Method and equipment for improving fluidization state of powder

Abstract

The embodiment of the invention relates to a method and equipment for improving the fluidization state of powder. The method comprises the steps that the coverage area of airflow blown by a paddle is set, the rotating speed of the paddle in the fluidized sintering equipment is determined according to the coverage area, the paddle is an umbrella-shaped paddle, and the extending length of the paddle is correspondingly increased and decreased according to the rotating speed of the paddle; ultrasonic sources which are arranged in the fluidized sintering equipment and are distributed in a spatial three-dimensional manner are controlled to be started, so that ultrasonic waves generated by the ultrasonic sources which are arranged in a multi-angle and different-site manner generate superposition resonance in the fluidized sintering equipment; and the powder in the fluidized sintering equipment forms a fluidized state through rotation of the paddles, resonance of ultrasonic waves and mutual friction among powder particles. Through the combined action of mechanical dispersion of the paddles, ultrasonic resonance dispersion and self friction of powder under hot air flow, generation of caking materials in the sintering process of the powder can be effectively prevented, the high-degree fluidity and dispersity of the materials are improved, stirring is more uniform, and the qualified rate of products is increased.

Description

Technical Field

[0001] The present invention relates to the technical field of powder dispersion treatment, and particularly relates to a method and a device for improving the fluidization state of powder materials. Background Art

[0002] The fluidization of powder materials generally refers to solid fluidization, also known as pseudo-liquefaction. By the action of flowing fluid, a group of solid particles is suspended, so that the solid particles have some apparent characteristics of fluid. Using this contact method between fluid and solid to realize the operation of the production process is called fluidization technology. Fluidization technology is an operation that strengthens the interaction between fluid (gas or liquid) and solid particles. Granular solid materials are intermittently or continuously added into a vertical container, and the fluid is controlled to enter from the bottom at a certain speed so that its pressure drop is equal to or slightly greater than the weight of the solid particles per unit cross-section, and the solid particles move in a suspended state without being carried away by the fluid. During operation, the solid particle layer is like boiling liquid, so it is also called "fluidized bed". Since the particles of the working solid are relatively small and are in a state of violent movement under the action of the fluid, it is beneficial for the progress of many chemical reactions (such as roasting, catalysis, etc.) and many chemical processes (such as drying, adsorption, etc.).

[0003] However, during the sintering process of powder materials, continuous violent movement, large-scale mutual impact and friction absorb a large amount of mechanical energy or heat energy, and will generate a relatively high surface energy on the surface of the powder, making the particles in an extremely unstable state. In order to reduce the surface energy, the particles often reach a stable state by aggregating and approaching each other, and then there is a problem of large agglomeration and caking. This process is often not discovered until the sintering is completed, and may cause damage to equipment parts, resulting in a long maintenance cycle, affecting the product qualification rate and production capacity.

[0004] Based on this, we propose a method for improving the fluidization state of battery powder materials to solve the above problems. Summary of the Invention

[0005] The purpose of the present invention is to provide a method and a device for improving the fluidization state of powder materials, which can provide good powder fluidization effect and solve the problem of powder particle agglomeration and caking.

[0006] To this end, in the first aspect, an embodiment of the present invention provides a method for improving the fluidization state of powder materials, the method comprising:

[0007] Set the coverage area of the blowing air flow of the paddle, determine the rotation speed of the paddle in the fluidized sintering equipment according to the coverage area, and the paddle is an umbrella-shaped paddle, and the extension length of the paddle extends and shortens correspondingly according to the high or low rotation speed of the paddle;

[0008] Control the ultrasonic sources whose startup settings are spatially three-dimensionally distributed in the fluidized sintering device, so that the ultrasonic waves generated by the ultrasonic sources set at different positions from multiple angles are superimposed and resonated within the fluidized sintering device;

[0009] Through the rotation of the paddle blades, the resonance of the ultrasonic waves, and the mutual friction between the powder particles, the powder within the fluidized sintering device forms a fluidized state.

