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A cenosphere is a lightweight, inert, hollow sphere made largely of silica and alumina and filled with air or inert gas, typically produced as a byproduct of coal combustion 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. Cf. glass microspheres.

Cenospheres are hard and rigid, light, waterproof, innoxious[citation needed], and insulative. This makes them highly useful in a variety of products, notably fillers. Cenospheres are now used as fillers in cement to produce low-density concrete[citation needed]. Recently, some manufacturers have begun filling metals and polymers with cenospheres to make lightweight composite materials with higher strength than other types of foam materials[citation needed]. Such composite materials are called syntactic foam. Aluminum-based syntactic foams are finding applications in the automotive sector.[citation needed]

Silver-coated cenospheres are used in conductive coatings, tiles and fabrics. Another use is in conductive paints for antistatic coatings and electromagnetic shielding.[1]


The word cenosphere is derived from two Greek words kenos (hollow, void) and sphaera (sphere), literally meaning "hollow spheres".


The process of burning coal in thermal power plants produces fly ash containing ceramic particles made largely of alumina and silica. They are produced at temperatures of 1,500 to 1,750 °C (2,730 to 3,180 °F) through complicated chemical and physical transformation. Their chemical composition and structure varies considerably depending on the composition of coal that generated them.

The ceramic particles in fly ash have three types of structures. The first type of particles are solid and are called precipitator. The second type of particles are hollow and are called cenospheres. The third type of particles are called plerospheres, which are hollow particles of large diameter filled with smaller size precipitator and cenospheres.

Fuel or oil cenospheres[edit]

The definition of cenosphere has changed over the last 30 years. Up until the 1990s it was limited to a largely carbonaceous sphere caused by the oxygen-deficient combustion of a liquid fuel droplet that was cooled below 200 °C (392 °F) before it was consumed. These fuel cenospheres indicated a combustion source using injected droplets of fuel or the open burning of heavy liquid fuels such as asphalt or a thermoplastic material that were bubbling as they burned; the bursting of the bubbles created airborne droplets of fuel.[2][3] This is still a common definition used in environmental microscopy to differentiate between the inefficient combustion of liquid fuels and the high temperature fly ash resulting from the efficient combustion of fuels with inorganic contaminants. Fuel cenospheres are always black.[4]

The refractory cenosphere as defined above is synonymous with microballoons or glass microspheres and excludes the traditional fuel cenospheres definition.[5] The use of the term cenosphere in place of microballoons is widespread, and it has become an additional definition.

See also[edit]


  1. ^ "About our Products: Silver Coated Cenospheres". Camouflage.com.au. Retrieved 29 May 2013. 
  2. ^ McCrone, Walter C.; Draftz, Ronald G.; Delly, John Gustav (1967). The Particle Atlas. Ann Arbor Science Publishers. p. 349. 
  3. ^ Hopke, Philip K. (1985). Receptor Modeling in Environmental Chemistry. Wiley-Interscience. pp. 43–44. 
  4. ^ "Cenospheres from Diesel Fuel". Microlabgallery.com. Retrieved 29 May 2013. 
  5. ^ Brady, George S.; Clauser, Henry R., eds. (1979). Materials Handbook (Eleventh ed.). McGraw-Hill. p. 490. 

Original courtesy of Wikipedia: http://en.wikipedia.org/wiki/Cenosphere — Please support Wikipedia.
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28 news items

Digital Journal
Mon, 23 Nov 2015 14:07:30 -0800

The report provides a basic overview of Cenosphere industry including definitions, applications and industry chain structure. Global market analysis and Chinese domestic market analysis are provided with a focus on history, developments, trends and ...
PR Newswire (press release)
Fri, 23 Jan 2015 15:00:38 -0800

The Global Cenosphere Industry Report 2015 is a professional and in-depth study on the current state of the cenosphere industry. The report provides a basic overview of the industry including definitions, classifications, applications and industry ...
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Global Oilfield Cenosphere Industry> was a professional and depth research report on Global Oilfield Cenosphere industry that you would know the world's major regional market conditions of Oilfield Cenosphere industry, the main region including North ...


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Science 2.0
Tue, 12 May 2015 15:01:06 -0700

A new metal matrix composite that is so light that it can float on water, so a boat made of it would not sink despite damage to its structure - and this syntactic foam has good heat resistance too. Syntactic foams have been around for many years but ...


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Business Standard
Thu, 30 Apr 2015 09:30:00 -0700

This industrial waste is mainly used for land and mine void filling, ash pond dyke raising and other such purposes like cenosphere, soil remediation and levelling of common spaces. The cumulative fly ash accumulation in ash ponds and mounds is pegged ...

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The asteroid that wiped out the dinosaurs set off an intense heat wave that briefly boiled the Earth's atmosphere – but it didn't burn off all the plants. Humanity has not been unlucky enough to observe at first hand the effects of a large impact, so ...

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