Repurposing of spent activated carbon

Abstract

A method for repurposing spent activated carbon includes introducing the spent activated carbon including one or more sorbed materials into a high-temperature industrial process to repurpose carbon content in the spent activated carbon.

Description

4820.035W01REPURPOSING OF SPENT ACTIVATED CARBONCROSS-REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of priority to U.S. Provisional Patent Application Serial No. 63 / 733,654 filed Dec. 13, 2024, the disclosure of which is incorporated herein in its entirety by reference.BACKGROUND

[0002] Activated carbon (AC) is a widely used material produced from carbonaceous sources like bamboo, coconut husk, willow peat, wood, coir, lignite, coal, and petroleum pitch. The production process involves physical and / or chemical activation at high temperatures such as 1112 °F to 1652 °F (600-900 °C) using gases like steam and CO2 to create a highly porous material. Two primary forms of activated carbon are commonly used in industrial applications: powdered activated carbon (PAC) and granular activated carbon (GAC). PAC consists of fine particles typically less than one millimeter in size, while GAC has larger particle sizes and is commonly used in filtration applications. Both PAC and GAC are extensively used to remove harmful contaminants from gas, vapor, and liquid streams. These contaminants include hydrocarbons, dissolved organic materials, chlorinated hydrocarbons, heavy metals, solvents, pharmaceutical products, pesticides, and per- and polyfluoroalkyl substances (PFAS). After being used to remove these contaminants, activated carbon becomes “spent activated carbon” containing various captured contaminants. Currently, spent activated carbon is typically either thermally reactivated or disposed of in landfills. The steel industry, which requires carbon for both charge carbon and injection carbon in steelmaking processes, presents an opportunity for beneficial reuse of spent activated carbon.

[0003] The steel manufacturing process, particularly in electric arc furnaces (EAF) which now account for over 70 percent of steel production in the United States, requires significant amounts of carbon for various purposes including increasing carbon content in steel, improving molten steel quality, and reducing energy consumption. Similarly, the growing demand for graphite, particularly in electric vehicle batteries, has created supply challenges. By 2030, natural graphite is projected to face significant supply shortfalls of approximately 1.2 million metric tons. This increasing demand for graphite, combined with the need for sustainable disposal solutions for spent activated carbon, creates an opportunity for innovative reuse approaches. The current challenges in spent activated carbon disposal,4820.035W01 combined with the increasing demand for carbon materials in steel production and graphite manufacturing, highlight the need for new methods to beneficially reuse spent activated carbon while ensuring the safe destruction of captured contaminants.SUMMARY OF THE INVENTION

[0004] Various aspects of the present disclosure provide a method for repurposing spent activated carbon. The method includes introducing spent activated carbon including one or more sorbed materials into a high-temperature industrial process to repurpose carbon content in the spent activated carbon.

[0005] Various aspects of the present disclosure provide a method for treating spent activated carbon including one or more sorbed materials. The method includes introducing the spent activated carbon into a high-temperature industrial process operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0006] Various aspects of the present disclosure provide a method for treating spent activated carbon including one or more sorbed PFAS compounds. The method includes introducing the spent activated carbon into a high-temperature industrial process operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed PFAS compounds.

[0007] Various aspects of the present disclosure provide a method for steel production. The method includes using spent activated carbon including one or more sorbed materials in steelmaking as charge carbon and / or injection carbon sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0008] Various aspects of the present disclosure provide a method for producing coke. The method includes heating spent activated carbon in the absence of oxygen, the spent activated carbon including one or more sorbed materials, to produce coke, wherein the heating is sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0009] Various aspects of the present disclosure provide a method for producing graphite. The method includes converting spent activated carbon including one or more sorbed materials to coke sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials. The method also includes processing the coke to produce graphite with 1 wt% to 99 wt% purity.

[0010] Various aspects of the present disclosure provide a system for repurposing spent activated carbon. The system includes a receiving facility for spent activated carbon4820.035W01 including one or more sorbed materials. The system includes processing, transport, or handling equipment for introducing the spent activated carbon into a high-temperature industrial process.

[0011] Various aspects of the methods and systems of the present disclosure have certain advantages over other methods and systems for repurposing or treating activated carbon. For example, the methods and systems of various aspects of the present disclosure can provide environmental advantages. For example, the methods and systems of various aspects of the present disclosure can provide an alternative to landfill disposal of spent activated carbon. The methods and systems of various aspects of the present disclosure can potentially reduce greenhouse gas emissions when using biomass-derived spent activated carbon as charge or injection carbon in steelmaking. The methods and systems of various aspects of the present disclosure can enable destruction of harmful contaminants captured in spent activated carbon through high-temperature processes, particularly in steelmaking where temperatures exceed 2,800 °F.

[0012] The methods and systems of various aspects of the present disclosure can provide various process or technical advantages. For example, the methods and systems of various aspects of the present disclosure can offer flexibility in usage amounts, as spent activated carbon can be mixed with charge or injection carbon, or mixed with conventional starting materials for coke production or graphite production, in proportions ranging from 0- 100%. The methods and systems of various aspects of the present disclosure can create a high-carbon content feedstock for coke production, benefiting from the fact that spent activated carbon has already undergone initial thermal processing to remove volatile matter. The methods and systems of various aspects of the present disclosure can enable tailoring of coke products for specific graphite manufacturing requirements, with the ability to produce low-to-medium-high purity (1-99%) graphite products. The methods and systems of various aspects of the present disclosure can offer multiple pathways for processing and treating spent activated carbon through various methods including thermal processes, chemical reactions, biological reactions, and mechanical means. The methods and systems of various aspects of the present disclosure can allow for enhancement of end products through the addition of various materials to the spent activated carbon, including organics, inorganics, metals, and clay-based materials.

[0013] The methods and systems of various aspects of the present disclosure can provide various economic or supply chain advantages. For example, the methods and systems of various aspects of the present disclosure can provide a solution to address4820.035W01 projected graphite supply shortfalls, particularly important for electric vehicle battery production. The methods and systems of various aspects of the present disclosure can create potential cost benefits by repurposing a waste material (spent activated carbon) into valuable industrial feedstock. The methods and systems of various aspects of the present disclosure can support the steel industry’s need for carbon while providing an environmentally responsible disposal method. Various aspects of the method and system of the present disclosure avoid the costs of disposing of spent activated carbon in an environmentally friendly way and instead generate of benefit of using the spent activated carbon as an alternative feedstock for high-temperature industrial processes. Various aspects of the method and system of the present disclosure provide a method to remove and destroy contaminants on / within spent activated carbon rather than creating an environmental disposal concern or harm, while also providing a beneficial use to industries that use coke products, such as the steel and graphite making industry.

[0014] The methods and systems of various aspects of the present disclosure can provide various product customization advantages. For example, the methods and systems of various aspects of the present disclosure can provide flexibility in end-product specifications through various treatment and additive options. The methods and systems of various aspects of the present disclosure can enable customization based on specific industrial needs through different processing methods and additives.

[0015] The methods and systems of various aspects of the present disclosure can allow for mixing spent activated carbon in various proportions in real time to better control or improve the efficiency of the high-temperature process and to produce a more consistent quality product over time. In various aspects, the spent activated carbon can have fewer or a lower concentration of impurities than the carbon source normally used for charge or injection carbon, or for coking; the methods and systems of various aspects of the present disclosure can provide higher quality products from the high-temperature process by virtue of the higher purity of the spent activated carbon compared to conventional starting materials for the high-temperature process.BRIEF DESCRIPTION OF THE FIGURES

[0016] The drawings illustrate generally, by way of example, but not by way of limitation, various aspects of the present disclosure.

[0017] FIG. 1 illustrates basic oxygen steelmaking and electric arc furnace steelmaking, in accordance with various aspects of the present disclosure.4820.035W01

[0018] FIG. 2 illustrates basic oxygen steelmaking and electric arc furnace steelmaking, in accordance with various aspects of the present disclosure.

[0019] FIG. 3 illustrates a microscopic view of “green” carbon graphite, in accordance with various aspects of the present disclosure.

[0020] FIG. 4 illustrates a microscopic view of carbon graphite that has been sent through a baking process, in accordance with various aspects of the present disclosure.

