Ultrahigh temperature continuous reduction and subsequent selective separation of metal compound particles

Abstract

A continuous process for converting metal compound particles into an elemental metal mixture. Metal compound particles and a reducing agent are introduced into an ultra-high temperature reaction zone having a temperature higher than 2700 DEG C and an oxygen content of less than 3 vol%. The particle size d90 of the metal compound particles is 500 [mu] m. The residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 1 minute sufficient to mix and react with a reducing agent to reduce the metal compound particles to form an elemental metal mixture. The elemental metal mixture is removed from the ultra-high temperature reaction zone. The one or more elemental metals are separated or concentrated from the elemental metal mixture in one or more separation zones based on the different sizes and densities of the one or more elemental metals and the remaining elemental metal mixture.

Description

BACKGROUND OF THE INVENTION

[0001] The present disclosure relates to a continuous process for converting metal compound particles into a mixture of elemental metals using an ultra-high temperature reduction process. The present disclosure also relates to a process for selectively separating or concentrating one or more elemental metals from a mixture of elemental metals.

[0002] The processing of minerals or metal ores into their corresponding elemental metals has been carried out for centuries. Minerals or metal ores typically contain one or more metal oxides or metal hydroxides. Two examples of minerals or metal ores are naturally occurring bauxite (Al(OH)3) and hematite (Fe2O3), from which two of the most commonly used metals on Earth are produced. There are mainly four methods for converting metal ores into elemental metals. Electrolytic reduction, carbothermal reduction reaction, CO reduction of metal ores, and hydrogen reduction of metal ores. Aluminum ores and copper ores are typically processed into their elemental metals by electrolytic reduction. Iron ores are typically processed in a blast furnace by a carbothermal reaction combined with CO reduction. The reactivity of the metal typically determines the method by which the metal ore is reduced to the elemental metal form. Metals with a higher reactivity than carbon are processed by electrolytic reduction. Metals with a lower reactivity than carbon can be reduced to elemental metals by a carbothermal reaction.

[0003] There are well-established processing methods and stable markets for many commonly used metals. An increasingly important need is to process less common high-value metals, namely rare earth element (REE) metals, high-value transition metals, and other high-value metals and metalloids. Rare earth elements are used in catalysts, permanent magnets, glass, metallurgy, batteries, ceramics, pigments, phosphors, electronic devices, photovoltaics, military applications, etc. Indium is an example of a critical metal, and its supply is difficult to meet the demand as a major component of transparent electrodes used in telephones, computer displays, and other applications. Due to the growing demand for lithium-ion batteries, lithium is an example of a valuable alkali metal. Reduced alkali metals and alkaline earth metals will maintain their elemental state and will not be oxidized if stored in an oxygen-poor environment.

[0004] An ore is a naturally occurring solid substance from which a metal or valuable mineral can be extracted. An ore can be a rock or powdered mineral containing one or more metal oxides or one or more metal minerals. A metal mineral is a compound of a metal, which means that the metal is not in its elemental state. Iron ore is typically considered to be iron oxide (Fe2O3). Another iron-containing mineral is pyrite (FeS2). Rare earth element (REE) metals, transition metals, and other valuable metals and critical metals are typically present in trace amounts in rocks, mineral powders, or other metal ores in the form of oxide ores or other minerals. Taking rare earth element metals as an example, the common methods for recovering rare earth elements are:

[0005] Crush rocks, ores, and mineral sources as needed to release particles containing REE metals from the matrix.

[0006] Perform a flotation process to concentrate the particles containing REE metals.

[0007] Dissolve the oxide particles and mineral particles containing REE metals in the flotation concentrate.

[0008] Perform solvent extraction techniques to separate the target REE metals from the bulk solution.

[0009] Precipitate the target REE metals from the solution.

[0010] If the purified target REE metal precipitate is the target material, the method is complete. The final product precipitate is typically an oxide or salt of the target REE metal.

[0011] If the elemental REE metal is the target material, further processing is required to convert the purified REE metal precipitate into purified REE elemental metal. Since REE oxides are stable, reduction to elemental metal is difficult.

[0012] The most common method is a multi-step chloride reduction process, which generates large amounts of toxic waste.

[0013] A molten salt electrorefining method similar to the aluminum production process is being studied.

[0014] In summary, critical elemental metals, strategic elemental metals, and rare earth elemental metals are important and growing components of high-performance electronics and other industrial materials. These metals are typically extracted with acids, generating vast amounts of acid leach waste materials that are highly harmful and costly. In addition, the efficiency of this acid extraction method is very low.

[0015] A faster, more economical, and less waste-generating method for extracting rare earth elemental metals, transition metals, and other valuable metals from large deposits would be an advancement in the field.

[0016] Fine particulate waste generated during coal mining is a major environmental problem. In the United States and other countries, fine particulate waste generated from coal mining is processed in slurry impoundments. An article in The Washington Post, "Many coal sludge impoundments have weak walls, federal study says" (https: / / www.washingtonpost.com / national / health-science / many-coal-sludge-impoundments-have-weak-walls-federal-study-says / 2013 / 04 / 24 / 76c5be2a-acf9-11e2-a8b9-2a63d75b5459_story.html), cited data from the Mine Safety and Health Administration that there are 596 slurry impoundments in 21 states. These impoundment sites represent millions of tons of fine particulate waste. Potential environmental problems include dam failures, mudslides, and slurry sliding into valleys, rivers, roads, and communities, dissolved and suspended solids polluting groundwater, acidic water discharging into groundwater and surface water, etc.

[0017] There are approximately 430 coal ash ponds (https: / / insideclimatenews.org / news / 29062009 / epa-releases-secret-list-44-high-risk-coal-ash-ponds / ) across the United States storing ash generated from burning coal, with similar environmental problems. The U.S. Environmental Protection Agency (EPA) reported that there are 1,000 coal ash storage sites (https: / / www.alleghenyfront.org / the-cautionary-tale-of-the-largest-coal-ash-waste-site-in-the-u-s / ), including ponds storing wet waste or landfills storing dry waste. There are ash storage sites around the world filled with solid waste generated from burning coal.

[0018] A new method for cleaning or rehabilitating slurry ponds and waste sites associated with fine particulate coal waste and coal ash waste and also extracting valuable components from the waste sites would have environmental and economic benefits. Summary of the Invention

[0019] The disclosed invention relates to a continuous method for converting metal compound particles into a mixture of elemental metals. The disclosed invention also relates to a method for selectively separating or concentrating one or more elemental metals from the mixture of elemental metals.

[0020] In the disclosed reduction method, metal compound particles and a reducing agent are introduced into an ultra-high temperature reaction zone.

[0021] The residence time of the metal compound particles in the ultra-high temperature reaction zone is sufficient to mix and react with the reducing agent, thereby reducing the metal compound particles to form an elemental metal mixture. In some embodiments, the residence time is less than 1 minute. In some embodiments, the residence time is less than 50 seconds, 40 seconds, 30 seconds, 25 seconds, 20 seconds, 18 seconds, 16 seconds, 14 seconds, 12 seconds, 10 seconds, 9 seconds, 8 seconds, 7 seconds, 6 seconds, 5 seconds, 4 seconds, 3 seconds, 2 seconds, and 1 second.

[0022] The ultra-high temperature reaction zone can operate at a temperature above 2700 °C. In some embodiments, the ultra-high temperature reaction zone can operate at a temperature above 2500 °C. In some embodiments, the ultra-high temperature reaction zone can operate at a temperature above 2000 °C. In some embodiments, the ultra-high temperature reaction zone can operate at a temperature above 1850 °C. In some embodiments, the ultra-high temperature reaction zone can operate in a temperature range of 1850 °C to 3000 °C.

[0023] The ultra-high temperature reaction zone can have a lean oxygen environment or an oxygen-deficient environment. The oxygen content of the ultra-high temperature reaction zone can be less than 3 vol%. In some embodiments, the oxygen content can be less than 2 vol%. In some embodiments, the oxygen content can be less than 1 vol%. In some embodiments, the oxygen content can be less than 0.5 vol%. In some embodiments, the oxygen content can be less than 0.2 vol%. In some embodiments, the oxygen content can be less than 0.1 vol%.

[0024] The particle size of the metal compound particles is less than 1 mm. In some embodiments, the d90 particle size of the metal compound particles is 500 μm. The d90 particle size of the metal compound particles is 200 μm. The d90 particle size of the metal compound particles is 100 μm. The d90 particle size of the metal compound particles is 50 μm. The particle size can be measured by one or more conventional methods, such as sieving or a particle size analyzer, including a laser diffraction particle size analyzer.

[0025] In the reduction method, a gas, vapor, liquid, and / or entrained solid particles containing the elemental metal mixture are removed from the ultra-high temperature reaction zone.

[0026] Based on the different physical properties of one or more elemental metals and the remaining elemental metal mixture, one or more elemental metals can be separated from the elemental metal mixture in one or more separation zones. In some embodiments, the different physical properties include differences in size and density.

