Reuse of medium in a process in which materials with different specific gravities are separated into a floating and a sinking fraction by means of the medium

Abstract

The present invention relates to a method for the reuse of medium in a process in which materials with different specific gravity are separated by means of the medium into a floating and a sinking fraction, comprising: the separation of the floating and the sinking fraction in a density separator, the separation of the medium from the floating fraction and the sinking fraction by means of a sieve, whereby at least part of the separated medium is transported to a separator, whereby the said part of the separated medium is separated into density agent and water, whereby the density agent and the water are mixed together in a medium tank in a ratio according to a desired density of the medium, the ratio for obtaining the desired density being determined by density measurements in the medium tank,where the separated medium is added to the density separator from the medium tank and optionally from a suspension tank, whereby the quantity of medium to be added from the medium tank and / or the suspension tank is determined by density measurement in the density separator.

Description

2 use to create a more stable medium. In addition, a flotation drum is less suitable due to the turbulence in the medium, which reduces the separation efficiency. The present invention aims to find at least a solution for some of the above-mentioned problems or disadvantages. SUMMARY OF THE INVENTION In a first aspect, the present invention concerns a method according to conclusion 1.10 The combination of the density separator, the sieve, the separator and the medium tank are advantageous for the reuse of a medium in a process for separating materials with different specific gravity.In this method, the isolated medium is separated from the floating and sinking fractions by means of a sieve in combination with the settling of the density agent in the separator, the addition of the settled density agent and water to the medium tank in the ratio of water to settled density agent according to the desired density determined by density measurements in the medium tank, and the addition of the medium from the medium tanks and optionally from the suspension tank to the density separator according to the desired density of the medium in the density separator, determined by density measurements in the density separator. Additionally, this combination allows for the flexible application of the process for separating materials with different specific gravity by means of the medium, because the desired density of the density separator can be adjusted easily and accurately by adding more or less water or settled density agent to the medium tank or optionally by add a density agent to the suspension tank.An additional advantage is the precise / efficient adjustment of the density of the medium within a narrow range, such as for separating different plastics based on their densities. Preferred forms of the device are set out in claims 2 to 9. 35 BE2024 / 5897 3 In a second aspect, the present invention concerns a device according to claim 10. The device is the density separator combined with the sieve, the separator and the medium tanks and optionally the suspension tank. This combination of components is advantageous because it can offer the possibility of flexibly deploying the process for separating materials with different specific gravity by means of the medium, because the desired density of the density separator can be easily adjusted by adding more or less water or settled density agents to the medium tank or optionally by adding fresh density agents to the suspension tank.For this purpose, sensors are preferably present in the density separating medium tank which can generate electronic signals and serve to control valves for the discharge of components of the device. Additionally, various plastics can be separated based on their densities, since these are found within a narrow range of densities and the device can be efficiently adjusted to obtain the desired density of the medium in the density separator. The device is particularly advantageous for the reuse of medium. Preferred forms of the method are described in the following conclusions 11 to 20 and with 18. In one aspect, the present invention concerns a use in accordance with conclusion 19. This use results in separation using medium for car shredder residue or waste from electrical and electronic equipment. DESCRIPTION OF THE FIGURES Figure 1 shows a schematic overview of steps in a procedure according to an embodiment of the present invention.DETAILED DESCRIPTION Unless otherwise defined, all terms used in the description of the invention, including technical and scientific terms, have the meaning as they are generally understood by the expert in the technical field of the BE2024 / 5897 4 invention. For a better assessment of the description of the invention, the following terms are explicitly explained. “A”, “the” and “the” in this document refer to both the singular and the plural unless the context clearly implies otherwise. For example, “a segment” means one or more than a segment. The terms “comprising”, “comprising”, “consisting of”, “consisting of”, “provided with”, “contain”, “containing”, “include”, “containing” are synonyms and are inclusive or open terms that indicate the presence of what follows, and that do not exclude or prevent the presence of other components, characteristics, elements, members, steps, known from or described in the standard technique.The quotation of numerical intervals by the endpoints comprises all integers, fractions and / or real numbers between the endpoints, including these endpoints.15 In a first aspect, the invention concerns a method for the reuse of medium in a process whereby materials with different