Aerogel micro-powder grinding, floating and grading integrated preparation system and method

Abstract

This invention relates to the field of aerogel processing technology, and discloses an integrated preparation system and method for aerogel micropowder grinding, floating, and classification. The system includes: S1, initial crushing using a composite crushing method of low-speed shearing and air-assisted grinding; S2, constructing a composite force field of axial upward airflow and radial rotating circulation, utilizing the gravity-buoyancy difference to cause fine particles to float to the fine sieving area of ​​the screen, while coarse particles settle to the coarse particle return area at the bottom of the chamber; S3, transporting the coarse particles in the return area back to the air-assisted large-piece crushing area for secondary crushing via a return mechanism; and S4, real-time acquisition of particle size distribution and fine powder concentration data through online particle size monitoring, constructing a closed-loop control logic. This application precisely adapts to the material properties of aerogel, achieving coordinated operation of crushing, sorting, and re-grinding through an integrated structure and closed-loop intelligent control, possessing multiple advantages such as high precision, high yield, high efficiency, low cost, and environmental friendliness.

Description

Technical Field

[0001] This invention relates to the field of aerogel processing technology, specifically to an integrated preparation system and method for grinding, floating and classifying aerogel micropowder. Background Technology

[0002] Aerogels, as nanoporous lightweight materials, possess ultra-low density, high specific surface area, and excellent thermal insulation properties, making them widely used in thermal insulation, aerospace, energy conservation and environmental protection, and catalyst carriers. The particle size distribution of aerogel micropowder directly determines its dispersibility, formability, thermal insulation performance, and overall effectiveness. Precise control of the acceptable particle size range is crucial; excessively coarse particles affect dispersion uniformity, while excessively fine particles easily agglomerate, damage the porous framework, reduce thermal insulation efficiency, and also lead to raw material waste.

[0003] Current aerogel micropowder preparation processes generally employ a segmented process of grinding followed by sieving, but this approach has several limitations. First, the grinding process is an open-loop crushing process without real-time classification intervention, resulting in uncontrolled particle size precision and an inability to adjust the ratio of coarse to fine particles as needed. Second, traditional vibrating sieving and drum sieving rely on screens for retention and classification; aerogels have extremely low density and are easily dispersed, readily adhering to and clogging the screens, leading to low classification efficiency and poor precision, with an ideal product yield of only below 60%. Third, coarse particles require subsequent screening and re-grinding by operators, and excessive fine particles cannot be recovered, resulting in cumbersome procedures, high labor costs, raw material losses, and low overall output. Fourth, grinding and sieving are independent processes, unable to be linked and controlled, ensuring a constant grinding intensity. Fifth, aerogel micropowder generates significant dust, polluting the production environment, causing material loss, and further increasing production costs. Summary of the Invention

[0004] The present invention aims to provide an integrated preparation system and method for grinding, floating and classifying aerogel micropowder, which solves the problems of difficult particle size control, easy clogging of the classification screen, serious over-grinding, low qualified yield, inability to link grinding and classification, easy dust pollution and high production efficiency and low cost in the existing aerogel micropowder production process.

[0005] To achieve the above objectives, the present invention adopts the following technical solution: an integrated preparation method for aerogel micropowder grinding, floating, and classification, comprising the following steps: S1, the large aerogel material to be processed is placed into the air-assisted large-piece crushing zone of the closed vertical integrated cavity through a one-way sealed feeding structure, and the preliminary crushing process is carried out by a composite crushing method of low-speed shearing and air-assisted crushing. S2, a composite force field of axial upward airflow and radial rotational circulation is constructed in the cavity to form the first screening. The gravity-buoyancy difference formed by the difference in size and mass of aerogel particles is used to achieve dynamic floating stratification, so that fine particles float to the fine screening area of ​​the screen with the airflow, and coarse particles settle to the coarse particle return area at the bottom of the cavity. S3 automatically transports coarse particles in the reflux zone to the air-assisted large-piece crushing zone for secondary crushing through the reflux mechanism, and performs fixed-mesh precise grading on fine particles that float to the fine screening zone. S4 collects real-time data on particle size distribution and fine powder concentration through online particle size monitoring, constructs closed-loop control logic, and adjusts crushing intensity, airflow speed and pressure, coarse particle return flow and screen parameters in reverse to adjust the ratio of coarse and fine particles, and continuously completes the crushing, sorting, grinding and fine screening cycle.

[0006] Meanwhile, this solution also provides an integrated preparation system for aerogel micropowder grinding, floating, and classification, applied to the aforementioned integrated preparation method for aerogel micropowder grinding, floating, and classification. The system includes a sealed vertical integrated cavity, which is divided from top to bottom into a finished product collection area, a fine sieving area, a dynamic floating sorting area, a qualified particle buffer area, an air-assisted large particle crushing area, and a coarse particle recirculation area; there are no rigid partitions between the areas; the finished product collection area is equipped with at least two independent sealed collection tanks for collecting aerogel micropowder of different particle sizes; and the cavity contains... The system includes a unidirectional anti-spray feeding mechanism, a dynamic floating sorting mechanism, a coarse particle return mechanism, an air-assisted large particle crushing mechanism, and an online monitoring module. The dynamic floating sorting mechanism comprises a variable frequency fan and radial circulation guide vanes. The variable frequency fan is located outside the cavity, and the radial circulation guide vanes are arranged in the dynamic floating sorting zone. The coarse particle return mechanism is located at the bottom of the cavity, with its input end connected to the coarse particle return zone and its output end connected to the air-assisted large particle crushing zone. The air-assisted large particle crushing mechanism is located within the air-assisted large particle crushing zone. The online monitoring module is located within the dynamic floating sorting zone.

[0007] The principles and advantages of this scheme are: The core technical contradiction in the current field of aerogel micropowder preparation is the contradiction between the controllability of the proportion of qualified-sized blocks and production efficiency during the grinding of large aerogel blocks: the essence of aerogel grinding is to crush large blocks into smaller blocks of different sizes, and all blocks are irregular in shape; however, existing crushing technology can only achieve the basic function of "turning large blocks into smaller blocks", and lacks a mechanism for adjusting the proportion of different blocks. After crushing, it is easy to have an imbalance in the proportion of too many small blocks or too many large blocks. Since both sizes are effective products, the proportion cannot be adjusted by discarding by-products. The proportion can only be corrected by multiple crushing and graded rework, which leads to a significant increase in production frequency, low production efficiency, and high labor and time costs.

[0008] The fundamental reason why this contradiction is difficult to resolve is that existing technologies have always designed the crushing and grading processes separately, failing to construct a collaborative closed loop of "crushing-grading-recirculation-control". This makes it impossible to efficiently recirculate and re-crush coarse-sized blocks with imbalanced proportions, and also lacks real-time monitoring and dynamic control methods. It is impossible to achieve the preset proportions in one crushing operation from the root cause, and can only passively deal with the rework problem after the proportions become unbalanced, thus falling into a vicious cycle of "proportion imbalance-multiple rework-low efficiency".

[0009] This solution addresses the aforementioned contradictions, with "precise proportional control and reduced production frequency" as its core objective. It constructs a sealed, vertical, integrated cavity that integrates, from top to bottom, a finished product collection area, a fine screening area, a dynamic floating sorting area, a qualified particle buffer area, an air-assisted large-piece crushing area, and a coarse particle return area. It is equipped with core mechanisms such as unidirectional anti-spray feeding, air-assisted large-piece crushing, composite force field floating sorting, coarse particle return, online monitoring, and closed-loop control, forming a complete closed-loop process of "crushing-grading-returning-control".

