以氧化铝为骨料真空热分解碳酸锂的正交实验及动力学过程分析

Orthogonal experiment and kinetic analysis of thermal decomposition of Li 2CO3 with Al2O3 as aggregate in vacuum

为促进碳酸锂热分解过程,制备适用于熔盐电解法生产铝锂合金的氧化物原料,本文研究了以氧化铝为骨料真空热分解碳酸锂以制备铝锂复合氧化物的工艺过程及反应行为.通过正交实验,分别考查了煅烧时间、制团压力、物料粒度等工艺参数对碳酸锂分解率的影响.结果表明,通过正交实验得到最佳的实验条件为熟料与碳酸锂质量配比3∶1,制团压力45MPa,物料粒度150μm,煅烧时间5h,煅烧温度850℃,该条件下碳酸锂分解率最高可达74.71%.通过对碳酸锂热分解反应的动力学分析表明,真空条件下碳酸锂分解反应平均表观活化能为146.23kJ/mol,其反应级数为1.Li2CO3分解生成CO2的机理模型为化学反应,减速形曲线,函数为g(α)=(1-α)-2.

To promote the thermal decomposition process of lithium carbonate to prepare oxide materials suitable for the preparation of lithium aluminum alloy by molten salt electrolysis,the technological process and reaction behavior of Li 2CO 3 thermal decomposition with alumina as aggregate under vacuum for producing aluminum-lithium composite oxide were studied.Through orthogonal experiments,the effects of process parameters such as calcination time,briquetting pressure,and material particle size,on the decomposition rate of Li 2CO 3 were investigated.The optimum conditions via orthogonal experiment were obtained.The mass ratio of clinker to lithium carbonate is 3∶1,the mass pressure is 45 MPa,the particle size of material is 150μm,calcination time is 5 h,the calcination temperature is 850℃.The maximum decomposition ratio of lithium carbonate can reach 74.71%under these conditions.Kinetic analysis of lithium carbonate thermal decomposition shows that the average apparent activation energy under vacuum is 146.23 kJ/mol and the reaction order is approximately 1.The mechanism model of Li 2CO 3 decomposition to CO 2 is chemical reaction,with deceleration curve consistent with the function g(α)=(1-α)-2.