Separation of Uranium and Lanthanides in a Fused Salt – Liquid Gallium Based Alloy System

This work presents a study of electrochemistry of uranium on a liquid gallium in LiCl-KCl eutectic by applying a series of electrochemical techniques. The electrochemical window of the Ga electrode in LiCl-KCl eutectic is about −1.40 to −0.35 V vs. Ag/AgCl. The reduction of U(III) on liquid gallium starts at −0.86 V and is a one step process with the transfer of three electrons. The co-reductive cyclic voltammograms of U(III) and Ga(III) present a couple of sharp redox peaks at about −0.95 and −0.84 V, corresponding to the formation and dissolution of the intermetallic compound UGa3. In addition, the reduction of Ga(III) in LiCl-KCl melt is a two-step process: Ga(III) → Ga(I) → Ga. The activity coefficient and solubility of U in liquid Ga at the temperature range from 673 to 823 K were determined by coulometric titration and open circuit potential respectively. The Gibbs free energy for the formation of UGa3 was also calculated. The intermetallic compound UGa3 was deposited by potentiostatic electrolysis at −1.0 V in the LiCl-KCl -GaCl3-UCl3 and LiCl-KCl-UCl3 melt on solid W and liquid Ga electrodes at 773 K, respectively. The electrolysis efficiency is about 97% based on the ICP result. Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) and X-ray diffraction (XRD) characterizations further identified the formation of UGa3.

Section: Activity Coefficients and Solubility Of U In Liquid Ga At 77...mentioning

confidence: 99%

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confidence: 99%

Electrochemical Properties of Uranium on the Liquid Gallium Electrode in LiCl-KCl Eutectic

Liu

Tang

Pang

et al. 2016

“…Although the separation of fission elements on liquid electrodes is very effective and promising, there have been only few studies on the separation by using liquid indium electrodes. 16,17,24,[38][39][40][41] The goal of this manuscript is to study the principal thermodynamic properties of cerium and uranium in molten 3LiCl-2KCl eutectic, solubility of cerium in liquid indium and the separation factor (SF) of U/Ce couple.…”

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confidence: 99%

Thermodynamics, Solubility and the Separation of Uranium from Cerium in Molten In/3LiCl-2KCl System

Xu¹,

Smolenski²,

Liu³

et al. 2020

The purpose of this work is to study the electrochemical behavior of uranium and cerium in fused In/3LiCl-2KCl system in the temperature range of 723-823 K by open-circuit potentiometry. The apparent electrode potential of Ce 3+ /Ce (U 4+ /U) couples and apparent standard potential of Ce-In (U-In) alloys vs AgCl/Ag reference electrode were established. The principal thermodynamic properties, activity and solubility of cerium and uranium were determined. The separation factor of uranium/cerium couple on liquid indium electrode was calculated. The experimental results have been shown that a lower temperature should be more effective for the separation uranium from cerium.

“…The separation coefficients of An from Ln in the Ga media are even several orders of magnitude higher than that on any other low melting metals, such as Zn, Bi, Cd, In etc. 31,32 The thermodynamic properties of Ln on the liquid Ga-based media = These authors contributed equally to this work. z E-mail: shiwq@ihep.ac.cn have been explored for reductive chemical extraction in melt.…”

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confidence: 99%

“…z E-mail: shiwq@ihep.ac.cn have been explored for reductive chemical extraction in melt. 31,32 In our previous work, we have investigated the electrochemical behaviors of uranium on the liquid Ga electrode. 33 However, a systematic study toward the electrochemical behaviors and extraction of Ln on the liquid Ga electrode in LiCl-KCl melt, although being obviously of scientific significance, as far as we know, has been lacking.…”

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confidence: 99%

Electrochemical Properties of Lanthanum on the Liquid Gallium Electrode in LiCl-KCl Eutectic

Pang¹,

Liu²,

Nie³

et al. 2016

This work presents an electrochemical study of La(III) in the LiCl-KCl-LaCl 3 melt on a liquid gallium electrode. The reduction of the La(III) on a liquid gallium starts at −1.13 V (vs. Ag/AgCl) and is a one step process with three electrons transferred. The activities, activity coefficients and solubilities of La in La-Ga alloys were calculated by open circuit potential technique at the temperature range of 673 to 823 K. Moreover, galvanodynamic methods was also applied on a W electrode to evaluate the apparent standard potential of La(III)/La couple, the Gibbs free energy for the formation of LaCl 3 and the activity coefficient of La(III) in the LiCl-KCl-LaCl 3 melt. The co-reductive cyclic voltammograms of La(III) and Ga(III) present several redox couples which correspond to the formation and dissolution of different La-Ga intermetallic compounds. Finally, potentiostatic electrolysis was employed to deposit La on a liquid Ga electrode and the intermetallic compound LaGa 6 was identified by Scanning Electron Microscopy coupled with Energy Dispersive Spectroscopy (SEM-EDS) and X-ray diffraction (XRD) characterizations.