Composite solution for dissolving silver in waste photovoltaic cell module and dissolving method

Abstract

The invention discloses a composite solution for dissolving silver in a waste photovoltaic cell module and a dissolving method. The composite solution comprises acid, an oxidizing agent for oxidizing a silver simple substance into silver ions and a complexing agent for complexing the silver ions. According to the method, high-efficiency leaching of the low-grade silver in the crystalline silicon battery is realized through a reaction of combining oxidation, complexing and an acid leaching system.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste treatment, and in particular to a composite solution and a dissolving method for dissolving silver in waste photovoltaic cell components. Background Art

[0002] Discarded photovoltaic cells have become the fastest growing "electronic waste". The photovoltaic market began to explode in 2000, and its lifespan is generally 25-30 years. By the end of 2020, the cumulative scrap volume of photovoltaic modules in my country is expected to exceed 2 million kilowatts, or about 160,000 tons. By 2025-2030, the amount of waste in my country will reach 1.5 million tons, about 7 million tons in 2040, and 20 million tons in 2050. The disposal of discarded photovoltaic modules has become a potential crisis in the photovoltaic field. Studies have shown that the leaching concentration of Pb in polycrystalline silicon solar cells exceeds the identification standard by 6.65 times, and the leaching concentration of Pb in monocrystalline silicon solar cells exceeds the identification standard by 2.5 times. Therefore, many EU countries have listed it as hazardous waste. If it is not properly handled, it will not only cause huge waste, but also seriously pollute the environment.

[0003] Photovoltaic modules are composed of aluminum frames, glass, EVA film, crystalline silicon cells, and TPT backplanes. They contain a variety of valuable metals and polymer functional materials, and have extremely high resource recovery value. Taking the photovoltaic industry as an example, the proportion of glass, aluminum, and semiconductor materials in crystalline silicon photovoltaic modules can reach 92%. In addition, it also contains about 1% of precious metals such as silver, about 6% of EVA, and about 3% of TPT. If all can be recycled, it will have extremely high economic value. By 2030, 1.45 million tons of carbon steel, 1.1 million tons of glass, 540,000 tons of plastic, 260,000 tons of aluminum, 170,000 tons of copper, 50,000 tons of silicon, and 550 tons of silver and other metal resources can be obtained from discarded photovoltaic modules. Although the proportion of silver electrodes is low, accounting for only 0.06%-0.1%, its value accounts for about 27%, so the economic benefits of low-cost silver recycling are great.

[0004] The silver electrode and the crystalline silicon carrier in the crystalline silicon solar cell are sintered at high temperature to form a bond between the silver and n + Ti Ag and Ag2Si2O5 are generated at the silicon interface to prevent silver from diffusing into silicon and forming ohmic contact. Silver and crystalline silicon cannot be separated by physical methods. Since the silver in crystalline silicon cells exists in elemental silver and compound silver, and silver is an extremely inert metal, it is extremely difficult to separate silver from crystalline silicon by leaching. For failed batteries, precious metal silver is separated and purified to obtain crystalline silicon and high-purity silver, which greatly improves the economic benefits of the materials. Therefore, the development of efficient silver-silicon separation technology is of great significance for the recycling of waste photovoltaics.

[0005] CN110512079A discloses a method for separating silver electrodes of crystalline silicon cells, which uses hydrofluoric acid to react with the cell to dissolve silicon so as to peel off silver from the cell, and then obtains silver electrodes through filtration and sorting. This method can obtain silver. The document uses hydrofluoric acid to corrode the crystalline silicon carrier to achieve silver electrode peeling, which will cause the loss of crystalline silicon; on the other hand, it is suitable for separating silver electrodes in complete cell sheets, but is not suitable for recovering silver from cell sheets obtained by physical crushing or pulverization separation methods, and the fluorine-containing solution is difficult to handle and causes serious pollution. Summary of the invention

[0006] In view of this, the main purpose of the present invention is to provide a composite solution and a dissolution method for dissolving silver in waste photovoltaic cell components. The present invention can achieve efficient leaching of silver in crystalline silicon cells.

[0007] To achieve the above-mentioned purpose, the first aspect of the present invention provides a composite solution for dissolving silver in waste photovoltaic cell assemblies, wherein the composite solution comprises an acid, an oxidant for oxidizing silver into silver ions, and a complexing agent for complexing silver ions.

