Disposal method for waste electrical and electronic components

Abstract

To provide a method for treating electric / electronic component scraps which can efficiently recover plastic scraps with a variable material from electric / electronic component scraps.SOLUTION: A method for treating electric / electronic component scraps includes a step of subjecting component scraps containing plastic generated in a sorting process of electric / electronic component scraps to specific-gravity sorting using salt water, and separating and recovering plastic scraps with a variable material.SELECTED DRAWING: Figure 1

Description

[Technical field]

[0001] The present invention relates to a method for treating scrap electrical and electronic components. [Background technology]

[0002] In recent years, from the perspective of resource conservation, recovery of valuable metals from discarded home appliances, PCs, mobile phones, and other scrap electrical and electronic components has become increasingly common, and efficient methods for recovering these metals have been studied and proposed.

[0003] For example, Japanese Patent Laid-Open Publication No. 9-78151 (Patent Document 1) describes a method for recycling valuable metals, which includes a step of charging scrap containing valuable metals, such as scrap electric and electronic parts, into a flash smelting furnace for smelting copper ore and recovering the valuable metals in the matte remaining in the furnace.

[0004] Japanese Patent Application Laid-Open No. 2018-123380 (Patent Document 2) describes a method for recovering valuable metals from recycled raw materials containing aluminum, in which the recycled raw materials are charged into a melting furnace in a copper smelting process, the aluminum is oxidized to become a component of the molten slag layer and removed from the system, the valuable metals are dissolved in the metal layer and matte layer, and the dissolved valuable metals are recovered. [Prior art documents] [Patent documents]

[0005] [Patent Document 1] Japanese Patent Application Publication No. 9-78151 [Patent Document 2] JP 2018-123380 A Summary of the Invention [Problem to be solved by the invention]

[0006] In the treatment using a copper smelting flash furnace as described in Patent Documents 1 and 2, as the amount of scrap electrical and electronic components processed increases, the carbon content contained in organic matter such as resins constituting the electrical and electronic component scrap increases, which may cause problems due to over-reduction in the smelting furnace. On the other hand, the amount of scrap electrical and electronic components processed has been increasing in recent years, so there is a demand for efficient treatment using a copper smelting flash furnace.

[0007] However, as the amount of scrap electrical and electronic components processed increases, depending on the type of substance contained in the scrap electrical and electronic components, a larger amount of substances that are undesirable for the subsequent copper smelting process (smelting inhibitors) will be added than before. If the amount of smelting inhibitors charged to the copper smelting process increases, a situation will arise where the amount of scrap electrical and electronic components that is added must be limited.

[0008] In order to efficiently input scrap electric and electronic parts into the smelting process and recover valuable metals, it is desirable to prepare a raw material that has a high concentration of valuable metals recovered in the smelting process while keeping the concentration of smelting inhibitors as low as possible. The inventors have studied various sorting methods, but since scrap electric and electronic parts are composed of various parts and materials with different specific gravities and shapes, it has been difficult to selectively and efficiently sort and recover valuable-containing plastics from scrap parts in which valuable metals and plastics are mixed.

[0009] In view of the above problems, the present disclosure provides a method for treating scrap electric and electronic components that can efficiently recover valuable-material-containing plastic scraps from scrap electric and electronic components. [Means for solving the problem]

[0010] In order to solve the above problems, one aspect of an embodiment of the present invention is a method for processing scrap electrical and electronic components, which includes a step of performing a specific gravity separation process using salt water on scrap electrical and electronic components containing plastic generated during a sorting process, and separating and recovering valuable plastic scraps. Effect of the Invention

[0011] According to the present disclosure, a method for treating scrap electric and electronic components can be provided that can efficiently recover valuable-material-containing plastic scraps from scrap electric and electronic components. [Brief description of the drawings]

[0012] [Figure 1] FIG. 1 is a flow chart showing a method for treating scrap electrical and electronic components according to an embodiment of the present invention. [Diagram 2] 1 is a flow diagram showing an overall flow of a sorting process for scrap electric and electronic components according to an embodiment of the present invention and an example of scrap components sorted in each sorting process. FIG. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0013] The following describes the embodiments of the present invention with reference to the drawings. The embodiments described below are merely examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention is not limited to the structures and arrangements of the components described below.

