Corrosion of Corundum–MgAl2O4 Spinel-Based Castables in CaO–SiO2–Fe2O3–Al2O3-Based Slag at 1650 °C

Corundum–MgAl 2 O 4 spinel-based castables bonded with calcium aluminate cement (CAC) and hydratable alumina (HA) were studied to evaluate their performance as gas purging plugs in steel ladles. The thermomechanical properties and corrosion behavior of the as-prepared castables were investigated. The results indicate that the cold crushing strength and modulus of rupture of castables bonded with CAC and HA after firing at 1600 °C are in the same levels of 160 and 32 MPa, respectively. The sample bonded with HA showed lower permanent change of − 0.23 pct and slag infiltration index of 0.07 compared with CAC-bonded samples (> 0.34 pct and > 0.36, respectively), suggesting the better volume stability and corrosion and slag infiltration resistance to CaO–SiO 2 –Fe 2 O 3 –Al 2 O 3 -based slag of HA-bonded castable. The in situ -formed MgAl 2 O 4 spinel changed the corrosion and infiltration indices of CAC-bonded castable to 0.09 and 0.39, respectively, compared with castable without in situ MgAl 2 O 4 spinel, indicating that the corrosion resistance was improved but the infiltration resistance was reduced by the in situ -formed MgAl 2 O 4 spinel.