Pretreatment process and device for waste plastic recovery

Abstract

The invention belongs to the technical field of plastic recovery, and particularly relates to a pretreatment process and device for waste plastic recovery. According to the pretreatment process for waste plastic recovery, cleaned plastic is cooled at the first cooling temperature T1; carrying out primary crushing on the cooled plastic; sorting the primarily crushed plastics into a first type of plastics and a second type of plastics; according to the plastic crushing device, the first type of plastic is subjected to secondary crushing, the second type of plastic is cooled at the second cooling temperature T2, the cooled second type of plastic is subjected to secondary crushing, and the second cooling temperature T2 is smaller than the first cooling temperature T1, so that the crushing uniformity of the plastic is improved after two times of cooling and crushing at different temperatures.

Description

Technical Field

[0001] The invention belongs to the technical field of plastic recycling, and in particular relates to a pretreatment process and device for recycling waste plastics. Background Art

[0002] The traditional way to deal with waste plastics is landfill and incineration. These two treatment methods will greatly pollute the land and the atmosphere. However, collecting and classifying different plastics and granulating them for use as recycled plastics is both environmentally friendly and can be used for secondary use of waste plastics. In the prior art, Chinese patent CN104672708B discloses a polyvinyl chloride composite material for recycling waste plastics and a preparation method thereof. The method first removes non-plastic impurities in waste automobile plastic products, and then crushes the sorted plastics. However, the plastics are not crushed uniformly. Some plastics have good crushing effects, while some plastics have poor crushing effects. The plastics with poor crushing effects usually appear in the form of flakes or films. Summary of the invention

[0003] Based on this, it is necessary to provide a pretreatment process for recycling waste plastics to solve the problem of poor uniformity in crushing plastics in the plastic recycling process in the prior art, and also provide a pretreatment device for recycling waste plastics to solve the problem of poor uniformity in crushing plastics in the pretreatment device in the prior art.

[0004] The above purpose is achieved through the following technical solutions: A pretreatment process for recycling waste plastics comprises the following steps: S100: Cooling the cleaned plastic at a first cooling temperature T1; S200: Initially crush the cooled plastic; S300: sort the plastics after primary crushing into first-class plastics and second-class plastics; S400: performing secondary crushing on the first type of plastic, cooling the second type of plastic at a second cooling temperature T2, and performing secondary crushing on the cooled second type of plastic, wherein the second cooling temperature T2 is lower than the first cooling temperature T1.

[0005] Furthermore, in step S100, the plastic is washed, dehydrated, and then cooled.

[0006] Furthermore, in step S400, the mass M1 of the sorted first type of plastic and the mass M2 of the sorted second type of plastic are measured, and the cooling temperature and the speed of conveying the second type of plastic are adjusted according to the ratio K between the mass M1 of the first type of plastic and the total mass M1+M2 of the plastic.

[0007] Further, when the ratio K is less than or equal to the first setting parameter C1, the first cooling temperature T1 and the second cooling temperature T2 are lowered, and the speed of conveying the second type of plastic in step S400 is increased.

[0008] Further, when the ratio K is greater than the first setting parameter C1 and less than the second setting parameter C2, the second cooling temperature T2 is lowered, and the speed of conveying the second type of plastic in step S400 is increased.

[0009] Further, when the ratio K is greater than or equal to the second setting parameter C2 and less than or equal to the third setting parameter C3, the second cooling temperature T2 is increased, and the speed of conveying the second type of plastic in step S400 is reduced.

[0010] Further, when the ratio K is greater than the third setting parameter C3, cooling of the second type of plastic is stopped.

[0011] Furthermore, in step S300, the plastic after the primary crushing is sorted into the first type of plastic and the second type of plastic by blowing.

[0012] The beneficial effects of the present invention are as follows: the pretreatment process for recycling waste plastics of the present invention first cleans the plastics, removes impurities on the surface of the plastics by cleaning, then cools the cleaned plastics at a first cooling temperature T1 to make the plastics brittle, and then performs a primary crushing on the plastics. Since different plastics have different plasticities at the same temperature, there will be uneven crushing during the primary crushing, resulting in some plastics being initially crushed into granules and some plastics being films or sheets that are not easy to crush. Then, the plastics after the primary crushing are sorted into a first type of plastic and a second type of plastic, wherein the first type of plastic refers to granular plastics and the second type of plastic refers to films or sheets. Then, the first type of plastic is crushed for the second time, and the second type of plastic is cooled at a second cooling temperature T2. Since the second cooling temperature T2 is lower than the first cooling temperature, the second type of plastic can be made more brittle and more convenient to crush, thereby improving the uniformity of the crushing of the plastics.

