Perovskite solar cell industrial waste liquid treatment system and treatment method

Abstract

The present invention relates to a perovskite solar cell industrial waste liquid treatment system, comprising a waste liquid tank, a first reaction tank, a second reaction tank, and a solid collection tank. The industrial waste liquid to be treated is stored in the waste liquid tank. The first reaction tank receives a first supernatant and fractionates it to recover an organic solvent. The second reaction tank receives a second supernatant and fractionates it to recover an organic solvent. One end of a solid discharge pipeline is connected to the solid discharge end of the waste liquid tank, and the other end is connected to a solid collection tank. The solid collection tank collects the dried precipitated solids in the waste liquid tank. A heating and drying device is used to heat the waste liquid in the waste liquid tank after adding a second treatment liquid, and to dry the remaining precipitate after discharging the second supernatant. The present invention also discloses a perovskite solar cell industrial waste liquid treatment method. The present invention recycles perovskite component compounds and solvents in the perovskite solar cell industrial waste liquid, thereby improving waste liquid utilization and reducing costs.

Description

Technical Field

[0001] The present invention belongs to the technical field of perovskite solar cell resource recycling and reuse, and in particular relates to a perovskite solar cell industrial waste liquid treatment system and a treatment method thereof. Background Art

[0002] Perovskite solar cells are a popular third-generation solar cell. Their structure consists of a thick perovskite absorber layer sandwiched between two hole and electron transport layers, each of which is connected to a positive and negative electrode. The primary raw materials for perovskite solar cells are lead salts such as PbI2, PbAC2, and PbCl2, and organic components such as methylamine hydroiodide (MAI), formamidine hydroiodide (FAI), and cesium iodide (CsI). The solvents used are primarily N-N-dimethylformamide, dimethoxyethanol, γ-butyrolactone, and trace amounts of dimethyl sulfoxide and N-methylpyrrolidone.

[0003] The light-absorbing layer of perovskite solar cells is made by solution printing, but the coating machine used for solution printing requires a large amount of additional solution to maintain the vacuum in the coating head chamber. This part of the solution eventually becomes waste liquid in the perovskite solar cell industrial production. This waste liquid mainly contains the compounds in the above-mentioned production raw materials.

[0004] Currently, the waste liquid is generally disposed of directly. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to provide a perovskite solar cell industrial waste liquid treatment system and a treatment method thereof, so as to recycle the perovskite component compounds and solvents in the industrial waste liquid produced by perovskite solar cells, thereby improving the utilization rate of the waste liquid, reducing costs, and avoiding wastewater pollution to the environment.

[0006] The present invention is implemented as follows: a perovskite solar cell industrial waste liquid treatment system is provided, comprising a waste liquid tank, a first reaction tank, a second reaction tank and a solid collection tank, wherein the industrial waste liquid to be treated is stored in the waste liquid tank, the first reaction tank receives a first supernatant and fractionates it to recover a reusable organic solvent, the second reaction tank receives a second supernatant and fractionates it to recover a reusable organic solvent, the first supernatant comprises a solution obtained by adding a first treatment liquid to the waste liquid in the waste liquid tank and allowing it to settle, the second supernatant comprises a solution obtained by adding a second treatment liquid to the waste liquid in the waste liquid tank and allowing it to settle, and a solution obtained by adding a third treatment liquid to the waste liquid in the waste liquid tank and allowing it to settle, and an industrial waste liquid feed pipeline, a first treatment liquid feed pipeline, a second treatment liquid feed pipeline, a third treatment liquid feed pipeline, a first supernatant liquid discharge pipeline, and a second supernatant liquid discharge pipeline are respectively provided on the waste liquid tank. A pipeline, a solid discharge pipeline and a heating and drying device, one end of the first supernatant discharge pipeline is connected to the supernatant discharge port of the waste liquid tank, and the other end thereof is connected to the feed end of the first reaction tank, one end of the second supernatant discharge pipeline is also connected to the supernatant discharge port of the waste liquid tank, and the other end thereof is connected to the feed end of the second reaction tank, a first fractionating device and a second fractionating device are respectively provided on the first reaction tank and the second reaction tank, and a plurality of collecting pipelines for collecting the fractionated solvent are respectively provided on the discharge ends of the first reaction tank and the second reaction tank, one end of the solid discharge pipeline is connected to the solid discharge end of the waste liquid tank, and the other end thereof is connected to the solid collecting tank, the solid collecting tank collects the precipitated solid after drying in the waste liquid tank, and the heating and drying device is used for heating the waste liquid in the waste liquid tank after adding the second treatment liquid and drying the remaining precipitate after discharging the second supernatant.

