Image of the Day — Fly Ash From a Coal Fired Power Plant

Fly ash is one byproduct of the coal combustion process and represents part of the inorganic material in coal. The amount of fly ash produced varies from 65-85% of the total byproduct, depending on the method of combustion. Fly ash is made up of molten minerals, such as clay, quartz and feldspar that solidify in the moving air stream leaving the combustion chamber. This moving airstream around the molten material helps to give most (>60%) fly ash particles their spherical shape. Electrostatic or mechanical precipitators collect fly ash, which can be up to 97% efficient. Fly ash ranges in size from >0-44μm.