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 hot-stage 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 degrees C 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 degrees C. The investigation has showed that, due to the high porosity and low crystallinity, alkaline tuffs could be a suitable raw material for ceramic application. (C) 2009 Published by Elsevier Ltd and Techna Group S.r.l.