CN116062780A - Preparation method of boehmite slurry, boehmite slurry and application thereof - Google Patents

Abstract

The present application relates to a preparation method of boehmite slurry, comprising the steps of: grinding aluminum hydroxide to a predetermined particle size and preparing an aluminum hydroxide dispersion with water; subjecting the aluminum hydroxide dispersion to a hydrothermal reaction, obtaining a boehmite dispersion; filtering the boehmite dispersion to obtain a filter residue, and mixing the filter residue with a dispersant to obtain a slurry. The preparation method of the boehmite slurry provided in the embodiment of the present application directly selects aluminum hydroxide as a single aluminum source, and uses hydrothermal reaction to convert aluminum hydroxide into γ-phase alumina monohydrate to form boehmite, and then the boehmite After filtering out, the boulder is directly mixed with a dispersant to obtain a slurry, which saves the step of drying, so this application has the effects of low raw material cost, simple process, and no drying process.

Description

Preparation method of boehmite slurry, boehmite slurry and application thereof

technical field

The present application relates to the field of lithium batteries, in particular to boehmite slurry used for lithium battery diaphragms.

Background technique

With the rapid development of lithium battery materials in recent years, in the upstream diaphragm field, the demand for ternary materials has driven the rapid increase in the demand for diaphragm coating to meet the strong demand for products from downstream customers. The main function of the separator is to separate the positive and negative poles of the battery, prevent the two poles from contacting and cause short circuit, and also play the role of electrolyte ion channel. At present, alumina and boehmite are one of the important raw materials for lithium-ion battery separator coating materials, which will have an important impact on the properties of lithium-ion battery separators.

In the current preparation methods of boehmite, there are mainly aluminum salt hydrolysis method, hydrothermal method, sol-gel method, etc. The existing preparation methods often need to use various aluminum sources such as aluminum-containing organic matter and aluminum hydroxide. Sometimes it is necessary to use organic solvents such as N-methylpyrrolidone, the cost of raw materials is high, and the process is more complicated; and the existing boehmite preparation method finally obtains dried boehmite powder, and the drying process may Impurities will be introduced.

Contents of the invention

The embodiment of the present application provides the preparation method of boehmite slurry, boehmite slurry and its application to solve the problems of high raw material cost, complicated process and impurities introduced in the drying process in the preparation of boehmite slurry. technical problem.

In the first aspect, the embodiment of the present application provides a method for preparing boehmite slurry, and the method for preparing boehmite slurry includes the following steps:

Grind aluminum hydroxide to a predetermined particle size and prepare aluminum hydroxide dispersion with water;

subjecting the aluminum hydroxide dispersion to a hydrothermal reaction to obtain a boehmite dispersion;

Filtrating the boehmite dispersion liquid to obtain a filter residue, and mixing the filter residue with a dispersant to obtain a slurry.

In some embodiments of the present application, the predetermined particle size is D50=0.8-1.2um.

In some embodiments of the present application, the particle size of the aluminum hydroxide is D50=2-5um.

In some embodiments of the present application, the mass concentration of the aluminum hydroxide dispersion is 200-300 g/L.

In some embodiments of the present application, the temperature of the hydrothermal reaction is 180-220°C; and/or,

The time of the hydrothermal reaction is 1-5h.

In some embodiments of the present application, the dispersant is a polycarboxylate suspending agent.

In some embodiments of the present application, the filter residue is mixed with a dispersant, and the mixing is performed at a stirring rate of 3000-8000 r/min for 0.5-1 h.

In a second aspect, embodiments of the present application provide a boehmite slurry, which is prepared by the method for preparing boehmite slurry in any embodiment of the first aspect.

In some embodiments of the present application, the concentration of the boehmite slurry is 45-50%.

In a third aspect, an embodiment of the present application provides an application of a boehmite slurry, the boehmite slurry is the boehmite slurry described in any embodiment of the second aspect, and the boehmite slurry Applied to the coating of lithium battery separator.

Compared with the prior art, the above-mentioned technical solutions provided by the embodiments of the present application have the following advantages:

The preparation method of the boehmite slurry provided in the embodiment of the present application directly selects aluminum hydroxide as a single aluminum source, and uses hydrothermal reaction to convert aluminum hydroxide into γ-phase alumina monohydrate to form boehmite, and then the boehmite After filtering out, the boulder is directly mixed with a dispersant to obtain a slurry, which saves the step of drying, so this application has the effects of low raw material cost, simple process, and no drying process.

Description of drawings

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

In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings that need to be used in the description of the embodiments or the prior art. Obviously, for those of ordinary skill in the art, In other words, other drawings can also be obtained from these drawings without paying creative labor.

