High‐Strength Quasi‐Tabular Corundum Refractory Material Sintered From γ‐Al ₂ O ₃ and Activated Limestone at 1650°C

ABSTRACT Within the industry of plate‐shaped corundum advanced refractory industry, firing temperatures are concentrated around 1900°C. Due to the interwoven structure of plate‐shaped crystals, the compressive strength of most plate‐shaped corundum exceeds 200 MPa. To reduce energy consumption, this study used γ‐Al ₂ O ₃ and activated modified limestone fine powder as raw materials. Sintering was conducted at 1600°C, 1650°C, and 1700°C to investigate the effects of modified limestone content and sintering temperature on the phase composition and properties of the composite material. The study revealed that with increasing reaction temperature, the bulk density and compressive strength of the composite phase material first increased and then decreased, while the apparent porosity continuously decreased. When the modified limestone content was 1.11 wt.%, the sintered product at 1650°C achieved a relatively favorable apparent porosity of 13.31%, a bulk density of 3.7 g/cm ³ , and a maximum compressive strength of 218.03 MPa. This enabled sintering at lower temperatures while maintaining properties comparable to plate‐like corundum. As the modified limestone content increased, the porosity of the product increased, while the bulk density decreased; the compressive strength generally remained high, and it is expected to be used as a lightweight, high‐temperature‐resistant thermal insulation material.