[0007] Furthermore, the perovskite solar cell industrial waste liquid treatment system also includes a first recovery pipeline and a second recovery pipeline, one end of the first recovery pipeline is connected to the feed end of the waste liquid tank, and the other end thereof is connected to the discharge end of the first reaction tank. The first recovery pipeline is used to recover the precipitate after distillation of the first reaction tank into the waste liquid tank for reuse, and one end of the second recovery pipeline is connected to the feed end of the waste liquid tank, and the other end thereof is connected to the discharge end of the second reaction tank. The second recovery pipeline is used to recover the precipitate after distillation of the second reaction tank into the waste liquid tank for reuse.

[0008] Furthermore, the first treatment liquid includes ethanol or isopropanol, and the added amount of the first treatment liquid is between 100% and 150% by volume of the waste liquid; the second treatment liquid is any one of dimethoxyethanol, γ-butyrolactone (GBL) or 1-cyclohexyl-2-pyrrolidone, and iodomethane (FAI) or iodine methylamine (MAI), wherein the added amount of dimethoxyethanol is between 50% and 90% by volume of the waste liquid, the added amount of γ-butyrolactone (GBL) is between 50% and 90% by volume of the waste liquid, the added amount of 1-cyclohexyl-2-pyrrolidone is between 0% and 10% by volume of the waste liquid, and the added amount of iodomethane (FAI) or iodine methylamine (MAI) is between 0% and 100% by volume of the waste liquid; the third treatment liquid is isopropanol or chlorobenzene.

[0009] Furthermore, the reusable organic solvent recovered by fractionation in the first reaction tank includes ethanol or isopropanol, dimethoxyethanol, NN dimethylformamide and γ-butyrolactone, and the reusable organic solvent recovered by fractionation in the second reaction tank includes isopropanol, dimethoxyethanol, chlorobenzene, 1-cyclohexyl-2-pyrrolidone and γ-butyrolactone.

[0010] Furthermore, a stirring device is provided in the waste liquid tank.

[0011] The present invention is implemented by providing a method for treating industrial waste liquid from perovskite solar cells, comprising the following steps:

[0012] Step 1: The perovskite solar cell industrial waste liquid enters the waste liquid tank through the industrial waste liquid feed pipe, the first treatment liquid is added to the waste liquid tank through the first treatment liquid feed pipe, and the solution in the waste liquid tank is allowed to precipitate, and then the solution is allowed to stand and separate to obtain a first supernatant at the top and a first precipitate at the bottom;

[0013] Step 2: The separated first supernatant is transported to the first reaction tank through the first supernatant discharge pipeline, and the first precipitate is still retained in the waste liquid tank. The first supernatant in the first reaction tank is fractionally distilled by the first fractionating device, and the reusable organic solvent obtained after the distillation is recovered through multiple collection pipelines. At the same time, the precipitate remaining after the fractionation is fed into the waste liquid tank through the first recovery pipeline for reuse;

[0014] Step 3: Then, add the second treatment liquid to the waste liquid tank through the second treatment liquid feed pipe, use the stirring device to stir the solution in the waste liquid tank, use the heating and drying device to heat the solution, and the solution in the waste liquid tank reacts to produce a large amount of black precipitate and then stands, and separates the second supernatant at the top and the second precipitate at the bottom; the second supernatant is transported to the second reaction tank through the second supernatant discharge pipe, and the second precipitate is retained in the waste liquid tank, and the third treatment liquid is added to the waste liquid tank through the third treatment liquid feed pipe, the second precipitate is washed, and then the washing solution is stirred using the stirring device, and the solution is stood, waiting for the black solid in the waste liquid tank to re-precipitate at the bottom of the tank body, and then the third supernatant at the top and the third precipitate at the bottom are separated, and the third supernatant is also transported to the second reaction tank through the second supernatant discharge pipe; the remaining precipitate in the waste liquid tank is heated and dried using the heating and drying device, and the precipitated solid obtained is the perovskite solid that can be reused for perovskite light absorbing layer processing;

