JP2001219093A - Classifying method and classifying device for structure including rare earth magnet and ferromagnetic material - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method and device for classifying rare earth magnets and other ferromagnetic materials by utilizing a difference between Curie temperatures. SOLUTION: The method and device for magnetically separating the mixtures composed of the magnets and the ferromagnetic materials to the materials having the Curie temperature below a heating temperature and the materials having the Curie temperature exceeding the heating temperature by heating these mixtures to the intermediate temperature of the corresponding Curie temperatures by utilizing the difference in their Curie temperatures are provided. The different ferromagnetic materials are heated under the difference between the Curie temperatures and are then separated to the grains to be magnetically attracted and the grains not to be magnetically attracted, by which the classifying of the ferromagnetic materials from each other is made possible.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and apparatus for separating a structure containing a rare earth magnet and a ferromagnetic material by utilizing a difference in Curie temperatures between the structures.

[0002]

2. Description of the Related Art In the separation process of waste electric / electronic equipment recycling, ferromagnetic materials such as permanent magnets and metals adhered to the permanent magnet and exhibiting ferromagnetism are used before waste electric / electronic equipment enters a crushing step. Sorted by hand. on the other hand,
Conventionally, as a method for separating magnetic substance groups, for example, Japanese Patent Laid-Open No. 5-2
A magnetic sorting method as disclosed in Japanese Patent No. 69402 is used to separate magnetic components that are magnetically attracted from magnetic components that are not magnetically attracted. Similarly, for example, in a process of separating a ferromagnetic material such as scrap iron from a non-ferromagnetic material such as plastic, these are separated by using magnetic attraction of a magnet.
Further, as disclosed in, for example, Japanese Patent Publication No. 7-106327, a ferromagnetic ferrite particle having different characteristics is heated to fix a ferrite particle having high characteristics (equivalent to a high Curie temperature) to the inside of the magnet. A method is employed in which a magnetic roll is magnetically adsorbed in a chain shape in the radial direction on the outer peripheral surface of a magnetic roll and is taken out by a scraper plate to perform classification. Although the patent describes ferrite as a ferromagnetic material in detail, it does not deal with the distinction between rare earth magnets and ferromagnetic materials.

[0003]

The reason why members using permanent magnets are manually separated before the waste electric / electronic equipment is put into the crushing step in the waste electric / electronic equipment recycling separation step is that the crushing is performed. This is because when the objects are classified using a drum or the like having openings of various sizes provided on the orbital surface, the crushed permanent magnets magnetically attract the drum openings to close the openings, thereby significantly reducing the classification function. Further, since the permanent magnet and the scrap iron are not currently properly separated, the structure made of the scrap iron or the like magnetically attracted to the permanent magnet also has a problem in classifying that the opening has an action of closing the opening. there were. Therefore, in order to solve this problem, it was necessary to separate permanent magnets and scrap iron, but there was no suitable method and apparatus. Further, in order to use expensive rare earth magnets as resources, it was necessary to separate them from scrap iron and the like, but there was no suitable method and apparatus. Separation of permanent magnets is described in JP-A-5-26.
Although it is possible to use a magnetic separator similar to that disclosed in Japanese Patent No. 9402, a ferromagnetic material such as scrap iron is also attracted to the magnet together with the permanent magnet. Was.

At present, as permanent magnets, Ba ferrite, Sr ferrite, alnico, Sm-Co, Nd-Fe-B
Systems and bond systems in which these are embedded in resins, plastics and the like have been put to practical use. Among them, Nd-Fe-
B-type permanent magnets with high magnet properties up to (BH) max = 50MGOe or more are commercially available.
Demand is increasing for higher performance. For this reason, it is expected that the number of waste electric / electronic devices using the magnets will increase in the future, and it is substantially difficult to manually cope with the sorting process. Therefore, various permanent magnets, especially Nd-F
Development of a method and apparatus for separating eB-based permanent magnets and ferromagnetic materials such as scrap iron is urgently required.