[0010] Preferably, before setting the coverage area of the blowing air flow of the paddle blades, the method further includes:

[0011] Determine the volume or stacking area of the powder to be fluidized through an image acquisition device, and set the coverage area of the blowing air flow of the paddle blades according to the volume or stacking area; or,

[0012] Determine the weight by weighing the powder to be fluidized, and set the coverage area of the blowing air flow of the paddle blades according to the weight.

[0013] Preferably, the ultrasonic sources are arranged in a ring shape on the inner wall of the fluidized sintering device, and there is a phase difference θ between the ultrasonic waves generated by adjacent ultrasonic sources, where 0° < θ < 180°.

[0014] Preferably, the radiation resonance coverage of the ultrasonic waves of each ultrasonic source is between 0 - 180°.

[0015] Preferably, the particle size of the powder is in the micron or nanometer range.

[0016] Preferably, the simple harmonic vibration of the ultrasonic waves is periodic and has a corresponding relationship with the rotation speed of the paddle blades.

[0017] Preferably, when the rotation speed of the paddle blades is less than the preset value, the phase difference 0° < θ < 90° between the ultrasonic waves generated by adjacent ultrasonic sources; when the rotation speed of the paddle blades is greater than or equal to the preset value, the phase difference 90° < θ < 180° between the ultrasonic waves generated by adjacent ultrasonic sources, where the preset value is 100 - 500 r / min.

[0018] Preferably, an inert atmosphere is maintained within the fluidized sintering device.

[0019] Preferably, the method further includes: performing heat treatment on the powder in the fluidized state, where the heat treatment temperature is 300°C - 1000°C and the heat preservation time is 0.5 - 5 h.

[0020] In a second aspect, an embodiment of the present invention provides a device for implementing the method for improving the fluidized state of powder described in the first aspect above. The device includes:

[0021] A fluidized sintering device cavity, paddle blades provided within the fluidized sintering device, and ultrasonic sources that are spatially three-dimensionally distributed within the fluidized sintering device;

[0022] Among them, the blade is an umbrella-shaped blade, which is arranged at the bottom of the cavity of the fluidized sintering equipment. The extended length of the blade extends and shortens correspondingly according to the rotation speed of the blade; the ultrasonic sources are arranged in a ring on the inner wall of the fluidized sintering equipment.

[0023] The method for improving the fluidization state of powder materials provided by the embodiment of the present invention can effectively prevent the generation of agglomerated materials during the sintering process through the combined action of mechanical dispersion of the blade, ultrasonic resonance dispersion, and friction of the powder materials themselves under hot air flow, increasing the high-degree fluidity and dispersion of the materials, making the stirring more uniform, and improving the qualified rate of products. Description of the Drawings

[0024] Figure 1 It is a flowchart of the method for improving the fluidization state of the negative electrode material powder of the battery provided by the embodiment of the present invention;

[0025] Figure 2 It is a schematic structural diagram of the blade provided by the embodiment of the present invention;

[0026] Figure 3 It is a schematic structural diagram of the ultrasonic sources arranged in a ring on the inner wall of the fluidized sintering equipment. Detailed Embodiments

[0027] The following will further describe the technical solutions of the present invention in detail through the drawings and embodiments.

[0028] The embodiment of the present invention provides a method for improving the fluidization state of the negative electrode material powder of the battery, which is applicable to fluidizing powders with a particle size of micrometers or nanometers. The main steps are as Figure 1 shown, including:

[0029] Step 110: Set the coverage area of the blowing air flow of the blade, determine the rotation speed of the blade in the fluidized sintering equipment according to the coverage area, and the blade is an umbrella-shaped blade, and the extended length of the blade extends and shortens correspondingly according to the rotation speed of the blade;

[0030] First, add the raw material powder into the fluidized sintering equipment through the feed port, and introduce an inert gas to remove the air in the equipment, so that the powder material will not be oxidized during the processing, and the oxygen content of the powder will not increase.

[0031] To set the coverage area of the blowing air flow of the blade, the volume or stacking area of the powder to be fluidized can be determined by the image acquisition device arranged in the fluidized sintering equipment, and then automatically calculated and set according to the volume or stacking area. Of course, it can also be set manually, or the weight of the powder to be fluidized can be determined by weighing, and automatically calculated and set or manually set according to the weight.

