In-SITU bayer process aluminum-water reaction

Abstract

Provided herein are methods and systems for producing alumina trihydrate (Al(OH)3) and / or alumina (Al2O3). The methods and systems utilize energy extracted from the aluminum-water reaction to power the conversion of various aluminum sources to alumina trihydrate.

Description

IN-SITU BAYER PROCESS ALUMINUM- WATER REACTIONCROSS-REFERENCE TO RELATED APPLICATIONS

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 665,611, filed on June 28, 2024, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.BACKGROUND

[0002] Aluminum hydroxide (A1(OH)3), also known as alumina trihydrate, is a widely used chemical around the world in industries ranging from aluminum (e.g., as a precursor to alumina (AI2O3)) to pharmaceuticals (e.g., as a compound in antacid and other medications) to industrial polymers (e.g., as a fire suppressing additive). Presently, the majority of the world’s Al(0H)3 supply is produced via the Bayer Process, which involves dissolving aluminum-containing oxide and hydroxide species (e.g., A1(OH)3, AI2O3, A100H in their various phases) from bauxite ore in sodium hydroxide (NaOH) at elevated temperatures and pressures to produce dissolved sodium aluminate (Na[Al(OH)4]). A1(OH)3 is then precipitated out either using seed crystals in a supersaturated solution or using CO2 to also produce sodium carbonate (NazCOs). In the former case, the sodium hydroxide is mostly recovered and reused to continue the process. The remaining impurities in the Bauxite ore are discarded as an environmentally hazardous waste stream called “red mud.”

[0003] The Bayer process is considered to be a non-environmentally benign process, as there are greenhouse gas emissions associated with energy required for mining and transportation of the Bauxite, as well as the heat and steam energy required to run the Bayer process, which is typically generated via the combustion of fossil fuels. Additionally, the waste tailings of the Bayer Process when using Bauxite as feedstock is a caustic mixture of primarily iron oxides and NaOH that must be stored in large environmentally harmful open-air lagoons.SUMMARY

[0004] New and improved processes, systems, and devices that mitigate the environmental impact of the Bayer process are provided herein.

[0005] Provided herein are methods, systems, and devices for producing alumina trihydrate (Al(0H)3) and / or alumina (AI2O3). In some embodiments a method of producing alumina trihydrate (A1(OH)3) comprises:combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A100H), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([Al(0H)4]"), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0006] In some embodiments, a method of producing alumina trihydrate (Al(OH)s) comprises: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate (A1(OH)3) and / or aluminum oxyhydroxide (A1OOH), wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4] ), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0007] In some embodiments, a method of producing alumina (AI2O3) comprises: combining activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH), wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4] ), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; precipitating alumina trihydrate from the liquor; and heating the alumina trihydrate thereby producing alumina.

[0008] In some embodiments, a method of producing alumina trihydrate (A1(OH)3) comprises: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4]'); andprecipitating alumina trihydrate (Al(OH)s) from the liquor.

[0009] In some embodiments, a method of producing alumina trihydrate (Al(OH)s) comprises: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4]"); and precipitating alumina trihydrate (A1(OH)3) from the liquor.

[0010] In some embodiments, a method of producing alumina (AI2O3) comprises: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4]"); precipitating alumina trihydrate (A1(OH)3) from the liquor; and heating the alumina trihydrate thereby producing alumina.[Oil] In some embodiments, the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide. In certain embodiments, the hydroxide base is sodium hydroxide.

[0012] In some embodiments, the non-activated aluminum source is added to the reaction chamber in one portion. In some embodiments, the non-activated aluminum source is added to the reaction chamber in multiple portions. In some embodiments, the non-activated aluminum source is added to the reaction chamber at least every 30 seconds. In some embodiments, the non-activated aluminum source is added to the reaction chamber continuously. In some embodiments, the hydroxide base and water are added to the reaction chamber prior to addition of the activated aluminum.

[0013] In some embodiments, the method further comprises stirring the mixture in the reaction chamber. In some embodiments, the method further comprises stirring the activated aluminum comprising aluminum and a catalyst composition, the water, and the hydroxide base in the reaction chamber.

[0014] In some embodiments, the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, aluminum oxide (AI2O3), and metallic aluminum. In some embodiments, the metallic aluminum is substantially pure (e.g., >99% pure, >98% pure, >97% pure, >96% pure, or >95% pure). In some embodiments, the metallic aluminum contains impurities.

[0015] In some embodiments, the catalyst composition is a low-melting liquid metal alloy. In some embodiments, the catalyst composition comprises gallium and / or indium. In some embodiments, the catalyst composition is a non-eutectic alloy comprising bismuth, tin, indium, and gallium. In some embodiments, the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium. In some embodiments, the catalyst composition comprises gallium and indium. In some embodiments, the catalyst composition comprises gallium, indium, and tin.

[0016] In some embodiments, steam is released in the reaction chamber.

[0017] In some embodiments, the method further comprises recovering the catalyst composition. In some embodiments, at least 95% of the catalyst composition is recoverable.

[0018] In some embodiments, the ratio of activated aluminum to non-activated aluminum in the reaction chamber is 100%. In some embodiments, the ratio of activated aluminum to nonactivated aluminum in the reaction chamber is at least 5%.

[0019] In some embodiments, the method further comprises maintaining the pH in the reaction chamber at pH 12-14. In some embodiments, the method further comprises maintaining the pH in the reaction chamber at pH 11-15. In some embodiments, the hydroxide is at its saturation point in the mixture. In some embodiments, maintaining the pH of the reaction mixture comprises sequential addition of hydroxide base to the reaction mixture. In some embodiments, the method further comprises controlling the pH in order to influence the relative concentrations of aluminum oxyhydroxide and alumina trihydrate produced by the reaction of the activated aluminum with water.

[0020] In some embodiments, the method further comprises maintaining the temperature in the reaction chamber at about 100 °C to about 200 °C.

[0021] In some embodiments, the method further comprises maintaining the pressure in the reaction chamber at about 1 bar to about 35 bar.

[0022] In some embodiments, heat released by the reaction of the activated aluminum and water increases and / or maintains the temperature and / or pressure in the reaction chamber. In some embodiments, heat is released by reaction of the activated aluminum and water, and the heat increases and / or maintains the temperature and / or pressure in the reaction chamber. In some embodiments, the conversion of the non-activated aluminum source to aluminate proceeds without an external heat input. In some embodiments, the non-activated aluminum source is converted to aluminate without an external heat input. In some embodiments, addition of the activated aluminum reduces the required external heat input for conversion of the non-activatedaluminum source to the aluminate. In some embodiments, the non-activated aluminum source is converted to aluminate, and addition of the activated aluminum reduces the required external heat input for conversion of the non-activated aluminum source to the aluminate.

[0023] In some embodiments, the alumina trihydrate is precipitated from the liquor in the reaction chamber. In some embodiments, the alumina trihydrate is precipitated from the aluminate liquor in a separate crystallization chamber. In some embodiments, the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

[0024] In some embodiments, precipitating the alumina trihydrate comprises adding a seed crystal to the reaction chamber or crystallization chamber. In some embodiments, precipitating the alumina trihydrate comprises bubbling carbon dioxide gas through the aluminate liquor and further produces carbonate (e.g., sodium carbonate).

[0025] In some embodiments, the method further comprises filtering impurities from the liquor prior to precipitation of aluminate.

[0026] In some embodiments, A1(OH)3 produced by reaction of the activated aluminum with water is precipitated from the liquor.

[0027] In some embodiments, the method further comprises heating the alumina trihydrate to a temperature of 1400 K to 1500 K, thereby producing alumina.

[0028] In some embodiments, the hydrogen gas and / or steam is used to power a separate process. In some embodiments, the hydrogen is used to generate electricity via a fuel cell. In some embodiments, the steam is used to power a turbine.

[0029] In some embodiments, a system for producing alumina trihydrate (A1(OH)3) comprises: a device for producing alumina trihydrate (A1(OH)3) comprising a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, andwherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

[0030] In some embodiments, the first product outlet is configured to release a liquor comprising aluminate ([Al(0H)4]'). In some embodiments, the first product outlet is configured to release alumina trihydrate.

[0031] In some embodiments, the system further comprises a crystallization chamber comprising a first product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide outlet.

[0032] In some embodiments, the second product outlet is configured to release alumina trihydrate.

[0033] In some embodiments, the system further comprises a heat source for calcining the alumina trihydrate to produce alumina, comprising an interior volume and exterior wall, wherein the exterior wall comprises a second product inlet in fluid communication with the first product outlet of the device or the second product outlet of the crystallization chamber. In some embodiments, the heat source is a kiln.

[0034] In some embodiments, a system for producing alumina trihydrate (Al(OH)s) comprises a reaction chamber and instructions therefor configured to produce alumina trihydrate (A1(OH)3) by: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in the reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4] ), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0035] In some embodiments, the system further comprises a heat source and is configured to produce alumina (AI2O3) by heating the alumina trihydrate with the heat source, thereby producing alumina.

[0036] In some embodiments, the system precipitates the alumina trihydrate in the reaction chamber. In some embodiments, the system further comprises a crystallization chamber separate from the reaction chamber configured to precipitate the alumina trihydrate therein.

[0037] In some embodiments, a system for producing alumina trihydrate (A1(OH)3) and / or alumina (AI2O3) comprises: a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet extending therethrough, a first water inlet extending therethrough, a hydroxide base inlet extending therethrough, a gravity-fed catalyst composition outlet extending therethrough, a steam outlet extending therethrough, a hydrogen outlet extending therethrough and a first product outlet extending therethrough, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, wherein at least activated aluminum comprising aluminum and a catalyst composition, water, and hydroxide base are disposed within the interior volume, and wherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

[0038] In some embodiments, the system further comprises a non-activated aluminum source or non-activated aluminum.

[0039] In some embodiments, the first product outlet is configured to release a liquor comprising aluminate ([A1(OH)4]"). In some embodiments, the first product outlet is configured to release alumina trihydrate.

[0040] In some embodiments, the system further comprises an alumina trihydrate crystallization chamber comprising a product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide base outlet, wherein a liquor comprising aluminate ([A1(OH)4] ) is disposed within the interior volume of the crystallization chamber.

[0041] In some embodiments, the second product outlet is configured to release alumina trihydrate.

[0042] In some embodiments, the system further comprises a heat source, wherein the heat source is a kiln or another source of heat.

[0043] In some embodiments, the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide. In some embodiments, the hydroxide base is sodium hydroxide.

[0044] In some embodiments, the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, alumina (AI2O3), and metallic aluminum. In some embodiments, the metallic aluminum is substantially pure (e.g., >99% pure,>98% pure, >97% pure, >96% pure, or >95% pure). In some embodiments, the metallic aluminum contains impurities.

