新型全废钢电弧炉炼钢工艺基础研究

Electric arc furnace (EAF) is one of the important steelmaking methods in the world, which has advantages of short process, low energy consumption, resource-recycling function, environment-friendly and so on. Aiming at solving the problems of slow melting of scrap, poor fluidity of bath, difficulty of desulphurization and dephosphorization, dioxin control that the traditional EAF process is facing with, a new advanced electric arc furnace steelmaking process with full scrap is put forward. Based on fundamental theory of steelmaking and with help of a 500kg trial EAF, high temperature jets injection, online flue gas analysis, high temperature thermography technique and combination of numerical model and water model, this study carries out fundamental research on new advanced EAF steelmaking process with full scrap, which includes: researching on the melting of steel scrap and exploring fast-melting mechanism; studying the fluid flow of gas-slag-metal in the bath of scrap-EAF and learning the reaction kinetics in low carbon bath; studying the oxygen-powder bottom blowing process for EAF and building kinetics model for dephosphorization; studying the dissolving of N from liquid steel to CO2 bubble in the hearth and making the bottom CO2 blowing denitrogenation mechanism clear. And this study’s target is to provide theoretical basis for the new advanced EAF steelmaking process with full scrap which has low energy consumption, short tap-to-tap time, green production and high steel cleanness.

电弧炉炼钢是世界主要炼钢方法之一，具有流程短、能耗低、资源循环、环境友好等特点。针对传统电弧炉炼钢工艺存在废钢熔化慢、熔池流动性差、脱磷脱氮困难、二噁英控制难等问题，提出新型全废钢电弧炉炼钢工艺的概念。基于炼钢基础理论，通过热态射流喷吹及 500kg 级实验电弧炉试验，依靠高温成像、在线烟气分析等检测方法，结合数值模拟和水模型，开展新型全废钢电弧炉炼钢工艺基础研究，主要包括：研究废钢熔化行为，探究全废钢电弧炉内废钢的快速熔化机理；研究全废钢冶炼气-渣-金三相流流体流动，掌握低碳条件下电弧炉熔池内的反应动力学；研究电弧炉底部喷吹氧气-粉剂脱磷，建立脱磷过程动力学模型；研究CO2气泡与熔池中氮的界面溶解、反应行为，明确电弧炉底吹CO2脱氮界面机理。实现能量消耗低、冶炼周期短、绿色洁净化的新型全废钢电弧炉炼钢工艺。

电弧炉炼钢以废钢为主要原料，废钢熔化速度慢，冶炼周期长，且熔清后C含量低，熔池C-O反应缺乏，受传统工艺技术及装备水平限制，高效、深度、低成本去除钢中有害杂质元素的技术瓶颈长期未能突破，严重制约了短流程炼钢工艺发展。基于此，本项目组借助于热模实验及数值模拟方法研究了熔池内废钢快速预热、熔化机理，利用水模型实验分析了电弧炉熔池内废钢熔化的影响因素，在此基础上，建立了电弧炉熔池内不同堆密度和自由堆料条件下废钢熔化时间计算模型。本项目创造性提出了电弧炉埋入式气-固喷吹冶炼新工艺，通过向熔池内部直接喷射石灰粉或碳粉，改善熔池冶金动力学条件，并采用水模拟和数值模拟相结合的方式研究了复吹搅拌熔池流场特性，探明了最佳的布置方式，通过开展热态实验和工业实验探明了气-固喷吹的脱磷机理和脱磷效果。采用多种手段对底吹CO2过程钢液C-O反应机理、脱氮机理进行系统研究，探明了CO2喷吹脱氮规律及脱氮极限。基于以上研究形成了集废钢预热、高效供能与快速熔炼、喷粉脱磷与底吹脱氮等技术于一体的“能量消耗低、冶炼周期短、绿色洁净化”电弧炉炼钢生产工艺理论。