Method for catalytic separation and high-value utilization of fluorine-containing organic binder of retired new energy device

Abstract

Disclosed in the present invention is a method for the catalytic separation and high-value utilization of a fluorine-containing organic binder of a retired new energy device. The method comprises the following steps: preparation of a rare-earth photocatalytic material, depolymerization and stripping via photo-thermal catalysis, lanthanum extraction via acid leaching, low-temperature fluorine precipitation, and solid phosphorus purification via heating. In the present invention, hydroxyl groups are used to attack carbon-fluorine bonds in the organic binder to prepare a photocatalyst, implementing one-step photo-thermal-catalyzed depolymerization of the organic binder and replacing multiple traditional process steps such as mechanical crushing, sorting, and strong acid and alkali leaching, not only avoiding the use of toxic and harmful solvents and directionally preparing toxic elements in the binder into high-value products, but also achieving the effect of recycling both the spent catalyst and the retired energy device by directionally preparing catalyst types, thus providing a safe, efficient, and economical means of solid waste disposal and clean new materials synthesis for retired new energy device recycling and advanced materials manufacturing.

Description

A method for catalytic separation and high-value utilization of fluorinated organic binders in retired new energy devices Technical field:

[0001] The present invention relates to a three-phase waste comprehensive disposal technology in the process of stripping and recycling organic binders of retired new energy devices, and specifically to a method for catalytic separation and high-value utilization of fluorinated organic binders of retired new energy devices. Background technology:

[0002] Retired new energy devices include waste lithium-ion battery electrode materials, waste circuit boards, and waste photovoltaic panels. Fluorinated organic binders such as polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorinated styrene-butadiene rubber (SBRF), and fluorinated carboxymethyl cellulose (CMCF) are commonly used to bond the device components. Ultrasonic-assisted organic solvent "like dissolves like" binders, high-temperature-assisted strong acid-base dissolution, and mechanical crushing and physical separation are commonly used to remove the organic binders for recycling pretreatment. Organic solvents, such as N-methylpyrrolidone and dimethylformamide, effectively remove high-value components while recovering intact low-value components. However, the cost of organic solvents and the harsh low-temperature reaction conditions pose significant health risks to operators. High-temperature-assisted strong acid-base dissolution exploits the differential solubility of two components to remove the high-value component and is a commonly used method in laboratories and industrial production lines. However, fluorinated organic binders and other organic components emit large amounts of toxic and harmful gases at high temperatures, and strong acid-base systems corrode reaction equipment and produce saline wastewater. Although mechanical crushing and physical sorting methods pose less environmental risk, the product often contains a large number of low-value components, which increases the difficulty of subsequent removal and purification of high-value impurities and requires further processing. Publication No. CN116136022A discloses a stripping agent, stripping liquid composition, and a stripping method for waste lithium-ion battery electrode materials. After cutting the waste lithium-ion battery cells into fragments, organic acid is used to effectively separate the positive electrode material from the aluminum foil and the negative electrode material from the copper foil. Corrosion inhibitors are further used to improve the component recovery rate. Although the recovery rate and purity of the positive and negative electrode materials can reach over 99% by this method, the entire system requires multi-stage stripping and will emit a large amount of sulfur-containing wastewater and hydrogen. The by-products of the reaction system are cheap, making it difficult to achieve a green, safe and stable recovery process, and it is difficult to guarantee economic efficiency and safety. Publication number CN115871045A discloses a control system and control method for a photovoltaic panel hot knife stripping device. It uses a high-temperature hot knife to mechanically strip the back panel glass and battery silicon wafer film in the photovoltaic panel, which can effectively strip fluorine-containing organic matter and high-value components. However, the fluorine-containing organic matter will stick to the blade during the hot knife stripping, greatly limiting the stripping efficiency of industrial production.

[0003] Based on the above analysis, whether it is possible to depolymerize the fluorine-containing binder on the surface of high-value components of retired new energy devices and strip off the high-value components, while achieving high-quality utilization of the low-value by-products generated in the process, is of great significance to the efficient stripping and recycling of energy devices.

