The present invention relates to a method and plant for separation of composed materials, preferably waste construction materials.

Especially in connection with construction projects, such as remodelling and demolition of buildings, large quantities of composed waste materials often occur, some of which are combustible and some which are not. Especially the materials composed of combustible and non-combustible materials entail large quantities of waste which as a rule must be hauled to controlled disposal sites. This entails transportation costs and waste management fees. In the following, reference is made to plasterboards as the composed material which is to be separated, but it is underlined that also the processing of other types of composed waste materials can occur; materials which are to be separated to such a degree that the amount of waste material to be deposited after the separation is minimal or not requiring disposal at all as the recovered product will be so pure that it can be recycled.

In connection with remodelling and demolition interior walls and ceilings covered by the well-known plasterboards are broken down, resulting in large quantities of waste as the knocked-down plasterboards contain large quantities of gypsum and cardboard adhering to the gypsum.

From US 5 100 063 a method for separation and processing composed waste construction materials, for example plasterboard, is known. This method includes the following steps: -shredding of the composed material -feeding of the composed material into a crusher where it is wrenched and rolled -screening of the crushed material, and - conveying the separated fractions to bins, heaps or

containers for collection.

From the aforementioned patent a plant for separating and recycling of composed materials is also known. The plant includes a shredder, a crusher/roller unit, which receives the shredded material from the shredder, a first conveyor station for conveying the material to a screen which separates cardboard and gypsum, and a number of additional conveyor stations for further conveying of the separated sub- fractions (cardboard and gypsum) for further processing and/or heaps, bins or containers.

The aforementioned plant is suitable for separating gypsum and paper from knocked-down waste plasterboards, and there is no hindrance that the gypsum from the aforementioned boards can be recycled and processed to new plasterboards.

However, recycling requires that gypsum and cardboard in the waste plasterboards are totally separated from each other, which contrary to expectations is not always the case in spite of the fact that the materials have been shredded and subsequently crushed/rolled. Furthermore, recycling requires that other sub-fractions of construction waste, if any, are totally removed from the gypsum. The aforementioned other sub-fractions may include for example metallic parts such as metal profiles or parts hereof from the plasterboard framework, other kinds of fixtures for the fixing of the plasterboards to the structural parts, or nails, screws and metallic parts of this kind which have been used for mounting purposes on the wall side of the boards.

Therefore, the present invention is directed to a method for the efficient separation and reprocessing of composed materials, preferably waste construction materials for example knocked-down plasterboards, which ensures the removal of the metal fractions from these materials, and a plant for performing the method which also ensures an efficient separation of gypsum and cardboard from plasterboards.

A suitable method for separation and reprocessing of composed materials, preferably waste construction materials, includes the following steps ; a) -shredding of the composed material<BR> b) -feeding the shredded material into a roller/wrenching unit, c) -screening the shredded and crushed material in a screen in order to separate the sub-components in the composed material, d) -transport of the separated sub-components to bins, heaps, containers being characterised in that between process steps b) and c) the first segregation of metallic parts in the crushed material is carried out in a magnet separator.

The advantage of this being that immediately after shredding and crushing of the material a segregation of metallic parts, if any, is carried out, before the crushed material is screened in order to separate the sub-fractions in the composed material, which ensures that the screen is not clogged by the metallic parts in question and there is no wear and tear on the screen from these metallic parts.

Therefore the metallic parts are removed from the sub- fractions into which the material is separated in the screen.

When reprocessing plasterboard according to this method the sub-fractions which result from the screening, namely cardboard and gypsum, are essentially free from metal, which means that the gypsum fraction can be recycled in the production of new plasterboards and the paper fraction can be pressed, combusted or recycled.

However, tests carried out with the method forming the subject of the present invention have shown that the fractions after screening may contain further metallic parts which have not been removed in the process in the first magnet separator, which means that the sub-fractions cannot

be considered pure recycling materials which can be used directly without further processing.

In order to ensure an approximately 100% removal of metallic parts from the sub-fractions, another segregation of metal can be carried out in a second magnet separator between process steps c) and d) for one or more of the separated sub- fractions.

