摘要
以拟薄水铝石作前驱物,采用溶胶法制备γ-Al_2O_3;在制备初期添加镧或铈的硝酸盐化合物对氧化铝进行改性;使用BET比表面、DTA、XRD衍射和MAS NMR对样品进行表征。对1 100℃下各样品烧结行为的考察中,从各个样品的崩塌温度、XRD晶相以及St指数发现添加镧或铈化合物都能提高γ-Al_2O_3的抗烧结性和高温稳定性,镧改性样品的效果略优于铈改性样品。通过1000℃下热烧结动力学的研究发现,溶胶法制备样品的烧结机理为体相扩散过程,稀土的加入有效地阻止了氧化铝颗粒内的体相扩散。
Gamma alumina samples were prepared by sol method from pseudo-boehmite and the samples were modified by adding the nitrates of La and Ce at the initial period of preparation. The modified samples were characterized by X-ray diffraction, BET, DTA and MAS NMR analyses. The investigation of their sintering behavior was under 1100℃. It was found that from the collapse temperature, XRD crystal phase and S, index, the addition of rare earth species could improve the anti-sintering and high temperature stability of the alumina, and the La-modified alumina was slightly better than the Ce-modified one. The solid-state reaction kinetics analysis under 1000℃showed that the gamma alumina sintered via volume diffusion mechanism at high temperature, and the process could be effectively alleviated by the addition of La and Ce.
出处
《石油炼制与化工》
CAS
CSCD
北大核心
2003年第5期40-43,共4页
Petroleum Processing and Petrochemicals
