Fly ash is the ash from burning coal that is carried along with the flue gasses. Because fly ash causes air pollution, it is captured. Fly ash composition may differ significantly, depending on the type and mixture of coal and biomass that is being burned.
Fly ash contains substantial amounts of silica - both amorphous and crystalline - and calcium oxide. Both are natural components of carbonaceous rock. The composition of fly ash is important for the production of cement or concrete.
In the Netherlands, fly ash and a limited proportion of biomass is fully reused and processed into cement, concrete, paving setts and asphalt. It compacts the structure of the concrete, protecting it from external influences.
Which analyses are available for fly ash?
- Loss on ignition
- Colour (CIE L*, a*, b*)
- Bitumen value
- Free calcium oxide