JP4639645B2 - Method for removing foreign matter from waste plastic - Google Patents

Description

  The present invention relates to a method for removing foreign substances in waste plastic when reclaiming waste plastic to produce an ore reducing agent or a solid fuel.

  In recent years, a method of producing an ore reducing agent or a solid fuel from waste plastic has been studied as one solution for effective use of waste plastic. This is because recycling industrial waste plastics and general waste plastics has attracted attention for effective use of resources and reduction of carbon dioxide generation. In addition, waste plastics (containers collected separately) based on the “Act on Separate Collection and Recycling of Containers and Packaging (Act No. 112 of 1995)” (hereinafter referred to as the Containers and Packaging Recycling Law) Packaging waste plastic) and waste plastic (home appliance waste plastic) collected separately based on the “Recycling Law for Specific Home Appliances (Act No. 97 of 1998)” (hereinafter referred to as the Home Appliance Recycling Law) Forming a recycling-oriented society through recycling is regarded as socially important.

  One of the important factors in producing ore reducing agents and solid fuel from waste plastic is to maintain the heat value per unit weight of the product at a high level. This is because the higher the calorific value, the higher the performance when using ore reducing agent or solid fuel, and the higher the thermal efficiency.

  However, waste plastics collected separately under the Containers and Packaging Recycling Law (that is, waste containers and packaging plastic) and waste plastics separately collected according to the Home Appliance Recycling Law (that is, household appliances waste plastic) are added to the original plastic. In addition to various additives (so-called fillers) such as flame retardants and extenders, iron, aluminum, glass, etc. derived from mixing of empty cans, empty bottles, etc. due to poor separation, or disassembly failures due to integral molding Many foreign substances are mixed in.

  Various efforts have been made to remove these foreign substances in the process of producing ore reducing agent or solid fuel to recycle waste plastic.

  Specifically, as a pretreatment of the manufacturing process, iron was separated by a magnetic separator, stainless steel and aluminum were separated by a metal separator, and glass and ceramics were separated by a wind separator. In addition, when waste plastic is melted and dissolved, or when it is partially pyrolyzed and oiled, there have been contrivances such as combining a filtration step and a centrifugation step.

  For example, Patent Document 1 discloses a technique for removing foreign substances by combining a centrifugal separator in an oil plasticizing process of waste plastic. Patent Document 2 discloses a technique for filtering a heated and melted plastic, and Patent Document 3 discloses a technique for removing foreign substances by filtering waste plastic in a solvent. .

  Furthermore, Patent Document 4 and Patent Document 5 disclose a technique for performing magnetic sorting and wind sorting as pre-processing of the container and packaging waste plastic recycling process, and Patent Document 6 discloses a combination of a magnetic separator and a non-ferrous separator. Has been. Patent Literature 7 and Patent Literature 8 disclose a combination of a magnetic separator and an eddy current separator as a household appliance waste plastic treatment process. Further, Patent Document 9 discloses a technique for separating foreign matter using an inclined vibration sorting deck.

  As described above, there are numerous techniques for separating foreign substances in waste plastic. However, when producing ore reducing agents and solid fuels from waste plastics, it is difficult to handle the removal of foreign substances by centrifugation or filtration because a significant decrease in viscosity cannot be expected due to thermal decomposition like oily conversion. . Further, when the waste plastic is dissolved in the solvent, a large amount of solvent is required, which is economically disadvantageous.

For this reason, in the process of producing ore reducing agents and solid fuels, it is common to remove foreign substances by crushing magnetic force or wind separation after crushing as part of the pretreatment, but this prevents foreign substances from being caught in waste plastic. In order to increase the separation efficiency, it is necessary to crush waste plastic from several mm to several tens of mm in a crusher. For this reason, there exists a fault that the damage of the cutter of a crusher is remarkable.
JP 2002-180068 A Japanese Patent Laid-Open No. 11-70588 JP 2000-226469 A Japanese Patent Laid-Open No. 2001-232633 Japanese Patent Laid-Open No. 8-120285 Japanese Patent Laid-Open No. 10-1680 JP-A-6-226242 Japanese Patent Laid-Open No. 6-106091 JP 2000-167833 A

  The present invention solves the above problems and eliminates the use of a solvent and reduces the load on the waste plastic crusher when removing foreign substances in the process of producing ore reducing agent or solid fuel from waste plastic. An object of the present invention is to provide a method for efficiently removing foreign matter.

