Waste plastic recycling system and method by composite sorting

Abstract

The recycling system for waste plastic according to the present invention comprises: a raw material supply unit that collects and supplies various types of waste wires; a crushing unit that crushes the supplied raw material to process it into a mixture of non-ferrous metal and mixed plastic sludge; a wet specific gravity separation unit that separates non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge; a drying unit that dries the residue remaining after separating non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge to process it into mixed plastic sludge; a particle size separation unit that separates fine metal particles from the dried mixed plastic sludge; an eddy current separation unit that further separates minute amounts of metals from the particle size-separated mixed plastic sludge to separate metals that are foreign substances in the final plastic product using eddy currents; a melting unit that melts the final mixed plastic sludge provided through the eddy current separation unit; and a molding unit that molds a product using injection molding or a mold with the molten material provided through the melting unit.

Description

Technology Field

[0001] The present invention relates to a recycling system and method for waste plastics discharged from collected waste wires, and more specifically, to a recycling system and method for collected waste wires that crushes collected waste wires and separates them into non-ferrous metals and mixed plastic sludge, and enables the production of various injection molded products after the collection of mixed plastic sludge is sorted twice and additional fine metal particles are recovered. Background Technology

[0002] In general, while the living standards of the people in Korea have improved due to rapid economic growth and industrial development, household and industrial waste is increasing rapidly as a result.

[0003] Plastic is an indispensable material in modern times with a very wide range of applications. It consists of a wide variety of types, such as PP, PE, PS, PET, PVC, as well as HDPE and LDPE. Among household and industrial waste, vinyl is a type of synthetic plastic and is widely used as the most commonly used household item.

[0004] This is because it is not only convenient to use and affordable, but can also be processed into various shapes and functions.

[0005] Among plastics, waste wires collected from various industrial wastes are crushed and separated into mixed plastic sludge and non-ferrous metals for the recycling of conductive metals such as non-ferrous metals, and the mixed plastic sludge is recycled into various recycled plastic products.

[0006] Public Patent No. 2025-0004424 describes a recycling system and method for separated waste plastics that improves the purity of waste plastics and enhances the performance of injection molded products by utilizing two-stage screen filters of different sizes to separate foreign substances.

[0007] However, there is a problem in that the mixed plastic sludge remaining after grinding waste wires and separating non-ferrous metals by specific gravity contains metals that are not recovered, making it difficult to filter them out by particle separation alone.

[0008] Therefore, a system for screening and removing micro-metal particles contained in mixed plastic sludge is required. The problem to be solved

[0009] Accordingly, the present invention aims to solve the above problems and provides a recycling system and method for waste wires that can increase the recycling rate by crushing various types of collected waste wires, separating them into non-ferrous metals and mixed plastic sludge by gravity separation, and then separating and recovering fine metal particles contained in the mixed plastic sludge. means of solving the problem

[0010] A recycling system for waste plastic according to the present invention for achieving the above-mentioned purpose comprises: a raw material supply unit that collects and supplies various types of waste wires; a crushing unit that crushes the supplied raw material to process it into a mixture of non-ferrous metal and mixed plastic sludge; a wet specific gravity separation unit that separates non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge; a drying unit that dries the residue remaining after separating non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge to process it into mixed plastic sludge; a particle size separation unit that separates fine metal particles from the dried mixed plastic sludge; an eddy current separation unit that further separates minute amounts of metals from the particle size-separated mixed plastic sludge to separate metals that are foreign substances in the final plastic product using eddy currents; a melting unit that melts the final mixed plastic sludge provided through the eddy current separation unit; and a molding unit that molds a product using injection molding or a mold with the molten material provided through the melting unit.

[0011] The above-described eddy current sorting unit comprises: a base frame; an input unit disposed on one side of the base frame and into which a sorting target (M), formed by crushing waste resources, is supplied; an output unit disposed on the other side of the base frame; a conveyor belt disposed on the base frame to transport the sorting target (M) from the input unit to the output unit; first and second belt rollers disposed at both inner ends of the conveyor belt and connected to a first drive motor to drive the conveyor belt; and a magnetic rotor disposed eccentrically inside the second belt roller disposed on the output unit side among the first and second belt rollers, and formed an eddy current through rotation by the second drive motor to sort non-ferrous metals from the sorting target (M).

[0012] The inner surface of the second belt roller and the outer surface of the magnetic rotor are spaced apart at a predetermined interval, and are configured so that the interval can be adjusted within a predetermined range.

