JP2022140937A - Treatment method for waste - Google Patents

Abstract

To provide an efficient treatment method for waste containing metal wires, capable of preventing troubles caused by the metal wires.SOLUTION: A treatment method for waste includes: a heating step of heating waste containing metal wires; a crushing step of crushing the waste after the heating; a first sieving and sorting step of separating the crushed waste into an upper sieve group and a lower sieve group through a comb type inclined sieve with a sieve mesh of less than 20 mm; a second sieving and sorting step of sieving and sorting, through a punching metal or a comb type sieve, the lower sieve group after the first sieving and sorting into two grain groups or three or more grain groups; and a physical sorting step of separating each grain group after the second sieving and sorting into metals and non-metals by performing one or more physical sorts, selected from specific gravity sorting, eddy current sorting, shape sorting, color sorting and electromagnetic induction sorting, for each grain group after the second sieving and sorting.SELECTED DRAWING: None

Description

The present invention relates to a waste disposal method.

Wires such as metal wires and coated copper wires are used as components of electronic and electric equipment such as electric parts of automobiles, home electric appliances, communication equipment, and computers. Since a large amount of linear materials are generated as a result of disposal of such various electronic devices, the linear materials are collected and recycled. For example, since copper wire is highly valuable, as a method of recovering copper wire from coated copper wire, a method of separating copper nuggets from coated copper wires after cutting the coated copper wire has been adopted. However, although nugget sorting is particularly effective in recovering thick metal wires with a diameter of 1 mm or more, thin metal wires are not recovered because it is difficult to separate them from the coating.

Therefore, as a method of sorting and recovering fine copper wires and plastics from waste home appliances with high precision, waste home appliances are crushed into a predetermined size, and the crushed matter is sorted by wind to extract the foamed resin. Ferrous metals are extracted from the extracted crushed material by magnetic separation, non-ferrous metals are extracted from the crushed material from which the ferrous metals have been extracted by eddy current separation, coated copper wires are separated from the crushed material from which the non-ferrous metals have been extracted, and coated copper A method has been proposed in which small metal clumps are extracted from the crushed material from which the wires are separated by wind sorting, fine copper wires are extracted from the crushed metal clumps from which the metal clumps have been removed, using a vibrating sieve, and finally the plastic is recovered (Patent document 1). In addition, a filter having a plurality of rods extending at intervals from each other to collect light objects including at least linear objects and plate-like objects by wind-sorting crushed electronic and electric equipment parts. A method has been proposed in which a linear material is sieved under a sieve by placing it on a filter of a vibrating sieve machine and vibrating the filter (Patent Document 2).

Japanese Patent Application Laid-Open No. 2003-320311 WO2019/151350

However, since the shape of the metal wire is not uniform such as curved, U-shaped, spiral, etc., when the waste containing the metal wire is crushed, the metal wires become entangled with each other, resulting in coarsening. Problems such as entanglement of the metal wire in the sieve meshes occur, which necessitates clogging of the equipment and suspension of operation. Thus, it is difficult to efficiently and stably treat waste containing metal wires.
An object of the present invention is to suppress troubles caused by metal wires and to provide an efficient disposal method for waste containing metal wires.

The present inventors heat and embrittle waste containing metal wires, crush the embrittled waste, sift the crushed waste with a specific sieve having a specific sieve mesh, Furthermore, by sieving with a specific sieve and then physically sorting, it is possible to suppress the entanglement of the metal wires, the accompanying coarsening, and the entanglement of the metal wires with the sieve mesh, so that the troubles caused by the metal wires are eliminated. It was found that waste containing metal wires could be treated efficiently and stably. Furthermore, by intentionally binding the metal wires contained in the waste before crushing the embrittled waste, troubles caused by the metal wires in the subsequent treatment are further suppressed. We have found that waste containing metal wires can be treated efficiently and stably.

