A cleaning and purifying system and method for high-grade surface automotive panels

Abstract

The application relates to a pretreatment equipment technical field of automobile plates, in particular to a cleaning and purifying system and method for high-grade surface automobile plates; the system comprises a composite filter part, a hot rinsing circulating tank and at least two groups of composite filters, a magnetic induction coil and a magnetic medium net are arranged in the composite filter, the magnetic induction coil is arranged at the periphery of the magnetic medium net; the liquid outlet of the hot rinsing circulating tank is communicated with the liquid inlet of the composite filter; a backwashing part comprises a cellulose liquid preparation unit, a buffer unit and a backwashing filter, the discharge port of the cellulose liquid preparation unit is communicated with the feeding port of the backwashing filter, the liquid outlet of the composite filter is communicated with the liquid inlet of the buffer unit, and the liquid outlet of the buffer unit is communicated with the liquid inlet of the backwashing filter; a backwashing filter cloth is arranged in the backwashing filter. The cleaning and purifying system can effectively complete the synchronous separation of iron impurities and oil, so that the cleaning efficiency of the iron impurities and the oil in the degreasing and cleaning process can be improved.

Description

Technical Field

[0001] This application relates to the field of pretreatment equipment technology for automotive panels, and more particularly to a cleaning and purification system and method for high-grade surface automotive panels. Background Technology

[0002] High-quality exterior surfaces are key elements in enhancing the overall quality and brand image of automobiles, leading automakers to impose increasingly stringent requirements on the surface grades of automotive body panels needed for manufacturing. Therefore, how to achieve green production of high-quality automotive body panels using advanced, low-energy-consumption, and low-pollution technologies is a pressing production method that needs to be considered. Closely related to the surface quality of automotive body panels is the steel sheet used in their manufacture. Improving the surface quality of automotive body panels requires degreasing and cleaning the steel strip to remove residual iron powder and grease from its surface. Currently, the entire degreasing and cleaning process consists of spray brushing, electrolytic cleaning, hot water brushing, hot water rinsing, and a cleaning and purification system. After degreasing and alkaline cleaning, the iron powder concentration in the alkaline solution is ≤1000mg / L, and the oil concentration is ≤1%. Currently, cleaning and purification systems generally use permanent magnet chain filters. After the alkaline solution used to clean the steel strip passes through the permanent magnet chain, the iron powder and grease in the alkaline solution are adsorbed onto the permanent magnet. The treated alkaline solution is then filtered and returned to the alkaline solution tank for recycling. In addition, the oil-coated iron adsorbed on the permanent magnet chain is scraped off by the scraper and discharged into the energy medium through the action of the magnetic chain.

[0003] However, permanent magnet chain filters struggle to clean the iron powder off the magnetic chains, and their grease-removing effect is poor. This leads to frequent clogging of the return filter, which increases the impurity content in the recycled alkaline solution, thus affecting the iron powder removal rate from the automotive panels. Furthermore, the persistent poor cleaning effect renders the permanent magnet filter almost ineffective at removing grease, resulting in the accumulation of large amounts of sludge within the equipment. This sludge buildup necessitates the periodic discharge of large quantities of degreasing solution to remove grease and impurities, increasing degreasing solution consumption, the difficulty of industrial wastewater treatment, and the costs and environmental burden of degreasing and cleaning automotive panels, failing to meet current green manufacturing standards. Moreover, the cleanliness of the degreasing solution is difficult to guarantee, easily causing various blemishes and quality defects on the automotive panel surface, thereby increasing the number of re-evaluations required. Summary of the Invention

[0004] This application provides a cleaning and purification system and method for high-grade automotive panels to solve the following technical problem: how to improve the removal efficiency of iron powder and grease during the degreasing cleaning process.

[0005] In a first aspect, this application provides a cleaning and purification system for high-grade automotive panels, the system comprising:

[0006] The composite filtration unit includes a hot rinsing circulation tank and at least two sets of composite filters. The composite filters are equipped with magnetic induction coils and magnetically conductive media meshes. The magnetic induction coils are located around the magnetically conductive media meshes to form an omnidirectional magnetic space. The outlet of the hot rinsing circulation tank is connected to the inlet of the composite filters to rinse impurities from the magnetically conductive media meshes.

[0007] The backwashing unit includes a cellulose solution preparation unit, a buffer unit, and a backwashing filter. The outlet of the cellulose solution preparation unit is connected to the inlet of the backwashing filter, the outlet of the composite filter is connected to the inlet of the buffer unit, and the outlet of the buffer unit is connected to the inlet of the backwashing filter.

[0008] The backwash filter is equipped with a backwash filter cloth.

[0009] Optionally, the composite filtration unit further includes an alkali spray circulation tank and an electrolysis circulation tank, wherein the outlet and inlet of the alkali spray circulation tank are respectively connected to one set of the composite filters; and the outlet and inlet of the electrolysis circulation tank are respectively connected to another set of the composite filters.

[0010] Optionally, the buffer unit includes at least two buffer tanks, the inlet of which is connected to the outlet of the composite filter, and the outlet of which is connected to the inlet of the backwash filter.

[0011] Optionally, the cellulose dispensing unit includes a dispensing tank and a cellulose pre-coating tank. The outlet of the dispensing tank is connected to the inlet of the cellulose pre-coating tank, and the inlet of the cellulose pre-coating tank is connected to the inlet of the backwash filter. The outlet of the dispensing tank is also connected to the inlet of the buffer tank.

[0012] Secondly, this application provides a cleaning and purification method for high-grade automotive panels, the cleaning and purification method being adapted to the cleaning and purification system described in the first aspect, the cleaning and purification method comprising:

[0013] The strip steel is sprayed and washed with alkaline solution to obtain the first waste liquid and the primary strip steel.

[0014] The primary strip steel is electrolytically cleaned using an alkaline solution to obtain a second waste liquid and a strip steel product, respectively.

[0015] Under a preset magnetic field strength, a magnetically conductive medium mesh is used to circulate and filter the first waste liquid and the second waste liquid to adsorb oil and iron powder from the first waste liquid and the second waste liquid, respectively, to obtain a first impurity medium mesh, a second impurity medium mesh and a circulating alkaline solution.