[0015] Step 4: fractionate the mixture of the second supernatant and the third supernatant in the second reaction tank through a second fractionation device, recover the reusable organic solvent obtained after the distillation through multiple collection pipelines, and at the same time feed the precipitate remaining after the fractionation treatment into the waste liquid tank through the second recovery pipeline for reuse.

[0016] Furthermore, in step three, the temperature of the heating reaction of the solution in the waste liquid tank is controlled at 50°C to 100°C using a heating and drying device.

[0017] Compared with the existing technology, the perovskite solar cell industrial waste liquid treatment system and treatment method of the present invention can convert the halide lead compounds in the perovskite solar cell waste liquid into perovskite components for reuse in the preparation of the perovskite light-absorbing layer. At the same time, it can recycle various organic solvents in the waste liquid, improve the utilization rate of raw materials, effectively reduce the production cost of perovskite solar cells, and avoid wastewater pollution of the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] Figure 1 This is a schematic diagram of the principle of a preferred embodiment of the novel perovskite solar cell industrial waste liquid treatment system of the present invention. DETAILED DESCRIPTION

[0019] In order to make the technical problems, technical solutions and beneficial effects to be solved by the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0020] Please refer to Figure 1As shown in FIG. 1 , a preferred embodiment of the perovskite solar cell industrial wastewater treatment system of the present invention comprises a wastewater tank 1, a first reaction tank 2, a second reaction tank 3, and a solid collection tank 4. The arrows in the figure indicate the flow direction of raw materials or materials in the system.

[0021] The industrial waste liquid to be treated is stored in a waste liquid tank 1. The first reaction tank 2 receives a first supernatant and fractionally distills it to recover a reusable organic solvent. The second reaction tank 3 receives a second supernatant and fractionally distills it to recover a reusable organic solvent. The first supernatant comprises a solution obtained by adding the first treatment liquid to the waste liquid in the waste liquid tank 1 and allowing it to settle. The second supernatant comprises a solution obtained by adding the second treatment liquid and allowing it to settle, and a solution obtained by adding the third treatment liquid and allowing it to settle, to the waste liquid in the waste liquid tank 1.

[0022] The waste liquid tank 1 is respectively provided with an industrial waste liquid feed pipeline 5, a first treatment liquid feed pipeline 6, a second treatment liquid feed pipeline 7, a third treatment liquid feed pipeline 8, a first supernatant liquid discharge pipeline 9, a second supernatant liquid discharge pipeline 10, a solid discharge pipeline 11, a heating and drying device 12, a first recovery pipeline 13 and a second recovery pipeline 14. The industrial waste liquid feed pipeline 5, the first treatment liquid feed pipeline 6, the second treatment liquid feed pipeline 7 and the third treatment liquid feed pipeline 8 are respectively provided at the feed end of the waste liquid tank 1.

[0023] One end of the first supernatant discharge line 9 is connected to the supernatant discharge port 16 of the waste liquid tank 1, and the other end is connected to the feed end of the first reaction tank 2. One end of the second supernatant discharge line 10 is also connected to the supernatant discharge port 16 of the waste liquid tank 1, and the other end is connected to the feed end of the second reaction tank 3. A first fractionation device and a second fractionation device (not shown) are respectively installed on the first reaction tank 2 and the second reaction tank 3. Multiple collection lines 17 for collecting the fractionated solvent are respectively installed on the discharge ends of the first reaction tank 2 and the second reaction tank 3. Each collection line 17 collects a corresponding organic solvent.

