Slag attack evaluation of in situ spinel-containing refractory castables via experimental tests and thermodynamic simulations

Although the in situ spinel formation in alumina–magnesia refractory castables induces an expansive behavior, many investigations highlight its positive role in the corrosion resistance of such materials. Thus, this work addresses the slag attack evaluation of four designed in situ spinel-containing castables (containing hydratable alumina or calcium aluminate cement as a binder source and 0 or 1 wt% of silica fume) when in contact with a FexO rich industrial slag. Corrosion cup-tests, microstructural characterization and a two-step thermodynamic simulation model were used in order to investigate the reactions taking place during the slag–refractory interactions. According to the attained results, hydratable alumina seems to be a suitable binder to improve the corrosion resistance of such castables, as it induces densification and the formation of an alumina-rich spinel phase at the slag–matrix interface. Moreover, the thermodynamic calculations matched to the experimental observations, attesting the efficiency of the proposed simulation model for the evaluation of the in situ spinel-containing castable corrosion behavior.