Method and apparatus for the production of metals, alloys, matte, or concentrated and refined slag from primarily oxide raw materials

Abstract

Steel-making systems and methods are described, as well as furnaces and methods for producing steel using such furnaces. In some embodiments, the furnace can include a shell having an upper portion and a lower portion. There can also be a roof connected to the upper portion, which can have a feed port for introducing metal oxides into the furnace. The shell can include an injector capable of injecting a fluid into the furnace. The lower portion can be connected to a hearth. The furnace can melt metal oxides to form a molten bath in the hearth. The molten bath can have a slag layer and a metal layer. The fluid can reduce the metal oxides in the slag layer to form molten metal.

Description

[Technical Field]

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims the benefit of U.S. Provisional Patent Application No. 63 / 391,679, filed July 22, 2022, the entire contents of which are incorporated herein by reference.

[0002] Technical Field The present disclosure relates generally to the production of metals, alloys, including steel and iron alloys, matte, and concentrated or refined slag from primarily oxide feedstocks, and methods for producing metals, alloys, matte, and concentrated and refined slag, and more particularly to integrated processes that include smelting reduction furnaces and methods for using such furnaces to produce metals, alloys, matte, and concentrated and refined slag with reduced CO2 emissions compared to coal-based processes. [Background technology]

[0003] Primarily oxide raw materials, sometimes in a molten state, are used as raw materials to produce a variety of metals, alloys, mattes, and concentrated or refined slags. Metals produced from oxide and / or carbonate raw materials include tin, lead, iron, chromium, and silicon. Alloys produced from oxide and / or carbonate raw materials include steel, ferrous alloys such as iron-chromium, iron-nickel, and iron-silicon, and non-ferrous alloys such as brass and bronze. Matte produced from oxide and / or carbonate raw materials includes copper, nickel, and cobalt matte for subsequent processing. Concentrated and refined slags produced from oxide and / or carbonate raw materials include titania slag for subsequent production of titanium dioxide powder, and slag from oxidation processes such as flash smelting for copper and nickel production, steelmaking processes, or highly reduced slag fume processes.

[0004] As an example of an existing process for producing steel from primarily oxide feedstocks, primary steel is primarily produced in a blast furnace (BF) by converting agglomerated iron ore into molten carbon-rich pig iron, or hot metal, which is then converted into steel in a basic oxygen furnace (BOF) and subsequent ladle metallurgy refining processes before casting. Approximately 75% of steel is produced in blast furnaces and basic oxygen furnaces, and approximately 1.85 tonnes of CO2 (t co2 / t cs ) to 2.2t co2 / t cs Steel production generates approximately 11% of the world's total CO2 emissions. The conversion of iron ore to molten steel via the BF-BOF route requires five steps, including coking and preparing the iron ore by sintering or pelletizing. The blast furnace is the most carbon-intensive step in the primary steelmaking process. In another step, coal is converted into metallurgical coke, which is then fed into the blast furnace to reduce the iron ore, and the heat required for melting is provided by combustion with hot air blown into the furnace. At the bottom of the blast furnace, molten iron metal collects, with slag floating on top of the carbonized metallic iron. The slag layer is composed of gangue elements present in the iron ore. While it is possible to inject hydrogen into the blast furnace to replace some of the coke, this process is not optimized for direct hydrogen reduction, resulting in low hydrogen utilization, minimal CO2 emission reduction (approximately 20%), and a significant negative impact on the thermal profile of the BF. In the downstream BOF process, high-purity oxygen is injected into the hot metal to reduce the carbon content of the hot metal from BF from 3-4% to 1%, remove unwanted impurities, and refine the pig iron and scrap steel to the required composition for steel.

[0005] An alternative technology for producing virgin iron is the direct reduction of iron (DRI) in a shaft furnace or fluidized-bed reactor using carbon monoxide and hydrogen as the reducing gas mixture. Typically, the source of the reducing gas mixture is natural gas or coal. Depending on the specific DRI process, iron ore pellets or fine iron ore particles are directly reduced in the solid state in the DRI reactor. The reaction temperature in the DRI process is much lower than the melting point of iron, typically below approximately 800 °C to avoid sintering and agglomeration problems of the iron ore pellets. This process produces a highly reactive and porous solid product, sponge iron, which must be used in adjacent steel production processes to avoid excessive reoxidation, or pressed while still hot to produce hot-formed iron (HBI), which can be shipped worldwide.

[0006] While commercialization efforts are underway to replace the carbon monoxide and hydrogen mixture with pure hydrogen in DRI processes, most technologies aim to include some carbon monoxide or a carbon source such as natural gas or methane to exothermically heat the endothermic reaction of molecular hydrogen with iron oxides and / or at least partially carbonize the DRI / HBI product so that the carbon becomes a "fuel" for partial removal downstream for steelmaking.

[0007] DRI / HBI must be melted and converted into steel in either a BOF or an electric arc furnace (EAF). EAFs use an electric arc to melt input materials, such as DRI / HBI, cast pig iron ingots (or pig iron), and scrap steel, maintaining a molten slag layer on top and a metal layer on the bottom during subsequent refining to produce steel. EAFs are typically used to process scrap iron into secondary steel, and DRI / HBI or cast pig iron are used to dilute impurities in the scrap iron that limit the grade of steel produced in secondary steelmaking. However, some EAFs now primarily use DRI / HBI with some cast pig iron to produce higher-quality steel for more demanding applications. To make DRI / HBI compatible with existing EAF processes and technologies, high-grade iron ore, typically containing 65+% iron, must be used in the DRI process, limiting the amount of gangue elements present in the DRI / HBI. In DRI, because the process occurs in the solid state, gangue elements such as silicon and aluminum in oxide form are not removed as a separate slag phase as in BF or BOF. Also, the degree of iron metallization in DRI is generally limited to about 90%, and the remaining unreduced iron remains in the DRI as wüstite (FeO), which also forms slag upon melting. Therefore, the molten-phase oxidation process that occurs in EAF or BOF can produce very large amounts of slag if the DRI contains a high concentration of gangue and if the slag contains a high concentration of FeO due to the chemical equilibrium between the steel and slag produced by the oxidation of carbon in the iron-based phase.

[0008] Recently, it has been proposed to add a melting furnace between the DRI process and the EAF or BOF, such as the large submerged arc furnace (SAF) used by New Zealand Steel. This additional furnace would melt the DRI and separate gangue elements and any remaining unreduced FeO from the metallic iron. To produce molten pig iron and a low-iron slag that is compatible with existing steelmaking processes, a sufficient amount of reducing agent would need to be added to the melting furnace. Currently, the reducing agent is some form of solid carbon. Much of this carbon is blown away from the pig iron to form steel, resulting in GHG emissions.

[0009] One example of an existing process for producing metals from primarily oxide feedstocks is the reduction and smelting of tin concentrates, primarily containing cassiterite, to produce crude tin and waste slag using a multi-step process involving smelting, slag reduction, and slag fuming. Top-submerged lance (TSL) furnaces have replaced reverberatory and electrosmelting furnace technologies as the dominant technology for tin production. Silicon metal and many iron alloys are primarily produced by smelting and reducing oxide feedstocks in large EAFs. These processes include calcination and / or pre-reduction steps prior to the EAF. Ferrochromium production has transitioned from alternating current (AC) furnace technology (typically operated in either submerged arc or brush arc mode) to direct current (DC) furnaces because chromium recovery is improved when chromium ore is reduced in DC furnaces. Matte is commonly produced in smelting reduction furnaces when processing slightly sulfided ores, as occurs in some Indonesian nickel laterite smelters, when smelting calcined concentrates with residual sulfur content, or when reducing slags high in copper, nickel, or cobalt from upstream oxidation pyrometallurgical processes. Titanium ores can be upgraded by removing iron in a reduction smelting process that involves preheating the ore and forming a reduction char in a rotary kiln, as occurs in Canada, South Africa, Norway, and China. Molten slag can also be refined by reducing dissolved oxide species to a molten collecting phase below the slag, or by reducing or evaporating dissolved oxide species to a furnace freeboard gas phase above the slag. Examples include reduced slags high in cobalt or silver, and reduced slags high in zinc, lead, and tin.

[0010] The hydrogen plasma smelting reaction (HPSR) described herein is a smelting reduction reaction that utilizes the high temperatures of ionized hydrogen and hydrogen plasma, and molecular hydrogen gas injected into the molten slag layer or the molten phase below the molten slag, to produce a molten alloy, matte, or vapor phase from a metal oxide mixture, or a mixture primarily of metal oxides with some sulfur content. The ionized hydrogen and molecular hydrogen gas create highly reducing conditions within the molten slag and / or surrounding environment, enabling many chemical reduction reactions to occur. While these reactions may be less favorable in the presence of molecular hydrogen, the ionized hydrogen shifts the Gibbs free energy of the reaction to more favorable thermodynamic conditions. Additionally, the main furnace described herein also includes embodiments that use an electric arc to generate thermal energy for smelting, since molecular hydrogen and / or hydrogen plasma are used in metal oxide reduction reactions.

[0011] When applied to steel production, HPSR contributes to a method for producing steel from iron ore with minimal CO2 emissions by utilizing the ionized state of hydrogen to reduce iron ore. Compared to the reduction of iron ore with neutral species (e.g., molecular hydrogen from DRI), the reduction potential of hydrogen ions is 3 to 15 times higher. The reduction of iron ore with hydrogen plasma and / or molecular hydrogen allows for process simplification, with the option to produce molten steel from iron ore in a single furnace, eliminating the need for two separate processes (reduction and refining) and the need for iron ore pre-agglomeration, pelleting, or upgrading. Therefore, HPSR furnaces developed to date inject hydrogen gas through a plasma torch, into an ambient gas environment, through the furnace's upper shell, or through the center of the electrode. Existing HPSR furnaces introduce iron ore through the center of the electrode for in-flight reduction or at the bottom of the furnace in a batch process, limiting the surface area for the reduction reaction and therefore limiting process throughput. Summary of the Invention

[0012] This disclosure relates to the production of metals, alloys, matte, and concentrated or refined slag, including the production of the aforementioned metals and alloys (e.g., copper, iron, steel, iron chromium, nickel, etc.). While the description herein is of a furnace and method for using such a furnace for producing steel, the method is applicable to the production of other alloys, metals, matte, and refined slag, as will be understood by those skilled in the art. Iron ore or metal oxide in fine, sinter, or lump form can be added to the furnace through one or more feed ports in the furnace roof and / or furnace wall (e.g., shell). Feed ports can be located not only next to the electrodes but also around the roof. This configuration allows the hot zone within the furnace to be aligned with the iron ore or metal oxide feed path, which can increase productivity and reduce operating costs, and also helps protect the furnace walls from arc radiation and molten pool splashes. In some embodiments, the furnace can be operated with continuous tapping or batch tapping, thereby improving energy efficiency. In some embodiments, the furnace components described herein may be compatible with commercially available EAFs, which may be retrofitted with these components to perform HPSR and / or molecular hydrogen reduction reactions.

[0013] In some embodiments, a reducing fluid (e.g., hydrogen) can be injected through or near the electrodes to generate a hydrogen plasma. In some embodiments, hydrogen can be injected and / or bubbled from the bottom of the furnace. In some embodiments, hydrogen can be injected through supersonic or coherent jets located at the top and sides of the furnace. In some embodiments, hydrogen can enter the slag and molten metal bath regions of the furnace where reduction reactions can occur. These hydrogen injection modes can increase the reduction reaction area and create bath agitation, thereby improving the reduction reaction rate and hydrogen utilization. When hydrogen is injected into the metal and / or slag layers, the hydrogen jets can diffuse into hydrogen bubbles. Hydrogen injection modes can be selected to maximize hydrogen bubble dispersion, optimize the hydrogen bubble diameter to increase the reduction reaction surface area between the metal oxide and hydrogen, and / or optionally create a foamy slag, which maximizes the volume in which the reduction reaction occurs. Additionally, creating a foamy slag through hydrogen injection can protect the furnace roof from radiation from the molten bath, thereby reducing heat loss from the system. In some embodiments, a partial hydrogen atmosphere is created in the furnace by injected molecular hydrogen or a hydrogen mixture. The electric arc ionizes the hydrogen, creating a hydrogen plasma that can participate in metal oxide reduction reactions.

