JP2000301131A - Treatment method of waste printed circuit board - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the subject treatment method capable of suppressing the amt. of solder mixed into a substrate resin component recovered by treating a printed circuit board to efficiently separate a metal component and the substrate resin component. SOLUTION: A treatment method of a waste printed circuit board is characterized by including a heating process 12 performing the dry distillation of a printed circuit board having a copper foil having solder arranged on at least a part of the surface thereof at 250 deg.C or higher, a grinding process 13 for grinding the dry distillation matter of the printed circuit board obtained in the heating process 12 and a separation process 14 separating the ground matter of the waste printed circuit board obtained in the grinding process into a substrate resin component and a metal component.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION The present invention relates to a method for producing copper foil, solder, and the like from waste printed boards generated from used electrical products and the like, defective products and scraps generated in a manufacturing process.
The present invention relates to a method for separating a metal material of a waste printed circuit board for separating a metal material such as an electronic component.

[0002]

2. Description of the Related Art At present, as a method of disposing of a waste printed circuit board contained in used electric appliances, a method of landfilling a managed disposal site is generally used. Because the controlled disposal site is surrounded by a shielding sheet, even if harmful substances such as lead components derived from solder contained in waste printed circuit boards are eluted with rainwater, the harmful components are prevented from diffusing to the surroundings. be able to.

However, if the shielding sheet is broken, harmful substances may diffuse to the surroundings. Therefore, it is desired to remove harmful components such as solder and make the harmless substance when disposing of the printed circuit board. Was. In addition, printed boards and electronic components mounted on the boards contain valuable metals such as copper, and efficient collection and recycling of these metals have been desired.

[0004] Furthermore, waste printed boards are also generated in the form of defective products and scraps at manufacturing sites related to printed boards, and at present, they are landfilled as described above as industrial waste. There has also been a demand for efficient collection and recycling of valuable metals such as copper contained in waste printed circuit boards.

[0005] Several methods of treating a waste printed circuit board reflecting the above situation have been proposed. For example, as disclosed in JP-A-6-228667, a printed board on which components are mounted is crushed in a coarse crushing step and a fine crushing step, and the obtained crushed material is subjected to a specific gravity separation step to remove a metal material such as copper. There is a method of separating and collecting a part containing a large amount and a part composed of a resin or a filler.

[0006]

However, since the substrate portion of the waste printed circuit board is strong, a large crushing force is required to crush the waste printed circuit board as described above. However, when the waste printed circuit board is crushed using a crushing force that can crush the printed circuit board, the resin component of the board is finely pulverized and the solder is also pulverized. Was difficult to separate.

Similarly, in the case of electronic components, the electronic components are finely pulverized in the pulverizing step, so that it is difficult to separate the electronic components from the resin component of the substrate. In other words, there is a problem that the recovery efficiency of metal materials such as solder and electronic components is low.

In the present invention, in consideration of the above-mentioned problem of the conventional method of processing a waste printed circuit board, the amount of solder mixed in the board resin component recovered in the processing of the printed circuit board is suppressed, and the efficiency is improved. It is an object of the present invention to provide a method for treating a waste printed circuit board that can separate a metal component and a substrate resin component.

Another object of the present invention is to provide a method for separating a metal material from a waste printed circuit board, which efficiently separates the metal material from the waste printed circuit board.

[0010]

According to the present invention, there is provided a heating step of carbonizing a printed circuit board having a copper foil having solder disposed on at least a part of its surface at a temperature of 250 ° C. or more, and the heating step. Waste printing, comprising: a pulverizing step of pulverizing the dry distillate of the printed board; and a separating step of separating the pulverized waste waste board obtained in the pulverizing step into a substrate resin component and a metal component. This is a method for processing a substrate.

Further, the present invention provides a method of manufacturing a waste printed circuit board having at least a metal material under an atmosphere in which the printed circuit board portion of the waste printed board does not burn, or in an atmosphere in which the metal material is not oxidized. A heating step of heating so that the temperature of the waste printed circuit board becomes 250 ° C. or more and less than 500 ° C., and pulverizing so that substantially only the printed circuit board portion of the waste printed circuit board heated in the heating step becomes fragments of a predetermined size or less. Crushing process,
Separation for separating the fragments of the substantially printed circuit board portion pulverized in the pulverizing step and the metal material provided on the waste printed circuit board based on a difference between the size of the fragments and the size of the metal material. And a method for separating a metal material from a waste printed circuit board.

In the present specification, the carbide mainly means a carbide of a substrate resin component or a printed circuit board portion, but of course also includes other carbides.

[0013]

(1) The first embodiment of the present invention will be described below.

According to a first aspect of the present invention, a printed circuit board is heated to 250 ° C.
A heating step of carbonizing at the above temperature, a pulverizing step of pulverizing the dry distillate of the printed board obtained in the heating step so that the solder is not finely cut, and a process of pulverizing the waste printed board obtained in the pulverizing step. The method includes a separation step of separating the pulverized material into a substrate resin component and a metal component.

FIG. 1 is a schematic view of an apparatus for performing a separation step from a heating step. Here, step 12 is a step performed in a heating furnace, step 13 is a step performed in a crusher, and step 13 is a step performed in a sieve. The substrate is separated into a substrate resin component and a metal component.

Normally, electronic components are soldered on a copper foil and mounted on a printed circuit board. However, in the present invention, attention has been paid to the characteristics of copper with which the solder is in contact. In other words, when the temperature of copper becomes high, the rate of dissolution in the solder increases, so by carbonizing the printed circuit board with the solder attached, the interface between the solder and the copper is welded to each other and the adhesion of the solder to the copper foil is improved, Solder bumps are reduced. Therefore, even after the pulverizing operation in the pulverizing step, the solder is hardly pulverized and can be obtained as a relatively large pulverized product while being integrated with the copper foil.

In this embodiment, in order to improve the adhesion between the solder and the copper foil in a processing time of about several hours or less,
A carbonization temperature of at least ℃ is required. On the other hand, the substrate resin component becomes brittle in the dry distillation operation at 250 ° C. or more, and is easily pulverized in the pulverizing step. In this way, components obtained as large crushed products, metal components such as copper foil and solder, and finely divided substrate resin components can be easily separated by the separation operation in the separation process, and the solder is integrated with the copper foil. Therefore, the amount mixed into the substrate resin component is suppressed because it is recovered as a metal component.

