The word Cenosphere is derived from two Greek words ‘Kenos’ which means hollow or void and ‘Sphaera’ which means sphere or round, that literally means ‘hollow spheres’. A Cenosphere is a type of hollow sphere, light weighted and inert that is made of silica and alumina. It is produced as a byproduct of coal combustion at thermal power plants. Cenosphere are light, hard and rigid, waterproof and insulative. It is excellent light-weight filler. This property of light weight makes them useful in a variety of products, especially in fillers. Nowadays, Cenosphere are used in cement as fillers to produce low density concrete. Now, some of the manufactures have started mixing Cenosphere with metals and polymers to make them light weight. In other words, Cenosphere is also known as Hollow Ceramic Microspheres. The density of Cenosphere is about 0.4-0.8 g/cm3 that is, 0.014–0.029 lb/cu in, this property gives them great lightness. Their color varies from gray to almost white.
Cenosphere are occurred naturally as a byproduct of the burning of coal in thermal power plants. The burning process of coal in thermal power plants produces fly ash of coal that contains ceramic particles that is made of Alumina and Silica. The process of coal burning and the fly ash is produced at temperatures of 1,500 to 1,750°C that is (2,730 to 3,180 °F). It is formed through complicated physical and chemical transformation. The chemical composition and structure depends upon the composition of coal that generated them.
Here are some of the uses of Cenosphere:
- In synthetic foams, Cenosphere are used as filler. It gives us a number of benefits such as adding strength to foam, reducing costs, thermal protection etc.
- For years, Cenosphere have been used in oil drilling. It is used to lower the density of a petroleum cement paste.
- It is often used in paints and coating to regulate infra red radiation.
- The properties of Cenosphere such as re-formable, strength etc don’t let the thermosetting and thermoplastics shrink. This is the reason that Cenosphere is being used for years in manufacturing polymers and plastics.
Cenosphere are a kind of spherical, hollow, low density and free flowing micro particles. The Cenosphere are produced as a by-product of the coal combustion at coal power plants. The size of these particles varies from 10 µm to 300 µm. It is strong and light weighted and has the capability to resist high temperature. There is a vacuum inside these Cenosphere particles that gives them a good thermal and insulation property. This is the only reason which makes the Cenosphere an ideal product for insulation as well as automotive applications. The automotive applications of Cenosphere include tyres, clutch facings, brake linings and also friction linings. The process of coal burning is performed at the thermal power plants to produce fly ash that generally contains ceramic substances. If the coal composition and the temperature of the boiler furnace is proper or suitable, then some of the particles of the ash produced undergo a rapid change in physical and chemical transformation to produce Cenosphere, otherwise, the particles of Cenosphere are irregular and random in their shape. As mentioned above, that the Cenosphere are light in weight, and therefore, it is primarily used as filler in oil, gas, plastics, buildings, aerospace, and factories, automotive and also in surface coating industries. Therefore, Cenosphere are described as the multifunctional filler that mixes well in binders and resins like thermosetting and thermoplastics. The advantages of buying Cenosphere from manufacturers are as follows:
- It will surely enhance the flow ability.
- The strength of the Cenosphere is good and is used in Bonding, internal structure such as asphalt, concretes, paints, ceramics.
- It also decreases the cost of raw materials.
- The spherical property of Cenosphere further helps in ball bearing effect for molding and trowel work.
- If the byproduct of coal is used to produce fly ash then the weight of end product also decreases.
Cenosphere have a property of low warm conductivity. They have exceptional mix of low particular gravity, high pressure, and controlled size, great warm and responsible protecting property. They are generally very hard and flexible, waterproof, light and insulative.
Cenospheres are unique free-flowing particles composed of hollow, hard-shelled, minute spheres. A small portion of the PFA (Pulverized fuel ash) formed from the combustion of coal at the thermal power plant is produced as cenosphere India. It is assumed that only about 1 percent of Cenosphere is produced in fly ash from thermal plants due to their hollow and low-density nature and they float in the lagoons where fly ash is discharged. Cenosphere largely consists of Silica, Iron, and alumina. The size of the particles varies ranging from 1 to 500 microns, having an average compressive strength of 3000+ psi. They are alternatively also referred as hollow spheres, microspheres, microballoons, hollow ceramic microspheres, and glass beads. When the hollow spheres float in the lagoons, they are collected and further isolation is carried by froth floatation and then dried. The final application is carried out in a pneumatic conveying system which is connected to a tribo electric separator. In this separator, the ash is divided into three fractions and the cenosphere particles are then separated from iron and carbon. The end product is then used for a variety of applications.
What is fly ash?
As mentioned above, it is considered that only about 1 percent of cenosphere India is produced in the fly ash during the coal combustion in thermal power plant. When coal is burned at a combustion temperature approximately of about 2800oF, the non-combustible ores occurring naturally from coal combustion forms bottom ash and fly ash. According to the cenosphere suppliers in India, bottom ash is a light-weight aggregate component which tumbles to the boiler bottom for collection; whereas, fly ash is carried off with the flue gases. Fly ash particles are then collected and stored in silos for testing and then utilized in different applications for its beneficial chemical and physical properties.
Fly ash material is used widely for its several beneficial characteristics like it increases strength and durability of the application. Further, fly ash particles are less disposed to chemical attacks such as de-icing salts and soil sulfates and thus, alleviate the negative effect of deleterious aggregates.
Cenosphere is inert hollow spheres made largely of silica and alumina and is produced in the process of coal combustion at the thermal power plant. Cenosphere from India is primarily used as a weight-resistant component in a number of applications including plastics, rubbers, cement, and resins. It is also used extensively as filler lubricants for oil drilling operations done under extreme temperature and stressful conditions down the hole. Cenosphere particles are also used as mud putty, oil well cementing, and other such applications.
Initially, cenosphere particles were used in the United States for a variety of applications as an extender for plastic compounds and were compatible with Latex, plastisols thermoplastics, polyesters, phenolic resins, epoxies, and urethanes. Till now, the compatibility of cenospheres with composites and specialty cement and the adhesive coating has been well identified. And in fact, Cenosphere from India are used widely for a variety of products including insulations, sports equipment, automobile bodies, paints, fire and heat protection devices, and marine craft bodies. Classically, it is applied in Gypsum board (fire, moisture, and soundproof solution for improving the quality of indoor air) jointing compounds, stuccos, veneering plasters, sealants, coatings and cast resins. Undoubtedly, it provides huge benefits to the application like reduced weight, better flow characteristics, improved filler loadings, reduced water absorption, reduced shrinkage, and warping.
Characteristics of cenosphere from India:
- Free flowing
- Off-white in color
- Corrosion Resistant
- Fire and flame retardant
- Low density
- Improved Flowability
- Low shrinkage
- Thermal stability
- High compressive strength
Extensive usage of cenosphere from India for different applications:
- Ceramics – Castables, tiles, refractories, fire bricks, tiles, insulating, material coatings, aluminum
- Plastics – injection molding, BMC, SMC, molding, nylon, extruding PVC flooring, film, high-density polyethylene, polypropylene, low-density polyethylene
- Construction – Mortars grouts, specialty cement, roofing material, stuccos, acoustical panels, Shotcrete, coatings, gunite, and so on
- Recreation – Kayaks, Marine craft floatation devices, surfboards, bowling balls, golf equipment, lawn and garden décor, and footwear
- Automotive – Under-coatings, composites, tires, brake pads, engine parts, trim molding, plastics, body fillers, and soundproofing materials
- Energy and technology – Drilling muds, oil well cement, industrial coatings, aerospace coatings and composites, and propeller blades.