METHOD FOR PROCESSING THE WASTE CREATED BY RECYCLING PAPER FROM USED BEVERAGE CARTONS

Abstract

A method for processing, and gaining value from, waste which is created by recycling paper from used beverage cartons, and a processing line for performing this method are disclosed. In Phase I, the flake size of the input material is reduced, the rough waste and dust waste removed from it, the thus treated input material is separated into fraction, containing mainly non-foil plastic, and fraction containing mainly PE foil and PE+AL foil. In Phase II, fraction containing mainly PE foil and PE+AL foil undergoes washing in a water-based formic acid solution and is separated into fraction, containing mainly polyethylene, and fraction, containing mainly aluminium. During Phase III, fraction is processed into aluminium and in Phase IV, fraction is processed into polyethylene granules, then, in Phase V, fraction has the admixture removed and is processed into regrind or granules.

Claims

1-15. (canceled)

16. A method of processing waste created after recycling paper from used beverage cartons wherein: during Phase I—preparing and sorting the input material—the input material is shredded and from this shredded material, rough waste made up of heavy materials and dust waste is removed, and then the input material treated in this way is separated into fraction, containing mainly non-foil plastics, and fraction containing mainly PE foil and PE+AL foil; and during Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—fraction containing PE+AL foil, undergoes washing in a formic acid water solution and is separated into fraction, containing mainly polyethylene and fraction containing mainly aluminium.

17. The method according to claim 16, wherein, during Phase I, the fraction, containing mainly PE foil, is further separated from the fraction, containing mainly PE+AL foil, which always has at least one layer each of polyethylene and aluminium.

18. The method according to claim 16, wherein, it further involves: Phase III—processing aluminium—in which the fraction containing mainly aluminium is processed into aluminium; and/or Phase IV—processing polyethylene—in which the fraction containing mainly polyethylene is processed into polyethylene granules; and/or Phase V—processing non-foil plastics—where fraction containing mainly non-foil plastics has any admixture removed and is processed into regrind or granules.

19. The method according to claim 16, wherein: during Phase I—preparing and sorting the input material—the input material is shredded into particles with a maximum size of 20 cm, with the rough waste being separated by air sorting, and further the dust waste is removed and the moisture of the material reduced by dry cleaning, after which, air sorting separates fraction, containing mainly non-foil plastics, and the remaining fraction containing mainly PE and PE+AL foil is cut; and during Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—fraction containing PE+AL foil undergoes hot washing in a water-based working solution of 15 to 30% formic acid by weight at temperatures from 40 to 80° C., whereby fraction, containing mainly aluminium in particle form is separated from the working solution by centrifugal treatment.

20. The method according to claim 19, wherein: during Phase I—preparing and sorting the input material—the input material is shredded in a shredder, the rough waste is removed in the first air separator, the dust waste is removed and the moisture content of the material reduced in the dry cleaning machinery, after which, in at least one of the air separators, fraction, containing mainly non-foil plastics is removed and the remaining material is cut in a cutting mill; and during Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—solid particles are removed from the used working solution by decanting using a decanter centrifuge.

21. The method according to claim 20, wherein, during Phase I, the fraction, containing mainly PE foil, is further separated from the fraction, containing mainly PE+AL foil, which always has at least one layer each of polyethylene and aluminium, and wherein, during Phase I the remaining material cut in a cutting mill is further separated in the next air separator into fraction, containing mainly PE foil, and fraction, containing mainly PE+AL foil.

22. The method according to claim 18, wherein, during Phase III—processing aluminium—fraction, containing mainly aluminium is initially dried in a rotation kiln and then the aluminium is smelted in a kiln under a protective nitrogen atmosphere.

23. The method according to claim 18, wherein: during Phase IV—processing polyethylene—fraction, containing mainly polyethylene is processed into polyethylene granules; and during Phase V—processing non-foil plastics—fraction, containing mainly non-foil plastics, has the admixture removed and is processed into regrind or granules.

24. The method according to claim 16, wherein, during Phase II the working solution is a water-based formic acid solution with 15-30% formic acid by weight, the ratio of the bulk volume of the input fraction, containing mainly PE+AL foil, to the working solution is 1:100 to 1:10 and the input fraction is intensively stirred in the solution for 5 to 30 minutes, with an advantage of 7 to 15 minutes at a working solution temperature of up to 80° C., with an advantage of 40° C. to 70° C.