Fig. 1 is the schematic flow chart of the preparation method of a kind of boehmite slurry provided by the embodiment of the present application;

Fig. 2 is the SEM image of the powder obtained by drying the boehmite slurry in Example 1 of the present application at a magnification of 2000;

Fig. 3 is the SEM image of the powder obtained by drying the boehmite slurry in Example 1 of the present application at a magnification of 10,000;

Fig. 4 is a table showing the viscosity change of the boehmite slurry obtained in Example-3 and Comparative Example 1-2 of the present application.

Detailed ways

In order to make the purposes, technical solutions and advantages of the embodiments of the present application clearer, the technical solutions 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 It is a part of the embodiments of this application, but not all of them. Based on the embodiments in the present application, all other embodiments obtained by persons of ordinary skill in the art without making creative efforts belong to the protection scope of the present application.

Unless otherwise specified, terms used herein should be understood as commonly used in the art. Therefore, unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. In case of conflict, this specification shall take precedence.

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.

The preparation of the existing boehmite slurry has the technical problems of high raw material cost, complicated process, and impurities introduced in the drying process.

The technical solutions provided by the embodiments of the present application are to solve the above technical problems, and the general idea is as follows:

In the first aspect, the embodiment of the present application provides a method for preparing boehmite slurry, please refer to Figure 1, the method for preparing boehmite slurry includes the following steps:

S1: Grind aluminum hydroxide to a predetermined particle size and prepare aluminum hydroxide dispersion with water;

S2: subjecting the aluminum hydroxide dispersion to a hydrothermal reaction to obtain a boehmite dispersion;

S3: filtering the boehmite dispersion to obtain a filter residue, and mixing the filter residue with a dispersant to obtain a slurry.

In step S2, the hydrothermal reaction can convert aluminum hydroxide into γ-phase aluminum oxide monohydrate, that is, the crystal phase of boehmite.

The main function of the dispersant in step S3 is to enable the boehmite in the form of particles to be suspended in water more stably. The dispersant can be selected from general surfactants.

This application directly selects aluminum hydroxide as a single aluminum source, and uses hydrothermal reaction to convert aluminum hydroxide into γ-phase alumina monohydrate to form boehmite, then filter the boehmite and directly mix it with a dispersant to obtain a slurry , the step of drying is omitted, so the application has the effects of low raw material cost, simple process, and no drying process.

In some embodiments of the present application, the predetermined particle size is D50=0.8-1.2um.

The beneficial effect of controlling the predetermined particle size to D50=0.8-1.2um is that the aluminum hydroxide dispersion with good dispersion effect can be obtained, and the particle size of the boehmite in the boehmite dispersion will not be too small to cause filtration difficulties .

In some embodiments of the present application, the particle size of the aluminum hydroxide is D50=2-5um.

The beneficial effect of selecting the particle size of the aluminum hydroxide as D50=2-5um is that it is easy to control the grinding effect, so that the grinding can reach a predetermined particle size.

In some embodiments of the present application, the mass concentration of the aluminum hydroxide dispersion is 200-300 g/L.

The beneficial effect of controlling the mass concentration of the aluminum hydroxide dispersion to 200-300g/L is that it can maintain a good dispersion effect, ensure that the phenomenon of particle agglomeration in the hydrothermal reaction process is less, and prevent the filtration due to too low concentration. too long.

In some embodiments of the present application, the temperature of the hydrothermal reaction is 180-220°C; and/or,

The time of the hydrothermal reaction is 1-5h.

The temperature of the hydrothermal reaction is 180-220°C, which is conducive to the transformation of aluminum hydroxide into γ-phase aluminum oxide monohydrate.

The beneficial effect of controlling the time of the hydrothermal reaction to 1-5 hours is that the hydrothermal reaction can be fully carried out, and the particles will not be agglomerated due to too long heating time.

In some embodiments of the present application, the dispersant is a polycarboxylate suspending agent.

There are a lot of hydroxyl groups on the surface of boehmite, and the polycarboxylate suspending agent can have a good suspending effect on boehmite.

In some embodiments of the present application, the filter residue is mixed with a dispersant, and the mixing is performed at a stirring rate of 3000-8000 r/min for 0.5-1 h.

In a second aspect, embodiments of the present application provide a boehmite slurry, which is prepared by the method for preparing boehmite slurry in any embodiment of the first aspect. Since the boehmite slurry is implemented based on the first aspect, it has all the beneficial effects of the first aspect, and will not be repeated here.

In some embodiments of the present application, the concentration of the boehmite slurry is 45-50%.

The boehmite slurry with the above concentration can not only maintain a relatively stable suspension state, but also have a good coating effect on the lithium battery separator.

