In Situ Observation of Reduction Behavior of Hematite with Solid Carbon and Crystallographic Orientation between Hematite and Magnetite

Kashiwaya, Yoshiaki; Yamaguchi, Yasuhide; Kinoshita, Hiroshi; Ishii, Kuniyoshi

doi:10.2355/isijinternational.47.226

Cited by 20 publications

(16 citation statements)

References 13 publications

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“…The thickness of the carbon layer deposited was estimated to be 300 nm in other experiments. 5) This difference might be caused by the following: (1) a different sputtering rate between the carbon layer and hematite, (2) significant carbon diffusion into the hematite structure during sputtering. Because the distances along the horizontal axis are not absolute values for the different materials, a more precise experiment should be conducted in the future.…”

Section: Variation Of Peak Profiles Of C1s For Each Samplementioning

confidence: 99%

“…The details of the experimental method have been published elsewhere. 5) Figure 2(b) illustrates carbon ion implantation into hematite. Two kinds of implantation conditions were adopted so that the concentration of ions was 1.0×10 17 ions/cm 2 under one condition and 5.0×10 17 ions/cm 2 under the other.…”

Section: Preparation Of the Hematite Samplementioning

confidence: 99%

“…Figure 17 shows the mechanism between the carbon layer and hematite. 5) When the carbon layer becomes thicker than 300 nm, the evolved CO gas cannot be liberated to the Until a part of the carbon film is consumed by the reaction (4) and the gases are liberated to the outside, reactions (2) and (3) will proceed simultaneously, and thermodynamic coupling will occur. 10,11) On the other hand, the reaction between the implanted carbon and hematite is also initiated by reaction (2), and the mechanism for it is shown in Fig.…”

Section: )mentioning

confidence: 99%

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Binding Energy of Carbon Implanted into Hematite and in situ Observation of Reaction Behavior during Heating Up Experiment

et al. 2011

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It is widely known that the direct contact between solid carbon and iron oxide shows quite a fast reduction rate in comparison with CO gas reduction. However, it is difficult to sustain the physical contact between solid carbon and iron oxide. Furthermore, the contact mode will be different from the production method, which will affect the reaction kinetics strongly.In this study, different kinds of contacts between solid carbon and hematite were made to clarify the reaction mechanism. One contact mode is the deposition of the carbon layer on the hematite surface using a vacuum evaporation method. Another method is the implantation of carbon ions into hematite. Using XPS (X-ray photoelectron spectroscopy), the binding energy of Fe-O-C was measured. Heating under an argon atmosphere was carried out. Both samples showed quite different reaction behavior, though the temperature at the beginning of the reduction reaction was almost the same. From these results, it was determined that the position of carbon will change the reaction behavior drastically, because it is important how the CO gas escapes from the reaction site.

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Section: Variation Of Peak Profiles Of C1s For Each Samplementioning

confidence: 99%

Section: Preparation Of the Hematite Samplementioning

confidence: 99%

Section: )mentioning

confidence: 99%

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Binding Energy of Carbon Implanted into Hematite and in situ Observation of Reaction Behavior during Heating Up Experiment

et al. 2011

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“…Most of this material is reused either as a material in the manufacture of iron ore pellets for a melting furnace or as the coolant of a ladle converter. Recently, with respect to the development of a waste recycling method and the rise in the raw material price of steel products, the recycling process that collects pig iron by producing direct reduction iron (DRI) [1,2] using high purity iron mill scale has become a subject of much interest.…”

Section: Introductionmentioning

confidence: 99%

Optimization of process parameters for recycling of mill scale using Taguchi experimenal design

et al. 2010

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The present work submits an investigation about the optimum process parameters and quality improvement of mill scale recycling. With increasing concerns on environmental issues, the recycling of materials of all types has become an important issue. In this paper, an optimization method is developed to improve quality in mill scale recycling. The optimum configuration of process parameters to achieve high metallization efficiency was determined by experiments. The Taguchi method, the signal-to-noise (S/N) ratio, the analysis of variance (ANOVA) and rsponse surface optimization are employed to find the main effects and to determine their optimum process parameters. The significant process parameters were identified and their effects on mill scale recycling were studied. Finally, a confirmation experiment with the optimal levels of the process parameters was carried out to demonstrate the effectiveness of the Taguchi method.

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“…Carbon composite agglomerates (CCA) have been also used for coal-based new ironmaking processes such as FASTMET and ITmk3. Many investigations [2][3][4][5][6][7][8] have been carried out to understand the reduction, carburization and melting phenomena occurring in the CCA. In a microscopic view, particles of iron oxides, metallic Fe and carbonaceous material are mixed together and contacted with each other in the DRI and CCA.…”

Section: Introductionmentioning

confidence: 99%

Enhancement of Iron Melting Rate under the Co-existence of Graphite and Wüstite

2010

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Carburization and melting processes of solid Fe under the co-existence of graphite and wüstite has been investigated based on a confocal laser scanning microscope "in-situ" observation of the movement of the interface between Fe-C melt and solid Fe at 1 523 K. In the experiments, strong stirring flow at the surface of the Fe-C melt is observed. This flow is found to be Marangoni flow and is introduced by the surface tension gradient due to the difference of oxygen concentration between the Fe-C melt interface with graphite and solid iron. The velocity of Marangoni flow is measured from the moving velocities of bubbles at the molten Fe-C surface. The melting rate of Fe is analyzed by computational fluid flow simulations of the Fe-C melt. Based on these results, it is confirmed that the carburization and melting rate of solid Fe can be enhanced by allowing Fe-C melt to come into contact with wüstite and graphite simultaneously.

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In Situ Observation of Reduction Behavior of Hematite with Solid Carbon and Crystallographic Orientation between Hematite and Magnetite

Abstract: In addition, the growth direction of the lath magnetite formed on the hematite surface was

Cited by 20 publications

References 13 publications

Binding Energy of Carbon Implanted into Hematite and in situ Observation of Reaction Behavior during Heating Up Experiment

Binding Energy of Carbon Implanted into Hematite and in situ Observation of Reaction Behavior during Heating Up Experiment

Optimization of process parameters for recycling of mill scale using Taguchi experimenal design

Enhancement of Iron Melting Rate under the Co-existence of Graphite and Wüstite

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