WO2016004956A2

WO2016004956A2 - Purification unit

Info

Publication number: WO2016004956A2
Application number: PCT/DK2015/050207
Authority: WO
Inventors: Claus WOLDBYE
Original assignee: Gips Recycling Danmark A/S
Priority date: 2014-07-08
Filing date: 2015-07-08
Publication date: 2016-01-14
Also published as: WO2016004956A3; EP3166727A2

Abstract

Method for separating a combined material where said material at least comprises gypsum and paper, where said combined material (in a step) a) is led into a first wind sifter in which wind sifter a first upwards airflow is regulated such that a first fraction comprising heavier particles of the material falls to the bottom of the wind sifter and are evacuated through a bottom outlet, whereas a second fraction comprising lighter particles and paper is evacuated through an upper outlet; b) wherein the second fraction (evacuated from the upper outlet) is introduced into a second wind sifter, where a second upwards airflow, said second upwards airflow being slower than the first upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said second wind sifter, where the paper and any heavier particles are extracted as a third fraction from the second wind sifter, and transferred to) a cleaning unit, in which unit the paper is cleaned from any loose or adhering particles, gypsum or other matter, after which cleaning process the cleaned paper is transferred to further processing, and the loose or adhering particles, gypsum or other matter, as well as any heavier particles are collected separately.

Description

Purification unit Field of the Invention

The present invention relates to a purification unit, i.e. a method for using such purification unit as well as an apparatus having the various features making up such a puri- fication unit.

Background of the Invention

In the building industry and other industries such as for example certain parts of the manufacturing industry significant amounts of waste consisting of dry paper and cardboard mixed with several other materials and/or paper waste where other materials weakly or strongly is adhered to the surface is generated. These types of waste are relatively complex in that they usually consist of various materials which by themselves would be valuable for reuse, but when mixed together or adhered together become very expensive and/or very difficult to purify into valuable recyclable materials such as for example recyclable clean paper.

It is known in the art to separate and recycle gypsum from such boards. One example is known from DE 20004472, where a board is cut and successively introduced into a wind sifter and thereafter into a cyclone device. The cyclone device will cause the introduced material to circulate carried by an airflow inside the device, and in this manner separate heavier items from lighter items. After these separation steps the paper and remaining gypsum dust/particles is passed over a sieve in order to separate the remaining gypsum from the paper fraction. Following these steps the paper fraction is disposed in a container for possible reuse. The process described in DE20004472 will however leave a paper fraction with an adhered gypsum content much too high to en- able reuse of the paper. As the process according to DE20004472 focuses on regenerating as much gypsum as possible, the remaining fractions, once as much gypsum as possible with the means available, has been retrieved is not important. Object of the Invention

It is therefore an object of the present invention to provide a dry and fast process in order to regain a high rate of valuable- reusable material from a stream of mixed or combined material waste. Description of the Invention

The present invention is directed to a method as well as an apparatus which in a dry process can separate those complex waste materials into purified material fractions, particularly remove material that adheres to paper surfaces, such that a purified paper fraction may be the end result without destroying the structure of the paper as such.

Where appropriate the terms upstream and downstream shall mean the combined materials travelling direction through the apparatus and as following from the description of the method. The invention addresses this by providing a method for separating a combined material where said material at least comprises gypsum and paper, where said combined material (in a step) a) is led into a first wind sifter in which wind sifter a first upwards airflow is regulated such that a first fraction comprising heavier particles of the material falls to the bottom of the wind sifter and are evacuated through a bottom outlet, whereas a second fraction comprising lighter particles and paper is evacuated through an upper outlet; and b) where the paper sorted in the wind sifter is led into a cleaning unit, in which unit the paper is mechanically cleaned from any loose or adhering particles, gypsum or other matter, after which cleaning process the cleaned paper is transferred to further processing, and the loose or adhering particles, gypsum or other matter, as well as any heavier particles are collected separately. The combined material is typically delivered in the shape of already reduced and partially cleaned paper fraction, for example the paper fraction derived by the applicant's earlier method and apparatus according to EP 1421995 Bl or alternatively for example DE20004472U1. A wind sifter is a device in which inside a housing an airstream is provided from the bottom towards the top such that particles or objects which can float or be lifted by the air stream are moved to the top of the wind sifter, whereas heavier items which due to the influence of gravity are not able to float or be lifted by the airstream will fall towards the bottom of the wind sifter. In this manner it is possible by means of a wind sifter to separate a material stream into lighter or heavier particles in relation to the upwards airstream. Naturally, the faster the airstream, the heavier the objects which may be moved to the top of the wind sifter are.

