Leaching Behaviors of Aluminum and Silicon Compounds in Aluminum-rich Fly Ash in Dilute Alkaline Solution
BO Chun-li ZHENG Shi-li MA Shu-hua XIE Hua
School of Chemical & Environmental Engineering, China University of Mining & Technology Institute of Process Engineering, Chinese Academy of Sciences Institute of Process Engineering, Chinese Academy of Sciences (1. School of Chemical & Environmental Engineering, China University of Mining & Technology
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.
2012, Vol. 12 