[0010] First, large aerogel blocks are broken down into smaller blocks of varying sizes using air-assisted crushing. These smaller blocks are then subjected to coarse grading via a composite force field flotation system and fine grading via a screen, achieving precise separation of coarse and fine qualified particles. Simultaneously, the disproportionately large blocks are temporarily stored in a buffer area and then precisely returned to the crushing zone for secondary crushing via a variable-frequency spiral reflux mechanism. Combined with online particle size monitoring and PID closed-loop control, the reflux speed and crushing parameters are dynamically adjusted to precisely control the output ratio of coarse and fine qualified particles, ensuring the ratio deviation remains stable within ±10%. The core of this solution lies in overcoming the design limitations of existing technologies that separate crushing and grading processes. It deeply integrates ratio control into the entire crushing process, achieving proactive ratio control through secondary crushing via coarse particle reflux, rather than passive rework. This design logic eliminates the root cause of multiple rework due to ratio imbalance.

[0011] This solution offers several advantages. First, it achieves precise control over the proportion of qualified-sized blocks, completely resolving the pain point of imbalanced proportions in existing technologies. A single crushing operation yields qualified products with a preset proportion, significantly reducing production frequency, improving production efficiency, and lowering production costs. Second, coarse-sized blocks are 100% recycled through secondary crushing, increasing material utilization to over 99% and preventing waste. Third, it ensures strong production continuity by employing composite force field grading and triple anti-blocking measures to avoid production interruptions caused by mesh blockage and adhesion, achieving continuous and stable production. Fourth, it boasts outstanding environmental friendliness and adaptability. The fully enclosed design prevents fine powder leakage, achieving a fine powder recovery rate of over 99.5%. It is also specifically adapted to hydrophilic and hydrophobic aerogels to meet the production needs of different materials. Fifth, it features a high degree of automation. Online monitoring and closed-loop control enable fully automated operation without manual intervention, ensuring stable and reliable operation. This provides a novel technical solution for the large-scale, efficient production of aerogel micropowder, demonstrating significant technological advancement and industrial application value. Attached Figure Description

[0012] Figure 1 This is a schematic flowchart of an integrated preparation method for grinding, floating, and classifying aerogel micropowder according to the present invention.

[0013] Figure 2 This is a structural block diagram of an integrated preparation system for grinding, floating, and classifying aerogel micropowder according to the present invention.

[0014] The markings in the accompanying drawings include: 1. Cavity; 2. Finished product collection area; 3. Fine screening area; 4. Dynamic floating sorting area; 5. Qualified particle buffer area; 6. Air-assisted large particle crushing area; 7. Coarse particle return area; 8. Discharge pipe; 9. Radial circulation guide plate; 10. Closed-loop control cabinet; 11. Online monitoring module; 12. Sealed collection tank; 13. Feed end; 14. First-stage screen; 15. Second-stage screen. Detailed Implementation

[0015] The following detailed description illustrates the specific implementation method: This embodiment presents an integrated preparation system and method for grinding, floating, and classifying aerogel micropowder. Based on the inherent characteristics of aerogel—low density, lightweight flotation, easy aggregation, and porous and easily damaged—it abandons the traditional segmented process. Through low-speed shear crushing, coarse classification using a composite force field, fine sieving using a fixed-mesh sieve, coarse particle reflux circulation, and online proportional closed-loop control, it achieves continuous preparation with a fully closed and real-time controlled process. This solves the problems of particle size loss, low yield, clogging, and high cost associated with traditional processes.

[0016] Option 1 A method for the integrated preparation of aerogel micropowder through grinding, floating, and classification is provided, as shown in the attached figure. Figure 1 As shown, it includes the following steps: S1, the aerogel material to be processed is placed in the air-assisted large-block crushing zone 6 of the sealed vertical integrated cavity, and crushed by low-speed shearing and air-assisted crushing. The air-assisted crushing is to introduce a small amount of dry inert protective gas into the grinding chamber to form an air cushion layer that reduces hard contact wear of particles. The large aerogel is broken into small blocks without damaging the porous skeleton of the aerogel.

[0017] In this embodiment, the dustproof sealing cover at the top of the feed hopper is opened, and large pieces of aerogel material are placed into the feed hopper. The dustproof cover is then closed to form a preliminary seal. The one-way flow guide valve is activated, allowing material to enter the gas-assisted large-piece crushing zone 6 only from top to bottom through the sealed feed pipe, blocking the reverse splashing path of airflow and fine powder within the crushing chamber. In this embodiment, fluororubber sealing gaskets are installed at the connections between the sealed feed pipe, the one-way flow guide valve, and the crushing chamber. A low dew point dry inert gas (nitrogen, dew point ≤ -40℃) is introduced into the feed pipe to maintain a slight positive pressure (0.02MPa) within the pipe, forming a one-way airflow barrier to prevent fine powder generated during the crushing process from being carried away by the airflow and overflowing from the feed inlet.

[0018] Based on the basic parameters of the material to be crushed (material characteristic size, bulk density, hydrophilic / hydrophobic type, initial porosity), the core operating parameters of the crushing zone are preset and activated. Low-speed shearing and air-assisted crushing are used to crush the material, breaking large pieces of aerogel into aerogel blocks of different sizes.

[0019] In this embodiment, the traditional high-pressure extrusion and high-impact grinding methods are abandoned, and the method is specifically designed for low-density aerogels (density only 3-50 kg / m³). 3 Due to its core characteristics of being brittle and having a porous nanostructure prone to collapse, the aerogel is initially crushed using a low-speed shearing combined with air-assisted crushing. Specifically, a low-speed, small-gap design is employed, with the grinding rotor using a wear-resistant ceramic rotor-stator pairing structure. The rotor-stator gap is adjusted to 15mm to avoid excessive shearing leading to micronization. The rotor speed is controlled at 150-200 r / min, using a low-speed shearing method to break down only large aerogel blocks, far below the 3000 r / min or higher speeds of conventional grinding equipment. Large aerogel blocks are broken down through the weak impact and shearing action of the rotor blades, without applying vertical crushing force, thus preserving the porous framework within the aerogel particles.

[0020] Simultaneously, a small amount of dry, inert protective gas is introduced into the bottom of the grinding chamber through an annular air passage to form an air cushion layer that reduces hard contact wear between particles, while preventing aerogel blocks from adhering to the inner wall of chamber 1. In this embodiment, the inert protective gas is nitrogen or dry air, with the inlet pressure controlled at 0.15-0.2 MPa and the inlet flow rate at 0.1-0.5 m³ / s. 3The air intake pressure is adjusted in conjunction with the crushing speed. That is, for every 100 r / min increase in speed, the air intake volume increases by 5%-8% simultaneously. The thickness and rigidity of the air cushion layer are adaptively enhanced to maintain an effective buffering and lifting effect, ensuring that no hard contact occurs under different working conditions.

[0021] Because aerogel has an extremely low density, even minute gas dynamic pressure can locally lift and suspend the particles, transforming the traditional solid-solid hard contact into a solid-gas-solid soft contact. This eliminates hard contact, strong compression, and strong friction between the particles and metal / ceramic components, significantly reducing collision and compression stress. This creates a uniform and stable air cushion layer between the rotor and stator, and between the particles and the inner wall of cavity 1, keeping the aerogel particles in a semi-suspended grinding state. Simultaneously, it prevents aerogel clumps from adhering to the inner wall of cavity 1, greatly reducing hard contact wear and frictional heat generation between particles and hard components, and preventing the breakage of the nanoporous framework. The rotor blades rotate at a preset speed, breaking down large aerogel clumps through shearing force. Combined with the low-impact characteristics of low-speed shearing, large aerogel clumps are broken into aerogel clumps of different sizes, eliminating reliance on strong mechanical force for breakage and further reducing the generation of excessively fine particles, thus controlling the ratio of coarse to fine particles.