[0014] (Gravity separation process using salt water) A method for processing scrap electrical and electronic components according to an embodiment of the present invention includes the steps of subjecting scrap electrical and electronic components, including plastic, generated during the sorting process of scrap electrical and electronic components to a gravity separation process using salt water, and recovering valuable plastic scraps separated by this gravity separation process.

[0015] Electrical and electronic scrap refers to scraps of electronic and electrical equipment such as discarded home appliances, PCs, and mobile phones that have been crushed into appropriate sizes after collection. The crushing to obtain electrical and electronic scrap may be done by the processor himself, or crushed scraps purchased from the market may be used.

[0016] The crushing method is not limited to a specific device, and may be a shearing method or an impact method, but it is preferable to crush the parts without damaging their shape as much as possible. Therefore, devices that belong to the category of crushers intended for fine crushing are not included.

[0017] Typically, but not limited to, crushed scraps having a particle size of about 10 mm to 100 mm, more typically 10 mm to 70 mm, and further 15 mm to 60 mm are preferably used as the electric / electronic component scraps. The particle size of the electric / electronic component scraps can be evaluated, for example, by extracting several to several tens of randomly selected crushed scraps from the electric / electronic component scraps and measuring the average long and short diameters of each of them.

[0018] In the method for processing scrap electric and electronic components according to the embodiment of the present invention, the scrap electric and electronic components are subjected to various physical sorting processes such as air sorting, sieving, color sorting, and metal sorting, so that the concentration of valuable metals such as copper (Cu), gold (Au), and silver (Ag) is increased in the raw material to be used as the smelting raw material. On the other hand, smelting inhibitors such as bromine (Br), chlorine (Cl), lead (Pb), zinc (Zn), antimony (Sb), aluminum (Al), and chromium (Cr) contained in the scrap electric and electronic components and that may adversely affect the operation in the smelting process are reduced as much as possible by the physical sorting process.

[0019] Although not limited to the following process, for example, it is preferable to carry out a metal sorting process using a metal sorter as a sorting process for scrap electric and electronic components, and then carry out a specific gravity sorting process using salt water on the sorted materials sorted into non-metallic objects by the metal sorting process.

[0020] The materials separated into the non-metallic category during the metal separation process include scrap parts containing plastic (synthetic resin). In addition to scrap parts that are almost 100% plastic, scrap parts containing plastics include circuit boards, plastic scrap with ICs, and lump-type coated wire scrap that contain valuables such as copper, gold, and silver that can be recovered in the smelting process (hereinafter referred to as "plastic scrap with valuables").

[0021] However, this valuable-containing plastic scrap has a specific gravity and shape that are very similar to those of plastic scrap that does not contain valuables, making it difficult to separate it using typical gravity sorting processes such as wind sorting and air table sorting.

[0022] In particular, when circuit board scraps are taken as an example of plastic waste containing valuables, among electrical and electronic component scraps, there are circuit board scraps containing valuables such as copper in relatively large amounts. While it is desirable to collect such circuit board scraps containing valuables, it is difficult to selectively separate and collect only the circuit board scraps containing valuables, since the specific gravity and shape of the circuit board scraps containing valuables are similar to those of circuit board scraps not containing valuables. Similarly, when covered wire scraps (including connectors) are taken as an example of component scraps containing plastic, covered wire scraps are strongly curved, so that they are likely to be erroneously detected by the metal sensor of the metal sorter, and are mixed into the plastic collection side. Therefore, there are cases where the collection efficiency of covered wire scraps is not significantly improved.

[0023] According to the method for treating scrap electric / electronic parts according to the embodiment of the present invention, plastic-containing scrap parts generated during the sorting process of scrap electric / electronic parts are subjected to a specific gravity sorting process using salt water (hereinafter also referred to as "salt water separation"), which allows for the preferential separation and recovery of valuable plastic scraps from the plastic-containing scrap parts with high efficiency.

[0024] The saltwater used in saltwater separation is preferably as concentrated as possible. Specifically, it is preferable to use saltwater of a saturated concentration from the viewpoint of processing efficiency. The saltwater concentration can be, for example, about 25 to 26 mass% salinity. In saltwater separation, plastic-containing scrap parts are put into a tank filled with saltwater of a saturated concentration, and separated into floating matter and sediment by utilizing the difference in specific gravity. Plastic scraps with valuables are separated into the sediment side, and plastic scraps without valuables or plastic scraps with very low concentrations of valuables are separated into the floating matter side.

