Scrap sorting apparatus and scrap sorting method using the same

Abstract

To provide a scrap sorting apparatus which uses a single magnetic separator to sort scrap into three types of non-magnetic matters, lightweight magnetic matters, and heavyweight magnetic matters, and a scrap sorting method using the same.SOLUTION: A gap for allowing non-magnetic matters to pass therethrough is provided between a conveyor and a drum-type magnetic separator. When scrap is conveyed by the conveyor toward the drum-type magnetic separator, non-magnetic matters in the scrap are caused to fall through the gap, and lightweight magnetic matters and heavyweight magnetic matters in the scrap are attracted to a rotating drum and conveyed by the drum-type magnetic separator via a maximum height of the rotating drum. Thereafter, the heavyweight magnetic matters are caused to fall from the rotating drum by gravity against a magnetic force of a magnet, and the lightweight magnetic matters are caused to fall from the rotating drum by reaching a region in which attraction by the magnetic force of the magnet is not possible.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a scrap sorting device for sorting non-magnetic materials, light magnetic materials, and heavy magnetic materials from scrap, and a scrap sorting method using the same. [Background technology]

[0002] In recent years, there has been a growing need to reduce CO2 emissions to curb global warming, and in the steel industry, the electric furnace method has been attracting attention as an alternative to the blast furnace method, which emits CO2 gas. The electric furnace method primarily uses scrap iron, which is made from used automobiles, discarded home appliances, buildings, and other used iron products, as its main raw material. However, scrap automobiles, discarded home appliances, buildings, and other used iron products contain various metals and non-metals in addition to iron. For this reason, when shredding scrap generated from waste materials such as used iron products in shredder facilities, it is common to separate it into iron, other metals, and non-metals.

[0003] Patent Document 1 discloses a method of separating non-magnetic materials by using a weak magnetic separator with low sensitivity to separate light magnetic materials from waste, and then using a strong magnetic separator with high sensitivity to remove heavy magnetic materials from the separated waste. Patent Document 2 discloses a drum-type magnetic separator as a method of separating non-magnetic materials and magnetic materials using a single device, in which a ferromagnetic matrix excited by internal and external magnetic poles acts as a magnet, separating the materials into non-magnetic materials, magnetic materials, and intermediate materials. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Japanese Patent Application Laid-Open No. 2006-75793 [Patent Document 2] Japanese Patent Application Publication No. 4-74545 [Patent Document 3] Japanese Patent Application Publication No. 11-347443 Summary of the Invention [Problem to be solved by the invention]

[0005] When scrap is fed into a shredder, if heavy objects such as large iron blocks, such as thick steel plates or steel sections, are fed in, there is a risk that the shredder will be damaged. For this reason, before feeding the scrap into the shredder, it is necessary to separate not only non-magnetic materials such as non-metallic materials from the scrap, but also heavy materials such as iron blocks. However, heavy materials such as iron blocks have relatively few impurities and can be reused as raw materials for steelmaking, so it is desirable to separate them from non-magnetic materials.

[0006] Furthermore, in the process of transporting scrap to shredder equipment, the scrap may be crushed to a certain size using a pre-shredder or the like, and various facilities are required before the scrap is crushed. Therefore, when removing heavy objects or non-magnetic objects such as non-metallic objects from the scrap that may damage the shredder equipment, it is required to do so on a small scale as much as possible due to facility constraints.

[0007] The method described in Patent Document 1 requires two magnetic separators, a strong magnetic separator and a weak magnetic separator, which makes the device complex, the equipment large-scale, and the cost high.The method described in Patent Document 2 is a method intended to remove magnetic materials from powder, and is not intended to separate light and heavy magnetic materials.

[0008] In view of the above-mentioned problems, the present invention aims to provide a scrap sorting device that can sort scrap into three types of materials, namely, non-magnetic materials, light magnetic materials, and heavy magnetic materials, using a single magnetic separator, and a scrap sorting method using the same. [Means for solving the problem]

[0009] The scrap sorting device of the present invention is a scrap sorting device that sorts out non-magnetic objects, light magnetic objects having a weight less than a reference weight, and heavy magnetic objects having a weight equal to or greater than the reference weight from scrap, and includes a conveyor that transports the scrap, and a drum-type magnetic separator that uses magnets fixed inside to attract the light magnetic objects and heavy magnetic objects in the scrap transported on the conveyor to a rotating drum, and a gap is provided between the conveyor and the drum-type magnetic separator to allow the non-magnetic objects to pass through.When the scrap is transported on the conveyor toward the drum-type magnetic separator, the non-magnetic objects in the scrap fall into the gap, and the light magnetic objects and heavy magnetic objects in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, and then the heavy magnetic objects fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic objects fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet.

