Direct treatment of reduced iron

Abstract

A method and apparatus for treating phosphorus-containing hydrogen-reduced DRI in an induction furnace are disclosed. The method includes the step of treating molten DRI by transferring at least partially the phosphorus in the DRI into slag, thereby obtaining an iron raw material having a lower phosphorus concentration (usually 0.03% by weight or less) that is at least substantially alpha iron and suitable for use as a direct feed material for producing steel in steelmaking equipment such as existing EAFs.

Description

Technical Field

[0001] The present invention relates to a method and an apparatus for processing hydrogen-reduced direct reduced iron (DRI) containing phosphorus (for example, in the form of phosphorus oxide) into a low-phosphorus iron raw material for steelmaking.

[0002] The present invention relates to, but is not limited to, a method and an apparatus particularly for processing (for example, batch processing) hydrogen-reduced direct reduced iron containing phosphorus in the form of phosphorus oxide (as a residue after the metallization process of DRI) using an induction melting furnace, wherein processing of such DRI produces an iron raw material suitable for use in existing steelmaking equipment.

[0003] Such iron raw material can then be directly supplied, for example in a molten state, as a hot metal raw material for conversion into steel of a desired grade to a steelmaking furnace, metal refining station or other steelmaking equipment; alternatively, after being cast as a solid iron raw material, it can be supplied as a "cold" iron raw material to a separate or remotely located steelmaking equipment.

[0004] As used herein, the term "steelmaking equipment" refers to a facility having one or more furnaces for steel production, including but not limited to the following furnaces: a) A furnace supplied with a molten bath of carbon-containing iron as described herein, in which molten iron in the entire molten bath is oxidized to FeO by blowing oxygen into the molten bath, while FeO is reduced back to Fe by conversion of carbon in the molten bath, thereby generating CO, and finally refining into the desired steel having a predetermined carbon content. Such a furnace is typically a basic oxygen furnace (BOF), also called an LD converter (derived from the city of Linz and the Donawitz district in Austria). This type of furnace can accept approximately 20 to 30% of the input metallic iron as cold iron raw material. b) A furnace that primarily feeds in "cold" metallic iron raw materials, melts them using an electric arc to form a molten steel bath, and adjusts the carbon concentration in the steel to the required level after the molten bath has been completely formed in the furnace. Such furnaces are typically electric arc furnaces (EAFs). These furnaces are usually fed mostly solid steel scrap, with higher purity metallic iron components added as needed to dilute undesirable trump elements (e.g., tin and copper that cannot be removed in the steelmaking process) arising from the scrap source. Such furnaces can also use iron raw materials as the primary metallic iron feed material instead of steel scrap. In some cases, EAFs are used in conjunction with ladle smelting furnaces, thereby separating the steel melting process in the EAF from the processing and refining processes to the final steel composition. The molten steel produced in the EAF is poured into a ladle, which serves as the reactor for the metallurgical process in the processing station.

[0005] In this specification, the term “steel” means an iron-carbon alloy in which the amount of carbon is greater than 0.008% but less than 2.06% by weight. While the term “steel” applies to iron-carbon alloys with a carbon content up to 2.06% by weight, it is rare for the carbon content to exceed 0.8% in ordinary commercially produced steel grades. It should also be noted that other alloying elements may be present, including those intentionally added to produce steel for special applications (e.g., manganese spring steel).

[0006] In this specification, the term "carbon-containing iron" means an iron-carbon alloy in which the total amount of carbon is 2.06% by weight or more and less than 4.3% by weight. Such iron may contain substantial amounts of other elements as a result of the reduction / smelting process leading to its manufacture.

[0007] In this specification, the term "alpha iron" means iron containing 0.008% by weight or less of carbon at room temperature, and containing a solid solution of carbon in pure iron. Such iron may contain other trace elements due to the reduction process that led to its manufacture.

[0008] In this specification, the term “iron raw material” means “alpha” iron and “steel,” and in either case, it is not limited by its physical state, but may be in a liquid or solid state.

[0009] In this specification, the term "hydrogen-reduced direct reduced iron" refers to an iron material produced by reducing iron ore at a temperature below the solid bulk melting temperature using a hydrogen-rich reducing agent, wherein the metallization rate of iron exceeds 95%.

[0010] In this specification, the term "hydrogen-rich reducing agent" means a gas that is a reducing agent containing 90% or more hydrogen as the element that combines with oxygen from iron oxides in iron ore. Such hydrogen is usually in the form of H2, but this does not preclude the use of synthesis gas formed from, for example, NH3, or mixtures of H2 with other gases such as CO or CH4.

[0011] In this specification, the term "metallization rate" refers to the degree to which iron oxides are converted to metallic iron during reduction, and is expressed as a percentage of the weight ratio of metallic iron to the total amount of iron. [Background technology]

[0012] The production of iron and steel has historically been a carbon-intensive process, typically using carbon from geologically derived carbonaceous materials, which is ultimately released into the atmosphere as CO2. With global efforts to reduce overall atmospheric CO2 emissions, steelmakers are required to find ways to produce iron and steel without net greenhouse gas emissions. In particular, they are required to avoid the use of geologically derived carbonaceous materials such as coal and natural gas—non-renewable resources collectively known as "fossil fuels"—as their use leads to increased concentrations of greenhouse gases in the atmosphere.

[0013] Currently, the majority of iron produced globally for the conversion to steel is produced using the blast furnace method, a technology that has existed since before the Industrial Revolution. Despite technological advancements, blast furnaces still require approximately 800 kg of coking coal to produce one ton of iron, and furthermore, they emit high levels of CO2, with approximately 1.8 to 2.2 tons of CO2 released per ton of molten iron. The need for fossil fuels, particularly coal (in the form of coke), is an essential supply for the operation of blast furnaces, and hydrogen cannot simply be used as a complete substitute for those fossil fuels.

[0014] As an alternative approach to iron production to blast furnaces, methods are known that use carbon monoxide and / or hydrogen obtained from natural gas or coal to reduce iron ore in a solid state. Although such plants are fewer in number than blast furnaces (except in India), numerous processes exist for the direct reduction of iron ore. In India, coal-based rotary kiln furnaces are used to produce DRI, or so-called sponge iron (accounting for about 20% of global DRI production), while in other regions, gas-based shaft furnace processes are dominant (accounting for about 80% of global DRI production).

[0015] Gas-based direct reduction plants often constitute part of an integrated steelmaking minimill located adjacent to an electric arc furnace (EAF) steelmaking plant, although some DRI is transported from on-site direct reduction plants (usually Midrex® or HYL® process-based) to remote steelmaking plants. Because such DRI is used directly in electric arc furnaces, there are stringent requirements regarding the levels of certain impurities in the DRI, such as phosphorus. This is because many impurities are difficult and costly to remove using EAFs. For this reason, the iron ore used in the production of DRI is often crushed and pulverized to micron-sized particles to remove gangue minerals. Such finely pulverized material can present challenges in its handling (both transport and operation). Therefore, this material is usually granulated with water and / or a binder to produce "green" balls of nearly uniform size, which are then dried and fed into a furnace to be calcined into hard pellets (this process is known as induction). The pellets are then supplied directly to the reduction plant as feedstock (or, in some cases, to the blast furnace as high-quality iron ore feedstock to help dilute the gangue of lump ore or sintered ore used by the blast furnace). The "green" balls that form the pellets have a compressive strength of approximately 10 N in a wet state and 50 N in a dry state. The pellets (after injection) have a compressive strength of approximately 2000 N.