The inventor has conducted intensive research on a technique for removing foreign substances in waste plastic. As a result, the waste plastic is heated and melted by the heating and melting step, is dechlorinated made in the heating and melting step, then cooled in the cooling step, when its in the cooling step and solidified is made, then ground, thermal plastic and foreign matter It has been found that plastics and foreign substances are easily separated due to the difference in shrinkage rate and the poor conformity of the interface. Accordingly, the waste plastic is heated, then solidified with cooling, and then performed to remove the foreign substances after pulverization, easily remove foreign substances in the waste plastics. The present invention has been made based on such findings, the waste plastic is heated and melted by the heating and melting process, dechlorination is performed in the heating and melting step, then cooled in the cooling step, in the cooling step solidification is performed, then the removal of the foreign matter carried out after grinding, in the following simply referred removed.

That is, the present invention provides a foreign matter removing method of waste plastics to remove foreign matter in the waste plastics, waste plastics heated and melted by heating and melting step, dechlorination is performed in the heating and melting step, then it cooled in the cooling step its in the cooling step and solidified is made, then a foreign matter removing method of waste plastics which performs removal of the foreign matter removed by after grinding.

According to the invention, in the foreign matter removing method of waste plastics to remove foreign matter in the waste plastics, waste plastics heated and melted by heating and melting step, dechlorination is performed in the heating and melting step, then, an intermediate removal of foreign matter deeds, and further cooled in the cooling step, its in the cooling step and solidified is made, then a foreign matter removing method of waste plastics which performs removal of the foreign matter removed by after grinding.

Further, the present invention relates to a foreign matter removal method in waste plastic for removing foreign matter in waste plastic, after preliminarily removing the foreign matter in waste plastic , heating and melting in the heating and melting step, and dechlorination in the heating and melting step. is made, then cooled in the cooling step, its in the cooling step and solidified is made, then a foreign matter removing method of waste plastics which performs removal of the foreign matter removed by after grinding.

Further, the present invention relates to a foreign matter removal method in waste plastic for removing foreign matter in waste plastic, after preliminarily removing the foreign matter in waste plastic , heating and melting in the heating and melting step, and dechlorination in the heating and melting step. is made, then, subjected to intermediate removal of foreign matter, and further cooled in the cooling step, its in the cooling step and solidified is made, then a foreign matter removing method of waste plastics which performs removal of the foreign matter removed by after grinding.

In the foreign matter removal method of the present invention, that the method of performing the dividing removed by the foreign matter after the crushing, magnetic separation method is one or more method selected from the eddy current sorting and wind sorting Is preferred.

  Moreover, it is preferable that the method for preliminarily removing foreign substances is one or more methods selected from among a magnetic selection method, an eddy current selection method, and a wind force selection method. Furthermore, it is preferable that the method for performing intermediate removal of foreign substances is one or more methods selected from a filter selection method, a centrifugal separation method, and a sedimentation separation method.

According to the present invention, the following excellent effects (1) to (4) can be obtained.
(1) Eliminates foreign substances from waste plastics efficiently by simple means without using a solvent, and uses the waste plastics as a raw material, which generates fine solid fuel and ore reducing agent with high calorific value and excellent combustibility Can be manufactured.
(2) Because it is possible to convert waste plastics containing chlorine-containing plastics into processed plastics that do not substantially contain chlorine, it is possible to produce non-polluting solid fuels and ore reducing agents from waste plastics. it can.
(3) Since it is possible to convert waste plastics containing chlorine-containing plastics into processed plastics that do not substantially contain chlorine, the processed plastics obtained by the present invention can be used in blast furnaces, boilers, kilns, cupolas, coke ovens. Can be used as an ore reducing agent, solid fuel, raw material, and the like, and chemical erosion of the inner wall refractory of the furnace by chlorine or a chlorine compound can be prevented.
(4) Reduce the load on the crusher and extend the tool life.