[0013] The invention is further characterized by having a splitter positioned at the lower part of the discharge section and spaced apart from the other end of the conveyor belt to guide the non-ferrous metal classified and falling from the sorting target (M) downward.

[0014] The upper portion of the splitter is characterized by being formed as a curved section bent toward the conveyor belt to reduce the distance between the center of the magnetic rotor and the splitter.

[0015] The curved portion of the splitter is characterized by being configured to have the same curvature as the second belt roller.

[0016] The above waste plastic recycling step comprises: a step of collecting various types of waste wires and supplying them as raw materials; a step of crushing the supplied raw materials to process them into a mixture of non-ferrous metals and mixed plastic sludge; a step of wet specific gravity separation to separate non-ferrous metals from the mixture of non-ferrous metals and mixed plastic sludge; a drying step to dry the residue remaining after separating non-ferrous metals from the mixture of non-ferrous metals and mixed plastic sludge to process it into mixed plastic sludge; a particle size separation step to separate fine metal particles from the dried mixed plastic sludge; a step of eddy current separation to further separate minute amounts of metals from the particle size-separated mixed plastic sludge to separate the metals that are foreign substances in the final plastic product; a step of melting the final mixed plastic sludge separated by eddy current; and a step of molding a product using injection molding or a mold with the molten material provided through the melting section. Effects of the invention

[0017] By the recycling system and method for waste plastic discharged from separated waste wires according to the above configuration, the metal recovery rate is increased by recovering fine metal particles through additional eddy current separation after separating the mixed plastic sludge twice, and the metal particles corresponding to foreign substances in the plastic sludge used for molding plastic products are reduced, thereby improving the quality of plastic products. Brief explanation of the drawing

[0018] FIG. 1 is a block diagram of a waste plastic recycling system according to the present invention. FIG. 2 is a cross-sectional view showing an eddy current sorting unit according to the present invention. FIG. 3 is a cross-sectional view showing an embodiment of a splitter according to the present invention. Specific details for implementing the invention

[0019] Below, embodiments of the present invention are described in detail with reference to the attached drawings so that those skilled in the art can easily implement the invention.

[0020] The scope of the present invention shall not be interpreted as being limited by the embodiments described in the text.

[0021] Hereinafter, embodiments of the present invention will be described in detail with reference to the drawings. In the description of the embodiments, the same reference numerals are assigned to identical components, and in some cases, the description of the same reference numerals is omitted.

[0022] FIG. 1 is a block diagram of a recycling system for waste plastic separated from waste wires according to the present invention. As illustrated, the present invention is composed of a raw material supply unit (1), a crushing unit (2), a wet specific gravity sorting unit (3), a drying unit (4), a particle size sorting unit (5), an eddy current sorting unit (6), a sludge supply unit (7), a melting unit (8), and a molding unit (9).

[0023] The raw material supply unit (1) according to the present invention collects various types of waste wires, and the collected waste wires are transported to a location to be processed using a conveyor and supplied to the location to be processed.

[0024] The supplied waste wire is crushed in the crushing unit (2) and mixed with non-ferrous metal and plastic sludge.

[0025] The non-ferrous metal and mixed plastic sludge supplied from the crushing unit (2) is passed through the wet specific gravity sorting unit (3), and the non-ferrous metal and mixed plastic sludge are separated according to the difference in specific gravity in the wet specific gravity sorting unit (3), and the non-ferrous metal with a higher specific gravity is discharged.

[0026] The mixed plastic sludge that has passed through the wet specific gravity sorting section (3) is supplied to the drying section (4) to be dried into particle form.

[0027] The dried mixed plastic sludge passes through the particle size sorting section (5) and additionally discharges non-ferrous metal particles in the form of fine particles.

[0028] The eddy current sorting unit (6) utilizes eddy currents to filter out smaller non-ferrous metal particles by removing fine non-ferrous metal particles that are difficult to separate with the remaining permanent magnets in order to improve the purity of the mixed sludge.

[0029] The mixed plastic sludge, from which even relatively small particles of non-blue metal are removed through the eddy current sorting section (6), is supplied to the melting section (8) through the sludge supply section (7) and heated.

[0030] The molten mixed plastic sludge allows the molten material to be injected through the molding section (9) or molded into a product using a mold.

[0031] As shown in FIG. 2, the discharge unit (30) according to the present invention is positioned on the other side of the base frame (10) and configured to discharge mixed plastic sludge and non-ferrous metal contained in the sorting target (M).

