Reduction behavior of hematite in the presence of coke

Abstract

The reduction kinetics of hematite in the presence of coke as a reductant was studied via isothermal and non-isothermal thermodynamic analyses. The isothermal reduction of hematite was conducted at a pre-determined temperature ranging from 1423 to 1573 K. The results indicated that a higher reduction temperature led to an increased reduction degree and an increased reduction rate. The non-isothermal reduction of hematite was carried out from room temperature to 1573 K at various heating rates from 5 to 15 K·min⁻¹. A greater heating rate gave a greater reduction rate but decreased reduction degree. With an increase in temperature, both the reduction rate and the reduction degree increased at a smaller rate when the temperature was less than 1150 K, and they increased at a higher rate when the temperature was greater than 1150 K before completion of the reduction reaction. Both the isothermal and the non-isothermal reduction behaviors of hematite were described by the Avrami–Erofeev model. For the isothermal reduction, the apparent activation energy and pre-exponential factor were 171.25 kJ·mol⁻¹ and 1.80 × 10⁵ min⁻¹, respectively. In the case of non-isothermal reduction, however, the apparent activation energy and pre-exponential factor were correlated with the heating rate.

Keywords

hematite / ore reduction / reduction kinetics / coke

References

[1] Gao P., Sun Y.S., Ren D.Z., Han Y.X. Growth of metallic iron particles during coal-based reduction of a rare earths-bearing iron ore. Miner. Metall. Process., 2013, 30(1): 74.

[2] Li Y.J., Sun Y.S., Han Y.X., Gao P. Coal-based reduction mechanism of low-grade laterite ore. Trans. Nonferrous Met. Soc. China, 2013, 23(11): 3428.

[3] Özdemir Deutsch E.R. Magnetic properties of oolitic iron ore on Bell Island, Newfoundland. Earth Planet. Sci. Lett., 1984, 69(2): 427.

[4] Zimmels Y., Weissberger S., Lin I.J. Effect of oolite structure on direct reduction of oolitic iron ores. Int. J. Miner. Process., 1988, 24(1-2): 55.

[5] Tang H.Q., Guo Z.C., Zhao Z.L. Phosphorus removal of high phosphorus iron ore by gas-based reduction and melt separation. J. Iron Steel Res. Int., 2010, 17(9): 1.

[6] Nunes A.P.L., Pinto C.L.L., Valadão G.E.S., Viana P.R.D.M. Floatability studies of wavellite and preliminary results on phosphorus removal from a Brazilian iron ore by froth flotation. Miner. Eng., 2012, 39(12): 206.

[7] Manieh A.A. Oolite liberation of oolitic iron ore, Wadi Fatima, Saudi Arabia. Int. J. Miner. Process., 1984, 13(3): 187.

[8] Li G.H., Zhang S.H., Rao M.J., Zhang Y.B., 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.

[9] Li G.F., Han Y.X., Gao P., Sun Y.S. Enrichment of phosphorus in reduced iron during coal-based reduction of a high phosphorus-containing oolitic hematite ore. Ironmaking Steelmaking, 2016, 43(3): 163.

[10] Xu C.Y., Sun T.C., Kou J., Li Y.L., Mo X.L., Tang L.G. Mechanism of phosphorus removal in beneficiation of high phosphorous oolitic hematite by direct reduction roasting with dephosphorization agent. Trans. Nonferrous Met. Soc. China, 2012, 22(11): 2806.

[11] Gao P., Li G.F., Han Y.X., Sun Y.S. Reaction behavior of phosphorus in coal-based reduction of an oolitic hematite ore and pre-dephosphorization of reduced iron. Metals, 2016, 6(4): 82.

[12] Yu Y.F., Qi C.Y. Magnetizing roasting mechanism and effective ore dressing process for oolitic hematite ore. J. Wuhan Univ. Technol. Mater. Sci. Ed., 2011, 26(2): 176.