[0022] In this embodiment, during the crushing process, the temperature of the crushing chamber is controlled below 80°C in real time to avoid high temperature damage to the porous skeleton structure of the aerogel. The separated aerogel blocks are propelled from bottom to top by the air-assisted airflow and enter the dynamic floating sorting zone 4 to participate in the subsequent coarse classification by the composite force field.

[0023] S2, a composite force field of axial upward airflow and radial rotational circulation is constructed in the cavity 1 to form the first screening. The gravity-buoyancy difference formed by the difference in size and mass of aerogel particles is used to achieve dynamic floating stratification, so that fine particles float to the fine screening area 3 of the screen with the airflow, and coarse particles settle to the coarse particle return area 7 at the bottom of the cavity 1.

[0024] In this embodiment, the aerogel blocks, after being subjected to S1 air-assisted large-scale crushing, are introduced into the dynamic floating sorting zone 4. Utilizing the difference in particle size between aerogel particles and buoyancy, gravity, and centrifugal force, a composite force field of axial airflow stratification and radial circulation dispersion is constructed in the floating sorting zone. Specifically, air is supplied by a variable frequency fan on the outer side of the bottom of the cavity 1. The airflow enters the junction between the crushing and sorting zones through a sealed air duct, and a controllable airflow is delivered upwards from the bottom of the cavity 1. This airflow generates an upward drag force (buoyancy component) on the particles. Due to the extremely low density of the aerogel particles, the balance between their gravity and the airflow drag force is highly dependent on particle size; that is, fine particles, with their small mass, experience a greater airflow drag force than gravity, and thus float upwards with the airflow into the fine screening zone 3. Coarse particles settle to the coarse particle return zone 7 at the bottom of the cavity 1. Simultaneously, a dry, slightly positive pressure environment is maintained within the cavity 1 through a closed-loop circulation of dry inert gas, suitable for hydrophilic aerogels.

[0025] In this embodiment, the airflow parameters for dynamic floating stratification are as follows: the axial upward airflow velocity is controlled at 0.8-1.5 m / s, preferably 1.2 m / s; the air pressure is maintained at 500-2000 Pa and adjusted in real time according to the target qualified particle size. The airflow parameters are adapted to different target qualified particle sizes by frequency conversion control. The airflow medium uses a low dew point dry inert gas (dew point ≤ -40℃) to maintain a slight positive pressure (0.01-0.02 MPa) in cavity 1. This provides power for the floating of the block and prevents the intrusion of external humid air from causing the hydrophilic aerogel to absorb moisture and agglomerate.

[0026] While axial airflow alone can achieve initial stratification, it is prone to problems such as particle agglomeration, fine powder enveloping coarse particles, and unstable stratification interfaces. Therefore, in this embodiment, a radial circulation guide vane 9 is designed in the sorting zone, with its rotation speed controlled at 100-300 r / min. This creates a tangential rotating flow field in the sorting zone, subjecting the particles to both centrifugal force and turbulent disturbance, resulting in radial circulation and dispersion. Centrifugal force causes secondary separation of particles of different sizes along the radial direction, further enhancing particle size sorting accuracy. The rotational disturbance exerts a shearing and peeling effect on the aerogel agglomerates, releasing the fine powder enveloping the surface of coarse particles, dispersing the aerogel particle agglomerates, and preventing fine particles from enveloping coarse particles, thus avoiding sorting distortion and forming a stable air-floating sorting layer to ensure stratification accuracy. Furthermore, the circulation guides the axially rising airflow to rotate along the inner wall of the cavity 1, forming a stable rotating circulation that provides centrifugal force support for the stratification of coarse and fine particles.

[0027] Axial airflow is responsible for vertical coarse and fine separation, while radial circulation is responsible for radial purification and agglomeration dispersal. The two are coupled to form a self-stabilizing, adaptive, dynamic equivalent screen. In this embodiment, fine particles with a size of 3-5 mm are subjected to airflow drag and buoyancy greater than their own weight and centrifugal force. Lifted by the axial upward airflow, they overcome the centrifugal resistance of the radial circulation, pass upward through the dynamic floating separation zone 4, and enter the upper screen fine sieving zone 3 to participate in subsequent precise sieving. Coarse particles with a size of 5-8 mm are subjected to centrifugal force greater than airflow drag and buoyancy. Under the centrifugal action of the radial circulation, they are thrown towards the inner wall of the cavity 1, while falling along the inner wall under their own gravity, and finally sinking to the qualified particle buffer zone 5 at the bottom of the cavity 1, waiting for the backflow crushing and proportion control in S3. Because of the ultra-low density, mass, and easy suspension characteristics of aerogel, it can exhibit a significant particle size-floating velocity correlation even under weak airflow. Ordinary high-density mineral powders cannot achieve such sensitive airflow stratification.

[0028] In this embodiment, based on the material type (hydrophilic / hydrophobic) and real-time operating data collected by S1, the composite force field parameters are finely adjusted to ensure stratification efficiency and stability.

[0029] For hydrophilic aerogels, the axial airflow velocity should be appropriately increased to 1.3-1.5 m / s, and the tilt angle of the guide vanes should be increased to 25°±5° to enhance the airflow lifting force, prevent fine particles from settling due to moisture absorption and aggregation, and maintain a slight positive pressure in the dry air path to inhibit moisture absorption.

[0030] For hydrophobic aerogels, maintain an axial airflow velocity of 0.8-1.1 m / s and a guide vane tilt angle of 15°±5° to reduce airflow energy consumption. At the same time, activate the electrostatic neutralization device (ion wind) on the inner wall of the sorting zone to prevent fine particles from adhering to the guide vane due to electrostatic adsorption, thus ensuring smooth stratification.

[0031] S3 automatically transports the coarse particles in the reflux zone to the return air-assisted large-piece crushing zone 6 for secondary crushing through the reflux mechanism, and performs fixed-mesh precise grading on the fine particles that float to the fine screening zone 3.

[0032] In this embodiment, the coarse particle reflux mechanism is activated. Based on the material stratification results after coarse classification by the S2 composite force field, the coarse qualified particles that have settled into the qualified particle buffer zone 5 are transported back to the gas-assisted large-piece crushing zone 6 for secondary crushing through the reflux mechanism, thus executing a closed-loop reflux crushing process.

[0033] The coarse particle return mechanism adopts a variable frequency screw conveyor. The speed of the variable frequency screw conveyor is set according to the preset coarse and fine particle output ratio. The adjustment range is 10-30 r / min, preferably 20 r / min. With the help of the set flow regulating valve, the return flow rate is adjusted in real time according to the coarse particle ratio monitored online, and the coarse particle return flow rate is controlled to be 10-50 kg / h to ensure that the return frequency matches the crushing efficiency.

[0034] Coarse particles fall into the feed end 13 of the reflux mechanism through the qualified particle buffer zone 5. They are conveyed by variable pitch spiral blades and accurately sent to the bottom of the one-way flow valve in the air-assisted large-piece crushing zone 6 through the sealed reflux pipe to avoid mixing with the newly fed material. At the same time, the reflux pipe is double sealed with mechanical seal and fluororubber gasket to prevent fine powder leakage.

[0035] After the coarse particles are returned to the crushing zone, the system automatically fine-tunes the crushing parameters (rotor speed maintained at 150-200 r / min, stator-rotor gap finely adjusted to 12-14 mm, air-assisted pressure maintained at 0.15-0.2 MPa), only further breaking down the coarse particles into fine particles of 3-5 mm, without causing over-crushing, ensuring that the product after secondary crushing is still within the qualified size range.

