Negative pressure dust removal design and manufacturing method for multi-specification double-face milling equipment

Abstract

The invention discloses a negative pressure dust removal design and manufacturing method for multi-specification double-face milling equipment. The method comprises the following steps: (1) milling operation of a face milling machine; (2) crushing treatment by a crusher; (3) air pipe conveying; (4) separating by a cyclone separator; (5) sucking and conveying by a fan; and (6) discharging and filtering. The dust collection structure, airflow organization and the film used for adsorbing aluminum dust are improved and innovated in a targeted mode, the dust collection efficiency and the aluminum scrap collection efficiency are improved, the production environment is improved, meanwhile, potential safety hazards caused by aluminum scrap accumulation are reduced, and the comprehensive economic benefits of enterprises are remarkably improved.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of aluminum processing, and particularly relates to a design and manufacturing method of a negative pressure dust removal of a multi-specification double-face milling equipment. BACKGROUND

[0002] In the aluminum processing and manufacturing industry, the traditional aluminum plate ingot double-face milling equipment often uses positive pressure cyclone dust removal to collect aluminum chips and fine dust. With the promotion of intelligent manufacturing and the deep application of technology, the aluminum processing industry's demand for clean production has upgraded from simple end-of-pipe treatment to whole-process control. According to the survey data of China Nonferrous Metal Processing Industry Association in 2023, as high as 92% of aluminum processing enterprises will list dust control as the core index of green manufacturing upgrade.

[0003] In the field of aluminum processing and manufacturing, aluminum plate ingot double-face milling is a core forming process, and the high-speed cutting process will produce a large amount of aluminum chips and dust particles of different particle sizes. Among them, inhalable particulate matter (PM10) with a particle size of less than 10 μm and fine particulate matter (PM2.5) with a particle size of less than 2.5 μm not only pollute the production environment, but also seriously threaten the health of operating personnel, and long-term inhalation can easily cause occupational diseases such as pneumoconiosis. The traditional aluminum plate ingot double-face milling equipment widely uses positive pressure cyclone dust removal technology. Based on the principle of centrifugal separation, the centrifugal force generated by the high-speed rotation of the airflow separates the aluminum chips and other larger particles from the airflow. Under ideal working conditions, the capture efficiency of the positive pressure cyclone dust removal equipment for particles larger than 5 μm can reach 85%-90%, but for sub-micron fine dust, its purification capacity is greatly reduced.

[0004] With the continuous improvement and strict implementation of the "Comprehensive Emission Standard of Air Pollutants" (GB 16297-1996) and local environmental protection regulations, the particulate matter emission limit of the aluminum processing industry is continuously tightened. At present, most regions require the emission concentration to be controlled at 10 mg / m 3 The key environmental protection control areas will even improve the standard to 5 mg / m 3 However, in actual operation, the positive pressure cyclone dust removal system has inherent drawbacks such as dust overflow caused by positive pressure inside the equipment, pipe dust accumulation causing secondary dust raising, and its emission concentration often exceeds the standard by 3-5 times, which is difficult to meet the current environmental protection requirements. At the same time, this system lacks effective treatment means for fine dust, and in the face of the trend of increasing cleanliness requirements for precision machining, it has gradually become a technical bottleneck for the development of the industry. Therefore, designing and manufacturing an efficient negative pressure dust removal system for multi-specification double-face milling equipment is an inevitable choice for enterprises to adapt to the development trend of the industry and achieve sustainable development.

[0005] The multi-specification double-side milling equipment is mainly used for processing large plate ingots of different specifications in the aluminum processing industry. Currently, the double-side milling equipment of the company is mainly used for processing large plate ingot equipment of 6200mm*495mm*1060mm specification. In combination with the original double-side milling equipment of the company, a positive pressure type cyclone dust removal method is adopted, which can generate a large amount of dust indoors and outdoors. The fine aluminum strips generated by the aluminum ingot after milling are sucked into the crusher by air force for crushing, and the dust and debris generated are blown into the cyclone dust removal equipment by the fan for separation, and the clean air is discharged outdoors. The problems are: a small amount of aluminum chips will fly out of the cyclone separator discharge port into the room through positive pressure blowing, which needs to be cleaned frequently; fine aluminum chips will be pressed out of the discharge port into the room through positive pressure blowing, causing high aluminum dust particle concentration in the room, and in addition, oil mist generated during milling is diffused in the room, which has a major safety hazard. SUMMARY

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

[0007] In order to achieve the above technical purposes, the application adopts the following technical scheme:

[0008] A multi-specification double-side milling equipment negative pressure dust removal design and manufacturing method, comprising the following steps:

[0009] (1) Milling operation of the milling machine

[0010] The aluminum plate ingot is milled by the cutter head of the equipment to generate fine aluminum strips;

[0011] (2) Crushing treatment of the crusher

[0012] The fine aluminum strips generated by milling are crushed to generate short debris and aluminum dust;

[0013] (3) Air pipe conveying

[0014] The aluminum chips and aluminum dust generated by the crusher are sucked into the cyclone separator to realize material transfer;

[0015] (4) Separation operation of the cyclone separator

[0016] Large particle aluminum chips are separated by cyclone separation to realize preliminary separation of solid and gas;

[0017] (5) Fan suction and conveying

[0018] Provide negative pressure power to suck and convey materials and gas;

[0019] (6) Discharge filtration treatment

[0020] The gas delivered by the fan is filtered by the membrane for adsorbing aluminum dust to realize standard discharge.

[0021] Preferably, the size of the aluminum slab ingot in step (1) is 6200mm x 495mm x 1060mm.

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

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

[0024] Preferably, a gas locking and ash discharging device is arranged below the cyclone separator in step (3).

[0025] Preferably, the conveying path in step (3) is connected from the outlet of the crusher to the inlet of the cyclone separator through a wind pipe.

[0026] Preferably, the power of the fan in step (5) is selected as 110KW, the air volume of the fan is 30000m 3 / h, and the air pressure is 7200-7500pa.

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

[0028] (1) Raw material pretreatment

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

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

[0031] (2) Mixing and dispersing

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

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

[0034] (3) Crosslinking reaction

[0035] adding 1-3 parts of chitosan, 0.5-2 parts of glutaraldehyde and 0.1-1 parts of citric acid into the mixed solution a, adjusting pH to 4-6, and then reacting at 40-60℃ for 2-4h to prepare mixed solution b;

[0036] (4) Film forming treatment

[0037] Pouring the mixed solution b into a flat plate mold, controlling the thickness to be 50-100 microns, drying at 50-70℃ for 12-24h to form a wet film;

[0038] (5) Surface modification

[0039] Soaking the wet film in an ethanol solution containing nano zinc oxide, ultrasonic treatment at 300-500W of ultrasonic power and 20-40kHz of frequency for 10-15min to form an antibacterial coating, and then taking out and drying at room temperature for 2-4h to obtain a dried film;

[0040] (6) Temperature rising treatment

[0041] Rising the temperature of the dried film to 100-120℃ at a rate of 2-5℃ / min, keeping the temperature for 1.5-2h to enhance the mechanical strength, and naturally cooling to room temperature to prepare a film product for adsorbing aluminum dust.

