Method for preparing nanometer aluminum oxide by deeply processing product obtained after aluminum-based hydrogen production

Abstract

The invention relates to the technical field of chemical material preparation, and discloses a method for preparing nanometer aluminum oxide through deep processing of aluminum-based hydrogen production products, and the method comprises the following steps: S1, raw material pretreatment; s2, acid leaching and impurity removal; s3, alkali dissolution reaction; s4, seed crystal preparation; s5, carrying out a crystallization reaction; and S6, calcining treatment to obtain a nano aluminum oxide product, in the step of acid leaching impurity removal, if the impurity content in the raw materials is high, the concentration of a nitric acid solution can be properly increased to 30-35%, the reaction time is prolonged to 3-4 hours, in the step of crystallization reaction, the reaction temperature can be controlled to be 60-65 DEG C, the pressure can be controlled to be 0.2-0.25 MPa, and the reaction time can be prolonged to 3-4 hours according to actual requirements. The method is used for preparing nanometer aluminum oxide products with different crystal forms and particle sizes. In the acid leaching impurity removal step, impurities in the product after hydrogen production are effectively removed, the purity of the raw materials is improved, conditions are strictly controlled in the seed crystal preparation and crystallization reaction process, the generated aluminum hydroxide precipitate is uniform in particle size, and a foundation is laid for subsequent preparation of high-quality nanometer aluminum oxide.

Description

Technical Field

[0001] The present invention relates to the technical field of chemical material preparation, and particularly relates to a method for deep processing the post-aluminum-based hydrogen production product into nano-aluminum oxide. Background Art

[0002] With the increasing global demand for clean energy, hydrogen energy, as an efficient and clean energy, has attracted much attention. The hydrolysis of aluminum-based materials to produce hydrogen has become one of the most promising hydrogen production technologies due to its advantages such as large hydrogen production capacity and rich raw materials. During the aluminum-based hydrogen production process, a large amount of by-products are generated, mainly aluminum hydroxide. If these by-products can be reasonably utilized, it can not only reduce resource waste but also lower the hydrogen production cost, which is in line with the concept of sustainable development. Deep processing the post-aluminum-based hydrogen production product into nano-aluminum oxide has important application value, and nano-aluminum oxide has a wide range of applications in many fields such as ceramics, electronics, and catalysts.

[0003] Currently, there are some related patents on the recycling and utilization of the hydrolysis products of aluminum-based materials for hydrogen production. For example, Patent CN111575487A discloses a method for recycling the hydrolysis products of aluminum-based materials for hydrogen production. This method involves mixing and reacting the hydrolysis products of aluminum-based materials for hydrogen production with acidic substances, separating the solid and liquid to collect the insoluble substances, and then recycling low-melting-point metals. At the same time, the by-products aluminum sulfate and aluminum hydroxide also have corresponding applications. However, the focus of this patent is on the recycling of low-melting-point metals and the utilization of by-products, and there is no detailed description on further deep processing the post-hydrogen production product into nano-aluminum oxide. Moreover, the purity and particle size of the obtained aluminum hydroxide are difficult to meet the high-quality requirements for the preparation of nano-aluminum oxide, which limits the application of the post-hydrogen production product in high-value-added fields.

[0004] Therefore, it is of great practical significance to develop a method that can efficiently and high-quality deep process the post-aluminum-based hydrogen production product into nano-aluminum oxide. This can not only expand the industrial chain of the aluminum-based hydrogen production industry, improve the comprehensive utilization rate of resources, but also meet the increasing market demand for nano-aluminum oxide, and enhance the economic benefits and competitiveness of related industries. Summary of the Invention

[0005] The purpose of the present invention is to propose a method for deep processing the post-aluminum-based hydrogen production product into nano-aluminum oxide in order to solve the above problems.