specific masses are separated into a floating and a sinking fraction by means of the medium.20 The method comprises the steps of: - introducing the materials to be separated into the medium in a density separator, comprising an aqueous suspension of a density agent, - removing the floating and sinking fractions of the materials,25 - separating the medium from the floating and sinking fractions, and - adding the separated medium to the medium in which the materials to be separated are introduced.30 In an implementation form, the method comprises separating the medium from the floating and sinking fractions.Separating the medium ensures that the medium can be reused after removing the floating and sinking fractions from the density separator. The medium is separated by means of a sieve. This sieve is advantageous for separating the medium from the floating and sinking fractions because it is simple to design, use, and maintain. Furthermore, the sieve offers a direct separation based on the size of the density agent and the floating and sinking fractions. Alternatively, the separation of the medium can be carried out by means of a cyclone or a decanter centrifuge. The cyclone has the advantage of achieving high efficiency and requiring minimal maintenance due to the absence of moving parts. The decanter centrifuge is very efficient for solid-liquid separation based on the size of the solid substance in the medium; furthermore, the decanter centrifuge can process large volumes and automatically discharge separated materials. In one configuration, at least part of the separated medium is transported to a separator.The aforementioned part of the separated medium is split into the density agent and water in the separator. The splitting of the aforementioned part of the separated medium is achieved by means of the settling of the density agent in the separator. By settling the density agent, a simple separation can take place based on density differences. Furthermore, settling requires no energy. Alternatively, the splitting can be carried out by means of decanter centrifugation, filtration, or cyclonic separation. Decanter centrifugation is very efficient for solid-liquid separation based on the size of the solid substance in the medium; furthermore, a decanter centrifuge can process large volumes and automatically discharge separated materials. Filtration is suitable for separating solids and liquids; it is simple to use, and it is not necessary to use chemical additives for the separation, making it an environmentally friendly choice.Cyclonic separation offers high efficiency, minimal maintenance due to the absence of moving parts, and a compact design that is beneficial for limited installation space. 30 In a specific configuration, the settled density agent is transported from the separator to a medium tank. In the medium tank, the settled density agent and water are mixed together in a ratio according to the desired density of the medium. The stated ratio for achieving the desired density of the medium is determined from density measurements in the medium tank. Preferably, there is a feedback loop between the density measurements in the medium tank and the control of the supply valves for the settled density agent BE2024 / 5897 6 and the water. The addition of the density agent and the water in the ratio according to the desired density of the medium tank offers the possibility to regulate and adjust the density of the medium in the medium tank.In one implementation form, the separated medium is added to the density separator from the medium tanks and optionally from a suspension tank, whereby the quantity of medium to be added from the medium tanks and / or the suspension tank is determined by density measurement in the density separator. Preferably, there is feedback from density measurements in the density separator to a control of a supply of medium from the medium tanks and / or the suspension tank. The addition of the medium from the medium tank according to the desired density in the density separator offers the possibility to regulate and adjust the density of the medium in the density separator.In a preferred load-bearing configuration, the separated medium is separated from the floating and sinking fractions by means of a sieve in combination with the settling of the density agent in the separator, the addition of the settled density agent and the water into the medium tank in the ratio of the water to the settled density agent according to a desired density determined by density measurements in the medium tank, and the addition of medium from the medium tanks and optionally from the suspension tank to the density separator according to the desired density of the medium in the density separator, determined by density measurements in the density separator. This combination of steps is advantageous according to the above-mentioned benefits.Additionally, the combination offers the possibility of flexibly deploying the process for separating materials with different specific gravities by means of the medium, because the desired density of the density separator can be easily and accurately adjusted by adding more or less water or settled density agents to the medium tank, or optionally by adding fresh density agents to the suspension tank. An additional advantage is the ability to adjust the density of the medium in the medium tank within a narrow range, such as for separating different plastics based on their densities. This narrow range is usually located between 0.80 kg / l and 2.15 kg / l. In one implementation form, the method includes the additional step of decanting the water from the separator. This occurs during the separation of the isolated medium in the separator. After decanting, the water is collected in a water tank. Decanting water from the separator ensures efficient separation of solid density agents.Collecting water in a water tank after decanting facilitates collection and storage for reuse. Decanting is energy-efficient, can be performed continuously, and requires little maintenance. 