[0016] The sponge iron production process implemented in India is primitive and not energy-efficient. The main raw materials are iron ore (size 5-18 mm), lumpy coal, and dolomite (size 4-8 mm, to prevent sulfur from coal from being incorporated into the sponge iron). The metallization rate of iron ore (Fe content 62-66 wt%) is typically lower than that of gas-based direct reduction plants. The metallization rate is estimated to range from 75% to a maximum of 90%, but is not determined (by grade) until the reduction process is complete, the sponge iron is cooled (using a rotary cooler connected to the kiln), and then the iron is separated by magnetism from the majority of non-magnetic materials such as ash and unreacted coal or ore. Since India has three grades defined as Grade I (metallization rate of 82% or more), Grade II (metallization rate of 78-82%), and Grade III (metallization rate of 76-78%), it is expected that the overall amount of slag produced will increase if lower grades are supplied to the induction furnace for steel production.

[0017] In metallurgical terminology related to iron or steel production, a process (or a particular step thereof) is commonly referred to as having or forming "acidic slag" or "basic slag." Here, "acidic" refers to slag where the main oxides are nonmetallic oxides such as SiO2 or P2O5, while "basic" refers to slag where the main oxides are metallic oxides such as FeO or CaO (lime). These reactions between acids and bases form compounds within the slag. Examples of such reactions include: CaO + SiO2 → CaSiO3 FeO + SiO2 → FeSiO3

[0018] Slag does not mix with the metal in the molten bath and, being lighter than the metal, tends to float above it. Slag can be intentionally acidic, basic, or neutral, largely depending on the flux added. Since the temperature of the molten bath usually does not exceed the melting point of the main components of typical gangue (often a mixture of aluminum and silicon oxides), it is desirable to add flux to react with the gangue and lower its melting point to a level where everything in the bath essentially melts. This makes the slag sufficiently fluid and easy to handle. The flux can be acidic, basic, or neutral. An example of a neutral flux is fluorite (CaF2). The most commonly used basic fluxes in steelmaking are limestone, which is essentially calcium carbonate, and dolomite, a mixture of calcium carbonate and magnesium carbonate. When these fluxes are added, they decompose into metal oxides, releasing carbon dioxide. However, in the steelmaking stage, it is more common to use pre-heated and decomposed lime (CaO) as a flux instead of limestone.

[0019] One currently proposed "green method," that is, a method for producing steel without using fossil fuels, using existing high-gane iron ore, is carried out through the production of DRI using hydrogen as a reducing agent. This is done, for example, through the reduction of iron ore powder in a fluidized bed system such as the injection pellet method or Metso Outotec's hydrogen-based Circored™ process, after which carbon-containing iron is produced by smelting in a special type of electric arc furnace, usually (but not necessarily) called a submerged arc furnace (SAF) or electric smelting furnace (ESF). In order to reduce carbon use / emissions as much as possible in such a route, it is necessary to convert renewable (green) energy into hydrogen (produced by electrolysis), especially during periods when the cost of wind / solar power is low, and to use that hydrogen to produce DRI, as well as to use renewable green energy to power the electric arc furnace. However, the final smelting step, by definition, requires a certain limited amount of carbon. Only high-grade DRI with extremely low levels of gangue and other impurities can be mixed with steel scrap and supplied to conventional EAFs for steelmaking.

[0020] Another proposed "green method," that is, steel production without the use of any fossil fuels, is carried out through the production of DRI using biomass as a reducing agent. The applicant's group companies have developed technology to produce biomass-reduced DRI from iron ore. This biomass technology includes the BioIron® process, which uses untreated biomass instead of coking coal as a reducing agent to convert iron ore into metallic iron for use in the steelmaking process. The patent portfolio of such technologies includes, for example, international patent applications PCT / AU2017 / 051163 (WO2018 / 076048), PCT / AU2021 / 050526 (WO2021 / 237308), PCT / AU2021 / 051094 (WO2022 / 061398), and PCT / AU2021 / 051398 (WO2022 / 109663).

[0021] In the following description, magnetite, hematite, and goethite are referred to as specific oxide forms of iron ore. In reality, there is a much greater diversity of geological iron ore types, and the use of such references should not be interpreted as limiting the forms of iron ore that can be treated with DRI, and consequently, the forms to which the present invention can be applied. Furthermore, they may exist in the same structure as geological minerals, and therefore, when the oxide forms of magnetite, hematite, and / or goethite are used herein, it merely indicates that they are predominantly of that mineral type. For example, the “taconite” iron ore described later contains magnetite as well as some hematite.

[0022] Regardless of the approach used to manufacture DRI, challenges may arise when processing that DRI in downstream processes within current steelmaking equipment.

[0023] For example, when DRI is produced from iron ore minerals that are essentially "magnetite," i.e., have an Fe3O4 composition, the problem is often not so serious. This is because impurities / gangues in the ore can generally be easily separated from the magnetite by crushing and sorting. As an example, in the United States, "taconite" iron ore, which is two-thirds silica by weight, requires crushing to separate the magnetite from the silica (by magnetic separation).

[0024] Currently, the majority of iron ore used in blast furnaces worldwide is based on the use of minerals whose composition is primarily "hematite" (Fe2O3) or "goethite" (FeO·OH). These ores, in addition to containing gangue components, tend to have several impurities that are more tightly bound in the oxide structure, and therefore grinding is of little effect in removing them. Furthermore, when goethite is used as a feedstock for pellets that are processed into DRI, it tends to cause decrepitation during the pellet hardening process (called infusion).

[0025] Therefore, only iron ore types with low gangue content (or those that can be easily graded to remove gangue) are naturally applicable to the DRI / EAF combination. The EAF process becomes less efficient when using materials with high gangue content, i.e., slag production increases and iron loss increases, making the use of DRI produced from high-gangue ore inherently uncompetitive.

[0026] Another important problem is that the DRI manufacturing process lacks a simple way to reduce the phosphorus content, an undesirable impurity both physically and chemically. Phosphorus is a major contaminant in steelmaking and, when present in the final steel, has a strong influence (much stronger than carbon) on the transition temperature at which the steel changes phases, and can cause the steel to become brittle during mechanical processing and heat treatment processes (Reference: "Physical Metallurgy Principles", 1964, RE Reed-Hill). For this reason, phosphorus should be avoided as much as possible in the iron ore supply material. In practice, it is possible to remove phosphorus in BOF / EAF steelmaking by forming a highly oxidizing slag (especially one containing high levels of FeO), but this method significantly slows down the manufacturing time of each batch of steel and involves the inevitable loss of iron into the slag, thus greatly increasing the cost of steel production.

