JP5259231B2 - Method for recovering valuable metals from waste wires - Google Patents

Description

The present invention relates to a method for recovering valuable metals from waste electric wires including oil-carrying wires (also referred to as ASR oil-carrying harnesses) generated in large quantities from discarded automobiles.

Waste electric wires recovered from discarded automobiles contain not only copper, but also metals such as aluminum and iron, for example, and thus have utility value as resources.
Thus, for example, Patent Document 1 discloses a method in which a waste electric wire is chopped by nugget treatment, separated into a conductor component and a resin component, and these are separated by specific gravity.
In addition, as described in Patent Document 2, the waste wire is crushed and subjected to specific gravity selection twice, or as described in Patent Document 3, the waste wire is divided and cut into a plurality of parts, A method has been proposed in which a flaw is applied and pressure is separated by a pressure roll.

JP 2002-75094 A JP 2001-184959 A JP 2001-351450 A

However, the conventional method still has the following problems to be solved.
Since waste electric wires collected from discarded automobiles have oil attached to their surfaces and are easily elongated and entangled, the physical separation accuracy such as specific gravity selection cannot increase the metal separation accuracy. For this reason, there is a problem that the quality of the recovered metal is lowered, the use of the metal is limited, and the volume is increased by the amount of impurities mixed in the metal, resulting in an extra transportation cost. It was.
Furthermore, for example, waste electric wires generated from waste home appliances, communication devices, computers, and the like have a copper tape wrapped around a vinyl tape (for example, a degaussing coil), and are difficult to shear. When the tape is peeled off, the adhesive remains on the surface and becomes sticky, which makes it difficult to perform subsequent processing operations.

The present invention has been made in view of such circumstances, and an object of the present invention is to provide a method for recovering valuable metals from waste electric wires that can efficiently treat waste electric wires and make them more valuable valuables.

Valuable metal recovery process from the waste wire according to the present invention along the object, a waste wire comprising oil electric wire with a is roughly cut into 3cm or less in advance biaxial shearing machine material, placed in a rotary kiln, 350 ° C. Heating using superheated steam at 550 ° C. or lower, carbonizing a portion other than the contained metal , and cooling to 100 ° C. or lower by cooling in an oxygen-free state with a cooling means attached to the rotary kiln ;
The waste electric wire treated in the first step is crushed using a rotary impact crusher or a ball mill, and a granular material (including linear materials) made of powder mainly composed of carbide and other metals. A second step,
And a third step of separating the granular material and powder generated in the second step by a sieve sorter having an opening of 0.1 to 0.8 mm.
In the method for recovering valuable metals from waste wires according to the present invention, the waste wires preferably include a degaussing coil.

In valuable metal recovery process from the waste wire according to the present invention, the processing time by the superheated steam is preferably not less than 30 minutes 15 minutes.

Since the valuable metal recovery method from waste wires according to claims 1 to 3 heats the waste wires using superheated steam, after treating with superheated steam, the oil attached to the surface of the waste wires is degreased, Since only the metal and carbide are used, the quality of the metal can be improved by subsequent physical treatment. Moreover, since the oxidation of the metal contained in the waste electric wire can be prevented, the metal recovery efficiency is increased. Further, the amount of gas generated is smaller than that in the case of combustion treatment, and the generated gas has a small amount of dioxin and contains oil, so that it can be recovered as fuel or other resources.
Furthermore, since it is a continuous process using a rotary kiln, the heat treatment of the waste wire can be performed continuously, and the processing time can be shortened and the processing amount can be increased.

Valuable metal recovery process from the waste wire of claim 1 is in the discharge side of the rotary kiln, since the cooling means is provided for discharging cooling the treated product of the first step in an oxygen-free state, metal Since it is not oxidized and the amount of flight due to a flame or the like is reduced, the metal recovery rate is improved and the problem of environmental pollution due to the discharged metal is also reduced.

Since the waste electric wire is roughly cut to 3 cm or less by a biaxial shearing machine, it is easy to carry, process in the rotary kiln, and handle thereafter.
And since the crushing of the second step is performed by a rotary impact crusher and a ball mill, the carbide can be separated by impact, and the powder mainly composed of carbide and the granular material composed of other metals. Processing efficiency can be increased.

Next, embodiments of the present invention will be described with reference to the accompanying drawings for understanding of the present invention.
Here, FIG. 1 is a flow chart of a method for recovering valuable metals from waste wires according to the first embodiment of the present invention, and FIG. 2 is a recovery of valuable metals from waste wires according to the second embodiment of the present invention. FIG. 4 is a flow diagram of a method.

