Zero emission method for metal surface treatment

Abstract

The invention relates to a metal surface treatment zero-emission method, which comprises an environment-friendly cleaning agent, an environment-friendly film-forming protective agent, cleaning equipment and baking equipment, the process cancels the traditional washing step, realizes cyclic utilization of the cleaning solution through atomization spraying of the environment-friendly cleaning agent and the film-forming protective agent, effectively avoids generation and emission of a large amount of wastewater, and reduces the production cost. Therefore, the consumption of water resources is greatly reduced, and the requirements of modern environmental protection laws and regulations are met.

Description

Technical Field

[0001] The present invention relates to a zero - emission method for metal surface treatment. Background Art

[0002] In the field of metal manufacturing and processing, metal surface treatment technology has always been a key link in improving product performance, corrosion resistance, and appearance quality. Traditional metal surface treatment processes mainly rely on chemical cleaning and water washing methods. A large amount of water resources are used to wash away impurities such as oil stains, oxide scales, and dust on the metal surface, and anti - rust treatment and coating processes are adopted to form a protective film. However, with the continuous expansion of industrial production scale and the increasingly strict environmental protection requirements, the existing technologies have the following main problems and deficiencies: During the traditional metal surface treatment process, the water washing step occupies an important position. The consumption of a large amount of cleaning water not only significantly increases the production cost, but also causes a large dependence on and waste of fresh water resources. Especially in a large - scale production environment, the high consumption of water resources has become an important factor restricting production efficiency and the economic benefits of enterprises.

[0003] The wastewater generated by the water washing process often contains high - concentration oil stains, chemical cleaning agents, and other pollutants. If directly discharged without sufficient treatment, it will cause serious pollution to the surrounding water bodies, soil, and ecological environment. In recent years, environmental protection regulations in various countries have become increasingly strict. Enterprises not only face increasingly stringent environmental inspections, but also may bear high sewage treatment costs and fine risks due to unqualified wastewater discharge, thus having an adverse impact on the corporate image and market competitiveness.

[0004] In continuous operation, pollutants such as oil stains and dust attached to the metal surface continuously enter the cleaning liquid, resulting in an accelerated liquid pollution rate and a gradual decline in the cleaning effect. In traditional processes, the cleaning liquid needs to be frequently replaced to ensure the cleaning quality, which not only increases the material consumption, but also reduces the continuous operation efficiency of the production line.

[0005] Due to the high degree of pollution of the cleaning liquid, it is difficult for traditional processes to ensure an ideal cleaning state of the metal surface during the cleaning process, thus affecting the adhesion, anti - rust, and anti - corrosion properties of subsequent film - forming or coating processes. Problems such as uneven coating and insufficient weather resistance may occur in the actual application of products, making it difficult to meet the high - standard and refined market demands. Summary of the Invention

[0006] The purpose of the present invention is to provide a zero - emission method for metal surface treatment that can efficiently clean the oil stains on the metal surface, form a film for protection, and recycle the cleaning liquid, thereby effectively solving the problems of water resource waste, wastewater discharge, and pollution of the treatment liquid in traditional technologies.

[0007] The purpose of the present invention is achieved as follows: A zero-emission method for metal surface treatment, including an environmentally friendly cleaning agent, an environmentally friendly film-forming protective agent, cleaning equipment, and baking equipment. The environmentally friendly cleaning agent includes a surfactant, a chelating agent, a corrosion inhibitor, and deionized water. The surfactant accounts for 30%, the chelating agent accounts for 15%, the corrosion inhibitor accounts for 5%, and the deionized water accounts for 50%. The environmentally friendly film-forming protective agent is composed of silicone resin, a rust inhibitor additive, a solvent, and a curing agent. The silicone resin accounts for 10%, the rust inhibitor additive accounts for 5%, the solvent accounts for 80%, and the curing agent accounts for 5%. The cleaning equipment includes a first spraying device, an ultrasonic demulsification and degreasing machine, a precision filter, and a second spraying device. The first spraying device includes a liquid storage tank and a first spray head, and the first spray head is connected to the liquid storage tank. The second spraying device includes a liquid storage tank and a second spray head, and the second spray head is connected to the liquid storage tank. Zero-emission operation steps for metal surface treatment Step 1: Pour 10% of the environmentally friendly cleaning agent into the liquid storage tank of the first spraying device, adjust the pressure and flow rate of the first spraying device, and the first spray head sprays the cleaning agent onto the metal surface in a uniform mist for 3 to 5 minutes of spraying and cleaning to remove oil and dirt particles and impurities on the metal surface of the workpiece. Step 2: The mixed liquid composed of the oil and dirt particles and the environmentally friendly cleaning agent in Step 1 flows into the cleaning tank of the ultrasonic demulsification and degreasing machine. Step 3: Place the workpiece into the cleaning tank of the ultrasonic demulsification and degreasing machine, add the environmentally friendly cleaning agent to the cleaning tank. The ultrasonic demulsification and degreasing machine uses high-frequency vibration waves to detach the oil and dirt particles from the metal surface of the workpiece and disperse them in the environmentally friendly cleaning agent to form a mixed liquid. Then, the ultrasonic demulsification and degreasing machine uses high-frequency vibration waves to break up the oil and dirt particles in the mixed liquid. Step 4: The mixed liquid in Step 3 flows into the precision filter. The precision filter separates the mixed liquid into hazardous waste and an environmentally friendly cleaning agent through multiple filtering media. The environmentally friendly cleaning agent is recycled and returned to the cleaning tank of the ultrasonic demulsification and degreasing machine, and the hazardous waste is transferred to a third-party professional agency for recycling and treatment. Step 5: Pour the environmentally friendly film-forming protective agent into the liquid storage tank of the second spraying device, take out the workpiece, and atomize and spray the metal surface of the workpiece through the second spray head of the second spraying device until a protective film with a thickness of 0.2 - 2 μm is formed on the metal surface. Step 6: Place the workpiece into the baking equipment and dry the metal surface at 120°C for 15 minutes to cure the protective film.

