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Title:
DEVICE AND METHOD FOR SEPARATION OF COMPONENTS OF COMPOSITE PACKAGING MATERIALS
Document Type and Number:
WIPO Patent Application WO/2016/209094
Kind Code:
A1
Abstract:
The invention provides separation method of composite packaging ingredients, containing a polymer film, aluminium and/or cellulose and including steps in which the waste is initially broken down, an extraction of the polymer fraction is performed using xylene or other organic solvents such as benzene, toluene, cumene, ethylbenzene, naphtha, chlorobenzene, dichlorobenzene, bromotoluene, followed by separation of insoluble ingredients by grinding them down in a mixer, the precipitate of aluminium and cellulose particles is transformed into a liquid suspension with density higher than cellulose density and lower than aluminium density which is next dosed into a separator, whilst polymer solutions are evaporated in order to regenerate the solvent, and the initial polymer ingredient of the processed waste is separated. The invention is also related to a device for separation of composite packaging ingredients, in which a tank (1) contains sections with groups of horizontal strings (2, 3) located above and below the level where suspension is introduced, fixed on frames and set up in groups with string distance of 10 to 30 mm, more preferably 15 mm to 20 mm.

Inventors:
GRZYBOWSKI, Piotr (ul. Wrocławska 13 lok.3, Warszawa, PL-01-493, PL)
Application Number:
PL2015/000100
Publication Date:
December 29, 2016
Filing Date:
June 29, 2015
Export Citation:
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Assignee:
23 RS CORAS SP. Z O.O. (ul. Poznańska 16 lok.4, Warszawa, PL-00-680, PL)
International Classes:
B29B17/02; B03B5/02; B03B5/28; B03B5/36; B03B5/44
Foreign References:
US5198471A1993-03-30
DE4033701A11992-04-23
US20070187299A12007-08-16
DE19825235A11999-12-09
DE4028999A11992-03-19
US5507393A1996-04-16
PL337131A12000-07-31
PL181919B12001-10-31
PL201423A11978-07-17
PL398044A12013-08-19
PL219475A11981-06-05
DE4028999A11992-03-19
US4168199A1979-09-18
CN101745518A2010-06-23
EP0568791A21993-11-10
CN101773923A2010-07-14
ES2087013A11996-07-01
Attorney, Agent or Firm:
KAMIŃSKI, Zbigniew (Kancelaria Patentowa, Al. Jerozolimskie 101/18, Warszawa, PL-02-011, PL)
Download PDF:
Claims:
Claims

1. A method for separation of components of composite packaging materials, comprising polymer film, aluminium and/or cellulose, wherein said method includes steps of dividing initially the waste packaging materials into 10 cm x 10 cm or smaller pieces, extracting the polymer fraction using xylene or other organic solvents such as benzene, toluene, cumene, ethylbenzene, naphthalene, chlorobenzene, dichlorobenzene, bromotoluene, then separating the insoluble ingredients by fragmenting them in an agitator, forming the slurry from the aluminium and cellulose particles, wherein said slurry have higher density than cellulose density and lower than aluminium density, dosing said slurry into a separator, while evaporating the polymer solutions to recover the solvent, and separating the initial polymer ingredient of the processed packaging waste.

2. The method according to claim 1 wherein said method comprises the step of filtering the insoluble particles of metallic aluminium and cellulose after extraction of polymer ingredients.

3. The method according to claim 1 or 2 wherein conducting the extraction process of waste polymer fraction at higher temperature, preferably at the boiling point of the solvent.

4. The method according to any of claims 1-3 wherein conducting the extraction process of waste polymer fraction at highter temperature and under elevated pressure, at a temperature higher than typical solvent boiling point.

5. The method according to any of claims 1-4 wherein conducting the process of polymer fraction extraction with a single or multiple solvent portions and performing the process periodically or continuously.

6. The method according to any of claims 1-5 wherein drying the precipitate of aluminium and cellulose particles is carried out before their separation and the method comprises the step of rinsing the precipitate using solvent alone to purify and remove residues of the polymer solution.

7. The method according to any of claims 1-6 wherein introducing the suspension of insoluble ingredients at half the depth of the separation tank.

