JPH10235644A - Method for vertical wet separation by specific gravity of plastic refuse - Google Patents

Abstract

PROBLEM TO BE SOLVED: To enhance amt. of processing while separation efficiency is kept by removing intermittently settled plastics from the bottom when chlorine-contg. plastics being harmful to burning or injection to a blast furnace are separated by specific gravity. SOLUTION: Lightweight side of plastics separated in a specific gravity separation tank 8 is transferred to a vibration screen 17 through a top pipe 15 and it is separated from a specific gravity liq. and it is transferred to a container 19 for lightweight plastics. On the other hand, heavy weight side is transferred to a vibrational screen 18 through a bottom pipe 16 and a valve 25 and after it is separated from the specific gravity liq., it is transferred to a container 20 for heavy weight plastics. In this instance, the valve 25 is ordinarily made under closed condition and the heavy weigh plastics are stored in the bottom part of the separation tank. Thereafter, after some amt. of the heavy weight plastics are stored in the bottom part of the separation tank, valve 25 is opened for a definite time to transfer the heavy weight plastics to the container 20 for the heavy weight plastics through a pipeline 16 and the vibrational screen 18.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to the separation of a plurality of types of waste plastics, and more particularly to the separation of plastics in general and industrial wastes for the purpose of reuse or incineration (solidification), blast furnace injection, and oiling. The present invention relates to separation of chlorine-containing plastics (PVC, PVDC, etc.) by specific gravity difference.

[0002]

2. Description of the Related Art Plastic wastes in general and industrial wastes, when treated, emit toxic gas derived from chlorine-containing plastics if incinerated.
In the blast furnace injection, the permissible content of chlorine-containing plastic must be 1% or less, so that it cannot be used for blast furnace injection recycling, and the landfill requires a large land area due to its large volume ratio.

As a separation method, a sink float, a liquid cyclone, a vertical wet separator, and a centrifugal separator are known. However, the sink float, the liquid cyclone, and the vertical wet separator have poor separation efficiency with respect to film-based plastic. Although the centrifugal separator has a high separation efficiency, it has a drawback that the device is expensive and the throughput is small.

[0004] In terms of the balance between the throughput and the separation efficiency, a vertical wet separation apparatus is effective among the above four types. Here, the vertical type wet separation device is configured to have a conical cone portion at the upper and lower portions of a cylindrical separation tank main body, and an appropriate size from the center of the cylindrical separation tank main body. The waste plastic to be separated is supplied together with a specific gravity liquid (usually water), settled by the specific gravity in the main body, and the plastic that has risen is discharged together with the specific gravity liquid from the lower or upper part, and the high specific gravity component and the low specific gravity component are removed. What separates.

[0005] Also in this vertical wet separation apparatus, the separation efficiency is about 95% and the throughput is about 1 t / h. Further, when processing a film-based plastic that accounts for about 50% by weight and 80% or more by volume, there is a problem that the lower pipe portion is clogged by the film, and the processing amount is reduced.

[0006]

DISCLOSURE OF THE INVENTION The present invention is directed to a vertical wet-type separation apparatus in which chlorine-based plastic is removed from waste plastics by improving the processing amount, the generation of harmful gases in incineration is reduced, and the blast furnace is blown. The method is intended to provide a separation method capable of treating waste plastic for recycling by reducing the content of chlorine-based plastic to 1% or less.

Since the throughput of the vertical wet separation device is limited by clogging of the lower piping, it is effective to increase the flow rate of the lower piping. However, the vertical wet separation device reduces the flow rate in the separation tank body. If it is raised, the separation efficiency will decrease. In order to increase the lower flow rate while maintaining the separation efficiency, there is a problem that the size of the apparatus itself becomes larger.

[0008]

According to the vertical wet specific gravity separation method for plastic waste of the present invention, a vertical wet specific gravity separator is used to separate chlorine-containing plastics harmful to combustion or blowing into a blast furnace from waste plastics. Upon separation, the sedimented plastic is intermittently withdrawn from the lower part.

Specifically, a valve is provided in the lower piping section,
When a certain amount of plastic has settled,
Open the valve to drain the sedimented plastic at a high flow rate.

