Mask recycling system and method

Abstract

The invention relates to the technical field of solid waste recycling, and discloses a mask recycling system and method. The mask recycling system comprises a smashing unit used for smashing and screening masks to obtain mask powder containing iron, aluminum, polar organic matter and non-polar organic matter; the iron powder separation unit is used for removing iron in the mask powder to obtain iron-removed mask powder and iron powder; the saline-alkaline pool unit is used for removing aluminum in the iron-removed powder to obtain aluminum-removed mask powder; the non-polar substance recovery unit is used for separating polar organic matters in the dealuminated powder to obtain non-polar organic matter powder containing polyethylene and polypropylene; and the drying flotation unit is used for separating polyethylene from the non-polar organic matter powder to obtain polypropylene. According to the system and method, iron, aluminum, polar organic matter and polyethylene in mask powder are sequentially removed according to a specific sequence, thorough separation of all the materials is achieved, and the different materials are recycled respectively.

Description

Technical Field

[0001] The present invention relates to the technical field of solid waste recycling, and in particular to a mask recycling system and method. Background Art

[0002] The main chemical components of medical surgical masks are polypropylene (accounting for over 90%) and various additives (such as plasticizers, antioxidants, UV absorbers, surfactants, and intermediates, accounting for less than 10%). Their structure generally consists of a face, nose strip, and ear straps. The face comprises an outer layer, a middle layer, and an inner layer. The outer layer is typically a spunbond non-woven fabric primarily composed of polypropylene, which blocks larger particles such as droplets and dust, providing a preliminary filtration effect. The middle layer is a meltblown non-woven fabric, also primarily composed of polypropylene, with finer fibers and excellent filtration properties, effectively blocking tiny particles such as bacteria and viruses. The inner layer is typically a soft, skin-friendly non-woven fabric, mostly made of polyester or polypropylene. Its primary function is to absorb exhaled moisture and provide comfort for the wearer. The nose strip is typically made of plastic or metal (aluminum), with common plastic nose strips also often made of polypropylene. Metal nose strips are typically made of galvanized iron or aluminum wire, often coated in a layer of plastic or rubber. Ear straps are made of elastic materials, common ones include spandex, polyester fiber, polyethylene, etc. Some ear straps may add a small amount of additives, such as anti-aging agents, softeners, etc., to improve the performance and usage experience of the ear straps.

[0003] The research background and significance of mask recycling have many values, including environmental protection, resource recycling, technological innovation, economic benefits, and social responsibility. Therefore, the recycling of discarded masks not only helps reduce environmental pollution but also achieves resource recycling through the preparation of high-performance, high-value-added polymer-based composite materials, with significant ecological and economic benefits.

[0004] The defects of the traditional mask recycling process are: 1. Incomplete separation: Metal impurities such as iron powder are not completely removed, resulting in low purity of recycled materials, affecting the quality of subsequent reprocessing and application. 2. Poor impurity removal effect: Usually only simple water washing or physical screening is used to remove impurities, and the removal of organic impurities in materials such as PP (polypropylene) is limited, which reduces the performance of recycled PP and can only be used in occasions with lower quality requirements, limiting the reuse path. 3. Low flotation efficiency: Failure to use a suitable flotation process results in poor separation of plastics such as PE (polyethylene) during flotation, and a high impurity content in the recycled PE, which affects its reuse value and may cause waste of resources. 4. Narrow application scope: The traditional process has a relatively single application of recycled materials and has not fully explored the characteristics of different materials for diversified reuse. As a result, some recyclables are difficult to be effectively utilized due to quality or performance issues, reducing the overall benefits of the entire mask recycling. Summary of the Invention

[0005] The purpose of the present invention is to overcome the problems in the prior art of the traditional mask recycling process that the separation of different materials is not thorough, the impurity removal effect is poor, resulting in low purity of the recycled polypropylene and relatively single recycled materials. A mask recycling system and method are provided. The system and method remove iron, aluminum, polar organic matter and polyethylene from mask powder in a specific order, thereby achieving a thorough separation between the materials, allowing different materials to be recycled separately, and obtaining polypropylene with higher purity.

[0006] In order to achieve the above objectives, the present invention provides a mask recycling system, which includes:

[0007] A crushing unit is used to crush and screen the mask to obtain mask powder containing iron, aluminum, polar organic matter and non-polar organic matter;

[0008] An iron powder separation unit is used to remove iron from the mask powder to obtain deironized mask powder and iron powder;

[0009] A salt-alkali tank unit is used to remove aluminum from the de-ironized powder to obtain dealuminated mask powder;

[0010] a non-polar substance recovery unit for separating polar organic matter from the dealuminated powder to obtain non-polar organic powder containing polyethylene and polypropylene;

[0011] Dry flotation unit is used to separate polyethylene from non-polar organic powder to obtain polypropylene.

[0012] Preferably, the pulverizing unit comprises a first blower, a pulverizing device, a second blower and a collecting device, which are sequentially arranged from top to bottom; the pulverizing device comprises an outer shell and an inner cavity; a cross-cutting pulverizer and a shearing pulverizer are sequentially arranged in the inner cavity from top to bottom; an air inlet is provided at the top of the pulverizing device; the second blower is located at one side of the bottom of the pulverizing device; and an air outlet opposite to the second blower is provided at the other side of the bottom of the pulverizing device;

[0013] The mask enters the pulverizing device from the blast inlet under the action of the wind force of the first blower, and is pulverized in turn by the cross-cutting pulverizer and the shearing pulverizer to obtain a pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out into small-particle mask powder with a particle size of ≤0.5 mm under the action of the lateral wind force applied by the second blower, and the small-particle mask powder enters the iron powder separation unit through the blast outlet.

[0014] Preferably, the collecting device is used to collect large-particle mask powder with a particle size greater than 0.5 mm screened out under the action of the lateral wind force applied by the second blower.

[0015] Preferably, the iron powder separation unit comprises a conveyor belt and an electromagnet arranged on the upper portion of the conveyor belt;

[0016] The mask powder from the crushing unit reaches the conveyor belt through the air blast outlet, and the iron in the mask powder is adsorbed by the electromagnet to obtain iron powder and de-ironized mask powder.

[0017] Preferably, the saline-alkali pool unit comprises a saline-alkali pool having a powder inlet, a first liquid adding port, a first liquid discharge port and a powder outlet, wherein a push rod is provided at the powder inlet, and the first liquid adding port is used to add alkali solution into the saline-alkali pool;

[0018] The de-ironization mask powder from the iron powder separation unit enters the saline-alkali pool from the powder inlet, and the aluminum in the de-ironization mask powder reacts with the alkali solution in the saline-alkali pool, and the resulting mixed solution is discharged from the first liquid discharge port; the de-ironization mask powder that cannot react floats on the liquid surface and is driven to the powder discharge port by the pushing rod to be discharged, thereby obtaining dealuminated mask powder;

[0019] Preferably, the saline-alkali pool is a multi-chamber saline-alkali pool, and a powder discharge port is provided between two adjacent saline-alkali pools. The deironing mask powder floating on the liquid surface enters the saline-alkali pool of the next chamber from the upper chamber through the powder discharge port under the action of the pushing rod, and is finally discharged from the powder outlet.

[0020] Preferably, the non-polar substance recovery unit comprises a dissolution tank, a decompression device and a filtering device, the dissolution tank is provided with a second liquid addition port and a second liquid discharge port, the second liquid addition port is used to add a polar solvent to the dissolution tank;

[0021] The dealuminated mask powder from the salt-alkali pool unit is discharged from the powder outlet and enters the dissolution tank. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank, and the non-polar organic matter is suspended in the solution. The resulting mixture is discharged from the second liquid discharge port and enters the filtration device. It is filtered under the action of the decompression device, and the obtained solid phase product is non-polar organic powder.

[0022] Preferably, the dry flotation unit comprises a heating device and a flotation tank, the flotation tank comprises an input port, a third liquid addition port and a third liquid discharge port, the third liquid addition port is used to add a wetting agent aqueous solution into the flotation tank;

[0023] The non-polar organic powder from the non-polar substance recovery unit enters the heating device through a conveying pipe, and is heated to volatilize the solution on the surface of the non-polar organic powder. The heated non-polar organic powder enters the flotation tank from the input port, and polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats. The mixture of polyethylene and wetting agent is discharged from the third liquid discharge port to obtain polypropylene.

