A method for preparing boehmite based on aluminum matrix composite hydrolysis hydrogen production product

Abstract

The application discloses a method for preparing boehmite based on aluminum matrix composite hydrolysis hydrogen production. The preparation method comprises the following steps: dispersing the aluminum matrix composite hydrolysis hydrogen production into first water and adjusting the pH to 1-3, then carrying out a mixing reaction, and then carrying out solid-liquid separation, drying and grinding into powder to obtain an intermediate product; dispersing the intermediate product into second water and adjusting the pH to 8-12, then carrying out a hydrothermal reaction, and then carrying out solid-liquid separation, drying and grinding into powder to obtain boehmite. The method can remove low-melting-point metals in the aluminum matrix composite hydrolysis hydrogen production, and can also prepare boehmite with high purity; the method can realize the maximization of aluminum matrix composite utilization, reduce the cost, and make the prepared boehmite have application in the fields of ceramic materials, battery separators and flame retardants, and has important practical application value.

Description

Technical Field

[0001] This invention belongs to the field of boehmite preparation technology, and particularly relates to a method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials. Background Technology

[0002] Boehmite, also known as boehmite monohydrate or boehmite, is the main component of bauxite, with the chemical formula γ-AlOOH. It is a partially dehydrated aluminum hydroxide. Natural boehmite contains impurities, making it unsuitable for industrial applications. Synthetically synthesized boehmite possesses high purity, high heat resistance, low hardness, good insulation, and strong chemical stability, making it widely applicable in ceramic materials, coating materials, flame retardants, catalysts, and carriers. Currently, most boehmite preparation methods use inorganic or organic aluminum salts as the aluminum source through hydrothermal reactions, but these methods are extremely costly. Furthermore, the introduced ions make solvent recovery difficult. Therefore, there is an urgent need to find a novel method for synthesizing boehmite.

[0003] Hydrogen production from molten aluminum is an integrated hydrogen production and storage technology that obtains high-purity hydrogen through the direct reaction of aluminum with water. It is considered one of the most promising methods for hydrogen production. The products of aluminum hydrolysis are typically Bayerite (Al(OH)3) and low-crystallinity boehmite (AlOOH). How to recycle and reuse these byproducts is a key to effectively reducing the cost of aluminum-based composite materials and is crucial for the industrialization of hydrogen production from molten aluminum.

[0004] At room temperature, a dense oxide film forms on the surface of aluminum, making it difficult for water to contact the Al surface and thus hindering the aluminum-water reaction. Currently, the main methods for breaking down the Al surface oxide film include adding active additives, improving the solution environment, and increasing external mechanical force. Among these, adding low-melting-point metals (In, Sn, Ga, Bi, Mg, etc.) to Al to prepare aluminum-based composite materials is a common and effective way to activate Al. However, the addition of low-melting-point metals undoubtedly affects the purity of the hydrolysis products from the aluminum-water reaction. How to remove low-melting-point metals from the hydrogen production products of aluminum-based composite materials while simultaneously preparing high-purity boehmite is another key issue in the recycling of aluminum-water products. Summary of the Invention

[0005] The purpose of this invention is to overcome the above-mentioned technical deficiencies and propose a method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials, thereby solving the technical problems of low purity of hydrogen production products from the hydrolysis of aluminum-based composite materials and difficulty in preparing high-purity boehmite in the prior art.

[0006] This invention provides a method for preparing boehmite from hydrogen production products generated by hydrolysis of aluminum-based composite materials, comprising the following steps:

[0007] The hydrogen production product from the hydrolysis of aluminum-based composite materials was dispersed in a first water and the pH was adjusted to 1-3. Then, a mixing reaction was carried out, followed by solid-liquid separation, drying, and grinding into powder to obtain an intermediate product.

[0008] The intermediate product was dispersed in a second water and the pH was adjusted to 8-12. Then, a hydrothermal reaction was carried out, followed by solid-liquid separation, drying, and grinding into powder to obtain boehmite.