Usually, the weakened resin is easily reduced to 100 μm.
m can be crushed. For this reason, especially in the pulverization in the pulverization step, the separation operation in the separation step can be further easily performed by preventing the solder particle diameter from being finely cut to less than 100 μm.

In the present embodiment, electronic components are mounted on a printed circuit board using an epoxy resin, phenol resin, polyester, polyimide, or the like as a substrate resin component, and using paper, glass cloth, glass nonwoven fabric, aramid fiber nonwoven fabric, or the like as a base material. Is a printed circuit board mounted with solder. In particular, when the printed circuit board is one using paper or aramid resin fiber as the base material, the base material is thermally decomposed and embrittled by the dry distillation operation in the heating step, so that the pulverization operation in the pulverization step is easily performed, which is preferable. . Although the Sn / Pb alloy is commonly used as the solder, the present invention can be applied to what is called lead-free solder.

In the heating step of the present invention, the higher the carbonization temperature, the easier copper is to dissolve in the solder, the better the adhesion between the solder and the copper foil, and the shorter the processing time in the heating step.

Heating methods for carbonization include an electric furnace type, an infrared heater type, a far infrared heater type, an induction heating type,
A general heating method such as a hot air method can be applied. The dry distillation atmosphere is preferably performed in a vacuum state or an oxygen-deficient atmosphere in order not to burn the resin component of the substrate and to suppress oxidation of metal components. The oxygen-poor atmosphere is a gas atmosphere having an oxygen concentration of, for example, 10% or lower, and corresponds to an inert gas atmosphere or the like. Examples of the inert gas include rare gases such as helium and argon, nitrogen, and carbon dioxide. Considering handling, it is desirable to use nitrogen gas as the inert gas.

In general, oxidation of a metal component can be suppressed by performing dry distillation in such an atmosphere. However, when a metal is oxidized by a thermal decomposition product of a substrate resin component, the atmosphere gas further contains hydrogen or the like. Oxidation can be suppressed by including a reducing gas.

Further, when the waste printed circuit board contains a flame retardant, the components of the printed circuit board hardly burn even in an air atmosphere, so that the heating step can be performed in an air atmosphere.

In the pulverizing step of the present embodiment, the resin component of the substrate is embrittled by the dry distillation operation in the heating step. Is crushed. In the pulverization operation, it is necessary to set pulverization conditions so that the solder surface is not worn during the pulverization.

For example, jaw crushers, jaw rate crushers generally used as crushers,
Examples thereof include a cone crusher, a roll crusher, an impact crusher, a hammer crusher, and the like, a natural crushing mill, a ball mill, a vibration mill, and a roller mill used as a fine crusher.

Also, a method of blowing a high-pressure gas such as air onto the substrate, a method of crushing by applying vibration to the substrate, and the like are suitable for this embodiment because the solder surface does not wear out. In particular, the ball mill method is preferable because the device configuration is relatively simple and the substrate resin component can be pulverized in a short time. In order to suppress the abrasion of the solder surface by the ball, particles having a surface having a hardness lower than that of the solder are pulverized. It is particularly preferred to use it as a medium.

In this case, the hardness of the surface of the pulverizing medium can be based on Vickers hardness, and a resin material or a rubber material having a lower hardness than solder is used for the surface. In addition, in order to facilitate handling in the pulverizing step, it is also effective to pulverize the printed board previously carbonized by a crushing machine in a short time to about several cm, and then further pulverize the resin substrate portion.

In the separation step in this embodiment, the substrate resin component is pulverized into a fine powder in the pulverization step.
On the other hand, the metal component containing solder is not finely pulverized and has a large particle size, so that it can be efficiently separated by a normal sieving operation. Also, specific gravity separation such as centrifugal classification, inertial classification, and gravity classification can efficiently separate metal components and substrate resin components.

In the present invention, in addition to the above-mentioned heating step, pulverizing step and separating step, another step can be provided if necessary. For example, before the heating step, a step of cutting a leg of the electronic component so that a blade passes between the substrate and the electronic component and previously removing a part of the electronic component from the substrate,
A step of removing a part of the electronic component by removing the solder with a brush or the like while heating and melting the solder and further applying vibration to the printed circuit board can be provided.

[0030]

EXAMPLE A printed circuit board on which electronic components were mounted by soldering on a paper phenol board on which a copper foil pattern was formed was used. The weight of the soldered at this time was measured in advance. The printed circuit board on which the electronic components are mounted is placed in a ceramic furnace core tube having a diameter of 90 mm and a length of 1000 mm, and is heated by an external heating method to reach a predetermined dry distillation temperature, and the temperature is maintained for 120 minutes. , And the printed circuit board was taken out and subjected to a heating step. The heating step was performed by flowing nitrogen at a flow rate of 3 L per minute into the furnace.

Next, as a pulverizing step, the substrate was pulverized to some extent by allowing the substrate to freely fall, and then ball mill pulverization was performed for 30 minutes using a ball having a diameter of 10 mm as a pulverizing medium.

Further, the opening is 500 μm as a separation step.
The crushed material obtained in the crushing step is sieved with a mouth sieve,
It was separated into a substrate resin component collected under the sieve, and an electronic component and a metal component collected as a sieve. In order to quantify the amount of the solder mixed in the obtained substrate resin component, the solder was eluted with acid and subjected to ICP emission analysis, and the ratio to the amount soldered in advance was evaluated as the solder mixing ratio.

Examples 1, 2, 3 and Comparative Example 1 were carried out by setting the carbonization temperature as shown in Table 1. In Examples 1 and 2, balls having a nylon resin surface and a steel core were used, whereas in Example 3, alumina balls were used.

[0034]

[Table 1] In Examples 1, 2, and 3 in which the carbonization temperature is sufficiently high, the heating step causes the copper and the solder to be sufficiently fused to reduce the swelling portion of the solder, and then the substrate resin component obtained by the separation step The mixing ratio of the solder inside was low. On the other hand, in Comparative Example 1, since the dry distillation temperature in the heating step was insufficient, the brittleness of the substrate resin component was insufficient, and the substrate could not be pulverized in the pulverization step. The metal material could not be separated.

Further, in Example 3, since the grinding medium having a surface hardness higher than that of the solder was used as the grinding medium, the solder surface was abraded and the solder mixing ratio was increased as compared with Example 1.