[0027] For Indian steelmakers using induction furnaces, the situation is even more severe. In induction furnaces, due to the small ratio of furnace diameter to height, blowing oxygen into the molten bath to remove phosphorus (P) from steel is not easy, as this causes excessive metal loss. It is generally considered that high slag basicity and high oxygen potential in the molten bath are required to remove P. One approach recommended to steelmakers is to generate synthetic slag with high FeO and CaO contents. Such contents can be obtained by reusing BOF / LD slag as an intentional additive ("Phosphorous Control in Induction Furnace Steel melting using LD Slag", International Journal of Engineering Research & Technology (IJERT) Vol. 5 Issue 06, June-2016).

[0028] Iron ore miners other than those mining magnetite tend to mine iron ore with phosphorus levels as low as possible, but many ore deposits contain considerable amounts of phosphorus since they are formed under the sea or under wet conditions, so miners are forced to either sell such ore at a discount, or mix it with iron ore of lower phosphorus content to produce a uniform iron ore blend with acceptable phosphorus levels. Unfortunately, however, as ore deposits that have already been mined are becoming depleted, maintaining this current situation is gradually becoming more difficult.

[0029] Due to its melting approach, a blast furnace has the capability to remove most gangue and part of undesirable impurities as a component of slag, for example, Si (89%), titanium (77%), sulfur (80%), and potassium (73%) are removed (reference: "Modern Blast Furnace Ironmaking third edition", 2015, Maarten Geerdes et al). However, due to the strong reducibility of reactions in the blast furnace, undesirable elements such as phosphorus are reduced (from their oxide forms) and incorporated into the metal as part of the ironmaking process. In a blast furnace, the allowable phosphorus level in molten carbon-containing iron is controlled by blending a plurality of different iron ores as feed materials. In this process, usually some ores have an iron content higher or lower than that of the main ore supply, but have a low phosphorus content. Ores with higher iron content carry a price premium (due to limited availability), and when using iron ores with lower iron content, there are disadvantages that the energy efficiency per ton of metallized iron decreases (furthermore, when fossil fuels are used, CO₂ emissions increase).

[0030] Accordingly, it is an object to establish a method and an apparatus that can convert DRI containing a considerable amount of phosphorus, for example in the form of phosphorus oxide, into a desirable iron raw material without transferring phosphorus as an impurity. When DRI is smelted as part of the process (that is, in a state where melting and reduction reactions occur simultaneously under high temperature and high reduction conditions), phosphorus is highly likely to migrate into the iron raw material.

[0031] The above description should not be construed as an admission of common general knowledge in Australia or any other country. Summary of the Invention

[0032] This invention is based on the recognition that furnaces using electric arcs (in any form) or other types of steelmaking equipment are not necessarily the optimal approach for preparing iron raw materials for steelmaking using hydrogen-reduced DRI, which is a feedstock originating from iron ore with a phosphorus content of more than 0.07% by weight.

[0033] This invention is based on the recognition that, in at least some circumstances, it is a more preferable approach to treat hydrogen-reduced direct iron reduction (DRI) containing phosphorus using an induction furnace and then reduce the phosphorus concentration of the DRI after this treatment to a concentration suitable for direct steelmaking in steelmaking equipment such as an EAF. Typically, this means reducing the phosphorus concentration to 0.03% by weight or less.

[0034] In this specification, the term "induction furnace" refers to an electromagnetic furnace in which heat is applied by induction heating of a metal. The capacity of induction furnaces varies from less than 1 kg to more than 100 tons. An induction furnace generates a rapidly changing alternating magnetic field that penetrates the conductive material to be heated, thereby generating eddy currents and causing Joule heating of the material.

[0035] In a broad sense, the present invention relates to a method and apparatus for treating phosphorus-containing hydrogen-reduced DRI, such as phosphorus oxide (as a residue after a DRI metallization process), in an induction furnace. This treatment includes the step of treating molten DRI by transferring / distributing the phosphorus in the DRI into the slag, thereby obtaining an iron raw material with a lower phosphorus concentration that is at least substantially alpha iron and suitable for use as a direct feed material for producing steel in existing steelmaking equipment, such as EAFs.

[0036] In a broad sense, the present invention provides a method for producing iron raw materials suitable for direct steel formation in a steelmaking apparatus, having a phosphorus concentration (usually 0.03% by weight or less) suitable for direct steel formation in a steelmaking apparatus, from hydrogen-reduced DRI having a higher phosphorus concentration, using an electromagnetic induction furnace. (a) A step of melting hydrogen-reduced DRI in the chamber of an induction furnace using a magnetic field induced in the chamber to form a molten DRI-containing bath, (b) A step of forming a basic slag in the chamber that transfers phosphorus in the molten DRI to the slag at least partially, thereby converting the molten DRI into a molten iron raw material which is at least substantially alpha iron and has a phosphorus concentration (usually 0.03% by weight or less) suitable for directly forming steel in a steelmaking apparatus, (c) The process includes the step of removing at least a portion of the iron raw material from the furnace, for example by tapping.

[0037] This invention provides a method for producing iron raw materials suitable for direct steel formation in a steelmaking apparatus, having a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically less than 0.03% by weight, from hydrogen-reduced DRI with a high phosphorus concentration, using an electromagnetic induction furnace. (a) A step of supplying hydrogen-reduced supply DRI into the induction reactor chamber, (b) The steps of operating an induction furnace to melt the DRI with a magnetic field induced in the chamber and to form a molten DRI-containing bath, (c) A step of forming a basic slag in the chamber that transfers at least partially the phosphorus in the molten DRI to the slag, thereby converting the molten DRI into a molten iron raw material which is at least substantially alpha iron and has a phosphorus concentration suitable for directly forming steel in a steelmaking apparatus, usually 0.03% by weight or less. (d) The step of removing at least a portion of the slag from the furnace, for example by tapping or scraping, (e) The step of removing at least a portion of the iron raw material from the furnace, either at the same time as or at a different time from removing the slag from the furnace, for example by tapping.

[0038] Hydrogen-reduced DRI can have a phosphorus concentration exceeding 0.07% by weight.

[0039] This method may include a step of first selecting a slag composition and then controlling the slag composition during the implementation of the method to achieve any composition suitable for promoting the transfer of phosphorus from the molten DRI into the slag.

[0040] Options for controlling slag composition include the use of slag-forming additives to impart the desired slag basicity, and the selection of the operating temperature within the induction furnace.

[0041] This method may include controlling the slag basicity to less than 3, usually less than 2, where slag basicity is defined as the ratio of basic oxides to acidic oxides in the molten slag, and is usually expressed as the ratio of (CaO% + MgO%) / SiO2% of the molten slag.

[0042] This method may include controlling the FeO concentration in the slag composition to a range of 5 to 20% by weight during the implementation of this method.

