Flash joule heating reactors and methods

Abstract

The embodiments disclosed herein relate to methods and systems for efficient Joule heating of powder materials, and in particular, Joule heating of a powder feedstock that is mixed while the powder is Joule heated. The systems and methods of this invention include the design of sealed and open-to-atmosphere Joule heating reactors for scaled production of materials, including graphene, graphite, carbon nanotubes, silicon carbide, and hydrogen gas, including reactors operating in continuous mode of production.

Description

Flash Joule Heating Reactors and MethodsThis application claims the benefit of U.S. Provisional Patent Application Serial No. 63 / 691,691, which was filed on September 6, 2024.Field of the Invention

[0001] This invention relates to reactor systems and methods for producing materials with the use of Joule heating, and in particular sealed and open-to-atmosphere Joule heating reactors for scaled production of materials, including for example graphene, graphite, carbon nanotubes, silicon carbide, and hydrogen gas, including reactors operating in continuous mode of production.Description of the Related Art

[0002] A flash joule heating synthesis of graphene with a quartz tube as the reactor is disclosed in PCT International Publication No. WO 2020 / 051000 to Tour et al., where electrically conductive carbon material is resistively heated to convert the carbon into graphene. In this prior art disclosure, carbon material is compressed into a quartz tube reactor, sealed with two electrode plugs, and wherein multiple voltage pulses are applied to rapidly heat the confined carbon and convert it into turbostratic graphene.

[0003] Relevant art includes Provisional Patent Application US 63 / 629,967, HYDROCARBON PYROLYSIS VIA JOULE HEATING OF POWDER, by Mancevski, having an application date of October 11, 2023, which is herein incorporated by reference in its entirety, and in Provisional Patent Application US 63 / 629,975, INDIRECT HYDROCARBON PYROLYSIS WITH JOULE HEATING OF POWDER, by Mancevski, having an application date of October 17, 2023, which is herein incorporated by reference in its entirety.

[0004] A relevant art shown in Figure 1A, discloses a reactor (that can be sealed) for flash Joule heating, as disclosed by Mancevski (US 63 / 629,967). This reactor is capable of large-scale Joule heating of gasses and powders. This prior art discloses an electrically conductive bucket reactor containing powder material, wherein the bucket operates as one of the electrodes, and having a rotating / moving (with respect to the bucket reactor) electrode submerged into thepowder material configured to mix the powder material and to Joule heat the powder material by enabling electrical current flow from the rotating / moving electrode to the bucket reactor electrode, wherein the electrical current Joule heats the mixed powder material to change the material's properties.

[0005] An open-air rotating ceramic pot reactor with stationary electrode pair for flash Joule heating of powders is shown in Figure IB and disclosed by Eddy et al. (ACS Nano 2024, 18, 50, 34207-34218). This prior art discloses rotating ceramic pot reactor, containing powder material, and having fixed (with respect to the bucket reactor) set of two electrodes submerged into the powder material, wherein the set of electrodes may mix the powder material when the ceramic pot reactor is rotating, and to Joule heat the powder material to change the material's properties. This disclosure does not teach reactors with an electrically conductive reactor where the current path is between an electrode submerged into a powder material and an electrically conductive reactor. This prior art disclosure also does not teach flow through tube reactors as disclosed here.Another relevant art disclosed by Mancevski (PCT / US25 / 16228) discloses methods for flash Joule heating capable of large-scale Joule heating of powders, wherein the feedstock (starting material before the Joule heating process) is mixed / moved inside the reactor before, while, and after the Joule heating of the feedstock to improve the uniformity and quality of the resulting processed material whose properties have changed because of the Joule heating process. Prior art includes Provisional Patent Application US 63 / 554,802, GRAPHITE SYNTHESIS VIA JOULE HEATING OF POWDERS, by Mancevski, having an application date of February 16, 2024, which is herein incorporated by reference in its entirety.Summary Of The Invention

[0006] The current invention comprises

[0007] One embodiment of the current invention is a method for.

[0008] Another exemplary embodiment of the current invention is a method for.

[0009] Another exemplary embodiment of the current invention is a method for

[0010] Another exemplary embodiment of the current invention is a system for joule heating powders, comprising:

[0011] The systems according to the present invention can comprise many different features as described below. These and other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings which illustrate by way of example the features of the invention.Brief Description of the Drawings

[0012] The drawings included herewith illustrate various examples of articles, methods, and systems of the present specification.

[0013] FIG. 1A shows a prior art sealed graphite-bucket reactor with a rotating oval electrode for Joule heating of gases and powders.

[0014] FIG. IB shows a prior art open-air rotating ceramic pot reactor with a stationary electrode pair for flash Joule heating of powders.

[0015] FIG. 2 shows an example of sealed rotating graphite-bucket reactor with a stationary electrode pair for flash Joule heating batch processes. (A) side view. B (top view).

[0016] FIG. 3 shows an example of a sealed rotating graphite-bucket reactor / counter- electrode with a mixing electrode for flash Joule heating batch processes. (A) side view. B (top view).

[0017] FIG. 4 shows an example of a rocking-motion tilted ceramic-tube reactor with a stationary electrode pair for continuous flash Joule heating processes. (A) side view. B (cross view).

[0018] FIG. 5 shows an example of a rocking-motion tilted graphite-tube reactor and electrode with stationary oval electrode for continuous flash Joule heating processes. (A) side view. B (cross view).

[0019] FIG. 5C shows an example of a rocking-motion tilted graphite-tube reactor and electrode with a stationary flared electrode for continuous flash Joule heating processes (cross view)

[0020] FIG. 6 shows an example of a continuous process sealed reactor for flash Joule heating with additional assemblies shown. (A) side view. B (cross view).

[0021] FIG. 7 shows an example of a reactor with a graphite-box counter-electrode and a longitudinal electrode for flash Joule heating batch processes. (A) cross view. B (side view).

[0022] FIG. 8 shows an example of a reactor with a graphite-box counter-electrode and a longitudinal rod electrode for continuous flash Joule heating processes. (A) cross view. B (side view).

[0023] FIG. 9 shows an example of a reactor with a graphite-box counter-electrode and a rotating longitudinal oval electrode for continuous flash Joule heating processes. (A) cross view. B (side view).

[0024] FIG. 10 shows an example of a reactor with a graphite-box counter-electrode and a rotating paddle longitudinal electrode for continuous flash Joule heating processes. (A) cross view. B (side view).

[0025] FIG. 11 shows a prior art flowchart for graphene synthesis via Joule heating.

[0026] FIG. 12 shows a flowchart of flash Joule heating processes of secondary powders.

[0027] FIG. 13 shows a flowchart of continuous Joule heating processes of secondary powders.

[0028] FIG. 14A shows a prior art flowchart for flash Joule heating processes for Lithium recovery.

[0029] FIG. 14B shows a prior art flowchart for flash Joule heating processes for Lithium separation.

[0030] FIG. 15A shows a flowchart of flash Joule heating processes for Lithium extraction / separation with chlorination powder.

[0031] FIG. 15B shows a flowchart of flash Joule heating processes for Lithium extraction / separation with chlorine gas.

[0032] FIG. 16A shows an example of a prototype rotating graphite-bucket reactor with stationary electrode pair for Joule heating.

[0033] FIG. 16B shows an example of a prototype rotating clay-bucket reactor with thermal isolation for Joule heating.Detailed Description

[0034] Various systems or processes will be described below to provide examples of the claimed embodiments. No embodiment or embodiments described below are intended to limit any claimed embodiment, and any claimed embodiment may cover processes or system in addition to or that differ from those specifically described. The claimed embodiments are not limited to systems or processes having all of the features of any one system or process described, or to features common to some or all of the systems described.

[0035] The teaching of this disclosure enables the fabrication of all carbon nanostructures, including amorphous carbon, crystalline carbon, nanostructured sp2 carbon forms, such as graphene, fullerene, and carbon nanotubes, stacked graphene such as graphite, and their combinations and variations.

[0036] Graphene and graphite consists of sp2 carbon hexagonal networks of carbon atoms with covalent bonding between C atoms within a layer, and a weak van der Waals interaction between adjacent layers. Graphite is defined as 3-D layered material formed by stacking more than 10 single-layer graphene layers of 2-D graphene.

[0037] The term "graphene" refers to a material which is a one-atom-thick planar sheet of sp2-bonded carbon atoms that are densely packed in a honeycomb crystal lattice, and, further, contains an intact ring structure of carbon atoms and aromatic bonds throughout at least a majority of the interior sheet and lacks significant oxidation modification of the carbon atoms. Graphene has a predominantly crystalline structure and its quality is measured by its degree of crystallinity. The term "a graphene monolayer" refers to graphene that is a single layer ofgraphene. The term "very few layer graphene" refers to graphene that is between 1 to 3 layers of graphene. The term "few layer graphene" refers to graphene that is between 2 to 5 layers of graphene. The term "multilayer graphene" refers to graphene that is between 2 to 10 layers of graphene. Monolayer to multilayer graphene has typical lateral sizes from sub-lOOnm to few microns. The term "graphite" refers to a structure that has more than 10 layers of graphene. Graphite has typical lateral sizes from 10s of nanometers to 10s of microns.

[0038] The term "Graphite" refers to a carbon structure that has more than 10 layers of graphene in an ordered stacking arrangement. Graphite may have AB, also known as Bernal, or ABC, also known as rhombohedral, stacking arrangement.

[0039] Both graphene and graphite may be ordered (stacked) or disordered (turbostratic), referring to the order of adjacent layers in the structure. While this paragraph discusses the difference between graphene and graphite, and stacked and disordered carbon arrangements, it does not limit any embodiment disclosed herein to a specific arrangement.

[0040] Embodiments of the present invention offer solutions that make it possible to synthesize and produce graphite material with Joule heating from a variety of carbon containing materials, which is efficient and that includes mixing of the carbon containing material within a reactor as it undergoes Joule heating. Furthermore, the present invention offers solutions to efficiently increase (improve) the crystallinity (the crystal structure) of a material, for example carbon or silicon, with Joule heating with a precise control over the degree of crystallinity improvements. Although the degree of crystallinity improvements in a material is continuous, for the purposes of describing this invention the degree of crystallinity improvements may be qualitatively described as partial, substantial, and full material crystallization. Additionally, the present invention offers efficient Joule heating based solutions to convert plastics, and polymers in general, into amorphous carbon (plastics char) that can be further converted into carbon with any degree of crystallinity.