(2) A method for separating a metal material from a waste printed circuit board according to a second embodiment of the present invention will be described below with reference to the drawings.

In the present embodiment described below, a waste printed board is a copper-clad laminate in which copper foil is stacked on a board, a printed wiring board in which wiring is provided on a board, and electronic components are mounted on a board. A printed circuit board on which a mounted circuit is formed, or a printed circuit board in which all or some of the electronic components have been removed from the printed circuit board in advance, and are generated in a waste printed board generated from a used product or in a manufacturing process. Defective products and scraps. In addition, the substrate part of the waste printed circuit board contains a substrate resin component such as epoxy resin, phenol resin, polyester, and polyimide, and paper, glass cloth, glass fiber nonwoven fabric, aramid fiber nonwoven fabric, etc. are used as a base material. It is.

FIG. 2 shows a flow of a method for separating a waste printed circuit board from a metal material according to the second embodiment of the present invention.

As shown in FIG. 2, in the method for separating a metal material from a waste printed circuit board according to the present embodiment, a heating step is performed first, a cooling step is performed, a pulverizing step is performed, and then a separating step is performed. Board resin component, copper foil, solder,
It is separated into metallic materials such as electronic components. Strictly speaking, electronic components often include a resin component, but in the present embodiment, an electronic component including such a resin component is also treated as a metal material.

Hereinafter, the heating step, the cooling step, the pulverizing step, and the separating step will be described.

First, the heating step will be described. The heating step includes, using an electric furnace, an infrared heater, a far-infrared heater, induction heating, hot air, etc., the waste printed circuit board having a metal material such as solder and electronic components, and the temperature of the printed circuit board portion of the waste printed circuit board. Is a step of heating so as to be 250 ° C. or more and less than 500 ° C. This heating process embrittles the printed board resin component constituting the waste printed board.

The heating step is desirably performed in an oxygen-deficient atmosphere in order not to burn the resin component of the printed circuit board and to suppress oxidation of the metal material. The oxygen-deficient atmosphere means a gas atmosphere in which the oxygen concentration is, for example, 10% or lower, and in which the printed board resin component does not burn or the metal material does not oxidize. And so on. Examples of the inert gas include rare gases such as helium and argon, nitrogen, and carbon dioxide. Considering handling, it is preferable to use nitrogen as the inert gas. The oxygen-deficient atmosphere also includes a state in which the atmospheric gas is reduced in pressure or evacuated. Also, when the metal material is oxidized by the thermal decomposition gas of the substrate resin component,
Further, a reducing gas such as hydrogen may be contained. Oxidation of the metal material can be suppressed by the reducing gas.

Further, when the waste printed board contains a flame retardant, the printed board resin component hardly burns even in an air atmosphere, so that the heating step can be performed in an air atmosphere.

In the above-mentioned heating step, the printed circuit board is heated so that the temperature of the printed circuit board becomes 250 ° C. or more. However, when the heating temperature becomes 250 ° C. or more, the decomposition reaction of the resin component of the board starts to progress, and the board becomes brittle. Because it starts. The embrittlement of the substrate progresses with an increase in the heating temperature, but at the same time, the amount of the resin component, which is the substrate resin component due to the heat treatment, and the amount of decomposition products of additives such as the flame retardant contained in the waste printed circuit board increase, resulting in the heating process There is a concern about the environmental load on the surroundings due to exhaust gas. In view of the behavior of the decomposition products generated in the heating process, the effect of the heating temperature on the environmental load was examined in detail.As a result, if the waste printed circuit board contained a halogen compound such as organic bromide as a flame retardant, When the temperature is 500 ° C. or higher, the amount of hydrogen halide, which is a decomposition gas, is significantly increased, and the lead halide generated by the reaction between the hydrogen halide and lead in the solder starts to scatter in the exhaust gas. Need to be performed at less than 500 ° C. When the heating temperature is 50
When the temperature is 0 ° C. or higher, a side reaction between the hydrogen halide and a metal material such as a copper foil is likely to occur, and the heating temperature needs to be lower than 500 ° C. from the viewpoint of lowering the quality of the recovered metal material. Therefore, in the heating step, the temperature of the printed circuit board portion is set to be 250 ° C. or more and 500 ° C.
Heat the waste printed circuit board.

It should be noted that when the waste printed circuit board is heated in the range of 350 ° C. to less than 500 ° C., the embrittlement of the board can be completed in a shorter time than when the heating temperature is 250 ° C. or more and less than 350 ° C. Can be.

Next, the cooling step will be described. The cooling step is a step of cooling the waste printed circuit board heated in the heating step. If the waste printed circuit board in a high temperature state is directly exposed to the air in the heating step, the printed circuit board portion may burn, and the metal material is oxidized. Therefore, in order to prevent the burning of the printed circuit board portion and the oxidation of the metal material, the waste printed circuit board heated in the heating step is cooled in an oxygen-deficient atmosphere. The low oxygen atmosphere is as described above. As the cooling method, a method of spontaneously cooling under a low oxygen atmosphere, a method of blowing an inert gas such as a nitrogen gas near room temperature to a heated waste printed circuit board is used. Etc. can be used. In addition,
In order to prevent the printed circuit board portion from burning, the waste printed circuit board must be cooled to a temperature at which the printed circuit board portion does not burn, for example, 180 ° C. or less.

Next, the pulverizing step will be described. The pulverizing step is a step of finely pulverizing the embrittled substrate resin component of the waste printed circuit board cooled in the cooling step. When the substrate resin component is pulverized, it is necessary to suppress the pulverization of metal materials such as copper foil, solder, and electronic components as much as possible in order to easily separate the substrate resin component from the metal material. . Therefore, in the pulverizing step in the present embodiment, a pulverizing method with a small pulverizing force is used to suppress pulverization of the metal material and finely pulverize the resin component of the substrate. As a specific pulverizing method, a particle collision operation in which a large number of particles collide with a waste printed board that has passed through a heating process,
Alternatively, a method of performing a wall collision operation of colliding a waste printed circuit board with a wall surface is used. This is because, in both the particle collision operation and the wall collision operation, the impact force at the time of one collision is small, so that the crushing of metal materials such as electronic components is suppressed. This is because fine powdering can be suppressed even with a copper foil that is easily cut. Normally, a waste printed circuit board that has not undergone a heating step cannot be crushed by a particle collision operation or a wall collision operation. By the collision operation, the substrate resin component can be substantially selectively pulverized. On the other hand, when crushing a waste printed board that has undergone a heating step using a crusher that rotates a cutting blade or a crusher that rotates a hammer (a hammer mill) that is commonly used in conventional waste treatment, Since the crushing force is too strong, metal materials such as electronic components, copper foil, and solder are also finely cut, which makes it difficult to separate and collect the subsequent metal material, which is not suitable for the crushing step of the present invention.

