JP2019037945A - Method of recovering valuable metal from printed circuit board scrap - Google Patents

Abstract

To provide a method of recovering valuable metal from printed circuit board scrap that can improve the recovery rate of valuable metal from the printed circuit board scrap and its quality.SOLUTION: The method has a first step for crushing printed circuit board scrap with an impact crusher (10A, 10B) by one stage or two stages, a second step for crushing the crushed matter that is obtained by crushing the printed circuit board scrap, with a final crusher (10C), and a third step for separating the powder matter that results from crushing with the final crusher, with a pneumatic separator (70), into powder matter mainly composed of valuable metal, and other parts, to recover the valuable metal from the powder matter. The first, second and third steps are continuously performed.SELECTED DRAWING: Figure 3

Description

  The present invention relates to a method for recovering valuable metals from printed circuit board waste.

  Methods have been proposed for recovering valuable metals such as copper troughs from printed circuit boards, printed circuit boards on which components are mounted, and molding residues generated in these manufacturing processes.

  For example, Patent Document 1 discloses that a processing object is roughly pulverized, and then finely pulverized by applying an external force such as a compressive force or a shearing force. Separation is performed using the specific gravity difference of a part containing a large amount of a material having a small specific gravity such as a resin, and further valuable metal is recovered by electrostatic separation into a part containing a large amount of conductor and a part containing a large amount of an insulator. A method is disclosed.

Japanese Patent Application Laid-Open No. 07-251154

  When recovering valuable metals such as copper trough from a printed circuit board or the like, it is preferable that the recovery rate can be increased and the quality can be increased.

  In view of the above problems, an object of the present invention is to provide a method for recovering valuable metals from printed circuit board waste that improves the recovery rate and quality of valuable metals from printed circuit board waste.

  The method for recovering valuable metals from printed circuit board waste according to the present invention includes a first step of pulverizing printed circuit board waste in one or two stages by an impact pulverizer, and a pulverized product after the printed circuit board waste is crushed. A second step of pulverizing by a final pulverizer, and a powdered material pulverized and generated by the final pulverizer separated into a powdery material mainly composed of valuable metals and the other by a wind power sorter; A third step of recovering the valuable metal from the body, and the first step, the second step, and the third step are continuously performed.

  According to the method for recovering valuable metals from printed circuit board waste according to the present invention, the recovery rate and quality of valuable metals from printed circuit board waste can be improved.

It is process drawing showing the process of a waste printed circuit board. It is FIG. (1) which shows the processing facility of a waste printed board. It is FIG. (2) which shows the processing facility of a waste printed board.

  FIG. 1 is a process diagram illustrating a process of processing a waste printed board. As illustrated in FIG. 1, the starting material is a waste printed board. In the present embodiment, the waste printed circuit board means a printed circuit board on which electronic components or the like are not mounted, a printed circuit board before mounting the electronic component (hereinafter referred to as a solid substrate), and a circuit on which the electronic component is mounted. In the substrate manufacturing process, a printed circuit board forming residue (hereinafter referred to as a frame substrate) generated by punching and a printed circuit board cut end (hereinafter referred to as a long substrate) generated by cutting are included.

(Preliminary grinding)
In the preliminary pulverization, for example, using a uniaxial pulverizer with a screen diameter of 50 mm, the size of the waste printed circuit board can be put into an impact pulverizer used for primary pulverization (for example, the vertical and horizontal lengths are 50 mm or less). To do. Of the waste printed circuit boards, those whose sizes are already large enough to be put into an impact pulverizer used for primary pulverization (for example, long substrates) are not preliminarily pulverized. Hereinafter, a waste printed circuit board having a size that can be charged into an impact pulverizer used in primary pulverization is referred to as printed circuit board waste.

(Primary grinding: part of the first step)
In the primary pulverization, the printed circuit board waste is pulverized using, for example, an impact pulverizer having a screen diameter of 15 mm. The impact pulverizer is preferably a hammer mill. Further, primary grinding may be omitted.