[0021] FIG. 5 illustrates two microscopic views of graphite, with the left side illustrating plain carbon graphite, and with the right side illustrating plain graphite, in accordance with various aspects of the present disclosure.DETAILED DESCRIPTION OF THE INVENTION

[0022] Reference will now be made in detail to certain aspects of the disclosed subject matter. While the disclosed subject matter will be described in conjunction with the enumerated claims, it will be understood that the exemplified subject matter is not intended to limit the claims to the disclosed subject matter.

[0023] Throughout this document, values expressed in a range format should be interpreted in a flexible manner to include not only the numerical values explicitly recited as the limits of the range, but also to include all the individual numerical values or sub-ranges encompassed within that range as if each numerical value and sub-range is explicitly recited. For example, a range of “about 0.1% to about 5%” or “about 0.1% to 5%” should be interpreted to include not just about 0.1% to about 5%, but also the individual values (e.g., 1%, 2%, 3%, and 4%) and the sub-ranges (e.g., 0.1% to 0.5%, 1.1% to 2.2%, 3.3% to 4.4%) within the indicated range. The statement “about X to Y” has the same meaning as “about X to about Y,” unless indicated otherwise. Likewise, the statement “about X, Y, or about Z” has the same meaning as “about X, about Y, or about Z,” unless indicated otherwise.

[0024] In this document, the terms “a,” “an,” or “the” are used to include one or more than one unless the context clearly dictates otherwise. The term “or” is used to refer to a nonexclusive “or” unless otherwise indicated. The statement “at least one of A and B” or “at least one of A or B” has the same meaning as “A, B, or A and B.” In addition, it is to be understood that the phraseology or terminology employed herein, and not otherwise defined, is for the purpose of description only and not of limitation. Any use of section headings is intended to aid reading of the document and is not to be interpreted as limiting; information that is relevant to a section heading may occur within or outside of that particular section.4820.035W01

[0025] In the methods described herein, the acts can be carried out in a specific order as recited herein. Alternatively, in any aspect(s) disclosed herein, specific acts may be carried out in any order without departing from the principles of the disclosure, except when a temporal or operational sequence is explicitly recited. Furthermore, specified acts can be carried out concurrently unless explicit claim language recites that they be carried out separately or the plain meaning of the claims would require it. For example, a claimed act of doing X and a claimed act of doing Y can be conducted simultaneously within a single operation, and the resulting process will fall within the literal scope of the claimed process.

[0026] The term “about” as used herein can allow for a degree of variability in a value or range, for example, within 10%, within 5%, or within 1% of a stated value or of a stated limit of a range, and includes the exact stated value or range.

[0027] The term “substantially” as used herein refers to a majority of, or mostly, as in at least about 50%, 60%, 70%, 80%, 90%, 95%, 96%, 97%, 98%, 99%, 99.5%, 99.9%, 99.99%, or at least about 99.999% or more, or 100%. The term “substantially free of’ as used herein can mean having none or having a trivial amount of, such that the amount of material present does not affect the material properties of the composition including the material, such that about 0 wt% to about 5 wt% of the composition is the material, or about 0 wt% to about 1 wt%, or about 5 wt% or less, or less than, equal to, or greater than about 4.5 wt%, 4, 3.5, 3, 2.5, 2, 1.5, 1, 0.9, 0.8, 0.7, 0.6, 0.5, 0.4, 0.3, 0.2, 0.1, 0.01, or about 0.001 wt% or less, or about 0 wt%.

[0028] As used herein, the term “polymer” refers to a molecule having at least one repeating unit and can include copolymers.4820.035W01Method for repurposing spent activated carbon.

[0029] Various aspects of the present disclosure provide a method for repurposing spent activated carbon. The method can include introducing the spent activated carbon into a high-temperature industrial process to repurpose carbon content in the spent activated carbon. The spent activated carbon can include one or more sorbed materials. The repurposing of the spent activated carbon including repurposing the carbon content in the spent activated carbon can include using the spent activated carbon to form any suitable product of the high- temperature industrial process that has a different purpose than the activated carbon; for example, a product having a non-sorbent purpose or use, such as steel, coke, graphite, or other non-sorbent products. The one or more sorbed materials are materials captured (e.g., sorbed, such as absorbed and / or adsorbed) by the activated carbon. In various aspects, the high-temperature industrial process can destroy some or all of the one or more sorbed materials in the spent activated carbon. In some aspects, the high-temperature industrial process can leave some or all of the one or more sorbed materials in the spent activated carbon intact (i.e., preserving the original chemical structure of the one or more sorbed materials).

[0030] The spent activated carbon can be any suitable spent activated carbon. The spent activated carbon can include a powdered activated carbon. The spent activated carbon can include a granulated activated carbon. The spent activated carbon can include a mixture of powdered activated carbon and granulated activated carbon. The spent activated carbon can include a monolithic three-dimensional form of activated carbon. The spent activated carbon can include an activated carbon filter. The spent activated carbon can include a pelletized activated carbon. The spent activated carbon can be part of a composite of activated carbon and another material, such as wherein the other material is ceramic. The spent activated carbon can include any suitable carbonaceous material or product that has undergone an activated process and subsequently been used to remove contaminants.

[0031] Activated carbon (AC) can be produced from carbonaceous source materials such as bamboo, coconut husk, willow peat, wood, coir, lignite, coal, and petroleum pitch. The activation of carbon within these sources is generally by physical and / or chemical activation under high temperatures using various gases such as steam and CO2. The source material can be subjected to high temperatures generally in the range of 1112 °F to 1652 °F (600-900 °C) to pyrolyze / carbonize the material to remove most of the volatile chemicals leaving behind primarily carbon and remaining inorganic material (e.g., sometimes referred to ash). The carbonized material can then be activated by exposing it to an oxidizing4820.035W01 environment (e.g., steam, oxygen, carbon dioxide, or a combination thereof) for some time period (minutes to hours) usually at temperatures above 482 °F to 572 °F (250-300 °C), more generally in the range of 1112 °F to 2192 °F (600-1200 °C). Activation using different oxidizing agents such as steam and CO2 has produced activated carbons with different porosities, pore densities, and surface and structural properties. For example, carbon dioxide activation typically leads to the creation of narrower pores compared to steam activation, as carbon dioxide activation primarily develops microporosity while steam activation tends to widen the micropores and create more mesopores, resulting in larger pore sizes overall.

[0032] Activation of source materials can also occur by adding / impregnating the material with various acids and / or strong base chemicals. Common impregnating chemicals used for activated carbon are phosphoric acid, potassium hydroxide, sodium hydroxide, potassium carbonate, calcium chloride, potassium permanganate, silver, copper oxide, zeolites, alumina, or a combination thereof. The impregnated carbon material can then be subjected to high temperatures (e.g., 482 °F to 1112 °F (250-600 °C)). Chemical activation may be preferable because lower activation temperatures and shorter time is needed to produce activated carbons that are of good quality with consistent properties.

[0033] There are generally two types of activated carbons defined based on the size of the AC particles, how they are prepared, and how they are used in industrial applications. These two types are most often referred to as powdered activated carbon (PAC) and granular activated carbon (GAC). PAC, GAC, and in general activated carbon are often referred to simply as carbons.

[0034] PAC is a fine powder typically less that one millimeter in size made from crushed, ground, or milled activated carbon material. PAC particles can range from 0.001 millimeter to one millimeter in size, but more commonly applied with an average particle size range of 0.01-0.2 millimeter. PAC is generally added directly into and moves with process flow streams such as flue gas, process gases, slurries, water streams, water intakes, basins, clarifies, gravity separation filters, and the like. Powdered activated carbon can have any suitable particle size. For example, the powdered activated carbon can have a dso particle size, a dgo particle size, or a sieve size, in the range of 1 microns to less than 200 microns, or 15 microns to 100 microns, or less than 200 microns and greater than or equal to 1 micron and less than, equal to, or greater than 2 microns, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, or 190 microns; because the sizes listed are dso particle size, a dw particle size, or sieve size, in various some of the particles can also have a particle size that is below 1 micron or greater than 200 microns,4820.035W01 while in other aspects the particle sizes are confined between 1 micron and 200 microns. Powdered activated carbon can have a minimum sieve size through which the material passes of in the range of 1 microns to less than 200 microns, or 15 microns to 100 microns, or less than 200 microns and greater than or equal to 1 micron and less than, equal to, or greater than 2 microns, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, or 190 microns. Powdered activated carbon can have a maximum sieve size through which the material passes of in the range of 1 microns to less than 200 microns, or 15 microns to 100 microns, or less than 200 microns and greater than or equal to 1 micron and less than, equal to, or greater than 2 microns, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 30, 40, 50, 60, 70, 80, 90, 100, 110, 120, 130, 140, 150, 160, 170, 180, or 190 microns.

