(1. 中國礦業(yè)大學(xué)(北京) 化學(xué)與環(huán)境工程學(xué)院，北京 100083；
2. 中國科學(xué)院 過程工程研究所 綠色過程與工程重點(diǎn)實(shí)驗(yàn)室 濕法冶金清潔技術(shù)國家工程實(shí)驗(yàn)室，北京 100190)
摘 要: 以內(nèi)蒙古中西部地區(qū)某電廠煤粉爐高鋁粉煤灰為對象，研究NaOH溶液脫除粉煤灰非晶態(tài)SiO2過程中攪拌速度、反應(yīng)溫度、NaOH溶液初始濃度對粉煤灰非晶態(tài)SiO2浸出率的影響，通過實(shí)驗(yàn)數(shù)據(jù)與液固多相反應(yīng)縮芯模型擬合的方法確定動力學(xué)規(guī)律及動力學(xué)方程。結(jié)果表明：SiO2的浸出過程分為2個階段，反應(yīng)前期為表面反應(yīng)控制，表觀活化能為80.15 kJ/mol；反應(yīng)后期為固膜擴(kuò)散控制，表觀活化能為29.93 kJ/mol。結(jié)合動力學(xué)實(shí)驗(yàn)結(jié)果及掃描電鏡(SEM)、能譜(EDS)分析可知，隨著反應(yīng)的進(jìn)行，固相產(chǎn)物逐漸附著于粉煤灰表面形成固膜導(dǎo)致控制步驟轉(zhuǎn)變。
關(guān)鍵字: 高鋁粉煤灰；脫硅；浸出；動力學(xué)；縮芯模型
（1. School of Chemical and Environmental Engineering,
China University of Mining and Technology Beijing, Beijing 100083, China;
2. National Engineering Laboratory for Hydrometallurgical Cleaner Production Technology,
Key Laboratory of Green Process and Engineering, Institute of Process Engineering,
Chinese Academy of Sciences, Beijing 100190, China）
Abstract:Using high-aluminum 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.
Key words: high-aluminum fly ash; desilication; leaching; kinetics; shrinking core model
