KR101427548B1 - Method and apparatus for separating plastics - Google Patents

Abstract

A first specific gravity selecting step of discriminating a plastic which is lighter than the first specific gravity threshold value (P1) from a mixed crushing plastic by a specific gravity selecting method; and a second gravity selecting step of selecting a specific gravity value (P1 Detecting X-rays from the X-ray source, irradiating the X-ray source with the lightweight plastic, detecting transmitted X-rays from the separated lightweight plastic by a transmission X-ray detector, And a cancellation-containing plastic removing process for removing the cancellation-containing plastic from the separated light plastic by the presence or absence of cancellation based on a signal from the data processing section that discriminates the presence of cancellation in the discriminated light plastic.

Description

[0001] METHOD AND APPARATUS FOR SEPARATING PLASTICS [0002]

The present invention relates to a method and apparatus for sorting plastics that can be reused in household appliances from mixed crushed plastics obtained from waste household appliances.

Regarding the conventional recycling plastic sorting method, there is a technique of sorting plastics for each kind by a wet sorting function (specific gravity sorting function) using specific gravity difference (for example, Patent Document 1). In addition, there is a technique of sorting the electrostatic system for each type by charging the plastic having the charging property by friction or the like, and using the charging property of the various plastics different from each other (for example, Patent Document 2). Flame retardant resins containing flame retardants have been used in some of the plastics used in home appliances. The content of the flame retardant is usually 1 to 30% by weight, and a flame retardant mainly used is a cancellous flame retardant.

On the other hand, in order to secure and manage the performance of the recycled plastic, a technology for sorting the flame retardant-containing resin and the non-containing resin has become important techniques. In addition, while advancing the effective use of recycled plastics in household electrical appliances, we are working to improve the use of canned flame retardants in the regulation of hazardous substances represented by the European RoHS Directive (Directive on the Restriction of the Use of Certain Hazardous Substances Contained in Electrical and Electronic Equipment) In order to comply with the content regulation, it is also necessary to prevent the incompatibility of the reclaimed plastic with the flame retardant in the recycling process in the plastic recycling process.

A separation technique for separating the flame retardant containing flame retardant into a plastic containing no flame retardant has become important so that the remaining cancellous flame retardant is not incorporated into the recycled resin when the ovonic plastic containing such flame retardant is recycled.

2. Description of the Related Art Conventionally, as a plastic separator, a separation object is conveyed by a conveying means such as a conveyor, a separation object is irradiated with radiation, a transmittance of the radiation passing through the material is measured, (For example, refer to Patent Document 3).

Japanese Patent Laid-Open No. 2003-112156 Japanese Patent Application Laid-Open No. 2007-111600 Japanese Patent Laid-Open No. 1993-131176

In the conventional method for producing recycled plastics, particularly, in the method of selecting by specific gravity, plastics containing a large amount of cancellation-based flame retardants that are heavier than plastics are removed, but plastics containing a small amount of plastics are not removed, There is a problem of exceeding the content. Further, by lowering the threshold value for specific gravity selection, the removal rate of the plastic containing the canceling flame retardant agent is improved, but the recovery rate of the plastic to be recycled is lowered.

In addition, in the above-described separating apparatus, the plastic containing the specific element is determined as the transmittance of the radiation passing through the object to be separated. However, the transmittance of the radiation is not limited to the weight or the content of the element contained in the object to be separated, . Therefore, when the size or thickness of the object to be separated is not constant, such as a crushed plastic piece, there is a problem that the determination of the plastic piece containing the specific element is wrong.

SUMMARY OF THE INVENTION The present invention has been made in order to solve the above-mentioned problems, and it is an object of the present invention to provide a plastic sorting method relating to a method for producing recycled plastic which removes plastic containing a flame- Purpose.

It is another object of the present invention to provide a plastic sorting apparatus capable of sorting plastic pieces having various thicknesses with high accuracy in the sorting method.

The method for producing a recycled plastic according to the present invention comprises a first specific gravity selecting step of sorting plastics that are lighter than the first specific gravity value (P1) by the gravity selection method from the mixed crushed plastic, A step of determining a specific gravity threshold value (P1) in a specific gravity sorting step, a step of irradiating X-rays from an X-ray source onto the separated lightweight plastic, and a transmission X-ray detector Based on a signal from a data processing section for analyzing the data of the detected transmitted X-rays and determining the presence or absence of cancellation in the discriminated light plastic, And a cancellation-containing plastic removing process for removing the can.

In the method for producing a recycled plastic according to the present invention, the plastic containing a large amount of the canceling flame retardant is excluded by the non-gravity selection, and the plastic containing the canceling flame retardant is selectively excluded from the plastic containing a small amount of the canceling- It is possible to improve the recovery rate of the plastic to be recycled and to improve the discrimination degree and the processing speed of the canned / non-contained can.

