Comparative analysis on corrosion behavior of lightweight and dense mullite-corundum refractories: Role of Si-rich phase

The corrosion resistance of lightweight and dense mullite-corundum refractories to cement materials was examined. The specimens following static crucible treatment were investigated using phase analysis, microstructure, and thermodynamic simulation. The results reveal that diffusion of the silica-rich phase enhances alumina saturation solubility in the slag, reducing the corrosion resistance of the mullite-corundum refractories. The large proportion of closed pores and the continuous net-like structure of anorthite created by the corrosion reaction in the matrix, on the other hand, prevent further slag penetration into the lightweight mullite-corundum refractories. As a result, the presence of the silica-rich phase assures better slag penetration resistance of lightweight mullite-corundum refractories.