Mullite Insulating Brick   The products are according to the international standard of production. They have low Fe2O3 content, good thermal shock resistance and low thermal conductivity. The products can supply for furnace lining or heat reserving layer of channel furnace, cracking furnace and shuttle furnace etc.   Properties   INDEX ITEMS     GJM23 GJM26 GJM28 GJM30 the Max. Service Temperature, ℃ 1260 1430 1540 1650 Volume Density ≤ 0.48 0.78 0.88 1.02 C.C.Strength, MPa 1.1 1.6 2.1 2.5 Bending Resistant Strength, MPa 0.9 1.4 1.8 2 the Linear Change after Reheating 24h % 0.5 0.5 0.5 0.5 Al2 O3 ,% ≥ 38.5 55 65 70 Fe2 O3 ,% ≤ 1.0 1.0 1.0 1.0 Thermal conductivity w/m· k 800 ℃ 0.18 0.31 0.36 0.41 Thermal conductivity w/m· k 1200℃ 0.35 0.41 0.46