JP2010167727A - Pretreatment method in classifying material quality of waste plastic crushed piece - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a pretreatment method for classifying material quality with sufficient purity in classifying the material quality of a crushed piece raw material of crushed waste plastic. <P>SOLUTION: A method for classifying the quality of the waste plastic crushed piece raw material obtained when disassembling and crushing waste plastic products or the like and classifying them every valuable to recycle them comprises a heat pretreatment process (a heating process) for heating the waste plastic crushed pieces at a predetermined temperature at which the waste plastic crushed pieces are thermally deformed in a pre-process of material quality classification (a plastic sorting process) at least. The waste plastic crushed pieces supplied for the material quality classification (the plastic sorting process) are respectively separated without being in the mutually connected state under drawing action (restoring action) due to thermal deformation by heating, and furthermore, shape is made simple. The waste plastic crushed pieces can thereby be classified one by one in material quality classification, and in consequence, the raw material waste plastic crushed pieces can be classified with sufficient purity. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  The present invention relates to a technology for recycling valuable materials by decomposing and crushing used home electric appliances and the like that are discarded from homes, and more particularly, to a pretreatment method when separating waste plastic fragments (materials). Is.

  Conventionally, disposal methods for waste home appliances such as washing machines, refrigerators, televisions and air conditioners have been taken up as they are, or crushed or incinerated. However, these disposal methods have problems such as shortage of landfills and global warming due to the generation of harmful gases during incineration. They are separated and reused (recycled) as raw materials.

  As a method for individually separating valuable materials such as metals and plastics from waste home appliances, for example, there is a technique disclosed in Patent Document 1. This product first separates and collects specific parts such as refrigerant freon and cathode ray tubes from waste home appliances in consideration of the environmental impact, and crushes the remaining waste home appliances collectively. Then, the crushed pieces (mixture) are crushed into a magnetic separator and eddy current separator to separate and remove iron and non-ferrous metals (copper, aluminum, etc.), and the remaining crushed pieces are finely crushed again and passed through a specific gravity sorter. Separating into metal-based heavy weight crushing pieces and waste plastic (waste plastic crushing pieces) that have not been sorted in the previous process, the separated waste plastic crushing pieces are subjected to a specific gravity sorter and are divided into two kinds of different materials. Sort. The waste plastic crushed pieces thus separated are kneaded and granulated by a screw-type extruder and recycled to a recycled resin.

  In addition to the specific gravity sorting method, an optical sorting method and a wind force sorting method are known as methods for separating the waste plastic crushed material. The optical sorting method (e.g., Patent Document 2) transfers the raw material waste plastic crushed pieces by a belt conveyor and discharges them from the terminal end, and optically discriminates the waste plastic crushed pieces that naturally fall individually, The discriminated material is subjected to blast sorting by the blast sorting means. On the other hand, in the wind power sorting method (for example, Patent Document 3), the material to be sorted is moved down from above in the air blown in the lateral direction from the blower, so that the lightweight material, intermediate weight material and weight in the material to be sorted are collected. An object is blown away by a blowing action, and each is separated according to a flight distance.

Japanese Patent Laid-Open No. 2002-224652 JP 2002-303575 A Japanese Patent Laid-Open No. 7-1455

However, the method for separating the waste plastic fragments has the following problems. That is, there is a problem of purity (sorting accuracy) when the waste plastic crushed pieces are separated. In the above method, waste home electric appliances made of composite materials are collectively crushed, metals are separated and removed from the crushed pieces, and the remaining waste plastic crushed pieces are finally sorted by specific gravity, optical sorting or wind sorting. In this case, the waste plastic crushed pieces may be bent in a complicated manner and entangled with other different plastic waste pieces in the crushing process. In some cases, crushed pieces (hereinafter referred to as “combined materials”) in a state where they are bonded to each other may be generated. For this reason, the combined product cannot be separated into individual fragments by separating the combined state regardless of specific gravity separation, optical sorting, or wind sorting. The pieces were mixed with crushed pieces of different materials as they were combined, and this caused a decrease in the purity (sorting accuracy) of the waste plastic crushed pieces separated by material.
Therefore, in view of the above problems, the present invention has a technical problem to provide a pretreatment method that can perform material separation with high purity when the crushed raw material waste plastic fragment is subjected to material separation.