[0041] The conversion of a carbon material into more crystalline carbon material is known as graphitization. Carbon graphitization refers to the process of heating a carbon material to high temperatures, causing its carbon atoms to rearrange into a more ordered, crystallinestructure, thus enhancing its crystalline level. The degree of graphitization of a material is continuous, but may be described as partial, substantial, and full carbon graphitization for ease of reference.

[0042] The conversion of a silicon-based material into more crystalline form of the silicon material refers to the process of enhancing the ordered, crystalline structure within a silicon material, where silicon atoms are arranged in a consistent lattice pattern. The term silicon material refers to silicon, silica, or any silicon compound.

[0043] Thew current disclosure also employs methods of powder mixing Joule heating processes as well as reactors suitable for powder mixing Joule heating. The term mixing (and moving) the powder material is defined as moving the grains of the feedstock powder (whether they are electrically conductive or not) inside a process reactor as to make a more uniform volume of powder, before, during, and / or after the Joule heating. Mixing the powder means that grains comprising the powder are moved with respect to each other to randomize their relative position with respect to each other, or their absolute position within the reactor. The result of mixing the feedstock powder in the reactor so as to average the exposure of energy on the feedstock and to do it more uniformly, resulting in more controllable conversion of the material. The powder mixing can be conducted continuously during the Joule heating process or intermittently after some energy is delivered. One measure of product uniformity and quality synthesized by Joule heating is the Raman signature of the powder, for example the location, shape, sharpness, and intensity of the Raman D, G, and 2D peaks. Another measure of product uniformity and quality synthesized by Joule heating is the XRD signature of the powder, for example the location, shape, sharpness, and intensity of the XRD peaks.

[0044] In the art of heating processes, the term Joule (resistive) heating includes resistive heating of conventional heating element devices such as metal wire filaments, film elements, carbon paper, carbon cloth, or other bulk heating elements, whose shape does not change during the process, for example, wire remains wire during the resistive heating, carbon paper remains as carbon paper during the resistive heating. Additionally, conventional heating element devices require specific discrete electrical connection to the heating element, such as point contact, lone contact, or area contact, that does not change during the resistive heating, wherein the electricalconnection is typically soldered or crimped contact point connected to external wire. Additionally, conventional heating element devices have low surface area per gram. For example, typical surface area of carbon cloth is from 0.1 to 2 m2 / g.

[0045] The term Joule (resistive) heating in this disclosure refers to Joule (resistive) heating of powders that comprise of a collection of individual grains, typically in the size range from 10 nm per grain to 5 mm per grain, wherein each grain is free to move and displace with respect to each other and with respect to the reactor in which they are being contained. The powder grains are in electrical contact with each other and have bulk electrical conductivity or resistivity. One advantage of a powder heater is that ohmic resistance between powder grains allows for lower bulk resistance which in turn helps improve the practical implementation of the Joule heater operation. Other joule heating elements, such as carbon cloth, have very low resistance that makes them operate at much higher currents. It is desirable for the powder to be electrically conductive in the order of 1 to 1000 Ohms (bulk resistance).

[0046] Another advantage of having powder as the heating element instead of conventional heating elements is that powders have greater surface area per gram, typically in the order of 1 to 100 m2 / g. Higher surface areas of the powders are also possible. The electrically conductive powder can also be mixed with secondary powders that have low electrical conductivity or are not electrically conductive at all, wherein the combined powder mixture comprising of electrically conductive and electrically non-conductive powder can be Joule heated to reach temperature ranges from 100°C to 3000°C. Mixture or blend in this invention is defined as a composition of more than one powder material component that are physically combined by means of blending or physical mixing the powder components to randomize their respective grains with respect to each other. For example, a carbon powder component is mixed with plastic powder component to create carbon-plastic powder mixture or carbon-plastic powder blend.

[0047] Joule heating requires that power supply is connected to the electrically conductive powder or powder mixture (blend) to provide voltage potential and electrical current that will resistively (Joule) heat the powder. In one example, the electrical power is applied to the powder through at least two electrodes, typically graphite electrodes, but electrodes made from other high temperature materials such as tungsten or molybdenum are also possible.Composite electrodes made from graphite, brass, copper are also possible. The electrodes may be solid elements, porous elements, paper or wool elements, or their combination thereof. The power for Joule heating may be AC, DC, modified AC or DC, or any combination thereof. In some embodiments the Joule heating power is automatically adjusted with the help of a controller to achieve a desired decomposition temperature which is set as a target. The electrical power can be steady overtime or it can be applied in pulses. In some embodiments, the joule heating power or temperatures can follow a prescribed profile, and in other cases, the controller automatically adjusts to achieve other target set points. The joule heating controller can also adjust the power output applied to the conductive powder inside the reactor based on other sensor inputs. The joule heating controller can also be an adaptive controller, or one that uses artificial intelligence that takes input from multiple sensors and / or process models to compute optimal power output. The controller output may include adjusting Power (Watts), Voltage (Volts), Current (Amperes), duty cycle of an AC power (%), pulse width (ms or sec), pulse pattern, or any combination thereof to control the heating intensity of the conductive powder in the reactor.

[0048] It is desirable to have a thermally resilient reactor suitable for Joule heating operation that can withstand temperatures up to ~3000°C. It is also desirable to have Joule heating capable reactors where the process powder mixture or powder is moved or mixed within the reactor to make a more uniform volume of powder, before, during, and / or after the Joule heating. Additionally, it is desirable to have Joule heating reactorthat can operate in continuous mode or continuous batch mode with high throughput. Additionally, it is desirable to have Joule heating reactors that can be sealed to allow removal of the atmosphere within the reactor, would allow injection of inert or process gases, and will allow exhaust and collection of reactant gases created as the result of the Joule heating process. It is also desirable to have the capability to mix the powder material inside the reactor to produce a more uniform temperature profile during the Joule heating process. One means to achieve this goal, as disclosed here, is to make the electrodes movable with respect to a fixed (stationary) reactor, or alternatively to make the reactor (bucket, tube, box) movable with respect to fixed (stationary) electrodes, or any combination thereof. Movable in this disclosure means the object is capable of rotational motion (rotating), rocking motion (rocking), translation motion (in general X, Y, Z space) in straight orcurved paths. Examples of curved paths are circular and elliptic paths and their 3D versions, spiral and elliptic spiral paths, or any motion combination thereof.

[0049] Figure 2 illustrates an exemplary embodiment of the present invention comprising a thermally resilient rotating / moving graphite bucket 206 that contains electrically conductive powder material mixture / blend 207, a set of fixed (with respect to the bucket reactor) electrodes 202 and 203 that are submerged into the powder material 207 and can mix / move the powder 207 when the graphite bucket 206 is rotating / moving 209, and enable electrical current flow from one electrode 202 to another electrode 203 through the electrically conductive powder 207, wherein the electrical current Joule heats the mixed / moved powder material 207 to change the material's properties. A prototype rotating graphite system is shown in Figure 16A. Alternatively, the graphite bucket 206 and the electrodes 202 and 203 are stationary (fixed) with respect to each other and the Joule heating is conducted on a stationary (fixed) powder material 207. In another embodiment, the Joule heating is conducted on a stationary (fixed) powder material 207 followed by mixing / moving the powder material 207 after pre-prescribed Joule heating time (in milliseconds, seconds, or minutes) or dose (MJ / kg or kWh / kg). Any combination of mixed and / or stationary operation and / or intermittent is possible with the embodiment of Figure 2.

[0050] It is desirable to mix / move the powder to produce a more uniform temperature profile during the Joule heating process. Mixing / moving can occur as the Joule heating process is ongoing, or the mixing / moving can occur during process pauses, or a combination of each approach. Mixing / moving the powder means that grains comprising the powder are moved with respect to each other to randomize their relative position with respect to each other, and their absolute position within the reactor. The graphite bucket motion 209 may be rotational motion, it may be rocking motion, it may be rotational or rocking motion that keeps the electrode-wall gap 221 predominately fixed or a rotational / rocking motion where the electrode-wall gap 221 is intentionally varied, it may be translational motion with fixed electrode-bottom gap 222 predominately fixed, or a translational motion where the electrode-bottom gap 222 is intentionally varied. The electrodes 202 and 203 may be centered with respect to the graphite bucket 206 or they may be off center. The rotational, rocking, or translational motion may be continuous or intermittent. The rotational / rocking motion speed may be for example in therange from 0.1 revolutions per minute (rpm) to about 10 rpm 1. Other rotational speeds are possible. The translational motion speed may be for example from mm / sec to cm / sec.

[0051] In one embodiment of the invention of Figure 2 the electrode pair 202 and 203 have oval shape, as shown in exemplary configuration in Figure 2B, so that the oval electrodes long side aligned with the powder motion / displacement to enable more efficient powder mixing. Alternatively, the shape and size of the electrodes can be different than shown in Figure 2B, and they can be angled with respect to the direction of the powder motion / displacement or they can be asymmetric.

[0052] One advantage of using graphite bucket as a reactor material is its ability to withstand high temperatures in air (>900°C with some oxidation) and even higher temperatures (up to ~3000°C) in inert atmosphere. With presence of powder material 207 inside the graphite reactor 206, the inner walls of the reactor limit the graphite oxidation and allow higher operating temperatures as compared to operating in air.

[0053] The graphite bucket 206 may have many shapes including for example circular, oval, square, rectangular, or polygonal cross section profiles. The graphite bucket 206 may have sidewalls that are not parallel to each other, and / or not perpendicular to the bottom or top of the reactor. For example, the reactor may have conical walls to prevent accumulation of powder 207 to the reactor walls. In one embodiment of this invention the bucket is made from one graphite piece. In anotherembodiment, the bucket is assembled from at least two parts, graphite tube walls and a graphite bottom disk, wherein the multiple graphite parts are held together by mechanical means. In another embodiment, the separate bucket bottom is made from ceramic material that is attached or bolted to the graphite tube walls. In one embodiment of this invention, the graphite reactor walls are cut into at least two parts so as to allow thermal expansion and prevent uncontrolled reactor cracking. The at least two parts of the reactor may be held together with a hose clamp or bolted together.

