Study on the Effect of Binders on the Properties of Mullite Porous Ceramics for Flue Gas Filtration

Abstract

Fused mullite particles are used to prepare mullite porous ceramics by gel-casting method, using polysilicon waste and ρ-Al2O3 powder as the binder, and starch as the pore forming agent. The content of the pore forming agent was 20%, and the ratio of the mass of fused mullite particles to the mass of the binder was 9:1, 8:2, 7:3, and 6:4, respectively. The effects of binder content on the properties of mullite ceramics in terms of phase composition, microstructure, apparent porosity, compressive strength, bulk density, pore size distribution, and filtration pressure drop were investigated. It was found that prepared porous mullite possessed relatively high apparent porosity (56.64-58.19%), and low bulk density (1.28-1.31g/cm3). With increasing binder content, the sintering shrinkage rate increased from 2.07 to 5.92%, the compressive strength increased from 1.01MPa to 6.08MPa. Therefore, the preparation of mullite ceramics was a near net size preparation, and the prepared porous ceramics meet the requirements of flue gas filtration.