CZ20002603A3 - Method for processing mixed waste, processing plant and buffer silos therefor - Google Patents

Abstract

The process of processing mixed waste in operation continuously a device that contains multiple consecutive devices following processing stations connected to each other at least one conveyor path in which it is mixed waste material is processed in at least one and / or transported at least once the transport route, the flow of mixed waste being at least one handover between station and transport between the two transport routes accelerates so that the following section of the processing line material spread over a longer route.

Description

Technical field

The invention relates to a process for the treatment of mixed wastes, in particular such mixed wastes, which consist of plastics, paper-plastic sandwiches, glass, metal, paper, cardboard and other impurities. The invention further relates to a plant for their treatment by said process including buffer tanks which are incorporated into the waste treatment plant.

Background

With the introduction of the dual system, the systemic recovery of the collected plastics has proved to be the most advantageous with regard to the packaging used in Germany.

In doing so, an entirely new fraction, namely a mixed plastic, appeared on the market. Due to their heterogeneity and changing composition, it was necessary to find new ways of their re-utilization for mixed plastics. For the utilization of mixed plastics, mainly raw material recovery is considered. The prerequisite for this is the treatment of the material to an agglomerate that meets the specified specifications. Because plastics are collected with a variety of contaminants within a dual system, processes are sought that reduce the cost of sorting them to an acceptable level while ensuring a specified degree of purity of the plastic material.

Metallic materials can be separated by magnetic and vortex separators. Heavy plastics and other heavy foreign particles are generally separated from the material to be processed by pneumatic sorting. Further, various processes for removing paper are known, in particular from sandwich paper-plastic materials.

With improved screening of polluting materials, dry processes can now be used to treat mixed plastics, whereby a high quality plastic agglomerate can be obtained at a comparatively lower energy consumption. The method disclosed in WO 96/20819 has become a widespread method in which the material to be processed is first crushed into smaller particles and free of magnetic materials. The crushed material is then compacted or agglomerated thermally by applying pressure in the agglomerator, whereby light substances such as water vapor, ash and paper are sucked off by means of a suction device. Then the agglomerated material is dried and finally sieved.

For reasons of economy, it is desirable to ensure continuous operation of the plant. This is not possible with the process known from WO 96/20819. Failure of a part of the equipment usually causes the whole equipment to stop and leads to outages due to repairs and maintenance of the equipment.

SUMMARY OF THE INVENTION

SUMMARY OF THE INVENTION It is an object of the present invention to provide a process for the treatment of mixed wastes consisting of plastics, paper-plastic sandwiches, glass, metal, paper, cardboard and other impurities so that the operation of the waste treatment plant is continuous.

This object is solved by the method set forth in claim 1. Useful devices are the subject of subclaims. A waste treatment plant according to the invention is defined in claim 9.

Process for treating mixed waste according to the invention in a continuously operating dry mechanical waste treatment plant comprising a plurality of successive processing stations connected to each other by at least one conveyor path having at least the following sequential steps: metal separation, pneumatic screening and paper removal, where appropriate, further steps may be inserted or immediately followed, characterized in that the raw material flow, when transferred to the last conveyor route in front of the processing station, achieves «·

acceleration, so that the average actual velocity of the raw material flow particles on the last conveyor path and thus immediately before entering the metal separation processing station is lower than before entering the pneumatic sorting processing station (here, perhaps, the text Nachichtichtung should be written in the text Windsichtung - see amended sheet) and this is again lower than the average speed before entering the paper removal processing station.

Here, the feedstock flow is a material flow of a qualitatively higher degree, that is to say the material to be further processed in the further course of the process, and the actual particle velocity is actually the traveled particle path over time.

Preferably, the mixed waste flow between two adjacent stations is conveyed at a substantially constant rate on the current conveyor path.

It may further be contemplated that a stock of possibly treated material will be deposited for at least one station.

