Sintered material from alkaline basaltic tuffs

摘要

The possibility to obtain sintered material from alkaline basaltic tuffs is demonstrated. The parent rock was milled for 10-15 min, the resulting powder was pressed at 100 MPa and the obtained samples were heat-treated in the range of 1000-1140 deg C. The sintering behaviour and the phase formation were studied by pycnometry, dilatometry, DTA, XRD and SEM. The final material was obtained by sintering at 1100 deg C and is characterized by zero water absorption, 8-9 vol.percent closed porosity and a structure similar to a glass-ceramic. Due to high crystallization trend of used composition, phase formation takes place during the sintering and cooling steps; this leads to a crystallinity of approx60percent and formation of different crystal phases (pyroxene, anorthite, spinel and hematite). Despite the low-cost production cycle the obtained material is characterized by high mechanical properties: bending strength of 100 MPa and Young modulus of 90 GPa.