[0008] Furthermore, the oxidant is added in the form of an oxidant solution, and the mass concentration (w%) of the oxidant in the composite solution is 0.25%-5%, preferably 2.5%-5%; preferably, the oxidant is selected from one of H2O2, butanone peroxide, benzoyl peroxide or a mixture thereof.

[0009] Furthermore, the solvent in the oxidant solution is selected from one or more of water, isopropanol and monoethanolamine.

[0010] Furthermore, the oxidant solution is a mixture solution of butanone peroxide and benzoyl peroxide (BPO); the solvent therein comprises a cosolvent for dissolving benzoyl peroxide and water for dissolving butanone peroxide.

[0011] Furthermore, the co-solvent comprises isopropanol and monoethanolamine; preferably, by mass, BPO:isopropanol=1:1-1:4, BPO:monoethanolamine=1:0.3-1:1.2.

[0012] Furthermore, the acid is added in the form of acid solution, and the mass concentration (w%) of the acid solution in the composite solution is 5%-25%. Preferably, the acid solution is selected from nitric acid solution with a concentration of 5%-25%, more preferably 20-25%.

[0013] Furthermore, the complexing agent is added in the form of a complexing agent solid, and the mass concentration (w%) of the silver complexing agent in the composite solution is 0.5-7.5%, preferably 2.5-5.0%; preferably, the complexing agent is ammonium nitrate.

[0014] The second aspect of the present invention provides a method for dissolving silver in waste photovoltaic cell assemblies, comprising the following steps:

[0015] 1) removing the aluminum frame of the waste battery assembly to obtain the battery assembly to be separated;

[0016] 2) Removing the TPT back plate, glass and EVA in the battery assembly to obtain a battery cell;

[0017] 3) placing the cell sheet in a composite solution for dissolving silver in waste photovoltaic cell assemblies, reacting in a sealed state, and separating to obtain a liquid phase containing silver ions.

[0018] Furthermore, in the step 3), the reaction is carried out under ultrasonic vibration, and the ultrasonic vibration conditions include: ultrasonic frequency of 28-40kHz, temperature of 65-90°C, ultrasonic time of 0.5-2.5h, and ultrasonic power of 30-50W / L.

[0019] Furthermore, in the step 3), the solid-liquid ratio (w:w) of the battery cell and the composite solution is 1:1-1:10.

[0020] Compared with the prior art, the present invention has the following advantages:

[0021] The present invention places the cell sheets in the waste photovoltaic cell assembly in a composite solution of dissolved silver, reacts in a sealed state, avoids the volatilization of volatile components such as nitrate and ammonium, and can separate the crystalline silicon sheet and the liquid phase containing silver ions. The composite solution of dissolved silver contains an acid, an oxidant for oxidizing the silver element to silver ions, and a complexing agent for complexing the silver ions; wherein, the elemental silver loses electrons to generate silver ions through the oxidation action of the oxidant, and the silver ions and the silver complexing agent generate silver ammonia complex ions through the complex reaction, that is, the present invention realizes the efficient leaching of low-grade silver in the crystalline silicon cell through the reaction of the combined oxidation, complexation and acid leaching system, and realizes the efficient leaching and separation of inert metal silver from the photovoltaic cell sheet, and obtains a complete crystalline silicon sheet at the same time. In addition, for the cell sheets obtained by the physical crushing or pulverization separation method, the present invention can realize the leaching and separation of silver through the above-mentioned chemical reaction with silver.

[0022] Other features and advantages of the present invention will be described in detail through the following detailed description. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 The flowchart of the method for dissolving silver in waste photovoltaic cell assemblies in Example 1 of the present invention is illustrated. DETAILED DESCRIPTION

[0024] The present application is further described below in conjunction with embodiments, but the present application is not limited to the listed embodiments, but also includes equivalent improvements and modifications of the technical solutions defined in the claims attached to the present application.

[0025] The endpoints and any values ​​of the ranges disclosed in this article are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of each range, the endpoint values ​​of each range and the individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed in this article.

[0026] Unless otherwise specified, the materials used in the embodiments of the present invention can be obtained from commercial channels.

[0027] The first aspect of the present invention provides a composite solution for dissolving silver in waste photovoltaic cell components, wherein the composite solution comprises an acid, an oxidant for oxidizing silver element into silver ions, and a complexing agent for complexing the silver ions.

