离子膜电解铝酸钠溶液制备超细氢氧化铝

Preparation of superfine aluminum hydroxide by ion-exchange membrane electrolysis

利用离子膜电解铝酸钠溶液的方法制备氢氧化铝,研究制备过程中分解条件和非离子型表面活性剂聚乙二醇对产品氢氧化铝的影响,并通过扫描电镜以及红外光谱分析等检测手段对产品氢氧化铝进行表征。结果表明:当搅拌速度为400 r/min、苛碱浓度为150 g/L、温度为35℃时,氢氧化铝粒度分布情况最好;聚乙二醇的加入有利于制备粒度较细且分散性好的氢氧化铝,且随其添加量的增加,氢氧化铝平均粒径减小;聚乙二醇的最佳添加浓度为0.175 g/L,对应产品氢氧化铝的平均粒径为3.9μm。红外光谱表明:聚乙二醇通过在氢氧化铝表面的吸附作用抑制颗粒间的附聚,离子膜电解铝酸钠溶液的产品为拜耳型氢氧化铝。

Preparation of superfine aluminum hydroxide powders from sodium aluminate solution by ion-exchange membrane electrolysis was investigated. The effect of experimental conditions in precipitation process and the effect of polyethylene glycol dosages on aluminum hydroxide products were studied to achieve the required fineness. The results show that the grain size distribution is best under the process conditions of 35 ℃, alkaline concentration of pregnant liquor 150 g/L, stirring speed 400 r/min. The addition of glycol dosages is beneficial to produce the finer and well-dispersive aluminum hydroxide. The average sizes of aluminum hydroxide were reduced gradually with the increase of the polyethylene glycol dosages. When concentration of the additive in sodium aluminate solution reach 0.175 g/L, the average size of ATH is 3.9 μm. The infrared spectra analysis show that, agglomerative particles were dispersed by the adsorption of polyethylene glycol on the surfaces of the aluminum hydroxide particles. The products of ion-exchange membrane electrolysis from sodium aluminate solution are Bayerite.