[0010] The scrap sorting method of the present invention is a scrap sorting method using a scrap sorting device having a conveyor that transports scrap and a drum-type magnetic separator that uses magnets fixed inside to attract light magnetic objects and heavy magnetic objects in the scrap transported on the conveyor to a rotating drum, and is characterized in that a gap is provided between the conveyor and the drum-type magnetic separator to allow non-magnetic objects in the scrap to pass through, and when the scrap is transported on the conveyor toward the drum-type magnetic separator, the non-magnetic objects in the scrap fall into the gap, and the light magnetic objects and heavy magnetic objects in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, and then the heavy magnetic objects are allowed to fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic objects fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet. [Effects of the Invention]

[0011] According to the present invention, one magnetic separator can separate scrap into three types: non-magnetic materials, light magnetic materials, and heavy magnetic materials. [Brief explanation of the drawings]

[0012] [Figure 1] FIG. 1 is a diagram for explaining an outline of a pickup-type drum-type magnetic separator according to a first embodiment of the present invention. [Figure 2] 3A and 3B are diagrams illustrating how a light magnetic object and a heavy magnetic object are picked up in the first embodiment of the present invention. [Figure 3] FIG. 2 is a diagram illustrating how a heavy magnetic object is dropped in the first embodiment of the present invention. [Figure 4] FIG. 10 is a diagram for explaining an overview of an overfeed type drum magnetic separator according to a second embodiment of the present invention. [Figure 5] 10 is a diagram illustrating how non-magnetic objects, light magnetic objects, and heavy magnetic objects fall from a conveyor in the second embodiment of the present invention. FIG. [Figure 6] 10A and 10B are diagrams illustrating a method for separating light magnetic objects and heavy magnetic objects in another embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0013] The following embodiments of the present invention will be described with reference to the drawings. In the following description, a lightweight magnetic material is a magnetic material that has a shape (e.g., a lump or a wire) different from powder that is less than a reference weight and can be shredded in a shredder, and a heavy magnetic material is a magnetic material that is equal to or greater than a reference weight and has the potential to damage the shredder. Examples of heavy magnetic materials include large iron blocks such as thick steel plates and structural steel. The reference weight value can be changed as appropriate depending on the durability of the shredder equipment used.

[0014] (First embodiment) 1 is a diagram for explaining an overview of a scrap sorting device 1 using a pickup-type drum-type magnetic separator 10 according to this embodiment. Details of the scrap sorting device 1 according to this embodiment will be described below with reference to FIG.

[0015] As shown in FIG. 1, the scrap sorting device 1 comprises a drum-type magnetic separator 10, a conveyor 30, a first partition plate 31, and a second partition plate 32. The drum-type magnetic separator 10 is configured so that a rotating drum 13 equipped with an electromagnet 12 rotates around a drum shaft 11 in the direction of the solid arrow A1. In other words, the rotating drum 13 rotates so that it moves upward when viewed from the conveyor 30 side. Meanwhile, the electromagnet 12 is fixed inside the rotating drum 13 so that it does not rotate while the rotating drum 13 rotates. The magnetic force can be changed by adjusting the current flowing through the electromagnet 12. Note that a permanent magnet may be used as the magnet to fix the magnetic force of the drum-type magnetic separator 10.

[0016] The conveyor 30 conveys scrap that has been shredded, for example, by a pre-shredder in a previous process. The scrap mainly includes solid non-magnetic materials 21, such as non-ferrous metals, plastics, rubber, and dust, which cannot be attracted by the magnetic force of the electromagnets 12; lightweight magnetic materials 22, such as iron pieces; and heavy magnetic materials 23, such as thick steel plates and sections of steel beams. As the scrap is transported from the conveyor 30, the non-magnetic materials 21 in the scrap fall through the gap between the conveyor 30 and the rotating drum 13. Meanwhile, the lightweight magnetic materials 22 and heavy magnetic materials 23 in the scrap are attracted to the rotating drum 13 by the electromagnets 12 and transported to the maximum height of the rotating drum 13 while being attracted to the rotating drum 13.

[0017] Additionally, a first partition plate 31 and a second partition plate 32 are installed below the drum-type magnetic separator 10. The first partition plate 31 is a partition for forming zone Z1, and as shown by the dotted arrow A2, allows non-magnetic materials 21 to fall from the conveyor 30 into zone Z1. For this reason, the first partition plate 31 is installed close to the rotating drum 13 to prevent the non-magnetic materials 21 from falling into the adjacent zone Z3.

[0018] On the other hand, the second partition plate 32 is a partition for forming zone Z2, into which heavy magnetic objects 23 fall in the direction indicated by dotted arrow A3, and is installed to form a gap between it and the rotating drum 13 so that lightweight magnetic objects 22 can pass over the rotating drum 13. The size of the gap between it and the rotating drum 13 is determined according to the size of the lightweight magnetic objects 22 being transported on the conveyor 30. The first partition plate 31 and the second partition plate 32 also form zone Z3, into which lightweight magnetic objects 22 fall in the direction indicated by dotted arrow A4, between zone Z1 and zone Z2. The size of the rotating drum 13 and the size of the scrap are both roughly the same, on the order of 1 meter, and the objects to be sorted are large compared to the size of the rotating drum 13. Therefore, zones Z1 to Z3 are provided to allow for accurate sorting of non-magnetic objects 21, lightweight magnetic objects 22, and heavy magnetic objects 23.

[0019] The non-magnetic objects 21, light magnetic objects 22, and heavy magnetic objects 23 dropped into zones Z1 to Z3 are collected in collection boxes or the like and reused. The light magnetic objects 22 may contain a large amount of metals other than iron, and the collected light magnetic objects 22 are transported to a factory equipped with shredding equipment, where they are further crushed and separated into iron and non-ferrous metals. The light magnetic objects 22 may also be dropped onto another conveyor connected to the shredding equipment via zone Z3. On the other hand, the collected heavy magnetic objects 23 are large iron blocks that contain relatively few components other than iron, and are therefore reused directly in equipment such as an electric furnace.