[0014] In some embodiments, a furnace for producing molten metal includes a shell or a plurality of walls having an upper portion and a lower portion, the shell or the plurality of walls including a plurality of injectors configured to inject a fluid into the furnace, a roof connected to the upper portion of the shell or the plurality of walls, the shell, the plurality of walls, and / or the roof including a plurality of feed ports configured to introduce a metal oxide into the furnace, and a hearth connected to the lower portion of the shell or the plurality of walls, the furnace configured to melt the metal oxide to form a molten bath including a slag layer including the molten metal oxide and a metal layer below the slag layer including the molten metal, and the fluid reduces the molten metal oxide in the slag layer to molten metal. In some embodiments, the plurality of injectors are configured to inject the fluid toward a working region of the molten bath where the metal oxide is present. In some embodiments, a first injector of the plurality of injectors is configured to inject the fluid toward a region of the molten bath. In some embodiments, a second injector of the plurality of injectors is configured to inject the fluid toward a second region of the molten bath different from the first region of the molten bath. In some embodiments, at least one of the plurality of injectors is configured to inject fluid into the molten bath. In some embodiments, at least one of the plurality of injectors is configured to inject fluid into a slag layer of the molten bath. In some embodiments, at least one of the plurality of injectors is an injector immersed in the molten bath. In some embodiments, at least one of the plurality of injectors is an injector immersed in the slag layer. In some embodiments, at least one of the plurality of injectors is an injector immersed in the molten bath in contact with both the slag layer and the metal layer. In some embodiments, the shell or plurality of walls has an internal axis, and the plurality of injectors are configured to inject fluid at an angle less than 90 degrees with respect to a line tangent to each injector in a cross section of the shell or plurality of walls perpendicular to the internal axis. In some embodiments, the roof includes a second plurality of injectors configured to inject fluid into the furnace.In some embodiments, the multiple injectors are configured to inject fluid such that the fluid stirs the slag and / or metal layers in the furnace. In some embodiments, the multiple injectors are configured to inject fluid such that the slag and / or metal layers of the molten bath swirl within the furnace. In some embodiments, the multiple injectors are evenly spaced around the circumference of the shell or multiple walls. In some embodiments, the fluid includes hydrogen gas, a hydrogen-containing gas, a carbon-containing gas, or a combination thereof. In some embodiments, the multiple injectors include at least one of a lance, a submerged tuyere, a swirling lance such as a top submerged lance, a supersonic jet, a coherent jet, a plasma torch, or any type of injector that maximizes the contact area between the injected fluid and the slag layer. In some embodiments, the plasma torch injects the fluid at a temperature higher than the melting point of the metal oxide. In some embodiments, the coherent jet includes at least one of a supersonic coherent jet, a subsonic coherent jet, or a coherent jet with a shrouded flame. In some embodiments, the roof includes at least one electrode extending from the roof toward the hearth of the furnace, the hearth includes at least one counter electrode, and the furnace is configured to generate an electric arc between a distal end of the at least one electrode and the at least one counter electrode. In some embodiments, the electric arc is between the distal end of the at least one electrode and a molten bath of the furnace. In some embodiments, the distal end of the at least one electrode is above a slag layer of the molten bath. In some embodiments, the distal end of the at least one electrode is immersed in the slag and / or metal layer of the molten bath. In some embodiments, the at least one counter electrode is embedded in the hearth. In some embodiments, the electric arc is a transferred electric arc or a non-transferred electric arc. In some embodiments, the electric arc is configured to melt metal oxides. In some embodiments, under AC or DC electrical operation, at any given time, at least one electrode is a cathode and at least one counter electrode is an anode.In some embodiments, at least one electrode includes a port passing through a central axis of the at least one electrode. In some embodiments, fluid is injected into the furnace through the port of the at least one electrode. In some embodiments, the electrodes are solid, and fluid is injected only through multiple injectors. In some embodiments, at least a portion of the fluid injected into the furnace passes through an electric arc that forms a plasma. In some embodiments, the plasma melts metal oxides, maintains the metal and slag layers in a molten phase, provides thermal energy to the furnace, provides ionized gas to the bath, and / or reduces metal oxides. In some embodiments, the roof includes multiple electrodes extending from the roof toward the hearth of the furnace, and the furnace is configured to generate an electric arc between a distal end of each electrode of the multiple electrodes and at least one counter electrode. In some embodiments, the distance between the multiple electrodes is such that no arc interference occurs between the electric arc of each electrode and at least one counter electrode. In some embodiments, the distance between the multiple electrodes is such that arc interference occurs between the electric arc of each electrode and at least one counter electrode, and the arcs converge toward the center of the bath. In some embodiments, at least one electrode and / or at least one counter electrode comprises graphite, titanium, tungsten, tantalum, zirconium, or copper. In some embodiments, an electric arc stirs the molten bath. In some embodiments, the multiple feed ports are configured so that feed ports closer to the center of the roof introduce more metal oxide into the furnace than feed ports further from the center of the roof. In some embodiments, in embodiments where ionized hydrogen and / or molecular hydrogen is present, the application of metal oxides such as iron oxide, chromium oxide, nickel oxide, copper oxide, and phosphorus oxide to the method is determined by their thermodynamic potential for reduction by the injected fluid and / or ionized fluid. In some embodiments, the metal oxide comprises iron oxide, hematite, magnetite, or a combination thereof. In some embodiments, the molten metal comprises metallic iron. In some embodiments, the shell or multiple walls comprise at least one heat exchanger.In some embodiments, at least one heat exchanger includes water cooling. In some embodiments, the shell or multiple walls include water-cooled copper. In some embodiments, the interior of the shell or multiple walls includes a castable refractory lining or other cutting-edge technology for enhancing furnace integrity. In some embodiments, the multiple injectors are configured to inject a flux source or metal oxide into the furnace. In some embodiments, the fluid is injected in combination with a solid, such as a flux or fine metal oxide, and the flux or injected metal oxide acts as a nucleation point for the injected gas, increasing the surface area for reaction between the fluid and the metal oxide in the slag layer. In some embodiments, the multiple injectors are configured to inject a carbon source into the furnace. In some embodiments, the carbon source is a solid carbon source. In some embodiments, the solid carbon source is injected into a metal bath for carbonization. In some embodiments, carbonization of the molten metal is performed in a downstream ladle metallurgy process.

[0015] In some embodiments, a method for forming molten metal includes introducing a metal oxide or metal mixture into a furnace through multiple feed ports in the roof and / or side of the furnace, melting the metal oxide in the furnace to form a molten bath including a slag layer containing molten metal oxide and a metal layer containing molten metal below the slag layer, and introducing a fluid into the furnace through multiple injectors on the side of the furnace, where the fluid reduces the molten metal oxide in the slag layer to molten metal. In some embodiments, the fluid is introduced toward adjacent injectors and / or adjacent working areas. In some embodiments, the fluid is introduced toward adjacent injectors and / or adjacent working areas. In some embodiments, the fluid is introduced into the molten bath. In some embodiments, the fluid is introduced into the slag layer of the molten bath. In some embodiments, the fluid is introduced into the metal layer of the molten bath, where the viscosity of the metal layer is lower than that of the slag layer, thereby reducing the diameter of bubbles formed from the injected fluid. In some embodiments, the fluid is introduced at an angle less than 90 degrees with respect to a line tangent to each injector in a cross section of the shell or multiple walls perpendicular to the interior axis. In some embodiments, the fluid is introduced to stir the molten bath in the furnace to produce a homogeneous slag composition and promote separation of the metals contained in the slag, so that the metals collect in a metal layer below the slag layer. In some embodiments, the fluid is introduced to swirl the molten bath in the furnace. In some embodiments, the multiple injectors are equally spaced around the circumference of the shell or multiple walls. In some embodiments, the fluid comprises hydrogen gas. In some embodiments, the method includes generating an electric arc between a distal end of at least one electrode extending from the furnace roof toward a lower portion of the furnace and at least one counter electrode in the lower portion of the furnace, the electric arc being configured to melt metal oxides or provide thermal energy to the bath. In some embodiments, the electric arc is between the distal end of the at least one electrode and the molten bath in the furnace. In some embodiments, the method includes introducing the fluid into the furnace through a port through a central axis of the at least one electrode. In some embodiments, the method includes generating a plasma from the introduced fluid and the electric arc.In some embodiments, an electric arc stirs the molten bath. In some embodiments, the method includes introducing more metal oxide into the furnace through a feed port closer to the center of the roof than through a feed port further from the center of the roof. In some embodiments, the metal oxide includes iron ore. In some embodiments, the metal oxide includes iron oxide, hematite, magnetite, an iron oxide-containing waste stream, or a combination thereof. In some embodiments, the iron ore is in the form of fines, lumps, pellets, sinter, and / or a metal oxide mixture. In some embodiments, the molten metal includes metallic iron. In some embodiments, the method includes introducing a carbon source into the furnace through multiple feed ports and / or multiple injectors. In some embodiments, the carbon source is a solid carbon source and is used to carbonize the metallic iron. In some embodiments, any fluid injected into the slag layer partially flows out without reducing the iron ore. In some embodiments, the fluid flowing out of the slag layer generates a plasma around the electric arc. In some embodiments, ionized fluid around the electric arc is drawn into the slag layer by the momentum of the arc. In some embodiments, the ionized fluid reduces metal oxides in the slag layer near the arc. In some embodiments, the ionized fluid around the electric arc becomes deionized and contributes to heat generation in the furnace by generating heat. In some embodiments, the furnace is a DC or AC electric arc furnace. In some embodiments, the method operates in a batch mode, a continuous mode, or a semi-continuous mode. In some embodiments, metal is continuously tapped, and a high-metal-oxide-containing slag can be processed batchwise by increasing fluid injection to reduce the metal oxides in the slag. In some embodiments, a first furnace produces a high-metal-oxide-containing slag and metal layer, and a second furnace is in communication with the first furnace to receive the slag. In some embodiments, the second furnace includes a method for reducing metal oxides contained in the slag. In some embodiments, the reduction reaction is carried out primarily at a high concentration of metal oxides in the slag layer to enhance hydrogen utilization in the process.In some embodiments, before tapping the slag, the injection rate of the reducing agent is increased to reduce the level of metal oxides in the slag before tapping.

