Do you know what erosion phenomena must exist in fused bricks?

Harmful components and erosion mechanisms in fused AZS bricks. Today Tianyang Refractory will introduce you in detail from the following two aspects.
 

1.Glass phase

The phase composition of the fused zirconium corundum refractory products is oblique zircon, corundum, a small amount of mullite, a glass phase and pores. In the process of manufacturing fused zirconium alumina bricks, in order to reduce and eliminate residual thermal stress, a certain amount of glass phase is required in the product as an absorbent to buffer thermal stress. However, due to the existence of the glass phase, it also brings some disadvantages. In terms of the resistance of the refractory to the liquid glass, the glass phase is a weak link. In the process of erosion, the glass phase is first precipitated and replaced with the high-temperature glass container, which accelerates the erosion of the crystal. Under high temperature use conditions, glass phase will also bleed out and accompany the release of air bubbles, which will contaminate the glass melt.

2.Carburizing

The carburization of zircon alumina fused brick products produced by general reduction methods is relatively serious. According to literature reports, the corresponding carbon content is judged by the color of the refractory section: light gray 0.03% ~ 0.06%, off-white <0.03%, gray 0.08% ~ 0.18%, dark gray

0.15% ~ 0.19%. Even products produced by advanced oxidation methods (long arc and oxygen blowing methods) contain some carbon (<0.01%). Carburizing occurs in the form of carbides, intercalated nitrides, sulfides, solid carbon, and residual reducing gases. When used under oxidizing conditions, gas is released, causing the phenomenon of glass phase exudation temperature to decrease. AZS brick contains more glass phase (33-usually about 20%), above 1100, will soften and exudate, and will increase the loss with the increase of temperature, the exudation of glass phase, and the carbon in the brick , Carbide, low-cost iron and titanium related impurities. When the kiln has an oxidizing atmosphere, oxygen diffuses to the brick body and reacts with these impurities to emit CO2, SO2 and other gases. These gases extrude the molten glass phase and form core bubbles on the surface. The crystal phase is lost due to the loss of the glass phase combination. This is the reason for the erosion of AZS bricks.