2种气氛下铁矿石粉煤基直接还原的热重研究

Thermogravimetric study of iron ore powder coal-based direct reduction in two atmosphere

采用热重分析仪对大同煤、神木煤以及阳泉煤分别与铁矿石粉的混合物进行了氮气和二氧化碳2种气氛下的非等温质量损失特性的对比实验研究。研究结果表明:二氧化碳气氛下3个煤种分别同铁矿石粉混合物的反应阶段均为扩散控速,其中大同烟煤-铁矿石粉混合物的反应起始温度较低,阳泉无烟煤-铁矿石粉混合物的反应温度范围较大,反应的起始温度、反应温度范围以及表观活化能参数均由煤种的气化特性决定;反应气氛对混合物中煤的挥发分析出过程无显著影响;二氧化碳气氛下的反应阶段对应氮气气氛下的第1个反应阶段,且在这个反应阶段中,碳的气化反应同铁氧化物的还原反应相互抑制。

The nonisothermal comparative experimental study on mass loss of Datong bituminite,Shenmu lignite and Yangquan anthracite with iron ore powder was performed in N2 or CO2 atmosphere by thermogravimetric analyzer.The results show that the controlled steps of reaction rate in the three coal-ore mixtures are diffusion in CO2 atmosphere,in which the started temperature of Datong bituminite-iron ore mixture is lower and the temperature range of Yangquan anthracite-iron ore is higher.Furthermore,the reaction parameters like started temperature,temperature range and apparent activation energy are controlled by the carbon gasification.The comparison of the two atmosphere shows that the volatilization process of coal in the mixture is not obviously affected by the atmosphere.The reaction stage in CO2 atmosphere corresponds to the first reaction stage in N2 atmosphere,and the carbon gasification and the iron oxide reduction are mutually restricted.