[0032] The blade is an umbrella-type blade with an umbrella-like structure. As shown in Figure 2 , it is installed at the bottom of the fluidized sintering equipment. By changing the rotational speed, the center of gravity of the blade changes accordingly, thereby changing the extended length of the blade. The higher the rotational speed, the higher the center of gravity of the blade, the more open the umbrella-like structure, and the larger the coverage area of the blade. Conversely, the lower the rotational speed, the lower the center of gravity of the blade, the more closed the umbrella-like structure, and the smaller the coverage area of the blade. The airflow agitation is carried out by adjusting the rotational speed of the blade to control the dispersion state of the powder material. When the blade is rotating at a high speed for agitation, the coverage area of the blade becomes larger, and the material will be introduced from the edge during the flow process and gather towards the center of the equipment main body, and the strength in the middle will increase; when the blade rotates at a low speed, the flow of the material becomes relatively slower, and the strength at the edge becomes relatively larger at this time.

[0033] Step 120: Control the ultrasonic sources arranged in a three-dimensional space in the fluidized sintering equipment to start, so that the ultrasonic waves generated by the ultrasonic sources set at different positions from multiple angles are superimposed and resonate in the fluidized sintering equipment;

[0034] Among them, the ultrasonic sources are arranged in a ring on the inner wall of the fluidized sintering equipment, and there is a phase difference θ between the ultrasonic waves generated by adjacent ultrasonic sources, where 0° < θ < 180°, as shown in Figure 3 . In addition, the radiation resonance coverage area of the ultrasonic wave of each ultrasonic source is between 0 - 180°. The radiation resonance coverage area refers to the area where the resonance frequency of the ultrasonic wave matches the acoustic wave frequency in the surrounding medium during the radiation process. When the frequency of the ultrasonic wave source matches the sound speed and density of the surrounding medium, a resonance phenomenon will occur, making the ultrasonic wave strengthened in a specific area to form a resonance coverage area.

[0035] Preferably, the simple harmonic vibration of the ultrasonic wave is periodic and has a corresponding relationship with the rotational speed of the blade. Preferably, when the rotational speed of the blade is less than the preset value, that is, in the low-speed rotation state, the phase difference between the ultrasonic waves generated by adjacent ultrasonic sources is 0° < θ < 90°; when the rotational speed of the blade is greater than or equal to the preset value, that is, in the high-speed rotation state, the phase difference between the ultrasonic waves generated by adjacent ultrasonic sources is 90° < θ < 180°, where the preset value is 100 - 500 r / min.

[0036] The resonance of the ultrasonic wave of the present invention is generated by ultrasonic sources in multiple directions, among which the sound energy density is adjustable and the angle is adjustable.

[0037] Step 130: Perform heat treatment on the powder material in the fluidized state, where the heat treatment temperature is 300°C - 1000°C and the heat preservation time is 0.5 - 5 h.

[0038] The present invention preferably uses a vertical gas-phase reaction sintering equipment as the closed fluidized sintering equipment to facilitate the better flow of the powder material.

[0039] During the above process, an inert atmosphere is maintained inside the fluidized sintering equipment. The rotation of the paddle blades, the resonance of ultrasonic waves, and the mutual friction between the powder particles cause the powder inside the fluidized sintering equipment to form a fluidized state.

[0040] In summary, the present invention improves the fluidized state of the powder material by introducing ultrasonic wave generating sources at different positions from multiple angles and a new type of umbrella-shaped stirring paddle blade to reduce the problem of difficult dispersion due to agglomeration and caking. While performing air stirring on the powder (such as the powder particles of the battery negative electrode material) added to the closed fluidized sintering equipment and cooperating with ultrasonic oscillation, the powder particles in the closed fluidized sintering equipment start to flow and form a "fluidized" state. The powder particles not only obtain kinetic energy and are dispersed through the air flow, but also weaken the mutual surface interaction energy between the powder particles through the ultrasonic resonance effect, which can fully break up the powder accumulation on the inner wall of the equipment, enable the powder particles to participate in the gas-solid mixing again, reduce the agglomeration of the powder particles and fully disperse them to form a fluidized state, so as to improve the fluidized state of the composite negative electrode material powder particles.

