Method for treating metal-containing waste

Abstract

To provide a method of treating metal-containing waste that enables high-grade metal to be recovered in good yield.SOLUTION: The method of treating metal-containing waste includes: a heating step of heating metal-containing waste; a crushing step; a first sieving step of sieving the crushed material into oversize and undersize; a crushing step in which the undersize obtained in the first sieving step is crushed using a crusher equipped with a crushing mechanism having a vertical crushing surface; a magnetic separating step of separating waste rocks discharged from the crushing step into magnetized and non-magnetized materials; a second sieving step of separating the non-magnetized material obtained in the magnetic separating step into oversize and undersize; and a specific gravity-sorting step in which the oversize and undersize obtained in the second sieving step are processed in a specific gravity sorter equipped with a corrugated perforated plate having a plurality of concavities parallel to the oscillating direction or a perforated plate on which a plurality of slits or mesh with concavities parallel to the oscillating direction are placed, respectively.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a method for treating metal-containing waste. [Background technology]

[0002] Electronic and electrical equipment, such as automotive electrical components, home appliances, communication devices, and computers, are composed of numerous electronic devices, including cables, cable terminals, plugs, speakers, motors, printed circuit boards, relays, and button contacts. These components are often made of metal wire and foil, such as copper, brass, and aluminum. Stainless steel wire and carbon steel are also used for springs, fixing and connecting devices (screws, bands, stables, etc.), handles, decorations, and flexible tubes and support wires used to protect and reinforce optical fiber. Disposal of these various electronic devices generates large amounts of copper wire and other metal wires, as well as valuable metals such as copper and stainless steel. Therefore, efforts are being made to recover these metal wires and valuable metals for recycling.

[0003] For example, a method has been proposed in which waste electrical appliances containing at least ferrous metals, non-ferrous metals, coated copper wire, and plastics are crushed to a predetermined size, the ferrous metals are extracted from the crushed material by magnetic separation, the non-ferrous metals are extracted from the crushed material from which the ferrous metals have been extracted by magnetic separation by eddy current separation, and the crushed material from which the non-ferrous metals have been extracted by eddy current separation is vibrated in a substantially horizontal direction while being brought into contact with an airflow supplied from below to recover coated copper wire by gravity separation (Patent Document 1). Another method has also been proposed in which a roasted product obtained by roasting copper-containing scrap containing copper and either or both of gold and silver as valuable metals is used as an intermediate raw material, which is then sieved, and the under-sieved material is then subjected to electromagnetic induction separation to recover valuable metals (Patent Document 2). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2003-320311 [Patent Document 2] Japanese Patent Application Publication No. 2018-31062 Summary of the Invention [Problem to be solved by the invention]

[0005] However, the crushed waste electrical appliances described in Patent Document 1 contain copper wires of various sizes, including aluminum and other metals, making it difficult to selectively recover copper wires using simple gravity separation alone. Furthermore, the crushed products contain a large amount of finely divided resin, rubber, glass, and fibers, making it inevitable that other substances will be mixed in when recovering copper wires. On the other hand, the method described in Patent Document 2 only uses a sieve to recover copper. When applied to waste electrical appliances containing plastic, the glass fiber cloth and aluminum pieces used as the base material for printed circuit boards are also recovered as over-sieved residue, making it difficult to selectively recover only copper wires. Metal wires are naturally curved, U-shaped, and have other complex shapes, and are not uniform in shape. Therefore, when waste electrical appliances are crushed, the metal wires tend to entangle with each other, resulting in coarsening. Furthermore, problems such as the metal wires becoming entangled in the sieve meshes during sieving can occur, resulting in equipment blockages and forced shutdowns. An object of the present invention is to provide a method for treating metal-containing waste that can recover high-quality metals with high yield. [Means for solving the problem]

[0006] The inventors discovered that by heating and crushing metal-containing waste, then sieving the crushed material to separate it into oversized and undersized pieces, and then crushing the undersized pieces in a crusher equipped with a specific crushing mechanism and applying compressive stress, the curved or chunky copper wire contained in the undersized pieces can be adjusted to a straight and short length, and therefore copper wire can be recovered in high yield by processing it in a gravity separator equipped with a perforated plate having a predetermined shape.