1 is a flowchart of a method for manufacturing a recycled plastic according to Embodiment 1 of the present invention,
2 is a view showing the configuration of a floatation separator for carrying out the specific gravity separation process according to Embodiments 1 and 2 of the present invention,
3 is a diagram showing a configuration of a device for detecting the cancellation and performing the process of removing the cancellation-containing plastic according to the first and second embodiments of the present invention,
4 is a flowchart of a method for producing a recycled plastic according to Embodiment 2 of the present invention,
5 is a diagram showing a configuration of an electrostatic separation apparatus for carrying out the electrostatic separation process according to Embodiment 2 of the present invention,
6 is a view showing an example of the specific gravity distribution of PP, PS and ABS of the mixed crushing plastic,
7 is a view for explaining the effectiveness of the manufacturing method according to the present invention,
8 is a view for explaining the effectiveness of the manufacturing method according to the present invention,
9 is a schematic view showing a plastic sorting apparatus according to Embodiment 3 of the present invention,
Fig. 10 is a perspective view showing a thickness discriminating portion in the plastic sorting apparatus shown in Fig. 1,
Fig. 11 is a top view of the thickness discriminating portion shown in Fig. 9,
12 is a cross-sectional view taken along line AA in Fig. 11,
13 is a cross-sectional view taken along the line BB in Fig. 11,
14 is a graph showing the relationship between the X-ray transmittance and the thickness of the plastic piece according to Embodiment 3 of the present invention,
15 is a perspective view showing a thickness discriminating unit in the plastic sorting apparatus according to Embodiment 4 of the present invention,
16 is a perspective view showing a thickness discriminating portion in a plastic sorting apparatus according to Embodiment 5 of the present invention,
17 is a diagram showing a device configuration for detecting the presence of cancellation and performing a process for removing the cancellation-containing plastic by using the apparatus according to Embodiment 3 of the present invention.

Embodiment 1

BRIEF DESCRIPTION OF THE DRAWINGS Fig. 1 is a flowchart showing a method of selecting plastics according to a method for producing recycled plastics according to Embodiment 1 of the present invention. Fig. 1, the specific gravity value is set to a predetermined value P1 (here, P is an upper case letter in Greek letters), and P1 is set to 1.0 so that the first specific gravity selection is carried out, Plastics and metals that are heavier than 1.0 are selected.

The mixed shredded plastic is made mainly of polypropylene (PP), polystyrene (PS), acrylonitrile butadiene styrene (ABS), and other small amounts of polyacetal (POM) and polybutylene terephthalate (PBT) . PP has a specific gravity of about 0.9, which is lighter than PS (about 1.05), ABS (about 1.05) or other plastic, and is distinguished by the first specific gravity. By removing the canned PP from the PP separated by specific gravity sorting, the RoHS compliant PP is recovered.

The substances subject to RoHS are lead, mercury, cadmium and hexavalent chromium in addition to cancellation flame retardants. However, as a result of the investigation of PP after screening for specific gravity, no substance has fallen below the regulated content. Therefore, by removing the cancellation-containing PP, the RoHS-compliant PP is recovered.

Fig. 2 shows a configuration of the adiabatic sorting apparatus as a specific example of the specific gravity selecting method.

The main body of the adhering sorting apparatus comprises an infiltrating water tank 2 capable of storing the liquid medium 9, a paddle 3 for stirring and conveying suspended matters, and a screw conveyor 5a for conveying the sediment. The mixed crushing plastic is dispersed and introduced into the liquid medium as indicated by the flow of the arrow 8 in the constant amount feeding device 1. The suspended matter in the mixed crushing plastic is conveyed onto the liquid medium by the paddle 3, 4, and as shown by the arrows in the flow 10 of the floating sorting material, the floating sorting material is recovered. By using water (specific gravity = 1.0) as the liquid medium, only PP (specific gravity? 0.9) having a specific gravity smaller than that of water can be recovered from the mixed crushing plastic as a floating sorting material. In addition, the floating sorting material is recovered, and the remaining liquid medium 13 is returned to the submerging water tank 2 by the pump attaching tank 7.

On the other hand, the sediment having a specific gravity larger than that of water is conveyed to the screw conveyor 5a and then discharged as a liquid medium and sediment, as indicated by the arrow 11 showing the flow of the liquid medium and sediment from the discharge port 6a. 2, the discharged sediment and the liquid medium are lifted upward by the screw conveyor 5b from the surface of the liquid medium once stored in the submerged water tank 2. As shown in Fig. As a result, the liquid medium is returned to the infiltrating bath 2, and only the sediment shown by the arrow 12 is recovered from the discharge port 6b and the selection is completed.

Fig. 3 shows the structure of the apparatus as a specific example of the canceling-containing plastic removing method. 3, the crushing plastic 22 (consisting of the cancellation-containing plastic 22a and the cancellation-free plastic 22b) is sequentially supplied from the supply device 23 to the transporting device 21. As shown in Fig. The crushed plastic 22 which is accelerated in the transfer device 21 protrudes from the transfer device 21 and is guided to the X-ray tube 24 (X-ray irradiator, hereinafter referred to as X-ray irradiator And an X-ray detector 25 provided at a position opposite to the X-ray irradiation source. The X-ray generated from the X-ray tube 24 is irradiated to the crushed plastic 22, and the transmitted X-ray is detected by the X-ray detector 25. The data processing section 26 discriminates the cancellation content and the non-content in the data processing section 26 and the cancellation containing plastic 22a in the sorting mechanism 27 is stored in the cancellation containing plastic storage box 28, The box 29 is discriminated.

An X-ray line sensor, an X-ray imaging intensifier, an X-ray CCD camera, an X-ray scintillator, and an X-ray detector capable of measuring X- An X-ray detector 25 having no energy decomposition function such as a sensitivity type proportional counter tube is used. When these detectors are used, the position of the cancellation-containing plastic 22a can be specified because the transmitted X-ray intensity becomes weak at the position of the cancellation-containing plastic 22a. Further, by using these detectors, it is possible to make the visible image of the X-ray intensity distribution in the line or plane. In the visualized image, the cancellation-containing plastic 22a is displayed smaller in brightness than the cancellation-free plastic 22b.

