Efficient separation and recovery device for valuable metal of waste circuit board

Abstract

The invention discloses a waste circuit board valuable metal efficient separation and recovery device, and relates to the technical field of circuit board recovery, the waste circuit board valuable metal efficient separation and recovery device comprises a pre-crushing unit, a fine crushing unit, a screening and granularity regulation and control unit, a magnetic separation unit and a high-voltage electrostatic separation unit, the output end of the pre-crushing unit communicates with the input end of the fine crushing unit; the output end of the fine crushing unit is communicated with the input end of the screening and granularity regulation and control unit, the middle-layer output end of the screening and granularity regulation and control unit is connected with the input end of the magnetic separation unit, and a non-magnetic material outlet of the magnetic separation unit is connected with the input end of the high-voltage electrostatic separation unit. By adopting the separation process of magnetic separation and high-voltage electrostatic separation, the high-precision composite separation function is achieved, the magnetic separation unit can collect magnetic metal, high-voltage electrostatic separation has extremely high separation capacity on non-magnetic metal and non-metal particles, and the efficiency and stability of metal separation treatment are effectively improved.

Description

Technical Field

[0001] This invention relates to the field of circuit board recycling technology, specifically to a high-efficiency separation and recycling device for valuable metals in waste circuit boards. Background Technology

[0002] With the rapid development of the electronics industry and the accelerated pace of electronic product upgrades, a large number of waste circuit boards have been generated. Waste circuit boards contain valuable metals such as copper, gold, silver, palladium and tin, as well as harmful substances such as lead, mercury and brominated flame retardants. They are a typical type of electronic waste that is both resource-rich and hazardous. The key to their efficient resource recycling lies in achieving full dissociation and efficient separation of metals and non-metals (mainly resin fibers). Currently, common processing steps mainly include mechanical crushing, sorting, and subsequent smelting and purification. However, existing technologies have the following prominent problems: coarse crushing methods are difficult to fully expose and dissociate the metal encapsulated in the resin matrix, resulting in low recovery rates in subsequent sorting; excessive crushing leads to excessively fine metal fragmentation, generating a large amount of harmful dust, causing metal loss and environmental pollution; conventional sorting technologies have poor adaptability to crushed products and limited efficiency in separating metals from non-metals.

[0003] Patent document CN117920463B discloses a device and method for separating and recycling precious metals in waste circuit boards. The above patent realizes the function of evenly dispersing the material, so that the material can fully contact the discharge electrode group. It solves the problem that the material inside may not be dispersed due to the swinging when the reciprocating swing of the shell is used to assist the material in contacting the electrode unit.

[0004] The aforementioned patent uses three mixing mechanisms for materials—swinging, vibration, and blowing—to evenly disperse the materials and ensure they fully contact the discharge electrode assembly. This prevents some materials from failing to contact the discharge electrode assembly, which would otherwise prevent non-metallic materials from adsorbing onto the separation mesh, resulting in incomplete separation due to mixing of non-metallic materials with precious metals. However, the metal sorting efficiency remains low.

[0005] Therefore, this application proposes a high-efficiency separation and recycling device for valuable metals in waste circuit boards with high separation efficiency. Summary of the Invention

[0006] The purpose of this invention is to provide a highly efficient separation and recycling device for valuable metals in waste circuit boards, so as to solve the technical problem of low separation efficiency mentioned in the background art.

[0007] To achieve the above objectives, the present invention provides the following technical solution: a high-efficiency separation and recycling device for valuable metals in waste circuit boards, comprising a pre-crushing unit, a fine crushing unit, a screening and particle size control unit, a magnetic separation unit, and a high-voltage electrostatic separation unit. The output end of the pre-crushing unit is connected to the input end of the fine crushing unit via a first conveyor, and the output end of the fine crushing unit is connected to the input end of the screening and particle size control unit via a second conveyor. The screening and particle size control unit is divided into three layers. The output end of the upper layer is reconnected to the input end of the fine crushing unit via a third conveyor; the output end of the middle layer is connected to the input end of the magnetic separation unit via a fourth conveyor. The magnetic separation unit separates magnetic and non-magnetic materials. The non-magnetic material outlet of the magnetic separation unit is connected to the input end of the high-voltage electrostatic separation unit, which separates metal particles and resin particles.

[0008] Preferably, the pre-crushing unit is a box structure with a feeding hopper at the top of the box. The feeding hopper is connected to the feed inlet of the pre-crushing unit. Three sets of counter-rotating shearing blades are horizontally arranged inside the pre-crushing unit. The shearing blades perform preliminary crushing of the material. A discharge port is provided at the bottom of the box of the pre-crushing unit. A first conveyor is provided below the discharge port. The feed end of the first conveyor is located below the discharge port. The discharge end of the first conveyor extends obliquely upward and connects to the input end of the fine crushing unit.

[0009] Preferably, the fine crushing unit is a vertical cylindrical reinforced casing with a feed inlet at the top center of the casing. The discharge hood outlet of the first conveyor is precisely located above the feed inlet of the fine crushing unit. A material distributor is installed on the feed inlet flange of the fine crushing unit, located below and connected to the discharge hood of the first conveyor. A rotating shaft is vertically installed at the center of the interior of the fine crushing unit, with bearing seats supporting both ends of the shaft. Three mounting seats are equidistantly fitted on the shaft, each of which can be adjusted in height on the shaft. A moving cutter disc is fixedly installed around each mounting seat. Three sets of fixed cutter discs are fixedly installed on the inner wall of the casing of the fine crushing unit. A discharge port is located at the bottom of the casing of the fine crushing unit, and a second conveyor is located below the discharge port. The discharge end of the second conveyor extends obliquely upward and connects to the input end of the screening and particle size control unit.

[0010] Preferably, both the moving cutter head and the fixed cutter head are made of alloy steel and have replaceable blades embedded around their periphery. The fixed cutter head and the moving cutter head are arranged alternately, and the moving cutter head rotates synchronously at high speed with the rotating shaft, forming a crushing chamber between the moving cutter head and the fixed cutter head.

