Abstract:

Adopting aluminum hydroxide as the raw material to prepare α-Al₂O₃,the phase transformation process and microstructure changes of aluminum hydroxide at different calcination temperatures (500,800,900,1 100,1 200,and 1 300 ℃) were studied.The results show that:(1) at 500 ℃,a part of gibbsite loses crystal water and transforms into boehmite;at 500-800 ℃,gibbsite and boehmite continue to lose crystal water and convert into alumina transition phases;(2) at 800-1 200 ℃,phase transformation occurs between alumina transition phases;at 1 300 ℃,all transition phases transform into α-Al₂O₃;(3) when the calcination temperature is 800 ℃,the specific surface area of γ-Al₂O₃ to η-Al₂O₃ is the largest and the activity is the highest,which provides a new way for the catalyst support and the improvement of the cycle life of the battery.

Key words: aluminum hydroxide, gibbsite, boehmite, alumina

摘要：

为研究氢氧化铝制备α-Al₂O₃过程中的相转变和微观结构的变化,以氢氧化铝为原料,研究了不同煅烧温度(500、800、900、1 100、1 200、1 300 ℃)下氢氧化铝的相变过程和显微结构的变化。结果表明:1)在500 ℃时,一部分三水铝石脱除结晶水转化为一水软铝石;500~800 ℃时,三水铝石和一水软铝石继续脱除结晶水转化为氧化铝过渡相。2)在800~1 200 ℃时,氧化铝过渡相之间进行相转变;1 300 ℃时,过渡相全部转化为 α-Al₂O₃。3)煅烧温度为800 ℃时生成的γ-Al₂O₃和η-Al₂O₃比表面积最大,活性最高,为催化剂载体和提高电池循环寿命提供了新途径。

关键词: 氢氧化铝, 三水铝石, 一水软铝石, 氧化铝