[0042] Preferably, the mass ratio of polyvinyl alcohol and sodium dodecyl benzene sulfonate is (2-5):(0.5-2).

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

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

[0045] (1) The present application aims to systematically optimize the dust removal process and aluminum scrap collection mechanism of the double-sided milling equipment through innovative design. According to the characteristics of the multi-specification double-sided milling equipment, the negative pressure dust removal technology of the present application comprehensively considers the cutting parameters (linear speed: 500-3000mm / min, feed amount: 10mm), workpiece size: 6200mm×495mm×1060mm. By precisely optimizing the position of the dust suction port and the pipeline direction, the dust suction port is as close as possible to the dust suction fan, all pipelines adopt ≥90 degree direction, and smooth transition is adopted at the corner, so that the system resistance loss is controlled to the minimum.

[0046] (2) The present application improves and innovates the dust suction structure, air flow organization and the film for adsorbing aluminum dust, which improves the dust removal efficiency and aluminum scrap collection efficiency. Mainly, a gas locking and ash discharging device is added below the original cyclone separator, which can prevent gas loss and collect aluminum scrap at the same time, ensuring that the dust and aluminum scrap generated in the processing area can be captured and recycled in time and efficiently.

[0047] (3) The technical design not only helps the enterprise to pass the environmental protection compliance audit smoothly, but also effectively reduces the erosion of dust on the precision machining equipment, and significantly improves the comprehensive economic benefit of the enterprise. Therefore, constructing an efficient negative pressure dust removal system has become a strategic choice for aluminum processing enterprises to break through the environmental protection bottleneck, improve core competitiveness and realize green and sustainable development. BRIEF DESCRIPTION OF DRAWINGS

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

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

[0050] Figure 3 is a schematic diagram of the structure of the cyclone separator;

[0051] Figure 4 is a first scene diagram of the multi-specification double-sided milling equipment after the negative pressure dust removal design and production;

[0052] Figure 5 is a second scene diagram of the multi-specification double-sided milling equipment after the negative pressure dust removal design and production;

[0053] Figure 6 is a third scene diagram of the multi-specification double-sided milling equipment after the negative pressure dust removal design and production. DETAILED DESCRIPTION

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

[0055] In the embodiment of the application, as shown in Figure 1 , the original milling surface dust removal system includes a fan 1, a cyclone separator 2, a crusher 3, and a milling surface machine 4. Due to poor dust removal effect, it cannot meet the requirements, and improvement and innovation are made. The improved milling surface dust removal system is shown in Figure 2 , which includes a fan 1, a cyclone separator 2, a crusher 3, a milling surface machine 4, a gas locking and ash unloading device 5, and a film 6 for adsorbing aluminum dust. The gas locking and ash unloading device 5 is arranged below the cyclone separator 2, and the film 6 for adsorbing aluminum dust is arranged in the pipeline connected with the fan 1. The actual application scene of the improved milling surface dust removal system is shown in Figure 4-6 .

[0056] The multi-specification double-sided milling equipment negative pressure dust removal design and production method of the application comprises the following steps:

[0057] (1) Milling operation of the milling surface machine

[0058] Function: Milling the aluminum ingot by the cutter head of the device to produce thin aluminum strips.

[0059] Process parameters:

[0060] Aluminum ingot size: 6200mm x 495mm x 1060mm;

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

[0062] Milling product (thin aluminum strips) specifications: length about 1m, width about 10mm, thickness about 3mm.

[0063] (2) Crusher crushing treatment

[0064] Function: Crushing the thin aluminum strips produced by milling to generate short debris and aluminum dust.

[0065] Process parameters:

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

[0067] Product specifications after crushing: debris length about 20mm;

[0068] Byproduct (aluminum dust): particle diameter range 1-100μm.

[0069] (3) Air pipe conveying

[0070] Function: Sucking the aluminum debris and aluminum dust produced by the crusher into the cyclone separator to realize material transfer.

[0071] Process parameters:

[0072] Conveying medium: aluminum debris about 20mm long + aluminum dust 1-100μm in diameter;

[0073] Conveying path: from the crusher outlet to the cyclone separator inlet through the air pipe connection.

[0074] (4) Cyclone separator separation operation

[0075] Function: Separating large-particle aluminum debris by cyclone separation to achieve preliminary solid-gas separation.

[0076] Process parameters:

[0077] Separation object: large-particle aluminum debris (mainly debris about 20mm long);

[0078] Separation result: Large-particle aluminum debris is separated to the conveyor belt for collection, and the remaining gas carries the unseparated aluminum dust (1-100μm in diameter) into the next link.

[0079] (5) Fan suction and transportation

[0080] Function: Provide negative pressure power, suction and transportation of materials and gas.

[0081] Process parameters:

[0082] Suction object 1: fine aluminum strips (about 1m in length) generated by the milling equipment, transported to the crusher (previous equipment);

[0083] Suction object 2: gas and aluminum dust (1-100μm in diameter) separated by the cyclone separator, suctioned to the outdoor discharge link.

[0084] (6) Discharge filtration treatment

[0085] Function: Filtration of gas transported by the fan to achieve standard discharge.

[0086] Process parameters:

[0087] Treatment method: Membrane filtration for adsorbing aluminum dust arranged in the pipeline;

[0088] Discharge: Clean gas (remove aluminum dust with a diameter of 1-100μm) filtered by the membrane for adsorbing aluminum dust.

[0089] cyclone separator size unit box upper diameter a 155 cm box height b+c 200 cm lower outlet length f 282 cm lower outlet diameter e 90 cm box lower diameter 90 cm hopper height g 370 cm

[0090] Remarks:

[0091] 1. Material type: aluminum dust;

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

[0093] The power of the final fan is selected as 110KW, the fan air volume is 30000m 3 / h, and the fan pressure is 7200-7500pa, which can achieve the purpose of negative pressure dust removal.