[0011] Preferably, the screening and particle size control unit is provided with a first vibrating screen and a second vibrating screen arranged laterally at an incline. Both the first and second vibrating screens are mounted on shock-absorbing springs built into the side wall of the screening and particle size control unit. The first vibrating screen is located above the second vibrating screen. A fine powder collection bin is provided at the bottom of the screening and particle size control unit. An upper discharge port is provided at a lower position in the incline direction of the first vibrating screen. A third conveyor is provided at the upper discharge port. A middle discharge port is provided at a lower position in the incline direction of the second vibrating screen. A fourth conveyor is provided at the middle discharge port. The input ends of the third and fourth conveyors are connected to the interior of the screening and particle size control unit. The output end of the third conveyor extends obliquely upward and connects to the feeder on the fine crushing unit. The output end of the fourth conveyor extends obliquely upward and connects to the input end of the magnetic separation unit.

[0012] Preferably, the screen opening of the first vibrating screen is 2mm and the screen opening of the second vibrating screen is 0.5mm. The material is separated into large material, ideal material and fine material by the first and second vibrating screens. The large material is returned to the fine crushing unit for further crushing by the third conveyor. The ideal material enters the magnetic separation unit for sorting by the fourth conveyor. The fine material falls directly into the fine powder collection bin.

[0013] Preferably, a vibrating feeder is installed on the top of the magnetic separation unit, the discharge end of the fourth conveyor is connected to the input end of the vibrating feeder, the output end of the vibrating feeder is connected to the feed inlet of the magnetic separation unit, a roller is vertically arranged at the center of the magnetic separation unit, a semi-annular strong magnetic block is fixedly installed inside the roller, a receiving hopper is arranged below one side of the strong magnetic block, a magnetic metal collecting hopper is arranged below the other side of the strong magnetic block, a distributor is installed at the bottom of the receiving hopper, and the distributor is connected to the input end of the high-voltage electrostatic separation unit.

[0014] Preferably, a feeding hopper is provided at the upper left of the high-voltage electrostatic separation unit. The bottom of the feeding hopper is connected to the input end of the feeding hopper, and the output end of the feeding hopper is connected to the feed inlet of the high-voltage electrostatic separation unit. A high-voltage power supply box is installed on the outer wall of the high-voltage electrostatic separation unit. A metal roller is horizontally arranged at the center of the high-voltage electrostatic separation unit. The metal roller is supported by an insulated bearing. A high-voltage ionization electrode wire parallel to the axis of the metal roller is arranged at the upper left of the metal roller. The high-voltage ionization electrode wire is 30-50mm away from the surface of the metal roller and is fixed on an insulated porcelain bottle. An electrostatic induction electrode plate is arranged at the rear right of the metal roller. The electrostatic induction electrode plate is arc-shaped and parallel to the axis of the metal roller. A brush fixed to the inner wall of the high-voltage electrostatic separation unit is arranged below the high-voltage ionization electrode wire. The brush is in close contact with the surface of the metal roller. A non-conducting product collection tank is arranged at the bottom of the high-voltage electrostatic separation unit below the brush, and a conducting product collection tank is arranged at the bottom of the high-voltage electrostatic separation unit below the electrostatic induction electrode plate.

[0015] Preferably, the high-voltage electrostatic separation unit adopts an insulated protective box structure. All components in the high-voltage electrostatic separation unit are encapsulated in the grounded metal box. The box provides mounting points for the bearing seats at both ends of the metal roller. A high-voltage power supply box is also installed on the outer wall of the box, and the high-voltage ionization electrode wire is connected to the power supply of the high-voltage power supply box.

[0016] Preferably, the first, second, and third conveyors are enclosed trough belt conveyors, and the fourth conveyor is a pneumatic conveyor.

[0017] Compared with the prior art, the beneficial effects of the present invention are: 1. This invention achieves efficient dissociation and particle size control by adopting a combination of "coarse shearing and fine crushing". The adjustable cutter head gap and speed enable selective crushing, allowing metals and non-metals to be effectively dissociated at an appropriate particle size, avoiding excessive pulverization of metals. Combined with multi-stage screening and closed-loop return design for coarse particles, it ensures the optimal particle size distribution of materials entering the sorting stage. 2. This invention achieves high-precision composite sorting by employing a sorting process of "magnetic separation + high-voltage electrostatic separation". The magnetic separation unit effectively removes and collects magnetic interference substances, while the high-voltage electrostatic separation has a strong sorting ability for non-magnetic metals and non-metal particles in the particle size range of 0.1-2.0mm, effectively improving the efficiency and stability of metal sorting and processing. 3. By installing a multi-stage screening and particle size control unit, this invention achieves precise particle size classification and control, ensuring that the particle size of the material entering the magnetic separation and electrostatic separation stages is strictly controlled within the preferred range. This not only effectively avoids excessive crushing of qualified particle size materials, but also significantly improves the separation efficiency and accuracy of the magnetic separation and electrostatic separation units. At the same time, it reduces the ineffective energy consumption and equipment burden caused by processing materials of all particle sizes, and reduces operation and maintenance costs. 4. By adopting a fully enclosed design, this invention achieves full-process linkage, forming a stable and continuous material flow, reducing material loss and dust pollution. While ensuring a stable metal recovery rate, it also effectively inhibits the diffusion of dust and volatile organic compounds, meeting environmental protection requirements. Attached Figure Description

[0018] Figure 1 This is a schematic diagram of the overall cross-sectional structure of the present invention; Figure 2 This is a schematic diagram of the pre-crushing unit structure of the present invention; Figure 3 This is a schematic diagram of the fine crushing unit structure of the present invention; Figure 4 This is a schematic diagram of the sieving and particle size control unit structure of the present invention; Figure 5 This is a schematic diagram of the magnetic separation unit structure of the present invention; Figure 6 This is a schematic diagram of the high-voltage electrostatic sorting unit structure of the present invention.

