Method for separating and extracting metal elements in retired photovoltaic cell and application

Abstract

The invention discloses a method for separating and extracting metal elements in an out-of-service photovoltaic cell and application, and the method comprises the following steps: carrying out vacuum liquefaction treatment on solder powder of the out-of-service photovoltaic cell to obtain a silver-rich material and a lead-tin-rich material; the silver-rich material and a carbonizable organic precursor are mixed to obtain a mixed material, the mixed material and the lead-tin-rich material are heated and then subjected to first vacuum gasification treatment, and lead, primary tin and a secondary silver-rich material are obtained; the secondary silver-rich material is subjected to second vacuum gasification treatment, and secondary tin and a third silver-rich material are obtained; and the third-time silver-rich material is subjected to third vacuum gasification treatment, and silver is obtained. According to the method, the metal extraction rate is high, the extracted metal purity is high, the recovery rates of lead, tin and silver are all larger than or equal to 95.0%, the purity is all larger than or equal to 98.5%, the method has the advantages of being simple in process, environmentally friendly, efficient and low in cost, and the technical bottleneck of efficient separation of high-value metal in a solder enrichment area is solved.

Description

Technical Field

[0001] This invention relates to the field of secondary resource regeneration technology for photovoltaic devices, and in particular to a method and application for separating and extracting metal elements from retired photovoltaic cells. Background Technology

[0002] As people become more environmentally conscious, the demand for renewable energy is also increasing. Photovoltaic (PV) devices, as a clean energy technology, can reduce dependence on fossil fuels and greenhouse gas emissions, and have therefore received widespread attention and support. However, with the demands of their service life, a large number of PV devices will be decommissioned. To date, there is no large-scale solar panel scrapping technology. If this situation is not changed, by 2050, 78 million tons of PV waste will be discarded. If discarded PV devices are not properly handled, they may pose safety hazards, such as risks to workers and the surrounding environment during dismantling, transportation, and disposal.

[0003] Addressing the impending photovoltaic waste crisis is a pressing issue. Photovoltaic devices contain a large amount of rare metals and other raw materials, primarily valuable metals such as copper, aluminum, lead, tin, and silver. Materials in the solder enrichment area can be obtained through the dismantling, separation, and enrichment of retired photovoltaic modules using conventional techniques. However, the solder connection areas between cells are mainly composed of lead, tin, and silver. These three metals are tightly bound to silicon-based impurities, making efficient separation difficult using traditional physical sorting or chemical leaching processes. This often results in low metal recovery rates, insufficient purity, or secondary pollution, becoming a core technological bottleneck for the regeneration of photovoltaic panel metal resources. Summary of the Invention

[0004] This invention aims to address the problem of low metal content and difficulty in extracting high-value metals from the solder-rich areas of decommissioned photovoltaic devices. It proposes an efficient, environmentally friendly, and clean recycling technology that utilizes a vacuum liquefaction-gasification separation technique based on the nano-confinement effect to extract high-value metals from the solder-rich areas of decommissioned photovoltaic devices, thereby achieving the goal of waste utilization.

[0005] To achieve the above objectives, the present invention provides a method for separating and extracting metal elements from decommissioned photovoltaic cells, comprising, The solder powder from retired photovoltaic cells is liquefied under vacuum to obtain silver-rich and lead-tin-rich materials. The silver-rich material is mixed with a carbonizable organic precursor to obtain a mixture. The mixture is then heated with a lead- and tin-rich material and subjected to a first vacuum vaporization treatment to obtain lead, primary tin, and secondary silver-rich materials. The secondary silver-rich material is subjected to a second vacuum gasification treatment to obtain secondary tin and tertiary silver-rich material. Silver is obtained by subjecting the three silver-rich materials to a third vacuum gasification treatment.

[0006] Furthermore, the carbonizable organic precursor includes at least one of citric acid, glucose, sucrose, polyethylene glycol, and polyvinylpyrrolidone, accounting for 0.5%-2% of the silver-rich material.

[0007] Furthermore, the particle size of the carbonizable organic precursor is 0.1-0.3 mm.

[0008] Furthermore, the vacuum liquefaction process is carried out under a vacuum of 50-100 Pa and a temperature of 450-500 °C for 1-2 hours.

[0009] Furthermore, the temperature is increased to 350-450℃ at a rate of 3-8℃ / min and held at that temperature for 0.5-2h; The first vacuum gasification treatment is carried out at a vacuum degree of 1-10 Pa and a temperature of 700-800℃ for 1-2 hours.