[0006] In order to achieve the above purpose, the present invention adopts the following technical solutions:

[0007] A method for deep processing the post-aluminum-based hydrogen production product into nano-aluminum oxide, comprising the following steps:

[0008] Raw material pretreatment: The product after aluminum-based hydrogen production is initially crushed to 100-200 mesh, washed multiple times with deionized water. Each time, the mass ratio of the product to deionized water is 1:5, and the washing time is 30-40 minutes. After filtration, it is dried in an oven at 80-100 °C for 8-10 hours;

[0009] Acid leaching for impurity removal: The pretreated raw material is added to a nitric acid solution with a mass fraction of 20-30%. The solid-liquid ratio of the raw material to the nitric acid solution is 1:8-1:10 (g / mL). Stir and react at 60-80 °C for 2-3 hours. After the reaction, centrifuge for separation. The centrifuge speed is 3000-4000 r / min, and the separation time is 15-20 minutes. The filter residue is washed with deionized water 2-3 times, and the water consumption for each wash is 3-5 times the mass of the filter residue;

[0010] Alkali dissolution reaction: The aluminum hydroxide after preliminary impurity removal is added to a sodium hydroxide solution with a mass fraction of 15-20%. The solid-liquid ratio of aluminum hydroxide to the sodium hydroxide solution is 1:6-1:8 (g / mL). React at 90-110 °C for 3-4 hours. During the reaction, the stirring speed is 200-300 r / min. After the reaction, cool to room temperature and filter;

[0011] Seed preparation: Take a small amount of the sodium aluminate solution obtained from the alkali dissolution reaction, slowly add dilute sulfuric acid with a mass fraction of 10-15% to it, adjust the pH value of the solution to 9-10, and the dropping speed is 2-3 drops / second. During the dropping process, the stirring speed is 150-200 r / min. After dropping, let it stand at 30-40 °C for 12-15 hours;

[0012] Crystallization reaction: Add the sodium aluminate solution obtained from the alkali dissolution reaction to the reaction kettle, add seeds, and the addition amount of seeds is 0.5-1% of the mass of the sodium aluminate solution. Introduce carbon dioxide gas into the reaction kettle, control the reaction temperature at 60-70 °C, the reaction pressure at 0.2-0.3 MPa, and the reaction time at 4-6 hours. After the reaction, filter, wash the precipitate with deionized water 3-4 times, and the water consumption for each wash is 5-8 times the mass of the precipitate. After washing, dry it in an oven at 80-100 °C for 10-12 hours;

[0013] Calcination treatment: Put the dried aluminum hydroxide precipitate into a muffle furnace, heat it up to 1000-1200 °C at a heating rate of 5-10 °C / min, calcine for 2-3 hours, and naturally cool to room temperature to obtain nano-aluminum oxide products.

[0014] Preferably, the product after aluminum-based hydrogen production comes from Henan Zhongqing Power Research Institute Co., Ltd., and the content of aluminum hydroxide is not less than 90%.

[0015] Preferably, the nitric acid solution is of analytical pure grade and is purchased from Hangzhou Fuyang Rongchang Chemical Auxiliary Factory.

[0016] Preferably, the sodium hydroxide solution is of chemically pure grade and is purchased from Hebei Xinmengmiao Chemical Technology Co., Ltd.

[0017] Preferably, the dilute sulfuric acid is of analytically pure grade and is purchased from Yangzhou Huafu Chemical Co., Ltd.

[0018] Preferably, the purity of the carbon dioxide gas is not less than 99.9% and is purchased from Jiangxi Huada Gas Co., Ltd.

[0019] Preferably, in the acid leaching and impurity removal step, if the impurity content in the raw material is relatively high, the concentration of the nitric acid solution can be appropriately increased to 30-35% and the reaction time can be extended to 3-4 hours.

[0020] Preferably, in the crystallization reaction step, according to actual needs, the reaction temperature can be controlled at 60-65°C and the pressure can be controlled at 0.2-0.25 MPa to prepare nano-aluminum oxide products with different crystal forms and particle sizes.

