A method for producing silver powder by using photovoltaic panel cell pieces

Abstract

The application relates to the technical field of silver powder preparation, and discloses a method for producing silver powder by using photovoltaic panel battery pieces, which comprises the following steps: S1, after waste photovoltaic battery pieces and acid liquor are initially mixed, a leaching agent is added for secondary mixing, and filtration is carried out to obtain a silver-containing liquid; S2, sodium chloride is added into the silver-containing liquid to obtain a precipitate; and S3, the precipitate is subjected to reduction treatment to obtain silver powder; and the components of the leaching agent include 8-hydroxyquinoline and / or pyridine-2,6-dicarboxylic acid. Through the technical scheme, the problem of low silver powder yield in the production of silver powder by using photovoltaic battery pieces in the related art is solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of silver powder preparation, in particular, to a method for producing silver powder by using photovoltaic panel cell. BACKGROUND

[0002] In the production process of photovoltaic cells, silver becomes the key material for preparing electrodes due to its excellent electrical conductivity and thermal conductivity. However, silver is a scarce noble metal resource with limited reserves and extremely uneven distribution. This makes the market price of silver fluctuate frequently, seriously affecting the production cost and sustainable development of the photovoltaic industry. Therefore, efficient recovery of silver powder from waste photovoltaic cells can not only alleviate the pressure of silver resource shortage and reduce the dependence of the photovoltaic industry on primary silver mines, but also reduce the potential harm of waste to the environment, which has significant economic and environmental benefits.

[0003] Currently, the methods for recovering silver powder from photovoltaic cells mainly include chemical leaching, pyrometallurgical method and mechanical stripping method. However, these methods generally have the problem of low silver powder yield in practical application. Chemical leaching method dissolves silver in the cell by using chemical reagents, and then recovers silver powder through reduction and other steps. Pyrometallurgical method is to melt the waste cell at high temperature to separate silver from other substances. Mechanical stripping method tries to directly separate silver electrode from the cell by physical means.

[0004] The above-mentioned methods for recovering silver powder from photovoltaic cells all have the problem of low recovery yield of silver powder. Therefore, it is necessary to improve the yield of silver powder to promote the sustainable development of the photovoltaic industry. SUMMARY

[0005] The present application provides a method for producing silver powder by using photovoltaic panel cell, which solves the problem of low silver powder yield in the related art when producing silver powder from photovoltaic cells.

[0006] The technical scheme of the present application is as follows:

[0007] The present application provides a method for producing silver powder by using photovoltaic panel cell, which includes the following steps:

[0008] S1, after the waste photovoltaic cell and the acid solution are initially mixed, the leaching agent is added for the second mixing, and the silver-containing liquid is obtained by filtration;

[0009] S2, sodium chloride is added to the silver-containing liquid to obtain a precipitate;

[0010] S3, the precipitate is subjected to reduction treatment to obtain silver powder;

[0011] The components of the leaching agent include 8-hydroxyquinoline and / or pyridine-2,6-dicarboxylic acid.

[0012] As a further technical solution, when the components of the leaching agent are 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid, the mass ratio of the 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid is 1:4~8.

[0013] In the present application, after the initial mixing of the waste photovoltaic cell and the acid solution to open the cell structure, the second mixing of the leaching agent composed of 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid is added, and the two will have a synergistic effect, greatly improving the leaching rate of silver. Compared with a single leaching agent, the leaching agent composed of 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid can further improve the yield of silver powder from photovoltaic cell production.

[0014] As a further technical solution, the concentration of the acid solution is 45wt%~55wt%, for example, it can be 45wt%, 47wt%, 49wt%, 50wt%, 52wt%, 54wt%, 55wt%, preferably 45wt%, 50wt%, 55wt%, more preferably 50wt%;

[0015] The mass-volume ratio of the waste photovoltaic cell and the acid solution is 1g:50~80mL, for example, it can be 1g:50mL, 1g:55mL, 1g:60mL, 1g:65mL, 1g:70mL, 1g:80mL, preferably 1g:60mL.

[0016] As a further technical solution, the mass of the leaching agent is 5%~10% of the mass of the acid solution, for example, it can be 5%, 6%, 7%, 8%, 9%, 10%.

[0017] As a further technical solution, the acid solution includes one or more of hydrochloric acid solution, nitric acid solution, and sulfuric acid solution.

