What is Fly Ash ?

 Fly Ash :

Ash is produced whenever combustion of solid material takes place. Fly ash is one such residue which rises with the gases into the atmosphere. It is very fine powder and tends to travel far in the air. The ash which does not rise is termed as bottom ash.

⇨Nearly 73% of india's total installed power generation capacity is thermal, of which 90% is coal based generation, with diesel, wind, gas and steam making up the rest.

Composition :

1. Aluminium silicate (in large amount)

2. Silicon dioxide (SiO2)

3. Calcium oxide.

Fly ash particles are oxide rich and consist of silica, alumina, oxides of iron, calcium and magnesium and toxic heavy metals like lead, arsenic, cobalt and copper.

How it is collected ?

⇨Fly ash is generally captured by electrostatic precipitators or other particle filtration equipments before the flue gases reach the chimneys of coal fired power plants.

Environmental effects ?

1. If Fly Ash is not captured and disposed off properly, it can pollute air and water considerably.

2. It causes respiratory problems.

3. Fly Ash in the air slowly settles on leaves and crops in fields in ares near to thermal power plants and lower the plant yield.

Advantages :

1] Cement can be replaced by fly ash upto 35%, thus reducing the cost of construction, making roads etc.

2] Fly Ash bricks are light in weight and offer high strength and durability.   

3] Fly Ash is a better fill material for road embankments and in concrete roads.

4] Fly Ash can be used in reclamation of wastelands.

5] Abandoned mines can be filled up with fly ash.

6] Fly ash can increase the crop yield and it also enhances water holding capacity of the land.