Method and apparatus for reducing carbon content in fly ash

Abstract

A method of treating fly ash which has a moisture content and which also has a high carbon particle content includes the steps of heating the fly ash to a temperature sufficient to break the bond between the fly ash and the carbon particles caused by the moisture content, applying the heated fly ash in a relatively thin layer to the surface of a belt-type conveyor and subjecting the layer of heated fly ash to the effects of an electrostatic charging zone while repeatedly mechanically rearranging the orientation of the fly ash particles in the zone for causing the carbon particles to take a charge and become attracted to an electrode so that the same may be separated from the layer. Apparatus for separating carbon particles from fly ash includes a generally horizontal conveyor, and a hopper which applies fly ash to be treated in a layer on the surface of a conductive belt. The belt carries the fly ash layer through an elongated electrostatic charging zone, and beaters beneath the belt impart a vibration to the belt for causing the fly ash layer to be in a state of agitation. The belt forms a lower electrode, while an upper electrode is spaced above the belt and the entire separation zone is environmentally enclosed to exclude ambient air and moisture from the separating zone. Collection bins are positioned along the lateral sides of the belt for capturing carbon particles discharged from the zone, while the accepts are delivered off of the end of the belt into a suitable bin.