[0041] On the one hand, the ultrasonic resonance effect at different positions from multiple angles drives the materials introduced into the main body of the fluidized sintering equipment to oscillate under the resonance effect, making the materials in a highly dispersed state. Ultrasonic dispersion utilizes the local high temperature, high pressure, strong shock waves, and microjets generated during ultrasonic cavitation to significantly weaken the nano interaction energy between nano particles, effectively preventing the agglomeration of nano particles and enabling them to be fully dispersed. The pulsed flow generated by the superposition of ultrasonic waves increases the mixing rate of the particles, breaks the liquid bridge between the solid particles, and prevents the particles from caking and agglomerating.

[0042] On the other hand, an umbrella-shaped adjustable mechanical paddle blade is used at the bottom of the equipment to make the materials accumulated at the bottom during the sintering process due to low dispersibility flow better. The pressure difference formed by the rotation of the paddle blade makes the materials fit better with the flow of the flow field. By adjusting the rotation speed of the paddle blade, the dispersion state of the materials can be regulated. When the paddle blade rotates at a high speed for stirring, the coverage area of the paddle blade becomes larger, and the materials will be introduced from the edge and gathered towards the center of the main body of the equipment during the flow process, and the intensity in the middle will increase; when the paddle blade rotates at a low speed, the flow of the materials slows down relatively, and at this time the intensity at the edge becomes relatively larger. The periodic change of the two speeds avoids the phenomenon that too strong ultrasonic waves cause fine particles to tend to aggregate together to form agglomerated secondary particles or even tertiary particles, and realizes the uniform stirring and dispersion of the materials during the sintering process.

[0043] Through the method of the present invention, the generation of caked materials during the sintering of the powder can be effectively prevented, the high-degree fluidity and dispersibility of the materials are increased, the stirring is made more uniform, and the qualified rate of the product is improved.

[0044] The device for implementing the above method includes: a fluidized sintering device cavity, paddle blades arranged in the fluidized sintering device, and ultrasonic sources distributed in a three-dimensional space within the fluidized sintering device; among them, the paddle blades are umbrella-shaped paddle blades arranged at the bottom of the cavity of the fluidized sintering device, and the protruding length of the paddle blades extends and shortens correspondingly according to the rotational speed of the paddle blades; the ultrasonic sources are arranged in a ring on the inner wall of the fluidized sintering device.

[0045] This device can be used for powder dispersion, such as the dispersion of powder particles of battery anode materials, and specifically may include: any one of metal material powder particles, non-metal material powder particles, or composite material powder particles. In practical applications, it is necessary to select appropriate rotational speeds, ultrasonic source control parameters, sintering temperatures, times, etc. according to specific applications and material characteristics to obtain the desired effects.

[0046] To more clearly illustrate the purpose and advantages of the present invention, the present invention will be further elaborated below in conjunction with embodiments. In addition, the embodiments described in the present invention are only partial embodiments. All other embodiments obtained by those skilled in the art without creative efforts based on the embodiments described in the present invention fall within the protection scope of the present invention. Additionally, it should be understood that these embodiments are only for more detailed description and should not be construed as limiting the present invention in any form, that is, it is not intended to limit the protection scope of the present invention.

[0047] Embodiment 1

[0048] This embodiment provides a method for improving the fluidized state of battery anode material powder, and the specific preparation process is as follows.

[0049] 1) At room temperature, put the micron-scale carbon-based powder material into a closed container through the feed port, maintain a nitrogen atmosphere, turn on the motor, adjust the rotational speed to 50 r / min, and perform gas stirring on the micron-scale carbon-based powder material.