[0043] This method may include controlling the FeO concentration in the slag composition to less than 10% by weight during the implementation of this method.

[0044] This method may include controlling the ratio of CaO to SiO2 in the slag composition to less than 2.0% by weight during the implementation of this method.

[0045] This method may include controlling the ratio of CaO to SiO2 in the slag composition to less than 1.5% by weight during the implementation of this method.

[0046] This method may include controlling the ratio of MgO to Al2O3 in the slag composition to 0.4 to 0.6 during the implementation of this method.

[0047] This method typically involves maintaining the slag composition with FeO at 5% by weight, a CaO-to-SiO2 ratio of 1.5, and a MgO-to-Al2O3 ratio of 0.5.

[0048] This method may include controlling the slag composition during its implementation by adding slag-forming materials. Slag-forming materials such as CaO and MgO may be present in the DRI, and these may affect the amount of these materials that need to be added separately during the implementation of this method.

[0049] This method may include maintaining the molten bath at a temperature of 1540°C.

[0050] This method may include forming a molten bath at a temperature up to 20°C higher than the liquidus temperature of alpha iron.

[0051] This method may include forming a molten bath at a temperature up to 30°C higher than the liquidus temperature of alpha iron.

[0052] This method may include forming a molten bath at a temperature up to 40°C higher than the liquidus temperature of alpha iron.

[0053] This method may include forming a molten bath at a temperature up to 60°C higher than the liquidus temperature of alpha iron.

[0054] This method may include forming a molten bath at a temperature not exceeding 90°C higher than the liquidus temperature of alpha iron.

[0055] This method may include forming a molten bath at a temperature not exceeding 80°C higher than the liquidus temperature of alpha iron.

[0056] In this specification, the term "liquidus temperature of alpha iron" means the temperature at which all reduced iron in DRI becomes liquid, and the temperature at which all iron that can or does combine with carbon during the melting process, i.e., Fe3C, becomes liquid.

[0057] This method may include stirring or otherwise mixing the molten metal (rather than mixing the molten slag and molten metal) within the induction furnace.

[0058] This method can be controlled so that at least two-thirds of the phosphorus in the supplied DRI is transferred to the slag.

[0059] This method can be controlled so that at least three-quarters of the phosphorus in the supplied DRI is transferred to the slag.

[0060] This method may include supplying the DRI to the induction furnace at a high temperature (above room temperature).

[0061] This method may include supplying the DRI to the induction furnace at a temperature of at least 400°C.

[0062] This method may include supplying the DRI to the induction furnace at a temperature of at least 600°C.

[0063] This method may include supplying the DRI to the induction reactor under an oxygen-free environment.

[0064] In this specification, "oxygen-free" means a state of substantially or extremely oxygen-deficient conditions.

[0065] This method may include supplying the DRI to the induction reactor as DRI with a metallization rate of at least 97%.

[0066] This method may include supplying the DRI to the induction reactor as DRI with a metallization rate of at least 99%.

[0067] This method can be operated in batch, continuous, or semi-continuous mode.

[0068] This method can be operated in a batch system, and molten iron raw materials are sequentially generated as continuous batches within the induction furnace.

[0069] The batch method may include performing steps (a) to (e) described above after forming a heel of molten iron raw material or other suitable molten material in the furnace.

[0070] This method may include periodically removing the molten slag and molten iron raw material, for example by tapping, after a complete melting state has been formed in the furnace.

[0071] In this specification, the term "complete melting" means the stage in this method in which all of the molten supply material has melted.

[0072] This method may include periodically removing the molten slag, for example by tapping, before a complete molten state is formed in the furnace, maintaining the remaining slag in the furnace to desired properties, and ensuring fluidity for tapping the slag.

[0073] In this specification, the term “desired property” means a property that facilitates the transfer of phosphorus to slag in DRI.

[0074] This method may include gradually introducing the supplied DRI into the furnace along with the necessary slag-forming material and melting it at a temperature close to the liquidus temperature of the DRI. This makes it possible to avoid bath temperatures that are significantly higher than the liquidus temperature of alpha iron.

[0075] Ca and / or Mg-containing slag-forming material may be intentionally added to the furnace as needed, or it may be largely obtained by being added as a raw material in advance during the DRI production process and subsequently introduced into the induction furnace together with the supply DRI.

[0076] This method may include forming DRI from iron ore using a hydrogen-rich reducing agent in one or more fluidized bed processes. The fluidized bed process may be any suitable process.

[0077] Hydrogen is typically the only reducing agent to which hydrogen is intentionally added.

[0078] The iron ore used in the formation of hydrogen-reduced DRI may be in the form of fine iron ore powder.

[0079] In this specification, the term "iron ore fine powder" means iron ore fragments of a size that can pass through a suitable screen mesh with an opening of 4 mm or less. The term "iron ore fine powder" does not imply that all particles are crushed or broken down to the point where they can pass through a 1 mm screen. Preferably, all iron ore fine powder passes through a 2 mm screen.

[0080] This method may include adding carbon to the molten bath to carburize the iron raw material.

[0081] This method may include operating multiple induction furnaces and producing iron raw materials using this method.

[0082] Typically, this method involves operating multiple induction furnaces, allowing other furnaces to continue operating even if one or more furnaces are undergoing maintenance / refractory relining.

[0083] This method may include casting molten iron raw material directly into ingots and using them as "cold feed" to steelmaking equipment in subsequent processes.

[0084] This method may include heating the molten iron raw material before removing it from the induction furnace (for example by tapping) and after removing the slag (for example by tapping), thereby imparting a degree of superheating to the molten iron raw material that is sufficient to be poured into a transport container such as a ladle for remote casting or further downstream processing.

[0085] The degree of superheating may be at least 50°C higher than the liquidus temperature of the molten iron raw material. Further downstream processing may include adding carbon and other additives at a ladle transfer station to produce steel, followed by casting. Such casting can be carried out in various conventional forms, such as slab casting, billet casting, or ingot casting.

[0086] Alternatively, the method may include removing the slag from the induction furnace (e.g., by tapping), converting the alpha iron in the molten iron raw material into steel by adding carbon and other alloying additives to the molten material to form molten steel, and then removing the molten steel (e.g., by tapping) while it is still superheated enough to be poured into a transport container such as a ladle for remote casting or further downstream processing.

[0087] The degree of superheating may be at least 50°C higher than the liquidus temperature of a particular grade of steel.

[0088] In this specification, the term "degree of superheating" means the difference between the temperature of the molten material and the temperature at which such material begins to solidify.

[0089] The present invention also provides an apparatus for producing iron raw material suitable for direct steel formation in a steelmaking apparatus, having a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically 0.03% by weight or less, from hydrogen-reduced DRI using an electromagnetic induction furnace. The induction furnace is configured to melt the DRI with a magnetic field induced in the induction furnace to form a bath of molten DRI and molten basic slag, the slag having a composition that can at least partially transfer phosphorus from the molten DRI, thereby processing the molten DRI in the furnace to form molten iron raw material that is at least substantially alpha iron, having a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically 0.03% by weight or less. The induction furnace includes a chamber for melting and processing the DRI, an inlet for supplying the DRI into the chamber, an outlet for discharging the slag from the chamber, and an outlet for discharging the molten iron raw material from the chamber.