[0016] In some embodiments, a furnace for producing molten metal includes a shell or a plurality of walls having a top and a bottom, the shell or the plurality of walls including a plurality of injectors configured to inject a fluid into the furnace; a roof connected to the top of the shell or the plurality of walls, the shell or the plurality of walls and / or the roof including a plurality of feed ports configured to introduce molten metal oxide into the furnace; and a hearth connected to the bottom of the shell or the plurality of walls, the furnace configured to maintain the molten metal oxide in a molten state, and the fluid reduces the molten metal oxide to molten metal. In some embodiments, the plurality of injectors are configured to inject the fluid toward the molten metal oxide. In some embodiments, a first injector of the plurality of injectors is configured to inject the fluid toward a region of the molten metal oxide. In some embodiments, a second injector of the plurality of injectors is configured to inject the fluid toward a second region of the molten metal oxide different from the first region of the molten metal oxide. In some embodiments, at least one of the plurality of injectors is configured to inject the fluid into the molten metal oxide. In some embodiments, at least one of the plurality of injectors is an injector submerged in the molten metal oxide. In some embodiments, at least one of the plurality of injectors is an injector submerged in the molten metal. In some embodiments, at least one of the plurality of injectors is an injector submerged in contact with both the molten metal oxide and the molten metal. In some embodiments, the shell or plurality of walls has an internal axis, and the plurality of injectors are configured to inject fluid at an angle less than 90 degrees relative to a line tangent to each injector in a cross section of the shell or plurality of walls perpendicular to the internal axis. In some embodiments, the roof comprises a second plurality of injectors configured to inject fluid into the furnace. In some embodiments, the plurality of injectors are configured to inject fluid such that the fluid stirs the molten metal oxide and / or molten metal in the furnace. In some embodiments, the plurality of injectors are configured to inject fluid such that the molten metal oxide and / or molten metal swirls within the furnace.In some embodiments, the multiple injectors are evenly spaced around the circumference of the shell or multiple walls. In some embodiments, the fluid includes hydrogen gas, a hydrogen-containing gas, a carbon-containing gas, or a combination thereof. In some embodiments, the multiple injectors include at least one of a lance, a submerged tuyere, a swirl lance such as a top submerged lance, a supersonic jet, a coherent jet, a plasma torch, or any type of injector that maximizes the contact area between the injected fluid and the slag layer. In some embodiments, the plasma torch injects the fluid at a temperature higher than the melting point of the metal oxide. In some embodiments, the coherent jet includes at least one of a supersonic coherent jet, a subsonic coherent jet, or a coherent jet with a shrouded flame. In some embodiments, the roof includes at least one electrode extending from the roof toward the hearth of the furnace, the hearth includes at least one counter electrode, and the furnace is configured to generate an electric arc between a distal end of the at least one electrode and the at least one counter electrode. In some embodiments, the electric arc is between the distal end of at least one electrode and the molten metal oxide and / or molten metal in the furnace. In some embodiments, the distal end of at least one electrode is above the molten metal oxide. In some embodiments, the distal end of at least one electrode is immersed in the molten metal oxide and / or molten metal. In some embodiments, at least one counter electrode is embedded in the hearth. In some embodiments, the electric arc is a transferred electric arc or a non-transferred electric arc. In some embodiments, under AC or DC electrical operation, at any given time, at least one electrode is a cathode and at least one counter electrode is an anode. In some embodiments, at least one electrode includes a port through the central axis of the at least one electrode. In some embodiments, a fluid is injected into the furnace through the port in the at least one electrode. In some embodiments, the electrode is solid, and the fluid is injected only through multiple injectors. In some embodiments, at least a portion of the fluid injected into the furnace passes through the electric arc to form a plasma.In some embodiments, the plasma maintains the molten metal oxide and / or molten metal in a molten state, provides thermal energy to the furnace, provides an ionized gas to the molten metal oxide and / or molten metal, and / or reduces the molten metal oxide. In some embodiments, the roof includes a plurality of electrodes extending from the roof toward the hearth of the furnace, and the furnace is configured to generate an electric arc between a distal end of each of the plurality of electrodes and at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that no arc interference occurs between the electric arc of each electrode and at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that arc interference occurs between the electric arc of each electrode and at least one counter electrode, and the arcs converge toward the center of the molten metal oxide. In some embodiments, at least one electrode and / or at least one counter electrode comprises graphite, titanium, tungsten, tantalum, zirconium, or copper. In some embodiments, the electric arc stirs the molten metal oxide. In some embodiments, the multiple feed ports are configured such that feed ports closer to the center of the roof introduce more molten metal oxide into the furnace than feed ports further from the center of the roof. In some embodiments, the applicability of the molten metal oxide is determined by the thermodynamic potential of reduction by the injected fluid and / or ionized fluid, such as iron oxide, chromium oxide, nickel oxide, copper oxide, and phosphorus oxide in embodiments where ionized hydrogen and / or molecular hydrogen are present. In some embodiments, the molten metal oxide comprises iron oxide, hematite, magnetite, or a combination thereof. In some embodiments, the molten metal comprises metallic iron. In some embodiments, the shell or multiple walls comprise at least one heat exchanger. In some embodiments, the at least one heat exchanger comprises water cooling. In some embodiments, the shell or multiple walls comprise water-cooled copper. In some embodiments, the interior of the shell or multiple walls comprises a castable refractory lining or other cutting-edge technology for enhancing furnace integrity.In some embodiments, the multiple injectors are configured to inject a flux source or metal oxide into the furnace. In some embodiments, the fluid is injected in combination with a solid, such as a flux or finely divided metal oxide, and the flux or injected metal oxide acts as a nucleation point for the injected gas, increasing the surface area for reaction between the fluid and the metal oxide in the slag layer. In some embodiments, the multiple injectors are configured to inject a carbon source into the furnace. In some embodiments, the carbon source is a solid carbon source. In some embodiments, the solid carbon source is injected into a metal bath for carbonization. In some embodiments, carbonization of the molten metal is performed in a downstream ladle metallurgy process.

[0017] In some embodiments, a method includes introducing molten metal oxide into a furnace through multiple feed ports in the roof and / or side of the furnace, maintaining the molten metal oxide in the furnace in a molten state, and introducing a fluid into the furnace through multiple injectors in the side of the furnace, where the fluid reduces the molten metal oxide to molten metal. In some embodiments, the fluid is introduced in a direction toward the molten metal oxide in the furnace. In some embodiments, the fluid is introduced toward an adjacent injector. In some embodiments, the fluid is introduced into the molten metal oxide. In some embodiments, the fluid is introduced into the molten metal, which has a lower viscosity than the molten metal oxide, thereby reducing the diameter of bubbles formed from the injected fluid. In some embodiments, the fluid is introduced at an angle of less than 90° perpendicular to the interior axis with respect to a line tangent to each injector in a cross section of the shell or multiple walls. In some embodiments, the fluid is introduced to agitate the molten metal oxide in the furnace to produce a homogeneous slag composition and promote separation of the metals contained in the slag, so that the metals collect in a metal layer below the slag layer. In some embodiments, the fluid is introduced to swirl the molten metal oxide within the furnace. In some embodiments, the multiple injectors are evenly spaced around the circumference of the shell or multiple walls. In some embodiments, the fluid includes hydrogen and / or carbon. In some embodiments, the method includes generating an electric arc between a distal end of at least one electrode extending from the roof of the furnace toward a lower portion of the furnace and at least one counter electrode in the lower portion of the furnace, the electric arc being configured to supply thermal energy to the bath. In some embodiments, the electric arc is between the distal end of the at least one electrode and the molten metal oxide and / or molten metal in the furnace. In some embodiments, the method includes introducing a fluid into the furnace through a port through a central axis of the at least one electrode. In some embodiments, the method includes generating a plasma from the introduced fluid and the electric arc. In some embodiments, the electric arc stirs the molten metal oxide and / or molten metal.In some embodiments, the method includes introducing more molten metal oxide into the furnace through a feed port closer to the center of the roof than through a feed port further from the center of the roof. In some embodiments, the molten metal oxide includes iron ore. In some embodiments, the molten metal oxide includes iron oxide, hematite, magnetite, an iron oxide-containing waste stream, or a combination thereof. In some embodiments, the molten metal includes metallic iron. In some embodiments, the method includes introducing a carbon source into the furnace through multiple feed ports and / or multiple injectors. In some embodiments, the carbon source is a solid carbon source and is used to carbonize the metallic iron. In some embodiments, any fluid injected into the slag layer partially flows out without reducing the molten metal oxide. In some embodiments, the fluid flowing out of the molten metal oxide generates a plasma around the electric arc. In some embodiments, ionized fluid around the electric arc is drawn into the molten metal oxide by the momentum of the arc. In some embodiments, the ionized fluid reduces the molten metal oxide near the arc. In some embodiments, the ionized fluid around the electric arc becomes non-ionized and contributes to heat generation in the furnace by generating heat. In some embodiments, the furnace is a DC or AC electric arc furnace. In some embodiments, the method operates in a batch mode, a continuous mode, or a semi-continuous mode.

[0018] It will be understood that any variations, aspects, features, and options described with respect to a furnace may be applied to the systems, methods, and other furnaces as well, and vice versa. It will also be apparent that any one or more of the variations, aspects, features, and options described above may be combined.

[0019] Further advantages will become readily apparent to those skilled in the art from the following detailed description. The aspects and descriptions herein are to be considered illustrative in nature and not restrictive.

[0020] All publications, including patent documents, scientific articles, and databases, referred to in this application are incorporated by reference in their entirety for all purposes to the same extent as if each publication was individually incorporated by reference. To the extent that a definition set forth herein contradicts or is inconsistent with a definition set forth in a patent, application, published application, or other publication incorporated herein by reference, the definition set forth herein shall take precedence over the definition incorporated herein by reference. [Brief explanation of the drawings]

[0021] The invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0022] [Figure 1] FIG. 1 illustrates an exemplary steelmaking process according to some embodiments herein.

[0023] [Figure 2] FIG. 2 illustrates another exemplary steelmaking process according to some embodiments herein.

[0024] [Figure 3] FIG. 3 shows an example of a half cross section of a furnace according to some embodiments herein.

[0025] [Figure 4] FIG. 4 illustrates fluid flow in an example half cross section of a furnace according to some embodiments herein.

[0026] [Figure 5] FIG. 5 illustrates radial fluid injection from a top view of a furnace according to some embodiments herein.

[0027] [Figure 6] FIG. 6 illustrates angled fluid injection from a top view of a furnace according to some embodiments herein.

[0028] [Figure 7A]FIG. 7A shows a top view of an exemplary zone of a metal oxide feedstock according to some embodiments herein.

[0029] [Figure 7B] FIG. 7B shows a cross section of an exemplary zone of metal oxide source, metal layer, slag layer, and feed accumulation according to some embodiments herein.

[0030] [Figure 8] FIG. 8A shows a diagram of the components of a slug layer according to some embodiments herein.

[0031] [Figure 8] FIG. 8B shows a close-up view of a component of the slug layer according to some embodiments herein.

[0032] [Figure 9A] FIG. 9A illustrates a portion of a cross section of an exemplary shell of a furnace according to some embodiments herein.

[0033] [Figure 9B] FIG. 9B shows a larger portion of a cross section of an exemplary furnace with a shell according to some embodiments herein.

[0034] [Figure 10A] FIG. 10A illustrates a top view of an exemplary furnace design according to certain embodiments herein.

[0035] [Figure 10B] FIG. 10B illustrates a cross section of an exemplary furnace design according to some embodiments herein.

[0036] [Figure 11] FIG. 11 shows an example layout of electrodes as viewed from the roof of the furnace according to some embodiments herein.

[0037] [Figure 12A]FIG. 12A shows an exemplary hydrogen utilization flow chart according to some embodiments herein.

[0038] [Figure 12B] FIG. 12B shows an exemplary hydrogen utilization chart versus weight percent of FeO in the slag, according to some embodiments herein.

[0039] [Figure 12C] FIG. 12C shows an exemplary hydrogen flow rate chart versus weight percent of FeO in the slag, according to certain embodiments herein.

[0040] [Figure 12D] FIG. 12D shows another example hydrogen flow rate chart, according to some embodiments herein.

[0041] [Figure 13A] FIG. 13A illustrates another exemplary steelmaking process according to some embodiments herein.

[0042] [Figure 13B] FIG. 13B illustrates another exemplary steelmaking process according to certain embodiments herein.

[0043] [Figure 13C] FIG. 13C illustrates another exemplary steelmaking process according to some embodiments herein.

[0044] In the figures, like reference numbers refer to like elements unless otherwise stated herein. DETAILED DESCRIPTION OF THE INVENTION

[0045] Implementations and embodiments of various aspects and variations of the furnaces, systems, and methods described herein are described in detail below. While several exemplary variations of the furnaces, systems, and methods are described herein, other variations of the furnaces, systems, and methods may include aspects of the furnaces, systems, and methods described herein that combine aspects in any suitable manner having a combination of all or a portion of the described aspects. For example, variations of the systems and methods may be applied to convert a feed or slag containing molten metal oxides into refined metals.