[0016] The first impurity media screen and the second impurity media screen are backwashed with rinsing water to remove oil and iron powder from the first impurity media screen and the second impurity media screen, and backwash waste liquid is obtained.

[0017] The backwash waste liquid and the filter aid solution are mixed to obtain a mixed waste liquid;

[0018] The backwash filter cloth is pre-coated to obtain a pre-treated backwash filter cloth;

[0019] The mixed waste liquid is batch filtered using the pretreated backwash filter cloth to obtain filtrate and filter residue respectively.

[0020] The filtrate and the filter residue are respectively post-processed to obtain effluent and sludge.

[0021] Optionally, the preset magnetic field strength is ≥3000Gs, and the target particle size of the adsorption filtration is ≥1μm.

[0022] Optionally, the conductivity of the rinsing water is ≤50S / m, and the temperature of the rinsing water is 45℃~80℃.

[0023] Optionally, the temperature of the batch filtration is ≤90°C, and the pressure of the batch filtration is ≤6 bar.

[0024] Optionally, the pre-coating of the backwash filter cloth to obtain a pretreated backwash filter cloth includes the following steps:

[0025] The cellulose and demineralized water are mixed to obtain a concentrated cellulose solution;

[0026] The cellulose concentrate is mixed with the demineralized water to obtain a pre-coating solution;

[0027] The backwash filter cloth is pre-coated with the pre-coating solution so that the cellulose in the pre-coating solution adheres to the backwash filter cloth, thereby obtaining a pre-treated backwash filter cloth.

[0028] Wherein, the weight m1 of cellulose in the cellulose concentrate and the weight m2 of the cellulose concentrate satisfy the relationship: m1:m2=0.1:1~0.3:1;

[0029] The weight m2 of the cellulose concentrate in the pre-coating solution and the weight m3 of the pre-coating solution satisfy the relationship: m2:m3 = 0.03:1 to 0.08:1;

[0030] The amount of pre-coating solution applied to the pre-treated backwash filter cloth is 1.0 kg / m². 2 ~1.5kg / m 2 .

[0031] Optionally, the step of post-treating the filtrate and the filter residue to obtain effluent and sludge includes the following steps:

[0032] The filtrate is compressed and discharged to obtain a clear liquid;

[0033] The filter residue is backflushed to obtain sludge;

[0034] The compressed air venting and the backflushing both use compressed air as the medium, and the pressure of the compressed air is 4 kPa to 7 kPa.

[0035] The technical solutions provided in this application have the following advantages compared with the prior art:

[0036] This application provides a cleaning and purification system for high-grade automotive panels. The system includes: a composite filtration unit, comprising a hot rinsing circulation tank and at least two sets of composite filters. Each composite filter contains a magnetic induction coil and a magnetically conductive medium mesh. The magnetic induction coil is located around the magnetically conductive medium mesh to form a omnidirectional magnetic space. The outlet of the hot rinsing circulation tank is connected to the inlet of the composite filters to rinse impurities from the magnetically conductive medium mesh. A backwashing unit includes a cellulose dispensing unit, a buffer unit, and a backwashing filter. The outlet of the cellulose dispensing unit is connected to the inlet of the backwashing filter, the outlet of the composite filters is connected to the inlet of the buffer unit, and the outlet of the buffer unit is connected to the inlet of the backwashing filter. The backwashing filter contains a backwashing filter cloth. The system first utilizes two sets of composite filters to complete two steps: spray washing and electrolytic cleaning of the steel strip. Then, a omnidirectional magnetic space generated by a magnetic induction coil is used to cause iron impurities in the alkaline solution obtained from spray washing and electrolytic cleaning to be uniformly and orderly arranged on the surface of the magnetically conductive medium mesh and magnetized by the omnidirectional magnetic space. This forms a sufficient amount of magnetic flocculation with a loose and porous structure on the surface of the magnetically conductive medium mesh. The sufficient amount of magnetic flocculation can effectively adsorb iron impurities and grease from the alkaline solution, thus allowing the alkaline solution to be recovered and reused. Then, the rinsing water in the hot rinsing circulation tank is used to circulate and rinse the iron impurities and grease adsorbed on the surface of the magnetically conductive medium mesh to remove them. In addition, a cellulose solution preparation unit and a buffer unit are used to prepare a pre-coating solution, which is then used to pre-coat the backwash filter cloth in the backwash filter. The buffer unit then holds the rinse water after rinsing, and the backwash filter cloth, which has been re-pre-coated, is used for batch filtration to effectively complete the simultaneous separation of iron impurities and grease, thereby improving the cleaning efficiency of iron impurities and grease during the degreasing process. Attached Figure Description

[0037] The accompanying drawings, which are incorporated in and form part of this specification, illustrate embodiments consistent with this application and, together with the description, serve to explain the principles of this application.

[0038] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, for those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0039] Figure 1 A schematic diagram of the logical structure of a cleaning and purification system for high-grade automotive panels provided in this application embodiment;

[0040] Figure 2 A schematic diagram of the actual structure of a cleaning and purification system for high-grade automotive panels provided in this application embodiment;

[0041] Figure 3 A schematic diagram of a cleaning and purification method for high-grade automotive panels provided in this application embodiment;

[0042] Figure 4 A detailed flowchart illustrating a cleaning and purification method for high-grade automotive panels provided in this application embodiment;

[0043] Figure 5 This is a macroscopic schematic diagram of the strip steel products produced by the cleaning and purification system provided in Embodiment 3 of this application in conjunction with the strip steel production system.

[0044] Figure 6 A macroscopic schematic diagram of the strip steel products produced by the cleaning and purification system provided in Comparative Example 1 of this application in conjunction with the strip steel production system;

[0045] Figure 7 This is a schematic diagram of the microstructure of the strip steel product produced by the cleaning and purification system provided in Embodiment 3 of this application in conjunction with the strip steel production system.

