The Role of Granule Size on the Kinetics of Electrochemical Reduction of SiO2 Granules in Molten CaCl2

Xiao Yang, Kouji Yasuda, Toshiyuki Nohira, Rika Hagiwara, Takayuki Homma

Research output: Contribution to journalArticlepeer-review

13 Citations (Scopus)

Abstract

As a fundamental study to develop a new process for producing solar-grade silicon, the effect of granule size on the kinetics of the electrochemical reduction of SiO2 granules in molten CaCl2 was investigated. SiO2 granules with different size ranges were electrolyzed in molten CaCl2 at 1123 K (850 °C). The reduction kinetics was evaluated on the basis of the growth rate of the reduced Si layer and the behavior of the current during electrolysis. The results indicated that finer SiO2 granules are more favorable for a high reduction rate because the contact resistance between the bottom Si plate and the reduced Si particles is small and the diffusion of O2− ions in CaCl2 inside the porous Si shell is easy. Electrolysis using SiO2 granules less than 0.1 mm in size maintained a current density of no less than 0.4 A cm−2 within 20 minutes, indicating that the electrochemical reduction of fine SiO2 granules in molten CaCl2 has the potential of becoming a high-yield production process for solar-grade silicon.

Original languageEnglish
Pages (from-to)788-797
Number of pages10
JournalMetallurgical and Materials Transactions B: Process Metallurgy and Materials Processing Science
Volume47
Issue number1
DOIs
Publication statusPublished - 2016 Feb 1

ASJC Scopus subject areas

  • Condensed Matter Physics
  • Mechanics of Materials
  • Metals and Alloys
  • Materials Chemistry

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