Energy saving in sintering of porcelain stoneware tile manufacturing by using recycled glass and pottery stone as substitute materials

Commercial porcelain stoneware tiles are vitrified tiles (noted as C) that are composed of clay, feldspar, and quartz. They require high temperature sintering at 1230 °C that result in high energy costs. This study aimed to compare the energy consumption during sintering process of the porcelain stoneware tiles, which recycled glass and pottery stone were used in substitution of clay, feldspar, and quartz (noted as N). The sintering temperatures of the commercial (C) and the substituted (N) tiles were, respectively, at 1230 °C and 1050 °C. The physical, mechanical, and chemical properties of the N tiles were compared with those of the C tiles. As a result, the N tiles showed good properties according to several standards, such as water absorption of less than 0.1% (ISO 10545-3), linear shrinkage of less than 10% (ASTM C326), modulus of rupture of more than 40 N/mm2 (ISO 10545-4), and good resistance of chemicals (ISO 10545-13). The N tiles were in compliance with the ISO 13006:2012 (group BIa) Standard. In the sintering process, the energy consumption and CO2 emission of the N tiles were, respectively, 9191.24 kJ/kgProduct and 0.0782 kg CO2eq/kgProduct, while those of the C tiles were, respectively, 13304.84 kJ/kgProduct and 0.1132 kg CO2eq/kgProduct.