发泡法和溶胶-凝胶法制备镁质多孔材料  

Preparation of magnesia porous material using foaming method and sol-gel method

作　　者：李美葶 罗旭东[2,3] 张国栋 谢志鹏[3] 李继光[1] 杜健[2] 

机构地区：[1]东北大学材料科学与工程学院,辽宁沈阳110000 [2]辽宁科技大学高温材料与镁资源工程学院 [3]清华大学材料科学与工程系新型陶瓷与精细工艺国家重点实验室

出　　处：《无机盐工业》2017年第1期19-21,55,共4页Inorganic Chemicals Industry

基　　金：国家自然科学基金资助(51402143)

摘　　要：对比分析了发泡法和溶胶-凝胶法制备镁质多孔材料的组成、结构及性能。发泡法制备镁质多孔材料是以菱镁矿浮选尾矿和电熔镁砂为主要原料,加入六偏磷酸钠、柠檬酸钠及α-氧化铝粉为添加剂,并以十二烷基磺酸钠发泡和糊精稳泡的方式制备预混料浆,经注浆成型、养护、干燥及烧成工序制得多孔材料。溶胶-凝胶法制备氧化镁多孔材料是以六水氯化镁为前驱体,以聚氧乙烯(PEO)为相分离诱导剂及环氧丙烷(PO)为凝胶促进剂,经过陈化、干燥及烧成工序最终得到氧化镁多孔材料。结果表明:发泡法制备多孔材料的气孔尺寸可控,大多为封闭气孔,且生产工艺过程简单,同时以菱镁矿浮选尾矿为主要原料,大大缩短了生产成本。与发泡法相比,溶胶-凝胶法制备的氧化镁多孔材料结构更为疏松,形成的凝胶骨架使得基体韧性增强,烧成后形成三维网络贯通气孔,气孔孔径细小且均匀,气孔尺寸多为纳米级,此外烧后试样全部为方镁石相。The composition, structure, and property of magnesia porous materials prepared by foaming method and sol-gel method were compared and analyzed.Magnesia porous material by foaming method was prepared with main raw materials including flotation tailing of magnesite and fused magnesia as well as additives involving hexametaphosphate, sodium citrate and α-Al2O3 powder.The slurry of magnesia porous material was prepared with sodium dodecyl sulfate （SDS） as blowing agent and dextrin as foam stabilizer, and magnesia porous materials were produced through the processes, including slip casting, curing, drying, and sintering.Magnesia porous material prepared by sol-gel method was accompanied by phase separation with MgCl2· 6H2O as a precursor, poly （ethylene oxide ） （PEO） as a phase separation inducer and propylene oxide （PO） as a gelation agent.Then magnesia porous materials were prepared by ageing,drying, and sintering processes.Results showed that the pore size of porous material could be controlled via foaming method, pores were mostly closed, and the way of production process was simple.While using magnesite flotation tailings as the main raw material can greatly reduce the cost of production and achieve sustainable development of resources.Compared with foaming method,the structure of MgO porous materials via sol-gel method was loose, gel skeletons enhanced the matrix toughness, three-dimensional network through-hole was formed after sintering, and the pore diameter small, uniform and mostly nanoscale.Besides, the crystalline composition of specimens after sintering was all comprised of periclase.

关 键 词：发泡法 溶胶-凝胶法 镁质多孔材料 凝胶骨架 

分 类 号：TQ132.2[化学工程—无机化工]