title: Reaction-sintered porous mineral-based mullite ceramic membrane supports made from recycled materials.
abstract: 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.
authors: Key Lab of Jiangxi Universities for Inorganic Membranes, National Engineering Research Center for Domestic and Building Ceramics, Jingdezhen Ceramic University (JCU), Jingdezhen, Jiangxi 333001, PR China. dongyc9@mail.ustc.edu.cn
authors: Yingchao
authors: Y
authors: Dong
authors: Jian-Er
authors: JE
authors: Zhou
authors: Bin
authors: B
authors: Lin
authors: Yongqing
authors: Y
authors: Wang
authors: Songlin
authors: S
authors: Wang
authors: Lifeng
authors: L
authors: Miao
authors: Ying
authors: Y
authors: Lang
authors: Xingqin
authors: X
authors: Liu
authors: Guangyao
authors: G
authors: Meng
mesh_terms: D000538:Aluminum Silicates / Q000737:chemistry*; D002244:Carbon; D002516:Ceramics / Q000737:chemistry*; D060729:Coal Ash; D003247:Conservation of Natural Resources; D005740:Gases; D007700:Kinetics; D008567:Membranes, Artificial; D008855:Microscopy, Electron, Scanning / Q000379:methods; D009584:Nitrogen / Q000737:chemistry; D052638:Particulate Matter; D016062:Porosity; D013314:Stress, Mechanical; D013696:Temperature; D013997:Time Factors; D018508:Water Purification / Q000379:methods; D014961:X-Ray Diffraction
chemical_list: D000538:Aluminum Silicates; D060729:Coal Ash; D005740:Gases; D008567:Membranes, Artificial; D052638:Particulate Matter; C049037:aluminosilicate; D002244:Carbon; D009584:Nitrogen