Comparison of Chemical Erosion and Permeability of Chrome Corundum Brick and Corundum Brick

Fire resistance of corundum brick：From the binary phase diagram of Al2O3 -Cr2O3, it can be seen that Al2O3 and Cr2O3 can form continuous solid solutions without the generation of eutectics. Therefore, the addition of Cr2O3 to high-purity corundum materials, regardless of the amount of addition, will not only reduce the fire resistance of the material, but will increase the fire resistance of the material. The chrome-corundum bricks have better fire resistance (> 1790 ℃) and softening temperature (> 1700 ℃) than high-purity corundum products.

 

Resistance to slag erosion：The solubility of various refractory oxides in molten coal slag: The solubility of Cr2O3 in coal gasification slag (SiO2-CaO series) and various glass melts is much smaller than the solubility of other oxide materials. Therefore, Cr2O3 or Cr2O3-containing refractories have good resistance to steel slag, non-ferrous smelting slag, coal gasification slag, oil and gas slag and various glass melt erosion capabilities. The viscosity of the liquid phase generated by the reaction of Cr2O3 melt or Cr2O3 with slag is higher than other low-melt viscosities, which prevents the slag from penetrating into the brick body along the capillary pores, and avoids the formation of metamorphic layers and structural spalling.

 

Corundum bricks with different Cr2O3 content and corundum bricks have different erosion depths by glass slag. The test 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 clarify the corrosion of corundum bricks and chrome corundum bricks by the slag of the gasifier, the slag resistance test performed at 1500 ℃ using the gasification slag sample by the crucible method showed that the corundum bricks were severely eroded by the slag, and all the slag Penetrates into the brick, and penetrates the surface along the pores inside the brick, the brick becomes brown with almost no slag residue; chrome corundum brick is hardly eroded by slag, there is no obvious chemical reaction between the slag and the brick surface, and the boundary between the inner hole edge and the residue is clear , The slag penetrates into the brick very little, and only about 5-10 mm thick metamorphic layer is formed around the brick hole, and a large amount of slag remains in the crucible hole.

 

Theoretical analysis and practice prove that the chrome corundum brick has better chemical erosion resistance and permeability than the slag of the gasification furnace, and has better resistance to structural spalling than the corundum brick.