Ceramic wastes as alternative raw materials for Portland cement clinker production

The cement industry has for some time been seeking procedures that would effectively reduce the high energy and environmental costs of cement manufacture. One such procedure is the use of alternative materials as partial replacements for fuel, raw materials or even clinker. The present study explores the reactivity and burnability of cement raw mixes containing fired red or white ceramic wall tile wastes and combinations of the two as alternative raw materials. The results showed that the new raw mixes containing this kind of waste to be technically viable, and to have higher reactivity and burnability than a conventional mix, providing that the particle size of the waste used is lower than 90 μm. The mineralogical composition and distribution in the experimental clinker prepared were comparable to the properties of the clinker manufactured with conventional raw materials. Due to the presence of oxides such as ZnO, ZrO2 and B2O3 in tile glazing, the content of these oxides was higher in clinker made with such waste. The mix of red and white ceramic wall tile waste was found to perform equally or better than each type of waste separately, a promising indication that separation of the two would be unnecessary for the purpose described above.This study was funded by the Spanish Ministry of Education and Science (MEC) under grants for Projects CTM2004-06619-CO2-01 and 02/TECHNO. I. Garcı´a Dı´az and M. Palacios benefited from pre-Ph.D. grants awarded by the MEC and the Region of Madrid (CAM), respectively, and S. Martı´nez-Ramı´rez from a “Ramón y Cajal” contract funded by the MEC and the ERDF.Peer reviewe