PROCESS OF STEEL MELTING IN OPEN-HEARTH FURNACE Russian patent published in 1998 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: invention is related to ferrous metallurgy where such waste of production as slogs of converter operation, separated slogs, scale and so on are used as iron-carrying starting materials. In agreement with invention process is realized thanks to usage of 15% of metal scrap and 25% of liquid pig iron from charge of furnace. Full charge is obtained by injection of mixture containing iron- carrying starting material, coal and fluorite in proportion 1.0:0.4:0.15. This mixture in the amount of 2.0 t of scrap is loaded on to heated scrap, is heated additionally together with scrap to pouring of pig iron with coefficient of air excess not less than 1. After pouring of pig iron and melting of scrap the rest of mixture in the amount of 30.0-70.0 t/h is added simultaneously with oxygen blow-through of bath. Intensity of blow-through during this time is periodically changed from maximum one in the course of 15-25 s to minimum one in the course of 5-10 s. Feed of mixture is stopped after filling of bath due to reduction of iron and process is brought to final melting. EFFECT: improved quality of steel thanks to decreased fouling with non-ferrous impurities, improved ecological situation and reduced production cost. 1 cl