Method for separating stainless steel and processing scrap electrical and electronic components

Abstract

Provided is: a separation method for stainless steel capable of efficiently separating stainless steel from electrical / electronic component scraps, in particular, crushed scraps obtained by subjecting electrical / electronic component scraps to a crushing processing; and a processing method for electrical / electronic component scraps. The separation method for stainless steel includes: a crushing step S2 for crushing electrical / electronic components; an air flow classification step S3 for classifying the crushed substance obtained in the crushing step by air flow and obtaining, as a heavy substance, excluded stones that include stainless steel; a coarse excluded stone sorting step S4 for sorting and collecting, from the excluded stones, coarse excluded stones having at least a predetermined size; and a first magnetic sorting step S6 for magnetically sorting coarse excluded stones and obtaining, as a magnetized substance, coarse excluded stones that include stainless steel, from the coarse excluded stones.

Description

[Technical Field]

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

[0002] In recent years, from the viewpoint of resource conservation, valuable metals have been recovered from scrap electric and electronic components of discarded home appliances, PCs, mobile phones, etc., and efficient recovery methods have been investigated. For example, Japanese Patent No. 6050222 (Patent Document 1) describes crushing copper-containing scrap electric and electronic components to a predetermined size and treating the crushed scrap electric and electronic components in a copper smelting furnace (flash furnace).

[0003] Furthermore, Japanese Patent No. 6228843 (Patent Document 2) describes a process for pulverizing copper-containing electrical and electronic component scraps, classifying the pulverized electrical and electronic component scraps using an air classifier, and recovering fine powder of the pulverized electrical and electronic component scraps. The recovered fine powder of the electrical and electronic component scraps is introduced into a smelting furnace for processing, and the unrecovered granular material is processed in an oxidation smelting furnace (converter). [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Patent No. 6050222 [Patent Document 2] Patent No. 6228843 Summary of the Invention [Problem to be solved by the invention]

[0005] As described in Patent Documents 1 and 2, in order to process scrap electrical and electronic components in a smelting furnace such as a flash smelting furnace, the scrap electrical and electronic components must be pulverized beforehand. However, the pulverized scrap electrical and electronic components contain organic matter such as resin, and these organic matter such as resin contain components such as carbon components that act as reducing agents in the flash smelting furnace. If these components cannot sufficiently react with the combustion air, problems such as over-reduction may occur.

[0006] On the other hand, the amount of scrap electrical and electronic components being processed has been increasing in recent years, and depending on the types of substances contained in the raw material electrical and electronic component scrap, larger amounts of substances that are undesirable for processing in the subsequent copper smelting process (smelting inhibitors) may be added to the furnace than before.

[0007] For example, in the case of a converter, if the amount of smelting inhibitors fed into the converter increases as the processing volume of electrical and electronic component scrap increases, impurities may not be completely separated in the converter, resulting in a high level of impurities when producing anodes for electrolysis. To improve this situation, it is desirable to remove smelting inhibitors from the electrical and electronic component scrap fed into the converter in advance. For example, pulverized scraps from electrical and electronic component scrap contain stainless steel, which contains smelting inhibitors such as nickel (Ni) and chromium (Cr). Therefore, it is desirable to efficiently remove stainless steel from the pulverized scraps before feeding them into the furnace.

[0008] In view of the above problems, the present disclosure provides a method for separating stainless steel and a method for treating scrap electrical and electronic components, which can efficiently separate stainless steel from scrap electrical and electronic components, particularly from pulverized scrap obtained by pulverizing scrap electrical and electronic components. [Means for solving the problem]

[0009] In order to solve the above problems, according to one aspect of the present disclosure, there is provided a method for separating stainless steel, including a crushing step for crushing electrical and electronic component scraps, an airflow classification step for classifying the crushed material obtained in the crushing step using an airflow to obtain waste stones containing stainless steel as heavy materials, a coarse waste stone sorting step for selecting and recovering coarse waste stones of a predetermined size or larger from the waste stones, and a first magnetic sorting step for magnetically sorting the coarse waste stones to obtain coarse waste stones containing stainless steel from the coarse waste stones as magnetic materials.