That is, the present invention provides the following [1] to [5].
[1] A heating step of heating a waste material containing a metal wire;
A crushing step of crushing the waste after heating;
A first sieving step of separating the crushed waste into upper and lower sieves using a comb-teeth type inclined sieve with a screen mesh of less than 20 mm;
A second sieving step of sieving the under-sieves obtained in the first sieving into two grain groups or three or more grain groups with a punching metal or a comb-tooth sieve;
Each particle group obtained in the second sieve sorting is subjected to one or more physical sorting selected from specific gravity sorting, eddy current sorting, shape sorting, color sorting and electromagnetic induction sorting, and physical separation into metal and non-metal A method of treating waste, including a sorting process.
[2] The method for treating waste according to [1] above, which comprises a binding step for binding together the metal wires in the heated waste after the heating step and before the crushing step.
[3] The method for treating waste according to [1] or [2] above, wherein in the heating step, the waste containing the metal wire is heated to 250 to 500°C.
[4] The method for treating waste according to any one of [1] to [3] above, wherein the comb tooth type inclined sieve used in the first sieving step has a sieve mesh of 8 mm or more and 15 mm or less. .
[5] The method for treating waste according to any one of [1] to [4] above, wherein the punching metal or comb-tooth sieve used in the second sieving step has a sieve mesh of 10 mm or less.

According to the present invention, troubles caused by metal wires can be suppressed, so that wastes containing metal wires can be treated efficiently and stably.

It is a flow chart which shows one embodiment of the manufacturing method of the present invention. 4 is a flow chart showing another embodiment of the manufacturing method of the present invention; 4 is a flow chart showing another embodiment of the manufacturing method of the present invention;

The waste disposal method of the present invention will be described below.

(First embodiment)
FIG. 1 shows a flow chart of the waste disposal method according to this embodiment.
In the processing method according to the present embodiment, as shown in FIG. 1, first, a heating step is performed to heat waste containing metal wires. This process aims to embrittle the waste without incinerating it.

The waste used in this step is not particularly limited as long as it contains a metal wire, but examples include shredder dust from automobiles, and shredder dust from household and commercial electrical appliances and furniture. These wastes include electronic parts such as cables, cable terminals, plugs, speakers, motors, printed circuit boards, relays, and button contacts. , paper, wood chips, etc. may be included. These electronic parts include, for example, metal wires such as copper, brass, and aluminum, metal foils, springs, fixing/connecting jigs (screws, bands, stables, etc.), handles, ornaments, stainless steel or carbon steel Flexible tubes and support wires are used.

Heat treatment of waste is usually performed in a heating furnace.
The heating furnace is not particularly limited as long as the waste can be accommodated and the desired temperature can be set. Moreover, the shape of the heating furnace is not particularly limited, and may be, for example, a cylindrical shape, a rectangular cross-sectional shape, or any other appropriate shape. A conveyor may be installed in the heating furnace for conveying the waste from the waste supply port to the waste discharge port.

Among them, it is preferable to use an externally heated rotary kiln as the heating furnace and heat in a low-oxygen atmosphere from the viewpoint of fixing a large amount of heat of the organic component contained in the waste to the solid fuel and increasing its value. As a method for making the atmosphere in the furnace low in oxygen, for example, the inside of the furnace may be filled with nitrogen or water vapor to make the atmosphere low in oxygen, or gases (H ₂ O, CO ₂ , Combustible gas, etc.) may be filled in the furnace to reduce oxygen.

The heating temperature is preferably 250 to 500°C, more preferably 275 to 475°C, and even more preferably 300 to 450°C, from the viewpoint of promoting embrittlement of the waste.
The heating time can be appropriately selected according to the type and volume of the resin contained in the waste, but is usually 30 to 120 minutes, preferably 60 to 90 minutes.

Next, as shown in FIG. 1, a crushing step is performed to crush the heated waste. As a result, it is possible to finely granulate the lumps of resin contained in the waste and peel off the resin adhering to the metal. It should be noted that, in this step, metal wire clumps contained in the waste are hardly pulverized.
A crushing machine can be used for the crushing process. The crusher is not particularly limited as long as it can crush waste, and for example, jaw crushers, impact crushers, hammer crushers, roll crushers, and rotary crushers can be appropriately selected. The crusher can be equipped with a screen with a desired sieve mesh for the purpose of particle size adjustment. If a screen is not installed, the fixed teeth, rotating teeth, inner wall, etc. can be adjusted to the desired clearance. good.

