Methods for activating aluminum

Abstract

Described herein are methods for producing water-reactive aluminum compositions.

Description

[0001] METHODS FOR ACTIVATING ALUMINUM

[0002] CROSS-REFERENCE TO RELATED APPLICATION

[0003]

[0001] This application claims the benefit of and priority to U.S. Provisional Patent Application No. 63 / 672,940, filed on July 18, 2024, the disclosure of which is hereby incorporated by reference in its entirety for all purposes.

[0004] BACKGROUND

[0005]

[0002] 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 the aluminum with water to form hydrogen and heat as described in Reaction 1 or Reaction 2.

[0006] • Al + 2 H2O — > 1.5 H2 + AIO(OH) + Qieaction (Reaction 1)

[0007] • Al + 3 H2O — 1.5 H2 + Al(0H)3 + Qreaction (Reaction 2)

[0008]

[0003] Untreated aluminum will typically not react with water due to the highly passivating oxide layer that forms on its surface. However, the oxide layer may be disrupted by an appropriate catalyst, thereby activating the aluminum to make it water-reactive.

[0009]

[0004] There exists a need to automate activation of aluminum, as well as to optimize activation parameters for process efficiency and performance of the resulting activating aluminum.

[0010] SUMMARY

[0011]

[0005] In one aspect, disclosed herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 24 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the method generates a water-reactive aluminum composition having peak reactivity.

[0012]

[0006] In another aspect, disclosed herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 72 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the aluminum or alloy thereof is scrap aluminum, wherein the scrap aluminum has been shredded to form scrap aluminum shreds, and wherein the scrap aluminum shreds have been compressed into scrap aluminum pellets prior to contacting the aluminum or alloy thereof with the activating metal alloy, wherein the method generates a water-reactive aluminum composition having peak reactivity.

[0013]

[0007] In another aspect, disclosed herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with a first activating metal alloy comprising gallium to provide a first mixture; contacting the first mixture with an activating metal or a second activating metal alloy having a lower gallium content by mass than the first activating metal alloy to provide a water-reactive aluminum composition having the activating metal alloys disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs.

[0014]

[0008] In another aspect, disclosed herein is a method of activating aluminum or an alloy thereof, the method comprising contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a water- reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, and wherein the aluminum or alloy thereof comprises aluminum foils.

[0015] BRIEF DESCRIPTION OF THE DRAWINGS

[0016]

[0009] FIG. 1 is a flowchart showing a method for activating aluminum using an activating metal alloy. T = temperature; t = time.

[0017]

[0010] FIG. 2 is a flowchart showing a method for activating aluminum using an activating metal alloy, including specific time and temperature process parameters. [Oil] FIG. 3 is a flowchart showing a method for activating aluminum using an activating metal alloy, including specific time and temperature process parameters.

[0018]

[0012] FIG. 4 is a flowchart showing a method for activating aluminum using an activating metal alloy, including specific time and temperature process parameters.

[0019]

[0013] FIG. 5 is a flowchart showing a method for activating aluminum using a secondary, non- reactive activating metal alloy recovered from a previous reaction of activated aluminum with water. T = temperature; t = time.

[0020]

[0014] FIG. 6 is a flowchart showing a method for activating aluminum using a secondary, reactive activating metal alloy recovered from a previous reaction of activated aluminum with water.

[0021]

[0015] FIG. 7 is reaction data for Sample T, fuel activated using virgin catalyst and cured for 50 °C. The vertical dashed lines represent when water (10 mL or 45 mL, as annotated) was added to the fuel.

[0022]

[0016] FIG. 8 is reaction data for Sample U, fuel activated using recovered and non-reactive catalyst from a previous lot of fuel. The vertical dashed lines represent when water (5 mL or 45 mL, as annotated) was added to the fuel.

[0023]

[0017] FIG. 9 is reaction data for Sample V, fuel activated using recovered and reactive catalyst from a previous lot of fuel. The vertical dashed lines represent when water (10 mL or 45 mL, as annotated) was added to the fuel.

[0024]

[0018] FIG. 10 is comparative yield data for Sample S and Sample T, cured at 50 °C and room temperature respectively.

[0025]

[0019] FIG. 11 is comparative average power data for Sample S and Sample T, cured at 50 °C and room temperature respectively.

[0026]

[0020] FIG. 12 is reaction data for Sample X, fuel activated under nitrogen gas. The vertical dashed lines represent when water (10 mL or 45 mL, as annotated) was added to the fuel.

[0027]

[0021] FIG. 13 is reaction data for Sample Y, fuel activated under ambient air. The vertical dashed lines represent when water (10 mL or 45 mL, as annotated) was added to the fuel.

[0028] DETAILED DESCRIPTION

[0029]

[0022] In previous processes incorporating activated aluminum as an energy source, typically only one form of aluminum feedstock has been activated. However, it may be desirable to intentionally mix feedstocks or be tolerant of mixed feedstocks (e.g., aluminum from various sources and / or aluminum pieces having various forms).

[0030]

[0023] Additionally, previous processes required a “curing time” of about 24-72 hours after activation of substantially pure aluminum with an activating metal alloy catalyst to allow for diffusion of the catalyst within the aluminum, before the aluminum reached peak reactivity. For larger aluminum pellets and / or pellets containing multiple particles (e.g., shredded scrap aluminum pressed into pellets), the curing may exceed 72 hours in previous processes. This required curing time increases the quantity of valuable catalyst that is locked-up in non-useable fuel. It would therefore be desirable to decrease or eliminate this curing time.

[0031]

[0024] To avoid these shortcomings, it is desirable to develop methods of activating aluminum that are rapid and robust.

[0032]

[0025] The present disclosure provides processes for activating aluminum with the use of an activating metal alloy (catalyst). The contemplated processes may make aluminum reactive with water or steam as described in Reaction 1 or Reaction 2.

[0033]

[0026] Applications of the contemplated processes may be used for primary aluminum, secondary aluminum, or any feedstock containing metallic aluminum. Some examples of various applicable feedstock include but are not limited to: pure aluminum, aluminum alloys, dross from aluminum smelting processes, dross from aluminum recycling processes, aluminum components that don’t meet product specifications or pass quality control, aluminum foils, and household waste food containers. Exact process conditions may be tuned depending on the chemistry, microstructure and physical morphology of the feedstock.

[0034]

[0027] The term “non-eutectic”, as used herein, refers to an alloy where the melting point of the alloy is higher than the melting point of at least one of the constituent metals.

[0035]

[0028] The term “microstructure” of aluminum, as used herein, refers to an arrangement of crystalline aluminum grains, intermetallic phases, and crystalline defects forming a larger aluminum particle or object, with grain boundaries at the interfaces between the individual aluminum grains.

[0036]

[0029] The terms “catalyst” and “activating metal alloy”, are used interchangeably herein and refer to a metallic alloy capable of diffusing in metallic aluminum and disrupting the superficial and interstitial aluminum oxide of metallic aluminum.

[0037]

[0030] As used herein, a catalyst or activating metal alloy that consists “essentially of’ one or more components is to be understood as consisting of said components and no more than trace amounts of any additional components (e.g., less than 0.5% by mass of each additional component).

[0038]

[0031] The term “feedstock”, as used herein, refers to any starting material which contains metallic aluminum including but not limited to pure aluminum, aluminum alloys, primary or secondary aluminum, and waste product which contains a significant amount (e.g., at least 5%, 10%, 20%, 30%, 40%, 50%, 60%, 70%, or 80% by weight) of metallic aluminum. Feedstock may contain additional components including but not limited to plastic, other metals, ceramics, and organic compounds.

[0039]

[0032] The term “activated fuel”, as used herein, refers to an activated aluminum composition formed by treating aluminum or an alloy thereof with an activating metal alloy. When water is introduced to the activated fuel, the aluminum disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs.

