Reaction Behavior and Mechanism of Uranium Metal With ZnCl₂ in LiCl-KCl Eutectic Molten Salt

In order to investigate the reaction process of using zinc chloride(ZnCl₂) and uranium metal to prepare the electrolytic refining initial molten salt system LiCl-KCl-UCl₃. In LiCl-KCl eutectic molten salt at 500 ℃, the thermodynamic calculation of the possible reaction was firstly carried out, the calculated results were used to determine the possible reaction path. The reaction process of uranium metal and zinc chloride was monitored by in-situ cyclic voltammetry and in-situ absorption spectroscopy. The color change of molten salt during the reaction was observed, and the change of element content in the sample was analyzed by ICP-MS. The reaction products were characterized by XRD and SEM-EDS. Summary all of them, the reaction behavior and reaction mechanism were finally determined. The results show that during the process of uranium metal and zinc chloride, Zn(Ⅱ) directly oxidizes uranium metal to U(Ⅲ), and the resulting Zn metal forms U-Zn alloy on the surface of the uranium metal. The process of initial molten salt system LiCl-KCl-UCl₃ prepared by zinc chloride and uranium metal reaches equilibrium within 240 min, the final mass fraction of Zn is maintained at 0.01%.