As for the size of the waste after crushing, the particle diameter D90 is usually 3 mm or more, preferably 5 mm or more. Here, the "particle size D90" as used herein refers to the cumulative volume-based particle size distribution measured in accordance with JIS R 1629 "Method for measuring particle size distribution of fine ceramic raw materials by laser diffraction/scattering method". Refers to 90% particle size. For the particle size distribution measurement, for example, a laser diffraction/scattering type particle size distribution measuring device can be used.

Next, as shown in FIG. 1, the crushed waste is subjected to a first sieving process. As a result, it is possible not only to selectively remove coarse metal wires that tend to get entangled in the sieve, but also to separate coarse metal pieces and resin as the sieve.
In the first sieving step, the crushed waste is filtered using a comb-tooth-type inclined sifter with a sieve mesh of less than 20 mm.
The comb tooth type inclined sieve may be of vibrating type or fixed type.
The sieve mesh is preferably 8 mm or more and 17 mm or less, more preferably 8 mm or more and 15 mm or less, from the viewpoint of improving the sorting accuracy.
The cross section of the comb teeth may be square, inverted triangle, or round, and the tip shape may be flat, conical, or truncated.
The angle of inclination is preferably 10 to 60°, more preferably 20 to 55°, even more preferably 30 to 50°, in order to facilitate the metal wire to slide down. If the tilt angle exceeds 60°, particles smaller than the sieve mesh repelled by the comb teeth may be recovered as the upper sieve.
In order to increase the sorting accuracy, the comb teeth may be arranged in multiple stages, but in order to prevent the metal wire from remaining on the comb teeth, the upper or lower comb teeth and the shaft that supports them should not come into contact with each other. should be placed in
Note that a commercially available device may be used as the comb tooth type inclined sifter, and examples thereof include a grizzly feeder and a finger screen.

Next, as shown in FIG. 1, the under-sieves obtained in the first sieving step are subjected to the second sieving step, and sieved into two or more grain groups.
A punching metal or comb type sieving machine is used for the second sieving. By using a perforated metal or a comb-tooth sieving machine, it is possible to prevent fine metal wires from entangling and sticking to the sieve mesh. In addition, if a sieve with a small wire diameter such as a woven mesh (plain weave, twill weave, etc.) is used, the shape of the metal wire after the crushing process will be curved, U-shaped, spiral, or lumpy, so it will be caught by the wire mesh. , or entangled, making sieving difficult.
As the punching metal, for example, a steel plate having a plurality of holes formed therein can be used. The shape of the hole may be, for example, square hole (square, rectangle, etc.) or round hole (circle, oval, etc.).
The comb-tooth sieving machine may be, for example, a fixed screen type, a horizontal movement type (in-plane movement type), a vertical movement type, a vertical in-plane rotation type, a three-dimensional vibrating sieve type, or the like.
The sieve mesh is preferably 10 mm or less. If the number of stages is small, the efficiency in the physical sorting process described later is lowered, so two or more stages are preferable.
When two or more stages are provided, two or more sieves may be provided in one machine, or two or more sieves having one sieve may be provided in series. In this case, the mesh size of the first stage is preferably 4 to 10 mm, and the mesh size of the second and subsequent stages is preferably 1/2 or less of the mesh size of the previous stage.
Examples of the hole arrangement include, but are not limited to, 60° staggered, 45° staggered, and side-by-side.
Also, the pitch of the holes is preferably such that the pitch/hole diameter ratio is 1.5 to 2.5. If it is less than 1.5, the pitch is short and the metal wire tends to be entangled between the holes.