[0004] Therefore, it is necessary to develop a new low-energy, low-pollution and low-cost energy device stripping method to solve the problem of lossless stripping of high-value components of energy devices and high-value utilization of all components during the stripping process. Summary of the invention:

[0005] The present invention provides a method for catalytic separation and high-value utilization of fluorine-containing organic binders in retired new energy devices. Based on the chemical property that photocatalysis can achieve depolymerization of organic matter under mild conditions, and coupling the characteristics and principles of rare earth metal lanthanum with toxic elements such as fluorine and phosphorus to more easily generate high-value chemicals, the depolymerization and stripping of high-value components of energy devices and organic binders are achieved under photothermal reaction conditions, and the directional enrichment and purification of depolymerized toxic elements such as fluorine and phosphorus are simultaneously achieved. It not only solves the problems of low stripping rate of mechanical crushing and physical sorting methods and the discharge of toxic reactants and salt-containing wastewater in strong acid and alkali systems by chemical solvent methods, but also achieves the effect of no waste generation and high-value utilization of by-products in the entire process through coupling waste photocatalyst recovery and optical material preparation, and solves the problems of difficulty, high cost, high energy consumption, and toxic and low-quality stripping of organic binders in the recovery process of high-value components of new energy devices.

[0006] A method for catalytic stripping and high-value utilization of fluorinated organic binders of retired new energy devices, comprising the following steps:

[0007] (1) Preparation of rare earth photocatalytic materials: lanthanide metal oxide, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high temperature reaction at 400℃~450℃ for 7~12h. The molar ratio of lanthanide metal oxide, 4-isopropylbenzoic acid and ethylene carbonate was 1:1.4:1~1.5. The solution after the high temperature reaction was centrifuged at 2℃~7℃, dried, washed with ethanol and water for many times, and then calcined at 400~500℃ under nitrogen for 15~26h to obtain a MOF catalyst carrier, named R-MOF, where R represents the type of lanthanide metal, selected from one of La, Ce, Pr, Nd, Sm and Eu. R-MOF, titanium tetra-n-butoxide and oxalic acid were added to deionized water and transferred to a rotary evaporator. The vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material R-MOF@TiO2; the mass ratio of R-MOF, titanium tetra-n-butoxide and oxalic acid is 1:3:0.4-1.4g / g;

[0008] (2) Photothermal catalytic depolymerization and stripping: the R-MOF@TiO2 obtained in step (1) and the retired new energy device are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and enhanced stirring to achieve depolymerization of the fluorine-containing organic binder in the retired energy device, thereby obtaining a high-value component monomer of the energy material device and a fluorine-containing phosphorus mixed gas, and the high-value component monomer is returned to the energy device for regeneration; the light exposure, high temperature, low pressure and enhanced stirring, the xenon lamp light source has a luminous spectrum wavelength range of 300nm to 350nm, and a light intensity range of 120mW / cm 2 ~220mW / cm 2 , temperature is 110~140℃, nitrogen pressure is 0.05MPa~0.29MPa, enhanced stirring speed is 260rpm~385rpm, and stirring time is 3h~13h;

[0009] (3) Acid leaching of lanthanum: The R-MOF@TiO4 with low catalytic efficiency obtained in step (2) is acid-leached multiple times to obtain a lanthanum-rich leachate and titanium-rich slag, and the titanium-rich slag is returned to the electroplating solution production process;

[0010] (4) low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain fluorine-containing lanthanum slag, defluorination residual liquid and mixed gas; the mixed gas contains H2, CH4 and C2H6;

[0011] (5) Heating and purifying phosphorus fixation: The defluorinated residual solution obtained in step (4) is adjusted to a pH value of 1 to 2 with 75 to 80% H3PO4 by mass, and the temperature is raised to 80°C to 90°C to obtain phosphorus lanthanum slag. The phosphorus lanthanum slag is purified by alcohol washing and negative pressure heating volatilization to obtain high-purity RPO4, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse.

[0012] Preferably, the retired new energy devices include one of waste lithium-ion battery electrode materials, waste circuit boards and waste photovoltaic panels, and the fluorine-containing organic binder is one of polyvinylidene fluoride (PVDF), polytetrafluoroethylene (PTFE), fluorinated styrene-butadiene rubber (SBRF) and fluorinated carboxymethyl cellulose (CMCF), preferably polyvinylidene fluoride (PVDF).

