In order to separate uranium and iron in LiCl-KCl eutectic, the electrochemical behaviors of Fe2+ and \({\text{UO}}_{2}^{{2+}}\) , the influences of Fe2+ on electrochemical reduction mechanism of \({\text{UO}}_{2}^{{2+}}\) and nucleation mode of uranium dioxide were investigated by various electrochemical methods. Cyclic voltammetry (CV) and square wave voltammetry (SWV) results displayed that the reduction of Fe2+ to Fe through a one-step two electron process, while \({\text{UO}}_{2}^{{2+}}\) through a two-step single electron process. The reduction potential of Fe2+ was found to be more negative than that of \({\text{UO}}_{2}^{{2+}}\) . The reduction mechanism of \({\text{UO}}_{2}^{{2+}}\) was not affected by Fe2+. Meanwhile, the exchange current density (j0) of Fe2+/Fe on W electrode was estimated using polarization curve method. Using the linear relationship between lgj0 and 1/T, the activation energy was estimated to be 20.31 kJ mol− 1. The effects of Fe2+ on the mass transfer of \({\text{UO}}_{2}^{{2+}}\) and nucleation mode of uranium dioxide were explored. It was found that the nucleation mode of uranium dioxide was still the progressive nucleation. Moreover, \({\text{UO}}_{2}^{{2+}}\) and Fe2+ were electrochemically separated by constant potential at -0.3 V and different temperatures. The products characterized showed that UO2 was separated from Fe. The separation efficiencies of UO2 at 773 K and 823 K were estimated and found to be 56.43% and 65.44%, respectively.
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