Method for recycling solar waste panel

Abstract

A method for recycling a solar waste panel, which includes a glass substrate, a solar cell, an adhesive layer provided between the glass substrate and the solar cell and bonding the glass substrate and the solar cell, and a metal frame fixing the stacking structure of the glass substrate, the adhesive layer, and the solar cell, according to the present invention comprises: a first crushing process for crushing the solar waste panel into pieces no larger than a certain size; a frame removal process for sorting and removing the frame contained in first crushed pieces crushed by the first crushing process; a second crushing process for crushing the first crushed pieces, removed of the frame by the frame removal process, into pieces no larger than a certain size; a sintering process for removing the adhesive layer between the glass substrate and the solar cell by feeding second crushed pieces, crushed by the second crushing process, into a sintering furnace and heating same; a classification process for dividing the second crushed pieces that have undergone the sintering process into the glass substrate and the solar cell, and removing the glass substrate; and a dry furnace feeding process for feeding final crushed pieces, removed of the glass substrate, into a dry furnace for a dry smelting process.

Description

How to Recycle Waste Solar Panels

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

[0002] Solar power generation, utilizing clean energy like sunlight, is attracting attention as a renewable energy source due to its low environmental impact. Solar panels used for this type of 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 secures the glass substrate, adhesive layer, and solar cells into a single module.

[0003] Regarding the use of solar power generation, the proportion of renewable energy generation has increased rapidly since the early 2000s, and the proportion of solar power generation in particular has increased the most.

[0004] As solar power generation systems expand, the number of discarded solar panels is expected to increase exponentially. Given that solar panels have a service life of approximately 25 years, the number of discarded solar panels is expected to increase significantly starting in the mid- to late-2020s, as panels installed since the early 2000s reach the end of their lifespan. Consequently, various methods for disposing of discarded solar panels are being explored. However, current methods have limited themselves to landfilling the entire solar panel fleet without recycling, or recycling only the aluminum frames. The full recycling of discarded solar modules has yet to be achieved. Specifically, existing methods for disposing of discarded solar panels involve manually separating the aluminum frames and glass, selling them, and landfilling the remaining cells. While some companies are attempting to semi-automate and automate the process of separating the aluminum frames and glass using machines, these efforts are limited to small-scale operations and small-scale operations.

[0005] In particular, recycling solar cells, which are rich in silicon and contain significant amounts of copper and silver, is challenging. Recycling them using conventional shredding and sorting methods requires a complex process to separate valuable metals. The development of a recycling method capable of handling this problem is necessary, as is the development of an automated process capable of processing solar panels in large quantities.

[0006] The present invention provides a method for replacing a solvent made of silicon dioxide (SiO2) used in a dry refining process with waste solar panels by putting the waste solar panels into a dry furnace that performs a dry refining process for recovering valuable metals.

[0007] The present invention also provides a method for recovering a concentrated valuable metal from waste solar panels.

[0008] According to one embodiment of the present invention, a method for recycling a waste solar panel, which includes 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 frame made of a metal material to fix a laminated structure of the glass substrate, the adhesive layer, and the solar cell, comprises: a first crushing process for crushing the waste solar panel into pieces smaller than a predetermined size; a frame removal process for selecting and removing the frame included in the first piece crushed by the first crushing process; a second crushing process for crushing the first piece from which the frame has been removed by the frame removal process into pieces smaller than a predetermined size; a firing process for removing the adhesive layer between the glass substrate and the solar cell by feeding the second piece crushed by the second crushing process into a firing furnace and heating it; a classification process for separating the second piece that has undergone the firing process into the glass substrate and the solar cell and removing the glass substrate; and a dry furnace feeding process for feeding the final piece from which the glass substrate has been removed into a dry furnace of a dry refining process.

[0009] The first crushing process can crush the solar waste panel into pieces of 150 mm or less in size, and the second crushing process can crush the first pieces into pieces of 50 mm or less in size.

[0010] The first crushing process and the second crushing process are performed through 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 by passing through a screen provided at the bottom of the crusher.

[0011] The frame of the above metal material is made of aluminum, and the frame removal process can be performed by a eddy current sorter.

[0012] The above firing process can be performed at a temperature of 500°C to 600°C for 2 to 3 hours.

[0013] The above adhesive layer is composed of ethylene vinyl acetate (EVA), and the ethylene vinyl acetate can be removed by combustion or sublimation through the firing process.

[0014] The above classification process can be performed through sieving classification using the difference in particle size between the crushed glass substrate and the crushed solar cell.

