JP2935383B2 - Specific gravity separation method and apparatus for crushed plastic - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method and an apparatus for separating mixed crushed plastics, and more particularly to a method and an apparatus for separating mixed plastics such as polypropylene, polystyrene and vinyl chloride.

[0002]

2. Description of the Related Art Conventionally, for separating a mixed plastic, a method of separating a crushed plastic by a wind force based on a difference between its own weight and an air resistance, and a method of separating a crushed product in water or various specific gravity liquids by utilizing a specific gravity difference. And a flotation method in which the separation is performed based on the coarse water and the way in which bubbles are formed by surface modification.

[0003] Among the above methods, the specific gravity fractionation method is less susceptible to the influence of the shape and size, and is therefore advantageous for the separation of plastics which are hard to be pulverized to a uniform particle diameter.

[0004]

However, an aqueous solution in which an inorganic salt is dissolved in water is often used as a specific gravity liquid for specific gravity separation. However, an aqueous solution of an inorganic salt forms a specific gravity liquid having a specific gravity of 1.0 or more. Even if this is easy, a specific gravity liquid having a specific gravity of 1.0 or less cannot be produced. For this reason, it was difficult to accurately separate a crushed plastic having a specific gravity of 1.0 or less from a mixture of two or more crushed plastics having different specific gravities, including a crushed plastic having a specific gravity of 1.0 or less.

As a solution to this problem, it is conceivable to use alcohols or oils in a specific gravity liquid having a specific gravity of 1.0 or less. However, it is also possible to use such a liquid in combination with another specific gravity liquid such as an aqueous solution in which an inorganic salt is dissolved. In such a case, there is a problem of a change in the set specific gravity and contamination due to mixing of specific gravity liquids having different characteristics. The present invention
In view of such circumstances, it is an object of the present invention to solve the drawbacks of the conventional method and to provide a method and an apparatus for separating crushed plastics for accurately separating crushed plastics mixed with polypropylene, polystyrene, vinyl chloride, etc. by specific gravity. With the goal.

[0006]

According to the present invention, in order to achieve the above object, a mixture of two or more types of crushed plastics having different specific gravities, including crushed plastics having a specific gravity of 1.0 or less, is classified by type. In the method for fractionating the specific gravity of crushed plastic, fine bubbles of high-pressure air are quantitatively and uniformly mixed with water, and a specific gravity liquid having a specific gravity of 1.0 or less is prepared by the mixing operation. A mixture of two or more types of crushed plastics having different specific gravities, including a crushed plastic having a specific gravity of 1.0 or less, is supplied to a specific gravity liquid having a specific gravity of 0.0 or less, and a crushed plastic having a specific gravity smaller than the set specific gravity is added. The crushed plastic having a specific gravity higher than the set specific gravity is floated on the specific gravity liquid, and sedimented into the specific gravity liquid to be separated.

[0007] In order to achieve the above object, the present invention provides a crushed plastic specific gravity separation apparatus for separating a mixture of two or more crushed plastics having different specific gravities, each containing a crushed plastic having a specific gravity of 1.0 or less. A water tank for storing water and separating the mixture of crushed plastics into those that float and those that settle by a difference in specific gravity; supply means for supplying the mixture of crushed plastics to the water tank; and high pressure water in the water tank. A diffusing means for quantitatively blowing fine air bubbles.

[0008]

As described below, the present invention separates a crushed plastic having a specific gravity of 1.0 or less from a mixture of two or more crushed plastics having different specific gravities including a crushed plastic having a specific gravity of 1.0 or less. First, high-pressure air is supplied to a diffuser provided in a water tank, and fine bubbles formed by the diffuser are quantitatively blown into water stored in the water tank to be uniformly mixed. I do.

