Peeling treatment method for coated aluminum material, treatment device, treatment device control unit, and program

Abstract

To efficiently recover an aluminum material from a resin-coated aluminum material in high yield.SOLUTION: To recover an aluminum material with good yield and to regenerate a sulfuric acid solution by bringing the sulfuric acid solution into contact with a coating material coated on the aluminum material to dissolve the coating material in the sulfuric acid solution, separating and removing the coating material from the aluminum material, and decomposing the coating material dissolved in the sulfuric acid solution with the electrolytic sulfuric acid solution.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for stripping a coated aluminum material, a processing device, a processing device control unit, and a program for stripping and removing a coating material from an aluminum material coated with the coating material. [Background technology]

[0002] Copper wire is widely used in automobiles, home appliances, industrial applications, etc. However, copper reserves are estimated to last for around 40 years, and with the rapid spread of electric vehicles in particular, this is expected to become even shorter, raising concerns about copper depletion. Electric vehicles generally require about four times as much copper as gasoline-powered vehicles because they require electric motors and batteries. Furthermore, copper mines have seen a gradual decline in the quality of copper concentrate in recent years, putting an increasing strain on the mining and smelting processes. However, the construction and expansion of copper mines has not progressed enough to meet demand, and there are fears that copper supplies will not be able to keep up. Furthermore, it is said that it takes about 15 years from approval to construction of a new copper mine, and even if approval and construction could be expedited, it is unlikely to be enough to make up for the copper supply shortage. Therefore, there are concerns that a shortage of batteries will occur in the future due to a shortage of copper, and although battery recycling is being considered, it has been pointed out that the cost is very high and that there will not be enough to supply the necessary amount of copper.

[0003] Substituting a material more abundant than copper is thought to be an effective solution, and aluminum conductor wires are being considered. Aluminum is the most abundant metal in the Earth's crust, said to be about 1,000 times more abundant than copper. For example, aluminum conductor wires are already used in high-voltage power transmission lines. Although aluminum has half the electrical conductivity of copper, it is one-fifth the price and one-third the specific gravity. As a conductor wire material is expected to shift from copper to aluminum in the future, aluminum recovery technology is needed for aluminum wires, just as it is for copper wires used for windings.

[0004] Since the method for recovering aluminum wire has not been disclosed, we will show the method for recovering copper wire, which is used as a conductive material in the same way as aluminum wire. Copper wires are often coated with insulating resins, and copper recovery requires the coating material to be stripped from the wire. Currently, the coating material is stripped from some copper wires for windings using a dry method. One dry method involves making cuts with a rotating blade, then crushing the wire with opposing rolling rollers, and separating the wires based on the difference in specific gravity (Patent Document 1). As another treatment method, Patent Document 2 discloses a recovery method in which a resin-coated copper wire is heat-treated at 250° C. to 380° C. in an air atmosphere, and the thermally denatured insulating coating is mechanically peeled off.

[0005] As for wet recycling methods, Patent Document 3 discloses a recovery method in which the material is heated at 500°C to 800°C using superheated steam, and then washed with 10 to 35 mass% hydrochloric acid to remove the material, while Patent Document 4 discloses a recovery method in which the material is chemically stripped using a stripping solution containing an inorganic alkali, an alkanolamine having 1 to 10 carbon atoms, and water. [Prior art documents] [Patent documents]

[0006] [Patent Document 1] Patent No. 5828145 specification [Patent Document 2] Patent No. 6604515 specification [Patent Document 3] Patent No. 6056088 Specification [Patent Document 4] Patent Publication No. 2021-108531 Summary of the Invention [Problem to be solved by the invention]

[0007] However, in Patent Documents 1 and 2, the peeling rate of the coating material is low at around 97% due to contamination with insulating coating components, and recycling requires processing starting from the smelting process. In Patent Document 3, superheated steam is used to heat the wire to 500°C to 800°C, followed by chemical stripping using hydrochloric acid. These conventional techniques require high heat treatment temperatures and mechanical or chemical removal after heating, resulting in an increased number of treatment steps, which increases equipment and processing costs. Furthermore, high-temperature heat treatment can cause problems such as oxide formation on the copper wire, which reduces purity. This technique cannot be applied to aluminum due to the high processing temperature. Furthermore, Patent Document 4 raises concerns about the cleanliness of the copper wire after stripping, and makes no mention of the state of the solution after stripping, raising concerns about the insulating film removal ability of the stripping / removal solution as the number of uses increases.

[0008] When recovering high-purity copper wire, further issues include the cleanliness of the copper wire after stripping and the yield of the copper wire during stripping. Furthermore, in the recovery process, it is an issue in this field to completely remove the insulating film while reducing energy costs and carbon dioxide emissions. Chemical removal methods are effective as a way to solve these issues, but there is also the issue that the number of times the solution can be used is limited because the used solution contains dissolved insulating film components and its stripping and removal ability decreases with increasing use. Furthermore, in disposing of used stripping / removal solutions, the following problems can easily be imagined as the number of stripping / removal treatments increases. (1) Increased costs for waste liquid treatment and replacement, and collection and transportation costs (2) Increased wastewater treatment costs due to multiple wastewater treatment processes (3) Increased environmental impact from waste liquid treatment to replacement and regeneration

[0009] In the case of aluminum materials, there is a need to efficiently recover the aluminum material from materials coated with a coating material, and similar issues exist.

[0010] The present invention has been made in consideration of the above-mentioned conventional problems, and aims to provide a recovery method, etc., which can recover aluminum material from coated aluminum material with a high yield by chemical treatment alone, similar to copper wire, and which can autodecompose the coating material components dissolved in the used solution. [Means for solving the problem]

[0011] That is, in the first form of the method for stripping a coated aluminum material, a sulfuric acid solution is brought into contact with a coating material that has coated an aluminum material, and the coating material is dissolved in the sulfuric acid solution to be stripped and removed from the aluminum material, and the coating material dissolved in the sulfuric acid solution is decomposed in an electrolytic sulfuric acid solution containing persulfuric acid.

[0012] In another embodiment of the method for stripping a coated aluminum material, in the above-described embodiment, the concentration of persulfuric acid in the electrolytic sulfuric acid solution is 0.5 g / L or more.

[0013] In another embodiment of the method for stripping a coated aluminum material, in the above-described embodiment, the sulfuric acid solution used to decompose the coating material is reused for stripping and removing the coated aluminum material or other coated aluminum materials.

[0014] Another embodiment of the invention of the stripping treatment method for coated aluminum material is the invention of the above embodiment, in which the sulfuric acid solution brought into contact with the coating material coating the aluminum material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 94.0 mass% or more, and a temperature within the range of 60 to 140°C.

[0015] Another aspect of the invention of the method for stripping a coated aluminum material is the invention of the above aspect, wherein the sulfuric acid solution brought into contact with the coating material coating the aluminum material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more during part or all of the stripping and removal process, and the sulfuric acid concentration is 94.0 mass% or more and the temperature is within the range of 60 to 140°C.