[0024] Preferably, a fan is provided in the flotation tank to accelerate the floating of polypropylene.

[0025] A second aspect of the present invention provides a mask recycling method, which is implemented using the mask recycling system described above. The mask recycling method includes:

[0026] The mask is crushed and screened to obtain mask powder, wherein the mask powder contains iron, aluminum, polar organic matter and non-polar organic matter;

[0027] Separating the iron from the mask powder to obtain deironized mask powder and iron powder;

[0028] Separate and remove aluminum from the de-ironized powder to obtain dealuminated mask powder;

[0029] Removing polar organic matter from dealuminated mask powder to obtain non-polar organic powder, wherein the non-polar organic powder contains polyethylene and polypropylene;

[0030] The polyethylene in the non-polar organic powder is separated to obtain polypropylene.

[0031] Preferably, the process of separating and removing aluminum from the de-ironized powder to obtain the dealuminated mask powder includes: reacting the aluminum in the de-ironized mask powder with an alkali solution; and discharging the unreacted de-ironized mask powder after floating on the liquid surface to obtain the dealuminated mask powder.

[0032] Preferably, the alkali solution is sodium hydroxide solution and / or potassium hydroxide solution.

[0033] Preferably, the process of removing the polar organic matter in the dealuminated mask powder to obtain the non-polar organic powder includes: mixing the dealuminated mask powder with a polar solvent, dissolving the polar organic matter in the dealuminated mask powder in the polar solvent, and suspending the non-polar organic matter in the solution, and then filtering under reduced pressure to obtain a solid phase product as the non-polar organic powder.

[0034] Preferably, the polar solvent is ethylene glycol and / or dimethyl sulfoxide.

[0035] Preferably, the process of separating polyethylene from non-polar organic powder to obtain polypropylene includes: heating the non-polar organic powder to volatilize the surface of the non-polar organic powder, then mixing the heated non-polar organic powder with a wetting agent, whereby the polyethylene sinks under the action of the wetting agent aqueous solution and the polypropylene floats, and the polypropylene is obtained after separation.

[0036] Preferably, the wetting agent aqueous solution is a calcium lignin sulfonate aqueous solution and / or a sodium lauryl sulfate aqueous solution.

[0037] Compared with the prior art, the present invention has at least the following technical effects:

[0038] (1) The mask recycling system and method provided by the present invention removes iron, aluminum, polar organic matter and polyethylene from mask powder in a specific order, achieving a thorough separation between the materials, allowing different materials to be recycled separately, and simultaneously obtaining iron powder and polypropylene with higher purity.

[0039] Preferably, the present invention can effectively separate metal components such as iron powder from mask materials through magnetic separation technology, thereby improving the purity of recycled materials, enabling different materials to be better recycled separately, and achieving refined separation.

[0040] Preferably, polar organic impurities in mask powder are removed by adding polar organic solvents. Compared with traditional physical screening or simple washing, organic impurities can be removed more deeply, thereby improving the quality of recycled polypropylene and broadening its scope of reuse.

[0041] Preferably, an aqueous wetting agent solution, particularly an aqueous solution of calcium lignin sulfonate, is used in the flotation unit for flotation. Polypropylene floats because it has a lower density than water and is hydrophilic, while polyethylene sinks because calcium lignin sulfonate is adsorbed on its surface, making it hydrophilic. This makes the flotation process more efficient, facilitates the separation of polypropylene and polyethylene, and ensures the quality of the recovered polypropylene and polyethylene.

[0042] (2) The present invention recycles polypropylene and polyethylene respectively through a multi-step process, which can be used in construction sites, plastic manufacturing, textile products, etc., to create economic value; and the recycled polypropylene and polyethylene can be reused in multiple ways. Specifically, the recycled polypropylene can be used for melt spinning, and the recycled polyethylene can be used for melt regeneration and recycling, giving full play to the characteristics of different materials, realizing efficient recycling of resources, and improving the economic value and environmental benefits of the entire recycling process.

[0043] (3) The present invention also separates iron and aluminum, which provide raw materials for some factories, thereby improving the resource recovery rate.

[0044] (4) The system and method of the present invention reduce labor costs and can carry out large-scale mask recycling, while reducing the generation of pollutants and protecting the environment. BRIEF DESCRIPTION OF THE DRAWINGS

[0045] Figure 1 Schematic diagram of the mask recycling system of the present invention.

[0046] Description of Reference Numerals

[0047] 1. First blower; 2. Cross-cutting pulverizer; 3. Shearing pulverizer; 4. Blast outlet; 5. Second blower; 6. Collecting device; 7. Electromagnet; 8. Conveyor belt; 9. Salt-alkali tank; 10. First liquid adding port; 11. Powder inlet; 12. Push rod; 13. First liquid discharge port; 14. Powder discharge port; 15. Powder discharge port; 16. Dissolving tank; 17. Second liquid adding port; 18. Second liquid discharge port; 19. Pressure reducing device; 20. Filtering device; 21. Heating device; 22. Flotation tank; 23. Input port; 24. Third liquid adding port; 25. Fan; 26. Third liquid discharge port; 27. Conveying pipeline; 28. Casing; 29. ​​Inner cavity; 30. Blast inlet; 40. Crushing unit; 50. Iron powder separation unit; 60. Salt-alkali tank unit; 70. Non-polar substance recovery unit; 80. Drying flotation unit. DETAILED DESCRIPTION

[0048] The following describes the specific embodiments of the present invention in detail with reference to the accompanying drawings. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present invention and are not intended to limit the present invention.

[0049] The endpoints of the ranges and any values ​​disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoints of each range, the endpoints of each range and individual point values, and the individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered to be specifically disclosed herein.

[0050] like Figure 1 As shown, the mask recycling system provided by the present invention includes a crushing unit 40, an iron powder separation unit 50, a salt-alkali pool unit 60, a non-polar substance recovery unit 70 and a dry flotation unit 80, wherein the crushing unit 40 is used to crush and screen the mask to obtain mask powder containing iron, aluminum, polar organic matter and non-polar organic matter; the iron powder separation unit 50 is used to remove iron from the mask powder to obtain de-ironized mask powder and iron powder; the salt-alkali pool unit 60 is used to remove aluminum from the de-ironized powder to obtain dealuminated mask powder; the non-polar substance recovery unit 70 is used to separate the polar organic matter from the dealuminated powder to obtain non-polar organic powder containing polyethylene and polypropylene; the dry flotation unit 80 is used to separate the polyethylene from the non-polar organic powder to obtain polypropylene.

[0051] In the mask recycling system of the present invention, the mask is first crushed in the crushing unit 40 to obtain mask powder. The powdered material with smaller particles is conducive to improving the recovery rate and separation efficiency of subsequent materials; in the iron powder separation unit 50, the iron in the mask powder is separated from other components to obtain iron powder and deironized mask powder respectively. The iron is separated first. On the one hand, it can avoid the loss of iron powder and improve the recovery rate of iron. On the other hand, after the iron is separated, other materials in the deironized mask powder are easier to recover, and the recycled material has higher purity; in the salt-alkali pool unit 60, the deironized mask powder is separated. The aluminum in the dealuminous mask is removed to obtain a dealuminized mask powder mainly containing polar organic matter and non-polar organic matter. In this step, the aluminum reacts with the alkali solution in the saline alkali pool to generate aluminum salt, and the part that cannot react mainly contains polar organic matter and non-polar organic matter, thereby realizing the separation of aluminum and organic matter; in the non-polar substance recovery unit 70, the polar organic matter and the non-polar organic matter in the dealuminized mask powder are separated, and after the polar organic matter is removed, a non-polar organic powder containing polyethylene and polypropylene is obtained; in the dry flotation unit 80, the polyethylene and polypropylene are separated to obtain polypropylene with higher purity.