Next, as shown in FIG. 1, each particle group obtained in the second sieving step is subjected to physical separation to separate into metals and non-metals.
Metals include metal wires (mostly copper) as well as plate-shaped or granular metals. Most of the plate-shaped or granular metals are, for example, stainless steel, aluminum, brass, copper, gold, Some contain precious metals such as silver, platinum and palladium.
Non-metals include resins, rubbers, etc., and can be reused as solid fuels, for example.

As physical sorting, one or more selected from specific gravity sorting, eddy current sorting, shape sorting, color sorting, and electromagnetic induction sorting may be performed.
Gravity sorting can be carried out using a known gravity sorter, which may be dry or wet. A dry table-type gravity sorter is preferred, and an air table is more preferred.
In specific gravity sorting, for example, when an air table is used, the waste plastic fragile material supplied to the upper surface of the vibrating table is floated from the upper surface of the vibrating table by the air flow passing through the vibrating table. Heavy objects with high specific gravity move to the lower layer and light objects with low specific gravity move to the upper layer due to the vibration applied in the tilting direction of the table, and the heavy objects on the lower layer receive frictional force and vibration force from the upper surface of the vibrating table. , and the lightweight object on the upper layer is pushed obliquely downward from the upper surface of the vibrating table without being subjected to frictional force and vibrational force. Then, heavy objects and light objects are discharged separately from the vibrating table, metals are recovered as heavy products, and non-metals such as resins are recovered as light objects. The metal wire is pulverized into fine particles with almost no entanglement, and since the particle size is adjusted by pulverization and sieving in advance, it can be efficiently recovered as metal.

A known eddy current sorter can be used for eddy current sorting, and although not particularly limited, examples thereof include a rotating magnet type, a straight belt conveyor type, and a rotating cylindrical type.
In eddy current sorting, for example, due to the interaction between the moving magnetic field and the induced current generated inside by receiving the electromagnetic induction action of the moving magnetic field of the rotating magnet provided on the leading end side of the conveyor belt, the leading end side of the conveyor belt Thrust is applied to the transported waste in the direction of rotation of the rotating magnet body, and it can be used to separate plate-like and granular metal pieces that are easy to jump, metal wires that are difficult to jump (mainly copper wires), and non-metals such as resin and glass that do not jump. can be selected. Since metal wires are thin, they are less likely to jump than plate-like or granular metal pieces. Further, if the collected material is subjected to eddy current screening again and a branch plate is installed at a position where only plate-like and granular metal pieces are collected, only the metal wires can be collected.
The rotation speed of the rotating magnet is preferably 1500 rpm or more, more preferably 3000 rpm or more, and even more preferably 4500 rpm or more.

In the shape sorting, if only the plate-like and granular materials are removed by air, only the metal wire mainly composed of copper can be left.
Color sorting can leave only metals such as copper and brass by removing only silver, black, and gray with air.
Electromagnetic induction sorting is excellent in that it collects coarse-grained metals of several millimeters or more by blowing them off with air.
In addition, resin and glass may be mixed in the recovered metal. The quality of metal can be improved.

(Second embodiment)
FIG. 2 shows a flow chart of the waste disposal method according to this embodiment.
In the processing method according to the present embodiment, as shown in FIG. 2, a heating step of heating the waste containing the metal wire is first performed in the same manner as in the first embodiment. Note that the specific configuration of the heating process is as described in the first embodiment.

Next, as shown in FIG. 2, the waste after heating is subjected to a binding step for binding metal wires in the waste. By intentionally causing the metal wires contained in the waste to entangle with each other, troubles caused by the metal wires can be further suppressed in subsequent treatment steps.
In the tying process, the high-temperature waste discharged from the heating furnace is cooled, and in the process of conveying the waste to the next process, the waste may be scraped up to cause entanglement of the metal wires. For example, for cooling, it is possible to use an indirect rotary cooler having a shell with scraping blades, or a cooling screw conveyor that rotates a shaft with blades while cooling with water. Further, during transportation, a screw conveyor capable of rotating a shaft with blades, or a screw conveyor capable of rotating a shaftless spiral can be used. By scraping up the heated waste during cooling and/or transportation in this way, the resin-based particles and metal pieces are pushed into the lower part of the packed bed, while the metal wires are scraped to the surface of the packed bed. Since it is raised, the metal wires in the vicinity are entangled with each other and gradually become coarse.

