Method and apparatus for producing metal, alloy, matte or enriched and cleaned slag from predominantly oxide feedstock

Abstract

Steel production systems and methods are described, as well as furnaces and methods of producing steel using such furnaces. In some embodiments, an oven may include a housing having a top portion and a bottom portion. There may be a furnace top connected to the top portion, which may have a feed port for introducing a metal oxide into the furnace. The housing may include an injector that may inject fluid into the furnace. The bottom portion may be connected to a hearth. The furnace may melt the metal oxide to form a molten bath in the hearth. The melt bath may have a slag layer and a metal layer. The fluid may reduce metal oxides in the slag layer to form molten metal.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This application claims the benefit of U.S. Provisional Application No. 63 / 391,679, filed on July 22, 2022, the entire contents of which are hereby incorporated by reference. Technical Field

[0003] The present disclosure relates generally to the production of metals, alloys (including steel and ferroalloys), matte and enriched or cleaned slags from predominantly oxide feeds, and methods of producing metals, alloys, matte and enriched and cleaned slags, and more particularly to an integrated process having a smelting reduction furnace, and methods of producing metals, alloys, matte and enriched and cleaned slags using such a furnace, with reduced CO2 emissions compared to coal-based processes. Background Art

[0004] Feeds that are primarily oxides (which are sometimes in molten form) are used as raw materials to produce many metals, alloys, mattes, and enriched or cleaned slags. Metals produced from oxide and / or carbonate feeds include tin, lead, iron, chromium, and silicon. Alloys produced from oxide and / or carbonate feeds include steel, ferroalloys (such as ferrochrome, ferronickel, and ferrosilicon) and non-ferrous alloys (such as brass and bronze). Mattes produced from oxide and / or carbonate feeds include copper, nickel, and cobalt mattes for subsequent processing. Enriched and clean slags produced from oxide and / or carbonate feeds include titanium dioxide slags (for subsequent production of titanium dioxide powder) and slags from oxidation processes (such as flash smelting or steelmaking processes or highly reducing slag fuming processes for copper and nickel production).

[0005] As an example of an existing process for producing steel from a predominantly oxide feed, primary steel is produced primarily by converting agglomerated iron ore into molten carbon-excess pig iron or hot metal via a blast furnace (BF), which is then converted into steel via a basic oxygen furnace (BOF) and subsequently subjected to a ladle metallurgical refining step, followed by casting. Roughly 75% of steel is produced via the blast furnace and basic oxygen furnace routes, and each metric ton of crude steel produced generates approximately 1.85 metric tons of CO2 (t CO2 / t CS ) to 2.2t CO2 / t CS. The production of steel produces approximately 11% of the world's total CO2 emissions. Converting iron ore into molten steel via the BF-BOF route requires five steps, including coke manufacturing, preparation of iron ore by sintering or pelletizing. The blast furnace is the most carbon-intensive step in primary steelmaking. In a separate step, coal is converted into metallurgical coke, which is then introduced into the blast furnace to reduce the iron ore and provide the heat required for melting by burning with hot air blown into the furnace. At the bottom of the blast furnace, carburized molten metallic iron and slag floating on the metallic iron are collected. The slag layer consists of gangue elements present in the iron ore. Although hydrogen can be injected into the blast furnace to replace some of the coke, the process is not optimized for direct hydrogen reduction, resulting in low hydrogen utilization, minimal reduction in CO2 emissions (roughly 20%), and a significant negative impact on the BF thermal profile. The downstream BOF process reduces the carbon content of the hot metal from the BF from 3-4% to 1% by injecting high purity oxygen into the hot metal, removes unwanted impurities, and refines pig iron and scrap into steel to the desired composition.

[0006] An alternative technology for producing virgin iron is direct reduced iron (DRI) in a shaft furnace or fluidized bed reactor, which uses carbon monoxide and hydrogen as a reducing gas mixture. Typically, the reducing gas mixture is sourced from natural gas or coal. Iron ore pellets or iron ore fines, depending on the specific DRI process, are directly reduced in the solid state in the DRI reactor. The reaction temperature in the DRI process is well below the melting point of iron and is typically below about 800°C to avoid problems with sintering and agglomeration of iron ore pellets. The process produces sponge iron, a highly reactive and porous solid product that must then be used in adjacent steel production processes to avoid excessive reoxidation, or briquetted while it is still hot to produce hot briquetted iron (HBI), which can be shipped globally.

[0007] There is work underway to commercialize the replacement of the carbon monoxide-hydrogen mixture in the DRI process with pure hydrogen, although most technologies attempt to include some carbon monoxide or a carbon source (such as natural gas and methane) to exothermically provide heat for the endothermic reaction of molecular hydrogen with iron oxide and / or to at least partially carburize the DRI / HBI product so that the carbon can provide "fuel" for partial downstream removal to make steel.

[0008] DRI / HBI must be melted and converted into steel by BOF or electric arc furnace (EAF). EAF uses electric arc to melt charged materials such as DRI / HBI and / or cast iron ingots (or pig iron) and scrap steel, and then keeps the top slag layer and the bottom metal layer molten in the subsequent refining process to produce steel. EAF is usually used to process scrap iron into secondary steel, and DRI / HBI or cast iron is used to dilute impurities in scrap iron, which limit the steel grade to be produced in secondary steelmaking. However, some EAFs now mainly use DRI / HBI and some cast iron to make higher quality steel to meet more demanding applications. In order to make DRI / HBI compatible with existing EAF processes and technologies, high-grade iron ore (usually containing 65+% iron) must be used in the DRI process, thereby limiting the amount of gangue elements present in DRI / HBI. In DRI, since the process occurs in the solid state, gangue elements such as silicon and aluminum in the form of oxides are not removed as separate slag phases as in BF or BOF. In addition, the degree of metallization of iron in DRI is generally limited to about 90%, and the remaining unreduced iron remains in the DRI in the form of wüstite (FeO), which also forms slag when melted. Therefore, in the subsequent melt phase oxidation process in the EAF or BOF, if the DRI contains elevated levels of gangue and the slag contains high levels of FeO due to the chemical balance between the steel produced by oxidation of carbon in the iron-based phase and the slag, a large amount of slag is produced.

[0009] In recent years, it has been proposed to add a furnace between the DRI process and the EAF or BOF, such as the large submerged arc furnace (SAF) used by New Zealand Steel. The added furnace melts the DRI and separates the gangue elements and the remaining unreduced FeO from the metallic iron. In order to produce molten pig iron and low-iron slag suitable for existing steelmaking processes, a sufficient amount of reducing agent must be added to the furnace. The reducing agent is currently some form of solid carbon. Most of this carbon is then blown out of the pig iron to form steel, resulting in GHG emissions.

[0010] As an example of an existing process for producing metal from a feed that is mainly oxide, a multi-stage process with smelting, slag reduction and slag fuming stages is used to reduce smelt tin concentrates mainly containing cassiterite to produce crude tin and discard slag. Top-immersion lance (TSL) furnaces are the main technology for tin production, having replaced reverberatory furnaces and electric smelting furnace technologies. Silicon metal and many ferroalloys are produced by smelting and reducing feeds that are mainly oxides in large EAFs. Some of these processes include calcination and / or pre-reduction steps before the EAF. Due to the increase in the recovery of chromium when reducing smelting chromite ore in a direct current (DC) furnace, ferrochrome production is turning from alternating current (AC) furnace technology (usually running in an immersion or brush arc mode) to a DC furnace. When processing slightly sulfided ores (such as some nickel laterite smelting in Indonesia), when smelting calcined concentrates with residual sulfur content, or when reducing slags with elevated copper, nickel or cobalt content from upstream oxidative pyrometallurgical processes, matte is usually produced in the smelting reduction furnace. Titanium ores can be upgraded by removing iron in a reduction smelting process after preheating and reduction of the ore to char in a rotary kiln, as practiced in Canada, South Africa, Norway and China. Slags can also be cleaned by reducing dissolved oxide species into a molten collection phase below the slag or by reducing or evaporating dissolved oxide species into a furnace freeboard gas phase above the slag. Examples include reducing slags with elevated cobalt or silver content and reducing slags with elevated zinc, lead and tin, respectively.

[0011] The hydrogen plasma smelting reaction (HPSR) described herein is a smelting reduction reaction that produces a molten alloy, matte, or vapor phase from a mixture of metal oxides or a mixture consisting primarily of metal oxides and some sulfur content by utilizing the high temperatures of ionized hydrogen and hydrogen plasma and molecular hydrogen gas injected into the molten phase in the slag layer or below the slag. The ionized hydrogen and molecular hydrogen gas create highly reducing conditions in the slag and / or surrounding environment, allowing many chemical reduction reactions to occur. These reactions may not be as favorable in the presence of molecular hydrogen, and ionized hydrogen changes the Gibbs free energy of the reaction to more favorable thermodynamic conditions. In addition, the main furnace described herein contains an embodiment in which an electric arc is used to generate thermal energy for smelting, because molecular hydrogen and / or hydrogen plasma is used for reduction reactions of metal oxides.

[0012] When applied to steel production, HPSR contributes to a method of producing steel from iron ore with minimal CO2 emissions by utilizing the ionized state of hydrogen to reduce iron ore. The reduction potential of hydrogen ions is 3 to 15 times higher than that of reducing iron ore using neutral species (e.g., molecular hydrogen through DRI). Reducing iron ore by hydrogen plasma and / or molecular hydrogen can simplify the process, and it is possible to choose to produce molten steel from iron ore in a single furnace, thereby eliminating the two separate steps of reduction and refining, and there is no need to pre-agglomerate, pelletize or upgrade the iron ore. HPSR furnaces developed so far inject hydrogen through a plasma torch, inject hydrogen into the surrounding gas environment through the upper furnace shell, or inject hydrogen through the center of the electrode. Existing HPSR furnaces also introduce iron ore through the center of the electrode for in-flight reduction, or introduce iron ore to the bottom of the furnace in a batch process, which will limit the surface area of ​​the reduction reaction and thus limit the output of the process. Summary of the invention

[0013] The present disclosure relates to the production of metals, alloys, matte and enriched or clean slag, including the production of the aforementioned metals and alloys (e.g., copper, iron, steel, ferrochrome, nickel, etc.). A furnace and a method for producing steel using such a furnace are described herein, but the method can be applied to the production of other alloys, metals, matte and clean slag, as will be understood by those skilled in the art. Fine iron ore, sintered iron ore or lump iron ore or metal oxide can be added to the furnace from one or more feed ports on the furnace top and / or furnace wall (e.g., shell). The feed port can be located near the electrode and around the furnace top circumference. This configuration can help align the high temperature area in the furnace with the feed path of the iron ore or metal oxide, which can lead to improved productivity and reduced operating costs, and help protect the furnace wall from arc radiation and splashing of the molten pool. In some embodiments, the furnace can be operated with continuous discharge (tapping) or batch discharge, thereby improving energy efficiency. In some embodiments, the components of the furnace described herein can be compatible with commercial EAFs, so that the EAF can be modified with these components to perform HPSR and / or molecular hydrogen reduction reactions.

[0014] In some embodiments, a reducing fluid (e.g., hydrogen) can be sprayed by an electrode or near an electrode to produce hydrogen plasma. In some embodiments, hydrogen can be sprayed and / or bubbled by the bottom of a furnace. In some embodiments, hydrogen can enter by a supersonic or coherent jet located on the top of a furnace and the side of a furnace. In some embodiments, hydrogen can enter the slag and molten metal bath region of a furnace, where a reduction reaction can occur. These hydrogen injection patterns can increase the reduction reaction area and generate bath stirring, which can increase the reduction reaction rate and can increase the hydrogen utilization rate. After hydrogen is injected into a metal layer and / or slag layer, the jet of hydrogen can diffuse into hydrogen bubbles. The pattern of hydrogen injection can be selected to maximize the dispersion of hydrogen bubbles, optimize the diameter of hydrogen bubbles to increase the reduction reaction surface area between metal oxides and hydrogen, and / or optionally generate foamy slag so that the volume in which a reduction reaction occurs is maximized. In addition, the generation of foamy slag by hydrogen injection can protect the top of a furnace from the influence of molten bath radiation, thereby reducing the heat loss of the system. In some embodiments, the injected molecular hydrogen or hydrogen mixture produces a partial hydrogen atmosphere in a furnace. At the arc, hydrogen is ionized, thereby generating a hydrogen plasma that can participate in the reduction reaction of the metal oxide.