Furthermore, inside the housing of the wind sifter, one or more baffles may be provided such that heavy articles which fall downwards against the airstream may impact the baffles and in this process potentially fracture or loosen some of the adhered material such that a further segregation of the material stream is carried out through the wind sifter. Advantageously the wind sifters, i.e. both the first and second wind sifters may instead have a Z shape, such that the cross section of the air passage remains substantially constant. Typically a wind sifter will have 2-5 zig-zag's. In this manner the airflow may be kept constant. Naturally the wind speed inside the wind sifter will be adjusted such that the desired effect is obtained, i.e. the desired output is collected at the desired outlets.

From the bottom outlet of the first wind sifter one or more conveyors, the conveyors may for example have different characteristics, will convey the mainly paper fractions to a cleaning unit. In the cleaning unit the paper is mechanically cleaned, meaning that the paper is impacted to such a degree that any adhering or loosely adhering material will be liberated from its connection to the paper. This material, liberated from the paper will be collected separately and will mainly consist of material dust, preferably gypsum dust, and fibers, typically paper fibres liberated by the preceding process.

The cleaning unit will furthermore have means to evacuate or expel the cleaned paper, which may then be collected for reuse. The product leaving the cleaning unit will have a quality where the paper fraction is suitable for pellets used as fuel, or other purposes where a certain degree of foreign matter, in particular gypsum may be tolerated. In a further advantageous embodiment the method is further distinguished in that after step a) a second wind sifter is introduced wherein the second fraction (evacuated from the upper outlet) is introduced into a second wind sifter, where a second upwards airflow, said second upwards airflow being slower than the first upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said second wind sifter, where the paper and any heavier particles are extracted as a third fraction from the second wind sifter, and transferred to the cleaning unit in step c).

From the upper outlet of the first wind sifter lighter particles and paper are evacuated and by conveying means transported to the second wind sifter. In this wind sifter the airstream is again adjusted such that lighter and more heavy particles will be separated. However, the airstream here will be slower than the airstream in the first wind sifter, such that the paper will be allowed to float to the bottom of the wind sifter and be evacuated through the bottom outlet in the second wind sifter. The upper outlet will mainly evacuate dust, plastic foils and loose fibers which will be lead to a filter in order to separate these particles from the air which may then be expelled from the apparatus. The collected particles may be stored for further use or may be disposed of appropriately.

In a still further alternative embodiment the first wind sifter is replaced by a device for sorting lighter items from the material, where said device comprises optical recognition means, particularly a laser and a perforated conveyor on which the material is transported, where air-jets are arranged below said perforated conveyor such that as the optical recognition means detects lighter items in the material, the air-jets are activated in such a manner that the lighter items are ejected from the material on the per- forated conveyor.

This device is effective in sorting especially plastic or other larger lighter objects away from the material stream. The device however requires more space than a wind sifter, and is therefore less suitable to be used with the method when the apparatus for carrying out the method is arranged on a mobile unit, where space and efficiency is at a premium. For stationary plants the laser optics/perforated conveyor option is a viable option. A suitable device is available from for example www.Titech.de In a further advantageous embodiment the method is further distinguished in that after step b) a second wind sifter is arranged wherein the cleaned material leaving the cleaning unit is introduced into the second wind sifter, where a second upwards airflow, said second upwards airflow being slower than the first upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said second wind sifter, where the paper and any heavier particles are extracted as a third fraction from the second wind sifter.