[0008] This process eliminates the traditional water washing step. Through the atomized spraying of an environmentally friendly cleaning agent and a film-forming protective agent, the recycling of the cleaning liquid is achieved, effectively avoiding the generation and discharge of a large amount of wastewater, thereby significantly reducing the consumption of water resources and meeting the requirements of modern environmental protection regulations.

[0009] Utilizing the high-frequency vibration of an ultrasonic demulsification and oil removal machine, the oil particles on the metal surface can be quickly desorbed and dispersed. In combination with the effective separation of oil and impurities in the mixed liquid by a precision filter, the stability and superiority of the cleaning effect are ensured. At the same time, an environmentally friendly film-forming protective agent forms a uniform and dense protective film on the metal surface, not only significantly improving the rust and corrosion prevention performance of metal products but also providing a good adhesion basis for subsequent painting.

[0010] Since the cleaning liquid is recycled through efficient ultrasonic demulsification and precision filtration technologies, the frequent replacement of the cleaning liquid and the consumption of chemical reagents are reduced, thereby lowering the production cost. In addition, avoiding wastewater discharge also reduces the investment of enterprises in environmental protection governance and potential legal risks, enhancing the market competitiveness of enterprises.

[0011] The object of the present invention can also be solved by the following technical measures: Further, the surfactant is a biodegradable non-ionic surfactant; The chelating agent is ethylenediaminetetraacetic acid that undergoes a chelation reaction with the impurity ions on the metal surface to remove the impurity ions from the metal surface; The corrosion inhibitor is a ferrous metal corrosion inhibitor and a silane coupling agent that can form a protective film on the metal surface to prevent the metal from being corroded during the cleaning process.

[0012] Using a biodegradable non-ionic surfactant helps reduce the generation of persistent organic pollutants during the cleaning process, meets the requirements of green environmental protection, and has less negative impact on the ecological environment.

[0013] Ethylenediaminetetraacetic acid (EDTA) as a chelating agent can effectively chelate with the impurity ions on the metal surface, quickly remove the pollutants attached to the metal surface, improve the cleaning effect, and ensure a higher cleanliness of the metal surface.

[0014] By using a corrosion inhibitor composed of a combination of a ferrous metal corrosion inhibitor and a silane coupling agent, a dense protective film can be formed on the metal surface during the cleaning process, effectively preventing the metal from being corroded due to long-term contact with the cleaning liquid, extending the service life of metal products, and at the same time providing a good base for subsequent protection processes (such as painting).

[0015] The reasonable combination of the three functional components enables the entire cleaning process to not only efficiently remove dirt but also take into account anti-corrosion protection, further ensuring the product quality and performance after metal surface treatment, achieving a comprehensive effect of environmental protection, cleanliness, and high efficiency.

[0016] Furthermore, the silicone resin is a silicone resin with good film-forming properties and weather resistance that can form a tough protective film on the metal surface; The rust inhibitor additive is a silane coupling agent with excellent rust prevention performance; The solvent is an environmentally friendly alcohol solvent and pure water that can dissolve the silicone resin and other additives; The curing agent is an isocyanate that can react with the silicone resin to rapidly cure the protective film.

[0017] Using a silicone resin with good film-forming properties and weather resistance to form a tough protective film on the metal surface can effectively isolate air, moisture, and corrosive media, improving the corrosion resistance and service life of the metal.

[0018] The protective film has high weather resistance, can remain stable in harsh environments (such as high temperature, high humidity, or acid-base environments), is not prone to cracking or peeling, and improves the long-term stability of the coating.

[0019] Using a silane coupling agent as the rust inhibitor additive, its excellent metal-binding ability can further enhance the adhesion of the protective film to the metal substrate, while providing rust prevention performance, preventing metal oxidation and rusting, and improving the protection effect.

[0020] Selecting environmentally friendly alcohol solvents and pure water as solvents avoids the pollution problem of volatile organic compounds (VOCs) in traditional solvent-based coatings, reduces the impact on the environment, and at the same time reduces the health hazards during production and use, meeting the requirements of environmental protection regulations.

[0021] Using isocyanate as the curing agent, it can cross-link with the silicone resin to rapidly cure the protective film, improve the construction efficiency, reduce the workpiece processing time, and contribute to large-scale industrial applications.

[0022] This formulation achieves a balance of film-forming property, weather resistance, rust prevention, environmental protection, and rapid curing, providing an efficient, environmentally friendly, and long-lasting metal surface protection solution, which can be widely applied to the metal protection fields of industries such as machinery, automobiles, and ships.

