A design and manufacturing method of negative pressure dust removal for a multi-specification double-sided milling equipment

Abstract

The application discloses a kind of multi-specification double-sided milling equipment negative pressure dust removal design manufacturing method, comprising the following steps: (1) milling machine milling operation;(2) broken machine crushing treatment;(3) air pipe transport;(4) cyclone separator separation operation;(5) fan suction and transport;(6) discharge filtration treatment.The application makes targeted improvement and innovation to dust suction structure, air flow organization and membrane for adsorbing aluminum dust, improves dust removal efficiency and aluminum scrap collection efficiency, improves production environment, reduces safety hazards caused by aluminum scrap accumulation, and significantly improves the comprehensive economic benefits of enterprises.

Description

Technical Field

[0001] This invention belongs to the field of aluminum processing technology, and in particular relates to a negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment. Background Technology

[0002] In the aluminum processing and manufacturing industry, traditional double-sided milling equipment for aluminum ingots mostly uses positive pressure cyclone dust collectors to collect aluminum chips and fine dust. With the advancement of intelligent manufacturing and the deep application of technology, the aluminum processing industry's requirements for clean production have upgraded from simple end-of-pipe treatment to full-process control. According to a 2023 survey by the China Nonferrous Metals Processing Industry Association, as many as 92% of aluminum processing enterprises listed dust control as a core indicator for green manufacturing upgrades.

[0003] In the aluminum processing and manufacturing industry, double-sided milling of aluminum ingots is a core forming process. Its high-speed cutting process generates a large amount of aluminum chips and dust particles of varying sizes. Among these, inhalable particulate matter (PM10) with a particle size less than 10μm and fine particulate matter (PM2.5) with a particle size less than 2.5μm not only pollutes the production environment but also seriously threatens the health of operators. Long-term inhalation can easily lead to occupational diseases such as pneumoconiosis. Traditional double-sided milling equipment for aluminum ingots widely adopts positive pressure cyclone dust collection technology. This technology is based on the principle of centrifugal separation, using the centrifugal force generated by the high-speed rotation of the airflow to separate larger particles such as aluminum chips from the airflow. Under ideal working conditions, positive pressure cyclone dust collectors can achieve a collection efficiency of 85%-90% for particles larger than 5μm. However, its purification capacity is significantly reduced when facing submicron-sized fine dust.

[0004] With the continuous improvement and strict enforcement of the "Integrated Emission Standard for Air Pollutants" (GB 16297-1996) and local environmental protection regulations, particulate matter emission limits for the aluminum processing industry are becoming increasingly stringent. Currently, most regions require emission concentrations to be controlled at 10 mg / m³. 3 In key environmental control areas, the standard has even been raised to 5 mg / m³. 3 However, in actual operation, positive pressure cyclone dust collection systems suffer from inherent drawbacks such as dust overflow caused by internal positive pressure and secondary dust generation due to ash accumulation in pipes. Their emission concentrations often exceed standards by 3-5 times, failing to meet current environmental protection requirements. Furthermore, these systems lack effective methods for handling fine dust, gradually becoming a technological bottleneck for the industry as cleanliness requirements in precision machining continue to rise. Therefore, designing and manufacturing efficient negative pressure dust collection systems is an inevitable choice for enterprises with multi-specification double-sided milling equipment to adapt to industry trends and achieve sustainable development.

[0005] In the aluminum processing industry, multi-specification double-sided milling equipment is mainly used for processing large slab ingots of different sizes. Currently, our company's double-sided milling equipment is mainly used for processing large slab ingots with specifications of 6200mm×495mm×1060mm. However, our original double-sided milling equipment uses a positive pressure cyclone dust removal method, which generates a large amount of dust both indoors and outdoors. After milling, the aluminum ingot produces fine aluminum strips, which are then sucked into a crusher for pulverization. The resulting dust and debris are then blown into a cyclone dust collector by a fan under positive pressure for separation, with clean air discharged outdoors. The problems include: a small amount of small aluminum shavings fly out of the cyclone separator's discharge port into the room after being blown under positive pressure, requiring frequent cleaning; fine aluminum shavings are also forced out of the discharge port into the room, resulting in a high concentration of aluminum dust particles indoors. Additionally, oil mist from the milling process permeates the room, posing a significant safety hazard. Summary of the Invention

[0006] This invention provides a negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment. In order to improve the dust removal method and aluminum chip collection effect of double-sided milling equipment, improve the production environment, and reduce the safety hazards caused by aluminum chip accumulation.

[0007] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0008] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine includes the following steps:

[0009] (1) Milling operation of milling machine

[0010] The aluminum plate ingot is milled on a large surface using the equipment's cutter head to produce fine aluminum strips;

[0011] (2) Crushing process by crusher

[0012] The fine aluminum strips produced by milling are crushed to generate short chips and aluminum dust.

[0013] (3) Duct delivery

[0014] The aluminum shavings and dust generated by the crusher are drawn into the cyclone separator to achieve material transfer;

[0015] (4) Cyclone separator separation operation

[0016] Large aluminum shavings are separated by cyclone separation, achieving preliminary solid-gas separation.

[0017] (5) Fan suction and conveying

[0018] It provides negative pressure power to suck up and transport materials and gases;

[0019] (6) Emission filtration treatment

[0020] The gas transported by the fan is filtered using a membrane that adsorbs aluminum dust to achieve compliant emissions.

[0021] Preferably, the aluminum ingot dimensions in step (1) are 6200mm × 495mm × 1060mm.

[0022] Preferably, the cutting parameters in step (1) are: linear speed 500-3000 mm / min, feed rate 10 mm.

[0023] Preferably, the diameter of the aluminum dust in step (2) is 1-100 μm.

[0024] Preferably, the cyclone separator in step (3) is provided with an airlock ash discharge device below it.

[0025] Preferably, the conveying path in step (3) is: from the crusher outlet to the cyclone separator inlet via a duct.

[0026] Preferably, the fan in step (5) has a power rating of 110KW and an air volume of 30000m³. 3 / h, wind pressure is 7200-7500pa.

[0027] Preferably, the method for preparing the membrane for adsorbing aluminum dust in step (6) includes the following steps:

[0028] (1) Raw material pretreatment

[0029] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60-80℃ for 4-6 hours to remove moisture;

[0030] 2) Activate the aluminum-based adsorbent at 100-120℃ for 2-3 hours to enhance its adsorption activity;

[0031] (2) Mixed dispersion

[0032] 1) Dissolve 25-35 parts of polylactic acid in 30-50 mL of ethyl acetate, and then emulsify it with 50-80 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at a high speed of 2000-3000 r / min for 10-15 min to form a W / O type emulsion.

[0033] 2) Add 20-35 parts of aluminum-based adsorbent, 5-10 parts of nano-silica, 3-8 parts of graphene oxide, and 1-3 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 500-1000 r / min for 30-60 min to obtain mixture a.

[0034] (3) Crosslinking reaction

[0035] Add 1-3 parts chitosan, 0.5-2 parts glutaraldehyde and 0.1-1 parts citric acid to mixture a, adjust the pH to 4-6, and then react at 40-60℃ for 2-4 hours to obtain mixture b;

[0036] (4) Film-forming treatment

[0037] Pour the mixture b into a flat mold, control the thickness to 50-100 micrometers, and dry it at 50-70℃ for 12-24 hours to form a wet film;

[0038] (5) Surface modification

[0039] The wet film is immersed in an ethanol solution containing nano zinc oxide and ultrasonically treated for 10-15 minutes at an ultrasonic power of 300-500W and a frequency of 20-40kHz to form an antibacterial coating. Then it is taken out and dried at room temperature for 2-4 hours to obtain the dried film.

[0040] (6) Heating treatment

[0041] The dried membrane is heated to 100-120℃ at a rate of 2-5℃ / min and held at that temperature for 1.5-2 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0042] Preferably, the mass ratio of polyvinyl alcohol to sodium dodecylbenzenesulfonate is (2-5):(0.5-2).

[0043] Preferably, the mass concentration of the nano-zinc oxide in the ethanol solution is 0.1-1%.

