Difference in carbo-thermal reduction reaction kinetics of NiO in microwave E- and H-fields

Noboru Yoshikawa; Etsuko Ishizuka; Ken ichi Mashiko; Shoji Taniguchi

doi:10.1016/j.matlet.2006.08.030

Difference in carbo-thermal reduction reaction kinetics of NiO in microwave E- and H-fields

Noboru Yoshikawa, Etsuko Ishizuka, Ken ichi Mashiko, Shoji Taniguchi

ENG - Metallurgy

Research output: Contribution to journal › Article › peer-review

18 Citations (Scopus)

Abstract

A powder mixture of NiO and graphite was heated in a single mode-microwave (MW) applicator at 2.45 GHz for carbo-thermal reduction of NiO. The specimen was placed in the wave guide at maximum positions of either electric (E) field or magnetic (H) field and kept at a constant temperature. A tendency was observed that the reduction rate at 600 °C was larger in the H-field than in the E-field. Considering the fact that NiO can be heated only in the E-field, while graphite can be heated in both fields, graphite particles in the powder mixture might be selectively heated in the H-field. Hence, it is postulated that a microscopic temperature gradient is formed more in the H-field, which caused the gas convection, then the mass transfer and the gas-solid reaction is enhanced, so the enhanced reduction kinetics resulted, eventually.

Original language	English
Pages (from-to)	2096-2099
Number of pages	4
Journal	Materials Letters
Volume	61
Issue number	10
DOIs	https://doi.org/10.1016/j.matlet.2006.08.030
Publication status	Published - 2007 Apr 1

Keywords

Carbo-thermal reduction
Electric field
Kinetics
Magnetic field
Microwave
Nickel oxide

ASJC Scopus subject areas

Materials Science(all)
Condensed Matter Physics
Mechanics of Materials
Mechanical Engineering

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title = "Difference in carbo-thermal reduction reaction kinetics of NiO in microwave E- and H-fields",

abstract = "A powder mixture of NiO and graphite was heated in a single mode-microwave (MW) applicator at 2.45 GHz for carbo-thermal reduction of NiO. The specimen was placed in the wave guide at maximum positions of either electric (E) field or magnetic (H) field and kept at a constant temperature. A tendency was observed that the reduction rate at 600 °C was larger in the H-field than in the E-field. Considering the fact that NiO can be heated only in the E-field, while graphite can be heated in both fields, graphite particles in the powder mixture might be selectively heated in the H-field. Hence, it is postulated that a microscopic temperature gradient is formed more in the H-field, which caused the gas convection, then the mass transfer and the gas-solid reaction is enhanced, so the enhanced reduction kinetics resulted, eventually.",

keywords = "Carbo-thermal reduction, Electric field, Kinetics, Magnetic field, Microwave, Nickel oxide",

author = "Noboru Yoshikawa and Etsuko Ishizuka and Mashiko, {Ken ichi} and Shoji Taniguchi",

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T1 - Difference in carbo-thermal reduction reaction kinetics of NiO in microwave E- and H-fields

AU - Yoshikawa, Noboru

AU - Ishizuka, Etsuko

AU - Mashiko, Ken ichi

AU - Taniguchi, Shoji

PY - 2007/4/1

Y1 - 2007/4/1

N2 - A powder mixture of NiO and graphite was heated in a single mode-microwave (MW) applicator at 2.45 GHz for carbo-thermal reduction of NiO. The specimen was placed in the wave guide at maximum positions of either electric (E) field or magnetic (H) field and kept at a constant temperature. A tendency was observed that the reduction rate at 600 °C was larger in the H-field than in the E-field. Considering the fact that NiO can be heated only in the E-field, while graphite can be heated in both fields, graphite particles in the powder mixture might be selectively heated in the H-field. Hence, it is postulated that a microscopic temperature gradient is formed more in the H-field, which caused the gas convection, then the mass transfer and the gas-solid reaction is enhanced, so the enhanced reduction kinetics resulted, eventually.

AB - A powder mixture of NiO and graphite was heated in a single mode-microwave (MW) applicator at 2.45 GHz for carbo-thermal reduction of NiO. The specimen was placed in the wave guide at maximum positions of either electric (E) field or magnetic (H) field and kept at a constant temperature. A tendency was observed that the reduction rate at 600 °C was larger in the H-field than in the E-field. Considering the fact that NiO can be heated only in the E-field, while graphite can be heated in both fields, graphite particles in the powder mixture might be selectively heated in the H-field. Hence, it is postulated that a microscopic temperature gradient is formed more in the H-field, which caused the gas convection, then the mass transfer and the gas-solid reaction is enhanced, so the enhanced reduction kinetics resulted, eventually.

KW - Carbo-thermal reduction

KW - Electric field

KW - Kinetics

KW - Magnetic field

KW - Microwave

KW - Nickel oxide

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SP - 2096

EP - 2099

JO - Materials Letters

JF - Materials Letters

SN - 0167-577X

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ER -

Difference in carbo-thermal reduction reaction kinetics of NiO in microwave E- and H-fields

Abstract

Keywords

ASJC Scopus subject areas

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