Kinetics of Cementite Formation from Reduced Iron in CO-H2-H2S Mixtures under Pressurized Conditions

Iguchi, Yoshiaki; Hori-I, Kazuyoshi; Shibata, Toshihiro

doi:10.2355/isijinternational.44.992

Cited by 11 publications

(5 citation statements)

References 19 publications

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“…[6][7][8][9][10][11][12][13][14][15][16][17][18][19][20][21] Despite of these many studies, the details of the reaction mechanism of Fe3C formation and its physical properties have not yet been established well. The reason for the lack in knowledge mainly comes from the metastability of the carbide causing experimental difficulties.…”

Section: Introductionmentioning

confidence: 99%

Cementite Formation from Magnetite under High Pressure Conditions

2013

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Measurements have been made of the rate of Fe3C formation from Fe3O4 powder and Fe3O4 single crystals at 773 K and 1 023 K under the high pressure of 0.5 and 1.0 MPa by using thermo-gravimetric method. Along with the kinetic study of Fe3C formation, high resolution TEM observation around the interface between Fe3O4 matrix and the formed Fe3C have been carried out to confirm the thermodynamically possible direct Fe3C formation from Fe3O4 without the formation of intermediate metallic Fe. Analysis of the rate results suggests that the reaction mechanism of Fe3C formation was possibly described by the sequential reactions of the conversion of Fe3O4 to Fe3C via intermediate metallic Fe although the metallic Fe existence was not confirmed by TEM observation. This inconsistency was explained by considering the relative reaction rates of Fe3C formation from Fe and Fe formation from Fe3O4. It was also found that not only the carbon activity of more than unity but also the low oxygen potential enough for metallic Fe existence might be required for the Fe3C formation.

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Section: Introductionmentioning

confidence: 99%

Cementite Formation from Magnetite under High Pressure Conditions

2013

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“…Many studies have been carried out for the Fe 3 C formation. [2][3][4][5][6][7][8][9][10][11][12][13][14][15][16][17] It is reported by Satoh et al 2,3) and Gudenau et al 18) that Fe 3 C may enhance carburization and smelting of reduced iron. However, Fe 3 C is a metastable phase and it may decompose into Fe and C in blast furnace.…”

Section: Introductionmentioning

confidence: 94%

Decomposition Behavior of Fe3C under Ar Atmosphere

Miki

Ishii

2014

ISIJ Int.

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Suppression of CO2 discharged from iron and steelmaking companies is an example of the biggest issues for the protection of global environment and sustainable growth of steelmaking industry. One of the efforts made to decrease the emission of CO2 in ironmaking process is blowing of hydrogen gas into blast furnace. Hydrogen gas can reduce iron oxide and form harmless H2O. Cementite (Fe3C) may be formed by introduction of hydrogen into blast furnace and play an important role on carburization and smelting behavior of reduced iron.In the present work, Fe3C sample was held at 800-1 100 K under Ar atmosphere to clarify the stability and the behavior of Fe3C phase. It was confirmed that metastable Fe3C phase will decompose under Ar atmosphere at 800 K and rapidly decompose at temperature over 900 K. Also, it was found that composite of nano-size C and Fe will form when Fe3C decompose.

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“…One way to control the amount of carbon deposited is to add steam to the gas, and therefore both carburization and steam reforming of methane can happen. 11) Much work has been done in the fundamentals of iron ore reduction [2][3][4][5][6][7][12][13][14][15][16] and carburization [17][18][19][20][21][22][23][24][25][26] in gas-based direct reduction processes. The catalytic behavior of sponge iron has been studied [27][28][29] regarding dry reforming of methane 27) or in conditions similar to blast furnace operations.…”

Section: Introductionmentioning

confidence: 99%

Kinetics Analysis of Steam Reforming of Methane on Sponge Iron

et al. 2022

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The kinetics of steam reforming of methane catalyzed by sponge iron was studied at temperatures between 875°C and 1 050°C. Results shows that sponge iron acts as a catalyst and methane conversion is increased in higher temperatures and with a higher H 2 /H 2 O ratio in the inlet gas. A kinetic model based on chemical reaction control fits well the experimental data up to methane conversion of 0.5 with an apparent activation energy of 258 kJ/mol. Pore diffusion limits the reaction rate more intensely at higher conversions of methane, higher temperatures, and larger particle size (from 9 to 17 mm). Two types of industrial pellets were compared showing that microstructural properties such as porosity, pore size, and grain size impact reduction rate with hydrogen and the catalytic property of the obtained sponge iron.

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Kinetics of Cementite Formation from Reduced Iron in CO-H2-H2S Mixtures under Pressurized Conditions

Cited by 11 publications

References 19 publications

Cementite Formation from Magnetite under High Pressure Conditions

Cementite Formation from Magnetite under High Pressure Conditions

Decomposition Behavior of Fe3C under Ar Atmosphere

Kinetics Analysis of Steam Reforming of Methane on Sponge Iron

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