[0046] Figure 8 A schematic diagram of the microstructure of the strip steel product produced by the cleaning and purification system provided in Comparative Example 1 of this application in conjunction with the strip steel production system;

[0047] Among them, 1-composite filter, 11-magnetic induction coil, 12-magnetic medium mesh, 2-hot rinsing circulation tank, 3-cellulose solution preparation unit, 31-solution preparation tank, 32-cellulose pre-coating tank, 4-buffer unit, 41-buffer tank, 5-backwash filter, 51-backwash filter cloth, 6-alkali spray circulation tank, 7-electrolysis circulation tank. Detailed Implementation

[0048] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of the embodiments of this application will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of this application, not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0049] Various embodiments of this application may exist in the form of a range; it should be understood that the description in the form of a range is merely for convenience and brevity and should not be construed as a hard limitation on the scope of this application; therefore, it should be considered that the range description has specifically disclosed all possible sub-ranges and single numerical values ​​within that range; for example, it should be considered that the range description from 1 to 6 has specifically disclosed sub-ranges such as from 1 to 3, from 1 to 4, from 1 to 5, from 2 to 4, from 2 to 6, from 3 to 6, etc., and single numbers within the range such as 1, 2, 3, 4, 5, and 6, regardless of the range; in addition, whenever a numerical range is indicated herein, it means including any referenced number (fraction or integer) within the indicated range.

[0050] In this document, terms such as “comprising” mean “including but not limited to”. Relational terms such as “first” and “second” are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. “And / or” describes the relationship between related objects, indicating that there can be three relationships, for example, A and / or B can mean: A exists alone, A and B exist simultaneously, or B exists alone; where A and B can be singular or plural. “At least one” means one or more, “more” means two or more; “at least one,” “at least one of the following,” or similar expressions refer to any combination of these items, including any combination of single or plural items; for example, “at least one of a, b, or c,” or “at least one of a, b, and c,” can both mean: a, b, c, ab (i.e., a and b), ac, bc, or abc, where a, b, and c can be single or multiple. Unless otherwise specified, all raw materials, reagents, instruments and equipment used in this application can be purchased from the market or prepared by existing methods.

[0051] Figure 1 An exemplary schematic diagram of the logical structure of a cleaning and purification system for high-grade automotive panels provided in an embodiment of this application is shown.

[0052] Figure 2An exemplary schematic diagram of the actual structure of a cleaning and purification system for high-grade automotive panels provided in an embodiment of this application is shown.

[0053] like Figure 1 and Figure 2 As shown in the figure, this application embodiment provides a cleaning and purification system for high-grade automotive panels, the system comprising:

[0054] A composite filter unit includes a hot rinsing circulation tank 2 and at least two sets of composite filters 1. Each composite filter 1 is provided with a magnetic induction coil 11 and a magnetically conductive medium mesh 12. The magnetic induction coil 11 is located around the magnetically conductive medium mesh 12 to form an omnidirectional magnetic space. The outlet of the hot rinsing circulation tank 2 is connected to the inlet of the composite filter 1 to rinse the impurities in the magnetically conductive medium mesh 12.

[0055] The backwashing section includes a cellulose solution preparation unit 3, a buffer unit 4, and a backwashing filter 5. The outlet of the cellulose solution preparation unit 3 is connected to the inlet of the backwashing filter 5, the outlet of the composite filter 1 is connected to the inlet of the buffer unit 4, and the outlet of the buffer unit 4 is connected to the inlet of the backwashing filter 5.

[0056] The backwash filter 5 is equipped with a backwash filter cloth 51.

[0057] It should be noted that the omnidirectional magnetic space is set on the periphery of the magnetic medium mesh 12. Based on the magnetic field of the omnidirectional magnetic space, the iron impurities in the alkaline solution obtained from spray washing and electrolytic cleaning adsorbed by the magnetic medium mesh 12 can be arranged in an orderly manner and magnetized to form magnetic flocculation on the surface of the magnetic medium mesh 12. Sufficient magnetic flocculation can effectively adsorb iron impurities and grease in the alkaline solution, so that the alkaline solution can be recovered and reused.

[0058] It should be noted that the omnidirectional magnetic space is generated based on the dense coil, and the magnetic medium mesh 12 is set inside the iron removal barrel of the composite filter 1, while the dense coil is set outside the iron outlet barrel.

[0059] It should be noted that since most iron impurities are coated with grease, when magnetic flocculation adsorbs iron impurities from alkaline solutions, the grease coating the iron impurities can also be adsorbed, thus achieving simultaneous removal of iron impurities and grease.

[0060] It should be noted that the hot rinsing circulation tank 2 can provide sufficient rinsing water for the entire system. Sufficient rinsing water can rinse the magnetic medium mesh 12 that has adsorbed iron impurities and grease, thereby obtaining rinsing wastewater containing iron impurities and grease.

[0061] It should be noted that the working process of the hot rinsing circulation tank 2 includes: after the magnetic medium mesh 12 in the composite filter 1 has adsorbed the iron impurities in the alkaline solution to saturation, the filtration system of the composite filter 1 stops the liquid inlet, disconnects the power supply of the universal magnetic space, closes the liquid inlet valve of the composite filter 1, and then opens the slag discharge valve of the composite filter 1 to drain the residual liquid in the cavity of the composite filter 1 into the alkaline solution recovery pipeline. Then, the alkaline solution recovery pipeline returns the residual liquid to the alkaline spray circulation tank 6 or the electrolysis circulation tank 7. After the emptying is completed, the backwashing of the composite filter 1 begins. During the backwashing process, the composite filter 1 is first rinsed with rinsing water from the hot rinsing circulation tank 2 to promote the discharge of the impurities (generally containing high concentrations of iron powder and oil) adsorbed by the magnetic medium mesh 12 in the composite filter 1 into the buffer tank 41 for storage.

[0062] In some optional embodiments, the composite filter 1 further includes an alkali spray circulation tank 6 and an electrolysis circulation tank 7, wherein the outlet and inlet of the alkali spray circulation tank 6 are respectively connected to one set of the composite filters 1; and the outlet and inlet of the electrolysis circulation tank 7 are respectively connected to another set of the composite filters 1.

[0063] In these embodiments, the composite filter 1 may further include an alkali spray circulation tank 6 and an electrolytic circulation tank 7. The outlet and inlet of the alkali spray circulation tank 6 are respectively connected to a set of composite filters 1. The alkali spray circulation tank 6 can store and supply the alkali solution used for spraying and washing the strip steel to realize the cyclic spray washing process of the strip steel. In addition, the outlet and inlet of the electrolytic circulation tank 7 are respectively connected to another set of composite filters 1. The electrolytic circulation tank 7 can store and supply the alkali solution used for electrolytic cleaning of the strip steel to realize the cyclic electrolytic cleaning process of the strip steel.