[0036] When the online monitoring module 11 detects that the ratio of coarse to fine particles reaches the preset value, and the amount of coarse particles in the qualified particle buffer area 5 is lower than the threshold (≤5kg), the reflux mechanism automatically reduces the speed to 5r / min to maintain low flow reflux; when the ratio deviation exceeds ±10%, the speed is increased back to the preset value to ensure the ratio is stable.

[0037] Simultaneously, fine particles that float to the fine screening zone 3 of the screen are precisely classified with a fixed mesh size. Through multiple layers of fixed mesh grading screens, precise separation of coarse and fine particles and control of the output ratio are achieved.

[0038] In this embodiment, the fine screening zone 3 of the screen adopts a double-layer fixed mesh graded screen, consisting of a first-stage screen 14 from top to bottom, used to intercept residual coarse particles with a size ≥5mm, and a second-stage screen 15, used to separate fine particles of 3-5mm. The screen is installed at an inclination angle of 10°-15°, preferably 12°, to facilitate particle passage and fall back.

[0039] Driven by the axial upward airflow (wind speed 0.8-1.5m / s), fine particles fall evenly onto the first-stage screen 14. Residual coarse particles with a size ≥5mm are intercepted and fall back to the qualified particle buffer zone 5 along the screen's inclination angle to participate in subsequent reflux crushing. Fine particles with a size of 3-5mm pass through the screen and fall onto the second-stage screen 15. After further screening, the 3-4mm fine particles that pass through the screen and the 4-5mm fine particles that do not pass through the screen enter the corresponding finished product sealed collection tank 12 through independent sealed collection channels, thereby achieving the separation of qualified products in multiple zones.

[0040] Simultaneously, in this embodiment, the screen anti-clogging mechanism is activated. Pulse jet nozzles on the back of each screen layer spray dry inert gas at a frequency of 5-10 times / min (preferably 8 times / min) at a jet pressure of 0.2-0.3 MPa. This, combined with a low-frequency micro-vibration mechanism (vibration frequency 5-10 Hz, amplitude 0.5-1 mm), cleans particles from the screen surface in real time, preventing clogging. For hydrophilic aerogels, the jetting frequency is increased to maintain a dry screen surface; for hydrophobic aerogels, an ion wind electrostatic eliminator is activated to neutralize static electricity in the particles, preventing them from adsorbing onto the screen.

[0041] Based on the material type, the parameters of reflux crushing and fine screening are adapted accordingly to ensure the accuracy of ratio control.

[0042] Since hydrophilic aerogels are prone to absorbing moisture and agglomerating, the reflux speed can be appropriately increased to 25-30 r / min to increase the frequency of secondary crushing and avoid coarse particle agglomeration that leads to proportion deviation. At the same time, the screen pulse jet frequency should be increased to 10 times / min to keep the screen dry, ensure screen penetration efficiency, and avoid a low proportion of fine particles due to agglomeration.

[0043] Hydrophobic aerogels have good fluidity but strong static electricity, so the reflux speed can be maintained at 15-20 r / min, reducing energy consumption. At the same time, the operating power of the static elimination device is enhanced, and the ion wind speed is increased to 1 m / s to prevent particles from adsorbing onto the screen or reflux pipe, ensuring smooth separation of coarse and fine particles and a stable ratio.

[0044] Furthermore, throughout the process, the online monitoring module 11 collects core data in real time to construct closed-loop control logic, ensuring stable and precise proportions between the reflux crushing and fine screening. In this embodiment, the core data includes: Reflux parameters: reflux mechanism speed, coarse particle reflux flow rate (collected by electromagnetic flowmeter, accuracy ±0.5%), and qualified particle buffer zone 5 accumulation amount (collected by liquid level sensor, accuracy ±0.1kg). Screen parameters: screen penetration rate (collected by a flow sensor, accuracy ±0.1kg / h), particle adhesion on the screen surface (indirectly collected by a pressure sensor), and output of coarse and fine particles in the finished product sealed collection tank 12. Closed-loop correction: When the deviation of the output ratio of coarse and fine particles exceeds ±10%, or the screen penetration rate decreases by more than 20%, or the accumulation in the buffer zone exceeds 10kg, the system automatically performs correction operations: When the ratio is deviated, the speed of the reflux mechanism is adjusted (adjustment range ±5r / min); when the screen penetration rate decreases, the pulse jet frequency and micro-vibration amplitude are increased; when the accumulation exceeds the standard, the reflux speed is increased to ensure continuous process and accurate ratio.

[0045] After being finely sieved and graded, the qualified aerogel blocks (such as 3-4mm and 4-5mm fine particles, and 5-8mm coarse particles) enter their respective independent sealed finished product collection tanks 12. Each collection tank 12 is equipped with a dustproof sealing cap on top and a discharge valve on the bottom for easy subsequent packaging. Any residual coarse particles that do not pass through the sieve fall back into the qualified particle buffer zone 5 for reflux crushing, ensuring that all materials are qualified products with no waste.

[0046] S4 collects real-time data on particle size distribution and fine powder concentration through online particle size monitoring, constructs closed-loop control logic, and adjusts crushing intensity, airflow speed and pressure, coarse particle return flow and screen parameters in reverse to adjust the ratio of coarse and fine particles, and continuously completes the crushing, sorting, grinding and fine screening cycle.

[0047] In this embodiment, the closed-loop control logic involves setting up multiple online monitoring points inside cavity 1 and the finished product channel to continuously collect particle status and operating parameters throughout the entire process, with a collection frequency of no less than 10Hz. This includes particle size distribution, output and proportion data, operating parameters, and data preprocessing. The data is then transmitted to the control cabinet in real time. The control cabinet has a built-in intelligent algorithm that adjusts parameters in real time based on the monitoring data. When the fine powder concentration exceeds the standard, the crushing speed is reduced, the crushing gap is decreased, the crushing intensity is weakened, and the airflow velocity is lowered. When the proportion of coarse particles exceeds the standard, the crushing speed is increased, the return flow rate is increased, and the coarse particle crushing efficiency is enhanced.

[0048] The particle size distribution was measured using an online laser particle size analyzer. Data was collected simultaneously at three locations: the middle of the dynamic floating sorting zone 4, the entrance of the fine sieve zone 3, and the finished product collection channel. The real-time size distribution, quantity concentration, and volume percentage of the coarse particle range (5–8 mm) and the fine particle range (3–5 mm) were obtained.

[0049] Production and ratio data are obtained by using mass flow sensors built into each finished product collection channel to measure the instantaneous and cumulative production of coarse and fine qualified particles in real time, and to calculate the current actual coarse and fine output ratio.

[0050] Operating parameters are collected by real-time monitoring of crusher motor speed, blower speed, air-assisted pressure, coarse particle return flow rate, screen pulse backflushing frequency, cavity humidity, and electrostatic voltage.

[0051] The acquired signals are filtered by moving average (window N=5) and outlier removal to eliminate measurement errors caused by airflow disturbances and instantaneous particle fluctuations, forming a stable dataset that can be used for control.

[0052] Specifically, in this embodiment, the actual ratio of coarse and fine particles produced online is compared with the system's preset target ratio in real time, the ratio deviation value is calculated, and the ratio is adjusted in reverse according to the preset control logic.

[0053] The proportional deviation value can be expressed as: ; In the formula, This represents the actual coarse particle yield; This represents the actual fine particle yield; The target ratio is preset.

[0054] Execute the grading judgment logic based on the magnitude of the deviation. when deviation If the ratio is deemed acceptable, the system will maintain its current operating parameters. when deviation If the deviation is found to be proportional, the closed-loop control program will be immediately initiated to correct the relevant operating parameters.

