Recycling methods

Abstract

To provide a recycling method capable of recycling target metal from articles having fastening products by lowering a content concentration of impurities of iron, aluminum or the like.SOLUTION: A recycling method is for recycling metal from articles having fastening products (40, 50, 80) including metal components. The recycling method includes crushing steps (14, 34) of crushing at least a part of the metal components, and a screening step of screening crushed pieces including specific metal from crushed objects obtained in the crushing steps (14, 34).SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a recycling method for recycling metal from an article having a fastening product containing a metal part, or from a slider for a slide fastener, or from an article having a slider. [Background technology]

[0002] As technologies for effectively utilizing resources, for example, Japanese Patent Application Laid-Open No. 2018-140329 (Patent Document 1) and Japanese Patent Application Laid-Open No. 2019-089037 (Patent Document 2) describe clothing recycling devices and methods.

[0003] In the technology described in Patent Documents 1 and 2, clothing with decorative parts such as zippers is heated to embrittle the fabric part of the clothing, crushed to separate the fabric part from the decorative parts, and then sorted to separate low-specific-gravity materials including the fabric part from high-specific-gravity materials including metals. This makes it possible to thermally recycle the low-specific-gravity materials using them as fuel and to recycle valuable metals contained in the high-specific-gravity materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Publication No. 2018-140329 [Patent Document 2] Japanese Patent Application Publication No. 2019-089037 Summary of the Invention [Problem to be solved by the invention]

[0005] The technologies described in Patent Documents 1 and 2 enable the effective use of resources by recycling valuable metals from clothing that has decorative parts, etc. However, it is difficult to recycle the target metal at a high content. Furthermore, when considering, for example, the reduction of CO2 emissions in metal recycling, it is more effective to remelt the recycled metal and directly form the target member or part.

[0006] However, with the techniques described in Patent Documents 1 and 2, when parts such as sliders and rivets are used as fastening products, the recycled metal is likely to contain a large amount of impurities, making it difficult to remelt the recycled metal and stably obtain parts for fastening products.

[0007] Specifically, for example, stainless steel parts are sometimes used in sliders for slide fasteners. However, when metal (e.g., copper alloy) is recycled from sliders containing such stainless steel parts to form parts for fastening products, the Fe concentration in the metal forming the parts increases. As a result, when a fastening product containing a metal part with a high Fe concentration is attached to an article such as clothing, it is likely to cause a problem of the needle detector reacting when the article is passed through the needle detector.

[0008] For example, aluminum is often used in rivets, which are a type of fastening product. However, when metals such as copper alloys are recycled from parts containing rivets to form parts for fastening products, aluminum is also mixed into the recycled metal, which adversely affects the castability and processability of the parts.

[0009] Therefore, the present invention aims to provide a recycling method that can reduce the concentration of impurities such as iron and aluminum from articles such as clothing that have fastening products including sliders, rivets, etc., and recycle the target metal. [Means for solving the problem]

[0010] In order to achieve the above object, a recycling method according to a first embodiment provided by the present invention is a recycling method for recycling metals from an article having a fastening product including metal parts, the method including a crushing step of crushing at least some of the metal parts, and a sorting step of sorting out crushed pieces containing a specific metal from the crushed material obtained by the crushing step. The crushing step includes using a crusher having a plurality of chains to repeatedly collide the objects to be crushed with the chains and also to repeatedly collide the objects to be crushed with each other, thereby causing work hardening in the copper alloy metal parts. It is characterized by the following. The recycling method according to the first embodiment of the present invention preferably includes magnetic separation in the separation step.

[0011] The recycling method of the present invention preferably includes a heat treatment step, prior to the shredding step, of heat treating the article to separate the metal components of the fastening product from the fiber portion. In this case, the recycling method includes the steps of: By heating in an atmosphere of superheated steam, natural gas, or inert gas, Carbonizing the fiber portion to obtain carbide Carbonization treatment 、 The metals sorted in the sorting step are In the remelting process To redissolve and in the remelting step, the carbonized material obtained by the carbonization treatment is used as a reducing agent. It is preferred that the compound contains: In addition, in this recycling method, it is preferable to carry out sorting using a sieve after the heat treatment step and before the crushing step.

