2016-Sustainable Industrial Processing Summit
SIPS 2016 Volume 6: Yagi Intl. Symp. / Metals & Alloys Processing

Editors:Kongoli F, Akiyama T, Nogami H, Saito K, Fujibayashi A
Publisher:Flogen Star OUTREACH
Publication Year:2016
Pages:480 pages
ISBN:978-1-987820-46-1
ISSN:2291-1227 (Metals and Materials Processing in a Clean Environment Series)
CD-SIPS2016_Volume1
CD shopping page

    Multistep reduction kinetics of hematite (Fe2O3) to iron in a micro fluidized bed reactor by hydrogen at low temperatures

    Hongsheng Chen1; Zhong Zheng1; Zhiwei Chen2; Xu He1; Kun He3;
    1CHONGQING UNIVERSITY, Chongqing, China; 2UNIVERSITY OF BRITISH COLUMBIA, Vancouver, Canada; 3, Chongqing, China;
    Type of Paper: Regular
    Id Paper: 50
    Topic: 3

    Abstract:

    The production of direct reduced iron (DRI) using hydrogen instead of carbon monoxide helps to reduce CO2 emission and slows down global warming. The reduction of hematite occurs in two-step as Fe2O3-Fe3O4-Fe when temperatures are below 570 .A better understanding of the two-step reduction kinetics of hematite with hydrogen will reveal useful fundamental information for the industrial applications and promotes the development of energy-saving technologies for iron making. The reduction of iron oxides into iron is complex because the process is heterogeneous and several elementary reactions take place simultaneously. It is hard to figure out the reduction kinetics under fluidization in a fixed bed reactor such as in a thermogravimetry analyzer (TGA) which suffers from the limitations of heating rate, external diffusion, thermal pretreatment before a reaction occurs. In this study, the reduction kinetics of hematite to metallic iron with hydrogen at temperature 300-550 are experimentally investigated in a micro-fluidized bed reaction analyzer (MFBRA), developed by the Institute of Process Engineering (IPE), Chinese Academy of Sciences (CAS) to study the kinetics of fast gas-solid reactions. Results indicate that the low-temperature reduction of hematite with hydrogen can be well captured by a two-step kinetics method based on Johnson-Mehl-Avrami (JMA) model using statistical analysis tools in the Statistical Product and Service Solutions (SPSS). It shows that the reduction process can be interpreted as two elementary reactions (i.e. hematite-magnetite and magnetite-iron), which proceed in parallel with different controlling mechanisms as well as with different time dependencies. The kinetics parameters, i.e. activation energy and pre-exponential factor, are determined for each elementary reaction. The contribution of each individual reaction to the whole reduction process is further discussed. The results also suggest that the reduction of hematite to magnetite takes place fast and dominates the initial part of the entire reduction while the reduction of magnetite to iron plays a less important role in the initial stage but controls the whole reduction in the late stage. The conclusions obtained in this study are comparable with that in the literature and indicate that the two-step kinetics model is able to capture the properties of both elementary reactions and the integrated reduction process, providing an analysis strategy for revealing detail characteristics of the low-temperature reduction of iron oxides.

    Keywords:

    Micro fluidized bed; Multistep reduction kinetics; Iron oxide reduction; Hydrogen.

    References:

