JPH0931552A - Recycling method for metallic container-mixed waste and device therefor - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a recycling method for metallic container-mixed waste and a device therefor. SOLUTION: This method includes a stage for heat treating the metallic container-mixed waste contg. steel containers and aluminum containers at 300 to 500'C under a controlled oxygen concn., removing org. matter therefrom and peeling the aluminum caps adhered to the steel containers, a stage for magnetically separating the oxide and carbide on the surfaces of the heat treated container waste, a stage for cutting both magnetically separated components to specified sizes, a stage for peeling and removing the oxide and carbide sticking to the surfaces of both components cut to the specified sizes and a stage for separately compressing both components of the specified sizes from which the surface deposits are peeled away to a lumpy form.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a metal waste,
Especially from metal containers such as steel cans and aluminum cans,
The present invention relates to a waste treatment method for separately separating and recovering steel components and aluminum components and reusing them, and an apparatus for carrying out the treatment method. In particular, the present invention is a high-purity, high-density compressed mass that can be directly used as a raw material for iron and aluminum from mixed waste of metal containers such as steel containers and aluminum containers that are discarded without being sorted. The present invention relates to a method and device capable of recovering iron and aluminum. Further, according to the present invention, not only a metal container but also a waste container disposed of together with a glass container, a ceramics container, a plastic container, and the like can be used as a resource without using any manpower as a resource. The present invention relates to a method and an apparatus that can be collected in a state.

[0002]

2. Description of the Related Art Wastes containing various steel containers, aluminum containers, glass bottles, ceramics and plastic containers together depend on human labor to select metal containers such as steel cans and aluminum cans. In the present situation, however, steel and aluminum containers are separated by means such as magnetic sorting and then treated separately for recycling. However, such a method of relying on manual labor is not preferable because it is costly. Even if it is possible to select a steel container and an aluminum container, for example, a steel can has an aluminum lid adhered to its lid, so that the steel can is separated from the aluminum can. There was a problem that it was not possible to obtain a high-quality iron raw material with high purity unless it was removed by relying on human hands.

[0003]

SUMMARY OF THE INVENTION According to the present invention, a metal container composed of a plurality of materials such as a steel can having an aluminum part can be disassembled into its constituent metal parts without manpower. It is an object of the present invention to provide a method and an apparatus capable of recovering highly pure metal that can be separated and reused at a high recovery rate. Also,
INDUSTRIAL APPLICABILITY The present invention treats a garbage bag, which is discharged as waste from a general household or the like, with metal containers such as steel cans, aluminum cans, glass bottles, ceramics, and plastic containers together, and finally processes the final product. It is also an object of the present invention to provide a method and an apparatus capable of recovering a metal component useful for a high purity with a high recovery rate.

[0004]

The present invention for achieving the above object comprises the following methods and apparatuses. (1) A step of heat-treating a mixed waste of metal containers including a steel container and an aluminum container at 300 to 500 ° C. in an oxygen concentration atmosphere controlled to be weakly oxidizing to remove organic substances, and a heat-treated container The process of magnetically separating the waste into steel and aluminum components, the process of separately cutting both of the magnetically separated components into a certain size, and the oxide adhering to the surfaces of both components cut into a certain size. A method of recycling a mixed waste in a metal container, comprising: a step of peeling and removing carbides; and a step of separately compressing both components of a certain size from which surface deposits have been peeled and removed into a compression lump.

(2) The heat treatment under the controlled oxygen concentration is performed under the oxygen concentration condition controlled by the reducing substance supplied into the rotary kiln at 300 to 300 ° C.
The above is characterized in that it is carried out at a temperature of 400 ° C.
(1) A method for recycling the waste mixed with metal containers as described above.

(3) The heat treatment under the controlled oxygen concentration is 300 to 400 under a low oxygen concentration condition controlled by a reducing gas produced by injecting a lower alcohol into the heat treatment zone. The method for recycling the waste mixed with metal containers according to (1) or (2) above, which is carried out at a temperature of ℃.