[0009] Compared with the prior art, the beneficial effects of the present invention include:

[0010] The method of this invention can remove low-melting-point metals from the hydrogen production products of aluminum-based composite materials through hydrolysis, and can also prepare high-purity boehmite. This method can maximize the utilization of aluminum-based composite materials and reduce costs, and also enable the prepared boehmite to have applications in ceramic materials, battery separators and flame retardants, etc., which has important practical application value. Attached Figure Description

[0011] Figure 1 These are the XRD patterns of embodiments 1 to 4 of the present invention;

[0012] Figure 2 The XRD patterns are those of Comparative Examples 1 to 9 of the present invention;

[0013] Figure 3 This is a SEM image of Embodiment 1 of the present invention;

[0014] Figure 4 This is a SEM image of Embodiment 2 of the present invention;

[0015] Figure 5 This is a SEM image of Embodiment 3 of the present invention;

[0016] Figure 6 This is a SEM image of Embodiment 4 of the present invention. Detailed Implementation

[0017] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the invention.

[0018] This invention provides a method for preparing boehmite from hydrogen production products generated by hydrolysis of aluminum-based composite materials, comprising the following steps:

[0019] S1. The hydrogen production product from the hydrolysis of aluminum-based composite material is dispersed in the first water and the pH is adjusted to 1-3. Then, a mixing reaction is carried out, followed by solid-liquid separation, drying, and grinding into powder to obtain the intermediate product.

[0020] S2. The intermediate product is dispersed in the second water and the pH is adjusted to 8-12. Then, a hydrothermal reaction is carried out, followed by solid-liquid separation, drying, and grinding into powder to obtain boehmite.

[0021] This invention utilizes a combination of acid and alkali treatment to process the hydrogen production products from the hydrolysis of aluminum-based composite materials. This process yields highly crystalline boehmite while simultaneously removing low-melting-point metals from the hydrolysis products, resulting in higher-purity boehmite. Under acidic conditions, low-melting-point metals such as In and Sn in the hydrolysis products react with the acid solution to generate In. 3+ With Sn 2+ Plasma exists in aqueous solution and can be removed during centrifugation. Furthermore, hydrogen energy is also obtained from the aluminum-water reaction. This invention not only provides a method for preparing boehmite, but also reduces the cost of hydrogen production from aluminum-water and promotes the industrialization of hydrogen production from aluminum-water.

[0022] In this embodiment, the hydrogen production product from the hydrolysis of aluminum-based composite material is obtained by separating the solid and liquid phases after the aluminum-based composite material has completely reacted with water.

[0023] Specifically, the aluminum-based composite material includes at least one of Al-In, Al-Sn, Al-In-Sn, and Al-In-Sn-NaCl.

[0024] More specifically, the Al content in the aluminum-based composite material is ≥80%, and even further ≥90%.

[0025] More specifically, the hydrogen production product from the hydrolysis of aluminum-based composite materials is obtained through the following steps: at least one of 90wt%Al-10wt%In, 90wt%Al-10wt%Sn, 90wt%Al-2wt%In-8wt%Sn, and 90wt%Al-1.5wt%In-6wt%Sn-2.5wt%NaCl is reacted with deionized water at a solid-liquid ratio of 1g:(50-1000)ml for 12-36h; the resulting solution is then separated into solid and liquid phases by vacuum filtration; subsequently, the obtained solid is dried and ground into powder to obtain the hydrogen production product from the hydrolysis of aluminum-based composite materials.

[0026] In this embodiment, the pH is adjusted to 1-3, preferably 1.5-2, by adding acid. Too high a pH will result in incomplete removal of low-melting-point metals; too low a pH will result in a decrease in product yield and crystallinity.

[0027] Specifically, the acid includes at least one of sulfuric acid and hydrochloric acid.

[0028] In this embodiment, the mass ratio of the hydrogen production product from the hydrolysis of the aluminum-based composite material to the first water is 0.5–2 g: 200 mL, and more specifically 1–2 g: 200 mL.

