JP4253354B1 - Waste plastic separation equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a separation apparatus and a separation method capable of separating mixed waste plastic containing at least a polystyrene-based resin with high purity for each plastic composition.
A stirring tank (10) for containing a styrene solubilizer (30) for dissolving a polystyrene resin, and an outlet for dropping and removing a part of the styrene solubilizer (30) at the bottom. (12), heating means (26) for heating the styrene solubilizer (30), and in a horizontal plane arranged in the stirring tank (10) and spaced apart from each other along the depth direction thereof. And at least two or more stirring propellers (20) that rotate. The agitating propeller (20) provides convection parallel to the liquid level so as to reduce the depth convection of the styrene solubilizer (30). The control means (19, 28) controls the output of the heating means (26) and the rotation of the stirring propeller (20) so as not to increase the viscosity of the styrene solubilizer (30).
[Selection] Figure 3

Description

  The present invention relates to an apparatus and a method for separating mixed waste plastic, and more particularly to an apparatus and a method for separating crushed mixed waste plastic containing at least a polystyrene resin.

In order to recycle a plastic product from the collected mixed waste plastic, it is necessary to separate the mixed waste plastic for each plastic composition. As such a separation method, a liquid specific gravity method using a specific gravity difference for each plastic composition is widely used. For example, PE (polyethylene, specific gravity of about 0.92 to 0.94) or PP (polypropylene, specific gravity of about 0.90) having a specific gravity smaller than 1.0 of the specific gravity of water floats on water, while PS ( Polystyrene, specific gravity about 1.03-1.06), PET (polyethylene terephthalate, specific gravity about 1.29-1.40), PVC (polyvinyl chloride resin, specific gravity about 1.16-1.58), etc. in water Settling. Using this property, the former can be distinguished from the latter. Furthermore, if salt water, KCl aqueous solution or K ₂ CO ₃ aqueous solution having a specific gravity higher than that of water is used, PS and PET or PVC having a specific gravity higher than this can be separated.

  For example, Patent Document 1 discloses a method in which after mixing waste plastic is crushed, separation by liquid specific gravity method is repeatedly performed to separate the mixed waste plastic for each plastic composition.

  By the way, in the liquid specific gravity method, the influence of liquid convection is strongly influenced by the shape of the mixed waste plastic piece, so that it is difficult to obtain a stable separation ability. In addition, if bubbles are attached to the mixed waste plastic piece, the apparent specific gravity is reduced, so that it is possible to obtain sufficient separation ability especially for mixed waste plastic that has been crushed into small pieces that are easy to attach bubbles. Can not. Furthermore, although PS has a higher specific gravity than water, a foamed material such as styrene foam obtained by foaming PS still has a small apparent specific gravity, so that sufficient separation ability cannot be obtained.

  Under such circumstances, in recent years, there is a strong demand for more reliable separation and recycling of PS such as polystyrene foam that is frequently used in packaging materials. Therefore, a method for separating PS by a dissolution method is known in which a solvent capable of dissolving only PS is prepared, mixed waste plastic containing PS is crushed and immersed, and only PS is dissolved and separated in the solvent.

For example, Patent Document 2 discloses a method in which only a PS resin is dissolved in xylene from mixed waste plastic, and PS is separated from other plastic compositions such as PVC that are not dissolved in xylene, and recovered. Further, as a solvent capable of dissolving (reducing volume) polystyrene and re-extracting PS like xylene, for example, in Patent Documents 3 to 5, ester compounds and ether compounds are used, and in Patent Document 6, citrus peels are used. Each extracted limonene is disclosed.
JP 2007-15340 A Japanese Patent Laid-Open No. 9-24293 Japanese Patent Laid-Open No. 9-25358 Japanese Patent Laid-Open No. 11-80418 Japanese National Patent Publication No. 01/068759 JP 2001-342286 A

  As described above, Patent Document 2 discloses a method of using xylene to separate and collect only PS from mixed waste plastics by a dissolution method. However, separation of xylene in which PS is dissolved from other plastics is complicated, and handling is also complicated due to the low flash point and high toxicity of xylene. Moreover, the solvent disclosed in Patent Documents 3 to 6 is a volume-reducing solvent that dissolves PS such as styrene foam and gels to reduce the volume, and gels as soon as PS is dissolved. At this time, it is difficult to separate and extract only the solvent in which PS is dissolved because other plastic pieces other than the crushed PS are entrained in the gel. That is, such solvents are not suitable for use in dissolution methods.

