Fireclay brick belongs to Al2O3-SiO2 series. its alumina content is at the range of 15～45﹪. These fireclay bricks are made from refractory clay and calcined clay (chamotte). Ordinary fireclay bricks are so cheap that they are widely applied in industrial furnaces. Special fireclay bricks have the characteristics of low porosity、high mechanical strength and good resistance to creep deformation .