[0044] Compared with the prior art, the present invention has the following technical advantages:

[0045] (1) This invention aims to systematically optimize the dust removal process and aluminum chip collection mechanism of double-sided milling equipment through innovative design. Considering the characteristics of multi-specification double-sided milling equipment, the negative pressure dust removal technology of this invention comprehensively considers cutting parameters (linear speed 500-3000 mm / min, feed rate: 10 mm) and workpiece dimensions: 6200 mm × 495 mm × 1060 mm. Through precise optimization of the dust suction port position and pipeline routing, the dust suction port position is as close as possible to the dust suction fan, all pipelines adopt a ≥90-degree routing, and all bends use smooth transitions to minimize system resistance loss.

[0046] (2) The present invention makes targeted improvements and innovations to the dust collection structure, airflow organization and membrane for adsorbing aluminum dust, thereby improving dust removal efficiency and aluminum chip collection efficiency. The main improvement is the addition of an airlock ash discharge device below the original cyclone separator, which prevents gas loss while collecting aluminum chips, ensuring that the dust and aluminum chips generated in the processing area can be captured and recycled in a timely and efficient manner.

[0047] (3) The technical design of this invention not only helps enterprises successfully pass environmental compliance audits, but also effectively reduces the erosion of precision machining equipment by dust, significantly improving the overall economic benefits of enterprises. Therefore, building a high-efficiency negative pressure dust removal system has become a strategic choice for aluminum processing enterprises to break through environmental bottlenecks, enhance core competitiveness, and achieve green and sustainable development. Attached Figure Description

[0048] Figure 1 This is a schematic diagram of the original milling surface dust removal system;

[0049] Figure 2 This is a schematic diagram of the improved milling dust removal system;

[0050] Figure 3 This is a schematic diagram of a cyclone separator section;

[0051] Figure 4 This is the first scene of the negative pressure dust removal design and manufacturing of multi-specification double-sided milling equipment being put into use;

[0052] Figure 5 This is the second scene image showing the negative pressure dust removal design and manufacturing process of multi-specification double-sided milling equipment, which has been put into use.

[0053] Figure 6 This is the third scene image after the negative pressure dust removal design and manufacturing of multi-specification double-sided milling equipment was put into use. Detailed Implementation

[0054] The present invention will be further described in detail below with reference to specific embodiments. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0055] In embodiments of the present invention, such as Figure 1 As shown, the original milling dust removal system included a fan 1, a cyclone separator 2, a crusher 3, and a milling machine 4. Due to poor dust removal efficiency, it failed to meet requirements and was therefore improved and innovated. The improved milling dust removal system is shown below. Figure 2 The system includes a fan 1, a cyclone separator 2, a crusher 3, a milling machine 4, an airlock dust removal device 5, and a membrane 6 for adsorbing aluminum dust. The airlock dust removal device 5 is located below the cyclone separator 2, and the membrane 6 for adsorbing aluminum dust is installed in the pipe connected to the fan 1. See [link to relevant documentation] for the actual application scenario of the improved milling dust removal system. Figure 4-6 .

[0056] The present invention relates to a negative pressure dust removal design and manufacturing method for a multi-specification double-sided milling machine, comprising the following steps:

[0057] (1) Milling operation of milling machine

[0058] Function: The machine uses a cutter head to mill large surfaces of aluminum ingots to produce fine aluminum strips.

[0059] Process parameters:

[0060] Aluminum ingot dimensions: 6200mm×495mm×1060mm;

[0061] Cutting parameters: linear speed 500-3000 mm / min, feed rate: 10 mm;

[0062] Specifications of milled product (thin aluminum strip): length approximately 1m, width approximately 10mm, thickness approximately 3mm.

[0063] (2) Crushing process by crusher

[0064] Function: To break up the thin aluminum strips produced by milling, generating short chips and aluminum dust.

[0065] Process parameters:

[0066] Input material (thin aluminum strip) specifications: length approximately 1m, width approximately 10mm, thickness approximately 3mm;

[0067] Specifications of the crushed product: The length of the fragments is approximately 20mm;

[0068] Accompanying products (aluminum dust): Particle diameter range 1-100μm.

[0069] (3) Duct delivery

[0070] Function: It draws aluminum shavings and aluminum dust generated by the crusher into the cyclone separator to realize material transfer.

[0071] Process parameters:

[0072] Conveying medium: Aluminum shavings approximately 20mm in length + aluminum dust with a diameter of 1-100μm;

[0073] Conveying path: From the crusher outlet, it is connected to the cyclone separator inlet via an air duct.

[0074] (4) Cyclone separator separation operation

[0075] Function: Uses cyclone separation to separate large aluminum shavings, achieving preliminary solid-gas separation.

[0076] Process parameters:

[0077] Separation target: Large aluminum shavings (mainly fragments about 20mm in length);

[0078] Separation results: Large aluminum shavings are separated and collected by a conveyor belt, while the remaining gas carries unseparated aluminum dust (1-100μm in diameter) into the next stage.

[0079] (5) Fan suction and conveying

[0080] Function: Provides negative pressure power to pump and transport materials and gases.

[0081] Process parameters:

[0082] Suction Target 1: Thin aluminum strips (approximately 1m in length) produced by the milling equipment are conveyed to the crusher (preceding equipment).

[0083] Target 2: Gas and aluminum dust (diameter 1-100μm) separated by the cyclone separator are drawn out to the outdoor discharge stage.

[0084] (6) Emission filtration treatment

[0085] Function: To filter the gas delivered by the fan to achieve compliant emissions.

[0086] Process parameters:

[0087] Treatment method: Through membrane filtration installed in the pipeline to adsorb aluminum dust;

[0088] Emissions: Clean gas after passing through a membrane filter used to adsorb aluminum dust (removing aluminum dust with a diameter of 1-100μm).

[0089] Cyclone separator size unit Diameter a on the box 155 cm Box height b+c 200 cm Feed port length f 282 cm Feed port diameter e 90 cm Box bottom diameter 90 cm Hopper height g 370 cm

[0090] Remark:

[0091] 1. Material type: Aluminum dust;

[0092] 2. The cyclone separator is a circular structure, located indoors, 4m away from the wall;

[0093] The final fan selected for this invention has a power rating of 110KW and an air volume of 30,000 m³ / h. 3 / h, wind pressure 7200-7500pa, can achieve negative pressure dust removal.

[0094] The method for preparing the membrane for adsorbing aluminum dust includes the following steps:

[0095] (1) Raw material pretreatment

[0096] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60-80℃ for 4-6 hours to remove moisture;

[0097] 2) Activate the aluminum-based adsorbent at 100-120℃ for 2-3 hours to enhance its adsorption activity;

[0098] (2) Mixed dispersion

[0099] 1) Dissolve 25-35 parts of polylactic acid in 30-50 mL of ethyl acetate, and then emulsify it with 50-80 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at a high speed of 2000-3000 r / min for 10-15 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol to sodium dodecylbenzene sulfonate is (2-5):(0.5-2).

[0100] 2) Add 20-35 parts of aluminum-based adsorbent, 5-10 parts of nano-silica, 3-8 parts of graphene oxide, and 1-3 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 500-1000 r / min for 30-60 min to obtain mixture a.

[0101] (3) Crosslinking reaction

[0102] Add 1-3 parts chitosan, 0.5-2 parts glutaraldehyde and 0.1-1 parts citric acid to mixture a, adjust the pH to 4-6, and then react at 40-60℃ for 2-4 hours to obtain mixture b;

[0103] (4) Film-forming treatment

[0104] Pour the mixture b into a flat mold, control the thickness to 50-100 micrometers, and dry it at 50-70℃ for 12-24 hours to form a wet film;

[0105] (5) Surface modification

[0106] The wet film is immersed in an ethanol solution of 0.1-1% nano zinc oxide by mass concentration, and ultrasonically treated for 10-15 minutes at an ultrasonic power of 300-500W and a frequency of 20-40kHz to form an antibacterial coating. Then it is taken out and dried at room temperature for 2-4 hours to obtain the dried film.

[0107] (6) Heating treatment

[0108] The dried membrane is heated to 100-120℃ at a rate of 2-5℃ / min and held at that temperature for 1.5-2 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0109] The preparation method of the aluminum-based adsorbent includes the following steps:

[0110] (1) Sol preparation

[0111] Raw material mixing: By mass, dissolve 30-40 parts of aluminum nitrate trihydrate, 12-18 parts of citric acid, and 10-15 parts of polyethylene glycol in 30-40 mL of deionized water and 15-20 mL of ethanol. React at a stirring speed of 500-800 r / min and a temperature of 40-60℃ for 2-3 hours to form a transparent sol.