Plasma containing a filler (talc, clay, calcium carbonate, etc.), a reinforcing material (glass fiber), and a coloring agent (titanium oxide, etc.) also have weak transmittance X-ray intensity, Therefore, they are excluded in advance by gravity selection, and the degree of discrimination does not deteriorate. Further, the operation load of the sorting mechanism 27 can be reduced, and the degree of discrimination is improved.

For example, a belt conveyor or the like may be used as the conveying device 21, and a hopper, a feeder, or the like may be used as the feeding device 23 for the object to be separated to the belt conveyor. The sorting mechanism 27 may be accommodated in a storage box suitable for the suction by a suction nozzle or the like by air blow or vacuum based on a signal from the data processing unit or may be transferred to the next belt conveyor.

As described above, in the method for producing a recycled plastic according to the present embodiment, the presence of the cancellation is detected at the rear end and the step of removing the cancellation-containing plastic is provided. It can be widened and the recovery rate of RoHS-compliant PP can be improved.

Embodiment 2

4 is a flowchart showing a method for producing a recycled plastic according to Embodiment 2 of the present invention. In Fig. 4, the mixed-crushing plastic is set to the specific gravity value P1 previously determined in the process of the first specific gravity selection, and the specific gravity selection is carried out. Here, P1 is selected to be 1.0, PP selected to be lighter than 1.0 specific gravity, and plastic and metal having a specific gravity higher than 1.0. Next, the second specific gravity selection is performed by setting the plastic having the specific gravity greater than 1.0 to a predetermined specific gravity threshold value (P2). Here, the mixture of PS and ABS, which is slightly lighter than 1.1, and plastic and metal whose specific gravity is greater than 1.1 are selected as P2 and 1.1, respectively. By selecting the second specific gravity, the mixture of PS and ABS selected to be lighter than the specific gravity of 1.1 is charged by friction or the like, and PS and ABS are selected from the electrostatic system by using different charging characteristics of PS and ABS. By the apparatus for removing the canceling plastics described in Fig. 3 from PS and ABS after electrification, cancellation PS and ABS are removed, and RoHS compliant PS and ABS are recovered.

As a result of investigation of PS and ABS after electrostatic screening, any substance such as lead, mercury, cadmium and hexavalent chrome is under regulated content. Therefore, by removing the canceling PS and ABS, PS and ABS of RoHS compliance are recovered.

In the first embodiment, the structure of the adhering separator using water (specific gravity = 1.0) as the liquid medium is described as a specific example of the specific gravity selecting method in which the specific gravity value is set to 1.0, but when the specific gravity value is set to 1.1 Replaces the liquid medium with a liquid capable of setting a specific gravity, such as brine, chlorinated organic solvent or the like.

Fig. 5 shows a configuration of the electrostatic screening apparatus. The electrostatic sorting apparatus is provided with a fixed quantity supply device 30, a friction stir piece 31, an electric field supply device 32, counter electrodes 33a and 33b, power supplies 34a and 34b and recovery boxes 35a and 35b have.

In the fixed amount supply device 30, a mixture of PS pieces and ABS pieces selected by specific gravity selection is introduced. In Fig. 5, & cir & indicates the ABS part and & cir & indicates the PS part. PS and ABS have different positions in the charging sequence, PS is located on the negative side in the charging sequence, and ABS is on the positive side in the charging sequence.

The friction stir piece 31 supplied with the mixture of the PS piece and the ABS piece from the fixed amount supply device 30 is a rotatable cylindrical stirring container. The tread band 31 is rotatable about its central axis as a rotation center, and frictionally stirs the mixture 40 of the PS piece and the ABS piece by rotating to charge the mixture. The electric field injecting device 32, which has been supplied with the charged mixture more than the friction stirrer 31, has a function of sending the mixture to the opposing electrodes 33a and 33b.

A lower potential than the power source 34a is applied to the counter electrode 33a (negative electrode), and a higher potential than the power source 34b is applied to the counter electrode 33b (positive electrode). As a result, an electric field is generated between the counter electrodes 33a and 33b, and the charged mixture passes through the portion where this electric field is generated. Of the charged mixture, the negatively charged PS piece is attracted to the opposing electrode 33b at the higher potential side, and the ABS piece charged at the positive side can be attracted to the opposing electrode 33a at the lower potential side. The PS piece is sorted and collected in the recovery box 35b on the high potential side and the ABS piece on the recovery box 35a on the low potential side.

The configuration example of the device for performing the cancellation-containing plastic removal is the same as the configuration of the device for executing the cancellation-containing plastic removal according to the first embodiment. Therefore, the description of this portion is omitted.

Here, a specific gravity selecting method in Embodiment 1 and Embodiment 2 will be described. 6 is a graph showing an example of the distribution of specific gravity of PP and PS / ABS occupying most of the plastic recovered in the market. The thick line indicates PP and the thin line indicates PS ㆍ ABS. The specific gravity of PP is distributed around 0.9 in this example, and the specific gravity of PS · ABS is distributed around 1.05. Fig. 7 is a graph showing the average cancellation concentration in the plastic with respect to specific gravity in the plastic of this example. Fig. The bold line shows the target value after the cancellation-containing plastic is removed, and the fine line after the cancellation-containing plastic is removed with the cancellation-containing plastic removal device of FIG. The target value is 300ppm. If the cancellation concentration is less than 300 ppm, it is a value that can guarantee less than 1000ppm (RoHS conformance) as a compound even in canceled flame retardants subject to any RoHS Directive. In the graph prior to the removal of the plastic containing the cancellous contents, the average cancellation concentration of the specific gravity of 1.0 to 1.05 is the cancellation content PP, and the cancellation concentration of the specific gravity of 1.1 or more is the cancellation containing PS ABS. Since cancellation is heavier than plastic, the specific gravity of plastic increases when added to plastic.