[0094] The preparation method of the membrane for adsorbing aluminum dust comprises the following steps:

[0095] (1) Raw material pretreatment

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

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

[0098] (2) Mixing and dispersion

[0099] 1) 25-35 parts of polylactic acid are dissolved in 30-50 mL of ethyl acetate, and then emulsified with 50-80 mL of an aqueous phase solution containing polyvinyl alcohol and sodium dodecylbenzenesulfonate at a high speed of 2000-3000 r / min for 10-15 min to form a W / O emulsion, and the mass ratio of polyvinyl alcohol and sodium dodecylbenzenesulfonate is (2-5):(0.5-2);

[0100] 2) 20-35 parts of an aluminum-based adsorbent, 5-10 parts of nano-silicon dioxide, 3-8 parts of graphene oxide, and 1-3 parts of bamboo charcoal fiber are added to the W / O emulsion, and stirred at 500-1000 r / min for 30-60 min to obtain a mixed solution a;

[0101] (3) Crosslinking reaction

[0102] 1-3 parts of chitosan, 0.5-2 parts of glutaraldehyde, and 0.1-1 part of citric acid are added to the mixed solution a, the pH is adjusted to 4-6, and then reacted at 40-60°C for 2-4 h to obtain a mixed solution b;

[0103] (4) Film forming treatment

[0104] The mixed solution b is poured into a flat plate mold, the thickness is controlled to be 50-100 microns, and dried at 50-70°C for 12-24 h to form a wet film;

[0105] (5) Surface modification

[0106] The wet film is soaked in an ethanol solution of nano-zinc oxide with a mass concentration of 0.1-1%, and ultrasonic treated at an ultrasonic power of 300-500 W and a frequency of 20-40 kHz for 10-15 min to form an antibacterial coating, and then taken out and dried at room temperature for 2-4 h to obtain a dried film;

[0107] (6) Temperature rising treatment

[0108] The dried film is subjected to temperature rising treatment, and the temperature is raised to 100-120°C at a rate of 2-5°C / min, and kept for 1.5-2 h to enhance the mechanical strength, and then naturally cooled to room temperature to obtain a finished film for adsorbing aluminum dust.

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

[0110] (1) Sol preparation

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

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

[0113] (2) Gel forming

[0114] Chitosan addition: 2-4 parts of chitosan are dissolved in 40-50 mL of 1-1.3% acetic acid solution, then auxiliary dissolution is carried out at 48-52℃ for 1-1.2 h to obtain a uniform gel;

[0115] Foaming treatment: 6-10 parts of ammonium bicarbonate and 0.1-0.3 parts of Tween-80 are added to the uniform gel, and the reaction is carried out at a temperature of 30-35℃ and a stirring speed of 300-500 r / min for 30-60 min to generate bubbles and form a porous precursor;

[0116] (3) Hydrothermal crystallization

[0117] Crystallization conditions: the porous precursor is transferred to a polytetrafluoroethylene-lined autoclave, and crystallization is carried out at 120-150℃ for 12-24 h to promote the growth of Al 3+ coordination network with citric acid;

[0118] Cooling treatment: naturally cooled to room temperature, centrifuged, washed with deionized water and ethanol alternately for 3-5 times to remove unreacted impurities, and the product is obtained;

[0119] (4) Calcination activation

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

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

[0122] The preparation technology principle of the film for adsorbing aluminum dust of the present application:

[0123] I. 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 4-6h can effectively remove the moisture contained in the raw materials. The presence of moisture will interfere with the interaction between the raw materials in the subsequent mixing and dispersion process, such as affecting the stability of the emulsion, and may also form bubbles and other defects after film formation, reducing the performance of the film. Through drying treatment, these raw materials can fully play a role in the subsequent steps.

[0126] Activating aluminum-based adsorbent at 100-120℃ for 2-3h can break the inert layer on its surface, increase the number of active sites on the surface, and improve the adsorption affinity for aluminum dust, thereby enhancing its adsorption activity.

[0127] 2. Mixing and dispersion

[0128] Dissolve polylactic acid in ethyl acetate at a specific ratio, then emulsify it with an aqueous solution containing polyvinyl alcohol and sodium dodecylbenzenesulfonate to form a W / O emulsion. The mass ratio of polyvinyl alcohol and sodium dodecylbenzenesulfonate is (2-5):(0.5-2), which can play a synergistic emulsification role, reduce the oil-water interfacial tension, and make the water phase uniformly dispersed in the oil phase in the form of small droplets, forming a stable emulsion system that provides a good carrier for the uniform dispersion of other raw materials. High-speed emulsification at 2000-3000r / min and a time of 10-15min can ensure the stability and uniformity of the emulsion.

[0129] Add aluminum-based adsorbent, nano-silicon dioxide, graphene oxide, and bamboo charcoal fiber to the W / O emulsion, stir at 500-1000r / min for 30-60min, which can ensure that these solid raw materials are fully dispersed in the emulsion and avoid agglomeration. This can ensure that they are uniformly distributed in the film, laying the foundation for the excellent performance of the subsequent film.

[0130] 3. Crosslinking reaction

[0131] Add 1-3 parts of chitosan, 0.5-2 parts of glutaraldehyde, and 0.1-1 parts of citric acid to the mixed solution a, adjust the pH to 4-6, and react at 40-60℃ for 2-4h. The amino groups in the chitosan molecule can crosslink with the aldehyde groups of glutaraldehyde, and citric acid can also participate in crosslinking, forming a three-dimensional network structure. This can enhance the mechanical strength and chemical stability of the film, preventing the film from dissolving or breaking during use. Specific pH and temperature conditions can ensure the smooth progress of the crosslinking reaction and the moderate degree of reaction.

[0132] 4. Film forming treatment

[0133] The mixed solution b is poured into a flat mold to control the thickness of 50-100 microns, dried at 50-70℃ for 12-24h to form a wet film. Controlling the thickness can ensure the uniformity of the film and the adsorption efficiency during use, and too thick will result in slow adsorption rate, and too thin may not have enough strength. Drying at this temperature and time can slowly remove the solvent, avoiding defects such as cracking and wrinkling of the film due to too fast drying.

[0134] 5. Surface modification

[0135] The wet film is soaked in an ethanol solution of nano-zinc oxide with a mass concentration of 0.1-1% for 10-15min under specific ultrasonic conditions. Nano-zinc oxide can form an antibacterial coating on the surface of the film, giving the film antibacterial properties and preventing the film from being clogged by bacteria during use, affecting the adsorption effect. Ultrasonic treatment can make nano-zinc oxide uniformly adhere to the surface of the film, enhancing the adhesion between the coating and the film. Drying at room temperature for 2-4h can volatilize the ethanol and fix the antibacterial coating.

[0136] 6. Temperature rising treatment

[0137] The dried film is heated to 100-120℃ at a rate of 2-5℃ / min and kept at this temperature for 1.5-2h. Slow heating can avoid internal stress in the film due to sudden temperature rise, leading to cracking. Keeping the temperature at this level can further promote the interaction between the molecules in the film, such as enhancing the stability of the cross-linked structure, thereby significantly enhancing the mechanical strength of the film. After natural cooling, the performance of the film is more stable.

[0138] II. Synergistic effect between raw materials

[0139] 1. Polylactic acid as the matrix material of the film has good film-forming property and biocompatibility, providing a support framework for other raw materials, so that aluminum-based adsorbent, graphene oxide, bamboo charcoal fiber, etc. can be uniformly distributed in the film.

[0140] 2. Graphene oxide has abundant oxygen-containing functional groups and large specific surface area, and bamboo charcoal fiber also has porous structure, which synergizes with aluminum-based adsorbent. Aluminum-based adsorbent provides the main adsorption active sites, and the porous structure of graphene oxide and bamboo charcoal fiber can serve as adsorption channels to increase the contact opportunities between aluminum dust and adsorption sites, thereby improving the adsorption capacity and adsorption rate of the film for aluminum dust.