    [1] D. Guo, L. Zhu, S. Guo, B. Cui, S. Luo, M. Laghari, Z. Chen, C. Ma, Y. Zhou, J. Chen, B. Xiao, M. Hu, S. Luo: Direct reduction of oxidized iron ore pellets using biomass syngas as the reducer, Fuel Processing Technology, 148 (2016), 276-281.
    [2] J.L. Schenk: Recent status of fluidized bed technologies for producing iron input materials for steelmaking, Particuology, 9 (2011), 14-23.
    [3] A. Pineau, N. Kanari, I. Gaballah: Kinerics of reduction of iron oxides by H2 Part I: Low temperature reduction of hematite, Thermochimica Acta, 447 (2006), 89-100.
    [4] L. Barreto, A. Makihira, K. Riahi: The hydrogen economy in the 21st century: a sustainable development scenario, International Journal of Hydrogen Energy, 28 (2003), 267-284.
    [5] J.P.E. Cleeton, C.D. Bohn, C.R. Mller, J.S. Dennis, S.A. Scott: Clean hydrogen production and electricity from coal via chemical looping: identifying a suitable operating regime, International Journal of Hydrogen Energy, 34 (2009), 1-12.
    [6] N. Gnanapragasam, B. Reddy, M. Rosen: Hydrogen production from coal using coal direct chemical looping and syngas chemical looping combustion systems: assessment of system operation and source requirements, International Journal of Hydrogen Energy, 34 (2009), 2606-2615.
    [7] E.E. Unmuth, L.H. Schwartz, J.B. Butt: Iron alloy Fischer-Tropsch catalysts I: Carburization studies of the Fe-Ni system, Journal of Catalysis, 63 (1980), 404-414.
    [8] A.J.H.M. Kock, H.M. Fortuin, J.W. Geus: The reduction behavior of supported iron catalysts in hydrogen or carbon monoxide atmospheres, Journal of Catalysis, 96 (1985), 261-275.
    [9] O.J. Wimmers, P. Arnoldy, J.A. Moulijn: Determination of the reduction mechanism by temperature-programmed reduction: application to small iron oxide (Fe2O3) particles, Journal of Chemical Physics, 90 (1986), 1331-1337.
    [10] G. Munteanu, L. Ilieva, D. Andreeva: Kinetic parameters obtained from TPR data for α-Fe2O3 and systems, Thermochimica Acta, 291 (1997), 171-177.
    [11] H.Y. Lin, Y.W. Chen, C. Li: The mechanism of reduction of iron oxide by hydrogen, Thermochimica Acta, 400 (2003), 61-67.
    [12] P. Pourghahramani, E. Forssberg: Reduction kinetics of mechanically activated hematite concentrate with hydrogen gas using nonisothermal methods, Thermochimica Acta, 454 (2007), 69-77.
    [13] J. Yu, J. Yue, Z. Liu, L. Dong, G. Xu, J. Zhu, Z. Duan, L. Sun: Kinetics and mechanism of solid reactions in a micro fluidized bed reactor, AIChE Journal, 56 (2010), 2905-2912.
    [14] J. Yu, X. Zeng, J. Zhang, M. Zhong, G. Zhang, Y. Wang, G. Xu: Isothermal differential characteristics of gas-solid reaction in micro-fluidized bed reactor, Fuel, 103 (2013), 29-36.
    [15] J. Yu, C. Yao, X. Zeng, S. Geng, L. Dong, Y. Wang, S. Gao, G. Xu: Biomass pyrolysis in a micro-fluidized bed reactor: Characterization and kinetics, Chemical Engineering Journal, 168 (2011), 839-847.
    [16] J. Yu, J. Zhu, F. Guo, Z. Duan, Y. Liu, G. Xu: Reaction kinetics and mechanism of biomass pylolysis in a micro-fluidized bed reactor, Journal of Fuel Chemistry and Technology, 38 (2010), 666-672.
    [17] F. Wang, X. Zeng, R. Shao, Y. Wang, J. Yu, G. Xu: Isothermal gasification of in situ/ex situ coal char with CO2 in a micro fluidized bed reaction analyzer, Energy & Fuels, 29 (2015), 4795-4802.
    [18] X. Zeng, F. Wang, Y. Wang, A. Li, J. Yu, G. Xu: Characterization of char gasification in a micro fluidized bed reaction analyzer, Energy & Fuels, 28 (2014), 1838-1845.
    [19] F. Wang, X. Zeng, Y. Wang, J. Yu, G. Xu: Characterization of coal char gasification with steam in a micro-fluidized bed reaction analyzer, Fuel Processing Technology, 141 (2016), 2-8.
    [20] Y. Zhang, M. Yao, G. Sun, S. Gao, G. Xu: Characteristics and kinetics of coked catalyst regeneration via steam gasification in a micro fluidized bed, I&EC Resarch, 53 (2014), 6316-6324.
