Method and device for chemically extracting silver from waste crystalline silicon photovoltaic cell

Abstract

The invention relates to the technical field of metal recovery, and discloses a chemical silver extraction method and device for a waste crystalline silicon photovoltaic cell, and the method comprises the following steps: S1, dismounting a cell laminated part, cutting and separating a metal frame and glass, and crushing; s2, the fragments are put into an acid leaching device, and a nitric acid-hydrofluoric acid mixed leaching agent is added; s3, filtering after the reaction to obtain silver-containing filtrate and silicon material residues; and S4, adding a saturated NaCl solution into the silver-containing filtrate to generate white AgCl precipitate, standing, filtering, and collecting the AgCl precipitate. According to the chemical silver extraction method for the waste crystalline silicon photovoltaic cell, through room-temperature one-step synergistic leaching of a nitric acid-hydrofluoric acid compound system, synchronous and efficient dissolution of an aluminum paste layer, etching of silicon nitride and release of silver ions, synchronous extraction of silver and aluminum and protection of a silicon substrate are achieved within a short time, and meanwhile, the chemical silver extraction efficiency of the waste crystalline silicon photovoltaic cell is improved by combining a short-process chlorination silver deposition-zinc powder replacement process. And moreover, the core problems of high energy consumption, low purity and heavy pollution of the traditional process are solved.

Description

Technical Field

[0001] The present invention relates to the technical field of metal recovery, and in particular to a method and device for chemically extracting silver from waste crystalline silicon photovoltaic cells. Background Art

[0002] Crystalline silicon photovoltaic cells contain valuable silver. Efficient silver recovery from retired cells is crucial for achieving resource recycling and economic viability. Current mainstream recovery methods include high-temperature pyrolysis to remove organic matter and then concentrate the silver, and wet leaching with nitric acid or mixed acids to dissolve the metal and then recover it.

[0003] Currently, existing technologies have certain defects in practical application: at the method level, the pyrometallurgical method is extremely energy-intensive, the wet method, although operated at room temperature, has a long reaction time, and often requires separate processing of aluminum and silver, resulting in a lengthy process. At the same time, the leaching process is prone to excessive corrosion of the silicon substrate due to improper control of hydrofluoric acid concentration, resulting in low silicon material recovery rate and reduced purity. Incomplete separation in the silver precipitation step will also affect the silver purity. In addition, at the device level, especially for the core equipment of wet acid leaching, after the acid leaching device completes the reaction, the filter cartridge loaded with solid residue needs to be lifted out of the acid leaching tank as a whole, and then manually opened to discharge the residue. This process not only requires workers to come into close contact with residual acid and wet residue attached with corrosive liquid, which poses a serious safety risk, but also the manual opening and closing of the filter cartridge bottom cover is inefficient, and incomplete residue discharge is prone to residual acid, resulting in a significant increase in water consumption for subsequent rinsing. In addition, frequent lifting, opening, and residue cleaning operations cause long production line interruptions, affecting production efficiency. Summary of the Invention

[0004] The technical problem to be solved by the present invention is that the existing technology has disadvantages such as high energy consumption, lengthy process and insufficient recovery purity. For this reason, we propose a method and device for chemically extracting silver from waste crystalline silicon photovoltaic cells.

[0005] In order to achieve the above-mentioned purpose, the present application adopts the following technical solution: a method for chemically extracting silver from waste crystalline silicon photovoltaic cells, comprising the following steps: S1: Remove the cell laminate, cut and separate the metal frame and glass, and break them; S2: The fragments are placed in an acid leaching device, and a nitric acid-hydrofluoric acid mixed leaching agent is added to dissolve the aluminum paste layer and etch the silicon nitride anti-reflection layer; S3: After the reaction, the silver-containing filtrate and silicon material residue are obtained by filtration. The silicon material is rinsed with deionized water to remove surface acid and impurities, and then dried to obtain high-purity silicon material; S4: adding saturated NaCl solution to the silver-containing filtrate to generate a white AgCl precipitate, allowing it to stand and then filtering to collect the AgCl precipitate; S5: Mix the AgCl precipitate with zinc powder, add dilute sulfuric acid, stir and replace, then filter and wash to obtain sponge-like elemental silver; S6: The waste liquid after silver precipitation is neutralized with lime to neutrality, and the heavy metals are precipitated before discharge in compliance with the standards. The rinsed silicon material is tested for purity and then reused as a metallurgical raw material.