[0015] In some embodiments, a furnace for molten metal production comprises: a shell or multiple walls having a top portion and a bottom portion, and the shell or multiple walls include multiple injectors configured to inject fluid into the furnace; a furnace top connected to the top portion of the shell or multiple walls, and the shell, multiple walls and / or furnace top include multiple feed ports configured to introduce metal oxides into the furnace; and a hearth connected to the bottom portion of the shell or multiple walls, and the furnace is configured to melt the metal oxide to form a molten bath, the molten bath comprising a slag layer containing molten metal oxides and a metal layer containing molten metal below the slag layer, and the fluid reduces the molten metal oxides in the slag layer to molten metal. In some embodiments, the multiple injectors are configured to inject fluid toward a working area of ​​the molten bath, and there are metal oxides. In some embodiments, the first injector in the multiple injectors is configured to inject fluid toward an area of ​​the molten bath. In some embodiments, the second injector in the multiple injectors is configured to inject fluid toward a second area of ​​the molten bath that is different from the first area of ​​the molten bath. In some embodiments, at least one of the multiple injectors is configured to inject fluid into the molten bath. In some embodiments, at least one of the multiple injectors is configured to inject fluid into the slag layer of the molten bath. In some embodiments, at least one of the multiple injectors is an injector immersed in the molten bath. In some embodiments, at least one of the multiple injectors is an injector immersed in the slag layer. In some embodiments, at least one of the multiple injectors is an injector immersed in the molten bath and in contact with both the slag layer and the metal layer. In some embodiments, the shell or multiple walls have an internal axis, and the multiple injectors are configured to inject fluid at an angle of less than 90 degrees relative to the cross-section of the shell or multiple walls perpendicular to the internal axis and tangent to each injector. In some embodiments, the furnace top includes a second multiple injector configured to inject fluid into the furnace. In some embodiments, the multiple injectors are configured to inject fluid so that the fluid stirs the slag layer and / or metal layer in the furnace. In some embodiments, the plurality of injectors are configured to inject fluid so that the slag layer and / or metal layer of the molten bath swirls in the furnace. In some embodiments, the plurality of injectors are spaced equidistantly around the circumference or multiple walls of the shell. In some embodiments, the fluid includes hydrogen, hydrogen-containing gas, carbon-containing gas or a combination thereof. In some embodiments, the plurality of injectors include at least one of a spray gun, a submerged tuyeres, a swirl gun (such as a top-immersion spray gun), a supersonic jet, a coherent jet, a plasma torch or any type of injector that maximizes the contact area between the injection fluid and the slag layer. In some embodiments, the plasma torch injects 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 furnace top includes at least one electrode extending from the furnace top toward the furnace bed, and the furnace bed includes at least one counter electrode, and the furnace is configured to generate an arc between the distal end of the at least one electrode and the at least one counter electrode. In some embodiments, the arc is between the distal end of the at least one electrode and the molten bath of the furnace. In some embodiments, the distal end of the at least one electrode is above the slag layer of the molten bath. In some embodiments, the distal end of the at least one electrode is immersed in the slag layer and / or metal layer of the molten bath. In some embodiments, the at least one counter electrode is embedded in the furnace bed. In some embodiments, the arc is a transfer or non-transfer arc. In some embodiments, the arc is configured to melt metal oxides. In some embodiments, under AC or DC operation, at any given time, the at least one electrode is a cathode and the at least one counter electrode is an anode. In some embodiments, the at least one electrode includes a port that runs through the central axis of the at least one electrode. In some embodiments, the fluid is injected into the furnace through the port of the at least one electrode. In some embodiments, the electrode is solid and the fluid is injected only through the multiple injectors. In some embodiments, at least a portion of the fluid injected into the furnace passes through the arc to form plasma. In some embodiments, the plasma melts the metal oxide, keeps the metal layer and the slag layer in the molten phase, supplies heat energy to the furnace, supplies ionized gas to the molten bath, and / or reduces the metal oxide. In some embodiments, the furnace top includes a plurality of electrodes extending from the furnace top toward the furnace bed, and the furnace is configured to generate an arc between the distal end of each electrode of the plurality of electrodes and the at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that there is no arc interference between each electrode and the arc of the at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that there is arc interference between each electrode and the arc of the at least one counter electrode, so that the arc merges toward the center of the molten bath. In some embodiments, the at least one electrode and / or the at least one counter electrode include graphite, titanium, tungsten, tantalum, zirconium or copper. In some embodiments, the arc stirs the molten bath. In some embodiments, the plurality of feed ports are configured so that feed ports closer to the center of the furnace top introduce more metal oxides into the furnace than feed ports farther from the center of the furnace top. In some embodiments, the suitability of the metal oxides for the method is determined by the thermodynamic potential for reduction of the injected fluid and / or ionized fluid, such as iron oxides, chromium oxides, nickel oxides, copper oxides, and phosphorus oxides in embodiments where ionized hydrogen and / or molecular hydrogen is present. In some embodiments, the metal oxides include 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 include at least one heat exchanger. In some embodiments, the 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 the most advanced technology for enhancing furnace integrity. In some embodiments, the multiple injectors are configured to inject flux sources or metal oxides into the furnace. In some embodiments, fluid and solid such as flux or fine metal oxide combination injection, and flux or injected metal oxides serve as bubble nucleation points of injected gas to increase the reaction surface area between the metal oxides in the fluid and 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, a solid carbon source is injected into a metal bath for carburization. In some embodiments, the carburization of the molten metal is carried out in a downstream ladle metallurgical process.

[0016] In some embodiments, the method of forming molten metal includes: introducing metal oxide or metal mixture into the furnace through multiple feed ports in the furnace top and / or furnace side; melting metal oxide in the furnace to form a molten bath, the molten bath including a slag layer containing molten metal oxide and a metal layer containing molten metal below the slag layer; introducing a fluid into the furnace through multiple injectors in the furnace side, and 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 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, and the metal layer has a lower viscosity than the slag layer and thus causes a reduced bubble diameter to be formed from the injected fluid. In some embodiments, the fluid is introduced at an angle of less than 90 degrees to a line tangent to each injector relative to a cross section of the shell or multiple walls perpendicular to the internal axis. In some embodiments, the fluid is introduced so that the fluid stirs the molten bath in the furnace to produce a uniform slag composition and enhance the separation of metal particles (metallics) contained in the slag, so that the metal particles gather in the metal layer below the slag layer. In some embodiments, the fluid is introduced so that the molten bath swirls in the furnace. In some embodiments, the multiple injectors are spaced equidistantly around the circumference or multiple walls of the shell. In some embodiments, the fluid comprises hydrogen. In some embodiments, the method includes generating an arc between the far end of at least one electrode extending from the furnace top toward the furnace bottom and at least one counter electrode at the furnace bottom, and the arc is configured to melt metal oxides or provide thermal energy to the molten bath. In some embodiments, the arc is between the far end of the at least one electrode and the molten bath of the furnace. In some embodiments, the method includes introducing a fluid into the furnace through a port running through the central axis of the at least one electrode. In some embodiments, the method includes generating plasma from the introduced fluid and the arc. In some embodiments, the arc stirs the molten bath. In some embodiments, the method includes introducing more metal oxides into the furnace through a feed port closer to the center of the furnace top than a feed port farther from the center of the furnace top. In some embodiments, the metal oxide comprises iron ore. In some embodiments, the metal oxide comprises iron oxide, hematite, magnetite, a waste stream containing iron oxide, or a combination thereof. In some embodiments, the iron ore is in the form of fines, blocks, pellets, sintered materials and / or a mixture of metal oxides. In some embodiments, the molten metal comprises metallic iron. In some embodiments, the method includes introducing a carbon source into the furnace through the multiple feed ports and / or through the multiple injectors. In some embodiments, the carbon source is a solid carbon source for carburizing metallic iron.In some embodiments, any fluid injected into the slag layer will partially escape without reducing iron ore. In some embodiments, the fluid escaping from the slag layer generates plasma around the arc. In some embodiments, the ionized fluid around the arc is sucked into the slag layer by the arc momentum. In some embodiments, the ionized fluid reduces the metal oxides in the slag layer near the arc. In some embodiments, the ionized fluid around the arc becomes non-ionized, thereby promoting the heat generation in the furnace in an exothermic manner. In some embodiments, the furnace is a DC or AC arc furnace. In some embodiments, the method is operated in batch, continuous or semi-continuous mode. In some embodiments, metal is continuously discharged (tap), and slag with high metal oxide content can be processed in batches by increasing fluid injection to reduce the metal oxide in the slag. In some embodiments, the first furnace produces slag and metal layer with high metal oxide content, and the second furnace is connected to the first furnace to receive the slag. In some embodiments, the second furnace includes a method for reducing the metal oxide contained in the slag. In some embodiments, the reduction reaction is mainly carried out under high levels of metal oxides in the slag layer to improve the hydrogen utilization rate of the process. In some embodiments, prior to tapping the slag, injection of reducing agent is increased to reduce the level of metal oxides in the slag before tapping.

[0017] In some embodiments, a furnace for molten metal production comprises: a shell or multiple walls having a top portion and a bottom portion, wherein the shell or multiple walls include multiple injectors configured to inject fluid into the furnace; a furnace top connected to the top portion of the shell or multiple walls, wherein the shell or multiple walls and / or the furnace top include multiple feed ports configured to introduce molten metal oxide into the furnace; and a furnace bed connected to the bottom portion of the shell or multiple walls, wherein the furnace is configured to maintain the molten metal oxide in its molten state and the fluid reduces the molten metal oxide to molten metal. In some embodiments, the multiple injectors are configured to inject fluid toward the molten metal oxide. In some embodiments, the first injector of the multiple injectors is configured to inject fluid toward an area of ​​the molten metal oxide. In some embodiments, the second injector of the multiple injectors is configured to inject fluid toward a second area of ​​the molten metal oxide that is different from the first area of ​​the molten metal oxide. In some embodiments, at least one of the multiple injectors is configured to inject fluid into the molten metal oxide. In some embodiments, the at least one of the multiple injectors is an injector immersed in the molten metal oxide. In some embodiments, at least one of the multiple injectors is an injector immersed in the molten metal. In some embodiments, at least one of the multiple injectors is an immersion injector in contact with both the molten metal oxide and the molten metal. In some embodiments, the shell or multiple walls have an internal axis, and the multiple injectors are configured to spray fluid at an angle of less than 90 degrees relative to the cross section of the shell or multiple walls perpendicular to the internal axis and tangent to each injector. In some embodiments, the furnace top includes a second plurality of injectors configured to spray fluid into the furnace. In some embodiments, the multiple injectors are configured to spray fluid so that the fluid stirs the molten metal oxide and / or molten metal in the furnace. In some embodiments, the multiple injectors are configured to spray fluid so that the molten metal oxide and / or molten metal swirl in the furnace. In some embodiments, the multiple injectors are equidistantly spaced around the circumference of the shell or multiple walls. In some embodiments, the fluid comprises hydrogen, hydrogen-containing gas, carbon-containing gas or a combination thereof. In some embodiments, the plurality of injectors include at least one of a lance, a submerged tuyeres, a swirl lance (such as a top-immersion 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 above 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 an enveloped flame.In some embodiments, the furnace top includes at least one electrode extending from the furnace top toward the furnace bed, and the furnace bed includes at least one counter electrode, wherein the furnace is configured to generate an arc between the distal end of the at least one electrode and the at least one counter electrode. In some embodiments, the arc is between the distal end of the at least one electrode and the molten metal oxide and / or molten metal of the furnace. In some embodiments, the distal end of the at least one electrode is above the molten metal oxide. In some embodiments, the distal end of the at least one electrode is immersed in the molten metal oxide and / or molten metal. In some embodiments, the at least one counter electrode is embedded in the furnace bed. In some embodiments, the arc is a transfer or non-transfer arc. In some embodiments, under AC or DC operation, at any given time, the at least one electrode is a cathode and the at least one counter electrode is an anode. In some embodiments, the at least one electrode includes a port running through the central axis of the at least one electrode. In some embodiments, the fluid is ejected into the furnace through the port of the at least one electrode. In some embodiments, the electrode is solid and the fluid is ejected only through the multiple injectors. In some embodiments, at least a portion of the fluid ejected into the furnace passes through the arc to form plasma. In some embodiments, the plasma maintains the molten metal oxide and / or the molten metal in its molten state, supplies heat energy to the furnace, supplies ionized gas to the molten metal oxide and / or the molten metal, and / or reduces the molten metal oxide. In some embodiments, the furnace top includes a plurality of electrodes extending from the furnace top toward the hearth, wherein the furnace is configured to generate an arc between the distal end of each electrode of the plurality of electrodes and the at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that there is no arc interference between the arc of each electrode and the at least one counter electrode. In some embodiments, the distance between the plurality of electrodes is such that there is arc interference between the arc of each electrode and the at least one counter electrode, so that the arc merges toward the center of the molten metal oxide. In some embodiments, the at least one electrode and / or the at least one counter electrode comprises graphite, titanium, tungsten, tantalum, zirconium or copper. In some embodiments, the arc stirs the molten metal oxide. In some embodiments, the plurality of feed ports are configured so that the feed port closer to the center of the furnace top introduces more molten metal oxide into the furnace than the feed port farther from the center of the furnace top. In some embodiments, the suitability of the molten metal oxide for the method is determined by the thermodynamic potential for reduction of the injected fluid and / or ionized fluid, such as iron oxides, chromium oxides, nickel oxides, copper oxides, and phosphorus oxides in embodiments where ionized hydrogen and / or molecular hydrogen is 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 include at least one heat exchanger. In some embodiments, the at least one heat exchanger includes water cooling. In some embodiments, the shell or multiple walls include water-cooled copper. In some embodiments, the inside of the shell or multiple walls includes a castable refractory lining or the most advanced technology for enhancing furnace integrity. In some embodiments, the multiple injectors are configured to inject flux sources or metal oxides into the furnace. In some embodiments, fluid and solid such as flux or fine metal oxide combination injection, wherein the flux or the injected metal oxide serves as the bubble nucleation point of the injection gas to increase the reaction surface area between the metal oxide in the fluid and 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, a solid carbon source is injected into a metal bath for carburization. In some embodiments, the carburization of the molten metal is carried out in a downstream ladle metallurgical process.

