Abstract: A plant for the continuous manufacture of steel includes a direct reduction furnace for producing direct reduced iron (DRI) and a stationary electric arc furnace for melting the DRI. The electric arc furnace has a plurality of electrodes for melting the DRI. Heat for melting the charge material is preferably provided by open arcs between the electrodes and the metal bath. The slag preferably has low basicity to reduce the rate of refractory erosion, and preferably contains about 8 to 20% by weight MgO, about 7 to 30% by weight FeO and has a basicity of about 1.5 to 2.0. Preferably, the direct reduction furnace is a shaft furnace and is located above the electric arc furnace so that the direct reduced iron can be fed to the electric arc furnace by gravity through inclined conduits.

Abstract: A plant for the continuous manufacture of steel comprises a direct reduction furnace for producing direct reduced iron (DRI) and a stationary electric arc furnace for melting the DRI. The electric arc furnace has a plurality of electrodes for melting the DRI. Inside the electric arc furnace, a bath of molten steel and a continuous slag layer are maintained, the steel bath preferably having a volume of approximately 7 to 13 tap volumes. Heat for melting the charge material is preferably provided by open arcs between the electrodes and the metal bath. The slag preferably has low basicity to reduce the rate of refractory erosion, and preferably contains about 8 to 20% by weight MgO, about 7 to 30% by weight FeO and has a basicity of about 1.5 to 2.0. Preferably, the direct reduction furnace is a shaft furnace which is closely coupled to the electric arc furnace.

Abstract: A process for the manufacture of steel in which a charge material comprising direct reduced iron, and optionally containing steel scrap, is continuously charged into a stationary electric arc furnace. Inside the furnace, a bath of molten steel and a continuous slag layer are maintained, the steel bath preferably having a volume of approximately 7 to 13 tap volumes. Heat for melting the charge material is preferably provided by open arcs between the electrodes and the metal bath, with the slag layer preferably being superheated to about 40 to 150° C. above the bath temperature. In order to prevent excessive superheating, the slag preferably has a melting point substantially the same as, or greater than, the bath temperature, with the slag melting temperature being adjustable by varying the amount of MgO in the slag. The slag preferably has low basicity to reduce the rate of refractory erosion.

Abstract: A process for the manufacture of steel in which a charge material comprising direct reduced iron, and optionally containing steel scrap, is continuously charged into a stationary electric arc furnace. Inside the furnace, a bath of molten steel and a continuous slag layer are maintained, the steel bath preferably having a volume of approximately 7 to 13 tap volumes. Heat for melting the charge material is preferably provided by open arcs between the electrodes and the metal bath, with the slag layer preferably being superheated to about 40 to 150° C. above the bath temperature. In order to prevent excessive superheating, the slag preferably has a melting point substantially the same as, or greater than, the bath temperature, with the slag melting temperature being adjustable by varying the amount of MgO in the slag. The slag preferably has low basicity to reduce the rate of refractory erosion.

Abstract: A method for effecting direct reduction of iron oxides in the form of lumps or pellets, in which an ore burden is passed downwardly successively through prereduction and metallization zones of a shaft furnace while passing a flow of rich fuel gas produced by external partial combustion upwardly in counter current through the prereduction zone, and passing a flow of reducing gas in cocurrent though the metallization zone. The flow of reducing gas is an independent flow that has not been subject to external combustion, and an intermediate zone is provided forming a narrowed throat between the prereduction and metallization zones. The reducing gas is introduced at a boundary between the intermediate and metallization zones, such that passage of rich fuel gas from the prereduction zone to the metallization zone is inhibited. The gas flows should be controlled so that about 5% to 10% of the volume of reducing gas passes upwardly from the intermediate zone to the prereduction zone.