[0029] In this embodiment, the mixing reaction temperature is 60℃~90℃, including but not limited to 60℃, 70℃, 80℃, 90℃, etc.; the mixing reaction time is 10h~24h, including but not limited to 10h, 12h, 14h, 16h, 18h, 20h, 22h, 24h, etc.; the mixing reaction is carried out under stirring conditions. During the mixing reaction, excessively low temperature or excessively short time will lead to incomplete removal of low melting point metals; excessively high temperature or excessively long time has a positive effect on the removal of low melting point metals, but will undoubtedly lead to higher energy consumption, and will also increase the loss of products in the solution.

[0030] This invention ensures the yield of boehmite while removing low-melting-point metals by controlling the pH range, temperature, and time during the mixing reaction process.

[0031] In this embodiment, the pH is adjusted to 8-12, preferably 10-12, by adding alkali. During the hydrothermal reaction, an excessively high pH will cause the hydrolysis products to completely dissolve in the solution; a low pH or neutral conditions may result in impure boehmite (a mixed phase of boehmite and Al(OH)3) or very low crystallinity.

[0032] Specifically, the alkali includes at least one of NaOH solution or KOH solution.

[0033] In this embodiment, the mass ratio of the intermediate product to the second water is 0.3–2 g: 80 mL, and more specifically 0.8–2 g: 80 mL.

[0034] In this embodiment, the hydrothermal reaction temperature is 140℃~200℃, including but not limited to 140℃, 160℃, 180℃, 200℃, etc.; the hydrothermal reaction time is 12~30h, including but not limited to 12h, 14h, 16h, 18h, 20h, 22h, 24h, 26h, 28h, 30h, etc. Excessively high temperatures or excessively long reaction times will damage the structure and crystallinity of boehmite; excessively low temperatures or excessively short reaction times will result in low purity of the prepared boehmite, and the hydrolysis products of the aluminum-based composite material will not be completely converted into boehmite.

[0035] This invention achieves high purity and high crystallinity boehmite yield while controlling the pH range, temperature, and time during the hydrothermal reaction process.

[0036] In this invention, solid-liquid separation is performed by centrifugation or filtration.

[0037] In this invention, the dried solid is ground into powder simply by manual grinding.

[0038] To avoid redundancy, in the following examples and comparative examples, the hydrogen production product from the hydrolysis of aluminum-based composite materials was obtained through the following steps: 1 g of 90 wt% Al-1.5 wt% In-6 wt% Sn-2.5 wt% NaCl was reacted with 200 ml of deionized water at 25 °C for 24 h; the resulting solution was then separated into solid and liquid phases by vacuum filtration; subsequently, the obtained solid was placed in a forced-air drying oven and kept at 80 °C for 12 h. After drying, it was manually ground into powder to obtain the hydrogen production product from the hydrolysis of aluminum-based composite materials, denoted as solid A.

[0039] Example 1

[0040] (1) Take 0.5g of solid A and add it to 200ml of water. Adjust the pH to 1.5 with hydrochloric acid, and disperse by sonication and stirring. Then place the dispersion in an oil bath and stir for 12h at 80℃.

[0041] (2) Centrifuge the solution after reaction at 9000 rpm for 1 min, pour out the supernatant, and repeat this operation more than three times. Clean the obtained solid, and then put the solid in a forced-air drying oven to dry at 70℃ for 12 h. After drying, grind it into powder by hand and record it as solid B.

[0042] (3) The obtained solid B was placed in 80 ml of water, and the pH was adjusted to 12 with NaOH. The solution was ultrasonically and stirred to disperse it, and then poured into a polytetrafluoroethylene high-pressure reactor. The high-pressure reactor was transferred to a forced-air drying oven and hydrothermally heated at 180°C for 24 h, and then cooled to room temperature with the furnace.

