JP2017074561A - Method for recovering non-ferrous metal from electronic substrate in composite waste - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method of effective and inexpensive recovering when recovering non-ferrous metals from an electronic substrate.SOLUTION: A method is provided which includes a crushing step of crushing a processing object into a predetermined dimension and a pyrolysis step of separating the crushed processing object into non-ferrous metals and plastics by heating in a substantially oxygen-free state, the method allowing a combustible gas generated in the pyrolysis step to be supplied to a power generator or to be used as the fuel source of the pyrolysis heating means. Preferably, before the pyrolysis step, further included is a wet specific gravity screening step of screening polyvinylchloride and others under gravity out of the processing object to remove polyvinylchloride.SELECTED DRAWING: Figure 1

Description

  The present invention relates to a method for recovering non-ferrous metals from electronic substrates in composite waste such as waste home appliances and scrap cars.

  Many electronic substrates are contained in composite waste such as waste home appliances and scrap cars. These electronic substrates contain a large amount of non-ferrous metal, and the content thereof is higher than the content in rocks mined from the mine. Therefore, it is desired to efficiently recover non-ferrous metals from these electronic substrates and effectively use them.

  However, in the conventional technology, it has been very expensive to recover the non-ferrous metal from the electronic substrate. That is, in order to recover non-ferrous metals, only non-ferrous metals may be extracted from the electronic substrate and carried to a refinery that is the final destination, but the electronic substrate contains a considerable amount of plastic. Since this plastic has a light specific gravity and a large volume compared to the weight, a large amount of plastic must be transported in addition to the non-ferrous metal to be collected, which is a cause of a great cost. In addition, since a conventional recovery plant consumes a large amount of power when the plant is operating, this point is also a cause of high costs.

  The present invention has been developed in such a situation, and an object of the present invention is to provide a method for efficiently recovering a non-ferrous metal from an electronic substrate at a low cost.

  A method for recovering non-ferrous metals from an electronic substrate according to claim 1 of the present application includes a crushing step of crushing an object to be processed to a predetermined size, and heating the crushed object to be processed in a substantially oxygen-free state. Including a pyrolysis step for separating metal and plastic, wherein the combustible gas generated in the pyrolysis step is supplied to a generator or used as a fuel source for heating means for pyrolysis It is.

  The method for recovering a non-ferrous metal from an electronic substrate according to claim 2 of the present invention is the method of claim 1, wherein prior to the pyrolysis step, polyvinyl chloride and other specific gravity are extracted from the material to be treated. The method further includes a wet specific gravity sorting step of sorting and removing polyvinyl chloride.

  The method for recovering non-ferrous metal from the electronic substrate according to claim 3 of the present application is the metal removal step of removing magnetic metal pieces from the object to be processed in the method of claim 2 prior to the wet specific gravity sorting step. Is further included.

  According to the method of the present invention, the object to be treated is separated into non-ferrous metal and plastic (carbide) in the pyrolysis step, so that only non-ferrous metal can be transported when transporting non-ferrous metal to the final smelter. The transportation cost and the storage cost are reduced. Moreover, by using the combustible gas generated in the thermal decomposition process for power generation or the like, it can be used as operating energy of the plant, and the operating cost can be reduced. Furthermore, since PVC is removed from the material to be treated in the wet specific gravity sorting process, generation of chlorine gas in the pyrolysis process is prevented, and the useful life of the inner cylinder of the pyrolysis machine can be extended.

It is the schematic diagram which showed the whole process of the nonferrous metal recovery method which concerns on preferable embodiment of this invention. It is a figure for demonstrating the principle of operation of the reticulated air chamber type wet specific gravity sorter used in the wet specific gravity classification process of the nonferrous metal recovery method of FIG. It is the figure which showed one form of the reticulated air chamber type wet specific gravity sorter. It is sectional drawing which showed the thermal decomposition machine used in the thermal decomposition process of the nonferrous metal recovery method of FIG.

  Next, with reference to the drawings, a method for recovering non-ferrous metal from an electronic substrate in composite waste according to a preferred embodiment of the present invention (hereinafter referred to as “non-ferrous metal recovery method”) will be described in detail. FIG. 1 is a schematic diagram showing the entire process of a nonferrous metal recovery method according to a preferred embodiment of the present invention.

(Crushing process)
First, a crushing step of crushing an electronic substrate to be processed (hereinafter referred to as “object to be processed”) into a predetermined size (for example, 8 mm diameter) is performed. In the crushing process, a normal crusher 10 may be used. The workpiece to be crushed by the crusher 10 is sent to an appropriate screen 12 (for example, a wind sorting vibration screen). Then, the screen 12 is sorted and only those having a predetermined dimension or less are supplied to the next process. The thing beyond a predetermined dimension is returned to the crusher 10, and is crushed so that it may become below a predetermined dimension.

  It should be noted that a constant amount of the object to be processed is supplied to the crusher 10 via the quantitative feeder 14 so that the crushing process is efficiently performed.

