JP2011094208A - Method for recovering dust in scrap shredder facility - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To effectively and stably recover a dust which can be used as a raw material for iron manufacture and the like, from a dust which has been collected in steps of crushing and selecting scrap in a scrap shredder facility. <P>SOLUTION: This recovering method includes classifying a dust (A) which has been collected in the scrap shredder facility, with a sieve, preferably with a sieve having a sieve mesh of 1-5 mm, and recovering the sieved dust (a) as an iron-containing dust. The preferable recovering method includes magnetically selecting the dust (a) which has been obtained in the classification treatment to obtain a dust which has a higher content of iron. <P>COPYRIGHT: (C)2011,JPO&INPIT

Description

  In the scrap shredder facility for crushing and sorting scrap and collecting high-quality iron scrap, the present invention enables iron to be used as a raw material for iron making from dust collected in the crushing and sorting process of scrap. The present invention relates to a method for recovering contained dust.

Conventionally, steel scrap such as scrapped automobiles and building waste has been used as a raw material for iron making (iron source). In order to use it as an iron-making material, iron scrap is crushed and sorted in a shredder facility, and only good-quality iron scrap is recovered as an iron-making material (for example, Patent Document 1).
In the process of crushing and sorting iron scrap in a scrap shredder facility, a large amount of dust is generated, and this dust is sorted by wind and collected by a cyclone or the like.

JP 2009-84603 A

Although the dust collected in the scrap shredder facility may reach 7 to 8 mass% of the amount of scrap input to the facility, conventionally, the entire amount of collected dust is treated as industrial waste. However, the industrial waste treatment of dust is very expensive, and it is desired to reduce the cost.
Accordingly, an object of the present invention is to provide a method capable of efficiently and stably recovering dust that can be used as a raw material for steelmaking from dust collected in a scrap crushing / sorting process in a scrap shredder facility. It is to provide.

In order to solve the above-mentioned problems, the present inventors have conducted a detailed study on the components of collected dust and the treatment method. As a result, the collected dust contains a large amount of iron, and by classifying the collected dust under specified conditions, it is possible to collect high-quality iron-containing dust that can be used as a raw material for iron making, etc. I found. Among the dust collected by the scrap shredder equipment, the so-called earth-and-dust dust collected at the outlet side of the shredder has a particularly high iron content. And was found to be particularly suitable as a raw material for iron making.
The present invention has been made on the basis of such findings and has the following gist.

[1] A method for collecting dust in a scrap shredder facility, wherein the dust (A) collected in the scrap shredder facility is classified with a sieve, and the dust (a) under the sieve is collected as iron-containing dust.
[2] A method for collecting dust in a scrap shredder facility, wherein the dust (A) is collected after the dust (A) is separated and removed at the exit side of the shredder in the collection method of [1].
[3] The scrap shredder according to the above [1] or [2], wherein the iron in the dust (a) is mainly composed of at least one selected from iron sand and scale. How to collect dust in equipment.

[4] A method for collecting dust in a scrap shredder facility, wherein the dust (A) is classified by a sieve having a sieve mesh of 1 to 5 mm in the collection method of any one of [1] to [3].
[5] In the collection method according to any one of [1] to [4], the dust is recovered in a scrap shredder facility, wherein the dust (a) is subjected to a magnetic sorting process to obtain a dust having a high iron content. Method.
[6] In the collection method according to any one of [1] to [5] above, in the magnetic sorting process, two or more magnetic sorters having different magnetic attraction forces are selectively used or the magnetic attraction force can be adjusted. A dust collecting method in a scrap shredder facility, wherein dust having different iron content is selectively obtained by using

  According to the present invention, it is possible to efficiently and stably recover dust having a high iron content that can be turned into a steelmaking raw material from dust collected by a scrap shredder facility. Effective use can be achieved, and the cost required for the industrial waste treatment of dust can be reduced.