[0043] (4) The cooled reaction solution is centrifuged at 9000 rpm for 1 min, and the supernatant is poured out. This operation is repeated more than three times. The obtained solid is cleaned and placed in a forced-air drying oven to dry at 70°C for 12 h. After drying, it is manually ground into powder to obtain boehmite.

[0044] Example 2

[0045] (1) Take 2g of solid A and add it to 200ml of water. Adjust the pH to 1 with hydrochloric acid, and disperse by sonication and stirring. Then place the dispersion in an oil bath and stir for 24h at 60℃.

[0046] (2) Centrifuge the solution after reaction at 9000 rpm for 1 min, pour out the supernatant, and repeat this operation more than three times. Clean the obtained solid, and then put the solid in a forced-air drying oven to dry at 70°C for 12 h. After drying, manually grind it into powder and record it as solid B.

[0047] (3) The obtained solid B was placed in 80 ml of water, and the pH was adjusted to 10 with KOH. The solution was ultrasonically and stirred to disperse it, and then poured into a polytetrafluoroethylene high-pressure reactor. The high-pressure reactor was transferred to a forced-air drying oven and hydrothermally heated at 140°C for 30 h, and then cooled to room temperature with the furnace.

[0048] (4) The cooled reaction solution is centrifuged at 9000 rpm for 1 min, and the supernatant is poured out. This operation is repeated more than three times. The obtained solid is cleaned and placed in a forced-air drying oven to dry at 70°C for 12 h. After drying, it is manually ground into powder to obtain boehmite.

[0049] Example 3

[0050] (1) Take 1g of solid A and add it to 200ml of water. Adjust the pH to 3 with sulfuric acid, and disperse by sonication and stirring. Then place the dispersion in an oil bath and stir for 10h at 90℃.

[0051] (2) Centrifuge the solution after reaction at 9000 rpm for 1 min, pour out the supernatant, and repeat this operation more than three times. Clean the obtained solid, and then put the solid in a forced-air drying oven to dry at 70℃ for 12 h. After drying, grind it into powder by hand and record it as solid B.

[0052] (3) The obtained solid B was placed in 80 ml of water, and the pH was adjusted to 9 with NaOH. The solution was ultrasonically and stirred to disperse it, and then poured into a polytetrafluoroethylene high-pressure reactor. The high-pressure reactor was transferred to a forced-air drying oven and hydrothermally heated at 200°C for 24 h, and then cooled to room temperature with the furnace.

[0053] (4) The cooled reaction solution is centrifuged at 9000 rpm for 1 min, and the supernatant is poured out. This operation is repeated more than three times. The obtained solid is cleaned and placed in a forced-air drying oven to dry at 70°C for 12 h. After drying, it is manually ground into powder to obtain boehmite.

[0054] Example 4

[0055] (1) Take 1g of solid A and add it to 200ml of water. Adjust the pH to 2 with hydrochloric acid, and disperse by sonication and stirring. Then place the dispersion in an oil bath and stir for 18h at 85℃.

[0056] (2) Centrifuge the solution after reaction at 9000 rpm for 1 min, pour out the supernatant, and repeat this operation more than three times. Clean the obtained solid, and then put the solid in a forced-air drying oven to dry at 70℃ for 12 h. After drying, grind it into powder by hand and record it as solid B.

[0057] (3) The obtained solid B was placed in 80 ml of water, and the pH was adjusted to 8 with NaOH. The solution was ultrasonically and stirred to disperse it, and then poured into a polytetrafluoroethylene high-pressure reactor. The high-pressure reactor was transferred to a forced-air drying oven and hydrothermally heated at 190°C for 12 hours, and then cooled to room temperature with the furnace.

[0058] (4) The cooled reaction solution is centrifuged at 9000 rpm for 1 min, and the supernatant is poured out. This operation is repeated more than three times. The obtained solid is cleaned and placed in a forced-air drying oven to dry at 70°C for 12 h. After drying, it is manually ground into powder to obtain boehmite.

