CN116329256B - A method for efficiently recycling waste photovoltaic modules - Google Patents

Abstract

The invention discloses a method for efficiently recycling waste photovoltaic modules, which is used for efficiently separating and recycling all parts of the waste photovoltaic modules by activating pre-soaking liquid, pre-soaking, calcining at medium and low temperature and cleaning with ethanol. The method avoids the steam type limited swelling, uses the organic solvent in the room temperature environment, realizes the high-efficiency decomposition of the organic solvent by calcining, avoids the extra cost loss and environmental pollution caused by the volatilization of the toxic solvent, and realizes the normal-pressure and normal-temperature pre-dissolution of the photovoltaic module. The method disclosed by the invention enables the waste photovoltaic module to be subjected to air combustion treatment at a lower temperature (150-450 ℃). Finally, residual EVA can be further dissolved by washing with an absolute ethyl alcohol hot solution, and pollutants formed in the combustion process can be further washed, so that the effective separation and recovery of each part of the waste photovoltaic module are realized. By the method, the highest recovery rate of the metal material in the waste photovoltaic module is 98.17%, the highest recovery rate of the crystalline silicon cell is 96.39%, and the highest recovery rate of the glass plate is 99.15%.

Description

A method for efficiently recycling waste photovoltaic modules

Technical Field

The invention belongs to the field of solid waste resource recovery, and in particular relates to a method for efficiently recovering waste photovoltaic components.

Background technique

The operating life of solar photovoltaic panels is 20 to 30 years, and by 2050, the amount of waste photovoltaic modules is expected to reach 80 million tons. At present, after the frames and junction boxes are removed from waste photovoltaic modules, the remaining photovoltaic modules are usually directly incinerated or crushed for use as fillers and aggregates. The overall recycling and resource utilization of photovoltaic modules is low, and the disposal process is also accompanied by the generation of smoke and the risk of heavy (precious) metal release. It is urgent to explore and develop photovoltaic module recycling and reuse technologies with low energy consumption, economic feasibility, and no secondary pollution. The current mainstream recycling technologies include pyrolysis, low-temperature deep-cold grinding, crushing and separation, and wet refining technology. The pyrolysis technology puts the components to be recycled into a high-temperature furnace, decomposes the organic packaging material (EVA) at high temperature, and separates the components. The pyrolysis technology is difficult to recycle the complete silicon wafer, and the recycling energy consumption is high (the temperature in the furnace must reach above 500°C), the process is cumbersome, and the high-temperature treatment process will also produce toxic and harmful gases. Grinding separation technology is relatively simple to operate and easy to build a large-scale production line, but the purity of the separated substances is not high and the recovery efficiency is low.

The existing complete silicon wafer photovoltaic module recycling technology is achieved by combining organic solvent heat treatment and high-temperature thermal decomposition. In order to effectively dissolve the EVA in the photovoltaic module, it is usually necessary to mix the organic solvent and the pressure aid, and vaporize the mixed organic solvent by heating (100-200°C), and then perform steam-limited swelling on the EVA. In general, organic solvents are usually toxic. Steam-limited swelling is not only easy to cause a large amount of organic solvent volatilization, resulting in solvent waste, but also the volatile solvent seriously pollutes the operating environment. Therefore, the organic solvent vapor generation and swelling process have extremely high requirements on the corrosion resistance, sealing and automatic control accuracy of the equipment. The supporting control console, ventilation, cooling, and air purification equipment are complex and the process chain is too long.

Summary of the invention

Purpose of the invention: The purpose of the present invention is to provide a method for pre-dissolving photovoltaic modules at normal pressure and temperature without toxic solvents, thereby reducing environmental pollution and efficiently recycling waste photovoltaic modules.

Technical solution: The method for efficiently recycling waste photovoltaic modules described in the present invention comprises the following steps:

(1) removing the aluminum frame and junction box of the discarded photovoltaic modules to obtain the photovoltaic glass panel;

(2) mixing toluene and trichloroethylene, and stirring evenly to obtain a pre-soaking solution;

(3) mixing the saturated salt solution and the pre-soaking solution to obtain a salt-doped pre-soaking solution;

(4) subjecting the salt-doped pre-soaking solution to low-temperature plasma irradiation to obtain an activated pre-soaking solution;

(5) soaking the photovoltaic glass panel obtained in step (1) in an activated pre-soaking solution at room temperature, taking out the photovoltaic glass panel, and air-drying it to obtain a pre-soaked photovoltaic panel;

(6) placing the pre-soaked photovoltaic panel in a combustion furnace for heating, taking it out, and cooling it to obtain a heated and calcined photovoltaic panel;

(7) Immersing the heated calcined photovoltaic panel in an anhydrous ethanol solution and heating it under closed conditions, taking out the solid specimen after heating, and classifying it to obtain separated metal materials, crystalline silicon cells and glass panels.