[0016] Another embodiment of the invention of the method for stripping a coated aluminum material is the invention of the above embodiment, in which the sulfuric acid solution brought into contact with the coating material coating the aluminum material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 90.0 mass% or more but less than 94.0 mass%, and a temperature within the range of 60 to 140°C.

[0017] Another aspect of the invention of the method for stripping a coated aluminum material is the invention of the above aspect, wherein the sulfuric acid solution brought into contact with the coating material coated on the aluminum material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more during part or all of the stripping and removal process, and the sulfuric acid concentration is 90.0 mass% or more but less than 94.0 mass%, and the temperature is within the range of 60 to 140°C.

[0018] Another embodiment of the invention of the method for stripping a coated aluminum material is the invention of the above embodiment, in which the electrolytic sulfuric acid solution is electrolyzed at a solution temperature of 20 to 60°C.

[0019] In another embodiment of the method for stripping a coated aluminum material, in the above-described embodiment, the decomposition state of the coating material is determined by one or both of the electrical conductivity and the oxidation-reduction potential of the sulfuric acid solution.

[0020] In another embodiment of the method for stripping coated aluminum material, when the decomposition state of the coating material reaches a standard, it is determined that regeneration is complete, and the regenerated sulfuric acid solution is used to strip and remove the coated copper material.

[0021] A first embodiment of the invention of a coating aluminum material peeling and removal treatment device has a sulfuric acid solution contact section that brings a sulfuric acid solution into contact with the coating material of the coated aluminum material, and a decomposition section that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution.

[0022] In another form of the invention of the coated aluminum material peeling and removal treatment device, in the above-mentioned form of the invention, the sulfuric acid solution contact section has one or both of an immersion treatment tank in which the coated aluminum material is immersed in the sulfuric acid solution and a release contact tank in which the sulfuric acid solution is released onto the coated material and brought into contact with it.

[0023] In another embodiment of the present invention, in the above-described embodiment of the coating aluminum material peeling and removal treatment device, the decomposition section is provided with an electrolysis section that electrolyzes a sulfuric acid solution.

[0024] Another embodiment of the invention of the coated aluminum material peeling and removal treatment device is the same as the above embodiment, in which the device comprises a plurality of the sulfuric acid solution contact sections, and one or more of the electrolysis sections are capable of selectively electrolyzing the sulfuric acid solutions of the plurality of sulfuric acid solution contact sections.

[0025] Another form of the invention of the coated aluminum material peeling and removal treatment device is the same as the above-mentioned form of the invention, in which the decomposition section is provided with a decomposition storage tank and an electrolysis section, and an electrolysis circulation path is provided between the decomposition storage tank and the electrolysis section for circulating sulfuric acid solution.

[0026] Another embodiment of the present invention of the coated aluminum material peeling and removal treatment device is the same as the above embodiment, and further includes a decomposition / regeneration liquid transfer path between the sulfuric acid solution contact section and the decomposition storage tank.

[0027] Another aspect of the present invention of the coated aluminum material peeling and removal treatment device is the above-mentioned aspect of the present invention, further comprising: a measuring unit that measures the decomposition state of the sulfuric acid solution in the decomposition unit; a control unit that controls electrolysis in the electrolysis unit, and liquid transfer through the electrolysis circulation path and the decomposition / regeneration liquid transfer path; The control unit receives the measurement result from the measurement unit and determines the content of the control based on the measurement result.

[0028] The invention of the stripping device control unit is provided in a treatment device having a measuring unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, a sulfuric acid solution contact unit that dissolves the coating material of the coated aluminum material by contacting it with the sulfuric acid solution to strip and remove it, a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, a decomposition / regeneration liquid transfer path provided between the sulfuric acid solution contact unit and the decomposition storage tank, an electrolysis unit that electrolyzes the sulfuric acid solution, and an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, receiving the measurement results from the measurement unit, and controlling the electrolysis in the electrolysis unit and the liquid transfer in the electrolysis circulation path and the decomposition / regeneration liquid transfer path; Upon receiving the measurement results, control is performed to determine the content of the control based on the measurement results.

[0029] The program invention is a program executed by a control unit that receives measurement results from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls: a sulfuric acid solution contact unit that dissolves the coating material of the coated aluminum material by contacting it with the sulfuric acid solution to peel and remove it; and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution; liquid delivery through a decomposition / regeneration liquid delivery path provided between the sulfuric acid solution contact unit and the decomposition storage tank; electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution; and liquid delivery through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit. The program includes a step of sending the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact portion to a decomposition storage tank through a decomposition / regeneration liquid sending path; receiving the measurement results; Executing electrolysis by the electrolysis unit and sending solution through the electrolysis circulation path until the measurement result reaches a standard; When the measurement result reaches a reference value, electrolysis by the electrolysis unit is stopped, and the sulfuric acid solution in the decomposition storage tank is sent to the sulfuric acid solution contact unit through the decomposition / regeneration liquid sending path; The control unit executes the process. [Effects of the Invention]

[0030] According to the present invention, the coating material of a coated aluminum material is brought into contact with a sulfuric acid solution, whereby the coating material is peeled off and removed from the aluminum material, and the aluminum material can be recovered. The dissolved coating material is decomposed in an electrolytic sulfuric acid solution containing persulfuric acid. [Brief explanation of the drawings]

[0031] [Figure 1] FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used in an embodiment of the present invention. [Figure 2] 1 is a process flow diagram illustrating an embodiment of a method for stripping and removing a coating material and a method for regenerating a stripping solution according to the present invention. [Figure 3] FIG. 10 is a schematic cross-sectional view showing an example of an apparatus used in another embodiment. [Figure 4] 10 is a flowchart showing the procedure of an electrolysis and regeneration step in another embodiment. [Figure 5] FIG. 10 is a flow chart illustrating an embodiment in which an electrolytic sulfuric acid solution is used as the solution that is brought into contact with the coating material to strip and remove it. [Figure 6] FIG. 10 is a schematic cross-sectional view showing an example of an apparatus used in another embodiment of the present invention. [Figure 7] This is a processing flow when multiple stripping tanks are prepared. [Figure 8] FIG. 10 is a schematic cross-sectional view showing an example of an apparatus used in yet another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0032] (Embodiment 1) FIG. 1 is a schematic cross-sectional view showing an example of an apparatus used in one embodiment of the present invention, and shows a treatment apparatus applicable to a method for stripping a resin coating material coated on an aluminum material and a method for regenerating a sulfuric acid solution after the stripping.

[0033] The aluminum material is preferably an aluminum alloy containing 0.1 to 2.8 mass% iron and 0.002 to 2 mass% neodymium, but the present invention is not limited to a specific composition of the aluminum material and may be pure aluminum. The shape of the aluminum material is exemplified by wire and plate shapes, but is not limited to a specific shape.

[0034] The coating material may be a coating film having a small thickness relative to the surface area of ​​the aluminum material, and is preferably used for those having insulation and heat resistance. Examples of insulating properties include those having a high volume electrical resistivity (10 7 The heat resistance required varies depending on the application, but in the preferred application of the present invention, heat resistance class B (130°C) specified in JIS standard C4003 can be mentioned.

