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Effect of different SiO2 polymorphs on the reaction between SiO2 and SiC in Si production

Abstract

This work investigates the phase transformations in silica (SiO2) during heating to a target temperature between 1700 °C and 1900 °C and the effect of SiO2 polymorphs on the reduction reaction 2SiO2 + SiC = 3SiO + CO in silicon production. Different heating rates up to target temperature have been used to achieve the different compositions of quartz, amorphous silica and cristobalite. The different heating rates had a minor effect on the final composition, and longer time at temperatures > 1400 °C were necessary to achieve greater variations in the final composition. Heating above the melting temperature gave more amorphous silica and less cristobalite, as amorphous silica also may form from β-cristobalite. Isothermal furnace experiments were conducted to study the extent of the reduction reaction. This study did not find any significant difference in the effects of quartz, amorphous silica or cristobalite. Increased temperature from 1700 °C to 1900 °C increased the reaction rate.
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Category

Academic article

Language

English

Author(s)

  • Marit Buhaug Folstad
  • Eli Ringdalen
  • Halvard Tveit
  • Merete Tangstad

Affiliation

  • SINTEF Industry / Metal Production and Processing
  • Norwegian University of Science and Technology

Year

2021

Published in

Metallurgical and Materials Transactions B

ISSN

1073-5615

Volume

52B

Issue

2

Page(s)

792 - 803

View this publication at Norwegian Research Information Repository