[0018] As a further technical solution, the mass ratio of the sodium chloride to the silver-containing liquid is 0.4~0.8:1.

[0019] As a further technical solution, the temperature of the initial mixing is 30~40℃, and the time is 30~40min;

[0020] The temperature of the second mixing is 55~65℃, and the time is 90~110min.

[0021] The temperature of the second mixing is 55~65℃, and the time is 90~110min, which can not only accelerate the leaching of the leaching agent to promote silver ions, but also avoid other side reactions caused by high temperature. At the same time, under the reaction time of 90~110min, it can more efficiently ensure the sufficient leaching of silver ions.

[0022] As a further technical solution, the reduction treatment is performed by using iron powder.

[0023] As a further technical solution, the reduction treatment is followed by a purification treatment.

[0024] The purification treatment includes washing and drying treatment.

[0025] The washing is first performed by using water, and then by using a mixed solution of isopropyl alcohol and decanone.

[0026] As a further technical solution, the mass ratio of isopropyl alcohol to decanone is 4-8:1.

[0027] In the reduction treatment process of producing silver powder from photovoltaic cell pieces, the purification treatment greatly improves the quality of silver powder. The silver powder is first washed with water to remove most of the water-soluble impurities, and then further washed with a mixed solution of isopropyl alcohol and decanone. Isopropyl alcohol has strong solubility, and decanone can improve the surface tension of the mixed solution. The two work together to effectively remove the organic impurities and other metal ions remaining on the surface of the silver powder, and can obtain silver powder with less impurities and high purity, which is beneficial to meet the quality requirements of silver powder in high-end fields such as electronics, chemical industry, and optics.

[0028] The working principle and beneficial effects of the present application are as follows:

[0029] In the present application, the waste photovoltaic cell pieces are first mixed with acid solution to preliminarily open the structure of the cell pieces, and then a leaching agent containing 8-hydroxyquinoline and / or pyridine-2,6-dicarboxylic acid is added for secondary mixing. The leaching agent can improve the leaching rate of silver, and the addition of sodium chloride in the silver-containing solution can rapidly react with silver ions to form silver chloride precipitate, and the reaction process is easy to control. After a series of fine treatments such as leaching, precipitation, and reduction, the interference of other impurities in the cell pieces is effectively reduced, the yield of silver powder is improved, and the further reuse of silver powder is promoted. DETAILED DESCRIPTION

[0030] The technical solutions in the embodiments of the present application will be described clearly and completely in combination with the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all other embodiments obtained by those skilled in the art without creative labor are involved in the scope of protection of the present application.

[0031] Embodiment 1

[0032] The method for producing silver powder from photovoltaic panel cell pieces includes the following steps:

[0033] S1, the waste photovoltaic cell piece and the nitric acid solution with the concentration of 45wt% are mixed at 30°C for 40 min, the leaching agent (the mass of the leaching agent is 5% of the mass of the acid solution) is added and mixed at 55°C for 110 min, filtration is carried out, and the silver-containing liquid is obtained; the component of the leaching agent is 8-hydroxyquinoline;

[0034] S2, sodium chloride is added in the silver-containing liquid (the mass ratio of sodium chloride to the silver-containing liquid is 0.4:1), and the precipitate is obtained;

[0035] S3, the precipitate is treated by reduction with iron powder, washed with water, and dried, and the silver powder is obtained (the yield of the silver powder is 92.1%).

[0036] Example 2

[0037] The method for producing silver powder by using photovoltaic panel cell pieces comprises the following steps:

[0038] S1, the waste photovoltaic cell piece and the nitric acid solution with the concentration of 55wt% are mixed at 40°C for 30 min, the leaching agent (the mass of the leaching agent is 10% of the mass of the acid solution) is added and mixed at 65°C for 90 min, filtration is carried out, and the silver-containing liquid is obtained; the component of the leaching agent is pyridine-2,6-dicarboxylic acid;

[0039] S2, sodium chloride is added in the silver-containing liquid (the mass ratio of sodium chloride to the silver-containing liquid is 0.8:1), and the precipitate is obtained;

[0040] S3, the precipitate is treated by reduction with iron powder, washed with water, and dried, and the silver powder is obtained (the yield of the silver powder is 90.4%).

