Water Glass Refractory Castable

Sodium silicate refractory castable is when the refractory castable is made, the binder selected is water glass instead of an unshaped refractory made of refractory cement or other binders.

The refractory castable combined with water glass has the characteristics of high strength, wear resistance, corrosion resistance and good thermal shock resistance. It is suitable for high temperature and thermal kiln equipment with special requirements.

There are many sources of aggregates and powders for water glass combined with castables, which can be used for aluminum silicate, siliceous, semi-silica, and magnesia, magnesia, aluminum and other refractory materials. Water glass is more viscous, and the stirring and shaking time increases. Sodium silicate can be mixed with refractory aggregates and powders. It is more convenient to use by adding water and stirring on site before pouring.

When the water glass combined with refractory castable is heated to 800-1000℃, the sodium fluoride and sodium oxide will melt, the amount of liquid phase increases, the effect of silica gel is weakened, and the load softening temperature is lower. At the same time, the use temperature of water glass combined with castable is relatively low. , The use temperature of high alumina refractory castable combined with water glass is 1400°C, the use temperature of clay and semi-silica is 1000°C, and the use temperature of magnesium is 1600°C. Therefore, the addition of water glass and sodium fluorosilicate should be minimized. Water glass combined with castables has high strength at room temperature, and the slight reduction in heating process is small, so it has high high temperature wear resistance.

Water glass combined with refractory castables in use: 1. The modulus, density and dosage of the water glass binder are important factors affecting the sodium silicate refractory castables (highaluminarefractory.com/high-alumina-refractory-castables/). From the hardening mechanism, it can be known that due to the adhesion, condensation and cohesion of the silicic acid gel, the refractory aggregate and the powder are cemented to obtain strength. Therefore, when there is sufficient sodium fluorosilicate, the modulus or density of the water glass solution increases, and a larger amount of silicic acid gel can be precipitated, thereby increasing the strength. When the amount of water glass increases, the pores of the molded body increase and the performance decreases. 2. In the sodium silicate refractory castable, when no accelerator is added, it needs heating to harden and obtain excellent performance, but there is one more heating and hardening process in the construction. Therefore, sodium fluorosilicate is generally used as a coagulant, which can be hardened by natural curing at room temperature and has good performance. When the basic mixing ratio is constant, with the increase in the amount of sodium fluorosilicate, the compressive strength at room temperature and after firing will increase, and the high temperature compressive strength at 700℃ will also increase, while the high temperature compressive strength at 900℃ will decrease. At the same time, the load softening temperature is reduced by 40℃ and the refractoriness is reduced by 120℃. This is due to the large amount of sodium fluorosilicate, the formation of silicic acid gel, and the sodium fluoride, which are beneficial to the improvement of certain properties; and 900℃ It melts from left to right, and there is more sodium fluoride, which reduces the compressive strength, softening temperature under load and refractoriness at 900℃. Therefore, under the condition of ensuring a certain strength at room temperature, add as little sodium fluorosilicate as possible.

In the production of water glass combined with refractory castables, the selected refractory aggregates and powders, the variety, dosage, particle gradation, and the use of refractory powder fineness and purity will have a certain impact on its performance. Water with high temperature performance Glass combined with refractory castables are scientifically formulated to provide high-quality lining castables for the furnace.