[0020] Next, a method for separating scrap into non-magnetic, light-weight, and heavy-weight magnetic objects will be described in detail. First, the method for separating magnetic and non-magnetic objects will be described with reference to FIG. 2. FIG. 2 is a diagram illustrating the process of picking up light-weight magnetic objects 22 and heavy-weight magnetic objects 23. When scrap is transported horizontally on a conveyor 30, non-magnetic objects 21 in the scrap fall directly into the gap between the conveyor 30 and the rotating drum 13. Meanwhile, the light-weight magnetic objects 22 and heavy-weight magnetic objects 23 are attracted to the rotating drum 13 by the magnetic force of the electromagnet 12 before falling from the conveyor 30. At this time, a magnetic force is required that is strong enough to attract the heavy-weight magnetic objects 23 to the rotating drum 13 while preventing the heavy-weight magnetic objects 23 from falling off the rotating drum 13 due to gravity.

[0021] The size of the gap between the conveyor 30 and the rotating drum 13 can be changed by adjusting the position of the conveyor 30 depending on the size of the non-magnetic objects 21. Increasing the gap between the conveyor 30 and the rotating drum 13 allows even relatively large non-magnetic objects 21 to fall from the conveyor 30. On the other hand, if the gap is too large, the magnetic force will not reach the end of the conveyor 30 sufficiently, and some of the light magnetic objects 22 and heavy magnetic objects 23 may fall from the conveyor 30 and become mixed in with the non-magnetic objects 21. If the gap between the conveyor 30 and the rotating drum 13 is too small, relatively large non-magnetic objects 21 may not fall from the conveyor 30 and may get caught between the conveyor 30 and the rotating drum 13. Therefore, the size of the gap between the conveyor 30 and the rotating drum 13 is determined depending on the type of scrap (particularly the type and size of the non-magnetic objects 21 and the weight of the heavy magnetic objects 23), and the magnetic force of the electromagnet 12 is determined depending on the size of the gap.

[0022] The height of the conveyor 30 relative to the drum-type magnetic separator 10 is not particularly limited. However, in the drum-type magnetic separator 10 according to this embodiment, the height is set to a value sufficient to attract the light magnetic materials 22 and the heavy magnetic materials 23 to the rotating drum 13 and sufficiently separate the non-magnetic materials 21. For example, if the conveyor 30 is too low, the area of ​​the electromagnet 12 must be enlarged along the circumferential direction, and the zone Z1 shown in FIG. 1 becomes narrower. However, if the conveyor 30 can generate a magnetic force sufficient to attract the heavy magnetic materials 23, the heavy magnetic materials 23 can be attracted to the rotating drum without passing directly above the gap, thereby ensuring that the heavy magnetic materials 23 are attracted to the rotating drum. In contrast, if the conveyor 30 is positioned near the side of the drum-type magnetic separator 10, the heavy magnetic materials 23 must be attracted to the rotating drum 13 by passing directly above the gap, without being affected by gravity. However, the area of ​​the electromagnet 12 can be reduced along the circumferential direction, and the zone Z1 can be sufficiently secured.

[0023] Next, a method for separating lightweight magnetic objects from heavy magnetic objects will be described with reference to FIG. 3. FIG. 3 is a diagram illustrating how heavy magnetic objects are dropped. In this embodiment, the dropping position changes depending on the balance between magnetic force and gravity, and the objects are separated into lightweight magnetic objects 22 and heavy magnetic objects 23. The lightweight magnetic objects 22 move while being attracted to the rotating drum 13 by the electromagnet 12, and remain attracted in areas where the magnetic force of the electromagnet 12 is maintained. When the lightweight magnetic objects 22 reach an area inside where no electromagnet 12 is installed due to the rotation of the rotating drum 13, the magnetic force gradually weakens as the lightweight magnetic objects 22 move away from the electromagnet 12. At a point where the magnetic force is insufficient to attract the lightweight magnetic objects against gravity, the lightweight magnetic objects 22 drop and are separated from the drum-type magnetic separator 10.

[0024] On the other hand, the drop position of the heavy magnetic object 23 is determined by the relationship between the magnetic force in the direction of solid arrow A31, gravity in the direction of solid arrow A32, and centrifugal force in the direction of solid arrow A33. Because the gravity and centrifugal force of the heavy magnetic object 23 are greater than those of the light magnetic object 22, the heavy magnetic object 23 will drop from the rotating drum 13 when these components become greater than the magnetic force. The range of the drop position is determined by the time the heavy magnetic object 23 is transported on the rotating drum 13 and reaches the same height as the drum axis 11 of the rotating drum 13 until it reaches the lowest point on the rotating drum 13. The drop position of the heavy magnetic object 23 can be adjusted by the magnetic force of the electromagnet 12 or the rotational speed of the rotating drum 13. Reducing the magnetic force of the electromagnet 12 or increasing the rotational speed of the rotating drum 13 will cause the heavy magnetic object 23 to drop more quickly. At this time, the magnetic force of electromagnet 12 and the rotation speed of rotating drum 13 are adjusted so that even the lightest heavy magnetic objects to be sorted as heavy magnetic objects fall into zone Z2. Furthermore, since increasing the rotation speed of rotating drum 13 also increases the overall amount of scrap processed, when the rotation speed of rotating drum 13 is increased, it is preferable to also increase the speed of conveyor 30.