[0010] According to another aspect of the present disclosure, there is provided a method for treating scrap electric / electronic components including the above-mentioned stainless steel separation method, the method including a smelting furnace treatment step in which the finely pulverized material obtained in the air classification step is fed into a smelting furnace for treatment, and an oxidation smelting furnace treatment step in which at least a portion of the non-magnetic material obtained in the first magnetic separation step is fed into an oxidation smelting furnace for treatment. [Effects of the Invention]

[0011] According to the present disclosure, a method for separating stainless steel and a method for treating scrap electrical and electronic components can be provided that can efficiently separate stainless steel from scrap electrical and electronic components, particularly from pulverized scrap obtained by pulverizing scrap electrical and electronic components. [Brief explanation of the drawings]

[0012] [Figure 1] 1 is a flowchart showing an example of a stainless steel separation method according to an embodiment of the present invention. [Figure 2] 1 is a schematic diagram showing an example of the configuration of a vertical roller mill that can be used in a stainless steel separation method according to an embodiment of the present invention. [Figure 3] FIG. 1 is a schematic diagram illustrating an example of an eddy current separator. [Figure 4] FIG. 10 is a schematic diagram illustrating an example of an air table. DETAILED DESCRIPTION OF THE INVENTION

[0013] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The embodiments shown below are examples of devices and methods for embodying the technical concept of the present invention, and the technical concept of the present invention does not limit the structure, arrangement, etc. of the components to those described below.

[0014] (Stainless steel separation method) As shown in FIG. 1, the stainless steel separation method according to an embodiment of the present invention includes a crushing step S2 for crushing electrical and electronic component scraps, an airflow classification step S3 for classifying the crushed material obtained in the crushing step S2 using an airflow to obtain heavy waste stones containing stainless steel, a coarse waste stone sorting step S4 for selecting and recovering coarse waste stones of a predetermined size or larger from the waste stones, and a first magnetic sorting step S6 for magnetically separating the coarse waste stones of the predetermined size or larger to obtain coarse waste stones containing stainless steel from the coarse waste stones as magnetically attached materials.

[0015] Prior to the pulverization step S2, it is preferable to perform an incineration step S1 to incinerate at least a portion, preferably all, of the electrical and electronic component scraps. By performing the incineration process S1 prior to the pulverization step S2, at least a portion of the organic matter, such as resins, contained in the electrical and electronic component scraps can be removed by incineration, and the volume of material to be treated can be reduced. Furthermore, by removing at least a portion of the organic matter, such as resins, contained in the electrical and electronic component scraps by incineration, the occurrence of over-reduction problems due to carbon components contained in the electrical and electronic component scraps during treatment in a smelting furnace can be suppressed, and damage to the furnace bricks and jacket can be suppressed. Furthermore, the metals contained in the electrical and electronic component scraps become brittle, making them easier to pulverize in the subsequent pulverization step S2. Incineration removes volatile components from the electrical and electronic component scraps, thereby suppressing the intrusion of fluorine, chlorine, bromine, and other smelting inhibitors into the smelting furnace.

[0016] The specific conditions for the incineration step S1 are not particularly limited, but for example, the electrical and electronic component scraps are incinerated in a rotary kiln at about 550 to 1000°C and then cooled. The incinerated material after the incineration process may be further sieved, for example, with a sieve having openings of 10 to 20 mm.

[0017] In the crushing step S2, the scrap electrical and electronic components are crushed using a crusher. In this crushing process, the scrap electrical and electronic components are crushed to a particle size that allows unburned carbon to oxidize, Cu to react with S in the copper concentrate to form matte, and Fe to react with oxygen to form slag, before the scrap incinerated components sink to the bottom of the settler in the smelting furnace (e.g., flash furnace) or before they are discharged from the matte and slag discharge section.

[0018] Specifically, since the particle size of the concentrate charged into the smelting furnace is generally 10 to 150 μm in volumetric D50 (median diameter), it is preferable to pulverize, for example, electrical and electronic component scrap until the volumetric D50 is 150 μm or less. Alternatively, electrical and electronic component scrap may be pulverized until the volumetric D80 is 250 μm or less. Here, powders with a D50 of 150 μm or less and granules with a D80 of 250 μm or less are as fine as powder, and much finer than sand-like particles the size of sand grains. It is preferable to obtain a pulverized product by pulverizing until such fine particles like powder are obtained.

[0019] In the crushing step S2, the scrap electrical and electronic components may be mixed with silica ore that is charged into the smelting furnace together with the copper concentrate and crushed. Typically, in non-ferrous smelting furnaces, a solvent such as silica ore is charged into the smelting furnace together with the raw concentrate to improve the fluidity of the slag. However, when purchasing the solvent, it is often purchased in inexpensive lumps, and the solvent is often crushed in-house using a ball mill or similar. Therefore, if the solvent mill has sufficient capacity, the scrap electrical and electronic components can be mixed with the silica ore that is charged into the smelting furnace together with the copper concentrate and crushed, eliminating the cost of installing crushing equipment.

