Studies on the reduction of hematite by carbon

Srinivasan, Narayanaswamy; Lahiri, A.

doi:10.1007/bf02656367

Cited by 117 publications

(101 citation statements)

References 4 publications

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“…(1)- (3). For the metallic oxide-carbon (or carbides) reduction system, it is generally believed that indirect reactions prevail during the whole course of the reduction 9,[22][23][24][25][26][27] and a coupling phenomenon of carbon gasification and metal oxide reduction takes place.…”

Section: Theoreticalmentioning

confidence: 99%

Carbothermic Reduction of Synthetic Chromite with/without the Addition of Iron Powder

Teng

Wang

et al. 2016

ISIJ Int.

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Carbothermic reduction of chromite is an important industrial process for extracting chromium from the chromite. To have a better understanding of the effect of iron on the carbothermic reduction of chromite, the reduction of synthetic chromite (FeCr 2 O 4 ) by graphite with/without the addition of iron powder was investigated in this paper by Thermogravimetric Analysis (TGA) in argon atmosphere. The fractional reduced samples were examined by SEM/EDS and XRD analysis, and the reduction process was thermodynamically and kinetically evaluated. The experimental results show that the iron powder addition enhances the reduction of FeCr 2 O 4 and this effect increases when increased amounts of iron powder are added. This phenomenon is attributed to the in situ dissolution of chromium into the iron and mixed carbide (Cr,Fe) 7 C 3 , which can decrease the activity of the nascent chromium formed by the reduction of the FeCr 2 O 4 . The experimental results indicate that the reduction of FeCr 2 O 4 with up to 80 wt.% iron powder addition is likely to be a single-step process and the kinetic analysis suggests that the reduction reaction is likely to be either (a) chemical reaction at the surface of FeCr 2 O 4 or (b) diffusional dissolution of the product (FeCr 2 ) into the iron/alloy particles or the mixed control of (a) and (b).

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Section: Theoreticalmentioning

confidence: 99%

Carbothermic Reduction of Synthetic Chromite with/without the Addition of Iron Powder

Teng

Wang

et al. 2016

ISIJ Int.

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“…19) [22][23][24][25] Furthermore, while the direct reduction of carbon with Fe 2 O 3 initiates the removal of oxygen in the composite pellets, it is well-known that the gaseous intermediate indirect reduction with CO and CO 2 is the dominant reaction occurring within the composite pellets. And as pointed out by Rao,22) Srinivisan and Lahiri, 23) Abraham and Ghosh, 24) and Fruehan,25) the carbon gasification (Boudouard reaction) plays an important role in determining the overall rate, as expressed in reaction (3). This results in the production of CO gases within the pellet to further stimulate reduction by reaction (4) …”

Section: Reduction Tests Using a Modified Microbalancementioning

confidence: 99%

DRI from Recycled Iron Bearing Wastes for Lower Carbon in the Blast Furnace

2015

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Reduction of Fe-bearing FINEX process waste and carbon composite pellets from 1 373 K to 1 573 K to produce DRI (direct reduced iron) for use in the blast furnace was investigated using a modified thermogravimetric analyzer. Reduction from the initial Fe 2 O 3 was not uniform throughout the composite pellet. Oxygen removal from the Fe 2 O 3 rich composite pellets over 84% was only observed at 1 573 K. Lower temperatures resulted in significantly un-reduced FeO t due to the premature consumption of the carbon. A peripheral boundary of FeO t ·Al 2 O 3 and 2FeO·SiO 2 phases surrounding the reducible FeO t was observed in some of the partially reduced cross-sectional SEM (scanning electron microscope) images that could hinder reduction. From the apparent activation energy, interfacial reaction seems to affect the kinetics of the Fe-bearing process waste composite pellets. Bursting of pre-dried composite pellets containing less than 2 mass% moisture was simulated in a RHF hearth simulator. From direct observation of pellets charged between 1 173 K to 1 573 K, medium-sized pellets between 9.4 to 12.4 mm diameter showed less bursting of the pellet, when charged below 1 273 K. In addition, modification of the physical strength of the hard bedrock formed from pellet bursting could be softened with additions of SiO 2 .

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“…Rao 4) found that the availability of CO governs the reduction process in the mixture of hematite and graphite and that the carbon gasification reaction determines the rate controlling step for the overall process. Srinivasan and Lahiri 5) showed that the activation energy of the carbothermic reduction of hematite by graphite has been found to decrease with progress in reduction, indicating a possible changeover in reaction mechanism. Fruehan 6) confirmed that the reduction of Fe2O3 to FeO takes place by means of the gaseous intermediates CO and CO2, and that the overall rate is controlled by the carbon oxidation by CO2.…”

Section: Introductionmentioning

confidence: 99%

Evaluation of Reduction Progress of Raw Titanomagnetite and Char Composite by Thermogravimetry

Jung

2013

ISIJ Int.

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Studies on the reduction of hematite by carbon

Cited by 117 publications

References 4 publications

Carbothermic Reduction of Synthetic Chromite with/without the Addition of Iron Powder

Carbothermic Reduction of Synthetic Chromite with/without the Addition of Iron Powder

DRI from Recycled Iron Bearing Wastes for Lower Carbon in the Blast Furnace

Evaluation of Reduction Progress of Raw Titanomagnetite and Char Composite by Thermogravimetry

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