Reduction of Iron Oxide Fines to Wustite with CO/CO2 Gas of Low Reducing Potential

Corbari, R.; Fruehan, Richard J.

doi:10.1007/s11663-009-9315-2

Cited by 25 publications

(17 citation statements)

References 19 publications

(39 reference statements)

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“…[8][9][10][11][12][13][14] Bohn and Cleeton [12] found the value of activation energy to be 90 ± 29 kJ/mol for the step of Fe 3 O 4 reduction to Fe 0.947 O in the overall reduction of hematite in carbon monoxide and carbon dioxide mixtures in a fluidized bed. They found that the reduction reaction was first order with respect to the concentration of CO which is consistent with our findings in this work.…”

Section: H Comparison With Related Previous Workmentioning

confidence: 99%

“…The reduction of hematite fines (highly porous oxide, moderately porous oxides, and dense oxides) to wustite with a CO and CO 2 mixture at the temperatures of 863 K to 1273 K (590°C to 1000°C) was studied by Corbari and Fruehan. [14] They found that in their experimental configuration external gas mass transfer controlled the first reduction step (Fe 2 O 3 to Fe 3 O 4 ), while the reduction mechanism of the second step (Fe 3 O 4 to Fe 0.947 O) varied with the temperature.…”

Section: Introductionmentioning

confidence: 99%

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Kinetics of the Reduction of Hematite Concentrate Particles by Carbon Monoxide Relevant to a Novel Flash Ironmaking Process

Chen

Mohassab

Zhang

et al. 2015

Metall and Materi Trans B

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A novel ironmaking process is under development at the University of Utah to produce iron directly from iron oxides concentrates by the gas-solid flash reaction using gaseous fuels and reductants. This process will reduce energy consumption and minimize carbon dioxide emissions. Having investigated the hydrogen reduction kinetics of magnetite and hematite concentrate particles relevant to the novel flash ironmaking process, the carbon monoxide reduction kinetics of hematite concentrate particles (average particle size 21 lm) was determined in the temperature range 1473 K to 1623 K (1200°C to 1350°C) under various carbon monoxide partial pressures. At 1623 K (1350°C) and residence time 5 seconds, the reduction degree of hematite concentrate particles was more than 90 pct under a pure carbon monoxide. This is slower than reduction by hydrogen but still significant, indicating that CO will contribute to the reduction of hematite concentrate in the flash process. The kinetics of CO reduction separately from hydrogen is important for understanding and analyzing the complex kinetics of hematite reduction by the H 2 + CO mixtures. The nucleation and growth rate equation with the Avrami parameter n = 1.0 adequately described the carbon monoxide reduction kinetics of hematite concentrate particles. The reduction rate is of 1st order with respect to the partial pressure of carbon monoxide and the activation energy of the reaction was 231 kJ/mol, indicating strong temperature dependence. The following complete rate equation was developed that can satisfactorily predict the carbon monoxide reduction kinetics of hematite concentrate particles and is suitable for the design of a flash reactor dX dt ¼ 1:91 Â 10 7 Â e À231000 RT Â pCO À pCO 2 K Â ð1 À XÞ; where X is the fraction of oxygen removed from iron oxide, R is 8.314 J/mol K, T is in K, p is in atm, and t is in seconds.

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Section: H Comparison With Related Previous Workmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

Kinetics of the Reduction of Hematite Concentrate Particles by Carbon Monoxide Relevant to a Novel Flash Ironmaking Process

Chen

Mohassab

Zhang

et al. 2015

Metall and Materi Trans B

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“…The first reduction step (Fe 2 O 3 to Fe 3 O 4 ) was fast and the second reduction step (Fe 3 O 4 to FeO) was the overall reaction-controlling step. [9,10] Moreover, it was found that the structure of the hematite fines tended to be loose and porous and to have a higher reduction degree and less metallic iron formation on the surface of the mineral fines with the elapse of time due to the carbon adherence to the hematite fines, and it helped to prevent the fines from binding together.…”

Section: Introductionmentioning

confidence: 99%

Density Functional Theory Study on the Carbon-Adhering Reaction on Fe3O4(111) Surface

Zhong

Wen

Zou

et al. 2015

Metall and Materi Trans B

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The density functional theory (DFT) has been employed to investigate the carbon-adhering reaction on Fe 3 O 4 (111) surface, which consists of two steps: (1) the adsorption of CO onto the Fe 3 O 4 (111) surface and (2) the second CO seizes an O atom from CO, which adsorbed on the surface, to form a CO 2 molecule and the C atom left behind adheres onto the Fe 3 O 4 (111) surface. At step 1, there are five stable configurations of CO adsorbed onto Fe oct2 -terminated Fe 3 O 4 (111) surface and four stable formations of CO adsorbed onto the Fe tet1 -terminated Fe 3 O 4 (111) surface. The top configurations of these two surfaces are most stable. Moreover, a density of the state (DOS) analysis is used to investigate the bonding mechanism of CO adsorbed onto these two surfaces. The results reveal the new C-O bonds generation on two surfaces, which is important and necessary for the formation of a CO 2 molecule. Besides, the transition states (TS) are searched to analyze the energy barrier in the process of CO 2 desorption from two surfaces. The result indicates that the oxidation reaction of adsorbed CO molecule and surface O atom is feasible. For step 2, the result shows that the carbon-adhering reaction occurs only on the top site of Fe oct2 atom and the magnetite plays a catalytic role in the carbonadhering reaction process.

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“…25 It was concluded that the first step (Fe 2 O 3 RFe 3 O 4 ) is fast and can be separated from the second step (Fe 3 O 4 RFeO) by TG curves between 590 and 1000uC. Thus, the step by step method was used to determine the exact thermodynamic data.…”

Section: Resultsmentioning

confidence: 99%

Influences of non-stoichiometry on thermodynamics and kinetics of iron oxides reduction processes

Zhang¹,

Zhang

Zou

et al. 2013

Ironmaking & Steelmaking

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Non-stoichiometry influences both the thermodynamic and kinetic analyses of the iron oxide redox processes. The thermochemical data of iron oxide redox reactions in various textbooks are not consistent, and the kinetic characteristics are not well understood because of the nonstoichiometry. To clarify such confusions, some famous thermodynamic data are compared, and highly precise experimental work conducted for verification. It is shown that the thermodynamic data for the pure iron oxide reduction reactions from JANAF agree well with the experimental results; the eutectoid temperature of iron oxides was proven to be 576uC; Dieckmann's defect model of magnetite was proven in good agreement with the experimental results only at high oxygen activities but not low oxygen activities; and the dependences of iron deficiency on Dwt-% (weight loss ratio) and Fe 2z % (ferrous ratio) were calculated and experimentally verified in pure iron oxides reduction processes.

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Reduction of Iron Oxide Fines to Wustite with CO/CO2 Gas of Low Reducing Potential

Cited by 25 publications

References 19 publications

Kinetics of the Reduction of Hematite Concentrate Particles by Carbon Monoxide Relevant to a Novel Flash Ironmaking Process

Kinetics of the Reduction of Hematite Concentrate Particles by Carbon Monoxide Relevant to a Novel Flash Ironmaking Process

Density Functional Theory Study on the Carbon-Adhering Reaction on Fe3O4(111) Surface

Influences of non-stoichiometry on thermodynamics and kinetics of iron oxides reduction processes

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