CN115873301A - Method for recycling carbon fibers by treating carbon fiber composite material through microwave molten salt concerted catalysis - Google Patents
Method for recycling carbon fibers by treating carbon fiber composite material through microwave molten salt concerted catalysis Download PDFInfo
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02W—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO WASTEWATER TREATMENT OR WASTE MANAGEMENT
- Y02W30/00—Technologies for solid waste management
- Y02W30/50—Reuse, recycling or recovery technologies
- Y02W30/62—Plastics recycling; Rubber recycling
Abstract
The invention discloses a method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis, and belongs to the technical field of carbon fiber composite materials. The method specifically comprises the following steps: and mixing the waste carbon fiber composite material with a molten salt catalyst, heating by microwave, and cooling to obtain a solid product, namely the recovered carbon fiber. The method can effectively improve the recovery rate of the carbon fiber, avoid the great reduction of various properties of the carbon fiber, reduce the treatment cost, has simple operation process, realizes the purposes of resource saving and environmental protection, and is suitable for industrial production.
Description
Technical Field
The invention belongs to the technical field of carbon fiber composite materials, and particularly relates to a method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis.
Background
The carbon fiber reinforced resin matrix composite material has excellent properties such as high specific strength, high specific modulus, heat resistance, corrosion resistance and the like, so that the carbon fiber reinforced resin matrix composite material is widely applied to the fields of aerospace, wind power generation, sports and leisure, buildings, transportation and the like. With the increase of the demand of the carbon fiber composite material, the waste of the carbon fiber composite material is increased, which causes problems of environmental pollution, resource waste and the like. Therefore, the efficient recovery of waste carbon fibers is of great significance to the development of carbon materials.
In the prior art, the main recovery methods of carbon fiber composite materials include mechanical methods, chemical methods and pyrolysis methods. Among them, the mechanical method is to treat the carbon fiber reinforced resin composite material as incombustible solid waste by cutting into powder or granules as a filler, a paving material, or the like, or even by landfill. However, the carbon fiber reinforced resin composite material contains high-value carbon fibers, and the treatment method undoubtedly causes great waste of carbon fiber resources. For example, palmer et al [ Successful closed-loop recycling of thermal compositions. Applied Science and Manufacturing,2009;40:490-49] after mechanical treatment of the waste composite material, the recycled material is cut into particles or powder for use as a filler, resulting in waste of high-value carbon fiber resources contained in the carbon fiber reinforced resin composite material.
The chemical method degrades the crosslinked resin component through chemical reaction, and then dissolves the degraded micromolecules in the solvent, thereby realizing the purpose of recycling the carbon fiber from the carbon fiber reinforced resin composite material. However, the method uses a large amount of solvent in the chemical recovery process, and is very easy to pollute the environment; in addition, the solvent separation (liquid separation, extraction, distillation, etc.) after use is complicated in operation, resulting in high recovery cost. For example, jiang et al [ On the scientific chemical recycling of carbon fiber oxides under the mill conditions. Compositions Science and Technology,2017, 151:243-251] using sulfuric acid or nitric acid to pretreat the waste composite material, and realizing the recovery of carbon fiber in the carbon fiber composite material in KOH and polyethanol solution. However, a large amount of sulfuric acid or nitric acid and a polyvinyl alcohol solution are used in the recovery process, which causes environmental pollution, and the recovery process is more complicated, increasing the recovery cost.
The pyrolysis method is a method for performing high-temperature thermal decomposition on the waste carbon fiber reinforced resin composite material in an inert gas or air atmosphere by utilizing the high-temperature resistance characteristic of the reinforced fiber. The pyrolysis process is simple to operate and is the most common method for recovering carbon fibers at present, but a large amount of pyrolysis carbon is easily formed on the surface of the recovered carbon fibers or is excessively oxidized due to overhigh temperature, and the performance of the carbon fibers is greatly reduced. This will affect the subsequent processing and processing recycling properties of the recycled carbon fibers. For example, yang et al [ Recycling of carbon fiber in formed epoxy resin compositions in combination with variaus epoxy resins in nitrogen-epoxy resins in molybdenum ethers. Journal of Analytical and Applied Pyrolysis,2015, 112:253-26 the effect of temperature on the properties of recycled carbon fibres was explored by exposure to air. However, the reaction temperature is too high, so that the surface portion of the carbon fiber is oxidized.
