Ceramic material from basaltic tuffs

The possibility to obtain a cheap ceramic material based on 50 wt % basaltic tuffs and 50 wt % industrial clays was studied. The tuffs were characterized by optical microscopy, X-ray diffraction and differential thermal analysis. It was shown that this material is appropriate for the ceramic industry: it is easy for milling and is characterized by low liquidus temperature. The sintering behaviour of the ceramic was evaluated by hot-stage microscopy and dilatometry. The structure of samples, heat-treated at different temperatures, were observed by scanning electron microscopy while the densification degree was evaluated by dry flow and gas pycnometery. Samples with 13% total porosity and 4% water absorption were obtained at 1150 °C for 30 min soaking.