[0040]

[0033] The term “room temperature” as used herein refers to 20 °C.

[0041]

[0034] The term “elevated temperature” as used herein refers to any temperature above 20 °C.

[0035] The term “virgin alloy” as used herein refers to an activating metal alloy that has not previously been recovered or recycled from a previous reaction mixture, e.g., a reaction mixture resulting from Reaction 1 or Reaction 2.

[0042]

[0036] The term “aluminum foil” as used herein refers to aluminum in the form of a sheet having a thickness of less than or equal 0.2 mm.

[0043]

[0037] The term “peak reactivity” as used herein refers to the reactivity of a water-reactive aluminum composition that cannot be increased through additional curing time. Curing refers to the process by which an activating metal alloy applied to the surface of an aluminum-containing composition is allowed to diffuse through the bulk of the aluminum-containing composition over time to render the aluminum-containing composition reactive with water, and may optionally include heating and / or agitation of the surface-treated aluminum-containing composition. In some embodiments, the water-reactive aluminum compositions described herein achieve peak reactivity using a method of activating aluminum described herein. Water-reactive aluminum compositions described herein having peak reactivity may have an average power output of greater than 1.0 kW upon reaction with water and / or specific energies of greater than or equal to 6.5 kWh / kg.

[0044]

[0038] 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%, or 15% 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.”

[0045]

[0039] As used herein an average particle diameter may be described in terms of the mean particle size characterized by any one of a sphere of ideal volume (dv), a sphere of identical weight (dw), a sphere of identical minimum length (dmin), a sphere passing same sieve aperture (dsieve), a sphere of identical maximum length, a sphere of identical surface area (ds), a sphere that diffuses at the same rate as the particle in a fluid (dh), or a sphere of identical sedimentation rate (dsed). The type of characterization of particle size may be determined by a skilled person in the art depending on how the particles are formed and their size. In a non-limiting example, pellet shaped particles having a diameter of 20 mm may be characterized by a sphere passing same sieve aperture (dsieve).

[0046]

[0040] As used herein an “average” size of a population of particles may be described in terms of the percentile of particles smaller than a given diameter. For example, a D10 value, or the 10th percentile, signifies the particle size below which 10% of the population's particles are found. In another example, the D50 value is the 50thpercentile, also known as the median particle size, is the size at which 50% of the population’s particles consists of particles smaller than this size. In a further example, the D90 value, or the 90th percentile, indicates the particle size below which 90% of the population's particles are located. In some embodiments, one percentile is used to define the average particle size. In some embodiments, all three percentiles are used to describe the size distribution of particles within a population.

[0047]

[0041] Many different techniques known to those skilled in the art may be used to characterize the average diameter of a population and the distribution of particle sizes within a population. For example, a population of particles may be passed through one or more sieves, each sieve progressively smaller mesh sizes (dsieve).

[0048] Methods of Activating Aluminum

[0042] In one aspect, provided herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, and heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 24 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the method generates a water-reactive aluminum composition having peak reactivity.

[0049]

[0043] In another aspect, provided herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 72 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the aluminum or alloy thereof is scrap aluminum, wherein the scrap aluminum has been shredded to form scrap aluminum shreds, and wherein the scrap aluminum shreds have been compressed into scrap aluminum pellets prior to contacting the aluminum or alloy thereof with the activating metal alloy, wherein the method generates a water-reactive aluminum composition having peak reactivity.

[0050]

[0044] In some embodiments, the scrap aluminum pellets have an average diameter of about 10- 30 mm, about 30-50 mm, about 50-70 mm, or about 70- 100 mm. In some embodiments, the scrap aluminum pellets have an average diameter of about 10 mm, about 15 mm, about 20 mm, about 25 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 certain embodiments, the scrap aluminum pellets have an average diameter of about 20 mm. In certain embodiments, the scrap aluminum pellets have an average diameter of about 100 mm. In some embodiments, the scrap aluminum pellets have an average weight of about 0.5 g, about 1.0 g, about 1.5 g, about 2 g, about 3 g, about 4 g, about 5 g, about 10 g, about 20 g, about 30 g, about 40 g, about 50 g, about 100 g, about 200 g, about 300 g, about 400 g, or about 500 g per pellet. In certain embodiments, the scrap aluminum pellets have an average weight of about 1.5 g per pellet. As used herein the “pellets” are particles and may be characterized in terms of diameter and distribution of diameters using techniques commonly known to those skilled in the art.

[0051]

[0045] In some embodiments, the mixture is heated at a temperature of about 40 °C to about 60 °C.

[0052]

[0046] In some embodiments, the first temperature is about 125 °C to about 135 °C. In some embodiments, the first temperature is about 85 °C to about 95 °C. In some embodiments, the first temperature is about 40 °C to about 60 °C. In some embodiments, the first temperature is about 20 °C to about 30 °C. In some embodiments, the second temperature is about 40 °C to about 90 °C. In some embodiments, the second temperature is about 40 °C to about 60 °C. In some embodiments, the second temperature is about 25 °C to about 35 °C. In some embodiments, the second temperature is about 20 °C to about 30 °C. In some embodiments, the first temperature is the same as the second temperature. In some embodiments, the first temperature is higher than the second temperature. In some embodiments, the first temperature is lower than the second temperature.

[0053]

[0047] In some embodiments, the first temperature is about 20 °C. In some embodiments, the first temperature is about 25 °C. In some embodiments, the first temperature is about 30 °C. In some embodiments, the first temperature is about 35 °C. In some embodiments, the first temperature is about 40 °C. In some embodiments, the first temperature is about 45 °C. In some embodiments, the first temperature is about 50 °C. In some embodiments, the first temperature is about 55 °C. In some embodiments, the first temperature is about 60 °C. In some embodiments, the first temperature is about 65 °C. In some embodiments, the first temperature is about 70 °C. In some embodiments, the first temperature is about 75 °C. In some embodiments, the first temperature is about 80 °C. In some embodiments, the first temperature is about 85 °C. In some embodiments, the first temperature is about 90 °C. In some embodiments, the first temperature is about 95 °C. In some embodiments, the first temperature is about 100 °C. In some embodiments, the first temperature is about 105 °C. In some embodiments, the first temperature is about 110 °C. In some embodiments, the first temperature is about 115 °C. In some embodiments, the first temperature is about 120 °C. In some embodiments, the first temperature is about 125 °C. In some embodiments, the first temperature is about 130 °C.

[0048] In some embodiments, the first temperature is at least about 20 °C. In some embodiments, the first temperature is at least about 25 °C. In some embodiments, the first temperature is at least about 30 °C. In some embodiments, the first temperature is at least about 40 °C. In some embodiments, the first temperature is at least about 50 °C. In some embodiments, the first temperature is at least about 90 °C. In some embodiments, the first temperature is at least about 100 °C.

[0054]

[0049] In some embodiments, the second temperature is about 20 °C. In some embodiments, the second temperature is about 25 °C. In some embodiments, the second temperature is about 30 °C. In some embodiments, the second temperature is about 35 °C. In some embodiments, the second temperature is about 40 °C. In some embodiments, the second temperature is about 45 °C. In some embodiments, the second temperature is about 50 °C. In some embodiments, the second temperature is about 55 °C. In some embodiments, the second temperature is about 60 °C. In some embodiments, the second temperature is about 65 °C. In some embodiments, the second temperature is about 70 °C. In some embodiments, the second temperature is about 75 °C. In some embodiments, the second temperature is about 80 °C. In some embodiments, the second temperature is about 85 °C. In some embodiments, the second temperature is about 90 °C. In some embodiments, the second temperature is about 95 °C. In some embodiments, the second temperature is about 100 °C. In some embodiments, the second temperature is about 105 °C. In some embodiments, the second temperature is about 110 °C. In some embodiments, the second temperature is about 115 °C. In some embodiments, the second temperature is about 120 °C. In some embodiments, the second temperature is about 125 °C. In some embodiments, the second temperature is about 130 °C.

