Guo Ziyu, Jiao Kexin, Zhang Jianliang, Ma Hengbao, Meng Sai, Wang Zhongyi, Zhang Jian, Zong Yanbing
School of Metallurgical and Ecological Engineering, University of Science and Technology Beijing, Beijing 100083, P. R. China.
State Key Laboratory of Advanced Metallurgy, University of Science and Technology Beijing, Beijing 100083, P. R. China.
ACS Omega. 2021 Sep 23;6(39):25430-25439. doi: 10.1021/acsomega.1c03398. eCollection 2021 Oct 5.
The graphitization and performance of deadman coke in the blast furnace hearth have an essential influence on the longevity of the blast furnace. In this paper, coke samples were obtained from various heights in a hearth during the overhaul of the blast furnace. The voidage, particle size, graphitization degree, microstructure, and structure evolution of multiple cokes were analyzed through digital image processing, XRD, Raman spectra, scanning electron microscopy, and energy-dispersive X-ray spectroscopy (SEM-EDS). The graphitization results were compared with feed coke, tuyere coke, cohesive zone coke, and deadman coke in reference, and the main findings were analyzed. The following results were obtained. First, the voidage of deadman coke increased and then decreased with the increase of the depth while the particle size continued to decrease. In addition, the consumption rate of coke as a carburizer, reductant, and heart source was 8.47, 30.95, and 60.58%, respectively. Second, the graphitization degree of deadman coke was extremely high and showed a trend of first increasing and then decreasing. Finally, the evolution mechanism of coke graphitization was proposed. Molten iron, alkali metal, temperature, and mineral were the crucial factors that affect the graphitization of coke. The turning point of the graphitization degree was related to the buoyancy of the hearth.
高炉炉缸中半焦的石墨化及其性能对高炉寿命有着至关重要的影响。本文在高炉大修期间从炉缸不同高度获取了焦炭样品。通过数字图像处理、XRD、拉曼光谱、扫描电子显微镜和能量色散X射线光谱（SEM - EDS）对多种焦炭的空隙率、粒度、石墨化程度、微观结构及结构演变进行了分析。将石墨化结果与参考的入炉焦炭、风口焦炭、软熔带焦炭及半焦进行了比较，并对主要发现进行了分析。得到以下结果。其一，半焦的空隙率随深度增加先增大后减小，而粒度持续减小。此外，焦炭作为渗碳剂、还原剂和热源的消耗率分别为8.47%、30.95%和60.58%。其二，半焦的石墨化程度极高，呈先升高后降低的趋势。最后，提出了焦炭石墨化的演变机制。铁水、碱金属、温度和矿物质是影响焦炭石墨化的关键因素。石墨化程度的转折点与炉缸浮力有关。
