CN105636703A - Triboelectrostatic separation method for material separation of abs and ps mixed waste plastic - Google Patents

Abstract

The present invention relates to a triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials. Butadiene-styrene (ABS, Acrylonitrile? Butadiene? Styrene) and polystyrene (PS, Polystyrene) waste plastics recovery acrylonitrile-butadiene-styrene, using as a target sample of acrylonitrile-butadiene-styrene Material separation of mixed waste plastics of diene-styrene and polystyrene in polyethylene terephthalate, high-impact polystyrene and acrylonitrile-butadiene-styrene from effective charged substances A kind of triboelectric electrostatic screening experiment is carried out, and the experimental results show that under the optimal experimental conditions, the quality and recovery rate of acrylonitrile-butadiene-styrene are 99.5% and 92.5%, so that acrylonitrile-butadiene-styrene can be recovered. Butadiene-styrene and polystyrene blend plastic.

Description

Triboelectric electrostatic screening method for material separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastics

technical field

The present invention relates to a triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials. Butadiene-styrene (ABS, AcrylonitrileButadieneStyrene) and polystyrene (PS, Polystyrene) waste plastics recovery acrylonitrile-butadiene-styrene, using as a target sample of acrylonitrile-butadiene-styrene Material separation of mixed waste plastics of ethylene and polystyrene The acrylonitrile-butadiene-styrene material, which is an effective charged substance, performs a triboelectric electrostatic screening experiment. The experimental results show that, under the optimal experimental conditions, acrylonitrile-butadiene-styrene material The quality and recovery rate of butadiene-styrene are 99.5% and 92.5%, respectively, so that mixed plastics of acrylonitrile-butadiene-styrene and polystyrene can be recycled.

Background technique

Generally, plastics can replace trees, metals, and other substances. Plastics are not only light, strong, and easy to process, but also have excellent chemical properties such as corrosion resistance and insulation, so they are widely used in daily life and industrial fields. At present, with the advent of engineering plastics and various special plastics formed from functional polymers, it has caused the "second plastic revolution" and continued to expand the scope and amount of plastics used.

Due to the development of the petrochemical industry, South Korea has become the fourth largest plastic producer in the world following the United States, Japan, and Germany. The per capita plastic consumption has also reached the eighth in the world, and the per capita annual plastic consumption has reached about 100kg. Furthermore, since plastics have various excellent functions and economically low-cost characteristics, the amount of plastics used is increasing, resulting in an increasing amount of waste plastics. With the increase in the amount of plastic used, the amount of waste plastics also increased year by year according to the trend of 3458 thousand tons in 2003, 3968 thousand tons in 2005, and 4254 thousand tons in 2007. On the contrary, based on 2007 , The recycling rate of waste plastics is about 39%, and more than half of waste plastics are disposed of through landfill or incineration.

Usually, solid industrial waste is reduced in size by incineration and landfill, but the incineration and landfill methods of waste plastics not only cause economic losses, but also cause macroscopic causes of environmental pollution. Although part of the heat energy generated during the incineration process of waste plastics can be used, it will cause great economic losses, and the incinerator will be corroded due to hydrogen chloride, and the environment will be polluted due to the emission of various toxic gases such as benzene dioxide. question. Moreover, the landfill of waste plastics not only has the problem of securing a landfill site, but also has the problem of leaching out harmful components, reducing landfill efficiency due to excessive volume per unit weight, and causing refractory waste due to physical and chemical stability. Issues such as early stabilization of landfills and semi-permanent residues in the soil.

Therefore, the South Korean government began to implement the Extended Product Responsibility (EPR, Expended Product Responsibility) system in January 2003. For the sake of the plastics industry and environmental protection, there is an urgent need to develop recycling technology in terms of legally restricting the incineration and landfill of waste plastics in the future.

Compared with other substances, plastic is difficult to decompose and deteriorate, so as long as effective screening technology is developed, plastic can become one of the easiest substances to recycle. Techniques for recycling such waste plastics include energy recovery, chemical recovery, and material recovery methods, among which material recovery is the most effective method when considering the cheapness of plastics.

However, no matter what method is used, as long as other types of plastics are mixed, the physical properties will be greatly reduced. Therefore, in the process of recycling plastics, the material separation technology of plastics is the most important. At present, most plastics are recycled through remediation, but various fields are actively researching the separation technology of waste plastic materials, so great progress has been made in technology.

