JP2004188324A - Shredder dust separation method - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a separation method for separating plastic dust containing no copper particularly from shredder dust of industrial waste. <P>SOLUTION: The shredder dust separation method is carried out by taking out a mixture of nonferrous metal dust containing at least nonferrous metals and plastic dust containing at least plastics from shredder dust of industrial wastes such as wastes of domestic electric appliances and cars used; generating electrostatic force by mixing a magnetic powder with the mixture and stirring the mixture; sticking the magnetic powder to the surface of the plastic dust by the electrostatic force; and separating the plastic dust and the nonferrous metal dust by magnetic separation of the plastic dust sticking the magnetic powder and the nonferrous metal dust. <P>COPYRIGHT: (C)2004,JPO&NCIPI

Description

[0001]
TECHNICAL FIELD OF THE INVENTION
The present invention relates to a sorting method for sorting shredder dust of industrial waste such as waste home appliances (household electric appliances) and waste vehicles according to the composition.
[0002]
[Prior art]
Technology development for recycling shredder dust from waste home appliances and end-of-life vehicles has been underway for many years, but many have used methods that utilize the difference in specific gravity or the difference in the ease of charging due to substances. However, these have the following disadvantages. That is, in the former method using the specific gravity difference, since the shredder dust to be separated is composed of various miscellaneous substances having similar specific gravities, and has a wide particle size distribution, it is difficult to perform precise separation. There were drawbacks. Further, the latter method utilizing the chargeability has a drawback that it is easily affected by humidity, is not suitable for separating spherical plastics or fibrous plastics, and cannot be efficiently separated.
[0003]
[Problems to be solved by the invention]
For this reason, the above-mentioned shredder dust was not properly classified into the intended type, and eventually, many SDs were forced to landfill. Also, a part of the SD was sometimes incinerated. However, the disposal of landfills and incineration as described above inevitably causes various environmental problems such as elution of heavy metals into the soil, drastic reduction of disposal sites, and release of dioxin into the atmosphere. .
[0004]
The present invention has been made in view of such a problem, and it is an object of the present invention to appropriately sort SD and collect the SD as an intended type, thereby enabling effective use of resources.
[0005]
[Means for Solving the Problems]
Shredder dust sorting device of the present invention, from the shredder dust of industrial waste such as waste household appliances and end-of-life vehicles, take out a mixture of non-ferrous metal dust containing at least non-ferrous metal and plastic dust containing at least plastic, The magnetic powder is mixed with the mixture and agitated to generate an electrostatic force, and the electrostatic force causes the magnetic powder to adhere to the surface of the plastic dust. The plastic dust to which the magnetic powder adheres and the non-ferrous metal are magnetically separated. The plastic dust and the non-ferrous metal are separated by sorting by sorting.
[0006]
BEST MODE FOR CARRYING OUT THE INVENTION
FIG. 1 is a flowchart showing an embodiment of the present invention. The embodiment will be described along this flowchart.
[0007]
First, steps S11 to S13 will be considered. These steps are generally performed as pre-processing, and are processing for obtaining so-called shredder dust. That is, the target dust is crushed (S11), and iron is recovered by magnetic separation (S12). Thereafter, the non-ferrous metal is recovered by wind selection (S13).
[0008]
Next, a peeling process is performed (S14), the coating is peeled off from the coated copper wire, and separated into the copper wire and the coating. For example, a volume reducer is used. That is, the dust that has undergone the processing in step S13 is compressed by the volume reducer. As a result, the coating of the coated copper wire generates heat, melts, and solidifies. By crushing the solidified coating, the coated copper wire is separated into the copper wire main body and the coating.
[0009]
Next, the process proceeds to step S15. In order to efficiently recover copper and vinyl chloride in the shredder dust, first, the shredder dust is crushed to 10 mm or less (S15).
[0010]
Subsequently, the stainless steel mixed in the crushed material is collected by a stainless steel sorting device (magnetic field strength is preferably 15000 G or more) (S16).
[0011]
Subsequently, the non-ferrous metal mixed in the remaining shredder dust is recovered by a non-ferrous metal separation device (magnetic field strength of preferably 4500 G or more) (S17). As a result, the remaining shredder dust mainly contains copper, vinyl chloride (PVC), and plastics other than PVC.
[0012]
Next, the dust provided with the above treatment is crushed to 3 to 5 mm or less (S18). As a result, a crushed waste home appliance / waste car dust can be obtained.
[0013]
The above-mentioned waste household appliances and waste automobile dust pulverized matter are then processed according to FIG.
[0014]
In FIG. 2, first, processing of specific gravity selection and gate adjustment in step S21 is performed. Here, the dust is divided into a heavy material, an intermediate material, and a light-weight dust (light-weight material) by a general-purpose specific gravity sorting device in the same manner as in the related art. Since this specific gravity sorting device is widely used, it will not be described in detail, but is simply as follows. The dust on the dust support plate is tilted 3 to 4 degrees back and forth, and 4 to 6 degrees left and right. This support plate is provided with a large number of holes of 100 mesh. While vibrating, the wind is applied to the dust support plate almost vertically from below. As a result, the heavy object advances and moves forward, the light object is blown up by the wind and returns backward according to the inclination, and the intermediate object is blown up by the wind and stays at that position. Thereby, the dust is divided into the above three in a state of being arranged in a line. In this operation, the discharge gate is adjusted so as to divide these three components so that the non-ferrous metal does not mix into the lightweight material and the lightweight material does not mix into the heavy material. As a result, the intermediate is a mixture of plastic dust such as hard plastic and rubber having a relatively large specific gravity, and non-ferrous metal dust such as non-ferrous metal (copper fine wire, aluminum, brass, etc.) and glass having a relatively small particle size. It was done.
[0015]
More specifically, the heavy object is a non-ferrous metal such as aluminum or copper, which has a large weight and a large particle size. Here, a small amount of, for example, 1% or less of dust such as plastic is contained. Copper here does not include that obtained from a coated copper wire consisting of a litz wire obtained by twisting thin copper wires used for electrical connection, such as a single thick copper wire for large current. It is like. This weight is directly industrially available, for example, sold as is.
[0016]