Explanatory drawing which shows typically one Embodiment of the scrap shredder equipment by which dust is collected by the crushing and sorting process of scrap Explanatory drawing which shows one Embodiment of this invention method Explanatory drawing which shows the embodiment of the magnetic sorter used for the magnetic sorting of dust in the method of the present invention

FIG. 1 schematically shows an embodiment of a scrap shredder facility in which dust is collected in a scrap crushing / sorting process.
Usually, this kind of scrap shredder equipment is equipped with a shredder, one or more stages of wind sorting mechanisms, one or more stages of magnetic sorters, etc. in order from the upstream side of the processing line. In the present embodiment, a shredder 1, an oscillating sorter 2, a two-stage magnetic sorter 3a, 3b are provided in order from the upstream side of the processing line, and a wind power sorting mechanism mainly for collecting dust. 4, 5, and 6 are provided at the exit side position of the shredder 1, the entry position of the swing sorter 2, and between the magnetic sorter 3a and the magnetic sorter 3b, respectively. In order to perform wind sorting, a hood 14a is provided at the exit position of the shredder 1, a hood 14b is provided above the entry position of the swing sorter 2, and an upper position between the magnetic sorter 3a and the magnetic sorter 3b. A hood 14c is provided at each position.
This equipment also includes various conveyors for conveying materials, 7 is a material supply apron conveyor, 8, 10a and 10b are vibration conveyors, and 9a, 9b and 11 are conveyor conveyors (belt conveyors).

The scrap supplied to the scrap shredder facility in FIG. 1 is crushed by a shredder 1 and then separated by a swing sorter 2 from light (such as plastic or non-ferrous metal) and heavy items. Non-ferrous metal is separated and removed, and finally iron (iron scrap) is sorted by drum type magnetic sorters 3a and 3b. In this series of crushing and sorting steps, dust is separated and removed by the wind sorting mechanisms 4, 5, and 6 and collected.
As described above, separation and removal of dust (wind sorting) and collection are performed by (i) the exit position of the shredder 1, (ii) the entry position of the swing sorter 2, and (iii) the magnetic sorter 3a-magnetic sort. The dust is separated and removed and collected in (i) above, and the dust separated and removed and collected on the downstream side (i.e. (ii) and (iii). ), Which are separated and collected in (), have different components and are collected by separate dust collectors. That is, (i) is collected by the cyclone 12 (dust collector), and (ii) and (iii) are collected by the cyclone 13 (dust collector).

  In the present embodiment, the shredder 1 is composed of a hammer type crusher that crushes the scrap by rotating a plurality of hammers 100. In this shredder 1, for example, low-grade iron scraps mixed with non-ferrous components such as copper wires and plastics derived from scrapped automobiles and building waste materials are crushed into appropriately sized lumps (for example, about 50 to 150 mm). To do. Dust is generated by the action of cutting, impact, friction, etc. at that time, and this dust is sucked (collected) by the wind sorting mechanism 4 at the outlet side position of the shredder 1 and separated and removed, and the discharge line 15 And is collected by the cyclone 12 along the way. The shredder 1 may be of other crushing methods.

Scrap is sequentially sent to the swing sorter 2 and the magnetic sorters 3a and 3b through the shredder 1, and further dust is generated in the course of processing. The dust is input to the swing sorter 2 and the magnetic sorter. 3a and the magnetic separator 3b are separated and removed by the wind sorting mechanisms 5 and 6, respectively, discharged to the discharge line 16 along with the wind sorting carrier gas (air), and trapped by the cyclone 13 along the way. Be collected. In addition, the carrier gas is supplied to the wind power sorting mechanisms 5 and 6 through the carrier gas circulation lines 17 and 18.
The carrier gas that has passed through the cyclones 12 and 13 is removed by a wet dust collector 19. Note that a dry dust collector may be provided in place of the wet dust collector 19.

  The present invention treats the dust collected by the scrap shredder equipment as described above, and separates and collects high-quality iron-containing dust from this. Basically, it is limited to the dust to be treated. There is no. Accordingly, in a scrap shredder facility as shown in FIG. 1, (i) dust separated and removed and collected at the outlet side position of the shredder 1, and (ii) separated and removed and collected at the inlet side position of the swing sorter 2. Any of the collected dust and (iii) dust separated and removed and collected at a position between the magnetic sorter 3a and the magnetic sorter 3b may be used. On the other hand, as a result of investigations and examinations by the present inventors, the dusts (ii) and (iii) have a relatively large amount of non-ferrous components, whereas the dust (i) has a high iron content. found. Here, about 80 mass% of the dust collected by the scrap shredder equipment is the dust of (i) above. Therefore, it is effective to use resources and reduce waste disposal costs to treat this dust. It can be said that it is particularly preferable in terms of chemical conversion. Therefore, in the present invention, it is preferable to treat at least the dust (i) described above as a processing target.