PPs separated by specific gravity selection of specific gravity value 1.0 will have a cancellation concentration of less than 300 ppm even without performing the cancellation of plastic removal. PS ㆍ ABS includes canceled PP, but it can be distinguished by electrostatic screening at the rear end. In the electrostatic separation described above, the PS is referred to as the separation of ABS, but the PS after electrification includes the cancellation-containing PP. Since PS and PP have different charging characteristics, PS and PP can be discriminated by performing further electrostatic separation. However, since the cancellation-containing PS and ABS can not be distinguished by electrostatic separation, if the method of performing the cancellation of the cancellation-containing plastic is not used by detecting the cancellation as described in Fig. 3, You need to remove it. In order to remove the cancellation plastics by specific gravity sorting, referring to Fig. 7, for example, the non-specific gravity value 1.1 is too large and the specific gravity value is less than 1.1, for example, 1.07, There is a need. On the other hand, when the cancellation-containing plastic is removed by detecting the cancellation as described with reference to Fig. 3, the cancellation-containing PS and ABS can be discriminated at the subsequent stage, so that the specific gravity value can be increased. That is, the screening threshold value P2 for the second specific gravity screen in the second embodiment is increased (1.1 in the second embodiment), and the amount of plastic removed by the second specific gravity screen can be reduced. Fig. 8 is a graph showing the recovery rates of PP and PS 占. B when specific gravity is selected by setting the specific gravity threshold in the specific gravity sorting as the abscissa axis. As can be seen from FIG. 8, in PP, the recovery rate is almost 100% when the specific gravity threshold is 1.0. On the other hand, in PS ㆍ ABS, for example, when the specific gravity value is set to 1.1, the recovery rate becomes 90% or more. In order to remove the canceled plastics by specific gravity sorting, There is an effect that can be improved.

The specific gravity value (P1) for the first specific gravity point in the first and second preferred embodiments and the specific gravity point value (P2) for the second specific gravity point in the second preferred embodiment are determined as follows. As described in Embodiment 1, among the plastics which are the main bodies in the mixed crushing plastic in which plastics having different specific gravity distributions are mixed, that is, the plastics to be fractionated, the gravity of the plastic having the smallest specific gravity (lightness) such as PP (polypropylene) P 1 is determined based on the distribution. In the case where the lightest plastic is PP, the P1 is preferably 1.0 is described in Embodiment 1 or above. Next, the specific gravity of the plastic to be discriminated (including a plurality of plastics whose specific gravities are close to each other such as PS and ABS) and the other fillers (talc, mud , Calcium carbonate, etc.), a reinforcing material (glass fiber), a coloring agent (titanium oxide, etc.), and the like, P2 is determined so that the ratio becomes a predetermined value or less.

As described above, in the method of manufacturing recycled plastics according to the present embodiment, the step of removing the cancellation-containing plastic by detecting the presence of cancellation at the rear end is provided, whereby the specific gravity range of the to- Can be RoHS compliant It can improve the recovery rate of PP, PS, ABS.

Embodiment 3

Although the plastic sorting method according to the recycling plastic manufacturing method has been described in the above embodiment, by using the plastic sorting apparatus according to Embodiment 3 of the present invention in the plastic sorting method in the above embodiment, (Hereinafter also referred to as " plastic piece ") of a mixed plastics material having a different thickness is made to penetrate the plastic piece selected by the thickness selecting means It is possible to prevent erroneous determination due to the thickness of the plastic piece by detecting the transmittance of each of the X-rays and sorting the plastic pieces for each thickness selection based on the data of the transmitted X-rays and the thickness data in the thickness selection means, Even plastic pieces having various thicknesses can be selected with high accuracy. Therefore, more precise sorting becomes possible, and the specific gravity of the object to be sorted can be widened by appropriately setting the specific gravity threshold value for each specific gravity, thereby further improving the recovery rate of the RoHS-compliant PP, PS and ABS.

A plastic sorting apparatus according to a third embodiment for carrying out the present invention will be described with reference to Figs. 9 to 13. Fig. 9, the plastic sorting apparatus 50 includes a hopper 59 serving as a feeding device for feeding the plastic piece 51, a thickness selecting section 52 for sorting the plastic piece 51 by thickness, A belt conveyor 53 as a conveying device and an X-ray irradiator 54 for irradiating the plastic piece 51 with X-rays, that is, an irradiating means, A discrimination device 56 for discriminating the plastic piece 51 based on the thickness information of the X-ray detector 55 to be detected, that is, the detecting means, the thickness discriminating portion 52 and the transmittance of the detected X- (Air blow) 57 as a sorting mechanism for separating the plastic piece 51 based on the discrimination result, that is, the plastic piece 51 separated by the separation part and the air gun 57, A recovery container 58a for recovering a plastic piece 51a (sometimes classified as a non-canceled plastic) containing cancellation, And a recovery container 58b for recovering a plastic piece 51b (which may be classified with a canceling-containing plastic) containing a cancellation amount larger than a predetermined value.

10, the thickness selecting section 52 is provided at a lower portion of the hopper 59, and includes a sliding section 61, that is, a sliding member, which is inclined in the longitudinal direction and the width direction, The side walls 62a and 62b formed respectively in the longitudinal direction and the partition plates 63a and 63b for sorting the thickness of the plastic piece 51, that is, the sorting member and the partition plates 64a and 64b ), That is, a partitioning member.

