CZ399597A3 - Recycling process - Google Patents

Abstract

This new recycling process treats wastes, plastic mixtures and plastic composites. The mixed plastics and composites are separated by type, leaving other residual materials. The sorted plastic or plastic mixture undergoes wet treatment to clean the surfaces. An extractant removes soluble components of the plastics. Preferably the plastic mixture comprises polypropylene, polyethylene terephthalate, polyvinyl chloride, polystyrene, low density polyethylene, high density polyethylene and polyurethane. The composites include metals and/or thermally-useful residues and one or more of the plastics above. Composites are separated before the wet treatment, into plastic components, residual materials and if appropriate, metallic components. The sorted plastics are dried after wet treatment. The plastic or plastic mixture is size reduced before wet treatment. Water is used in wet treatment; extraction employs a halogen- and aromatic-free substance, especially ethyl acetate. Any extractant residues left adhering to the plastic, are removed by water or heating. The plastic is extruded and granulated after extraction. Composite materials comprise packing, electronic scrap, aluminium composites, or scrap cable. Plastic mixture comprises hollow ware, sheets and other plastic objects.

Description

The invention relates to a recycling process for the treatment of wastes, plastic mixtures and plastic layered materials.

BACKGROUND OF THE INVENTION

The German Waste Act provides for the management of waste recovery, the so-called waste recovery order. According to him, the recovery of waste, ie the recovery of substances or energy from waste, then takes precedence over other disposal operations if:

- the recovery is technically feasible,

the costs incurred are not too high in comparison with other methods, and

- it is accessible získané for the substances obtained or for the energy obtained

Waste recovery enables the multiple reuse of substances while saving primary raw materials or saving primary energy carriers. Special attention is paid to the recycling of plastics in waste recovery. In the case where the plastic waste is provided sorted, the recycling presents little problems, since the thermoplastic plastic materials in this case are easy to process by extrusion and granulation. The recovery of plastic waste is problematic if it was provided as a mixture of plastics or laminated materials. Typical plastic mixtures are found, for example, in household wastes that have been sorted according to the Dualen System Deutschland (DSD). The plastic fractions contain various materials such as ~ ΊΟ · · 0

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0 0 0 • 0, 0 0 0 0 polystyrene, polypropylene, polyethylene and their germany are not usable without further processing.

Since DSM waste plastics mixtures are not yet divisible to the desired extent to the individual components, methods have been developed in recent years to improve the thermal recovery of such wastes. However, such facilities are disadvantageous both from an ecological and an economic point of view, since valuable raw materials are lost and a greater part of the internal energy remains unused.

In recent years, great progress has been made in the art of recycling after 1 yo 1 e. for packaging. In particular, the processing of the film and hollow fractions could be improved in order to prepare practically pure, high-grade plastic materials as an output product for use.

The problem with the processing of plastic waste, in particular from species-impure plastic waste, is that impurities adhere to the plastic waste. These impurities can, for example, come from tanks or from harmful substances that diffuse from the outside. Further, such packages are often printed so that the inks must also be wiped off.

Wet treatment systems are generally used to remove such impurities in which the plastic waste is treated with water. Multi-stage, water-based cleaning systems are used for processing. The recyclate is very unpleasant after this wet treatment. odor and undefined color and therefore can only be used to a limited extent. I.e. the field of application of such recycled materials is limited to materials that are subject to minimum quality requirements - such as waste bags, park benches, containers, clothes bags, etc. In such cases, often new materials and other fillers to meet low quality requirements.

As an alternative to wet treatment, extraction methods have been developed in which purification is performed in place of water with FCKW- and aromatics-free extraction agents. Such a method is known, for example, under the name NOREC. The use of this method is limited to thin-walled polyethylene and polypropylene containers and thin-walled plastic containers of polyolefins.

The advantages of the NOREC process over the existing wet treatment with water are considerably lower energy requirements and improved cleaning efficiency.

The abovementioned methods of purification, however, are used in the first plastic components provided practically species-clear. To date, no recycling process is known by which multi-plastic wastes could be treated to obtain a recycled material which practically corresponds to a new product in terms of substance properties.

SUMMARY OF THE INVENTION It is therefore an object of the present invention to provide a recycling process which makes it possible, at a minimum of technical costs, to treat waste which comprises several types of plastics easily.