[0025] The boundary between lightweight and heavy magnetic objects varies depending on the shredding equipment's processing capacity, the type of magnetic material, and the combination of magnetic materials. When transporting lightweight magnetic materials to shredding equipment with durable equipment and a relatively wide processing capacity, the upper weight limit for the lightweight magnetic materials can be increased. The boundary between lightweight and heavy magnetic objects can be adjusted by changing the magnetic force of electromagnet 12 or the rotational speed of rotating drum 13. For example, increasing the magnetic force of electromagnet 12 makes it more difficult for the lightweight magnetic materials to fall due to gravity against the magnetic force, thereby increasing the upper weight limit. Furthermore, decreasing the rotational speed of rotating drum 13 reduces the centrifugal force, thereby weakening the force that separates the lightweight magnetic materials from rotating drum 13, thereby increasing the upper weight limit. Furthermore, if the position of second partition plate 32, which separates zones Z2 and Z3, can be adjusted, the upper weight limit for the lightweight magnetic materials can be increased by, for example, widening zone Z3.

[0026] As described above, in the pickup-type drum-type magnetic separator 10 of this embodiment, the light-weight magnetic objects 22 and the heavy-weight magnetic objects 23 are attracted to the rotating drum 13 before falling from the conveyor 30, while the non-magnetic objects 21 fall in the direction opposite to the rotation of the rotating drum 13. The light-weight magnetic objects 22 and the heavy-weight magnetic objects 23 are then transported around the drum shaft 11 toward the opposite side of the conveyor 30 while still attracted to the rotating drum 13. The heavy-weight magnetic objects 23 then fall due to gravity, resisting the magnetic force, midway through the range of the magnetic force of the electromagnet 12. Only the light-weight magnetic objects 22 are transported on the rotating drum 13, and then fall when they move away from the electromagnet 12 and can no longer be attracted by the magnetic force. In this way, in this embodiment, a single magnetic separator can separate scrap into three types: non-magnetic objects, light-weight magnetic objects, and heavy-weight magnetic objects.

[0027] 1, in the pickup-type drum-type magnetic separator 10, the electromagnet 12 must be provided over a range in the circumferential direction from a position where the light magnetic materials 22 and the heavy magnetic materials 23 are attracted to the rotating drum 13 to a position where the heavy magnetic materials 23 fall from the rotating drum 13 and only the light magnetic materials 22 can be attracted to the rotating drum 13 (for example, a position beyond the second partition plate 32). Therefore, the range in which the electromagnet 12 exists along the circumferential direction is set to more than 180°, and preferably 270° or more.

[0028] Furthermore, when attracting the heavy magnetic object 23 to the rotating drum 13, a stronger magnetic force is preferable. However, when dropping the heavy magnetic object 23, a weaker magnetic force allows the heavy magnetic object 23 to drop faster. Therefore, the magnetic force may be different when attracting the heavy magnetic object 23 and when dropping it. For example, as shown in FIG. 1, three types of electromagnets, 12a to 12c, may be provided, and the magnetic force may be set to be weaker in the order of 12a, 12b, and 12c. Furthermore, the number of types of electromagnets may be two, or four or more. This allows the magnetic force to be strongest when attracting the heavy magnetic object 23 to the rotating drum 13 and weakest at the point where the heavy magnetic object 23 drops.

[0029] As a method for providing a gradient in the magnetic force from the electromagnet, for example, a plurality of strip-shaped magnets may be provided inside the rotating drum, and the magnetic flux density on the surface of the rotating drum may be gradually reduced from the upstream side to the downstream side, as in the method described in Patent Document 3. As described above, the specific shape of the electromagnet 12 is not particularly limited as long as the light magnetic objects 22 and heavy magnetic objects 23 can be attracted by magnetic force from the conveyor 30 and attached to the rotating drum 13, and only the light magnetic objects 22 can be dropped into zone Z3.

[0030] The conveyor 30 that transports the scrap may be a normal conveyor, or it may be a vibrating conveyor that uses vibrations to flatten piled scrap. However, if the scrap is transported in a partially piled state, the light magnetic objects 22 or the heavy magnetic objects 23 may be attracted to the rotating drum 13 in an irregular manner. For example, if the light magnetic objects 22 are attracted to the rotating drum 13 so as to get caught on the heavy magnetic objects 23, or if the light magnetic objects 22 are attracted to the heavy magnetic objects 23 without being directly attracted to the rotating drum 13, the light magnetic objects 22 may fall at the same time as the heavy magnetic objects 23 fall.

[0031] Furthermore, there are cases where the relatively heavy lightweight magnetic objects 22 are attracted to the rotating drum 13 in an unstable state (for example, when attracted by a surface with a small area). In this case, the magnetic attraction force is weaker, and the lightweight magnetic objects 22 may fall at the point where the heavy magnetic objects 23 would normally fall. From the above perspective, a vibrating conveyor such as a vibrating feeder is preferable for the conveyor 30 that transports the scrap, but in an environment where the scrap is transported in a flat state rather than in a pile, a normal conveyor may also be used.