  The present invention has been made in view of the situation as described above, and an object of the present invention is to provide a separation apparatus and a separation that can separate mixed waste plastic containing at least a polystyrene resin with high purity for each plastic composition. The provision of a method.

Sorting device according to the invention, at least a sorting apparatus of crushed mixed plastic waste containing polystyrene resin, a stirring tank for containing styrene dissolving agent for dissolving the polystyrene resin, a pre-Symbol styrene solubilizers pressurized Heating means for heating and stirring the styrene solubilizer in the depth direction in a horizontal plane disposed in the stirring tank and spaced apart from each other along the depth direction. At least two agitation propellers rotating at the same time, control means for controlling the output of the heating means and the rotation of the agitation propeller so as not to increase the viscosity of the styrene solubilizer, and at the bottom of the agitation tank And an outlet for taking out the styrene solubilizer below the stirring propeller .

  According to such an apparatus, convection in the depth direction of the styrene solubilizer can be reduced in the stirring tank, and convection parallel to the liquid surface can be obtained. Further, the temperature can be controlled, and only the styrene dissolving agent in which the PS resin is dissolved stays at the bottom of the stirring tank without having a high viscosity like a gel. Thereby, the crushed other plastic piece can stay in the vicinity of the liquid surface by the convection described above without being caught in the styrene dissolving agent in which the PS resin at the bottom of the stirring tank is dissolved. Therefore, since only the styrene dissolving agent which melt | dissolved PS-type resin can be taken out from the taking-out port in the bottom part of a stirring tank, without including the crushed other plastic piece, PS can be isolate | separated with high purity. On the other hand, since the gelled styrene solubilizer hardly adheres to the crushed other plastic pieces, handling such as washing is very easy, and a recycled plastic can be obtained with high purity.

  In the above-described apparatus, the stirring propeller may be provided above the half of the depth of the stirring tank. In particular, the stirring tank is a cylindrical tank having a central axis, and the stirring propeller is preferably arranged along the central axis. According to this, a clean convection parallel to the liquid surface can be obtained in the styrene solubilizer in the stirring tank, and other crushed plastic pieces can be completely retained near the liquid surface. Resin can be separated accurately.

  Further, in the above-described apparatus, the bottom portion of the stirring tank has an inverted conical shape that is convex downward, and the outlet is provided in the vicinity of the lowermost portion of the bottom portion to drop and remove a part of the styrene dissolving agent. It may be a feature. According to this, a clean convection parallel to the liquid surface can be obtained in the styrene solubilizer in the stirring tank, and the styrene solubilizer in which the PS resin is dissolved is entrained with other crushed plastic pieces. And can be dropped and taken out from the outlet at the bottom of the stirring tank. That is, PS resin can be separated with high accuracy.

  In the above-described apparatus, the styrene solubilizer may contain a dicarboxylic acid as a main component. Further, the styrene solubilizer may contain dimethyl succinate, dimethyl adipate and dimethyl glutarate as main components. Such a styrene solubilizer can easily maintain a liquid state without greatly increasing the viscosity even when the PS resin is dissolved, and the styrene solubilizer in the stirring tank can obtain clean convection parallel to the liquid surface. Can do. Thereby, the styrene dissolving agent which melt | dissolved PS-type resin can be dropped and taken out from the taking-out port in the bottom part of a stirring tank, without involving the crushed other plastic piece. That is, PS resin can be separated with high accuracy.

