Innovative Synergistic Valorization of Lignite Fly Ash and Steel Industry Scrap-Soil as Secondary Resources for Compacted Ceramics

Abstract

In the present research, the combined utilization of fly ash (FA), derived from a lignite-fed power station, along with scrap-soil (SS), a steel industry by-product, is investigated, for the development of eco-friendly ceramics, thus enhancing innovation and sustainability. The valorization of these low price and largely available industrial secondary resources as 100% the raw materials mixture in ceramic industry arises interesting technological, environmental and economical benefits. FA and SS were mixed in various proportions (0-70%wt. in SS), cold compacted at 20 tn load using an automated hydraulic press to form a series of 5 cm diameter disc-shaped specimens, and finally sintered at three different peak temperatures (1000oC, 1100oC and 1140oC) for 3h. Then, the specimen microstructure and physico-mechanical properties were characterized. According to the experimental results, a sintering temperature increase from 1000°C up to 1140oC significantly improves specimen densification, thus sharply enhancing the diametral tensile strength (DTS), from 0.5 MPa up to 12.8 MPa respectively for a 50-50%wt. FA-SS mixture. Mechanical strength also varies with the SS percentage in the raw materials. Physico-mechanical properties seem to be constant for specimens containing SS up to 60% at 1140oC.