[0055] (1) When the proportion of coarse particles is too high and the proportion of fine particles is insufficient, the rotation speed of the coarse particle return spiral should be increased to increase the return flow rate. The specific control strategy can be as follows: Increase the speed of the crusher motor: In the formula, The coarse particle processing coefficient (e.g., 0.15-0.4) is used to enhance the efficiency of secondary crushing of coarse particles into fine particles. Increasing the coarse particle return flow rate is expressed as: In the formula, This is the reflow enhancement factor (e.g., 0.2-0.5).

[0056] Simultaneously, the axial upward airflow speed is slightly increased to enhance the ability of fine particles to rise.

[0057] (2) When the proportion of fine particles is too high and the proportion of coarse particles is insufficient, the rotation speed of the coarse particle return spiral should be reduced to decrease the return flow rate. The specific control strategy can be as follows: Reduce the speed of the crusher motor: In the formula, This is the fine powder inhibition coefficient (e.g., 0.1-0.3, adjustable). Appropriately reducing the sorting airflow velocity to decrease excessive enrichment of fine particles is expressed as: ; Maintain or reduce the reflux flow rate to avoid repeated grinding of coarse particles, which can exacerbate over-grinding. Reduce the generation of fine powder at the source. Regression within the allowed range.

[0058] If monitoring shows that hydrophilic aerogels cause coarse agglomeration, increase the flow rate of the drying air path and strengthen the backflushing of the screen; if monitoring shows that hydrophobic aerogels have high static electricity causing fine particles to adhere, increase the electrostatic elimination power of the ion wind to ensure smooth sorting.

[0059] Traditional grinding and grading equipment only uses single-parameter open-loop control, which cannot establish a multi-variable coupling relationship between particle size distribution and grinding / airflow / reflux, nor can it suppress crushing intensity in real time according to fine powder concentration. This embodiment achieves dynamic adaptive closed-loop preparation of aerogel micro powder for the first time through particle size ratio deviation-multi-parameter linkage adjustment algorithm, which solves the industry contradiction of "grinding coarse particles without producing excessively fine powder" from the mechanism, and improves the accuracy of ratio control.

[0060] Meanwhile, in this embodiment, the cavity 1 adopts a fully enclosed design, combined with a micro-negative pressure working condition, to completely solve the problem of aerogel dust, and realize intelligent closed-loop control of crushing, sorting and reflux at the same time.

[0061] Option 2 In this embodiment, an integrated preparation system for grinding, floating, and classifying aerogel micropowder is also provided, which is applied to the above-mentioned integrated preparation method for grinding, floating, and classifying aerogel micropowder, as shown in the attached figure. Figure 2 As shown, the cavity includes a sealed, vertical, integrated cylindrical chamber 1. The outer wall of the chamber 1 is equipped with an insulation layer and an observation mirror. In this embodiment, the chamber 1 is divided into the following sections from top to bottom: a finished product collection area 2, a fine screening area 3, a dynamic floating sorting area 4, a qualified particle buffer area 5, an air-assisted large particle crushing area 6, and a coarse particle return area 7. There are no rigid partitions between the areas. The chamber 1 adopts a sealed structure as a whole. All joints and flange connections are sealed with high-temperature resistant fluororubber gaskets and dustproof components to ensure that there is no dust leakage inside or outside the chamber.

[0062] In this embodiment, a feed end 13 is provided on the side of the cavity 1, which is directly connected between the qualified particle buffer zone 5 and the air-assisted large-piece crushing zone 6, allowing the material to fall directly into the crushing zone. A one-way anti-spray feeding mechanism is provided at the interface of the feed end 13, including a feed hopper, a one-way flow guide valve, and a sealed feed pipe. The top of the feed hopper is provided with a snap-on dustproof sealing cover, and a humidity sensor is installed on the inner wall of the feed hopper to monitor the humidity inside the cavity.

[0063] The one-way flow guide valve adopts a flexible sealing valve core structure and is installed between the feed hopper and the air-assisted large-piece crushing zone 6. It only allows materials to pass downward in one direction, blocking the airflow and fine powder from splashing in the opposite direction. The valve core opening pressure is 0.03MPa to avoid material accumulation and blockage.

[0064] The sealed feed pipe is made of wear-resistant sealing material. The pipe is connected to a low dew point dry inert gas storage tank to maintain a slight positive pressure inside the pipe and form a one-way airflow barrier. An electromagnetic flow meter (measurement range 0-100kg / h, accuracy ±0.5%) is installed in the middle of the pipe to monitor the feed flow rate in real time.

[0065] The finished product collection area 2 at the top of the cavity 1 is a conical section flow guide structure, and a fine powder discharge pipe 8 is provided at the top, which is connected to the pulse backflushing fine powder recovery tank. It is only used for airflow stabilization and ultrafine powder recovery to avoid ultrafine powder adhesion and accumulation.

[0066] In this embodiment, at least two independent sealed finished product collection tanks 12, discharge channels and discharge valves are respectively provided outside the cavity of the finished product collection area 2, which can be disassembled, discharged and cleaned independently without interfering with each other.

[0067] The finished product sealed collection tank 12 adopts a stainless steel sealed structure with a volume of 50-100L. Each sealed collection tank 12 corresponds to a qualified product within a size range (such as 3-4mm, 4-5mm, 5-8mm). The bottom of the sealed collection tank 12 is connected to the screen outlet through a sealed discharge channel, and the top is equipped with a dustproof sealing cover to prevent dust leakage.

[0068] The discharge channel adopts a sealed design and is sealed to the screen outlet and the bottom of the sealed collection tank 12. The top of the sealed collection tank 12 is equipped with a manual / electric discharge valve for easy packaging of finished products. The discharge valve adopts a sealed structure to ensure no dust leakage when closed.

[0069] The fine screening zone 3 is equipped with multi-layered fixed-mesh grading screens, each with a corresponding independent finished product collection channel. A pulse jet nozzle and a low-frequency micro-vibration mechanism are located on the back of the screen, connected to the drying air path to maintain a slight positive pressure. An ion wind electrostatic eliminator is installed above the screen to neutralize the static electricity of the hydrophobic aerogel, preventing adsorption and clogging.

[0070] In this embodiment, the fine screening zone 3 is equipped with a fine screening assembly and a screen anti-clogging mechanism.

[0071] The fine screening component includes a double-layer fixed mesh grading screen, a screen support, a flow sensor, and a screen angle adjustment mechanism.

[0072] Specifically, the double-layer grading screen is made of anti-static 304 stainless steel. The first-stage screen has a mesh size of 14 (10 meshes) and a corresponding aperture size of 2mm. The second-stage screen has a mesh size of 15 (6 meshes) and a corresponding aperture size of 3mm. The screen thickness is 1-2mm, and the surface is treated with Teflon for non-stick properties, reducing particle adhesion. The screen is fixed by a detachable screen support for easy maintenance and replacement. Each screen layer is connected to an independent finished product sealed collection tank 12 outside the cavity through a side-sealed channel, enabling separate collection and rapid disassembly of products with different particle sizes.

[0073] The screen support is made of stainless steel and is fixedly connected to the side wall of the cavity 1. The support is equipped with an angle adjustment knob, and the screen installation tilt angle can be adjusted within a range of 10°-15°. It can be flexibly adjusted according to the material flow to ensure smooth particle passage.

[0074] The flow sensor is a mass flow sensor, installed at the mesh passage of each layer of screen, with a measurement range of 0-100 kg / h and an accuracy of ±0.1 kg / h. It monitors the mesh passage rate in real time and feeds it back to the online monitoring module 11 to determine whether the screen is clogged.

[0075] The screen anti-clogging mechanism includes a pulse jet assembly, a low-frequency micro-vibration mechanism, and an ion wind electrostatic elimination device, which are linked with the screen fine screening assembly.