  In addition, the foreign matter removing method of the present invention enables a large amount of waste plastic to be processed, and is excellent in economic efficiency.

  The present invention heats waste plastics, containers and packaging materials contained in municipal waste, industrial waste, general waste, etc., and waste plastics generated in the process of dismantling electrical appliances, automobiles, etc., to produce solid fuel and ore This is a foreign matter removal method suitable for producing a reducing agent.

  For the present invention, Waste plastic, II. Heat treatment process, III. Cooling and solidification process, IV. Crushing process, V. Foreign matter removal process will be described in more detail in this order.

I. Waste plastic:
Waste plastics that are the subject of the present invention, that is, waste plastics that are raw materials in the present invention include waste plastics and container packaging materials contained in municipal waste, industrial waste, general waste, etc., and dismantling of electrical products, automobiles, etc. Examples include waste plastics generated in the process. Moreover, a container packaging waste plastic and a household appliance waste plastic can be used.
Specifically, polyolefins such as polyethylene and polypropylene, polyvinyl chloride, polyvinylidene chloride, chlorinated polyethylene, polystyrene, polyethylene terephthalate, polycarbonate, nylon and other thermoplastic resins and thermosetting resins are all applicable. Any one of these waste plastics can be used, or two or more of them can be used.

  The shape and size of the waste plastic to be heat-treated may be roughly crushed, and a size of about 10 cm on a side is sufficient. General waste plastic does not need to be crushed again and can be processed as it is collected. Film, sheet, and fiber waste plastics can be processed as they are. Of course, fine pulverization may be performed, but in this case, the cost required for pulverization increases.

Further, foreign substances in the waste plastic may be removed (hereinafter referred to as preliminary removal) before the heat treatment step described in II below. This preliminary removal preferably employs one or more sorting methods selected from magnetic sorting, eddy current sorting, and wind sorting, as with the removal after pulverization .

II. Heat treatment process:
In the heat treatment step, for example, waste plastic is heated in a temperature range of 200 to 400 ° C., more preferably 250 to 340 ° C. in a heating container. By heating within the temperature range of 200 to 400 ° C., the waste plastic melts and can be dechlorinated. The heat treatment may be a batch type or a continuous type. An intermediate type such as batch switching may also be used.

  The heat treatment time is preferably 10 minutes to 30 hours. When the heat treatment time is less than 10 minutes, it becomes difficult to control the temperature in the heating container, and the dechlorination rate of the waste plastic decreases. On the other hand, when the heat treatment time exceeds 30 hours, the treatment efficiency is lowered and it is not economical. In the heat treatment, a heat medium may be allowed to coexist.

The heat treatment is preferably performed in a non-oxidizing atmosphere. Examples of the non-oxidizing atmosphere include N ₂ and Ar. N ₂ may exhibit a reducing action depending on conditions such as temperature and catalyst, but does not act as a reducing gas at the temperature of the heat treatment (200 to 400 ° C., particularly 250 to 340 ° C.).

  In addition, before the cooling and solidification step described in III below (that is, during the heat treatment described in II or after the heat treatment is completed), removal of foreign matters in the waste plastic (hereinafter referred to as intermediate removal). ) May be performed. This intermediate removal is preferably one or more methods selected from a filter selection method, a centrifugal separation method and a sedimentation separation method.

  The filter selection method, the centrifugal separation method, and the sedimentation separation method are respectively a method for separating and removing foreign matters using a filter, a method for removing foreign matters by centrifugation, and a method for removing foreign matters by sedimentation.

III. Cooling and solidification process:
The molten waste plastic after the heat treatment (hereinafter referred to as molten plastic) is solidified by cooling. Preferably, the molten plastic is cooled and solidified by supplying a fixed amount of the molten plastic to the belt cooler by a molten plastic conveying device. The amount of heat removed is calculated from the amount of enthalpy between the temperature after heat treatment and the temperature until fully solidified, and the treatment speed.For example, if waste plastic from containers and packaging is included, the center temperature after cooling is It is sufficient to control the temperature to about 110 ° C. before the pulverization step described in IV.