[0052] In the present invention, the masks used for recycling can be common types of masks in the field, such as ordinary masks, ordinary medical masks and medical surgical masks, preferably medical surgical masks. The polar organic matter is generally derived from additives such as anti-aging agents and softeners, and the non-polar organic matter includes polypropylene and polyethylene.

[0053] like Figure 1 As shown, the crushing unit 40 includes a first blower 1, a crushing device, a second blower 5 and a collecting device 6 arranged in sequence from top to bottom. The crushing device includes an outer shell 28 and an inner cavity 29. A cross-cutting crusher 2 and a shearing crusher 3 are arranged in sequence from top to bottom in the inner cavity. The top of the crushing device has an air inlet 30. The second blower 5 is located on one side of the bottom of the crushing device. The other side of the bottom of the crushing device is provided with an air outlet 4 opposite to the second blower 5.

[0054] The working process of the crushing unit 40 is as follows: the mask enters the crushing device from the blast inlet 30 under the action of the wind force of the first blower 1, and is crushed in turn by the cross-cutting crusher 2 and the shearing crusher 3 to obtain a crushed mask material with a particle size of 3-5 mm. The crushed mask material is screened out with small-particle mask powder with a particle size of ≤0.5 mm under the action of the lateral wind force applied by the second blower 5, and the small-particle mask powder enters the iron powder separation unit 50 through the blast outlet 4.

[0055] In the crushing unit 40 , the first blower 1 is disposed at the air inlet 30 . The function of the first blower 1 is to accelerate the efficiency of the mask entering the air inlet 30 , prevent blockage, and improve the efficiency of the mask crushing.

[0056] In the present invention, the function of the collecting device 6 is to collect large-particle mask powder with a particle size greater than 0.5 mm screened out by the lateral wind force exerted by the second blower 5. During the pulverization process, the mask enters the cross-cutting grinder 2 under the action of gravity for preliminary pulverization, and then enters the shearing grinder 3 for thorough pulverization. After the two pulverizations, the pulverized mask material falls to the bottom of the pulverization device under the action of gravity. The large-particle mask powder that is not completely pulverized after being pulverized by the cross-cutting grinder 2 and the shearing grinder 3 cannot enter the blast outlet 4 under the lateral wind force of the second blower 5, and is finally collected in the collecting device 6 and pulverized again.

[0057] like Figure 1 As shown, the iron powder separation unit 50 includes a conveyor belt 8 and an electromagnet 7 arranged on the upper part of the conveyor belt 8. In one embodiment, the conveyor belt 8 can be located directly below the blast outlet 4. The small-particle mask powder from the crushing unit 40 falls onto the conveyor belt 8 through the blast outlet 4. During the conveying process of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8. The iron powder is separated under the attraction of magnetic force and adsorbed on the electromagnet 7. What remains on the conveyor belt 8 is the mask powder after the iron is removed. Finally, separated iron powder and de-ironized mask powder are obtained, and the purity of the iron powder is relatively high. In the present invention, the small-particle mask powder is transported by the conveyor belt 8, which can be evenly separated, improve the absorption efficiency of the iron powder, and improve the removal rate and recovery rate of the iron powder. The iron powder collected on the electromagnet 7 can be used to re-ironize.

[0058] In the present invention, Figure 1As shown, the brine pool unit 60 includes a brine pool 9, which has a powder inlet 11, a first liquid addition port 10, a first liquid discharge port 13 and a powder outlet 15. A pushing rod 12 is provided at the powder inlet 11. The first liquid addition port 10 is used to add alkali solution to the brine pool 9. The location of the first liquid addition port 10 is not limited, as long as alkali solution can be added to the brine pool 9. For example, it can be set above the powder inlet 11. In one embodiment, the first drain port 13 is disposed at the bottom of the saline-alkali pool 9; the de-iron mask powder from the conveyor belt 8 in the iron powder separation unit 50 enters the saline-alkali pool 9 from the powder inlet 11, and the aluminum in the de-iron mask powder reacts with the alkali solution in the saline-alkali pool 9 to generate aluminum salt. The mixed solution containing alkali solution and aluminum salt obtained in the saline-alkali pool 9 is discharged from the first drain port 13; the de-iron mask powder containing polar organic matter and non-polar organic matter cannot react and will float to the liquid surface. The pushing rod 12 is driven (pushed) to the powder outlet 15 for discharge. The de-aluminized mask powder containing polar organic matter and non-polar organic matter is discharged from the powder outlet 15. The aluminum-containing solution collected by the first drain port 13 can be used as industrial aluminum liquid.

[0059] In some embodiments, the alkali solution may be a sodium hydroxide solution and / or a potassium hydroxide solution. Furthermore, the alkali solution can dissolve esters in the mask. If the mask contains lipids, a mixed solution containing alkali solution, aluminum salt, and esters will be discharged from the first liquid discharge port 13.

[0060] In order to improve the removal rate of aluminum in the deironing mask powder, the saline alkali pool can be a multi-chamber saline alkali pool, and a powder discharge port 14 is provided between two adjacent saline alkali pools. Under the action of the pushing rod 12, the deironing mask powder floating on the liquid surface passes through the powder discharge port 14 from the upper chamber saline alkali pool into the lower chamber saline alkali pool, and is finally discharged from the powder discharge port 15. In one embodiment, the saline alkali pool 9 is a three-chamber saline alkali pool, the first chamber saline alkali pool is provided with a powder inlet 11, a powder discharge port 14 is provided between the first chamber saline alkali pool and the second chamber saline alkali pool, and between the second chamber saline alkali pool and the third chamber saline alkali pool, the three chamber saline alkali pool is provided with a powder discharge port 15, and the first chamber saline alkali pool, the second chamber saline alkali pool and the third chamber saline alkali pool are all provided with a first liquid addition port 10, a pushing rod 12 and a first liquid discharge port 13.

[0061] After the deironing mask powder on the conveyor belt 8 in the iron powder separation unit 50 enters the first chamber saline-alkali pool from the powder inlet 11 of the first chamber saline-alkali pool, the aluminum in the deironing mask powder reacts with the alkali solution in the first chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first drain port 13 in the first chamber saline-alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface, and will be driven by the pushing rod 12 in the first chamber saline-alkali pool to the powder discharge port 14 between the first chamber saline-alkali pool and the second chamber saline-alkali pool, and enter the second chamber saline-alkali pool; the residual aluminum in the deironing mask powder containing polar organic matter and non-polar organic matter reacts with the alkali solution in the second chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first drain port 13 in the second ... The deironing mask powder containing organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the second-chamber saline-alkali pool to the powder discharge port 14 between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool and enter the third-chamber saline-alkali pool. The residual aluminum in the deironing mask powder containing polar organic matter and non-polar organic matter reacts with the alkali solution in the third-chamber saline-alkali pool to generate aluminum salt. The mixed solution containing alkali solution and aluminum salt is discharged from the first liquid discharge port 13 in the third-chamber saline-alkali pool. The deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the third-chamber saline-alkali pool to the powder discharge port 15 of the third-chamber saline-alkali pool. The dealuminated mask powder (polar organic matter and non-polar organic matter have higher purity) is discharged from the powder discharge port 15 and enters the non-polar substance recovery unit 70.

[0062] In one embodiment, the non-polar substance recovery unit 70 includes a dissolution tank 16, a pressure reducing device 19, and a filtering device 20. The dissolution tank 16 is provided with a second liquid adding port 17 and a second liquid drain 18. The second liquid adding port 17 is used to add a polar solvent to the dissolution tank 16. The function of the dissolution tank 16 is to separate the polar organic matter and the non-polar organic matter in the dealuminated mask powder into layers, facilitating subsequent filtration and separation. In the dissolution tank 16, the polar organic matter can be dissolved in the polar solvent, while the non-polar organic matter cannot be dissolved in the polar solvent and is suspended in the solution, thereby separating into layers. Specifically, the dealuminated mask powder from the salt-alkali pool unit 6 is discharged from the powder outlet 15 and enters the dissolution tank 16. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The resulting layered mixture is discharged from the second drain port 18 and enters the filtration device 20. It is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder. The decompression device 19 can reduce the pressure and speed up the filtration speed.