[0024] One end of the solid discharge pipe 11 is connected to the solid discharge port of the waste liquid tank 1, and the other end is connected to the solid collection tank 4. The solid collection tank 4 collects the dried precipitated solids in the waste liquid tank 1. This precipitated solid is the perovskite solid used to prepare the perovskite solar cell. The heating and drying device 12 is used to heat the waste liquid in the waste liquid tank 1 after adding the second treatment liquid and to dry the remaining precipitate after discharging the second supernatant.

[0025] One end of the first recovery line 13 is connected to the feed end of the waste liquid tank 1, and the other end is connected to the discharge end of the first reaction tank 2. The first recovery line 13 is used to recover the precipitate after distillation in the first reaction tank 2 and reuse it in the waste liquid tank 1. One end of the second recovery line 14 is connected to the feed end of the waste liquid tank 1, and the other end is connected to the discharge end of the second reaction tank 3. The second recovery line 14 is used to recover the precipitate after distillation in the second reaction tank 3 and reuse it in the waste liquid tank 1.

[0026] The first treatment liquid includes ethanol or isopropanol, and the added amount of the first treatment liquid is such that the volume ratio of the first treatment liquid to the waste liquid is between 100% and 150%.

[0027] The second treatment liquid is any one of dimethoxyethanol, γ-butyrolactone (GBL) or 1-cyclohexyl-2-pyrrolidone, and iodomethane (FAI) or iodine methylamine (MAI), wherein the added amount of dimethoxyethanol is between 50% and 90% by volume of the waste liquid, the added amount of γ-butyrolactone (GBL) is between 50% and 90% by volume of the waste liquid, the added amount of 1-cyclohexyl-2-pyrrolidone is between 0% and 10% by volume of the waste liquid, and the added amount of iodomethane (FAI) or iodine methylamine (MAI) is between 0% and 100% by volume of the waste liquid.

[0028] The third treatment liquid is isopropyl alcohol or chlorobenzene. The third treatment liquid is used to wash the second precipitate. The amount of the third treatment liquid used is determined by the operator according to the precipitate washing situation.

[0029] The reusable organic solvent recovered by fractionation in the first reaction tank 2 includes ethanol or isopropanol, dimethoxyethanol, NN dimethylformamide and γ-butyrolactone, and the reusable organic solvent recovered by fractionation in the second reaction tank 3 includes isopropanol, dimethoxyethanol, chlorobenzene, 1-cyclohexyl-2-pyrrolidone and γ-butyrolactone.

[0030] A stirring device 15 is provided in the waste liquid tank for stirring the solution in the waste liquid tank 1 to allow it to react fully.

[0031] The present invention also discloses a method for treating industrial waste liquid from a perovskite solar cell, which utilizes the aforementioned industrial waste liquid treatment system from a perovskite solar cell to treat the waste liquid. The method comprises the following steps:

[0032] Step 1: The industrial waste liquid of the perovskite solar cell enters the waste liquid tank 1 through the industrial waste liquid feed pipe 5, and the first treatment liquid is added to the waste liquid tank 1 through the first treatment liquid feed pipe 6. Wait for the solution in the waste liquid tank 1 to precipitate, and then stand to separate the first supernatant at the top and the first precipitate at the bottom.

[0033] The components of the first precipitate are mainly lead salts such as PbI2, PbAC2, PbCl2 and organic components such as methylamine hydroiodide MAI, formamidine hydroiodide FAI, cesium iodide CsI, and compound salts of the combination of the two.

[0034] The main components of the first supernatant are organic solvents such as N-N-dimethylformamide, dimethoxyethanol, γ-butyrolactone in the raw materials for producing perovskite solar cells and the first treatment liquid just added in step 1, such as ethanol or isopropanol.

[0035] The volume ratio of the first treatment liquid added to the waste liquid is between 100% and 150%.

[0036] In step 2, the separated first supernatant is transported to the first reaction tank 2 via the first supernatant discharge line 9, while the first precipitate remains in the waste liquid tank 1. The first supernatant in the first reaction tank 2 is fractionated by the first fractionating device, and the reusable organic solvent obtained after the fractionation is recovered through multiple collection lines 17. At the same time, the precipitate remaining after the fractionation is fed into the waste liquid tank 1 through the first recovery line 13 for reuse.