[0054] Use of ceramic material for the bucket reactor is possible, but it may lead to ceramic material cracking due to the high temperature gradient (temperature difference) from inside the reactor to outside the bucket reactor. In one embodiment of the invention, a ceramic,clay, refractory, concrete, and their combination, bucket reactor, may have their outside walls covered by other thermally insulating material to slow the heat dissipation and minimize the bucket temperature gradient. One class of thermally insulating materials of this invention are powders, such as common sand (quartz powder), SiC powder, refractory powder, clay powder. In one embodiment, a ceramic bucket reactor is inserted into another larger ceramic bucket reactor with the gap filled with sand, as in the prototype system shown in Figure 16B. Another class of thermally insulating materials are cast or bonded materials, such as concrete cast, refractive material cast, clay cast, and other castable materials. In another embodiment of this invention the ceramic reactor is cut in at least two parts so as to allow thermal expansion and prevent uncontrolled reactor cracking. The at least two parts of the reactor may be held together with a hose clamp, or bolted together, or held together with a wall of powder or cast materials on the outside of the reactor assembly.

[0055] The electrically conductive powder material 207 may partially fill the reactor bucket 206 or fully fill the reactor 206. The electrodes 202 and 203 need to be at least partially submerged into the powder material 207 to enable electrical current flow through the powder 207 or to enable mixing / moving the powder 207. For Joule heating reactions of mixed / moved powder or intermittent mixed / moved powder it is preferred that the powder 207 is noncompressed (non-compacted) or partially compressed (compacted) to allow powder mixing / moving. Alternatively, for stationary (fixed) Joule heating operation the powder 207 can be fully compressed (compacted). Alternatively, the powder can be compressed and uncompressed as needed for the process. Without the powder compression, the powder 207 electrical resistance is generally higher than when the powder is compressed. Higher powder resistance is beneficial for better control of the joule heating.

[0056] For a multi electrode embodiment, it is desired to configure the electrode gap spacing 220 and the electrode-wall gap 221 such that the resulting bulk electrical resistance of the powder between the electrodes is higher than the bulk electrical resistance of the powder between the electrode and the wall, forcing the majority of the electrical current to flow from one electrode to the other through the powder volume between the electrodes and not from one electrode to the graphite wall. Therefore, the resulting Joule heating will be highest betweenthe electrodes and lower in the volume of powder near the reactor walls, preventing excessive heating of the reactor walls. In one embodiment of the invention of Figure 2 the electrodebottom gap 222 is such that the resulting bulk electrical resistance of the powder under the electrodes is high forcing the electrical current flow from one electrode to another through the powder volume between the electrodes. Therefore, the resulting Joule heating will be highest between the electrodes and lower in the volume of powder under the electrodes, preventing excessive heating of the reactor bottom. In one example of the embodiment of Figure 2, the inner diameter of the bucket reactor 206 is 12 inches, the electrode gap 220 is 4 inches, the electrode-wall gap 221 is 3 inches, the inner depth of the bucket reactor is 8 inches, and the electrode-bottom gap 222 is 2 inches. Other reactor and electrode dimensions and gaps are also possible with this embodiment.

[0057] In one embodiment of Figure 2, an optional ceramic bottom 213 is present to prevent electrical current flow from the electrodes 202 and 203 to the bottom of the bucket reactor. Electrical flow to the bottom of the bucket would overheat the volume of powder under the electrodes. Presence of ceramic bottom 213 allows the electrodes 202 and 203 to be lowered to almost touching the ceramic bottom, thus more efficiently utilizing the volume of the bucket reactor. In another embodiment the bucket is assembled from at least two parts, graphite tube walls and ceramic bottom disk that is attached or bolted to the graphite tube walls. This configuration does not require additional ceramic bottom 213. A ceramic bucket reactor does not require additional ceramic bottom 213. The electrically insulating bottom 213 may be a quartz disk.

[0058] The system of Figure 2 further may be sealed reactor system so that the Joule heating of the powder is conducted under a vacuum or under an inert atmosphere. Additionally, sealed reactors enable removal of oxygen from the reactor volume, thus allowing higher process temperatures up to ~3000°C without oxidizing and damaging the inside walls of the graphite reactor. Sealed reactor designs also allow exhaust and collection of process gases. In one example of a sealed reactor Joule heating process, the conductive powder mixture 207 includes plastic material that decomposes into hydrogen, syngas, carbon monoxide, carbon dioxide, volatile organic compounds, hydrocarbon gases, fluorine, chlorine, halogen gases, and theircombinations. Exemplary plastic materials include high-density polyethylene (HDPE), polypropylene (PP), polystyrene (PS), polyvinylidene fluoride (PVDF), and glass fiber reinforced plastic (GFRP). In another example of a sealed reactor Joule heating process, the conductive powder mixture 207 may include biomass, coal, or any materials that comprise volatile organic compounds, hydrocarbon oils or gases, wherein the resulting products of the Joule heating process include methane, hydrogen, syngas, carbon monoxide, carbon dioxide, and their combinations.

[0059] Alternatively, a sealed reactor design allows injection of process gases with Joule heating process as described in detail in Mancevski (US 63 / 629,967), and in Mancevski (US 63 / 629,975). Examples of Joule heating processes possible with sealed systems in this disclosure include thermal decomposition of methane, hydrocarbons, organic compound gas, and other gases in general. The disclosed methods and systems also apply to a general method for thermally activated chemical reaction of a gas with a reactant powder that has an affinity for a chemical reaction with the gas at high temperatures, wherein reactant powder is combined (mixed, blended) with an electrically conductive powder, and wherein the gas flows through a joule heated volume of the conductive and reactant powders. In one embodiment, the thermally activated chemical reaction is chlorination of metal oxides and other metal compounds into metal chlorides, wherein the gas is chlorine, and the reactants comprise metal oxides or compounds that are combined (mixed, blended) with the conductive powder. The chlorination process is commonly used in metallurgy for metal extraction from ores.

[0060] A sealed reactor embodiment of Figure 2 may comprise a stationary (grounded) gas tight ceramic lid assembly 211, an O-ring seal 210 between the lid 211 and the bucket reactor 206, that isolates the inside of the reactor from the atmosphere, but allows relative rotation / rocking motion of the bucket 206 with respect to the grounded lid 211, and a set of electrodes 202 and 203 that penetrate the bucket lid 211, making gas tight seal with the lid, and are fixed to the lid. For an embodiment where the graphite bucket 206 is moving / translating with respect to the lid 211 (and the electrodes 202 and 203 fixed to the lid) the lid 211 does not have parts that are inserted into the reactor, and has O-rings that allow lateral (sliding) motionbetween the lid and top reactor walls without losing contact or exposing the reactor to the environment (not shown in Figure 2).

[0061] Optional inlet gas feedthrough 218 may be fixed to the lid 211 to flow process gas inside reactor 206, and an optional outlet feedthrough 214 may also be fixed to the lid 211 to remove process gases. The gas tight lid 211 isolates the reactor 206 from the outside environment but allows inlet and outlet of process gases through inlet 218 and outlet 214 feedthroughs. Gas inlet feedthrough 218 comprises an electrically insulating gas tube (for example, a quartz tube) that is inserted into powder 207 and its end is positioned substantially near the bottom of the reactor 206 or substantially near the insulator bottom 213 without blocking the gas flow. In one example, the tube end is 5 mm from the bottom, but it may be nearer or flush with the bottom. The gas outlet feedthrough 214 comprises a gas tube (electrically conductive or insulating) that is open to the gas tight reactor, and its end is positioned substantially near the top of the reactor 206 without being inserted into the conductive powder 207. In one example, the tube end may be even with the bottom of the lid. The electrically insulating gas tight bucket lid 211 may be a quartz or ceramic structure and may be constructed from several components. In one embodiment the two electrodes 202 and 203 are hollow and may operate as gas inlet 218 and gas outlet 214 in addition to operating as electrodes.

[0062] The electrically conductive powder mixture may comprise at least one or more powder components that are mixed / blended into a mixture, such as, for example electrically conductive carbon materials, carbon materials that are not conductive or do not have high conductivity, electrically non-conductive materials other than carbon, metal-based catalysts, silicon-based materials, and any combination thereof.

[0063] The conductive powder 207 may predominately include electrically conductive carbon materials that include at least one of the group comprised of, but not limited to: calcinated petroleum coke, metallurgical coke, carbon black, amorphous carbon, activated carbon, char, graphene, flash graphene, carbon nanotubes, carbon nanofibers, carbon fiber, or graphitized carbon fiber. The applied joule heating power can be selected to be low so that it will not substantially change the carbon powder crystallinity. On the other hand, the applied joule heating power can be selected to induce substantial changes to the powder crystallinity. Inanother exemplary case, the powder crystallinity may already be already high so that even a high power joule heating will not substantially change the crystallinity. The amorphous carbon or partially graphitized carbon in the conductive powders may, for example, convert into graphite, turbostratic graphite, graphene, turbostratic graphene, polyhedral graphite, polyhedral graphene, turbostratic polyhedral graphite, turbostratic polyhedral graphene, carbon nanotubes and nanofibers, or graphitized fibers. For example, a change in the material's properties of the conductive powder due to Joule heating the mixed / moved powder material includes that, noncrystalline amorphous carbon may be changed to crystalline graphene or graphite, or polycrystalline (partially crystallized) carbon black may be changed to crystalline (fully crystallized) graphene or graphite. A substantial change of crystallinity (graphitization) means changing from one crystallinity state to another (from one graphitization state to another), such as for example from amorphous to fully crystalline (from partially graphitized to fully graphitized). Not a substantial change of crystallinity (graphitization) means that the crystallinity state (graphitization state) remains largely unchanged.

[0064] The conductive powder 207 may also predominately include substantially electrically non-conductive carbon materials such as: anthracite coal, green petroleum coke, asphaltenes, recycled-tire carbon black, bio char, wood char, plant char, pyrolyzed cellulose, conductive polymer, conductive plastic, plastic char, plastic ash, and a combination thereof. Depending on the process temperature, the conductive powders will improve their crystallinity and become more graphitized with each use, resulting in conversion to graphite, turbostratic graphite, graphene, turbostratic graphene, polyhedral graphite, polyhedral graphene, turbostratic polyhedral graphite, turbostratic polyhedral graphene, carbon nanotubes and nanofibers, or graphitized fibers.

