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研究了复合添加剂对赤铁矿球团性能的影响,并对其机理进行了探索。研究表明,适量的硼砂在低温下能生成一定量的液相,有助于球团焙烧过程中的固相反应,从而改善赤铁矿球团抗压强度,但过量的液相会阻碍晶粒的直接接触,不利于球团中Fe2O3再结晶,降低焙烧球强度;而且由于液相过多,还原过程粘结力减弱,恶化还原膨胀。MgO低温下稳定,阻碍了赤铁矿球团中Fe2O3的微结晶,降低预热球抗压强度,但高温下形成高强度、高熔点的铁酸镁系提高了焙烧球抗压强度且改善了还原膨胀。优化试验表明,0.2%硼砂和1.75%MgO所形成的复合添加剂能使得赤铁矿球团既有良好的冶金性能,又能满足球团生产的抗压强度要求。
The effects of composite additives on the properties of hematite pellets were studied and the mechanism was explored. The results show that the proper amount of borax can form a certain amount of liquid phase at low temperature, which is helpful to the solid phase reaction during the pellet roasting process, so as to improve the compressive strength of hematite pellets. However, excessive liquid phase will hinder the grain Of the direct contact is not conducive to the pellet recrystallization Fe2O3, reducing the firing ball strength; and because the liquid phase is too much, reducing the process of reducing cohesion, deterioration reduction and expansion. The stability of MgO at low temperature hindered the microcrystallization of Fe2O3 in hematite pellets and decreased the compressive strength of preheated ball. However, the formation of high strength and high melting point of magnesium ferrite at high temperature increased the compressive strength and improved the compressive strength Restore expansion. The optimization test shows that the composite additive of 0.2% borax and 1.75% MgO can make the hematite pellets not only have good metallurgical properties, but also meet the compressive strength requirements of pellet production.