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

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

[0017] In the above dry furnace feeding process, the amount of final crushed material fed into the dry furnace can be calculated by considering the composition ratio of silicon dioxide in the solvent fed into the dry smelting process.

[0018] According to the present invention, recycled foundry sand (containing SiO2) used as one of the solvents in a dry smelting process can be replaced with waste solar panels.

[0019] Additionally, valuable metals such as silver and copper contained in solar waste panels can be concentrated and recovered.

[0020] Figure 1 is a process flow diagram of a method for recycling solar waste panels according to one embodiment of the present invention.

[0021] In describing the present invention, if it is judged that the detailed description of related known functions that are obvious to those skilled in the art and may unnecessarily obscure the gist of the present invention, will be omitted.

[0022] The present invention relates to a method for recycling waste solar panels using a conventional dry smelting process. The recycling method according to the present invention mainly uses waste solar panels for recycling, but is not necessarily limited thereto, and all industrial wastes 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 replacing silicon dioxide used in a dry refining process by processing waste solar panels and introducing the processed solar panels into a dry furnace that performs a conventional dry refining process, and for recovering valuable metals contained in waste solar panels.

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

[0025] The solar waste panel that is the subject of recycling of the present invention includes 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 provided on the edge of the solar panel to fix the laminated structure of the glass substrate, the adhesive layer, and the solar cell.

[0026] Referring to Fig. 1, solar waste panels are fed into a shredder, and the solar waste panels are shredded into sizes of 150 mm or less by the shredder (first shredding process (S1)). The first shredding process (S1) is performed by the shredder, and the waste panels shredded into sizes of 150 mm or less by the first shredding process (S1) pass through a screen provided at the bottom of the shredder and are discharged as first shredded material. As a means for performing the first shredding process (S1), any means capable of shredding glass substrates, solar cells, metal frames, etc. included in solar waste panels can be used, and for example, a known shredder such as a single-axis shredder or a dual-axis shredder can be used.

[0027] The first shredded material shredded by the first shredding process (S1) is transferred to the frame removal process (S2), and in the frame removal process (S2), the metal frame material contained in the first shredded material is selected and removed from the first shredded material. The first shredded material obtained by shredding solar waste panels contains metal frame materials that fixed the laminated structure of the solar waste panels, and the metal frame may be made of aluminum. The first shredded material containing the shredded aluminum frames is transferred to an eddy current sorter, and the eddy current sorter can select and remove the shredded aluminum frames from the first shredded material. The eddy current sorter selects non-ferrous metals such as aluminum that are small and light through eccentric eddy current technology, and is equipped with a magnet that can be angle-adjusted and has a strong magnetic field, so that the aluminum component contained in the first shredded material can be selected and separated.

[0028] The first shredded material from which the aluminum frame has been removed by the frame removal process (S2) is transferred to the second shredding process (S3). In the second shredding process (S3), the first shredded material is shredded into a size of 50 mm or less. The second shredding process (S3) is performed using a shredder, and the first shredded material shredded into a size of 50 mm or less by the second shredding process (S3) passes through a screen provided at the bottom of the shredder and is discharged as the second shredded material. The second shredding process (S3) can be performed in the same manner as the first shredding process (S1), and the first shredded material can be shredded into a size (50 mm or less) smaller than the target shredding size (150 mm or less) in the first shredding process (S1) by appropriately adjusting the number of blades of the shredder, the clearance of the blades, the rotation speed of the blades, etc.

[0029] The second crushed material crushed by the second crushing process (S3) is fed into the firing process (S4). In the firing process (S4), the second crushed material is fed into a firing furnace and heated to remove the adhesive layer between the glass substrate and the solar cell from the second crushed material. The adhesive layer may be composed of ethylene vinyl acetate (EVA). The firing process (S4) may be performed in the furnace at a temperature of 500°C to 600°C for 2 to 3 hours, and through the firing process (S4), the adhesive layer composed of EVA between the glass substrate and the solar cell from the second crushed material may be removed through combustion or sublimation. When the firing process (S4) is completed, the adhesive layer is removed, leaving only the crushed glass substrate and solar cell. In particular, the high-temperature heating process in the firing process leaves the solar cell in the form of a powder, whereas the crushed glass substrate has a particle size similar to that before being fed into the firing furnace.

