fly ash

…finely divided particulate material called fly ash, are carried along in the incinerator airstream. Fly ash includes cinders, dust, and soot. In order to remove fly ash and gaseous by-products before they are exhausted into the atmosphere, modern incinerators must be equipped with extensive emission control devices. Such devices include…

…later became available, such as fly ash from power stations, sometimes with a cement admixture; bentonite; bituminous materials; sheet polythene; or concrete.