Method for recycling waste crystalline silicon cells and SiC / AlN composite powder and preparation method thereof

Abstract

The present application relates to waste silicon crystal battery recycling technical field, specifically, it relates to the recycling method of waste silicon crystal battery and SiC\AlN composite powder and its preparation method. The recycling method of waste silicon crystal battery comprises: the waste silicon crystal battery piece with EVA glue is subjected to pre-carbonization treatment after peeling, then, crushing and screening, wherein, the temperature of pre-carbonization treatment is 280-320 DEG C, the vacuum degree is 0.06-0.08 MPa, and the time is 6-10 hours;Screening includes that the crushed material is subjected to primary screening through 90-110 mesh, and then the undersize material is subjected to depth screening through 400-425 mesh. The recycling method does not use organic solvent and chemical reagent, does not need to separate single component, and can be used for preparing SiC\AlN composite powder.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of waste silicon battery recycling, in particular to a waste silicon battery recycling method and SiC\AlN composite powder and a preparation method thereof. BACKGROUND

[0002] The first generation of solar photovoltaic cell panels has entered a large-scale retirement period. The silicon wafer in the crystalline silicon cell of the photovoltaic solar cell panel has a complex preparation process and high cost. Therefore, it is of great significance to recycle and reuse the silicon in the crystalline silicon cell. For example, aluminum is used as a negative electrode material in the crystalline silicon solar cell, and the content of aluminum is high. Therefore, the recycling and reuse of aluminum is particularly important. The existing waste crystalline silicon battery recycling methods mainly include the following two methods: (1) soaking the photovoltaic module in an organic solvent to recover the components of the photovoltaic module through the swelling effect of the organic solvent on EVA, and then heating or using a chemical reaction method to recover the single components in the module. (2) The mechanical rotating impact mechanism mechanically crushes the module, and then separates the fragments of the components of the photovoltaic module for recycling. The above two recycling methods have the following problems: the introduction of organic solvents or chemical reagents will cause environmental pollution problems in the later large-scale recycling; the mechanical crushing and sorting method mixes the components, which is difficult to separate in large quantities and effectively, and causes energy consumption and high recycling cost in the separation process.

[0003] In view of this, the present application is proposed. SUMMARY

[0004] The present application provides a waste crystalline silicon battery recycling method and SiC\AlN composite powder and a preparation method thereof. The waste crystalline silicon battery recycling method provided by the present application does not use organic solvents and chemical reagents, does not separate single components, and can be used to prepare SiC\AlN composite powder.

[0005] The present application is implemented as follows:

[0006] In a first aspect, the present application provides a waste crystalline silicon battery recycling method, comprising: pre-carbonizing the waste crystalline silicon cell piece with EVA glue after peeling, and then crushing and screening.

[0007] The pre-carbonization temperature is 280-320℃, the vacuum degree is 0.06-0.08MPa, and the time is 6-10 hours.

[0008] The screening includes initially screening the crushed material through 90-110 meshes, and then deeply screening the undersize material through 400-425 meshes.

[0009] In an optional embodiment, the crushing comprises cutting the pre-carbonization treated waste crystalline silicon battery piece into fragments, and then performing ball milling or deep crushing.

[0010] In an optional embodiment, the powdering and sieving are not performed on the 90-100 mesh and 440-425 mesh oversize.

[0011] In a second aspect, the present application provides a preparation method of SiC\AlN composite powder, comprising the recycling method of waste crystalline silicon battery piece according to any one of the preceding embodiments.

[0012] In an optional embodiment, the sintering is performed after mixing the 400-425 mesh undersize with a graphite-like substance.

[0013] In an optional embodiment, the mass ratio of the 400-425 mesh undersize to the graphite-like substance is 2.3-2.4:1.

[0014] In an optional embodiment, the sintering process comprises: holding at 450-500℃ for 15-25 minutes, then holding at 1100-1150℃ for 25-35 minutes, then holding at 1250-1350℃ for 100-130 minutes, and then holding at 1450-1500℃ for 100-130 minutes.