[0059] Compare with Example 1

[0060] (1) Take 0.5g of solid A and put it in 80ml of water. Adjust the pH to 12 with NaOH. Sonicate and stir the solution to disperse it, and pour it into a polytetrafluoroethylene high-pressure reactor. Transfer the high-pressure reactor to a forced-air drying oven and hydrothermally heat it at 180℃ for 24h. Cool it to room temperature with the furnace.

[0061] (2) The cooled reaction solution is centrifuged at 9000 rpm for 1 min, and the supernatant is poured out. This operation is repeated more than three times. The obtained solid is cleaned and placed in a forced-air drying oven to dry at 70°C for 12 h. After drying, it is manually ground into powder to obtain boehmite.

[0062] Compare with Example 2

[0063] Compared with Example 1, the only difference is that the oil bath temperature is different in step (1). The oil bath temperature in this comparative example is 50°C.

[0064] Compare with Example 3

[0065] Compared with Example 1, the only difference is that the pH value is different in step (1), and the pH value of this control example is 4.

[0066] Compare with Example 4

[0067] Compared with Example 1, the only difference is that the pH value is different in step (1), and the pH value of this control example is 0.5.

[0068] Compare with Example 5

[0069] Compared with Example 3, the only difference is that the hydrothermal temperature is different in step (3). The hydrothermal temperature of this comparative example is 120°C.

[0070] Compare with Example 6

[0071] Compared with Example 3, the only difference is that the hydrothermal temperature is different in step (3). The hydrothermal temperature of this comparative example is 220°C.

[0072] Compare with Example 7

[0073] Compared with Example 3, the only difference is that the hydrothermal time in step (3) is different; the hydrothermal time in this comparative example is 8 hours.

[0074] Compare with Example 8

[0075] Compared with Example 3, the only difference is that the hydrothermal time in step (3) is different. The hydrothermal time in this comparative example is 32h.

[0076] Compare with Example 9

[0077] Compared with Example 3, the only difference is that the pH value is different in step (3), and the pH value of this control example is 7.

[0078] Compare with Example 10

[0079] Compared with Example 3, the only difference is that the pH value is different in step (3), and the pH value of this control example is 14.

[0080] Among them, Comparative Example 1 is used to compare with Example 1, mainly to distinguish between the acid-then-alkali process and the direct alkaline treatment process. Comparative Example 2 is used to compare with Example 1, mainly to illustrate the effect of excessively low water bath temperature on boehmite synthesis. In addition, Comparative Examples 3 and 4 are used to compare with Example 1, mainly to discuss the effect of acid treatment pH outside the parameter range on boehmite synthesis. Comparative Examples 5 and 6, 7 and 8, 9 and 10 are used to compare with Example 3, respectively to discuss the synthesis of boehmite when hydrothermal temperature, hydrothermal time, and hydrothermal pH value are outside the parameter range.

[0081] Please see Figures 1-2 ,pass Figure 1 and Figure 2The XRD results show that the boehmite prepared within the process range has high purity and crystallinity, and no InOOH peaks were observed. Combining Comparative Example 1 and Example 1, it is demonstrated that acidic water bath treatment of the hydrolysis product is beneficial for removing low-melting-point metals from the hydrolysis product. Meanwhile, combining Comparative Example 2, it is easy to see that when the water bath temperature is too low, InOOH is still present in the synthesized product, indicating that the removal of low-melting-point metals is incomplete. Combining Comparative Examples 3 and 4 with Example 1, at pH=4, the presence of InOOH in the product is clearly visible, further indicating the presence of low-melting-point metals in the product after acid treatment. At pH 0.5, the peak intensity of the acid treatment decreases significantly; this phenomenon is attributed to the excessive acidity causing erosion of the product's crystal faces and destroying the product's structure. Comparing Comparative Examples 5 and 6 with Example 3, it was found that the product was not completely converted into boehmite when the hydrothermal temperature was too low. When the hydrothermal temperature exceeded 200°C, the product almost completely dissolved in water. Observation of Comparative Examples 7 and 8 with Example 3 reveals that the boehmite synthesized under shorter hydrothermal times has very low crystallinity, and the crystallinity of the synthesized boehmite also decreases when the time is extended from 24 h to 32 h. Furthermore, combining Comparative Examples 9 and 10 with Example 3, it can be seen that when the hydrothermal pH is 7, the purity of the boehmite is low, and incompletely converted Al(OH)3 is still present. When the pH is 14, the product is completely soluble in water after hydrothermal treatment.

