高岭土为助烧剂制备多孔陶瓷膜支撑体

PREPARATION OF Al_2O_3 CERAMIC MEMBRANE SUPPORT USED KAOLIN AS SINTERING AID

陶瓷膜分离技术广泛应用于石油化工,食品加工,生物医学,催化过滤等领域。目前,陶瓷膜的多孔支撑体主要以氧化铝为原料。为保持较小的渗透阻力,通常使用大粒径氧化铝的,其煅烧时需要很高的温度,能耗很高,导致多孔支撑体的成本很高。为降低其制备成本,本文采用以刚玉粉(W40,平均粒径为40μm)为主要原料,以高岭土,滑石等为塑性剂和助烧剂,研究了助烧剂含量、烧结温度对多孔陶瓷支撑体的抗折强度,孔隙率以及平均孔径的影响。实验结果表明:高岭土含量的增加会导致多孔陶瓷的孔径降低和抗折强度降低;加少量的烧滑石能明显降低多孔陶瓷的烧结温度;90wt%W40粉,2wt%烧滑石,8wt%高岭土,经1510℃煅烧2h后得到的多孔陶瓷的抗折强度为153.6MPa,孔隙率为29%,平均孔径为6.6μm。所得多孔陶瓷适于用作多孔陶瓷膜支撑体。

Ceramic membrane separation technology is widely used in industry area, such as petroleum chemical industry, food, biological medicine, catalytic and filter, etc. At present, the support of ceramic membranes is usually prepared using A1203 as raw materials. To decrease the penetration resistance, alumina with large particle size is needed. However, the calcinations of this alumina powder needs the high temperature and high energy consumption, resulting in the high order to reduce the cost of its preparation, this paper cost of the porous support of ceramic membrane. In use alumina powder （W40, the average particle size is 40 μ m） as main raw materials, the kaolin and talc as plastic agent and sintering-aid agent. The effect of the content of the sintering-aid, the sintering temperature on the bending strength, the porosity and the pore size distribution are discussed. The experimental results show that the pore size and the bending strength of the support decrease with the increase of the content of kaolin. The addition of talc could obviously decrease the sintering temperature of porous ceramics. The support of 90 wt % W40 alumina powder, 2wt% talc, 8wt% kaolin, sintered at 1510°C for 2h has the bending strength of 153.6 MPa, the porosity is 29%, and the mean pore size is 6.6um, which is suitable for used as porous ceramics membrane support.