[0019] In the diagram: 1. Pre-crushing unit; 2. Fine crushing unit; 3. Screening and particle size control unit; 4. Magnetic separation unit; 5. High-voltage electrostatic separation unit; 6. First conveyor; 7. Second conveyor; 8. Third conveyor; 9. Fourth conveyor; 10. Feeding hopper; 11. Shearing shaft; 12. Distributor; 13. Rotating shaft; 14. Mounting base; 15. Moving cutter disc; 16. Fixed cutter disc; 17. First vibrating screen; 18. Second vibrating screen; 19. Shock-absorbing spring; 20. Fine powder collection bin; 21. Vibrating feeder; 22. Drum; 23. Strong magnetic block; 24. Magnetic metal collection hopper; 25. Receiving hopper; 26. Distributor; 27. Feeding hopper; 28. High-voltage power supply box; 29. ​​Metal roller; 30. High-voltage ionization electrode wire; 31. Electrostatic induction electrode plate; 32. Brush; 33. Non-conducting product collection tank; 34. Conducting product collection tank. Detailed Implementation

[0020] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0021] In the description of this invention, it should be noted that the terms "upper," "lower," "inner," "outer," "front end," "rear end," "both ends," "one end," and "the other end," etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are used only for the convenience of describing this invention and for simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this invention. Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0022] In the description of this invention, it should be noted that, unless otherwise explicitly specified and limited, the terms "installed," "equipped with," "connected," etc., should be interpreted broadly. For example, "connection" can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection or an indirect connection through an intermediate medium; it can be a connection within two components. Those skilled in the art can understand the specific meaning of the above terms in this invention according to the specific circumstances.

[0023] Example 1: Please refer to Figure 1 , Figure 2 , Figure 3 , Figure 4 , Figure 5 and Figure 6 A high-efficiency separation and recycling device for valuable metals in waste circuit boards includes a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5. The output end of the pre-crushing unit 1 is connected to the input end of the fine crushing unit 2 via a first conveyor 6. The output end of the fine crushing unit 2 is connected to the input end of the screening and particle size control unit 3 via a second conveyor 7. The screening and particle size control unit 3 is divided into three layers. The output end of the upper layer is reconnected to the input end of the fine crushing unit 2 via a third conveyor 8. The output end of the middle layer is connected to the input end of the magnetic separation unit 4 via a fourth conveyor 9. The magnetic separation unit 4 separates magnetic and non-magnetic materials. The non-magnetic material outlet of the magnetic separation unit 4 is connected to the input end of the high-voltage electrostatic separation unit 5. The high-voltage electrostatic separation unit 5 separates metal particles and resin particles. The first conveyor 6, the second conveyor 7 and the third conveyor 8 are enclosed trough belt conveyors, and the fourth conveyor 9 is a pneumatic conveyor; Furthermore, this embodiment details the overall structure and process flow of the separation and recycling device. The device, through a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5 connected in sequence, achieves the gradual dissociation, enrichment, and separation of valuable metals in waste circuit boards. The feeding hopper 10 at the top of the pre-crushing unit 1 receives the material. The material after preliminary crushing is transferred to the fine crushing unit 2 by the first conveyor 6. A distributor 12 is provided between the discharge end of the first conveyor 6 and the feed inlet of the fine crushing unit 2, which can make the material fall into the subsequent crushing chamber evenly and controllably, avoiding load fluctuations caused by uneven feeding. The fine crushing unit 2 adopts a vertical cylindrical shell, and its internal crushing mechanism further crushes the material to a smaller particle size. The crushed material is transported to the screening and particle size control unit 3 by the second conveyor 7. The screening and particle size control unit 3 is equipped with two layers of horizontally inclined vibrating screens. The upper first vibrating screen 17 has a screen opening of 2.0 mm, and the lower second vibrating screen 18 has a screen opening of 0.5 mm. The first vibrating screen 17 and the second vibrating screen 18 accurately separate the material from the fine crushing unit 2 into three grades: large particles larger than 2.0 mm, "ideal particle size" particles between 0.5 and 2.0 mm, and fine particles smaller than 0.5 mm. Among them, the large particles are directly fed back to the feed end of the fine crushing unit 2 via the third conveyor 8, forming a "closed-loop crushing" cycle to ensure that all materials can be crushed to below the target particle size, thereby maximizing the degree of metal dissociation and avoiding over-crushing of qualified materials. The "ideal particle size" material between 0.5 and 2.0 mm is identified as the particle size class with sufficient dissociation between metal and non-metal and most suitable for subsequent physical separation. They are sent to the magnetic separation unit 4 via the fourth conveyor 9. The magnetic separation unit 4 feeds the material from the screening and particle size control unit 3 evenly onto the surface of the magnetic separation drum 22 via the vibrating feeder 21. The semi-annular strong magnetic block 23 fixedly installed inside the drum 22 generates a high-intensity magnetic field, which adsorbs the magnetic particles in the flowing material and carries them away from the material drop area as the drum 22 rotates, eventually falling into the magnetic metal collection hopper 24. The remaining non-magnetic materials (such as copper, aluminum and resin) are not adsorbed and fall by inertia into the receiving hopper 25. The distributor 26 at the bottom of the receiving hopper 25 distributes the non-magnetic materials to the subsequent high-voltage electrostatic separation unit 5. The high-voltage electrostatic separation unit 5 is the final step in separating non-magnetic metals from resin. The material is evenly spread onto the surface of a horizontally rotating, grounded metal roller 29 via a feed hopper 27. A high-voltage ionization electrode wire 30, parallel to the upper left of the metal roller 29, is supplied with tens of thousands of volts of negative DC voltage, ionizing the surrounding air and generating a large number of negative ions. These negative ions collide with all particles on the surface of the metal roller 29, causing both conductors (metals) and non-conductors (resin) to acquire a negative charge. Due to the good conductivity of the metal particles, the acquired charge can be quickly conducted away through the metal roller 29; while the resin particles have poor conductivity. The charge is difficult to dissipate and remains charged. During the subsequent rotation, the resin particles with residual negative charge are attracted by the electrostatic image force generated by the electrostatic induction electrode plate 31 behind the metal roller 29, thus adhering more tightly to the surface of the metal roller 29. Conversely, the discharged metal particles are mainly affected by gravity and centrifugal force. Ultimately, the metal particles detach from the surface of the metal roller 29 earlier and fall into the conductor product collection tank 34. The resin particles are attached and carried to the bottom of the metal roller 29, where they are forcibly brushed off by the brush 32 and fall into the non-conductor product collection tank 33, thus completing the efficient separation of metal and resin. The first conveyor 6, the second conveyor 7, and the third conveyor 8 are all enclosed trough belt conveyors of this type. Their core structure is a completely sealed box-shaped shell made of steel plate. The shell completely encloses the conveyor belt carrying the material, its idlers, drive rollers, and tensioning devices. At the top of the shell, multiple circular interfaces are provided at key locations along the conveying path for connecting to the suction pipes of an external dust collection system. This creates negative pressure suction at material drop-off and receiving points, where dust is easily generated. Simultaneously, transparent observation windows with sealing strips are installed at regular intervals on both sides of the shell, allowing operators to easily inspect the internal material transport and whether the belt is misaligned. At the head, tail, and middle sections... The unit is equipped with a lockable maintenance door for easy belt maintenance, cleaning, and troubleshooting. The enclosed structure effectively confines dust and volatile substances generated during crushing and screening within the unit. The fourth conveyor 9 is a pneumatic conveyor, which achieves complete sealing of the conveying process, preventing dust leakage. At the same time, it can flexibly transport materials across long distances or complex spatial layouts. It is suitable for accurately and cleanly transferring intermediate products after screening to the magnetic separation unit 4. The enclosed design achieves clean and dust-free transfer throughout the process, eliminating the workshop pollution problems caused by traditional open conveying and ensuring the environmental protection and continuous stable operation of the overall recycling process.