[0021] In summary, due to the adoption of the above technical solutions, the beneficial effects of the present invention are as follows:

[0022] 1. The nano-aluminum oxide prepared by the present invention has the characteristics of high purity and uniform particle size. In the acid leaching and impurity removal step, impurities in the product after hydrogen production are effectively removed, improving the purity of the raw material; the conditions in the seed preparation and crystallization reaction processes are strictly controlled, making the particle size of the generated aluminum hydroxide precipitate uniform, laying a foundation for the subsequent preparation of high-quality nano-aluminum oxide; the calcination treatment further ensures the crystal form and purity of the nano-aluminum oxide. The method of the present invention not only solves the problem of difficult high-quality preparation of nano-aluminum oxide in the prior art, but also improves the resource utilization rate, reduces the production cost, and has significant economic and environmental benefits. Specific Embodiments

[0023] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the embodiments of the present invention. Obviously, the described embodiments are only a part of the embodiments of the present invention, rather than all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative efforts shall fall within the protection scope of the present invention.

[0024] Example 1

[0025] Raw material pretreatment: Take 100 g of the aluminum-based product after hydrogen production from [Henan Zhongqing Power Research Institute Co., Ltd.], and perform preliminary crushing to about 150 mesh. Wash it 3 times with deionized water, add 500 g of deionized water each time, filter after washing for 35 minutes. Dry the filter residue in an oven at 90°C for 9 hours to obtain the pretreated raw material.

[0026] Acid leaching for impurity removal: The pretreated raw materials are added to 800 mL of nitric acid solution with a mass fraction of 25%, and stirred and reacted at a temperature of 70 °C for 2.5 hours. After the reaction, centrifugal separation is carried out at a rotation speed of 3500 r / min for 18 minutes, the filtrate is discarded, the filter residue is washed 3 times with deionized water, with 300 g of water used each time, and then filtered again to obtain aluminum hydroxide after preliminary impurity removal.

[0027] Alkaline dissolution reaction: The aluminum hydroxide after preliminary impurity removal is added to 600 mL of sodium hydroxide solution with a mass fraction of 18%, and stirred and reacted at a temperature of 100 °C for 3.5 hours. After the reaction, it is cooled to room temperature, and filtered to obtain a clear sodium aluminate solution.

[0028] Seed preparation: Take 50 mL of the sodium aluminate solution obtained in step 3, slowly dropwise add dilute sulfuric acid with a mass fraction of 12% thereto, adjust the pH value to 9.5, with a dropping rate of 2 - 3 drops / second, and stir at a speed of 180 r / min simultaneously. After the dropping is completed, it is left standing at a temperature of 35 °C for 13 hours to form nano aluminum hydroxide seeds.

[0029] Crystallization reaction: The sodium aluminate solution obtained in step 3 is added to a reaction kettle, and 5 g of the nano aluminum hydroxide seeds prepared in step 4 are added. Carbon dioxide gas is introduced into the reaction kettle, the reaction temperature is controlled at 65 °C, the pressure is 0.25 MPa, and the reaction is carried out for 5 hours. After the reaction, it is filtered, the precipitate is washed 4 times with deionized water, with 500 g of water used each time, and after washing, it is dried in an oven at 90 °C for 11 hours.

[0030] Calcination treatment: The dried aluminum hydroxide precipitate is put into a muffle furnace, heated to 1100 °C at a heating rate of 8 °C / min, calcined for 2.5 hours, and naturally cooled to room temperature to obtain nano aluminum oxide products.

[0031] Example 2

[0032] Basically the same as Example 1, the differences are as follows:

[0033] Acid leaching for impurity removal: The mass fraction of the nitric acid solution is 20%, the solid-liquid ratio of the raw materials to the nitric acid solution is 1:8, the reaction temperature is 60 °C, and the reaction time is 3 hours.

[0034] Alkaline dissolution reaction: The mass fraction of the sodium hydroxide solution is 15%, the solid-liquid ratio of the aluminum hydroxide to the sodium hydroxide solution is 1:6, the reaction temperature is 90 °C, and the reaction time is 4 hours.

[0035] Seed preparation: The mass fraction of the dilute sulfuric acid is 10%, the pH value is adjusted to 9, the standing temperature is 30 °C, and the standing time is 15 hours.

