[Table of Contents]

Plasma and Fusion Research

Volume 3, S1085 (2008)

Regular Articles

Investigation of the Microwave Iron-Production Process with Multipoint Pyrometric and Spectroscopic Measurements
Akihiro MATSUBARA, Sadatsugu TAKAYAMA1), Kazuya NAKAYAMA, Takahiro KANEBA, Masahiro TOMIMOTO, Ryuichi AKIYAMA1), Shigeki OKAJIMA and Motoyasu SATO1)
Chubu University, 1200 Matsumoto, Kasugai, Aichi 487-8501, Japan
1)
National Institute for Fusion Science, 322-6 Oroshi, Toki, Gifu 509-5292, Japan
(Received 19 November 2007 / Accepted 11 February 2008 / Published 5 August 2008)

Abstract

Carbothermic reduction of magnetite in a 2.45-GHz microwave multimode furnace was investigated with multipoint pyrometric and spectroscopic measurements. Both experimental results emphasize the importance of surface heating of the specimen by microwave-generated plasma for reducing iron oxide. The pyrometric observation shows a shift of the heating mode from the direct volumetric heating by microwave to the surface heating by microwave-generated plasma, when the temperature of the material suddenly rises from ∼800 to ∼1000 °C accompanied by light emission from plasma. The emission spectrum in the near-UV range (240-310 nm) changes drastically from a continuous spectrum to a line emission spectrum of iron, representing progress of carbothermic reduction of iron oxide. The multipoint spectroscopic observation indicates extensive carbothermic reduction occurring on the entire upper surface of the specimen.

Keywords

microwave iron production, carbothermic reduction, direct volumetric heating by microwave, surface heating by microwave-generated plasma, pyrometric measurement, spectroscopic measurement, near-UV emission, continuous spectrum, cathodoluminescence, plasma surface interaction.

DOI: 10.1585/pfr.3.S1085

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This paper may be cited as follows:

Akihiro MATSUBARA, Sadatsugu TAKAYAMA, Kazuya NAKAYAMA, Takahiro KANEBA, Masahiro TOMIMOTO, Ryuichi AKIYAMA, Shigeki OKAJIMA and Motoyasu SATO, Plasma Fusion Res. 3, S1085 (2008).