Next, as shown in FIG. 2, a crushing step is performed to crush the bound waste, and the crushed waste is subjected to a first sieving step. The specific configurations of the crushing step and the first sieving step are as described in the first embodiment.

Next, as shown in FIG. 2, the under-sieved material obtained in the first sieving step is subjected to wind screening to separate heavy materials and light materials. As a result, metals, glass, undecomposed resins, and large-sized particles contained under the sieve can be recovered as heavy materials, and cotton-like foreign matter, fine powder, and fine particles can be removed as light materials.
A known wind sorting machine can be used for the wind sorting step, and although not particularly limited, examples thereof include a zigzag type and an internal circulation type.
In wind sorting, for example, when an internal circulation system is used, if a fan creates an air flow from bottom to top, heavy items contained under the sieve move downward against the air flow, while light weight items move downward. Objects move upwards with air currents. In this way, heavy objects and light objects are sorted, and the heavy objects are supplied to the next process.
When sorting by wind, it is preferable to set the wind speed for sorting by wind so that metal, glass, undecomposed resin, and particles with a large particle size are mainly on the heavy side. Specifically, the wind speed is preferably 5 m/s or higher, more preferably 7 m/s or higher, and even more preferably 8 m/s or higher. The upper limit of the wind force can be set appropriately depending on the type of waste, and is usually 30 m/s or less. , preferably 15 m/s or less. The collected lightweight materials can be used as an alternative fuel to pulverized coal in cement kilns and the like. In addition, the average particle size (D50) of lightweight materials is about 0.5 to 3 mm, which is sufficiently small. The average particle size (D50) refers to the cumulative 50% particle size in the volume-based particle size distribution described above.

Next, as shown in FIG. 2, the heavy objects separated by wind separation are magnetically separated into magnetized and non-magnetized objects. As a result, the metal can be efficiently recovered as the magnetic substance, and the contamination of the magnetic substance with fibers or the like can be prevented. Moreover, by removing the magnetic substance, it is possible not only to reduce the amount of non-magnetic substance to be processed in the next step, but also to recover the metal wire mainly composed of the copper wire.
For magnetic separation, a known magnetic separation machine can be used, and for example, any of a drum type, a pulley type, and a suspension type can be used, and there is no particular limitation.
In magnetic separation, for example, a magnet drum in which a high magnetic field exists, a belt conveyor (moving belt) wound around the magnet drum, and a feeder that supplies samples onto the belt surface of the belt conveyor. A device is used to separate magnetic and non-magnetic materials. The surface magnetic flux density of the magnetic force sorter is preferably 40 to 300 mT, because if the magnetic force is too strong, the melted resin containing the particles and powders of iron and magnets will also be recovered.

Next, as shown in FIG. 2, the non-magnetic substances separated by the magnetic separation are subjected to a second sieve separation process, a physical process. The specific configurations of the crushing step and the first sieving step are as described in the first embodiment.

