Aluminum circulation method for metal aluminum energy storage and hydrogen production

Abstract

The invention relates to an aluminum circulation method for metal aluminum energy storage and hydrogen production, and belongs to the technical field of aluminum material production. The method comprises the steps that aluminum oxide is fed into an electrolytic aluminum factory for electrolysis, and metal aluminum liquid is obtained; the metal aluminum liquid is processed, and the aluminum-based hydrogen production material with the large specific surface area is obtained; the method comprises the following steps: carrying out chemical reaction on an aluminum-based hydrogen production material and water under the action of a nitrogen-containing strong alkaline organic matter catalyst to obtain hydrogen and alumina hydrate slurry; performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing the catalyst; roasting the alumina hydrate to obtain high-activity metallurgical-grade alumina; the high-activity metallurgical-grade aluminum oxide is cyclically used for preparing metal aluminum liquid through electrolysis, and the aqueous solution containing the catalyst is cyclically used for hydrogen production through reaction of the aluminum-based hydrogen production material and water, so that a closed-loop cycle is formed. The defects of high energy consumption, high carbon emission intensity, high cost and the like in the metal aluminum preparation and aluminum recycling process are overcome.

Description

Technical Field

[0001] The present application relates to the field of new energy application technology, and in particular to an aluminum circulation method for metal aluminum energy storage and hydrogen production. Background Art

[0002] At present, the new energy technology routes based on metal aluminum energy storage mainly include aluminum-air batteries and aluminum-based hydrogen production materials-water hydrogen production. Although aluminum-air batteries have outstanding advantages such as high specific energy density and environmental friendliness, they also have defects such as low specific power density, which affects their large-scale commercial use. The aluminum-based hydrogen production material-water hydrogen production technology fully utilizes the unique advantages of metal aluminum's high energy density and hydrogen fuel cells' high electrical energy conversion efficiency, strong power adjustability, environmental friendliness, and short hydrogen refueling time, and has good development prospects.

[0003] However, current research on aluminum-based hydrogen production materials-water hydrogen production technology has only proposed the idea of ​​recycling aluminum elements after aluminum-based hydrogen production materials-water hydrogen production, and has not yet formed a practical and feasible technical route. Summary of the invention

[0004] The present application provides an aluminum circulation method for metal aluminum energy storage and hydrogen production to solve the following technical problems: providing a new aluminum circulation method for metal aluminum energy storage and hydrogen production.

[0005] In a first aspect, the present application provides an aluminum circulation method for metal aluminum energy storage and hydrogen production, the method comprising:

[0006] Electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0007] Processing the metallic aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area;

[0008] Under the action of a nitrogen-containing strong alkaline organic catalyst, the aluminum-based hydrogen production material is chemically reacted with water to obtain hydrogen and aluminum oxide hydrate slurry;

[0009] performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing the catalyst;

[0010] calcining the alumina hydrate to obtain high-activity metallurgical grade alumina;

[0011] The high-activity metallurgical-grade alumina is circulated for the electrolysis, and the aqueous solution containing the catalyst is circulated to participate in the chemical reaction, forming a closed-loop cycle.

[0012] Optionally, the nitrogen-containing strongly alkaline organic catalyst includes at least one of the following: diethylenetriamine, triethylenetetramine, and metformin hydroxide.

[0013] Optionally, the calcination process parameters include: a calcination temperature of 750° C. to 1020° C., and a calcination time of 3 seconds to 20 minutes.

[0014] Optionally, the process parameters of the chemical reaction include: reaction temperature of 20°C to 95°C, and reaction time of 60min to 720min.

[0015] Optionally, the mass ratio of the catalyst to the water is 1:(4-40).

[0016] Optionally, the mass ratio of the aluminum-based hydrogen-producing material to the water is 1:(4-60).

[0017] Optionally, the form of the aluminum-based hydrogen-producing material includes one of the following: aluminum particles and aluminum chips.

[0018] Optionally, the particle size D of 90% of the particles in the aluminum particles is 90 30 μm to 1000 μm; and / or,

[0019] The maximum thickness of the aluminum chips is ≤1 mm.

[0020] Optionally, the electric energy for electrolysis comes from green electric energy.

[0021] Optionally, the inert anode for electrolysis includes one of the following: a SnO2 ceramic anode and a Cu-Ni-Fe metal anode.

