保温时间对低温烧成管式多孔陶瓷膜支撑体性能的影响

Effect of Holding Time on Properties of Macroporous Support Sintered at Low Temperature

采用平均粒径为30μm的α-Al2O3和TiO2为原料,通过塑性挤出法制备出管式多孔支撑体。考察了支撑体在1 400℃保温不同时间烧成后的线性收缩、体积密度、孔结构、渗透性能和弯曲强度,并研究了支撑体的形成机理。结果表明:支撑体在1 400℃烧成时,Al2O3和TiO2反应生成Al2TiO5,该反应的进行程度对支撑体渗透性能和力学性能有决定性影响。在1 400℃保温2 h烧成后,支撑体具有较高的机械强度(32.7 MPa)、较高的渗透通量[在0.1 MPa压力下为45 m3/(m2.h)]和较大的平均孔径(6.8μm),且该支撑体经90℃,1%(质量分数)NaOH溶液腐蚀720 h后机械强度基本不变,适宜作为陶瓷微滤膜的载体。

Tubular macroporous supports were fabricated using alumina（α-Al2O3） and titanium dioxide（TiO2） as starting materials via a plastic extrusion method.The effect of the holding time on the linear shrinkage,bulk density,pore structure,permeability and three-point bending strength of the supports at a sintering temperature of 1 400 ℃ was investigated.The formation mechanism of the promising macroporous support was also preliminarily analyzed.The results show that the solid state reaction between Al2O3 and TiO2 at 1 400 ℃ favors greatly to obtain a support with integrated properties of high permeability and sufficient mechanical proper-ties.The properties of the support sintered at 1 400 ℃ for 2 h are the pure water flux of 45 m3/（m2·h） at 0.1 MPa,the average pore size of 6.8 ？m and the three-point bending strength of 32.7 MPa,respectively.There is little variation of bending strength of the supports immersed in 1%（in mass） NaOH（90 ℃ for 720 h）,indicating that the support can be used as a microfiltration membrane support due to its excellent corrosion-resistant property in hot NaOH.