The erosion of fused zirconium corundum brick is mainly divided into physical action and chemical action. Physical action refers to the glass melting furnace wall in the long-term operation process, repeatedly subjected to the impact of rapid cooling and rapid heat, the surface must undergo a contraction of the expansion of the change process. Due to excessive fatigue, the structure of fused zirconium corundum brick is damaged, resulting in increased surface cracks and loose structure. Therefore, under the action of air flow, material and glass liquid washing, cracking and peeling, and this process will be repeated.

The chemical action on the erosion of fused zirconium corundum brick is more complex and intense, which can be divided into four aspects:

1. Precipitation of glass phase

On the one hand, the glass phase in the brick will gradually melt and precipitate (the lowest precipitation temperature is about 1150 ℃). On the other hand, the alkaline glass liquid containing Na2O will intrude into the brick along the pores and cracks of the brick body, diffuse and permeate with the precipitated glass phase, thus reducing the viscosity and improving the fluidity of the precipitated glass liquid, thus intensifying the erosion behavior, and expand in depth.

2. Damaged skeleton

With the glass liquid to the depth of the erosion intensified, the composition of the brick skeleton minerals are gradually containing Na2O glass liquid infiltration, surrounded, the skeleton also began to be eroded. First, the dissolved mullite is decomposed into α-Al2O3 and SiO2, which in turn promotes the conversion of α-Al2O3 into β-Al2O3. With the increase of temperature, β-Al2O3 all dissolved in the glass liquid, the crystal lattice of the oblique zircon and corundum were also destroyed, and then fragmented, disintegrated and partially melted. β-Al2O3 gradually dissolves in the glass at high temperature and is rarely retained. With the continuous diffusion and penetration of the glass, the oblique zircon crystallites become free, and some of them are taken away with the glass liquid, which may become glass stones, and some are retained. Although the oblique zircon can be dissolved into the glass, but the solubility is very small, with the fluctuation of temperature, ZrO2 from the glass liquid rapid crystallization, the formation of skeleton or beaded oblique zircon crystals.

3. Crystalline analysis of new minerals

Because the skeleton mineral of the brick is partially melted in the glass liquid, the composition of the original glass liquid is changed. Therefore, when the ratio of SiO2-Al2O3-Na2O in the glass solution is close to the theoretical composition of nepheline, a large number of nepheline crystals are precipitated.

Al2O3 2SiO2 Na2O → 2 NaAlSiO4 (nepheline)

4. Invasion of nepheline

Since the density of the nepheline is less than the density of the brick body, the precipitation of the nepheline crystals is accompanied by a larger volume expansion, which makes the structure of the brick body loose. Although the melting of some crystalline phases in the brick will increase the viscosity of the glass liquid and have a certain bonding protection effect on the loose structure, it still cannot completely block the air flow, materials and glass liquid in the kiln and the effect of gravity, and crack and spall into the glass liquid to form glass stones. After peeling, the wound continues to be eroded and washed by the vitreous fluid and continues to peel off. The result will inevitably lead to the erosion and disintegration of fused zirconium corundum bricks.