According to claim 1, the present invention provides
In the method of separating materials from waste plastic fragment materials when disassembling and crushing waste home appliances, etc. and separating them into valuable materials for recycling, the waste plastic fragments are thermally deformed at least before the material separation. The technical means of providing the pre-heating process which heats a waste plastic fragment at predetermined temperature is taken.

  The heating pretreatment step may be performed by a heating soaking step in which the waste plastic crushed pieces are immersed in a heating bath containing a liquid having a temperature for thermally deforming the waste plastic crushed pieces.

  The heating pretreatment step may be performed by a crushing step of supplying and crushing the waste plastic crushed pieces to a crushing means heated to a temperature at which the waste plastic crushed pieces are thermally deformed.

  According to the present invention, in the method of separating materials from waste plastic fragments obtained when disassembling and crushing waste home appliances, etc., separating them into valuable materials and recycling them, at least the material separation (plastic sorting step) Since a pre-heating process (heating process) for heating the waste plastic fragment at a predetermined temperature at which the waste plastic fragment is thermally deformed is provided in the previous process, the waste plastic supplied to the material separation (plastic sorting process) The crushed pieces are subjected to a stretching action (restoration action) due to thermal deformation due to the heating, and the waste plastic crushed pieces in a combined state are separated from each other and the shape is made simple. The plastic fragments can be separated from each other without being entangled with each other. Therefore, it is possible to separate the material waste plastic fragments with high purity.

This is a recycling process flow by disassembling and crushing waste home appliances in the present invention and separating them into valuable resources. It is the sectional side view which showed an example of the crushing process (crusher). It is the sectional side view which showed an example of the iron selection process (magnetic force sorter). It is the sectional side view which showed an example of the nonferrous metal sorting process (eddy current sorter). It is the figure which showed Example 1 "high temperature immersion method" in a heating pre-processing process (heating process). It is a sectional side view of the high temperature crushing apparatus which showed Example 2 "high temperature crushing method" in a heating pre-processing process (heating process). 1 is a side sectional view of a specific gravity sorting apparatus showing Example 1 “specific gravity sorting method” in a plastic sorting process. FIG. It is a sectional side view of the optical sorting device which showed Example 2 "optical sorting method" in a plastic sorting process.

  Hereinafter, an embodiment will be described with reference to FIGS. 1 to 8 as to a pretreatment method when separating waste plastic fragments of the present invention.

  The present invention is a waste plastic product in which plastic parts made of a plurality of different materials (types) are used, for example, waste home appliances such as washing machines, refrigerators, televisions, air conditioners, office automation equipment, plastic bottles, toys, and automobile parts. It can be applied when recycling etc. Hereinafter, in the embodiment of the present invention, a description will be given taking a waste home appliance as an example. FIG. 1 is a recycle processing flow to which the present invention is applied when disassembling and crushing waste home appliances, sorting them into valuable materials and recycling them. Hereinafter, the recycle flow will be described in steps (processes) (see FIG. 1).

Step 1 (hand sorting process):
Step 1 is a manual sorting process. The manual sorting process involves manual recycling of specific parts that can be recycled by itself, such as waste home appliances, refrigerant freons, cathode ray tubes, liquid crystal units, batteries, toner cartridges, fluorescent tubes, glass, metal plates, and glass plates. It is a process of disassembling and separating and removing. Through this manual sorting process, the waste home appliances become waste mainly plastic parts.