[0035] The coating material may be either a natural resin or a synthetic resin, and may be either a thermoplastic resin or a thermosetting resin, and is not limited to a specific resin. The coating material may be, for example, any of polyimide resin, polyesterimide resin, polyamideimide resin, polyurethane resin, and polyester resin. The coating material is not limited to one type, and may be a combination of multiple types, for example, layers of different materials.

[0036] The coating material may cover the entire aluminum material, or may cover only a portion of the aluminum material (in the cross-sectional or longitudinal direction). Examples of the coating material include those formed in the form of a film on the surface of the aluminum material, but the thickness is not limited. In the following embodiment, an aluminum wire is used as the aluminum material.

[0037] The treatment device 1 has a treatment tank 5 that contains a sulfuric acid solution, and the treatment tank 5 immerses the resin-coated aluminum wire 2 in the sulfuric acid solution to remove the coating material.

[0038] The treatment device 1 also has an electrolytic sulfuric acid device 6 that electrolyzes a sulfuric acid solution to decompose the stripping material. The treatment tank 5 is one form of the sulfuric acid contact section of the present invention, and corresponds to an immersion contact tank. The electrolytic treatment device 6 constitutes a part of the decomposition section of the present invention, and corresponds to the electrolysis section. In this embodiment, the treatment tank 5 also serves as a decomposition storage tank in the decomposition section.

[0039] In the treatment tank 5, stirring means such as an external air pump 4 and an air bubble generator 3 connected thereto may be provided to stir the inside of the tank as needed. An electrolytic sulfuric acid device 6 for regenerating the sulfuric acid solution is connected to the treatment tank 5. A solution inlet path 9A and one end of a solution outlet path 9B are connected to the treatment tank 5, allowing the solution to be introduced into the treatment tank 5 and discharged from the treatment tank 5. The inlet path 9A and the outlet path 9B form an electrolytic circulation path.

[0040] The other ends of the solution inlet path 9A and the outlet path 9B are connected to the liquid passage of the electrolytic cell 10, and a circulation pump 8 is provided in the solution outlet path 9B. By operating the circulation pump 8 to send the solution to the electrolytic cell side, the solution is sent to the outlet path 9B, the electrolytic cell 10, the inlet path 9A, and the treatment tank 5, enabling the solution to circulate.

[0041] In the electrolytic cell 10, a solution outlet path 9B is connected to the lower end of the cell, and a solution inlet path 9A is connected to the upper end of the cell. An anode 10A and a cathode 10B are installed in the flow path between them, and a bipolar electrode 10C is installed between the anode 10A and the cathode 10B, so that the solution moves from bottom to top in the flow path between the electrodes. A DC power supply 7 for electrolysis is installed between the anode 10A and the cathode 10B.

[0042] In this embodiment, the device having bipolar electrodes has been described, but the presence or absence of bipolar electrodes is not particularly limited in this embodiment.

[0043] In this embodiment, the device shown in FIG. 1 is used, but the electrolysis method is not particularly limited, and is not limited to the device shown in FIG.

[0044] In addition, when electrolytic sulfuric acid is not used to strip the coating material, the stripping process can be performed without introducing electrolytic sulfuric acid into the treatment tank. In this case, in the device shown in Figure 1, electrolytic sulfuric acid is not introduced into the treatment tank through the inlet line 9A and the outlet line 9B during the stripping process, and electrolytic sulfuric acid can be introduced into the treatment device through the inlet line 9A and the outlet line 9B after the stripping process.

[0045] <Flowchart> FIG. 2 is a flowchart showing the steps of the resin peeling and removal method and the sulfuric acid solution decomposition and regeneration method of the present invention, which will be described below. Furthermore, the steps in the flowchart are the same whether the sulfuric acid concentration is 94.0 mass% or more or 90.0 mass% or more but less than 94.0 mass%, so here we will explain the case where the sulfuric acid concentration is 94.0 mass% or more as an example.

[0046] The method mainly includes a first step of a stripping process in which the coating material is stripped and removed from the surface of the aluminum wire 2 using a sulfuric acid solution, which is an acidic stripping solution, and a second step of a stripping solution regeneration process in which the sulfuric acid solution is electrolyzed to produce peroxodisulfuric acid and peroxomonosulfuric acid, which are generated by self-decomposition of the peroxodisulfuric acid, and other oxidizing agents, which are components of the coating material, react with each other, thereby decomposing the organic matter into carbon dioxide and water.

[0047] In the first stripping step (step S1), a sulfuric acid solution is placed in a treatment tank 5. The sulfuric acid solution is preferably adjusted to a sulfuric acid concentration of 94.0 mass % or more and a temperature within a range of 60 to 140°C. It is even more preferable to set the lower limit at 90°C and the upper limit at 100°C. The temperature of the sulfuric acid solution can be adjusted by heating it using a heater (not shown) installed in the tank. The aluminum wire 2 on which a coating material (not shown) is formed is immersed in this sulfuric acid solution to bring the resin coating material into contact with the sulfuric acid solution.

[0048] In addition, if the sulfuric acid concentration of the sulfuric acid solution is increased, the degree of dissociation of sulfuric acid decreases, resulting in a lower ion concentration in the solution. In other words, the solution becomes hydrophobic, making it possible to dissolve the coating material covering the aluminum wire.

[0049] Furthermore, increasing the temperature of the sulfuric acid solution increases the dissolution rate. For this reason, the sulfuric acid solution and electrolytic sulfuric acid solution that come into contact with the insulating coating of the coating material should preferably be at a temperature of 60°C or higher. For the same reason, it is also preferable to set it at 90°C or higher. On the other hand, if the solution temperature is too high, it will cause the aluminum wire to dissolve, resulting in a decrease in recovery yield. For this reason, it is preferable to set the solution temperature at 140°C or lower. Furthermore, for the same reason, it is also preferable to set it at 100°C or lower. That is, by setting the lower limit concentration of the sulfuric acid solution to 94.0 mass % and the solution temperature within the above range, it is possible to recover the aluminum material with a high yield without dissolving it much, although the treatment time tends to be longer. On the other hand, when the sulfuric acid concentration is 90.0 mass % or more but less than 94.0 mass %, the treatment time is short, but the aluminum material recovery rate is slightly reduced. The sulfuric acid concentration can be selected according to the total treatment cost and production volume. If the sulfuric acid concentration is less than 90.0 mass %, the yield recovery rate of the aluminum material will drop drastically, and the total processing cost will not be worth the recoverable aluminum material, so it is desirable that the sulfuric acid concentration be 90.0 mass % or more.

[0050] Here, the sulfuric acid solution may be sulfuric acid itself or a sulfate, etc., as long as it can provide the above-mentioned sulfuric acid concentration. As for the solution for peeling and removing the coating material, a sulfuric acid solution containing persulfuric acid can be used as described below, but in the form of this flowchart, the action of persulfuric acid is not required, so a persulfuric acid-free solution or one with a persulfuric acid concentration of less than 0.5 g / L is used.

