JP2012132052A - Rare earth magnet recovery method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a rare earth magnet recovery method, which enables the recovery of a resin-free rare earth magnet from a product containing the rare earth magnet that is integrated with a resin.SOLUTION: In the method for the recovery of the rare earth magnet from the product containing the rare earth magnet integrated with a resin, the rare earth magnet integrated with the resin is treated with hot water to decompose and detach the resin, and is recovered.

Description

  The present invention relates to a method for collecting rare earth magnets.

  Rare metals (rare metals) and rare earths (rare earths) are widely used from general household electrical appliances to computer peripherals, electronic devices, automobiles, medical devices and the like. In particular, rare earth magnets such as rare earth magnet alloys containing rare earth such as Nd (neodymium) and Dy (dysprosium) have good magnetic performance, and are used in motors for generators, actuators for hard disks, motors and rotors in washing machines, etc. It is used.

  In order to use these rare substances, it is important to secure them in a stable manner, and demands for recycling are increasing due to social constraints due to the uneven distribution of resources and price increases due to increased demand. ing.

  On the other hand, the Home Appliance Recycling Law was enforced in April 2001, and it is obliged to recycle 4 items of home appliances such as air conditioners, TVs, refrigerators and washing machines. In the recycling process of these home appliances, metals such as iron, copper, and aluminum and resin waste such as plastic are separately collected. For example, as shown in FIG. 4, waste home appliances such as washing machines are crushed as they are, and metal and resin waste are separated and collected by machine division using a sorting method using magnetic force, eddy current, specific gravity, and the like.

  Under such circumstances, recently, a compressor / rotor or motor / rotor including high-performance rare earth magnets has been used in washing machines and air conditioners. In particular, when rare earth magnets are used while being fixed to a resin or the like, the resin fixed to the rare earth magnets is removed by a conventional method such as manual disassembly or pulverization to remove the rare earth magnets. It is difficult to recover. In the case of manual work or mechanical disassembly, it is difficult to cleanly separate the resin for labor, and if it is pulverized, it is difficult to separate it from metal components such as iron.

  As a collection technique reported so far, there is a technique described in Patent Document 1. The technique described in Patent Document 1 is a technique for recovering rare earth elements from scrap or sludge generated in the magnet machining process of rare earth magnets.

JP 2002-60863 A

  However, this recovery technique is a rare earth element recovery technique for recovered rare earth magnet scrap and sludge. Since rare earth magnets contained in home appliances such as washing machines and air conditioners are only a few percent of the home appliances alone, in order to recover rare earth elements, first from the plastic or steel plate that is the housing of home appliances It is necessary to selectively collect rare earth magnets.

  In addition, when the rare earth magnets included in the household electrical appliance are integrated with the resin, such as being covered (sealed) with the resin or the resin being fixed, as described above. It is necessary to remove the resin from the rare earth magnets.

  The present invention has been made in view of the circumstances as described above, and a method for recovering rare earth magnets capable of recovering rare earth magnets from which a resin is removed from a product including rare earth magnets integrated with a resin. It is an issue to provide.

  In order to solve the above-described problems, the present invention is a method for recovering rare earth magnets from a product including rare earth magnets integrated with a resin, wherein the rare earth magnets integrated with a resin are hydrothermally treated. Then, the rare earth magnets are recovered by decomposing and peeling the resin.

  The present invention also relates to a method for recovering rare earth magnets from a product including rare earth magnets integrated with a resin, and (a) disassembling the product and recovering rare earth magnets integrated with a resin. And (b) a step of hydrothermally treating the rare earth magnets integrated with the recovered resin to decompose and peel off the resin to recover the rare earth magnets.

  In this method of collecting rare earth magnets, a mesh container containing rare earth magnets integrated with resin is put into a decomposition tank, and after hydrothermal treatment in the decomposition tank, the mesh container is It is preferable that the rare earth magnets are recovered from the mesh container after being taken out from the decomposition tank.

  Moreover, in this method for recovering rare earth magnets, it is preferable that the hydrothermal treatment water contains an alkali metal salt.

  ADVANTAGE OF THE INVENTION According to this invention, the rare earth magnets which removed resin from the product containing the rare earth magnets integrated with resin can be collect | recovered.

It is the flowchart which showed one Embodiment of the collection | recovery method of the rare earth magnets of this invention. It is a schematic diagram of the process flow of a hot water treatment. It is a schematic diagram of another process flow of a hot water process. It is a flowchart of the collection method of the conventional waste household appliance.

  As described above, the present invention is a method for recovering rare earth magnets from a product including rare earth magnets integrated with a resin.

