JP2001116226A - Method of recycling shredder dust - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively utilize shredder dust as a carburizing material or preheating material for a melting furnace for manufacturing steel by securely eliminating wire harness. SOLUTION: Shredder dust is ground and then classified into heavy dust and light one by a wind force classifier, wire harness being contained in the shredder dust is included into the heavy dust for elimination, and at the same time the light dust is subjected to volume reduction and solidification for utilizing the same as the raw material and fuel of a melting furnace for manufacturing steel.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recycling shredder dust, and more particularly, to a method for producing steel such as an arc furnace or a converter by removing a wire harness which is largely contained in shredder dust obtained by cutting and crushing a scrap car. The present invention relates to a method for recycling shredder dust used in a melting furnace.

[0002]

2. Description of the Related Art Shredder dust has been mostly landfilled in the past, but landfill disposal is limited due to the recent tightness of landfill sites and the risk of environmental pollution. Therefore, for example, in Japanese Patent Laid-Open No. 5-116441, dust containing small pieces of plastics and rubbers is charged into the bottom of a bucket for charging scraps, and the top thereof is covered with lime or iron scrap. There has been proposed a method of treating shredder dust which is introduced into a container and treated.

[0003]

However, shredder dust from end-of-life vehicles and the like contains a large amount of wire harness which is a plastic-coated electric wire having copper as a core wire. There is a problem that the copper content of the molten steel in the melting furnace for production becomes excessively large and the quality is deteriorated.

Further, when shredder dust mainly composed of plastics or the like is injected into the above-mentioned arc furnace at once, gasification and combustion are performed at once in a short time. In addition to the problem of poor reaction efficiency, a large amount of unburned gas is generated at one time, so it cannot be burned in the secondary combustion chamber provided at the latter stage of the arc furnace, and harmful gas is generated in the exhaust system, Could explode.

Therefore, the present invention solves such a problem. The first object of the present invention is to remove a wire harness without fail and to effectively use shredder dust as a carburizing material or a preheating material for a melting furnace for steel making. An object of the present invention is to provide a method for recycling shredder dust that can be used. Further, a second object of the present invention is to provide a method for recycling shredder dust capable of improving the heat transfer efficiency to iron scrap and the reaction efficiency with molten steel when the shredder dust is reused as a carburizing material or a preheating material. Is to provide.

[0006]

Means for Solving the Problems In order to achieve the above object, the first aspect of the present invention is to shred shredder dust, and then sort the shredder dust into heavy dust and light dust using a wind separator, and to shred the shredder dust. The contained wire harness is removed from the heavy dust, and the light dust is reduced in volume and solidified and used as a raw material and fuel for a melting furnace for steel production.

In the first invention, since the wire harness is removed from the light-weight dust, the wire harness is put into a melting furnace for steel making such as an electric furnace and reused as a preheating material or a carburizing material. Also, the copper content in the molten steel does not become excessive.
In addition, since bulky lightweight material dust is reduced in volume to a solid shape, it does not become a suspended state during handling, etc., it is easy to handle, and sudden gas generation occurs when thrown into the melting furnace. Does not occur. further,
Since the wire harness is removed, the wire harness is not clogged or entangled in the volume reduction and solidification machine, and there is no trouble such as breakage of the compression screw.

In the second aspect of the present invention, the heavy dust obtained by the above-mentioned wind separation is further subjected to water specific gravity separation to remove the wire harness as sediment, and the suspended matter at the time of the water specific separation is reduced in volume together with the above-mentioned lightweight dust. It is solidified and used as a raw material and fuel for a melting furnace for steel production.

In the second aspect of the present invention, in addition to the light-weight material dust obtained by the wind power separation, the light-weight material dust is collected by performing the water specific gravity separation, so that the recycling rate of the shredder dust to the melting furnace for steel production can be reduced. It can be further improved.

[0010] In the third aspect of the present invention, the heavy dust obtained by the above-mentioned wind sorting is further supplied to a rotary wind sorting machine having a rotating drum provided with a raking plate, and a wire harness is extracted from the heavy dust. In addition to separating, the wind-screened light-weight dust and the rotary wind-screened light-weight dust are reduced in volume and solidified, and used as a raw material and fuel for a melting furnace for steel production.