[0020] In the air classification process S3, the pulverized material obtained in the pulverization process S2 is separated into light and heavy materials by adjusting the air volume using the air classification effect, and the particle size of the pulverized electrical and electronic component scrap is controlled after pulverization. That is, in the air classification process S3, pulverized materials with a high specific gravity among the electrical and electronic component scraps cannot be carried upward by the air current unless they are finely pulverized, so this effect is used to carry finely pulverized materials below a certain size upward by the air current and collect them on the light material side, and pulverized materials with large particle sizes that could not be collected on the light material side are separated off to the heavy material side as waste.

[0021] The crushing step S2 and the air classification step S3 are preferably carried out simultaneously using a vertical roller mill as shown in Figure 2. In the process using a vertical roller mill, the electrical and electronic component scraps to be crushed are first fed to the center of a horizontally rotating table through a screw feeder. The table has recesses formed along its outer periphery. The electrical and electronic component scraps fed to the center of the table are moved toward the outer periphery of the table by centrifugal force. At this time, the electrical and electronic component scraps are crushed between the table and rollers (2 to 3 pieces) attached along the top surface of the recesses in the table.

[0022] The finely pulverized electrical and electronic component scraps move toward the periphery and are blown upward by an ascending air current (using atmospheric air) that flows from below. They are classified (airflow classification) and transported to the rotor above for collection. Meanwhile, the heavy pulverized materials fall downward, are crushed again by the roller and table, and are blown upward again, transported to the rotor, and collected. The lighter materials, with larger particle sizes or larger specific gravity, remain around the table. The heavy materials remaining around the table are called waste rock. This waste rock contains stainless steel, which, in addition to copper, contains nickel, chromium, and other smelting inhibitors. Separating the stainless steel from the waste rock allows for efficient recovery and effective use, while also reducing the amount of smelting inhibitors input into smelting processes such as converters and flash furnaces.

[0023] The pulverization step S2 and the air classification step S3 may be carried out separately in separate devices without using a vertical roller mill. Also, the pulverized material may be roughly crushed using a hammer crusher or the like before being treated in the vertical roller mill.

[0024] In the coarse waste stone sorting step S4, coarse waste stones of a predetermined size or larger are sorted out from the waste stones obtained in the air classifying step S3. The coarse waste stone sorting step S4 is not particularly limited as long as it is a method capable of sorting coarse waste stones into predetermined particle sizes, but it is preferable to include a sieving step in which waste stones of a predetermined size or larger are sieved out using a sieve.

[0025] Table 1 shows examples of chemical analysis values ​​of valuable metals contained in waste rock of each size when the waste rock was sieved using sieves with different mesh sizes. The component analysis of valuable metals was evaluated using inductively coupled plasma optical emission spectroscopy (ICP-OES). The size of each waste rock shown in Table 1 indicates the nominal mesh size W (mm) of the sieve based on JIS Z8801-1. The "%" listed as the unit for each element indicates the weight percentage of the target element in the waste rock of each size. As the concentrations of Au and Ag are low, they are evaluated in "g / t (equivalent to ppm)".

[0026] [Table 1]

[0027] As shown in Table 1, it has been newly discovered that the larger the size of the waste stone, the higher the content of Cr and Ni, which constitute stainless steel. In order to efficiently recover stainless steel, it is preferable to use a sieve with a nominal mesh size W of 3.35 mm or more, preferably 5.6 mm or more, and more preferably 9.5 mm or more, and to collect the waste stone that has been separated into the oversized material as coarse waste stone for stainless steel recovery. Here, for example, a size of more than 1.0 mm to 3.35 mm means waste stone that has been separated into the undersized material using a sieve with a nominal mesh size of 3.35 mm and that has been separated into the oversized material using a sieve with a nominal mesh size of 1.0 mm.

[0028] Furthermore, for the coarse waste stone sieved into the specified size groups shown in Table 1, we focused on five components - Cu, Fe, Al, SUS, and other metals - as the main metal elements contained in the coarse waste stone with particle sizes of over 5.6mm to 6.7mm, over 6.7mm to 9.5mm, over 9.5mm to 16.0mm, and over 16.0mm, and examined the composition ratio of SUS among them. Analysis of Cu, Fe, Al, SUS, and other metals was performed by hand sorting, and a comprehensive judgment was made using the magnetic properties of the raw material, the color, hardness, and weight of the polished surface when the raw material was polished with sandpaper as judgment criteria. As a result, it was found that the SUS ratio in coarse excreted stones with a particle size of between 5.6mm and 6.7mm was 11.4%, the SUS ratio in coarse excreted stones with a particle size of between 6.7mm and 9.5mm was 16.5%, the SUS ratio in coarse excreted stones with a particle size of between 9.5mm and 16.0mm was 17.2%, and the SUS ratio in coarse excreted stones with a particle size of over 16.0mm was approximately 27.4%, and that the larger the particle size, the higher the proportion of SUS in the composition.