[0045] In some embodiments, the catalyst composition comprises is a low-melting liquid metal alloy. In some embodiments, the catalyst composition comprises gallium and / or indium. In some embodiments, the catalyst composition is a non-eutectic alloy comprising bismuth, tin, indium, and gallium. In some embodiments, the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium. In some embodiments, the catalyst composition comprises gallium and indium. In some embodiments, the catalyst composition comprises gallium, indium, and tin.

[0046] In some embodiments, steam is released from the reaction chamber. In some embodiments, the catalyst composition is directed through the catalyst outlet of the reaction chamber after the activated aluminum reacts with water.

[0047] In some embodiments, the ratio of activated aluminum to non-activated aluminum in the reaction chamber is 100%. In some embodiments, the ratio of activated aluminum to nonactivated aluminum in the reaction chamber is at least 5%.

[0048] In some embodiments, the hydroxide base is aqueous. In some embodiments, the pH in the reaction chamber is 12-14. In some embodiments, the pH in the reaction chamber is 11 - 15. In some embodiments, the hydroxide is at its saturation point in the mixture.

[0049] In some embodiments, the temperature in the reaction chamber is about 100 °C to about 200 °C. In some embodiments, the pressure in the reaction chamber is about 1 bar to about 35 bar.

[0050] In some embodiments, the reaction chamber does not require an external energy source for heating.

[0051] In some embodiments, the device produces alumina trihydrate in the reaction chamber. In some embodiments, the device produces alumina trihydrate in a separate crystallization chamber.

[0052] In some embodiments, the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

[0053] In some embodiments, an alumina trihydrate seed crystal is disposed in the interior volume of the crystallization chamber. In some embodiments, carbon dioxide gas is bubbled through the contents of the reaction chamber and / or crystallization chamber.

[0054] In some embodiments, the system further comprises a filter for removing impurities.

[0055] In some embodiments, the hydrogen gas and / or steam generated by the device is used to power a separate process. In some embodiments, the hydrogen is used to generate electricity via a fuel cell. In some embodiments, the steam is used to power a turbine.

[0056] In some embodiments, a method of calcining alumina trihydrate (Al(OH)s) and / or aluminum oxyhydroxide (A1OOH) to produce alumina (AI2O3) comprises heating the alumina trihydrate and / or aluminum oxyhydroxide in a kiln, wherein the kiln is partially or fully heated by the combustion of hydrogen produced by a method, system, or device disclosed herein.

[0057] In some embodiments, steam is removed from the hydrogen prior to combustion. In some embodiments, steam is removed by condensation or membrane separation.BRIEF DESCRIPTION OF THE DRAWINGS

[0058] FIG. 1 is a schematic drawing showing an embodiment of a system 1000 for producing alumina trihydrate including a reaction chamber 100, a stirring device 200, and a catalyst outlet 300.

[0059] FIG. 2 is a schematic drawing showing an embodiment of a system 2000 for producing alumina trihydrate including a reaction chamber 100, a stirring device 200, a catalyst outlet 300, and a crystallization chamber 400.

[0060] FIG. 3 is a schematic drawing showing an embodiment of a system 3000 for producing alumina trihydrate including a reaction chamber 100, a stirring device 200, and a catalyst outlet 300, with carbon dioxide bubbled through the reaction chamber.

[0061] FIG. 4. is a schematic drawing showing an embodiment of a system 4000 for producing alumina trihydrate including a reaction chamber 100, a stirring device 200, a catalyst outlet 300, and a crystallization chamber 400, with carbon dioxide bubbled through the crystallization chamber.

[0062] FIG. 5 is a schematic drawing showing an embodiment of a method for powering the calcination of alumina trihydrate aluminum using hydrogen gas produced in the aluminum water reaction, including separating the steam from the hydrogen by condensation 500 and combusting the hydrogen to heat a kiln 600

[0063] FIG. 6 is a schematic drawing showing an embodiment of a method for powering the calcination of alumina trihydrate aluminum using hydrogen gas produced in the aluminum water reaction, including separating the steam from the hydrogen by membrane separation 500 and combusting the hydrogen to heat a kiln 600.

[0064] FIG. 7 is an image of three 50 mL activated aluminum / aqueous NaOH reaction mixtures 30 minutes after reaction initiation. The image shows clear reaction mixtures having a gray color, with coalesced catalyst at the bottom of the mixtures.

[0065] FIG. 8 is an image of one of the reaction mixtures depicted in FIG. 7 one day after initiation of the reaction. The image shows a clear reaction mixture, with coalesced catalyst at the bottom of the mixture.

[0066] FIG. 9 is an image of a 250 mL activated aluminum / aqueous NaOH reaction mixture 30 minutes after reaction initiation. The image shows a slightly cloudy mixture.

[0067] FIG. 10 is an image of the reaction mixture depicted in FIG. 9 one hour after initiation of the reaction. The image shows a slightly cloudy mixture.

[0068] FIG. 11 is an image of the reaction mixture depicted in FIG. 9 one day after initiation of the reaction. The image shows an opaque mixture.DETAILED DESCRIPTION

[0069] As a way of mitigating the negative environmental effects of the Bayer Process industry, metallic aluminum can be used as an alternative to Bauxite ore both as a feedstock for the Bayer process, and also as a low-carbon energy carrier, particularly if metallic aluminum waste is used. In general, aluminum is a promising candidate for energy storage due to its high energy density, abundance, low cost, non-toxicity, non-volatility, and non-reactivity in storage. One method of extracting the energy from aluminum is to react it with water to form hydrogen and heat as described in Reactions 1 and 2.• Al + 2 H2O — > 1.5 H2 + A10(0H) + Qrcaction (Reaction 1)• Al + 3 H2O — > 1 .5 H2 + A1(OH)3 + Qreaction (Reaction 2)

[0070] Whether Reaction 1 or 2 is favored is a function of pH, temperature, and pressure. For example, at elevated temperatures, pressures, and pH, Reaction 2 is favored (Godart, P. https: / / dspace.mit.edu / handle / 172Ll / 139978; Godart, P. et al, https: / / www.sciencedirect.com / science / article / abs / pii / S0360319919311486). Conveniently for the Bayer Process, the final products of these aluminum-water reactions can serve as high-grade feedstocks for the Bayer Process at a much higher purity than when extracted from Bauxite ore. The energy released as a combination of the heating value of the hydrogen and the enthalpicheat released in the exothermic aluminum-water reaction (8.6 kWh / kg) can be used to provide thermal power to the Bayer Process and various other ancillary processes (e.g., electricity to run the plant) as well. If the aluminum used in this overall application is considered scrap aluminum or produced using low-carbon renewables, the use of this aluminum as a fuel has the potential to lower the carbon footprint of the original Bayer process, both from directly avoiding carbon emissions from the energy used in the process and the upstream mining emissions. Additionally, due to the high energy density of aluminum, this fuel can be a much more efficient and compact way of delivering energy to industrial sites that would otherwise not be easily connected to renewable energy sources.

[0071] To use aluminum as a fuel in this way, it must be able to be oxidized by water at a suitable reaction rate. Normally, aluminum will not react with water due to its highly passivating oxide layer. The oxide layer can be disrupted, however, by an appropriate catalyst, thereby “activating” the aluminum to make it water reactive. Some catalysts for this purpose include low-melting-point metal alloys that penetrate the grain boundary network of the aluminum, causing it to disintegrate and exposing non-oxidized internal surfaces to water.

[0072] The present disclosure provides methods and systems for producing alumina trihydrate and / or alumina that provide alternatives and / or improvements to the standard Bayer process. The methods and systems disclosed herein utilize, at least in part, metallic aluminum as a feedstock. At least a portion of the metallic aluminum comprises activated aluminum, which reacts upon contact with water to generate heat and hydrogen gas, each of which can be used to power the Bayer process (e.g., by generating the temperatures and pressures required for the Bayer process) and thereby produce alumina trihydrate; and to power other external processes (e.g., electricity generation in a hydrogen fuel cell, steam generation to rotate a turbine, etc.).

[0073] Terms used in the claims and specification are defined as set forth below unless otherwise specified.

[0074] It must be noted that, as used in the specification, the singular forms “a,” “an” and “the” include plural referents unless the context clearly dictates otherwise.

[0075] The phrase “and / or,” as used in the specification and in the claims, should be understood to mean “either or both” of the elements so conjoined, i.e., elements that are conjunctively present in some cases and disjunctively present in other cases. Multiple elements listed with “and / or” should be construed in the same fashion, i.e., “one or more” of the elements so conjoined. Other elements may optionally be present other than the elements specificallyidentified by the “and / or” clause, whether related or unrelated to those elements specifically identified. Thus, as a non-limiting example, a reference to “A and / or B”, when used in conjunction with open-ended language such as “comprising” can refer, in one embodiment, to A only (optionally including elements other than B); in another embodiment, to B only (optionally including elements other than A); in yet another embodiment, to both A and B (optionally including other elements).

[0076] As used in the specification and in the claims, “or” should be understood to have the same meaning as “and / or” as defined above. For example, when separating items in a list, “or” or “and / or” shall be interpreted as being inclusive, i.e., the inclusion of at least one, but also including more than one, of a number or list of elements, and, optionally, additional unlisted items. Only terms clearly indicated to the contrary, such as “only one of’ or “exactly one of,” or, when used in the claims, “consisting of,” will refer to the inclusion of exactly one element of a number or list of elements. In general, the term “or” as used shall only be interpreted as indicating exclusive alternatives (i.e., “one or the other but not both”) when preceded by terms of exclusivity, such as “either,” “one of,” “only one of,” or “exactly one of.”

[0077] The term “about,” as used herein, means approximately, in the region of, roughly, or around. Unless otherwise stated for a numerical value noted, when the term “about” is used in conjunction with a numerical range, it modifies that range by extending the boundaries above and below the numerical values set forth. Unless otherwise stated for a numerical value noted, the term “about” is used herein to modify a numerical value above and below the stated value by a variance of 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, or 50%. For nonlimiting example, a range of “about 2 to about 20” can mean 1.98 to 22, or 1 to 30, or other ranges therebetween. Unless otherwise stated for a percentage range noted, when the term “about” is used in conjunction with a percentage range, it modifies that range by extending the boundaries above and below the percentages set forth. Unless otherwise stated for the percentage noted, the term “about” is used herein to modify a percentage above and below the stated percentage by 1%, 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, or 50% (as an absolute, which may be limited to 0% as a minimum), or by a percentage of the stated percentage i.e. 1% 2%, 3%, 4%, 5%, 6%, 7%, 8%, 9%, 10%, 15%, 20%, 25%, or 50% of the percentage. For nonlimiting example, a range of “about 2% to about 20%” can mean 1% to 21%, or 0% to 70%, or other ranges therebetween, or 1.98% to 22%, or 1% to 30% (as a percentage of the percentage range). For nonlimiting example, a percentage value of “about 30%” can mean 29% to 31%, or 0% to 80%, or other ranges therebetween, or 27% to 33%, or15% to 45% (as a percentage of the percentage value), or other ranges therebetween. Unless otherwise stated for a numerical range noted, numerical ranges recited herein by endpoints include all numbers and fractions subsumed within that range (e.g., 1 to 5 includes 1, 1.5, 2, 2.75, 3, 3.90, 4, and 5). It is also to be understood that all numbers and fractions thereof are presumed to be modified by the term “about.”