[0032] In the drum-type magnetic separator 10 according to this embodiment, as described above, the first partition plate 31 is installed close to the rotating drum 13. However, if the first partition plate 31 is far away from the gap between the conveyor 30 and the rotating drum 13, the non-magnetic materials 21 will not fall into zone Z3, and therefore the first partition plate 31 does not have to be installed close to the rotating drum 13. In the example shown in FIG. 1, the first partition plate 31 is installed obliquely with respect to the direction of gravity and functions as a chute that drops the non-magnetic materials 21, but the first partition plate 31 may also be installed vertically (in the direction of gravity).

[0033] On the other hand, as described above, the second partition plate 32 is used to separate the light magnetic objects 22 from the heavy magnetic objects 23, but because the heavy magnetic objects 23 fall using gravity, they do not remain attracted to the rotating drum 13 and do not exceed the lowest position of the rotating drum 13. Therefore, the second partition plate 32 is installed assuming that the heavy magnetic objects 23 will fall from the rotating drum 13 between when they are transported on the rotating drum 13 and reach the same height as the drum shaft 11 of the rotating drum 13, and when they reach the lowest position of the rotating drum 13. Furthermore, if the heavy magnetic objects 23 fall and collide with the second partition plate 32, this may damage the second partition plate 32. Therefore, it is preferable that the second partition plate 32 be made of a shape and material that will not cause damage, or that the second partition plate 32 be installed so that it will not collide with the heavy magnetic objects 23 even if they fall.

[0034] Furthermore, as mentioned above, scrap is larger than powder relative to the size of the rotating drum 13, so the three zones Z1 to Z3 must each be provided over a wide area to ensure separation accuracy. For example, the method described in Patent Document 2 can separate the powder material into three types: non-magnetic, magnetic, and intermediate. However, because all three types are transported in the same direction without passing through the maximum height of the rotating drum, the zones into which the three types fall are very narrow and close to each other. Therefore, when attempting to apply the method described in Patent Document 2 to large materials such as scrap, the separation points of the three zones (labeled A, B, and C) are too close to each other, and non-magnetic, light magnetic, and heavy magnetic materials are all transported in the same direction, resulting in problems with separation accuracy. For example, the area where Zone B should fall is too narrow compared to the size of the scrap, resulting in problems such as materials that should fall into Zone B falling into Zone A or Zone C and becoming mixed in. In contrast, according to this embodiment, the non-magnetic materials 21 are dropped so as to pass through the gap between the conveyor 30 and the drum-type magnetic separator 10, and the light magnetic materials 22 and heavy magnetic materials 23 are transported via the maximum height of the rotating drum 13. With this configuration, three zones (Z1, Z2, Z3) can be set over a wide range around the periphery of the rotating drum, which is 360° in circumference, and this enables highly accurate sorting even for scrap with a similar size order compared to the rotating drum.

[0035] (Second embodiment) 4 is a diagram for explaining an overview of a scrap sorting device 4 using an overfeed type drum-type magnetic separator 40 according to this embodiment. Hereinafter, details of the scrap sorting device 4 according to this embodiment will be described with reference to FIG.

[0036] As shown in FIG. 4, the scrap sorting device 4 is composed of a drum-type magnetic separator 40, a conveyor 30, a first partition plate 31, and a second partition plate 32. The drum-type magnetic separator 40 is configured so that a rotating drum 13 equipped with an electromagnet 12 rotates around a drum shaft 11 in the direction of the solid arrow A1. In other words, the rotating drum 13 rotates in the same direction as the conveyor 30 when viewed from the conveyor 30 side. Meanwhile, the electromagnet 12 is fixed inside the rotating drum 13 so that it does not rotate when the rotating drum 13 rotates. The magnetic force can be changed by adjusting the current flowing through the electromagnet 12. To fix the magnetic force of the drum-type magnetic separator 40, a permanent magnet may be used as the magnet, as in the first embodiment.

[0037] Conveyor 30 carries scrap that has been shredded, for example, by a pre-shredder in a previous process. As the scrap is transported horizontally on conveyor 30, non-magnetic objects 21 in the scrap fall through the gap between conveyor 30 and rotating drum 13, flow in the opposite direction to the rotation of rotating drum 13, and fall onto first partition plate 31. Meanwhile, light magnetic objects 22 and heavy magnetic objects 23 in the scrap also fall through the gap between conveyor 30 and rotating drum 13, but are attracted to rotating drum 13 by electromagnets 12 and are transported via the maximum height of rotating drum 13.

[0038] Similarly to the first embodiment, a first partition plate 31 and a second partition plate 32 are installed below the drum-type magnetic separator 10, forming a zone Z1 where non-magnetic objects 21 fall in the direction indicated by dotted arrow A42, a zone Z2 where heavy magnetic objects 23 fall in the direction indicated by dotted arrow A43, and a zone Z3 where light magnetic objects 22 fall in the direction indicated by dotted arrow A44. Similarly to the first embodiment, the first partition plate 31 is installed close to the rotating drum 13, and the second partition plate 32 is installed so as to form a gap between it and the rotating drum 13. Thus, in this embodiment, the three zones Z1 to Z3 can each be provided over a wider area than in the first embodiment.

[0039] Next, a method for separating scrap into non-magnetic materials, light magnetic materials, and heavy magnetic materials will be described in detail. Note that the method for separating light magnetic materials and heavy magnetic materials is the same as in the first embodiment, so a description thereof will be omitted. Hereinafter, the method for separating magnetic materials and non-magnetic materials will be described with reference to FIG. 5.