[0027] The metal compound particles include chemical derivatives of one or more metallic elements or metalloid elements, wherein the metallic element or metalloid element is ionically bonded to another atom and / or covalently bonded to another atom. In some non-limiting embodiments, the metal compound particles include one or more minerals, mineral aggregates, metal oxides, metal hydroxides, and / or metal salts. In some non-limiting embodiments, the metal compound particles include one or more rare earth metals. In some non-limiting embodiments, the metal compound particles include one or more transition metals.

[0028] The metal compound particles may include fine particulate coal waste generated in a mine or mining process. The metal compound particles may include coal ash waste.

[0029] The reducing agent may include carbon particles. The particle size of the carbon particles may be d90 10 μm. The particle size of the carbon particles may be d90 5 μm. The particle size d90 of the carbon particles is 1 μm. The particle size of the carbon particles is d50 100 nm.

[0030] The reducing agent may include hydrogen. The reducing agent may include carbon monoxide. The reducing agent may include hydrocarbons. The hydrocarbons may include coal. The hydrocarbons may include natural gas. The hydrocarbons may include liquid hydrocarbons. The reducing agent may include at least two of hydrogen, carbon monoxide gas, or natural gas.

[0031] The ultra-high temperature reaction zone with an oxygen-depleted environment may contain combustion gases discharged from a pulse combustor.

[0032] The disclosed invention also relates to a method for separating one or more elemental metals from an elemental metal mixture produced by ultra-high temperature reduction of metal compound particles. In one embodiment of the method, the temperature of the elemental metal mixture is higher than 1850 °C. The elemental metal mixture is placed inside a first cyclone operating at a first cyclone temperature, and one or more elemental metals are separated from the remaining elemental metal mixture based on the different sizes and / or densities of the one or more elemental metals and the remaining elemental metal mixture.

[0033] In one embodiment of the method, the remaining elemental metal mixture is placed inside a second cyclone operating at a second cyclone temperature, and one or more other elemental metals are separated from the other remaining elemental metal mixture based on the different sizes and / or densities of the one or more other elemental metals and the other remaining elemental metal mixture.

[0034] In one embodiment of the method, the remaining elemental metal mixture is placed in one or more subsequent cyclone separators connected in series and operated at different cyclone separator temperatures to separate one or more subsequent elemental metals from the subsequent remaining elemental metal mixture based on the different sizes and / or densities of one or more subsequent elemental metals and the subsequent remaining elemental metal mixture.

[0035] In one embodiment of the method, a temperature reduction of the remaining elemental metal mixture occurs between the first cyclone separator and the second cyclone separator. In one embodiment of the method, the temperature reduction is achieved with a heat exchanger. In one embodiment of the method, the temperature reduction is achieved by introducing a spray of liquid nitrogen. In one embodiment of the method, the temperature reduction is achieved by introducing a spray of water.

[0036] In one or more embodiments of the method, the first cyclone separator temperature is balanced with the temperature of the incoming elemental metal mixture.

[0037] The terms used herein are for the purpose of describing particular embodiments only and are not intended to be limiting. In this specification and the appended claims, many terms will be used, and these terms will be defined as set forth herein. Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. The singular forms also include the plural unless the context clearly dictates otherwise. Thus, the singular forms "a", "an", and "the" include plural referents unless the context clearly indicates otherwise.

[0038] As used herein, the expression [A], [B], [C], "and / or" [D] means one or more of the cases connected by the expression "and / or", which can occur alone or in combination. Thus, this expression means that [A] or [B] or [C] or [D] can occur alone, or any combination of two or more cases can occur, such as [A] and [B], [A] and [C], [B] and [C], [A], [C] and [D], etc.

[0039] As used herein, unless otherwise clearly stated or clearly implied, the term "about" means a range of values plus or minus 10% ("±10%"), e.g., about 1.0 includes values from 0.9 to 1.1.

[0040] Concentrations, amounts, and other numerical data may be expressed or presented herein in the form of ranges. It should be understood that the use of such range formats is merely for convenience and brevity and should therefore be interpreted flexibly as encompassing not only the explicitly recited numerical values that are the limits of the range, but also all individual numerical values or sub-ranges subsumed within that range as if each numerical value and sub-range were explicitly recited. By way of illustration, a numerical range of “about 1 to about 5” should be interpreted as encompassing not only the explicitly recited values of about 1 to about 5, but also the individual numerical values and sub-ranges within the indicated range. Thus, included within this numerical range are the individual numerical values (e.g., 2, 3, and 4) and sub-ranges (e.g., 1 - 3, 2 - 4, and 3 - 5). This same principle also applies to ranges that recite only one numerical value. Additionally, this interpretation shall apply regardless of the nature of the range or feature being described.

[0041] Throughout the specification, references to “one embodiment,” “an embodiment,” or similar language mean that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention. Thus, the phrases “in one embodiment,” “in an embodiment,” and similar language that appear throughout the specification may, but do not necessarily, all refer to the same embodiment. Additionally, although the following description refers to several embodiments and examples of the various components and methods of the described invention, all of the described embodiments and examples are considered illustrative only and not limiting in any way. Furthermore, the features, structures, characteristics, processes, or methods described for the present invention may be combined in any suitable manner in one or more embodiments.

[0042] It should be understood that the foregoing general description and the following detailed description are exemplary and explanatory and do not limit the claimed invention. It should be understood that the specific aspects and features of the disclosed invention may be freely combined with other specific aspects and features of the disclosed invention. It should be understood that the various embodiments are not limited to the arrangements and means shown in the drawings. It should also be understood that these embodiments may be combined, or other embodiments may be utilized, and structural changes may be made without departing from the scope of the various embodiments of the present invention, unless so stated. Thus, the following detailed description should not be construed in a limiting sense. BRIEF DESCRIPTION OF THE DRAWINGS

[0043] To facilitate an understanding of the manner in which the above and other features and advantages of the present invention are obtained, the present invention briefly described above will be described in more detail with reference to specific embodiments of the present invention shown in the accompanying drawings. It should be understood that these drawings depict only typical embodiments of the present invention and are therefore not considered to limit its scope, and the present invention will be described and explained with additional features and details by using the drawings, wherein:

[0044] Figure 1 Shows a process flow representing a non - limiting embodiment of an apparatus for preparing fine - grained waste from a coal mine reservoir or a coal ash reservoir.

[0045] Figure 2 Is an all - inclusive flowchart showing various non - limiting iterations, combinations, and variations of the disclosed invention.

[0046] Figure 3 Shows the concentrations of target metals detected in a fine - grained coal waste sample generated by a coal preparation plant, characterized by inductively coupled plasma atomic emission spectrometry (ICP - AES), the coal preparation plant having a flotation circuit for further cleaning tailings or fine - grained coal waste. The melting and boiling points of the metals are also shown by horizontal lines and vertical lines connecting them.

[0047] Figure 4 Shows the concentrations of target metals detected in a fine - grained coal waste sample generated by a coal preparation plant, characterized by ICP - AES, the coal preparation plant having a flotation circuit for further cleaning tailings or fine - grained coal waste. The melting and boiling points of the metals are also shown by horizontal lines and vertical lines connecting them. Compared with Figure 3 The concentrations of aluminum, iron, and silicon have been removed from the dataset to show the concentrations of other metals present.

[0048] Figure 5 Shows, by ICP - AES characterization, the concentrations of a selected group of metals detected from the Figure 3 and Figure 4 datasets shown. The melting and boiling points of the metals are also shown by horizontal lines and vertical lines connecting them.

[0049] Figure 6 Shows, by ICP - AES characterization, the concentrations of a selected group of metals detected from the Figure 3 and Figure 4 datasets shown. The melting and boiling points of the metals are also shown by horizontal lines and vertical lines connecting them. Compared with Figure 5 The concentrations of aluminum, iron, and silicon have been removed from the dataset to show the concentrations of other metals present.

[0050] Figure 7A comprehensive flow chart showing various non-limiting iterations, combinations, and variations of the disclosed invention is presented. The hollow triangle at the end of the ultra-high temperature reaction zone represents a nozzle that causes adiabatic cooling. Detailed Description

[0051] The present disclosure relates to a continuous process for converting metal compound particles into a mixture of elemental metals using an ultra-high temperature reduction process. The present disclosure also relates to a process for selectively separating or concentrating one or more elemental metals from the mixture of elemental metals.

[0052] As used herein, metal compound particles include one or more minerals, mineral aggregates, metal oxides, metal hydroxides, and / or metal salts. Metal compound particles include chemical derivatives of one or more metallic elements or metalloid elements, wherein the metallic element or metalloid element is ionically bonded to another atom and / or covalently bonded to another atom. In short, a metallic element is a compound of another element or elements, rather than in a pure elemental state.

[0053] The disclosed process introduces metal compound particles and a reducing agent into an ultra-high temperature reaction zone and rapidly heats the metal compound particles and the reducing agent under conditions where a chemical reaction occurs between the metal compound particles and the reducing agent.

