JP2012219364A - Method for producing subsidiary material for steel - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a subsidiary material for steel for stably obtaining a subsidiary material for steel having excellent strength and magnetic force transportability compared with the conventional art, when the subsidiary material for steel is produced for the purpose of recycling shredder dust.SOLUTION: In the method for producing the subsidiary material for steel, polymer crushed dust and inorganic fine powder dust sorted and recovered from the shredder dust are mixed, and thereafter, the mixture is subjected to melt extrusion molding to produce the subsidiary material. The polymer crushed dust includes a porous material, further, the inorganic fine powder dust includes iron fine powder or iron oxide fine powder, and the polymer crushed dust and the inorganic fine powder dust are dusted and mixed, and thereafter, the melt extrusion molding is performed.

Description

  The present invention relates to a method for producing a secondary material for steel that is suitable for recycling shredder dust and inorganic fine powder dust.

Here, automotive shredder residue as shredder dust (ASR: A utomobile S hredder R esidues) will be described as an example.

  ASR is the waste that remains after removing valuable materials from shredder dust generated by crushing scrap automobiles that have removed "fluorocarbons" that destroy the ozone layer and "airbags" that can explode. It is. According to the Automobile Recycling Law, which came into effect from January 2005, these "CFCs", "Airbags" and "ASR" are obliged to be recycled by automakers.

  For this reason, development of the technique which recycles ASR is requested | required, for example, the method of using effectively as a secondary material for steel is proposed by patent document 1 * 2.

  Patent Document 1 states that “in a method of charging shredder dust into a metal melting furnace and mixing shredder dust and molten or semi-molten plastic waste, press the mixture, A processing method for shredder dust, characterized in that the molded product is charged into a metal melting furnace ”(see claim 1).

  Paragraph 0007 states that “Plastic waste materials, such as plastic waste materials, preferably those crushed to a particle size of 50 mm or less, and powdered metal waste materials, such as pickled sludge, are crushed by drying. It is preferable to quantitatively supply metal scraps, grinding scraps, etc. to a rotary kiln to melt or semi-melt the plastic waste material.Plastic waste material, preferably one crushed to a particle size of 50 mm or less. While supplying quantitatively to the rotary kiln, supplying the powdered metal waste material to the rotary kiln, and indirectly heating, the plastic waste material becomes molten or semi-molten, and the powdered metal waste material adheres to the surface, Since the surface is coated with the powdered metal waste material, the plastic waste is placed in the rotary kiln. Without melting or semi-molten material in stays attached, it is indeed described as convenient. ".

  However, the “powder metal waste material” does not disclose or suggest the “inorganic fine dust” of the present invention. The “powder metal waste material” of Patent Document 1 is blended for preventing adhesion of molten plastic in a rotary kiln (rotary furnace). On the other hand, in the present invention, the “inorganic fine powder dust” is blended for adjusting the specific gravity of the extruded product, and the adhesion to the polymer crushed dust is not caused by melting, but is porous. This is due to adsorption (entrance) to the material.

On the other hand, Patent Document 2 states that “a method of putting shredder dust into a steelmaking electric furnace and reusing it as a heat source for a steelmaking electric furnace, selecting and processing resins from the shredder dust and collecting them; A step of mixing the recovered resins and irons;
A step of forming a steelmaking raw fuel element by heating and compressing the mixed mixture, and a step of introducing the formed steelmaking raw fuel element into an electric furnace. ) A method for reusing shredder dust, wherein the ratio of resins and irons is adjusted so that the density is 1.5 to 2.5 t / m ³ . Is proposed (see claim 1 etc.).

  However, “irons” in Patent Document 2 are intended to be “strips or linear bodies” such as “iron scraps (for example, press scraps)”. That is, Patent Document 2 does not actively plan that the “irons” of the present invention adhere (enter) through the pores (surface pores) of the porous material.

  Therefore, in Patent Document 2, uniform dispersion of irons cannot be expected, and the strength and stability of magnetic conveyance in the present invention cannot be expected.