25. A processing line for performing the method of processing the waste created after recycling paper from used beverage cartons according to claim 16, wherein it includes: machinery for Phase I—preparing and sorting the input material, which includes a shredder, air separator for removing rough waste, dry cleaning machinery for removing paper fibre and dust contamination and for reducing the moisture content of the material, a cutting mill for cutting the foil and at least one air separator for separating the non-foil plastics from the foil; and machinery for Phase II, separating PE+AL foil into polyethylene and aluminium and their sorting into fraction, containing mainly polyethylene and fraction, containing mainly aluminium, which includes stirring machinery for soaking the PE+AL foil in a working solution heated to a working temperature, a reaction tank for intensively mixing the PE+AL foil in the working solution, machinery for removing the solution, machinery for separating fraction, containing mainly polyethylene, and fraction, containing mainly aluminium, and machinery for regenerating the working solution.

26. The processing line according to claim 25, wherein, the machinery for Phase I—preparing and sorting the input material further includes another air separator for separating fraction, containing mainly PE foil, and fraction, containing mainly PE+AL foil.

27. The processing line according to claim 25, wherein, for Phase II the mixing machinery is designed as a mixing screw, the reaction tank has dimensions for intensively stirring PE+AL foil in at least ten times the volume of working solution, the machinery for separating the working solution is designed as a draining screw, the machinery for separating fraction, containing mainly polyethylene, from fraction, containing mainly aluminium, includes a friction washing machine and centrifuge.

28. The processing line according to claim 25, wherein, the machinery for regenerating the working solution during Phase II contains a collection tank for gathering the solution, which is connected by input pipes to the batch dispensing machinery for delivering formic acid into the working solution and to a decanter centrifuge for removing aluminium particles and which is connected by output pipes to the mixing screw and reaction tank, a collection tank for gathering the working solution, which is connected by input pipes to the draining screw, a friction washing machine, a centrifuge and a screw press and which is connected by output pipes to a decanter centrifuge and a collection tank and a heat exchanger for heating the working solution.

29. The processing line according to claim 27, wherein, during Phase II, hot air drying machinery, for drying fraction, and a screw press, for removing remnants of the working solution from fraction, are connected to the friction washing machine and the centrifuge.

30. The processing line according to claim 25, wherein it also includes: machinery for Phase III—processing aluminium—which includes in particular a rotation kiln for drying the material and a batch furnace with a protective atmosphere for smelting the aluminium; and/or machinery for Phase IV—processing polyethylene—which includes, in particular, an extruder; and/or machinery for Phase V—processing non-foil plastics—which includes a shredder, washing machine and air separator.

31. The method according to claim 17, wherein, it further involves: Phase III—processing aluminium—in which the fraction containing mainly aluminium is processed into aluminium; and/or Phase IV—processing polyethylene—in which the fraction containing mainly polyethylene is processed into polyethylene granules; and/or Phase V—processing non-foil plastics—where fraction containing mainly non-foil plastics has any admixture removed and is processed into regrind or granules.

32. The method according to claim 17, wherein: during Phase I—preparing and sorting the input material—the input material is shredded into particles with a maximum size of 20 cm, with the rough waste being separated by air sorting, and further the dust waste is removed and the moisture of the material reduced by dry cleaning, after which, air sorting separates fraction, containing mainly non-foil plastics, and the remaining fraction containing mainly PE and PE+AL foil is cut; and during Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—fraction containing PE+AL foil undergoes hot washing in a water-based working solution of 15 to 30% formic acid by weight at temperatures from 40 to 80° C., whereby fraction, containing mainly aluminium in particle form is separated from the working solution by centrifugal treatment.