[0078] As used herein, the term “combustion” refers to the exothermic reaction of a substance (e.g., hydrogen) with oxygen.

[0079] As used herein, the term “generator” refers to a machine that converts rotational motion (or rotational energy) into electrical current and / or voltage (or electrical energy).

[0080] As used herein, the term “work” refers to the interaction between two systems resulting in a transfer of energy from one system or material (e.g., aluminum metal) to the other system (e.g., a turbine) or its surroundings.

[0081] As used herein, the phrase “aluminum-water reaction” refers to the oxidation reaction represented by either / both of the below chemical reactions:Al + 2 H2O — > 1.5 H2 + AIO(OH) + Qreaction (Reaction 1)Al + 3 H2O 1.5 H2 + Al(0H)3 + Qreaction (Reaction 2) wherein Qreaction represents the heat released as a product of the reaction. Whether the reaction of Reaction 1 or the reaction of Reaction 2 occurs depends on the environmental conditions of the reaction, such as, pressure, temperature, and pH.

[0082] As used herein, the term “water” refers to H2O in a liquid state. As used herein, the term “steam” refers to H2O in a gaseous state.

[0083] As used herein, the term “eutectic” refers to a mixture of substances that freezes at a temperature that is lower than the freezing points of the separate constituents. In certain embodiments, the term “eutectic” is used to describe a mixture of indium and gallium.

[0084] The term “subset,” as used herein, refers to a group of all or less than all of the elements of a set (e.g., a subset of devices). The term may be used to encompass a group from 1 % of all elements up to all elements (100%).

[0085] The term “substantially,” as used herein, is a broad term, and is to be given its ordinary and customary meaning to a person of ordinary skill in the art (and is not to be limitedto a special or customized meaning), and refers without limitation to being largely but not necessarily wholly that which is specified. For example, the term “to substantially separate,” as used herein refers to the removal, whether completely or partially (e.g., removal of 1% or more, 5% or more, 10% or more, 20% or more, 30% or more, 40% or more, 50% or more, 60% or more, 70% or more, 80% or more, 90% or more, 95% or more, 96% or more, 97% or more, 98% or more, 99% or more, or 99.9%), of an unwanted constituent from a mixture containing two or more constituents mixed together.

[0086] The term “room temperature” as used herein refers to 20 °C.Activated Aluminum

[0087] The methods and devices described herein utilize activated aluminum comprising aluminum and a catalyst composition, wherein the activated aluminum is capable of reacting with water (e.g., via the aluminum water reaction) to produce heat and hydrogen gas. Methods of manufacturing activated aluminum that may be used in the methods provided herein are known in the art and generally involve surface treatment of aluminum (e.g., bulk aluminum) with an activating metal alloy in liquid form (i.e., above its melting temperature) in sufficient quantity to substantially coat the surface of the aluminum, for an amount of time sufficient to allow the activating metal alloy to diffuse through the microstructure of the aluminum, thereby activating the aluminum for reaction with water. Non- limiting examples of methods for activating aluminum are described by Godart (Peter Godart. “Mechanisms of Liquid-Metal- Activated Aluminum- Water Reactions and Their Application.” PhD thesis. Massachusetts Institute of Technology, 2021. URL: https: / / dspace.mit.edu / handle / 172Ll / 139978), the entire contents of which are incorporated herein by reference. Methods for recycling aluminum scrap metal for use in the methods provided herein are described in US Patent Application Publication No. US 2022 / 0074023, the entire contents of which are incorporated herein by reference.

[0088] In some embodiments, the catalyst composition is capable of penetrating the grain boundary network of aluminum to form activated aluminum. Penetration of the grain boundary network by the catalyst composition causes the activated aluminum to disintegrate upon contact with water, thereby exposing non-oxidized, water-reactive internal surfaces to water.

[0089] In some embodiments, the catalyst composition is present in the activated aluminum in an amount of about 2% to about 20%, about 2% to about 18%, about 2% to about 16%, about 2% to about 14%, about 2% to about 12%, about 2% to about 10%, about 2% to about 8%, or about 2% to about 4% by weight. In some embodiments, the catalyst composition is present inthe activated aluminum in an amount of about 1 %, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, about 10%, about 11%, about 12%, about 13%, about 14%, about 15%, about 16%, about 17%, about 18%, about 19%, or about 20% by weight.

[0090] In some embodiments, the activated aluminum has a catalyst composition-aluminum mass ratio of from about 1% to about 10%.

[0091] In some embodiments, the activated aluminum includes a plurality of aluminum pieces of varying size and shape. In some embodiments, the activated aluminum includes activated aluminum pieces of a first size and at least a second size. In some embodiments, the activated aluminum includes aluminum pieces of a first shape and at least a second shape.

[0092] In some embodiments of the methods described herein, the aluminum or alloy thereof is not in powder form. In some embodiments of the methods described herein, the aluminum or alloy thereof is in the form of pellets. In some embodiments, the pellets have a diameter of about 5 mm, about 6 mm, about 7 mm, about 8 mm, about 9 mm, about 10 mm, about 15 mm, about 20 mm, about 30 mm, about 40 mm, about 50 mm, about 60 mm, about 70 mm, about 80 mm, about 90 mm, or about 100 mm. In some embodiments, the pellets have a diameter of about 5 mm to about 20 mm. In some embodiments, the pellets have a diameter of about 70 mm.

[0093] In some embodiments, the activated aluminum in the reaction chamber is activated by the catalyst composition with a catalyst composition-aluminum mass ratio of from about 1% to about 10% (e.g., about 1%, about 2%, about 3%, about 4%, about 5%, about 6%, about 7%, about 8%, about 9%, or about 10 %).

[0094] In some embodiments, the activated aluminum has a purity of about 80% to about 100%, about 82% to about 100%, about 84% to about 100%, about 86% to about 100%, about 88% to about 100 %, about 90% to about 100%, about 92% to about 100%, about 94% to about 100%, about 96% to about 100%, about 98% to about 100%, about 80% to about 98%, about 80% to about 96%, about 80% to about 94%, about 80% to about 92%, about 80% to about 90%, about 80% to about 88%, about 80% to about 86%, about 80% to about 84%, about 80% to about 82%. In some embodiments, the activated aluminum has a purity of about 80%, about 82%, about 84%, about 86%, about 88%, about 90%, about 92%, about 94%, about 96%, about 98%, or about 100%. In some embodiments, the activated aluminum is recycled from scrap aluminum. In some embodiments, the activated aluminum has been fabricated from aluminum chips. In some embodiments, the activated aluminum chips are compacted to produce aluminum pellets.

[0095] In certain embodiments, the catalyst composition is a low-melting liquid metal alloy (e.g., comprising gallium and / or indium). In certain embodiments, the catalyst composition comprises gallium and / or indium.

[0096] In some embodiments, the catalyst composition is at least about 6% or about 6% of the total mass of the water-reactive aluminum composition.

[0097] In some embodiments, the catalyst composition comprises one or more alloying elements selected from the group consisting of copper, silicon, iron, manganese, zinc, titanium, magnesium, lithium, cadmium, zirconium, beryllium, scandium, sodium, cerium, yttrium, silver, calcium, boron, chromium, bismuth, lead, vanadium, nickel, cobalt, oxygen, or gallium, the alloying elements having in total from 0 to about 20% of the total mass of the aluminum.

[0098] In some embodiments, the catalyst composition is a non-eutectic alloy comprising bismuth, tin, indium, and gallium.

[0099] In some embodiments, the activating metal alloy comprises gallium and indium. In some embodiments, the activating metal alloy comprises gallium, indium, and tin.

[0100] In certain embodiments, the catalyst composition comprises Field’s Metal, comprising about 51% (e.g., about 51.2%) indium; about 32% (e.g., about 32.0%) bismuth; and about 17% (e.g., about 16.8%) tin by mass.

[0101] In some embodiments, the catalyst composition comprises less than about 10% gallium by mass.

[0102] In some embodiments, the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium.

[0103] In some embodiments, the catalyst composition may comprise from about 5 % to about 10 % gallium by mass, from about 1 % to about 5 % gallium by mass, from 0 % to about 1 % gallium by mass, or 0 % gallium by mass.

[0104] In some embodiments, the catalyst composition may comprise from about 46 % to about 48 % indium by mass, from about 48 % to about 50 % indium by mass, from about 50 % to about 51 % indium by mass, or from about 51 % to about 53 % indium by mass.

[0105] In some embodiments, the catalyst composition may comprise from about 28 % to about 30 % bismuth by mass, from about 30 % to about 31 % bismuth by mass, from about 31 % to about 32 % bismuth by mass, or from about 32 % to about 34 % bismuth by mass.

[0106] In some embodiments, the catalyst composition may comprise from about 15 % to about 16 % tin by mass, 16 %-l 6.5 % tin by mass, 16.5 %- 16.8 % tin by mass, or 16.85-18 % tin by mass.

[0107] In one embodiment, the catalyst composition may comprise about 6 % gallium, about 48 % indium, about 30 % bismuth, and about 16 % tin.

[0108] In other embodiments, the catalyst composition is solid at room temperature (e.g., at 20 °C).

[0109] In certain embodiments, the catalyst composition is liquid below the melting point of indium (about 157 °C).Methods / Processes

[0110] The present disclosure provides, in part, methods / processes for refining metallic aluminum and other aluminum-containing compounds (including bauxite ore) to produce alumina trihydrate and / or alumina using energy extracted from an aluminum- water reaction system.

[0111] In some embodiments, provided herein is a method of producing alumina trihydrate (A1(OH)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4]"), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0112] In some embodiments, provided herein is a method of producing alumina trihydrate (A1(OH)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate (A1(OH)3) and / or aluminum oxyhydroxide (A1OOH), wherein the alumina trihydrate and / or aluminum oxyhydroxide in themixture are further converted to aqueous aluminate ([Al(0H)4]‘), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0113] In some embodiments, provided herein is a method of producing alumina (AI2O3), the method comprising: combining activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A100H), wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to dissolved aluminate ([A1(OH)4]‘), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; precipitating alumina trihydrate from the liquor; and heating the alumina trihydrate thereby producing alumina.