(Metal removal process)
Subsequently, the metal removal process which removes a magnetic metal piece from the to-be-processed object crushed below to the predetermined dimension is implemented. In the metal removal step, the magnetic metal pieces in the object to be processed are magnetized and removed using the magnetic sorter 16. The magnetic sorter 16 may use a normal one.

(Wet specific gravity sorting process)
Next, a wet specific gravity sorting process for sorting the workpieces from which the magnetic metal pieces have been removed for each specific gravity is performed. In the wet specific gravity sorting step, a reticulated air chamber type wet specific gravity sorter 18 is used. The reticulated air chamber type wet specific gravity sorter 18 is known per se, and is known as a machine that selectively recovers high quality coal mainly from raw coal.

  With reference to FIG. 2, the operation principle of the reticulated air chamber type wet specific gravity sorter 18 will be briefly described. The reticulated air chamber type wet specific gravity sorter 18 has a sorting chamber in which a substance to be sorted (object to be treated) is placed above, a pulsation chamber filled with water located below, and a sorting chamber, a pulsation chamber, A mesh is arranged between the two. An air chamber for entering / exiting air is arranged in the pulsation chamber, and the water level in the sorting chamber can be raised / lowered by raising / lowering the water level in the air chamber by entering / exiting air. By applying an appropriate pulsation of water to the object to be processed placed in the sorting chamber, a layer of a material having a specific gravity is formed in the sorting chamber.

  FIG. 3 is a cross-sectional view schematically showing an embodiment of the mesh air chamber type wet specific gravity sorter 18. The reticulated air chamber type wet specific gravity sorter 18 includes a sorting chamber 18a into which an object to be treated is charged, a pulsation chamber 18b filled with a sorting medium (for example, water), and between the sorting chamber 18a and the pulsation chamber 18b. A mesh 18c to be disposed and an air chamber 18d are provided. At the top of the sorting chamber 18a is a workpiece inlet 18e, at the side of the sorting chamber 18a is a workpiece discharge path 18f (two upper and lower portions are provided in this example), and at the bottom of the pulsation chamber 18b. Boxes 18g for storing heavy specific gravity are respectively provided, and a carry-out path (for example, bucket elevator) 18h for carrying out the heavy specific gravity extends upward from the box 18g.

  The wet specific gravity sorting process by the reticulated air chamber type wet specific gravity sorter 18 is performed as follows. The object to be processed from which the magnetic metal piece has been removed is charged into the sorting chamber 18a through the charging port 18e. Next, the water level in the air chamber 18d is raised and lowered by the entry / exit of air to give pulsation of water to the object to be processed in the sorting chamber 18a, whereby a layer of heavy specific gravity containing non-ferrous metal is contained in the sorting chamber 18a. A layer of plastic such as polyvinyl chloride (PVC), polyethylene (PE), polypropylene (PP), etc. is gradually formed. The heavy specific gravity containing non-ferrous metal falls through the mesh 18c and accumulates in the box 18g.

  As described above, the objects to be processed are sorted into heavy specific gravity containing non-ferrous metals, PVC, and plastics such as PE and PP. The heavy specific gravity containing non-ferrous metal is sent from the box 18g to the draining screen 20 via the carry-out path 18h, and after removing moisture there, it is sent to the next step. A normal draining screen 20 may be used. The PVC is discharged out of the sorting chamber 18a from the lower discharge path 18f and is disposed of for disposal. Plastics such as PE and PP are discharged from the upper discharge path 18f to the outside of the sorting chamber 18a, and all or a part thereof is sent to the next process.

  Since PVC is removed from the object to be treated in the wet specific gravity sorting step, generation of chlorine gas in the thermal decomposition step, which is the next step, is prevented. Thereby, since the inner wall of the inner cylinder of the pyrolyzer is not exposed to chlorine gas, a situation in which the useful life of the inner cylinder is shortened is avoided.

(Pyrolysis process)
Next, a pyrolysis step is carried out for pyrolyzing the heavy specific gravity containing the drained nonferrous metal. In the pyrolysis process, plastics such as PE and PP and non-ferrous metals are separated.

  The pyrolyzer 22 shown in FIG. 4 shows one form of the pyrolyzer used in the pyrolysis step, and was developed by one of the inventors. The pyrolyzer 22 is described in detail in Japanese Patent No. 3781379, but its components and operation will be briefly described.

