Composite high-viscosity powder acoustic resonance deagglomeration method capable of adjusting shearing effect

Abstract

The invention belongs to the technical field of new materials, and relates to a composite high-viscosity powder acoustic resonance deagglomeration method capable of adjusting a shearing effect. According to the method, a fixed shearing grating is designed in an acoustic resonance mixing container, high momentum of materials in a resonance state and mutual collision shearing of the grating are promoted by adjusting grating gaps and acoustic resonance mixing parameters, and an adjustable shearing effect can be applied to high-viscosity powder with the Karl index larger than or equal to 20 in the acoustic resonance process. And the purpose of deagglomeration of the high-viscosity powder is achieved. The method provided by the invention is simple in process and convenient to operate, can avoid risks of raw material pollution, excessive loss and the like, and can be applied to high-viscosity powder which is difficult to realize ball material screening.

Description

Technical Field

[0001] The present invention belongs to the technical field of new materials and relates to a high-viscosity powder acoustic resonance deagglomeration method with a composite adjustable shearing effect. Background Art

[0002] The acoustic resonance technology is a new mixing method based on the coupling effect of macroscopic mechanical vibration mixing and microscopic acoustic streaming mixing. Under high-intensity resonance excitation, different mixed materials all generate large amplitudes. At the same time, the low-frequency sound waves excited by the resonance excitation in the multiphase flow propagate along different routes, forming countless acoustic streaming vortices while the whole field is fluidized to accelerate homogeneous mixing and achieve efficient paddleless mixing. Given the above advantages, this method has been applied to many fields including military explosives and superhard materials.

[0003] However, for ultrafine powders, due to their high surface energy, primary particles with a particle size less than 1 μm often cannot exist alone, but exist stably by agglomerating with each other to reduce the surface energy, and the agglomeration scale can reach more than 5 - 10 μm. The powerful vibration energy generated by the acoustic resonance mixing technology can only make the mixed raw materials move sufficiently to change the relative positions between the agglomerates, but because the shearing effect is too weak, it cannot specifically achieve deagglomeration. Patent document CN115815607B discloses a composite high-energy ball milling acoustic resonance mixing method, which realizes the crushing and deagglomeration of raw materials through the strong shearing effect generated by mutual grinding of appropriate proportions of ball milling media while performing acoustic resonance mixing. However, under the long-term ball milling action, a part of the raw materials will adsorb and adhere to the surface of the ball milling media, resulting in deviation of the actual composition of the raw materials; more importantly, after the material is mixed and processed, the ball milling media needs to be screened out through a sieve mesh. Some materials are extremely easy to block the mesh holes of the sieve mesh during the screening process, resulting in low powder screening efficiency, large raw material loss, and even the problem of re-agglomeration of ultrafine powders.

[0004] As the particle size of the powder decreases, the adsorption effect between the powders gradually increases, and characteristics such as high viscosity and poor fluidity of the material severely limit the process conditions for powder mixing and deagglomeration. For high-viscosity powders, a single acoustic resonance mixing method cannot solve the problem of agglomeration of ultrafine powders in the material, and the acoustic resonance method of composite ball milling cannot be applied because it cannot separate high-viscosity powders and ball milling media. Therefore, there is an urgent need for a method without adding external ball milling media, which can not only give full play to the advantages of high efficiency and high energy of acoustic resonance, but also assist in deagglomeration with an adjustable shearing effect. Summary of the Invention

[0005] Based on this, the object of the present invention is to provide a method for acoustic resonance deagglomeration of high-viscosity powders with a composite adjustable shearing effect. By designing a fixed shearing grid in the acoustic resonance mixing container and adjusting the grid gap and acoustic resonance mixing parameters, the high momentum of the material under resonance and the grid collide and shear each other, enabling an adjustable shearing effect to be exerted on the high-viscosity powders during the acoustic resonance process, thereby achieving the purpose of deagglomerating the high-viscosity powders.

[0006] The present invention also provides an acoustic resonance mixing container with a grid installed inside used in this deagglomeration method, the ultrafine powder prepared thereby, and the applications of the powder in the preparation of new energy battery materials, the preparation of superhard materials, and powder metallurgy.