DETAILED DESCRIPTION OF THE INVENTION

The process according to the invention is characterized by the following steps:

(a) crushing of mixed waste (b) intermediate deposition of crushed mixed waste (c) uniform transport of interposed mixed waste (d) separation of magnetic metallic particles (e) separation of non-magnetic particles from materials whose specific gravity exceeds an adjustable minimum specific weight , for example, paper-plastic sandwich materials (g) intermediate depositing the obtained plastic fraction and (h) agglomerating the plastic fraction.

· · · * * * * * * * * * * * * * * * * * * • * ·· ····· ·· · ·

By agglomeration is meant densification into a bulk material using thermal and / or discharging energy acting on the material to be agglomerated.

Optionally, further steps may be followed, for example, after intermediate deposition of the plastic fraction obtained, further separation of non-magnetic particles may follow. Furthermore, it may be advantageous to make the agglomerated plastic finer. If necessary, it is then expedient to re-separate those magnetic particles which can be magnetically separated after this finer particle size adjustment process.

According to another embodiment, the process according to the invention is conducted in such a way that the material to be processed on the designated conveying routes is conveyed pneumatically only.

The invention is based on the realization that a smooth and trouble-free operation is a prerequisite for a continuous process, which is ensured by accelerating the flow of the waste material to be treated, thereby practically achieving a kind of "expansion" of the material. This facilitates the separation of contaminants in the various pollutant separators.

The invention furthermore relies on the fact that the continuous process can be easily carried out by taking care to ensure intermediate deposition of the pretreated material at critical points in the processing process. As already explained, such waste crushers or mills are such critical components. Therefore, in one waste treatment plant, as a rule, several mills are provided, all of which operate in a single buffer tank. Failure of one of the mills then does not lead to a halt of the entire plant, since it is still possible to convey material from the buffer tanks to the next component of the plant.

It is also possible to take advantage of the known advantage of the cartridges that they homogenise the crushed material and that it can be conveyed to the following components of the device in a more uniform composition. The mills or waste shredders pulsate strongly during operation, making it evenly difficult to feed • · · 444

· 4 4 4 4

4 4 44 44 44 to the following separators. The buffer reservoir thus acts as a mechanical suppression of coupling between the individual components of the device.

Depending on the buffer reservoir, at least one magnetic separator may be provided, as well as at least one device for separating non-magnetic particles from substances of a specific weight that exceeds the adjustable lowest specific weight.

It has proved to be advantageous to use so-called gravity separators, which are the subject of the co-pending German patent 198 ...... (authentic document: DK 2860). Heavy metal and non-metallic particles are filtered out with these tube sorters, so that a swirl separator is generally not required. The device further comprises at least one paper removal device, e.g. which adjoins a buffer container in which the plastic fraction is collected from all paper separation devices.

This allows the use of a continuous disk compactor sold by Netsch Condux, Hanau under the designation CV 50.

The homogenizing and equalizing action of the buffer reservoir in which the plastic fraction is collected can be used to connect another device for separating heavy non-magnetic particles.

A buffer tank for a waste treatment plant which operates according to the process of the invention and which is connected to a mill or to a mill. mills, consisting of a container with at least one opening at the top of the container to be filled with the material to be stored and at least one opening for emptying the material, characterized in that it has several discharge screws in the bottom region, the screws being arranged to operate they cover the entire surface of the bottom and that it is provided with at least one forward worm which homogenises the discharge screw material.

This prevents large quantities of material from falling into the scraper conveyor blades at the same time.

The discharge screws can each work with a different sense of rotation, for example they can be right-handed or left-handed.

Advantageously, the discharge screws can be arranged parallel to each other and the forward screw is rotated 90 ° relative to the discharge screws. The forward auger may be right-handed or left-handed.

The buffer tank for the waste treatment device in which the plastic fraction is collected consists of a container with at least one opening at the top of the container for filling the material to be stored and at least one opening for material discharge, characterized in that it has at least one loosening screw, which is subjected to a vacuum, and that the at least one screw is supplied with air from the vessel by means of a suction device. Furthermore, special discharge screws are provided in the buffer reservoir, which convey the stored material to at least one leaking auger.