Generally, physical screening methods for recyclable waste plastics include electrostatic screening, dry specific gravity screening, wet specific gravity screening, flotation, color screening and spectroscopic methods.

prior art literature

1. ,2010: , ,12(2),pp.110-120, , , (Lee Seung-gyu et al., 2010: Waste Plastic Recycling and Green Production System Development, Disaster Prevention Research, 12(2), pp.110-120, Disaster Prevention Research Institute, National Institute of Disaster Prevention Education, Seoul, Korea).

2. etal. (Quan Huxi et al.), 2010: DevelopmentofElectrostaticSeparationTechniqueforRecoveryofSoftPVCfromMedicalPlasticWaste, J.ofKoreaSocietyofWasteManagement, 27(2), pp.159-164

3. Korean Patent No. 10-0835992 (application date: February 22, 2007)

4. Korean Patent No. 10-0809117 (application date: February 26, 2007)

5. Korean Patent No. 10-0848479 (application date: February 26, 2007)

6. Korean Patent No. 10-0836003 (application date: March 15, 2007)

7. Korean Patent No. 10-2013-0095921 (application date: February 21, 2012)

Contents of the invention

technical problem

The object of the present invention is to perform a mixed acrylonitrile-butadiene-styrene and polystyrene waste plastic using a triboelectric electrostatic screening method that can separate all materials regardless of conductive and non-conductive substances material separation.

Especially, the object of the present invention is to focus on reclaiming the large and expensive acrylonitrile-butadiene-styrene, and the recovery rate and quality of acrylonitrile-butadiene-styrene can reach 90% and 99% respectively. The screening technology with an efficiency of more than 100% establishes a material separation technology that can improve the recycling of mixed waste plastics.

means of solving problems

Referring to the accompanying drawings, the structure of the present invention having the above objects will be described in detail as follows.

The triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials of the present invention is characterized in that when different particles collide, rub or the particles When the surface of the charged device collides and rubs against each other to make use of the difference in work function to make electrons move to the direction in which the Fermi-level of the two substances gradually becomes the same, if the particles that are different from each other After the particles are in contact with the surface of the charged device, the particles are separated from the surface again, and there will be an excess or shortage of electrons. Therefore, if the particles are negatively charged (-) or positively charged (+), and the charged When charged mixed particles with opposite polarities pass through the high-voltage electric field, the particles with positive charge (+) move to negative charge (-), and on the contrary, the particles with negative charge (-) move to positive charge (+ ) to move, so as to realize the separation of waste plastics.

That is, charged substances for material separation of acrylonitrile-butadiene-styrene from waste plastics mixed with acrylonitrile-butadiene-styrene and polystyrene using a triboelectric charging type electrostatic screening method were composed of poly A composition of polyethylene terephthalate (PET), high-impact polystyrene (HIPS), and acrylonitrile-butadiene-styrene (ABS).

Invention effect

As mentioned above, in the case of recycling waste plastics, if mixed with various types of plastics, the material characteristics will be lowered, so it is difficult to recycle the materials, so it is necessary to separate waste plastics using material separation technology. In particular, when the demand for acrylonitrile-butadiene-styrene resin increases in various fields such as automobiles, electrics, and electronics, the production volume will increase, and at the same time, a considerable amount of waste plastic will be generated.

Therefore, in the present invention, crystals of charged substances suitable for material separation of waste plastics mixed with acrylonitrile-butadiene-styrene and polystyrene recovered from discarded household appliances are created by using a triboelectric charging type electrostatic screening method and The charging characteristics are used to find out the best screening conditions to maximize the charging efficiency and separation efficiency. Therefore, by contacting different particles or making the particles contact the surface of the charging device, the particles can be charged to different poles. It has the effect of being able to easily separate acrylonitrile-butadiene-styrene and polystyrene electrostatically.

Description of drawings

Fig. 1 is a schematic diagram showing the triboelectrification process of particles of the present invention, specifically, part (a) of Fig. 1 shows the phenomenon based on particles being charged by contacting with the surface of the charging device, (b) of Fig. 1 Partially shows the phenomenon that particles are charged by contact with each other.

Fig. 2 shows the vertical reciprocating charging device and charging buckets (polytetrafluoroethylene (PTFE) ), polyvinyl chloride (PVC), polypropylene (PP), high-density polyethylene (HDPE), polyethylene terephthalate (PET), high-impact polystyrene (HIPS), acrylonitrile-butylene Diagrams of diene-styrene (ABS), polyoxymethylene (POM), nylon (Nylon)), specifically, (a) of Figure 2 is a vertical reciprocating charging device, and (b) of Figure 2 is a charging device Bucket, Fig. 2 (c) is a Faraday cage (Faradaycage) for measuring charge polarity and charged quantity.

