Timely and full tapping of liquid smelting products is an important condition for forcing the blast-furnace process. Unstable tapping of iron and slag leads to fluctuations of the liquid level in the hearth, changes in the charging rate, and fluctuations in the time the burden stays in the blast furnace. This, in turn, affects the thermal state and the composition of the liquid products. The ratio of tapped slag weight to the hot metal weight is determined by the physical properties of slag and the length and diameter of the taphole. An analysis of the operation of the EVRAZ NTMK blast furnaces revealed substantial fluctuations of this ratio. When the volume of tapped slag is 340 to 360 kg per ton of pig iron, the slag/metal weight ratio is between 200 and 850 kg per ton of pig iron. The objective is to analyze the causes of unstable tapping and the effect of the instability on the furnace performances using the laws of fluid mechanics. It is assumed that the melt flow in the taphole is stratified. The effect of the slag properties and the dimensions of the taphole on the velocity of the melt and, hence, on the slag/metal weight ratio in the taphole is studied. Since the velocity of the melt depends on its physical properties, a mathematical model was developed to assess the slag/metal weight ratio from the viscosity of the slag and the dimensions of the taphole. The results of modeling are validated against the industrial data acquired by the EVRAZ NTMK. It was established that an increase in the tapped slag/metal weight ratio leads to worse performance and lower vanadium recovery from pig iron.

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冶炼产品出钢不稳定对 Evraz Ntmk 高炉性能的影响

液态冶炼产品的及时足量出钢是强制高炉工艺的重要条件。出铁和炉渣不稳定导致炉缸液位波动、装料率变化、炉料在高炉内停留时间波动。这反过来又会影响液体产品的热状态和组成。出钢渣重量与铁水重量之比由渣的物理性质和出铁口的长度和直径决定。对 EVRAZ NTMK 高炉运行的分析揭示了该比率的大幅波动。当出渣量为每吨生铁 340 至 360 公斤时，炉渣/金属重量比在每吨生铁 200 至 850 公斤之间。目的是利用流体力学定律分析出钢不稳定的原因以及不稳定对熔炉性能的影响。假设出铁口中的熔体流动是分层的。研究了炉渣特性和出铁口尺寸对熔体速度的影响，从而对出铁口中的渣/金属重量比的影响进行了研究。由于熔体的速度取决于其物理特性，因此开发了一个数学模型，以根据熔渣的粘度和出铁口的尺寸来评估熔渣/金属的重量比。建模结果根据 EVRAZ NTMK 获取的工业数据进行验证。已经确定，出钢渣/金属重量比的增加会导致性能变差和生铁中钒回收率降低。