EP0579966A1 - Process and apparatus for separating non-magnetic metals from a mixture - Google Patents

Abstract

A method for separating non-magnetisable metals from a mixture by means of an eddy current makes it possible to separate non-ferrous metals, especially small and/or light particles and, in particular, predominantly flat articles of such metals, if the non-ferrous metals contained in the mixture are acted upon on at least three sides by alternating magnetic fields. An apparatus suitable for this purpose has a combination-type alternating magnetic field generator (1) in the mixture feed, this generator consisting of a magnetic rotor (2) and a magnetic-disc rotor (3) comprising at least two mutually parallel vertical discs driven in rotation. <IMAGE>

Description

The invention relates to a method and a device for separating non-magnetizable metals from a mixture by means of eddy current.

An alternating magnetic field is generated for eddy current separation of non-magnetisable, electrically highly conductive metals, for example - as has become known from German Patent 3,817,003 - by means of an inductor or by means of a magnet rotor. The feed material - hereinafter also referred to as a solid mixture or mixture - can be guided over the poles of the alternating magnetic field generator, for example on a conveyor belt or in free fall. Eddy currents are induced in the electrically highly conductive constituents of the solid mixture to be separated, which build up their own magnetic fields opposing the generating field and accelerate these components relative to the other constituents of the solid mixture due to the resulting repulsive electromagnetic forces. Eddy current separation can be used to separate non-ferromagnetic, highly electrically conductive materials, such as aluminum and copper, from non-ferrous solid mixtures and non-ferrous metal / non-metal solid mixtures, such as automobile shredder rubble, electronic scrap and the like. If this Solids mixtures contain ferromagnetic parts, the eddy current separation should be preceded by a magnetic separation in order to remove ferromagnetic parts beforehand. In addition, other sorting and classifying stages are expediently preceded by the eddy current separation, because the greatest possible pre-enrichment and fractionation of the solid mixture added have a positive effect on the separation success and the throughput of the eddy current separator.

In the known NE separator, a rapidly rotating rotor, equipped with permanent magnets and adjustable in its position, is arranged eccentrically inside an outer drum wrapped in a conveyor belt. The solid mixture fed via the conveyor belt is flooded by the full flow of the magnetic field when the material discharge zone is reached. Because exactly in this area the magnetic rotor has been set so that when the material to be separated falls or slides due to gravity, the combination of the mechanical ejection forces with the latest possible forces of the magnetic field for the non-ferrous metals is the greatest Deflection of the throwing parabola and thus a targeted separation from the other mixture components results. The non-ferrous metals deflected on a wide throwing parabola fall in a defined manner into a collecting container which is set up at a distance from the collecting point for the other mixture components. The separation into valuable non-ferrous metal components and other components is supported by means of a separation apex which can be adjusted with its apex in a substantially horizontal direction. The latter components fall down essentially without deflection and, viewed in the transport direction, reach an area in front of the parting parting.

A known from German Offenlegungsschrift 38 10 715 Instead of a rotor equipped with permanent magnets or an inductor, eddy current separators have two mutually parallel, vertical, rotationally driven disks, which are fitted with magnets of alternating polarity. The solid mixture to be separated enters the upper middle region between the disks via a feed device. The magnets on the rotating disks induce eddy currents with a high field density in the solid mixture entering the space between the disks, which interact with the magnetic field of the rotating disks. With this eddy current separator, which can also have several disks arranged at a distance from one another, it is possible to utilize the different conductivity of the mixture components of the solid mixture, e.g. B. non-magnetic steels, which have an austenitic or austenitic / ferritic structure and whose electrical conductivity is low, from those components whose conductivity is good, such as copper. In addition to electrical conductivity, density also has a significant influence on eddy current separation. The deflectability of an electrical conductor results from the quotient of electrical conductivity and its density. Thus, while components made of stainless steel reach the outlet opening assigned to them without being significantly influenced by the magnetic field of the rotating disks, copper parts fall radially further outwards due to the magnetic interaction achieved and thus separate from the electrically poorly conductive parts. The separation of the mixture constituents is promoted by an adjustable separating apex which plunges between the throwing parabolas.