[0018] In some embodiments, the method includes introducing molten metal oxide into the furnace through a plurality of feed ports in the furnace top and / or the furnace side; maintaining the molten metal oxide in the furnace in its molten state; and introducing a fluid into the furnace through a plurality of injectors in the furnace side, wherein the fluid reduces the molten metal oxide to molten metal. In some embodiments, the fluid is introduced in the direction toward the molten metal oxide in the furnace. In some embodiments, the fluid is introduced toward the adjacent injectors. In some embodiments, the fluid is introduced into the molten metal oxide. In some embodiments, the fluid is introduced into the molten metal, wherein the molten metal has a lower viscosity than the molten metal oxide and thus causes a reduced bubble diameter to be formed from the injected fluid. In some embodiments, the fluid is introduced at an angle of less than 90 degrees to a line tangent to each injector relative to a cross section perpendicular to the internal axis of the shell or multiple walls. In some embodiments, the introduction of the fluid causes the fluid to stir the molten metal oxide in the furnace to produce a uniform slag composition and enhance the separation of the metal particles contained in the slag, so that the metal particles gather in the metal layer below the slag layer. In some embodiments, the introduction of the fluid causes the molten metal oxide to swirl in the furnace. In some embodiments, the plurality of injectors are equally spaced around the circumference or a plurality of walls of the shell. In some embodiments, the fluid comprises hydrogen and / or carbon. In some embodiments, the method comprises generating an arc between the distal end of at least one electrode extending from the furnace top toward the furnace bottom and at least one counter electrode at the furnace bottom, wherein the arc is configured to provide thermal energy to the molten bath. In some embodiments, the arc is between the distal end of the at least one electrode and the molten metal oxide and / or molten metal of the furnace. In some embodiments, the method comprises introducing a fluid into the furnace through a port running through the central axis of the at least one electrode. In some embodiments, the method comprises generating plasma from the introduced fluid and the arc. In some embodiments, the arc stirs the molten metal oxide and / or molten metal. In some embodiments, the method comprises introducing more molten metal oxide into the furnace through a feed port closer to the center of the furnace top than a feed port farther from the center of the furnace top. In some embodiments, the molten metal oxide comprises iron ore. In some embodiments, the molten metal oxide comprises iron oxide, hematite, magnetite, a waste stream containing iron oxide, or a combination thereof. In some embodiments, the molten metal comprises metallic iron. In some embodiments, the method includes introducing a carbon source into the furnace through the multiple feed ports and / or through the multiple injectors. In some embodiments, the carbon source is a solid carbon source for carburizing metallic iron. In some embodiments, any fluid injected into the slag layer will partially escape without reducing the molten metal oxide. In some embodiments, the fluid escaping from the molten metal oxide generates plasma around the arc. In some embodiments, the ionized fluid around the arc is sucked into the molten metal oxide by the arc momentum.In some embodiments, the ionized fluid reduces the molten metal oxide near the arc. In some embodiments, the ionized fluid around the arc becomes non-ionized, thereby promoting heat generation in the furnace in an exothermic manner. In some embodiments, the furnace is a DC or AC arc furnace. In some embodiments, the method is operated in batch, continuous or semi-continuous mode.

[0019] It should be understood that any variation, aspect, feature and option described for a furnace is also applicable to the system, method, other furnaces, and vice versa. It should also be clear that any one or more of the above variations, aspects, features and options can be combined.

[0020] Other advantages will be apparent to those skilled in the art from the following detailed description.The aspects and descriptions herein are to be considered illustrative rather than restrictive.

[0021] All publications cited in this application, including patent documents, scientific papers, and databases, are incorporated by reference in their entirety for all purposes to the same extent as if each individual publication was individually incorporated by reference. If definitions set forth herein are contrary to or inconsistent with definitions set forth in patents, applications, published applications, and other publications incorporated herein by reference, the definitions set forth herein take precedence over the definitions incorporated herein by reference. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] The present invention will now be described, by way of example only, with reference to the accompanying drawings, in which:

[0023] Figure 1 An exemplary steelmaking process according to some embodiments herein is illustrated.

[0024] Figure 2 Another exemplary steelmaking process according to some embodiments herein is illustrated.

[0025] Figure 3 An example of a cross section of half of a furnace according to some embodiments herein is illustrated.

[0026] Figure 4 Illustrated is fluid flow in one example of a cross section of half of a furnace according to some embodiments herein.

[0027] Figure 5 Illustrated is a radial fluid jet from a top view of a furnace according to some embodiments herein.

[0028] Figure 6 Angled fluid jets are illustrated from a top view of a furnace according to some embodiments herein.

[0029] Fig. 7AIllustrated is a top view of an exemplary region of a metal oxide feed according to some embodiments herein.

[0030] Figure 7B Illustrated are cross-sections of exemplary regions of a metal oxide feed, a metal layer, a slag layer, and a feed pile, according to some embodiments herein.

[0031] Fig. 8A A diagram illustrating components of a slag layer according to some embodiments herein.

[0032] Figure 8B An enlarged view of the components of a slag layer according to some embodiments herein is illustrated.

[0033] Fig. 9A Illustrated is a portion of a cross-section of an exemplary housing of a furnace according to some embodiments herein.

[0034] Fig. 9B Illustrated is a larger portion of a cross-section of an exemplary furnace having a housing according to some embodiments herein.

[0035] Fig. 10A Illustrated is a top view of an exemplary furnace design according to some embodiments herein.

[0036] Fig. 10B Illustrated is a cross section of an exemplary furnace design according to some embodiments herein.

[0037] Fig.11 An exemplary layout of electrodes from the perspective of a furnace roof according to some embodiments herein is illustrated.

[0038] Fig. 12A An exemplary hydrogen utilization flow diagram according to some embodiments herein is illustrated.

[0039] Fig. 12B An exemplary graph of hydrogen utilization relative to weight percent of FeO in slag according to some embodiments herein is illustrated.

[0040] Fig. 12C An exemplary graph of hydrogen flow rate relative to weight percent of FeO in slag is illustrated according to some embodiments herein.

[0041] Fig.12D Another exemplary hydrogen flow rate chart according to some embodiments herein is illustrated.

[0042] Fig.13A Another exemplary steelmaking process according to some embodiments herein is illustrated.

[0043] Fig. 13BAnother exemplary steelmaking process according to some embodiments herein is illustrated.

[0044] Fig. 13C Another exemplary steelmaking process according to some embodiments herein is illustrated.

[0045] In the drawings, like reference numerals refer to like components unless context dictates otherwise. DETAILED DESCRIPTION

[0046] Reference will now be made in detail to implementations and embodiments of various aspects and variations of the furnaces, systems, and methods described herein. Although 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 combined in any suitable manner, with combinations of all or some of the described aspects. For example, variations of the systems and methods may be applied to convert feed or slag containing molten metal oxides into refined metal.

[0047] The BF-BOF process for producing steel is a four-step energy-intensive process. The process may include converting coal into coke through a coking plant, sintering or pelletizing fine iron ore or lump iron ore in a separate step, reducing the iron ore to carburized 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 heating iron oxide to a temperature above the melting point of iron using coke and converting iron oxide to metallic iron using coke as a reducing agent. Alternative processes, such as direct reduced iron (DRI) in an electric arc furnace (EAF), use natural gas and / or hydrogen as a reducing gas, which can significantly reduce carbon emissions compared to blast furnaces. However, DRI-EAF is a three- to four-step process in which high-grade iron ore is first pelletized, the iron ore is reduced in a DRI process, and the reduced iron is melted in an EAF or the reduced iron is melted and purified in a submerged arc furnace and then refined in an EAF. When the DRI process uses only hydrogen, additional heat input may be required due to the overall endothermic properties of the molecular hydrogen reaction. Currently, a 5% hydrogen mixture can be composed of natural gas or other carbon-containing gases to offset the energy requirements of the endothermic reaction in the DRI process. In addition, because EAF has historically relied on the carbon contained in iron (called pig iron), DRI-EAF may still require carbon input to maintain the temperature of the downstream EAF through the carbon-oxygen exothermic reaction. Hydrogen plasma smelting reduction (HPSR) reaction and / or molecular hydrogen reduction reaction can improve both processes by reducing iron ore and contributing to heat generation by utilizing the ionized state of hydrogen. Hydrogen ions have a greater reduction potential and can reduce iron ore to molten iron and steel in a single step. HPSR can also be an overall exothermic reaction, and the thermal energy generated by the ionized gas can be utilized and recovered. Therefore, compared with BF-BOF and DRI-EAF processes, HPSR and / or molecular hydrogen reduction reactions can reduce capital costs, operating costs and carbon emissions. In combination with the methods disclosed herein for reducing iron oxide in a slag layer with molecular hydrogen, HPSR and / or molecular hydrogen reduction processes may be scalable and economically viable.

[0048] Disclosed herein are systems, methods, and furnaces for molten metal production. The furnace described herein is capable of running HPSR reactions and / or molecular hydrogen reduction reactions. Compared to the most advanced HPSR systems and compared to the hydrogen DRI process, the furnace described herein can improve the reduction kinetics and overall hydrogen utilization in HPSR and / or molecular hydrogen reduction through various hydrogen injection modes. The pattern of hydrogen injection in the furnace described herein can improve the surface area on which the HPSR reaction and / or molecular hydrogen reduction reaction is run. The systems, methods, and furnaces described herein can recycle heat and exhaust gases to improve energy efficiency and reduce operating costs. In addition, the systems, methods, and furnace components described herein can be compatible with commercial steelmaking furnaces to accelerate technology adoption.

[0049] A furnace that can be used for molten metal production is disclosed herein. The furnace may have a wall (e.g., a side wall) and / or one or more shells, and the wall and / or shell may have a top portion and a bottom portion. The top portion may include a furnace roof, and the bottom portion may include a furnace bed, and a wall, one or more shells, or a combination of the two may connect the furnace roof and the furnace bed. The shell or wall may include a plurality of injectors. In some embodiments, the injector may be configured to inject a fluid into the furnace. In some embodiments, the fluid may be molecular hydrogen. In some embodiments, the furnace may be used to perform HPSR and / or molecular hydrogen reduction reactions, in which case hydrogen (e.g., molecular hydrogen) may be heated. The furnace may supply energy to hydrogen so that it is ionized to act as a reducing agent. In some embodiments, the injector may inject hydrogen without preheating hydrogen, in which case the electrodes in the furnace may heat hydrogen, and if necessary, the feed may be melted or the feed may be kept in a molten state. In some embodiments, the injector may preheat hydrogen so that the furnace may alternatively mainly heat iron ore or metal oxides, which may reduce the heat load on the furnace and may improve energy efficiency.

[0050] In some embodiments, at least one electrode may be attached to the furnace roof. The furnace roof may also have multiple feed ports, and iron ore or metal oxides may be fed into the furnace from these feed ports. The electrode may be used to heat the reducing gas or melt the iron ore or metal oxides fed into the furnace. In some embodiments, the furnace bed may be attached with a counter electrode. In some embodiments, the electrode is used to initiate an arc between the electrode and the feed or counter electrode. In some embodiments, the temperature around the arc may be higher than 3,000 degrees Celsius. In some embodiments, the electrode is immersed, in which case ionized hydrogen will not be formed. On the contrary, the injected molecular hydrogen can undergo a reduction reaction. In some embodiments, the furnace roof may be attached with multiple electrodes at a distance from each other, so that the formed arcs merge toward the center of the furnace roof. In some embodiments, the distance between the electrodes makes the behavior of the arcs independent of each other.

[0051] In some embodiments, the hearth may contain a molten bath. The molten bath may include a slag layer that may contain molten metal oxides and a metal layer that may contain molten metal. In some embodiments, HPSR and / or molecular hydrogen reduction reactions may occur in the slag layer. In some embodiments, the slag layer may be foamy. In some embodiments, the slag may be located above the metal layer, and as the metal oxides in the slag are reduced to molten metal, the metal may 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 in the accumulated metal oxides located above the slag or molten bath.