[0112] pH adjustment: Adjust the pH of the sol to 4.5-5.5 with ammonia water to obtain the pH-adjusted sol;

[0113] (2) Gel molding

[0114] Chitosan addition: Dissolve 2-4 parts of chitosan in 40-50 mL of 1-1.3% acetic acid solution, and then stir at 48-52℃ for 1-1.2 h to assist dissolution and obtain a uniform gel;

[0115] Foaming treatment: Add 6-10 parts ammonium bicarbonate and 0.1-0.3 parts Tween-80 to the homogeneous gel, and react for 30-60 minutes at a temperature of 30-35℃ and a stirring speed of 300-500 r / min to generate bubbles and form a porous precursor.

[0116] (3) Hydrothermal crystallization

[0117] Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 120-150℃ for 12-24 hours to promote Al crystallization. 3+ Growth of coordination networks with citric acid;

[0118] Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash with deionized water and ethanol alternately 3-5 times to remove unreacted impurities and obtain the product;

[0119] (4) Calcination activation

[0120] Template removal: The product is heated to 300-320℃ in a nitrogen atmosphere at a rate of 3-5℃ / min and held for 2-2.5h to decompose polyethylene glycol and ammonium bicarbonate, forming products with mesoporous and macroporous structures.

[0121] Surface modification: The cooled product with mesoporous and macroporous structures is soaked in an ethanol solution of 3-aminopropyltriethoxysilane with a mass concentration of 0.3-0.5% for 1.5-2 hours, then dried at 47-52℃, and amino groups are reintroduced to obtain an aluminum-based adsorbent.

[0122] The principle of the preparation technology of the membrane for adsorbing aluminum dust in this invention:

[0123] I. The specific role of each preparation step

[0124] 1. Raw material pretreatment

[0125] Drying polylactic acid, graphene oxide, and bamboo charcoal fiber at 60-80℃ for 4-6 hours can effectively remove moisture from the raw materials. The presence of moisture can interfere with the interaction between the raw materials during subsequent mixing and dispersion processes, such as affecting the stability of the emulsion, and may also form defects such as bubbles after film formation, reducing film performance. Drying ensures that these raw materials can fully play their role in subsequent steps.

[0126] Activating aluminum-based adsorbents at 100-120℃ for 2-3 hours can break the inert layer on their surface, increase the number of surface active sites, improve the adsorption affinity for aluminum dust, and thus enhance their adsorption activity.

[0127] 2. Mixing and dispersing

[0128] Polylactic acid (PLA) is dissolved in ethyl acetate in a specific ratio, and then emulsified at high speed with an aqueous solution containing polyvinyl alcohol (PVA) and sodium dodecylbenzenesulfonate (SOB) to form a W / O emulsion. The PVA and SOB are mixed at a mass ratio of (2-5):(0.5-2) to exert a synergistic emulsifying effect, reducing the oil-water interfacial tension and allowing the aqueous phase to be uniformly dispersed in the oil phase as tiny droplets, forming a stable emulsion system that provides a good carrier for the uniform dispersion of other raw materials. High-speed emulsification at 2000-3000 r / min and a time of 10-15 min ensures the stability and uniformity of the emulsion.

[0129] Adding aluminum-based adsorbent, nano-silica, graphene oxide, and bamboo charcoal fiber to a W / O emulsion and stirring at 500-1000 rpm for 30-60 minutes ensures that these solid raw materials are fully dispersed in the emulsion, preventing agglomeration. This guarantees their uniform distribution within the membrane, laying the foundation for excellent membrane performance.

[0130] 3. Crosslinking reaction

[0131] Add 1-3 parts chitosan, 0.5-2 parts glutaraldehyde, and 0.1-1 parts citric acid to mixture a, adjust the pH to 4-6, and react at 40-60℃ for 2-4 hours. The amino groups in the chitosan molecules can undergo cross-linking reactions with the aldehyde groups of glutaraldehyde, and citric acid can also participate in cross-linking, forming a three-dimensional network structure. This enhances the mechanical strength and chemical stability of the membrane, preventing dissolution or damage during use. Specific pH and temperature conditions ensure the smooth progress and appropriate degree of the cross-linking reaction.

[0132] 4. Film-forming treatment

[0133] Pour mixture b into a flat mold, controlling the thickness to 50-100 micrometers, and dry at 50-70℃ for 12-24 hours to form a wet film. Controlling the thickness ensures the uniformity of the film and the adsorption efficiency during use; too thick a film will result in a slow adsorption rate, while too thin a film may lack strength. Drying at this temperature and time allows for slow solvent removal, preventing defects such as cracking and wrinkling caused by excessively rapid drying.

[0134] 5. Surface modification

[0135] The wet membrane is immersed in an ethanol solution containing 0.1-1% nano-zinc oxide and treated under specific ultrasonic conditions for 10-15 minutes. The nano-zinc oxide forms an antibacterial coating on the membrane surface, imparting antibacterial properties and preventing bacterial growth from clogging the pores and affecting adsorption efficiency during use. Ultrasonic treatment ensures uniform adhesion of the nano-zinc oxide to the membrane surface, enhancing the bonding between the coating and the membrane. Drying at room temperature for 2-4 hours allows the ethanol to evaporate, fixing the antibacterial coating.

[0136] 6. Heating treatment

[0137] The dried membrane is heated to 100-120℃ at a rate of 2-5℃ / min and held at this temperature for 1.5-2 hours. Slow heating avoids internal stress caused by a sudden temperature rise, which could lead to cracking. Holding the membrane at this temperature further promotes intermolecular interactions within the membrane, such as enhancing the stability of the cross-linked structure, thereby significantly increasing the membrane's mechanical strength. After natural cooling, the membrane's performance becomes even more stable.

[0138] II. Synergistic Effects Between Raw Materials

[0139] 1. Polylactic acid, as the matrix material of the membrane, has good film-forming properties and biocompatibility, providing a supporting framework for other raw materials, enabling aluminum-based adsorbents, graphene oxides, bamboo charcoal fibers, etc. to be uniformly distributed in the membrane.

[0140] 2. Graphene oxide possesses abundant oxygen-containing functional groups and a large specific surface area, while bamboo charcoal fiber also has a porous structure. Together with the aluminum-based adsorbent, they work synergistically. The aluminum-based adsorbent provides the main adsorption active sites, while the porous structures of graphene oxide and bamboo charcoal fiber serve as adsorption channels, increasing the contact opportunities between aluminum dust and the adsorption sites. All three factors contribute to improving the membrane's adsorption capacity and rate for aluminum dust.

[0141] 3. Nano-silica can fill the pores of the membrane and combine with the polylactic acid matrix to enhance the mechanical strength and wear resistance of the membrane. At the same time, the hydroxyl groups on its surface can interact with other raw materials to further stabilize the structure of the membrane.

[0142] 4. The network structure formed by the cross-linking reaction of chitosan, glutaraldehyde, and citric acid tightly binds all the above raw materials together, which not only enhances the overall stability of the membrane but also prevents the raw materials from falling off during use and extends the service life of the membrane.

[0143] 5. The antibacterial coating formed by nano zinc oxide can inhibit the growth and reproduction of bacteria on the membrane surface, prevent bacteria from clogging the membrane pores, ensure the unobstructed adsorption channels of aluminum dust, and work synergistically with other adsorption materials to maintain the long-term high-efficiency adsorption performance of the membrane.

[0144] The synergistic effect among these raw materials significantly improves the adsorption capacity, mechanical strength, antibacterial properties, and service life of the prepared membrane, achieving unexpected technical effects that are superior to those of a single raw material.

[0145] III. The Necessity and Importance of Optimizing Process Parameters

[0146] 1. Raw material pretreatment parameters: If the drying temperature is too low or the drying time is too short, the moisture in the raw materials cannot be completely removed, affecting the subsequent mixing, dispersion, and cross-linking reactions. If the temperature is too high, raw materials such as polylactic acid may degrade. Inappropriate activation temperature and time for aluminum-based adsorbents will result in insufficient active sites, reducing adsorption performance. Optimizing these parameters ensures the raw materials are in their optimal state.

[0147] 2. Mixing and Dispersion Parameters: Insufficient emulsification speed and time prevent the formation of a stable W / O emulsion, resulting in uneven raw material dispersion and variations in membrane performance. Excessive speed may disrupt the emulsion system. Inappropriate stirring speed and time can cause solid raw materials to agglomerate, failing to disperse evenly in the emulsion and affecting the overall membrane performance. Optimizing these parameters ensures uniform raw material dispersion, laying the foundation for excellent membrane performance.