IV. Grinding process:
It is preferable that the molten plastic solid (hereinafter referred to as a plastic processed product) that has undergone the cooling and solidifying step is pulverized so as to have a predetermined particle size. The pulverization of the plastic treated product can be performed very easily as compared with the pulverization of the untreated waste plastic. That is, the processed plastic can be pulverized by any type of pulverizer, and as the pulverizer, for example, a jaw crusher, a roll crusher, a jet mill, a ball mill, a centrifugal mill, a hammer mill, or the like can be used.

  In particular, a pulverizer of a type (for example, a hammer mill) that pulverizes by applying an impact to a processed plastic product has good separability between the processed plastic product and foreign matter after pulverization. The particle size after pulverization is not particularly limited as long as it is a size that can effectively separate foreign matters in the foreign matter removing step described in V below, but generally 10 mm or less is appropriate.

V. Foreign matter removal process:
Particles of plastic processed material after milling, metal, glass, you divided by separating foreign matters ceramics or the like. Dividing this removed by the heating and melting, dechlorination, cooled, and solidified, so carried out after the grinding, due to the conformability of poor differences and interfacial thermal shrinkage of the plastic and the foreign matter easily remove foreign substances from the plastic This is an essential step in the present invention. Matako dividing removed by the the magnetic separator, an eddy current sorting is preferable to employ one or more sorting selected from air classifiers. Magnetic sorting is a technique for separating magnetic materials such as iron by an electromagnet. Eddy current sorting is a technique for separating metals such as aluminum, copper, zinc, etc., by the use of electromagnetic induction force when eddy currents are generated. In addition, wind sorting is a method of separating plastic processed products with a specific gravity of approximately 1 from glass, ceramics, etc. with a specific gravity of 1.2 or more, utilizing the difference in specific gravity and shape.

It is may be further finely pulverized plastics treated after performing the dividing removed by the foreign matter after grinding. The particle size may be determined according to the use of the plastic processed product. Combustion of raw fuel such as ore reducing agent such as iron ore (that is, reducing agent of vertical furnace producing pig iron such as blast furnace), boiler and kiln, etc. by adjusting the particle size so that it becomes a predetermined particle size It can be used as a fuel for fuel, cupola, and coke oven. Moreover, it can be used as a solid fuel in addition to the applications described above.

[Invention Example 1]
Waste plastic collected from municipal waste containers and packaging (chlorine content 2.3% by mass) in the city is crushed to about 1 cm on a side, and then 10 kg of water-sealed spill tube 3, heating device 4, stirrer shown in FIG. The mixture was charged in a heating vessel 1 having an internal volume of 50 liters equipped with a stirring blade 5 and a rotary drive device 6 and treated at 320 ° C. for 1 hour in an N ₂ atmosphere. The pH of the water seal water 7 was 2 or less, and chlorine ions were detected.

  Thereafter, the contents were extracted and cooled to room temperature, and then a sieve with a round hole having a diameter of 9 mm was attached to a hammer mill type pulverizer manufactured by Horai Iron Works, and pulverized for about 1 hour. About 820 g of the pulverized product was recovered. This pulverized product is called “treated waste plastic”.

  The ash content was measured by firing the treated waste plastic (at 625 ° C. in air for 4 hours) and found to be 3.94% by mass. The aluminum content in the ash determined by a calibration curve method using fluorescent X-rays was 11.5% by mass.

Further the processed waste plastics 230g with Kanetekku Ltd. Aluminum sorter due to eddy currents sorting, was performed dividing removed by the foreign matter after grinding, fusion-bonded 2g of aluminum and plastic has been removed. Calcining the processed waste plastics after performing the dividing removed by the foreign matter (625 ° C. in air, 4 hours) to was measured ash content was 3.88 wt%. The aluminum content in the ash was 5.6% by mass. The chlorine content was 0.45% by mass. This is referred to as Invention Example 1.

For Inventive Example 1, a calculating the amount of aluminum contained in the front of the treated waste plastics 100g performing dividing removed by the foreign matter after grinding 0.453g (= 100 × 0.0394 × 0.115 ). Further, it is calculating the processed waste plastics aluminum amount contained in 100g after performing the foreign matter removing removed by the 0.217g (= 100 × 0.0388 × 0.056 ). Therefore aluminum removal rate of which has been removed by the removal removed by the foreign matter is 52.1% (= 100 × [0.453-0.217 ] ÷ 0.453).