[0064] In some optional embodiments, the buffer unit 4 includes at least two buffer tanks 41, the inlet of the buffer tank 41 being connected to the outlet of the composite filter 1, and the outlet of the buffer tank 41 being connected to the inlet of the backwash filter 5.

[0065] In these embodiments, the buffer unit 4 may include at least two buffer tanks 41, with the inlet of the buffer tank 41 connected to the outlet of the composite filter 1, and the outlet of the buffer tank 41 connected to the inlet of the backwash filter 5. The backwash waste liquid can be stored in the buffer tank 41 so that the subsequent backwash waste liquid can be filtered by the backwash filter cloth 51 of the backwash filter 5 to obtain the drain liquid.

[0066] In some optional embodiments, the cellulose dispensing unit 3 includes a dispensing tank 31 and a cellulose pre-coating tank 32. The outlet of the dispensing tank 31 is connected to the inlet of the cellulose pre-coating tank 32, and the inlet of the cellulose pre-coating tank 32 is connected to the inlet of the backwash filter 5. The outlet of the dispensing tank 31 is also connected to the inlet of the buffer tank 41.

[0067] In these embodiments, the cellulose solution preparation unit 3 may include a solution preparation tank 31 and a cellulose pre-coating tank 32. The outlet of the solution preparation tank 31 is connected to the inlet of the cellulose pre-coating tank 32, and the inlet of the cellulose pre-coating tank 32 is connected to the inlet of the backwash filter 5. The concentrated cellulose solution and concentrated brine can be mixed and prepared using the cellulose solution preparation pipe and the cellulose pre-coating tank 32 to obtain a pre-coating solution. The pre-coating solution is then introduced into the backwash filter 5 to complete the pre-coating of the backwash filter cloth 51 inside the backwash filter 5. In addition, the outlet of the solution preparation tank 31 is also connected to the inlet of the buffer tank 41. The filter aid can be introduced after the backwash filter cloth 51 is pre-coated to improve the filtration effect of the backwash waste liquid through the backwash filter cloth 51.

[0068] Figure 3 An exemplary schematic diagram of a cleaning and purification method for high-grade automotive panels provided in an embodiment of this application is shown.

[0069] Based on a general inventive concept, such as Figure 3 As shown in the figure, this application provides a cleaning and purification method for high-grade automotive panels. The cleaning and purification method is adapted to the cleaning and purification system and includes:

[0070] S1. The strip steel is sprayed and washed with alkaline solution to obtain the first waste liquid and the primary strip steel respectively;

[0071] S2. The primary strip steel is electrolytically cleaned using an alkaline solution to obtain a second waste liquid and a strip steel product, respectively;

[0072] S3. Under the condition of a preset magnetic field strength, the first waste liquid and the second waste liquid are circulated and filtered by the magnetic medium mesh 12 to adsorb the oil and iron powder in the first waste liquid and the second waste liquid respectively, so as to obtain the first impurity medium mesh, the second impurity medium mesh and the circulating alkaline solution respectively.

[0073] S4. Use rinsing water to backwash the first impurity media screen and the second impurity media screen respectively to remove oil and iron powder from the first impurity media screen and the second impurity media screen, and obtain backwash waste liquid;

[0074] S5. Mix the backwash waste liquid and the filter aid solution to obtain a mixed waste liquid;

[0075] S6. Pre-coat the backwash filter cloth 51 to obtain a pre-treated backwash filter cloth 51;

[0076] S7. The mixed waste liquid is batch filtered using the pretreated backwash filter cloth 51 to obtain filtrate and filter residue respectively;

[0077] S8. The filtrate and the filter residue are post-processed to obtain effluent and sludge.

[0078] This method is based on the system described above. The specific structure of the system can be referred to in the above embodiments. Since this method adopts some or all of the technical solutions of the above embodiments, it has at least all the beneficial effects brought about by the technical solutions of the above embodiments, which will not be elaborated here.

[0079] It should be noted that the spray washing is mainly used to remove about 80% of the residual iron powder and oil stains on the surface of the strip steel using alkaline solution. At the same time, during the spray washing process, the magnetic medium mesh 12 will adsorb iron impurities and grease in the alkaline solution to promote the recycling of the alkaline solution.

[0080] It should be noted that the purpose of this electrolytic cleaning is to use alkaline solution to remove about 20% of the residual iron powder and oil stains on the surface of the strip steel. At the same time, during the electrolytic cleaning process, the magnetic medium mesh 12 will adsorb iron impurities and grease in the alkaline solution to promote the recycling of the alkaline solution.

[0081] It should be noted that the filter aid solution can be a concentrated cellulose solution.

[0082] In some optional embodiments, the preset magnetic field strength is ≥3000 Gs, and the target particle size of the adsorption filtration is ≥1 μm;

[0083] In these embodiments, the preset magnetic field strength is generally ≥3000Gs, which can enable the omnidirectional magnetic space to have sufficient magnetic force to effectively adsorb iron impurities and grease in the alkaline solution, so that the alkaline solution can be recovered and reused; in addition, the target particle size of adsorption filtration can be ≥1μm, which can effectively block iron impurities in the alkaline solution, so as to enable the magnetic medium mesh to effectively adsorb iron impurities in the alkaline solution.

[0084] In some optional embodiments, the conductivity of the rinsing water is ≤50 S / m, and the temperature of the rinsing water is 45℃~80℃;

[0085] In these embodiments, the conductivity of the rinsing water is generally ≤50S / m, and the temperature of the rinsing water can be 45℃~80℃. The rinsing water can effectively wash away the iron impurities and grease adsorbed on the magnetic medium mesh 12, so as to obtain backwash waste liquid with sufficient iron impurities and grease, which facilitates the subsequent backwash filtration stage.

[0086] The temperature of the rinsing water can be 45℃, 50℃, 55℃, 60℃, 65℃, 70℃, 75℃ or 80℃.

[0087] In some alternative implementations, the temperature of the batch filtration is ≤90°C, and the pressure of the batch filtration is ≤6 bar;

[0088] In these embodiments, the batch filtration temperature can be ≤90°C and the batch filtration pressure is generally ≤6 bar, which can enable the pretreatment backwash filter cloth 51 to effectively adsorb iron impurities and grease in the mixed waste liquid, thereby achieving simultaneous removal of iron impurities and grease.