[0035] GAC has a relatively larger particle size and smaller external surface (because of larger particle size) compared to PAC. GAC can be designed with open pores structures to allow for rapid diffusion through the particles for maximum adsorption of contaminants from gases, vapors, liquids. GAC can be manufactured in granular, extruded, or pelletized form and is generally used in air / gas filtration and water treatment facilities to separate and remove contaminants from and deodorize various flow streams. GAC can be designated by sizes such as 8x20, 20x40, or 8x30 for liquid phase applications and 4x6, 4x8 or 4x 10 for vapor phase applications. A 20x40 carbon is made of particles that will pass through a U.S. Standard Mesh Size No. 20 sieve (0.84 mm) (generally specified as 85% passing) but be retained on a U.S. Standard Mesh Size No. 40 sieve (0.42 mm) (generally specified as 95% retained). Most popular aqueous-phase carbons are the 12x40 and 8x30 sizes because they have a good balance of size, surface area, and head loss (pressure drop) characteristics. GAC can have any suitable particle size. For example, granulated activated carbon can have a dso particle size, a dw particle size, or a sieve size, in the range of 0.2 mm to 8 mm, or 0.2 mm to 5 mm, or less than or equal to 8 mm and greater than or equal to 0.2 mm and less than, equal to, or greater than 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or 7.5 mm. Granular activated carbon can have a minimum sieve size through which the material passes of 0.2 mm to 8 mm, or 0.2 mm to 5 mm, or less than or equal to 8 mm and greater than or equal to 0.2 mm and less than, equal to, or greater than 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or 7.5 mm. Granular activated carbon can have a maximum sieve size through which the material passes of 0.2 mm to 8 mm, or 0.2 mm to 5 mm, or less than or equal to 8 mm and greater than or equal to 0.2 mm and less than, equal to, or greater than 0.3, 0.4, 0.5, 0.6, 0.7, 0.8, 0.9, 1, 1.2, 1.4, 1.6, 1.8, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, or 7.5 mm.4820.035W01

[0036] PAC, GAC, or a combination thereof can be used to remove harmful or unwanted chemicals (contaminants) from gas, vapor, and liquid streams such as: contaminants that cause unwanted taste, odor or color; hydrocarbons; dissolved organic materials (e.g., atrazine, glyphosate, trichloroethylene, and tetrachloroethylene); chlorinated hydrocarbons; inorganic chemicals heavy metals (e.g. mercury, lead, arsenic, nitrates, and nitrites); solvents; disinfection byproducts (e.g., chloroform); endocrine-disrupting compounds; pharmaceutical product contamination; personal-care products contamination; pesticides; and per- and poly-fluoroalkyl substances (PF AS, e.g., perfluorooctane sulfonate (PFOS) or perfluorooctanoic acid (PFOA)).

[0037] GAC can be used to remove unwanted chemicals, tastes, and odors from water and air by capturing contaminants onto its large surface area (internal and external), making it a common component in water treatment systems and air purification filters; it can be particularly effective against organic compounds like pesticides, solvents, and chlorine. GAC can be used as a primary means of separating contaminant from streams or as a polishing / finishing step to ensure that contaminants are effectively removed to extremely low concentrations. As contaminated water or gas flows through GAC, contaminants sorb (adsorb and / or absorb) to the GAC surface and are removed. GAC can capture (remove) a wide range of contaminants such as organics, fuel oil, solvents, polychlorinated biphenyls (PCBs), dioxins, mercury, metals, and other industrial chemicals, as well as radioactive materials. More recently, PAC and GAC have been used to remove perfluoroalkyl and polyfluoroalkyl substances, or PF AS, generalized as forever chemicals. These harmful chemicals have been made since the 1950s and are now regulated by EPA.

[0038] Granular activated carbon (GAC) is the most widely used and well-established treatment technology for the removal of per- and polyfluoroalkyl substances (PF AS) contaminants from drinking water and wastewater. After the GAC has been exposed to contaminants for a period of time sufficient to capture the contaminants, it becomes a spent activated carbon. Thermal processes can be used to volatize and destroy contaminants from the spent activated carbon. Reactivation and regeneration are common practices to restore spent activated carbon back to its near-virgin state so that it can be reused. Both processes can be done using thermal processes albeit at different temperature. Regeneration generally can be done at lower temperatures below 932 °F (500 °C) whereas reactivation can be done at elevated temperature, generally above 1292 °F (700 °C).

[0039] Various aspects of the present disclosure focus on repurposing spent activated carbon (e.g., PAC, GAC, AC, activated carbon filters, and the like) for other beneficial4820.035W01 purposes and applications. Various aspects of the present disclosure also destroy contaminants that are on the spent activated carbon that may cause health and environmental concerns. In the context of the present disclosure, a spent activated carbon can be an activated carbon that has been used to remove / collect some form and amount of contaminant and therefore contains some amount of contaminant (e.g., one or more sorbed materials).

[0040] In various aspects the method of repurposing the spent activated carbon can destroy some or all of the one or more sorbed materials in the spent activated carbon. Destroying can include any suitable transformation of the chemical structure of a sorbed material (e.g., contaminant) such that the destroyed sorbed material has a different structure than the original sorbed material. Destroying the one or more sorbed materials can include transforming the chemical structure of the one or more sorbed materials, converting the one or more sorbed materials to one or more materials having a different chemical structure, converting the one or more sorbed materials to one or more materials that are less toxic or harmful to humans or animals, pyrolyzing the one or more sorbed materials, or a combination thereof. The use of the spent activated carbon in the high-temperature industrial process can be sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%.

[0041] The one or more sorbed materials in and / or on the spent activated carbon can be any suitable one or more sorbed materials. The one or more sorbed materials can include one or more chosen from a taste-affecting compound, an odor-affecting compound, a coloraffecting compound, a hydrocarbon, an organic material, atrazine, glyphosate, trichloroethylene, tetrachloroethylene, a chlorinated hydrocarbon, a heavy metal, mercury, lead, arsenic, a nitrate, a nitrite, a solvent, a disinfection byproduct, chloroform, an endocrine- disrupting compound, a pharmaceutical compound, a pharmaceutical manufacturing byproduct, a personal -care product compound, a pesticides, a per- or poly-fluoroalkyl substance (PFAS), a polychlorinated biphenyl (PCB), a dioxin, a radioactive material, a fuel oil, and an industrial chemical.

[0042] The one or more sorbed materials can include a per- or poly-fluoroalkyl substance (PFAS), wherein the PFAS is a perfluoroalkyl substance, a polyfluoroalkyl substance, or a perfluoroalkyl acid (PFAA). The one or more sorbed materials can include a per- or poly-fluoroalkyl substance (PFAS), wherein the PFAS is perfluorooctanesulfonic acid4820.035W01(PFOA), perfluorooctyl sulfonate (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorobutanesulfonic acid (PFBS), 2-(N-m ethylperfluorooctane sulfonamido) acetic acid, perfluoroheptanoic acid (PFHpA), n- perfluorooctane sulfonic acid, perfluoromethylheptane sulfonic acid, n-perfluorooctanoic acid, a branched perfluorooctanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, or a combination thereof.

[0043] In various aspects, the method of repurposing spent activated carbon includes adding the spent activated carbon to the high-temperature industrial process without any additives. In various aspects, the method further includes adding one or more materials to the spent activated carbon prior to or during the introducing of the spent activated carbon into the industrial process. The one or more materials can be any suitable one or more materials. In various aspects, the one or more added materials enhance performance of the spent activated carbon in the industrial process. The one or more added materials can include one or more of organics, metals, alkali materials, alkaline materials, clay-based materials, acids, and salts. The one or more added materials can include one or more of copper, chrome, manganese, magnesium, lime, limestone, trona, halides, halide salts, bentonite, kaolinite, montmorillonite, smectite, illite, chlorite, vermiculite, talc, and pyrophyllite. The one or more added materials can include one or more organic additives including at least one chosen from a sugar, a fat, a protein, a carbohydrate, DNA, cellulose, chlorophyll, an enzyme, a hormone, a vitamin, petroleum, natural gas, and a food item. The one or more added materials can include one or more materials chosen from a binder, a sulfonate, a starch, and a coal tar pitch. The one or more added materials can form any suitable proportion of the overall amount of spent activated carbon and one or more added materials added to the high-temperature industrial process, such as 0.01 wt% to 99 wt%, or 0.1 wt% to 50 wt%, or 0.1 wt% to 10 wt%, or less than or equal to 99 wt% and greater than or equal to 0.01 wt% and less than, greater than, or equal to 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, or 98 wt%.