SUMMARY OF THE INVENTION

This object is solved by the features of claim 1.

Measures in which the plastic wastes first pass through the wet processing and mechanical separation steps and the wet and mechanically separated fractions are then treated in the extractor with an extraction agent to separate the plastic mixtures and the laminates into species-pure plastics which practically no more impurities. By successive wet processing and extraction arrangements, the technical cost of carrying out the extraction and hence the amount of extracting agent can be minimized, so that all environmental requirements are met.

The process according to the invention is particularly advantageously applicable to wastes containing plastics of the PP, PET, PVC,

PS, JLDPE, HDPE and PUR, F and A and / or pulse --------------- useful residues.

If the wastes contain layered materials, these are preferably separated into plastic components and other materials prior to wet processing. For such separation, it is advantageous to use an ultrasonic separation method in which the laminates exhibit a high acceleration.

The wet treatment may be carried out before the mechanical separation of the plastic mixture. However, it is also possible for the plastic mixture to be first separated and then subjected to a wet treatment.

In wet processing, it is particularly effective when the plastic mixtures or the pre-separated species-pure plastic fraction is first ground prior to wet processing in order to provide the maximum specific surface area for use.

The wet treatment is preferably carried out with water which has been brought to a temperature between 60-95 ° C, preferably 90 ° C.

Extraction is carried out using FCKW- and aromatic-free extracting agents, for example ethyl acetate.

The extraction agent adhered to the species-pure plastic after the extraction step is separated by water or heat treatment and recycled to the extraction process.

The plastic fractions purified by the wet process and the extraction step are preferably homogenized by extrusion and granulation and brought to a state of transport and sale.

If the waste also contains a species-pure plastic fraction, it can be recycled directly to the extraction step after grinding after wet-grinding.

Particularly preferred embodiments of the invention are at the heart of the other dependent claims.

Preferred embodiments of the invention are explained in more detail below with reference to the schematic drawings.

Description of the figures in the attached drawings

Figure 1 shows the flow diagram of the recycling process of the invention and Figure 2 the flow diagram of the mechanical separation used internally in the recycling process of the invention.

As previously described, plastics in industrial or household wastes such as packaging foils, hollow bodies (bottles, containers, etc.) and laminates of plastics and other materials (metal, mixtures, etc.), hereinafter referred to as sandwich, are not provided clean and generically clean to waste treatment facilities. Also, the wastes provided by the Dualen System Deutschland (DSD) are usually neither pure nor generically pure, which requires considerable processing costs for the valuable substances.

By the method according to the invention, said laminates (packaging, electronic waste, cable residues, etc.), hollow body mixtures, foil mixtures, plastics mixtures such as generically pure foils, generically pure hollow bodies and generically pure plastics waste from trades can be processed and industry.

___ Similarly, it is easier to process type-clean foils, hollow bodies and plastics waste that are separated by type of plastic (eg polypropylene (PP), polyethylene glycol terephthalate (PET), polyvinyl chloride (PVC), polystyrene (PS)) , polyethylene of lower density (LDPE), polyethylene of higher density (4LDDE -) - and 1 yurethane (PUR) and which they are introduced into a comminution stage in which the plastics are brought to a predetermined size. After the comminution step, which can be carried out through a grinder or a scissor mill, these plastics are generically pure as foil cuttings or pieces of plastic with a maximum diameter of about 3 cm. This comminuted species-pure fraction is stored in intermediate storage.

For example, the folding may be carried out in a plastic silo.

- The components of the plastic waste provided, which are not generically pure, ie sandwiches, mixtures of hollow bodies, foils and mixtures of plastics are first mechanically separated and separated (step 1) as shown in figure 1, subjected to after or before wet processing (step 2) and in the attached purification step, dissolve the soluble components with a suitable extraction agent (step 3).

Mechanical / physical separation can be accomplished in many ways. For example, Figure 1 shows the mechanical separation and separation by manually sorting the supplied sandwich and plastic mixture. For this purpose, the supplied material is fed onto a conveyor belt and graded manually to achieve coarse screening for organic components, thermally recovered materials, thermoplastic mixtures, sandwiches and metal.

For example, the organic materials can be further processed in a bioreactor to form a methane piano, which is then usable for energy recovery.

