摘要
包钢巴润矿具有粒度细、品位高、价格低廉、适合球团生产等特点,但该矿是一种典型的高碱负荷磁铁矿,其中碱金属含量较高。以揭示含钾脉石对铁氧化物还原膨胀性的影响为出发点,采用分阶段还原法,通过在线检测的方法研究了不同天然钾长石添加量对CO的Fe2O3→Fe3O4,Fe3O4→FeO以及FeO→Fe分阶段还原过程试样的线膨胀率进行了检测,并对各阶段还原产物的物相组成和显微结构采用XRD和SEM进行了分析。结果表明,试样在氧化焙烧过程中,天然钾长石中的钾长石熔化后形成玻璃相,SiO2以石英的形式析出。试样中天然钾长石质量分数从0增加到12%,在Fe2O3→Fe3O4还原阶段,其线性膨胀率从2.19%下降到2.11%,试样在焙烧过程中钾长石形成的渣相对Fe2O3还原膨胀性起到抑制作用;在Fe3O4→FeO还原阶段,其线性膨胀率从-0.51%增加到0.46%,钾长石引起Fe3O4晶格畸变,造成Fe3O4还原膨胀加剧;在FeO→Fe还原阶段,其线性膨胀率从-6.26%增加到-1.68%,天然钾长石中的SiO2与FeO结合形成铁橄榄石对FeO还原过程的铁相收缩起到抑制作用。因此,钾长石主要对CO还原Fe2O3的第Ⅰ和第Ⅱ阶段作用明显,SiO2主要对还原第Ⅲ阶段产生影响。
Baren iron ore concentrate of Baotou Steel has the properties of fine granularity,high grade,low cost and suitable for pellet production,but the ore concentrate is a kind of typical magnetite containing alkali metal elements such as potassium and sodium.In order to reveal the effect of potassium gangue on the swelling behavior of iron oxide,the segmented reduction of Fe2O3 was adopted with on-line inspection to study the impact of the different natural potassium feldspar content on the linear expansion during the reduction process of Fe2O3→Fe3O4,Fe3O4→FeO and FeO→Fe respectively by CO gas.At the same time,the mineral phases and microstructures of the reduction products of each reduction stage were analyzed by XRD and SEM.The results show that the potassium feldspar in the natural potassium feldspar melts to form the glass phase and SiO2 precipitates in the form of quartz during the process of oxidizing roasting.With the increase of the content of natural potassium feldspar in the samples from 0 to 12 mass%,the linear expansion rate decreases from 2.19%to 2.11%in the reduction stage of Fe2O3→Fe3O4 due to the effect of the slag phase from potassium feldspar which is able to reduce Fe2O3 content.In the Fe3O4→FeO reduction stage,potassium feldspar destories Fe3O4 lattice,which causes the reduction and expansion of Fe3O4 to rise,then the linear expansion rate increases from-0.51%to 0.46%.In the reduction stage of FeO→Fe,the linear expansion rate increases from-6.26%to-1.68%,because the combination of SiO2 and FeO in natural potash feldspar to form iron olivine can restrain the iron phase shrinkage of FeO reduction process.The natural potassium feldspar displays different effect on linear expansion ratio of iron oxides in the different reduction stages.Therefore,potassium feldspar mainly has a significant effect on the reduction of Fe2O3 by CO in the first stage and the second stage,and SiO2 in the nature potassium feldsparmainly affects the third reduction stage.
作者
张芳
聂东娥
霍明鹤
王艺慈
罗果萍
ZHANG Fang;NIE Dong-e;HUO Ming-he;WANG Yi-ci;LUO Guo-ping(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Nei Mongol,China)
出处
《钢铁研究学报》
CAS
CSCD
北大核心
2020年第11期958-967,共10页
Journal of Iron and Steel Research
基金
国家自然科学基金资助项目(51664044,51864041)
内蒙古自然科学基金资助项目(2018LH05005)。
关键词
钾长石
铁氧化物
CO
还原膨胀性
potassium feldspar
iron oxide
CO
swelling behavior
