溶析法分解铝酸钠溶液制备氢氧化铝

Decomposing Sodium Aluminate by Solventing-out Process to Prepare Aluminium Hydroxide

提出了一种新的采用溶析法分解铝酸钠溶液制备氢氧化铝的方法,成功制备了超细氢氧化铝。考察了分解温度、铝酸钠溶液浓度、分子比、溶析剂体积比等工艺参数对铝酸钠溶液分解率的影响,发现在常温下,Al2O3100-200g/L、分子比1.4-2.0的铝酸钠溶液与同体积的溶析剂反应,铝酸钠分解率大于90%。运用激光粒度分析仪、SEM、XRD、TG-DTA对粒子的性能进行了表征,结果表明产品为拜耳石片状晶体,产品晶型完整、粒度分布均匀、纯度高。

The novel method of decomposing sodium aluminate solution to aluminium hydroxide using solventing-out crystallization has been proposed and ultra-fine aluminium hydroxide particles were prepared by the method. Effects of crystallization temperature, solution concentration, molar ratio and volume ratio of the solventing-out process were investigated. The experimental results indicated that qualified particles with the decomposition rate of more than 90% were obtained at the condition of lower crystallization temperature, 1 ： 1 volume ratio solvent, sodium aluminate solution concentration of 100-200g/L Al2O3 with the molar ratio of 1.4-2.0. In addition, the obtained product was characterized by SEM, laser diffraction-based particle size analyzer, XRD and TG-DTA. The results showed that the product was bayrite tabular crystal with uniform morphology, narrow particle size distribution and high purity.