[0032] In this case, the mixed plastic sludge is transported along the direction of movement of the conveyor belt (40) and discharged by falling vertically to the discharge section (30), and the non-ferrous metal is thrown or bounced a certain distance from the other side of the conveyor belt (40) by the repulsive force of the eddy current by the magnetic rotor (60) and discharged by falling through the discharge section (30).

[0033] In addition, at the lower part of the discharge section (30), that is, at the lower part of the other end of the conveyor belt (40), first and second sorting boxes (33) are provided for loading classified mixed plastic sludge and non-ferrous metal, and mixed plastic sludge is loaded in the first sorting box (31), and non-ferrous metal is loaded in the second sorting box (33).

[0034] The conveyor belt (40) is positioned on the base frame (10) and configured to transport the sorting target (M) supplied through the input section (20) to the discharge section (30).

[0035] A first belt roller (50A) and a second belt roller (50B) are arranged at both inner ends of the conveyor belt (40), and a first drive motor (41) is connected to the first belt roller (50A) to drive it. The first belt roller (50A) and the second belt roller (50B) are configured to be linked by means of a pulley and a drive belt, etc. In this case, it is preferable that the first belt roller (50A) and the second belt roller (50B) be composed of hollow cylindrical rollers.

[0036] Additionally, a plurality of guide rollers (43) may be arranged between the first and second belt rollers (50A) (50B) on the upper inner side of the conveyor belt (40) to prevent sagging of the conveyor belt (40) or to enable smooth circulation. Such guide rollers (43) may also be arranged below the second belt roller (50B) to form a circulation path of the conveyor belt (40) or to maintain constant tension of the conveyor belt (40).

[0037] The magnetic rotor (60) is eccentrically positioned inside the second belt roller (50B) located on the discharge side (30) and is configured to form eddy currents through rotation by the second drive motor (61).

[0038] The magnetic rotor (60) is eccentrically positioned inside the second belt roller (50B), whereas in the case of a conventional magnetic rotor (60), it is positioned inside the belt roller and configured to have the same center of rotation as the belt roller. In this case, if the distance between the magnetic rotor and the object to be sorted (M) is long, the strength of the eddy current decreases, making sorting difficult; therefore, the diameter of the magnetic rotor (60) is made as large as possible, but it is manufactured so as not to come into contact with the inner surface of the belt roller.

[0039] Therefore, there is a problem that the size of the magnetic rotor (60) is increased, and as a result, the weight of the magnetic rotor (60) is also increased, so the power consumption is also increased.

[0040] The magnetic rotor (60) is positioned eccentrically inside the second belt roller (50B) to reduce the size and weight of the magnetic rotor (60). Reducing the size and weight of the magnetic rotor (60) in this way is advantageous in that it not only reduces power consumption but also reduces manufacturing costs.

[0041] The magnetic rotor (60) configured in this manner is connected to the second drive motor (61) and rotated to drive it. Through the rotational drive of the magnetic rotor (60), non-ferrous metals such as copper or aluminum are ejected in the direction of transport of the sorting target (M) by the repulsive force generated by the eddy current and the transport speed of the conveyor belt (40), and fall into the second sorting box (33) to be loaded.

[0042] In this case, it is preferable to limit the number of magnetic stimuli in the magnetic rotor (60) to 10 to 15. If the number of stimuli is 15 or more, it is advantageous for forming a magnetic field, but the stimuli inserted into the magnetic rotor (60) itself have a relatively small volume, which may cause problems with durability performance.

[0043] In addition, the magnetic field strength of the magnetic rotor (60) is formed to be 5,000 to 10,000 gauss. Although the magnetic field strength can be lowered as the number of magnetic poles increases, it is preferable to limit the number to 15 or fewer and set the magnetic field strength to at least 5,000 gauss. In addition, if the number of magnetic poles is to be 10 or fewer, the magnetic field strength must be at least 10,000 gauss. However, it is preferable to use a neodymium magnet, which is a permanent magnet with added neodymium (Nd), with an optimal number of magnetic poles of 10 or more and a magnetic field strength of 10,000 gauss or less.

[0044] The eddy current intensity generated by the magnetic rotor (60) as described above can be determined by the number of magnetic poles, rotational speed, rotational direction of the magnetic rotor (60), and the conveying speed of the conveyor belt (40), and can also be determined by the type of non-ferrous metal contained in the crushed sorting object (M), or the scrap size or particle size.