[0089] Figure 4 An exemplary schematic diagram illustrates a detailed process flow diagram of a cleaning and purification method for high-grade automotive panels provided in an embodiment of this application;

[0090] In some alternative implementations, such as Figure 4 As shown, the pre-coating of the backwash filter cloth to obtain a pretreated backwash filter cloth includes the following steps:

[0091] S601. Mix cellulose and demineralized water to obtain a concentrated cellulose solution;

[0092] S602. The cellulose concentrate is mixed with the demineralized water to obtain a pre-coating solution;

[0093] S603. The backwash filter cloth 51 is pre-coated with the pre-coating liquid so that the cellulose in the pre-coating liquid adheres to the backwash filter cloth, thereby obtaining a pre-treated backwash filter cloth 51.

[0094] Wherein, the weight m1 of cellulose in the cellulose concentrate and the weight m2 of the cellulose concentrate satisfy the relationship: m1:m2=0.1:1~0.3:1;

[0095] The weight m2 of the cellulose concentrate in the pre-coating solution and the weight m3 of the pre-coating solution satisfy the relationship: m2:m3 = 0.03:1 to 0.08:1;

[0096] The amount of pre-coating liquid applied to the pre-treated backwash filter cloth 51 is 1.0 kg / m². 2 ~1.5kg / m 2 .

[0097] In these embodiments, the specific process for pre-coating the backwash filter cloth includes first preparing a cellulose concentrate, then using demineralized water and the cellulose concentrate to prepare a pre-coating solution, and then using the pre-coating solution to pre-coat the backwash filter cloth 51, so as to promote the adhesion of cellulose to the surface of the backwash filter cloth 51 and form a thin filter layer. The presence of the cellulose filter layer can avoid damage to the backwash filter cloth (51) by iron impurities and grease. In addition, the weight m1 of cellulose in the cellulose concentrate and the weight m2 of the cellulose concentrate can satisfy the relationship: m1:m2 = 0.1:1 to 0.3:1, and the weight m2 of cellulose concentrate in the pre-coating solution and the weight m3 of the pre-coating solution can satisfy the relationship: m2:m3 = 0.04:1 to 0.08:1, and the coating amount of the pre-coating solution for pre-treating the backwash filter cloth 51 is 1.0 kg / m. 2 ~1.5kg / m 2 Cellulose can be diluted with desalinated water in a gradient to promote uniform distribution of cellulose in the desalinated water, thereby obtaining a pre-coating solution with uniform solute distribution. This pre-coating solution is convenient for subsequent use to promote uniform dispersion of cellulose on the surface of the backwash filter cloth 51, thus obtaining a pre-treated backwash filter cloth 51 with uniform cellulose dispersion.

[0098] The weights m1 and m2 of cellulose in the cellulose concentrate can satisfy the following relationship: m1:m2 = 0.1:1, 0.2:1 or 0.3:1.

[0099] The weights m2 and m3 of the cellulose concentrate in the pre-coating solution can satisfy the following relationship: m2:m3 = 0.04:1, 0.05:1, 0.06:1 or 0.07:1.

[0100] The pre-coating amount of the pre-coating solution for the pre-treated backwash filter cloth 51 is 1.0 kg / m². 2 1.1kg / m 2 1.2kg / m 2 1.3kg / m 2 1.4kg / m 2 Or 1.5kg / m 2 .

[0101] In some optional embodiments, the post-treatment of the filtrate and the filter residue to obtain effluent and sludge includes the following steps:

[0102] S801. The filtrate is compressed and discharged to obtain a clear liquid;

[0103] S802. Backflushing the filter residue to obtain sludge;

[0104] The compressed air venting and the backflush both use compressed air as the medium, and the pressure of the compressed air is 4 kPa to 7 kPa.

[0105] In these embodiments, compressed air is used as the medium for both the filtrate and the filter residue, and the filtrate and filter residue can be post-treated in sequence to achieve solid-liquid separation. In addition, the pressure of the compressed air can be 4 kPa to 7 kPa, which can ensure that the compressed air has sufficient pressure. Sufficient pressure of compressed air can, on the one hand, promote the discharge of the filtrate from the system, and on the other hand, promote the thorough drying of the filter residue on the backwash filter cloth (51), and facilitate subsequent backflushing.

[0106] The pressure of the compressed air can be 4 kPa, 5 kPa, 6 kPa or 7 kPa.

[0107] The present application is further illustrated below with reference to specific embodiments. Experimental methods in the following embodiments that do not specify specific conditions are generally determined according to industry standards; if no corresponding industry standard exists, they are performed according to general international standards, conventional conditions, or conditions recommended by the manufacturer.

[0108] Example 1

[0109] like Figure 1 and Figure 2 As shown, a cleaning and purification system for high-grade automotive panels includes:

[0110] The composite filtration unit includes a hot rinsing circulation tank 2 and at least two sets of composite filters 1. Each composite filter 1 is provided with a magnetic induction coil 11 and a magnetically conductive medium mesh 12. The magnetic induction coil 11 is located around the magnetically conductive medium mesh 12 to form an omnidirectional magnetic space. The outlet of the hot rinsing circulation tank 2 is connected to the inlet of the composite filter 1 to rinse the impurities in the magnetically conductive medium mesh 12.

[0111] The backwashing section includes a cellulose solution preparation unit 3, a buffer unit 4, and a backwashing filter 5. The outlet of the cellulose solution preparation unit 3 is connected to the inlet of the backwashing filter 5, the outlet of the composite filter 1 is connected to the inlet of the buffer unit 4, and the outlet of the buffer unit 4 is connected to the inlet of the backwashing filter 5.

[0112] The backwash filter 5 is equipped with a backwash filter cloth 51.

[0113] The composite filtration section also includes an alkali spray circulation tank 6 and an electrolysis circulation tank 7. The outlet and inlet of the alkali spray circulation tank 6 are respectively connected to a set of composite filters 1; the outlet and inlet of the electrolysis circulation tank 7 are respectively connected to another set of composite filters 1.

[0114] The buffer unit 4 includes at least two buffer tanks 41. The inlet of the buffer tank 41 is connected to the outlet of the composite filter 1, and the outlet of the buffer tank 41 is connected to the inlet of the backwash filter 5.