Next, a specific example of the above-described particle collision operation will be described. As a specific example, as shown in FIG.
There is a rolling ball mill system in which a large number of particles 2 and a heated waste printed circuit board 3 are sealed in a container 1, and the container 1 is rotated in the direction of arrow 4 to crush the particles 2 by free fall. As another specific example of the particle collision operation, as shown in FIG. 4, a large number of particles 2 and a heated waste printed circuit board 3 are sealed in a container 1, and the container 1 is vibrated up and down in the direction of arrow 4. There is a vibrating ball mill system in which the particles 2 are crushed by vibrating motion. Although FIG. 4 shows the pulverization by the vertical movement, the pulverization can also be performed by the left and right movement, the rotation movement, or a combination of these movements. Further, as another specific example of the particle collision operation, as shown in FIG. 5, an injection unit 5 capable of injecting the particles 2 at high speed by using compressed air or the like is prepared.
There is a method in which a large number of particles 2 are sprayed onto a heated waste printed circuit board 3 so that the large number of particles 2 collide with the waste printed circuit board 3 and are crushed. Among these specific examples, in particular, the use of a vibration ball mill system and a system in which particles are ejected allows the particles to move at a high speed to pulverize the waste printed circuit board, so that the pulverization process can be completed in a short time. preferable.

The particles used in the above-described particle collision operation are particles made of a ceramic material such as alumina or zirconia, a metal material such as iron or stainless steel, or a synthetic resin material. If particles having a large specific gravity, such as ceramics and metals, are used, the crushing power is relatively large and the crushing speed is high. On the other hand, when a material having a small surface hardness such as a synthetic resin is used, abrasion of the metal material of the waste printed circuit board can be suppressed. Therefore, particles made of a ceramic or metal material as a core material and having a surface made of a synthetic resin satisfy both conditions and are preferable. If the size of the particles is too small, the crushing power is reduced and the crushing speed is reduced, and further, since the curvature of the particles at the crushing point is small, the thickness is small and the thickness is small. Particles having a diameter of 1 mm or more, preferably 10 mm or more are used. Furthermore, when the particle size is 2
When particles having a diameter of 0 mm or more are used, many of the electronic components are smaller than the particles. Therefore, the particles and the electronic components can be easily and efficiently separated by sieving in a separation step described below, which is preferable. The shape of the particles is not particularly limited, but the use of particles having corners promotes fine powdering of the copper foil.

In the above-described particle collision operation, since the crushing point per particle is small, it can be easily crushed even in a place where the electronic component becomes an obstacle and the substrate component is hardly crushed, such as near the lead wire of the electronic component. There is.

In the above-described particle collision operation, a large number of particles 2 are used to pulverize the resin component of the waste printed circuit board 3, but one or several particles 2 are used to pulverize the substrate of the waste printed circuit board 3. The resin component may be ground.

Next, a specific example of the above-described wall collision operation will be described. As a specific example, as shown in FIG. 6, a cylindrical container 1 in which a plurality of scooping plates 6 are arranged on an inner wall in an axial direction.
Is prepared, the container 1 is tilted, the heated waste printed circuit board 3 is charged into the container 1, the container 1 is rotated in the direction of arrow 4, and the waste printed circuit board 3 is scooped up by the scooping plate 6, In this case, the waste printed circuit board 3 is caused to collide with the inner wall of the container 1 and / or the scooping plate 6 to substantially crush the printed circuit board portion of the waste printed circuit board 3. The use of this method is preferable in that the waste printed circuit board 3 can be reliably scooped up to the upper portion of the container 1 without slipping in the rotating container 1 and can be dropped and crushed. In addition, the configuration shown in FIG. 6 is preferable in terms of operation because the crushed fragments of the waste printed circuit board 3 and the metal material are continuously discharged from the discharge port of the container 1. As another specific example of the wall collision operation, as shown in FIG. 7, a heated waste printed circuit board 3 is thrown toward a wall surface 8 using a rotating tray 7 or the like, and the waste printed circuit board 3 is placed on the wall surface 8. Collision may substantially crush the printed circuit board portion of the waste printed circuit board 3. In this method, the grinding speed can be increased by forcibly causing the waste printed circuit board 3 to collide with the wall surface 8.

Such a wall collision operation can be performed with a simple apparatus configuration. In particular, unlike the above-described particle collision operation, there is no need to perform an operation of separating metal materials such as collected electronic components from particles. There is a feature that there is.

The scooping plate 6 shown in FIG. 6 was used as a rib disposed on the inner wall of the cylindrical container used in the pulverizing step according to the present invention. Further, in FIG. 6 described above, the plurality of scooping plates 6 are arranged on the inner wall of the cylindrical container 1,
It is only necessary that at least one scooping plate 6 is arranged on the inner wall of the container 1.

Next, the separation step will be described. The separation step is a step of separating fine powdery fragments of the substrate resin component pulverized in the above-described pulverization step from a metal material that is not substantially pulverized. In the pulverizing step, the substrate resin component is substantially pulverized into fine powder-like fragments, but the metal material is not substantially pulverized and remains as it is and has a large particle size. Because they are so different
It can be separated efficiently by a sieving operation. When a sieving operation is used, the metal material is usually 100 to 1000
The resin component collected on the upper side of the sieve having an opening of μm is collected on the lower side of the sieve having an opening of about 100 to 500 μm. In addition, even if a specific gravity separation method such as centrifugal classification, inertial classification, or gravity classification is used, the metal material and the substrate resin component can be efficiently separated. When a small piece of a metal material is included in the separated substrate resin component, the recovery rate of the metal material is improved by further performing a separation operation such as specific gravity separation. Further, when a relatively large substrate in which the pulverization of the substrate resin component is insufficient after the pulverization step is included, it is possible to select by sieving in the separation step, return to the pulverization step, and pulverize again. .