[0148] 3. Crosslinking reaction parameters: An unsuitable pH value can affect the extent of the crosslinking reaction; insufficient reaction temperature and time will result in incomplete crosslinking, leading to poor membrane strength and stability; excessive reaction may reduce membrane porosity and affect adsorption performance. Optimizing these parameters can bring the crosslinking reaction to an ideal state.

[0149] 4. Film Formation Processing Parameters: Inappropriate film thickness can affect its adsorption efficiency and mechanical strength, while improper drying temperature and time can lead to film defects. Optimizing these parameters can ensure the stability of the film's morphology and performance.

[0150] 5. Surface Modification Parameters: Excessive concentration of the nano-zinc oxide solution can clog the membrane pores; insufficient concentration will result in poor antibacterial effect. Inappropriate ultrasonic power, frequency, and treatment time can affect the adhesion of nano-zinc oxide to the membrane surface. Optimizing these parameters will allow the antibacterial coating to perform at its best.

[0151] 6. Heating parameters: Excessive heating rate can cause internal stress in the membrane, leading to cracking; inappropriate holding temperature and time will prevent the membrane from achieving its mechanical strength enhancement effect. Optimizing these parameters ensures an effective improvement in the membrane's mechanical strength.

[0152] In summary, the various process parameters influence and constrain each other. Only by optimizing them can each preparation step be performed at its best, resulting in a high-performance, stable, and reliable membrane for adsorbing aluminum dust, achieving unexpected and excellent technical results. Inappropriate process parameters may lead to a decline in membrane performance or even prevent it from meeting usage requirements.

[0153] The principle of the preparation technology of the aluminum-based adsorbent of the present invention:

[0154] Detailed analysis of the preparation method of aluminum-based adsorbents

[0155] I. The specific role of each preparation step

[0156] 1. Sol preparation

[0157] Raw material mixing: Dissolve 30-40 parts aluminum nitrate trihydrate, 12-18 parts citric acid, and 10-15 parts polyethylene glycol in 30-40 mL of deionized water and 15-20 mL of ethanol, and react at a specific stirring speed and temperature to form a transparent sol. During this process, aluminum nitrate trihydrate acts as an aluminum source, dissociating into Al in the solvent. 3+ Citric acid will react with Al 3+ A complexation reaction occurs, forming a stable aluminum-citric acid complex. Polyethylene glycol dissolves in the mixed solvent, and the steric hindrance of its molecular chains ensures the uniform dispersion of the aluminum-citric acid complex, preventing agglomeration and laying the foundation for the subsequent formation of a homogeneous sol system. Simultaneously, appropriate stirring speed (500-800 r / min) and temperature (40-60℃) promote the complete dissolution and reaction of the raw materials. A reaction time of 2-3 hours ensures the complete completion of the complexation reaction, resulting in a stable, transparent sol.

[0158] pH Adjustment: Adjust the pH of the sol to 4.5-5.5 using ammonia. This step is to adjust the pH of the sol to ensure the stability of the aluminum-citric acid complex within this pH range. If the pH is too low, the complex will dissociate; if the pH is too high, it may cause Al... 3+ Hydrolysis occurs, forming aluminum hydroxide precipitate, which disrupts the stability of the sol system. The adjusted pH environment creates suitable conditions for subsequent gel formation.

[0159] 2. Gel formation

[0160] Chitosan addition: Dissolve 2-4 parts of chitosan in 40-50 mL of a 1-1.3% acetic acid solution and stir at 48-52℃ for 1-1.2 h to aid dissolution and obtain a homogeneous gel. Chitosan swells and dissolves in the acetic acid solution, forming a colloid with a certain viscosity. The temperature of 48-52℃ and the stirring time of 1-1.2 h help the chitosan to dissolve fully and form a homogeneous system. After mixing this homogeneous gel with the previously prepared sol, the chitosan molecular chains can interact with aluminum-citric acid complexes, increasing the viscosity of the system and providing a framework support for the subsequent foaming to form a porous structure.

[0161] Foaming treatment: Add 6-10 parts ammonium bicarbonate and 0.1-0.3 parts Tween-80 to the homogeneous gel. Under specific temperature and stirring speed, the reaction generates bubbles to form a porous precursor. Under these reaction conditions, ammonium bicarbonate decomposes to produce carbon dioxide gas. Tween-80, as a surfactant, reduces the gas-liquid interfacial tension, making the generated bubbles more stable and less prone to coalescence and collapse, thus forming a large number of uniformly distributed pores in the gel system. A temperature of 30-35℃ and a stirring speed of 300-500 r / min ensure both the decomposition rate of ammonium bicarbonate and the uniform dispersion of bubbles in the system, ultimately forming a precursor with a porous structure. This is crucial for improving the specific surface area and adsorption performance of subsequent aluminum-based adsorbents.

[0162] 3. Hydrothermal crystallization

[0163] Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 120-150℃ for 12-24 hours. The hydrothermal environment was Al. 3+ The growth of coordination networks with citric acid provides favorable conditions. High temperature and pressure promote molecular diffusion and reactions, allowing the coordination network to gradually grow and crystallize, forming a more stable crystal structure. This process enhances the structural stability of the adsorbent, while the formation of the crystal structure also helps to preserve and improve the porous structure.

[0164] Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash alternately with deionized water and ethanol 3-5 times. Natural cooling avoids sudden temperature changes that could cause crystal structure breakage; centrifugation quickly separates the product; and alternating washing effectively removes unreacted raw materials, impurity ions, etc., improving product purity and preventing impurities from adversely affecting subsequent adsorption performance.

[0165] 4. Calcination activation

[0166] Template removal: The product is heated to 300-320℃ in a nitrogen atmosphere at a rate of 3-5℃ / min and held for 2-2.5 hours. The nitrogen atmosphere prevents the product from being oxidized at high temperatures. Slow heating (3-5℃ / min) avoids structural damage caused by rapid temperature changes. The temperature of 300-320℃ and the holding time of 2-2.5 hours allow for the complete decomposition and removal of polyethylene glycol and ammonium bicarbonate, while simultaneously forming mesoporous and macroporous structures within the product. These pore structures significantly increase the specific surface area of ​​the adsorbent, providing more active sites for the adsorption process.

[0167] Surface modification: The cooled product was immersed in an ethanol solution of 0.3-0.5% (w / w) 3-aminopropyltriethoxysilane for 1.5-2 hours, followed by drying at 47-52°C. The amino group in 3-aminopropyltriethoxysilane reacts with the hydroxyl group on the product surface, thereby introducing the amino group onto the adsorbent surface. The amino group has a strong adsorption capacity and can interact with many substances to be adsorbed, significantly improving the adsorption performance of the adsorbent. The drying temperature of 47-52°C removes the ethanol solvent while ensuring the stable binding of the amino group on the adsorbent surface.

[0168] II. Synergistic effects between raw materials and their performance enhancement

[0169] 1. Synergistic effect of aluminum source and complexing agent: Aluminum nitrate trihydrate provides Al 3+ A stable aluminum-citric acid complex is formed with citric acid, which is uniformly dispersed in the sol system. The addition of polyethylene glycol further stabilizes the complex through steric hindrance. The synergistic effect of these three components makes the sol system more stable and uniform, laying the foundation for the subsequent formation of a uniform gel and crystal structure. This is beneficial to the uniformity of the final product structure, thereby improving the stability of the adsorption performance.

[0170] 2. Synergistic effect of chitosan with foaming agents and surfactants: The gel formed by chitosan provides the framework structure for the entire system. Bubbles generated from the decomposition of ammonium bicarbonate, under the stabilizing effect of Tween-80, can be uniformly distributed within the chitosan gel framework, forming a large number of porous structures. The framework effect of chitosan ensures the stability of the porous structure, while the porous structure significantly increases the specific surface area of ​​the adsorbent. The synergistic effect of these three factors gives the adsorbent abundant pores, providing more channels and spaces for the adsorbed substances, and significantly improving the adsorption capacity.

[0171] 3. Synergistic effect of template agent and surface modifier: Polyethylene glycol and ammonium bicarbonate are decomposed and removed during calcination, forming mesoporous and macroporous structures. These pores provide channels for the entry and reaction of 3-aminopropyltriethoxysilane, allowing the amino groups to be more uniformly and fully loaded on the adsorbent surface. Simultaneously, the abundant pore structure and the synergistic effect of the surface amino groups not only capture substances through the physical adsorption of the pores but also enhance the adsorption capacity of the target substances through the chemical adsorption of the amino groups. The combined effect of these two factors unexpectedly improves the adsorption performance of the aluminum-based adsorbent.