The airflow in the wind sifters may be recirculated, such that an equilibrium in the airflow either for each wind sifter or for the pair of wind sifters is achieved.

In a further advantageous embodiment of the method it is foreseen that between method steps a) and b), i.e. the first and second wind sifters, dust and smaller particles are removed from the second fraction. In connection with the inventive method it is desired to remove dust as early in the treatment as possible in that the dust may clog up further parts of the procedure and furthermore dust is not suitable to be reused, and particularly not when the paper fraction is the desired recyclable, valued waste stream. Furthermore the means for removing the dust and the smaller particles is in the shape of air-locks, which in fact are slowly rotating valves. The air locks between the first and second wind sifters are advantageously arranged as the upper limitation of the second wind sifter and in this manner also helps to distribute the material to be treated in the second wind sifter, substantially evenly across the wind sifters cross section. In this manner the features of the wind sifter are utilised in the best manner.

In a still further advantageous embodiment of the invention the combined material to be treated according to the method is received in a material distribution unit, from which the combined material is dosed and fed to the first wind sifter. In this connection the term dosed shall be understood as the material distribution unit regulates how much material is allowed to enter the first wind sifter, i.e the material distributing unit is dosing the amount of material according to the wind sifters and other downstream equipments' capacity/ability to correctly treat the combined materi- al.

The material distribution unit has two main purposes, namely to translate batch feeding of a combined material being fed into the material distribution unit into a continuous flow of material from the material distribution unit and to provide and control the flow capacity of the feed material such that the further process steps, for example the wind sifters etc., downstream of the material distribution unit are provided with material as a continuous drizzle of material being entered into the first wind sifter.

One of the overriding aspects of the invention, especially during the development of the method and apparatus is the possibility for the method to be carried out at the site where the combined material to be treated is located, where the wind sifters, conveying means, cleaning unit, dust removal means, material distribution means and other necessary aggregates necessary for carrying out the method are arranged on a mobile unit, which unit is transported to the site where the combined material is to be treated or is stored.

In order to have a functioning plant on a mobile unit, which is able to handle this type of combined waste/reusable material at large quantities, rapid handling and under strict environmental conditions, the requirements to the method and apparatus are very high. Selecting the wind sifters in combination with the material hopper is done in order to address the special requirements as to space and through-put. The selection of wind sifters is particularly important on mobile units as the space requirement is relatively limited whereas it is possible to encapsulate the separation process and maintain a rather high output.

The invention is also directed to an apparatus for separating fractions from a combined material, said combined material at least comprising paper and gypsum, where said apparatus comprises: - means for receiving and feeding the combined material to a

- first windsifter, said wind sifter having an upper inlet and upper and lower outlets;

- first conveying means connecting said upper outlet of said first wind sifter to a

- cleaning unit at least comprising a sieve and having means for mechanically impact- ing and cleaning the material feed to said cleaning unit, where said cleaning unit has at least two outlets: a first outlet allowing gypsum and debris to evacuate the cleaning unit, and a second outlet allowing cleaned paper to evacuate the cleaning unit.

The receiving and feeding means make sure that the combined material is fed as a substantially continuous drizzle to the first wind sifter where the first separation of material is achieved. This continuous drizzle of material provides for the downstream processes to be carried out substantially continuous. As already explained above the wind sifter and particularly the air speed inside the wind sifter is adjusted such that heavy particles, for example lumps of gypsum, steel and other materials, will move against the airflow due to the influence of gravity and be evacuated through the outlet at the bottom of the first wind sifter.

This fraction of the material may be treated again before being entered into the means for receiving and feeding the combined material, for example in a crushing unit such that the particles of this fraction become smaller. The fraction which is lifted by the airflow inside the wind sifter is transported to the second wind sifter by conveying means. Typically, the conveying means will be in the shape of a pipe conveyor such that any dust or lighter fractions are not able to escape to the ambient environment, and furthermore all the material will be transported in the pipe due to an airflow inside the pipe and enter the second wind sifter in an upper part of the wind sifter.

