Separation method of polyester-cotton textile

Abstract

The application provides a polyester-cotton textile fabric separation method, the polyester-cotton textile fabric includes polyester and cotton fibers, and the separation method comprises the following steps: S1, performing shearing treatment on the polyester-cotton textile fabric to obtain rags; S2, performing opening treatment on the rags to obtain bundle-shaped fibers; S3, dispersing the bundle-shaped fibers in a gas floatation precipitation solution, continuously introducing gas at the bottom of the gas floatation precipitation solution to form rising bubbles, part of the bundle-shaped fibers is adhered to the bubbles and floats to the liquid surface to form a floating fiber component, and the other part sinks to the bottom of the gas floatation precipitation solution to form a sinking fiber component; S4, dispersing the sinking fiber component in the gas floatation precipitation solution and performing gas floatation precipitation treatment; and S5, repeating step S4 for 2-3 times. The application separates polyester fibers and cotton fibers by using the physical and chemical property differences of the two fibers by a physical method, and the original characteristics of the fibers are maximally retained, and the demand for subsequent high-value utilization of the fibers is ensured.

Description

Technical Field

[0001] This application relates to the field of waste polyester-cotton textile recycling technology, and in particular to a method for separating polyester-cotton textiles. Background Technology

[0002] With the development of the textile industry and the continuous improvement of people's living standards, a large amount of waste textiles are generated every year, especially waste polyester-cotton textiles. Polyester is composed of polyethylene terephthalate (PET), which degrades extremely slowly in nature. Cotton fiber is a natural cellulose fiber with excellent properties and is widely used as a raw material in various industries, possessing high utilization value. However, due to the difficulty of recycling, waste polyester-cotton textiles are mostly not effectively recycled and are instead landfilled or incinerated as waste. This not only causes serious resource waste but also leads to environmental pollution problems.

[0003] Traditional methods for separating polyester-cotton textiles mainly fall into two categories: chemical methods and enzymatic methods. Common chemical methods include acid-base hydrolysis, alcoholysis, and hydrothermal methods. Chemical methods typically involve reacting a specific fiber in the polyester-cotton fabric with a particular chemical agent, breaking it down into smaller molecules that are then eluted to achieve separation and recovery. The other category is enzymatic methods. These methods utilize the singular and efficient catalysis of enzymes on cotton fibers, accelerating the hydrolysis of cellulose to achieve polyester-cotton separation.

[0004] It can be seen that traditional separation methods all involve decomposing or dissolving one component in the polyester-cotton fiber to achieve the purpose of separation. However, this method will damage the original properties of the fiber, increase the difficulty of fiber resource utilization, reduce its resource utilization value, and pose a significant risk of environmental pollution. Summary of the Invention

[0005] Therefore, it is necessary to provide a method for separating polyester and cotton textiles that can efficiently separate the two fibers, retain as much of the recyclable components as possible for high-value utilization, and reduce environmental pollution.

[0006] This application provides a method for separating polyester-cotton textiles, which include polyester and cotton fibers, comprising the following steps:

[0007] S1. Cutting: Cutting polyester-cotton textiles to obtain scraps of fabric.

[0008] S2, Opening: The scraps of fabric are opened to obtain bundled fibers;

[0009] S3, Air flotation sedimentation: Bundle fibers are dispersed in an air flotation sedimentation solution. Gas is continuously introduced into the bottom of the air flotation sedimentation solution to form rising bubbles. Part of the bundle fibers adheres to the bubbles and floats to the liquid surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0010] S4. Disperse the sinking fiber components in the air flotation sedimentation solution and perform air flotation sedimentation treatment;

[0011] S5. Repeat step S4 2 to 3 times;

[0012] The air flotation sedimentation solution includes a surfactant and a metal salt. The surfactant includes at least one of methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate. The metal salt includes at least one of calcium chloride, calcium sulfate, and sodium chloride.

[0013] In some embodiments, the length of the bundled fibers is 1 mm to 5 mm.

[0014] In some embodiments, the mass concentration of the surfactant is 0.05% to 0.5%.