The method forming the subject of the present invention is especially suitable for separation of waste plasterboards where the roller/wrenching unit ensures an efficient separation of cardboard from the adherent gypsum. As the presence of metals in the materials will reduce the efficiency of the screening, a first segregation of metals is therefore carried out before the material crushed in the roller/wrenching unit is conveyed to the screen. The screening ensures a separation into mainly a cardboard fraction and a gypsum fraction of the crushed but mixed materials. And as the recycling of the gypsum requires that the gypsum is 100% pure and free from other occurring materials such as metal, this fraction is therefore submitted to a second segregation of metal so that the gypsum material that is subsequently transported to a heap, bin, container or the like is metal-free.

Of course some of the fractions may be submitted to other separation processes, for example it will be possible to remove contents of plastics, if any, from the cardboard fraction to enable the recycling of the cardboard fraction in industrial composting or for paper pulp.

In order to obtain a volume reduction of the bulky sub- fraction parts of the composed material, a compression of one or more of these fractions can be carried out as stated in claim 3.

In the reprocessing of waste plasterboard it is therefore accomplished through compression that the cardboard fraction

can be used as fuel briquettes. Further the compression entails a reduced transport volume of this fraction. Also contents of plastic, if any, segregated from the cardboard section may be compressed.

A plant for the performance of the method according to claim 1 is embodied in claim 4, featuring a shredder, a roller/wrenching unit that receives and processes the shredded material from the shredder, a conveyor station for conveying the material from the roller/wrenching unit to a drum screen contained in the plant for separation of the composed material in at least two sub-fractions, and a number of conveyor stations according to the number of sub-fractions for conveying the sub-fractions to further processing and/or to heaps, bins, containers or the like, and being characterised in that the plant between the roller/wrenching unit and the drum screen also features a conveyor station for conveying the crushed composed material to a first magnet separator, a second conveyor station for the carrying away of the segregated metal to a heap or a container.

A plant for the performance of the method according to claim 2 is embodied in claim 5, featuring a shredder, a roller/wrenching unit that receives and processes the shredded material from the shredder, a conveyor station for conveying the material from the roller/wrenching unit to a drum screen contained in the plant for the separation of the composed material into at least two sub-fractions, and a number of conveyor stations according to the number of sub- fractions for conveying the sub-fractions to further processing and/or to heaps, bins, containers or the like, and being characterised in that the plant between the roller/wrenching unit and the drum screen also features a conveyor station for conveying the crushed composed material to a first magnet separator, a second conveyor station for the carrying away of the segregated metal to a first heap or container for metallic parts and that the plant further features a second magnet separator for the processing of at

least one of the sub-fractions of the composed material from the drum screen, from which the segregated metal via a fourth conveyor station is transported to the second heap, bin, container or the like for metallic parts, and a fifth conveyor station for conveying the metal-free sub-fraction of the composed material to a heap, bin, container or the like.

So after processing plasterboards in this plant in which the separated gypsum is subjected to a second magnet separation for the segregation of metallic parts, if any, that have not been removed in the first magnet separator, the gypsum will be ready for immediate recycling as a raw material in the production of new plasterboards.

Further the cardboard fraction can be recycled either in industrial composting where the cellulose in the paper is a desired carbon source.

With the intention of releasing the gypsum that contrary to expectation still can adhere to very few of the pieces of cardboard that are fed into the drum screen and which further may contain metallic parts which have not been segregated in the first magnet separator, the drum screen may feature an interior cantilevered roller near the discharge for the cardboard sub-fraction of the drum screen, which in contact with the interior side of the screen and which crushes this gypsum and thereby releases it from the cardboard pieces. In this way a nearly 100% removal of gypsum from the cardboard pieces is obtained and further the metallic parts, if any, in the material crushed by the cantilevered roller in the drum screen, will be segregated when this fraction is processed in the following second magnet separator.

In order to obtain an optimal separation of cardboard and gypsum the rotary speed of the drum screen and/or the inclination of the screen towards the discharge may be adjustable. In this way the preferred flow rate and thus the

preferred processing time of the material in the screen is obtained.

In order to obtain a volume reduction of bulky sub- fractions of the composed material after screening, the plant may feature at least one compression unit for the compression of one or several of the sub-fractions of the composed material screened in the drum screen and in this connection conveyor stations by means of which the compressed material via conveyor stations is transported to heaps, bins, containers or the like.

In this way for example cardboard and paper can be compressed to fuel briquettes which are easier to handle and transport than bulk material of this kind.