[0115] The cellulose dispensing unit 3 includes a dispensing tank 31 and a cellulose pre-coating tank 32. The outlet of the dispensing tank 31 is connected to the inlet of the cellulose pre-coating tank 32, and the inlet of the cellulose pre-coating tank 32 is connected to the inlet of the backwash filter 5. The outlet of the dispensing tank 31 is also connected to the inlet of the buffer tank 41.

[0116] Example 2

[0117] Based on the system content disclosed in Example 1, the system operation process is further optimized:

[0118] like Figure 3 and Figure 4 As shown, a cleaning and purification method for high-grade automotive panels, adapted to a cleaning and purification system, includes:

[0119] S1. The strip steel is sprayed and washed with alkaline solution to obtain the first waste liquid and the primary strip steel respectively;

[0120] S2. The primary strip steel is electrolytically cleaned using an alkaline solution to obtain the second waste liquid and the strip steel product, respectively;

[0121] S3. Under the condition of a preset magnetic field strength, the magnetically conductive medium mesh 12 is used to circulate and adsorb and filter the first waste liquid and the second waste liquid respectively, so as to adsorb the oil and iron powder in the first waste liquid and the second waste liquid, and obtain the first impurity medium mesh, the second impurity medium mesh and the circulating alkaline solution respectively.

[0122] S4. Use rinsing water to backwash the first impurity media screen and the second impurity media screen respectively to remove oil and iron powder from the first impurity media screen and the second impurity media screen, and obtain backwash waste liquid;

[0123] S5. Mix the backwash waste liquid and the filter aid solution to obtain a mixed waste liquid;

[0124] S601. Mix cellulose and demineralized water to obtain a concentrated cellulose solution;

[0125] S602. Mix the concentrated cellulose solution with demineralized water to obtain a pre-coating solution;

[0126] S603. Use a pre-coating solution to pre-coat the backwash filter cloth 51 so that the cellulose in the pre-coating solution adheres to the backwash filter cloth 51, thereby obtaining a pre-treated backwash filter cloth;

[0127] S7. Use pretreated backwash filter cloth 51 to perform batch filtration of the mixed waste liquid to obtain filtrate and filter residue separately;

[0128] S801. Compress and drain the filtrate to obtain a clear liquid;

[0129] S802. Backflushing the filter residue to obtain sludge;

[0130] The weights of cellulose in the cellulose concentrate, m1 and m2, satisfy the following relationship: m1:m2 = 0.1:1 to 0.3:1.

[0131] The weights m2 and m3 of the cellulose concentrate in the pre-coating solution satisfy the relationship: m2:m3 = 0.03:1 to 0.08:1;

[0132] The amount of pre-coating solution applied to the pre-treated backwash filter cloth 51 is 1.0 kg / m². 2 ~1.5kg / m 2 .

[0133] Compressed air is used as the medium for both compression venting and backflushing, with a pressure of 4 kPa to 7 kPa.

[0134] The preset magnetic field strength is ≥3000Gs, and the target particle size for adsorption filtration is ≥1μm.

[0135] The conductivity of the rinsing water is ≤50S / m, and the temperature of the rinsing water is 45℃~80℃.

[0136] The batch filtration temperature is ≤90℃ and the batch filtration pressure is ≤6 bar.

[0137] Example 3

[0138] Based on the system disclosed in Example 1 and the method disclosed in Example 2, the impact on actual production is examined:

[0139] The strip steel production speed was set at 240 m / min, the alkaline solution temperature for spray washing and electrolytic cleaning was controlled at 65℃, and the conductivity of the alkaline solution was measured to be 70 mS / cm. The specific cleaning process included:

[0140] 1. Powering on: Current flows through the dense magnetic induction coil 11 within the cavity of the composite filter 1, generating a magnetic induction zone. Within this zone, the magnetically conductive medium mesh 12 in the iron removal tank forms a omnidirectional magnetic space of up to 30,000 Gs. This omnidirectional magnetic space can adsorb 1μm to 3μm particulate iron impurities from the spray washing and alkaline solution in 360°. The specifications of the composite filter 1 are shown in Table 1.

[0141] Table 1 Operating Specifications of Composite Filters

[0142] temperature ℃ ≤90 Material / 304 Input voltage ACV 380 Maximum output current DCA 16 Filtration accuracy μm Magnetic particles with a diameter of ≥1 mm Iron powder concentration after filtration mg / L ≤300 Oil concentration after filtration mg / L ≤500

[0143] 2. Filtration of sprayed alkaline solution: The alkaline solution in the alkaline spray circulation tank 6 enters the horizontal scrubbing tank through the pipeline, and then is sprayed onto the surface of the strip steel to remove 80% of the residual iron powder and oil stains on the surface of the strip steel. The alkaline solution that has scrubbed the strip steel then enters the corresponding composite filter 1 through the circulation pipeline. After passing through the multi-layer magnetic medium mesh 12, the iron powder and oil stains in the alkaline solution are adsorbed on the medium mesh. The filtered sprayed alkaline solution will flow out from the discharge port and return to the alkaline solution circulation tank; this cycle is repeated.

[0144] 3. Electrolytic Alkali Solution Filtration: The alkali solution in the electrolytic circulation tank 7 enters the vertical electrolytic cell through pipelines. The remaining 20% ​​of iron powder and oil on the surface of the strip steel is removed by electrolytic cleaning. The cleaned electrolytic alkali solution enters the composite filter 1 through the circulation pipeline. After passing through multiple layers of magnetic medium mesh 12, the iron powder and oil in the alkali solution are adsorbed on the medium mesh. The filtered alkali solution will flow out from the discharge port and return to the electrolytic circulation tank 7.

[0145] 4. Power off: When the magnetic material is saturated, close the liquid inlet valve of composite filter 1 to stop the liquid inlet, then disconnect the current of composite filter 1 and open the slag discharge valve of composite filter 1 to drain the residual liquid in the cavity of composite filter 1 into the alkaline waste liquid recovery pipeline.

[0146] 5. Activate backwash mode: After the evacuation is completed, activate the backwash mode of the composite filter 1. Use the rinsing water in the hot rinsing circulation tank 2 to automatically rinse the residual impurities (high concentration of iron powder and oil stains, etc.) on the magnetic medium mesh 12 in the composite filter 1. The resulting rinsing wastewater is discharged to the buffer tank 41 through the drain port for storage.