As described above, the metal material such as copper foil, solder, and electronic parts can be easily separated in the separation step. Therefore, if the separated metal material is recovered, it can be used as a resource material. In addition, the waste printed circuit board can be rendered harmless.

Next, a metal material recovery step of separately recovering the metal materials separated in the separation step according to the shape is performed. As shown in FIG. 8, a belt conveyor 9 is prepared in which the belt is inclined at a predetermined angle with respect to the horizontal plane and the belt advances from the lower side to the upper side, and the metal material separated in the separation step is placed on the belt conveyor 9. Then, the cylindrical metal material and the hard-to-fall metal material are separately collected. Specifically, if the metal material to be supplied to the belt conveyor 9 is a metal material having an easy-to-fall shape such as a columnar electronic component such as an aluminum electrolytic capacitor and a linear electronic component such as a resistor, the metal Since the material easily falls on the belt conveyor 9,
It can be recovered by the easily fallable metal material recovery unit 10 located on the lower side. On the other hand, if the metal material is a flat electronic component such as an integrated circuit component or a metal material having a foil-like hard-to-fall shape such as copper foil, the metal material does not easily fall on the belt conveyor 9, It can be collected by the hard-to-fall metal material recovery unit 11 located on the upper side. At this time, the separation speed can be further increased by applying vibration to the belt.

As described above, the metal material can be further separated and recovered according to its shape because the substrate is embrittled by the above-mentioned heating step, and the substrate is pulverized with a small pulverizing force in the pulverizing step, so that electronic components and the like can be obtained. This is because the metal material can be kept close to the original shape.

According to the second embodiment of the present invention, there is provided a method for separating a metal material from a waste printed circuit board, which includes a heating step, a cooling step, a pulverizing step, a separating step, and a metal material collecting step. Can be provided. For example, before the heating step, a step of removing relatively large electronic components, electronic components or lead wires that may generate harmful substances in the heating step, can be provided in advance. Before the heating step, the waste printed circuit board is
When the immersion treatment step of immersing in a decomposition solution containing at least one of propylene glycol, diethylene glycol, dipropylene glycol, isopropylene glycol, and sodium hydroxide solution is performed, a part of the substrate resin component is decomposed in advance by the decomposition solution. Alternatively, swelling is possible, and the substrate resin component can be sufficiently embrittled in a short time even at a low heating temperature in the heating step, which is preferable. The immersion treatment step is preferably performed at a high temperature, since a part of the substrate resin component promotes decomposition or swelling, and is performed at a temperature in the range of 50 to 300 ° C.

In the above-described embodiment, the cooling step is performed after the heating step, and the pulverizing step is performed after that. However, when the waste printed circuit board does not contain solder, the solder is melted. Since there is no need to consider the scattering of solder, the pulverizing step may be performed at the same time as the heating step. Alternatively, the pulverizing step may be performed at a high temperature without cooling the waste printed circuit board after the heating step. Similarly, the separation step may be performed without cooling the waste printed circuit board. In this case, the pulverizing step and / or the separating step may be performed in the above-described oxygen-deficient atmosphere in order to prevent the burning of the resin component of the printed board and the oxidation of the metal material. In that case,
After the pulverization step or the separation step, the printed board resin component and the metal material in a high temperature state are brought to a low temperature state, and then a metal material recovery step is performed. As a method for bringing the printed board resin component and the metal material in a high temperature state to a low temperature state, in order to prevent the burning of the printed board resin component and the oxidation of the metal material, natural cooling is performed under the above-described oxygen-deficient atmosphere. Or a method in which an inert gas such as a nitrogen gas at around room temperature is sprayed on the printed board resin component or the metal material.

On the other hand, when a waste board is subjected to a heating step while maintaining the shape of the printed board containing a halogen component such as chlorine or bromine and an antimony component as a flame retardant, the separation step is performed. Halogen components and antimony components may remain on the collected fragments of the printed circuit board.

Assuming a case where the printed circuit board portion is recycled and then discarded again, the halogen component and the antimony component may become environmentally harmful substances depending on the disposal method. It is desired to remove the fuel component.

Therefore, in the present invention, the fragments of the printed circuit board portion separated by the heating step, the pulverizing step, and the separating step are brought into an atmosphere in which the fragments are not burned out at least at a temperature of 350 ° C. or more. It is preferable to include a heat removal step of heating the flame retardant from the shards to remove the flame retardant.

A flame retardant containing a halogen component or an antimony component is thermally decomposed at around 250 ° C. in order to exhibit a flame-retardant effect. Therefore, in the heating step in the present invention, the halogen component and the antimony component are released from the substrate. But,
When the heating process is performed on the waste printed circuit board while maintaining the board shape, the surface area is not large, and the waste printed circuit board is made of thermosetting resin such as phenol resin or epoxy resin, and the board part melts during the thermal decomposition process Therefore, the halogen component and the antimony component in the substrate are not easily removed from the substrate by heating.

Therefore, in the present invention, since the fragments of the printed circuit board portion separated in the separation step having a large surface area are heated, the halogen component and the antimony component can be easily volatilized from the substrate portion. .

In the heat removal step in the present invention, the heating temperature must be 350 ° C. or higher in order to easily remove the halogen component and the antimony component. It is necessary to perform the heating in an atmosphere in which the fragments do not burn out. It is desirable to carry out the treatment in an oxygen-deficient atmosphere,
When performed at 0 ° C. or lower, it is also possible to perform in air.

On the other hand, the lead component, which is an environmentally hazardous substance in the waste printed circuit board, is mainly contained not only as a plating for a lead portion of an electronic component or as a solder for mounting the electronic component, but also as a coating resin for a lead wire or a component. In some cases, stabilizers of polyvinyl chloride used as a base are contained as basic carbonates, tribasic sulfates, lead stearate and the like.

In the present invention, the lead component contained in the plating of the lead portion of the electronic component and the solder for mounting the electronic component is not crushed finely, so that the lead component is easily converted into a metal material component from the fragments of the printed circuit board. It can be separated and collected. However, since the lead component existing as a stabilizer of polyvinyl chloride is originally finely dispersed in the resin, when the present invention is applied, the lead component is a small component in the printed circuit board portion. Mixed with the debris components.

The printed board portion contains an antimony component as a flame retardant component. Since this antimony component is also finely dispersed in the printed circuit board portion, when the present invention is applied, the antimony component is mixed with the small component of the printed circuit board portion which is a small component.