[0051] When the aluminum wire 2 coated with the coating material is immersed, air can be sent from an external air pump 4 to the air bubble generator 3 to appropriately agitate the sulfuric acid solution. In the aluminum wire 2 coated with a coating material, the coating material is gradually peeled off and removed by contact with the sulfuric acid solution, and the coating material dissolves in the sulfuric acid solution.

[0052] Once the coating material has been removed from the aluminum wire 2, the aluminum wire 2 is subjected to a cleaning and drying step (step S2). In the cleaning and drying step (step S2), the aluminum wire 2 from which the coating material has been peeled off is taken out of the treatment tank 5, washed with a cleaning solution (not shown), and dried. The cleaned and dried aluminum wire 2 can be recycled with a high recovery rate. For example, a recovery rate of 90% or more can be obtained for the aluminum wire. In recycling, for example, a process of melting and refining the collected aluminum wire to produce an aluminum wire can be adopted.

[0053] The sulfuric acid solution in which the coating material is dissolved is subjected to electrolysis by the electrolytic sulfuric acid device 6 in the electrolytic sulfuric acid solution generating step (step S3). In the electrolytic sulfuric acid solution generation process, the circulation pump 8 is operated to circulate the sulfuric acid solution in the treatment tank 5 through the delivery line 9B, the electrolytic cell 10, the introduction line 9A, and the treatment tank 5. In the delivery line 9B, a cooler (not shown) or the like is provided to adjust the temperature of the sulfuric acid solution being delivered to a temperature of 20 to 60°C, which is a desirable electrolysis condition.

[0054] If the solution temperature during electrolysis is below 20°C, the diffusion rate of ions to the anode surface will be slow, and increasing the current density will cause wear on the diamond used in the electrode. On the other hand, if the temperature during electrolysis is above 60°C, adverse effects such as the self-decomposition rate of the oxidant will increase and the oxidant will be reduced at the cathode will occur. Therefore, it is desirable to keep the temperature range between 20 and 60°C.

[0055] In the electrolysis cell 10, a voltage is applied between the anode 10A and the cathode 10B by the electrolysis DC power supply 7, causing a current to flow, and the sulfuric acid solution flowing through the flow path is electrolyzed by the anode 10A, the cathode 10B, and the bipolar electrode 10C, thereby producing an electrolytic sulfuric acid solution such as peroxodisulfuric acid. The produced electrolytic sulfuric acid solution can be supplied to the treatment tank 5 via the introduction line 9A, and can proceed to the sulfuric acid solution regeneration step (step S4). In the sulfuric acid solution regeneration process, it is desirable to increase the oxidizing power of the electrolytic sulfuric acid solution supplied to the treatment tank 5 by heating it to 60 to 140°C using a heater (not shown) installed in the inlet 9A or a heater installed in the treatment tank 5. If the temperature is lower than 60°C, the self-decomposition rate of the oxidizing agent is slow, and if the temperature exceeds 140°C, the self-decomposition rate is too fast.

[0056] In the treatment tank 5 where the electrolytic sulfuric acid solution is introduced, peroxodisulfuric acid (SO2) 2- ) and peroxomonosulfuric acid (HSO5 - The organic matter, which is a component of the coating material dissolved in the sulfuric acid solution, reacts with sulfuric acid (SO2) and hydrogen peroxide (H2O2), breaking it down into carbon dioxide and water, regenerating the sulfuric acid solution. The regenerated sulfuric acid solution can then be used again to strip and remove the coating material from another aluminum wire with a resin coating. In addition, when decomposing coating materials, a persulfuric acid concentration of 0.5 g / L or higher is desirable. If the concentration is less than 0.5 g / L, the decomposition efficiency of the coating material is insufficient. On the other hand, since the released persulfuric acid reacts immediately with organic matter, the persulfuric acid concentration can only rise to about 5.0 g / L. To exceed 5.0 g / L would require a large number of electrolytic cells, which is not practical from a cost perspective.

[0057] The present invention will now be explained chemically. The process in which the coating material dissolves in the electrolyzed sulfuric acid solution is a physical phenomenon in which a hydrophobic insulating film dissolves and diffuses in the hydrophobic sulfuric acid solution, and no chemical reaction formula exists. The chemical reaction formula when sulfuric acid solution is electrolyzed is shown below. From equation (1), when sulfuric acid solution is electrolyzed, hydrogen sulfate ions (HSO4 - ) reacts with peroxodisulfate (SO8 2- ) is produced. Also, since peroxodisulfate is unstable, peroxomonosulfate (HSO5 -) and hydrogen peroxide (H2O2) (Equations (2) and (3)), and there are three types of oxidizing agents in the electrolytic sulfuric acid solution. 2HSO - → 2H + + S2O8 2- + 2e - (1) S2O8 2- + H2O → HSO5 - + HSO4 - (2) HSO5 - + H2O → HSO4 - + H2O2(3) Next, the reaction in which the insulating film, which is an organic material, reacts with an oxidizing agent such as peroxodisulfuric acid to decompose into carbon dioxide and water will be described.

[0058] By generating an electrolytic sulfuric acid solution, the resin is decomposed into sulfate radicals and hydroxyl radicals as shown in formulas (4) and (5). The generated sulfate radicals and hydroxyl radicals completely oxidize and decompose the resin components in the stripping / removal solution as shown in formulas (6) and (7). S2O8 2- → 2SO4 - (4) 2SO4 - + 2H2O → 2HSO4 - + 2OH· (5) C, H + 2SO4 - · → 2HSO4 - + xCO2+ yH2O (6) C, H + 2OH· → xCO2+ yH2O (7)

[0059] [Slower decomposition rate of coating materials] The decomposition rate of the insulating coating material decreases as the resin concentration in the sulfuric acid solution or electrolytic sulfuric acid solution increases, and also decreases as the oxidizing agent concentration decreases. When the organic coating material dissolves, the electrical conductivity decreases as the concentration of the insulator organic material increases. Therefore, the organic material concentration can be estimated from the electrical conductivity, and the decomposition rate can be determined. There are methods for directly analyzing the organic material concentration, but incorporating such a method into a device would be too expensive, so this method provides a simpler method for determining the concentration. The oxidizing agent reacts with organic matter, decomposing it into carbon dioxide and water. Therefore, the balance between the oxidizing agent generation rate and the organic matter dissolution rate is important. If the oxidizing agent generation rate is slower than the organic matter dissolution rate, the organic matter concentration in the sulfuric acid solution or electrolytic sulfuric acid solution will gradually increase, and eventually the organic matter will no longer dissolve. By measuring the oxidation-reduction potential of the solution, the amount (concentration) of the oxidizing agent can be determined, and the decomposition rate of the coating material can be determined. Therefore, a measurement unit that measures the decomposition state of the sulfuric acid solution is preferably one that measures either the electrical conductivity or the oxidation-reduction potential of the sulfuric acid solution, or both.

