Abstract:

In order to get the mechanism of hausmannite prepared by the decomposition of manganese sulfate in air, the thermal decomposition behavior of manganese sulfate was studied with TG-DSC and XRD, and the kinetics of dehydration and decomposition was studied with non-linear iso-conversional method and the universal integral method.Mampel Power principle G(α)=α^3/2 was used to describe the dehydration kinetics of manganese sulfate between 200℃ and 400℃.The average activation energy of the dehydration was calculated to be 117.11 kJ·mol^-1.MnSO4 was decomposed to form Mn3O4 while the temperature was between 750℃and 1050℃.The decomposition kinetics could be described as G(α)=1-(1-α)^1/2, and its average activation energy was 226.44 kJ·mol^-1.The result of isothermal decomposition kinetics of manganese sulfate agreed with its non-isothermal kinetics by TG-DSC analysis.

Key words:

硫酸锰, 四氧化三锰, 热分解动力学, 非线性等转化率法

摘要：

为了确定空气中硫酸锰分解生成四氧化三锰的机理，用TG-DSC结合XRD分析研究了硫酸锰的热分解行为，用非线性等转化率法和普适积分法研究了硫酸锰脱水和分解过程的反应动力学。研究结果表明，200～400℃之间为MnSO4·H2O脱水阶段，积分动力学机理函数为G(α)=α^3/2, 符合Mampel Power法则，平均表观活化能为117.11 kJ·mol-1;750～1050℃之间为MnSO4的分解阶段，积分动力学机理函数为G(α)=1-(1-α)1/2，符合相边界反应的收缩圆柱体模型，平均表观活化能为226.44 kJ·mol-1，MnSO4等温分解结果与TG-DSC分析结果一致。

关键词:

硫酸锰, 四氧化三锰, 热分解动力学, 非线性等转化率法