Influence of Kyanite Content on Microstructures and Properties of Castables Containing Spherical Lightweight Mullite Aggregates

摘要

Five lightweight mullite castables were prepared using the lightweight mullite aggregate (M45A) with narrow particle size distribution and spherical shape,mullite powder (M45P),kyanite powder,microsilica and Secar 71 cement as raw materials.After the specimens fired at 1 100 ℃,1 200 ℃ and 1 300 ℃ for 3 h,respectively,the effects of kyanite contents (8％,10％,12％,14％,16％ by mass) on the pbysical properties,phase composition and microstructures were investigated through an X-ray diffractometer (XRD),a scanning election microscopy (SEM) and a microscopy measurement method,etc.The results show that,for the specimens fired at 1 300 ℃ with the kyanite content from 8％ to 16％,the bulk densities and apparent porosities change little,but the cold modulus of rupture and the crushing strengths decrease significantly,and the linear change rates increase from-0.87％ to 0.64％.The most apposite mode is the specimen containing 12％ kyanite fired at 1 300 ℃,which has a high crushing strength of 29.3 MPa,a low linear change of 0.18％,an apparent porosity of 36.8％ and a bulk density of l.73 g/cm3.