Effect of the incorporation of a spent catalyst reject from the petroleum industry in clay products

Clay-based materials show a natural forgiveness towards the incorporation of a variety of materials, including potentially hazardous industrial rejects or sub-products. Research from the past few years suggests that the red clay ceramics industry might become the natural end-user of waste materials from other industries. In Brazil, the growth of the petroleum industry is leading to an increasing amount of wastes with high environmental impact and the industry is looking for alternatives to the simple disposal of the wastes. The study reported here shows the changes in properties of an industrial red clay-based mixture, already in use in the production of bricks, due to additions of a spent catalyst reject material (SCR) discarded by the thermal cracking process in the petroleum industry. Samples containing 20 wt.% SCR were extruded and sintered in air in an electric furnace (700-1150 degrees C, for 1 h). The results obtained (X-ray diffraction and fluorescence, thermal analysis, firing shrinkage, water absorption and mechanical strength) show the effect of the SCR additions and suggest that the incorporation of the SCR material into the clay mixture can constitute a valid route to the amelioration of the environmental concerns. (C) 2008 Elsevier B.V. All rights reserved.