Ashconnect Global Trading Pvt. Ltd. - Class A Quality Fly Ash and Products

About Flyash

Fly ash is a fine powder that is a byproduct of burning pulverized coal in electric generation power plants. Fly ash is a pozzolan, a substance containing aluminous and siliceous material that forms cement in the presence of water. When mixed with lime and water, fly ash forms a compound similar to Portland cement. This makes fly ash suitable as a prime material in blended cement, mosaic tiles, and hollow blocks, among other building materials. When used in concrete mixes, fly ash improves the strength and segregation of the concrete and makes it easier to pump.

Fly ash is also known as flue-ash or simply ash.

Where does fly ash come from?

Fly ash is produced by coal-fired electric and steam generating plants. Typically, coal is pulverized and blown with air into the boiler's combustion chamber where it immediately ignites, generating heat and producing a molten mineral residue. Boiler tubes extract heat from the boiler, cooling the flue gas and causing the molten mineral residue to harden and form ash. Coarse ash particles, referred to as bottom ash or slag, fall to the bottom of the combustion chamber, while the lighter fine ash particles, termed fly ash, remain suspended in the flue gas. Prior to exhausting the flue gas, fly ash is removed by particulate emission control devices, such as electrostatic precipitators or filter fabric baghouses.

Applications of Fly Ash

Fly ash can be used as prime material in many cement-based products, such as poured concrete, concrete block, and brick. One of the most common uses of fly ash is in Portland cement concrete pavement or PCC pavement. Road construction projects using PCC can use a great deal of concrete, and substituting fly ash provides significant economic benefits. Fly ash has also been used as embankment and mine fill, and it has increasingly gained acceptance by the Federal Highway Administration.

Fly ash is suitable for a wide variety of applications and uses, including:

Concrete

Dams

Flowable fill

Mines

Landfills

Geopolymer concrete

Physical properties of Fly Ash:

Fineness of Fly Ash

As per ASTM (American Society for Testing and Materials), the fineness of the fly ash is to be checked in both dry and wet sieving. The fineness of fly ash is a measure of percentage retained on 45-micron sieve when a sample is sieved through it. Further fineness is also measured by the LeChatelier method and Blaine Specific Surface method.

Specific Gravity of Fly Ash

The specific gravity of fly ash ranges from a low value of 1.90 for sub-bituminous ash to a high value of 2.96 for iron-rich bituminous ash.

Size and Shape of Fly Ash

As the fly ash is a very fine material, the particle size ranges between 10 to 100 microns. It is usually spherical in shape.

Colour of Fly Ash

The colour of the fly ash depends upon the chemical and mineral components. Light and tan in fly ash are due to the lime content whereas brown colour is present due to the iron content. and dark grey to black colour is due to an un-burned content.

Chemical composition of Fly Ash:

The chemical composition of fly ash depends upon the type of coal used and the methods used for combustion of coal.

Component	Bituminous Coal	Sub-Bituminous Coal	Lignite Coal
SiO₂ (%)	20-60	40-60	15-45
Al₂O₃(%)	5-35	20-30	20-25
Fe₂O₃ (%)	10-40	4-10	4-15
CaO (%)	1-12	5-30	15-40
LOI (%)	0-15	0-3	0-5

Fly Ash