Patent ID: 6691628
Filing Date: 2004-02-17
Classification: F23G,F23J

Abstract:
A method for thermal processing of powder raw materials in a manufacture of cement clinker from raw meal, in which raw materials are preheated as the raw materials move in a material flow direction in at least one heat exchange line comprising a cyclone heat exchange system through which waste gas of a rotary kiln flows in a gas flow direction, the raw materials are calcined in a pre-calcination stage, and fired in a sintering zone of a rotary kiln into cement clinker, which is cooled in a downstream cooler, the rotary kiln waste gas flow supplied with fuel in the pre-calcination stage being used for the pre-calcination of the raw meal, comprising the further steps of directing an entire waste gas flow from the heat exchange line through an oxidation zone downstream of the heat exchange line in the gas flow direction, the oxidation zone having an excess of oxygen and open flames provided by an afterburner, in order to assure burnout or oxidation of pollutant substances CO, S2âˆ’, VOC (volatile organic carbon) such as hydrocarbons caused by a respectively high level of TOC (total organic carbon) and/or sulfides in the raw materials, which otherwise result in high emissions of pollutants.