Method and system for reprocessing high carbon coal fly ash to produce cementitious materials

Abstract

A method is provided of thermally processing carbonaceous ash and ancillary carbonaceous material to produce a carbon-free inert, pozzolanic, or cementitious material and synthesis gas. The carbonaceous ash and ancillary fuels are fed into a thermal reactor along with oxides provided in the ash or in additives including limestone or glass. Carbon in the ancillary fuel and coal fly ash is converted to synthesis gas that is combusted to generate process steam and electricity. Remaining ash exits the thermal reactor chamber for processing at high temperature in a kiln gasifier to react the remaining fixed carbon and produce carbon-free partially-fused nodules or clinker that are cooled and ground to a desired fineness for cementitious or aggregate material in concrete. Carbonaceous ash, especially high carbon coal fly ash and other carbonaceous waste, are converted to energy and non-toxic, carbon-free aggregate or cementitious material used as architectural fill or in concrete mixes.