[0010] Furthermore, the second vacuum gasification treatment is carried out at a vacuum degree of 1-10 Pa and a temperature of 1100-1200℃ for 1-2 hours.

[0011] Furthermore, the third vacuum gasification treatment is carried out at a vacuum degree of 1-10 Pa and a temperature of 1300-1400℃ for 3-4 hours.

[0012] Furthermore, the collection of lead, tin, and silver is achieved through condensation at temperatures of 100-250°C.

[0013] Furthermore, the solder powder of the retired photovoltaic cells is obtained by crushing, grinding, sieving, and physically sorting the solder of the retired photovoltaic cells to remove copper, silicon, and residual encapsulation material fragments; The solder powder of the retired photovoltaic cells has a particle size of 0.1-0.5mm, and contains a total mass percentage of lead, tin and silver of not less than 85%, and a total mass percentage of aluminum and copper of less than 5%.

[0014] This invention also provides the application of the above-described method for separating and extracting metal elements from decommissioned photovoltaic cells in the treatment of decommissioned photovoltaic devices.

[0015] Compared with the prior art, the present invention has the following beneficial effects: This invention utilizes a carbonizable organic precursor, which, after low-temperature pyrolysis and carbonization, forms a nano-confined network on the surface and in the gaps of a tin-silver alloy. The resulting nano-carbon layer adds abundant defects and active sites to the entire system. The carbon layer has a stronger affinity for tin and easily migrates from the alloy system to the carbon layer interface, effectively reducing the energy barrier for tin-silver alloy reconstruction and relaxation. Due to the nano-confined effect, the carbon layer catalyzes the volatilization of tin, while the carbon layer's coating effect on silver inhibits the synergistic volatilization of tin and silver. This facilitates the efficient separation of tin and silver, promoting the preferential volatilization of tin atoms and inhibiting the volatilization of silver atoms. Ultimately, the tin-silver atoms are volatilized and discharged at high temperatures, thus achieving the catalytic tin-silver dissociation process.

[0016] This invention replaces the high-temperature vacuum liquefaction process with a lower-temperature vacuum liquefaction process, reducing the amount of material requiring high-temperature processing and thus significantly reducing the overall process energy consumption. The low-temperature liquefaction step allows most of the lead and tin in the raw material to be separated in a low-energy manner. The separation of the two metals can be completed in just one step of vaporization for the lead-tin alloy, which reduces operating costs compared to adopting a full-process distillation process, thereby enhancing the high efficiency and energy-saving advantages of this process.

[0017] This invention features high metal extraction rates and high purity, with lead, tin, and silver recovery rates all ≥95.0% and purity all ≥98.5%. It boasts advantages such as simple process, green efficiency, and low cost, solving the technical bottleneck of efficient separation of high-value metals from solder-rich areas. Furthermore, the process suppresses the generation of harmful gases and does not release any toxic or harmful substances into the environment, exhibiting high efficiency, environmental friendliness, and high resource utilization, making it suitable for large-scale industrial applications. It provides an economically and environmentally valuable solution for metal extraction from photovoltaic devices. Attached Figure Description

[0018] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0019] Figure 1 A flowchart of the method for separating and extracting metal elements from decommissioned photovoltaic cells according to the present invention is shown; Figure 2 A schematic diagram of the stepped graphite crucible used in this invention is shown. Figure 3 A schematic diagram of the vacuum distillation furnace used in this invention is shown. Detailed Implementation

[0020] The endpoints and any values ​​of the ranges disclosed in this invention are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this invention.

[0021] The technical solutions of the present invention will be clearly and completely described below with reference to specific embodiments and 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.

[0022] Example 1 A method for separating and extracting metal elements from decommissioned photovoltaic cells includes the following steps: S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0023] S2. Place the solder powder from the retired photovoltaic cells in a container such as... Figure 2 In the stepped graphite crucible shown, the uppermost layer is the melting zone, and the two layers below are the collection zones. It is then transferred to... Figure 3 The vacuum distillation furnace shown comprises a tubular furnace, a condenser, a filter, and a vacuum pump connected in sequence. N2 is introduced into the tubular furnace and a vacuum of 50 Pa is created. The temperature is then increased to 480°C at a rate of 10°C / min and held for 1.5 hours. This low-temperature vacuum liquefaction process significantly reduces the amount of material requiring the highest temperature treatment and the high-temperature operating time, thereby substantially reducing the overall process energy consumption. Silver-rich and lead-tin-rich materials are obtained in the melting and collection zones, respectively.