[0114] In some embodiments, provided herein is a method of producing alumina trihydrate (A1(OH)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4] ); and precipitating alumina trihydrate (Al / OHh) from the liquor.

[0115] In some embodiments, provided herein is a method of producing alumina trihydrate (A1(OH)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4] ); and precipitating alumina trihydrate (Al / OHh) from the liquor.

[0116] In some embodiments, provided herein is a method of producing alumina trihydrate (A1(OH)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([A1(OH)4]’); precipitating alumina trihydrate (Al / OHh) from the liquor; andheating the alumina trihydrate thereby producing alumina.

[0117] In some embodiments, the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide. In some embodiments, the hydroxide base is sodium hydroxide.

[0118] In some embodiments, the non-activated aluminum source is added to the reaction chamber in one portion. In some embodiments, the non-activated aluminum source is added to the reaction chamber in multiple portions. In some embodiments, the non-activated aluminum source is added to the reaction chamber every 30 seconds, 1 minute, 2 minutes, 3 minutes, 4 minutes, 5 minutes, 10 minutes, 20 minutes, 30 minutes, 40 minutes, 50 minutes, or 1 hour. In some embodiments, the non-activated aluminum source is added to the reaction chamber at least every 30 seconds. In some embodiments, the non-activated aluminum source is added to the reaction chamber continuously.

[0119] In some embodiments, the hydroxide base and water are added to the reaction chamber prior to addition of the activated aluminum.

[0120] In some embodiments, the method further comprises stirring the mixture in the reaction chamber.

[0121] In some embodiments, the method further comprises stirring the activated aluminum comprising aluminum and a catalyst composition, the water, and the hydroxide base in the reaction chamber.

[0122] In some embodiments, the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, alumina (AI2O3), and metallic aluminum. In certain embodiments, the non-activated aluminum source comprises metallic aluminum. In some embodiments, the metallic aluminum is substantially pure (e.g., >99% pure, >98% pure, >97% pure, >96% pure, or >95% pure). In some embodiments, the metallic aluminum contains impurities. In some embodiments, the impurities are selected from the group consisting of organics (e.g. plastic), various metal oxides (e.g. oxides of iron, magnesium, and / or zinc), and various metals (e.g. iron, magnesium, lithium, zinc, and / or copper). In some embodiments, the metallic aluminum is about 90% to about 95% pure, or about 95% to about 100% pure. In some embodiments, the metallic aluminum is scrap aluminum.

[0123] In some embodiments, steam is released in the reaction chamber.

[0124] In some embodiments, the method further comprises recovering the catalyst composition. In some embodiments, the catalyst composition is recoverable after reaction of the aluminum with water. In some embodiments, the catalyst composition is recoverable in an amount of about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%. In some embodiments, at least 95% of the catalyst composition is recoverable.

[0125] In some embodiments, the method comprises producing alumina trihydrate and / or alumina at a rate of 10 kg / hour, 20 kg / hour, 30 kg / hour, 40 kg / hour, 50 kg / hour, 100 kg / hour, 200 kg / hour, 300 kg / hour, 400 kg / hour, 500 kg / hour, 1 ton / hour, 10 tons / hour, 50 tons / hour, 100 tons / hour, 200 tons / hour, 300 tons / hour, 400 tons / hour, 500 tons / hour, or 1,000 tons / hour. In some embodiments, the method comprises producing alumina trihydrate and / or alumina at a rate of at least 10 kg / hour.

[0126] In some embodiments, the ratio of activated aluminum to non-activated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber is about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%. In some embodiments, the ratio of activated aluminum to nonactivated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber is 100%. In some embodiments, the ratio of activated aluminum to non-activated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber is less than 5%, less than 10%, less than 15%, or less than 20%. In some embodiments, the ratio of activated aluminum to non-activated aluminum source in the reaction chamber is at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 45%, or at least 50%.

[0127] In some embodiments, the conversion of the activated aluminum and / or the nonactivated aluminum source to aluminate proceeds to at least 50% completion, at least 60% completion, at least 70% completion, at least 80% completion, or at least 90% completion. In some embodiments, the conversion of the activated aluminum and / or the non-activated aluminum source to aluminate takes about 30 minutes, about 1 hour, about 1.5 hours, about 2 hours, about 2.5 hours, about 3 hours, about 3.5 hours, or about 4 hours to proceed to at least 90% completion.

[0128] In some embodiments, the method further comprises maintaining the pH in the reaction chamber at pH 11-15. In some embodiments, the method further comprises maintainingthe pH in the reaction chamber at pH 11 - 14. In some embodiments, the method further comprises maintaining the pH in the reaction chamber at pH 12-14. In some embodiments, the method further comprises maintaining the pH in the reaction chamber at pH 14 or below. In some embodiments, maintaining the pH of the reaction mixture comprises sequential addition of the hydroxide base to the reaction mixture. In some embodiments, the hydroxide is at its saturation point in the mixture. In some embodiments, the w / w ratio of hydroxide base to water in the reaction chamber is 1 :1.

[0129] In some embodiments, the method further comprises controlling the pH in order to influence the relative concentrations of aluminum oxyhydroxide and alumina trihydrate produced by the reaction of the activated aluminum with water. In some embodiments, the reaction mixture is maintained at pH less than 11 , thereby increasing the concentration of aluminum oxyhydroxide relative to alumina trihydrate. In some embodiments, the reaction mixture is maintained at pH 11-14, thereby increasing the concentration of alumina trihydrate relative to aluminum oxyhydroxide.

[0130] In some embodiments, the method further comprises maintaining the temperature in the reaction chamber at about 100 °C to about 200 °C.

[0131] In some embodiments, the method further comprises maintaining the pressure in the reaction chamber at about 1 bar to about 35 bar. In some embodiments, the method further comprises maintaining the pressure in the reaction chamber at about 1 bar to about 15 bar.

[0132] In some embodiments, the heat released by the reaction of the activated aluminum and water increases and / or maintains the temperature and / or pressure in the reaction chamber. In some embodiments, the conversion of the non-activated aluminum source to aluminate proceeds without an external heat input. In some embodiments, addition of the activated aluminum reduces the required external heat input for conversion of the non-activated aluminum source to the aluminate.

[0133] In some embodiments, heat is released by reaction of the activated aluminum and water, and the heat increases and / or maintains the temperature and / or pressure in the reaction chamber. In some embodiments, the non-activated aluminum source is converted to aluminate without an external heat input. In some embodiments, the non-activated aluminum source is converted to aluminate, and addition of the activated aluminum reduces the required external heat input for conversion of the non-activated aluminum source to the aluminate.

[0134] In some embodiments, the alumina trihydrate is precipitated from the liquor in the reaction chamber. In some embodiments, the alumina trihydrate is precipitated from the aluminate liquor in a separate crystallization chamber. In some embodiments, the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

[0135] In some embodiments, precipitating the alumina trihydrate comprises adding a seed crystal to the reaction chamber or crystallization chamber. In some embodiments, precipitating the alumina trihydrate comprises bubbling carbon dioxide gas through the aluminate liquor and further produces carbonate (e.g., sodium carbonate).

[0136] In some embodiments, the method further comprises filtering impurities from the liquor prior to precipitation of aluminate.

[0137] In some embodiments, alumina trihydrate produced by reaction of activated aluminum with water is precipitated from the liquor.

[0138] In some embodiments, the alumina trihydrate is heated to a temperature of 1400 K to 1500 K, thereby producing alumina.

[0139] In some embodiments, the hydrogen gas and / or steam is used to power a separate process. In certain embodiments, the hydrogen is used to generate electricity via a fuel cell. In certain embodiments, the steam is used to power a turbine, e.g., a turbine of a generator.

[0140] In a specific embodiment, aluminum is reacted with water in a reactor containing an aqueous solution of sodium hydroxide (NaOH) at elevated temperatures and pressures to produce a combination of A1OOH and A1(OH)3; and H2 gas, as well as release heat directly from the change in enthalpy between the reaction products and reactants. The release of heat results in some combination of increasing or maintaining the temperature and pressure of the reaction products, as well as producing steam. The thermal energy release helps maintain the temperature and pressure required to carry out the overall process.

[0141] In specific embodiments, additional aluminum-containing compounds, including for example A1(OH)3, A1OOH, AI2O3, Bauxite Ore, and metallic aluminum along with various impurities, are continuously fed into the reactor, alongside the activated aluminum. The activated aluminum inputs catalyze the reaction, increasing overall reaction rates. In some embodiments, the final reaction products in the reactor are sodium aluminate, as well as various non-aluminum impurities from the aluminum-containing compounds, including organics (e.g.plastic), various metal oxides (e.g. oxides of iron, magnesium, and / or zinc), various metals (e.g. iron, magnesium, lithium, zinc, and / or copper). After the aluminum-water reaction process, pure Al(OH)s is produced by various means, including crystallization via pure Al(0H)3 seed crystals, or precipitation of Al(0H)3 by introducing CO2 to form sodium carbonate. In some embodiments, the CO2 comes from fossil-fuel-buming processes elsewhere as a form of carbon capture and storage. In some embodiments, before the purification step, impurities from the input aluminum-containing compounds are filtered out. In some embodiments, the pH of the reaction environment is controlled in order to influence the relative concentrations of A100H and Al(0H)3 produced, depending on the desired phase of the output. In each of these embodiments, the precipitation and crystallization of the various final reaction products may be carried out in separate vessels from the main reactor vessel, giving the operator flexibility in setting different temperatures and pressures that are optimal for the given inputs and configurations.

[0142] In specific embodiments, the hydrogen and steam produced in the aluminum-water reaction exit the reactor. The steam can be used to supply heat to additional processes, and the hydrogen can be separated from the steam to some degree and combusted to supply the heat needed for calcining the aluminum hydroxide species into alumina. In some embodiments, some of the hydrogen produced in the aluminum-water reaction is used to generate electricity via a fuel cell. In some embodiments, the hydrogen and steam are used to power turbomachinery to generate mechanical work (e.g. via a combined-cycle gas turbine or single Brayton cycle turbine).

[0143] For embodiments where a low-melting-point liquid metal alloy is used as a catalyst to pre-treat the metallic aluminum in order to increase reaction kinetics, a separator can be used to recover the liquid metal alloy directly from the reaction chamber. Given that the liquid metal alloy catalyst will be substantially more dense than the bulk of the other reactants and products, a gravity-driven separation method may be used. A valve located at the bottom of the reactor may be used to periodically drain the liquid metal catalyst, where it is recovered, washed, and used to treat additional metallic aluminum feedstock.

[0144] In another aspect, the present disclosure provides a method of calcining alumina trihydrate to produce alumina, the method comprising heating the alumina trihydrate in a kiln. In some embodiments, the kiln is partially or fully heated by the combustion of hydrogen produced by a method or system disclosed herein.