[0060] (Embodiment 2) 3 shows an example of a treatment apparatus 1A in which a measurement unit 11 for measuring electrical conductivity or redox potential is provided in a treatment tank 5. Electrical conductivity can be measured with a conductivity meter, and redox potential can be measured with a redox potentiometer. Note that components similar to those described above are designated by the same reference numerals, and their description will be omitted. As the decomposition progresses, the electrical conductivity increases, and when it reaches a predetermined reference value, it can be determined that the decomposition has ended. The oxidation-reduction potential increases as the decomposition progresses, and when it reaches a predetermined reference value, it can be determined that the decomposition has ended.

[0061] The measurement results of the measurement unit 11 are received by the control unit 20 and can be used to control the electrolytic cell 10 and the circulation pump 8. The operation of the electrolytic cell 10 and the circulation pump 8 continues until the measurement results of the measurement unit 11 reach a predetermined standard, and when the measurement results reach the standard, the regeneration is considered to be complete and the operation of the electrolytic cell 10 and the circulation pump 8 can be stopped. At that time, a notification can be given via a display unit or the like, and depending on the device configuration, the sulfuric acid solution in the treatment tank 5 may be moved, for example. In this embodiment, the measuring unit 11 is described as measuring the electrical conductivity or oxidation-reduction potential of the sulfuric acid solution, but the present disclosure is not limited to this, and the configuration is not particularly limited as long as it can measure the decomposition state of the coating material in the sulfuric acid solution.

[0062] FIG. 4 is a flowchart showing the electrolytic sulfuric acid solution production process and regeneration process. Electrolysis is initiated based on the electrolytic sulfuric acid solution generation process, and the process proceeds to the regeneration process (steps s3 and s4). Next, measurement is performed by the measuring device 11 (step s5), and the measurement result is received by the control unit 20. The control unit 20 compares the measured value with a predetermined reference value stored in the memory unit and determines whether the measured value has reached the reference value (step s6). If the measured value has not reached the reference value (step s6, No), electrolysis and regeneration are continued (go to step s3). If the measured value has reached the reference value (step s6, Yes), regeneration is considered to be complete, and electrolysis and operation of the circulation pump are stopped. Thereafter, the sulfuric acid solution can be reused as needed.

[0063] (Embodiment 3) Next, a third embodiment in which the coating material coated on the aluminum wire 2 is peeled off and removed with a sulfuric acid solution containing persulfuric acid using the treatment device 1 will be described with reference to the flowchart of FIG.

[0064] First, the electrolytic sulfuric acid solution generating step (step S10) is carried out. A sulfuric acid solution is contained in the treatment tank 5. In this case, the sulfuric acid solution preferably has a sulfuric acid concentration of 90.0 mass % or more. The difference between the sulfuric acid solution in Embodiment 1 and the electrolytic sulfuric acid solution in Embodiment 2 is the presence or absence of a strong oxidizing agent. When a strong oxidizing agent is present, the dissolution rate increases due to its oxidizing power. Therefore, when peeling and removing a coating material using a sulfuric acid solution containing persulfuric acid, it is desirable to set the lower limit of the sulfuric acid concentration to 90.0 mass% or more. For example, when the sulfuric acid concentration is 90.0% by mass or more and less than 94.0% by mass, the use of electrolytic sulfuric acid can shorten the treatment time compared to when electrolytic sulfuric acid is not used. As with sulfuric acid solutions, increasing the solution temperature increases the dissolution rate, so it is desirable to keep the temperature of the electrolytic sulfuric acid solution at 60°C or higher. For the same reason, a temperature of 90°C or higher is also desirable.

[0065] In the electrolytic sulfuric acid solution generating process, the circulation pump 8 is operated to circulate the sulfuric acid solution in the treatment tank 5 through the delivery line 9B, the electrolytic cell 10, the introduction line 9A, and the treatment tank 5. In the delivery line 9B, a cooler (not shown) or the like is provided to adjust the temperature of the sulfuric acid solution being delivered to a temperature of 20 to 60° C. The temperature of the solution contained in the treatment tank 5 may also be adjusted to this temperature.

[0066] In the electrolysis cell 10, a voltage is applied between the anode 10A and the cathode 10B by the electrolysis DC power supply 7, causing a current to flow, and the sulfuric acid solution flowing through the flow path is electrolyzed by the anode 10A, the cathode 10B, and the bipolar electrode 10C, thereby producing an electrolytic sulfuric acid solution such as peroxodisulfuric acid.

[0067] The produced electrolytic sulfuric acid solution is supplied to the treatment tank 5 via the introduction line 9A. When the sulfuric acid solution in the treatment tank 5 is produced as an electrolytic sulfuric acid solution, the process proceeds to a resin peeling step (step S11). Electrolysis by the electrolytic sulfuric acid device 6 continues even during the resin peeling step. In this embodiment, the device having bipolar electrodes has been described, but the presence or absence of bipolar electrodes is not particularly limited in this embodiment.

[0068] In this embodiment, the apparatus shown in Fig. 1 is used, but the electrolysis method is not particularly limited and is not limited to the apparatus shown in Fig. 1. For example, in each of the above embodiments, a treatment tank 5 and an electrolytic cell 10 are provided, but it is also possible to use a common tank to perform stripping and decomposition. However, it is more efficient to perform stripping and decomposition in separate devices (tanks).

[0069] In the coating material peeling and removal step (step S11), the aluminum wire 2 coated with the insulating coating material is immersed in an electrolytic sulfuric acid solution. The temperature of the electrolytic sulfuric acid solution is preferably heated to 60° C. or higher.

[0070] The electrolyzed sulfuric acid solution comes into contact with the coating material on the aluminum wire 2, thereby effectively peeling and removing the coating material from the aluminum wire 2. Compared to sulfuric acid solutions that do not contain an oxidizing agent, the electrolytic sulfuric acid solution has a stronger oxidizing power, so it can uniformly and thinly oxidize the surface of the aluminum wire, thereby suppressing excessive oxidation and minimizing dissolution of the aluminum wire and peeling and removing the coating material.

[0071] Furthermore, the stripped material removed from the coated aluminum wire dissolves in the electrolytic sulfuric acid solution. The aluminum wire from which the coating material has been peeled off is transferred to a cleaning and drying step in the same manner as in the previous embodiment (aluminum wire cleaning and drying step; step S12). At the same time, in the dissolved electrolytic sulfuric acid solution, the coating site-utilizing components are decomposed by the oxidizing agent in the electrolytic sulfuric acid solution, and the sulfuric acid solution is regenerated (sulfuric acid solution regeneration step; step S13). According to this embodiment, the peeling and removal of the coating material from the aluminum wire and the decomposition of the coating material components dissolved in the electrolytic sulfuric acid solution can be carried out simultaneously, and the treatment can be carried out efficiently.

[0072] (Embodiment 4) In each of the above embodiments, the coated aluminum material was brought into contact with the sulfuric acid solution by immersing the coated aluminum material in the sulfuric acid solution, but the coated material can also be brought into contact with the sulfuric acid solution by any appropriate method, such as spraying or flowing the sulfuric acid solution. 6 shows a treatment device 1B in which a treatment tank 5 is provided with a nozzle 12 for spraying a sulfuric acid solution downward. The treatment tank 5 in this configuration is the sulfuric acid solution contact section in the present disclosure and corresponds to a release contact tank. Note that the same components as those in the above embodiment are denoted by the same reference numerals, and their description will be omitted or simplified.