[0040] FIG. 5 is a diagram illustrating how non-magnetic objects 21, lightweight magnetic objects 22, and heavy magnetic objects 23 fall from conveyor 30. As shown in FIG. 5, when scrap is transported on conveyor 30, non-magnetic objects 21, lightweight magnetic objects 22, and heavy magnetic objects 23 in the scrap all fall from conveyor 30 and collide with the surface of rotating drum 13. At this time, lightweight magnetic objects 22 and heavy magnetic objects 23 are attracted to rotating drum 13 by the magnetic force of electromagnet 12 and are transported on rotating drum 13. In contrast, non-magnetic object 21 is not attracted to rotating drum 13 and is not transported on rotating drum 13, but flows in the opposite direction to the rotation of rotating drum 13 and falls. Because lightweight magnetic objects 22 and heavy magnetic objects 23 fall from conveyor 30 due to gravity and are attracted to rotating drum 13, the magnetic force from electromagnet 12 when they fall from conveyor 30 can be smaller than in the first embodiment. Furthermore, the installation range of electromagnet 12 along the circumferential direction can be made shorter than in the first embodiment.

[0041] Furthermore, the gap between the conveyor 30 and the rotating drum 13 must be large enough to allow at least the non-magnetic objects 21 to pass through. The size of the gap can be adjusted by adjusting the position of the conveyor 30 depending on the type of scrap. Increasing the gap between the conveyor 30 and the rotating drum 13 allows even relatively large non-magnetic objects 21 to fall from the conveyor 30. However, increasing the gap increases the vertical distance from the end of the conveyor 30 to the rotating drum 13, increasing the impact of the drop onto the rotating drum 13. If the impact is too great, the surface of the rotating drum 13 may be damaged when the heavy magnetic objects 23 fall, or some of the light magnetic objects 22 and heavy magnetic objects 23 may fall into zone Z1. Therefore, the gap between the conveyor 30 and the rotating drum 13 should not be larger than necessary and should be determined depending on the type of scrap (particularly the type and size of the non-magnetic objects 21).

[0042] Meanwhile, the height of the conveyor 30 relative to the drum-type magnetic separator 40 is not particularly limited, but in the case of the drum-type magnetic separator 40 according to this embodiment, it must be set taking into account that the light magnetic objects 22 and heavy magnetic objects 23 also fall from the conveyor 30. For example, if the conveyor 30 is too low, the point at which the scrap on the rotating drum 13 falls will also be low, and the electromagnets 12 will need to be spread out in the circumferential direction. Furthermore, since the gradient of the rotating drum surface relative to the horizontal direction becomes large at the fall point, it is necessary to increase the magnetic force so that the light magnetic objects 22 and heavy magnetic objects 23 do not fall together with the non-magnetic objects 21.

[0043] On the other hand, if the height of the conveyor 30 is adjusted so that the scrap falls at a point that is angled nearly flat, the installation area of ​​the electromagnet 12 can be further reduced. However, if the scrap falls at a point that is angled nearly flat, some of the non-magnetic objects 21 may get caught on the light magnetic objects 22 or heavy magnetic objects 23 that are attracted to the rotating drum 13, and may be carried onto the rotating drum 13 and fall into zone Z2. As described above, the size of the gap between the conveyor 30 and the rotating drum 13 and the height of the conveyor 30 are set so that the non-magnetic objects 21 and the magnetic objects (light magnetic objects 22 and heavy magnetic objects 23) can be separated with high accuracy.

[0044] As described above, in the overfeed-type drum-type magnetic separator 40 of this embodiment, scrap is dropped from the conveyor 30 onto the rotating drum 13, and the non-magnetic materials 21 in the scrap are dropped in the direction opposite to the rotation of the rotating drum 13. Meanwhile, the light magnetic materials 22 and heavy magnetic materials 23 are attracted to the rotating drum 13 and transported to the opposite side of the conveyor 30 around the drum shaft 11. Thereafter, the heavy magnetic materials 23 fall due to gravity, resisting the magnetic force, partway through the range of the magnetic force of the electromagnet 12, while the light magnetic materials 22 fall by reaching a range beyond the magnetic force. In this way, in this embodiment, a single magnetic separator can separate scrap into three types: non-magnetic materials, light magnetic materials, and heavy magnetic materials.

[0045] In the drum-type magnetic separator 40 according to this embodiment, the electromagnets 12 must be provided over a range in the circumferential direction, at least from the position where the light magnetic materials 22 and the heavy magnetic materials 23 are attracted to the rotating drum 13 after falling from the conveyor 30 to a position where the heavy magnetic materials 23 fall from the rotating drum 13 and only the light magnetic materials 22 can be attracted to the rotating drum 13 (for example, a position beyond the second partition plate 32). As described above, the area of ​​the electromagnets along the circumferential direction can be made shorter than in the first embodiment, so the range in which the electromagnets exist along the circumferential direction is set to more than 180°, and preferably 210° or more.

