The use of a calcium carbonate residue from the stone industry in manufacturing of ceramic tile bodies

The substitution of clayey raw materials for other wastes, in this case sludge rich in calcium carbonate, in the production of traditional ceramics could give rise into cost savings due to the utilisation and recycling of wastes as a secondary raw material. At the same time, it can be helpful for solving environmental problems associated with such wastes. This research shows the results of the addition to a clay of a calcium carbonate residue in different proportions (15, 20, 25, 30 and 35%) in a ceramic body. The most suitable products were selected regarding the mineralogical composition of the resulting ceramic material and its technological behavior. In order to evaluate the ceramic properties of the obtained material, several properties of processing and product (linear contraction, water absorption capacity, bending strength) have been determined. With regard to the technological properties of the final ceramic bodies, there seems not to be any clear relation between the values of linear contraction and the percentage of residue. However, the increase in water absorption with the increase in the residue percentage is evident. The addition of residue gives rise to a decrease in the bending strength. The selection of the adequate percentage of sludge to be added to the ceramic body will be controlled by the usual standards applied to specific construction materials. (C) 2008 Elsevier BY. All rights reserved.