[0029] From the above analysis results, it was found that in order to efficiently recover stainless steel from the coarse waste stone, it is effective to carry out a process of recovering coarse waste stone of a predetermined size or larger. Considering the efficiency of recovery of stainless steel and the ease of handling of the material to be sorted when using a sorting device such as a metal sorter described below, it is preferable to use a sieve with a nominal mesh size W of 5.6 mm or more, preferably 6.7 mm or more, and even 9.5 mm or more to collect waste stone of a size that can be sorted into the sieve-sized material. There is no particular upper limit to the size of the coarse waste stone, but it is typically 100 mm or less, or even 50 mm or less.

[0030] The sieving step is preferably performed after the air classification step S3. If the pulverized material after the pulverization step S2 is sieved as is without performing the air classification step S3, there is a risk that finely pulverized material adhering to the surface of the pulverized material with large particle sizes will be separated as sieved material. The finely pulverized material has a high copper and precious metal content, which causes a loss of valuable materials when recovering coarse waste stone containing stainless steel. By performing the air classification step S3 on the pulverized material after the pulverization step S2 and then selecting coarse waste stone of a predetermined size or larger in the sieving step, the finely pulverized material can be separated and recovered from the waste stone in the air classification step S3, thereby minimizing the amount of finely pulverized material adhering to the waste stone.

[0031] Next, in the first magnetic separation step S6, coarse waste stone containing stainless steel is obtained as magnetized material (magnetized material 2) from the coarse waste stone recovered in the coarse waste stone separation step S4. Most of the copper, aluminum, etc. constituting the coarse waste stone are separated into the non-magnetized material (non-magnetized material 2). In order to efficiently obtain the coarse waste stone containing stainless steel as magnetized material, it is preferable that in the first magnetic separation step, high-force magnetic separation is performed using, for example, a magnet pulley with a magnetic flux density of 3000 to 7000 G. This allows the coarse waste stone containing copper, aluminum, etc. to be separated into the non-magnetized material, while the coarse waste stone containing stainless steel can be selectively and efficiently recovered into the magnetized material.

[0032] It is more preferable to provide a second magnetic separation process S5 before the first magnetic separation process S6, in which the coarse waste stone is magnetically separated at a lower magnetic force than the first magnetic separation process S6, and the coarse waste stone containing iron is preliminarily removed as the magnetized material (magnetized material 1), thereby obtaining the non-magnetized material 1. Because iron is more easily attracted to magnets at a lower magnetic force than stainless steel, by performing the process at a lower magnetic force than the first magnetic separation process S6, it is possible to separate almost 100% of the coarse waste stone containing iron into the magnetized material. For example, it is preferable to perform low-magnetic separation in the second magnetic separation process using a suspended magnetic separator with a magnetic flux density of 200 to 600 G. By preliminarily removing the iron that would be magnetically attracted to the magnetized material in the second magnetic separation process S5, it is possible to prevent the coarse waste stone containing iron from being mixed in the first magnetic separation process S6, and to efficiently concentrate the coarse waste stone containing stainless steel into the magnetized material.

[0033] Next, in the eddy current sorting step S7, the magnetic materials obtained in the first magnetic sorting step S6 are eddy current sorted, and coarse waste stones containing stainless steel are obtained as non-repulsive materials from the magnetic materials obtained in the first magnetic sorting step S6. In the eddy current sorting step S7, for example, a sorting process can be performed using an eddy current sorter shown in FIG.

[0034] The eddy current separator includes, for example, a belt conveyor stretched between a tail pulley (not shown) and a head pulley, an eccentric magnet arranged inside the head pulley, a drive unit (not shown) for rotating the belt conveyor, a non-repulsive object collection unit arranged below the head pulley to collect non-repulsive objects that have flown up from the belt conveyor, a repulsive object collection unit arranged below the head pulley and forward of the non-repulsive object collection unit, and a damper arranged between the non-repulsive object collection unit and the repulsive object collection unit to separate the repulsive objects that have flown up from the non-repulsive objects. As shown in Figure 3, by using an eccentric eddy current separator in which the rotation axis of the pulley and the rotation axis of the eccentric magnet do not coincide, it is possible to reduce the entrapment of magnetic objects and efficiently separate coarse waste stone containing stainless steel.