Step 2 (crushing process):
Step 2 is a crushing process. The crushing process is a process of removing specific parts in the manual sorting process (step 1) and crushing waste mainly including remaining plastic parts. The waste can be crushed using a known crusher, and for example, the crusher 1 shown in FIG. 2 can be used. As shown in FIG. 2, the crusher 1 includes a cutter-type rotary crushing blade 4 in which a rotating shaft 3 is provided horizontally inside a machine body 2, and a fixed blade 5 is disposed opposite thereto. To do. In addition, a raw material supply port 6 and a crushed material discharge port 7 are provided in the upper and lower parts of the machine body 2, respectively. Further, a discharge screen 8 having a mesh hole of an arbitrary size is provided below the rotary crushing blade 4, and the size of the mesh hole can be about 6 mm in diameter, for example.

  When the crusher 1 configured as described above supplies raw material waste to the raw material supply port 6, the raw material waste is subjected to a shearing action between the rotary crushing blade 4 and the fixed blade 5. Scrap pieces such as plastics and metals that are sequentially crushed and crushed to a size of about 6 mm or less pass through the mesh holes of the discharge screen 8 and are discharged from the crushed material discharge port 7. The waste discharged from the crushed material discharge port 7 mainly consists of plastic pieces (waste plastic crushed pieces) and mixed with metal crushed pieces. In addition, what is necessary is just to change the magnitude | size of the said mesh hole suitably.

Step 3 (Iron sorting process):
Step 3 is an iron sorting process. The iron sorting step is a step of first separating and removing iron crushed pieces from the raw plastic crushed pieces mainly containing waste plastic crushed pieces discharged from the crushing step (step 2) and mixed with metal pieces. . The iron fragments can be separated and removed using a known magnetic separator. FIG. 3 shows an example of the magnetic separator 9. The magnetic separator 9 is composed of a belt conveyor 10 disposed laterally so as to sequentially transfer the raw material crushed pieces. The belt conveyor 10 constitutes a magnet pulley 10b that drives the conveyor belt 10a. The magnet pulley 10b may be, for example, one having a magnetic force of about 6000 gauss on the surface of the conveyor belt 10a. A scraper 11 is disposed below the magnet pulley 10b. The scraper 11 scrapes off the iron fragments remaining adsorbed on the surface of the conveyor belt 10a. Further, a partition plate 12 is disposed on the side of the belt conveyor 10 on the conveyance end side so that the iron fragment pieces that are separated and dropped by the magnetic action of the magnet pulley 10b do not mix with the other fragment pieces. is there.

  The magnetic separator 9 configured as described above is configured such that when the raw material crushed pieces are transported by the transport belt 10a and discharged / dropped from the transport end portion, the iron crushed pieces are not discharged / dropped as they are. It is configured so that it can be attracted to the surface of the conveyor belt 10a by the magnetic force action of the pulley 10b, conveyed to the back side of the conveyor belt 10a, and scraped and separated by the scraper 11. Thereby, an iron crushed piece and other crushed pieces (mainly waste plastic crushed pieces) can be separated (see FIG. 3).

Step 4 (non-ferrous metal sorting process):
Step 4 is a non-ferrous metal sorting process. The non-ferrous metal sorting step is a step of separating and removing non-ferrous metal crushed pieces (aluminum, etc.) from other crushed raw materials mainly composed of the remaining waste plastic crushed pieces separated in the iron sorting step (step 3). The separation and removal of the nonferrous metal fragments can be performed using a known eddy current sorter. FIG. 4 shows an example of the eddy current sorter 13. The eddy current sorter 13 is provided with a belt conveyor 13a horizontally arranged so as to sequentially transfer the other crushed pieces raw material, which is the product side crushed pieces sorted and discharged in step 3 (iron sorting step), and the belt A magnet rotating body 14 is provided at a position below a trajectory where the raw material is discharged and dropped from the conveyance end side of the conveyor 13a. Further, at the side position of the magnet rotating body 14, the nonferrous metal shredded pieces that fall by changing the fall trajectory R by the action of the magnet rotating body 14 and the nonferrous metal that falls along the falling trajectory R are dropped. A partition plate 15 for separating waste plastic crush pieces other than metal crush pieces is provided.