In consideration of the recycling of the debris components of the printed circuit board, it is desirable to remove such a mixed lead component and antimony component which are environmentally harmful substances. It is preferable to perform an elution removal step of bringing the separated pieces of the waste printed circuit board portion into contact with water to elute and remove heavy metals from the pieces of the waste printed circuit board.

The lead component, which was mainly present as a stabilizer for polyvinyl chloride, reacts with hydrogen chloride generated when polyvinyl chloride is thermally decomposed in the dry distillation step to form lead chloride.

When a brominated flame retardant is contained in a printed circuit board, it is thermally decomposed during the carbonization step to generate bromine gas and hydrogen bromide. It may be formed. In other words, in the carbonization process, the lead component reacts with the halogen gas or hydrogen halide gas generated by thermal decomposition to form lead halide, and this lead halide is mixed into the fragments of the printed circuit board portion recovered in the separation process. I do.

Since this lead halide is easily dissolved in water, the lead component can be easily eluted and removed from the waste printed circuit board fragments by performing an elution step of bringing separated pieces of the printed circuit board into contact with water. Similarly, in the case of antimony, in the dry distillation step, halogen gas or hydrogen halide generated by thermal decomposition reacts with the antimony component to form antimony halide, and the printed circuit board portion where the antimony halide is recovered in the separation step Mixed into the fragments.

Since the antimony halide is also easily dissolved in water, the elution step is performed using the water of the present invention.
Antimony components can be easily eluted and removed from the pieces of the printed circuit board separated in the separation step.

In the elution removal step of the present invention, additional components may be appropriately added to water. As the operation method,
A method of immersing the separated printed circuit board portion in water or spraying water on the separated printed circuit board portion is used.

[0076]

Hereinafter, the present invention will be described in more detail with reference to specific examples.

Example 1 An integrated circuit component, an aluminum electrolytic capacitor, a fixed resistor, a connector, and the like are mainly mounted on a composite substrate made of glass fiber nonwoven fabric / glass cloth and epoxy resin and containing a brominated flame retardant. A waste printed circuit board (size: 50 mm × 150 mm) is placed in a ceramic furnace core tube having a diameter of 90 mm and a length of 1000 mm, and heated from outside the furnace core tube to reduce the waste printed circuit board to 250 mm.
The substrate temperature was maintained for 120 minutes after the temperature was raised to ° C., and then the substrate was allowed to cool until the substrate temperature reached 40 ° C., and the waste printed circuit board was taken out to perform a heating step and a cooling step. The heating step and the cooling step were performed by flowing nitrogen at a flow rate of 3 L per minute into the furnace. In the pulverizing step, a vibrating ball mill method is adopted, and a device (a paint shaker, manufactured by Asada Iron Works Co., Ltd.) vibrating 640 times per minute with an amplitude of 8 mm is used to place the inside of a stainless steel cylindrical container having an inner diameter of 130 mm and a depth of 180 mm. This was carried out by enclosing iron particles having a particle diameter of 20 mm whose surface was coated with a nylon resin and a waste printed circuit board that had undergone a heating step. The obtained pulverized material was passed through a sieve having a mesh size of 200 μm to perform a separation step, and was separated into a substrate resin component collected below the sieve and electronic components and metal materials collected above the sieve. .

The heating was performed at 350 ° C. and 450 ° C. in exactly the same manner. Further, as a comparative example, when the heating step and the cooling step were not performed, when the heating temperature was set to 200 ° C., and when the heating temperature was set to 500 ° C., the treatment was performed by the same operation. Table 2 shows the results. The time required for the substrate to be substantially completely pulverized was measured as the time required for the pulverization. Further, lead in the exhaust gas was detected in order to confirm the scattering of lead from the solder into the exhaust gas in the heating step.

[0079]

[Table 2] As is clear from Table 2, the waste printed circuit board was heated at a heating temperature of 2.
When the treatment was performed at 50 ° C. or more and less than 500 ° C., the lead could be separated into the substrate resin component and the metal material (electronic parts, copper foil, solder) without scattering in the exhaust gas.
In particular, by setting the heating temperature to 350 ° C. or more and less than 500 ° C., the time required for pulverization could be reduced. On the other hand, when heating is not performed as in the comparative example, or when the heating temperature is set to 200 ° C.,
The substrate could not be ground because it was not embrittled. When the heating temperature was set to 500 ° C., scattering of lead in the exhaust gas was confirmed.

Example 2 Using the same waste printed circuit board as in Example 1, the heating temperature and the heating temperature were set to 350 ° C., and the heating step and the cooling step were performed in the same manner as in Example 1. As a crushing process,
Particle size 2 using an injection processing machine (Fuji Manufacturing Co., Ltd.)
mm nylon resin particles were sprayed onto a waste printed circuit board having undergone a cooling step at a spray pressure of 0.5 MPa. The obtained pulverized material is passed through a sieve having an opening of 200 μm to perform a separation step, and a substrate resin component collected on the lower side of the sieve,
It was separated into electronic components and metal materials collected on the upper side of the sieve.

As a result, in the pulverizing step, the substrate was substantially pulverized in about 5 minutes, and in the subsequent separating step, the resin component of the substrate and the metal material (electronic parts, copper foil, solder) could be separated.

(Embodiment 3) Electronic components on which an integrated circuit component, an aluminum electrolytic capacitor, a fixed resistor and the like are mainly mounted are mounted on a paper phenol substrate made of kraft paper and phenol resin and containing a brominated flame retardant. The waste printed board (size 50 mm × 150 mm) was heated and cooled at 350 ° C. in the same manner as in Example 1. As the pulverizing step, a wall collision operation in which the waste printed circuit board subjected to the heating step was put into a predetermined bag and thrown onto the floor 50 times was used. The obtained pulverized material has an opening of 500 μm.
m, a separation process was performed to separate the substrate resin component collected below the sieve from the electronic components and metal materials collected above the sieve. In addition, the inclination angle is 20 degrees,
The metal material recovery step was performed by supplying the recovered metal material onto a belt of a belt conveyor running from the lower side to the upper side at a belt speed of 150 mm / sec.

The result is that the substrate is substantially completely pulverized in the pulverizing step, and the resin component of the substrate and the metal material can be separated in the subsequent separating step. It could be separated into groups such as resistors, and groups consisting of integrated circuits and copper foil.

