What’s the difference between coal ash, coal combustion “byproducts,” coal combustion “products” and wastes from the combustion of coal?
More than thirty years ago, ash produced from the burning of coal in coal-fueled power plants was simply called “ash.” More than two thousand years ago, the Romans discovered that the naturally occurring volcanic ash, when mixed with other materials could make a very strong, durable mortar or cement. The Coliseum, Roman aqueducts and other structures used this pozzolanic ash in building. In the 1960’s the utility industry realized that coal ash was a valuable product that could be used in many ways in commerce. In 1968 the National Coal Ash Association was formed to help promote the use of coal ash and to provide information about the versatility of the material. As the industry matured, it became obvious that coal ash needed to be categorized by types and uses. Coal ash was classified by the type of coal burned, by the type of boiler in which it was produced, by its physical characteristics and by its end use, among other methods. Fly ash, bottom ash, boiler slag, fluidized bed combus