As has been shown, they hang with the well-known NE separators separation results to be achieved depend essentially on the grain shape and size of the constituents of the solid mixture. In addition, problems often arise in the alternating field due to the shape and location of the NE particles. This applies above all to small, flat, approximately 3 cm in diameter and approx. 2 mm thick non-ferrous particles, which - depending on their position - behave very differently in the alternating field and sometimes do not react at all or only very weakly.

The invention has for its object to provide a method and an apparatus which allow in particular small and flat non-ferrous metals to be separated from a solid mixture.

In a method, this object is achieved in that the mixture is exposed to alternating magnetic fields from at least three directions. With this at least three-sided exposure, which can be carried out in the course of the separation process, the non-ferrous metals are influenced surprisingly and strongly selectively. As has been confirmed by numerous tests, a combination of an eddy current effect with alternating magnetic fields that influences the non-ferrous particles both from below and from the side, especially the problematic flat non-ferrous metals in the course of the separation process, leads to such a favorable position Brought alternating magnetic field that even aluminum and magnesium can be separated cleanly, although the characteristic of the deflection characteristic of electrical conductivity and density with these two materials is almost the same size; Due to the combined alternating current from below and from the sides, aluminum can be accelerated to a significantly different trajectory than magnesium. It can be done in this way Basically separate all types of material, especially copper and nickel.

According to the invention, a device for separating non-magnetisable metals from a mixture by means of eddy current has in the mixture feeder a combination alternating magnetic field generator consisting of a magnetic rotor - alternatively an inductor - and a magnetic disc rotor comprising at least two parallel, vertical, rotationally driven discs. Disks arranged in parallel are also to be understood to mean, for example, advantageously disks designed like pots or bowls. The invention leads to the surprising result, which has been confirmed by tests, that when a magnetic rotor and a magnetic disk rotor are used in combination, an optimized separation result can be achieved, in particular with regard to the problematic flat components of a solid mixture. Because due to the alternating eddy current effect of the combination alternating magnetic field generator according to the invention, in which the magnetic rotor or the inductor, which can be arranged eccentrically and adjustable advantageously with respect to the magnetic disk rotor, influences the non-ferrous particles from below and the magnetic disk rotor from the sides, the flat parts in a position favorable to the alternating field. This also applies if the two rotors or the magnetic disk rotor and the inductor are spatially separated from one another in the mixture feed and the mixture is thus exposed to the alternating magnetic fields from at least three directions in the course of the separation process, namely once the magnetic disk rotor and then the magnetic rotor or inductor, and vice versa. "Mixture supply" is also understood to mean the version in which the solid mixture is first applied to the magnetic rotor or the inductor in separate work steps and then to the magnetic disk rotor - or vice versa - ie a discontinuous or gradual feeding of the solid mixture.

Although the eddy current generators - as described - can be spatially separated from one another, it is nevertheless proposed according to a preferred embodiment of the invention that the magnet rotor or the inductor and the magnet disk rotor are built into one another coaxially, the magnet rotor or the inductor bridging the axial distance between the disks . In terms of machines, the two eddy current generators thus represent a unit and thus a completely new concept for an alternating magnetic field generator, namely a combination alternating magnetic field generator, in which the alternating eddy current effects combine to form a synergistic separation effect. For example, while the magnetic rotor, which is arranged concentrically or eccentrically to the two rotor disks, the drum of which forms a hub of the combination alternating magnetic field generator, lifts the non-ferrous particles of the solid mixture, the magnetic fields of the magnetic disk rotor that influence the non-ferrous particles from the sides exert an additional impulse on the non-ferrous particles, with the result that different discharge parabolas are defined for the various recyclables to be separated.

The greater spreading of the throwing parabolas of the different non-ferrous metals is also favored by the interaction of three overlapping and reinforcing fall curves or throwing parabolas, namely a throwing parabola independent of the magnetic field and determined by the speed, for example, of a conveyor belt feeding the solid mixture, and the throwing parabolas due to the Magnet rotor or the inductor and the magnetic disk rotor. The inductor can be switched on if necessary, which can contribute to energy savings.