Moreover, in order to investigate the calorific value of the treated waste plastic from which the foreign matter after grinding was removed in Invention Example 1, the total calorific value was determined in accordance with JIS M8814: 2003. As a result, the total calorific value of the treated waste plastic of Invention Example 1 was 3.63 × 10 ⁷ J / kg (8670 kcal / kg).

[Invention Example 2]
Waste plastic containers and packaging waste plastic collected in the city different from Invention Example 1 (chlorine content 2.5% by mass) is pulverized to about 1 cm, then mixed well and partly taken out, air at 625 ° C for 4 hours When ash content was measured by baking in, it was 5.02 mass%. The aluminum content in the ash was 11.5% by mass.

2 kg of waste plastic crushed to about 1 cm, water-sealed outflow pipe 3 shown in FIG. 2, heating device 4, stirrer (stirring blade 5, rotational drive device 6), and 50 liters of internal volume with Y-strainer 10 as external filtration equipment After charging in the heating container 1 and treating at 320 ° C. for 1 hour in an N ₂ atmosphere, the gear pump 9 was started as a circulation pump, and intermediate removal was performed by performing filtration for 30 minutes. The eye opening of the Y-type strainer 10 was 5 mm. The pH of the water seal water was 2 or less, and chlorine ions were detected.

  Thereafter, the contents were extracted and cooled to room temperature, and then a sieve with a 9 mm eye opening (circular hole) was attached to a hammer mill type grinder manufactured by Horai Iron Works, and pulverized for about 1 hour. About 750 g of the pulverized product was recovered.

  The ash content was measured by firing the pulverized product in air at 625 ° C. for 4 hours, and it was 3.88% by mass. The aluminum content in the ash was 7.19% by mass.

The processed waste plastics 230g with Kanetekku Ltd. Aluminum sorter due to eddy currents sorting was performed dividing removed by the foreign matter after grinding. By calcining the processed waste plastics after performing the dividing removed by the foreign matter in 4 hours in air at 625 ° C., was measured ash content was 3.86 wt%. The aluminum content in the ash was 5.4% by mass. The chlorine content was 0.42% by mass.

The amount of aluminum contained in 100g of waste plastic before intermediate removal was 0.577g (= 100 x 5.02 / 100 x 11.5 / 100, and aluminum contained in 100g of plastic after intermediate removal and before removal after crushing. Is 0.279g (= 100 × 3.88 / 100 × 7.19 / 100), and the aluminum contained in 100g of plastic after removal after grinding is 0.208g (= 100 × 3.86 / 100 × 5.4 / 100) .

Accordingly, the aluminum removal rate in the intermediate removal is 80.8% {= (0.577−0.279) / (0.577−0.208) × 100}, and the aluminum removal rate in the removal after grinding is 19.2% {= (0.279−0.208) / (0.577− 0.208) × 100}. The aluminum removal rate by intermediate removal and removal after grinding is 64.0% {= (0.577−0.208) /0.577×100}.

[Invention Example 3]
After pulverizing municipal waste containers and packaging waste plastic (chlorine content 2.5 mass%) collected in the same city as Invention Example 2 to about 1 cm, using an aluminum sorter manufactured by Kanetec Corporation using the eddy current sorting method The foreign matter was preliminarily removed. The ash content was measured by calcining the plastic after removing aluminum in air at 625 ° C. for 4 hours, and it was 4.95% by mass. The aluminum content in the ash was 8.35% by mass.

1 kg of waste plastic crushed to about 1 cm is charged into a water-sealed outflow pipe 3, a heating device 4, a heating device 4, a heating vessel 1 having an internal volume of 50 liters equipped with a stirrer (stirring blade 5, rotary driving device 6), and N ₂ Treated at 320 ° C. for 1 hour in an atmosphere.

  The pH of the water seal water was 2 or less, and chlorine ions were detected.