[0046] The BF-BOF process for producing steel is an energy-intensive four-step process. This process includes converting coal into coke in a coke plant, sintering or pelletizing fines or lump iron ore in a separate process, reducing the iron ore to carbonized metallic iron in a blast furnace, and removing excess carbon and / or adding scrap metal in a basic oxygen furnace. The blast furnace is the most energy-intensive step because it involves using coke to heat iron oxide above the melting point of iron and then using the coke as a reducing agent to convert the iron oxide to metallic iron. Alternative processes, such as direct reduction of iron (DRI) in an electric arc furnace (EAF), can significantly reduce carbon emissions compared to the blast furnace by using natural gas and / or hydrogen as reducing gases. However, DRI-EAF is a three- to four-step process, first pelletizing high-grade iron ore, reducing the iron ore in the DRI process, and then melting the reduced iron in the EAF or melting the reduced iron in a submerged arc furnace and then refining it in the EAF. In the DRI process, when using only hydrogen, additional heat input may be required due to the overall endothermic nature of the molecular hydrogen reaction. Currently, 5% of the hydrogen gas mixture can consist of natural gas or other carbon-containing gases to offset the energy demand of the endothermic reactions in the DRI process. Furthermore, because EAF has historically relied on the carbon contained in iron (called pig iron), DRI-EAF may still require carbon input to maintain the downstream EAF temperature through the exothermic reaction of carbon and oxygen. Hydrogen plasma smelting reduction (HPSR) and / or molecular hydrogen reduction reactions can improve both processes by utilizing the ionized state of hydrogen to reduce iron ore and contribute to heat generation. Hydrogen ions have a high reduction potential and can reduce iron ore to molten iron and steel in a single step. HPSR can be an entirely exothermic reaction, and the heat energy generated by the ionization of the gases can be harnessed and recycled. Therefore, HPSR and / or molecular hydrogen reduction reactions can reduce capital costs, operating costs, and carbon emissions compared to the BF-BOF and DRI-EAF processes.When combined with the method for reducing iron oxide in the slag layer with molecular hydrogen disclosed herein, the HPSR and / or molecular hydrogen reduction process becomes scalable and economically viable.

[0047] Disclosed herein are systems, methods, and furnaces for molten metal production. The furnaces described herein are capable of performing HPSR and / or molecular hydrogen reduction reactions. Through various hydrogen injection modes, the furnaces described herein can improve reduction kinetics and overall hydrogen utilization in HPSR and / or molecular hydrogen reduction compared to state-of-the-art HPSR systems and hydrogen DRI processes. The hydrogen injection modes described herein can improve the surface area for performing HPSR and / or molecular hydrogen reduction reactions. The systems, methods, and furnaces described herein can recycle thermal energy and off-gas to improve energy efficiency and reduce operating costs. Furthermore, the systems, methods, and furnace components described herein are compatible with commercial steelmaking furnaces, accelerating technology adoption.

[0048] Disclosed herein is a furnace that can be used to produce molten metal. The furnace can have walls (e.g., sidewalls) and / or shell(s), and the shell can have a top and a bottom. The top can include a roof, and the bottom can include a hearth, and the wall, shell, or a combination thereof can connect the roof and hearth. The shell or wall can include multiple injectors. In some embodiments, the injector can be configured to inject a fluid into the furnace. In some embodiments, the fluid can be molecular hydrogen. In some embodiments, the furnace can be used to perform HPSR and / or molecular hydrogen reduction reactions, in which case the hydrogen (e.g., molecular hydrogen) can be heated. The furnace can provide energy to the hydrogen, ionizing it to function as a reducing agent. In some embodiments, the injector can inject the hydrogen without preheating, in which case electrodes in the furnace can heat the hydrogen and melt or maintain the feed in a molten state as needed. In some embodiments, the injectors can preheat the hydrogen, allowing the furnace to instead heat primarily iron ore or metal oxides, thereby reducing the heat load on the furnace and improving energy efficiency.

[0049] In some embodiments, at least one electrode may be attached to the roof of the furnace. The roof may have multiple feed ports through which iron ore or metal oxides can be fed into the furnace. The electrode may be used to heat a reducing gas or to melt the iron ore or metal oxides fed into the furnace. In some embodiments, a counter electrode may be attached to the hearth of the furnace. In some embodiments, the electrode is used to generate an arc between the electrode and a powered electrode or a counter electrode. In some embodiments, the temperature surrounding the electric arc may exceed 3,000 degrees Celsius. In some embodiments, the electrode is submerged, in which case ionized hydrogen is not formed. Rather, injected molecular hydrogen can initiate the reduction reaction. In some embodiments, multiple electrodes may be attached to the roof within a certain distance of each other so that the formed arcs converge toward the center of the roof. In some embodiments, the distance between the electrodes is such that the arcs operate independently of each other.

[0050] In some embodiments, the hearth can hold a molten bath. The molten bath can include a slag layer, which may contain molten metal oxides, and a metal layer, which may contain molten metal. In some embodiments, HPSR and / or molecular hydrogen reduction reactions can occur within the slag layer. In some embodiments, the slag layer can be foamy. In some embodiments, the slag is located above the metal layer, and as the metal oxides in the slag are reduced to molten metal, the metal can sink toward the bottom of the hearth. In some embodiments, metal oxides accumulate around the arc, and HPSR and / or molecular hydrogen reduction reactions occur within the slag or the deposited metal oxides above the molten bath.

[0051] In some embodiments, the furnace can be configured to melt metal oxides entering the furnace to form a molten bath. In some embodiments, the furnace can be configured to receive the molten bath (including both the slag layer and the metal layer) and maintain it in a molten state. In some embodiments, the furnace can be configured to melt the metal oxides, maintain the metal and slag layers in a molten phase, provide thermal energy to the furnace, provide an ionized gas to the bath, and / or reduce the metal oxides. FIG. 3 shows an example of a half cross-section of a furnace 300 disclosed herein. In some embodiments, the furnace can be provided in a wide variety of shapes and sizes. For example, the furnace can be spherical, cylindrical, square, rectangular, etc. For example, FIGS. 3-4 show a cylindrical furnace, and FIG. 10 shows a rectangular furnace. In some embodiments, the diameter D of the furnace can be about 1 to 100 meters, about 1 to 50 meters, about 1 to 25 meters, about 5 to 25 meters, about 10 to 20 meters, or about 15 meters.

[0052] In some embodiments, the furnace may include a roof or top 301. The roof may be configured to introduce materials, such as metal oxides, into the furnace for melting. In some embodiments, the metal oxide may be any element used in steel production. In some embodiments, the metal oxide is iron ore. In some embodiments, the iron ore may be in the form of granules, chunks, and / or pellets. In some embodiments, the metal oxide may include iron oxide, hematite, magnetite, an iron oxide-containing waste stream, or a combination thereof. Examples of iron oxide-containing waste streams include waste generated from mineral sand processing and waste generated when converting ilmenite to synthetic rutile by the Becher process. In some embodiments, the metal oxide may be pre-reduced metal oxide. In some embodiments, off-gas from the furnace may consist partially of reducing gas and be used to pre-reduce the metal oxide. The off-gas may be generated by all gases in the furnace, including hydrogen that did not react with the materials in the furnace, water vapor from hydrogen reacting with oxygen in the furnace, and gangue elements (e.g., sulfur and phosphorus) vaporized due to the high temperature in the furnace. In some embodiments, the pre-reduction of the metal oxide may occur in a separate furnace. In some embodiments, the off-gas can be treated to remove water vapor and / or vaporized gangue elements, leaving primarily hydrogen. The hydrogen can be reinjected into the furnace. In some embodiments, the off-gas can be treated to remove vaporized gangue elements and reduce the temperature. This reduced and treated off-gas can be sent to a low-temperature or high-temperature water electrolysis device to regenerate a liquid (e.g., hydrogen gas) from the solid water.

[0053] In some embodiments, the feed port can be configured to introduce a carbon source into the furnace. In some embodiments, the carbon source can be a solid carbon source such as biochar, coal, graphite, methane, natural gas, and / or carbon black. In some embodiments, solids introduced into the furnace through the feed port or injected through an injector (described below) can serve as nucleation points for bubble nucleation. In some embodiments, the carbon source is injected into the metal bath for carbonization of the molten metal. In some embodiments, the carbon source can be a gas and is introduced through a fluid injector. In some embodiments, the gaseous carbon source can be natural gas / methane.

[0054] In some embodiments, the roof may include multiple feed ports 303. The feed ports (bins or hoppers) may be configured to introduce metal oxides into the furnace for subsequent melting. In some embodiments, the multiple feed ports may be arranged in a circular or annular configuration around the furnace roof, as shown in FIGS. 5-6. In some embodiments, the multiple feed ports may be arranged in a circular or annular configuration around the center of the roof. In some embodiments, the multiple feed ports may be arranged around the periphery of the roof, as shown in FIG. 10. In some embodiments, each feed port of the multiple feed ports may be positioned equidistant from one another. In some embodiments, the number of feed ports may be determined depending on the area of influence of the fluid injection, as described below.

[0055] In some embodiments, the multiple feed ports can be configured so that feed ports closer to the center of the roof can introduce more metal oxide into the furnace than feed ports further from the center of the roof. For example, FIGS. 7A and 7B show examples of zoning the feed ports from the perspective of a cross section or half of a cross section of a cylindrical furnace. In some embodiments, the feed ports can be arranged in at least one circular or annular zone around the center of the roof. In some embodiments, a zone closer to the center of the roof can introduce more source material (e.g., metal oxide) than an adjacent zone further from the center of the roof. These feed port zones can be arranged annularly around the center of the roof. For example, FIGS. 7A and 7B show feed port zones Z1, Z2, and Z3. Z1, which is closer to the center of the roof (electrode 310) than Z2 and Z3, can introduce more source material than Z2 and Z3. For example, a supply port Z1 closer to the center of the roof may introduce 60% of the total supply, a supply port Z2 further from the center of the roof than Z1 may introduce 30% of the total supply, and a supply port Z3 further from the center than Z2 may introduce 10% of the total supply. Thus, supply port zones further from the center of the roof may introduce a lower percentage of the total supply than those ports closer to the center of the roof. In some embodiments, the opposite may be true (i.e., supply port zones further from the center of the roof may introduce a higher percentage of the total supply than those ports closer to the center of the roof). Additionally, gas injectors may be positioned through ports in the roof, such as top submerged lances.

[0056] In some embodiments, molten metal can be formed by introducing metal oxides into the furnace through multiple feed ports in the furnace roof. For example, the furnace can be configured to melt metal oxide raw materials to form a molten bath. In some embodiments, the molten bath can include at least a slag layer 307 and a metal layer 308. In some embodiments, the slag layer can include slag. In some embodiments, the slag layer can include molten metal oxides. In some embodiments, the slag layer can be a by-product of melting raw materials (e.g., iron ore). In some embodiments, the slag layer can include ferrous materials, iron alloys, and / or non-ferrous / base metals (e.g., copper, nickel, zinc, phosphorus, etc.). In some embodiments, the slag layer can include a fluid capable of reducing the molten metal oxides. In some embodiments, the metal layer can include molten metal. In some embodiments, the slag layer can be a by-product produced during the separation of molten metal from impurities in a molten metal production process. In some embodiments, the molten metal can include metallic iron that can be used for steel. In some embodiments, only the slag layer is present without metal being separated from the slag layer.

[0057] In some embodiments, components within the slag layer (e.g., molten metal oxides) can be reduced to form molten metal within the metal layer. The metal layer can be denser than the slag layer, causing the metal layer to sink to the bottom of the furnace with the slag layer on top. For example, FIG. 8B shows how fluid or fluid bubbles 313 (e.g., hydrogen gas) within the slag layer 307 reduce metal oxides (e.g., iron oxide) 320 within the slag layer to form metal 321 (e.g., metallic iron), which is denser than the metal oxide and sinks or precipitates toward the bottom of the furnace. Depending on the density and viscosity of the slag layer, agitation within the slag layer, and bath mixing, some of the metal may remain as droplets within the slag layer. Above the slag layer, unreacted fluids (see below), product gases (e.g., steam), and / or evaporated gangue elements (e.g., sulfur and phosphorus) from the reduction process may be present.