By the above operation, the specific gravity of the water stored in the water tank can be apparently reduced to 1.0 or less, and by changing the amount of air mixed with the water stored in the water tank, The apparent specific gravity of water can be adjusted. When a mixture of two or more types of crushed plastics having different specific gravities, including a crushed plastic having a specific gravity of 1.0 or less, is added to the specific gravity liquid having an apparent specific gravity of 1.0 or less prepared by the above operation, In the mixture, the crushed plastic having a specific gravity smaller than the set specific gravity floats on the specific gravity liquid, and the crushed plastic having a specific gravity larger than the set specific gravity is settled in the specific gravity liquid.

[0010] Thus, a crushed plastic having a specific gravity of 1.0 or less can be accurately separated from a mixture of two or more types of crushed plastics having different specific gravities, including a crushed plastic having a specific gravity of 1.0 or less. .

[0011]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the method and apparatus for separating specific gravity of granules according to the present invention will be described below in detail with reference to the accompanying drawings. As shown in FIG. 1, a light specific gravity liquid tank 10 and a heavy specific gravity liquid tank 12 are provided in parallel, and the upper part of the light specific gravity liquid tank 10 contains particles having a specific gravity of 1.0 or less. A mixed particle supply tank 14 for storing a mixture of a plurality of particles (crushed plastic) having different specific gravities is provided.

Further, a screw conveyor 16 for transferring and charging the mixture from the mixed granular material supply tank 14 to the light specific gravity liquid tank 10 is provided below the mixed granular material supply tank 14. An outlet 18 is located above the light specific gravity liquid tank 10. The light specific gravity liquid tank 1
At the bottom in 0, high pressure air is formed into fine bubbles,
A diffuser plate 20 for uniformly mixing the fine bubbles with a specific gravity liquid is provided, and a high-pressure air pipe 22 extends from the diffuser plate 20 through the bottom plate of the light specific gravity liquid tank 10 to a compressor (not shown). It is connected.

The light specific gravity liquid tank 10 and the heavy specific gravity liquid tank 12 have conveyors 24 and 26 for collecting the particles floating in the specific gravity liquid, and a conveyor 28 for collecting the settled particles and transporting them to the next step. , 30 are provided. The operation of the apparatus having the above-described structure for separating the crushed plastic particles of polypropylene, polystyrene, and vinyl chloride from the specific gravity will be described.

First, as a preparation, water is stored in the light specific gravity liquid tank 10, a compressor (not shown) is operated, and high-pressure air 32 is quantitatively sent to the diffuser plate 20 through the high-pressure air pipe 22, and is dispersed. Fine bubbles formed by a gas plate are blown into water and mixed uniformly to prepare a light specific gravity liquid 34 in which the apparent specific gravity of water is maintained at about 0.95. On the other hand, in the heavy specific gravity liquid tank 12, a specific gravity liquid 36 in which magnesium sulfate is dissolved in water and the specific gravity is adjusted to about 1.1 is stored.

Further, a plastic in which polypropylene, polystyrene and vinyl chloride are mixed is crushed into granules having a size of several mm by a method such as low-temperature crushing and the like, and is put in the mixed granule supply tank 14. When the above preparation is completed, the mixed granular material supply tank 14
A mixture of crushed plastic of polypropylene having a specific gravity of about 0.9, polystyrene having a specific gravity of about 1.0, and vinyl chloride having a specific gravity of about 1.3 is charged into the light specific gravity liquid tank 10 by the screw conveyor 16.

Since the specific gravity of the light specific gravity liquid 34 is set to about 0.95, the specific gravity of the light mixture is 0.15 in the charged mixture.
The polypropylene particles of about 9 float on the light specific gravity liquid 34 and are collected by the collection conveyor 24. On the other hand, specific gravity 1.
A mixture of polystyrene particles having a specific gravity of about 0 and vinyl chloride particles having a specific gravity of about 1.3 settles at the bottom of the light specific gravity liquid tank 10, is collected by the collection conveyor 28, and is conveyed to the heavy liquid tank 12.