[0013] Preferably, the low-temperature centrifugation speed in step (1) is 500-1000 rpm.

[0014] Preferably, the mass ratio of the R-MOF@TiO2, retired new energy devices and isopropanol in step (2) is 1:10:22.7 to 1:10:29.

[0015] Preferably, the acid in step (3) is 0.1M to 2.1M H3PO4, and the stirring speed of the enhanced leaching is 300rpm to 425rpm.

[0016] Preferably, the flow rate of the fluorine-phosphorus mixed gas in step (4) is 10 mL / min to 20 mL / min, the temperature is 35 to 60° C., and the pH value ranges from 4 to 5.8.

[0017] Preferably, the alcohol washing in step (5) is performed with ethanol having a mass concentration of 70% to 85%, the insulation temperature is 120° C. to 145° C., the vacuum pressure is 2 to 5 Pa, and the insulation time is 1 to 6 hours.

[0018] Preferably, the high-value component monomers obtained in step (2) are returned to the energy device regeneration process; and the titanium-rich slag obtained in step (3) is returned to the electroplating solution production process.

[0019] Compared with the prior art, the present invention has the following advantages:

[0020] 1. Compared with the traditional methods of stripping organic binders by using ultrasound-assisted organic solvents for "similar dissolution" of binders, high-temperature-assisted strong acid and alkali dissolution, and mechanical crushing and physical sorting, the present invention uses lanthanide metal oxides and titanium dioxide and other low-cost and stable metal oxides to prepare rare earth photocatalytic materials R-MOF@TiO2, and utilizes the rich structure and ultra-large specific surface area of ​​MOF materials to provide rich reaction active sites for auxiliary photothermal reaction conditions to promote the depolymerization and stripping of organic binders. Then, through the step-by-step directional precipitation of fluorine and phosphorus by lanthanide metal oxides, the waste photocatalyst is acid-leached to reuse the lanthanum-rich leachate in the system, which can reduce the subsequent impurity element removal steps caused by the introduction of other elements and improve the removal rate of two toxic elements, fluorine and phosphorus. It has the advantages of mild reaction conditions, environmentally friendly reaction system, and high stripping rate.

[0021] 2. This invention uses photothermal catalysis to attack the carbon-fluorine bonds in fluorinated organic binders (such as PVDF) using isopropyl alcohol hydroxyl groups, leading to depolymerization and defluorination of the fluorinated organic binder. The coupled reaction generates gas that expands the distance between the fluorinated organic binder and the energy device, enabling the separation of the fluorinated organic binder and the energy device components. Furthermore, lanthanide metal compounds enriched with toxic elements such as fluorine and phosphorus more easily form insoluble, stable compounds, achieving a higher toxic element removal rate.

[0022] 3. The reuse of waste rare earth catalysts and the high-value utilization of products throughout the entire process provide a new method for the synthesis of precursors for high-value optical materials while reducing rare earth mineral mining, providing a new path for the resource utilization and high-value utilization of waste catalysts. The entire system generates no waste, effectively reducing carbon emissions.

[0023] Therefore, the present invention uses hydroxyl groups to attack the carbon-fluorine bonds in the organic binder to prepare photocatalysts, and realizes one-step photothermal catalytic depolymerization of the organic binder instead of traditional mechanical crushing, sorting, strong acid and alkali leaching and other multi-step processes. It not only avoids the use of toxic and harmful solvents but also directionally prepares high-value products from toxic elements in the binder. It also achieves the effect of jointly recycling waste catalysts and retired energy devices through the targeted preparation of catalyst types. It is particularly suitable for energy device stripping, organic binder stripping and optical material preparation for energy device recycling, and provides a safe, efficient and economical solid waste disposal and new material clean synthesis method for the recycling of retired new energy devices and the manufacture of advanced materials. Description of the drawings:

[0024] FIG1 shows the morphology of the photocatalyst obtained in Example 1 of the present invention.

[0025] FIG2 is an XRD phase composition diagram of the purified lanthanum phosphate obtained in Example 1 of the present invention.

[0026] FIG3 shows the morphology of the purified lanthanum phosphate obtained in Example 1 of the present invention. Specific implementation method:

[0027] The following examples are provided to further illustrate the present invention, but are not intended to limit the present invention.