[0007] That is, the present invention provides the following [1] to [6]. [1] A heating step of heating metal-containing waste; a crushing step of crushing the metal-containing waste after the heating step; a first sieving step of sieving the crushed metal-containing waste and separating it into oversized and undersized waste; a crushing step of crushing the undersize material obtained in the first sieve sorting step using a crusher equipped with a crushing mechanism having a crushing surface in a vertical direction; a magnetic separation step in which the waste stones discharged in the crushing step are magnetically separated into magnetic particles and non-magnetic particles; a second sieve sorting step in which the non-magnetic matter obtained in the magnetic sorting step is sieved to separate it into oversized matter and undersized matter; A gravity separation step in which the oversized and undersized particles obtained in the second sieve separation step are treated with a gravity separator equipped with a corrugated perforated plate having a plurality of recesses parallel to the rocking direction, or a perforated plate on which a mesh having a plurality of slits or recesses parallel to the rocking direction is placed. A method for treating metal-containing waste, comprising: [2] The processing method according to [1] above, wherein the grinding step uses one or more grinders selected from a roll mill, an edge runner mill, a centrifugal roller mill, and a disc mill. [3] The treatment method according to [1] or [2] above, wherein the heating step involves heating to 250 to 500°C. [4] The treatment method according to any one of [1] to [3] above, wherein a sieve with openings of 8 mm or more and 20 mm or less is used in the first sieve sorting step. [5] The processing method according to any one of [1] to [4], wherein a magnet having a surface magnetic flux density of 0.1 T or more is used in the magnetic separation step. [6] The treatment method according to any one of [1] to [5], wherein the mesh is one or more selected from plain tatami weave mesh, ton-cap mesh, tie rod mesh, and wedge wire mesh. [Effects of the Invention]

[0008] According to the present invention, high-quality metals can be recovered from metal-containing waste with a high yield. [Brief explanation of the drawings]

[0009] [Figure 1]1 is a flowchart showing one embodiment of the method for treating metal-containing waste of the present invention. [Figure 2] FIG. 2 is a diagram showing an example of a perforated plate that can be used in the gravity separation step according to the present invention. [Figure 3] FIG. 1 is a diagram showing an example of a mesh that can be used in the gravity separation step according to the present invention. [Figure 4] FIG. 2 is a schematic diagram showing an example of a gravity separation step according to the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0010] The method for treating metal-containing waste of the present invention will be described in detail below. Figure 1 shows a flowchart of a preferred embodiment of the method for treating metal-containing waste of the present invention. (Heating process) As shown in FIG. 1, in the method for treating metal-containing waste of the present invention, first, the metal-containing waste is subjected to a heating step in which it is heated. The heating in this process embrittles the resin components in the waste through a pyrolysis reaction in order to change the form of the waste into one that is easily destroyed by impact or compressive stress. Therefore, this process differs from so-called carbonization in that heating is carried out while leaving the hydrocarbon components of the resin components.

[0011] Metal-containing waste is not particularly limited as long as it contains metals, but an example of such waste is mixed waste. In this specification, "mixed waste" refers to waste that is discharged in a mixed state of metals and combustible materials such as plastics, and is difficult to separate by type. Specific examples of mixed waste include automobile shredder dust, shredder dust, and industrial waste plastics. Shredder dust is not particularly limited as long as it is generated by shredding industrial waste other than automobiles. Examples of industrial waste other than automobiles include home appliances, vending machines, office equipment, furniture, and building materials. Examples of industrial waste plastics include construction waste plastics, agricultural waste plastics, fishing waste plastics, marine waste plastics, and waste plastics with metal parts. These mixed wastes include, in addition to plastics, metal wires such as copper, brass, and aluminum, metal foils, springs, fixing and connecting jigs (screws, bands, stables, etc.), handles, ornaments, and flexible tubes and support wires made of stainless steel or carbon steel. However, they may also contain foreign matter such as paper, rubber, wood chips, glass chips, concrete chips, ceramic chips, slag, and rubble. One or more types of metal-containing waste may be used.

[0012] Heating of the metal-containing waste can be carried out in a furnace. Any type of heating furnace can be used as long as it can accommodate metal-containing waste and can be set to the desired temperature. Examples of such furnaces include fixed furnaces, stoker furnaces, rotary kilns, fluidized bed furnaces, vertical furnaces, and multi-tier furnaces.

