ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Effects of MgO, Na2O, and B2O3 on the Viscosity and Structure of Cr2O3-bearing CaO–SiO2–Al2O3 Slags
Qiuhan LiShufeng YangYanling ZhangZhuoqing AnZhancheng Guo
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2017 Volume 57 Issue 4 Pages 689-696

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Abstract

The influence of MgO, Na2O, and B2O3 on the viscosity of Cr2O3 bearing CaO–SiO2–Al2O3 slags was investigated using the rotating cylinder method. Structural information of slags with different MgO, Na2O, and B2O3 content was obtained via Raman spectroscopy. The viscosity of Cr2O3 bearing CaO–SiO2–Al2O3–MgO slags increases with Cr2O3 addition. The viscosity and activation energy (Eµ) of Cr2O3 bearing CaO–SiO2–Al2O3 slags decreases with increased MgO, Na2O, and B2O3 content. The effect of MgO and B2O3 on viscosity and activation energy (Eµ) of Cr2O3 bearing CaO–SiO2–Al2O3 slags was greater than that of Na2O. This could be due to the different ways in which these additives modify the slag network structure. Raman spectroscopy analysis revealed that MgO and Na2O work as network modifiers, and the degree of polymerization (DOP) of slags increases with the addition of MgO and Na2O. MgO is more effective at modifying the structure than Na2O, because Na2O may be more likely to produce network former [AlO4] units. In this study, Cr2O3 and B2O3 are found to behave as network formers and increase the DOP. This is characterized by the decrease in NBO/Si (the number of non-bridging oxygen per Si atom) value. B2O3 addition leads to the formation of low melting point eutectics and weaker polymerization strength, which contribute to the decrease in slag viscosity.

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© 2017 by The Iron and Steel Institute of Japan
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