[0058] In some embodiments, the furnace can include a shell, wall, or multiple walls (e.g., sidewalls) 302. The shell functions as a sidewall or wall of the furnace. In some embodiments, the shell can include multiple walls. In some embodiments, the shell can be cylindrical, square, rectangular, spherical, etc. In some embodiments, the shell can include a top and a bottom. In some embodiments, a roof can be connected to the top of the shell and surround the top of the furnace / shell. In some embodiments, the roof and shell can be integrally connected / coupled to form a single unit. In some embodiments, the furnace can include a hearth 309 at the bottom of the furnace. In some embodiments, the hearth can be connected to the bottom of the shell and surround the bottom of the furnace / shell. In some embodiments, the hearth and shell can be integrally connected / coupled to form a single unit. In some embodiments, the roof, shell, and hearth can be integrally connected / coupled to form a single unit. In some embodiments, the furnace wall or shell can include a feed port.

[0059] In some embodiments, the shell can include multiple injectors 304 configured to inject fluid 305 into the furnace. The fluid injected into the furnace can reduce the raw materials (e.g., metal oxides) and / or materials in the slag layer (e.g., molten metal oxides). The injectors can inject the fluid into the furnace to ensure sufficient residence time for the metal oxides in the slag layer to be reduced to metal. In some embodiments, the fluid can reduce the molten metal oxides in the slag layer to molten metal, which can precipitate in a metal layer below the slag layer. In some embodiments, the fluid can reduce the metal oxides to metal (e.g., metallic iron) before melting. In some embodiments, the fluid can also reduce ilmenite, copper oxide, and / or other metal oxides or ores in the furnace or slag layer. In some embodiments, the fluid can be a reducing gas. In some embodiments, the reducing gas is hydrogen gas (e.g., molecular hydrogen), atomic hydrogen, ionized hydrogen, methane, natural gas, ammonia, and / or other hydrogen-containing fluids or gases.

[0060] In some embodiments, at least one of the multiple injectors is configured to inject a fluid into the furnace such that the fluid can agitate the molten bath, slag layer, and / or metal layer within the furnace. In some embodiments, the fluid is introduced into the furnace to agitate the molten bath, create a homogeneous slag composition, and / or promote separation of the molten metal contained in the slag so that the molten metal can collect / precipitate in the metal layer below the slag layer. In some embodiments, at least one of the multiple injectors can be configured to inject a fluid into the furnace such that the fluid induces mixing of the slag layer and / or metal layer of the molten bath. Such mixing and / or agitation 312 can increase the rate of gas-solid and / or gas-liquid reduction reactions within the furnace. In some embodiments, the multiple injectors can be configured to inject a fluid such that the fluid can penetrate the molten bath (e.g., the slag and / or metal layer).

[0061] In some embodiments, at least one of the plurality of injectors is configured to inject fluid radially inward into the furnace, as shown in FIG. 5. In some embodiments, at least one of the plurality of injectors is configured to inject fluid toward a hearth of the furnace, as shown in FIGS. 3-4. In some embodiments, at least one of the plurality of injectors is configured to inject fluid toward a molten bath in the furnace. In some embodiments, at least one of the plurality of injectors is configured to inject fluid toward a working region of the furnace. In some embodiments, the working region may be where the molten bath and / or slag layer (e.g., molten metal oxide) is located in the furnace. In some embodiments, at least one of the plurality of injectors can be configured to inject fluid into a molten bath of the furnace. In some embodiments, at least one of the plurality of injectors can be configured to inject fluid into a slag layer and / or metal layer of a molten bath in the furnace. In some embodiments, the injector can be submerged in the molten bath. In some embodiments, the injector can be positioned above the molten bath.

[0062] In some embodiments, injection of a fluid into the molten bath (e.g., the slag layer and / or the metal layer) can result in fluid flow due to buoyancy effects (the density of the fluid can be less than the density of the molten bath, the density of the slag, or the density of the metal) and momentum transfer from the injected fluid to the molten bath. In some embodiments, momentum transfer from the injected fluid to the molten bath can also occur because the injected fluid can break down into bubbles 313 within the molten bath. Therefore, buoyancy and / or mixing from the injected fluid can increase the reduction reaction rate within the furnace. In some embodiments, the fluid injected into the furnace can be sheared within the molten bath (e.g., the slag layer and / or the metal layer) to generate individual gas volumes that can become bubbles 313. In some embodiments, at least some of the bubbles 313 can be spherical. In some embodiments, at least some of the bubbles 313 can be non-spherical. The amount, volume, and shape of the individual gas volumes can vary based on the angle and direction of shear created by the fluid injector.

[0063] In some embodiments, at least one of the multiple injectors can be configured to inject fluid toward and / or into a first region of the molten bath (e.g., a slag layer). In some embodiments, at least one of the multiple injectors is configured to inject fluid toward and / or into a second region of the molten bath that is different from the first region of the molten bath, allowing the fluid to reach / interact with different regions of the molten bath. In some embodiments, each injector of the multiple injectors is configured to inject fluid toward and / or into a different region of the molten bath.

[0064] In some embodiments, at least one of the multiple injectors can be configured to inject fluid in a direction toward an adjacent injector. In some embodiments, the multiple injectors can be configured to inject fluid such that the slag and / or metal layers of the molten bath swirl within the furnace, increasing mixing and / or agitation of the molten bath and the fluid (thus increasing the reduction reaction rate). In some embodiments, the furnace shell can have an internal axis A that runs longitudinally through the center of the shell (and furnace), as shown in FIG. 7B. In some embodiments, at least some of the multiple injectors can be configured to inject fluid at an angle less than 90 degrees relative to a line perpendicular to the internal axis and tangent to each injector in a cross-section of the shell. For example, FIG. 6 shows a cross-section of the shell perpendicular to the internal axis. In FIG. 6, the injectors are configured to inject fluid at an angle 317 less than 90 degrees (e.g., 10 to 45 degrees, 10 to 30 degrees, 20 to 30 degrees, or 20 to 25 degrees) relative to a line 316 tangent to each injector 304 in a cross-section. Tilting such an injector can create a swirling effect 318 of the molten bath (e.g., slag layer and / or metal layer). In some embodiments, multiple injectors can be evenly spaced around the circumference of the shell. In some embodiments, multiple injectors can be evenly spaced around the circumference of the shell.

[0065] In some embodiments, at least one of the multiple injectors can be submerged in the molten bath. In some embodiments, at least one of the multiple injectors can be submerged in the slag layer and / or the metal layer of the molten bath. In some embodiments, at least one of the multiple injectors can be submerged in the molten bath between the slag layer and the metal layer. In some embodiments, the submerged injector can contact both the slag layer and the metal layer of the molten bath. In some embodiments, the multiple injectors can include injectors that are submerged in the molten bath and injectors that are not submerged (e.g., above the molten bath).

[0066] In some embodiments, the roof can also include at least one injector configured to inject fluid into the furnace. In some embodiments, the roof can include multiple injectors configured to inject fluid vertically into the furnace. In some embodiments, the multiple injectors in the roof can be configured to inject fluid at a 90 degree angle relative to the roof so as to be perpendicular to the molten bath (e.g., the slag layer of the molten bath).

[0067] In some embodiments, the injectors disclosed herein can include a lance, a supersonic jet, a coherent jet, a plasma torch or jet, an injector configured to inject both gas and solid, or a combination thereof. In some embodiments, the plasma torch can be a non-thermal plasma torch. In some embodiments, the coherent jet can include a supersonic coherent jet, a subsonic coherent jet, and / or a coherent jet with a shrouded flame. In some embodiments, the fluid can be preheated before being injected into the furnace, so that thermal energy within the furnace is not wasted on heating the fluid. In some embodiments, the plasma torch can electrically heat the fluid before being injected into the furnace, so that the fluid contributes to the thermal energy provided to the furnace and / or molten bath (if hotter than the molten bath) or, if at the same temperature as the bath, so that furnace energy is not wasted on heating the fluid.

[0068] In some embodiments, the shell can include at least one heat exchanger 322. In some embodiments, at least one heat exchanger can be used to prevent the shell itself from melting due to the heat utilized in the furnace. In some embodiments, the shell can include multiple heat exchangers for cooling the shell. In some embodiments, the at least one heat exchanger can be a heat exchanger that utilizes water cooling through the interior of the shell. In some embodiments, the shell can be formed from multiple shell segments, as shown in FIG. 9B. In some embodiments, the interior of the shell can include multiple notches, spaces, or openings 325 through which slag can solidify 323, thereby forming a protective layer on the interior of the shell. In some embodiments, the shell can be made of copper. In some embodiments, the shell can include at least one copper cooler. In some embodiments, the roof can also be made of copper and / or include at least one copper cooler. The copper cooler can include at least one heat exchanger (e.g., water-cooled) within the cooler wall. In some embodiments, the interior of the furnace (e.g., shell, roof, and / or hearth) can be lined with a castable refractory lining 324. Arc radiation and radiation from the molten pool may require resistant materials to line the furnace walls. The purpose of the refractory lining may be to enhance the integrity of the furnace by protecting the walls from molten metal and slag splashes, the high heat inside the furnace, and / or radiation. Additionally, the lining reduces heat loss from the furnace to the surrounding environment. In some embodiments, any state-of-the-art technology for enhancing furnace integrity may be applied.

[0069] In some embodiments, multiple feed ports and / or multiple injectors can be configured to introduce a carbon source into the furnace. In some embodiments, the carbon source is a solid carbon source such as waste plastic, coal, coke, or biochar. In some embodiments, carbon can be injected into the furnace and molten bath so that a desired amount of carbon is present in the molten bath to form a desired product (e.g., 2% carbon in iron for steel production). In some embodiments, metal oxide reduction can occur without added carbon. In some embodiments, solids injected into the furnace via injectors (described below) can serve as nucleation points for bubble nucleation. In some embodiments, solids can be injected simultaneously and / or in combination with fluids in the same or different injectors. The solids can serve as nucleation points for the injected fluid and increase the surface area for reaction between the fluid and the feedstock material (e.g., metal oxide).

[0070] In some embodiments, the furnace may include at least one heating source. In some embodiments, the roof may include at least one electrode 310 (e.g., a cathode) extending from the roof toward the hearth of the furnace. In some embodiments, the hearth may include at least one electrode 326 (e.g., an anode) opposite the at least one electrode. In some embodiments, the at least one counter electrode may be embedded within the hearth of the furnace. The furnace may be configured to generate an electric arc 311 between the distal end of the at least one electrode and at least one counter electrode. In some embodiments, under AC or DC electrical operation, at least one electrode is always a cathode and at least one counter electrode is always an anode. This electric arc may be configured to melt the source material (e.g., metal oxide) to form a molten bath. In some embodiments, the at least one electrode may be positioned at the center of the furnace. In other words, the at least one electrode may be positioned on the inner axis A of the furnace.

[0071] In some embodiments, an electric arc can exist between the distal end of at least one electrode and the molten bath of the furnace. In some embodiments, the distal end of at least one electrode can be positioned above the molten bath or a slag layer of the molten bath. In some embodiments, the distal end of at least one electrode can be immersed in the molten bath (e.g., a slag layer and / or a metal layer). In some embodiments, the electric arc can be a transferred electric arc or a non-transferred electric arc. In embodiments where a transferred arc is used, the molten bath can be part of the electric circuit. An electric arc can be formed between the electrode and the molten bath, but the electrode and the molten bath may not be in direct physical contact with each other. Ionized gas can be generated within and around the electric arc and can come into contact with the molten bath. In embodiments where a non-transferred electric arc is used, the electric arc may not interact with the molten bath. Alternatively, for example, a plasma torch can be used to generate an electric arc between the electrode and the nozzle of the plasma torch. Ionized gas can be generated within the plasma torch, and hot gas is ejected from the torch at a high temperature and high velocity. The transferred arc configuration can provide a 20% improvement in electrothermal efficiency over non-transferred arc technology.

