Porous ceramics based on synthetic wollastonite

Marble powder generated as dust by the marble cutting industries and silica fume generated as a by-product in the production of silicon and ferrosilicon alloys were used as abundantly available sources for the preparation of porous wollastonite ceramics. Samples containing up to 20 mass-% graphite were sintered at temperatures between 1100 and 1200 °C. s-wollastonite was detected as a single phase at 1100 °C and a mixture of s- and α-wollastonite was identified at highertemperatures. The samples displayed an apparent porosity of 52-60% and compressive strength of 16-42 MPa, depending on the sintering temperature and graphite content.