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

Abstract

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/cm³, 9.01 s/(50 g) and 6.55 g/cm³, 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.

Keywords

reverse flotation / ultra-pure magnetite concentrate / Höganäs process / high-purity reduced iron powder / powder metallurgy / lithium iron phosphate

References

[1] OrbanR. New research directions in powder metallurgy [J]. Romanian Reports in Physics, 2004, 56(3): 557-570

[2] YangT. Production and development of powder metallurgy iron powders [J]. World Metal Herald, 2016, 5: 46-57(in Chinese)

[3] BlancoL, CamposM, TorralbaJ M, et al. . Quantitative evaluation of porosity effects in sintered and heat treated high performance steels [J]. Powder Metallurgy, 2005, 48(4): 315-322

[4] GuoZ-Q, ZhuD-Q, PanJ, et al. . Efficient and green treatment of ultrapure magnetite to prepare powder metallurgy iron powders [J]. Powder Technology, 2021, 378: 19-28

[5] ArulmaniL, ShridharmurthyH N, SelvanM C P, et al. . Hot Powder forging behavior analysis of sintered AISI 8740 PM steels for automotive application [J]. Materials Today: Proceedings, 2020, 28: 1068-1072

[6] LiuY, NiuS, LiF, et al. . Preparation of amorphous Fe-based magnetic powder by water atomization [J]. Powder Technology, 2011, 213(1–3): 36-40

[7] AkimenkoV B, GulyaevI A, SekachevM A, et al. . Air-atomized iron powders—Past, present, future [J]. Metallurgist, 2007, 51(11): 624-630

[8] HeW-C, LvX-W, PanF-F, et al. . Novel preparation process of iron powders with semisteel by rotary cup atomizer [J]. Powder Technology, 2019, 356: 1087-1096

[9] HeW-C, LvX-W, PanF-F, et al. . Preparation of iron powders using rotary cup atomizer with water curtain [J]. Powder Technology, 2020, 364: 300-309

[10] YuX. Sponge iron and reduced iron powder produced by Höganäs process [J]. Powder Metal Indust, 1997, 7: 31-39

[11] BelovaI I, FimushkinaN N, PospekhovaÉ N, et al. . Advantages of using water-atomized iron powders [J]. Metallurgist, 1988, 32(4): 146-148

[12] PasupathyM, MartínJ M, RivasA, et al. . Effect of the solidification time on the median particle size of powders produced by water atomisation [J]. Powder Metallurgy, 2016, 59(2): 128-141

[13] LiS-L, YangQ-M, CuiJ-M, et al. . Effects of major impurity elements on compressibility of water-atomized iron powder [J]. Powder Metallurgy and Metal Ceramics, 2012, 51(3): 142-149

[14] HanF-L. Production of atomized iron and steel powders at QMP Co [J]. Powder Metallurgy Industry, 2003, 13(2): 16-21(in Chinese)

[15] YaoG-Z, LiY-L, GuoQ, et al. . Preparation of reduced iron powder for powder metallurgy from magnetite concentrate by direct reduction and wet magnetic separation [J]. Powder Technology, 2021, 392: 344-355

[16] LippmannH, MannlV, BontchevaN, et al. . Numerical simulation of density distribution during compaction of iron powders [J]. Archive of Applied Mechanics, 1997, 67(3): 191-199

[17] MoriokaY. Recent trends in powder metallurgy industry and technology [J]. Journal of the Japan Society of Powder and Powder Metallurgy, 1993, 40(8): 755-762

[18] NemanovaV, NordgreenT, EngvallK, et al. . Biomass gasification in an atmospheric fluidised bed: Tar reduction with experimental iron-based granules from Höganäs AB, Sweden [J]. Catalysis Today, 2011, 176(1): 253-257

[19] BenchiheubO, MechachtiS, SerraiS, et al. . Elaboration of iron powder from mill scale [J]. J Mater Environ Sci, 2010, 1: 267-276

[20] YeQ-X, ZhuH-B, PengJ-H, et al. . Preparation of reduced iron powders from mill scale with microwave heating: Optimization using response surface methodology [J]. Metallurgical and Materials Transactions B, 2013, 44(6): 1478-1485

[21] ZhuY-B, TanC-B, ChenS-W. Production of reduced iron powder using ultra-fine iron concentrate [J]. Journal of Wuhan University of Technology-Mater Sci Ed, 2003, 18(3): 97-98

[22] MartínM I, LópezF A, TorralbaJ M. Production of sponge iron powder by reduction of rolling mill scale [J]. Ironmaking & Steelmaking, 2012, 39(3): 155-162

[23] BagatiniM C, FernandesT, SilvaR, et al. . Mill scale and flue dust briquettes as alternative burden to low height blast furnaces [J]. Journal of Cleaner Production, 2020, 276: 124332

[24] JikarP C, DhokeyN B. Overview on production of reduced iron powder from mill scale waste [J]. Materials Today: Proceedings, 2021, 444324-4329

[25] UmadeviT, Sampath KumarM G, MahapatraP C, et al. . Recycling of steel plant mill scale via iron ore pelletisation process [J]. Ironmaking & Steelmaking, 2009, 36(6): 409-415

[26] ChoY I, KimB H, KimS J, et al. . Preparation and characterization of zero valent iron powders via transfer type reductor using iron oxide from the acid regeneration process [J]. Advanced Powder Technology, 2013, 24(5): 858-863

[27] LiF, ZhaoQ-J, ChuM-S, et al. . Preparing high-purity iron by direct reduction-smelting separation of ultra-high-grade iron concentrate [J]. International Journal of Minerals, Metallurgy and Materials, 2020, 27(4): 454-462

[28] WuJ-T, XuB, ZhouY-J, et al. . A novel process of reverse flotation-hydrogen reduction for preparation of high-purity iron powder with superior magnetite concentrate [J]. Separation and Purification Technology, 2023, 307122784

[29] SAITO S, SONOBE A, OGURA K. Characteristics of high compressibility atomized iron powder with improved compactability [J]. Advances in Powder Metallurgy, 1991(5): 105–117.

[30] STEPHEN F C. The origins of high compressibility in water atomized iron powder [J]. Advances in Powder Metallurgy, 1996(1): 125–138.

[31] LeeD J, YoonE Y, KimH N, et al. . Effect of particle size on compactibility of water-atomized pure iron powder [J]. Journal of Korean Powder Metallurgy Institute, 2011, 18(3): 221-225

[32] TallonP G, MalakhovD V. Properties of a powder metallurgy low-alloy steel with varying fractions of large iron particles [J]. Canadian Metallurgical Quarterly, 2021, 60(4): 249-264

[33] HuangH-BPreparation and compressibility of high purity electrolytic iron powder [D], 2018, Wuhan, China, Wuhan University of Science and Technology(in Chinese)

[34] YangQ-MResearch on the processing properties of water-atomized iron powder [D], 2012, Changsha, China, Central South University(in Chinese)

[35] WuJ-TPreparation of high purity reduced iron powder from high-quality magnetite concentrate by reverse flotation-hydrogen reduction of low carbon [D], 2022, Changsha, China, Central South University(in Chinese)

[36] YanX-CStudy on technology and mechanism of preparing powder metallurgical iron powder from ultra pure magnetite concentrate [D], 2019, Changsha, China, Central South University(in Chinese)