[0028] In some examples, the oxidant is added in the form of an oxidant solution, and the mass concentration (w%) of the oxidant in the composite solution is 0.25%-5%, preferably 2.5-5%. Silver is a very inert metal, and the role of the oxidant is to stimulate the activity of silver. The content of silver in the battery cell is within a certain range (0.02%-0.1%). The inventors of this application found in their research that if the concentration of the oxidant in the composite solution is too low, it will not have an oxidizing effect; if the concentration of the oxidant in the composite solution is too high, the dissolution of silver is close to saturation, which will affect the stability of crystalline silicon.

[0029] In some examples, the oxidant is selected from one of H2O2, methyl ethyl peroxide, benzoyl peroxide, or a mixture thereof.

[0030] In some examples, the solvent in the oxidant solution is selected from one or more of water, isopropanol, and monoethanolamine.

[0031] In some examples, the oxidant solution is a mixture solution of butanone peroxide and benzoyl peroxide (BPO); the solvent includes a co-solvent for dissolving benzoyl peroxide and water for dissolving butanone peroxide.

[0032] In some examples, the co-solvent includes isopropanol and monoethanolamine; preferably, by mass, BPO:isopropanol=1:1-1:4, BPO:monoethanolamine=1:0.3-1:1.2.

[0033] In a preferred example, the oxidant is a mixture of H2O2, methyl ethyl peroxide, and benzoyl peroxide.

[0034] In some examples, the acid is added in the form of acid solution, and the mass concentration (w%) of the acid solution in the composite solution is 5%-25%. Preferably, the acid solution is selected from a nitric acid solution with a concentration of 5%-25%, and more preferably 20-25%. The acid solution provides a stable chemical field for the leaching of silver and the silver complex ions, and can also be used as a reagent for the dissolution reaction. If the acid concentration is too low, the reaction efficiency is low or even no reaction occurs. If the acid concentration is too high, waste is caused and the subsequent acid treatment material consumption increases.

[0035] In some examples, the complexing agent is added in the form of a complexing agent solid, and the complexing agent is ammonium nitrate, and the mass concentration (w%) of the complexing agent in the composite solution is 0.5-7.5%, preferably 2.5-5.0%. Ammonium nitrate is used as a complexing agent to form silver ammonia complex ions with silver ions, and its stability constant Wie10 7.23 When the concentration of the complexing agent is too low, the complex ion cannot be completely formed; when the concentration is too high, residual NH4 + The increase in content increases the ammonia nitrogen in the solution and makes wastewater treatment more difficult.

[0036] The second aspect of the present invention provides a method for dissolving silver in waste photovoltaic cell assemblies, comprising the following steps:

[0037] 1) removing the aluminum frame of the waste battery assembly to obtain the battery assembly to be separated;

[0038] 2) Removing the TPT back plate, glass and EVA in the battery assembly to obtain a battery cell;

[0039] 3) placing the cell sheet in a composite solution for dissolving silver in waste photovoltaic cell assemblies, reacting in a sealed state, and separating to obtain a liquid phase containing silver ions.

[0040] In some examples, in step 2), removing the TPT back plate in the battery assembly includes: placing the battery assembly to be separated in a composite solution I to obtain a battery assembly with the TPT back plate separated. The composite solution I includes: an acid, a composite oxidant, an oxygen free radical conductor, and an acid-resistant penetrant; the composite oxidant includes benzoyl peroxide, butanone peroxide, and a solvent for dissolving them;

[0041] Preferably, by mass, the ratio of battery component:composite solution I=1:1-1:5.

[0042] Preferably, in the composite solution I, by mass, acid: composite oxidant: oxygen free radical conductor: acid-resistant penetrant = 100: (5-35): (5-25): (0.2-0.8). The above ratio is the mass ratio between the solutions of the components.

[0043] Furthermore, in the step 2), removing the glass and EVA in the battery assembly comprises: placing the battery assembly separated from the TPT backplane in a composite solution II to obtain separated glass, battery cells and EVA. The composite solution II comprises: an alkali, a composite oxidant and an alkali-resistant penetrant, and the composite oxidant comprises benzoyl peroxide, butanone peroxide and a solvent for dissolving them.

[0044] Preferably, in terms of mass fraction, the battery component:composite solution II=1:1-1:3.

[0045] Preferably, in the composite solution II, alkali: composite oxidant: alkali-resistant penetrant = 100:

[0046] (1-5): (0.2-0.8). The above ratios are the mass ratios between the solutions of the components.

[0047] Preferably, the solvent of the composite oxidant comprises a co-solvent for dissolving benzoyl peroxide and water for dissolving methyl ethyl peroxide; the co-solvent comprises isopropanol and monoethanolamine.