  Thereafter, the contents were extracted and cooled to room temperature, and then a sieve with a 9 mm eye opening (circular hole) was attached to a hammer mill type grinder manufactured by Horai Iron Works, and pulverized for about 1 hour. About 850g of crushed product was recovered.

The processed waste plastic 230g was carried out by dividing removed by the foreign matter by using the Kanetekku Co., Ltd. aluminum sorting machine. By calcining the processed waste plastics after performing the dividing removed by the foreign matter in 4 hours in air at 625 ° C., was measured ash content was 3.95 wt%. The aluminum content in the ash was 6.32% by mass. The chlorine content was 0.46% by mass.

Aluminum contained in plastic 100g before preliminary removal is 0.577g (= 100 × 5.02 / 100 × 11.5 / 100), also after the preliminary removal, was contained in plastic 100g before removal after pulverization aluminum Is 0.413 g (= 100 × 4.95 / 100 × 8.35 / 100), and the aluminum contained in 100 g of plastic after removal after pulverization is 0.250 g (= 100 × 3.95 / 100 × 6.32 / 100) .

  Therefore, the aluminum removal rate in the preliminary removal is 50.2% {= (0.577−0.413) / (0.577−0.250) × 100}, and the aluminum removal rate in the necessary removal is 49.8% {= (0.413−0.250) / (0.577−0.250) × 100}. The aluminum removal rate by preliminary removal and necessary removal is 56.7% {= (0.577−0.250) /0.577×100}.

[Invention Example 4]
After pulverizing municipal waste containers and packaging waste plastic (chlorine content 2.5 mass%) collected in the same city as Invention Example 2 to about 1 cm, using an aluminum sorter manufactured by Kanetec Corporation using the eddy current sorting method The foreign matter was preliminarily removed. The ash content was measured by calcining the plastic after removing aluminum in air at 625 ° C. for 4 hours, and it was 4.95% by mass. The aluminum content in the ash was 8.35% by mass.

2 kg of waste plastic crushed to about 1 cm, 50 liters with a Y-strainer 10 as a water-sealed outflow pipe 3, a heating device 4, a stirrer (stirring blade 5, rotary drive device 6) and an external filtration device shown in FIG. Was heated in a N ₂ atmosphere at 320 ° C. for 1 hour, then the gear pump 9 was started as a circulation pump, and intermediate removal was performed by filtering for 30 minutes. The eye opening of the Y-type strainer 10 was 5 mm.

  The pH of the water seal water was 2 or less, and chlorine ions were detected.

  Thereafter, the contents were extracted and cooled to room temperature, and then a sieve with a 9 mm eye opening (circular hole) was attached to a hammer mill type grinder manufactured by Horai Iron Works, and pulverized for about 1 hour. About 750 g of the pulverized product was recovered. The ash content was measured by calcining the pulverized product in air at 625 ° C. for 4 hours and found to be 3.65% by mass. The aluminum content in the ash was 6.88% by mass.

Was carried foreign matter removing removed by the this treated waste plastics 230g with Kanetekku Ltd. Aluminum sorter due to eddy currents sorting. By calcining the processed waste plastics after performing the dividing removed by the foreign matter in 4 hours in air at 625 ° C., was measured ash content was 3.46 wt%. The aluminum content in the ash was 5.94% by mass. The chlorine content was 0.44% by mass.

The aluminum contained in 100 g of plastic before preliminary removal was 0.577 g (= 100 × 5.02 / 100 × 11.5 / 100), and after preliminary removal, the aluminum contained in 100 g of plastic before intermediate removal was 0.413 g (= 100 x 4.95 / 100 x 8.35 / 100), and 0.251g (= 100 x 3.65 / 100 x 6.88 / 100) of aluminum contained in 100g of plastic after intermediate removal and before removal after grinding. Furthermore, the amount of aluminum contained in 100 g of plastic after removal after pulverization is 0.206 g (= 100 × 3.46 / 100 × 5.94 / 100).

Therefore, the aluminum removal rate in the preliminary removal is 44.2% {= (0.577−0.413) / (0.577−0.206) × 100}, and the aluminum removal rate in the intermediate removal is 43.7% {= (0.413−0.251) / (0.577−0.206) × 100}, the aluminum removal rate in the removal after pulverization is 12.1% {= (0.251−0.206) / (0.577−0.206) × 100}. The aluminum removal rate by preliminary removal, intermediate removal and removal after grinding is 64.3% {= (0.577−0.206) /0.577×100}.