As shown in FIG. 1, in the method for recovering valuable metals from waste electric wires according to the first embodiment of the present invention, the waste wires are put into a rotary kiln and heated using superheated steam (hereinafter also referred to as superheated steam). (Pyrolysis), the first step of carbonizing the portion other than the contained metal, the waste electric wire treated in the first step is crushed, and the particles are composed of powder mainly composed of carbide and other metals A second step of making a product, and a third step of separating the granular material and powder produced in the second step. This will be described in detail below.

First, collect the waste wires from various places.
This waste electric wire includes an oil-equipped electric wire (also referred to as an ASR oil-equipped harness) generated from a discarded automobile. In this oil-coated electric wire, the periphery of the copper wire is covered with various plastics and rubber, and the oil adheres to the surface. In addition, a board | substrate (copper and aluminum) and a metal component (iron) are partially attached to the electric wire with oil.
Here, the total amount of the waste electric wire may be an oil-attached electric wire. However, for example, the waste electric wire may be a waste electric wire generated from, for example, a waste home appliance, a communication device, or a computer, specifically, a copper wire. A degaussing coil in which a vinyl tape is wound around (a sticky substance is attached) may be included.

This waste electric wire is roughly cut to about 10 cm (more preferably 5 cm, still more preferably 3 cm) or less with a biaxial shearing machine. In addition, since it is only necessary to roughly cut the waste electric wire, the lower limit value is not specified, but it is, for example, 1 cm or more, further 2 cm or more.
As this biaxial shearing machine, for example, as described in JP-A-7-155630, JP-A-2002-355575, JP-A-2005-270838, etc., two pieces provided with crushing members are provided. There are some which are arranged with the shafts facing each other and put the waste electric wire in the middle position and crush it.
Thereby, the process by the rotary kiln sent after that can be made smooth, for example, conveyance with a screw conveyor etc. can be made smooth.

The coarsely cut waste electric wire is subjected to a magnetic separation process using a magnetic separator to remove magnetic deposits (mainly iron). In this case, it is preferable that the magnetic field of the magnetic separator is appropriately reduced so that the iron adhered with the resin is not removed.
Thereby, only iron simple substance can be sorted beforehand.
In addition, since this process is arbitrary, it does not need to perform depending on the kind (amount of the metal which comprises a waste wire) of a waste wire.

Next, the roughly cut waste electric wire is placed in a rotary kiln and heated using superheated steam as a heat source. As a rotary kiln, the thing of patent 3602504 is used, for example. The rotary kiln includes a first rotary kiln that performs drying of the processing raw material, and a second rotary kiln that performs dry distillation processing of the processing raw material dried by the first rotary kiln with higher-temperature superheated steam. Depending on the state of the waste electric wire, the first rotary kiln may be used for drying treatment, or the first rotary kiln may not be used. This heating is preferably performed in an oxygen-free or diluted oxygen state (for example, 5% by volume or less, preferably 3% by volume or less, and further 1% by volume or less) in the rotary kiln.
Thereby, the volume reduction process of a waste electric wire can be performed in large quantities and continuously. In addition, since the weight of a waste wire reduces about 15-40 mass% by performing carbonization processing of a waste wire, the subsequent process can respond also to a batch type.

In addition, it is preferable that the temperature of superheated steam shall be 350 degreeC or more and 550 degrees C or less.
Here, when the temperature of the superheated steam is less than 350 ° C., the temperature is too low, and thermal decomposition of oil adhering to the waste wire, plastics and rubber in the waste wire does not proceed, and carbonization is difficult. On the other hand, when the temperature of the superheated steam exceeds 550 ° C., the temperature is too high, causing a problem that the copper becomes brittle.
Therefore, although the temperature of the superheated steam is set to 350 ° C. or more and 550 ° C. or less, it is preferable that the lower limit is 400 ° C. and the upper limit is 500 ° C.

Moreover, it is preferable that the processing time by superheated steam shall be 15 minutes or more and 30 minutes or less (here 20-30 minutes).
Here, when the treatment time with superheated steam is less than 15 minutes, the treatment time is too short, and the thermal decomposition of the oil adhering to the waste wire, the plastics and rubber in the waste wire does not proceed, and the carbonization treatment is difficult. is there. On the other hand, when the treatment time with superheated steam exceeds 30 minutes, the treatment time is too long and the loss of heat energy increases.
Therefore, although the treatment time with superheated steam is 15 minutes or more and 30 minutes or less, the upper limit is preferably 20 minutes.

The discharge mechanism of this rotary kiln (second rotary kiln in the same patent) has a discharge screw conveyor (an example of a cooling means), and the processed raw material is flowed from the inlet side of this discharge screw conveyor. In addition, the superheated steam or saturated steam filled in the rotary kiln is caused to flow through the screw conveyor to be in an oxygen-free state. And when it is humidified and comes out of the exit of the screw conveyor for discharge | emission in the process which is flowing through the inside of a screw conveyor, it is cooled to 100 degrees C or less.

