Corrosion of chemical-mineralogical gradient submicron-porous Al2O3-MgAl2O4 composite in contact with molten converter slag

• Published in: Journal of the European Ceramic Society 2023-09, Vol.43 (11), p.5044-5053
• Main Authors: Liu, Xuexin, Zhang, Jinhua, Wang, Jingran, Ni, Yue’e, Han, Bingqiang, Ke, Changming
• Format: Article
• Language: English
• Subjects: Converter slag; Gradient submicron-porous corundum-spinel composite; Penetration-corrosion resistances; Special submicron-pore structure
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/j.jeurceramsoc.2023.04.005

Penetration resistance and corrosion mechanism of a novel chemical-mineralogical gradient submicron-porous corundum-spinel composite (A90) to converter slag were investigated and compared to its dense corundum counterpart. Slag-penetration resistance of A90, due to its special submicron-pore structure, is superior to that of the corundum counterpart. Gradient Al2O3-rich spinels pre-embedded on the inner-surfaces of the pores are essential for making the slag deficient in Fe2+ and Fe3+ and CaO-rich. The resultant CaO-rich slag reacted with the corundum matrix of A90, building up a continuous dense layer composed of tightly interlocked highly refractory tabular CaA112O19 and thus suppressing the further slag penetration and corrosion. Due to the lack of MgO in the corundum/molten-slag reaction system, large amounts of low melting iron oxides still remained in the liquid slag, making it much less viscous, so it could penetrate readily the corundum substrate via the grain boundaries in it at the test temperature.