Recycling of foundry sand residuals as aggregates in ceramic formulations for construction materials

The utilization of residual materials in the fabrication of new products has a strong impact on the preservation of non-renewable natural resources, diminishes energetic consumption and avoids the costs and problems that imply the final disposal of them. The aim of this work is to investigate the recycling of waste foundry sand coming from the process of cast iron for use as aggregate in the manufacture of red clay bricks and tiles. The raw materials, waste foundry sand and clay soil were chemically and microstructural characterized and different samples were designed. Compact bodies were prepared with 10%, 20%, 30%, 40% and 50% (wt%) of waste. They were thermally treated in the range 9501000 C. The experimental conditions were established taking into account those used for commercial products. The characterization of raw materials and products was carried out using various techniques. The results allow one to conclude that it is feasible to incorporate important quantities of waste foundry sand into the manufacture process of clay bricks and tiles. The best properties were obtained in samples with 30 and 40 wt% of waste added, taking into account the characteristics required for commercial applications.