  The pyrolyzer 22 includes a cylindrical outer cylinder 22a, an inner cylinder 22b rotatably disposed in the outer cylinder 22a, a heating means 22c disposed between the outer cylinder 22a and the inner cylinder 22b, A rotating mechanism 22d for rotating the cylinder 22b, a workpiece supply means 22e disposed at one end (the left end in FIG. 4) of the inner cylinder 22b, and the other end (the right end in FIG. 4) of the inner cylinder 22b. And an outlet 22f disposed at the bottom. The central axis of the inner cylinder 22b is inclined so that the left end is high and the right end is low as viewed in FIG. Both ends of the inner cylinder 22b are covered with heat insulating materials 22g and 22h. The rotation mechanism 22d supports the drive motor 22d1, the gear 22d2 fixed to the outer peripheral surface of the heat insulating material 22g, the transmission means 22d3 for transmitting the rotation drive of the drive motor 22d1 to the gear 22d2, and the inner cylinder 22b to be rotatable. The roller 22d4. The workpiece supply means 22e includes a hopper 22e1 and a screw feeder 22e2. Tar decomposition means 22i is provided inside the inner cylinder 22b. The tar decomposition means 22i is a device for removing tar from the untreated gas generated in the thermal decomposition process, and has a stopping chamber 22i1, a baffle plate 22i2, and a lid 22i3.

  The pyrolyzer 22 also includes a secondary decomposition unit 22j connected to the outlet 22f. The secondary decomposition unit 22j is an optional part, and includes a storage container 22j1, a gas discharge port 22j2, a discharge unit 22j3, and a secondary heating unit 22j4.

  The pyrolysis process by the pyrolyzer 22 is performed as follows. An object to be treated (heavy specific gravity containing non-ferrous metal from which moisture has been removed by the draining screen 20, PE and PP subjected to specific gravity selection) is supplied to the inner cylinder 22b via the hopper 22e1 and the screw feeder 22e2. The object to be processed supplied to the inner cylinder 22b is heated (400 ° C. to 700 ° C.) in a substantially oxygen-free state by the heating means 22, but the inner cylinder 22b is inclined and rotated. Therefore, the workpiece is gradually pyrolyzed and moves to the outlet 22f. The object to be treated is separated into a plastic such as PE or PP and a non-ferrous metal in the process of thermal decomposition, and the plastic becomes a carbide. The nonferrous metal and carbide separated in this way are sent to the next step.

  The combustible gas generated in the process of thermal decomposition of the workpiece is sent to the dual generator 24 that can use both light oil and gas as fuel through the gas discharge port 22j2, and is used in this method. It is used for the operation of facilities (such as the crusher 10, the reticulated air chamber type wet specific gravity sorters 18, 26, the pyrolyzer 22). If the combustible gas is liquefied using a compression device or a cooling device (both not shown), a diesel generator can be used instead of the dual generator 24. Further, the combustible gas may be supplied to the heating means (for example, LPG burner) 22c of the pyrolyzer 22 and used as a fuel source of the heating means instead of being sent to the generator.

(Residue separation process)
Next, a residue separation step for separating nonferrous metals and carbides is performed. In the residue separation step, a reticulated air chamber type wet specific gravity sorter 26 is used. The reticulated air chamber type wet specific gravity sorter 26 has substantially the same configuration as the reticulated air chamber type wet specific gravity sorter 18 used in the wet specific gravity sorting process.

  The separated non-ferrous metal is sent to a smelter after removing moisture by the draining screen 28. The carbide is provided for a desired use such as a regeneration treatment.

  The present invention is not limited to the above-described embodiments, and various modifications can be made within the scope of the invention described in the claims, and these are also included in the scope of the present invention. Needless to say, it is something.

  For example, the reticulated air chamber type wet specific gravity sorter and pyrolyzer described and illustrated in the above embodiment are merely examples, and other configurations can be used as long as they can obtain the same effect. You may use a specific gravity sorter and a pyrolyzer.

  Further, the water removed by the draining screens 20 and 28 is temporarily stored in a water storage tank (not shown), and can be used as a sorting medium in the reticulated air chamber type wet specific gravity sorters 18 and 20 when necessary. Good.

DESCRIPTION OF SYMBOLS 10 Crusher 12 Screen 14 Fixed feeder 16 Magnetic sorter 18 Reticulated air chamber type wet specific gravity sorter 18a Sorting chamber 18b Pulsating chamber 18c Mesh 18d Air chamber 18e Input port 18f Discharge channel 18g Box 18h Transport channel 20 Drain screen 22 Pyrolysis Machine 22a Outer cylinder 22b Inner cylinder 22c Heating means 22d Rotating mechanism 22e Workpiece supply means 22f Outlet 22g Thermal insulation material 22h Thermal insulation material 22i Tar decomposition means 22j Secondary decomposition section 24 Generator 26 Submerged air chamber type wet specific gravity sorter 28 Draining screen

Claims (3)

A method for recovering non-ferrous metals from electronic substrates in composite waste,
Crushing step of crushing the workpiece to a predetermined size;
A pyrolysis step of separating the crushed workpiece into non-ferrous metal and plastic by heating in a substantially oxygen-free state,
A method in which the combustible gas generated in the pyrolysis step is supplied to a generator or used as a fuel source of a heating means for pyrolysis.   2. The wet specific gravity selection step of removing polyvinyl chloride by performing specific gravity selection of polyvinyl chloride and other substances from the object to be treated prior to the pyrolysis step. Way.   3. The method according to claim 2, further comprising a metal removal step of removing magnetic metal pieces from the object to be processed prior to the wet specific gravity sorting step.

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