(4) A rotary kiln equipped with a reducing gas generating substance injecting device, a screw conveyor for introducing waste mixed with metal containers, an oxygen sensor, a combustion burner, and a combustion gas discharge port connected to a secondary combustion chamber, A heat treatment apparatus having a secondary combustion chamber arranged so as to cover the inlet side of the screw conveyor for mixing the metal container mixed waste of the rotary kiln, an apron conveyor arranged at the outlet side of the heat treatment apparatus, and the apron. A magnetic sorter following the conveyor, a plurality of cutting devices following the magnetic sorter, and an oxide layer adhering to the surface of each cut piece obtained from the plurality of cutting devices,
A metal container including a steel container and an aluminum container having a plurality of peeling devices for peeling and removing the carbide layer and a plurality of compression agglomerating devices for separately compressing and cutting the cut pieces obtained from the plurality of peeling devices. Equipment for recycling mixed waste.

(5) The reducing gas generating substance injector is
The recycling apparatus for mixed metal container waste including the steel container and the aluminum container described in (4) above, which is connected to a screw conveyor for inputting mixed waste metal container.

(6) The recycling device for mixed waste of metal containers including the steel container and the aluminum container includes a non-metal container such as a glass container, ceramics, a plastic container, etc. in addition to the metal container for disposal. The recycling apparatus for mixed metal container waste according to (4) or (5) above, which is connected by a conveyor to a raw material separation device that selects only the metal container from the packaging bag.

The metal containers to be heat-treated in the present invention include all steel and aluminum containers used for packaging various beverage cans, various processed foods, confectionery and the like. Such a container usually has an organic film such as paper or plastic, a coating film, a printing layer, an adhesive layer on the outer surface, and also has a layer such as a lining on the inner surface. Therefore, when recovering metal components from such a metal container, these organic substances are incinerated and removed.

The incineration of organic matter by a rotary kiln is usually carried out in the presence of abundant oxygen for the purpose of complete combustion of the organic matter. Then, the loss due to the conversion of the target metal component to the oxide is unavoidable, and the recovery efficiency of the metal component is by no means high.

According to the above-mentioned present invention, by carrying out the heat treatment with the rotary kiln under the controlled oxygen concentration, not only the organic matter adhering to the metal container can be converted into the easily removable substance but also the metal It is possible to avoid conversion loss of the components to oxides, and it is possible to recover the metal components with high efficiency.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION A method and an apparatus for recycling mixed waste in a metal container according to the present invention will be described with reference to the accompanying drawings. FIG. 1 shows the structure of a heat treatment apparatus for carrying out the method for recycling a mixed waste in a metal container of the present invention. FIG. 2 shows a raw material system to be treated supplied to the heat treatment process of FIG. 1 and an exhaust gas treatment system from the heat treatment process.

As shown in FIG. 1, the apparatus of the present invention basically comprises a heat treatment apparatus 1 comprising a rotary kiln 2 and a secondary combustion chamber 3, an apron conveyor 10 following the heat treatment apparatus 1, and Magnetic sorter 11 following apron conveyor 10 and vibrating conveyors 12, 1 following magnetic sorter 11
3 and cutting machines 14, 1 following the vibration conveyors 12, 13.
5 and peeling devices 18 and 19 for peeling and removing oxides and carbides adhering to the small pieces of the steel component and the aluminum component, which are separately cut by the cutting machines 14 and 15.

An outlet of the rotary kiln 2 is shielded from the outside air by an air curtain 7, and a portion including the inlet of the metal container to be treated from the input screw conveyor 4 is placed in the secondary combustion chamber 3. It is arranged in a stored state. The rotary kiln 2 has a burner 6 and an oxygen sensor 5 for measuring the oxygen concentration in the kiln.
An oxygen control device 8 for controlling the oxygen concentration in the kiln based on the detection data of the sensor, and a reducing substance is supplied to a group of metal containers to be treated in the carry-in screw conveyor 4 by a command from the oxygen control device 8. An injecting device 8a and a pressurizing device 8b are installed so that the oxygen concentration in the kiln can be constantly monitored and controlled.

The secondary combustion chamber 3 is provided with a burner 9 for burning the combustion exhaust gas in the kiln containing unburned vaporized organic matter and reducing gas discharged from the inlet side of the rotary kiln 2 into the secondary combustion chamber. I have it. Since the combustion waste gas in the secondary combustion chamber 3 is used for preheating of the metal container to be treated, which is carried into the kiln 2 by the screw conveyor 4 as necessary, and then discharged to the outside, the exhaust gas system in FIG. The exhaust gas cooler 29, the cyclone dust collector 30, the bag filter dust collector 31, and the blower 32 are sequentially processed and discharged.