Example 4 A waste printed circuit board (size: 50 mm × 150 mm), which is a printed circuit board made of kraft paper and a phenolic resin and containing only wiring on a paper phenolic board containing a brominated flame retardant, was heated at a heating temperature. 350
The heating step and the cooling step were performed in the same manner as in Example 1 at a temperature of ° C. In the pulverization step, only the waste printed circuit board after the cooling step is put into a cylindrical container having an inner diameter of 300 mm and a depth of 500 mm having a scooping plate on the inner wall surface at an interval of 45 °, and is charged for 5 minutes per minute.
A wall collision operation was performed to make a rotation of 00. The obtained pulverized material is passed through a sieve having an opening of 500 μm to perform a separation step, and is separated into a substrate resin component collected below the sieve and a metal material made of copper foil collected above the sieve. did.

As a result, in the pulverizing step, the substrate was substantially pulverized in about 10 minutes, and in the subsequent separating step, the substrate resin component and the metal material (copper foil) could be separated.

Example 5 The same waste printed circuit board as in Example 1 was immersed in ethylene glycol at 170 ° C. for 2 hours to perform an immersion process. Thereafter, the heating step and the cooling step were performed in the same manner as in Example 1 except that the heating temperature was set to 250 ° C. In the pulverizing step, a vibration ball mill method was used under the same conditions as in Example 1. The obtained pulverized material has an opening of 2
The resin was passed through a sieve having a size of 00 μm to perform a separation step, and was separated into a substrate resin component collected below the sieve and electronic components and metal materials collected above the sieve.

When the heating temperature was set to 250 ° C. in Example 1, it took 30 minutes for the pulverization in the pulverization step. On the other hand, the dipping treatment step in this example was performed before the heating step to reduce the pulverization. The required time can be shortened to 10 minutes, and the substrate resin component and the metal material (electronic parts, copper foil, solder) can be separated.

Example 6 The substrate resin component recovered below the sieve in Example 3 was 90 mm in diameter.
Using a ceramic furnace core tube having a length of 1000 mm, nitrogen was flowed at a flow rate of 3 L per minute into the furnace at 350 ° C. for 12 minutes.
After maintaining the temperature for 0 minutes, the temperature was lowered to 40 ° C., and the substrate resin component was taken out of the furnace core tube.

When the bromine content in the substrate resin component before and after the heat removal step was measured, the bromine content was 5.5% by weight before the heat removal step, but was 0.1% by weight after the heat removal step. %.

Example 7 An integrated circuit component, an aluminum electrolytic capacitor, a fixed resistor, and the like were mainly mounted on a paper phenol substrate made of kraft paper and a phenol resin and containing a brominated flame retardant, and further included a lead wire. Heat the waste printed circuit board (size 50 mm x 150 mm)
At 50 ° C., a heating step, a cooling step, a pulverizing step, and a separating step were performed in the same manner as in Example 1 to obtain a substrate resin component collected below the sieve. 10 of the obtained substrate resin component weight
Mix the substrate resin component with double weight water and stir while stirring.
The elution removal step was performed by immersing for an hour. Thereafter, the substrate resin component was recovered by filtration and dried.

The lead component in the substrate resin component before and after the elution removal step was eluted with acid and the lead content in the substrate resin component was measured by ICP emission analysis. The content was 0.2% by weight,
By performing the elution removal step, the concentration was reduced to 0.0003% by weight.

(Comparative Example 1) The same waste printed board as in Example 1 was heated and cooled at 350 ° C. under the same conditions as in Example 1. Crushing step 280
The test was performed using a hammer mill (H-12 type, manufactured by Hosokawa Micron Corporation) that pulverizes with a hammer rotating at 0 rotation / minute. The obtained pulverized material is passed through a sieve having an opening of 200 μm to perform a separation step, and is separated into a substrate resin component collected below the sieve and electronic components and metal materials collected above the sieve. Tried that.

As a result, in the pulverizing step, the electronic components were also finely pulverized, and in the recovered material below the sieve, many metal pieces such as copper foil and electronic component leads were mixed in the substrate resin component. Could not be separated efficiently.

[0094]

As is apparent from the above description, the method for treating a waste printed circuit board according to the first aspect of the present invention provides:
The amount of residual solder in the obtained substrate resin component can be suppressed, and the metal component and the substrate resin component can be efficiently separated.

The second aspect of the present invention can provide a method for separating a metal material from a waste printed board, which efficiently separates the metal material from the waste printed board.

[Brief description of the drawings]

FIG. 1 is a view showing a processing apparatus for carrying out an embodiment of a method for processing a waste printed circuit board according to the first invention;

FIG. 2 is a diagram showing a flow of a method of separating a waste printed circuit board from a metal material according to the second embodiment of the present invention;

FIG. 3 is a diagram for explaining a particle collision operation in a pulverizing step of the method for separating a waste printed circuit board from a metal material according to the second embodiment of the present invention;

FIG. 4 is a view different from FIG. 3 for explaining a particle collision operation in a pulverizing step of the waste printed circuit board metal material separating method according to the second embodiment of the present invention;

FIG. 5 is a diagram different from FIG. 3 or FIG. 4, for explaining a particle collision operation in a pulverizing step of a method of separating a waste printed circuit board from a metal material according to the second embodiment of the present invention;

FIG. 6 is a view for explaining a wall collision operation in a pulverizing step of a method for separating a waste printed circuit board from a metal material according to the second embodiment of the present invention;

FIG. 7 is a view different from FIG. 6 for explaining a wall collision operation in a pulverizing step of the waste printed circuit board metal material separating method according to the second embodiment of the present invention;

FIG. 8 is a view for explaining a metal material recovery step of the method for separating a metal material from a waste printed circuit board according to the second embodiment of the present invention;

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Container 2 Particles 3 Waste printed circuit board 4 Arrow indicating direction of movement of container 5 Injecting means 6 Scooping plate 7 Rotating tray 8 Wall surface 9 Belt conveyor 10 Easy falling metal material collecting section 11 Hard falling metal material collecting section 12 Heating process 13 Crushing process 14 Separation process