In the third aspect of the present invention, the light-weight dust from the rotary wind separator is reduced in volume and solidified together with the light-weight dust from the wind separator, so that the recovery rate from the shredder dust to the reduced-solidified material is improved. I do. Also, in the rotating drum of the rotary wind separator, since the wire harnesses in the heavy dust are entangled with each other to form a bird's nest, only the wire harness can be separated from the heavy dust, and the wire peeling machine removes the wire harness. Separate the harness into cladding and copper wire,
The copper wire can be reused as a reinforcing material for aluminum casting. As a result, the recycling rate of shredder dust can be further improved as a whole.

In the fourth aspect of the present invention, when the light-weight dust and suspended matter are reduced in volume and solidified, they are formed into a plurality of types of solidified groups having different average values of specific surface area or density, and the solidified groups are mixed. Used as a raw material and fuel for melting furnaces for steel production.

The light-weight dust and suspended matter are made of thin plastics, urethane foam, fiber, rubber, etc., and have a carbon content of about 50% and a low calorific value of 4000 to 70.
Since it is 00Kcal / Kg, as described above,
Alternatively, it can be used as a preheat source for iron scrap by gasification combustion. Here, in the fourth invention, during volume reduction and solidification, a plurality of types of solidified products having different average values of specific surface areas or densities are formed, mixed at an appropriate ratio, and introduced into a furnace of a steelmaking manufacturing melting furnace. Since the combustion rates of the solidified materials are different from each other, combustion and gasification in the furnace do not proceed at one time. Therefore, the contact time with the furnace contents becomes longer as a whole, and the preheating efficiency when preheating the iron scrap and the reaction efficiency with the molten metal are greatly improved. Further, since a large amount of unburned gas is not generated at one time, the combustion of the unburned gas can be completed in a secondary combustion tower or the like provided in the exhaust system of the melting furnace. There is no danger of generation or explosion of unburned gas.

[0014]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS (First Embodiment) In FIG.
The shredder dust is crushed into small pieces having a maximum dimension of 25 mm or less by a crushing machine such as a horizontal hammer mill (step 1), and subsequently separated into heavy dust and lightweight dust by a vertical duct type wind separator or the like (step 1). Step 2).
The vertical duct-type wind separator sorts the objects to be sorted from above the duct while sending air from below the duct, and allows the lightweight ones to be entrained in the airflow and collected by the subsequent cyclone separator or bag filter. On the other hand, heavy objects fall under the duct under their own weight and are collected. At this time, the ventilation R
When the number e is set to about 10,000, the wire harness contained in the shredder dust contains iron, copper,
Separated and sorted as heavy dust along with metals such as aluminum, glass, earth and sand, and hard plastic. The selected wire harnesses are disposed of in landfill.

After the wire harness or the like is separated and removed by the above-mentioned wind separator, the lightweight dust made of fiber, paper, rubber, soft plastic, urethane foam, or the like is heated to 150 ° C. by a twin-screw volume reducing solidifier or the like. The mixture is heated and compressed to the extent that the volume is reduced and solidified (step 3). Then, the continuous solidified product output from the volume reduction solidifying machine is cut into an appropriate size by a cutter to obtain a columnar solidified material having a diameter of, for example, 50 mm and a length of about 100 mm. The copper content of this solidified product is 0.1.
The content is 5% by weight or less. Therefore, even if this is put into a melting furnace for steel production such as an electric furnace and reused as a preheating material or a carburizing material, the copper content in the molten steel does not become excessive. And, as it is, light and bulky dust having a bulk specific gravity of about 0.1 to 0.3 is reduced in volume to a solid shape, so that there is no problem such as a shelf hanging state during handling, and Is easy. In addition, since the wire harness has been removed, when performing volume reduction and solidification by heating, compression, and molding, the wire harness is not clogged or entangled in the volume reduction and solidification machine, and the compression screw is damaged. There is no problem such as doing. In addition, the recycling rate of shredder dust in this embodiment is about 70%.

