Fly Ash

Fly ash is a fine powder which is a by-product of burning pulverized coal in electric generation power plants. Fly ash is a Pozzolans, a substance containing aluminous and siliceous material that forms cement in the presence of water. When mixed with lime and water it forms a compound similar to Portland cement. The fly ash produced by coal-fired power plants provides an excellent prime material which can be used for different applications

Applications

  • Portland Cement
  • Mosaic Tiles
  • Hollow Blocks
  • Paving Bricks
  • Mine Fills

Types of Fly Ash

  • According to the type of coal used fly is classified into two types. Anthracite and bituminous coal produces Fly Ash classified as class F. Class C Fly Ash is produced by burning lignite or sub-bituminous coal. Class C Fly Ash has self-cementing properties.
  • Class F and Class C Fly Ash are products of the combustion of coal in large power plants. Fly Ash is collected in electrostatic precipitators or baghouses, and then transferred to large silos for shipment. When needed, Fly Ash is classified by precise particle size requirements, thus assuring a uniform, quality product.
  • Class F Fly Ash is available in the largest quantities. Class F is generally low in lime, usually under 15 percent, and contains a greater combination of silica, alumina and iron (greater than 70 percent) than Class C Fly Ash.
  • Class C Fly Ash normally comes from coals which may produce an ash with higher lime content — generally more than 15 percent often as high as 30 percent. Elevated CaO may give Class C unique self-hardening characteristics.

Test Results

Test Name Test Results Requirements as per ASTMC618
SiO2 + Al2O3 + Fe2O3 % 88.59 70 Min.
Silica as SiO2 % 55.93 N.S.
Alumina as Al2O3 % 25.65 N.S.
Iron as Fe2O3% 7.01 N.S.
Titanium as TiO2% 1.13 N.S.
Calcium as CaO % 4.15 N.S.
Magnesium as MgO % 1.79 N.S.
Sodium as Na2O % 1.81 N.S.
Potassium as K2O % 1.09 N.S.
Sulphates as SO3% 0.20 5 Max.
Retention on 45 Micron Sieve % 13.96 34 Max.
Phosphorus as P2O5 % 0.35 N.S.
Chloride as Cl % Less than 0.10 N.S.
Moisture as MOI % 0.22 N.S.
Loss on Ignition % 0.21 6 Max.