If the magnetic rotor and the magnetic disk rotor have a common axis of rotation, only one drive is required. Nevertheless, it is within the scope of the invention that the two rotors are driven independently of one another and possibly in opposite directions, so that an individual speed control, e.g. via frequency converter. The rotor speeds, which are already designed to be lower than usual due to the combined action of the eddy current according to the material and have no adverse effect on the separation result, and the lower inertial forces thus achieved can be further reduced by a targeted speed control.

The magnetic rotor or the inductor and the magnetic disk rotor, i.e. the combination alternating magnetic field generator is arranged in an H-shaped housing made of an antimagnetic and electrically poorly conductive material, adapted to the contour of the combination device. The expression "poor electrical conductivity" takes into account that, according to scientific understanding, all materials are electrically conductive; a distinction is only made between better or poorer conductive materials, the conductivity of the latter practically going to zero (cf. page 522 from "Taschenbuch Elektrotechnik", vol. 1, Carl Hanser Verlag). The housing completely encapsulates the rotors from the outside.

If the housing is advantageously mounted such that it can rotate and is designed as a front, driven deflection drum for an endless conveyor belt that feeds the solid mixture between the disks of the magnetic disk rotor, the hub of the housing receiving the combined machine unit simultaneously forms the outer drum of the magnetic rotor and the deflection drum for the endless conveyor belt.

The combination alternating magnetic field generator and / or the deflection drum can be horizontally and / or vertically adjustable. In the case of a combination alternating magnetic field generator rotating about a common axis of rotation, the deflection drum, i.e. the housing serving to deflect the conveyor belt at the same time, can in any case be adjusted in order to achieve an optimal position of the conveyor belt in relation to the two rotors. The setting options are expanded if a rear guide roller deflecting the conveyor belt is pivotably mounted.

If, according to a further embodiment of the invention, the housing of the combination alternating magnetic field generator is stationary, the conveyor belt loops around at least two deflection or conveyor rollers and engages with at least its upper run between the disks of the magnetic disk rotor and runs above the central section of the H-shaped housing variably adjust the movement or orbit of the conveyor belt feeding the solid mixture to the two rotors enclosed by the stationary housing by changing the position of the deflection or guide rollers and expanding the number of rollers. Furthermore, it is also possible to provide a feed of the solid mixture below the combination magnetic field generator.

Fig. 1

eine Wirbelstromscheidevorrichtung aus einem Magnetrotor und einem Magnetscheibenrotor als Maschineneinheit (Kombi-Wechselmagnetfelderzeuger), in schematischem Längsschnitt;

Fig. 2

den Kombi-Wechselmagnetfelderzeuger gemäß Fig. 1 im Querschnitt;

Fig. 3

eine Variante eines erfindungsgemäßen Kombi-Wechselmagnetfelderzeugers, in schematischer Seitenansicht;

Fig. 4

eine weitere Ausführungsform eines erfindungsgemäßen Kombi-Wechselmagnetfelderzeugers, in schematischer Seitenansicht;

Fig. 5

eine Wirbelstromscheidevorrichtung, bei der ein Kombi-Wechselmagnetfelderzeuger aus einem Magnetscheibenrotor und einem Induktor besteht, in schematischem Längsschnitt; und

Fig. 6

eine Wirbelstromscheidevorrichtung gemäß Fig. 1, mit demgegenüber allerdings exzentrisch angeordneten Magnetrotor.

Further features and advantages of the invention result from the claims and the following description, in which some exemplary embodiments of the subject matter of the invention are explained in more detail. Show it:

Fig. 1

an eddy current separating device from a magnetic rotor and a magnetic disk rotor as a machine unit (combined alternating magnetic field generator), in a schematic longitudinal section;

Fig. 2

the combi-alternating magnetic field generator according to Figure 1 in cross section.

Fig. 3

a variant of a combination alternating magnetic field generator according to the invention, in a schematic side view;

Fig. 4

a further embodiment of a combination alternating magnetic field generator according to the invention, in a schematic side view;

Fig. 5

an eddy current separating device, in which a combination alternating magnetic field generator consists of a magnetic disk rotor and an inductor, in a schematic longitudinal section; and

Fig. 6

an eddy current separating device according to FIG. 1, with the magnetic rotor, however, arranged eccentrically.

