Removal of toxic metals from industrial sludge by fixing in brick structure

The aim of this study was to test utilization possibilities of industrial sludge in masonry industry, as well as risk of toxic elements leaching potential. Sludge is generated in a hot-dip galvanizing process after waste water neutralization. This waste is considered to be hazardous due to the presence of toxic elements, which can be fixed within heavy clay matrix after thermal treatment. Relatively large amounts of toxic metals were found in used raw materials, but their leachability reduces to a negligible level after firing at 1020 °C. The results show that sludge can be used to produce eco-friendly bricks.