[0028] Unless otherwise defined, all technical terms used hereinafter have the same meanings as those generally understood by those skilled in the art. The technical terms used herein are for the purpose of describing specific embodiments only and are not intended to limit the scope of protection of the present invention. Unless otherwise specified, the experimental materials and reagents herein are conventional commercial products in the art.

[0029] The technical solutions of the present invention are described clearly and completely below in conjunction with the embodiments of the present invention.

[0030] Example 1

[0031] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0032] (1) Preparation of rare earth photocatalytic materials: La2O3, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high-temperature reaction at 400℃ for 7h. The solution after the high-temperature reaction was centrifuged at 2℃ with a centrifugal speed of 500rpm, then dried, washed with ethanol and water several times, and calcined at 400℃ under nitrogen for 15h to obtain La-MOF. La-MOF, titanium tetra-n-butoxide and oxalic acid with a mass ratio of 1:3:0.4g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material La-MOF@TiO2; wherein the molar ratio of La2O3 to 4-isopropylbenzoic acid and ethylene carbonate is 1:1.4:1.

[0033] (2) Photothermal catalytic depolymerization and stripping: the La-MOF@TiO2 obtained in step (1) and the waste lithium-ion battery electrode material are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and enhanced stirring to achieve depolymerization of PVDF in the waste lithium-ion battery electrode material, thereby obtaining high-value component monomers and fluorine-phosphorus mixed gas of energy material devices, and the high-value component monomers are returned to the energy device for regeneration; wherein the mass ratio of La-MOF@TiO2, waste lithium-ion battery electrode material and isopropanol is 1:10:22.7, the luminescence spectrum wavelength of the xenon lamp light source is 300nm, and the light intensity is 120mW / cm 2 , temperature is 110°C, nitrogen pressure is 0.05 MPa, enhanced stirring speed is 260 rpm, and reaction time is 3 h.

[0034] (3) Acid leaching of lanthanum: The La-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is leached with 0.1M H3PO4, and the stirring speed of the leaching is enhanced at 300 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0035] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can come from the La-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 10 mL / min, the temperature is 35°C, and the pH value is 4.

[0036] (5) Heating and solidifying phosphorus for purification: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 1 with 75% by mass of H₃PO₄ and heated to 80°C to obtain a lanthanum phosphate residue. The lanthanum phosphate residue is purified by alcohol washing and then heated under negative pressure for volatilization to obtain high-purity LaPO₄, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The concentration of the purified ethanol washing is 70%, the holding temperature is 120°C, the vacuum pressure is 2 Pa, and the holding time is 1 hour.

[0037] Example 2

[0038] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0039] (1) Preparation of rare earth photocatalytic materials: CeO2, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high-temperature reaction at 450℃ for 12 hours. The solution after the high-temperature reaction was centrifuged at 7℃ with a centrifugal speed of 1000 rpm. Then, it was dried, washed with ethanol and water several times, and calcined at 500℃ under nitrogen for 26 hours to obtain Ce-MOF. Ce-MOF, titanium tetra-n-butoxide and oxalic acid with a mass ratio of 1:3:1.4 g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare a nano-sized rare earth photocatalytic material Ce-MOF@TiO2; wherein the molar ratio of CeO2 to 4-isopropylbenzoic acid and ethylene carbonate is 1:1.4:1.5.

[0040] (2) Photothermal catalytic depolymerization and stripping: Ce-MOF@TiO2 obtained in step (1) and waste lithium-ion battery electrode materials are added to an isopropanol solution, and the temperature is adjusted after light irradiation, high temperature, low pressure and enhanced stirring to achieve PVDF depolymerization in the waste lithium-ion battery electrode materials, thereby obtaining high-value component monomers and fluorine-phosphorus mixed gas of energy material devices, and the high-value component monomers are returned to the energy device for regeneration; wherein, the mass ratio of Ce-MOF@TiO2, waste lithium-ion battery electrode materials and isopropanol is 1:10:29, the luminescence spectrum wavelength of the xenon lamp light source is 350nm, and the light intensity is 220mW / cm 2 , temperature is 140℃, nitrogen pressure is 0.29MPa, enhanced stirring speed is 385rpm, and reaction time is 13h.