Fig. 3 is a schematic process diagram of the present invention.

Fig. 4 is a graph showing experimental results of charging characteristics of the present invention.

Fig. 5 is a graph confirming the screening efficiency of each charged substance of the present invention.

Fig. 6 is a chart for observing the influence of the voltage intensity of the electrode of the present invention on the quality and recovery screening efficiency of acrylonitrile-butadiene-styrene and polystyrene mixed plastics.

Fig. 7 is a graph showing the influence of the position of the separation zone on the screening efficiency for observation of the present invention.

Fig. 8 is a graph showing the effect of charging time on screening efficiency for observing the present invention.

FIG. 9 is a graph showing screening efficiency based on the ratio of mixed waste plastics of the present invention.

Fig. 10 is a graph showing the influence of the relative humidity of the present invention on the screening efficiency in material separation of mixed waste plastics.

Fig. 11 is a sectional view of a benchscale triboelectric charging type electrostatic screening device used in the present invention.

detailed description

Hereinafter, a preferred embodiment of the triboelectric electrostatic screening method for separating acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials according to the present invention will be described in detail with reference to the accompanying drawings.

The triboelectric electrostatic screening method for material separation of waste plastics mixed with acrylonitrile-butadiene-styrene and polystyrene according to the present invention is to make the different particles contact each other or make the particles and the charged particles A method of electrostatically separating acrylonitrile-butadiene-styrene and polystyrene by contacting the surfaces of the device to charge the particles with different polarities.

Fig. 1 is a schematic diagram showing the triboelectrification process of particles, specifically, part (a) of Fig. 1 shows the phenomenon based on particles being charged by being in contact with the surface of the charging device, and part (b) of Fig. 1 shows A phenomenon in which particles come into contact with each other and become charged.

As shown in Figure 1, in the present invention, if different particles collide and rub against each other or the surface of the particle and the charged device collides and rubs, then by virtue of the difference in work function, the electrons will be charged to the charge of the two substances. The meter energy levels gradually move in the same direction. If different particles are in contact with each other or after the particles are in contact with the surface of the charged device, the particles are separated from the surface again, and there will be an excess or shortage of electrons, so that the particles are negatively charged (-) or positively charged (+ ).

As mentioned above, if charged mixed particles with opposite polarities are passed through a high-voltage electric field, the positively charged (+) particles will move toward the negatively charged (-), and conversely, the negatively charged (-) particles will move toward Positively charged (+) machines move and separate from each other.

Hereinafter, the separated samples and experimental methods will be described in detail.

1) Samples and experimental methods

The sample used in the present invention is the plastic of waste electrical appliances purchased from Sejong Co., Ltd., which is a waste plastic made of mixed acrylonitrile-butadiene-styrene and polystyrene materials that are piled up in the field, placed or incinerated and landfilled. . Acrylonitrile-butadiene-styrene and polystyrene are the six major general-purpose plastics. Based on 2012, the production and demand of acrylonitrile-butadiene-styrene are about 1.45 million tons and 330,000 tons, respectively. The production and demand of polystyrene are about 640,000 tons and 200,000 tons respectively, that is, compared with polystyrene, the production of acrylonitrile-butadiene-styrene reaches about 2.3 times, the demand for acrylonitrile-butadiene-styrene reaches about 1.6 times the demand for polystyrene. Moreover, compared with other synthetic resins, the price of acrylonitrile-butadiene-styrene-polystyrene is about 300-500USD/ton higher. Based on 2012, the price of acrylonitrile-butadiene-styrene The price of polystyrene is 1891USD/ton, and the price of polystyrene is 1686USD/ton. Therefore, compared with the price of polystyrene, the price of acrylonitrile-butadiene-styrene is about 200USD/ton higher. Acrylonitrile-butadiene-styrene and polystyrene have excellent moldability, impact resistance, chemical resistance, heat resistance, mechanical strength and electrical insulation, high resin strength, thermal stability, adhesion property, paintability, etc. Therefore, the above-mentioned acrylonitrile-butadiene-styrene and polystyrene are used in office equipment, automobile parts, electronic equipment parts, etc. Among them, acrylonitrile-butadiene-styrene is widely used in automobile parts, electronic equipment parts, etc., and the production volume of acrylonitrile-butadiene-styrene is rapidly increasing not only in Korea but also in the world.

