Corrosion Behavior of Alumina Containing Refractory in Blast Furnace Hearth by CaO–SiO₂–MgO–Al₂O₃–Cr₂O₃ Slags

Abstract

The corrosion behaviors of corundum brick and carbon composite brick used in blast furnace hearth by CaO–SiO₂–MgO–Al₂O₃–Cr₂O₃(-CaF₂) slags were studied in the present work. The degradation of the corundum brick in slag was a result of slag infiltration and brick dissolution, and the corrosion of the brick became more serious with the addition of CaF₂ due to the decrease of slag viscosity. The disintegration of carbon composite brick in CaF₂-containing slag was caused by the combination of slag penetration, brick dissolution and reaction between slag and brick. By comparing the corrosion behavior in CaF₂-containing slag between the corundum brick and carbon composite brick, the corrosion degree of the corundum brick was greater than that of the carbon composite brick. To the blast furnace operation in which a low grade iron ore such as laterite ore and CaF₂ containing slag (about 2 wt%) are used, it was found that the carbon composite brick with better slag corrosion resistance can be selected as a hearth refractory so as to improve the operation performance and ensure the longer campaign life of blast furnace.