Chromium corundum refractory generally refers to the refractory material whose chromium oxide is less than 40‰ and the remaining component is alumina, which contains a small amount of impurities, and has the characteristics of high refractoriness, high hardness, excellent corrosion resistance, good thermal shock resistance and high wear resistance. Corundum refractories are widely used in coal water slurry pressurized gasifier lining, ladle refining furnace and carbon black reaction furnace lining, slag gasification furnace lining and glass melting furnace lining in petrochemical industry, etc. It can also be used as heating furnace Chromite corundum platform brick is an indispensable material for high temperature industry.
Both AL203 and Cr2O3 belong to corundum type structure, the radius of Cr3+ is 0.620Å, and the radius of AL3+ is 0.535Å. According to the empirical formula:
Since the difference between the ionic radii of Cr3+ and AL3+ is less than 15%, Cr ions can continuously and infinitely replace AL in the AL203 lattice, forming an infinitely continuous replacement solid solution.
The crystal structures of Cr203 and AL203 are the same, and the ionic radius differs by 13.7%. Therefore, Cr203 and AL203 can form an infinite solid solution at high temperature. From the liquid-solidus line, as the content of Cr203 increases, the temperature at which the liquid phase begins to appear also increases. Therefore, adding an appropriate amount of Cr203 to AL203 can significantly improve the mechanical properties and high-temperature performance of corundum-based refractories
Cr2O3 can form high melting point compounds or eutectics with higher melting temperature with many common oxides. For example, FeO·Cr203 spinel formed by Cr203 and Feo has a melting point of up to 2100 °C; Cr203 and AL203 can form a continuous solid solution. In addition, Cr203 can also greatly increase the viscosity of the slag and reduce the fluidity of the slag, thereby reducing the erosion of the slag to the refractory material. Therefore, adding an appropriate amount of Cr2O3 to the refractory material can significantly reduce the structural spalling of the furnace lining material caused by slag erosion. There is no obvious regularity between the corrosion ability of slag to chromium corundum refractories and the basicity of slag; when the basicity of slag is 2, the corrosion resistance of chromium corundum bricks is the best; when the basicity of slag is 0.2, copper The corrosion depth of slag to Chromite corundum brick is the smallest; when the basicity of slag is 0.35, the corrosion depth of tin slag to Chromite corundum brick is the smallest; when the basicity of lead slag is 0.3, the thickness of residue is the largest and the depth of reaction layer, erosion layer and penetration layer minimum. When the slag basicity is 0.37, the corrosion resistance of Chromite corundum bricks is the best. At 1400 °C, the corrosion resistance of Chromite corundum bricks to non-ferrous metal slag is: nickel slag > lead slag > copper slag > tin slag