METHOD FOR RECYCLING AT LEAST ONE MAGNET OF AN ELECTRIC MACHINE

Abstract

A method for recycling at least one magnet of an electric machine. A subassembly having the magnet is disassembled from the electric machine. In the process, the following steps are provided: carrying out a first thermal treatment of the subassembly at a first temperature, mechanical separation of the magnet from the subassembly, and carrying out a second thermal treatment of the magnet at a second temperature, which is higher than the first temperature, for debinding and/or cleaning of the magnet.

Claims

1. A method for recycling at least one magnet of an electric machine, wherein a subassembly having the magnet is disassembled from the electric machine, comprising the following steps: carrying out a first thermal treatment of the subassembly at a first temperature; mechanically separating the magnet from the subassembly; and carrying out a second thermal treatment of the magnet at a second temperature, winch is higher than the first temperature, for debinding and cleaning of the magnet.

2. The method according to claim 1, wherein the first temperature and a first time period, over which the first thermal treatment is carried out, are chosen in such away that, during the first thermal treatment, a magnet adhesive present at the magnet is decomposed at least partially.

3. The method according to claim 1, wherein, by means of the separation carried out after the first thermal treatment, a sheet metal part is separated mechanically from the magnet.

4. The method according to claim 1, wherein, after the first thermal treatment and prior to the second thermal treatment, the magnet is cooled to a temperature that is lower than the first temperature.

5. The method according to claim 2, wherein the second temperature and a second time period, over which the second thermal treatment is carried out, are chosen in such a way that, during the second thermal treatment, the magnet adhesive present on the magnet is completely decomposed.

6. The method according to claim 5, wherein the first temperature and the first time period are chosen in such a way that a corrosion coating of the magnet is retained completely, and wherein the second temperature and the second time period are chosen in such a way that the corrosion coating of the magnet is completely decomposed.

7. The method according to claim 1, wherein the first thermal treatment is conducted under the influence of oxygen, and the second thermal treatment is carried out under the exclusion of oxygen or under lesser influence of oxygen than during the first thermal treatment.

8. The method according to claim 1, wherein,-after the second thermal treatment, the magnet is treated in a material-removing manner.

9. The method according to claim 1, wherein the magnet is chemically or mechanically decomposed into a magnetic material.

10. The method according to claim 1, wherein the magnetic material is processed under addition of one of the following substances to yield a recycled magnet: fresh material and binder.

Description

BRIEF DESCRIPTION OF THE DRAWING

[0029] The invention will be discussed in detail below on the basis of the exemplary embodiments illustrated in the drawing, without any limitation of the invention thereby occurring. The sole FIGURE shows;

[0030] FIG. 1: a cross-sectional illustration through a subassembly of an electric machine.

DETAILED DESCRIPTION

[0031] The FIGURE shows a part of an electric machine 1 in cross section, namely a subassembly 2 of the electric machine 1. The subassembly 3 has at least one magnet 3 and, in the exemplary embodiment illustrated here, a plurality of magnets 3. The magnet 3 exists, for example, in the form of a permanent magnet. The magnet 3 is arranged in a sheet metal part 4 of the subassembly 2 or is held by it. The sheet metal part 4 is connected to the magnet 3 in a rotationally-resistant manner by a shaft 5. The shaft 5 serves for the rotatable bearing of the subassembly 2 around an axis of rotation 6 in the electric machine 1 or in a machine housing of the electric machine 1. The fastening of the magnet 3 to the sheet metal part 4 can be achieved by means of magnet adhesive.

[0032] For recycling of the magnet 3, the subassembly 2 is then initially disassembled ten the electric machine 1, in particular together with the shaft 5. Subsequently, it can be provided that the shaft 5 is detached mechanically from the subassembly 2 by, for example, pressing out the shaft 5 in the axial direction with respect to the axis of rotation 6.

[0033] Subsequently, the subassembly 2 is conveyed to a first thermal treatment at a first temperature and throughout a first time period. The first thermal treatment serves for the partial decomposition of the magnet adhesive present at the magnet 3. Subsequently, the magnet 3 is separated mechanically from the subassembly 2. This means, therefore, that the sheet metal part 4 is separated from the magnet 3. This can be carried out by shaking, for example. Other separation methods can also be provided, however. Afterwards, the magnet 3 is conveyed to a second thermal treatment at a second temperature and throughout a second time period. The second temperature is higher than the first temperature. Additionally or alternatively, the second time period is longer than the first time period. The second thermal treatment serves for the complete decomposition of the magnet adhesive.

[0034] After the second thermal treatment, it can be provided that the magnet 3 is treated in a material-removing manner by, for example, grinding and/or sandblasting. Subsequently, the magnet 3 is decomposed into a magnetic material, with this preferably being conducted chemically and/or mechanically. For example, the magnet 3 is initially cleaved chemically and then reduced in size mechanically. The former occurs, in particular, by means of hydrogen embrittlement, the latter by grinding. In this way, at recycled magnet can be produced from the obtained magnetic material. To this end, at least one additive can be added to the magnetic material, preferably with fresh material and/or a binder being used as the additive.

[0035] At least one of the thermal treatments is carried out preferably under the exclusion of oxygen. It can also be provided that the influence of oxygen during the first thermal treatment is greater than during the second thermal treatment. To this end, for example, the oxygen partial pressure during the second thermal treatment is lowered in comparison to the first thermal treatment.

[0036] It is possible by using the described method to recycle the at least one magnet 3 to produce a recycled magnet that has nearly the same magnetic properties as the magnet 3. This is achieved, in particular, by the two successive thermal treatments with the subsequent decomposition of the magnet 3 into the magnetic material.