工程科学学报，第41卷，第2期：190-198,2019年2月 Chinese Journal of Engineering,Vol.41,No.2:190-198,February 2019 DOI:10.13374/j.issn2095-9389.2019.02.005;http://journals.ustb.edu.cn 高炉炉缸含钛保护层物相及TC3N。7形成机理 焦克新✉，张建良，刘征建，王广伟 北京科技大学冶金与生态工程学院，北京100083 ✉通信作者，E-mail:jiaokexin_ustb@126.com 摘要，基于高炉破损调查取样分析，借助X射线荧光分析、X射线衍射分析、电子探针分析、扫描电子显微镜结合能谱分析 等手段分析了高炉炉缸、炉底不同部位形成的含钛保护层化学成分、物相组成和微观形貌，并建立正规溶液热力学模型对 (C,N)形成的热力学条件进行分析，然后针对高炉的实际工况，明晰高炉炉缸TCN。,形成的条件.结果表明，高炉炉缸侧 壁最薄处炭砖残余厚度仅为200mm;炉缸炉底炭砖表面普遍存在含钛保护层，保护层平均厚度在300~600mm左右，高炉炉 缸不同部位形成的保护层中Ti(C,N)主要以TiCa3N。,形式存在，并与Fe相聚集在一起.Ti(C,N)固溶体实际混合摩尔生成 吉布斯自由能显著低于标准混合摩尔生成吉布斯自由能和理想混合摩尔生成吉布斯自由能.在不同温度条件下，TC和TN 在固溶体中存在的比例不同，高温时以析出TiC为主，低温时以析出TN为主.Ti(C,N)固溶体的形成与高炉热力学状态条 件直接相关，TiC3N。.,在该高炉炉缸中的形成温度为1423℃. 关键词高炉；炉缸；含钛保护层；物相组成；TCN。7;析出温度 分类号TF533.2 Mineralogical phase and formation mechanism of titanium-bearing protective layers in a blast furnace hearth JIAO Ke-xin,ZHANG Jian-liang,LIU Zheng-jian,WANG Guang-wei School of Metallurgical and Ecological Engineering,University of Science and Technology Beijing,Beijing 100083,China ☒Corresponding author,E-mail:jiaokexin_usth@126.com ABSTRACT In theory and practice,TiO2-bearing iron ores are the preferred raw materials for prolonging blast furnace times due to their protection of the refractory lining of the hearth.Currently,however,a lack of detailed understanding of the mineralogical composi- tion,formation mechanism,and ratio of C to N in the Ti(C,N)solid solution leaves the blast furnace operator unable to employ a sci- entific and effective measure to deal with abnormal hearth erosion.As a result,frequent hearth breakouts might occur,causing great fi- nancial loss to steel companies.In the present work,in an attempt to clarify the essence of longevity blast furnaces,investigations were conducted into blast furnace hearth damage together with dissection analyses,to derive the mineralogical composition and microstructure of titanium-bearing protective layers.The results show that the exact chemical composition of the TiC,N,-which formed in the blast furnace is TiC.3 N.7.Based on thermodynamic analysis,the standard Gibbs free energy of the formation of Ti(C,N)decreases at first,then increases with increasing TiC content.At different temperatures,the proportion of TiC and TiN in the solid solution is differ- ent,i.e.,more TiC at higher temperatures but more TiN at lower temperatures.Atl423℃，the TiCo3N.,is formed in the hot-side of the investigated blast furnace hearth,and the thickness of the titanium-bearing protective layer varies with smelting intensity,tempera- ture,and circulation strength of hot metal.This paper classifies the protective layer into various types based on formation mechanism. Finally,a comprehensive regulatory scheme is presented to act as a basis for extending the lifespan of the blast furnace hearth. KEY WORDS blast furnace;hearth;titanium-bearing protective layer;phase composition;TiCo.3 No.;precipitation temperature 收稿日期：2018-02-28 基金项目：国家青年自然科学基金资助项目(51704019)工程科学学报,第 41 卷,第 2 期:190鄄鄄198,2019 年 2 月 Chinese Journal of Engineering, Vol. 41, No. 2: 190鄄鄄198, February 2019 DOI: 10. 