  The eddy current sorter 13 configured in this way conveys the other crushed pieces raw material (mixed nonferrous metal crushed pieces and waste plastic crushed pieces) by the belt conveyor 13a from the terminal portion to the magnet rotating body 14. When released upward, the non-ferrous metal fragment has an eddy current inside and has a magnetic field, the magnetic field and the magnetic field of the magnet rotating body 14 repel each other, and the non-ferrous metal fragment flits in the direction of arrow H, The waste plastic crushed pieces are configured to fall along the fall trajectory R. Thereby, the nonferrous metal crushed pieces can be separated and removed from the waste plastic crushed pieces (see FIG. 4). As described above, the crushed pieces after Step 1 to Step 4 (hand sorting, crushing, iron sorting, non-ferrous metal sorting) become waste plastic crushed pieces made of a plurality of materials. Note that the waste plastic crushed pieces may be appropriately passed through a known wind power sorter (such as a cyclone system) for the purpose of removing mixed dust and the like.

Step 5 (heating process): <heating pretreatment process>
Step 5 is a heating process. In the heating step, the waste plastic crushed pieces separated in the non-ferrous metal sorting step (step 4) in the previous step are heated at a predetermined temperature at which the waste plastic crushed pieces are thermally deformed, whereby the crushing in the crushing step (step 2). It is a step of separating the combined crushed pieces by extending each crushed piece by thermal deformation of a combined material in which the crushed pieces of different materials are bonded to each other by bending intricately by action and entangled with other different materials. . The heating step can be performed, for example, in Example 1 (FIG. 5) or Example 2 (FIG. 6).

Example 1 of heating process (FIG. 5):
Example 1 (FIG. 5) of the heating step is based on the “high temperature dipping method”. The high-temperature dipping method involves dipping waste plastic fragments in a liquid heated to an arbitrary heat deformation temperature within each heat deformation temperature range in consideration of the heat deformation temperature of various plastic materials. More specifically, as shown in FIG. 5, the high-temperature dipping method uses a liquid having a temperature that takes into account the heat deformation temperature of various plastic materials, for example hot water, into the dipping tank 16 and put it in a mesh container 17. The waste plastic crushed pieces G are immersed and stirred ((1) and (2) in FIG. 5).

  At this time, when the temperature of the hot water (liquid) is 90 ° C., for example, PET (polyethylene terephthalate resin), PS (polystyrene resin), ABS (which is a plastic material having a heat deformation temperature of 90 ° C. or less). ABS resin), PVC (vinyl chloride resin), PP (polypropylene resin) and PE (polyethylene resin) are thermally deformed and stretched. For this reason, about the said combination K which consists of a combination of the plastics of the said material, the extending | stretching effect | action arises by a thermal deformation, Thereby, the crushed pieces (Material A and Material B of (1) of FIG. 5) joined together. While being separated, the broken pieces that are bent in a complicated manner have a simple shape due to the stretching action and the restoring action. The waste plastic crushed pieces G that have been heated and separated in this way are taken out from the immersion tank 16 together with the mesh container 17 ((3) in FIG. 5). In addition, since the taken-out waste plastic crushed piece G is moist, it may be appropriately dried by a drying method.

  In the above description, the hot water temperature is set to 90 ° C., but the hot water (liquid) temperature may be set as appropriate based on the thermal deformation temperatures of the following plastic materials. About each thermal deformation temperature, PET (polyethylene terephthalate resin): 55 ° C to 70 ° C, PS (polystyrene resin): 70 ° C to 100 ° C, ABS (ABS resin): 90 ° C to 105 ° C, PVC (vinyl chloride resin) : 55 ° C to 80 ° C, PP (polypropylene resin): 45 ° C to 65 ° C, and PE (polyethylene resin): 55 ° C to 85 ° C. In addition, about PC (polycarbonate resin), since a heat deformation temperature is 115 degreeC-140 degreeC, when it carries out by the method of the following Example 2 about the waste plastic fragment which the said PC (polycarbonate resin) is mixed in Good.