[0005] In addition, harmful gas may be generated by heating the resin, plastic and the like adhering to the crushed ferromagnetic material.
As described in Japanese Patent No. 6327, it is not preferable to collectively heat the fractionated material. Also,
Members of various materials such as plastic besides metal are arranged around the permanent magnet / ferromagnetic material structure in the equipment.
At the time of crushing, these various member pieces adhere to the permanent magnet / ferromagnetic material structure. Therefore, these adhering substances are separated at the time of separation, but in the proposal of the conventional magnetic separation method, once the magnet is attracted, only the magnetically fixed state is set. There is a problem that it is not possible to remove the plastic or the like sandwiched in the middle. In addition, the size and shape after crushing are various, and the weight of the material that is not magnetically attracted causes the material that is magnetically attracted to be relatively small to be fixed and cannot be separated by magnetic adsorption. There is a problem that cannot be reduced.

[0006]

According to the present invention, there is provided a method for separating a rare earth magnet having a first Curie temperature and a first rare earth magnet.
Heating a structure containing a ferromagnetic material having a second Curie temperature higher than the Curie temperature to an intermediate temperature between the first and second Curie temperatures; and Separating the ferromagnetic material by magnetic attraction and transporting the ferromagnetic material to the first shooter, wherein the ferromagnetic material having a second Curie temperature higher than the first Curie temperature is provided to the first shooter by the first Curie. A structure including a rare earth magnet having a temperature is collected in a second shooter.

Further, in the above separation method, the rare earth magnet has Nd ₂ Fe ₁₄ B as a main phase.

[0008] The separation apparatus according to the present invention comprises: means for conveying a structure containing a rare earth magnet having a different Curie temperature and a ferromagnetic material; means for heating the structure to an intermediate temperature between the different Curie temperatures; Means for magnetically attracting the ferromagnetic material from the heated structure.

Further, in the above-mentioned separation apparatus, electromagnetic induction is used as a heating means.

Further, in the above-mentioned separation apparatus, a non-uniform magnetic field is applied as a magnetic attraction means. Further, it is provided that the means for applying the non-uniform magnetic field is a group of magnets whose magnetic pole directions are not aligned.

Further, in the above-mentioned separation apparatus, an exciter is connected to the transport means.

[0012]

DESCRIPTION OF THE PREFERRED EMBODIMENTS Embodiment 1 By heating a structure containing a rare earth magnet and a ferromagnetic material having different Curie temperatures to an intermediate temperature between the Curie temperatures of each other, the ferromagnetic material having a Curie temperature exceeding the heating temperature has a property of being magnetically attracted to the magnet. On the other hand, rare earth magnets having a Curie temperature below the heating temperature lose their magnetic attraction properties. In this state, by approaching the magnet to the surface of the conveyor belt arranged in the middle by the magnetic attraction force of the magnet, a ferromagnetic material having a Curie temperature higher than the heating temperature and a rare earth magnet having a Curie temperature lower than the heating temperature are separated. Is done. By heating by electromagnetic induction, a conductive rare earth magnet / ferromagnetic material structure can be heated without directly heating an insulating resin, plastic, or the like. By applying a method of applying a non-uniform magnetic field to the magnetically attracted material, the material swings, and the material that is not magnetically attracted attached to the magnetically attracted material is wiped off. The magnetic attraction is made non-uniform by configuring the magnet for magnetic attraction to be composed of a group of magnets whose magnetic pole directions are not aligned. By using a method in which vibration is applied when the heated material approaches the magnet for magnetic attraction, the restraint of the material whose movement has been hindered by the material that is not magnetically attracted is released, and the material can be magnetically attracted.

[0013]

[Embodiment 1] FIG. 1 is a schematic diagram of an apparatus for implementing the present invention. In the examples, Nd, Fe, a permanent magnet having a Curie temperature of about 300 ° C. containing B as a main component, and scrap iron having a Curie temperature of about 600 ° C. containing Fe as a main component were crushed by a crusher to have a particle size of approximately 10 mm or less. A rare earth permanent magnet / ferromagnetic material structure 1 made of a permanent magnet and scrap iron was used. This was supplied from the hopper 2 onto the conveyor belt (1) 3, and was conveyed to the heating device 4 which heats the structure 1 above the Curie temperature of the permanent magnet (about 400 ° C. in the experiment) by a heating element. In the process in which the heated structure 1 reaches the second shooter 5, a magnet 7 for magnetic attraction is arranged via a conveyor belt (2) 8, and scrap iron is removed by the magnetic attraction of the magnet 7 to the conveyor belt (2). 8
And was conveyed together with the belt 8. In this process, the permanent magnet was left on the conveyor belt (1) 3 and was collected as the material (1) 6 in the second shooter 5. On the other hand, the scrap iron adhering to and conveyed to the conveyor belt (2) 8 is separated from the conveyor belt (2) 8 until the magnetic attraction force of the magnetic attraction magnet 7 is weakened, and the material (2) is transferred to the first shooter 9. Collected as 10. As described above, the present apparatus was able to separate a permanent magnet and a rare earth permanent magnet / ferromagnetic material structure made of scrap iron using the present apparatus.