[0015] In some embodiments, the mass concentration of the metal salt is 10% to 40%.

[0016] In some embodiments, a gas distributor is used to introduce gas into the bottom of the flotation sedimentation solution, causing the gas to form bubbles that fill the flotation sedimentation solution from bottom to top.

[0017] In some embodiments, the flow rate of the introduced gas is 0.05 L / min to 0.5 L / min.

[0018] In some implementations, the number of gas distributors is one or more.

[0019] In some embodiments, the gas introduced into the bottom of the flotation sedimentation solution is air or oxygen.

[0020] In some embodiments, the solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 0.5 g / L to 5 g / L.

[0021] In some embodiments, the following steps are included before the cutting process: cleaning and disinfecting the polyester-cotton fabric.

[0022] In some embodiments, after step S3, the following step is also included: removing the floating fiber components using a scraper or scraping net.

[0023] This application utilizes the differences in the physicochemical properties of polyester and cotton fibers and employs mechanical and physical methods such as shearing and opening to separate the two fibers. This maximizes the preservation of the original characteristics of the fibers, ensures the demand for high-value utilization of the fibers, and at the same time reduces environmental pollution and production costs.

[0024] This application utilizes the differences in physicochemical properties between different textile fiber components to achieve separation by means of surfactants or chemical modification. This separation method is highly adaptable to the separation process of polyester-cotton textiles with different component ratios. Attached Figure Description

[0025] To more clearly illustrate the technical solutions in the embodiments of this application, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the accompanying drawings described below are only some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0026] Figure 1 This is a schematic flowchart of a method for separating polyester-cotton textiles according to an embodiment of this application;

[0027] Figure 2 This is a schematic diagram of bundled fibers dispersed in an air flotation sedimentation solution in one embodiment of this application. Detailed Implementation

[0028] To facilitate understanding of this application, a more complete description will be provided below with reference to the accompanying drawings. Preferred embodiments of this application are shown in the drawings. However, this application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of this application.

[0029] Unless otherwise defined, 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 application belongs. The terminology used herein is for the purpose of describing particular embodiments only and is not intended to be limiting of the application.

[0030] As used herein, the term "and / or" includes any and all combinations of one or more of the related listed items.

[0031] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0032] In this application, numerical ranges are referred to as continuous unless otherwise specified, and include the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be merged. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0033] In this article, when referring to units for data ranges, if the unit is only followed by the right endpoint, it indicates that the units for the left and right endpoints are the same. For example, 15–25 mm means that the units for the left endpoint “15” and the right endpoint “25” are both mm (millimeters).

[0034] Furthermore, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of indicated technical features. Thus, a feature defined as "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of the invention, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified. In the description of this application, "several" means at least one, such as one, two, etc., unless otherwise explicitly specified.

[0035] In this application, "bundled fibers" refers to a state in which a large number of fibers are mixed together, but each fiber is an independent strip.

[0036] Traditional methods for separating polyester-cotton textiles mainly fall into two categories: chemical methods and chemical methods. Chemical methods involve reacting a specific fiber in the polyester-cotton fabric with a particular chemical agent, decomposing it into smaller molecules that are then washed away to achieve separation and recycling. However, these methods have the following drawbacks: ① They require large quantities of chemical agents. Some of these agents are highly corrosive or volatile, leading to environmental pollution. ② The chemical reaction conditions are stringent. The treatment effect is related to multiple factors such as solution concentration, temperature, pressure, and reaction time, resulting in a long process flow and complex process control. ③ The chemical decomposition products are complex. Neither polyester nor cotton fibers produce simple, single-component small-molecule substances as decomposition products, and the added chemical agents are prone to residue, increasing the difficulty of subsequent high-value utilization. ④ They have poor adaptability. In actual recycling, the polyester-cotton ratio is random after collection and mixing of waste textiles, making it impossible to use the same chemical reaction parameters for different components and ratios of waste textiles. ⑤ The technical and material costs are high, resulting in poor economic efficiency. These problems directly hinder the industrial development and application of chemical separation of polyester-cotton textiles.