(Second Embodiment) In FIG. 2, after the shredder dust is crushed into small pieces having a maximum size of 25 mm or less by a crusher such as a horizontal hammer mill (step 1).
0), input to a quantitative feeder such as a vibration feeder (Step 20), and is quantitatively supplied to a vertical duct-type wind sorter similar to the first embodiment (Step 30). The use of the fixed-quantity feeder does not significantly change the amount of dust supplied to the wind separator, so that one of the heavy dust and the light dust is prevented from entraining with the other and the sorting efficiency is improved. .

At this time, if the ventilation Re number of the air volume sorter is set to about 10,000 similarly to the first embodiment, the wire harness contained in the shredder dust is made of iron, copper, aluminum or the like. It is sorted as heavy dust along with metals, glass and earth and sand. Then, the heavy dust is further sent to the water-specific gravity separator (step 40). In the water specific gravity sorter, the wire harness is sorted out as a sediment together with metals, glass and earth and sand, and this is disposed of by landfill. At this time, the light-weight dust accompanying the heavy-weight dust is separated as a floating substance.

The light-weight dust from the wind separator and the suspended matter from the water specific gravity separator are heated and compressed at a heating temperature of about 150 ° C. by a two-shaft type volume-reducing and solidifying machine similar to the first embodiment to reduce the volume. Then, it is cut into an appropriate size by a cutter (step 50) to obtain a columnar solid. This solidified material is reused in a steelmaking melting furnace such as a converter, and has the same effect as the first embodiment. In particular, in this embodiment, since the water specific gravity sorting is performed in addition to the wind sorting of the first embodiment, the copper content in the columnar solidified material is stabilized at a low level, and the recycling rate from shredder dust is also 80%. Improve to the extent.

(Third Embodiment) In FIG. 3, the shredder dust is crushed into small pieces having a maximum size of 25 mm or less by a crusher such as a horizontal hammer mill (step 10).
1) If necessary, a magnetic separator is used (step 10)
2) Useful metals are recovered. Subsequently, it is input to a quantitative feeder such as a vibrating feeder (step 103), and is fed quantitatively to a vertical zigzag type wind separator having the same principle as the first embodiment (step 104).

When the number of ventilation Re of the wind separator is set to about 10,000 similarly to the first embodiment, the wire harness contained in the shredder dust is made of metal such as irons, coppers, and aluminum. It is dropped and sorted as heavy dust together with glass and earth and sand, and the heavy dust is sent to a rotary wind sorter described later (step 108).

FIG. 4 shows a schematic configuration of a rotary wind separator 6 and a vibrating sieve 7 provided at a stage subsequent thereto. The rotary wind separator 6 has a rotary drum 61 whose both ends are open, and a plurality of raking plates 65 are provided on the inner periphery of the rotary drum 61 at intervals in the circumferential direction. Rotating drum 61
When the heavy dust from the first and second wind separators is supplied into the rotating drum 61 while being blown from one end of the wire harness, the wire harnesses become entangled with each other in the process of being scooped, forming a bird's nest, and together with the heavy dust. The rotating drum 61 is dropped and discharged from the other end onto the sieving machine 7 (Step 10 in FIG. 3).
8, 109). Light-weight dust is carried to the cyclone separator 62 by blowing air when it is scooped, and most of the light-weight dust is collected there, and finer light-weight dust is collected by the bag filter 63 in the subsequent stage. Note that a blower 64 is provided downstream of the bag filter 63. In the sieving machine 7, heavy dust having a predetermined size or less output from the rotary wind separator 6 is dropped and discharged downward. Further, the wire harness 71 entangled in a bird's nest shape is discharged along the sieving machine 7.

In FIG. 3, the light-weight dust collected by the rotary wind separator 6 is input to the fixed-quantity feeder together with the light-weight dust from the wind separator (step 105) to the first and second volume reduction solidifiers. A fixed amount is supplied (steps 106 and 10
7). By quantitatively supplying the light-weight dust to each volume-reducing solidifier, the control and management of the density of the generated solidified material are facilitated. In the first volume reduction and solidification machine, light-weight dust is heated and compressed at about 150 ° C. and extruded, and then, for example, has a diameter of 3 with a cutter.
It is cut into a group of solidified solids (small solidified material) having an average value of 0 mmφ and a length of about 60 mm. It is cut into a columnar solidified group (solidified large) having an average value.