[0041] (3) Acid leaching of lanthanum: The Ce-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is leached with 2.1M H3PO4 acid, and the stirring speed of the leaching is enhanced at 425 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0042] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can come from the Ce-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 20 mL / min, the temperature is 60°C, and the pH value is 5.5.

[0043] (5) Heating and solidifying phosphorus for purification: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 2 with 80% H₃PO₄ by mass, and the temperature is 90°C to obtain a lanthanum phosphate residue; the lanthanum phosphate residue is purified by alcohol washing and negative pressure heating and volatilization to obtain high-purity CePO₄, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The concentration of the purified ethanol washing is 85%, the holding temperature is 145°C, the vacuum pressure is 5 Pa, and the holding time is 6 hours.

[0044] Example 3

[0045] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0046] (1) Preparation of rare earth photocatalytic materials: Pr6O 11 , 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high-temperature reaction at 410°C for 8 hours. The solution after the high-temperature reaction was centrifuged at 3°C ​​at a speed of 600 rpm and then dried, washed with ethanol and water several times, and calcined at 420°C under nitrogen for 17 hours to obtain Pr-MOF; Pr-MOF, titanium tetra-n-butoxide and oxalic acid with a mass ratio of 1:3:0.6 g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material Pr-MOF@TiO2; among them, Pr6O 11 The molar ratio of 4-isopropylbenzoic acid to ethylene carbonate is 1:1.4:1.1.

[0047] (2) Photothermal catalytic depolymerization and stripping: Pr-MOF@TiO2 obtained in step (1) and waste lithium-ion battery electrode materials are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and intensified stirring to achieve PVDF depolymerization in the waste lithium-ion battery electrode materials, thereby obtaining high-value component monomers and fluorine-containing phosphorus mixed gas of energy material devices, and the high-value component monomers are returned to the energy device regeneration process; wherein the mass ratio of Pr-MOF@TiO2, waste lithium-ion battery electrode materials and isopropanol is 1:10:23.75, the luminescence spectrum wavelength of the xenon lamp light source is 310nm, and the light intensity is 220mW / cm 2 , temperature is 120℃, nitrogen pressure is 0.09MPa, enhanced stirring speed is 285rpm, and reaction time is 5h.

[0048] (3) Acid leaching of lanthanum: The Pr-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is leached with 0.5M H3PO4 acid, and the stirring speed of the leaching is enhanced at 325 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0049] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can come from the Pr-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 12 mL / min, the temperature is 40°C, and the pH value is 4.3.

[0050] (5) Heating and Purifying Phosphorus Fixation: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 1.2 with 76% H₃PO₄ by mass and heated to 82°C to obtain a lanthanum phosphate residue. The lanthanum phosphate residue is purified by alcohol washing and then heated under negative pressure for volatilization to obtain high-purity PrPO₄, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The concentration of the purified ethanol washing is 73%, the holding temperature is 125°C, the vacuum pressure is 2.6 Pa, and the holding time is 2 hours.

[0051] Example 4

[0052] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0053] (1) Preparation of rare earth photocatalytic materials: Nd2O3, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high-temperature reaction at 440℃ for 11 hours. The solution after the high-temperature reaction was centrifuged at 6℃ with a centrifugal speed of 900 rpm. It was then dried, washed with ethanol and water several times, and calcined at 480℃ under nitrogen for 24 hours to obtain Nd-MOF. Nd-MOF, titanium tetra-n-butoxide and oxalic acid with a mass ratio of 1:3:1.2 g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material Nd-MOF@TiO2; wherein the molar ratio of Nd2O3 to 4-isopropylbenzoic acid and ethylene carbonate is 1:1.4:1.4.

[0054] (2) Photothermal catalytic depolymerization and stripping: the Nd-MOF@TiO2 obtained in step (1) and the waste lithium-ion battery electrode material are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and enhanced stirring to achieve PVDF depolymerization in the waste lithium-ion battery electrode material, thereby obtaining high-value component monomers and fluorine-phosphorus mixed gas of energy material devices, and the high-value component monomers are returned to the energy device for regeneration; wherein the mass ratio of Nd-MOF@TiO2, waste lithium-ion battery electrode material and isopropanol is 1:10:27.95, the xenon lamp light source has a luminous spectrum wavelength of 340nm, and the light intensity is 200mW / cm 2, temperature is 135°C, nitrogen pressure is 0.25MPa, enhanced stirring speed is 360rpm, and reaction time is 11h.