[0023] Furthermore, the ultrasonic demulsification and oil removal machine includes an ultrasonic generator, a transducer, a cleaning tank, and a control system; The ultrasonic generator generates high-frequency electrical signals, which are transmitted to the transducer through a cable. The transducer converts the high-frequency electrical signals into high-frequency mechanical vibration waves, and the high-frequency mechanical vibration waves are introduced into the cleaning liquid in the cleaning tank. When the high-frequency mechanical vibration waves act on the oil stain particles, the oil stain particles resonate, thereby destroying their adhesion to the metal surface, causing them to fall off from the metal surface and disperse in the cleaning liquid.

[0024] By generating high-frequency mechanical vibration waves through the ultrasonic generator, the oil stain particles resonate, thereby destroying their adhesion to the metal surface, making it easier for the oil stains to fall off from the metal surface and improving the cleaning efficiency.

[0025] Compared with traditional chemical cleaning or mechanical wiping methods, ultrasonic cleaning can penetrate into complex structures or tiny pores, achieve uniform and thorough decontamination, and improve the overall cleanliness of the workpiece.

[0026] Since ultrasonic waves can effectively disperse the oil stain particles, making them easier to fall off from the metal surface and suspend in the cleaning liquid, the dependence on chemical cleaning agents such as strong alkalis and strong acids is reduced, and the risk of waste liquid discharge and environmental pollution is lowered.

[0027] The cleaning liquid can be recycled, further reducing the cleaning cost and the pressure of waste liquid treatment, and realizing a more environmentally friendly metal surface treatment solution.

[0028] Traditional mechanical cleaning may cause scratches or abrasions on the metal surface, while the ultrasonic cleaning method uses non-contact high-frequency vibration waves to act on the oil stains, avoiding physical friction, thereby reducing damage to the workpiece surface and ensuring the integrity of the metal surface.

[0029] Adopting a control system to precisely adjust the ultrasonic frequency, amplitude and cleaning time to achieve intelligent cleaning helps to improve production efficiency and meet the needs of large-scale industrial production.

[0030] This ultrasonic demulsification and oil removal machine is applicable to various metal materials (such as steel, aluminum, copper, etc.) and various types of oil stains (such as machine oil, grease, cutting fluid residues, etc.), and is applicable to the metal surface cleaning processes in multiple fields such as automobile manufacturing, precision electronics, and aerospace.

[0031] Furthermore, the ultrasonic demulsification and oil removal machine also includes a frequency adjustment module. The frequency of the ultrasonic demulsification and oil removal machine is 20 - 40 kHz, the power is 500 - 1000 W, and the working time is 10 - 15 min. The frequency adjustment module can automatically optimize the working frequency of the ultrasonic waves according to the type and degree of contamination of the oil stains on the metal surface.

[0032] Using an adjustable ultrasonic frequency of 20 - 40 kHz, it can be automatically optimized according to the type of oil stains (such as light oil, heavy oil, grease, etc.). For example: Low frequency (20 - 25 kHz): Suitable for removing thick and strongly adherent oil stains, such as grease and coking oil stains on heavy machinery.

[0033] High frequency (30 - 40 kHz): Suitable for removing finer or easily dispersed oil stains, such as cutting fluid residues in machining or light oil films on precision electronic components.

[0034] By precisely matching the cleaning requirements, the cleaning time is reduced and the decontamination efficiency is improved.

[0035] The frequency adjustment module can automatically adjust the power (500 - 1000 W) according to the degree of contamination, avoiding over - cleaning or ineffective energy consumption, thus reducing energy consumption.

[0036] By intelligently controlling the ultrasonic output, the continuous high - load operation of the equipment is reduced, the service life of the equipment is extended, and the maintenance cost is reduced.

[0037] Excessively high ultrasonic frequencies may cause minor damage to some precision metal workpieces, while low frequencies may not clean thoroughly. Through the frequency adjustment module, the best balance can be achieved between cleaning effect and material protection to ensure the integrity of the metal surface.

[0038] Adopting an automatic optimization and adjustment function, manual intervention is reduced, the intelligent level of the cleaning process is improved, and it is suitable for large - scale industrial production.

[0039] Set the optimal working time range of 10 - 15 minutes to ensure uniform and stable cleaning, improve the production rhythm control ability, and enhance the overall production efficiency.

[0040] Suitable for the metal surface cleaning requirements of multiple industries such as aerospace, automotive manufacturing, precision electronics, medical devices, and machining. It can be applied to different materials (such as stainless steel, aluminum alloy, copper, etc.) and different types of oil stain treatment, realizing multi - purpose use of one machine, and enhancing the versatility and economic value of the equipment.

[0041] Furthermore, the precision filter includes a filter tank body and a filter medium that can effectively intercept oil - stain particles and solid impurities. The filter tank body is provided with the liquid inlet, liquid outlet, and sewage outlet. The filter medium is arranged inside the filter tank body, and a liquid inlet valve for controlling the flow rate of the cleaning liquid at 20 - 100 L / min is provided at the liquid inlet; The mixed liquid in step three enters the filter tank body through the liquid inlet, and then after being filtered by the filter medium, the clean environmental protection cleaning agent is discharged to the cleaning tank of the ultrasonic demulsification and oil removal machine through the liquid outlet for recycling, and the hazardous waste is discharged through the sewage outlet.

[0042] Through the high - efficiency filter medium, oil - stain particles and solid impurities can be effectively intercepted, ensuring that the cleaning agent still has good cleaning ability after filtration.