  In the above-described apparatus, the mixed waste plastic may include a polypropylene resin and / or a polyethylene resin and / or a PET resin and / or a polyvinyl chloride resin. Further, the specific gravity of the styrene solubilizer may be slightly larger than the specific gravity of the polystyrene resin at room temperature (20 ° C.) and at least smaller than the specific gravity of the PET resin. According to the styrene solubilizer, the crushed other plastic piece can be completely retained in the vicinity of the liquid surface, so that the PS resin can be accurately separated.

Further, the fractionation method according to the present invention is a fractionation method of crushed mixed waste plastic containing at least a polystyrene resin, and a step of preparing a stirring tank containing a styrene solubilizer for dissolving the polystyrene resin; The step of heating the dissolving agent by a heating means, the step of charging the mixed waste plastic crushed into the stirring tank, and being disposed in the stirring tank and spaced apart from each other along the depth direction thereof An agitation step of agitating the styrene solubilizer in a depth direction with at least two agitating propellers rotating in a horizontal plane, and the heating means so as not to increase the viscosity of the styrene solubilizer an output and a control step of controlling the rotation of the stirring propeller, the stirring propenyloxy in the bottom of the stirring tank It characterized in that it comprises a separation step of taking out the styrene dissolution agent downward, the.

  According to such a method, in the stirring step, the convection in the depth direction of the styrene solubilizer can be reduced in the stirring tank, and a convection parallel to the liquid surface can be obtained. Further, in the control step, the temperature can also be controlled, and only the styrene dissolving agent in which the PS resin is dissolved stays at the bottom of the stirring tank without having a high viscosity like a gel. Thereby, the crushed other plastic piece can stay in the vicinity of the liquid surface by the convection described above without being caught in the styrene dissolving agent in which the PS resin at the bottom of the stirring tank is dissolved. Therefore, only the styrene solubilizer in which the PS resin is dissolved can be taken out without including other plastic pieces crushed from the outlet at the bottom of the stirring tank, so that PS can be separated with high purity. On the other hand, since the gelled styrene solubilizer hardly adheres to the crushed other plastic pieces, handling such as washing is very easy, and a recycled plastic can be obtained with high purity.

  In the above-described separation method, the control step may include a step of stopping the rotation of the stirring propeller prior to the separation step. According to this, these other plastic pieces can be reliably retained in the vicinity of the liquid level without involving other crushed plastic pieces. And only the styrene dissolving agent which melt | dissolved PS type resin can be taken out, without including the other plastic piece crushed from the taking-out port in the bottom part of a stirring tank. Therefore, PS can be separated with high purity.

  In the above-described separation method, the styrene solubilizer may be characterized by containing a dicarboxylic acid as a main component. Further, the styrene solubilizer may contain dimethyl succinate, dimethyl adipate and dimethyl glutarate as main components. Such a styrene solubilizer can easily maintain a liquid state without greatly increasing the viscosity even when the PS resin is dissolved, and the styrene solubilizer in the stirring tank can obtain clean convection parallel to the liquid surface. Can do. Thereby, the styrene dissolving agent which melt | dissolved PS-type resin can be dropped and taken out from the taking-out port in the bottom part of a stirring tank, without involving the crushed other plastic piece. That is, PS resin can be separated with high accuracy.

  In the above-described separation method, the mixed waste plastic may include a polypropylene resin and / or a polyethylene resin and / or a PET resin and / or a polyvinyl chloride resin. Further, the specific gravity of the styrene solubilizer may be slightly larger than the specific gravity of the polystyrene resin at room temperature (20 ° C.) and at least smaller than the specific gravity of the PET resin. According to the styrene solubilizer, the crushed other plastic piece can be completely retained in the vicinity of the liquid surface, so that the PS resin can be accurately separated.

  Furthermore, the above-described separation method may further include a separation step of precipitating and separating the polystyrene resin by a liquid specific gravity method using the styrene solubilizer after the separation step. In a styrene solubilizer that is slightly larger than the specific gravity of the PS resin at room temperature (20 ° C.) and at least smaller than the specific gravity of the PET resin, the specific gravity of the PP resin and the PE resin having a lighter specific gravity than this The heavy PET-based resin and PVC-based resin can be easily separated by the liquid specific gravity method.

