Corrosion behavior of electrofused alumina-zirconia-silica (AZS) refractories in hydrogen-based direct reduction of iron: An experimental and thermodynamical investigation

Iron and steel production is a main source of CO 2 emissions worldwide. To meet global decarbonisation requirements, hydrogen-based direct reduction of iron ore is an essential approach. This transition raises new challenges for the refractory lining inside the shaft furnace. The current study therefore examines the behavior of the electrofused Alumina-Zirconia-Silica F50A refractory under pure H 2 and H 2 /H 2 O mixture, and compares it with high-grade sintered alumina refractory S99A, through thermogravimetric tests under various temperature and atmosphere conditions, and a 250 hours corrosion test under pure H 2 at 1200°C. X-ray diffraction and SEM analyses with elemental mapping allowed to better understand the involved corrosion mechanisms. The results demonstrate greater stability of F50A compared to S99A in both atmospheres, as well as a lower degradation rate in the presence of water vapor. Finally, linked with thermodynamic calculations, a reaction scheme in both atmospheres was presented for the promising electrofused AZS material F50A.