JPH0867925A - Method for recovering automotive scrap - Google Patents

Abstract

PURPOSE: To efficiently regenerate the crushed pieces of automotive scrap as Al and Al alloys having high cleanliness by subjecting these crushed pieces to magnetic sepn., then collecting the specific plus sieves and dissolving the same. CONSTITUTION: The main components of crushed pieces of the automotive scrap are iron and steel parts occupying about 75wt.%. These iron and steel parts are recovered by magnetic sepn. after crushing and shredder treatments. The remaining parts are nonmetallic parts, org. parts and nonferrous metallic parts. The greater part among the nonferrous metallic parts are Al alloy parts. The remaining parts are classified in a sieving stage by a trommel process, etc. The plus sieves of one side 20mm are collected and are melted. The plus sieves of one side 35mm are collected and melted. As a result, the impurity components exclusive of the Al are removed as far as possible.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for recovering automobile scraps, and particularly to efficiently recover Al or Al alloys (hereinafter represented by Al alloys) contained in automobile scraps in a considerable amount as non-ferrous metals as high purity products. It is about how you can do it.

[0002]

2. Description of the Related Art A large amount of electric power is consumed for refining and manufacturing Al from ore containing Al, whereas remelting of Al or Al alloy scrap does not require much energy, and the scrap is remelted. By doing so, it can be recovered as a relatively high-purity product, which is, so to speak, excellent in recyclability. Therefore, from the viewpoint of resource saving, Al alloy scrap such as Al can material and Al sash can be recovered and reused. It is widely used.

By the way, Al alloy scrap having a relatively low content of impure elements such as Al can material and Al sash can be reused as a relatively high purity material by recovering and remelting it. On the other hand, most of the automobile scraps whose emissions as waste materials have increased rapidly in recent years are steel materials, but for example, a considerable amount of Al alloys are also included as radiator materials around engines and aluminum wheels, etc. From the viewpoint of reducing the weight of the vehicle body, the use ratio of the Al alloy tends to gradually increase, and the content ratio of the Al alloy in the automobile scrap has become considerably large. From such a place, Al is used as the non-magnetic non-ferrous metal material after the steel material is separated and collected by magnetic force selection or the like.
A method of separately collecting alloys is also in progress.

However, in addition to Al alloys, copper and other non-magnetic metals, various metal oxides, organic substances such as rubber, and the like are mixed in the non-ferrous metal materials recovered from automobile scrap, as wiring materials. Organic substances are burnt and disappeared by the heat during remelting, so the purity of reclaimed Al alloy melt is not adversely affected, but it is effective for other impure contaminants (nonmagnetic metals such as copper and metal oxides). No effective separation method has been established.
It is a major cause of lowering the purity of the alloy, and these impurities significantly deteriorate the quality of the regenerated Al alloy product. Therefore, after remelting, various refining techniques are used to improve the cleanliness, but the cost required for the refining is remarkably increased. Therefore, it is the largest bottleneck for practical use of Al-containing scrap recovery and reuse. Has become.

Therefore, in order to reduce the refining cost as much as possible and to industrially recover and reuse the Al alloy scrap, it is possible to adjust the amount of impurities mixed in the Al alloy scrap in the separate recovery stage of the Al alloy scrap before remelting. The biggest challenge for the time being is to reduce the refining load as much as possible.

[0006]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned circumstances, and its purpose is to recover an aluminum alloy from automobile scrap as a main non-ferrous metal after magnetic separation. To establish a technology that can reduce the impurities contained in the aluminum alloy as much as possible in the sorting step before remelting and regenerate it as an Al alloy having a sufficiently practical cleanliness by performing a very general refining treatment. To do.

[0007]

The structure of the recovery method according to the present invention, which has been able to achieve the above object, is a method for recovering Al or Al alloy in automobile scraps, and magnetically selects automobile scrap fragments. After doing, one side 20mm
The present invention has the gist of collecting the above sieve and melting it as at least a part of Al or Al alloy raw material. At this time, if a sieve with a side of 35 mm is sampled and melted, it can be recovered as an Al alloy having a higher cleanliness although the recovery rate is low.

