利用高铝粉煤灰制备氢氧化铝的实验

Preparation of Aluminum Hydroxide from High-alumina Fly Ash:An Experimental Study

以无水碳酸钠为助剂，分解高铝粉煤灰中的莫来石和铝硅酸盐玻璃相。经中温烧结、酸浸使硅铝分离，调节pH值为5～6纯化含铝滤液，通入CO2气体酸化等工序，可制备氢氧化铝粉体。采用X射线粉末衍射、扫描电镜、化学分析方法对制品进行表征，结果表明：制备的氢氧化铝为球形颗粒，其粒径为200nm左右，性能达到GB／T4294-1997的三级标准。实验所采用的工艺路线是高铝粉煤灰资源化高效利用的有效途径之一。

With sodium carbonate as an auxiliary agent to decompose the mullite and aluminosilicate glass phases of high-alumina fly ash from a coal power plant in northern China, the aluminum hydroxide was prepared by sintering the raw materials at intermediate temperature, acid-leaching to separate silica and alumina from the sintered materials, adjusting the pH value of the filtered aluminum chloride solution ranging from 5 to 6 to purify the filtrate, and acidifying by entrance of CO2. XRD, SEM and chemical analysis methods were used to characterize the aluminum hydroxide product. The experimental results indicated that the prepared aluminum hydroxide, with granular size around 200 nm in diameter, was spherical particles in shape, and satisfied with the China National Chemical Standard GB/T4294-1997. These results demonstrate that this technique is industrially feasible to utilize this sort of high-alumina fly ash as a potential alumina resource in the future.