Apparatus and method for sorting

Abstract

An apparatus and a method for sorting, particularly chopped, aluminum scrap by alloy groups are disclosed, in which the aluminum scrap is separated into fractions, fractions of the aluminum scrap are irradiated by at least one neutron source, the gamma radiation that the individual fraction emits due to this neutron irradiation is detected by at least one detector, and based on this, an energy spectrum associated with the respective fraction is generated, based on which energy spectrum a relative ratio of the weight proportions of at least two alloy elements of this fraction is determined, and based on this relative ratio, this fraction is allocated to its corresponding alloy group, and then the fractions are sorted by the alloy groups to which they have been allocated.

Claims

1. A method for sorting chopped, aluminum scrap by alloy groups, the method comprising: separating the aluminum scrap into a plurality of fractions; irradiating the plurality of fractions of the aluminum scrap using at least one neutron source; using at least one detector to detect gamma radiation that an individual fraction emits due to neutron irradiation; based on the gamma radiation detected, generating an energy spectrum associated with a respective fraction; based on the energy spectrum, determining a relative ratio of weight proportions of each of at least two alloy elements of the respective fraction with respect to one another; based on the relative ratio, allocating the respective fraction to a corresponding alloy group; and then sorting each of the plurality of fractions by alloy groups to which each of the fractions have been allocated.

2. The method according to claim 1, comprising providing the aluminum scrap in chambers that are demarcated from one another and thus separating the aluminum scrap into the plurality of fractions.

3. The method according to claim 1, comprising using a conveyor system to transport the plurality of fractions to the at least one neutron source for the irradiation.

4. The method according to claim 3, wherein the conveyor system has an endless conveyor belt and the neutron source, which is provided between a working side and a return side of the conveyor belt, irradiates the plurality of fractions of the aluminum scrap through the conveyor belt and the gamma radiation that the plurality of fractions emit due to this neutron irradiation is detected by the detector provided above the working side of the conveyor belt.

5. The method according to claim 3, comprising providing the aluminum scrap in chambers that are demarcated from one another in a conveyor belt of the conveyor system.

6. The method according to claim 1, comprising conveying the neutron radiation through a lens embodied as a moderator before the neutron radiation strikes the plurality of fractions.

7. The method according to claim 1, wherein the at least one neutron source irradiates multiple fractions simultaneously.

8. The method according to claim 1, wherein a plurality of detectors for measuring the gamma radiation emitted by the fractions are provided next to one another and/or one after another.

9. The method according to claim 8, wherein the plurality of detectors, which are provided next to one another and/or one after another and are each allocated to a respective fraction to measure the gamma radiation emitted by the respective fraction, are shielded laterally from one another by a lead shield.

10. An apparatus for sorting chopped, aluminum scrap by alloy groups, the apparatus comprising: a conveyor system for transporting fractions of the aluminum scrap; a measuring device having at least one neutron source for irradiating the fractions transported by the conveyor system, at least one detector for detecting gamma radiation that the fractions emit due to neutron irradiation, and a computing unit for allocating the fractions to an alloy group as a function of their respective relative ratio of weight proportions of each of at least two of their alloy elements with respect to one another, which relative ratio is determined by the computing unit based on an energy spectrum of the gamma radiation that is detected from the respective fraction; and a sorting system, which sorts the fractions transported by the conveyor system by their alloy groups that have been allocated to each fraction by the measuring device.

11. The apparatus according to claim 10, wherein the neutron source is provided between a working side and a return side of the conveyor belt of the conveyor system.

12. The apparatus according to claim 10, wherein the conveyor belt of the conveyor system has chambers that are demarcated from one another for separating and transporting fractions.

13. The apparatus according to claim 12, wherein the conveyor belt has a plurality of chambers situated next to one another in rows and one after another in columns.

14. The apparatus according to claim 10, comprising a lens between the at least one neutron source and at least one of the fractions, wherein the lens is a moderator.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the figures, the subject of the invention is shown in greater detail by way of example based on an embodiment variant. In the drawings:

(2) FIG. 1 shows a schematic top view of an apparatus for carrying out the method according to the invention and

(3) FIG. 2 shows a sectional view through the apparatus shown in FIG. 1.

WAYS TO EMBODY THE INVENTION

(4) FIG. 1 and FIG. 2 show a method 1 for sorting chopped or shredded aluminum scrap 2 in which the aluminum scrap 2 is chopped and/or sifted and/or homogenized for example to 10 to 120 mm in a unit 3 and then divided and/or separated into fractions 4. Finally, a sorting system 5 sorts these fractions 4 by alloy groups 6.1 (e.g.: aluminum forging alloy of the alloy group 6xxx), 6.2 (aluminum forging alloy of the alloy group 7xxx), and 6.3 (aluminum casting alloy of the alloy group 3xx-AlSiCu).

