Enameled wire copper recovery method

Abstract

The invention provides a method for recovering copper of an enameled wire, which can reduce environmental load and recover high-purity copper at lower processing cost. The copper recovery method for an enameled wire is a method for recovering copper or a copper alloy constituting a conductor (21) by removing an insulator (22) from an enameled wire (2) having the insulator (22) around the conductor (21) comprising copper or a copper alloy. The method is provided with a peeling step for performing compression processing or rolling processing on the enameled wire (2) to peel off the insulator (22) from the conductor (21), and a removal step for peeling off and removing the insulator (22) peeled off from the conductor (21).

Description

Technical Field

[0001] The invention relates to a method for recovering copper of an enameled wire. Background Art

[0002] Enameled wires are known in which a conductor is coated with wire enamel paint and dried to form an insulator. It is known that the conductor and the insulator have high adhesion in the enameled wire, so it is difficult to remove the insulator from the conductor and recover copper when the enameled wire is discarded.

[0003] Patent Document 1 discloses a method of removing the insulation of an enameled wire by heating it to carbonize it and then applying a mechanical external force, and Patent Document 2 discloses a method of removing the insulation by immersing the enameled wire in an alkaline solution to hydrolyze the insulation.

[0004] Prior art literature

[0005] Patent Literature

[0006] Patent Document 1: Japanese Patent Application Publication No. 2011-174175

[0007] Patent Document 2: Japanese Patent Application Laid-Open No. 10-25523 Summary of the invention

[0008] Problems to be solved by the invention

[0009] However, in the method described in Patent Document 1, heating to a high temperature of 500° C. or higher is required to carbonize the insulator, which requires huge thermal energy, thus increasing the processing cost. In addition, the conductor may oxidize during heating, or carbides may be integrated with the conductor, and the purity of the copper that can be recovered may be reduced.

[0010] The method described in Patent Document 2 requires a high-concentration alkaline solution, which increases the cost of chemicals and the waste liquid treatment, which has a large environmental load and increases the treatment cost. In addition, heating is required to hydrolyze the insulator, which further increases the treatment cost.

[0011] Therefore, an object of the present invention is to provide a method for recovering copper from enameled wires, which can reduce environmental load and recover high-purity copper at a low processing cost.

[0012] Methods for solving problems

[0013] The present invention aims to solve the above-mentioned problems and provides a method for recovering copper from an enameled wire, wherein the insulator is removed from the enameled wire having an insulator around a conductor made of copper or a copper alloy, and the copper or copper alloy constituting the conductor is recovered. The copper recovery method comprises a stripping step of subjecting the enameled wire to a compression process or a rolling process so as to strip the insulator from the conductor, and a removal step of stripping and removing the insulator stripped from the conductor.

[0014] Effects of the Invention

[0015] According to the present invention, a method for recovering copper from an enameled wire can be provided, which can reduce environmental load and recover high-purity copper at a low processing cost. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 This is a schematic configuration diagram of an enameled wire copper recovery device used in an enameled wire copper recovery method according to one embodiment of the present invention.

[0017] Figure 2 (a) and (b) are diagrams for explaining compression processing.

[0018] Figure 3 The photographs show an example of enameled wire after compression processing, (a) is after punching once, (b) is after punching twice, and (c) is a photograph when a slit is cut by a knife blade in (b).

[0019] Figure 4 In the drawings, (a) is a photograph showing a cross section of the enameled wire before compression processing, and (b) is a photograph showing a cross section of the enameled wire after compression processing.

[0020] Figure 5 It is a figure explaining the rolling process.

[0021] Figure 6 It is a perspective view showing an example of a removing device.

[0022] Figure 7 This is a diagram showing the results of studying the processing conditions of compression processing (press processing).

[0023] Figure 8 This is a flow chart of a method for recovering copper from an enameled wire according to one embodiment of the present invention.