[0036] Crystallization reaction: The amount of seed crystals added is 0.5% of the mass of the sodium aluminate solution, the reaction temperature is 60 °C, the pressure is 0.2 MPa, and the reaction time is 6 hours.

[0037] Calcination treatment: The calcination temperature is 1000 °C and the calcination time is 3 hours.

[0038] Example 3

[0039] It is basically the same as Example 1, except that:

[0040] Acid leaching for impurity removal: The mass fraction of the nitric acid solution is 30%, the solid-liquid ratio of the raw material to the nitric acid solution is 1:10, the reaction temperature is 80 °C, and the reaction time is 2 hours.

[0041] Alkali dissolution reaction: The mass fraction of the sodium hydroxide solution is 20%, the solid-liquid ratio of aluminum hydroxide to the sodium hydroxide solution is 1:8, the reaction temperature is 110 °C, and the reaction time is 3 hours.

[0042] Seed crystal preparation: The mass fraction of the dilute sulfuric acid is 15%, the pH value is adjusted to 10, the static temperature is 40 °C, and the static time is 12 hours.

[0043] Crystallization reaction: The amount of seed crystals added is 1% of the mass of the sodium aluminate solution, the reaction temperature is 70 °C, the pressure is 0.3 MPa, and the reaction time is 4 hours.

[0044] Calcination treatment: The calcination temperature is 1200 °C and the calcination time is 2 hours.

[0045] Comparative Example 1

[0046] It is basically the same as Example 1, except that the acid leaching for impurity removal step is omitted and the alkali dissolution reaction is carried out directly.

[0047] Comparative Example 2

[0048] It is basically the same as Example 1, except that ordinary aluminum hydroxide (seed crystals prepared by methods other than the method of the present invention) is used for the crystallization reaction.

[0049] Performance test

[0050] Purity test: The purity of the nano-aluminum oxide products prepared in Examples 1-3 and Comparative Examples 1-2 was detected using an inductively coupled plasma optical emission spectrometer (ICP-OES). During the detection, the sample was dissolved with an appropriate amount of acid, diluted to a suitable concentration, and then injected into the ICP-OES instrument for analysis. The results showed that the purity of the nano-aluminum oxide prepared in Examples 1-3 all reached over 99.5%. Among them, the purity of Example 1 was 99.83%, the purity of Example 2 was 99.72%, and the purity of Example 3 was 99.99%. For Comparative Example 1, since no acid leaching was carried out for impurity removal, the product purity was only 98.25%; for Comparative Example 2, ordinary aluminum hydroxide seeds were used, and the purity was 99.06%. Thus, it can be seen that the acid leaching impurity removal step and the seeds prepared by the present invention play an important role in improving the purity of nano-aluminum oxide.

[0051] Particle size test: The particle size of the nano-aluminum oxide products was tested using a dynamic light scattering particle size analyzer. During the test, the sample was dispersed in an appropriate amount of deionized water, and after ultrasonic dispersion for 15-20 minutes, the measurement was carried out. The particle size of the nano-aluminum oxide prepared in Examples 1-3 was distributed between 30-50 nm, and the particle size was uniform. Among them, the average particle size of Example 1 was 40 nm, the average particle size of Example 2 was 42 nm, and the average particle size of Example 3 was 38 nm. The particle size distribution of the product of Comparative Example 1 was relatively wide, between 50-100 nm, and the average particle size was 70 nm; the particle size of the product of Comparative Example 2 was between 40-80 nm, and the average particle size was 60 nm. This indicates that the method of the present invention can effectively control the particle size of nano-aluminum oxide to make it more uniform.

[0052] Through the analysis of the performance test results of the examples and comparative examples, it can be seen that the present invention can prepare nano-aluminum oxide with high purity and uniform particle size by means of acid leaching impurity removal, preparation of specific seeds, and strict control of the process parameters of each reaction step, effectively solving the problems existing in the prior art, and having prominent substantial features and significant progress.