______________ Industrial grade materials such as metals and thermally usable products are separated and lead to market appreciation. Waste residuals for which no market is accessible and which are also not biodegradable are further processed, in principle landfills or thermal bases are considered η í ___'—------- After the first pre-screening, the remaining stream The waste stream is introduced into an automated mechanical distribution in which the material stream is divided into its individual components.

Figure 2 provides an example for such a mechanical / physical distribution. Pre-sorted plastic mixtures which, depending on the type of waste, may still be mixed with glass, wood, cardboard, organic materials and metals (Al, Cu, Cr-Ni, Pb, steel 1, etc.) which have not been sorted out and / or by a scissor mill (preferably) and brought to a predetermined size. As with the pure species provided, this predetermined size may be limited, for example, to a maximum diameter of 3 cm.

99

Said wire shears and scissors or mills serve to grind soft, elastic and viscous materials and have long been known in the art, so that a detailed description of the apparatus used can be omitted here for simplicity. The same also applies in principle to those devices which are used in the following process steps, so that only the essential features of the apparatus and tools used can be described here. After comminution, the fabric stream can be intercalated (Figure 2) or used directly in the next processing step.

Referring to Figure 2, the pre-sorted fabric stream is comminuted after grinding and, if necessary, crosslinking. It introduces magnetic separators through which magnetic components such as iron can be separated. For example, a magnetic drum separator can be used, in which the divided fabric stream is fed to a shaking trough in which the particles are evenly distributed.

The material stream is fed to a separator drum. The fixed electromagnets are applied only to a partial range of the drum.

No force of the electromagnets acts on the non-magnetizable particles and these are transported further. The magnetizable particles are removed from the electromagnets on the rotating cylinders. On the underside of the cylinder, the attractive force of the magnets does not act and the magnetizable substances fall under their own weight into the magazine or onto another conveyor belt. Of course, other magnetic separators can also be used, which can also advantageously operate continuously.

Especially when the divided fabric stream comprises layered materials, such as plastics mixtures, electronic scrap, cable debris, etc., in the mechanical distribution, a further method step is introduced in which the sandwiches are separated in order to separate the plastic components.

9 9 9 ···· laminated materials from other materials.

For example, comminuted substances of comparatively high acceleration can be used to distribute the sandwich, overcoming the adhesive forces, and in this way the laminate is separated into its starting components. Such a high particle acceleration can be achieved, for example, by ultrasonic separating devices called so-called accelerators - where the split fabric stream is ultrasonically treated. This ultrasonic treatment of the sandwiches separates both the plastic mixtures and the metal-coated sandwiches so that the thermoplastic plastic components can be mechanically processed in the next process step.

To separate other components (metals, thermosetting plastics, glass, wood, cardboard, organic materials, etc.) from thermoplastic components, the fabric stream is introduced into one or more sorting stages. The pre-screening can be carried out by means of sieves or by crushing the sieve. The sieve can be used for separating with a grain size of several micrometers (pm) up to 5 mm.

Separation sorting consists in resistance to air of different particle sizes in the air-stream.

For example, the separation can be carried out in a transverse separator, where the air flow is conducted across the fabric flow. Of course, it is also possible to use other types of separators, such as a zigzag-separator, or a separator with a high speed. —- = --- ------- ^ - = - - - = ™ === ^ === = = ™ -

Separators can suitably separate components with a specific weight that is substantially different from the specific weight of the plastic materials. Such materials are, for example, glass, wood, paper / paperboard, organic materials.

and the aforementioned metals. These substances are divided according to their specific weight and collected in containers. Since these materials are valuable substances, they can be used for further use.

Separation fails when materials with nearly the same densities are contained in the fabric stream. Such material vapors comprise, for example, PP, PET; PVC, PS; LDPE, HDPE; Al, PUR. I.e. By simple air separation, the fabric stream can only be divided into several subgroups (heavy fraction, light fraction) in which the aforementioned fabric vapors are contained. Separation In difficult fabric mixtures, many kinds of __________ "plastics are combined with a sieving stage" to which ________ may optionally be attached. In FIG. 2, the screening step is always shown at the end of the separating step _. __

By means of the screening step before or after the separation, it is relatively simple to remove the coarse substances (cardboard, etc.). The residue on the sieves can then be further separated by separation.

