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Cited by 64Molten salt chemistry and electrochemical processesMetallurgical Processes and ThermodynamicsIron and Steelmaking Processes

Interactions of molten salts with cathode products in the FFC Cambridge Process

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Chen, George Z.·2020·International Journal of Minerals, Metallurgy and Materials
DOI 10.1007/s12613-020-2202-1PMC PMC7772062
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Abstract

Molten salts play multiple important roles in the electrolysis of solid metal compounds, particularly oxides and sulfides, for the extraction of metals or alloys. Some of these roles are positive in assisting the extraction of metals, such as dissolving the oxide or sulfide anions, and transporting them to the anode for discharging, and offering the high temperature to lower the kinetic barrier to break the metal-oxygen or metal-sulfur bond. However, molten salts also have unfavorable effects, including electronic conductivity and significant capability of dissolving oxygen and carbon dioxide gases. In addition, although molten salts are relatively simple in terms of composition, physical properties, and decomposition reactions at inert electrodes, in comparison with aqueous electrolytes, the high temperatures of molten salts may promote unwanted electrode-electrolyte interactions. This article reviews briefly and selectively the research and development of the Fray-Farthing-Chen (FFC) Cambridge Process in the past two decades, focusing on observations, understanding, and solutions of various interactions between molten salts and cathodes at different reduction states, including perovskitization, non-wetting of molten salts on pure metals, carbon contamination of products, formation of oxychlorides and calcium intermetallic compounds, and oxygen transfer from the air to the cathode product mediated by oxide anions in the molten salt.

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  • MSE uses a molten salt, typically a chloride salt, as an electrolyte for metal oxides, and allows reduction of metal oxides from lunar regolith at temperatures ranging from 800-1000°C.

    “MSE uses a molten salt, typically a chloride salt, as an electrolyte for metal oxides.It allows for the reduction of metal oxides from lunar regolith at temperatures ranging from 800-1000 • C (Chen 2020; Mohandas and Fray 2004;Schwandt et al. 2012;Kilby et al. 2006;Jin et al. 2004;Jiang et al. 2006;Liu et al. 2017).”

    From A review and analysis of extraction methods for aluminum and oxygen from Lunar Regolith (2026) · cites this paper as Chen 2020

    The paper describes molten-salt electrolysis of solid metal oxides for metal extraction, and its References list examples using molten calcium chloride. The References also list studies of metal and oxygen production from lunar regolith, but the passages found do not establish the claimed 800–1000°C range for reducing lunar-regolith oxides. (LLM, conf=0.82)

    Experimental — accuracy not yet measured

  • For CaCl2, MSE operating temperature typically falls between 800°C and 1000°C.

    “For CaCl 2 , a commonly researched salt, this operating temperature typically falls between 800 • C and 1000 • C.”

    From A review and analysis of extraction methods for aluminum and oxygen from Lunar Regolith (2026) · cites this paper as Chen 2020

    The available overview says molten salts provide high temperatures for electrolysis but gives no operating range for CaCl2. Searches for 800°C, 1000°C, and CaCl2 operating temperature returned no passage establishing that 800–1000°C is typical; the temperature-bearing reference entry concerns a CaCl2–NaCl mixture at 550°C. (LLM, conf=0.71)

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Cited by

Sorted by citations

Authors
Chen, G. Z.
Affiliations
University of Nottingham Ningbo China (CN)
Corresponding author
Chen, George Z.
ORCID
Chen, George Z.
Venue
International Journal of Minerals, Metallurgy and Materials
Publisher
Springer Science and Business Media LLC
Published
2020-12
Volume
27
Issue
12
Pages
1572-1587
ISSN
  • 1005-8850 (ISSN-L)
  • 1674-4799
  • 1869-103X
DOI
10.1007/s12613-020-2202-1
PMC
PMC7772062
OpenAlex
W3090168637
Cited by
64
References
2
Citations by year
2026: 10 · 2025: 13 · 2024: 11 · 2023: 11 · 2022: 12 · 2021: 6 · 2020: 1
FWCI
3.56
Type
journal article
Language
en
Update notices
erratum (2021-03-11)
Open access
Licence
Locations
  • International Journal of Minerals Metallurgy and Materials (publishedVersion, cc-by)
  • PubMed Central (publishedVersion, cc-by)
  • Repository@Nottingham (University of Nottingham) (acceptedVersion, other-oa)
  • Repository@Nottingham (University of Nottingham) (submittedVersion, cc-by)
Funders
  • National Natural Science Foundation of China (2015-2019)
  • Ministry of Education of the People's Republic of China (2015-2019)
  • Engineering and Physical Sciences Research Council (EP/F026412/1, EP/J000582/1)
Topics
  • Physical Sciences › Chemical Engineering › Fluid Flow and Transfer Processes › Molten salt chemistry and electrochemical processes
  • Physical Sciences › Engineering › Mechanical Engineering › Metallurgical Processes and Thermodynamics
  • Physical Sciences › Engineering › Mechanical Engineering › Iron and Steelmaking Processes
Keywords
molten salts, FFC Cambridge process, metal oxide reduction, electrode-electrolyte interaction, carbon contamination, oxychlorides, oxygen transfer, solid oxide electrolysis, metal extraction

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