8. The method according to any of claims 1-7 wherein introducing the suspension, after separation of insoluble ingredients, onto a system of horizontal strings fixed onto frames in groups, with a string distance of 10 to 30 mm, preferably 15 mm to 20 mm.

9. The method according to claim 8 wherein making the strings to vibrate with a frequency of 0.5 Hz to 5 Hz, more preferably of 1 Hz to 2 Hz with amplitude of 1 mm to 45 mm, preferably 10 to 15 mm, preferably in the horizontal plane.

10. The method according to claim 8 or 9 wherein making every second layer of strings in the given group to vibrate in the same phase and opposite to other layers in the same group.

1 1. A device for separation of components of composite packaging materials containing a polymer film, aluminium and/or cellulose, wherein a tank (1) contains sections with groups of horizontal strings (2, 3) located above and below the suspension introducing zone, wherein said strings are fixed to frames and set up in groups with string distance of 10 to 30 mm, more preferably 15 mm to 20 mm.

12. The device according to claim 11 wherein every group of strings (2, 3) contains 1 to 50 layers, preferably 5 to 30, more preferably 12 to 22 layers of strings.

13. The device according claim 1 1 or 12, wherein the strings vibrate (5) with a frequency of 0.5 Hz to 5 Hz, more preferably of 1 Hz to 2 Hz with amplitude of 1 mm to 45 mm, preferably 10 to 15 mm, preferably horizontally.

14. The device according to any of claims 1 1-13, wherein every second layer of strings in the given group vibrates in the same phase and opposite to other layers in the same group.

Description:
Device and method for separation of components of composite packaging materials

The present invention provides a method for separation of ingredients of composite packagings, including a polymer film, aluminium and/or cellulose and a device for separation of ingredients of composite packagings.

Polymer films are currently one of the most common packaging materials. Such films are made of various materials and have various thicknesses. Metal-coated films are a special type of packaging foils and foils designed for special use. They are coated with a thin layer of metal, usually in a process of vacuum metallisation, or are glued with/heat- welded with a metallic foil. Aluminium foil is the most used material of this type. Another form of packaging material is provided with composite packagings made of combined layers of cardboard, polyethylene film and aluminium foil. Waste management of metal- coated films using classical methods is difficult, since they comprise a homogenous material, which cannot be subjected to direct regranulation. Metallic particles of various size suspended in the regranulated material obtained directly from such films pose a serious problem during potential application of such raw materials, thus such regranulated materials have no real useful value. In addition, direct regranulation of metal-coated films poses equipment problems because of presence of metal particles which amplify all inconveniences during processing, such as all raw material contaminations, or fast abrasion of processing equipment elements and frequent clogging of molten polymer filters. Waste containing metal-coated, used films are generated in relatively large quantities and pose a cumbersome waste despite the fact that methods of their separation into components are known.

Polyethylene is a type of polymer most often used in production of metal-coated films. After polyethylene is dissolved in an appropriately selected solvent, the obtained solution is filtrated and then the solvent is evaporated, leading to pure, polymeric raw material which can be processed into pure regranulate. Polyethylene regranulate is an inexpensive commercial product used as an additive to its fresh polymer in order to lower its price, or as the sole raw material for production of products with low requirements, such as refuse sacks or flower pots. Aluminium is the most often used film coating metal. Separated aluminium has the form of small pieces of foil which may be used in many ways, also including smelting. One of the directions of use of the separated aluminium may include, e.g. its facilitated milling and powdering to a different commercial form of this metal, i.e. aluminium powder or dust which have various applications.

Appropriate carrying out of the process of ingredient separation from metal-coated polymeric films may be provided under no pressure conditions and using relatively simple production equipment, further increasing profitability of such processes. Relatively low temperatures at which the separation processes takes place do not lead to any chemical degradation of polymer macromolecules, ensuring that initial rheological properties of the polymer are retained. An additional feature of the new technology includes the option of separating various polymer types from one another, which may be additionally present in the same batch of the raw material being processed. Correct selection of solvents used enable selective dissolution to be performed, thus separation of individual polymers may be achieved.