[0024] Description of Reference Numerals

[0025] 1 ... copper recovery device for enameled wire, 2 ... enameled wire, 21 ... conductor, 22 ... insulator, 3 ... stripping device, 31 ... punching machine, 32 ... rolling processing machine, 4 ... removal device, 41 ... blade. DETAILED DESCRIPTION

[0026] Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings.

[0027] Figure 1 1 is a schematic diagram of a copper recovery device 1 for an enameled wire (hereinafter referred to as the copper recovery device 1) used in the copper recovery method for an enameled wire of the present embodiment. Figure 1 As shown, the copper recovery device 1 is a device for removing the insulator 22 from the conductor 21 of the enameled wire 2 to recover the copper or copper alloy constituting the conductor 21 , and includes a stripping device 3 and a removal device 4 .

[0028] The enameled wire 2 is, for example, an electric wire used in a motor, a transformer, an induction heating coil, etc. for a vehicle. The enameled wire 2 may be a round wire with a circular cross section, or a flat wire with a rectangular cross section. In addition, the enameled wire 2 is not limited to a round wire or a flat wire, and for example, the cross section may be an elliptical shape or a triangular shape, and the cross section shape is not particularly limited. The enameled wire 2 has a conductor 21 made of copper or a copper alloy and an insulator 22 formed by applying a wire varnish coating around the conductor 21 and sintering it. The insulator 22 is made of, for example, polyimide, polyamide-imide, polyester, polyurethane, polyester-imide, etc.

[0029] In the enameled wire 2, it is known that the insulator 22 has a high adhesion to the conductor 21. Therefore, when the enameled wire 2 is discarded, it is not easy to remove the insulator 22 from the conductor 21 and recover the conductor 21 (that is, to recover the copper or copper alloy constituting the conductor 21). In the copper recovery device 1 of the present embodiment, even in the enameled wire 2 where the adhesion between the conductor 21 and the insulator 22 is high, the insulator 22 can be easily removed and the copper or copper alloy constituting the conductor 21 can be easily recovered. The following is a detailed description.

[0030] (Peeling device 3)

[0031] The stripping device 3 is a device that performs a stripping step of stripping the insulator 22 from the conductor 21 by subjecting the enameled wire 2 to compression (pressing) or rolling.

[0032] Figure 2 (a) and (b) are figures for explaining compression processing (stamping processing). When the stripping device 3 is used for compression processing, a punching machine 31 for compression processing is used as the stripping device 3. In the compression processing, the enameled wire 2 is flattened in a direction perpendicular to the length direction. It is particularly preferred to move the enameled wire 2 along the length direction and continuously perform compression processing along the length direction of the enameled wire 2. In the present embodiment, a flat wire is used as the enameled wire 2, and in the stripping process, compression processing is performed by punching in the short axis direction of the enameled wire 2. At this time, by arranging a gauge block 311 between the punching machines 31, the enameled wire 2 is formed to the same thickness as the gauge block 311.

[0033] By implementing compression processing, such as Figure 2 As shown in (b), the enameled wire 2 is deformed in a manner of expanding in a direction perpendicular to the punching direction, and a compressive stress acts in the punching direction (the short axis direction of the enameled wire 2), and a tensile stress acts in the direction perpendicular to the punching direction (the long axis direction of the enameled wire 2). In addition, the enameled wire 2 is stretched in the long axis direction of the enameled wire 2, and a shear stress is generated at the interface between the conductor 21 and the insulator 22 due to the difference in the elongation of the conductor 21 and the insulator 22, resulting in local peeling between the conductor 21 and the insulator 22. By forming a slit 22a in the peeling portion (compressed surface) using the blade 41 of the removal device 4 described later, the insulator 22 can be removed from the conductor 21.

[0034] In the compression process, multiple punching may be performed at any position in the length direction of the enameled wire 2. By performing multiple punching, it is easier to produce a local peeling portion between the conductor 21 and the insulator 22. In addition, in the compression process, the enameled wire 2 may be repeatedly moved after punching and punched again, and the entire enameled wire 2 in the length direction may be punched sequentially.

