Waste solar panel recycling method

Abstract

According to one embodiment of the present invention, a method for recycling a waste solar panel includes a glass substrate, 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 configured to stabilize the multilayer structure of the glass substrate, the adhesive layer, and the solar cells, the method comprising the following: A primary crushing process for crushing waste solar panels to a predetermined size or less; a frame removal process comprising sorting and removing the frame present in the primary crushed material crushed by the primary crushing process; a secondary crushing process for crushing the primary crushed material from which the frame has been removed by the frame removal process to a predetermined size or less; a roasting process for removing the adhesive layer between the glass substrate and the solar cells by introducing the second crushed material crushed by the secondary crushing process into a a roasting and heating furnace for the second crushed material; a classification process for separating the second crushed material that has undergone the roasting process into glass substrate and solar cells and removing the glass substrate; and a dry kiln feeding process that includes feeding the final crushed material from which the glass substrate has been separated into a dry kiln in a melting process.

Description

How to recycle waste solar panels Technical background

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

[0002] Solar power generation has attracted attention as a renewable energy source because it has a low environmental burden by utilizing clean energy from sunlight. A solar panel used for this solar power generation includes a glass substrate, solar cells, an adhesive layer such as ethylene vinyl acetate (EVA) that is interposed between the solar cells and the glass substrate and bonds the solar cells and the glass substrate, an aluminum frame that secures the glass substrate, adhesive layer, solar cells, and the like into a module, and the like.

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

[0004] As solar power generation systems expand, the number of used solar panels that have reached the end of their life is expected to increase exponentially. Given that the lifespan of a solar panel is approximately 25 years, as solar panels installed since the early 2000s approach the end of their life, a large number of scrap solar panels are expected to appear from the mid- to late 2020s. Accordingly, various methods for processing scrap solar panels are being investigated. However, so far, all scrap solar panels have been buried without recycling, or only the aluminum frames have been separated and recycled, and complete recycling of scrap solar modules has not yet been achieved. Specifically, the current existing scrap solar panel processing method is to manually separate the aluminum frames and glass for sale and bury the remaining parts of the solar cells. Some companies have attempted to semi-automate and automate the process of separating aluminum frames and glass using machinery, but most companies are small and have little processing capacity.

[0005] In particular, solar cells, which are rich in silicon and contain significant amounts of copper and silver, are not easily recycled and require complex processes to separate the valuable metals from their recycling through general crushing and sorting methods. Accordingly, there is a need to develop a recycling method that can handle this and also a need to develop an automated process that can process solar panels in large quantities. Summary

[0006] The present disclosure provides a method for replacing the flux made of silicon dioxide (SiO2) used in the smelting process with a scrap solar panel, which is accomplished by introducing the scrap solar panel into a smelting furnace that performs the smelting process to recover valuable metals.

[0007] Furthermore, the present disclosure provides a method for recovering a valuable metal-focused material from a waste solar panel.

[0008] According to an embodiment of the present invention, a method for recycling a waste solar panel includes a glass substrate, solar cells, an adhesive layer between the glass substrate and the solar cells for bonding the glass substrate and the solar cells, and a metal frame configured to stabilize a multilayer structure of the glass substrate, the adhesive layer, and the solar cells, the method comprising: a primary crushing process for crushing the waste solar panel to a predetermined size or less; a frame removal process for sorting and removing the frame present in a primary crushed material crushed by the first crushing process; a second crushing process comprising crushing the first crushed material from which the frame has been separated by the frame removal process to a predetermined size or less; a roasting process comprising removing the adhesive layer between the glass substrate and the solar cells by feeding the second crushed material crushed by the second crushing process into a roasting furnace and heating the second crushed material; A classification process involves separating the second crushed material that has undergone the roasting process onto a glass substrate.and solar cells and glass substrate removal; and a dry kiln feed process comprising feeding the final crushed material from which the glass substrate has been removed into a dry kiln from a melting process.

[0009] In the first crushing process, the waste solar panel is crushed to a size of 150 mm or less, and in the second crushing process, the first crushed material is crushed to a size of 50 mm or less.

[0010] The first crushing process and the second crushing process are carried out through a crusher, and the first crushed materials crushed to a size of 150 mm or less in the first crushing process and the second crushed materials crushed to a size of 50 mm or less in the second crushing process are discharged through a screen installed at the bottom of the crusher.

[0011] The metal frame is made of aluminum and the frame removal process is carried out by an eddy current separator.

[0012] The roasting process is carried out at a temperature of 500 to 600 degrees Celsius for 2 to 3 hours.

[0013] The adhesive layer is made of ethylene vinyl acetate (EVA), and the ethylene vinyl acetate is removed by combustion or sublimation through a roasting process.

