The appellation Cenosphere is derived from the Greek word 'Kenos' and 'Sphaira' which means 'hollow sphere'. Thus, Cenospheres are the balls of aluminium silicate between the range of 10 to 600 micrometres. They are the by-product of stone coal exposed to combustion at a certain temperature. The density of Cenosphere is about 0.4 – 0.8 g/cm3 (0.014 – 0.029 lb/cu in) and its colour varies from white to grey depending upon the type of coal that has been chosen for the combustion process. They are also known as Glass-beads or Expanded Mineral Materials Containing Alumina and Silica due to their similar appearance with the material of glass.
How Cenospheres are obtained?
There are many methods through which Cenospheres are obtained. One of the common methods to separate cenospheres from lignite fly ash is through the 'Sink Float Method'. Through this method, the ceramic particles that contain alumina and silica are separated from fly ash that came out from thermal power plants in the process of burning coal. Cenospheres are produced at temperatures of 1,500 to 1,750 °C (2,730 to 3,180 °F) through various chemical and physical transformations. National Geographic channel in one of its research states that the fly ash and other residuals of coal estimate 136 million tons and 100 million tons in the United States and Europe respectively. Thus, if we can utilize such waste into something meaningful and productive we can save the resources and environment effectively.
What are the substantial qualities of Cenospheres?
Cenospheres can increase the thermal insulation of the product. They are fire-resistant, used as an additive in drilling mud in the wells, and augment the lifespan of drilling equipment. They have low density (0.60 - 0.70 g/cc) and high compressing strength (2000 - 4800 psi). They are insulative, innoxious, waterproof, hard, and rigid substances. They improve workability, reduce shrinkage, and enhance the isotropic properties of the substance. Cenospheres can resist heat up to 1500 degrees Celsius thus they have excellent heat resistant capacity and exhibit great magnetic interactions. Though the thickness of the Cenosphere depends upon chosen coal and its combustion process, the ideal thickness of the Cenosphere shell ranges from 1 to 160 µm
Why Cenospheres are a highly demanded substance today?
Recently, there is a massive demand for Cenospheres due to their polymeric composites which are useful in the oil and gas industry, biomedical, industrial construction, automotive, and refractory industry purposes. Though Cenospheres are obtained from chemical composition yet they are ecologically friendly substances. Cenospheres can be used for coating diesel engines, for manufacturing railway sleepers, composite beams, and decorative items. In Oil and Gas Industry Cenosphere is used in the production of lightweight grouting mixtures, liquids for damping of oil, acid-grouting compounds, and condensate gas wells. In the Biomedical field, Cenospheres are used to control medicines dosage, improve therapeutic effects, used to targeted drug delivery in the stomach, and helps to increase retention capacity in the gastrointestinal tract. In one of its surveys conducted by the French Industry Journal, they highlighted the characteristics of Cenosphere as “The price of Cenospheres is difficult to assess, the market is certainly growing. One good indicator, [is that] the price of a ton has doubled in the past two years.”
Who all are the greatest producers of Cenospheres in the world?
The greatest producers of Cenospheres are Russia, China, U.S., and India. It is estimated that around 1 billion Cenospheres are produced worldwide every year from 50,000 thermal power plants. In India, PETRA BUILDCARE PRODUCTS is the largest manufacturer of Cenospheres. PETRA ‘FILLIT’ has mass production of Cenospheres which contain high quantity of iron (1% - 5%), alumina (25% - 35%) and silica (55% - 65%). The size of Cenospheres manufactured by PETRA BUILDCARE varies from 1 to 500 microns with an average of 3000+ psi compressive strength.
What are the benefits of Cenospheres?
As Cenospheres are used in syntactic foams, they are often used as fillers in specialized solids. They add strength to the product, reduce the cost, and provides thermal protection to the substance. They can resist hydrostatic pressure for a longer duration and are considered an ideal product for ocean engineering. Cenospheres are very light, have a high melting point and compression strength, it has a low coefficient of heat conduction thus considered as best for multiple performances. Presently, Cenosphere is a highly demanded ceramic sphere in the industrial and petroleum sectors.