How to recycle used solar panels

Abstract

According to one embodiment of the present invention, a method for recycling waste solar panels including glass substrates, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells, and a metal frame to fix a laminated structure of the glass substrate, the adhesive layer, and the solar cells includes: a first crushing process of crushing the waste solar panels to a predetermined size or smaller; a frame removing process of selecting and removing the frames included in the first crushed materials crushed in the first crushing process; a second crushing process of crushing the first crushed materials from which the frames have been removed to a predetermined size or smaller; a firing process of introducing the second crushed materials crushed in the second crushing process into a firing furnace and heating it to remove the adhesive layer between the glass substrate and the solar cells; a classification process of separating the second crushed materials that have been subjected to the firing process into the glass substrates and the solar cells and removing the glass substrates; and a dry furnace introducing process of introducing the final crushed materials from which the glass substrates have been removed into a dry furnace for a pyrometallurgical process.

Description

[Technical Field]

[0001] The present invention relates to a method for recycling waste solar panels. [Background technology]

[0002] Solar power generation is attracting attention as a renewable energy source because it uses the clean energy of sunlight and has a small environmental impact. Solar panels used in solar power generation are composed of a glass substrate, solar cells, an adhesive layer such as ethylene vinyl acetate (EVA) between the solar cells and the glass substrate to bond them together, and an aluminum frame that fixes the glass substrate, adhesive layer, and solar cells into a module.

[0003] In terms of solar power generation, the proportion of renewable energy generation has increased rapidly since the early 2000s, with solar power generation seeing the greatest increase.

[0004] As the use of solar power generation systems expands, the amount of discarded solar panels is expected to increase exponentially. Considering the average lifespan of a solar panel is approximately 25 years, the generation of discarded solar panels is expected to increase significantly from the mid-to-late 2020s as solar panels installed since the early 2000s reach the end of their lifespan. As a result, various methods for disposing of discarded solar panels are being explored. However, until now, discarded solar panels have been landfilled without recycling, or only the aluminum frames are separated and recycled. This has prevented progress toward full recycling of discarded solar modules. Specifically, the current method for disposing of discarded solar panels involves manually separating the aluminum frame and glass, selling them, and landfilling the remaining cells. While some companies are attempting to semi-automate or automate the process of separating the aluminum frame and glass using machines, most of these operations are small and require small-scale processing.

[0005] In particular, solar cells, which are rich in silicon and contain significant amounts of copper and silver, are rarely recycled, and recycling them through conventional crushing and sorting methods to separate the valuable metals requires complex processes. Development of a recycling method that can handle this is necessary, as well as the development of an automated process that can process large quantities of solar panels. Summary of the Invention [Problem to be solved by the invention]

[0006] The present invention provides a method for replacing the solvent made of silicon dioxide (SiO2) input into a dry furnace for dry refining to recover valuable metals with waste solar panels.

[0007] The present invention also provides a method for recovering a recovered material in which valuable metals are concentrated from waste solar panels. [Means for solving the problem]

[0008] According to one embodiment of the present invention, a method for recycling waste solar panels including glass substrates, solar cells, an adhesive layer disposed between the glass substrate and the solar cells to bond the glass substrate and the solar cells, and a metal frame to fix a laminated structure of the glass substrate, the adhesive layer, and the solar cells includes: a first crushing process of crushing the waste solar panels to a predetermined size or smaller; a frame removing process of selecting and removing the frames included in the first crushed materials crushed in the first crushing process; a second crushing process of crushing the first crushed materials from which the frames have been removed to a predetermined size or smaller; a firing process of introducing the second crushed materials crushed in the second crushing process into a firing furnace and heating it to remove the adhesive layer between the glass substrate and the solar cells; a classification process of separating the second crushed materials that have been subjected to the firing process into the glass substrates and the solar cells and removing the glass substrates; and a dry furnace introducing process of introducing the final crushed materials from which the glass substrates have been removed into a dry furnace for a pyrometallurgical process.

[0009] The first crushing step may crush the waste solar panels into pieces of 150 mm or less in size, and the second crushing step may crush the first crushed pieces into pieces of 50 mm or less in size.

[0010] The first crushing process and the second crushing process are performed using a crusher, and the first crushed material crushed to a size of 150 mm or less in the first crushing process and the second crushed material crushed to a size of 50 mm or less in the second crushing process can be discharged through a screen installed at the bottom of the crusher.

[0011] The metal frame is made of aluminum, and the frame removal process can be performed by an eddy current separator.

[0012] The firing step may be carried out at a temperature of 500° C. to 600° C. for 2 to 3 hours.

[0013] The adhesive layer is made of ethylene vinyl acetate (EVA), and the ethylene vinyl acetate can be burned or sublimated and removed by the baking process.

[0014] The classification process may be performed by sieving the crushed glass substrates and the crushed solar cells based on the particle size difference.

[0015] The final crushed material from which the glass substrate has been removed may contain silicon (Si), silver (Ag), and copper (Cu).

[0016] Through the classification process, silver and copper can be enriched in the final crushed material.