Furthermore, the mass ratio of toluene to trichloroethylene in step (2) is 5 to 25:100.

Furthermore, the saturated salt solution described in step (3) includes any one of sodium chloride and potassium chloride saturated salt solutions or a combination of both.

Furthermore, the mass ratio of the saturated salt solution to the pre-soaking solution in step (3) is 0.5 to 5.5:100.

Furthermore, the irradiation time of the low-temperature plasma irradiation treatment in step (4) is 0.5 to 4.5 hours; and the low-temperature plasma action voltage is set to 5 to 75 kV.

Furthermore, the soaking time in step (5) is 1 to 5 days.

Furthermore, the heating time in step (6) is 0.5 to 5.5 hours, and the heating temperature is 150 to 450°C.

Furthermore, the heating time in step (7) is 1 to 3 days, and the heating temperature is 60 to 120°C.

Reaction mechanism: Under the irradiation of low-temperature plasma, water molecules in saturated salt water and oxygen in the air are ionized and dissociated to generate hydroxyl radicals, oxygen radicals, and hydrogen radicals; chloride ions in saturated salt water react with hydroxyl radicals and oxygen radicals to generate chlorine radicals, chloroxy radicals, hypochlorite, chlorate, and perchlorate. Hydroxyl radicals, oxygen radicals, hydrogen radicals, chlorine radicals, chloroxy radicals, hypochlorite, chlorate, and perchlorate react with part of toluene and trichloroethylene, causing dehydrogenation and chlorination, benzene ring cleavage, and addition reactions of part of toluene and trichloroethylene, thereby realizing efficient activation of the pre-soaking liquid. The entire photovoltaic glass panel is immersed in the activation pre-soaking liquid at room temperature. The active organic substances in the activation pre-soaking penetrate into the EVA packaging material through charge balance, ion migration, local dialysis, and intercalation synergistic effects, efficiently dissolving uncross-linked EVA and partially cross-linked EVA, thereby causing the EVA structure to expand. The pre-soaked photovoltaic panel is placed in a combustion furnace for heating. Under medium-low temperature (150-450°C) heating conditions, the EVA, toluene, trichloroethylene and air in the pre-soaked photovoltaic panel react efficiently to generate carbon dioxide, chloride gas and water vapor under the synergistic effect of carbon thermal chlorination and mineralization decomposition, and the residual EVA cross-linking structure is destroyed by chloride, and the carbon chain is broken. The heated and calcined photovoltaic panel is immersed in an anhydrous ethanol solution and heated under closed conditions. The residual EVA and other organic pollutants in the heated and calcined photovoltaic panel are further dissolved into the ethanol solution, thereby realizing the effective separation and recovery of various parts of the waste photovoltaic components.

Beneficial effects: Compared with the prior art, the present invention has the following outstanding and significant advantages: the method for efficiently recycling waste photovoltaic modules provided by the present invention has a simple preparation process, and the efficient separation and recovery of various parts of the waste photovoltaic modules are achieved by activating the pre-soaking liquid, pre-soaking, medium and low temperature calcination, and ethanol cleaning. It avoids steam-type limited swelling, uses organic solvents under room temperature and realizes efficient decomposition of organic solvents by calcination, avoids the additional cost loss and environmental pollution caused by the volatilization of toxic solvents, and realizes the pre-dissolution of photovoltaic modules at normal pressure and temperature. The method of the present invention allows the waste photovoltaic modules to be treated by air combustion under lower temperature (150-450°C). Finally, by washing with anhydrous ethanol hot solution, the residual EVA and the pollutants formed in the cleaning combustion process can be further dissolved, thereby realizing the effective separation and recovery of various parts of the waste photovoltaic modules. Through the method of the present invention, the maximum recovery rate of metal materials in waste photovoltaic modules is 98.17%, the maximum recovery rate of crystalline silicon cells is 96.39%, and the maximum recovery rate of glass plates is 99.15%.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a flow chart of the preparation method of the present invention.