The transport belt (1) 3 and the transport belt (2)
8 is made of stainless steel because it does not hinder magnet attraction and can be heated. The separation time was shortened by increasing the transport speed. In order to reduce the time required to raise the temperature above the Curie temperature, the temperature of the heating element is set high, and the temperature of the structure is counted using a radiation thermometer to reach the temperature above the Curie temperature (400 ° C in the experiment). Adjusted to be. An Nd-Fe-B permanent magnet having an energy product (BH) max = 30MGOe is used as the magnet 7 for magnetic attraction, and is demagnetized by temperature rise due to radiant heat from the heated rare earth permanent magnet / ferromagnetic material structure 1. In order to suppress this, a heat insulating material having a thickness of about 5 mm was arranged between the magnet 7 for magnetic attraction and the conveyor belt (2) 8. In this embodiment, the distance between the surface of the conveyor belt (2) 8 facing the rare earth permanent magnet and the ferromagnetic material structure and the magnetic pole surface of the magnet for magnetic attraction is 10 mm, and the conveyor belt (1) 3 The distance between the surfaces facing the conveyor belt (2) 8 was 20 mm.

Embodiment 2 FIG. FIG. 2 is a schematic diagram of a separation apparatus implemented using a high-frequency heating furnace 13 as a heating method of the present invention. In Example 2, in order to heat the rare earth permanent magnet / ferromagnetic material structure 1 by electromagnetic induction by a high-frequency coil, a heat-resistant rubber sheet was used as an insulating material for the transport belt (3) 12, but the temperature was raised. Glass wool was attached to the surface to avoid direct contact with the rare earth permanent magnet / ferromagnetic material structure 1. Also in the heating method, the rare earth permanent magnet / ferromagnetic material structure 1 used in the first embodiment was used for 40 times.
It could be heated to 0 ℃ or more, and Nd-Fe-B magnet and scrap iron could be separated.

The temperature of the material magnetically attracted to the conveyor belt (2) 8 is lower than that of the material located on the conveyor belt (3) 12, and the material is located via the conveyor belt (3) 12 with the material. Heating of the high-frequency heating furnace 13 by electromagnetic induction is performed by the conveyor belt (3) 1.
It turned out that it works effectively on the material above No. 2. This phenomenon is caused by the suppression of the decrease in the magnetic force due to the temperature rise of the magnet for magnetic attraction 7 and the suppression of the decrease in the magnetic force of the material due to the suppression of the temperature rise of the material magnetically attached to the surface of the conveyor belt (2) 8 (ie, It was effective in suppressing the decrease in adhesive force).

Embodiment 3 FIG. FIG. 3 is a schematic view of a sorting apparatus using a magnetic attraction magnet 14 including a magnet arrangement in which the directions of magnetic poles are reversed, implemented in the present invention. In this embodiment, an Nd-Fe-B permanent magnet rod (10 mm × 10 m) having an energy product (BH) max = 30 MGOe
m × 50 mm) were arranged at equal intervals while reversing the direction of the magnetic poles. Other specifications are the same as those in the first embodiment. Also in the method using the magnet for magnetic attraction, scrap iron having a Curie temperature of 400 ° C. or more can be magnetically attracted from the heated rare-earth permanent magnet / ferromagnetic material structure 1 onto the surface of the transport belt 2. -Fe-B magnet and scrap iron could be separated. When the magnet 14 for magnetic attraction according to the present embodiment is used, the direction of the magnetic force lines is reversed on the surface of the conveyor belt (2) 8 as compared with the case where the magnetic poles are aligned and aligned (Example 1). It was observed that the scrap iron fluctuated to equalize. As a result, the Nd-Fe-B permanent magnet sandwiched between the eight surfaces of the conveyor belt (2) and the scrap iron was released from the adhesion, and the ability to separate the magnet and scrap iron was improved.

