球团矿氨还原特性  

Characteristics of ammonia reducing pellets

作　　者：杨佳龙 胡正洪 李家新 从俊强 米澳 张晓萍 温宝良[1] YANG Jialong;HU Zhenghong;LI Jiaxin;CONG Junqiang;MI Ao;ZHANG Xiaoping;WEN Baoliang(School of Metallurgical Engineering,Anhui University of Technology,Ma’anshan 243032,Anhui,China;Technology Center,Ma’anshan Iron and Steel Co.,Ltd.,Ma’anshan 243003,Anhui,China)

机构地区：[1]安徽工业大学冶金工程学院,安徽马鞍山243032 [2]马鞍山钢铁股份有限公司技术中心,安徽马鞍山243003

出　　处：《钢铁》2025年第1期29-39,共11页Iron and Steel

基　　金：安徽省重大产业创新计划资助项目(AHZDCYCX-LSDT2023-01);国家自然科学基金青年基金资助项目(52204330)。

摘　　要：采用氢基竖炉直接还原替代传统高炉炼铁,可以有效减少大量二氧化碳排放。然而,氢的储存和运输成本较高,而氨作为一种备受关注的储氢介质,具备成熟的制备技术以及低廉、便利的储运方式。然而,对于不同温度下球团矿的氨还原动力学,以及温度对球团矿氨还原后相组成的影响,目前的研究仍显不足。因此,系统地考察了温度对球团矿氨还原热力学与动力学及还原产物的影响,并将其与氢还原特性进行了对比研究。研究结果表明,氨还原赤铁矿相较于氢具有更低的ΔG^(θ)(标准吉布斯自由能)值,但由于氨分解反应的存在,使得700~850℃下还原时氮化铁具有较窄的生成区间,磁铁矿主要通过氨及氨分解生成的氢还原为浮氏体然后至铁。温度越高,球团矿氨还原程度越高,氨还原赤铁矿能力要弱于氢,氨的分解反应对氨还原反应速率具有负面影响,且球团矿氨还原的活化能为71.05 kJ/mol,也大幅高于氢。球团矿氨还原前期(还原时间t≤2340 s)受界面化学反应控制,还原后期(还原时间t>2340 s)受气体内扩散控制。XRD和电子显微镜元素扫描结果显示,氮化铁与铁及其氧化物共存,高还原温度下,还原铁层更容易形成细小结构,使得球团矿还原后期的动力学限制性条件为还原气体内扩散。研究结果对减少炼铁工业温室气体排放、推动炼铁过程的环保和可持续发展具有一定意义。The utilization of hydrogen-based vertical furnaces for direct reduction,in lieu of traditional blast furnaces,can substantially decrease carbon dioxide emissions.However,the high costs associated with hydrogen storage and transportation present significant challenges.Ammonia,as a promising hydrogen storage medium,provides established preparation technology and offers low-cost,convenient storage and transportation methods.Nevertheless,research on the kinetics of ammonia reduction of pellet at varying temperatures,as well as the effects of tem‐perature on the phase composition following ammonia reduction,remains inadequate.Therefore,this study systematically investigates the effects of temperature on the thermodynamics and kinetics of ammonia reduction of pellets,and compares these characteristics with hydrogen reduction.The findings indicate that theΔG^(θ)(Standard Gibbs free energy)value for ammonia reduction of hematite is lower compared to hydrogen.However,due to the presence of ammonia decomposition reactions,iron nitride has a narrower formation range at 700-850℃during reduction.Magnetite is primarily reduced to wüstite and iron through hydrogen generated from ammonia and its decomposition.As the temperature increases,the extent of ammonia reduction of the pellets also increases,but ammonia has a weaker reduction capability compared to hydrogen.The decomposition reaction of ammonia negatively impacts the reduction rate,and the activation energy for ammonia reduction of pellets is 71.05 kJ/mol,which is considerably higher than that for hydrogen.During the early stage of ammonia reduction of pellets(reduction time t≤2340 s),the process is controlled by interfacial chemical reactions,while in the later stage(reduction time t>2340 s),it is controlled by gas-phase diffusion.XRD and electron microscope elemental scanning results reveal that iron nitride coexists with iron and its oxides.At high reduction temperatures,the reduced iron layer is more likely to form a fine structure,which limits the kinetic c

关 键 词：可持续炼铁 氨还原 氢还原 球团矿 还原动力学 高炉炼铁 氢基竖炉 环保 

分 类 号：TF046.6[冶金工程—冶金物理化学]