[0012] The second form of the recycling method provided by the present invention is a recycling method for recycling metals contained in sliders for slide fasteners or from articles having the sliders, and is characterized by including at least a crushing step for crushing the sliders, and a sorting step for sorting out crushed pieces containing specific metals from the crushed material obtained by the crushing step. The recycling method according to the second embodiment of the present invention preferably includes magnetic separation in the separation step.

[0013] In the recycling methods according to the first and second aspects of the present invention, the crushing step preferably includes repeatedly applying high-energy impacts to the metal parts or the sliders.

[0014] Furthermore, the recycling methods according to the first and second embodiments of the present invention preferably include recycling at least one of copper alloy, stainless steel, aluminum, and zinc as the metal. [Effects of the Invention]

[0015] According to the present invention, a recycling method can be provided that can reduce the concentration of impurities such as iron and aluminum from articles such as clothing that have fastening products including sliders, rivets, etc., and recycle the target metal. [Brief explanation of the drawings]

[0016] [Figure 1] FIG. 1 is a flow chart showing a recycling method according to a first embodiment of the present invention. [Figure 2] FIG. 1 is a schematic diagram illustrating a recycling method according to a first embodiment. [Figure 3] FIG. 2 is a schematic diagram showing a chain-type crusher used in the crushing step of the recycling method. [Figure 4] FIG. 4 is a flow chart showing a recycling method according to a second embodiment of the present invention. [Figure 5] FIG. 4 is a schematic diagram illustrating a recycling method according to a second embodiment. [Figure 6] FIG. 10 is a flow chart showing a recycling method according to a third embodiment of the present invention. [Figure 7] FIG. 10 is a schematic diagram illustrating a recycling method according to a third embodiment. DETAILED DESCRIPTION OF THE INVENTION

[0017] DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the present invention will now be described in detail with reference to the accompanying drawings. In the present invention, fastening products include slide fasteners having at least left and right fastener stringers and sliders, rivets, snap buttons (snap fasteners), buckles, cord stoppers, belt adjusters, loops, etc. Among such fastening products, fastening products containing metal parts (metal parts) or articles such as clothing to which such fastening products are attached are subject to metal recycling.

[0018] Furthermore, in the present invention, articles having fastening products and articles having sliders for slide fasteners include articles such as clothing (apparel) such as clothes and jeans, bags, daily necessities, and fabrics used therefor. For example, the following first embodiment describes the case of recycling metal from jeans to which slide fasteners and rivets having metal parts are attached, and the third embodiment describes the case of recycling metal from clothing fabric to which slide fasteners having metal parts are attached, but the present invention can also recycle metal from other articles (preferably textile products) to which fastening products containing metal parts are attached.

[0019] (First embodiment) Fig. 1 is a flow diagram showing the recycling method in the first embodiment, and Fig. 2 is a schematic diagram for explaining the recycling method in the first embodiment. In the first embodiment, a case will be described in which copper alloy, aluminum, and stainless steel are extracted as metals from jeans to which a slide fastener 40 having a metal part and a rivet 50 having a metal part are attached, and are reused.

[0020] First, before starting the recycling process, jeans having a slide fastener 40 and a plurality of rivets 50 attached thereto are prepared in advance as an article having a fastening product to be recycled (preparation 11 in FIG. 1).

[0021] In this case, as shown schematically in FIG. 2, the slide fastener 40 comprises a pair of left and right fastener stringers each having an element row formed by fastener elements 42 made of copper alloy attached to a fastener tape 41, a slider 43 slidably attached to the element row, and a first stop (top stop) 44 made of copper alloy and a second stop (bottom stop) 45 made of copper alloy provided adjacent to one end and the other end of the element row, respectively.

[0022] The slider 43 used in the slide fastener 40 has at least a slider body 43a and a pull tab 43b made of copper alloy, and a lock pin (stopping claw) 43c made of stainless steel used in the slider 43 locking mechanism (stopping mechanism).

[0023] The slider 43 is small in size and is formed by assembling the above-mentioned components together by subjecting at least some of them to plastic deformation (crimping). It has been difficult to crush such a slider 43 using a hammer-type crushing device, which is a commonly known crushing method. Furthermore, when crushing the slider 43 using a crushing device with rotating crushing blades, there is a problem in that the crushing blades are easily worn out.