[0090] Furthermore, the present invention provides a steelmaking method that includes the step of producing steel using a steelmaking apparatus described herein from an iron raw material having a phosphorus concentration (usually 0.03% by weight or less) suitable for direct steel formation in a steelmaking apparatus, obtained by the above-described method for producing an iron raw material from hydrogen-reduced DRI.

[0091] Hydrogen-reduced DRI can contain phosphorus at a concentration exceeding 0.07% by weight.

[0092] The present invention relates to a steelmaking method, (a) A step of producing hydrogen-reduced DRI from iron ore having a phosphorus concentration of more than 0.07% by weight in a DRI production apparatus, (b) A step of melting and processing the DRI in an induction furnace and transferring the phosphorus in the DRI to the slag in the induction furnace, thereby reducing the phosphorus concentration of the DRI to a concentration suitable for direct steel formation in a steelmaking apparatus, usually 0.03% by weight or less, while controlling the temperature in the furnace so as not to exceed 90°C above the liquidus temperature of the DRI, and making the processed DRI a raw material for iron which is at least substantially alpha iron, (c) A steelmaking method comprising the step of manufacturing steel from iron raw materials using a steelmaking apparatus.

[0093] This method may include maintaining the temperature inside the furnace not to exceed 90°C above the liquidus temperature of the DRI until at least the majority of the slag has been removed from the furnace by tapping or scraping.

[0094] In one embodiment, the DRI manufacturing apparatus, induction furnace, and steelmaking apparatus may be located in separate locations that are spaced apart from each other.

[0095] In that case, the steelmaking method may include the steps of: producing compressed briquettes of hydrogen-reduced DRI produced in a DRI production apparatus; transferring the compressed briquettes to an induction furnace while they are still at a high temperature; producing iron raw materials from hydrogen-reduced DRI in an induction furnace; casting or granulating the iron raw materials; transferring the cast or granulated iron raw materials to a steelmaking apparatus; and producing steel from the iron raw materials in a steelmaking apparatus.

[0096] In another embodiment, the DRI manufacturing apparatus and the induction furnace may be located in close proximity, while the steelmaking apparatus may be located in a separate location, separated from the DRI manufacturing apparatus and the induction furnace.

[0097] In that case, the steelmaking method may include the steps of: producing iron raw materials in a DRI manufacturing apparatus and an induction furnace; casting or granulating the iron raw materials; transferring the iron raw materials to a steelmaking apparatus; and producing steel from the iron raw materials in the steelmaking apparatus.

[0098] In another embodiment, the induction furnace and steelmaking equipment may be located in close proximity to each other in a separate location, away from the DRI manufacturing equipment, while the DRI manufacturing equipment is located in the same location.

[0099] In that case, the steelmaking method may include the steps of: producing compressed briquettes of hydrogen-reduced DRI produced in a DRI production apparatus; transferring the briquettes to an induction furnace while they are still at a high temperature; producing iron raw materials from hydrogen-reduced DRI in the induction furnace; and producing steel from the iron raw materials in a steelmaking apparatus.

[0100] Furthermore, the steelmaking method may include the step of directly transferring the molten iron raw material from the induction furnace to the steelmaking apparatus.

[0101] The DRI manufacturing equipment, induction furnace, and steelmaking equipment may be part of an integrated steelmaking system.

[0102] In that case, the steelmaking method may include the steps of: producing hydrogen-reduced DRI in a DRI production apparatus; transferring the DRI to an induction furnace; producing iron raw materials from the hydrogen-reduced DRI in the induction furnace; transferring the iron raw materials to a steelmaking apparatus; and producing steel from the iron raw materials in the steelmaking apparatus.

[0103] The steelmaking method may include the step of transferring hydrogen-reduced DRI (hydrogen-reduced ribolytic resin) directly from the DRI production apparatus to an induction furnace as a receiving material or its compressed briquettes while it is still at a high temperature.

[0104] Alternatively or additionally, the steelmaking method may include the step of directly transferring the iron raw material in a molten state from an induction furnace to a steelmaking apparatus.

[0105] The DRI manufacturing apparatus may be an apparatus for manufacturing hydrogen-reduced DRI as described in the aforementioned international application in the name of the present applicant.

[0106] The iron raw material production apparatus may be the apparatus described above.

[0107] The steelmaking equipment may be any suitable equipment such as an EAF. [Brief explanation of the drawing]

[0108] The present invention will be described in more detail by reference to the accompanying drawings. [Figure 1] Figure 1 shows one embodiment of a method and apparatus for manufacturing steel according to the present invention. [Figure 2] Figure 2 shows one embodiment of an apparatus for producing iron from hydrogen-reduced iron (DRI) according to the present invention. [Figure 3] Figures 3(a), 3(b), and 3(c) show one embodiment of the method for producing iron from hydrogen-reduced iron (DRI) according to the present invention. [Figure 4]Figures 4(a), 4(b), 4(c), and 4(d) illustrate another embodiment (but not the only other embodiment) of the method for producing iron from hydrogen-reduced iron (DRI) according to the present invention. [Modes for carrying out the invention]

[0109] As described above, the present invention, in a broad sense, is a method and apparatus for processing hydrogen-reduced DRI that still contains phosphorus, for example, hydrogen-reduced DRI containing phosphorus in the form of phosphorus oxide (as a residue after the DRI metallization process), in an induction melting furnace. This process includes the steps of melting the DRI and transferring at least partially the phosphorus in the DRI into the slag to produce an iron raw material from the DRI with a lower phosphorus concentration that is suitable for use as a direct feed material to existing steelmaking equipment, such as an EAF.

[0110] In essence, the present invention provides a "link" between hydrogen-reduced DRI and existing steelmaking equipment, such as EAFs, with respect to phosphorus concentration. The present invention provides an opportunity to make hydrogen-reduced DRI a practical feed material in existing steelmaking equipment.

[0111] Therefore, this invention is important from the standpoint of realizing "green" steelmaking.

[0112] Referring to Figure 1, one embodiment of the method and apparatus for manufacturing steel according to the present invention is: (a) A step in which a hydrogen-reduced DRI is produced from iron ore powder and hydrogen in a DRI production apparatus 3 (usually having a phosphorus concentration of more than 0.07% by weight and a metallization rate of at least 95% by weight), (b) A step of transferring the hydrogen-reduced DRI as the supply DRI to the induction reactor 5, usually at a temperature of at least 400°C, (c) A step of producing a molten iron raw material that is at least substantially alpha iron and usually has a phosphorus concentration of 0.03% by weight or less by melting and processing hydrogen-reduced DRI in a furnace to reduce the phosphorus concentration in the DRI to 0.03% by weight or less, (d) A step of transferring the molten iron raw material, normally in a molten state, to the steelmaking apparatus 7, (e) The step of manufacturing steel in a steelmaking apparatus 7.