[0052] In some embodiments, the furnace can be configured to melt the metal oxide 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 its molten state. In some embodiments, the furnace can be configured to melt the metal oxide, maintain the metal layer and the slag layer in a molten phase, supply thermal energy to the furnace, supply ionized gas to the molten bath, and / or reduce the metal oxide. Figure 3 An example of a cross section of half of a furnace 300 disclosed herein is illustrated. In some embodiments, the furnace can have a variety of shapes and sizes. For example, the furnace can be spherical, cylindrical, square, rectangular, etc. For example, Figure 3-4 A cylindrical shaped furnace is illustrated, while a rectangular shaped furnace is illustrated in Figure 10. In some embodiments, the furnace may have a diameter D of about 1-100 meters, about 1-50 meters, about 1-25 meters, about 5-25 meters, about 10-20 meters, or about 15 meters.

[0053] In some embodiments, the furnace may include a furnace roof or top 301. The furnace 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 component for making steel. In some embodiments, the metal oxide is iron ore. In some embodiments, the iron ore may be in the form of fines, blocks and / or pellets. In some embodiments, the metal oxide may include iron oxide, hematite, magnetite, waste streams containing iron oxide, or a combination thereof. Examples of waste streams containing iron oxide may be waste generated from ore sand processing, waste generated when ilmunite is converted into synthetic rutile via the Becher process, etc. In some embodiments, the metal oxide may be a pre-reduced metal oxide. In some embodiments, the waste gas from the furnace may be partially composed of reducing gases and may be used to pre-reduced metal oxides. The waste gas may be generated by all gases in the furnace, including hydrogen that does not react with the material in the furnace, water vapor generated due to the reaction of hydrogen with oxygen in the furnace, and gangue elements (e.g., sulfur and phosphorus) evaporated due to the high temperature in the furnace. In some embodiments, the pre-reduction of metal oxides can be carried out in a separate furnace. In some embodiments, the waste gas can be treated to remove water vapor and / or evaporated gangue elements so that most of the hydrogen is retained. The hydrogen can be re-injected into the furnace. In some embodiments, the waste gas can be treated to remove evaporated gangue elements and reduce the temperature. This reduced and treated waste gas can be sent to solid water, sent to a low temperature or high temperature water electrolyzer to regenerate a fluid (e.g., hydrogen).

[0054] 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, whether it is introduced by the feed port or the solid injected into the furnace by one or more injectors (described below) can be used as the nucleation point of bubble nucleation. In some embodiments, the carbon source is injected into the metal bath to carburize the molten metal. In some embodiments, the carbon source can be a gas and introduced by a fluid injector. In some embodiments, the gaseous carbon source can be natural gas / methane.

[0055] In some embodiments, the furnace roof may include a plurality of feed ports 303. The feed ports (boxes or hoppers) may be configured to introduce metal oxides into the furnace for subsequent melting. In some embodiments, the plurality of feed ports may be arranged in a circular or annular manner around the furnace roof, such as Figure 5-6 In some embodiments, the plurality of feed ports may be arranged in a circular or annular manner around the center of the furnace roof. In some embodiments, the plurality of feed ports may be arranged around the periphery of the furnace roof, as shown in Figure 10. In some embodiments, each of the plurality of feed ports may be equidistant from each other. In some embodiments, the number of feed ports may be determined based on the fluid jet impact area described below.

[0056] In some embodiments, the plurality of feed ports may be configured such that a feed port closer to the center of the furnace top may introduce more metal oxide into the furnace than a feed port further from the center of the furnace top. Fig. 7A and 7B An example of zoning the feed ports from the perspective of a cross section or half of a cross section of a cylindrical furnace is illustrated. In some embodiments, the feed ports can be arranged in at least one area around the center of the furnace top in a circular or annular manner. In some embodiments, one or more areas closer to the center of the furnace top can introduce more feed material (e.g., metal oxide) than adjacent areas farther from the center of the furnace top. These feed port areas can be arranged in an annular manner around the center of the furnace top. For example, Fig. 7A and 7BFeed port areas Z1, Z2 and Z3 are illustrated. Z1, which is closer to the center of the furnace top (electrode 310) than Z2 and Z3, can introduce more feed material than Z2 and Z3. For example, the feed port of Z1 closer to the center of the furnace top can introduce 60% of the total feed, the feed port of Z2 farther from the center of the furnace top than Z1 can introduce 30% of the total feed, and the feed port of Z3 farther from the center than Z2 can introduce 10% of the total feed. Therefore, the feed port area farther away from the center of the furnace top can introduce a lower percentage of the total feed than those ports closer to the center of the furnace top. In some embodiments, the situation may be the opposite (that is, the feed port area farther away from the center of the furnace top can introduce a higher percentage of the total feed than those ports closer to the center of the furnace top). In addition, a gas injector, such as a top immersion spray gun, can be placed through the furnace top port.

[0057] In some embodiments, molten metal can be formed by introducing metal oxide into the furnace through multiple feed ports in the furnace top. For example, the furnace can be configured to melt metal oxide feed 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 oxide. In some embodiments, the slag layer can be a byproduct of melting feed material (e.g., iron ore). In some embodiments, the slag layer can include iron materials, ferroalloys and / or non-iron / base metals (e.g., copper, nickel, zinc, phosphorus, etc.). In some embodiments, the slag layer can include a fluid that can reduce molten metal oxide. In some embodiments, the metal layer can include molten metal. In some embodiments, the slag layer can be a byproduct produced during the separation of molten metal from impurities in the molten metal manufacturing process. In some embodiments, the molten metal can include metallic iron that can be used for steel. In some embodiments, there is only a slag layer without the separation of the metal layer and the slag layer.

[0058] In some embodiments, components in the slag layer (e.g., molten metal oxides) can be reduced to form molten metal in the metal layer. The metal layer can have a greater density than the slag layer, so that the metal layer will sink to the bottom of the furnace while the slag layer is above it. For example, Figure 8B The fluid or fluid bubbles 313 (e.g., hydrogen) in the slag layer 307 are illustrated reducing metal oxides (e.g., iron oxide) 320 in the slag layer to form metal 321 (e.g., metallic iron), which has a greater density than the metal oxide and sinks or settles toward the bottom of the furnace. Depending on the density and viscosity of the slag layer, agitation in the slag layer, and bath mixing, some of the metal may remain as droplets in the slag layer. Above the slag layer may be unreacted fluids (as described below), product gases (e.g., water vapor), and / or evaporated gangue elements (e.g., sulfur and / or phosphorus) from the reduction process.

[0059] In some embodiments, the furnace may include a shell, a wall or multiple walls (e.g., side walls) 302. The shell may serve as one or more side walls or one or more walls of the furnace. In some embodiments, the shell may include multiple walls. In some embodiments, the shell may be cylindrical, square, rectangular, spherical, etc. In some embodiments, the shell may include a top portion and a bottom portion. In some embodiments, the furnace top may be connected to the top portion of the shell to close the top of the furnace / shell. In some embodiments, the furnace top and the shell may be integrally connected / combined to form a single unit. In some embodiments, the furnace may include a furnace bed 309 toward the furnace bottom. In some embodiments, the furnace bed may be connected to the bottom portion of the shell to close the bottom of the furnace / shell. In some embodiments, the furnace bed and the shell may be integrally connected / combined to form a single unit. In some embodiments, the furnace top, the shell, and the furnace bed may be integrally connected / combined to form a single unit. In some embodiments, the wall or one or more shells of the furnace may include a feed port.

[0060] 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 material (e.g., metal oxide) and / or the material (e.g., molten metal oxide) in the slag layer. The injector can be configured to inject fluid into the furnace so that there is enough residence time with the metal oxide in the slag layer to reduce it to metal. In some embodiments, the fluid can reduce the molten metal oxide in the slag layer to molten metal, which can be settled in the metal layer below the slag layer. In some embodiments, the fluid can reduce the metal oxide to metal (e.g., metallic iron) before melting. In some embodiments, the fluid can also reduce ilmenite, copper oxide and / or any other metal oxide or ore in the furnace or slag layer. In some embodiments, the fluid can be a reducing gas. In some embodiments, the reducing gas is hydrogen (e.g., molecular hydrogen), atomic hydrogen, ionized hydrogen, methane, natural gas, ammonia and / or any other hydrogen-containing fluid or gas.

[0061] In some embodiments, at least one of the multiple injectors is configured to inject fluid into the furnace so that the fluid can stir the molten bath, slag layer and / or metal layer in the furnace. In some embodiments, a fluid can be introduced into the furnace so that it stirs the molten bath to produce a uniform slag composition and / or enhances the separation of the molten metal contained in the slag so that the molten metal can gather / sediment in the metal layer below the slag layer. In some embodiments, at least one of the multiple injectors can be configured to inject fluid into the furnace so that the slag layer and / or metal layer of the fluid-induced molten bath are mixed. Such mixing and / or stirring 312 can increase the gas-solid and / or gas-liquid reduction reaction rate in the furnace. In some embodiments, the multiple injectors can be configured to inject fluid so that the fluid can penetrate the molten bath (e.g., slag layer and / or metal layer).

[0062] In some embodiments, at least one of the plurality of injectors is configured to inject fluid radially inwardly into the furnace, such as Figure 5 In some embodiments, at least one of the plurality of injectors is configured to inject fluid toward the hearth, such as Figure 3-4 In some embodiments, at least one of the plurality of injectors is configured to spray fluid toward the molten bath in the furnace. In some embodiments, at least one of the plurality of injectors is configured to spray fluid toward the working area of ​​the furnace. In some embodiments, the working area may be where the molten bath and / or slag layer (e.g., molten metal oxide) in the furnace is located. In some embodiments, at least one of the plurality of injectors may be configured to spray fluid into the molten bath of the furnace. In some embodiments, at least one of the plurality of injectors may be configured to spray fluid into the slag layer and / or metal layer of the molten bath in the furnace. In some embodiments, the injector may be immersed in the molten bath. In some embodiments, the injector may be located above the molten bath.

[0063] In some embodiments, the fluid injected into the molten bath (e.g., slag layer and / or metal layer) can cause the fluid to flow according to the buoyancy effect (the fluid density may be less than the molten bath density, slag density or metal density) and transfer momentum from the injected fluid to the molten bath. In some embodiments, because the injected fluid can be decomposed into bubbles 313 in the molten bath, momentum transfer of the injected fluid to the molten bath can also occur. Therefore, buoyancy and / or mixing from the injected fluid can increase the reduction reaction rate in the furnace. In some embodiments, the fluid injected into the furnace can be sheared in the molten bath (e.g., slag layer and / or metal layer) to produce discrete volumes of gas, which can be 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 may not be spherical. The amount, volume and shape of the discrete volumes of gas can vary based on the angle and direction of shear caused by the fluid injector.

[0064] In some embodiments, at least one of the plurality of injectors may 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 plurality of injectors may be 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, such that the fluid may reach / interact with a different region of the molten bath. In some embodiments, each of the plurality of injectors is configured to inject fluid toward and / or into a different region of the molten bath.

[0065] In some embodiments, at least one of the plurality of injectors may be configured to inject the fluid in a direction toward an adjacent injector. In some embodiments, the plurality of injectors may be configured to inject the fluid so that the slag layer and / or metal layer of the molten bath swirls within the furnace to increase mixing and / or agitation of the molten bath and the fluid (and thus increase the reduction reaction rate). In some embodiments, the shell of the furnace may have Figure 7B An internal axis A extending longitudinally through the center of the shell (and furnace) is shown in FIG. In some embodiments, at least some of the plurality of injectors may be configured to inject fluid at an angle of less than 90 degrees relative to a line tangent to each injector in a cross section of the shell perpendicular to the internal axis. For example, Figure 6 A cross section of the housing perpendicular to the inner axis is shown. Figure 6 In some embodiments, the injectors are configured to inject fluid at an angle 317 less than 90 degrees (e.g., 10-45 degrees, 10-30 degrees, 20-30 degrees, or 20-25 degrees) relative to a line 316 of the cross section that is tangential to each injector 304. Angling such injectors can create a swirling effect 318 of the molten bath (e.g., a slag layer and / or a metal layer). In some embodiments, the plurality of injectors can be equally spaced around the circumference of the shell. In some embodiments, the plurality of injectors can be equally spaced around the periphery of the shell.

[0066] In some embodiments, at least one of the plurality of injectors may be immersed in the molten bath. In some embodiments, at least one of the plurality of injectors may be immersed in the slag layer and / or metal layer of the molten bath. In some embodiments, at least one of the plurality of injectors may be immersed in the molten bath between the slag layer and the metal layer. In some embodiments, the immersed one or more injectors may contact both the slag layer and the metal layer of the molten bath. In some embodiments, the plurality of injectors may include injectors immersed in the molten bath and injectors that are not immersed (e.g., above the molten bath).

[0067] In some embodiments, the furnace roof may also include at least one injector configured to inject fluid into the furnace. In some embodiments, the furnace roof may include multiple injectors configured to inject fluid vertically into the furnace. In some embodiments, multiple injectors in the furnace roof may be configured to inject fluid at an angle of 90 degrees relative to the furnace roof so that it is perpendicular to the molten bath (e.g., the slag layer of the molten bath).