[0037] Another type of separation method is the bio-enzymatic method. This method uses bio-enzymes to act on cotton fibers, accelerating the hydrolysis of cellulose in them, so as to achieve the purpose of separating polyester and cotton. However, the drawback of this method is that it is difficult to cultivate efficient, stable and adaptable bio-enzymes to process waste textiles with complex composition and uncertain content in practice.

[0038] Therefore, based on the shortcomings and problems faced by traditional separation technologies for polyester-cotton textiles, such as... Figure 1 As shown, this application provides a method for separating polyester-cotton textiles, which comprise polyester and cotton fibers. The separation method includes the following steps:

[0039] S1. Cutting: Cutting polyester-cotton textiles to obtain scraps of fabric.

[0040] S2, Opening: The scraps of fabric are opened to obtain bundled fibers;

[0041] S3, Air flotation sedimentation: Bundle fibers are dispersed in an air flotation sedimentation solution. Gas is continuously introduced into the bottom of the air flotation sedimentation solution to form rising bubbles. Part of the bundle fibers adheres to the bubbles and floats to the liquid surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0042] S4. Disperse the sinking fiber components in the air flotation sedimentation solution and perform air flotation sedimentation treatment;

[0043] S5. Repeat step S4 2 to 3 times;

[0044] The air flotation sedimentation solution includes a surfactant and a metal salt. The surfactant includes at least one of methyl isobutyl methanol (MIBC), laurylamine acetate (DDA), and calcium lignosulfonate (CALS). The metal salt includes at least one of calcium chloride, calcium sulfate, and sodium chloride.

[0045] It is understood that the specific cutting method in step S1 is not particularly limited in this application. Without departing from the inventive concept of this application, any known cutting method commonly used in the art can be applied to this application. The following are merely illustrative examples and not a limitation on the scope of protection. In some embodiments, a razor is used to cut the polyester-cotton fabric into shredded pieces.

[0046] In some embodiments, in step S2, the fabric scraps obtained in step S1 are fed into an opening machine, and continuous opening is performed using a feeding roller and an opening licker roller, so that the tangled polyester-cotton fibers in the fabric scraps are torn apart into bundles of fibers, and the impurities therein are thrown out along the tangential direction of the opening licker roller under the action of centrifugal force.

[0047] In some embodiments, the length of the bundled fibers obtained in step S2 is 1mm to 5mm, including but not limited to 1mm, 1.5mm, 2mm, 2.5mm, 3mm, 3.5mm, 4mm, 4.5mm, and 5mm. That is, through the shearing in step S1 and the opening step in step S2, fibers with a length between 1mm and 5mm are formed, disrupting the intertwined and interwoven structure between polyester and cotton fibers. This prevents the polyester and cotton fibers from becoming excessively entangled and unable to separate in the air flotation sedimentation solution, even though they are mixed together (e.g., ...). Figure 2 (As shown).

[0048] In some embodiments, in step S3, the mass concentration of the surfactant is 0.05% to 0.5%, including but not limited to 0.05%, 0.1%, 0.15%, 0.2%, 0.25%, 0.3%, 0.35%, 0.4%, 0.45%, and 0.5%.

[0049] This application involves adding surfactants to an air flotation sedimentation solution, which then act on the surface of polyester-cotton fibers to alter their surface properties. This results in increased differences in the surface properties of polyester-cotton textile fibers with different compositions; for example, cotton fibers exhibit stronger hydrophilicity, while polyester fibers exhibit stronger hydrophobicity.

[0050] In some embodiments, in step S3, the mass concentration of the metal salt is 10% to 40%, including but not limited to 10%, 15%, 20%, 25%, 30%, 35%, and 40%.

[0051] This application involves adding metal salts to the air flotation sedimentation solution to adjust the density of the solution, thereby better utilizing the density difference between polyester fibers, cotton fibers, and the air flotation sedimentation solution to achieve different buoyancy differences.