  Examples of products targeted by the present invention include home appliances such as washing machines and air conditioners, but are not particularly limited as long as they include rare earth magnets integrated with a resin. For example, computer peripheral devices, electronic devices, communication devices, automobiles, medical devices, and the like may be used. In addition, the motor and actuator included in the above-described product, and the rotor that is a component of the motor and actuator can also be the product targeted by the present invention. These products include waste products such as used products.

  In the present invention, rare earth magnets include various rare earth metals including rare earth magnets such as samarium cobalt magnets and neodymium magnets, alloys containing them, and rare metals.

  Rare earth magnets integrated with a resin are those in which a rare earth magnet is coated or sealed with a cured resin, or is fixed to a cured resin with or without an adhesive. Things etc. The rare earth magnets are integrated with the resin as a powder or a molded body. When rare earth magnets are integrated with a resin as a molded body, according to the present method, the rare earth magnets can be recovered as a molded body.

  Examples of the resin include thermosetting resins such as unsaturated polyester resins and epoxy resins, but are not limited thereto. The resin may contain an inorganic filler such as calcium carbonate or calcium hydroxide, an inorganic material such as glass fiber, and other components.

  The rare earth magnets integrated with such a resin can be a component member of a product or a component member of a component constituting the product. For example, when the product to be collected is a household electrical appliance such as a washing machine or an air conditioner, the rare earth magnets integrated with the resin can be used as a constituent member of the rotor of the motor constituting the household electrical appliance. When the product to be collected is a motor, the rare earth magnets integrated with the resin can be used as a constituent member of the rotor constituting the motor. When the product is a rotor, rare earth magnets integrated with resin can be used as a constituent member of the rotor. The rotor is configured, for example, by molding a rare earth magnet compact and an iron frame with a thermosetting resin.

  The rare earth magnets integrated with the resin as a constituent member in this manner include members other than resins and rare earth magnets, for example, metal members such as iron and copper, inorganic members such as carbon fibers, and organic members. It may be.

  The present invention recovers rare earth magnets by hydrothermally treating rare earth magnets integrated with resin to decompose and peel the resin. This hot water treatment can be performed on the product itself, or the product can be disassembled and the dismantled product.

  The following description will be made with reference to the flowchart of rare earth magnet recovery in FIG. 1 and the schematic diagram of the process flow of hot water treatment in FIG. The rare earth magnet recovery flowchart of FIG. 1 shows an embodiment of the method for recovering rare earth magnets of the present invention, and an embodiment in the case of disassembling a product and subjecting the disassembled product to hot water treatment It is.

  In the present embodiment, as shown in FIG. 1, first, the product itself starts by disassembling. For example, a machine tool or a jig is used to disassemble a product into parts (parts), and parts containing rare earth magnets including rare earth magnets integrated with resin, and other parts (rare earth magnets) Parts not included).

  This dismantling work is performed on a single product or a part containing rare earth magnets by performing a cutting operation on a rare earth magnet-containing part disassembled up to a part unit using a machine tool or a jig. It can also be separated from other parts. In this case, the part containing rare earth magnets can be classified as a rare earth magnet containing part, and the other parts can be classified as other parts.

  Even when the product is composed of a single part, it can be separated into a part containing rare earth magnets and another part by performing a similar operation such as cutting.

  The above dismantling work can also be performed manually. It is known from the characteristics of the product where the parts containing rare earth magnets or parts containing rare earth magnets exist, so it is easy to selectively select parts containing rare earth magnets or parts containing rare earth magnets. It can be recovered. In the dismantling operation, processing such as crushing and crushing is not performed.

  After the dismantling operation, a demagnetizing step of demagnetizing the rare earth magnet contained in the rare earth magnet-containing component can be performed.

  Next, the recovered rare earth magnet-containing component is treated with hot water.

  In the hot water treatment, first, as shown in FIG. 2, the collected rare earth magnet-containing component 20 is stored in the mesh-like storage body 10, and this mesh-like storage body 10 is put into the decomposition tank 1. Then, hot water treatment is performed. Although the rare earth magnet-containing component 20 can be directly put into the decomposition tank 1 and subjected to hot water treatment, it is possible to take out members such as the rare earth magnets 30 remaining after the hot water treatment by using the mesh container 10. It is preferable because it is easy and efficient.

  The mesh-like storage body 10 has a mesh structure in which water can enter inside, and members such as the rare earth magnets 30 remaining after the rare earth magnet-containing component 20 is hydrothermally treated do not fall out to the outside. Just do it. As the overall structure of the mesh-like storage body 10, for example, a bowl-shaped one with an open top can be adopted.

  The decomposition tank 1 is a pressure vessel having a lid portion 8 and is preferably provided with a quick lid opening / closing mechanism defined by JIS or the like in which the lid portion 8 operates to be freely opened and closed. The lid 8 can be opened and closed by a bolting method, but it is preferable to open and close the lid 8 by a quick lid opening / closing mechanism in view of workability in a large-scale industrial apparatus.

