浇注钢包环出钢口吹氩控制下渣新工艺应用基础研究

Considering the demands on the stable and economical production of clean steel as well as the current problems of slag carry-over control during continuous casting ladle teeming process, a new controlling slag carry-over process with gas injected into the ladle around the tapping hole will be investigated. Some important theoretical and key technical issues of this new technology will be researched to lay an important theoretical and applied foundation for the industrialization of it. With the theoretical and cold experimental study in laboratory, during ladle teeming process with gas injected into the ladle around the tapping hole, the mechanisms to control the slag carry-over caused by vortex and drain sink formation will be revealed. The mechanism of slag-metal emulsion and slag entrapment will also be revealed and the argon blowing parameters as well as the gas blowing element both to control the slag carry-over and to avoid the slag-metal emulsion and slag entrapment will be presented. A mathematical model will be established to describe the gas-melt-slag multi-phase flow during ladle teeming process with gas injected into the ladle around the tapping hole and the effects of operation parameters on controlling slag carry-over will be investigated. By the field application test, the application feasibility of the new controlling slag carry-over process will be presented. So the present study will have important theoretical and practical significance in the clean steel production and it will be beneficial for the clean steel in improving yield, reducing cost and stabilizing production. And it will also provide some theoretical guidance and reference for the slag carry-over control during drainage of other metallurgical reactors.

针对稳定、经济地生产洁净钢的需求和当前连铸钢包下渣控制存在的问题，进行浇注钢包环出钢口吹氩控制下渣新工艺研究，对涉及此新工艺的若干重要理论与关键技术问题开展深入研究，为此新控制钢包下渣工艺技术的工业化奠定重要的理论和应用基础。通过实验室的理论与冷态实验研究，揭示环出钢口吹氩下钢包浇注过程控制汇流旋涡和排流沉坑下渣的机理，揭示渣钢乳化和卷混的机理并研究设计出合理的既能控制下渣又能避免渣钢乳化和卷混的吹氩参数及环钢包出钢口吹气元件；建立描述环出钢口吹氩下钢包浇注过程气-钢液-渣多相流行为的理论模型，揭示过程和操作参数对控制下渣的影响规律；通过企业的现场应用试验，提出浇注钢包环出钢口吹氩控制下渣新工艺应用可行性。本项目研究对洁净钢的生产具有重要的理论和现实指导意义，能提高钢包浇注过程的钢水收得率，降低成本，稳定洁净钢的生产，本研究还会对其它冶金反应器排流过程的下渣控制研究具有借鉴和理论指导意义。

基于稳定、经济地生产洁净钢的需求和当前连铸钢包下渣控制存在的问题，开展了浇注钢包环出钢口吹氩控制下渣新工艺研究。通过实验室的理论与冷态实验研究，揭示了环出钢口吹氩下钢包浇注过程控制汇流旋涡和排流沉坑下渣的机理，即：钢包内钢液的周向旋转速度是形成汇流漩涡的主要原因，环出钢口吹入氩气后，会使流体在经过氩气环后其周向旋转速度大幅降低甚至消失，故该新工艺可以消除因汇流漩涡所引起的下渣；流向出钢口的流体经过氩气环时因受气泡浮力作用而使其速度减小，因此该新工艺虽不能消除排流沉坑下渣但可降低其下渣临界高度。揭示了渣钢界面行为机理，即：当钢包内渣层较薄时，较小吹氩量下，气泡直接穿过渣层进入大气中；较大气量吹氩时，会在吹氩口的正上方形成无渣层的圆凸区，即出现渣眼现象；随气量进一步增大，会发生卷渣现象；但在厚渣层下，除了会出现渣眼和卷渣这两种渣钢界面现象外，吹氩不当会引起泡沫渣现象。揭示了过程和操作参数对控制下渣的影响规律，通过研究发现，渣层较薄时，随环出钢口吹氩量增加，钢包浇注过程下渣量呈减小趋势，且大气量控制下渣效果显著；渣层较厚时，在不产生泡沫渣的气量范围内，不同气量的控制下渣效果相差不大。建立了描述环出钢口吹氩下钢包浇注过程气-钢液-渣多相流行为的理论模型，并对该工艺过程进行了数值仿真。研制出了环钢包出钢口吹气元件并提出了合理的既控制下渣又避免渣钢乳化和卷混的吹氩操作工艺，为该新工艺经济高效地解决钢包浇注过程下渣控制难题提供理论依据和指导。本项目研究对洁净钢的稳定、经济地生产具有重要的理论和现实指导意义，能提高钢包浇注过程的钢水收得率，降低成本，稳定洁净钢的生产。本项目研究方法和研究成果还会对其它冶金反应器排流过程（高炉出铁、转炉出钢、中间包浇注）的下渣控制研究具有借鉴和理论指导意义。