[0072] In some embodiments, the electric arc can contribute to a flow pattern within the molten bath (e.g., the slag layer and / or the metal layer). In some embodiments, the momentum 314 of the electric arc can push a portion of the molten bath (e.g., a portion of the slag layer and / or the metal layer) away from the electric arc, forming a concave depression 327 in the molten layer (e.g., the slag layer and / or the metal layer), as shown in FIGS. 7B and 10B. In some embodiments, fluids and materials (e.g., metal oxides) surrounding the electric arc can be drawn toward the electric arc. In some embodiments, the flow pattern created by the electric arc can counter the buoyancy effect of fluid injected into the molten bath. In this way, both the electric arc and the fluid injection can contribute to stirring / mixing the molten bath and enhance the reduction reaction rate of materials in the molten bath. In some embodiments, flow pattern 315 can exist within the metal layer due to shear forces between the metal layer and the slag layer.

[0073] In some embodiments, at least one electrode may be hollow. As such, at least one electrode may include a port through a central axis of the at least one electrode. In some embodiments, the port may be used to inject fluids and / or supply materials. In some embodiments, at least one electrode may be solid (i.e., not hollow). In such embodiments, fluids may be injected only through multiple injectors in the shell and / or roof, but not through the at least one electrode.

[0074] In some embodiments, at least a portion of a fluid injected into the furnace can pass through an electric arc to form a plasma. In some embodiments, a fluid can be injected into the molten bath, and a portion of the fluid can exit the molten bath without reducing the metal oxides in the slag layer. In some embodiments, the fluid exiting the molten bath can generate a plasma around the electric arc. In some embodiments, a plasma can form around the electric arc. In some embodiments, the plasma can surround the electric arc. The fluid passing through the electric arc can become an ionized fluid. For example, hydrogen gas passing through the electric arc can become ionized hydrogen. In some embodiments, the ionized fluid and / or plasma can exist around the electric arc and / or be drawn into the molten bath. In some embodiments, the plasma can melt the source material (e.g., metal oxide) and / or provide thermal energy to the furnace. In some embodiments, the plasma can also reduce the source material (e.g., metal oxide) or the molten source material (e.g., molten metal oxide). In some embodiments, the ionized fluid around the electric arc can be drawn into the molten bath (e.g., slag layer and / or metal layer) by the momentum of the arc. In some embodiments, the ionized fluid can reduce metal oxides in the slag layer near the electric arc. In some embodiments, the ionized fluid can become non-ionized and contribute to heat generation in the furnace by generating heat. For example, ionized hydrogen around the electric arc can recombine into atomic or molecular hydrogen, generating heat and contributing to heat generation in the furnace.

[0075] In some embodiments, the furnace can be an AC or DC electric arc furnace. In some embodiments, the furnace is a modified AC or DC electric arc furnace. In some embodiments, the furnace components are compatible with AC or DC electric arc furnaces, and AC or DC electric arc furnaces can be retrofitted with any of the components described herein.

[0076] In some embodiments, at least one of the multiple injectors can be configured to inject fluid toward and / or into the electric arc. In some embodiments, at least one of the multiple injectors in the roof can be configured to allow the multiple injectors to approach the center of the roof and / or at least one electrode. In some embodiments, the spacing E between the electrodes ( FIG. 11 ) can be about 1 to 20 meters, about 1 to 15 meters, about 1 to 10 meters, or about 5 to 8 meters.

[0077] In some embodiments, as shown in Figures 10A, 10B, and 11, the roof can include multiple electrodes (e.g., cathodes) extending from the roof toward the hearth of the furnace. The configuration of the electrodes can depend on the shape of the furnace. For example, Figures 10A and 10B show electrodes spaced apart along a rectangular furnace, while Figure 11 shows electrodes spaced apart within a cylindrical furnace. In some embodiments, the furnace can be configured to generate an electric arc between the distal end of each of the multiple electrodes and at least one counter electrode (e.g., an anode). In some embodiments, the distance between the multiple electrodes is such that no electric arc interference can occur between the electric arc of each electrode and the at least one counter electrode. In some embodiments, the at least one electrode and / or the at least one counter electrode can be made of carbon, graphite, titanium, tungsten, tantalum, zirconium, copper, or a combination thereof.

[0078] FIG. 1 illustrates an exemplary steelmaking process according to some embodiments of the present disclosure. As shown in FIG. 1, iron ore or metal oxides can be introduced into a dryer 101 to remove excess moisture. The iron ore or metal oxides can be directly introduced into the dryer or can be mixed with iron ore dust that is first collected in a cyclone system 107 and processed in a scrubber 108. The scrubber 108 can liberate the ore and hydrogen from water vapor, harmful minerals, or gases. Harmful materials can include gangue elements and oxides. Gangue can include SiO2, CaO, MgO, and Al2O3. Gangue and other impurities can be discharged through an impurity bleed 114. After being discharged from the scrubber, the refined material 112 is separated into solid and liquid components, and the solid components of the refined material, such as iron ore dust, can enter the dryer 101. The dryer 101 can optionally use an additional heat exchanger or secondary process 113 to mix high-grade iron ore with the solid components of the refined material before the solids enter the dryer. The processed and dried iron ore can be introduced into the pre-reduction chamber 102 to produce pre-reduced iron. For example, the pre-reduction chamber 102 can be a fluidized bed, reduction shaft, cyclone converter, entrained-flow bed reactor, countercurrent shaft furnace, or any gas-solid reactor. In some embodiments, the pre-reduction chamber 102 can include other equipment from a conventional blast furnace or equipment used in direct reduction of iron (DRI) processes, such as a bubbling fluidized bed reactor for reducing fine iron ore or a shaft furnace for pelletized iron ore. In other embodiments, the pre-reduction device can be included within the main furnace. In this embodiment, the furnace can have two compartments: an upper compartment where the off-gas flows upward, away from the arc, and through a shaft at the top of the furnace, through which the iron ore falls to the lower compartment where it is smelted and the final reduction stage of FeO to metallic Fe takes place. In some embodiments, the two compartments are in direct communication. In other embodiments, a heat exchanger is present between the two compartments to reduce the temperature of the off-gas before pre-reducing the metal oxides.

[0079] Hydrogen functions as a reducing gas, and a hydrogen supply 111 can supply hydrogen gas / molecular hydrogen to the pre-reduction chamber 102 and the main furnace 103. The main furnace 103 can be any of the furnace embodiments described herein. The hydrogen gas / molecular hydrogen can be compressed by a compressor 109. The compressed hydrogen can enter the pre-reduction chamber 102 and the main furnace 103 along with the dried iron ore or metal oxide. In the pre-reduction chamber, the iron ore or metal oxide can be pre-reduced by hydrogen. In some embodiments, the pre-reduction can occur through a blast furnace process or a DRI process. In the main furnace 103, pre-reduced iron ore or metal oxide, or iron ore or metal oxide from the dryer 101, can be reduced via a hydrogen plasma smelting reaction (HPSR) and / or a molecular hydrogen reduction reaction. HPSR can be an entirely exothermic reaction due to the exothermic recombination reaction between ionized hydrogen and can reduce metal oxides with a lower heat demand than reactions relying solely on molecular hydrogen.

[0080] The reduction product from the main furnace 103 can be liquid iron / metal, matte, slag, or steel. The reduced product can be transferred to the ladle 105, which is a furnace capable of smelting liquid iron / metal or steel. The slag produced from HPSR and / or molecular hydrogen reduction in the main furnace 103 can enter the slag granulation system 104. The slag granulation system 104 atomizes the slag to release thermal energy that can be recycled back to the dryer 101, thereby reducing energy consumption.

[0081] To further improve energy efficiency, residual materials from the pre-reduction, HPSR, and / or molecular hydrogen reduction can be recycled. The residual materials may include solids such as unreacted iron ore / metal oxides, as well as off-gas, gangue elements, or water vapor. The off-gas can be discharged from the main furnace 103 or the pre-reduction chamber 102, where it can pass through a recuperator 106. The recuperator 106 can perform counterflow heat exchange and recycle thermal energy from the off-gas. A cyclone 107 can be used to separate residual iron ore / metal oxide dust from the off-gas after it is discharged from the recuperator 106. The residual iron ore / metal oxide can then re-enter the pre-reduction chamber 102.

[0082] The off-gas exits the cyclone 107 and enters the scrubber 108, where hydrogen and other gases can be separated from the gangue elements. After exiting the scrubber, the gas re-enters the compressor and is used again in another reduction reaction. There may be a fan 115 to facilitate the flow of purified gas and hydrogen to the compressor. Additionally, there may be a gas bleed 110 to separate non-condensable off-gas from the hydrogen so that it does not enter the main smelting reduction furnace 103. These non-condensable gases may include nitrogen, carbon dioxide, carbon monoxide, or a combination thereof.

[0083] FIG. 2 illustrates another exemplary steelmaking process according to some embodiments of the present disclosure. As shown in FIG. 2, iron ore or metal oxides may first be introduced into a dryer 201 to remove water. The treated and dried iron ore may then be introduced into a pre-reduction chamber 202 to produce pre-reduced iron. For example, the pre-reduction chamber 202 may be a fluidized bed with bubbling or circulation, a reduction shaft, a cyclone converter, an entrained bed reactor, or a countercurrent shaft furnace. In some embodiments, the pre-reduction chamber 202 may include other equipment from a blast furnace or equipment used in a direct iron reduction (DRI) process.

[0084] Hydrogen can be introduced into the pre-reduction chamber 202 from a hydrogen supply 211. The hydrogen supply 211 can also introduce hydrogen that is injected into the main furnace 203. The main furnace 203 can include any of the furnace embodiments described herein. In some embodiments, the hydrogen introduced by the hydrogen supply can be supplied to the pre-reduction chamber 202 or the main furnace 203 without being compressed by the compressor 209.

[0085] In the main furnace 203, pre-reduced iron ore or metal oxides can be reduced by injected hydrogen via HPSR and / or molecular hydrogen reduction. HPSR is an exothermic reaction and can occur without the need for additional heat. The reduction product from the main furnace 203 can be liquid iron / metal or steel. The reduced product can be transferred to the ladle 205. The ladle 205 is a furnace that can smelt the liquid iron / metal or steel. Slag 204 can also be produced from the main furnace 203, and the heat energy from the slag 204 may or may not be recycled.

[0086] To further improve energy efficiency, residual materials from the pre-reduction, HPSR, and / or molecular hydrogen reduction can be recycled. The residual materials may include solids such as unreacted iron ore / metal oxides, and off-gases containing unreacted hydrogen, gangue elements, or water vapor. The off-gases can be discharged from the main furnace 203, where they can pass through a recuperator 206, where countercurrent heat exchange can occur and thermal energy from the off-gases can be recycled. A fan 212 can facilitate circulation of the off-gases through the recuperator 206. Hydrogen may be pressurized and heated before being discharged from the recuperator 206 and recycled to the pre-reduction chamber 202.

[0087] The off-gas and residual solids may be discharged from the pre-reduction chamber 202 and enter a cyclone 207. The cyclone 207 can be used to separate the residual iron ore / metal oxide from the off-gas and recycle the residual iron ore / metal oxide and off-gas, which may then re-enter the pre-reduction chamber 202. The off-gas may be discharged from the cyclone 207 and enter a scrubber 208. The scrubber 208 can separate hydrogen from non-condensable gases, which may include nitrogen and carbon dioxide. The non-condensable gases are discharged through a gas bleed 210, and the recycled hydrogen may enter a compressor 209 before being injected into the main furnace 203.

[0088] In another embodiment, the high-temperature steam exiting the reactor or pre-reduction chamber can be sent to a steam electrolyzer (also known as a solid oxide electrolyzer (SOEC)) for further hydrogen production. Prior to the SOEC, gangue components may be removed from the off-gas to prevent poisoning of the SOEC. Hydrogen produced via the SOEC is returned to the reactor for metal oxide reduction.

