Cenospheres (Expanded Mineral Materials Containing Alumina and Silica) is a by-product of coal-burning power plants and is a lightweight, inert, hollow sphere filled with air or inert gas. the color of the Cenosphere varies from grey to almost white and its density is about 0.4 – 0.8 g/cm3 (0.014 – 0.029 lb./cu in), which provides them with buoyancy. Cenospheres are used as a structural lightweight filler in concrete and plastics. The spheres are mixed with resin to make lightweight syntactic foam used as a core material for sandwich panels, tooling blocks, and buoyancy foam. They are used to make heat-resistant refractory tiles and ceramic coatings with low thermal conductivity. Metal-coated cenospheres are added to EMI shielding paints. Features of Cenospheres(also named Hollow Microspheres): 1. Good fluidity: The hollow microbeads are hollow circular microspheres with a particle diameter of 0.2µm-400µm, and the spherical rate is ≥95%, which increases the fluidity of the filled material and makes the filled material more suitable for processing. 2. Low density: hollow microspheres have a product density of 0. 4g/cm3 -0. 8g/cm3. Compared with most ground mineral materials, hollow microspheres are 30%-85% lighter in weight. 3. High Fill Rate: Hollow microspheres occupy the least surface area to be filled. Due to its spherical structure, the viscosity is greatly reduced. 4. High strength: hollow microspheres can withstand 4000 kg/cm due to their hard shell. Compressive strength from 3 to 7000 kg/cm3. 5. Low Shrinkage: Cavity beads are one of the few materials in the filler field that can achieve low shrinkage. The shrinkage rate of a large number of filled hollow microspheres. 6. Heat insulation and sound insulation: The hollow feature makes the hollow microspheres have low thermal conductivity and can be used for heat insulation and sound insulation materials. 7. Strong stability: hollow microspheres can be added to solvents, organic chemicals, water, acids or bases without changing their chemical properties. 8. High temperature resistance: Since the melting point of hollow microspheres is as high as 1450°C, it can remain stable at high temperatures above 1000°C. 9. Electrical insulation: Use various electrical switches, instrument panels, and electronic packaging materials to improve insulation. 10. Low cost: The price of hollow microspheres is 50%-200% lower than that of artificial microspheres. Lightweight sintered refractory bricks Casting Exothermic Insulation Riser Thermal insulation coating Oilfield cementing