Performance Analysis Of Corundum Brick

1. Fire resistance performance of corundum brick
According to the Al2O3-Cr2O3 binary phase diagram, Al2O3 and Cr2O3 can form a continuous solid solution without the formation of eutectic materials. Therefore, adding Cr2O3 to high-purity corundum materials, regardless of the amount added, not only does not reduce the refractory performance of the material, but also improves its refractory performance. The refractoriness (>1790 ℃) and load softening temperature (>1700 ℃) of chromium corundum bricks are superior to high-purity corundum products.
Strength of 2 Corundum Bricks
The room temperature compressive strength of high-purity corundum bricks is generally 70-100MPa, while the room temperature compressive strength of high-performance chromium corundum bricks is generally>150MPa, which is significantly higher than that of corundum bricks. This is because during the firing process of the product, Al2O3 Cr2O3 solid solution is formed between particles, between particles and fine powders, and between fine powders. This solid solution acts as a bridge connecting particles and fine powders together, greatly improving the strength of the material.
3 Thermal shock stability
According to data reports, when Cr2O3 is added to corundum and the content of Cr2O3 is between 10% and 66%, the thermal shock stability of the material decreases with the increase of Cr2O3 content. That is, chromium corundum bricks with low Cr2O3 content have better thermal shock stability than those with high Cr2O3 content. The high-performance chromium corundum bricks promoted and applied in our factory have a Cr2O3 content between 12% and 20%, and their thermal shock stability is improved compared to corundum bricks; Especially the AKZ type chromium corundum bricks produced by adding a small amount of phase changing additives have better thermal shock stability.
4. Anti slag erosion ability
The solubility of various refractory oxides in molten coal slag: The solubility of Cr2O3 in gasification slag (SiO2 CaO system) and various glass melts is much lower than that of other oxide materials. Therefore, Cr2O3 or refractory materials containing Cr2O3 have good resistance to steel slag, non-ferrous smelting slag, coal gasification slag, oil gasification slag, and various glass melt erosion. The viscosity of the liquid phase generated by the reaction between Cr2O3 melt or Cr2O3 and slag is higher than that of other low melting materials, which prevents the slag from penetrating into the interior of the brick along the capillary pores, avoiding the formation of a metamorphic layer and structural peeling.
The depth of erosion of chromium corundum bricks with different Cr2O3 contents by glass slag is different from that of corundum bricks. The experiment shows that when Cr2O3<17%, the higher the Cr2O3 content in the brick, the shallower the depth of glass slag intrusion.
In order to further investigate the erosion of corundum bricks and chromium corundum bricks by gasification furnace slag, slag resistance tests were conducted on gasification slag samples using crucible method at 1500 ℃. The results showed that corundum bricks were severely eroded by slag, and all slag penetrated into the bricks and penetrated to the surface along the internal pores of the bricks. The bricks turned brown with almost no slag residue; Chromium corundum bricks are almost not corroded by slag, and there is no obvious chemical reaction between slag and brick surface. The boundary between the inner hole edge and the residue is clear, and the slag penetrates very little into the brick. Only a metamorphic layer of about 5-10 mm thick is formed around the brick hole, and a large amount of slag remains in the crucible hole.
Through theoretical analysis and practical experience, it has been proven that chromium corundum bricks have better resistance to chemical erosion and permeability of gasification furnace slag than corundum bricks, and their resistance to structural peeling is also superior to corundum bricks.