[0037] The step of fractionating to obtain a reusable organic solvent includes: by setting the fractionation temperature, recovering ethanol at about 78°C, recovering isopropanol at about 82°C, recovering dimethoxyethanol at about 124°C, recovering N-N-dimethylformamide at about 153°C, and recovering γ-butyrolactone at about 204°C.

[0038] The composition of the precipitate left after fractionation treatment is similar to the first precipitation, and will not be repeated here.Step 3, then, by the second treatment liquid feed pipeline 7, in waste liquid tank 1, add the second treatment liquid, use agitating device 15 to stir the solution in waste liquid tank 1, use heating drying device 12 to heat solution, the solution reaction in waste liquid tank 1 is produced and leaves standstill after a large amount of black precipitates, and static separation goes out the second supernatant liquor in top and the second precipitation in bottom.The second supernatant liquor is transported in the second reactor 3 by the second supernatant liquor discharging pipeline 10, and the second precipitation is then retained in the waste liquid tank 1, by the third treatment liquid feed pipeline 8, in waste liquid tank 1, add the third treatment liquid, the second precipitation is cleaned, and then agitating device is used to stir cleaning solution, leave standstill, wait for the black solid in waste liquid tank to be again deposited on the bottom of tank body and separate the third supernatant liquor in top and the third precipitation in bottom, the third supernatant liquor is also transported in the second reactor 3 by the second supernatant liquor discharging pipeline 10. The heating and drying device 12 is used to heat and dry the remaining precipitate in the waste liquid tank 1, and the obtained precipitated solid is the perovskite solid that can be reused in the processing of the perovskite light absorbing layer.

[0039] The second treatment liquid is any one of dimethoxyethanol, γ-butyrolactone or 1-cyclohexyl-2-pyrrolidone, and iodomethane or iodine methylamine, wherein the added amount of dimethoxyethanol is between 50% and 90% by volume of the waste liquid, the added amount of γ-butyrolactone is between 50% and 90% by volume of the waste liquid, the added amount of 1-cyclohexyl-2-pyrrolidone is between 0% and 10% by volume of the waste liquid, and the added amount of iodomethane or iodine methylamine is between 0% and 100% by volume of the waste liquid.

[0040] The main components of the second precipitate and the third precipitate (i.e., black precipitate) are mixed cation perovskites of FA, MA, and Cs. The specific general formula can be written as FA a MA b Cs (1-a-b) PbX2, X can be I-, Cl-, Ac, etc., where 0≤a≤1, 0≤b≤1. The second and third precipitates can be recycled and reused to prepare the light-absorbing layer raw materials of perovskite solar cells, thereby improving the utilization rate of industrial wastewater of perovskite solar cells and reducing costs.

[0041] The third treatment liquid is isopropyl alcohol or chlorobenzene. The third treatment liquid is used to wash the second precipitate. The amount of the third treatment liquid used is determined by the operator according to the precipitate washing situation.

[0042] The main components of the mixture of the second supernatant and the third supernatant are the second treatment liquid and the third treatment liquid added in this step.

[0043] Step 4: The mixed liquid of the second supernatant and the third supernatant in the second reaction tank 3 is fractionated by a second fractionating device, and the reusable organic solvent obtained after the distillation is recovered through multiple collection pipes 17. At the same time, the precipitate remaining after the fractionation treatment is fed into the waste liquid tank 1 through the second recovery pipe 14 for reuse.

[0044] The step of fractionating to obtain a reusable organic solvent includes: by setting the fractionation temperature, recovering isopropyl alcohol at about 82°C, recovering dimethoxyethanol at about 124°C, recovering chlorobenzene at about 132°C, recovering 1-cyclohexyl-2-pyrrolidone at about 154°C, and recovering gamma-butyrolactone at about 204°C.

[0045] The precipitate remaining after the fractionation treatment is similar to the second precipitate and the third precipitate in step 3 and will not be described in detail.