[0022] The above technical solution provided by the embodiment of the present application has the following advantages compared with the prior art:

[0023] The aluminum circulation method for metal aluminum energy storage and hydrogen production provided in an embodiment of the present application comprises: electrolyzing aluminum oxide to obtain metal aluminum liquid; processing the metal aluminum liquid to obtain an aluminum-based hydrogen-producing material with a large specific surface area; chemically reacting the aluminum-based hydrogen-producing material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry; performing solid-liquid separation on the aluminum oxide hydrate slurry to obtain aluminum oxide hydrate and an aqueous solution containing the catalyst; calcining the aluminum oxide hydrate to obtain high-activity metallurgical-grade aluminum oxide; circulating the high-activity metallurgical-grade aluminum oxide to participate in the electrolysis, and circulating the aqueous solution containing the catalyst to participate in the chemical reaction, to form a closed-loop cycle. Alumina is electrolyzed to obtain metallic aluminum liquid, thereby realizing the storage of electrical energy by metallic aluminum; the metallic aluminum liquid is processed to obtain an aluminum-based hydrogen-producing material with a large specific surface area, thereby increasing the contact area between the aluminum-based hydrogen-producing material and water; the aqueous solution of nitrogen-containing strongly alkaline organic matter can quickly dissolve and remove the oxide film on the surface of metallic aluminum, accelerate the chemical reaction rate of aluminum and water, and thus improve the efficiency of hydrogen production; the nitrogen-containing strongly alkaline organic catalyst has a high solubility in water and has a good dispersing effect on the aluminum oxide hydrate produced by hydrolysis, thereby more effectively exerting the catalytic effect; the aluminum oxide hydrate obtained by solid-liquid separation of the aluminum oxide hydrate slurry is roasted to obtain high-activity metallurgical-grade aluminum oxide, which has a high dissolution rate in the molten electrolyte when circulated, and is sufficient to effectively improve the current efficiency of the aluminum oxide electrolysis process; the high-activity metallurgical-grade aluminum oxide can be circulated for the above-mentioned aluminum oxide electrolysis process, and the aqueous solution containing the catalyst can be circulated to participate in the chemical reaction of the above-mentioned aluminum-based hydrogen-producing material and water, forming a closed-loop cycle. Therefore, efficient utilization of aluminum, zero solid waste emissions and near-zero carbon emissions are achieved. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] The accompanying drawings, which are incorporated in and constitute a part of this specification, illustrate embodiments consistent with the present application and, together with the description, serve to explain the principles of the present application.

[0025] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, for ordinary technicians in this field, other drawings can be obtained based on these drawings without paying any creative labor.

[0026] Figure 1 A schematic flow chart of an aluminum circulation method for metal aluminum energy storage and hydrogen production provided in an embodiment of the present application;

[0027] Figure 2 A simplified flow chart of an aluminum circulation method for metal aluminum energy storage and hydrogen production provided in an embodiment of the present application. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the embodiments of the present application clearer, the technical solution in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of this application.

[0029] Various embodiments of the present application may be presented in the form of a range; it should be understood that the description in the form of a range is only for convenience and brevity, and should not be understood as a rigid limitation on the scope of the present application; therefore, the range description should be considered to have specifically disclosed all possible sub-ranges and single numerical values ​​within the range. For example, the range description from 1 to 6 should be considered to have specifically disclosed sub-ranges, such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., as well as single numbers within the range, such as 1, 2, 3, 4, 5 and 6, which apply regardless of the range. In addition, whenever a numerical range is indicated herein, it is meant to include any cited number (fractional or integer) within the indicated range.

[0030] In the present application, in the absence of any contrary description, the directional words used, such as "upper" and "lower", are specifically the directions of the drawings in the accompanying drawings. In addition, in the description of the present specification, the terms "including", "comprising", etc. refer to "including but not limited to". In this article, relational terms such as "first" and "second" are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply that there is any such actual relationship or order between these entities or operations. In this article, "and / or" describes the association relationship of the associated objects, indicating that there may be three relationships, for example, A and / or B, which can represent: A exists alone, A and B exist at the same time, and B exists alone. Wherein A, B can be singular or plural. In this article, "at least one" refers to one or more, and "plural" refers to two or more. "At least one", "at least one of the following" or similar expressions refer to any combination of these items, including any combination of singular or plural items. For example, "at least one of a, b, or c", or "at least one of a, b, and c", can all represent: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, c can be single or multiple. In the proportional relationship involved in this article, the parameters that need to be described by proportion should be understood as the first term of the proportional formula in the order of description, and the proportional numbers should be understood as the second term of the proportional formula. For example, the mass ratio of substance A, substance B, and substance C is 1:2:3, then substance A, substance B, and substance C should correspond one-to-one with the proportional numbers in the proportional formula in the order of description, that is, the mass of substance A: the mass of substance B: the mass of substance C = 1:2:3.