  Furthermore, in the fractionation method by the liquid specific gravity method using the styrene solubilizer described above, the fractionation step may include a step of maintaining the temperature of the styrene solubilizer at room temperature. By reducing heat convection, it is possible to more accurately separate PP resin and PE resin having a low specific gravity from PET resin and PVC resin having a high specific gravity.

  In the above-described fractionation method, the method further includes a step of increasing the viscosity by adding a polystyrene resin to a part of the styrene solubilizer taken out in the separation step, and a step of obtaining a polystyrene resin by distilling the polystyrene resin. It is good. By adding a PS resin and increasing the viscosity, high purity PS can be regenerated by distillation.

  A mixed waste plastic separation apparatus and method including at least a polystyrene resin, which is one embodiment of the present invention, will be described in detail with reference to FIGS.

  In particular, in this example, PE resin (polyethylene, specific gravity of about 0.92 to 0.94), PP resin (polypropylene, specific gravity of about 0.90), PS resin (polystyrene, specific gravity of about 1.03 to 1). 0.06), PET-type resin (polyethylene terephthalate, specific gravity about 1.29 to 1.40), PVC-type resin (polyvinyl chloride, specific gravity about 1.16 to 1.58) A method and apparatus for separating these from each plastic composition will be described. In the following, PE resin, PP resin, PS resin, PET resin, and PVC resin are simply referred to as PE, PP, PS, PET, and PVC, respectively.

  As shown in FIG. 1, the collected mixed waste plastic 100 is a manual work or a tool such as a magnet for removing foreign matters other than plastic intended for recovery, such as paper, wood pieces, metal pieces, etc., mixed in the foreign matter removing step. (S101). In the subsequent crushing step, the mixed waste plastic 100 is crushed into a predetermined size (S102). The size of the crushed pieces is preferably about several centimeters square so as to facilitate sorting at least in the liquid specific gravity sorting step (S103) described later.

  Subsequently, PP and PE having a specific gravity smaller than that of water are selected from PS, PET, and PVC having a large specific gravity by a liquid specific gravity method using water (S103). PP and PE that float and are sorted near the liquid surface are further mixed in the liquid specific gravity sorting step (S103) using a known sorting method, for example, a wind sorting method (see Patent Document 1) after drying. Contaminated contaminants can be removed. That is, the obtained PP and PE can be sold as they are, or can be remolded as recycled plastics by a known recycling process (S104). On the other hand, the mixed waste plastic settled in the liquid specific gravity sorting step (S103) is mainly composed of PS, PET, and PVC. Among these, PS is a PS fractionation process including a melting method using a stirring tank 10 described below ( Sorting is performed in S105) (S105).

  As shown in FIG. 2, in the PS separation process (S105), first, the mixed waste plastic settled in the liquid specific gravity sorting step (S103) is collected, and the attached moisture is dried to remove the moisture (S1). The dried mixed waste plastic dissolves only PS while stirring in the stirring tank 10 shown below (S2). At the same time, other crushed resin pieces are floated and separated from the solution containing dissolved PS.

  As shown in FIG. 3, the stirring tank 10 filled with the styrene solubilizer 30 is a substantially cylindrical metal tank having a central axis m. The bottom portion 10a of the stirring tank 10 has an inverted conical shape that protrudes downward, and an outlet 12 for taking out the liquid therein is provided at the tip of the conical bottom portion, that is, near the lowermost portion of the bottom portion 10a. A liquid inlet 13 for introducing the styrene solubilizer 30 into the stirring tank 10 is provided on the upper side of the stirring tank 10.

