FIELD OF THE INVENTION

The present invention relates to a method for producing a reusable gypsum material and more particularly to a method as defined in the preamble of the independent claim 1.

The present invention also relates to an arrangement for making reusable gypsum material and more particularly to an arrangement as defined in the preamble of the independent claim 11.

The preferred embodiments of the method and the arrangement are defined in the dependent claims.

BACKGROUND OF THE INVENTION

The invention relates to the reprocessing of gypsum material obtained as construction waste so that it can be recycled and reused as gypsum material. The gypsum material obtained as construction waste is typically drywalls and pieces of drywalls. Drywalls are panels made of calcium sulphate dihydrate, i.e. gypsum, with or without additives, and typically extruded between thick sheets of paper provided on the back face and on the front face of the drywall. Drywalls are typically used in the construction of interior walls and ceilings.

The construction waste includes many kinds of material including drywalls containing gypsum. Because construction waste is a mixture of different materials, it often takes too long to separate the material to be useful. In prior art solutions, when reprocessing drywalls, the paper cannot be removed from the surfaces of the drywalls, but the drywalls are crushed as such, whereby the paper is part of the drywall crush. After that the paper is difficult to completely remove from the gypsum.

One of the problems associated with the prior art is that impurities such as paper, cannot be effectively removed from the gypsum material.

BRIEF DESCRIPTION OF THE INVENTION

An object of the present invention is to provide an effective way to produce reusable gypsum material from construction waste containing gypsum waste so that the production of reusable gypsum material does not require a separate line for it and can be operated by only one or two persons. An object of the present invention is also to provide an effective way to produce reusable gypsum material from gypsum waste that is to be treated as mixed construction waste and not just gypsum waste.

The objects of the invention are achieved by a method and an arrangement which are characterized by what is stated in the independent claims. The preferred embodiments of the invention are disclosed in the dependent claims.

The invention is based on the idea of treating the construction waste in successive phases of separating the waste and cleaning the waste.

Method for producing a reusable gypsum material from a construction waste material comprising gypsum waste according to the invention comprises the following steps: a) simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1- 50 mm for providing a separated gypsum material from the gypsum waste; and b] cleaning the separated gypsum material by removing impurity particles from the separated gypsum material for providing the reusable gypsum material from the separated gypsum material.

In the step of simultaneously removing paper material from the gypsum waste and crushing the gypsum waste, the separated gypsum material obtained from the step is in the final grain size without the paper material so that it is after a single phase already ready for final cleaning. The grain size can also be preferably of 0.1 - 40 mm, or 0.1 - 30 mm, or 0.1 - 20 mm. The advantage of the simultaneous separation and crushing is that the process is effective and can be implemented without complex process lines.

The step of simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1-50mm for providing a separated gypsum material from the gypsum waste means that: the gypsum waste is processed in such a way that at the same time as the paper material separates from the gypsum waste, the gypsum of the gypsum waste is crushed into smaller gypsum material particles due to properties of gypsum such as friability or fragility when subjected to impact or other tearing or abrasive movement. This means that while the paper material separates from the gypsum waste, the gypsum in the gypsum waste is crushed. This happens especially when gypsum waste is processed in a device with a surface that tears the paper material away from the gypsum and causes the gypsum to break into pieces. Simultaneously meaning in this context at the same time. This means that as the device tears the paper material away from the gypsum waste, the gypsum is crushed at the same time. The size of the grain of the gypsum depends on the device that is used for performing the step. According to the invention the method comprises: performing the step a) in one device such that removing paper material from the gypsum waste and crushing the gypsum waste is performed in a same process step in the one device. The one device therefore removes the paper material from the gypsum waste and crushes the gypsum waste preferably into the final grain size such that in the next phase the separated gypsum material is already in the final grain size.

According to the invention in the method the step b] comprises removing impurity particles with a screen for dividing the separated gypsum material into reusable gypsum material and impurity particles. The crushed separated gypsum material which is in final grain size is screened such that the impurity particles of for example wool, glass, wood, plastic, metal, brick, concrete are removed from the gypsum material for obtaining reusable gypsum material. Additionally, or alternatively, the step b] comprises removing impurity particles with a magnet for dividing the separated gypsum material into reusable gypsum material and impurity particles which the impurity particles are metallic particles.

According to the invention in the method the step b] comprises removing impurity particles in a first cleaning step, in which the method comprises dividing the separated gypsum material according to particle size such that impurity particles with larger particle size are separated from the separated gypsum material in the first cleaning step to obtain reusable precleaned gypsum material.