Separation of composite packaging containing, in addition to polyethylene and/or other plastics, aluminium foil and cellulose-based cardboard provides a more significant challenge. Different nature of these three combined materials leads to certain difficulties during separation and was a subject of various solutions of the method for their separation.

Polish patent application P-337131 discloses a method for material processing, said material containing composites of aluminium and plastics, such as aluminium bottle caps with a plastic coating, which includes the following stages: plastic pyrolysis under inert atmosphere, cracking or gassing gases or vapours evolving during pyrolysis and full combustion of coke remaining on aluminium during the pyrolysis stage. The evolved gases or vapours are returned to the process and used in pyrolysis as an inert, oxygen-free medium. A device enabling execution of the method, i.e. containing a pyrolytic drum, has also been described. This method does not take into account the presence of the cellulose ingredient in the processed waste and does not enable pyrolytic residues containing aluminium to be separated. PL181919 describes a method and a device for separate collection of layers from a laminated film containing several layers made of various materials, by tearing the layers off one another or by their separation. This method does not ensure separation of all three ingredients of a compact packaging, since it does not foresee tearing off cellulose fibres joined thermally with polyethylene films, and in case of mechanical treatment said fibres undergo degradation, losing their value. In addition, this method does not ensure adequate purity of individual fractions.

A processing method of polyolefin films coated with a metallic layer, in particular of metals such as zinc, copper, aluminium, silver and gold is disclosed in PL 201423. Said method includes the first stage in which metal-coated polyolefin films are exposed to a solvent at the temperature of 50-1 10°C for 2 to 30 minutes. The solvent includes a low- or medium-boiling point fraction of an oil obtained during polyolefin cracking, with a boiling point range of 50-170°C or 170-280°C. Weight ratio of the reagents is as follows: 1 part of waste film per 5-20 parts of solvent. The product of the first stage includes an extract of metal particles in a solvent, with particle size close to colloidal range, and polyolefin films devoid of metal. In the second stage, the extract is separated, preferably via sedimentation and centrifuging. Metal is obtained as a concentrate, and solvent is returned to the demetallisation or dissolution process. Next, metal-free polyolefin films are exposed to solvent at 120÷160°C, followed by cracking performed at 350÷500°C, to a mixture of hydrocarbon which is then distilled onto low-boiling, medium-boiling and high-boiling point fractions. However, the disclosed method is not appropriate for processing of composite packagings, since it does not foresee presence of the cellulose fraction in the processed waste mass nor it enables its separation, since the semi-ready product obtained after aluminium separation is subjected to pyrolytic processing.

Polish patent application P398044 provides a method for processing of wastes containing copper, ferromagnetic materials and plastics, in which the waste material is ground down and copper, ferromagnetic materials and plastics are separated, wherein the granulate is subjected to initial separation in a dry separator, in which light fraction of the granulate is separated using an air flow supplied upwards, towards a tilted table, then the remaining granulate is subjected to final separation in a wet separator, where light fraction of the granulate is separated from heavy fraction of the granulate using a water stream containing a non-foaming degreasing agent, supplied upwards towards the tilted table, followed by use of ferromagnetic separator which enables sorting of the light fraction into plastics and ferromagnetic materials, whilst the heavy granulate fraction is separated into copper and ferromagnetic materials. The disclosed method is successful only in the case of separation of mixtures containing separate particles of various polymer types and metals. Permanently joined aluminium and polyethylene foils, as well as the cellulose- based cardboard are not susceptible to the separation technique disclosed.

PL219475 discloses a method of aluminium recovery from post-production multiple material and packaging wastes, containing plastics, polyolefin groups as well as aluminium and paper, in which the obtained, plastified and partially fluid waste mixture is pumped to the main reactor and heated to a temperature not higher than 200°C, followed by dissolution of previously undissolved solid particles of the plastic in the medium of liquid, aromatic hydrocarbons, which after saturation flow via a piping to a compensating reactor, whereby the excess of the liquid polyolefin fraction, being the product of cracking taking place in both reactors, is pumped via pipes to a separation reactor, and volatile hydrocarbon fractions evolving during the process in all reactors are pumped via pipes to a scrubber where condensation takes place, and in addition, uncondensed gasses passed through a water filter are stored in a technical gas vessel for further use. This method does not foresee further separation of aluminium foil from the paper/cellulose fraction and is limited to solvent extraction of the polyethylene film comprising one of the ingredients of the composite material waste.

