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.

中文翻译：

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Deadman 焦炭在大型解剖高炉中的石墨化和性能

高炉炉缸中死焦的石墨化和性能对高炉的寿命有重要影响。在本文中，焦炭样品是在高炉大修期间从炉膛中的不同高度获取的。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）分析了多种焦炭的空隙率、粒径、石墨化程度、微观结构和结构演变。将石墨化结果与原料焦、风口焦、粘结区焦、死区焦作对比，分析了主要发现。获得了以下结果。首先，死焦的空隙率随着深度的增加而增加然后减少，而粒径则继续减小。此外，作为增碳剂、还原剂和心源的焦炭消耗率分别为8.47、30.95和60.58%。二是死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化机理。铁水、碱金属、温度和矿物是影响焦炭石墨化的关键因素。石墨化程度的转折点与炉膛的浮力有关。提出了焦炭石墨化的演化机理。铁水、碱金属、温度和矿物是影响焦炭石墨化的关键因素。石墨化程度的转折点与炉膛的浮力有关。提出了焦炭石墨化的演化机理。铁水、碱金属、温度和矿物是影响焦炭石墨化的关键因素。石墨化程度的转折点与炉膛的浮力有关。