Items Mullite M70 M60 M60 M45 Chemical,% Al2O3 68-73 56-60 58-62 42-46 SiO2 22-26 38-42 36-42 49-55 Fe2O3 ≤1.0 ≤0.5 ≤1.0 ≤1.0 K2O+NaO ≤0.3 ≤0.41 ≤0.3 ≤2.2 MgO - - - - CaO - - - - Bulk density g/cm3 ≥2.8 ≥2.6 ≥2.65 ≥2.55 Bibulous rate% ≤3 <4 <3 ≤2 Lord crystalling phase% 92 88 85 55