[0031] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0032] In a first aspect, the present application provides an aluminum circulation method for metal aluminum energy storage and hydrogen production. Figure 1 A schematic diagram of a process flow of an aluminum circulation method for metal aluminum energy storage and hydrogen production provided in an embodiment of the present application; see Figure 1 , the method comprising:

[0033] S1, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0034] In some embodiments, the electric energy for electrolysis comes from green electric energy.

[0035] In some embodiments, the inert anode for electrolysis includes one of the following: a SnO2 ceramic anode, a Cu-Ni-Fe metal anode.

[0036] In the embodiment of the present application, aluminum oxide is first used as a raw material for electrolysis to obtain metallic aluminum liquid, and electrical energy is converted into chemical energy and stored in aluminum, thereby realizing the storage of electrical energy in metallic aluminum. During the electrolysis process, aluminum oxide is dissolved in a molten salt electrolyte such as cryolite (Na3AlF6), and is reduced to metallic aluminum at the cathode under the action of direct current, and electrical energy is converted into chemical energy and stored in metallic aluminum. The electrical energy for electrolysis can be derived from green electricity, which reduces greenhouse gas emissions such as carbon dioxide from the source, making the electrolytic aluminum production process more environmentally friendly, and green electricity can be one of wind power, solar power generation, and photovoltaic power generation. Green electricity (green electricity) such as wind power is sent to an aluminum electrolytic plant that uses inert anode technology. The aluminum oxide electrolysis process uses inert anode technology, which fundamentally solves the problem of perfluorocarbon (PFC) emissions and anode consumption and CO2 emissions. The inert anode for electrolysis can be a SnO2 ceramic anode or a Cu-Ni-Fe metal anode. During the electrolytic production of aluminum oxide using the inert anode, a small amount of metal elements such as Sn and Fe in the inert anode enters the metallic aluminum liquid to form an aluminum alloy, which is beneficial to improve the reaction activity of the hydrogen-producing material and accelerate the subsequent aluminum-based hydrogen-producing material-water hydrogen production reaction rate.

[0037] Exemplarily, S1 includes: in an aluminum electrolytic plant using wind power and applying SnO2 or Cu-Ni-Fe ceramic anode technology, alumina is first dissolved in cryolite molten salt to obtain metallic aluminum liquid through electrolysis.

[0038] S2, processing the metallic aluminum liquid to obtain an aluminum-based hydrogen production material having a large specific surface area;

[0039] In some embodiments, the aluminum-based hydrogen-producing material is in a form of: aluminum particles, aluminum chips.

[0040] In some embodiments, 90% of the aluminum particles have a particle size D 90 30 μm to 1000 μm; and / or,

[0041] The maximum thickness of the aluminum chips is ≤1 mm.

[0042] In the embodiment of the present application, the aluminum liquid is processed to obtain an aluminum-based hydrogen production material with a large specific surface area; the processing method can be an atomization method or a mechanical processing method. The aluminum-based hydrogen production material can be in the form of aluminum particles or aluminum chips. The particle size D of 90% of the particles in the aluminum particles is 90 The maximum thickness of the aluminum chips can be ≤1mm, which ensures that the aluminum-based hydrogen production material has a large specific surface area, thereby accelerating the chemical reaction rate between the aluminum-based hydrogen production material and water, and ensuring that the aluminum-based hydrogen production material can react completely with water. For example, the particle size D of 90% of the aluminum particles is 90It can be 30μm, 40μm, 50μm, 60μm, 100μm, 200μm, 300μm, 400μm, 500μm, 600μm, 700μm, 800μm, 900μm, 1000μm, etc.

[0043] S3, under the action of a nitrogen-containing strong alkaline organic catalyst, chemically reacting the aluminum-based hydrogen-producing material with water to obtain hydrogen and aluminum oxide hydrate slurry;

[0044] In some embodiments, the nitrogen-containing strongly basic organic catalyst includes at least one of the following: diethylenetriamine, triethylenetetramine, and metformin hydroxide.

