Method for electric steelmaking
AssigneeAmerican Combustion, Inc.
InventorGregory M. Gitman
Life of this patent
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Abstract
A method of melting and refining metals by high-temperature impinging combustion products generated by a single or multiple oxy-fuel or fuel/oxygen/air combustors that direct a flame towards a predetermined area of scrap to be melted. Once a portion of charged scrap contacted by the flame or flames is melted, an injection of solid carbonaceous fuel is initiated, preferably through a combustion tunnel of at least one of the combustors. High velocity oxygen is directed, simultaneously with carbonaceous material, through at least one dedicated nozzle toward injected solid carbonaceous fuel to mix with this fuel and to generate CO, which is capable of forming foamy slag. Optionally, a supersonic stream or multiple streams of additional oxygen is also directed toward the iron-carbon melt to initiate rapid melt refining.
Claims33
A method of steelmaking carried out in an electric arc furnace, comprising the steps of:
- a) heating the furnace using an electric arc;
- b) directing, through at least one burner/injector means, controllable flows of hydrocarbon fuel and a first oxidizing gas having an average oxygen content in excess of 30% to mix and to create a high velocity impinging flame directed toward a portion of scrap located at a desired area of the furnace in front of a flame discharge opening of the burner/injector means;
- c) maintaining the controllable flows of hydrocarbon fuel and the first oxidizing gas until a portion of scrap located at the desired area of the furnace is at least partially melted, thereby creating an iron-carbon melt and a slag layer covering the iron-carbon melt;
- d) then introducing, through the burner/injector means, a stream of solid particles of carbonaceous fuel carried by a compressed carrier gas toward the desired area of the furnace;
- and
- e) introducing, approximately simultaneously with the introduction of the solid carbonaceous fuel, a flow of a high velocity additional oxidizing gas having an average oxygen content in excess of 80% toward the iron-carbon melt at the desired area of the furnace previously occupied by scrap that has been at least partially melted, wherein the additional oxidizing gas at least partially reacts with the iron-carbon melt and the solid particles of carbonaceous fuel to create a stream of hot CO which is further at least partially oxidized to CO.sub.2 and exhausted with other flue gases from the furnace.
A method of making steel in an electric arc furnace having a slag discharge door and a steel tapping area, comprising the steps of:
- a) heating the furnace using an electric arc;
- b) introducing a plurality of flames each formed by burning a fluid hydrocarbon fuel and a first oxidizing gas and directing the flames each toward desired areas of the furnace occupied by charged scrap;
- c) maintaining the plurality of flames until the scrap located in the desired areas are at least partially melted, thereby creating an iron-carbon melt and a slag layer covering the iron-carbon melt;
- d) injecting a first flow of solid carbonaceous fuel carried by a compressed carrier gas into the furnace and simultaneously injecting a flow of the first oxidizing gas to mix with and at least partially oxidize the injected solid carbonaceous fuel, the injection being carded out into a region adjacent the slag discharge door of the furnace;
- and
- e) injecting a second flow of solid carbonaceous fuel carded by a compressed carrier gas into the furnace and simultaneously injecting a second flow of the first oxidizing gas to mix with and at least partially oxidize the injected solid carbonaceous fuel, the injection of the second flow of solid carbonaceous fuel and first oxidizing gas are directed into a region adjacent to the steel tapping opening of the furnace.
Dependencies are inferred from the claim text.