[0044] The activated carbon used to form the spent activated carbon (e.g., via sorption of the one or more sorbed materials) can be derived from any suitable source. In various aspects, the activated carbon used to form the spent activated carbon can be derived from biomass. By deriving the activated carbon used to form the spent activated carbon from biomass, various aspects of the present disclosure can reduce greenhouse gas emissions compared to using a non-biomass-derived carbon source in place of the spent activated carbon. The biomass used to form the activated carbon can be any suitable biomass, such as4820.035W01 agricultural waste (e.g., corncobs, rice husks, fruit peels), wood products (e.g., sawdust, wood chips), plant fibers (e.g., cellulose-rich materials such as cotton stalks or bamboo), shell materials (e.g., coconut shells), cellulose, polymers, pitch, peat, or a combination thereof.The biomass used to form the activated carbon can include bamboo, coconut husk, willow peat, a wood product, coir, or a combination thereof.

[0045] In various aspects, the high-temperature industrial process can include steelmaking. The spent activated carbon can be used as charge carbon in the steelmaking process. In various aspects, the spent activated carbon can be used as charge carbon and can be mixed with conventional charge carbon. For example, the spent activated carbon can be 0.001 wt% to 100 wt% of the charge carbon, or 0.1 wt% to 50 wt%, or 0.1 wt% to 10 wt%, or less than or equal to 100 wt% and greater than or equal to 0.001 wt% and less than, greater than, or equal to 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, or 99.999 wt%.

[0046] The spent activated carbon can be used as injection carbon in the steelmaking process. In various aspects, the spent activated carbon can be used as injection carbon and can be mixed with conventional injection carbon. For example, the spent activated carbon can be 0.001 wt% to 100 wt% of the injection carbon, or 0.1 wt% to 50 wt%, or 0.1 wt% to 10 wt%, or less than or equal to 100 wt% and greater than or equal to 0.001 wt% and less than, greater than, or equal to 0.005, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, or 99.999 wt%. For example, the method can include using the spent activated carbon as injection carbon for slag foaming operations, wherein the method further includes producing carbon monoxide gas to foam slag via one or more reactions between the spent activated carbon and iron oxide.

[0047] The steelmaking process can operate at any suitable temperature sufficient for steelmaking. The steelmaking process can operate at or above a temperature sufficient to destroy some or all of the one or more sorbed materials, e.g., 50 wt% to 100 wt% of the one or more sorbed materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%. The steelmaking process can operate at or above a temperature in the range of about 500 °F (260 °C) to about 3,000 °F (1,649 °C), or 1,000 °F (537 °C) to about 2,000 °F (1,093 °C), or at least about4820.035W012,000 °F (1,093 °C), or at least about 2,800 °F (1,538 °C), or less than or equal to 1,650 °C and greater than or equal to 250 °C and less than, equal to, or greater than 260 °C, 280, 300, 320, 340, 360, 380, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, 1,350, 1,400, 1,450, 1,500, 1,550, or 1,600 °C.

[0048] Steel is made from iron ore, a compound of iron, oxygen and other minerals that occur in nature. Today there are two major commercial processes for making steel, namely basic oxygen steelmaking, which has liquid pig-iron from the blast furnace and scrap steel as the main feed materials, and electric arc furnace (EAF) steelmaking, which uses scrap steel or direct reduced iron (DRI) as the main feed materials.

[0049] FIGS. 1-2 illustrate basic oxygen steelmaking and electric arc furnace steelmaking. Blast furnaces are used as a first step in producing steel from iron oxides. Blast furnaces use coke, iron ore and limestone to produce pig iron. The use of EAFs has expanded and now accounts for over 70 percent of steel production in the United States. The EAF is different from the blast furnace as it produces steel by using an electrical current to melt scrap steel, direct reduced iron, and / or pig iron, to produce molten steel.

[0050] Carbon must be used in the steel making process to produce varying grades of steel. The amount of carbon added to the steel improves the hardness and strength of the steel, making it a more (or less) durable and ductile material. The carbons that are added at two different locations within the steel making process are referred to as “charge carbon” and “injection carbon.”

[0051] Charge carbon in steelmaking refers to the carbon added to the furnace during the initial charging process, conventionally in the form of coke or anthracite coal. The charge carbon is used to increase the carbon content of the molten steel and achieve the desired carbon content of the final steel product. The charge carbon further acts to remove oxygen from the iron oxide and also provides heat for the process. In comparison to injection carbon, the requirements for charge carbon are lower. Of particular interest are the heat content (e.g., calorific value), volatile matter, and inorganic (e.g., ash) content. A charge carbon with higher volatile matter and lower heat content will bum out rapidly adding to the necessary heat input for the process but will unlikely contribute to less carbon in the melt. With a favorable cost-benefit ratio, charge carbons with a lower heat content (e.g., lower carbon) and higher ash content can be used as long as the ash components are not detrimental to steel quality. Conversely, a charge carbon with lower volatile matter and higher heat content (e.g., higher carbon content) will bum more slowly contributing some to the heat input with more carbon dissolving and remaining in the melt.4820.035W01

[0052] Injection carbon is critical to slag foaming operations, which are necessary for high power furnace operations. Carbon injection is a critical step in steelmaking that involves introducing carbon into molten iron to increase its carbon content and raise the molten temperature. The process is carried out by injecting a controlled amount of carbon into the molten iron such as by using lances. In simple terms, the injection causes a chemical reaction that produces carbon monoxide gas, which rises to the surface and leaves behind a higher carbon content in the molten iron. That is, the carbon reacts with FeO to form CO and “foam” the slag. The foaming of the slag by CO / CO2 gas bubbles occurs in the EAF process via oxidation of carbon dissolved in the molten steel by oxides in the slag (reaction (1) below). This foaming process is enhanced and maintained by injecting appropriate amounts of carbon into the slag. The injected carbon can thereby react directly with the iron oxide according to reaction (2) or reduce the iron oxide indirectly according to reactions (3) and (4) via an intermediate gasification step.

[0053] Carbon injection is important for several reasons. For example, carbon injection allows the production of steel with a desired carbon level. Carbon injection can improve the quality of molten steel. Carbon injection can reduce the amount of energy consumed. Carbon injection can improve yield. Carbon injection can improve electrode consumption. Also, carbon injection can save or increase the life of refractory.

[0054] While others have identified alternative sources of carbon for the steel making process, they have not considered the use of spent activated carbon. Spent activated carbons have not been considered in the past because they contain undesirable chemicals (i.e., one or more sorbed materials, such as contaminants) that were thought to cause problems in the steel making process. Further, the one or more sorbed materials (e.g., contaminants) were thought to pose a risk of release to the environment and impacting the quality of the steel product. Various aspects of the present disclosure rely on the inventors’ understanding that high energy, high temperature processes can be used for the destruction of the one or more sorbed materials (e.g., contaminants). The steelmaking process can provide sufficiently high temperature conditions and sufficient residence time to destroy the one or more sorbed materials collected on / within the spent activated carbon while providing a beneficial use (e.g., energy and carbon) to the steel making process.4820.035W01

[0055] Further, if the spent activated carbon was originally produced from a carbon- neutral renewable energy source such as biomass, then the overall release of carbon dioxide (CO2) to the environment will be reduced if used as a charge or injection carbon. Thus, various aspects of the present disclosure not only identify an alternative use (or disposal) for spent activated carbons while also destroying contaminants, but also have the potential to reduce greenhouse gas emissions (e.g. CO2) from the steel industry.