[0013] A pretreatment device for recycling waste plastics is used to implement the above-mentioned pretreatment process for recycling waste plastics. The pretreatment device for recycling waste plastics includes a first cooling module, a first crushing module, a sorting module, a second cooling module, a second crushing module and a control module; the first cooling module is used to cool the cleaned plastic; the first crushing module is used to crush the plastic discharged from the first cooling module; the sorting module is used to sort the plastic after the initial crushing into a first type of plastic and a second type of plastic, the second cooling module is used to cool the second type of plastic, the second crushing module is used to crush the first type of plastic and the cooled second type of plastic, and the control module is used to adjust the cooling temperature of the first cooling module and the second cooling module and the speed of conveying the second type of plastic according to the ratio between the mass of the first type of plastic and the total mass of the plastic.

[0014] Furthermore, the sorting module is a sorting fan.

[0015] The beneficial effect of the present invention is as follows: the pretreatment device for recycling waste plastics of the present invention first uses the first cooling module to cool the plastic to make the plastic brittle, and then uses the first crushing module to perform initial crushing on the plastic. Since different plastics have different plasticities at the same temperature, there will be uneven crushing during the initial crushing, resulting in some plastics being initially crushed into granules, and some plastics being film-like or sheet-like types that are not easy to crush. Then, the sorting module is used to sort the initially crushed plastics into first-category plastics and second-category plastics, wherein the first-category plastics refer to granular plastics, and the second-category plastics refer to film-like or sheet-like types of plastics. Then, the second crushing module is used to perform secondary crushing on the first-category plastics, and the second-category plastics are cooled by the second cooling module to make the second-category plastics more brittle and more convenient to crush by the second crushing module, thereby improving the uniformity of the plastic crushing. BRIEF DESCRIPTION OF THE DRAWINGS

[0016] Figure 1 A flowchart of an embodiment of a pretreatment process for recycling waste plastics of the present invention; Figure 2 This is a schematic structural diagram of an embodiment of a pretreatment device for recycling waste plastics of the present invention.

[0017] in: 100, frame; 210, first conveyor belt; 220, first cooling chamber; 230, first crushing chamber; 240, sorting fan; 310, second conveyor belt; 320, second cooling chamber; 330, third conveyor belt; 340, scraper; 350, second crushing chamber. DETAILED DESCRIPTION

[0018] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below through embodiments and in conjunction with the accompanying drawings. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0019] The serial numbers assigned to the components herein, such as "first", "second", etc., are only used to distinguish the objects described and do not have any order or technical meaning. The "connection" and "coupling" mentioned in this application, unless otherwise specified, include direct and indirect connections (couplings). In the description of the present invention, it should be understood that the orientation or position relationship indicated by the terms "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside", "clockwise", "counterclockwise", etc. are based on the orientation or position relationship shown in the accompanying drawings, which is only for the convenience of describing the present invention and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore cannot be understood as a limitation to the present invention.

[0020] In the present invention, unless otherwise clearly specified and limited, a first feature being "above" or "below" a second feature may mean that the first and second features are in direct contact, or the first and second features are in indirect contact through an intermediate medium. Moreover, a first feature being "above", "above" or "above" a second feature may mean that the first feature is directly above or obliquely above the second feature, or simply means that the first feature is higher in level than the second feature. A first feature being "below", "below" or "below" a second feature may mean that the first feature is directly below or obliquely below the second feature, or simply means that the first feature is lower in level than the second feature.

[0021] Refer to the following Figure 1 , describing a pretreatment process for recycling waste plastics provided in an embodiment of the first aspect of the present invention.

[0022] The pretreatment process for recycling waste plastics in this embodiment includes the following steps: S100: Cooling the cleaned plastic at a first cooling temperature T1; S200: Initially crush the cooled plastic; S300: sort the plastics after primary crushing into first-class plastics and second-class plastics; S400: performing secondary crushing on the first type of plastic, cooling the second type of plastic at a second cooling temperature T2, and performing secondary crushing on the cooled second type of plastic, wherein the second cooling temperature T2 is lower than the first cooling temperature T1.