The dust collection method according to the present invention will be described below.
In the method of the present invention, dust A collected by a scrap shredder facility is classified by a sieve (for example, a vibrating sieve), and the dust a under the sieve is recovered as iron-containing dust that can be used as a material. The mesh size of the sieve used for the classification treatment is preferably 1 to 5 mm (more preferably around 3 mm). When the mesh size is less than 1 mm, the amount of collected dust is as low as about 60% by mass, and the efficiency is low. On the other hand, when the mesh size exceeds 5 mm, the mixing of foreign matters (for example, copper wire) inappropriate to be used as a material increases. By further subjecting the dust a obtained by the classification treatment to magnetic sorting, a high-quality iron-containing dust having a higher iron content can be obtained.
As described above, the dust A to be treated in the present invention is preferably dust separated and collected at the exit side position of the shredder 1, and hereinafter, when such dust is to be treated. Will be described.

FIG. 2 shows an embodiment of the method of the present invention, in which 20 is a vibrating sieve, 21a and 21b are drum-type magnetic sorters, and 35 is a switching damper. The switching damper 35 is used to selectively supply dust to the magnetic sorter to be used when the magnetic sorters 21a and 21b are properly used.
The dust A is classified by the vibrating sieve 20, and the dust a under the sieve is recovered as iron-containing dust that can be used as a material. On the other hand, since the dust on the sieve is mainly composed of non-ferrous components (non-ferrous metals, plastics, etc.), it is usually treated as industrial waste.

  As described above, the mesh size of the vibration sieve 20 is preferably about 1 to 5 mm (more preferably around 3 mm). The dust separated and collected at the outlet side of the shredder 1 of the scrap shredder equipment is classified by such a vibrating sieve 20, so that dust having a high ratio of plastic, rubber, wood pieces, copper wire, etc. is sieved. Dust with a high iron content becomes the upper sieve. The dust on the sieve hinders the recycling of the dust (for example, agglomerates the dust into a steelmaking raw material), and in the present invention, such dust is simply removed by performing the classification process as described above. It has been found that dust that has been removed and has a high iron content can be selected and recovered. It was also found that the iron content in the sorted and collected iron-containing dust was mainly iron sand and scale.

  The dust a (under-sieving dust) selected and collected by the classification process usually has an iron content of about 35 to 40 mass% and can be used as it is as a raw material for iron making. In this embodiment, the dust a Magnetic sorting is performed to obtain dust with a higher iron content and stabilized components. There is no particular restriction on the method of magnetically sorting the dust a, but from the viewpoint of processing efficiency and sorting accuracy, a magnetic sorting process using a drum type magnetic sorter as used in this embodiment is preferable.

  Moreover, in this embodiment, the iron containing dust from which iron content rate differs, ie, high purity Fe dust (for example, iron content rate is 60 to 60--) by using properly two magnetic sorters 21a and 21b having different magnetic attraction forces. 70 mass% dust) and low-purity Fe dust (for example, dust having an iron content of about 45 to 55 mass%) are selectively obtained. In the present embodiment, the magnetic sorting machine 21a is constituted by a permanent magnet type drum type magnetic sorting machine, and the magnetic sorting machine 21b is constituted by an AC electromagnet + permanent magnet combined type drum type magnetic sorting machine. The magnetic attraction force of the machine is magnetic sorter 21a <magnetic sorter 21b.

  FIGS. 3 (a) and 3 (b) schematically show the structures of these magnetic sorters 21a and 21b. FIG. 3 (b) shows a magnetic sorter 21a which is a permanent magnet drum magnetic sorter. Is shown. The magnetic sorter 21a is a drum 22 that is driven to rotate, and a permanent magnet that is fixedly arranged inside the drum 22 independently of the drum, and has a semicircular portion from the drum upper end position to the lower end position. A permanent magnet 23 disposed on the inner side, a vibration feeder 24 as supply means for supplying dust a to the upper end position of the drum 22, a supply hopper 27 for supplying dust a to the vibration feeder 24, and the whole drum. A cover 25 having dust discharge ports 250x and 250y is provided below the drum. Of the dust discharge ports 250x and 250y, the dust discharge port 250x located below the drum half circumference where the permanent magnets 23 are arranged inside is a discharge port for non-magnetized dust (dust to be separated and removed). The dust discharge port 250y located below the drum half circumference where no permanent magnet is arranged on the inside is a discharge port for magnetized dust (iron-containing dust to be sorted). A branch plate 26 is provided between the dust outlets 250x and 250y. The branch plate 26 can be tilted in the direction of the dust outlets and the tilt angle can be adjusted. By adjusting the tilt angle of the branch plate 26, the recovery rate and purity of the magnetized dust can be adjusted.