[0055]

[0050] In some embodiments, the second temperature is at least about 20 °C. In some embodiments, the second temperature is at least about 25 °C. In some embodiments, the second temperature is at least about 30 °C. In some embodiments, the second temperature is at least about 40 °C. In some embodiments, the second temperature is at least about 50 °C. In some embodiments, the second temperature is at least about 90 °C. In some embodiments, the second temperature is at least about 100 °C.

[0056]

[0051] In some embodiments, the first period of time is about 1 hour to about 4 hours. In some embodiments, the first period of time is about 1 hour to about 2 hours. In some embodiments, the first period of time is about 1 hour. In some embodiments, the first period of time is about 2 hours. In some embodiments, the first period of time is at least about 1 hour.

[0057]

[0052] In some embodiments, the second period of time is about 10 hours to about 20 hours. In some embodiments, the second period of time is about 14 hours. In some embodiments, the second period of time is at least about 14 hours.

[0053] In some embodiments, the second period of time is about 48 hours. In some embodiments, the second period of time is less than about 48 hours.

[0058]

[0054] In some embodiments, the first temperature is about 30 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 40 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 50 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 600and the first period of time is about 1 hour. In some embodiments, the first temperature is about 70 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 80 °C and the first period of time is about 1 hour.

[0059]

[0055] In some embodiments, the second temperature is about 20 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 25 °C and the second period of time is about 14 hours. In some embodiments, of the second temperature is about 30 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 40 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 50 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 60 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 70 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 80 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 90 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 100 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 110 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 120 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 130 °C and the second period of time is about 14 hours.

[0060]

[0056] In some embodiments, the method further comprises heating the aluminum or alloy thereof and / or heating the activating metal alloy separately from the mixture prior to contacting the aluminum or alloy thereof with the activating metal alloy.

[0061]

[0057] In some embodiments, the aluminum or alloy thereof is contacted with the activating metal alloy in the interior of an activation container that is sealed prior to heating the mixture or while heating the mixture. In certain embodiments, the interior of the activation container is purged with inert gas after the activation container is sealed.

[0062]

[0058] In some embodiments, the method further comprises agitating the mixture during the first period of time. In some embodiments, the mixture is static during the second period of time.

[0059] In some embodiments, the activating metal alloy comprises gallium and / or indium.

[0063]

[0060] In some embodiments, the activating metal alloy is a eutectic mixture of gallium and indium (e.g., 80% gallium, 20% indium).

[0064]

[0061] In some embodiments, the activating metal alloy is a non-eutectic mixture of gallium and indium.

[0065]

[0062] In some embodiments, the activating metal alloy is a non-eutectic alloy comprising bismuth, tin, indium, and gallium.

[0066]

[0063] In some embodiments, the activating metal alloy comprises bismuth, tin, and indium and does not comprise gallium.

[0067]

[0064] In some embodiments, the activating metal alloy is greater than or equal to about 25% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 30% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 35% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 40% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 45% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 55% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 55% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 60% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 65% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 70% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 75% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 80% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 85% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 90% indium by mass. In some embodiments, the activating metal alloy is greater than or equal to about 95% indium by mass.

[0068]

[0065] In some embodiments, the activating metal alloy is about 75% gallium by mass and about 25% indium by mass. In some embodiments, the activating metal alloy is about 70% gallium by mass and about 30% indium by mass. In some embodiments, the activating metal alloy is about 65% gallium by mass and about 35% indium by mass. In some embodiments, the activating metal alloy is about 60% gallium by mass and about 40% indium by mass. In some embodiments, the activating metal alloy is about 55% gallium by mass and about 45% indium by mass. In some embodiments, the activating metal alloy is about 50% gallium by mass and about 50% indium by mass. In some embodiments, the activating metal alloy is about 45% gallium by mass and about 55% indium by mass. In some embodiments, the activating metal alloy is about 40% gallium by mass and about 60% indium by mass. In some embodiments, the activating metal alloy is about 35% gallium by mass and about 65% indium by mass. In some embodiments, the activating metal alloy is about 30% gallium by mass and about 70% indium by mass. In some embodiments, the activating metal alloy is about 25% gallium by mass and about 75% indium by mass. In some embodiments, the activating metal alloy is about 20% gallium by mass and about 80% indium by mass. In some embodiments, the activating metal alloy is about 15% gallium by mass and about 85% indium by mass. In some embodiments, the activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the activating metal alloy is about 5% gallium by mass and about 95% indium by mass.

[0069]

[0066] In some embodiments, the activating metal alloy is about 67% gallium by mass and about 33% indium by mass.

[0070]

[0067] In some embodiments, the water-reactive aluminum composition comprises about 3% to about 6% of the activating metal alloy by mass.

[0071]

[0068] In some embodiments, the water-reactive aluminum composition comprises about 3% to about 4% of the activating metal alloy by mass.

[0072]

[0069] In some embodiments, the water-reactive aluminum composition comprises about 4% to about 5% of the activating metal alloy by mass.

[0073]

[0070] In some embodiments, the water-reactive aluminum composition comprises about 5% to about 6% of the activating metal alloy by mass.

[0074]

[0071] In some embodiments, the water-reactive aluminum composition comprises about 5% of the activating metal alloy by mass.

[0075]

[0072] In some embodiments, the activating metal alloy is a virgin alloy.

[0076]

[0073] In some embodiments, the aluminum or alloy thereof is recrystallized.

[0077]

[0074] In another aspect, provided herein is a method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with a first activating metal alloy comprising gallium to provide a first mixture; contacting the first mixture with an activating metal or a second activating metal alloy having a lower gallium content than the first mixture to provide a water-reactive aluminum composition having the activating metal alloys disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs.

[0075] In some embodiments, the method generates an activated aluminum composition having increased reactivity to water compared to an aluminum composition activated by only one activating metal alloy.

[0078]

[0076] In some embodiments, the first activating metal alloy comprises gallium and indium.

[0077] In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, about 67% gallium and about 33% indium by mass, about 50% gallium and about 50% indium by mass, about 33% gallium and about 67% indium by mass, or about 20% gallium and about 80% indium by mass.

[0079]

[0078] In some embodiments, the activating metal or second activating metal alloy is about 67% gallium and about 33% indium by mass, about 50% gallium and about 50% indium by mass, about 33% gallium and about 67% indium by mass, about 20% gallium and about 80% indium by mass, about 10% gallium and about 90% indium by mass, about 5% gallium and about 95% indium by mass, or about 100% indium by mass.

[0080]

[0079] In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass. In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass. In some embodiments, the first activating metal alloy is about 33% gallium and about 67% indium by mass. In some embodiments, the first activating metal alloy is about 20% gallium and about 80% indium by mass. In some embodiments, the first activating metal alloy is about 75% gallium and about 25% indium by mass. In some embodiments, the first activating metal alloy is about 90% gallium and about 10% indium by mass. In some embodiments, the first activating metal alloy is about 95% gallium and about 5% indium by mass.

[0081]

[0080] In some embodiments, the first activating metal is about 70% to about 80% gallium and about 20% to about 30% indium, and second activating metal alloy is about 50% to about 70% gallium and about 30% to about 50% indium.

[0082]

[0081] In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 67% gallium by mass and about 33% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 50% gallium by mass and about 50% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 33% gallium by mass and about 67% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 20% gallium by mass and about 80% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 5% gallium by mass and about 95% indium by mass. In some embodiments, the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 100% indium by mass.