[0043] The filtered environmentally friendly cleaning agent flows back from the liquid outlet to the cleaning tank of the ultrasonic demulsification and oil removal machine, realizing the recycling of the cleaning agent, reducing the consumption of the cleaning agent, thus reducing the production cost of the enterprise and reducing the replenishment frequency of the new cleaning agent.

[0044] An inlet valve with an adjustable flow rate of 20 - 100 L / min is adopted, which can accurately control the flow rate according to different cleaning requirements and optimize the filtering effect: Low flow rate (20 - 50 L / min): Suitable for deep filtration of high-viscosity oil stains and fine impurities, improving the decontamination accuracy.

[0045] High flow rate (50 - 100 L / min): Suitable for large-flow cleaning requirements, ensuring high efficiency in industrial production.

[0046] The filtered cleaning agent has a high cleanliness, ensuring excellent decontamination ability during recycling and improving the cleaning quality of the metal surface.

[0047] During the filtration process, the oil stains and solid impurities in the cleaning liquid are intercepted and collected, and finally discharged from the sewage outlet, ensuring the centralized collection and treatment of hazardous waste and preventing it from mixing into the recycled cleaning agent to cause secondary pollution.

[0048] By transferring the hazardous waste to a third-party professional agency for recycling and treatment, the impact of industrial production on the environment is reduced, meeting the requirements of environmental protection regulations and improving the green manufacturing level of the enterprise.

[0049] The filter tank design is adopted to prevent the filter medium from failing or being damaged due to high pressure or high-speed flow, improving the stability and service life of the filtration system.

[0050] By reasonably designing the fluid distribution structure of the inlet, outlet and sewage outlet, it is ensured that the cleaning liquid passes through the filter medium evenly, preventing local blockage or a decrease in filtration efficiency.

[0051] The filter medium can be replaced or upgraded according to application requirements, suitable for the separation of different types of oil stain particles and solid impurities, and is widely used in the metal surface cleaning processes of industries such as automobile manufacturing, machining, aerospace, and electronics manufacturing.

[0052] The adjustable inlet flow rate makes it suitable for cleaning requirements of different scales and different pollution degrees, improving the adaptability and economic value of the equipment.

[0053] Further, after step four is completed, check the concentration of the environmentally friendly cleaning agent discharged from the precision filter. When the concentration of the environmentally friendly cleaning agent is lower than 50%, stop the circulation to the cleaning tank of the ultrasonic demulsification and oil removal machine, drain the environmentally friendly cleaning agent in the cleaning tank of the ultrasonic demulsification and oil removal machine, and then refill the environmentally friendly cleaning agent.

[0054] Through the concentration monitoring mechanism, when the concentration of the cleaning agent is lower than 50%, the system automatically stops its recycling to prevent the decline of cleaning ability, ensure that the oil stains, particles and impurities on the workpiece surface can be fully removed, and improve the cleaning quality.

[0055] Re-filling the environmentally friendly cleaning agent can ensure that highly efficient cleaning agents are always used during the metal surface treatment process, avoiding problems such as secondary pollution or incomplete cleaning caused by low-efficiency cleaning agents.

[0056] When the concentration of the cleaning agent is too low, continued use will cause the accumulation of oil stains and impurities, increase the burden on the filtration equipment, and accelerate the blockage or loss of the filter medium.

[0057] Timely replacement of low-efficiency cleaning agents reduces the load on the ultrasonic demulsification and oil removal machine and the precision filter, extends their service life, and reduces equipment maintenance costs.

[0058] Low-concentration cleaning agents often require longer time and higher ultrasonic power to achieve the same cleaning effect, thus increasing energy consumption.

[0059] Through the concentration detection and cleaning agent replacement mechanism, it can ensure that the equipment always operates in the best working state, improve energy efficiency, and reduce unnecessary energy consumption.

[0060] Low-concentration cleaning agents may contain a large number of dispersed oil stain particles. If recycled, it may lead to increased internal pollution of the cleaning equipment and even make the waste liquid difficult to treat.

[0061] Timely replacement of the cleaning agent can ensure the separation efficiency of the precision filter, reduce the accumulation of harmful substances, reduce the emission of hazardous waste, meet the requirements of environmental protection regulations, and improve the green production level of the enterprise.

[0062] This solution can be combined with an automatic monitoring and control system to realize real-time detection and automatic replacement of the cleaning agent concentration, reduce manual intervention, improve the automation degree of the production line, reduce manual operation errors, and improve production efficiency.

[0063] Furthermore, it also includes an online sensor and a central control system. The cleaning equipment and the baking equipment are respectively electrically connected to the central control system. The online sensor monitors the concentration of the environmentally friendly cleaning agent and transmits the detection data to the central control system. The central control system issues a replacement signal when the concentration of the environmentally friendly cleaning agent is lower than the preset threshold.

[0064] By adopting an online sensor and a central control system, the concentration of the environmentally friendly cleaning agent is monitored in real time, and a replacement signal is automatically issued when the concentration is lower than the preset threshold, making the entire cleaning process more stable and intelligent, facilitating large-scale continuous production, and further improving production efficiency and product consistency.

[0065] Realize real-time monitoring of the cleaning agent concentration to ensure stable cleaning effect Through an online sensor, the system can continuously monitor the concentration of the cleaning liquid, avoiding the uncertainty and delay of manual detection and improving the accuracy of data.

[0066] Automatically judge the status of the cleaning agent. When the concentration is lower than the set threshold, the system immediately sends a replacement signal to prevent the cleaning quality from being affected due to the failure of the cleaning agent and ensure that the surface of the workpiece always maintains a high cleanliness.