[0054] As used herein, a reductant is a reducing agent or a substance that is capable of causing the reduction of another substance when it is oxidized itself. As used herein, the term reductant also includes an indirect reductant that is indirectly used as a reductant because it is converted into one or more reducing agents within the reaction zone. Non-limiting examples of reductants include carbon particles, hydrogen gas, carbon monoxide gas, and hydrocarbons. Hydrocarbons can be solid, liquid, or gaseous hydrocarbons. One non-limiting solid hydrocarbon is coal. One non-limiting gaseous hydrocarbon is compressed natural gas (CNG).

[0055] The ultra-high temperature reaction zone includes an oxygen-depleted environment or an oxygen-free environment. As used herein, the terms oxygen-depleted, oxygen-free, or very low excess oxygen refer to less than about 3 vol%, 2 vol%, 1 vol%, 0.5 vol%, 0.2 vol%, 0.1 vol% of O2, where any of the said values can form the upper or lower limit of a range.

[0056] As used herein, the term residence time refers to the time that metal compound particles and a reducing agent are exposed to the ultra-high temperature reaction zone and its oxygen-deficient environment. The residence time of the metal compound particles and the reducing agent in the ultra-high temperature reaction zone is less than about 1 minute. Due to the transport time within the method system equipment, the total residence time of the metal compound particles and the reducing agent in the ultra-high temperature reaction zone may be greater than 1 second. The residence time can be less than 60 seconds, 50 seconds, 40 seconds, 30 seconds, 25 seconds, 20 seconds, 18 seconds, 16 seconds, 14 seconds, 12 seconds, 10 seconds, 9 seconds, 8 seconds, 7 seconds, 6 seconds, 5 seconds, 4 seconds, 3 seconds, 2 seconds, and 1 second, where any of the said values can form the upper or lower limit of a range.

[0057] In one embodiment where the reducing agent comprises carbon particles, the carbon reacts with the metal compound particles, causing the metal compound particles to be immediately reduced to one or more elemental metals and carbon monoxide. The carbon will preferentially scavenge the oxygen in the metal compound particles, producing carbon monoxide and elemental metals. Then, the carbon monoxide can react with different metal compounds to reduce them to elemental metals. The combined metal molecules will separate into their respective metal components. The elemental metals preferably remain in a vapor or liquid state for easy separation and recovery.

[0058] The carbon can be the carbon inherent in a coal ash sample. The carbon can be an additive premixed with the metal compound particles before treatment. In this case, the carbon can be carbon particles, coke particles, graphite particles, biochar particles, and / or carbon black, and / or carbon black-like particles called microcarbon particles as described in U.S. Patent 11,505,464 B2. The particle size d90 of the carbon particles can be 50 microns. The particle size d90 of the carbon particles can be 10 microns. The particle size d90 of the carbon particles can be 1 micron. The particle size of the carbon particles can be d90 0.2 microns.

[0059] Then, the gaseous stream and / or liquid stream containing the sublimated metal gas or liquid metal or a mixture of gas and liquid metal can be cooled in a series of chambers, and the system will achieve selective condensation according to the specific boiling point / condensation point (but above its melting point) of each metal, causing the metal to condense in a molten state and can be collected at the bottom of the chamber / cyclone separator. Then, the remaining uncondensed gas can enter the second, third, and fourth chambers with surfaces / environments having gradually decreasing temperatures to condense metals with gradually decreasing boiling points. Depending on the density, the metals can be further separated in a molten state.

[0060] The system and method can allow for high-efficiency and rapid refining of metals, as well as the separation / recovery of metals from minerals including critical metals, rare earth metals, transition metals, and / or specialty metals.

[0061] The fine particle waste found in coal mine storage ponds or coal ash storage ponds is an ideal raw material candidate for the method described herein.

[0062] Figure 1 Shows a process flow representing a non-limiting embodiment of an apparatus for preparing fine particle waste from a coal mine reservoir or a coal ash reservoir, which is used in the methods of ultra-high temperature reduction and metal compound separation described herein. A dredger can be used to mine the slurry pond and form the solids deposited in the slurry into an initial slurry. Alternatively, wet filter cake, dry filter cake, or dry slurry pond solids can be dug out or directly placed into a metering system and then conveyed to a mixer to form a slurry with about 30 wt% to 50 wt% solids. The storage yard may have larger particles blended with the fine particle waste, and the larger particles are not ideal raw materials for ultra-high temperature reduction metal compound particles. Oversized particles can be separated from the slurry using a 2 mm sieve. In another embodiment, a 1 mm sieve is used. In another embodiment, a 0.5 mm sieve can be used. In another embodiment, a hydrocyclone can be used to classify and separate the fine particle waste and the larger solids not required in the method. The oversized material (such as oversize residue or hydrocyclone underflow) is separated out. If the oversized material has value as coal or aggregate, the material can be sold into these markets. The material can be ground and added back to the mixer.

[0063] In one embodiment, the particle size d90 is 0.5 mm. In other embodiments, the particle size d90 is 0.2 mm. In other embodiments, the particle size is less than d90 by 0.1 mm. In another embodiment, the particle size d90 is 0.05 mm.

[0064] The particle sizes and particle size distributions disclosed herein can be measured using sieving analysis techniques or commercially available particle size analyzers (such as laser diffraction particle size analyzers). The particle size distribution can be used to determine the average particle size, median particle size, and other relevant parameters defining the distribution. As used herein, unless otherwise clearly defined, the term "particle size" refers to the median particle size or "d50" size in the particle size distribution. The term "d50" size value refers to the size value at which 50% of the particles in the sample are smaller than this size value. Thus, by definition, d50 is the median particle size. More generally, the "dXX" size value refers to the size value at which XX% of the particles in the sample distribution are smaller than this size value. The particle sizes of d90 and d99 are also mentioned herein. For example, a particle size d99 of 200 microns (XX = 99 and "size value" = 200 microns) means that 99% of the particle sizes are smaller than 200 microns. Although the particle size of d50 represents the median particle size, the particle size of d99 represents the upper limit of the particle size.

[0065] The filtered slurry can be dewatered in a filter press with a high-pressure pump (such as a piston pump or a screw pump). Then a high-pressure extrusion step can be used to further dewater the filter cake. The filter cake discharged from the filter press contains about 15 wt% to 25 wt% solids. The filter cake is metered by a delumper and enters a dryer to make the crushed filter cake into powder. The dry powdered fine coal waste generated from a coal mine storage pond or a coal ash storage pond (such as the ash generated by a coal-fired power plant) enters the feed hopper of the ultra-high temperature reduction method. The dry powdered fine particles made from the fine coal waste generated by a coal preparation plant (such as generated from a slurry pond, a storage pond, etc.) can have an ash content of about 50 wt% and 50 wt% coal. This value varies according to the efficiency of the equipment in the coal preparation plant. The dry powdered fine waste generated from a coal ash storage site may be completely carbon-free (because it is a product of burning coal). There may be some unburned carbon coke in the ash, and its carbon content may be less than 20 wt%.

[0066] Figure 2 A comprehensive flow chart showing various non-limiting iterations, combinations, and variations of the disclosed invention.

[0067] The burner burns fuel and an oxygen-containing gas to produce an ultra-high temperature oxygen-deficient gaseous stream, which is the environment or condition for the ultra-high temperature reaction zone where the ultra-high temperature reduction of metal compounds occurs. The oxygen content in the oxygen-containing gaseous stream is concentrated, preferably greater than 85 vol%. In some embodiments, the oxygen content in the oxygen-containing gaseous stream is greater than 90 vol%. In some embodiments, the oxygen content in the oxygen-containing gaseous stream is greater than 92 vol%. If oxygen is concentrated from the atmosphere, then almost all of the remaining gas in the oxygen-containing gaseous stream is nitrogen. There are very small amounts of other gases. For example, CO2 from ambient air will also be present in the oxygen-containing gaseous stream in a low ppm range.

[0068] A valveless pulse combustor (VPC) is a preferred embodiment of the burner that creates an ultra-high temperature, oxygen-deficient environment for the reduction method. The fuel and the oxygen-containing gaseous stream are mixed and burned in the combustion chamber of the VPC.

[0069] One advantage of VPCs is that they can operate efficiently under near-stoichiometric combustion conditions. This means that the oxygen content in the combustion gas discharged from the VPC is very low while still maintaining a low CO content. If the CO increases significantly, the combustion efficiency is not high. In some embodiments, the oxygen content in the combustion gas is less than 3 vol% O2. In some embodiments, the oxygen content in the combustion gas is less than 2 vol% O2. The oxygen content in the combustion gas can be less than 1 vol%, or even less than 0.5 vol%. When the O2 in the combustion gas is 2 vol%, the CO can be <100 ppm. When the O2 in the combustion gas <1 vol%, the CO can be less than 300 ppm.

[0070] When the oxygen in the incoming oxygen-containing gaseous stream is > 85% by volume, the temperature of the combustion gas can exceed 2400 °C. When the oxygen is 90% by volume, the temperature of the combustion gas discharged from the VPC can be as high as 3000 °C or higher. When the oxygen is 94% by volume, the temperature of the combustion gas discharged from the VPC can be as high as 3300 °C or higher.