[0113] The induction furnace 5 may be any suitable induction furnace for producing molten iron raw material for steelmaking from hydrogen-reduced iron (DRI).

[0114] The steelmaking apparatus 7 may be any suitable apparatus such as an EAF, and may include, for example, an EAF and its associated ladle smelting furnace.

[0115] In another embodiment of the present invention (but not the only other embodiment), the induction furnace 5 has a dual function: to produce molten iron raw material having a low phosphorus concentration (typically 0.03% by weight or less), and subsequently to process the raw material to produce steel or an intermediate raw material for steelmaking. For example, the method may include a step of carburizing and heating the molten iron raw material to form an intermediate steelmaking raw material having a selected carbon concentration suitable for steelmaking.

[0116] One embodiment of an induction furnace 5 for producing molten iron from hydrogen-reduced iron (DRI), shown in Figure 2, comprises a bottom 9 and side walls 11 lined with refractory material, and a removable refractory-lined lid (not shown). The induction furnace 5 includes an induction coil 13 within the side wall 11 of the furnace. This coil is connected to an AC power source (not shown).

[0117] The refractory material may be any suitable material.

[0118] The induction reactor 5 may be of any suitable size.

[0119] Figures 3 and 4 show two of several embodiments of the method for producing iron raw materials for steelmaking from hydrogen-reduced iron (DRI) according to the present invention, using an embodiment of the induction furnace 5 shown in Figure 2.

[0120] In these embodiments, the induction furnace 5 can accommodate approximately 3 tons of molten metal and slag. The present invention is not limited to this furnace capacity.

[0121] Although the embodiments shown in Figures 3 and 4 are operated in a batch manner, the present invention is not limited to batch operation.

[0122] With respect to Figure 3(a), the first step of this embodiment is to form a heel 15 of molten metal in the induction furnace 5. The molten metal may be, for example, a portion of the molten iron raw material produced in the previous batch in the induction furnace. The molten metal may be molten iron raw material produced in another induction furnace. The molten metal may be molten iron raw material produced in a suitable dedicated furnace.

[0123] The next step is to introduce the hydrogen-reduced supply DRI as a solid into the induction furnace 5, usually at a high temperature. Typically, the supply DRI has a phosphorus concentration exceeding 0.07 wt% and a metallization rate of at least 95%. In the embodiment shown in Figure 3, the supply DRI is introduced in a single batch, a method of introduction well known to those skilled in the art. In other embodiments, the supply DRI may be introduced into the induction furnace 5 in a series of small batches or in smaller, continuous feeds by any suitable means, a method of introduction well known to those skilled in the art.

[0124] The induction furnace 5 heats and melts the supply DRI, and the heel 15 of the molten metal ensures heat transfer in the initial stages of the method.

[0125] During the melting step, slag-forming material, which is normally solid, is added to the induction furnace 5 to form molten basic slag (usually slag basicity < 2), thereby facilitating the transfer of phosphorus and other impurities from the DRI to the slag. The slag-forming material can be supplied to the induction furnace 5 by any suitable means, either as a single batch, a series of small batches, or as a continuous supply of smaller amounts, and such supply methods are also well known to those skilled in the art. The total amount of slag-forming material is adjusted taking into account the amount of slag-forming material already present in the supply DRI.

[0126] While the supplied DRI and solid slag-forming materials are melting, and after they have melted, phosphorus and other impurities in the DRI are transferred to the slag layer 17, thereby reducing the phosphorus concentration in the molten DRI.

[0127] The composition of the molten DRI and molten slag in the induction furnace 5 is monitored at least periodically to evaluate the chemical composition (such as phosphorus concentration) and other factors (such as slag basicity), and the amount of slag-forming material added and the operating temperature are adjusted as needed.

[0128] After the molten DRI in the induction furnace 5 reaches the target phosphorus concentration, the molten metal becomes a suitable iron raw material for steelmaking, essentially alpha iron, with a high metallization rate and a low phosphorus concentration (usually less than 0.3% by weight). At this point, the slag is tapped, and then the iron raw material is tapped and transferred to a steelmaking apparatus (not shown).

[0129] Figure 3(b) conceptually shows the induction furnace 5 during the melting step of this method, where a heel 15 of molten metal is present in the lower section of the induction furnace 5, a layer of molten slag 17 is present in the upper section of the induction furnace 5, and a layer of partially processed new molten metal 19 is formed between the heel 15 and the slag layer 17.

[0130] The "new" metal in layer 19 is molten DRI with a lower phosphorus concentration than the supply DRI, as a result of phosphorus migration to the slag layer 17.

[0131] It should be noted that, in practice, the heel 15 and the new molten metal layer 19 do not become separate layers with a clear interface between them. The molten metal within those layers mixes. This mixing may occur due to the movement of metal caused by the magnetic and electric fields within the induction furnace 5, or it may occur due to a mechanical mixing device (not shown).

[0132] Figure 3(c) conceptually shows the induction furnace 5 at the end of the method after the molten slag layer 15 has been tapped out of the induction furnace 5. The new layer of molten metal 19 is tapped into a ladle or other suitable molten metal transfer means and transferred to the steelmaking furnace 7 (Figure 1). As a preliminary step before tapping the molten metal, the molten metal may be heated and carburized by the addition of graphite as a pretreatment for steelmaking in the steelmaking furnace 7. The heel 15 of the remaining molten metal is held in the induction furnace 5 for use in processing the next batch of feed DRI. This holding of the heel 15 is indicated by arrow 21.

[0133] As in the case of Figure 3(b), in reality, the heel 15 and the new molten metal layer 19 do not become separate layers with a clear interface between them. The molten metal within those layers mixes. This mixing may occur due to the movement of metal caused by the magnetic and electric fields within the induction furnace 5, or it may occur due to a mechanical mixing device (not shown).

[0134] The embodiment of the method shown in Figure 4 is substantially the same as the embodiment in Figure 3. The main difference is that in the embodiment of Figure 4, the hydrogen reduction DRI is introduced into the induction reactor 5 in two stages. This two-stage introduction is shown in Figures 4(b) and 4(c).

[0135] This invention is based on research and development, including the following tests, conducted by a group company of the applicant.

[0136] Laboratory-scale tests were conducted on hydrogen-reduced DRIs with the compositions shown below, using the applicant's induction reactor located in Bandura, Victoria, Australia. The following examples report some of the results of those tests.

[0137] Example 1 Cold hydrogen-reduced DRI was mixed with flux (CaO and MgO added to achieve a target CaO / SiO2 ratio of 1.5 and an MgO / Al2O3 ratio of 0.5) and graphite (2.5%) (partially to suppress the oxidation of Fe to FeO). This mixture was placed in a crucible, the induction furnace was powered on, and the output was increased until the DRI / mixture melted. The temperature was monitored during this process. After melting, a slag sample was taken by sucking up the slag using a steel rod, and a metal sample was taken using a quartz tube. The chemical composition of the samples is shown below.