[0068] In some embodiments, a plurality of injectors disclosed herein may include a spray gun, a supersonic jet, a coherent jet, a plasma torch or a jet, an injector configured to eject both gas and solid, or a combination thereof. In some embodiments, the plasma torch may be a non-thermal plasma torch. In some embodiments, the coherent jet may include a supersonic coherent jet, a subsonic coherent jet, and / or a coherent jet with a shrouded flame. In some embodiments, the fluid may be preheated before being ejected into the furnace so that the thermal energy in the furnace is not wasted on heating the fluid. In some embodiments, the plasma torch may electrically heat the fluid before ejecting it into the furnace so that the fluid may contribute to the thermal energy supplied to the furnace and / or the molten bath (if it is hotter than the molten bath), or if it is the same temperature as the molten bath, any energy of the furnace will not be wasted on heating the fluid.

[0069] In some embodiments, the housing can include at least one heat exchanger 322. In some embodiments, the at least one heat exchanger can be used to protect the housing itself from melting due to the heat used in the furnace. In some embodiments, the housing can include multiple heat exchangers to cool the housing. In some embodiments, the at least one heat exchanger can be a heat exchanger that is cooled using water passing through the interior of the housing. In some embodiments, the housing can be formed from multiple housing segments, such as Fig. 9B As shown in . In some embodiments, the interior of the shell may include multiple notches, intervals or openings 325, where the slag can solidify 323, thereby forming a protective layer on the interior of the shell. In some embodiments, the shell may be made of copper. In some embodiments, the shell may include at least one copper cooler. In some embodiments, the furnace roof may also be made of copper and / or may include at least one copper cooler. The copper cooler may have at least one heat exchanger (e.g., water cooling) in the wall of the cooler. In some embodiments, the interior of the furnace (e.g., the shell, the furnace roof and / or the furnace bed) may be lined with a castable refractory lining 324. Arc radiation and radiation from the molten pool may require refractory materials to line the furnace wall. The purpose of the refractory lining may be to enhance the integrity of the furnace by protecting the wall from molten metal and slag splashing, strong heat in the furnace and / or radiation. In addition, the lining will reduce 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.

[0070] In some embodiments, the multiple feed ports and / or the 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 plastics, coal, coke or biochar. In some embodiments, carbon can be injected into the furnace and the molten bath so that the desired amount of carbon can be present in the molten bath to form the desired product (e.g., 2% carbon in iron for steel production). In some embodiments, the reduction of metal oxides can be performed without adding carbon. In some embodiments, the solid injected into the furnace by one or more injectors (described below) can be used as a nucleation point for bubble nucleation. In some embodiments, solids can be injected simultaneously and / or in combination with fluids in the same or different injectors. Solids can be used as bubble nucleation points for injecting fluids to increase the reaction surface area between fluids and feed materials (e.g., metal oxides).

[0071] In some embodiments, the furnace may include at least one heating source. In some embodiments, the furnace top may include at least one electrode 310 (e.g., cathode) extending from the furnace top toward the furnace bed. In some embodiments, the furnace bed may include at least one counter electrode 326 (e.g., anode) relative to the at least one electrode. In some embodiments, the at least one counter electrode may be embedded in the furnace bed. The furnace may be configured to generate an arc 311 between the distal end of the at least one electrode and the at least one counter electrode. In some embodiments, under AC or DC operation, at any given time, the at least one electrode is a cathode and the at least one counter electrode is an anode. The arc may be configured to melt feed material (e.g., metal oxide) to form a molten bath. In some embodiments, the at least one electrode may be located in the middle of the furnace. In other words, the at least one electrode may be on the internal axis A of the furnace.

[0072] In some embodiments, the arc may be between the distal end of the at least one electrode and the molten bath of the furnace. In some embodiments, the distal end of the at least one electrode may be above the molten bath or the slag layer of the molten bath. In some embodiments, the distal end of the at least one electrode may be immersed in the molten bath (e.g., in the slag layer and / or the metal layer). In some embodiments, the arc may be a transferred or non-transferred arc. In embodiments in which a transferred arc is employed, the molten bath may be part of an electrical circuit. The arc may be established between the electrode and the molten bath, and the electrode and the molten bath may not be in direct physical contact with each other. Ionized gases may be generated in and around the arc and may be in contact with the molten bath. In embodiments in which a non-transferred arc is employed, the arc may not interact with the molten bath. Alternatively, a plasma torch, for example, may be used, in which the arc may be generated between the electrode and the nozzle of the plasma torch. Ionized gases may be generated within the plasma torch and the hot gases exit to the torch at high temperature and high speed. The transferred arc configuration may have an electrothermal efficiency of 20% higher than that of the non-transferred arc technology.

[0073] In some embodiments, the arc can cause a flow pattern in the molten bath (e.g., the slag layer and / or the metal layer). In some embodiments, the momentum 314 of the arc can force a portion of the molten bath (e.g., a portion of the slag layer and / or the metal layer) away from the arc to form a depression 327 in the molten layer (e.g., in the slag layer and / or the metal layer), such as Figure 7B and 10B . In some embodiments, fluids and materials (e.g., metal oxides) around the arc can be pulled toward the arc. In some embodiments, the flow pattern attributed to the arc can be a reverse flow of the buoyancy effect of the fluid injected into the molten bath. Therefore, both the arc and the fluid injection can cause agitation / mixing of the molten bath, thereby increasing the reaction rate of reduction of materials in the molten bath. In some embodiments, a flow pattern 315 can exist in the metal layer due to shear forces between the metal layer and the slag layer.

[0074] In some embodiments, the at least one electrode can be hollow. Therefore, the at least one electrode can include a port that runs through the central axis of the at least one electrode. In some embodiments, the port can be used to inject fluid and / or feed material. In some embodiments, the at least one electrode can be solid (that is, not hollow). In such an embodiment, the fluid can be injected only through a plurality of injectors in the shell and / or the furnace roof, without being injected by the at least one electrode.

[0075] In some embodiments, at least a portion of the fluid injected into the furnace can pass through the arc to form plasma. In some embodiments, the fluid can be injected into the molten bath, and some fluids may escape the molten bath without reducing the metal oxides in the slag layer. In some embodiments, the fluid escaping the molten bath can generate plasma around the arc. In some embodiments, plasma can be formed around the arc. In some embodiments, plasma can surround the arc. The fluid passing through the arc can become an ionized fluid. For example, the hydrogen passing through the arc can become ionized hydrogen. In some embodiments, ionized fluids and / or plasmas can exist around the arc and / or be pulled into the molten bath. In some embodiments, plasma can melt feed materials (e.g., metal oxides) and / or can supply heat energy to the furnace. In some embodiments, plasma can also reduce feed materials (e.g., metal oxides) or melt feed materials (e.g., molten metal oxides). In some embodiments, the ionized fluid around the arc can be sucked into the molten bath (e.g., slag layer and / or metal layer) due to the momentum of the arc. In some embodiments, the ionized fluid can reduce metal oxides in the slag layer near the arc. In some embodiments, the ionized fluid can become non-ionized, which can exothermically promote heat generation in the furnace. For example, ionized hydrogen around the arc can recombine into atomic hydrogen or molecular hydrogen, thereby exothermically promoting heat generation in the furnace.

[0076] 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 components of the furnace can be compatible with an AC or DC electric arc furnace, such that an AC or DC electric arc furnace can be retrofitted with any of the components described herein.

[0077] In some embodiments, at least one of the plurality of injectors can be configured to inject fluid toward and / or into the arc. In some embodiments, at least one of the plurality of injectors in the furnace roof can be configured so that the plurality of injectors can be closer to the center of the furnace roof and / or the at least one electrode. In some embodiments, the electrodes can be spaced apart by E( Fig.11 ) about 1-20 meters, about 1-15 meters, about 1-10 meters or about 5-8 meters.

[0078] In some embodiments, the furnace roof may include a plurality of electrodes (eg, cathodes) extending from the furnace roof toward the hearth, such as Fig. 10A , 10B and 11. The configuration of the electrodes may depend on the shape of the furnace. For example, Fig. 10A and 10B shows electrodes spaced apart along a rectangular furnace, and Fig.11Electrodes spaced apart in a cylindrical furnace are depicted. In some embodiments, the furnace can be configured to generate an arc between a distal end of each of the plurality of electrodes and at least one counter electrode (e.g., one or more anodes). In some embodiments, the distances between the plurality of electrodes are such that there may not be any arc interference between the arcs 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 may be made of carbon, graphite, titanium, tungsten, tantalum, zirconium, copper, or a combination thereof.

[0079] Figure 1 An exemplary steelmaking process according to some embodiments of the present invention is illustrated. Figure 1 As shown in , iron ore or metal oxides can be introduced into dryer 101 to remove excess water. The iron ore or metal oxides can enter the dryer directly, or they can be first mixed with iron ore dust collected by cyclone separator system 107 and processed by scrubber 108. Scrubber 108 can release ore and hydrogen from water vapor, harmful minerals or gases. Harmful substances can include gangue elements or oxides. Gangue can include SiO2, CaO, MgO and Al2O3. Gangue and other impurities can leave through impurity discharge port (bleed) 114. After leaving the scrubber, the washed material 112 can be separated into solid and liquid components, and the solid component of the washed material (such as iron ore dust) can enter dryer 101. Dryer 101 can mix high-grade iron ore with the solid component of the washed material, and an additional heat exchanger or auxiliary step 113 can be optionally performed before the solid enters the dryer. The treated and dried iron ore can be introduced into the pre-reduction chamber 102 to generate pre-reduced iron. For example, the pre-reduction chamber 102 can be a fluidized bed, a reduction shaft furnace, a cyclone converter, a spouting reactor, a countercurrent shaft furnace or any gas-solid reactor. In some embodiments, the pre-reduction chamber 102 may include other equipment from a conventional blast furnace or equipment used in a direct reduced iron (DRI) process, such as a bubbling fluidized bed reactor for reducing fine iron ore or a shaft furnace for pelletizing iron ore. In other embodiments, the pre-reducer may be included in the main furnace. In this embodiment, the furnace may have two compartments, an upper compartment, in which the exhaust gas flows upward away from the arc and passes through the shaft above the furnace, while the iron ore falls through the compartment to the bottom compartment of the furnace, where smelting occurs and the final reduction stage of FeO to metallic Fe occurs. In some embodiments, the two compartments are directly connected. In other embodiments, there is a heat exchanger between the two compartments to reduce the temperature of the exhaust gas before pre-reducing the metal oxide.

[0080] Hydrogen can act as a reducing gas, wherein a hydrogen supplier 111 can supply hydrogen / molecular hydrogen to the pre-reduction chamber 102 and the main furnace 103. The main furnace 103 can be any furnace embodiment described herein. Hydrogen / molecular hydrogen can be compressed by a compressor 109. Compressed hydrogen can enter the pre-reduction chamber 102 and the main furnace 103 together with the dried iron ore or metal oxide. In the pre-reduction chamber, hydrogen can pre-reduce the iron ore or metal oxide. In some embodiments, pre-reduction can be performed by a blast furnace process or a DRI process. In the main furnace 103, the pre-reduced iron ore or metal oxide or the iron ore or metal oxide from the dryer 101 can be reduced in a hydrogen plasma smelting reaction (HPSR) and / or a molecular hydrogen reduction reaction. Due to the exothermic compound reaction between ionized hydrogen, the HPSR can be an overall exothermic reaction, and the metal oxide can be reduced with a lower heat demand than a reaction that relies only on molecular hydrogen.

[0081] The reduction products from the main furnace 103 may be liquid iron / metal, matte, slag, or steel. The reduction products may be transferred to a ladle 105. The ladle 105 may be a furnace that may refine liquid iron / metal or steel. The slag produced by the HPSR and / or molecular hydrogen reduction in the main furnace 103 may enter a slag granulation system 104. The slag granulation system 104 may atomize the slag to release heat energy, which may be recycled back to the dryer 101 to reduce energy consumption.

[0082] To further improve energy efficiency, residual materials can be recovered from pre-reduction and HPSR and / or molecular hydrogen reduction. Residual materials may include solids such as unreacted iron ore / metal oxides as well as waste gases, gangue elements or water vapor. The waste gases may leave the main furnace 103 or the pre-reduction chamber 102, where they may pass through the recuperator 106. The recuperator 106 may perform countercurrent heat exchange and recover heat energy from the waste gases. After the waste gases leave the recuperator 106, a cyclone separator 107 may be used to separate residual iron ore / metal oxide dust from the waste gases. The residual iron ore / metal oxides may then re-enter the pre-reduction chamber 102.

[0083] The off-gas may leave the cyclone 107 and enter the scrubber 108, where hydrogen and other gases may be separated from the gangue elements. After leaving the scrubber, the gas may re-enter the compressor to be used again in another reduction reaction. There may be a fan 115, which may facilitate the flow of scrubbed gas and hydrogen to the compressor. In addition, there may be a gas outlet 110, which may separate the non-condensable off-gas from the hydrogen so that the non-condensable gases do not enter the main smelting reduction furnace 103. These non-condensable gases may include nitrogen, carbon dioxide, carbon monoxide, or a combination thereof.