It has proven expedient to widen the buffer reservoir conically or trapezoid towards the bottom, depending on the shape of the plan, thus avoiding the formation of a bridge effect in the reservoir.

In the following, the invention will be explained in more detail with reference to the accompanying drawings. The illustrations show:

Giant. 1 with partial illustrations A, B, C, D and E schematically illustrates the process control of the waste treatment process using the invention

FIG. 2 is a longitudinal cross-sectional view of the buffer tank following one or more waste disposers

Fig. 3 is a longitudinal cross-sectional view of the buffer stack following the paper separator

Fig. 4 is a longitudinal section through the tube sorting station of station 6.)

Fig. 5 is a longitudinal sectional view of the tube sorter of the station 9.) a

Fig. 6 is a longitudinal sectional view of the agglomerator of station 10.)

Figures IA to E show schematically the process of processing waste into a plastic agglomerate according to the invention with stations 1 to 18. The arrows marked "1" indicate the direction of the flow

drive air, the arrows marked "2" indicate the flow of paper mass. The arrow with the number "3" indicates the flow of magnetic metals, the arrow with the number "4" indicates the flow of non-magnetic pollutants containing mainly glass, aluminum-coated plastics, damp and wet paper lumps, stones, wood, packaging with a plastic content of less than 50%; non-magnetic metals. The arrows with the number "5" ultimately indicate the flow direction leading to the desired plastic mixture, which is further processed into an agglomerate with a lower proportion of contaminants or other materials that have been filtered out at other stations.

The contaminated plastic mixture is, as shown in Fig. 1A, conveyed and unloaded (station 1) and marked (station 2) so that contaminants that cause agglomerate contamination or damage to equipment components can be clearly identified. The conveyed material is first crushed to a particle size (station 3) in a crusher or mill.

The plastic bales that have been brought into the mill press the retainer against the rotor at a specified pressure. The rotor crushes the fraction until the inserted material passes through a sieve located at a bottom having a certain hole diameter, for example 45mm. By inserting different sieves, the grain diameter of the ground material can be adapted to the requirements of the machine.

The ground material is then conveyed to a buffer container (station 4) by means of a chain scraper conveyor or the like, as shown in FIG. 1B. Experience has shown that a chain scraper conveyor is the most suitable in these demanding processing plant conditions. Alternatively, belt conveyors may be used. Both of these types of conveyors can be deployed on mechanically operated conveying paths of the device as required.

The buffer tank of the station 4 serves as the buffer tank of the station 8 as a storage station.

If a plurality of waste mills are arranged in parallel in the plant, they all operate through a conveyor path assembly for one buffer reservoir. It is also possible to connect the waste mills in series

9 9 4 4 4 449 94 * 4 4 4 * **** **** 9 9 4 4 * 4 * 9 * in a row, then one conveyor is sufficient. The filling level of the buffer tank is monitored manually. When the maximum filling level of the buffer tank is exceeded, the operator disconnects one or more devices from it. When the minimum state is reached, the device switches on again. Monitoring of the filling level can also be carried out automatically, for example by means of an optical sensor or by means of an aileron sensor, and when the first filling level is exceeded, one or more devices are automatically switched off. . The individual components of the buffer tank are shown in Fig. 2 and are described below.

The active chain scraper conveyor is uniformly supplied from the buffer reservoir and moves at a constant speed of, for example, 0.25 m / s. The conveyor has two openings, one of which has a variable profile formed by a pneumatic damper S.

From this conveyor, the material is divided into two vibrating troughs Via V2, which transport the material a little faster than the conveyor at a speed of 0.33 m / s. In the direction of movement, the first vibration trough VI opens as needed when, for example, two subsequent lines are to be supplied.

The damper S has three positions which are set according to whether only one line or both should be supplied. Above the vibrating trough V2, which is second in the direction of movement, the chain vanes have only one opening.

The vibrating troughs VI, V2 convey all material through the magnetic drums (station 5), in which case two magnetic drums are fitted according to the number of troughs. Metal particles fall on vibrating troughs due to their specific weight and shaking of fractions to the bottom. This allows almost complete separation of heavy metal particles from light plastics. It would be optimal if the metal particles are trapped in one layer on the magnetic drums. This is very difficult to achieve in practice.