[0138] Chemical composition (weight %) of hydrogen-reduced DRI: Fe (total iron): 91.5% (metallization rate 94%) P: 0.17% Al2O#: 1.48% SiO2: 2.25%

[0139] Chemical composition of slag (weight %): FeO: 5.3% Basicity: 1.58 P2O5: 0.46% C: 0.02% Al2O3: 18.5% SiO2: 25.5% CaO: 35.0% MgO: 7.3%

[0140] Chemical composition of molten iron (weight %): C: 0.4% P: 0.02% Si: 0.01% Mn: <0.01% Al: <0.01% Ca: 0.01% S: 0.01%

[0141] As is clear from the above chemical composition, the phosphorus in the DRI is substantially transferred into the slag, and the resulting iron raw material has a low phosphorus concentration (0.02% by weight).

[0142] Example 2 Cold hydrogen-reduced DRI (metallization rate 98%, Pilbara blend DRI) was mixed with flux (CaO and MgO added to achieve a target CaO / SiO2 ratio of 1.5 and an MgO / Al2O3 ratio of 0.5), but unlike Example 1, no carbon source was added. This mixture was placed in a crucible, the induction furnace was powered on, and the output was increased until the DRI / flux melted at a temperature of approximately 1540°C. At this point, the molten iron was just in the liquid phase.

[0143] The temperature was monitored throughout this process. After melting, a steel rod was used to suck up the slag and collect a slag sample, and a quartz tube was used to collect a metal sample. The metal bath was basically collected shortly after everything had melted.

[0144] The chemical composition (by weight %) of the sample molten iron was as follows: P: 0.02% C: <0.005% Fe: remainder

[0145] The phosphorus concentration of 0.02% by weight in the molten iron is the same as the phosphorus concentration in the molten iron in other tests where a small amount of carbon was added (carbon concentration in the molten iron was 0.4%) (see Example 1). As in Example 1, from the chemical composition of the molten iron described above, and from what can be inferred therefrom, it is clear that the phosphorus in the DRI is substantially transferred into the slag, and the resulting iron raw material has a low phosphorus concentration (0.02% by weight).

[0146] The above results support the present invention. In particular, the above results demonstrate that it is possible to melt and process hydrogen-reduced DRI and transfer phosphorus into the slag.

[0147] Furthermore, many modifications can be made to the embodiments of the present invention described above without departing from the spirit and scope of the invention.

[0148] For example, in the embodiment shown in Figure 1, the DRI is transferred to the induction furnace 5 at a temperature of at least 400°C, but the present invention is not limited thereto and includes embodiments in which the DRI is transferred at higher or lower temperatures.

[0149] Furthermore, in the embodiment shown in Figure 1, molten iron is transferred from the induction furnace 5 to the steelmaking apparatus 7, but the present invention is not limited to this and also includes embodiments in which the iron is in solid form.

[0150] Furthermore, while the embodiment of induction furnace 5 in Figure 2 includes a bottom and side walls lined with refractory material, a removable refractory-lined lid, and induction coils within the furnace walls, the present invention is not limited thereto and includes any suitable form of induction furnace.

[0151] Furthermore, although the embodiments of the method described with respect to Figures 3 and 4 are operated in a batch manner, the present invention is not limited thereto, and the method may also be operated in a continuous or semi-continuous manner.

[0152] For example, a continuous / semi-continuous method involves using a channel-type induction furnace in which the filling and tapping operations can proceed simultaneously. Such furnaces may be equipped with a rearward tilt function to facilitate the removal of slag from the bath surface. This type of furnace (at least for general processing of molten iron) is supplied by companies such as Otto Junker GmbH.

[0153] Furthermore, while embodiments of the present invention describe the treatment of iron ore as a starting material for DRI production, it should be noted that the present invention also includes the treatment of any other suitable iron oxide-containing material.

Claims

1. A method for producing an iron raw material having a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically less than 0.03% by weight, from hydrogen-reduced DRI with a higher phosphorus concentration, using an electromagnetic induction furnace, (a) A step of supplying hydrogen-reduced supply DRI into the chamber of the induction reactor, (b) The steps of operating the induction furnace and melting the DRI with a magnetic field induced in the chamber to form a bath containing molten DRI, (c) A basic slag is formed in the chamber to transfer at least partially the phosphorus in the molten DRI to the slag, thereby converting the molten DRI into a molten iron raw material which is at least substantially alpha iron and has a phosphorus concentration suitable for directly forming steel in a steelmaking apparatus, usually 0.03% by weight or less. (d) The step of removing at least a portion of the slag from the furnace by tapping or scraping, (e) A method characterized by comprising the step of removing at least a portion of the iron raw material from the furnace at the same time as or at a different time from removing the slag from the furnace by tapping or the like.

2. In the method according to claim 1, A method characterized by first selecting a slag composition, and then, during the execution of the method, controlling the slag composition to be any composition suitable for promoting the transfer of phosphorus from molten DRI to the slag.

3. In the method according to claim 1 or 2, A method characterized by including controlling the FeO concentration in the slag composition to a range of 5 to 20% by weight during the implementation of the method.

4. In the method according to claim 3, A method characterized by including controlling the FeO concentration in the slag composition to less than 10% by weight during the implementation of the method.

5. In the method described in any one of the preceding claims, During the implementation of this method, CaO and SiO in the slag composition ２ The ratio (CaO / SiO ２ A method characterized by controlling ) to less than 2.

0.

6. In the method described in any one of the preceding claims, During the implementation of this method, MgO and Al in the slag composition ２ O ３ The ratio (MgO / Al ２ O ３ A method characterized by controlling ) to 0.4 to 0.

6.

7. In the method described in any one of the preceding claims, 5 wt% of FeO, CaO and SiO ２ _{2} ratio (CaO / SiO ２ _{2}) is 1.5, the ratio of MgO to Al ２ _{2}O ３ _{3} (MgO / Al ２ _{2}O ３ _{3}) is 0.5, the slag composition is maintained. A method characterized in that.

8. In the method described in any one of the preceding claims, A method characterized by maintaining the molten bath at a temperature of 1540°C.

9. In the method described in any one of the preceding claims, A method characterized by forming a molten bath at a temperature up to 20°C higher than the liquidus temperature of alpha iron.

10. In the method described in any one of the preceding claims, A method characterized by forming a molten bath at a temperature up to 30°C higher than the liquidus temperature of alpha iron.

11. In the method described in any one of the preceding claims, A method characterized by forming a molten bath at a temperature not exceeding 90°C higher than the liquidus temperature of alpha iron.

12. In the method described in any one of the preceding claims, A method characterized by forming a molten bath at a temperature not exceeding 80°C higher than the liquidus temperature of alpha iron.

13. In the method described in any one of the preceding claims, A method characterized by controlling the method such that at least two-thirds of the phosphorus in the supplied DRI is transferred to the slag.

14. In the method described in any one of the preceding claims, A method characterized by supplying the DRI to the furnace at a high temperature of at least 400°C.

