Process for the preparation of boehmite

Abstract

The application relates to the technical field of inorganic material preparation, in particular to a preparation method of boehmite, which comprises the following steps: S1, placing aluminum hydroxide in a ball mill jar and performing dry grinding by using a planetary ball mill; S2, placing the aluminum hydroxide powder after ball milling in a crucible to perform first-stage heating, and the first-stage heating is from room temperature to 200 DEG C; S3, performing second-stage heating, the second-stage heating is from 200 DEG C to 300 DEG C-400 DEG C, and staying at the terminal temperature of the reaction for 0.5 h; S4, after the heating reaction is completed, cooling to room temperature, and collecting the obtained white powder; and S5, screening and removing the magnet from the collected white powder to obtain the final product boehmite. The preparation method of the boehmite is simple in synthesis process operation, high in safety, low in requirement for equipment, low in cost and excellent in economy.

Description

Technical Field

[0001] This invention relates to the field of inorganic material preparation technology, and in particular to a method for preparing boehmite. Background Technology

[0002] In recent years, the demand for high-energy-density, long-cycle-life lithium-ion batteries has increased dramatically. While increasing battery capacity, the performance requirements for battery separators are also rising to enhance battery safety. Although traditional PE separators are relatively inexpensive, they have poor heat resistance and electrolyte wettability.

[0003] Alumina is abundant in nature and possesses excellent chemical inertness, thermal stability, and mechanical properties, making it a common membrane coating material and widely used in lithium-ion battery membranes. In recent years, boehmite (AlOOH) has gradually replaced alumina as a new type of lithium-ion battery membrane coating material. Compared to alumina, boehmite has lower hardness, causing less damage to equipment and membranes during coating; it also has better heat resistance and lower energy consumption.

[0004] However, the current method for synthesizing boehmite with moderate particle size and good dispersibility mainly uses hydrothermal synthesis. Hydrothermal reaction method has certain operational risks, limited production capacity, and poor economic efficiency. Summary of the Invention

[0005] The technical problem to be solved by this invention is that the current methods for synthesizing boehmite mainly use hydrothermal methods. Hydrothermal reaction methods have certain operational risks, limited production capacity, and poor economic efficiency.

[0006] Therefore, the present invention provides a method for preparing boehmite, which has a simple synthesis process, high safety, low equipment requirements, low cost, and excellent economic efficiency.

[0007] To achieve the above objectives, the present invention provides a method for preparing boehmite, comprising the following steps:

[0008] S1, aluminum hydroxide is placed in a ball mill jar and dry-milled using a planetary ball mill;

[0009] S2, the ball-milled aluminum hydroxide powder is placed in a crucible for the first stage of heating, which is from room temperature to 150℃~280℃;

[0010] S3, the second stage of heating is carried out, from 150℃~280℃ to 300℃~400℃, and held at the reaction termination temperature for 0.5h;

[0011] S4, after the heating reaction is complete, cool to room temperature and collect the resulting white powder;

[0012] S5. The collected white powder is sieved and demagnetized to obtain the final product, boehmite.

[0013] The boehmite preparation method of the present invention is simple to operate, highly safe, requires minimal equipment, is low in cost, and is economically efficient. The phase analysis of the product synthesized by this method using X-ray diffraction (XRD) showed that the diffraction peaks mainly originated from the characteristic peaks of boehmite. Scanning electron microscopy (SEM) images showed that the synthesized boehmite had an average size of about 500 nm and was relatively uniform. Compared with existing boehmite materials obtained by hydrothermal reaction, the particle size was smaller and the uniformity was better.

[0014] Furthermore, in step S1, the ball milling speed is 400 rpm to 800 rpm; the ball milling time is 2 h to 6 h.

[0015] Furthermore, in step S1, 0.5–2 g of ball milling aid is added during the ball milling process.

[0016] Furthermore, step S1 includes the following steps:

[0017] S11. Use an electronic balance to accurately weigh 0.5-1.5 kg of aluminum hydroxide powder and 0.5-2 g of caustic soda ball milling aid, and add them to the ball mill jar;

[0018] S12, using a planetary ball mill, the ball mill jar containing aluminum hydroxide and caustic soda powder is ball milled, with the ball mill speed set to 400 rpm to 800 rpm and the ball milling time to 2 h to 6 h.