[0025] The plastic waste separated on the floating side is sent outside the treatment system. Since this plastic waste contains smelting inhibitors such as Cl and Br, by discharging it outside the treatment system of the smelting process, the amount of smelting inhibitors brought into the smelting process can be reduced.

[0026] The saltwater separation can be carried out in multiple stages. For example, as shown in Fig. 1, a first process can be performed using saltwater of a saturated concentration to carry out a first density separation process (first saltwater separation), and a second process can be performed using saltwater with a lower saltwater concentration than that of the first process to carry out a second density separation process (second saltwater separation) on the floating matter separated in the first process.

[0027] In the first treatment, valuable plastic waste is separated on the sediment side. In the second treatment, which treats the first saltwater separation water after separating valuable plastic waste, saltwater with a salt concentration lower than that in the first treatment, for example, 10 to 20 mass %, is used for saltwater separation, and plastic waste containing AS resin, acrylic resin (PMMA), polyamide resin (PA66), etc. is separated on the sediment side, and plastic waste containing polyethylene (PE), polypropylene (PP), ABS resin, polystyrene (PS), etc. is separated on the floating matter side. In order to efficiently separate these plastic wastes, it is preferable to use saltwater with a salt concentration of 10 to 20 mass %, more preferably about 13 to 16 mass %, in the second treatment. It is needless to say that the saltwater concentration can be appropriately adjusted according to the composition and specific gravity of the raw material.

[0028] By carrying out the first process, the substrate scraps, coated wire scraps, etc. can be separated into the sediment side, and the other plastic scraps can be separated into the floating side, so that when the other plastic scraps are used as raw materials in the recycling process, the content of smelting inhibitors such as chlorine carried into the recycling process can be reduced. This makes it possible to operate the recycling process more stably.

[0029] In addition, the plastic scraps such as AS resin, PMMA, PA66, etc., separated on the sediment side in the second process have high calories and can be sent to a recycling process as a plastic raw material for thermal chemical recycling. On the other hand, the plastic scraps such as PE, PP, ABS resin, PS, etc., separated on the floating side in the second process can be used as a recycling raw material, or can be used as a raw material to be sent to a smelting process equipped with a flash smelting furnace, or can be processed in a melting furnace to form matte and slag.

[0030] The separated wastewater from the first process contains high concentrations of valuable metals such as copper, gold, and silver. By supplying this wastewater as raw material to the smelting process, the recovery efficiency of valuable metals in the smelting process can be improved.

[0031] Here, when saltwater separation is performed in multiple stages, it is preferable to perform saltwater separation under conditions such that the saltwater concentration in the second treatment in the latter stage is lower than that in the first treatment. Since the floating matter obtained in the saltwater separation in the first treatment is used in the second treatment, by performing saltwater separation under conditions such that the saltwater concentration in the second treatment is lower than that in the first treatment, it becomes easier to adjust and manage the saltwater concentration in the second treatment.

[0032] However, the salt water concentration conditions for salt water separation are not limited to the above examples, and it is of course possible to carry out salt water separation under conditions where the salt water concentration in the second treatment is higher than that in the first treatment, if necessary. In addition, it is of course possible to carry out salt water separation in two or more stages, taking into account the specific gravities of the various types of plastic waste contained in the raw material.

[0033] (Method of Disposal of Scrap Electrical and Electronic Components) An example of a method for treating scrap electric and electronic components according to an embodiment of the present invention is shown in Fig. 2. The method for treating scrap electric and electronic components according to an embodiment of the present invention includes at least a step of treating scrap electric and electronic components by at least two stages of wind sorting (S2, S4) and a step of sorting board scraps by a metal sorting step (S6) using a metal sorter, and the salt water separation treatment can be performed on the sorted material sorted into the non-metallic object side in the metal sorting step (S6).

[0034] According to the method for processing scrap electrical and electronic components of an embodiment of the present invention, in the initial stage of physical sorting, air sorting is first performed in two stages (S2, S4). This makes it possible to reduce loss of valuable metals compared to the case where magnetic sorting is performed in the initial stage, and to sort and process a large amount of scrap electrical and electronic components at once while concentrating more valuable metals.