[Comparative example]
As a comparative example, the calorific value of the treated waste plastic that was not removed after grinding was measured. That is, the total calorific value of the treated waste plastic before the removal after pulverization of Invention Example 1 was measured by the same procedure as that of Invention Example 1. As a result, the total calorific value of the treated waste plastic of the comparative example was 3.59 × 10 ⁷ J / kg (8590 kcal / kg).

In addition, as explained in Invention Example 1, the iron content and the aluminum content in the ash of the treated waste plastic of the comparative example (that is, the treated waste plastic not subjected to removal after pulverization ) are the iron content in the ash. The aluminum content was 8.3% by mass and the aluminum content was 11.5% by mass.

According to Invention Examples 1 to 4, it can be seen that foreign matter can be removed by subsequent treatment and removal after grinding by crushing about 1 cm without crushing the waste plastic before treatment to several mm to several tens of mm. Therefore, in this invention, the load of the waste plastic crusher can be reduced. Furthermore, in the present invention, a processed plastic product having a low chlorine content can be obtained.

Further, by comparing the invention example 1 with the comparative example, it can be seen that 52.1% of aluminum, which is a foreign material, can be removed by removal after pulverization , and a processed plastic product having an improved total heat generation can be obtained. In addition, according to Invention Example 2, it can be seen that the removal rate of aluminum as a foreign substance can be improved to 64.0% by performing intermediate removal before removal after pulverization . Further, according to Invention Example 3, it can be seen that the removal rate of aluminum as a foreign substance can be improved to 56.7% by performing preliminary removal before removal after pulverization . Furthermore, according to Invention Example 4, it can be seen that the removal rate of aluminum as a foreign substance can be improved to 64.3% by performing preliminary removal and intermediate removal before removal after pulverization .

It is sectional drawing which shows the example of a heating container and its incidental equipment typically. It is sectional drawing which shows typically the other example of a heating container and its incidental equipment.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Heating container 2 Waste plastic 3 Water seal type outflow pipe 4 Heating device 5 Stirring blade 6 Rotation drive device 7 Water seal water 8 Extraction valve 9 Gear pump
10 Y-type strainer

Claims (5)

In the foreign matter removal method of the waste plastics to remove foreign matter in the waste plastics, the waste plastic is heated and melted by the heating and melting process, dechlorination is performed in the heating and melting step, then cooled in the cooling step, the cooling step foreign matter removing method of waste plastics solidification is performed, then and performing the removal of the foreign matter removed by after grinding in. In the foreign matter removal method of the waste plastics to remove foreign matter in the waste plastics, the waste plastic is heated and melted by the heating and melting process, dechlorination is performed in the heating and melting process, then, subjected to intermediate removal of foreign matter, further cooled cooled in step, the solidification in the cooling step is performed, then the foreign matter removing method of waste plastics and performing the dividing removed by the foreign matter after grinding. In the foreign matter removal method of the waste plastics to remove foreign matter in the waste plastics, after performing a preliminary removal of the foreign matter of the waste plastics, is heated and melted by the heating and melting process, dechlorination is performed in the heating and melting step, then , cooled in the cooling step, the solidification in the cooling step is performed, then the foreign matter removing method of waste plastics and performing the dividing removed by the foreign matter after grinding. In the foreign matter removal method of the waste plastics to remove foreign matter in the waste plastics, after performing a preliminary removal of the foreign matter of the waste plastics, is heated and melted by the heating and melting process, dechlorination is performed in the heating and melting step, then performs intermediate removal of foreign matter, further cooled in the cooling step, the solidification in the cooling step is performed, then the foreign matter removing method of waste plastics and performing the dividing removed by the foreign matter after grinding. Method of performing removal of the foreign matter removed by after the crushing, magnetic separation method, according to claim 1, characterized in that the one or more method selected from the eddy current sorting and wind sorting 5. A method for removing foreign matter in waste plastic according to any one of 4 above.

Images