[0024] S3. Add 1 wt% citric acid (0.1 mm particle size) to the silver-rich material and grind it in a mortar until the particles are fully mixed to obtain a mixture. Place the mixture and the lead-tin-rich material in a first crucible and a second crucible, respectively, and then place them side by side in the heating zone of a tube furnace. The first and second crucibles are standard graphite crucibles. Introduce N2 into the tube furnace and evacuate it to 100 Pa. Increase the temperature to 400°C at 5°C / min and hold for 1 hour to achieve carbonization of the citric acid through the heating process.

[0025] S4. Evacuate the vacuum distillation furnace to 1 Pa, and heat it to 750°C at 10°C / min. Hold the temperature for 2 hours. Collect lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0026] S5. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1200°C at 5°C / min and hold for 2 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0027] S6. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1400℃ at 5℃ / min and hold for 4 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0028] Example 2 A method for separating and extracting metal elements from decommissioned photovoltaic cells includes the following steps: S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0029] S2. The solder powder from the retired photovoltaic cells is placed in a stepped graphite crucible. It is then transferred to a tube furnace in a vacuum distillation furnace. N2 is introduced into the tube furnace and a vacuum of 50 Pa is created. The temperature is increased to 400°C at a rate of 10°C / min and held for 1 hour. Silver-rich and lead-tin-rich materials are obtained in the melting and collection zones, respectively.

[0030] S3. Add 1 wt% citric acid (0.1 mm particle size) to the silver-rich material and grind it in a mortar until the particles are fully mixed to obtain a mixture. Place the mixture and the lead-tin-rich material in a first crucible and a second crucible, respectively, and then place them side by side in the heating zone of a tube furnace. The first and second crucibles are standard graphite crucibles. Introduce N2 into the tube furnace and evacuate it to 100 Pa. Increase the temperature to 400°C at 5°C / min and hold for 1 hour to achieve carbonization of the citric acid through the heating process.

[0031] S4. Evacuate the vacuum distillation furnace to 1 Pa, and heat it to 750°C at 10°C / min. Hold the temperature for 2 hours. Collect lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0032] S5. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1200°C at 5°C / min and hold for 2 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0033] S6. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1400℃ at 5℃ / min and hold for 4 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0034] Example 3 A method for separating and extracting metal elements from decommissioned photovoltaic cells includes the following steps: S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0035] S2. The solder powder from the retired photovoltaic cells is placed in a stepped graphite crucible. It is then transferred to a tube furnace within a vacuum distillation furnace. N2 is introduced into the tube furnace, and a vacuum of 50 Pa is created. The temperature is increased to 480°C at a rate of 10°C / min and held for 1.5 hours. Silver-rich and lead-tin-rich materials are obtained in the melting and collection zones, respectively.

[0036] S3. Add 1 wt% PEG-400 (0.1 mm particle size) to the silver-rich material and grind it in a mortar until the particles are fully mixed to obtain a mixture. Place the mixture and the lead-tin-rich material in the first crucible and the second crucible, respectively, and then place them side by side in the heating zone of a tube furnace. Introduce N2 into the tube furnace and evacuate to 100 Pa. Increase the temperature to 400°C at 5°C / min and hold for 1 hour to achieve carbonization of citric acid through the heating process.

[0037] S4. Evacuate the vacuum distillation furnace to 1 Pa, and heat it to 750°C at 10°C / min. Hold the temperature for 2 hours. Collect lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0038] S5. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1200°C at 5°C / min and hold for 2 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0039] S6. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1400℃ at 5℃ / min and hold for 4 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0040] Example 4 A method for separating and extracting metal elements from decommissioned photovoltaic cells includes the following steps: S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0041] S2. The solder powder from the retired photovoltaic cells is placed in a stepped graphite crucible. It is then transferred to a tube furnace within a vacuum distillation furnace. N2 is introduced into the tube furnace, and a vacuum of 50 Pa is created. The temperature is increased to 480°C at a rate of 10°C / min and held for 1.5 hours. Silver-rich and lead-tin-rich materials are obtained in the melting and collection zones, respectively.

[0042] S3. Add 1 wt% citric acid (0.1 mm particle size) to the silver-rich material and grind it in a mortar until the particles are fully mixed to obtain a mixture. Place the mixture and the lead-tin-rich material in the first crucible and the second crucible, respectively, and then place them side by side in the heating zone of a tube furnace. Introduce N2 into the tube furnace and evacuate it to 100 Pa. Increase the temperature to 400°C at 5°C / min and hold for 1 hour to achieve carbonization of the citric acid through the heating process.