  Furthermore, a lid 14 is attached to the top of the agitation tank 10 so as to cover it. The lid 14 has a gas vent 15 so that the vaporized gas of the styrene solubilizer 30 inside the stirring vessel 10 can be recovered. From the center part of the cover body 14, the rotating rod 16 hangs toward the center of the conical bottom part 10a. The rotating rod 16 can be rotated by a rotation driving mechanism 18 provided on the lid body 14. The rotation drive mechanism 18 receives a rotation signal from the rotation control unit 19 and rotates at a predetermined rotation direction and a predetermined speed. The tip of the rotating rod 16 reaches a position about half the depth of the agitation tank 10, and a plurality of propellers 20 (three in the figure) are attached at predetermined intervals from the tip. The propeller 20 rotates in a horizontal plane to form a parallel convection parallel to the liquid level on the styrene solubilizer 30 in the stirring tank 10. For example, the propeller 20 is a flat plate and can be adjusted to be inclined slightly from the horizontal plane, for example, by an angle of 30 ° or less.

  The extraction pipe 22 connected to the outlet 12 is provided with a valve 24. When the valve 24 is opened, the styrene solubilizer 30 in the agitation tank 10 can be gravity dropped and extracted. Furthermore, the temperature of the stirring tank 10 can be adjusted so that, for example, the circulating water pipe 26 is spirally wound along the outer surface so that thermal convection does not occur in the styrene solubilizer 30 inside. The temperature adjustment of the styrene solubilizer 30 is controlled by the temperature control unit 28.

  A styrene solubilizer 30 that is soluble in a PS resin preheated to a predetermined temperature is introduced into the stirring tank 10 through the liquid inlet 13. The styrene solubilizer 30 is a solubilizer mainly composed of dicarboxylic acid, for example, dimethyl succinate, dimethyl adipate and dimethyl glutarate. This is produced from a mixed acid produced in an adipic acid production plant and is preferably about 20% dimethyl succinate, 20% dimethyl adipate, and 60% dimethyl glutarate. At this time, the specific gravity of the styrene solubilizer 30 was about 1.09 to about 1.10, and the analytical value was 1.092. That is, it is almost the same as or slightly larger than that of styrene, and at least smaller than the specific gravity of PET. It should be noted that other known solvents can be used as long as they have the same specific gravity and are soluble in PS resins. These may be solvents used as a volume reducing agent for styrene foam, and are preferably solvents whose viscosity does not rapidly increase with the dissolution of styrene.

  The temperature of the styrene solubilizer 30 is kept constant by adjusting the temperature of the water flowing through the circulating water pipe 26 of the stirring tank 10 by the temperature controller 28. As described later, the temperature of the styrene solubilizer 30 is preferably a high temperature from the viewpoint of preventing so-called gelation, in which the viscosity of the dissolved PS is increased. On the other hand, the amount of vaporization of the styrene solubilizer 30 increases, and temperature convection easily occurs in a direction perpendicular to the liquid level of the styrene solubilizer 30 in the stirring tank 10. That is, the parallel convection by the propeller 20 is disturbed. Therefore, the temperature of the styrene solubilizer 30 is not less than room temperature and not more than 70 ° C., preferably not more than 60 ° C.

  When a switch (not shown) of the agitation tank 10 is turned on, the rotation control unit 19 drives the rotation drive mechanism 18 to rotate the rotating rod 16 at a predetermined rotation direction and a predetermined speed. As shown in FIG. 3, the styrene solubilizer 30 in the stirring tank 10 reduces the convection in the depth direction by a plurality of propellers 20 rotating in a horizontal plane, and forms a parallel flow F along the liquid surface. To do. At this time, the flow f in the vicinity of the bottom 10a of the stirring vessel 10 that is deeper than the propeller 20 at the deepest position is gentler than the flow F.