[0141] 3. Nano-silicon dioxide can be filled in the pores of the film, combined with the polylactic acid matrix to enhance the mechanical strength and wear resistance of the film, and the hydroxyl groups on its surface can interact with other raw materials to further stabilize the structure of the film.

[0142] 4. The reticular structure formed by cross-linking reaction of chitosan, glutaraldehyde and citric acid tightly binds all the raw materials together, not only enhances the overall stability of the membrane, but also prevents the raw materials from falling off during use, prolonging 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 surface of the membrane, avoid bacterial blockage of the pores of the membrane, and ensure the unobstructed passage of aluminum dust adsorption channels, thus maintaining the long-term high adsorption performance of the membrane in cooperation with other raw materials with adsorption function.

[0144] The synergistic effect between these raw materials significantly improves the adsorption capacity, mechanical strength, antibacterial property and service life of the prepared membrane, achieving unexpected technical effects better than the 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 time is too short, the water in the raw materials cannot be completely removed, which will affect the subsequent mixing, dispersion and cross-linking reaction. If the temperature is too high, it may cause degradation of polylactic acid and other raw materials. If the activation temperature and time of aluminum-based adsorbent are not appropriate, the number of active sites will be insufficient, reducing the adsorption performance. Optimizing these parameters can ensure that the raw materials are in the best state.

[0147] 2. Mixing and dispersion parameters: If the emulsification speed and time are not enough, a stable W / O emulsion cannot be formed, and the raw materials cannot be uniformly dispersed, which will cause differences in the performance of the membrane. If the speed is too high, the emulsion system may be destroyed. If the stirring speed and time are not appropriate, the solid raw materials will agglomerate and cannot be uniformly dispersed in the emulsion, affecting the overall performance of the membrane. Optimizing these parameters can ensure uniform dispersion of the raw materials and lay a foundation for excellent performance of the membrane.

[0148] 3. Cross-linking reaction parameters: If the pH value is not appropriate, it will affect the degree of cross-linking reaction. If the reaction temperature and time are insufficient, the cross-linking will not be sufficient, and the strength and stability of the membrane will be poor. If the reaction is excessive, the porosity of the membrane may be reduced, affecting the adsorption performance. Optimizing these parameters can make the cross-linking reaction reach an ideal state.

[0149] 4. Film forming treatment parameters: If the thickness of the membrane is not appropriate, it will affect its adsorption efficiency and mechanical strength. If the drying temperature and time are not appropriate, it will cause defects in the membrane. Optimizing these parameters can ensure the stability of the form and performance of the membrane.

[0150] 5. Surface modification parameters: If the concentration of nano-zinc oxide solution is too high, it will cause the pores of the membrane to be blocked. If the concentration is too low, the antibacterial effect will be poor. If the ultrasonic power, frequency and treatment time are not appropriate, it will affect the adhesion of nano-zinc oxide on the surface of the membrane. Optimizing these parameters can make the antibacterial coating play the best role.

[0151] 6. Temperature treatment parameters: too fast heating rate will cause internal stress of the membrane, leading to cracking; inappropriate holding temperature and time cannot achieve the effect of enhancing mechanical strength. Optimization of these parameters can ensure that the mechanical strength of the membrane is effectively improved.

[0152] In summary, various process parameters interact and restrict each other. Only by optimizing them can each preparation step be in the best state, so as to prepare a membrane for adsorbing aluminum dust with excellent performance, stability and reliability, and achieve unexpected good technical effects. If the process parameters are not appropriate, the performance of the membrane may be reduced, and even the use requirements cannot be met.

[0153] Technical principle of preparation of the aluminum-based adsorbent of the application:

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

[0155] I. Specific role of each preparation step

[0156] 1. Sol preparation

[0157] Raw material mixing: 30-40 parts of aluminum nitrate trihydrate, 12-18 parts of citric acid, and 10-15 parts of polyethylene glycol are dissolved in 30-40 mL of deionized water and 15-20 mL of ethanol to form a transparent sol under a specific stirring speed and temperature. In this process, aluminum nitrate trihydrate serves as an aluminum source and dissociates Al 3+ in the solvent; citric acid reacts with Al 3+ to form a stable aluminum-citric acid complex; polyethylene glycol is dissolved in the mixed solvent, and the steric hindrance of its molecular chain uniformly disperses the aluminum-citric acid complex, avoiding agglomeration and laying a foundation for the subsequent formation of a uniform sol system. At the same time, appropriate stirring speed (500-800 r / min) and temperature (40-60℃) can promote the dissolution and reaction of the raw materials, and a reaction time of 2-3 h ensures the complete complexation reaction, thereby forming a stable transparent sol.

[0158] pH adjustment: adjust the pH of the sol to 4.5-5.5 with ammonia water. This operation is to adjust the acidity and alkalinity of the sol so that the aluminum-citric acid complex remains stable in this pH range. If the pH is too low, the complex will dissociate; if the pH is too high, Al 3+ may hydrolyze to form aluminum hydroxide precipitate, destroying the stability of the sol system. The adjusted pH environment creates suitable conditions for the 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 was heated to 300-320°C at 3-5°C / min under nitrogen atmosphere and kept for 2-2.5h. The nitrogen atmosphere can prevent the product from being oxidized at high temperature. Slow heating (3-5°C / min) can avoid the product structure from being destroyed due to sharp temperature change. The temperature of 300-320°C and the holding time of 2-2.5h can make polyethylene glycol and ammonium bicarbonate fully decompose and be removed, and meanwhile form mesoporous and macroporous structures in the product, which can significantly increase the specific surface area of the adsorbent and provide more active sites for the adsorption process.

[0167] Surface modification: The cooled product was immersed in an ethanol solution of 3-aminopropyltriethoxysilane with a mass concentration of 0.3-0.5% for 1.5-2h, and then dried at 47-52°C. The amino group in 3-aminopropyltriethoxysilane can react with the hydroxyl group on the surface of the product, thereby introducing the amino group onto the surface of the adsorbent. The amino group has strong adsorption capacity and can interact with many adsorbates, thereby significantly improving the adsorption performance of the adsorbent. The drying temperature of 47-52°C can remove the ethanol solvent while ensuring the stable combination of the amino group on the surface of the adsorbent.

[0168] II. Synergistic effect between raw materials and performance improvement

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

[0170] 2. Synergistic effect between chitosan and foaming agent, surfactant: The gel formed by chitosan provides a skeleton structure for the whole system. The bubbles generated by the decomposition of ammonium bicarbonate can be uniformly distributed in the chitosan gel skeleton under the stabilizing action of Tween-80, forming a large number of porous structures. The skeleton effect of chitosan ensures the stability of the porous structure, and the porous structure greatly increases the specific surface area of the adsorbent. The synergistic effect of the three makes the adsorbent have abundant pores, providing more channels and space for the adsorbate and significantly improving the adsorption capacity.