[0035] Then, by combining the two-stage wind sorting with a time-consuming sorting process (S6) using a metal sorter, it is possible to increase the amount of scrap electric and electronic parts being processed while removing smelting inhibitors and efficiently recovering valuable metals. Furthermore, by carrying out saltwater separation on the sorted material sorted into the non-metallic side in the metal sorting step (S6), it is possible to recover all valuable metals contained in the scrap parts on the non-metallic side.

[0036] In one embodiment, the scrap electric / electronic components input as raw material are sorted while maintaining a certain size and shape (for example, particle size of about 10 to 70 mm) without being crushed or shredded. This makes it possible to increase the amount of scrap electric / electronic components that can be processed per unit time. Furthermore, compared to the case where the scrap electric / electronic components are granulated or powdered by crushing and pulverization, the scrap electric / electronic components can be more easily handled as raw material, are easier to transport, and the overall processing efficiency can be improved.

[0037] Although the electric / electronic component scrap according to the embodiment of the present invention is not limited to the following, in one embodiment, the electric / electronic component scrap can be classified into lump copper wire scrap, powder, film, linear copper wire scrap, circuit board scrap, metal pieces, copper wire scrap, capacitors, IC chips, scrap iron (Fe), aluminum (Al) scrap, stainless steel (SUS) scrap, rubbers, synthetic resins including casings, and other scraps.

[0038] In this embodiment, scrap parts containing 90% or more by weight of the substance to be classified in the scrap parts are called "single scrap" and scrap other than single scrap parts containing a mixture of multiple substances are called "composite scrap". In this embodiment, raw material containing 60% or more, or even 70% or more of single scrap parts in the electric / electronic scrap parts is used as the raw material to be processed in the pre-sorting step S1, so that scrap parts containing the desired valuable materials can be sorted efficiently and accurately while removing smelting inhibitors from the system.

[0039] In a more specific embodiment, the method for processing scrap electric and electronic components according to an embodiment of the present invention includes a pre-sorting process (S1) for removing lump wire scrap from the scrap electric and electronic components, an air sorting process (S2) for air sorting the scrap electric and electronic components after the pre-sorting process and transferring powder-like and film-like scrap to the lighter material side and removing it, a sieving process (S3) for sieving the heavy materials obtained in the air sorting process and removing linear (long) wire scrap, a second-stage air sorting process (S4), a color sorting process (S5) for removing circuit board scrap containing valuable metals such as copper from the scrap electric and electronic components after the removal of the linear wire scrap using a color sorter, and a metal sorting process (S6) for further removing circuit board scrap containing valuable metals such as copper from the scrap electric and electronic components after the color sorting process using a metal sorter.

[0040] By providing a sieving process (S3) between the first stage wind sorting process (S2) and the second stage wind sorting process (S4), wire scraps contained in the electric and electronic component scraps can be removed. In the sieving process, it is preferable to use a sieving machine having a slit-shaped sieve. In the sieving process (S3), powdery matter can be removed in addition to wire scraps by sieving. The powdery matter and wire scraps after sieving can be sent to a smelting process via an incineration pretreatment process, so that valuable metals in the component scraps can be recovered more efficiently. In addition, by performing a color sorting process (S5) after the wind sorting process (S4), the metal content ratio of the processing object sent to the metal sorting process (S6) can be reduced, so that the sorting efficiency in the metal sorting process (S6) can be increased.

[0041] The heavy materials obtained in the second wind sorting step (S4) may contain some substrates to be processed in the copper smelting step. Therefore, by further classifying the heavy materials obtained in the second wind sorting step (S4) using the salt water separation process according to this embodiment, or a combination of magnetic separation, eddy current separation, color sorting, manual sorting, robotic, and other processes, the substrates to be processed in the copper smelting step can be separated and sent to the smelting step, thereby increasing the recovery efficiency of valuable metals.

[0042] For example, the heavy objects obtained in the second stage wind sorting process (S4) are sent to the magnetic sorting process (S8) via the pre-sorting process (S7). In the magnetic sorting process (S8), raw materials containing iron are removed from the heavy objects as raw materials not required for the smelting process. After the magnetic sorting process (S8), an eddy current sorting process (S9) is performed, and further, a pre-sorting process (S10) is performed to remove scraps containing aluminum, synthetic resins (plastics), and SUS, and the remaining substrate scraps are sent to the smelting process.