[0172] III. The Necessity, Importance, and Technical Effects of Optimizing Process Parameters

[0173] 1. Stirring Speed: During the raw material mixing stage, a stirring speed of 500-800 rpm ensures thorough mixing and reaction of the raw materials, preventing uneven reaction caused by excessively high local concentrations. If the stirring speed is too low, the raw materials will not mix sufficiently, affecting the stability of the sol; if it is too high, excessive solvent evaporation may occur, which is also detrimental to the sol system. Optimized stirring speed ensures the uniformity of the sol, providing a good foundation for subsequent processes.

[0174] 2. Temperature: Temperature parameters for each step were optimized. A temperature of 40-60℃ during raw material mixing promoted dissolution and complexation reactions; a temperature of 48-52℃ during chitosan dissolution ensured complete dissolution; a temperature of 30-35℃ during foaming allowed ammonium bicarbonate to decompose at a suitable rate, facilitating bubble formation and stabilization; a temperature of 120-150℃ during hydrothermal crystallization promoted crystal growth; and the temperatures for calcination and drying were precisely controlled to ensure effective template removal and surface modification. Appropriate temperature parameters ensured that each reaction step proceeded as expected; improper temperatures could lead to incomplete reactions, structural damage, and other problems. Optimized temperature parameters resulted in superior product structure and properties, such as a more complete crystal structure and richer porous structure.

[0175] 3. Time: The reaction time of each step is also crucial for optimization. A 2-3 hour mixing reaction of raw materials ensures complete complexation; 1-1.2 hours of chitosan stirring ensures complete dissolution; 30-60 minutes of foaming allows for sufficient bubble formation; 12-24 hours of crystallization promotes crystal growth; 2-2.5 hours of calcination and holding ensures thorough template removal; and 1.5-2 hours of surface modification soaking ensures sufficient amino loading. Sufficient reaction time ensures complete reaction, but excessive time reduces production efficiency and increases costs. Optimized time parameters improve production efficiency and reduce costs while ensuring complete reaction.

[0176] 4. pH value: Adjusting the pH of the sol to 4.5-5.5 is crucial for ensuring its stability. A suitable pH value avoids Al... 3+The hydrolysis and dissociation of the complexes ensured the smooth progress of subsequent gel formation. If the pH value is outside this range, the sol-gel system may be disrupted, preventing the formation of the desired gel structure. Optimized pH parameters ensured the stability of the entire preparation process, ultimately resulting in stable product properties.

[0177] By optimizing various process parameters, the prepared aluminum-based adsorbent exhibits superior performance, such as a significantly increased specific surface area, improved adsorption capacity, faster adsorption rate, and enhanced selectivity for target substances. These unexpected technical effects make this aluminum-based adsorbent have broader application prospects in fields such as gas adsorption. Simultaneously, the optimized process parameters also improve production stability and efficiency, reduce production costs, and possess significant practical application value.

[0178] To make the present invention more fully disclosed, more specific embodiments are described below.

[0179] I. Implementation Examples

[0180] Example 1

[0181] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine includes the following steps:

[0182] (1) Milling operation of milling machine

[0183] Function: The machine uses a cutter head to mill large surfaces of aluminum ingots to produce fine aluminum strips.

[0184] (2) Crushing process by crusher

[0185] Function: To break up the thin aluminum strips produced by milling, generating short chips and aluminum dust.

[0186] (3) Duct delivery

[0187] Function: It draws aluminum shavings and aluminum dust generated by the crusher into the cyclone separator to realize material transfer.

[0188] Conveying path: From the crusher outlet, it is connected to the cyclone separator inlet via an air duct.

[0189] (4) Cyclone separator separation operation

[0190] Function: Uses cyclone separation to separate large aluminum shavings, achieving preliminary solid-gas separation.

[0191] Process parameters:

[0192] Target to be separated: large aluminum shavings;

[0193] Separation results: Large aluminum shavings are separated and collected by a conveyor belt, while the remaining gas carries unseparated aluminum dust (1-100μm in diameter) into the next stage.

[0194] (5) Fan suction and conveying

[0195] Function: Provides negative pressure power to pump and transport materials and gases.

[0196] Process parameters:

[0197] Suction Target 1: Fine aluminum strips produced by the milling equipment are conveyed to the crusher (preceding equipment).

[0198] Target 2: Gas and aluminum dust (diameter 1-100μm) separated by the cyclone separator are drawn out to the outdoor discharge stage.

[0199] (6) Emission filtration treatment

[0200] Function: To filter the gas delivered by the fan to achieve compliant emissions.

[0201] Process parameters:

[0202] Treatment method: Through membrane filtration installed in the pipeline to adsorb aluminum dust;

[0203] Emissions: Clean gas after passing through a membrane filter used to adsorb aluminum dust (removing aluminum dust with a diameter of 1-100μm).

[0204] The method for preparing the membrane for adsorbing aluminum dust includes the following steps:

[0205] (1) Raw material pretreatment

[0206] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 70℃ for 5 hours to remove moisture;

[0207] 2) Activate the aluminum-based adsorbent at 110℃ for 2.5h to enhance its adsorption activity;

[0208] (2) Mixed dispersion

[0209] 1) Dissolve 30 parts of polylactic acid in 40 mL of ethyl acetate, and then emulsify it with 65 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at 2500 r / min for 12 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol and sodium dodecylbenzene sulfonate is 3:1.

[0210] 2) Add 25 parts of aluminum-based adsorbent, 7 parts of nano-silica, 5 parts of graphene oxide, and 2 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 750 r / min for 45 min to obtain mixture a;

[0211] (3) Crosslinking reaction

[0212] Add 2 parts chitosan, 1 part glutaraldehyde and 0.5 parts citric acid to mixture a, adjust the pH to 5, and then react at 50°C for 3 hours to obtain mixture b;

[0213] (4) Film-forming treatment

[0214] Pour the mixture b into a flat mold, control the thickness to 75 micrometers, and dry it at 60°C for 18 hours to form a wet film;

[0215] (5) Surface modification

[0216] The wet film was immersed in an ethanol solution of 0.5% nano zinc oxide and ultrasonically treated for 12 minutes at an ultrasonic power of 400W and a frequency of 30kHz to form an antibacterial coating. Then it was taken out and dried at room temperature for 3 hours to obtain the dried film.

[0217] (6) Heating treatment

[0218] The dried membrane is heated to 110°C at a rate of 3°C / min and held at that temperature for 1.7 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0219] The preparation method of the aluminum-based adsorbent is as follows:

[0220] (1) Sol preparation

[0221] Raw material mixing: In parts by weight, dissolve 35 parts aluminum nitrate trihydrate, 15 parts citric acid, and 12 parts polyethylene glycol in 35 mL of deionized water and 17 mL of ethanol, and react at a stirring speed of 650 r / min and a temperature of 50℃ for 2.5 h to form a transparent sol.

[0222] pH adjustment: Adjust the pH of the sol to 5.0 with ammonia water to obtain the pH-adjusted sol;

[0223] (2) Gel molding

[0224] Chitosan addition: Dissolve 3 parts of chitosan in 45 mL of 1.15% acetic acid solution, and then stir at 50℃ for 1.1 h to assist dissolution and obtain a uniform gel;

[0225] Foaming treatment: Add 8 parts ammonium bicarbonate and 0.2 parts Tween-80 to the uniform gel, and react for 45 min at 32℃ and 400 r / min to generate bubbles and form a porous precursor.

[0226] (3) Hydrothermal crystallization

[0227] Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 135°C for 18 hours to promote Al crystallization. 3+Growth of coordination networks with citric acid;

[0228] Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash four times alternately with deionized water and ethanol to remove unreacted impurities and obtain the product;

[0229] (4) Calcination activation

[0230] Template removal: The product was heated to 310℃ at 4℃ / min in a nitrogen atmosphere and held for 2.2h to decompose polyethylene glycol and ammonium bicarbonate, forming products with mesoporous and macroporous structures;

[0231] Surface modification: The cooled product with mesoporous and macroporous structures was soaked in an ethanol solution of 0.4% 3-aminopropyltriethoxysilane for 1.7 h, then dried at 50 °C, and amino groups were reintroduced to obtain an aluminum-based adsorbent.