In turn, refer also to Fig. 3 in FIG. 2, the mixed waste plastic moisture dried to a stirring tank 10, you put the inlet (not shown) provided in the lid 14. At this time, when the amount of mixed waste plastic is large, the viscosity of the styrene solubilizer 30 in which PS is dissolved in the stirring tank 10 is increased, and a resin other than PS is entrained therein. Therefore, it is preferable that the input amount of the mixed waste plastic is smaller than the weight of the styrene solubilizer 30. On the other hand, in the gelation step (S8) in which the styrene solubilizer 30 in which PS is dissolved is taken out from the agitation tank 10 described later and gelled, the amount of PS to be charged increases. Therefore, the input amount of the mixed waste plastic is appropriately adjusted while taking care that the viscosity of the PS does not rapidly increase in the stirring tank 10 to be gelled.

The rotation control unit 19 controls the rotation speed of the propeller 20 so as to reduce the convection in the depth direction of the styrene solubilizer 30 and keep maintaining the convection parallel to the liquid surface. Further, the temperature control unit 28 controls the temperature of the styrene solubilizer 30. Thus, only the PS of the mixed waste plastic dissolves in the styrene dissolution agent 30 (S 2). By parallel convection, small pieces such as PET and PVC that remain without being dissolved do not mix with the styrene dissolving agent 30 in which PS is dissolved. Further, as PS dissolves in the styrene solubilizer 30, the density of some of them changes and the viscosity tends to increase, but this is eliminated by the formation of gentle parallel convection by the rotation control unit 19 and the temperature control unit 28. It is.

  Eventually, the styrene solubilizer 30 in which PS is dissolved stays at the bottom of the stirring tank 10 without having a high viscosity like a gel, while other small pieces such as PET and PVC stay near the liquid surface. In addition, the small piece of PET and PVC having a specific gravity larger than that of the styrene solubilizer 30 stays in the vicinity of the liquid surface due to the fact that the small piece is lifted by resistance due to the parallel convection of the styrene solubilizer 30. To do. In order to ensure that small pieces such as PET and PVC stay in the vicinity of the liquid surface, crushing such that the size of the small pieces is adjusted again after the first crushing step (S102) and before the PS separation process (S105). A process may be performed.

In the styrene solubilizer 30 at the bottom of the stirring tank 10, the switch of the stirring tank 10 (not shown) is turned off before the concentration of dissolved PS increases and the viscosity increases. The rotation control unit 19 stops the rotation drive mechanism 18 and stops the rotation rod 16. Immediately after the propeller 20 is stopped or left for a while, the valve 24 is opened, and a part of the styrene dissolving agent 30 is dropped from the outlet 12 by gravity (S3 ) . At this time, since the bottom 10a of the stirring tank 10 is convex downward, only the styrene dissolving agent 30 in the vicinity of the bottom 10a can be taken out without forming a vertical convection in the styrene dissolving agent 30. The extracted styrene solubilizer 30 is carried to a storage tank 32. The vaporized styrene solubilizer 30 is led from the gas vent 15 of the lid 14 to a heat exchanger (not shown), is again made into a liquid, recovered, and reused.

  Subsequently, the styrene solubilizer 30 is replenished in the agitation tank 10 (S4), and the above-described PS resin is dissolved and the styrene solubilizer 30 is taken out again (S5). A styrene solubilizer 30 in which PS is inevitably entangled with small pieces such as PET and PVC that remain without being dissolved. This is for cleaning. A part of the styrene solubilizer 30 taken out from the outlet 12 by opening the valve 24 is also carried to the storage tank 32 (S3 ').

  Next, the valve 24 is opened again, and the styrene solubilizer 30 remaining in the stirring vessel 10 is removed by gravity drop from the outlet 12 and transferred to a centrifuge (not shown). At this time, if the styrene solubilizer 30 has a high viscosity, the pieces such as PET and PVC and the styrene solubilizer 30 cannot be centrifuged. However, in this embodiment, since the styrene solubilizer 30 can maintain a low-viscosity liquid state, the styrene solubilizer 30 and small pieces (residual substances) such as PET and PVC are separated by centrifugation (S6). The centrifugation step (S6) may be a step of filtering residual substances using, for example, a mesh. The styrene solubilizer 30 thus recovered is also transported to the storage tank 32 (see FIG. 3) (S3 ″).