[0035] In order to efficiently separate the coarse waste stones containing stainless steel from the magnetized materials 2 in the first magnetic separation step S6 into the non-repulsive material side, for example, the rotation speed of the rotor provided in the eddy current separator is set to 2000 to 2700 rpm, preferably 2250 to 2500 rpm, and the speed of the belt conveyor is set to 90 to 110 m / min, preferably 95 to 105 m / min. Also, in order to efficiently separate the coarse waste stones containing stainless steel into the non-repulsive material side, it is preferable to appropriately adjust the angle of the damper (angle θ in FIG. 3).

[0036] For example, the damper angle is preferably 55° or more, and more preferably 60° or more. On the other hand, if the damper angle is too large, there is a risk that the coarse stone waste containing copper, aluminum, etc. may be mixed into the non-repulsion object side. In this embodiment, the damper angle is preferably adjusted to about 50 to 70°, more preferably about 55 to 67°, and even more preferably about 58 to 65°. For example, by adjusting the damper angle to about 58 to 65°, 90% or more of the stainless steel in the coarse stone waste can be recovered on the non-repulsion object side.

[0037] Next, in the shape sorting step S8, the non-repulsive materials obtained in the eddy current sorting step S7 are shape-sorted, and a coarse waste stone containing stainless steel is obtained as a heavy product. In the example of FIG. 1, the shape sorting step S8 is performed after the eddy current sorting step S7. However, the order of processing may be changed, for example, by omitting the eddy current sorting step S7 and shape-sorting the magnetic materials obtained in the first magnetic sorting step S6, and obtaining a coarse waste stone containing stainless steel as a heavy product. Various sorting machines that utilize differences in specific gravity and shape of the target materials can be used as shape sorters, and the type is not particularly limited. For example, a rolling sorter that rolls the raw material for sorting can be typically used, and an air table, for example, is preferably used.

[0038] The coarse waste stones containing stainless steel separated in the first magnetic separation step S6 are often plate-shaped. On the other hand, other coarse waste stones containing copper, aluminum, etc. are often nearly spherical. Therefore, by using shape separation in the shape separation step S8, which utilizes differences in specific gravity and shape of the target materials, it is possible to more efficiently recover plate-shaped coarse waste stones containing stainless steel.

[0039] The shape sorter can be a single-axis air table sorter. For example, an air table sorter such as that shown in FIG. 4 can be used, although it is not limited to this. The air table sorter is installed to separate light products and heavy products by dry gravity separation, and is equipped with a vibrating table that is inclined at a predetermined angle and has multiple small vents (not shown) that allow air to pass through and vibrates in a predetermined direction, a holder (not shown) that holds the vibrating table, an upflow fan (not shown) that is installed below the holder and supplies air from the bottom to the top of the vibrating table, and a hopper (not shown) that feeds raw materials onto the vibrating table.

[0040] Plate-shaped coarse waste stones containing stainless steel fed onto the vibrating table are subjected to the force of the vibration of the vibrating table, which moves them towards the heavy product side, while light or spherical objects are strongly affected by the tilt and are collected on the light product side.

[0041] In the shape sorting step S8, to more efficiently recover the coarse waste stone containing stainless steel, the inclination angle of the vibrating table relative to the horizontal plane is preferably 10° or less, more preferably 9° or less, and even more preferably 8° or less. If the inclination angle is too small, the separation efficiency between the light product and the heavy product may not be improved. Therefore, the inclination angle of the vibrating table is preferably 5° or more, more preferably 6° or more, and even more preferably 7° or more. In this embodiment, for example, by adjusting the inclination angle of the vibrating table to 6 to 10°, 85% or more of the stainless steel can be distributed to the heavy product side of the coarse waste stone containing stainless steel, and in one embodiment, 92% or more can be distributed, thereby enabling efficient separation and recovery of the stainless steel. The vibration frequency of the vibrating table can be adjusted as appropriate. Typically, the vibration frequency is adjusted between 50 and 60 Hz, more preferably between 55 and 60 Hz. Air may also be supplied from a blow-up fan as needed.

[0042] Next, in the metal sorting step S9, the heavy product obtained in the shape sorting step S8 is sorted for metals using a metal sorter equipped with a sensor that can detect the strength of the metal reaction, and the coarse waste containing stainless steel is separated and recovered from the coarse waste containing copper and brass. By including the metal sorting step S9, the concentration of stainless steel in the separated and recovered material can be increased, further increasing the recovery efficiency of stainless steel.