[0082] Please see Figures 3-6 ,pass Figures 3-6 As can be seen from the SEM images, the boehmite morphology prepared in Examples 1 to 4 is a rhombic blocky structure.

[0083] Table 1. Yields of boehmite prepared from hydrolysis products in each example and comparative example.

[0084]

[0085] As shown in Table 1, in Control Example 1, under direct hydrothermal treatment without acid treatment, the hydrolysis product experienced a 30.2% mass loss during the conversion to boehmite. This is because a certain amount of water needs to be removed during the conversion of Al(OH)3 to boehmite. Analysis of Example 1 shows that after acidic water bath followed by alkaline hydrothermal treatment, the mass loss was 34.6%, a 4.4% decrease compared to the treatment without acid. Furthermore, except for Example 3, the yields of the other examples were all above 60%. This phenomenon may indicate that at higher hydrothermal temperatures and longer hydrothermal times, the product converted to NaAlO2, resulting in a low boehmite yield. The parameters of the other control groups (2-10) were all outside the range of this process. Control group 3 had a yield of 69.4% at pH=4, higher than Example 1, because the synthesized product contained InOOH. In Control Example 4, the product loss was significantly increased at pH=0.5. Comparative Examples 5 and 6 illustrate the effect of hydrothermal temperature under a single variable. The yield of Comparative Example 5 was 66.4%, significantly higher than Example 3, because the hydrogen production product from the hydrolysis of the aluminum-based composite material was not completely converted to boehmite. The yield of Comparative Example 6 was almost zero because the excessively high hydrothermal temperature caused the product to convert to NaAlO2. Comparative Examples 7 and 8 illustrate the effect of hydrothermal time under a single variable. Shorter times resulted in lower crystallinity of the formed product and incomplete dehydration of the hydrolysis product, leading to an increased yield. Longer hydrothermal times resulted in a decreased yield. Comparative Examples 9 and 10 illustrate the effect of hydrothermal pH on the product under a single variable. Clearly, at pH = 7, the incomplete conversion of the hydrolysis product to boehmite led to an increased yield. However, at pH = 14, the excessive alkalinity caused the product to convert to NaAlO2 after hydrothermal treatment, resulting in an almost zero yield.

[0086] Table 2 shows the crystallinity of each embodiment and control example, calculated using the following crystallinity calculation formula:

[0087] Crystallinity = (Area of ​​crystalline peaks / Area of ​​crystalline peaks + Area of ​​amorphous peaks) * 100.

[0088] Table 2. Crystallinity of boehmite prepared from hydrolysis products of each embodiment and control example.

[0089]

[0090]

[0091] As shown in Table 2, within the range of synthesis parameters, all embodiments exhibit good crystallinity. Example 1 shows the highest crystallinity at 79.02%.

[0092] In summary, compared with the prior art, the beneficial effects of the present invention also include:

[0093] (1) The raw materials of the present invention are selected from aluminum molten metal by-products. The aluminum molten metal by-products are mainly a mixed phase of pseudoboehmite and aluminum hydroxide. Although the composition phase is similar to that of aluminum hydroxide, the product contains low melting point metal impurities (In, Sn, etc.). If the product is not purified, the reuse of the product will inevitably be limited by the purity, which reduces its reuse value. The present invention treats the aluminum molten metal by-products with acid first and then alkali. While obtaining highly crystalline boehmite, the low melting point metals in the hydrolysis product are removed, which further improves the purity of the boehmite.