Detailed ways

The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

Example 1 Effect of the mass ratio of toluene and trichloroethylene on the recovery efficiency of metal materials, crystalline silicon cells and glass plates in waste photovoltaic modules

The aluminum frame and junction box of the discarded photovoltaic module are removed to obtain a photovoltaic glass panel. Toluene and trichloroethylene are weighed in a mass ratio of 2:100, 3:100, 4:100, 5:100, 15:100, 25:100, 30:100, 35:100, and 40:100, respectively, mixed, and stirred evenly to obtain a pre-soaking solution. Saturated salt solution and pre-soaking solution are mixed in a mass ratio of 0.5:100 to obtain a salt-doped pre-soaking solution, wherein the saturated salt solution is a saturated salt solution of sodium chloride. The salt-doped pre-soaking solution is subjected to low-temperature plasma irradiation for 0.5 hours to obtain an activated pre-soaking solution, wherein the low-temperature plasma action voltage is set to 5kV. The photovoltaic glass panel is soaked in the activated pre-soaking solution for 1 day at room temperature, the photovoltaic glass panel is taken out, and air-dried to obtain a pre-soaked photovoltaic panel. The pre-soaked photovoltaic panel is placed in a combustion furnace and heated for 0.5 hours, taken out, and cooled to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 150°C. The heated calcined photovoltaic panel was immersed in an anhydrous ethanol solution and heated under closed conditions for 1 day, wherein the heating temperature was 60° C. The solid test pieces were taken out and classified to obtain separated metal materials, crystalline silicon cells and glass panels.

Calculation of recycling rate of metal materials, crystalline silicon cells and glass panels: The recycling rate of metal materials, crystalline silicon cells and glass panels is calculated according to formula (1), where _δi is the recycling efficiency of metal materials, crystalline silicon cells or glass panels, _m0i is the mass of the original metal materials, crystalline silicon cells or glass panels in the photovoltaic module, and _mti is the mass of the corresponding recycled metal materials, crystalline silicon cells or glass panels.

The test results of this embodiment are shown in Table 1.

Table 1 Effect of the mass ratio of toluene and trichloroethylene on the recovery efficiency of metal materials, crystalline silicon cells and glass panels in waste photovoltaic modules

As shown in Table 1, when the mass ratio of toluene to trichloroethylene is less than 5:100 (such as in Table 1, the mass ratio of toluene to trichloroethylene = 4:100, 3:100, 2:100 and lower ratios not listed in Table 1), less toluene is added, which makes the swelling performance of the prepared activated pre-soaking liquid EVA worse, resulting in the recycling efficiency of metal materials, crystalline silicon cells and glass plates in the waste photovoltaic modules significantly reduced as the mass ratio of toluene to trichloroethylene decreases. When the mass ratio of toluene to trichloroethylene is equal to 5-25:100 (such as in Table 1, the mass ratio of toluene to trichloroethylene = 5:100, 15:100, 25:100), the photovoltaic glass whole plate is immersed in the activated pre-soaking liquid at room temperature, and the active organic matter in the activated pre-soaking penetrates into the EVA packaging material through charge balance, ion migration and local dialysis, intercalation synergistic action, and efficiently dissolves the uncross-linked EVA and partially cross-linked EVA, thereby causing the EVA structure to expand. Finally, the recovery rate of metal materials in waste photovoltaic modules is higher than 85%, the recovery rate of crystalline silicon cells is higher than 83%, and the recovery efficiency of glass plates is higher than 86%. When the mass ratio of toluene and trichloroethylene is greater than 25:100 (such as in Table 1, the mass ratio of toluene and trichloroethylene = 30:100, 35:100, 40:100 and higher ratios not listed in Table 1), too much toluene is added, the synergistic effect of toluene and trichloroethylene deteriorates, and the swelling performance of the prepared activated pre-soaking liquid EVA deteriorates, resulting in the recovery efficiency of metal materials, crystalline silicon cells, and glass plates in waste photovoltaic modules significantly decreasing as the mass ratio of toluene and trichloroethylene further increases. Therefore, in general, combined with efficiency and cost, when the mass ratio of toluene and trichloroethylene is equal to 5 to 25:100, it is most conducive to improving the recovery efficiency of metal materials, crystalline silicon cells, and glass plates.

