Abstract: Boehmite was prepared from supersaturated sodium aluminate solution with ethanol-water solvent. The effects of mass ratio of ethanol (w) and temperature on decomposition rate, diameter and phase composition of alumina hydrate, precipitated from supersaturated sodium aluminate solution were studied, and the obtained product was characterized. The results indicated that the mass ratio of AlOOH in the product increased significantly with the increase of mass ratio of ethanol because of the reduction of free caustic concentration and increase of initial supersaturation coefficient. When w=1.0, the mass ratio of AlOOH in the product reached the peak of 90%. The decomposition rate of supersaturated sodium aluminate solution and mass ratio of AlOOH in the product increased with the decrease of temperature. The addition of ethanol changed growth speeds of product in longitudinal and radial direction and the product changed from plate like crystals to long column agglomerates.

Key words: sodium aluminate solution, ethanol precipitation, boehmite, gibbsite

摘要： 利用铝酸钠溶液乙醇分解法制备了一水软铝石，研究了乙醇溶液中乙醇的质量分数和分解温度对分解过程铝氧水合物分解速率、物相组成的影响，并对产物进行了表征. 结果表明，随着乙醇质量分数的增加、铝酸钠溶液游离碱含量降低、初始过饱和系数增加，一水软铝石析出速率加快；乙醇质量分数为1.0时，分解产物中一水软铝石质量分数达到最大(90%). 铝酸钠溶液分解速率及一水软铝石的质量分数随分解温度的降低而升高. 乙醇改变了铝氧水合物的径向和轴向生长速率，产物由不规则的片状晶体转变为由长柱状晶体组成的附聚体.

关键词: 铝酸钠溶液, 乙醇分解, 一水软铝石, 三水铝石