Since the specific gravity of the specific gravity liquid 36 is set to about 1.1, the specific gravity of the mixture of polystyrene and vinyl chloride particles charged into the specific gravity liquid tank 12 is about 1.0. The polystyrene particles float on the specific gravity liquid 36 and are collected by the collection conveyor 26. On the other hand, specific gravity 1.3
The vinyl chloride particles settle to the bottom of the specific gravity liquid tank 12 and are collected by the collection conveyor 30.

In this way, a mixture of granules of crushed plastics of polypropylene, polystyrene, and vinyl chloride having different specific gravities can be accurately separated by specific gravity. Further, even if the light specific gravity liquid 34 in the light specific gravity liquid tank 10 adheres to the plastic particles and is entrained in the heavy specific gravity liquid tank 12 which is an aqueous solution of magnesium sulfate and mixed with the heavy specific gravity liquid 36, Since it is water, it does not affect the specific gravity of the heavy liquid 36 or contaminate the heavy liquid 36.

In the above embodiment, water is used as the light specific gravity liquid, but a small amount of a surfactant or the like may be added to water to increase the hydrophilicity of the plastic. In the above embodiment, the case where the three types of crushed plastics are separated by specific gravity has been described. However, the present invention is not limited to this.
And four or more types of crushed plastic can be separated.

[0020]

As described above, according to the crushed plastic specific gravity separation method and apparatus according to the present invention, high-pressure air is sent to the diffuser plate provided at the bottom of the water tank, and fine bubbles are generated by the diffuser plate. Is formed, and the microbubbles are uniformly mixed with the water stored in the water tank, so that the apparent specific gravity is 1.
A specific gravity liquid of 0 or less can be prepared.

[0021] Thus, a crushed plastic having a specific gravity of 1.0 or less can be accurately separated from a mixture of two or more types of crushed plastics having different specific gravities, including a crushed plastic having a specific gravity of 1.0 or less. Further, since the specific gravity liquid adjusted by the above operation is water, when used in combination with another specific gravity liquid such as an aqueous solution in which an inorganic salt is dissolved, a change in specific gravity or contamination due to mixing of specific gravity liquids is a problem. No.

[Brief description of the drawings]

FIG. 1 is an explanatory view of a method and an apparatus for separating specific gravity of crushed plastic according to the present invention.

[Explanation of symbols]

 Reference Signs List 10 specific gravity liquid tank 20 diffuser plate 22 high-pressure air pipe 32 high-pressure air

Continuation of front page (56) References JP-A-50-37874 (JP, A) JP-A-50-108102 (JP, A) JP-A-50-122577 (JP, A) JP-A-51-34801 (JP) , A) (58) Field surveyed (Int. Cl. ⁶ , DB name) B03B 5/00-5/74 B03D 1/00-1/26

Claims (2)

(57) [Claims] 1. A method for separating a mixture of two or more types of crushed plastics having different specific gravities, each containing a crushed plastic having a specific gravity of 1.0 or less, by a method for separating crushed plastics by specific gravity. The mixture is quantitatively and uniformly mixed with water to prepare a specific gravity liquid having a specific gravity of 1.0 or less by the mixing operation. The specific gravity liquid having a specific gravity of 1.0 or less is added to the specific gravity liquid having a specific gravity of 1.0 or less.
A mixture of two or more types of crushed plastics having different specific gravities, including a crushed plastic of 0 or less, is charged, and crushed plastics having a specific gravity smaller than the set specific gravity are caused to float on the specific gravity liquid. Is settled in the specific gravity solution and separated to separate the specific gravity of the crushed plastic. 2. A crushed plastic specific gravity separation device for separating a mixture of two or more crushed plastics having different specific gravities, each containing a crushed plastic having a specific gravity of 1.0 or less, storing water therein. A water tank that separates the mixture of crushed plastics into those that float and those that settle due to the difference; supply means for supplying the mixture of crushed plastics to the water tank; and fine bubbles of high-pressure air are quantitatively blown into the water in the water tank. A specific gravity separation device for crushed plastic, comprising: an air diffuser.