[0073] An aluminum wire 2 coated with a coating material is placed on a stage 13 below the nozzle 12, and a sulfuric acid solution is sprayed downward from the nozzle 12 to bring the coating material into contact with the sulfuric acid solution. The coating material is peeled off and removed from the aluminum wire 2, and is stored in a decomposition storage tank 14 from the treatment tank 5A via a feed line 15A. The peeled off coating material dissolves in the sulfuric acid solution. As in the above-described embodiment, this sulfuric acid solution can be electrolyzed in the electrolytic sulfuric acid device 6, decomposed with a sulfuric acid solution containing persulfuric acid solution, and regenerated. The regenerated sulfuric acid solution can be sent to the nozzle 12 via the return line 15B by the liquid feed pump 16 and used in the peeling and removal process. The feed line 15A and the return line 15B constitute a decomposition / regeneration liquid feed path.

[0074] (Embodiment 5) In each of the above-mentioned first embodiments, the embodiment having one treatment tank has been described, but it may have a plurality of treatment tanks. A fifth embodiment will be described with reference to FIG. In this embodiment, there are two treatment tanks, a first treatment tank 5A and a second treatment tank 5B, and one electrolytic sulfuric acid device 6. The first treatment tank 5A and the second treatment tank 5B are each connected to the electrolytic sulfuric acid device 6 by an inlet line and an outlet line, and the first treatment tank 5A and the second treatment tank 5B can be connected to the electrolytic sulfuric acid device 6 by switching the inlet line and the outlet line. As in the first embodiment, the electrolytic sulfuric acid device 6 is equipped with an anode, a cathode, a bipolar electrode, and a DC power supply for electrolysis.

[0075] In this embodiment, one treatment tank, for example, the first treatment tank 5A, is used, and the aluminum wire coated with the coating material is immersed in a sulfuric acid solution to peel off and remove the coating material (A in FIG. 7). When the decomposition rate of the coating film in the first treatment tank 5A decreases, it is determined that the peeling and removal capacity is insufficient, and the aluminum wire is removed. Sulfuric acid solution is circulated between the aluminum wire and the electrolytic sulfuric acid device 6, and electrolytic sulfuric acid is generated in the electrolytic sulfuric acid device 6, thereby decomposing the coating film components and regenerating sulfuric acid. Meanwhile, the other second treatment tank 5B contains a sulfuric acid solution, and another aluminum wire covered with a coating film is immersed in the sulfuric acid solution to peel off and remove the coating film (B in FIG. 7). When the solubility in the second treatment tank 5B decreases in this state, the aluminum wire is removed, and the coating components are decomposed to regenerate sulfuric acid while the solution is circulated between the second treatment tank 5B and the electrolytic sulfuric acid device 6. In the other first treatment tank 5A, the aluminum wire coated with the coating film is immersed in the regenerated sulfuric acid solution to remove the coating film (C in Fig. 7).

[0076] By repeating the above procedure, multiple resins can be continuously treated without interrupting the process. In this embodiment, the description is given of a system equipped with two treatment tanks, but the number is not particularly limited, and the system may be equipped with two or more electrolytic sulfuric acid devices. In a specific embodiment of the apparatus for carrying out the coating material stripping method, a plurality of tanks for stripping and removing the coating material are prepared, and stripping and removing the coating material in a tank is terminated according to a decrease in the decomposition rate of the coating material in that tank, and the sulfuric acid solution in that tank is electrolyzed. Upon termination of the stripping and removing of the coating material, stripping and removing of the coating material in another tank can be continued or started.

[0077] (Embodiment 6) Next, another embodiment will be described with reference to Fig. 8. Note that the same components as those in the above-described embodiments are given the same reference numerals, and the description thereof will be omitted or simplified.

[0078] The treatment device 1C has multiple treatment tanks (treatment tanks 50A, 50B, 50C, 50D) that contain sulfuric acid solution and in which coated aluminum materials are immersed, and further has a decomposition storage tank 30 that contains sulfuric acid solution in which coating resin is dissolved, and an electrolytic sulfuric acid device 6. Treatment tanks 50A, 50B, 50C, and 50D are sulfuric acid contact units and correspond to immersion contact tanks in the present disclosure. A measurement unit 11 is disposed in decomposition storage tank 30 and is immersed in the sulfuric acid solution to measure the electrical conductivity or oxidation-reduction potential of the sulfuric acid solution.

[0079] Between the treatment tanks 50A, 50B, 50C, and 50D and the decomposition storage tank 30, there are provided an outlet path 29A for sending the sulfuric acid solution treated in the treatment tank to the decomposition storage tank 30, and an inlet path 29B for sending the sulfuric acid solution regenerated in the decomposition storage tank 30. The outlet path 29A is provided with a liquid feed pump 32A, and the inlet path 29B is provided with a liquid feed pump 32B. Furthermore, the inlet path 29B is provided with a heating unit 28 for heating the sulfuric acid solution to be sent. The outlet path 29A and the inlet path 29B branch off and are connected to the treatment tanks 50A, 50B, 50C, and 50D, respectively. The outlet path 29A and the inlet path 29B constitute the decomposition / regeneration liquid feed paths of the present disclosure.

[0080] In addition, between the decomposition storage tank 30 and the electrolytic sulfuric acid device 6, there are provided an inlet path 31A for sending the sulfuric acid solution from the electrolytic sulfuric acid device 6 to the decomposition storage tank 30, and an outlet path 31B for sending the sulfuric acid solution from the decomposition storage tank 30 to the electrolytic sulfuric acid device 6, and the outlet path 31B is provided with a circulation pump 33 and a cooling unit 34 for cooling the sulfuric acid solution. A control unit 20 is also provided which receives the measurement results of the measurement unit 11 and controls the operations of the liquid delivery pumps 32A and 32B and the circulation pump 33.

[0081] Next, the operation of the processing device 1C will be described. The treatment tanks 50A, 50B, 50C, and 50D contain sulfuric acid solutions, which are preferably maintained at a temperature of 60 to 140°C. In all or part of these treatment baths 50A, 50B, 50C, and 50D, copper wires coated with a coating material are immersed in a sulfuric acid solution to dissolve and peel off the coating material.

[0082] At the beginning of operation, the sulfuric acid solution is stored in the decomposition storage tank 30, and the sulfuric acid solution can be sent to the necessary treatment tanks 50A, 50B, 50C, and 50D through the inlet line 29B by the liquid feed pump 32B. At this time, the sulfuric acid solution can be heated to a desired temperature (for example, 60 to 140°C) by the heating unit 28. Note that an electromagnetic valve may be provided at each branch of the inlet line 29B, and the treatment tank to which the solution is sent may be selected by controlling the opening and closing of the electromagnetic valve by the control unit 20.