  The hot water treatment is performed according to the following flow. As shown in FIG. 2, water from the water storage tank 2 is pressurized by a pump 3, heated while exchanging heat with a heat medium in a heat exchanger 4, and pressurized hot water is supplied to the decomposition tank 1. . In the decomposition tank 1, the hot water treatment of the rare earth magnet-containing component 20 is performed with pressurized hot water. The hot water discharged from the decomposition tank 1 is cooled while exchanging heat with water supplied from the water storage tank 2 to the decomposition tank 1, and is cooled while exchanging heat with cold water in the heat exchanger 5. The pressure is reduced. Since the depressurized water may contain organic matter and inorganic matter, water treatment such as removal of organic matter and inorganic matter is performed in the water circulation drainage facility 7, and most of the water is supplied to the water tank 2 and circulated. Used, some drained. When the water in the water storage tank 2 is insufficient, water is appropriately replenished from the outside.

  The pressurized hot water supplied to the decomposition tank 1 is, for example, liquid water heated to about 180 ° C. to 350 ° C., and is in a subcritical state. The pressure is, for example, about 2 to 15 MPa.

  The hot water treatment may be performed by continuing to pass the pressurized hot water through the decomposition tank 1, but after passing for a certain period of time, the supply of the pressurized hot water is stopped and the pressurized hot water is supplied as it is. You may carry out by hold | maintaining in the decomposition tank 1. FIG. In this embodiment, since the heat source required for decomposition | disassembly of resin in the rare earth magnet containing components 20 is supplied from this pressurized hot water, it is desirable that the decomposition tank 1 is a heat insulation container.

  The hot water treatment can also be performed by a flow as shown in FIG. Water in the water storage tank 2 is supplied to the decomposition tank 1 by a pump 11. The water supplied to the decomposition tank 1 is pressurized to a predetermined pressure and heated to a predetermined temperature by a heat medium circulating in the jacket 12 provided around the decomposition tank 1. In the decomposition tank 1, the hydrothermal treatment of the rare earth magnet-containing component 20 is performed in a subcritical state at a reaction temperature of 180 ° C. to 350 ° C.

  Hydrolysis of the resin in the rare earth magnet-containing component 20 proceeds by the hot water treatment. As the hydrolysis reaction proceeds, the resin has a low molecular weight, and the resin is removed from the rare earth magnets by separating the resin from the rare earth magnets or partially dissolved in water, thereby separating the rare earth magnets. Even when the resin is fixed to the rare earth magnets via the adhesive, it is possible to remove the resin and the adhesive from the rare earth magnets by eliminating the function as the adhesive by this hot water treatment. When the rare earth magnet-containing component 20 includes a metal member such as iron or an inorganic member such as carbon fiber, these members are also separated from the resin. Moreover, the demagnetization of the rare earth magnet can be partially possible.

  Such hot water treatment is preferably performed with pressurized hot water containing an alkali metal salt such as sodium hydroxide or potassium hydroxide. By including the alkali metal salt, for example, the hydrolysis reaction of the resin can be effectively advanced at a temperature of 180 ° C. to 270 ° C. In addition, valuable materials can be recovered from the decomposition product of the resin.

  After the hot water treatment, the inside of the decomposition tank 1 is cooled to room temperature to about 80 ° C. by reducing the pressure and passing cold water. The decomposition tank 1 can also be naturally cooled.

  After decompression and cooling, the mesh container 10 is dispensed from the decomposition tank 1. The rare earth magnets 30 from which the resin has been removed can be recovered from the discharged mesh-like storage body 10. When the rare earth magnet-containing component 20 contains a metal member such as iron or an inorganic member such as carbon fiber, these members are obtained together with the rare earth magnet 30 with the resin removed. For example, when the rare earth magnet-containing component 20 is a motor rotor, the rotor structure is generally a structure in which a rare earth magnet is inserted into an electromagnetic steel plate (iron frame), and the iron frame and rare earth magnet are integrated after resin separation. It is collected in the state.

  In this embodiment, since processing such as crushing and crushing is not performed in the dismantling operation of the product, and because it is a known product or part, after the resin separation, the rare earth magnets 30 and other metal members or inorganic members Can be separated and collected easily from the appearance. When the rare earth magnet-containing component 20 is a rotor of a motor, after separation of the resin, as described above, the iron frame and the rare earth magnet are in an integrated state, but the magnet shape is mechanically extracted from the iron frame. It is possible to separate and collect the rare earth magnet from the iron frame while maintaining the above (FIG. 1). This extraction may be performed manually or a jig for extraction may be used. Moreover, you may isolate | separate by giving a mechanical vibration. Moreover, if other inorganic members are contained besides an iron frame, it can collect | recover as inorganic waste.