The magnet in the magnetic drum has an efficiency angle of 180 °. The mixed plastics material falls at an angle of 90 ° to 180 ° into the hopper. Magnetic · »4« · 4

44 44

4 4444 4444

4,444,444

the metal particles remain attached to the drum, by means of the rotation of the drum they move outside the magnetic force field and fall into the second hopper, which is located behind it. The metal is transported by a chain scraper conveyor to a container where it is collected. It has been found that the use of drums is preferable to the commonly used magnets placed above the belts, since in the latter the foils also adhere to the metal particles. This undesirably increases the amount of plastics which are thus separated. Furthermore, small metal particles are not separated.

The conveying of the fraction is further taken up by screw conveyors which convey the material at a speed of, for example, 0.51 m / s. They loosen material for downstream tube sorters (station 6), in which heavy non-magnetic particles are separated by vacuum, and where the flow rate of the material is increased to 5 to 25 m / s. The individual parts of the tube sorter assembly are shown in Figures 4 and 5.

Heavier and stuck polluting materials fall on chain vanes (not shown) that collect the separated material and transport it to the container. There remains a recoverable composite plastic which is pneumatically conveyed to the paper separation point by a pressure fan. The air flow has a velocity of eg 25 m / s.

In connection with the buffer tank of the station 4, which is a storage station within the meaning of the present invention, it is clear that the flow rate of the mixed waste between two adjacent stations is substantially constant, but the mixed waste is conveyed to the next station at a higher rate. than the speed at which it was conveyed to the previous station, whereby the particles of the mixed waste stream at the point of transfer to the transport path to the next station are accelerated. Also, intermediate conveying elements, such as vibration elements, can operate at a speed that is selected according to this acceleration process. The basic principle is the unification and acceleration of the material flow in order to achieve optimal separation of pollutants. This can be achieved by reducing the material flow density by means of the above particle acceleration.

* · ······················································· I · · · · ················

It should be noted here that the auger worms used in some stations ensure the homogeneity of the material flow. Moisture and impurities are present in the mixed waste material so that the individual particles tend to stick together. Furthermore, the particles often adhere to one another, for example due to the sharp edges of the metal particles.

Both the bonded and intercepted particles are detached in the loosening augers.

In connection with FIG. IC, the paper separation (station 7) is shown schematically. In this process step, primarily the attached paper component of the mixed plastic is separated. For this purpose, paper mills into which the material falls through a cyclone separator are intended. Inside the paper mill body, the fraction is thrown by the rotor by centrifugal force towards the screen. By means of a specially adapted paper separator, as described, for example, in German patent application 196 16 623.3, considerable friction develops. The paper is pulled into small pieces, it passes through the sieve body to the other side, where it is sucked out by means of a paper suction machine and then passes through a compacting screw into the container. The much stiffer plastic remains on the inside of the screen body, where it is conveyed to the next buffer tank (station 8) as described in connection with FIG. The friction heat also serves to dry the fraction. Both fractions are separated from the driving air by means of a cyclone separator. The drive air is cleaned and discharged in the activated carbon filter device (such as station 17). By means of a suction head, a vacuum fan is applied to the buffer reservoir to prevent blockage. Further separation of heavy non-magnetic particles within the downstream separator (station 9) is described, which is described in connection with FIG. 5. The suction power in the gravity trap is set so that heavy particles fall down. The lighter fraction is entrained in an air stream and transported to the next process step. After passing through the second gravity separator, the plastic fraction contains 0 <0 9 0 0 «V ·

0 000 0990

0 09 90 000 00 0

0000 000 9000

00 090 40 00 9 «average ash content, ie the proportion of inert substances (residue after ignition) less than 4,5%.