[0147] 6. Turn off the backwash mode.

[0148] 7. Restart composite filter 1: Open the inlet valve and continue the operation from step 1 to step 6. These operation steps can be completed under fully automatic operation conditions.

[0149] The rinsing wastewater obtained in steps 4 and 5 will undergo further treatment:

[0150] (1) Solution preparation:

[0151] Cellulose is added to the mixing tank 31, followed by demineralized water, to ensure thorough mixing and the formation of a concentrated cellulose solution. The prepared concentrated cellulose solution is then transferred to a buffer tank 41 and thoroughly mixed with rinsing wastewater, or transferred to a pre-coating tank and mixed with demineralized water to obtain a pre-coating solution.

[0152] (2) Pre-coating:

[0153] The pre-coating liquid in the pre-coating tank enters the backwash filter 5 to pre-coat the cellulose onto the backwash filter cloth 51 and form a thin filter layer that can protect the backwash filter cloth 51.

[0154] (3) Mixing:

[0155] After pre-coating is completed, the entire system automatically enters the mixing mode. Then, the filter aid solution (cellulose concentrate) in the buffer tank 41 is thoroughly mixed with the backwash waste liquid to obtain a mixed waste liquid. The mixed waste liquid enters the backwash filter 5 and is filtered in batches through the backwash filter cloth 51. The filter layer formed on the surface of the backwash filter cloth 51 intercepts iron powder and oil in the mixed waste liquid, thereby creating a pressure difference during the batch filtration process of the backwash filter. When the pressure difference between the inlet and outlet of the backwash filter 5 reaches the set value or the filtration time of the backwash filter reaches the set value, the backwash filter 5 stops feeding liquid. The specifications of the backwash filter 5 used are shown in Table 2.

[0156] Table 2 Specifications of backwash filters

[0157] Filtration area <![CDATA[m 2 ]]> 12 Design operating temperature ℃ ≤90 Material / 304 Operating pressure bar ≤6 Concentration of clear liquid iron powder mg / L 0 Oil concentration in clear liquid mg / L 0

[0158] (4) Drain the clear fluid:

[0159] After the coating is completed, compressed air is used to drain the filter layer in the backwash filter 5, and then the clear liquid treated by the backwash filter 5 is discharged into the ditch and enters the subsequent energy medium.

[0160] (5) Drying the filter cake:

[0161] After the clear liquid is drained, the cavity of the backwash filter 5 is filled with compressed air to dry the backwash filter cloth 51 of the backwash filter 5, and to dry the filter residue on the backwash filter cloth 51, forming dry residue on the surface of the backwash filter cloth 51.

[0162] (6) Slag removal:

[0163] After the dry residue is formed, compressed air is used for backflushing to discharge the filter cake and dry residue sludge attached to the backwash filter cloth 51 into the sludge collection tank, and then transport them off-site for unified treatment.

[0164] Comparative Example 1

[0165] Comparative Example 1 and Example 3 will be compared. The difference between Comparative Example 1 and Example 3 is as follows:

[0166] The alkaline solution was treated using a traditional magnetic flux filter.

[0167] Relevant experimental and effect data:

[0168] The surface quality of the strip steel obtained in Example 3 and Comparative Example 1 were statistically analyzed respectively, and the macroscopic product comparison results are as follows: Figure 5 and Figure 6 As shown, the results of the microscopic product comparison are as follows: Figure 7 and Figure 8 As shown, this indicates that the surface of the product produced by the strip steel production system in Comparative Example 1 has coarse and loose crystals and uneven spots on the plate surface, while the surface of the product produced by the strip steel production system in Example 3 has no obvious defects and the plate surface has a uniform color.

[0169] The mass concentration of iron powder and the mass percentage of oil in the alkaline solutions obtained in Example 3 and Comparative Example 1 were statistically analyzed, and the results are shown in Table 3.

[0170] Table 3 shows the iron powder concentration and oil percentage in the alkaline solutions obtained in Example 3 and Comparative Example 1.

[0171]

[0172] Depend on Figure 4 , Figure 5 , Figure 6 and Figure 7 As shown in Table 3, the cleaning and purification system for high-grade automotive steel sheets provided in this application embodiment can further improve the surface quality of strip steel products on the basis of cleaning efficiency with high iron impurities and grease.

[0173] In addition, the present application provides a cleaning and purification system for high-grade surface automotive panels, which can be used in conjunction with a strip steel production system to obtain strip steel products with uniform color and no surface defects.

[0174] In summary, the cleaning and purification system for high-grade automotive steel panels provided in this application involves two steps: spray washing and electrolytic cleaning of the steel strip using two sets of composite filters 1. Then, the omnidirectional magnetic space generated by the magnetic induction coil 11 effectively adsorbs iron impurities and grease from the alkaline solution onto the magnetically conductive medium mesh 12, allowing for the recovery and reuse of the alkaline solution. The system then uses rinsing water from the hot rinsing circulation tank 2 to circulate and rinse the adsorbed iron impurities and grease from the surface of the magnetically conductive medium mesh 12, thus removing them. Additionally, a pre-coating solution is prepared using a cellulose solution preparation unit 3 and a buffer unit 4. This pre-coating solution is then used to pre-coat the backwash filter cloth 51 in the backwash filter 5. The buffer unit 4 holds the rinse water after rinsing, and the backwash filter cloth 51, which has undergone re-coating treatment, is used for batch filtration, effectively achieving simultaneous separation of iron impurities and grease. This improves the cleaning efficiency of iron impurities and grease during the degreasing process.

[0175] In addition, the present application provides a cleaning and purification system for high-grade automotive panels, which can achieve "simultaneous iron and oil removal" filtration on the steel strip surface. Furthermore, by using only physical filtration, the effective components of the alkaline solution used in spray washing and electrolytic cleaning are not destroyed. Therefore, it has a high degree of intelligence and can achieve unattended operation and remote monitoring.

[0176] In addition, the present application provides a cleaning and purification system for high-grade automotive panels. The overall system can operate stably and has a low failure rate. Furthermore, since the alkaline solution is recycled, the discharge of concentrated alkaline wastewater can be avoided, thereby reducing the treatment cost of the alkaline solution.