DE4028999 discloses a method of metal (I) recovery from composite materials (II) which includes separation of coatings on metal using solvents. Non-polar layers are removed by heating for 5-120 minutes with di- and/or tri- and/or tetra-methylbenzenes and/or ethylbenzene and/or isopropylbenzene (III) at 138.4-204°C under normal or elevated pressure, polar layers are removed by heating for 5-120 minutes with THF and/or dioxane at 60-200°C under normal or elevated pressure, paper and/or other cellulose- containing materials were removed by heating for 5-120 minutes at 80-200°C under their own vapour pressure with water containing 0.5-25 %wt. of a Cl-3 alcohol and/or C3-4 ketone, followed by metal separation. More specifically, this process is performed in a vessel equipped with a mixer using technical mixture of xylene isomers, preferably containing 1-4 %wt. of non-aromatic compounds, 19-23 %wt. of EtPh, 16-20 %wt. of p- xylene, 40-45 %wt. of m-xylene and 10-15 %wt. of o-xylene. This method does not include separation of aluminium particles and cellulose fibres, it only ensure extraction of waste from the soluble fraction of polymer.

Patent US No. 4,168,199 discloses separation of cellulose fibres from aluminium particles on vibration sieves with 0.25 mm aperture diameter. This method does not ensure complete removal of contaminations both from the separated cellulose and from the separated aluminium. Despite claims from the authors, an effective method of separation of the fibrous material and of aluminium flakes by co-sedimentation cannot be ensured nor guaranteed, since both particle types form clumped, fibrous precipitates, difficult to separate.

Patent CN101745518 discloses a processing method of a composite aluminium foil including the following stages: initial composite processing, soaking with a softening corrosion inhibitor, material kneading in the softening corrosion inhibitor followed by flotation using a method based on gravity which leads to, respectively, a plastic powder and an aluminium powder, dissolution of the plastic powder followed by its regeneration and granulation, similar steps are performed for the aluminium powder, next moisture is removed and finally a protective agent is added. This method is performed under ambient temperature and constant pressure, with low energy consumption. This process does not ensure proper separation of individual ingredients of the processed waste by flotation, since the flotation step is preceded by mechanical breakdown of the waste. The obtained product contains contaminated fractions. In addition, the process assumes waste milling, leading to destruction of cellulose fibres and their length is the measure of their market value.

EP0568791 describes a recycling process of packaging materials containing one or more synthetic polymers and/or metals and/or natural polymers, in particular composite packaging materials, in which the packaging materials for recycling are treated with a solvent containing aliphatic, naphtene or aromatic hydrocarbons or their hydrogenated products, or mixtures thereof used to dissolve the synthetic polymer. The processing takes place in a temperature range of 0-500°C. This method employs solvents comprising boiling fractions for primary and secondary oil refining, the boiling point range of which is 40-500°C. After synthetic polymer separation from the liquid phase, the insoluble fraction containing cellulose and aluminium is separated. The inventors do not attempt to provide a separation method for these ingredients, instead focusing on operations of pyrolytic processing of the polymer fraction of the waste.

CN101773923 provides a treatment method for composite products made of paper- aluminium-plastic or of composite packaging wastes made of plastic-aluminium. Said method includes the following steps: grinding down the composite packaging waste to grain diameter smaller than 3 cm followed by pyrolysis of broken down composite packaging wastes in a temperature of 450 to 500°C in anaerobic conditions, for 30 to 45 minutes, until a high purity aluminium foil is obtained, together with a flammable gas with high caloric value, generated as a conversion product during pyrolysis of plastics, in which about 40% to 60% of the flammable gas is used for pyrolysis of composite packaging wastes whilst the remaining flammable gas is collected for further use. However, this method leads to destruction of the cellulose fraction of the waste instead of its separation. Cellulose becomes gassed, leaving the aluminium fraction only.

