METHOD FOR MAKING STEEL IN ELECTRIC-ARC FURNACE Russian patent published in 1997 - IPC

FIELD: ferrous metallurgy. SUBSTANCE: increased amount of liquid cast iron in charge with simultaneous reducing amount of hard cast iron in it at lower energy consumed are achieved due to following. Method implies charging of hard oxidizing agents, slag-forming materials, solid metallic burden from iron-steel scrap, their heating, pouring of liquid cast iron, blasting of bath with gaseous oxidizing agent, melting, oxidizing and reducing refining of melt and its tapping. Hard oxidizing agents and hard cast iron are introduced in the form of pigs of hard oxidizing agent poured over with liquid cast iron. Used as metallic burden is hard and liquid cast iron. Total amount of cast iron is maintained within 51-95% of total mass of metallic burden with keeping relation of hard cast iron to liquid cast iron equal to 1: (0.1-10). Pigs contain oxidic material poured over with cast iron in relation of 1:(1.5-9). Total amount of oxygen in oxidic material is equal to or higher than amount needed for complete oxidizing of cast iron components possessing higher attraction towards oxygen as compared with carbon. Additionally to hard oxidizer connected with hard iron, introduced to burden is hard oxidizer in free state in amount of 5-50 kg per 1 t of cast iron. Relation of iron-steel scrap to liquid cast iron in burden is maintained within limits of 1:(0.5-10). Used as hard oxidizer in free state - iron ore, agglomerate, iron ore concentrate, scale. Pigs and iron-steel scrap prior to charging into bath are preliminarily heated to temperature of 200-850 C. Used as slag-creating materials - lime, sandstone, dolomite. EFFECT: high efficiency. 6 cl, 1 tbl