The composite plastics are compressed in one or more agglomerators connected in parallel or in parallel. compactors of known type (station 10.). Accordingly, the plastics are milled to a specified grain size of, for example, 1.0 cm (station 11). The mixed plastic is also conveyed pneumatically to the agglomerators. The filling height is controlled by means of two vibration limit switches or an optical sensor. In the hopper of the agglomerator, a continuous supply of material to the feed auger is ensured by means of stirring shafts. In the agglomerator, the mixed plastic is treated to a bulk material with a specific weight of more than 300g / l. Details of the agglomerator are described with reference to FIG.

5.

After this step, the pressure blower transports the compacted material for additional grinding to smaller particles (station 11). These mills have a nozzle which, by supplying a mixture of water and air, cools the grinding apparatus to avoid excessive plasticization of the material. This avoids clogging due to the material's high heating. Between the stations 10.) and 11.) the above-mentioned central pressure fan is used for transport. It may be advantageous to feed the water-air mixture in the form of a mist through the nozzle into the conduit between the stations 10.) and 11.) in order to plasticize the surface of the material coming from the compactor and to prevent it from sticking together. The actual cooling process is carried out in the station 11.), where, due to the high velocities in the mill, the cube alternating the curing-slicing-curing processes ... until the final grain size of the material is achieved. The moisture content is controlled so that the agglomerate does not contain any residual water. This means approximately 20 to 401 water per 500 kg plastic material.

As shown in Fig. IE, the weighing (station 12) of the treated agglomerate is then carried out using a flow-through known in the art which appears to be advantageous in connection with pneumatic conveying of material. Subsequently, the magnetic metals are separated again (station 13). The agglomerate passes through a rotating slanted sieve drum. I β · I · β · · · * · »· * *» »* * I I I I I I 9

9 9 9 9 9 9 9 9 9 9 • «« · · 9 9 9 9 9 9 9 9 (station 14.), with all particles having a diameter of less than 10 mm falling through the sieve. By means of a pressure fan, the material infiltrated into the hopper is transported to the silos for storing the finished product. Particles that do not fall through the sieve drum fall out in the direction of the slant. This material is returned to the buffer tank (station 6) which is intended for the material prior to agglomeration. Quality control (station 15.) ensures compliance with the directives concerning specific values of agglomerate for raw material use. In the storage units (station 16.) are placed dust filters and vibration equipment, the material is unloaded by means of a horizontal screw conveyor into tank trucks. The respective control device (station 18) controls the drive and supervision of the individual components of the device and shuts down, for example, when the critical equipment limits are reached in front of the station at which the failure occurred.

The process is carried out by means of process air flow, the air being discharged only after cleaning (station 17.).

Fig. 2 shows a buffer tank in which material is collected from all crushers. The capacity of such a buffer tank is, for example, 40m ³ . The container consists of a container 200, into which ground ground waste is conveyed through the opening 210 by means of a chain scraper conveyor, which is schematically shown above the opening 210. The ground material then falls to the bottom of the container 200, in which six parallel discharge screws 230 are installed. They cover the entire surface of the bottom of the container 200 and act to prevent bridge formation in the ground material. Thus, the container 200 may be completely emptied if necessary. Against the discharge screws 230, a forward screw 240 is rotated 90 ° to ensure uniform loading of the chain scraper conveyor. The speed of the forward auger 240 is slightly lower than the speed of the augers 230, based on the amount of material being conveyed, the speed of the forward auger 240 is 16 min ¹ , while the speed of one auger 230 is 21 min ¹ .

FIG. 3 shows a buffer tank in which the plastic fraction is collected. It also consists of a container 300 which, however, is tapered or conical in order to avoid a bridge effect within the container. trapezoid extended towards the bottom - not shown in the picture. The filling level is monitored by means of vibrating indicators behind the inspection window 360. To this end, the two inspection windows 350 allow an optical inspection of the filling level. The plastic fraction material enters the container through an opening 310. The pressure fan 340 exerts a vacuum in the container 300, thereby preventing dusting. Exhaust air containing plastic particles is fed to the auger worms 330, which also operate under vacuum. Further, dispensing screws (not shown) are disposed within vessel 300 to convey the material to the leaking augers 330.