(Third Embodiment)
FIG. 3 shows a flow chart of the waste disposal method according to this embodiment.
The processing method according to the present embodiment, as shown in FIG. 3, treats the sieved waste obtained in the first sieving process. In addition, any of 1st Embodiment and 2nd Embodiment which were demonstrated above may be sufficient as the sieve top obtained by the 1st sieve selection process.
The sieves obtained in the first sieving step also contain not only resin and metal pieces but also metal wires. Therefore, metals and non-metals are recovered also from this sieve.
Since the metal wire is thin and has a small repulsive force, the metal wire cannot be recovered to the conductive product side only by eddy current sorting. Therefore, in this embodiment, eddy current sorting and specific gravity sorting are combined. Thereby, the resin and the metal wire can be efficiently separated. Gravity sorting can use liquid or solid as a medium, and examples thereof include heavy liquid sorting and fluidized bed sorting. In the specific gravity sorting, metal wires having a specific gravity of 3 or more are preferably recovered as sediments.
A specific configuration of the eddy current sorting is as described in the first embodiment.
As shown in FIGS. 3A and 3B, either the eddy current selection or the specific gravity selection may be performed first. In any order, the resin, the metal pieces and the metal wire can be recovered. The steps shown in (a) and (b) of FIG. 3 are as follows.
(a) after the sieve top obtained in the first sieve sorting step is eddy current sorted to separate the conductive product and the non-conductive product, the non-conductive product is gravity sorted to separate the floating product and the submerged product; (b) After the sieve top obtained in the first sieve sorting step is gravity-sorted to separate floating matter and settled matter, the settled matter is subjected to eddy current separation to separate conductive products and non-conductive products. After separating into conductive products, metal wires are recovered as non-conductive products

Although the present invention has been described in detail based on the preferred embodiments, the present invention is not limited to the above embodiments. Various modifications are possible for the present invention without departing from the gist thereof. For example, in the first embodiment, after the heating step and before the crushing step, the heated waste may be subjected to a binding step for binding metal wires in the waste. By intentionally causing entanglement of the metal wires contained in the waste in the tying step, it is possible to further suppress troubles caused by the metal wires in the subsequent treatment steps.
Moreover, in the second embodiment, the magnetic force sorting step is performed after the wind sorting step, but it is also possible to perform the magnetic force sorting step before the wind sorting step. In this case, the collected magnetic substances may be subjected to wind separation treatment to remove fibers and metals.
Furthermore, the air sorting process and the magnetic sorting process can be performed in any order either after the heating process or before the physical sorting process. For example, the following methods can be mentioned.
(c) The waste after the heating process is magnetically sorted to separate it into magnetic and non-magnetic substances, and the non-magnetic substances are sorted by air force to separate heavy and light weights. Method of subjecting to the sieving step (d) The under-sieving after the first sieving step is separated into heavy objects and light objects by wind force separation, and the heavy objects are separated into magnetic substances and non-magnetic substances by magnetic force separation. After that, a method of subjecting the non-magnetic substance to a second sieve selection step

EXAMPLES The embodiments of the present invention will now be described more specifically with reference to Examples. However, the present invention is not limited to the following examples.

The apparatus used in this example is as follows.
(1) Heating furnace An externally heated rotary kiln was used.
(2) Cooling/conveying machine An indirect rotary cooler and a water-cooled shafted screw conveyor (both manufactured by Hokko Kakoki Co., Ltd.) were connected in this order and used.
(3) Crusher A hammer crusher (MHM-50R, manufactured by Miike Iron Works) was used with a screen of φ20 mm attached.

(4) Sieving machine used in the first sieving process A comb tooth type inclined sieving machine was used. The specifications are as follows.
A round bar with an outer diameter of φ8 mm, a screen mesh (=interval between each round bar) of 8 to 20 mm, an inclination angle of 40°, and a fixed type (5) Wind sorter A zigzag wind sorter (manufactured by Miike Iron Works) was used.
(6) Magnetic Sorter A drum type magnetic sorter (RENS-φ318×350L, manufactured by Nippon Magnetics) was used.

(7) Sieving machine used in the second sieving process/first-stage sieving Any one of the following was used. Specifications are also shown.
(a) Comb-tooth sieving machine Round bars with an outer diameter of φ8 mm, screen mesh (=interval between each round bar) of 10 mm, tilt angle of 40°, fixed type (not vibrating type)
(b) Cylindrical vibration sieving machine (KF-1000-3D, manufactured by Kowa Kogyosho)
Punching metal (round holes 60° zigzag), hole diameter 4 mm (pitch 6 mm) or 10 mm (pitch 15 mm)
(c) Cylindrical vibrating sieving machine (KF-1000-3D, manufactured by Kowa Kogyosho)
Woven net (twill weave), 10 mm