Example 2 Effect of pre-soaked photovoltaic panel combustion heating time on the recovery efficiency of metal materials, crystalline silicon cells and glass panels in discarded photovoltaic modules

Remove the aluminum frame and junction box from the discarded photovoltaic module to obtain a photovoltaic glass panel. Weigh toluene and trichloroethylene according to a mass ratio of 25:100, mix and stir evenly to obtain a pre-soaking solution. Mix the saturated salt solution and the pre-soaking solution according to a mass ratio of 3:100 to obtain a salt-doped pre-soaking solution, wherein the saturated salt solution is a saturated salt solution of sodium chloride. The salt-doped pre-soaking solution is subjected to low-temperature plasma irradiation for 2.5 hours to obtain an activated pre-soaking solution, wherein the low-temperature plasma action voltage is set to 40kV. Soak the photovoltaic glass panel in the activated pre-soaking solution for 3 days at room temperature, take out the photovoltaic glass panel, air-dry, and obtain a pre-soaked photovoltaic panel. The pre-soaked photovoltaic panel is placed in a combustion furnace and heated for 0.25 hours, 0.3 hours, 0.4 hours, 0.5 hours, 3 hours, 5.5 hours, 6 hours, 6.5 hours, and 7 hours, taken out, and cooled to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 300°C. The heated calcined photovoltaic panel was immersed in an anhydrous ethanol solution and heated for 2 days under closed conditions, wherein the heating temperature was 90° C. The solid specimens were taken out and classified to obtain separated metal materials, crystalline silicon cells and glass panels.

The calculation of the recovery rate of metal materials, crystalline silicon cells and glass plates is the same as in Example 1. The test results of this example are shown in Table 2. Table 2 Effect of pre-soaked photovoltaic panel combustion heating time on the recovery efficiency of metal materials, crystalline silicon cells and glass plates in discarded photovoltaic modules

As shown in Table 2, when the pre-soaked photovoltaic panel combustion heating time is less than 0.5 hours (such as in Table 2, the pre-soaked photovoltaic panel combustion heating time = 0.4 hours, 0.3 hours, 0.25 hours and lower values not listed in Table 2), the pre-soaked photovoltaic panel combustion heating time is short, and the residual EVA cross-linked structure is poorly destroyed, resulting in the metal materials, crystalline silicon cells, and glass plate recovery efficiencies in the discarded photovoltaic components being significantly reduced as the pre-soaked photovoltaic panel combustion heating time decreases. When the pre-soaked photovoltaic panel combustion heating time is equal to 0.5 to 5.5 hours (such as in Table 2, the pre-soaked photovoltaic panel combustion heating time = 0.5 hours, 3 hours, 5.5 hours), the pre-soaked photovoltaic panel is placed in a combustion furnace for heating. Under medium and low temperature (150 to 450°C) heating conditions, EVA, toluene, trichloroethylene and air in the pre-soaked photovoltaic panel react efficiently to generate carbon dioxide, chloride gas and water vapor under the synergistic effect of carbon thermal chlorination and mineralization decomposition, and the residual EVA cross-linked structure is destroyed by chlorides, and the carbon chain is broken. Finally, the recovery rates of metal materials in waste photovoltaic modules are all higher than 92%, the recovery rates of crystalline silicon cells are all higher than 89%, and the recovery efficiencies of glass panels are all higher than 94%. When the combustion and heating time of the pre-soaked photovoltaic panels is greater than 5.5 hours (as in Table 2, the combustion and heating time of the pre-soaked photovoltaic panels = 6.0 hours, 6.5 hours, 7.0 hours, and higher values not listed in Table 2), the combustion and heating time of the pre-soaked photovoltaic panels is too long, and chlorine and oxygen corrosion is significant, resulting in the recovery efficiencies of metal materials, crystalline silicon cells, and glass panels in waste photovoltaic modules being significantly reduced as the combustion and heating time of the pre-soaked photovoltaic panels further increases. Therefore, in general, combining efficiency and cost, when the combustion and heating time of the pre-soaked photovoltaic panels is equal to 0.5 to 5.5 hours, it is most conducive to improving the recovery efficiency of metal materials, crystalline silicon cells, and glass panels.