Fig. 4 shows a longitudinal cross-section through a single gravity separator according to the present invention. In this case, the mass flow 5 in the screw conveyor 450 is wormed and loosened by the screw helix 451, and the material flow thus prepared is fed through an inlet throat 410 whose longitudinal axis forms an angle of approximately 45 ° with the longitudinal axis of the vertically extending separation tube 425. The size of the angle may be variable to vary the rate of entry of the material mixture into the air stream. The air flow in the separation tube 425 is directed vertically upward and is generated by a pressure blower (not shown).

As it enters the separation tube 425, the material mixture strikes an air flow, with the individual fluidized portions of the mixture exerting an upward force. Particles having a specific gravity lower than that predetermined are carried upwards by air. These light particles are then discharged as material flow 5 for further processing.

Heavier particles cannot be carried upwards due to higher gravitational force, they fall down and are discharged as material flow 4.

Such a gravity separator is, for example, at the station 6.

Fig. 5 shows a longitudinal cross-section of a separator which is preferred, e.g. located at station 9. At this separator, the separator is a flow In the same way, in the screw conveyor 450, the screw helix 451 is fluidized and loosened and then fed through the feed tube 410 to the separation tube 420. By analogy to the separators in FIG. 4, heavier particles are discharged by material flow. lines 421, 422 and 423 are routed as material flow 5 for further processing.

A pressure blower 430 generates a vertical upward air flow in the tube 423. This creates a negative pressure that generates air flow in the conduits 422, 421 and 420 in the above direction.

Furthermore, there are variable opening flaps 440 that allow air flow rate control during separation. When the flaps 440 are open, the outside air is sucked in, reducing the airflow speed. Due to the suction acting here, the particles cannot in any case escape through the flaps and cause material loss.

In both embodiments, the screw conveyors 450 are sealed against the outside air so that it cannot enter uncontrolledly into the separator system.

At this point it should be noted that in addition to the gravity separators shown in Figs. 4 and 5, other geometrical configurations are possible, furthermore, the gravity separators according to the invention can be fitted at any desired location, for example in particular the gravity separators of Fig. 5. station 9 as described above. Gravity separators have been described in the mixed waste treatment process to clarify the preferred areas of use, but may also be applied in other areas where separation of individual particles by specific gravity is to be performed.

Furthermore, it should be noted that due to the high efficiency of the gravity separators according to the invention it is also possible to omit the above described process d) separating the magnetic metal particles, which is normally carried out by means of magnetic separators, unless

· Additional separation of the magnetic parts is required, or the process d) may be downstream of the gravitational separators in the above-described order, whereby the process of d) separation of the magnetic metal particles may be more efficient from the material flow 4 than from the material flow 5 .

Giant. 6 shows a longitudinal section through an agglomerator. In a real plant, for example, six agglomerators are connected in parallel. From the buffer container of FIG. 3, the mixed plastic is pneumatically fed to the six agglomerators. Two vibration limit switches regulate the optimum filling height. In the hopper 500, the mixing spirals 510 provide a continuous supply to the feed screw 520. The feed screw speed 520 is adjustable, for example in the range from 16.8 min ^-1 to 100 min ^-1 . The material conveyed by the feed worm is processed in a known manner between two discs housed in the agglomerator body 530, which are provided with replaceable kneading bars. One of the disks acts as a stator and the other as a rotor. The distance between the stator and rotor disc can be adjusted by means of an axially displaceable bearing located in the body of the agglomerator 530. Both discs are equipped with cooling to prevent heat from being exposed to the material. For this purpose, openings are directed radially to the center of the disks through which cooling water can pass in a controlled manner so that the temperatures of the disks do not move in an area in which the plastics become very soft and can seal the disks. The cooling water temperature should not exceed 40 ° C.

The features of the invention disclosed in the foregoing description, in the drawing and in the claims may be essential to the practice of the invention both individually and in any combination.