[0071] Non-limiting examples of methods for concentrating oxygen from air to produce an oxygen-containing gas with an oxygen content > 85% by volume include cryogenic gas separation, pressure swing absorption, membrane absorption, vacuum pressure swing absorption, ionic liquid-based absorption, dedicated liquid chemical-based absorption, aqueous salt gas absorption, dry absorption technology, and / or aqueous suspended solid gas absorption.

[0072] The fuel used in the VPC can be hydrogen. If H2 is burned in the VPC to generate heat for the reduction process, the main gas components in the combustion gas will be water vapor and some N2 from the > 85% by volume O2 gaseous stream required for high-temperature combustion. No CO2 is produced when H2 burns. The combustion equilibrium chemical reaction for the stoichiometric ratio of H2 is:

[0073] 2H2 + O2 → 2H2O.

[0074] The fuel used in the VPC can be hydrocarbon gas, such as natural gas, methane, propane, etc. The fuel used can be solid hydrocarbon fuel, such as lignite coal, brown coal, sub-bituminous coal, bituminous coal, anthracite, where the coal is dry powder with a moisture content of less than 1% by weight and a particle size of less than 150 μm. The fuel used can be solid hydrocarbon, such as solid bio-waste generated from dry forest waste, farm waste, sawdust, wood chip waste, human or animal fecal waste, plastic waste, rubber waste, automobile tire waste, etc., where the solid hydrocarbon fuel is dry powder with a moisture content of less than 1% by weight and a particle size of less than 150 μm. The fuel used can be liquid hydrocarbon, such as gasoline, diesel, biodiesel, biofuel, waste cooking oil, etc.

[0075] Fine particulate coal waste (e.g., material from a slurry pond generated during coal processing in a coal preparation plant) typically has about 25 wt% to 50 wt% coal particles (by mass). The remaining material is minerals, typically present in the form of aluminosilicates, silica, alumina, iron compounds (e.g., pyrite or iron oxide), calcium oxide, and other trace mineral components. Mineral raw materials containing metal compound particles (fine particulate coal waste) with solid hydrocarbons (e.g., fine coal particles) mixed with mineral particles have advantages as raw materials for this method. In the ultra-high temperature reaction zone, the hydrocarbon particles (e.g., the coal particles in the fine particulate coal waste) pyrolyze to form H2, carbon, and CO, which are used as reducing agents in the disclosed reduction method. The carbon produced by pyrolysis can react with water in the combustion gas to form H2 and CO. CO can react with water in the combustion gas to form H2 and CO2. In the ultra-high temperature reaction zone, H2, CO, and solid carbon particles interact with the minerals to reduce them to elemental metals.

[0076] As described above, the metal compound particles for this reduction method can include fine particulate coal waste generated from a coal preparation plant. The fine particulate coal waste includes a mixture of solid hydrocarbon particles (e.g., coal) and mineral particles.

[0077] Another raw material for the metal compound particles for this reduction method can include coal ash waste generated from a coal-fired power plant. The coal ash waste includes the ash combustion products generated from a coal-fired power plant. Since the solid coal hydrocarbons are burned, the coal ash waste has a high mineral content. There may still be some char or carbon in the coal ash waste. The carbon content is usually less than 20 mass%. Due to the complete combustion of coal in the power plant, the coal ash waste may not contain carbon or hydrocarbons. Mineral raw materials containing metal compound particles (the metal compound particles contain fine coal ash) have advantages as raw materials for this method, and the fine coal ash has solid carbon (e.g., residual coke produced by coal combustion in a coal-fired power plant) blended with the metal compound particles. In the ultra-high temperature reaction zone, the carbon particles (e.g., the char particles in the fine coal ash) can react with water in the combustion gas to form H2 and CO. CO can react with water in the combustion gas to form H2 and CO2. In the ultra-high temperature reaction zone, H2, CO, and solid carbon particles interact with the metal compound particles to reduce them to elemental metals.

[0078] H2 and / or CO and / or carbon are the reducing agents that drive the reduction of metal compound particles to elemental metals in the ultra-high temperature reaction zone. Coal, as a solid hydrocarbon, undergoes pyrolysis in the ultra-high temperature reaction zone to provide H2, CO, and / or carbon reducing agents. If the feedstock of metal compound particles is not blended with any or sufficient hydrocarbons to provide enough reducing agents to reduce all the metal compounds present, reducing agents can be added to the process. Dry fine particulate coal waste generated by a coal preparation plant with an ash content of less than about 70 wt% may be blended with sufficient fine coal particles to provide enough reducing agents to reduce the minerals.

[0079] One way to supply additional reducing agent to the process described herein for treating a feedstock of metal compound particles is to blend solid hydrocarbon particles (such as fine coal particles) with the metal compound particles before use in the process. The size d90 of the fine coal particles is typically 200 μm. In some embodiments, the size d90 of the fine coal particles is 50 μm. In another embodiment, the size d90 of the fine coal particles is 10 μm.

[0080] Another way to supply additional reducing agent to the process described herein to reduce metal compound particles is to blend solid carbon particles with the metal compound particles before use in the process. The solid carbon particles can be carbon particles, coke particles, graphite particles, biochar particles, and / or carbon black, and / or carbon black-like particles called microcarbon particles as described in U.S. Patent 11,505,464 B2. The size d90 of the carbon particles can be 50 microns. The size d90 of the carbon particles can be 10 microns. The size d90 of the carbon particles can be 1 micron. The size d90 of the carbon particles can be 0.2 micron.

[0081] Solid carbon particles or solid hydrocarbon particles blended into coal ash waste or some other source of metal compound particles that do not have enough carbon or solid hydrocarbons to reduce all the metal compound particles present to elemental metals will follow a reduction reaction path similar to that of additives. Carbon reacts with water in the combustion gas to form H2 and CO. Solid hydrocarbons pyrolyze to form H2 and solid carbon particles. The solid carbon particles react with water in the combustion gas to form H2 and CO. H2, CO, and solid carbon particles react with metal compound particles in the ultra-high temperature reaction zone to reduce the metal to its elemental form.

[0082] Another way to supply additional reducing agent to the process described herein to reduce metal compound particles is to supply a gaseous reducing agent to the ultra-high temperature reaction zone before feeding the metal compound particles into the ultra-high temperature reaction zone.

[0083] In one embodiment, the gaseous reducing agent added to the ultra-high temperature reaction zone before feeding the metal compound particles includes H2, which can be directly used as a reducing agent.

[0084] In one embodiment, the gaseous reducing agent added to the ultra-high temperature reaction zone before feeding the metal compound particles includes CO, which can be directly used as a reducing agent.

[0085] In another embodiment, the gaseous reducing agent added to the ultra-high temperature reaction zone before feeding the metal compound particles includes gaseous hydrocarbons, such as compressed natural gas (CNG). When CNG is introduced into the oxygen-deficient ultra-high temperature gaseous stream generated in the combustion chamber, CNG pyrolyzes to form H2 and solid carbon particles. The carbon can react with water in the combustion gas to form H2 and CO. In the ultra-high temperature reaction zone, H2, CO, and the solid carbon particles interact with the metal compound particles to reduce them to elemental metals.

[0086] In another embodiment, the gaseous reducing agent added to the ultra-high temperature reaction zone before feeding the metal compound particles includes a blend of H2, CO, and / or gaseous hydrocarbons.

[0087] CO can reduce the metal compound particles to form metal + CO2. H2 can reduce the metal compound particles to produce metal + H2O. Ideally, there is an excess of carbon such that whenever H2 reduces the metal compound particles to form H2O, the H2 reacts with the carbon to form CO + H2 or CO2 + H2. The removal of the excess H2 reducing agent and the H2O product establishes reaction conditions that are very favorable for the reaction system, where if the metal compound particles are maintained in the high-temperature reaction zone in the presence of H2, CO, and carbon for a sufficient length of time, very little or no metal compound remains.

[0088] The metal compound particles are reduced in the ultra-high temperature reaction zone. Example reactions that may occur are shown below. These example reactions should not be considered representative of all possible reactions. As used hereinafter, the term "MeO" is a metal oxide, the term "MeS" is a metal sulfide, the term "MeCl" is a metal chloride, and the term "MeOH" is a metal hydroxide.

[0089] MeO + H2 → Me + H2O

[0090] MeO + CO → Me + CO2

[0091] MeS + H2 → Me + H2S

[0092] MeCl + H2 → Me + HCl

[0093] MeOH + H2 → Me + H2O

[0094] In the disclosed method for the ultra - high - continuous reduction of metal compound particles, at ultra - high temperatures, individual fine to very fine metal single - compound metal particles react with a reducing agent. The reduction process is rapidly completed on a single - particle basis by pneumatic conveying in an ultra - high - temperature reaction zone. This does not require an overall process of melting bulk materials, infiltration, crushing into smaller particles, etc. The fine to very fine particle size has a very large surface area. As is well known, the larger the surface area, the faster the reaction. The fine to very fine particle size has a very small diameter and due to its extremely small penetration depth, complete reduction of metal compound particles to elemental metal can be achieved.