[0067] Traditional replacement of the cleaning agent relies on manual monitoring and experience judgment, which is prone to cause lag in judgment or untimely replacement.

[0068] Through the automated management of the central control system, human error operations can be reduced, the degree of intelligence in the production process can be improved, and the cleaning process can be made more efficient and stable.

[0069] Precisely control the timing of cleaning agent replacement, avoiding waste of cleaning agent caused by premature replacement and also preventing the decline of cleaning ability caused by too late replacement, effectively extending the service life of the cleaning agent.

[0070] Optimize resource allocation, reduce unnecessary replenishment of cleaning agent and waste liquid discharge, reduce production costs and improve economic benefits.

[0071] Long-term use of low-efficiency cleaning agents may lead to the accumulation of oil stains inside the equipment, increasing the burden on the ultrasonic demulsification and oil removal machine and the precision filter, affecting their normal operation.

[0072] Through intelligent concentration management, it can ensure that the cleaning equipment is always in the best working state, reduce problems such as equipment blockage and overloading operation, thereby extending the equipment life and reducing maintenance costs.

[0073] The central control system can record the concentration change trend of the cleaning agent, providing data support for production optimization, fault troubleshooting and quality management.

[0074] Combined with the concept of intelligent manufacturing, remote monitoring and maintenance can be realized, improving the digital management level of the enterprise and enhancing the refined control of the production process.

[0075] By precisely controlling the replacement of the cleaning agent, overuse and frequent abandonment are avoided, reducing the discharge of hazardous waste from the source, meeting the requirements of environmental protection regulations and enhancing the green production capacity of the enterprise.

[0076] The online monitoring system ensures the best timing for the recycling of the cleaning agent, reduces environmental pollution and promotes sustainable development.

[0077] Furthermore, the environmentally friendly film-forming protective agent further contains one or more corrosion inhibitors that further improve the corrosion resistance of the metal surface, and the corrosion inhibitors are selected from silanes, phosphates or tannin compounds.

[0078] Although traditional silicone resin protective films can provide basic protection, there is still a certain corrosion risk in harsh environments such as high humidity and high salt spray.

[0079] By adding corrosion inhibitors additionally, this solution can actively inhibit the corrosion reaction on the metal surface, provide more durable protection in corrosive environments such as acids, alkalis, and salts, and extend the service life of the metal.

[0080] Silane-based corrosion inhibitors: Can form chemical bonds with the metal surface to form a dense silicon-oxygen network structure, enhancing the water resistance and corrosion resistance of the coating.

[0081] Phosphate-based corrosion inhibitors: Can form an insoluble phosphate protective layer on the metal surface, reducing the erosion of oxygen and corrosive media, and are widely used for the protection of easily corroded metals such as steel.

[0082] Tannin compounds: Can undergo chelation reactions with metal ions to form a stable metal-tannin composite layer, preventing the intrusion of corrosive media, and are suitable for the protection of non-ferrous metals.

[0083] By using different types of corrosion inhibitors in combination, a synergistic protection effect can be formed to further optimize the overall protection performance of the film-forming protective agent.

[0084] While traditional rust inhibitors improve corrosion resistance, they may affect the film-forming quality, resulting in a decrease in the adhesion of the protective layer.

[0085] By optimizing the types and proportions of corrosion inhibitors, ensuring good compatibility with silicone resin, it will not affect the uniformity and adhesion of the protective layer, and guarantee the long-term stability of the coating.

[0086] This solution is applicable to the protection of metals in humid, high salt spray, acidic or alkaline environments, and can be widely used in fields such as ships, automobiles, buildings, mechanical equipment, and aerospace.

[0087] It is especially suitable for metal materials such as steel, aluminum alloy, and stainless steel, enhancing their durability in complex environments and reducing maintenance costs.

[0088] The selected silanes, phosphates, and tannin compounds are all environmentally friendly anti-corrosion additives, which are more environmentally friendly than traditional heavy metal corrosion inhibitors (such as chromates, nitrites, etc.), non-toxic or low-toxic, and reduce environmental pollution.

[0089] It can be used in combination with water-based environmentally friendly solvents to avoid the emission of volatile organic compounds (VOCs), meet the requirements of modern green manufacturing, and contribute to the sustainable development of enterprises.

[0090] Furthermore, the water contact angle of the protective film is greater than 90°.

[0091] A water contact angle greater than 90° indicates that the surface is hydrophobic. Water droplets are difficult to spread on the surface and form spherical droplets that roll off, reducing the residence time of moisture on the metal surface.

[0092] This effectively reduces water penetration, reduces the risk of metal exposure to corrosive media such as moisture, acid rain, and salt spray, and improves the overall corrosion resistance.

[0093] The hydrophobic surface reduces the possibility of attachment of stains and water-soluble pollutants (such as dust, sediment, salts, etc.).

[0094] When water droplets roll on the surface, they can carry away the attached dirt, forming a self-cleaning function similar to the lotus leaf effect, keeping the metal surface clean and reducing the manual maintenance cost.

[0095] Traditional protective films may age and peel off due to water intrusion when exposed to moisture, high temperature, and ultraviolet environments for a long time.

[0096] The hydrophobic protective film can reduce water absorption, effectively delay the processes of oxidation, aging, and degradation, maintain long-term stability in harsh environments, and extend the service life of metal surface treatment.