[0041] Example 3

[0042] The method for producing silver powder by using photovoltaic panel cell pieces comprises the following steps:

[0043] S1, the waste photovoltaic cell piece and the nitric acid solution with the concentration of 50wt% are mixed at 35°C for 35 min, the leaching agent (the mass of the leaching agent is 8% of the mass of the acid solution) is added and mixed at 60°C for 100 min, filtration is carried out, and the silver-containing liquid is obtained; the component of the leaching agent is 8-hydroxyquinoline;

[0044] S2, sodium chloride is added in the silver-containing liquid (the mass ratio of sodium chloride to the silver-containing liquid is 0.6:1), and the precipitate is obtained;

[0045] S3, the precipitate is treated by reduction with iron powder, washed with water, and dried, and the silver powder is obtained (the yield of the silver powder is 92.8%).

[0046] Example 4

[0047] The difference between this example and Example 3 is that the component of the leaching agent is pyridine-2,6-dicarboxylic acid;

[0048] The yield of the silver powder finally prepared is 91.9%.

[0049] Example 5

[0050] The difference between this example and Example 3 is that the component of the leaching agent is 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid at a mass ratio of 1:4;

[0051] The yield of the silver powder finally prepared is 94.0%.

[0052] Example 6

[0053] The difference between this example and Example 3 is that the component of the leaching agent is 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid at a mass ratio of 1:8;

[0054] The yield of the silver powder finally prepared is 93.6%, the content of silver element in the silver powder is 99.99%, the content of Cu element is 0.0018%, and the content of Fe element is 0.0014%.

[0055] Example 7

[0056] The method for producing silver powder by using photovoltaic panel cell pieces comprises the following steps:

[0057] S1, mixing waste photovoltaic cell pieces and a nitric acid solution with a concentration of 50wt% (the mass-volume ratio of the waste photovoltaic cell pieces and the nitric acid solution is 1g:60mL) at 35°C for 35min, adding a leaching agent (the mass of the leaching agent is 8% of the mass of the acid solution) and mixing at 60°C for 100min, filtering to obtain a silver-containing liquid; the component of the leaching agent is 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid at a mass ratio of 1:8;

[0058] S2, adding sodium chloride (the mass ratio of sodium chloride and the silver-containing liquid is 0.6:1) to the silver-containing liquid to obtain a precipitate;

[0059] S3, reducing the precipitate by using iron powder, washing by using water first, then washing by using isopropyl alcohol, drying to obtain silver powder (the yield of the silver powder is 93.1%, the content of silver element in the silver powder is 99.99%, the content of Cu element is 0.0013%, and the content of Fe element is 0.0010%).

[0060] Example 8

[0061] The method for producing silver powder by using photovoltaic panel cell pieces comprises the following steps:

[0062] S1, the waste photovoltaic cell and the nitric acid solution with a concentration of 50wt% (the mass-volume ratio of the waste photovoltaic cell and the nitric acid solution is 1g:60mL) are mixed at 35°C for 35min, a leaching agent (the mass of the leaching agent is 8% of the mass of the acid solution) is added and mixed at 60°C for 100min, and then filtered to obtain a silver-containing liquid; the components of the leaching agent are 8-hydroxyquinoline and pyridine-2, 6-dicarboxylic acid with a mass ratio of 1:8;

[0063] S2, sodium chloride is added to the silver-containing liquid (the mass ratio of sodium chloride to the silver-containing liquid is 0.6:1) to obtain a precipitate;

[0064] S3, the precipitate is reduced by iron powder, washed with water first, then washed with decanone, and dried to obtain silver powder (the yield of silver powder is 93.1%, the content of silver element in the silver powder is 99.99%, the content of Cu element is 0.0014%, and the content of Fe element is 0.0012%).

[0065] Example 9

[0066] The method for producing silver powder by using photovoltaic panel cell includes the following steps:

[0067] S1, the waste photovoltaic cell and the nitric acid solution with a concentration of 50wt% (the mass-volume ratio of the waste photovoltaic cell and the nitric acid solution is 1g:60mL) are mixed at 35°C for 35min, a leaching agent (the mass of the leaching agent is 8% of the mass of the acid solution) is added and mixed at 60°C for 100min, and then filtered to obtain a silver-containing liquid; the components of the leaching agent are 8-hydroxyquinoline and pyridine-2, 6-dicarboxylic acid with a mass ratio of 1:8;

[0068] S2, sodium chloride is added to the silver-containing liquid (the mass ratio of sodium chloride to the silver-containing liquid is 0.6:1) to obtain a precipitate;

[0069] S3, the precipitate is reduced by iron powder, washed with water first, then washed with a mixed solution of isopropyl alcohol and decanone with a mass ratio of 4:1, and dried to obtain silver powder (the yield of silver powder is 93.0%, the content of silver element in the silver powder is 99.99%, the content of Cu element is 0.0009%, and the content of Fe element is 0.0007%).