[0014] The classification process is carried out by sieving using the difference in particle size between the crushed glass substrate and the crushed solar cells.

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

[0016] Silver and copper are concentrated from the final crushed material through a classification process.

[0017] The final amount of crushed material entering the dry kiln in the dry kiln feed process is calculated based on the proportion of silicon dioxide composition in the feed stream entering the melting process.

[0018] According to the present disclosure, recycled foundry sand (including SiO2) introduced as one of the fluxes in the melting process can be replaced with a waste solar panel.

[0019] Furthermore, valuable metals such as silver and copper contained in a waste solar panel can be concentrated and recovered. Brief description of the maps

[0020] Figure 1 is a process flow diagram of a method for recycling a waste solar panel in accordance with an embodiment of the present disclosure. Detailed description

[0021] In describing the present disclosure, when it is determined that related well-known functions are obvious to those skilled in the art and that a detailed description of the functions would unnecessarily obscure the gist of the present disclosure, the detailed description will be omitted.

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

[0023] The present disclosure provides a method for processing scrap solar panels and introducing the processed scrap solar panels into a dry furnace that performs a conventional melting process, thereby replacing the silicon dioxide input to the melting process and recovering the valuable metals contained in the scrap solar panels.

[0024] Figure 1 is a process flow diagram of a method for recycling waste solar panels in accordance with an embodiment of the present disclosure.

[0025] A waste solar panel subject to recycling of the present disclosure includes a glass substrate, 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 configured to secure a multilayer structure of the glass substrate, adhesive layer, and solar cells and disposed at a peripheral edge of a solar panel.

[0026] Referring to FIG. 1, a waste solar panel is fed into a crusher, and the waste solar panel is crushed by the crusher to a size of 150 mm or less (first crushing process S1). The first crushing process S1 is performed using a crusher, in which the waste panel is crushed by the first crushing process S1 to a size of 150 mm or less, and the crushed waste panel is discharged as the first crushed material through a plate provided at the bottom of the crusher. Any mechanism that can crush a glass substrate, solar cells, a metal frame, and the like contained in the waste solar panel can be used as the mechanism for performing the first crushing process S1. For example, a known crusher such as a single-shaft crusher or a double-shaft crusher can be used.

[0027] The first crushed material is conveyed by the first crushing process S1 to a frame removal process S2, and in the frame removal process S2, the metal frame material contained in the first crushed material is sorted and removed from the first crushed material. The first crushed material resulting from the crushing of the waste solar panel contains metal frame materials that support the multilayer structure of the waste solar panel, and the metal frame may be made of aluminum. The first crushed material containing the crushed aluminum frame is conveyed to an eddy current separator, and the eddy current separator is capable of sorting and removing the crushed aluminum frame from the first crushed material. The eddy current separator uses eccentric eddy current technology to sort small, crushed, and light non-ferrous metals such as aluminum, and is equipped with an angle-adjustable magnet having a strong magnetic field to sort and separate the aluminum components contained in the first crushed material.

[0028] The first crushed material from which the aluminum frame has been separated by the frame removal process S2 is transferred to the second crushing process S3. In the second crushing process S3, the first crushed material is crushed to a size of 50 mm or less. The second crushing process S3 is carried out using a crusher, in which the waste panel is crushed to a size of 50 mm or less by the second crushing process S3, and the first crushed material is discharged as the second crushed material through a screen provided at the bottom of the crusher. The second crushing process S3 can be carried out in the same manner as the first crushing process S1, in which the first crushed material can be crushed to a size (50 mm or less) smaller than the target crushed size (150 mm or less) in the first crushing process S1 by appropriately adjusting the number of crusher blades, blade spacing, blade rotation speed, and the like.

[0029] The second crushed material crushed by the second crushing process S3 enters the sintering process S4. In the roasting process S4, the second crushed material is entered into a roasting furnace and heated to separate 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 roasting process S4 may be carried out in a roasting furnace at a temperature of 500 to 600°C for 2 to 3 hours. Through the roasting process S4, the EVA adhesive layer between the glass substrate and the solar cells may be separated from the second crushed material by combustion or sublimation. When the roasting process S4 is completed, the adhesive layer is removed, leaving only the crushed glass substrate and the solar cell. Specifically, solar cells remain in powder form during the high-temperature roasting process, while the crushed glass substrate has a similar particle size before entering the roasting furnace.

