ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Fundamentals of High Temperature Processes
Viscosity of SiO2–CaO–Al2O3 Slag with Low Silica – Influence of CaO/Al2O3, SiO2/Al2O3 Ratio
Dimitrios SiafakasTaishi MatsushitaAnders Eric Wollmar JarforsShinya HakamadaMasahito Watanabe
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2018 Volume 58 Issue 12 Pages 2180-2185


The viscosity of low SiO2 (10–20 mass%)-CaO-Al2O3 slag system was measured in a wide temperature range (1623–2800 K) using the rotational bob method and the aerodynamic levitation method. The influence of SiO2/Al2O3 ratio and CaO/Al2O3 ratio on the viscosity was examined. It was concluded that the SiO2/Al2O3 ratio did not affect the degree of polymerization of the aluminosilicate network in the composition range of the present study. An abnormal behaviour of the viscosity was observed at a CaO/Al2O3 ratio of 1.57 which was attributed to the formation of 12CaO·7Al2O3-like clusters. It was concluded that the overall influence on the viscosity could be expressed as the summation of the influence from the aluminosilicate network and the influence from the cluster formation of the primary precipitating solid phase. The temperature dependence of the cluster formation was coupled to the driving force of precipitation of the 12CaO·7Al2O3 phase.

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© 2018 by The Iron and Steel Institute of Japan
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