  In the decomposition tank 1 after discharging the mesh-like storage body 10, components in the rare earth magnet-containing component 20 other than those recovered from the mesh-like storage body 10, for example, a decomposition product of the resin together with water are decomposed liquid. Remain as. When the resin contains an inorganic filler such as calcium carbonate or calcium hydroxide or an inorganic substance such as glass fiber, these remain in the decomposition solution as a solid content. This solid content can be recovered as inorganic waste by solid-liquid separation of the decomposition solution by a method such as filtration. The recovered inorganic waste can be reused as an inorganic filler by drying and pulverizing.

  On the other hand, valuable materials can be recovered from the separated filtrate of the decomposition solution. For example, if the resin is an unsaturated polyester resin, a polybasic vinyl monomer copolymer such as a styrene maleic acid copolymer, or a polyester-derived monomer such as a polyhydric alcohol and a polybasic acid can be obtained.

  Other parts after the product is disassembled can be pulverized or crushed as shown in FIG. 1, and can be refined to a particle size of about 10 mm to 15 mm, for example. . After processing such as pulverization or crushing, metal and resin waste can be separated and recovered by mechanical division by a known sorting method using magnetic force, eddy current, specific gravity, wind force, and the like.

  As described above, the rare earth magnets from which the resin is removed can be recovered from the product including the rare earth magnets integrated with the resin. Since the rare earth magnets integrated with the resin are collected by a simple dismantling operation, there is little economic burden and the cost of collecting the rare earth magnets can be reduced. It is also possible to recover the rare earth magnets as a molded body.

  While the present invention has been described based on the embodiments, the present invention is not limited to the above-described embodiments, and various modifications can be made without departing from the scope of the invention. For example, as described above, the hot water treatment can be performed on the product itself without disassembling the product. That is, the product itself is subjected to hot water treatment as the rare earth magnet-containing component shown in FIG. Even in this case, the rare earth magnets from which the resin has been removed can be recovered. It is also possible to recover the rare earth magnets as a molded body.

  Examples of the present invention are shown below, but the present invention is not limited thereto.

<Example 1>
A rotor part containing 12% rare earth magnets, 12% glass fiber and calcium carbonate resin, and 76% steel plate was disassembled from the washing machine, stored in a mesh-like storage body, and put into a decomposition tank. Next, water was supplied to the decomposition tank, heated, and maintained in a subcritical water state at a temperature of 260 ° C. and a pressure of 5 MPa for 2 hours. After naturally cooling to room temperature, the mesh-like storage body was taken out from the decomposition tank, and the rare earth magnet and the steel plate were collected separately. Further, the contents of the decomposition tank were taken out, and glass fibers and calcium carbonate were separated and collected by a known sorting method.
<Example 2>
A rotor part containing 12% rare earth magnets, 12% glass fiber and calcium carbonate resin, and 76% steel plate was disassembled from the washing machine, stored in a mesh-like storage body, and put into a decomposition tank. Subsequently, 1 mol / L sodium hydroxide aqueous solution was supplied to the decomposition tank, heated, and maintained in a subcritical water state at a temperature of 230 ° C. and a pressure of 5 MPa for 2 hours. After naturally cooling to room temperature, the mesh-like storage body was taken out from the decomposition tank, and the rare earth magnet and the steel plate were collected separately. Further, the contents of the decomposition tank were taken out, and glass fibers and calcium carbonate were separated and collected by a known sorting method.

1 Decomposition tank 10 Mesh container 30 Rare earth magnets

Claims (4)

  A method for recovering rare earth magnets from a product including rare earth magnets integrated with a resin, wherein the rare earth magnets integrated with a resin are hydrothermally treated to decompose and peel off the resin, thereby the rare earth magnets. A method for recovering rare earth magnets, characterized in that the magnets are recovered. A method for recovering rare earth magnets from a product including rare earth magnets integrated with a resin,
(A) disassembling the product and collecting rare earth magnets integrated with the resin;
(B) a step of hydrothermally treating the rare earth magnets integrated with the recovered resin to decompose and peel off the resin and recover the rare earth magnets;
A method for recovering rare earth magnets.   A mesh container containing rare earth magnets integrated with resin is put into a decomposition tank, and after hydrothermal treatment in the decomposition tank, the mesh container is taken out of the decomposition tank and stored in the mesh. The method for recovering rare earth magnets according to claim 1, wherein the rare earth magnets are recovered from a body.   The method for recovering rare earth magnets according to any one of claims 1 to 3, wherein the water for the hot water treatment contains an alkali metal salt.

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