Avaliação dos efeitos da presença de metais pesados nos resíduos co-processados quando utilizados como combustíveis alternativos e matéria-prima na indústria cimenteira

Abstract

This work presents a overview about the use of waste as alternative fuels in rotary kilns of cement industry concerning to the types of fuels and its characteristics. The cement industry has been using the technology of co-processing of residues as one in the ways of to decrease its production costs and to assist the conservation politics of energy. Besides, this technology provides to the generating industries of hazardous waste to solve their problems of final disposition of this wastes, assisting to the effective environmental legislation. The technology of co-processing of residues in clinker kilns does not restrict only the thermal destruction of the residues, therefore in these kilns, the fuel and the raw materials are founded in the process, turn very important to determine the characteristics of the fuel and its components to have control on the flame characteristics, heat capacity of the fuel and also about the incorporation of ashes to the clinker. To this control it is necessary to analyze the chemical composition of the alternative fuels, as well as the presence of minor components, including heavy metals. The substitution percentage of this alternative fuels in process have also to be analyzed. Thus, will can be controlled and maintained the limits of pollutants emissions in agreement with the effective environmental legislation, avoiding or decreasing operational problems, such as the formation of collages, deterioration of the refractory revetment and unstable operation of the kiln, and also, to evaluate the effects of the presence of such constituent in the quality of the clinker and of the resulting cement. The objective of this work will be to relate the types of residues current used in co-processing, its components and some of the main effects caused by its use in the thermal process of clinker production.