Uranium tetrachloride

Chembox new
Name = Uranium tetrachloride
ImageFile = UCl4.jpg
ImageName = Uranium Tetrachloride
IUPACName = Tetrachlorouranium
OtherNames = Uranium (IV) Chloride
Section1 = Chembox Identifiers
CASNo = 10026-10-5
Section2 = Chembox Properties
Formula = UCl₄
MolarMass = 379.84 g/mol
Solvent =
SolubleOther =
MeltingPt = 590°C
BoilingPt = 791°C
Section3 = Chembox Structure
CrystalStruct = Octahedral

Uranium tetrachloride (UCl₄) is a dark green compound of uranium. Uranium metal was first isolated (1841) by Eugène-Melchior Péligot by the reduction of uranium tetrachloride with potassium. Commercially uranium tetrachloride is produced by the reaction of carbon tetrachloride with pure uranium dioxide UO₂ at 370°C. It is radioactive and is soluble in water.

Uranium tetrachloride is used as feed in the electromagnetic isotope separation (EMIS) process of uranium enrichment. Beginning in 1944, the Oak Ridge Y-12 Plant converted UO₃ to UCl₄ feed for the for Ernest O. Lawrence’s Alpha Calutrons. Its major benefit being the uranium tetrachloride used in the calutrons is not as corrosive as the uranium hexafluoride used in most other enrichment technologies This process was abandoned in the 1950s. In the 1980s, however, Iraq unexpectedly revived this option as part of its nuclear weapons program. In the enrichment process, uranium tetrachloride is ionized into a uranium plasma.The uranium ions are then accelerated and passed through a strong magnetic field. After traveling along half of a circle the beam is split into a region nearer the outside wall which is depleted and a region nearer the inside wall which is enriched in U-235. The large amounts of energy required in maintaining the strong magnetic fields as well as the low recovery rates of the uranium feed material and slower more inconvenient facility operation make this an unlikely choice for large scale enrichment plants.

Work is being done in the use of molten uranium chloride-alkali chloride mixtures as reactor fuels in molten salt reactors. Uranium tetrachloride melts dissolved in a lithium chloride-potassium chloride eutectic have also be explored as a means to recover actinides from irradiated nuclear fuels through pyrochemical nuclear reprocessing.

References

* Reaction of chlorine and uranium tetrachloride in the fused lithium chloride-potassium chloride eutectic, Donald R. Olander, J. L. Camahort, Lawrence Radiation Laboratory and University of California, Berkeley, California
* The Militarily Critical Technologies List (MCTL),Part II: Weapons of Mass Destruction Technologies, U.S. Department of Defense, updated July 2003.
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