Dividing the separated gypsum material according to the particle size means preferably supplying the separated gypsum material through a screen having a mesh which screens the separated gypsum material such that the impurity particles having larger particle size remain on the mesh while the reusable precleaned gypsum material goes through the mesh. The mesh has a mesh size between 1-50 mm, preferably 1 - 20 mm, more preferably 2-15 mm and most preferably 3-10 mm. The reusable precleaned gypsum material that is obtained in the first cleaning step is the reusable gypsum material when no further cleaning is required.

According to the invention in the method the step b] comprises removing impurity particles in a second cleaning step, in which the method comprises dividing the separated gypsum material according to weight such that the impurity particles which are heavier than gypsum material are separated from the separated gypsum material in the second cleaning step to obtain a reusable cleaned gypsum material.

Dividing the separated gypsum material according to the weight means preferably supplying the separated gypsum material to be treated with air such that moving air blows the lighter gypsum material away from the heavier impurity particles. In other words, the separated gypsum material is divided with the help of air flow into lighter fraction which is gypsum material and heavier fraction which is the impurity particles. This way for example glass particles are removed from the separated gypsum material. Depending on the properties of the impurity particles, the moving air can be adjusted to the desired speed. The moving air is the same as an air flow. In other words, the method comprising the step of dividing the separated gypsum material according to weight such that the impurity particles which are heavier than gypsum material are separated from the separated gypsum material in the second cleaning step to obtain a reusable cleaned gypsum material, can further comprise a step of supplying an air flow to the separated gypsum material, and further a step of adjusting the speed of the air flow. The speed can be adjusted based on the properties of the impurity particles for example.

The reusable precleaned gypsum material that is obtained in the second cleaning step can the reusable gypsum material when no other cleaning is required.

According to the invention the method comprises performing the first cleaning step and the second cleaning step successively such that the first cleaning step is performed before the second cleaning step.

This means that the method comprises dividing the separated gypsum material according to the particle size such that impurity particles with larger particle size are separated from the separated gypsum material in the first cleaning step to obtain reusable precleaned gypsum material, and the reusable precleaned gypsum material is further divided according to the weight such that the impurity particles which are heavier than gypsum material are separated from the reusable precleaned gypsum material in the second cleaning step to obtain a reusable cleaned gypsum material which is the reusable gypsum material.

According to the invention the method comprises performing the first cleaning step and the second cleaning step in different devices.

According to the invention the method comprises performing the first cleaning step in a drum screen or in a vibrating screen.

According to the invention the method comprises performing the second cleaning step in a wind shifter.

According to the invention the method comprises performing the step a) in a screening bucket which is arranged to tear the paper material from the gypsum waste simultaneously as the gypsum waste is crushed to provide crushed separated gypsum material.

According to the invention the method comprises performing the step a) in the screening bucket and performing the step b] in a drum screen which are connected one on top of the other in such a way that the gypsum from the screening bucket moves directly to the drum screen. According to the invention the method further comprises a step of pre-separating gypsum waste from the rest of the construction waste material. In this pre-separating step, the gypsum waste is separated from other construction waste with a grapple excavator or by hand. The gypsum waste is then placed in containers separately from other construction waste for further treating.

An arrangement for making reusable gypsum material from construction waste material comprising gypsum waste according to the invention comprises a pre-processing device arranged to process gypsum waste such that the first pre-processing device is arranged to separate paper material and gypsum material from the gypsum waste and crush the gypsum material in the same process step to provide a separated gypsum material, and a processing device arranged to clean the separated gypsum material from impurity particles to provide reusable gypsum material.

The pre-processing device simultaneously separates paper material and gypsum material so that the crushable gypsum material is only gypsum. The simultaneous separation is preferably arranged such that when the paper material is detached from the gypsum material, the gypsum material crushes, and the paper is directed elsewhere in the pre-processing device so that the paper and the crushed gypsum material are separated. The advantage of the simultaneous separation and crushing in the pre-processing device is that the process is effective and can be implemented without complex process lines.

In other words, the pre-processing device is arranged to tear the paper material from the gypsum waste and crush the remaining gypsum of the gypsum waste in the same process step and preferably at the same time so that at the preprocessing device the paper material torn and separated when the gypsum remaining from the gypsum waste crushes and preferably moves away from the paper material, for example to the other side of a screening bucket.

According to the invention the processing device comprises a first processing device which is arranged to remove impurity particles from the separated gypsum material by screening the separated gypsum material with a mesh to provide reusable precleaned gypsum material.

The mesh is arranged to screen the separated gypsum material such that the impurity particles having larger particle size remain on the mesh while the gypsum material goes through the mesh to become reusable precleaned gypsum material. The mesh has a mesh size between 1-50 mm, more preferably 1 - 20 mm, preferably 2-15 mm and most preferably 3-10 mm. When the first processing device is the only processing device for cleaning the separated gypsum material then the reusable precleaned gypsum material that is obtained in the first cleaning step in the first processing device is the reusable gypsum material when no further cleaning is required.