33. The method according to claim 18, wherein: during Phase I—preparing and sorting the input material—the input material is shredded into particles with a maximum size of 20 cm, with the rough waste being separated by air sorting, and further the dust waste is removed and the moisture of the material reduced by dry cleaning, after which, air sorting separates fraction, containing mainly non-foil plastics, and the remaining fraction containing mainly PE and PE+AL foil is cut; and during Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—fraction containing PE+AL foil undergoes hot washing in a water-based working solution of 15 to 30% formic acid by weight at temperatures from 40 to 80° C., whereby fraction, containing mainly aluminium in particle form is separated from the working solution by centrifugal treatment.

34. The method according to claim 19, wherein, during Phase III—processing aluminium—fraction, containing mainly aluminium is initially dried in a rotation kiln and then the aluminium is smelted in a kiln under a protective nitrogen atmosphere.

35. The method according to claim 20, wherein, during Phase III—processing aluminium—fraction, containing mainly aluminium is initially dried in a rotation kiln and then the aluminium is smelted in a kiln under a protective nitrogen atmosphere.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0034] The attached drawings include:

[0035] FIG. 1 A simplified schematic diagram of the entire process of processing and monetizing waste according to the advantageous design of the invention

[0036] FIG. 2 Phase I—preparing and sorting the input material according to the advantageous design of the invention

[0037] FIG. 3 Phase II—separating the PE+AL foil into polyethylene and aluminium and their sorting according to the advantageous design of the invention

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Example No. 1

[0038] Paper mill waste created after recycling paper fibres from used beverage cartons was processed using the invention method in five phases, on a processing line designed according to the invention in the following manner:

[0039] Phase I—preparing and sorting the input material—is set out in the schematic diagram in FIG. 2. The objective of the Phase I operation was to remove contamination from the I-A input material, dry it and separate it into fraction I-D, containing mainly non-foil plastic, e.g. packaging lids and tops (mostly made from high density polyethylene HDPE), and fraction containing mainly PE and PE+AL foil that can be preferably separated into fraction containing mainly PE+AL foil made from polyethylene and aluminium and fraction I-E containing mainly PE foil. The main steps in Phase I and the machinery used at the various sections where these steps are performed are described in the following table.

TABLE-US-00001 Section No. Machine Section description 11 Shredder The shredder is used to break down the input material packages and pulverize it into cca 10-20 cm sized flakes. This is a regular machine used to crush solid materials. 12 Air separator The air separator removes heavy contaminants (e.g. metal, stone, glass) and protects subsequent machinery from damage. 13 Dry cleaning Dry cleaning eliminates most of the paper machine, e.g. fibre and dust contamination. It also centrifuge reduces the moisture of the material, improving the sorting quality in the next steps. 14 Air separator The air separator step separates non-foil plastic (e.g. lids and tops) from the foil (PE + AL foil and PE foil). A silo is placed before the air separator to ensure a regular flow of material into it and thus high quality sorting. 15 Cutting mill In this step the material (mainly foil with remnants of non-foil plastic) is cut into cca 2 cm sized flakes. The uniform flake size makes it possible to sort out the remaining non-foil plastic in the next step. 16 Air separator In this step the foil (a mixture of PE and PE + AL foil) is separated from the non-foil plastic. A silo is placed before it to ensure a regular flow of material into the separator and thus high quality sorting. 17 Air separator In this step the PE + AL foil, and PE foil flakes are separated from each other. This step is advantageous for the industrial application of the technology as it reduces the volume of material which undergoes chemical separation, thus reducing operating and investment costs.

[0040] The result of Phase I waste processing was 5 output fractions (denoted by the Roman numeral I, a hyphen and letters B to F), whose properties are set out in the next table.

TABLE-US-00002 Fraction No. Material Material description I-A Input material Waste consisting of PE + AL foils, PE foils, lids and tops of non-foil plastic, paper fibres and other contaminants, e.g. metals, plastics and textiles. I-B Rough waste Waste from heavy materials, e.g. metals, stones, glass. There is low moisture for this fraction. I-C Dust waste Waste from dry cleaning made up of mainly paper fibres (>50% weight), a mixture of various plastics and aluminium dust. The moisture of this fraction is >40% of its weight. I-D Fraction containing A mixture of non-foil plastic (mainly mainly non-foil HDPE) contaminated with e.g. other plastics plastics and textiles. The moisture of this fraction is <5% of its weight. I-E Fraction containing PE foil contaminated with aluminium mainly PE foil (<3% weight) and other plastics (<2% weight.). The moisture of this fraction is <5% of its weight. I-F Fraction containing Foil made up of a number of layers of mainly PE + AL foil polyethylene and a layer of aluminium. The moisture of this fraction is <5% of its weight.