[0017] The amount of the final crushed material to be charged into the dry furnace in the dry furnace charging step can be calculated taking into account the composition ratio of silicon dioxide in the solvent to be charged into the dry smelting step. [Effects of the Invention]

[0018] According to the present invention, recycled foundry sand (containing SiO2) that is added as one of the solvents in the pyrometallurgical process can be replaced with waste solar panels.

[0019] In addition, valuable metals such as silver and copper contained in waste solar panels can be concentrated and recovered. [Brief explanation of the drawings]

[0020] [Figure 1] FIG. 1 is a process flowchart of a method for recycling waste solar panels according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0021] In describing the present invention, detailed descriptions of related known functions will be omitted if they are obvious to those skilled in the art and are deemed to unnecessarily obscure the gist of the present invention.

[0022] The present invention relates to a method for recycling waste solar panels using an existing pyrometallurgical process. The recycling method according to the present invention mainly uses waste solar panels, but is not necessarily limited thereto, and any industrial waste containing silicon and valuable metals can be subject to the recycling method according to the present invention.

[0023] The present invention provides a method for recovering valuable metals contained in waste solar panels by processing the waste solar panels and feeding them into a dry furnace that performs an existing dry smelting process, thereby replacing the silicon dioxide that is fed into the dry smelting process.

[0024] FIG. 1 is a process flowchart of a method for recycling waste solar panels according to one embodiment of the present invention.

[0025] The waste solar panel that is the target of recycling in the present invention includes a glass substrate, a solar cell, an adhesive layer that is provided between the glass substrate and the solar cell and bonds the glass substrate and the solar cell, and a metal frame that is provided on the frame of the solar panel by fixing the laminated structure of the glass substrate, adhesive layer, and solar cell.

[0026] Referring to FIG. 1, waste solar panels are fed into a crusher, which crushes them into pieces of 150 mm or less (first crushing step (S1)). The first crushing step (S1) is performed using a crusher, and the waste panels crushed into pieces of 150 mm or less by the first crushing step (S1) pass through a screen installed at the bottom of the crusher and are discharged as first crushed material. Any means can be used to perform the first crushing step (S1) as long as it can crush the glass substrates, solar cells, metal frames, etc. contained in the waste solar panels. For example, a known crusher such as a uniaxial crusher or a biaxial crusher can be used.

[0027] The first crushed material from the first crushing process (S1) is transferred to the frame removal process (S2), where the metal frame material contained in the first crushed material is separated and removed. The first crushed material, which is made from crushed solar waste panels, includes the metal frame material that fixed the laminated structure of the solar waste panels. The metal frame material may be made of aluminum. The first crushed material, including the crushed aluminum frame material, is transferred to a vortex separator, which separates and removes the crushed aluminum frame material from the first crushed material. The vortex separator uses eccentric vortex technology to separate small, lightweight non-ferrous metals such as aluminum. It is equipped with an adjustable angle magnet with a strong magnetic field, which allows it to separate and remove the aluminum component contained in the first crushed material.

[0028] The first crushed materials, from which the aluminum frames have been removed in the frame removal process (S2), are transferred to the second crushing process (S3). In the second crushing process (S3), the first crushed materials are crushed to sizes of 50 mm or less. The second crushing process (S3) is carried out using a crusher, and the first crushed materials crushed to sizes of 50 mm or less in the second crushing process (S3) pass through a screen installed at the bottom of the crusher and are discharged as second crushed materials. The second crushing process (S3) can be carried out in the same manner as the first crushing process (S1), and the number of crusher blades, blade clearance, blade rotation speed, etc. can be appropriately adjusted to crush the first crushed materials to a size (50 mm or less) smaller than the target crush size (150 mm or less) in the first crushing process (S1).

[0029] The second crushed material obtained in the second crushing step (S3) is then sent to the firing step (S4). In the firing step (S4), the second crushed material is placed in a firing furnace and heated to remove the adhesive layer between the glass substrate and the solar cells from the second crushed material. The adhesive layer may be made of ethylene vinyl acetate (EVA). The firing step (S4) may be performed in a firing furnace at a temperature of 500°C to 600°C for 2 to 3 hours. During the firing step (S4), the adhesive layer made of EVA between the glass substrate and the solar cells from the second crushed material is burned or sublimated and removed. Upon completion of the firing step (S4), the adhesive layer is removed, leaving only the crushed glass substrate and solar cells. In particular, the solar cells remain in powder form due to the high-temperature heating process in the firing step, while the crushed glass substrates have a particle size similar to that before being placed in the firing furnace.

[0030] The second crushed material after the firing process (S4) includes crushed glass substrates and solar cells, and the glass substrates and solar cells contained in the second crushed material can be separated through a classification process (S5). The classification process (S5) can be performed through sieving classification using the particle size difference between the glass substrates and solar cells contained in the second crushed material after the firing process (S4). Since the second crushed material includes powdered solar cells and glass substrates with a particle size larger than the solar cells after the firing process (S4), the glass substrates with a larger particle size can be separated and removed from the powdered solar cells through the classification process (S5). The powdered solar cells from which the glass substrates have been removed can contain silicon (Si), silver (Ag), copper (Cu), etc. as the final crushed material.