In a third aspect, an embodiment of the present application provides an application of a boehmite slurry, the boehmite slurry is the boehmite slurry described in any embodiment of the second aspect, and the boehmite slurry Applied to the coating of lithium battery separator. Since the application of the boehmite slurry is implemented based on the second aspect, it has all the beneficial effects of the second aspect, and will not be repeated here.

The present application will be further elaborated below in conjunction with specific embodiments. It should be understood that these examples are only used to illustrate the present application and are not intended to limit the scope of the present application. The experimental methods not indicating specific conditions in the following examples are usually measured according to national standards. If there is no corresponding national standard, proceed according to general international standards, conventional conditions, or the conditions suggested by the manufacturer.

Example 1

The present embodiment provides a kind of preparation method of boehmite slurry, comprising the following steps:

Sa: Add 200g of aluminum hydroxide with a particle size of D50=2um in 500ml of water and stir to make it completely dispersed, grind the obtained liquid until the particle size of aluminum hydroxide is D50=0.8um, add 500ml of pure water to obtain aluminum hydroxide dispersion liquid.

Sb: transfer the aluminum hydroxide dispersion to a hydrothermal kettle and react at 200° C. for 2 hours.

Sc: Cool the reactant to below 80°C, filter to obtain a boehmite filter cake, mix the filter cake with 200ml dispersant at a stirring rate of 5000r/min for 1 hour to obtain the boehmite slurry material.

Wherein said dispersant is a polycarboxylate suspending agent.

Example 2

The present embodiment provides a kind of preparation method of boehmite slurry, comprising the following steps:

Sa: Add 200g of aluminum hydroxide with a particle size of D50=5um in 500ml of water and stir to make it completely dispersed, grind the obtained liquid until the particle size of aluminum hydroxide is D50=1.2um, add 500ml of pure water to obtain aluminum hydroxide dispersion liquid.

Sb: transfer the aluminum hydroxide dispersion to a hydrothermal kettle and react at 180° C. for 2 hours.

Sc: Cool the reactant to below 80°C, filter to obtain a boehmite filter cake, mix the filter cake with 100ml dispersant at a stirring rate of 3000-8000r/min for 0.5-1h to obtain the Boehmite slurry.

Wherein said dispersant is a polycarboxylate suspending agent.

Example 3

The present embodiment provides a kind of preparation method of boehmite slurry, comprising the following steps:

Sa: Add 200g of aluminum hydroxide with a particle size of D50=3um in 500ml of water and stir to make it completely dispersed, grind the obtained liquid until the particle size of aluminum hydroxide is D50=0.9um, add 500ml of pure water to obtain aluminum hydroxide dispersion liquid.

Sb: transfer the aluminum hydroxide dispersion to a hydrothermal kettle and react at 200° C. for 5 hours.

Sc: Cool the reactant to below 80°C, filter to obtain a boehmite filter cake, mix the filter cake with 300ml dispersant at a stirring rate of 5000r/min for 1 hour to obtain the boehmite slurry material.

Wherein said dispersant is a polycarboxylate suspending agent.

Comparative example 1

This comparative example provides a kind of preparation method of boehmite slurry, comprises the steps:

Sa: Add 200g of aluminum hydroxide with a particle size of D50=2-5um in 500ml of water and stir to make it completely dispersed, grind the obtained liquid until the particle size of aluminum hydroxide is D50=0.8-1.2um, add 500ml of pure water to obtain Aluminum hydroxide dispersion.

Sb: transfer the aluminum hydroxide dispersion to a hydrothermal kettle and react at 200° C. for 2 hours.

Sc: Cool the reactant to below 80°C, filter to obtain a boehmite filter cake, mix the filter cake with 200ml of water at a stirring rate of 5000r/min for 1 hour to obtain the boehmite slurry .

Wherein said dispersant is a polycarboxylate suspending agent.

Comparative example 2

This comparative example provides a kind of preparation method of boehmite slurry, comprises the steps:

Sa: Add 200g of aluminum hydroxide with a particle size of D50=7um in 500ml of water and stir to make it completely dispersed, grind the obtained liquid until the particle size of aluminum hydroxide is D50=1.4um, add 500ml of pure water to obtain aluminum hydroxide dispersion liquid.

Sb: transfer the aluminum hydroxide dispersion to a hydrothermal kettle and react at 200° C. for 2 hours.

Sc: Cool the reactant to below 80°C, filter to obtain a boehmite filter cake, mix the filter cake with 200ml dispersant at a stirring rate of 5000r/min for 1 hour to obtain the boehmite slurry material.

Wherein said dispersant is a polycarboxylate suspending agent.

Relevant experiments and effect data:

The boehmite slurry obtained in Example 1 was dried to obtain boehmite powder, and the boehmite powder was tested by a scanning electron microscope. Please refer to Fig. 2-Fig. 3 for the results. Figure 2 and Figure 3 show that Example 1 has obtained boehmite with a relatively uniform particle size.

