Effect of Microwave Irradiation on Hydrothermal Treatment of Blast Furnace Slag

Tae, Soon-Jae; Tanaka, Toshihiro; Morita, Kazuki

doi:10.2355/isijinternational.49.1259

Cited by 13 publications

(10 citation statements)

References 11 publications

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“…It was reported as an incredible and surprising phenomenon that powdered metal could be heated by microwave [ 6 ], because it was generally considered that metal reflects the electromagnetic field and is not possible to be heated. This phenomenon introduced the possibility of microwave application to the metal industry and promoted further research for metallurgists [ 7 , 8 ].…”

Section: Introductionmentioning

confidence: 99%

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

Fujisaki

Ikeda

2013

Materials

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To connect different scale models in the multi-scale problem of microwave use, equivalent material constants were researched numerically by a three-dimensional electromagnetic field, taking into account eddy current and displacement current. A volume averaged method and a standing wave method were used to introduce the equivalent material constants; water particles and aluminum particles are used as composite materials. Consumed electrical power is used for the evaluation. Water particles have the same equivalent material constants for both methods; the same electrical power is obtained for both the precise model (micro-model) and the homogeneous model (macro-model). However, aluminum particles have dissimilar equivalent material constants for both methods; different electric power is obtained for both models. The varying electromagnetic phenomena are derived from the expression of eddy current. For small electrical conductivity such as water, the macro-current which flows in the macro-model and the micro-current which flows in the micro-model express the same electromagnetic phenomena. However, for large electrical conductivity such as aluminum, the macro-current and micro-current express different electromagnetic phenomena. The eddy current which is observed in the micro-model is not expressed by the macro-model. Therefore, the equivalent material constant derived from the volume averaged method and the standing wave method is applicable to water with a small electrical conductivity, although not applicable to aluminum with a large electrical conductivity.

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Section: Introductionmentioning

confidence: 99%

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

Fujisaki

Ikeda

2013

Materials

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“…Trial and semi-practical application of microwave tech-© 2011 ISIJ nique has been begun for environmental techniques 7,8) and metal industries [9][10][11][12][13][14] due to the possibility to reduce CO2 emission because this process does not need fossil resources represented by oil. Microwave can be widely applied, for example, for carbo-thermal reduction to directly produce pig iron, sintering of iron ores, process of metal recycling from slags and wasted materials generated internally in steel plants, drying refractory lining and so forth in place of original equipment.…”

Section: Introductionmentioning

confidence: 99%

Dehydration Behavior of Goethite Blended with Graphite by Microwave Heating

et al. 2011

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In ironmaking and steelmaking processes, dehydration of wet substances and minerals combined by H2O are often recognized to be a key to stable practices. This study aims at understanding dehydration behavior of goethite blended with graphite by microwave treatment simulating drying wet sludge and poor iron ore with combined water.Firstly blend specimens with various conditions, powdery or pelletized, were heated by microwave apparatus. Dehydration rate of goethite increased with increasing temperature. Denser specimen of pelletized was confirmed to be less effective to heat up the whole part. It was found that surplus addition of graphite decreased efficiency in dehydration rate. Thus, it was estimated that a specimen with smaller amount of graphite, whose blend ratio of FeO(OH):C was 1:1, had sufficiently larger distance between graphite particles, through which microwaves could adequately penetrate into the core of the specimen. To prove this hypothesis, Network Analyzer helped evaluate penetration depth of microwave by the measurement of permittivity. The measured results showed that penetration depth decreased with increasing apparent density consistently with the heating behavior by microwave treatment. At the blend ratio of 1:2 of FeO(OH):C, however, the specimen was estimated to behave as if it was under percolation.

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“…6) Crystallization of blast furnace slag is also researched. 7) However, though a lot of experimental data are shown to clarify the reduction reaction and to obtain the useful suggestions, 8,9) some of them are not explained theoretically enough. Numerical calculation in combination with the experimental method is expected to be an important one to solve it and to obtain the improved process.…”

Section: Introductionmentioning

confidence: 99%

Shape Anisotropy of Electromagnetic Materials in Application of Microwave by Micro-sized Numerical Electromagnetic Field Calculation

Fujisaki

2012

ISIJ Int.

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As the fundamental characteristics of microwave application, which is expected to be one of the useful technologies in the reduction reaction of iron oxide, electromagnetic anisotropic characteristics of electromagnetic materials in application of microwave are observed by micro-sized numerical high frequency electromagnetic computation. In assuming that the micro-sized unit structure is repeated in 3-dimensional directions and its size is much smaller than the electromagnetic wave length, the micro-sized electromagnetic field calculation using finite element method and jω method is carried out. In considering the bar shape and the cube shape as a micro-structure of electromagnetic material, the bar shape micro-structure has anisotropic characteristics, though cube shape micro-structure has isotropic ones. The generation of depolarization field within the micro-structure causes the difference of electromagnetic characteristics and the anisotropy.

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Effect of Microwave Irradiation on Hydrothermal Treatment of Blast Furnace Slag

Cited by 13 publications

References 11 publications

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

Equivalent Electromagnetic Constants for Microwave Application to Composite Materials for the Multi-Scale Problem

Dehydration Behavior of Goethite Blended with Graphite by Microwave Heating

Shape Anisotropy of Electromagnetic Materials in Application of Microwave by Micro-sized Numerical Electromagnetic Field Calculation

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