Iron- and calcite-rich ceramic bodies for porous tiles manufacturing by fast double-firing

Porous glazed tiles are very important products used for decorative wall coverings. It ¡s possible to obtain porous fast-fired biscuit (35-40 min firing cycle) to produce fast double-fired tiles by using natural ¡ron- and calcite-rich clays, as used in the production of traditional, slow-fired cottoforte (20-30 h firing cycle). Anorthite and diopside are the main crystalline phases developed ¡n fired pressed tiles. A large amount of chlorite and calcite is fundamental to diopside-anorthite formation and to the enhancement of mechanical properties and dimensional stability.