Claims (16)

PATENT CLAIMS 1. A process for treating mixed waste according to the invention in a continuous mechanical dry waste treatment plant comprising a plurality of successive processing stations connected to each other by at least one conveyor path comprising at least the following steps in the order of metal separation, pneumatic sorting and paper removal. further steps may or may not be inserted immediately therefrom, characterized in that the raw material flow, upon transfer to the last conveyor path before the processing station, accelerates, so that the average actual particle flow rate of the raw material flow on the last conveyor path and thereby immediately before entering the metal separating processing station is lower than before entering the pneumatic sorting processing station ndsichtung (see changed sheet) and this is again below the average speed before entering the paper removal station. Method according to claim 1, characterized in that the mixed waste flow between two adjacent stations is conveyed at a substantially constant speed on the current transport route. Method according to claim 1 or 2, characterized in that a stock of possibly treated material will be deposited for at least one of the stations. Process for the treatment of mixed wastes according to one of claims 1 to 3, consisting mainly of plastics, paper-plastic sandwiches, glass, metal, paper, cardboard and other impurities, for the continuous operation of a waste treatment plant, with the steps of (a) crushing mixed waste (b) intermediate deposition of crushed mixed waste (c) uniform transport of interposed mixed waste (d) separation of magnetic metal particles 9 99 99 9 9 9 9 «· · ··· 9 9 9 9 9 9 (e) separation of non-magnetic particles from materials whose specific gravity exceeds an adjustable minimum specific gravity (f) of separation of paper, such as paper-plastic sandwich materials (g) and (h) agglomerating the plastic fraction. Method according to claim 4, characterized in that after step (g), step (e) is newly performed. Method according to claim 4 or 5, characterized in that (i) the agglomerated plastic is crushed to a stable grain size. Method according to claim 6, characterized in that after step (i), step (d) is newly performed. Method according to one of Claims 4 to 7, characterized in that the material to be processed is conveyed pneumatically. Apparatus for carrying out the process according to one of claims 1 to 8, comprising: (a) at least one shredder for crushing mixed waste; (b) a first buffer reservoir serving as the first buffer station to which the crushed mixed waste is conveyed from each of the crushers, the buffer reservoir comprising a device for uniformly supplying the weighing conveyor; (c) at least one magnetic separator; (d) at least one device for separating non-magnetic particles from substances of a specific weight that exceeds an adjustable lowest specific gravity; (e) at least one paper removal device, for example, of paper-plastic sandwich materials; (f) a second buffer container, serving as a second buffer station, in which the plastic fraction is collected from all paper removal devices; and (g) at least one agglomerator for agglomerating the plastic fraction. Device according to claim 8, characterized in that at least one non-magnetic particle separation device having a specific gravity is assigned to the buffer reservoir into which the plastic fraction is collected. higher than the adjustable minimum specific weight. Apparatus according to claim 9 or 10, characterized in that the at least one agglomerator is connected to a device for treating the agglomerates to a fixed grain size. Device according to claim 11, characterized in that at least one further magnetic separator is provided to which the treated agglomerate is conveyed. A buffer tank for a device operating according to one of claims 1 to 8, comprising a container (200) with at least one opening (210) in the upper part of the container (200) for loading the intermediate material and at least one discharge opening (220) for a material, characterized in that a plurality of discharge screws (230) are disposed at the bottom of the container, the screws being arranged to extend the entire surface of the bottom of the container (200) and have at least one forward screw ( 240), which transports the raw material in a homogenized manner over at least a portion of the discharge screw (230) so that a homogenized material flow is discharged through the at least one discharge opening (220). A buffer tank according to claim 13, characterized in that the discharge screws operate in a different sense of rotation. A buffer tank according to claim 13, characterized in that the discharge screws (230) are arranged parallel to each other and the forward screw (240) is rotated 90 ° relative to the discharge screws. A buffer tank for a device operating according to claims 1 to 8, comprising a container (300) with at least one opening (310) at the top of the container (300) for loading the intermittent material and at least one discharge opening (320) for a material, characterized in that it has at least one vacuum worm (330) for the material to be stored, and that at least one worm (330) is supplied with air from the container (300) to the at least one worm (330). Π. The buffer reservoir according to claim 16, characterized in that the container (300) widens conically or trapezoidly towards the bottom.