The small solidified material, the large solidified material, and the heavy dust from the sieving machine are used as a preheating material or a carburizing material for an arc furnace. In this case, the small solidified material and the large solidified material differ greatly in their specific surface areas, so their combustion rates are different from each other. When these solidified materials are mixed appropriately and put into an arc furnace, combustion and gasification proceed at once. Therefore, the contact time with iron scrap or molten steel is prolonged, and the preheating efficiency of iron scrap and the reaction efficiency with molten steel are greatly improved. Further, since a large amount of unburned gas is not generated at one time, there is no danger of generating harmful gas in the exhaust system of the arc furnace or explosion of unburned gas.

The wire harness 71 (FIG. 4) discharged from the sieving machine 7 is separated into a covering material and a copper wire by a peeling machine (step 110), and the copper wire is reused as a reinforcing material of an aluminum casting. The coating is landfilled. The usage rate of the shredder dust in the present embodiment is 9% because the wire harness alone is selected and the copper wire is reused by rotating wind sorting and subsequent sieving.
5% or more.

In each of the above embodiments, crushing and wind separation may be performed in two or more stages.
In the second and subsequent stages, it is also possible to perform only the wind sorting without crushing.

[0026]

As described above, according to the present invention, by reliably removing the wire harness, the shredder dust can be effectively used as a carburizing material or a preheating material for a melting furnace for steel making, and the carburizing can be carried out. When shredder dust is reused as a material or the like, the efficiency of heat transfer to iron scrap and the efficiency of reaction with molten steel can be improved.

[Brief description of the drawings]

FIG. 1 is a flowchart illustrating a shredder dust recycling method according to a first embodiment of the present invention.

FIG. 2 is a flowchart of a shredder dust recycling method according to a second embodiment of the present invention.

FIG. 3 is a flowchart illustrating a shredder dust recycling method according to a third embodiment of the present invention.

FIG. 4 is a view showing a schematic configuration of a rotary wind separator and a vibrating sieve.

[Explanation of symbols]

Reference numeral 6: rotary wind separator, 61: rotary drum, 62: cyclone separator, 63: bag filter, 65: scraping plate, 7: sieving machine, 71: wire harness.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) B09B 5/00 ZAB C21C 5/28 Z 4K002 C10L 5/48 ZAB 5/52 4K014 C21C 5/28 F23G 5 / 02 ZABE 5/52 7/00 ZABB F23G 5/02 ZAB B09B 5/00 Q 7/00 ZAB ZABC F term (reference) 3K061 AA23 AB03 AC20 BA01 DA02 3K065 AA23 AB03 AC20 BA01 4D004 AA28 BA03 CA05 CA03 CA08 4D021 FA03 FA06 GA08 GA21 GA29 GB03 GB10 HA01 4H015 AA02 AA17 AB01 BA08 BA11 BA13 BB01 BB05 CB01 4K002 AB10 4K014 CB03 CB05 CB09

Claims (4)

[Claims] After crushing the shredder dust, the shredder dust is separated into heavy dust and light dust by a wind separator, and a wire harness included in the shredder dust is removed and included in the heavy dust. A method of recycling shredder dust, comprising reducing and solidifying the light-weight dust and using it as a raw material and fuel for a melting furnace for steelmaking. 2. The heavy dust obtained by the wind separation is further subjected to water specific gravity separation to remove the wire harness as sediment, and the suspended matter at the time of water specific gravity separation is reduced in volume and solidified together with the light weight dust. The method for recycling shredder dust according to claim 1, wherein the shredder dust is used as a raw material and a fuel for a melting furnace for steel production. 3. The heavy dust obtained by the wind sorting is further supplied to a rotary wind sorter having a rotating drum provided with a raking plate therein to separate a wire harness from the heavy dust, The method for recycling shredder dust according to claim 1, wherein the light-weight dust and the light-weight dust selected by a rotary wind are reduced in volume and solidified and used as a raw material and a fuel for a melting furnace for steel production. 4. A method for reducing and solidifying the light-weight dust and suspended matter into a plurality of solidified groups having different average values of specific surface area or density, and mixing the solidified groups to form a melt for steel production. The method for recycling shredder dust according to any one of claims 1 to 3, which is used as a raw material and a fuel for a furnace.