In summary, how to simply, environmentally and efficiently recover carbon fibers from waste carbon fiber composite materials is a technical problem that needs to be solved by those skilled in the art.
Disclosure of Invention
In order to solve the problems in the prior art, the invention provides a method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt and concerted catalysis.
In order to achieve the purpose, the invention provides the following technical scheme:
the invention provides a method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis, which comprises the following steps:
and mixing the waste carbon fiber composite material with a molten salt catalyst, heating by microwave, and cooling to obtain a solid product, namely the recovered carbon fiber.
Has the advantages that: the invention utilizes the characteristic of selective heating of the waste carbon fiber composite material by microwaves to uniformly heat the whole carbon fiber resin matrix composite material, thereby greatly shortening the treatment time and improving the recovery efficiency and effect of carbon fibers.
Further, the amount of the molten salt catalyst is 0.1-0.5 g-cm -2 The mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 2-4.
Further, the waste carbon fiber composite material includes a matrix resin and carbon fibers.
Furthermore, the matrix resin comprises one or more of epoxy resin, unsaturated polyester, phenolic resin and vinyl resin; the carbon fibers include one or both of PAN-based carbon fibers or pitch-based carbon fibers.
Further, the molten salt catalyst comprises the following raw materials in percentage by mass: 80-100% of zinc chloride and 0-20% of potassium chloride.
Has the beneficial effects that: according to the invention, zinc chloride and potassium chloride are added as molten salt catalysts, and when the reaction reaches a certain temperature, the molten salt catalysts are changed into molten liquid films which are attached to the surface of the carbon fiber and permeate into a material system, wherein the zinc chloride plays a main catalytic role in the pyrolysis process and can effectively reduce the temperature and time of resin pyrolysis, and the potassium chloride is mainly added to form eutectic salt with the zinc chloride so as to reach a lower melting point.
Further, the microwave heating is as follows: heating to 300-500 deg.C with microwave, and keeping the temperature for 10-60min; the frequency of the microwave heating is 865-965MHz or 2400-2500MHz; 4-10LPM air is required to be introduced during microwave heating.
Has the advantages that: the method is characterized in that air is introduced under normal pressure, a certain temperature is controlled, the resin in the waste carbon fiber composite material is subjected to oxidation reaction, and the carbon fiber is not subjected to reaction, so that organic matters in the resin are removed, and the carbon fiber with a smooth surface and basically no residual resin is obtained.
Further, the solid product needs to be ultrasonically cleaned in water for 10-30min and then dried at a temperature of 60 ℃ for 60-100min.
Further, the waste carbon fiber composite material can be of a plate structure and can also be a special-shaped piece.
Compared with the prior art, the invention has the following beneficial effects:
the invention provides a method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis. The degraded carbon fiber is subjected to ultrasonic cleaning in water to obtain clean carbon fiber which is not oxidized, so that the recycled carbon fiber has small reduction degree of mechanical property and high retention rate of tensile strength of the monofilament.
In addition, the invention ensures that the length and the diameter of the carbon fiber are basically not burnt while the resin organic matter is burnt, the obtained recycled carbon fiber has smooth surface, no obvious defect and no resin residue, and can be compounded with the matrix again to form a new carbon fiber reinforced composite material. The method has simple operation process, can effectively improve the recovery rate of the carbon fiber and reduce the treatment cost, is an environment-friendly recovery method, and is suitable for industrial production.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings needed in the embodiments will be briefly described below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art to obtain other drawings without creative efforts.
FIG. 1 is a pictorial representation of a carbon fiber resin-based reinforced composite of example 1 prior to processing;
FIG. 2 is a physical representation of the carbon fiber obtained after the carbon fiber resin-based reinforced composite material of example 1 is treated;
FIG. 3 is a scanning electron microscope image of carbon fibers obtained after the carbon fiber resin-based reinforced composite material in example 1 is treated.
Detailed Description
Reference will now be made in detail to various exemplary embodiments of the invention, the detailed description should not be construed as limiting the invention but rather as a more detailed description of certain aspects, features and embodiments of the invention. It is to be understood that the terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.