[0041] Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting—is schematically set out in FIG. 3. The main objective of this phase was to breakdown fraction I-F, containing mainly PE+AL foils into fraction II-A containing mainly polyethylene (in flakes) contaminated with remnants of aluminium, paper fibres and other plastics (overall contamination <5% weight), and fraction II-B containing mainly aluminium, where this fraction was contaminated with paper fibres and plastics (overall contamination >30% weight). These two fractions were separated so that they could be further processed in an advantageous manner. The main steps of Phase II and the machinery used at the different sections where the steps were performed are set out in the following table.

TABLE-US-00003 Section No. Machine Section description 21 Set of A set of machines which are normally used machinery for washing soiled plastics (mainly PET) in for hot lye was used to breakdown the PE + AL foil washing with a formic acid working solution. The different components of the hot washing machinery (21a to 21i) are described in the following tables. 22 Friction A friction washing machine removes the washing working solution and aluminium (contaminated machine with plastic and paper fibres) from the polyethylene. 23 Centrifuge The centrifuge is the last step of the mechanical drying. At the same time the part of the remaining aluminium is also removed. 24 Hot air Hot air drying further reduces the PE foil dryer moisture to ca 2% weight. The low moisture positively influences the following re-granulation process. Also, by reducing the moisture the volume of HCOOH which is carried on through the process is minimized. This is essential for restricting acid vapour (smell) and restricting its corrosive effects further on in the process. The air used during drying is taken off for vapour treatment (see 25) 25 Filter for A water filter is used to collect HCOOH vapour. treating The solution is cleaned of acid in a biological vapour waste water treatment plant. Alternatively, the formic acid can be recycled from the water solution by distillation or electro-dialysis.

[0042] The set of hot washing machines, set 21, used in this example is regularly used for washing soiled plastics (mainly PET bottles) in lye. Set 21 was made up of two parts; 1) machinery which processed the material (fraction I-F containing mainly PE+AL foil, and 2) machinery which prepared and regenerated the working solution. These two parts of set 21 are described in more detail in the following table.

[0043] The machinery used for processing fraction I-F:

TABLE-US-00004 Section No. Machine Section description 21a Mixing In the mixing screw the PE + AL foil is soaked screw and sprayed with the working solution which is heated to the working temperature. This step a) heats the foil so there is no drop in temperature in the reaction tanks, and b) improves the foil properties for processing and transporting. 21b Silo From the silo, the foil is divided into the separate reaction tanks - this step is necessary because the reaction tank process (separating PE and AL) is done in batches (all other sections are a continual process). 21c Reaction In the reaction tanks the material is intensively tanks stirred in the working solution at a given temperature and for a given period to separate the PE and AL. 21d Draining In the draining screw part of the working screw solution is removed from the processed material.

[0044] Machinery for preparing and regenerating the working solution:

TABLE-US-00005 Section No. Machine Section description 21f Collection The working solution in the mixing screw tank 1 and reaction tanks is topped up from collection tank 1. The working solution is heated to the required temperature using heat exchanger 21i. The working solution is added to the required level using batch dispensing machine 21e 21h Collection The working solution from the draining screw tank 2 21d, friction washing machine 22, centrifuge 23 and screw press 26 is collected in collection tank2. Part of the solution is then led to the decanter centrifuge 21g and part directly to collection tank 21f. 21g Decanter The decanter centrifuge removes solid centrifuge particles (aluminium, plastics and paper fibres) from the working solution.

[0045] The set of hot washing machinery, set 21, used the following method for processing fraction I-F:

[0046] The working solution was a 20% formic acid water solution (20% HCOOH and 80% water by weight). The volume ratio of fraction I-F to the working solution was 1:20. Fraction I-F was intensively stirred for 15 minutes at solution temperature of 50° C.

[0047] The following table sets out the characteristics of the main flow of the material which was the result of processing fraction I-F during Phase II.

