Effect of the calcining temperatures of low‐grade bauxite on the mechanical property of mullite ceramics

Abstract The mullite ceramics with excellent properties were prepared using traditional sintering method, and the starting material was low‐grade bauxite without any other additives in this paper. The variations in physical and chemical properties in the process of sintering, the specific surface area of calcined bauxite at different calcining temperatures, and the phase composition of the mullite ceramic and its microstructure were investigated by thermal analysis, laser particle analysis, the X‐ray diffraction, and scanning electron microscope, respectively. The effect of calcining temperatures of raw bauxite on mechanical property and sintering mechanism of mullite ceramic were explored and researched. The results showed that the flexural strength can reach 180 MPa, a great difference existed in mullite ceramics prepared from calcined bauxite at different calcining temperatures, and the sintering mechanism included densification of raw bauxite, the activities of calcined bauxite powders, and crystals in calcined bauxite.