Correlation between aggregation structure and tailing mineral crystallinity

Abstract

Direct reduction is an emerging technology for the utilization of refractory iron ore. With this technology, iron oxides in the ore can be reduced to recoverable elemental iron. The structure of granular aggregates in direct reduction products was investigated by X-ray diffraction (XRD). The results show that iron is mainly generated as a shell in the outer edge of the aggregates. The thermal conductivity of the iron shell is higher than that of other minerals. Thus, minerals close to the iron shell cool faster than those in the inner shells and do not crystallize well. These minerals mainly become stage 2 tailings. Hence the XRD intensity of stage 2 tailings is lower than that of stage 1 tailings. When iron is mainly generated in the interior of the aggregates, the crystallinity of stage 2 tailings will be higher than that of stage 1 tailings. This indicates that the crystallinity of tailings can be used as a marker for the aggregate structure.

Keywords

iron ore reduction / aggregation / crystallinity / tailings

References

[1] 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.

[2] He Y, Wang HJ, Sun TC, Hu WT, Li HJ. The function and mechanism of an aidant reducer in the deep reduction process of iron ore. J. Harbin Eng. Univ., 2011, 32(12): 1630

[3] Hu WT, Wang HJ, Sun CY, Tong GK, Ji CL, Wang CL. Direct reduction-leaching process for high ferric bauxite. J. Univ. Sci. Technol. Beijing, 2012, 34(5): 506

[4] Hu WT, Wang HJ, Sun CY, Ji CL, He Y, Wang CL. Alkali consumption mechanism on ferrous bauxite reduction process. J. Cent. South Univ. Nat. Sci., 2012, 43(5): 1595

[5] Li KQ, Ni W, Zhu M, Zheng MJ, Li Y. Iron extraction from oolitic iron ore by a deep reduction process. J. Iron Steel Res. Int., 2011, 18(8): 9.

[6] Yeh CH, Zhang GQ. Stepwise carbothermal reduction of bauxite ores. Int. J. Miner. Process., 2013, 124, 1.

[7] Hu WT, Wang HJ, Ji CL, Sun CY, Yu HD, Zhang YH. Selective enrichment of ferric bauxite based on direct-reduction process. J. Cent. South Univ. Nat. Sci., 2012, 43(10): 3755

[8] Hu WT, Wang HJ, Liu XW, Sun CY. Effect of nonmetallic additives on iron grain grindability. Int. J. Miner. Process., 2014, 130, 108.

[9] Zhu DQ, Chun TJ, Pan J, He Z. Recovery of iron from high-iron red mud by reduction roasting with adding sodium salt. J. Iron Steel Res. Int., 2012, 19(8): 1.

[10] Hu WT, Wang HJ, Liu XW, Wang B. Monomer dissociation characteristics and selective recovery technology of micro-fine iron particles. J. Univ. Sci. Technol. Beijing, 2013, 35(11): 1424

[11] Mei XG, Yuan ML, Zuo WL, Chen J. Studies on the nucleation and grain growth characteristics of metallic phase in direct reduction of high-iron red mud with coal base. J. Cent. South Inst. Min. Metall., 1994, 25(6): 696

[12] Mei XG, Yuan ML, Zuo WL, Chen J. Kinetics of the nucleation and grain growth of metallic phase in direct reduction of high-iron red mud with coal base. J. Cent. South Univ. Nat. Sci., 1996, 27(2): 159

[13] Zhu DQ, Chun TJ, Pan J. Mechanism of action of improving reduction on low grade hematite pellets by adding nucleating agent. J. Univ. Sci. Technol. Beijing, 2011, 33(11): 1325

[14] Hu WT, Wang HJ, Sun CY, Yu HD. Formation progress and metallographic structure of iron grain aggregates in reduction-sintering system. J. Cent. South Univ. Nat. Sci., 2013, 44(10): 3971

[15] Ogawa M, Morita M, Igarashi S, Sato S. A green synthesis of a layered titanate, potassium lithium titanate; lower temperature solid-state reaction and improved materials performance. J. Solid State Chem., 2013, 206, 9.

[16] Bastami TR, Entezari MH. Sono-synthesis of Mn3O4 nanoparticles in different media without additives. Chem. Eng. J., 2010, 164(1): 261.

[17] Montes-Hernandez G, Renard F, Chiriac R, Findling N, Ghanbaja J, Toche F. Sequential precipitation of a new goethite-calcite nanocomposite and its possible application in the removal of toxic ions from polluted water. Chem. Eng. J., 2013, 214, 139.

[18] Liu XW, Feng YL, Li HR, Yang ZC, Cai ZL. Recovery of valuable metals from a low-grade nickel ore using an ammonium sulfate roasting-leaching process. Int. J. Miner. Metall. Mater., 2012, 19(5): 377.

[19] Fulkerson W, Moore JP, McElroy DL. Comparison of the thermal conductivity, electrical resistivity, and Seebeck coefficient of a high-purity iron and an Armco iron to 1000°C. J. Appl. Phys., 1966, 37, 2639.

[20] Manga M, Jeanloz R. Thermal conductivity of corundum and periclase and implications for the lower mantle. J. Geophys. Res. Solid Earth, 1997, 102(B2): 2999.