[0171] 3. Synergy 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. Meanwhile, the abundant pore structure cooperates with the surface amino groups, not only capturing substances through physical adsorption in the pores, but also enhancing the adsorption capacity for target substances through chemical adsorption of amino groups. The combined action of the two makes the adsorption performance of the aluminum-based adsorbent unexpectedly improved.

[0172] III. 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 r / min can ensure that the raw materials are fully mixed and reacted, avoiding uneven reaction caused by excessive local concentration. If the stirring speed is too low, the raw materials will not be fully mixed, affecting the stability of the sol; if it is too high, the solvent may be excessively volatilized, which is also not conducive to the sol system. The optimized stirring speed ensures the uniformity of the sol, providing a good foundation for subsequent processes.

[0174] 2. Temperature: The temperature parameters for different steps are optimized. A temperature of 40-60°C during raw material mixing promotes the dissolution of raw materials and the progress of complexation reaction; a temperature of 48-52°C during chitosan dissolution ensures its complete dissolution; a temperature of 30-35°C during foaming treatment allows ammonium bicarbonate to decompose at an appropriate rate, facilitating the formation and stabilization of bubbles; a temperature of 120-150°C during hydrothermal crystallization promotes the growth of crystal structures; the temperatures for calcination and drying are also precisely controlled to ensure the effects of template removal and surface modification. Suitable temperature parameters can ensure that each reaction step proceeds as expected. If the temperature is not appropriate, it may lead to incomplete reaction, structural damage, etc. Optimized temperature parameters make the structure and performance of the product more excellent, such as more complete crystal structure and more abundant porous structure.

[0175] 3. Time: The reaction time of each step is also a key to optimization. Raw material mixing reaction for 2-3 h ensures the completion of complexation reaction; chitosan stirring for 1-1.2 h ensures complete dissolution; foaming reaction for 30-60 min allows bubbles to form fully; crystallization for 12-24 h promotes crystal growth; calcination for 2-2.5 h ensures complete removal of templates; surface modification soaking for 1.5-2 h ensures sufficient loading of amino groups. Sufficient reaction time can ensure complete reaction, but if the time is too long, it will reduce production efficiency and increase costs. Optimized time parameters ensure complete reaction while improving production efficiency and reducing costs.

[0176] 4. pH value: Adjusting the pH of the sol to 4.5-5.5 is key to ensuring sol stability. Suitable pH value avoids Al 3+The hydrolysis and dissociation of the complex ensure the smooth progress of the subsequent gel formation. If the pH value is not in the range, the sol system may be destroyed and the ideal gel structure cannot be formed. The optimized pH value parameter ensures the stability of the entire preparation process, and finally makes the product performance stable.

[0177] Through the optimization of various process parameters, the aluminum-based adsorbent prepared has more excellent performance, such as significantly increased specific surface area, increased adsorption capacity, accelerated adsorption rate, and enhanced selectivity to target substances. These unexpected technical effects make the aluminum-based adsorbent have a broader application prospect in the field of gas adsorption, and the optimized process parameters also improve the stability and efficiency of production, reduce production cost, and have important practical application value.

[0178] In order to make the present disclosure more complete, the following will be described by more specific examples.

[0179] I. Examples

[0180] Example 1

[0181] A multi-specification double-sided milling equipment negative pressure dust removal design and manufacturing method, comprising the following steps:

[0182] (1) Milling operation of the milling machine

[0183] Function: Through the cutter head of the equipment, the aluminum plate ingot is subjected to large face milling to produce fine aluminum strips.

[0184] (2) Breaking treatment of the crusher

[0185] Function: The fine aluminum strips generated by milling are broken to generate short debris and aluminum dust.

[0186] (3) Air pipe conveying

[0187] Function: The aluminum chips and aluminum dust generated by the crusher are sucked into the cyclone separator to realize material transfer.

[0188] Conveying path: From the outlet of the crusher to the inlet of the cyclone separator through the air pipe.

[0189] (4) Separation operation of the cyclone separator

[0190] Function: Large particle aluminum chips are separated by cyclone separation to realize preliminary solid-gas separation.

[0191] Process parameters:

[0192] Separation object: large particle aluminum chips;

[0193] Separation result: The large particle aluminum chips are separated to the conveyor belt for collection, and the remaining gas carrying unseparated aluminum dust (1-100 μm in diameter) enters the next link.

[0194] (5) Fan suction and transportation

[0195] Function: Provide negative pressure power, suction and transportation of materials and gas.

[0196] Process parameters:

[0197] Suction object 1: fine aluminum strips generated by the milling equipment, transported to the crusher (previous equipment);

[0198] Suction object 2: gas and aluminum dust (1-100 μm in diameter) separated by the cyclone separator, suctioned to the outdoor discharge link.

[0199] (6) Discharge filtration treatment

[0200] Function: Filter the gas transported by the fan to achieve standard discharge.

[0201] Process parameters:

[0202] Treatment method: Membrane filtration for adsorbing aluminum dust is set in the pipeline;

[0203] Discharge: Clean gas (remove aluminum dust 1-100 μm in diameter) filtered by the membrane for adsorbing aluminum dust.

[0204] The preparation method of 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°C for 5h to remove water;

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

[0208] (2) Mixing and dispersion

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

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

[0211] (3) Crosslinking reaction

[0212] Mixing solution b was prepared by adding 2 parts of chitosan, 1 part of glutaraldehyde and 0.5 part of citric acid into mixing solution a, adjusting pH to 5, and then reacting at 50°C for 3h;

[0213] (4) Film forming treatment

[0214] Mixing solution b was poured into a flat plate mold, and the thickness was controlled to be 75 microns, and then dried at 60°C for 18h to form a wet film;

[0215] (5) Surface modification

[0216] The wet film was immersed in an ethanol solution of nano-zinc oxide with a concentration of 0.5%, and ultrasonic treatment was performed at an ultrasonic power of 400W and a frequency of 30kHz for 12min to form an antibacterial coating, and then taken out and dried at room temperature for 3h to obtain a dried film;

[0217] (6) Temperature rising treatment

[0218] The dried film was subjected to temperature rising treatment, and the temperature was raised to 110°C at a rate of 3°C / min, and then kept for 1.7h to enhance the mechanical strength, and then naturally cooled to room temperature to obtain a film product for adsorbing aluminum dust.

