自溶性焼結鉱の製造ならびに100%配合による高炉操業

Abstract

In the sinter which is self-fluxed by adding the finely ground limestone, the formation of unreducible fayalite is obstructed or the fayalite disappears. Moreover, the glassy silicate matrix which prevents a gas reduction by surrounding iron oxide will disappear.For making self-fluxing sinter, the exact control of blending and weighing, especially the correct addition of return fines, coke breeze and limestone is the most important. The suitable size of coke breeze as sinter fuel is under 5mm and one of limestone is under 3mm.As a blast furnace burden, the self-fluxing sinter proves most effective when a furnace is operated with its 100% sinter burden. It seems possible to assume that by this 100% self-fluxing sinter burden practice, the coke rate can be reduced to below 550kg per metric ton of pig iron and the productivity of a furnace can be increased to above 1.3 metric tons per day per cubic meter of inner volume.The results obtained by this practice at Kokura Steel Works, Sumitomo Metal Industries Ltd. were satisfactory and proved the above mentioned improvements in its operating data.We think, this practice, using a fully self-fluxed sinter burden, is the last step in the series of ore beneficiation process that are found to be advantageous by roasting ores before charging.