[0055] (3) Acid leaching of lanthanum: The Nd-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is leached with 1.7M H3PO4, and the stirring speed of the leaching is enhanced at 400 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0056] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can be Nd-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 18 mL / min, the temperature is 55°C, and the pH value is 5.2.

[0057] (5) Heating and solidifying phosphorus for purification: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 1.8 with 79% H₃PO₄ by mass and heated to 88°C to obtain a lanthanum phosphate residue. The lanthanum phosphate residue is purified by alcohol washing and then heated under negative pressure for volatilization to obtain high-purity NdPO₄, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The purified ethanol washing concentration is 82%, the holding temperature is 140°C, the vacuum pressure is 4.4 Pa, and the holding time is 5 hours.

[0058] Example 5

[0059] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0060] (1) Preparation of rare earth photocatalytic materials: SmO, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high-temperature reaction at 420°C for 9 h. The solution after the high-temperature reaction was centrifuged at 4°C at a speed of 900 rpm, and then dried, washed with ethanol and water several times, and calcined at 440°C under nitrogen for 19 h to obtain Sm-MOF. Sm-MOF, titanium tetra-n-butoxide and oxalic acid in a mass ratio of 1:3:0.8 g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material Sm-MOF@TiO2; wherein the molar ratio of SmO to 4-isopropylbenzoic acid and ethylene carbonate is 1:1.4:1.2.

[0061] (2) Photothermal catalytic depolymerization and stripping: the Sm-MOF@TiO2 obtained in step (1) and the waste lithium-ion battery electrode material are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and intensified stirring to achieve PVDF depolymerization in the retired energy device, thereby obtaining high-value component monomers of the energy material device and a fluorine-phosphorus mixed gas, and the high-value component monomers are returned to the energy device for regeneration; wherein the mass ratio of Sm-MOF@TiO2, waste lithium-ion battery electrode material and isopropanol is 1:10:25.85, the xenon lamp light source has a luminous spectrum wavelength of 320nm, and a light intensity of 160mW / cm 2 , temperature is 125℃, nitrogen pressure is 0.17MPa, enhanced stirring speed is 310rpm, and reaction time is 7h.

[0062] (3) Acid leaching of lanthanum: The Sm-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is leached with 0.9M H3PO4 acid, and the stirring speed of the leaching is enhanced at 350 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0063] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can be the Sm-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 14 mL / min, the temperature is 45°C, and the pH value is 5.2.

[0064] (5) Heating and solidifying phosphorus for purification: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 1.4 with 77% H₃PO₄ by mass, and the temperature is 84°C to obtain a lanthanum phosphate slag; the lanthanum phosphate slag is purified by alcohol washing and negative pressure heating and volatilization to obtain high-purity Sm₃(PO₄)₂, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The purified ethanol washing concentration is 76%, the holding temperature is 130°C, the vacuum pressure is 3.2 Pa, and the holding time is 3 hours.

[0065] Example 6

[0066] A method for catalytic stripping and high-value utilization of organic matter from retired energy devices comprises the following steps:

[0067] (1) Preparation of rare earth photocatalytic materials: Eu2O3, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor and subjected to a high temperature reaction at 430℃ for 10 hours. The solution after the high temperature reaction was centrifuged at 5℃ with a centrifugal speed of 800 rpm, and then dried, washed with ethanol and water for multiple times, and calcined at 460℃ under nitrogen for 21 hours to obtain Eu-MOF; Eu-MOF, titanium tetra-n-butoxide and oxalic acid with a mass ratio of 1:3:1 g / g were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material Eu-MOF@TiO2; wherein the molar ratio of Eu2O3 to 4-isopropylbenzoic acid and ethylene carbonate is 1:1.4:1.3.