[0035] Figure 3 This is a photograph showing an example of the enameled wire 2 after compression processing. Figure 3 (a) is a photo after punching once, (b) is a photo after punching twice, and (c) is a photo of the slits cut by the blade after punching twice. Figure 4 (a) is a photograph showing a cross section of the enameled wire 2 before compression processing, Figure 4 (b) is a photograph showing a cross section of the enameled wire 2 after compression processing. Figure 4 In (b), a state where a slit 22a is cut on the insulator 22 by a blade is shown. Figure 3 , Figure 4 As shown, it was confirmed that the insulator 22 can be peeled off from the conductor 21 by performing the compression process. It should be noted that preferred processing conditions during the compression process will be described later.

[0036] Figure 53 is a diagram for explaining rolling processing. When rolling processing is performed in the stripping process, a rolling processing machine 32 for performing rolling processing is used as the stripping device 3. In the rolling processing machine 32, the enameled wire 2 is passed between a pair of rollers 321, thereby performing stretching processing while compressing the enameled wire 2. In the rolling processing machine 32, the roller 321 rotates at a position in contact with the enameled wire 2 in such a manner that the outer peripheral surface of the roller 331 moves in the same direction as the traveling direction of the enameled wire 2. In the rolling processing, the enameled wire 2 is stretched in a direction perpendicular to the compression direction (the opposing direction of the roller 321) in the same manner as the above-mentioned compression processing, and shear stress is generated at the interface between the conductor 21 and the insulator 22 due to the difference in the elongation of the conductor 21 and the insulator 22, and a local stripping portion is generated between the conductor 21 and the insulator 22.

[0037] (Removal device 4)

[0038] The removal device 4 is a device that performs a removal step of peeling and removing the insulator 22 peeled from the conductor 21 by the peeling device 3 . Figure 6 4 is a diagram showing an example of the removal device 4. Figure 6 As shown, the removing device 4 continuously cuts slits 22 a along the longitudinal direction of the insulator 22 after the stripping step using a blade 41 , and continuously strips the insulator 22 divided by the slits 22 a , thereby removing the insulator 22 from the conductor 21 .

[0039] In the present embodiment, a pair of blades 41 are arranged at positions opposed to each other up and down across the center of the enameled wire 2, and each blade 41 is used to form a slit 22a along the length direction of the enameled wire 2, thereby continuously dividing the insulator 22 into two parts on the left and right. Then, the divided insulator 22 is opened on the left and right sides, and each insulator 22 is guided to the winding roller 43 via the guide roller 42. While the enameled wire 2 is moved, the winding roller 43 is used to wind up the insulator 22, thereby pulling the insulator 22 to the left and right, and continuously stripping the insulator 22 from the conductor 21. It should be noted that the up and down and left and right directions mentioned here are relative directions, and are not limited to the vertical direction and the horizontal direction.

[0040] The winding tension of the winding roller 43 on the insulator 22 can be greater than 5% and less than 90% of the breaking strength of the insulator 22. It should be noted that the breaking strength of the insulator 22 refers to the value measured by cutting the insulator 22 into a strip with a width of 1 mm from the enameled wire 2, and then using an automatic plotter to perform a tensile test with a distance between points of 30 mm and a tensile speed of 10 mm / min. As a result, the insulator 22 will not bend or break, and the insulator 22 can be stably stripped off. In addition, when stripping the insulator 22 from the conductor 21, the angle θ formed by the direction in which the insulator 22 is stretched and the running direction of the enameled wire 2 is preferably greater than 30 degrees and less than 160 degrees, and preferably greater than 90 degrees and less than 160 degrees. As a result, it is easy to strip the insulator 22 from the conductor 21, and the breakage of the insulator 22 during winding can also be suppressed. It should be noted that Figure 6 The removal device 4 is just an example, and the specific structure of the removal device 4 can be changed appropriately.