(Secondary grinding: part of the first step)
In the secondary pulverization, the printed circuit board waste pulverized by the primary pulverization is pulverized using, for example, an impact pulverizer having a screen diameter of 9 mm. The impact pulverizer is preferably a hammer mill.

(Third grinding: second step)
In the tertiary pulverization, the pulverized product obtained by the secondary pulverization is pulverized using a final pulverizer to obtain a powder having an average particle size (D50) of 200 μm to 360 μm. The final pulverizer is preferably an impact pulverizer, and more preferably a hammer mill or a high-speed hammer mill. The high-speed hammer mill is a hammer mill having a peripheral speed of 100 m / s or more. In this case, for example, a screen having a screen diameter of 2 mm, or a powder product having an average particle diameter (D50) of 200 μm to 360 μm can be obtained by airflow classification.

(Separation process: 3rd process)
In the separation step, the powder material is separated into a copper slag and the other by a wind sorter, and the copper slag is collected. The wind sorter separates two or more types of components based on the difference in specific gravity between them, and examples thereof include a variable impactor, a cyclone, and a micron separator (trade name).

(Recovery process)
In the recovery process, the resin is separated and recovered from the component containing the resin discharged in the separation process using a dust collector such as a bag filter. The resin thus obtained can be treated in an industrial waste incinerator or the like.

  FIG. 2 shows an example of a printed board scrap processing facility (substrate grinding facility) 100. The substrate crushing facility 100 in FIG. 2 is a facility for continuously performing from primary crushing to tertiary crushing.

  As shown in FIG. 2, the substrate crushing equipment 100 has hammer mills 10A and 10B as impact pulverizers used for primary pulverization and secondary pulverization, and a hammer as a final pulverizer used for tertiary pulverization. It has a mill 10C. In addition, the substrate crushing equipment 100 has a wind sorter 70 such as a micron separator used in the separation process. Although not shown, a bag filter, a fan, an exhaust duct, and the like are provided at the subsequent stage of the wind power sorter 70.

  Printed circuit board waste is put into the hammer mill 10A. When the printed circuit board waste is pulverized by the hammer mill 10A, it is discharged from the lower discharge port and conveyed upward by the vertical conveyor 20A. Then, the printed circuit board waste conveyed by the vertical conveyor 20A is put into the hopper 30A, and is put into the next hammer mill 10B by the screw feeder 40A provided below the hopper 30A.

  When the printed circuit board waste that has been primarily pulverized is input to the hammer mill 10B, it is further pulverized, and the pulverized material obtained by the pulverization is discharged from the lower discharge port and conveyed upward by the vertical conveyor 20B. The Then, the crushed material conveyed by the vertical conveyor 20B is put into the hopper 30B, and is put into the next hammer mill 10C by the screw feeder 40B provided below the hopper 30B.

  When the pulverized material obtained by the secondary pulverization is input to the hammer mill 10C, the pulverized material is further pulverized, and the powdered material obtained by the pulverization is discharged from the lower discharge port. A transport duct (pneumatic transport pipe) 60 that is directly connected to the wind power sorter 70 and forms a path is connected to the lower discharge port. For this reason, when the wind power sorter 70 starts operation, a suction force is generated in the transport duct 60. As a result, the powder discharged from the hammer mill 10 </ b> C is sucked and transported into the wind power sorter 70 through the transport duct 60.

  In the present embodiment, the discharge port at the lower part of the hammer mill 10 </ b> C and the wind sorter 70 are connected by the transport duct 60, and the powder material discharged from the hammer mill 10 </ b> C is sucked by the wind sorter 70 with the suction force of the wind sorter 70. In the wind power sorter 70, the copper slag can be separated.

  Further, in this embodiment, since the primary pulverization to the tertiary pulverization are continuously performed, it is not necessary for the operator to transport the pulverized material or the powder material between the hammer mills. The burden can be reduced.

