Effect of andalusite rich schist grain size and the addition of metallic aluminum powder on the properties of silica–alumina refractory

Refractory materials were elaborated from silica–alumina geomaterials related to granitoids and their direct surrounding rocks (kaolin clay and andalusite rich schist). The use of andalusite rich schist as aggregates (mean grain size: 1000–2000 μm) could improve the mechanical properties of synthesized refractory. The flexural strength increased from 39.10 to 54.16 MPa. The pyroscopic temperature increased from 1400 to 1450 °C. Thermal conductivity of the porous brick produced in this study (1.11 W/m K) showed 39% of reduction compared to initial brick of the same composition (1.83 W/m K). The thermal shock tests showed that the refractory samples have a good thermal shock resistance.