[0006] Preferably, in step S2, the solid-liquid ratio of the fragments to the nitric acid-hydrofluoric acid mixed leaching agent is 1:5, wherein the HNO3 concentration is 10-15%, and the HF concentration is 3-5%.

[0007] Preferably, in step S5, the AgCl precipitate and the zinc powder are mixed in a mass ratio of 1:0.3, and the mass fraction of the dilute sulfuric acid is 10%.

[0008] The present application also includes an embodiment, specifically a chemical silver extraction device for waste crystalline silicon photovoltaic cells, comprising an acid leaching tank and a bracket disposed at the upper end of the acid leaching tank, wherein a filter cartridge is disposed in the acid leaching tank, a lifting frame is disposed at the upper end of the filter cartridge, a first driving source for lifting the lifting frame is disposed at the upper end of the bracket, and a second driving source for driving the filter cartridge to rotate is disposed on the lifting frame; The circumferential side walls of the filter cartridge are evenly provided with openings, and a flip frame is symmetrically rotated at both ends of the inner side of one of the openings, and an arc-shaped filter plate is provided on the inner side of the flip frame and the inner sides of the remaining openings. The flip frame and the filter cartridge are connected by a clamping assembly, and the clamping assembly includes a clamping block movably provided on the inner side of the end of the flip frame, a second elastic member is provided between the clamping block and the inner wall of the end of the flip frame, and a clamping groove corresponding to the clamping block is provided on the inner end of the opening. The clamping block is trapezoidal, and one end thereof is clamped and matched with the clamping groove; An unlocking assembly is provided at the end of the filter cartridge, and the unlocking assembly includes a driving arm movably arranged on the inner side of the end of the filter cartridge and corresponding to the card slot. One end of the driving arm extends to the inner side of the card slot and cooperates with the inclined surface of the card block, and the side wall of the other end is provided with a first force block extending to the outside of the filter cartridge, and the upper end of the bracket is provided with a unloading arm corresponding to the first force block.

[0009] Preferably, the bracket is provided with a receiving mechanism for receiving silicon material residues, and the receiving mechanism includes a fixed frame provided on one side of the bracket and used to support the receiving device, the end of the fixed frame is provided with a second rack plate movably connected to the side of the bracket, and a gear meshing with the second rack plate is rotatably provided on the inner side of the side of the bracket, and the end of the lifting frame is provided with a first rack plate extending to the inner side of the side of the bracket and corresponding to one end of the gear.

[0010] Preferably, a torsion spring is provided at the rotation point between the flip frame and the open end, and the torsion spring is torsionally deformed when the flip frame flips.

[0011] Preferably, a third elastic member is provided at one end of the driving arm away from the locking block, and is configured such that the third elastic member contracts when the driving arm moves toward the locking block.

[0012] Preferably, the acid immersion tank is provided with an acid liquid circulation mechanism, and the acid liquid circulation mechanism includes a flip shaft rotatably arranged at the end of the inner cavity of the acid immersion tank, a second force block is provided on the side wall of one end of the flip shaft, a toggle block corresponding to the second force block is provided on one side of the first force block, a flip plate is provided at the other end of the flip shaft, an arc-shaped piston rod is provided on one side of the flip plate, a nozzle is provided at one end of the inner cavity of the acid immersion tank, a piston cylinder corresponding to the piston rod is provided at the end of the nozzle, one end of the piston cylinder is connected to the nozzle, one end of the piston rod is movably connected to the inside of the piston cylinder, one end of the piston rod is sleeved with a first elastic part, a suction port is provided at the bottom of the nozzle, a nozzle corresponding to the side of the filter cartridge is provided on one side of the upper end of the nozzle, and a one-way valve is provided on both the suction port and the nozzle.

