以超纯磁铁精矿为原料通过H?gan?s工艺制备高纯还原铁粉  

Preparation of high-purity reduced iron powder by Höganäs process from ultra-pure magnetite concentrate

作　　者：吴金甜 徐斌 董中林 周玉娟 徐良平 李光辉 姜涛 WU Jin-tian;XU Bin;DONG Zhong-lin;ZHOU Yu-juan;XU Liang-ping;LI Guang-hui;JIANG Tao(School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China;State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China)

机构地区：[1]School of Minerals Processing and Bioengineering,Central South University,Changsha 410083,China [2]State Key Laboratory of Powder Metallurgy,Central South University,Changsha 410083,China

出　　处：《Journal of Central South University》2023年第9期3006-3020,共15页中南大学学报（英文版）

基　　金：Project(2020YFC1909800) supported by the National Key R&D program of China;Project(1053320210076) supported by the Fundamental Research Funds for the Central Universities,China;Project supported by the State Key Laboratory of Powder Metallurgy,China。

摘　　要：在本研究中,以铁品位为68.38%、硅含量为2.33%的优质磁铁精矿为原料通过反浮选获得了铁品位为72.12%、硅含量为0.09%的超纯磁铁精矿。以超纯磁铁精矿为原料,在1075℃下煤基还原18 h、850℃下氢气还原50 min制备了铁品位为99.06%的高纯还原铁粉。高纯还原铁粉的松装密度、流动性和压缩性分别为2.34 g/cm^(3),9.01 s/(50 g)和6.55 g/cm^(3),达到了粉末冶金用铁粉企业标准(MHF/QB-2016)中MHF80·235(优等)级。用高纯还原铁粉通过共沉淀法制备磷酸铁锂,其首次充电比容量达168.20 m A·h/g。铁鳞经过1075℃煤基还原36 h、14 m T磁选、850℃氢气还原60 min得到铁品位为98.47%的二次还原铁粉,其松装密度、流动性和压缩性分别为2.30 g/cm^(3),10.39 s/(50 g)和6.41 g/cm^(3)。与铁鳞相比,超纯磁铁精矿不仅可省去赫格纳斯工艺中的磁选环节,而且其煤基还原和氢气还原环节所需的时间更短,得到的还原铁粉铁品位更高、工艺性能更佳。本文提出了还原铁粉工艺性能的改善机理:还原铁粉的粗颗粒占比和铁品位的提高可以明显改善其松装密度和压缩性,粗颗粒占比的增加也会改善还原铁粉的流动性。In this study,firstly,an ultra-pure magnetite concentrate with 72.12%Fe and 0.09%Si was obtained by reverse flotation from superior magnetite concentrate with 68.38%Fe and 2.33%Si.Then,using the ultra-pure magnetite concentrate as raw material,high-purity reduced iron powder with Fe grade of 99.06%was prepared by Höganäs process,of which bulk density,mobility and compressibility were 2.34 g/cm^(3),9.01 s/(50 g)and 6.55 g/cm^(3),respectively.The high-purity reduced iron powder reached the MHF80·235(superior)grade in the enterprise standard of iron powder for powder metallurgy(MHF/QB-2016).We used it to prepare lithium iron phosphate with first charge capacity of 168.20 mA·h/g by coprecipitation method.Compared with iron scale,the ultra-pure magnetite concentrate did not require a magnetic separation in Höganäs process,and needed a shorter coal-based and hydrogen reduction time.Besides,its reduced iron powder had a higher Fe grade and better process performance.Mechanisms for improvement of the process performance of reduced iron powder were proposed:an increase in the coarse particles percentage and Fe grade of reduced iron powder could significantly improve its bulk density and compressibility,and an increase in the coarse particles percentage also could improve its mobility.

关 键 词：反浮选 超纯磁铁精矿 H?gan?s工艺 高纯还原铁粉 粉末冶金 磷酸铁锂 

分 类 号：TF55[冶金工程—钢铁冶金]