摘要
因为白云鄂博铁精矿球团含有较多的碱金属和氟,从而产生异常还原膨胀,而添加MgO可以有效抑制其还原膨胀,但是MgO的添加势必影响球团的矿相组成。目前研究多注重MgO、F、碱金属中某一单因素对球团物相的影响,而对3者共同作用于球团物相的影响还缺乏深入研究。采用正交试验的方法研究了(K_(2)O+Na_(2)O)、CaF_(2)和MgO对赤铁矿球团矿相组成的影响,并利用矿相显微镜、SEM-EDS、XRD并结合FactSage软件计算研究了它们在球团中的分布情况。研究结果表明,MgO对球团矿中含铁矿物和孔洞影响明显,对渣相量影响不大。MgO的添加降低了Fe_(2)O_(3)的开始分解温度,促进了赤铁矿分解为磁铁矿,焙烧过程中Mg^(2+)通过扩散进入到磁铁矿晶格中从而形成含镁磁铁矿并稳定了磁铁矿的结构,使得大部分MgO进入球团铁相,并随着MgO加入量的提高,含镁磁铁矿含量快速升高,导致球团中磁铁矿含量增加,提高了球团矿的稳定性,形成的磁铁矿多处于原赤铁矿基体的边缘部位并与赤铁矿互相连接在一起。当MgO添加量由1%提高到5%时,磁铁矿提高6.6%,赤铁矿降低15.4%,孔洞所占比例提高9.5%;添加的(K_(2)O+Na_(2)O)全部进入渣相,对球团渣相影响较大。当其添加量超过0.2%后,渣中Fe_(2)O_(3)溶解量快速升高,使得球团中液相量增加,而在随后的冷却过程中液相凝固导致球团体积收缩,引起球团孔隙率降低,当w(K_(2)O+Na_(2)O)由0.1%提高到0.4%时,球团渣相量提高2.6%,孔隙率降低5.9%,渣相大多分布于各铁氧化物之间,无固定的形状;CaF2全部进入渣相,对球团矿相组织影响较小。
Baiyun Obo ore pellets have abnormal reduction expansion due to the presence of more alkali metals and fluorine.The addition of MgO can effectively inhibit its reduction expansion and MgO is bound to affect the mineral phase composition of pellets.At present,more attention is paid no the influence of a single factor in magnesium oxide,fluorine and alkali metals on the phase of pellets,but the cooperated influence of the three factors on the phase of pellets is still lack of in-depth study.The effects of(K_(2)O+Na_(2)O),CaF_(2) and MgO on the mineral phase composition of the hematite pellets were studied by orthogonal test,and their distribution in the hematite pellets was studied by mineral phase microscope,SEM-EDS,XRD and FactSage software.The results show that MgO has a significant effect on iron-containing minerals and pores of pellets,but has little effect on slag phase.The addition of magnesium oxide reduces the initial decomposition temperature of Fe_(2)O_(3),and promotes the decomposition of hematite into magnetite.During the roasting process,Mg^(2+)diffuses into the magnetite lattice to form magnesium-containing magnetite and stabilizes the structure of magnetite,so that most of the magnesium oxide enters the iron phase of the pellets.With the increase of MgO,the content of magnesium-containing magnetite increases rapidly,which leads to the increase of magnetite content in the pellets and improves the stability of the pellets.The formed magnetite is mostly located at the edge of original hematite matrix and is connected with the hematite.When the content of MgO increased from 1% to 5%,the magnetite content increased by 6.6%,the hematite content decreased by 15.4%,and the proportion of pores increased by 9.5%.The addition of(K_(2)O+Na_(2)O)all entered into the slag phase,which had a great influence on the slag phase of pellets.When the addition content of(K_(2)O+Na_(2)O)exceeded 0.2%,the dissolution amount of Fe_(2)O_(3) in the slag increased rapidly,which made the amount of liquid phase in the pellet increased.In the subsequent cooling process,the solidification of liquid phase led to the volume shrinkage of pellet,resulting in a decrease in the porosity of pellet.When the content of(K_(2)O+Na_(2)O)increased from 0.1% to 0.4%,the content of slag phase increased by 2.6% and the porosity decreased by 5.9%.The slag phase was mostly distributed among iron oxides without fixed shape.All of CaF2 entered into the slag phase and had little effect on the mineral phase of pellets.
作者
王永斌
彭军
罗果萍
张芳
安胜利
WANG Yong-bin;PENG Jun;LUO Guo-ping;ZHANG Fang;AN Sheng-li(School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China;School of Material and Metallurgy,Inner Mongolia University of Science and Technology,Baotou 014010,Nei Mongol,China)
出处
《钢铁》
CAS
CSCD
北大核心
2022年第4期34-42,共9页
Iron and Steel
基金
国家自然科学基金资助项目(51664044,51864041)。
关键词
球团
矿相组织
氧化镁
氟
碱金属
pellet
mineral phase
MgO
fluorine
alkali metals
作者简介
王永斌(1973-),男,博士生,讲师,E-mail:btwyb0313@163.com;通讯作者:安胜利(1961),男,博士,教授,E-mail:san@imust.edu.cn。
