Influence of Some Factors upon Electrodeposition of Liquid Li and Mg

Takenaka, Tohru; Shigeta, K.; Masuhama, Hiroshi; Kubota, Kazushi

doi:10.1149/1.3159348

Cited by 9 publications

(5 citation statements)

References 3 publications

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“…Evidence of the presence of elemental lithium in the electrolyte during the electrolytic reduction process includes the coloring of the molten salt from the formation of "metal fog", dark purple ribbons in the relatively transparent LiCl-Li 2 O solution, and the bubbling of salt samples upon contact with water. 115,[117][118][119] These observations, along with the low current efficiencies reported throughout the electrolytic reduction literature, are indicative of the presence of metal-salt solutions, and similar to the observations that led their study in the first half of the 20 th century. 89,90,92,94 As will be shown in the following examples, the generation of a complex LiCl-Li 2 O-Li electrolyte during the reduction of actinide oxides has significant implications regarding the oxide reduction process.…”

Section: Licl-li 2 O-li and The Reduction Of Actinide Oxidessupporting

confidence: 62%

“…115,[117][118][119] These observations, along with the low current efficiencies reported throughout the electrolytic reduction literature, are indicative of the presence of metal-salt solutions, and similar to the observations that led their study in the first half of the 20 th century. 89,90,92,94 As will be shown in the following examples, the generation of a complex LiCl-Li 2 O-Li electrolyte during the reduction of actinide oxides has significant implications regarding the oxide reduction process.…”

Section: Licl-li 2 O-li and The Reduction Of Actinide Oxidessupporting

confidence: 59%

“…This conclusion was recently stated in a review of molten salt electrolytic processes by Masset et al 114 Similar conclusions were reached during the studying "metal fog" formed during the electrolysis of lithium from LiCl-KCl where authors stated: "The metal fog generated in the Li electrolysis with larger cathodic current is hardly explained by simple dissolution". 115 This report further hypothesized that the phenomena observed could be explained by the formation of a salt soluble compound other than that of metallic lithium.…”

Section: -29mentioning

confidence: 82%

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Review—Metallic Lithium and the Reduction of Actinide Oxides

Merwin

Williamson

Willit

et al. 2017

J. Electrochem. Soc.

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Extensive research and process development has been conducted on the electrolytic reduction of actinide oxides in molten LiCl-Li 2 O. It is now accepted that the reduction of these metal oxides occurs via two separate reduction mechanisms: direct electro-chemical reduction and mediated chemical reduction by metallic lithium. The deposition of metallic lithium at the cathode (mediated chemical reduction mechanism) during the process is known to be essential in order to achieve high process throughputs and reduction yields, and yet a knowledge gap exists regarding the nature of metallic lithium in this system. This review summarizes the formation of lithium during the process and its dispersion into the molten salt electrolyte. Previously reported aspects of the physical chemistry of the LiCl-Li 2 O-Li system are presented with a specific focus on the dispersion of Li in the solution. Finally, issues regarding the effect of the presence of lithium on the electrolytic reduction process are discussed. Evidence shows that electrochemically generated metallic lithium is likely a significant source of experimental uncertainty, low current efficiency and Li 2 O consumption in the oxide reduction process. The reduction of uranium, plutonium and minor actinide oxides to a metallic form is an important nuclear fuel cycle process.2-9 The ability of metallic lithium to reduce various uranium oxides, importantly UO 2 and U 3 O 8 , has been known for many years.10 A molten salt metalothermic reduction process employing metallic lithium (Li) as a reductant dissolved in molten LiCl was first developed by Argonne National Laboratory (ANL) to consolidate a variety of forms of actinide oxides for integration into a single electrometallurgical reprocessing system. 11-13 An electrolytic process, often referred to as electro-deoxidation or simply oxide reduction, was subsequently developed as a more controllable method of reducing metal oxides. A feasibility study conducted by Poa et al. demonstrated that oxides of uranium and plutonium could be reduced electrochemically in molten salts as long as the reduction potential of the metal oxide in question was more noble than the cation of the electrolyte.14,15 This approach was further developed by Gourishankar et al. to better understand processes chemistry and develop the electrolytic cell technology. 13,[16][17][18][19][20] Independent research conducted by Fray, Farthing, and Chen (FFC) applied the principles of electrochemical reduction in molten salt electrolytes to a variety of metal oxide reduction processes. 21,22 The FFC process has been the subject of several literature reviews.23-25 While these review articles address the processes associated with the reduction of nuclear fuel in LiCl, they focus on the electro-deoxidation phenomena and the CaCl 2 -CaO system. Additionally, the process engineering of the electrolytic reduction of nuclear fuel, and experience in incorporating oxide fuel into pyroprocessing, has been the focus of a recent review article. 26 The current review wi...