A magnetic sorter 11 is disposed on the carry-out side of the rotary kiln 2 for selecting the heat-treated mixed metal container carried out from the rotary kiln 2 via the apron conveyor 10. After the magnetic sorter 11, the carbon components and oxide films adhered to a plurality of types of containers such as steel and aluminum containers sorted by the magnetic sorter are partially peeled and removed. A plurality of vibrating conveyors 12, 13 for arranging are arranged, and cutting machines 14, 15 for cutting each of the treated steel component and aluminum component into small pieces of appropriate size are provided on the unloading side of each vibrating conveyor. Are arranged.

The vibrating conveyor 1 is installed in the cutting machines 14 and 15.
6 and 17, stripping devices 18 and 19 for completely stripping and removing oxides and carbides attached to the surfaces of the cut small pieces of steel and aluminum components are connected, The peeling device includes vibration conveyors 20 and 2.
1 and Trommel 23, 24 are connected to compression molding machines 25, 26 for separately compression-molding high-purity steel pieces and aluminum pieces obtained from a peeling device into a lump having an appropriate size and density. .

As shown in FIG. 2, in the screw conveyor 4 for carrying in the metal cans to be processed in the rotary kiln 2, the metal containers to be processed carried in from the conveyor 4 to the rotary kiln 2 are replaced with other glass containers, plastic containers, and ceramics. A series of devices for separating from, such as hopper 3.
3, a series of raw material separating device groups including a carry-in conveyor (not shown), a bag breaking device 35, a conveyor 36, a specific gravity separating device 37, a trommel 38, a conveyor 39, etc. are connected as necessary.

Further, in order to finally remove other components adhering to the respective small pieces from the steel pieces and the aluminum pieces sent from the peeling devices 18 and 19 to the compression molding machines 25 and 26, the compression molding machines are provided. Magnetic sorter 2 in front
2 is preferably installed.

Next, the recycling method of the present invention by the recycling apparatus for mixed waste of metal containers of the present invention will be described with reference to FIGS. 1 and 2. First of all, as shown in Fig. 2, the metal is usually stored in a plastic bag and discarded,
Garbage such as glass, porcelain, and plastic that is mixed is thrown into the hopper 33 as it is without being opened, and is sent from the hopper to the bag breaking device 35 by a conveyor, where any means is used. The plastic bag is torn and the dust is taken out.

The dust taken out by the bag breaking device is then sent to the specific gravity sorter 37 by the conveyor 36, and is separated into glass bottles and ceramics having a large specific gravity and empty cans having a small specific gravity by a method such as air sorting. , The empty cans are further sent to the trommel 38, and the accompanying small glass and small pieces of ceramics and plastic containers are removed by sieving.

The metal container group such as an empty can obtained from Trommel is a metal container mixture mainly composed of an aluminum container and a steel container, and often contains a small amount of plastic bag pieces. The metal container mixture obtained from Trommel is then received on the conveyor 39 and the screw conveyor 4 of the heat treatment apparatus 1 shown in FIG.
Sent to

The above-mentioned raw material separating apparatus and the raw material separating step of FIG. 2 which is performed using the apparatus are performed when the metal container is obtained in a state where the metal container is separated from the wastes made of other non-metallic substances. Of course, this is an unnecessary process.

As shown in FIG. 1, the metal container mixed waste passes through the secondary combustion chamber 3 by the screw conveyor 4, is preheated if necessary, and is carried into the rotary kiln 2. The inside of the rotary kiln 2 is heated to a temperature of 300 to 500 ° C. by the burner 6, and the organic matter forming the coating such as the coating on the surface of the mixed metal container and the printing layer is burned and thermally decomposed. Further, the aluminum lid adhered to the steel can is peeled off from the can body by this heat treatment.

The rotary kiln may be a rotary kiln having a spiral groove inside, but a plurality of parallel bars (or rods) are provided on the inner peripheral surface from the inlet to the outlet so that the kiln can rotate. It is preferable to have an internal kiln structure in which the container to be treated is held and lifted between the bar and the inner mold of the kiln, and is freely dropped when reaching the upper part. The aluminum lid, which is attached to a steel can by such a kiln internal structure,
Drop impact will be applied to ensure separation from the steel can.

