摘要
粉煤灰中Si、Al聚合能力大,活性差,综合利用困难。论文针对目前所报道的粉煤灰活化焙烧提铝方法中存在的诸如活化助剂及酸用量大、易产生腐蚀性有害气体等不足,开展粉煤灰活化提铝工艺条件研究。通过实验,筛选并确定CaCl_2+Ca(OH)_2为较适宜的复合活化助剂;考察并确定了较适宜的活化焙烧工艺条件为:m(粉煤灰∶CaCl_2∶Ca(OH)_2)=2∶1∶0. 2、焙烧时间1. 5h、焙烧温度800℃;考察并确定了较适宜的酸浸工艺条件为:反应温度95℃、反应时间3. 5h、ω(H_2SO_4)=33%、液固比=3∶1。优化条件下活化焙烧后粉煤灰中氧化铝浸出率达到95. 5%,且酸浸液中残留酸占比低于5%,无需循环酸浸。通过活化焙烧所得粉煤灰熟料、酸浸滤饼的结构表征,对复合活化助剂的作用机制进行了初步探讨。
Si and Al are difficult to be extracted from fly ash due to their high polymerization property and poor activity.Facing the deficiencies such as high addition of activator and acid,generation of corrosive and harmful gases in the activated calcination and extraction of aluminum from fly ash,the extracting conditions of aluminum from fly ash using compound activator was studied.CaCl2 plus Ca(OH)2 was selected as the more suitable compound activator for the calcination of fly ash,and the activated calcination conditions were optimized as follows:mass ratio of fly ash to CaCl2 to Ca(OH)2=2∶1∶0.2,calcination time 1.5h,calcination temperature 800℃.The leaching conditions were optimized as follows:reaction temperature 95℃,reaction time 3.5h,the concentration of H2SO4 33%(wt%),the liquid-solid ratio 3∶1.Under this condition,the leaching rate of Al2O3 in the calcined fly ash could reach 95.5%and the ratio of the residual acid in the leachate was controlled below 5%,and no cyclic acid leaching is required.The action mechanism of the compound activator on the fly ash was preliminarily discussed through the characterization of the calcined fly ash and leaching filter cake.
作者
王百年
宛强
阳春娇
董胤喆
杨保俊
Wang Bainian;Wan Qiang;Yang Chunjiao;Dong Yinzhe;Yang Baojun(School of Chemistry and Chemical Engineering,Hefei University of Technology,Hefei 230009,China)
出处
《轻金属》
北大核心
2019年第1期18-24,共7页
Light Metals
关键词
粉煤灰
活化焙烧
酸浸
AL2O3
fly ash
activated calcination
acid leaching
Al2O3