5 In a further form of implementation, the method includes the additional step of settling the density agent at the bottom of the separator. The settled density agent is collected at the bottom of the separator. The density agent can be easily collected at the bottom of the separator, meaning no additional storage facility is required. Moreover, the density agent remains partially in suspension, which simplifies transport between different installations for carrying out the method. This is possible with frequent removal of the density agent from the separator. Due to the frequent removal, the separator does not become oversaturated with density agents and the medium in the density separator is replenished in a timely manner. Preferably, the separator includes a mixer for keeping the density agent in suspension in the medium.In one design form, the density agent settles at the bottom of the separator and the settled density agent is stored in a suspension tank. Preferably, the suspension tank is topped up with fresh undissolved density agent.20 Storing the density agent in the suspension tank prevents oversaturation of the separator with density agent. Moreover, the suspension tank is easily topped up with fresh undissolved density agent when the suspension has a lower density than the medium in the medium tank. This ensures that the density of the suspension remains consistent and the efficiency of the separation process in the density separator can be maintained. In one implementation form, the method includes the additional step of separating the separated medium by decanting the water in the discharged medium over lamellae to adjacent lamellae. The separator is a 30-lamella separator. The density agent is retained by the lamellae and settles along the lamellae to the bottom of the lamella separator.The lamella separator has an increased separation surface in a compact design. Furthermore, the lamella separator increases the efficiency of sedimentation, causing the separation of solids and liquids to proceed faster and more effectively. This leads to a higher processing capacity without the need for a large installation. BE2024 / 5897 8 In an alternative design form, the separator is a decanter centrifuge. The separation of the separated medium is achieved by draining the water in the discharged medium along a rotating screw. The water flows out of the decanter centrifuge in the opposite direction to the transport direction of the rotating screw. The rotating screw carries the density signal along the transport direction of the screw. The decanter centrifuge is very efficient for solid-liquid separation based on the size of the solid substance in the medium. Furthermore, the decanter centrifuge can process large volumes and automatically discharge separated materials.10 In one implementation form, the method comprises the additional step of a portion of the separated medium flowing through a filter, prior to the separator. Coarse particles are separated on the filter and the filtered medium is pumped to the separator. 15 In a further implementation form, the filter is a belt filter. At least a portion of the separated medium is placed on a belt in the belt filter, through which the medium passes, and coarse particles comprising agglomerated density agents are separated. The coarse particles are carried along by the belt. The medium passing through the belt is transported to the separator. Preferably, the coarse particles are scraped off the belt and collected. Preferably, water used for contaminating the filter, more specifically the belt of the belt filter, is collected and added to an inlet stream of the filter.25 Filtering with a belt filter ensures efficient separation of coarse particles from the medium, including the agglomerated density, as well as fine pieces of the floating or sinking fraction from the medium. This increases the purity of the separated medium. An additional advantage is that the purity of the water also increases, thereby avoiding blockages of pumps and valves. Preferably, the water is returned to a filter inlet before contaminating the filter. This recirculation reduces water consumption and consequently contributes to a more sustainable and environmentally friendly method. Through this combination of benefits, the use of a belt filter improves the efficiency, quality, and sustainability of the separation process.35 BE2024 / 5897 9 In one implementation form, the method includes the additional step of directly transporting the separated medium through a first part of the sieve. to the medium tank. This is currently split into two parts.The separated medium originating from the first part of the sieve is collected or stored in the medium tank. Due to the direct flow of the medium from the first part of the sieve to the medium tank, sufficient medium is available to add the density separator. By pumping the medium out of the medium tank, a sufficiently high level of the medium is maintained in the density separator. Preferably, the separated medium from the first part of the sieve is first collected in a first tank beneath the first part of the sieve. The first part of the sieve is directly connected to the first tank. Preferably, the separated medium from the first part of the sieve is pumped over to the medium tank upon reaching a maximum level in the first tank. This prevents the first tank from overflowing. 