Further advantageous embodiments are defined in the sub claims where the apparatus is defined in various embodiments as having: - a second wind sifter is arranged downstream of the first conveying means, said second wind sifter having an upper inlet connected to said first conveying means and upper and lower outlets, where said lower outlet by one or more second conveying means is connected to said cleaning unit. the first wind sifter is replaced by a device for sorting lighter items from the material, where said device comprises optical recognition means, particularly a laser and a perforated conveyor on which the material is transported, where air-jets are arranged below said perforated conveyor such that as the optical recognition means detects lighter items in the material, the air-jets are activated in such a manner that the lighter items are ejected from the material on the perforated conveyor. said cleaning unit a second wind sifter is arranged wherein the cleaned material leaving the cleaning unit is introduced into the second wind sifter, where a second upwards airflow, said second upwards airflow being slower than the first upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said second wind sifter, where the paper and any heavier particles are extracted as a third fraction from the second wind sifter. the means for receiving and feeding the combined material to the first wind sifter, comprises a hopper for receiving material to be treated in the apparatus, where in the bottom of said hopper a conveyor is arranged for urging the received combined material against a distribution device, said distribution device arranged such that a lower part of the device is distanced a predetermined distance above the conveyor, and that the device is rotating such that the lower portion of the device is rotating against the flow of material on the conveyor, whereby a predetermined amount of material is allowed to pass the distribution device. The object of the means for receiving and feeding the combined material to the first wind sifter is to make sure that a substantially continuous drizzle of material is fed into the first wind sifter, such that a substantially continuous separation process is obtained by the apparatus. Usually materials to be treated by the apparatus according to the invention will be provided in batch form, i.e. will be dumped into a hopper. It is therefore the receiving and feeding mean's task to make sure that a continuous drizzle is achieved. This may be achieved in a number of ways, but it has been found advantageous to arrange a conveyor at the bottom of a hopper such that any material dumped in the hopper will be transported by the conveyor. Downstream of the conveyor (still in the hopper) is arranged a distribution device which due to its rotation against the material being transported on the conveyor, will only allow a certain amount of material to pass on to the wind sifter. The distribution device may be a large drum provided with teeth or the like on the outside. The drum is brought to rotate around an axle arranged perpendicular to the materials travelling direction, and at a distance from the conveyor, leaving a gap between the conveyor and the lowermost part of the drum, through which material may pass on to the wind sifter. Surplus material will be removed by the drum and replaced back on the material in the hopper upstream from the drum. In this manner a substantially continuous material flow is conveyed to the first wind sifter. By adjusting the speed of the conveyor, the height of the gap and/or the working speed of the distribution device the drizzle of material may be controlled. the first and/or second wind sifters are provided with dust separators which separators are connected to dust filters, where said filters comprises means for collecting gypsum dust. the cleaning unit comprises a rotatable drum sieve wherein brushes and/or baffles are arranged, such that the brushes and/or baffles will engage and/or impact the fraction of the combined material fed into the cleaning device. the conveying means between the first and second wind sifters, and/or between the first wind sifter and the cleaning unit, and/or between the cleaning unit and the second wind sifter, and/or between the second wind sifter and the cleaning unit, and/or between the device for sorting lighter items and the cleaning unit one or more restriction or impact chicanes are arranged for impacting material being passed through the conveyor. The restriction or impact chicane serves to loosen or segregate materials from each other being transported in the conveyor from the first to the second wind sifter. The impact chicanes or further chicanes may be incorporated in the materials flow path through the process, with similar effect. - the apparatus is a mobile unit, where all means, wind sifters, features and aggregates are arranged on a mobile unit which unit optionally is self-sufficient with regard to power. In a still further advantageous embodiment of the invention the first and second wind sifters are provided with dust separators which separators are connected to dust filters, where said filters comprises means for collecting gypsum dust.

The removal of dust and collection in a dust filter provides the advantage that the ap- paratus as such does not have a huge impact on the environment in that the dust is kept in a closed system and collected. Furthermore, as the dust is removed from the material being transported through the various devices of the apparatus, this dust fraction need not be treated in the various devices and as such the overall amount of material being moved through the apparatus is limited to the necessary and valuable frac- tions by removing undesired dust etc.