ES2087013 discloses a method of polyethylene and aluminium recovery from sheets coated with an aluminium-polyethylene coating. This method uses organic solvents such as chlorinated and non-chlorinated hydrocarbons and includes the following steps: a) material breakdown, b) polyethylene extraction using the organic solvent, c) hot aluminium separation from solution obtained in step b), d) separation of dissolved polyethylene by cooling the solution down to below 60°C with precipitate separation, or by solvent evaporation, with each of the b), c) and d) steps is performed continuously or non- continuously. An alkane, an olefin and aromatic hydrocarbons or their mixtures containing chlorinated hydrocarbons are used as solvents. The extraction is performed in 50-200°C and under pressure in the range from atmospheric to 0.4 kPa. This method does not foresee separation of the cellulose fraction and separation of cellulose fibres from aluminium foil particles, thus it is not suitable for application with composite packaging waste. During studies on recycling methods of three-component composite packaging containing polyethylene, aluminium and cellulose, an initial, classical polymer extraction operation was used, employing appropriate solvents. These tests used xylene, since it is known for its good polyethylene solubility in elevated temperatures. The result of polyethylene extraction was always a mixture of cellulose fibres mixed with aluminium foil particles. This mixture could not be effectively separated in classical separation methods known in literature, such as: filtration, sedimentation or flotation. Both materials have relatively high densities and it is difficult to select an appropriate solvent with adequately high density for them. Using carbon tetrachloride as the separation medium, with density higher than that of cellulose, it seemed that separation of both particle types will be trivial. Unfortunately, introduction of a mixture of aluminium foil particles and cellulose fibres to carbon tetrachloride resulted in formation of three-dimensional structures made of cellulose fibres which blocked free precipitation of heavier aluminium particles. A foam of cellulose fibres gathered on the surface of liquid, containing a part of trapped aluminium particles, while on the bottom of the vessel a precipitate of aluminium particles deposited, containing a trapped part of cellulose fibres. To our surprise it turned out that separation of potential clumps of both particle types may be efficiently performed by placing a system of horizontal, thin strings in the sedimentation zone, vibrating slowly transversely to the precipitation - floating direction. These vibrations ensure separation of particle clumps into individual ingredients and floating or precipitation in the medium, according to their respective natures. Thanks to the use of vibrating strings it was possible to use higher density of the separated suspension and to increase process efficiency, obtaining very pure aluminium fraction on the bottom of the vessel, and the cellulose fraction floating on the surface.

The studies undertaken on the development of a separation technique for both ingredients of metal-coated foil led to the discovery of the innovative process. A solution was developed which may be successfully used even on large scale. To our surprise it turned out that by selecting specific solvents it is possible to dissolve the main polymeric ingredient of the film selectively, and other, undissolved and suspended metallic particles may be separated later using classical methods, such as filtration. The new separation method of metal- coated polymer film wastes enables management of this stream of hitherto cumbersome type of packaging waste. As a result of appropriate solvent composition selection and a correct dissolution method, aluminium, comprising the most often used metal in such applications, may be separated from the base polymer film. Solvents used in the process may be recycled. The separated aluminium has the form of fine flakes and is a commercial recycled material. At the same time, the purified polymer subjected to regranulation may be used as a recycled raw material for production of plastic products, such as refuse sacks, for example. Thanks to correct design of the entire process, maximum heat recuperation and minimisation of operation costs is ensured, thus making the method profitable.

The presented invention includes a separation method of composite packaging ingredients, containing a polymer film, aluminium and/or cellulose and including steps in which the waste is initially broken down into 10 cm x 10 cm pieces or smaller, preferably 3x3 cm or smaller, an extraction of the polymer fraction is performed using xylene or other organic solvents such as benzene, toluene, cumene, ethylbenzene, naphtha, chlorobenzene, dichlorobenzene, bromotoluene, followed by separation of insoluble ingredients by grinding them down in a mixer, the precipitate of aluminium and cellulose particles is transformed into a liquid suspension with density higher than cellulose density and lower than aluminium density which is next dosed into a separator, whilst polymer solutions are evaporated in order to regenerate the solvent, and the initial polymer ingredient of the processed waste is separated.

Preferably, insoluble particles of metallic aluminium and cellulose are filtered after extraction of polymer ingredients.