In this way, by intermittently removing the settled plastic at a high flow rate, it is not necessary to increase the size of the apparatus, and the throughput can be improved without lowering the separation efficiency.

[0011]

FIG. 1 shows an example of an embodiment of the present invention.
Shown in The plastic waste put into the hopper 1a is put into the crusher 2 by the conveyor 1. The plastic crushed to an appropriate size (5 to 50 mm) by the crusher 2 is put into the mixing tank 5 via the blower 3 and the cyclone 4 and mixed and diffused into the specific gravity liquid by the stirrer 6.

The specific gravity liquid mixed with the plastic is sent to the supply port 9 of the main body specific gravity separation tank 8 by the pump 7,
In the specific gravity separation tank, the liquid is separated into an upper part and a lower part according to a specific gravity difference from a specific gravity liquid.

On the other hand, metals, stones and the like mixed in the plastic waste are conveyed to the vibrating sieve 11 by the screw conveyor 10 below the mixing tank 5, separated from the specific gravity liquid and conveyed to the soil and metal recovery container 12. Is done. The separated specific gravity liquid is pipe 1
3 and is sent to the specific gravity liquid recovery container 14.

The plastic separated in the specific gravity separation tank 8 is conveyed on the light side to the vibrating sieve 17 via the upper pipe 15 and separated from the specific gravity liquid so that the lightweight plastic container 1 is separated.
9.

On the other hand, the weight side is conveyed to the vibrating sieve 18 via the lower pipe 16 and the valve 25, separated from the specific gravity liquid, and then conveyed to the heavy plastic container 20. At this time,
The valve 25 is normally closed, and an appropriate amount of heavy plastic is stored in the lower part of the separation tank. Thereafter, after the heavy plastic has been somewhat accumulated in the lower portion of the separation tank, the valve 25 is opened for a certain period of time, and the heavy plastic is conveyed to the heavy plastic container 20 through the pipe 16 and the vibrating sieve 18.

By opening the valve for a certain period of time, the flow rate at the time of discharge can be increased, so that the processing amount can be increased without clogging of the plastic in the pipe 16. By setting the opening time of the valve within the residence time of the specific gravity liquid from the supply port 9 to the lower cone portion 8a, the separation efficiency did not change.

On the other hand, the separated specific gravity liquid is supplied to a pipe 21.22.
To the specific gravity liquid container 14. The specific gravity liquid in the specific gravity liquid container is returned to the mixing tank 5 by the pump 23 and the pipe 24.

In the method of separating plastics according to the present invention, polyethylene and polypropylene can be recovered from plastic waste as floating substances, and chlorine-based plastic, polystyrene and polyethylene terephthalate can be recovered as sediment. Moreover, specific gravity 1.1 is used as a specific gravity liquid.
Polystyrene can be recovered as a float by using a liquid having a specific gravity of a certain level. Also, the processing amount is about 2 t /
h can be achieved.

[0019]

According to the present invention, the processing amount, which was 0.5 t / h without a valve, has been improved to about 2 t / h. Further, a device such as a scraping mechanism for preventing blockage of the lower piping is not required.

[Brief description of the drawings]

FIG. 1 is an explanatory view showing an example of an embodiment of an apparatus for carrying out the method of the present invention.

[Explanation of symbols]

5: mixing tank, 8: specific gravity separation tank, 8a: lower cone part, 9
... supply port of specific gravity liquid mixed with plastic, 15 ... upper pipe, 16 ... lower pipe, 25 ... valve.

──────────────────────────────────────────────────の Continued on the front page (51) Int.Cl. ⁶ Identification symbol FI B09B 5/00 ZAB C08J 11/04 ZAB // C08J 11/04 ZAB B09B 5/00 ZABQ B29K 105: 26

Claims (1)

[Claims] When a chlorine-containing plastic harmful to combustion or blowing into a blast furnace is separated from waste plastics by means of a vertical wet specific gravity separator, sedimented plastic from the lower part is intermittently extracted. Vertical wet specific gravity separation method for waste plastic.