[0023] In the pretreatment process for recycling waste plastics of the present embodiment, the plastics are first cleaned to remove impurities on the surface of the plastics, and then the cleaned plastics are cooled at a first cooling temperature T1 to make the plastics brittle, and then the plastics are initially crushed. Since different plastics have different plasticities at the same temperature, there will be uneven crushing during the initial crushing, resulting in some plastics being initially crushed into granules and some plastics being film-like or sheet-like types that are not easy to crush. Then, the initially crushed plastics are sorted into a first type of plastic and a second type of plastic, wherein the first type of plastic refers to granular plastics and the second type of plastic refers to film-like or sheet-like types of plastics. Then, the first type of plastic is crushed for the second time, and the second type of plastic is cooled at a second cooling temperature T2. Since the second cooling temperature T2 is lower than the first cooling temperature, the second type of plastic can be made more brittle and easier to crush, thereby improving the uniformity of the crushing of the plastics.

[0024] It should be noted that the first cooling temperature T1 can be lower than room temperature, and does not need to be lower, and can be set between 1-10°C, such as 5°C, and the second cooling temperature T2 is to make the second type of plastic more brittle to facilitate crushing, so the second cooling temperature T2 is lower than 0°C, and can be set between -20-0°C, such as -5°C. In this embodiment, for the purpose of saving energy, the first cooling temperature T1 can be set to 10°C, and the second cooling temperature T2 can be set to -3°C.

[0025] In one embodiment, in step S100, the plastic is washed, dehydrated, and then cooled. After washing the plastic, the plastic contains more water, which will affect the crushing efficiency. Dehydration can reduce the water content of the plastic, thereby making crushing more convenient.

[0026] In one embodiment, in step S400, the mass M1 of the first type of plastic and the mass M2 of the second type of plastic that have been sorted are measured, and the cooling temperature and the speed of conveying the second type of plastic are adjusted according to the ratio K between the mass M1 of the first type of plastic and the total mass M1+M2 of the plastic. In order to save energy and reduce crushing costs, in step S400, the mass M1 of the first type of plastic and the mass M2 of the second type of plastic are first measured, and then the cooling temperature and the speed of conveying the second type of plastic are adjusted according to the ratio K between the mass M1 of the first type of plastic and the total mass M1+M2 of the plastic, wherein the cooling temperature can be adjusted by adjusting only the first cooling temperature T1 or the second cooling temperature T2, or by adjusting the first cooling temperature T1 and the second cooling temperature T2 at the same time, and adjusting the speed of conveying the second type of plastic means increasing or decreasing the speed of conveying the second type of plastic.

[0027] In one embodiment, preset values ​​C1, C2 and C3 are set, and C1<C2<C3. By comparing the ratio K with the preset values ​​C1, C2 and C3, it is determined how to adjust the cooling temperature and the speed of conveying the second type of plastic, so as to achieve the purpose of saving energy consumption and reducing crushing costs while ensuring the crushing effect. Among them, C1 is closer to 0, C2 is closer to 0.5, and C3 is closer to 1. In this embodiment, C1 can be set to 0.1, C2 to 0.5, and C3 to 0.9. In other embodiments, C1 can be 0.05, C2 can be 0.6, and C3 can be 0.95.

[0028] In one embodiment, when the ratio K is less than or equal to the first setting parameter C1, the first cooling temperature T1 and the second cooling temperature T2 are reduced, and the speed of conveying the second type of plastic in step S400 is increased. This situation indicates that the mass M1 of the first type of plastic accounts for a very small proportion of the total mass of the plastic, that is, there are very few granular plastics and a lot of film or sheet plastics, which further indicates that the crushing effect of the plastic is poor during the initial crushing. At this time, the effect of the initial crushing is improved by reducing the first cooling temperature T1. At the same time, since the specific gravity of the second type of plastic is relatively large, by reducing the second cooling temperature T2 and increasing the speed of conveying the second type of plastic, a large amount of the second type of plastic can be quickly cooled and conveyed, and while improving the crushing effect of the second type of plastic, the accumulation of the second type of plastic can be avoided.

