Excellent properties and uses of cenospheres: high refractoriness. The main chemical components of cenospheres are oxides of silicon and aluminum, of which silicon dioxide is about 50-65%, and aluminum oxide is about 25-35%. Because the melting point of silica is as high as 1725 degrees Celsius, the melting point of aluminum oxide is 2050 degrees Celsius, both of which are high refractory materials. Therefore, cenospheres have extremely high refractoriness, generally reaching 1600-1700 degrees Celsius, making them an excellent high-performance refractory material. Lightweight, thermal insulation. The wall of the cenospheres is thin and hollow, and the cavity is semi-vacuum, with only a very small amount of gas (N2, H2 and CO2, etc.), and the heat conduction is extremely slow and extremely small. Therefore, cenospheres are not only light in weight (bulk density 250-450 kg/m3), but also excellent in thermal insulation (thermal conductivity at room temperature 0.08-0.1), which lays the foundation for them to show their talents in the field of lightweight thermal insulation materials. High hardness and strength. Because the cenospheres are hard glass bodies formed by silicon aluminum oxide mineral phases (quartz and mullite), the hardness can reach Mohs level 6-7, the static pressure strength is as high as 70-140MPa, and the true density is 2.10-2.20 g/cm3. comparable to rock. Therefore, cenospheres have high strength. Generally, lightweight porous or hollow materials such as perlite, zeolite, diatomite, pumice, expanded vermiculite, etc. have poor hardness and strength, and thermal insulation products or lightweight refractory products made of them have strength poor disadvantages. Their shortcomings are precisely the advantages of cenospheres, so cenospheres have more competitive advantages and wider uses. Fine particle size and large specific surface area. The particle size of the naturally formed beads is 1-250 microns. The specific surface area is 300-360cm2/g, which is similar to cement. Therefore, cenospheres can be used directly without grinding. The fineness can meet the needs of various products. Other lightweight thermal insulation materials generally have large particle sizes (such as perlite, etc.). If they are ground, the capacity will be greatly increased, and the thermal insulation will be greatly reduced. In this regard, cenospheres have an advantage. Excellent electrical insulation. Cenospheres, after the magnetic beads are selected, are excellent insulating materials and non-conductive. Generally, the resistance of insulators decreases with the increase in temperature, but the resistance of cenospheres increases with the increase in temperature. This advantage is not available with other insulating materials. Therefore, it can make insulating products under high temperature conditions.