According to the invention the processing device comprises a first processing device which is arranged to remove impurity particles from the separated gypsum material with a magnet to provide reusable precleaned gypsum material.

The first processing device can also be a combination of a screen with a mesh and a magnet such that the mesh removes the larger impurity particles while allowing the gypsum material having the particle size smaller than the mesh size to go through the mesh and the magnet removes all the metallic impurity particles either larger or smaller than the mesh size depending on the position of the magnet relative to the mesh.

According to the invention the processing device comprises a first processing device which is arranged to remove impurity particles from the separated gypsum material with a vibrating screen to provide reusable precleaned gypsum material.

According to the invention the processing device comprises a second processing device which is arranged to remove impurity particles from the separated gypsum material with a wind shifter such that the air is arranged to separate the separated gypsum material and the impurity particles which are heavier than the gypsum material to provide reusable cleaned gypsum material. Alternatively, the processing device comprises a second processing device which is arranged to remove impurity particles from the reusable precleaned gypsum material with a wind shifter such that the air is arranged to separate the reusable precleaned gypsum material and the impurity particles which are heavier than the gypsum material to provide the reusable gypsum material. The air that is arranged to separate the separated gypsum material and the impurity particles is an air flow that separates the separated gypsum material and the impurity particles. Also, the air that is arranged to separate the reusable precleaned gypsum material and the impurity particles is an air flow that separates the reusable precleaned gypsum material and the impurity particles.

This means that the second processing device can be arranged after the pre-processing device or after the first processing device. When the second processing device is arranged after the pre-processing device, the separated gypsum material is already clean enough that the second processing device is sufficient for the final cleaning of the separated gypsum material alone to obtain the reusable gypsum material. When the second processing device is arranged after the first processing device, the separated gypsum material goes through two cleaning steps, first in the first processing device in which the impurity particles are either removed according to the particle size and/or magnetic properties and secondly in the second processing device in which the impurity particles are removed based on the weight of the impurity particles.

According to the invention the pre-processing device is a screening bucket which is arranged to tear the paper material from the gypsum waste simultaneously as the gypsum waste is crushed to provide crushed separated gypsum material.

According to the invention the first processing device is a drum screen or vibrating screen. The drum screen has a mesh having the mesh size preferably between l-20mm, or between 2-15 mm or between 3-12 mm, for example 4mm.

In a preferable embodiment of the invention the screening bucket and the drum screen are connected to each other one on top of the other so that the crushed gypsum material is automatically transferred from the screening bucket to the drum screen for further processing while the paper material separated from the gypsum waste remains in the screening bucket or transferred therefrom to another location.

According to the invention the second processing device is a wind shifter which is arranged to blow the separated gypsum material or the reusable precleaned gypsum material such that the reusable gypsum and the impurity particles are separated.

The first and second processing devices can be connected together through a conveyor for moving the gypsum material from the first processing device to the second processing device.

According to the invention the arrangement for making reusable gypsum material from construction waste material comprising gypsum waste is arranged indoors such that the received construction waste to be processed and cleaned is sorted and stored in a building with concrete floors. The reusable gypsum material is stored in multi-lift containers with a capacity of 10-30 m ³ .

An advantage of the invention is that the method for producing reusable gypsum material can be implemented in connection with existing production lines and it does not require separate nor complex production lines. The arrangement can be operated with only one or two persons so that it requires a minimum number of person-working hours. Construction waste can be treated as soon as it is generated or arrived, or even on site, as the devices in the arrangement are easy to install and move on site if required. A further advantage of the invention is that cleaning of gypsum material can be performed as a dry material indoors. A further advantage of the invention is that the arrangement comprising devices can be built to clean gypsum waste automatically or almost automatically.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention is described in detail by means of specific embodiments with reference to the enclosed drawings, in which

Figure 1 shows a flow chart of the method and arrangement according to the invention;

Figure 2 shows a flow chart of one embodiment of the method and arrangement according to the invention;

Figure 3 shows a flow chart of another embodiment of the method and arrangement according to the invention; and

Figure 4 shows a flow chart of third embodiment of the method and arrangement according to the invention.

DETAILED DESCRIPTION OF THE INVENTION

Figure 1 shows a flow chart of the method and arrangement according to the invention in which gypsum waste 20 is fed to a pre-processing device 100 which is arranged to process gypsum waste 20 simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1 - 50 mm. The grain size can be preferably of 0.1 - 40 mm, or 0.1 - 30 mm, or 0.1 - 20 mm. The separated gypsum material 30 is obtained from the preprocessing device 100 and further fed to a processing device 200 which is arranged to clean the separated gypsum material 30 by removing impurity particles from the separated gypsum material 30. The reusable gypsum material 10 is the end product of the arrangement which is obtained from the processing device 200. The reusable gypsum material 10 obtained by the method and the arranged is cleaned and crushed gypsum material to be used as gypsum powder in new products.