[0029] In one embodiment, when the ratio K is greater than the first setting parameter C1 and less than the second setting parameter C2, the second cooling temperature T2 is reduced, and the speed of conveying the second type of plastic in step S400 is increased. This situation indicates that the second type of plastic is relatively more, and the difference between the two is not very large, that is, the film or sheet plastic is relatively more, and the plastic particles are relatively less, indicating that the effect of the initial crushing basically meets the requirements. At this time, by reducing the second cooling temperature T2 and increasing the speed of conveying the second type of plastic, a large amount of the second type of plastic can be quickly cooled and conveyed, while improving the crushing effect of the second type of plastic and avoiding the accumulation of the second type of plastic.

[0030] In one embodiment, when the ratio K is greater than or equal to the second setting parameter C2 and less than or equal to the third setting parameter C3, the second cooling temperature T2 is increased, and the speed of conveying the second type of plastic in step S400 is reduced. This situation indicates that there are more first type of plastics, and the difference between the two is not very large, that is, there are more granular plastics and less film or sheet plastics, indicating that the effect of the initial crushing basically meets the requirements. At this time, in order to reduce energy consumption, the second cooling temperature T2 is increased, and the speed of conveying the second type of plastic in step S400 is reduced. In this way, the cooling time of the second type of plastic is extended, so that the second type of plastic can be fully cooled without the need for a lower cooling temperature, thereby saving refrigeration energy consumption.

[0031] In one embodiment, when the ratio K is greater than the third setting parameter C3, the cooling of the second type of plastic is stopped. This situation indicates that there are a lot of first type plastics and almost no second type plastics, indicating that the effect of the initial crushing is very good. At this time, in order to reduce energy consumption, the cooling of the second type of plastic can be stopped, and a very small amount of the second type of plastic can be directly crushed for the second time.

[0032] Refer to the following Figure 2 , describing a pretreatment device for recycling waste plastics provided in an embodiment of the second aspect of the present invention.

[0033] The pretreatment device for recycling waste plastics in this embodiment is used to implement the pretreatment process for recycling waste plastics in the embodiment of the first aspect.

[0034] The pretreatment device for recycling waste plastics in this embodiment includes a first cooling module, a first crushing module, a sorting module, a second cooling module, a second crushing module and a control module; the first cooling module is used to cool the cleaned plastic; the first crushing module is used to crush the plastic discharged from the first cooling module; the sorting module is used to sort the plastic after the initial crushing into a first type of plastic and a second type of plastic, the second cooling module is used to cool the second type of plastic, the second crushing module is used to crush the first type of plastic and the cooled second type of plastic, and the control module is used to adjust the cooling temperature of the first cooling module and the second cooling module and the speed of conveying the second type of plastic according to the ratio between the mass of the first type of plastic and the total mass of the plastic.

[0035] Specifically, Figure 2 As shown, the pretreatment device for recycling waste plastics in this embodiment includes a frame 100, on which a first conveyor belt 210 and a first cooling chamber 220 are arranged, the first cooling temperature in the first cooling chamber 220 is T1, the first cooling chamber 220 constitutes a first cooling module, a first crushing chamber 230 is arranged at the end of the first conveyor belt 210, a first crushing assembly is arranged in the first crushing chamber 230, and the first crushing assembly and the first crushing chamber 230 constitute a first crushing module.

[0036] A sorting fan 240 is also provided on the frame 100 , and the air outlet of the sorting fan 240 faces the first crushing chamber 230 , so that the plastic after the primary crushing can be sorted. The sorting fan 240 constitutes a sorting module.

[0037] The first crushing chamber 230 has a first discharge port and a second discharge port, a second conveyor belt 310 is arranged below the first discharge port, the first type of plastic falls on the second conveyor belt 310 after coming out of the first discharge port of the first crushing chamber 230, a third conveyor belt 330 is arranged on one side of the second discharge port, and a second cooling chamber 320 is also arranged on the frame 100, the first cooling temperature in the second cooling chamber 320 is T2, and the second type of plastic falls on the third conveyor belt 330 after coming out of the second discharge port of the first crushing chamber 230.

[0038] A second crushing chamber 350 is also provided on the frame 100, and a second crushing assembly is provided in the second crushing chamber 350. The second crushing chamber 350 and the second crushing assembly constitute a second crushing module. The second conveyor belt 310 and the third conveyor belt 330 can respectively convey the first type of plastic and the second type of plastic into the second crushing chamber 350, so that the second crushing assembly can perform secondary crushing on the two types of plastic.