[0097] It is applicable to metal equipment (such as ships, bridges, vehicles, aerospacecraft, etc.) in marine environments, humid areas, and high-salt spray regions to enhance their corrosion resistance.

[0098] It can be used for outdoor facilities, building facades, metal roofs, etc. to reduce water stain pollution and improve aesthetics and durability.

[0099] It is applicable to electronic devices, precision instruments, etc. to prevent water vapor condensation, reduce the risk of circuit short circuits, and improve safety.

[0100] By optimizing the material formula (such as adding specific hydrophobic agents or adjusting the chemical structure of silicone resins), efficient hydrophobic effects can be achieved without using fluorides, meeting the requirements of environmental protection and sustainable development.

[0101] The beneficial effects of the present invention are as follows: In the present invention, through the cyclic use of an environmentally friendly cleaning agent, an ultrasonic demulsification and degreasing machine, and a precision filter, the efficient recovery and reuse of the cleaning liquid are realized, avoiding the direct discharge of waste liquid, thereby reducing environmental pollution and meeting the requirements of green manufacturing. In addition, hazardous wastes are effectively separated and transferred to professional institutions for treatment, ensuring compliance with environmental protection regulations and the requirements of sustainable development.

[0102] In the present invention, the method adopts ultrasonic demulsification and oil removal technology. By means of high-frequency vibration waves, the adhesion force of oil stain particles is destroyed, causing them to fall off from the metal surface, significantly improving the cleaning efficiency and quality. At the same time, the equipped frequency adjustment module can automatically optimize the ultrasonic frequency according to the type of oil stain and the degree of pollution, reducing energy consumption while improving the decontamination effect, making the entire cleaning process more efficient and stable.

[0103] In the present invention, in terms of metal surface protection, the method forms a dense protective film on the metal surface through an environmentally friendly film-forming protective agent, enhancing the antioxidant and corrosion resistance. The water contact angle of the protective film is greater than 90°, with excellent hydrophobicity and self-cleaning ability, which can effectively prevent the attachment of moisture and pollutants, improve the long-term service life of metal components, and reduce maintenance costs.

[0104] In the present invention, the method realizes intelligent monitoring and automatic control. Online sensors continuously monitor the concentration of the environmentally friendly cleaning agent and transmit the data to the central control system, automatically sending a replacement signal when the concentration is lower than the preset threshold to ensure the effectiveness of the cleaning solution. At the same time, the precision filter can automatically detect the concentration of the environmentally friendly cleaning agent and stop the circulation and replace it when it is lower than 50% to ensure the stability of the cleaning quality.

[0105] In the present invention, the method has high process adaptability and is suitable for the cleaning and protection of various metal materials. Using biodegradable non-ionic surfactants improves the compatibility with different metal materials and avoids environmental pollution. In addition, the flow rate of the spraying equipment can be adjusted, suitable for workpieces of different shapes and sizes, enabling it to be widely applied in multiple industries such as aerospace, automotive manufacturing, precision instruments, and electronic equipment, meeting the high-standard metal surface treatment requirements. BRIEF DESCRIPTION OF THE DRAWINGS

[0106] Figure 1 It is a schematic flow chart of a zero-emission method for metal surface treatment. DETAILED DESCRIPTION OF THE INVENTION

[0107] The present invention will be further described below in conjunction with the drawings and embodiments: Embodiment, in combination with Figure 1 As shown, a zero-emission method for metal surface treatment includes an environmentally friendly cleaning agent, an environmentally friendly film-forming protective agent, cleaning equipment, and baking equipment. The environmentally friendly cleaning agent includes a surfactant, a chelating agent, a corrosion inhibitor, and deionized water. The surfactant accounts for 30%, the chelating agent accounts for 15%, the corrosion inhibitor accounts for 5%, and the deionized water accounts for 50%. The environmentally friendly film-forming protective agent consists of silicone resin, rust inhibitor additive, solvent and curing agent. The proportion of silicone resin is 10%, the proportion of rust inhibitor additive is 5%, the proportion of solvent is 80%, and the proportion of curing agent is 5%. The cleaning equipment includes a first spraying device, an ultrasonic demulsification and degreasing machine, a precision filter and a second spraying device. The first spraying device includes a liquid storage tank and a first spray head, and the first spray head is connected to the liquid storage tank. The second spraying device includes a liquid storage tank and a second spray head, and the second spray head is connected to the liquid storage tank. Zero-emission operation steps for metal surface treatment Step 1: Pour 10% of the environmentally friendly cleaning agent into the liquid storage tank of the first spraying device, adjust the pressure and flow rate of the first spraying device, and the first spray head sprays the cleaning agent onto the metal surface in a uniform mist for 3 to 5 minutes of spraying and cleaning to remove oil and dirt particles and impurities on the metal surface of the workpiece. Step 2: The mixture of oil and dirt particles and the environmentally friendly cleaning agent in Step 1 flows into the cleaning tank of the ultrasonic demulsification and degreasing machine. Step 3: Place the workpiece into the cleaning tank of the ultrasonic demulsification and degreasing machine, add the environmentally friendly cleaning agent to the cleaning tank. The ultrasonic demulsification and degreasing machine uses high-frequency vibration waves to detach the oil and dirt particles from the metal surface of the workpiece and disperse them in the environmentally friendly cleaning agent to form a mixture. Then, the ultrasonic demulsification and degreasing machine uses high-frequency vibration waves to break up the oil and dirt particles in the mixture. Step 4: The mixture in Step 3 flows into the precision filter. The precision filter separates the mixture into hazardous waste and environmentally friendly cleaning agent through multiple filtration media. The environmentally friendly cleaning agent is recycled and returned to the cleaning tank of the ultrasonic demulsification and degreasing machine, and the hazardous waste is transferred to a third-party professional agency for recycling and treatment. Step 5: Pour the environmentally friendly film-forming protective agent into the liquid storage tank of the second spraying device, take out the workpiece, and atomize and spray the metal surface of the workpiece through the second spray head of the second spraying device until a protective film with a thickness of 0.2 - 2 μm is formed on the metal surface. Step 6: Place the workpiece into the baking equipment and dry the metal surface at 120°C for 15 minutes to cure the protective film.