[0045] In the embodiment of the present application, the aqueous solution of the nitrogen-containing strong alkaline organic catalyst can remove the oxide film on the surface of the metal aluminum, thereby accelerating the chemical reaction rate of aluminum and water, and further improving the efficiency of hydrogen production; the nitrogen-containing strong alkaline organic catalyst has a high solubility in water, which can make the catalyst evenly dispersed in water, increase the dispersibility and fluidity of the alumina hydrate slurry, and thus more effectively play a catalytic role; and under the action of the nitrogen-containing strong alkaline organic catalyst, matching the process parameters of the mild chemical reaction, efficient hydrogen production can be achieved, and the obtained alumina hydrate does not contain sodium. The nitrogen-containing strong alkaline organic catalyst can be a combination of one or more of diethylenetriamine, triethylenetetramine, and metformin hydroxide.

[0046] In some embodiments, the process parameters of the chemical reaction include: a reaction temperature of 20° C. to 95° C., and a reaction time of 60 min to 720 min.

[0047] In the embodiment of the present application, the reaction temperature of the above chemical reaction can be 20°C to 95°C, so that the reaction speed of the chemical reaction can be regulated, and the appropriate hydrogen production reaction time can be controlled according to the reaction temperature. The reaction time can be 60min to 720min, which can fully improve the utilization rate of aluminum-based hydrogen production materials. Exemplarily, the reaction temperature can be 20°C, 30°C, 40°C, 50°C, 60°C, 70°C, 80°C, 90°C, 95°C, etc.; the reaction time can be 60min, 70min, 80min, 90min, 100min, 200min, 300min, 400min, 500min, 600min, 720min, etc.

[0048] In some embodiments, the mass ratio of the catalyst to the water is 1:(4-40).

[0049] In an embodiment of the present application, the mass ratio of the catalyst to water can be 1: (4-40), which can make the concentration of the catalyst in the chemical reaction system moderate, can quickly activate the reaction at the beginning of the reaction, increase the contact opportunities between the catalyst molecules and the aluminum-based hydrogen-producing material and water, and the catalyst can provide sufficient active sites to accelerate the electron transfer process between the aluminum-based hydrogen-producing material and water. Thereby speeding up the chemical reaction rate between the aluminum-based hydrogen-producing material and water. Exemplarily, the mass ratio of the catalyst to water can be 1: 4, 1: 5, 1: 6, 1: 7, 1: 8, 1: 9, 1: 10, 1: 15, 1: 20, 1: 25, 1: 30, 1: 35, 1: 40, etc.

[0050] In some embodiments, the mass ratio of the aluminum-based hydrogen-producing material to the water is 1:(4-60).

[0051] In the embodiment of the present application, the mass ratio of the aluminum-based hydrogen-producing material to water can be 1:(4-60), which can make the concentration of the aluminum-based hydrogen-producing material in the chemical reaction system moderate, ensure the hydrogen production reaction speed, and the alumina hydrate slurry after the chemical reaction has good fluidity. Exemplarily, the mass ratio of the aluminum-based hydrogen-producing material to water can be 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, 1:45, 1:50, 1:55, 1:60, etc.

[0052] S4, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing the catalyst;

[0053] S5, calcining the alumina hydrate to obtain high-activity metallurgical grade alumina;

[0054] In some embodiments, the calcination process parameters include: a calcination temperature of 750° C. to 1020° C., and a calcination time of 3 s to 20 min.

[0055] In the embodiment of the present application, the alumina hydrate slurry is subjected to solid-liquid separation to obtain alumina hydrate and an aqueous solution containing the catalyst. Generally speaking, the alumina hydrate obtained by the chemical reaction of the above-mentioned aluminum-based hydrogen production material with water needs to be washed and dried. Alumina hydrate is roasted to obtain high-activity metallurgical grade alumina. The roasting process parameters include: the roasting temperature can be 750°C to 1020°C, and the roasting time can be 3s to 20min, which can ensure that qualified high-activity metallurgical grade alumina is obtained. The high-activity metallurgical grade alumina has excellent solubility in molten electrolyte. Exemplarily, the calcination temperature can be 750°C, 800°C, 850°C, 900°C, 950°C, 1000°C, 1020°C, etc.; the calcination time can be 3s, 4s, 5s, 6s, 7s, 8s, 20s, 30s, 1min, 2min, 3min, 4min, 5min, 6min, 7min, 8min, 9min, 10min, 12min, 14min, 15min, 17min, 19min, 20min, etc.

[0056] S6. The high-activity metallurgical-grade alumina is circulated for the electrolysis, and the aqueous solution containing the catalyst is circulated to participate in the chemical reaction, forming a closed-loop cycle.