15. In the method described in any one of the preceding claims, A method characterized by supplying the supplied DRI to the furnace as DRI having a metallization rate of at least 97%.

16. In the method described in any one of the preceding claims, A method characterized by being operated in a batch system, in which a continuous batch of molten iron raw material is formed.

17. In the method according to claim 16, A method characterized by forming a heel of molten iron raw material in the furnace, followed by performing steps (a) to (e).

18. In the method described in any one of the preceding claims, A method characterized by periodically removing molten slag and molten iron raw material after a completely molten state has been formed in the furnace.

19. In the method according to any one of claims 1 to 17, A method characterized by periodically removing molten slag before a completely molten state is formed in the furnace, maintaining the remaining slag in the furnace to desired properties, and ensuring fluidity for slag tapping.

20. In the method described in any one of the preceding claims, A method characterized by supplying DRI into the furnace in stages along with the necessary slag-forming material, and melting the DRI using a bath temperature that is sufficiently above the liquidus temperature of alpha iron.

21. In the method described in any one of the preceding claims, A method characterized by operating multiple induction furnaces and producing iron raw materials by this method.

22. In the method described in any one of the preceding claims, A method characterized by directly casting molten iron raw material into ingots and using them as "cold supply" to steelmaking equipment in subsequent processes.

23. In the method described in any one of the preceding claims, A method characterized by heating the molten iron raw material before removing it from the induction furnace (for example by tapping) and after removing the slag (for example by tapping), thereby imparting a degree of superheating to the molten iron raw material that is sufficient to be poured into a transport container such as a ladle for remote casting or further downstream processing.

24. In the method described in any one of the preceding claims, A method characterized by removing slag from an induction furnace (for example by tapping), converting alpha iron, a raw material for molten iron, into steel by adding carbon and other alloying additives to the molten material to form molten steel, and then removing the molten steel (for example by tapping) while it is superheated to a degree sufficient for pouring into a transport container such as a ladle for remote casting or further downstream processing.

25. An apparatus for producing iron raw materials having a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically 0.03% by weight or less, from hydrogen-reduced DRI using an electromagnetic induction furnace, The induction furnace is configured to melt the DRI by a magnetic field induced within the induction furnace, forming a bath of molten DRI and molten basic slag. The slag has a composition that can transfer at least partially phosphorus from the molten DRI, thereby processing the molten DRI in the furnace to form a molten iron raw material that is at least substantially alpha iron and has a phosphorus concentration suitable for direct steel formation in a steelmaking apparatus, typically 0.03% by weight or less. The apparatus is characterized in that the furnace includes a chamber for melting and processing DRI, an inlet for supplying DRI into the chamber, an outlet for discharging slag from the chamber, and an outlet for discharging molten iron raw material from the chamber.

26. A steelmaking method that includes a step of manufacturing steel from iron raw materials using a steelmaking apparatus, A steelmaking method characterized in that the iron raw material has a phosphorus concentration suitable for directly forming steel in the steelmaking apparatus, usually a phosphorus concentration of 0.03% by weight or less, and is produced by the method for producing an iron raw material from hydrogen-reduced DRI as described in any one of claims 1 to 24.

27. In the method according to claim 26, The method is characterized in that the hydrogen-reduced DRI contains phosphorus at a concentration of more than 0.07% by weight.

28. A steelmaking method, (a) A step of producing hydrogen-reduced DRI from iron ore having a phosphorus concentration of more than 0.07% by weight in a DRI manufacturing apparatus, (b) A step of melting and processing DRI in an induction furnace, transferring phosphorus in the DRI to the slag in the furnace, thereby controlling the temperature in the furnace so as not to exceed 90°C above the liquidus temperature of the DRI, reducing the phosphorus concentration of the DRI to a concentration suitable for direct steel formation in a steelmaking apparatus, usually 0.03% by weight or less, and using the processed DRI as an iron raw material that is at least substantially alpha iron, (c) A steelmaking method characterized by comprising the step of manufacturing steel from iron raw materials using a steelmaking apparatus.

29. In the steelmaking method according to claim 28, A steelmaking method characterized by maintaining the temperature inside the induction furnace not to exceed 90°C above the liquidus temperature of the DRI until at least the majority of the slag is removed from the furnace by tapping or scraping.

30. In the method according to claim 28 or 29, A steelmaking method characterized in that, when the DRI manufacturing apparatus, the induction furnace, and the steelmaking apparatus are each located in separate locations separated from each other, the steelmaking method includes the steps of: manufacturing compressed briquettes of hydrogen-reduced DRI manufactured in the DRI manufacturing apparatus; transferring the compressed briquettes to the induction furnace while they are still at a high temperature; manufacturing iron raw materials from hydrogen-reduced DRI in the induction furnace; casting or granulating the iron raw materials; transferring the cast or granulated iron raw materials to the steelmaking apparatus; and manufacturing steel from the iron raw materials in the steelmaking apparatus.

31. In the steelmaking method according to claim 28 or 29, A steelmaking method characterized in that, when the DRI manufacturing apparatus and the induction furnace are located in close proximity to each other, and the steelmaking apparatus is located in a separate location separated from the DRI manufacturing apparatus and the induction furnace, the steelmaking method includes the steps of: manufacturing iron raw materials in the DRI manufacturing apparatus and the induction furnace; casting or granulating the iron raw materials; transferring the iron raw materials to the steelmaking apparatus; and manufacturing steel from the iron raw materials in the steelmaking apparatus.

32. In the steelmaking method according to claim 28 or 29, A steelmaking method characterized in that, when the DRI manufacturing apparatus is located in the same location as the induction furnace and the steelmaking apparatus are located in close proximity to each other in separate locations separated from the DRI manufacturing apparatus, the steelmaking method includes the steps of: producing compressed briquettes of hydrogen-reduced DRI produced in the DRI manufacturing apparatus; transferring the briquettes to the induction furnace while they are still at a high temperature; producing iron raw materials from the hydrogen-reduced DRI in the induction furnace; and producing steel from the iron raw materials in the steelmaking apparatus.

33. In the steelmaking method according to claim 28 or 29, A steelmaking method characterized in that, when the DRI manufacturing apparatus, the induction furnace, and the steelmaking apparatus are part of an integrated steelmaking apparatus, the steelmaking method includes the steps of: manufacturing hydrogen-reduced DRI in the DRI manufacturing apparatus; transferring the DRI to the induction furnace; manufacturing iron raw materials from the hydrogen-reduced DRI in the induction furnace; transferring the iron raw materials to the steelmaking apparatus; and manufacturing steel from the iron raw materials in the steelmaking apparatus.

34. In the steelmaking method described in claim 33, A steelmaking method characterized by including the step of directly transferring hydrogen-reduced DRI from the DRI manufacturing apparatus to the induction furnace at a high temperature.

35. In the steelmaking method according to claim 33 or 34, A steelmaking method characterized by including the step of directly transferring iron raw materials from the induction furnace to the steelmaking apparatus while at a high temperature.

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