| 高炉炉缸含钛保护层物相及TiC0.3N0.7形成机理 |
| |
| 引用本文： | 焦克新,张建良,刘征建,王广伟. 高炉炉缸含钛保护层物相及TiC0.3N0.7形成机理[J]. 工程科学学报, 2019, 41(2): 190-198. DOI: 10.13374/j.issn2095-9389.2019.02.005 |
| |
| 作者姓名： | 焦克新 张建良 刘征建 王广伟 |
| |
| 作者单位： | 北京科技大学冶金与生态工程学院, 北京 100083 |
| |
| 基金项目： | 国家青年自然科学基金资助项目51704019 |
| |
| 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TiC0.3N0.7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TiC0.3N0.7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, TiC0.3N0.7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 TiC0.3N0.7 析出温度 |
| 收稿时间： | 2018-02-28 |
Mineralogical phase and formation mechanism of titanium-bearing protective layers in a blast furnace hearth |
| |
| Affiliation: | School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, China |
| |
| 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 composition, formation mechanism, and ratio of C to N in the Ti(C, N) solid solution leaves the blast furnace operator unable to employ a scientific and effective measure to deal with abnormal hearth erosion. As a result, frequent hearth breakouts might occur, causing great financial 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 TiCxN1-x which formed in the blast furnace is TiC0.3N0.7. 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 different, i.e., more TiC at higher temperatures but more TiN at lower temperatures. At 1423℃, the TiC0.3N0.7 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, temperature, 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. |
| |
| Keywords: | |
|
| 点击此处可从《工程科学学报》浏览原始摘要信息 |
|
点击此处可从《工程科学学报》下载免费的PDF全文 |
|