[0095] In the disclosed method for the ultra - high - continuous reduction of metal compound particles, carbothermal reduction reaction of metal compound particles, CO reduction of metal compound particles, and / or hydrogen reduction of metal compound particles occur. It is very likely that all three pathways occur simultaneously in the ultra - high - temperature reaction zone. Multiple reaction pathways can be used to drive the complete reduction of metal compound particles to elemental metal.

[0096] Figure 2 A general process flow diagram of the reduction method disclosed herein is shown. Ultra - high - temperature, oxygen - lean pneumatic conveying gas is generated by a burner in which fuel burns in the presence of an oxidizer, the oxidizer being >85% O2(g) <10% N2(g), where O2 is oxygen, N2 is nitrogen, % is mole % or volume %, and (g) refers to gas.

[0097] In one embodiment, O2 is about 92%. In another embodiment, O2 is about 94%. In a preferred embodiment, O2 > 99%.

[0098] One embodiment of the burner is a pulse - jet burner. A preferred embodiment is a valveless pulse burner.

[0099] One embodiment of the fuel is a gaseous fuel. One embodiment of the gaseous fuel is a hydrocarbon gas. Another embodiment of the gaseous fuel is hydrogen. A preferred embodiment of the gaseous hydrocarbon fuel is compressed natural gas. Another preferred embodiment of the gaseous hydrocarbon fuel is propane gas. Other embodiments of the fuel include solid hydrocarbons and liquid hydrocarbons.

[0100] In one embodiment, the combustion of fuel in the presence of >85% O2 produces ultra - high - temperature combustion gas >2700 °C. In another embodiment, the combustion of fuel in the presence of >90% O2 produces ultra - high - temperature combustion gas >3000 °C.

[0101] Use a pulse combustor to generate combustion gas with a low oxygen content or an oxygen-deficient environment. In one embodiment, the O2 content of the combustion gas is < 3 vol%. In another embodiment, the O2 content of the combustion gas is < 2 vol%. In yet another embodiment, the O2 content of the combustion gas is < 1 vol%. In another embodiment, the O2 content of the combustion gas is < 0.5 vol%.

[0102] In one embodiment, a gaseous reducing agent can be introduced into the ultra-high temperature reaction zone before the metal compound particles. The gaseous reducing agent can be hydrogen, which can be directly used as a reducing agent. The gaseous reducing agent can be carbon monoxide (CO), which can be directly used as a reducing agent. The gaseous reducing agent can be a gaseous hydrocarbon, such as natural gas, which will pyrolyze to form hydrogen and carbon, both of which can be used as reducing agents.

[0103] In one embodiment, a liquid reducing agent can be introduced into the ultra-high temperature zone before the metal compound particles. The liquid reducing agent can be a liquid hydrocarbon, such as diesel, biodiesel, ethanol, bioethanol, biofuel, gasoline, pentane, hexane, etc., which will pyrolyze to form hydrogen and carbon, both of which can be used as reducing agents.

[0104] Introduce the metal compound particles into the ultra-high temperature reaction zone. One method of introducing the metal compound particles is to use a screw feeder. Another method is dense-phase pneumatic conveying. Adjust the feeding rate of the metal compound particles to maintain the target temperature at the outlet of the ultra-high temperature reaction zone.

[0105] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone is about 1850 °C.

[0106] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone > 1850 °C.

[0107] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone > 2000 °C.

[0108] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone > 2500 °C.

[0109] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone > 2800 °C.

[0110] In one embodiment, the temperature at the outlet of the ultra-high temperature reaction zone > 3000 °C.

[0111] Figure 2A possible embodiment of the method is shown, where a specific temperature is set as the target after the ultra-high temperature reaction zone. In this exemplary embodiment, the metal compound particles are added to the reaction zone at a rate that produces a temperature of 1850 °C at the outlet of the ultra-high temperature reaction zone. After the ultra-high temperature reaction zone, there is a gas-vapor / liquid-solid separator that equilibrates to a temperature of about 1850 °C at the outlet of the ultra-high temperature reaction zone. In other words, the operating temperature of the gas-vapor / liquid-solid separator is in equilibrium with the temperature of the gas, vapor, liquid, and / or entrained solid particles discharged from the reaction zone.

[0112] An example of a gas-vapor / liquid-solid separator is a cyclone separator. Another example of a gas-vapor / liquid-solid separator is an electrostatic precipitator. The solids and liquids entrained in the gaseous stream can be removed from the gaseous stream by the gas-vapor / liquid-solid separator and discharged from the bottom of the gas-vapor / liquid-solid separator. Generally, the solid particles or droplets collected from the bottom of the cyclone gas-vapor / liquid-solid separator need to have a size greater than about 10 microns. The solids and liquids collected from the bottom of the gas-vapor / liquid-solid separator enter a cooled collection location. The gaseous stream continues to flow downstream to the equipment, along with any vapor, liquid, and / or solid that may be present.

[0113] After the first gas-vapor / liquid-solid separator, a cooling mechanism can be used to reduce the temperature of the gaseous stream and any entrained vapor, liquid, and / or solid to a lower temperature. In one embodiment, the cooling mechanism can be a heat exchanger. In another embodiment, the cooling mechanism can be the injection of sufficient vapor to cool the gaseous stream and the entrained vapor, liquid, and / or solid to the target temperature. In another embodiment, the cooling mechanism can be the injection of sufficient atomized water to cool the gaseous stream and the entrained vapor, liquid, and / or solid to the target temperature. In another embodiment, the cooling mechanism can be the injection of sufficient liquid nitrogen to cool the gaseous stream and the entrained vapor, liquid, and / or solid to the target temperature. One of the embodiments of the cooling mechanism can be used. Combinations of the embodiments of the cooling mechanism can be used together. In Figure 2 In the exemplary embodiment shown, the first cooling mechanism reduces the gaseous stream and the entrained vapor, liquid, and / or solid from about 1850 °C to about 1000 °C.

[0114] The 1000 °C gaseous stream and the entrained vapor, liquid, and / or solid enter a second gas-vapor / liquid-solid separator. During the cooling step, any liquid and solid deposit or condense, and those liquids and solids that meet the separation criteria of the gas-vapor / liquid-solid separator are discharged from the bottom (as described for the first gas-vapor / liquid-solid separator) to the cooled collection location.

[0115] A second cooling mechanism can be used after the second gas-vapor / liquid-solid separator to reduce the temperature of the gaseous stream and any entrained vapor, liquid, and / or solid to a lower temperature. In one embodiment, the cooling mechanism can be a heat exchanger. In another embodiment, the cooling mechanism can be injecting sufficient vapor to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. In another embodiment, the cooling mechanism can be injecting sufficient atomized water to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. In another embodiment, the cooling mechanism can be injecting sufficient liquid nitrogen to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. One of the embodiments using the cooling mechanism can be used. Combinations of the embodiments using the cooling mechanism can be used together. In Figure 2 In the exemplary embodiment shown, the second cooling mechanism reduces the temperature of the gaseous stream and entrained vapor, liquid, and / or solid from about 1000 °C to about 500 °C.

[0116] The 500 °C gaseous stream and entrained vapor, liquid, and / or solid enter the second gas-vapor / liquid-solid separator. During the cooling step, any liquid and solid deposits or condenses, and those liquids and solids that meet the separation criteria of the gas-vapor / liquid-solid separator are discharged from the bottom (as described for the first gas-vapor / liquid-solid separator) to a cooled collection location.

[0117] A third cooling mechanism can be used after the third gas-vapor / liquid-solid separator to reduce the temperature of the gaseous stream and any entrained vapor, liquid, and / or solid to a lower temperature. In one embodiment, the cooling mechanism can be a heat exchanger. In another embodiment, the cooling mechanism can be injecting sufficient vapor to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. In another embodiment, the cooling mechanism can be injecting sufficient atomized water to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. In another embodiment, the cooling mechanism can be injecting sufficient liquid nitrogen to cool the gaseous stream and entrained vapor, liquid, and / or solid to a target temperature. One of the embodiments using the cooling mechanism can be used. Combinations of the embodiments using the cooling mechanism can be used together. In Figure 2 In the exemplary embodiment shown, the third cooling mechanism reduces the temperature of the gaseous stream and entrained vapor, liquid, and / or solid from about 500 °C to <200 °C.

[0118] A gaseous stream at <200 °C and entrained vapors, liquids, and / or solids enter the gas-vapor / liquid-solid separator of the bag filter housing. During the third cooling step, any liquids and solids that deposit or condense are filtered out of the gaseous stream in the bag filter housing and discharged from the bottom of the bag filter housing to a cooled collection location.