[0056] As an aspect of the present disclosure, the amount of spent activated carbon mixed in with the charge or injection carbon can be between 1-100% of the charge and / or injection carbon (e.g., less than or equal to 100% and greater than or equal to 1% and less than, equal to, or greater than 2%, 3, 4, 5, 6, 8, 10, 12, 14, 16, 18, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 94, 95, 96, 97, 98, or 99%). Optimal amounts can be determined by steel quality, process conditions, cost-benefit analysis, and environmental factors. For example, depending on the form and amount, the impurities in the spent activated carbon may be beneficial or detrimental to the steel quality depending on process conditions.

[0057] In various aspects, the high-temperature industrial process can include coke production to form produced coke. The coke production can include one or more of: thermal processes, chemical reactions, biological reactions, size manipulation, mechanical reduction, density separation, reshaping, geometric shaping, and froth flotation. Any suitable proportion of the produced coke starting materials can be the spent activated carbon. For example, the spent activated carbon can be 0.001 wt% to 100 wt% of the produced coke starting materials, or less than or equal to 100 wt% and greater than or equal to 0.001 wt% and less than, equal to, or greater than 0.005 wt%, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%.

[0058] The coke production process can operate at any suitable temperature sufficient for coke production. The coke production process can operate at or above a temperature sufficient to destroy some or all of the one or more sorbed materials, e.g., 50 wt% to 100 wt% of the one or more sorbed materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%. The coke production process can operate at a temperature that is at or above about 1,500 °F (816 °C) to about 3,000 °F (1,649 °C), or about 1,500 °F (816 °C) to about 2,000 °F (1,093 °C), or less4820.035W01 than or equal to 1,650 °C and greater than or equal to 800 °C and less than, equal to, or greater than 850 °C, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, 1,350, 1,400, 1,450, 1,500, 1,550, or 1,600 °C, with the heating performed under ambient atmosphere or in the absence of oxygen (e.g., such as in a gas having less than 5 vol% oxygen, 4%, 3%, 2%, 1%, 0.5%, 0.1%, 0.05%, or less than 0.001 vol% oxygen, such as under an inert gas). The coke production can include heating the spent activated carbon to approximately 1800 °F (982 °C) in the absence of oxygen.

[0059] In various aspects, the method of repurposing the spent activated carbon including using the spent activated carbon in a coke production process can also include screening the produced coke to a size of about 1-4 inches, or less than or equal to 10 inches and greater than or equal to 0.5 inches and less than, equal to, or greater than 1 inch, 1.5, 2, 2.5, 3, 3.5, 4, 4.5, 5, 5.5, 6, 6.5, 7, 7.5, 8, 8.5, 9, or 9.5 inches. In various aspects, the method can further include processing the produced coke to produce graphite with any suitable purity level, such as 1 wt% to 99 wt% purity.

[0060] In various aspects, the method of repurposing the spent activated carbon including using the spent activated carbon in a coke production process can include forming produced coke having a carbon content equal to or greater than 70 wt%, or 80 wt%, or 90 wt%, or equal to or greater than 60 wt%, 62, 64, 66, 68, 70, 72, 74, 76, 78, 80, 81, 82, 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.9, or 99.99 wt%.

[0061] Coke is a grey, hard, and porous coal -based fuel with a high carbon content. It can be made by heating coal or petroleum in the absence of oxygen. Coke is an important industrial product, used mainly in iron ore smelting, but also can be used as a fuel in stoves and forges.

[0062] The term “coke” usually refers to the product derived from low-ash and low- sulfur bituminous coal by a process called coking, described below. A similar product called petroleum coke, or pet coke, can be obtained from crude petroleum in petroleum refineries.

[0063] Coking is the process of heating coal in the absence of oxygen to a temperature above 600 °C (1,112 °F) to drive off the volatile components of the raw coal, leaving behind a hard, strong, porous material with a high carbon content called coke. Coke has a porous structure with a relatively large surface area allowing it to burn more rapidly and due to its high carbon content release more heat than the coal from which it was created.

[0064] While coal traditionally has been a key part of the coke-making process, other sources of carbon such as biomass have been used as feedstock material. The process of coking generally involves grinding the feedstock material (e.g., coal, biomass, coconut shells,4820.035W01 and the like) and then placing it into a hot vessel (oven, furnace, and the like) where it is heated to approximately 1800 °F in the absence of oxygen. As feedstock material is heated the volatile matter such as oil, tar, hydrogen, nitrogen and sulfur begin to evolve. The material remains heated at high temperature for several hours (e.g., 12-24 h) before being removed, cooled, and screened to 1-4 inches in size. The end coke product can have a carbon content of greater than 90% and can appear like a hard black rock with strong structural integrity.

[0065] An advantage of using spent activated carbon (PAC, GAC, and the like) as a feedstock material for the coking process is that it has already undergone a thermal process during its original creation, thereby removing most of the volatile matter. Thus, the carbon content of spent activated carbon is relatively high — a desirable characteristic of coke. However, spent activated carbons contain contaminants (e.g., one or more sorbed materials), which may not be desirable in coking products, and can be removed. Various aspects of the present disclosure include the removal and / or destruction of contaminant from the spent activated carbon.

[0066] Various aspects of the present disclosure providing coking with the removal and / or destruction of contaminants from the spent activated carbon to provide a high-quality coke product. Removal of moisture by drying, removal of inorganics (e.g., ash, metals, and the like), and destruction of contaminants (e.g., one or more sorbed materials) from spent activated carbon can be performed by conventional and inventive processes, or combinations thereof. These processes can include, but are not limited to, thermal processes (e.g. low-to- high temperatures); chemical reactions (e.g., use of additives); biological reactions; size manipulation and / or reduction by chemical and mechanical means; separation by mass, volume, density, viscosity, and the like using chemical and mechanical means; froth floatation; use of additives; or a combination thereof.

[0067] Various aspects of the present disclosure include adding materials to the spent activated carbon such that when combined enhance the quality of the coke product and destruction of contaminants. Further, additives may be added to the spent activated carbon to improve the quality of the coke and facilitate the destruction and fate of contaminants.

[0068] The size of the coke product can be of any size, small to large. A preferred aspect is a size of approximately 1-4 inches.

[0069] Various aspects of the present disclosure not only identify an alternative use (or disposal) for spent activated carbons (e.g., while also removing and destroying contaminants) but also provide a beneficial use to industries that use coke products, such as4820.035W01 the steel making industry. Often, spent activated carbons are landfilled. Various aspects of the present disclosure provide for an alternative to disposal while providing a beneficial product for industry and as a feedstock for the steel and graphite making process.

[0070] In various aspects, the high-temperature industrial process can include graphite production. Any suitable proportion of the graphite product starting materials can be the spent activated carbon. For example, the spent activated carbon can be 0.001 wt% to 100 wt% of the produced graphite starting materials, or less than or equal to 100 wt% and greater than or equal to 0.001 wt% and less than, equal to, or greater than 0.005 wt%, 0.01, 0.05, 0.1, 0.5, 1, 2, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 82, 84, 86, 88, 90, 91, 92, 93, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%.

[0071] The graphite production process can operate at any suitable temperature sufficient for graphite production. The graphite production process can operate at or above a temperature sufficient to destroy some or all of the one or more sorbed materials, e.g., 50 wt% to 100 wt% of the one or more sorbed materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%. The graphite production process can operate at a temperature that is at or above about 4,000 °F (2,204 °C) to 6,000 °F (3,315 °C), or about 5,000 °F (2,760 °C), or less than or equal to 3,350 °C and greater than or equal to 2,200 °C and less than, equal to, or greater than 2,250 °C, 2,300, 2,350, 2,400, 2,450, 2,500, 2,550, 2,600, 2,650, 2,700, 2,750, 2,800, 2,850, 2,900, 2,950, 3,000, 3,050, 3,100, 3,150, 3,200, 3,250, or 3,300 °C. The graphite production process can be performed under a controlled atmosphere. The atmosphere during graphite production can contain gases such as carbon dioxide (CO2), carbon monoxide (CO), oxygen, sulfur oxides (SOX), nitrogen oxides (NOX), volatile organic compounds (VOCs), hydrocarbons, or a combination thereof. This atmosphere can be controlled by removing and / or maintaining certain gases and maintaining appropriate levels of oxygen, carbon dioxide, carbon monoxide, argon, nitrogen, or a combination thereof. The graphite production process can hold the operating temperature for any suitable time, such as hours, days, or weeks, to allow for a desired purity of graphite (e.g., for the desired number of graphite layers), such as 1 minute to 6 weeks, or less than or equal to 6 weeks and greater than or equal to 1 minute and less than, equal to, or greater than 2 minutes, 3, 4, 5, 10, 15, 20, 25, 30, 35, 40, 45, 55 minutes, 1 hour, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 14, 16, 18, 20, 22 hours, 1 day, 1.5, 2, 3, 4, 5, 6 days, 1 week, 1.5, 2, 3, 4, or 5 weeks.4820.035W01

[0072] Because of its light weight, thermal, and electrical properties, graphite is increasingly being used in many applications including parts, bearings, lubricants, electrical components, batteries, and the like. There are two types of graphite: natural graphite which is mined, and synthetic graphite which is manufactured from carbon-based materials. The ever- increasing demand is leading to major supply shortages, especially with the increased number of electric vehicles projected for the future. By 2030, natural graphite is projected to have among the largest supply shortfalls of battery materials, with demand outstripping expected supplies by about 1.2 million metric tons.