Example 2 of heating process (FIG. 6):
Example 2 (FIG. 6) of the heating step is based on the “high temperature crushing method”. In the same way as described in the first embodiment, the high temperature crushing method takes into account the heat deformation temperature of various plastic materials, and heats the crushing means, for example, a pair of high temperature rotating rolls 18 to a heat deformation temperature range to crush waste plastic. By passing the piece G between the high-temperature rotating rolls 18, the crushed pieces of the combination K are separated and flattened to have a simple shape. As shown in FIG. 6, a specific high-temperature crushing device 19 using the high-temperature crushing method includes a pair of high-temperature rotating rolls 18 made of iron rolls 18a and 18b rotating in different directions and at different rotational speeds. And heating means 18c for heating the rolls 18a and 18b. Further, a belt conveyor 19a is provided for conveying raw material waste plastic crushed pieces between the rolls 18a and 18b.

  According to this high-temperature crushing method, the waste plastic crushed pieces G are supplied between the rolls 18a and 18b heated to an arbitrary heat deformation temperature by the belt conveyor 19a, and the peripheral speed difference due to the difference in the rotation speed between the rolls 18a and 18b. The bonded material K is decomposed and separated into a plurality of crushed pieces by the frictional action, the crushing action, and the heating and drawing action, and becomes flat and has a simple shape. In addition, the crushed pieces other than the combined material K, which are bent in a complicated manner, pass between the rolls 18a and 18b, and thus are similarly subjected to the peripheral speed differential frictional action, the crushing action, and the heating and drawing action, as described above. . According to the high temperature crushing method (high temperature crushing device 19), the iron rolls 18a, 18b can be heated to 100 ° C. or higher, so that the heat distortion temperature exceeds 100 ° C. and 115 ° C. to 140 ° C. It can be applied to the PC (polycarbonate resin) at ℃.

Step 6 (plastic sorting process):
Step 6 is a plastic sorting process. In the plastic sorting step, waste plastic fragments G consisting of fragments obtained by separating the combined material K by the heating step (step 5) of the previous step or those that have been bent in a complicated shape are classified by material. It is a process of separating. The plastic sorting process can be performed by, for example, Example 1 (FIG. 7) and Example 2 (FIG. 8) of the plastic sorting process.

Example 1 of plastic sorting process (FIG. 7):
Example 1 (FIG. 7) of the plastic sorting process is based on the “specific gravity sorting method”. As shown in FIG. 7, the specific gravity sorting device 20 using the specific gravity sorting method includes a water tank 21 that stores water, and a circulation device 22 that allows water on the upper surface side in the water tank 21 to flow from one side to the other side. And a supply belt conveyor 23 for supplying the raw material waste plastic crushed pieces G to the upstream side of the water tank 21 opening. Further, on the downstream side of the opening of the water tank 21, a discharge belt conveyor 24 is provided that conveys and discharges the plastic having a low specific gravity and floating in the water to the outside of the water tank 21. The circulation device 22 includes an outlet 24a of reflux water on the one side (upstream side) of the water tank 21, and a suction port 24b for sucking water in the water tank 21 on the other side (downstream side) of the water tank 21, A circulation path 24d is provided that communicates the ejection port 24a and the suction port 24b with the circulation pump 24c. The water tank 21 is provided with a partition at the bottom between the one side (upstream side) and the other side (downstream side), thereby forming a first separation tank 21a and a second separation tank 21b. is there. Discharge screw conveyors 21c and 21d for discharging waste plastic fragments that have settled and accumulated by specific gravity sorting to the outside of the water tank 21 are respectively provided on the bottom surfaces of the first and second separation tanks 21a and 21b. It is provided.

  The operation of the specific gravity sorting device 20 will be described (see FIG. 7). Waste plastic shredded pieces G made of a plurality of materials that are separated from each other without being joined and are simply shaped are supplied into the water tank 21 of the specific gravity sorting device 20 and supplied from the previous process. Depending on the specific gravity, it is divided into a plurality of materials. Specifically, the waste plastic crushed pieces G are supplied to one end side of the water tank 21 by a supply belt conveyor 23, and the waste plastic crushed pieces G supplied to one end side (upstream side) of the water tank 21 are made of individual materials. The first separation tank 21a and the second separation while being transferred to the other side (downstream side) of the water tank 21 along the flow of water in the water tank by the circulation device 22 while sinking due to the specific gravity and in a floating state The water is separated into three on the other side (downstream side) of the water surface of the tank 21b and the water tank 21.