[0048] Preferably, by mass, BPO:isopropanol=1:1-1:4, BPO:monoethanolamine=1:0.3-1:1.2.

[0049] In some exemplary composite solutions I and II, the acid is selected from a sulfuric acid solution, a hydrochloric acid solution or a mixture thereof with a concentration of 10% to 30%;

[0050] The oxygen free radical conductor is selected from a tetravalent titanium solution, a pentavalent vanadium solution or a mixture thereof, and the concentration is preferably 20-30%;

[0051] The acid-resistant penetrant is selected from one or more of OE-35 penetrant and JFC series penetrant;

[0052] The alkali is selected from a sodium hydroxide solution, a potassium hydroxide solution or a mixture thereof with a concentration of 10% to 30%;

[0053] The alkali-resistant penetrant is selected from one or more of the group consisting of rapid penetrant T, oep-98 penetrant, and oep-70 penetrant.

[0054] In some examples, in step 3), the reaction is carried out under ultrasonic vibration, and the ultrasonic vibration conditions include: ultrasonic frequency of 28-40kHz, temperature of 65-90°C, ultrasonic time of 0.5-2.5h, and ultrasonic power of 30-50W / L.

[0055] In some examples, in step 3), the liquid-to-solid ratio (w:w) of the composite solution and the battery cell is 1:1-10:1. The dissolution of silver is a solid-liquid reaction. When the liquid-to-solid mass ratio is too low, on the one hand, the solid cannot be completely immersed in the liquid phase, resulting in incomplete leaching of silver. On the other hand, the liquid-to-solid mass ratio is too low, which increases the viscosity of the slurry, is not conducive to mass transfer, and affects the reaction efficiency. When the liquid-to-solid mass ratio is too high, the leaching reaction of silver reaches the limit, which leads to waste of solution on the one hand, and makes the concentration of silver ions in the solution too low on the other hand, which increases the difficulty of subsequent silver enrichment and recovery.

[0056] In some examples, the reaction for dissolving silver in the present invention is as follows:

[0057] 2Ag + oxidant (H2O2) + 2NH4NO3 = Ag (NH3) (NO3) 2 + H2O

[0058] The present invention is described in detail below by way of examples:

[0059] Example 1

[0060] 1) Disassembly of aluminum frame: Use manual disassembly method to disassemble the aluminum frame around the component. Note that tempered glass is fragile, so use a cutting knife to cut slowly during disassembly.

[0061] 2) Remove the components with aluminum frames and cut the cells into small pieces of about 3cm*5cm by laser cutting. In order to avoid damage to the tempered glass during the cutting process, acid corrosive agents are added.

[0062] 3) Preparation of composite oxidant solution: weigh 25g of BPO, add 25g of isopropanol and 15g of monoethanolamine respectively, add 10g of water, seal, add a magnetic rotor, and stir electromagnetically until completely dissolved; after complete dissolution, add 25g of butanone peroxide and stir until dissolved.

[0063] 4) Weigh 30.6g of concentrated sulfuric acid into a beaker, add deionized water to 100g, stir until uniform to prepare a 30% sulfuric acid solution. Weigh 25g of titanium sulfate into a beaker, dissolve it with 75g of 5% sulfuric acid solution until uniform, and prepare a 25% oxygen free radical conductor solution. Take a cut battery component (weighing mass of 14.79g) and put it into a beaker, add 15g of 30% sulfuric acid solution, 5g of composite oxidant solution, 2.5g of oxygen free radical conductor solution, and 0.06g of penetrant OE-35, stir evenly, and seal.

[0064] 5) The beaker in step 4) was placed under ultrasonic vibration, with an ultrasonic frequency of 40 kHz, a power of 50 W / L, a temperature of 60° C., an ultrasonic time of 1 h, and 6 ultrasonic times. The organic matter separation efficiency was measured each time, with TPT back plate separation as the standard.