Furthermore the dust removal and separating units arranged between the first and second wind sifters also distributes the material in the second wind sifter, whereby the second wind sifter achieves an optimum performance, as the material introduced is introduced substantially evenly across the entire cross-section of the wind sifter. For this purpose one or more dust separators may be arranged in the inlet of the second wind sifter.

Another important feature of the invention is the cleaning unit which comprises a ro- tatable drum sieve wherein brushes and/or baffles are arranged, such that as the drum rotates the brushes and/or baffles will engage or impact the fraction of the combined material fed into the cleaning device.

By the time the material reaches the cleaning unit, a substantial segregation and sort- ing has been carried out, and the material which will typically enter the cleaning unit, will be relatively dust free and will be in the shape of relatively clean paper, paper with an adhered material layer and agglomerates of other substances. By the mechanical impact, particularly with brushes against the paper, and the baffles impacting the paper, the material adhered to the paper will be worn or brushed off or due to the im- pact with the baffles be knocked off the paper such that the paper will be very clean from material when it exits the cleaning unit.

The drum rotates slowly in order to clean the apertures in the drum from material resi- due removed from the paper by the brushes and baffles. Naturally the brushes and/or baffles may also rotate, typically counter rotate relative to the drum. The rotation speed may furthermore be varied in order to optimize the effect.

Further details of the apparatus will be described with reference to a detailed descrip- tion of an apparatus according to the invention described with reference to the accompanying drawing.

Description of the Drawing

The invention will now be explained with reference to the accompanying drawings in which

Figure 1 illustrates a schematic overview of the various steps and devices;

Figure 2 illustrates a mobile unit carrying out the separating process.

Detailed Description of the Invention

In figure 1 is illustrated a schematic overview of the various steps and devices which together make up the inventive method and apparatus.

Initially, material to be treated is loaded into the means for receiving and feeding the combined material, in this instance in the shape of a hopper 10. At the bottom of the hopper 10 is provided a conveyor belt 11 which will transport the combined material towards a distribution device 12. As the combined material is loaded into the hopper 10 the conveyor belt 11 will urge the material against the distribution device 12 such that the material which is let out of the hopper 10 onto the conveyor will be provided as a substantially continuous material stream. Due to the conveyor 11 continuously urging the material against the distribution device 12 a drizzle of shredded and/or particulated and/or impacted material will substantially continuously arrive at the conveyor 13. The conveyor will by further conveying means 14 introduce the drizzle of material into a first wind sifter 20. The fur- ther conveying means 14 may comprise an air lock such that any dust generated from this stage forward will be contained inside the further processing equipment.

The first wind sifter is provided with a housing inside of which an upwards airflow is arranged such that particles being introduced through the air lock will, depending on their weight either be urged upwards due to the airstream inside the wind sifter 20 and the heavier particles which due to the influence of gravity will be able to counter the upwards airflow will fall to the bottom of the wind sifter 20. During the passage through the wind sifter 20 the downwards travelling particles will encounter baffles 21, 22. As the material pieces encounter the baffles 21, 22, the impact will cause further disintegration of the material such that potentially lighter particles liberated by the impact will be carried by the upwards airstream out of the outlet 23 provided in the wind sifter 20.

The wind sifters, both the first and the second wind sifters 20, 30 may have a zig-zag shape such that the air-flow cross-section is relatively constant, but due to the zig-zag shape the material being introduced into the wind sifters will experience mechanical abrasion or impact through the passage in the wind sifters.

The wind sifters 20, 30 may have baffles or zig-zag configuration or both depending on the particular application.