[0007] To achieve the above object, the present invention adopts the following technical solutions: The present invention provides a method for acoustic resonance deagglomeration of high-viscosity powders with a composite adjustable shearing effect. The high-viscosity powders are filled into an acoustic resonance mixing container with a grid installed inside. After the acoustic resonance mixing container is sealed, it is fixed in an acoustic resonance device. After evacuating and setting the corresponding process parameters, the acoustic resonance device is started to deagglomerate the high-viscosity powders.

[0008] Further, the grid is composed of a support member and a shearing edge. The shearing edge is strip-shaped, and each shearing edge is installed parallel to each other on the support member to form a grid plane. The gap between adjacent shearing edges is 3 - 10 mm; the shearing edge is in a blade shape in the direction perpendicular to the grid plane.

[0009] Further, the number of grids ≥ 1 layer, and they are installed on the container wall at different heights from the bottom inside the acoustic resonance mixing container and are fixedly connected in a fitting manner with the container wall; the grid plane is parallel to the bottom surface of the acoustic resonance mixing container; in a top view state, a direction angle is formed between the shearing edges of adjacent layers of grids, and the direction angle includes a complementary small angle and a large angle.

[0010] Further, the number of grids is 3 layers. The first layer grid, the second layer grid, and the third layer grid are respectively installed on the container wall at 1 / 3, 1 / 2, and 2 / 3 heights from the bottom inside the acoustic resonance mixing container; in a top view state, the small angle in the direction angle formed between the shearing edges of adjacent layers of grids is 60°.

[0011] Further, the parameters of the acoustic resonance device are: the resonance mixing frequency is 55.0 - 70.0 Hz, the resonance intensity is an acceleration of 300 - 1100 m / s 2 , and the temperature is 20 - 30 °C.

[0012] Further, the Carr index of the high-viscosity powders ≥ 20.

[0013] Furthermore, the volume ratio of the high-viscosity powder filled in the acoustic resonance mixing container is 30% - 70%.

[0014] The present invention further provides an acoustic resonance mixing container with a grid installed inside, which is used in the above-mentioned deflocculation method.

[0015] The present invention further provides an ultrafine powder prepared by the above-mentioned deflocculation method.

[0016] The present invention further provides an application of the above ultrafine powder in the preparation of new energy battery materials, the preparation of superhard materials, and powder metallurgy.

[0017] The beneficial effects of the present invention are as follows: 1. The high-viscosity powder acoustic resonance deflocculation method with a composite adjustable shearing effect provided by the present invention effectively combines a shearing grid and an acoustic resonance mixing technology. Under the resonance state, the shearing grid can replace high-energy ball milling, and the generated shearing effect can assist the whole-field mixing to effectively achieve deflocculation of ultrafine powders, and can be applied to high-viscosity powders where ball milling cannot be implemented. 2. The high-viscosity powder acoustic resonance deflocculation method with a composite adjustable shearing effect provided by the present invention can adjust the shearing effect of the mixed materials by adjusting the gap of the shearing grid and the acoustic resonance parameters, so that the high momentum of the material under the resonance state collides and shears with the grid to different degrees, and can be applied to materials with different viscosities.

[0018] 3. The high-viscosity powder acoustic resonance deflocculation method with a composite adjustable shearing effect provided by the present invention, which is a deflocculation method without ball milling media, can effectively avoid problems such as unnecessary composition deviation and raw material loss, and at the same time can also simplify and omit the ball-material separation process, and the process is simpler and faster, providing a new idea for the deflocculation and mixing of high-viscosity powders.

[0019] 4. The ultrafine powder obtained by using the high-viscosity powder acoustic resonance deflocculation method with a composite adjustable shearing effect provided by the present invention can be widely applied in the preparation of new energy battery materials, the preparation of superhard materials, and powder metallurgy. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the technical solutions of the present invention, the following will briefly introduce the drawings required for the description of the embodiments or the prior art. Obviously, the following drawings are only some embodiments of the present invention. For those of ordinary skill in the art, other drawings can be obtained based on these drawings without creative efforts.

