Factor analysis on the purity of magnesium titanate directly prepared from seashore titanomagnetite concentrate through direct reduction

Abstract

Magnesium titanate was prepared directly through external coal reduction of seashore titanomagnetite concentrate and magnesium oxide (MgO). The effects of roasting temperature and the type and dosage of reductants on the purity of generated magnesium titanate particles were systematically investigated. Scanning electron microscopy and energy-dispersive spectroscopy analyses were performed to characterize the magnesium titanate particles and observe their purity under different conditions. Results showed that the roasting temperature remarkably influenced the purity of magnesium titanate. At 1200, 1300, and 1400°C, some magnesium ferrite and magnesium aluminate spinel were dissolved in magnesium titanate. However, as the roasting temperature increased to 1500°C, relatively pure magnesium titanate particles were generated because no magnesium ferrite was dissolved in them. The type and dosage of the reductants also remarkably affected the purity of magnesium titanate. The amount of fine metallic iron disseminated in the magnesium titanate particles obviously decreased when lignite was used as a reductant at a dosage of 70wt%. Thus, high-purity magnesium titanate particles formed. At a roasting temperature of 1500°C and with 70wt% lignite, the magnesium titanate product with a yield of 30.63% and an iron content of 3.01wt% was obtained through magnetic separation.

Keywords

seashore titanomagnetite / magnesium oxide / direct reduction / magnesium titanate

References

[1] Kang HM, Wang LQ, Xue DF, Li KY, Liu CH. Synthesis of tetragonal flake-like magnesium titanate nanocrystallites. J. Alloys Compd., 2008, 460(1–2): 160.

[2] Apostol I, Saravanan KV, Monty CJA, Vilarinho PM. Solar physical vapor deposition: A new approach for preparing magnesium titanate nanopowders. Appl. Surf. Sci., 2013, 285, 49.

[3] Deng YF, Tang SD, Lao LQ, Zhan SZ. Synthesis of magnesium titanate nanocrystallites from a cheap and water-soluble single source precursor. Inorg. Chim. Acta, 2010, 363(4): 827.

[4] Shanker V, Kumar S, Surendar T. Dielectric behaviour of sodium and potassium doped magnesium titanate. Bull. Mater. Sci., 2012, 35(7): 1165.

[5] Liu YR, Zhang JL, Liu ZJ, Xing XD. Phase transformation behavior of titanium during carbothermic reduction of titanomagnetite ironsand. Int. J. Miner. Metall. Mater., 2016, 23(7): 760.

[6] Sun HY, Adetoro AA, Wang Z, Pan F, Li L. Direct reduction behaviors of titanomagnetite ore by carbon monoxide in fluidized bed. ISIJ Int., 2016, 56(6): 936.

[7] Geng C. The Technology and Mechanism of Direct Reduction Magnetic Separation of Titanium and Iron by the Embedding Method for Seashores Titanomagnetite, 2017, Beijing, University of Science and Technology Beijing [Dissertation]

[8] Yuan S, Zhou WT, Han YX, Li YJ. Efficient enrichment of low-grade refractory rhodochrosite by peeconcenfration-neutral suspension roasting-magnetic separation process. Powder Technol., 2020, 361, 529.

[9] Wang YY, Yang HF, Jiang B, Song RL, Zhang WH. Comprehensive recovery of lead, zinc, and iron from hazardous jarosite residues using direct reduction followed by magnetic separation. Int. J. Miner. Metall. Mater., 2018, 25(2): 123.

[10] Wang XP, Sun TC, Kou J, Li ZC, Tian Y. Feasibility of co-reduction roasting of a saprolitic laterite ore and waste red mud. Int. J. Miner. Metall. Mater., 2018, 25(6): 591.

[11] Wang XP, Sun TC, Chen C, Kou J. Effects of Na₂SO₄ on iron and nickel reduction in a high-iron and low-nickel laterite ore. Int. J. Miner. Metall. Mater., 2018, 25(4): 383.

[12] Wang LW, Lü XM, Liu M, You ZX, Lü XW, Bai CG. Preparation of ferronickel from nickel laterite via coal-based reduction followed by magnetic separation. Int. J. Miner. Metall. Mater., 2018, 25(7): 744.

[13] Gao EX, Sun TC, Liu ZG, Geng C, Xu CY. Effect of sodium sulfate on direct reduction of beach titanomagnetite for separation of iron and titanium. J. Iron Steel Res. Int., 2016, 23(5): 428.

[14] Geng C, Sun TC, Ma YW, Xu CY, Yang HF. Effects of embedding direct reduction followed by magnetic separation on recovering titanium and iron of beach titanomagnetite concentrate. J. Iron Steel Res. Int., 2017, 24(2): 156.

[15] Geng C, Sun TC, Yang HF, Ma YW, Gao EX, Xu CY. Effect of Na₂SO₄ on the embedding direct reduction of beach titanomagnetite and the separation of titanium and iron by magnetic separation. ISIJ Int., 2015, 55(12): 2543.

[16] 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.

[17] Chen C, Sun TC, Wang XP, Hu TY. Effects of MgO on the reduction of vanadium titanomagnetite concentrates with char. JOM, 2017, 69(10): 1759.

[18] Ma YW. Study on Preparing Metallic Iron and Magnesium Titanate from Seaside Titanomagnetite by Direct Reduction Roasting and Magnetic Separation, 2016, Beijing, University of Science and Technology Beijing [Dissertation]

[19] Feng C, Chu MS, Tang J, Liu ZG. Effects of smelting parameters on the slag/metal separation behaviors of Hongge vanadium-bearing titanomagnetite metallized pellets obtained from the gas-based direct reduction process. Int. J. Miner. Metall. Mater., 2018, 25(6): 609.

[20] Geng C, Sun TC, Yang HF, Ma YW, Hu TY. Effect of additives on titanium and iron separation from beach titano-magnetite by direct reduction followed by magnetic separation. Chin. J. Nonferrous Met., 2017, 27(8): 1720.

[21] Shen N. Thermal Annlysis of Magnesium Ferrite Synthetic Process, 2006, Anshan, University of Science and Technology Liaoning [Dissertation]