[0041] (Preferred processing conditions for the peeling step)

[0042] The compression process (pressing process) was performed while changing the processing conditions to confirm whether the insulator 22 could be easily stripped from the enameled wire 2 after the processing. The results are shown in FIG. Figure 7 It should be noted that Figure 7 In FIG. 1 , the region where the insulator 22 can be easily peeled off is indicated by hatching. In addition, a flat wire is used as the enameled wire 2, and a punch is applied in the short axis direction thereof.

[0043] like Figure 7 As shown, in the case of compression processing, it can be said that it is preferable to process in a manner where the thickness change rate is 54.5% or more. It should be noted that if the thickness of the enameled wire 2 before processing (for example, the thickness in the short axis direction of the flat wire) is set to A and the thickness of the enameled wire 2 after processing is set to B, the thickness change rate can be obtained by the following formula.

[0044] Thickness change rate (%) = {(AB) / A} × 100

[0045] In addition, according to Figure 7 It can be said that in the case of compression processing, it is preferred to process in a manner where the rate of change of the Vickers hardness is 105.5% or more. It should be noted that, regarding the rate of change of the Vickers hardness, when the Vickers hardness before processing is set to C and the Vickers hardness after processing is set to D, it can be obtained by the following formula. It should be noted that the Vickers hardness is measured by the method described in JIS Z2244 (2009). The measurement conditions are set to a load of 200g and a holding time of 15 seconds. The cross section of the sample is mirror-polished, and the average value of the values ​​measured at two locations near the center of the conductor 21 is used.

[0046] Change rate of Vickers hardness (%) = {(DC) / C} × 100

[0047] Figure 7 The example of compression processing is shown, but the same conditions as above are also preferably used in rolling processing. That is, in the case of rolling processing in the stripping process, it can be said that it is also preferably processed in a manner where the thickness change rate is 54.5% or more and the Vickers hardness change rate is 105.5% or more, as in the case of compression processing.

[0048] (Copper recovery method for enameled wire)

[0049] Figure 8 Flow chart of the copper recovery method of the enameled wire of this embodiment. Figure 8 As shown, in the copper recovery method of the enameled wire of the present embodiment, the copper or copper alloy constituting the conductor 21 of the enameled wire 2 is recovered by continuously repeating the stripping step of step S1 and the removing step of step S2.

[0050] In the stripping process of step S1, the enameled wire 2 is subjected to compression or rolling processing using the stripping device 3, so that the insulator 22 is stripped from the conductor 21. At this time, the processing is performed in a manner that the thickness change rate is 54.5% or more and the Vickers hardness change rate is 105.5% or more. It should be noted that in the stripping process, the entire insulator 22 does not need to be stripped from the conductor 21, and stripping may be caused in a part of the insulator 22 in a manner that becomes the starting point of stripping.

[0051] In the removal process of step S2, the insulator 22 peeled off from the conductor 21 is peeled off and removed using the removal device 4. Figure 6 As shown in the figure, the insulator 22 after the stripping process is continuously cut with the blade 41 along the length direction, and the insulator 22 divided by the slits 22a is continuously stripped, thereby removing the insulator 22 from the conductor 21. The portion where the slits 22a are cut is preferably a compressed surface that has been subjected to compression or rolling. However, the present invention is not limited to this, and any method can be used to remove the insulator 22 as long as the insulator 22 can be stripped and removed. The conductor 21 after the insulator 22 is removed is wound up by, for example, a winding drum and recovered.

[0052] (Functions and Effects of Implementation Methods)

[0053] As described above, the copper recovery method of the enameled wire of the present embodiment includes a stripping step of compressing or rolling the enameled wire 2 to strip the insulator 22 from the conductor 21 and a removing step of stripping and removing the insulator 22 stripped from the conductor 21 .