13374 / j. issn2095鄄鄄9389. 2019. 02. 005; http: / / journals. ustb. edu. cn 高炉炉缸含钛保护层物相及 TiC0郾 3 N0郾 7 形成机理 焦克新苣 , 张建良, 刘征建, 王广伟 北京科技大学冶金与生态工程学院, 北京 100083 苣通信作者, E鄄mail: jiaokexin_ustb@ 126. com 摘 要 基于高炉破损调查取样分析,借助 X 射线荧光分析、X 射线衍射分析、电子探针分析、扫描电子显微镜结合能谱分析 等手段分析了高炉炉缸、炉底不同部位形成的含钛保护层化学成分、物相组成和微观形貌,并建立正规溶液热力学模型对 Ti (C, N)形成的热力学条件进行分析,然后针对高炉的实际工况,明晰高炉炉缸 TiC0郾 3N0郾 7形成的条件. 结果表明,高炉炉缸侧 壁最薄处炭砖残余厚度仅为 200 mm;炉缸炉底炭砖表面普遍存在含钛保护层,保护层平均厚度在 300 ~ 600 mm 左右,高炉炉 缸不同部位形成的保护层中 Ti(C, N)主要以 TiC0郾 3N0郾 7形式存在,并与 Fe 相聚集在一起. Ti(C, N)固溶体实际混合摩尔生成 吉布斯自由能显著低于标准混合摩尔生成吉布斯自由能和理想混合摩尔生成吉布斯自由能. 在不同温度条件下,TiC 和 TiN 在固溶体中存在的比例不同,高温时以析出 TiC 为主,低温时以析出 TiN 为主. Ti(C, N)固溶体的形成与高炉热力学状态条 件直接相关,TiC0郾 3N0郾 7在该高炉炉缸中的形成温度为 1423 益 . 关键词 高炉; 炉缸; 含钛保护层; 物相组成; TiC0郾 3N0郾 7 ; 析出温度 分类号 TF533郾 2 收稿日期: 2018鄄鄄02鄄鄄28 基金项目: 国家青年自然科学基金资助项目(51704019) Mineralogical phase and formation mechanism of titanium鄄bearing protective layers in a blast furnace hearth JIAO Ke鄄xin 苣 , ZHANG Jian鄄liang, LIU Zheng鄄jian, WANG Guang鄄wei School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China 苣Corresponding author, E鄄mail: jiaokexin_ustb@ 126. com ABSTRACT In theory and practice, TiO2 鄄bearing iron ores are the preferred raw materials for prolonging blast furnace times due to their protection of the refractory lining of the hearth. Currently, however, a lack of detailed understanding of the mineralogical composi鄄 tion, formation mechanism, and ratio of C to N in the Ti(C, N) solid solution leaves the blast furnace operator unable to employ a sci鄄 entific and effective measure to deal with abnormal hearth erosion. As a result, frequent hearth breakouts might occur, causing great fi鄄 nancial loss to steel companies. In the present work, in an attempt to clarify the essence of longevity blast furnaces, investigations were conducted into blast furnace hearth damage together with dissection analyses, to derive the mineralogical composition and microstructure of titanium鄄bearing protective layers. The results show that the exact chemical composition of the TiCxN1 - x which formed in the blast furnace is TiC0郾 3N0郾 7 . Based on thermodynamic analysis, the standard Gibbs free energy of the formation of Ti(C, N) decreases at first, then increases with increasing TiC content. At different temperatures, the proportion of TiC and TiN in the solid solution is differ鄄 ent, i. e. , more TiC at higher temperatures but more TiN at lower temperatures. At 1423 益 , the TiC0郾 3N0郾 7 is formed in the hot鄄side of the investigated blast furnace hearth, and the thickness of the titanium鄄bearing protective layer varies with smelting intensity, tempera鄄 ture, and circulation strength of hot metal. This paper classifies the protective layer into various types based on formation mechanism. Finally, a comprehensive regulatory scheme is presented to act as a basis for extending the lifespan of the blast furnace hearth. KEY WORDS blast furnace; hearth; titanium鄄bearing protective layer; phase composition; TiC0郾 3N0郾 7 ; precipitation temperature