[0019] Furthermore, in step S2, the heating rate of the first stage of heating is 2℃ / min to 5℃ / min.

[0020] Furthermore, in step S2, nitrogen gas is continuously introduced into the reaction crucible during the first stage of heating reaction.

[0021] Furthermore, in step S3, the heating rate of the second stage is 10℃ / min to 20℃ / min.

[0022] Furthermore, in step S3, air, nitrogen, or an inert gas is continuously introduced into the reaction crucible during the second stage of heating reaction.

[0023] Furthermore, step S2 includes the following steps:

[0024] S21, add the ball-milled aluminum hydroxide powder to the reaction crucible, and use a microwave heating furnace to carry out the first stage of heating reaction. Set the initial reaction temperature to 30℃ and the termination temperature to 150℃~280℃.

[0025] S22, by controlling the power of the microwave magnetron, the heating rate is set to 5℃ / min, and nitrogen gas is continuously introduced during the heating reaction.

[0026] Furthermore, step S3 includes the following steps:

[0027] S31, After the first stage of heating reaction is completed, the second stage of heating reaction is carried out using a microwave heating furnace. The initial reaction temperature is set to 150℃~280℃ and the termination temperature is set to 300℃~400℃.

[0028] S32 controls the microwave magnetron power, sets the heating rate to 10℃ / min, and continuously introduces air, nitrogen, or inert gas during the heating reaction.

[0029] S32 was kept at the reaction termination temperature for 0.5 hours after it was reached.

[0030] To make the above features and effects of the present invention readily apparent, the following detailed description, in conjunction with the accompanying drawings, will provide a clear and complete account. Attached Figure Description

[0031] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0032] Figure 1 This is a flowchart of the method for preparing boehmite according to the present invention.

[0033] Figure 2 The X-ray diffraction (XRD) pattern of the boehmite material prepared according to the present invention.

[0034] Figure 3 This is a scanning electron microscope (SEM) image of the boehmite material prepared in this invention.

[0035] Figure 4 This is a transmission electron microscope (TEM) image of the boehmite material prepared in this invention. Detailed Implementation

[0036] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. The following description of at least one exemplary embodiment is merely illustrative and is in no way intended to limit the present invention or its application or use. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0037] Unless otherwise specifically stated, the numerical values ​​set forth in these embodiments do not limit the scope of the invention. Techniques and methods known to those skilled in the art may not be discussed in detail, but where appropriate, such techniques and methods should be considered part of the specification. In all examples shown and discussed herein, any specific values ​​should be interpreted as merely exemplary and not as limitations. Therefore, other examples of exemplary embodiments may have different values.

[0038] Experimental methods not specifically described in the following examples are generally determined according to national standards; if no corresponding national standard exists, they are performed according to generally accepted international standards or the standards proposed by relevant enterprises. Unless otherwise stated, all parts are parts by weight, and all percentages are weight percentages.

[0039] Reference Figures 1 to 4 The method for preparing boehmite according to the present invention includes the following steps:

[0040] S1. Place aluminum hydroxide in a ball mill jar and dry grind it using a planetary ball mill at a speed of 400 rpm to 800 rpm for 2 to 6 hours. Add 0.5 to 2 g of ball milling aid during the grinding process.

[0041] S2, the ball-milled aluminum hydroxide powder is placed in a crucible for the first stage of heating. The first stage of heating is from room temperature to 150℃~280℃. The heating rate of the first stage of heating is 2℃ / min~5℃ / min. Nitrogen gas is continuously introduced into the reaction crucible during the first stage of heating reaction.

[0042] S3, the second stage of heating is carried out, from 150℃~280℃ to 300℃~400℃, the heating rate of the second stage of heating is 10℃ / min~20℃ / min, during the second stage of heating reaction, air, nitrogen or inert gas is continuously introduced into the reaction crucible, and the reaction is held at the termination temperature for 0.5h.

[0043] S4, after the heating reaction is complete, cool to room temperature and collect the resulting white powder;

[0044] S5. The collected white powder is sieved and demagnetized to obtain the final product, boehmite.

