Separation of the constituents of a metalliferous mixture

Abstract

A device for separating a metalliferous, lumpy mixture, with a conveyor belt and with a rotating drum in which a fixed magnet system with at least one magnet line is arranged. The separating effect of the device is improved and its complexity is reduced where it is provided that the magnets of the at least one magnet line are arranged such that their poles have the sequence NS SN or SN NS in the circumferential direction, as a result of which the ratio of the maximum radial magnetic flux density to the maximum tangential magnetic flux density on the belt surface, facing the material, in the region of the magnet system is greater than one and, owing to this, the electrically conductive particles are separated out into the first partial stream by radial force action (repulsion).

Claims

1. A device for separating a metalliferous mixture of materials, comprising: a conveyor belt configured to convey the mixture of materials; a rotating drum supporting the conveyor belt; a fixed magnet system arranged in the drum, such that the magnet system does not rotate as the drum rotates where the magnet system includes at least one magnet line in which magnets are arranged so that their poles have a sequence NS SN or a sequence SN NS in a direction that is circumferential relative to the drum, with a result that a ratio of the maximum radial magnetic flux density to a maximum tangential magnetic flux density on a surface of the belt facing the materials in a region of the magnet system is greater than one; such that non-ferrous metals in the mixture of materials are separated by a splitter into a partial stream by force action, due to a formation of eddy currents in electrically conductive particles in the mixture of materials.

2. The device of claim 1, wherein the magnet system consists of precisely one magnet line.

3. The device of claim 1, wherein a ferromagnetic bar is positioned between the magnets of the magnet line.

4. The device of claim 1, wherein the magnet system can be rotated about the center of the drum.

5. The device of claim 1, wherein the magnet system includes an electromagnet arrangement or a superconducting magnet arrangement.

6. The device of claim 1, wherein the magnet system has an extension, and the magnetic poles thereof have a lower magnetic flux density on the belt surface than that of the magnet system.

7. The device of claim 6, wherein the extension of the magnet system has a multi-row design.

8. The device of claim 7, wherein the extension of the magnet system can be rotated about the center of the drum.

9. The device of claim 7, wherein the extension of the magnet system includes an electromagnet arrangement or a superconducting magnet arrangement.

10. The device of claim 1, wherein the conveyor belt has a rough or profiled design.

11. The device of claim 1, wherein a speed of the conveyor belt speed is over 2 m/s.

12. The device of claim 11, wherein the speed of the conveyor belt is over 4 m/s.

13. The device of claim 11, wherein the speed of the conveyor belt is over 5 m/s.

14. A method for separating a metalliferous mixture of materials, comprising: separating a first partial stream of non-ferrous metals from the mixture of materials by eddy-current sorting with a device according to claim 1, by way of a splitter; failing to influence a second partial stream of non-metals; and separating a third partial stream of weakly magnetic particles from the mixture of materials by magnetic force action of a magnet system of the device according to claim 1, by way of a splitter.

15. A method for separating a metalliferous mixture of materials, comprising: separating a first partial stream of non-ferrous metals from the mixture of materials by eddy-current sorting with a device according to claim 7, by way of a splitter; failing to influence a second partial stream of non-metals; and separating a third partial stream of weakly magnetic particles from the mixture of materials by magnetic force action of an extension of the magnet system of the device according to claim 7, by way of a splitter.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) The invention will be explained in more detail below on the basis of the drawing, in which:

(2) FIG. 1 shows the device according to the invention with a fixed magnet system and an extension of the magnet system, and the two splitters for sorting the feed mixture into the partial streams A, B and C,

(3) FIG. 2 schematically shows the magnet system, the magnetic field lines, and the forces of the device according to the invention that act on an electrically conductive particle,

(4) FIG. 3 shows the belt drum and three trajectories, recorded by means of a camera system, from a test series carried out with identical electrically conductive particles.

DETAILED DESCRIPTION

(5) According to FIG. 1, the device consists of a rotating drum 1 with a conveyor belt 2, in which drum the fixed magnet system 3 and the extension 4 are arranged. Here, the surface of the conveyor belt 2 is, as already mentioned, preferably not of smooth design, but of profiled design. However, the extension 4 of the magnet system 3 does not amount to a prerequisite for the function according to the invention, but constitutes a configuration. A mixture 5 obtained from metal recycling, for example, is fed via the drum 1, wherein said mixture consists inter alia of non-ferrous metals 6 (for example aluminum, copper, lead), weakly magnetic metals 7 (for example VA steel) and non-metals 8 (for example plastic, rubber).

(6) As already described, the required relative speed between the magnet system 3 and the feed mixture 5 is achieved by the high speeds of the conveyor belt 2 of at least 2 m/s, preferably at least 4 m/s, and particularly preferably of at least 5 m/s.

(7) The non-ferrous metals 6 pass into the first partial stream A by way of the splitter 9 owing to the formation of eddy currents during the movement over the magnet system 3 and to the resulting repelling force action on said non-ferrous metals, the non-metals 8 pass into the second partial stream B without being influenced, with the exception of particle-particle interactions, and weakly magnetic metals 7 pass into the third partial stream C by means of the splitter 10 owing to the magnetic force action of the magnet system 3 and of the extension 4.

(8) As already described, in a refinement of the invention, for the purpose of controlling the lift-off point of the non-ferrous metals 6, both the magnet system 3 and the extension 4 thereof are able to be rotated about the center of the belt drum 1 and the magnetic flux density of the extension 4 is, on the belt surface, lower than the magnetic flux density of the magnet system 3.

