A method for producing a molten steel may provide: solid-state direct reduced iron containing 3.0% by mass or more of SiO.sub.2 and Al.sub.2O.sub.3 in total and 1.0% by mass or more of carbon, a ratio of a metallic iron to a total iron content contained in the solid-state direct reduced iron being 90% by mass or more, and an excess carbon content Cx to the carbon contained in the solid-state direct reduced iron being 0.2% by mass or more. Such methods may include: a slag separation including heating the solid-state direct reduced iron and melting it in an electric furnace without introducing oxygen to separate into a molten steel and a slag, and continuously discharging the slag, and a decarburization including blowing, in the electric furnace, a total amount of oxygen introduced into the electric furnace to the molten steel to decarburize the molten steel after the slag separation.

The invention relates to a method for extracting metal from metal-containing raw material in a batch process by using a direct current electric arc furnace (100) having one or more than one top electrode (125) and at least one bottom electrode (115), wherein the method comprises the following steps: adding the metal-containing raw material to the furnace (100), thereby obtaining a loaded bath, moving the top electrode(s) (125) onto the raw material, heating the loaded bath in a heating step by applying direct current through the top electrode(s) to provide an arc to melt the raw material, thereby obtaining molten metal (202), wherein an average voltage during the heating step is from 20 V to 110 V, and forming solid metal from the molten metal (202). The invention further relates to a direct current electric arc furnace, a system comprising a direct current electric arc furnace, and a solid metal obtainable by the method.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

A production apparatus and method for electric arc furnace steelmaking with a fully continuous ultra-short process are provided. A continuous adding, melting, smelting and continuous casting of a metal material are integrated, and a metallurgy process is completed in a flowing of a molten steel, to realize a continuous production of ingot blanks. The production apparatus includes four operation sites of an electric arc furnace for melting and primary refining, a sealed tapping chute for molten steel flowing, a refinement storage bed for molten-steel desulfurization and alloying and a conticaster for continuous casting A material flow, an energy flow and a time stream in the four operation sites are in a dynamic equilibrium. The production apparatus and method realize a molten-steel casting is started within 120 minutes after the metal material is started to be continuously added, and an uninterrupted continuous production is maintained for above 80 hours.

A refining process control device includes: a past similar performance extraction unit configured to extract, from the refining performance database, a performance value of a past refining process in which a refining condition being a refining process condition acquired before the start of the refining process and including a result of an immediately preceding refining process in the refining facility, is similar to a refining process condition as a calculation target and the evaluation value is high; and an operation amount determination unit configured to determine an initial operation amount at the start of a refining process based on the performance value of the past refining process extracted by the past similar performance extraction unit, and determine an operation amount based on a change amount of the initial operation amount after the start of the refining process.

A method for efficiently manufacturing low-phosphorus molten steel by use of a steelmaking electric furnace, in which slag resulting from melting a solid iron source is effectively separated from molten steel, and thus a unit consumption of lime required to reduce a phosphorus content in the molten steel is reduced. The method includes: charging a solid iron source and an optional molten iron source and melting and heating these raw materials by using electric energy; partly or entirely removing slag generated during the melting; performing dephosphorization by adding dephosphorization flux; and tapping low-phosphorus molten steel thus refined, and in the method, a slag composition ratio being [CaO]/([SiO.sub.2]+[Al.sub.2O.sub.3]) of the slag to be removed is adjusted to be not less than 0.25 and not more than 0.70.

Additive for the thermochemical treatment of molten iron in order to separate, distribute, agglomerate, precipitate, spheroidize and/or crystallize combined, solvated and/or colloidal carbon present in molten iron in the liquid state into graphite in its hexagonal diamond or Lonsdaleite form, in order to produce ductile, nodular, spheroidal, vermicular, coral, spheroidized or grey iron with superior mechanical properties, iron with high metal yield and zero contraction during casting; the additive comprises two or more elements in the metallic state selected from the S-block of periods 2 to 7 of the periodic table of elements; and two or more elements in the metallic state selected from F-block of periods 6 to 7 of the periodic table of elements. The additive makes it possible to produce cast iron parts with Type I and II spheroidal graphite in hexagonal diamond or Lonsdaleite form as per the ASTM-A247 standard.

A production apparatus and method for electric arc furnace steelmaking with a fully continuous ultra-short process are provided. A continuous adding, melting, smelting and continuous casting of a metal material are integrated, and a metallurgy process is completed in a flowing of a molten steel, to realize a continuous production of ingot blanks. The production apparatus includes four operation sites of an electric arc furnace for melting and primary refining, a sealed tapping chute for molten steel flowing, a refinement storage bed for molten-steel desulfurization and alloying and a conticaster for continuous casting A material flow, an energy flow and a time stream in the four operation sites are in a dynamic equilibrium. The production apparatus and method realize a molten-steel casting is started within 120 minutes after the metal material is started to be continuously added, and an uninterrupted continuous production is maintained for above 80 hours.

A method for desulfurizing molten steel comprising taking a sample out from molten steel after tapping from a converter or during secondary refining and analyzing the sample rapidly with high accuracy by a method comprising a high frequency induction heating step wherein the sample is combusted and oxidized under the high frequency induction heating in an oxygen atmosphere having an oxygen purity of 99.5 vol % or more to convert S in the sample into SO.sub.2 and an analyzing step wherein SO.sub.2-containing gas produced in the high frequency induction heating step is analyzed through an ultraviolet fluorescence method to quantify S concentration of the sample.

Embodiments include a method of making steel with low carbon content which includes preparing a heat of molten steel composition in a steelmaking furnace to a tapping temperature ranging from 2912 to 3060 degrees F. and tapping into a ladle the molten steel composition having an oxygen level is about 700 to 1000 ppm. The molten steel composition is then transported to a ladle metallurgy furnace, where the molten steel composition is further heated and one or more elements are added to the molten steel composition. The molten steel composition is then transported from the ladle metallurgy furnace to a vacuum tank degasser. The molten steel composition is then decarburized and one or more elements are added to the molten steel composition at the vacuum tank degasser for deoxidization and desulphurization. The molten steel composition is then transported to a ladle metallurgy furnace to further adjust chemistry and temperature.