[0046] In step three, the solution in the waste liquid tank 1 is heated by a heating and drying device 12 at a temperature of 50° C. to 100° C. The purpose of heating is to promote the reaction to form a second precipitate, thereby obtaining a recyclable perovskite raw material.

[0047] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A perovskite solar cell industrial wastewater treatment system, characterized in that: The invention comprises a waste liquid tank, a first reaction tank, a second reaction tank and a solid collection tank. The industrial waste liquid to be treated is stored in the waste liquid tank. The first reaction tank receives the first supernatant and fractionates it to recover the reusable organic solvent. The second reaction tank receives the second supernatant and fractionates it to recover the reusable organic solvent. The first supernatant comprises a solution obtained by adding the first treatment liquid to the waste liquid in the waste liquid tank and allowing it to settle. The second supernatant comprises a solution obtained by adding the second treatment liquid and allowing it to settle and a solution obtained by adding the third treatment liquid to the waste liquid in the waste liquid tank and allowing it to settle. An industrial waste liquid feeding pipeline, a first treatment liquid feeding pipeline, a second treatment liquid feeding pipeline, a third treatment liquid feeding pipeline, a first supernatant liquid discharging pipeline, a second supernatant liquid discharging pipeline, a solid discharging pipeline and a heating and drying device are respectively arranged on the waste liquid tank. , one end of the first supernatant liquid discharge pipeline is connected to the supernatant liquid discharge port of the waste liquid tank, and the other end thereof is connected to the feed end of the first reaction tank, one end of the second supernatant liquid discharge pipeline is also connected to the supernatant liquid discharge port of the waste liquid tank, and the other end thereof is connected to the feed end of the second reaction tank, a first fractionating device and a second fractionating device are respectively provided on the first reaction tank and the second reaction tank, and a plurality of collection pipelines for collecting the fractionated solvent are respectively provided on the discharge ends of the first reaction tank and the second reaction tank, one end of the solid discharge pipeline is connected to the solid discharge end of the waste liquid tank, and the other end thereof is connected to the solid collecting tank, the solid collecting tank collects the precipitated solid after drying in the waste liquid tank, and the heating and drying device is used to heat the waste liquid in the waste liquid tank after adding the second treatment liquid and to dry the remaining precipitate after discharging the second supernatant; The perovskite solar cell industrial waste liquid treatment system also includes a first recovery pipeline and a second recovery pipeline, one end of the first recovery pipeline is connected to the feed end of the waste liquid tank, and the other end thereof is connected to the discharge end of the first reaction tank, and the first recovery pipeline is used to recover the precipitate after distillation in the first reaction tank to the waste liquid tank for reuse, and one end of the second recovery pipeline is connected to the feed end of the waste liquid tank, and the other end thereof is connected to the discharge end of the second reaction tank, and the second recovery pipeline is used to recover the precipitate after distillation in the second reaction tank to the waste liquid tank for reuse; The first treatment liquid includes ethanol or isopropanol, and the amount of the first treatment liquid added is such that the volume ratio of the first treatment liquid to the waste liquid is between 100% and 150%; the second treatment liquid is any one of dimethoxyethanol, γ-butyrolactone or 1-cyclohexyl-2-pyrrolidone and iodoformamidine or iodomethylamine, wherein the amount of dimethoxyethanol added is such that the volume ratio of the first treatment liquid to the waste liquid is between 50% and 90%, the amount of γ-butyrolactone added is such that the volume ratio of the first treatment liquid to the waste liquid is between 50% and 90%, the amount of 1-cyclohexyl-2-pyrrolidone added is such that the volume ratio of the first treatment liquid to the waste liquid is between 0% and 10%, and the amount of iodoformamidine or iodomethylamine added is such that the volume ratio of the first treatment liquid to the waste liquid is between 0% and 100%; the third treatment liquid is isopropanol or chlorobenzene; The reusable organic solvent recovered by fractionation in the first reaction tank includes ethanol or isopropanol, dimethoxyethanol, NN dimethylformamide and γ-butyrolactone, and the reusable organic solvent recovered by fractionation in the second reaction tank includes isopropanol, dimethoxyethanol, chlorobenzene, 1-cyclohexyl-2-pyrrolidone and γ-butyrolactone.

