Some basic properties of granules from ore blends consisting of ultrafine magnetite and hematite ores

Abstract

Some basic properties of granules, including the granule size distribution, packed-bed permeability, and chemical composition of the adhering layer, were investigated in this study for four iron ore blends consisting of 5wt%, 25wt%, and 45wt% ultrafine magnetite and 25wt% ultrafine hematite concentrates. The effects of varying the sinter basicity (CaO/SiO₂ mass ratio = 1.4 to 2.2) and adding ultrafine concentrates on the variation of the adhering-layer composition and granule microstructure were studied. Moreover, the effect of adhering-layer compositional changes on sintering reactions was discussed in combination with pot sintering results of ore blends. Increasing sinter basicity led to an increase in the basicities of both the adhering layer and the fine part of the sinter mix, which were higher than the overall sinter basicity. When the sinter chemistry was fixed and fine Si-bearing materials (e.g., quartz sand) were used, increasing the amount of ultrafine ores in the ore blends tended to reduce the adhering-layer basicity and increase the SiO₂ content in both the adhering layer and the fine part of the sinter mix, which will induce the formation of low-strength bonding phases and the deterioration of sinter strength. The adhering-layer composition in granules can be estimated in advance from the compositions of the −1 mm fractions of the raw materials.

Keywords

iron ore / granule / adhering layer / magnetite / concentrate / sinter / basicity

References

[1] Roller PW. Granulation of iron ores. BHP Tech. Bull., 1982, 26, 44.

[2] Kasai E, Rankin WJ, Gannon JF. The effect of raw mixture properties on bed permeability during sintering. ISIJ Int., 1989, 29(1): 33.

[3] Formoso A, Moro A, Fernández Pello G, Menéndez JL, Muñiz M, Cores A. Influence of nature and particle size distribution on granulation of iron ore mixtures used in a sinter strand. Ironmaking Steelmaking, 2003, 30(6): 447.

[4] Jeon JW, Kim SW, Suh IK, Jung SM. Assimilation behavior of quasi-particle comprising high alumina pisolitic ore. ISIJ Int., 2014, 54(12): 2713.

[5] Haga T, Ohshio A, Nakamura K, Kozono T, Uekawa K. Control technique of the melting reaction in sintering process by the fine part selective granulation of clayish iron ores. Tetsu-to-Hagané, 1997, 83(2): 103.

[6] Wu SL, Zhu J, Bei JC, Zhang GL, Zhai XB. Effects of particle characteristics on the granulation ability of iron ores during the sintering process. Int. J. Miner. Metall. Mater, 2015, 22(9): 907.

[7] Zhang F, Zhu DQ, Pan J, Mo YP, Guo ZQ. Improving the sintering performance of blends containing Canadian specularite concentrate by modifying the binding medium. Int. J. Miner. Metall. Mater., 2018, 25(6): 598.

[8] A. Sakai, H. Noda, H. Sato, M. Shiobara, K.Hashimoto, and K. Yamashita, Technological improvements to attain high productivity at Fukuyama No. 5 sintering machine (HPS), [in] NKK Technical Report, Japanese edition, 2001, p. 34.

[9] Jiang T, Li GH, Wang HT, Zhang KC, Zhang YB. Composite agglomeration process (CAP) for preparing blast furnace burden. Ironmaking Steelmaking, 2010, 37(1): 1.

[10] Pan J, Shi BJ, Zhu DQ, Mo YP. Improving sintering performance of specularite concentrates by pre-briquetting process. ISIJ Int., 2016, 56(5): 777.

[11] Wu S, Sugiyama T, Morioka K, Kasai E, Omori Y. Elimination reaction of NO gas generated from coke combustion in iron ore sinter bed. Tetsu-to-Hagané, 1994, 80(4): 276.

[12] Katayama K, Kasama SJ. Influence of lime coating coke on NO_x concentration in sintering process. ISIJ Int., 2016, 56(9): 1563.

[13] Gan M, Fan XH, Lü W, Chen XL, Ji ZY, Jiang T, Yu ZY, Zhou Y. Fuel pre-granulation for reducing NO_x emission from the iron ore sintering process. Powder Technol., 2016, 301, 478.

[14] Zhou H, Liu ZH, Cheng M, Zhou MX, Liu RP. Influence of coke combustion on NOx emission during iron ore sintering. Energy Fuels, 2015, 29(2): 974.

[15] Loo CE, Leung W. Factors influencing the bonding phase structure of iron ore sinters. ISIJ Int., 2003, 43(9): 1393.