[0083] The sulfuric acid solution in which the coating material has been dissolved in the treatment tanks 50A, 50B, 50C, and 50D is sent by the liquid feed pump 32A through the delivery path 29A to the decomposition storage tank 30. The state of dissolution in the treatment tank may be checked visually, but an appropriate dissolution measurement unit such as a unit for measuring the solution permeability may also be used, and the results may be received by the control unit 20, which then compares the results with a dissolution reference value to determine whether the stripping is complete. In this case, the control unit 20 can control the opening and closing of the solenoid valves in each branch path and the liquid feed pump 32A to send the liquid.

[0084] Once the sulfuric acid solution in which the coating material has been dissolved is contained in the decomposition storage tank 30, the circulation pump 33 is operated to circulate the sulfuric acid solution between the decomposition storage tank 30 and the electrolytic sulfuric acid device 6, thereby electrolyzing the sulfuric acid solution. During circulation, the sulfuric acid solution sent from the decomposition storage tank 30 is cooled (e.g., to 20 to 60°C) by a cooling unit 34 provided in the delivery line 31B. Persulfuric acid is produced from the sulfuric acid solution by electrolysis in the electrolytic sulfuric acid device 6, and is sent to the decomposition storage tank 30 through the introduction line 31A. At this time, the persulfuric acid concentration is preferably 0.5 to 5.0 g / L.

[0085] In the decomposition reservoir 30, the components of the coating material dissolved in the sulfuric acid solution are gradually decomposed by the sulfuric acid solution containing persulfuric acid that has been introduced. By continuing the above-mentioned operation, the concentration of the coating material dissolved in the sulfuric acid solution gradually decreases. The decomposition status of the coating material in the sulfuric acid solution is measured by the measurement unit 11 and transmitted to the control unit 20. The control unit 20 determines whether the measurement result reaches a reference value, and if not, continues circulating the sulfuric acid solution and electrolysis. If the measurement value reaches the reference value, it determines that decomposition is complete, stops the application of voltage to the electrolytic treatment device 6, and stops the operation of the circulation pump 33. Next, the liquid supply pump 32B is operated to supply the sulfuric acid solution from the decomposition storage tank 30 to one or all of the treatment tanks 50A, 50B, 50C, and 50D, and reuses it for peeling and removing the coated aluminum material. The regenerated sulfuric acid solution may be used for other purposes in addition to the same purpose. The reference value in the control unit 20 may be set in advance and stored in a nonvolatile storage unit, or may be acquired from a server or the like via a network, etc. Different values ​​may be set as the reference value depending on the type of coating material, etc.

[0086] In the above embodiment, the peeling and regeneration treatment of the coated aluminum material was described without specifying a treatment tank, but these treatments may be performed simultaneously in multiple treatment tanks, or sequentially. By performing the treatment sequentially in multiple treatment tanks, efficient treatment can be achieved without waste.

[0087] Although the present invention has been described above based on the above embodiment, appropriate modifications can be made without departing from the scope of the present invention. Magnet wire is generally made of aluminum material coated with insulating resin. Examples of resins used for the insulating coating that coats aluminum material include polyimide resin, polyesterimide resin, polyamideimide resin, polyurethane resin, and polyester resin. The resin-coated aluminum wire processed in this embodiment uses the same insulating material as copper wire. Any insulating resin may be used in this embodiment, and the insulating resin is not limited to a specific resin. The resin-coated aluminum wire may be in any shape, such as a rectangular wire or a round wire, and may be processed not only as a single resin-coated aluminum wire but also in a state such as being wound into a coil. The present embodiment can be suitably used as a method for peeling and removing an insulating coating from a resin-coated aluminum wire, which is an aluminum wire for winding electronic devices used in automobiles, home appliances, industrial applications, etc., and recovering the aluminum wire, but the uses of the present embodiment are not limited to these uses. [Example]

[0088] [Conditions for peel-treated test specimens] The test pieces were cut to a length of approximately 150 mm from magnet wires having polyimide insulating coatings with different peeling conditions. Aluminum wire cross section: diameter 1.15mm Nominal coating thickness: 27.5 μm [Specifications of the peeling treatment tank] Treatment tank 5 volume: 25L

[0089] (Examples 1 and 2) In Example 1, the coating film removal treatment was carried out using a 94.0 mass % sulfuric acid solution at a solution temperature of 100° C., and in Example 2, the coating film removal treatment was carried out using a 92.0 mass % sulfuric acid solution at a solution temperature of 110° C. After visually determining that the treatment was complete, the remaining aluminum rate was determined. In order to visually determine the completion of the treatment, a standard chart has been created that lists the surfaces of various magnet wires treated for different times and the results of checking the presence or absence of an insulating coating using an analytical device.

[0090] Examples 3 to 5 The coating treatment was carried out using an electrolytic sulfuric acid solution. Example 3 was the same as Example 1 except for the use of an electrolytic sulfuric acid solution. In Example 4, the coating treatment was carried out at 92.0 mass % and a solution temperature of 110°C, and in Example 5, the coating treatment was carried out at 90.0 mass % and a solution temperature of 120°C. [Production of electrolytic sulfuric acid solution] The treatment conditions for electrolyzing the sulfuric acid solution are as follows: Material of anode 10A and cathode 10B: Diamond electrode (diameter 150 mm) Bipolar electrode 10C material: Diamond electrode (diameter 150mm) ·Current density: 5~30A / dm 2 Electrolysis cell circulation flow rate: 2-3L / min

[0091] (Comparative Example 1) The coating treatment was carried out using an alkaline stripping solution containing potassium hydroxide, monoethanolamine, and phosphoric acid as the main components, at 95°C. The treatment solution volume was 1 L. The test pieces and other materials used were the same as those used in Example 1.

[0092] [Table 1]

[0093] The oxidant concentration in each test example was determined by taking a portion of the electrolyzed solution, subjecting it to a starch-iodine reaction, and then neutralizing it to determine the total oxidizing power (KI value) of the solution. The solution was also titrated with potassium permanganate to measure the amount of hydrogen peroxide in the solution, and this value was subtracted from the KI value to determine the oxidizing power of the solution.