[0076] The pulse jet assembly includes a pulse controller, pulse jet nozzles, and a high-pressure air path. The pulse jet nozzles are evenly arranged on the back of each layer of screen, with a quantity of 6-8 nozzles. The nozzles face the screen surface. The jet pressure is adjustable from 0.2 to 0.3 MPa, and the pulse frequency is adjustable from 5 to 10 times / min. The pulse controller is linked with the online monitoring module 11 and can automatically adjust the jet frequency according to the material type and screen condition.

[0077] The low-frequency micro-vibration mechanism is connected to the screen support and uses an electromagnetic vibrator with a vibration frequency of 5-10Hz, an amplitude of 0.5-1mm, and adjustable vibration intensity. It cleans the particles adsorbed on the screen surface through low-frequency vibration, avoiding screen blockage, while avoiding excessive vibration that could damage the aerogel block skeleton.

[0078] The ion wind electrostatic elimination device is linked with the electrostatic elimination device in the dynamic floating sorting zone 4. The ion wind generator is located at the top of the screen fine screening zone 3, with the air outlet facing the screen. The ion wind speed is 0.5-1m / s and the output voltage is 5-10kV. It is used to neutralize the static electricity on the surface of hydrophobic aerogel particles and prevent them from adsorbing onto the screen.

[0079] The dynamic floating sorting area 4 in the middle of cavity 1 is set as a cylindrical section, which is the core sorting space and accounts for 40% of the total height of the cavity.

[0080] In this embodiment, the dynamic floating sorting mechanism is located within the dynamic floating sorting zone 4, and includes a variable frequency fan, radial circulation guide vanes 9, a sealed air duct, and an airflow regulating component. The variable frequency fan, a high-pressure centrifugal variable frequency fan, is located on the outer side of the bottom of the cavity. Its outlet connects the air-assisted large-piece crushing zone 6 and the dynamic floating sorting zone 4 via a sealed airflow pipe, providing axial upward airflow. The airflow adjustment range is 500-2000 m³ / h. 3 / h, the wind pressure adjustment range is 500-2000Pa, the air outlet of the fan is connected to the air-assisted large piece crushing zone 6 and the dynamic floating sorting zone 4 through a high temperature resistant sealed air duct, which is used to provide a stable axial upward airflow. The fan is electrically connected to the online monitoring module 11 to receive PID closed-loop regulation signals and realize adaptive wind speed adjustment.

[0081] A single layer of radial circulation guide vanes 9 are fixedly arranged in the dynamic floating sorting zone 4. That is, multiple radial circulation guide vanes 9 are evenly arranged around the inner wall, with a quantity of 8-12, preferably 10. The blades are tilted at a certain angle (15°-30°) around the circumference. The blades are made of arc-shaped antistatic 304 stainless steel with a radius of curvature of 50-80mm, preferably 65mm, and the tilting direction is consistent. The multiple guide vanes are evenly distributed around the circumference and are linked with the static elimination mechanism to further reduce the risk of static adsorption. Together, they promote the airflow in the entire sorting zone to form a continuous and stable rotating circulation, which forms a composite force field with the axial upward airflow to achieve the initial separation of coarse and fine qualified particles.

[0082] The sealed air duct adopts a double-layer stainless steel sealing structure. The inner layer is an airflow channel, and the outer layer is a heat insulation layer to avoid the airflow temperature change affecting the density of the aerogel block. Fluororubber sealing gaskets are used at all air duct connections to ensure no airflow leakage and maintain a slight positive pressure in the cavity.

[0083] As the airflow passes upward through the fixed, tilted guide vanes, it is forced tangentially, thus forming a stable rotating circulation in the sorting zone. This eliminates the need for additional motors or transmission components, resulting in a simpler and more reliable structure, and also avoids contact wear between rotating parts and aerogel powder. This circulation not only breaks up aerogel particle agglomerates, preventing fine powder from encapsulating coarse particles and causing sorting distortion, but also enhances the force-based separation caused by particle size differences, improving sorting accuracy.

[0084] An installation port for an online monitoring module 11 is also provided on the side wall of the dynamic floating sorting zone 4. The online monitoring module 11 is located in the dynamic floating sorting zone 4 and includes a wind speed sensor, a pressure sensor, a laser particle size analyzer, and a data processing unit.

[0085] The wind speed sensor can be a Pitot tube type, installed at the air outlet of the sealed air duct, with a measurement range of 0-5 m / s and an accuracy of ±0.05 m / s, monitoring the axial airflow speed in real time. The pressure sensor can be a diffused silicon pressure sensor, installed at the top and bottom of the dynamic floating sorting zone 4, with a measurement range of 0-5000 Pa and an accuracy of ±0.001 MPa, monitoring the airflow pressure distribution to ensure a stable circulating flow field. The laser particle size analyzer can be a backscattered laser particle size analyzer, with the probe located in the middle of the dynamic floating sorting zone 4, with a measurement range of 1-10 mm and an accuracy of ±0.1 mm, acquiring particle size distribution and concentration data in real time. The data processing unit has a built-in embedded microprocessor, connected to all sensors via RS485 communication protocol, using a moving average filtering method to reduce noise in the acquired data, and simultaneously linked with the PID closed-loop control unit to output adjustment signals.

[0086] It also includes an electrostatic elimination mechanism, comprising an ion wind generator and an electrostatic collection electrode. The ion wind generator is located at the top of the dynamic floating sorting zone 4, with its outlet facing the guide vane. The ion wind speed is 0.5-1m / s, and the output voltage is 5-10kV. It is used to neutralize the static electricity on the surface of hydrophobic aerogel particles and prevent particles from adhering to the guide vane. The electrostatic collection electrode is located on the surface of the guide vane and connected to the grounding terminal to promptly discharge residual static electricity.

[0087] The qualified particle buffer zone 5 is located below the dynamic floating sorting zone 4 and above the air-assisted large piece crushing zone 6. It is an annular conical transition cavity with smooth inner walls and anti-static treatment. It is used to receive and temporarily store coarse particles that have settled down after being sorted by the composite force field, so as to avoid the particles directly impacting the crushing zone and causing turbulence. At the same time, it provides a stable and continuous material source for the coarse particle return mechanism, ensuring uniform return flow.

[0088] The lower part of the qualified particle buffer zone 5 is connected to the feed end 13 of the coarse particle return mechanism, and the upper part smoothly transitions to the dynamic floating sorting zone 4, allowing coarse particles to slide naturally along the inner wall and be temporarily stored in an orderly manner. This forms a physical separation space between coarse and fine particles, preventing coarse particles from mixing with rising fine particles and improving the classification accuracy.

[0089] Below the qualified particle buffer zone 5 is a gas-assisted large-piece crushing zone 6. The gas-assisted large-piece crushing mechanism is located in the gas-assisted large-piece crushing zone 6, including a crushing stator and rotor assembly, a variable frequency crushing motor, an annular air distribution pipe, and an electric pressure regulating valve.

[0090] In this embodiment, the crushing stator and rotor assembly is made of wear-resistant ceramic material. The stator is an annular ceramic bushing fixed to the inner wall of the crushing chamber. The rotor is a large-spacing arc-shaped crushing blade, coaxially connected to a variable frequency crushing motor. The motor is fixed to the outside of the chamber, and the motor shaft passes into the crushing chamber through a mechanical seal to prevent air and powder leakage. The adjustable range of the stator and rotor gap is 10-20mm. In this embodiment, 15mm is preferred.