[0065] The conductive powder 207 in the embodiments of the present invention can include all possible morphologies including for example: powder, grain, pellets, chunks, spherelike, hollow sphere-like, particles, spheres, nanospheres, microspheres, rods, nanotubes, nanowires, microwires, microfibers, matrix-forming structures, or any combination thereof. The conductive powder 207 includes all material structures, including for example: non-porous, porous, nanoporous, microporous, and having layered structures. The conductive powder 207in the embodiments of the present invention can include all powder sizes, including for example from a few nanometers to a few millimeters. In one embodiment , the conductive powder 207 is Met Coke with grain sizes from 0.5 to 3 mm and surface area of 1-3 m2 / g, in another example the conductive powder 207 is Carbon Black with prime particle size of 30 nm and structure size of about 1 pm, and surface area of 20-40 m2 / g.

[0066] The carbon-based conductive powder 207 may also include non-conductive materials such as polymers and plastics that decompose during the Jule heating process and produce hydrogen gas, carbon formation and morphologies from the carbon atoms in the polymers / plastics (graphite, graphene, nanotubes, nanofibers and any combination thereof), and additional oxygen or nitrogen byproducts. Examples include high density polyethylene, low density polyethylene, polypropylene, polystyrene, Styrofoam, polyethylene terephthalate (PET), polyacrylonitrile (PAN), plastics, waste plastics, cellulose, sugar, paraffins, urea, or any combination thereof. Another possible product of the Joule heating process of the embodiments of this invention is plastics carbonization, wherein the plastic changes its phase and decomposes into carbon, waxes, oils, and gases. Possible gases include hydrogen, carbon monoxide, syngas or methane.

[0067] The carbon-based conductive powder 207 may also comprise metal-based catalysts added to the polymers and plastics that can facilitate the synthesis of 2D and 3D carbon formation and morphologies (graphite, graphene, polyhedral graphene, nano-onions, or any combination thereof), and ID carbon formations with high aspect ratios (nanotubes, nanofibers, nanobelts, or any combination thereof), or improve the yield of the additional carbon formation morphologies. Catalysts include but are not limited to: Fe, Co, Ni, Cu, other transition metals, iron acetate, iron chloride, metal chlorides, chlorides, iron acetylacetonate, iron oxide, cobalt oxide, other transition metal oxide, iron hydroxide, nickel hydroxide, other transition metal hydroxide, or any combination thereof.

[0068] The carbon-based conductive powder 207 may also comprise silicon-based additives such as silicon, silicon dioxide, silicon oxide (SiOx), silicon carbide, or any combination thereof. The silicon-based additives may be in the form of nanospheres, microspheres, nanotubes, nanowires as well as any combination thereof.

[0069] SiC materials are another possible product of the Joule heating process of the embodiments of this invention. When the silicon-based powder comprises silica in the presence of carbon, the silica powder may undergo carbothermal and / or crystallization conversion from amorphous SiO2 to crystallized SiC and crystallized carbon, wherein the SiC and carbon crystallization may be partial, substantial, or full.

[0070] Figure 3 illustrates an exemplary embodiment of the present invention comprising thermally resilient rotating / moving graphite bucket 306 that contains electrically conductive powder material 307, wherein the graphite bucket 306 also functions as an electrode, a single fixed (with respect to the bucket reactor) electrode 302 that is submerged into the powder material 307 and can mix / move the powder 307 when the graphite bucket 306 is rotating / moving in direction 309, wherein an electrical current flows from fixed electrode 302 to bucket electrode 303 through the electrically conductive powder 307, wherein the electrical current Joule heats the mixed / moved powder material 307 to change the material's properties. Alternatively, the graphite bucket 306 and the electrodes 302 are stationary (fixed) with respect to each other and the Joule heating is conducted on a stationary (fixed) powder material 307. In another embodiment, the Joule heating is conducted on a stationary (fixed) powder material 307 followed by mixing / moving the powder material 307 after pre-prescribed Joule heating time (in milliseconds, seconds, or minutes) or dose (MJ / kg or kWh / kg). Any combination of mixed and / or stationary operation and / or intermittent is possible with the embodiment of Figure 3.

[0071] The graphite bucket motion 309 may be rotational motion, it may be rocking motion, it may be rotational or rocking motion that keeps the electrode-wall gap 321 predominately fixed or a rotational / rocking motion where the electrode-wall gap 321 is intentionally varied, it may be translational motion with fixed electrode-bottom gap 322 predominately fixed, or a translational motion where the electrode-bottom gap 322 is intentionally varied. The electrode 302 may be centered with respect to the graphite bucket 306 or it may be off center. The rotational, rocking, or translational motion may be continuous or intermittent.

[0072] In one embodiment of the invention of Figure 3, the electrode 302 has oval shape, as shown in exemplary configuration in Figure 3B, configured to enable more efficient powder mixing. Alternatively, the shape and size of the electrodes can be different.

[0073] The electrically conductive powder material 307 may partially fill the reactor bucket 306 or fully fill the reactor 306. The electrode 302 needs to be at least partially submerged into the powder material 307 to enable electrical current flow through the powder 307 towards the bucket electrode 303 and / or to enable mixing / moving the powder 307.

[0074] In one embodiment of the system disclosed in Figure 3, electrode 302 is configured to be positioned with electrode-bottom gap 322 and the electrode-wall gap 321 such that the resulting bulk electrical resistance of the powder between the electrode 302 and the bucket wall, related to gap 321, is higher than the bulk electrical resistance of the powder between the electrode 302 and the bucket bottom, related to gap 303, forcing the majority of the electrical current to flow between electrode 302 to the graphite wall, through the powder volume in between. Therefore, the resulting Joule heating will be highest between the electrode 302 and the reactor walls, preventing excessive heating of the reactor bottom.

[0075] In one embodiment of Figure 3, an optional ceramic bottom 313 is present to prevent electrical current flow from the electrode 302 to the bottom of the bucket reactor 306. Electrical flow to the bottom of the bucket could overheat the volume of powder under the electrode 302. Presence of ceramic bottom 313 allows the electrode 302 to be lowered to almost touching the ceramic bottom, more efficiently utilizing the volume of the bucket reactor. In another embodiment the bucket is assembled from at least two parts, graphite tube walls and ceramic bottom disk that is attached or bolted to the graphite tube walls. This configuration does not require additional ceramic bottom 313.

[0076] The system of Figure 3 further may be a sealed reactor system so that the Joule heating of the powder is conducted under a vacuum or under inert atmosphere. A sealed reactor embodiment of Figure 3 may comprise stationary (grounded) gas tight ceramic lid assembly 311, an O-ring seal 310 between the lid 311 and the bucket reactor 306, that isolates the inside of the reactorfrom the atmosphere, but allows relative rotation / rocking motion of the bucket 306 withrespect to the grounded lid 311, and an electrode 302 that penetrates the bucket lid 311, making gas tight seal with the lid, and is fixed to the lid. Optional inlet gas feedthrough 318 may be fixed to the lid 311 to flow process gas inside reactor 306, and an optional outlet feedthrough 314 may also be fixed to the lid 311 to remove process gases.

[0077] Embodiments of the invention of Figures 2 and 3 disclose a batch process, where conductive powder mixture 207 or 307 is filled in the bucket reactor 206 or 306 and is Joule heated to change the material's properties. In one example, changing the material's properties may be a change in the material's crystallinity, for example, an amorphous carbon is converted to graphite. In another example, an amorphous carbon is converted to graphene. After the graphitization of the carbon material has been increased with the help of Joule heating process, the graphitized carbon is emptied out from the reactor and new un-graphitized carbon is filled into the reactor.

[0078] Embodiments of the invention of Figures 2 and 3 can be converted to a continuous process by adding an exit port at the bottom of the bucket reactor (not shown in the figures) that allows continuous removal of graphitized carbon and synchronized insertion of un-graphitized carbon from the top of the bucket reactor.

[0079] The embodiment of Figure 4 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 2, wherein the bucket reactor is replaced by a ceramic tube reactor 406 that is slanted downwards, more specifically it is positioned nearly horizontally wherein the entry side of the reactor 406 is elevated with respect to the exit side of the reactor 406 and the powder 407 (unreacted / unprocessed) and 408 (reacted / processed) is moved / propelled through the tube reactor 406 by the help of rotational / rocking motion 409 and gravity towards the exit side of the reactor 406 in a continuous manner. Optionally, a flow of inert gas 418 can be forced into the tube reactor to provide inert atmosphere inside the reactor and to remove unwanted oxygen.

[0080] A set of fixed / stationary (with respect to the tube reactor) electrode plates 402 and 403 is disclosed, that may be submerged into the unreacted powder material 407 and can mix / move the powder 407 when the tube reactor 406 is rotating / moving in direction 409, andwherein the electrode plates 402 and 403 enable electrical current flow from one electrode 402 to another electrode 403 through the electrically conductive powder 407, wherein the electrical current Joule heats the mixed / moved unreacted powder material 407 to change the material's properties into a reacted powder 408 that moves (is propelled) through the tube reactor 406 by the help of rotational / rocking motion 409 and gravity towards the exit side of the reactor 406 in a continuous manner. In one example, the unreacted powder material 407 is amorphous carbon and the reacted powder 408 is graphite or graphene.

[0081] Alternatively, the tube reactor 406 and the electrodes 402 and 403 are stationary (fixed) with respect to each other and the Joule heating is conducted on a stationary (fixed) powder material 407 followed by mixing / moving the powder material 407 after it has been processed (its properties changed). The process can be defined by pre-prescribed Joule heating time (in milliseconds, seconds, or minutes) or dose (MJ / kg or kWh / kg).

[0082] Mixing / moving of the powder 407 can occur as the Joule heating process is ongoing, or the mixing / moving can occur during process pauses, or a combination of each approach. The electrodes 402 and 403 may be centered with respect to the tube reactor 406 or they may be off center. The rotational or rocking, or translational motion may be continuous or intermittent.

[0083] In one embodiment of the invention of Figure 4, the electrode pair 402 and 403 have rectangular shape, as shown in exemplary configuration in Figure 4B, wherein the powder 407 and 408 is in physical contact to the electrodes. Alternatively, the shape and size of the electrodes can be different than shown in Figure 4B, while still accomplishing the same function to achieve the same result.

