Abstract: The liquid slag dry granulation and waste heat recovery technology solves the problem of waste heat loss and environmental pollution caused by the existing water quenching process of liquid slag in metallurgical industry, which plays an important role in the implementation of energy saving and emission reduction strategy. In order to improve the resource utilization of slag pellets and reduce the equipment investment, the addition of auxiliary gas quenching wind at the edge of the pelletizer is proposed to enhance the palletizations effect and improve the waste heat recovery efficiency. However, the mechanism of the effect of gas quenching wind on centrifugal granulation and the influence pattern are still unclear in the current study. A three-dimensional granulation model with gas quenching wind was established using the SST k-ω turbulence model. And the effects of gas quenching wind on the granulation effect, the flight velocity of waste particles and the cooling effect of rotor cup were investigated by using the VOF method. The changing rule of the horizontal flight speed of liquid droplets under different gas quenching wind conditions was investigated to provide reference basis for optimizing the flight trajectory of liquid droplets and the spatial design of granulation silo. Findings indicated that while increasing air volume shifted particle size distribution to larger ranges, it benefited the slag particles' sphericity. The gas quenching wind effectively induced particle fragmentation within the air flow range of 4~6 m3/h, with enhanced cooling effects when air flow surpassed 2 m3/h. When selecting the air flow, the air flow of 1 m3/h can be selected when considering the granulation effect and flight speed only, and the flow of 2 m3/h was the best when considering the cooling effect comprehensively. Using a ring slit for air venting resulted in the smallest average diameter of slag particles, lower wall temperatures near the rotating cup, moderate flight speed, and superior sphericity compared to a state without gas quenching wind.

Key words: blast furnace slag, centrifugal granulation, splitting mode, gas quenching wind, solid waste utilization, numerical simulation

摘要： 在熔渣粒化过程中引入辅助气淬风，降低转杯温度同时强化熔渣粒化效果，提高了渣粒利用率且增加了系统使用寿命。建立了带有气淬风的三维熔渣粒化模型，采用SST k-ω湍流模型，利用VOF方法研究了气淬风对熔渣粒化效果、废渣颗粒飞行速度以及转杯冷却效果的影响。探究了不同气淬风条件下熔渣颗粒水平飞行速度的变化规律，为优化颗粒飞行轨迹及粒化仓空间设计提供参考依据。结果表明，增大风量使熔渣粒径分布向较大区间移动，但有利于改善渣粒球形度。气淬风在4~6 m3/h的风量范围内能产生有效的破碎作用，当风量大于2 m3/h时，冷却效果较好。采用环形缝隙出风时，渣粒平均直径最小，且靠近转杯壁面的温度较低，飞行速度适中，球形度优于无气淬风状态。

关键词: 高炉熔渣, 离心粒化, 分裂模式, 气淬风, 固废利用, 数值模拟