[0013] Preferably, the first elastic member is a spring.

[0014] Preferably, the lifting frame is provided with a through slot corresponding to the unloading arm.

[0015] Technical effects and advantages of the present invention: In the present invention, a one-step synergistic leaching at room temperature of a nitric acid-hydrofluoric acid composite system is used to simultaneously and efficiently dissolve the aluminum slurry layer, etch silicon nitride, and release silver ions, thereby achieving simultaneous leaching of silver and aluminum and protection of the silicon matrix in a relatively short period of time. At the same time, combined with a short-process chloride silver precipitation-zinc powder replacement process, high-purity elemental silver and reusable silicon material are directly obtained. Moreover, the entire leaching waste liquid is closed-loop used for the silver precipitation process, and the terminal wastewater is neutralized and discharged in compliance with the standards, thereby solving the core problems of high energy consumption, low purity, and heavy pollution of traditional processes, and achieving the cost reduction, efficiency improvement, and green and low-carbon goals of resource recycling of retired photovoltaic modules.

[0016] In the present invention, by setting a flip frame in conjunction with the snap-on assembly and the unlocking assembly, the flip frame can be automatically opened when it rises to a certain level after the end, and then combined with the receiving mechanism that is displaced to the bottom of the filter cartridge in advance, the discharge and collection of residues can be automatically realized. When the filter cartridge descends, the receiving mechanism is automatically moved away, which not only improves production efficiency but also has higher safety.

[0017] In the present invention, the acid circulation mechanism is set up to accelerate the acid at the bottom of the acid immersion tank into the filter cartridge according to the rotation of the first force-bearing block, thereby realizing the accelerated flow renewal of the acid, reducing the problem of poor acid flow effect caused by filter plate blockage and improving the reaction effect. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] The disclosure of the present invention is illustrated with reference to the accompanying drawings. It should be understood that the drawings are for illustrative purposes only and are not intended to limit the scope of protection of the present invention. In the drawings, the same reference numerals are used to refer to the same components: Figure 1 It is a schematic diagram of the method flow structure of the present invention; Figure 2It is a structural schematic diagram of the acid leaching device of the present invention; Figure 3 This is a structural diagram of the acid leaching device support, acid leaching tank, and filter cartridge of the present invention in a disassembled state; Figure 4 This is a structural diagram of the present invention when the receiving mechanism and the filter cartridge are in a coordinated state; Figure 5 This is a structural diagram of the present invention with the lifting frame and filter cartridge disassembled; Figure 6 This is a structural diagram of the present invention with the flip frame and filter cartridge disassembled; Figure 7 This is a schematic structural diagram of the present invention with the flip frame end and the open end disassembled; Figure 8 It is a schematic cross-sectional view of the flip frame of the present invention in a state of being engaged with the open end; Figure 9 This is a schematic structural diagram of the present invention with the drive arm and filter cartridge end portion disassembled; Figure 10 It is a schematic structural diagram of the interior of the acid leaching tank of the present invention.

[0019] Legend: 1. Bracket; 2. Acid immersion tank; 3. Screw; 4. First drive motor; 5. Discharge arm; 6. Filter cartridge; 7. Linear guide; 8. First rack plate; 9. Fixed frame; 10. Filter plate; 11. Second rack plate; 12. Gear; 13. Second drive motor; 14. Sprocket; 15. Chain; 16. Opening; 17. Turning frame; 18. First force block; 19. Toggle block; 20. Drive arm; 21. Block; 22. Torsion spring; 23. First elastic member; 24. Second elastic member; 25. Slot; 26. Piston rod; 27. Guide pin; 28. Third elastic member; 29. ​​Turning shaft; 30. Second force block; 31. Turning plate; 32. Piston cylinder; 33. Nozzle; 34. Nozzle; 35. Suction port; 36. Lifting frame. DETAILED DESCRIPTION

[0020] It is easy to understand that according to the technical solution of the present invention, without changing the essential spirit of the present invention, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific embodiments and drawings are only exemplary descriptions of the technical solution of the present invention and should not be regarded as the entire invention or as a limitation or restriction of the technical solution of the present invention.

