Abstract: The single crystal phase mullite bricks were made by single crystal phase mullite as raw materials. By analyzing the physical and chemical indexes，phase composition and microstructure of single crystal mullite，it was found that single crystal mullite has dense structure and high stability.The physical and chemical properties and alkali corrosion resistance of single crystal mullite brick were tested，and the results were compared with those of anti-spalling high alumina brick and silicon mullite brick. It was found that single crystal mullite brick has the characteristics of low porosity，low bulk density，high refractoriness under load，high thermal shock resistance and excellent alkali corrosion resistance. The thermal conductivity of single crystal mullite brick at 1 000 ℃ is only 68% of that of anti-spalling high alumina brick and 52% of that of silicon mullite brick. It can replace high alumina brick and silicon mullite brick and be used in the medium and low temperature areas such as the preheating zone of cement kiln，safety zone and tertiary air duct

Key words: Cement kiln, Single crystal phase mullite, Alkali corrosion resistance, Bulk density, 　 　　　Thermal shock resistance, Thermal conductivity