[0008]

Operation and Examples Recovery of valuable components from automobile scrap is usually performed through the following steps. That is, the recovered automobile scrap has the engine, mission, underbody parts, etc. that can be reused by a dismantling company removed, and the batteries, tires, etc. that are inconvenient for crushing or shredding, etc. removed, and in some cases, After being soft pressed once, or crushed or shredded as it is, not all scraps are subjected to such pretreatment, but crushed with the engine and suspension parts inside. Alternatively, there are some that are subjected to shredder treatment, and among the crushed pieces, steel parts, non-ferrous metal parts, organic parts such as rubber and resin,
Non-metallic parts such as ceramics and glass are all included.

The main components in the crushed pieces are steel parts which account for about 75% by weight, and most of them are recovered by magnetic separation after crushing or shredding. About 7 remaining
-10% by weight is non-metallic parts such as glass and ceramics,
About 7-10% by weight is organic parts such as rubber and resin,
Most of the remaining non-ferrous metal parts are Al alloy parts, and these contain a small amount of copper parts mainly composed of electrical terminals and the like. Of these, the organic component burns and disappears due to the heat at the time of remelting, so even if it is mixed in the recovered Al alloy, its purity is not adversely affected.

Therefore, when an Al alloy is to be recovered from a non-ferrous metal material obtained as a residual component after the separation of iron and steel materials, the inclusion of impurities is a problem because it is an oxide non-metallic substance such as glass or ceramics. It is a non-ferrous metal other than Al mainly composed of copper and copper, and how to remove these efficiently in the separation step before remelting is extremely important for improving the cleanliness of the recovered Al alloy. Becomes However, in any case, it is impossible to separately collect only the Al alloy from the remaining non-magnetic components by magnetic separation or the like and to separately remove other components.

[0011] Therefore, the present inventors are not able to properly sort the recovered high Al alloy content by properly selecting a plurality of sieve-mesh passing components that are sorted in the sieving process using trommel or the like. I thought that, and proceeded with the study along that line. However, among the residual magnetic separation components, glass and ceramics are fragile and thus are finely crushed in the crushing process.Almost all non-ferrous metal parts other than Al alloy parts are electrical components and wiring materials and are relatively small. Since it is of a size, it is thought that it may be possible to recover it as one with a high Al alloy content rate by removing these small sizes with a sieve and selecting only relatively large crushed pieces and separating them. It was.

[0012] Then, the remaining components of the steel material that have been screened and removed by magnetic separation are passed through a sieve having a side of 12 mm (hereinafter, sieve size 12 m).
(sometimes referred to as m □), 20 mm □, and 35 mm □ screens, and the contained components were examined for the respective passed and non-passed parts. The results are as shown in FIG. 1 (however, the content of the organic component that burns away by the heat during melting is excluded), and the main component is the Al alloy component, but the Al alloy depends on the size of the sieve. The amount of mixed components other than the above is quite different, and an extremely large amount of non-ferrous metal components other than Al is mixed into the passing amount of the 12 mm square sieve, whereas the sieve 3
The content of non-ferrous metal components other than Al in the non-passage of 5 mm □ is very small. In addition, sieve mesh 12 mm □ to 35 mm □
It can be seen that those within the range of 1) contain a considerable amount of non-metallic components together with the non-ferrous metallic components other than the Al alloy.

From these results, it is considered that if the non-passage of 35 mm square is separately collected, it can be recovered and reused as an Al alloy having a high cleanliness without any problem, but the recovery rate as an Al alloy is 10-20 at most. % Is not secured, a satisfactory recovery rate cannot be obtained, and the purpose of recovering valuable metal components cannot be fulfilled sufficiently.

Further, Table 1 below shows the results of examining the composition of the molten metal after heat-dissolving the sorted material screened above and passing through a filter to remove nonmetallic components and the like, Also from this table, the content of non-ferrous metal components other than Al contained in the 12 mm square sieve mesh is very large, while the content of non-ferrous metal elements contained in the 35 mm square non-passage is small, The same tendency as shown in FIG. 1 can be seen.