[0084] The tube reactor 406 may be made from electrically insulated material or from graphite. The reactor may be constructed from ceramic such as quartz, nitride bonded silicon carbide - NB SiC, silicon carbide - SiC, aluminum nitride - AIN, high temperature steels (Hastelloy alloy, Inconel alloy, Nickel based allows), cement, concrete, SiC based refractories and aluminum- based refractories and their combination bit not limited to these.

[0085] The size of the tube reactor (diameter and length) from Figure 4 may depend on the desired throughput and power availability. In one example, the tube reactor is a ceramic tube with 6 in. diameter and 3 ft length, having a reactor volume of 22 L. The reactor shape may be other than a full tube, such as for example half tube.

[0086] The electrically conductive powder material 407 of the Figure 4 embodiment may partially fill the tube reactor 406. The electrodes 402 and 403 need to be at least partially submerged into the powder material 407 to enable electrical current flow through the powder 407 and to enable mixing / moving the powder 407 when the tube reactor 406 is rotating / rocking 409. For Joule heating reactions of mixed / moved powder it is preferred that the powder 407 is non-compressed (non-compacted).

[0087] A tube reactor may get damaged by excessive heat to the bottom arc of the tube reactor where the powder material 407 and 408 lies. In one embodiment of the invention, the outside of a ceramic tube reactor is covered by another thermally insulating material to slow the heat dissipation and minimize the tube temperature gradient. In one example, thermally insulating material is cast or bonded over the outside of the tube reactor. Materials, such as concrete cast, refractive material cast, clay cast, and other castable materials may be used.

[0088] Alternatively, the tube reactor 406 and electrodes 402 can be configured to minimize excessive heating at the bottom arc of the tube reactor where the powder material 407 and 408 lies. In one embodiment of the invention of Figure 4, the most intense Joule heating and the highest process temperatures are between the electrodes and lower process temperature in the volume of powder 407 at the bottom arc of the tube reactor. This can be achieved by controlling the gap between the electrodes 402 and 403 and the bottom of the tube reactor 406 such that the volume of powder 407 between them acts as a thermal insulator. As the powder 407 moves (is propelled) through the tube reactor 406 in a continuous manner, the mixing of the powder 407 ensures that substantially all of the powder will pass through the hot zone between the electrodes, while some of the powder residence time will be at the bottom of the tube.

[0089] The embodiment of Figure 5 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 3, wherein the graphite bucketreactor is replaced by a graphite tube reactor 503 that is slanted downwards, more specifically it is positioned nearly horizontally wherein the entry side of the reactor 503 is elevated with respect to the exit side of the reactor 503 and the powder 507 (unreacted / unprocessed) and 508 (reacted / processed) is moved / propelled through the tube reactor 503 by the help of rotational / rocking motion 509 and gravity towards the exit side of the reactor 503 in a continuous manner. Optionally, a flow of inert gas 518 can be forced into the tube reactor to provide inert atmosphere inside the reactor and to remove unwanted oxygen.

[0090] Single fixed / stationary (with respect to the tube reactor) electrode 502 may be submerged into the unreacted powder material 507 and can mix / move the powder 507 when the tube reactor 503 is rotating / moving in direction 509, and wherein the electrode 502 enables electrical current flow from fixed electrode 502 to rotating / rocking tube electrode 503 through the electrically conductive powder 507, wherein the electrical current Joule heats the mixed / moved unreacted powder material 507 to change the material's properties into a reacted powder 508 that moves (is propelled) through the tube reactor 503 by the help of rotational / rocking motion 509 and gravity towards the exit side of the reactor 503 in a continuous manner. In one example, the unreacted powder material 507 is amorphous carbon and the reacted powder 508 is graphite or graphene. Alternatively, the tube reactor 503 and the electrode 502 are stationary (fixed) with respect to each other and the Joule heating is conducted on a stationary (fixed) powder material 507 followed by mixing / moving the powder material 507 after it has been processed (its properties changed). The process can be defined by preprescribed Joule heating time (in milliseconds, seconds, or minutes) or dose (MJ / kg or kWh / kg). Mixing / moving of the powder 507 can occur as the Joule heating process is ongoing, or the mixing / moving can occur during process pauses, or a combination of each approach. The electrode 502 may be centered with respect to the tube reactor 503 or may be off center. The rotational or rocking, or translational motion may be continuous or intermittent.

[0091] In one embodiment of the invention of Figure 5, the electrically conductive powder material 507 partially fills the tube reactor 503. The electrode 502 needs to be at least partially submerged into the powder material 507 to enable electrical current flow through the powder 507 and to enable mixing / moving the powder 507 when the tube reactor 503 isrotating / rocking 509. For Joule heating reactions of mixed / moved powder it is preferred that the powder 507 is non-compressed (non-compacted). As the powder 507 moves (is propelled) through the tube reactor 503 in a continuous manner, the mixing of the powder 507 ensures that substantially all of the powder will pass through the hot zone, thus ensuring optimal material conversion.

[0092] The shape and position of the electrode can be used to control the location of the hottest zone within the tube reactor. In one embodiment of the invention of Figure 5B, the electrode 502 has an oval shape. With centered oval electrodes, the shortest gap 520 with respect to the tube is between the oval electrode and the bottom arc of the tube reactor where the bulk powder resistance will be the lowest and therefore have the most intense Joule heating and the highest process temperatures.

[0093] Alternatively, if the oval electrode is off center with respect to the tube center axis (not shown in Figure 5B), then the shortest gap with respect to the tube will be to the tube wall and in the direction of the offset, where the bulk powder resistance will be the lowest and therefore have the most intense Joule heating and the highest process temperatures.

[0094] In one embodiment of the invention of Figure 5C, the electrode 502 has flared shape. The shortest electrode gap 521 will be between the edges of the flared electrode 502 and the tube wall, away from the bottom arc of the tube. The bulk powder resistance in the gap 521 will be the lowest, and may therefore have the most intense Joule heating and the highest process temperatures.

[0095] The embodiment of the Figure 6 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 5, wherein the graphite tube reactor 606 is a sealed reactor and is capable of operating in a continuous process mode. The system of Figure 6 comprises additional components to improve the Joule heating process in a sealed environment. The tube reactor is sealed by stationary ceramic end cap 611 positioned on the elevated side of the tube reactor 606, and a stationary ceramic end cap 613 positioned on the lowered side of the tube reactor 606. Stationary ceramic end caps 611 and 613 are grounded and do not move or rotate. Stationary ceramic end caps 611 and 613 comprisesliding gas seals 610 that enable the graphite tube 606 to rotate or rock in direction 609 with respect to the stationary end caps 611 and 613 without changing the atmosphere (vacuum or inert gas) inside the tube 606. Electrode connector 601A is electrically connected to the electrode 602 through a sealed passthrough (not shown in the figure) on the stationary end cap 611. Electrode connector 601B is electrically connected to the graphite tube reactor 606 that is also an electrode.

[0096] The embodiment of Figure 6 may comprise one stationary electrode 602 with cylindrical shape that is centered with respect to the tube reactor 606 center axis. The electrode 602 may be stationary with respect to a rotating / rocking graphite tube reactor 606, and may be fixed in place with ceramic electrode spacers 612 that connect the electrode 602 to a stationary ceramic end cap 611. The embodiment of Figure 6 may also comprise solids and gas feeder assembly 625 that may comprise of an optional powder feeder 607 and optional gas inlet feedthrough 618. The embodiment may also comprise of an optional powder dispenser 615 and an optional gas outlet feedthrough 614. Powder material feeders are well known in the art of powder transport and typically use corkscrew mechanisms to feed the powder inside vacuum or inert atmosphere chambers. The processed materials dispenser 615 is configured to allow removal of the processed powder from the sealed reactor to a collection bin outside of the reactor while keeping the sealed environment. In one example, the unreacted powder material is amorphous carbon and the reacted / processed powder is graphite or graphene.

[0097] The embodiment of Figure 6 also comprises an optional cold finger with heat exchange 623 that is connected to the stationary ceramic end caps 613 without breaking the sealed environment. The cold finger enables process gasses within the sealed reactor 606 to be condensed into condensed materials 616 and captured and collected. Cold fingers or cold traps are devices and systems well known in the industry, specifically the operation of processes in vacuum chambers. The purpose of cold fingers / traps is to provide a cold surface where vapors may condensate into liquids or solids that can be collected.

[0098] Figure 7 illustrates an exemplary embodiment of the present invention comprising thermally resilient graphite box reactor 703 that may comprise of a graphite bottom 705, graphite side walls 706 covering the long side of the box, ceramic end walls 712 on each side ofthe graphite box, and an open top that allows insertion and removal of feedstock materials such as powder material. The top side of the box reactor 703 may be optionally partially closed, fully closed, or opened and closed as needed for a process. The graphite bottom 705 and the graphite walls 706 collectively function as one of the electrodes of the reactor system for a Joule heating process. In one embodiment, the graphite bottom 705 and the graphite walls 706 may be made from one graphite piece, and in another embodiment, separate parts may be bolted together. In another embodiment, the graphite walls 706 can be made from ceramic material, making the bottom graphite 705 the only counter electrode.

[0099] The graphite box reactor 703 may also comprise a rod graphite electrode 702 that spans the ceramic end walls 712 and may penetrate at least one of the ceramic end walls 712 so that electrical contact may be made with it from the outside of the reactor. Alternatively, the graphite electrode 702 may have the same length as the box length and be restrained to the ceramic end walls 712 by metal rods or bolts that penetrate the ceramic end walls 712, also allowing an electrical connection to the electrode 702. Rod electrode 702 is preferably positioned such that it does not contact any of the graphite walls 706 or graphite bottom 705 counter electrodes.

[0100] The graphite box reactor 703 contains electrically conductive powder material 707 (unreacted / unprocessed) and 708 (reacted / processed), that may partially fill or fully fill the graphite box reactor 703. The position of the rod electrode 702 is such that it is submerged into the powder material 707 and 708 and is in physical contact to the powder material.

[0101] During a Joule heating process, power is applied to electrode 702 and counter electrodes 705, 706 wherein an electrical current flows from the rod electrode 702, through the volume of electrically conductive powder 707 or 708, to the counter electrodes 705, 706, and vice versa, wherein the electrical current Joule heats the powder material 707 to convert it into processed material 708. The power supply for the Joule heating may be AC or DC power supply. In one example, the unreacted powder material 707 is amorphous carbon and the reacted powder 708 is graphite or graphene. In another example, the unreacted powder material 707 comprises a mixture of silica and carbon powder and the reacted powder 708 comprises silicon carbide.