[0013] A low-oxygen atmosphere is preferred for the atmosphere inside the heating furnace, from the viewpoint of retaining a large amount of heat and preserving its value as a fuel. For example, the use of an externally heated rotary kiln furnace makes it easy to perform heat treatment under low-oxygen conditions. Here, in this specification, a "low-oxygen atmosphere" refers to an atmosphere with an oxygen concentration lower than that of the atmosphere. Methods for reducing the oxygen content of the furnace atmosphere include, for example, filling the furnace with an inert gas such as nitrogen, saturated steam, or superheated steam, or by filling the furnace with gases generated primarily from the raw materials themselves (e.g., HO, CO, combustible gases such as lower hydrocarbons), combustion gases generated from combustion equipment, boiler steam, or the like.

[0014] The heating temperature is not particularly limited as long as it is a temperature at which the resin component is not carbonized, but from the viewpoint of promoting embrittlement of the waste, it is preferably 250 to 500°C, more preferably 275 to 475°C, and even more preferably 300 to 450°C. The heating time can be appropriately selected depending on the type and volume of the resin component contained in the waste, but is usually 30 to 120 minutes, preferably 60 to 90 minutes. The temperature during the heat treatment does not need to be constant, and for example, when a continuous rotary kiln furnace or stoker furnace is used, there may be a temperature gradient between the raw material input and output within the above temperature condition range.

[0015] The metal-containing waste after the heating process contains softened resin components, which can cause adhesion problems when transported to the crushing process described below. To prevent this, the metal-containing waste after the heating process may be cooled. A cooler can be used for cooling. There are no particular restrictions on the type of cooler, and existing coolers can be used. For example, a water-cooled jacket rotary cooler or a screw conveyor can be used.

[0016] (Crushing process) Next, as shown in Figure 1, a crushing process is carried out to crush the metal-containing waste after the heating process. This applies impact force to the embrittled metal-containing waste to break it into fine particles, peels off the resin adhering to the metal, and also peels off the multi-layered structures of electronic boards and fiber-reinforced plastics into single layers. Metal-containing waste can be crushed using a crusher, such as a jaw crusher, impact crusher, hammer crusher, roll crusher, or rotary crusher. The crushing process may be carried out two or more times. When the process is carried out two or more times, the same or different crushers may be used. A screen with the desired mesh size can be attached to the crusher for the purpose of adjusting particle size. If no screen is attached, the fixed teeth, rotating teeth, inner wall, etc. may be adjusted to the desired clearance.

[0017] (First sieving step) Next, as shown in Figure 1, the crushed metal-containing waste obtained in the crushing process is subjected to a first sieving process. This allows rubber pieces, metal pieces (mainly aluminum), large metal wires (mainly thick iron wires), and single-layer peeled substrates to be separated as oversized pieces. The undersized pieces are then subjected to the crushing process described below. The oversized pieces are primarily composed of iron, aluminum, and silicon, and can be used as a cement raw material as is. Depending on the type of raw material, a large amount of steel wire or stainless steel wire may be present on the oversized pieces. In this case, magnetically attached pieces may be collected using a magnetic separator. Copper and aluminum pieces present on the oversized pieces can also be collected using an eddy current separator and used as raw materials for non-ferrous metal refining.

[0018] A sieve separator can be used for sieving. There are no particular limitations on the type of sieve separator, and any of a vibration type, an in-plane motion type, a rotary type, and a fixed type may be used, but in order to prevent copper wires with peeled coating or wires from getting caught, it is preferable to use a grizzly type, finger type, or punched metal type mesh in the case of a vibration type, and it is preferable to use a disc screen, rotary screen, or trommel in the case of a rotary type.

[0019] The mesh size of the sieve is preferably 8 mm or more and 20 mm or less, more preferably 10 mm or more and 15 mm or less, from the viewpoint of recovering rubber pieces, metal pieces, metal wires, substrates, etc. as sieves.

