KR100998995B1 - How to recycle plastic waste - Google Patents

Abstract

The present invention relates to a method for regenerating plastic wastes obtained by pulverizing the collected plastic wastes, performing specific gravity selection, melting the sorted plastic wastes, deodorizing and discoloring to obtain pure resin powder. In the method of the present invention, a mixture of white kerosene is mixed with a pulverized product of plastic waste and melted to be converted into a low-viscosity liquid. After the activated clay was added to the low-viscosity melt of the deodorized pulverized powder, the adsorbed colored impurities were adsorbed and decolorized.The deodorized and dissolved melt was stirred and cooled in another tank. In the first two-dimensional centrifugation step to separate and remove the solids of sulfuric acid deodorant or adsorptive decolorant, the gelled resin melt obtained by the first centrifugation was cooled to room temperature in another tank, and then normal hexane was injected into the gelled resin melt and stirred. The residue of white kerosene, a solvent present in the gelled resin melt, And dissolving the gelatinous resin melt containing normal hexane in which the kerosene residue was dissolved. The resin powder and the normal hexane are classified and the normal hexane is cooled and recovered.

Plastic waste, deodorization, bleaching, white kerosene, normal hexane.

Description

Plastic Waste Recycling Method {METHOD FOR RECYCLING OF PLASTIC WASTE}

The present invention relates to a method for recycling plastic waste, and in particular, to pulverize the collected general plastic waste, to perform specific gravity sorting, and to melt and classify the sorted plastic waste, to deodorize, decolorize and purify to obtain pure resin powder. It is about. Plastic materials of the plastic waste handled by the present invention include polyolefin resins such as polyethylene (PE), polypropylene (PP), and polyamide resins such as PA6, PA11, PA12, and PA610 among thermoplastic resins. Styrene-based resins in which the viscosity of the molten resin becomes high are excluded.

Plastic waste is usually sorted after collection and melted and recycled. However, the regeneration of plastic waste is only a product of a different form and rarely is recycled as a true pure water support fee. Examples of plastic wastes include waste bottles or containers for various beverages, toys, hamburgers, fish boxes, plastic pallets, sewer pipes, oil barrels, packing strings, pipes, hoses, ropes, and waste vinyl. Recycling different types of plastic waste is a complex process and requires a lot of labor and money, making it difficult to obtain economic benefits.

The present invention has been made in view of such a conventional situation, and it is intended to provide a method of regenerating various kinds of plastic wastes appropriately and regenerating them into a truly pure water support fee of a selected kind.

To this end, the present invention provides a method for regenerating plastic waste, in which the collected plastic waste may be pulverized and subjected to specific gravity selection, and the sorted plastic waste may be melted, deodorized and decolorized to obtain a pure resin powder. Mixing white kerosene with waste pulverized powder to melt it and converting it into a low-viscosity liquid.Deodorizing step of spraying concentrated sulfuric acid into a heating tank with a low-viscosity melt of pulverized to burn off odorous substances. Activated clay was added to the melt and stirred to adsorb colored impurities, followed by bleaching. The deodorized melt was stirred and cooled in another tank, followed by centrifugation of the gel-like resin melt to recover liquid white kerosene. Dimensional core separation stage to separate and remove impurities After cooling the gelled resin melt obtained by the first centrifugation to another room temperature at room temperature, injecting normal hexane into the gelled resin melt and stirring to dissolve the residue of white kerosene, a solvent present in the gelled resin melt, with normal hexane. And a second step of centrifugation of the gelled resin melt containing normal hexane in which the white kerosene residue is dissolved, sorting the resin powder and normal hexane, and cooling the normal hexane.

Referring to the present invention in more detail based on the accompanying drawings as follows.

The invention will be described as recycling various plastic waste, but specifically will be described as collecting and recycling plastic waste with the benefit of recycling. For example, the kind of plastic waste handled in the present invention is polyolefin resin such as polyethylene (PE), polypropylene (PP), PAT resin, PA6, PA6.6, PA11, PA12, PA610, etc. among thermoplastic resins. It is an amide resin, and as mentioned above, the styrene resin which becomes high viscosity when heated and melted is excluded.

(1) Collection of plastic waste

Regardless of their type, plastic waste is collected without prior screening. For example, as mentioned above, such plastic waste can be used for various agricultural beverages or containers, toys, hamburgers, fish boxes, plastic pallets, sewer pipes, kegs, packing strings, pipes, hoses, ropes, waste plastics, and the like. And so on. The plastic waste to be collected may be broadly divided into polyolefin-based resins and polyamide-based resins.

(2) crushing

The plastic waste collected without prior screening is cut or crushed to approximately 1 cm x 1 cm using a suitable cutter or grinder.

(3) specific gravity selection

Pulverized products of plastic waste are sorted by type through specific gravity screening using water or brine. For example, the specific gravity of polyolefin resin is about 0.90-0.97, and the specific gravity of polyamide resin is about 1.03. Thereafter, the pulverized products of the plastic waste selected for each type of resin are processed for each type. Accordingly, it should be understood that each of the selected plastic wastes is treated independently, unless specifically noted.

(4) washing with water

As mentioned above, the pulverized plastic waste cut or pulverized to a size of about 1 cm x 1 cm by a suitable cutter or grinder is washed with water to remove foreign matter incorporated therein during the collection process.

