Fly Ash | 17 Aug 2020

Why in News

Recently, National Thermal Power Corporation (NTPC) has developed an infrastructure to transport fly ash from power plants in bulk to cement plants, at a cheaper cost.

  • It will pave the way for efficient and environment friendly transportation.
  • This development is in line with NTPC's commitment towards 100% utilization of fly ash from power plants. At present, 63% of the fly ash is being utilised in India.

Key Points

  • Fly Ash:
    • Definition: It is a byproduct from burning of coal in electric power generating plants.
      • It is called fly ash because it is transported from the combustion chamber by exhaust gases.
      • It is collected from the exhaust gases by electrostatic precipitators or bag filters.
    • Composition: Fly ash includes substantial amounts of silicon dioxide (SiO2), aluminium oxide (Al2O3), ferric oxide (Fe2O3) and calcium oxide (CaO).
    • Properties:
      • Resemble Portland cement but is chemically different.
        • Portland cement is a binding material in the form of a finely ground powder, that is manufactured by burning and grinding a mixture of limestone and clay.
        • Its chemical composition includes calcium silicates, calcium aluminate and calcium aluminoferrite.
      • Exhibit cementitious properties.
        • A cementitious material is one that hardens when mixed with water.
    • Uses: It is used in concrete and cement products, road base, metal recovery, and mineral filler among others.
    • Harmful Effects: Fly ash particles are toxic air pollutants. They can trigger heart disease, cancer, respiratory diseases and stroke.
      • When combined with water they cause leaching of heavy metals in ground water.
      • It also pollutes the soil, and affects the root development system of trees.


  • NTPC Ltd. is a central Public Sector Undertaking (PSU) under the Ministry of Power.
  • Aim: To provide reliable power and related solutions in an economical, efficient and environment-friendly manner, driven by innovation and agility.
  • It became a Maharatna company in May 2010.
  • It is located in New Delhi.

Source: PIB