[0020] (Crushing process) Next, as shown in Figure 1, the undersize waste separated in the first sieving process is crushed in a crushing process. In this process, a crusher equipped with a crushing mechanism with a vertical crushing surface is used to refine the combustible components contained in the undersize waste to a shape and size suitable for use as fuel. Furthermore, the copper wire, which has become curved or lumpy during the crushing process, is cut into short pieces by shearing force during crushing, while the shape is changed to a straight line by compressive force. Furthermore, compressive stress is applied to austenitic stainless steel to change its crystalline phase to martensite. The waste is then separated into finely granulated fine powder, which can be used as an alternative fuel to pulverized coal in cement kilns, and waste rock containing copper wire and stainless steel. The waste rock is then recovered from the bottom of the crusher.

[0021] Crushers are classified into (1) crushers with a crushing mechanism having a vertical crushing surface and (2) crushers with a crushing mechanism having a horizontal crushing surface. In this process, the crusher (1) described above is used. However, due to the vertical crushing surface, the material to be crushed, once compressed and sheared on the crushing surface, falls to the bottom of the crusher without remaining on the crushing surface and is then fed back to the crushing surface by a scraper plate located at the bottom. Therefore, copper wire that has become curved or lumpy is repeatedly subjected to shear and compression forces, which straightens it out and shortens it. Furthermore, austenitic stainless steel is repeatedly subjected to compressive stress, which transforms the crystalline phase into martensite. In contrast, using the crusher (2) described above does not achieve these effects, and furthermore, adhesion of combustible components occurs within the crusher, making continuous operation difficult.

[0022] In the above-mentioned (1) crusher, examples of the crushing mechanism having a crushing surface in the vertical direction include a mechanism for crushing between rollers, a mechanism for crushing between disks, and a mechanism for crushing between a roller and a pull ring. Crushers equipped with such crushing mechanisms include, but are not limited to, a roll mill, an edge runner mill, a centrifugal roller mill, and a disk mill. The grinding treatment may be carried out two or more times. When the grinding treatment is carried out two or more times, the same or different grinders may be used.

[0023] (Air classification process) The refined powder can be subjected to an air classification process to increase its fuel value. This allows for the separation of coarse particles, such as metal scraps and glass scraps, which are difficult to crush during milling. These coarse particles contain base metals such as iron, copper, and aluminum, as well as precious metals such as gold, silver, platinum, and palladium, which can be recovered by physical separation (e.g., magnetic separation, eddy current separation, gravity separation).

[0024] For air classification, an air classifier is used. The type of air classifier is not particularly limited as long as it is a dry type, and known air classifiers can be used. Examples include dry cyclones, rotor classifiers, and elbow jet classifiers. Furthermore, a similar air classification mechanism may be provided within the pulverizer described above in (1), and pulverization and classification of the pulverized material may be carried out continuously within the pulverizer.

[0025] For air classification, it is preferable to set classification conditions so that the average particle size (D50) of the fine particles used as a fuel substitute is approximately 500 μm or less. For example, conditions such as the air velocity inside the classifier and the rotation speed of the classifying rotor can be adjusted. Here, in this specification, the "average particle size (D50)" refers to the particle size (D50) corresponding to 50% of the cumulative distribution curve when the particle size distribution of a sample is prepared on a volume basis by the laser diffraction / scattering method in accordance with JIS R 1629. It should be noted that, for example, a Microtrac (manufactured by Nikkiso Co., Ltd.) can be used as a particle size distribution measuring device.

[0026] (Magnetic separation process) Next, as shown in Figure 1, the waste stone separated in the crushing process is subjected to a magnetic separation process. Among stainless steels, the commonly used austenitic stainless steel is not magnetic in its original form, but when compressive stress is applied in the crushing process, the crystalline phase changes to martensite, making it possible to recover almost all of the stainless steel along with iron and carbon steel as magnetic materials. Furthermore, removing the magnetic materials makes it possible to reduce the amount of non-magnetic materials to be processed in the next process.

[0027] For magnetic separation, a known magnetic separator can be used, and for example, any of a drum type, a pulley type, and a hanging type may be used, without any particular limitation. In magnetic sorting, for example, magnetic and non-magnetic materials are sorted using a magnetic sorting device having a magnetic drum in which a strong magnetic field is present, a belt conveyor (moving belt) wound around the magnetic drum, and a feeder that supplies samples onto the belt surface of the belt conveyor. In order to reduce the load on the gravity separation step described below, the magnetic separator preferably uses magnets with a surface magnetic flux density of 0.1 T or more, more preferably 0.3 T or more. There is no particular upper limit to the surface magnetic flux density, but it is usually 1.2 T, and preferably 1.0 T.

