Oily diatomite and galvanic wastes as raw materials for red ceramics fabrication

This work focused on the applicability and viability analysis of oil-contaminated diatomite waste and other two industrial residues (galvanic sludge and glass waste materials) in red ceramic fabrication. Red ceramic samples were produced varying the amount of waste materials. Diatomite content, galvanic sludge, and glass wastes in new materials ranged from 25% to 35%, 20% to 25%, and 5% to 20%, respectively. Natural clay was present by 30%. Mixtures of initial components were hydrated, compacted, dried and baked with different temperatures (950 °C, 1000 °C, 1050 °C, and 1100 °C) during 6 h. The materials were analyzed by Scanning Electronic Microscopy (SEM), Electron Dispersive Spectroscopy (EDS), X-Ray Fluorescence Spectroscopy (XRF) and X-Ray Diffraction (XRD) techniques. Red ceramic samples were subjected to flexion resistance tests. High resistance, low dilatation values, water absorption, solubility and leaching of heavy metals could be observed in the obtained ceramic samples. Those outcomes can be explained by melting of some crystal structures of raw components (completely of Illite and partly of Quartz) and partial transition to amorphous glassy formations, well visible by SEM micrographs. The developed materials can be highly economically attractive because of the utilization of industrial wastes to produce construction materials. The wide-scale use of the method can be environmentally effective.

► The new ceramic structural formation achieving suitable mechanical and chemical properties.
► The rejects of oily diatomite and galvanic sludge waste with heavy metals can be used as raw materials.
► High flexion resistance of new ceramics can be explained by high chemical temperature interaction of initial mixture components.