[0083]

[0082] In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 50% gallium by mass and about 50% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 33% gallium by mass and about 67% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 20% gallium by mass and about 80% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 5% gallium by mass and about 95% indium by mass. In some embodiments, the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 100% indium by mass.

[0084]

[0083] In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass, and the activating metal or second activating metal alloy is about 33% gallium by mass and about 67% indium by mass. In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass, and the activating metal or second activating metal alloy is about 20% gallium by mass and about 80% indium by mass. In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass, and the activating metal or second activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass, and the activating metal or second activating metal alloy is about 5% gallium by mass and about 95% indium by mass. In some embodiments, the first activating metal alloy is about 50% gallium and about 50% indium by mass, and the activating metal or second activating metal alloy is about 100% indium by mass.

[0084] In some embodiments, the first activating metal alloy is about 33% gallium and about 67% indium by mass, and the activating metal or second activating metal alloy is about 20% gallium by mass and about 80% indium by mass. In some embodiments, the first activating metal alloy is about 33% gallium and about 67% indium by mass, and the activating metal or second activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the first activating metal alloy is about 33% gallium and about 67% indium by mass, and the activating metal or second activating metal alloy is about 5% gallium by mass and about 95% indium by mass. In some embodiments, the first activating metal alloy is about 33% gallium and about 67% indium by mass, and the activating metal or second activating metal alloy is about 100% indium by mass.

[0085]

[0085] In some embodiments, the first activating metal alloy is about 20% gallium and about 80% indium by mass, and the activating metal or second activating metal alloy is about 10% gallium by mass and about 90% indium by mass. In some embodiments, the first activating metal alloy is about 20% gallium and about 80% indium by mass, and the activating metal or second activating metal alloy is about 5% gallium by mass and about 95% indium by mass. In some embodiments, the first activating metal alloy is about 20% gallium and about 80% indium by mass, and the activating metal or second activating metal alloy is about 100% indium by mass.

[0086]

[0086] In some embodiments, the method further comprising heating each of the first mixture and / or the second mixture at a first temperature for a first period of time, and heating each of the first mixture and / or the second mixture at a second temperature for a second period of time less than about 24 hours and subsequent to the first period of time to generate a water-reactive aluminum composition having peak reactivity. In some embodiments, the method further comprises heating each of the first mixture and / or the second mixture at a first temperature for a first period of time, and heating each of the first mixture and / or the second mixture at a second temperature for a second period of time less than about 72 hours and subsequent to the first period of time to generate a water-reactive aluminum composition having peak reactivity.

[0087]

[0087] In some embodiments, the first temperature is about 125 °C to about 135 °C. In some embodiments, the first temperature is about 85 °C to about 95 °C. In some embodiments, the first temperature is about 40 °C to about 60 °C. In some embodiments, the first temperature is about 20 °C to about 30 °C. In some embodiments, the second temperature is about 40 °C to about 90 °C. In some embodiments, the second temperature is about 40 °C to about 60 °C. In some embodiments, the second temperature is about 25 °C to about 35 °C. In some embodiments, the second temperature is about 20 °C to about 30 °C. In some embodiments, the first temperature is the same as the second temperature. In some embodiments, the first temperature is higher than the second temperature. In some embodiments, the first temperature is lower than the second temperature.

[0088]

[0088] In some embodiments, the first temperature is about 20 °C. In some embodiments, the first temperature is about 25 °C. In some embodiments, the first temperature is about 30 °C. In some embodiments, the first temperature is about 35 °C. In some embodiments, the first temperature is about 40 °C. In some embodiments, the first temperature is about 45 °C. In some embodiments, the first temperature is about 50 °C. In some embodiments, the first temperature is about 55 °C. In some embodiments, the first temperature is about 60 °C. In some embodiments, the first temperature is about 65 °C. In some embodiments, the first temperature is about 70 °C. In some embodiments, the first temperature is about 75 °C. In some embodiments, the first temperature is about 80 °C. In some embodiments, the first temperature is about 85 °C. In some embodiments, the first temperature is about 90 °C. In some embodiments, the first temperature is about 95 °C. In some embodiments, the first temperature is about 100 °C. In some embodiments, the first temperature is about 105 °C. In some embodiments, the first temperature is about 110 °C. In some embodiments, the first temperature is about 115 °C. In some embodiments, the first temperature is about 120 °C. In some embodiments, the first temperature is about 125 °C. In some embodiments, the first temperature is about 130 °C.

[0089]

[0089] In some embodiments, the first temperature is at least about 20 °C. In some embodiments, the first temperature is at least about 25 °C. In some embodiments, the first temperature is at least about 30 °C. In some embodiments, the first temperature is at least about 40 °C. In some embodiments, the first temperature is at least about 50 °C. In some embodiments, the first temperature is at least about 90 °C. In some embodiments, the first temperature is at least about 100 °C.

[0090]

[0090] In some embodiments, the second temperature is about 20 °C. In some embodiments, the second temperature is about 25 °C. In some embodiments, the second temperature is about 30 °C. In some embodiments, the second temperature is about 35 °C. In some embodiments, the second temperature is about 40 °C. In some embodiments, the second temperature is about 45 °C. In some embodiments, the second temperature is about 50 °C. In some embodiments, the second temperature is about 55 °C. In some embodiments, the second temperature is about 60 °C. In some embodiments, the second temperature is about 65 °C. In some embodiments, the second temperature is about 70 °C. In some embodiments, the second temperature is about 75 °C. In some embodiments, the second temperature is about 80 °C. In some embodiments, the second temperature is about 85 °C. In some embodiments, the second temperature is about 90 °C. In some embodiments, the second temperature is about 95 °C. In some embodiments, the second temperature is about 100 °C. In some embodiments, the second temperature is about 105 °C. In some embodiments, the second temperature is about 110 °C. In some embodiments, the second temperature is about 115 °C. In some embodiments, the second temperature is about 120 °C. In some embodiments, the second temperature is about 125 °C. In some embodiments, the second temperature is about 130 °C.

[0091]

[0091] In some embodiments, the second temperature is at least about 20 °C. In some embodiments, the second temperature is at least about 25 °C. In some embodiments, the second temperature is at least about 30 °C. In some embodiments, the second temperature is at least about 40 °C. In some embodiments, the second temperature is at least about 50 °C. In some embodiments, the second temperature is at least about 90 °C. In some embodiments, the second temperature is at least about 100 °C.

[0092]

[0092] In some embodiments, the first period of time is about 1 hour to about 4 hours. In some embodiments, the first period of time is about 1 hour to about 2 hours. In some embodiments, the first period of time is about 1 hour. In some embodiments, the first period of time is about 2 hours. In some embodiments, the first period of time is at least about 1 hour.

[0093]

[0093] In some embodiments, the second period of time is about 10 hours to about 20 hours. In some embodiments, the second period of time is about 14 hours. In some embodiments, the second period of time is at least about 14 hours.

[0094]

[0094] In some embodiments, the second period of time is about 48 hours. In some embodiments, the second period of time is less than about 48 hours.

[0095]

[0095] In some embodiments, the first temperature is about 30 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 40 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 50 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 600and the first period of time is about 1 hour. In some embodiments, the first temperature is about 70 °C and the first period of time is about 1 hour. In some embodiments, the first temperature is about 80 °C and the first period of time is about 1 hour.

[0096]

[0096] In some embodiments, the second temperature is about 20 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 25 °C and the second period of time is about 14 hours. In some embodiments, of the second temperature is about 30 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 40 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 50 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 60 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 70 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 80 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 90 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 100 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 110 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 120 °C and the second period of time is about 14 hours. In some embodiments, the second temperature is about 130 °C and the second period of time is about 14 hours.