A combination alternating magnetic field generator 1 shown in FIG. 1 consists of a magnet rotor 2 and a disk magnet rotor 3 which has two vertical, rotationally driven disks 4 which are arranged at a distance from one another and in which flat permanent magnets 5 are embedded to generate the effective magnetic field (cf. . 2). The magnet rotor 2 arranged in a drum 6 is also provided with rows of permanent magnets 7 fastened in alternating north-south polarity in the base body. The magnetic rotor 2 and the magnetic disk rotor 3 are built into one another, the magnetic rotor 2 being arranged concentrically with respect to the disks 4 and bridging the axial distance between the disks 4 compared to a smaller diameter (cf. FIG. 2). The permanent magnets 5 of the magnetic disk rotor 3 face each other Arranged sides of the disks 4 and distributed approximately from the magnetic rotor 2 to the outer periphery of the disks 4 in these.

The magnet rotor 2 and the magnetic disk rotor 3 are arranged in a housing 8 which is adapted to the cross-sectionally H-shaped contour of the combination alternating magnetic field generator 1, the hub-like middle part of which accommodates the magnet rotor 2 and simultaneously serves as a front deflection drum for a second rear deflection drum 9 guided endless conveyor belt 11 serving drum 6 forms. 2, the magnetic rotor 2 and the magnetic disk rotor 3 have a common axis of rotation 12, which is driven at high speed by a motor (not shown) and which is supported in roller bearings 13. The housing 8 is also stored in roller bearings 14 and is driven by a motor, not shown, at a low, variable speed, so that the conveyor belt 11 wrapping around the drum 6 of the driven housing 8 at a speed of optionally 0.2 to 1.8 m / s revolves.

The combination alternating magnetic field generator 200 shown in FIG. 6 differs from the previously described embodiment only in that the magnetic rotor 39 is arranged eccentrically and can be pivoted in the direction of the arrow 41; it can be adjusted exactly to the discharge point of the solid mixture. In the combination alternating magnetic field generator 300 according to FIG. 5, a swivel-mounted inductor 38 is located in the drum 6 instead of a magnetic rotor.

In order to separate non-ferrous metals, a mixture of solids is placed onto the conveyor belt from a low height, for example from a vibration channel (not shown) inclined in the direction of conveyance 15 of the conveyor belt 11.

The solids mixture, which has already been uniform in height and width on the vibrating trough during transport, is further homogenized and distributed due to a higher speed of the conveyor belt 11 than the vibrating trough, so that the layer height of the solid mixture is further reduced and the mixture components 16 form an essentially single-layer layer form, as this is extremely exaggerated in the figures for reasons of clarity. As soon as the mixture components 16 reach the effective range of the eddy currents generated by the two rotors 2, 3 or the inductor 38 and the magnetic disk rotor 3, they are influenced by magnetic fields from three directions. 2, the magnetic field of the magnetic rotor 2 - or inductor 38 - acting from below on the mixture components 16 is indicated by arrows 17 and the magnetic fields of the magnetic disk rotor 3 acting on the mixture components 16 from two sides are identified by arrows 18.

As shown in FIG. 2, the force of the eddy currents of the supporting magnetic fields 17, 18 of the magnetic rotor 2 and the magnetic disk rotor 3 for the non-ferrous metals corresponding to the throwing parabolas 19 and 21 results from the fully effective force of the eddy currents in the material discharge area of the combination alternating magnetic field generator 1 a wide deflection of the curve so that these components can be collected separately from one another and from heavy metals falling according to the throwing parabolas 22 essentially without deflection in different collecting chambers 23, 24, 25. The collection in the collecting chambers 23 to 25 assigned to the individual separated components is supported by the dividing plates 26 facing the throwing parabolas 19 or 21 and 22.

When executing a combination magnetic field generator 100 3, the housing 8 encapsulating the magnet rotor 2 and the magnetic disk rotor 3 cannot be driven, that is to say it can be made stationary. The conveyor belt 11 loops around a driven front head roller 27 and a rear deflection or guide roller 28, and its runs run in the space between the two disks of the magnetic disk rotor 3, the magnet rotor 2 being located between the upper and the lower run. With this version, the conveyor belt can be variably positioned in a simple manner.