[0046] As described above, in this embodiment, the light magnetic objects 22 and the heavy magnetic objects 23 are attracted to the rotating drum 13 while dropping from the conveyor 30, so a greater magnetic force is not required during attraction compared to the first embodiment. However, as in the first embodiment, the magnetic force may be different when the heavy magnetic objects 23 are attracted and when they are dropped. The method for making the magnetic force from the electromagnet different is the same as in the first embodiment. Also, as in the first embodiment, a vibrating conveyor such as a vibrating feeder is preferable for the conveyor 30 that transports the scrap. However, in an environment where the scrap is transported flat rather than in a pile, a normal conveyor may be used.

[0047] In the drum-type magnetic separator 40 according to this embodiment, non-magnetic materials 21 flow and fall along the surface of the rotating drum 13 in the direction opposite to the rotation direction of the rotating drum 13. In the example shown in FIGS. 4 and 5, the falling non-magnetic materials 21 collide with the first partition plate 31, so the first partition plate 31 is installed close to the rotating drum 13. On the other hand, if zone Z1 is set to a wide area, and the falling non-magnetic materials 21 do not fall into zone Z3, the first partition plate 31 does not need to be installed close to the rotating drum 13. In the example shown in FIG. 4, the first partition plate 31 is installed diagonally and functions like a chute that drops the non-magnetic materials 21. On the other hand, the first partition plate 31 may be installed vertically, provided that the falling non-magnetic materials 21 fall into zone Z1 without colliding with the first partition plate 31. The second partition plate 32 is the same as in the first embodiment.

[0048] (Other embodiments) In the first and second embodiments described above, examples were described in which scrap was sorted into three types: non-magnetic materials 21, light-weight magnetic materials 22, and heavy-weight magnetic materials 23. However, scrap may be sorted into four types: non-magnetic materials, light-weight magnetic materials, medium-weight magnetic materials, and heavy-weight magnetic materials. In this case, a drop area for medium-weight magnetic materials is provided between the drop areas for light-weight magnetic materials and the drop area for heavy-weight magnetic materials. Then, the light-weight magnetic materials, medium-weight magnetic materials, and heavy-weight magnetic materials are attracted to the rotating drum using the method of the first or second embodiment, and the heavy-weight magnetic materials fall first by gravity, followed by the medium-weight magnetic materials.

[0049] Although the type and size of heavy magnetic objects transported on the conveyor can be predicted to some extent, there may be cases where heavy objects are mixed in randomly. In such cases, the magnetic force of the electromagnet may be insufficient, and the objects may not be attracted to the rotating drum and may fall along with the non-magnetic objects. Therefore, a camera may be installed to photograph the scrap transported on the conveyor, and the weight of the heavy magnetic objects may be estimated from the captured images. Then, if it is confirmed from the captured images that a heavier magnetic object than initially expected is being transported, the magnetic force of the electromagnet may be adjusted in real time to increase it.

[0050] Furthermore, in the first and second embodiments described above, the first partition plate 31 and the second partition plate 32 were installed to separate the non-magnetic objects 21, the light magnetic objects 22, and the heavy magnetic objects 23. However, if these objects can be separated, these partition plates may not be installed. For example, a hopper or the like may be installed as a receiving tray near the drop point so that the objects can be directly accommodated. However, since heavy magnetic objects come in a variety of weights and the position at which they fall from the rotating drum varies depending on their weight, a large storage area must be secured when accommodating heavy magnetic objects.

[0051] A specific example in which a partition plate is not used will be described below. FIG. 6(a) is a diagram showing an example of a scrap sorting device that separates light magnetic objects from heavy magnetic objects without using a partition plate. FIG. 6(b) is an enlarged view of the scrap sorting device shown in FIG. 6(a) as viewed from the direction of arrow A. In the examples shown in FIGS. 6(a) and 6(b), a collection box 61 and a transport conveyor 62 are installed without using a second partition plate 32. The collection box 61 collects the light magnetic objects 22 that have fallen from the rotating drum 13. Meanwhile, as shown in FIG. 6(b), the heavy magnetic objects 23 fall from the rotating drum 13 onto the transport conveyor 62, which then transports the heavy magnetic objects 23 as they are.

[0052] The disclosure of this embodiment includes the following configurations and methods.

[0053] (Configuration 1) A scrap sorting device that sorts out non-magnetic objects, light magnetic objects having a weight less than a reference weight, and heavy magnetic objects having a weight equal to or greater than the reference weight from scrap, a conveyor for transporting the scrap; a drum-type magnetic separator that attracts light magnetic materials and heavy magnetic materials in the scrap transported on the conveyor onto a rotating drum using a magnet fixed inside; and a gap is provided between the conveyor and the drum-type magnetic separator to allow the non-magnetic material to pass through; When the scrap is transported on the conveyor toward the drum-type magnetic separator, non-magnetic materials in the scrap fall into the gap, and light and heavy magnetic materials in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, after which the heavy magnetic materials fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic materials fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet.

[0054] (Configuration 2) a first partition plate for preventing the non-magnetic objects from falling into the area where the lightweight magnetic objects fall; a second partition plate for preventing the heavy magnetic objects from falling into the area where the light magnetic objects fall; and 2. The scrap sorting device according to claim 1, wherein the second partition plate is installed so as to prevent collision of the lightweight magnetic objects attracted to the rotating drum. (Configuration 3) 3. The scrap sorting device according to claim 1, wherein the heavy magnetic objects are transported onto the rotating drum and dropped from the rotating drum between the time when the heavy magnetic objects reach the same height as the drum axis of the rotating drum and the time when the heavy magnetic objects reach the lowest position of the rotating drum. (Configuration 4) A scrap sorting device according to any one of configurations 1 to 3, characterized in that the magnets are installed in the circumferential direction of the drum-type magnetic separator over a range from a position where the magnets attract at least the light magnetic objects and the heavy magnetic objects to a position where the heavy magnetic objects fall and only the light magnetic objects can be attracted to the rotating drum.