[0043] S4. Evacuate the vacuum distillation furnace to 1 Pa, and heat it to 800°C at 10°C / min. Hold the temperature for 2.5 hours. Collect lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0044] S5. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1150°C at 5°C / min and hold for 1.5 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0045] S6. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1400℃ at 5℃ / min and hold for 4 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0046] Example 5 A method for separating and extracting metal elements from decommissioned photovoltaic cells includes the following steps: S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0047] S2. The solder powder from the retired photovoltaic cells is placed in a stepped graphite crucible. It is then transferred to a tube furnace within a vacuum distillation furnace. N2 is introduced into the tube furnace, and a vacuum of 50 Pa is created. The temperature is increased to 480°C at a rate of 10°C / min and held for 1.5 hours. Silver-rich and lead-tin-rich materials are obtained in the melting and collection zones, respectively.

[0048] S3. Add 1 wt% citric acid (0.1 mm particle size) to the silver-rich material and grind it in a mortar until the particles are fully mixed to obtain a mixture. Place the mixture and the lead-tin-rich material in the first crucible and the second crucible, respectively, and then place them side by side in the heating zone of a tube furnace. Introduce N2 into the tube furnace and evacuate it to 100 Pa. Increase the temperature to 400°C at 5°C / min and hold for 1 hour to achieve carbonization of the citric acid through the heating process.

[0049] S4. Evacuate the vacuum distillation furnace to 1 Pa, and heat it to 750°C at 10°C / min. Hold the temperature for 2 hours. Collect lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0050] S5. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1200°C at 5°C / min and hold for 2 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0051] S6. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1300℃ at 5℃ / min and hold for 3 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0052] Comparative Example 1 S1. Taking the solder-rich area of ​​the interconnection region of retired crystalline silicon photovoltaic module cells as the processing target, the cells are crushed, ground, and sieved, and copper, silicon and residual encapsulation material fragments are removed by physical sorting to obtain solder powder of retired photovoltaic cells with a particle size of 0.1mm.

[0053] S2. The solder powder from the retired photovoltaic cells was placed in a stepped graphite crucible and then transferred to a tube furnace of a vacuum distillation furnace. N2 was introduced into the tube furnace and a vacuum of 50 Pa was created. The temperature was increased to 480°C at 10°C / min and held for 1.5 hours. Silver-rich materials and lead-tin-rich materials were obtained in the melting zone and collection zone, respectively.

[0054] S3. Place the silver-rich material and the lead-tin-rich material into the first crucible and the second crucible respectively, and then place them side by side in the heating area of ​​the tube furnace. Evacuate the pressure in the vacuum distillation furnace to 1 Pa, and heat it to 750°C at 10°C / min and hold it for 2 hours. Collect the lead ingots on the condensing surface of the condenser, remove the second crucible, and collect the remaining tin ingots.

[0055] S4. Introduce N2 into the vacuum distillation furnace and evacuate to 1 Pa. Then, raise the temperature to 1200°C at 5°C / min and hold for 2 hours to vaporize the tin in the first crucible. Collect the tin ingots on the condensing surface of the condenser.

[0056] S5. Introduce N2 into the vacuum distillation furnace and evacuate it to 1 Pa. Then, raise the temperature to 1400℃ at 5℃ / min and hold it for 4 hours to vaporize the silver in the first crucible. Collect the silver ingots on the condensing surface of the condenser.

[0057] The purity and recovery rate of the metals collected in the above embodiments and comparative examples are shown in Table 1.

[0058] Table 1. Results of metal purity and recovery rate

[0059] The results show that, compared to Example 1, the vacuum liquefaction temperature in Example 2 was reduced from 480℃ to 400℃, and the holding time was reduced from 1.5h to 1h. Due to the lower temperature, liquefaction was incomplete, and some lead and tin remained in the slag, resulting in a slight decrease in recovery rate (approximately 1-1.5%). However, the purity was almost unaffected, demonstrating that the vacuum liquefaction temperature is crucial for improving the recovery rate of lead and tin. In Example 3, compared to Example 1, the carbonizable organic precursor was replaced with PEG-400. Because PEG-400 had a more uniform coating effect, the purity of silver and the recovery rate of tin were improved compared to Example 1. This demonstrates that the encapsulation properties of the carbonizable organic precursor material on the raw materials are crucial for achieving efficient tin-silver dissociation and improving metal recovery rate and purity. Compared to Example 1, in Example 4, the vacuum distillation temperature for lead was increased from 750℃ to 800℃ and the distillation time was extended from 2 hours to 2.5 hours, while the vacuum distillation temperature for tin was decreased from 1200℃ to 1150℃ and the distillation time was reduced from 2 hours to 1.5 hours. This resulted in a 0.4% decrease in Pb purity and a 0.5% decrease in tin recovery rate. This demonstrates that distillation temperature and holding time have an objective effect on improving metal extraction efficiency within a certain range. In Example 5, compared to Example 1, the vacuum distillation temperature for silver was decreased from 1400℃ to 1300℃ and the distillation time was reduced from 4 hours to 3 hours. This resulted in a 0.9% decrease in silver purity and a 1% decrease in silver recovery rate. This demonstrates that distillation temperature and distillation time are crucial for achieving efficient Ag extraction.