[0030] The second crushed material that has gone through the firing process (S4) contains crushed glass substrates and solar cells, and the glass substrates and solar cells included 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 difference in particle sizes between the glass substrates included in the second crushed material that has gone through the firing process (S4) and the solar cells. Since the second crushed material contains solar cells in powder form and glass substrates having particle sizes larger than the solar cells after going through the firing process (S4), the glass substrates having particle sizes larger than the solar cells can be separated and removed from the solar cells in powder form through the classification process (S5). The solar cells in powder form from which the glass substrates have been removed can contain silicon (Si), silver (Ag), copper (Cu), etc. as the final crushed material.

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

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

[0033] Specifically, in the dry refining process, a solvent is injected to increase the fluidity of the melt, and the injection of a solvent is especially necessary when metal waste is the raw material. This is because natural ores themselves contain a large amount of solvent components such as SiO2 and Al2O3, but the content of such solvent components is insufficient in metal waste. Therefore, the injection of a solvent is essential in the dry refining process of metal waste, and in the past, mainly recycled foundry sand or sand was used as a silicon dioxide (SiO2) solvent. In the present invention, the final crushed material containing silicon (Si), silver (Ag), copper (Cu), etc. obtained from waste solar panels is injected into the dry furnace of the dry refining process, and silicon (Si), which is the main component of the final crushed material, reacts with oxygen in the dry furnace to form silicon dioxide (SiO2), thereby functioning as a solvent. In other words, by feeding waste solar panels into a dry furnace that performs a dry refining process for the recovery of valuable metals, the solvent composed of silicon dioxide (SiO2) fed into the dry refining process can be replaced by recycling the waste solar panels. In the dry furnace feeding process (S6), the amount of final shredded material fed into the dry furnace can be calculated by considering the composition ratio of silicon dioxide in the solvent fed into the dry refining process.

[0034] While the present invention has been described in connection with certain embodiments herein, it should be understood that various modifications and variations can be made without departing from the spirit and scope of the invention, as understood by those skilled in the art. Furthermore, such modifications and variations are intended to fall within the scope of the claims appended to this specification.

Claims

1. A method for recycling a solar waste panel, 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 that fixes the laminated structure of the glass substrate, the adhesive layer, and the solar cell. A first crushing process for crushing the above solar waste panels into a size smaller than a predetermined size; A frame removal process for selecting and removing the frame contained in the first shredded material shredded by the first shredding process; A second crushing process for crushing the first crushed material from which the frame has been removed by the frame removing process into a size smaller than a predetermined size; A firing process for removing the adhesive layer between the glass substrate and the solar cell by heating the second crushed material crushed by the second crushing process in a firing furnace; A classification process in which the second crushed material that has undergone the above-mentioned firing process is separated into the glass substrate and the solar cell, and the glass substrate is removed; and A method for recycling waste solar panels, comprising a dry furnace feeding process of feeding the final shredded material from which the glass substrate has been removed into a dry furnace of a dry refining process.

2. In paragraph 1, A method for recycling waste solar panels, wherein the first crushing process crushes the waste solar panels into a size of 150 mm or less, and the second crushing process crushes the first crushed material into a size of 50 mm or less.

3. In paragraph 2, The above first crushing process and the above second crushing process are performed through a crusher, A method for recycling solar waste panels, wherein the first shredded material crushed to a size of 150 mm or less in the first shredding process and the second shredded material crushed to a size of 50 mm or less in the second shredding process are discharged by passing through a screen provided at the bottom of the shredder.

4. In paragraph 1, The above metal material frame is made of aluminum, A method for recycling solar waste panels, wherein the above frame removal process is performed by a eddy current sorter.

5. In paragraph 1, A method for recycling waste solar panels, wherein the above-mentioned calcination process is performed at a temperature of 500°C to 600°C for 2 to 3 hours.

6. In paragraph 5, The above adhesive layer is composed of ethylene vinyl acetate (EVA), A method for recycling waste solar panels, wherein the ethylene vinyl acetate is removed by combustion or sublimation through the above-mentioned calcination process.

7. In paragraph 1, The above classification process is a method for recycling waste solar panels, which is performed through sieving classification using the difference in particle size between the crushed glass substrate and the crushed solar cells.

8. In paragraph 7, A method for recycling waste solar panels, wherein the final shredded material from which the glass substrate has been removed contains silicon (Si), silver (Ag) and copper (Cu).

9. In paragraph 8, A method for recycling waste solar panels, wherein silver and copper are concentrated in the final shredded material through the above classification process.

10. In paragraph 1, A method for recycling waste solar panels, wherein the amount of final crushed material fed into the dry furnace in the above dry furnace feeding process is calculated by considering the composition ratio of silicon dioxide in the solvent fed into the dry smelting process.

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