[0057] In the embodiment of the present application, the high-activity metallurgical-grade alumina has a large specific surface area and a high reactivity, which can improve the efficiency of the electrolysis process. The high-activity metallurgical-grade alumina circulates in the electrolysis, has a high dissolution rate in the molten electrolyte, and can improve the current efficiency of the electrolysis process; the dissolution rate of the high-activity metallurgical-grade alumina in cryolite or potassium-containing cryolite molten salt is increased by more than 50% compared with the typical industrial alumina, and the current efficiency of the electrolysis process is increased by more than 2% (the dissolution rate of the typical industrial alumina is 100-200s, the current efficiency of the ordinary electrolysis process is 92-95%, and the current efficiency is less than 90% when the inert anode technology is applied). The high-activity metallurgical-grade alumina does not contain sodium, and the consumption of fluoride salts in the alumina electrolysis process can be reduced in the alumina electrolysis. The high-activity metallurgical-grade alumina can be circulated for electrolysis to prepare metallic aluminum liquid, and the above-mentioned catalyst-containing aqueous solution can be circulated for the above-mentioned aluminum-based hydrogen production material and water chemical reaction hydrogen production process. Therefore, efficient utilization of aluminum, no solid waste discharge and near-zero carbon emissions are achieved. In addition, the systems for realizing the aluminum cycle include hydrogen production systems, aluminum material recycling plants, the use of green electricity such as wind power, and aluminum electrolytic plants that apply inert anode technology.

[0058] An aluminum circulation method for metal aluminum energy storage and hydrogen production provided in the embodiment of the present application has the following advantages:

[0059] 1. Electrolyze aluminum oxide to obtain aluminum liquid (energy storage link)

[0060] Principle and significance: In the process of preparing aluminum liquid by electrolysis, electrical energy is converted into chemical energy and stored in aluminum, which makes aluminum have the potential to release energy later (hydrogen production or other applications). From the perspective of energy utilization, this energy storage method combined with green electricity (such as electricity generated by renewable energy such as wind power and solar power) can effectively solve the problem of unstable power generation process of renewable energy such as wind power and improve the stability and flexibility of energy utilization.

[0061] 2. Processing of aluminum liquid into aluminum-based hydrogen production materials

[0062] The importance of specific surface area: Aluminum-based hydrogen-producing materials with large specific surface area are processed. Large specific surface area means that more aluminum atoms can come into contact with water, thereby increasing reaction sites and accelerating the reaction rate.

[0063] 3. The role of nitrogen-containing strong alkaline organic catalysts in hydrogen production reactions

[0064] Catalytic mechanism: The aqueous solution of nitrogen-containing strong alkaline organic catalyst can quickly dissolve and remove the oxide film on the surface of aluminum metal, thereby accelerating the hydrogen production reaction. In addition, the alkaline group may promote the dissociation of water, produce more active hydroxide ions, and accelerate the hydrogen production process. Solubility advantage: The high solubility of the catalyst in water ensures its uniform dispersion, improves the dispersibility and fluidity of the alumina hydrate slurry, and thus promotes the chemical reaction.

[0065] 5. Calcination of alumina hydrate

[0066] Alumina hydrate is roasted to obtain high-activity metallurgical grade alumina. Since alumina hydrate has higher surface activity than ordinary industrial aluminum hydroxide, high-activity metallurgical grade alumina can be obtained after roasting.

[0067] 6. Recycling

[0068] Circulation of high-activity metallurgical-grade alumina: When high-activity metallurgical-grade alumina is circulated to participate in electrolysis, it has a high dissolution rate in the molten electrolyte, which is conducive to improving the electrolysis efficiency. The high activity of high-activity metallurgical-grade alumina makes the current efficiency higher during the electrolysis process, reducing energy loss and energy consumption. Circulation of aqueous solution containing catalyst: The circulation of aqueous solution containing catalyst participates in the hydrogen production chemical reaction, which reduces the consumption of catalyst and reduces the cost, and also avoids the environmental pollution problems that may be caused by catalyst discharge.

[0069] The present application will be further described below in conjunction with specific embodiments. It should be understood that these embodiments are intended only to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods for the unrecorded specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, then carry out according to general international standards, normal conditions or according to the conditions recommended by the manufacturer.