  In the magnetic sorter 21a, the drum 22 is rotationally driven in the direction of the arrow in the figure, and dust a is supplied from the vibration feeder 24 to the top of the rotating drum 22. Of the supplied dust a, non-magnetizable dust falls directly to the dust discharge port 250x without being magnetized on the drum surface. On the other hand, the magnetized dust having a high iron content is magnetized on the drum surface by the action of the permanent magnet 23 inside the drum, and the magnetized state is released after the lower end position of the drum. To do.

  FIG. 3B shows a magnetic sorting machine 21b which is a drum type magnetic sorting machine using an alternating current electromagnet + permanent magnet. The magnetic sorter 21b is a drum 28 that is driven to rotate, a magnet group m that is fixedly arranged inside the drum 28 independently of the drum, and a supply that supplies dust a to the side position of the drum 28. A vibration feeder 31 as a means, a supply hopper 34 for supplying dust a to the vibration feeder 31, and a cover 32 that covers the entire drum and has dust discharge ports 320x and 320y below the drum.

  The magnet group m arranged on the inner side of the drum is arranged on the inner side of the lower half of the drum starting from the drum side position (or the vicinity thereof) to which the dust a is supplied by the vibration feeder 31. The magnet group m is composed of a permanent magnet 29 and an AC electromagnet 30 arranged at intervals along the drum peripheral surface. In the present embodiment, the plurality of permanent magnets 29 and the AC electromagnet 30 are arranged in the drum circumferential direction. Alternatingly arranged. In addition, each AC electromagnet 30 has alternately arranged different magnetic poles in the drum axis direction (for example, N pole-S pole-N pole).

  Of the dust discharge ports 320x and 320y, the dust discharge port 320x located below the dust supply unit side by the vibration feeder 31 is a discharge port for non-magnetized dust (dust to be separated and removed). The dust discharge port 320y located on the lower side opposite to the supply unit side is a discharge port for magnetized dust (iron-containing dust to be sorted). A branch plate 33 is provided between the dust discharge ports 320x and 320y. The branch plate 33 can be tilted in the direction of the dust discharge ports and the tilt angle can be adjusted. By adjusting the tilt angle of the branch plate 33, the recovery rate and purity of the magnetized dust can be adjusted.

In this magnetic sorter 21b, the drum 28 is rotationally driven in the direction of the arrow in the figure, and dust a is supplied from the vibration feeder 31 to the side position of the rotating drum 28. Of the supplied dust a, the non-magnetizable dust having a low iron content falls directly to the dust discharge port 320x without being magnetized on the drum surface. On the other hand, magnetized dust having a high iron content is magnetized on the drum surface by the action of the magnets inside the drum (permanent magnet 29 and AC electromagnet 30), and the magnetized state is released after the lower end of the drum. , And falls to the dust discharge port 320y. At this time, each AC electromagnet 30 is alternately switched between the N pole and the S pole in the drum axis direction, and a kind of vibration action is exerted on the magnetized dust, so that the dust having relatively low magnetizability is screened out. Thus, before reaching the dust outlet 320y, it falls to the dust outlet 320x, and only the highly magnetically adhering dust (dust having a particularly high iron content) remains in the magnetically attached state, passing through the area of the magnet group m. When the wearing state is released, it falls to the dust discharge port 320y. As a result, it is possible to sort out dust having a higher iron content compared to the magnetic sorter 21a which is a permanent magnet type drum type magnetic sorter.
In this embodiment, two magnetic sorters 21a and 21b having different magnetic attractive forces are used, but three or more magnetic sorters having different magnetic attractive forces may be used. Moreover, you may make it selectively obtain the iron containing dust from which an iron content rate differs by using the magnetic sorter which can adjust magnetic attraction force.

  The test of the present invention is carried out using the equipment as shown in FIG. 2, the composition of the dust a recovered by classification with the vibrating sieve 20, the dust recovery by the magnetic selection in the magnetic separator 21a and the magnetic separator 21b. The composition of the magnetically sorted dust was investigated. The results are shown in Table 1. Here, the dust A to be treated is dust that has been separated and removed and collected at the outlet side position of the shredder 1 of the scrap shredder equipment, and is classified by the vibrating sieve 20 (sieving mesh: 3 mm) according to the method of the present invention. It processed and obtained the dust a under the sieve. Furthermore, this dust a was magnetically sorted using a magnetic sorter 21a and a magnetic sorter 21b shown in FIGS. 3 (a) and 3 (b), and dusts having different iron contents were selected.