[0145] In some embodiments, steam is released from the reaction chamber and mixes with the hydrogen gas to form a mixture, and the steam content of the mixture is reduced prior to combustion of the hydrogen. In some embodiments, the steam content of the mixture is reduced by condensation. In some embodiments, the steam content of the mixture is reduced by membrane separation. In some embodiments, the ratio of hydrogen to steam in the mixture is about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90%. In some embodiments, ratio of hydrogen to steam in the mixture is about 15% or about 20%.

[0146] The present disclosure also provides, in part, systems for refining metallic aluminum and other various aluminum-containing compounds (including bauxite ore) to produce alumina trihydrate using energy extracted from an aluminum-water reaction system.

[0147] Provided herein are systems useful for producing alumina trihydrate (Al(0H)3) and / or alumina (AI2O3). In some embodiments, the system is useful producing alumina trihydrate. In some embodiments, the system comprises a device for producing alumina trihydrate. In some embodiments, the device for producing alumina trihydrate comprises a reaction chamber, thermal insulation, one or more sensors, and one or more impellers / agitators. In some embodiments, the reaction chamber comprises an interior volume and exterior wall. In some embodiments, the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet. In some embodiments, the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet. In some embodiments, one or more inputs / outputs may enter / exit the reaction chamber via the same inlet / outlet (e.g., the steam outlet and the hydrogen outlet may be one and the same). In some embodiments, the system further comprises a crystallization chamber. In some embodiments, the crystallization chamber comprises a first product inlet in fluid communication with the first product outlet of the reactionchamber, a second water inlet, a second product outlet, and an aqueous hydroxide outlet. In some embodiments, the system further comprises a steam separator capable of reducing the steam content of a mixture of hydrogen and steam produced by the device.

[0148] In some embodiments, the system is useful for producing alumina. In some embodiments, the system comprises a device for producing alumina trihydrate and a heat source for calcining the alumina trihydrate to produce alumina. In some embodiments, the device for producing alumina trihydrate comprises a reaction chamber, thermal insulation, one or more sensors, and one or more impellers / agitators. In some embodiments, the reaction chamber comprises an interior volume and exterior wall. In some embodiments, the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet. In some embodiments, the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet. In some embodiments, one or more inputs / outputs may enter / exit the reaction chamber via the same inlet / outlet (e.g., the steam outlet and the hydrogen outlet may be one and the same). In some embodiments, the system further comprises a crystallization chamber. In some embodiments, the crystallization chamber comprises a first product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide outlet. In some embodiments, the heat source comprises an interior volume and exterior wall, wherein the exterior wall comprises a second product inlet in fluid communication with the first product outlet of the device or the second product outlet of the crystallization chamber. In some embodiments, the heat source is a kiln. In some embodiments, the system further comprises a steam separator configured to reduce the steam content of a mixture of hydrogen and steam produced by the device.

[0149] In some embodiments, at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base are disposed within the interior volume of the reaction chamber.

[0150] In some embodiments, the system is configured to produce alumina trihydrate by combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber to form a mixture, and producing an aluminate liquor from the mixture; and precipitating alumina trihydrate from the liquor. In some embodiments, the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH). In some embodiments, the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4]'), thereby producing the liquor from the mixture.

[0151] In some embodiments, the system is configured to produce alumina by combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber to form a mixture, and producing a liquor comprising aqueous aluminate from the mixture; precipitating alumina trihydrate from the liquor; and heating the alumina trihydrate thereby producing alumina. In some embodiments, the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH). In some embodiments, the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4]"), thereby producing the liquor from the mixture.

[0152] In some embodiments, the system precipitates the alumina trihydrate in the reaction chamber. In some embodiments, the system comprises a crystallization chamber separate from the reaction chamber configured to precipitate the alumina trihydrate therein.

[0153] In some embodiments, provided herein is a system for producing alumina trihydrate (A1(OH)3), the system comprising: a device for producing alumina trihydrate ( AKOl I h) comprising a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, andwherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

[0154] In some embodiments, the first product outlet is configured to release a liquor comprising aqueous aluminate. In some embodiments, the first product outlet is configured to release alumina trihydrate.

[0155] In some embodiments, the system further comprises a crystallization chamber comprising a first product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide outlet.

[0156] In some embodiments, the second product outlet is configured to release alumina trihydrate.

[0157] In some embodiments, the system further comprises a heat source for calcining the alumina trihydrate to produce alumina, comprising an interior volume and exterior wall, wherein the exterior wall comprises a second product inlet in fluid communication with the first product outlet of the device or the second product outlet of the crystallization chamber. In some embodiments, the heat source is a kiln.

[0158] In some embodiments, provided herein is a system for producing alumina trihydrate (A1(OH)3), the system comprising a reaction chamber and instructions therefor configured to produce alumina trihydrate (A1(OH)3) by: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in the reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A1OOH), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([A1(OH)4]'), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

[0159] In some embodiments, the system further comprises a heat source and is configured to produce alumina (AI2O3) by heating the alumina trihydrate with the heat source, thereby producing alumina.

[0160] In some embodiments, the system precipitates the alumina trihydrate in the reaction chamber. In some embodiments, the system comprises a crystallization chamber separate from the reaction chamber configured to precipitate the alumina trihydrate therein.T1

[0161] In some embodiments, provided herein is a system for producing alumina trihydrate (A1(OH)3), the system comprising a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet extending therethrough, a first water inlet extending therethrough, a hydroxide base inlet extending therethrough, a gravity-fed catalyst composition outlet extending therethrough, a steam outlet extending therethrough, a hydrogen outlet extending therethrough and a first product outlet extending therethrough, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, wherein at least activated aluminum comprising aluminum and a catalyst composition, water, and hydroxide base are disposed within the interior volume, and wherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

[0162] In some embodiments, the system further comprises a non-activated aluminum source or non-activated aluminum.

[0163] In some embodiments, the first product outlet is configured to release liquor comprising aqueous aluminate. In some embodiments, the first product outlet is configured to release alumina trihydrate.

[0164] In some embodiments, the system further comprises an alumina trihydrate crystallization chamber comprising a product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide base outlet, wherein a liquor comprising aluminate ([A1(OH)4]’) is disposed within the interior volume of the crystallization chamber.

[0165] In some embodiments, the second product outlet is configured to release alumina trihydrate.

[0166] In some embodiments, the system further comprises a heat source, wherein the heat source is a kiln or another source of heat.

[0167] In some embodiments, the system produces alumina trihydrate and / or alumina at a rate of 10 kg / hour, 20 kg / hour, 30 kg / hour, 40 kg / hour, 50 kg / hour, 100 kg / hour, 200 kg / hour, 300 kg / hour, 400 kg / hour, 500 kg / hour, 1 ton / hour, 10 tons / hour, 50 tons / hour, 100 tons / hour, 200 tons / hour, 300 tons / hour, 400 tons / hour, 500 tons / hour, or 1,000 tons / hour. In some embodiments, the system produces alumina trihydrate and / or alumina at a rate of at least 10 kg / hour.

[0168] In some embodiments, the system further comprises one or more pumps.

[0169] In some embodiments, the system further comprises a filter for removing impurities.In some embodiments, the impurities are selected from the group consisting of organics (e.g. plastic), various metal oxides (e.g. oxides of iron, magnesium, and / or zinc), and various metals (e.g. iron, magnesium, lithium, zinc, and / or copper).

[0170] In some embodiments, the hydrogen gas and / or steam generated by the system is used to power a separate process. In some embodiments, the hydrogen is used to generate electricity via a fuel cell. In some embodiments, the steam is used to power a turbine, e.g., the turbine of a generator. In some embodiments, the steam and / or hydrogen are used to heat a kiln, wherein the kiln contains alumina trihydrate and / or aluminum oxyhydroxide that is calcined to alumina upon heating.Reaction chamber

[0171] Provided herein are systems for producing alumina trihydrate and / or alumina that comprise a device comprising a reaction chamber. In some embodiments, the reaction chamber includes an interior volume and exterior wall. In some embodiments, the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet. In some embodiments, the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet. In some embodiments, the reaction chamber further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator. In some embodiments, the hydrogen and / or steam outlets are configured to direct hydrogen and / or steam from the reaction chamber toward an external system or device (e.g., a fuel cell, turbine, steam separator, combustion chamber or kiln). In some embodiments, the product outlet is configured to remove product (e.g., alumina trihydrate) from the system. In some embodiments, the product outlet is configured to direct product (e.g., aluminate liquor) to a crystallization chamber.

[0172] In some embodiments, the reaction chamber is configured for recovery of the catalyst composition. In some embodiments, the catalyst composition is recoverable in an amount of about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%. In some embodiments, at least 95% of the catalyst composition is recoverable. In some embodiments, the catalyst composition forms a separate phase within the reaction chamber and settles to the base of the reaction chamber via gravity.

[0173] In some embodiments, at least activated aluminum comprising aluminum and a catalyst composition, water, and hydroxide base are disposed within the interior volume of the reaction chamber. In some embodiments, at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and hydroxide base are disposed within the interior volume of the reaction chamber. In some embodiments, an aluminum trihydrate seed crystal is disposed within the interior volume of the reaction chamber.

[0174] In some embodiments, the impeller and / or agitator mixes the contents of the reaction chamber.

[0175] In some embodiments, the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide. In some embodiments, the hydroxide base is sodium hydroxide.

[0176] In some embodiments, the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, alumina (AI2O3), and metallic aluminum. In some embodiments, the metallic aluminum is substantially pure (e.g., >99% pure, >98% pure, >97% pure, >96% pure, or >95% pure). In some embodiments, the metallic aluminum contains impurities.

[0177] In some embodiments, the catalyst composition is a low-melting liquid metal alloy.

[0178] In some embodiments, the catalyst composition comprises gallium and / or indium.

[0179] In some embodiments, the catalyst composition is a non-eutectic alloy comprising bismuth, tin, indium, and gallium. In some embodiments, the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium.

[0180] In some embodiments, the catalyst composition comprises indium and gallium. In some embodiments, the catalyst composition comprises indium, gallium, and tin.

[0181] In some embodiments, steam is released from the reaction chamber.

[0182] In some embodiments, catalyst composition is directed through an outlet of the reaction chamber after the activated aluminum reacts with water.

[0183] In some embodiments, the reaction chamber does not require an external energy source for heating.

[0184] In some embodiments, the system produces alumina trihydrate in the reaction chamber. In some embodiments, the system produces alumina trihydrate in a separate crystallization chamber. In some embodiments, the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

[0185] In some embodiments, an alumina trihydrate seed crystal is disposed in the interior volume of the crystallization chamber.

[0186] In some embodiments, the system further comprises carbon dioxide gas bubbled through the contents of the reaction chamber and / or crystallization chamber.