The combination alternating magnetic field generator 100 shown in FIG. 4 is assigned a conveyor belt 11 which is guided over three guide rollers 29 and 31, 32 which deflect it in a triangular manner. In this embodiment variant, only the horizontal belt section extends between the disks of the magnetic disk rotor 3, and the guide roller 29, which is arranged downstream of the combination alternating magnetic field generator 100 in the conveying direction 15 and is designed as a top roller, can be brought close to the magnetic disk rotor 3 due to its small diameter, which results in the discharge the mixture components 16 fed by the conveyor belt 11 favors.

So that the position of the conveyor belt or the mixture feed in relation to the combination alternating magnetic field generator 1, 100, 200, 300 can be optimized, according to the double arrows 37 shown in the figures, the combination magnetic field generator 1, 100, 200, 300 and / or the deflection or guide rollers 9, 28 are horizontally and / or vertically adjustable.

Claims (16)

Process for separating non-magnetisable metals from a mixture by means of eddy currents, characterized in that the mixture is exposed to alternating magnetic fields from at least three directions. Device for separating non-magnetizable metals from a mixture by means of eddy current, characterized by a combination alternating magnetic field generator (1, 100) consisting of a magnetic rotor (2) and an at least two parallel, vertical, rotationally driven disks (4) comprising magnetic disk rotor (3) Mixture supply. Device for separating non-magnetisable metals from a mixture by means of eddy current, characterized by a combination alternating magnetic field generator (1, 100) consisting of an inductor (38) and an at least two parallel, vertical, rotationally driven disks (4) comprising magnetic disk rotor (3) Mixture supply. Apparatus according to claim 2 or 3, characterized in that the magnetic rotor (2) or the inductor (38) and the magnetic disc rotor (3) are built into one another coaxially and the magnetic rotor (2) the axial one Distance between the discs (4) of the magnetic disc rotor (3) bridges. Apparatus according to claim 4, characterized in that the diameter of the magnetic rotor (2) is smaller than that of the magnetic disk rotor (3). Apparatus according to claim 3 or 4, characterized in that the inductor (38) is pivotally mounted. Apparatus according to claim 2 or 3, characterized in that the magnetic rotor (2) or the inductor (38) is arranged eccentrically with respect to the magnetic disk rotor (3). Device according to one or more of claims 2 to 7, characterized in that the disks (4) of the magnetic disk rotor (3) are cup-shaped. Device according to one or more of claims 2, 4 or 5 and 7 or 8, characterized in that the magnetic rotor (2) and the magnetic disc rotor (3) are driven independently of one another. Device according to one or more of claims 2, 4 or 5 and 7 to 9, characterized in that the magnetic rotor (2) and the magnetic disc rotor (3) have a common axis of rotation (12). Apparatus according to claim 3 or 10, characterized in that the magnetic rotor (2) or the inductor (38) and the magnetic disk rotor (3) in a housing which is H-shaped in cross section and which is adapted to the contour of the combined alternating magnetic field generator (1, 100) ( 8th) are arranged from an antimagnetic and electrically poorly conductive material. Apparatus according to claim 11, characterized in that the housing (8) is rotatably mounted and is designed as a front, driven deflection drum (6) for an endless conveyor belt (11) guiding the solid mixture between the disks (4) of the magnetic disk rotor (3). Apparatus according to claim 11 or 12, characterized in that the combination alternating magnetic field generator (1, 100) and / or the deflection or guide drum (9, 29, 31, 32, 28) are horizontally and / or vertically adjustable. Apparatus according to claim 12 or 13, characterized in that a rear guide roller (9, 28) deflecting the conveyor belt (11) is pivotably mounted. Device according to one or more of claims 2 to 11, 13 or 14, characterized in that the housing (8) of the combination alternating magnetic field generator (100) is stationary, the conveyor belt (11) has at least two deflection or guide rollers (27, 28 or 29, 31, 32) and engages with at least its upper run between the disks (4) of the magnetic disk rotor (3) and extends above the central section of the H-shaped housing (8). Apparatus according to claim 15, characterized by a triangular guide of the conveyor belt (11), at least one triangular side running between the disks (4) above the magnetic rotor (2) or inductor (38).

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