  For example, when the material of the waste plastic crushed piece G is PVC, PS, ABS, PE and PP, the specific gravity sorting device 20 includes a PVC crushed piece (specific gravity) in the first separation tank 21a. 1.33-1.44) are separated, PS fragment (specific gravity 1.02-1.15) and ABS fragment (specific gravity 1.03-1.09) are separated in the second separation tank 21b, and the other side (downstream side) of the water surface of the tank 21. The PE fragments (specific gravity 0.90 to 0.98) and PP fragments (specific gravity 0.90 to 0.96) are separated. The separated PE crushed pieces and PP crushed pieces are discharged out of the water tank 21 by the discharge belt conveyor 24b, and the PVC crushed pieces separated into the first separation tank 21a are put out of the water tank 21 by the discharge screw conveyor 21c. Similarly, the PE crushed pieces and PP crushed pieces separated into the second sorting tank 21b are discharged out of the water tank 21 by the discharge screw conveyor 21d.

Characteristic action 1 of the present invention:
Waste plastic crushed pieces supplied to the specific gravity sorter 20 (plastic sorting step, Example 1) are joined to each other by thermal deformation and stretching action by heating in the heating step (step 5) of the previous step. Since the crushed pieces are separated from the state and have a simple shape, when the specific gravity is separated in the water tank 21, the crushed pieces are reliably separated one by one and are not entangled with each other. For this reason, raw material waste plastic fragments can be separated with high purity.

  In addition, about the PS crushing piece and the ABS crushing piece discharged | emitted from the said 2nd separation tank 21b, in order to isolate | separate this further for every material, Example 2 (FIG. 8) "optical sorting method" of the plastics sorting process mentioned later Can be separated. Similarly, PE crushed pieces and PP crushed pieces discharged out of the water tank 21 by the discharge screw conveyor 21d can also be separated by the optical sorting method.

Example 2 of plastic sorting process (FIG. 8):
Example 2 (FIG. 8) of the plastic sorting process is based on the “optical sorting method”. The optical sorting device 25 according to the optical sorting method includes a belt conveyor 26 that transports and conveys the raw plastic fragment G as a raw material, and discharges and drops it from the end side, and the waste plastic fragment G falls from the end side. And an optical discriminating unit 27 that discriminates the material of the waste plastic fragment disposed at a position along the fall trajectory R. Furthermore, waste plastic crushed pieces are separated by a blast (air gun) for each determination material at a position below the optical determination unit 27 along the fall locus R based on the material determination process of the optical determination unit 27. A sorting unit 28 for sorting is also provided.

  The optical discriminating unit 27 irradiates light to an arbitrary optical detection position in the fall trajectory R, and detects each reflected light of the waste plastic fragment irradiated from the illumination unit 27a at the optical detection position. And a material discriminating unit 27c that discriminates the material of each waste plastic fragment based on the reflected light detected by the light receiving unit 27b. In addition, the classification unit 28 sequentially arranges a plurality of blast nozzles 28a, 28b, 28c, 28d, 28e, 28f, and 28g that blast toward the fall locus R at intervals, and Each accommodating part 29a, 29b, 29c, 29d, 29e, 29f, 29g which accommodates the waste plastic fragment removed from the fall locus R by the blast of the wind nozzles 28a, 28b, 28c, 28d, 28e, 28f, 28g is also arranged. Set up. Between any of the blast nozzles 28a, 28b, 28c, 28d, 28e, 28f, 28g and the material discrimination unit 27c, any one of the blast nozzles 28a is based on a material discrimination signal from the material discrimination unit 27c. , 28b, 28c, 28d, 28e, 28f, and 28g, a high-pressure air supply unit 30 that outputs a blast driving signal is also provided.