[0065] 6) Weigh 30g of sodium hydroxide into a beaker, add deionized water to 100g, stir until dissolved evenly, and prepare a 30% sodium hydroxide solution. Take out the sample separated from the back panel in step 5), place it in a beaker, add 15g of 30% alkaline solution, 5g of composite oxidant solution and 0.05g of OEP-98 penetrant, mix evenly, and seal;

[0066] 7) The beaker in step 6) is placed under ultrasonic vibration, with an ultrasonic frequency of 40 kHz, a power of 50 W / L, a temperature of room temperature, an ultrasonic time of 1 h, and 5 ultrasonic times, and the inorganic separation efficiency is tested each time, with the separation of glass, EVA and battery cells as the standard;

[0067] 8) Prepare a silver leaching composite solution: Mix and dissolve an oxidant, a complexing agent and an acid according to a certain concentration until they are uniform. The oxidant is a mixture of H2O2, butanone peroxide and benzoyl peroxide, and the mass concentration (w%) in the mixed solution is 5%; the complexing agent is ammonium nitrate, and the mass concentration (w%) in the mixed solution is 5.0%; the acid is nitric acid, and the mass concentration (w%) in the mixed solution is 20%.

[0068] 9) The battery cell obtained in step 7) and the composite solution obtained in step 8) are placed in a beaker at a solid-liquid ratio of 1:5, mixed evenly, sealed, and subjected to ultrasonic reaction at a certain temperature for a certain time. The mass of the battery cell is 1.5232g, the mass of the composite solution is 7.5g, the reaction temperature is 70°C, the reaction time is 1.5h, the ultrasonic frequency is 35kHz, and the power is 50W / L.

[0069] 10) Separation and cleaning: Filter the solution after the reaction in step 9) to obtain a liquid phase and a solid phase. Use dilute nitric acid to clean and filter the solid phase after the reaction. The concentration of the dilute nitric acid is 5%, and the mass of the cleaning solution is 2.5 g.

[0070] 11) The volume of the liquid phase obtained in step 10) is weighed, and a certain solution is taken for ICP test to test the silver concentration therein.

[0071] 12) Calculate the leaching rate of silver.

[0072]

[0073] η Ag is the leaching rate of silver, %

[0074] V is the volume of the leaching solution, ml

[0075] C Ag is the concentration of silver in the leaching solution, mg / l

[0076] m Ag is the mass of silver in the cell, mg, which is the cell mass multiplied by the silver content.

[0077] Example 2

[0078] This example is carried out in a similar manner to Example 1, except that step 8) uses 25% nitric acid solution.

[0079] Example 3

[0080] This example is carried out in a similar manner to Example 1, except that: in step 9), the composite solution is 5.0 g.

[0081] Example 4

[0082] This example is carried out in a similar manner to Example 1, except that: in step 9), the composite solution is 2.5 g.

[0083] Example 5

[0084] This example is carried out in a similar manner to Example 1, except that in step 8), hydrogen peroxide is used as the oxidant at a concentration of 5%.

[0085] Example 6

[0086] This example is carried out in a similar manner to Example 1, except that the concentration of the complexing agent used in step 8) is 2.5%.

[0087] Example 7

[0088] This example is carried out in a similar manner to Example 1, except that the solid-liquid ratio of the battery cell obtained in step 7) and the composite solution obtained in step 8) is 1:1, that is, the composite solution in step 9) is 1.5 g.

[0089] Example 8

[0090] This example is carried out in a similar manner to Example 1, except that in step 8), the mass concentration (w%) of the oxidant in the mixed solution is 2.5%.

[0091] Example 9

[0092] This example is carried out in a similar manner to Example 1, except that in step 8), the mass concentration (w%) of the acid solution in the mixed solution is 20%.

[0093] Comparative Example 1

[0094] The method is similar to that of Example 1, except that in step 8), no oxidant and silver complexing agent are added.

[0095] Comparative Example 2

[0096] The method is similar to that of Example 1, except that no oxidant is added in step 8).

[0097] Comparative Example 3

[0098] The method is similar to that of Example 1, except that step 8) uses hydrogen peroxide as an oxidation agent and does not add a silver complexing agent.

[0099] The Ag leaching rate of Examples 1-6 and Comparative Examples 1-3 was tested and studied. The unit is (%). The test results are shown in Table 1.

[0100] Table 1

[0101]

[0102] The results in Table 1 are analyzed as follows:

[0103] 1) By comparing the examples with comparative example 1, it can be seen that the silver leaching rate obtained by the method of the examples of the present application is above 84%; the silver leaching rate of direct acid leaching (without using an oxidant and a complexing agent) is zero under low acid concentration, indicating that low acid concentration alone does not have the ability to leach silver.

[0104] 2) By comparing the embodiment with comparative example 2, it can be seen that the leaching rate of silver obtained by the method of the embodiment of the present application is above 84%; the leaching rate of silver by direct complexation-acid leaching under low concentration acid is zero, indicating that the combined effect of low concentration acid and complexing agent does not have the ability to leach silver.