[0073] Synthetic, or man-made, graphite is made from materials with a high carbon content such as coke. The coke that is produced as described above can be used as a starting feedstock.

[0074] Synthetic graphite can be produced through a process where a high carbon content substance (e.g., coke, petrochemicals, pitch, coal, acetylene, and the like) is heated at very high temperatures for long periods of time. In doing so the synthetic graphite can have a purity of over 99% carbon.

[0075] Carbon turns into graphite through a process called graphitization, which can require heating carbon-containing substances to high temperatures for hours to weeks. Binders such as coal tar pitch can be used to hold together individual carbon particles.During the baking process, outgassing of the binder occurs, meaning hydrocarbons in the pitch are driven off due to the extreme heat, leaving behind an amorphous carbon structure. During outgassing, these gasses push their way out of the material, leaving behind a network of interconnected porosity. FIG. 3 illustrates a microscopic view of “green” carbon graphite. FIG. 4 illustrates a microscopic view of carbon graphite that has been sent through a baking process.

[0076] The plain carbon graphite that is produced during this process can be a highly porous material, which can be impregnated with various added substances (e.g., additives) to enhance its properties specific to a given application.

[0077] Carbon graphite can be further processed to manufacture a purer form of graphite, thereby improving its thermal, electrical, and lubricity properties. During this process, carbon graphite can be heated to approximately 5,000 °F in a controlled atmosphere for long periods of time, such as days to over a week. Throughout this time, the amorphous carbon matrix that surrounds the graphite grains within the material begins to change form and become graphite. FIG. 5 illustrates two microscopic views of graphite, with the left side illustrating plain carbon graphite, and with the right side illustrating plain graphite. Plain4820.035W01 carbon graphite (left side) includes graphite grains embedded within a matrix of hard, amorphous carbon. Plain graphite (right side) does not have the same amorphous carbon matrix, but rather has a softer, more lubricious graphite matrix.

[0078] Various aspects of the present disclosure provide coke feedstock for graphite production from spent activated carbon.Method for treating spent activated carbon.

[0079] Various aspects of the present disclosure provide a method for treating spent activated carbon including one or more sorbed materials. The method destroys some or all of the one or more sorbed materials in the activated carbon.

[0080] A method for treating spent activated carbon including one or more sorbed materials can include introducing the spent activated carbon into a high-temperature industrial process (e.g., steelmaking, coke production, graphite production, or another high- temperature industrial process) operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials, such as 50 wt% to 100 wt% of the one or more sorbed materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt%. The high-temperature industrial process can operate at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C), or 500 °F (260 °C) to about 6,000 °F (3,316 °C), or 250 °F (121 °C) to about 2000 °F (1,093 °C), or about 500 °F (260 °C) to about 1200 °F (649 °C), or about 250 °F (121 °C) to about 1200 °F (649 °C), or less than or equal to 3,320 °C and greater than or equal to 120 °C and less than, equal to, or greater than 150 °C, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, 1,350, 1,400, 1,450, 1,500, 1,550, 1,600, 1,650, 1,700, 1,750, 1,800, 1,850, 1,900,1,950, 2,000, 2,050, 2,100, 2,150, 2,200, 2,250, 2,300, 2,350, 2,400, 2,450, 2,500, 2,550,2,600, 2,650, 2,700, 2,750, 2,800, 2,850, 2,900, 2,950, 3,000, 3,050, 3,100, 3,150, 3,200,3,250, or 3,300 °C.

[0081] A method for treating spent activated carbon including one or more sorbed PF AS compounds can include introducing the spent activated carbon into a high-temperature industrial process (e.g., steelmaking, coke production, graphite production, or another high- temperature industrial process) operating at or above a temperature in the range of about 2504820.035W01°F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed PF AS compounds, such as 50 wt% to 100 wt% of the one or more sorbed PFAS materials, or 70 wt% to 100 wt%, or 90 wt% to 100 wt%, or 99 wt% to 100 wt%, or less than or equal to 100 wt% and greater than or equal to 1 wt% and less than, equal to, or greater than 2 wt%, 3, 4, 5, 6, 8, 10, 15, 20, 25, 30, 35, 40, 45, 50, 55, 60, 65, 70, 75, 80, 85, 90, 92, 94, 95, 96, 97, 98, 99, 99.5, 99.9, 99.99, or 99.999 wt% of the sorbed PFAS materials. The high-temperature industrial process can operate at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C), or 500 °F (260 °C) to about 6,000 °F (3,316 °C), or 250 °F (121 °C) to about 2000 °F (1,093 °C), or about 500 °F (260 °C) to about 1200 °F (649 °C), or about 250 °F (121 °C) to about 1200 °F (649 °C), or less than or equal to 3,320 °C and greater than or equal to 120 °C and less than, equal to, or greater than 150 °C, 200, 250, 300, 350, 400, 450, 500, 550, 600, 650, 700, 750, 800, 850, 900, 950, 1,000, 1,050, 1,100, 1,150, 1,200, 1,250, 1,300, 1,350, 1,400, 1,450, 1,500, 1,550, 1,600,1,650, 1,700, 1,750, 1,800, 1,850, 1,900, 1,950, 2,000, 2,050, 2,100, 2,150, 2,200, 2,250,2,300, 2,350, 2,400, 2,450, 2,500, 2,550, 2,600, 2,650, 2,700, 2,750, 2,800, 2,850, 2,900,2,950, 3,000, 3,050, 3,100, 3,150, 3,200, 3,250, or 3,300 °C.

[0082] The method for treating spent activated carbon can include adding one or more added materials to the spent activated carbon prior to and / or during the introduction of the spent activated carbon to the high-temperature industrial process. The added material can be any suitable material. The added material can include one or more additives described herein. The added material can include one or more materials other than the one or more additives described herein. The high-temperature industrial process can be any suitable process, such as steelmaking, coke production, graphite production, or another process such as a high-temperature process for treating activated carbon for environmentally safe disposal.System for repurposing spent activated carbon.

[0083] Various aspects of the present disclosure provide a system that can perform one or more embodiments of the method of repurposing a spent activated carbon described herein. For example, various aspect of the present disclosure provide system for repurposing spent activated carbon that can include a receiving facility for spent activated carbon including one or more sorbed materials. The system can also include equipment for introducing the spent activated carbon into a high-temperature industrial process (e.g., steelmaking, coke production, graphite production, or another high-temperature industrial process), such as processing equipment, storage equipment, transport equipment, handling4820.035W01 equipment, or a combination thereof. In various aspects, the system can further include equipment for introducing added material to the spent activated carbon prior to or during the introduction of the spent activated carbon to the high-temperature industrial process. The added material can be any suitable material. The added material can include one or more additives described herein. The added material can include one or more materials other than the one or more additives described herein.

[0084] The terms and expressions that have been employed are used as terms of description and not of limitation, and there is no intention in the use of such terms and expressions of excluding any equivalents of the features shown and described or portions thereof, but it is recognized that various modifications are possible within the scope of the aspects of the present disclosure. Thus, it should be understood that although the present disclosure has been specifically disclosed by specific aspects and optional features, modification and variation of the concepts herein disclosed may be resorted to by those of ordinary skill in the art, and that such modifications and variations are considered to be within the scope of aspects of the present disclosure.

