利用高铝粉煤灰制备氧化铝的实验研究

Study of Preparation of Aluminum Oxide from High-alumina Fly Ash

以高铝粉煤灰为原料,以Na2CO3为配料,通过对粉煤灰焙烧,熟料中硅、铝分离,二氧化碳酸化偏铝酸钠溶液等操作制备氢氧化铝。再经煅烧,制备得到氧化铝。实验结果表明,以Na2CO3为配料经中温焙烧,可以将粉煤灰中的莫来石、玻璃相等分解,并转化为霞石(NaAlSiO4),粉煤灰的分解率达到98.96%;用6.73mol/L的HCl溶液浸取焙烧后的熟料,可以使熟料中氧化铝最大程度地分离,且分离率达96.73%;分离后得到的氯化铝溶液进行碱中和,向得到的偏铝酸钠溶液通入二氧化碳,得到Al(OH)3沉淀;氢氧化铝经过煅烧,即可得到氧化铝产品。

The aluminum oxide was prepared from high-alumina fly ash, with Na2CO3 as an auxiliary agent, and the decompose degree of the fly ash was up to 98.96%, lixiviating aluminum oxide from silicon dioxide in hydrochloric acid solution, and the separation degree of the aluminum oxide was 96.73%, neutralizing aluminate sodium by CO2 to prepare aluminum hydroxide. The experimental results indicated that the fly ash was decomposed by Na2CO3, silicon dioxide and aluminum oxide can be separated by hydrochloric acid, and sintering aluminum hydroxide to prepare γ-Al2O3.