Thereby, after the treated carbide is discharged, it is not reburned and the heated metal is not oxidized. Further, since there is no metal oxidation even in the rotary kiln, it hardly flies as an oxide.
Therefore, most of the metal contained in the waste electric wire can be recovered (improvement of metal recovery rate).
In addition, when the roughly cut waste wire that is a raw material in the rotary kiln is pyrolyzed, for example, 15 to 40% by weight becomes volatiles with respect to the whole (waste wire 100% by weight), and the remaining 60 to 85% by weight. Is recovered.

In the above rotary kiln carbonization treatment, a large amount of exhaust gas is generated, but since it is processed with high-temperature steam, the generation of dioxins is reduced. Since it occupies most, a gas with a high calorific value can be obtained, and it further has a part which becomes liquefied and becomes oil.
Therefore, the exhaust gas can be used effectively as fuel (the first step).

A processed product (carbonized waste electric wire) discharged from a rotary kiln (specifically, a discharge screw conveyor) is crushed by an impact crusher, a ball mill, or a rod mill. As this impact crusher, for example, a rotary impact crusher described in Japanese Patent No. 2909503 can be used.
By this crushing treatment, the carbide adhering to the periphery of the metal is crushed and removed almost completely, and the powder mainly composed of carbide (carbide is, for example, 80% by mass or more, further 90% by mass or more, other Examples of the component include ceramics, which may be 0% by mass) and other granular materials (for example, the metal content is 80% by mass or more). At this time, in addition to the crushing effect, the effect of rounding the shape of the metal can be added, so that the metal (copper wire or the like) does not pierce the mesh at the time of subsequent sieving, and the sieving efficiency can be increased ( The second step).

Since it is divided into +0.5 mm (0.5 mm over) and -0.5 mm (0.5 mm under) by the above crushing, it is classified by a sieve sorter.
Here, +0.5 mm portion refers to a sieved product when sieved with a sieve having an opening degree (opening) of 0.5 mm, and −0.5 mm component refers to a sieved product. The +0.5 mm portion is a granular material containing a metal as a main component (for example, including a linear material or a lump shape), and the −0.5 mm portion is a powder mainly composed of carbide.
By this sieving treatment, it can be separated into granular materials and powders (the third step).

After this, the granular material is applied to a magnetic separator (magnetic separator) to remove the magnetized metal, and then further applied to an eddy current separator (non-ferrous metal separator) to produce a highly conductive metal such as copper or aluminum and other metals. Can be selected.
The generated powder (mainly carbide) is shipped after granulation and molding in consideration of subsequent handling.
By the above method, a waste electric wire can be processed efficiently and it can be made a valuable material with higher value.

Next, a method for recovering valuable metals from waste wires according to the second embodiment of the present invention will be described. This method is based on the valuable metals from waste wires according to the first embodiment of the present invention described above. In the recovery method, since the heating condition of the roughly cut waste wire with superheated steam is changed, only different parts will be described below.
The waste electric wire roughly cut by the same method as the valuable metal recovery method from the waste electric wire according to the first embodiment of the present invention described above is put into a rotary kiln and heated with superheated steam.

The temperature of the superheated steam is preferably more than 550 ° C. and 800 ° C. or less.
Here, when the temperature of the superheated steam exceeds 550 ° C., the carbonization of the plastics and the rubber in the waste electric wire can be performed, but as described above, there is a problem that the temperature becomes too high and the copper becomes brittle. For this reason, when an impact is applied to this copper, it is finely pulverized and the sieving accuracy is lowered. On the other hand, when the temperature of the superheated steam exceeds 800 ° C., the temperature is too high, causing a problem of heat resistance of the device.
Therefore, when the temperature of the superheated steam that heats the waste wire exceeds 550 ° C. and is 800 ° C. or less (preferably, the upper limit is 750 ° C., and further 700 ° C.), the treatment is performed by the following method.

The processed product (carbonized) is cooled and discharged from a rotary kiln (specifically, a screw conveyor for discharge) in the same manner as the method for recovering valuable metals from waste electric wires according to the first embodiment of the present invention described above. The waste electric wire) is separated into a non-magnetized material and a magnetic material (iron) by applying a magnetic separator (magnetic separator) (the first step).
Next, the separated non-magnetic product is crushed. In addition, since copper in the non-magnetized material becomes brittle and may be scattered when crushed, it is preferable that the crushing is performed by a wet process (for example, a wet ball mill). By this crushing treatment, the carbide adhering to the periphery of the metal is crushed and almost completely removed, and a particulate material mainly composed of carbide and other metals (for example, the metal content is 80 mass). % Or more) (the second step).

