Method for recycling waste solar panels

Abstract

According to one embodiment of the present invention, a method for recovering a waste solar panel, the waste solar panel comprises a glass substrate, a solar cell, an adhesive layer arranged between the glass substrate and the solar cell to joint the glass substrate and the solar cell, and a metal frame configured to fix a laminated structure of the glass substrate, the adhesive layer and the solar cell, the method comprises: a first crushing process of crushing the waste solar panel to a predetermined size or less; a frame removal process of sorting and removing a metal frame contained in the first crushing material crushed by the first crushing process; a second crushing process of crushing the first crushing material from which the metal frame has been removed by the frame removal process to a predetermined size or less; a roasting process of removing an adhesive layer between the glass substrate and the solar cell by feeding a second crushing material crushed by the second crushing process into a roasting furnace and heating the second crushing material; a classification process of separating the second crushed material subjected to the roasting process into a glass substrate and a solar cell and removing the glass substrate; and a drying furnace feeding process of feeding the final crushed material from which the glass substrate has been removed to a drying furnace of the smelting process.

Description

Technical Field

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

[0002] Solar power generation, a renewable energy source, has attracted considerable attention due to its low environmental impact, driven by its use of clean sunlight. A solar panel used for this type of power generation consists of a glass substrate, solar cells, an adhesive layer, such as ethylene vinyl acetate (EVA), positioned between the solar cells and the glass substrate to bond the two, and an aluminum frame that secures the glass substrate, adhesive layer, and solar cells together into a module.

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

[0004] As the distribution of solar power generation systems expands, the number of used solar panels that have reached the end of their lifespan is expected to increase exponentially. Considering that the lifespan of a solar panel is approximately 25 years, as solar panels that have been installed since the early 2000s are approaching the end of their lifespan, a large number of discarded solar panels are expected to begin to appear from the mid-to-late 2020s. Therefore, various methods are being sought for the disposal of discarded solar panels. However, to date, all discarded solar panels have been buried without recycling, or only the aluminum frames have been separated and recycled, and complete recycling of discarded solar modules has not yet been achieved. Specifically, the current existing method for processing discarded solar panels is to manually separate the aluminum frames and glass for sale, and bury the remaining parts of the solar cells. Some companies have tried to use machinery to semi-automate and automate the process of separating the aluminum frames and glass, but most of them are small companies with low processing capacity.

[0005] Solar cells, which are silicon-rich and contain significant amounts of copper and silver, are particularly difficult to recycle, requiring complex processes to separate valuable metals through conventional crushing and sorting methods. Therefore, there is a need to develop a recycling method that can address this issue, as well as an automated process capable of processing large numbers of solar panels. Summary of the Invention

[0006] Technical issues

[0007] The present disclosure provides a method for replacing flux made of silicon dioxide (SiO2) used in a smelting process with waste solar panels by feeding the waste solar panels into a smelting furnace performing a smelting process to recover valuable metals.

[0008] Solution to the problem

[0009] Furthermore, the present disclosure provides a method for recovering valuable metal-rich materials from discarded solar panels.

[0010] According to one embodiment of the present invention, a method for recycling waste solar panels includes a glass substrate, a solar cell, an adhesive layer arranged between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame configured to fix the stacked structure of the glass substrate, the adhesive layer, and the solar cell. The method includes: a first crushing process for crushing the waste solar panel to a predetermined size or smaller; a frame removal process for sorting and removing the metal frame contained in the first crushed material crushed by the first crushing process; a second crushing process for crushing the first crushed material from which the metal frame has been removed by the frame removal process to a predetermined size or smaller; a firing process for removing the adhesive layer between the glass substrate and the solar cell by feeding the second crushed material crushed by the second crushing process into a firing furnace and heating the second crushed material; a sorting process for separating the second crushed material that has undergone the firing process into a glass substrate and a solar cell, and removing the glass substrate; and a drying furnace feeding process for feeding the final crushed material from which the glass substrate has been removed into a drying furnace for a melting process.

[0011] In the first crushing process, the waste solar panels are 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.

[0012] The first crushing process and the second crushing process are performed by the 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 are discharged through a screen provided at the bottom of the crusher.

[0013] The metal frame is made of aluminum and the frame removal process is performed by means of an eddy current separator.