Figure 2 shows a flow chart of one embodiment of the method and arrangement according to the invention in which gypsum waste 20 is fed to a preprocessing device 100 which is arranged to process gypsum waste 20 simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1 - 50 mm similarly as in the method and arrangement shown in figure 1. The grain size can be preferably of 0.1 - 40 mm, or 0.1 - 30 mm, or 0.1 - 20 mm. The separated gypsum material 30 obtained from the pre-processing device 100 is further fed to a first processing device 201 which is arranged to remove impurity particles from the separated gypsum material 30 by screening the separated gypsum material 30 with a mesh to provide reusable precleaned gypsum material 10.1. In other words, the reusable precleaned gypsum material 10.1 is obtained from the first processing device 201 by removing impurity particles with a screen for dividing the separated gypsum material 30 into reusable gypsum material 10 and impurity particles. The reusable precleaned gypsum material 10.1 is in some cases clean enough to be further used as reusable gypsum material. Therefore, the gypsum material obtained from the first processing device 201 can be either reusable precleaned gypsum material 10.1 if it is further cleaned in a second processing device 202 or reusable gypsum material 10 if it is clean enough after the first cleaning step in the first processing device to be reused as such. The arrow in figure 2 extending from the first processing device

201 can therefore be the reusable precleaned gypsum material 10.1 or the reusable gypsum material 10.

Figure 3 shows a flow chart of another embodiment of the method and arrangement according to the invention in which gypsum waste 20 is fed to a preprocessing device 100 which is arranged to process gypsum waste 20 simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1 - 50 mm similarly as in the method and arrangement shown in figures 1 and 2. The grain size can be preferably of 0.1 - 40 mm, or 0.1 - 30 mm, or 0.1 - 20 mm. The separated gypsum material 30 obtained from the pre-processing device 100 is further fed to a second processing device

202 which is arranged to remove impurity particles from the separated gypsum material 30 by dividing the separated gypsum material 30 according to weight such that the impurity particles which are heavier than gypsum material are separated from the separated gypsum material 30 by air. The second processing device 202 therefore is a wind shifter in which the separated gypsum material 30 is supplied and moving air, i.e., an air flow, blows the lighter gypsum material away from the heavier impurity particles and thereby the reusable cleaned gypsum material 10.2 is obtained. The separated gypsum material 30 may be clean enough to be further cleaned only in the second processing device 202 so that the feed to the second processing device 202 is the separated gypsum material 30 as such. Figure 4 shows another embodiment in which the feed to the second processing device is the reusable precleaned gypsum material 10.1. The gypsum obtained from the second processing device 202 is a reusable cleaned gypsum material 10.2 which is used as the reusable gypsum material 10 for new products. Therefore, the reusable cleaned gypsum material 10.2 is the reusable gypsum material 10 produced by the method and the arrangement.

Figure 4 shows a flow chart of third embodiment of the method and arrangement according to the invention in which gypsum waste 20 is fed to a preprocessing device 100 which is arranged to process gypsum waste 20 simultaneously removing paper material from the gypsum waste and crushing the gypsum waste to a grain size of 0.1 - 50 mm similarly as in the method and arrangement shown in figures 1, 2 and 3. The grain size can be preferably of 0.1 - 40 mm, or 0.1 - 30 mm, or 0.1 - 20 mm. The separated gypsum material 30 obtained from the pre-processing device 100 is further fed to a first processing device 201 which is arranged to remove impurity particles from the separated gypsum material 30 by screening the separated gypsum material 30 with a mesh to provide reusable precleaned gypsum material 10.1. In other words, the reusable precleaned gypsum material 10.1 is obtained from the first processing device 201 by removing impurity particles with a screen for dividing the separated gypsum material 30 into reusable gypsum material 10 and impurity particles. The reusable precleaned gypsum material 10.1 obtained from the first processing device 201 is further fed to a second processing device 202 which is arranged to remove impurity particles from the reusable precleaned gypsum material 10.1 by dividing the reusable precleaned gypsum material 10.1 according to weight such that the impurity particles which are heavier than gypsum material are separated from the reusable precleaned gypsum material 10.1 by air. The second processing device 202 therefore is a wind shifter in which the reusable precleaned gypsum material 10.1 is supplied and air flow blows the lighter gypsum material away from the heavier impurity particles and thereby the reusable cleaned gypsum material 10.2 is obtained as described in connection with figure 3 which is the reusable gypsum material 10.

The invention has been described above with reference to the examples shown in the figures. However, the invention is in no way restricted to the above examples but may vary within the scope of the claims.