Example 3 Effect of the heating temperature of anhydrous ethanol solution on the recovery efficiency of metal materials, crystalline silicon cells and glass plates in discarded photovoltaic modules

Remove the aluminum frame and junction box from the discarded photovoltaic modules to obtain a whole photovoltaic glass panel. Weigh toluene and trichloroethylene according to a mass ratio of 25:100, mix and stir evenly to obtain a pre-soaking solution. Mix the saturated salt solution and the pre-soaking solution according to a mass ratio of 5.5:100 to obtain a salt-doped pre-soaking solution, wherein the saturated salt solution is a saturated salt solution of sodium chloride. The salt-doped pre-soaking solution is subjected to low-temperature plasma irradiation for 4.5 hours to obtain an activated pre-soaking solution, wherein the low-temperature plasma action voltage is set to 75kV. Soak the whole photovoltaic glass panel in the activated pre-soaking solution for 5 days at room temperature, take out the whole photovoltaic glass panel, air-dry, and obtain a pre-soaked photovoltaic panel. Place the pre-soaked photovoltaic panel in a combustion furnace and heat for 5.5 hours, take it out and cool it to obtain a heated and calcined photovoltaic panel, wherein the heating temperature is 450°C. The heated calcined photovoltaic panel was immersed in an anhydrous ethanol solution and heated under closed conditions for 3 days, wherein the heating temperatures were 30°C, 40°C, 50°C, 60°C, 90°C, 120°C, 130°C, 140°C, and 150°C. The solid specimens were taken out and classified to obtain separated metal materials, crystalline silicon cells, and glass plates.

The calculation of the recovery rate of metal materials, crystalline silicon cells and glass plates is the same as in Example 1. The test results of this example are shown in Table 3. Table 3 Effect of the heating temperature of anhydrous ethanol solution on the recovery efficiency of metal materials, crystalline silicon cells and glass plates in waste photovoltaic modules

As shown in Table 3, when the heating temperature of the anhydrous ethanol solution is less than 60°C (as in Table 3, the heating temperature of the anhydrous ethanol solution = 50°C, 40°C, 30°C and lower values not listed in Table 3), the heating temperature is too low, and the dissolution effect of the residual EVA and other organic pollutants in the heating and calcining photovoltaic panels becomes poor, resulting in the metal materials, crystalline silicon cells, and glass plate recovery efficiencies in the waste photovoltaic modules being significantly reduced as the heating temperature of the anhydrous ethanol solution decreases. When the heating temperature of the anhydrous ethanol solution is equal to 60-120°C (as in Table 3, the heating temperature of the anhydrous ethanol solution = 60°C, 90°C, 120°C), the residual EVA and other organic pollutants in the heating and calcining photovoltaic panels are further dissolved in the ethanol solution, thereby achieving effective separation and recovery of various parts of the waste photovoltaic modules. Finally, the recovery rate of metal materials in the waste photovoltaic modules is higher than 94%, the recovery rate of crystalline silicon cells is higher than 91%, and the recovery efficiency of glass plates is higher than 95%. When the heating temperature of the anhydrous ethanol solution is greater than 120°C (as in Table 3, the heating temperature of the anhydrous ethanol solution = 130°C, 140°C, 150°C and higher values not listed in Table 3), the heating temperature is too high, and the volatilization and escape ability of the anhydrous ethanol are enhanced, resulting in a slight decrease in the recycling efficiency of metal materials, crystalline silicon cells, and glass panels in the discarded photovoltaic modules as the combustion heating time of the pre-soaked photovoltaic panels increases. Therefore, in general, combining efficiency and cost, when the heating temperature of the anhydrous ethanol solution is equal to 60-120°C, it is most conducive to improving the recycling efficiency of metal materials, crystalline silicon cells, and glass panels.

Example 4 Effect of the type of saturated salt solution on the recovery efficiency of metal materials, crystalline silicon cells and glass panels in discarded photovoltaic modules

Remove the aluminum frame and junction box from the discarded photovoltaic module to obtain a photovoltaic glass panel. Weigh toluene and trichloroethylene according to a mass ratio of 25:100, mix and stir evenly to obtain a pre-soak solution. Mix the saturated salt solution and the pre-soak solution according to a mass ratio of 5.5:100 to obtain a salt-doped pre-soak solution, wherein the saturated salt solution is a saturated solution of sodium chloride, a saturated salt solution of potassium chloride, and a mixed saturated solution of sodium chloride and potassium chloride (50% sodium chloride + 50% potassium chloride). The salt-doped pre-soak solution is subjected to low-temperature plasma irradiation for 4.5 hours to obtain an activated pre-soak solution, wherein the low-temperature plasma action voltage is set to 75kV. Soak the photovoltaic glass panel in the activated pre-soak solution for 5 days at room temperature, take out the photovoltaic glass panel, air-dry, and obtain a pre-soaked photovoltaic panel. The pre-soaked photovoltaic panel is placed in a combustion furnace and heated for 5.5 hours, taken out and cooled to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 450°C. The heated calcined photovoltaic panel was immersed in an anhydrous ethanol solution and heated for 3 days under closed conditions, wherein the heating temperature was 120° C. The solid specimens were taken out and classified to obtain separated metal materials, crystalline silicon cells and glass panels.