[0028] Alternatively, two or more magnetic separators may be arranged in series, each set to a different surface magnetic flux density, to separately recover metals with different magnetic properties. For example, by setting the surface magnetic flux density of the first separator to less than 0.3 T and the surface magnetic flux density of the second separator to 0.3 T or more, inherently ferromagnetic steels such as carbon steel and ferritic stainless steel may be recovered by the first separator, while austenitic stainless steel that has been partially magnetized by the crushing process may be recovered by the second separator.

[0029] (Second sieve sorting process) Next, as shown in Fig. 2, the non-magnetic materials separated by magnetic separation are subjected to a second sieve separation step, which can improve the separation efficiency in the gravity separation step described below. In this step, a sieve sorter can be used, as in the first sieve sorting step. The type of sieve sorter is not particularly limited, and any of a vibration type, an in-plane motion type, a rotary type, and a fixed type may be used, but from the viewpoint of preventing clogging with metal wires, it is preferable to use a punched metal screen, a grizzly feeder, a wedge wire screen, a louver screen, or a comb-tooth screen with respect to the shape of the sieve mesh.

[0030] From the viewpoint of improving the efficiency of sorting in the gravity sorting step, the mesh size of the sieve is preferably 2 mm or more and 10 mm or less, and more preferably 4 mm or more and 8 mm or less.

[0031] (Gravity sorting process) Next, as shown in Fig. 1, the oversized and undersized particles separated in the second sieve sorting step are subjected to a gravity sorting step in which they are treated in a gravity sorter equipped with a perforated plate having a predetermined shape. That is, the oversized and undersized particles are treated in a gravity sorter equipped with a perforated plate on which are mounted (i) a corrugated perforated plate having a plurality of recesses parallel to the rocking direction, or (ii) a mesh having a plurality of recesses parallel to the rocking direction, or (iii) a mesh having a plurality of slits parallel to the rocking direction.

[0032] The oversized and undersized fractions separated in the second sieve separation step contain aluminum and glass in addition to copper wire, and are therefore subjected to gravity separation. However, it has been found that when a flat, plain-woven mesh, commonly used in gravity separators, is used as the perforated plate, a certain amount of copper wire is scattered toward the light product side due to rolling. Therefore, in the present invention, by using a corrugated perforated plate (i) or a perforated plate with a mesh (ii) or (iii) mounted thereon in the direction of oscillation of the perforated plate, the copper wire can be oriented parallel to the direction of oscillation of the perforated plate. As a result, the inventors have found that the rolling of copper wire due to the oscillation of the perforated plate is suppressed, thereby suppressing scattering toward the light product side and significantly increasing the amount of copper wire recovered from the heavy product. Such an effect can only be achieved by combining the following two points: (1) using the crusher to repeatedly apply shearing force or compressive force to curved, U-shaped, or other complex-shaped copper wires to adjust them into straight lines and short lengths; and (2) subjecting the adjusted-shape copper wires to gravity separation using the corrugated perforated plate (i) or a perforated plate with a mesh (ii) or (iii). Therefore, even if a curved, U-shaped, or other complex-shaped copper wire is gravity separated using the corrugated perforated plate (i) or a perforated plate with a mesh (ii) or (iii), the copper wires will not be oriented parallel to the rocking direction of the perforated plate, and therefore the above-mentioned effect cannot be achieved.

[0033] An example of the corrugated perforated plate of the above-mentioned (i) is shown in Figure 2. The perforated plate shown in Figure 2 is a corrugated (V-shaped) perforated plate having a plurality of recesses parallel to the rocking direction of the perforated plate. An example of the mesh of the above-mentioned (ii) is shown in Figures 3(a) and (b). The mesh shown in Figure 3(a) is a plain tatami weave mesh, and the mesh shown in Figure 3(b) is a ton-cap mesh. An example of the mesh of the above-mentioned (iii) is shown in Figure 3(c). The perforated plate shown in Figure 3(c) is a wedge wire mesh. Alternatively, a tie rod mesh can be used.

