Study on the Corrosion Resistance Mechanism of High Corrosion Resistance Periclase Lanthanum Aluminate Bricks

The lining material of cement kilns used for collaborative disposal of waste incineration requires superior corrosion resistance. However, traditional hercynite brick often exhibit a decrease in corrosion resistance when used in the firing zone,which limits their widespread application in collaborative disposal of waste incineration in cement kilns. Both lanthanum aluminate and periclase have the advantages of high melting point and excellent chemical stability. In addition, lanthanum aluminate exhibits a low thermal expansion coefficient and superior resistance to slag erosion at high temperatures.Therefore, this article employs pre-synthesized composite magnesia lanthanum aluminate sand to replace hercynite raw material in the fabrication of highly corrosion resistant periclase lanthanum aluminate bricks and investigates their erosion resistance mechanisms. The following conclusion is drawn: introducing pre-synthesized composite magnesia lanthanum aluminate sand into magnesia refractory materials significantly enhances both room-temperature flexural strength and material densification. The La2O3 presentin multiphase magnesia based lanthanum aluminate sand can form a high melting point calcium lanthanum silicate phase with Si4+ and Ca2+ in cement clinker.This reaction simultaneously enhances the coating adhesion strength of magnesia-based refractories while reducing the corrosive effects of cement clinker on magnesia clinker. Furthermore, due to the superior alkali salt corrosion resistance of duplex magnesia based lanthanum aluminate sand compared to hercynite, its incorporation not only enhances the compactness of the sample but also effectively blocks pores suppresses alkali vapor diffusion through the formation of calcium lanthanum silicate phase. This significantly improves the corrosion resistance of magnesia-based refractories. Therefore,the periclase lanthanum aluminate brick prepared in the experiment can be used as a substitute for hercynite brick in cement kilns with waste co-processing, meeting the requirement for high corrosion resistance.