[0024] Each rivet 50 has at least a rivet core 51 made of aluminum that has been subjected to plastic deformation processing, and a rivet cover 52 made of a copper alloy that covers a part of the rivet core 51. Furthermore, at least a part of the rivet 50 has been subjected to plastic deformation processing or the like, and is attached integrally to the denim fabric.

[0025] In addition, in the jeans preparation 11, the jeans may be divided into a plurality of parts, such as a part in which the slide fastener 40 is attached to the denim fabric, a part in which the rivet 50 is attached to the denim fabric, and a part made of only the denim fabric 60, by cutting the jeans, for example. Also, the jeans may be prepared in their original state without being cut.

[0026] Next, a heat treatment step (carbonization step) 12 is carried out in which the prepared jeans are subjected to a heat treatment (carbonization treatment in the first embodiment). In this heat treatment step 12, the prepared jeans are heated, for example, in an atmosphere of superheated steam at a temperature of 300°C to 600°C, to carbonize the fiber portions of the fastener tape 41 and the denim fabric 60. As a result, the tape shape of the fastener tape 41 and the shape of the denim fabric 60 are destroyed, the fiber portions are separated into small pieces, and each metal part, such as the fastener element 42, slider 43, first fastener 44, second fastener 45, and rivet 50, which are directly or indirectly attached to the fastener tape 41 and the denim fabric 60, can be cut away from the fiber portions and separated into pieces.

[0027] Furthermore, the carbonization step allows obtaining carbides 60a of the denim fabric 60 and 41a of the fastener tape 41 from the fiber portions of the denim fabric 60 and the fastener tape 41, respectively. These carbides 60a and 41a can be used as reducing agents in a remelting step 17 of the copper alloy, which will be described later.

[0028] In this way, by using the carbides 60a and 41a as reducing agents, copper alloy Since oxidation of the fastener can be suppressed, it is possible to improve the yield of each component of the fastening product (e.g., fastener element 42, slider body 43a, pull tab 43b, rivet cover portion 52, etc.) produced in the remelting process 17.

[0029] When carbonization is performed in the heat treatment step 12 as in the first embodiment, heating can be performed in an atmosphere of natural gas or an inert gas instead of superheated steam. Also, in the present invention, instead of carbonization, a combustion treatment for burning the fibrous portion of the denim fabric 60 or the like can be performed as the heat treatment step 12. By performing this combustion treatment, the fibrous portion of the denim fabric 60 or the like can be burned and removed, thereby making it possible to separate and disassemble the above-mentioned metal components.

[0030] After the heat treatment step 12 is completed, the metal parts 42, 43, 44, 45, 50 and the carbides 60a, 41a separated in the heat treatment step 12 are subjected to a sieving step (first sorting step) 13. This separates the large-sized carbides 60a, slider 43, rivet 50, etc. of the denim fabric 60 from the small-sized carbides 41a, fastener element 42, first fastener 44, second fastener 45, etc. of the fastener tape 41.

[0031] As a result, only the fastener element 42, the first stopper 44, and the second stopper 45, which are made of copper alloy, can be separated and recovered from metal parts such as the slider 43, which also contain other metals, and therefore copper alloys with low iron and aluminum contents can be stably recycled.

[0032] For example, in the case of the first embodiment, by remelting the fastener elements 42, the first fasteners 44, and the second fasteners 45 separated in the sieving process 13, it is possible to newly form the desired parts or components made of copper alloy, such as parts used in fastening products. As a result, it is possible to obtain effects such as the effective use of resources and the reduction of CO2 emissions. Note that in the present invention, it is also possible to omit the sieving process 13.

[0033] On the other hand, large-sized parts and portions of the denim fabric 60, such as the carbides 60a, sliders 43, and rivets 50, separated in the sieving sorting process 13, are sent to the shredding process 14, where they are shredded by a shredder 70. In the first embodiment, a chain-type shredder 70 (for example, Cross Flow Shredder (product name), manufactured by Sato Iron Works Co., Ltd.) shown in FIG. 3 is used as the shredder 70.

[0034] 3 includes a cylindrical crushing chamber 71, a chain fixing part 72 rotatably arranged on the bottom of the crushing chamber 71, a plurality of chains 73 having one end fixed to the chain fixing part 72, and a drive part (not shown) that rotates the chain fixing part 72. In this chain crushing machine 70, the objects to be crushed (objects to be crushed), such as carbide 60a of denim fabric 60, sliders 43, and rivets 50, are housed in the crushing chamber 71, and the crushing chamber 71 is kept sealed.By rotating the chain fixing part 72 at high speed, the objects to be crushed and the chain 73 are repeatedly collided, and the objects to be crushed are repeatedly collided with each other.

