Method for improving slag resistance of zircon brick

 
Zircon bricks have high fire resistance and softening point under load, low thermal expansion rate, and difficult to dissolve due to chemical attack by slag. However, their resistance to penetration (wetting resistance) is poor. Slag can penetrate the interior of the brick through pores. At the same time, it reacts with the decomposed zircon particles, forms a metamorphic layer, and causes the brick structure to collapse. In order to improve the use effect of zircon brick, the permeability of slag must be reduced, and the improvement method:
 
① The products with low porosity and permeability are made by adjusting the particle composition and changing the molding method, but the products made by this method will inevitably reduce the thermal shock stability;
 
② Add certain additives to the brick to increase the viscosity of the brick and slag interaction products. Clay combined with zircon stone bricks, the type and amount of clay used greatly affect the properties of the brick, the addition of clay will reduce the fire resistance of the product, which is due to the solvent effect of A1203 on zircon, in ZrO2-A1203 In the -SiO2 ternary system, the composition is ZrSi04 15%, A1203 15%, and SiO2 70% and the fused liquid phase is generated. Its melting point is 1610 ° C. As the firing temperature increases, the apparent pores of clay-zircon brick The decrease in the rate, the increase in air permeability, the increase in the number of coarse pores, the increase in compressive strength and high-temperature flexural strength, the erosion resistance of the product, and the thickness of the permeation layer increase.
 
When the combination of clay is not added, and the amount of zircon fine powder is changed, the test results of firing at 1500 ° C show that as the amount of zircon fine powder increases, the permeability decreases, the number of pores increases, and the product's corrosion resistance changes. When the amount of zircon fine powder is 60%, the thickness of the permeation layer is the thinnest.
 
From the above, it is known that in order to adjust the erosion resistance of the product, reduce the air permeability, improve the pore distribution and produce zircon products with strong impermeability, it must be considered in the process to adopt a suitable firing temperature and add an appropriate amount of zircon Stone fine powder and use a small amount of bound clay.