[0043] The metal sorter used in the metal sorting process S9 requires sensing technology that can selectively detect stainless steel from mixed metals that include stainless steel, copper, brass, etc. Examples of metal sorters include metal sorters that use sensing technologies such as transmission X-ray (XRT), X-ray fluorescence (XRF), laser-induced plasma (LIBS), near-infrared (NIR), visible light (VIS), electromagnetic induction (ISS), and Raman spectroscopy.

[0044] In particular, in order to efficiently separate and recover coarse waste containing stainless steel from electrical and electronic component scrap according to this embodiment, it is preferable to use a metal sorter that uses electromagnetic induction (ISS) sensing technology. In such metal sorters that use electromagnetic induction (ISS) sensing technology, there are two types of detection methods for metal reactions: one that detects the presence or absence of metal, and one that detects the strength of the metal reaction. In this embodiment, it is more preferable to use a metal sorter that uses a detection method that detects the strength of the metal reaction in order to efficiently separate and sort waste containing stainless steel. This allows for efficient separation and recovery of stainless steel from coarse waste.

[0045] Although not limited to the following, the metal sorter may include, but is not limited to, a pair of pulleys (not shown) that hold the belt conveyor, a metal object recovery section and a non-metal object recovery section located below the belt conveyor, a detection section that is located on the underside of the belt conveyor and detects metal reactions in the raw materials by generating electromagnetic waves from a specified area on the underside of the belt conveyor, and a sorting device such as an air nozzle that sorts objects detected by the detection section into the metal object recovery section or the non-metal object recovery section.

[0046] In a metal sorter using electromagnetic induction (ISS) sensing technology, if the particle size of the raw material supplied to the metal sorter is too small, the sorting section cannot efficiently sort the raw material, which can result in reduced recovery efficiency. Therefore, it is preferable that the particle size of the coarse waste ore supplied to the metal sorter be set to be equal to or larger than the lower limit of particle size that can be sorted by the metal sorter. For example, by determining the size of the coarse waste ore in advance in the above-mentioned coarse waste ore sorting step S4 so that the particle size is equal to or larger than the lower limit of particle size that can be sorted by the metal sorter, the efficiency of metal sorting in the subsequent metal sorting step S9 can be improved. The specific condition for the lower limit of particle size of the coarse ore that can be sorted by the metal sorter is not particularly limited, but is, for example, about 5 mm, more preferably 8.0 mm or larger, and even more preferably 10.0 mm or larger.

[0047] Table 2 shows the SUS recovery rate (weight ratio) and concentration ratio when coarse waste rock of various particle sizes was sorted using a metal sorter with ISS-type sensing technology that detects the strength of metal reactions. The sizes of the coarse waste rock shown in Table 2 correspond to the nominal mesh size W (mm) of the sieve based on JIS Z8801-01. The concentration ratios shown in Table 2 represent the concentration ratio of SUS contained in the recovered coarse waste rock after sorting to the weight of SUS contained in the coarse waste rock before sorting. As shown in Table 2, when coarse waste rock with a particle size of 8.0 mm or larger is sorted into the oversized material using a sieve with a nominal mesh size W of over 8.0 mm, the SUS ratio in the recovered material after sorting is always over 90%. In other words, sorting coarse waste rock with a particle size of 8.0 mm or larger using a metal sorter can improve the SUS ratio in the recovered material after sorting.

[0048] [Table 2]

[0049] Table 3 shows the results of measuring the composition ratios and distribution rates of the major components of the coarse waste stone contained in the sieved material separated in the coarse waste stone separation process S4 (Fig. 1), the magnetic material 1 separated in the second magnetic separation process S5, the non-magnetic material 2 separated in the first magnetic separation process S6, the repulsed material separated in the eddy current separation process S7, and the heavy and light products separated in the shape separation process S8. In the coarse waste stone separation process S4, a sieve with a nominal mesh size of 5.6 mm was used. In the second magnetic separation process S5, a suspended magnetic separator was used to set the magnetic flux density to 400 G, and in the first magnetic separation process S6, a magnetic pulley was used to set the magnetic flux density to 7000 G. In the eddy current separation process S7, the damper angle was 62°, the rotor rotation speed was 2250 rpm, and the belt conveyor speed was 103 m / min. In the shape sorting process S8, the tilt angle was 8°, the table vibration frequency was 50 Hz, and the air speed was 0 mm / s. In Table 3, the composition ratios of stainless steel, copper / brass, iron, and aluminum were analyzed by manual sorting, based on a comprehensive assessment of the raw material's magnetic properties, the color, hardness, and weight of the polished surface after sanding the raw material. The composition ratio (%) indicates the weight ratio of the target material in each sorted product. The distribution ratio was calculated by setting each component of the sieved material as 100%, and then calculating the weight ratio of each component separated as magnetic material 1, non-magnetic material 2, repulsive material, light product, and heavy product. As shown in Table 3, more than 70% of the stainless steel in the sieved material can be recovered as heavy product in the shape sorting process S8. Furthermore, the majority of the heavy product separated in the shape sorting process S8 is crude waste containing stainless steel and crude waste containing copper or brass. This shows that by using a metal sorter that employs sensing technology that can selectively detect stainless steel from mixed metals to separate metals from heavy products, it is possible to increase the concentration of stainless steel in the separated and recovered material and further improve the stainless steel recovery efficiency.