[0070] Example 1

[0071] An aluminum circulation method for aluminum metal energy storage and hydrogen production, Figure 2 A simplified flow chart of an aluminum circulation method for aluminum energy storage and hydrogen production provided in the embodiment of the present application; see Figure 2 ,include:

[0072] S11, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0073] Specifically: In an aluminum electrolytic plant that uses wind power and SnO2 ceramic anode technology, aluminum oxide is first dissolved in 945°C cryolite molten salt to obtain aluminum liquid through electrolysis;

[0074] S21, processing the aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; wherein the aluminum-based hydrogen production material is D 90 Aluminum particles with a diameter of 30 μm (90% of the particles pass through);

[0075] S31, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0076] Specifically, aluminum particles, catalyst and distilled water are added into the aluminum-water hydrogen production system in proportion, the catalyst is diethylenetriamine; the mass ratio of the catalyst to distilled water is 1:4, the mass ratio of aluminum particles to distilled water is 1:60, the chemical reaction temperature is 95°C, the reaction time is 60 minutes, and the reaction rate of aluminum particles is 98.1%;

[0077] S41, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0078] S51, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 750° C. and the roasting time is 20 min;

[0079] S61. Recycle the high-activity metallurgical-grade alumina for electrolysis in step S11, and add new water and catalyst to the aqueous solution containing the catalyst and then recycle it to participate in the chemical reaction in step S31, forming a closed-loop cycle.

[0080] The dissolution rate of the high-activity alumina in Example 1 in cryolite molten salt is increased by 56% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 2.5%.

[0081] Example 2

[0082] An aluminum circulation method for metal aluminum energy storage and hydrogen production, comprising:

[0083] S12, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0084] Specifically: In an aluminum electrolytic plant that uses wind power and SnO2 ceramic anode technology, aluminum oxide is first dissolved in 960°C cryolite molten salt to obtain aluminum liquid through electrolysis;

[0085] S22, processing the aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; wherein the aluminum-based hydrogen production material is D 90 Aluminum particles with a diameter of 1000 μm (90% of the particles pass through the particle size);

[0086] S32, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0087] Specifically, aluminum particles, catalyst and distilled water are added into the aluminum-water hydrogen production system in proportion, the catalyst is triethylenetetramine; the mass ratio of the catalyst to distilled water is 1:10, the mass ratio of aluminum particles to distilled water is 1:20, the chemical reaction temperature is 20°C, the reaction time is 720 minutes, and the reaction rate of aluminum particles is 99.6%;

[0088] S42, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0089] S52, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 1020° C. and the roasting time is 3 seconds;

[0090] S62, recycling the high-activity metallurgical-grade alumina for electrolysis in step S12, and adding new water and catalyst to the aqueous solution containing the catalyst and recycling it to participate in the chemical reaction in step S32, thereby forming a closed-loop cycle.

[0091] The dissolution rate of the high-activity alumina in Example 2 in cryolite molten salt is increased by 70% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 3.0%.

[0092] Example 3

[0093] An aluminum circulation method for metal aluminum energy storage and hydrogen production, comprising:

[0094] S13, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0095] Specifically: In an aluminum electrolytic plant that uses wind power and SnO2 ceramic anode technology, aluminum oxide is first dissolved in 950°C cryolite molten salt to obtain aluminum liquid through electrolysis;

[0096] S23, processing the metallic aluminum liquid to obtain an aluminum-based hydrogen production material having a large specific surface area; wherein the aluminum-based hydrogen production material is aluminum chips having a maximum thickness of 1 mm;

[0097] S33, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0098] Specifically, aluminum chips, catalyst and distilled water are added into the aluminum-water hydrogen production system in proportion, the catalyst is metformin hydroxide; the mass ratio of catalyst to distilled water is 1:4, the mass ratio of aluminum chips to distilled water is 1:6, the chemical reaction temperature is 65°C, the reaction time is 480 minutes, and the reaction rate of aluminum chips is 99.8%;

[0099] S43, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0100] S53, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 1000° C. and the roasting time is 10 seconds;

[0101] S63, recycling the high-activity metallurgical-grade alumina for electrolysis in step S13, and adding new water and catalyst to the aqueous solution containing the catalyst to participate in the chemical reaction in step S33, thereby forming a closed-loop cycle.

[0102] The dissolution rate of the high-activity alumina in Example 3 in cryolite molten salt is increased by 51% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 3.2%.