  On the other hand, in iron product processing such as shot peening, shot blasting, and polishing, a large amount of iron powder is generated. And they are collected as dust collection dust together with other inorganic powders, but the use of dust collection dust is limited to eco-cement raw materials etc., and most of them are solidified with a binder such as cement and discarded. It was the current situation.

JP-A-2005-812 JP 2007-21445 A

  In view of the above, the present invention stably obtains a secondary material for steel that is more excellent in strength and magnetic force transportability than the conventional one when manufacturing the secondary material for steel for the purpose of recycling shredder dust. An object of the present invention is to provide a method for producing a secondary material for steel.

  In the process of diligently developing to solve the above-mentioned problems, the inventors of the present invention have a high molecular weight crushing dust collected and collected from ASR, which has a content ratio of “a porous material having countless surface pores”. Focused on high. This is because most of the automobile interior parts are made of a polymer foam (sponge) such as urethane foam or a nonwoven fabric. And if the coating mixture prepared by coating and mixing the iron dust collection dust (inorganic fine powder dust) generated in the shot blasting and the like to this is extruded, Knowing that a molded product (secondary material for steel) in which iron powder and the like are uniformly dispersed can be obtained, the inventors have come up with a method for manufacturing a second material for steel having the following configuration. As a result, the secondary material for steel of the present invention is superior to conventional products in strength and also excellent in magnetic material transportability, and the handleability (including storage properties) is improved.

This is a method for manufacturing secondary materials for steel, which is produced by mixing polymer fine-pulverized dust collected from the lighter material side with inorganic fine powder dust after at least one specific gravity difference selection from shredder dust and then melt-extrusion molding. And
The polymer crushed dust is a low specific gravity polymer crushed dust containing a porous material and having a specific gravity of 0.8 or less, and the inorganic fine powder dust contains iron fine powder or iron oxide fine powder.
The low specific gravity polymer coarse dust and the inorganic fine powder dust are coated (mabushi) and mixed, and then the melt extrusion molding is performed.

  And it is desirable that the above-mentioned specific gravity difference sorting is normally performed by wind sorting using floating or sinking. The device is simple and requires little sorting power. As specific gravity difference sorting, it is also possible to use centrifugation, electrostatic separation or the like.

  The porous material is a polymer foam and / or a polymer nonwoven fabric.

  The above-mentioned low specific gravity polymer coarsely pulverized dust is obtained by crushing the first-classified lightweight material selected by primary specific gravity difference, and further selecting secondary specific gravity difference to remove rubber, hard plastic, etc., so that the specific gravity is 0.5 or less. It is desirable to be the next sorted light weight.

  Therefore, it can be expected that the ratio of the porous material is increased and the efficiency of coating and mixing (uniform mixing) with the inorganic fine powder dust is improved.

  It is desirable that the low specific gravity polymer crushed dust is obtained by removing the secondary sorted light-weight material and further removing earth and sand, glass fine powder and the like with a roll screen. If the low specific gravity polymer coarse dust contains earth and sand / glass fine powder, during coating and mixing, the earth and sand fine glass will block the pores of the low specific gravity polymer coarse dust, resulting in iron fine powder and iron oxide fine powder. May be prevented from entering the pores.

  Usually, it is desirable that the low specific gravity polymer coarsely pulverized dust is obtained by removing iron powder with a magnetic separator after crushing to a size of 50 mm or less.

  The low specific gravity polymer crushed dust is better in coating and mixing with the inorganic fine powder dust when the size is uniform, and the one with the iron piece removed is the porous material clogged with the iron piece. The pores are opened, and the coating and mixing properties of the inorganic fine powder dust and the polymer coarse dust are improved. Further, if iron pieces are mixed into the extrusion molding machine, the molding machine is damaged and excessively worn.

  And in each said manufacturing method, the mixing ratio of the said polymer ground material and the said inorganic fine powder dust is adjusted, and the extrusion molding of specific gravity 1.3-3.0 (desirably 1.5-2.5) is carried out. It is desirable to manufacture by melt extrusion. If the extruded product is cut into a predetermined length, a sedative material, a homing suppressing material, a carburized material, or the like can be easily obtained.