[0097]

[0097] In some embodiments, the method further comprises agitating the second mixture during heating.

[0098]

[0098] In some embodiments of the methods described herein, the aluminum or alloy thereof is scrap aluminum. In some embodiments, the aluminum or alloy thereof comprises at least one of shredded aluminum cans, aluminum foils, aluminum pellets, and aluminum sheet panels. In some embodiments, the aluminum or alloy thereof comprises more than one of shredded aluminum cans, aluminum foils, aluminum pellets, and aluminum sheet panels. In certain embodiments, the aluminum or alloy thereof comprises aluminum foils. In certain embodiments, the aluminum or alloy thereof comprises shredded aluminum cans. In certain embodiments, the aluminum or alloy thereof comprises aluminum foils or shredded aluminum cans.

[0099]

[0099] In another aspect, provided herein is a method of activating aluminum or an alloy thereof, the method comprising contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a water- reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, and wherein the aluminum or alloy thereof comprises aluminum foils.

[0100]

[0100] In some embodiments, the aluminum or alloy thereof further comprises other forms of aluminum (e.g., shredded aluminum cans, aluminum pellets, and / or aluminum sheet panels).

[0101]

[0101] In some embodiments, the aluminum or alloy thereof is recrystallized.

[0102]

[0102] In some embodiments of the methods disclosed herein, the activating metal alloy is 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% of the total mass of the water-reactive aluminum composition. In some embodiments, the activating metal alloy is 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%, about 20%, about 30%, about 40%, or about 50% of the total mass of the water-reactive aluminum composition produced by the method.

[0103]

[0103] 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 an average 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 an average diameter of about 5 mm to about 20 mm. In some embodiments, the pellets have an average diameter of about 70 mm.

[0104]

[0104] In some embodiments of the methods described herein, the activating metal alloy was recovered from a mixture comprising products of a reaction of an activated aluminum composition with water prior to contacting the aluminum or alloy thereof. In some embodiments, the activating aluminum alloy contains no water-reactive dissolved species, such as dissolved aluminum. In some embodiments, the activating aluminum alloy contains water- reactive dissolved species, such as dissolved aluminum.

[0105]

[0105] In some embodiments of the methods described herein, the activating metal alloy is a mixture of virgin activating metal alloy and an activating metal alloy recovered from a mixture comprising products of a reaction of an activated aluminum composition with water prior to contacting the aluminum or alloy thereof.

[0106]

[0106] In some embodiments of the methods described herein, the activating metal alloy(s) are liquid at room temperature.

[0107]

[0107] In some embodiments of the methods described herein, the activating metal alloy(s) are solid at room temperature.

[0108]

[0108] In some embodiments of the methods described herein, the activating metal alloy(s) are heated above their melting points within an appropriate vessel, such as a glass jar or steel container, which is sealed and purged with an inert gas, such as argon, nitrogen, helium, neon, or xenon.

[0109]

[0109] In some embodiments of the methods described herein, the activating metal alloy(s) are heated to a temperature between 20 °C to 200 °C, 25 °C to 200 °C, or 50 °C to 200 °C prior to contacting the aluminum or alloy thereof.

[0110]

[0110] In some embodiments of the methods described herein, the activating metal alloy(s) are heated for about 30 minutes to about 90 minutes prior to contacting the aluminum or alloy thereof.

[0111] In some embodiments of the methods described herein, the aluminum feedstock(s) are heated in parallel to the activating metal alloy(s) to temperatures between 20 °C to 200 °C, 25 °C to 200 °C, or 50 °C to 200 °C within an appropriate vessel, such as a glass jar or steel container, which is sealed purged with an inert gas, such as argon, nitrogen, helium, neon, xenon. In some embodiments, the vessel is not purged with an inert gas (e.g., the vessel may contain ambient air). The vessels may be sized such that only one third to one half of the interior volume of the vessel is filled with feedstock.

[0111]

[0112] In some embodiments of the methods described herein, the aluminum or alloy thereof is activated in an appropriate vessel which sealed and purged with an inert gas. In some embodiments, the inert gas is selected from argon, nitrogen, helium, neon and xenon. In some embodiments, the inert gas is argon. In some embodiments, the inert gas is nitrogen. In some embodiments, the aluminum or alloy thereof is activated in an appropriate vessel which is not purged with an inert gas. In some embodiments, the vessel contains ambient air.

[0112]

[0113] In some embodiments, the aluminum feedstock and the activating metal alloy are heated using the same heating element.

[0113]

[0114] In some embodiments, the aluminum feedstock and the activating metal alloy are heated using separate heating elements.

[0114]

[0115] The heating of the activating metal alloy can be achieved with the use of a hot plate or an oven.

[0115]

[0116] If the feedstock contains contaminants that off-gas at or below the desired temperature, the container may be left open initially to allow these gasses to escape.

[0116]

[0117] In an exemplary embodiment, once both the feedstock and the metal alloy catalyst are pre-heated for a set amount of time, an appropriate weight amount of catalyst is dispensed into the feedstock vessel. The amount of catalyst may vary anywhere from 3 to 50 wt% of the combined material depending on the selected metal alloy for the catalyst and the composition and / or microstructure structure of the feedstock. The final weight may include the weight of contaminants. The vessel may be filled with an inert gas before being sealed or the container may contain ambient air.

[0117]

[0118] With the catalyst and feedstock combined and sealed under ambient or inert conditions, the vessel may then be heated and agitated for a set amount of time. Agitation may be achieved by both manual shaking of the vessel and automated tumbling. Manual shaking may be performed at periodic intervals (e.g., every 20 to 30 minutes), taking care to shake the vessel in a way that allows the materials to be well mixed but not shaking so vigorously that the embrittled feedstock breaks apart. Manual shaking of the vessel may be performed in various spatial orientations to ensure homogenous mixing. The vessel may be reheated after each instance of shaking. The mixing may achieve even coating of the aluminum feedstock with the catalyst.

[0118]

[0119] Optionally, in either the same vessel or a new vessel, which may be sealed and filled with inert gas, the activated fuel may be heated at slightly elevated temperatures in a low temperature oven for a set amount of time to speed up the diffusion of catalyst into the bulk of the particle, decreasing the time required to reach peak reactivity. This process is also known as “curing.”

[0119] EXAMPLES

[0120] EXAMPLE 1: Preparation of activated pure aluminum with the use of primary galliumindium

[0121]

[0001] In the experiments described below, power output, energy output, and yield are calculated by measuring the flow of hydrogen released during the reaction. Energy released as hydrogen from the reaction of aluminum with water is extrapolated from the hydrogen flow using the known higher heating value (HHV) combustion energy of hydrogen. Energy released as heat / steam from the reaction of aluminum with water is extrapolated from the hydrogen flow using the fixed ratio of hydrogen (51.2%) and heat (48.8%) released during the reaction of aluminum with water (see Reaction 1 and Reaction 2).

[0122] Sample A

[0123]

[0120] Gallium-indium alloy (50-80% gallium, 20-50% indium) is preheated at 200 °C for 30 minutes in a sealed glass jar purged with argon gas. In parallel, pure aluminum feedstock (e.g., 100 g to 1000 g) in the form of 6 mm diameter spherical pellets is heated at 130 °C for 30 minutes in a steel can. The steel can is sized such that at least half of the interior volume is empty (e.g., a steel can having an interior volume of one quart). The steel can containing the aluminum is purged with argon and sealed before heating.

[0124]

[0121] After both the feedstock and the gallium-indium alloy are preheated, gallium-indium alloy is dispensed into the steel can containing the feedstock in a weight ratio of, e.g., about 4- 6.5 parts, or about 2-10 parts gallium-indium alloy per 100 parts feedstock. Both the catalyst glass jar and steel can containing the combined feedstock and catalyst are purged with argon and re-sealed.