Embodiment 4 FIG. FIG. 4 shows a second embodiment implemented in the present invention.
FIG. 4 is a schematic diagram of a separation apparatus that utilizes excitation of a mixture during transportation to a shooter 5. Further, FIG. 5 shows a portion for exciting the rare-earth permanent magnet / ferromagnetic material structure 1 (X part in FIG. 4).
FIG. The exciter 15 has a rotating member having blades provided radially, and has a mechanism for flipping up the transport belt (1) 3 when the blades rotate. Other specifications are the same as those in the first embodiment. Even when the exciter is provided, scrap iron having a Curie temperature of 400 ° C. or more can be magnetically attracted from the heated rare-earth permanent magnet / ferromagnetic material structure 1 onto the surface of the conveyor belt (2) 8. , Nd-Fe
-The B magnet and scrap iron could be separated. With the use of the exciter 15 according to the present embodiment, as schematically shown in FIG.
The scrap iron 18 which is magnetically attracted and leaked between the -Fe-B magnet particles and the conveyor belt (1) 3 is also easily magnetically attracted by the disturbed arrangement of the blades, so that the sorting leakage is reduced.

Embodiment 5 FIG. FIG. 6 is a schematic view of a sorting apparatus according to the present invention, in which the magnetic attraction magnet 14 is disposed inside the roller 11. Transfer the magnet 14 for magnetic attraction to the transport belt 20
Are arranged inside the roller 11 which rotates (however, the magnet may be revolved around the rotation axis by the rotation of the roller, or may be arranged and moved so as to rotate). Rare-earth permanent magnet / ferromagnetic material structure 1 is described in Example 1.
It has the same specifications as the ferromagnetic material used for the above. Conveyor belt 20
The upper part of the rare earth permanent magnet / ferromagnetic material structure 1 is heated by a heating furnace 19 capable of radiating heat along the conveyance path so that the temperature is measured at 400 ° C. by a radiation thermometer.
Was moved to the roller 11 inside. Scrap iron having a Curie temperature exceeding 400 ° C. adheres to the belt surface magnetically while the conveyor belt 20 is in contact with the roller 11 due to the magnetic attraction of the magnet 14 for magnetic attraction, while reducing the Curie temperature below 400 ° C. The Nd—Fe—B material is not magnetically attracted by the magnetic attraction magnet (14). For this reason, the scrap iron that has been magnetically attracted adheres to the transport belt 20 while the transport belt is in contact with the rollers, and is further transported.
On the other hand, the Nd-Fe-B material that is not attracted by the magnetic force separates from the transport belt 20 after the transport belt 20 folds the rollers. Therefore, the shooter 1, vertically below these separation points,
Even in the apparatus using the method of arranging 2, the Nd-Fe-B material and the scrap iron could be separated.

Although the embodiments of the present invention have been described in detail above, the effectiveness of the present invention is not changed by the following contents. That is, in each of the embodiments described in detail, the example in which the transport belt (1) 3 is moved in the horizontal direction is shown, but it is confirmed that the material can be moved on the belt by its own weight by tilting the belt. This method can be used.

In the first embodiment, the non-magnetic stainless steel is used as the material of the conveyor belt (2) 8. However, the heat radiation is improved by using a material having high thermal conductivity such as copper, and the magnetic adsorbing material is improved. It is possible to improve the sorting ability by suppressing the temperature decrease and the temperature increase of the magnetic attraction magnet. In the first embodiment, the distance between the surface of the conveyor belt (2) 8 facing the mixture and the magnetic pole surface of the magnetic attraction magnet is 10 mm, and the conveyor belt (1)
Although the distance between the surfaces of the belt 3 and the conveyor belt (2) 8 is set to 20 mm, the distance between the surfaces can be increased by using a magnet having a higher magnetic force as the magnet for magnetic attraction.

According to the high-frequency heating used in the second embodiment,
For example, resin, plastic, or the like mixed in the rare-earth permanent magnet / ferromagnetic material structure does not become a heat source, and generation of harmful gas can be suppressed. In addition, the crushed material of the equipment member using the permanent magnet includes a non-ferromagnetic member and a nonmetal such as resin and plastic. Although it is not possible to separate these with the apparatus shown in the embodiment of the present invention alone, if the magnetic particles are collected without heating the particles collected in the first shooter by the apparatus of the present invention, the permanent magnet and others can be separated. Can be separated.