[0060] It should be noted that, compared with Comparative Example 1, Example 1 showed an increase in tin recovery rate of approximately 5.4% and silver recovery rate of approximately 2.0%, with an increase in product purity. The significant increase in recovery rate is attributed to the carbonizable organic precursor, which, after pyrolysis under vacuum heating, forms in-situ nano-confined structures on the surface and in the gaps of the tin-silver alloy. The resulting nano-carbon layer adds abundant defects and active sites to the entire system. The carbon layer has a stronger affinity for tin and easily migrates from the alloy system to the carbon layer interface, effectively reducing the energy barrier for tin-silver alloy reconstruction and relaxation. The formed carbon layer catalyzes the volatilization of tin due to the nano-confinement effect. Simultaneously, the carbon layer's coating effect on silver inhibits the synergistic volatilization of tin and silver, which is beneficial for controlling the volatilization behavior of tin and silver during vacuum vaporization—promoting preferential volatilization of tin atoms and inhibiting the volatilization of silver atoms. Ultimately, the tin and silver are volatilized and discharged at high temperatures, thus achieving catalytic tin-silver dissociation. Adding carbonizable organic precursors is crucial for achieving efficient tin-silver dissociation and improving metal recovery and purity.

[0061] Finally, it should be noted that the above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Although the present invention has been described in detail with reference to the foregoing embodiments, those skilled in the art can still modify the technical solutions described in the foregoing embodiments or make equivalent substitutions for some of the technical features. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the protection scope of the present invention.

Claims

1. A method for separating and extracting metal elements from decommissioned photovoltaic cells, characterized in that, include, The solder powder from retired photovoltaic cells is liquefied under vacuum to obtain silver-rich and lead-tin-rich materials. The silver-rich material is mixed with a carbonizable organic precursor to obtain a mixture. The mixture is then heated with a lead- and tin-rich material and subjected to a first vacuum vaporization treatment to obtain lead, primary tin, and secondary silver-rich materials. The secondary silver-rich material is subjected to a second vacuum gasification treatment to obtain secondary tin and tertiary silver-rich material. Silver is obtained by subjecting the three silver-rich materials to a third vacuum gasification treatment.

2. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The carbonizable organic precursor includes at least one of citric acid, glucose, sucrose, polyethylene glycol, and polyvinylpyrrolidone, accounting for 0.5%-2% of the silver-rich material.

3. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The particle size of the carbonizable organic precursor is 0.1-0.3 mm.

4. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The vacuum liquefaction process involves holding the material at a vacuum of 50-100 Pa and a temperature of 450-500 °C for 1-2 hours.

5. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The temperature is increased to 350-450℃ at a rate of 3-8℃ / min and held for 0.5-2 hours. The first vacuum gasification treatment is carried out at a vacuum degree of 1-10 Pa and a temperature of 700-800℃ for 1-2 hours.

6. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The second vacuum gasification treatment is carried out at a vacuum degree of 1-10 Pa and a temperature of 1100-1200℃ for 1-2 hours.

7. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The third vacuum gasification treatment is carried out at a vacuum of 1-10 Pa and a temperature of 1300-1400℃ for 3-4 hours.

8. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to claim 1, characterized in that, The collection of lead, tin, and silver is achieved by condensation at temperatures of 100-250°C.

9. The method for separating and extracting metal elements from decommissioned photovoltaic cells according to any one of claims 1-7, characterized in that, The solder powder of the retired photovoltaic cells is obtained by crushing, grinding, sieving, and physically sorting the solder of the retired photovoltaic cells to remove copper, silicon and residual encapsulation material fragments. The solder powder of the retired photovoltaic cells has a particle size of 0.1-0.5mm, and contains a total mass percentage of lead, tin and silver of not less than 85%, and a total mass percentage of aluminum and copper of less than 5%.

10. The application of the method for separating and extracting metal elements from decommissioned photovoltaic cells as described in any one of claims 1-9 in the treatment of decommissioned photovoltaic devices.

Images