[0050] 2) When the micron-scale carbon-based powder material starts to flow in suspension or oscillation in the device, start the ultrasonic source, adjust the phase difference θ between adjacent ultrasonic sources to 120°, and the micron-scale carbon-based powder material forms a fluidized state under the combined action of gas flow and ultrasonic resonance. Heat it to 300 °C at a rate of 5 °C / min, keep it at a constant temperature for 1 h, and then cool and discharge.

[0051] Embodiment 2

[0052] This embodiment provides a method for improving the fluidized state of battery anode material powder, and the specific preparation process is as follows.

[0053] 1) At room temperature, put the nano-silicon-based powder material into a closed container through the feed port, maintain a nitrogen atmosphere, turn on the motor, and adjust the rotational speed to 50 r / min to perform gas stirring on the nano-silicon powder material.

[0054] 2) When the nano-silicon-based powder material is suspended or oscillating in the equipment, start the ultrasonic source and adjust the phase difference θ between adjacent ultrasonic sources to 120°. The nano-silicon powder material forms a fluidized state under the combined action of air flow and ultrasonic resonance, is heated to 800 °C at a rate of 5 °C / min, kept at a constant temperature for 1 h, and then cooled and discharged.

[0055] Example 3

[0056] This example provides a method for improving the fluidized state of the battery anode material powder, and the specific preparation process is as follows.

[0057] 1) At room temperature, put the ultra-fine metal powder material into a closed container through the feed port, keep a nitrogen atmosphere, start the motor, and adjust the rotation speed to 100 r / min to carry out air flow stirring on the ultra-fine metal powder material.

[0058] 2) When the ultra-fine metal powder material is suspended or oscillating in the equipment, start the ultrasonic source and adjust the phase difference θ between adjacent ultrasonic sources to 150°. The ultra-fine metal powder material forms a fluidized state under the combined action of air flow and ultrasonic resonance, is heated to 800 °C at a rate of 5 °C / min, kept at a constant temperature for 1 h, and then cooled and discharged.

[0059] Example 4

[0060] This example provides a method for improving the fluidized state of the battery anode material powder, and the specific preparation process is as follows.

[0061] 1) At room temperature, put the silicon-carbon composite powder material into a closed container through the feed port, keep a nitrogen atmosphere, start the motor, and adjust the rotation speed to 50 r / min to carry out air flow stirring on the silicon-carbon composite powder material.

[0062] 2) When the silicon-carbon composite powder material is suspended or oscillating in the equipment, start the ultrasonic source and adjust the phase difference θ between adjacent ultrasonic sources to 120°. The silicon-carbon composite powder material forms a fluidized state under the combined action of air flow and ultrasonic resonance, is heated to 900 °C at a rate of 5 °C / min, kept at a constant temperature for 3 h, and then cooled and discharged.

[0063] Example 5

[0064] This example provides a method for improving the fluidized state of the battery anode material powder, and the specific preparation process is as follows.

[0065] 1) At room temperature, put the silicon-carbon composite powder material into a closed container through the feed port, keep a nitrogen atmosphere, start the motor, and adjust the rotation speed to 200 r / min to carry out air flow stirring on the silicon-carbon composite powder material.

[0066] 2) When the silicon-carbon composite powder material is suspended or oscillating and flowing in the equipment, start the ultrasonic source, adjust the phase difference θ between adjacent ultrasonic sources to 30°, and the silicon-carbon composite powder material forms a fluidized state under the combined action of air flow and ultrasonic resonance. Heat it to 900°C at a rate of 5°C / min, keep it at a constant temperature for 3 hours, and then cool and discharge the material.

[0067] The method for improving the fluidized state of the powder provided by the embodiment of the present invention can effectively prevent the formation of agglomerated materials during the sintering process of the powder through the combined action of the mechanical dispersion of the paddle blades, ultrasonic resonance dispersion, and the self-friction of the powder under the hot air flow, increasing the high-degree fluidity and dispersibility of the material, making the stirring more uniform, and improving the qualified rate of the product.