[0045] However, the principle of eddy current generation by the magnetic rotor (60) in this specification is disclosed in many literatures, so a detailed explanation thereof will be omitted.

[0046] Meanwhile, the magnetic rotor (60) and the second belt roller (50B) are arranged to be spaced apart from each other. Since the separation power by the generated eddy current can be increased only when the distance between the magnetic rotor (60) and the object to be sorted (M) (non-ferrous metal) is close, it is desirable to maintain a minimum distance between the outer surface of the magnetic rotor (60) and the inner surface of the second belt roller.

[0047] In this case, since the eddy current intensity may vary depending on the type of non-ferrous metal, such as the current conduction rate or specific gravity, it is also desirable to install the magnetic rotor (60) and the second belt roller (50B) so that the separation distance between them can be adjusted to control the separation power of the non-ferrous metal.

[0048] The mixed plastic sludge and non-ferrous metal classified by eddy currents fall into the first classification box (31) and the second classification box (33), respectively, as described above, and are loaded.

[0049] In this case, since the mixed plastic sludge is not subject to the eddy current, it falls vertically from the other end of the conveyor belt (40) and is loaded into the first sorting bin (31), and the non-ferrous metal is bounced in the conveying direction of the conveyor belt (40) by the eddy current and falls into the second sorting bin (33), which is positioned slightly away from the first sorting bin (31), and is loaded.

[0050] In this way, the mixed plastic sludge and non-ferrous metal are loaded into each sorting container. In particular, since the non-ferrous metal is ejected from the conveyor belt (40) and falls after flying a certain distance, it is desirable to provide a splitter (70) to guide it so that the non-ferrous metal is guided into the second sorting container (33).

[0051] That is, it is preferable that the splitter (70) be positioned between the first sorting box (31) and the second sorting box (33), or on the side of the second sorting box (33) that is close to the first sorting box (31). In addition, the splitter (70) is formed to be inclined downward while positioned so that its upper end is close to the conveyor belt (40), so that non-ferrous metals that are flung off from the conveyor belt (40) can fall onto the inclined surface of the splitter (70) and be loaded into the second sorting box (33).

[0052] Meanwhile, the gap between the splitter (70) and the magnetic rotor (60) needs to be minimized, because the repulsive force caused by eddy currents varies depending on the type of non-ferrous metal, the difference in specific gravity, scrap or particle size, etc., and thus the distance it flies away from the conveyor belt (40) also varies.

[0053] Therefore, the gap between the splitter (70), more specifically between the top of the splitter (70) and the magnetic rotor (60) must be minimized so that non-ferrous metal can fall into the splitter (70) and be loaded into the second sorting container (33). However, even if the gap between the splitter (70) and the magnetic rotor (60) is minimized, the downward path of the mixed plastic sludge falling vertically from the conveyor belt (40) must be maintained so that a complete sorting operation is possible.

[0054] Accordingly, in the present invention, the upper part of the splitter (70) may be formed with a curved section (71) that is bent toward the conveyor belt (40) to reduce the distance between the center of the magnetic rotor (60) and the splitter (70).

[0055] That is, as illustrated in FIG. 3, when the splitter (70) is in a straight line shape, the distance between the center of the magnetic rotor (60) and the top of the splitter (70) is 'a', whereas when the top of the splitter (70) is formed as a curved section (71), the distance between the center of the magnetic rotor (60) and the top of the splitter (70) becomes 'b', which is narrower than 'a'.

[0057] In addition, to prevent the curved section (71) from encroaching upon the downward path of the mixed plastic sludge, it is preferable that the curved section (71) of the splitter (70) be configured to have the same curvature as the second belt roller (50B). As shown in FIG. 3, the curved section (71) is positioned to cover the upper part of the second belt roller (50B), thereby forming a certain gap between the conveyor belt (40) and the curved section (71). This gap not only forms a flow path or downward path for the mixed plastic sludge but also serves to guide the vertical falling motion.

[0058] This is because when the top of the splitter (70) is provided in a straight shape, fine powder or low-density components in the mixed plastic sludge may fly up when falling, and the same phenomenon may occur due to external factors, causing them to go over the top of the splitter (70) and mix with non-ferrous metals.