2. The perovskite solar cell industrial wastewater treatment system according to claim 1, characterized in that: A stirring device is provided in the waste liquid tank.

3. A method for treating industrial wastewater from perovskite solar cells, characterized in that: The perovskite solar cell industrial waste liquid treatment system according to claim 1 or 2 is used, and the method comprises the following steps: Step 1: The perovskite solar cell industrial waste liquid enters the waste liquid tank through the industrial waste liquid feed pipe, the first treatment liquid is added to the waste liquid tank through the first treatment liquid feed pipe, and the solution in the waste liquid tank is allowed to precipitate, and then the solution is allowed to stand and separate to obtain a first supernatant at the top and a first precipitate at the bottom; Step 2: The separated first supernatant is transported to the first reaction tank through the first supernatant discharge pipeline, and the first precipitate is still retained in the waste liquid tank. The first supernatant in the first reaction tank is fractionally distilled by the first fractionating device, and the reusable organic solvent obtained after the distillation is recovered through multiple collection pipelines. At the same time, the precipitate remaining after the fractionation is fed into the waste liquid tank through the first recovery pipeline for reuse; Step 3: Then, add the second treatment liquid to the waste liquid tank through the second treatment liquid feed pipe, use the stirring device to stir the solution in the waste liquid tank, use the heating and drying device to heat the solution, and the solution in the waste liquid tank reacts to produce a large amount of black precipitate and then stands, and separates the second supernatant at the top and the second precipitate at the bottom; the second supernatant is transported to the second reaction tank through the second supernatant discharge pipe, and the second precipitate is retained in the waste liquid tank, and the third treatment liquid is added to the waste liquid tank through the third treatment liquid feed pipe, the second precipitate is washed, and then the washing solution is stirred using the stirring device, and the solution is stood, waiting for the black solid in the waste liquid tank to re-precipitate at the bottom of the tank body, and then the third supernatant at the top and the third precipitate at the bottom are separated, and the third supernatant is also transported to the second reaction tank through the second supernatant discharge pipe; the remaining precipitate in the waste liquid tank is heated and dried using the heating and drying device, and the precipitated solid obtained is the perovskite solid that can be reused for perovskite light absorbing layer processing; Step 4: fractionate the mixture of the second supernatant and the third supernatant in the second reaction tank through a second fractionation device, recover the reusable organic solvent obtained after the distillation through multiple collection pipelines, and at the same time feed the precipitate remaining after the fractionation treatment into the waste liquid tank through the second recovery pipeline for reuse.

4. The method for treating industrial waste liquid from perovskite solar cells according to claim 3, wherein: The first treatment liquid includes ethanol or isopropanol, and the added amount of the first treatment liquid is between 100% and 150% by volume of the waste liquid; the second treatment liquid is any one of dimethoxyethanol, γ-butyrolactone or 1-cyclohexyl-2-pyrrolidone, and iodoformamidine or iodomethylamine, wherein the added amount of dimethoxyethanol is between 50% and 90% by volume of the waste liquid, the added amount of γ-butyrolactone is between 50% and 90% by volume of the waste liquid, the added amount of 1-cyclohexyl-2-pyrrolidone is between 0% and 10% by volume of the waste liquid, and the added amount of iodoformamidine or iodomethylamine is between 0% and 100% by volume of the waste liquid; the third treatment liquid is isopropanol or chlorobenzene.

5. The method for treating industrial waste liquid from perovskite solar cells according to claim 3, wherein: The reusable organic solvent recovered by fractionation in the first reaction tank includes ethanol or isopropanol, dimethoxyethanol, NN dimethylformamide and γ-butyrolactone, and the reusable organic solvent recovered by fractionation in the second reaction tank includes isopropanol, dimethoxyethanol, chlorobenzene, 1-cyclohexyl-2-pyrrolidone and γ-butyrolactone.

6. The method for treating industrial waste liquid from perovskite solar cells according to claim 3, wherein: In step three, a heating and drying device is used to heat the solution in the waste liquid tank and the temperature of the reaction is controlled at 50°C to 100°C.

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