Air Hardening Refractory Castable

At present, the lightweight refractory castables for industrial kiln linings in the world all use hydraulic high-aluminum cement as the main binder. This material requires a long period of curing and drying time, so it cannot be put into production in time after casting. Since high-aluminum cement has a short shelf life, it is easy to cause quality problems. In addition, hydraulic castables have poor wear resistance and reduced strength under high temperature. Air-hardening lightweight refractory (heat-resistant) castables are used for industrial kiln linings and furnace linings that require corrosion resistance, wear resistance and fire resistance.

Air-hardening refractory castables only need to be naturally dried and cured, and do not need to be baked for a long time. The shelf life is more than one year, and the strength does not decrease under high temperature. In addition, air-hardening refractory castables are air-hardening (not water-hardening) lightweight heat-resistant refractory castables with good corrosion resistance and wear resistance.

Air-hardening refractory castables use lightweight high-strength ceramsite as the main raw material, and are appropriately formulated with alumina fine powder, floating beads, perlite and powdered sodium silicate, combined with clay, ultrafine powder and additives. When high-strength wear resistance is required, air-hardening refractory castables can use high-alumina aggregates and silicon carbide to partially or completely replace lightweight ceramsite. The Al2O3 content of medium-light alumina, high-alumina aggregates, and alumina fine powder should be greater than 50%. The additives can be selected from solid powders such as sodium tripolyphosphate and hexahydroxy resin, which are used together with sodium fluorosilicate. Ultrafine powder can be any of silica fume or αAl2O3. Air-hardening refractory castables use additives to modify powdered sodium silicate and fully disperse it with binding clay, ultrafine powder, etc., which acts as a composite solid binder, thereby improving various properties of the matrix.