Further, although the slide 61 is inclined in the longitudinal direction and the width direction, it may be inclined only in the longitudinal direction.

The slide 61 is provided with a plastic supply portion 61a on the side where the inclination is high in the longitudinal direction and a discharge portion 61b on the side where the inclination is low and the side wall 62b provided on the low- One end of the discriminating plates 63a and 63b is bonded or welded. 11, the sorting plates 63a and 63b extend toward the discharge portion 61b of the plastic, and at the same time, the plastic pieces of less than a desired thickness are passed between the slide plates 61 The passages 65a and 65b are formed. The passing portion 65a is provided on the side having a higher opening height than the passing portion 65b and a higher inclination in the width direction of the slide 61.

Although two sheet discrimination boards are used here, the number of sheet discrimination boards is not limited to this, and a thin thickness discrimination can be performed as much as the number of sheets is large.

The partition plates 64a and 64b are adhered or welded to the other ends of the sorting plates 63a and 63b so as to contact the inclined surface of the slide 61 so that the thickness of the plastic pieces 51 does not co- (61b). The slide 61 is provided with a vibration device (not shown, but not limited to, a vibration device as disclosed in Japanese Patent No. 3035280, for example) for applying vibration to the plastic piece 51 have. Further, although the partition plates 64a and 64b and the sorting plates 63a and 63b are formed separately, they may be formed of one plate.

An X-ray irradiating source 54 for irradiating the plastic piece 51 with X-rays during the conveying path of the belt conveyor 53, Ray detector 55 for detecting the transmittance of the X-rays transmitted through the plastic piece 51 for each of thicknesses selected by thickness. As the X-ray detector 55, an X-ray line sensor capable of measuring the X-ray intensity distribution in a line is used, but it is also possible to use an X-ray line sensor capable of measuring the intensity distribution of X- Fire, an X-ray CCD camera, an X-ray scintillator, a position sensitive type proportional counter, etc.) may be used.

The transmittance of the X-rays detected by the X-ray detector 55 corresponds to the thickness information of the thickness discriminating portion 52, that is, the passage height information of the passing portions 65a and 65b formed in the discriminating plates 63a and 63b, The discrimination device 56 compares the transmittance of the X-rays detected with the determination reference value set on the basis of the thickness information, and outputs the plastic piece 51a Based flame retardant), and outputs the result as a control signal of the air gun 57. The air gun 57 outputs a control signal to the air gun 57,

The air gun 57 is provided at the end of the belt conveyor 53 and is provided with a plastic piece 51a (containing a canceling flame retardant below a predetermined value) and a plastic piece 51b in accordance with a control signal received from the discriminating device 56. [ (Containing more than the predetermined value of the canceling flame retardant). At the fall position of the ejected plastic pieces 51a, 51b, there are provided recovery containers 58a, 58b arranged forward, backward, or laterally depending on the ejection direction.

Next, the operation will be described. The plastic piece 51 having various thicknesses (for example, 0.5 mm or more and 3 mm or less in thickness) supplied from the hopper 59 to the supply part 61a of the slide 61 is moved by the oscillation device to the slide 61, And the slant surface of the slide 61 is moved toward the discharge portion 61b of the plastic piece as shown by the arrow in Fig. 11, and thickness of the slide plate 61 is selected by the plates 63a and 63b .

12, when the height of the passing portions 65a, 65b is 2 mm and 1 mm respectively from the side closer to the supply portion 61a of the slide 61, The thickness of 0.5 mm or more and less than 1 mm passes through the passing portions 65a and 65b and the thickness of 1 mm or more and less than 2 mm passes through the passing portion 65a but does not pass the passing portion 65b, The plastic piece 51 of 2 mm or more and 3 mm or less does not pass through any of the passing portions 65a and 65b.

As a result, the plastic pieces 51 are sorted into three types (thicknesses of 0.5 mm or more and less than 1 mm, less than 1 mm and less than 2 mm, or between 2 mm and 3 mm) for each thickness.

The three kinds of plastic pieces 51 selected for each thickness in this way are the same as those of the side walls 62a and 62b and the partition plates 64a and 64b 62b and a partition plate 64b having a thickness of 1 mm or more and less than 2 mm are divided into partition plates 64a and 64b and those having a thickness of 2 mm or more and 3 mm or less are partitioned by a side wall 62a and a partition plate 64a The slope of the slide 61 is moved, and the plastic piece is discharged from the discharge portion 61b. Thereafter, the discharged plastic piece 51 is conveyed by the belt conveyor 53 and irradiated with X-rays when passing through the irradiation area of the X-ray irradiation source 54. Among the irradiated X-rays, the X-ray transmitted through the plastic piece 51 is detected by the X-ray detector 55 for each thickness of the thickness discriminating portion 52, and the position information indicating the transmittance is detected, 56.

Based on the thickness information based on the positional information, the determination device 56 determines the determination reference value among the transmittances of X rays set in advance and compares the determined reference value with the transmittance of the X-rays detected by the X-ray detector 55 A plastic piece 51a (containing a canceled flame retardant of a predetermined value or less) is detected if the detected X-ray transmittance is equal to or greater than the judgment reference value, and a plastic piece 51b (containing a canceled flame retardant more than a predetermined value) And transmits a control signal to the air gun 57. [

When the air gun 57 receives the control signal from the discriminating device 56, the plastic piece 51 conveyed by the belt conveyor 53 to the injection port of the air gun 57 is conveyed to the plastic Is mechanically separated into flakes 51a (containing flame retardant of a predetermined value or less) and plastic flakes 51b (containing flame retardant of more than a predetermined value), and recovered into the respective recovery containers 58a and 58b.