[0035] In the first embodiment, the slider body 43a and pull tab 43b of the slider 43 and the rivet cover 52 of the rivet 50, which are crushed in the crushing step 14, are made of, for example, a copper alloy. This copper alloy is known to be a metal with excellent ductility and relatively easy deformation. Therefore, in the first embodiment, in order to crush such copper alloy metal parts, metal parts such as the slider 43 and the rivet 50 are subjected to repeated high-energy collisions. For example, the high-energy collisions are performed by repeatedly colliding at high speeds or with heavy objects. This causes work hardening in the copper alloy metal parts, making them brittle, and as a result, the copper alloy metal parts can be crushed appropriately.

[0036] In the first embodiment, by performing the crushing step 14, the slider 43 is separated into the slider body 43a, the pull tab 43b, and the lock pin 43c, and each of the components can be crushed into smaller pieces. Similarly to the slider 43, the rivet 50 is also separated into the rivet core 51 and the rivet cover 52, and each of the components can be crushed into smaller pieces. For example, in the first embodiment, the crushing step 14 can crush each of the metal components into pieces of about 3 mm to 5 mm.

[0037] Therefore, the crushed material obtained after the crushing step 14 includes copper alloy crushed pieces obtained by crushing the slider body 43a, the pull tab 43b, and the rivet cover portion 52, stainless steel crushed pieces obtained by crushing the lock pin 43c, aluminum crushed pieces obtained by crushing the rivet core portion 51, and carbides 60a of the denim fabric 60.

[0038] In the first embodiment, the slider body 43a, pull tab 43b, lock pin 43c, rivet core 51, and rivet cover 52 are actually crushed into a plurality of small pieces as described above by performing crushing step 14, but in Fig. 2, in order to clearly show the features of the first embodiment, the crushed state of each part is shown in its original shape rather than in the state of the crushed pieces (the same applies to Figs. 5 and 7 described below). Furthermore, the crushing step 14 of the present invention is only required to be able to crush the slider 43 and rivet 50 and separate them into individual parts, and the processing conditions for crushing step 14 and the size of the crushed pieces obtained in crushing step 14 are not particularly limited.

[0039] The crushed material obtained in the crushing step 14 is then sent to a magnetic sorting step (second sorting step) 15. In this magnetic sorting step 15, stainless steel crushed pieces (crushed pieces of the lock pin 43c) are separated and collected from the crushed material using magnetic force.

[0040] More specifically, in the magnetic sorting process 15 of the first embodiment, a first magnetic sorting process is carried out in which magnetic metals such as iron pieces are sorted and removed by magnetic force, and a second magnetic sorting process is carried out in which a magnetic field stronger than that in the first magnetic sorting process is applied to sort and recover broken pieces of the stainless steel lock pin 43c, which is a weakly magnetic material.

[0041] First, by performing the first magnetic separation process using a general magnetic field, the risk of foreign matter such as iron pieces being mixed in when performing magnetic separation using a high magnetic field to recover stainless steel crushed fragments can be reduced. After that, by performing the second magnetic separation process using a high magnetic field on the crushed material that has been subjected to the first magnetic separation process, the stainless steel crushed fragments (crushed fragments of lock pin 43c) can be efficiently recovered and reused or sold.

[0042] On the other hand, the crushed material from which magnetic metals and stainless steel have been removed by the magnetic sorting process 15 contains copper alloy crushed pieces obtained by crushing the slider body 43a, pull tab 43b, and rivet cover portion 52, aluminum crushed pieces obtained by crushing the rivet core portion 51, and carbides 60a of the denim fabric 60, as shown in Figure 2.

[0043] After the magnetic sorting step 15, the remaining crushed material is subjected to a wet specific gravity sorting step (third sorting step) 16. This wet specific gravity sorting step 16 separates and recovers the copper alloy crushed fragments obtained by crushing the slider body 43a, pull tab 43b, and rivet cover portion 52, the aluminum crushed fragments obtained by crushing the rivet core portion 51, and the carbide 60a of the denim fabric 60. If any crushed fragments could not be separated in this wet specific gravity sorting step 16, these crushed fragments can be subjected to another wet specific gravity sorting using different sorting conditions, allowing the desired materials to be separated.