[0119] The gaseous stream can be discharged from the facility directly through an exhaust stack or further processed through vapor and gas separation techniques. Non-limiting examples of gas separation techniques include cryogenic gas separation, pressure swing absorption, membrane absorption, vacuum pressure swing absorption, ionic liquid-based absorption, dedicated liquid chemical-based absorption, aqueous salt gas absorption, dry absorption techniques, and / or aqueous suspended solid gas absorption.

[0120] Figure 3 Shows the concentrations of target metals detected by inductively coupled plasma atomic emission spectroscopy (ICP-AES) characterization of a fine particulate coal waste sample generated by a coal preparation plant that has a flotation circuit to further clean tailings or fine particulate coal waste. The particle size d99 of this fine particulate coal waste is 200 microns and d50 is 7 microns. The ash content is approximately 80%. The sample is completely digested in strong acid. The ions in the solution are then quantified by ICP-AES. These metal elements are mainly present in mineral forms (such as oxides, aluminosilicates (clays), clay-bound ions, salts, or other mineral compounds), rather than pure elemental metals. The concentrations of the valuable metals listed in the fine particulate coal waste sample are shown by the blue bars and correspond to the ppm values on the left y-axis. Due to the excessively high concentrations of aluminum, iron, and silicon, the concentrations of the remaining metals cannot be seen in Figure 3 The melting points and boiling points of the metals are also shown by horizontal lines and vertical lines connecting the lines and correspond to the y-axis on the right.

[0121] Figure 3 The data in are shown by way of example, indicating that multiple metals are present in the mineral composition of the fine particulate coal waste generated by the coal preparation plant. It should be understood that Figure 3 (and Figure 4 , Figure 5 and Figure 6 ) the metals and metal concentrations present are given only as examples and are not intended to represent that the concentrations of the fine particulate coal waste or fine particulate coal ash at other locations in the reservoir or of any other samples of fine particulate coal waste or fine particulate coal ash in other reservoirs necessarily have the same characteristics. The metals and metal concentrations present in a given sample can vary in the fine particulate coal waste in the reservoir because the fine particulate coal waste in the reservoir represents the mining of different locations and coal seams over the years. Similarly, the metals present and the metal concentrations present can vary from one reservoir to another because these sites are generated by different mines or different mine depths.

[0122] It should also be understood that the metals present and their concentrations can vary within the fine particulate coal ash storage ponds and from one coal ash storage pond to another because during the accumulation of the fine particulate waste in a given coal ash storage pond, the coal from different mines may have been burned at different times and because the coal from different mines may have burned to produce different coal ash storage ponds.

[0123] Figure 4 Shows the concentrations of target metals detected by ICP - AES characterization of samples of fine particulate coal waste produced by a coal preparation plant that has a flotation circuit to further clean the tailings or fine particulate coal waste. The melting and boiling points of the metals are also represented by horizontal lines and vertical lines connecting them. Compared with Figure 3 the concentrations of aluminum, iron, and silicon have been removed from the dataset to show the concentrations of other metals present. The maximum ppm value on the left y - axis is 450 ppm. It is clear that other metal elements are present in the fine particulate waste samples (metal compound particles), but at much lower concentrations.

[0124] Figure 5 and Figure 6 shows the concentrations of a selected group of metals detected by ICP - AES characterization from the dataset shown in Figure 3 and Figure 4 The melting and boiling points of the metals are also represented by horizontal lines and vertical lines connecting the short lines. In Figure 6 the concentrations of aluminum, iron, and silicon have been removed from the dataset to show the concentrations of other metals present. Figure 5 and Figure 6 dashed lines are also added in to represent the temperatures of the first gas - vapor / liquid - solid separator, the second gas - vapor / liquid - solid separator, and the third gas - vapor / liquid - solid separator in Figure 2 The gas - vapor / liquid - solid separators are equilibrated to approximately the temperature of the incoming gaseous stream.

[0125] Referring to Figure 2 as an embodiment of the disclosed reduction method, and using the metals shown in Figure 5 and Figure 6 as example metals containing metal compound particles, metal compound particles are added at a certain rate through a feeder such that the temperature at the outlet of the ultra - high temperature reaction zone is approximately 1850 °C. Figure 5 and Figure 6 have long dashed lines representing a temperature of 1850 °C. The boiling points of barium, cesium, and rubidium are below 1850 °C. These three metals will be in the gaseous phase at 1850 °C. The melting points of boron, rhodium, vanadium, and potentially zirconium are all above 1850 °C. These metals will be in the solid phase at 1850 °C. The remaining metals will be in the liquid phase.

[0126] A gaseous stream containing solid, liquid, and vaporized metals exits the high-temperature reaction zone and enters a first gas-vapor / liquid-solid separator that is equilibrated to approximately 1850 °C. A non-limiting example of such a device is a cyclone separator. Liquid and solid metals are removed from the gaseous stream and discharged from the bottom of the cyclone separator. The cyclone separator can be designed to have different target sizes for discharge from the bottom of the cyclone separator. A common size is approximately 10 microns, although smaller sizes (e.g., 2 to 3 microns) are also possible. Solid elemental particles and elemental metal droplets larger than the cut-off size exit the bottom of the cyclone separator and reach a cooled collection location that will include aluminum, boron, iron, neodymium, palladium, rhodium, scandium, silicon, vanadium, and zirconium if aluminum, boron, iron, neodymium, palladium, rhodium, scandium, silicon, vanadium, and zirconium are present in the metal compound particles. Unreacted carbon and mineral particles larger than the cut-off size will also be discharged from the bottom of the first gas-vapor / liquid-solid separator. Solids and liquids smaller than the cut-off size are discharged from the top of the gas-vapor / liquid-solid separator. Vaporized metals exit the top of the cyclone separator with the hot gaseous stream, which will include boron, cesium, and rubidium if boron, cesium, and rubidium are present in the metal compound particles. In this example, Figure 5 and Figure 6 the metals in are used as example metals containing metal compound particles, and all elemental metals present in the metal compound particles added to the ultra-high temperature reaction zone (which are reduced to elemental metals in the ultra-high temperature reaction zone) will be discharged from the bottom of the cyclone separator, except that barium, cesium, and rubidium will be in the gas phase. The material discharged from the bottom of the cyclone separator can be cooled as a whole to produce a blended metal ingot. If no alloy is formed between the elemental metals present, further separation can be based on melting temperature and density.

[0127] The hot gaseous stream containing barium, cesium, and rubidium continues through the system. The hot gaseous stream is cooled by a cooling mechanism to reduce the temperature of the hot gaseous stream below the boiling point of barium (e.g., 1000 °C), as shown by the dash-dot-dot line in Figure 5 and Figure 6 . Barium is now in the liquid phase. The gaseous stream passes through a second gas-vapor / liquid-solid separator. Liquid barium is discharged from the bottom of the separator. It can be cooled to form a barium ingot. Vaporized metals exit the top of the cyclone separator with the hot gaseous stream. In this example, cesium and rubidium exit the top of the cyclone separator in the vapor phase with the hot gaseous stream. Solids and liquids smaller than the cut-off size are discharged from the top of the gas-vapor / liquid-solid separator.

[0128] The hot gaseous stream containing cesium and rubidium continues to pass through the system. The hot gaseous stream is cooled by a cooling mechanism, reducing its temperature below the boiling points of cesium and rubidium (e.g., 500 °C as indicated by the dash). Cesium and rubidium are now in the liquid phase. The gaseous stream passes through a third gas-vapor / liquid-solid separator. Liquid cesium and rubidium are discharged from the bottom of the separator.

[0129] The liquid cesium and rubidium discharged from the bottom of the gas-vapor / liquid-solid separator can be cooled to form a blended metal ingot. Optionally, if no alloy is formed between the metals, further separation can be based on melting temperature and density. The melting temperature of rubidium is 40 °C and that of cesium is 29 °C. This material can be cooled to 30 °C. Rubidium will be in the solid state while cesium will remain in the liquid state. The two metals can be separated as they are in different phases.

[0130] At this point, there should be no entrained metal compound particles in the hot gaseous stream, but depending on the content and nature of the reducing agent present, there may be some unreacted metal compound particles, depending on whether there is sufficient reducing agent to ensure the conversion of metal compound particles to elemental metal through the necessary reduction pathways. Then, the process gaseous stream can be sent to downstream processing equipment, which can include another cooling mechanism to cool the gaseous stream to below 200 °C, causing the process gas and any remaining vapors, liquids, and / or solids to enter a bag filter chamber to separate solid particles that may remain in the gaseous stream. The possible solids are very fine carbon particles, whose properties may be similar to carbon black. There may be very fine coke. There may be very fine graphite particles.

[0131] After finally removing the solids in the bag filter chamber, the process gas can be further processed to separate the possible gases and vapors. Examples of valuable gases that may be present are H2, CO2, NH3, H2S, NO x 、SO x and water. Cooling the gas can further condense the water vapor that may be present in the gaseous stream. Methods such as pressure swing absorption and / or cryogenic gas capture separation can be used to separate the possible gases. The unreacted H2 collected can be used as fuel for the process. Another option is to inject H2 as a reducing agent in the process. H2 can also be sold on the market.

