Preparation of high purity alumina macroporous support at low sintering temperature

In order to reduce the sintering temperature of pure alumina membrane support with ≥99% in mass α-Al₂O₃, disk and tubular macroporous ceramic supports consisting of alumina, using TiO₂ or TiO₂/Cu(NO₃)₂ as sintering promoter agents, were prepared by dry-pressing and plastic extrusion respectively. The appearance of the liquid eutectic mixture during the sintering process of Al₂O₃-TiO₂ and Al₂O₃-CuO-TiO₂ system is helpful to increase the sintering rate of macroporous alumina supports, which prepared at a sintering temperature below 1700°C exhibit both high mechanical strength and high permeability. In the case of the support with a composition of 99%Al₂O₃, 0.5% (in mole, the same below) TiO₂ and 0.5% Cu(NO₃)₂, a support with combination of high permeability, comparative high mechanical strength as well as excellent corrosion-resistant property can be prepared by sintering at 1600°C, which is lower than that for the pure alumina macroporous support. The properties of this kind of support sintered at 1600°C are as follows: its pure water flux at 0.1 MPa and the three-point bending strength are 12.1 m³/(m²·h) and 44.5 MPa, respectively. When immersed in 10% (mass fraction, the same below) HNO₃ (80°C for 800 h) or 10% NaOH (80°C for 1200 h), the mass losses of such support are 1.0% and 0.35%, respectively, which indicates it has an excellent corrosion-resistant properties towards hot HNO₃ and NaOH.