[0050] [Table 3]

[0051] As described above, the stainless steel separation method according to the embodiment of the present invention enables efficient separation of stainless steel by recovering waste rock from crushed scraps obtained by crushing electrical and electronic component scraps and then performing the above-described process for separating and recovering stainless steel from the waste rock. This reduces the amount of smelting inhibitors, such as Ni and Cr, derived from stainless steel supplied to an oxidation smelting furnace such as a converter, and minimizes the impact of impurities in the oxidation smelting furnace, such as process inhibition. Since the separated and recovered crude waste rock containing stainless steel has had fine powders and other impurities removed in the airflow classification step S3, the impact of valuable metal recovery loss due to the adhesion of fine powder containing valuable metal components is reduced, and the waste rock is easier to handle than powdered material. Therefore, the stainless steel separation method according to the embodiment of the present invention allows for selective and efficient separation and recovery of stainless steel while suppressing a decrease in valuable metal recovery efficiency.

[0052] (Method of Disposing of Electrical and Electronic Parts Scrap) A method for treating scrap electrical and electronic components according to an embodiment of the present invention can include a smelting furnace treatment step in which the separated materials obtained in each step constituting the stainless steel separation method shown in Fig. 1 are fed into a smelting furnace such as a flash furnace for treatment, and an oxidation smelting furnace treatment step in which the separated materials are fed into an oxidation smelting furnace such as a converter for treatment. That is, the method for treating scrap electrical and electronic components according to an embodiment of the present invention includes a smelting furnace treatment step in which the finely pulverized material obtained in the air flow classification step S3 is fed into a smelting furnace for treatment, and an oxidation smelting furnace treatment step in which at least a portion of the non-magnetized materials 2 obtained in the first magnetic separation step S6 is fed into an oxidation smelting furnace for treatment.

[0053] The smelting furnace may be of any type, but may, for example, be comprised of a shaft, settler, and uptake (not shown), with a concentrate burner attached to the roof of the shaft. The finely pulverized material obtained in the air classification process S3, copper concentrate, a solvent (flux), and oxygen-enriched air are simultaneously blown into the concentrate burner, causing an instantaneous oxidation reaction. The finely pulverized material and other materials that have undergone the oxidation reaction are separated into matte and slag in the settler. The exhaust gas generated in the smelting furnace is sent to the uptake. The operating conditions of the smelting furnace in the smelting furnace treatment process are not particularly limited, and may be similar to known operating conditions, regardless of whether or not scrap electrical and electronic components are added, as long as they do not cause over-reduction.

[0054] The oxidation smelting furnace may be of any type, but may have, for example, a furnace opening at the top of a furnace body (not shown) and a tuyere at the bottom of the side of the furnace body. At least a portion of the non-magnetized materials 2 obtained in the first magnetic separation step S6, the matte separated in the smelting furnace, and a solvent (flux) are introduced into the furnace through the furnace opening. Oxygen-enriched air is then blown in through the tuyere to oxidize at least a portion of the non-magnetized materials 2 obtained in the first magnetic separation step S6. The operation of the oxidation smelting furnace in the oxidation smelting furnace treatment step may be carried out using a known operating method as long as it does not impair the original intended function of the oxidation smelting furnace.

[0055] 1, the coarse waste stone separated as magnetized material 1 in the second magnetic separation step S5, the coarse waste stone separated as non-magnetized material 2 in the first magnetic separation step S6, the coarse waste stone separated as repulsive material in the eddy current separation step S7, the coarse waste stone separated as light products in the shape separation step S8, and the coarse waste stone other than stainless steel separated as coarse waste stone not containing stainless steel in the metal separation step S9 are preferably fed into an oxidation smelting furnace. Alternatively, the magnetized material 1 in the second magnetic separation step S5 and the non-magnetized material 2 obtained in the first magnetic separation step S6 may be further subjected to metal separation using a metal sorter to separate the coarse waste stone containing stainless steel into the metal side, and this separated material may be fed into any of the eddy current separation step S7, shape separation step S8, and metal separation step S9 to improve the recovery efficiency of stainless steel.