Further, for numerical ranges in this disclosure, it is understood that each intervening value, between the upper and lower limit of that range, is also specifically disclosed. Every smaller range between any stated value or intervening value in a stated range and any other stated or intervening value in a stated range is encompassed within the invention. The upper and lower limits of these smaller ranges may independently be included or excluded in the range.
Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein can be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated herein by reference to disclose and describe the methods and/or materials in connection with which the documents are cited. In case of conflict with any incorporated document, the present specification will control.
It will be apparent to those skilled in the art that various modifications and variations can be made in the specific embodiments of the present disclosure without departing from the scope or spirit of the disclosure. Other embodiments will be apparent to those skilled in the art from consideration of the specification. The description and examples are intended to be illustrative only.
As used herein, the terms "comprising," "including," "having," "containing," and the like are open-ended terms that mean including, but not limited to.
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
mixing the waste carbon fiber composite material with a molten salt catalyst, heating to 300-500 ℃ by microwave at the frequency of 865-965MHz or 2400-2500MHz, then preserving heat for 10-60min, introducing 4-10LPM air during microwave heating, naturally cooling to room temperature, taking out a solid product, ultrasonically cleaning for 10-30min by using water, and then drying for 60-100min at the temperature of 60 ℃ to obtain the recycled carbon fiber.
Preferably, the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1 to (2-4), and the dosage of the molten salt catalyst is 0.1-0.5 g-cm -2 。
Preferably, the waste carbon fiber composite material includes a matrix resin and carbon fibers; the matrix resin comprises one or more of epoxy resin, unsaturated polyester, phenolic resin and vinyl resin; the carbon fibers include one or both of PAN-based carbon fibers or pitch-based carbon fibers.
Preferably, the molten salt catalyst comprises the following raw materials in parts by mass: 80-100% of zinc chloride and 0-20% of potassium chloride.
The room temperature in the present invention means 25. + -. 2 ℃.
The starting materials described in the present invention are all commercially available.
In the waste carbon fiber composite material in the embodiment of the invention, the content of matrix resin is 23%, and the content of carbon fiber is 67%.
Example 1
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material (figure 1) with matrix resin of epoxy resin into size of 50mm × 20mm × 3mm, placing into square crucible, and uniformly spreading 0.1g cm on its surface -2 The molten salt catalyst of (2), wherein the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 3, and the mass ratio of each component in the molten salt catalyst is as follows: 90% zinc chloride and 10% potassium chloride.
(2) Putting the square crucible into a microwave heating device, introducing 6LPM air, heating to 400 ℃ at a frequency of 2450MHz, preserving heat for 30min to enable resin organic matters to generate a pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 30min, and drying at a temperature of 60 ℃ for 80min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue, and the real image and the scanning electron microscope image of the recycled carbon fiber are shown in the figure 2 and the figure 3 respectively. The recovered carbon fiber was subjected to a monofilament tensile test by a universal testing machine according to ASTM-D3379, and the retention of tensile strength of the monofilament was 93.81%.
Example 2
A method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with unsaturated polyester as matrix resin into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.2g cm on the surface -2 The molten salt catalyst of (2), wherein the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 3, and the mass ratio of each component in the molten salt catalyst is as follows: 80% zinc chloride and 20% potassium chloride.
(2) Putting the square crucible into a microwave heating device, introducing 4LPM air, heating to 450 ℃ at a frequency of 2450MHz, preserving heat for 20min to enable resin organic matters to generate a pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 30min, and drying at 60 ℃ for 60min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fiber was subjected to a monofilament tensile test by a universal testing machine according to ASTM-D3379, and the retention of tensile strength of the monofilament was 93.21%.
Example 3
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with matrix resin of vinyl resin into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.3g cm on the surface -2 The molten salt catalyst of (1), wherein the carbon fiber is discardedThe mass ratio of the composite material to the molten salt catalyst is 1:2, and the mass ratio of the components in the molten salt catalyst is as follows: 90% zinc chloride and 10% potassium chloride.
(2) Putting the square crucible into a microwave heating device, introducing 8LPM air, heating to 400 ℃ at a frequency of 2450MHz, preserving heat for 20min to enable resin organic matters to generate a pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 20min, and drying at a temperature of 60 ℃ for 70min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fiber was subjected to a monofilament tensile test by a universal testing machine according to ASTM-D3379, and the retention of tensile strength of the monofilament was 91.62%.