Here, the discrimination method of the discrimination device 56 will be described in detail with reference to Fig.

14 is a graph showing the transmittance of X-rays according to the thickness of the plastic piece, and shows that the cancellation content is 0 mass% and 1 mass% (the X-ray transmittance is 1 for the X- Quot; refers to a value obtained by normalizing the X-ray dose transmitted through the sample).

Even if the cancellation content is 0 mass%, the transmittance of the X-ray does not become 1 because carbon such as a component of the plastic material absorbs X-rays. Therefore, the decrease of the X-ray transmittance causes not only an increase in content of cancellation, .

As the determination reference value for the plastic piece 51 of a predetermined thickness, it is preferable to select a plastic piece 51 having a desired cancellation content ratio or less. 14, in order to determine the plastic piece 51a having a thickness of 0.5 mm or more and less than 1 mm and a cancellation content of 1 mass% or less, it is necessary to determine the transmittance of X-rays at a thickness of 0.5 mm and a cancellation content of 1 mass% It may be a reference value. At this time, the X-ray transmittance of the plastic piece 51b (the cancellation content is higher than 1 mass%) in a predetermined thickness range (0.5 mm or more and less than 1 mm) Can be distinguished.

Similarly, when the thickness of the plastic piece is 1 mm or more and less than 2 mm or less than or equal to 2 mm and less than or equal to 3 mm, the determination reference values may be set to the thicknesses of 1 mm and 2 mm, respectively, and the transmittance of X- As a result, the discriminating device 56 can discriminate the plastic pieces 51a and 51b for each thickness of thickness discrimination.

The reason why the transmittance of X-ray of 1 mass% in cancellation content is used as the above-mentioned criterion is as follows. The recycled resin which was unsuitable for the RoHS directive was examined through conventional material selection, and a plastic piece having a cancellation content exceeding 1% by mass was mixed at a ratio of several to 20 pieces per 1000 plastic pieces after the selection. The plastic pieces having a cancellation content exceeding 1% by mass were removed from these plastic pieces, and the recycled resin was suitable for the RoHS directive. Therefore, in this embodiment, the X-ray transmittance with a cancellation content of 1% by mass was adopted as a determination reference value.

17 is a specific example of a case where the plastic sorting apparatus according to Embodiment 3 of the present invention is used as a concrete example of the cancellation containing plastic removing method using the X-ray of Embodiment 1 shown in Fig. 3 / RTI > The X-ray irradiating position, the X-ray detecting position, and the air gun 57 may be arranged in such a manner that the air gun 57 is lifted off in a manner that the plastic gun screening apparatus shown in Fig. Is different from that at the rear of the belt conveyor 53 at one point.

According to this embodiment, the plastic pieces 51 having various thicknesses are selected for each thickness, and then the plastic pieces 51 are irradiated with X-rays to detect the transmittance for each selected thickness, and the detected X The plastic piece 51a containing the cancellous flame retardant of a predetermined value or less is selected based on the discrimination result and the thickness of the plastic piece 51 It is possible to prevent erroneous determination caused and select it with high screening accuracy. Particularly, compared with the case where the content of the canceling flame retardant is as low as 10 mass% or less and the determination is made based only on the X-ray transmittance, the plastic piece 51 can be selected with high accuracy of discrimination because the determination reference value based on the thickness information is used.

The thickness discriminating portion 52 uses the discriminating plates 63a and 63b for forming the passing portions 65a and 65b through which the plastic piece 51 having a thickness smaller than the desired thickness passes, The thickness of the plastic piece 51 can be easily selected.

Since the thickness discriminating portion 52 is inclined in the longitudinal direction and the width direction in the thickness direction discriminating portion 52 so that more plastic pieces 51 spread on the inclined surfaces and move on the sliding table 61, ) Can be improved.

Since the vibrating device is provided in the thickness selecting part 52, the vibrating plastic piece 51 becomes a scattered single-layer state and moves on the slide 61, so that the degree of thickness selectivity of the plastic piece 51 Can be further improved.

Further, by providing the partition plates 64a, 64b on the downstream side of the thickness discriminating portion 52, it is possible to prevent the plastic pieces 51 once sorted once again from being mixed together, thereby improving the degree of thickness discrimination.

Embodiment 4

Fig. 15 shows another embodiment of the thickness selecting unit according to the present invention. 15, the thickness discriminating portion 70 is provided with a first sliding part 71a having a slope in the longitudinal direction and the width direction, that is, a sliding part, and a slip part provided on the side in the longitudinal direction of the first sliding part 71a, A side wall 72a having a supply portion, an opposite plate 73 facing the first slide 71a, and a slope 75a in the longitudinal direction of the first slide 71a, A side wall 72b provided on the side in the longitudinal direction of the second slide member 71b and a side wall 72b provided on an inclined surface of the second slide member 71b and provided with a plastic piece And a partition plate 74 for dividing the compartments 51 into the compartments. In addition, a vibration device (not shown) for applying vibration to the plastic piece 51 is provided in the first slide 71a.

The opposite plate 73 has a larger inclination in the width direction than the first slide 71a and a passing portion 76 through which the plastic piece 51 of less than a desired thickness passes is formed, And has a wedge shape that is wide enough to be close to the convenience feed port 75.

The partition plate 74 provided on the inclined surface of the second slide base 71b extends along the inclination to prevent the plastic pieces 51 whose thicknesses are selected in the passing portion 76 from being mixed again.