[0021] Attached Figure 1 is a schematic diagram of the deflocculation process of high-viscosity powder in an acoustic resonance mixing container with a grid installed inside in the present invention; Attached Figure 2Schematic diagram of the grille structure in the present invention; Appendix Figure 3 Schematic diagram of the installation direction and included angle of adjacent grilles in the present invention in a top view state in the acoustic resonance mixing container; Appendix Figure 4 SEM image of the deagglomerated nano-carbon powder in the flake graphite powder in Example 1 of the present invention, with the scale bar being 50 μm; Appendix Figure 5 SEM image of the deagglomerated nano-cobalt powder in the tungsten carbide powder in Example 2 of the present invention, with the scale bar being 50 μm; Appendix Figure 6 SEM image of the deagglomerated magnesium oxide powder in the niobium oxide powder in Example 3 of the present invention, with the scale bar being 50 μm; Appendix Figure 7 SEM image of the deagglomerated nano-carbon powder in the flake graphite powder in Comparative Example 1 of the present invention, with the scale bar being 50 μm. Detailed implementation manners

[0022] Next, the technical solutions in the embodiments of the present invention will be clearly and completely described in conjunction with the accompanying drawings. The mentioned embodiments are all implemented on the premise of the technical solutions of the present invention, and the detailed implementation processes are given. However, it should be stated that the protection scope of the present invention is not limited to the following embodiments.

[0023] The following embodiments list the detailed implementation processes for the technical solutions of the present invention. Unless otherwise specified, the test methods used in the following experimental examples are all conventional methods; the materials, reagents, etc. used, unless otherwise specified, are reagents and materials that can be obtained from commercial channels.

[0024] The acoustic resonance device adopted in the present invention is an acoustic resonance mixer, and the structure of this device is a conventional structure in the art.

[0025] By designing a fixed shear grille in the acoustic resonance mixing container of the acoustic resonance mixer in the present invention and adjusting the grille gap and acoustic resonance mixing parameters, the high momentum of the material under the resonance state and the grille can collide and shear with each other, so as to achieve an adjustable shear effect on the high-viscosity powder during the acoustic resonance process and achieve the purpose of deagglomerating the high-viscosity powder.

[0026] In the present invention, the number of grids installed in the acoustic resonance mixing container is ≥ 1 layer. The more the number of grid layers, the stronger the shearing effect on the high-viscosity powder, and the better the deflocculation effect. After the number of layers reaches a certain amount, the deflocculation effect on the material tends to saturate. The grids are installed on the container wall at different heights from the bottom inside the acoustic resonance mixing container and are fixedly connected in fit with the container wall; the grid plane is parallel to the bottom surface of the acoustic resonance mixing container; in the top view state, a direction angle is formed between the shear edges of adjacent layers of grids, and the direction angle includes a complementary small angle and a large angle; the shear edges of adjacent layers of grids cross to form a mesh through which the material can pass. By changing the size of the direction angle, the shape and size of the mesh can be changed, and then different shearing effects can be produced on the material.

[0027] In the following embodiments of the present invention, the high-viscosity powder is deflocculated in an acoustic resonance mixing container internally installed with grids, as Figure 1 shown. In this acoustic resonance mixing container, the grid plane is parallel to the bottom surface of the acoustic resonance mixing container, and the number is 3 layers. The first-layer grid, the second-layer grid, and the third-layer grid are respectively installed on the container wall at 1 / 3, 1 / 2, and 2 / 3 of the distance from the bottom inside the acoustic resonance mixing container and are fixedly connected in fit with the container wall.

[0028] The schematic diagram of the grid structure is as Figure 2 shown. The schematic diagram of a single-layer grid shows that the grid is in a disc shape and is composed of a peripheral support member and several internal shear edges. Each shear edge is installed parallel to each other on the support member to form a grid plane. The shear edge is in a strip shape, and the gap between adjacent shear edges is 3 - 10 mm. The shear edge is in a blade shape in the direction perpendicular to the grid plane. The cross-sectional view of the single-layer grid shows that the cross-section of the shear edge can be a quadrangular prism shape, and each edge of the quadrangular prism is a blade. The material of the grid is stainless steel with a hard alloy coating on the surface. The grade of the hard alloy is YG6, and the coating thickness is 50 - 500 nm.

[0029] As Figure 3 shown, after the three-layer grids are installed, a direction angle is formed between the shear edges of adjacent layers of grids, and the direction angle includes a complementary small angle and a large angle. Preferably, to improve the shearing effect, in the top view state, the small angle in the direction angle formed between the shear edges of adjacent layers of grids is 60°, that is, both the small angle 1 formed between the shear edges of the first-layer grid and the second-layer grid and the small angle 2 formed between the shear edges of the second-layer grid and the third-layer grid are 60°. At this time, the maximum size of the mesh through which the material can pass is relatively small, and a good shearing effect can be produced on the material.

