酸化鉄および鉄鉱石を還元した海綿鉄の再酸化挙動

概要

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Some characteristics of sponge-irons reduced from ferric oxide and iron-ores were studied. They were reduced by hydrogen in the temperature range 400 to 800℃ and re-oxidized by N_2-O_2 mixed gases at 400℃. The results were as follows. 1) In most cases, sponge-irons reduced in the range 600 to 700℃ showed maximum re-oxidation degrees. 2) The re-oxidation degree of those sponge-irons was increased with increasing the oxygen concentration of oxidizing atmosphere. 3) When the sponge-irons reduced at 600℃ were reheated at 700℃, re-oxidation showed lower values than that reduced at 700℃. 4) The behaviors of the re-oxidation were studied for several kinds of iron-ores. The sponge-irons reduced from limonite ores which have large surface areas, showed high re-oxidation degrees up to 90%. Those from hematite ores were also re-oxidized up to 40∿60%, those from magnetite ores, however, have small surface areas and lower re-oxidation degrees up to 10∿20%. Although pyrite cinders have generally small surface areas, those sponge-irons showed high re-oxidation degrees. 5) Re-oxidation degrees of sponge-irons could be considered to be controlled by such factors as specific surface area, lattice strain, pore distribution and temperature rise by the heat of re-oxidation. The factor of temperature is particularly important for low temperature re-oxidation.
社団法人日本鉄鋼協会の論文
1970-04-01