Next, the operation will be described.

The plastic pieces 51 having various thicknesses supplied from the supply opening 75 of the plastic piece to the first slide 71a are in a single layer state in which vibration is applied via the first slide 71a by the vibration device , The inclined portion of the thin plastic piece 51 moves along the wedge shape formed in the width direction of the passing portion 76. [ The plastic pieces 51 are arranged in the order of their width in the width direction and move to the second slide base 71b along the inclination of the passing portion 76, respectively.

The plastic piece 51 moved to the second slide 71b moves in a direction indicated by an arrow in the figure by the inclined surface surrounded by the side wall 72b and the partition plate 74 according to the selected thickness and is discharged to the belt conveyor 53 . The plastic piece 51 discharged to the belt conveyor 53 is then sorted in the same manner as in the first embodiment.

According to this embodiment, the thickness discriminating portion 70 is provided with the wedge-shaped passage portion (in the width direction) by using the first sliding piece 71a inclined in the longitudinal direction and the width direction and the opposing plate 73 arranged to face the first sliding piece 71a 76), it is possible to easily select the thickness of the plastic piece with a simple structure. Since the thickness for thickness selection is determined by the shape of the passing portion 76, it is possible to sort the plastic pieces 51 into a plurality of kinds with a small number of parts.

Embodiment 5

Fig. 16 shows still another embodiment of the thickness selecting unit according to the present invention. 16, the thickness discriminating portion 80 is provided on the first slide 81a having a slope in the longitudinal direction and the width direction, that is, on the side in the longitudinal direction of the sliding member and the first slide 81a, A supply port 85 for supplying the plastic piece 51 to the first slide 81a, that is, a side wall 82a having a supply portion, an opposite plate 83 facing the first slide 81a, A second slide 81b mounted on the lower side of the slope 81b and a side wall 82b provided on the side in the longitudinal direction of the second slide 81b and a slope of the second slide 81b, And a partition plate 84 for dividing the upper and lower plates 51 and 51. Further, a vibration device (not shown) for applying vibration to the plastic piece 51 is provided in the first slide 81a.

The opposite plate 83 has a stepped shape in the width direction and has a through-hole for passing the plastic piece 51 having a thickness smaller than the desired thickness so that the side closer to the supply port 85 of the plastic piece is widened with respect to the first slide 81a. (86).

The partition plate 84 provided on the inclined surface of the second slide 81b extends along the inclination to prevent the plastic pieces 51 whose thickness is selected in the passing portion 86 from being mixed again.

Next, the operation will be described.

The plastic pieces 51 having various thicknesses supplied from the supply opening 85 of the plastic piece to the first slide 81a are subjected to vibration through the first slide 81a by the vibration device to become a one- , The slope moves toward the lower slope by the thin plastic piece 51 along the stepped shape formed in the width direction of the passing portion 86. The plastic pieces 51 are arranged in the order of thickness of the end portions in the width direction and move to the second slide base 81b in accordance with the inclination of the passing portion 86, respectively.

The plastic piece 51 moved to the second slide 81b moves the inclined surface surrounded by the side wall 82b and the partition plate 84 in the direction of the arrow in the drawing according to the selected thickness and discharges it to the belt conveyor 53 do. The plastic piece 51 discharged to the belt conveyor 53 is then sorted in the same manner as in the first embodiment.

According to this embodiment, the thickness discriminating portion 80 is provided with the step portion 81 in the width direction by using the first sliding piece 81a inclined in the longitudinal direction and the width direction and the opposing plate 83 arranged opposite thereto, 86), it is possible to easily select the thickness of the plastic piece with a simple structure. Further, since the thickness for thickness selection is determined by the shape of the passing portion 86, it is possible to sort the plastic pieces 51 into a plurality of kinds with a small number of parts.

1: Quantitative feeder 2: Feeding tank
3: Paddle 4: Vibrator
5a to 5b: Screw conveyor 6a to 6b:
7: tank with pump 8: flow of mixed crushed plastic
9: liquid medium 10: flow of float sorting water
11: Flow of liquid medium and sediment 12: Flow of sediment
13: Flow of recovered liquid medium 21:
22: shattered plastic 22a: canceled plastic
22b: Cancellation-free plastic 23: Supply device
24: X-ray tube 25: X-ray detector
26: Data processing unit 27:
28: Storage box of plastic containing cancellation
29: Storage box of plastic without cancellation
30: Quantitative feeder 31: Friction vs. Tradition
32: electric field applying device 33a, 33b: opposing electrode
34a, 34b: power source 35a, 35b: collection box
40: Mixture of PS pieces and ABS pieces 50: Plastic sorting device
51: Plastic piece
51a: a plastic piece containing a flame retardant at a predetermined value or less;
51b: a plastic piece containing a canceling flame retardant greater than a predetermined value
52: Thickness selector 53: Belt conveyor
54: X-ray irradiator 55: X-ray detector
56: discrimination device 57: air gun
58a: Collection container 58b: Collection container
59: Hopper 61: Slide
62a: side wall 62b: side wall
63a: discriminating plate 63b: discriminating plate
64a: partition plate 64b: partition plate
65a: passing portion 65b: passing portion
70: thickness selector 71a: first slide
71b: second slide 72a: side wall
72b: side wall 73: facing plate
74: partition plate 75: supply port
76: passing portion 80: thickness selecting portion
81a: first slide 81b: second slide
82a: side wall 82b: side wall
83: facing plate 84: partition plate
85: feed port 86:

Claims (9)

