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  • 1 Korea Atomic Energy Research Institute, Daejeon, 305-353 Korea
  • 2 Department of Applied Chemical Engineering, Korea University of Technology and Education, Cheonan, 330-780 Korea
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Abstract  

In order to enhance the efficiency of pyrochemical technology, especially electrorefining process, physicochemical data of trivalent uranium in LiCl–KCl eutectic at 773 K were measured, including molar absorptivity, formal potential and diffusion coefficient of U3+ ions. The molar absorptivities of U3+ were determined to be 765 ± 48 and 686 ± 39 M−1 cm−1 at 465 and 550 nm, respectively. The formal potential of U3+/U4+ redox couple and diffusion coefficient of U3+ ions were measured to be −0.308 V vs. Ag/Ag+ and 8.7 × 10−6 M−1 cm−1, respectively. To elucidate the chemical behavior of U3+ ions under the existence of oxide ions, U3+ ions were reacted with oxides ions in situ produced at the LiCl–KCl media. Surprisingly, it was revealed from XRD patterns that UO2 was formed from the reaction between U3+ ions and O2− ions with the molar ratio of 1:1.