[0024] Example 2: Please refer to Figure 1 , Figure 2 and Figure 3A high-efficiency separation and recycling device for valuable metals in waste circuit boards includes a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5. The pre-crushing unit 1 has a box structure and a feeding hopper 10 is provided on the top of the box. The feeding hopper 10 is connected to the feed inlet of the pre-crushing unit 1. Three sets of counter-rotating shearing shafts 11 are horizontally arranged inside the pre-crushing unit 1. The shearing shafts 11 perform preliminary crushing of the material. A discharge port is provided at the bottom of the box of the pre-crushing unit 1. A first conveyor 6 is provided below the discharge port. The feed end of the first conveyor 6 is located below the discharge port. The discharge end of the first conveyor 6 extends obliquely upward and is connected to the input end of the fine crushing unit 2. The fine crushing unit 2 is a vertical cylindrical reinforced casing with a feed inlet at the top center of the casing. The discharge hood outlet of the first conveyor 6 is precisely located above the feed inlet of the fine crushing unit 2. A distributor 12 is installed on the feed inlet flange of the fine crushing unit 2. The distributor 12 is located below the discharge hood of the first conveyor 6 and is connected to the discharge hood. A rotating shaft 13 is vertically installed at the center of the interior of the fine crushing unit 2. Both ends of the rotating shaft 13 are supported by bearing seats. Three mounting seats 14 are equidistantly sleeved on the rotating shaft 13. The height position of each mounting seat 14 can be adjusted on the rotating shaft 13. A moving cutter disc 15 is fixedly installed on the periphery of each mounting seat 14. Three sets of fixed cutter discs 16 are fixedly installed on the inner wall of the casing of the fine crushing unit 2. A discharge port is provided at the bottom of the casing of the fine crushing unit 2. A second conveyor 7 is provided below the discharge port. The discharge end of the second conveyor 7 extends obliquely upward and is connected to the input end of the screening and particle size control unit 3. Both the moving cutter head 15 and the fixed cutter head 16 are made of alloy steel and have replaceable blades inlaid around the cutter head. The fixed cutter head 16 and the moving cutter head 15 are arranged alternately. The moving cutter head 15 rotates synchronously at high speed with the rotating shaft 13, forming a crushing chamber between the moving cutter head 15 and the fixed cutter head 16. Furthermore, this embodiment focuses on the pre-crushing unit 1 and the fine crushing unit 2 of the device, and elaborates on the specific structure for achieving efficient and controllable separation. The pre-crushing unit 1 adopts a box-type structure and has three sets of counter-rotating shearing blades 11 arranged horizontally inside the box. Compared with hammer or impact crushing, the shearing crushing method of the shearing blades 11 can generate huge shearing force on the relatively tough circuit board substrate, thereby tearing and shearing it into sheet or block materials with a size of less than 50mm. At the same time, it avoids excessive impact crushing and reduces the generation of initial dust. The pre-crushed material falls directly from the discharge port at the bottom of the box into the receiving trough of the first conveyor 6 below. The discharge end of the first conveyor 6 extends upward at an angle, smoothly lifting the material in the closed conveying channel to the top feed port of the fine crushing unit 2. The fine crushing unit 2 enables fine and selective crushing of materials. It employs a vertical cylindrical casing with a high-speed rotating shaft 13 vertically mounted at the center, driven by a high-power motor. Three axially adjustable mounting seats 14 are fitted onto the shaft 13, each mounting seat 14 fixing a movable cutter disc 15. Correspondingly, three sets of fixed cutter discs 16 are fixedly mounted on the inner wall of the casing. The movable and fixed cutter discs 15 are arranged alternately, forming an axial crushing chamber between them. Replaceable carbide blades are embedded around the cutting edges of both the movable and fixed cutter discs 15 and 16. By adjusting the height of the mounting seat 14 on the rotating shaft 13, the axial clearance between the movable cutter disc 15 and the adjacent fixed cutter disc 16 can be precisely changed. This clearance is a key parameter for controlling the crushed particle size: a larger clearance results in a larger output particle size. The coarser particle size increases processing capacity; the smaller gap allows for more thorough crushing and finer output particle size. Combined with the adjustment of the rotation speed of the shaft 13, the operator can flexibly select either a light crushing mode of "high speed and large gap" or a powerful fine crushing mode of "low speed and small gap" according to the nature of the incoming material and the particle size of the target product. This design allows the fine crushing unit 2 to selectively crush and peel off the resin matrix encapsulating the metal, while minimizing the excessive crushing of the metal particles into fine powder that is not conducive to sorting. The distributor 12 installed on the top of the fine crushing unit 2 ensures that the material from the first conveyor 6 is evenly distributed circumferentially along the feed inlet, preventing the material from accumulating on one side, which would lead to uneven wear of the cutter head and a decrease in crushing efficiency. The crushed material is discharged from the discharge port at the bottom of the casing and is conveyed to the screening and particle size control unit 3 by the second conveyor 7.

