Improved slag corrosion resistance of MgO-C refractories with calcium magnesium aluminate aggregate and silicon carbide: Corrosion behavior and thermodynamic simulation

The influence of calcium magnesium aluminate (CMA) aggregate and silicon carbide on the slag corrosion resistance of MgO-C refractories was investigated by the induction furnace tests. The corrosion behavior and the formation of protective slag layer were also comprehensively discussed in present work. The results showed that CaAl2O4 in CMA converted into Al-containing liquid phase when facing the slag, while spinel with better slag corrosion resistance diffused into the refractory-slag interface. The Al-containing liquid phase melted from CaAl2O4 mixed with slag and increased the Al content, increasing the proportion of indirect dissolution, forming more spinel and decreasing the corrosion rate. Furthermore, the spinel and liquid slag formed solid-liquid mixture at the interface, increasing the viscosity and promoting the formation of protective slag layer, which avoided direct contact between slag and refractory. The combined use of CMA aggregate and silicon carbide showed better slag corrosion resistance because silicon carbide increased the oxidation resistance and inhibited the decarburized layer, while the FeSi alloy and higher viscosity also enhanced the slag corrosion resistance of such refractories.