[0052] In some embodiments, in step S3, the sheared and loosened bundled fibers are added to the air flotation sedimentation solution and stirred thoroughly, according to a solid-liquid ratio of 0.5 g / L to 5 g / L between the bundled fibers and the air flotation sedimentation solution. The solid-liquid ratio between the bundled fibers and the air flotation sedimentation solution includes, but is not limited to, 0.5 g / L, 1 g / L, 1.5 g / L, 2 g / L, 2.5 g / L, 3 g / L, 3.5 g / L, 4 g / L, 45 g / L, and 5 g / L, facilitating the handling and treatment of the suspension throughout the separation and recovery process.

[0053] In some embodiments, in step S3, a gas distributor is used to continuously introduce gas into the bottom of the air flotation sedimentation solution, so that the gas forms tiny bubbles that fill the air flotation sedimentation solution from bottom to top.

[0054] In some embodiments, the gas continuously introduced into the bottom of the flotation sedimentation solution can be air or oxygen, which are insoluble in water.

[0055] In some implementations, the number of gas distributors is one or more.

[0056] In this application, when separating polyester-cotton fibers, air or oxygen that is insoluble in water is introduced into the air flotation sedimentation solution near the bottom through a gas distributor. Under the action of a foaming agent, the introduced air or oxygen forms bubbles in the air flotation sedimentation solution and rises.

[0057] In some embodiments, the flow rate of the introduced gas is 0.05 L / min to 0.5 L / min, including but not limited to 0.05 L / min, 0.1 L / min, 0.15 L / min, 0.2 L / min, 0.2 L / min, 0.3 L / min, 0.35 L / min, 0.4 L / min, 0.45 L / min, and 0.5 L / min.

[0058] In some embodiments, the following steps are included before the cutting process: cleaning and disinfecting the polyester-cotton fabric.

[0059] In some embodiments, after the air flotation sedimentation treatment, the following step is also included: removing the floating fiber components using a scraper or scraper net.

[0060] In this application, a scraping plate or scraping net is used to remove the floating fiber components. The entire device does not require manual operation. The scraping mechanism is supported by buoyancy and can change according to the change of liquid level, always keeping it in contact with the liquid surface. There is no need to manually adjust the height, achieving fully automated scraping.

[0061] Understandably, in step S3, most of the polyester fibers in the bundled fibers will adhere to the air bubbles and float to the surface of the liquid to form the floating fiber component, while most of the cotton fibers will sink to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0062] To further improve the separation effect of polyester fiber and cotton fiber, this application further conducts a new round or more of air flotation sedimentation treatment on the collected sinking fiber components. Through multi-stage air flotation sedimentation, the proportion of polyester fiber in the sinking fiber components that sink to the bottom of the air flotation sedimentation solution can be reduced to less than 10%, and the proportion of cotton fiber can exceed 90%.

[0063] This application utilizes the differences in the physicochemical properties of polyester fiber and cotton fiber to separate them using mechanical and physical methods such as shearing and opening. This method preserves the original characteristics of the fibers to the maximum extent, ensuring the demand for high-value utilization of the fibers and providing more possibilities for subsequent resource utilization. At the same time, it is less likely to cause environmental pollution and reduces production costs.

[0064] This application utilizes the differences in physicochemical properties between different textile fiber components to achieve separation by means of surfactants or chemical modification. This separation method is highly adaptable to the separation process of polyester-cotton textiles with different component ratios.

[0065] The technical solution of this application will be described in detail below with reference to specific embodiments.

[0066] Example 1

[0067] S1. The polyester-cotton textile (30% polyester fiber and 70% cotton fiber) is cut to obtain scraps of fabric.

[0068] S2. The scraps of fabric are opened to obtain bundled fibers with a length of 1mm to 5mm.

[0069] S3. The bundled fibers are added to the prepared air flotation sedimentation solution in the flotation tank and stirred to fully disperse the bundled fibers in the air flotation sedimentation solution. Then, air is continuously introduced into the bottom of the flotation tank using a gas distributor at a gas flow rate of 0.5 L / min. The air forms small bubbles that fill the air flotation sedimentation solution from bottom to top. This causes some of the bundled fibers to adhere to the bubbles and float to the surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0070] The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 2.5 g / L. The air flotation sedimentation solution includes surfactants and metal salts. The surfactants include methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate, with a mass concentration of 0.25%. The metal salts include calcium chloride, calcium sulfate, and sodium chloride, with a mass concentration of 25%.

