活性石灰与CaO-SiO_(2)-Fe_(t)O熔渣间界面结构特性  

Characterization of interfacial structure between quicklime and CaO-SiO_(2)-Fe_(t)O slag

作　　者：张梦旭 李建立[1,2] 李山南 余岳[1,2] 谢潇 ZHANG Meng-xu;LI Jian-li;LI Shan-nan;YU Yue;XIE Xiao(Key Laboratory of Iron and Steel Metallurgy and Resource Utilization,Ministry of Education,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;Hubei Key Laboratory of New Processes of Iron and Steel Metallurgy,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China;School of Computer Science and Technology,Wuhan University of Science and Technology,Wuhan 430081,Hubei,China)

机构地区：[1]武汉科技大学钢铁冶金及资源利用省部共建教育部重点实验室,湖北武汉430081 [2]武汉科技大学钢铁冶金新工艺湖北省重点实验室,湖北武汉430081 [3]武汉科技大学计算机科学与技术学院,湖北武汉430081

出　　处：《钢铁》2023年第3期53-60,共8页Iron and Steel

基　　金：国家自然科学基金资助项目(51974210,52074197);湖北省自然科学基金资助项目(2019CFB697)。

摘　　要：2020年,中国的粗钢产量为10.65亿t,钢渣产量占比为10%~15%。钢渣中存在10%~20%的f-CaO会使钢渣消化而引起体积不稳定,这是钢渣综合利用的主要障碍之一。而f-CaO的产生与转炉吹炼过程中活性石灰的溶解情况紧密相关。基于实验室制备合成渣和活性石灰,采用X射线衍射仪、场发射扫描电子显微镜及其配置的能谱仪等方法,对转炉钙质成渣工艺条件下活性石灰颗粒与熔渣间的界面结构演变行为展开研究。结果表明,在转炉不同冶炼时期活性石灰与熔渣间的反应界面结构发生改变。在初期,反应界面由5个不同的区域组成,分别为未溶解的石灰层、CaO-FeO固溶体层、(Ca, Mg, Fe)橄榄石层及熔渣本体;随着反应进行,熔渣碱度提升,不连续的2CaO·SiO_(2)层开始在CaO-FeO固溶体层和(Ca, Mg, Fe)橄榄石层间形成,同时CaO-FeO固溶体层和(Ca, Mg, Fe)橄榄石层厚度不断减小。CaO-FeO固溶体层由约15μm减小至约5μm,(Ca, Mg, Fe)橄榄石层由约55μm减小至约15μm。由于反应界面形成了FeO和CaO两种浓度差,促使反应不断进行。反应进行到FeO质量分数小于20%时,CaO会与(Ca, Mg, Fe)橄榄石发生反应生成C_(2)S(2CaO·SiO_(2)),因此在熔渣A4中出现了约3μm厚但并不连续的C_(2)S层。随着反应时间的延长,石灰颗粒将会被熔渣中形成的连续C_(2)S层包围,而高熔点且连续致密的C_(2)S层将阻碍石灰与熔渣进行传质,反应的传质环节受限,反应的进一步进行受阻。In 2020,China′s crude steel production is 1.065billion tons,and the proportion of steel slag production is 10%-15%.The presence of 10%-20%f-CaO in steel slag will cause volumetric instability due to slag digestion,which is one of the main obstacles to the comprehensive utilization of steel slag.The generation of f-CaO is closely related to the dissolution of quicklime in the converter blowing process.Based on the laboratory preparation of syn-thetic slag and quicklime,the structural evolution behavior of the interface between quicklime particles and slag under the conditions of converter calcium slagging process was investigated by X-ray diffractometer,field emission scanning electron microscope and its configured energy spectrometer.The results show that the structure of the reaction in-terface between quicklime and slag changes during different smelting periods in the converter.In the early stage,the reaction interface consists of five different regions,namely the undissolved lime layer,CaO-FeO solid solution layer,(Ca,Mg,Fe)olivine layer and the slag body,as the reaction proceeds and the alkalinity of the slag increases,discon-tinuous 2CaO-SiO_(2)layers start to form between the CaO-FeO solid solution layer and the(Ca,Mg,Fe)olivine layer,while the thickness of CaO-FeO solid solution layer and(Ca,Mg,Fe)olivine layer decreased continuously from about 15μm to about 5μm and(Ca,Mg,Fe)olivine layer decreased from about 55μm to about 15μm.The reaction pro-ceeded continuously because of the difference in concentration between FeO and CaO at the reaction interface.The reaction proceeds until the mass fraction of FeO is less than 20%,CaO reacts with(Ca,Mg,Fe)olivine to form C_(2)S(2CaO·SiO_(2)),so that an approximately 3μm thick but discontinuous C_(2)S layer appears in the slag A4.As the re-action time increases,the lime particles will be surrounded by a continuous C_(2)S layer in the slag.The high melting point and continuous dense C_(2)S layer will prevent the mass transfer between lime and slag,and the mass

关 键 词：活性石灰 反应界面 2CaO·SiO_(2) 溶解 传质 

分 类 号：TF703[冶金工程—钢铁冶金]