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

[0220] (1) Sol preparation

[0221] Raw material mixing: 35 parts of aluminum nitrate trihydrate, 15 parts of citric acid and 12 parts of polyethylene glycol were dissolved in 35mL of deionized water and 17mL of ethanol, and the transparent sol was formed by reacting at a stirring speed of 650r / min and a temperature of 50°C for 2.5h;

[0222] pH adjustment: the pH of the sol was adjusted to 5.0 by using ammonia water to obtain the pH-adjusted sol;

[0223] (2) Gel forming

[0224] Chitosan addition: 3 parts of chitosan were dissolved in 45mL of 1.15% acetic acid solution, and then auxiliary dissolution was performed by stirring at 50°C for 1.1h to obtain a uniform gel;

[0225] Foaming treatment: 8 parts of ammonium bicarbonate and 0.2 parts of Tween-80 were added to the uniform gel, and the reaction was carried out at a temperature of 32°C and a stirring speed of 400r / min for 45min to generate bubbles to form a porous precursor;

[0226] (3) Hydrothermal crystallization

[0227] Crystallization conditions: the porous precursor was transferred to a high-pressure kettle with a polytetrafluoroethylene liner, and crystallization was carried out at 135°C for 18h to promote Al 3+Complexation network growth with citric acid;

[0228] Cooling treatment: natural cooling to room temperature, centrifugal separation, washing with deionized water and ethanol alternately 4 times to remove unreacted impurities, and obtaining the product;

[0229] (4) Calcination activation

[0230] Template removal: the product was heated to 310 DEG C at 4 DEG C / min under nitrogen atmosphere, and maintained for 2.2 h to decompose polyethylene glycol and ammonium bicarbonate, forming a product with mesoporous and macroporous structures;

[0231] Surface modification: the product with mesoporous and macroporous structures after cooling was immersed in an ethanol solution of 3-aminopropyltriethoxysilane with a mass concentration of 0.4% for 1.7 h, and then dried at 50 DEG C to re-introduce amino groups, thereby preparing an aluminum-based adsorbent.

[0232] Example 2

[0233] A design and manufacturing method of a multi-specification double-sided milling equipment negative pressure dust removal, the preparation process is basically the same as example 1, the only difference is the preparation method of the film used for adsorbing aluminum dust, including the following steps:

[0234] (1) Raw material pretreatment

[0235] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60 DEG C for 6 h to remove water;

[0236] 2) Activate the aluminum-based adsorbent at 100 DEG C for 3 h to enhance the adsorption activity;

[0237] (2) Mixing and dispersing

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

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

[0240] (3) Crosslinking reaction

[0241] Add 1 part of chitosan, 0.5 part of glutaraldehyde and 0.1 part of citric acid to the mixed solution a, adjust the pH to 4, and then react at 40 DEG C for 4 h to obtain a mixed solution b;

[0242] (4) Film forming treatment

[0243] The mixed solution b is poured into a flat mold, and the thickness is controlled to be 50 microns, and dried at 50°C for 24h to form a wet film;

[0244] (5) Surface modification

[0245] The wet film is soaked in an ethanol solution of 0.1% nano zinc oxide, and ultrasonic treatment is carried out at an ultrasonic power of 300W and a frequency of 20kHz for 15min to form an antibacterial coating, and then taken out and dried at room temperature for 4h to obtain a dried film;

[0246] (6) Temperature rising treatment

[0247] The dried film is subjected to temperature rising treatment, and the temperature is raised to 100°C at a rate of 2°C / min, and the temperature is kept for 2h to enhance the mechanical strength, and then naturally cooled to room temperature to obtain a finished film for adsorbing aluminum dust.

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

[0249] (1) Sol preparation

[0250] Raw material mixing: 30 parts of aluminum nitrate trihydrate, 12 parts of citric acid, and 10 parts of polyethylene glycol are dissolved in 30mL of deionized water and 15mL of ethanol, and the reaction is carried out at a stirring speed of 500r / min and a temperature of 40°C for 3h to form a transparent sol;

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

[0252] (2) Gel forming

[0253] Chitosan addition: 2 parts of chitosan are dissolved in 40mL of 1% acetic acid solution, and then auxiliary dissolution is carried out at 48°C for 1.2h to obtain a uniform gel;

[0254] Foaming treatment: 6 parts of ammonium bicarbonate and 0.1 parts of Tween-80 are added to the uniform gel, and the reaction is carried out at a temperature of 30°C and a stirring speed of 300r / min for 60min to produce bubbles to form a porous precursor;

[0255] (3) Hydrothermal crystallization

[0256] Crystallization conditions: the porous precursor is transferred to a polytetrafluoroethylene-lined autoclave, and crystallization is carried out at 120°C for 24h to promote the growth of Al 3+ coordination network with citric acid;

[0257] Cooling treatment: naturally cooled to room temperature, centrifuged, washed with deionized water and ethanol alternately for 3 times, and unreacted impurities are removed to obtain the product;

[0258] (4) Calcination activation

[0259] Template removal: the product was heated to 300°C at a rate of 3°C / min under a nitrogen atmosphere, and maintained for 2.5 h to decompose the polyethylene glycol and ammonium bicarbonate, forming a mesoporous and macroporous structured product;

[0260] Surface modification: the cooled mesoporous and macroporous structured product was immersed in an ethanol solution of 3-aminopropyltriethoxysilane with a mass concentration of 0.3% for 2 h, and then dried at 47°C to reintroduce the amino group, thereby preparing an aluminum-based adsorbent.

[0261] Example 3

[0262] A design and fabrication method for a multi-specification double-sided milling equipment negative pressure dust removal, the preparation process is basically the same as that of example 1, the only difference is the preparation method of the film for adsorbing aluminum dust, which comprises the following steps:

[0263] (1) Raw material pretreatment

[0264] 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 80°C for 4h to remove water;

[0265] 2) Activate the aluminum-based adsorbent at 120°C for 2h to enhance the adsorption activity;

[0266] (2) Mixing and dispersing

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

[0268] 2) Add 30 parts of aluminum-based adsorbent, 10 parts of nano-silicon dioxide, 8 parts of graphene oxide, and 3 parts of bamboo charcoal fiber to the W / O emulsion, and stir at 1000 r / min for 30 min to prepare a mixed solution a;

[0269] (3) Crosslinking reaction

[0270] Add 3 parts of chitosan, 2 parts of glutaraldehyde and 1 part of citric acid to the mixed solution a, adjust the pH to 6, and then react at 60°C for 2h to prepare a mixed solution b;

[0271] (4) Film forming treatment

[0272] Pour the mixed solution b into a flat plate mold, control the thickness to be 100 microns, and dry at 70°C for 12h to form a wet film;

[0273] (5) Surface modification

[0274] The wet film is soaked in an ethanol solution of nano-zinc oxide with a concentration of 1%, and is subjected to ultrasonic treatment for 10 min under an ultrasonic power of 500 W and a frequency of 40 kHz to form an antibacterial coating, and then is taken out and dried at room temperature for 2 h to obtain a dried film;

[0275] (6) Temperature rising treatment

[0276] The dried film is subjected to temperature rising treatment at a temperature rising rate of 5 ℃ / min to 120 ℃, and is kept at 120 ℃ for 1.5 h to enhance the mechanical strength, and is naturally cooled to room temperature to obtain a finished film for adsorbing aluminum dust.