[13] Sun Y.S., Han Y.X., Gao P., Wang Z.H., Ren D.Z. Recovery of iron from high phosphorus oolitic iron ore using coal-based reduction followed by magnetic separation. Int. J. Miner. Metall. Mater., 2013, 20(5): 411.

[14] Li Y.L., Sun T.C., Zou A.H., Xu C.Y. Effect of coal levels during direct reduction roasting of high phosphorus oolitic hematite ore in a tunnel kiln. Int. J. Min. Sci. Technol., 2012, 22(3): 323.

[15] Sun Y.S., Gao P., Han Y.X., Ren D.Z. Reaction behavior of iron minerals and metallic iron particles growth in coal-based reduction of an oolitic iron ore. Ind. Eng. Chem. Res., 2013, 52(6): 2323.

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

[17] Zuo H.B., Wang C., Dong J.J., Jiao K.X., Xu R.S. Reduction kinetics of iron oxide pellets with H₂ and CO mixtures. Int. J. Miner. Metall. Mater., 2015, 22(7): 688.

[18] Mondal K., Lorethova H., Hippo E., Wiltowski T., Lalvani S.B. Reduction of iron oxide in carbon monoxide atmosphere- reaction controlled kinetics. Fuel Process. Technol., 2004, 86(1): 33.

[19] Hou B.L., Zhang H.Y., Li H.Z., Zhu Q.S. Study on kinetics of iron oxide reduction by hydrogen. Chin. J. Chem. Eng., 2012, 20(1): 10.

[20] Wei R.F., Cang D.Q., Zhang L.L., Bai Y.Y. Staged reaction kinetics and characteristics of iron oxide direct reduction by carbon. Int. J. Miner. Metall. Mater., 2015, 22(10): 1025.

[21] Shabbar S., Janajreh I. Thermodynamic equilibrium analysis of coal gasification using Gibbs energy minimization method. Energy Convers. Manage., 2013, 65, 755.

[22] Hu T., Lü X.W., Bai C.G., Qiu G.B. Isothermal reduction of titanomagnetite concentrates containing coal. Int. J. Miner. Metall. Mater., 2014, 21(2): 131.

[23] Wiltowski T., Hinckley C.C., Smith G.V., Nishizawa T., Saproschenko M., Shiley R.H., Webster J. R. Kinetics and mechanisms of iron sulfide reductions in hydrogen and in carbon monoxide. J. Solid State Chem., 1987, 71(1): 95.

[24] Tanaka H. Thermal analysis and kinetics of solid state reactions. Thermochim. Acta, 1995, 267, 29.

[25] Vyazovkin S., Burnham A.K., Criado J.M., Pérez-Maqueda L.A., Popescu C., Sbirrazzuoli N. ICTAC Kinetics Committee recommendations for performing kinetic computations on thermal analysis data. Thermochim. Acta, 2011, 520(1-2): 1.

[26] Škvára F., Šesták J. Computer calculation of the mechanism and associated kinetic data using a non-isothermal integral method. J. Them. Anal., 1975, 8(3): 477.

[27] Sun Y.S., Han Y.X., Wei X.C., Gao P. Non-isothermal reduction kinetics of oolitic iron ore in ore/coal mixture. J. Therm. Anal. Calorim., 2016, 123(1): 703.

[28] Lin Q., Chen N., Ye W., Liu R.M. Kinetics of direct reduction for chrome iron ore. Mod. Sci. Instrum., 1998 29.

[29] Zhao S.P., Jiang J.C. Thermal analysis hydrodynamics study on FeS. J. China Univ. Pet., 2010, 34(5): 164.

[30] Sun K., Zhang X.F. Reduction kinetics of Panzhihua ilmenite. Iron Steel Vanadium Titanium, 1996, 17(3): 19.

[31] Zou J.H., Zhou Z.J., Wang F.C., Zhang W., Dai Z.H., Liu H.F., Yu Z.H. Modeling reaction kinetics of petroleum coke gasification with CO₂. Chem. Eng. Process., 2007, 46(7): 630.