The name Cenosphere is made up of two Greek words: Kens (hollow) and Sphaira (sphaira) (sphere). Cenospheres are inert hollow spheres made primarily of silica and alumina that are filled with air or inert gas. Cenospheres are a naturally occurring byproduct of pulverised coal-fired boiler combustion.
They're found floating on the fly ash lagoon's surface. When coal combustion ash is in a molten condition, it forms cenosspheres. The temperature of the molten particles is rapidly quenched by flowing with the combustion gas stream, causing them to ‘freeze in' a spherical shape. Any gas bubbles that form within the molten particles are confined within the spheres as well. Cenospheres are formed by these bubbles, which can appear in many forms within the ‘frozen' particles or as single, concentric forms nearly as large as the diameter of the particles.
The proportion of particles with densities smaller than 2 gm/cm3 in fly ash produced after the burning of Kentucky No. 9 coal may be as high as 87 percent in San Miguel coal fly ash. These results show that if selective extraction could be done properly, cenospheres with a density of less than 2 gm/cm3 may be harvested from ash in its dry form. Cenospheres are one-of-a-kind free-flowing powders made up of hard-shelled, hollow, tiny spheres. Cenospheres have a range of appearances from practically white to grey, and their density is around 0.4–0.8 g/cm3, giving them tremendous buoyancy.
Cenospheres are a versatile filler that can be used in a wide range of commercial and industrial products. Oil well cementing and PVC cushion vinyl flooring are two examples. Fillite, on the other hand, is employed in each scenario because of its specific features, including as strength, low density, and chemical resistance. The key applications areas where Fillite is often utilised are listed below.
Cenospheres are hollow, inert, light-weight spheres constructed primarily of alumina or silica and filled with inert gases or air. They are commonly produced as a by-product of coal combustion in thermal power plants.
Few Indian Major Players
1. Ashtech (India) Pvt. Ltd.
2. Bharathi Rock Products (India) Pvt. Ltd.
3. Minerals & Minerals Ltd.
4. Unirama Industries Ltd.
5. Wolkem India Ltd.