Uranyl carbonate explained

Uranyl carbonate refers to the inorganic compound with the formula UO₂CO₃. Also known by its mineral name rutherfordine, this material consists of uranyl (UO₂²⁺) and carbonate (CO₃^2-). Like most uranyl salts, the compound is a polymeric, each uranium(VI) center being bonded to eight O atoms.^[1] Hydrolysis products of rutherfordine are 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.^[2]

Uranyl carbonates as a class of materials

Many uranyl carbonates exist, rutherfordine being the simplest stoichiometry. Most uranyl carbonates additional components including water and diverse anions and cations.^[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.

Uranyl carbonate minerals

Uranyl carbonates 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

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

Notes and References

1. Refinement of the Crystal Structure of Rutherfordine. Finch R J, Cooper M A, Hawthorne F C and Ewing R C.. 1999. Can. Mineral.. 37. 929–38.
2. 10.1016/0883-2927(91)90040-V. Uranium-series radionuclides in fluids and solids, Milk River aquifer, Alberta, Canada. 1991. Ivanovich. M.. Fröhlich. K.. Hendry. M.J.. Applied Geochemistry. 6. 4. 405–418. 1991ApGC....6..405I.
3. 10.1016/j.jssc.2004.07.050. Spectroscopic Characterization of Alkaline Earth Uranyl Carbonates. 2005. Amayri. Samer. Reich. Tobias. Arnold. Thuro. Geipel. Gerhard. Bernhard. Gert. Journal of Solid State Chemistry. 178. 2. 567–577. 2005JSSCh.178..567A.