The rotary kiln 2 is 300 to 500 ° C.
In addition, the oxygen concentration is always maintained in a predetermined range (weakly oxidizing atmosphere). Excessive oxidation of the surface of a metal container such as an aluminum can or a steel can is prevented by the combustion treatment under the controlled conditions. The oxygen concentration in the furnace is controlled by an oxygen sensor 5 such as a zirconia sensor installed in the rotary kiln 2, and when the oxygen concentration in the furnace exceeds the specified range, an oxygen control device is provided. In response to a command from 8, a suitable amount of reducing substance such as methanol is injected into the kiln using a pressurizing device 8b such as a nitrogen cylinder.

The reducing substance injected from the injection device 8a may be another lower alcohol such as ethanol, or may be a reducing gas such as water gas or methane. May be In the kiln, the plastic bag pieces accompanying the mixed metal container also burn.

An air curtain device 7 is installed on the side of the combusted material carrying-out port of the rotary kiln 2 so that the combustion conditions in the kiln can be easily controlled by blocking the air inside the kiln from the outside air. Has been done. By the burning treatment in the rotary kiln under the above temperature conditions, the aluminum lid body and the like attached to the ordinary steel can by adhesion are separated from the steel can body.

The heat-treated exhaust gas produced in the rotary kiln 2 contains a small amount of combustible gas produced by the decomposition of organic substances on the surface of the metal container and carbon monoxide produced by the decomposition of methanol injected for controlling the oxygen concentration. It is a high temperature gas containing. The rotary kiln exhaust gas is discharged to the secondary combustion chamber 3, where it is completely burned with the air and fuel supplied from the burner 15 and then discharged to the outside of the combustion chamber, and is discharged to the exhaust gas cooler 29 and the cyclone dust collector 3
0, the bag filter dust collector 31, the blower 32, and the like, and then discharged into the atmosphere.

The mixed metal container which has undergone the heat treatment in the rotary kiln 2 is then discharged from the kiln to the apron conveyor 10 and sent to the magnetic separator 11 to be magnetically separated into a steel component and an aluminum component. Both the separated components are then separately passed through a vibration conveyor 12 (aluminum component), 13 (steel component) and a cutting device 14,
Then, it is cut into small pieces of appropriate size to facilitate removal of the oxide and carbide coatings adhering to the surface.

The small pieces consisting of the aluminum component and the steel component obtained from the cutting devices 14 and 15 are separately sent to the peeling devices 18 and 19 via the vibrating conveyors 16 and 17.
Here, the oxide film and the carbide film adhering to the surface are forcibly and completely removed. During this peeling removal operation,
The small pieces are transformed into pellets.

The pellet-shaped steel pieces from which deposits of oxides and carbides have been removed are separately conveyed by the vibrating conveyor 21, and the aluminum pieces are separately conveyed by the vibrating conveyor 20, and the oxides and carbides entrained by the trommel 23, 24 are conveyed. The powder is passed through a compression molding machine 25, 26 while sieving off the powder, and the pelletized small pieces are molded into aluminum pellets and steel pellets having appropriate sizes and densities and stored in stockers 27 and 28. The molded pellet mass has a size and density that can be used as it is as a raw material for iron and aluminum,
And it is a high-purity lump.

The small pieces obtained from the cutting devices 14 and 15 are
As described above, the vibration conveyors 16 and 17, the peeling device 1
Although it is finally sent to the compression molding machines 25, 26 after passing through No. 8, 19, etc., it is necessary because the pellet-like small pieces, particularly steel small-piece components, may be accompanied by a small amount of aluminum component. If so, it is desirable to remove the aluminum component through the magnetic sorter 22 prior to sending the steel pieces to the compression molding machine.

[0035]

According to the apparatus and method for recycling mixed waste in a metal container of the present invention described above, if the waste is a mixed metal can that is categorized and discharged from a general household, it is possible to obtain a It is possible to perform the recycling processing as it is without the need for further sorting work for each type. Further, even if some glass bottles and ceramic products are mixed, they are removed by the operation of removing unnecessary components in each step following the heat treatment step, so that no special selection step is required.