[0089] FIG. 12A shows an example hydrogen utilization flow chart according to some embodiments herein, and FIGS. 12B-12D show example hydrogen utilization and flow rate charts associated with the hydrogen utilization flow chart. More specifically, FIG. 12A shows an example of iron production characteristics for a 200,000 ton / year single-electrode furnace with an unoptimized flow sheet and no gas preheater. An 80 MW electric arc furnace, hydrogen, and steam from the pre-reduction furnace can be sent to the main electric arc furnace (EAF). Iron ore can be partially metallized to iron in pre-reduction before the furnace. H2 gas can be heated in the EAF. Pre-reduction gas can enter at approximately 800 to 1000°C (to 900°C) and exit at approximately 200 to 400°C (to 300°C). Pre-reduction stage solids (e.g., iron ore) can be input at approximately 20 to 30°C (to 25°C) and discharged at approximately 600 to 800°C (to 700°C). The EAF can heat solids from 700 to about 1600-1700°C (to 1625°C).

[0090] In some embodiments, the methods described herein can be applied to batch, continuous, or semi-continuous production of metals from metal oxides. In some embodiments, a high weight percent of metal oxide in the slag is maintained to enhance hydrogen utilization in the process, according to the exemplary chart in FIG. 12B. The metal layer below the slag can be harvested continuously or batchwise. Once a critical amount of high-metal-oxide-containing slag is produced, the amount of reducing agent (e.g., hydrogen) injected into the slag can be increased to convert the remaining oxides in the slag to metal. The slag can then be removed, and the cycle can begin again with a high weight percent of metal oxide maintained in the slag for the majority of the operation.

[0091] In some embodiments, at least two of the furnaces described herein are in communication. In the first furnace, a high metal oxide content slag can be maintained above the metal layer, maximizing hydrogen utilization during operation. The slag from the first furnace can then be transferred to a second furnace, where a reducing agent can be injected into the slag to recover metals from the metal oxides in the slag (e.g., Fe from FeO). Both furnaces may or may not use an electric arc to generate ionized hydrogen or provide heat to the furnace.

[0092] FIG. 13A illustrates an exemplary steelmaking process according to some embodiments of the present disclosure. As shown in FIG. 13A, iron ore or metal oxides in the form of granules, chunks, pellets, etc. can be introduced into a dryer 1301 to remove excess moisture. The dryer 1301 can be heated, for example, by a hydrogen-fuel burner. In the case of fine iron ore or metal oxides, the dryer 1301 can be a fluidized bed. In some embodiments, the dried iron ore or metal oxides can be introduced directly into a main furnace 1303. Within the main furnace 1303, the iron ore or metal oxides can be reduced to metals. Unreduced metals and gangue elements, or oxides from the ore, can be removed from the furnace as slag. The oxides introduced into the furnace 1303 can be reduced with hydrogen or a hydrogen mixture (e.g., molecular hydrogen, hydrogen plasma, a hydrogen-argon mixture, or a hydrogen-nitrogen mixture), which can be preheated by a preheater 1304. Hydrogen may be compressed above ambient pressure by compressor 1305 before being introduced into furnace 1303 or preheater 1304. Compressed or uncompressed hydrogen may be introduced into furnace 1303 through ports, lances, or gas injectors around the furnace, which may introduce hydrogen directly into or above the slag bath. Hydrogen may additionally or alternatively be introduced through hollow electrodes within furnace 1303. Hydrogen introduced into the furnace may come into contact with an electric arc within the furnace, generating a hydrogen plasma (i.e., ionized hydrogen). The ionized hydrogen may react with metal oxides to reduce them.

[0093] Heat from the main furnace 1303 can be recovered to maximize thermodynamic efficiency and minimize operating costs. Off-gas from the furnace 1303 can be introduced into a recuperator 1306 or other type of heat exchanger or heat recovery boiler. The heat recovered from the recuperator 1306 can be used to preheat hydrogen or other reducing gas in a preheater 1304. The cool off-gas from the recuperator 1306 can be introduced, for example, into an electrostatic precipitator 1307. The electrostatic precipitator 1307 separates residual metal oxide dust from the off-gas, which can then be reintroduced into the dryer 1301 or furnace 1303. The electrostatic precipitator 1307 can be heated using the off-gas from the dryer 1301. The off-gas can then be introduced into a gas scrubber and / or condenser 1308 to separate residual hydrogen from the water vapor. SO present in the off-gas can be removed by condensing the SO present in the off-gas. x or NO x Other gases such as may additionally or alternatively be separated from the off-gas via a scrubber 1308.

[0094] In another embodiment, scrap metal, in addition to iron ore, can be added to the main furnace 1303 to produce steel. In yet another embodiment, iron removed from the main furnace 1303 is introduced into a ladle furnace where it is smelted into steel. In yet another embodiment, carbon is introduced into the main furnace 1304 depending on the desired steel alloy composition. The introduced carbon dissolves in the iron bath and steel is removed from the main furnace 1304.

[0095] FIG. 13B illustrates yet another exemplary steelmaking process according to some embodiments. As shown in FIG. 13B, iron ore or metal oxide may first be introduced into a pelletizer 1311 to combine the ore or oxide into pellets. The pelletized iron ore or metal oxide may then be introduced into a dryer 1312 to remove moisture, including water of crystallization. The pelletized and dried iron ore may then be introduced into a pre-reduction chamber 1313 to produce pre-reduced iron oxide. The pre-reduction chamber 1313 may be a shaft furnace, rotary kiln, or alternative furnace embodiment. In some embodiments, the pre-reduction chamber 1313 may include other equipment from a blast furnace or equipment used in a direct iron reduction (DRI) process.

[0096] Hydrogen can be introduced into the pre-reduction chamber 1313 from a hydrogen supply. The hydrogen supply can additionally or alternatively introduce hydrogen for injection into the main furnace 1314. The main furnace 1314 can include any of the furnace embodiments described herein. In some embodiments, the hydrogen introduced by the hydrogen supply can enter the pre-reduction chamber 1313 or the main furnace 1314 without being compressed by the compressor 1315 or preheated by the preheater 1319.

[0097] In the main furnace 1314, pre-reduced iron ore or metal oxides may be reduced by injected hydrogen via hydrogen plasma smelting reduction (HPSR) and / or molecular hydrogen reduction reactions. The reduction product from the main furnace 1314 may be liquid iron / metal or steel. Slag may also be produced from the main furnace 1314, and heat energy from the slag may or may not be recycled.

[0098] To further improve energy efficiency, residual materials from the pre-reduction, HPSR, and / or molecular hydrogen reduction can be recycled. Residual materials may include solids such as unreacted iron ore / metal oxides, as well as off-gases containing unreacted hydrogen, gangue elements, or water vapor. The off-gases can be discharged from the main furnace 1314, where they can pass through a recuperator 1316, where countercurrent heat exchange occurs and / or thermal energy from the off-gases can be recycled. Hydrogen can be discharged from the recuperator 1316 and recycled to the pre-reduction chamber 1313. The thermal energy recovered from the recuperator 1316 can be used to preheat hydrogen from the hydrogen supply or to preheat hydrogen recycled after the pre-reduction chamber 1313.

[0099] The off-gas and residual solids can be discharged from the pre-reduction chamber 1313 and can enter an electrostatic precipitator 1317. The electrostatic precipitator 1317 can be used to separate the residual iron ore / metal oxide from the off-gas or to recycle the residual iron ore / metal oxide and off-gas. The residual iron ore / metal oxide can re-enter the pelletizer 1311. The off-gas exits the electrostatic precipitator 1317 and can enter a scrubber and / or condenser 1318. The scrubber 1318 can separate hydrogen from non-condensable gases. Non-condensable gases may include, but are not limited to, nitrogen and carbon dioxide. The non-condensable gases are discharged through a gas bleed, while recycled hydrogen can enter a compressor 1315 before being injected into the main furnace 1314.

[0100] FIG. 13C illustrates yet another exemplary steelmaking process according to some embodiments of the present disclosure. As shown in FIG. 13C, iron ore or metal oxide can be introduced into a preheater or dryer 1321 to remove excess moisture and / or preheat the material. The iron ore or metal oxide can be introduced directly into the dryer, or in some embodiments, it can be mixed with iron ore dust collected first through a cyclone system 1322 and processed through a scrubber / condenser 1331. The scrubber 1331 may liberate the ore and hydrogen from water vapor, harmful minerals, and / or gases. Harmful materials may include, but are not limited to, gangue elements or oxides such as SiO, CaO, MgO, and / or AlO. Impurity spills can result in the discharge of gangue and other impurities. After the recycle cyclone 1322, the iron ore or metal oxide can be introduced into a seal bin 1323, where the iron ore or metal oxide fines can be mixed with flux. The mixed feedstock can then be introduced into the pre-reduction chamber 1324 to produce pre-reduced iron or pre-reduced metal oxide. Small diameter iron ore fines or metal oxide fines can be recycled via cyclone 1330 and returned to the pre-reduction chamber 1324. For example, the pre-reduction chamber 1324 can be a fluidized bed, a reduction shaft, a cyclone converter, an entrained flow reactor, a countercurrent shaft furnace, or any gas-solid reactor. In some embodiments, the pre-reduction chamber 1324 can include other equipment from a conventional blast furnace or equipment used in a direct reduction of iron (DRI) process, such as a bubbling fluidized bed reactor for reducing fine iron ore. In some embodiments, the pre-reduction chamber 1324 can be incorporated into the main furnace 1325. In some embodiments, the main furnace 1325 may have two compartments, for example, an upper compartment where off-gas flows upward through a shaft at the top of the furnace away from the arc, and iron ore falls through the upper compartment into the lower compartment of the furnace where smelting and the final reduction step of FeO to metallic Fe occur. In some embodiments, these two compartments communicate directly.In other embodiments, there may be a heat exchanger 1328 between the two compartments, for example to reduce the temperature of the off-gas before pre-reducing the metal oxides.

[0101] Hydrogen functions as a reducing gas, and a hydrogen supplier can supply hydrogen gas / molecular hydrogen to the pre-reduction chamber 1324 and the main furnace 1325. The main furnace 1325 can be any of the furnace embodiments described herein. The hydrogen gas / molecular hydrogen can be compressed by a compressor 1327. The compressed hydrogen can enter the main furnace 1325 along with the dried iron ore or metal oxide. In some embodiments, the compressed hydrogen is first preheated 1326 before entering the main furnace 1325. In the pre-reduction chamber 1324, the iron ore or metal oxide can be pre-reduced with hydrogen. In the main furnace 1325, the pre-reduced iron ore or metal oxide, or the iron ore or metal oxide from the dryer 1321, can be reduced by hydrogen plasma smelting (HPSR) and / or molecular hydrogen reduction. HPSR can reduce metal oxides with a lower heat demand than reactions relying solely on molecular hydrogen.

[0102] The reduction product from the main furnace 1325 can be liquid iron / metal, matte, slag, or steel. The reduced product can be transferred to a ladle furnace where the liquid iron / metal or steel can be refined. The slag produced from HPSR and / or molecular hydrogen reduction in the main furnace 1325 can enter a slag granulation system.

[0103] To further improve energy efficiency, residual materials from the pre-reduction chamber 1324 and main furnace 1325 can be recycled. The residual materials may include solids such as unreacted iron ore / metal oxides, as well as off-gas, gangue elements, or water vapor. The off-gas is discharged from the main furnace 1325 and / or pre-reduction chamber 1324, where it can pass through a recuperator 1328. The recuperator 1328 can perform counterflow heat exchange and recycle thermal energy from the off-gas to preheat hydrogen or other reducing gas in a preheater 1326. An electrostatic precipitator 1329 can be used to separate residual iron ore / metal oxide dust from the off-gas after it is discharged from the recuperator 1328.

[0104] The off-gas exits the electrostatic precipitator 1329 and enters the scrubber / condenser 1331 where hydrogen and other gases can be separated from the gangue elements and / or water vapor. After exiting the scrubber 1331, the gas re-enters the compressor 1332 and can be used again in another reduction reaction in the pre-reduction chamber 1324.