[0071] S4. Disperse the sinking fiber component from step S3 in the air flotation sedimentation solution and perform air flotation sedimentation treatment.

[0072] S5. Repeat step S4 twice.

[0073] The collected sinking fiber components contain more than 90% cotton fibers.

[0074] Example 2

[0075] To remove dirt and disinfect polyester-cotton textiles.

[0076] S1. The polyester-cotton textile (30% polyester fiber and 70% cotton fiber) is cut to obtain scraps of fabric.

[0077] S2. The scraps of fabric are opened to obtain bundled fibers with a length of 1mm to 5mm.

[0078] S3. The bundled fibers are added to the prepared air flotation sedimentation solution in the flotation tank and stirred to fully disperse the bundled fibers in the air flotation sedimentation solution. Then, air is continuously introduced into the bottom of the flotation tank using a gas distributor at a gas flow rate of 0.5 L / min. The air forms small bubbles that fill the air flotation sedimentation solution from bottom to top. This causes some of the bundled fibers to adhere to the bubbles and float to the surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0079] The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 2.5 g / L. The air flotation sedimentation solution includes surfactants and metal salts. The surfactants include methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate, with a mass concentration of 0.25%. The metal salts include calcium chloride, calcium sulfate, and sodium chloride, with a mass concentration of 25%.

[0080] S4. Disperse the sinking fiber component from step S3 in the air flotation sedimentation solution and perform air flotation sedimentation treatment.

[0081] S5. Repeat step S4 twice.

[0082] The collected sinking fiber components contain more than 90% cotton fibers.

[0083] Example 3

[0084] To remove dirt and disinfect polyester-cotton textiles.

[0085] S1. The polyester-cotton textile (30% polyester fiber and 70% cotton fiber) is cut to obtain scraps of fabric.

[0086] S2. The scraps of fabric are opened to obtain bundled fibers with a length of 1mm to 5mm.

[0087] S3. The bundled fibers are added to the prepared air flotation sedimentation solution in the flotation tank and stirred to fully disperse the bundled fibers in the air flotation sedimentation solution. Then, air is continuously introduced into the bottom of the flotation tank using a gas distributor at a gas flow rate of 0.5 L / min. The air forms small bubbles that fill the air flotation sedimentation solution from bottom to top. This causes some of the bundled fibers to adhere to the bubbles and float to the surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0088] The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 2.5 g / L. The air flotation sedimentation solution includes surfactants and metal salts. The surfactants include methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate, with a mass concentration of 0.25%. The metal salts include calcium chloride, calcium sulfate, and sodium chloride, with a mass concentration of 25%.

[0089] A scraper is used to remove the floating fiber components.

[0090] S4. Disperse the sinking fiber component from step S3 in the air flotation sedimentation solution and perform air flotation sedimentation treatment.

[0091] S5. Repeat step S4 twice.

[0092] The collected sinking fiber components contain more than 90% cotton fibers.

[0093] Example 4

[0094] To remove dirt and disinfect polyester-cotton textiles.

[0095] S1. The polyester-cotton textile (40% polyester fiber and 60% cotton fiber) is cut to obtain fabric scraps.

[0096] S2. The scraps of fabric are opened to obtain bundled fibers with a length of 1mm to 5mm.

[0097] S3. The bundled fibers are added to the prepared air flotation sedimentation solution in the flotation tank and stirred to fully disperse the bundled fibers in the air flotation sedimentation solution. Then, air is continuously introduced into the bottom of the flotation tank using a gas distributor at a gas flow rate of 0.5 L / min. The air forms small bubbles that fill the air flotation sedimentation solution from bottom to top. This causes some of the bundled fibers to adhere to the bubbles and float to the surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0098] The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 2.5 g / L. The air flotation sedimentation solution includes surfactants and metal salts. The surfactants include methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate, with a mass concentration of 0.25%. The metal salts include calcium chloride, calcium sulfate, and sodium chloride, with a mass concentration of 25%.