[0084] Figure 2Another exemplary steelmaking process according to some embodiments of the present invention is illustrated. Figure 2 As shown in , the iron ore or metal oxide may be first 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 generate pre-reduced iron. For example, the pre-reduction chamber 202 may be a fluidized bed (including a bubbling fluidized bed or a circulating fluidized bed), a reduction shaft furnace, a cyclone converter, a spouted 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 reduced iron (DRI) process.

[0085] Hydrogen can be introduced into the pre-reduction chamber 202 from a hydrogen supplier 211. The hydrogen supplier 211 can also introduce hydrogen for injection into the main furnace 203. The main furnace 203 can include any furnace embodiment described herein. In some embodiments, the hydrogen introduced by the hydrogen supplier can enter the pre-reduction chamber 202 or the main furnace 203 without being compressed by the compressor 209.

[0086] In the main furnace 203, the pre-reduced iron ore or metal oxide can be reduced by injected hydrogen via HPSR and / or molecular hydrogen reduction reaction. HPSR can be 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 reduction product can be transferred to the ladle 205. The ladle 205 can be a furnace that can refine liquid iron / metal or steel. The main furnace 203 can also produce slag 204 and may or may not recover heat from the slag 204.

[0087] To further improve energy efficiency, residual materials can be recovered from pre-reduction and HPSR and / or molecular hydrogen reduction. Residual materials may include solids such as unreacted iron ore / metal oxides and waste gases, including unreacted hydrogen, gangue elements or water vapor. The waste gases may leave the main furnace 203, where they may pass through a recuperator 206 that may perform countercurrent heat exchange and recover heat energy from the waste gases. A fan 212 may facilitate the circulation of the waste gases through the recuperator 206. Hydrogen may leave the recuperator 206 and may be pressurized and heated before being recycled into the pre-reduction chamber 202.

[0088] The waste gas and residual solids can leave the pre-reduction chamber 202 and can enter the cyclone separator 207. The cyclone separator 207 can be used to separate the residual iron ore / metal oxide from the waste gas and recycle the residual iron ore / metal oxide and the waste gas. Then, the residual iron ore / metal oxide can re-enter the pre-reduction chamber 202. The waste gas can leave the cyclone separator 207 and can enter the scrubber 208. The scrubber 208 can separate hydrogen from non-condensable gases. These non-condensable gases can include nitrogen and carbon dioxide. The non-condensable gases can leave through the gas outlet 210, and the recovered hydrogen can enter the compressor 209 before being injected into the main furnace 203.

[0089] In another embodiment, the high temperature water vapor leaving the reactor or pre-reduction chamber can be directed to a steam electrolyzer (also known as a solid oxide electrolyzer (SOEC)) to further produce hydrogen. Before the SOEC, the gangue elements can be scrubbed from the exhaust gas to avoid poisoning of the SOEC. The hydrogen produced by the SOEC is then directed back to the reactor for metal oxide reduction.

[0090] Fig. 12A An exemplary hydrogen utilization flow chart according to some embodiments of the present invention is illustrated, and Fig. 12B -D illustrates an exemplary hydrogen utilization and flow rate diagram associated with the hydrogen utilization flow diagram. More specifically, Fig. 12A An example iron production characteristic of 200,000 metric tons per year in a single electrode furnace without an optimized process and without a gas preheater is illustrated. An 80MW electric arc furnace, hydrogen, and steam from a prereduction furnace can be sent to the main electric arc furnace (EAF). In the prereduction in front of the furnace, the iron ore can be partially metallized to iron. H2 gas can be heated in the EAF. The gas used for prereduction can enter at about 800-1000°C (~900°C) and leave at about 200-400°C (~300°C). Solids (e.g., iron ore) in the prereduction stage can enter at about 20-30°C (~25°C) and leave at about 600-800°C (~700°C). The EAF can heat the solids from 700°C to about 1600-1700°C (~1625°C).

[0091] In some embodiments, the methods described herein can be applied to batch, continuous or semi-continuous production of metals from metal oxides. Fig. 12B, a high weight percentage of metal oxides is maintained in the slag to improve the hydrogen utilization of the process. The metal layer below the slag can be discharged continuously or in batches. Once a critical volume of slag with a high metal oxide content is produced, an increased volume of a reducing agent (e.g., hydrogen) can be injected into the slag to convert the remaining oxides in the slag into metals. The slag can then be discharged and the cycle can be started again, with a high weight percentage of metal oxides maintained in the slag for most of the operation.

[0092] In some embodiments, there are at least two furnaces described herein that are connected. In the first furnace, a slag with a high metal oxide content can be kept above the metal layer to maximize hydrogen utilization during operation. The slag from the first furnace can then be transferred to the second furnace, where a reducing agent can be sprayed into the slag to recover metal (e.g., FeO to Fe) from the metal oxide in the slag. Both furnaces may or may not use electric arcs to produce ionized hydrogen and / or supply heat to the furnace.

[0093] Fig.13A An exemplary steelmaking process according to some embodiments of the present invention is illustrated. Fig.13A As shown in, iron ore or metal oxide in the form of fine material, block, pellet, etc. can be introduced into dryer 1301 to remove excess water. Dryer 1301 can be heated, for example, by a hydrogen fuel burner. For iron ore or metal oxide fine material, dryer 1301 can be a fluidized bed. In some embodiments, dried iron ore or metal oxide can be directly introduced into main furnace 1303. In main furnace 1303, iron ore or metal oxide can be reduced to metal. Unreduced metal and gangue elements or oxides from ore can be discharged from the furnace as slag. The oxide introduced into furnace 1303 can be reduced by hydrogen or hydrogen mixture (e.g., molecular hydrogen, hydrogen plasma, hydrogen-argon mixture, hydrogen-nitrogen mixture), and hydrogen or hydrogen mixture can be preheated by preheater 1304. Before being introduced into furnace 1303 or preheater 1304, hydrogen can be compressed to exceed ambient pressure by compressor 1305. Compressed or uncompressed hydrogen can be introduced into the furnace 1303 through ports around the furnace, lances, or gas injectors, which can introduce hydrogen directly into or above the slag bath. Hydrogen can also or alternatively be introduced through hollow electrodes in the furnace 1303. The hydrogen introduced into the furnace can contact the electric arc in the furnace, thereby generating hydrogen plasma (i.e., ionized hydrogen). The ionized hydrogen can then react with the metal oxide to reduce the metal oxide.

[0094] In order to maximize thermodynamic efficiency and minimize operating costs, heat can be recovered from the main furnace 1303. The exhaust 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 the hydrogen or other reducing gas in the preheater 1304. The lower temperature exhaust gas from the recuperator 1306 can be introduced into, for example, an electrostatic precipitator 1307. The electrostatic precipitator 1307 can separate the residual metal oxide dust from the exhaust gas, which can then be reintroduced into the dryer 1301 or the furnace 1303. The exhaust gas from the dryer 1301 can be used to heat the electrostatic precipitator 1307. The exhaust gas can then be introduced into a gas scrubber and / or condenser 1308, where the remaining hydrogen can be separated from the water vapor. Other gases present in the exhaust gas, such as SOx or NOx, can be separated from the exhaust gas by the scrubber 1308 in addition or alternatively.

[0095] In another embodiment, scrap metal may be added to the main furnace 1303 in addition to iron ore to produce steel. In yet another embodiment, the iron discharged from the main furnace 1303 is introduced into a ladle furnace where it is refined into steel. In yet another embodiment, carbon is introduced into the main furnace 1304 according to the desired steel alloy composition. The introduced carbon dissolves in the iron bath and steel is discharged from the main furnace 1304.

[0096] Fig. 13B Still another exemplary steelmaking process according to some embodiments is illustrated. Fig. 13B As shown in, the iron ore or metal oxide can first be introduced into the pelletizer 1311 to bond the ore or oxide together to form pellets. The pelletized iron ore or metal oxide can then be introduced into the dryer 1312 to remove moisture, including crystal water. The pelletized and dried iron ore can then be introduced into the pre-reduction chamber 1313 to generate pre-reduced iron oxide. The pre-reduction chamber 1313 can be a vertical furnace, a rotary kiln, or an 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 reduced iron (DRI) process.

[0097] Hydrogen can be introduced into the pre-reduction chamber 1313 from a hydrogen supplier. The hydrogen supplier can additionally or alternatively introduce hydrogen to be injected into the main furnace 1314. The main furnace 1314 can include any furnace embodiment described herein. In some embodiments, the hydrogen introduced by the hydrogen supplier 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.

[0098] In the main furnace 1314, the pre-reduced iron ore or metal oxide can be reduced by injected hydrogen via hydrogen plasma smelting reduction (HPSR) and / or molecular hydrogen reduction reaction. The reduction product from the main furnace 1314 can be liquid iron / metal or steel. The main furnace 1314 can also produce slag, and heat energy may or may not be recovered from the slag.

[0099] To further improve energy efficiency, residual materials can be recovered from pre-reduction and HPSR and / or molecular hydrogen reduction. Residual materials may include solids such as unreacted iron ore / metal oxides and waste gases, including unreacted hydrogen, gangue elements or water vapor. The waste gases may leave the main furnace 1314, where they may pass through a recuperator 1316 that may perform countercurrent heat exchange and / or recover heat energy from the waste gases. Hydrogen may leave the recuperator 1316 and may be recycled to the pre-reduction chamber 1313. The heat energy recovered from the recuperator 1316 may be used to preheat hydrogen from a hydrogen supplier and / or to preheat hydrogen recovered after the pre-reduction chamber 1313.

[0100] The waste gas and residual solids can leave the pre-reduction chamber 1313 and can enter the electrostatic precipitator 1317. The electrostatic precipitator 1317 can be used to separate the residual iron ore / metal oxide from the waste gas and recycle the residual iron ore / metal oxide and the waste gas. Then, the residual iron ore / metal oxide can re-enter the pelletizer 1311. The waste gas can leave the electrostatic precipitator 1317 and can enter the 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. Non-condensable gases can leave through the gas outlet, and the recovered hydrogen can enter the compressor 1315 before being injected into the main furnace 1314.

[0101] Fig. 13C Still another exemplary steelmaking process according to some embodiments herein is illustrated. Fig. 13CAs shown in, iron ore or metal oxide can be introduced into preheater or dryer 1321 to remove excess water and / or preheating materials. Iron ore or metal oxide can enter dryer directly, or in some embodiments it can be first mixed with iron ore dust collected by cyclone separator system 1322 and processed by scrubber / condenser 1331. Scrubber 1331 can release ore and hydrogen from water vapor, harmful minerals or and / or gases. Harmful substances may include but are not limited to gangue elements or oxides, such as SiO2, CaO, MgO and / or Al2O3. Gangue and other impurities can leave through impurity discharge port. Iron ore or metal oxide after recovery cyclone separator 1322 can be introduced into sealed bin 1323, where iron ore or metal oxide fines can be mixed with flux. Then the mixed feed can be introduced into pre-reduction chamber 1324 to generate pre-reduced iron or pre-reduced metal oxide. Small diameter iron ore fines or metal oxide fines can be recovered by cyclone separator 1330 and returned to the pre-reduction chamber 1324. For example, the pre-reduction chamber 1324 can be a fluidized bed, a reduction shaft furnace, a cyclone converter, a spouted bed reactor, a countercurrent shaft furnace or any gas-solid reactor. In some embodiments, the pre-reduction chamber 1324 may include other equipment from a conventional blast furnace or equipment used in a direct reduced iron (DRI) process, such as a bubbling fluidized bed reactor for reducing fine iron ore. In some embodiments, the pre-reduction chamber 1324 may be incorporated into the main furnace 1325. In some embodiments, the main furnace 1325 may have two compartments, such as an upper compartment, in which the exhaust gas flows upward away from the arc and through the shaft above the furnace, and the iron ore falls through the upper compartment to the bottom compartment of the furnace, where smelting can occur and the final reduction stage of FeO to metallic Fe can occur. In some embodiments, the two compartments are directly connected. In other embodiments, there may be a heat exchanger 1328 between the two compartments to reduce the temperature of the exhaust gas, for example, prior to pre-reduction of the metal oxides.

[0102] Hydrogen can act as a reducing gas, wherein a hydrogen supplier can supply hydrogen / molecular hydrogen to the pre-reduction chamber 1324 and the main furnace 1325. The main furnace 1325 can be any furnace embodiment described herein. Hydrogen / molecular hydrogen can be compressed by a compressor 1327. Compressed hydrogen can enter the main furnace 1325 together with the dried iron ore or metal oxide. In some embodiments, the compressed hydrogen is preheated 1326 before entering the main furnace 1325. In the pre-reduction chamber 1324, hydrogen can pre-reduce the iron ore or metal oxide. 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 in a hydrogen plasma smelting reaction (HPSR) and / or a molecular hydrogen reduction reaction. HPSR can reduce metal oxides with a lower heat demand than reactions that rely only on molecular hydrogen.

[0103] The reduction products from the main furnace 1325 can be liquid iron / metal, matte, slag, or steel. The reduction products can be transferred to a ladle furnace, which can refine the liquid iron / metal or steel. The slag produced by the HPSR and / or molecular hydrogen reduction in the main furnace 1325 can enter the slag granulation system.

