低硅含镁球团矿抗压强度及冶金性能

提高入炉原料品位降低硅含量,改善冶金性能是高炉精料的主要方向。研究了低硅球团矿的还原膨胀率及MgO对低硅球团矿抗压强度和冶金性能的影响。研究结果显示,低硅球团矿虽然具有品位高,脉石含量低等优点,但随着SiO2含量的降低球团矿还原膨胀率恶化,影响高炉冶炼。低硅球团配加含镁添加剂可以有效控制还原膨胀率,同时改善球团矿的还原度和熔滴性能。球团矿SiO2的质量分数低于2%时,还原膨胀率在60%以上;当MgO的质量分数提高到2.15%以上时,还原膨胀率能降到20%以下,但随着MgO含量的增加低硅球团矿抗压强度下降,需要提高焙烧温度,才能形成稳定的铁酸镁,改善抗压强度。MgO的质量分数为2.15%时,焙烧温度要提高到1 270℃,MgO的质量分数超过2.8%以上时,焙烧温度需要提高到1 300℃。

Compressive Strength and Metallurgical Property of Low Silicon Magnesium Pellet

Increasing iron grade, lowering silicon content and improving metallurgical property was the main direction of blast furnace beneficiated burden. The reduction swelling index and effect of MgO content on compressive strength and metallurgical performance of low silicon pellet were studied. The results show that, low silicon pellet has high iron grade and low gangue, however the reduction swelling index will deteriorate with decrease of silicon content which influence blast furnace operation. The reduction swelling index of low silicon pellet can be improved by increasing of MgO content, and reducibility and smelting performance also can be improved at the same time. While SiO2 content is lower than 2%, the reduction swelling index is higher than 60% and it can be lowered to less than 20% after MgO content is increased to 215%. The compressive strength of low silicon pellet will decrease with increase of MgO content, however higher firing temperature can form stable and uniform magnesium ferrite which is useful to increase the compressive strength of low silicon magnesium pellet. The firing temperature should be increased to 1270℃, while MgO content is 215%, and 1300℃ of temperature is needed for pellet contains 28% MgO.