  In each of the above-described configurations, it is desirable that the low specific gravity polymer coarse dust is ASR-derived low specific gravity ASR. This is because ASR contains many porous materials such as urethane foam and nonwoven fabric.

  In each of the above-mentioned configurations, it is desirable that the inorganic fine powder dust originates from iron product processing such as shot peening, shot blasting, and polishing. Inorganic fine powder dust derived from iron product processing is mostly iron powder and iron oxide powder, and when used as a secondary material for steel, it is advantageous as an iron source, easily obtains magnetic force, and further, other inorganic powder ( Compared to Cu, Al, etc.), the specific gravity is high and the specific gravity can be easily prepared (high specific gravity can be easily obtained).

  In each of the above manufacturing methods, a large number of rectangular paddles project in the radial direction at predetermined intervals along the spiral of a predetermined lead from the peripheral surfaces of two parallel horizontal rotation shafts. It is preferable to use a coating and mixing apparatus in which the paddle surface of each paddle is along the spiral.

  The horizontal stirrer configured as described above does not partially melt the finely divided polymer dust of the inorganic fine powder dust, and facilitates coating and mixing of the fine inorganic powder dust and the finely divided polymer dust.

  The sub-material for steel having a desirable configuration manufactured by the method for manufacturing the sub-material for steel of the present invention is as follows.

  An inorganic fine powder dust substantially composed of iron powder and / or iron oxide is combined with a melt of low specific gravity polymer coarse dust having a specific gravity of 0.8 or less, and a specific gravity of 1.3 to 3.0 (preferably 1.5 to 2.5), which is an extruded molded product.

It is a flowchart which obtains the low specific gravity polymer crushed dust (low specific gravity ASR) used as the raw material of this invention through a shredder, a selection process, etc. from a waste automobile body. It is a flowchart which extrudes after coating and mixing with low specific gravity ASR and inorganic fine powder dust (iron powder). FIG. 3 is a flowchart showing the apparatus of FIG. 2. FIG. 2 is a plan view of a coating and mixing apparatus suitable for coating and mixing low specific gravity polymer dust and inorganic fine powder, and a perspective view of essential parts of a stirring unit (mixing unit).

  Hereinafter, an embodiment of the present invention will be described in detail. Here, the case where it is derived from ASR as the shredder dust used as the raw material for the polymer crushed dust will be described. However, the shredder dust such as waste home appliances having a high component ratio such as foam and nonwoven fabric is also used for the polymer crushed powder of the present invention. It can be used as a raw material for dust. Furthermore, the end material (trimming material) which is a kind of shredder dust generated by processing a foam product or a nonwoven fabric can also be used as a raw material for the polymer crushed dust.

  A. First, the flow of obtaining low specific gravity polymer crushed dust (low specific gravity ASR), which is a raw material of the present invention, through a shredder / sorting process etc. from a discarded automobile body will be described with reference to FIGS.

  (1) A scrap car 12 is roughly crushed with a pre-shredder 12 to obtain a crushed material from a scrap car that has been delivered.

  (2) The crushed material obtained in the above (1) is crushed with a shredder machine (for example, hammer type) 14 until it passes through a screen (for example, 60 mm × 120 mm).

  The dust generated by the shredder machine 14 is collected by the first cyclone (dust collector) 16 as lightweight fine dust (polymer / inorganic fine dust).

  (3) The crushed material (shredder dust) discharged from the shredder machine 14 is subjected to a primary sorting weight ASR (primary sorting heavy material) and a primary sorting light weight ASR (primary sorting light weight) by a blow-up sorter (primary wind sorter) 18. And primary wind sorting.