[0094] In Reference Example 1, treatment was carried out under the conditions of Example 1 for the same time as in Example 3. Although the stripping treatment progressed, it was found that the insulating film could not be completely removed within the set treatment time (the same time as in Example 3), and that a longer treatment time was required. It was also found that the treatment for stripping and removal of the insulating film could be carried out more efficiently in a sulfuric acid solution containing persulfuric acid, as in Examples 3-5. In Reference Example 2, the treatment was performed with a sulfuric acid concentration lower than the desired value. Although the peeling treatment progressed, the treatment could not be completed within 180 minutes of treatment, so the treatment was interrupted after 180 minutes of treatment. It was found that the treatment efficiency decreased when the sulfuric acid concentration was lower than the desired value. In Reference Examples 1 and 2, the peeling and removal of the coating was not completed, so the remaining rate of the aluminum material was not measured. [Explanation of symbols]

[0095] 1 Processing equipment 1A Processing equipment 1B Processing equipment 1C Processing Unit 2. Aluminum wire 3. Bubble Generator 4. Air pump 5 Treatment tank 5A First treatment tank 5B Second treatment tank 6 Electrolytic sulfuric acid equipment 7 DC power supply for electrolysis 8 Circulation Pump 9A Inlet path 9B Sending path 10 Electrolysis Cell 10A anode 10B Cathode 10C Bipolar Electrode 11 Measuring part 12 nozzles 14 Decomposition storage tank 15A feed line 15B Return line 16 Liquid transfer pump 20 Control Unit 28 Heating section 29A Sending path 29B Introductory path 30 Decomposition storage tank 31A Inlet path 31B Sending path 32A Liquid Transfer Pump 32B Liquid transfer pump 33 Circulation Pump 34 Cooling section 50A treatment tank 50B Treatment tank 50C treatment tank 50D treatment tank

Claims

1. A method for stripping a coated aluminum material, comprising contacting a coating material coated on an aluminum material with a sulfuric acid solution, dissolving the coating material in the sulfuric acid solution, and stripping and removing the coating material from the aluminum material, and then decomposing the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution containing persulfuric acid.

2. 2. The method for stripping a coated aluminum material according to claim 1, wherein the concentration of persulfuric acid in the electrolytic sulfuric acid solution is 0.5 g / L or more.

3. 3. The stripping method according to claim 1, wherein the sulfuric acid solution used to decompose the coating material is reused for stripping and removing the coated aluminum material or other coated aluminum materials.

4. 3. The stripping treatment method according to claim 1, wherein the sulfuric acid solution brought into contact with the coating material coating the aluminum material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 94.0 mass% or more, and a temperature within a range of 60 to 140°C.

5. The sulfuric acid solution to be brought into contact with the coating material coated on the aluminum material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more in part or all of the peeling and removal process, and the sulfuric acid concentration is 94.0 mass% or more and the temperature is in the range of 60 to 140 ° C. The stripping treatment method according to claim 1 or 2.

6. 3. The stripping treatment method according to claim 1, wherein the sulfuric acid solution brought into contact with the coating material coating the aluminum material has a persulfuric acid concentration of less than 0.5 g / L, a sulfuric acid concentration of 90.0 mass% or more and less than 94.0 mass%, and a temperature within a range of 60 to 140°C.

7. The sulfuric acid solution to be brought into contact with the coating material coated on the aluminum material is an electrolytic sulfuric acid solution having a persulfuric acid concentration of 0.5 g / L or more in part or all of the peeling and removal process, and the sulfuric acid concentration is 90.0 mass% or more but less than 94.0 mass%, and the temperature is in the range of 60 to 140 ° C. The stripping treatment method according to claim 1 or 2.

8. 3. The stripping treatment method according to claim 1, wherein the electrolytic sulfuric acid solution is electrolyzed at a solution temperature of 20 to 60°C.

9. 3. The stripping method according to claim 1, wherein the decomposition state of the coating material is determined by one or both of the electrical conductivity and the oxidation-reduction potential of the sulfuric acid solution.

10. 10. The stripping method according to claim 9, wherein when the decomposition state of the coating material reaches a standard, it is determined that the regeneration is complete, and the regenerated sulfuric acid solution is used to strip and remove the coated aluminum material.

11. A peeling and removal treatment device having a sulfuric acid solution contact section that brings a sulfuric acid solution into contact with a coating material of a coated aluminum material, and a decomposition section that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution.

12. 12. The peeling and removal treatment device according to claim 11, wherein the sulfuric acid solution contact section has one or both of an immersion treatment tank for immersing the coated aluminum material in the sulfuric acid solution and a release contact tank for releasing the sulfuric acid solution onto the coated material to contact it.

13. The peeling and removal treatment device according to claim 11 or 12, wherein the decomposition unit is provided with an electrolysis unit that electrolyzes a sulfuric acid solution.

14. The peeling and removal treatment device according to claim 13, wherein the sulfuric acid solution contacting section is provided in a plurality of sections, and one or more of the electrolysis sections are capable of selectively electrolyzing the sulfuric acid solutions in the plurality of sulfuric acid solution contacting sections.

15. 13. The peeling and removal treatment device according to claim 11, wherein the decomposition section comprises a decomposition storage tank and an electrolysis section, and an electrolysis circulation path for circulating a sulfuric acid solution between the decomposition storage tank and the electrolysis section.

16. 16. The peeling and removal treatment device according to claim 15, further comprising a decomposition and regeneration liquid transfer path between the sulfuric acid solution contact section and the decomposition storage tank.

17. a measurement unit for measuring the decomposition state of the sulfuric acid solution in the decomposition unit; a control unit that controls electrolysis in the electrolysis unit, and liquid transfer through the electrolysis circulation path and the decomposition / regeneration liquid transfer path; The peeling and removal processing apparatus according to claim 16 , wherein the control unit receives the measurement result of the measurement unit and determines the content of the control based on the measurement result.

18. The apparatus is provided in a treatment device having a measuring section for measuring the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, a sulfuric acid solution contact section for dissolving the coating material of the coated aluminum material by contact with the sulfuric acid solution to peel and remove it, a decomposition storage tank for decomposing the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution, a decomposition / regeneration liquid transfer path provided between the sulfuric acid solution contact section and the decomposition storage tank, an electrolysis section for electrolyzing the sulfuric acid solution, and an electrolysis circulation path for circulating the sulfuric acid solution between the decomposition storage tank and the electrolysis section, receiving the measurement result of the measurement unit, and controlling the electrolysis of the electrolysis unit and the liquid transfer through the electrolysis circulation path and the decomposition / regeneration liquid transfer path; a processing device control unit that receives the measurement results and performs control to determine the content of the control based on the measurement results;

19. A program executed by a control unit that receives a measurement result from a measurement unit that measures the decomposition state of a coating material in a sulfuric acid solution containing persulfuric acid, and controls: a sulfuric acid solution contact unit that dissolves the coating material of the coated aluminum material by contact with the sulfuric acid solution to peel and remove it; and a decomposition storage tank that decomposes the coating material dissolved in the sulfuric acid solution with an electrolytic sulfuric acid solution; a decomposition and regeneration liquid supply path that is provided between the sulfuric acid solution contact unit and the decomposition storage tank; electrolysis in an electrolysis unit that electrolyzes the sulfuric acid solution; and a liquid supply through an electrolysis circulation path that circulates the sulfuric acid solution between the decomposition storage tank and the electrolysis unit, The program includes a step of sending the sulfuric acid solution in which the coating material has been dissolved in the sulfuric acid solution contact portion to a decomposition storage tank through a decomposition / regeneration liquid sending path; receiving the measurement results; Executing electrolysis by the electrolysis unit and sending the solution through the electrolysis circulation path until the measurement result reaches a standard; When the measurement result reaches a reference value, electrolysis by the electrolysis unit is stopped, and the sulfuric acid solution in the decomposition storage tank is sent to the sulfuric acid solution contact unit through the decomposition / regeneration liquid sending path. A program to be executed by the control unit.

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