摘要
球团抗压强度是衡量球团能否进入高炉冶炼的主要指标之一,球团抗压强度取决于球团矿物组成及微观结构。以中关铁矿为基础造球原料,通过内配钙、镁添加剂制备低硅熔剂性球团矿。通过系统研究不同MgO含量、碱度及SiO_(2)含量时球团微观结构及矿物分布形态,揭示低硅熔剂性球团抗压强度的变化规律。研究结果表明,提高焙烧温度和碱度可有效提高球团抗压强度;在SiO_(2)含量较低时,球团矿主要靠赤铁矿连晶固结,强度变化并不明显;SiO_(2)质量分数升高至3.5%和4.0%时,赤铁矿结晶逐渐互联成片,连晶逐渐变得粗大且紧密,结构力较强,球团抗压强度提高。随着碱度的提高,赤铁矿再结晶较好,单独颗粒状少并且结晶互联成块状,磁铁矿减少,低硅熔剂性球团在焙烧过程中液相量增加,出现铁酸钙体系液相使球团强度提高;随着MgO含量的提高,更多的Mg^(2+)进入磁铁矿相,弥补了晶格缺陷,铁酸镁含量升高并呈现针状或片状分布在赤铁矿中,抑制了焙烧过程中液相生成,在冷却过程中使得球团矿内部的气孔变小从而提升球团致密度,增强球团强度。MgO含量继续增加,磁铁矿、玻璃相含量增加,赤铁矿和铁酸钙量相对减少;又因为Fe_(3)O_(4)的增多会使Fe_(2)O_(3)的连晶性能降低,最终导致球团抗压强度的降低。为探究低硅镁质熔剂性球团提供了理论指导和参考依据。
The compressive strength of the pellets is one of the main indicators to measure whether the pellets can enter the blast furnace smelting,and the compressive strength of the pellets is determined by the mineral composition and microstructure of the pellet.Zhongguan iron ore is used as the basic pelletizing raw material,and low-silica flux pellets are prepared by calcium and magnesium additives.By systematically studying the microstructure and mineral distribution morphology of pellets under different MgO content,alkalinity and SiO_(2)content,the change law of compressive strength of low silicon flux pellets was revealed.The results show that increasing the roasting temperature and alkalinity can effectively improve the compressive strength of pellets.When the SiO_(2)content was low,the pellets are mainly consolidated by hematite crystals,and the strength change is not obvious.When the mass percent of SiO_(2)increased to 3.5%and 4.0%,respectively,the hematite crystals were gradually interconnected into pieces,and the crystals gradually became coarse and compact,the structural strength was strong,and the compressive strength of the pellets increased.With the increase of alkalinity,hematite recrystallization is better,there are few granular alone and the crystals are interconnected into blocks,magnetite is reduced,the liquid phase of low silicon flux pellets increases during the roasting process,and the liquid phase of calcium ferrite system appears to increase the strength of the pellets.With the increase of MgO percentage,more Mg2+entered the magnetite phase,which made up for the lattice defect,and the magnesium ferrite content increased and appeared needle-like or flake distribution in hematite,which inhibited the formation of liquid phase during the roasting process,and made the pores inside the pellet smaller during the cooling process,thereby improving the density of the pellet and enhancing the strength of the pellet.The content of MgO continued to increase,the content of magnetite and glass phase increased,a
作者
倪杰
师学峰
白晨晨
张玉柱
刘连继
肖洪
NI Jie;SHI Xuefeng;BAI Chenchen;ZHANG Yuzhu;LIU Lianji;XIAO Hong(School of Metallurgy and Energy,North China University of Technology,Tangshan 063210,Hebei,China;Office of the Chief Engineer,Tangshan Iron and Steel Group Co.,Ltd.,Tangshan 063011,Hebei,China)
出处
《钢铁》
CAS
CSCD
北大核心
2024年第2期36-43,共8页
Iron and Steel
基金
河北省高等学校科学技术研究资助项目(ZD2020116)。
关键词
熔剂性球团矿
低硅精粉
抗压强度
矿物组成
微观结构
flux based pellets
low silicon refined powder
compressive strength
mineral composition
microstructure
