Effect of CaO/SiO<sub>2</sub> Ratio on Surface Tension of CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO Melts

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Author(s)

    • Sukenaga Sohei
    • Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University
    • Higo Tomoyuki
    • Department of Materials Science and Engineering, Kyushu University
    • Shibata Hiroyuki
    • Institute of Multidisciplinary Research for Advanced Materials (IMRAM), Tohoku University
    • Saito Noritaka
    • Department of Materials Science and Engineering, Kyushu University

Abstract

The effect of the CaO/SiO<sub>2</sub> molar ratio on the surface tension of calcium aluminosilicate melts containing magnesia (CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO) has been explored using a ring method at 1723–1823 K; the Al<sub>2</sub>O<sub>3</sub> and MgO contents were approximately 12 and 8 mol%, respectively. The CaO/SiO<sub>2</sub> molar ratio of the samples was varied in the range of 1.1–1.7. The surface tension of the CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–MgO system simultaneously increased upon increasing the CaO/SiO<sub>2</sub> molar ratio. The present data were compared with the surface tension of the binary calcium silicate (CaO–SiO<sub>2</sub>) and the ternary calcium aluminosilicate (CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>) melts reported in the literatures. The surface tension of the present CaO–SiO<sub>2</sub>–Al<sub>2</sub>O<sub>3</sub>–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.

Journal

  • ISIJ International

    ISIJ International 55(6), 1299-1304, 2015

    The Iron and Steel Institute of Japan

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