Fig. 2 of the present invention shows the vertical reciprocating charging device and the charging barrel (polytetrafluoroethylene) of each material used in order to study the charging sequence and charging characteristics of acrylonitrile-butadiene-styrene and polystyrene of waste plastics , polyvinyl chloride, polypropylene, high-density polyethylene, polyethylene terephthalate, high-impact polystyrene, acrylonitrile-butadiene-styrene, polyoxymethylene, nylon). (Because the above-mentioned charged bucket is a technical structure disclosed in Korean Patent No. 10-2008-0078125, its detailed description will be omitted.) In order to screen charged substances, first, acrylonitrile-butadiene- Styrene and polystyrene are respectively crushed into 6 mm or less by means of a cutting mill, and the particle size of acrylonitrile-butadiene-styrene and polystyrene is 1-6 mm by means of a sieve (1 mm).

The samples with adjusted particle size are put into various charged barrels, and the samples are rubbed and collided with each other by means of a vertical reciprocating charging device, and then the charge polarity and charge amount are measured by the Faraday cage in part (c) of Figure 2. And, based on this, a charged substance to be used for triboelectric electrostatic screening for material separation of mixed waste plastics of acrylonitrile-butadiene-styrene and polystyrene was selected.

Fig. 3 shows the experimental procedure figure of the present invention, at first, with the aid of cutting crusher and sieve, after the acrylonitrile-butadiene-styrene and polystyrene waste plastics crushing as target sample, its particle size is adjusted to 1 ~6mm in size, then mixed in a weight ratio of 1:1. The sample with adjusted particle size is put into the charging bucket made of acrylonitrile-butadiene-styrene, and with the help of a vertical reciprocating charging device, the sample is charged through friction and collision, and then the charged substance with the opposite polarity is charged to a high voltage. The electric field moves and separates. In addition, the optimal screening conditions and separation efficiency were confirmed by changing the experimental conditions such as the voltage intensity of the electrode, the position of the separation zone, and humidity.

2) Experimental results

1. Charging characteristics

For the material separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastics, a charge characteristic study for screening charged substances that can charge samples with opposite polarities was performed. Charge barrels of materials with different work functions and charging sequences (polytetrafluoroethylene, polyvinyl chloride, polypropylene, high-density polyethylene, polyethylene terephthalate, high-impact polyethylene Styrene, acrylonitrile-butadiene-styrene, polyoxymethylene, and nylon) are put into a sample in a single state, and the sample is charged by a vertical reciprocating charging device, and then the polarity and charge amount of the charge are measured by a Faraday cage. The experiment was carried out by setting the relative humidity as the experimental variable to 40% or less, the temperature to a normal temperature of 25° C., the rotational speed to 270 rpm, and the residence time to 2 minutes.

Fig. 4 shows the experimental results of charging characteristics. Because the work function values of acrylonitrile-butadiene-styrene and polystyrene as the target samples are smaller than the work function values of charged substances polytetrafluoroethylene, polyvinyl chloride, polypropylene, and high-density polyethylene, it has a positive The charge is negatively charged because the work function values of acrylonitrile-butadiene-styrene and polystyrene as the target samples are greater than those of polyoxymethylene and nylon. Conversely, in the case of polyethylene terephthalate, high-impact polystyrene, and acrylonitrile-butadiene-styrene, it is known that acrylonitrile-butadiene-styrene and polystyrene can have opposite polar charge. At this time, acrylonitrile-butadiene-styrene and polystyrene, which are the same material as the target sample, cause the target sample to be charged with opposite polarity as follows, even if the target sample is different from acrylonitrile-butadiene-styrene and polystyrene. The material of vinyl is the same, but the work function of the two is different due to the difference in the chemical composition of the internal structure of the plastic, additives, etc. Therefore, it was confirmed that the materials of acrylonitrile-butadiene-styrene, high-impact polystyrene, and polyethylene terephthalate can make the mixture of acrylonitrile-butadiene-styrene and poly Styrene waste plastics are oppositely charged.

