Experimental and Computational Study of Thermal Processes in Red Clays Exposed to High Temperatures

Abstract

Fired bricks represent one of the most popular building materials, of which production is still growing. Since the functional properties of bricks have reached their physical limits, the current development aims at an optimization of production procedures as it goes along with heavy environmental loads. This paper is focused on tailoring the firing procedure to optimize the energy demands. Dealing with five different clays, their heat storage properties are determined using inverse analysis of calorimetric data so that the measurement errors are reduced. Moreover, effective values incorporate the thermal processes that occur during firing. A simplified model of clay samples is then used to calculate the energy demands for reaching an optimal firing scheme. The results show that specific treatment is necessary for particular clays as the energy demands may range between 89 and 173 MJ·m−2, depending on a clay composition. The highest demands were found in the case of clays containing the high volume of calcite and dolomite, of which thermal decomposition is very energy demanding. Using the tailored firing scheme, one can reach energy savings of up to 49% while the functional properties would be preserved due to maintaining the optimal temperature evolution in the brick body.

Physical properties of alkali activated aluminosilicates based on low-reactivity ceramics in room temperature conditions

“…The waste ceramic powder, generated in brick plant in Libochovice, Czech Republic, was used as precursor for alkaline activation. Its chemical composition (examined by XRF spectroscopy) is interesting, when compared by "common" red-clay ceramics, by relatively high content of CaO (table 1), what is due to the composition of the loess in Libochovice [12,13]. The phase composition of the precursor (table 2) represents a typical red-clay ceramicsit contains quartz and number of silicate minerals.…”

Investigating the Drying Process of Ceramic Sanitary Ware at Low Temperature

“…The drying and firing processes of ceramic products are characterized by high energy consumption [14][15][16]. Silva et al [5] reported that the energy cost during the drying and firing stages has a considerable influence on the price of the final product, representing about 30% of the total average cost of production.…”

“…In the consulted literature, no studies were found that evaluated the drying process of ceramic materials at low temperatures (less than 50 • C). In addition, such works are limited to simpler geometries, such as hollow bricks and ceramic blocks [1,3,5,7,8,13,16,[19][20][21][22][23][24][25][26][27][28][29][30][31][32][33][34][35]. It was also noticed that the only operational parameter evaluated in the drying process of ceramic materials reported in the literature is the temperature of the drying air; parameters not being evaluated, for example, were cases involving the same temperature and different values for relative humidity and/or velocity, including dimensions variations.…”

“…It was also noticed that the only operational parameter evaluated in the drying process of ceramic materials reported in the literature is the temperature of the drying air; parameters not being evaluated, for example, were cases involving the same temperature and different values for relative humidity and/or velocity, including dimensions variations. When it Energies 2023, 16, 4242 3 of 20 comes to sanitary ware, the works are even more scarce, not even being found experimental drying studies for such products. Therefore, the innovation of the work is evident.…”