为了降低高纯Al2O3(α-Al2O3质量含量≥99%)多孔陶瓷膜支撑体烧成温度,以粒径为30μm的α-Al2O3为原料,分别添加TiO2和TiO2/Cu(NO3)2为烧结助剂,通过干压成型和挤出成型制备片状和管式多孔支撑体。Al2O3-TiO2和Al2O3-TiO2-CuO体系分别在高温下出现的液相低共熔物促进了多孔支撑体的烧结。当氧化铝支撑体中添加0.5%(摩尔分数,下同)TiO2+0.5%Cu(NO3)2后,在1600℃的烧成即可获得机械性能高、渗透性能好和耐酸碱腐蚀性能优异的管式支撑体。在压力为0.1MPa时,支撑体的水渗透通量为12.1m3/(m2·h),弯曲强度为44.5MPa。经过80℃,含10%(质量分数,下同)HNO3的溶液腐蚀800h及80℃,含10%NaOH的溶液1200h后,支撑体的质量损失率分别为1%和0.35%。
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.The support with a composition of 99%Al2O3,0.5% (in mole,the same below) TiO2 and 0.5% Cu(NO3)2 sintered at 1 600 ℃ has high permeability,comparative high mechanical strength as well as excellent corrosion-resistant property.The properties of the support 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 ℃ for 800 h) or 10% NaOH (80 ℃ for 1 200 h),the mass losses of the support are 1.0% and 0.35%,respectively,which indicates it has an excellent corrosion-resistant properties towards hot HNO3 and NaOH.