Laser particle size distribution test was carried out on the above boehmite powder, please refer to Figure 4 for the results.

Take the boehmite slurry newly prepared in Example 1-3 and Comparative Example 1-2 and let it stand at 25°C, during which the viscosity was tested continuously, and the results are shown in the following table.

Initial viscosity (mPa·s) Viscosity after 10 days (mPa·s) suspension performance Example 1 20 18 good Example 2 57 98 generally Example 3 twenty two twenty four good Comparative example 1 500 800 Difference Comparative example 2 126 180 generally

Various embodiments of the present application may exist 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 construed as a rigid limitation on the scope of the application; therefore, the described range should be regarded as The description has specifically disclosed all possible subranges as well as individual values within that range. For example, a description of a range from 1 to 6 should be considered to have specifically disclosed subranges, 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., and Single numbers within the stated ranges, eg 1, 2, 3, 4, 5 and 6, apply regardless of the range. Additionally, whenever a numerical range is indicated herein, it is meant to include any cited numeral (fractional or integral) within the indicated range.

In the present application, unless otherwise stated, the used orientation words such as "upper" and "lower" specifically refer to the direction of the drawings in the drawings. In addition, in the description of the specification of the present application, the terms "including" and "comprising" mean "including but not limited to". Furthermore, the term "comprises", "comprises" or any other variation thereof is intended to cover a non-exclusive inclusion such that a process, method, article, or apparatus comprising a set of elements includes not only those elements, but also includes elements not expressly listed. other elements of or also include elements inherent in such a process, method, article, or device. Without further limitations, an element defined by the statement "comprising..." does not exclude the presence of additional same elements in the process, method, article or device comprising said element. In this document, relational terms such as "first" and "second", etc., are only used to distinguish one entity or operation from another, and do not necessarily require or imply that there is a relationship between these entities or operations. There is no such actual relationship or sequence. In this article, "and/or" describes the association relationship of associated objects, indicating that there may be three kinds of relationships, for example, A and/or B, which can mean: A exists alone, A and B exist simultaneously, and B exists alone . For the association relationship of more than three associated objects described with "and/or", it means that any of the three associated objects can exist independently, or any at least two of them can exist at the same time, for example, for A, and/or B , and/or C, may mean that any one of A, B, and C exists alone, or any two of them exist simultaneously, or three of them exist simultaneously. Herein, "at least one" means one or more, and "plurality" means 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 a single item or a plurality of items. For example, "at least one item (unit) of a, b, or c", or "at least one item (unit) of a, b, and c" can mean: a, b, c, a-b( That is, a and b), a-c, b-c, or a-b-c, where a, b, and c can be single or multiple.

The above descriptions are only specific implementation manners 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 readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of the application. Therefore, the present application will not be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed herein.

Claims (10)

1. a preparation method of boehmite slurry, is characterized in that, the preparation method of described boehmite slurry comprises the steps: Grind aluminum hydroxide to a predetermined particle size and prepare aluminum hydroxide dispersion with water; subjecting the aluminum hydroxide dispersion to a hydrothermal reaction to obtain a boehmite dispersion; Filtrating the boehmite dispersion liquid to obtain a filter residue, and mixing the filter residue with a dispersant to obtain a slurry. 2. The method for preparing boehmite slurry according to claim 1, characterized in that, the predetermined particle size is D50=0.8-1.2um. 3. The method for preparing boehmite slurry according to claim 2, characterized in that the particle size of the aluminum hydroxide is D50=2-5um. 4. The preparation method of boehmite slurry according to claim 3, characterized in that, the mass concentration of the aluminum hydroxide dispersion is 200-300g/L. 5. The method for preparing boehmite slurry according to claim 1, characterized in that, the temperature of the hydrothermal reaction is 180-220°C; and/or, The time of the hydrothermal reaction is 1-5h. 6. The preparation method of boehmite slurry according to claim 1, characterized in that, the dispersant is a polycarboxylate suspending agent. 7. The preparation method of boehmite slurry according to claim 1, characterized in that, the filter residue is mixed with a dispersant, and the mixing is carried out at a stirring rate of 3000-8000r/min for 0.5 -1h. 8. A boehmite slurry, characterized in that the boehmite slurry is prepared by the method for preparing boehmite slurry according to any one of claims 1-7. 9. The boehmite slurry according to claim 8, characterized in that the concentration of the boehmite slurry is 45-50%. 10. The application of a kind of boehmite slurry, it is characterized in that, described boehmite slurry is the boehmite slurry described in claim 9, and described boehmite slurry is applied to the coating of lithium battery diaphragm apply.

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