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Section: Licl-li 2 O-li and The Reduction Of Actinide Oxidessupporting

confidence: 62%

Section: Licl-li 2 O-li and The Reduction Of Actinide Oxidessupporting

confidence: 59%

Section: -29mentioning

confidence: 82%

See 1 more Smart Citation

Review—Metallic Lithium and the Reduction of Actinide Oxides

Merwin

Williamson

Willit

et al. 2017

J. Electrochem. Soc.

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“…(3) dissolves in the CaCl 2 melt, because the solubility of Ca is reported as about 4 mol%Ca [13][14][15][16][17][18] . The droplets of Ca may be found as the metal fog near the cathode 19,20) , when Ca dissolution rate is delayed. This Ca-rich environment can be considered as a powerful reductant, even if it does not hold the highest chemical reactivity such as pure Ca.…”

Section: Reduction By Calciummentioning

confidence: 99%

Reduction of CaTiO<sub>3</sub> in Molten CaCl<sub>2</sub> - as Basic Understanding of Electrolysis

et al. 2017

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Electrochemical decomposition of CaTiO 3 at the cathode was examined in a scheme of titanium metal production from natural deposit, Ilmenite (TiFeO 3 ). Based on the possible precipitation of CaTiO 3 from TiFeO 3 , the electrochemical decomposition of CaTiO 3 is here examined using combination of the calciothermic reduction and the electrolysis of CaO in the same molten salt. Inhomogeneous reduction in the cathodic basket is related with buoyancy of Ca and insuf cient dehydration. By optimizing the cooling conditions, CaO content in the molten salt, and dehydration method, an industrial level of 0.42 mass%O could be achieved as powder form.

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“…Electrochemically deposited colloidal Me in molten salt has been considered to be particles formed by Me x molecular clusters 28–30 . Despite its importance, however, there is only limited knowledge about the behaviour of colloidal Me due to the difficulty of in-situ observation 31–37 . Recently, black filmlike colloidal Me was observed on an electrodeposited thin Li metal in molten LiCl-KCl 38 ; however, the detailed mechanism of colloidal Me flow has not been clarified.…”

Section: Introductionmentioning

confidence: 99%

Spontaneous colloidal metal network formation driven by molten salt electrolysis

Natsui

Sudo

Kaneko

et al. 2018

Sci Rep

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The molten salt-based direct reduction process for reactive solid metal outperforms traditional pyrometallurgical methods in energy efficiency. However, the simplity and rapidity of this process require a deeper understanding of the interfacial morphology in the vicinity of liquid metal deposited at the cathode. For the first time, here we report the time change of electrode surface on the sub-millisecond/micrometre scale in molten LiCl-CaCl2 at 823 K. When the potential was applied, liquid Li-Ca alloy droplets grew on the electrode, and the black colloidal metal moved on the electrode surface to form a network structure. The unit cell size of the network and the number density of droplets were found to depend on the applied potential. These results will provide important information about the microscale mixing action near the electrode, and accelerate the development of metallothermic reduction of oxides.

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Influence of Some Factors upon Electrodeposition of Liquid Li and Mg

Cited by 9 publications

References 3 publications

Review—Metallic Lithium and the Reduction of Actinide Oxides

Review—Metallic Lithium and the Reduction of Actinide Oxides

Reduction of CaTiO<sub>3</sub> in Molten CaCl<sub>2</sub> - as Basic Understanding of Electrolysis

Spontaneous colloidal metal network formation driven by molten salt electrolysis

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