Effect of additives on iron recovery and dephosphorization by reduction roasting-magnetic separation of refractory high-phosphorus iron ore

Abstract

The effect of CaCO₃, Na₂CO₃, and CaF₂ on the reduction roasting and magnetic separation of high-phosphorus iron ore containing phosphorus in the form of Fe₃PO₇ and apatite was investigated. The results revealed that Na₂CO₃ had the most significant effect on iron recovery and dephosphorization, followed by CaCO₃, the effect of CaF₂ was negligible. The mechanisms of CaCO₃, Na₂CO₃, and CaF₂ were investigated using X-ray diffraction (XRD), scanning electron microscopy and energy dispersive spectrometry (SEM-EDS). Without additives, Fe₃PO₇ was reduced to elemental phosphorus and formed an iron-phosphorus alloy with metallic iron. The addition of CaCO₃ reacted with Fe₃PO₇ to generate an enormous amount of Ca₃(PO₄)₂ and promoted the reduction of iron oxides. However, the growth of iron particles was inhibited. With the addition of Na₂CO₃, the phosphorus in Fe₃PO₇ migrated to nepheline and Na₂CO₃ improved the reduction of iron oxides and growth of iron particles. Therefore, the recovery of iron and the separation of iron and phosphorus were the best. In contrast, CaF₂ reacted with Fe₃PO₇ to form fine Ca₃(PO₄)₂ particles scattered around the iron particles, making the separation of iron and phosphorus difficult.

Keywords

high-phosphorus iron ore / additives / reduction roasting / magnetic separation / iron recovery / dephosphorization

References

[1] Li XH, Kou J, Sun TC, Wu SC, Zhao YQ. Effects of calcium compounds on the carbothermic reduction of vanadium titanomagnetite concentrate. Int. J. Miner. Metall. Mater., 2020, 27(3): 301.

[2] Li XH, Kou J, Sun TC, Wu SC, Zhao YQ. Formation of calcium titanate in the carbothermic reduction of vanadium titanomagnetite concentrate by adding CaCO₃. Int. J. Miner. Metall. Mater., 2020, 27(6): 745.

[3] Tang ZD, Gao P, Sun YS, Han YX, Li EL, Chen J, Zhang YH. Studies on the fluidization performance of a novel fluidized bed reactor for iron ore suspension roasting. Powder Technol., 2020, 360, 649.

[4] Tang J, Chu MS, Li F, Feng C, Liu ZG, Zhou YS. Development and progress on hydrogen metallurgy. Int. J. Miner. Metall. Mater., 2020, 27(6): 713.

[5] Zhao YQ, Sun TC, Zhao HY, Chen C, Wang XP. Effect of reductant type on the embedding direct reduction of beach titanomagnetite concentrate. Int. J. Miner. Metall. Mater., 2019, 26(2): 152.

[6] Ionkov K, Gaydardzhiev S, Correa de Araujo A, Bastin D, Lacoste M. Amenability for processing of oolitic iron ore concentrate for phosphorus removal. Miner. Eng., 2013, 47, 119.

[7] McGregor F, Ramanaidou E, Wells M. Phanerozoic ooidal ironstone deposits—Generation of potential exploration targets. Appl. Earth Sci., 2010, 119(1): 60.

[8] Omran M, Fabritius T, Mattila R. Thermally assisted liberation of high phosphorus oolitic iron ore: A comparison between microwave and conventional furnaces. Powder Technol., 2015, 269, 7.

[9] Nunes APL, Pinto CLL, Valadão GES, Viana PRDM. Floatability studies of wavellite and preliminary results on phosphorus removal from a Brazilian iron ore by froth flotation. Miner. Eng., 2012, 39, 206.

[10] Bao QP, Guo L, Guo ZC. A novel direct reduction-flash smelting separation process of treating high phosphorous iron ore fines. Powder Technol., 2021, 377, 149.

[11] Wu SC, Sun TC, Li ZY, Xu CY, Li XH. Research progress of direct reduction-magnetic separation of high phosphorus iron ore. Met. Mine, 2021, 50(2): 58

[12] Quast K. A review on the characterisation and processing of oolitic iron ores. Miner. Eng., 2018, 126, 89.