[0104] To further improve energy efficiency, residual materials can be recovered from the pre-reduction chamber 1324 and the main furnace 1325. The residual materials may include solids such as unreacted iron ore / metal oxides as well as waste gases, gangue elements, or water vapor. The waste gases may leave the main furnace 1325 and / or the pre-reduction chamber 1324, where they may pass through a recuperator 1328. The recuperator 1328 may perform countercurrent heat exchange and recover heat energy from the waste gases to preheat hydrogen or other reducing gases in a preheater 1326. After the waste gases leave the recuperator 1328, an electrostatic precipitator 1329 may be used to separate the residual iron ore / metal oxide dust from the waste gases.

[0105] The exhaust gas can leave the electrostatic precipitator 1329 and enter the scrubber / condenser 1331, where hydrogen and other gases can be separated from gangue elements and / or water vapor. After leaving the scrubber 1331, the gas can re-enter the compressor 1332 to be used again in another reduction reaction in the pre-reduction chamber 1324.

[0106] definition

[0107] Unless otherwise defined, all technical terms, symbols and other technical and scientific terms or nouns used herein are intended to have the same meaning as commonly understood by one of ordinary skill in the art to which the claimed subject matter belongs. In some cases, terms with commonly understood meanings are defined herein for clarity and / or for ease of reference, and the inclusion of such definitions herein should not necessarily be construed as indicating a substantial difference from what is generally understood in the art.

[0108] Reference herein to "about" a value or parameter includes (and describes) variations for that value or parameter itself. For example, a description referring to "about X" includes a description of "X". In addition, reference to the expression "less than," "greater than," "at most," "at least," "less than or equal to," "greater than or equal to," or other similar expressions followed by a list of values ​​or parameters is intended to apply the expression to each value or parameter in the list of values ​​or parameters.

[0109] As used herein, the singular forms "a", "an", and "the" are intended to include the plural forms as well, unless the context clearly indicates otherwise. It should also be understood that, as used herein, the term "and / or" refers to and encompasses any and all possible combinations of one or more of the associated listed items. It should also be understood that when used herein, the terms "includes", "including", "comprises", and / or "comprising" specify the presence of stated features, integers, steps, operations, elements, components, and / or units, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, units, and / or groups thereof.

[0110] The present application discloses several numerical ranges in the text and drawings. The disclosed numerical ranges inherently support any range or value within the disclosed numerical ranges, including endpoints, even if the specification does not verbatim state the precise range limitations, because the present disclosure can be implemented within the entire disclosed numerical range.

[0111] The above description is presented to enable those skilled in the art to implement and use the present disclosure, and is provided in the context of specific applications and their requirements. Various modifications to the preferred embodiments will be 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 present disclosure. Therefore, the present invention is not intended to be limited to the embodiments shown, but should conform to the widest scope consistent with the principles and features disclosed herein.

Claims

1. A furnace for molten metal production, the furnace comprising: a housing having a top portion and a bottom portion, wherein the housing contains a plurality of injectors configured to inject a fluid into the furnace; a furnace roof connected to the top portion of the shell, wherein the shell and / or furnace roof comprises a plurality of feed ports configured to introduce metal oxides into the furnace; as well as a hearth connected to the bottom portion of the housing, wherein the furnace is configured to melt the metal oxide to form a molten bath comprising a slag layer comprising molten metal oxide and a metal layer comprising molten metal below the slag layer, and wherein the fluid reduces the molten metal oxides in the slag layer into molten metal.

2. The furnace of claim 1, wherein the plurality of injectors are configured to inject the fluid toward a working area of ​​the molten bath wherein metal oxides are present.

3. The furnace of any one of claims 1-2, wherein a first injector of the plurality of injectors is configured to inject fluid toward a region of the molten bath.

4. The furnace of claim 3, wherein a second injector of the plurality of injectors is configured to inject fluid toward a second region of the molten bath that is different from the first region of the molten bath.

5. The furnace of any one of claims 1-4, wherein at least one of the plurality of injectors is configured to inject the fluid into the molten bath.

6. The furnace of claim 5, wherein the at least one of the plurality of injectors is configured to inject the fluid into the slag layer of the molten bath.

7. The furnace of claim 6, wherein the at least one of the plurality of injectors is an injector submerged in the molten bath.

8. The furnace of claim 7, wherein the at least one of the plurality of injectors is an injector submerged in the slag layer.

9. The furnace of claim 8, wherein the at least one of the plurality of injectors is an injector submerged in the molten bath in contact with both the slag layer and the metal layer.

10. The furnace of any one of claims 1-9, wherein the shell 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 of a cross section of the shell perpendicular to the internal axis.

11. The furnace of any one of claims 1-10, wherein the furnace roof comprises a second plurality of injectors configured to inject fluid into the furnace.

12. The furnace of any one of claims 1-11, wherein the plurality of injectors are configured to inject a fluid such that the fluid agitates the slag layer and / or metal layer in the furnace.

13. The furnace of any one of claims 1-12, wherein the plurality of injectors are configured to inject fluid such that a slag layer and / or a metal layer of the molten bath swirls within the furnace.

14. The furnace of any one of claims 1-13, wherein the plurality of injectors are equally spaced around the circumference of the shell.

15. The furnace of any one of claims 1-14, wherein the fluid comprises hydrogen, a hydrogen-containing gas, a carbon-containing gas, or a combination thereof.

16. The furnace of any one of claims 1-15, wherein the plurality of injectors comprises at least one of a lance, a submerged tuyeres, 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.

17. The furnace of claim 16, wherein the plasma torch sprays fluid at a temperature above the melting point of the metal oxide.

18. The furnace of claim 16, wherein the coherent jet comprises at least one of a supersonic coherent jet, a subsonic coherent jet, or a coherent jet with an enveloping flame.

19. The furnace of any one of claims 1-18, wherein the furnace roof comprises at least one electrode extending from the furnace roof toward the hearth, and the hearth comprises at least one counter electrode, wherein the furnace is configured to generate an arc between a distal end of the at least one electrode and the at least one counter electrode.

20. The furnace of claim 19, wherein the electric arc is between the distal end of the at least one electrode and the molten bath of the furnace.

21. The furnace of any one of claims 19-20, wherein the distal end of the at least one electrode is above the slag layer of the molten bath.

22. The furnace of any one of claims 19-20, wherein the distal end of the at least one electrode is immersed in the slag layer and / or metal layer of the molten bath.

23. The furnace of any one of claims 19 to 22, wherein the at least one counter electrode is embedded within the furnace bed.

24. The furnace of any one of claims 19-23, wherein the arc is a transferred or non-transferred arc.

25. The furnace of any one of claims 19-24, wherein the electric arc is configured to melt the metal oxide.

26. A furnace as claimed in any one of claims 19 to 25 wherein, under AC or DC operation, at any given time, the at least one electrode is a cathode and the at least one counter electrode is an anode.

27. The furnace of any one of claims 19-26, wherein the at least one electrode comprises a port extending through a central axis of the at least one electrode.

28. The furnace of claim 27, wherein the fluid is injected into the furnace through the port of the at least one electrode.

29. The furnace of any one of claims 19-26, wherein the electrode is solid and the fluid is injected only through the plurality of injectors.

30. The furnace of any one of claims 19-29, wherein at least a portion of the fluid injected into the furnace passes through the arc to form a plasma.

31. The furnace of claim 30, wherein the plasma melts the metal oxide, maintains the metal layer and slag layer in a molten phase, supplies thermal energy to the furnace, supplies ionized gas to the bath, and / or reduces the metal oxide.

32. The furnace of any one of claims 19-31, wherein the furnace roof comprises a plurality of electrodes extending from the furnace roof toward a hearth of the furnace, wherein the furnace is configured to generate an arc between a distal end of each electrode of the plurality of electrodes and the at least one counter electrode.

33. The furnace of claim 32, wherein the distances between the plurality of electrodes are such that there is no arc interference between the arc of each electrode and the at least one counter electrode.

34. The furnace of claim 32, wherein the distances between the plurality of electrodes are such that there is arc interference between the arcs of each electrode and the at least one counter electrode such that the arcs merge toward the center of the bath.

35. The furnace of any one of claims 19-34, wherein the at least one electrode and / or at least one counter electrode comprises graphite, titanium, tungsten, tantalum, zirconium or copper.

36. The furnace of any one of claims 19-35, wherein the electric arc agitates the molten bath.

37. The furnace of any one of claims 1-36, wherein the plurality of feed ports are configured so that feed ports closer to the center of the furnace roof introduce more metal oxide into the furnace than feed ports farther from the center of the furnace roof.

38. The furnace of any one of claims 1-37, wherein the suitability of the metal oxide for the method is determined by the thermodynamic potential for reduction of the injected and / or ionized fluid, such as iron oxides, chromium oxides, nickel oxides, copper oxides, and phosphorus oxides in embodiments where ionized and / or molecular hydrogen is present.

39. The furnace of any one of claims 1-38, wherein the metal oxide comprises iron oxide, hematite, magnetite, or a combination thereof.

40. The furnace of any one of claims 1-39, wherein the molten metal comprises metallic iron.

41. The furnace of any one of claims 1-40, wherein the housing contains at least one heat exchanger.

42. The furnace of claim 41, wherein the at least one heat exchanger comprises water cooling.

43. The furnace of any one of claims 1-42, wherein the shell comprises water-cooled copper.

44. The furnace of any one of claims 1-43, wherein the interior of the shell comprises a castable refractory lining or state of the art technology for enhancing furnace integrity.

45. The furnace of any one of claims 1-44, wherein the plurality of injectors are configured to inject a flux source or a metal oxide into the furnace.

46. ​​The furnace of claim 45, wherein the fluid is injected in combination with a solid such as a flux or a fine metal oxide, wherein the flux or injected metal oxide acts as bubble nucleation sites for injected gas to increase the reaction surface area between the fluid and the metal oxide in the slag layer.

47. The furnace of any one of claims 1-44, wherein the plurality of injectors are configured to inject a carbon source into the furnace.

48. The furnace of claim 47, wherein the carbon source is a solid carbon source.

49. The furnace of claim 48, wherein the solid carbon source is injected into the metal bath to effect carburization.

50. The furnace of any one of claims 1-44, wherein carburization of the molten metal is performed in a downstream ladle metallurgy process.

51. A method of forming a molten metal, the method comprising: introducing metal oxides or metal mixtures into the furnace through a plurality of feed ports in the furnace roof and / or the sides of the furnace; melting the metal oxide in the furnace to form a molten bath, the molten bath comprising a slag layer comprising molten metal oxide and a metal layer comprising molten metal below the slag layer; A fluid is introduced into the furnace through a plurality of injectors in the side of the furnace, wherein the fluid reduces the molten metal oxides in the slag layer to molten metal.

52. The method of claim 51 wherein the fluid is introduced in a direction toward a working zone of the molten bath wherein the metal oxide is reduced.

53. The method of any one of claims 51-52, wherein the fluid is introduced toward an adjacent injector and / or an adjacent working area.

54. The method of any one of claims 51-53, wherein the fluid is introduced into the molten bath.

55. The method of claim 54, wherein the fluid is introduced into the slag layer of the molten bath.

56. The method of claim 54, wherein the fluid is introduced into the metal layer of the molten bath, wherein the metal layer has a lower viscosity than the slag layer and thereby results in reduced bubble diameters being formed from the injected fluid.

57. The method of any one of claims 51-56, wherein the fluid is introduced at an angle of less than 90 degrees relative to a line tangent to each injector of a cross section of the housing perpendicular to the internal axis.

58. The method of any one of claims 51-57, wherein the fluid is introduced so that the fluid agitates the molten bath in the furnace to produce a uniform slag composition and enhances separation of metal particles contained in the slag so that the metal particles accumulate in the metal layer below the slag layer.

59. The method of any one of claims 51-58, wherein the fluid is introduced so that the molten bath swirls within the furnace.

60. The method of any one of claims 51-59, wherein the plurality of injectors are equally spaced around the circumference of the housing.

61. The method of any one of claims 51-60, wherein the fluid comprises hydrogen.

62. The method according to any one of claims 51-61, further comprising generating an arc between a distal end of at least one electrode extending from the furnace top toward the furnace bottom and at least one counter electrode at the furnace bottom, wherein the arc is configured to melt the metal oxide or provide thermal energy to the bath.

63. The method of claim 62, wherein the electric arc is between the distal end of the at least one electrode and the molten bath of the furnace.

64. The method of any one of claims 62-63, further comprising introducing the fluid into the furnace through a port extending through a central axis of the at least one electrode.

65. The method of any one of claims 62-64, further comprising generating a plasma from the introduced fluid and the arc.

66. The method of any one of claims 62-65, wherein the electric arc agitates the molten bath.

67. A method according to any one of claims 62 to 66, the method introducing more metal oxide into the furnace through feed ports closer to the centre of the furnace roof than through feed ports further from the centre of the furnace roof.

