There are many types of special binders for refractory castables. The following are some common types:
1. Cement binder
1• Aluminate cement: including CA-50, CA-70, etc., with fast hardening and high strength characteristics, suitable for rapid construction and occasions with high early strength requirements.
2• Portland cement: low cost, certain strength and durability, suitable for some ordinary refractory castables that do not require extremely high refractoriness.
2. Sol binder
1• Silica sol: can improve the density and high temperature performance of castables, widely used in amorphous refractory materials, and can improve the thermal shock resistance and erosion resistance of materials.
2• Alumina sol: high bonding strength, good high temperature stability, can make the castable obtain good room temperature strength and high temperature strength.
3. Phosphate binder
1• Aluminum dihydrogen phosphate: can form a stable bonding phase at medium and high temperatures, so that the castable has high strength and erosion resistance, often used in high temperature kilns and other refractory castables.
2•Sodium tripolyphosphate: It has good dispersibility and bonding properties, which can improve the fluidity and molding performance of the castable, and at the same time improve the strength of the material to a certain extent.
IV. Water glass binder
1•Sodium water glass: It has strong bonding ability, can make the castable quickly solidify and shape, has low cost, and is often used in some refractory castables that do not require high water resistance.
2•Potassium water glass: It has relatively good stability at high temperatures, which can improve the fire resistance and corrosion resistance of the castable.
V. Other binders
1•Phenolic resin: It has good bonding properties at room temperature, can make the castable obtain higher room temperature strength, can be carbonized at high temperature to form a carbon bonding phase, and improve the high temperature performance of the material.
2•Ultrapowder binder: Such as alumina powder, spinel powder, etc., can fill the pores of the castable, improve the density and strength, and improve the high temperature performance.
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