[0063] In some embodiments, the polar solvent may be ethylene glycol and / or dimethyl sulfoxide.

[0064] like Figure 1 As shown, the dry flotation unit 80 includes a heating device 21 and a flotation tank 22. The flotation tank 22 includes an input port 23, a third liquid addition port 24, and a third liquid discharge port 26. The third liquid addition port 24 is used to add a wetting agent aqueous solution to the flotation tank 22. The non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through a conveying pipe 27. The non-polar organic powder is heated to volatilize the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent, etc. added in the above steps), thereby removing impurities and preventing interference with the subsequent hydrophilicity change reaction in the flotation tank 22. The heated non-polar organic powder enters the flotation tank 22 through the input port 23. Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats due to its own hydrophobicity and lower density than water. The mixture of polyethylene and the wetting agent aqueous solution is discharged from the third liquid discharge port 26. The polypropylene collected in the flotation tank 22 is high-purity polypropylene, thereby obtaining polypropylene. The polyethylene solution discharged from the third liquid discharge port 26 can be melted and reused to make plastic products after drying; the collected polypropylene can be melted and spun into weaving fabrics after drying, and can also be added to building materials to enhance toughness.

[0065] In the present invention, the aqueous wetting agent solution can be an aqueous solution of calcium lignin sulfonate and / or an aqueous solution of sodium lauryl sulfate. To improve flotation efficiency and achieve more efficient separation of polypropylene and polyethylene, the aqueous wetting agent is an aqueous solution of calcium lignin sulfonate. In some embodiments, the mass fraction of the aqueous wetting agent solution is 0.2-0.5%.

[0066] In one embodiment, a fan 25 may be provided in the flotation tank 22 , preferably provided at the lower portion of the flotation tank 22 , to accelerate the floating of polypropylene.

[0067] Furthermore, part of the remaining components in the mask except iron, aluminum, polar organic matter, polypropylene, and polyethylene are dissolved or precipitated in the alkali solution in the saline pool 9 due to the alkaline conditions and discharged from the first drain port 13; the other part is further separated and precipitated with the polar organic matter in the dissolution pool 16, and the remaining part is discharged from the third drain port 26 as the polyethylene sinks in the flotation tank 22.

[0068] In a specific embodiment, Figure 1As shown, the mask recycling system provided by the present invention includes a crushing unit 40, an iron powder separation unit 50, a salt-alkali pool unit 60, a non-polar substance recovery unit 70 and a drying flotation unit 80. The crushing unit 40 includes a first blower 1, a crushing device, a second blower 5 and a collecting device 6 arranged in sequence from top to bottom. The crushing device includes an outer shell 28 and an inner cavity 29. A cross-cutting crusher 2 and a shearing crusher 3 are arranged in sequence from top to bottom in the inner cavity. The top of the crushing device has an air inlet 30, the second blower 5 is located on one side of the bottom of the crushing device, and the other side of the bottom of the crushing device is provided with an air outlet 4 opposite to the second blower 5. The mask is at the first blower 1. Under the action of wind, it enters the pulverizing device from the blast inlet 30, and is pulverized by the cross-cutting pulverizer 2 and the shearing pulverizer 3 in sequence to obtain a pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out under the action of the transverse wind force applied by the second blower 5 to obtain small-particle mask powder with a particle size of ≤0.5 mm. The small-particle mask powder enters the iron powder separation unit 50 through the blast outlet 4. The large-particle mask powder larger than 0.5 mm that has not been completely pulverized after being pulverized by the cross-cutting pulverizer 2 and the shearing pulverizer 3 is collected in the collecting device 6 and pulverized again; the iron powder separation unit 50 includes a conveyor belt 8 and an electromagnet 7 arranged on the upper part of the conveyor belt 8. The belt 8 can be located just below the blast outlet 4, and the small-particle mask powder from the crushing unit 40 falls onto the conveyor belt 8 through the blast outlet 4. During the conveying process of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8. The iron powder is separated under the attraction of the magnetic force and adsorbed on the electromagnet 7. What remains on the conveyor belt 8 is the mask powder after the iron is removed, and finally the separated iron powder and the de-ironized mask powder are obtained; the saline-alkali pool unit 60 includes a saline-alkali pool 9, which is a three-chamber saline-alkali pool. The first-chamber saline-alkali pool is provided with a powder inlet 11, and a powder outlet 14 is provided between the first-chamber saline-alkali pool and the second-chamber saline-alkali pool, and between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool. The pool is provided with a powder outlet 15, and the first chamber saline-alkali pool, the second chamber saline-alkali pool and the third chamber saline-alkali pool are all provided with a first liquid adding port 10, a pushing rod 12 and a first liquid discharge port 13. After the deironing mask powder on the conveyor belt 8 in the iron powder separation unit 50 enters the first chamber saline-alkali pool from the powder inlet 11 of the first chamber saline-alkali pool, the aluminum in the deironing mask powder reacts with the alkali solution in the first chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing the alkali solution and the aluminum salt is discharged from the first liquid discharge port 13 in the first chamber saline-alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It is driven by the pushing rod 12 in the first chamber saline-alkali pool to the powder discharge port 14 between the first chamber saline-alkali pool and the second chamber saline-alkali pool and enters the second chamber saline-alkali pool;The residual aluminum in the deironing mask powder containing polar organic matter and non-polar organic matter reacts with the alkali solution in the second-chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first drain port 13 in the second-chamber saline-alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the second-chamber saline-alkali pool to the powder discharge port 14 between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool and enter the third-chamber saline-alkali pool; the residual aluminum in the deironing mask powder containing polar organic matter and non-polar organic matter reacts with the alkali solution in the third-chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the third-chamber saline-alkali pool. The first drain port 13 in the pool is discharged, and the de-ironization mask powder containing polar organic matter and non-polar organic matter cannot react, and will float on the liquid surface, and will be driven to the powder outlet 15 of the three-chamber saline-alkali pool by the pushing rod 12 in the three-chamber saline-alkali pool. At this time, the dealuminized mask powder obtained (the purity of polar organic matter and non-polar organic matter is higher) is discharged from the powder outlet 15 and enters the non-polar substance recovery unit 70; the non-polar substance recovery unit 70 includes a dissolving tank 16, a decompression device 19 and a filtering device 20. The dissolving tank 16 is provided with a second liquid adding port 17 and a second drain 18. The second liquid adding port 17 is used to add a polar solvent to the dissolving tank 16. The polar solvent from the saline-alkali pool The dealuminated mask powder of unit 6 is discharged from the powder outlet 15 and enters the dissolution tank 16. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The obtained layered mixture is discharged from the second drain port 18 and enters the filtration device 20. It is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder; the dry flotation unit 80 includes a heating device 21 and a flotation tank 22, and the flotation tank 22 includes an input port 23, a third liquid addition port 24 and a third drain port 26. The third liquid addition port 24 and the third drain port 26 are respectively provided. The third liquid addition port 24 is used to add a wetting agent aqueous solution to the flotation tank 22. The non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through the delivery pipe 27. The heating process causes the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent, etc. added in the previous step) to evaporate. The heated non-polar organic powder enters the flotation tank 22 through the input port 23. Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats. The polyethylene and wetting agent mixture is discharged from the third liquid discharge port 26. The polypropylene collected in the flotation tank 22 is high-purity polypropylene, thereby obtaining polypropylene.

[0069] Furthermore, the present invention also provides a mask recycling method, which is implemented using the mask recycling system described above, and the mask recycling method includes:

[0070] (1) crushing and screening the mask to obtain mask powder, wherein the mask powder contains iron, aluminum, polar organic matter and non-polar organic matter;

[0071] (2) separating the iron in the mask powder to obtain deironized mask powder and iron powder;

[0072] (3) separating and removing aluminum from the de-ironized powder to obtain dealuminated mask powder;

[0073] (4) removing polar organic matter from the dealuminated mask powder to obtain non-polar organic powder, wherein the non-polar organic powder contains polyethylene and polypropylene;

[0074] (5) Separate the polyethylene from the non-polar organic powder to obtain polypropylene.