For example, when passing over a perforated plate (combination plate of a porous plate with a hole diameter of Φ6 mm and a porous plate with a hole diameter of Φ2 mm, arranged in the same length and back and forth), wind is sent from below the perforated plate to float Is collected from the upper part by a second cyclone (second dust collector) 20 and collected as a primary sorting light weight ASR, and a non-floating thing is collected as a primary sorting weight ASR. Their composition is as follows.
Primary sorting weight ASR: Metal pieces, glass pieces / solid rubber, hard plastic, etc.
Primary selection lightweight ASR: Low specific gravity plastic (PP, low density PE), foamed plastic (foamed urethane), high foamed rubber, non-woven fabric, etc.

  (4) The first-sorted lightweight ASR selected above is crushed (crushed) to 80 mm or less (preferably 50 mm or less) with a uniaxial crusher (crusher) 22. And it classifies with the sieve sorter 24 into 3 types (large, medium, and small) of more than 50 mm, 15-50 mm, and less than 15 mm. This is for recovering as much material as possible and making the subsequent process easier by making the size of the coarsely crushed material uniform.

  A classified product of less than 15 mm may be disposed as dust, but may be recycled as a homing suppression material. Since the homing suppression material places importance on the specific gravity, even if earth and sand and glass are mixed, it can be made into a slag by a steel manufacturer and commercialized.

  (5) And, for two types of more than 50 mm (large), 15-50 mm (medium), the secondary sorting weight ASR (secondary sorting heavy article) and the secondary sorting lightweight ASR (secondary sorting lightweight article) again In addition, secondary wind sorting is performed using the secondary wind sorters 26 and 26. This is because the ratio of the porous material in the low specific gravity ASR used in the present invention is increased as much as possible.

Note that the secondary sorted lightweight ASR subjected to the secondary wind sorting is collected by the third and fourth cyclones 28 and 30 as described above. Their composition is as follows.
Secondary sorting weight ASR (high specific gravity ASR): Hard plastic, wire harness, etc.
Secondary sorting lightweight ASR (low specific gravity ASR) ... porous plastic (urethane foam), non-woven fabric, etc.

  (6) The low specific gravity ASR collected in the first, third, and fourth cyclones (dust collectors) 16, 28, and 30 includes earth and sand and fine glass powder. These soil and glass fine powders may cause problems in the subsequent mixing and forming process as described above.

  For this reason, dust such as earth and sand and glass is removed from the low specific gravity ASR from the first, third and fourth cyclones 16, 28 and 30 by the roll screen 32. The roll screen 32 has a mechanism in which a triangular rice ball-shaped roll rotates in the traveling direction of the load and drops earth, sand, glass, and the like from a gap between the shaft connecting the rolls and the tip of the rice ball-shaped roll.

  Thus, the low specific gravity ASR that is the raw material of the present invention is recovered. Here, the low specific gravity is a bulk specific gravity (apparent specific gravity) of 0.8 or less, preferably 0.5 or less, and more preferably 0.2 or less. If it exceeds 0.8, the ratio of the porosity becomes small, the iron powder is difficult to be uniformly dispersed, it is difficult to obtain a secondary material for steel that is excellent in strength and excellent in magnetic force transportability.

  (7) The high specific gravity ASR collected by the primary wind sorter 18 includes iron, rubber, non-ferrous metal, glass, soil, and the like. For this reason, iron scraps are sorted and collected using the magnetic separator 25. The rest is recovered as a high specific gravity ASR together with the high specific gravity ASR from the secondary wind sorter 26. These high specific gravity ASRs include wire harnesses and solid plastics in addition to the rubber, non-ferrous metal, glass, and earth, and can be made into slag and commercialized by steel manufacturers.

  B. The low specific gravity ASR selected and collected as described above (for example, specific gravity of 0.5 or less) is mixed (coated and kneaded) with inorganic fine powder dust containing iron fine powder or iron oxide fine powder, and then extruded.

  As the inorganic fine powder dust, it is desirable to use those derived from processing of iron products such as shot peening, shot blasting, and polishing because the content of iron fine powder and iron oxide fine powder is high.

  The low specific gravity ASR is again pre-treated after coarsely pulverizing (for example, 50 mm) with a pulverizer (uniaxial pulverizer) 36 and then collecting (removing) iron powder with a suspended magnetic separator (magnetic separator) 38. It is desirable to keep it. This is to prevent damage and excessive wear of the equipment during coating and mixing of the low specific gravity ASR and inorganic fine dust.