[0044] The aluminum fragments (fragments of rivet cores 51) recovered in the wet gravity separation process 16 can be reused or sold. The copper alloy fragments can be sent to the remelting process 17 and remelted to form new copper alloy parts or components, such as components used in fastening products. This results in effective resource utilization and reduced CO2 emissions, making a significant contribution to achieving the Sustainable Development Goals (SDGs). The carbide 60a can be used as a reducing agent in the copper alloy remelting process 17.

[0045] In the first embodiment, instead of the above-mentioned wet specific gravity separation process 16, it is also possible to use a separation method such as wind separation, air table separation, or heavy liquid separation to separate and recover the target metals from the crushed material obtained after the magnetic separation process 15.

[0046] According to the recycling method of the first embodiment described above, it is possible to stably recover metals such as stainless steel, aluminum, and copper alloy from jeans to which the slide fastener 40 and rivet 50 are attached. In particular, copper alloys have low concentrations of impurities such as stainless steel and aluminum, and high purity copper alloys can be recovered stably. For example, in the first embodiment, the Fe concentration and Al concentration in the recovered copper alloy can both be reduced to 500 ppm or less, preferably 300 ppm or less.

[0047] Therefore, for example, when a fastening product is manufactured using the recovered copper alloy, it is possible to prevent a needle detector from reacting to the copper alloy when an article such as clothing to which the fastening product is attached is passed through the needle detector, and it is also possible to prevent a decrease in the castability and workability of parts used in the fastening product due to aluminum in the copper alloy.

[0048] Furthermore, in the first embodiment, by carbonizing the fiber portion and recovering the carbides 60a, 41a, as described above, it becomes possible to use the carbides as a reducing agent in the copper alloy remelting step 17, thereby enabling more effective use of resources. In addition, there is also an effect of improving the yield of parts or components obtained from the remelting step 17.

[0049] In the first embodiment, for example, if the items to be recycled do not include rivets 50 or the like having aluminum parts, it is possible to omit the wet specific gravity separation step 16 for separating and recovering aluminum crushed fragments. In this case, the crushed material obtained after the magnetic separation step 15 contains only copper alloy crushed fragments, so that the copper alloy crushed fragments can be easily recovered and recycled.

[0050] (Second embodiment) Fig. 4 is a flow diagram showing the recycling method in the second embodiment. Fig. 5 is a schematic diagram for explaining the recycling method in the second embodiment. In the second embodiment, a case will be described in which only the slider 43 for the slide fastener is the object of recycling, and the copper alloy and stainless steel are removed from the slider 43 and reused.

[0051] First, a slider 43 to be recycled is prepared in advance (Preparation 21 in FIG. 4). This slider 43 is formed substantially similarly to the slider 43 included in the slide fastener 40 of the first embodiment described above. That is, the slider 43 of the second embodiment has at least a slider body 43a and a pull tab 43b made of a copper alloy, and a lock pin 43c made of stainless steel. In addition, at least a portion of the slider 43 has been subjected to plastic deformation processing (crimping processing) or the like when the parts were assembled.

[0052] Next, the prepared slider 43 is subjected to the crushing step 22. In this crushing step 22, crushing processing is performed by the crusher 70 shown in Fig. 3, as in the case of the first embodiment described above. By performing this crushing step 22, the slider 43 is separated into each component part, the slider body 43a, the pull tab 43b, and the lock pin 43c, and each component part can be crushed into smaller fragments.

[0053] The crushed material obtained by crushing the sliders 43 in the crushing step 22 is then sent to the magnetic sorting step 23. As in the first embodiment described above, this magnetic sorting step 23 performs a first magnetic sorting step in which magnetic metals are sorted and removed by magnetic force, and a second magnetic sorting step in which a magnetic field stronger than that in the first magnetic sorting step is applied to select and recover stainless steel crushed pieces. This allows the crushed pieces of stainless steel (crushed pieces of the lock pin 43c) to be efficiently collected and reused or sold.