[0043] In the method for processing scrap electric and electronic components according to the embodiment of the present invention, a salt water separation process can be performed on the selected processing material sorted out as non-metallic objects in the metal sorting process (S6), which allows efficient and rapid processing of smelting raw materials containing valuable metals that can be processed in the smelting process, or raw materials outside the smelting system that do not contain precious metals and contain any of iron, aluminum, stainless steel, and synthetic resin, from the scrap electric and electronic components.

[0044] In addition, the method for processing scrap electric and electronic components according to the embodiment of the present invention does not necessarily require crushing and pulverization as performed in conventional wet gravity separation processes, and the sorting process is performed while maintaining the shape of the raw materials, making it easy to handle the raw materials and allowing a large amount of scrap electric and electronic components to be processed. Furthermore, by using the salt water separation process, it is possible to sort and process the scrap electric and electronic components more efficiently than when manual sorting is applied, and it is possible to mechanically process a larger amount of scrap electric and electronic components.

[0045] Furthermore, the method for processing scrap electric and electronic components according to this embodiment can be used in combination with each of the sorting processes (S1 to S10) as necessary. Furthermore, it is also preferable to perform image recognition processing on the raw materials sorted as external raw materials in the pre-sorting process (S7), magnetic sorting process (S8), eddy current sorting process (S9), and pre-sorting process (S10) and perform sorting processing to extract objects using a sorting device equipped with a robot hand. For example, aluminum scraps extracted after the eddy current sorting process (S9) include parts scraps with substrates containing valuable materials attached to the aluminum scraps. By further performing sorting processing using the salt water separation process according to this embodiment on the objects sorted as external raw materials in each of the sorting processes (S7 to S10), the amount of valuable materials mixed into the external raw materials can be reduced, and the recovery efficiency of valuable materials can be further improved.

[0046] (Smelting process) The method for processing scrap electric and electronic components according to the embodiment of the present invention further includes a smelting step for smelting the processing raw material containing valuable metals that have been sorted out in each of the sorting steps (S1 to S10).

[0047] When recovering copper as a valuable metal, smelting is performed using a smelting furnace. The smelting process includes, for example, a process of incinerating scrap electric and electronic components, a process of crushing and sieving the incinerated material, and a process of smelting the crushed and sieved material into copper. Depending on the processing capacity of the smelting process, the process of incinerating scrap electric and electronic components may be omitted.

[0048] In the smelting process, the process of crushing and sieving the scrap electric and electronic components can be performed by any method as long as it is a process that can shape the scrap electric and electronic components into a size suitable for smelting. By performing the physical separation process shown in Figure 2 before the incineration process and the crushing and sieving process in the smelting process, valuable metals can be recovered more efficiently while efficiently sending raw materials containing any of the following smelting inhibitors, iron, aluminum, stainless steel, and synthetic resin, out of the system.

[0049] Although not limited to the following, a copper smelting process using a flash smelting furnace can be suitably used as the smelting process according to the present embodiment. In the copper smelting process using the flash smelting furnace, for example, copper concentrate, a solvent, and scrap electrical and electronic components are charged from the ceiling of the shaft of a flash smelting furnace. The charged concentrate and scrap are melted in the shaft of the flash smelting furnace, and separated into matte containing, for example, 50 to 68% copper and slag floating above the matte in the settler of the flash smelting furnace. Valuable metals such as copper, gold, and silver in the scrap electrical and electronic components are absorbed into the matte retained in the flash smelting furnace, and the valuable metals can be recovered from the scrap electrical and electronic components.

[0050] In copper smelting, in order to produce copper and recover as much precious metal as possible, it is important to input as much scrap electrical and electronic parts as possible that contain valuable metals such as copper, gold, and silver. On the other hand, scrap electrical and electronic parts contain substances that affect the quality of products and by-products in copper smelting and / or smelting inhibitors that affect the copper smelting process. For example, if a large amount of substances containing elements such as Sb and Ni are input into the smelting furnace, the quality of the electrolytic copper obtained by copper smelting may decrease.

[0051] In non-ferrous metal smelting processes such as copper smelting, sulfuric acid is produced from sulfur dioxide generated by the oxidation of concentrates, but if hydrocarbons are mixed with the sulfuric acid, the sulfuric acid produced may become discolored. Sources of hydrocarbon contamination include synthetic resins such as plastics, and depending on the composition of the scrap electrical and electronic parts brought to copper smelting, such synthetic resins may be present in large amounts. Synthetic resins may cause sudden combustion and smoke leakage in the smelting furnace, as well as equipment deterioration due to localized heating.