[0103] Example 4

[0104] An aluminum circulation method for metal aluminum energy storage and hydrogen production, comprising:

[0105] S14, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0106] Specifically, in an aluminum electrolytic plant that uses wind power and Cu-Ni-Fe metal anode technology, aluminum oxide is first dissolved in cryolite molten salt at 750°C, and aluminum liquid is obtained through electrolysis;

[0107] S24, processing the aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; wherein the aluminum-based hydrogen production material is D 90 Aluminum particles with a diameter of 80 μm (90% of the particles pass through);

[0108] S34, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0109] Specifically, aluminum particles, catalyst and distilled water are added to the aluminum-water hydrogen production system in proportion, the catalyst is a mixture of metformin hydroxide, diethylenetriamine and triethylenetetramine in a mass ratio of 1:1:1; the mass ratio of the catalyst to distilled water is 1:10, the mass ratio of aluminum particles to distilled water is 1:4, the chemical reaction temperature is 55°C, the reaction time is 540 minutes, and the reaction rate of aluminum particles is 99.3%;

[0110] S44, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0111] S54, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 750° C. and the roasting time is 20 min;

[0112] S64, recycling the high-activity metallurgical-grade alumina for electrolysis in step S14, and adding new water and catalyst to the aqueous solution containing the catalyst to participate in the chemical reaction in step S34, thereby forming a closed-loop cycle.

[0113] The dissolution rate of the high-activity alumina in Example 4 in cryolite molten salt is increased by 80% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 4.2%.

[0114] Example 5

[0115] An aluminum circulation method for metal aluminum energy storage and hydrogen production, comprising:

[0116] S15, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0117] Specifically, in an aluminum electrolytic plant that uses wind power and Cu-Ni-Fe metal anode technology, aluminum oxide is first dissolved in cryolite molten salt at 740°C, and aluminum liquid is obtained through electrolysis;

[0118] S25, processing the aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; wherein the aluminum-based hydrogen production material is D 90 Aluminum particles with a diameter of 40 μm (90% of the particles pass through);

[0119] S35, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0120] Specifically, aluminum particles, catalyst and distilled water are added to the aluminum-water hydrogen production system in proportion, the catalyst is a mixture of diethylenetriamine and triethylenetetramine in a mass ratio of 2:1; the mass ratio of the catalyst to distilled water is 1:20, the mass ratio of aluminum particles to distilled water is 1:20, the chemical reaction temperature is 85°C, the reaction time is 120 minutes, and the reaction rate of aluminum particles is 99.6%;

[0121] S45, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0122] S55, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 1000° C. and the roasting time is 3 seconds;

[0123] S65, recycling the high-activity metallurgical-grade alumina for electrolysis in step S15, and adding new water and catalyst to the aqueous solution containing the catalyst to participate in the chemical reaction in step S35, thereby forming a closed-loop cycle.

[0124] The dissolution rate of the high-activity alumina in Example 5 in cryolite molten salt is increased by 60% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 5.3%.

[0125] Example 6

[0126] An aluminum circulation method for metal aluminum energy storage and hydrogen production, comprising:

[0127] S16, electrolyzing aluminum oxide to obtain metallic aluminum liquid;

[0128] Specifically, in an aluminum electrolytic plant that uses wind power and Cu-Ni-Fe metal anode technology, aluminum oxide is first dissolved in cryolite molten salt at 760°C, and aluminum liquid is obtained through electrolysis;

[0129] S26, processing the aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; wherein the aluminum-based hydrogen production material is D 90 Aluminum particles with a diameter of 800 μm (90% of the particles pass through);

[0130] S36, chemically reacting the aluminum-based hydrogen production material with water under the action of a nitrogen-containing strong alkaline organic catalyst to obtain hydrogen and aluminum oxide hydrate slurry;

[0131] Specifically, aluminum particles, catalyst and distilled water are added to the aluminum-water hydrogen production system in proportion, the catalyst is a mixture of metformin hydroxide and triethylenetetramine in a mass ratio of 1:4; the mass ratio of the catalyst to distilled water is 1:40, the mass ratio of aluminum particles to distilled water is 1:12, the chemical reaction temperature is 95°C, the reaction time is 180 minutes, and the reaction rate of aluminum particles is 99.3%;

[0132] S46, performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing a catalyst;

[0133] S56, roasting the alumina hydrate to obtain high-activity metallurgical grade alumina; wherein the roasting temperature is 750° C. and the roasting time is 20 min;

[0134] S66, recycling the high-activity metallurgical-grade alumina for electrolysis in step S16, and adding new water and catalyst to the aqueous solution containing the catalyst and recycling it to participate in the chemical reaction in step S36, forming a closed-loop cycle.