  As shown in FIG. 4, the coating and mixing device 40 includes a large number of rectangular paddles 45 at predetermined intervals along the spiral of predetermined leads from the peripheral surfaces of the two parallel rotating shafts 42 and 42. A configuration in which the paddle surface 45a of each paddle 45 is arranged so as to extend in the radial direction and is along the spiral is desirable. Specifically, for example, the shaft distance is 410 mm, the lead is 600 mm, the rotation shaft diameter is 180 mm, the paddle rotation outer diameter is 520 mm, and the paddle size is 120 mm and the length is 165 mm.

  In the coating and mixing apparatus 40 having the above-described configuration, the shearing force hardly acts on the low specific gravity ASR, and the inorganic powder dust is scraped up together with the inorganic fine powder while being floated by the paddle between the two axes. For this reason, the inorganic fine powder dust adheres (enters) well on the porous surface of the low specific gravity ASR, and the coating efficiency is improved.

  In the case of the coating and mixing device 40, the low specific gravity ASR is supplied from the first fixed amount feeder 46 and the inorganic fine powder dust is supplied from the second fixed amount feeder 48 to the raw material inlet 50 of the coating and mixing device 40, respectively. By driving the rotating shafts 42, 42 of the coating and mixing device 40 with a pulley 54 with the activated electric motor 52, the inorganic powder dust is applied to the low specific gravity ASR and sent to the discharge port 56 side while being mixed. Mix.

  Here, the mixing ratio of the low specific gravity ASR and the inorganic fine powder dust differs depending on the type of the required auxiliary material for steel. Usually, the specific gravity is adjusted to 1.0 or more (desirably 1.3 or more, more desirably 1.5 or more).

  For example, the mixing ratio of both is inorganic fine dust / low specific gravity ASR (mass ratio) = 5/95 to 80/20 (preferably 60/40 to 80/20). Regardless of whether the low specific gravity ASR is excessive or insufficient, it is difficult to obtain a secondary material for steel that is excellent in strength and excellent in magnetic transportability.

  Then, the mixture prepared above is used as a raw material and melted and solidified by extrusion molding with an extruder (for example, a biaxial extruder) 58. At this time, as the extruder 58, a general-purpose plastic extruder can be used. The die plate temperature varies depending on the type of raw material. For example, when the raw material has a low specific gravity ASR, the die plate temperature is set in the range of 180 to 200 ° C.

  The diameter of the extruded product at this time is appropriately set, for example, in the range of 15 to 120 mm (desirably 20 to 50 mm) according to the type of the auxiliary material for steel.

  Usually, since an extrusion molding is high temperature, it cuts into length (for example, 30-200 mm) suitably, is water-cooled with the cooling shower 59 etc. (illustration example), is dropped in water in the water tank 60, and water is put on the solid surface. Solidified by forced air cooling in the attached state. This is because if the air-cooling is allowed to stand at a high temperature, the cut extrudate (secondary material for steel) is deformed or mutually fused during the air-cooling.

  The sub-material for steel produced in this way has excellent strength and excellent magnetic transportability, and can also be used as a sedative material, a homing suppression material, a carburizing material, and a heat source (fuel) for an electric furnace.

  Apply low-density ASR dust (bulk specific gravity: 0.2) and iron powder dust (bulk specific gravity: 2.5) as the former / the latter ≒ 8/2 using the coating and mixing apparatus as described above. After mixing, extrusion was performed at a die plate set temperature (190 ± 5 ° C.) using a twin screw extruder (nozzle hole diameter: 30 mm, extrusion screw diameter: 600 mm, length: 250 mm), and then cut to a length of about 80 mm. . The cut material was dropped in water to be cooled and solidified to produce a sedative material (about 30 mmΦ × 80 mmL).

  The appearance of the soothing material was a graphite color and a smooth surface. The specific gravity was 1.40 ± 1.0.

