高温悬浮态下石灰石与菱镁矿热分解特性比较及动力学研究

Comparison of the decomposition characteristics and kinetics of magnesite with limestone under high temperature suspension state

利用悬浮态高温炉,对比研究了菱镁矿及石灰石的热分解特性,探讨了其热解模型及动力学参数。结果表明:低温段(650~750℃)时,菱镁矿比石灰石易分解,达到一定高温后其分解速率相差不大;菱镁矿、石灰石在悬浮态下的热解机理均符合收缩核模型,其活化能分别为50 kJ/mol、79 kJ/mol;随着菱镁矿粒度的增大,其分解速率趋缓,分解表观活化能增大。

The thermal decomposition characteristics of magnesite and limestone were studied by using the high temperature furnace,and the pyrolysis model and kinetic parameters were discussed.The results show that the magnesite is easier to decompose than limestone in the low temperature range（650-750℃）,and the decomposition rate is similar after reaching a certain high temperature.The decomposition rate of the magnesite or limestone in the suspended state is consistent with the shrinkage model,and the activation energy is 50 kJ/mol and 79 kJ/mol respectively.With the increase of the size of magnesite, the decomposition rate decreased and the apparent activation energy increased.