[0108] Furthermore, the surfactant is a biodegradable non-ionic surfactant. The chelating agent is ethylenediaminetetraacetic acid that undergoes a chelation reaction with impurity ions on the metal surface to remove the impurity ions from the metal surface. The corrosion inhibitor is a ferrous metal corrosion inhibitor and a silane coupling agent that can form a protective film on the metal surface to prevent the metal from being corroded during the cleaning process.

[0109] Further, the silicone resin is a silicone resin with good film-forming properties and weather resistance that can form a tough protective film on the metal surface; The rust inhibitor additive is a silane coupling agent with excellent rust prevention performance; The solvent is an environmentally friendly alcohol solvent and pure water that can dissolve the silicone resin and other additives; The curing agent is an isocyanate that can react with the silicone resin to quickly cure the protective film.

[0110] Further, the ultrasonic demulsification and degreasing machine includes an ultrasonic generator, a transducer, a cleaning tank, and a control system; The ultrasonic generator generates high-frequency electrical signals, which are transmitted to the transducer through a cable. The transducer converts the high-frequency electrical signals into high-frequency mechanical vibration waves, which are introduced into the cleaning liquid in the cleaning tank. When the high-frequency mechanical vibration waves act on the oil stain particles, the oil stain particles resonate, thereby destroying their adhesion to the metal surface and causing them to fall off from the metal surface and disperse in the cleaning liquid.

[0111] Further, the ultrasonic demulsification and degreasing machine further includes a frequency adjustment module. The frequency of the ultrasonic demulsification and degreasing machine is 20 - 40 kHz, the power is 500 - 1000 W, and the working time is 10 - 15 min. The frequency adjustment module can automatically optimize the working frequency of the ultrasonic waves according to the type and degree of pollution of the oil stain on the metal surface.

[0112] Further, the precision filter includes a filter tank body and a filter medium that can effectively intercept oil stain particles and solid impurities. The filter tank body is provided with the liquid inlet, the liquid outlet, and the sewage outlet. The filter medium is arranged in the filter tank body, and the liquid inlet is provided with a liquid inlet valve for controlling the flow rate of the cleaning liquid at 20 - 100 L / min; The mixed liquid in Step 3 enters the filter tank body through the liquid inlet, and then after being filtered by the filter medium, the clean environmental protection cleaning agent is discharged to the cleaning tank of the ultrasonic demulsification and degreasing machine through the liquid outlet for recycling, and the hazardous waste is discharged through the sewage outlet.

[0113] Further, after Step 4 is completed, check the concentration of the environmental protection cleaning agent discharged from the precision filter. When the concentration of the environmental protection cleaning agent is lower than 50%, stop circulating it to the cleaning tank of the ultrasonic demulsification and degreasing machine, discharge the environmental protection cleaning agent in the cleaning tank of the ultrasonic demulsification and degreasing machine, and then refill the environmental protection cleaning agent.

[0114] Further, it also includes an on-line sensor and a central control system. The cleaning device and the baking device are respectively electrically connected to the central control system. The on-line sensor monitors the concentration of the environmentally friendly cleaning agent and transmits the detection data to the central control system. The central control system issues a replacement signal when the concentration of the environmentally friendly cleaning agent is lower than a preset threshold value.

[0115] Further, the environmentally friendly film-forming protective agent also contains one or more corrosion inhibitors for further improving the corrosion resistance of the metal surface. The corrosion inhibitor is selected from silanes, phosphates or tannin compounds.

[0116] Further, the water contact angle of the protective film is greater than 90°.

