Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2

Tetsuya Toba, Kouji Yasuda, Toshiyuki Nohira, Rika Hagiwara, Koki Ichitsubo, Kenta Masuda, Takayuki Homma

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    2 Citations (Scopus)

    Abstract

    Direct electrolytic reduction of powdery SiO2 has been investigated in molten CaCl2 at 1123 K aiming at a low cost and mass production of solar-grade Si. SiO2 powder was set on a Si plate which was installed at the bottom of the crucible and connected to a graphite rod used as a current lead. SiO2 powder was reduced to Si by cathodic polarization of the Si plate. The reduction rate was evaluated by the magnitude of the reduction current, in which three parameters were varied: electrode potential, SiO2 layer thickness, and SiO2 particle size. As a result, the ratedetermining step of the reduction is suggested to be the diffusion of O2- ions inside the reduced porous Si particles filled with the electrolyte. During the reduction process, however, other factors such as contact resistance between Si particles and porosity of SiO2 particles possibly influence the reduction rate.

    Original languageEnglish
    Title of host publicationECS Transactions
    Pages119-126
    Number of pages8
    Volume50
    Edition11
    DOIs
    Publication statusPublished - 2012
    Event18th International Symposium on Molten Salts and Ionic Liquids - 222nd ECS Meeting - Honolulu, HI
    Duration: 2012 Oct 72012 Oct 12

    Other

    Other18th International Symposium on Molten Salts and Ionic Liquids - 222nd ECS Meeting
    CityHonolulu, HI
    Period12/10/712/10/12

    Fingerprint

    Electrolytic reduction
    Molten materials
    Powders
    Cathodic polarization
    Crucibles
    Contact resistance
    Graphite
    Lead
    Porosity
    Particle size
    Electrolytes
    Electrodes
    Ions
    Costs

    ASJC Scopus subject areas

    • Engineering(all)

    Cite this

    Toba, T., Yasuda, K., Nohira, T., Hagiwara, R., Ichitsubo, K., Masuda, K., & Homma, T. (2012). Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2 In ECS Transactions (11 ed., Vol. 50, pp. 119-126) https://doi.org/10.1149/05011.0119ecst

    Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2 . / Toba, Tetsuya; Yasuda, Kouji; Nohira, Toshiyuki; Hagiwara, Rika; Ichitsubo, Koki; Masuda, Kenta; Homma, Takayuki.

    ECS Transactions. Vol. 50 11. ed. 2012. p. 119-126.

    Research output: Chapter in Book/Report/Conference proceedingConference contribution

    Toba, T, Yasuda, K, Nohira, T, Hagiwara, R, Ichitsubo, K, Masuda, K & Homma, T 2012, Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2 in ECS Transactions. 11 edn, vol. 50, pp. 119-126, 18th International Symposium on Molten Salts and Ionic Liquids - 222nd ECS Meeting, Honolulu, HI, 12/10/7. https://doi.org/10.1149/05011.0119ecst
    Toba T, Yasuda K, Nohira T, Hagiwara R, Ichitsubo K, Masuda K et al. Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2 In ECS Transactions. 11 ed. Vol. 50. 2012. p. 119-126 https://doi.org/10.1149/05011.0119ecst
    Toba, Tetsuya ; Yasuda, Kouji ; Nohira, Toshiyuki ; Hagiwara, Rika ; Ichitsubo, Koki ; Masuda, Kenta ; Homma, Takayuki. / Fundamental study on reduction rate for electrolytic reduction of SiO 2 powder in molten CaCl2 ECS Transactions. Vol. 50 11. ed. 2012. pp. 119-126
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    abstract = "Direct electrolytic reduction of powdery SiO2 has been investigated in molten CaCl2 at 1123 K aiming at a low cost and mass production of solar-grade Si. SiO2 powder was set on a Si plate which was installed at the bottom of the crucible and connected to a graphite rod used as a current lead. SiO2 powder was reduced to Si by cathodic polarization of the Si plate. The reduction rate was evaluated by the magnitude of the reduction current, in which three parameters were varied: electrode potential, SiO2 layer thickness, and SiO2 particle size. As a result, the ratedetermining step of the reduction is suggested to be the diffusion of O2- ions inside the reduced porous Si particles filled with the electrolyte. During the reduction process, however, other factors such as contact resistance between Si particles and porosity of SiO2 particles possibly influence the reduction rate.",
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    AU - Masuda, Kenta

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