[0021] Reference Figure 1 As shown, a method for chemically extracting silver from waste crystalline silicon photovoltaic cells comprises the following steps: Step 1: Manually remove the cell EVA / back sheet, use a glass cutter and cell crusher to separate the metal frame and glass and break them into pieces, preferably 5×5 cm 2 fragments; Step 2: Place the fragments into an acid leaching device, add a nitric acid-hydrofluoric acid mixed leaching agent at a solid-liquid ratio of 1:5, wherein the HNO3 concentration is 10-15%, and the HF concentration is 3-5%. Soak and rotate at room temperature of 25±5℃ for 60-90 minutes to dissolve the aluminum slurry layer and etch the silicon nitride anti-reflection layer. During this period, the exhaust gas is passed into an acid mist absorption tower for treatment; Step 3: After the reaction, the mixture is filtered to obtain a silver-containing filtrate and silicon material residue. The silicon material is rinsed three times with deionized water to remove surface acid and impurities, and then dried to obtain high-purity silicon material. Step 4: Slowly add saturated NaCl solution to the silver-containing filtrate to generate white AgCl precipitate, and control Cl ⁻ Add 10% excess, let it stand for 30 minutes and then filter to collect the AgCl precipitate. This step can be achieved by using a precipitation reaction tank and a plate and frame filter press; Step 5: Mix the AgCl precipitate and zinc powder in a mass ratio of 1:0.3, add 10% dilute sulfuric acid, stir and replace for 30 minutes, the reaction formula is: 2AgCl+Zn→2Ag+ZnCl2, then filter and wash to obtain sponge-like elemental silver; Step 6: The post-silver waste liquid is neutralized with lime to neutrality, and the heavy metals are precipitated before discharge in compliance with the standards. The rinsed silicon material is tested for purity by a silicon material component analyzer and then reused as a metallurgical raw material.

[0022] This method uses nitric acid to dissolve silver / aluminum and hydrofluoric acid to etch silicon nitride. It operates at room temperature and saves energy. Moreover, silver is extracted through three steps of acid leaching → silver precipitation → replacement, avoiding high-energy consumption steps such as traditional roasting. Secondly, all the acid leaching waste liquid is used for silver precipitation and is discharged in compliance with standards after neutralization, solving the pollution problem. The silicon material after rinsing has a high silicon content and can be directly used for metallurgy or silicon smelting.

