日本金属学会誌

J. Japan Inst. Metals, Vol. 32, No. 10 (1968),
pp. 939-943

Study on the Structure of Itabira Iron Ore Reduced by H2-H2O Gas Mixture

Genjiro Mima1, Shinichi Morita2, Junzo Takahashi1 and Masaharu Yamaguchi1

1Department of Metallurgy, Facullty of Engineering, Osaka University, Osaka
2Graduate Student of Matallurgical Engineering, Osaka University; now, Mint Bureau, Osaka

Abstract:

The mechanism in the gaseous reduction of iron ore is very confusing and presents many problems still unsolved.
This is because several processes are occurring simultaneously and moreover, there are a large number of variables. In order to provide additional information to the reduction mechanism, in this investigation, the structural change of the ore, especially, the formation process of the sponge iron has been studied by means of optical microscopy and electron microscopy. Itabira iron ore was inserted in a horizontal tube furnace and reduced at 900°C by a H2-H2O gas mixture. Thin foils of iron ore and reduced iron were prepared and examined by transmission electron microscopy. It has been frequently observed that some of iron ore crystals are damaged on exposing to the electron beam. Selected area diffraction patterns obtained from these damaged iron ore crystals have shown that iron ore crystals transform to an amorphous state.
Optical and electron microscopic observations have revealed that the small reduced iron particles, as reduction proceeds, coalesce and grow, and finally coarse iron particles are formed.


(Received 1968/2/27)

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