[0055] (Configuration 5) 5. A scrap sorting device according to any one of configurations 1 to 4, characterized in that the magnetic force at the position where the light magnetic objects and heavy magnetic objects are attracted is greater than the magnetic force at the position where the heavy magnetic objects fall. (Configuration 6) 6. The scrap sorting device according to any one of configurations 1 to 5, wherein the light magnetic objects and the heavy magnetic objects are attracted and adsorbed to the rotating drum by magnetic force before dropping from the conveyor. (Configuration 7) 6. The scrap sorting device according to any one of configurations 1 to 5, wherein the light magnetic objects and the heavy magnetic objects are dropped from the conveyor and attracted to the rotating drum.

[0056] (method) A scrap sorting method using a scrap sorting device having a conveyor for transporting scrap, and a drum-type magnetic separator that attracts light magnetic objects having a reference weight less than a reference weight and heavy magnetic objects having a reference weight or more in the scrap transported on the conveyor onto a rotating drum using a magnet fixed inside, a gap is provided between the conveyor and the drum-type magnetic separator to allow non-magnetic materials in the scrap to pass through; A scrap sorting method characterized by the following: when the scrap is transported on the conveyor toward the drum-type magnetic separator, non-magnetic materials in the scrap fall into the gap, light magnetic materials and heavy magnetic materials in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, and then the heavy magnetic materials are allowed to fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic materials fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet. [Explanation of symbols]

[0057] 1, 4 Scrap sorting device 10, 40 Drum-type magnetic separator 11 Drum shaft 12 Electromagnet 13 Rotating drum 21 Non-magnetic materials 22 Lightweight magnetic materials 23 Heavy magnetic materials 30 Conveyor 31 First partition 32 Second partition

Claims

1. A scrap sorting device that sorts out non-magnetic objects, light magnetic objects having a weight less than a reference weight, and heavy magnetic objects having a weight equal to or greater than the reference weight from scrap, a conveyor for transporting the scrap; a drum-type magnetic separator that attracts light magnetic materials and heavy magnetic materials in the scrap transported on the conveyor onto a rotating drum using a magnet fixed inside; and a gap is provided between the conveyor and the drum-type magnetic separator to allow the non-magnetic material to pass through; When the scrap is transported on the conveyor toward the drum-type magnetic separator, non-magnetic materials in the scrap fall into the gap, and light and heavy magnetic materials in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, after which the heavy magnetic materials fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic materials fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet.

2. a first partition plate for preventing the non-magnetic objects from falling into the area where the lightweight magnetic objects fall; a second partition plate for preventing the heavy magnetic objects from falling into the area where the light magnetic objects fall; and 2. The scrap sorting device according to claim 1, wherein the second partition plate is installed so as to prevent light magnetic objects attracted to the rotary drum from colliding with the second partition plate.

3. 3. A scrap sorting device according to claim 1, wherein the heavy magnetic objects are transported onto the rotating drum and dropped from the rotating drum between the time when the heavy magnetic objects reach the same height as the drum axis of the rotating drum and the time when the heavy magnetic objects reach the lowest position of the rotating drum.

4. 3. The scrap sorting device according to claim 1, wherein the magnets are installed in a range in the circumferential direction of the drum-type magnetic separator from a position where the magnets attract at least the light magnetic objects and the heavy magnetic objects to a position where the heavy magnetic objects fall and only the light magnetic objects can be attracted to the rotating drum.

5. 3. The scrap sorting device according to claim 1, wherein the magnetic force at the position where the light magnetic objects and the heavy magnetic objects are attracted is greater than the magnetic force at the position where the heavy magnetic objects fall.

6. 3. The scrap sorting device according to claim 1, wherein the light magnetic objects and the heavy magnetic objects are attracted to and adsorbed onto the rotating drum by magnetic force before dropping from the conveyor.

7. 3. The scrap sorting device according to claim 1, wherein the light magnetic objects and the heavy magnetic objects are dropped from the conveyor and attracted to the rotating drum.

8. A scrap sorting method using a scrap sorting device having a conveyor for transporting scrap, and a drum-type magnetic separator that attracts light magnetic objects having a reference weight less than a reference weight and heavy magnetic objects having a reference weight or more in the scrap transported on the conveyor onto a rotating drum using a magnet fixed inside, a gap is provided between the conveyor and the drum-type magnetic separator to allow non-magnetic materials in the scrap to pass through; A scrap sorting method characterized by the following: when the scrap is transported on the conveyor toward the drum-type magnetic separator, non-magnetic materials in the scrap fall into the gap, light magnetic materials and heavy magnetic materials in the scrap are attracted to the rotating drum and transported by the drum-type magnetic separator to the maximum height of the rotating drum, and then the heavy magnetic materials are allowed to fall from the rotating drum by gravity against the magnetic force of the magnet, and the light magnetic materials fall from the rotating drum by reaching an area where they cannot be attracted by the magnetic force of the magnet.

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