(5) As shown in FIGS. 1 and 2, the aluminum scrap 2 is dispensed into chambers 14 that are demarcated from one another and is thus separated into individual fractions 4. In general, it should be noted that a fraction 4 can consist of a single piece of aluminum scrap or multiple pieces of aluminum scrap and/or also of aluminum scrap granulates or aluminum scrap powders that are composed of the aluminum scrap 2.

(6) In the simplest structural embodiment, the conveyor system 15 can constitute only one belt conveyor 115, which transports the fractions 4 from the separating unit 3 through the PGNAA measuring system 7 to the sorting system 5. As is apparent in the exemplary embodiment, the demarcated chambers 14 are composed of driving elements 15.1 and longitudinal slats 15.2 of an endless conveyor belt 15.3 of a conveyor system 15.

(7) The fractions 4 of the aluminum scrap 2 are supplied to a PGNAA measuring device 7, which is data-connected to the sorting system 5. In the PGNAA measuring device 7, the fractions 4 are irradiated with neutron radiation 8 of a neutron source 9 and the gamma radiation 10 emitted by the individual fractions 4 because of the resulting activation of their nuclei is detected by a respective detector 11. Data about the gamma radiation 10 of the individual fractions 4 are thus generated. The measurement data of the detector 11 are supplied to a computing unit 12 of the measuring device 7. It is thus possible to generate energy spectra associated with the respective fractions 4. Based on the energy spectrum of the respective fraction, a relative ratio of the weight proportions of at least two alloy elements of this fraction 4 is determined. Then based on the relative ratios of the weight proportions of alloy elements, the computing unit 12 thus individually allocates the fractions 4 to an alloy group 6.1, 6.2, or 6.3.

(8) In accordance with this allocation, the PGNAA measuring device 7 activates the sorting system 5 in such a way and is data-connected to the sorting system 5 in such a way that a fraction 4 is separated out into a respective receptacle 13 in accordance with its corresponding alloy group 6.1, 6.2, or 6.3.

(9) Such a conveyor system 15 can enable a particularly high mass throughput in the method, but can also be used for separating the aluminum scrap 2 into fractions 4.

(10) As is also clear from FIG. 2, the neutron source 9 is provided between the working side 15.4 and the return side 15.5 of the conveyor belt 15.3 and thus irradiates the fractions 4 of the aluminum scrap 2 through the working side 15.4 of the conveyor belt 15.3. The gamma radiation 10 emitted by the fractions 4 is detected by the detector 11 provided above the working side of the conveyor belt 15.3. This type of arrangement of the neutron source 9 and detector 11 achieves a compact apparatus and also makes it possible to achieve a very low interfering influence of the conveyor system 15 on the measurement, especially so that the return side 15.5 of the conveyor belt 15.3 has no influence on the irradiation of the fractions 4. The method according to the invention therefore has not only a high mass throughput, but also a high degree of selectivity.

(11) As can be particularly inferred from FIG. 2, the neutron radiation 8 from the neutron source 9 is conveyed through a lens 16 before the neutron radiation 8 strikes the fractions 4. This equalizes and homogenizes the divergent neutron radiation 8 emerging from the neutron source 9 so that it is possible to ensure that the neutron radiation 8 striking the fractions 4 is comparable in each chamber 14. This in turn makes it possible to simultaneously act on multiple fractions 4 with the neutron radiation 8 of the neutron source 9. In addition, the lens 16 is embodied as a moderator 17, as a result of which the neutrons of the neutron radiation 8 are thermalized, i.e. are decelerated to kinetic energies below approximately 100 meV. The effective collision cross-section of the neutron radiation 8 with the nuclei of the fractions 4 can thus be significantly increased, which has a positive effect on the measurement precision of the method.

(12) Particularly in order to enable a high mass throughput, multiple detectors 11 for measuring the gamma radiation 10 emitted by the fractions 4 are provided next to one another in the PGNAA measuring system. As can be inferred from FIG. 1, in particular 16 detectors 11 are arranged in four rows 19 and four columns 20, specifically in accordance with the chambers 14 of the conveyor belt 15.3 that are arranged in this way. It is thus possible to achieve a high degree of parallelism for a high mass throughput.

(13) As is clear from FIGS. 1 and 2, the detectors 11 are provided with respective shields 18. Because these detectors are shielded laterally from one another, it is advantageously possible to ensure that only the gamma radiation 10 emitted by the fraction 4 associated with the detector 11 actually strikes the respective detector 11. Otherwise, the emitted gamma radiation 10 of an external fraction 4 could interfere with the gamma radiation 10 to be measured and could thus distort the energy spectrum. A lead shield 18 has proven to be useful for producing a reliable shield.