used for tinting and shading in early photography.

The 1789 discovery of uranium in the mineral pitchblende is credited to Martin Heinrich Klaproth, who named the new element after the recently discovered planet Uranus. Eugène-Melchior Péligot was the first person to isolate the metal and its radioactive properties were discovered in 1896 by Henri Becquerel. Research by Otto Hahn, Lise Meitner, Enrico Fermi and others, such as J. Robert Oppenheimer starting in 1934 led to its use as a fuel in the nuclear power industry and in Little Boy, the first nuclear weapon used in war. An ensuing arms race during the Cold War between the United States and the Soviet Union produced tens of thousands of nuclear weapons that used uranium metal and uranium-derived plutonium-239. The security of those weapons and their fissile material following the breakup of the Soviet Union in 1991 is an ongoing concern for public health and safety. See Nuclear proliferation.

Uranium acid mine drainage

Uranium acid mine drainage refers to acidic water released from a uranium mining site using processes like underground mining and in-situ leaching. Underground, the ores are not as reactive due to isolation from atmospheric oxygen and water. When uranium ores are mined, the ores are crushed into a powdery substance, thus increasing surface area to easily extract uranium. The ores, along with nearby rocks, may also contain sulfide. Once exposed to the atmosphere, the powdered tailings react with atmospheric oxygen and water. After uranium extraction, sulfide minerals in uranium tailings facilitates the release of uranium radionuclides into the environment, which can undergo further radioactive decay while lowering the pH of a solution (Figure 1).

Uranyl sulfate

Uranyl sulfate (UO2SO4), a sulfate of uranium, is an odorless lemon-yellow sand-like solid in its pure crystalline form. It is prepared by dissolving UO3 in H2SO4.

It has found use as a negative stain in microscopy and tracer in biology. The Aqueous Homogeneous Reactor experiment, constructed in 1951, circulated a fuel composed of 565 grams of U-235 enriched to 14.7% in the form of uranyl sulfate.

The acid process of milling uranium ores involves precipitating uranyl sulfate from the pregnant leaching solution to produce the semi-refined product referred to as yellowcake.Radioactivity was discovered using potassium uranyl sulfate, K2UO2(SO4)2.

Znucalite

Znucalite or CaZn11(UO2)(CO3)3(OH)20·4(H2O) is a rare, radioactive, white to pale cream colored uranium-containing carbonate mineral, hydrated calcium zinc uranyl carbonate hydroxide. Znucalite crystallizes in the orthorhombic system, often forming aggregates or crusts, and is found as a rare secondary species in carbonate-hosted (meaning it is mined from carbonate containing formations such as limestone) polymetallic veins, and nearby oxidizing uranium veins; on dump material and coating mine walls, apparently of post-mine origin. It fluoresces yellow-green under UV light.It was first described in 1989, after being discovered in Lill Mine, Černojamské deposit (Black pits deposit) in the Czech Republic. It was named in 1990 by Petr Ondruš, František Veselovský, and R. Rybka for its constituent elements.

Uranium compounds
U(II)
U(III)
U(IV)
U(IV,V)
U(V)
U(V,VI)
U(VI)
U(XII)

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