Perlite refractory castables

Perlite refractory castables are generally made of Portland cement, CA-50 cement, water glass, aluminum phosphate and aluminum sulfate as binders. /m3; Well-expanded particles with particle size ≥0.05mm. When configuring high-strength perlite refractory castables, the bulk density of 300~500kg/m3; expanded perlite with a maximum particle size of about 5mm should be used as aggregate, and the particles of ≤0.05mm should not exceed 10%.

   With the increase of cement dosage, the bulk density increases, the strength increases, the thermal conductivity decreases, and the linear change after burning decreases. As the amount of cement increased, that is, the amount of perlite decreased, the amount of water was also decreased.

   An appropriate amount of fly ash float beads can improve the strength of the refractory castable, but the bulk density has increased and the thermal conductivity has increased slightly. Therefore, the varieties of expanded perlite refractory castables should be reasonably selected according to the use conditions of the kiln. For example, on the top of the rolling or forging steel heating furnace road, after pouring with clay or low-cement refractory castables, perlite refractory castables are used as insulation layers, and good energy-saving effects have been achieved.

   The general use temperature of perlite refractory castable is 600~900℃. Therefore, the use of Portland cement as the binder can fully meet the requirements of the kiln. The proportion of Portland cement perlite refractory castable is: No. 425 ordinary cement 40%, clay powder 16%, expanded perlite 44% and water 98%: its main performance is bulk density 0.48g/cm3; pressure resistance The strength is 1.0MPa and the thermal conductivity at 600℃ is 0.16W/(m·K).

   When preparing the perlite refractory castable, the perlite should be wetted with water before mixing, and the compression ratio of the remaining water-wet mixture should be 1.6~1.8 to ensure the bulk density of the refractory castable. After molding, natural curing should be carried out for 3 days. When the ambient temperature is higher than 25 ℃, wet curing is carried out after initial setting.