[0102] In one embodiment of Figure 7, the electrode 702 may have a cylindrical shape and is stationary with respect to the box reactor counter electrodes 705, 706. In another embodiment, the electrode 702 has an oval shape (where the oval shape is inside the reactor volume and rod shape that allows rotation outside the reactor), and is capable of mixing / moving the powder 707, 708 during and / or after a Joule heating process. The mixing / moving the powder 707 may be continuous or intermittent.

[0103] The shape and position of the electrode can be used to control the location of the hottest process zone within the box reactor. In one embodiment of the invention of Figure 7 the electrode 702 is a graphite rod centered with respect to the graphite sidewalls 706, wherein the gap to the sidewalls 706 is larger than the gap with respect to the graphite bottom 705. Therefore, the electrical resistance of the volume of bulk powder 708 near the shortest gap will be the lowest and therefore have the most intense Joule heating and the highest process temperatures (hot zone 725), as illustrated in Figure 7.

[0104] Alternatively, if the electrode 702 shape is oval and rotating / moving (not shown in the figure), the smallest gap between the electrode 702 and the counter-electrode assembly 705, 706 may change as the oval electrode 702 rotates / rocks, related to the position of the oval electrode apex with respect to the nearest graphite counter electrode (wall or bottom), thus creating a hot zone 725 that moves between the bottom of the box to the sides of the box, which may result in Joule heating the powder 707, 708 more uniformly. In addition to the rotating / rocking hot zone 725, the rotation / rocking of an oval electrode 702 may also be capable of mixing / moving the powder 707, 708 to achieve more uniform conversion of the unprocessed (feedstock) powder 707 to a processed powder 708.

[0105] In one method of Joule heating a powder, a fresh batch of unprocessed powder 707 is fed from the open top to the graphite box reactor 703 until it is filled to a desired volume that at least partially covers the electrode 702 so as to enable electrical contact with the powder 707. Optionally, a flow of inert gas 718 can be forced into the tube reactor to blanket the top surface of the powder 707 and thus provide an inert atmosphere inside the reactor. Alternatively, if the reactor box 703 has a cover, the gas inlet 708 may be conducted via a inlet port.

[0106] After the powder 707 has been converted to processed powder 708 by the Joule heating process, the batch of processed powder 708 may be removed. In one method, the reactor may be flipped over and the processed powder 708 may be dumped into a collection bin. Alternatively, the bottom electrode 705 may be removable and the processed powder 708 may be dumped into a collection bin. Alternatively, a slit or opening (not shown in the figure) may be utilized to remove processed powder 708 in a continuous manner while a new powder 707 is added from the top also in a continuous manner.

[0107] The embodiment of Figure 8 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 7, wherein the graphite box reactor is replaced by graphite box reactor 803 comprising of a graphite side walls 806, graphite bottom wall 805, and wherein the box reactor 803 may be suitable for a sealed reactor operation, for a continuous operation reactor, or for a sealed continuous operation reactor.

[0108] Figure 8 illustrates an exemplary embodiment of the present invention comprising graphite side walls 806 constructing the top sides of the reactor, graphite half-tube bottom 805, ceramic end walls 812 on each side of the graphite box, and an open top that allows insertion and removal of feedstock materials such as powder material, to propel the material downwards. The top side of the box reactor 803 may optionally comprise a ceramic plug 811 for sealed operation of the reactor 803.

[0109] The graphite half-tube bottom 805 and the graphite side walls 806 collectively function as one of the electrodes of reactor system for a Joule heating process. In one embodiment, the graphite bottom 805 and the graphite side walls 806 may be made from one graphite piece, and in another embodiment, the separate parts may be bolted together. In another embodiment, the graphite walls 806 can be made from ceramic material, making the bottom graphite 805 the only counter electrode.

[0110] The graphite box reactor 803 may also comprise a rod graphite electrode 802 that may span the ceramic end walls 812 and penetrate the ceramic end walls 812 so that electrical contact may be made with it from the outside of the reactor. Rod electrode 802 is preferablypositioned such that it does not contact any of the graphite walls 806 or graphite bottom 805 counter electrodes.

[0111] The graphite box reactor 803 may contain powder material that comprises of a starting feedstock material 807, partially processed / converted material 809, and fully processed / converted material 808, where the feedstock conversion degree depends on the maximum temperature exposure of the feedstock in the reactor. The starting feedstock material 807 is converted to partially converted material 809 as it is exposed to lower reactor process temperatures that exist at the top of the reactor 803. For example, the material temperature at the top of the reactor may be 300 C to 900 C where the heat is due to the conduction heat from the powders in the hotter zones of the reactor, near the reactor bottom, where the Joule heating primarily occurs. The partially converted material 809 may be converted to fully converted material 808 resulting from a Joule heating process conversion and exposure to high temperatures. For example, the material temperature near the bottom of the reactor may be in the range from 1000°C to 3000°C due to the Joule heating process.

[0112] It may be desired that reactor 803 is always full of powder material and the material flows / moves / propels from the reactor top to the reactor bottom, downwards, as indicated by material flow direction 820. When powder material passes near the electrode 802, it is exposed to a Joule heating process, and then exits reactor 803 as fully converted material 808, as indicated by gas / solids out path 814. The powder material flow may be created by a gravity feed, by pushing / moving the material from the reactor top to the reactor bottom, and / or by removing material from the bottom of the reactor. Other means of powder agitation and movement may be utilized.

[0113] Rod electrode 802 may be submerged into the powder material 808 and may be in physical contact to the powder material. During a Joule heating process, power is applied to electrode 802 and counter electrodes 805, 806, wherein electrical current flows from the rod electrode 802, through the volume of electrically conductive powder 808, to the counter electrodes 805, 806, and vice versa, wherein the electrical current Joule heats the partially converted material 809 to convert it into fully converted material 808. In one example, the feedstock powder material 807 is amorphous carbon, the partially converted material 809 ispartially graphitized carbon, and the fully converted material 808 is graphite or graphene. In another example, the feedstock powder material 807 may comprise a mixture of silica and amorphous carbon powder, the partially converted material 809 may comprise mixture of silica and partially graphitized carbon, and the fully converted material 808 may comprise silicon carbide and / or graphene or graphite.

[0114] In one embodiment of Figure 8, the electrode 802 may have a cylindrical shape and may be stationary with respect to the box reactor counter electrodes 805, 806, and the powder material may be Joule heated as it is moved in the rector volume between the electrode 802 and the counter electrodes 805, 806. In one embodiment of the invention of Figure 8, the electrode 802 may be a graphite rod centered with respect to the graphite sidewalls 806 and the graphite bottom 805. Therefore, the electrical resistance of the bulk powder 808 per unit volume in the space between the electrode 802 and counter electrode 805, 806 will be similar and therefore the Joule heating (that depends on the electrical resistance) in this space will also have similar intensities and powder temperatures, creating approximately uniform hot zone 825 that may be approximately symmetrical around the cylindrical electrode 802.

[0115] In another embodiment of the invention of Figure 8, the process hot zone may be biased to be created in the space between the electrode 802 and the bottom arc of the graphite half-tube bottom 805, where the bulk powder resistance will be the lowest and therefore have the most intense Joule heating and the highest process temperatures. In this embodiment, the rod electrode 802 may be centered with respect to the graphite sidewalls 806 but positioned closer to the graphite bottom 805, wherein the gap to the sidewalls 806 may be larger than the gap with respect to the graphite bottom 805. Therefore, the electrical resistance of the volume of bulk powder 808 near the smaller gap will be the lowest and therefore have the most intense Joule heating and the highest process temperatures (hot zone 825), as illustrated in Figure 8. Therefore, the Joule heating (that depends on the electrical resistance) and the resulting temperature (hot zone 825) may not be symmetrical around the cylindrical electrode 802 but may instead have the hot zone closer to the bottom of the reactor than the sides of the reactor near the electrode 802.

[0116] In one method of Joule heating a powder, a fresh batch of feedstock powder 807 may be continuously fed into the reactor with a powder feeder integrated with the ceramic plug lid 811, wherein the reactor 803 is filled with powder material and feedstock powder 807 replenishes powder that has moved done the reactor 803. After the feedstock powder 807 has been fully converted by a continuous Joule heating process to a fully converted material 808, the powder 808 is continuously removed from the bottom of the reactor 803 into a collection bin, as shown in Figure 8. Optional ceramic guides 813 may be utilized to direct the direction of the powder flow 808 from the reactor exit. The operation of the system as shown in Figure 8 may be continuous (continuous powder flow), continuous batch (one batch at time but in a continuous manner), or intermittent (have pauses in the process to remove processed powder and insert new powder), or any combination thereof.

[0117] The embodiment of Figure 9 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 8, wherein the rod electrode of the reactor may be replaced by an oval electrode 902, and wherein the oval electrode 902 may be capable of operating in rotating / rocking motion 909, to enable mixing / moving of the powder material 909, 908, inside the reactor and enable flow / transport of the powder material in direction 920 from the top of the reactor to the bottom exit 914 of the reactor.

[0118] The electrode 902 of this embodiment is an oval shape, wherein the oval shape may be inside the reactor volume and may have one or more cylindrically shaped extensions that protrude outside of the reactor to allow the electrode 902 to undergo rotational / rocking motion 909 that aids the mixing / moving of the powder 908, and wherein the extensions enable electrical connection to a power supply. The mixing / moving the powder may be continuous or intermittent.

[0119] When the electrode 902 shape is oval and rotating / rocking in direction 909, the smallest gap between the oval electrode 902 and the counter-electrode assembly 905, 906 may change as the oval electrode 902 rotates / rocks, related to the position of the oval electrode apex with respect to the nearest graphite counter electrode (wall or bottom), creating a hot zone 925 that moves between the bottom of the box to the sides of the box, Joule heating the powder 909, 908 more uniformly. In addition to the rotating / rocking hot zone 925 the rotation / rockingof an oval electrode 902 is also capable of mixing / moving the powder 909, 908 to achieve more uniform conversion of the unprocessed (feedstock) powder 907 to a processed powder 908.

[0120] The embodiment of Figure 10 illustrates an exemplary embodiment of the present invention that is analogous to the embodiment disclosed in Figure 9, wherein the oval electrode of the reactor may be replaced by mixing electrode 1002, wherein the mixing electrode 1002 may be capable of operating in rotating / rocking motion 1009, to enable efficient mixing / moving of the powder material 1009, 1008, inside the reactor and enable efficient flow / transport of the powder material in direction 1020 from the top of the reactor to the bottom exit 1014 of the reactor.