15 In a further design, the separated medium is transported through a second part of the sieve to the separator. This allows at least part of the medium to be collected for reuse in the medium.Consequently, the separated medium can be readjusted to the desired density of the medium. Preferably, the separated medium is transported through the second part of the sieve prior to feeding into the separator to the filter. In a further form of implementation, the method includes the additional step of spraying off adhering medium from the floating or sinking fraction25 after the floating or sinking fraction has passed along the first part of the sieve. The sprayed-off medium is transported through the second part of the sieve to the separator. Preferably, the separated medium is transported through the second part of the sieve to the filter prior to feeding into the separator. This allows adhering density to be rinsed off the floating or sinking fraction and collected for reuse in the medium with the desired density. Preferably, the separated medium from the second part of the sieve is first collected in a second tank beneath the second part of the sieve. The second part of the sieve is directly connected to the second tank.Preferably, the separated medium is pumped from the second section of the sieve to the separator upon reaching a BE2024 / 5897 10 maximum level of the second tank. This prevents the second tank from overflowing. In one implementation form, the method involves pumping the medium from the medium tank to the filter. This allows the medium to be transported to the filter if the level of the medium in the medium tank is too high. Furthermore, pumping the medium from the medium tank to the filter can be used to restore the desired density in the medium tank. This leaves free volume in the medium tank that can be filled with density media from the separator or from the suspension tank. In one implementation form, the method involves the additional step of adding water to the medium tank to lower the desired density of the medium. Small fluctuations in the amount of water added to the medium during the separation of the materials into a floating and a sinking fraction are averaged and have no substantial influence on the average density of the medium in the medium tank.However, it is possible that less water is added to the medium over a longer period. This can be achieved, for example, by reducing the throughput of the materials to be separated, whereby less water is introduced into the density separator together with the materials to be separated, and the density of the medium decreases less rapidly. Another possibility is that a different separation of materials is desired. For example, the floating fraction must consist of only lighter materials. For this, it is necessary to reduce the desired density of the medium in the density separator. A portion of the materials that were previously discharged with the floating fraction will now sink to the bottom of the density separator. The density of the medium can be reduced by adding water to the medium tank until the desired density is reached. Because the medium leaving the density separator is compensated by the medium from the medium tank, the medium in the density separator will also reach the desired average density.This step of the procedure is suitable for gradually reducing the average density of the medium during the separation of materials. BE2024 / 5897 11 A rapid reduction of the desired density is possible in a design where water is added directly to the density separator. In a design, the procedure includes the additional step of adding density agents to the medium tank to increase the average density of the medium. It is also possible that more water is added to the medium over a longer period. This can be done, for example, by increasing the throughput of the materials to be separated, whereby more water is introduced into the density separator together with the materials to be separated, causing the density of the medium to decrease more rapidly. If the density of the medium in the medium tank is not adjusted, the density of the medium in the density separator will gradually decrease and a correction will be required after a period of time.15 It is also possible that for another desired separation of materials, the sinking fraction only needs to comprise the heaviest materials. For this, it is necessary to increase the desired density of the medium in the density separator. A portion of the materials that previously sank to the bottom of the density separator will now be discharged with the floating fraction.20 The average density of the medium can be increased by adding density agents to the medium tank until the desired average density is reached. Again, because the medium leaving the density separator is compensated by the medium from the medium tank, the medium in the density separator25 will also reach the desired higher average density. This step of the procedure is suitable for gradually increasing the average density of the medium during the separation of materials. 30 Preferably, this step of the procedure is applied to obtain a rapid increase in the average density of the medium in the density separator in the event that another separation of materials is desired.In a further implementation form, the densifying agent is added from the bottom of the separator. Preferably, the addition of a quantity of densifying agent to the medium tank is controlled by density measurements in the BE2024 / 5897 12 separator. Preferably, the opening and closing of the supply valve from the separator to the medium tank is controlled by the density measurements in the separator and optionally by the density measurements in the medium tank. This allows the desired density in the medium tank to be obtained quickly. In a further implementation form, the method involves mixing the medium tank by one or more mixing elements. This keeps the composition of the medium in the medium tank consistent. Preferably, one mixing element rotates in the medium tank. 10 In a specific implementation form, water is added to the water tank externally to the method. The addition of external water helps maintain