关键词: 球形莫来石轻骨料;轻质莫来石浇注料;蓝晶石含量;显微结构;性能

Abstract: In order to improve the volume stability and microstructure of the lightweight mullite castables which used the spherical shape lightweight mullite(M45)as aggregates, five castables with different contents of kyanite(w =8%、10%、12%、14% and 16%)were prepared.The phase compositions, microstructures and physical properties of the specimens sintering at 1300 ℃ for 3 h were investigated through x-ray diffractometer(XRD),scanning election microscopy(SEM),etc.The results show that, for the specimens sintered at 1300 ℃, with the kyanite content increased from 8wt% to 16wt%, the strengths decreased significantly when the linear change rates increased from -0.87% to 0.64%, and the bonding between matrix and aggregate got better first and then got poor.The most apposite mode is the sample containing 12% kyanite, which had a bulk density of 1.73 g/cm3, an apparent porosity of 36.8%, a high crushing strength of 29.3 MPa, a low linear change rate of 0.18%, a thermal conductivity of 0.58 W/(m· K)at 800 ℃and a refractoriness under load(T0.6)of 1339 ℃.

Key words: spherical lightweight mullite aggregate;lightweight mullite castable;kyanite content;microstructure;property