转炉多元喷吹提钒过程熔池旋流特征及其机理研究

Converter vanadium extraction process is aimed at extracting vanadium and keeping carbon under low temperature, and the kinetic condition of molten pool is poor. In order to improve thermodynamics and kinetic condition and increase vanadium recovery rate, the concept of mixing N2, CO2, or their mixed gas into oxygen jet is put forward during vanadium extraction process, realizing extracting vanadium by multiple gases injection. This concept is adopted to use endothermic effects and jet flow energy of N2 and CO2 to control the temperature of molten pool and intensify stirring. The reaction limitation and selective oxidation will be researched through thermodynamic calculation and analysis, and the 3-D full size three phase coupling model of "gas-slag-metal" for converter vanadium extraction by multiple gases injection will be established through numerical simulation by Fluent and module coupling, unsteady calculations and water simulation experiment. Besides, the characteristics of muti-stream supersonic gas will be studied during converter mutiple gases injection process, the flow performance of molten pool will be revealed, which is acted by coupling of top-blown multiple gases jet and multi-stream flow of bottom blowing. The rotational flow index of molten pool will be proposed and confirmed and stirring power can be quantified. The mechanism of converter vanadium extraction by multiple gases injection will be verified through high temperature experiment, together with the analysis on liquid metal, slag and furnace gas. The thermodynamics and kinetic condition during converter vanadium extraction process will be improved through the research, which can also provide basic data and theoretical support for process optimization.

转炉提钒是在低温条件下实现“提钒保碳”，熔池动力学条件较差。为改善提钒热力学和动力学条件，提高钒回收率，本课题提出在转炉提钒顶吹氧气射流中混入N2、CO2或两者混合气体，实现O2-N2、O2-CO2或O2-N2-CO2多元气体喷吹提钒，利用N2、CO2的吸热效应和射流动能，控制提钒熔池温度并强化搅拌。拟通过热力学计算与分析探究转炉多元喷吹提钒的反应限度及选择性氧化；通过Fluent数值模拟结合模块耦合及非稳态计算和水模拟实验，建立转炉多元喷吹提钒的三维全尺寸“气-渣-金”三相耦合模型，研究转炉多元喷吹的多流股超音速气体射流特性，揭示顶吹多元气体射流与底吹多流股耦合作用下提钒熔池的流动特征，提出并确定提钒熔池旋流指数，量化熔池搅拌功；通过高温提钒实验，结合金属液、炉渣及炉气分析，探明转炉多元喷吹提钒机理。通过课题研究，改善转炉提钒热力学和动力学条件，为优化转炉提钒工艺提供基础数据和理论支撑。

转炉提钒是在低温条件下实现“提钒保碳”，熔池动力学条件较差。为改善提钒热力学和动力学条件，提高钒回收率，本项目提出多元气体喷吹提钒的思路，利用N2、CO2的吸热效应和射流动能，控制提钒熔池温度并强化搅拌。.项目基于多元喷吹的气体特性，分析了转炉多元喷吹提钒热力学和动力学，掌握了多元喷吹提钒过程元素的选择性氧化转化温度关系式，建立了转炉多元喷吹提钒条件下的物料平衡和能量平衡模型，发现CO2在化学反应热和物理吸热两方面的冷却效果都强于O2、N2，在氧气射流中混入N2和CO2，当CO2喷吹比例为46.6%时，体系热量收支平衡。研究了转炉多元喷吹提钒的顶底复吹熔池搅拌能量密度，获得了合理的熔池搅拌能计算方法，发现CO2利用率和氧枪枪位显著影响熔池搅拌能量密度。.项目利用Fluent软件模拟研究多元多流股超音速射流的速度场、压力场、密度场以及射流轨迹等参数，发现多元气体进入氧枪喷头后压力快速降低，速度迅速增大，随着射流的继续扩散，多元气体的射流速度差异逐渐减小，部分氧气被二氧化碳和氮气代替对钢液冲击影响较小，氮气射流速度最大，氧气次之，二氧化碳最小。并结合水力学模型测定多元喷吹条件下的混匀时间、冲击深度和冲击面积，研究气泡上浮过程、熔池冲击凹坑形貌及熔池旋流特征，发现利用多元喷吹增加气体旋流，在一定程度上能增加射流与熔池的接触面积，加快提钒熔池流动速度。.在此基础上，利用20kg感应炉完成了转炉多元喷吹提钒的反应速率及提钒机理的高温实验研究，发现高温喷吹CO2时渣中（V2O5）含量达到8.91%，比常规冶炼工艺增幅达到26.03%，验证了多元喷吹条件的提钒保碳效果，探明了转炉多元喷吹提钒机理。通过项目研究，改善转炉提钒热力学和动力学条件，为优化转炉提钒工艺提供基础数据和理论支撑。.项目执行过程共发表论文7篇，授权发明专利2项，培养研究生2名，完成了基金的成果目标。