[0014] The calcination process is performed at a temperature of 500 to 600 degrees Celsius for 2 to 3 hours.

[0015] The adhesive layer is made of ethylene vinyl acetate (EVA), and the EVA is removed by burning or sublimation during the firing process.

[0016] The classification process is performed by sieving classification using the difference in particle size between the crushed glass substrates and the crushed solar cells.

[0017] The final crushed material from which the glass substrate has been removed contains silicon (Si), silver (Ag), and copper (Cu).

[0018] Silver and copper are concentrated from the final crushed material through a sorting process.

[0019] The amount of the final crushed material fed to the drying furnace in the drying furnace feeding process was calculated based on the composition ratio of silica in the flux fed to the smelting process.

[0020] Effects of the Invention

[0021] According to the present disclosure, recycled foundry sand (including SiO 2 ) fed as one of the fluxes in the smelting process can be replaced with discarded solar panels.

[0022] In addition, valuable metals such as silver and copper contained in discarded solar panels can be concentrated and recovered. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The present invention is a process flow chart of a method for recycling waste solar panels according to an embodiment of the present invention. DETAILED DESCRIPTION

[0024] In describing the present disclosure, when a related known function is considered obvious to those skilled in the art and a detailed description of the function unnecessarily obstructs the gist of the present disclosure, the detailed description will be omitted.

[0025] This disclosure relates to a method for recycling discarded solar panels using an existing smelting process. The recycling method primarily utilizes discarded solar panels, but is not necessarily limited thereto. The method is also applicable to all industrial waste containing silicon and valuable metals.

[0026] The present disclosure provides a method for processing waste solar panels and feeding the processed waste solar panels into a drying furnace for a traditional smelting process, thereby replacing silicon dioxide fed into the smelting process and recovering valuable metals contained in the waste solar panels.

[0027] Figure 1 The present invention is a process flow chart of a method for recycling waste solar panels according to an embodiment of the present invention.

[0028] The waste solar panels to be recycled in the present disclosure include a glass substrate, a solar cell, an adhesive layer disposed between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame configured to fix the stacked structure of the glass substrate, the adhesive layer, and the solar cell and disposed at the peripheral edge of the solar panel.

[0029] Reference Figure 1, waste solar panels are fed into a crusher, and the crusher crushes the waste solar panels to a size of 150 mm or less (first crushing process S1). The crusher is used to perform the first crushing process S1, wherein the waste solar panels are crushed to a size of 150 mm or less by the first crushing process S1, and the crushed waste solar panels are discharged as the first crushed material through a screen provided at the bottom of the crusher. Any mechanism capable of crushing glass substrates, solar cells, metal frames, etc. contained in the waste solar panels 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.

[0030] The first crushed material crushed by the first crushing process S1 is transported to the 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 obtained by crushing the discarded solar panels contains a metal frame material that maintains the stacking structure of the discarded solar panels, and the metal frame may be made of aluminum. The first crushed material containing the crushed aluminum frame is transported 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 with a strong magnetic field to be able to sort and separate the aluminum component contained in the first crushed material.

[0031] The first crushed material, from which the aluminum frame has been removed in 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 performed using a crusher, wherein the discarded solar panels are crushed to a size of 50 mm or less in the second crushing process S3, and the first crushed material is discharged through a screen installed at the bottom of the crusher as the second crushed material. The second crushing process S3 can be performed in the same manner as the first crushing process S1. By appropriately adjusting the number of crusher blades, blade gap, blade speed, etc., the first crushed material can be crushed to a size (50 mm or less) smaller than the target crushing size (150 mm or less) in the first crushing process S1.

[0032] The second crushed material from the second crushing process S3 is fed into a firing process S4. In 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. The adhesive layer can be made of ethylene vinyl acetate (EVA). Firing process S4 can be performed in a firing furnace at a temperature of 500 to 600 degrees Celsius for 2 to 3 hours. Firing process S4 removes the EVA adhesive layer between the glass substrate and the solar cell from the second crushed material by combustion or sublimation. Upon completion of firing process S4, the adhesive layer is removed, leaving only the crushed glass substrate and the solar cell. In particular, the high temperature firing process maintains the solar cell in a powdered form, while the crushed glass substrate has a particle size similar to that before entering the firing furnace.

