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Magnesiothermic Reduction of Natural Quartz

Abstract

In the current work, the metallothermic reduction of natural quartz by magnesium has been studied at 1373 K under different reaction conditions, i.e. quartz type, quartz particle size, Mg:SiO2 mole ratio and reaction time. The microstructure of reaction products was studied to illustrate the reaction progression through scanning and transmission electron microscopy techniques. X-ray diffraction analysis with Rietveld phase quantification was used to calculate the change in the amount of phases at different reaction conditions. The results showed that the
Mg:SiO2 mole ratio strongly affects reaction mechanism and product characteristics such as phase content and microstructure. At lower Mg:SiO2 mole ratios, the reaction rate is fast at the
beginning and the formation of a product layer consisting of different phases such as MgO, Si,
Mg2Si, Mg2SiO4 and MgSiO3 around quartz particles limits the Mg diffusion. This phenomenon
is more noticeable for larger quartz particle sizes where Mg should diffuse longer distance
towards the quartz core to react with it. At higher Mg:SiO2 mole ratios, a significant amount of
Si–Mg liquid alloy is formed during reaction where the high mobility of Mg in this liquid phase
and cracking of quartz particles result in significantly higher reaction rate. Here the formation of
intermediate phases is not significant and the products would be the mixture of MgO, Mg2Si,
and either Si or Mg phases.

Category

Academic article

Language

English

Author(s)

  • Azam Rasouli
  • Karl Edvin Herstad
  • Jafar Safarian
  • Gabriella Tranell

Affiliation

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

Year

2022

Published in

Metallurgical and Materials Transactions B

ISSN

1073-5615

Publisher

Springer

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