[0045] Specifically, step S1 includes the following steps:

[0046] S11. Use an electronic balance to accurately weigh 0.5-1.5 kg of aluminum hydroxide powder and 0.5-2 g of caustic soda ball milling aid, and add them to the ball mill jar;

[0047] S12, using a planetary ball mill, the ball mill jar containing aluminum hydroxide and caustic soda powder is ball milled, with the ball mill speed set to 400 rpm to 800 rpm and the ball milling time to 2 h to 6 h.

[0048] Specifically, step S2 includes the following steps:

[0049] S21, add the ball-milled aluminum hydroxide powder to the reaction crucible, and use a microwave heating furnace to carry out the first stage of heating reaction. Set the initial reaction temperature to 30℃ and the termination temperature to 150℃~280℃.

[0050] S22, by controlling the power of the microwave magnetron, the heating rate is set to 5℃ / min, and nitrogen gas is continuously introduced during the heating reaction.

[0051] Specifically, step S3 includes the following steps:

[0052] S31, After the first stage of heating reaction is completed, the second stage of heating reaction is carried out using a microwave heating furnace. The initial reaction temperature is set to 150℃~280℃ and the termination temperature is set to 300℃~400℃.

[0053] S32 controls the microwave magnetron power, sets the heating rate to 10℃ / min, and continuously introduces air, nitrogen, or inert gas during the heating reaction.

[0054] S32 was kept at the reaction termination temperature for 0.5 hours after it was reached.

[0055] The preparation process of the composite current collector of the present invention will be described in detail below with reference to specific embodiments.

[0056] Example 1

[0057] S1: Commercially available aluminum hydroxide powder was selected as the reaction raw material. 0.5 kg of aluminum hydroxide was weighed using an electronic balance and placed in a ball mill jar. It was then dry-milled using a planetary ball mill at a speed of 400 rpm for 2 hours.

[0058] S2: Place the ball-milled aluminum hydroxide powder in a reaction crucible and carry out a two-stage heating reaction using a microwave heating furnace: The first stage heating program is set to heat from 30℃ to 150℃~280℃. By controlling the power of the microwave magnetron, the heating rate is set to 5℃ / min. Nitrogen gas is continuously introduced during the reaction.

[0059] S3: The second stage heating program is set to heat from 150℃ to 280℃ to 300℃. By controlling the power of the microwave magnetron, the heating rate is set to 10℃ / min. Nitrogen gas is continuously introduced during the reaction, and the temperature is held at the termination temperature of 300℃ for 0.5h.

[0060] S4: After the microwave heating reaction is complete, cool to room temperature and collect the white powder as the final product;

[0061] S5: The collected white powder is sieved and demagnetized to obtain the final product.

[0062] Example 2

[0063] S1: Commercially available aluminum hydroxide powder was selected as the reaction raw material. 1 kg of aluminum hydroxide was weighed using an electronic balance and placed in a ball mill jar. It was then dry-milled using a planetary ball mill at a speed of 600 rpm for 4 hours.

[0064] S2: Place the ball-milled aluminum hydroxide powder in a crucible and carry out a two-stage heating reaction using a microwave heating furnace: The first stage heating program is set to heat from 30℃ to 150℃~280℃, and the heating rate is set to 5℃ / min by controlling the power of the microwave magnetron. Nitrogen gas is continuously introduced during the reaction.

[0065] S3: The second stage heating program is set to heat from 150℃ to 280℃ to 350℃. By controlling the power of the microwave magnetron, the heating rate is set to 10℃ / min. Nitrogen gas is continuously introduced during the reaction, and the temperature is held at the termination temperature of 350℃ for 0.5h.

[0066] S4: After the microwave heating reaction is complete, cool to room temperature and collect the white powder as the final product;

[0067] S5: The collected white powder is sieved and demagnetized to obtain the final product.

[0068] Example 3

[0069] S1: Commercially available aluminum hydroxide powder was selected as the reaction raw material. 1.5 kg of aluminum hydroxide was weighed using an electronic balance and placed in a ball mill jar. It was then dry-milled using a planetary ball mill at a speed of 800 rpm for 6 hours.

[0070] S2: Place the ball-milled aluminum hydroxide powder in a crucible and use microwave heating to carry out a two-stage heating reaction: The first stage heating program is set to heat from 30℃ to 150℃~280℃. By controlling the power of the microwave magnetron, the heating rate is set to 5℃ / min. Nitrogen gas is continuously introduced during the reaction.