[0105] 3) By comparing the embodiment with comparative example 3, it can be seen that the silver leaching rate obtained by the method of the embodiment of the present application is above 84%; the silver leaching rate of single oxidation-acid leaching under low acid concentration is less than 25%, and the oxidation and dissolution capacity of a single oxidant is insufficient.

[0106] 4) By comparing Example 1 and Example 5, it can be seen that: Example 1 uses a composite oxidant (a mixture of H2O2, butanone peroxide, and benzoyl peroxide), and the silver leaching rate reaches 92.27%, while Example 5 uses a single oxidant, hydrogen peroxide, and the silver leaching rate is 84.73%, indicating that the synergistic oxidation effect of the composite oxidant is higher than that of the single oxidant, and the oxidative dissolution of silver is enhanced.

[0107] In summary, the present invention realizes the green and efficient leaching of inert silver in the battery through the synergistic effect of low-concentration acid, silver complexing agent and oxidant, thereby solving the problem that low-concentration acid does not react with inert metallic silver; the method of the present invention aims at the problems of low reaction efficiency, high concentration of nitric acid or hydrofluoric acid mixed acid and strong danger in conventional acid leaching method, and invents an oxidation-complexation synergistic reaction under a low-concentration acid method system, so as to achieve fast reaction rate, safety and environmental protection, and mainly solves the industry problems such as low reaction efficiency and large acid consumption in the process of recovering metallic silver in batteries.

[0108] Obviously, the above embodiments of the present invention are merely examples for clearly explaining the present invention, and are not intended to limit the implementation methods of the present invention. For those skilled in the art, other different forms of changes or modifications can be made based on the above description. It is impossible to list all implementation methods here. All obvious changes or modifications derived from the technical solution of the present invention are within the spirit scope of the present invention.

Claims

1. A composite solution for dissolving silver in waste photovoltaic cell components, characterized in that: The composite solution comprises an acid, an oxidant for oxidizing silver element into silver ions, and a complexing agent for complexing the silver ions.

2. The composite solution according to claim 1, characterized in that: The oxidant is added in the form of an oxidant solution, and the mass concentration of the oxidant in the composite solution is 0.25%-5%; preferably, the oxidant is selected from one of H2O2, butanone peroxide, benzoyl peroxide, or a mixture thereof.

3. The composite solution according to claim 2, characterized in that: The solvent in the oxidant solution is selected from one or more of water, isopropanol and monoethanolamine.

4. The composite solution according to any one of claims 1 to 3, characterized in that: The oxidant solution is a mixture solution of butanone peroxide and benzoyl peroxide; the solvent therein comprises a cosolvent for dissolving benzoyl peroxide and water for dissolving butanone peroxide.

5. The composite solution according to claim 4, characterized in that: The co-solvent comprises isopropanol and monoethanolamine; preferably, by mass, benzoyl peroxide:isopropanol=1:1-1:4, benzoyl peroxide:monoethanolamine=1:0.3-1:1.

2.

6. The composite solution according to claim 1, characterized in that: The acid is added in the form of acid solution, and the mass concentration of the acid solution in the composite solution is 5%-25%; preferably, the acid solution is selected from a nitric acid solution with a concentration of 5%-25%.

7. The composite solution according to claim 1, characterized in that: The complexing agent is added in the form of complexing agent solid, and the mass concentration of the complexing agent in the composite solution is 0.5-7.5%. Preferably, the complexing agent is ammonium nitrate.

8. A method for dissolving silver in waste photovoltaic cell components, characterized in that: The steps include: 1) removing the aluminum frame of the waste battery assembly to obtain the battery assembly to be separated; 2) Removing the TPT back plate, glass and EVA in the battery assembly to obtain a battery cell; 3) placing the cell sheet in the composite solution for dissolving silver in waste photovoltaic cell assemblies according to any one of claims 1 to 7, reacting in a sealed state, and separating to obtain a liquid phase containing silver ions.

9. The method for dissolving silver according to claim 8, characterized in that: In the step 3), the reaction is carried out under ultrasonic vibration, and the ultrasonic vibration conditions include: ultrasonic frequency of 28-40kHz, temperature of 65-90°C, ultrasonic time of 0.5-2.5h, and ultrasonic power of 30-50W / L.

10. The method for dissolving silver according to claim 8, characterized in that: In the step 3), the solid-liquid mass ratio of the battery cell to the composite solution is 1:1-1:10.

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