[0034] Although known types of gravity separators can be used, a dry gravity separator is preferred, and an air table separator that separates materials by blowing air from below and using vibration is more preferred. An example of a preferred embodiment of this process is shown in Figure 4. Figure 4 shows the gravity separation process (i) using a corrugated perforated plate. As shown in Figure 4, by blowing air up from below the perforated plate while vibrating the inclined perforated plate, particles with a high specific gravity are separated from the materials to be sorted to the upper side of the perforated plate and particles with a low specific gravity are separated to the lower side of the perforated plate, and the copper wire can be oriented parallel to the direction of oscillation. This prevents the copper wire from rolling due to the oscillation of the perforated plate and prevents it from scattering to the light product side, allowing the copper wire to be recovered as a heavy product.

[0035] The corrugated perforated plate (i), and the mesh (ii) or (iii) and the perforated plate on which they are placed have holes for air passage, but the shape of the holes may be circular or rectangular and is not particularly limited. The hole size can be appropriately selected depending on the type of perforated plate and mesh used, but for example, when using a corrugated perforated plate, plain woven mesh, or toncap mesh, the mesh size in the direction perpendicular to the vibration direction is preferably 0.5 mm or less, more preferably 0.3 mm or less. When using a tie rod mesh, the mesh size in the short direction of the woven structure is preferably 0.5 mm or less, more preferably 0.3 mm or less. The lower limit of the hole diameter is not particularly limited as long as it allows air to pass through, but is usually 0.05 mm, and preferably 0.1 mm.

[0036] Of the copper particles contained in the sorted material, plate- or spherical-shaped particles can be collected on the upper side of the perforated plate. [Example]

[0037] The following examples will explain the present invention in more detail, but the present invention is not limited to the examples below.

[0038] Example 1 The metal-containing waste used was shredder dust containing household and commercial electrical appliances, furniture, etc., and was processed according to the flowchart shown in Figure 1. Specifically, the process is as follows: (Heating process) The shredder dust was fed into a heating furnace at a rate of 1000 kg / h and heated at 390° C. An externally heated rotary kiln was used as the heating furnace, and the recovery rate after the heating process was 750 kg / h. (cooling process) After the heating step, the shredder dust was cooled in a nitrogen atmosphere using an indirect rotary cooler and a cooling screw conveyor, and then transported to the crushing step using the screw conveyor. (Crushing process) The shredder dust after the cooling process was crushed using a hammer crusher equipped with a screen with an opening diameter of 30 mm. (First sieving step) The crushed shredder dust was sieved using a cylindrical vibrating sieve with 10 mm mesh, and the under-sieve material was collected. (Crushing process, air classification process) A centrifugal ring roller mill was used, and a forced vortex centrifugal classifier was installed inside the mill to continuously crush the under-sieve material and classify the crushed material inside the mill, separating it into refined powder discharged with the airflow and waste stone discharged from the bottom of the mill. (Magnetic separation process) The excreted stones were magnetically separated at a surface magnetic flux density of 0.3 T to separate them into magnetic and non-magnetic materials. (Second sieve sorting process) The non-magnetic material was screened using a cylindrical vibrating sieve with 10 mm mesh to separate it into oversized and undersized materials. (Gravity sorting process) The oversized and undersized materials were gravity separated using a left-right two-way air table having perforated plates as shown in Table 1, and separated into heavy products and light products. Table 1 shows the conditions used in the crushing step, magnetic separation step, second sieve separation step, and gravity separation step.

[0039] Example 2 The same operations as in Example 1 were carried out except that in the second sieve sorting step, the sieve mesh was changed to that shown in Table 1, and in the specific gravity sorting step, a perforated plate with a mesh shown in Table 1 placed on it was used.

[0040] Example 3 The same procedure as in Example 1 was carried out except that a perforated plate on which a mesh shown in Table 1 was placed was used in the gravity separation step.

[0041] Example 4 The same procedure as in Example 2 was carried out except that a perforated plate on which a mesh shown in Table 1 was placed was used in the gravity separation step.