[0232] Example 2

[0233] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine. The preparation process is basically the same as in Example 1, except that the preparation method of the membrane used to adsorb aluminum dust is different, including the following steps:

[0234] (1) Raw material pretreatment

[0235] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60℃ for 6 hours to remove moisture;

[0236] 2) Activate the aluminum-based adsorbent at 100℃ for 3 hours to enhance its adsorption activity;

[0237] (2) Mixed dispersion

[0238] 1) Dissolve 25 parts of polylactic acid in 30 mL of ethyl acetate, and then emulsify it with 50 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at 2000 r / min for 15 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol to sodium dodecylbenzene sulfonate is 2:0.5.

[0239] 2) Add 20 parts of aluminum-based adsorbent, 5 parts of nano-silica, 3 parts of graphene oxide, and 1 part of bamboo charcoal fiber to the W / O type emulsion, and stir at 500 r / min for 60 min to obtain mixture a.

[0240] (3) Crosslinking reaction

[0241] Add 1 part chitosan, 0.5 parts glutaraldehyde and 0.1 parts citric acid to mixture a, adjust the pH to 4, and then react at 40°C for 4 hours to obtain mixture b;

[0242] (4) Film-forming treatment

[0243] Pour the mixture b into a flat mold, control the thickness to 50 micrometers, and dry it at 50°C for 24 hours to form a wet film;

[0244] (5) Surface modification

[0245] The wet film was immersed in an ethanol solution of 0.1% nano zinc oxide and ultrasonically treated for 15 minutes at an ultrasonic power of 300W and a frequency of 20kHz to form an antibacterial coating. Then it was taken out and dried at room temperature for 4 hours to obtain the dried film.

[0246] (6) Heating treatment

[0247] The dried membrane is heated to 100°C at a rate of 2°C / min and held at that temperature for 2 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0248] The preparation method of the aluminum-based adsorbent is as follows:

[0249] (1) Sol preparation

[0250] Raw material mixing: In parts by weight, dissolve 30 parts aluminum nitrate trihydrate, 12 parts citric acid, and 10 parts polyethylene glycol in 30 mL of deionized water and 15 mL of ethanol, and react at a stirring speed of 500 r / min and a temperature of 40℃ for 3 h to form a transparent sol.

[0251] pH adjustment: Adjust the pH of the sol to 4.5 with ammonia water to obtain the pH-adjusted sol;

[0252] (2) Gel molding

[0253] Chitosan addition: Dissolve 2 parts of chitosan in 40 mL of 1% acetic acid solution, and then stir at 48℃ for 1.2 h to assist dissolution and obtain a uniform gel;

[0254] Foaming treatment: Add 6 parts ammonium bicarbonate and 0.1 parts Tween-80 to the uniform gel, and react for 60 min at 30℃ and 300 r / min to generate bubbles and form a porous precursor.

[0255] (3) Hydrothermal crystallization

[0256] Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 120°C for 24 hours to promote Al crystallization. 3+ Growth of coordination networks with citric acid;

[0257] Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash three times alternately with deionized water and ethanol to remove unreacted impurities and obtain the product;

[0258] (4) Calcination activation

[0259] Template removal: The product is heated to 300℃ at 3℃ / min in a nitrogen atmosphere and held for 2.5h to decompose polyethylene glycol and ammonium bicarbonate, forming products with mesoporous and macroporous structures;

[0260] Surface modification: The cooled product with mesoporous and macroporous structures was soaked in an ethanol solution of 0.3% 3-aminopropyltriethoxysilane for 2 hours, then dried at 47°C, and amino groups were reintroduced to obtain an aluminum-based adsorbent.

[0261] Example 3

[0262] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine. The preparation process is basically the same as in Example 1, except that the preparation method of the membrane used to adsorb aluminum dust is different, including the following steps:

[0263] (1) Raw material pretreatment

[0264] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 80℃ for 4 hours to remove moisture;

[0265] 2) Activate the aluminum-based adsorbent at 120℃ for 2 hours to enhance its adsorption activity;

[0266] (2) Mixed dispersion

[0267] 1) Dissolve 35 parts of polylactic acid in 50 mL of ethyl acetate, and then emulsify it with 80 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at 3000 r / min for 10 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol and sodium dodecylbenzene sulfonate is 5:2.

[0268] 2) Add 30 parts of aluminum-based adsorbent, 10 parts of nano-silica, 8 parts of graphene oxide, and 3 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 1000 r / min for 30 min to obtain mixture a.

[0269] (3) Crosslinking reaction

[0270] Add 3 parts chitosan, 2 parts glutaraldehyde and 1 part citric acid to mixture a, adjust the pH to 6, and then react at 60°C for 2 hours to obtain mixture b.

[0271] (4) Film-forming treatment

[0272] Pour the mixture b into a flat mold, control the thickness to 100 micrometers, and dry it at 70°C for 12 hours to form a wet film;

[0273] (5) Surface modification

[0274] The wet film was immersed in an ethanol solution of 1% nano zinc oxide and ultrasonically treated for 10 minutes at an ultrasonic power of 500W and a frequency of 40kHz to form an antibacterial coating. Then it was taken out and dried at room temperature for 2 hours to obtain the dried film.

[0275] (6) Heating treatment

[0276] The dried membrane is heated to 120°C at a rate of 5°C / min and held at that temperature for 1.5 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0277] The preparation method of the aluminum-based adsorbent is as follows:

[0278] (1) Sol preparation

[0279] Raw material mixing: In parts by weight, dissolve 40 parts aluminum nitrate trihydrate, 18 parts citric acid, and 15 parts polyethylene glycol in 40 mL of deionized water and 20 mL of ethanol, and react at a stirring speed of 800 r / min and a temperature of 60℃ for 2 h to form a transparent sol.

[0280] pH adjustment: Adjust the pH of the sol to 5.5 with ammonia water to obtain the pH-adjusted sol;

[0281] (2) Gel molding

[0282] Chitosan addition: Dissolve 4 parts of chitosan in 50 mL of 1.3% acetic acid solution, and then stir at 52℃ for 1 h to assist dissolution and obtain a uniform gel;

[0283] Foaming treatment: Add 10 parts ammonium bicarbonate and 0.3 parts Tween-80 to the uniform gel, and react for 30 min at 35℃ and 500 r / min to generate bubbles and form a porous precursor.

[0284] (3) Hydrothermal crystallization

[0285] Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 150°C for 12 hours to promote Al crystallization. 3+ Growth of coordination networks with citric acid;

[0286] Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash 5 times alternately with deionized water and ethanol to remove unreacted impurities and obtain the product;

[0287] (4) Calcination activation

[0288] Template removal: The product was heated to 320°C at 5°C / min in a nitrogen atmosphere and held for 2 hours to decompose polyethylene glycol and ammonium bicarbonate, forming products with mesoporous and macroporous structures.

[0289] Surface modification: The cooled product with mesoporous and macroporous structures was soaked in an ethanol solution of 0.5% 3-aminopropyltriethoxysilane for 1.5 h, then dried at 52 °C, and amino groups were reintroduced to obtain an aluminum-based adsorbent.

[0290] Example 4

[0291] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine. The preparation process is basically the same as in Example 1, except that the preparation method of the membrane used to adsorb aluminum dust is different, including the following steps:

[0292] (1) Raw material pretreatment

[0293] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 65℃ for 5.5h to remove moisture;

[0294] 2) Activate the aluminum-based adsorbent at 105℃ for 2.8h to enhance its adsorption activity;

[0295] (2) Mixed dispersion

[0296] 1) Dissolve 28 parts of polylactic acid in 35 mL of ethyl acetate, and then emulsify it with 60 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at 2200 r / min for 14 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol to sodium dodecylbenzene sulfonate is 3:0.8.

[0297] 2) Add 22 parts of aluminum-based adsorbent, 6 parts of nano-silica, 4 parts of graphene oxide, and 1.5 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 600 r / min for 50 min to obtain mixture a;

[0298] (3) Crosslinking reaction

[0299] Add 1.5 parts chitosan, 0.8 parts glutaraldehyde and 0.3 parts citric acid to mixture a, adjust the pH to 4.5, and then react at 45℃ for 3.5 h to obtain mixture b;

[0300] (4) Film-forming treatment

[0301] Pour the mixture b into a flat mold, control the thickness to 60 micrometers, and dry it at 55°C for 20 hours to form a wet film;

[0302] (5) Surface modification

[0303] The wet film was immersed in an ethanol solution of 0.3% nano zinc oxide and ultrasonically treated for 14 minutes at an ultrasonic power of 350W and a frequency of 25kHz to form an antibacterial coating. Then it was taken out and dried at room temperature for 3.5 hours to obtain the dried film.

