Evolved gas analysis of clay materials

Abstract

Ceramic materials were produced at different temperatures, and the gases released during firing were analyzed using a commercial system based on photothermal techniques. Emissions of CO, CO2, NO, N2O, and CH4 were observed, while NH3 and SO2 were not observed within our detection limits (1 ppm). The evolution of crystalline phases, open porosity, volumetric shrinkage, and rupture tension were correlated to the amount of gases released at different temperatures, ranging from 300 to 1200 °C, and these results can be applied to an optimization of the production process.

Análise dos gases poluentes liberados durante a queima de cerâmica vermelha incorporada com lodo de estação de tratamento de água

“…De fato, os lodos de estação de tratamento de águas são, geralmente, ricos em matéria orgânica [10]. É importante destacar que o vapor de água resultante da desidratação de hidróxidos e, principalmente, da desidroxilação da caulinita tende a aumentar a atividade dos componentes gasosos [18,19]. Observa-se, ainda que em torno de 700 ºC a emissão de CO 2 é maior para as amostras contendo lodo de ETA.…”

Effect of heating rate on gas emissions and properties of fired clay bricks and fired clay bricks incorporated with cigarette butts

“…In bricks, the pore system is important because it affects the gas emissions that occur during dehydration, oxidation, dehydroxylation, decomposition and the formation of new phases and vitrification that generally improve the product's mechanical strength, durability and other properties. A slow heating rate is preferable to prevent the texture from being disrupted by the evolution of water vapour (Murad and Wagner, 1998;Parsons et al, 1997;Santos et al, 2003;Toledo et al, 2004). However, it leads to higher gas emissions.…”

“…The results are presented in ) could be due to the high concentration of water vapour which was maintained within the pore system and thus inhibited the organic content oxidation. Moreover, according to Santos et al (2003) and Toledo et al (2004), CO 2 emissions are due to the oxidation of organic content, while CO evolution is due to incomplete oxidation of organic content. This condition explains the significantly decreasing values of these gases at fast heating rates.…”

“…Attempts have been made to investigate the volumes of gases released at different temperatures and their correlations with the clay properties; see for example the studies by Parsons et al (1997), Santos et al (2003) and Toledo et al (2004). In particular, Dunham et al (2001) and Rasmussen et al (2012) investigated shorter firing times in the manufacturing of clay bricks while Dondi et al (1999) compared the influences of fast firing and traditional firing on physical and mechanical properties of clay bricks.…”