The intermediate is composed of a non-ferrous metal having a small particle size, particularly a fine copper wire, and plastic dust such as plastic and rubber having a small particle size mixed therein in an amount of 16 to 20 wt%. Therefore, it cannot be recycled as it is.
[0017]
The three kinds of separated materials obtained as described above are further sent to the next processing step as shown in FIG. That is, the lightweight dust is subjected to volume reduction processing (S27). The heavy object is directly taken out as a non-ferrous metal such as copper or aluminum. As described above, the intermediate product is a mixture of a non-ferrous metal having a small particle diameter such as a fine copper wire and a plastic dust such as plastic and rubber having a small particle diameter. Therefore, as described above, it is impossible to recycle as it is. Therefore, a process of separating the intermediate into the plastic dust and the non-ferrous metal dust is performed. This processing is shown as slaps S22 to S26. That is, the magnetic powder is supplied to and added from the magnetic powder tank to the intermediate (S23), and the mixture is stirred to generate static electricity, and the magnetic powder is attached to the surface of the particles of plastic dust such as plastic and rubber by electrostatic force (S22). ). The magnetic powder preferably has a particle size of 10 μm or less and magnetic properties of about 20 to 200 emu / g. The particle size of the magnetic powder is desirably close to that of the plastic dust. For this reason, when the particle size of the plastic dust is small, it is desirable to use magnetic powder having a small particle size in accordance with the small particle size. According to the experiments of the present inventors, when the diameter of the plastic dust is 5 mm or less and 3 mm or less, the particle diameter of the magnetic powder is set to 5 to 10 μm and 5 μm or less, respectively, as described below. This intermediate can be efficiently separated.
[0018]
Next, it is sieved while being vibrated, and excess magnetic powder excessively attached to the plastic dust is shaken off. At this time, the magnetic powder attached to the surface of the non-ferrous metal is almost shaken off. This is because the surface of the non-ferrous metal is smoother than the above-mentioned plastic dust, the magnetic powder is less likely to adhere thereto, and the non-ferrous metal falls due to slight vibration and impact. Excess magnetic powder is collected from the magnetic powder hopper into its tank and used again (S23). This step S24 aims to increase the purity of the recovered non-ferrous metal by shaking off the magnetic powder attached to the non-ferrous metal as much as possible. According to the experiment of the present inventors, the opening of the sieve is preferably 2 mm or less. When the particle size of the plastic dust is small, it is necessary to make the opening smaller.
[0019]
Next, after the surplus magnetic powder is shaken off in this way, it is sent to the magnetic separator by the quantitative supply device, and the magnetic separator is processed (S26). That is, plastic dust such as plastic and rubber having a low specific gravity is adsorbed and collected integrally with the magnetic powder to which static electricity adheres to the surface. Non-ferrous metals having a large specific gravity are not adsorbed and are collected separately in separate chutes. As the magnetic separator, various types such as a drum type, a suspension type, an electromagnetic type, and a permanent magnet type can be used. Any of these types may be used as long as the plastic dust can be separated from non-ferrous metals such as copper and aluminum. Which type is used depends on the purpose or the content of the processing. The magnetic field strength is preferably about 500 to 4000 G.
[0020]
The plastic dust such as plastic and rubber is reduced in volume in the next stage (S27), and finally is made into RDF. The RDF obtained here is obtained as a copper content as low as possible. Thereby, when this RDF is put into, for example, a furnace, adverse effects on the furnace due to low copper are suppressed as much as possible. The RDF contains iron (magnetite) added earlier. However, the adverse effect of the iron component on the furnace is small. According to the experiment of the inventor, the content of copper in the RDF was 0.5 wt% or less.
[0021]
The non-ferrous metal obtained as a result of step 26 is recycled as it is together with the non-ferrous metal obtained in step S21.
[0022]
Next, the sorting principle of the present invention will be described in more detail.
FIG. 3 shows a state in which the magnetic powders 1, 1,... Adhere to particles of plastic dust 2 such as plastic and rubber. It is considered that the adhesive force is caused by electrostatic force.
[0023]
FIG. 4 is a view for explaining the balance of forces between the particles when the magnet 3 is brought close to the plastic dust 2 to which the magnetic powders 1, 1,... Adhere as shown in FIG. As can be seen from FIG. 4, a downward force of W acts on the dust 2 due to gravity, and a magnetic force w acts on the magnetic powders 1, 1,. The total magnetic force is nw, where n is the number of magnetic powders 1, 1,.... Therefore,
a) No adsorption when W> nw b) Adsorption when W <nw a) applies to non-magnetic metal (non-ferrous metal dust) and b) applies to plastic dust 2 described above. Thus, the plastic dust 2 and the non-ferrous metal dust are separated.
[0024]
FIG. 5 shows the results of the implementation of the present invention. In this example, magnetic powder was added to automobile shredder dust (composition: plastic 11 wt%, rubber 9 wt%, glass 13 wt%, aluminum 30 wt%, copper 37 wt%) crushed to 5 mm or less, and 5 wt% of the total amount of dust was added. After stirring for minutes, the sample was cut out by a vibrating feeder and magnetically separated by a hanging type magnetic separator (magnetic field strength: 1500 G). As a result, plastics and rubbers were obtained at 99.5 wt% or more.
[0025]
On the other hand, in the conventional electrostatic sorting method, the removal rate was limited to 65 to 75 wt% even when the drying treatment was completely performed as the pretreatment.
[0026]
As described above, according to the embodiment of the present invention, the following features can be obtained.
1) The sorting effect does not decrease even for processed products with a wide particle size distribution.
2) It is hardly affected by humidity.
3) Since the magnetic powder does not easily adhere to the nonferrous metal surface (particularly, copper), the purity of the recovery rate is high.
4) When dust is used as a heat source or reducing agent in blast furnaces, converters, electric furnaces, etc., there is no influence of magnetic powder.
5) Inverted sorting method.
[0027]
【The invention's effect】
ADVANTAGE OF THE INVENTION According to this invention, the shredder dust of industrial wastes, such as a waste electric appliance and a waste car, can be fractionated according to a composition.
[Brief description of the drawings]
FIG. 1 is a processing flow showing a part of processing according to an embodiment of the present invention.
FIG. 2 is a processing flow following the figure.
FIG. 3 is an explanatory view showing a sorting principle of the present invention.
FIG. 4 is an explanatory diagram showing a sorting principle of the present invention.
FIG. 5 is a graph showing the results of an experiment performed to confirm the effects of the present invention.