In order to be able to segregate also impurities from the sub-fractions, the plant may feature one or more separating units for sorting out materials from one or more sub- fractions with corresponding conveyor stations for the transport of the segregated material and of the pure sub- fraction to heaps, bins, containers or the like.

During the operation of the plant for processing composed materials it will be necessary to carry away the individual sub-fractions that are resulting from the plant in a suitable way. This applies to the smaller fractions but mainly to the fractions with high tonnage. At the same time it will be practically a must that the transport of the sub-fractions to bins, heaps or containers can be carried out without manual work apart from the provision and collection of bins or containers. Especially for the transport of the main sub- fractions several bins or containers will be needed and to avoid periods of idleness it will be necessary that during the operation, material can be transported from the plant to several bins or containers by means of one and the same discharge conveyor which changes the discharge area of the conveyor for example from one container to the next for the same sub-fraction when the first container is full. To this

end the plant forming the subject of the present invention can be designed in such a way that at least one of the conveyor stations conveying one or more sub-fractions of the composed material to heaps, bins, containers or the like is designed as a turnable and tiltable conveyor.

In order to obtain a distribution of the material from the conveyor over the total area of the container/bin without manual labour, the turnable and tiltable conveyor discharges into an essentially horizontal conveyor with a discharge area that is adjustable in the longitudinal direction of the conveyor essentially by means of an actuator.

In this way the material conveyed by the horizontal conveyor can be distributed evenly over the inside area of the container underneath.

In order to control the filling of the container by means of the horizontal conveyor this can be equipped with a sensor for registration of the distance between the level of the discharge of the conveyor and the level of the material discharged by the conveyor in the discharge area.

To obtain full automation of the filling of the bins or the containers, the aforementioned sensor may be connected to a control unit designed in such a way that on the basis of a programmed distance between the level of the discharge of the conveyor and the level of the material discharged by the conveyor in the discharge area and the signals received from the sensor the control unit activates the actuator in order to change the discharge area of the conveyor as soon as the programmed distance is reached.

In order to obtain suitable transport of the separated sub-fractions of the composed material, the conveyor units are preferably designed as screw conveyors and/or belt conveyors.

Further especially the use of screw conveyors ensures that the transport is carried out in a closed space, which is advantageous in relation to the prevention of dust emission from the plant and the use of screw conveyors makes a variable discharge area possible, as the bottom plate of the screw conveyor features an opening which is movable in the longitudinal direction of the conveyor because of the telescopic nature of the said bottom plate.

In order to minimise the transport of the composed materials from the source to the places where the recycled sub-fractions are used, the plant forming the subject of the present invention is mounted on a chassis with wheels.

This gives the advantage of a mobile plant that can be moved to the place of the source of the composed material where the plant is put into operation for processing composed materials into its original sub-fractions. Then the sub- fractions are stored in heaps, bins, containers or the like, and transported directly to the recycling place.

As the components of the plant forming the subject of the present invention are mainly driven by electric motors, operation of the plant will entail a rather high power consumption at the place of operation. When demolition or remodelling works have reached the stage where composed waste materials occur, the power will often have been interrupted leading to an energy supply problem. Further, it is also doubtful whether the necessary power capacity for the operation of the plant is available. In order to ensure that the plant can operate at any location, it will often be an advantage to supply the plant with a generator with sufficient energy capacity for the operation of the plant.

Shredding, rolling/wrenching and screening etc. involves a mechanical impact on the composed, shredded material. This invariably leads to a heavy generation of dust at the plant site and in the vicinity which can be a nuisance to the people living in the area and to people passing by the area of operation. In order to eliminate or reduce the dust emission the plant may be enclosed and feature a suction

device with dust and particle filters at the air discharge.

The filters are counter flushed with compressed air and the filtered out dust is led to the material flow to the drum screen by means of the screw conveyor.

In this way the need for regular emptying/cleaning of the suction device filters and the need to deposit waste from the plant in connection with the operation is eliminated. At the same time all applicable regulations and dust emission limits in connection with demolition works are met.

In order to ensure that there is no dust emission where the shredded, separated material from the essentially horizontal conveyor is filled into for example a container in free fall, the conveyor may be covered in its entire length with dust covers which can be rolled down and which are mounted between the sides of the conveyor and the upper edges of the container.