[0135] The dissolution rate of the high-activity alumina in Example 6 in cryolite molten salt is increased by 75% compared with that of ordinary industrial alumina, and the current efficiency of the electrolysis process is increased by 6.1%, forming a closed-loop cycle.

[0136] One or more technical solutions in the embodiments of the present application also have at least the following technical effects or advantages:

[0137] (1) The dissolution rate of the high-activity metallurgical-grade alumina provided in the embodiments of the present application in cryolite or potassium-containing cryolite molten salt is increased by more than 50% compared with typical industrial alumina, and the current efficiency of the electrolysis process is increased by more than 2%;

[0138] (2) The aluminum-based hydrogen production material-water hydrogen production process in the embodiment of the present application uses nitrogen-containing strong alkaline organic matter as a catalyst, which has the advantages of fast reaction speed and no sodium element in the aluminum oxide hydrate;

[0139] (3) In the aluminum oxide electrolysis process using the inert anode in the embodiment of the present application, a small amount of metal elements such as Sn and Fe in the inert anode enters the aluminum liquid to form an aluminum alloy, which is more conducive to improving the reaction activity of the hydrogen production material and accelerating the aluminum-based hydrogen production material-water hydrogen production reaction rate;

[0140] (4) The high-activity metallurgical-grade alumina used as the raw material for alumina electrolysis in the embodiments of the present application does not contain sodium, which can reduce the consumption of fluoride salts in the production process of metallic aluminum;

[0141] (5) The alumina electrolysis process in the present application embodiment uses inert anode technology, which fundamentally solves the perfluorocarbon (PFC) emission problem;

[0142] (6) In the embodiment of the present application, the electrolysis of alumina uses high-activity metallurgical grade as raw material to produce metallic aluminum, which has the advantages of fast alumina dissolution rate and high current efficiency;

[0143] (7) The aluminum recycling method for metal aluminum energy storage and hydrogen production provided in the embodiments of the present application achieves efficient utilization of aluminum, zero solid waste emissions, and near-zero carbon emissions.

[0144] The above description is only a specific implementation of the present application, so that those skilled in the art can understand or implement the present application. Various modifications to these embodiments will be apparent to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present application. Therefore, the present application will not be limited to the embodiments shown herein, but will conform to the widest scope consistent with the principles and novel features applied for herein.

Claims

1. An aluminum circulation method for aluminum metal energy storage and hydrogen production, the method comprising: Electrolyzing aluminum oxide to obtain metallic aluminum liquid; Processing the metallic aluminum liquid to obtain an aluminum-based hydrogen production material with a large specific surface area; Under the action of a nitrogen-containing strong alkaline organic catalyst, the aluminum-based hydrogen production material is chemically reacted with water to obtain hydrogen and aluminum oxide hydrate slurry; performing solid-liquid separation on the alumina hydrate slurry to obtain alumina hydrate and an aqueous solution containing the catalyst; calcining the alumina hydrate to obtain high-activity metallurgical grade alumina; The high-activity metallurgical-grade alumina is circulated for the electrolysis, and the aqueous solution containing the catalyst is circulated to participate in the chemical reaction, forming a closed-loop cycle.

2. The method according to claim 1, characterized in that The nitrogen-containing strongly alkaline organic catalyst includes at least one of the following: diethylenetriamine, triethylenetetramine, and metformin hydroxide.

3. The method according to claim 1, characterized in that The calcination process parameters include: a calcination temperature of 750° C. to 1020° C. and a calcination time of 3 seconds to 20 minutes.

4. The method according to claim 1, characterized in that: The process parameters of the chemical reaction include: reaction temperature of 20° C. to 95° C., and reaction time of 60 min to 720 min.

5. The method according to claim 1, characterized in that The mass ratio of the catalyst to the water is 1:(4-40).

6. The method according to claim 1, characterized in that The mass ratio of the aluminum-based hydrogen production material to the water is 1:(4-60).

7. The method according to claim 1, characterized in that The aluminum-based hydrogen production material may be in the following forms: aluminum particles and aluminum chips.

8. The method according to claim 7, characterized in that The particle size D of 90% of the particles in the aluminum particles 90 30 μm to 1000 μm; and / or, The maximum thickness of the aluminum chips is ≤1 mm.

9. The method according to claim 1, characterized in that: The electric energy for the electrolysis comes from green electric energy.

10. The method according to claim 1 or 9, characterized in that: The inert anode for electrolysis includes one of the following: SnO2 ceramic anode and Cu-Ni-Fe metal anode.

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