And the result of having conducted component analysis was as follows.
Moisture 1.14%
75.7% ash
Chlorine 1.43%
Sulfur Less than 0.01%
Nitrogen 1.73%
Iron (Fe) 20%

  The calorimeter measures the high calorific value, and the low calorific value obtained by subtracting the latent heat of vaporization based on the moisture is about 5000 cal / g, which is sufficient not only as a soothing material but also as a carburizing material and fuel. It was confirmed that it could be used.

DESCRIPTION OF SYMBOLS 12 Pre-shredder 14 Shredder machine 18 Primary wind sorter 26 Secondary wind sorter 40 Coating mixing device 46 1st fixed supply machine 48 2nd fixed supply machine 58 Extruder

Claims (13)

This is a method for manufacturing secondary materials for steel, which is produced by mixing polymer fine-pulverized dust collected from the lighter material side with inorganic fine powder dust after at least one specific gravity difference selection from shredder dust and then melt-extrusion molding. And
The polymer crushed dust is a low specific gravity polymer crushed dust containing a porous material and having a specific gravity of 0.8 or less, and the inorganic fine powder dust contains iron fine powder or iron oxide fine powder.
A method for producing a secondary material for steel, wherein the low specific gravity polymer crushed dust and the inorganic fine powder dust are applied (mabushi) and mixed, followed by the melt extrusion molding.   The method for producing a secondary material for steel according to claim 1, wherein the specific gravity difference sorting is performed by wind sorting using floating or sinking.   The method for producing a secondary material for steel according to claim 1 or 2, wherein the porous material is a polymer foam and / or a polymer nonwoven fabric.   The low-density polymer coarsely pulverized dust is subjected to the primary specific gravity difference-sorted light-weighted primary sorting, and after the coarse pulverization, the secondary specific gravity difference is further sorted to remove rubber, hard plastic, etc., and the specific gravity is 0.5 or less. The method for producing a secondary material for steel according to claim 1, wherein the method is a next-sorted lightweight material.   5. The secondary material for steel according to claim 4, wherein the low specific gravity polymer crushed dust is obtained by removing the secondary sorted light-weight material and further removing earth and sand, glass fine powder and the like by a roll screen. Method.   The low specific gravity polymer coarsely pulverized dust is obtained by removing the iron pieces with a magnetic separator after crushing the secondary sorted lightweight material from which the earth and sand, glass fine powder, etc. have been removed, to a size equal to 50 mm under. The method for producing a secondary material for steel according to claim 5.   7. An extrusion molded body having a specific gravity of 1.3 to 3.0 is melt-extruded by adjusting a mixing ratio of the low specific gravity polymer coarse dust and the inorganic fine powder dust. The manufacturing method of the auxiliary material for steel of description.   In the coating and mixing, a plurality of rectangular paddles are arranged to protrude radially from the peripheral surfaces of two parallel horizontal rotation shafts along a spiral of a predetermined lead so as to protrude radially. The method for producing a secondary material for steel according to any one of claims 1 to 7, wherein the surface is formed by using a coating and mixing apparatus having a surface along the spiral.   The method for producing a secondary material for steel according to claim 1, wherein the low specific gravity polymer crushed dust is low specific gravity ASR derived from Automobile Shredder Residues (ASR).   The method for producing a secondary material for steel according to claim 1, wherein the inorganic fine dust is derived from iron product processing such as shot peening, shot blasting, and polishing.   Inorganic fine powder dust substantially composed of iron powder and / or iron oxide is combined with a melt of low specific gravity polymer coarse dust having a specific gravity of 0.5 or less, and the specific gravity is adjusted to 1.3 to 3.0. An auxiliary material for steel, characterized by being an extruded product.   The secondary material for steel according to claim 11, wherein the low specific gravity polymer crushed dust is low specific gravity ASR derived from Automobile Shredder Residues (ASR).   The secondary material for steel according to claim 11 or 12, wherein the inorganic fine powder dust is derived from iron product processing such as shot peening, shot blasting, and polishing.

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