[0030] Example 1 Step 1: In this embodiment, the mixed raw material is a mixed powder of flake graphite and nano-carbon powder. The Carr index of the powder is about 20. After weighing, the loose-packed volume of the mixed raw material is 250 mL in total; Step 2: Prepare the shearing grid with the grid gap controlled at 3 mm. Fix the grids successively at the heights of 1 / 3, 1 / 2, and 2 / 3 from the bottom inside the 500 mL mixing container, and the included angle between adjacent grids is 60°; Step 3: Load the mixed raw materials into the mixing container, and the filling volume ratio of the materials is about 50%; Step 4: Fix the loaded mixing container on the vibrating table of the acoustic resonance mixing device, evacuate to 1 kPa, set the resonance frequency to 70 Hz, and set the resonance intensity to an acceleration of 300 m / s 2 , and start the resonance mixing. Control the process temperature at 25 °C; Step 5: Collect the mixed materials in Step 4 from the container to complete the mixing process.

[0031] As Figure 4 shown, after the nano carbon powder is deagglomerated in the flake graphite powder and detected by SEM, under the shearing effect introduced in the mixing container with the set parameters, the nano carbon powder agglomeration can be deagglomerated to 1 - 10 μm.

[0032] Example 2 Step 1: In this example, the mixed raw materials are a mixed powder of tungsten carbide powder and nano cobalt powder. The average particle size of the tungsten carbide powder is 300 nm, the Carr index of the mixed powder is about 30, and the loose bulk volume of the weighed mixed raw materials is 100 mL in total; Step 2: Prepare the shearing grid with the grid gap controlled at 10 mm. Fix the grids successively at the heights of 1 / 3, 1 / 2, and 2 / 3 from the bottom inside the 300 mL mixing container, and the included angle between adjacent grids is 60°; Step 3: Load the mixed raw materials into the mixing container, and the filling volume ratio of the materials is about 30%; Step 4: Fix the loaded mixing container on the vibrating table of the acoustic resonance mixing device, evacuate to 1 kPa, set the resonance frequency to 55 Hz, and set the resonance intensity to an acceleration of 1100 m / s 2 , and start the resonance mixing. Control the process temperature at 30 °C; Step 5: Collect the mixed materials in Step 4 from the container to complete the mixing process.

[0033] As Figure 5 shown, after the nano cobalt powder is deagglomerated in the tungsten carbide powder and detected by SEM, under the shearing effect introduced in the mixing container with the set parameters, the nano cobalt powder agglomeration can be deagglomerated to less than 3 μm.

[0034] Example 3 Step 1: In this example, the mixed raw materials are a mixed powder of magnesium oxide and niobium oxide. The average particle size of the magnesium oxide powder is 1 μm, the Carr index of the mixed powder is about 25, and the loose bulk volume of the weighed mixed raw materials is 105 mL in total; Step 2: Prepare a shearing grid with a grid gap controlled at 5 mm. Fix the grids successively at the heights of 1 / 3, 1 / 2, and 2 / 3 from the bottom inside a 150 mL mixing container, and the included angle between the directions of adjacent grids is 60°; Step 3: Load the mixed raw materials into the mixing container, and the filling volume ratio of the materials is about 70%; Step 4: Fix the filled mixing container on the vibrating table of the acoustic resonance mixing device, evacuate to 1 kPa, set the resonance frequency to 60 Hz, and set the resonance intensity to an acceleration of 800 m / s 2 , and start resonance mixing, with the process temperature controlled at 20 °C; Step 5: Collect the materials mixed in Step 4 from the container to complete the mixing process.

[0035] As Figure 6 shown, after the magnesium oxide powder is deagglomerated in the niobium oxide powder and detected by SEM, under the shearing effect introduced in the mixing container under the set parameters, the agglomeration of the magnesium oxide powder can be deagglomerated to 1 - 5 μm.