[0015] In an optional embodiment, the sintering process comprises: heating at a rate of 3-4℃ / min to 450-500℃ and holding for 15-25 minutes, then heating at a rate of 1.5-2℃ / min to 1100-1150℃ and holding for 25-35 minutes, then heating at a rate of 0.5-1℃ / min to 1250-1350℃ and holding for 100-130 minutes, and then heating at a rate of 1-2℃ / min to 1450-1500℃ and holding for 100-130 minutes.

[0016] In an optional embodiment, the sintering is performed at a rate of 3-4℃ / min to 450-500℃ and holding for 15-25 minutes, then heating at a rate of 1.5-2℃ / min to 1100-1150℃ and holding for 25-35 minutes, then heating at a rate of 0.5-1℃ / min to 1250-1350℃ and holding for 100-130 minutes, and then heating at a rate of 1-2℃ / min to 1450-1500℃ and holding for 100-130 minutes.

[0017] In an optional embodiment, the sintering is performed at a rate of 3-4℃ / min to 450-500℃ and holding for 15-25 minutes, then heating at a rate of 1.5-2℃ / min to 1100-1150℃ and holding for 25-35 minutes, then heating at a rate of 0.5-1℃ / min to 1250-1350℃ and holding for 100-130 minutes, and then heating at a rate of 1-2℃ / min to 1450-1500℃ and holding for 100-130 minutes.

[0018] The present application has the following advantages: the recycling method provided by the embodiments of the present application does not need to separate the components in the waste silicon battery piece, can realize complete recycling of the silicon battery piece, complete recycling of the aluminum electrode, and preparation of SiC\AlN composite material using Si and Al in the waste silicon battery piece. No organic solvent or chemical reagent is used in the recycling process to cause environmental pollution, and the recycling and reuse process is simple and easy to implement. BRIEF DESCRIPTION OF DRAWINGS

[0019] In order to more clearly illustrate the technical solutions of the embodiments of the present application, the drawings required to be used in the embodiments will be briefly introduced as follows. It should be understood that the following drawings only show some of the embodiments of the present application, and therefore should not be regarded as a limitation on the scope. For those of ordinary skill in the art, other related drawings can also be obtained without creative labor on the basis of these drawings.

[0020] Figure 1 Phase diagram of the product provided for Example 1 of the present application;

[0021] Figure 2 Phase diagram of the product provided for Comparative Example 3 of the present application;

[0022] Figure 3 Phase diagram of the product provided for Comparative Example 4 of the present application;

[0023] Figure 4 Phase diagram of the pre-carbonized material provided for Comparative Example 1 of the present application;

[0024] Figure 5 Phase diagram of the pre-carbonized material provided for Comparative Example 2 of the present application. DETAILED DESCRIPTION

[0025] In order to make the purpose, technical solutions and advantages of the embodiments of the present application more clear, the technical solutions in the embodiments of the present application will be clearly and completely described as follows. If the specific conditions are not specified in the embodiments, the conventional conditions or the conditions recommended by the manufacturer will be used. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased on the market.

[0026] The present application provides a recycling method of waste crystalline silicon cells, comprising:

[0027] The waste crystalline silicon cell pieces with EVA glue adhered after peeling are subjected to pre-carbonization treatment. The preparation of the waste crystalline silicon cell pieces with EVA glue adhered after peeling is known, and the embodiments of the present application will not be described in detail, for example, please refer to CN115254911 A.

[0028] Specifically, the conditions of the pre-carbonization treatment include: a temperature of 280-320℃, a vacuum degree of 0.06-0.08 MPa, and a time of 6-10 hours. For example, the temperature is any value between 280-320℃ or a range value between any two values, such as 280℃, 290℃, 300℃, 310℃, and 320℃. The vacuum degree is any value between 0.06-0.08 MPa or a range value between any two values, such as 0.06 MPa, 0.07 MPa, and 0.08 MPa. The time is any value between 6-10 hours or a range value between any two values, such as 6 hours, 7 hours, 8 hours, 9 hours, and 10 hours.

[0029] The pre-carbonization treatment is adopted in the embodiment of the present application, so that the EVA glue is preliminarily pyrolyzed and hardened, which can facilitate subsequent crushing and screening, and can facilitate subsequent mixing with graphite substances to form SiC\AlN composite powder. In particular, a small amount of SiC is generated in this step, so as to achieve partial recovery of the EVA glue. At the same time, Al of the crystalline silicon battery negative electrode material can generate Al2O3 in this process, which provides raw materials for preparing AlN.

