Corrosion mechanism and behavior of nickel slag on semi‐rebonded magnesia‐chrome brick for top‐blown furnace

Abstract

The corrosion behavior and mechanism of nickel slag on semi‐rebonded magnesia‐chrome brick are investigated. The variations in the specimens before and after corrosion were studied using microstructure, phase composition, and thermodynamic simulations. The results reveal that at high temperatures, the metal oxides in nickel slag easily react with Cr₂O₃ to generate Cr‐spinel, and the isolation layer forms a continuous phase on the surface of the refractory. The appearance of the isolation layer causes the nickel slag corrosion process on semi‐rebonded magnesia‐chrome brick to shift from direct to indirect corrosion controlled by ion diffusion, effectively blocking the continuous penetration of Ca²⁺ and Si⁴⁺ in the slag inside the refractories. As a result, the semi‐rebonded magnesia‐chrome brick resists nickel slag corrosion extremely well.