A cenosphere or kenosphere is a lightweight, inert, hollow sphere made largely of silica and alumina[1] and filled with air or inert gas, typically produced as a coal combustion byproduct at thermal power plants. The color of cenospheres varies from gray to almost white and their density is about 0.4–0.8 g/cm3 (0.014–0.029 lb/cu in), which gives them a great buoyancy.
Cenospheres are hard and rigid, light, waterproof and insulative. This makes them highly useful in a variety of products, notably fillers.
- ^ Kim, H.S.; Islam, M. (2009). "Syntactic foams as building materials consisting of inorganic hollow microspheres and starch binder". In Cornejo, Donald N.; Haro, Jason L. (eds.). Building Materials: Properties and Performance and Applications. Hauppauge, NY: Nova Science Publishers. pp. 1–56. ISBN 9781607410829.