[0033] The second crushed material that has passed the baking 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 the classification process S5. After the baking process S4, the classification process S5 can be performed by screening and classification using the difference in particle size between the glass substrates and solar cells contained in the second crushed material. After the baking process S4, the second crushed material contains solar cells in powder form and glass substrates with a larger particle size than the solar cells. Therefore, 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 are the final crushed material and may contain silicon (Si), silver (Ag), copper (Cu), etc.

[0034] As described above, by removing the glass substrate, resin, and other impurities through the classification process S5 , valuable metals such as silver and copper contained in the solar cell can be concentrated.

[0035] The final crushed material, from which the glass substrates have been removed in the sorting process S5, is fed into the drying furnace of the smelting process (drying furnace feeding process S6). This allows valuable metals (such as silver and copper) to be recovered from discarded solar panels by recycling the final crushed material containing silicon (Si), silver (Ag), and copper (Cu) as flux and fuel for the smelting process. It also significantly reduces the amount of flux and fuel fed into the smelting process.

[0036] Specifically, flux is added to the smelting process to increase the fluidity of the melt, and this addition is even more essential when using metal scrap as the raw material. This is because natural ores contain significant amounts of flux components, such as SiO2 and Al2O3, which are not present in sufficient quantities in metal scrap. Therefore, flux addition is essential in the metal scrap smelting process. Previously, sand or recycled foundry sand was primarily used as a silicon dioxide (SiO2) flux. In the present disclosure, the final crushed material obtained from discarded solar panels, containing silicon (Si), silver (Ag), copper (Cu), and other materials, is fed into the drying furnace of the smelting process. In the drying furnace, silicon (Si), the primary component of the final crushed material, reacts with oxygen to form silicon dioxide (SiO2), which acts as the flux. This means that by feeding waste solar panels into a smelting furnace that performs a smelting process to recover valuable metals, the flux made of silicon dioxide (SiO2) fed into the smelting process can be replaced by recycling the waste solar panels. The amount of final crushed material fed into the drying furnace in the drying furnace feeding process S6 can be calculated based on the composition ratio of silicon dioxide in the flux fed into the smelting process.

[0037] Although the present disclosure has been described with respect to certain embodiments thereof, it is understood that various modifications and variations can be made without departing from the spirit and scope of the present disclosure, which may be apparent to one skilled in the art. Furthermore, such modifications and variations should be considered to be within the scope of the appended claims.

Claims

1. A method for recycling discarded solar panels, the discarded solar panels comprising a glass substrate, a solar cell, an adhesive layer disposed between the glass substrate and the solar cell to bond the glass substrate and the solar cell, and a metal frame configured to secure the stacked structure of the glass substrate, the adhesive layer, and the solar cell, the method comprising: a first crushing process of crushing the discarded solar panels to a predetermined size or smaller; a frame removing process for sorting and removing the metal frame contained in the first crushed material crushed by the first crushing process; a second crushing process of crushing the first crushed material, from which the metal frame has been removed by the frame removing process, into a predetermined size or smaller; a firing process of removing the adhesive layer between the glass substrate and the solar cell by feeding the second crushed material crushed by the second crushing process into a firing furnace and heating the second crushed material; a sorting process of separating the second crushed material that has undergone the firing process into the glass substrate and the solar cell, and removing the glass substrate; as well as A drying furnace feeding process in which the final crushed material from which the glass substrate has been removed is fed to a drying furnace of a melting process.

2. The method according to claim 1, wherein In the first crushing process, the waste solar panels are 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 according to claim 2, wherein the first crushing process and the second crushing process are performed by 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 are discharged through a screen provided at the bottom of the crusher. 4 . The method according to claim 1 , wherein the metal frame is made of aluminum, and the frame removal process is performed by an eddy current separator. The method according to claim 1 , wherein the calcination process is performed at a temperature of 500° C. to 600° C. for 2 to 3 hours.

6. The method according to 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 the firing process. 7 . The method according to claim 1 , wherein the classification process is performed by sieving classification using a particle size difference between the crushed glass substrate and the crushed solar cells. 8 . The method 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 of claim 8, wherein the silver and the copper are concentrated from the final crushed material by the classification process.

10. The method of claim 1, wherein the amount of the final crushed material fed to the drying furnace in the drying furnace feeding process is calculated based on a composition ratio of silicon dioxide in a flux fed to the smelting process.

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