Reaction-sintered porous mineral-based mullite ceramic membrane supports made from recycled materials
Reaction-sintered porous mineral-based mullite ceramic membrane supports made from recycled materials
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DOI：
10.1016/j.jhazmat.2009.06.148
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发表时间：
2009-12-15
影响因子：
13.6
通讯作者：
Meng, Guangyao
中科院分区：
文献类型：
--
作者：
Dong, Yingchao;Zhou, Jian-er;Meng, Guangyao
以工业废弃物粉煤灰和铝土矿为原料，采用干压法直接制备多孔莫来石陶瓷膜载体，并在1200 ~ 1550 ℃烧结。研究了烧结温度对多孔莫来石相组成和收缩率的影响。XRD结果表明，在1200 ℃以上发生了二次莫来石化反应。并在1450摄氏度下完成。在烧结过程中，混合物样品首先收缩，然后在1326至1477 ℃之间异常膨胀，最后在1477 ℃以上再次收缩。这种独特的体积自膨胀是由于铝土矿和粉煤灰之间的二次莫来石化反应。通过SEM、孔隙率、孔径分布和氮气渗透通量等测试手段，验证了自膨胀烧结引起的微观结构变化。在自膨胀烧结过程中，随着温度的升高，开孔率和孔径都异常增加，这也导致了氮气流量的增加。得到了开孔率增加的矿物基莫来石载体。此外，烧结的多孔莫来石膜支撑体的热膨胀系数和机械强度进行了表征。(C)2009爱思唯尔有限公司版权所有。
Bulk porous mullite supports for ceramic membranes were prepared directly using a mixture of industrial waste fly ash and bauxite by dry-pressing, followed by sintering between 1200 and 1550 degrees C. The effects of sintering temperature on the phase composition and shrinkage percent of porous mullite were studied. The XRD results indicate that secondary mullitization reaction took place above 1200 degrees C. and completed at 1450 degrees C. During sintering, the mixture samples first shrunk, then expanded abnormally between 1326 and 1477 degrees C, and finally shrunk again above 1477 degrees C. This unique volume self-expansion is ascribed to the secondary mullitization reaction between bauxite and fly ash. More especially, the micro-structural variations induced by this self-expansion sintering were verified by SEM, porosity, pore size distribution and nitrogen gas permeation flux. During self-expansion sintering, with increasing temperature, an abnormal increase in both open porosity and pore size is observed, which also results in the increase of nitrogen gas flux. The mineral-based mullite supports with increased open porosity were obtained. Furthermore, the sintered porous mullite membrane supports were characterized in terms of thermal expansion co-efficient and mechanical strength. (C) 2009 Elsevier B.V. All rights reserved.