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采用KCl作为添加剂,根据差示扫描量热仪(DSC)测得的DSC曲线,对非等温动力学微分方程采用Achar-Brindley-Sharp-Wendworth法拟合实验数据,逻辑选择确定KCl-Na OH混合碱熔分解锆英砂的最可几微分机制函数及动力学参数,并对碱熔分解过程进行动力学分析。研究结果表明:KCl-Na OH混合碱熔分解锆英砂在分解深度为0.01~0.09范围内时,最可几微分机制函数为f(a)=(1-a)2,表观活化能和指前因子分别为199.7 k J·mol-1和1×1010.39s-1。当分解深度为0.29~0.60时,最可几微分机制函数转变为f(a)=3/2[(1-a)-1/3-1]-1,表观活化能和指前因子转变为139.25 k J·mol-1和1×108.52s-1。KCl的加入改变了碱熔分解反应的表观活化能和指前因子,使得碱熔分解反应表观活化能降低,碱熔体系的反应速率增大。KCl-Na OH混合碱熔分解锆英砂反应在609~665℃时,为化学反应控速。随着碱熔分解反应的继续进行,当反应温度为730~811℃时,锆英砂表面不断被产物层包裹,反应机制转变为三维扩散,球形对称,扩散控制过程。
Using KCl as an additive, the experimental data were fitted by the Achar-Brindley-Sharp-Wendworth method for non-isothermal kinetic differential equations according to the DSC curve measured by differential scanning calorimetry (DSC). The KCl-Na OH mixture The most probable mechanism function and kinetic parameters of alkali dissolution zircon oil are analyzed, and the kinetic analysis of alkali melting process is carried out. The results show that the most probable mechanism function of kinetic decomposition of zircon sand with KCl-Na OH is f (a) = (1-a) 2 when the decomposition depth is in the range of 0.01 ~ 0.09. The apparent activation energy and The pre-exponential factors were 199.7 kJ · mol-1 and 1 × 1010.39s-1, respectively. When the decomposition depth is 0.29 ~ 0.60, the most probable derivative mechanism function changes to f (a) = 3/2 [(1-a) -1 / 3-1] -1. The apparent activation energy and pre-exponential factor transition Was 139.25 kJ · mol-1 and 1 × 108.52s-1. The addition of KCl changes the apparent activation energy and the pre-exponential factor of the alkali-melting decomposition reaction, so that the apparent activation energy of the alkali-melting decomposition reaction decreases and the reaction rate of the alkali-melting reaction system increases. KCl-Na OH mixed alkali melting zircon sand reaction at 609 ~ 665 ℃, for the chemical reaction rate. With the continued alkali melting reaction, when the reaction temperature is in the range of 730 ~ 811 ℃, the surface of zircon sand is continuously surrounded by the product layer, and the reaction mechanism is transformed into a three-dimensional diffusion, spherical symmetry and diffusion control process.