Claims

1. A zero-emission method for metal surface treatment, comprising an environmentally friendly cleaning agent, an environmentally friendly film-forming protective agent, a cleaning device and a baking device, characterized in that: The environmentally friendly cleaning agent includes a surfactant, a chelating agent, a corrosion inhibitor and deionized water, wherein the surfactant accounts for 30%, the chelating agent accounts for 15%, the corrosion inhibitor accounts for 5%, and the deionized water accounts for 50%; The environmentally friendly film-forming protective agent comprises an organic silicone resin, an anti-rust additive, a solvent and a curing agent, wherein the organic silicone resin accounts for 10%, the anti-rust additive accounts for 5%, the solvent accounts for 80%, and the curing agent accounts for 5%; The cleaning equipment includes a first spraying device, an ultrasonic demulsifying and oil removing machine, a precision filter, and a second spraying device, wherein the first spraying device includes a liquid storage tank and a first nozzle, and the first nozzle is connected to the liquid storage tank, and the second spraying device includes a liquid storage tank and a second nozzle, and the second nozzle is connected to the liquid storage tank; Zero emission operation steps for metal surface treatment, Step 1: Pour 10% of the environmentally friendly cleaning agent into the liquid storage tank of the first spraying device, adjust the pressure and flow of the first spraying device, and the first nozzle sprays the cleaning agent onto the metal surface in a uniform mist form for 3 to 5 minutes to remove oil particles and impurities on the metal surface of the workpiece; Step 2: The oil particles in step 1 and the environmentally friendly cleaning agent form a mixed liquid that flows into the cleaning tank of the ultrasonic demulsification and oil removal machine; Step 3: Place the workpiece into the cleaning tank of the ultrasonic demulsification and deoiling machine, add environmentally friendly cleaning agent into the cleaning tank, and the ultrasonic demulsification and deoiling machine uses high-frequency vibration waves to remove oil particles from the metal surface of the workpiece and disperse them in the environmentally friendly cleaning agent to form a mixed liquid. Then the ultrasonic demulsification and deoiling machine uses high-frequency vibration waves to break up the oil particles in the mixed liquid; Step 4: The mixed liquid in step 3 flows into a precision filter, which separates the mixed liquid into hazardous waste and environmentally friendly cleaning agent through multi-layer filter media. The environmentally friendly cleaning agent is recycled and circulated into the cleaning tank of the ultrasonic demulsifier and oil remover, and the hazardous waste is transferred to a third-party professional organization for recycling and treatment; Step 5: Pour the environmentally friendly film-forming protective agent into the liquid storage tank of the second spraying device, take out the workpiece, and atomize and spray the metal surface of the workpiece through the second nozzle of the second spraying device until a protective film with a thickness of 0.2-2 μm is formed on the metal surface; Step 6: Place the workpiece in a baking device and dry the metal surface at 120°C for 15 minutes to solidify the protective film.

2. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The surfactant is a biodegradable nonionic surfactant; The chelating agent is ethylenediaminetetraacetic acid which undergoes a chelating reaction with impurity ions on the metal surface to remove the impurity ions from the metal surface; The corrosion inhibitor is a black metal corrosion inhibitor and a silane coupling agent which can form a protective film on the metal surface to prevent the metal from being corroded during the cleaning process.

3. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The organic silicone resin is an organic silicone resin that can form a tough protective film on the metal surface and has good film-forming properties and weather resistance; The anti-rust additive is a silane coupling agent with excellent anti-rust performance; The solvent is an environmentally friendly alcohol solvent and pure water that can dissolve silicone resin and other additives; The curing agent is isocyanate which can react with the silicone resin to rapidly cure the protective film.

4. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The ultrasonic demulsification and oil removal machine comprises an ultrasonic generator, a transducer, a cleaning tank and a control system; The ultrasonic generator generates a high-frequency electrical signal, which is transmitted to the transducer through a cable. The transducer converts the high-frequency electrical signal into a high-frequency mechanical vibration wave, which is transmitted into the cleaning liquid in the cleaning tank. When the high-frequency mechanical vibration wave acts on the oil particles, the oil particles resonate, thereby destroying their adhesion to the metal surface, causing them to fall off the metal surface and disperse in the cleaning liquid.

5. The zero-emission method for metal surface treatment according to claim 4, characterized in that: The ultrasonic demulsification and oil removal machine also includes a frequency adjustment module. The frequency of the ultrasonic demulsification and oil removal machine is 20-40kHz, the power is 500-1000W, and the working time is 10-15min. The frequency adjustment module can automatically optimize the ultrasonic working frequency according to the type and degree of oil pollution on the metal surface.

6. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The precision filter comprises a filter tank body and a filter medium capable of effectively intercepting oil particles and solid impurities, the filter tank body is provided with the liquid inlet, the liquid outlet and the sewage outlet, the filter medium is arranged in the filter tank body, and the liquid inlet is provided with a liquid inlet valve for controlling the flow rate of the cleaning liquid at 20-100 L / min; The mixed liquid in step three enters the filter tank through the liquid inlet, and then is filtered by the filter medium. The clean environmentally friendly cleaning agent is discharged to the liquid outlet to the cleaning tank of the ultrasonic demulsification and oil removal machine for recycling, and the hazardous waste is discharged to the sewage outlet.

7. The zero-emission method for metal surface treatment according to claim 1, characterized in that: After completing step 4, check the concentration of the environmentally friendly cleaning agent discharged from the precision filter. When the concentration of the environmentally friendly cleaning agent is lower than 50%, stop circulating to the cleaning tank of the ultrasonic demulsification and oil removal machine, discharge the environmentally friendly cleaning agent in the cleaning tank of the ultrasonic demulsification and oil removal machine, and then refill the environmentally friendly cleaning agent.

8. The zero-emission method for metal surface treatment according to claim 1, characterized in that: It also includes an online sensor and a central control system. The cleaning equipment and the baking equipment are electrically connected to the central control system respectively. The online sensor monitors the concentration of the environmentally friendly cleaning agent and transmits the detection data to the central control system. The central control system sends a replacement signal when the concentration of the environmentally friendly cleaning agent is lower than a preset threshold based on the detection data.

9. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The environmentally friendly film-forming protective agent also contains one or more corrosion inhibitors for further improving the anti-corrosion performance of the metal surface. The corrosion inhibitors are selected from silane, phosphate or tannin compounds.

10. The zero-emission method for metal surface treatment according to claim 1, characterized in that: The water contact angle of the protective film is greater than 90°.

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