[0054] Furthermore, the crushed material from which magnetic metals and stainless steel have been removed by the magnetic sorting step 23 contains only copper alloy crushed fragments obtained by crushing the slider body 43a and the pull tab 43b, as shown in Figure 5. This makes it easy to recover the copper alloy crushed fragments, which can then be sent to the remelting step 24 for remelting. This makes it possible to newly form the desired copper alloy parts or components, such as parts used in fastening products.

[0055] As described above, according to the recycling method of the second embodiment, even from the slider 43 alone, the stainless steel and copper alloy can be separated as metals and stably recovered.

[0056] (Third embodiment) Figure 6 shows the 3 FIG. 7 is a flow chart showing a recycling method in this embodiment. 3 1 is a schematic diagram illustrating a recycling method according to an embodiment of the present invention. In the third embodiment, a case will be described in which zinc, copper alloy, and stainless steel are extracted as metals from clothing to which a slide fastener 80 having metal parts is attached, and are reused.

[0057] First, before starting the recycling process, clothing to be recycled, to which slide fasteners 80 having metal parts are attached, is prepared in advance (preparation 31 in FIG. 6).

[0058] In this case, as shown schematically in FIG. 7, the slide fastener 80 has a pair of left and right fastener stringers each having an element row formed by fastener elements 82 made of copper alloy attached to a fastener tape 81, a slider 83 slidably attached to the element row, a stop (top stop) 84 made of copper alloy provided adjacent to one end of the element row, and a separable end stop 85 made of zinc provided adjacent to one end of the element row.

[0059] The slider 83 used in the slide fastener 80 has at least a slider body 83a and pull tab 83b made of zinc, a stainless steel lock pin 83c used in the locking mechanism of the slider 83, and a copper alloy cover portion 83d that covers part of the pull tab 83b and the lock pin 83c. The slider 83 is formed in a small size, and is formed by assembling the above-mentioned parts integrally by subjecting at least some of them to plastic deformation processing (crimping processing) or the like.

[0060] In this preparation 31, the garment (to be recycled) with the slide fastener 80 attached may be separated, for example by cutting, into parts in which the slide fastener 80 is attached to the garment fabric 61 and parts consisting only of the garment fabric 61. Alternatively, the garment may be prepared as is.

[0061] Next, the prepared garments are sent to a heat treatment step (carbonization step) 32 where they are subjected to a heat treatment (carbonization treatment). By carrying out the carbonization treatment in this heat treatment step 32, the fiber portions of the fastener tape 81 and the clothing fabric 61, etc. are carbonized and separated into small pieces, and each metal part, such as the fastener element 82, slider 83, stop 84, and separable end stop 85, can be separated from the fiber portions. In addition, the heat of this carbonization treatment melts the zinc slider body 83a, pull tab 83b, and separable end stop 85, and as the molten zinc cools, a zinc block 86 is formed in which the zinc and several parts are integrated. Furthermore, carbides 81a, 61a that can be used as a reducing agent in the remelting step can be obtained from the fiber portions, that is, the fastener tape 81 and the clothing fabric 61.

[0062] After the heat treatment step 32, the metal parts and carbides 81a, 61a obtained in the heat treatment step 32 are subjected to a sieving sorting step 33 to separate the large-sized carbides 61a and zinc lump 86 of the clothing fabric 61 from the small-sized carbides 81a of the fastener tape 81 that are not integrated with the zinc lump 86, the fastener elements 82, the stoppers 84, and the cover portion 83d of the slider 83 (note that FIG. 7 shows an example in which the cover portion 83d of the slider 83 is integrated with the zinc lump 86). This makes it possible to recover only the fastener elements 82, the stoppers 84, and the cover portion 83d made of the copper alloy, and as a result, it is possible to recycle the copper alloy with a low iron content. In the present invention, the screening step 33 can be omitted.

[0063] The large-sized parts and portions, such as the carbides 60a of the clothing fabric 61 and the zinc lumps 86, separated in the sieving sorting step 33 are then sent to the crushing step 34, where, as in the first embodiment described above, they are crushed by the crusher 70 shown in Fig. 3. By performing this crushing step 34, the carbides 61a of the clothing fabric 61 can be crushed into smaller pieces. Furthermore, the zinc lumps 86 are crushed to form small-sized zinc crushed pieces 87, and the metal parts and carbides integrated into the zinc lumps 86 are separated, and the separated metal parts and carbides can each be crushed into smaller pieces.