[0036] Comparative Example 1 In this comparative example, the acoustic resonance mixing technology is used to prepare the mixed powder of flake graphite and nano-carbon powder described in Example 1 as the mixed raw materials, and no grid is used for auxiliary shearing during the process. It mainly includes the following steps: Step 1: In this example, the mixed raw materials are the mixed powder of flake graphite and nano-carbon powder, and the Carr index of the powder is about 20. After weighing, the loose volume of the mixed raw materials is 250 mL in total; Step 2: Load the mixed raw materials into the mixing container, and the filling volume ratio of the materials is about 50%; Step 3: Fix the filled mixing container on the vibrating table of the acoustic resonance mixing device, evacuate to 1 kPa, set the resonance frequency to 70 Hz, and set the resonance intensity to an acceleration of 300 m / s 2 , and start resonance mixing, with the process temperature controlled at 25 °C; Step 4: Collect the materials mixed in Step 3 from the container to complete the mixing process.

[0037] As Figure 7 shown, after the nano-carbon powder is deagglomerated in the flake graphite powder and detected by SEM, under the same set parameters, when the shearing effect is not introduced in the mixing container, the agglomeration of the nano-carbon powder can only be deagglomerated to about 20 μm, and the deagglomeration effect is significantly inferior to that of Example 1.

[0038] As can be seen from the above, the high-viscosity powder acoustic resonance deagglomeration method with a composite adjustable shearing effect provided by the present invention designs a fixed shearing grid in the acoustic resonance mixing container. By adjusting the grid gap and the acoustic resonance mixing parameters, the high momentum of the material under the resonance state and the grid collide and shear each other, so as to achieve an adjustable shearing effect on the high-viscosity powder with a Carr index ≥ 20 during the acoustic resonance process, and achieve the purpose of deagglomerating the high-viscosity powder. The method provided by the present invention has simple processes and convenient operations, can avoid risks such as raw material contamination and excessive loss, and can be applied to high-viscosity powders that are difficult to achieve ball material screening.

[0039] The above description of the disclosed embodiments enables those skilled in the art to implement or use the present invention. Various modifications to these embodiments will be obvious to those skilled in the art, and the general principles defined herein can be implemented in other embodiments without departing from the spirit or scope of the present invention. Therefore, the present invention will not be limited to these embodiments shown herein, but will be accorded the widest scope consistent with the principles and novel features disclosed herein.

Claims

1. A method for high-viscosity powder acoustic resonance deagglomeration with a composite adjustable shearing effect, characterized in that, Fill the high-viscosity powder into an acoustic resonance mixing container internally installed with a grid, seal the acoustic resonance mixing container and fix it in an acoustic resonance device. After evacuating and setting corresponding process parameters, turn on the acoustic resonance device to deagglomerate the high-viscosity powder.

2. The deflocculation method according to claim 1, wherein The grid consists of a support and a shear edge. The shear edge is strip-shaped, and each shear edge is installed parallel to each other on the support to form a grid plane. The gap between adjacent shear edges is 3-10 mm; the shear edge is in the shape of a blade in the direction perpendicular to the grid plane.

3. The deflocculation method according to claim 2, characterized in that, The number of grids is ≥1 layer, and they are installed on the container wall at different heights from the bottom inside the acoustic resonance mixing container and are fixedly connected in contact with the container wall; the grid plane is parallel to the bottom surface of the acoustic resonance mixing container; in a top view, a direction angle is formed between the shear edges of adjacent layers of grids, and the direction angle includes a complementary small angle and a large angle.

4. The method for deflocculation according to claim 3, wherein The number of grids is 3 layers. The first-layer grid, the second-layer grid, and the third-layer grid are respectively installed on the container wall at 1 / 3, 1 / 2, and 2 / 3 heights from the bottom inside the acoustic resonance mixing container; in a top view, the small angle in the direction angle formed between the shear edges of adjacent layers of grids is 60°.

5. The deflocculation method according to claim 1, wherein The parameters of the acoustic resonance device are as follows: the resonance mixing frequency is 55.0 - 70.0 Hz, the resonance intensity is an acceleration of 300 - 1100 m / s 2 , and the temperature is 20 - 30 °C.

6. The deflocculation method according to claim 1, wherein The Carr index of the high-viscosity powder is ≥20.

7. The deflocculation method according to claim 1, characterized in that The volume ratio of the high-viscosity powder filled into the acoustic resonance mixing container is 30%-70%.

8. An acoustic resonance mixing container internally installed with a grid used in the deagglomeration method according to any one of claims 1-7.

9. An ultrafine powder prepared by using the deagglomeration method according to any one of claims 1-7.

10. An application of the ultrafine powder according to claim 8 in the preparation of new energy battery materials, the preparation of superhard materials, and powder metallurgy.

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