The Use Of Wastes As Alternative Fuels In Cement Production

The high burning temperature, the long retention time inside the kiln, the oxidizing atmosphere, the ash absorption in the clinker and the chemical conditions render the cement kilns ideal installations where wastes can be burned safely. Consequently, some of the wastes may be potential candidates to be used as alternative fuels in cement production that boasts a lot of environmental benefits. These wastes include a variety of materials like used tires, animal meal, refusederived fuels (RDF), solvents, used oils and biomass. During the clinker production process, the organic part of the wastes is totally destroyed whereas the inorganic compounds and heavy metals are incorporated in the interstitial phase or substitute calcium or silicon in the silicate phases of the clinker. However, due to their origin these wastes introduce into the cement making process several trace elements that may affect the process itself as well as the properties of the clinker. This work investigates the effects of the use of biomass (cotton stalks) and RDF on the properties of Portland cement clinker. In this respect, ash of these two waste materials was introduced in the raw mix in diverse proportions. The clinkerization characteristics and the microstructure of the lab prepared raw mixes and of the reference mixture were investigated by differential thermal analysisthermogravimetry, optical microscopy and x-ray diffraction. The obtained results suggest that both waste materials, RDF and cotton stalks can be used as alternatives to fossil fuels, such as coal, for the production of Portland cement clinker.