ISIJ International
Online ISSN : 1347-5460
Print ISSN : 0915-1559
ISSN-L : 0915-1559
Regular Article
Effect of CaO/SiO2 Ratio on Surface Tension of CaO–SiO2–Al2O3–MgO Melts
Sohei Sukenaga Tomoyuki HigoHiroyuki ShibataNoritaka SaitoKunihiko Nakashima
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2015 Volume 55 Issue 6 Pages 1299-1304


The effect of the CaO/SiO2 molar ratio on the surface tension of calcium aluminosilicate melts containing magnesia (CaO–SiO2–Al2O3–MgO) has been explored using a ring method at 1723–1823 K; the Al2O3 and MgO contents were approximately 12 and 8 mol%, respectively. The CaO/SiO2 molar ratio of the samples was varied in the range of 1.1–1.7. The surface tension of the CaO–SiO2–Al2O3–MgO system simultaneously increased upon increasing the CaO/SiO2 molar ratio. The present data were compared with the surface tension of the binary calcium silicate (CaO–SiO2) and the ternary calcium aluminosilicate (CaO–SiO2–Al2O3) melts reported in the literatures. The surface tension of the present CaO–SiO2–Al2O3–MgO melts was higher than those of the binary calcium silicate melts and slightly lower than those of the ternary calcium aluminosilicate melts when the polymerization degrees of the melts were comparable. The change in the surface tension was considered from the viewpoint of the local structure of oxygen atoms at the melt surface. Oxygen atoms, which require higher coordination by cations in the bulk, may tend to lose their neighbors at the surface of the melts, which can result in the formation of unsatisfied bonds at the surface. An increase in the number of unsatisfied bonds can yield an increase in the surface tension.

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© 2015 by The Iron and Steel Institute of Japan
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