[0015]

[Table 1]

However, when conducting the experiments shown in Table 1 above, the following unique tendency was confirmed. That is, in the experiment of Table 1, each sieving component was 720
After dissolving at 0 ° C, the insoluble component was removed by passing it through a plate filter having a mesh size of 100 µm under pressure.
The molten metal passage time in this filtration step varies significantly depending on the above-mentioned sieve passage component, and moreover, it tends to be predicted from the results obtained in FIG. 1 and Table 1 above (that is, the sieve opening size is 12 mm.
It was confirmed that the tendency is different from the tendency that a sudden change occurs around the square or around 35 mm square. That is, FIG. 2 shows that 3 kg of each of the above-mentioned four kinds of screened products was melted at 720 ° C. in an induction melting furnace, and 2 kg of each molten metal was applied with a pressure of ² kg / cm ² to form a mesh 100 μm.
3 shows the results of examining the respective passage times after passing through a plate-shaped filter of m.

As is clear from this figure, the molten metal passage time significantly changes depending on each sort, but in this figure, the molten metal passage time changes significantly before and after the sieve size of 20 mm □. I understand. As one of the simple methods for evaluating the cleanliness of Al alloys, there is a method of evaluating the filter passage time as described above. Those having a short passage time have high cleanliness, and those having a long passage time have low cleanliness. It is supposed to be. It is considered that the non-metallic insoluble oxides contained in the Al alloy molten metal mainly cause the filter clogging, and these gradually adhere and accumulate to impede the passage of the molten metal. The faster the speed, the higher the cleanliness.

From this point of view, as shown in FIG. 2, in each recovered product sorted by the sieve size, the molten metal passage speed is remarkably changed before and after the sieve size is 20 mm □ as the Sakai.
It can be seen that the Al alloy having a high cleanliness can be efficiently collected by separately collecting those which have not passed 0 mm □. Despite the results obtained in FIG. 1 and Table 1, FIG.
It is not clear why the peculiar tendency shown in Fig. 2 is obtained.
It can be confirmed that an Al alloy having a high degree of cleanliness can be recovered in a high yield by selecting and collecting those which do not pass 0 mm □.

The components after passing through the filter are as shown in Table 1, and the amount of the impure element in the regenerated Al alloy melt obtained is about 2.5% or less of Cu, and Zn which is mixed as a brazing filler metal component or the like. Is about 5%, and depending on the application, it can be cast and molded and reused as it is. However, it is preferable to carry out a refining treatment by a usual method after melting to further reduce the impure elements, or to mix with a recovered Al high-purity Al such as a new Al ingot, Al can or Al sash. By diluting these impure elements, it becomes possible to reuse them as a recycled Al alloy molten metal having no limitation in use.

As described above, in the present invention, the remaining components after magnetically screening the crushed material of automobile scrap are screened, and the 20 mm square non-passage is screened to obtain an Al alloy with a small amount of impurities. It has a characteristic in that it is recovered, and it is expected that the size of the sieve will be slightly changed depending on the conditions of the first crushing of automobile scrap or shredder treatment. However, there is no extreme difference in the conditions for crushing or shredder treatment for automobile scrap recovery that is currently in practical use, and even if those conditions are slightly different, non-passage is excluded by excluding the 20 mm square passage. It has been confirmed that all of them can be regenerated as Al alloys having high cleanliness by selecting and collecting the components.

[0021]

EFFECTS OF THE INVENTION The present invention is configured as described above, and among the remaining components after magnetically selecting the crushed material of automobile scrap, only the sieve having a side of 20 mm is selected and collected, so that other than Al. Impurity components can be excluded as much as possible, and it becomes possible to efficiently regenerate Al or Al alloy having high cleanliness.

[Brief description of drawings]

FIG. 1 is a graph showing the composition of contained components of each sieve mesh passing when the remaining components after magnetically sorting the crushed automobile scrap are sieved.

FIG. 2 is a graph showing, in comparison, a filter passage time of a lysate of a sieved sieve passage portion.

Front page continuation (72) Inventor Shingo Ninagawa 1-5-5 Takatsukadai, Nishi-ku, Kobe-shi, Hyogo Inside Kobe Steel Co., Ltd., Kobe Steel Co., Ltd. (72) Kenji Osumi 1-chome Takatsuka, Nishi-ku, Kobe No. 5-5 Inside Kobe Research Institute, Kobe Steel, Ltd.

Claims (2)

[Claims] 1. A method for recovering Al or an Al alloy in automobile scrap, which comprises magnetically selecting crushed scraps of automobile scraps, collecting a sieve having a side of 20 mm, and melting the sieve. Scrap recovery method. 2. The recovery method according to claim 1, wherein a sieve having a side of 35 mm is collected and dissolved.