Chemical Composition: The brown firebricks are composed of various oxides, including Na2O (1.1%), MgO (1.5%), Al2O3 (16.0%), SiO2 (53.1%), SO3 (0.6%), K2O (4.0%), CaO (2.1%), TiO2 (1.4%), MnO (6.1%), Fe2O3 (11.8%), NiO (1.2%), and CuO (1.2%).

Physical & Mechanical Properties: The apparent density of the firebricks is 1.94 g/cm³, while the real density is 2.67 g/cm³. They have an open porosity of 27.24% and a water absorption rate of 14.02%. The cold crushing strength is measured at 17.45 MPa, and the flexural strength (M.O.R) is 2.61 MPa.

Thermal Properties: The refractoriness of the firebricks is greater than 1100°C, with a permanent linear change of less than 1%. Thermal conductivity is 0.88 W/m·K at 200°C and 0.90 W/m·K at 400°C. The heat capacity is 0.74 J/g·K. Thermal diffusivity is 6.1·10^-7 m/s at 200°C and 6.3·10^-7 m/s at 300°C.