Therefore, in the present invention, the screening efficiency of the charged substance was confirmed in order to select the optimal charged substance, and the results are shown in FIG. 5 . The above-mentioned charged substances use polyethylene terephthalate, high-impact polystyrene, and acrylonitrile-butadiene, which can make acrylonitrile-butadiene-styrene and polystyrene mixed waste plastics charge opposite polarity. ethylene-styrene, and polytetrafluoroethylene, high Density polyethylene, polypropylene. Figure 5 shows the quality and recovery rate of charged species-based acrylonitrile-butadiene-styrene using mixed waste plastics at a 1:1 ratio of acrylonitrile-butadiene-styrene and polystyrene. In the case of polytetrafluoroethylene, high-density polyethylene and polypropylene with the same polar charge, although the recovery rate is high, the quality is less than 60%, when considering that the mixing ratio of mixed waste plastics is 1:1 , it can be seen that almost no screening occurs. In contrast, in the case of polyethylene terephthalate, high-impact polystyrene and acrylonitrile-butadiene-styrene, recoveries of more than 90% and qualities of more than 80% were observed, where , In the study of charging characteristics, in the case of acrylonitrile-butadiene-styrene with obvious difference in charging amount, the quality and recovery rate were 99.5% and 92.5%, respectively, thus showing the highest screening efficiency. Therefore, in the present invention, acrylonitrile-butadiene-styrene was selected as a charged species and separation characteristic studies were performed.

2. The influence of voltage intensity

Figure 6 shows the effect of the voltage intensity of the electrode on propylene when the voltage intensity of the electrode is changed from 5kV to 25kV when the charging time is 30 seconds, the position of the separation band moves 2cm to the positive electrode direction (positive electrode) and the relative humidity is 30%. A plot of the effect of screening efficiency on the quality and recovery of nitrile-butadiene-styrene and polystyrene blended plastics. The higher the voltage strength, the higher the quality and recovery of acrylonitrile-butadiene-styrene, and it exhibits high screening efficiency. In the case of a lower voltage intensity of 5kV, the quality and recovery rate reached the lowest at 92.5% and 69.3% respectively, but the more the voltage intensity increased, the quality and recovery rate also increased. In the case of a voltage intensity of 20kV , the quality and recovery rate rose to 99.5% and 92.5%, respectively. When the voltage intensity reaches the highest voltage of 25kV in the present invention, the quality and recovery rate show the highest at 99.9% and 93.75%, respectively, but compared with the case of the voltage intensity of 20kV, there is not much difference, and similar screening efficiency. Therefore, when energy efficiency and screening efficiency are considered, it can be seen that acrylonitrile-butadiene can be efficiently recovered from waste plastics mixed with acrylonitrile-butadiene-styrene and polystyrene at a voltage intensity of 20 kV - Styrene.

As mentioned above, the greater the voltage intensity of the electrode, the reason why the screening efficiency also increases is as follows, as shown in the graph in Figure 6, the unit of charge amount of charged particles is nC/g, so the charge amount is extremely small, thus, In order to improve the separation efficiency of particles, higher electric power is required.

3. The influence of the position of the separation zone

The charged amount of the sample is affected by factors such as the work function value of the particles, temperature and charging time. As a result, each charged particle has a different amount of charge, and therefore, when the particles are separated in the electric field, the speed and distance at which the particles move toward the electrode are different. Therefore, proper conditions exhibiting higher screening efficiency can be obtained by shifting the position of the separation zone within the electric field.

In Figure 7, in order to observe the influence of the position of the separation zone on the screening efficiency, the voltage intensity is set to 20kV, the relative humidity is set to 30%, the charging time is set to 30 seconds, and the separation zone The position is centered on the landing port and moved 2 cm each time in the direction of the positive electrode and the direction of the negative electrode for a total of 6 cm. The experiment was carried out under the above conditions. As the position of the separation band moves from the positive pole to the negative pole of the electric field, it can be seen that the quality of acrylonitrile-butadiene-styrene is 99.9% at the position moving 6 cm towards the negative pole direction, and the quality of propylene is 99.9% at the position moving 2 cm and 6 cm towards the positive pole direction. The quality of nitrile-butadiene-styrene is respectively 99.5% and 98.2%, so there is not much difference, but the recoveries at the above-mentioned positions have reached 76.2%, 92.5% and 98.2% respectively, thus it can be known that the recoveries Increase.

The reason for these results is as follows. The recovered amounts of acrylonitrile-butadiene-styrene and polystyrene differ depending on the difference in charge amount of the particles and the position of the separation zone. In the case of polystyrene, which has a relatively high charging efficiency, the recovery of polystyrene is hardly affected by the change in the position of the separation band, but in the case of acrylonitrile-butadiene-styrene, the position of the separation band is farther from the positive electrode. Moving toward the negative electrode, the recovery region for positively charged acrylonitrile-butadiene-styrene widens, thereby increasing the recovery rate. Therefore, when considering the quality and recovery rate, it is most effective to move the 2cm position in the direction of the positive electrode. At this time, the quality and recovery rate are 99.5% and 92.5%, respectively.

