【摘要】 采用Netzsch STA409PC同步热分析仪研究了苏州高岭石（KW125）在30℃～1 200℃间的热分解过程。采用"Netzsch Thermokinetics software"软件对其脱羟基机理进行了非等温动力学研究。基于等转化法评价了反应活化能及反应进程的依存关系。基于多元非线性拟合确定了最可能反应机理及动力学参数。研究结果表明:苏州高岭石在30℃～1 200℃温度范围的热分解为脱羟基与相转变等两个阶段。其脱羟基（30℃～800℃）过程中活化能呈现三个变化:197.68 kJ/mol±12.95 kJ/mol→181.04 kJ/mol±18.98 kJ/mol→269.7 kJ/mol±14.64 kJ/mol。脱羟基反应遵循三步连续反应模型t:f,f;（D₃-F_n-F_n）,一个三维扩散（D₃）反应,然后是两个n序列（F_n）反应。第一步,f（α）=3（1-α）^2/3/(2(1-（1-α）^1/3),E₁=185.27 kJ/mol,logA=10.83 s^-1;第二步,f（α）=（1-α）ⁿ,n=1.75,E₂=187.81 kJ/mol,logA=10.32 s^-1;第三步,f（α）=（1-α）ⁿ,n=4.4,E₃=262.70 kJ/mol,logA=13.26 s^-1。更多还原

【Abstract】 The thermal decomposition of Suzhou kaolinite below 1 200 ℃was investigated by simultaneous thermal analyzer.Non-isothermal kinetic analysis was employed to study the dehydroxylation mechanism by using Netzsch Thermokinetics software.The dependence of activation energy on the reaction process was evaluated based on the isoconversional method,and the probable mechanism as well as the corresponding kinetic parameters was determined on the basis of multivariate non-linear regression program. It was showed that the thermal decomposition of Suzhou kaolinite was divided into two stages of dehydroxylation and phase transformation. During kaolinite dehydroxylation,three activation energy changes were recognized as 197.68→181.04→269.7 kJ/mol.The dehydroxylation reaction was controlled by three consecutive mechanisms t:f,f;（D₃-F_n-F_n）,a three-dimensional diffusion（D₃ mode） reaction followed by two n-order（F_n mode） reactions. The first step was f（α）=(3（1-α）2/3/（2（1-（1-α）1/3））,E₁=185.27 kJ/mol, logA=10.83 s^-1;the second step f（α）=（1-α）ⁿ,n=1.75,E₂=187.81 kJ/mol,logA=10.32 s^-1 and the third step was f（α）=（1-α）ⁿ,n=4.4,E₃=262.70 kJ/mol,logA=13.26 s^-1.更多还原