[0121] The electrode 1002 of this embodiment may have a cylindrical shape and comprising of multiple fin / protrusion extensions 1016 uniformly spread over the length of the electrode that is inside the box reactor 1003. In one embodiment, the fin / protrusion extensions 1016 are rectangular plates attached perpendicularly to the cylinder core. One advantage of the fin extensions 1016 is for the fins to reach deeper into the volume of the powder material 1008 and mix it more uniformly compared to a uniform oval electrode. Another advantage of the fin extensions 1016 is that they can aid the transport of the powder material in direction 1020 from the top of the reactor to the bottom exit 1014 of the reactor compared to a uniform oval electrode. Another advantage of the fin extensions 1016 is that they can create multiple uniform hot zones that rotate in proportion to the rotation of the electrode. The principle of creating rotating zones was described in detail in the disclosure of Figure 9. When rotating electrode 1002 has fin extensions 1016, the smallest gap between the electrode 1002 and the counter-electrode assembly 1005, 1006 is determined by the apex of the fin extensions 1016 with respect to the counter-electrode assembly 1005, 1006. Presence of multiple evenly spaced fins 1016 created multiple gaps where the bulk powder electrical resistance is lower than the average bulk powder electrical resistance, creating multiple rotating hot zones, enabling Joule heating that is more uniform.

[0122] The next section describes methods and processes possible with the reactors and systems disclosed in this disclosure.

[0123] The prior art process flow diagram of converting carbon source into graphene by Tour et al., shown in the flow diagram of Figure 11, requires that the carbon source that is not graphene is compressed within a quartz tube reactor, and that voltage pulses are applied to a static (not mixed) material, resulting in some of the carbon material being converted into graphene. One major limitation of this method is that due to the powder non-uniformity, the electrical current path may also be non-uniform, resulting in non-uniform conversion of carbon into graphene and leaving the possibility that in some cases not all carbon is converted into graphene. The prior art Joule heating process of Figure 11 could be repeated until a desired minimum portion of carbon material is converted to graphene. However, unless the material from the first batch is mixed and repacked, which is not disclosed in this prior art, the electrical current will tend to flow through the same fraction of the material that was already Joule heated, thus leaving unconverted carbon in the batch.

[0124] Figure 11 summarizes the prior art for graphene synthesis via Joule heating. This process comprises of the following steps. Step 1: Compress a conductive carbon source material that is not graphene. Step 2: Apply voltage pulses to the carbon material wherein resulting joule heating converts some carbon material into graphene.

[0125] In the prior art disclosure of Figure 11, the purpose of the Joule heating is to convert a carbon source that is not graphene and convert it into graphene. Unlike the prior art, here, one of the embodiments uses a primary carbon powder source, comprising of powder grains and having a bulk powder electrical resistance, without the intent to convert it into graphene or graphite, but instead to use it as an electrically conductive media that can be Joule heated because of its bulk resistance, and use the heat from the primary powder to heat second powder that is not electrically conductive or has poor electrical conductivity, wherein a second powder is mixed with the primary powder, to change the material properties or phases of the second powder. The second powder may comprise carbon atoms and after conversion it may comprise amorphous carbon, graphitized carbon, or crystalline carbon (like graphene, graphite, carbon nanotubes).

[0126] One method of achieving this goal is to use a primary carbon source powder that is already graphene, graphite, carbon nanotubes, or their combination, such that Joule heatingthis primary powder would not substantially change its crystallinity, and it would remain as graphene, graphite, carbon nanotubes, or their combination, at the process temperature, while the secondary powder would change its properties.

[0127] Another method of achieving this goal is to use a primary carbon source powder and Joule heat this primary powder at low power or low temperatures that are not sufficient to change the material properties of the primary powder, but where the low temperatures are sufficient to change the material properties of the second powder.

[0128] Figure 12 summarizes the processes for indirect joule heating of mixed powders. In one embodiment of this invention, the process comprises of the following steps. Step 1: Mix carbon powder with a second powder wherein the powder mixture is electrically conductive. Step 2: Apply low temperature joule heating (low power) to the powder mixture (while optionally moving the powder) resulting in changing the material properties or phases of the second powder, and wherein the carbon powder is not converted to graphene or graphite (carbon powder crystallinity is not substantially changed). Step 3: Collect at least partially the changed materials or phases (gases, condensed materials, and solids) of the second powder.

[0129] Figure 13 summarizes the processes for indirect continuous Joule heating of mixed powders. In one embodiment of this invention, the process comprises of the following steps. Step 1: Fill a reactor with a mixture of carbon powder and a at least one second powder, wherein the carbon powder is in physical contact with the second powder, and wherein the carbon powder is electrically conductive, and the combined mixture is electrically conductive. Step 2: Apply electrical power to the mixture (while optionally moving the mixture) resulting in joule heating of the carbon powder (wherein carbon powder crystallinity is not substantially changed), and wherein heat is transferring from the carbon powder to the second powder, resulting in at least partially modifying the properties of the second powder and / or at least partially changing the material phase of the second powder. Step 3: Collect at least partially the resulting second powder, which has modified properties and / or changed material phase. Step 4: Mix in additional second powder.

[0130] Examples of primary carbon powder of this process include graphene, graphene flakes, graphene nanoplatelets, turbostratic graphene, polyhedral graphene, ordered graphene, graphite, turbostratic graphite, ordered graphite, carbon nanotubes, carbon fiber, graphitized carbon fiber, calcinated petroleum coke, metallurgical coke, carbon black, biochar, plastic char, amorphous carbon, and their combination thereof.

[0131] Examples of secondary powder of this process include new and waste plastic materials such as PP, PE, HDPE, LDPE, PET, PS, PVC, PC, ABS and mixed waste but not limited to these examples. The secondary plastic powder may also include polymers. The secondary material does not need to be in powder form, it can include waxes, oils, and gases. The secondary material may include petroleum pitch, tar, liquid hydrocarbons, petroleum oil, crude oil, paraffines, asphaltenes, sugar, urea, alcohols, and their combination thereof. The secondary material may also include gases like methane, (CH4), acetylene (C2H2), ethylene (C2H4), ethane (C2H6), and propane (C3H8), but are not limited to these.

[0132] In one embodiment of this innovation, the secondary powder may comprise plastic materials, wherein low power Joule heating produces process temperatures may be in the range from 100°C to 1000°C, wherein the plastic material's properties include change in its solid phase by thermal decomposition into other phases, for example, the plastic may change into wax, oil, methane, hydrogen, carbon char, or any combination thereof. In another embodiment of this innovation, the secondary powder comprises crude oil, wherein low power Joule heating produces process temperatures in the range from approximately 150°C to 450°C, wherein the crude oil changes into asphalt, petroleum coke, naphtha, oils, petroleum gases, or any combination thereof. The gases can be further condensed to produce petroleum-based liquids like kerosene, diesel, gasolene, or any combination thereof.

[0133] The embodiments of this innovation include methods and systems for thermal decomposition of solids, liquids, and gases. The disclosed methods and systems also apply to a general method for the thermally activated chemical reaction of a gas with a reactant powder that has an affinity for a chemical reaction with the gas at high temperatures, wherein a reactant powder is combined (mixed or blended) with an electrically conductive powder.

[0134] One prior art disclosed by Xu S. et al. (Separation of Lithium from Ores in Seconds. ChemRxiv. 20 August 2024, Version 1) describes a method for lithium recovery from lithium- comprising ores using Joule heating of carbon paper. This prior art discloses a conversion of earth-abundant Li (lithium) ore, alpha-spodumene, wherein the Li ore is loaded on top of a carbon paper that is Joule heated to about 1000°C to 1200°C, which in turn heats the Li ore via conductive heat transfer to thermally convert it into beta-spodumene in seconds, wherein commercially usable LiCI (lithium chloride) is extracted from the beta-spodumene with 1 M HCI (1 Molar hydrochloric acid). This prior art does not disclose Joule heating of an electrically conductive powder mixture that comprises carbon powder and Li ore powder as it is disclosed here. Joule heating of carbon paper (or cloth) that in turn heats another material is substantially different and significantly less efficient than direct Joule heating by passing an electrical current though an electrically conductive powder mixture that incorporates materials that need to be processed, as disclosed herein.

[0135] This prior art also discloses a conversion of alpha-spodumene (Li compound), wherein the alpha-spodumene is loaded on top of a carbon paper, under an atmosphere of Ch (chlorine gas), wherein the carbon paper is Joule heated to about 1400°C to 1600°C, which in turn heats the alpha-spodumene via conductive heat transfer to thermally convert it into LiCI in seconds without any acid treatment. Again, this prior art does not disclose direct Joule heating of an electrically conductive powder mixture that comprises carbon powder and Li comprising powder as disclosed herein.

[0136] Figure 14A summarizes the prior art of Xu S. et al. for Joule Heating processes for Lithium recovery. This process comprises of the following steps. Step 1: Place alpha-phase spodumene lithium ore powder onto a carbon paper heater located inside a quartz tube reactor. Step 2: Apply joule heating to the carbon paper wherein heat is transferring from the carbon paper to the lithium powder resulting in changing the lithium powder from alpha-phase to betaphase. Step 3: Leach LiCI from the beta-phase lithium powder with diluted acid.

[0137] Figure 14B summarizes the prior art of Xu S. et al. for Joule Heating processes for Lithium separation. This process comprises of the following steps. Step 1: (a) Place alpha-phase spodumene lithium ore powder onto a carbon paper heater located inside a sealed quartz tubereactor and (b) fill chlorine gas inside the quartz tube reactor. Step 2: (a) Apply joule heating to the carbon paper wherein heat is transferring from the carbon paper to the lithium powder resulting in changing the lithium powder from alpha-phase to beta-phase, (b) wherein the betaphase powder reacts with chlorine gas to form volatile LiCI that condenses on the inner surfaces of the quartz tube. Step 3: Collect the condensed LiCI by rinsing quartz tube with DI water.