[0068] Those skilled in the art should also be able to further realize that the units and algorithm steps of each example described in combination with the embodiments disclosed in this article can be implemented by electronic hardware, computer software, or a combination of the two. To clearly illustrate the interchangeability of hardware and software, the composition and steps of each example have been generally described according to functions in the above description. Whether these functions are executed in a hardware or software manner depends on the specific application and design constraints of the technical solution. Those skilled in the art can use different methods to implement the described functions for each specific application, but such implementation should not be considered to exceed the scope of the present invention.

[0069] The steps of the method or algorithm described in combination with the embodiments disclosed in this article can be implemented by hardware, software modules executed by a processor, or a combination of the two. The software modules can be placed in a random access memory (RAM), internal memory, read-only memory (ROM), electrically programmable ROM, electrically erasable programmable ROM, registers, hard disk, removable disk, CD-ROM, or any other form of storage medium well-known in the technical field.

[0070] The specific embodiments described above have further elaborated on the purpose, technical solution, and beneficial effects of the present invention. It should be understood that the above description is only the specific embodiments of the present invention and is not used to limit the protection scope of the present invention. Any modifications, equivalent replacements, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for improving the fluidization state of powder materials, characterized in that, The method includes: Setting the coverage area of the airflow blown by the paddle, determining the rotation speed of the paddle in the fluidized sintering equipment according to the coverage area, and the paddle is an umbrella-shaped paddle, and the extension length of the paddle extends and shortens correspondingly according to the high or low rotation speed of the paddle; Controlling to start the ultrasonic sources arranged in a three-dimensional space in the fluidized sintering equipment, so that the ultrasonic waves generated by the ultrasonic sources arranged at different positions from multiple angles are superimposed and resonated in the fluidized sintering equipment; Making the powder in the fluidized sintering equipment form a fluidized state through the rotation of the paddle, the resonance of the ultrasonic waves, and the mutual friction between the powder particles.

2. The method according to claim 1, characterized in that, Before setting the coverage area of the airflow blown by the paddle, the method further includes: Determining the volume or stacking area of the powder to be fluidized through an image acquisition device, and setting the coverage area of the airflow blown by the paddle according to the volume or stacking area; or, Determining the weight by weighing the powder to be fluidized, and setting the coverage area of the airflow blown by the paddle according to the weight.

3. The method according to claim 1, characterized in that, The ultrasonic sources are arranged in a ring on the inner wall of the fluidized sintering equipment, and there is a phase difference θ between the ultrasonic waves generated by adjacent ultrasonic sources, where 0° < θ < 180°.

4. The method according to claim 1, characterized in that, The radiation resonance coverage of the ultrasonic wave of each ultrasonic source is between 0 - 180°.

5. The method according to claim 1, characterized in that, The particle size of the powder is in the micron or nanometer range.

6. The method according to claim 1, characterized in that, The simple harmonic vibration of the ultrasonic wave is periodic and has a corresponding relationship with the rotation speed of the paddle.

7. The method according to claim 1, characterized in that, When the rotation speed of the paddle is less than the preset value, the phase difference between the ultrasonic waves generated by adjacent ultrasonic sources is 0° < θ < 90°; when the rotation speed of the paddle is greater than or equal to the preset value, the phase difference between the ultrasonic waves generated by adjacent ultrasonic sources is 90° < θ < 180°, where the preset value is 100 - 500 r / min.

8. The method according to claim 1, characterized in that, An inert atmosphere is maintained in the fluidized sintering equipment.

9. The method according to claim 1, characterized in that, The method further includes: heat-treating the powder in the fluidized state, the heat-treatment temperature is 300°C - 1000°C, and the heat-preservation time is 0.5 - 5 h.

10. An apparatus for performing the method for improving the fluidization state of powder materials according to any one of claims 1-9, characterized in that, The equipment includes: A fluidized sintering equipment cavity, a paddle arranged in the fluidized sintering equipment, and ultrasonic sources arranged in a three-dimensional space in the fluidized sintering equipment; Among them, the paddle is an umbrella-shaped paddle, arranged at the bottom of the cavity of the fluidized sintering equipment, and the extension length of the paddle extends and shortens correspondingly according to the high or low rotation speed of the paddle; the ultrasonic sources are arranged in a ring on the inner wall of the fluidized sintering equipment.

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