[0125]

[0122] The steel can is agitated for 60 minutes at 50 °C such that the aluminum-catalyst mixture is thoroughly mixed.

[0126]

[0123] After this 60 minute period of activation, the mixed material is weighed to determine the final weight percent of catalyst, as some catalyst may be lost to the walls of the steel can. The final gallium-indium alloy weight percent typically falls between 4.5 and 5.1 wt% of the total weight of the mixed material. The aluminum in this mixed material is expected to be reactive and react readily with an oxidant (e.g., water). This activated mixture is considered “fuel” and may be stored in a sealed container filled with inert gas (e.g., argon). Peak reactivity is reached through additional “curing” to allow further diffusion of the catalyst through the microstructure of the feedstock. This is accomplished by allowing the fuel to sit at room temperature for 24 to 48 hours. This curing process is expedited by allowing the fuel to sit in a low temperature oven for 14 hours at 50 °C. After this 14 hour mark, the fuel is expected to reach peak reactivity similar to, if not better than, fuel cured at room temperature.

[0127] Samples B, C, D, and E

[0128]

[0124] Additional activated aluminum samples are prepared using the same general procedure as Sample A but with modifications to the time and temperature parameters for certain steps. Each sample is prepared with, e.g., 3-6 wt% or 1-9 wt% gallium-indium alloy. Exemplary process modifications are shown in Table 1.

[0129] Table 1: Process parameters for preparation of exemplary activated aluminum samples t = time, T = temperature

[0130]

[0125] Samples A, C, and E are expected to produce hydrogen flow and power output comparable to / greater than that of activated aluminum samples prepared using standard procedures (e.g., curing at room temperature for 72 hours).

[0131] EXAMPLE 2: Preparation of activated pure aluminum with the use of secondary, recovered gallium-indium alloy

[0132] Sample J

[0133]

[0126] The same general procedure described for Sample B in Example 1 is used to prepare another sample of activated fuel with pure aluminum 6mm spherical pellets and gallium-indium alloy, but instead of utilizing virgin gallium-indium alloy, gallium-indium alloy recovered from previous aluminum-water reactions is used. When gallium-indium alloy is recovered directly after activated aluminum fuel has been reacted, the gallium-indium alloy may contain dissolved species, such as dissolved aluminum, which are reactive in the presence of oxidizing species like water and oxygen. For this reason, the dissolved aluminum in the recovered catalyst used for the preparation of Sample J is first allowed to completely react in deionized water. The recovered catalyst is stored in a container filled with deionized water. The water is replaced with fresh deionized water approximately daily to remove suspended solids and dissolved ions formed by the reactive dissolved aluminum. Once there is no more evidence of hydrogen evolution in the form of small bubbles, the catalyst is removed from the container of water and allowed to dry. The gallium-indium alloy catalyst is dried by first wicking any visible droplets of water with an absorbent, lint-free wipe and then heating the gallium-indium alloy catalyst at 130 °C in a glass or metal container. The container may be open to atmosphere to allow water vapor to escape and optionally blanketed with an inert gas (e.g., argon). After 10-30 minutes of heating, the catalyst is used for activating aluminum (e.g., using the methods described in Example 1).

[0134]

[0127] Aluminum fuel activated with Sample J is expected to have reactivity and the potential for gallium-indium alloy recovery post-reaction that are indistinguishable from those of Sample B.

[0135] Samples K and L

[0136]

[0128] Sample K: After recovering the gallium-indium alloy catalyst from an aluminum-water reaction immediately upon completion of the reaction, instead of allowing the catalyst to react in water as with Sample J, the catalyst is dried in a reactive state. For this drying process, the catalyst is first dried by wicking any visible droplets of water with an absorbent, lint-free wipe. After this, the catalyst is allowed to sit in a container within a fume hood to encourage room temperature evaporation of any additional moisture under forced air flow for 10-30 minutes. The catalyst is then mixed at ambient temperature with 6mm spherical primary aluminum pellets in a container, with a target of, e.g., 3-6% or 1-9% catalyst by mass in the fuel, assuming 20-30% of the collected catalyst weight is due to dissolved and entrained (non-catalyst) species.

[0137]

[0129] Sample L: Using a procedure similar to Sample K, another sample is prepared with catalyst recovered from an aluminum-water reaction, but instead of drying and mixing the catalyst and fuel at ambient temperatures, the catalyst and the aluminum feedstock are preheated in an oven set to 50 °C. The aluminum feedstock and the catalyst are then combined in a container, with a target of, e.g., 3-6% or 1-9% catalyst by mass in the aluminum fuel, assuming 20-30% of the collected catalyst weight is due to dissolved and entrained (non-catalyst) species.

[0138]

[0130] For both Samples K and L, the aluminum is then activated (e.g., using the methods described in Example 1). Upon reaction with water, activated Samples K and L are expected to have a reaction yield of greater than 70% EXAMPLE 3: Preparation of activated scrap aluminum waste

[0139]

[0131] In this example, pure or non-pure waste aluminum is used to prepare activated aluminum fuel. “Waste” refers to any material that has served its intended purpose or a material that is a byproduct of a fabrication process such as machining scraps or dross. Non-pure waste aluminum can refer to materials with alloying components or with other separate materials and contaminants like plastic coatings, oil, food scraps, and other metallic or inorganic materials.

[0140] Scrap aluminum may be in the form of, for example, foils, machine shavings, food packaging, or dross, and may comprise thick oxide layers and / or contaminants (e.g., paper, plastic, food remnants, etc.).

[0141]

[0132] Activation of the scrap aluminum may be achieved by first shredding the scrap aluminum to a size of roughly 4-5 mm in width and around 25-35 mm in length, and packing the shreds into pellets having a diameter of, e.g., 20 mm and / or weighing about 1.5 g each. The pellets are then activated with enough gallium-indium alloy to amount to about 5-40 wt% of the activated aluminum fuel, with the activation comprising preheating the pellets and catalyst (e.g., to about 50-200 °C), combining the pellets in a container backfilled with inert gas, and agitating the pellets for a predetermined period of time (e.g., about 1-3 hours) at elevated temperatures (e.g., about 50-100 °C). The activated fuel is then allowed to cure for a predetermined period of time (e.g., 48-72 hours) at room temperature or elevated temperature (e.g., 50 °C).

[0142]

[0133] Reactivity results are expected to depend on the feedstock used, with foils expected to react to completion faster than bulk material and with materials highly contaminated with non- metallic aluminum species expected to result in lower energy density than pure metallic aluminum due to the inclusion of non-aluminum mass. The various activated feedstocks encompassed by this example are expected to achieve significant power and energy output, with average powers expected to reach 160 W per fuel pellet and a specific energy around 2.4 kWh / kg for highly contaminated feedstock and average powers expected to reach 675 W per fuel pellet and a specific energy around 8.6 kWh / kg for foils.

[0143] EXAMPLE 4: Preparation of pure aluminum with the use of primary gallium-indium with the use of nitrogen gas during initial activation step

[0144] Sample R

[0145]

[0134] Another sample of activated fuel is prepared using 6mm spherical pellets of pure aluminum and, e.g., about 3-6 wt% or 1-9 wt% gallium-indium alloy using similar process conditions as used to prepare Sample D. However, after combining the catalyst with the feedstock, the container with the combined material is filled with nitrogen gas before sealing and agitating the container. The resulting reactivity is expected to be indistinguishable with that of Sample D where argon gas is used to inert the container before mixing. EXAMPLE 5: Preparation of activated pure aluminum with the use of primary galliumindium

[0146]

[0135] In the experiments described below, power output, energy output, and yield are calculated by measuring the flow of hydrogen released during the reaction. Energy released as hydrogen from the reaction of aluminum with water is extrapolated from the hydrogen flow using the known higher heating value (HHV) combustion energy of hydrogen. Energy released as heat / steam from the reaction of aluminum with water is extrapolated from the hydrogen flow using the fixed ratio of hydrogen (51.2%) and heat (48.8%) released during the reaction of aluminum with water (see Reaction 1 and Reaction 2).

