铝粒尺寸及入炉高度对运动轨迹的影响

The influence of aluminum particle size and launch altitude on the movement trajectory of aluminum particles

二次精炼过程中,铝是钢液进行脱氧及合金化的主要物料之一,但纯铝的密度小于钢液,能否穿越渣层与钢液接触及接触时间对铝的脱氧效果和钢中溶解铝的含量有直接影响。在忽略铝的熔化、溶解及化学反应的情况下,通过对铝粒运动过程受力分析,建立铝粒在气-渣-钢相内的三维运动数学模型,明晰铝粒尺寸及入炉高度对铝粒运动轨迹的影响。结果表明:在渣层厚度为70 mm且入炉高度为1~1.5 m的情况下,1 mm和5 mm的铝粒在渣钢界面处波动;入炉高度为1 m时,粒径为10 mm的铝粒停留在渣钢界面处,但在入炉高度为1.5 m及以上时可以进入钢液;20 mm及以上尺寸的铝粒可以进入钢液。在入炉高度为1 m时、30 mm尺寸的铝粒在钢液中的停留时间与深度相较于20 mm的基础上分别增加22.86%和50.00%;在铝粒尺寸为20 mm时、入炉高度为1.5 m时的铝粒在钢液中的停留时间与深度在1 m的基础上分别增加5.71%和10.00%。增加钢渣界面张力、减小钢铝界面张力或增加渣铝界面张力有利于铝粒进入钢液,而铝粒的尺寸大于20 mm,界面张力对铝块运动几乎没有影响;增大密度会使钢芯铝在钢液中停留更长时间,有利于钢液脱氧。

In the secondary refining process,aluminum is one of the main materials for deoxidization and alloying of molten steel,but the density of pure aluminum is less than that of molten steel.Whether it can pass through the contact between slag layer and molten steel and the contact time have a direct impact on the deoxidization effect of aluminum and the content of dissolved aluminum in steel.In this paper,the three-dimensional motion mathematical model of aluminum particles in gas-slag-steel is established by analyzing the force of aluminum particles during the movement process,ignoring the melting,dissolution and chemical reaction of aluminum.The influence of aluminum particle size and launch altitude on the trajectory of aluminum particles is clarified.The results show that when the slag layer thickness is 70 mm and launch altitude is 1-1.5 m,the aluminum particles of 1 mm and 5 mm fluctuate at the slag-metal interface.When launch altitude is 1 m,the aluminum particles with a particle size of 10 mm stay at the slag-metal interface,but they can enter the molten steel when launch altitude is 1.5 m or above.Aluminum particles of 20 mm and above can enter the molten steel.When launch altitude is 1 m,the residence time and depth of 30 mm aluminum particles in molten steel increase by 22.86%and 50.00%respectively compared with 20 mm.When the aluminum particle size is 20 mm,the residence time and depth of aluminum particles in molten steel increase by 5.71%and 10.00%respectively on the basis of 1 m when launch altitude is 1.5 m.Increasing the steel slag interfacial tension,reducing the steel-aluminum interfacial tension or increasing the slag-aluminum interfacial tension is beneficial to the entry of aluminum particles into the molten steel.When the size of the aluminum particles is greater than 20 mm,and the interfacial tension has little effect on the movement of the aluminum block.Increasing the specific gravity will make the steel core aluminum stay in the molten steel for a longer time,which is beneficial to the deoxidization of the molten steel.