[0304] (6) Heating treatment

[0305] The dried membrane is heated to 105°C at a rate of 3°C / min and held at that temperature for 1.8 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0306] The preparation method of the aluminum-based adsorbent is the same as that of the aluminum-based adsorbent in Example 1.

[0307] Example 5

[0308] A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine. The preparation process is basically the same as in Example 1, except that the preparation method of the membrane used to adsorb aluminum dust is different, including the following steps:

[0309] (1) Raw material pretreatment

[0310] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 75℃ for 4.5h to remove moisture;

[0311] 2) Activate the aluminum-based adsorbent at 115℃ for 2.2 h to enhance its adsorption activity;

[0312] (2) Mixed dispersion

[0313] 1) Dissolve 32 parts of polylactic acid in 45 mL of ethyl acetate, and then emulsify it with 70 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at 2800 r / min for 11 min to form a W / O type emulsion. The mass ratio of polyvinyl alcohol to sodium dodecylbenzene sulfonate is 4:1.5.

[0314] 2) Add 28 parts of aluminum-based adsorbent, 9 parts of nano-silica, 7 parts of graphene oxide, and 2.5 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 900 r / min for 35 min to obtain mixture a;

[0315] (3) Crosslinking reaction

[0316] Add 2.5 parts chitosan, 1.5 parts glutaraldehyde and 0.8 parts citric acid to mixture a, adjust the pH to 5.5, and then react at 55℃ for 2.5 h to obtain mixture b;

[0317] (4) Film-forming treatment

[0318] Pour the mixture b into a flat mold, control the thickness to 90 micrometers, and dry it at 65°C for 15 hours to form a wet film;

[0319] (5) Surface modification

[0320] The wet film was immersed in an ethanol solution of 0.8% nano zinc oxide and ultrasonically treated for 11 minutes at an ultrasonic power of 450W and a frequency of 35kHz to form an antibacterial coating. Then it was taken out and dried at room temperature for 2.5 hours to obtain the dried film.

[0321] (6) Heating treatment

[0322] The dried membrane is heated to 115°C at a rate of 4°C / min and held at that temperature for 1.6 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained.

[0323] The preparation method of the aluminum-based adsorbent is the same as that of the aluminum-based adsorbent in Example 1.

[0324] II. Comparative Example

[0325] Comparative Example 1

[0326] The process is basically the same as that in Example 1, except that the amount of aluminum-based adsorbent used is 15 parts, and the other steps and parameters are the same as those in Example 1.

[0327] Comparative Example 2

[0328] The process is basically the same as that in Example 1, except that no graphene oxide is added. All other steps and parameters are the same as in Example 1.

[0329] Comparative Example 3

[0330] The process is basically the same as that in Example 1, except that the pH of the crosslinking reaction is adjusted to 3, while the other steps and parameters are the same as in Example 1.

[0331] Comparative Example 4

[0332] The process is basically the same as that in Example 1, except that the drying temperature during film formation is 40°C, while the other steps and parameters are the same as in Example 1.

[0333] Comparative Example 5

[0334] The process is basically the same as that in Example 1, except that the concentration of nano zinc oxide is 2% during surface modification. All other steps and parameters are the same as in Example 1.

[0335] Comparative Example 6

[0336] The process is basically the same as that in Example 1, except that the heating rate is 1℃ / min during the heating process. All other steps and parameters are the same as in Example 1.

[0337] III. Single-factor experiments for screening key process parameters

[0338] Process parameters level Adsorption efficiency (%) Tensile strength (MPa) Dosage of aluminum-based adsorbent (parts) 15 90.3 7.4 20 95.1 8.1 25 99.5 8.5 30 98.2 8.3 35 96.4 8.0 Polylactic acid dosage (parts) 20 94.2 7.3 25 97.1 8.0 30 99.5 8.5 35 98.3 8.2 40 96.0 7.9 pH value of cross-linking reaction 3 92.8 7.3 4 96.2 8.0 5 99.5 8.5 6 97.1 8.2 7 93.5 7.0 Film-forming drying temperature (°C) 40 93.4 7.2 50 97.0 8.0 60 99.5 8.5 70 96.4 8.2 80 92.7 7.5 Concentration of surface-modified nano zinc oxide (%) 0.05 92.6 8.0 0.1 95.1 8.2 0.5 99.5 8.5 1 97.3 8.3 1.5 94.5 8.1 Heating treatment temperature (°C) 90 94.3 7.5 100 97.2 8.0 110 99.5 8.5 120 98.1 8.3 130 95.4 7.8

[0339] Analysis of the conclusions drawn from the table above:

[0340] (1) Aluminum-based adsorbent dosage: When the dosage is less than 25 parts, there are insufficient adsorption active sites, resulting in low adsorption efficiency; when the dosage is greater than 25 parts, excessive aluminum-based adsorbent will affect the structural integrity of the membrane, causing a slight decrease in tensile strength. At the same time, particle agglomeration may affect the adsorption effect, resulting in a decrease in adsorption efficiency. The preferred dosage is 20-35 parts, and the optimal dosage is 25 parts.

[0341] (2) Polylactic acid dosage: When the dosage is too low, the film-forming properties of the membrane are poor and the structure is unstable, which affects the adsorption efficiency and mechanical strength; when the dosage is too high, the porosity of the membrane may decrease, which hinders the adsorption of aluminum dust and leads to a decrease in adsorption efficiency. The optimal dosage is 25-35 parts, and the optimal dosage is 30 parts.

[0342] (3) pH value of cross-linking reaction: When the pH value is too low, the cross-linking reaction is insufficient, the structural stability of the membrane is poor, and the mechanical strength and adsorption efficiency are both low; when the pH value is too high, some components may be hydrolyzed or precipitated, affecting the performance of the membrane. The optimal pH value is 4-6, and the optimal pH value is 5.

[0343] (4) Film drying temperature: If the temperature is too low, the drying speed is slow and too much moisture may remain in the film, affecting the structure and performance of the film; if the temperature is too high, the drying speed is too fast, which may cause cracking on the film surface or uneven internal structure, reducing adsorption efficiency and mechanical strength. The preferred temperature is 50-70℃, and the optimal temperature is 60℃.

[0344] (5) Concentration of surface-modified nano zinc oxide: If the concentration is too low, the antibacterial coating will not form sufficiently, the antibacterial effect will be poor, and the service life and adsorption stability of the membrane will be indirectly affected; if the concentration is too high, the nano zinc oxide may agglomerate, affecting the air permeability and adsorption performance of the membrane, resulting in a decrease in adsorption efficiency. The optimal concentration is 0.1-1%, and the optimal concentration is 0.5%.

[0345] (6) Heating treatment temperature: If the temperature is too low, the mechanical strength of the membrane cannot be fully enhanced; if the temperature is too high, some components of the membrane may decompose or the structure may be damaged, resulting in a decrease in both adsorption efficiency and mechanical strength. The preferred temperature is 100-120℃, and the optimal temperature is 110℃.

[0346] IV. Performance Index Testing

[0347] Test metrics and methods

[0348] (1) Adsorption efficiency: In a simulated aluminum dust environment, with a wind speed of 2 m / s and a dust concentration of 50 mg / m³, the adsorption efficiency was 2 m / s. 3Tested under the specified conditions; static adsorption saturation time and adsorption efficiency retention rate after 5 ethanol elutions were tested according to the corresponding methods.

[0349] (2) Mechanical strength: Tensile strength is tested according to GB / T1040.3-2006 standard.

[0350] (3) Environmental friendliness: Test the biodegradability of raw materials, whether they comply with EU REACH standards, and whether there is any release of heavy metals.

[0351] (4) Antibacterial properties: The inhibition rate against Escherichia coli was tested according to GB / T20944.3-2008.

