复合粘结剂对球团高温固结的影响及机理  

Effects and mechanism of composite binder on high-temperature consolidation of pellets

作　　者：韩凤光 杨涛 赵贺喜 汪名赫 王毅璠 龙红明 雷杰 姜涛[1] HAN Fengguang;YANG Tao;ZHAO Hexi;WANG Minghe;WANG Yifan;LONG Hongming;LEI Jie;JIANG Tao(School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China;Meigang Technology Center,Central Research Institute of Baosteel Corporation,Nanjing 210039,China;School of Metallurgical Engineering,Anhui University of Technology,Maanshan 243032,China)

机构地区：[1]中南大学资源加工与生物工程学院,长沙410083 [2]宝钢股份中央研究院梅钢技术中心,南京210039 [3]安徽工业大学冶金工程学院,马鞍山243032

出　　处：《工程科学学报》2023年第9期1450-1458,共9页Chinese Journal of Engineering

基　　金：国家自然科学基金资助项目(52174290);安徽省自然科学基金杰出青年资助项目(2208085J19)。

摘　　要：膨润土是球团矿生产过程中的主要粘结剂,能显著改善原料成球性、提升球团质量,但较高的SiO_(2)和Al_(2)O_(3)含量会造成炼铁生产渣量增加.添加少量有机粘结剂替代部分膨润土已成为改善球团性能的必要手段.本文考察了有机粘结剂P替代部分膨润土对球团高温强度的影响,结合激光闪射法和热重法(TG)研究了有机粘结剂对磁铁矿球团内部结构及传热、传质的影响.结果表明,复合粘结剂可以替代部分膨润土,适量有机组分的增加有利于预热球、焙烧球强度的提升和球团的氧化.主要原因是有机粘结剂P经过高温后热解,并在球团内部形成适量孔隙,球团热传导系数降低,内部升温梯度减缓,避免了球团表层因过快氧化结晶而形成致密的氧化层.同时,细小的孔隙有利于氧气进入球团内部,促进Fe_(3)O_(4)氧化成Fe_(2)O_(3),氧化分数fTGA随着有机粘结剂P的添加而逐渐升高,由90.80%提至92.17%.Iron ore pellets have several substantial advantages,such as high iron grade,low harmful elements,low smelting slag,and low pollution in the production process.Rapidly developing the pelleting process and improving the quality of pellet ores is crucial for achieving the goals of carbon peaking and carbon neutrality in the steel industry.Bentonite,a major binder in the pellet ore production process,can significantly improve the sphericity of raw materials and enhance the pellet quality;however,the higher SiO_(2) and Al_(2)O_(3) content will cause an increase in the slag volume of ironmaking production.An organic binder has the advantages of low dosage and less harmful impurities,which can improve the pellet ore grade and the expansion rate of pellets.Thus,adding a small amount of organic binder to replace part of the bentonite is essential to improving the pellet performance.This study investigates the effect of organic binder P replacing part of bentonite on the high-temperature strength of pellets.The laser flash and thermogravimetric methods were employed to investigate the effects of organic binder on the internal structure,heat transfer,and mass transfer of pellets.The results indicated that bentonite was beneficial in reducing the porosity and high-temperature consolidation of pellets because it could promote the generation of a low-melting-point liquid phase.With increasing bentonite addition,the strength of preheated and roasted pellets increased,and the porosity decreased from 21.82%to 15.68%when bentonite addition increased from 1.1%to 2.0%.Thus,the composite binder could replace a part of the bentonite and significantly improve the strength of preheated and roasted pellets with increasing addition.Moreover,the organic binder P was pyrolyzed at a high temperature and formed pores inside the pellet,resulting in a lower thermal conductivity and a slower internal heating gradient.The thermal diffusivity reduced from 0.321 to 0.266 mm2·s−1,and the heat transfer coefficient decreased gradually from 0.551 t

关 键 词：球团 膨润土 有机粘结剂 氧化固结 孔隙率 

分 类 号：TQ132.32[化学工程—无机化工]