[0042] Comparative Example 1 The same procedure as in Example 1 was carried out, except that the pulverization step was not carried out.

[0043] Comparative Example 2 The same procedure as in Example 2 was carried out, except that the pulverization step was not carried out.

[0044] Comparative Example 3 The same procedure as in Example 3 was carried out, except that the pulverization step was not carried out.

[0045] Comparative Example 4 The same procedure as in Example 4 was carried out, except that the pulverization step was not carried out.

[0046] Comparative Example 5 The same procedure as in Example 1 was carried out except that a perforated plate on which a mesh shown in Table 1 was placed was used in the gravity separation step.

[0047] Comparative Example 6 In the gravity separation step, the treatment was carried out in the same manner as in Example 1, except that a perforated plate on which a mesh shown in Table 1 was placed was used.

[0048] Comparative Example 7 The same procedure as in Example 1 was carried out except that a perforated plate on which a mesh shown in Table 1 was placed was used in the gravity separation step.

[0049] [Table 1]

[0050] In Examples 1 to 4 and Comparative Examples 1 to 7, the heavy products that passed through the sieve and the heavy products that passed through the sieve obtained in the gravity separation step were mixed, and the light products that passed through the sieve and the heavy products that passed through the sieve were mixed. The recovery ratios of the heavy products and the light products, the copper grade, and the recovery rate of copper obtained in the gravity separation step were then evaluated.

[0051] 〔evaluation〕 1. Copper grade analysis The copper grade was analyzed in accordance with JIS M 8121.

[0052] 2. Copper recovery rate The recovery rate was calculated using the following formula based on the input amount of raw material (shredder dust) and the value obtained by multiplying the total mass of heavy products and light products by the copper grade.

[0053] Recovery rate (%) = (A + B) / C × 100

[0054] (In the formula, A represents the value obtained by multiplying the mass of heavy products by the grade of copper contained in the heavy products, B represents the value obtained by multiplying the mass of light products by the grade of copper contained in the light products, and C represents the value obtained by multiplying the amount of raw material (shredder dust) input by the grade of copper contained in the raw material.)

[0055] [Table 2]

[0056] Table 2 shows that waste containing metal wire is heated and crushed, and then the crushed material is sieved to separate oversized and undersized material. The undersized material is then crushed in a crusher equipped with a specific crushing mechanism. This applies repeated shear and compression forces to curved, U-shaped, and other complex-shaped copper wires, allowing them to be adjusted into straight, short lengths. By processing this in a gravity separator equipped with a perforated plate or mesh of a specified shape, it is possible to recover copper wire with a high yield.

Claims

1. a heating step of heating the metal-containing waste; a crushing step of crushing the metal-containing waste after the heating step; a first sieving step of sieving the crushed metal-containing waste and separating it into oversized and undersized waste; a crushing step of crushing the undersize material obtained in the first sieve sorting step using a crusher equipped with a crushing mechanism having a crushing surface in a vertical direction; a magnetic separation step in which the waste stones discharged in the crushing step are magnetically separated into magnetic particles and non-magnetic particles; a second sieve sorting step in which the non-magnetic matter obtained in the magnetic sorting step is sieved to separate it into oversized matter and undersized matter; A gravity separation step in which the oversized and undersized particles obtained in the second sieve separation step are treated in a gravity separator equipped with a corrugated perforated plate having a plurality of recesses parallel to the rocking direction, or a perforated plate on which a mesh having a plurality of slits or recesses parallel to the rocking direction is placed. A method for treating metal-containing waste, comprising:

2. 2. The method according to claim 1, wherein the grinding step uses one or more grinders selected from a roll mill, an edge runner mill, a centrifugal roller mill, and a disc mill.

3. 3. The method according to claim 1, wherein the heating step involves heating to 250 to 500°C.

4. The treatment method according to any one of claims 1 to 3, wherein a sieve opening having a size of 8 mm or more and 20 mm or less is used in the first sieve sorting step.

5. 5. The processing method according to claim 1, wherein a magnet having a surface magnetic flux density of 0.1 T or more is used in the magnetic separation step.

6. The treatment method according to any one of claims 1 to 5, wherein the mesh is one or more selected from plain woven mesh, ton-cap mesh, tie rod mesh and wedge wire mesh.

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