  On the other hand, the fractionated residual material is further fractionated by a liquid specific gravity method using a styrene solubilizer 30 at about room temperature (about 15 to 20 ° C.) (S7). The residual material is put into the styrene solubilizer 30 and left for a while after stirring. The light specific gravity 41 that has surfaced is the remaining PP or PE. On the other hand, the sedimented heavy specific gravity 42 is PET or PVC. These are appropriately recycled and the like.

  In the gelation step, the styrene solubilizer 30 in the storage tank 32 is charged with PS resin while being heated to increase the viscosity, that is, gelled (S8). The heating temperature of the styrene solubilizer 30 is lower than the temperature of the styrene solubilizer 30 at least in the stirring and dissolving step (S3) and the re-stirring and dissolving step (S5). Here, when the PS resin is charged at a mass ratio of the styrene-based solubilizer 30 and the PS-based resin having substantially the same specific gravity to about 1: 2, the styrene solubilizer 30 gels. When this gel is taken out and supplied to a known distillation tower to distill the styrene solubilizer 30, regenerated PS can be obtained (S9). Details are well known and will not be described in detail.

  As described above, according to the present embodiment, high-purity PS can be regenerated because no other plastic piece is mixed into the styrene-based solubilizer in which PS is dissolved. On the other hand, since the gel-like solubilizer does not adhere to the plastic pieces other than the PS-based resin, handling such as washing is easy, and a high-purity recycled plastic can also be obtained.

  In addition, although the typical Example by this invention and the modification based on this were demonstrated, this invention is not necessarily limited to these, Those skilled in the art do not deviate from the attached claim. Various alternative embodiments and modifications may be found.

It is process drawing of the classification method of the mixing waste plastic by this invention. It is process drawing of the classification method of the mixing waste plastic by this invention. It is sectional drawing of the separation apparatus of the mixed waste plastic by this invention.

Explanation of symbols

DESCRIPTION OF SYMBOLS 10 Stirring tank 12 Outlet 13 Liquid inlet 14 Cover 15 Degassing port 16 Rotating rod 19 Rotation control part 20 Propeller 22 Extraction pipe 26 Circulating water pipe 28 Temperature control part 30 Styrene dissolving agent 32 Storage tank S105 PS separation process

Claims (7)

A device for separating crushed mixed waste plastic containing at least a polystyrene-based resin and a resin having a higher specific gravity than this,
A stirring tank filled with a polystyrene resin and a soluble styrene solubilizer;
Heating means for heating the styrene solubilizer;
Stirring the styrene solubilizer to form two layers of a first layer of parallel flow along the liquid level and a more gradual second layer of the lower flow, the depth of the stirring tank At least two or more agitating propellers rotating in a horizontal plane provided above the half and spaced apart from each other along its depth direction;
And a take-out port for taking out the styrene-dissolving agent in the second layer at the bottom of the agitation tank.   The apparatus for separating mixed plastic waste according to claim 1, wherein the stirring tank is a cylindrical tank having a central axis, and the stirring propeller is disposed along the central axis.   The bottom portion of the stirring tank has an inverted conical shape convex downward, and the outlet is provided in the vicinity of the lowermost portion of the bottom portion to drop a part of the styrene solubilizer and take it out. 2. The apparatus for separating mixed waste plastics according to 2.   4. The mixed waste plastic separation apparatus according to claim 1, wherein the styrene solubilizer contains dicarboxylic acid as a main component.   5. The apparatus for separating mixed waste plastics according to claim 4, wherein the styrene solubilizer is mainly composed of dimethyl succinate, dimethyl adipate and dimethyl glutarate.   The mixed waste plastic includes a polypropylene resin and / or a polyethylene resin and / or a PET resin and / or a polyvinyl chloride resin, according to claim 1. Waste plastic separation equipment. The mixed waste plastic separation device according to claim 6, wherein the specific gravity of the styrene solubilizer is larger than the specific gravity of the polystyrene resin at room temperature and smaller than the specific gravity of the PET resin .