煤粉炉高铝粉煤灰碱溶脱硅反应动力学  

Kinetics of desilication process of fly ash with high aluminum from pulverized coal fired boiler in alkali solution

作　　者：贺实月 李会泉[2] 李少鹏[2] 李勇辉[2] 解强[1] 

机构地区：[1]中国矿业大学(北京)化学与环境工程学院,北京100083 [2]中国科学院过程工程研究所绿色过程与工程重点实验室湿法冶金清洁技术国家工程实验室,北京100190

出　　处：《中国有色金属学报》2014年第7期1888-1894,共7页The Chinese Journal of Nonferrous Metals

基　　金：国家"十二五"科技支撑计划项目(2012BAF03B01);国家自然科学基金资助项目(51304184)

摘　　要：以内蒙古中西部地区某电厂煤粉炉高铝粉煤灰为对象,研究NaOH溶液脱除粉煤灰非晶态SiO2过程中搅拌速度、反应温度、NaOH溶液初始浓度对粉煤灰非晶态SiO2浸出率的影响,通过实验数据与液固多相反应缩芯模型拟合的方法确定动力学规律及动力学方程。结果表明:SiO2的浸出过程分为2个阶段,反应前期为表面反应控制,表观活化能为80.15 kJ/mol;反应后期为固膜扩散控制,表观活化能为29.93 kJ/mol。结合动力学实验结果及扫描电镜(SEM)、能谱(EDS)分析可知,随着反应的进行,固相产物逐渐附着于粉煤灰表面形成固膜导致控制步骤转变。Using high-alumintnn fly ash from pulverized coal fired boiler in midwest of Inner Mongolia as an object, the effects of stirring speed, reaction temperature and initial NaOH concentration on the leaching rate of SiO2 in the desilication of fly ash in NaOH solution were studied. The kinetic rules and kinetic equations were confirmed by the experimental data fitting with shrinking core model of liquid-solid multiphase reaction. The results show that there are two stages in the leaching process. Earlier stage is limited by the surface reaction, and the apparent activation energy is 80.15 kJ/mol. Later stage is proven that the internal diffusion on the solid product layer is the rate-controlling step in the leaching process, and the apparent activation energy is 29.93 kJ/mol. The results of the kinetic experiment and SEM, EDS analysis show that solid product attached to the surface of fly ash leads to the rate-controlling step changes with the reaction progress.

关 键 词：高铝粉煤灰 脱硅 浸出 动力学 缩芯模型 

分 类 号：X758[环境科学与工程—环境工程]