Eventually the heavier particles which are able to overcome the airflow due to the influence of gravity will end up in the bottom of the wind sifter 20 and be evacuated onto a further conveyor 24 and a collection point 25. The material arriving at the collection point 25 may be any type of material such as for example wood, plastic, steel, glass, but also lumps of combined material which has not been crushed or otherwise fractioned sufficiently in order to be able to be carried out of the first wind sifter by the upwards airstream. Therefore, in some examples the material collected at the collection point 25 may be reintroduced into the hopper 10 for a reprocessing cyclus as described above. The material being evacuated through the upper outlet 23 will be transported to a second wind sifter 30 by means of appropriate conveying means 26. Typically, these conveying means will be pipes in which an air-flow will convey the material from the first wind sifter 20 to the second wind sifter 30. Also in these conveying means appro- priate air locks 27, 28 are provided. The air locks 27, 28 as well as the air lock in the conveying means between the conveyor 13 and the first wind sifter also has means for separating the dust from the air-flow.

In the second wind sifter 30 a second upwards air-flow is provided such that lighter items will be extracted through the upper outlet 31 whereas heavy items which due to the impact of gravity will be able to overcome the outwards air-flow will be extracted through the lower outlet 32. The lower outlet 32 is connected to conveying means 33 which will lead the collected heavier fraction evacuated through the lower outlet 32 to a cleaning unit 40.

The conveying means 33 may be provided in any suitable manner, but preferably either a pipe system conveyor or an air-flow transports the fractions from the second wind sifter 30 to the cleaning device 40 or a series of conveyors may be provided according to circumstances.

The cleaning device typically will comprise a rotating sieve 41 such that the fraction of the combined material arriving in the cleaning device will be rotated by the sieve thereby impacting with other material parts as well as the sieve and in that process liberate particles adhered to the paper. Also a brush and/or baffle device may be in- stalled inside the cleaning device 40 in order to mechanically brush off or knock off any adhered or loosely held particles from the paper or cardboard fractions. The brush and/or baffles may also be rotated optionally in a direction opposite to that of the drum. The drum is mainly rotated in order to clean the openings in the sieve, thereby allowing loosened material to escape the sieve. The particles will due to gravity and the apertures in the sieve 41 be able to collect at the bottom of the cleaning device 40 and be evacuated through a bottom outlet 42 for further processing or storage in a receiving unit 43. Typically, the material arriving at the receiving unit 43 will consist of powder, sand and paper fibres. Although a rotating drum sieve is described a flat sieve being agitated and having means for brushing and/or impacting the material is also suitable within the concept of the present invention. The remaining fractions, i.e. the cleaned paper fractions will be evacuated from the cleaning device 40 and by suitable conveying means collected in bulk 45 for reuse.

The cleaning device, or rather the housing of the cleaning device is also connected to a filter and a suction fan, such that dust or lighter particles present in the cleaning device may be evacuated by these means.

In this manner a combined material is introduced into the hopper 10 and by means of the various processes and devices described above will be mechanically separated in a dry process such that a valuable waste fraction, i.e. the cleaned paper, will be collected at the end.

During the process air locks and dust separators generally referred to by the letter A are arranged in order to collect any dust generated due to the processing of the combined material. This collection may be done in order to purify the separation process, but also in order to collect valuable fractions, for example gypsum powder or combined gypsum powder with paper fibres which may be used as additives in other processes, for example the manufacture of gypsum boards or the like.

In this embodiment of the invention illustrated with reference to figure 1 a restrictor or impact chicane 50 is arranged between the first and second wind sifters 20, 30. This chicane serves to further allow the particles evacuated by the upper outlet 23 of the first chicane 20 to be mechanically abrased in order to loosen and separate particles from the paper. Consequently, these loosened particles will either be removed due to the dust filters/separator A, 27, 28 or be evacuated through the upper outlet 31 in the second wind sifter 30.