[0070] Example 10

[0071] The difference between this embodiment and example 9 is that in step S3, the precipitate is reduced by iron powder, washed with water first, then washed with a mixed solution of isopropyl alcohol and decanone with a mass ratio of 8:1, and dried to obtain silver powder (the yield of silver powder is 93.6%, the content of silver element in the silver powder is 99.99%, the content of Cu element is 0.0010%, and the content of Fe element is 0.0004%).

[0072] Comparative Example 1

[0073] The method for producing silver powder by using photovoltaic panel cell includes the following steps:

[0074] S1, mixing waste photovoltaic cell and nitric acid solution with a concentration of 50wt% (the mass-volume ratio of waste photovoltaic cell and nitric acid solution is 1g:60mL) at 35℃ for 135min, filtering to obtain a silver-containing liquid; the components of the leaching agent are 8-hydroxyquinoline;

[0075] S2, adding sodium chloride (the mass ratio of sodium chloride and silver-containing liquid is 0.6:1) to the silver-containing liquid to obtain a precipitate;

[0076] S3, reducing the precipitate by using iron powder, washing with water, and drying to obtain silver powder (the yield of silver powder is 84.3%).

[0077] Comparing Example 3~4 and Comparative Example 1, it is found that the yield of silver powder prepared by Example 3~4 is higher, which indicates that when recovering silver powder from waste photovoltaic cell, adding 8-hydroxyquinoline and pyridine-2,6-dicarboxylic acid as leaching agent can improve the yield of silver powder.

[0078] Comparing Example 6~10, it is found that the yield of silver powder prepared by Example 9~10 is higher, which indicates that when recovering silver powder from waste photovoltaic cell, first washing with water and then washing with a mixture of isopropyl alcohol and decanone can reduce the content of other elements in silver powder and improve the purity of silver powder.

[0079] The above is only a preferred embodiment of the present application, and is not intended to limit the present application, any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included in the protection scope of the present application.

Claims

1. A method for producing silver powder using photovoltaic panel cells, characterized by, The method comprises the following steps: S1, after the waste photovoltaic cell and the acid solution are initially mixed, an immersion agent is added for secondary mixing, and filtration is performed to obtain a silver-containing liquid; S2, sodium chloride is added to the silver-containing liquid to obtain a precipitate; S3, the precipitate is subjected to reduction treatment to obtain silver powder; The components of the immersion agent are 8-hydroxyquinoline and pyridine-2, 6-dicarboxylic acid, and the mass ratio of the 8-hydroxyquinoline to the pyridine-2, 6-dicarboxylic acid is 1:4-8; The reduction treatment is further subjected to a purification treatment; The purification treatment comprises washing and drying treatment; During the washing, water is used for washing first, and then a mixed solution of isopropyl alcohol and decanone is used for washing.

2. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, characterized by, The concentration of the acid solution is 45wt%-55wt%; The mass-volume ratio of the waste photovoltaic cell to the acid solution is 1g:50-80mL.

3. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, characterized by, The mass of the immersion agent is 5%-10% of the mass of the acid solution.

4. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, characterized by, The acid solution comprises one or more of a hydrochloric acid solution, a nitric acid solution, and a sulfuric acid solution.

5. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, wherein The mass ratio of the sodium chloride to the silver-containing liquid is 0.4-0.8:

1.

6. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, wherein The temperature of the initial mixing is 30-40℃, and the time is 30-40min; The temperature of the secondary mixing is 55-65℃, and the time is 90-110min.

7. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, wherein Iron powder is used for the reduction treatment during the reduction.

8. The method for producing silver powder using photovoltaic panel cell pieces according to claim 1, wherein The mass ratio of the isopropyl alcohol to the decanone is 4-8:1.