Effect of the Al2O3/SiO2 mass ratio on the crystallization behavior of CaO-SiO2-MgO-Al2O3 slags using confocal laser scanning microscopy

Zhanjun Wang; Il Sohn

doi:10.1016/j.ceramint.2018.07.152

Effect of the Al₂O₃/SiO₂ mass ratio on the crystallization behavior of CaO-SiO₂-MgO-Al₂O₃ slags using confocal laser scanning microscopy

Zhanjun Wang, Il Sohn

Department of Materials Science and Engineering

Research output: Contribution to journal › Article › peer-review

31 Citations (Scopus)

Abstract

The crystallization behavior of a CaO-SiO₂-MgO-Al₂O₃ slag system with varying Al₂O₃/SiO₂ mass ratios from 0.03 to 1.10 has been investigated using a confocal laser scanning microscopy (CLSM). The resulting continuous cooling transformation (CCT) and time-temperature-transformation (TTT) curves showed that the initial crystallization temperature increased and the incubation time for crystallization slightly decreased with increasing Al₂O₃/SiO₂ ratio. The crystal growth rate first increased and then decreased with decreasing isothermal temperature. X-ray diffraction (XRD) analysis suggested that Ca₂MgSi₂O₇ or Ca₃MgSi₂O₈ precipitated as the primary phase at lower Al₂O₃/SiO₂ ratios, while the Ca₂Al₂SiO₇ phase was preferred at higher Al₂O₃/SiO₂ ratios. The observed crystalline phases correlated well with the expected thermodynamic predictions from FactSage. In addition, structural analysis using ²⁷Al magic angle spinning nuclear magnetic resonance (²⁷Al MAS-NMR) microscopy of the as-quenched slags indicated the presence of a higher ratio of tetrahedral [AlO₄]^5-structural units with increasing Al₂O₃/SiO₂ ratio, which enhanced the polymerization of tetrahedral [AlO₄]^5- and [SiO₄]^4- structural units to form Ca₂Al₂SiO₇.

Original language	English
Pages (from-to)	19268-19277
Number of pages	10
Journal	Ceramics International
Volume	44
Issue number	16
DOIs	https://doi.org/10.1016/j.ceramint.2018.07.152
Publication status	Published - 2018 Nov

Bibliographical note

Funding Information:
This work was supported by the Brain Korea 21 Plus Project and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning ( 2018R1A2B2006609 ).

Publisher Copyright:
© 2018 Elsevier Ltd and Techna Group S.r.l.

All Science Journal Classification (ASJC) codes

Electronic, Optical and Magnetic Materials
Ceramics and Composites
Process Chemistry and Technology
Surfaces, Coatings and Films
Materials Chemistry

Access to Document

10.1016/j.ceramint.2018.07.152

Cite this

@article{a399eaa14bf34d9b938f34a6853b6271,

title = "Effect of the Al2O3/SiO2 mass ratio on the crystallization behavior of CaO-SiO2-MgO-Al2O3 slags using confocal laser scanning microscopy",

abstract = "The crystallization behavior of a CaO-SiO2-MgO-Al2O3 slag system with varying Al2O3/SiO2 mass ratios from 0.03 to 1.10 has been investigated using a confocal laser scanning microscopy (CLSM). The resulting continuous cooling transformation (CCT) and time-temperature-transformation (TTT) curves showed that the initial crystallization temperature increased and the incubation time for crystallization slightly decreased with increasing Al2O3/SiO2 ratio. The crystal growth rate first increased and then decreased with decreasing isothermal temperature. X-ray diffraction (XRD) analysis suggested that Ca2MgSi2O7 or Ca3MgSi2O8 precipitated as the primary phase at lower Al2O3/SiO2 ratios, while the Ca2Al2SiO7 phase was preferred at higher Al2O3/SiO2 ratios. The observed crystalline phases correlated well with the expected thermodynamic predictions from FactSage. In addition, structural analysis using 27Al magic angle spinning nuclear magnetic resonance (27Al MAS-NMR) microscopy of the as-quenched slags indicated the presence of a higher ratio of tetrahedral [AlO4]5-structural units with increasing Al2O3/SiO2 ratio, which enhanced the polymerization of tetrahedral [AlO4]5- and [SiO4]4- structural units to form Ca2Al2SiO7.",

author = "Zhanjun Wang and Il Sohn",

note = "Funding Information: This work was supported by the Brain Korea 21 Plus Project and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning ( 2018R1A2B2006609 ). Publisher Copyright: {\textcopyright} 2018 Elsevier Ltd and Techna Group S.r.l.",

year = "2018",

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AU - Wang, Zhanjun

AU - Sohn, Il

N1 - Funding Information: This work was supported by the Brain Korea 21 Plus Project and Basic Science Research Program through the National Research Foundation of Korea (NRF) funded by the Ministry of Science, ICT & Future Planning ( 2018R1A2B2006609 ). Publisher Copyright: © 2018 Elsevier Ltd and Techna Group S.r.l.

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N2 - The crystallization behavior of a CaO-SiO2-MgO-Al2O3 slag system with varying Al2O3/SiO2 mass ratios from 0.03 to 1.10 has been investigated using a confocal laser scanning microscopy (CLSM). The resulting continuous cooling transformation (CCT) and time-temperature-transformation (TTT) curves showed that the initial crystallization temperature increased and the incubation time for crystallization slightly decreased with increasing Al2O3/SiO2 ratio. The crystal growth rate first increased and then decreased with decreasing isothermal temperature. X-ray diffraction (XRD) analysis suggested that Ca2MgSi2O7 or Ca3MgSi2O8 precipitated as the primary phase at lower Al2O3/SiO2 ratios, while the Ca2Al2SiO7 phase was preferred at higher Al2O3/SiO2 ratios. The observed crystalline phases correlated well with the expected thermodynamic predictions from FactSage. In addition, structural analysis using 27Al magic angle spinning nuclear magnetic resonance (27Al MAS-NMR) microscopy of the as-quenched slags indicated the presence of a higher ratio of tetrahedral [AlO4]5-structural units with increasing Al2O3/SiO2 ratio, which enhanced the polymerization of tetrahedral [AlO4]5- and [SiO4]4- structural units to form Ca2Al2SiO7.

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