[0187] In some embodiments, the ratio of activated aluminum to non-activated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber is about 5%, about 10%, about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, about 90%, about 95%, or about 100%. In some embodiments, the ratio of activated aluminum to nonactivated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber is 100%. In some embodiments, the ratio of activated aluminum to non-activated aluminum source (e.g., metallic aluminum, bauxite ore, etc.) in the reaction chamber less than 5%, less than 10%, less than 15%, or less than 20%. In some embodiments, the ratio of activated aluminum to non-activated aluminum source in the reaction chamber is at least 5%, at least 10%, at least 15%, at least 20%, at least 25%, at least 30%, at least 40%, at least 45%, or at least 50%. In some embodiments, the ratio of activated aluminum to non-activated aluminum source in the reaction chamber is 100%. In some embodiments, the ratio of activated aluminum to nonactivated aluminum source in the reaction chamber is at least 5%.

[0188] In some embodiments, the pH in the reaction chamber is pH 1 1- 15. In some embodiments, the pH in the reaction chamber is pH 11-14. In some embodiments, the hydroxide base is aqueous. In some embodiments, the pH in the reaction chamber is 12-14. In some embodiments, the pH in the reaction chamber is pH 14 or below. In some embodiments,the hydroxide is at its saturation point in the reaction chamber. In some embodiments, the w / w ratio of a hydroxide base to water in the reaction chamber is 1 : 1

[0189] In some embodiments, the temperature in the reaction chamber is about 100 °C to about 200 °C. In some embodiments, the pressure in the reaction chamber is about 1 bar to about 35 bar. In some embodiments, the pressure in the reaction chamber is about 1 bar to about 15 bar.

[0190] In some embodiments, the reaction chamber is configured to produce alumina trihydrate at a rate of 10 kg / hour, 20 kg / hour, 30 kg / hour, 40 kg / hour, 50 kg / hour, 100 kg / hour, 200 kg / hour, 300 kg / hour, 400 kg / hour, 500 kg / hour, or 1 ton / hour. In some embodiments, the method comprises producing alumina trihydrate and / or alumina at a rate of at least 10 kg / hour.Crystallization chamber

[0191] Provided herein are systems for producing alumina trihydrate and / or alumina that comprise a crystallization chamber. In some embodiments, the crystallization chamber comprises an interior volume and exterior wall. In some embodiments, the exterior wall comprises a first product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide outlet. In some embodiments, the exterior wall further comprises a carbon dioxide input in fluid communication with a source of carbon dioxide and an outlet configured to release carbonate (e.g., sodium carbonate). In some embodiments, the first product inlet is configured to deliver aluminate liquor from the reaction chamber to the interior volume of the crystallization chamber. In certain embodiments, the carbon dioxide is bubbled through the contents of the crystallization chamber. In some embodiments, the product outlet is configured to remove product (e.g., alumina trihydrate) from the system. In some embodiments, the aqueous hydroxide outlet is configured to direct aqueous hydroxide from the interior volume of the crystallization chamber to the interior volume of the reaction chamber.

[0192] In some embodiments, the interior volume of the crystallization chamber is at a different temperature and / or pressure compared to the temperature and / or pressure of the reaction chamber. In some embodiments, the interior volume of the crystallization chamber is at a lower temperature and / or pressure compared to the temperature and / or pressure of the interior volume of the reaction chamber.

[0193] In some embodiments, the aluminate liquor is disposed within the interior volume of the crystallization chamber. In some embodiments, an alumina trihydrate seed crystal isdisposed within the interior of the crystallization chamber. In some embodiments, carbon dioxide gas is bubbled through the liquor, thereby producing carbonate (e.g., sodium carbonate).Steam separator

[0194] Provided herein are systems for producing alumina trihydrate and / or alumina that comprise a steam separator. In some embodiments, the steam separator is configured to separate steam from hydrogen produced by the aluminum water reaction or reduce the steam content of hydrogen gas and steam mixture produced by the aluminum water reaction. In some embodiments, the steam separator is in fluid with a source of hydrogen and / or steam. In some embodiments, the steam separator is in fluid communication with a steam outlet and / or hydrogen outlet of the reaction chamber.

[0195] In some embodiments, the steam separator is configured to separate steam from hydrogen produced in the reactor using any known gas separation process including but not limited to pressure swing adsorption, vacuum swing adsorption, membrane separation, temperature swing adsorption, or cryogenic distillation, or any variation thereof. In some embodiments, the gas separation methods used are well known in the art including those described in Pal, N., and Agarwal, M. International Journal of Hydrogen Energy, Volume 46, Issue 53, 2021, pp 27062-27087; Grande, C. A., International Scholarly Research Network, Volume 2012, Article ID 982934, doi: 10.5402 / 2012 / 982934; Dehdari, L., et al., Chemical Engineering Journal, Volume 450, Part 1, 2022, https: / / doi.Org / 10.1016 / j.cej.2022.13791 1; and Oh, H., et al., European Journal of Inorganic Chemistry, Volume 2016, Issue 27, 2016, pp 4278- 4289; Chen, X. Y., RSC Advances, 2015, 5, 24399-24448; which are herein incorporated by reference in their entirety.

[0196] In some embodiments, the steam separator reduces the steam content of a mixture of hydrogen and steam such that the ratio of hydrogen to steam in the mixture is about 15%, about 20%, about 25%, about 30%, about 35%, about 40%, about 45%, about 50%, about 55%, about 60%, about 65%, about 70%, about 75%, about 80%, about 85%, or about 90%. In some embodiments, ratio of hydrogen to steam in the mixture is about 15% or about 20%.Heat Source

[0197] Provided herein are systems for producing alumina that comprise a heat source for calcining the alumina trihydrate to produce alumina. In some embodiments, the heat source comprises an interior volume and an exterior wall. In some embodiments, the exterior wall comprises a second product inlet in fluid communication with the first product outlet of thereaction chamber or the second product outlet of the crystallization chamber. In some embodiments, the heat source is a kiln. In some embodiments, the heat source is configured to reach temperatures of 1400 K to 1500 K in the interior volume. In some embodiments, the kiln is in thermal communication with a combustion chamber comprising an interior volume and exterior wall. In some embodiments, the exterior wall comprises a hydrogen inlet configured to deliver hydrogen and / or a mixture of hydrogen and steam to the interior volume of the combustion chamber and an exhaust outlet configured to remove combustion products from the interior volume of the combustion chamber. In some embodiments, the hydrogen inlet is in fluid communication with a hydrogen outlet of a device or system described herein. In some embodiments, the heat source is heated by the combustion of hydrogen.

[0198] FIG. 1 describes systems of the present disclosure, comprising a reactor vessel, in which activated aluminum, water, and sodium hydroxide are disposed, and optionally alumina trihydrate crystals, bauxite, non-activated metallic aluminum, and / or other aluminum-containing compounds are disposed. Hydrogen and steam are permitted to exit the reaction chamber as the contents undergo reaction. The final alumina trihydrate reaction product and any liquid metal catalysts used to speed up the reaction may also be removed. Periodically, NaOH may be added to control the pH within the reaction chamber. In these embodiment, the reaction chamber is a single chamber which may include a stirring mechanism. The reactor embodiment described here may be operated in batch or continuous mode operations.

[0199] FIG. 2 describes other systems of the present disclosure, similar to the embodiments described by FIG. 1 , with an additional chamber physically separated from the reaction chamber, which receives the contents of the reaction chamber, and where the crystallization and / or precipitation of alumina trihydrate may occur at different timescales, as well as different pressures and temperatures, from the reaction chamber. In this crystallization chamber, seed alumina trihydrate crystals may be added to nucleate alumina trihydrate formation. The precipitated alumina trihydrate may be removed and the remaining aqueous NaOH solution be fed back into the primary reaction vessel. Hydrogen, steam, and catalyst are otherwise released from the reaction vessel in the way described in FIG. 1.

[0200] FIG. 3 describes other systems of the present disclosure similar to the systems described by FIG. 1 , with the addition of carbon dioxide gas which is bubbled through the reaction solution to form sodium carbonate, thereby reducing the pH in the reaction chamber and causing alumina trihydrate to precipitate. The alumina trihydrate and sodium carbonate may beremoved from the reaction chamber and further processed into separate, pure streams of each.The sodium carbonate in this case serves as solid storage of captured carbon dioxide gas, which may come from the combustion of carbon or hydrocarbon compounds elsewhere.

[0201] FIG. 4 describes other systems of the present disclosure similar to the systems described in FIG. 3, but with a separate precipitation chamber, into which carbon dioxide gas is bubbled to form sodium carbonate and solid alumina trihydrate. The precipitation may optionally be carried out at different operating temperatures and pressures from the main reactor.

[0202] FIG. 5 describes embodiments of the disclosure wherein the hydrogen and steam produced by the aluminum-water reaction may be used to heat a kiln (e.g. a rotary kiln) to calcine alumina trihydrate or aluminum oxyhydroxide into alumina. The hydrogen and steam may be mixed in such concentrations that combustion in air or oxygen is not possible. In these cases, the steam may first be condensed as shown here in order to increase the relative concentration of hydrogen in the gas stream to the point where combustion in either air or oxygen is possible. The thermal energy from the steam may be rejected to a heat transfer fluid via a heat exchanger, and the thermal energy may be used to power processes elsewhere.

[0203] FIG. 6 describes an additional embodiment of the steam and hydrogen being used to power a calcination process, wherein a membrane is used to remove a portion of the steam from the a steam / hydrogen mixture to enable the combustion of the remaining hydrogen and steam mixture in air or oxygen to power the kiln.EXAMPLESExample 1 - Single vessel scrap aluminum-fueled Bayer reactor

[0204] An alumina refinery uses scrap aluminum to power the production of alumina from various Bauxite and alumina trihydrate inputs. In a standard Bayer reactor, pure alumina trihydrate is separated from other inputs by first dissolution into an aqueous concentrated NaOH solution (e.g., 6-7 M, the “Bayer liquor”), at elevated temperature (e.g., about 180 °C) and pressure (e.g., about 10 bar). Alumina trihydrate is continually dissolved in this solution and then precipitated out near its saturation concentration either via pure alumina trihydrate crystal addition or introduction of carbon dioxide gas. The pure alumina trihydrate is separated, NaOH is recovered and recycled, and the various impurities are separated out as well as a single stream.