[0075] In one embodiment, the process of crushing and screening the mask to obtain mask powder in step (1) includes: the mask enters the crushing device from the blast inlet 30 under the action of the wind force of the first blower 1, and is crushed in turn by the cross-cutting crusher 2 and the shearing crusher 3 to obtain a crushed mask material with a particle size of 3-5 mm. The crushed mask material is screened out into small-particle mask powder with a particle size of ≤0.5 mm under the action of the lateral wind force applied by the second blower 5.

[0076] In one embodiment, step (2) separates the iron in the mask powder to obtain the de-ironized mask powder and iron powder, and the process includes: small particles of mask powder fall onto the conveyor belt 8 through the air blast outlet 4; during the transportation of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8; the iron powder is separated under the attraction of the magnetic force and adsorbed on the electromagnet 7; what remains on the conveyor belt 8 is the mask powder after de-ironization, and finally separated iron powder and de-ironized mask powder are obtained.

[0077] In one embodiment, step (3) separates and removes the aluminum in the de-ironization powder to obtain the dealuminated mask powder, which includes: reacting the aluminum in the de-ironization mask powder with alkali solution; the de-ironization mask powder that cannot react floats on the liquid surface and is discharged to obtain the dealuminated mask powder. More specifically, the de-ironization mask powder enters the saline-alkali pool 9 from the powder inlet 11, and the aluminum in the de-ironization mask powder reacts with the alkali solution in the saline-alkali pool 9 to generate aluminum salt. The mixed solution containing alkali solution and aluminum salt obtained in the saline-alkali pool 9 is discharged from the first liquid discharge port 13; while the de-ironization mask powder containing polar organic matter and non-polar organic matter cannot react, and will float on the liquid surface, and will be driven to the powder outlet 15 by the pushing rod 12 for discharge, and what is discharged from the powder outlet 15 is the dealuminated mask powder containing polar organic matter and non-polar organic matter.

[0078] In some embodiments, the alkali solution may be a sodium hydroxide solution and / or a potassium hydroxide solution. Furthermore, the alkali solution can dissolve esters in the mask. If the mask contains lipids, a mixed solution containing alkali solution, aluminum salt, and esters will be discharged from the first liquid discharge port 13.

[0079] In one embodiment, step (4) removes the polar organic matter in the dealuminated mask powder to obtain a non-polar organic powder, comprising: mixing the dealuminated mask powder with a polar solvent, dissolving the polar organic matter in the dealuminated mask powder in the polar solvent, and suspending the non-polar organic matter in the solution, and then filtering under reduced pressure to obtain a solid phase product that is a non-polar organic powder. More specifically, the dealuminated mask powder is discharged from the powder outlet 15 and enters the dissolution tank 16, the polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The obtained layered mixture is discharged from the second liquid discharge port 18 and enters the filtration device 20, and is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder.

[0080] In some embodiments, the polar solvent may be ethylene glycol and / or dimethyl sulfoxide.

[0081] In one embodiment, step (5) separates the polyethylene from the non-polar organic powder to obtain polypropylene, and the process includes: heating the non-polar organic powder to volatilize the surface of the non-polar organic powder, and then mixing the heated non-polar organic powder with a wetting agent aqueous solution, wherein the polyethylene sinks under the action of the wetting agent aqueous solution and the polypropylene floats, and the polypropylene is obtained after separation. Specifically, the non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through the conveying pipe 27, and the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent and other solutions added in the above steps) is volatilized by heating. The heated non-polar organic powder enters the flotation tank 22 from the input port 23, and the polyethylene sinks under the action of the wetting agent aqueous solution, and the polypropylene floats due to its own hydrophobicity. The mixture of polyethylene and the wetting agent aqueous solution is discharged from the third drain port 26, and the polypropylene collected in the flotation tank 22 is polypropylene with higher purity, thereby obtaining polypropylene.

[0082] In the present invention, the aqueous wetting agent solution is an aqueous solution of calcium lignin sulfonate and / or an aqueous solution of sodium lauryl sulfate. To improve flotation efficiency and enable more efficient separation of polypropylene and polyethylene, the aqueous wetting agent solution is an aqueous solution of calcium lignin sulfonate. In some embodiments, the mass fraction of the aqueous wetting agent solution is 0.2-0.5%.

[0083] The advantages of the mask recycling system and method provided by the present invention are: 1. Fine separation: The use of magnetic separation technology can effectively separate metal components such as iron powder from the mask material, thereby improving the purity of the recycled material and enabling different materials to be better reused separately. 2. Organic solvent removal: By adding polar organic solvents to remove polar organic impurities in the mask powder, compared with traditional physical screening or simple cleaning, it can remove organic impurities more deeply, improve the quality of recycled polypropylene, and broaden its scope of reuse. 3. Targeted wetting flotation: In the flotation unit, a wetting agent aqueous solution, especially a calcium lignin sulfonate aqueous solution, is used for flotation, making the flotation process more efficient and more conducive to the separation of polypropylene and polyethylene, ensuring the quality of the recovered polypropylene and polyethylene. 4. Multiple reuse: The present invention recycles polypropylene and polyethylene separately through a multi-step process, which can be used in construction sites, plastic manufacturing, textile products, etc., to create economic value; moreover, the recycled polypropylene and polyethylene can be reused in multiple ways. Specifically, the recycled polypropylene can be used for melt spinning, and the recycled polyethylene can be used for melt regeneration and recycling, giving full play to the characteristics of different materials, realizing efficient recycling of resources, and improving the economic value and environmental benefits of the entire recycling.

[0084] The present invention will be described in detail below through examples, but the scope of protection of the present invention is not limited thereto. In the following examples, unless otherwise specified, the raw materials used are all commercially available products commonly found in the art.

[0085] Example 1

[0086] In this embodiment, the alkali solution is a sodium hydroxide solution with a concentration of 11 mol / L; the polar solvent is ethylene glycol; and the wetting agent aqueous solution is a calcium lignin sulfonate aqueous solution with a mass fraction of 0.3%.

[0087] like Figure 1 As shown, the mask recycling system includes a crushing unit 40, an iron powder separation unit 50, a salt and alkali pool unit 60, a non-polar substance recovery unit 70 and a dry flotation unit 80;

[0088] The pulverizing unit 40 includes a first blower 1, a pulverizing device, a second blower 5 and a collecting device 6, which are arranged in sequence from top to bottom. The pulverizing device includes a shell 28 and an inner cavity 29. The inner cavity is provided with a cross-cutting pulverizer 2 and a shearing pulverizer 3 from top to bottom. The top of the pulverizing device has an air inlet 30. The second blower 5 is located on one side of the bottom of the pulverizing device. The other side of the bottom of the pulverizing device is provided with an air outlet 4 opposite to the second blower 5. The mask is blown out from the blast inlet 30 under the action of the wind force of the first blower 1. After entering the pulverizing device, it is pulverized in turn by the cross-cutting pulverizer 2 and the shearing pulverizer 3 to obtain a pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out under the action of the transverse wind force applied by the second blower 5 to obtain small-particle mask powder with a particle size of ≤0.5 mm. The small-particle mask powder enters the iron powder separation unit 50 through the air outlet 4. The large-particle mask powder with a particle size of >0.5 mm that is not completely pulverized after being pulverized by the cross-cutting pulverizer 2 and the shearing pulverizer 3 is collected in the collecting device 6 and pulverized again;

[0089] The iron powder separation unit 50 includes a conveyor belt 8 and an electromagnet 7 arranged on the upper part of the conveyor belt 8. The conveyor belt 8 can be located directly below the air blast outlet 4. The small-particle mask powder from the crushing unit 40 falls onto the conveyor belt 8 through the air blast outlet 4. During the transportation process of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8. The iron powder is separated under the attraction of magnetic force and adsorbed on the electromagnet 7. What remains on the conveyor belt 8 is the mask powder after the iron is removed, and finally separated iron powder and deironized mask powder are obtained;