The calculation of the recovery rate of metal materials, crystalline silicon cells and glass plates is the same as in Example 1. The test results of this example are shown in Table 4.

Table 4 Effect of saturated salt solution types on the recovery efficiency of metal materials, crystalline silicon cells and glass panels in discarded photovoltaic modules

It can be seen from Table 4 that when the saturated salt solution is a saturated sodium chloride solution, a saturated potassium chloride salt solution, and a mixed saturated solution of sodium chloride and potassium chloride, the recovery efficiencies of metal materials, crystalline silicon cells, and glass panels in discarded photovoltaic modules are relatively close, with no significant differences.

Comparative study on the effects of different comparative processes on the recycling efficiency of metal materials, crystalline silicon cells and glass panels in waste photovoltaic modules

The process of the present invention is as follows: the aluminum frame and the junction box of the discarded photovoltaic module are removed to obtain a photovoltaic glass whole plate. Toluene and trichloroethylene are weighed respectively according to a mass ratio of 25:100, mixed, and stirred evenly to obtain a pre-soaking solution. The saturated salt solution and the pre-soaking solution are mixed according to a mass ratio of 5.5:100 to obtain a salt-doped pre-soaking solution, wherein the saturated salt solution is a saturated sodium chloride solution. The salt-doped pre-soaking solution is subjected to low-temperature plasma irradiation treatment for 4.5 hours to obtain an activated pre-soaking solution, wherein the low-temperature plasma action voltage is set to 75kV. The photovoltaic glass whole plate is soaked in the activated pre-soaking solution for 5 days at room temperature, the photovoltaic glass whole plate is taken out, and air-dried to obtain a pre-soaked photovoltaic panel. The pre-soaked photovoltaic panel is placed in a combustion furnace and heated for 5.5 hours, taken out, and cooled to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 450°C. The heated calcined photovoltaic panel is immersed in an anhydrous ethanol solution, heated under closed conditions for 3 days, wherein the heating temperature is 120°C, the solid specimen is taken out, and classified to obtain separated metal materials, crystalline silicon cells and glass panels.

Comparative process 1: Remove the aluminum frame and junction box from the discarded photovoltaic modules to obtain a whole photovoltaic glass panel. Weigh toluene and trichloroethylene at a mass ratio of 25:100, mix and stir evenly to obtain a pre-soaking solution. Mix the saturated salt solution and the pre-soaking solution at a mass ratio of 5.5:100 to obtain a salt-doped pre-soaking solution, wherein the saturated salt solution is a saturated sodium chloride solution. Soak the whole photovoltaic glass panel in the salt-doped pre-soaking solution for 5 days at room temperature, take out the whole photovoltaic glass panel, air-dry it, and obtain a pre-soaked photovoltaic panel. Place the pre-soaked photovoltaic panel in a combustion furnace and heat it for 5.5 hours, take it out and cool it to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 450°C. Immerse the heated calcined photovoltaic panel in an anhydrous ethanol solution and heat it under closed conditions for 3 days, wherein the heating temperature is 120°C, take out the solid test piece, classify it, and obtain separated metal materials, crystalline silicon cells and glass panels.

Process 2 of the present invention: remove the aluminum frame and junction box of the discarded photovoltaic assembly to obtain a whole photovoltaic glass panel. Weigh toluene and trichloroethylene according to a mass ratio of 25:100, mix and stir evenly to obtain a pre-soaking solution. The pre-soaking solution is subjected to low-temperature plasma irradiation treatment for 4.5 hours to obtain an activated pre-soaking solution, wherein the low-temperature plasma action voltage is set to 75kV. Soak the whole photovoltaic glass panel in the activated pre-soaking solution for 5 days at room temperature, take out the whole photovoltaic glass panel, air-dry, and obtain a pre-soaked photovoltaic panel. Place the pre-soaked photovoltaic panel in a combustion furnace and heat it for 5.5 hours, take it out and cool it to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 450°C. Immerse the heated calcined photovoltaic panel in an anhydrous ethanol solution and heat it under closed conditions for 3 days, wherein the heating temperature is 120°C, take out the solid test piece, classify it, and obtain separated metal materials, crystalline silicon cells and glass panels.