- Second-stage sieve selection Either of the following was used. Specifications are also shown.
(d) Cylindrical vibrating sieving machine (KF-1000-3D, manufactured by Kowa Kogyosho)
Punching metal (round holes 60° zigzag), hole diameter 2 mm (pitch 3 mm) or 4 mm (pitch 6 mm)
(e) Cylindrical vibrating sieving machine (KF-1000-3D, manufactured by Kowa Kogyosho)
Woven net (twill weave), 4 mm

Examples 1-4 and Comparative Examples 1-4
Shredder dust containing electrical appliances for home and business use, furniture, etc. was used as the waste containing metal wires, and was treated according to the flow chart shown in FIG. Specifically, it is as follows.
(Heating process)
The waste was embrittled by feeding it into a heating furnace at 350° C. at a rate of 1000 kg/h.
(Binding process)
The waste after the heating process carried out from the heating furnace was cooled while being conveyed in this order through an indirect rotary cooler and a water-cooled shafted screw conveyor. In addition, during the transportation, the waste was lifted up to promote the entanglement of the metal wires.
(Crushing process)
The waste after the wrapping process was crushed with a hammer crusher. The hammer crusher was equipped with a screen with an opening diameter of 20 mm, and the under-sieve was collected.
(First sieve sorting step)
The under-sieves obtained in the crushing step were screened using the sieves shown in Table 1 to separate the over-sieves and under-sieves.
(Wind sorting process)
The under-sieved material obtained in the first sieving process was subjected to wind screening at a wind speed of 9.0 m/s to separate heavy materials and light materials.
(Magnetic selection process)
The heavy objects obtained in the air sorting process were magnetically sorted with a magnetic force of 3000 gauss to separate them into magnetized and non-magnetized materials.
(Second sieve sorting step)
The non-magnetic substances obtained in the magnetic separation step were screened using the sieves shown in Table 1, and separated into an upper sieve and a lower sieve (first stage).
The under-sifter was further sieved using the sieves shown in Table 1 to separate the over-sifter and the under-sifter (second stage).
(physical sorting)
The three grain groups obtained in the second sieving step were separated into metal and non-metal using an air table.

Table 1 shows the types of sieving machines used in the first and second sieving steps of each example and comparative example. Table 2 shows the balance of the recovered material in each step. In Tables 1 and 2, "-" means that the process was not performed, and in Table 2, if a sorting failure occurred during the process, Process balance results are not shown.

From Table 2, waste containing metal wires is heated to embrittlement, the embrittled waste is crushed, and the crushed waste is sieved using a comb tooth type inclined sieve with a mesh size of less than 20 mm. However, by further sieving with a specific sieve and then physically sorting, it is possible to suppress troubles caused by metal wires, so it is possible to efficiently and stably treat waste containing metal wires.

Claims (5)

A heating step of heating the waste containing the metal wire;
A crushing step of crushing the waste after heating;
A first sieving step of separating the crushed waste into upper and lower sieves using a comb-teeth type inclined sieve with a screen mesh of less than 20 mm;
A second sieving step of sieving the under-sieves obtained in the first sieving into two grain groups or three or more grain groups with a punching metal or a comb-tooth sieve;
Each particle group obtained in the second sieve sorting is subjected to one or more physical sorting selected from specific gravity sorting, eddy current sorting, shape sorting, color sorting and electromagnetic induction sorting, and physical separation into metal and non-metal A method of treating waste, including a sorting process. 2. The method of treating waste according to claim 1, further comprising a binding step for binding together the metal wires in the heated waste after the heating step and before the crushing step. 3. The method of treating waste according to claim 1, wherein in the heating step, the waste containing the metal wire is heated to 250-500.degree. 4. The method for treating waste according to any one of claims 1 to 3, wherein the comb tooth type inclined sieve used in the first sieving step has a sieve mesh size of 8 mm or more and 15 mm or less. 5. The method for treating waste according to any one of claims 1 to 4, wherein the mesh size of the punching metal or comb-type sieve used in the second sieving step is 10 mm or less.

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