the water level in the water tank, and additionally in the medium tank and suspension tank. This contributes to the stability and continuity of the method.15 In one execution form, water is added to the separator. Preferably, the water is added to the separator at the bottom of the separator to keep the density agent at the bottom of the separator sufficiently suspended. Preferably, said water comes from the water tank. Adding water to the separator helps to keep the density agent in suspension, which increases the efficiency of the separation process. In one execution form, water is added to the sieve for cleaning the sieve. Preferably, said water comes from the water tank. 25 In one execution form, water is sprayed onto the filter for cleaning the filter. Preferably, said water comes from the water tank. Adding water facilitates the cleaning of filters and sieves, thereby preventing blockages and reducing maintenance on the sieves and filters. In one implementation form, the method comprises the step of homogenizing the medium density separator using a conveyor screw.The conveyor screw is used to remove the sinking fraction from the 35 density separator. Preferably, no additional mixing elements are present in the BE2024 / 5897 13 density separator so that the sinking and buoyancy of the material to be separated is not disturbed. In one form, the medium is a suspension of water with an additive. The additive is preferably calcium carbonate or kaolin, with greater preference for calcium carbonate. Alternatively, magnesium carbonate, barium sulfate, zinc sulfide, or strontium sulfate may be used. The advantage of these additives, and more specifically salts, is that they are poorly or not at all soluble in water, making a suspension of the density agent and water possible. As a result, the density agent can be separated from the medium by means of simple and energy-efficient methods, such as sedimentation or sieving. This is in contrast to soluble salts, which can only be recovered by reverse eososis or evaporation.In a preferred load-bearing form, the additive has a density less than 5.0 kg / l; preferably, the density of the additive is less than 4.0 kg / l, and in a more favorable form, less than 3.0 kg / l. Due to their low density, it is easier to adjust small variations in the desired density of the medium in the density separator or in the medium tank. Other options for the additives would be ferrite or ferrosilicon, due to the advantage that both density agents can be isolated from the medium because of their magnetic properties. However, these are less suitable for adjusting small fluctuations in the medium. In a specific form, the density agent is present in the medium in a ratio of 2 wt% to 30 wt% to the total weight of the medium, preferably 3 wt% to 25 wt%, and more preferably 4 wt% to 25 wt%. The 25 weight percentage of the density agent added to the water is low, so that the flow behavior of the suspension does not differ significantly from that of water. As a result, the transport and pumping of the medium are simple and energy-efficient.Moreover, sufficient wetting of the materials to be separated is possible with the medium in the density separator.30 In a second aspect, the invention concerns a device for the reuse of medium in a process in which materials with different specific gravity are separated into a floating and a sinking fraction by means of the medium.35 BE2024 / 5897 14 The device comprises a density separator for separating the materials to be separated in a medium, a separation plant for separating the medium from the floating and sinking fraction, a separator for separating the medium into density agent and water, and a medium tank for mixing the medium.5 In a design form, the density separator comprises a first feed, a second feed, a first discharge and a second discharge. The first feed serves for introducing the materials to be separated. The second feed serves for introducing of a medium. The first discharge serves to discharge the floating fraction.10 The second discharge serves to discharge the sinking fraction.In one design form, the separation plant is a sieve. This sieve comprises an inlet, a first outlet, and a second outlet. The inlet of the sieve serves to introduce the floating or sinking fraction from the density separator. The first outlet serves to discharge the medium. The second outlet serves to discharge a sieved floating or a sieved sinking fraction. Preferably, the device comprises two sieves. A first sieve serves to separate the medium from the floating fraction. A second sieve serves to separate the medium from the sinking fraction. This sieve, or either of the two sieves, is advantageous for separating the medium from the floating or sinking fraction because it is simple to design, use, and maintain and operates without electricity. Moreover, the sieve offers direct separation based on size of the density agent, and the floating and sinking fraction. 25 Alternatively, the separation plant is a cyclone or a decanter centrifuge.The cyclone has the advantage of achieving high efficiency and requiring minimal maintenance due to the absence of moving parts. The decanter centrifuge is highly efficient for solid-liquid separation based on the size of solid substances in the medium; furthermore, the decanter centrifuge can process large volumes and discharge automatically separated materials. In one design, the separator comprises an inlet, a first outlet, and a second outlet. The inlet serves to introduce at least part of the medium from the separation plant, preferably the sieve. The first outlet serves to decant water. Decanting the water from the said part of the separated medium in the separator allows for simple separation based on density differences. Furthermore, decanting requires only minimal energy. The second drain serves to discharge the densifying agent. Preferably, the