[0090] The saline-alkali pool unit 60 includes a saline-alkali pool 9, which is a three-chamber saline-alkali pool. The first-chamber saline-alkali pool is provided with a powder inlet 11, a powder discharge port 14 is provided between the first-chamber saline-alkali pool and the second-chamber saline-alkali pool, and between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool, and the three-chamber saline-alkali pool is provided with a powder outlet 15. The first-chamber saline-alkali pool, the second-chamber saline-alkali pool and the third-chamber saline-alkali pool are all provided with a first liquid addition port 10, a push rod 12 and a first liquid discharge port 13. The de-iron mask powder on the conveyor belt 8 in the iron powder separation unit 50 is discharged from the first-chamber saline-alkali pool. After the powder inlet 11 enters the first chamber of the saline-alkali pool, the aluminum in the deironing mask powder reacts with the alkali solution in the first chamber of the saline-alkali pool to generate aluminum salt. The mixed solution containing the alkali solution and the aluminum salt is discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the first chamber of the saline-alkali pool to the powder discharge port 14 between the first chamber of the saline-alkali pool and the second chamber of the saline-alkali pool and enter the second chamber of the saline-alkali pool; the mixed solution containing polar organic matter and non-polar organic matter will be discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The aluminum remaining in the deironing mask powder reacts with the alkali solution in the second chamber saline alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first liquid discharge port 13 in the second chamber saline alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the second chamber saline alkali pool to the powder discharge port 14 between the second chamber saline alkali pool and the third chamber saline alkali pool, and enter the third chamber saline alkali pool; the aluminum remaining in the deironing mask powder containing polar organic matter and non-polar organic matter Aluminum reacts with the alkali liquor in the three-chamber saline-alkali pool to generate aluminum salt, and the aluminum-containing solution containing the alkali liquor and the aluminum salt is discharged from the first liquid discharge port 13 in the three-chamber saline-alkali pool, while the de-ironization mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It is driven to the powder outlet 15 of the three-chamber saline-alkali pool by the pushing rod 12 in the three-chamber saline-alkali pool. At this time, the dealuminated mask powder (the purity of polar organic matter and non-polar organic matter is higher) is discharged from the powder outlet 15 and enters the non-polar substance recovery unit 70;

[0091] The non-polar substance recovery unit 70 includes a dissolution tank 16, a decompression device 19 and a filtering device 20. The dissolution tank 16 is provided with a second liquid adding port 17 and a second liquid drain 18. The second liquid adding port 17 is used to add a polar solvent to the dissolution tank 16. The dealuminated mask powder from the saline-alkali tank unit 6 is discharged from the powder outlet 15 and enters the dissolution tank 16. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The obtained layered mixture is discharged from the second liquid drain port 18 and enters the filtering device 20. It is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder.

[0092] The dry flotation unit 80 includes a heating device 21 and a flotation tank 22. The flotation tank 22 includes an input port 23, a third liquid addition port 24, and a third liquid discharge port 26. The third liquid addition port 24 is used to add a wetting agent aqueous solution to the flotation tank 22. The non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through a conveying pipe 27. The non-polar organic powder is heated to volatilize the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent, etc. added in the above steps). The heated non-polar organic powder enters the flotation tank 22 through the input port 23. Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats due to its own hydrophobicity. The polyethylene solution containing polyethylene and wetting agent is discharged from the third liquid discharge port 26. The polypropylene collected in the flotation tank 22 is high-purity polypropylene, thereby obtaining polypropylene.

[0093] In this embodiment, the content of the obtained iron powder is 99.7%; the content of aluminum in the aluminum-containing solution is 32%; the content of polypropylene is 98.5%; and the content of polyethylene in the polyethylene solution is 91%.

[0094] Example 2

[0095] In this embodiment, the alkali solution is a sodium hydroxide solution with a concentration of 7 mol / L; the polar solvent is ethylene glycol; and the wetting agent aqueous solution is a calcium lignin sulfonate aqueous solution with a mass fraction of 0.3%.

[0096] like Figure 1 As shown, the mask recycling system includes a crushing unit 40, an iron powder separation unit 50, a salt and alkali pool unit 60, a non-polar substance recovery unit 70 and a dry flotation unit 80;

[0097] The pulverizing unit 40 includes a first blower 1, a pulverizing device, a second blower 5 and a collecting device 6, which are arranged in sequence from top to bottom. The pulverizing device includes a shell 28 and an inner cavity 29. The inner cavity is provided with a cross-cutting pulverizer 2 and a shearing pulverizer 3 from top to bottom. The top of the pulverizing device has an air inlet 30. The second blower 5 is located on one side of the bottom of the pulverizing device. The other side of the bottom of the pulverizing device is provided with an air outlet 4 opposite to the second blower 5. The mask is blown out from the blast inlet 30 under the action of the wind force of the first blower 1. After entering the pulverizing device, it is pulverized in turn by the cross-cutting pulverizer 2 and the shearing pulverizer 3 to obtain a pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out under the action of the transverse wind force applied by the second blower 5 to obtain small-particle mask powder with a particle size of ≤0.5 mm. The small-particle mask powder enters the iron powder separation unit 50 through the air outlet 4. The large-particle mask powder with a particle size of >0.5 mm that is not completely pulverized after being pulverized by the cross-cutting pulverizer 2 and the shearing pulverizer 3 is collected in the collecting device 6 and pulverized again;

[0098] The iron powder separation unit 50 includes a conveyor belt 8 and an electromagnet 7 arranged on the upper part of the conveyor belt 8. The conveyor belt 8 can be located directly below the air blast outlet 4. The small-particle mask powder from the crushing unit 40 falls onto the conveyor belt 8 through the air blast outlet 4. During the transportation process of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8. The iron powder is separated under the attraction of magnetic force and adsorbed on the electromagnet 7. What remains on the conveyor belt 8 is the mask powder after the iron is removed, and finally separated iron powder and deironized mask powder are obtained;

[0099] The saline-alkali pool unit 60 includes a saline-alkali pool 9, which is a three-chamber saline-alkali pool. The first-chamber saline-alkali pool is provided with a powder inlet 11, a powder discharge port 14 is provided between the first-chamber saline-alkali pool and the second-chamber saline-alkali pool, and between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool, and the three-chamber saline-alkali pool is provided with a powder outlet 15. The first-chamber saline-alkali pool, the second-chamber saline-alkali pool and the third-chamber saline-alkali pool are all provided with a first liquid addition port 10, a push rod 12 and a first liquid discharge port 13. The de-iron mask powder on the conveyor belt 8 in the iron powder separation unit 50 is discharged from the first-chamber saline-alkali pool. After the powder inlet 11 enters the first chamber of the saline-alkali pool, the aluminum in the deironing mask powder reacts with the alkali solution in the first chamber of the saline-alkali pool to generate aluminum salt. The mixed solution containing the alkali solution and the aluminum salt is discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the first chamber of the saline-alkali pool to the powder discharge port 14 between the first chamber of the saline-alkali pool and the second chamber of the saline-alkali pool and enter the second chamber of the saline-alkali pool; the mixed solution containing polar organic matter and non-polar organic matter will be discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The aluminum remaining in the deironing mask powder reacts with the alkali solution in the second chamber saline alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first liquid discharge port 13 in the second chamber saline alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the second chamber saline alkali pool to the powder discharge port 14 between the second chamber saline alkali pool and the third chamber saline alkali pool, and enter the third chamber saline alkali pool; the aluminum remaining in the deironing mask powder containing polar organic matter and non-polar organic matter Aluminum reacts with the alkali liquor in the three-chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing the alkali liquor and the aluminum salt is discharged from the first liquid discharge port 13 in the three-chamber saline-alkali pool, while the de-ironization mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It is driven to the powder outlet 15 of the three-chamber saline-alkali pool by the pushing rod 12 in the three-chamber saline-alkali pool. At this time, the dealuminated mask powder (the purity of polar organic matter and non-polar organic matter is higher) is discharged from the powder outlet 15 and enters the non-polar substance recovery unit 70;

[0100] The non-polar substance recovery unit 70 includes a dissolution tank 16, a decompression device 19 and a filtering device 20. The dissolution tank 16 is provided with a second liquid adding port 17 and a second liquid drain 18. The second liquid adding port 17 is used to add a polar solvent to the dissolution tank 16. The dealuminated mask powder from the saline-alkali tank unit 6 is discharged from the powder outlet 15 and enters the dissolution tank 16. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The obtained layered mixture is discharged from the second liquid drain port 18 and enters the filtering device 20. It is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder.