[16] Lu LM, Holmes RJ. Effects of alumina on sintering performance of hematite iron ores. ISIJ Int., 2007, 47(3): 349.

[17] Okazaki J, Higuchi K. Marra Mamba ore, its mineralogical properties and evaluation for utilization. ISIJ Int., 2005, 45(4): 427.

[18] Han HL, Lu LM. Recent advances in sintering with high proportions of magnetite concentrates. Miner. Process. Extr. Metall. Rev, 2018, 39(4): 217.

[19] Yang CC, Zhu DQ, Shi BJ, Pan J, Lu LM, Li XB, Mo YP. Comparison of sintering performance of typical specular hematite ores with distinct size distributions. J. Iron Steel Res. Int., 2017, 24(10): 1007.

[20] Yang LX. Sintering fundamentals of magnetite alone and blended with hematite/goethite ores. ISIJ Int., 2005, 45(4): 469.

[21] Jeon JW, Kim SW, Jung SM. Utilization of magnetite concentrate as an additive in adhering fines of quasi-particle and its effect on assimilation behavior. ISIJ Int., 2015, 55(3): 513.

[22] Yang CC, Zhu DQ, Pan J, Lu LM. Granulation effectiveness of iron ore sinter feeds: Effect of ore properties. ISIJ Int., 2018, 58(8): 1427.

[23] Lu LM. Important iron ore characteristics and their impacts on sinter quality—a review. Miner. Metall. Process., 2015, 32(2): 88.

[24] Pownceby MI, Clout JMF. Phase relations in the Fe-rich part of the system Fe₂O₃ (-Fe₃O₄)-CaO-SiO₂ at 1240–1300°C and oxygen partial pressure of 5×10⁻³ atm: implications of iron ore sinter. Miner. Process. Extr. Metall., 2000, 109(1): 36.

[25] Webster NAS, Pownceby MI, Madsen IC, Studer AJ, Manuel JR, Kimpton JA. Fundamentals of silico-ferrite of calcium and aluminum (SFCA) and SFCA-I iron ore sinter bonding phase formation: effects of CaO:SiO₂ ratio. Metall. Mater. Trans. B, 2014, 45(6): 2097.

[26] Rankin WJ, Roller PW, Batterham RJ. Analysis of the permeability of granulated iron ore sinter feeds using the Ergun equation. Miner. Metall. Process., 1985, 2(1): 53.

[27] Hinkley J, Waters AG, Litster JD. An investigation of pre-ignition air flow in ferrous sintering. Int. J. Miner. Process., 1994, 41(1–2): 37.

[28] Ellis BG, Loo CE, Witchard D. Effect of ore properties on sinter bed permeability and strength. Ironmaking Steelmaking, 2007, 34(2): 99.

[29] Pownceby MI, Clout JMF. Importance of fine ore chemical composition and high temperature phase relations: applications to iron ore sintering and pelletising. Miner. Process. Extr. Metall., 2003, 112(1): 44.

[30] Kasai E, Wu SL, Omori Y. Factors governing the strength of agglomerated granules after sintering. ISIJ Int., 1991, 31(1): 17.

[31] Clout JMF, Manuel JR. Fundamental investigations of difference in bonding mechanisms in iron ore sinter formed from magnetite concentrates and hematite ores. Powder Technol., 2003, 130(1–3): 393.

[32] Zhang GL, Wu SL, Su B, Que ZG, Hou CG, Jiang Y. Influencing factor of sinter body strength and its effects on iron ore sintering indexes. Int. J. Miner. Metall. Mater., 2015, 22(6): 553.

[33] Tang XR. Theory and Technology of Iron Ore Sintering, 1992, Changsha, Central South University Press 186.

[34] Ying ZW, Jiang MF, Xu LX. Effects of mineral composition and microstructure on crack resistance of sintered ore. J. Iron Steel Res. Int., 2006, 13(4): 9.

[35] Wei Q, Mao XM, Shen HB. Study on properties of sinter mineral phases. Baosteel Tech. Res., 2018, 12(3): 16.

[36] Shigaki I, Sawada M, Tsuchiya O, Yoshioka K, Takahashi T. Study of primary melt formation and transition mechanism to final slag of sintered ore. Tetsu-to-Hagané, 1984, 70(16): 2208.

[37] Matsuno F. Changes of mineral phases during the sintering of Fe₂O₃-CaO-SiO₂ system. Tetsu-to-Hagané, 1978, 64(10): 1499.

[38] Matsuno F, Harada T. Changes of mineral phases during the sintering of iron ore-lime stone systems. Trans. ISIJ, 1981, 21(5): 318.