[0085] The following exemplary aspects are provided, the numbering of which is not to be construed as designating levels of importance:

[0086] Aspect 1 provides a method for repurposing spent activated carbon comprising: introducing the spent activated carbon comprising one or more sorbed materials into a high-temperature industrial process to repurpose carbon content in the spent activated carbon.

[0087] Aspect 2 provides the method of Aspect 1, wherein the spent activated carbon is any suitable activated carbon.

[0088] Aspect 3 provides the method of any one of Aspects 1-2, wherein the spent activated carbon is powdered activated carbon.

[0089] Aspect 4 provides the method of any one of Aspects 1-3, wherein the spent activated carbon is granulated activated carbon.

[0090] Aspect 5 provides the method of any one of Aspects 1-4, wherein the spent activated carbon is an activated carbon filter.

[0091] Aspect 6 provides the method of any one of Aspects 1-5, wherein the use of the spent activated carbon in the high-temperature industrial process is sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.4820.035W01

[0092] Aspect 7 provides the method of Aspect 6, wherein the use of the spent activated carbon in the high-temperature industrial process is sufficient to destroy 70 wt% to 100 wt% of the one or more sorbed materials.

[0093] Aspect 8 provides the method of any one of Aspects 6-7, wherein the use of the spent activated carbon in the high-temperature industrial process is sufficient to destroy 90 wt% to 100 wt% of the one or more sorbed materials.

[0094] Aspect 9 provides the method of any one of Aspects 6-8, wherein the use of the spent activated carbon in the high-temperature industrial process is sufficient to destroy 99 wt% to 100 wt% of the one or more sorbed materials.

[0095] Aspect 10 provides the method of any one of Aspects 6-9, wherein destroying the one or more sorbed materials comprises transforming the chemical structure of the one or more sorbed materials, converting the one or more sorbed materials to one or more materials having a different chemical structure, converting the one or more sorbed materials to one or more materials that are less toxic or harmful to humans or animals, pyrolyzing the one or more sorbed materials, or a combination thereof.

[0096] Aspect 11 provides the method of any one of Aspects 1-10, wherein the one or more sorbed materials comprise one or more chosen from a taste-affecting compound, an odor-affecting compound, a color-affecting compound, a hydrocarbon, an organic material, atrazine, glyphosate, trichloroethylene, tetrachloroethylene, a chlorinated hydrocarbon, a heavy metal, mercury, lead, arsenic, a nitrate, a nitrite, a solvent, a disinfection byproduct, chloroform, an endocrine-disrupting compound, a pharmaceutical compound, a pharmaceutical manufacturing byproduct, a personal-care product compound, a pesticides, a per- or poly-fluoroalkyl substance (PF AS), a polychlorinated biphenyl (PCB), a dioxin, a radioactive material, a fuel oil, and an industrial chemical.

[0097] Aspect 12 provides the method of any one of Aspects 1-11, wherein the one or more sorbed materials comprises a per- or poly-fluoroalkyl substance (PFAS), wherein the PFAS is a perfluoroalkyl substance, a polyfluoroalkyl substance, or a perfluoroalkyl acid (PFAA).

[0098] Aspect 13 provides the method of any one of Aspects 1-12, wherein the one or more sorbed materials comprises a per- or poly-fluoroalkyl substance (PFAS), wherein the PFAS is perfluorooctanesulfonic acid (PFOA), perfluorooctyl sulfonate (PFOS), perfluorohexanesulfonic acid (PFHxS), perfluorononanoic acid (PFNA), perfluorobutanesulfonic acid (PFBS), 2-(N-methyl-perfluorooctane sulfonamido) acetic acid, perfluoroheptanoic acid (PFHpA), n-perfluorooctane sulfonic acid, perfluoromethylheptane4820.035W01 sulfonic acid, n-perfluorooctanoic acid, a branched perfluorooctanoic acid, perfluorodecanoic acid, perfluoroundecanoic acid, perfluorododecanoic acid, or a combination thereof.

[0099] Aspect 14 provides the method of any one of Aspects 1-13, wherein the high- temperature industrial process comprises steelmaking.

[0100] Aspect 15 provides the method of Aspect 14, wherein the spent activated carbon is used as charge carbon in the steelmaking process.

[0101] Aspect 16 provides the method of any one of Aspects 14-15, wherein the spent activated carbon is used as injection carbon in the steelmaking process.

[0102] Aspect 17 provides the method of Aspect 16, wherein the spent activated carbon is used as injection carbon for slag foaming operations, wherein the method further comprises producing carbon monoxide gas to foam slag via one or more reactions between the spent activated carbon and iron oxide.

[0103] Aspect 18 provides the method of any one of Aspects 14-17, wherein the steelmaking process operates at or above a temperature in the range of about 500 °F (260 °C) to about 3,000 °F (1,649 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0104] Aspect 19 provides the method of any one of Aspects 14-18, wherein the steelmaking process operates at or above a temperature in the range of about 1,000 °F (537 °C) to about 2,000 °F (1,093 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0105] Aspect 20 provides the method of any one of Aspects 14-19, wherein the steelmaking process reaches temperatures of at least about 2,000 °F (1,093 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0106] Aspect 21 provides the method of any one of Aspects 14-20, wherein the steelmaking process reaches temperatures of at least about 2,800 °F (1,538 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0107] Aspect 22 provides the method of any one of Aspects 14-21, wherein the spent activated carbon is mixed with conventional charge or injection carbon in an amount of 0.001 wt% to 100 wt%.

[0108] Aspect 23 provides the method of any one of Aspects 1-22, wherein the high- temperature industrial process comprises coke production to form produced coke.

[0109] Aspect 24 provides the method of Aspect 23, wherein the coke production comprises one or more of: thermal processes,4820.035W01 chemical reactions, biological reactions, size manipulation, mechanical reduction, density separation, reshaping, geometric shaping, and froth flotation.

[0110] Aspect 25 provides the method of any one of Aspects 23-24, comprising heating the spent activated carbon to a temperature of about 1,500 °F (816 °C) to about 3,000 °F (1,649 °C).

[0111] Aspect 26 provides the method of any one of Aspects 23-25, comprising heating the spent activated carbon to a temperature of about 1,500 °F (816 °C) to about 2,000 °F (1,093 °C).

[0112] Aspect 27 provides the method of any one of Aspects 23-26, comprising heating the spent activated carbon to approximately 1800 °F (982 °C) in the absence of oxygen.

[0113] Aspect 28 provides the method of any one of Aspects 23-27, further comprising: screening the produced coke to a size of approximately 1-4 inches.

[0114] Aspect 29 provides the method of any one of Aspects 23-28, further comprising processing the coke to produce graphite with 1 wt% to 99 wt% purity.

[0115] Aspect 30 provides the method of any one of Aspects 1-29, wherein the high- temperature industrial process comprises graphite production.

[0116] Aspect 31 provides the method of Aspect 30, comprising heating the spent activated carbon to approximately 4,000 °F (2,204 °C) to 6,000 °F (3,315 °C) in a controlled atmosphere.

[0117] Aspect 32 provides the method of any one of Aspects 30-31, comprising heating the spent activated carbon to approximately 5,000 °F (2,760 °C) in a controlled atmosphere.

[0118] Aspect 33 provides the method of any one of Aspects 1-32, further comprising adding one or more materials to the spent activated carbon prior to or during the introducing of the spent activated carbon into the industrial process, wherein the one or more added materials enhance performance of the spent activated carbon in the industrial process.4820.035W01

[0119] Aspect 34 provides the method of Aspect 33, wherein the one or more added materials comprise one or more of organics, metals, alkali materials, alkaline materials, claybased materials, acids, and salts.

[0120] Aspect 35 provides the method of any one of Aspects 33-34, wherein the one or more added materials comprise one or more of copper, chrome, manganese, magnesium, lime, limestone, trona, halides, halide salts, bentonite, kaolinite, montmorillonite, smectite, illite, chlorite, vermiculite, talc, and pyrophyllite.

[0121] Aspect 36 provides the method of any one of Aspects 33-35, wherein the one or more added materials comprise one or more organic additives comprising at least one chosen from a sugar, a fat, a protein, a carbohydrate, DNA, cellulose, chlorophyll, an enzyme, a hormone, a vitamin, petroleum, natural gas, and a food item.