[0205] This example describes a modified Bayer reactor which also ingests aluminum that is previously made water-reactive by means of a surface treatment of a low-melting point liquidmetal alloy (e.g. a composition comprising gallium and indium). The exothermic aluminum- water reaction that proceeds in the aqueous NaOH Bayer liquor releases direct thermal energy, hydrogen gas, and produces alumina trihydrate. The thermal energy released by the aluminum- water reaction powers the Bayer process by maintaining the temperature and pressure needed for the dissolution of alumina trihydrate in the Bayer liquor. The hydrogen and any additional steam produced by the aluminum- water reaction are then released from the reactor to power auxiliary processes in the plant - e.g. generating electricity via a fuel cell, generating mechanical power and / or electricity via turbomachinery, or combusted to provide high temperature heat (750-1500 K) for external processes in the plant like alumina calcination. To aid in flexible utilization of the hydrogen and steam produced, some amount of the steam can be separated from the output gas stream by either a membrane or via condensation, for example. The alumina trihydrate formed in the aluminum-water reaction serves as additional feedstock for the Bayer process and its downstream processes. Under the reaction conditions present in this reactor, some amount of raw scrap aluminum (i.e. which has not previously been treated with any catalytic additives) may also be added to the Bayer reactor to help control the average kinetics, giving plant operators additional operational flexibility.Example 2 - Generation of aqueous aluminate from activated aluminum

[0206] This example describes the generation of aqueous aluminate from reactions of activated aluminum with water in aqueous NaOH solutions.Experiment 1

[0207] To an Erlenmeyer flask was added 50 mL of pH 14 NaOH aqueous solution. To the flask was further added 1.5 g of activated aluminum, and the resulting mixture was stirred on a stir plate at room temperature. The activated aluminum reacted with the water in the NaOH aqueous solution, resulting in the release of hydrogen gas and heat. After the reaction was complete, as evidenced by no further gas evolution, the solution appeared clear and no activated aluminum remained, indicating full digestion of the activated aluminum into dissolved aluminate species. The only visible solid was the catalyst from the activated aluminum, which coalesced into a single liquid metal droplet. Following reaction, the solution remained clear, although the color changed to a shade of orange over the course of 24 hours. The color change may be due to contaminants introduced by the stir bar, or an indication that other metallicspecies (e.g., metals that comprise the catalyst) were dissolving in the aqueous solution. The experiment was performed in triplicate, in parallel.

[0208] An image of the reaction mixtures 30 minutes after addition of the activated aluminum is provided as FIG. 7. An image of one of the reaction mixtures one day after reaction initiation is provided as FIG. 8.Experiment 2

[0209] A second experiment was performed at a higher volume and a larger activated aluminum to NaOH solution ratio relative to Experiment 1. To a round-bottom flask was added 250 mL of pH 14 NaOH aqueous solution. To the flask was further added 15 g of activated aluminum, and the resulting mixture was stirred on a stir plate at room temperature. The activated aluminum reacted with the water in the NaOH aqueous solution, resulting in the release of hydrogen and heat. After 30 minutes, the mixture appeared somewhat clear and gray, with evidence of catalyst coalescing and swirling along the bottom of the flask. However, the solution appeared cloudier than the solutions of Experiment 1 , which used a lower activated aluminum to solution ratio, implying that the solution may have reached aluminate saturation (e.g., resulting in precipitation of aluminum hydroxide). The solution color changed to orange over the course of one hour from beginning the reaction. As discussed in Experiment 1, the color change may be due to contaminants introduced by the stir bar, or an indication that other metallic species (e.g., metals that comprise the catalyst) were dissolving in the aqueous solution. One day after reaction initiation, the solution appeared opaque and white (with a slight orange hue). This may indicate that some amount of the aluminate ions precipitated out as solid aluminum hydroxide.

[0210] An image of the reaction mixture 30 minutes after addition of the activated aluminum is provided as FIG. 9. An image of the reaction mixture one hour after reaction initiation is provided as FIG. 10. An image of the reaction mixture one day after reaction initiation is provided as FIG. 1 1.Equivalents and Scope

[0211] In the claims articles such as “a,” “an,” and “the” may mean one or more than one . include “or” between one or more members of a group are considered satisfied if one, more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process unless indicated to the contrary or otherwise evident from the context. Provide herein are embodiments in which exactly one member of the group is present in, employed in, or otherwise relevant to a given product or process. Provided herein are embodiments in which more than one, or all of the group members are present in, employed in, or otherwise relevant to a given product or process.

[0212] Furthermore, the inventions provided herein encompass all variations, combinations, and permutations in which one or more limitations, elements, clauses, and descriptive terms from one or more of the listed claims is introduced into another claim. For example, any claim that is dependent on another claim can be modified to include one or more limitations found in any other claim that is dependent on the same base claim. Where elements are presented as lists, e.g., in Markush group format, each subgroup of the elements is also disclosed, and any element(s) can be removed from the group. It should be understood that, in general, where the inventions provided and described herein, or aspects of the inventions described and provided herein, is / are referred to as comprising particular elements and / or features, certain embodiments of the inventions or aspects of the inventions consist, or consist essentially of, such elements and / or features. For purposes of simplicity, those embodiments have not been specifically set forth in haec verba herein. It is also noted that the terms “comprising” and “containing” are intended to be open and permits the inclusion of additional elements or steps. Where ranges are given, endpoints are included. Furthermore, unless otherwise indicated or otherwise evident from the context and understanding of one of ordinary skill in the art, values that are expressed as ranges can assume any specific value or sub-range within the stated ranges in different embodiments of the inventions described and provided herein, to the tenth of the unit of the lower limit of the range, unless the context clearly dictates otherwise.

[0213] This application refers to various issued patents, published patent applications, journal articles, and other publications, all of which are incorporated herein by reference. If there is a conflict between any of the incorporated references and the instant specification, the specification shall control. In addition, any particular embodiment that falls within the prior art may be explicitly excluded from any one or more of the claims. Because such embodiments are deemed to be known to one of ordinary skill in the art, they may be excluded even if theexclusion is not set forth explicitly herein. Any particular embodiment can be excluded from any claim, for any reason, whether or not related to the existence of prior art.

[0214] Each numerical value presented herein is contemplated to represent a minimum value or a maximum value in a range for a corresponding parameter. Accordingly, when added to the claims, the numerical value provides express support for claiming the range, which may lie above or below the numerical value, in accordance with the teachings herein. Every value between the minimum value and the maximum value within each numerical range presented herein (including any minimum, nominal, and maximum values shown in any tables), is contemplated and expressly supported herein, subject to the number of significant digits expressed in each particular range. The application expressly contemplates the ranges between the minimum and nominal values, nominal and maximum values, and minimum and maximum values.

[0215] Those skilled in the art will recognize or be able to ascertain using no more than routine experimentation many equivalents to the specific embodiments described herein. The scope of the present embodiments described herein is not intended to be limited to the above Description, but rather is as set forth in the appended claims. Those of ordinary skill in the art will appreciate that various changes and modifications to this description may be made without departing from the spirit or scope of the present inventions, as defined in the following claims.

Claims

CLAIMS1. A method of producing alumina trihydrate (Al(0H)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A100H), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([Al(0H)4]'), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

2. A method of producing alumina trihydrate (Al(0H)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A100H), wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([Al(0H)4] ), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

3. A method of producing alumina (AI2O3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition; a non-activated aluminum source; water; and a hydroxide base in a reaction chamber to form a mixture; wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate (Al(0H)3) and / or aluminum oxyhydroxide (A100H), wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([Al(0H)4] ), and wherein the non-activated aluminum source is converted to aluminate, thereby producing a liquor from the mixture; precipitating alumina trihydrate from the liquor; and heating the alumina trihydrate thereby producing alumina.

4. A method of producing alumina trihydrate (Al(0H)3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([Al(0H)4] ); and precipitating alumina trihydrate (Al(0H)3) from the liquor.

5. A method of producing alumina trihydrate (Al(OH)s), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([Al(0H)4] ); and precipitating alumina trihydrate ( Al(OHh) from the liquor.

6. A method of producing alumina (AI2O3), the method comprising: combining at least activated aluminum comprising aluminum and a catalyst composition, a non-activated aluminum source, water, and a hydroxide base in a reaction chamber, thereby producing a liquor comprising aqueous aluminate ([Al(0H)4] ); precipitating alumina trihydrate (Al(0H)3) from the liquor; and heating the alumina trihydrate thereby producing alumina.

7. The method of any one of claims 1-6, wherein the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide.

8. The method of any one of claims 1-7, wherein the hydroxide base is sodium hydroxide.

9. The method of any one of claims 2, 3, 5, and 6-8, wherein the non-activated aluminum source is added to the reaction chamber in one portion.

10. The method of any one of claims 2, 3, 5, and 6-8, wherein the non-activated aluminum source is added to the reaction chamber in multiple portions.

11. The method of any one of claims 2, 3, 5, and 6-8, wherein the non-activated aluminum source is added to the reaction chamber at least every 30 seconds.

12. The method of any one of claims 2, 3, 5, and 6-8, wherein the non-activated aluminum source is added to the reaction chamber continuously.

13. The method of any one of claims 1-12, wherein the hydroxide base and water are added to the reaction chamber prior to addition of the activated aluminum.

14. The method of any one of claims 1-3 and 9-13, further comprising stirring the mixture in the reaction chamber.

15. The method of any one of claims 4-14, further comprising stirring the activated aluminum comprising aluminum and a catalyst composition, the water, and the hydroxide base in the reaction chamber.

16. The method of any one of claims 2, 3, and 5-15, wherein the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, alumina (AI2O3), and metallic aluminum.

17. The method of claim 16, wherein the metallic aluminum is substantially pure (e.g., >99% pure, >98% pure, >97% pure, >96% pure, or >95% pure).

18. The method of claim 16, wherein the metallic aluminum contains impurities.

19. The method of any one of claims 1-18, wherein the catalyst composition is a low-melting liquid metal alloy.

20. The method of any one of claims 1-19, wherein the catalyst composition comprises gallium and / or indium.

21. The method of any one of claims 1-20, wherein the catalyst composition is a non-eutectic alloy comprising bismuth, tin, indium, and gallium.

22. The method of any one of claims 1-19, wherein the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium.

23. The method of any one of claims 1-19, wherein the catalyst composition comprises gallium and indium.

24. The method of any one of claims 1-19, wherein the catalyst composition comprises gallium, indium, and tin.

25. The method of any one of claims 1-24, wherein steam is released in the reaction chamber.

26. The method of any one of claims 1-25, further comprising recovering the catalyst composition.

27. The method of any one of claims 1-26, wherein at least 95% of the catalyst composition is recoverable.

28. The method of any one of claims 2, 3, and 5-27, wherein the ratio of non-activated aluminum to activated aluminum in the reaction chamber is 100%.

29. The method of any one of claims 2, 3, and 5-27, wherein the ratio of non-activated aluminum to activated aluminum in the reaction chamber is at least 5%.