In this way a marked reduction of the dust emission from this part of the plant is obtained, and if a suction under vacuum is carried out through the magnet separators, an underpressure will be created throughout the conveyor which due to the cover between the conveyor and the container will practically eliminate all dust emission from this part of the plant. The air suction through the magnet separators creates an underpressure in and around the shredder and the conveyor station which are the main dust sources of the plant.

The advantage of using screw conveyors is that the tube- formed channels for these conveyors are also used as suction channels for the suction of air, which is filtered through filters before it is discharged to the open air.

The invention is further described by the drawing: Fig. 1 is a flow chart which schematically shows the part processes of the method for separation and recycling of materials, preferably waste construction materials, forming the subject of the present invention in an embodiment

especially suitable for the processing of knocked-down plasterboards.

Fig. 2 is a schematic side view of a plant for separation and reprocessing of materials, preferably waste construction materials for the performance of the part processes stated in fig. 1., forming the subject of the present invention.

Fig. 3 is a detailed side view of the shredding station of the plant with the roller/wrenching unit forming the subject of the present invention, Fig. 4A is a top view of the basic design of the roller/wrenching unit of the plant forming the subject of the present invention, Fig. 4B is a top view of the shredder according to fig.

4A and Fig. 5 is a side view of the roller/wrenching unit according to fig. 4.

Fig. 1 shows the processes through which a composed material (not shown) is put in connection with separation and reprocessing according to the method forming the subject of the present invention, and reference is also made to fig. 2 which shows the components of a plant for the performance of the method for separation and reprocessing of composed materials, preferably waste construction materials, forming the subject of the present invention.

The material (not shown) is first fed into a shredder 2 in which the material is shredded and immediately afterwards is fed into a roller/wrenching unit 4, compare figs. 3,4A, 4B and 5, in which the shredded material is processed between rollers 100, 102 carried by a chassis 98, with shafts 112, 114, where roller surfaces 104 feature a mutually interactive corrugated surface pattern 106, between which the material is

processed in several ways, namely through normal crushing between the rollers, but because of the surface pattern of the rollers the material is also subjected to wrenching which leads to a separation of the shredded composed material into its original sub-components. Because of the fact that rollers 100,102 are driven at different speeds of rotation, a further squeezing of the shredded material between the rollers is obtained. This squeezing further improves the release of the sub-components of the shredded composed material. As can be seen from fig. 5, the roller/wrenching unit further includes scrapers 108,110 on the underside for scraping off adherent material, if any.

The composed material now processed is fed into a magnet separator 12 via a longitudinal screw conveyor 6 underneath the roller/wrenching unit 4, a transverse screw conveyor and a screw conveyor 10, inclining in the flow direction of the material.

Already at this stage it must be noted that the entire plant 1 in the embodiment shown is assumed to be supplied with electric power from a generator 3 which is part of the plant, but in connection with the energy supply of the plant there will naturally also be facilities for connecting the plant to the normal mains supply.

In the magnet separator 12, which in itself is a magnet separator of a known type, the metal waste is segregated from the material flow of shredded and crushed material and the metal waste is conveyed via a screw conveyor 14 to a heap, bin, container or the like.

The material flow is conveyed further through the plant in an inclined screw conveyor 16 and in an essentially horizontal screw conveyor 18 to a drum screen 20, in which cardboard, paper etc. is separated into one separate sub- fraction and the gypsum into another separate fraction.

Cardboard, paper etc. is carried away in an essentially horizontal screw conveyor 22 and an inclined screw conveyor 24 via a screw press 26 where the cardboard, paper etc. is compressed before it is led to a container 27. The compression may be carried out with such a force that the compressed material can be utilised as fuel briquettes.

The gypsum is transported via the belt conveyor 28, assembling screws 30, an inclined screw conveyor 32 and a horizontal screw conveyor 33 to a second magnet separator 34 for segregation of residual metallic parts, if any, in the gypsum. The segregated waste metal is carried away to a heap, bin or container via a screw conveyor 36.