Impact restrictors or chicanes may be arranged in any suitable positions, especially immediately prior to the material entering the cleaning device, a restrictor or chicane is advantageous. Turning to figure 2 an illustration of a mobile unit carrying out the separating process as described above is illustrated. The mobile unit 60 is arranged on a trailer 61 said trailer having connection means to a truck 64 and a set of bogey wheels 66 in this par- ticular embodiment. The hopper 10 is in this embodiment provided on legs 16 such that it will be possible to feed a drizzle of material arriving to the mobile unit 60 by the conveyor 13 into a relatively elevated receiving hopper 68 arranged in combination with the first air lock A on the mobile unit. The features mentioned above are provided with the same reference numbers in figure 2 as in figure 1 so that the only difference between figure 1 and figure 2 is that figure 1 schematically illustrates the process and the various devices used in the inventive method whereas figure 2 illustrates a mobile unit onto which the various devices have been fitted. In this context it should be noted that the mobile unit may be provided with a housing covering the various implements, but for clarity reasons this housing has not been illustrated.

Furthermore in the illustration the mobile unit has been prepared for production in that a number of the features of the apparatus have been "unfolded" i.e. brought from their transport position to their production position. In the transport position, the features are arranged on the vehicle in the most optimized manner with respect to transport (i.e. limited width and height). In this position the apparatus is not suitable to function, as for example many of the conveyors will not be able to transport material to desired locations. The features/aggregates which are to be repositioned when making the mo- bile unit ready for production or ready for transport are mounted/arranged such that they can easily be swung into position, for example by means of actuators etc.

Eventually the cleaned paper fraction will be delivered from the mobile device 60 by the conveyor 44 for further collection.

Turning shortly back to figure 1 the various air locks 27, 28, A and dust separators are connected to dust filter units 70, 72, 74 which in turn are provided with appropriate suction fan means 76, 78, 80 such that substantially clean and dust free air may be expelled from the process equipment whereas the dust is collected by the dust filters 70, 72, 74 for example for further use or for appropriate disposal.

The cleaning device is here described as comprising a rotating sieve 41, but the me- chanical cleaning device may also have other configurations as long as for example it is ensured that the paper pieces arriving at the cleaning unit are mechanically abraded, for example by brushes, sponges, impact baffles or the like which are effective to brush off or remove any particles adhered to the paper's surface.

Claims

1. Method for separating a combined material where said material at least comprises gypsum and paper, where said combined material a) is led into a first wind sifter in which wind sifter a first upwards airflow is regulated such that a first fraction comprising heavier particles of the material falls to the bottom of the wind sifter and are evacuated through a bottom outlet, whereas a second fraction comprising lighter particles and paper is evacuated through an upper outlet; and b) where the lighter particles and the paper evacuated through the upper outlet is led into a cleaning unit, in which unit at least the paper is mechanically cleaned from any loose or adhering particles, gypsum or other matter, after which cleaning process the cleaned paper is transferred to further processing, and the loose or adhering particles, gypsum or other matter, as well as any heavier particles are collected separately.

2. Method for separating a combined material according to claim 1 where said material at least comprises gypsum and paper, where after step a) a second wind sifter is introduced wherein the second fraction (evacuated from the upper outlet) is introduced into said second wind sifter, where a second upwards airflow, said second upwards airflow being slower than the first upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said second wind sifter, where the paper and any heavier particles are extracted as a third fraction from a bottom outlet of the second wind sifter, and transferred to the cleaning unit in step c).

3. Method for separating a combined material according to claim 1 wherein the first wind sifter is replaced by a device for sorting lighter items from the material, where said device comprises optical recognition means, particularly a laser and a perforated conveyor on which the material is transported, where air-jets are arranged below said perforated conveyor such that as the optical recognition means detects lighter items in the material, the air-jets are activated in such a manner that the lighter items are ejected from the material on the perforated conveyor.

4. Method for separating a combined material according to claim 1 wherein after step b) a third wind sifter is arranged wherein the cleaned material leaving the cleaning unit is introduced into the third wind sifter, where a third upwards airflow, said third upwards airflow being slower than the first upwards airflow and slower or equal to the second upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said third wind sifter, where the paper and any heavier particles are extracted as a third fraction from a bottom outlet of said third wind sifter.

5. Method according to claim 4 wherein the second wind sifter is connected to the cleaning unit, such that the second wind sifter also functions/replaces the third wind sifter.