[0052] Furthermore, if Al, Fe, etc. are present in a smelting furnace at a certain concentration or higher, it may change the slag composition in the copper smelting process, for example, and affect the loss of valuable metals to the slag, so-called slag loss. Also, if halogen elements such as Cl, Br, F, etc. are contained in large amounts in the electrical and electronic scrap fed into the smelting furnace, they may cause corrosion of the exhaust gas treatment equipment in the copper smelting process and deterioration of the sulfuric acid catalyst. The problem of contamination with such smelting inhibitors becomes more apparent as the amount of electrical and electronic scrap processed increases, resulting in a problem of a burden on the smelting process.

[0053] According to the method for treating scrap electric and electronic components according to the embodiment of the present invention, a salt water separation process is provided prior to the smelting process, as shown in Fig. 1. This makes it possible to minimize the proportion of smelting inhibitors brought into the smelting process, increase the amount of scrap electric and electronic components that can be treated, and increase the proportion of scrap electric and electronic components that contain copper and valuable metals, thereby enabling efficient recovery of copper and valuable metals.

[0054] Although the present invention has been described by the above embodiment, the description and drawings forming a part of this disclosure should not be understood as limiting the present invention. In other words, the present disclosure is not limited to the above embodiment, and the components can be modified and embodied without departing from the spirit of the present disclosure. EXAMPLES

[0055] Examples of the present invention will be described below together with comparative examples, which are provided for a better understanding of the present invention and its advantages, and are not intended to limit the invention.

[0056] In the metal separation process S6 of electric and electronic component scraps shown in Fig. 2, two-stage saltwater separation treatment was performed on the plastic-containing component scraps separated into the non-metallic material side. In the first saltwater separation treatment, saltwater separation was performed using 26% by mass salt water as the salt water, and the plastic scraps with valuables were transferred to the 26% sediment side, obtaining a 26% sediment and a 26% floating material. In the second saltwater separation treatment, saltwater separation was performed using 15% by mass salt water as the salt water on the 26% floating material, obtaining a 15% floating material and a 15% sediment. Table 1 shows the average weight ratios of various metals distributed to the 15% floating material, 15% sediment, and 26% floating material when similar tests were performed on nine types of electric and electronic component scraps from different sources.

[0057] [Table 1]

[0058] As shown in Table 1, by transferring 26% of the valuable plastic waste to the sediment side, it is possible to efficiently recover valuable metals such as copper, gold, and silver from the sorted material that was separated into non-metallic materials in the metal sorting process. In addition, the bromine and chlorine content in the 15% floating material was low, and by separating the salt water, it was possible to separate 40% or more of bromine and 10% or more of chlorine into the 15% sediment side, which shows that smelting inhibitors can be efficiently sent outside the smelting process system. [Explanation of symbols]

[0059] S1 Pre-sorting process S2 Wind sorting process S3 Sieving process S4 Wind sorting process S5 Color sorting process S6 Metal sorting process S7 Pre-sorting process S8 Magnetic separation process S9 Eddy current sorting process S10 Pre-sorting process

Claims

1. The waste electrical and electronic parts, including plastics, are subjected to a gravity separation process using saturated salt water, and valuable plastic waste is separated and collected in the sediment. A method for treating scrap electrical and electronic components, comprising the step of feeding the valuable-containing plastic scraps separated into the sediment side by the gravity separation process using saturated salt water into a melting furnace for copper smelting.

2. Before the gravity separation treatment using the salt water, a metal separation treatment using a metal sorter is performed; 2. The method for treating scrap electric and electronic parts according to claim 1, further comprising the step of subjecting the non-metallic substances separated out in the metal separating process to a gravity separation process using the salt water.

3. 3. The method for treating scrap electric and electronic parts according to claim 1, wherein the valuables-containing plastic scraps include circuit boards and coated wire scraps.

4. A first process for performing a first specific gravity separation process using salt water of a saturated concentration; a second process in which a second gravity separation process is performed on the floating matter separated in the first process using salt water having a salt water concentration lower than that of the first process; The method for treating scrap electric and electronic parts according to any one of claims 1 to 3, further comprising the steps of:

5. The method for treating scrap electric and electronic parts according to any one of claims 1 to 4, wherein the valuable-containing plastic scrap contains at least any one of copper, gold, and silver.

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