[0099] A scraper is used to remove the floating fiber components.

[0100] S4. Disperse the sinking fiber component from step S3 in the air flotation sedimentation solution and perform air flotation sedimentation treatment.

[0101] S5. Repeat step S4 3 times.

[0102] The collected sinking fiber components contain more than 90% cotton fibers.

[0103] Example 5

[0104] To remove dirt and disinfect polyester-cotton textiles.

[0105] S1. The polyester-cotton textile (30% polyester fiber and 70% cotton fiber) is cut to obtain scraps of fabric.

[0106] S2. The scraps of fabric are opened to obtain bundled fibers with a length of 1mm to 5mm.

[0107] S3. The bundled fibers are added to the prepared air flotation sedimentation solution in the flotation tank and stirred to fully disperse the bundled fibers in the air flotation sedimentation solution. Then, air is continuously introduced into the bottom of the flotation tank using a gas distributor at a gas flow rate of 0.05 L / min. The air forms small bubbles that fill the air flotation sedimentation solution from bottom to top. This causes some of the bundled fibers to adhere to the bubbles and float to the surface to form the floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form the sinking fiber component.

[0108] The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 1 g / L. The air flotation sedimentation solution includes surfactants and metal salts. The surfactants include methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate, with a mass concentration of 0.1%. The metal salts include calcium chloride, calcium sulfate, and sodium chloride, with a mass concentration of 30%.

[0109] A scraper is used to remove the floating fiber components.

[0110] S4. Disperse the sinking fiber component from step S3 in the air flotation sedimentation solution and perform air flotation sedimentation treatment.

[0111] S5. Repeat step S4 twice.

[0112] The collected sinking fiber components contain more than 90% cotton fibers.

[0113] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0114] The embodiments described above are merely illustrative of several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A method for separating polyester-cotton textiles, wherein the polyester-cotton textiles comprise polyester and cotton fibers, characterized in that, The steps include the following: S1. Cutting: The polyester-cotton textile is cut to obtain scraps of fabric. S2. Opening: The fabric scraps are opened to obtain bundled fibers; S3, Air flotation sedimentation: The bundled fibers are dispersed in an air flotation sedimentation solution. Gas is continuously introduced into the bottom of the air flotation sedimentation solution to form rising bubbles. Part of the bundled fibers adheres to the bubbles and floats to the liquid surface to form a floating fiber component, while the other part sinks to the bottom of the air flotation sedimentation solution to form a sinking fiber component. S4. Disperse the sinking fiber component in an air flotation sedimentation solution and perform air flotation sedimentation treatment; S5. Repeat step S4 2-3 times; The air flotation precipitation solution includes a surfactant and a metal salt. The surfactant includes at least one of methyl isobutyl methanol, laurylamine acetate, and calcium lignosulfonate. The metal salt includes at least one of calcium chloride, calcium sulfate, and sodium chloride. The length of the bundled fibers is 1mm to 5mm; The surfactant has a mass concentration of 0.05% to 0.5%. The mass concentration of the metal salt is 10% to 40%.

2. The separation method according to claim 1, characterized in that, A gas distributor is used to introduce gas into the bottom of the air flotation sedimentation solution, so that the gas forms bubbles that fill the air flotation sedimentation solution from bottom to top.

3. The separation method according to claim 2, characterized in that, The gas flow rate is 0.05 L / min to 0.5 L / min.

4. The separation method according to claim 2, characterized in that, The number of gas distributors may be one or more.

5. The separation method according to claim 1, characterized in that, The solid-liquid ratio of the bundled fibers to the air flotation sedimentation solution is 0.5 g / L to 5 g / L.

6. The separation method according to claim 1, characterized in that, Before the cutting process, the following steps are also included: cleaning and disinfecting the polyester-cotton textile.

7. The separation method according to claim 1, characterized in that, After step S3, the following step is also included: removing the floating fiber components using a scraper or scraping net.

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