Fourth, the impact of charging time

In Figure 8, in order to observe the impact of charging time on the screening efficiency, the voltage intensity is set to 20kV, the relative humidity is set to 30%, the position of the separation zone is set to move 2cm to the positive direction, and Experiments were performed with the charging time increased from 10 seconds to 60 seconds. As a result of the experiment, it can be seen that the quality and recovery rate of acrylonitrile-butadiene-styrene increase when the charging time is increased to 30 seconds, but after that, if the charging time becomes longer, the screening efficiency hardly changes, thus, it can be seen that The critical charging time has been reached.

As described above, the longer the charging time is, the reason why the screening efficiency increases is as follows, the longer the charging time is, the frequency of friction and collision between particles in the charged substance increases or the frequency of friction and collision between the charged substance and particles increases, and Effective charging is achieved, and thus the charging amount increases. On the contrary, when the charging time is 30 seconds or more, the screening efficiency does not change much, because the charging time of 30 seconds is a critical point for providing sufficient charge for screening the target sample. Therefore, in this study, the separation experiment was performed with the charging time of 30 seconds as the optimal experimental condition, at this time, the quality and recovery of acrylonitrile-butadiene-styrene were 99.5% and 92.5%, respectively.

5. The influence of mixing ratio

The samples used in the experiment of the present invention are waste plastics made of polystyrene and acrylonitrile-butadiene-styrene that are recovered from waste electrical appliances according to their materials. In order to observe the mixing ratio that presents the best screening efficiency, the propylene Experiments were performed by changing the mixing ratios of nitrile-butadiene-styrene and polystyrene to 1:9, 3:7, 5:5, and 7:3, respectively. The voltage strength as the experimental variable was set to 20 kV, the relative humidity was set to 30%, the position of the separation zone was set to 2 cm in the positive direction, and the charging time was set to 30 seconds.

Fig. 9 shows the screening efficiency of the ratio of mixed waste plastics, and it can be seen that as the amount of acrylonitrile-butadiene-styrene increases, the recovery rate decreases, but the quality increases. When the ratio of acrylonitrile-butadiene-styrene and polystyrene is 1:9, the quality and recovery rate are 95.4% and 94.8%, respectively, but after adding acrylonitrile-butadiene-styrene, the acrylonitrile - When the ratio of butadiene-styrene and polystyrene is 5:5, the quality and recovery rate are 99.5%, 92.5%, respectively, and when the ratio is 7:3, the quality and recovery rate are 99.4%, 82.8%, respectively. %, thus the quality will increase, but the recovery rate will decrease.

As mentioned above, the more the amount of acrylonitrile-butadiene-styrene increases, the reason why the quality becomes larger is as follows. Friction and collision between relatively large amounts of polystyrene occur, so it is difficult to charge mixed waste plastics, but the greater the amount of acrylonitrile-butadiene-styrene, the greater the chance of friction and collision between target samples. will increase, thereby effectively realizing the charging of acrylonitrile-butadiene-styrene. On the contrary, in terms of recovery rate, the more the amount of acrylonitrile-butadiene-styrene increases, the more the product tends to decrease. As mentioned above, if this is because the amount of acrylonitrile-butadiene-styrene increases, then The friction and collision between acrylonitrile-butadiene-styrene mainly occur, thereby reducing the charging efficiency. If the charging efficiency is reduced, the uncharged or very little charged particles cannot move to the recovery area of acrylonitrile-butadiene-styrene, so they are discharged to the recovery area of polystyrene, thereby reducing the acrylonitrile-butadiene-styrene Styrene recovery.

Therefore, in mixed waste plastics, when the quality and recovery rate of acrylonitrile-butadiene-styrene are considered, the quality and recovery rate of 5:5 acrylonitrile-butadiene-styrene can reach 99.5% and 92.5%, respectively. The highest screening efficiency was confirmed at the mixing ratio of styrene and polystyrene.

6. The influence of relative humidity

Figure 10 shows the effect of relative humidity on screening efficiency in material separation of mixed waste plastics. Under the condition that the supply voltage intensity is 20kV, the position of the separation zone is 2cm to the positive direction, and the charging time is 30 seconds, the relative humidity is changed from 20% to 70% in the mixed waste plastics. Screening efficiency for recovery of acrylonitrile-butadiene-styrene. It can be seen from the experimental results that when the relative humidity reaches 40%, the quality and recovery rate of acrylonitrile-butadiene-styrene are not affected, and if the relative humidity is greater than 40%, the acrylonitrile-butadiene-styrene will be greatly reduced. Butadiene-styrene quality and recovery.