Example 4
A method for recovering carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with matrix resin of phenolic resin into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.2g cm on the surface -2 The molten salt catalyst of (2), wherein the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1:2, and the mass ratio of each component in the molten salt catalyst is as follows: 80% zinc chloride and 20% potassium chloride.
(2) And (2) putting the square crucible into a microwave heating device, introducing 8LPM air, heating to 400 ℃ at the frequency of 915MHz, preserving the temperature for 50min to ensure that resin organic matters are subjected to pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 20min, and drying at the temperature of 60 ℃ for 70min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fibers were subjected to a monofilament tensile test using a universal tester according to ASTM-D3379, and the monofilament tensile strength retention rate was 91.81%.
Example 5
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with matrix resin of epoxy resin and vinyl resin into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.3g cm on the surface -2 The molten salt catalyst of (2), wherein the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 4, and the mass ratio of each component in the molten salt catalyst is as follows: 80% zinc chloride and 20% potassium chloride.
(2) Putting the square crucible into a microwave heating device, introducing 8LPM air, heating to 500 ℃ at the frequency of 915MHz, preserving the temperature for 15min to ensure that resin organic matters are subjected to pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 10min, and drying at the temperature of 60 ℃ for 100min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fibers were subjected to a monofilament tensile test using a universal tester according to ASTM-D3379, and the monofilament tensile strength retention rate was 92.75%.
Example 6
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with matrix resin of epoxy resin, unsaturated polyester and phenolic resin into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.2g cm on the surface -2 The molten salt catalyst of (2), wherein the mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 4, and the mass ratio of each component in the molten salt catalyst is as follows: 80% zinc chloride and 20% potassium chloride.
(2) Putting the square crucible into a microwave heating device, introducing 10LPM air, heating to 350 ℃ at a frequency of 2450MHz, preserving heat for 40min to enable resin organic matters to generate a pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 10min, and drying at a temperature of 60 ℃ for 80min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fibers were subjected to a monofilament tensile test by a universal testing machine according to ASTM-D3379, and the retention of tensile strength of the monofilament was 92.38%.
Example 7
A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis comprises the following steps:
(1) Cutting waste carbon fiber composite material with epoxy resin as matrix into size of 50mm × 20mm × 3mm, placing into a square crucible, and uniformly spreading 0.1g cm on the surface -2 The molten salt catalyst zinc chloride is prepared by mixing the waste carbon fiber composite material and the molten salt catalyst zinc chloride in a mass ratio of 1: 3.
(2) Putting the square crucible into a microwave heating device, introducing 6LPM air, heating to 400 ℃ at a frequency of 2450MHz, preserving heat for 30min to enable resin organic matters to generate a pyrolysis reaction, naturally cooling to room temperature after heating is stopped, taking out a solid product, ultrasonically cleaning the solid product in water for 30min, and drying at a temperature of 60 ℃ for 80min to obtain the recovered carbon fibers.
The obtained recycled carbon fiber has smooth and complete surface and no resin residue. The recovered carbon fibers were subjected to a monofilament tensile test using a universal testing machine according to ASTM-D3379, and the monofilament tensile strength retention ratio was 91.91%.
Comparative example 1
The method for recovering the carbon fibers from the carbon fiber composite material through microwave molten salt concerted catalytic treatment is only different from the method in example 1 in that the mass ratio of each component in the molten salt catalyst is as follows: 50% zinc chloride and 50% potassium chloride, and the rest of the process steps and parameters are the same as those of example 1. The surface of the obtained recycled carbon fiber still has 1-5 percent of resin residues, and the recycled carbon fiber is subjected to monofilament tensile test by using a universal testing machine according to the ASTM-D3379 standard, so that the monofilament tensile strength retention rate is 88.21 percent.
Comparative example 2
The method for recovering carbon fibers from a carbon fiber composite material through microwave molten salt concerted catalytic treatment is different from the method in the embodiment 1 only in that all molten salt catalysts are potassium chloride, and the rest process steps and parameters are the same as those in the embodiment 1. The surface of the obtained recycled carbon fiber still has 1-5% of resin residue, and the recycled carbon fiber is subjected to monofilament tensile test by using a universal testing machine according to the ASTM-D3379 standard, so that the monofilament tensile strength retention rate is 87.54%.
