Physical–chemical processes of sustainable materials’ production from hazardous toner waste, galvanic glass waste and spent foundry sand

Several sustainable white ceramic composites were prepared from 3 to 7 wt.% of hazardous toner waste, 30–40% of spent foundry sand, 15–25% of galvanic glass waste, and 35–45% kaolin clay. Developed composites were sintered at 1100°, 1150°, 1200°, 1250°, and 1275 °C. The ceramics’ flexural resistance values reached up to 12.29 MPa, linear shrinkage varied between 2.99 and 11.20%, and water absorption—between 19.90 and 10.85%. The investigation of the ceramics structure formation processes using the X-ray diffraction, X-ray fluorescence, scanning electron microscopy, energy-dispersive spectroscopy, atomic absorption spectroscopy, and lased micro-mass analysis methods showed the synthesis of predominantly glassy structures with the inclusion of mullite and cristobalite crystalline structures. The analysis of the chemical composition of the gases emitted during ceramics firing at 1275 °C by the atomic absorption spectroscopy method, as well as the analyses of solubility and leaching of metals from ceramics sintered, showed that the developed composites and technology were in full compliance with Brazilian sanitary standards.