30. The method of any one of claims 1-29, further comprising maintaining the pH in the reaction chamber at pH 12-14.

31. The method of any one of claims 1-29, further comprising maintaining the pH in the reaction chamber at pH 11-15.

32. The method of any one of claims 1-31, wherein the hydroxide is at its saturation point in the mixture.

33. The method of claim 30 or 31 , wherein maintaining the pH of the reaction mixture comprises sequential addition of hydroxide base to the reaction mixture.

34. The method of any one of claims 1-33, further comprising controlling the pH in order to influence the relative concentrations of aluminum oxyhydroxide and alumina trihydrate produced by the reaction of the activated aluminum with water.

35. The method of any one of claims 1-34, further comprising maintaining the temperature in the reaction chamber at about 100 °C to about 200 °C.

36. The method of any one of claims 1-35, further comprising maintaining the pressure in the reaction chamber at about 1 bar to about 35 bar.

37. The method of any one of claims 1-3 and 7-36, wherein the heat released by the reaction of the activated aluminum and water increases and / or maintains the temperature and / or pressure in the reaction chamber.

38. The method of any one of claims 4-36, wherein heat is released by reaction of the activated aluminum and water, and the heat increases and / or maintains the temperature and / or pressure in the reaction chamber.

39. The method of any one of claims 2, 3, and 7-36, wherein the conversion of the nonactivated aluminum source to aluminate proceeds without an external heat input.

40. The method of any one of claims 5-36, wherein the non-activated aluminum source is converted to aluminate without an external heat input.

41. The method of any one of claims 2, 3, and 7-36, wherein addition of the activated aluminum reduces the required external heat input for conversion of the non-activated aluminum source to the aluminate.

42. The method of any one of claims 5-36, wherein the non-activated aluminum source is converted to aluminate, and addition of the activated aluminum reduces the required external heat input for conversion of the non-activated aluminum source to the aluminate.

43. The method of any one of claims 1-42, wherein the alumina trihydrate is precipitated from the liquor in the reaction chamber.

44. The method of any one of claims 1-42, wherein the alumina trihydrate is precipitated from the aluminate liquor in a separate crystallization chamber.

45. The method of any one of claims 1-44, wherein the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

46. The method of any one of claims 1-45, wherein precipitating the alumina trihydrate comprises adding a seed crystal to the reaction chamber or crystallization chamber.

47. The method of any one of claims 1-45, wherein precipitating the alumina trihydrate comprises bubbling carbon dioxide gas through the aluminate liquor and further produces carbonate (e.g., sodium carbonate).

48. The method of any one of claims 1-47, further comprising filtering impurities from the liquor prior to precipitation of aluminate.

49. The method of any one of claims 1-48, wherein Al(0H)3 produced by reaction of the activated aluminum with water is precipitated from the liquor.

50. The method of any one of claims 3 and 6-49, wherein the alumina trihydrate is heated to a temperature of 1400 K to 1500 K, thereby producing alumina.

51. The method of any one of claims 1-50, wherein the hydrogen gas and / or steam is used to power a separate process.

52. The method of any one of claims 1-51, wherein the hydrogen is used to generate electricity via a fuel cell.

53. The method of any one of claims 1-52, wherein the steam is used to power a turbine.

54. A system for producing alumina trihydrate (Al(0H)3), the system comprising: a device for producing alumina trihydrate (A1(OH)3) comprising a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet in controlled fluid communication with a source of activated aluminum wherein the activated aluminum comprises aluminum and a catalyst composition, a first water inlet in controlled fluid communication with a source of water, a hydroxide base inlet in controlled fluid communication with a source of hydroxide base, a gravity-fed catalyst composition outlet, a steam outlet, a hydrogen outlet, and a first product outlet, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, and wherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

55. The system of claim 54, further comprising: a crystallization chamber comprising a first product inlet in fluid communication with the first product outlet of the device, a second water inlet, a second product outlet, and an aqueous hydroxide outlet.

56. The system of claim 54 or 55, further comprisinga heat source for calcining the alumina trihydrate to produce alumina, comprising an interior volume and exterior wall, wherein the exterior wall comprises a second product inlet in fluid communication with the first product outlet of the reaction chamber or the second product outlet of the crystallization chamber.

57. The system of claim 56, wherein the heat source is a kiln.

58. A system comprising a reaction chamber and instructions therefor configured to produce alumina trihydrate (Al(OH)s) by: combining at least activated aluminum comprising aluminum and a catalyst composition, water, and a hydroxide base in the reaction chamber to form a mixture, wherein the activated aluminum reacts with the water in the mixture to produce heat, hydrogen gas, and alumina trihydrate and / or aluminum oxyhydroxide (A100H), and wherein the alumina trihydrate and / or aluminum oxyhydroxide in the mixture are further converted to aqueous aluminate ([Al(0H)4]'), thereby producing a liquor from the mixture; and precipitating alumina trihydrate from the liquor.

59. The system of claim 58, further comprising a heat source, the system and instructions configured to produce alumina (AI2O3) by: heating the alumina trihydrate with the heat source thereby producing alumina.

60. The system of any one of claims 54-59, wherein the system precipitates the alumina trihydrate in the reaction chamber.

61. The system of any one of claims 54-59, wherein the system further comprises a crystallization chamber separate from the reaction chamber configured to precipitate the alumina trihydrate therein.

62. A system for producing alumina trihydrate (A1(OH)3) and / or alumina (AI2O3), the system comprising a reaction chamber comprising an interior volume and exterior wall, wherein the exterior wall comprises an activated aluminum inlet extending therethrough, a first water inlet extending therethrough, a hydroxide base inlet extending therethrough, a gravity-fed catalyst composition outlet extending therethrough, a steam outlet extending therethrough, a hydrogen outlet extending therethrough and a first product outlet extending therethrough, wherein the outlets are arranged such that the steam outlet and hydrogen outlet are in an upper half of the reaction chamber when the catalyst composition outlet is in a lower half of the reaction chamber sufficient for gravity to direct catalyst composition through the catalyst composition outlet, wherein at least activated aluminum comprising aluminum and a catalyst composition, water,and hydroxide base are disposed within the interior volume, and wherein the device further comprises thermal insulation, a heat sensor, a pressure sensor, and an impeller and / or agitator.

63. The system of claim 62, further comprising a non-activated aluminum source or nonactivated aluminum.

64. The system of claim 62 or 63, further comprising an alumina trihydrate crystallization chamber comprising a product inlet in fluid communication with the first product outlet of the reaction chamber, a second water inlet, a second product outlet, and an aqueous hydroxide base outlet, wherein a liquor comprising aluminate ([Al(0H)4] ) is disposed within the interior volume of the crystallization chamber.

65. The system of claim 63 or 64, further comprising a heat source, wherein the heat source is a kiln or another source of heat of the alumina trihydrate crystallization chamber or reaction chamber.

66. The system of any one of claims 54-65, wherein the hydroxide base is selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide, and ammonium hydroxide.

67. The system of any one of claims 54-65, wherein the hydroxide base is sodium hydroxide.

68. The system of any one of claims 62-67, wherein the non-activated aluminum source comprises one or more of bauxite ore, alumina trihydrate, aluminum oxyhydroxide, alumina (AI2O3), and metallic aluminum.

69. The system of claim 68, wherein the metallic aluminum is substantially pure (e.g., >99% pure, >98% pure, >97% pure, >96% pure, or >95% pure).

70. The system of claim 68, wherein the metallic aluminum contains impurities.

71. The system of any one of claims 54-70, wherein the catalyst composition is a low- melting liquid metal alloy.

72. The system of any one of claims 54-71, wherein the catalyst composition comprises gallium and / or indium.

73. The system of any one of claims 54-70, wherein the catalyst composition is a noneutectic alloy comprising bismuth, tin, indium, and gallium.

74. The system of any one of claims 54-70, wherein the catalyst composition comprises bismuth, tin, and indium and does not comprise gallium.

75. The system of any one of claims 54-70, wherein the catalyst composition comprises gallium and indium.

76. The system of any one of claims 54-70, wherein the catalyst composition comprises gallium, indium, and tin.

77. The system of any one of claims 54-76, wherein steam is released from the reaction chamber.

78. The system of any one of claims 54-77, wherein catalyst composition is directed through the catalyst outlet of the reaction chamber after the activated aluminum reacts with water.

79. The system of any one of claims 54-78, wherein the ratio of non-activated aluminum to activated aluminum in the reaction chamber is 100%.

80. The system of any one of claims 54-78, wherein the ratio of activated aluminum to nonactivated aluminum in the reaction chamber is at least 5%.

81. The system of any one of claims 54-80, wherein the hydroxide base is aqueous.

82. The system of any one of claims 54-81, wherein the pH in the reaction chamber is 12-14.

83. The system of any one of claims 54-81, wherein the pH in the reaction chamber is 11-15.

84. The system of any one of claims 54-83, wherein the hydroxide is at its saturation point in the mixture.

85. The system of any one of claims 54-84, wherein the temperature in the reaction chamber is about 100 °C to about 200 °C.

86. The system of any one of claims 54-85, wherein the pressure in the reaction chamber is about 1 bar to about 35 bar.

87. The system of any one of claims 54-86, wherein the reaction chamber does not require an external energy source for heating.

88. The system of any one of claims 54-87, wherein the device produces alumina trihydrate in the reaction chamber.

89. The system of any one of claims 54-87, wherein the device produces alumina trihydrate in a separate crystallization chamber.

90. The system of any one of claims 54-89, wherein the temperature and / or pressure in the crystallization chamber is different from the temperature and / or pressure in the reaction chamber.

91. The system of any one of claims 54-90, wherein an alumina trihydrate seed crystal is disposed in the interior volume of the crystallization chamber.

92. The system of any one of claims 64-90, further comprising carbon dioxide gas bubbled through the contents of the reaction chamber and / or crystallization chamber.

93. The system of any one of claims 54-92, further comprising a filter for removing impurities.

94. The system of any one of claims 54-93, wherein the hydrogen gas and / or steam generated by the device is used to power a separate process.

95. The system of any one of claims 54-94, wherein the hydrogen is used to generate electricity via a fuel cell.

96. The system of any one of claims 54-95, wherein the steam is used to power a turbine.

97. A method of calcining alumina trihydrate (Al(0H)3) and / or aluminum oxyhydroxide (A100H) to produce alumina (AI2O3), the method comprising heating the alumina trihydrate and / or aluminum oxyhydroxide in a heat source, wherein the heat source is partially or fully heated by the combustion of hydrogen produced by the method of any one of claims 1-53 or the system of any one of claims 54-96.

98. The method of claim 97, wherein a quantity of steam is removed from the hydrogen prior to combustion.

99. The method of claim 98, wherein steam is removed by condensation or membrane separation.

100. A method, system, or device comprising any feature or aspect or combination thereof shown in any figure or described in any disclosure or example or portion thereof of the present application that is configured to produce alumina trihydrate (Al(0H)3) and / or alumina (AI2O3).

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