[0094] (2) The present invention further defines the pH value of acid treatment. Within the scope of the present invention, residual low melting point metals in the hydrolysis products can be effectively removed. At the same time, the metal removal efficiency is improved by simply heating the solution. The acid treatment conditions of the present invention do not have a significant impact on the subsequent synthesis of boehmite and ensure a high yield of boehmite.

[0095] (3) In the alkaline hydrothermal crystallization process, the pH is controlled at 8-12, which not only provides favorable conditions for the synthesis of boehmite but also removes low-melting-point metals. Under acidic conditions, based on the relative reactivity of metals (before H), the order of reaction with acid is Al > In > Sn. The substitution reaction of Sn with H occurs last. Therefore, under alkaline conditions, Sn can react with hot caustic alkali to generate sodium stannate, further removing any residual Sn from the hydrolysis products. Simultaneously, since the solubility of sodium stannate increases with increasing temperature and can also be increased under alkaline conditions, alkaline hydrothermal treatment is also beneficial for further Sn removal. The reaction equation for the reaction of Sn with hot caustic alkali to generate sodium stannate is:

[0096] Sn+2NaOH+2H2O→Na2[Sn(OH)4]+H2.

[0097] (4) This invention uses only one acid treatment + one alkaline hydrothermal crystallization treatment and manual grinding. It does not require strict control of the size of aluminum hydroxide grains through planetary ball milling, sand milling, vibration milling or colloid milling. It can also achieve complete transformation of boehmite phase and finally obtain small-sized, flat-surfaced and uniform-shaped rhombic boehmite. Compared with the multiple hydrothermal treatments and harsh grinding conditions in the prior art, this process is simpler to operate and has lower cost and energy consumption.

[0098] The specific embodiments of the present invention described above do not constitute a limitation on the scope of protection of the present invention. Any other corresponding changes and modifications made in accordance with the technical concept of the present invention should be included within the scope of protection of the claims of the present invention.

Claims

1. A method for preparing boehmite from hydrogen production products generated by hydrolysis of aluminum-based composite materials, characterized in that, Includes the following steps: The hydrogen production products from the hydrolysis of aluminum-based composite materials were dispersed in a first water and the pH was adjusted to 1-3. Then, a mixing reaction was carried out, followed by solid-liquid separation, drying, and grinding into powder to obtain an intermediate product. The intermediate product was dispersed in a second water and the pH was adjusted to 8-12, followed by a hydrothermal reaction. After solid-liquid separation, drying, and grinding into powder, boehmite was obtained. The hydrogen production product from the hydrolysis of the aluminum-based composite material is obtained by solid-liquid separation after the aluminum-based composite material has completely reacted with water; the aluminum-based composite material includes at least one of Al-In, Al-Sn, Al-In-Sn, and Al-In-Sn-NaCl; The temperature of the mixing reaction is 60℃~90℃, and the time of the mixing reaction is 10h~24h; The hydrothermal reaction temperature is 140℃~200℃, and the hydrothermal reaction time is 12~30h.

2. The method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials according to claim 1, characterized in that, The aluminum-based composite material contains ≥80% Al.

3. The method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials according to claim 1, characterized in that, The mass ratio of the hydrogen production product from the hydrolysis of the aluminum-based composite material to the first water is 0.5~2g:200mL; the mass ratio of the intermediate product to the second water is 0.3~2g:80mL.

4. The method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials according to claim 1, characterized in that, The hydrothermal reaction temperature is 180℃~200℃, and the hydrothermal reaction time is 12~24h.

5. The method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials according to claim 1, characterized in that, The pH is adjusted to 1-3 by adding acid, wherein the acid includes at least one of sulfuric acid and hydrochloric acid; the pH is adjusted to 8-12 by adding alkali, wherein the alkali includes at least one of NaOH solution or KOH solution.

6. The method for preparing boehmite based on the hydrogen production products from the hydrolysis of aluminum-based composite materials according to claim 1, characterized in that, The dried solid is ground into powder by manual grinding.

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