[0056] According to the method for processing scrap electrical and electronic components of the embodiment of the present invention, it is possible to perform a process for removing stainless steel containing smelting inhibitors such as Ni and Cr from raw materials supplied to an oxidation smelting furnace such as a converter in advance, thereby suppressing various operational problems caused by the inclusion of smelting inhibitors in the oxidation smelting furnace treatment process and achieving efficient processing.In addition, by recovering waste rock containing stainless steel, the stainless steel can be reused.

[0057] Although the present invention has been described using the above embodiments, it is not limited to these embodiments, and the components can be modified and embodied without departing from the spirit of the invention. Furthermore, various inventions can be formed by appropriately combining multiple components disclosed in each embodiment. For example, some components may be omitted from all the components shown in the embodiments. Furthermore, components from different embodiments may be appropriately combined.

[0058] 1 is merely an example, and various other processing procedures can be adopted. For example, the eddy current sorting process S7, the shape sorting process S8, and the metal sorting process S9 may be omitted or their order may be reversed as appropriate. For example, the eddy current sorting process S7 and the shape sorting process S8 may be omitted. The order of the eddy current sorting process S7 and the magnetic sorting process (the first magnetic sorting process S6 and the second magnetic sorting process S5) may also be reversed. Furthermore, in the above-described embodiment, an example has been described in which a metal sorter using ISS-type sensing technology is used as the metal sorter, but it is also possible to use a metal sorter using other sensing technology, such as an X-ray sorter or a LIBS sorter. [Explanation of symbols]

[0059] S1: Incineration process S2…Crushing process S3: Air classification process S4…Rough stone sorting process S5: Second magnetic separation process S6: First magnetic separation process S7: Eddy current sorting process S8: Shape sorting process S9: Metal sorting process

Claims

1. a crushing step of crushing scrap electrical and electronic components; an air classification step in which the pulverized material obtained in the pulverization step is classified by airflow to obtain waste stones containing stainless steel as heavy materials; a coarse waste stone sorting step of sorting and recovering coarse waste stones of a predetermined size or larger from the waste stones by sieving; a first magnetic separation step of magnetically separating the coarse waste stone to obtain coarse waste stone containing stainless steel as a magnetically separated material from the coarse waste stone; A method for separating stainless steel, comprising:

2. a second magnetic separation step, which is performed before the first magnetic separation step, of magnetically separating the coarse waste stones at a magnetic force lower than that in the first magnetic separation step, and removing coarse waste stones containing iron from the coarse waste stones; an eddy current sorting step in which the magnetic material obtained in the first magnetic sorting step is sorted by eddy current to obtain coarse waste stones containing stainless steel as non-repulsive materials; The method for separating stainless steel according to claim 1, further comprising:

3. 2. The method for separating stainless steel according to claim 1, further comprising a shape sorting step of sorting the magnetic matter obtained in the first magnetic sorting step by shape to obtain crude waste containing stainless steel as a heavy product.

4. 3. The method for separating stainless steel according to claim 2, further comprising a shape sorting step of sorting the non-repulsive materials obtained in the eddy current sorting step by shape to obtain crude waste containing stainless steel as a heavy product.

5. 5. The method for separating stainless steel according to claim 3 or 4, further comprising a metal sorting step in which the heavy product obtained in the shape sorting step is sorted for metals using a metal sorter including a sensor capable of detecting the strength of the metal reaction, and the crude waste rock containing stainless steel is sorted and recovered as metal objects.

6. 6. The method for separating stainless steel according to claim 5, wherein the coarse waste stone sorting step selects and recovers coarse waste stones having a particle size equal to or larger than a lower limit of the particle size selectable by the metal sorter.

7. The method for separating stainless steel according to any one of claims 1 to 4, wherein the coarse waste stone sorting step includes a sieving step in which the sieving is performed using a sieve, and the sieving step includes obtaining, as the coarse waste stone, a sieved product obtained by sieving using a sieve having a nominal mesh size of 3.35 mm or more.

8. The method for separating stainless steel according to any one of claims 1 to 4, further comprising an incineration step of incinerating the electrical and electronic component scraps before the pulverization step.

9. A method for treating scrap electrical and electronic components, including the stainless steel separation method according to any one of claims 1 to 4, a smelting furnace treatment step in which the finely pulverized material obtained in the air classification step is charged into a smelting furnace and treated therein; an oxidation smelting furnace treatment step in which at least a portion of the non-magnetic materials obtained in the first magnetic separation step is charged into an oxidation smelting furnace for treatment; A method for disposing of scrap electrical and electronic components, including:

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