Abstract: The kish graphite separated from molten iron is a kind of sustainable resource. Because of the huge production of pig iron, this method of recovering kish graphite from molten iron has a broad prospect. In this work, the effects of blowing argon into the molten iron, different initial temperatures, and different cooling rates of molten iron on the precipitation behavior of kish graphite were investigated using scanning electron microscope, X-ray diffraction, and Raman techniques. The results showed that blowing argon into molten iron can effectively promote the floating and separation of kish graphite precipitated from molten iron. The initial temperature of molten iron had a significant effect on the amount and size of kish graphite precipitation, which mainly manifested that the higher the initial temperature, the flatter and smoother the surface of kish graphite, and the larger the size of precipitation, and the larger the amount of precipitation. The larger the cooling rate was, the less the amount of kish graphite precipitated and the smaller the kish graphite size was, and the kish graphite with a larger size can be obtained at a slower cooling rate. In addition, the precipitated kish graphite was used as lithium-ion anode material, which showed excellent cyclic stability and high specific capacity. In conclusion, kish graphite with different surface structures and sizes can be obtained by controlling the process conditions, which proved the feasibility of obtaining kish graphite by cooling molten iron. On this base, two new kish graphite production processes were proposed to provide a theoretical reference for the industrialization of kish graphite precipitated from molten iron.

Key words: molten iron, kish graphite, precipitation of carbon, blowing argon, negative electrode material

摘要： 铁水中析出的片状石墨是一种可持续利用的资源，由于我国生铁产量巨大，因此从铁水中回收石墨具有广阔的应用前景。本工作通过扫描电子显微镜(SEM)、X射线衍射(XRD)、拉曼光谱(Raman)等手段，研究了向铁水中吹氩、铁水初始温度和冷却速度等条件对片状石墨析出行为的影响。结果表明，向铁水中吹氩可以有效促进铁水中片状石墨的上浮与分离。铁水初始温度对石墨析出量和尺寸有显著影响，主要表现在初始温度越高，石墨表面越平整光滑、尺寸越大、析出量越多。此外冷却速度越大，石墨析出量越少，石墨尺寸越小，较慢的冷却速度可获取更大尺寸的石墨。析出的片状石墨作为锂离子电池负极材料表现出良好的循环稳定性和高比容量。综上，通过控制工艺条件可获得不同表面结构和尺寸的石墨，证明通过铁水降温获取石墨具有一定的可行性，据此提出了两种新的石墨生产工艺，可为铁水析出石墨的工业化提供理论参考。

关键词: 铁水, 片状石墨, 析碳, 吹氩, 负极材料