[0030] If the conditions of the pre-carbonization treatment are changed, especially the temperature, the waste crystalline silicon battery sheet can not be fully crushed, and then can not be uniformly mixed with graphite substances, and then can not form SiC\AlN composite powder.

[0031] And the color of the EVA after the pre-carbonization treatment is brown, which is hardened, but still adheres to the silicon battery sheet and does not fall off.

[0032] Then the waste crystalline silicon battery sheet after the pre-carbonization treatment is crushed and screened. Specifically, the crushing process is: the waste crystalline silicon battery sheet after the pre-carbonization treatment is cut into pieces, and then ball milling or deep crushing is performed. For example, the ball milling process is: under the rotation speed of 180 r / min, forward transmission for 30 minutes, stop for 5 minutes, reverse transmission for 30 minutes, and the cycle is repeated for 3 times. The deep crushing is: crushing in the crusher for 2 minutes, and then stopping in turn, and the cycle is repeated for 3 times.

[0033] It should be noted that the crushing can adopt the existing crushing technology, as long as the crushed material can meet the subsequent screening. The embodiment of the present application illustrates that the waste crystalline silicon battery sheet is first cut into pieces (equivalent to primary crushing), and then ground or deeply crushed. It is only an example of better crushing effect, and is not limited to this crushing method.

[0034] The screening includes primary screening of the crushed material through 90-110 meshes, and then deeply screening the undersize material through 400-425 meshes. The undersize material through 400-425 meshes is the material recovered by the embodiment of the present application. The oversize material through 90-100 meshes and 440-425 meshes is recycled for the above crushing and screening.

[0035] In summary, the recycling process of the embodiment of the present application does not use organic solvents or chemical reagents to cause environmental pollution, and the recycling and reuse process is simple and easy to implement.

[0036] In a second aspect, the present application provides a preparation method of SiC\AlN composite powder, which comprises the recycling method of the waste crystalline silicon solar cell according to any one of the preceding embodiments, and specifically:

[0037] The above-mentioned undersize through a 400-425 mesh sieve is mixed with a graphite substance and then sintered. The mass ratio of the undersize through a 400-425 mesh sieve to the graphite substance is 2.3-2.4:1. For example, it is any value between 2.3:1, 2.31:1, 2.32:1, 2.33:1, 2.34:1, 2.35:1, 2.36:1, 2.37:1, 2.38:1, 2.39:1 and 2.4:1, or a range value between any two values. The graphite substance can be selected from graphite powder.

[0038] The sintering process comprises: holding at 450-500℃ for 15-25 minutes, then holding at 1100-1150℃ for 25-35 minutes, then holding at 1250-1350℃ for 100-130 minutes, and then holding at 1450-1500℃ for 100-130 minutes. Specifically, the temperature is raised to 450-500℃ at a rate of 3-4℃ / min, held for 15-25 minutes, then raised to 1100-1150℃ at a rate of 1.5-2℃ / min, held for 25-35 minutes, then raised to 1250-1350℃ at a rate of 0.5-1℃ / min, held for 100-130 minutes, and then raised to 1450-1500℃ at a rate of 1-2℃ / min, held for 100-130 minutes. After sintering, the furnace is naturally cooled.

[0039] In summary, according to the content of each element in the waste crystalline silicon solar cell and the chemical reactions that occur during sintering, the mass ratio of the waste crystalline silicon solar cell to graphite for preparing SiC is used in the embodiment of the present application. Al in the waste silicon solar cell and the antireflection film SiN of the silicon solar cell are used to prepare AlN through the chemical reaction during high-temperature sintering, i.e., the SiC\AlN composite powder is prepared from the waste crystalline silicon solar cell.

[0040] The features and performance of the present application are further described in detail below in combination with embodiments.

[0041] Embodiment 1

[0042] The embodiment provides a preparation method of SiC\AlN composite powder, which comprises:

[0043] a, EVA glue pre-carbonization process: the waste crystalline silicon battery pieces with EVA glue adhered after peeling (see CN115254911 A for preparation) were dried in a vacuum drying box. The vacuum degree of drying was 0.08 Mpa, the drying temperature was 300 DEG C, and the drying time was 10 hours. After drying, the EVA color was brownish, hardened, but still adhered to the silicon battery pieces.

