JPH05293827A - Separating method for foreign substance from plastic waste - Google Patents

Abstract

PURPOSE:To separate foreign substances from a plastic waste matter effectively by providing a screw transfer element on a filtrating strainer to thereby exhaust filtrated residuals and by providing the strainer close to the blade outer periphery of the transfer element in the case of liquefying plastic waste matters and separating foreign substances therefrom through filtration. CONSTITUTION:Waste plastics are liquefied through a solvent or heating and then filtrated by a strainer 3. Solid matters remained on the strainer 3 are discharged outward by means of a screw transfer element 2. At this time, the strainer 3 is made into a shape which can wrap the blade 5 of the transfer element 2 in a manner not causing interstices between the strainer 3 and the transfer element 2 and thus enabling the remainders to be exhausted therefrom completely. This method is particularly effective to styrene foam waste matters.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for separating foreign matter from plastic waste mixed with foreign matter.

[0002]

2. Description of the Related Art Garbage is increasing on a global scale. In particular, plastic is extremely troublesome because it does not corrode and disappear.

Foreign substances are inevitably mixed in the plastic waste because it is dust. It will be economically unprofitable if it is manually sorted and separated. The point of plastic waste disposal is how to efficiently collect and dispose of only plastic from the vast amount of waste. This problem cannot be avoided whether the waste plastic is oiled or reused. No effective method has yet been established for this sort separation.

[0004]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems, and it is an object of the present invention to provide a method for efficiently separating a plastic component from a plastic waste containing a foreign substance.

[0005]

The above-mentioned problems can be solved by the following means. 1. It is a method to separate the undissolved residue and the liquid plastic content from the plastic waste by liquefying it by dissolving it in a solvent or liquefying it by heat melting and filtering it. A screw transfer element is provided on the strainer, and the strainer is formed into a close shape along the outer periphery of the blade of the transfer element, and the filtration residue remaining on the strainer is screwed and discharged by the transfer element. A method for separating foreign matter from plastic waste, which comprises: 2. A method for separating undissolved foreign matter and liquid plastic content by heating, liquefying, and filtering the plastic content of plastic waste mixed with foreign matter, in which a screw transfer element is provided on the strainer for filtration. Is a shape closely contacted with the outer circumference of the blade of the transfer element, and the filtration residue remaining on the strainer is screwed and discharged by the transfer element to remove foreign matter from the plastic waste. How to separate.

[0006]

The present invention has the following constitution. That is, the plastic in the waste plastic is liquefied by dissolving it in a solvent, or liquefied by heating and melting, and filtered by a strainer to separate from the solid residue that does not liquefy, and the solid matter remaining on the strainer It is designed to be discharged to the outside by a screw transfer element. At this time, the strainer has a close shape along the outer circumference of the blade of the transfer element,
In other words, the shape is such that the blades of the transfer element are wrapped so that there is no gap between the transfer element and the transfer element, and the residue can be discharged to the outside without any residue. In the case of liquefying the resin or in the case of melt liquefaction, the melt liquefaction temperature is about 300 to 500 ° C., although there are some which do not liquefy depending on the type of plastic. Foreign substances such as ordinary wood chips, iron chips, and food waste are almost solid at this temperature, and there is a clear difference in properties from liquefied plastic, and solid-liquid can be clearly separated. In the case of this method, the strainer and the transfer element in the area where the solid-liquid is separated need to be kept at the liquefaction temperature of the resin, but it is not always necessary to keep the temperature at this temperature. For example, the temperature may be gradually increased from the inlet to have a slope so as to reach the liquefaction temperature. If the resin is dissolved in a solvent, then there is no solvent common to all resins. It is necessary to use properly according to the type of resin. The method is most effectively applied to styrofoam waste. In this case, the solvent is preferably styrene monomer, benzene, toluene, xylene or the like. Above all, a styrene monomer solution is preferable.

