CO与H_(2)气氛下赤铁矿还原动力学及矿相转化机理研究  

Reduction Kinetics of Hematite in CO and H_(2) Atmosphere and the Mechanism Study of Mineral Phase Transformation

作　　者：李新玉 袁帅[1,2,3] 高鹏 王若枫[1,2] 张洪浩 李艳军 LI Xinyu;YUAN Shuai;GAO Peng;WANG Ruofeng;ZHANG Honghao;LI Yanjun(School of Resources and Civil Engineering,Northeastern University,Shenyang 110819,China;National-local Joint Engineering Research Center of High-efficient Exploitation Technology for Refractory Iron Ore Resources,Shenyang 110819,China;State Key Laboratory of Mineral Processing Science and Technology,Beijing 100192,China)

机构地区：[1]东北大学资源与土木工程学院,辽宁沈阳110819 [2]难采选铁矿资源高效开发利用技术国家地方联合工程研究中心,辽宁沈阳110819 [3]矿物加工科学与技术国家重点实验室,北京100192

出　　处：《金属矿山》2023年第9期83-89,共7页Metal Mine

基　　金：国家自然科学基金面上项目(编号:52174240);“十四五”国家重点研发计划项目(编号:2021YFC2902404);矿物加工科学与技术国家重点实验室开放基金项目(编号:BGRIMM-KJSKL-2023-15)。

摘　　要：针对赤铁矿开展了CO和H_(2)气氛下的矿相转化试验,详细研究了还原过程动力学,并采用X射线衍射和扫描电镜对其相变和微观结构变化进行研究,以对比CO和H_(2)矿相转化效果的差异及微观结构演变规律。结果显示,在温度460~620℃范围内,矿相转化温度的提高可以明显加快反应的速率。在CO气氛下,反应模型为收缩核模型,积分形式为G(α)=1-(1-α)^(1/2),其表观活化能为8.35 kJ/mol,指前因子为0.21 min^(-1);在H_(2)气氛下,反应模型为收缩核模型,积分形式为G(α)=1-(1-α)^(1/3),其表观活化能为20.73 kJ/mol,指前因子为4.37 min^(-1)。SEM分析结果表明,在矿相转化过程中,气体的吸附和赤铁矿的矿相转化优先发生在赤铁矿颗粒的表面和裂缝处,反应从颗粒表面和裂隙逐渐向内进行,温度应力和相变应力产生的裂纹为气体扩散提供了通道,这有利于气体及气体产物在颗粒中的内扩散,加速反应的进行。在同等试验条件下,H_(2)的矿相转化效果要优于CO。研究结果可为赤铁矿在H_(2)和CO气氛下矿相转化过程的调控提供理论支撑。Mineral phase transformation experiments under CO and H_(2) atmosphere were carried out for hematite in order to perform kinetic analysis of the reduction process,and the phase transformation and microstructural changes were studied by X-ray diffraction and scanning electron microscopy in order to compare the differences in the mineral phase transformation effects of CO and H_(2) and the microstructural evolution patterns.The results showed that the increase of the mineral phase trans-formation temperature could significantly accelerate the reaction rate in the temperature range of 460~620℃.In CO atmos-phere,the best reation model of the reaction kinetics is shrinkage core model,the integral form is G(α)=1-(1-α)^(1/2),the reation activation energy is 8.35 kJ/mol,and the finger front factor is 0.21 min^(-1).In H_(2) atmosphere,the best reation model of the reaction kinetics is shrinkage core model.The integral form is G(α)=1-(1-α)^(1/3),the reation activation energy is 20.73 kJ/mol,and the finger front factor is 4.37 min^(-1).The SEM analysis results showed that in the process of mineral phase transformation,adsorption of reducing gas and transformation of hematite occur preferentially at the surface and cracks of hema-tite particles,and the reaction proceeds gradually inward from the surface and cracks of particles,and the cracks generated by temperature stress and phase-transformation stress provide channels for gas diffusion,which is conducive to the internal diffu-sion of reducing gas and gas products in the particles and accelerates the reaction.Under the same test conditions,the mineral phase transformation effect of H_(2) is better than that of CO.The results of the study can provide theoretical support for the regu-lation of the mineral phase transformation process of hematite under H_(2) and CO atmosphere.

关 键 词：矿相转化 等温动力学 转化率 反应速率 微观结构 

分 类 号：TD951[矿业工程—选矿] TD925