[0023] like Figure 2-Figure 10 As shown, the present application also includes an embodiment, specifically a device for chemically extracting silver from waste crystalline silicon photovoltaic cells, which is applied to the above-mentioned method for chemically extracting silver from waste crystalline silicon photovoltaic cells, specifically the acid leaching device in step 2; Specifically, such as Figure 2-Figure 8As shown, the device includes an acid leaching tank 2 and a bracket 1 arranged at the upper end of the acid leaching tank 2, a filter cartridge 6 is arranged in the acid leaching tank 2, and the circumferential side walls of the filter cartridge 6 are evenly provided with openings 16, and the two ends of the inner side of one of the openings 16 are symmetrically rotated with a flip frame 17, and the inner side of the flip frame 17 and the inner sides of the other openings 16 are provided with an arc-shaped filter plate 10, and a lifting frame 36 is provided on the upper end of the filter cartridge 6, and a screw 3 is rotatably provided on the upper end of the bracket 1, and a first drive motor 4 for driving the screw 3 to rotate is provided on the top of the bracket 1, and the upper end of the lifting frame 36 is threadedly matched with the screw 3, so that the screw 3 rotates the lifting frame 36 to drive the filter cartridge 6 to rise and fall, and the two ends of the filter cartridge 6 are provided with a rotating shaft that rotates with the side of the lower end of the lifting frame 36, and the lower end of the lifting frame 36 A pair of sprockets 14 are rotatably provided on one side of the filter cartridge 6, and a chain 15 is meshed together on the two sprockets 14. The rotating shaft at one end of the filter cartridge 6 is fixed to the middle of the sprocket 14 at the lower end. A second drive motor 13 is provided on the outside of the lifting frame 36 for driving the sprocket 14 at the upper end to rotate. In order to facilitate loading and unloading, the flip frame 17 and the filter cartridge 6 are connected through a clamping assembly. As a preferred embodiment, the clamping assembly includes a clamping block 21 movably provided on the inner side of the end of the flip frame 17, and a second elastic member 24 is provided between the clamping block 21 and the inner wall of the end of the flip frame 17. The second elastic member 24 is preferably a spring. The inner end of the opening 16 is provided with a clamping groove 25 corresponding to the clamping block 21. The clamping block 21 is trapezoidal, and one end thereof is clamped and matched with the clamping groove 25. Further, such as Figure 2 、 Figure 6-Figure 9 As shown, in order to realize the automatic opening of the flip frame 17 when rising, an unlocking component is provided at the end of the filter cartridge 6. As a preferred embodiment, the unlocking component includes a driving arm 20 movably arranged on the inner side of the end of the filter cartridge 6 and corresponding to the card slot 25. One end of the driving arm 20 extends to the inner side of the card slot 25 and cooperates with the inclined surface of one end of the card block 21, and the lower end of the driving arm 20 can completely squeeze out the end of the card block 21 located inside the card slot 25. The side wall of the other end of the driving arm 20 is provided with a first force block 18 extending to the outside of the filter cartridge 6. The upper end of the bracket 1 is provided with a discharge arm 5 corresponding to the first force block 18. The lifting frame 36 is provided with a through groove corresponding to the discharge arm 5. When the filter cartridge 6 rises, the lower end of the discharge arm 5 can pass through The filter cartridge 6 contacts the first force block 18 through the through groove. In order to facilitate the resetting of the driving arm 20, a guide pin 27 corresponding to one end of the driving arm 20 is provided on the inner side of the end of the filter cartridge 6. The cross-section of the guide pin 27 is "T"-shaped. The end of the driving arm 20 away from the block 21 is movably connected to the guide pin 27, and one end of the guide pin 27 is provided with a third elastic member 28. The third elastic member 28 is preferably a spring, which is configured as follows: when the driving arm 20 moves toward the block 21, the third elastic member 28 contracts. In order to increase the stability of the flip frame 17 and improve the opening efficiency of the flip frame 17, a torsion spring 22 is provided at the rotation point between the flip frame 17 and the end of the opening 16. When the flip frame 17 flips, the torsion spring 22 is torsionally deformed.

[0024] like Figure 2-Figure 3 As shown, in order to move the receiving device to the bottom of the filter cartridge 6 before the flip frame 17 is opened, a receiving mechanism for receiving silicon material residue is provided on the bracket 1. The receiving mechanism includes a fixing frame 9 provided on one side of the bracket 1 and used to support the receiving device. The end of the fixing frame 9 is provided with a second rack plate 11 movably connected to the side of the bracket 1. In order to increase the stability of the second rack plate 11 and the fixing frame 9, a linear guide rail 7 for supporting the second rack plate 11 is provided on the side of the bracket 1. The second rack plate 11 is connected to the second rack plate 11. The linear guide rail 7 is movably guided and cooperated, and a gear 12 meshing with the top of the second rack plate 11 is rotatably provided on the inner side of the side of the bracket 1. The end of the lifting frame 36 is provided with a first rack plate 8 extending to the inner side of the side of the bracket 1 and corresponding to one end of the gear 12. The configuration is: when the filter cartridge 6 is higher than the fixed frame 9, the first rack plate 8 is engaged with the gear 12; when the fixed frame 9 is located directly below the filter cartridge 6, the first rack plate 8 is separated from the gear 12; and after the first rack plate 8 is separated from the gear 12, the unloading arm 5 contacts the first force block 18.

