Refractoriness
High-alumina bricks possess higher refractoriness than fireclay bricks or semi-silica bricks, reaching 1750–1790°C; they are classified as high-grade refractory materials.
Refractoriness under load
Due to their high Al₂O₃ content and low impurity levels-which result in minimal formation of low-melting glassy phases-high-alumina products exhibit a higher refractoriness under load than fireclay bricks. However, because the mullite crystals do not form an interlocking network structure, their refractoriness under load remains lower than that of silica bricks.
Slag resistance
With their high Al₂O₃ content, high-alumina bricks behave similarly to neutral refractory materials and can resist erosion by both acidic and basic slags. However, due to the presence of SiO₂, their resistance to basic slag is somewhat weaker than their resistance to acidic slag.