Corrosion behavior of alumina-carbon composite brick in typical blast furnace slag and iron

Abstract The corrosion behavior of alumina-carbon composite brick (ACCB) in CaO-8%MgO-14%Al2O3-SiO2 blast furnace slag and iron was investigated at different slag basicity and time via rotating immersion method. The results show that the erosion caused by slag is lightest and increases with the increase of basicity, while the slag and iron region is the most eroded area. The erosion caused by iron decreases with increasing basicity, and the whole erosion extent increases with time elapsing. The penetration of slag into ACCB is mainly appears on the boundary of corundum and mullite, while some unwashed-away high melting point phase like MgAl2O4 can mitigate the corrosion. The dissolution of carbon from ACCB into iron is one of the erosion reasons of ACCB, and the reaction between carbon and silica in ACCB can also be promoted by the appearance of iron. A synthetic action caused by slag and iron in this region leads to the worst erosion. And the reduction of SiO2 on the slag-iron interface relates the basicity of slag to the iron erosion degree.