[13] Khassen B, Baltynova N, Dakhno L. Investigation of dephosphorization of brown iron ore concentrates by sintering and magnetic beneficiation. Int. J. Miner. Process., 2014, 126, 136.

[14] Tang HQ, Qin YQ, Qi TF. Phosphorus removal and iron recovery from high-phosphorus hematite using direct reduction followed by melting separation. Miner. Process. Extr. Metall. Rev., 2016, 37(4): 236.

[15] Yu JT, Guo ZC, Tang HQ. Dephosphorization treatment of high phosphorus oolitic iron ore by hydrometallurgical process and leaching kinetics. ISIJ Int., 2013, 53(12): 2056.

[16] Zhang L, Machiela R, Das P, Zhang MM, Eisele T. Dephosphorization of unroasted oolitic ores through alkaline leaching at low temperature. Hydrometallurgy, 2019, 184, 95.

[17] Zhang HQ, Zhang ZQ, Luo LQ, Yu H. Behavior of Fe and P during reduction magnetic roasting-separation of phosphorus-rich oolitic hematite. Energy Sources A, 2019, 41(1): 47.

[18] Zhou WT, Han YX, Sun YS, Li YJ. Strengthening iron enrichment and dephosphorization of high-phosphorus oolitic hematite using high-temperature pretreatment. Int. J. Miner. Metall. Mater., 2020, 27(4): 443.

[19] Li YL, Sun TC, Kou J, Guo Q, Xu CY. Study on phosphorus removal of high-phosphorus oolitic hematite by coal-based direct reduction and magnetic separation. Miner. Process. Extr. Metall. Rev., 2014, 35(1): 66.

[20] Xu Y, Sun TC, Liu ZG, Xu CY. Phosphorus occurrence state and phosphorus removal research of a high phosphorous oolitic hematite by direct reduction roasting method. J. Northeast. Univ. Nat. Sci., 2013, 34(11): 1651

[21] Li GH, Zhang SH, Rao MJ, Zhang YB, Jiang T. Effects of sodium salts on reduction roasting and Fe-P separation of high-phosphorus oolitic hematite ore. Int. J. Miner. Process., 2013, 124, 26.

[22] Rao MJ, Ouyang CZ, Li GH, Zhang SH, Zhang YB, Jiang T. Behavior of phosphorus during the carbothermic reduction of phosphorus-rich oolitic hematite ore in the presence of Na₂SO₄. Int. J. Miner. Process., 2015, 143, 72.

[23] Yu W, Sun TC, Kou J, Wei YX, Xu CY, Liu ZZ. The function of Ca(OH)₂ and Na₂CO₃ as additive on the reduction of high-phosphorus oolitic hematite-coal mixed pellets. ISIJ Int., 2013, 53(3): 427.

[24] Wu SC, Sun TC, Yang HF. Study on phosphorus removal of high-phosphorus oolitic hematite abroad by direct reduction and magnetic separation. Met. Mine, 2019, 48(11): 109

[25] Cheng CY, Misra VN, Clough J, Muni R. Dephosphorisation of western Australian iron ore by hydrometallurgical process. Miner. Eng., 1999, 12(9): 1083.

[26] Huang WS, Yan L, Wu SC, Sun TC. Study on the process mineralogy of a high phosphorus ooliticiron ore in abroad. Met. Mine, 2020, 49(9): 137

[27] B.Z. Ma, X. Li, W.J. Yang, D. Hu, P. Xing, B. Liu, and C.Y. Wang, Nonmolten state metalized reduction of saprolitic laterite ores: Effective extraction and process optimization of nickel and iron, J. Clean. Prod., 256(2020), art. No. 120415.

[28] Hu TY, Sun TC, Kou J, Geng C, Zhao YQ. Effects and mechanisms of fluorite on the co-reduction of blast furnace dust and seaside titanomagnetite. Int. J. Miner. Metall. Mater., 2017, 24(11): 1201.

[29] Sun YS, Li YF, Wang DZ, Han YX. Thermodynamic analysis of the reduction process of fluorapatite. J. Northeast. Univ. Nat. Sci., 2019, 40(6): 875