某4000 m³级高炉炭砖侵蚀机理研究
A Study on the Erosion Mechanism of Carbon Bricks in a 4000 m³ Blast Furnace

大型高炉长寿化是实现炼铁工艺节能、减排、平衡成本与高产量的重要手段，而影响高炉寿命最重要的因素则是高炉炉缸炭砖的破损情况。本文对我国某4000 m³高炉炉缸炭砖的侵蚀行为进行了详细的分析，研究了炭砖的化学成分和物理性能的变化，讨论了残余炭砖热面的微观结构组成，得出了炉缸炭砖的侵蚀机理。结果表明，该4000 m³高炉炉缸炭砖的侵蚀在高度和圆周方向上较不均匀，在高度方向上，出铁口中心线以下2.1 m处的炭砖最为严重，圆周方向侵蚀最严重处则主要发生在铁口正下方与靠近铁口周围区域，炉缸侵蚀形貌整体“象脚形”。使用近15年后的高炉炭砖耐压强度大大降低，灰分含量明显增加，炭砖热面处富集有大量氧化锌与氧化钾及氧化钠。在炉缸炭砖砖缝间和炭砖脆化层内部发现有大量的锌沉积，有效证明了锌蒸气通过在炭砖表面的沉积和渗入是促进炭砖脆性层形成、降低炭砖抗铁水侵蚀能力、增加炉缸炭砖破裂的风险的重要原因。
The prolonged operation of large-scale blast furnaces is an important means to achieve energy saving, emission reduction, cost balance, and high productivity in ironmaking processes. The most critical factor affecting the lifespan of a blast furnace is the damage to the hearth carbon bricks. In this paper, a detailed analysis of the erosion behavior of the hearth carbon bricks in a 4000 m³ blast furnace in China was conducted. The changes in the chemical composition and physical properties of the carbon bricks were studied, and the micro structural composition of the residual carbon bricks on the hot face was discussed, leading to the establishment of the erosion mechanism of the hearth carbon bricks. The results indicate that the erosion of the hearth carbon bricks in the 4000 m³ blast furnace is uneven in both the height and circumference directions. In the height direction, the most severe erosion occurs at a distance of 2.1 m below the centerline of the iron tapping hole. In the circumference direction, the most severe erosion mainly occurs directly below the iron tapping hole and in the surrounding area. The overall erosion morphology of the hearth resembles an “elephant foot” shape. After nearly 15 years of usage, the compressive strength of the blast furnace carbon bricks significantly decreased, while the ash content increased noticeably. A large amount of zinc deposition was found between the cracks of the carbon bricks in the furnace and inside the brittle layer of the carbon bricks, effectively proving that the deposition and infiltration of zinc vapor on the surface of the carbon bricks are important reasons for promoting the formation of the brittle layer of the carbon bricks, reducing the resistance of the carbon bricks to molten iron erosion, and increasing the risk of fracture of the furnace carbon bricks.