The separation into individual components must be carried out in combination with a further process step. This can be done, for example, in combination with fine screen sorting. The so-called fine sieve separating device can be used to separate the components of a single group, for example PP and PET, and then be fed generically into a corresponding container, for example silo.

Mechanical / physical separation can also be accomplished by separation from the aluminum contained in the aluminum-composite layer. material, from a plastic material of almost the same density, e.g. PUR, so that it is also feasible generically pure

TT • 9 te · 9 te · · · · · · · · · · · · · · · · · · · · · · · · · · · · · · separation from Al.

After passing through the sieving devices, which can possibly interact once more with the separators and accelerators, the species-pure components (PP, PET, PVC, PS, LDPE, HDPE, PUR and Al) are fed into the silos and stored.

The individual components of the equipment, ie Shredder, scissors, magnetic separator, ultrasonic equipment (accelerators), separators and sieving equipment are always designed as closed systems and operate at reduced pressure. To control the risk of dust explosion, hazardous areas are designed ________ as pressure-resistant or with pressure relief.

Metals which are removed after mechanical separation (aluminum, iron, etc.) are sold - as in pre-screening - and the unusable residues are stored in a landfill or recovered for thermal recovery.

In addition to the mechanical separation, the drop-off species-pure thermoplastics are subjected to a wet treatment. According to the flow diagram shown in FIG. 2, wet processing is carried out after mechanical separation into thermoplastic components.

However, the wet treatment can also be carried out before the mechanical separation step or between the sub-steps (comminution and separation) of the separation, so that the thermoplastic mixture undergoes the wet treatment before it is mechanically degraded. While this is done before the wet processing, laminates are separated in which sandwiches are divided into thermoplastics and other materials (metals and other residuals).

In this layer separation step, the ultrasonic separation (acceleration) described above is used to separate the plastics from other materials.

• · · · · · · · · · · · · · · · · · ·

As mentioned previously, the species-pure plastic components (mechanical separation according to Figure 2) or the thermoplastic composition obtained after sorting and separating the laminates are subjected to a wet treatment in which the surfaces of the fabric or the fabric mixture are cleaned.

The cleaning medium used here is preferably water, which is heated to a temperature between 60 and 95 ° C, preferably about 90 ° C.

This wet treatment removes dirt, putrefaction, organic constituents, residues (for containers, for example, the remainder of the product taken off) and possibly printing inks, on the surface. The wet treatment can be carried out in two stages with different itepl o t and m i d i n d a nd s w a t water pressure____________________

In the case where the plastics mixtures are pretreated, only the mechanical separation is shown at the end, as shown in Fig. 2. In this embodiment, however, the thermoplastic blend is preceded by a predetermined grain size prior to wet processing. oirťícu / scissor mills.

As is further evident from Figure 1, it is also possible to drain the wet, so that these plastics can be directly pulverized (scissor mill) stored if the layered substances are not contaminated, further processed without wet processing.

wt per

Also in the case of artificial processing step by step in silos can be

Externally processed, pure plastics can then be collected in intermediate storage facilities.

After mechanical separation (step 1) and wet treatment (step 2) of the thermoplastic plastics components, these are separated by species and passed to the next purification stage. • • • • • • • • • • • • • • • • • • • • • • • • • • • . In this, the soluble constituents of the plastic particles (plastic cuttings) are removed by means of FCKW- and aromatic-free extracting agents, for example ethyl acetate. In doing so, they can also be freed of the filled products (containers) from the inside and under ambient conditions from the outside of the diffused components, especially odorous substances. In addition, during the described pretreatment steps, the polymers degradable to waxy components that have been deposited in the polymer matrix can be removed by dissolution. In this way it is also possible to remove adhering mineral and greasy impurities as well as crosslinked inks. Further, the migration-capable substance is dissolved.

As already mentioned, the extraction process as such is already known as the NOREC method.