Comparative process 3: Remove the aluminum frame and junction box from the discarded photovoltaic module to obtain a photovoltaic glass panel. Weigh toluene and trichloroethylene at a mass ratio of 25:100, mix and stir evenly to obtain a pre-soak solution. Mix the saturated salt solution and the pre-soak solution at a mass ratio of 5.5:100 to obtain a salt-doped pre-soak solution, wherein the saturated salt solution is a saturated sodium chloride solution. The salt-doped pre-soak solution is subjected to low-temperature plasma irradiation for 4.5 hours to obtain an activated pre-soak solution, wherein the low-temperature plasma action voltage is set to 75kV. Soak the photovoltaic glass panel in the activated pre-soak solution for 5 days at room temperature, take out the photovoltaic glass panel, air-dry, and obtain a pre-soaked photovoltaic panel. Place the pre-soaked photovoltaic panel in a combustion furnace and heat it for 5.5 hours, take it out and cool it to obtain a heated calcined photovoltaic panel, wherein the heating temperature is 450°C. Immerse the heated calcined photovoltaic panel in water and heat it under closed conditions for 3 days, wherein the heating temperature is 120°C, take out the solid specimen, classify it, and obtain separated metal materials, crystalline silicon cells and glass panels.

The calculation of the recovery rates of metal materials, crystalline silicon cells and glass plates is the same as in Example 1. The test results of this example are shown in Table 5.

Table 5 Effects of different comparative processes on the recycling efficiency of metal materials, crystalline silicon cells and glass panels in waste photovoltaic modules

Process Type _{δMetal Materials} Delta _{Crystal Static Cell} Delta _{glass plate} Process of the present invention 98.17% 96.39% 99.15% Comparison process 1 56.74% 49.36% 52.61% Comparison process 2 42.17% 45.14% 47.63% Comparison process 3 40.65% 44.85% 43.92%

It can be seen from Table 5 that the metal material, crystalline silicon cell and glass plate recycling efficiency achieved by the process of the present invention is much higher than that of Comparative Process 1, Comparative Process 2 and Comparative Process 3.

Claims (7)

1. The method for efficiently recycling the waste photovoltaic modules is characterized by comprising the following steps of:

(1) Removing the aluminum frame and the junction box of the waste photovoltaic module to obtain a photovoltaic glass whole plate;

(2) Mixing toluene and trichloroethylene, and uniformly stirring to obtain a pre-soaking solution;

(3) Mixing the saturated salt solution with the presoaking liquid to obtain salt-doped presoaking liquid;

The saturated salt solution comprises any one or the combination of two of sodium chloride and potassium chloride saturated salt solutions;

(4) Performing low-temperature plasma irradiation treatment on the salt doped pre-soaking solution to obtain an activated pre-soaking solution;

(5) Soaking the whole photovoltaic glass plate obtained in the step (1) in an activation pre-soaking solution at room temperature, taking out the whole photovoltaic glass plate, and air-drying to obtain a pre-soaking photovoltaic plate;

(6) Heating the presoaked photovoltaic panel in a combustion furnace, taking out, and cooling to obtain a heated calcined photovoltaic panel;

(7) Immersing the heated calcined photovoltaic panel in absolute ethanol solution, heating under a closed condition, taking out a solid test piece after heating, and classifying to obtain a separated metal material, a crystalline silicon battery and a glass plate.

2. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the mass ratio of toluene to trichloroethylene in the step (2) is 5-25:100.

3. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the mass ratio of the saturated salt solution to the presoaked liquid in the step (3) is 0.5-5.5:100.

4. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the irradiation time of the low-temperature plasma irradiation treatment in the step (4) is 0.5-4.5 hours; the action voltage of the low-temperature plasma is set to be 5-75 kV.

5. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the soaking time in the step (5) is 1-5 days.

6. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the heating time in the step (6) is 0.5-5.5 hours, and the heating temperature is 150-450 ℃.

7. The method for efficiently recycling waste photovoltaic modules according to claim 1, wherein the heating time in the step (7) is 1-3 days, and the heating temperature is 60-120 ℃.