(9) FIG. 2 schematically shows the device according to the invention, and visible here are the magnet system 3 with a magnet line consisting of two magnet rows 11, which are, in cross section, polarized tangentially with respect to the drum periphery and are opposite one another with like poles, and the ferromagnetic bar 12 which is positioned between the poles, the magnetic field lines 13 of the magnet system 3 and the forces acting on an electrically conductive particle 14 owing to the formation of eddy currents. The region of the magnet system is, as can be seen from the illustrated magnetic lines, approximately twice as long in the direction of movement as the magnet system and can be up to three times as long, the extension 4 (FIG. 1) not being considered in this case.

(10) Clearly visible here is the advantage of the fixed magnet system 3 with a magnet line in comparison with eddy-current separators with a rotating pole wheel, according to which an electrically conductive particle 14 substantially reaches the maximum flux density on the surface of the conveyor belt 2 while, according to the prior art, said particle already experiences a repelling force action even though it has not yet reached the maximum flux density on the surface of the conveyor belt.

(11) FIG. 3 shows the result of a test series which was carried out. Here, as test bodies, use was made of disks with a diameter of 20 mm, a height of 3 mm and an electrical conductivity of 21 MS/m. The speed of the conveyor belt was 3 m/s.

(12) Here, the trajectory of the partial stream D constitutes the ballistics without the use of a magnet system. Whereas for partial stream E a braking magnet system as proposed in DE 10 2012 014 629A1 was used, partial stream F corresponds to the trajectory with use being made of the magnet system 3 of the device according to the invention without an extension 4. The difference between the partial streams E and F can clearly be seen, according to which electrically conductive particles are braked in the case of partial stream E and are radially repelled in the case of partial stream F.

(13) Moreover, the advantage of the use of the device according to the invention can be seen in that, in the case of partial stream F, in contrast with partial stream E, no crossing occurs, and thus also no resulting particle-particle interactions occur, with the partial stream D during the flying phase.

(14) The geometric region for determining the flux density on the belt surface, facing the material, in the region of the magnet system is to be understood as meaning that it is delimited in the circumferential direction by the imaginary extensions of the diameters through the belt drum, which diameters just touch the magnet system in a tangential manner, and in the radial direction by the outer belt surface and one centimeter therebeyond. The respective absolute values of the flux density are to be taken as a result of the at least approximately symmetrical formation of the magnetic field.

(15) Since, according to the invention, the magnets of the at least one magnet line 11 are arranged such that their poles have the sequence NS SN or SN NS in the circumferential direction, as a result of which the ratio of the maximum radial magnetic flux density to the maximum tangential magnetic flux density on the belt surface, facing the material, in the region of the magnet system 3 is greater than one. Owing to this, the electrically conductive particles are separated out into a first partial stream (A) by radial force action (repulsion).

(16) The method according to the invention for separating a metalliferous mixture 5, wherein a first partial stream A of non-ferrous metals 6 is separated out by eddy-current sorting by means of a splitter 9 and a second partial stream B composed of non-metals 8 is not influenced, is characterized in that a third partial stream C composed of weakly magnetic particles 7 is, through the use of a device as explained, and as defined in claims 1 to 7, separated out by magnetic force action of the magnet system 3 or of the extension 4 by way of a splitter 10.

(17) It should also be pointed out that, in the description and the claims, specifications such as largely mean more than half, preferably more than ; thus, in the case of the composition of materials, over 50% by weight, preferably over 80% by weight, and particularly preferably over 95% by weight; that lower region of a reactor, filter, structure or a device or, very generally, an object means the lower half and in particular the lower quarter of the total height, lowermost region means the lowermost quarter and in particular an even smaller part; while middle region means the middle third of the total height. All of these specifications have their generally accepted meaning, applied to the as-intended position of the object being considered.

(18) In the description and the claims, the terms front, rear, top, bottom and so on are used in the generally accepted form and with reference to the object in its normal position of use. That is to say that, in the case of a firearm, the mouth of the barrel is at the front, that the breech or slide is moved toward the rear by the explosion gases, that material on a belt or conveyor belt is moved therewith toward the front, etc.

(19) In the description and the claims, substantially means a deviation of up to 10% of the specified value, if physically possible both downward and upward, otherwise only in the direction that makes sense, 10 consequently being meant for degree specifications (angle and temperature). With designations as in a solvent, the word a is not to be regarded as a numeral but as a pronoun, if nothing to the contrary emerges from the context.

(20) The term combination or combinations, unless specified otherwise, stands for all types of combinations, proceeding from two of the relevant constituent parts up to a multiplicity of such constituent parts, and the term containing also stands for consisting of.

(21) The features and variants specified in the individual configurations and examples may be freely combined with those of the other examples and configurations, and in particular may be used for characterizing the invention in the claims without the forcible inclusion of the other details of the respective configuration or of the respective example.

(22) TABLE-US-00001 List of reference signs: 1 Drum 2 Conveyor belt 3 Magnet system 4 Extension 5 Feed mixture 6 Non-ferrous metals 7 Weakly magnetic particles 8 Non-metals 9 Splitter 1 10 Splitter 2 11 Magnet row(s) 12 Ferromagnetic bar 13 Field lines 14 Electrically conductive particle A First, non-ferrous metal stream B Second, non-metallic stream C Third, weakly metallic stream D Trajectory for ballistics E Trajectory for braking magnet system F Trajectory for magnet system according to the invention