多相氢氧化铝向薄水铝石相转变过程的微观结构研究

以铝直接水解法所得氢氧化铝粉为原料,经水热处理获得了纯相的薄水铝石粉体。研究了水热反应温度对产物γ-AlOOH晶体结构及微观形貌的影响,并利用XRD、SEM、TEM、HRTEM、粒度分布和TG-DSC对样品的物相、微观形貌及晶相转变过程进行分析表征。结果表明,水热温度对于制备纯相薄水铝石发挥重要作用,且有利于优化合成条件。随着水热温度的升高,物质结构转变动力也随之增强,可实现由多相氢氧化铝向纯薄水铝石相转变。利用CASTEP软件分别对薄水铝石、拜耳石及诺耳石体系进行几何优化,计算各体系的总能量。证实在同一计算精度下,薄水铝石的总能量最低,说明该体系最稳定。

Study on microstructure of multiphase aluminum hydroxide transition to boehmite phase

Boehmite(γ-AlOOH)powder is synthesized by hydrothermal method using aluminum hydroxide products as raw materials.The effect of the hydrothermal temperature on the crystal structure and morphology are investigated.The crystal structure,morphology and the phase transition process of the samples are discussed detailedly via XRD,SEM,TEM,HRTEM,particle size distribution and TG-DSC.The results indicate that hydrothermal treating temperature plays an important role on obtaining well-crystallized boehmite particles,which is useful for optimizing the synthesis condition.With the increase of hydrothermal treating temperature,the dynamics of material structure transformation are also enhanced,therefore,the phase transition process from multiphase aluminum hydroxide to pure boehmite can be realized.Moreover,the CASTEP program module is used to optimize the geometry of boehmite,bayerite and nordstrdite systems,and the total energy of each system are calculated.The calculation results of total energy indicate that boehmite is steadier than the other two according to energy.