[0122] Aspect 37 provides the method of any one of Aspects 33-36, wherein the one or more added materials comprise one or more materials chosen from a binder, a sulfonate, a starch, and a coal tar pitch.

[0123] Aspect 38 provides the method of any one of Aspects 1-37, wherein activated carbon used to form the spent activated carbon is derived from biomass.

[0124] Aspect 39 provides the method of Aspect 38, wherein the method reduces greenhouse gas emissions compared to using a non-biomass-derived carbon source in place of the spent activated carbon.

[0125] Aspect 40 provides a method for treating spent activated carbon comprising one or more sorbed materials, the method comprising: introducing the spent activated carbon into a high-temperature industrial process operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0126] Aspect 41 provides a method for treating spent activated carbon comprising one or more sorbed PF AS compounds, the method comprising: introducing the spent activated carbon into a high-temperature industrial process operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed PFAS compounds.

[0127] Aspect 42 provides the method of Aspect 41, wherein the high-temperature industrial process operates at or above a temperature that is in the range of about 500 °F (260 °C) to about 6,000 °F (3,316 °C).4820.035W01

[0128] Aspect 43 provides the method of any one of Aspects 41-42, wherein the high- temperature industrial process operates at or above a temperature that is in the range of about 250 °F (121 °C) to about 2000 °F (1,093 °C).

[0129] Aspect 44 provides the method of any one of Aspects 41-43, wherein the high- temperature industrial process operates at or above a temperature that is in the range of about 500 °F (260 °C) to about 1200 °F (649 °C).

[0130] Aspect 45 provides the method of any one of Aspects 41-44, wherein the high- temperature industrial process operates at or above a temperature that is in the range of about 250 °F (121 °C) to about 1200 °F (649 °C).

[0131] Aspect 46 provides a method for steel production comprising: using spent activated carbon comprising one or more sorbed materials in steelmaking as charge carbon and / or injection carbon sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0132] Aspect 47 provides the method of Aspect 46, wherein activated carbon used to form the spent activated carbon is derived from biomass, wherein the method reduces greenhouse gas emissions compared to using a non-biomass-derived carbon source in place of the spent activated carbon.

[0133] Aspect 48 provides a method for producing coke comprising: heating spent activated carbon in the absence of oxygen, the spent activated carbon comprising one or more sorbed materials, to produce coke, wherein the heating is sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

[0134] Aspect 49 provides the method of Aspect 48, wherein the coke has a carbon content greater than 70 wt%.

[0135] Aspect 50 provides the method of any one of Aspects 48-49, wherein the coke has a carbon content greater than 80 wt%.

[0136] Aspect 51 provides the method of any one of Aspects 48-50, wherein the coke has a carbon content greater than 90 wt%.

[0137] Aspect 52 provides the method of any one of Aspects 48-51, wherein the spent activated carbon is derived from biomass-based activated carbon.

[0138] Aspect 53 provides the method of Aspect 52, wherein the biomass comprises agricultural waste, wood products, plant fibers, shell materials, cellulose, polymers, pitch, peat, or a combination thereof.4820.035W01

[0139] Aspect 54 provides the method of any one of Aspects 52-53, wherein the biomass comprises bamboo, coconut husk, willow peat, a wood product, coir, or a combination thereof.

[0140] Aspect 55 provides a method for producing graphite comprising: converting spent activated carbon comprising one or more sorbed materials to coke sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials; and processing the coke to produce graphite with 1 wt% to 99 wt% purity.

[0141] Aspect 56 provides a system for repurposing spent activated carbon comprising: a receiving facility for spent activated carbon comprising one or more sorbed materials; and processing, transport, storage, or handling equipment for introducing the spent activated carbon into a high-temperature industrial process.

[0142] Aspect 57 provides the system of Aspect 56, wherein the industrial process is selected from steelmaking, coke production, and graphite manufacturing.

[0143] Aspect 58 provides the system of any one of Aspects 56-57, further comprising: equipment for introducing added material to the spent activated carbon prior to introduction to the industrial process.

[0144] Aspect 59 provides the method or system of any one or any combination of Aspects 1-58 optionally configured such that all elements or options recited are available to use or select from.

Claims

4820.035W01CLAIMSWhat is claimed is:

1. A method for repurposing spent activated carbon comprising: introducing the spent activated carbon comprising one or more sorbed materials into a high-temperature industrial process to repurpose carbon content in the spent activated carbon.

2. The method of claim 1, wherein the spent activated carbon is powdered activated carbon, granulated activated carbon, an activated carbon filter, or a combination thereof.

3. The method of claim 1, wherein the use of the spent activated carbon in the high- temperature industrial process is sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

4. The method of claim 1, wherein the use of the spent activated carbon in the high- temperature industrial process is sufficient to destroy 90 wt% to 100 wt% of the one or more sorbed materials.

5. The method of claim 1, wherein the one or more sorbed materials comprise one or more chosen from a taste-affecting compound, an odor-affecting compound, a color-affecting compound, a hydrocarbon, an organic material, atrazine, glyphosate, trichloroethylene, tetrachloroethylene, a chlorinated hydrocarbon, a heavy metal, mercury, lead, arsenic, a nitrate, a nitrite, a solvent, a disinfection byproduct, chloroform, an endocrine-disrupting compound, a pharmaceutical compound, a pharmaceutical manufacturing byproduct, a personal-care product compound, a pesticides, a per- or poly-fluoroalkyl substance (PF AS), a polychlorinated biphenyl (PCB), a dioxin, a radioactive material, a fuel oil, and an industrial chemical.

6. The method of claim 1, wherein the one or more sorbed materials comprises a per- or poly-fluoroalkyl substance (PF AS), wherein the PFAS is a perfluoroalkyl substance, a polyfluoroalkyl substance, or a perfluoroalkyl acid (PFAA).

7. The method of claim 1, wherein the high-temperature industrial process comprises steelmaking.4820.035W018. The method of claim 7, wherein the spent activated carbon is used as charge carbon in the steelmaking process.

9. The method of claim 7, wherein the spent activated carbon is used as injection carbon in the steelmaking process.

10. The method of claim 7, wherein the steelmaking process operates at or above a temperature in the range of about 500 °F (260 °C) to about 3,000 °F (1,649 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

11. The method of claim 1, wherein the high-temperature industrial process comprises coke production to form produced coke.

12. The method of claim 11, comprising heating the spent activated carbon to a temperature of about 1,500 °F (816 °C) to about 3,000 °F (1,649 °C).

13. The method of claim 11, further comprising processing the coke to produce graphite with 1 wt% to 99 wt% purity.

14. The method of claim 1, wherein the high-temperature industrial process comprises graphite production.

15. The method of claim 14, comprising heating the spent activated carbon to approximately 4,000 °F (2,204 °C) to 6,000 °F (3,315 °C) in a controlled atmosphere.

16. The method of claim 1, further comprising adding one or more materials to the spent activated carbon prior to or during the introducing of the spent activated carbon into the industrial process, wherein the one or more added materials enhance performance of the spent activated carbon in the industrial process.

17. The method of claim 16, wherein the one or more added materials comprise one or more chosen from organics, metals, alkali materials, alkaline materials, clay-based materials, acids, salts, copper, chrome, manganese, magnesium, lime, limestone, trona, halides, halide4820.035W01 salts, bentonite, kaolinite, montmorillonite, smectite, illite, chlorite, vermiculite, talc, pyrophyllite, a sugar, a fat, a protein, a carbohydrate, DNA, cellulose, chlorophyll, an enzyme, a hormone, a vitamin, petroleum, natural gas, a food item, a binder, a sulfonate, a starch, and a coal tar pitch.

18. The method of claim 1, wherein activated carbon used to form the spent activated carbon is derived from biomass.

19. A method for treating spent activated carbon comprising one or more sorbed materials, the method comprising: introducing the spent activated carbon into a high-temperature industrial process operating at or above a temperature in the range of about 250 °F (121 °C) to about 6,000 °F (3,316 °C) sufficient to destroy 50 wt% to 100 wt% of the one or more sorbed materials.

20. A system for repurposing spent activated carbon comprising: a receiving facility for spent activated carbon comprising one or more sorbed materials; and processing, transport, storage, or handling equipment for introducing the spent activated carbon into a high-temperature industrial process.

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