[0039] The control module is arranged on the frame 100, and the second conveyor belt 310 is provided with a first weighing sensor, which is used to measure the mass of the first type of plastic coming out of the first discharge port, and the third conveyor belt 330 is provided with a second weighing sensor, which is used to measure the mass of the second type of plastic coming out of the second discharge port. The control module can control the conveying speed of the first conveyor belt 210, the second conveyor belt 310 and the third conveyor belt 330 according to the ratio K between the mass of the first type of plastic and the total mass of the plastic, and can also control the cooling temperature in the first cooling cavity 220 and the second cooling cavity 320. The control program of the control module is provided with preset values ​​C1, C2 and C3, and C1<C2<C3. By comparing the ratio K with the preset values ​​C1, C2 and C3, it is determined how to adjust the cooling temperature and the speed of conveying the second type of plastic, so as to achieve the purpose of saving energy consumption and reducing crushing costs. Among them, C1 is closer to 0, C2 is closer to 0.5, and C3 is closer to 1. In this embodiment, C1 can be set to 0.1, C2 to 0.5, and C3 to 0.9. In other embodiments, C1 can be set to 0.05, C2 to 0.6, and C3 to 0.95.

[0040] Since the plastic is easy to adhere to the third conveyor belt 330 after being cooled, in order to fully crush the second type of plastic, the frame 100 is also provided with a scraper 340 tangent to the end of the third conveyor belt 330. The scraper 340 can scrape off the second type of plastic adhering to the third conveyor belt 330, so that the second type of plastic falls smoothly into the second cooling chamber 320.

[0041] The working process of the pretreatment device for recycling waste plastics in this embodiment is as follows: When in use, the washed and dehydrated plastic is placed on the first conveyor belt 210, wherein the first cooling temperature in the first cooling chamber 220 is T1, and the second cooling temperature in the second cooling chamber 320 is T2. After being cooled by the first cooling temperature T1, the plastic enters the first crushing chamber 230. After being crushed by the first crushing assembly, the first type of plastic enters the second conveyor belt 310, and the first weighing sensor measures the mass of the first type of plastic as M1. The second type of plastic enters the third conveyor belt 330, and the second weighing sensor measures the mass of the second type of plastic as M2. The first type of plastic is directly conveyed into the second crushing chamber 350 by the second conveyor belt 310, and the second type of plastic is conveyed into the second crushing chamber 350 by the third conveyor belt 330 after being cooled by the second cooling chamber 320.

[0042] During use, when the ratio K is less than or equal to the first setting parameter C1, the control module reduces the first cooling temperature T1 in the first cooling chamber 220 and the second cooling temperature T2 in the second cooling chamber 320, and increases the speed of the third conveyor belt 330 conveying the second type of plastic. This situation indicates that the mass M1 of the first type of plastic accounts for a very small proportion of the total mass of the plastic, that is, there are fewer granular plastics and more film-like or sheet-like plastics, which further indicates that the crushing effect of the plastic is poor during the initial crushing. At this time, the effect of the initial crushing is improved by reducing the first cooling temperature T1. At the same time, since the mass of the second type of plastic is large, by reducing the second cooling temperature T2 and increasing the speed of conveying the second type of plastic, a large amount of the second type of plastic can be quickly cooled and conveyed, and the second type of plastic can be prevented from accumulating while improving the crushing effect of the second type of plastic.

[0043] When the ratio K is greater than the first setting parameter C1 and less than the second setting parameter C2, the control module reduces the second cooling temperature T2 in the second cooling chamber 320 and increases the speed of the third conveyor belt 330 conveying the second type of plastic. This situation indicates that there are more second type of plastics and the difference between the two is not very large, that is, there are more film-like or sheet-like plastics and fewer plastic-like particles, indicating that the effect of the initial crushing basically meets the requirements. At this time, by reducing the second cooling temperature T2 and increasing the speed of conveying the second type of plastics, a large amount of second type of plastics can be quickly cooled and conveyed, and the second type of plastics can be prevented from accumulating while improving the crushing effect of the second type of plastics.

[0044] When the ratio K is greater than or equal to the second setting parameter C2 and less than or equal to the third setting parameter C3, the control module increases the second cooling temperature T2 in the second cooling chamber 320 and reduces the speed of the third conveyor belt 330 conveying the second type of plastic. This situation indicates that there are more first type plastics and the difference between the two is not very large, that is, there are more granular plastics and less film or sheet plastics, indicating that the effect of the initial crushing basically meets the requirements. At this time, in order to reduce energy consumption, the second cooling temperature T2 is increased and the speed of the third conveyor belt 330 conveying the second type of plastic is reduced. In this way, the cooling time of the second type of plastic is extended, so that the second type of plastic can be fully cooled without the need for a lower cooling temperature, thereby saving refrigeration energy consumption.