[0044] b, the pre-carbonized silicon battery pieces were cut into small square pieces of about 1 cm*1 cm with scissors, and the small square pieces were put into a ball mill for ball milling and crushing. The ball milling process was 30 minutes of forward rotation at 180 r / min, 5 minutes of stop, and then 30 minutes of reverse rotation, and the cycle was repeated for 3 times.

[0045] The crushed sample was a mixture of powder and uncrushed waste silicon battery pieces.

[0046] c, the crushed powder needs to be sieved through a 100 mesh sieve for primary screening and then sieved through a 400 mesh sieve. The sieved powder can be used for preparing SiC\AlN composite powder.

[0047] In the above step c, after sieving, the remaining silicon battery piece fragments on the sieve can be continuously crushed and repeated step c.

[0048] d, the sieved material after 400 mesh sieving and graphite were mixed uniformly according to the mass ratio of 2.33:1, and then sintered. The sintering process was carried out in a high temperature tube furnace with argon protection.

[0049] Powder laying process: graphite paper was laid on the bottom and side of the porcelain boat to prevent the formation of solidified material attached to the porcelain boat during sintering, and to prevent other impurities in the porcelain boat from entering the mixed powder during the sintering process. The mixed powder was laid flat on the graphite paper with a thickness of about 1 mm, and the upper cover of the porcelain boat was covered to prevent the mixed powder from entering the corundum tube with argon during sintering. The sintering was carried out in a tube furnace.

[0050] Sintering process: the initial temperature was 50 DEG C, the temperature was raised to 450 DEG C at a rate of 4 DEG C / min, the temperature was kept for 20 min, the temperature was raised to 1100 DEG C at a rate of 2 DEG C / min, the temperature was kept for 30 min, the temperature was raised to 1350 DEG C at a rate of 1 DEG C / min, the temperature was kept for 120 min, and then the temperature was raised to 1500 DEG C. The sintered sample was taken out after the temperature was lowered to the natural temperature at a rate of 2 DEG C / min.

[0051] Characterization

[0052] The sintered powder prepared in Example 1 was subjected to XRD detection, and the results are shown in Figure 1 , according to Figure 1 , it can be seen that the sieved material after 400 mesh sieving and graphite react completely, there is no excess Si and excess graphite, and the product phase test shows SiC and AlN.

[0053] Example 2

[0054] The present example provides a method for preparing SiC\AlN composite powder, which is basically identical to that of Example 1, except that the undersize after passing through a 400-mesh sieve and graphite are in a mass ratio of 2.4:1.

[0055] Example 3

[0056] The present example provides a method for preparing SiC\AlN composite powder, which is basically identical to that of Example 1, except that the undersize after passing through a 400-mesh sieve and graphite are in a mass ratio of 2.3:1.

[0057] Example 4

[0058] The present example provides a method for preparing SiC\AlN composite powder, which is basically identical to that of Example 1, except that the undersize after passing through a 400-mesh sieve and graphite are in a mass ratio of 2.32:1.

[0059] Example 5

[0060] The present example provides a method for preparing SiC\AlN composite powder, which is basically identical to that of Example 1, except that the conditions for the pre-carbonization process are: vacuum degree of 0.07 MPa, temperature of 280℃, and time of 8 hours.

[0061] Example 6

[0062] The present example provides a method for preparing SiC\AlN composite powder, which is basically identical to that of Example 1, except that the conditions for the pre-carbonization process are: vacuum degree of 0.06 MPa, temperature of 320℃, and time of 6 hours.

[0063] Comparative Example 1

[0064] The present comparative example provides a method for recycling waste crystalline silicon cells, which is basically identical to that of Example 1, except that the conditions for the pre-carbonization process are: vacuum degree of 0.08 MPa, temperature of 250℃, and time of 10 hours.

[0065] Comparative Example 2

[0066] The present comparative example provides a method for recycling waste crystalline silicon cells, which is basically identical to that of Example 1, except that the conditions for the pre-carbonization process are: vacuum degree of 0 MPa, argon protection, temperature of 350℃, and time of 10 hours.

