Abstract
Conception and evaluation test methods on the qualities of raw materials for gaseous direct reduction as well as the qualities of direct reduced iron are described. Emphasis is on the clarification of the difference of desirable qualities of the direct reduction feeds from those of traditional blast furnace feeds.
The raw materials for the gaseous direct reduction should have,
1) high iron content with small amount of such impurities as phosphorous, sulphur and alkali,
2) high reducibility to make retention time of the burden in the furnace shorter,
3) less fines generation characteristic to decrease the furnace pressure drop lower,
4) less clustering tendency to guarantee smooth decending of the burden in the furnace.
To evaluate those properties, the static bed reduction test, Linder rotating reduction test and the clustering test were adopted. Small stainless steel basket which had been charged from top of an actual operating shaft furnace were taken out from the discharge point and the properties of reduced materials were investigated. Test results of actual shaft furnace showed good coincidence with those of laboratory scale.