second drain is positioned at the bottom of the separator. Through the second drain, the densifying agent can be removed separately from the separator.This allows the density agent to form a separate stream, and that stream can be added to water in a desired ratio. Preferably, said water originates from the separator. This allows optimal reuse of density agents and water from the medium originating from the density separator10 to be pursued. In one configuration, the medium tank comprises a first stone inlet, a second inlet, and an outlet. The first stone inlet serves for the introduction of water, preferably from the water tank. The second inlet serves for the introduction of density agents from the separators and / or the suspension tank. Preferably, the medium tank comprises a third inlet for the introduction of density agents from the suspension tank. The outlet serves to discharge the medium to the density separator. The medium tank is a buffer to absorb fluctuations in the level of the density separator. The medium tank also serves to absorb fluctuations in measured density in the density separator. In one configuration, the medium tank comprises a sensor for measuring the density.The sensor mentioned serves to measure the density in the medium tank. Preferably, a density measurement feedback system25 is used by the density sensor to control a supply valve from the medium tank to the density separator. The supply valve is located at the outlet of the medium tank. This is advantageous for controlling and regulating the addition of the medium from the medium tank in a quantity according to the desired density of the density separator.30 In a preferred load-bearing configuration of the device, the density separator is combined with the sieve, the separator, and the medium tank. This combination of components is advantageous according to the above-mentioned benefits. Additionally, the combination offers the possibility of flexibly deploying the process for separating35 materials with different specific gravity by means of the medium, because the desired density of the density separator can be easily adjusted BE2024 / 5897 16 by adding more or less water or a density agent to the medium tank.For this purpose, sensors are preferably present in the density-separating medium tank which can generate electronic signals and serve to control valves on the discharge of components of the device. The valves can be inlet valves. Additionally, various plastics can be separated based on their densities, as they are found within a wide range of densities. The device can be efficiently adjusted to obtain the desired density of the medium in the density separator. In one configuration, the device includes a water tank for storing water. The water tank includes an inlet which serves to introduce water from the separator. The water tank includes an outlet for transporting water to the medium tank. In a further configuration, the water tank comprises a second outlet for transporting water from the water tank to other components in the installation, such as the density separator, the screen, the filter, and the separator. Alternatively, the second outlet can serve to supply water to other installations outside this facility.20 In an implementation form, the facility comprises a second inlet for adding water external to the facility. The water tank is advantageous as a buffer for regulating the desired densities in density separators and / or the medium tank. Furthermore, the water tank is advantageous for utilizing water for rinsing and cleaning components of the device, such as filters or sieves. Moreover, the water tank can be used to maintain the level of the density separator so that sufficient medium is present in the density separator for the optimal separation of the materials to be separated. In one design form, the separator is a lamellar separator. The lamellar separator comprises lamellae. The lamellae form an angle of at least 45° and at most 75° with respect to a horizontal plane. The lamellae serve for the settling of the density agent against the lamellae and the decanting of water and the medium over the lamellae. Preferably, the lamellae form an angle of at least 50° with respect to of a horizontal plane, preferably at an angle of at least 55°, preferably at BE2024 / 5897 17 preferably at an angle of at least 57°.Preferably, the lamellae form an angle of at most 70° with respect to a horizontal plane, more preferably an angle of at most 65°, more preferably an angle of at least 63°. The lamella separator has an increased separation surface in a compact design. Furthermore, the lamella separator increases the efficiency of sedimentation, whereby the separation of solids and liquids proceeds faster and more effectively. This leads to a higher processing capacity without the need for a large installation. In one design form, the device comprises a filter for the removal of coarse particles. The filter comprises an inlet, a first outlet, and a second outlet. The inlet serves to introduce the medium from the sieves and / or the medium tank. The first outlet serves to discharge the medium, preferably to the separator. The second outlet serves to discharge coarse particles. Coarse particles comprise agglomerated density agents and / or small material particles originating from the floating or sinking fraction.15 In one design form, the filter has a pore size of at least 600µm, preferably at least 400µm, more preferably at least 200µm, more preferably at least 100µm. 20 In one design form, the filter is a belt filter, a screw filter, a chamber filter press, a belt filter press, a rotary filter, or a vibrating filter. Preferably, the filter is a belt filter so that the filter has a simple and low-maintenance design and the coarse particles can be easily scraped off. 25 Due to the presence of the filter, the purity of the medium can