菱铁矿在悬浮状态下的热解动力学

Thermal Decomposition Kinetics of Siderite Ore in Suspension Condition

在稀相悬浮状态下采用等温法研究了温度和气氛对菱铁矿热解过程的影响,得到了菱铁矿热解动力学模型及参数.实验结果表明,尾气中CO的最高峰值比CO2的最高峰值滞后510s.随温度升高,FeCO3热解速率单调增加,FeO的磁化速率在600650℃增速较快,于700℃附近出现最大值;随气氛中CO2含量增加,FeCO3热解速率单调下降,而FeO的磁化速率单调上升,两者的变化幅度逐步趋缓,至16%CO2时达最大.王家滩菱铁矿在悬浮状态下的热解机理为球体收缩模型R3,在热重实验中则表现为反应级数模型F1.

To analyze the influences of temperature and atmosphere on the siderite ore, isothermal decomposition experiments of siderite ore in the dilute phase suspension condition were conducted. The experimental results showed that the peak concentration of CO in the off-gas came out 5-10 s later than that of CO2, and the magnetization rate of FeO was sped up obviously between 600 and 650℃ and a maximum speed appeared at around 700℃. With the increase of concentration of COg in the atmosphere, the decomposition rate of siderite ore was reduced and the magnetization rate of FeO increased first, and then both showed a tendency to a limit at the concentration of 16% CO2. The shrinking sphere model with surface reaction rate controlling mechanism best fitted to the experiment data in the suspension condition while the reaction-order model F1 was best for that in the non-isothermal thermogravimetric analysis.