[0025] In addition, if Figure 6 、 Figure 9-10 As shown, in order to increase the flow effect of the acid in the acid leaching tank 2, an acid circulation mechanism is provided in the acid leaching tank 2, and the acid circulation mechanism includes a flip shaft 29 rotatably arranged at the end of the inner cavity of the acid leaching tank 2, and a second force block 30 is provided on the side wall of one end of the flip shaft 29, and a toggle block 19 corresponding to the second force block 30 is provided on one side of the first force block 18, and is configured as follows: when the filter cartridge 6 is located in the inner cavity of the acid leaching tank 2 and rotates, the toggle block 19 can touch the second force block 30; a flip plate 31 is provided at the other end of the flip shaft 29, and an arc-shaped piston rod 26 is provided on one side of the flip plate 31, and a nozzle 33 is provided at one end of the inner cavity of the acid leaching tank 2, and a piston cylinder 32 corresponding to the piston rod 26 is provided at the end of the nozzle 33, and one end of the piston cylinder 32 is connected to the nozzle 33 The first elastic member 23 is preferably a spring, which can be reset after the piston rod 26 is displaced in the direction of the piston cylinder 32. A plurality of suction ports 35 for sucking acid liquid are provided at the bottom of the nozzle 33, and a nozzle 34 corresponding to the side of the filter cartridge 6 is provided on one side of the upper end of the nozzle 33, and a one-way valve is provided on both the suction port 35 and the nozzle 34. The one-way valve on the suction port 35 only allows the acid liquid in the inner cavity of the acid leaching tank 2 to enter the nozzle 33 from the suction port 35, and the one-way valve on the nozzle 34 only allows the acid liquid in the nozzle 33 to be ejected from the nozzle 34, thereby realizing the transfer of the acid liquid at the bottom of the acid leaching tank 2 to the inside of the filter cartridge 6, thereby improving the fluidity of the acid liquid.