TABLE-US-00006 Fraction No. Material Material description II-A Fraction containing Polyethylene flakes contaminated with mainly polyethylene aluminium and other plastics (overall contamination <2% weight) for processing in Phase IV - polyethylene re-granulation. II-B Fraction containing Aluminium contaminated with paper fibres mainly aluminium and plastics for processing in Phase III.

[0048] Fraction II-B containing mainly aluminium was saved for further processing. Fraction containing mainly polyethylene (e.g. in flake form) was processed in Phase IV in re-granulation machinery which contained special filters enabling material with large amounts of contaminants to be processed, in the case of this example this was up to 5% of the weight. Fraction I-D containing mainly non-foil plastics sorted from the foils in air separators was processed in Phase V, where this processing was performed in a regular manner on regular machinery used for recycling plastics contaminated with other material. At this step of the process the input material was cleaned of any admixture and processed into regrind.

Example No. 2

[0049] Waste from the recycling of paper fibres from used beverage cartons from the Papierfabrik Niderauer Mühle GmbH paper mill was processed on a line designed to perform the invention method in the same way as Example. No. 1, where in this case 896 kg of I-A input material with 24% moisture by weight, i.e. 680 kg of dry state material was processed in Phase I—preparation and sorting of input material. Shredder 11, air separator 12, dry cleaning machinery 13, first silo 18, air separator 14, cutting mill 15, second silo 18, and air separators 16 and 17 were used in the Phase I processing.

[0050] From processing the I-A input material, 5 kg of rough waste I-B, a mix of heavy materials, e.g. metals, stone and glass was produced. 168 kg of dust waste I-C, a mixture from the dry cleaning made up of mostly paper fibres, a mix of various plastics and aluminium dust was also obtained. The moisture of the I-C waste was measured at 42-43% by weight, thus the dry weight of the waste was 97 kg. 128 kg of fraction I-D containing mostly non-foil plastic in the form of pieces, a mixture of mainly HDPE contaminated with e.g., foil and textiles was also obtained. 278 kg of fraction I-E was obtained which contained mainly PE foil, a mixture of PE foil contaminated with aluminium and other plastics. The moisture was measured at 3% weight, thus the dry material was 269 kg. There was also 126 kg of fraction I-F obtained containing mainly PE+AL foil made of polyethylene and aluminium. The moisture here was measured at 2-3%, therefore the dry material weight was 122 kg.

[0051] The next step involved processing fraction I-F containing mainly PE+AL foil in Phase II—separating PE+AL foil into polyethylene and aluminium and their sorting. The separation was performed using a formic acid (HCOOH) water solution with a 20% concentration by weight, at 50° C., for 15 minutes, where the bulk volume of the flake form fraction I-F before processing was 5% of the total volume of flakes and liquid. The quality of fraction II-A containing mainly polyethylene was sufficient for processing in Phase IV. and the quality of fraction II-B containing mainly aluminium contaminated with paper fibres and plastic was sufficient for Phase III processing by smelting aluminium in a protected atmosphere.

INDUSTRIAL APPLICABILITY

[0052] The invention method is applicable in the waste recycling industry for processing waste from paper mills which recycle used beverage cartons. Processing and making value from waste and using the processing lines with this method, according to the invention, makes it possible to monetize waste and further use it whilst maintaining low costs.

TABLE-US-00007 List of numbered references 11 shredder 12 air separator 1 13 dry cleaning machine 14 air separator 2 15 cutting mill 16 air separator 3 17 air separator 4 18 silo 21 hot washing machinery set 21a mixing screw 21b silo 21c reaction tank 21d draining screw 21e batch dispensing 21f collection tank 1 21g decanter centrifuge 21h collection tank 2 21i heat exchanger 22 friction washing machine 23 centrifuge 24 hot air drying 25 vapour treatment 26 screw press 27 silo 28 concentrated acid tank I-A input material I-B rough waste (metals, stones, glass) I-C dust waste (paper fibres, plastics and aluminium dust) I-D fraction containing mainly non-foil plastics I-E fraction containing mainly PE foil I-F fraction containing mainly PE + AL foil II-A fraction containing mainly polyethylene II-B fraction containing mainly aluminium