the influence of silica fume addition on properties of bauxite low-cement castables

In this study, the effect of silica fume addition, as an amorphous polymorph of sio2 with ultra-fine spherical particles, on microstructure, and mechanical properties of bauxite self–flowing low-cement castables was investigated. results show that the addition of 2 wt.% silica fume improved the properties of bauxite refractory castables. the use of silica fume led to the formation of the more amount of hibonite (cao·6al2o3) phase especially between the grain boundaries of the bauxite particles. cold crushing strength of the green and sintered castables increased which can be attributed to the lower porosity and the higher amount of hibonite phase.