[0025] Example 3: Please refer to Figure 1 and Figure 4 A high-efficiency separation and recycling device for valuable metals from waste circuit boards includes a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5. The screening and particle size control unit 3 has a first vibrating screen 17 and a second vibrating screen 18 arranged laterally at an incline. Both the first vibrating screen 17 and the second vibrating screen 18 are mounted on shock-absorbing springs 19 built into the side wall of the screening and particle size control unit 3. The first vibrating screen 17 is located above the second vibrating screen 18. A fine powder collection bin 2 is located at the bottom of the screening and particle size control unit 3. 0. An upper discharge port is provided at a lower position in the inclined direction of the first vibrating screen 17, and a third conveyor 8 is provided at the upper discharge port. A middle discharge port is provided at a lower position in the inclined direction of the second vibrating screen 18, and a fourth conveyor 9 is provided at the middle discharge port. The input ends of the third conveyor 8 and the fourth conveyor 9 are both connected to the interior of the screening and particle size control unit 3. The output end of the third conveyor 8 extends obliquely upward and is connected to the distributor 12 on the fine crushing unit 2. The output end of the fourth conveyor 9 extends obliquely upward and is connected to the input end of the magnetic separation unit 4. The first vibrating screen 17 has a screen aperture of 2.0 mm, and the second vibrating screen 18 has a screen aperture of 0.5 mm. The material is separated into large material, ideal material and fine material by the first vibrating screen 17 and the second vibrating screen 18. The large material is returned to the fine crushing unit 2 for further crushing by the third conveyor 8; the ideal material enters the magnetic separation unit 4 for sorting by the fourth conveyor 9; and the fine material falls directly into the fine powder collection bin 20. Furthermore, this embodiment details the structure of the screening and particle size control unit 3 and its key role in optimizing the overall sorting efficiency. The screening and particle size control unit 3 is a module that integrates grading, diversion and closed-loop circulation functions. Its main body is a sealed screen box, inside which a first vibrating screen 17 and a second vibrating screen 18 are installed at an angle from top to bottom. The first vibrating screen 17 and the second vibrating screen 18 are supported by shock-absorbing springs 19 embedded in the side walls and driven by a vibrating motor to perform high-frequency linear vibration, which promotes the stratification and screening of materials on the screen surface. The screen hole diameter of the first vibrating screen 17 is 2.0 mm, and the screen hole diameter of the second vibrating screen 18 is 0.5 mm. The mixture from the fine crushing unit 2 first falls onto the first vibrating screen 17. Particles larger than 2.0 mm cannot pass through the screen and slide along the inclined screen surface to the upper discharge port at the lower end. They are then transported back to the feed end of the fine crushing unit 2 by the third conveyor 8. The closed-loop design of the return crushing ensures that all materials can only leave the crushing-screening cycle after being crushed to below 2.0 mm, thereby forcibly achieving full separation of metals and non-metals. Particles that pass through the first vibrating screen 17 but are retained by the second vibrating screen 18 have a particle size between 0.5 and 2.0 mm. This portion of the material is considered the "ideal separation particle size" because within this range, metal particles and resin particles are usually completely separated and have sufficient mass and size difference to facilitate efficient subsequent magnetic and electrostatic separation. They are discharged from the middle outlet of the second vibrating screen 18 and are directionally conveyed to the input end of the magnetic separation unit 4 by the fourth conveyor 9. Fine particles smaller than 0.5 mm that pass through the second vibrating screen 18 fall directly to the bottom of the screen box. The fine powder collection bin 20 contains resin powder and a small amount of extremely fine metal. Its physical properties (large specific surface area, easy dust generation and strong electrostatic adsorption) are not suitable for sorting in the main process. It can be used as secondary raw material for separate processing or safe disposal. Through this precise three-stage screening, the screening and particle size control unit 3 not only provides uniform and suitable raw materials for subsequent sorting processes, greatly improving sorting accuracy and efficiency, but also actively separates the difficult-to-handle fine powder, reducing the load and energy consumption of the main sorting system, and effectively reducing the circulation and generation of dust in the device.