[0071] S3: The second stage heating program is set to heat from 150℃ to 280℃ to 400℃. By controlling the power of the microwave magnetron, the heating rate is set to 10℃ / min. Nitrogen gas is continuously introduced during the reaction, and the temperature is held at the termination temperature of 400℃ for 0.5h.

[0072] S4: After the microwave heating reaction is completed, cool to room temperature and collect the white powder as the final product; S5: sieve the collected white powder to remove magnetism and obtain the final product.

[0073] The beneficial effects of this invention are as follows: The boehmite preparation method of this invention has a simple synthesis process, high safety, low equipment requirements, low cost, and excellent economic efficiency. The phase analysis of the product synthesized by this method by X-ray diffraction (XRD) shows that the diffraction peaks mainly come from the characteristic peaks of boehmite. Scanning electron microscopy (SEM) images show that the average size of the synthesized boehmite is about 500 nm and relatively uniform. Compared with the existing boehmite materials obtained by hydrothermal reaction, the particle size is smaller and the uniformity is better.

[0074] Based on the above-described preferred embodiments of the present invention, and through the foregoing description, those skilled in the art can make various changes and modifications without departing from the inventive concept. The technical scope of this invention is not limited to the contents of the specification, but must be determined by the scope of the claims.

Claims

1. A method for preparing boehmite, characterized in that, Includes the following steps: S1, aluminum hydroxide is placed in a ball mill jar and dry-milled using a planetary ball mill; S2, the ball-milled aluminum hydroxide powder is placed in a crucible for the first stage of heating, which starts from room temperature and heats to 200°C. S3, the second stage of heating is carried out, from 200℃ to 300℃~400℃, and held at the reaction termination temperature for 0.5h; S4, after the heating reaction is complete, cool to room temperature and collect the resulting white powder; S5. The collected white powder is sieved and demagnetized to obtain the final product, boehmite. Step S2 includes the following steps: S21, add the ball-milled aluminum hydroxide powder to the reaction crucible, and use a microwave heating furnace to carry out the first stage of heating reaction, setting the initial reaction temperature to 30℃ and the termination temperature to 200℃; S22, by controlling the power of the microwave magnetron, the heating rate is set to 5℃ / min, and nitrogen gas is continuously introduced during the heating reaction; Step S3 includes the following steps: S31, After the first stage of heating reaction is completed, the second stage of heating reaction is carried out using a microwave heating furnace. The initial reaction temperature is set to 200℃ and the termination temperature is 300℃~400℃. S32 controls the microwave magnetron power, sets the heating rate to 10℃ / min, and continuously introduces air, nitrogen, or inert gas during the heating reaction. S32 was kept at the reaction termination temperature for 0.5 hours after it was reached.

2. The method for preparing boehmite as described in claim 1, characterized in that: In step S1, the ball milling speed is 400 rpm to 800 rpm; the ball milling time is 2 h to 6 h.

3. The method for preparing boehmite as described in claim 1, characterized in that: In step S1, 0.5–2 g of ball milling aid is added during the ball milling process.

4. The method for preparing boehmite as described in claim 1, characterized in that: Step S1 includes the following steps: S11. Use an electronic balance to accurately weigh 0.5-1.5 kg of aluminum hydroxide powder and 0.5-2 g of caustic soda ball milling aid, and add them to the ball mill jar; S12, using a planetary ball mill, the ball mill jar containing aluminum hydroxide and caustic soda powder is ball milled, with the ball mill speed set to 400 rpm to 800 rpm and the ball milling time to 2 h to 6 h.

5. The method for preparing boehmite as described in claim 1, characterized in that: In step S2, the heating rate of the first stage of heating is 2℃ / min to 5℃ / min.

6. The method for preparing boehmite as described in claim 1, characterized in that: In step S2, nitrogen gas is continuously introduced into the reaction crucible during the first stage of heating reaction.

7. The method for preparing boehmite as described in claim 1, characterized in that: In step S3, the heating rate of the second stage is 10℃ / min to 20℃ / min.

8. The method for preparing boehmite as described in claim 1, characterized in that: In step S3, air, nitrogen, or an inert gas is continuously introduced into the reaction crucible during the second stage of heating reaction.

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