Claims (5)

Take out a mixture of non-ferrous metal dust containing at least non-ferrous metal and plastic dust containing at least plastic from shredder dust of industrial waste such as waste household appliances and end-of-life vehicles. The magnetic dust is caused to adhere to the surface of the plastic dust by the electrostatic force, and the plastic dust to which the magnetic powder is attached and the non-ferrous metal are separated by magnetic separation to thereby produce the plastic dust. And a non-ferrous metal. By specific gravity sorting from the shredder dust, to remove lightweight dust mainly composed of plastic and heavy particles having large particle diameter mainly composed of non-ferrous metal, non-ferrous metal having small particle diameter such as copper fine wire, at least small particle diameter The shredder dust sorting method according to claim 1, wherein an intermediate mainly composed of a mixture with plastic is obtained as the mixture. 3. The shredder dust sorter according to claim 1, wherein, prior to the magnetic sort process, a process of removing excess magnetic powder attached to the plastic dust in the magnetic powder is performed. 4. Method. The method according to claim 1, wherein the magnetic powder has a particle diameter of 10 μm or less and a magnetic property of 20 to 200 emu / g. 5. 5. The magnetic powder according to claim 1, wherein when the shredder dust is 5 mm or less, 3 mm or more, and 3 mm or less, the magnetic powder is 5 to 10 μm and 5 μm or less, respectively. Shredder dust sorting method.

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