Electrochemical Deposition with Redox Replacement of Lanthanum with Uranium in Molten LiCl-KCl

Abstract

Electrochemical recovery of dilute concentrations of actinides from spent nuclear fuel would reduce the longevity of storing high-level nuclear waste. Electrochemical deposition with redox replacement (EDRR) is used in a molten salt medium for the selective electrochemical recovery of uranium in the presence of excess concentrations of lanthanum. In each EDRR cycle, after a short electrodeposition pulse, the deposited lanthanum is spontaneously replaced by uranium at open circuit. After repeated cycles, uranium metal was obtained on a tungsten electrode immersed in LiCl-KCl melt that contained 1 wt.% lanthanum chloride – 0.15 wt.% uranium4+ chloride. Scanning electron microscopy and energy dispersive X-ray spectroscopy analysis revealed uranium particles approximately 0.5 - 1 μm with well-defined rectangular shapes; and with 20 – 60 times more uranium recovered on the surface of the electrode than lanthanum.

The Electrode Kinetics of UCl3 in LiCl-KCl Molten Salt

“…The study conducted by Eakin, which revealed that, within a limited electrolysis time, uranium would selectively deposit at the active site on the surface of the tungsten electrode and react with a portion of LiCl-KCl to form a monolayer of uranium. 47 Pseic studied the morphological changes of uranium metal on the electrode surface during potential scanning of CV, the SEM images of the surface of the tungsten electrode are shown in Fig. 5.…”

Density Measurements of Molten LiF–BeF2 and LiF–BeF2–LaF3 Salt Mixtures by Neutron Radiography

“…14 The higher solubility of lanthanides relative to that of actinides in chloride molten salts can be used to process spent nuclear fuel, as demonstrated in the chloride salt electrorefining process at Idaho National Laboratory. 15 Previously, solubilities of LaF 3 , CeF 3 , and SmF 3 in LiF− BeF 2 −UF 4 (62.8−36.4−0.8 mol %) salt as well as YF 3 and CeF 3 in NaF−BeF 2 (61−39 mol %) salt were measured to support MSRE. 16 Solubilities are also published for ARE salts, including the measurements of BaF 2 , LaF 3 , CeF 3 , SmF 3 , and YF 3 in NaF−ZrF 4 −UF 4 (50−46−4 mol %) salt.…”

“…These fission products affect neutronics and system operation through parasitic absorption of neutrons . The higher solubility of lanthanides relative to that of actinides in chloride molten salts can be used to process spent nuclear fuel, as demonstrated in the chloride salt electrorefining process at Idaho National Laboratory …”

“…14 The higher solubility of lanthanides relative to that of actinides in chloride molten salts can be used to process spent nuclear fuel, as demonstrated in the chloride salt electrorefining process at Idaho National Laboratory. 15 …”

Uranium electrodeposition at boron-doped diamond electrodes

“…Recent advancements in uranium electrodeposition, utilizing molten salts and covalent organic frameworks, have been demonstrated with various substrates, including Polyaniline/Graphite sheet, phytic acid-doped polypyrrole/carbon felt electrode, and tungsten electrodes [20]. Recently, investigations into the cathodic reduction of U(III) ions on inert (tungsten) and reactive (gallium, cadmium) electrodes were conducted at temperatures ranging from 623 K to 923 K using cyclic and square wave voltammetry [21].…”