Novel mullite-based ceramics manufactured from inorganic wastes

Statistical design for recycling kaolin processing waste in the manufacturing of mullite-based ceramics

“…The bodies presented mullite (3Al 2 O 3 .2SiO 2 ), quartz (SiO 2 ) and/or alumina (Al 2 O 3 ) as crystalline phases after firing at 1300 °C and 1400 °C. The XRD patterns show that mullite and alumina are the main crystalline phases presented in compositions M 12 , M 13 and M 14 after firing at 1400 °C.…”

“…Table 5 shows the results obtained, indicating that the errors of the predicted values are low, thus confirming the validation of the calculated models. Figure 3 depicts the X ray diffraction patterns of the test specimens of the compositions M 11 , M 12 , M 13 and M 14 after firing at 1300 and 1400 °C. The bodies presented mullite (3Al 2 O 3 .2SiO 2 ), quartz (SiO 2 ) and/or alumina (Al 2 O 3 ) as crystalline phases after firing at 1300 °C and 1400 °C.…”

“…Thus, there is a need to find solutions enabling kaolin processing waste to be incorporated into products of higher added value. In this respect, incorporation of wastes in mullite-based ceramics is being sought and is of high commercial interest [10][11][12][13] . Mullite (3Al 2 O 3 .2SiO 2 ), is the only stable compound of the SiO 2 -Al 2 O 3 binary system under atmospheric pressure, is widely used in conventional and advanced ceramics because of its high melting point, low coefficient of thermal expansion, excellent creep resistance, good chemical stability and high strength at high temperature 11,13,14 .…”

Eco-friendly processing and methods for ceramic materials - A review

“…Works have been carried out on the feasibility of reusing by recycling and recovering energy by incineration from the domiciliary and industrial wastes such as glasses and glassceramics 22) and high-mullite refractory bodies. 23), 24) Ceramic green bodies must be treated at high temperatures to facilitate bonding among the individual powders and to induce enough strength required during service. Low temperature sintering is a great asset particularly in controlling the microstructure evolution because physical properties are directly related to density and microstructure, and further in lowering the operational costs.…”

“…Barbieri et al 79) reported the possibility of recovering the steel ash both as a starting material in glass and glass-ceramic formulations and as coloring agent in place of a pure iron oxide into a colorless base system. Costa Oliveira et al 23), 24) proposed economically feasible recycling of both slate sludge and aluminum-containing residues to produce high-mullite refractory bodies. Although the optimum sintering window was found to be narrow (± 25°C) within the range of 1425-1450°C and large shrinkage rate (up to 30%), recycling of such wastes was suggested as an environmentally friendly recycling method as well as low-cost ceramic products to be used in the construction or foundry sectors.…”