Incorporation of fine steel sludge waste into red ceramic

This work has as its objective to evaluate the effect of incorporation of fine steel sludge waste on the properties and microstructure of a kaolinitic clay used to fabricate bricks and roofing tiles. Characterization tests of the steel sludge employed X-ray diffraction, chemical composition, particle size distribution, scanning electron microscopy and DTA/TG analysis. Compositions were prepared with additions of 0, 5, 10 and 20 wt.% waste in a kaolinitic clay from Brazil. To determine the technological properties such as bulk density, linear shrinkage, water absorption and flexural strength, press molded specimens were fired in laboratory furnace at 900 °C. The microstructure of the fired specimens was evaluated by SEM and XRD. The results showed that incorporations up to 5 wt.% of fine steel sludge is beneficial to the red ceramic. By contrast, incorporations above 5 wt.% cause deleterious effect on the mechanical strength of the fired specimens.