In a plastic sorting method,
A first specific gravity separating step of discriminating a plastic which is lighter than the first specific gravity threshold value (P1) based on the specific gravity distribution of the light plastic to be discriminated from the mixed crushing plastic by gravity selection;
A detection step of irradiating an X-ray from an X-ray source onto a separated light plastic and detecting the intensity of the X-ray transmitted through the separated light plastic by an X-ray detector,
A discriminating step of analyzing data on the intensity of the transmitted X-rays to discriminate the presence or absence of cancellation (bromine) in the discriminated light plastic;
And a cancellation-containing plastic removing process for removing the cancellation-containing plastic from the discriminated light plastic by the presence or absence of cancellation
Plastics sorting method. The method according to claim 1,
The detecting step is a step of irradiating the X-ray to the separated light plastic in the air between the X-ray source for irradiating the X-ray source and the X-ray detector provided for the X-ray source, And the intensity of the X-ray is detected by an X-ray detector
Plastics sorting method. 3. The method according to claim 1 or 2,
Wherein the detecting step is a step of irradiating the X-ray to the separated light plastic in the air between the X-ray source for irradiating the X-ray and the X-ray detector provided for the X-ray source, And detecting the intensity of the line on a line (line) or a plane (surface) simultaneously by a plurality of X-ray detectors
Plastics sorting method. In a plastic sorting method,
A first specific gravity separating step of discriminating a plastic which is lighter than the first specific gravity threshold value (P1) based on the specific gravity distribution of the light plastic to be discriminated from the mixed crushing plastic by gravity selection;
The specific gravity distribution of the plastic which is heavier than the first specific gravity threshold value (P1) and the specific gravity of the material which can not be classified by the gravity selection method from the plastic heavier than the first specific gravity threshold value (P1) A second specific gravity separating step of discriminating a plastic which is lighter than the second specific gravity threshold value P2,
A electrostatic separation step of separating the plastics classified by the second specific gravity separating step by the electrostatic separation method according to the material of the plastic,
A detection step of irradiating X-rays from the X-ray source onto the plastic separated by the electrostatic separation step and detecting the intensity of the X-rays transmitted through the plastic separated by the electrostatic separation step by an X-ray detector;
A discriminating step of analyzing data on the intensity of the transmitted X-rays and discriminating the presence or absence of cancellation in the plastic separated by the electrostatic screening step;
And a cancellation-containing plastic removing step of removing the cancellation-containing plastic from the plastic separated by the electrostatic sorting step by the presence or absence of cancellation
Plastics sorting method. 5. The method of claim 4,
Wherein the detecting step irradiates the X-ray to the plastic separated by the electrostatic separation step in the air between the X-ray source for irradiating the X-ray source and the X-ray detector provided for the X-ray source, And the intensity of the X-rays transmitted through the plastic separated by the X-ray detector
Plastics sorting method. The method according to claim 4 or 5,
Wherein the detecting step irradiates the X-ray to the plastic separated by the electrostatic separation step in the air between the X-ray source for irradiating the X-ray source and the X-ray detector provided for the X-ray source, Is a step of simultaneously detecting the intensity of X-rays transmitted through the plastic separated by the X-ray detector
Plastics sorting method. 5. The method of claim 4,
The second non-specific gravity selecting step is a step of selecting, from a plastic heavier than the first specific gravity threshold value (P1) discriminated in the first gravity selecting step, a specific gravity distribution of the plastic heavier than the first specific gravity value (P1) Characterized in that it is a step of discriminating plastics that are lighter than the second specific gravity threshold value (P2) of not less than 1.07 and not more than 1.1 based on the specific gravity of the non-
Plastics sorting method. In a plastic sorting apparatus,
A first specific gravity discriminating means for discriminating a plastic which is lighter than the first specific gravity threshold value (P1) based on the specific gravity distribution of the light plastic to be discriminated from the mixed crushed plastic by a specific gravity selecting method,
An irradiating means for irradiating X-rays from the X-ray source onto the separated light plastic,
Detecting means for detecting the intensity of X-rays transmitted through the discriminated light plastic,
Discriminating means for analyzing data on the intensity of the transmitted X-rays detected by the detecting means and discriminating the presence or absence of cancellation in the discriminated light plastic;
Characterized in that it comprises a cancellation-containing plastic removing means for removing the cancellation-containing plastic from said discriminating light plastic by the presence or absence of cancellation
Plastic sorting device. In a plastic sorting apparatus,
A first specific gravity discriminating means for discriminating a plastic which is lighter than the first specific gravity threshold value (P1) based on the specific gravity distribution of the light plastic to be discriminated from the mixed crushed plastic by a specific gravity selecting method,
The specific gravity distribution of the plastic heavier than the first specific gravity threshold value (P1) and the specific gravity of the material not to be classified by the gravity selection method from the plastic heavier than the first specific gravity threshold value (P1) discriminated by the first specific gravity selecting means Second specific gravity selecting means for classifying plastic which is lighter than the second specific gravity threshold value (P2)
Electrostatic screening means for sorting the plastics classified by the second specific gravity screening means into materials of plastics by electrostatic separation;
Detecting means for irradiating the X-ray from the X-ray source onto the plastic separated by the electrostatic detecting means, and detecting the intensity of X-rays transmitted through the separated plastic,
Discriminating means for analyzing data on the intensity of the transmitted X-rays and discriminating the presence or absence of cancellation in the plastic separated by the electrostatic screening means;
Characterized in that it comprises a cancellation-containing plastic removing means for removing the cancellation-containing plastic from the plastic separated by the electrostatic screening means by the presence or absence of cancellation
Plastic sorting device.

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