[0091] The variable frequency crushing motor has a resolution of 1000 lines / revolution, a response time of ≤10ms, and a speed adjustment range of 100-500 r / min, preferably 150-200 r / min, to achieve low-speed shearing crushing. An annular air distribution pipe is installed around the bottom of the crushing zone, with 4-6 air nozzles evenly distributed, facing the center of the crushing chamber. The nozzles are connected to an external inert gas storage tank via a sealed air pipe. An electric pressure regulating valve is installed on the air pipe to adjust the air pressure, with an adjustment range of 0.1-0.3 MPa, preferably 0.15-0.2 MPa.

[0092] The online monitoring module 11 also includes a speed sensor, a displacement sensor, a pressure sensor, and a temperature sensor located in the gas-assisted large-block crushing zone 6.

[0093] The speed sensor is installed at the motor shaft end to collect the motor speed in real time. The displacement sensor is installed on the side wall of the crushing chamber to monitor the stator-rotor clearance in real time. The pressure sensor is installed at the inlet of the annular air distribution pipe to collect the air-assisted airflow pressure in real time. The temperature sensor, using a thermocouple, is installed on the inner wall of the crushing chamber to monitor the crushing chamber temperature.

[0094] The sensor is connected to the system control cabinet via RS485 communication protocol. The data is transmitted to the data acquisition module in real time. The moving average filtering method (window size of 5 data points) is used for noise reduction and filtering to ensure data accuracy.

[0095] At the bottom of the cavity 1, there is a coarse particle reflux zone 7 with a cone-shaped section and a cone angle of 45°-60°. The coarse particle reflux mechanism is located at the bottom of the cavity, with its input end connected to the coarse particle reflux zone 7 and its output end connected to the air-assisted large piece crushing zone 6.

[0096] In this embodiment, the coarse particle reflux mechanism employs a variable frequency spiral conveyor, a sealed reflux pipe, a liquid level sensor, and a reflux control unit.

[0097] The variable frequency screw conveyor mechanism features a sealed stainless steel housing with internal variable pitch screw blades (pitch adjustment range 50-100mm) and a variable frequency speed-regulating motor (speed adjustment range 0-50r / min, accuracy ±1r / min). The motor is electrically connected to the online monitoring module 11, receiving proportional control signals to achieve adaptive speed adjustment. The feed end 13 of the conveyor mechanism connects to the qualified particle buffer area 5, and the discharge end connects to the unidirectional flow valve below the air-assisted large-piece crushing area 6 via a sealed return pipe.

[0098] The sealed return pipeline uses wear-resistant sealing material, with a pipeline diameter of 80-120mm, preferably 100mm. The pipeline connection uses a double seal of mechanical seal and fluororubber gasket to prevent fine powder leakage. The inner wall of the pipeline is polished and antistatic treated to prevent the adsorption of hydrophobic aerogel particles.

[0099] The liquid level sensor is a capacitive type, installed on the inner wall of the qualified particle buffer zone 5. It has a measurement range of 0-50 kg and an accuracy of ±0.1 kg, monitoring the accumulation of coarse particles in real time and providing data support for adjusting the speed of the reflux mechanism. The reflux control unit has a built-in PLC controller (model S7-1200), which is linked with the variable frequency motor and liquid level sensor. It receives proportional data from the online monitoring module 11 and outputs speed adjustment signals to achieve precise control of the reflux frequency and flow rate.

[0100] The system includes a one-way anti-spray feeding mechanism, an air-assisted large-piece crushing mechanism, a dynamic floating sorting mechanism, a coarse particle return mechanism, and an online monitoring module 11. These mechanisms work together to achieve large-piece crushing, grading, and proportion control of aerogel, thereby obtaining a preset proportion of aerogel micro powder.

[0101] It also includes a closed-loop control cabinet 10, equipped with an online particle size monitoring module, a data processing unit, a closed-loop control unit, and an actuator linkage interface. The online monitoring module 11, the air-assisted large-particle crushing mechanism, the variable frequency fan, and the coarse particle return mechanism are all electrically connected to the closed-loop control cabinet 10. In this embodiment, the online monitoring module 11 uses a laser online particle size monitoring probe, with the probe end sealed and inserted into the lower part of the dynamic floating sorting zone 4 (avoiding the circulation blind zone), to collect particle size distribution and fine powder concentration data in real time, and transmits the electrical signal to the closed-loop control cabinet 10 through a signal line.

[0102] The closed-loop control cabinet 10 has a built-in touch screen and adaptive control algorithm, and integrates a frequency conversion drive module and a signal receiving module. It is connected to the online monitoring module 11, crushing motor, frequency conversion fan, reflux screw motor and pneumatic discharge valve through control cables to realize full-process automated control.

[0103] Using existing conventional processes as a control group, and comparing them with the experimental group of this scheme, the effectiveness of this scheme in terms of proportional controllability, production frequency, material utilization rate, and production continuity is quantified through the comparison of multiple sets of data.

[0104] Experiment 1: Comparison of rotor speed and stator-rotor clearance in the air-assisted large-piece crushing zone Table 1 Comparison of rotor speed and stator-rotor clearance.

[0105] In this experiment, the control group used a conventional pulverizer for crushing, adjusting the rotor speed and the gap between the stator and rotor. Table 1 shows that conventional high speed with a small gap leads to excessive shearing of the aerogel, producing a large amount of ultrafine powder, directly undermining the basis for subsequent proportioning control. Too low a speed and too large a gap fail to effectively break down large pieces. A speed of 150-200 r / min with a 15 mm gap is the only optimal parameter that achieves "breaking down only large pieces without excessive crushing," providing a suitable material basis for subsequent coarse particle recirculation control.

[0106] Experiment 2: Comparison of Axial Upward Airflow Speed ​​in Dynamic Floating Sorting Zone Table 2 Comparison of wind speeds in axial updrafts

[0107] As shown in Table 2, excessively low wind speeds cannot lift fine particles, while excessively high speeds will engulf coarse particles, both leading to grading failure. The range of 0.8-1.5 m / s (1.2 m / s is the global optimum, and 1.5 m / s is the critical upper limit for material compatibility; exceeding this limit will result in failure) is the optimal range for achieving efficient grading of coarse and fine particles. This range ensures that fine particles are effectively lifted into the screen for grading without causing coarse particles to float, and is the core guarantee for subsequent ratio control.

[0108] Experiment 3: Comparison of airflow velocity and guide vane angle adaptation of hydrophilic / hydrophobic aerogels 1) Comparison of hydrophilic aerogels Table 3 Comparison results of hydrophilic aerogels

[0109] 2) Comparison of hydrophobic aerogels Table 4 Comparison results of hydrophobic aerogels

[0110] A comparison of Tables 3 and 4 shows that the same set of parameters cannot be adapted to both hydrophilic and hydrophobic aerogels. Conventional parameters can lead to hydrophilic aerogels clogging the mesh and hydrophobic aerogels adhering to the mesh. The differentiated parameters designed for different materials in this solution are key to solving these two problems, ensuring both the grading efficiency and production continuity for both materials.

[0111] Experiment 4: Comparison of rotational speed and return flow rate of the coarse particle reflux mechanism Table 5 Comparison of Rotation Speed ​​and Recirculation Flow Rate

[0112] As can be seen from the comparison in Table 5, both excessively low and excessively high reflux speeds will lead to proportional deviations. However, the reflux flow rate in this solution, set within the range of 10-30 r / min (preferably 20 r / min), can precisely match the crushing efficiency, achieving accurate control of the target proportion with a deviation far lower than that of conventional processes.