The quality and recovery of acrylonitrile-butadiene-styrene were the highest at 99.9% and 92.9%, respectively, when the relative humidity was the lowest at 20%, and even when the relative humidity was increased to 40%, the quality and recovery were 98.7% and 90.1%, so there is not much difference. Moreover, it can be seen that if the relative humidity is greater than 40%, the screening efficiency will be greatly reduced, and when the relative humidity is the highest 70%, the quality and recovery rate will drop to 70.6% and 48.6% respectively.

Therefore, it can be seen that in order to improve the screening efficiency, it is necessary to maintain a relative humidity lower than 40%. In the experiment of the present invention, the material separation experiment was carried out under the optimum condition of 30% relative humidity. At this time, the acrylonitrile-butadiene - The quality and recovery of styrene were 99.5% and 92.5%, respectively. As mentioned above, the reason why relative humidity affects the material separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastics is as follows. Surface polarization, even if the particles are charged, will reduce the charge by way of discharge.

Fig. 11 is a cross-sectional view of a laboratory scale triboelectric electrostatic screening device used in the present invention. As shown in Figure 11, the frictional electrification type electrostatic screening device 200 includes: an inlet 210 for supplying mixed particles of acrylonitrile-butadiene-styrene and polystyrene to the inside of the triboelectric electrification type electrostatic screening device 200; The compressor 240 injects air in order to move the mixed particles injected from the injection port 210 to the pipeline and the cyclone charging device; the pipeline 250 and the cyclone charging device 230 are used to negatively charge (-) the injected polystyrene particles and make them The acrylonitrile-butadiene-styrene particles are positively charged (+); the negative plate 250 and the positive plate 260 are used to move and separate the acrylonitrile-butadiene-styrene and polystyrene according to the polarity; the separation band 270, used to separate the separated acrylonitrile-butadiene-styrene and polystyrene particles, the position of the above-mentioned separation belt 270 can be adjusted; the power supply part 280 is used to supply the negative electrode plate 250 and the positive electrode plate 260 supplying electric power; and a drop port 255 for dropping charged polystyrene particles and acrylonitrile-butadiene-styrene particles.

The separation zone 270 includes: a first recovery zone 272 for trapping positively charged (+) acrylonitrile-butadiene-styrene particles; a second recovery zone 276 for capturing negatively charged (-) polystyrene particles; and a third recovery zone 274, used to capture the mixed particles of unseparated acrylonitrile-butadiene-styrene particles and polystyrene particles. At this time, the above-mentioned separation belt 270 can be in the shape of a plate, and the above-mentioned separation belt 270 and the above-mentioned recovery belts 272, 274, 276 are formed into one body. Triangular or trapezoidal so that Acrylonitrile-Butadiene-Styrene particles and Polystyrene particles can be easily captured from each recovery zone. At this time, the above-mentioned separation belt 270 is centered on the apex of the triangle formed by the two plates extending from the above-mentioned recovery belt, inclined to the negative electrode plate and the positive electrode plate to form a trapezoid. As mentioned above, in order to obtain high-quality acrylonitrile-butylene Diene-styrene, the plate in the negative direction extending from the recovery belt can move 6cm to the negative direction, in order to obtain high-quality and high recovery of acrylonitrile-butadiene-styrene, the plate in the positive direction extending from the recovery belt It can move 2cm to 6cm towards the positive pole.

And, the frictional electrification type electrostatic screening device 200 used in the present invention can also include an air drying unit 290, and the above-mentioned air drying unit 290 is used to remove moisture in the air supplied from the air compressor 240 to the pipeline 220 and the cyclone charging device 230, The above-mentioned frictional electrification type electrostatic screening device 200 may also include an air flow meter 295, the above-mentioned air flow meter 295 is formed in a part of the connecting pipe connecting the air compressor 240 and the injection port 210, and the above-mentioned air flow meter 295 can be used to adjust the flow rate from the air compressor. 240 the amount of air supplied.

The present invention of the above-mentioned structure has been described with reference to the limited embodiments, but the present invention is not limited thereto, those of ordinary skill in the technical field of the present invention are equivalent to the technical thought of the present invention and the scope of protection of the invention described below Various modifications and variations can be seen within the technical scope.