[0101] The dry flotation unit 80 includes a heating device 21 and a flotation tank 22. The flotation tank 22 includes an input port 23, a third liquid addition port 24, and a third liquid discharge port 26. The third liquid addition port 24 is used to add a wetting agent aqueous solution to the flotation tank 22. The non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through a conveying pipe 27. The non-polar organic powder is heated to volatilize the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent, etc. added in the above steps). The heated non-polar organic powder enters the flotation tank 22 through the input port 23. Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats due to its own hydrophobicity. The mixture of polyethylene and wetting agent is discharged from the third liquid discharge port 26. The polypropylene collected in the flotation tank 22 is high-purity polypropylene, thereby obtaining polypropylene.

[0102] In this embodiment, the content of the obtained iron powder is 99.7%; the content of aluminum in the aluminum-containing solution is 30%; the content of polypropylene is 95%; and the content of polyethylene in the polyethylene solution is 87%.

[0103] Example 3

[0104] In this embodiment, the alkali solution is a sodium hydroxide solution with a concentration of 11 mol / / L; the polar solvent is ethanol; and the wetting agent aqueous solution is a calcium lignin sulfonate aqueous solution with a mass fraction of 0.3%.

[0105] like Figure 1 As shown, the mask recycling system includes a crushing unit 40, an iron powder separation unit 50, a salt and alkali pool unit 60, a non-polar substance recovery unit 70 and a dry flotation unit 80;

[0106] The pulverizing unit 40 includes a first blower 1, a pulverizing device, a second blower 5 and a collecting device 6, which are arranged in sequence from top to bottom. The pulverizing device includes a shell 28 and an inner cavity 29. The inner cavity is provided with a cross-cutting pulverizer 2 and a shearing pulverizer 3 from top to bottom. The top of the pulverizing device has an air inlet 30. The second blower 5 is located on one side of the bottom of the pulverizing device. The other side of the bottom of the pulverizing device is provided with an air outlet 4 opposite to the second blower 5. The mask is blown out from the blast inlet 30 under the action of the wind force of the first blower 1. After entering the pulverizing device, it is pulverized in turn by the cross-cutting pulverizer 2 and the shearing pulverizer 3 to obtain a pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out under the action of the transverse wind force applied by the second blower 5 to obtain small-particle mask powder with a particle size of ≤0.5 mm. The small-particle mask powder enters the iron powder separation unit 50 through the air outlet 4. The large-particle mask powder with a particle size of >0.5 mm that is not completely pulverized after being pulverized by the cross-cutting pulverizer 2 and the shearing pulverizer 3 is collected in the collecting device 6 and pulverized again;

[0107] The iron powder separation unit 50 includes a conveyor belt 8 and an electromagnet 7 arranged on the upper part of the conveyor belt 8. The conveyor belt 8 can be located directly below the air blast outlet 4. The small-particle mask powder from the crushing unit 40 falls onto the conveyor belt 8 through the air blast outlet 4. During the transportation process of the conveyor belt 8, the iron in the mask powder is adsorbed by the electromagnet 7 on the upper part of the conveyor belt 8. The iron powder is separated under the attraction of magnetic force and adsorbed on the electromagnet 7. What remains on the conveyor belt 8 is the mask powder after the iron is removed, and finally separated iron powder and deironized mask powder are obtained;

[0108] The saline-alkali pool unit 60 includes a saline-alkali pool 9, which is a three-chamber saline-alkali pool. The first-chamber saline-alkali pool is provided with a powder inlet 11, a powder discharge port 14 is provided between the first-chamber saline-alkali pool and the second-chamber saline-alkali pool, and between the second-chamber saline-alkali pool and the third-chamber saline-alkali pool, and the three-chamber saline-alkali pool is provided with a powder outlet 15. The first-chamber saline-alkali pool, the second-chamber saline-alkali pool and the third-chamber saline-alkali pool are all provided with a first liquid addition port 10, a push rod 12 and a first liquid discharge port 13. The de-iron mask powder on the conveyor belt 8 in the iron powder separation unit 50 is discharged from the first-chamber saline-alkali pool. After the powder inlet 11 enters the first chamber of the saline-alkali pool, the aluminum in the deironing mask powder reacts with the alkali solution in the first chamber of the saline-alkali pool to generate aluminum salt. The mixed solution containing the alkali solution and the aluminum salt is discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the first chamber of the saline-alkali pool to the powder discharge port 14 between the first chamber of the saline-alkali pool and the second chamber of the saline-alkali pool and enter the second chamber of the saline-alkali pool; the mixed solution containing polar organic matter and non-polar organic matter will be discharged from the first liquid discharge port 13 in the first chamber of the saline-alkali pool. The aluminum remaining in the deironing mask powder reacts with the alkali solution in the second chamber saline alkali pool to generate aluminum salt, and the mixed solution containing alkali solution and aluminum salt is discharged from the first liquid discharge port 13 in the second chamber saline alkali pool, while the deironing mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It will be driven by the pushing rod 12 in the second chamber saline alkali pool to the powder discharge port 14 between the second chamber saline alkali pool and the third chamber saline alkali pool, and enter the third chamber saline alkali pool; the aluminum remaining in the deironing mask powder containing polar organic matter and non-polar organic matter Aluminum reacts with the alkali liquor in the three-chamber saline-alkali pool to generate aluminum salt, and the mixed solution containing the alkali liquor and the aluminum salt is discharged from the first liquid discharge port 13 in the three-chamber saline-alkali pool, while the de-ironization mask powder containing polar organic matter and non-polar organic matter cannot react and will float on the liquid surface. It is driven to the powder outlet 15 of the three-chamber saline-alkali pool by the pushing rod 12 in the three-chamber saline-alkali pool. At this time, the dealuminated mask powder (the purity of polar organic matter and non-polar organic matter is higher) is discharged from the powder outlet 15 and enters the non-polar substance recovery unit 70;

[0109] The non-polar substance recovery unit 70 includes a dissolution tank 16, a decompression device 19 and a filtering device 20. The dissolution tank 16 is provided with a second liquid adding port 17 and a second liquid drain 18. The second liquid adding port 17 is used to add a polar solvent to the dissolution tank 16. The dealuminated mask powder from the saline-alkali tank unit 6 is discharged from the powder outlet 15 and enters the dissolution tank 16. The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank 16, and the non-polar organic matter is suspended in the solution. The obtained layered mixture is discharged from the second liquid drain port 18 and enters the filtering device 20. It is filtered under the action of the decompression device 19 to obtain a mixed liquid containing polar organic matter and a solid phase product, respectively. The obtained solid phase product is a non-polar organic powder.

[0110] The dry flotation unit 80 includes a heating device 21 and a flotation tank 22. The flotation tank 22 includes an input port 23, a third liquid addition port 24, and a third liquid discharge port 26. The third liquid addition port 24 is used to add a wetting agent aqueous solution to the flotation tank 22. The non-polar organic powder from the non-polar substance recovery unit 70 enters the heating device 21 through a conveying pipe 27. The non-polar organic powder is heated to volatilize the solution on the surface of the non-polar organic powder (including the alkali solution, polar solvent, etc. added in the above steps). The heated non-polar organic powder enters the flotation tank 22 through the input port 23. Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats due to its own hydrophobicity. The mixture of polyethylene and wetting agent is discharged from the third liquid discharge port 26. The polypropylene collected in the flotation tank 22 is high-purity polypropylene, thereby obtaining polypropylene.

[0111] In this embodiment, the content of the obtained iron powder is 99.7%; the content of aluminum in the aluminum-containing solution is 32%; the content of polypropylene is 94.5%; and the content of polyethylene in the polyethylene solution is 88.5%.

[0112] Example 4

[0113] The method of Example 1 was followed, except that the alkali solution was a sodium hydroxide solution with a concentration of 16 mol / L.

[0114] In this embodiment, the content of the obtained iron powder is 99.7%; the content of aluminum in the aluminum-containing solution is 31%; the content of polypropylene is 92%; and the content of polyethylene in the polyethylene solution is 89%.