[0026] Example 4: Please refer to Figure 1 and Figure 5 A high-efficiency separation and recycling device for valuable metals in waste circuit boards includes a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5. A vibrating feeder 21 is installed on the top of the magnetic separation unit 4. The discharge end of the fourth conveyor 9 is connected to the input end of the vibrating feeder 21. The output end of the vibrating feeder 21 is connected to the feed inlet of the magnetic separation unit 4. A roller 22 is vertically arranged at the center of the magnetic separation unit 4. A semi-annular strong magnetic block 23 is fixedly installed inside the roller 22. A receiving hopper 25 is arranged below one side of the strong magnetic block 23. A magnetic metal collection hopper 24 is arranged below the other side of the strong magnetic block 23. A distributor 26 is installed at the bottom of the receiving hopper 25. The distributor 26 is connected to the input end of the high-voltage electrostatic separation unit 5. Furthermore, this embodiment describes the specific structure and working process of the magnetic separation unit 4 for removing ferromagnetic materials. The task of the magnetic separation unit 4 is to pre-separate the ferromagnetic part of the material with a particle size of 0.5-2.0mm from the screening and particle size control unit 3 to avoid them interfering with the subsequent high-voltage electrostatic separation. The material is fed into the vibrating feeder 21 through the fourth conveyor 9. The vibrating feeder 21 is an electromagnetic vibrating feeder with adjustable amplitude and frequency, which can convert the material flow from the fourth conveyor 9 into a thin, uniform and continuous material curtain to ensure magnetic separation efficiency. The uniform thin layer of material is accurately fed into the upper surface of the magnetic separation drum 22. The core of the magnetic separator drum 22 is an outer cylinder made of a non-magnetic material (such as stainless steel). Inside the cylinder, a semi-annular strong magnetic block 23 is fixedly installed. The strong magnetic block 23 is made of high-performance neodymium iron boron permanent magnet material and can generate a surface magnetic field strength of not less than 0.8 Tesla on the surface of the drum 22. When the drum 22 is driven to rotate by a motor, the strong magnetic block 23 inside remains stationary. When the ferromagnetic particles in the material pass through the high-intensity magnetic field area, they are firmly attracted by the magnetic force to the surface of the drum 22 and rotate with the drum 22. When the drum 22 carries these magnetic particles to the side away from the magnetic system (i.e., the area without a magnetic field), the magnetic force disappears or is greatly weakened. The magnetic particles then detach from the drum 22 under their own gravity or centrifugal force and fall into the specially set magnetic metal collection hopper 24, thus being effectively recovered. For non-magnetic materials, they are not attracted by magnetic fields or the attraction force is very weak. Therefore, they are directly thrown off the surface of the roller 22 due to inertia near the feeding point and fall into the receiving hopper 25. The distributor 26 connected to the bottom of the receiving hopper 25 stably and controllably distributes the material to the downstream high-voltage electrostatic separation unit 5. The magnetic separation unit 4 completes the first stage of metal separation efficiently and reliably through the cooperation of the strong magnetic roller 22 and the precision feeding, creating favorable conditions for subsequent finer electrostatic separation.

[0027] Example 5: Please refer to Figure 1 and Figure 6 A high-efficiency separation and recycling device for valuable metals from waste circuit boards includes a pre-crushing unit 1, a fine crushing unit 2, a screening and particle size control unit 3, a magnetic separation unit 4, and a high-voltage electrostatic separation unit 5. A feed hopper 27 is located at the upper left of the high-voltage electrostatic separation unit 5. The bottom of a receiving hopper 25 is connected to the input end of the feed hopper 27, and the output end of the feed hopper 27 is connected to the inlet of the high-voltage electrostatic separation unit 5. A metal roller 29 is horizontally arranged at the center of the high-voltage electrostatic separation unit 5, supported by an insulated bearing. A high-voltage ionization electrode wire 30, parallel to the axis of the metal roller 29, is located at the upper left of the metal roller 29. The high-voltage ionization electrode wire 30 is 30-50mm away from the surface of the metal roller 29 and is fixed on the insulating porcelain bottle. An electrostatic induction electrode plate 31 is set at the right rear of the metal roller 29. The electrostatic induction electrode plate 31 is arc-shaped and parallel to the axis of the metal roller 29. Below the high-voltage ionization electrode wire 30, a brush 32 is fixed to the inner wall of the high-voltage electrostatic separation unit 5. The brush 32 is in close contact with the surface of the metal roller 29. A non-conductor product collection tank 33 is set at the bottom of the high-voltage electrostatic separation unit 5 below the brush 32. A conductor product collection tank 34 is set at the bottom of the high-voltage electrostatic separation unit 5 below the electrostatic induction electrode plate 31. The high-voltage electrostatic sorting unit 5 adopts an insulated protective box structure. All components inside the high-voltage electrostatic sorting unit 5 are encapsulated in the grounded metal box. The box provides mounting points for the bearing seats at both ends of the metal roller 29. A high-voltage power supply box 28 is also installed on the outer wall of the box. The high-voltage ionization electrode wire 30 is connected to the power supply of the high-voltage power supply box 28. Furthermore, this embodiment provides an in-depth analysis of the internal structure of the high-voltage electrostatic separation unit 5 and the physical realization process of electrostatic separation. The high-voltage electrostatic separation unit 5 is a refining step that achieves the final separation of non-magnetic metals such as copper from resin. After magnetic separation, the mixed material enters the feed hopper 27 of the high-voltage electrostatic separation unit 5 through the distributor 26. The bottom of the feed hopper 27 is provided with an adjustable slit to ensure that the material can be evenly scattered onto the surface of the horizontally placed grounded metal roller 29 in a single-particle layer. The metal roller 29 is supported by an insulated bearing and driven by a variable frequency motor. Its rotation speed can be adjusted within the range of 20-120 rpm to control the residence time of the material in the electric field area. At a distance of 30-50mm from the upper left of the surface of the metal roller 29, a high-voltage ionization electrode wire 30 is taut parallel to the axis of the metal roller 29. The high-voltage ionization electrode wire 30 is connected to a -20kV to -50kV negative high-voltage DC power supply output from the external high-voltage power supply box 28 of the high-voltage electrostatic separation unit 5. Under extremely high voltage, a strong corona discharge occurs around the high-voltage ionization electrode wire 30, ionizing the air and generating a large number of free electrons and negative ions. These negative ions fly towards the grounded metal roller 29 under the action of the electric field, colliding with and attaching to all the material particles on the surface of the metal roller 29, making them all negatively charged. At this time, the negative charge acquired on the surface of highly conductive metal particles (such as copper and aluminum) can be instantly conducted to the ground due to contact with the grounded metal roller 29, thereby restoring or approaching electrical neutrality of the metal particles; while the non-conductive resin particles... The charge cannot be quickly conducted away, so a stable negative charge accumulates on the surface. As these particles continue to rotate with the metal roller 29, they enter the electrostatic field region generated by the electrostatic induction electrode plate 31. The electrostatic induction electrode plate 31 is an arc concentric with the metal roller 29 and is placed parallel to the right rear of the metal roller 29. The electrostatic induction electrode plate 31 is usually grounded or applied with a relatively low bias voltage. The charged resin particles in this region will be attracted by a mirror attraction pointing towards the metal roller 29, thus adhering more firmly to the surface of the metal roller 29. Conversely, the discharged, nearly neutral metal particles are mainly affected by gravity, centrifugal force and friction of the metal roller 29. Due to the high density and inertia of the metal, they usually detach from the metal roller 29 when they rotate to the top of the metal roller 29 and are thrown out with a certain parabolic trajectory, eventually falling into the conductor product collection tank 34 located below. The resin particles that remain attached to the surface of the metal roller 29 are carried and rotated to the bottom area of ​​the roller. Here, the conductive nylon brush 32 mounted on the frame maintains close contact with the surface of the metal roller 29. The brush 32 forcibly scrapes the resin particles off the metal roller 29, causing them to fall into the non-conductive product collection tank 33 directly below. By precisely adjusting the voltage of the high-voltage ionization electrode wire 30, the distance between it and the metal roller 29, the rotation speed of the metal roller 29, and the position and potential of the electrostatic induction electrode plate 31, the intensity of corona charging and electrostatic separation can be optimized. Thus, a high metal recovery rate and resin product purity can be obtained within a wide range of feeding rates and material composition fluctuations. The high-voltage electrostatic separation unit 5 adopts an insulated protective box design, and all its internal high-voltage components are sealed in a grounded metal box to ensure operational safety.