[0067] Comparative Example 3

[0068] The comparative example 2 provides a preparation method of SiC / AlN composite powder, which is basically identical with the operation of the example 1, except that the undersize after the 400-mesh screen is mixed with graphite according to a mass ratio of 1:1.

[0069] Comparative example 4

[0070] The comparative example 2 provides a preparation method of SiC / AlN composite powder, which is basically identical with the operation of the example 1, except that the undersize after the 400-mesh screen is mixed with graphite according to a mass ratio of 1:1.

[0071] The comparative examples 3 and 4 are subjected to XRD detection, and the results are shown in Figure 2 and Figure 3 According to Figure 2 and Figure 3 , when the undersize after the 400-mesh screen is mixed with graphite according to a mass ratio of 1:1, the content of graphite is excessive and cannot completely participate in the chemical reaction, and the phase test shows that there is graphite; when only the undersize after the 400-mesh screen is sintered, the content of Si is excessive and cannot completely participate in the chemical reaction, and the phase shows that there is Si.

[0072] The pre-carbonization treated materials of the comparative examples 1 and 2 are photographed, and the photographs are shown in Figure 4 and 5 According to Figure 4 and 5 , the color of the EVA glue in the pre-carbonization treated materials according to the examples 3 and 4 is dark brown, and the quality is soft, so that the crushing operation is not easy to be performed.

[0073] The above merely describes the preferred embodiments of the present application, and is not used to limit the present application, and the present application can have various modifications and changes for the person skilled in the art. 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 preparing SiC / AlN composite powder, characterized in that, The method comprises the following steps: The waste silicon wafer with EVA glue is pre-carbonized, then crushed and screened; The EVA after pre-carbonization is still bonded on the silicon wafer and has not fallen off; The pre-carbonization temperature is 280-320℃, the vacuum degree is 0.06-0.08MPa, and the time is 6-10 hours; The screening comprises the following steps: the crushed material is initially screened through 90-110 meshes, and then the undersize material is deeply screened through 400-425 meshes; The undersize material through 400-425 meshes is mixed with graphite-like material and then sintered.

2. The method for preparing SiC / AlN composite powder according to claim 1, characterized in that, The method comprises the following steps: The crushing comprises the following steps: the waste silicon wafer after pre-carbonization is cut into pieces, and then ball-milled or deeply crushed.

3. The method of claim 1, wherein the SiC / AIN composite powder is prepared by the steps of: preparing a SiC / AIN composite powder by mixing SiC powder and AIN powder; and adding a dispersant to the SiC / AIN composite powder. The oversize material through 90-100 meshes and 440-425 meshes is recycled for crushing and screening.

4. The method of claim 1, wherein the SiC / AIN composite powder is prepared by the steps of: preparing a SiC / AIN composite powder by mixing SiC powder and AIN powder; and adding a dispersant to the SiC / AIN composite powder. The mass ratio of the undersize material through 400-425 meshes to the graphite-like material is 2.3-2.4:

1.

5. The method of claim 1, wherein the SiC / AIN composite powder is prepared by the steps of: preparing a SiC / AIN composite powder by mixing SiC powder and AIN powder; and adding a dispersant to the SiC / AIN composite powder. The sintering process comprises the following steps: 450-500℃ for 15-25 minutes, then 1100-1150℃ for 25-35 minutes, then 1250-1350℃ for 100-130 minutes, and then 1450-1500℃ for 100-130 minutes.

6. The method of claim 5, wherein the SiC / AIN composite powder is prepared by the steps of: preparing a SiC / AIN composite powder by mixing SiC powder and AIN powder; and adding a dispersant to the SiC / AIN composite powder. The sintering process comprises the following steps: 450-500℃ for 15-25 minutes at a rate of 3-4℃ / min, then 1100-1150℃ for 25-35 minutes at a rate of 1.5-2℃ / min, then 1250-1350℃ for 100-130 minutes at a rate of 0.5-1℃ / min, and then 1450-1500℃ for 100-130 minutes at a rate of 1-2℃ / min.

7. The method for preparing SiC / AlN composite powder according to any one of claims 1-6, characterized in that, After sintering, the product is naturally cooled.

8. A SiC / AIN composite powder, characterized by, The SiC / AlN composite powder is prepared by the method of any one of claims 1-7.

Images