[0045] When the ratio K is greater than the third setting parameter C3, the control module controls the refrigeration process of the second cooling chamber 320, and then stops cooling the second type of plastic. This situation indicates that there are a lot of first type plastics and almost no second type plastics, indicating that the effect of the initial crushing is very good. At this time, in order to reduce energy consumption, the cooling of the second type of plastic can be stopped, and a very small amount of the second type of plastic can be directly crushed for the second time.

[0046] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, 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.

[0047] The above-mentioned embodiments only express several implementation methods of the present invention, and the description thereof is relatively specific and detailed, but it cannot be understood as limiting the scope of the patent of the present invention. It should be pointed out that, for ordinary technicians in this field, several variations and improvements can be made without departing from the concept of the present invention, which all belong to the protection scope of the present invention. Therefore, the protection scope of the patent of the present invention shall be subject to the attached claims.

Claims

1. A pretreatment process for recycling waste plastics, It is characterized in that The following steps are involved: S100: Cooling the cleaned plastic at a first cooling temperature T1; S200: Initially crush the cooled plastic; S300: sorting the plastics after primary crushing into first-class plastics and second-class plastics; S400: performing secondary crushing on the first type of plastic, cooling the second type of plastic at a second cooling temperature T2, and performing secondary crushing on the cooled second type of plastic, wherein the second cooling temperature T2 is lower than the first cooling temperature T1.

2. The pretreatment process for recycling waste plastics according to claim 1, It is characterized in that In step S100, the plastic is washed, dehydrated, and then cooled.

3. The pretreatment process for recycling waste plastics according to claim 1, It is characterized in that In step S400, the mass M1 of the sorted first type of plastic and the mass M2 of the sorted second type of plastic are measured, and the cooling temperature and the speed of conveying the second type of plastic are adjusted according to the ratio K between the mass M1 of the first type of plastic and the total mass M1+M2 of the plastic.

4. The pretreatment process for recycling waste plastics according to claim 3, It is characterized in that When the ratio K is less than or equal to the first setting parameter C1, the first cooling temperature T1 and the second cooling temperature T2 are lowered, and the speed of conveying the second type of plastic in step S400 is increased.

5. The pretreatment process for recycling waste plastics according to claim 3, It is characterized in that When the ratio K is greater than the first setting parameter C1 and less than the second setting parameter C2, the second cooling temperature T2 is lowered, and the speed of conveying the second type of plastic in step S400 is increased.

6. The pretreatment process for recycling waste plastics according to claim 3, It is characterized in that When the ratio K is greater than or equal to the second setting parameter C2 and less than or equal to the third setting parameter C3, the second cooling temperature T2 is increased, and the speed of conveying the second type of plastic in step S400 is reduced.

7. The pretreatment process for recycling waste plastics according to claim 3, It is characterized in that When the ratio K is greater than the third setting parameter C3, cooling of the second type of plastic is stopped.

8. The pretreatment process for recycling waste plastics according to claim 1, It is characterized in that In step S300, the plastic after primary crushing is sorted into the first type of plastic and the second type of plastic by blowing.

9. A pretreatment device for recycling waste plastics, It is characterized in that A pretreatment process for recycling waste plastics used to implement any one of claims 1 to 8, the pretreatment device for recycling waste plastics comprises a first cooling module, a first crushing module, a sorting module, a second cooling module, a second crushing module and a control module; the first cooling module is used to cool the cleaned plastic; the first crushing module is used to crush the plastic discharged from the first cooling module; the sorting module is used to sort the plastic after the initial crushing into a first type of plastic and a second type of plastic, the second cooling module is used to cool the second type of plastic, the second crushing module is used to crush the first type of plastic and the cooled second type of plastic, and the control module is used to adjust the cooling temperature of the first cooling module and the second cooling module and the speed of conveying the second type of plastic according to the ratio between the mass of the first type of plastic and the total mass of the plastic.

10. The pretreatment device for recycling waste plastics according to claim 9, It is characterized in that The sorting module is a sorting fan.

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