Comparative example 3
The method for recycling the carbon fibers from the carbon fiber composite material through microwave molten salt concerted catalytic treatment only differs from the embodiment 1 in that a molten salt catalyst is aluminum chloride, and the rest process steps and parameters are the same as those in the embodiment 1. The surface of the obtained recycled carbon fiber still has 1-5% of resin residues, and the recycled carbon fiber is subjected to monofilament tensile test by using a universal testing machine according to the ASTM-D3379 standard, so that the monofilament tensile strength retention rate is 87.91%.
Comparative example 4
The method for recovering the carbon fibers from the carbon fiber composite material through microwave molten salt concerted catalytic treatment only differs from the embodiment 1 in that a common catalyst potassium hydroxide is adopted, and the rest process steps and parameters are the same as those in the embodiment 1. The surface of the obtained recycled carbon fiber still has 1-5% of resin residues, and the recycled carbon fiber is subjected to monofilament tensile test by using a universal testing machine according to the ASTM-D3379 standard, so that the monofilament tensile strength retention rate is 85.49%.
Comparative example 5
A method for recycling carbon fibers from a carbon fiber composite material through microwave molten salt concerted catalytic treatment, which comprises the same steps as in example 1 in step (1).
(2) Heating the square crucible at 400 ℃ for 30min by adopting a direct heating method to carry out pyrolysis reaction on resin organic matters, naturally cooling to room temperature after stopping heating, taking out a solid product, ultrasonically cleaning the solid product in water for 30min, and drying the solid product at 60 ℃ for 60min to obtain the recovered carbon fibers. The surface of the obtained recycled carbon fiber still has 1-5% of resin residues, and the recycled carbon fiber is subjected to monofilament tensile test by using a universal testing machine according to the ASTM-D3379 standard, so that the monofilament tensile strength retention rate is 86.87%.
The above description is only for the preferred embodiment of the present invention, and the protection scope of the present invention is not limited thereto, and any person skilled in the art should be able to cover the technical scope of the present invention, the technical solution and the inventive concept of the present invention equivalent or change within the technical scope of the present invention.
Claims (8)
1. A method for recycling carbon fibers by treating a carbon fiber composite material through microwave molten salt concerted catalysis is characterized by comprising the following steps:
and mixing the waste carbon fiber composite material with a molten salt catalyst, heating by microwave, and cooling to obtain a solid product, namely the recovered carbon fiber.
2. The method for recovering carbon fibers from carbon fiber composite material through microwave molten salt concerted catalysis treatment according to claim 1, wherein the amount of the molten salt catalyst is 0.1-0.5 g-cm -2 The mass ratio of the waste carbon fiber composite material to the molten salt catalyst is 1: 2-4.
3. The method for recovering carbon fibers from a carbon fiber composite material through microwave molten salt concerted catalytic treatment according to claim 1, wherein the waste carbon fiber composite material comprises a matrix resin and carbon fibers.
4. The method for recycling the carbon fibers from the carbon fiber composite material through the microwave molten salt concerted catalysis treatment according to claim 3, wherein the matrix resin comprises one or more of epoxy resin, unsaturated polyester, phenolic resin and vinyl resin;
the carbon fibers include one or both of PAN-based carbon fibers or pitch-based carbon fibers.
5. The method for recovering carbon fibers from carbon fiber composite material through microwave molten salt concerted catalytic treatment is characterized in that the molten salt catalyst comprises the following raw materials in parts by mass: 80-100% of zinc chloride and 0-20% of potassium chloride.
6. The method for recycling carbon fibers from carbon fiber composite material through microwave molten salt concerted catalytic treatment according to claim 1, wherein the microwave heating is as follows: heating to 300-500 deg.C with microwave, and keeping the temperature for 10-60min.
7. The method for recycling carbon fibers through microwave molten salt co-catalytic treatment of carbon fiber composite material according to claim 6, wherein the frequency of microwave heating is 865-965MHz or 2400-2500MHz.
8. The method for recovering carbon fibers from carbon fiber composite materials through microwave molten salt concerted catalytic treatment according to claim 7, wherein air with the pressure of 4-10LPM is introduced during microwave heating.
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