LAUSR

Abstract The physicochemical properties of U(III) in molten salt in contact with ionic liquid and water were investigated to obtain better understandable information on the long-term storage of waste salt remaining from pyrochemical processing. UCl3 in LiCl-KCl eutectic melt was added into appropriate room-temperature ionic liquid and water, and determination of the oxidation state of uranium (U) in LiCl-KCl eutectic melt was achieved using spectroscopic methods. The addition of UCl3 in LiCl-KCl eutectic melt into the ionic liquid provided the same absorption spectrum as that obtained from the solvation of UCl3 by LiCl-KCl eutectic melt at 450 °C except for much less absorption peak intensities. The room-temperature ionic liquid of 1-hexyl-3-methyl-imidazolium chloride (HMICl) used in this research did not cause any oxidation or reduction of the U(III), as the other reported ionic liquids did. The U(III) in LiCl-KCl eutectic melt was stable in an HMICl ionic liquid and unstable in water.