Continuing on the front page (72) Inventor Masaaki Suzuki 1006 Kazuma Kadoma, Osaka Pref.Matsushita Electric Industrial Co., Ltd. Person Takahiko Terada 1006 Kazuma Kadoma, Kadoma City, Osaka Prefecture F-term (reference) 4D004 AA24 AB03 BA05 CA04 CA08 CA12 CA24 CA32 CA34 CA40 CA41 CB13 CC04 CC12 DA03 DA06 DA20 4K001 AA09 AA20 AA24 BA22 CA06 CA05 CA05

Claims (16)

[Claims] 1. A heating step of carbonizing a printed circuit board having a copper foil on which solder is disposed on at least a part of its surface at a temperature of 250 ° C. or more, and pulverizing the carbonized product of the printed circuit board obtained in the heating step. And a separation step of separating the crushed waste printed board obtained in the crushing step into a substrate resin component and a metal component. 2. The method according to claim 1, wherein the crushing in the crushing step is performed so that the particle size of the solder is not finely cut to less than 100 μm. 3. The waste printed circuit board according to claim 1, wherein the pulverization in the pulverization step is performed by ball mill pulverization using a pulverization medium having a surface lower in hardness than solder. Processing method. 4. A method of manufacturing a waste printed circuit board having at least a metal material under an atmosphere in which the printed circuit board portion of the waste printed circuit board does not burn, or in an atmosphere in which the metal material is not oxidized, wherein the temperature of the printed circuit board portion is at least 2.
A heating step of heating so as to be 50 ° C. or more and less than 500 ° C .; a pulverizing step of pulverizing substantially only the printed circuit board portion of the waste printed circuit board heated in the heating step into fragments having a predetermined size or less. Separating the fragments of the substantially printed circuit board portion pulverized in the pulverizing step and the metal material provided on the waste printed circuit board based on a difference between the size of the fragments and the size of the metal material. A method of separating a metal material from a waste printed circuit board. 5. The method according to claim 5, wherein the waste printed circuit board having at least a metal material is heated in an atmosphere in which the printed circuit board portion of the waste printed circuit board does not burn, or in an atmosphere in which the metal material is not oxidized.
A heating step of heating to 50 ° C. or more and less than 500 ° C .; and colliding predetermined particles against the waste printed board heated in the heating step, thereby substantially crushing the printed board portion of the waste printed board. Crushing step, fragments of the substantially printed circuit board portion crushed in the crushing step, and the metal material provided on the waste printed circuit board, the difference between the size of the fragments and the size of the metal material And separating the waste printed circuit board from the metal material. 6. The pulverizing step includes enclosing the heated waste printed circuit board and the particles in a predetermined container, and rotating and / or vibrating the container to cause the particles to collide with the waste printed circuit board. 6. The method according to claim 5, wherein
A method for separating a metal material from a waste printed circuit board according to the above. 7. In the pulverizing step, an injection means capable of injecting the particles at a predetermined speed is provided, and the injection means injects the particles to the heated waste printed circuit board. 6. The method according to claim 5, wherein the step (c) is performed by colliding the waste printed circuit board with the waste printed circuit board. 8. The method according to claim 1, wherein the waste printed circuit board having at least a metal material is heated in an atmosphere in which the printed circuit board portion of the waste printed circuit board does not burn or in an atmosphere in which the metal material is not oxidized.
A heating step of heating to 50 ° C. or more and less than 500 ° C., a cylindrical container having an inner wall provided with a predetermined rib in an axial direction, and the waste printed circuit board heated in the heating step is placed in the container. And the container is rotated, and the waste printed circuit board is caused to collide with the inner wall and / or the rib of the container to pulverize a substantially printed circuit board portion of the waste printed circuit board. A separation step of separating the crushed pieces of the substantially printed circuit board portion and the metal material provided on the waste printed circuit board based on a difference between the size of the pieces and the size of the metal material. A method for separating a metal material from a waste printed circuit board. 9. The method according to claim 9, wherein the waste printed board having at least the metal material is heated in an atmosphere in which the printed board portion of the waste printed board does not burn, or in an atmosphere in which the metal material is not oxidized.
A heating step of heating so as to be 50 ° C. or more and less than 500 ° C .; throwing the waste printed board heated in the heating step to a predetermined object, causing the waste printed board to collide with the object, A pulverizing step of pulverizing a substantially printed circuit board portion of the substrate; a fragment of the substantially printed circuit board portion pulverized in the pulverizing step; and a metal material provided on the waste printed circuit board, and a size of the fragment. A separating step of separating based on a difference in size of the metal material. 10. The metal material for a waste printed circuit board according to claim 4, wherein the heating in the heating step is performed so that the temperature of the at least the printed circuit board portion is 350 ° C. or higher. Separation method. 11. A cooling step of cooling the waste printed board heated in the heating step after the heating step, wherein the pulverizing step substantially prints the waste printed board cooled in the cooling step. The method according to any one of claims 4 to 10, wherein the substrate portion is crushed. 12. The method according to claim 11, wherein the cooling step is performed in an atmosphere in which a printed circuit board portion of the waste printed circuit board does not burn, or in an atmosphere in which a metal material of the waste printed circuit board does not oxidize. A method for separating metal materials from waste printed circuit boards. 13. Prior to performing the heating step, the waste printed circuit board having at least the metal material is subjected to at least one of ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol, isopropylene glycol, and a sodium hydroxide solution.
The method for separating a metal material from a waste printed circuit board according to any one of claims 4 to 12, further comprising an immersion treatment step of immersion in a decomposition solution containing a seed. 14. A belt conveyor that is inclined with respect to a horizontal plane and moves upward from below is provided, and the metal material separated in the separation step is supplied onto the belt conveyor, If the shape is easy to fall, the metal material is collected at the lower part of the belt conveyor, and if the shape of the metal material is hard to fall, the metal material is collected at the upper part of the belt conveyor. 14. The method according to claim 4, further comprising a material recovery step. 15. A fragment of the substantially printed circuit board portion separated in the separating step is heated under an atmosphere in which the fragment is not burned out so that the temperature of the fragment is at least 350 ° C. or more, and 14. The method for treating a waste printed circuit board according to claim 4, further comprising a heat removal step of heating and removing the flame retardant. 16. The method according to claim 4, further comprising an elution removing step of contacting water with the fragments of the substantially printed circuit board part separated in the separation step to elute and remove heavy metals from the fragments. A method for treating a waste printed circuit board according to any one of claims 13 to 13.