[0068] (2) Photothermal catalytic depolymerization and stripping: the Eu-MOF@TiO2 obtained in step (1) and the waste lithium-ion battery electrode material are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and enhanced stirring to achieve PVDF depolymerization in the retired energy device, thereby obtaining high-value component monomers of the energy material device and a fluorine-phosphorus mixed gas, and the high-value component monomers are returned to the energy device for regeneration; wherein the mass ratio of Eu-MOF@TiO2, waste lithium-ion battery electrode material and isopropanol is 1:10:26.9, the xenon lamp light source has a luminous spectrum wavelength of 330nm, and a light intensity of 180mW / cm 2 , temperature is 130℃, nitrogen pressure is 0.21MPa, enhanced stirring speed is 335rpm, and reaction time is 9h.

[0069] (3) Acid leaching of lanthanum: The Eu-MOF@TiO2 with low catalytic efficiency after the number of cycles in step (2) is acid-leached with 1.3M H3PO4, and the stirring speed of the leaching is enhanced at 375 rpm. Lanthanum-rich leachate and titanium-rich slag are obtained, and the titanium-rich slag is returned to the electroplating solution production process;

[0070] (4) Low-temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leachate obtained in step (3) at a certain flow rate and subjected to microwave mechanical stirring to obtain a mixed gas of fluorine-containing lanthanum slag, defluorination residual liquid, H2, CH4 and C2H6; the spent rare earth photocatalyst can come from the Eu-MOF@TiO2 that has reached the number of cycles in step (2); wherein the flow rate of the fluorine-containing phosphorus mixed gas is 16 mL / min, the temperature is 50°C, and the pH value is 4.9.

[0071] (5) Heating and solidifying phosphorus for purification: The defluorinated residual solution obtained in step (4) is adjusted to a pH of 1.6 with 78% H₃PO₄ by mass, and the temperature is 86°C to obtain a phosphorus lanthanum slag; the phosphorus lanthanum slag is purified by alcohol washing and negative pressure heating and volatilization to obtain high-purity EuPO₄, which can be directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse. The purified ethanol washing concentration is 79%, the holding temperature is 135°C, the vacuum pressure is 3.8 Pa, and the holding time is 4 hours.

[0072] Comparative Example 1

[0073] A method for catalytic separation and high-value utilization of fluorine-containing binders in retired energy devices, referring to Example 2, except that the photothermal catalytic depolymerization and stripping process does not use heating but only uses light, without heating. The rest of the process and parameters are the same as Example 2.

[0074] Since the photothermal catalytic depolymerization and stripping process in Comparative Example 1 was not heated, the toxic elements fluorine and phosphorus in the binder were not completely vaporized and attached to the surface of the high-value component monomers in large quantities, resulting in additional impurity removal processes in each link, and the diffusion ability between groups was weakened, resulting in a very low stripping rate and increased cost, and the purpose of high value was not achieved.

[0075] Comparative Example 2

[0076] A method for catalytic separation and high-value utilization of fluorine-containing binders in retired energy devices, referring to Example 2, except that the photothermal catalytic depolymerization and stripping process only involves heating without light exposure, and the remaining processes and parameters are the same as those in Example 2.

[0077] Since no photocatalytic reaction occurs in Example 2, the hydroxyl group cannot attack and replace the fluorine atoms, resulting in difficulty in PVDF depolymerization and a very low stripping rate. Only the unstable PVDF is denatured and fails due to heat, and the toxic fluorine element is not converted into a directional product, resulting in difficulty in defluorination, and the effective stripping of retired energy device components and the efficient recovery of high-value components cannot be achieved.

[0078] The organic binder stripping rates and residual amounts of impurity elements in Examples 1 to 6 and Comparative Examples 1 to 2 are shown in Table 1:

[0079] Table 1

[0080] The description of the above embodiments is only used to help understand the technical solution and core ideas of the present invention. It should be pointed out that for those skilled in the art, several improvements and modifications can be made to the present invention without departing from the principles of the present invention. These improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for catalytic separation and high-value utilization of fluorinated organic binders in retired new energy devices, characterized in that: The method comprises the following steps: (1) Preparation of rare earth photocatalytic materials: lanthanide metal oxide, 4-isopropylbenzoic acid and ethylene carbonate were placed in a microwave reactor for high temperature reaction at 400°C to 450°C for 7 to 12 hours. The molar ratio of lanthanide metal oxide, 4-isopropylbenzoic acid and ethylene carbonate was 1:1.4:1 to 1.