As shown in Table 1, by classifying dust A according to the method of the present invention, dust a having an increased iron content is obtained as dust under sieve. Further, by further magnetically sorting this dust a, dust having a higher iron content is obtained.

  Further, as described above, by using two or more magnetic sorters 21a and 21b having different magnetic attraction forces, or by using a magnetic sorter capable of adjusting the magnetic attraction force, the iron content is different. The reason why dust is selectively obtained is as follows. For example, taking the dust composition shown in Table 1 as an example, the iron-containing dust selected by the magnetic separator 21a has a high dust recovery rate, but the iron content is 45 mass%, and the Cu content is before the magnetic selection. It is almost the same as the dust a. In contrast, the iron-containing dust selected by the magnetic sorter 21b has a low dust recovery rate, but the iron content is 70 mass%, and the Cu content is halved compared to the dust a before the magnetic selection. Yes. The purpose of magnetically sorting the dust is to reduce the Cu content in addition to increasing the iron content of the dust. For example, when the dust is agglomerated into an iron-making raw material, there are various circumstances. Therefore, it is better to increase the dust recovery rate than to increase the iron content rate of the dust or reduce the Cu content rate, and conversely, rather than increasing the dust recovery rate, the iron content of the dust In some cases, it is better to increase the rate or reduce the Cu content, and a suitable dust can be selectively obtained in each case.

Next, an example of the effect of reducing the industrial waste disposal cost of dust according to the method of the present invention is as follows. In a scrap shredder facility as shown in FIG. 1, for example, when scrap of about 100,000 t / year is processed, the amount of dust separated and collected at the outlet side of the shredder 1 is about 6400 t / year, When this is classified by the method of the present invention, iron-containing dust (iron content: about 35 mass%) of about 6100 t / year is obtained. If this is used as a raw material for iron making as it is, 95% of the industrial waste disposal cost of dust, which has been conventionally required, can be saved. Further, when the obtained iron-containing dust is further magnetically sorted by the magnetic sorter 21a, about 4600t / year of iron-containing dust (iron content: about 45 mass%) is obtained, and when the magnetic sorter 21b is magnetically sorted, it is about 1800t. / Year of iron-containing dust (iron content: about 70 mass%) is obtained respectively. Therefore, in the former case, it is possible to reduce 72% of the industrial waste processing cost of dust, which was conventionally required, and in the latter case, 28% of the dust industrial waste processing cost which was conventionally required. % Can be saved.
The iron-containing dust recovered by the method of the present invention is usually agglomerated and used as an iron-making raw material (iron source) in a shaft furnace or the like.

DESCRIPTION OF SYMBOLS 1 Shredder 2 Oscillating sorter 3a, 3b Magnetic sorter 4, 5, 6 Wind sorting mechanism 7 Material supply apron conveyor 8 Oscillating conveyor 9a, 9b Conveyor 10a, 10b Oscillating conveyor 11 Conveyor 12, 13 Cyclone 14a, 14b, 14c Hood 15, 16 Discharge line 17, 18 line 19 Wet dust collector 20 Vibrating sieve 21a, 21b Magnetic sorter 22 Drum 23 Permanent magnet 24 Vibrating feeder 25 Cover 26 Branch plate 27 Supply hopper 28 Drum 29 Permanent magnet 30 AC electromagnet 31 Vibrating feeder 32 Cover 33 Branch plate 34 Supply hopper 35 Switching damper 250x, 250y Dust outlet 320x, 320y Dust outlet m Magnet group A, a Dust

Claims (6)

  A method for collecting dust in a scrap shredder facility, characterized in that dust (A) collected in a scrap shredder facility is classified with a sieve and dust (a) under the sieve is collected as iron-containing dust.   The method for recovering dust in a scrap shredder facility according to claim 1, wherein the dust (A) is dust collected after being separated and removed at the outlet side position of the shredder.   The method for recovering dust in a scrap shredder facility according to claim 1 or 2, wherein the iron in the dust (a) is mainly composed of at least one selected from iron sand and scale.   The dust recovery method for scrap shredder equipment according to any one of claims 1 to 3, wherein the dust (A) is classified by a sieve having a sieve mesh of 1 to 5 mm.   The dust recovery method according to any one of claims 1 to 4, wherein the dust (a) is subjected to a magnetic separation process to obtain dust having a high iron content.   In the magnetic sorting process, it is possible to selectively obtain dust with different iron content by using two or more magnetic sorters with different magnetic attraction force or using a magnetic sorter with adjustable magnetic attraction force. The method of recovering dust in the scrap shredder facility according to any one of claims 1 to 5.

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