[0113] In this embodiment, addressing the industry pain points of imbalanced block size ratio and high production frequency during the large-scale aerogel crushing process, a closed vertical integrated cavity is constructed. From top to bottom, it is arranged with a finished product collection area 2, a fine screening area 3, a dynamic floating sorting area 4, a qualified particle buffer area 5, an air-assisted large-scale crushing area 6, and a coarse particle return area 7. It integrates core mechanisms such as unidirectional anti-spray feeding, air-assisted large-scale crushing, composite force field floating sorting, coarse particle return, online monitoring, and closed-loop control. With a closed-loop process of "crushing-grading-returning-control", irregular large-sized aerogel blocks are crushed into blocks of different sizes. The composite force field achieves initial stratification of coarse and fine particles, followed by fine screening and grading. At the same time, the coarse particles are returned for secondary crushing. Combined with online particle size monitoring and PID closed-loop control, the output ratio of coarse and fine particles is precisely controlled, and the ratio deviation is stabilized within ±10%.

[0114] This innovative design utilizes online particle size data to reversely control grinding parameters, breaking the bottleneck of the disconnect between grinding and grading. It enables the production of qualified aerogel micropowder in a preset ratio through a single crushing operation, significantly reducing production frequency and improving production efficiency. The material utilization rate reaches over 99%. Simultaneously, the fully enclosed design prevents dust leakage and is suitable for the continuous and stable production of hydrophilic and hydrophobic aerogels. It effectively solves the core contradiction in existing technologies where it is difficult to balance the controllability of the ratio with production efficiency. It combines high controllability, high utilization rate, and environmental friendliness, significantly improving the economy and applicability of aerogel micropowder preparation.

[0115] The above descriptions are merely embodiments of the present invention, and common knowledge such as specific technical solutions and / or characteristics are not described in detail here. It should be noted that those skilled in the art can make various modifications and improvements without departing from the technical solutions of the present invention, and these should also be considered within the scope of protection of the present invention. These modifications and improvements will not affect the effectiveness of the implementation of the present invention or the practicality of the patent. The scope of protection claimed in this application should be determined by the content of its claims, and the specific embodiments described in the specification can be used to interpret the content of the claims.

Claims

1. A method for the integrated preparation of aerogel micropowder through grinding, floating, and classification, characterized in that, Includes the following steps: S1, the large aerogel material to be processed is placed into the air-assisted large-piece crushing zone of the sealed vertical integrated cavity through a one-way sealed feeding structure. The initial crushing process is carried out by a composite crushing method of low-speed shearing and air-assisted crushing, which breaks the large aerogel into aerogel blocks of different sizes. The air-assisted crushing is to introduce a small amount of dry inert protective gas into the grinding chamber to form an air cushion layer that reduces hard contact wear between particles. S2, a composite force field of axial upward airflow and radial rotational circulation is constructed in the cavity to form the first screening. The airflow parameters of the composite force field are: the wind speed of the axial upward airflow is controlled at 0.8-1.5m / s, and the wind pressure is maintained at 500-2000Pa. By utilizing the gravity-buoyancy difference formed by the size and mass difference of aerogel particles, dynamic floating stratification is achieved, so that fine particles float to the fine screening area of ​​the screen with the airflow, and coarse particles settle to the coarse particle return area at the bottom of the cavity. S3 automatically transports coarse particles in the reflux zone back to the air-assisted large-piece crushing zone for secondary crushing through the reflux mechanism, and performs fixed-mesh precise grading on fine particles that float to the fine screening zone. S4 collects real-time data on particle size distribution and fine powder concentration through online particle size monitoring, constructs closed-loop control logic, and adjusts the crushing intensity, airflow speed and pressure, coarse particle return flow rate and screen parameters in reverse to adjust the ratio of coarse and fine particles, so that the coarse and fine particles in the cavity meet the ratio requirements, and continuously completes the crushing, sorting, grinding and fine screening cycle.

2. The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to claim 1, characterized in that: In S1, the grinding rotor speed is controlled at 150-200 r / min with frequency conversion adjustment.

3. The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to claim 1, characterized in that, In S2, based on the difference characteristics between aerogel particle size and buoyancy, gravity, and centrifugal force, a composite force field of axial airflow stratification and radial circulation dispersion is constructed in the floating sorting zone. The force field is adjusted in real time according to the target qualified particle size, and the airflow parameters are adapted to different target qualified particle sizes by frequency conversion control.

4. The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to claim 1, characterized in that: In S2, the parameters of the composite force field are also finely adjusted according to the material type and real-time operating data. For hydrophilic aerogels, the axial airflow velocity is increased to 1.3-1.5 m / s and the tilt angle of the guide vanes is increased. For hydrophobic aerogels, the axial airflow velocity is maintained at 0.8-1.1 m / s and the tilt angle of the guide vanes is 15°±5°.

5. The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to claim 1, characterized in that: In S3, a variable frequency screw conveyor is used to return coarse particles that have settled into the qualified particle buffer area to the crushing zone for secondary grinding. The screw speed is adjustable from 10 to 30 r / min, and the return flow rate is controlled from 10 to 50 kg / h. The ratio of coarse to fine particles is controlled by adjusting the return speed to ensure that the ratio deviation is ≤ ±10%.

6. The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to claim 2, characterized in that: In S4, the closed-loop control logic sets up multiple sets of online monitoring points inside the cavity and in the finished product channel to continuously collect particle status and operating parameters throughout the process. The monitoring data includes particle size distribution, output and ratio data, operating parameters and data preprocessing.

7. An integrated preparation system for grinding, floating, and classifying aerogel micropowder, characterized in that, The integrated preparation method for grinding, floating, and classifying aerogel micropowder according to any one of claims 1-6 includes a sealed vertical integrated cavity, which is divided from top to bottom into a finished product collection zone, a fine sieving zone, a dynamic floating sorting zone, a qualified particle buffer zone, an air-assisted large particle crushing zone, and a coarse particle recirculation zone; there are no rigid partitions between the zones; the finished product collection zone is equipped with at least two independent sealed collection tanks for collecting aerogel micropowder of different particle sizes; and a one-way anti-spray feeding mechanism is provided in the cavity. The system comprises a dynamic floating sorting mechanism, a coarse particle return mechanism, an air-assisted large particle crushing mechanism, and an online monitoring module. The dynamic floating sorting mechanism includes a variable frequency fan and radial circulation guide vanes. The variable frequency fan is located outside the cavity, and the radial circulation guide vanes are arranged in the dynamic floating sorting area. The coarse particle return mechanism is located at the bottom of the cavity, with its input end connected to the coarse particle return area and its output end connected to the air-assisted large particle crushing area. The air-assisted large particle crushing mechanism is located in the air-assisted large particle crushing area. The online monitoring module is located within the dynamic floating sorting area.

8. The integrated preparation system for grinding, floating, and classifying aerogel micropowder according to claim 7, characterized in that: A one-way anti-spray feeding mechanism is provided at the feeding end at the top of the cavity, including a feeding hopper, a one-way flow guide valve and a sealed feeding pipe; the top of the feeding hopper is provided with a snap-on dustproof sealing cover, and a humidity sensor is installed on the inner side wall of the feeding hopper to monitor the humidity inside the cavity.

9. The integrated preparation system for grinding, floating, and classifying aerogel micropowder according to claim 7, characterized in that: The fine screening area of ​​the screen is equipped with a fine screening component and a screen anti-clogging mechanism; the fine screening component includes a double-layer fixed mesh graded screen, a screen support, a flow sensor and a screen angle adjustment mechanism; the screen anti-clogging mechanism includes a pulse jet component, a low-frequency micro-vibration mechanism and an ion wind electrostatic elimination device, which are linked with the fine screening component.

10. The integrated preparation system for grinding, floating, and classifying aerogel micropowder according to claim 7, characterized in that: The radial circulation guide vanes are fixedly arranged in a single layer in the dynamic floating sorting area, with a quantity of 8-12 vanes. The vanes are tilted at a certain angle along the circumference, and the tilting direction is consistent.

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