上底吹き転炉を用いた鉄鉱石の溶融還元における二次燃焼・着熱挙動と石炭原単位の関係(マンガン, クロム, 鉄の溶融還元とスクラップ溶解)(<特集>転炉機能の拡大)

概要

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Factors affecting the coal consumption in the smelting reduction of iron ore with top-and-bottom blowing converter were investigated. (1) According to the results of 5 t and 100 t scale experiments, coal consumption increased with the Volatile Matter (VM) content in coal and with the degree of contact of O_2 and metal. The decrease of heat loss unexpectedly resulted in the drop, not of coal consumption, but of post combustion ratio. (2) Coal consumption did not drop monotonously with post combustion ratio, but increased again in the region of high post combustion. (3) Experimental results were explained by introducing the concept of "the necessary amount of fixed carbon". (4) One route for decreasing the consumption of high VM coal is to decrease the amount of fixed carbon burned directly or indirectly by O_2. The degree of combustion of fixed carbon by O_2 was defined as J value (kg-fixed carbon burned/Nm^3-O_2). The minimum J value obtained in experiments was 0.25 kg-C/Nm^3-O_2. It was ascertained by fundamental experiment that transport of oxygen in slag through iron ions limits the minimum J value. Therefore, in order to decrease the consumption of high VM coal, it is necessary to combine pretreatment of coal and ore with smelting reduction process.
社団法人日本鉄鋼協会の論文
1990-11-01