6. Method according to claim 2, 3 or 4, wherein between the first and second wind sifters, dust is removed from the second fraction.

7. Method according to any preceding claim wherein the combined material to be treated according to the method is received in a material distribution unit, from which the combined material is dosed and fed to the first wind sifter.

8. Method according to any preceding claim wherein the method is carried out at the site where the combined material to be treated is located, where the wind sifters, conveying means, cleaning unit, dust removal means, material distribution means and other necessary aggregates necessary for carrying out the method are arranged on a mobile unit, which unit is transported to the site where the combined material is to be treated or is stored.

9. Apparatus for separating fractions from a combined material, said combined material at least comprising paper and gypsum, where said apparatus comprises:

- means for receiving and feeding the combined material to a

- first windsifter, said windsifter having an upper inlet and upper and lower outlets;

- first conveying means connecting said upper outlet of said first windsifter to a

- a cleaning unit at least comprising a sieve and having means for mechanically impacting and cleaning the material fed to said cleaning unit, where said cleaning unit has at least two outlets: a first outlet allowing gypsum and debris to evacuate the cleaning unit, and a second outlet allowing cleaned paper to evacuate the cleaning unit.

10. Apparatus for separating fractions from a combined material according to claim 9 wherein a second wind sifter is arranged downstream of the first conveying means, said second wind sifter having an upper inlet connected to said first conveying means and upper and lower outlets, where said lower outlet by one or more second conveying means is connected to said cleaning unit.

11. Apparatus for separating a combined material according to claim 9 wherein the first wind sifter is replaced by a device for sorting lighter items from the material, where said device comprises optical recognition means, particularly a laser and a perforated conveyor on which the material is transported, where air-jets are arranged below said perforated conveyor such that as the optical recognition means detects lighter items in the material, the air-jets are activated in such a manner that the lighter items are ejected from the material on the perforated conveyor.

12. Apparatus according to claim 9 where downstream from said cleaning unit a third wind sifter is arranged wherein the cleaned material leaving the cleaning unit is intro- duced into the third wind sifter, where a third upwards airflow, said third upwards airflow being slower than the first and/or second upwards airflow, is regulated such that paper and any heavier particles fall to the bottom of said third wind sifter, where the paper and any heavier particles are extracted as a third fraction from the third wind sifter.

13. Apparatus according to claim 9, wherein the means for receiving and feeding the combined material to the first wind sifter, comprises a hopper for receiving material to be treated in the apparatus, where in the bottom of said hopper a conveyor is arranged for urging the received combined material against a distribution device, said distribu- tion device arranged such that a lower part of the device is distanced a predetermined distance above the conveyor, and that the device is rotating such that the lower portion of the device is rotating against the flow of material on the conveyor, whereby a predetermined amount of material is allowed to pass the distribution device.

14. Apparatus according to claims 9 or 12 wherein the first and/or second and/or third wind sifters are provided with dust separators which separators are connected to dust filters, where said filters comprises means for collecting gypsum dust.

15. Apparatus according to any of claims 9 to 14 wherein the cleaning unit comprises a rotatable drum sieve wherein brushes and/or baffles are arranged, such that the brushes and/or baffles will engage and/or impact the fraction of the combined material fed into the cleaning device.

16. Apparatus according to any preceding claim, wherein in the conveying means between the first and second wind sifters, and/or between the first wind sifter and the cleaning unit, and/or between the cleaning unit and the second wind sifter, and/or between the second wind sifter and the cleaning unit, and/or between the device for sorting lighter items and the cleaning unit, one or more restriction or impact chicanes are arranged for impacting material being passed through the conveyor.

17. Apparatus according to any preceding claim, wherein in the first wind sifter and/or the second wind sifter and/or the third wind sifter, one or more baffles or impact chicanes are arranged for impacting material being passed through the first wind sifter and/or the second wind sifter and/or the third wind sifter.

18. Apparatus according to any of claims 9 to 17 wherein the apparatus is a mobile unit, where all means, wind sifters, features and aggregates are arranged on a mobile unit which unit optionally is self-sufficient with regard to power.