Reaction Model for the Formation of Partially Reduced Iron by Heating Iron Ore-coal Char Composite Pellet in Oxygen Bearing Gas Flow

Iguchi, Yoshiaki

doi:10.2355/tetsutohagane1955.85.6_447

Cited by 5 publications

(1 citation statement)

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“…And they compared the rates of gasification reaction of the different carbonaceous materials (coal char, graphite, and coke). [6][7][8] Recently, Yang et al [9] reported that the carbothermic reduction of hematite-graphite composite pellets is dominated by the DR at the initial stage of reduction, and that it is determined by the indirect reduction together with the carbon solution loss reaction. Szendrei and Berge [10] provided the direct experimental evidence that the reduction of hematite with graphite progresses under a CO-CO 2 atmosphere in equilibrium with the various oxide phases by coupling a thermoanalyzer and quadruple mass spectrometry (QMS).…”

Section: Introductionmentioning

confidence: 99%

A Kinetic Study on Carbothermic Reduction of Hematite with Graphite Employing Thermogravimetry and Quadruple Mass Spectrometry

Jung¹,

2013

steel research int.

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The reduction of hematite-graphite pellet was investigated from a kinetic viewpoint in the temperature range of 1173-1473 K (900-12008C). The experimental procedure included thermogravimetric analysis (TGA) for measuring the weight change of the pellet and quadruple mass spectrometry (QMS) for monitoring the compositional change of the product gases. By applying a uniform internal reduction model to the current system, the activation energies for the reduction of Fe 3 O 4 to wustite and for that of wustite to Fe were evaluated to be 91.0 and 25.9 kJ mol À1 , respectively. Due to the product gas analyses by QMS, it was observed that the reduction rate of hematite-graphite pellet was accelerated up to the equilibrium concentration of CO determined by the carbon gasification curve.Changeover of reduction mechanism with increasing reduction degree was explained in terms of a schematic diagram based on the results obtained in the current study.

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Section: Introductionmentioning

confidence: 99%

A Kinetic Study on Carbothermic Reduction of Hematite with Graphite Employing Thermogravimetry and Quadruple Mass Spectrometry

Jung¹,

2013

steel research int.

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Topochemical approach of kinetics of the reduction of hematite to wüstite

Piotrowski

Mondal

Wiltowski

et al. 2007

Chemical Engineering Journal

139

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Mechanism of Carbothermic Reduction of Hematite in Hematite–Carbon Composite Pellets

2007

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Isothermal reduction experiments are carried out to study carbothermic reduction of hematite in hematite-graphite composite pellets. The carbothermic reduction is dominated by the direct reduction at the initial stage of reduction, and it is determined by the indirect reduction together with the carbon solution loss reaction when the CO partial pressure exceeds a certain value, which is dependent on the temperature. The reduction is greatly promoted due to the increment of the contact area between the hematite and graphite particles and enhancement of heat conduction in the hematite-graphite composite pellets.The indirect reduction together with the carbon solution loss reaction is markedly activated with increasing temperature. At a moderate carrier gas flow rate, the carbothermic reduction rate reaches the highest value. The reduction can also be effectively improved with decreasing the graphite particle size.The relationship of reduction products, heating temperature and holding time has been obtained from the XRD analysis results at the different stages for various temperatures under the present experimental conditions. The SEM observation indicates that the indirect reduction together with the carbon solution loss reaction should dominate the carbothermic reduction of hematite at the later stage of reduction.

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Reaction Model for the Formation of Partially Reduced Iron by Heating Iron Ore-coal Char Composite Pellet in Oxygen Bearing Gas Flow

Cited by 5 publications

References 6 publications

A Kinetic Study on Carbothermic Reduction of Hematite with Graphite Employing Thermogravimetry and Quadruple Mass Spectrometry

A Kinetic Study on Carbothermic Reduction of Hematite with Graphite Employing Thermogravimetry and Quadruple Mass Spectrometry

Topochemical approach of kinetics of the reduction of hematite to wüstite

Mechanism of Carbothermic Reduction of Hematite in Hematite–Carbon Composite Pellets

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