Further, the obtained steel component and aluminum component are highly pure pellet compacts having an appropriate size and weight, which can be used as they are as raw materials for iron and aluminum. Since there is little generation of oxides in (1), there is little loss of metal components constituting the container, and there is an effect that it is possible to provide an apparatus and method capable of obtaining iron and aluminum raw materials with a high recovery rate. In addition, the aluminum lid integrated into the steel can also requires no human
Since the steel can can be easily separated from the steel can body only by controlled heat treatment, the steel can has an excellent effect of being able to be recycled as a steel raw material at a low cost.

[Brief description of drawings]

FIG. 1 is a schematic layout diagram showing a configuration of a recycling apparatus for a metal can mixed waste according to the present invention.

FIG. 2 is a schematic diagram illustrating a raw material separation system and an exhaust gas system of the apparatus of the present invention.

[Explanation of symbols]

1: Heat treatment device, 2: Rotary kiln, 3: Secondary combustion chamber, 4: Screw conveyor, 5: Oxygen sensor, 6:
Burner, 7: Air curtain, 8: Oxygen control device, 9: Burner, 10: Apron conveyor, 11: Magnetic sorter, 12, 13: Vibration conveyor, 14, 15: Cutting machine, 16, 17: Vibration conveyor, 18 , 19: Peeling device, 20, 21: Vibration conveyor, 22: Steel magnetic sorter, 23, 24: Trommel, 25, 26: Compression molding machine, 27: Aluminum lump stocker, 28: Steel lump stocker, 29: Exhaust gas cooler, 30: cyclone dust collector, 31: bag filter dust collector, 32:
Blower, 33: hopper, 34, 36, 39: conveyor, 37: gravity sorter, 38: trommel.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Yoshiaki Yokoyama 1-1-13-2106 Akamidai, Konosu City, Saitama Prefecture

Claims (6)

[Claims] 1. A process for removing organic matter by heat-treating mixed waste in a metal container including a steel container and an aluminum container at 300 to 500 ° C. in an atmosphere controlled to have a weak oxidizing property, and a heat-treated container. A step of magnetically separating the waste into a steel component and an aluminum component, a step of separately cutting both magnetically separated components into a fixed size, an oxide adhering to the surface of both components cut into a fixed size, A method of recycling a mixed waste in a metal container, comprising a step of peeling and removing carbides and a step of separately compressing both components of a certain size from which surface deposits have been peeled and removed into a compressed mass. 2. The heat treatment is performed at a temperature of 300 to 400 ° C. under an oxygen concentration condition in which the reducing substance supplied into the rotary kiln is controlled to be weakly oxidizing. The method for recycling the metal container-mixed waste according to claim 1. 3. The heat treatment is carried out under the condition of oxygen concentration that is controlled to be weakly oxidative by a reducing gas generated by injecting a lower alcohol into the heat treatment zone.
It is performed at the temperature of 0-400 degreeC, The recycling method of the metal container mixed waste of Claim 1 or Claim 2 characterized by the above-mentioned. 4. An apparatus for injecting a reducing gas generating substance, a screw conveyor for introducing mixed waste in a metal container, an oxygen sensor,
A burner for combustion, a rotary kiln provided with a combustion gas discharge port connected to the secondary combustion chamber, and a secondary combustion chamber arranged so as to cover the metal container mixed waste input screw conveyor inlet side of the rotary kiln. A heat treatment device having, an apron conveyor arranged on the outlet side of the heat treatment device, a magnetic sorter following the apron conveyer, a plurality of cutting devices following the magnetic sorter, and obtained from the plurality of cutting devices An oxide layer adhering to each cutting piece surface, a plurality of peeling devices for peeling and removing the carbide layer, and a plurality of compression agglomerating devices for separately agglomerating the cutting pieces obtained from the plurality of peeling devices, Equipment for recycling mixed waste of metal containers including steel containers and aluminum containers. 5. The metal container including a steel container and an aluminum container according to claim 4, wherein the reducing gas generating substance injecting device is connected to a screw conveyor for introducing a metal container mixed waste. Equipment for recycling mixed waste. 6. The recycling apparatus for mixed waste of metal containers including the steel container and the aluminum container includes a metal container, a non-metal container such as a glass container and a ceramics container, and the discarded packaging bag. 6. The recycling apparatus for a mixed waste of metal containers according to claim 4 or 5, further comprising a conveyor connected to a raw material separation device for selecting only the metal containers.