Fly ash is a by-product of which process?

Fly ash is a fine particulate material that becomes airborne during the combustion of pulverized coal in electric power plants. When coal is burned, it produces these tiny particles, which are carried up the flue gas. As the flue gases cool, the particles are removed from the gas stream by various methods, such as electrostatic precipitators or bag filters, and then collected as fly ash.

This by-product is often utilized in various construction applications, particularly as a supplementary cementitious material in concrete, enhancing strength and reducing the environmental impact of concrete production. Understanding the origin of fly ash is essential since its properties significantly affect its utility in construction and its behavior in different applications.

The other processes listed do not produce fly ash; for instance, the combustion of natural gas primarily results in less particulate matter since it burns cleaner compared to coal. Similarly, incineration of plastic waste and burning of biomass materials primarily produce different types of ash and by-products, not fly ash specifically associated with coal combustion.