[0132] This example is for illustrative purposes only and should not be considered limiting. Depending on the metals present and the combination of their melting and boiling points, more or fewer gas-vapor / liquid-solid separator steps can be used in the process at different temperatures to meet the predetermined separation goals.

[0133] In the ultra-high temperature reaction zone at a ratio higher than Figure 2Operating the reduction process at a temperature higher than about 1850°C in the exemplary embodiments shown may be advantageous. One advantage of operating at a temperature higher than 1850°C is to drive the complete reduction of the metal compound particle feedstock into elemental metal. One advantage of operating at a temperature higher than 1850°C is to keep the target elemental metal in a gaseous state. One advantage of operating at a temperature higher than 1850°C is to keep the target elemental metal in a liquid state.

[0134] In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone is about 2000°C. In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone is about 2500°C. In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone is about 3000°C.

[0135] In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone > 2000°C. In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone > 2500°C. In one embodiment, the feed rate of the mineral-containing feedstock is controlled such that the outlet temperature of the ultra-high temperature reaction zone > 3000°C.

[0136] It may be advantageous to rapidly reduce the temperature after the ultra-high temperature reaction zone. At temperatures lower than the ultra-high temperature reaction zone, it is possible and even more likely that reverse reactions or side reactions occur among the gases, liquids, and solids present in the gaseous stream, generating substances other than elemental metal. One advantage of rapidly reducing the temperature after the ultra-high temperature reaction zone is to avoid the temperatures at which reverse reactions and side reactions may occur.

[0137] Figure 7 To show a comprehensive flow chart of all non-limiting iterations, combinations, and variations of the disclosed invention as a variation of Figure 2 The hollow triangle at the end of the ultra-high temperature reaction zone represents a nozzle that initiates adiabatic cooling. As described in the previous paragraphs, embodiments of the method have a feed rate such that the outlet temperature of the ultra-high temperature reaction zone is far higher than 1850°C, even higher than 3000°C. In this case, cooling means may be required before the first gas-vapor / liquid-solid separator to achieve the first temperature of the first gas-vapor / liquid-solid separator. If cooling is required between the ultra-high temperature zone and the first gas-vapor / liquid-solid separator, then adiabatic cooling is a preferred embodiment.

[0138] If Figure 7The embodiments of the method shown are run at a feed rate such that the outlet temperature of the ultra-high temperature reaction zone entering the adiabatic cooling nozzle is 3000 °C, then a pressure of approximately 215 pounds per square inch will be required upstream of the nozzle, driving almost instantaneous cooling after the adiabatic cooling nozzle so as to enter the first gas-vapor / liquid-solid separator at approximately 1500 °C.

[0139] Figure 7 The exemplary embodiments in show that the temperature of the second gas-vapor / liquid-solid separator is 1200 °C, the temperature of the third gas-vapor / liquid-solid separator is 700 °C, and the temperature of the bag filter gas-vapor / liquid-solid separator is 45 °C. Figure 2 and Figure 7 These temperatures of the gas-vapor / liquid-solid separators in and do not represent the exact operating temperatures that must be used. Figure 7 Different temperatures are shown in to illustrate that the process can be designed according to different temperature targets. The process design will be based on the boiling point / condensation point and melting point / freezing point of the elemental metal produced from the target metal compound particle feedstock. The ability to select the temperature based on the material properties of the elemental metal in the gaseous stream is crucial, which enables the separation of the elemental metal present in the gaseous stream based on the material properties. This separation will result in the concentration of the elemental metal at different collection locations according to its material characteristics.

[0140] Figure 2 and Figure 7 The embodiments in and both show three gas-vapor / liquid-solid separators before the bag filter gas-vapor / liquid-solid separator. More or fewer gas-vapor / liquid-solid separators can be used based on the material properties of the elemental metal in the gaseous stream and the number of collection concentration separations required in the method.

[0141] Embodiment

[0142] The following lists various embodiments. It should be understood that, within the scope of the present invention, the embodiments listed below can be combined with all aspects and other embodiments.

[0143] Embodiment 1. A continuous method for converting metal compound particles into a mixture of elemental metals, comprising: introducing metal compound particles and a reducing agent into an ultra-high temperature reaction zone, wherein the particle size d90 of the metal compound particles is 500 μm, and wherein the temperature of the ultra-high temperature reaction zone is higher than 2700 °C and the oxygen content is less than 3 vol%, wherein the residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 1 minute, sufficient to mix and react with the reducing agent so as to reduce the metal compound particles to form a mixture of elemental metals; removing from the ultra-high temperature reaction zone gases, vapors, liquids, and / or entrained solid particles containing the mixture of elemental metals; and separating the mixture of elemental metals from the gases, vapors, liquids, and / or entrained solid particles based on the different sizes and densities of one or more elemental metals and the remaining mixture of elemental metals, and concentrating one or more elemental metals from the mixture of elemental metals in one or more separation zones.

[0144] Embodiment 2. The method according to Embodiment 1, wherein the d90 particle size of the metal compound particles is less than 200 μm.

[0145] Embodiment 3. The method according to Embodiment 1, wherein the d90 particle size of the metal compound particles is less than 100 μm.

[0146] Embodiment 4. The method according to Embodiment 1, wherein the d90 particle size of the metal compound particles is less than 50 μm.

[0147] Embodiment 5. The method according to any one of the preceding embodiments, wherein the metal compound particles comprise one or more rare earth metals.

[0148] Embodiment 6. The method according to any one of Embodiments 1 to 4, wherein the metal compound particles comprise one or more transition metals.

[0149] Embodiment 7. The method according to any one of the preceding embodiments, wherein the oxygen content of the ultra-high temperature reaction zone is less than 1 vol%.

[0150] Embodiment 8. The method according to any one of the preceding embodiments, wherein combustion gases discharged from a pulse combustor are introduced into the ultra-high temperature reaction zone.

[0151] Embodiment 9. The method according to any one of the preceding embodiments, wherein the reducing agent comprises carbon particles.

[0152] Embodiment 10. The method according to Embodiment 9, wherein the particle size d90 of the carbon particles is 10 μm.

[0153] Embodiment 11. The method according to Embodiment 9, wherein the particle size d90 of the carbon particles is 5 μm.

[0154] Embodiment 12. The method according to Embodiment 9, wherein the particle size d90 of the carbon particles is 1 μm.

[0155] Embodiment 13. The method according to Embodiment 9, wherein the particle size d50 of the carbon particles is 100 nm.

[0156] Embodiment 14. The method according to any one of Embodiments 1 to 8, wherein the reducing agent includes hydrogen.

[0157] Embodiment 15. The method according to any one of Embodiments 1 to 8, wherein the reducing agent includes carbon monoxide gas.

[0158] Embodiment 16. The method according to any one of Embodiments 1 to 8, wherein the reducing agent includes hydrocarbons.

[0159] Embodiment 17. The method according to Embodiment 16, wherein the hydrocarbons include coal.

[0160] Embodiment 18. The method according to Embodiment 16, wherein the hydrocarbons include natural gas.

[0161] Embodiment 19. The method according to any one of Embodiments 1 to 8, wherein the reducing agent includes at least two reducing agents among hydrogen, carbon monoxide gas, and natural gas.

[0162] Embodiment 20. The method according to any one of the foregoing embodiments, wherein the metal compound particles include fine coal waste generated in a mine or a mining process.

[0163] Embodiment 21. The method according to any one of Embodiments 1 to 19, wherein the metal compound particles include coal ash waste.

[0164] Embodiment 22. The method according to any one of the foregoing embodiments, wherein the residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 50 seconds, 40 seconds, 30 seconds, 25 seconds, 20 seconds, 18 seconds, 16 seconds, 14 seconds, 12 seconds, 10 seconds, 9 seconds, 8 seconds, 7 seconds, 6 seconds, 5 seconds, 4 seconds, 3 seconds, 2 seconds, or 1 second.

[0165] Embodiment 23. A method for separating one or more elemental metals from an elemental metal mixture produced by ultra-high temperature reduction of metal compound particles, wherein the temperature of the elemental metal mixture is higher than 1850 °C, the method includes placing the elemental metal mixture in a first cyclone separator operating at a first cyclone separator temperature, and separating one or more elemental metals from the remaining elemental metal mixture based on the different sizes and / or densities of the one or more elemental metals and the remaining elemental metal mixture.

[0166] Embodiment 24. The method according to embodiment 23, the method comprising placing the remaining elemental metal mixture within a second cyclone separator operating at a second cyclone separator temperature and separating one or more other elemental metals from the remaining other elemental metal mixture based on the different sizes and / or densities of the one or more other elemental metals and the remaining other elemental metal mixture.

[0167] Embodiment 25. The method according to embodiment 24, the method comprising placing the remaining other elemental metal mixture within one or more serially connected subsequent cyclone separators and operating at different cyclone separator temperatures, and separating one or more subsequent elemental metals from the remaining subsequent elemental metal mixture based on the different sizes and / or densities of the one or more subsequent elemental metals and the remaining subsequent elemental metal mixture.