Claims (as amended under Article 19 of the Treaty)

Received by the International Bureau on April 22, 2015 (22.04.2015)

1. A triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials, characterized in that, it is used to use the triboelectric electrostatic screening method to mix propylene Acrylonitrile-butadiene-styrene material is recovered from waste plastics of nitrile-butadiene-styrene and polystyrene. The charged material separated is composed of polyethylene terephthalate, high-impact polystyrene and A composition of acrylonitrile-butadiene-styrene, which uses the charged substances separated from the above-mentioned materials to charge the above-mentioned acrylonitrile-butadiene-styrene and polystyrene with opposite polarities.

2. the triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic material according to claim 1, is characterized in that, in the screening process of above-mentioned charged substance, The voltage strength is 15kV ~ 25kV.

3. the frictional charging type electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic materials according to claim 1, it is characterized in that, for carrying out above-mentioned frictional charging type electrostatic screening method In the screening device, the separation belt is located at the lower part of the discharge port where the charged waste plastics fall. In order to recover high-quality acrylonitrile-butadiene-styrene, the separation belt moves 6cm from the discharge port to the direction of the negative electrode. In the case of quality and recovery, the separation zone moves 2cm to 6cm from the center of the falling port to the positive electrode.

4. the triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic material according to claim 1, is characterized in that, in the screening process of above-mentioned charged substance, The charging time is 20-40 seconds.

5. the triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic material according to claim 1, is characterized in that, in the screening process of above-mentioned charged substance, The relative humidity is 20% to 40%.

6. the triboelectric electrostatic screening method for the separation of acrylonitrile-butadiene-styrene and polystyrene mixed waste plastic material according to claim 1, is characterized in that, the more above-mentioned acrylonitrile-butadiene is increased - The amount of styrene, the lower the recovery rate, but the higher the quality.

Statement or declaration (as amended under Article 19 of the Treaty)

PCT Division of China Patent Office:

The following is based on

(√) PCT Article 19

() PCT Article 28/PCT Article 41

() Explanation of the amendments made to the annexes of the international preliminary examination report, in which

1. Replaced by items 1-6 of the amended claims

Items 1-6 of the original claim;

2. Replace with revised instruction manual page _____

Page _____ of the original manual;

3. Replaced with the revised page of the attached figure

Original attached page.

4. Replace with the revised summary page

Original abstract p.

5. increase

Please refer to the submitted revised manuscript for specific revisions.

Beijing Guofan Intellectual Property Agency (General Partnership)

2016/4/13

Instructions under Article 19(1)

The claims in the above international application are amended as follows.

1. Amended claims

Claim 1 is further defined, and claim 3 is amended.

2. Modify the content

It is clearly pointed out that the above-mentioned acrylonitrile-butadiene-styrene and polystyrene are respectively charged with opposite polarities by using the charged substance separated from the above-mentioned material described in claim 1 of the present invention. The above "2cm to 6cm" is changed to "2cm to 6cm".

3. The relationship between the amendment of the claims and the description and drawings

The above-mentioned amendments to claim 1 and claim 3 are defined based on the content of the invention of the present invention, and thus do not have any influence on the specification and drawings.

Claims (6)

1. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS), it is characterized in that, for using triboelectric electrostatic screening technique to be made up of from being mixed with the charge species that acrylonitrile-butadiene-styrene (ABS) separates with the material of Propylene recovery nitrile-butadiene-styrene the waste plastics of polystyrene the one in polyethylene terephthalate, high impact polystyrene and alkene nitrile-butadiene-styrene.

2. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS) according to claim 1, it is characterised in that in the screening process of above-mentioned charge species, voltage strength is 15kV��25kV.

3. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS) according to claim 1, it is characterized in that, for carrying out in the device that above-mentioned triboelectric electrostatic screens, separating belt is positioned at the bottom of the landing mouth of charged waste plastics landing, in order to reclaim the acrylonitrile-butadiene-styrene (ABS) of high-quality, separating belt moves 6cm to negative pole direction centered by the mouth that lands, when for the purpose of high-quality and the response rate, separating belt moves 2cm to 6cm to positive extreme direction centered by the mouth that lands.

4. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS) according to claim 1, it is characterised in that in the screening process of above-mentioned charge species, electrification time is 20��40 seconds.

5. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS) according to claim 1, it is characterised in that in the screening process of above-mentioned charge species, relative humidity is 20%��40%.

6. the triboelectric electrostatic screening technique separated with polystyrene mixed waste plastic material for acrylonitrile-butadiene-styrene (ABS) according to claim 1, it is characterized in that, more increase the amount of aforesaid propylene nitrile-butadiene-styrene, can more reduce the response rate, but quality can be more high.