[0147] Sample S and T

[0148]

[0136] Gallium-indium alloy (67% gallium, 33% indium) was preheated at 200 °C for 30 minutes in a sealed glass jar purged with argon gas. In parallel, 100g of pure aluminum feedstock in the form of 6 mm diameter spherical pellets was heated at 130 °C for 30 minutes in a steel can. At least half of the interior volume was empty (e.g., a steel can having an interior volume of 4 fl oz). The steel can containing the aluminum was purged with argon and sealed before heating.

[0149]

[0137] After both the feedstock and the gallium-indium alloy were preheated, gallium-indium alloy was dispensed into the steel can containing the feedstock in a weight ratio of about 5 parts gallium-indium alloy per 95 parts feedstock. The steel can containing the combined feedstock and catalyst was purged with argon and re-sealed.

[0150]

[0138] The steel can was agitated for 60 minutes at 50 °C such that the aluminum-catalyst mixture was thoroughly mixed.

[0151]

[0139] After this 60 minute period of activation, the mixed material was weighed to determine the final weight percent of catalyst, as some catalyst may have been lost to the walls of the steel can. The final gallium-indium alloy weight percent was 4.29 wt% of the total weight of the mixed material. This activated mixture was stored in a sealed container filled with inert argon gas. Peak reactivity was reached through additional “curing” to allow further diffusion of the catalyst through the microstructure of the feedstock. Sample S was cured at room temperature, while Sample T was cured at 50 °C. After 17 hours, each sample was tested for reactivity, as shown for Sample T in Figure 7. The reaction yield and average reaction power for each sample is shown in Figures 10 and 11. At 17 hours, Sample T shows a higher reaction yield and reaction power.

[0152] EXAMPLE 6: Preparation of activated pure aluminum with the use of secondary, recovered gallium-indium alloy Sample U

[0153]

[0140] The same general procedure described for Sample T in Example 5 was used to prepare another sample of activated fuel with about 10 g of pure aluminum 6 mm spherical pellets and between 5-6 parts Gallium-indium alloy (67% gallium, 33% indium) per 95 parts feedstock, but instead of utilizing virgin alloy, activating alloy recovered from previous aluminum- water reactions was used. The catalyst was recovered from a reaction of fuel from Sample T 24 hours after the start of the reaction. When the activating catalyst alloy was recovered, the catalyst contained dissolved species, such as dissolved aluminum, which were reactive in the presence of water. For this reason, the dissolved aluminum in the recovered catalyst used for the preparation of Sample T was first allowed to completely react in deionized water. The recovered catalyst was stored in a container filled with deionized water. Mild heat was applied to this solution to ensure the catalyst is liquid and allows the dissolved aluminum to fully react. The solution was also gently stirred to prevent the build up of ions or solids that are produced in the reaction of the dissolved aluminum in the catalyst. Once there was no more evidence of hydrogen evolution in the form of small bubbles, the catalyst was removed from the container of water and allowed to dry. The activating alloy was dried by first wicking any visible droplets of water with an absorbent, lint-free wipe and then heating the alloy at 130 °C in a metal container. The container was purged with argon which is heavier than air and therefore the container was left open to atmosphere with a lid placed loosely on top to allow water vapor to escape. After 30 minutes of heating, the catalyst was used for activating aluminum (e.g., using the methods described in Example 5). The final weight percent catalyst was 5.5 wt% of the total fuel.

[0154]

[0141] Aluminum fuel from Sample U was reactive and indistinguishable from those of Sample T, as shown in Figure 7 and 8.

[0155] Sample V

[0156]

[0142] Sample V: After recovering the gallium-indium alloy catalyst from an aluminum-water reaction using fuel from Sample T 24 hours after the reaction start, instead of allowing the catalyst to react in water as with Sample U, the catalyst was dried in a reactive state. Sample V was activated similarly to Sample T. Because some of the catalyst alloy contains aluminum, the weight percent of recovered and reactive catalyst was around 6. 12 wt% of the fuel, assuming 20- 30% of the collected catalyst weight is due to dissolved and entrained (non-catalyst) species. The final weight percent of recovered and reactive catalyst was 4.12 wt% of the total fuel.

[0157]

[0143] Aluminum fuel from Sample V was reactive and indistinguishable from those of Sample T, as shown in Figure 7 and 9. EXAMPLE 7: Preparation of pure aluminum with the use of primary gallium-indium with the use of alternative atmospheres during initial activation step

[0158] Sample X and Sample Y

[0159]

[0144] Two more samples of activated fuel were prepared using 6 mm spherical pellets of pure aluminum and gallium-indium alloy with the chemistry of 67 wt% gallium and 33 wt% indium. The same process steps and conditions used to prepare Sample D were used to prepare Sample X and Y. However, for Sample X after combining the catalyst with the feedstock, the container with the combined material was filled with nitrogen gas before sealing and agitating the container. For Sample Y, the ambient air was not displaced by any gas.

[0160]

[0145] The resulting reactivity is indistinguishable with that of Sample D where argon gas is used to inert the container before mixing, as shown in Figure 12 (Sample X, activated in nitrogen) and Figure 13 (Sample Y, activated in ambient air).

[0161] EQUIVALENTS AND SCOPE

[0162]

[0146] In the claims articles such as "a," "an," and "the" may mean one or more than one unless indicated to the contrary or otherwise evident from the context. Claims or descriptions that 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.

[0163]

[0147] 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.

[0164]

[0148] 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 the exclusion 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.

[0165]

[0149] 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.

[0166]

[0150] 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

CLAIMSWHAT IS CLAIMED:

1. A method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 24 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the method generates a water-reactive aluminum composition having peak reactivity.

2. A method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a mixture, heating the mixture at a first temperature for a first period of time, and heating the mixture at a second temperature for a second period of time less than about 72 hours and subsequent to the first period of time to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, wherein the aluminum or alloy thereof is scrap aluminum, wherein the scrap aluminum has been shredded to form scrap aluminum shreds, and wherein the scrap aluminum shreds have been compressed into scrap aluminum pellets prior to contacting the aluminum or alloy thereof with the activating metal alloy, wherein the method generates a water-reactive aluminum composition having peak reactivity.

3. The method of claim 2, wherein the scrap aluminum pellets have an average diameter of about 20 mm.

4. The method of claim 2 or 3, wherein the scrap aluminum pellets have an average weight of about 1.5 g per pellet.

5. The method of any one of claims 1-4, wherein the first temperature is about 125 °C to about 135 °C.

6. The method of any one of claims 1-4, wherein the first temperature is about 85 °C to about 95 °C.

7. The method of any one of claims 1-4, wherein the first temperature is about 40 °C to about 60 °C.

8. The method of any one of claims 1-4, wherein the first temperature is about 20 °C to about 30 °C.

9. The method of any one of claims 1-8, wherein the second temperature is about 40 °C to about 90 °C.

10. The method of any one of claims 1-8, wherein the second temperature is about 40 °C to about 60 °C.

11. The method of any one of claims 1-8, wherein the second temperature is about 25 °C to about 35 °C.

12. The method of any one of claims 1-8, wherein the second temperature is about 20 °C to about 30 °C.

13. The method of any one of claims 1 -12, wherein the first temperature is the same as the second temperature.

14. The method of any one of claims 1-12, wherein the first temperature is higher than the second temperature.

15. The method of any one of claims 1-12, wherein the first temperature is lower than the second temperature.

16. The method of any one of claims 1-15, wherein the first period of time is about 1 hour to about 2 hours.

17. The method of any one of claims 1-16, wherein the second period of time is about 10 hours to about 20 hours.

18. The method of any one of claims 1-17, wherein the second period of time is about 14 hours.

19. The method of any one of claims 2-16, wherein the second period of time is about 48 hours.

20. The method of any one of claims 1-19, further comprising heating the aluminum or alloy thereof and / or heating the activating metal alloy separately from the mixture prior to contacting the aluminum or alloy thereof with the activating metal alloy.

