机构地区:[1]内蒙古科技大学材料与冶金学院,内蒙古包头014000
出 处:《中国冶金》2024年第3期47-55,共9页China Metallurgy
基 金:国家自然科学基金项目资助项目(51904161);内蒙古自治区高等学校青年科技英才支持计划资助项目(NJYT22060);内蒙古自治区直属高校基本科研业务费项目(2022QNJS011)。
摘 要:天然块矿具有品位高、粒度适宜、组织结构疏松、气孔度较高等特点,应用于高炉炼铁在性能上具有一定的优势。但天然块矿湿度大、结晶水含量高、表面附着细小颗粒等问题成为阻碍块矿大规模入炉的关键,而通过高温预处理可以有效降低天然块矿内部结晶水含量,提高孔隙率。为此探索高温预处理前后褐铁矿的冶金性能,判断高温预处理后天然褐铁矿入炉的可行性。研究证明高温预处理使得褐铁矿内部结构发生改变,由紧实的致密状结构转变为贯通状板结结构,结晶水含量降低,孔隙率提高,抗压强度降低。低温还原粉化指数(I_(RD))和还原度(R_(t))是评价矿石原料入炉的重要指标,是块矿能否顺利入炉、保障高炉透气性和高炉顺行的评判依据。高温预处理对天然褐铁矿冶金性能具有有利影响,低温还原粉化过程主要降低小颗粒褐铁矿掉落比例,高温预处理后褐铁矿I_(RD>6.30)由66.12%提高至73.21%,I_(RD>3.15)由82.08%提高至86.48%,I_(RD<0.50)由7.97%降低至6.47%;高温预处理主要影响褐铁矿中温还原过程中还原性气体与褐铁矿接触面积,即孔隙率是影响还原度的因素之一,经高温预处理后褐铁矿平均孔隙率提高4.77个百分点,高温预处理前褐铁矿R_(t)由79.58%提高到84.23%。研究结果可为高温预处理后褐铁矿入炉提供理论依据。Natural lump ore has the characteristics of high grade, suitable particle size, loose structure and high porosity.It has certain advantages in the performance when used in the blast furnace.However, the problems of high humidity, high crystal water content and fine particles attached to the surface of natural lump ore have become the key to hinder the large-scale entry of lump ore into the furnace.High temperature pretreatment can effectively reduce the internal crystal water content of natural lump ore and improve the porosity.Based on this, the metallurgical properties of limonite before and after high temperature pretreatment was explored, and the feasibility of natural limonite into the furnace after high temperature pretreatment was judged.It is proved that the internal structure of limonite is changed by high temperature pretreatment, from compact dense structure to through-like plate structure, the content of crystal water is reduced, the porosity is increased, and the compressive strength is reduced.Low temperature reduction disintegration index(I_(RD))and reduction degree(R_(t))are important indicators for evaluating the standard of ore raw materials into the furnace, and are the basis for judging whether the lump ore can be smoothly fed into the furnace, ensuring the permeability of the blast furnace and the smooth running of the blast furnace.High temperature pretreatment of natural limonite has a beneficial effect on its metallurgical properties.The proportion of small particle limonite falling is mainly reduced during the low temperature reduction disintegration process.After high temperature pretreatment, I_(RD>6.30) of limonite increases from 66.12% to 73.21%,I_(RD>3.15) increases from 82.08% to 86.48%,and I_(RD<0.50) decreases from 7.97% to 6.47%. High temperature pretreatment mainly affects the contact area between reducing gas and limonite in the process of medium temperature reduction of limonite, that is, porosity is one of the factors affecting the reduction degree.After high temperature pret
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