[0026] The specific working principle of the chemical silver extraction device for waste crystalline silicon photovoltaic cells: when in use, in the initial state, the filter cartridge 6 is located at the upper end of the acid leaching tank 2, and the opening 16 corresponding to the flip frame 17 is facing upward or sideways, and the broken photovoltaic cell fragments are added into the inner cavity of the filter cartridge 6 through the opening 16 corresponding to the flip frame 17, and then the flip frame 17 is flipped and closed, and the inclined surface of one end of the block 21 is pressed and displaced, and the second elastic member 24 is compressed. When the block 21 is matched with the slot 25, the second elastic member 24 is reset, and one end of the block 21 is stuck in the inner cavity of the slot 25, and then the first drive motor 4 is controlled to drive the screw 3 to rotate, and the screw 3 drives the filter cartridge 6 to move downward through the lifting frame 36, and a nitric acid-hydrofluoric acid mixed leaching agent is added to the acid leaching tank 2, and the filter cartridge 6 enters In the leaching agent, the second driving motor 13 is controlled to cooperate with the sprocket 14 and the chain 15 to realize the slow rotation of the filter cartridge 6. During the rotation, the toggle block 19 on the side of the first force-bearing block 18 will touch the second force-bearing block 30, and then the second force-bearing block 30 drives the flip shaft 29, the flip plate 31, and the piston rod 26 to flip a certain amplitude as a whole, and then the first elastic member 23 contracts, and the piston rod 26 squeezes the piston cylinder 32 and the inner cavity of the nozzle 33, and the acid in the inner cavity of the nozzle 33 can be squeezed out from the nozzle 34, and then the squeezed acid is blown to the filter plate 10 on the surface of the filter cartridge 6, and enters the inner cavity of the filter cartridge 6 through the filter plate, realizing the accelerated flow of the acid, and placing or fixing a receiving device on the fixing frame 9 in advance, such as a receiving tank or other receiving device. After the end, the flip The frame 17 rotates to stop just below the filter cartridge 6, and then the filter cartridge 6 is lifted up again by rotating the screw 3. The first rack plate 8 will rise with the lifting frame 36. When the filter cartridge 6 is higher than the fixing frame 9, the first rack plate 8 begins to mesh with the gear 12, and then the gear 12 drives the fixing frame 9 to translate through the second rack plate 11. When the fixing frame 9 is just below the filter cartridge 6, the first rack plate 8 separates from the gear 12, and the fixing frame 9 stops. Subsequently, the unloading arm 5 passes through the through slot on the lifting frame 36 and comes into contact with the first force block 18, thereby pushing the first force block 18 and the driving arm 20 to move as a whole. The third elastic member 28 contracts, and one end of the driving arm 20 is displaced by squeezing the card block 21 through the inclined surface, and then one end of the card block 21 is released from the card The groove 25 is disengaged, and the flip frame 17 is flipped upward and opened under the joint action of the flip frame 17, the filter plate 10 and the dead weight of the residue and the reset force of the torsion spring 22, and the residue inside the filter cartridge 6 falls into the receiving device on the top of the fixed frame 9, and then the acid in the pickling tank 2 is discharged, and the filter cartridge 6 and the pickling tank 2 are cleaned as needed. During subsequent use, the screw 3 first drives the filter cartridge 6 to move down a distance, so that the unloading arm 5 is separated from the first force block 18, and the second drive motor 13 is controlled to drive the filter cartridge 6 to rotate a certain amplitude, so that the opening 16 corresponding to the flip frame 17 is located on the side or upward, which is convenient for feeding. Then the flip frame 17 is closed, and the filter cartridge 6 is continued to be controlled to move down. The fixed frame 9 is removed, and the filter cartridge 6 enters the inner cavity of the pickling tank 2 again, and the cycle is repeated.

[0027] The technical scope of the present invention is not limited to the contents of the above description. Those skilled in the art can make various deformations and modifications to the above embodiments without departing from the technical idea of ​​the present invention, and these deformations and modifications should all fall within the protection scope of the present invention.

Claims

1. A method for chemically extracting silver from waste crystalline silicon photovoltaic cells, characterized in that: The following steps are involved: S1: Remove the cell laminate, cut and separate the metal frame and glass, and break them; S2: The fragments are placed in an acid leaching device, and a nitric acid-hydrofluoric acid mixed leaching agent is added to dissolve the aluminum paste layer and etch the silicon nitride anti-reflection layer; S3: After the reaction, the silver-containing filtrate and silicon material residue are obtained by filtration. The silicon material is rinsed with deionized water to remove surface acid and impurities, and then dried to obtain high-purity silicon material; S4: adding saturated NaCl solution to the silver-containing filtrate to generate a white AgCl precipitate, allowing it to stand and then filtering to collect the AgCl precipitate; S5: Mix the AgCl precipitate with zinc powder, add dilute sulfuric acid, stir and replace, then filter and wash to obtain sponge-like elemental silver; S6: The waste liquid after silver precipitation is neutralized with lime to neutrality, and the heavy metals are precipitated before discharge in compliance with the standards. The rinsed silicon material is tested for purity and then reused as a metallurgical raw material.

2. The method for chemically extracting silver from waste crystalline silicon photovoltaic cells according to claim 1, characterized in that: In step S2, the solid-liquid ratio of the fragments to the nitric acid-hydrofluoric acid mixed leaching agent is 1:5, wherein the HNO3 concentration is 10-15%, and the HF concentration is 3-5%.