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

[0278] (1) Sol preparation

[0279] Raw material mixing: 40 parts of aluminum nitrate trihydrate, 18 parts of citric acid and 15 parts of polyethylene glycol are dissolved in 40 mL of deionized water and 20 mL of ethanol, and the mixture is reacted at a stirring speed of 800 r / min and a temperature of 60 ℃ for 2 h to form a transparent sol;

[0280] pH adjustment: the pH of the sol is adjusted to 5.5 by using ammonia water to obtain a pH-adjusted sol;

[0281] (2) Gel forming

[0282] Chitosan addition: 4 parts of chitosan are dissolved in 50 mL of an acetic acid solution with a mass concentration of 1.3%, and then the mixture is stirred at 52 ℃ for 1 h to assist the dissolution, and a uniform gel is obtained;

[0283] Foaming treatment: 10 parts of ammonium bicarbonate and 0.3 parts of Tween-80 are added to the uniform gel, and the mixture is reacted at a temperature of 35 ℃ and a stirring speed of 500 r / min for 30 min to generate bubbles to form a porous precursor;

[0284] (3) Hydrothermal crystallization

[0285] Crystallization conditions: the porous precursor is transferred to a polytetrafluoroethylene-lined autoclave, and is crystallized at 150 ℃ for 12 h to promote the growth of the coordination network of Al 3+ and citric acid;

[0286] Cooling treatment: naturally cooled to room temperature, centrifuged and washed with deionized water and ethanol alternately for 5 times to remove unreacted impurities, and a product is obtained;

[0287] (4) Calcination activation

[0288] Template removal: the product is heated to 320 ℃ at a temperature rising rate of 5 ℃ / min under a nitrogen atmosphere, and is kept at 320 ℃ for 2 h to decompose the polyethylene glycol and ammonium bicarbonate, and a product with mesoporous and macroporous structures is formed;

[0289] Surface modification: the cooled product forming mesoporous and macroporous structure was immersed in a 3-aminopropyltriethoxysilane ethanol solution with a mass concentration of 0.5% for 1.5 h, and then dried at 52°C to re-introduce amino groups, thereby preparing an aluminum-based adsorbent.

[0290] Example 4

[0291] A multi-specification double-sided milling equipment negative pressure dust removal design and manufacturing method, the preparation process is basically the same as that of example 1, except that the preparation method of the film for adsorbing aluminum dust includes the following steps:

[0292] (1) Raw material pretreatment

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

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

[0295] (2) Mixing and dispersing

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

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

[0298] (3) Crosslinking reaction

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

[0300] (4) Film forming treatment

[0301] Pour the mixed solution b into a flat plate mold, control the thickness to be 60 microns, and dry at 55°C for 20 h to form a wet film;

[0302] (5) Surface modification

[0303] Soak the wet film in an ethanol solution of nano zinc oxide with a concentration of 0.3%, and ultrasonic treat at an ultrasonic power of 350 W and a frequency of 25 kHz for 14 min to form an antibacterial coating, then take it out and dry at room temperature for 3.5 h to obtain a dried film;

[0304] (6) Temperature rising treatment

[0305] The dried film is subjected to temperature rising treatment, rising to 105°C at 3°C / min, and kept for 1.8h to enhance the mechanical strength, and naturally cooled to room temperature, to obtain the film product for adsorbing aluminum dust.

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

[0307] Example 5

[0308] A multi-specification double-sided milling equipment negative pressure dust removal design and manufacturing method, the preparation process is basically the same as Example 1, except that the preparation method of the film for adsorbing aluminum dust includes the following steps:

[0309] (1) Raw material pretreatment

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

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

[0312] (2) Mixing and dispersing

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

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

[0315] (3) Crosslinking reaction

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

[0317] (4) Film forming treatment

[0318] Pour the mixed solution b into a flat plate mold, control the thickness to be 90 microns, dry at 65°C for 15h to form a wet film;

[0319] (5) Surface modification

[0320] The wet film was immersed in an ethanol solution of nano-zinc oxide with a concentration of 0.8%, and was ultrasonically treated for 11 min under an ultrasonic power of 450 W and a frequency of 35 kHz to form an antibacterial coating, and then was taken out and dried at room temperature for 2.5 h to obtain a dried film;

[0321] (6) Temperature treatment

[0322] The dried film was subjected to temperature treatment, and was heated to 115°C at a rate of 4°C / min and was kept at 115°C for 1.6 h to enhance the mechanical strength, and was naturally cooled to room temperature to obtain a finished film for adsorbing aluminum dust.

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

[0324] II. Comparative Examples

[0325] Comparative Example 1

[0326] The process is basically the same as that in Example 1, except that the amount of the aluminum-based adsorbent 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, and the other steps and parameters are the same as those 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 cross-linking reaction is adjusted to 3, and the other steps and parameters are the same as those 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 the film-forming treatment is 40°C, and the other steps and parameters are the same as those 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 during the surface modification is 2%, and the other steps and parameters are the same as those in Example 1.

[0335] Comparative Example 6

[0336] The process is basically the same as that in Example 1, except that the heating rate during the temperature treatment is 1°C / min, and the other steps and parameters are the same as those in Example 1.

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

[0338] process parameters horizontal adsorption efficiency (%) tensile strength (MPa) aluminum-based adsorbent dosage (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 cross-linking reaction pH value 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 (℃) 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 surface-modified nano-zinc oxide concentration (%) 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 temperature rising treatment temperature (℃) 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] The conclusions obtained from the above table are analyzed as follows:

[0340] (1) The dosage of aluminum-based adsorbent: When the dosage is less than 25 parts, the adsorption active site is insufficient, resulting in low adsorption efficiency; when the dosage is greater than 25 parts, too much aluminum-based adsorbent will affect the structural integrity of the membrane, causing the tensile strength to decrease slightly, and the adsorption effect may be affected due to particle agglomeration, resulting in a decrease in adsorption efficiency. The relatively optimal dosage is 20-35 parts, and the optimal dosage is 25 parts.

[0341] (2) The dosage of polylactic acid: When the dosage is too small, the film-forming property of the membrane is poor, the structure is not stable, and the adsorption efficiency and mechanical strength are affected; when the dosage is too large, the porosity of the membrane may decrease, hindering the adsorption of aluminum dust, resulting in a decrease in adsorption efficiency. The relatively optimal dosage is 25-35 parts, and the optimal dosage is 30 parts.

[0342] (3) The 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 low; when the pH value is too high, part of the ingredients may be hydrolyzed or precipitated, affecting the performance of the membrane. The relatively optimal pH value is 4-6, and the optimal pH value is 5.

[0343] (4) The drying temperature for film formation: When the temperature is too low, the drying speed is slow, and there may be too much water remaining in the membrane, affecting the structure and performance of the membrane; when the temperature is too high, the drying speed is too fast, which may cause the membrane surface to crack or the internal structure to be uneven, reducing the adsorption efficiency and mechanical strength. The relatively optimal temperature is 50-70°C, and the optimal temperature is 60°C.

