Influence of zeolites on the sintering and technological properties of porcelain stoneware tiles

• Published in: Journal of the European Ceramic Society 2003, Vol.23 (13), p.2237-2245
• Main Authors: de’ Gennaro, Roberto, Cappelletti, Piergiulio, Cerri, Guido, de’ Gennaro, Maurizio, Dondi, Michele, Guarini, Guia, Langella, Alessio, Naimo, Debora
• Format: Article
• Language: English
• Subjects: Applied sciences; Building materials. Ceramics. Glasses; Ceramic industries; Ceramic tiles; Chemical industry and chemicals; Exact sciences and technology; Heavyclay products, whiteware; Porcelain stoneware; Sintering; Tiles; Traditional ceramics; Zeolites
• ISSN: 0955-2219; 1873-619X
• DOI: 10.1016/S0955-2219(03)00086-4

Low-cost zeolitic rocks are promising substitutes for feldspathic fluxes in ceramic bodies, since their fusibility, modest hardness and high cation exchange capacity (CEC) should improve grinding and sintering. Five large-scale Italian deposits of natural zeolites with different mineralogy were characterised and tested in porcelain stoneware bodies. Their behaviour during processing was appraised and compared with that of zeolite-free bodies. Zeolites increased the slip viscosity during wet grinding, causing a coarser grain size distribution and consequently some drawbacks in both unfired and fired tiles. After overcoming this hindrance by dry grinding of zeolite rocks, the technological behaviour of zeolite-bearing tiles appear to be similar to that of current porcelain stoneware, though with larger firing shrinkage and residual closed porosity.