Abstract: The leaching behaviors of aluminum and silicon compounds in aluminum-rich fly ash generated in circulating fluidized bed in dilute alkaline solution were studied. The physical and chemical properties of the ash were determined. And the effects of alkaline concentration, reaction temperature and reaction time on performances of silica and alumina were investigated. The results show that the ash is composed of various irregular porous particulates which are more active. Alumina and silica in the ash behave quite differently in a mild process occurred in alkaline dissolution. On the conditions of reaction temperature 95℃, NaOH concentration 150 g/L and reaction time 90 min, there is a biggest difference between the performance of alumina and silica in the ash. The mass ratio of Al2O3 to SiO2 in the ash can be raised from 0.78 to 0.99, with extraction rate of SiO2 and Al2O3 reaching the levels of 23.15% and 1.68% respectively.

Key words: aluminum-rich fly ash, alumina, silica, alkaline solution, pre-desilication

摘要： 研究了循环流化床锅炉高铝粉煤灰中铝和硅在NaOH稀溶液中的浸出行为，在对高铝粉煤灰的组成、物相等物化性质研究的基础上，考察了碱浓度、反应温度和反应时间等工艺参数对粉煤灰中铝硅反应性能的影响. 结果表明，粉煤灰为大小不一的不规则颗粒，疏松多孔，具有较高的反应活性；在温和条件下，碱溶液中铝硅溶出规律存在较大差异，在95℃、碱浓度为150 g/L、反应90 min时二者差异最大，SiO2溶出率可达23.15%，而Al2O3的溶出率仅为1.68%，粉煤灰的铝硅比可由0.78提高到0.99.

关键词: 高铝粉煤灰, 氧化铝, 二氧化硅, 碱溶液, 预脱硅