Ceramic foams manufacturing from slate wastes

Abstract

The objective of the present work is the recovery of slate wastes into a raw material for the ceramic industry. Foams are obtained without any addition of foaming agent thanks to the transformation of component present on the slate during heating. A glass base material with a closed porosity, gray color and density value around to 0,3g/cm 3 has been obtained. Raw material is the slate waste as slurry, after cutting roofing slates. After drying, the slate powders were die pressed to achieve green samples, which were sintered in N 2 -5%H 2 atmosphere at different temperatures, as well as in air as reference material at 1150°C. Dilatometer behavior was studied on die pressed slate powders under both atmospheres as well as X-Ray diffraction in order to determine the crystalline phases on sintered materials. Sintered density decreases as temperature increases under non-oxidant atmosphere, which leads to decrease the mechanical properties with the temperature when the foam structure is developed (over 1075°C on N 2 -5%H 2 atmosphere).