包覆型Al_2O_3粉体制备低温烧成多孔陶瓷膜支撑体

采用22μmα-Al2O3为骨料,0.5μmα-Al2O3为烧结助剂,一是采用简单机械混合得到上述2种氧化铝的混合粉体,二是通过粉体表面修饰的方法,将0.5μmα-Al2O3包覆在22μmα-Al2O3表面得到包覆型氧化铝粉体。采用上述2种原料,通过干压成型法制备出片状多孔支撑体,考察了不同烧成温度下2种粉体路线制备出的多孔支撑体的弯曲强度、平均孔径、孔隙率和纯水通量。结果表明:在获得相同支撑体性能的前提下,以包覆型氧化铝粉体为原料制备出的支撑体的烧成温度大大低于采用简单机械混合后粉体制备支撑体的。在1550℃的烧成温度下,包覆型氧化铝粉体制备的支撑体的机械强度为34.2MPa,孔隙率为34%,平均孔径为2.34μm,纯水通量为205m3/(m2·h·MPa)。

POROUS CERAMIC SUPPORT OF COATED ALUMINA PREPARED BY LOW-TEMPERATURE SINTERING

Two kinds of alumina powders with a mean particle size of ～22μm (micro) and ～0.5μm (submicrometer) respectively were chosen as the starting materials. Two methods to treat the alumina powders suitable for macroporous support preparation were used. With one method, the powder mixture of the micro and submicrometer alumina powders is obtained through simple mechanical mixing, and with the other, the micrometer alumina is coated with submicrometer alumina via heterocoagulation process. By using these two post-treated alumina powders, respectively, two kinds of disk supports were prepared by dry-pressing. The effects of the sintering temperature on the properties of these supports, such as the bending strength, pore structure and pure water flux, were studied. The results show that the bending strength of the support prepared with coated alumina (hereafter referred to as support CS) is higher than that of the support prepared with the powder mixture. The support CS sintered at 1 550℃ exhibits higher mechanical strength and permeability as follows: a bending strength of 34.2MPa and a pure water flux of 205m~3/(m~2·h·MPa), and its average pore size and porosity are 2.34μm and 34%, respectively.