  The operation of the light sorting device 25 will be described (see FIG. 8). Waste plastic fragments G made of a plurality of materials, which are supplied from the previous process and separated into individual pieces without being joined, and in a simple shape, are sequentially discharged from the belt conveyor 26 of the light sorting device 25. Be dropped. Each waste plastic shredded piece discharged and dropped sequentially from the belt conveyor 26 is discriminated by the material discriminating unit 27 by detecting the reflected light of each waste plastic shredded piece, and a blast for each material based on the discrimination result Sorted. In the example of FIG. 8, the waste plastic crushed pieces G of raw materials are PC crushed pieces, PET crushed pieces, PS crushed pieces, ABS crushed pieces, PVC crushed pieces, PP crushed pieces and PE crushed pieces. In the case of a piece, the PC fragment is sorted into the accommodating part 29a by the blast action of the blast nozzle 28a, the PET fragment is sorted into the accommodating part 29b by the blast action of the blast nozzle 28b, and so on. In addition, the PS crushed pieces are sorted into the containing portion 29c, the ABS crushed pieces are sorted into the containing portion 29d, the PVC crushed pieces are sorted into the containing portion 29e, the PP crushed pieces are sorted into the containing portion 29f, and the PE crushed pieces are sorted into the containing portion 29g.

Characteristic action 2 of the present invention:
Waste plastic crushed pieces supplied to the light sorting device 25 (plastic sorting step, Example 2) are separated into individual pieces instead of being joined by the heating action of the heating step (step 5) of the previous step, and Since the shape is a crushed piece, the discrimination unit 27 can individually detect the reflected light from the crushed piece, and the crushed piece that is simply shaped does not cause irregular reflection or the like. Therefore, since the reflected light can be detected accurately and stably, the crushed pieces can be reliably separated one by one. For this reason, raw material waste plastic fragments can be separated with high purity.

DESCRIPTION OF SYMBOLS 1 Crusher 2 Machine 3 Rotating shaft 4 Rotating blade 5 Fixed blade 6 Raw material supply port 7 Crushed material discharge port 8 Discharge screen 9 Magnetic separator 10 Belt conveyor 10a Conveyor belt 10b Magnet pulley 11 Scraper 12 Partition plate 13 Eddy current sorter 13a Belt conveyor 14 Magnet rotating body 15 Partition plate 16 Immersion tank 17 Mesh container 18 High temperature rotating roll 18a Iron roll 18b Iron roll 18c Heating means 19 High temperature crushing device 19a Belt conveyor 20 Specific gravity sorting device 21 Water tank 21a First separation tank 21b Second separation Tank 21c Discharge screw conveyor 21d Discharge screw conveyor 22 Circulation device 23 Supply belt conveyor 24 Discharge belt conveyor 24a Discharge port 24b Suction port 24c Circulation pump 24d Circulation path 25 Light sorting device 26 Belt conveyor A 27 Optical discriminating section 27a Illuminating section 27b Light receiving section 27c Material discriminating section 28 Sorting section 28a Jet nozzle 28b Jet nozzle 28c Jet nozzle 28d Jet nozzle 28e Jet nozzle 28f Jet nozzle 28g Jet nozzle 29a housing section 29b Container 29c Container 29d Container 29e Container 29f Container 29g Container G Waste plastic fragment K Combined material R Falling locus

Claims (3)

  In the method of separating the waste plastic products, etc., separating them into valuable materials and recycling them, the waste plastic fragments are thermally deformed at least before the material separation. A pretreatment method for separating materials of waste plastic fragments, characterized by providing a pretreatment step for heating the waste plastic fragments at a predetermined temperature.   2. The waste plastic fragment according to claim 1, wherein the heating pretreatment step includes a heating immersion step of immersing the waste plastic fragment in a heating bath containing a liquid having a temperature for thermally deforming the waste plastic fragment. Pre-processing method when doing.   2. The waste plastic fragment according to claim 1, wherein the heating pretreatment step includes a crushing step of supplying and crushing the waste plastic fragment to a crushing means heated to a temperature at which the waste plastic fragment is thermally deformed. Pre-processing method when doing.

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