[0115] It can be seen from the above examples that the method described in the present invention is used to recycle various components in masks, and iron powder, aluminum-containing solution, polypropylene and polyethylene solution with high content can be obtained. The recycled materials can be reused in multiple ways, and efficient recycling of resources can be achieved, thereby improving the economic value and environmental benefits of the entire recycling process.

[0116] It should be understood that parts not elaborated in detail in this specification belong to the prior art.

[0117] The preferred embodiments of the present invention have been described in detail above, but the present invention is not limited thereto. Within the technical concept of the present invention, various simple variations of the technical solution of the present invention may be made, including combining the various technical features in any other appropriate manner. These simple variations and combinations should also be regarded as disclosed in the present invention and fall within the scope of protection of the present invention.

Claims

1. A mask recycling system, characterized in that: The mask recycling system includes: A crushing unit (40) is used to crush and screen the mask to obtain mask powder containing iron, aluminum, polar organic matter and non-polar organic matter; An iron powder separation unit (50) is used to remove iron from the mask powder to obtain deironized mask powder and iron powder; a salt-alkali pool unit (60) for removing aluminum from the de-ironized powder to obtain dealuminated mask powder; a non-polar substance recovery unit (70) for separating polar organic matter from the dealuminated powder to obtain non-polar organic powder containing polyethylene and polypropylene; The drying flotation unit (80) is used to separate polyethylene from the non-polar organic powder to obtain polypropylene.

2. The mask recycling system according to claim 1, characterized in that: The pulverizing unit (40) comprises a first blower (1), a pulverizing device, a second blower (5) and a collecting device (6) which are arranged in sequence from top to bottom. The pulverizing device comprises an outer shell (28) and an inner cavity (29). A cross-cutting pulverizer (2) and a shearing pulverizer (3) are arranged in sequence from top to bottom in the inner cavity. The top of the pulverizing device has an air inlet (30). The second blower (5) is located on one side of the bottom of the pulverizing device. An air outlet (4) opposite to the second blower (5) is provided on the other side of the bottom of the pulverizing device. The mask enters the pulverizing device from the blast inlet (30) under the action of the wind force of the first blower (1), and is pulverized in turn by the cross-cutting pulverizer (2) and the shearing pulverizer (3) to obtain pulverized mask material with a particle size of 3-5 mm. The pulverized mask material is screened out into small-particle mask powder with a particle size of ≤0.5 mm under the action of the transverse wind force applied by the second blower (5). The small-particle mask powder enters the iron powder separation unit (50) through the blast outlet (4); Alternatively, the collecting device (6) is used to collect large-particle mask powder with a particle size greater than 0.5 mm screened out under the action of the lateral wind force applied by the second blower (5).

3. The mask recycling system according to claim 1 or 2, characterized in that: The iron powder separation unit (50) includes a conveyor belt (8) and an electromagnet (7) arranged on the upper part of the conveyor belt (8); The mask powder from the crushing unit (40) reaches the conveyor belt (8) through the air blast outlet (4), and the iron in the mask powder is adsorbed by the electromagnet (7) to obtain iron powder and de-ironized mask powder.

4. The mask recycling system according to claim 1, characterized in that: The salt-alkali pool unit (60) comprises a salt-alkali pool (9), wherein the salt-alkali pool (9) has a powder inlet (11), a first liquid addition port (10), a first liquid discharge port (13) and a powder outlet (15), wherein a push rod (12) is provided at the powder inlet (11), and the first liquid addition port (10) is used to add alkali solution into the salt-alkali pool (9); The de-iron mask powder from the iron powder separation unit (50) enters the saline-alkali pool (9) from the powder inlet (11), and the aluminum in the de-iron mask powder reacts with the alkali solution in the saline-alkali pool (9), and the obtained mixed solution is discharged from the first liquid discharge port (13); the de-iron mask powder that cannot react floats on the liquid surface and is driven to the powder discharge port (15) by the pushing rod (12) to be discharged, thereby obtaining the dealuminated mask powder; Alternatively, the saline-alkali pool (9) is a multi-chamber saline-alkali pool, and a powder discharge port (14) is provided between two adjacent saline-alkali pools. Under the action of the pushing rod (12), the deironing mask powder floating on the liquid surface enters the saline-alkali pool of the next chamber from the upper chamber through the powder discharge port (14) and is finally discharged from the powder outlet (15).

5. The mask recycling system according to claim 1, characterized in that: The non-polar substance recovery unit (70) comprises a dissolution tank (16), a pressure reducing device (19) and a filtering device (20); the dissolution tank (16) is provided with a second liquid adding port (17) and a second liquid draining port (18); the second liquid adding port (17) is used to add a polar solvent to the dissolution tank (16); The dealuminated mask powder from the saline-alkali pool unit (60) is discharged from the powder outlet (15) and enters the dissolution tank (16). The polar organic matter in the dealuminated mask powder is dissolved in the polar solvent in the dissolution tank (16), and the non-polar organic matter is suspended in the solution. The resulting mixture is discharged from the second liquid discharge port (18) and enters the filtering device (20). It is filtered under the action of the decompression device (19), and the obtained solid phase product is non-polar organic powder.

6. The mask recycling system according to claim 1, characterized in that: The dry flotation unit (80) comprises a heating device (21) and a flotation tank (22), wherein the flotation tank (22) comprises an input port (23), a third liquid addition port (24) and a third liquid discharge port (26), wherein the third liquid addition port (24) is used to add a wetting agent aqueous solution into the flotation tank (22); The non-polar organic powder from the non-polar substance recovery unit (70) enters the heating device (21) through a conveying pipe (27) and is heated to volatilize the solution on the surface of the non-polar organic powder. The heated non-polar organic powder enters the flotation tank (22) from the input port (23). Polyethylene sinks under the action of the wetting agent aqueous solution, while polypropylene floats. The mixture of polyethylene and the wetting agent is discharged from the third liquid discharge port (26) to obtain polypropylene. Alternatively, a fan (25) is provided in the flotation tank (22) to accelerate the floating of the polypropylene.

7. A mask recycling method, which is implemented using the mask recycling system according to any one of claims 1 to 6, characterized in that: The mask recycling method includes: The mask is crushed and screened to obtain mask powder, wherein the mask powder contains iron, aluminum, polar organic matter and non-polar organic matter; Separating the iron from the mask powder to obtain deironized mask powder and iron powder; Separate and remove aluminum from the de-ironized powder to obtain dealuminated mask powder; Removing polar organic matter from the dealuminated mask powder to obtain non-polar organic powder, wherein the non-polar organic powder contains polyethylene and polypropylene; The polyethylene in the non-polar organic powder is separated to obtain polypropylene.

8. The method according to claim 7, characterized in that The process of separating and removing aluminum from the de-ironized powder to obtain the dealuminated mask powder includes: reacting the aluminum in the de-ironized mask powder with an alkali solution; the de-ironized mask powder that cannot react floats on the liquid surface and is discharged to obtain the dealuminated mask powder; Alternatively, the alkali solution is sodium hydroxide solution and / or potassium hydroxide solution.

9. The method according to claim 7, characterized in that The process of removing polar organic matter from dealuminated mask powder to obtain non-polar organic matter powder includes: mixing the dealuminated mask powder with a polar solvent, dissolving the polar organic matter in the dealuminated mask powder in the polar solvent, suspending the non-polar organic matter in the solution, and then filtering under reduced pressure to obtain a solid phase product as non-polar organic matter powder; Alternatively, the polar solvent is ethylene glycol and / or dimethyl sulfoxide.

10. The method according to claim 7, characterized in that The process of separating polyethylene from non-polar organic powder to obtain polypropylene includes: heating the non-polar organic powder to volatilize the surface of the non-polar organic powder, then mixing the heated non-polar organic powder with a wetting agent aqueous solution, causing the polyethylene to sink under the action of the wetting agent aqueous solution and the polypropylene to float, thereby obtaining the polypropylene after separation; Alternatively, the wetting agent aqueous solution is a calcium lignin sulfonate aqueous solution and / or a sodium lauryl sulfate aqueous solution.

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