68. The method of any one of claims 62-67, wherein the metal oxide comprises iron ore.

69. The method of any one of claims 62-68, wherein the metal oxide comprises iron oxide, hematite, magnetite, a waste stream containing iron oxide, or a combination thereof.

70. The method of claim 69, wherein the iron ore is in the form of fines, lumps, pellets, sinter and / or a mixture of metal oxides.

71. The method of any one of claims 62-70, wherein the molten metal comprises metallic iron.

72. The method of any one of claims 62-71, further comprising introducing a carbon source into the furnace through the plurality of feed ports and / or through the plurality of injectors.

73. The method of claim 72, wherein the carbon source is a solid carbon source for carburizing the metallic iron.

74. A method as claimed in any one of claims 62 to 72 wherein any fluid injected into the slag layer partially escapes without reducing the iron ore.

75. The method of claim 74, wherein the fluid escaping from the slag layer generates plasma around the arc.

76. The method of any one of claims 72-75, wherein ionized fluid surrounding the arc is drawn into the slag layer by the arc momentum.

77. The method of claim 76, wherein the ionized fluid reduces the metal oxides in the slag layer near the arc.

78. The method of claim 76, wherein the ionized fluid surrounding the arc becomes non-ionized, thereby exothermically promoting heat generation in the furnace.

79. The method of any one of claims 72-78, wherein the furnace is a DC or AC electric arc furnace.

80. The process of any one of claims 51-79, wherein the process is run in batch, continuous or semi-continuous mode.

81. The method of claim 80, wherein the metal is tapped continuously and a slag high in metal oxide content may be processed batchwise by adding fluid injection to reduce the metal oxides in the slag.

82. The method of claim 80, wherein a first furnace produces a high metal oxide content slag and a metal layer, and a second furnace is in communication with the first furnace to receive the slag.

83. The method of claim 82, wherein the second furnace comprises a method according to any one of claims 51-79 to reduce the metal oxides contained in the slag.

84. The method of any one of claims 51-79, wherein the reduction reaction is primarily operated at high levels of metal oxides in the slag layer to increase hydrogen utilization of the process.

85. The method of any one of claims 51-79 and 84, wherein prior to tapping the slag, injection of the reducing agent is increased to reduce the level of the metal oxides in the slag before tapping.

86. A furnace for molten metal production, the furnace comprising: a housing having a top portion and a bottom portion, wherein the housing contains a plurality of injectors configured to inject a fluid into the furnace; a furnace roof connected to the top portion of the shell, wherein the shell and / or furnace roof include a plurality of feed ports configured to introduce molten metal oxide into the furnace; and a hearth connected to the bottom portion of the housing, wherein the furnace is configured to maintain the molten metal oxide in its molten state and the fluid reduces the molten metal oxide to molten metal.

87. The furnace of claim 86, wherein said plurality of injectors are configured to inject said fluid toward said molten metal oxide.

88. The furnace of any one of claims 86-87, wherein a first injector of the plurality of injectors is configured to inject fluid toward the region of molten metal oxide.

89. The furnace of claim 88, wherein a second injector of the plurality of injectors is configured to inject fluid toward a second region of the molten metal oxide that is different from the first region of the molten metal oxide.

90. The furnace of any one of claims 86-89, wherein at least one of said plurality of injectors is configured to inject said fluid into said molten metal oxide.

91. The furnace of claim 90, wherein said at least one of said plurality of injectors is an injector submerged in said molten metal oxide.

92. The furnace of claim 90, wherein at least one of said plurality of injectors is an injector submerged in said molten metal.

93. The furnace of claim 90 wherein said at least one of said plurality of injectors is a submerged injector in contact with both said molten metal oxide and molten metal.

94. The furnace of any one of claims 86-93, wherein the shell 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 of a cross-section of the shell perpendicular to the internal axis.

95. The furnace of any one of claims 86-94, wherein the furnace roof comprises a second plurality of injectors configured to inject fluid into the furnace.

96. The furnace of any one of claims 86-95, wherein the plurality of injectors are configured to inject a fluid such that the fluid agitates the molten metal oxide and / or molten metal in the furnace.

97. The furnace of any one of claims 86-96, wherein the plurality of injectors are configured to inject fluid such that the molten metal oxide and / or molten metal swirls within the furnace.

98. The furnace of any one of claims 86-97, wherein the plurality of injectors are equally spaced around the circumference of the shell.

99. The furnace of any one of claims 86-98, wherein the fluid comprises hydrogen, a hydrogen-containing gas, a carbon-containing gas, or a combination thereof.

100. The furnace of any one of claims 86-99, wherein the plurality of injectors comprises at least one of a lance, a submerged tuyeres, 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.

101. The furnace of claim 100, wherein the plasma torch sprays a fluid at a temperature above the melting point of the metal oxide.

102. The furnace of claim 100, wherein the coherent jet comprises at least one of a supersonic coherent jet, a subsonic coherent jet, or a coherent jet having an enveloping flame.

103. The furnace of any one of claims 86-102, wherein the furnace top includes at least one electrode extending from the furnace top toward the furnace bed, and the furnace bed includes at least one counter electrode, wherein the furnace is configured to generate an arc between a distal end of the at least one electrode and the at least one counter electrode.

104. The furnace of claim 103, wherein the electric arc is between the distal end of the at least one electrode and the molten metal oxide and / or molten metal of the furnace.

105. The furnace of any one of claims 103-104, wherein the distal end of the at least one electrode is above the molten metal oxide.

106. The furnace of any one of claims 103-104, wherein the distal end of the at least one electrode is immersed in the molten metal oxide and / or molten metal.

107. The furnace of any one of claims 103-106, wherein the at least one counter electrode is embedded within the furnace bed.

108. The furnace of any one of claims 103-107, wherein the arc is a transferred or non-transferred arc.

109. The furnace of any one of claims 103-108, wherein under AC or DC operation, at any given time, the at least one electrode is a cathode and the at least one counter electrode is an anode.

110. The furnace of any one of claims 103-109, wherein the at least one electrode comprises a port extending through a central axis of the at least one electrode.

111. The furnace of claim 110, wherein the fluid is injected into the furnace through the port of the at least one electrode.

112. The furnace of any one of claims 103-111, wherein said electrode is solid and said fluid is injected only through said plurality of injectors.

113. The furnace of any one of claims 103-112, wherein at least a portion of the fluid injected into the furnace passes through the arc to form a plasma.

114. The furnace of claim 113, wherein the plasma maintains the molten metal oxide and / or molten metal in its molten state, supplies thermal energy to the furnace, supplies ionized gas to the molten metal oxide and / or molten metal, and / or reduces the molten metal oxide.

115. The furnace of any one of claims 103-114, wherein the furnace roof comprises a plurality of electrodes extending from the furnace roof toward the furnace bed, wherein the furnace is configured to generate an arc between a distal end of each electrode of the plurality of electrodes and the at least one counter electrode.

116. The furnace of claim 115, wherein the distance between the plurality of electrodes is such that there is no arc interference between the arc of each electrode and the at least one counter electrode.

117. The furnace of claim 115, wherein the distances between the plurality of electrodes are such that there is arc interference between the arcs of each electrode and the at least one counter electrode such that the arcs merge toward the center of the molten metal oxide.

118. The furnace of any one of claims 103-117, wherein the at least one electrode and / or the at least one counter electrode comprises graphite, titanium, tungsten, tantalum, zirconium or copper.

119. The furnace of any one of claims 103-118, wherein the electric arc agitates the molten bath.

120. The furnace of any one of claims 86-119, wherein the plurality of feed ports are configured so that feed ports closer to the center of the furnace top introduce more molten metal oxide into the furnace than feed ports further from the center of the furnace top.

121. The furnace of any one of claims 86-120, wherein the suitability of the molten metal oxides for the process is determined by the thermodynamic potential for reduction by the injected and / or ionized fluids, such as iron oxides, chromium oxides, nickel oxides, copper oxides, and phosphorus oxides in embodiments where ionized and / or molecular hydrogen is present.

122. The furnace of any one of claims 86-121, wherein the molten metal oxide comprises iron oxide, hematite, magnetite, or a combination thereof.

123. The furnace of any one of claims 86-122, wherein the molten metal comprises metallic iron.

124. The furnace of any one of claims 86-123, wherein the housing contains at least one heat exchanger.

125. The furnace of claim 124, wherein the at least one heat exchanger comprises water cooling.

126. The furnace of any one of claims 86-125, wherein the shell comprises water-cooled copper.

127. The furnace of any one of claims 86-126, wherein the interior of the shell comprises a castable refractory lining or state of the art technology for enhancing furnace integrity.

128. The furnace of any one of claims 86-127, wherein the plurality of injectors are configured to inject a flux source or a metal oxide into the furnace.

129. A furnace according to claim 128, wherein the fluid is injected in combination with a solid such as a flux or a fine metal oxide, wherein the flux or injected metal oxide acts as bubble nucleation sites for the injected gas to increase the reaction surface area between the fluid and the metal oxide in the slag layer.

130. The furnace of any one of claims 86-129, wherein the plurality of injectors are configured to inject a carbon source into the furnace.

131. The furnace of claim 130, wherein the carbon source is a solid carbon source.

132. The furnace of claim 131 wherein the solid carbon source is injected into the metal bath to perform carburization.

133. The furnace of any one of claims 86-132, wherein carburization of the molten metal is performed in a downstream ladle metallurgy process.

134. A method of forming a molten metal, the method comprising: introducing molten metal oxide into the furnace through a plurality of feed ports in the furnace roof and / or the furnace sides; maintaining said molten metal oxide in said furnace in its molten state; as well as A fluid is introduced into the furnace through a plurality of injectors in the side of the furnace, wherein the fluid reduces the molten metal oxides to molten metal.

135. The method of claim 134, wherein the fluid is introduced in a direction toward the molten metal oxide in the furnace.

136. The method of any one of claims 134-135, wherein the fluid is introduced toward an adjacent injector.

137. The method of any one of claims 134-136, wherein the fluid is introduced into the molten metal oxide.

138. The method of claim 137, wherein the fluid is introduced into the molten metal, wherein the molten metal has a lower viscosity than the molten metal oxide and thereby results in reduced bubble diameters formed from the jetted fluid.

139. The method of any one of claims 134-138, wherein the fluid is introduced at an angle of less than 90 degrees relative to a line tangent to each injector of a cross section of the housing perpendicular to the internal axis.

140. The method of any one of claims 134-139, wherein the fluid is introduced so that the fluid agitates the molten metal oxide in the furnace to produce a uniform slag composition and enhances the separation of metal particles contained in the slag so that the metal particles are accumulated in a metal layer below the slag layer.

141. The method of any one of claims 134-140, wherein the fluid is introduced so as to cause the molten metal oxide to swirl within the furnace.

142. The method of any one of claims 134-141, wherein the plurality of injectors are equally spaced around the circumference of the housing.

143. The method of any one of claims 134-142, wherein the fluid comprises hydrogen and / or carbon.

144. The method according to any one of claims 134-143, further comprising generating an arc between a distal end of at least one electrode extending from the furnace top toward the furnace bottom and at least one counter electrode at the furnace bottom, wherein the arc is configured to provide thermal energy to the bath.

145. The method of claim 144, wherein the electric arc is between the distal end of the at least one electrode and the molten metal oxide and / or molten metal of the furnace.

146. The method of any one of claims 144-145, further comprising introducing the fluid into the furnace through a port extending through a central axis of the at least one electrode.

147. The method of any one of claims 144-146, further comprising generating a plasma from the introduced fluid and the arc.

148. The method of any one of claims 144-147, wherein the electric arc agitates the molten metal oxide and / or molten metal.

149. The method of any one of claims 134-148, wherein more molten metal oxide is introduced into the furnace through a feed port closer to the center of the furnace top than a feed port further from the center of the furnace top.

150. The method of any one of claims 134-149, wherein the molten metal oxide comprises iron ore.

151. The method of any one of claims 134-150, wherein the molten metal oxide comprises iron oxide, hematite, magnetite, a waste stream containing iron oxide, or a combination thereof.

152. The method of any one of claims 62-70, wherein the molten metal comprises metallic iron.

153. The method of any one of claims 134-152, further comprising introducing a carbon source into the furnace through the plurality of feed ports and / or through the plurality of injectors.

154. The method of claim 153, wherein the carbon source is a solid carbon source used to carburize the metallic iron.

155. The method of any one of claims 134-154, wherein any fluid injected into the slag layer partially escapes without reducing the molten metal oxide.

156. The method of claim 155, wherein the fluid escaping from the molten metal oxide generates a plasma around the arc.

157. The method of claim 156, wherein the ionized fluid surrounding the arc is drawn into the molten metal oxide by the arc momentum.

158. The method of claim 157, wherein the ionized fluid reduces the molten metal oxide near the arc.

159. The method of claim 157, wherein the ionized fluid surrounding the arc becomes non-ionized, thereby exothermally promoting heat generation in the furnace.

160. The method of any one of claims 134-159, wherein the furnace is a DC or AC electric arc furnace.

161. The method of any one of claims 134-160, wherein the method is run in batch, continuous or semi-continuous mode.

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