[0054] By performing compression or rolling, the difference between the elongation of the conductor 21 and the elongation of the insulator 22 can be utilized to peel the insulator 22 from the conductor 21, and the insulator 22 can be easily peeled off from the conductor 21. In this embodiment, since no chemicals that require waste liquid treatment are used, the environmental load is small. In addition, since no heating treatment is required, the conductor 21 will not be oxidized, and the carbonized insulator 22 will not be integrated with the conductor 21, and high-purity copper can be recovered. In addition, in this embodiment, there is no need to perform treatment using chemicals with high treatment costs, and general compression or rolling equipment can be used. Therefore, the equipment cost and treatment cost are very low, and copper or copper alloy can be recovered at a low cost.

[0055] (Variation Example)

[0056] In the above embodiment, the stripping process and the removal process are performed on one production line. However, the production line may be divided into each process by temporarily winding the enameled wire 2 after the stripping process and then performing the removal process on the wound enameled wire 2. In addition, in the stripping process, both compression and rolling may be performed to make the insulator 22 easier to strip.

[0057] (Summary of Implementation Methods)

[0058] Next, the technical ideas grasped from the above-described embodiments are described by referring to the reference numerals in the embodiments. However, each symbol in the following description does not limit the constituent elements in the claims to the members specifically shown in the embodiments.

[0059] [1] A method for recovering copper from an enameled wire, comprising removing an insulator (22) from an enameled wire (2) having an insulator (22) around a conductor (21) composed of copper or a copper alloy, and recovering the copper or copper alloy constituting the conductor (21), the method comprising a stripping step of subjecting the enameled wire (2) to a compression process or a rolling process to peel the insulator (22) from the conductor (21), and a removal step of peeling and removing the insulator (22) stripped from the conductor (21).

[0060] [2] The method for recovering copper from an enameled wire according to [1], wherein the enameled wire (2) is a flat wire, and in the stripping step, the compression processing is performed by punching in the short axis direction of the enameled wire (2), and in the compression processing, the enameled wire (2) is processed in such a way that the thickness change rate in the short axis direction becomes 54.5% or more.

[0061] [3] The method for recovering copper from an enameled wire according to [1], wherein in the stripping step, the compression process is performed so that the rate of change in Vickers hardness becomes 105.5% or more.

[0062] [4] The method for recovering copper from an enameled wire according to [1], wherein, in the removal step, a slit (22a) is continuously cut along the length direction of the insulator (22) after the stripping step using a blade (41), and the insulator (22) divided by the slit (22a) is continuously stripped off, thereby removing the insulator (22).

[0063] (Note)

[0064] The embodiments of the present invention have been described above, but the embodiments described above do not limit the invention involved in the claims. In addition, it should be noted that all combinations of features described in the embodiments are not limited to the methods required for solving the problems of the invention. In addition, the present invention can be implemented by appropriately deforming within the scope of its main purpose.

Claims

1. A method for recovering copper from an enameled wire, comprising removing an insulator from an enameled wire having an insulator around a conductor made of copper or a copper alloy, and recovering the copper or copper alloy constituting the conductor, comprising: a stripping step of subjecting the enameled wire to a compression process or a rolling process to strip the insulator from the conductor, and In the removing step, the insulator separated from the conductor is peeled off and removed.

2. The method for recovering copper from enameled wire according to claim 1, wherein: The enameled wire is a flat wire, In the stripping step, the compression process is performed by pressing the enameled wire in a minor axis direction, and in the compression process, the enameled wire is processed so that a thickness change rate in the minor axis direction becomes 54.5% or more.

3. The method for recovering copper from enameled wire according to claim 1, wherein: In the peeling step, the compression process is performed so that the rate of change in Vickers hardness becomes 105.5% or more.

4. The method for recovering copper from enameled wire according to claim 1, wherein: In the removing step, slits are continuously cut along the longitudinal direction of the insulator after the stripping step using a knife blade, and the insulator divided by the slits is continuously stripped off to remove the insulator.

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