Corundum brick new process Refractory Materials Iron and steel smelting
Corundum brick refers to refractory material products with alumina content greater than 90% and corundum as the main crystalline phase. High compressive strength at room temperature (up to 340MPa). High initial softening temperature under load (> 1700℃). Good chemical stability, strong resistance to acid or alkaline slag, metal and glass liquid. The thermal shock stability is related to the microstructure. The corrosion resistance of compact products is good, but the thermal shock stability is poor.
1. Fire resistance of corundum brick
According to the binary phase diagram of Al2o3-Cr2O3,Al2O3 and Cr2O3 can form continuous solid solution without eutectic. Therefore, the addition of Cr2O3 in high purity corundum materials, no matter how much, not only will not reduce the fire resistance of the material, but improve the fire resistance of the material. Fire resistance of chrome corundum brick (& GT; 1790 ℃) and softening temperature under load (> 1700 ℃) are better than high purity corundum products.
2 strength of corundum brick
The compressive strength of high purity corundum brick is generally 70 ~ 100MPa at room temperature, while that of high performance chrome corundum brick is generally gt. 150MPa, its strength is obviously higher than corundum brick. This is due to the products in the process of firing, between the particles and particles, particles and fine powder, fine powder and fine powder between the formation of al2o3-Cr2O3 solid solution, the solid solution like bridge particles, fine powder connected together, so that the strength of the material greatly improved.
Thermal shock stability
It is reported that when Cr2O3 is added into corundum, the thermal shock stability of the material decreases with the increase of THE content of Cr2O3 when the content of Cr2O3 is 10% ~ 66%, that is, the thermal shock stability of the chrome corundum brick with low CONTENT of Cr2O3 is better than that of the chrome corundum brick with high content of Cr2O3. The Cr2O3 content of high performance chrome corundum brick is between 12% ~ 20%, and its thermal shock stability is higher than that of corundum brick. In particular, AKZ chrome corundum brick produced by adding a small amount of phase change additives has better thermal shock stability.
Slag erosion resistance
The solubility of various refractory oxides in molten cinder: The solubility of Cr2O3 in coal gasification slag (Sio2-cao system) and various glass melts is much smaller than the solubility of other oxide materials. Therefore, Cr2O3 or Cr2O3 containing refractories have good corrosion resistance of steel slag, non-ferrous smelting slag, coal gasification slag, petroliferous slag and various glass melts. Cr2O3 melt or Cr2O3 and slag reaction generated liquid viscosity than other low melt viscosity, which prevents the slag along the capillary pores to the internal infiltration of the brick body, to avoid the formation of metamorphic layer and the structure of spalling.