[0138] One exemplary disadvantage of the prior art disclosure for Lithium recovery and separation is the inefficient indirect conduction heating of the Li comprising material using a separate heating element, i.e., Joule heated carbon paper. Additionally, because of the two- dimensional nature of the carbon paper, more Li comprising material is loaded to the paper. The less efficiency of the indirect conduction heat transfer is due to higher thermal transfer losses. Therefore, the prior art methods for Lithium recovery and separation are not scalable.

[0139] To overcome the limitations of the prior art methods for Lithium recovery and separation, this invention discloses a method where the Li comprising material, in powder form, is mixed with at least one electrically conductive carbon powder to make an electrically conductive powder mixture that can be Joule heated as three-dimensional volume of powder with the exemplary reactors of Figures 2 to 10 described in this disclosure. The Joule heating method of Figures 2 to 10 is scalable, where masses and volumes in range from a few grams to 100s of kilograms can be processed in one of the disclosed reactors.

[0140] Figure 15A summarizes the Joule heating processes for Lithium extraction without the use of chlorine gas. In one embodiment of this invention, the process comprises of the following steps. Step 1: Fill a reactor volume with a mixture of carbon powder, lithium containing powder, and chlorinating agent powder, wherein the powder mixture is electrically conductive. Use of chlorinating agent powder eliminates the use of chlorine gas in the Joule heating reactor. Examples of chlorinating agent powders include common plastics such as polyvinyl chloride (PVC), chlorinated polyethylene (CPE), chlorinated polypropylene (CPP), and chlorinated polyvinyl chloride (CPVC). The plastics may be new or from waste. Step 2: Apply joule heating to the powder mixture (optionally moving the powder) resulting in producing gases, condensed matter, and / or solid lithium secondary products. During this step, depending on the process temperatures, the carbon may be graphitized or converted to graphite or graphene. Optionally,the carbon powder is not converted to graphene or graphite, or the carbon powder crystallinity is not substantially changed. Step 3: Collect at least partially the resulting lithium secondary products (gases, condensed matter, and / or solids) from the mixture. Step 4: Optionally, additional lithium and / or chlorination powder may be added and mixed to the reactorto increase the efficiency of the conversion process and / or to operate the process in a continuous mode.

[0141] Figure 15B summarizes the Joule heating processes for Lithium extraction with the use of chlorine gas. In one embodiment of this invention the process comprises of the following steps. Step 1: Fill a sealed reactor volume with a mixture of carbon powder and lithium containing powder, wherein the powder mixture is electrically conductive, and fill chlorine gas inside the sealed reactor. Step 2: Apply joule heating to the powder mixture (optionally moving the powder) resulting in producing gases, condensed matter, and / or solid lithium secondary products. During this step, depending on the process temperatures, the carbon may be graphitized or converted to graphite or graphene. Optionally, the carbon powder is not converted to graphene or graphite, or the carbon powder crystallinity is not substantially changed. Step 3: Collect at least partially the resulting lithium secondary products (gases, condensed matter, and / or solids) from the mixture. Step 4: Optionally, additional lithium powder and / or chlorine gas may be added and mixed to the reactor to increase the efficiency of the conversion process and / or to operate the process in a continuous mode.

[0142] Similar prior art disclosed by Deng, B. et al. (Flash separation of metals by electrothermal chlorination. Nat Chem Eng 1, 627-637, 2024) describes a method for selective separation of individual critical metals from electronic waste, in particular, selective separation of individual critical metals from electronic waste, wherein the waste metal oxides and carbon source, are loaded on top of a carbon paper, under an atmosphere of Ch (chlorine gas), wherein the carbon paper is Joule heated to about 400°C to 2400°C, which in turn heats the metal oxides via conductive heat transfer to thermally convert them into metal chlorides. Again, this prior art does not disclose direct Joule heating of an electrically conductive powder mixture that comprises metal oxides powder as it is disclosed here.

[0143] To overcome the limitations of the prior art methods for metal recovery and separation, this invention discloses a method where the metal oxide comprising material, inpowder form, is mixed with at least one electrically conductive carbon powder and chlorinating agent powder to make an electrically conductive powder mixture that can be Joule heated directly as three-dimensional volume of powder with any of the exemplary reactors of Figures 2 to 10 described in this disclosure. Exemplary metals oxides that may be used to extract critical metals include but are not limited to ln2O3, SnO2, MnO, Cr2O3, Ta2O3, CuO, NiO. Exemplary metals that may be extracted with the novel method include but are not limited to Au, In, Sn, Mn, Cr, Mg, Sb, Na, Zn, Cu, Ta, Ag, Pb, Ba, Ti.

[0144] The methods for metal recovery and separation are analogous to the methods disclosed in Figure 5A (chlorinating agent powder) and Figure 5B (with chlorine gas) wherein the feedstock (starting material) is different and the rest of the process steps are the same.

[0145] While the above description provides examples of various apparatuses, methods, and systems, other apparatuses, methods, or systems may be within the reasonable scope of the claims as interpreted by one of skill in the art.

Claims

CLAIMS:

1. A system for Joule heating comprising: a rotatable bucket for containing powder material, a set of electrodes inside the bucket, wherein the electrodes are fixed with respect to the bucket, the electrodes are capable of making contact with the powder material, and the electrodes are capable of mixing the powder material, wherein an electrical current can flow between the electrodes through the powder to Joule heat the powder material.

2. The system of Claim 1, wherein the bucket is a graphite bucket3. The system of Claim 2, wherein the graphite bucket comprises a ceramic bottom4. The system of Claim 1, wherein the bucket is a ceramic bucket5. The system of Claim 4, wherein the ceramic bucket is inserted into another larger bucket wherein the gap between the bucket and the large bucket is filled with thermally insulating material6. The system of Claim 5, wherein the thermally insulating material is one of sand, SiC powder, refractory powder, clay powder, concrete cast, refractive material cast, clay cast, or any combination thereof7. The system of Claim 1, wherein the bucket is sealed8. A system for Joule heating comprising: a rotatable graphite bucket for containing powder material,at least one electrode inside the bucket, wherein the at least one electrode is fixed with respect to the bucket, the at least one electrode is capable of making contact with the powder material, and the at least one electrode is capable of mixing the powder material, wherein an electrical current can flow from the at least one electrode to the graphite bucket through the powder to Joule heat the powder material.

9. The system of Claim 8, wherein the at least one electrode is a single electrode10. A system for Joule heating comprising: a rotatable graphite tube for containing powder material, wherein the rotatable graphite tube is slanted downwards, the rotatable graphite tube is capable of propelling powder material, at least one electrode inside the tube, wherein the at least one electrode is fixed with respect to the tube, the at least one electrode is capable making contact with the powder material, and the at least one electrode is capable of mixing the powder material, wherein an electrical current can flow from the at least one electrode to the rotatable graphite tube through the powder to Joule heat the powder material.

11. The system of Claim 10, wherein the at least one electrode is a single electrode12. The system of Claim 10, wherein the rotatable graphite tube is capable of propelling powder material using a rotational or rocking tube motion13. The system of Claim 10, wherein the system is capable of operating continuously14. A system for Joule heating comprising: a rotatable ceramic tube for containing powder material, wherein the rotatable ceramic tube is slanted downwards, the rotatable ceramic tube is capable of propelling powder material, a set of electrodes inside the tube, wherein the set of electrodes is fixed with respect to the tube, the set of electrodes is capable of making contact with the powder material, and the set of electrodes is capable of mixing the powder material, wherein an electrical current can flow between electrodes of the set through the powder to Joule heat the powder material.

15. A system for Joule heating comprising: a graphite box for containing powder material, a single rotatable electrode inside the box, wherein the electrode is capable of making contact with the powder material, and the electrode is capable of mixing the powder material, the electrode is capable of propelling the powder material downward, wherein an electrical current can flow from the electrode to the graphite box through the powder to Joule heat the powder material.

16. The system of Claim 15, wherein the powder material can be inserted from the top of the graphite box17. The system of Claim 15, wherein the powder material can be removed from the bottom of the graphite box17. The system of Claim 15, wherein the system is capable of operating continuously18. The system of Claim 15, wherein the bucket is sealed19. The system of Claim 15, wherein the electrode may be cylindrical, oval, flared, having one or more fins, and any combination thereof20. The system of Claim 15, wherein the electrical current flow changes with the position of the rotating electrode21. A system for Joule heating comprising: a graphite box for containing powder material, a single electrode inside the box, wherein the electrode is capable of making contact with the powder material, and wherein an electrical current can flow from the electrode to the graphite box through the powder to Joule heat the powder material.

22. A method comprising:Joule heating electrically conductive powder mixture inside a reactor, wherein the reactor comprises stationary electrode pair in contact with the electrically conductive powder mixture, mixing the electrically conductive powder mixture while Joule heating,wherein the reactor is moved with respect to the stationary electrode pair. changing at least one material property of at least one of the components of the powder mixture.

23. The method of Claim 22 wherein the electrically conductive powder mixture comprises carbon.

24. The method of Claim 23, wherein the carbon includes at least one of: anthracite coal, green petroleum coke, asphaltenes, recycled-tire carbon black, bio char, wood char, plant char, paralyzed cellulose, conductive polymer, conductive plastic, plastic char, plastic ash.

25. The method of Claim 23, wherein the carbon includes at least one of: calcinated petroleum coke, metallurgical coke, amorphous carbon, carbon black, activated carbon, char, graphene, flash graphene, carbon nanotubes, carbon nanofibers, carbon fiber, graphitized carbon fiber.

26. The method of Claim 22, wherein the mixing can be continuous or intermittent.

27. The method of Claim 22 wherein changing at least one material property of the electrically conductive powder mixture includes change of the material's crystallinity.

28. The method of claim 27 wherein the material component includes carbon, silica, plastics, and their combination thereof.

29. The method of Claim 28, wherein the carbon with changed crystallinity includes at least one of graphitized carbon, crystalline carbon, graphene, turbostratic graphene, graphite, turbostratic graphite, AB stacked graphite, ABC stacked graphite, carbon nanotubes, and nanofibers.

30. The method of Claim 28, wherein the carbon crystallinity is not substantially changed.

31. The method of Claim 28, wherein the carbon crystallinity is substantially changed.

32. The method of Claim 22 wherein the mixture comprises non-electrically conductive materials.

33. The method of Claim 32 wherein the mixture includes plastic.

34. The method of Claim 22 wherein the material component includes carbon and silica35. The method of Claim 34 wherein the material mixture is at least some of it converted to silicon carbide

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