increase. Furthermore, water used to contaminate the filter can be returned to a filter inlet, allowing for ecological operation. In one design form, the sieve is a vibrating sieve. The vibrating sieve has a pore size of at most 1 mm, preferably at most 750 µm, preferably 500 µm, and preferably 250 µm. This retains the floating and sinking fractions, but allows the density agent to move through the sieve. Consequently, recovery of the medium is possible. In one design form, the sieve comprises a first part and a second part.Between the first and second parts, a spray head is placed for rinsing off the medium from the sinking or floating fraction. This contains the first discharge in the second part of the sieve. Preferably, both parts of the sieve are vibrating sieves. This allows adhering density agents to be rinsed off the floating or sinking fraction by the spray head and collected for reuse in the medium with the desired density. In a further design, the sieve comprises a second tank. The second tank serves to collect the medium separated in the second part of the sieve. The second part of the sieve is preferably coupled directly to the second tank. The second tank preferably comprises a pump for transferring separated medium from the second part of the sieve to the separator upon reaching a maximum level of the second tank. This prevents the second tank from overflowing. In a design, the sieve comprises a third discharge in the first part. The third discharge serves to discharge the medium to the medium tank. Preferably, the third discharge is coupled to a first tank.The first tank serves to collect the medium separately in the first part of the sieve. The first part of the sieve is preferably directly connected to the first tank. The first tank preferably contains a pump for pumping isolated medium 20 from the first part of the sieve to the medium tank when a maximum level of the first tank is reached. This prevents the first tank from overflowing. Preferably, the drain comprises a split valve for the controlled discharge of the medium to the medium tank or the separator. Preferably, the split valve is electronically controllable.25 In one design form, the medium tank comprises one or more sensors for determining the density of the medium in the medium tank. Preferably, the number of sensors for determining the density in the medium tank is two. Preferably, the one or more sensors are positioned at a fixed depth in the medium tank30. Preferably, the medium tank comprises a level sensor for measuring the level of the medium in the medium tank.In one design form, a bottom section of the separator contains one or more sensors for determining the density of sediment in the separator. The sediment is settled density agent separated from water originating from the medium. As a result, the density agent is present in a more concentrated form than in the BE2024 / 5897 19 medium tank or density separator. Preferably, the number of sensors in the medium tank is at most six, preferably four sensors, or preferably two sensors. Preferably, one or more sensors are positioned at a fixed depth in the medium tank. Preferably, several sensors are positioned at different depths of the separator. Preferably, two of the several sensors are positioned near the bottom of the separator. “Near the bottom” means that those two sensors are positioned in a zone of the separator where the density agent can accumulate. Preferably, these two sensors are positioned where no lamellae are present in the lamella separator and near the second outlet of the lamella separator.In one design form, the density separator comprises one or more sensors for determining the density of the medium in the medium tank. Preferably, the number of sensors in the density separator is at most four, preferably three sensors, or preferably two sensors. Preferably, the one or more sensors are positioned at a fixed depth in the density separator. Multiple sensors positioned preferably at different depths of the density separator has the advantage that a variation in concentration over the depth of the density separator can be monitored. The degree of settling of density agents in the density separator is monitored thereby. If the medium is more concentrated than the desired density of the medium in the density separator, it can then be added to the top of the density separator. This allows the desired density of the medium in the density separator to be maintained for correct separation into floating and sinking fractions.Preferably, one or more sensors are positioned in one or more depths of the density separator such that density measurements can be taken in a non-turbulent zone. This allows for accurate measurement. The non-turbulent zone is a zone of the density separator located sufficiently far from the first stone, the second inlet, the first and second outlet, so that there are no turbulent flows in the medium caused by the introduction and discharge of materials. In a design form, the first stone / or the second tank comprises one or more sensors for determining the density of the medium in the first stone / or the second tank. Preferably, the number of sensors in the first stone / or the second tank for determining the density is two. Preferably, one or more sensors are positioned at a fixed depth in the first stone / or the second tank. Because the sensors can measure density, it can be decided whether the BE2024 / 5897 20 medium in the first stone / or the second tank can flow to the medium tank or to the separator for further reuse or separation of water and density agents.Preferably, the first stone / or the second tank includes a level sensor for measuring the level of the medium in the first stone / or second tank. 5 In a design, at least part of the one or more sensors are pressure sensors for determining the density of the medium. Preferably, all of the one or more sensors are pressure sensors. The pressure sensors can accurately, simply, and also for a non-transparent medium determine the density of the medium. Alternatively, optical sensors, sensors based on measuring sound waves, or other sensors can also be used. Sensors based on sound waves are advantageous due to their high accuracy and wide applicability in medium compositions. Optical sensors can perform rapid measurements, but these sensors are limited to a transparent medium. 