By the above crushing, it is divided into a granular material containing a metal as a main component (for example, including linear or lump) and a powder mainly composed of carbide. The product and powder are separated (the third step).
Since the obtained granular material is almost copper, for example, it can be reused after being subjected to a drying treatment, but if necessary, it is applied to the above-described magnetic separator, and further to an eddy current separator, such as copper and aluminum. You may sort into a metal with good electroconductivity, and another metal.
By the above method, a waste electric wire can be processed efficiently and it can be made a valuable material with higher value.

Next, examples performed to confirm the operation and effect of the present invention will be described.
Here, a description will be given of the result of heat treatment with superheated steam using oil-filled electric wires (hereinafter referred to as waste electric wires) generated from discarded automobiles as processing raw materials in the rotary kiln. In addition, the processed waste electric wire contains about 39 to 52% by mass of copper, and on average, copper: 47.0% by mass, iron: 12.9% by mass, aluminum: 0.4% by mass, This includes plastic: 37.6% by mass, and other: 2.1% by mass.
In the heat treatment of the treatment raw material, the temperature of the superheated steam was changed within a temperature range of 300 to 600 ° C., and the treatment time was changed within a range of 15 minutes to 30 minutes. The results are shown in Table 1.

As is apparent from Table 1, test no. About any of 1-8, it has confirmed that about 15-42 mass% of the whole quantity of a processing raw material can be volume-reduced by heat-processing a processing raw material with superheated steam. It was also confirmed that the amount of plastic can be reduced by about 64 to 94% by mass of the total amount of plastic.
As described above, it was found that the treatment raw material was treated with superheated steam, so that the volume could be significantly reduced. However, it was easy to peel off carbides from the metal (improvement of the quality of the recovered metal) and the brittleness of the metal. In view of the suppression of the conversion, the treatment is preferably performed at 350 to 550 ° C., more preferably 400 to 500 ° C.

Here, the thermal decomposition behavior of the processing raw material by superheated steam and the thermal decomposition behavior of the plastic are shown in FIGS. 3 (A) and 3 (B), respectively.
As apparent from FIGS. 3 (A) and 3 (B), there was a tendency that the weight loss rate of the processing raw material and the plastic increased as the processing temperature increased. On the other hand, with respect to the treatment time, it was confirmed that even if the treatment time was shortened, as shown in FIG. In addition, although the reduction rate of the processing raw material shown in FIG. 3 (A) is about 10% by mass due to the length of the processing time, this is attached to components other than plastic, for example, the processing raw material. This is probably due to the amount of oil.
Accordingly, the treatment time does not need to be particularly limited, but it is preferably 15 to 30 minutes, more preferably about 15 to 20 minutes in consideration of economical and reliable carbonization treatment.
From the above, it has been confirmed that by applying the present invention, waste electric wires can be efficiently processed and further made valuable valuables.

As described above, the present invention has been described with reference to the embodiment. However, the present invention is not limited to the configuration described in the above embodiment, and the matters described in the scope of claims. Other embodiments and modifications conceivable within the scope are also included. For example, the case where the valuable metal recovery method from the waste electric wire of the present invention is configured by combining some or all of the above-described embodiments and modifications is also included in the scope of the right of the present invention.
Moreover, in the said embodiment, although the sieve which has an opening degree of 0.5 mm is used for the classification of a 3rd process, it has an opening part (classification point) of about 0.1-0.8 mm. Is preferably used.

It is a flowchart of the valuable metal collection | recovery method from the waste electric wire which concerns on the 1st Embodiment of this invention. It is a flowchart of the valuable metal collection | recovery method from the waste electric wire which concerns on the 2nd Embodiment of this invention. (A) is explanatory drawing which shows the thermal decomposition behavior of the processing raw material by superheated steam, (B) is explanatory drawing which shows the thermal decomposition behavior of a plastic.

Claims (3)

A waste electric wire containing an oil-carrying wire that is a raw material roughly cut to 3 cm or less in advance by a biaxial shearing machine is placed in a rotary kiln and heated using superheated steam of 350 ° C. or higher and 550 ° C. or lower, and other than contained metals A first step of carbonizing the part and cooling to 100 ° C. or less by cooling in an oxygen-free state with a cooling means attached to the rotary kiln ;
A second step of crushing the waste electric wire treated in the first step using a rotary impact crusher or a ball mill to form a powder mainly composed of carbide and a granular material composed of other metals; ,
It has the 3rd process which isolate | separates the granular material produced | generated at the said 2nd process, and powder with the sieve sorter which has an opening part of 0.1-0.8 mm, The valuable metal collection | recovery from a waste wire characterized by the above-mentioned Method. The method for recovering valuable metals from waste wires according to claim 1, wherein the waste wires include a demagnetizing coil. The method for recovering valuable metals from waste wires according to claim 1 or 2, wherein the treatment time by superheated steam in the first step is 15 minutes or more and 30 minutes or less. .

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