[0053] In the description of the specification, the description referring to terms such as "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in a suitable manner in any one or more embodiments or examples.

[0054] The above content is only an example and illustration of the present invention. Those skilled in the art of the present technology make various modifications or supplements to the described specific embodiments or use similar ways to replace them. As long as they do not deviate from the invention or exceed the scope defined by the claims of the present invention, they should all fall within the protection scope of the present invention.

Claims

1. A method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide, characterized in that, It includes the following steps: S1: Initially crush the product after aluminum-based hydrogen production to 100 - 200 mesh, wash it with deionized water multiple times. The mass ratio of the product to deionized water during each washing is 1:5, the washing time is 30 - 40 minutes. After filtration, dry it in an oven at 80 - 100 °C for 8 - 10 hours; S2: Add the pretreated raw material into a nitric acid solution with a mass fraction of 20 - 30%. The solid-liquid ratio of the raw material to the nitric acid solution is 1:8 - 1:10 (g / mL). Stir and react at 60 - 80 °C for 2 - 3 hours. After the reaction ends, perform centrifugal separation. The centrifuge speed is 3000 - 4000 r / min, and the separation time is 15 - 20 minutes. Wash the filter residue with deionized water 2 - 3 times, and the water consumption for each washing is 3 - 5 times the mass of the filter residue; S3: Add the preliminarily impurity-removed aluminum hydroxide into a sodium hydroxide solution with a mass fraction of 15 - 20%. The solid-liquid ratio of aluminum hydroxide to the sodium hydroxide solution is 1:6 - 1:8 (g / mL). React at 90 - 110 °C for 3 - 4 hours. The stirring speed during the reaction process is 200 - 300 r / min. After the reaction ends, cool it to room temperature and filter; S4: Take a small amount of the sodium aluminate solution obtained from the alkali dissolution reaction, slowly drip a dilute sulfuric acid with a mass fraction of 10 - 15% into it, adjust the pH value of the solution to 9 - 10, the dripping speed is 2 - 3 drops / second, and the stirring speed during the dripping process is 150 - 200 r / min. After dripping, let it stand at 30 - 40 °C for 12 - 15 hours; S5: Add the sodium aluminate solution obtained from the alkali dissolution reaction into a reaction kettle, add crystal seeds, and the addition amount of crystal seeds is 0.5 - 1% of the mass of the sodium aluminate solution. Introduce carbon dioxide gas into the reaction kettle, control the reaction temperature at 60 - 70 °C, the reaction pressure is 0.2 - 0.3 MPa, and the reaction time is 4 - 6 hours. After the reaction ends, filter, wash the precipitate with deionized water 3 - 4 times, and the water consumption for each washing is 5 - 8 times the mass of the precipitate. After washing, dry it in an oven at 80 - 100 °C for 10 - 12 hours; S6: Put the dried aluminum hydroxide precipitate into a muffle furnace, heat it up to 1000 - 1200 °C at a heating rate of 5 - 10 °C / min, calcine for 2 - 3 hours, and naturally cool to room temperature to obtain the nano-aluminum oxide product.

2. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, The content of aluminum hydroxide in the product after aluminum-based hydrogen production is not less than 90%.

3. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, The nitric acid solution is of analytical pure grade.

4. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, The sodium hydroxide solution is of chemically pure grade.

5. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, The dilute sulfuric acid is of analytical pure grade.

6. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, The purity of the carbon dioxide gas is not less than 99.9%.

7. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, In the acid leaching and impurity removal step, if the impurity content in the raw material is relatively high, the concentration of the nitric acid solution can be appropriately increased to 30 - 35%, and the reaction time can be extended to 3 - 4 hours.

8. The method for deep processing of the post-hydrogen production product of aluminum-based hydrogen production into nano-aluminum oxide according to claim 1, characterized in that, In the crystallization reaction step, according to actual needs, the reaction temperature can be controlled at 60 - 65 °C, and the pressure can be controlled at 0.2 - 0.25 MPa to prepare nano-aluminum oxide products with different crystal forms and particle sizes.