21. The method of any one of claims 1-20, wherein the aluminum or alloy thereof is contacted with the activating metal alloy in the interior of an activation container that is sealed prior to heating the mixture or while heating the mixture.

22. The method of any one of claims 1-21, wherein the interior of the activation container is purged with inert gas after the activation container is sealed.

23. The method of any one of claims 1-22, further comprising agitating the mixture during the first period of time.

24. The method of any one of claims 1 -22, wherein the mixture is static during the second period of time.

25. The method of any one of claims 1-24, wherein the activating metal alloy comprises gallium and / or indium.

26. The method of any one of claims 1-25, wherein the activating metal alloy is a eutectic alloy of gallium and indium.

27. The method of any one of claims 1-25, wherein the activating metal alloy is a noneutectic alloy of gallium and indium.

28. The method of any one of claims 1-25, wherein the activating metal alloy is a noneutectic alloy comprising bismuth, tin, indium, and gallium.

29. The method of any one of claims 1-25, wherein the activating metal alloy comprises bismuth, tin, and indium and does not comprise gallium.

30. The method of any one of claims 1-25 and 27-29, wherein the activating metal alloy is greater than or equal to about 30% indium by mass.

31. The method of any one of claims 1-25 and 27-29, wherein the activating metal alloy is greater than or equal to about 50% indium by mass.

32. A method of activating aluminum or an alloy thereof, the method comprising: contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with a first activating metal alloy comprising gallium to provide a first mixture; contacting the first mixture with an activating metal or a second activating metal alloy having a lower gallium content by mass than the first activating metal alloy to provide a water- reactive aluminum composition having the activating metal alloys disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs.

33. The method of claim 32, wherein the method generates an activated aluminum composition having increased reactivity to water compared to an aluminum composition activated by only one activating metal alloy.

34. The method of claim 32 or 33, wherein the first activating metal alloy comprises gallium and indium.

35. The method of any one of claims 32-34, wherein the first activating metal alloy is about 80% gallium and about 20% indium by mass, about 67% gallium and about 33% indium by mass, about 50% gallium and about 50% indium by mass, about 33% gallium and about 67% indium by mass, or about 20% gallium and about 80% indium by mass.

36. The method of any one of claims 32-35, wherein the activating metal or second activating metal alloy is about 67% gallium and about 33% indium by mass, about 50% gallium and about 50% indium by mass, about 33% gallium and about 67% indium by mass, about 20% gallium and about 80% indium by mass, about 10% gallium and about 90% indium by mass, about 5% gallium and about 95% indium by mass, or about 100% indium by mass.

37. The method of any one of claims 32-35, wherein the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 67% gallium by mass and about 33% indium by mass.

38. The method of any one of claims 32-35, wherein the first activating metal alloy is about 80% gallium and about 20% indium by mass, and the activating metal or second activating metal alloy is about 50% gallium by mass and about 50% indium by mass.

39. The method of any one of claims 32-35, wherein the first activating metal alloy is about 67% gallium and about 33% indium by mass, and the activating metal or second activating metal alloy is about 50% gallium by mass and about 50% indium by mass.

40. The method of any one of claims 32-39, further comprising heating each of the first mixture and / or the second mixture at a first temperature for a first period of time, and heating each of the first mixture and / or the second mixture at a second temperature for a second period of time less than about 24 hours and subsequent to the first period of time to generate a water- reactive aluminum composition having peak reactivity.

41. The method of any one of claims 32-39, further comprising heating each of the first mixture and / or the second mixture at a first temperature for a first period of time, and heating each of the first mixture and / or the second mixture at a second temperature for a second period of time less than about 72 hours and subsequent to the first period of time to generate a water- reactive aluminum composition having peak reactivity.

42. The method of claim 40 or 41, wherein the first temperature is about 125 °C to about 135 °C.

43. The method of claim 40 or 41, wherein the first temperature is about 85 °C to about 95 °C.

44. The method of claim 40 or 41, wherein the first temperature is about 40 °C to about 60 °C.

45. The method of claim 40 or 41, wherein the first temperature is about 20 °C to about 30 °C.

46. The method of any one of claims 40-45, wherein the second temperature is about 40 °C to about 90 °C.

47. The method of any one of claims 40-45, wherein the second temperature is about 40 °C to about 60 °C.

48. The method of any one of claims 40-45, wherein the second temperature is about 25 °C to about 35 °C.

49. The method of any one of claims 40-45, wherein the second temperature is about 20 °C to about 30 °C.

50. The method of any one of claims 40-49, wherein the first temperature is the same as the second temperature.51 . The method of any one of claims 40-49, wherein the first temperature is higher than the second temperature.

52. The method of any one of claims 40-49, wherein the first temperature is lower than the second temperature.

53. The method of any one of claims 40-52, wherein the first period of time is about 1 hour to about 2 hours.

54. The method of any one of claims 40-53, wherein the second period of time is about 10 hours to about 20 hours.

55. The method of any one of claims 40-54, wherein the second period of time is about 14 hours.

56. The method of any one of claims 40-53, wherein the second period of time is about 48 hours.

57. The method of any one of claims 1-56, wherein the aluminum or alloy thereof is scrap aluminum.

58. The method of any one of claims 1-56, wherein the aluminum or alloy thereof comprises at least one of shredded aluminum cans, aluminum foils, aluminum pellets, and aluminum sheet panels.

59. The method of any one of claims 1-56, wherein the aluminum or alloy thereof comprises more than one of one of shredded aluminum cans, aluminum foils, aluminum pellets, and aluminum sheet panels.

60. The method of any one of claims 1-56, wherein the aluminum or alloy thereof comprises aluminum foils.

61. A method of activating aluminum or an alloy thereof, the method comprising contacting aluminum or an alloy thereof having a surface oxide layer, an interior volume, and a microstructure with an activating metal alloy to provide a water-reactive aluminum composition having the activating metal alloy disposed along the microstructure of the aluminum or the alloy thereof, wherein when water is introduced to the composition, the aluminum or alloy thereof disintegrates to expose the interior volume to the water, and a rapid hydrolysis reaction occurs, and wherein the aluminum or alloy thereof comprises aluminum foils.

62. The method of claim 61, wherein the aluminum or alloy thereof further comprises other forms of aluminum (e.g., shredded aluminum cans, aluminum pellets, and / or aluminum sheet panels).

63. The method of claim 61 or 62, wherein the activating metal alloy was recovered from a mixture comprising products of a reaction of an activated aluminum composition with water prior to contacting the aluminum or alloy thereof.

64. The method of any one of claims 1-63, wherein the aluminum or alloy thereof is recrystallized.

65. The method of any one of claims 1-64, wherein the aluminum or alloy thereof is activated in an appropriate vessel which is sealed and purged with an inert gas.

66. The method of claim 65, wherein the inert gas is argon.

67. The method of claim 65, wherein the inert gas is nitrogen.

68. The method of any one of claims 1-64, wherein the aluminum or alloy thereof is activated in an appropriate vessel which is not purged with an inert gas.

69. The method of claim 68, wherein the vessel contains ambient air.

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