[0028] Working principle: Waste circuit board substrates first enter the pre-crushing unit 1 through the feeding hopper 10, where they are initially crushed by the shearing blade shaft 11. After crushing, the material is transferred by the first conveyor 6 and evenly fed into the fine crushing unit 2 by the distributor 12. In the fine crushing unit 2, the material is finely crushed in the crushing chamber formed by the high-speed rotating moving cutter disc 15 and the fixed cutter disc 16. After crushing, the material is sent to the screening and particle size control unit 3 by the second conveyor 7. In the screening and particle size control unit 3, the material is classified by passing through the upper first vibrating screen 17 and the lower second vibrating screen 18. Large particles are returned to the fine crushing unit 2 for further crushing via the third conveyor 8, forming a closed loop. Ideal materials with a particle size between 0.5-2.0mm are sent to the magnetic separation unit 4 via the fourth conveyor 9; particles smaller than 0.5mm are sent to the magnetic separation unit 4. Fine powder of 5mm falls into fine powder collection bin 20. Ideal material is evenly distributed on the surface of strong magnetic roller 22 by vibrating feeder 21 in magnetic separation unit 4. Ferromagnetic metal is adsorbed and collected, while the remaining non-magnetic material falls into receiving hopper 25 and is distributed to high-voltage electrostatic separation unit 5 by distributor 26. In high-voltage electrostatic separation unit 5, the material is evenly sprinkled onto the surface of grounded metal roller 29. After being charged by high-voltage ionization electrode wire 30, the charge on the metal particles with good conductivity is quickly conducted away. Under the action of gravity and centrifugal force, they detach from metal roller 29 earlier and fall into conductor product collection tank 34. Non-conductive resin particles are electrostatically adsorbed on the surface of metal roller 29 due to residual charge and are finally peeled off by brush 32 and fall into non-conductive product collection tank 33, thereby achieving efficient and clean separation of metal and resin.

[0029] It will be apparent to those skilled in the art that the present invention is not limited to the details of the exemplary embodiments described above, and that the invention can be implemented in other specific forms without departing from its spirit or essential characteristics. Therefore, the embodiments should be considered in all respects as exemplary and non-limiting, and the scope of the invention is defined by the appended claims rather than the foregoing description. Thus, all variations falling within the meaning and scope of equivalents of the claims are intended to be included within the present invention. No reference numerals in the claims should be construed as limiting the scope of the claims.

Claims

1. A highly efficient device for separating and recycling valuable metals from waste circuit boards, characterized in that: The system includes a pre-crushing unit (1), a fine crushing unit (2), a screening and particle size control unit (3), a magnetic separation unit (4), and a high-voltage electrostatic separation unit (5). The output end of the pre-crushing unit (1) is connected to the input end of the fine crushing unit (2) via a first conveyor (6). The output end of the fine crushing unit (2) is connected to the input end of the screening and particle size control unit (3) via a second conveyor (7). The screening and particle size control unit (3) is divided into three layers. The output end of the upper layer is reconnected to the input end of the fine crushing unit (2) via a third conveyor (8). The output end of the middle layer is connected to the input end of the magnetic separation unit (4) via a fourth conveyor (9). The magnetic separation unit (4) separates magnetic and non-magnetic materials. The non-magnetic material outlet of the magnetic separation unit (4) is connected to the input end of the high-voltage electrostatic separation unit (5). The high-voltage electrostatic separation unit (5) separates metal particles and resin particles.

2. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: The pre-crushing unit (1) is a box structure, and a feeding hopper (10) is provided on the top of the box. The feeding hopper (10) is connected to the feed port of the pre-crushing unit (1). Three sets of counter-rotating shearing blades (11) are horizontally arranged inside the pre-crushing unit (1). The shearing blades (11) perform preliminary crushing on the material. A discharge port is provided at the bottom of the box of the pre-crushing unit (1). A first conveyor (6) is provided below the discharge port. The feed end of the first conveyor (6) is located below the discharge port. The discharge end of the first conveyor (6) extends obliquely upward and connects to the input end of the fine crushing unit (2).

3. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: The fine crushing unit (2) is a vertical cylindrical reinforced housing with a feed inlet at the top center of the housing. The discharge hood outlet of the first conveyor (6) is precisely located above the feed inlet of the fine crushing unit (2). A feeder (12) is installed on the feed inlet flange of the fine crushing unit (2). The feeder (12) is located below the discharge hood of the first conveyor (6) and connected to the discharge hood. A rotating shaft (13) is vertically installed at the center of the interior of the fine crushing unit (2). Both ends of the rotating shaft (13) are supported by bearing seats. 3) Three mounting seats (14) are equidistantly fitted on the upper part. Each mounting seat (14) can be adjusted in height on the rotating shaft (13). Each mounting seat (14) is fixedly equipped with a moving cutter disc (15) on its periphery. Three sets of fixed cutter discs (16) are fixedly installed on the inner wall of the casing of the fine crushing unit (2). The bottom of the casing of the fine crushing unit (2) is provided with a discharge port. A second conveyor (7) is provided below the discharge port. The discharge end of the second conveyor (7) extends obliquely upward and is connected to the input end of the screening and particle size control unit (3).

4. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 3, characterized in that: Both the moving cutter head (15) and the fixed cutter head (16) are made of alloy steel and have replaceable blades embedded around the cutter head. The fixed cutter head (16) and the moving cutter head (15) are arranged alternately. The moving cutter head (15) rotates synchronously at high speed with the rotating shaft (13) to form a crushing chamber between the moving cutter head (15) and the fixed cutter head (16).

5. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: The screening and particle size control unit (3) is internally arranged with a first vibrating screen (17) and a second vibrating screen (18) at a horizontal inclination. Both the first vibrating screen (17) and the second vibrating screen (18) are mounted on shock-absorbing springs (19) built into the side wall of the screening and particle size control unit (3). The first vibrating screen (17) is located above the second vibrating screen (18). A fine powder collection bin (20) is provided at the bottom of the screening and particle size control unit (3). An upper discharge port is opened at a lower position in the inclination direction of the first vibrating screen (17). A third conveyor (8) is provided at the material inlet. A middle layer discharge port is provided at a lower position in the inclined direction of the second vibrating screen (18). A fourth conveyor (9) is provided at the middle layer discharge port. The input ends of the third conveyor (8) and the fourth conveyor (9) are connected to the interior of the screening and particle size control unit (3). The output end of the third conveyor (8) extends obliquely upward and is connected to the feeder (12) on the fine crushing unit (2). The output end of the fourth conveyor (9) extends obliquely upward and is connected to the input end of the magnetic separation unit (4).

6. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 5, characterized in that: The first vibrating screen (17) has a screen hole of 2.0 mm, and the second vibrating screen (18) has a screen hole of 0.5 mm. The material is divided into large material, ideal material and fine material by the first vibrating screen (17) and the second vibrating screen (18). The large material is returned to the fine crushing unit (2) for further crushing by the third conveyor (8). The ideal material enters the magnetic separation unit (4) for sorting by the fourth conveyor (9). The fine material falls directly into the fine powder collection bin (20).

7. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: A vibrating feeder (21) is installed on the top of the magnetic separation unit (4). The discharge end of the fourth conveyor (9) is connected to the input end of the vibrating feeder (21). The output end of the vibrating feeder (21) is connected to the feed inlet of the magnetic separation unit (4). A roller (22) is vertically arranged in the center of the magnetic separation unit (4). A semi-circular strong magnetic block (23) is fixedly installed inside the roller (22). A receiving hopper (25) is arranged below one side of the strong magnetic block (23). A magnetic metal collecting hopper (24) is arranged below the other side of the strong magnetic block (23). A distributor (26) is installed at the bottom of the receiving hopper (25). The distributor (26) is connected to the input end of the high-voltage electrostatic separation unit (5).

8. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: A feeding hopper (27) is provided on the upper left side of the high-voltage electrostatic separation unit (5). The bottom of the receiving hopper (25) is connected to the input end of the feeding hopper (27), and the output end of the feeding hopper (27) is connected to the feed inlet of the high-voltage electrostatic separation unit (5). A metal roller (29) is horizontally arranged at the center of the high-voltage electrostatic separation unit (5). The metal roller (29) is supported by an insulating bearing. A high-voltage ionization electrode wire (30) is arranged on the upper left side of the metal roller (29) and parallel to the axis of the metal roller (29). The high-voltage ionization electrode wire (30) is 30-50mm away from the surface of the metal roller (29) and fixed to the insulating ceramic. On the bottle, an electrostatic induction electrode plate (31) is provided on the right rear side of the metal roller (29). The electrostatic induction electrode plate (31) is arc-shaped and parallel to the axis of the metal roller (29). Below the high-voltage ionization electrode wire (30), a brush (32) is fixed to the inner wall of the high-voltage electrostatic separation unit (5). The brush (32) is in close contact with the surface of the metal roller (29). The bottom of the high-voltage electrostatic separation unit (5) located below the brush (32) is provided with a non-conductive product collection tank (33). The bottom of the high-voltage electrostatic separation unit (5) located below the electrostatic induction electrode plate (31) is provided with a conductive product collection tank (34).

9. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 8, characterized in that: The high-voltage electrostatic sorting unit (5) adopts an insulated protective box structure. All components inside the high-voltage electrostatic sorting unit (5) are encapsulated in the grounded metal box. The box provides mounting points for the bearing seats at both ends of the metal roller (29). A high-voltage power supply box (28) is also installed on the outer wall of the box. The high-voltage ionization electrode wire (30) is connected to the power supply of the high-voltage power supply box (28).

10. The efficient separation and recycling device for valuable metals in waste circuit boards according to claim 1, characterized in that: The first conveyor (6), the second conveyor (7) and the third conveyor (8) are enclosed trough belt conveyors, and the fourth conveyor (9) is a pneumatic conveyor.

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