高炉炉缸渣铁焦物相界面及渣铁穿焦行为研究

The hearth activity of blast furnace (BF) is closely related to the dripping behavior of iron/slag through coke packed bed. The key to activate the BF hearth is to understand the mechanism of iron/slag dripping through coke packed bed, meanwhile effectively optimize the dripping process. However, the recent studies only concentrate on the behavior of the slag-iron-coke in the BF, which is quantitative and dependent on the industrial experience. The mechanism of slag-iron-coke interactions in the BF has not been studied and the underlying fundamentals are unclear. The present work first examine the phases of the deadman in the hearth based on the BF dissection and investigation. Next, the simulation of the actual working condition of the furnace will be performed in order to investigate the slag-coke and iron-coke reaction on the interface and understand the transport phenomenon/chemical reaction between iron and coke at different composition ranges. An experimental set-up of simulating the process of iron/slag dripping through coke packed bed will be further accomplished with the purpose of examining the effect of the coke properties, slag compositions on the holdup of the liquid slag/iron. The synergistic mechanism of the dripping process of slag/iron will be explored. Considering the synergistic effect of the physical transmission process and the interfacial chemical reaction of the slag/iron dripping process, a model of characterizing the index of slag/iron dripping process will be proposed and the potential of the effect of slag-iron-coke on the iron/slag dripping through coke packed bed will be clarified to provide scientific support and theoretical basis for activating the BF hearth.

高炉炉缸活性与高炉炉缸内渣铁穿焦的顺畅程度紧密相关。活跃高炉炉缸的关键在于明晰高炉炉缸内渣铁焦交互作用机制，同时有效调控渣铁穿焦过程。而目前对高炉炉缸内渣铁焦行为及炉缸活性的研究，仅停留在依靠生产经验而获得的表面认知，高炉炉缸活性基础理论研究相对薄弱。本项目首先基于高炉解剖及高炉破损调查研究，探明高炉炉缸中心料柱渣铁焦间物相组成及时空多尺度特征；然后模拟高炉炉缸实际工况，研究渣焦、铁焦界面化学反应，明晰不同渣铁组分及焦炭性状下渣铁焦间相际传输机制及化学反应机理；进一步建立模拟高炉渣铁从滴落到穿过料柱过程的实验装置，考察焦炭性状、渣相组分对炉渣滞留率及滴落速率的影响规律，继而探明渣铁同时穿焦过程中渣铁协同作用机制；兼顾渣铁穿焦过程的物理传输及界面化学反应的协同作用，提出渣铁穿焦能力指数模型，阐明高炉炉缸渣铁焦状态对高炉渣铁穿焦的作用潜力，为实现高炉炉缸活性的有效调控提供理论基础及技术支撑。

基于高炉解剖实地勘察，探明高炉炉缸渣铁焦间物相组成及时空多尺度特征；模拟高炉炉缸实际工况，研究渣铁焦界面化学反应，明晰不同渣铁组分及焦炭性状下渣铁焦间相际传输机制及化学反应机理；构建模拟高炉渣铁穿焦实验装置，考察渣相组分、焦炭性状等对渣铁在焦床中滞留率及滞留速率的影响规律，揭示渣铁同时穿焦过程协同作用机制；兼顾渣铁穿焦过程的物理传输及界面化学反应的协同作用，提出渣铁穿焦能力指数模型。得出主要结论如下：（1）高炉炉缸死料柱焦炭平均粒径为28.07mm，平均空隙度为0.56。径向方向焦炭粒径呈“M”型分布，焦炭孔隙率由铁口处的20.87%增加到炉底42.47%。高炉炉渣与焦炭的润湿性较差，炉渣与焦炭界面清晰，焦炭内部发达孔隙中填充富含Al2O3较高的渣相；铁焦界面存在“管状”、“树枝状”的FeO及Fe3Si，FeO中夹杂着少量的K、Na等有害元素。（2）渣焦和铁焦高温反应实验研究表明，渣焦界面可形成CA、CA2、CA6物相。反应层厚度随温度、时间、CaO含量的增加而增大。元素迁移过程中Ca离子和Si离子占主导。引入动力学模型进行回归，CA、CA2符合抛物线模型，界面反应是控速环节。提出并量化分析了焦炭与铁水的有效接触面积，证明焦炭中灰分是阻碍焦炭在铁水中溶解的主要原因。（3）自主设计并建立了模拟高炉渣铁穿焦的实验装置，考察了炉渣碱度、镁铝比、渣铁比、未燃煤粉含量、焦炭粒度等参数对滞留率及滞留速率的影响规律。渣相粘度、空隙率及渣铁焦润湿形成液桥是影响滞留率的主要因素。渣铁焦发生反应生成SiC改善界面润湿性是滞留率增大的重要原因。（4）基于流体力学原理，类比管束理论，构建了高炉炉缸渣铁穿焦指数模型。焦炭层空隙度对料层阻力影响最大。各因素的影响程度大小为：焦炭平均当量直径>形状因子>炉渣粘度（μ）=渣铁流速，权重比为2.2：1.7：1：1。（5）发表SCI论文15篇，EI论文1篇，中文核心期刊3篇，授权发明专利2项，参加国内外学术会议10次并作报告，获省部级二等奖1项，入选中国科协青年托举人才。