In a preferred embodiment of the invention, the process of polymer fraction extraction is performed in elevated temperature, preferably at the boiling point of the solvent, more preferably the process of waste polymer fraction extraction is performed in elevated temperature and under elevated pressure, in temperature higher than normal boiling point of the solvent. In a preferred embodiment of the invention, the process of polymer fraction extraction is performed using a single or multiple solvent portions and the process is performed periodically or continuously.

In another preferred embodiment of the invention, the precipitate of aluminium and cellulose particles is dried before their separation and washed using clean solvent in order to clean and remove residues of the polymer solution.

In another preferred embodiment of the invention, the insoluble ingredients suspension is introduced to half the depth of the separation tank.

In another preferred embodiment of the invention, the suspension after separation of insoluble ingredients is introduced onto a system of horizontal strings fixed onto frames in groups, with a string distance of 10 to 30 mm, preferably 15 mm to 20 mm. Preferably, the strings are caused to vibrate with a frequency of 0.5 Hz to 5 Hz, more preferably of 1 Hz to 2 Hz with amplitude of 1 mm to 45 mm, preferably 10 to 15 mm, preferably in the horizontal plane.

In another preferred embodiment of the invention, every second layer of strings in the given group is caused to vibrate in the same phase and opposite to other layers in the same group.

The invention also provides a device for separation of composite packaging ingredients containing a polymer film, aluminium and/or cellulose, in which a tank (1) contains sections with groups of horizontal strings (2, 3) located above and below the level where suspension is introduced, fixed on frames and set up in groups with string distance of 10 to 30 mm, more preferably 15 mm to 20 mm. Preferably, the level at which the suspension of insoluble ingredients is introduced is located at half the depth of the separation tank.

In case of another preferred embodiment of the invention, every group of strings (2,

3) contains 1 to 50 layers, preferably 5 to 30, more preferably 12 to 22 layers of strings.

Preferably, the strings are caused to vibrate (5) with a frequency of 0.5 Hz to 5 Hz, more preferably of 1 Hz to 2 Hz with amplitude of 1 mm to 45 mm, preferably 10 to 15 mm, preferably in the horizontal plane. Preferably, every second layer of strings in the given group is caused to vibrate in the same phase and opposite to other layers in the same group.

The invention is presented in the drawings, in which Fig. l presents schematically the recovery process of aluminium, polyethylene and cellulose, Fig. 2 presents schematically a cross-section of the separation tank for aluminium particles and cellulose.

The examples are presented as means of illustration of the preferred embodiments of invention only, without the intention of limiting the scope of the claims.

Example 1

Waste of metal-coated packaging film was processed, comprising two layers of polyethylene foil separated with aluminium foil and used for product protection against light thanks to the use of opaque layer of aluminium. Separately performed composition analysis of the waste film showed aluminium content at the level of 12.3%. Polyethylene comprised the remaining part of the material. The mass fraction of paint used to provide marks painted on the film was not determined. The waste was initially broken down into pieces, max. 3 cm x 3 cm, in a shredder. 1,750 kg of waste film was introduced into the 5 m reaction tank, vented through a reflux condenser.

The tank was closed and filled with 2,700 kg of xylene. The xylene stream was collected at the bottom of the tank using a pump ensuring xylene circulation through externally heated heat exchanger. The solvent was heated in the heat exchanger. The mixture in the tank reached its boiling point after 4 hours. Heating of the circulating solvent was limited, and the mixture was kept at mild reflux for 3 hours. Complete dissolution of polyethylene (polymer) elements of the waste in the solvent took place during that time. The solvent was poured from the tank, including the floating suspension of aluminium particles, onto a thick metal mesh on which aluminium flakes were separated. Flakes collected in the filter were then washed using 300 kg of hot xylene in order to remove residues of the polyethylene solution from between the flakes. The filtrate, including the washing solution, was directed to a storage tank for further processing. A steam stream was passed through the deposit of aluminium flakes and particles in order to remove residues of the organic solvent, and then cooled. 206 kg of aluminium was thus obtained. Polyethylene solutions in xylene were concentrated by evaporating xylene, which was condensed and collected in a storage tank for use with the next batch. Molten polyethylene remained in the evaporator, which was next granulated in a separate line, in which 1533 kg of granulate was obtained. Example 2

