菱镁矿热分解的动力学研究  

Thermal Decomposition Kinetics Analysis of Magnesite

作　　者：彭强[1] 郭玉香[1] 曲殿利[1] 

机构地区：[1]辽宁科技大学高温材料与镁资源工程学院,鞍山114000

出　　处：《硅酸盐通报》2017年第6期1886-1890,共5页Bulletin of the Chinese Ceramic Society

基　　金：国家科技支撑计划项目(2014BAB02B01)

摘　　要：利用热重(TG)分析法,对不同粒度菱镁矿的热分解过程进行研究。根据Flynn-Wall-Ozawa法,拟合计算得到不同粒度菱镁矿热分解的活化能和指前因子。采用Thermo-kinetics软件对可能性最大的5种动力学机理函数进行拟合,根据相关系数最大的原则确定最佳分解机理。研究结果表明:菱镁矿热分解的活化能随菱镁矿粒度的增大而减小,当菱镁矿的粒度由小增大时,控制其热分解过程的机理由化学反应逐渐向颗粒内部的传热和CO2的扩散传质转变;其热分解过程的最可几机理函数为R3模型,即三级相边界扩散反应,函数方程为G(α)=1-(1-α)^(1/3)。Decomposition kinetics of different particle size magnesite was investigated by using thermogravimetric （TG） analysis. The activation energy and pre-exponential factor （A） of the decomposition from different particle sizes magnesite were calculated according to the Flynn-Wall-Ozawa method. Determine the optimal decomposition mechanism based on the principle of maximum correlation coefficient by using Thermo-kinetics software fitting to 5 most possibility kinetic mechanism functions. The research results indicate that the activation energy of thermal decomposition of magnesite decreases with the increasing of particle size. With the increasing of particle size of magnesite the mechanism of thermal decomposition process is influenced by the chemical reaction and gradually changed to the heat transfer inside the particle and diffusion of CO2. The most probable reaction mechanism of the thermal decomposition process is a three-dimensional boundary reaction （R3 ）. The kinetic equation is as follows ：G（α）=1-（1-α）^1/3.

关 键 词：菱镁矿 动力学 热重分析 活化能 反应机理函数 

分 类 号：TQ175[化学工程—硅酸盐工业]