[0064] The crushed material obtained after this crushing process 34 includes zinc crushed fragments 87, stainless steel crushed fragments obtained by crushing the lock pin 83c, copper alloy crushed fragments obtained by crushing the fastener element 82 and cover portion 83d etc. that were integrated into the zinc block 86, and carbides 61a, 81a of the clothing fabric 61 and fastener tape 81.

[0065] The crushed material obtained in the crushing step 34 is then sent to the magnetic sorting step 35. As in the first embodiment described above, this magnetic sorting step 35 involves a first magnetic sorting step in which magnetic metals are selected and removed, and a second magnetic sorting step in which a stronger magnetic field than that in the first magnetic sorting step is applied to select and recover stainless steel fragments, which are weakly magnetic. This allows the stainless steel fragments (fragments of the lock pin 83c) to be efficiently recovered and reused or sold.

[0066] In addition, the crushed material from which magnetic metals and stainless steel have been removed by the magnetic sorting process 35 contains zinc crushed fragments 87, copper alloy crushed fragments obtained by crushing the fastener element 82, cover portion 83d, etc., and carbides (not shown), as shown in Figure 7.

[0067] Next, in the third embodiment, a classification step 36 is performed on the crushed material remaining after the magnetic separation step 35. By performing this classification step 36, the crushed pieces can be separated into multiple groups based on the size and shape of the crushed pieces. For example, in the classification step 36 of the third embodiment, the crushed material after the magnetic separation step 35 is sorted using a sieve to be classified into a first group 91 of large crushed pieces, a second group 92 of medium crushed pieces, and a third group 93 of small crushed pieces.

[0068] In this way, by dividing the crushed material into three stages according to the size and shape of the crushed fragments and matching the size and shape of the crushed fragments for each group, it becomes easier to separate zinc and copper alloy, which have a small difference in specific gravity, and the separation rate of zinc and copper alloy can be increased. For example, the first group 91, which is large in size, collects relatively large zinc crushed fragments 87 obtained by crushing zinc lump 86. Therefore, only the zinc crushed fragments 87 can be easily recovered and reused.

[0069] In addition, the second group 92, which is medium in size, collects zinc crushed fragments 87 obtained by crushing the zinc blocks 86, copper alloy crushed fragments obtained by crushing the fastener elements 82 and the cover portions 83d, etc., and carbides. In this case, by subjecting the crushed materials collected in the second group 92 to a sorting process such as the wet specific gravity sorting process 16 performed in the first embodiment described above, the zinc crushed fragments 87, copper alloy crushed fragments, and carbides can be separated and each can be recovered separately.

[0070] In addition, the recovered copper alloy fragments have a low concentration of impurities such as stainless steel and aluminum, and are high-purity copper alloys. Therefore, by sending them to a remelting process and remelting them, they can be used to form new parts or components for use in fastening products.

[0071] Since the smaller-sized third group 93 mainly collects zinc crushed fragments 87, it is possible to recover and reuse the zinc crushed fragments 87. Furthermore, if the crushed fragments collected in the third group 93 contain a large amount of copper alloy crushed fragments and / or carbides in addition to the zinc crushed fragments 87, then by performing an additional sorting process such as a wet specific gravity separation process, as in the case of the second group 92, the zinc crushed fragments 87, copper alloy crushed fragments, and carbides can be separated and recovered separately.

[0072] As described above, according to the recycling method of the third embodiment, it is possible to separate and stably recover metals such as stainless steel, zinc, and copper alloy from clothing to which slide fastener 80 having metal parts is attached. Also, by carbonizing the fiber portion and recovering carbides 61a, 81a, it becomes possible to use the carbides as a reducing agent in the remelting process of copper alloy, for example, thereby enabling more effective use of resources and also achieving the effect of improving the yield of parts or components obtained from the remelting process. [Example]

[0073] The present invention will be described in more detail below with reference to examples and comparative examples. As an example, the recycling method described in the first embodiment was used to separate and recover metals such as brass, which is a copper alloy, aluminum, and stainless steel from jeans fitted with slide fasteners 40 having metal parts and rivets 50 having metal parts. In this case, the slide fasteners 40 and rivets 50 fitted to the jeans to be recycled were formed as described in the first embodiment.

[0074] In the examples, the crushed pieces of copper alloy recovered after the wet gravity separation process 16 were dissolved and quantitatively analyzed by inductively coupled plasma optical emission spectroscopy (ICP-OES) to examine the Fe concentration in the copper alloy.