5. The solution after high temperature reaction was centrifuged at 2°C to 7°C, dried, washed with ethanol and water for multiple times, and then calcined at 400 to 500°C under nitrogen for 15 to 26 hours to obtain a MOF catalyst carrier, named R-MOF, where R represents the type of lanthanide metal, selected from one of La, Ce, Pr, Nd, Sm and Eu. R-MOF, titanium tetra-n-butoxide and oxalic acid were added to deionized water and transferred to a rotary evaporator, and the vacuum degree was maintained at 10 -4 ~10 -5 mbar, until the water evaporates and dries to prepare the nano-sized rare earth photocatalytic material R-MOF@TiO2; the mass ratio of R--MOF, titanium tetra-n-butoxide and oxalic acid is 1:3:0.4-1.4g / g; (2) Photothermal catalytic depolymerization and stripping: The R-MOF@TiO2 obtained in step (1) and the retired new energy device are added to an isopropanol solution, and the temperature is adjusted after light exposure, high temperature, low pressure and enhanced stirring to achieve depolymerization of the fluorine-containing organic binder in the retired new energy device to obtain high-value component monomers of the energy material device and fluorine-containing phosphorus mixed gas; the light exposure, high temperature, low pressure and enhanced stirring, the xenon lamp light source has a luminous spectrum wavelength range of 300nm to 350nm, and a light intensity range of 120mW / cm 2 ~220mW / cm 2 , the temperature is 110-140°C, the nitrogen pressure is 0.05MPa-0.29MPa, the intensive stirring speed is 260rpm-385rpm, and the stirring time is 3h-13h; (3) Acid leaching of lanthanum: The R-MOF@TiO2 with low catalytic efficiency obtained in step (2) is acid-leached for multiple cycles to obtain a lanthanum-rich leachate and titanium-rich slag; (4) low temperature fluorine precipitation: the fluorine-containing phosphorus mixed gas obtained in step (2) is introduced into the lanthanum-rich leaching solution obtained in step (3) at a certain flow rate for microwave mechanical stirring to obtain fluorine-containing lanthanum slag, defluorination residual liquid and mixed gas, wherein the mixed gas contains H2, CH4 and C2H6; (5) Heating and purifying phosphorus fixation: The defluorinated residual liquid obtained in step (4) is adjusted to a pH value of 1 to 2 using 75 to 80% by mass of H3PO4, and the temperature is raised to 80°C to 90°C to obtain phosphorus lanthanum slag. The phosphorus lanthanum slag is purified by alcohol washing and negative pressure heating volatilization to obtain high-purity RPO4 which is directly used in the production of fluorescent materials. The water vapor is condensed and returned to step (2) for reuse.

2. The method according to claim 1, characterized in that The retired new energy device is one of waste lithium-ion battery electrode materials, waste circuit boards and waste photovoltaic panels.

3. The method according to claim 1, characterized in that The fluorine-containing organic binder is one of polyvinylidene fluoride, polytetrafluoroethylene, fluorine-containing styrene-butadiene rubber and fluorine-containing carboxymethyl cellulose.

4. The method according to claim 1, characterized in that: The rotation speed of the low-temperature centrifugation in step (1) is 500 to 1000 rpm.

5. The method according to claim 1, characterized in that The mass ratio of R-MOF@TiO2, retired new energy devices and isopropanol described in step (2) is 1:10:22.7-29.

6. The method according to claim 1, characterized in that The acid in step (3) is 0.1M to 2.1M H3PO4, and the stirring speed of the enhanced leaching is 300rpm to 425rpm.

7. The method according to claim 1, characterized in that The flow rate of the fluorine-phosphorus mixed gas in step (4) is 10 mL / min to 20 mL / min, the temperature is 35 to 60° C., and the pH value ranges from 4 to 5.

8.

8. The method according to claim 1, characterized in that The alcohol washing in step (5) is performed with ethanol having a mass concentration of 70% to 85%, the insulation temperature is 120° C. to 145° C., the vacuum pressure is 2 to 5 Pa, and the insulation time is 1 h to 6 h.

9. The method according to claim 1, characterized in that: The high-value component monomers obtained in step (2) are returned to the energy device regeneration process; and the titanium-rich slag obtained in step (3) is returned to the electroplating solution production process.

Images