A hollow spherical bulk refractory material. Common are alumina hollow spheres and zirconia hollow spheres. The former has an alumina content of over 99%, a fire resistance of close to 2000 ° C, a natural bulk density of 0.8 to 1.0 g / cm3, and low thermal conductivity. The latter has a content of zirconia and calcium oxide of> 99%, a fire resistance of more than 2400 ° C, and low thermal conductivity.
These two kinds of hollow spheres are high-temperature-resistant insulation materials, which can be used as raw materials for manufacturing thermal insulation products or directly used as bulk materials for the insulation layer of high-temperature kilns.
Alumina hollow sphere products use 70% alumina hollow spheres and 30% α-alumina fine powder as raw materials, and use aluminum sulfate solution as a binding agent to form a green body by vibration molding. After drying, use according to different situations High temperature firing or light firing products. It can be used as high-temperature furnace lining, back socks, furnace tubes, trays, protective covers, etc. that are in direct contact with the flame. Long-term use at 1800 ° C.
Zirconia hollow sphere products are 75% zirconia hollow spheres with different particle sizes, 25% zirconia fine powder, plus 4% calcium oxide fine powder as a stabilizer, and borax solution as a binder, after mixing, molding and drying Then, it is fired at a high temperature. It can be used as the lining of the ultra-high temperature furnace and the filler of the vacuum induction furnace, and the operating temperature can reach 2200 ℃.