The gypsum which is now ready for recycling goes to a closed container 50 via a double screw distributor 38, from where the gypsum can be distributed into at least one of two turnable inclined screw conveyors 40 to essentially horizontal conveyor stations 44 carried by swivel derricks 42 including a screw conveyor 45. The conveyor stations 44 are suspended in turnable derricks 42 in such a way that the conveyor stations 44 are turnable around the axis of rotation of the derricks 49 in the place where these are supported by the chassis of the plant 47 at the corners so that the conveyor stations can be turned from filling the first container 50 to filling a second container (not shown) placed in the immediate proximity of the first container and within the radius of action of the conveyor stations. Furthermore the conveyor stations 44 are suspended in such a way on the turnable derricks 42 that the conveyor stations 44 can be inclined as required.

The screw conveyor 45 of the conveyor station 44 features a telescopic bottom 46 so that the discharge area of the screw conveyor 45 is adjustable in essentially the total longitudinal axis of the conveyor. Thus the filling of the container 50 placed underneath the conveyor can be carried out without use of manual labour.

The adjustment of the telescopic bottom 46 of the screw conveyor 45 is controlled by the control unit of the plant (not shown) and for the monitoring of the filling ratio (the level of material in the container 50 in relation to the telescopic bottom 46 of the screw conveyor (45) ) the underside of the screw conveyor 45 features a distance meter 48 for measuring the distance between the level of the conveyor discharge and the level of the material discharged from the conveyor discharge. The distance meter is connected to the control unit of the plant and supplies information about the actual filling level of the container 50 below the position of the actual conveyor discharge area and the control unit is designed to initiate a shift of the conveyor discharge area to an area where the required filling level has not been reached yet when the filling level reaches a pre-programmed distance from the underside of the conveyor 45 to the loaded material, and when the container is full, the screw conveyor is stopped momentarily while by means of the turnable derrick the conveyor is turned to a position over an empty container placed in the proximity of the full one and within the radius of action of the conveyor at the same time as the conveyor station at the opposite side of the chassis is activated and begins to fill the container 50 placed underneath the conveyor discharge area 43.

The horizontal conveyor 45 further features dust covers (not shown) in the total length of the conveyor supported on roller stays parallel to and on either side of the longitudinal axis and discharge area of the conveyor. During the filling of a container placed underneath the conveyor, these covers are rolled out and are placed hanging onto the upper-side edges of the container forming a closed space under the conveyor during the filling of the container which contributes to the fact that the dust emission for example during the loading of crushed gypsum is minimal. The dust emission can be reduced further and practically eliminated through establishing a vacuum below the dust covers which is achieved by means of the suction through magnet separators

12,34. By establishing suction of air through the magnet separators by means of a suction device 54 an underpressure is obtained in and around the shredder 2 and the conveyor station 44, i. e. the main dust sources in the plant.

The suction device 54 features filters (not shown) which are counter flushed with compressed air, and the filtered-out dust is led to the material flow being taken to the drum screen 20 by means of the screw conveyor 18. In this way the need of a regular emptying/cleaning of the suction device 54 filters and the need to deposit waste from the plant in connection with the operation is eliminated. At the same time all applicable regulations and dust emission limits in connection with demolition works are met.

The advantage of using screw conveyors is that the tube formed channels for these conveyors are also used as suction channels for the suction of air, which is filtered through filters before it is discharged to the open air. The dust covers can, however, be suspended in the same way as a sunshade with foldable arms and with tiltable support around a horizontally oriented axis so that the folded out covers can be raised and lowered mechanically/automatically from and to the upper edges of the container.

Thus an extremely efficient plant for separation and reprocessing of composed materials, preferably waste construction materials, is provided which solves both environmental problems in connection with depositing of, for example construction waste, and which enables composed materials, for example plasterboards, which were previously regarded as waste because there was no cost-effective method <BR> <BR> and no equipment for separation of cardboard, gypsum etc. , to be completely separated so that the sub-components of the waste plasterboards, namely gypsum, cardboard, metal, plastics etc. can be totally separated and reprocessed for recycling. Further it will be possible to achieve marked pollution reductions in connection with the transport of the

sub-components to the place of recycling, as the plant is of a mobile design.

Of course the inventor has realised that the plant can have other embodiments than the aforementioned embodiment shown in the drawings. Thus it would be possible to establish another roller/wrenching unit for an additional processing of the shredded material if the composed material makes this necessary and the plant may feature additional screens etc. but this does not change the inventive aspect directed to a method and a plant for the solution of a hitherto unsolved problem, namely for the separation of composed materials in such a way that these basic components can be reprocessed.