Preparation and Properties Study of Lanthanum Modified Mullite

Mullite materials exhibit distinctive physical and chemical characteristics at elevated temperatures, making them key refractory materials in high-temperature applications. However, the cost of sintering mullite synthesis is extremely high, as it requires temperatures up to 1700 ℃.This not only results in significant energy consumption but also necessitates more stringent equipment specifications. The results of this study show that doping coal gangue raw material with La2O3 can significantly reduce the preparation temperature of mullite materials, effectively minimize quartz-phase impurities formed during the sintering process, and enhance the density of the resulting mullite. When the doping amount of La2O3 is 5% (mass fraction), the synthesis temperature of mullite can be reduced from 1700 ℃ to 1560 ℃, and the compressive strength of the modified material at 1200 ℃ reaches 27.3 MPa, the flexural strength is 8.1 MPa, and the coefficient of thermal expansion is 7.03×10-6. This study presents a novel approach for the low-temperature fabrication of high-quality mullite materials.