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

[0345] (6) The temperature of temperature rising treatment: When the temperature is too low, the mechanical strength of the membrane cannot be fully enhanced; when the temperature is too high, part of the ingredients of the membrane may be decomposed or the structure may be damaged, causing the adsorption efficiency and mechanical strength to decrease. The relatively optimal temperature is 100-120°C, and the optimal temperature is 110°C.

[0346] Four, performance index detection test

[0347] Test index and method

[0348] (1) Adsorption efficiency: in the simulated aluminum dust environment, under the conditions of wind speed 2 m / s and dust concentration 50 mg / m 3The adsorption efficiency, static adsorption saturation time and adsorption efficiency retention rate after 5 times of ethanol elution were tested according to the corresponding methods.

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

[0350] (3) Environmental protection: the biodegradability of raw materials was detected, whether it conforms to the EU REACH standard, and whether there is heavy metal release.

[0351] (4) Antibacterial performance: the antibacterial rate on E. coli was tested according to the GB / T20944.3-2008.

[0352] item 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 times of ethanol elution (%) 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 comply comply comply comply comply comply comply comply comply comply comply bacteriostatic 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] The conclusion obtained from the above table is analyzed as follows:

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

[0355] (2) Static adsorption saturation time: the saturation time of the examples is shorter, which indicates that the adsorption rate of the membrane of the examples is faster, and the adsorption saturation can be reached more quickly, thereby improving the 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 times of ethanol elution: the retention rate of the examples is higher, which indicates that the membrane of the examples has better regeneration performance, and can be used more times, thereby reducing the use cost. This is related to the stable structure of the membrane and the good combination of the adsorbent and the membrane.

[0357] (4) Tensile strength: the tensile strength of the examples is all ≥8.1 MPa, which meets the requirements and is higher than that of the comparative examples, indicating that the mechanical performance of the membrane of the examples is more excellent, and the flexibility is good, and the membrane can be repeatedly folded and used. This is because the appropriate temperature treatment and other processes enhance the mechanical strength of the membrane.

[0358] (5) Antibacterial performance: the antibacterial rate of the examples on E. coli is higher, indicating that the antibacterial performance of the examples is more excellent, and the bacteria can be effectively prevented from breeding, thereby prolonging 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 the key process parameters, the membrane for adsorbing aluminum dust prepared in the examples is superior to the comparative examples in terms of adsorption efficiency, mechanical strength, regeneration performance, antibacterial performance and the like, has significant progress, and proves the creativity and superiority of the technology of the application.

[0360] The above description is further detailed in connection with specific / preferred embodiments of the present application, and should not be construed as limiting the specific implementation of the present application to these descriptions. For those skilled in the art to which the present application pertains, several substitutions or modifications can be made to the described embodiments without departing from the concept of the present application, and these substitutions or modifications should be considered as falling within the scope of protection of the present application.

Claims

1. A multi-specification double-sided milling equipment negative pressure dust removal design and manufacturing method, characterized in that, Comprise the following steps: (1) milling machine milling operation Through the device cutter head to aluminum plate ingot big face milling, produce fine aluminum strip; (2) crushing machine crushing treatment The fine aluminum strip produced by milling is crushed to generate short chips and aluminum dust; (3) air pipe conveying The aluminum chips and aluminum dust generated by the crusher are sucked into the cyclone separator to realize the transfer of the material; (4) cyclone separator separation operation Separate large particle aluminum chips by cyclone separation to achieve preliminary separation of solid and gas; (5) fan suction and conveying Provide negative pressure power to suck and convey the material and gas; (6) discharge filtration treatment Filter the gas conveyed by the fan with a membrane for adsorbing aluminum dust to achieve standard discharge.

2. The method of claim 1, wherein the method further comprises: The size of the aluminum plate ingot in step (1) is: 6200mm x 495mm x 1060mm.

3. The method of claim 1, wherein the method further comprises: The cutting parameters in step (1) are: linear speed 500-3000mm / min, feed rate: 10mm.

4. The method of claim 1, wherein the method further comprises: The diameter of the aluminum dust in step (2) is 1-100μm.

5. The method of claim 1, wherein the method further comprises: The cyclone separator in step (3) is provided with a gas locking and ash discharging device below.

6. The method of claim 1, wherein the method further comprises: The conveying path in step (3) is connected from the crusher outlet to the cyclone separator inlet through the air pipe.

7. The method of claim 1, wherein the method further comprises: The power of the fan in step (5) is selected as 110KW, the air volume of the fan is 30000m 3 / h, and the air pressure is 7200-7500pa.

8. The method of claim 1, wherein the method further comprises: The preparation method of the membrane for adsorbing aluminum dust in step (6) comprises the following steps: (1) raw material pretreatment 1) Dry polylactic acid, graphene oxide and bamboo charcoal fiber at 60-80℃ for 4-6h to remove water; 2) Activate the aluminum-based adsorbent at 100-120℃ for 2-3h to enhance the adsorption activity; (2) mixing and dispersing 1) Dissolve 25-35 parts of polylactic acid in 30-50mL of ethyl acetate, then emulsify with 50-80mL of aqueous solution containing polyvinyl alcohol and sodium dodecylbenzenesulfonate at 2000-3000r / min for 10-15min to form a W / O emulsion; 2) Add 20-35 parts of aluminum-based adsorbent, 5-10 parts of nano silicon dioxide, 3-8 parts of graphene oxide and 1-3 parts of bamboo charcoal fiber to the W / O emulsion, stir at 500-1000r / min for 30-60min to obtain a mixed solution a; (3) crosslinking reaction Add 1-3 parts of chitosan, 0.5-2 parts of glutaraldehyde and 0.1-1 parts of citric acid to the mixed solution a, adjust the pH to 4-6, then react at 40-60℃ for 2-4h to obtain a mixed solution b; (4) film forming treatment Pour the mixed solution b into a flat mold, control the thickness to be 50-100 microns, dry at 50-70℃ for 12-24h to form a wet film; (5) surface modification Soak the wet film in an ethanol solution containing nano zinc oxide, ultrasonic treatment at an ultrasonic power of 300-500W and a frequency of 20-40kHz for 10-15min to form an antibacterial coating, then take it out and dry at room temperature for 2-4h to obtain a dry film; (6) temperature rising treatment Heat the dry film to 100-120℃ at a rate of 2-5℃ / min, keep it at this temperature for 1.5-2h to enhance the mechanical strength, and then naturally cool it to room temperature to obtain the finished product of the membrane for adsorbing aluminum dust.

9. The method of claim 1, wherein the method further comprises: The mass ratio of polyvinyl alcohol and sodium dodecyl benzene sulfonate is (2-5):(0.5-2).

10. The method of claim 1, wherein the method further comprises: The mass concentration of the nano-zinc oxide in the ethanol solution is 0.1-1%.

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