Characterization of basaltic tuffs and their applications for the production of ceramic and glass-ceramic materials

Alkaline basaltic tuffs, from Southern Turkey were characterized and employed to obtain ceramic and glass–ceramic materials by combined sintering and crystallization process. The chemical and mineralogical compositions were analyzed by X-ray fluorescence spectrometry and X-ray diffraction analyses, respectively. The phase formation and the sintering behaviour were investigated by DTA, differential dilatometer and hotstage microscopy. The micro-structure and residual porosity of the sintered samples were observed by SEM and evaluated by pycnometric techniques. Ceramic material, based on 50% basaltic tuff and 50% clay, was obtained at 1150 8C with 13% total porosity and 4% water absorption. Glass–ceramic materials were synthesized directly using the milled basaltic tuff by mean of the sinter-crystallization technique, in the range 900– 1150 8C. The investigation has showed that, due to the high porosity and low crystallinity, alkaline tuffs could be a suitable raw material for ceramic application.