[0030] The second crushed material that has undergone the roasting process S4 contains the crushed glass substrate and the solar cell, and the glass substrate and the solar cell in the second crushed material can be separated through the classification process S5. The classification process S5 can be carried out through sieving classification using the difference in particle size between the glass substrate and the solar cells in the second crushed material after the roasting process S4. After undergoing the roasting process S4, the second crushed material contains the solar cells in powder form and the glass substrate with a particle size larger than the solar cells. Therefore, the glass substrate with a larger particle size can be separated from the solar cells in powder form and removed through the classification process S5. The powdered solar cells from which the glass substrate has been removed are the final crushed material and may contain silicon (Si), silver (Ag), copper (Cu), and the like.

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

[0032] The final crushed material from which the glass substrate has been separated through the classification process S5 enters the dry furnace of the melting process (dry furnace inlet process S6). Not only can valuable metals such as silver and copper be recovered from a waste solar panel by recycling the final crushed material containing silicon (Si), silver (Ag) and copper (Cu) as flux and fuel for the melting process, but also the amount of flux and fuel input to the melting process can be significantly reduced.

[0033] In particular, in the melting process, a flux is introduced to increase the fluidity of the melt, and especially, when metal scrap is used as a raw material, the introduction of a flux is even more necessary. The reason for this is that natural ore itself contains a large amount of flux components such as SiO2 and Al2O3, but the content of such flux components in metal scrap is not sufficient. Accordingly, the introduction of a flux is necessary in the melting process of metal scrap, and previously, sand or recycled foundry sand was mainly used as a silicon dioxide (SiO2) flux. In the present disclosure, the final crushed material containing silicon (Si), silver (Ag), copper (Cu) and the like obtained from a waste solar panel is introduced into a dry furnace of a melting process, and silicon (Si), which is the main component of the final crushed material, reacts with oxygen in the dry furnace to produce silicon dioxide (SiO2) and thus acts as a flux.That is, a flux made of silicon dioxide (SiO2) entering a smelting process can be replaced by recycling a waste solar panel by feeding the waste solar panel into a smelting furnace that performs the smelting process to recover valuable metals. The amount of final crushed material entering the dry kiln in the S6 dry kiln inlet process can be calculated based on the proportion of silicon dioxide in the flux entering the smelting process.

[0034] Although the present disclosure has been described in connection with certain embodiments thereof, it should be understood that various modifications and changes can be made without departing from the spirit and scope of the present disclosure, which may be obvious to a person of ordinary skill in the art to which the present disclosure pertains. Moreover, such modifications and changes should be considered within the scope of the claims appended hereto.

Claims

What is claimed:

1. A method for recycling a waste solar panel comprising a glass substrate, 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 configured to stabilize the multilayer structure of the glass substrate, the adhesive layer, and the solar cells, the method comprising: a primary crushing process for crushing the waste solar panels to a predetermined size or less; a frame removal process comprising sorting and removing the frame present in the primary crushed material crushed by the primary crushing process; a secondary crushing process for crushing the primary crushed material from which the frame has been removed by the frame removal process to a predetermined size or less; a roasting process for removing the adhesive layer between the glass substrate and the solar cells by feeding the second crushed material crushed by the secondary crushing process into a roasting furnace and heating the second crushed material; Classification process to separate the second crushed material that has undergone the roasting process into the substrateglass and solar cells and removing the glass substrate; and a dry kiln feed process comprising feeding the final crushed material from which the glass substrate has been separated into a dry kiln of a melting process.

2. The method of claim 1, wherein, in the first crushing process, the solar panel waste is crushed to a size of 150 mm or less and in the second crushing process, the first crushed material is crushed to a size of 50 mm or less.

3. The method of claim 2, wherein the first crushing process and the second crushing process are carried out through a crusher, and the first crushed materials crushed to a size of 150 mm or less in the first crushing process and the second crushed materials crushed to a size of 50 mm or less in the second crushing process are discharged through a screen provided at the bottom of the crusher.

4. The method of claim 1, wherein the metal frame is made of aluminum and the frame removal process is performed by an eddy current separator.

5. The method of claim 1, wherein the roasting process is carried out at a temperature of 500 to 600 degrees Celsius for 2 to 3 hours.

6. The method of claim 5, wherein the adhesive layer is made of ethylene vinyl acetate (EVA), and the ethylene vinyl acetate is removed by combustion or sublimation through a roasting process.

7. The method of claim 1, wherein the classification process is performed by sieve classification using the difference in particle size between the crushed glass substrate and the crushed solar cells.

8. The method of 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 of claim 8, wherein silver and copper are concentrated from the final crushed material through a classification process.

10. The method of claim 1, wherein the amount of final crushed material entering the dry kiln in the dry kiln inlet process is calculated based on the proportion of silicon dioxide composition in the inlet flux to the melting process.

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