Description of Cenosphere

Cenospheres are light weight, inert, hollow speres of Silica and Alumina filled with gas which naturally occurs in the combustion of coal. The properties are same as manufactured sphered products. Thus it is also called as Glass beads. Hollow Ceramic Sphere or Microspheres.

Due to their unique combination of low specific gravity, spherical shape, controlled size, high compression , good thermal and acoustical insulation property, many high value applications can be made.

Cenospheres are chemically inert and exempt from classication as a "Hazardous Waster" by the U.S.Environmental Protection Agency. They are also considered reclaimable and labelled as "Environmental Sound".

Properties of Cenosphere

The word Cenosphere is derived from two Greek words Kens (hollow) and Sphaira (sphere).

Cenospheres are hollow ceramic microspheres found in fly ash, a natural by-product of coal combustion during the generation of electric power. Small and hollow, microspheres are used as fillers or functional extenders in the manufacture of plastics, paints, resins; light weight aggregates for cement, ceramics and other construction products. Because Cenospheres often replace mined materials, they can significantly lower production costs. Simultaneously, cenosphere can benefit finished product properties by increasing durability and better sound proofing. Too, as material recycled from fly ash, cenosphere are environmentally friendly and help to preserve natural virgin fillers.

As a portion of the fly ash generated in coal combustion, cenosphere are recycled from the waste stream. They are made up of inert silica, iron and alumina. Cenospheres have a size range from 1 to 300 microns with an average compressive strength of 3000+ psi.. Colors range from white to dark gray. They are also referred to as microspheres, hollow spheres, hollow ceramic microspheres, micro balloons, or glass beads.

The spherical shape of cenosphere improves flow ability in most applications and provides a more even distribution of the filler material. The natural properties of cenosphere make it possible to use them either in dry or wet slurry form. Cenospheres are easy to handle and provide a low surface area-to-volume ratio. Due to their inert properties, they are not affected by solvents, water, acids, or alkalis. Cenospheres are 75% lighter than other minerals currently used as a filler or extender.

The mainly advantages of using cenosphere are :

  • Reduced Raw Materials Cost
  • Improved Flow ability
  • Reduced Resin Demand
  • Improved Insulation Values
  • Reduced End Product Weight
  • Resistant to Resin Absorption


Safety data sheet of Cenospheres

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