    [21] Y. Zhang, M. Yao, S. Gao, G. Sun, G. Xu: Reactivity and kinetics for steam gasification of petroleum coke blended with black liquor in a micro fluidized bed, Applied Energy, 160 (2015), 820-828.
    [22] X. Wang, D. Yang, S. Ju, J. Peng, X. Duan: Thermodynamics and kinetics of carbothermal reduction of zinc ferrite by microwave heating, Transactions of Nonferrous Metals Society of China, 23 (2013), 3808-3815.
    [23] C. Schwandt, D.J. Fray: Use of molten salt fluxes and cathodic protection for preventing the oxidation of Titanium at elevated temperatures, Metallurgical and Materials Transactions B, 45 (2014), 2145-2152.
    [24] J. Ding: Investigation of thermodynamic equilibrium of MSWI fly ash during high-temperature treatment, Advanced Materials Research, 610-613 (2012), 1871-1875.
    [25] B. Janković, B. Adnađević, J. Jovanović: Application of model-fitting and model-free kinetics to the study of non-isothermal dehydration of equilibrium swollen poly (acrylic acid) hydrogel: Thermogravimetric analysis, Thermochimica Acta, 452 (2007), 106-115.
    [26] E.R. Monazam, R.W. Breault, R. Siriwardane: Kinetics of magnetite (Fe3O4) oxidation to hematite (Fe2O3) in air for chemical looping combustion, I&EC Resarch, 53 (2014), 13320-13328.
    [27] W.A. Johnson, R.F. Mehl: Reaction kinetics in processes of nucleation and growth, Trans. Aime, 135 (1939), 416-458.
    [28] M. Avrami: Kinetics of phase change I: General theory, The Journal of Chemical Physics, 7 (1939), 1103-1112.
    [29] M. Avrami: Kinetics of phase change II: Transformation-time relations for random distribution of nuclei, The Journal of Chemical Physics, 8 (1940), 212-224.
    [30] M. Avrami: Kinetics of phase change III: Granulation, phase change, and microstructure, The Journal of Chemical Physics, 9 (1941), 177-184.
    [31] J. Bessires, A. Bessires, J.J. Heizmann: Iron oxide reduction kinetics by hydrogen, International Journal of Hydrogen Energy, 5 (1979), 585-595.
    [32] M. Shimokawabe, R. Furuichi, T. Ishii: Influence of the preparation history of α-Fe2O3 on its reactivity for hydrogen reduction, Thermochimica Acta, 28 (1979), 287-305.
    [33] E.R. Monazam, R.W. Breault, R. Siriwardane, G. Richards, S. Carpenter: Kinetics of the reduction of hematite (Fe2O3) by methane (CH4) during chemical looping combustion: A global mechanism, Chemical Engineering Journal, 232 (2013), 478-487.
    [34] M.J. Tiernan, P.A. Barnes, G.M.B Parkes: Reduction of iron oxide catalysts: The investigation of kinetic parameters using rate perturbation and linear heating thermoanalytical techniques, Journal of Physical Chemistry B, 105 (2000), 220-228.
    [35] R. Chaigneau, R.H. Heerema: The influence of specific impurities on the nucleation and growth of magnetite during reduction of artificially prepared hematite, Metallurgical & Materials Transactions B, 22 (1991), 503-511.
    [36] P.R. Swann, N.J. Tighe: High voltage microscopy of the reduction of hematite to magnetite, Metallurgical Transactions B, 8 (1977), 479-487.
    [37] M. Ettabirou, B. Dupr, C. Gleitzer: Nucleation and early growth of magnetite on synthetic and natural hematite crystals, Reactivity of Solids, 1 (1986), 329-343.
    [38] P.C. Hayes, P. Grieveson: The effects of nucleation and growth on the reduction of Fe2O3 to Fe3O4, Metallurgical & Materials Transactions B, 12 (1981), 319-326.

    Full Text:

    Click here to access the Full Text

    Cite this article as:

    Chen H, Zheng Z, Chen Z, He X, He K. Multistep reduction kinetics of hematite (Fe2O3) to iron in a micro fluidized bed reactor by hydrogen at low temperatures. In: Kongoli F, Akiyama T, Nogami H, Saito K, Fujibayashi A, editors. Sustainable Industrial Processing Summit SIPS 2016 Volume 6: Yagi Intl. Symp. / Metals & Alloys Processing. Volume 6. Montreal(Canada): FLOGEN Star Outreach. 2016. p. 222-237.