[0059] In this way, the present invention forms a curved portion (71) at the top of the splitter (70) to minimize the gap between the center of the magnetic rotor (60) and the splitter (70), thereby improving the classification performance of non-ferrous metals and preventing mixing between non-ferrous metals and mixed plastic sludge, thereby ensuring the reliability of the device. Explanation of the symbols

[0060] 1 : Raw Material Supply Unit 2 : Grinding section 3 : Wet Specific Gravity Separator 4 : Drying section 5 : Particle Size Sorting Unit 6 : Eddy current sorting unit 7 : Sludge supply unit 8 : Molten zone 9 : Molding part M : Selection target 10 : Base frame 11 : Cover 13 : Inspection window 15 : Support Frame 20 : Input section 30 : Discharge part 31 : Classification 1 33 : Classification 2 40 : Conveyor belt 41: 1st drive motor 43: Guide roller 50A: 1st belt roller 50B: 2nd belt roller 60: Magnetic rotor 61 : Second drive motor 70 : Splitter 71 : Curved section

Claims

Claim 1 A recycling system for waste plastic comprising: a raw material supply unit (1) that collects and supplies various types of waste wires; a crushing unit (2) that crushes the supplied raw material to process it into a mixture of non-ferrous metal and mixed plastic sludge; a wet specific gravity sorting unit (3) that separates non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge; a drying unit (4) that dries the residue remaining after separating non-ferrous metal from the mixture of non-ferrous metal and mixed plastic sludge to process it into mixed plastic sludge; a particle size sorting unit (5) that separates fine metal particles from the dried mixed plastic sludge; an eddy current sorting unit (6) that further separates minute amounts of metals from the particle size sorted mixed plastic sludge to separate metals that are foreign substances in the final plastic product using eddy currents; a melting unit (8) that melts the final mixed plastic sludge provided through the eddy current sorting unit; and a molding unit (9) that molds a product using injection molding or a mold with the molten material provided through the melting unit. Claim 2 In claim 1, the eddy current sorting unit (6) comprises: a base frame (10); an input unit (20) disposed on one side of the base frame (10) and into which a sorting target body (M) formed by crushing waste resources is supplied; an output unit (30) disposed on the other side of the base frame (10); a conveyor belt (40) disposed on the base frame (10) to transport the sorting target body (M) from the input unit (20) to the output unit (30); and first and second belt rollers (50A) (50B) disposed at both inner ends of the conveyor belt (40) and connected to a first drive motor (41) to drive the conveyor belt (40). A recycling system for waste plastic comprising: a magnetic rotor (60) eccentrically disposed inside the second belt roller (50B) positioned on the discharge side (30) among the first and second belt rollers (50A) (50B), and forming an eddy current through rotation by a second drive motor (61) to classify non-ferrous metals from a sorting target (M). Claim 3 A recycling system for waste plastic according to claim 2, characterized in that the inner surface of the second belt roller (50B) and the outer surface of the magnetic rotor (60) are spaced apart at a predetermined interval, and the interval can be adjusted within a predetermined range. Claim 4 A recycling system for waste plastic according to claim 2, further comprising a splitter (70) positioned at the lower side of the discharge section (30) and spaced apart from the other end of the conveyor belt (40) to guide downward non-ferrous metals classified and falling from the sorting target (M). Claim 5 A recycling system for waste plastic according to claim 4, characterized in that the upper end of the splitter (70) is formed with a curved section (71) bent toward the conveyor belt (40) to reduce the distance between the center of the magnetic rotor (60) and the splitter (70). Claim 6 A recycling system for waste plastic according to claim 5, characterized in that the curved portion (71) of the splitter (70) is configured to have the same curvature as the curvature of the second belt roller (50B). Claim 7 A method for recycling waste plastic comprising: a step of collecting various types of waste wires and supplying them as raw materials; a step of crushing the supplied raw materials to process them into a mixture of non-ferrous metals and mixed plastic sludge; a step of wet specific gravity separation to separate non-ferrous metals from the mixture of non-ferrous metals and mixed plastic sludge; a drying step to dry the residue remaining after separating non-ferrous metals from the mixture of non-ferrous metals and mixed plastic sludge to process it into mixed plastic sludge; a particle size separation step to separate fine metal particles from the dried mixed plastic sludge; a step of eddy current separation to further separate minute amounts of metals from the particle size-separated mixed plastic sludge to separate metals that are foreign substances in the final plastic product; a step of melting the final mixed plastic sludge separated by eddy current; and a step of molding a product using injection molding or a mold with the molten material provided through the melting section.

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