含铁黏结剂对磁铁矿球团氧化动力学的影响  

Effect of iron-containing binder on oxidation kinetics of magnetite pellets

作　　者：邱勇虎 罗果萍[1] 任杰 郝帅[1] 柴轶凡[1] QIU Yonghu;LUO Guoping;REN Jie;HAO Shuai;CHAI Yifan(School of Materials and Metallurgy,Inner Mongolia University of Science and Technology,Baotou O14010,Nei Mongol,China;School of Materials Science and Engineering,Shanghai University,Shanghai 201900,China)

机构地区：[1]内蒙古科技大学材料与冶金学院,内蒙古包头014010 [2]上海大学材料科学与工程学院,上海201900

出　　处：《中国冶金》2024年第4期39-48,共10页China Metallurgy

基　　金：内蒙古自治区高等学校碳达峰碳中和研究专项资助项目(STZX202231);内蒙古自治区科技重大专项计划项目(2021ZD0016);国家重点研发计划资助项目(2020YFC1909105);国家自然科学基金资助项目(51364030)。

摘　　要：通过改变磁铁矿球团中含铁黏结剂的配比(0%、4%和8%),进行了球团氧化的动力学研究。首先利用TG-DTG-DSC分析确定了磁铁矿粉氧化的温度范围为240.1~1029.7℃,其后在温度400~1000℃和时间0~15 min内对球团进行了等温氧化动力学试验。根据反应过程中球团FeO含量随氧化时间的变化数据,分析了球团氧化度的变化规律以及含铁黏结剂对球团氧化度的影响。分别采用0级、1级和2级基元反应级数的f(C)-t图(C为质量分数,t为时间)对试验数据进行了拟合。结果表明,球团氧化反应符合1级反应的动力学规律,并确定了不同含铁黏结剂配比条件下反应的速率常数k。最后根据未反应核收缩模型和Arrhenius方程计算了反应的活化能,并判断了反应的限制性环节。研究显示,在低温段(400~700℃),含铁黏结剂配比为0%、4%和8%时,氧化反应的活化能依次为23.40、20.83、20.73 kJ/mol,表明含铁黏结剂可以加速球团的氧化进程,原因在于黏结剂结晶水的析出增加了球团内部的孔隙率,使气体O_(2)与磁铁矿的接触更加充分,球团氧化速率更快;但含铁黏结剂配比由4%增加到8%时,球团氧化速率增加幅度较小,原因在于黏结剂中结晶水的分解和扩散影响了球团的氧化。在高温段(800~1000℃),不同含铁黏结剂的反应活化能依次为43.37、35.16、35.98 kJ/mol,呈先降后升的趋势,表明过量的含铁黏结剂反而不利于氧化反应的进行。研究结果对优化含铁黏结剂配比、改善球团矿质量和指导球团矿生产具有重要意义。The kinetics of pellet oxidation was studied by changing the ratio of iron-containing binders in magnetite pellets to 0%,4%and 8%.Firstly,the temperature range of magnetite powder oxidation was determined at 240.1-1029.7℃by TG-DTG-DSC analysis,and then isothermal oxidation kinetics experiments were carried out on pellets at 400-1000℃for 0-15 min.According to the change data of FeO content in pellets with oxidation time during the reaction process,the change law for the oxidation degree of pellets and the influence of iron-containing binder on the oxidation degree of pellets were analyzed.The experimental data were fitted by f(C)-t diagrams of 0,1st and 2nd order elementary reaction orders,respectively.The results show that the pellet oxidation reaction conforms to the kinetic law of the 1st order reaction,and the reaction rate constant k under different iron-containing binder ratios is determined.Finally,the activation energy of the reaction was calculated based on the unreacted core shrinkage model and the Arrhenius equation,and the limiting links of reaction were determined.The results show that in the low temperature section(400-700℃),the activation energy of the oxidation reaction is 23.40,20.83,20.73 kJ/mol respectively when the proportion of iron-containing binder is 0%,4%and 8%,which indicates that the iron-containing binder can accelerate the oxidation process of pellets.The reason is that the precipitation of crystal water in binder increases the porosity of pellets,makes the contact between gas O_(2) and magnetite more sufficient,and the oxidation rate of pellets is faster.However,when the proportion of iron-containing binder increases from 4%to 8%,the oxidation rate of pellets increases slightly,because the decomposition and diffusion of crystal water in binder affect the oxidation of pellets.In the high temperature section(800-1000℃),the reaction activation energy of different iron-containing binders are 43.37,35.16,35.98 kJ/mol,respectively,showing a trend of decreasing first and then increas

关 键 词：含铁黏结剂 球团矿 氧化动力学 未反应核收缩模型 活化能 

分 类 号：TF046.6[冶金工程—冶金物理化学]