  Here, when the primary pulverization to the tertiary pulverization are continuously executed using the substrate pulverization equipment 100 of FIG. 2, the three hammer mills 10A to 10C are operated independently to perform the primary pulverization to the tertiary pulverization. It was found that the quality of copper in the copper slag was reduced by about 20 to 30%, even though the recovery rate was the same as compared with the case where pulverization was performed.

  The present inventor has intensively studied this result, and when the discharge port at the lower part of the hammer mill 10C and the wind sorter 70 are connected by the transport duct 60, since the suction force is strong, the third pulverization is sufficiently performed. I noticed that there was a possibility that the crushed material was not sucked and transported. The inventor has developed a substrate crushing equipment 100 ′ as shown in FIG. 3 based on such knowledge.

  As shown in FIG. 3, the substrate crushing equipment 100 ′ is provided with a substrate crushing equipment 100 (FIG. 3) in which a hopper 50 having an open top is provided between the lower outlet of the hammer mill 10C and the transport duct 60. It is different from 2).

  In the substrate crushing equipment 100 ′ of FIG. 3, the powder material discharged from the lower discharge port is put into the hopper 50, and the powder material put into the hopper 50 is sucked by the suction force generated by the wind power sorter 70. It is transported in the transport duct 60. In the example of FIG. 3, since the outside air (free air) can be taken in from the upper opening of the hopper 50 at the time of this suction, the suction force is adjusted appropriately, and the conveying speed of the powder material is adjusted appropriately. It is like that. Thereby, the influence which a suction force has with respect to the 3rd grinding | pulverization performed within the hammer mill 10C can be suppressed. By doing in this way, it is possible to make the recovery rate and the quality of the copper in the copper basket equivalent to the case where the three hammer mills 10A to 10C are operated independently and the primary grinding to the tertiary grinding are executed. it can.

  In the example of FIG. 3, the case has been described in which free air is introduced by providing the hopper 50 between the lower outlet of the hammer mill 10 </ b> C and the transport duct 60, but is not limited thereto. For example, the transport duct 60 and the lower discharge port of the hammer mill 10C may be directly connected, and an intake port for taking in free air may be provided in a part of the lower discharge port of the transport duct 60 or the hammer mill 10C. Even in this case, since the suction force can be adjusted and the conveying speed of the powder can be adjusted, the same effect as that of FIG. 3 can be obtained.

  Further, as shown in FIGS. 2 and 3, the powder material crushed by the hammer mill 10C is transported to the wind power sorter 70 using the suction force of the wind power sorter 70, so that the powder material is transported. It is not necessary to prepare a device (such as a conveyor). Thereby, cost can be reduced.

  Further, according to the present embodiment, the printed circuit board waste is pulverized in one or two stages by an impact pulverizer, and the pulverized product after pulverizing the printed circuit board waste is pulverized by the final pulverizer to obtain an average particle diameter (D50 ) Can be sufficiently separated from the valuable metal and the substrate layer. As a result, the amount of valuable metal remaining attached to the substrate layer is reduced, so that the recovery efficiency of valuable metal can be improved. The impact pulverizer is preferably a hammer mill. In this case, it is preferable that the screen diameter of the hammer mill before the final pulverizer is 8 mm or more and 9 mm or less. The final pulverizer is preferably an impact pulverizer, more preferably a hammer mill or a high-speed hammer mill (a hammer mill having a peripheral speed of 100 m / s or more).

  In addition, according to the present embodiment, the printed circuit board waste is pulverized in one or two stages by an impact pulverizer, and the pulverized product after the printed circuit board crushed powder is crushed by the final pulverizer has an average particle diameter (D50) of 200 μm. Crushing to ~ 360 μm, separating the powder obtained by pulverization by the final pulverizer into a powdery substance mainly composed of valuable metals and the other by wind power sorter, and recovering valuable metals Thus, the recovery efficiency of valuable metals can be improved. In addition, it is preferable that a valuable metal is a copper cocoon.

