Hazardous industrial wastes as the main components of red ceramics production

Resumo

This research involved the development of new types of red ceramics from class I and II wastes, using different industrial residues such as sludge (WTP sludge, foundry sand, glass residues, residual salts) and clay. The chemical, mineralogical and structural compositions of the residues used as raw material and the new ceramic compounds were analyzed and studied using XRF, XRD, SEM and chemical microanalysis (EDAX). The results obtained indicate that the ceramic prepared with 70% of residues (composition 1), without the addition of sand and with the maximum clay content, presented the highest strength (20 MPa) at 1050°C. Composition 2, with a 5% lower clay content and a 5% higher sand content showed a significantly lower strength at all the temperatures tested. Increasing the proportion of sand to 15 and 20% in compositions 5, 6 and 7 led to a considerable increase in resistance at 1050°C in comparison to the other temperatures. The results showed high flexural strength and low values of water absorption and linear retraction, characterizing the good sintering of the materials and vitreous formation, ensuring low values of solubilization and leaching.