Preparation and properties of high-purity porous alumina support at low sintering temperature

Abstract High-purity porous alumina supports have been prepared at low sintering temperatures from alumina powders (99.99%, d 50 =10 μm) coated by boehmite sol via electrostatic adsorption. The effects of sintering temperature and relative weight ratio of boehmite on microstructure, bending strength, porosity and pore size distribution were investigated. With sintering temperature increasing, open porosity and average pore size decrease and bending strength increases. Although open porosity and mechanical strength aren’t dependent on the weight ratio of boehmite, the adding of boehmite decreases average pore size because of the blocking of macro pores by superabundant fine crystals from excessive boehmite. The support sintered at 1500 °C from mixture powders with 5.22% boehmite has an open porosity of 53.73%, an average pore size of 5.1 μm, and a bending strength of 35.5 MPa. Furthermore, because of its high purity, the sample is likely to have good resistance to acid and alkali corrosion.