Waste generated during recycling of cardboard packaging is separated. It includes clumps of packaging elements and polyethylene film, cellulose-based cardboard and aluminium foil. Approximate waste composition is polyethylene 20%, cellulose 75% and aluminium 5%. 1500 kg of the waste was introduced into a 5 m tank reactor vented through a reflux condenser cooled using circulation water. The tank was closed and filled with 2,600 kg of xylene. The xylene stream was collected at the bottom of the tank and heated in an external exchanger, then returned to the tank. After 3.5 hours the mixture in n

the tank reached its boiling point, heating of the circulating solvent was limited and the mixture was kept under mild reflux for another 3 hours. Complete dissolution of polyethylene (polymer) elements of the waste in the solvent took place during that time. The solvent was poured from the tank and directed to a storage tank for further processing. The mixture in the reactor was treated with 1,000 of hot xylene and flushed for 30 minutes using a circulation pump. Once the flushing was completed, xylene was poured into the tank containing the first part of xylene. Used xylene containing dissolved polymer was collected from the storage tank and directed to an evaporator. Xylene was distilled off in the evaporator and directed to a storage tank of pure xylene, then used in another production cycle. Residue after xylene evaporation contained molten polymer, mainly polyethylene, which comprised one of the products of waste separation. It was subjected to granulation, which yielded 552 kg of polyethylene granulate.

The mixture remaining in the tank reactor included cellulose and pieces of aluminium foil. The reactor was flushed with hot steam in order to remove xylene residues from the mass remaining in the reactor. Then the mixture was cooled to room temperature using cold water. The mass, covered with water, was mixed mechanically using a fast- rotation mixer in order to separate clumps of fibres and foil pieces. A loose pulp containing cellulose fibres and small aluminium foil flakes was obtained. The pulp was filtered by removing water from the tank and then dried, obtaining loose material made of mixed cellulose and aluminium particles. The difference between their densities was used in their separation. Cellulose fibres from cardboard elements of the waste had the density of 1.5 g/cm and the aluminium foil - 2.7 g/cm . 3,500 kg of carbon tetrachloride with density of 1.6 g/cm was added to the tank reactor, to the material, in order to obtain a suspension. The suspension of particles in carbon tetrachloride was introduced at the half the height of the cuboidal tank. Above and below the introduction zone, thin steel wires were fixed onto frames, forming a three-dimensional web every 15 mm. Web strings were installed as 20 layers over and 20 layers under the point of suspension introduction. Each layer of the strings performed pendulum-like vibrations in the horizontal plane, with identical vibrations including every second string layer. Motion of thin wires in the liquid did not cause a mixing effect and did not result in transverse motions of the liquid. Use of carbon tetrachloride resulted in heavier aluminium particles precipitating onto the tank bottom, while lighter cellulose fibres floated onto the surface. Pouring the fractions from the surface in the tank and from the bottom of the tank ensured collection of both particle fractions. By carefully pouring the bottom part of reactor tank contents, the suspension of aluminium particles in carbon tetrachloride was collected. This mixture was filtered on a filter, thus a precipitate of aluminium foil particles was obtained, while the pure carbon tetrachloride was returned to the storage tank to be used in the next production batch. Foil particles on the filter were flushed with water in order to remove residues of carbon tetrachloride and dried, yielding 74.5 kg of aluminium. The top fraction from the reactor was poured and filtered on a sieve filter, washed with a stream of water in order to remove carbon tetrachloride residues and dried. 1227.3 kg of light brown, fibrous cellulose was obtained. No liquid sewage is generated in the process, and all media such as xylene, water, carbon tetrachloride are regenerated and returned to the production line. The separation process is presented schematically in fig. 1. Fig.2. presents schematically a cross-section through the tank used in separation of aluminium and cellulose particles. 1 denotes the tank, 2 and 3 are, respectively, the upper and the lower string groups sections, 4 denotes a channel used to introduce the suspension to the central section and 5 denotes vibration directions of string groups.