Alumina-magnesia spinel castable uses sintered/fused alumina-magnesia spinel and high-alumina aggregates as the main raw materials with low-cement or cement-free bonding. The main mineral phase is magnesia-alumina spinel (MgO·Al₂O₃). It has extremely strong resistance to alkaline slag and cement clinker erosion, and is the mainstream lining material for the burning and transition zones of cement rotary kilns.