3. The method for chemically extracting silver from waste crystalline silicon photovoltaic cells according to claim 1, characterized in that: In step S5, AgCl precipitate and zinc powder are mixed in a mass ratio of 1:0.3, and the mass fraction of dilute sulfuric acid is 10%.

4. A device for chemically extracting silver from waste crystalline silicon photovoltaic cells, applied to the method for chemically extracting silver from waste crystalline silicon photovoltaic cells according to any one of claims 1 to 3, characterized in that: The invention comprises an acid leaching tank and a bracket arranged at the upper end of the acid leaching tank, wherein a filter cartridge is arranged in the acid leaching tank, a lifting frame is arranged at the upper end of the filter cartridge, a first driving source for lifting the lifting frame is arranged at the upper end of the bracket, and a second driving source for driving the filter cartridge to rotate is arranged on the lifting frame; The circumferential side walls of the filter cartridge are evenly provided with openings, and a flip frame is symmetrically rotated at both ends of the inner side of one of the openings, and an arc-shaped filter plate is provided on the inner side of the flip frame and the inner sides of the remaining openings. The flip frame and the filter cartridge are connected by a clamping assembly, and the clamping assembly includes a clamping block movably provided on the inner side of the end of the flip frame, a second elastic member is provided between the clamping block and the inner wall of the end of the flip frame, and a clamping groove corresponding to the clamping block is provided on the inner end of the opening. The clamping block is trapezoidal, and one end thereof is clamped and matched with the clamping groove; An unlocking assembly is provided at the end of the filter cartridge, and the unlocking assembly includes a driving arm movably arranged on the inner side of the end of the filter cartridge and corresponding to the card slot. One end of the driving arm extends to the inner side of the card slot and cooperates with the inclined surface of the card block, and the side wall of the other end is provided with a first force block extending to the outside of the filter cartridge, and the upper end of the bracket is provided with a unloading arm corresponding to the first force block.

5. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 4, characterized in that: The bracket is provided with a receiving mechanism for receiving silicon material residues, and the receiving mechanism includes a fixed frame provided on one side of the bracket and used to support the receiving device, the end of the fixed frame is provided with a second rack plate movably connected to the side of the bracket, the inner side of the bracket is rotatably provided with a gear meshing with the second rack plate, and the end of the lifting frame is provided with a first rack plate extending to the inner side of the bracket and corresponding to one end of the gear.

6. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 4, characterized in that: A torsion spring is provided at the rotation point between the flip frame and the open end portion, and the torsion spring is torsionally deformed when the flip frame flips.

7. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 4, characterized in that: A third elastic member is provided at one end of the driving arm away from the locking block, and is configured such that: when the driving arm moves toward the locking block, the third elastic member contracts.

8. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 4, characterized in that: The acid leaching tank is provided with an acid liquid circulation mechanism, which includes a flip shaft rotatably arranged at the end of the inner cavity of the acid leaching tank, a second force-bearing block is provided on the side wall of one end of the flip shaft, a toggle block corresponding to the second force-bearing block is provided on one side of the first force-bearing block, a flip plate is provided at the other end of the flip shaft, an arc-shaped piston rod is provided on one side of the flip plate, a nozzle is provided at one end of the inner cavity of the acid leaching tank, a piston cylinder corresponding to the piston rod is provided at the end of the nozzle, one end of the piston cylinder is connected to the nozzle, one end of the piston rod is movably connected to the inside of the piston cylinder, one end of the piston rod is sleeved with a first elastic member, a suction port is provided at the bottom of the nozzle, a nozzle corresponding to the side of the filter cartridge is provided on one side of the upper end of the nozzle, and a one-way valve is provided on both the suction port and the nozzle.

9. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 8, characterized in that: The first elastic member is a spring.

10. The chemical silver extraction device for waste crystalline silicon photovoltaic cells according to claim 4, characterized in that: The lifting frame is provided with a through slot corresponding to the unloading arm.

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