[0352] project Example 1 Example 2 Example 3 Example 4 Example 5 Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Comparative Example 5 Comparative Example 6 Adsorption efficiency (%) 99.5 97.2 99.0 96.1 98.4 90.2 93.5 92.1 93.3 94.2 94.5 Static adsorption saturation time (h) 22 23 21 24 22 28 26 27 25 26 25 Adsorption efficiency retention rate (%) after 5 ethanol elutions 85.9 83.2 84.5 82.6 84.1 70.3 75.1 73.2 76.0 74.4 75.3 Tensile strength (MPa) 8.6 8.2 8.4 8.1 8.3 6.5 7.0 6.8 7.2 7.1 7.3 Environmental protection conform to conform to conform to conform to conform to conform to conform to conform to conform to conform to conform to Inhibition rate against Escherichia coli (%) 95.6 93.8 94.2 92.7 94.5 90.4 85.5 87.1 90.7 89.2 90.1

[0353] Analysis of the conclusions drawn from the table above:

[0354] (1) Adsorption efficiency: The adsorption efficiency of the examples all exceeded 96%, which was much higher than that of the comparative examples. This is because the examples adopted optimized process parameters, such as the appropriate amount of aluminum-based adsorbent to provide sufficient adsorption sites, the addition of graphene oxide to enhance the adsorption capacity, and the appropriate cross-linking reaction pH and drying temperature to ensure the good structure of the membrane, which is conducive to the adsorption of aluminum dust.

[0355] (2) Static adsorption saturation time: The saturation time of the embodiment is shorter, indicating that the membrane adsorption rate of the embodiment is faster and can reach adsorption saturation more quickly, thus improving working efficiency. This is due to the reasonable pore structure and excellent adsorption performance of the membrane.

[0356] (3) Adsorption efficiency retention rate after 5 ethanol elutions: The higher retention rate in the example indicates that the membrane of the example has better regeneration performance, can be reused more times, and reduces the cost of use. This is related to the stable structure of the membrane and the good binding between the adsorbent and the membrane.

[0357] (4) Tensile strength: The tensile strength of the embodiments is ≥8.1MPa, which meets the requirements and is higher than that of the comparative example, indicating that the membranes of the embodiments have better mechanical properties, better flexibility, and can be repeatedly folded and used. This is because the appropriate heating treatment and other processes enhance the mechanical strength of the membrane.

[0358] (5) Antibacterial properties: The example showed a higher inhibition rate against Escherichia coli, indicating superior antibacterial properties, which can effectively prevent bacterial growth and extend the service life of the membrane. This is related to the antibacterial coating formed by the appropriate concentration of nano zinc oxide during surface modification.

[0359] In summary, by optimizing key process parameters, the membrane prepared by this invention for adsorbing aluminum dust is superior to the comparative example in terms of adsorption efficiency, mechanical strength, regeneration performance, and antibacterial performance, demonstrating significant progress and proving the inventiveness and superiority of this invention.

[0360] The above description, in conjunction with specific / preferred embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

Claims

1. A method for designing and manufacturing a negative pressure dust removal system for a multi-specification double-sided milling machine, characterized in that, Includes the following steps: (1) Milling operation of milling machine The aluminum plate ingot is milled on a large surface using the equipment's cutter head to produce fine aluminum strips; (2) Crushing process by crusher The fine aluminum strips produced by milling are crushed to generate short chips and aluminum dust. (3) Ductwork delivery The aluminum shavings and dust generated by the crusher are drawn into the cyclone separator to achieve material transfer; (4) Cyclone separator separation operation Large aluminum shavings are separated by cyclone separation, achieving preliminary solid-gas separation. (5) Fan suction and conveying It provides negative pressure power to suck up and transport materials and gases; (6) Emission filtration treatment The gas transported by the fan is filtered using a membrane that adsorbs aluminum dust to achieve emissions that meet standards. The method for preparing the membrane for adsorbing aluminum dust includes the following steps: (1) Raw material pretreatment 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60-80℃ for 4-6 hours to remove moisture; 2) Activate the aluminum-based adsorbent at 100-120℃ for 2-3 hours to enhance its adsorption activity; (2) Mixed dispersion 1) Dissolve 25-35 parts of polylactic acid in 30-50 mL of ethyl acetate, and then emulsify it with 50-80 mL of an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzene sulfonate at a high speed of 2000-3000 r / min for 10-15 min to form a W / O type emulsion. 2) Add 20-35 parts of aluminum-based adsorbent, 5-10 parts of nano-silica, 3-8 parts of graphene oxide, and 1-3 parts of bamboo charcoal fiber to the W / O type emulsion, and stir at 500-1000 r / min for 30-60 min to obtain mixture a. (3) Crosslinking reaction Add 1-3 parts chitosan, 0.5-2 parts glutaraldehyde and 0.1-1 parts citric acid to mixture a, adjust the pH to 4-6, and then react at 40-60℃ for 2-4 hours to obtain mixture b; (4) Film-forming treatment Pour the mixture b into a flat mold, control the thickness to 50-100 micrometers, and dry it at 50-70℃ for 12-24 hours to form a wet film; (5) Surface modification The wet film is immersed in an ethanol solution containing nano zinc oxide and ultrasonically treated for 10-15 minutes at an ultrasonic power of 300-500W and a frequency of 20-40kHz to form an antibacterial coating. Then it is taken out and dried at room temperature for 2-4 hours to obtain the dried film. (6) Heating treatment The dried membrane is heated to 100-120℃ at a rate of 2-5℃ / min and held for 1.5-2 hours to enhance its mechanical strength. After natural cooling to room temperature, a finished membrane for adsorbing aluminum dust is obtained. The preparation method of the aluminum-based adsorbent includes the following steps: a. Sol preparation Raw material mixing: By mass, dissolve 30-40 parts of aluminum nitrate trihydrate, 12-18 parts of citric acid, and 10-15 parts of polyethylene glycol in 30-40 mL of deionized water and 15-20 mL of ethanol. React at a stirring speed of 500-800 r / min and a temperature of 40-60℃ for 2-3 hours to form a transparent sol. pH adjustment: Adjust the pH of the sol to 4.5-5.5 with ammonia water to obtain the pH-adjusted sol; b. Gel molding Chitosan addition: Dissolve 2-4 parts of chitosan in 40-50 mL of 1-1.3% acetic acid solution, and then stir at 48-52℃ for 1-1.2 h to assist dissolution and obtain a uniform gel; Foaming treatment: Add 6-10 parts ammonium bicarbonate and 0.1-0.3 parts Tween-80 to the homogeneous gel, and react for 30-60 minutes at a temperature of 30-35℃ and a stirring speed of 300-500 r / min to generate bubbles and form a porous precursor. c. Hydrothermal crystallization Crystallization conditions: The porous precursor was transferred to a polytetrafluoroethylene-lined autoclave and crystallized at 120-150℃ for 12-24 hours to promote Al crystallization. 3+ Growth of coordination networks with citric acid; Cooling treatment: Allow to cool naturally to room temperature, centrifuge, and wash with deionized water and ethanol alternately 3-5 times to remove unreacted impurities and obtain the product; d. Calcination activation Template removal: The product is heated to 300-320℃ in a nitrogen atmosphere at a rate of 3-5℃ / min and held for 2-2.5h to decompose polyethylene glycol and ammonium bicarbonate, forming products with mesoporous and macroporous structures. Surface modification: The cooled product with mesoporous and macroporous structures is soaked in an ethanol solution of 3-aminopropyltriethoxysilane with a mass concentration of 0.3-0.5% for 1.5-2 hours, then dried at 47-52℃, and amino groups are reintroduced to obtain an aluminum-based adsorbent.

2. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The dimensions of the aluminum ingot are 6200mm × 495mm × 1060mm.

3. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The aluminum plate ingot is milled on a large surface using the cutter head of the equipment. Cutting parameters: linear speed 500-3000 mm / min, feed rate: 10 mm.

4. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The fine aluminum strips produced by milling are crushed, and the resulting aluminum dust has a diameter of 1-100μm.

5. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The cyclone separator is equipped with an airlock ash discharge device below it.

6. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The conveying path for drawing aluminum chips and dust generated by the crusher into the cyclone separator is as follows: from the crusher outlet, it is connected to the cyclone separator inlet via an air duct.

7. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The selected fan has a power rating of 110KW and an air volume of 30,000 m³ / h. 3 / h, wind pressure is 7200-7500pa.

8. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The mass ratio of polyvinyl alcohol to sodium dodecylbenzenesulfonate is (2-5):(0.5-2).

9. The negative pressure dust removal design and manufacturing method for multi-specification double-sided milling equipment according to claim 1, characterized in that, The mass concentration of the nano-zinc oxide in the ethanol solution is 0.1-1%.

Images