铁矿烧结过程超细颗粒物形成调控与减排技术研究

Ultra-fined particulate matters (UPM) emitted from iron ore sintering flue gas take the first place of iron & steel industry. Since UPM is rich in alkali chloride of high specific resistance, the mainly-applied electrostatic precipitator shows low efficiency.This project provides the technical idea of regulating the transformation path for alkali metals in sintering process, with the purpose of improving electrostatic precipitation efficiency. Through studying the high-temperature reaction behavior of alkali metals & chlorine and the factors influencing the chlorination evaporation, the mechanism of inhibiting alkali chloride formation in sintering process will be revealed. Through studying the reaction behavior of alkali metal reduction evaporation, the formation mechanism of alkali sulphates and carbonates will be revealed, thereby establishing the control theory of UPM on the basis of regulating forms of alkali metals. Based on the research above, the pre-granulation process for treating materials with high contents of alkali metals will be developed. Through studying the influence of material parameters and structural parameters of granules on forms of removed alkali metals, the granules with reasonably distributed high alkali metal content materials, fuels and fluxes will be constructed, thereby regulating the reaction atmosphere and chemical composition of high alkali metal content materials in sintering process. Then the transformation of alkali metals in UPM to achloride forms will be realized, and the emission reduction techniques of removing UPM efficiently will be formed. This project will provide novel approach for reducing UPM emission in economic and efficient manner, which is of great significance for green steel manufacturing.

铁矿烧结烟气排放的超细颗粒物居钢铁工业首位。因烧结产生的超细颗粒物富含高比电阻碱金属氯化物，主流采用的静电除尘器对其减排效率低。本项目提出调控烧结过程碱金属转化途径以提高静电除尘效率的技术思路，拟通过研究碱金属与氯元素的高温反应行为及其氯化挥发的影响因素，揭示抑制烧结过程碱金属氯化物形成的机理；通过研究碱金属还原挥发的反应行为，揭示低比电阻碱金属硫酸盐和碳酸盐的形成机制，建立基于调控碱金属形态转化的超细颗粒物控制理论；进而开发高碱金属物料的预制粒工艺，通过研究原料参数、小球结构参数对碱金属脱除形态的影响，构建高碱金属物料、燃料、熔剂分布合理的制粒小球，调控高碱金属物料在烧结过程的反应气氛和组成，实现超细颗粒物中碱金属向非氯化物的形态转化，形成超细颗粒物高效除尘的减排技术。本项目可为烧结烟气超细颗粒物经济、高效减排提供新方法，对钢铁绿色制造具有重要意义。

围绕烧结过程超细颗粒物高效控制，开展铁矿烧结过程超细颗粒物形成调控与减排技术研究。针对烧结物料中典型类型碱金属，系统研究了烧结过程碱金属的反应热力学，阐明了烧结过程碱金属的转化行为，明晰了温度、气氛、化学组分影响碱金属氯化挥发的规律，揭示了抑制碱金属氯化挥发的机制；查明了碱金属还原脱除行为，明晰了温度、气氛、化学组分影响碱金属还原挥发的规律，揭示了还原脱除的碱金属形态转化机制；揭示了还原脱除碱金属的形态转化行为与向超细颗粒物转化机制，建立了烧结过程抑制碱金属氯化挥发、促进其还原挥发，并向非氯化物形态转化的基础理论。. 在理论研究基础上，查明了利于碱金属非氯化物形态脱除的气氛、组分、小球结构等适宜条件，构建了高碱金属含量物料分流制粒、分层分布的强化调控方法，开发了基于碱金属形态调控的超细颗粒物控制技术：通过调控高反应活性生物质木炭、钙基熔剂生石灰在高碱金属含量物料小球中的偏析分布，构建了适宜于抑制碱金属氯化挥发、促进其还原脱除的反应环境，将超细颗粒物中碱金属以氯化物为主转化为以硫酸盐、其他形态为主，超细颗粒物比电阻1012Ω‧cm以上降低至1011Ω‧cm以下，满足高效电除尘的需求，实现了烧结过程超细颗粒物经济、高效控制。. 开发的基于碱金属形态调控的超细颗粒物控制技术与湖南华菱湘潭钢铁有限公司、山西太钢不锈钢股份有限公司等国内大型钢铁企业推广应用，为烧结烟气超低排放和钢铁工业绿色发展具有积极推动作用，相关研究成果发表学术论文10篇（SCI 检索8篇、EI检索 1篇），获授权国家发明专利7项，获湖南省科技进步二等奖1项、中国冶金教育学会优秀博士学位论文奖1项。