[0075] On the other hand, as a comparative example, the same jeans as those in the example were prepared, and the jeans were subjected to the heat treatment step (carbonization step) 12 described in the first embodiment, and the metal parts obtained after the heat treatment step 12 were collected. In addition, in the comparative example, all of the collected metal parts were dissolved and quantitatively analyzed by ICP-OES to examine the Fe concentration in the metal.

[0076] The Fe concentration in the copper alloy recovered in the Examples and the metal recovered in the Comparative Examples was examined. As a result, it was confirmed that the Fe concentration in the copper alloy recovered in the Examples was 180 ppm, which is lower than the Fe concentration specified in the JIS standard for copper alloys (C2100 to C2700). On the other hand, the Fe concentration in the metal recovered in the Comparative Examples was found to be a high value of 1000 ppm. [Explanation of symbols]

[0077] 11 Preparation 12 Heat treatment process (carbonization process) 13 Sorting process using a sieve (first sorting process) 14 Crushing process 15 Magnetic sorting process (second sorting process) 16 Wet specific gravity sorting process (third sorting process) 17 Remelting process 21 Preparation 22 Crushing process 23 Magnetic separation process 24 Remelting process 31 Preparation 32 Heat treatment process 33 Sorting process using sieves 34 Crushing process 35 Magnetic separation process 36 Classification process 40 Slide Fastener 41 Zipper Tape 41a Carbide 42 Fastener element 43 Slider 43a Slider body 43b Pull handle 43c Lock pin (stopping claw) 44 1st stop (upper stop) 45 2nd stop (bottom stop) 50 rivets 51 Rivet core 52 Rivet cover part 60 denim fabric 60a carbide 61 Clothing Fabrics 61a Carbide 70 Crusher 71 Crushing Room 72 Chain fixing part 73 Chain 80 Slide Fastener 81 Zipper Tape 81a Carbide 82 Fastener element 83 Slider 83a Slider body 83b Pull handle 83c lock pin 83d Cover part 84 Stop (upper stop) 85 Separable end stop 86 Zinc Block 87 Zinc fragments 91 Group 1 92 Group 2 93 Group 3

Claims

1. A method for recycling metal from an article having a fastening product (40, 50, 80) including a metal part, comprising: a crushing step (14, 34) of crushing at least some of the metal components; and A sorting step for sorting out crushed pieces containing specific metals from the crushed material obtained by the crushing step (14, 34). Including, The crushing step (14, 34) includes using a crusher (70) having a plurality of chains (73) to repeatedly collide the objects to be crushed with the chains (73) and also to repeatedly collide the objects to be crushed with each other, thereby causing work hardening in the copper alloy metal parts. A recycling method characterized by:

2. The sorting step is performed by magnetic sorting. The recycling method of claim 1, comprising:

3. a heat treatment step (12, 32) for heat treating the article to separate the metal components of the fastening product (40, 50, 80) from the fiber portion thereof, prior to the crushing step (14, 34); The recycling method according to claim 1 or 2, comprising:

4. In the heat treatment step (12, 32), a carbonization treatment is performed in which the fiber portion is carbonized to obtain a carbonized product by heating in an atmosphere of superheated steam, a natural gas atmosphere, or an inert gas atmosphere. Remelting the metals sorted in the sorting step in a remelting step; and In the remelting step, the carbonized material obtained by the carbonization treatment is used as a reducing agent. The recycling method according to claim 3, comprising:

5. After the heat treatment step (12, 32), before the crushing step (14, 34), the material is sorted by sieving. The recycling method according to claim 3 or 4, comprising:

6. A recycling method for recycling metal contained in a slider (43) for a slide fastener or from an article having the slider (43), comprising: a crushing step (22) of crushing at least the slider (43); and A sorting step for sorting out crushed pieces containing specific metals from the crushed material obtained in the crushing step (22). A recycling method comprising:

7. The sorting step is performed by magnetic sorting. The recycling method according to claim 6, comprising:

8. 8. The recycling method according to claim 1, wherein the crushing step (14, 22, 34) includes repeatedly applying high-energy impacts to the metal parts or the sliders (43).

9. 9. The recycling method according to claim 1, wherein the metal is at least one of copper alloy, stainless steel, aluminum, and zinc.

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