焙烧温度对熔剂性球团性能及微观结构的影响

Effect of firing temperature on properties and microstructure of fluxed pellets

为掌握焙烧温度对熔剂性球团性能的影响,本文依托624 m~2带式焙烧机分别对1 225℃和1 255℃两种焙烧温度下的球团性能进行研究。结果表明:当焙烧温度由1 225℃提高至1 255℃时,球团抗压强度由2 504 N/P提高至3 653 N/P,1 h还原度由70.0%下降至60.2%,还原膨胀指数由10.7%降低至9.1%,低温还原粉化性能RDI由79.7%降低至60.5%,RDI由90.8%降低至84.9%,RDI变化不大;球团真密度略有提高,视密度明显提高(由3.69 g/cm^(3)提高至3.90 g/cm^(3)),总气孔率由23.20%下降至18.86%。因此,生产过程中通过调整合适的焙烧温度,控制适宜的液相量,有利于赤铁矿的再结晶和液相的均匀分布,从而改善熔剂性球团性能。

In order to know the effect of firing temperature on the properties of fluxed pellets, two firing temperatures of 1 225 ℃ and 1 255 ℃ were studied by 624 m~2 travelling grate machine.The results showed that with the increase of firing temperature from 1 225 ℃ to 1 255 ℃,the compressive strength of pellets increased from 2 504 N/P to 3 653 N/P,the 1 h reduction degree decreased from 70% to 60.2%,the reduction swelling index decreased from 10.7% to 9.1%,the RDIdecreased from 79.7% to 60.5%,RDIdecreased from 90.8% to 84.9%,and RDIchanged little, the true density of pellets increased slightly, the apparent density increased significantly from 3.69 g/cm^(3) to 3.9 g/cm^(3),and the total porosity decreased from 23.2% to 18.86%.By adjusting the appropriate firing temperature and controlling the appropriate amount of liquid phase, it is conducive to the recrystallization of hematite and the uniform distribution of liquid phase, so as to improve the properties of fluxed pellets.