Preparation and Water Permeation Property of Bimodal Porous Cordierite Ceramics

Abstract

Porous cordierite ceramics were prepared from the flyash exhaust of a power plant. Addition of the coal powder to the cordierite green bodies was effective for increasing the open pore volume. The size and the shape of pores were approximately the same as those of the original coal powder particles, and pore size could be controlled in the range from 50 to 1000μm by controlling the particle size of the coal powder. While, the intrinsic pore size of cordierite ceramics without coal additives was about 10μm. Thus, the porous ceramics showed bimodal pore size distributions. The observed correlation between the content of coal particle and the open pore volume percent well agreed with the calculation based on the density of the dried body and the coal. Pure water flux through the disc sample without coal powder addition was 2.08×10-5m3/m2⋅s, but it increased 40 times when the volume percent of the large pores in the body became 45%. The increase in the pure water flux was well explained by a model in which pure water passes preferentially through the larger pores.