  In addition, according to the present embodiment, the resin content can be efficiently recovered by recovering the powdery material mainly composed of the resin content classified by the wind power sorter with the bag filter.

  In the substrate crushing equipment 100 and 100 'shown in FIGS. 2 and 3, either one of the hammer mills 10A and 10B may be omitted, and crushing by an impact crusher may be performed in one stage.

Examples of the present invention will be described below, but the present invention is not limited to the examples.
(Examples 1-6)
The waste printed circuit board shown in Table 1 was used as a raw material, and the waste printed circuit board was pulverized under the indicated conditions. Table 2 shows the average particle diameter (D50) of the obtained powder. For comparison, a long substrate was used as a raw material, and primary pulverization and secondary pulverization were performed with a shearing pulverizer without preliminary pulverization. However, in the comparative example, at the end of the secondary pulverization, a sufficient pulverized product could not be obtained even visually, and the valuable metal and the substrate layer were not sufficiently peeled off. Grinding was stopped at the end.

  As shown in Table 2, in Examples 1-6, the average particle diameter (D50) of the obtained powder was 200-360 μm, and the printed circuit board waste could be pulverized into powder. Moreover, it was confirmed by visual observation that the printed circuit board waste was pulverized well and that the valuable metal and the substrate layer were sufficiently separated.

  Using a wind power sorter, copper slag and resin were collected from the powder obtained by the above pulverization treatment. Note that the copper quality and the amount of copper contained in the powder were measured and evaluated by the ICP method.

The total amount of powder 184 kg obtained in Examples 1 to 6 contained 50 kg of Cu, but was separated into 56 kg of copper cake and 128 kg of resin.
The copper grade of the recovered resin component was less than 5%, and it was revealed that the copper cocoon and the resin can be effectively separated, and that the copper cocoon component can be obtained with a high recovery rate.

  Although the embodiments of the present invention have been described in detail above, the present invention is not limited to such specific embodiments, and various modifications and changes can be made within the scope of the gist of the present invention described in the claims. It can be changed.

Claims (8)

A first step of crushing printed circuit board waste in one or two stages with an impact crusher;
A second step of pulverizing the pulverized product after pulverizing the printed circuit board waste with a final pulverizer;
A third step of separating the powdered material pulverized and generated by the final pulverizer into a powdery material mainly composed of valuable metals and the other by a wind power sorter and recovering the valuable metals from the powdered materials. And including
The said 1st process, the said 2nd process, and the said 3rd process are implemented continuously, The collection | recovery method of the valuable metal from printed circuit board waste characterized by the above-mentioned.   The method for recovering valuable metals from printed circuit board waste according to claim 1, wherein the powder obtained by the final pulverizer is conveyed to the wind power sorter by using the suction force of the wind power sorter. .   The intake port for taking in outside air is provided in a path connecting the final pulverizer and the wind power sorter, and the conveyance speed of the powder material obtained by the final pulverizer is adjusted. A method for recovering valuable metals from printed circuit board waste.   The one-stage or two-stage impact pulverizer and the final pulverizer are connected by a conveyor, and the pulverized material and the powdered material are continuously conveyed. A method for recovering valuable metals from printed circuit board waste according to one item.   The recovery of valuable metals from printed circuit board waste according to any one of claims 1 to 4, wherein the final pulverizer generates a powder having an average particle size (D50) of 200 µm to 360 µm. Method.   The method for recovering valuable metals from printed circuit board waste according to any one of claims 1 to 5, wherein the impact pulverizer is a hammer mill.   The method for recovering valuable metals from printed circuit board waste according to any one of claims 1 to 6, wherein the final pulverizer is an impact pulverizer.   8. The method for recovering valuable metals from printed circuit board waste according to claim 7, wherein the impact pulverizer is a hammer mill or a high-speed hammer mill.

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