15 In one design form, one or more sensors are pressure sensors and the pressure sensors have a measuring range between 0 kPa and 100 kPa, preferably between 0 kPa and 85 kPa, or preferably between 0 kPa and 70 kPa.This allows pressures to be measured accurately, enabling the efficient adjustment of the density of the medium in the density separator, in the medium tank, in the first or in the second tank. Alternatively, the density of the suspended solids in the separator can be determined. In one design form, the density separator is a flotation tank. The flotation tank comprises a screw conveyor and carriers. The screw conveyor serves to remove the sinking fraction from the flotation tank. The carriers serve to remove the floating fraction from the flotation tank. This allows the floating and sinking fractions to be transported to one end of the flotation tank for the efficient removal of both fractions from the flotation tank. Alternatively, the density separator is a rotatable drum, preferably a rotatable flotation drum. In one design form, the device comprises a suspension tank for storing the densifying agent in a concentrated suspension.The concentrated suspension is a suspension with a density such that the difference between the density of the concentrated suspension and the density of water at standard atmospheric pressures and at a temperature of 4°C is at least twice greater than the difference between the density of the medium in the medium tank and the density of water at standard atmospheric pressures and at a temperature of 4°C. Preferably, the suspension tank comprises a first stone feed, a second inlet, and an outlet. The first stone feed serves to introduce the settled density agent originating from the bottom of the separator. The second inlet serves to replenish the suspension tank with fresh, undissolved density agents. The outlet serves to discharge the concentrated suspension from the suspension tank, preferably into the medium tank. The ability to store the density agent in the The suspension tank prevents oversaturation of the separator with density-causing agents.Moreover, the suspension tank can easily be topped up with fresh undissolved density agents when the suspension has a lower density than the medium in the medium tank. Preferably, the suspension tank can be topped up with fresh undissolved density agents if the difference between the density in the suspension tank and the density of water at standard atmospheric pressures and at a temperature of 4°C is less than twice the difference between the density of the medium tank and the density of water at standard atmospheric pressures and at a temperature of 4°C. This ensures that the density of the suspension remains consistent and the efficiency of the separation process in the density separator can be maintained. In one design, the medium tank comprises one or more mixing elements. This ensures that the composition and density of the medium in the medium tank25 are kept consistent. Preferably, one mixing element rotates in the medium tank. In one design form, the suspension tank comprises one or more mixing elements.This ensures that the composition and density of the medium in the suspension tank remain consistent. Preferably, one mixing element rotates in the suspension tank.30 In one design form, the ratio of the volume of the medium tanks to the volume of the first or second tank is at least three, preferably at least four, but preferably at least five. This is advantageous so that adjustments and replenishment of the medium to the medium tank or a transfer to the separator35 can be carried out from the floating or sinking fraction from the density separator. BE2024 / 5897 22 In one design form, the ratio of the volume of the medium tanks to the volume of the density separator is at least one-fourth, preferably at least one-third, but preferably at least half. This is advantageous so that a sufficiently large buffer can be present for adjusting and / or replenishing the medium in the density separator.In one third aspect, the invention concerns the use of a method according to the first aspect and / or a device according to the second aspect for separating materials with different specific masses into a floating and a sinking fraction. This use results in separation using a medium for automatic shredder residue or waste from electrical and electronic devices. 15 It is advantageous that the method and the setup allow for efficient and accurate adjustment of the density of the medium within a narrow range, such as for separating different plastics based on their densities. This narrow range is usually situated between 0.80 kg / l and 2.15 kg / l, preferably between 0.85 kg / l and 1.75 kg / l. 20 A professional trained in the technical field will appreciate that a setup according to the second aspect is preferably configured for carrying out a method according to the first aspect and that a method according to the first aspect is preferably carried out with a setup according to the second aspect.Each feature described in this document, both above and below, may consequently relate to any of the three aspects of the present invention. The present invention will now be described in more detail, with reference to non-restrictive figures.30 FIGURE DESCRIPTION Figure 1: shows a schematic overview of steps in a method according to an execution form of the present invention.35 BE2024 / 5897 23.