• Bulletin of the Chinese Ceramic Society
  • Vol. 42, Issue 2, 751 (2023)
SONG Shaohui1、2, LI Yawei1、2、3、*, LIAO Ning1、2, ZHANG Sisi1、2, LIU Wenjing1、2, LI Yueying3, and TIE Shengnian3
Author Affiliations
  • 1[in Chinese]
  • 2[in Chinese]
  • 3[in Chinese]
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    DOI: Cite this Article
    SONG Shaohui, LI Yawei, LIAO Ning, ZHANG Sisi, LIU Wenjing, LI Yueying, TIE Shengnian. Synthesis of Magnesium Silicate Hydrate Based on Bischofite and Its Application in Magnesia Castables[J]. Bulletin of the Chinese Ceramic Society, 2023, 42(2): 751 Copy Citation Text show less

    Abstract

    Bischofite is a very promising magnesium salt resource with abundant reserves and low cost. Magnesium silicate hydrate (M-S-H) gels with different MgO/SiO2 molar ratios (0.5∶1, 1∶1, 1.5∶1) were synthesized using bischofite from Qinghai Salt Lake and sodium silicate. The synthesis mechanism and structural characteristics of M-S-H were studied by XRD, SEM, infrared, and nuclear magnetic resonance tests. Then, the synthesized M-S-H was compounded with microsilica to prepare magnesia castable, and the influence of M-S-H structure on the bonding characteristics of castable was explored. The results show that M-S-H obtained from different MgO/SiO2 molar ratios exhibits a layered stacking structure. When the MgO/SiO2 molar ratio is 1∶1, the interlaminar free water is the least and the crystallinity is the highest. The synthesized M-S-H is used to replace part of microsilica to prepare magnesia castable, which significantly improves the mechanical properties of the castable after heat treatment at 1 550 ℃. The magnesia castable prepared with M-S-H (MgO/SiO2 molar ratio of 1∶1) and microsilica obtains the best comprehensive properties. Compared with the magnesia castable prepared by adding 6% (mass fraction) microsilica, the flexural strength at room temperature and high temperature increases by 75% and 8%, respectively.
    SONG Shaohui, LI Yawei, LIAO Ning, ZHANG Sisi, LIU Wenjing, LI Yueying, TIE Shengnian. Synthesis of Magnesium Silicate Hydrate Based on Bischofite and Its Application in Magnesia Castables[J]. Bulletin of the Chinese Ceramic Society, 2023, 42(2): 751
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