[0007]

The method of the present invention will be described with reference to the drawings. 1 to 5 are diagrams for explaining a representative example of the mechanism of the present invention, and FIG. 4 is a diagram for explaining the characteristics of the strainer of the mechanism of FIGS. 1 to 5, is a cylinder of a screw conveyor, is a screw transfer element,
Is a strainer for filtration, is a tank for storing the filtrate,
Is a blade of the screw transfer element, is a heater for heating the cylinder, and is a discharge port for discharging the solid residue.
The shape of the vanes of the cylinder and the transfer element can be appropriately used from a straight shape (FIG. 1) to a tapered shape (FIGS. 2 and 3) as shown in the figure. As shown in Fig. 4, the shape of the strainer for filtration is such that there are no gaps along the outer circumference of the blades of the transfer element, and there is no residue left on the strainer. It can be sent and discharged. From the charging port, plastic waste in a state where liquefied plastic is mixed with solid foreign matter is charged. The waste contained in the screw conveyer is transferred to the discharge port by the transfer element, while the solid content and the filtered solid residue are transferred, while the liquefied product is filtered by the strainer and stored in the tank. FIG. 5 shows the case where the plastic is liquefied by heat melting, the cylinder is heated by the heater, and the portion with the strainer is heated to a temperature of 300 to 500 ° C. at which the resin is liquefied.
The injected waste is gradually heated while being transferred in the cylinder, and the plastic content is completely liquefied in the portion where the strainer is present, and is filtered here. The remaining solid residue is transferred to the discharge port by the transfer element.
In the case of this example, it is also possible to appropriately provide a gas vent hole between the charging port of the cylinder and the liquefaction zone to take out the gas generated before the liquefaction. Vinyl chloride resin generates hydrogen chloride gas at around 200 ° C., but dehydrochlorination treatment can be performed before liquefaction by providing a gas vent hole in the portion where the resin is heated to around this temperature. Next, an example applied to actual waste plastic will be described. Example 1 The apparatus shown in FIG. 2 was used. Styrofoam waste with rice grains attached was finely crushed, and then liquefied with a styrene monomer solution was charged from a charging port. The liquid Styrofoam solution was filtered from the strainer, and the residue of rice grains was discharged from the discharge port. The filtrate could then be charged to the pyrolysis furnace and converted to hydrocarbon oil. Example 2 Using the apparatus shown in FIG. 5, as waste plastic, a mixture of styrene foam, polyethylene, urethane, vinyl chloride, and ABS resin was used. The conveyor had a temperature gradient from the entrance to the central part, and the central part was heated to a temperature of 400 to 450 ° C. The free-flowing hot-melt, liquid plastic was filtered from the strainer section. On the other hand, a carbonized solid residue was discharged from the discharge port. The filtered liquid changed to pudding when cooled to room temperature.

[0008]

Industrial Applicability As described above in detail, the present invention has a feature that foreign substances can be economically removed from plastic waste, and greatly contributes to the industrialization of plastic waste treatment.

[Brief description of drawings]

FIG. 1 is an explanatory view of the mechanism of the present invention when a solvent is used.

FIG. 2 is an explanatory view of the mechanism of the present invention when a solvent is used.

FIG. 3 is an explanatory view of the mechanism of the present invention when a solvent is used.

FIG. 4 is an explanatory diagram of a strainer of the present invention.

FIG. 5 is an explanatory view of the mechanism of the present invention when heat melting is used.

[Explanation of symbols] Cylinder of screw conveyor, screw transfer element, strainer for filtration, tank for storing filtrate, screw vane of screw transfer element, heater for cylinder discharge solid residue Outlet

Claims (2)

[Claims] 1. A method of separating a plastic content from a plastic waste by liquefying it by dissolving it in a solvent, or liquefying it by heat melting, and separating an undissolved residue and a liquid plastic content by filtering. Therefore, a screw transfer element is provided on the strainer for filtration, and the strainer has a shape in close contact with the outer circumference of the blade of the transfer element to transfer the filtration residue remaining on the strainer to the transfer element. A method for separating foreign matter from plastic waste, which is characterized by screwing and discharging with a child. 2. A method for separating undissolved foreign matter and liquid plastic content by heating and liquefying the plastic content of plastic waste mixed with foreign matter, and filtering, wherein a screw transfer element is placed on a strainer for filtration. The plasticizer is characterized in that the strainer has a shape closely contacted along the outer circumference of the blade of the transfer element, and the filtration residue remaining on the strainer is screwed and discharged by the transfer element. A method of separating foreign materials from waste.