[0168] Embodiment 26. The method according to embodiment 24, wherein a temperature reduction of the remaining elemental metal mixture occurs between the first cyclone separator and the second cyclone separator.

[0169] Embodiment 27. The method according to embodiment 24, wherein the temperature reduction is achieved by a heat exchanger.

[0170] Embodiment 28. The method according to embodiment 24, wherein the temperature reduction is achieved by introducing a spray of liquid nitrogen.

[0171] Embodiment 29. The method according to embodiment 24, wherein the temperature reduction is achieved by introducing a spray of water.

[0172] Embodiment 30. The method according to embodiment 23, wherein the first cyclone separator temperature is balanced with the temperature of the incoming elemental metal mixture.

[0173] Embodiment 31. The method according to embodiment 23, wherein a nozzle is provided between the ultra-high temperature reaction zone and the first cyclone separator operating at the first cyclone separator temperature.

[0174] Embodiment 32. A continuous process for converting metal compound particles into a mixture of elemental metals, comprising: burning a fuel with >85% O2 in a burner to produce an ultra-high temperature process gas that provides heat and temperature to an ultra-high temperature reaction zone, and wherein the initial temperature of the ultra-high temperature reaction zone is higher than 2700 °C and the oxygen content after combustion is less than 3 vol%; at the inlet of the ultra-high temperature reaction zone, introducing metal compound particles into the ultra-high temperature process gas, wherein the metal compound particles are pneumatically conveyed through the ultra-high temperature reaction zone to a downstream device, wherein the particle size d90 of the metal compound particles is 500 μm, wherein the residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 1 minute, sufficient to mix and react with a reducing agent in the ultra-high temperature reaction zone to reduce the metal compound particles to form a mixture of elemental metals; allowing the process gas to leave the ultra-high temperature reaction zone at a temperature higher than 1850 °C, wherein the temperature of the process gas leaving the ultra-high temperature reaction zone is controlled by the rate of addition of dry (<0.5 mass% moisture) metal compound particles to the ultra-high temperature reaction zone, and wherein the process gas leaves the ultra-high temperature reaction zone together with the product produced by continuously ultra-high temperature reducing the metal compound particles in pneumatic conveying, and wherein the product comprises a mixture of elemental metals consisting of gases, vapors, liquids, and / or entrained solid particles; and separating the mixture of elemental metals from the process gas, vapors, liquids, and / or entrained solid particles, and concentrating one or more elemental metals from the mixture of elemental metals in one or more gas-vapor / liquid-solid separators based on the different sizes and densities of the solid particles and / or droplets present at the temperature when the process gas and the pneumatic conveying material pass through one or more gas-vapor / liquid-solid separators, wherein in the gas-vapor / liquid-solid separator, the solids and / or droplets separated from the process gas stream are discharged from the bottom to a cooled collection location, and the process gas continues to flow downstream to a downstream device together with the new composition of elemental metals formed by the separation step, and the downstream device may include one or more gas-vapor / liquid-solid separators at a lower temperature, and further separating the solid particles and / or droplets in each subsequent gas-vapor / liquid-solid separator based on the different sizes and densities of the solid particles and / or droplets present at the temperature when the process gas and the pneumatic conveying material pass through the subsequent gas-vapor / liquid-solid separator, and wherein the final separation step may be a bag filter gas-vapor / liquid-solid separator at a temperature below 200 °C.

[0175] Embodiment 33. The method according to Embodiment 32, wherein the reducing agent is formed by pyrolysis of hydrocarbon particles (such as coal) mixed with the metal compound particles.

[0176] Embodiment 34. The method according to Embodiment 32, wherein the reducing agent is gaseous and is introduced into the ultra-high temperature reaction zone before adding the dry (moisture < 0.5 mass%) metal compound particles into the ultra-high temperature reaction zone.

[0177] Embodiment 35. The method according to Embodiment 34, wherein the reducing agent is H2 gas.

[0178] Embodiment 36. The method according to Embodiment 34, wherein the reducing agent is CO gas.

[0179] Embodiment 37. The method according to Embodiment 34, wherein the reducing agent is natural gas.

[0180] The described embodiments and examples should be considered illustrative only and not restrictive in every respect. Thus, the scope of the present invention is indicated by the appended claims rather than by the preceding description. All variations within the meaning and scope of the equivalents of the claims are included within the scope of the claims.

Claims

1. A continuous method for converting metal compound particles into a mixture of elemental metals, comprising: introducing the metal compound particles and a reducing agent into an ultra-high temperature reaction zone, wherein the d90 particle size of the metal compound particles is 500 μm, and wherein the temperature of the ultra-high temperature reaction zone is higher than 2700 °C and the oxygen content is less than 3 vol%, wherein the residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 1 minute, sufficient to mix and react with the reducing agent, thereby reducing the metal compound particles to form the mixture of elemental metals; removing from the ultra-high temperature reaction zone gases, vapors, liquids, and / or entrained solid particles containing the mixture of elemental metals; and separating the mixture of elemental metals from the gases, vapors, liquids, and / or entrained solid particles based on the different sizes and densities of one or more elemental metals and the remaining mixture of elemental metals, and concentrating one or more elemental metals from the mixture of elemental metals in one or more separation zones.

2. The method according to claim 1, wherein the d90 particle size of the metal compound particles is less than 200 μm.

3. The method according to claim 1, wherein the d90 particle size of the metal compound particles is less than 100 μm.

4. The method according to claim 1, wherein the d90 particle size of the metal compound particles is less than 50 μm.

5. The method according to claim 1, wherein the metal compound particles comprise one or more rare earth metals.

6. The method according to claim 1, wherein the metal compound particles comprise one or more transition metals.

7. The method according to claim 1, wherein the oxygen content of the ultra-high temperature reaction zone is less than 1 vol%.

8. The method according to claim 1, wherein combustion gases discharged from a pulse combustor are introduced into the ultra-high temperature reaction zone.

9. The method according to claim 1, wherein the reducing agent comprises carbon particles.

10. The method according to claim 9, wherein the d90 particle size of the carbon particles is 10 μm.

11. The method according to claim 9, wherein the d90 particle size of the carbon particles is 5 μm.

12. The method according to claim 9, wherein the d90 particle size of the carbon particles is 1 μm.

13. The method according to claim 9, wherein the d50 particle size of the carbon particles is 100 nm.

14. The method according to claim 1, wherein the reducing agent comprises hydrogen gas.

15. The method according to claim 1, wherein the reducing agent comprises carbon monoxide gas.

16. The method according to claim 1, wherein the reducing agent comprises a hydrocarbon.

17. The method according to claim 16, wherein the hydrocarbon comprises coal.

18. The method according to claim 16, wherein the hydrocarbon comprises natural gas.

19. The method according to claim 1, wherein the reducing agent comprises at least two reducing agents of hydrogen gas, carbon monoxide gas, or natural gas.

20. The method according to claim 1, wherein the metal compound particles comprise fine particulate coal waste generated in a mine or mining process.

21. The method according to claim 1, wherein the metal compound particles comprise coal ash waste.

22. The method according to claim 1, wherein the residence time of the metal compound particles in the ultra-high temperature reaction zone is less than 10 seconds.

23. A method for separating one or more elemental metals from an elemental metal mixture produced by ultra-high temperature reduction of metal compound particles, wherein the temperature of the elemental metal mixture is higher than 1850 °C, the method comprising placing the elemental metal mixture within a first cyclone separator operating at a first cyclone separator temperature and separating one or more elemental metals from the remaining elemental metal mixture based on the different sizes and / or densities of the one or more elemental metals and the remaining elemental metal mixture.

24. The method according to claim 23, wherein the method comprises placing the remaining elemental metal mixture within a second cyclone separator operating at a second cyclone separator temperature and separating one or more other elemental metals from the other remaining elemental metal mixture based on the different sizes and / or densities of the one or more other elemental metals and the other remaining elemental metal mixture.

25. The method according to claim 24, wherein the method comprises placing the other remaining elemental metal mixture within one or more serially connected subsequent cyclone separators and operating at different cyclone separator temperatures, and separating one or more subsequent elemental metals from the subsequent remaining elemental metal mixture based on the different sizes and / or densities of the one or more subsequent elemental metals and the subsequent remaining elemental metal mixture.

26. The method according to claim 24, wherein a temperature reduction of the remaining elemental metal mixture occurs between the first cyclone separator and the second cyclone separator.

27. The method according to claim 24, wherein the temperature reduction is achieved by a heat exchanger.

28. The method according to claim 24, wherein the temperature reduction is achieved by introducing a spray of liquid nitrogen.

29. The method according to claim 24, wherein the temperature reduction is achieved by introducing a spray of water.

30. The method according to claim 23, wherein the first cyclone separator temperature is in equilibrium with the temperature of the incoming elemental metal mixture.

31. The method according to claim 23, wherein a nozzle is provided between the ultra-high temperature reaction zone and the first cyclone separator operating at the first cyclone separator temperature.

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