Effects of MgO/Al ₂ O ₃ Molar Ratio on Properties and Crystallization of Cordierite Glass‐Ceramics Prepared From Industrial Solid Waste

ABSTRACT Cordierite glass‐ceramics have attracted much attention for their excellent properties. In this work, asbestos tailings, coal fly ash, and kaolin were used as raw materials. The MgO/Al 2 O 3 molar ratio (M/A ratio) and sintering temperature of raw materials were changed. The cordierite glass‐ceramics were prepared by melting water quenching and sintering method. X‐ray diffraction, scanning electron microscopy‐energy dispersive spectrometer, differential scanning calorimetry, and X‐ray photoelectron spectroscopy were used to investigate the microstructure and crystallization behavior of the glass‐ceramics. The physical and chemical properties of the glass‐ceramics were systematically evaluated. The results show that the crystallization process of glass‐ceramics is a combination of surface crystallization and bulk crystallization. A range of structural fragments in the base glass are transformed at a certain temperature and precipitated into crystal phases such as cordierite. Reducing the M/A ratio can promote the precipitation of cordierite phase and improve the acid–base resistance of glass‐ceramics. Increasing the M/A ratio helps to improve the densification of glass‐ceramics and thus improves the bending resistance. The cordierite glass‐ceramics prepared at the sintering temperature of 1170–1180°C and the M/A ratio of 1.4–1.8 showed the best comprehensive properties and met the requirement standard (JC/T 2097‐2011). Considering the specific needs of cordierite glass‐ceramics in different applications, the selection of glass‐ceramics materials with specific properties is the key to ensure that the performance indicators can be met. This study provides a feasible path for the resource utilization of industrial solid waste.