(5) Heat melting after mixing white kerosene

The pulverized products of plastic wastes sorted by type are put into a heating tank containing white kerosene having a boiling point of about 300 ° C. and heated to a temperature of about 240 to 260 ° C. while stirring. The pulverized product is melted through a heating stirring process to turn into a dark colored viscous liquid. Particularly heavy impurities that are partly mixed in the mill will settle down.

(6) Deodorization-Deodorization with concentrated sulfuric acid

 A concentrated sulfuric acid is sprayed into the heating tank in which the pulverized product is melted and contained in a state of low viscosity melt. Concentrated sulfuric acid has a specific gravity of about 1.84, so the particles of concentrated sulfuric acid settle in the low-viscosity melt and burn off odorous substances. As a result, impurities in the gel state precipitate with the residual of concentrated sulfuric acid in the lower layer of the melt.

(7) Adsorption decolorization by decolorization-activated clay

Spraying concentrated sulfuric acid to deodorize to remove the odorous substances by spraying activated clay and spraying. Activated clay, which is a kind of adsorbent with increased adsorptive power by chemically treating acidic clay as a raw material, is precipitated by adsorbing various colored impurities in the melt while gradually sinking after being added to the melt. This precipitate is also gelled and precipitates on the precipitate which is produced and precipitated in the deodorization process. These precipitates are discharged and removed in prime.

(8) Primary centrifugation-recovery of white kerosene, deodorization and removal of bleach

After demelting and decolorizing the melt obtained by melting the pulverized plastic waste, the deodorized melt is transferred to another tank and cooled while stirring the melt. As a result, a resin melt in a gel state is obtained at room temperature. Sulfuric acid deodorant or adsorptive decolorant may remain as impurities in the gel-like resin melt. The gel resin melt is transferred to a centrifuge and centrifuged. By this centrifugation, the liquid white kerosene of the upper layer is recovered and the impurities of sulfuric acid deodorant and adsorptive decolorant which are solids of the lower layer are separated and removed.

(9) Separation of Gel Resin Melt

In the first centrifugation process as described above, the white kerosene separated by centrifugation is recovered and the impurities of the sulfuric acid deodorant or the adsorbent decolorizer are separated and removed to obtain a gel-like resin melt. This gel-like resin melt contains fine white kerosene and needs to be removed.

(10) injection / stirring of normal hexane

The gel resin melt obtained by the first centrifugation is transferred to another tank and cooled to room temperature. Normal hexane having a boiling point of 45 to 50 ° C. is injected into the gel resin melt and stirred to dissolve the residue of white kerosene, a solvent present in the gel resin melt.

(11) secondary centrifugation-separated kerosene and normal hexane

The gel-like resin melt contained in the state in which the residue of the white kerosene as a solvent is dissolved by normal hexane is subjected to secondary centrifugation using a centrifuge. The solid powder and the liquid component are separated by this two-dimensional centrifugation. Here, the solid powder is a resin powder and the liquid component is normal hexane in which white kerosene residue is dissolved. Heating the centrifuged liquid component distills off normal hexane with low boiling point. Normal hexane to be distilled may be prepared for cooling and reuse.

(12) resin powder

After the white kerosene residue is separated and removed from the gelled resin melt by normal hexane, a resin powder is obtained. Although the white kerosene residue was separated and removed, a small amount of normal hexane remained in the resin powder. The normal hexane residue was heated to about 50 ° C. to be evaporated, cooled, and recovered to be reused. The resin powder thus obtained is a true pure water support fee to be obtained according to the present invention.

(13) resin powder melt pelletization

The resin powder obtained from these steps can be used for molding a resin product by melting and pelletizing by a conventional method.

As described above, the present invention provides a method for regenerating plastic waste, which is capable of pulverizing the collected general plastic waste, non-selecting and classifying the plastic waste by melting, deodorizing, decolorizing, and refining to obtain pure resin powder.

1 is a process diagram of the present invention.

Claims (1)

In the recycling method of plastic wastes, which is obtained by pulverizing the collected plastic wastes, performing specific gravity selection, melting the sorted plastic wastes, deodorizing and discoloring to obtain pure resin powder. Mixing white kerosene with the pulverized product of plastic waste and melting it to convert it into a low viscosity liquid, Deodorizing step of spraying concentrated sulfuric acid into the heating tank in the low viscosity melt of the pulverization to burn off the smelly substances, Activated clay was added to the low-viscosity melt of the deodorized pulverized product, followed by stirring to adsorb colored impurities to decolorize, One-dimensional core separation step of recovering the liquid white kerosene by centrifuging the gel-like resin melt obtained by stirring and cooling the deodorized decolored melt in another tank, and separating and removing impurities such as sulfuric acid deodorant or adsorptive decolorant. After cooling the gel-like resin melt obtained by the first centrifugation to another room temperature to room temperature, injecting normal hexane into the gel-like resin melt and stirring to dissolve the residue of white kerosene, a solvent present in the gel-like resin melt by normal hexane Wow, A second method of centrifuging a gel-like resin melt containing normal hexane dissolved white kerosene residue to classify the resin powder and normal hexane, and recovering normal hexane, characterized in that the recovery of plastic waste.

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