The extraction is carried out in a carousel extractor in which a multi-stage extraction is carried out. The tuscan carousel extractor is located in a fixed round trough with a slotted floor turnstile, which rotates slowly. This turnstile is subdivided into mutually separated cells into which the extraction material, i.e. the species-pure plastic, is filled. The extraction material rotates slowly with the turnstile further and is sprinkled with solvent during circulation. This leaks through the extraction material and flows through the slotted floor into the collecting basin. After the extraction material has rotated together with the turnstile and has been leached, it falls out of the hole through the opening in the solid crevice floor. ’- ==. '. In such a carousel arrangement, the turnstile cells are continuously filled with fresh extraction material and fall out continuously after the turnstile rotation. The extraction agent is also introduced continuously and leaves continuously with a load of 4 '

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4 4 _ 4 4

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4444 4 44 44 extract. The solvent is conducted in countercurrent to the circulating extraction material.

Through this extraction step, the impurities are dissolved and exited with the extraction agent (ethyl acetate).

The loaded extractant is then treated, for example by evaporating the latter for example by heating to a temperature above the boiling point of the extracting agent, thereby separating the heat from the residues. The condensed extractant can again be fed into the extraction process continuously and almost without loss.

The thermally separated residuals are then treated (landfill, thermal recovery). ..__ „____________._

The extractant adhering to the species-pure plastics is rinsed with water and then dried or heat removed by heating.

In the former case, the water / extractant waste mixture is again thermally distributed so that both pure water and the extractant can be recycled to the process.

Of course, other continuously operating types of extractors such as conveyor screw extractors or belt extractors can also be used instead of a carousel extractor.

In connection with the extraction stage, the limit of the storage of the species-pure plastic components can again be carried out.

In the next step, the species-clean, purified thermoplastics are extruded and then granulated to form

Homogenised and ready-to-use feedstocks.

As indicated in Figure 1, the obtained granulates are collected in granular silos after extrusion and then fed to the respective sales or transport units.

At the end of the processing, a high-grade recyclate is obtained which practically does not differ in terms of its substance properties from the corresponding new product. Thus, the recycle can be recycled to the product circulation without any restrictions.

The process according to the invention makes it possible for the first time to virtually any thermoplastic mixtures of household, industrial and commercial wastes to be treated, separated and introduced generically pure for further, high-value applications.

Claims (14)

1. A recycling process for the treatment of wastes containing plastic mixtures and plastic layered materials, by the steps of: - the mechanical separation of the plastic mixture and of the laminates into species-pure plastics and other residual substances, wet treatment of the species-pure plastics or blends, including surface cleaning materials; and extracting the soluble plastic components with an extraction solvent. Recycling method according to claim 1, characterized in that ---------- in that the plastic mixture also comprises plastics of the groups PP, PET, PVC, PS, LDPE, HDPE and PUR and laminated materials with metals and / or heat-recoverable residues as well as one or more more of said plastics. Recycling process according to claim 2, characterized in that the layered materials are separated into plastic components, residual substances and optionally metal components before wet processing. 4. _ree Yk] é _ACE according _to any one of the preceding claims, - · - - characterized in that the pure-grade plastics material is dried after wet processing. Recycling method according to any one of the preceding claims, characterized in that the plastics or 4-9 99 plastic mixtures are comminuted before wet processing. Recycling process according to any one of the preceding claims, characterized in that the wet treatment is carried out with water and extracted with FCKW- and aromatic-free extracting agents. Recycling process according to claim 6, characterized in that ethyl acetate is used as the extraction agent. 8. A method according to claim 7, characterized in that the extractant adhering to the plastic is separated from the plastic by water or by heating. Recycling process according to one of the preceding claims, characterized in that the plastics are extruded and granulated after the extraction step. Recycling method according to any one of the preceding claims, characterized in that the layered materials comprise packaging, electronic scrap, Al-layered materials or cable residues and the plastic mixtures comprise hollow bodies, foils and other plastic components. , Recycling method according to one of the preceding claims, characterized in that the mechanical separation step comprises ultrasonic separation, separation or sieving step. —---- ^: ..... _ Recycling process according to one of the preceding claims, characterized in that the wet treatment is carried out at a temperature of 60 to 95 ° C, preferably 90 ° C. 9 9 9 9 9 9 99 9 .9 9 9 9 9 9 9 • 9 9999 9 «99 Recycling process according to any one of the preceding claims, characterized in that the generically pure plastic fraction contained in the waste is comminuted and fed into the extraction without wet treatment. Recycling method according to one of the preceding claims, characterized in that the organic fraction contained in the waste is separated by mechanical separation.