[0177] In addition, this application provides a cleaning and purification system for high-grade automotive panels. Using a composite filter 1, the alkaline solution can be circulated and adsorbed through the omnidirectional magnetic space generated by the magnetic induction coil 11 and the magnetic medium mesh 12, thereby improving the cleanliness of the alkaline solution during the recycling process and avoiding surface defects caused by excessive impurities in the alkaline solution. Therefore, it can be used in conjunction with a strip steel production system to produce high-grade automotive panels.

[0178] In addition, the present application provides a cleaning and purification system for high-grade automotive panels, which uses a backwash filter 5. During the normal operation of the cleaning and purification system, the magnetic medium mesh 12 in the composite filter 1 only needs to be backwashed every 3 months to remove impurities from the magnetic medium mesh 12. The overall system is time-saving, simple to operate, and easy to maintain. Furthermore, the filter element of the backwash filter 5 can be used for a lifetime, while the backwash filter cloth 51 can be replaced every 9 to 12 months, resulting in low overall maintenance costs.

[0179] The above description is merely a specific embodiment of this application, enabling those skilled in the art to understand or implement this application. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the general principles defined herein may be implemented in other embodiments without departing from the spirit or scope of this application. Therefore, this application is not to be limited to the embodiments shown herein, but is to be accorded the widest scope consistent with the principles and novel features claimed in this application.

Claims

1. A cleaning and purification system for high-grade automotive panels, characterized in that, The system includes: The composite filtration unit includes a hot rinsing circulation tank (2), an alkaline spray circulation tank (6), an electrolysis circulation tank (7), and at least two sets of composite filters (1). Each composite filter (1) is equipped with a magnetic induction coil (11) and a magnetically conductive medium mesh (12). The magnetic induction coil (11) is located around the magnetically conductive medium mesh (12) to form a omnidirectional magnetic space. The outlet of the hot rinsing circulation tank (2) is connected to the inlet of the composite filter (1) to rinse the impurities in the magnetically conductive medium mesh (12). The outlet and inlet of the alkaline spray circulation tank (6) are respectively connected to one set of the composite filters (1). The outlet and inlet of the electrolysis circulation tank (7) are respectively connected to another set of the composite filters (1). The backwashing unit includes a cellulose solution preparation unit (3), a buffer unit (4), and a backwash filter (5). The outlet of the cellulose solution preparation unit (3) is connected to the inlet of the backwash filter (5). The buffer unit (4) includes at least two buffer tanks (41). The inlet of the buffer tank (41) is connected to the outlet of the composite filter (1), and the outlet of the buffer tank (41) is connected to the inlet of the backwash filter (5). The cellulose solution preparation unit (3) includes a solution preparation tank (31) and a cellulose pre-coating tank (32). The outlet of the solution preparation tank (31) is connected to the inlet of the cellulose pre-coating tank (32), and the inlet of the cellulose pre-coating tank (32) is connected to the inlet of the backwash filter (5). The outlet of the solution preparation tank (31) is also connected to the inlet of the buffer tank (41). The backwash filter (5) is equipped with a backwash filter cloth (51); In the cellulose solution preparation unit (3), the weights m1 and m2 of cellulose concentrate in the cellulose concentrate satisfy the relationship: m1:m2 = 0.1:1 to 0.3:1; the weights m2 and m3 of the cellulose concentrate in the pre-coating solution satisfy the relationship: m2:m3 = 0.03:1 to 0.08:1; the coating amount of the pre-coating solution on the pre-treated backwash filter cloth (51) is 1.0 kg / m. 2 ~1.5kg / m 2 .

2. A cleaning and purification method for high-grade automotive panels, characterized in that, The cleaning and purification method is adapted to the cleaning and purification system of claim 1, and the cleaning and purification method includes: The strip steel is sprayed and washed with alkaline solution to obtain the first waste liquid and the primary strip steel. The primary strip steel is electrolytically cleaned using an alkaline solution to obtain a second waste liquid and a strip steel product, respectively. Under the condition of a preset magnetic field strength, the first waste liquid and the second waste liquid are circulated and filtered by a magnetic medium mesh (12) to adsorb the oil and iron powder of the first waste liquid and the second waste liquid, respectively, and the first impurity medium mesh, the second impurity medium mesh and the circulating alkaline solution are obtained respectively. The first impurity media screen and the second impurity media screen are backwashed with rinsing water to remove oil and iron powder from the first impurity media screen and the second impurity media screen, and backwash waste liquid is obtained. The backwash waste liquid and the filter aid solution are mixed to obtain a mixed waste liquid; The backwash filter cloth (51) is pre-coated to obtain a pretreated backwash filter cloth (51); The mixed waste liquid is batch filtered using the pretreated backwash filter cloth (51) to obtain filtrate and filter residue respectively; The filtrate and the filter residue are respectively post-treated to obtain effluent and sludge.

3. The method according to claim 2, characterized in that, The preset magnetic field strength is ≥3000Gs, and the target particle size of the adsorption filtration is ≥1μm.

4. The method according to claim 2, characterized in that, The conductivity of the rinsing water is ≤50S / m, and the temperature of the rinsing water is 45℃~80℃.

5. The method according to claim 2, characterized in that, The temperature of the batch filtration is ≤90℃, and the pressure of the batch filtration is ≤6 bar.

6. The method according to claim 2, characterized in that, The process of pre-coating the backwash filter cloth to obtain a pretreated backwash filter cloth includes the following steps: The cellulose and demineralized water are mixed to obtain a concentrated cellulose solution; The cellulose concentrate is mixed with the demineralized water to obtain a pre-coating solution; The backwash filter cloth (51) is pre-coated with the pre-coating liquid so that the cellulose in the pre-coating liquid adheres to the backwash filter cloth (51) to obtain a pre-treated backwash filter cloth (51).

7. The method according to claim 2, characterized in that, The step of post-processing the filtrate and the filter residue to obtain effluent and sludge includes the following steps: The filtrate is compressed and discharged to obtain a clear liquid; The filter residue is backflushed to obtain sludge; The compressed air venting and the backflushing both use compressed air as the medium, and the pressure of the compressed air is 4 kPa to 7 kPa.

Images