[0105] definition Unless otherwise defined, all terminology, notation, and other technical and scientific terms used herein shall have the same meaning as commonly understood by one of ordinary skill in the art to which the claimed subject matter pertains. In some instances, terms having a commonly understood meaning are defined herein for clarity and / or ease of reference, and the inclusion of such definitions herein should not necessarily be construed as representing a substantial difference from what is commonly understood in the art.

[0106] References herein to "about" a value or parameter include (and account for) variations on the value or parameter itself. For example, a statement of "about X" includes a statement of "X." Furthermore, references to the terms "less than," "greater than," "up to," "at least," "less than or equal to," "greater than or equal to," or other similar terms following a string of values or parameters are meant to apply the term to each value or parameter in the string of values or parameters.

[0107] As used herein, the singular forms "a," "an," and "the" are intended to include the plural forms unless the context clearly indicates otherwise. Also, as used herein, the term "and / or" should be understood to refer to and encompass any and all possible combinations of one or more of the associated listed items. Furthermore, as used herein, the terms "includes," "including," "comprises," and / or "comprising" should be understood to specify the presence of stated features, integers, steps, operations, elements, components, and / or units, but do not exclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and / or groups thereof.

[0108] This application discloses several numerical ranges in the text and figures, and the disclosed numerical ranges inherently support any range or value within the disclosed numerical range, including the endpoints, since the disclosure can be practiced throughout the disclosed numerical range, even if an exact range limitation is not literally written herein.

[0109] The above description is presented to enable any person skilled in the art to make and use the disclosure, and is provided in the context of a particular application and its requirements. Various modifications to the preferred embodiment will be readily apparent to those skilled in the art, and the general principles defined herein may be applied to other embodiments and applications without departing from the spirit and scope of the disclosure. Thus, the present disclosure is not intended to be limited to the embodiments shown, but is to be accorded the widest scope consistent with the principles and features disclosed herein.

Claims

1. A method for forming molten metal, Introducing ore containing metal oxides into the furnace through a supply port located on at least one of the roof or side of the furnace, Maintaining a molten bath in the furnace that includes a slag layer containing the metal oxide and a metal layer containing molten metal and positioned below the slag layer, Introducing a gaseous fluid into the furnace via a plurality of injectors located on at least one of the roof or side surfaces of the furnace, A method comprising reducing the metal oxide in the slag layer with the gaseous fluid to produce the molten metal.

2. The method according to claim 1, wherein the gaseous fluid is introduced into the molten bath.

3. The method according to claim 2, wherein the gaseous fluid is introduced into the slag layer of the molten bath.

4. The method according to claim 2, wherein the gaseous fluid is introduced into the metal layer of the molten bath, and because the metal layer has a lower viscosity than the slag layer, the diameter of bubbles formed from the injected gaseous fluid is reduced.

5. The method according to any one of claims 1 to 2, wherein the gaseous fluid is introduced into the internal axis at an angle of less than 90 degrees with respect to the line tangent to each injector in the cross-section of the shell furnace.

6. The method according to any one of claims 1 to 2, wherein the gaseous fluid is introduced, the gaseous fluid agitates the molten bath in the furnace to produce a homogeneous slag composition, and the separation of the metal contained in the slag layer is promoted such that the metal accumulates in the metal layer below the slag layer.

7. The method according to any one of claims 1 to 2, wherein the fluid is introduced in such a way that the molten bath swirls within the furnace.

8. The method according to any one of claims 1 to 2, wherein the gaseous fluid includes hydrogen gas.

9. The method according to any one of claims 1 to 2, further comprising generating an electric arc between at least a first electrode from one or more electrodes extending from the roof of the furnace toward the lower part of the furnace and at least a second electrode from one or more electrodes located in the lower part of the furnace, wherein the electric arc is configured to melt the metal oxide or to supply thermal energy to the bath.

10. The method according to claim 9, wherein the electric arc is located between at least one of the first electrode or the second electrode and the molten bath of the furnace.

11. The method according to claim 9, further comprising introducing the gaseous fluid into the furnace through a port passing through the central axis of at least one of the first electrode or the second electrode.

12. The method according to claim 9, further comprising generating a plasma from the introduced gaseous fluid and the electric arc.

13. The method according to claim 9, wherein the electric arc agitates the molten bath.

14. The furnace includes a plurality of supply ports, The method according to claim 9, further comprising introducing more metal oxides into the furnace through a supply port closer to the center of the roof than through a supply port further from the center of the roof.

15. The method according to any one of claims 1 to 2, wherein the metal oxide comprises at least one of iron ore, iron oxide, hematite, magnetite, iron oxide-containing waste stream, or a combination thereof.

16. The method according to claim 15, wherein the metal oxide comprises iron ore, and the iron ore is in the form of at least one of fine powder, lumps, pellets, sintered products, or a mixture of metal oxides.

17. The method according to any one of claims 1 to 2, wherein the molten metal includes metallic iron.

18. The method according to any one of claims 1 to 2, further comprising introducing a carbon source into the furnace via the supply port or at least one of the plurality of injectors.

19. The method according to claim 18, wherein the carbon source includes natural gas used to carbonize the molten metal and / or to reduce the metal oxide in the slag layer.

20. The method according to any one of claims 1 to 2, wherein the furnace is a DC or AC electric arc furnace.

21. The method according to any one of claims 1 to 2, wherein the method operates in batch mode, continuous mode, or semi-continuous mode.

22. The method according to claim 21, wherein the metal is extracted semi-continuously, and the slag layer is extracted semi-continuously or processed in a batch manner by increasing the gas fluid injection to reduce the metal oxide in the slag layer.

23. The method according to any one of claims 1 to 2, wherein the molten metal oxide is reduced via a reduction reaction, which is mainly operated when the concentration of the metal oxide in the slag layer is high, thereby improving the hydrogen utilization rate of the process.

24. A furnace for the production of molten metal, A shell having an upper and a lower part, comprising a plurality of injectors configured to inject a gaseous fluid into the furnace, A roof connected to the upper part of the shell, wherein the shell and / or the roof has a plurality of supply ports configured to introduce molten metal oxide into the furnace, The shell comprises a hearth connected to the lower part of the shell, A furnace for producing molten metal, wherein the furnace is configured to maintain the molten metal oxide in a molten state, and the gaseous fluid reduces the molten metal oxide to molten metal.

25. The furnace according to claim 24, wherein at least one of the plurality of injectors is configured to inject the gaseous fluid into the molten metal oxide.

26. The furnace according to any one of claims 24 to 25, wherein the gaseous fluid includes hydrogen gas, a hydrogen-containing gas, a carbon-containing gas, or a combination thereof.

27. ​​The furnace according to any one of claims 24 to 25, wherein the plurality of injectors include a plasma torch, and the plasma torch is configured to inject a gaseous fluid at a temperature higher than the melting point of the metal oxide.

28. The furnace according to any one of claims 24 to 25, wherein the roof comprises at least one electrode extending from the roof toward the hearth of the furnace, the hearth comprises at least one counter electrode, and the furnace is configured to generate an electric arc between the distal end of the at least one electrode and the at least one counter electrode.

29. At least a portion of the gaseous fluid injected into the furnace passes through the electric arc that forms the plasma. The furnace according to claim 28, wherein the plasma maintains the molten metal oxide and / or molten metal in a molten state, supplies thermal energy to the furnace, supplies ionized gas to the molten metal oxide and / or molten metal, and reduces the molten metal oxide.

30. The furnace according to any one of claims 24 to 25, wherein the molten metal oxide comprises iron oxide, hematite, magnetite, or a combination thereof.

31. The furnace according to any one of claims 24 to 25, wherein the gaseous fluid is injected in combination with a solid such as a flux or fine metal oxide, the flux or fine metal oxide acting as bubble nucleation sites for the injected gaseous fluid and increasing the surface area of ​​the reaction between the gaseous fluid and the metal oxide in the slag layer.

32. A method for forming molten metal, Introducing iron ore containing metal oxides into the furnace via multiple supply ports, Maintaining a molten bath in the furnace that includes a slag layer containing the metal oxide and a metal layer containing molten metal and positioned below the slag layer, An electric arc is generated between the first electrode and the second electrode to melt the metal oxide, or to supply thermal energy to the molten metal. A method comprising introducing natural gas into the furnace via a plurality of injectors to reduce metal oxides in the slag layer to produce the molten metal.

33. The method according to claim 32, wherein the natural gas is introduced into the slag layer of the melting bath.

34. The method according to claim 32, wherein the natural gas is introduced into the metal layer of the melting bath, and the diameter of the bubbles formed from the injected natural gas is reduced because the metal layer has a lower viscosity than the slag layer.

35. The method according to claim 32, wherein the plurality of injectors are configured to inject the natural gas and the molten bath swirls in the furnace.

36. The method according to claim 32, wherein natural gas is introduced, the natural gas agitates the molten bath in the furnace to produce a homogeneous slag composition, and promotes the separation of metals contained in the slag layer such that the metals accumulate in the metal layer below the slag layer.

37. The method according to claim 32, wherein the natural gas includes hydrogen gas.

38. The method according to claim 32, wherein the electric arc is located between at least one of the first electrode or the second electrode and the molten bath of the furnace.

39. The method according to claim 32, further comprising introducing the natural gas into the furnace through a port passing through at least one central axis of the first electrode or the second electrode.

40. The method according to claim 32, wherein the metal oxide comprises iron ore.

41. The method according to claim 40, wherein the iron ore is in the form of at least one of fine powder, lumps, pellets, sintered products, or a mixture of metal oxides.

42. The method according to claim 32, wherein the furnace is a DC or AC electric arc furnace.

43. A method for forming molten metal, Introducing metal oxides into the furnace through multiple supply ports, Maintaining a molten bath in the furnace comprising a slag layer containing molten metal oxide and a metal layer containing molten metal and positioned below the slag layer, A method comprising introducing a gaseous fluid into the furnace via a plurality of injectors, wherein the gaseous fluid is injected into the molten bath to generate gas bubbles in the slag that increase the surface area of ​​the reaction between the gaseous fluid and the metal oxide in the slag layer, which reduces the molten metal oxide to produce the molten metal.

44. The method according to claim 43, wherein the gaseous fluid is introduced into the slag layer of the molten bath.

45. The method according to claim 43, wherein the gaseous fluid is introduced, and the gaseous fluid stirs the molten bath in the furnace to produce a homogeneous slag composition, and promotes the separation of the metal contained in the slag layer such that the metal accumulates in the metal layer below the slag layer.

46. The method according to claim 43, wherein the gaseous fluid is introduced and the molten bath swirls in the furnace.

47. The method according to claim 43, wherein the gaseous fluid includes hydrogen gas.

48. The method according to claim 43, wherein the gaseous fluid includes natural gas.

49. The method according to claim 43, further comprising generating an electric arc between a first electrode and a second electrode, wherein the electric arc is configured to melt the metal oxide or to supply thermal energy to the molten bath.

50. The method according to claim 49, wherein the electric arc is located between at least one of the first electrode and / or the second electrode and the molten bath of the furnace.

51. The method of claim 48, further comprising introducing the gaseous fluid into the furnace through (1) a port passing through at least one central axis of the first electrode or the second electrode, or (2) a plurality of injectors arranged on the side of the furnace.

52. The method according to claim 50, further comprising generating a plasma from the introduced gaseous fluid and the electric arc.

53. The method according to claim 49, wherein the electric arc agitates the molten bath.

54. The method according to claim 43, wherein the metal oxide comprises iron ore, and the iron ore is in the form of at least one of fine powder, lumps, pellets, sintered products, or a mixture of metal oxides.

55. The method according to claim 43, wherein the molten metal includes metallic iron.

56. The method according to claim 43, wherein the furnace is a DC or AC electric arc furnace.

57. The method according to claim 43, wherein the metal layer is removed semi-continuously, and the slag layer is removed semi-continuously or processed in batches by increasing the gas fluid injection to reduce the metal oxide in the slag layer.

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