Alumina Bubble are lightweight refractory materials produced by blowing high-purity alumina (Al₂O₃ ≥98%) at high temperatures. Characterized by a hollow core structure, they exhibit low density (0.5–1.5 g/cm³), excellent thermal insulation (thermal conductivity: 0.1–0.3 W/m·K), high-temperature resistance (≥1800°C), and strong thermal shock resistance. Widely used in aerospace, metallurgy, and petrochemical industries for kiln linings, they significantly reduce heat loss and enhance energy efficiency.