In the third embodiment, an arrangement in which the poles of a bar magnet are reversed is used as a magnet for generating a non-uniform magnetic field. However, a method of making the strength direction of a magnetic field generated by an electromagnet time-dependent, and RBa ₂ Cu ₃ O7 (R is a rare earth element such as Y)
A superconductor obtained by cooling an oxide superconductor represented by a phase represented by the following formula in a magnetic field to form a superconductor can be used as a magnetic attracting magnet as a fixed or rotating object.

Further, in the fourth embodiment, as a method of excitation, a mechanism for flipping up the transport belt when the rotating member having the radially arranged blades rotates is used, but the vibration of the piezoelectric body or the magnetostrictive element is used for the excitation. Can also be used.

[0025]

As described above, according to the present invention, a structure including a rare-earth permanent magnet and a ferromagnetic material having different Curie temperatures is heated to an intermediate temperature between the Curie temperatures of each other to be magnetically attracted. Since the material and the material are not magnetically attracted, it is possible to separate them, and it is possible to provide a separation device that does not require manual operation.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a separation apparatus that performs a separation method of the present invention.

FIG. 2 is a schematic diagram of a separation apparatus using a high-frequency heating furnace as a heating method of the present invention.

FIG. 3 is a schematic diagram of a separation apparatus using a magnet for magnetic attraction including a magnet arrangement with reversed magnetic poles implemented in the present invention.

FIG. 4 is a schematic view of a separation apparatus utilizing excitation of a mixture during transportation to a second chute implemented in the present invention.

FIG. 5 is an enlarged schematic view of a portion where the ferromagnetic material mixture indicated by X in FIG. 4 is vibrated.

FIG. 6 is a schematic diagram of a sorting apparatus in which a magnet for magnetic attraction implemented in the present invention is disposed inside a roller.

[Explanation of symbols]

1 rare earth permanent magnet / ferromagnetic material structure, 2 hopper, 3 conveyor belt (1), 4 heating device,
5 second shooter, 6 material (1), 7 magnet for magnetic attraction, 8 conveyor belt (2), 9 first shooter, 10 material (2), 11 roller, 12
Conveyor belt (3), 13 high-frequency heating furnace, 14 magnet for magnetic attraction, 15 exciter, 16 Nd-Fe-B permanent magnet, 17 scrap iron, 18 scrap iron, 19
Heating furnace, 20 conveyor belt.

 ──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Ken Araki 2-3-2 Marunouchi, Chiyoda-ku, Tokyo Mitsui Electric Co., Ltd. (72) Inventor Shigehiro Yabu 2-3-2 Marunouchi, Chiyoda-ku, Tokyo 3 Rishi Electric Co., Ltd.

Claims (7)

[Claims] 1. A structure comprising a rare-earth magnet having a first Curie temperature and a ferromagnetic material having a second Curie temperature higher than the first Curie temperature, wherein a structure comprising the first and second Curie temperatures is provided. A step of heating to an intermediate temperature, and a step of selecting the ferromagnetic material from the heated structure by magnetic attraction and transporting the ferromagnetic material to a first shooter, wherein a second temperature higher than the first Curie temperature is provided. A structure including a rare earth magnet and a ferromagnetic material, wherein a ferromagnetic material having a Curie temperature is collected in a first shooter, and a structure including a rare earth magnet having a first Curie temperature is collected in a second shooter. How to sort things. 2. The method for separating a structure containing a rare earth magnet and a ferromagnetic material according to claim 1, wherein the rare earth magnet has Nd ₂ Fe ₁₄ B as a main phase. 3. A means for transporting a structure containing a rare earth magnet having a different Curie temperature and a ferromagnetic material, a means for heating the structure to an intermediate temperature between the different Curie temperatures, Means for magnetically attracting the ferromagnetic material from the inside thereof. 4. The separation apparatus according to claim 3, wherein electromagnetic induction is used as the heating means. 5. The separation apparatus according to claim 3, wherein a non-uniform magnetic field is applied as the magnetic attraction means. 6. The sorting apparatus according to claim 5, wherein the means for applying the non-uniform magnetic field is a group of magnets whose magnetic pole directions are not aligned. 7. The separation apparatus according to claim 3, wherein an exciter is connected to the transport means.