[0031] As described above, valuable metals contained in the solar cell, such as silver and copper, can be concentrated by removing the glass substrate, resin, and other impurities through the classification step (S5).

[0032] The final crushed material, from which the glass substrates have been removed through the classification process (S5), is fed into the dry furnace of the pyrometallurgical process (dry furnace feeding process (S6)). By recycling the final crushed material, which contains silicon (Si), silver (Ag), copper (Cu), etc., as a solvent and fuel for the pyrometallurgical process, not only can valuable metals such as silver and copper be recovered from the used solar panels, but the amount of solvent and fuel input into the pyrometallurgical process can also be dramatically reduced.

[0033] Specifically, in the pyrometallurgical process, a solvent is added to increase the fluidity of the melt, and this is especially necessary when metal waste is used as the raw material. Natural ores themselves contain large amounts of solvent components such as SiO2 and Al2O3, but metal waste lacks these components. Therefore, adding a solvent is essential in the pyrometallurgical process for metal waste. Conventionally, recycled foundry sand or sand has been used as a silicon dioxide (SiO2) solvent. In this invention, the final crushed material, containing silicon (Si), silver (Ag), copper (Cu), etc., obtained from solar waste panels is added to a dry furnace in the pyrometallurgical process. Silicon (Si), the main component of the final crushed material, reacts with oxygen in the dry furnace to form silicon dioxide (SiO2), which functions as a solvent. That is, by feeding the waste solar panels into a dry furnace that performs a dry refining process to recover valuable metals, the solvent made of silicon dioxide (SiO2) that is fed into the dry refining process can be replaced by recycling the waste solar panels. The amount of final crushed material fed into the dry furnace in the dry furnace feeding step (S6) can be calculated taking into account the composition ratio of silicon dioxide in the solvent fed into the dry refining process.

[0034] Although the present invention has been described herein with reference to certain embodiments, it should be understood that various modifications and changes may be made thereto without departing from the spirit and scope of the present invention, as would be understood by one of ordinary skill in the art to which the present invention pertains, and such modifications and changes should be considered to fall within the scope of the claims appended hereto.

Claims

1. A method for recycling used solar panels comprising a glass substrate, a solar cell, an adhesive layer provided between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame to fix a laminated structure of the glass substrate, the adhesive layer, and the solar cell, a first crushing step of crushing the waste solar panels to a predetermined size or smaller; a frame removing step of selecting and removing the frames contained in the first crushed material crushed in the first crushing step; a second crushing step of crushing the first crushed object from which the frame has been removed in the frame removing step to a size equal to or smaller than a predetermined size; a firing step of introducing the second crushed pieces obtained in the second crushing step into a firing furnace and heating the pieces to remove the adhesive layer between the glass substrate and the solar cell; a classification step of separating the second crushed material that has undergone the firing step into the glass substrate and the solar cell, and removing the glass substrate; and A method for recycling waste solar panels, comprising a dry furnace charging step of charging the final crushed material from which the glass substrate has been removed into a dry furnace of a dry smelting step.

2. 2. The method for recycling waste solar panels according to claim 1, wherein the first crushing step crushes the waste solar panels into pieces having a size of 150 mm or less, and the second crushing step crushes the first crushed pieces into pieces having a size of 50 mm or less.

3. The first crushing step and the second crushing step are carried out using a crusher, 3. The method for recycling waste solar panels according to claim 2, wherein the first crushed material crushed to a size of 150 mm or less in the first crushing step and the second crushed material crushed to a size of 50 mm or less in the second crushing step are discharged after passing through a screen provided at a bottom of the crusher.

4. The metal frame is made of aluminum, 2. The method for recycling waste solar panels according to claim 1, wherein the frame removal step is performed by an eddy current separator.

5. 2. The method for recycling waste solar panels according to claim 1, wherein the firing step is carried out at a temperature of 500°C to 600°C for 2 hours to 3 hours.

6. The adhesive layer is made of ethylene vinyl acetate (EVA), 6. The method for recycling waste solar panels according to claim 5, wherein the ethylene vinyl acetate is removed by combustion or sublimation in the firing step.

7. The method for recycling waste solar panels according to claim 1 , wherein the classification step is performed by sieving and classifying the crushed glass substrates and the crushed solar cells based on particle size differences.

8. 8. The method for recycling waste solar panels according to claim 7, wherein the final crushed material from which the glass substrate has been removed contains silicon (Si), silver (Ag), and copper (Cu).

9. The method for recycling waste solar panels according to claim 8 , wherein silver and copper are concentrated in the final crushed material through the classification process.

10. 2. The method for recycling waste solar panels according to claim 1, wherein the amount of final crushed material to be fed into the dry furnace in the dry furnace feeding step is calculated taking into account the composition ratio of silicon dioxide in the solvent to be fed into the dry smelting step.

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