Method for manufacturing recycled aluminum alloy and method for manufacturing recycled aluminum alloy material

Abstract

This invention provides a method for manufacturing recycled aluminum alloys that can achieve a high scrap utilization rate, stable yield, and low impurity concentration. [Solution] The method comprises the steps of: dissolving a secondary aggregate of multiple aluminum scraps containing aluminum alloy species with different chemical compositions to obtain a molten metal, generating a compound containing a second component included in the secondary aggregate; and removing the compound generated in the generation step to obtain a recycled aluminum alloy, wherein the secondary aggregate is extracted from a parent aggregate by sorting aluminum scraps based on chemical composition analysis, and the secondary aggregate is extracted from multiple aluminum scraps that were not extracted from the parent aggregate in such a way that the content of the first component is reduced, the first component is one or more selected from the group consisting of Cu, Zn, Si, and Ni, and the second component is one or more selected from the group consisting of Fe, Si, Mn, Ti, V, Zr, Cr, and Co.

Description

Technical Field

[0001] The present disclosure relates to a method for producing a recycled aluminum alloy and a method for producing a recycled aluminum alloy material.

Background Art

[0002] Currently, from the perspective of resource depletion, recycling of various materials has been progressing, and recycling of metals that are consumed in large quantities has also been carried out for a long time.

[0003] Aluminum is a metal material with excellent recyclability, and many aluminum products such as aluminum sheet expansion materials made of aluminum plates, die-cast products, and casting products are recycled into new products after being remelted after being discarded.

[0004] On the other hand, aluminum products after being discarded contain impurities due to adherents or derived from additive elements of aluminum alloys. These impurities are generally difficult to remove, and the recycled aluminum alloy generally has a high impurity concentration, so it is generally cascade recycled into products with loose component specifications.

[0005] In recent years, from the perspective of suppressing carbon dioxide emissions, there has been an increasing social demand for advanced recycling of aluminum. Therefore, in addition to the method of physically extracting aluminum from aluminum scrap containing other metals such as iron and copper in the past, a method of classifying by variety based on component analysis values by instrumental analysis is also being utilized (see Patent Document 1).

[0006] In addition, transition metal elements (Fe, Mn, Ni, Cu, Cr, etc.) mixed in from scrap or added to impart rigidity or heat resistance need to be removed so as to be within the component specifications. Many methods for removing impurities from molten aluminum or aluminum alloy have been reported. As a method for removing Fe, which is particularly difficult to remove, a technique has been proposed in which Mn, which becomes an impurity, is deliberately added to crystallize an Al-Si-Fe-Mn-based intermetallic compound, and then the intermetallic compound is removed by centrifugation, suction, etc. (see Patent Documents 2 and 3).

[0007] Furthermore, techniques have been proposed to separate Fe, Mn, Si, Cr, etc. from the molten metal as compounds by adding a high concentration of Mg and maintaining a low temperature (see Patent Document 4), and to remove peritectic elements such as Ti, Cr, V, Zr by compounding them by adding B (see Patent Document 5). [Prior art documents] [Patent Documents]

[0008] [Patent Document 1] Japanese Patent Publication No. 2019-52884 [Patent Document 2] Japanese Patent Application Publication No. 8-35021 [Patent Document 3] Japanese Patent Application Publication No. 7-70666 [Patent Document 4] Japanese Patent Publication No. 2019-183265 [Patent Document 5] Japanese Patent Publication No. 2004-300571 [Overview of the Initiative] [Problems that the invention aims to solve]

[0009] In the technology described in Patent Document 1, aluminum plates are sorted into 1000 series to 8000 series, as described in JIS H4000. Furthermore, if aluminum alloy castings described in JIS H5202 and aluminum alloy die castings described in JIS H5302 are added to the technology described in Patent Document 1, the alloys can be sorted into even more numerous alloy types. Therefore, when manufacturing recycled aluminum alloys using the technology described in Patent Document 1, a large amount of scrap with the desired chemical composition is required. However, in reality, scrap with the desired chemical composition is not always abundant, which may result in not being able to achieve the target production volume, or incurring increased costs and a decrease in scrap utilization rates due to the use of a large amount of new metal to increase production volume. In addition, because sorting into numerous alloy types is necessary, there is also the problem of the sorting equipment becoming large and complex when used.

[0010] The technologies described in Patent Documents 2 to 5 can remove specific impurity elements regardless of the alloy type of the scrap, and component analysis can also be performed, thus enabling the production of easy-to-produce and easy-to-use recycled aluminum alloys. However, if aluminum scrap with an unknown composition is used, elements that are difficult to remove in the molten state, such as Cu and Zn, may be mixed in, potentially rendering the alloy unusable for the intended purpose. Furthermore, when using these recycled aluminum alloys, it becomes necessary to use a large amount of new metal to reduce the impurity concentration, leading to increased costs and a decrease in the scrap utilization rate.

[0011] This disclosure is made in light of these circumstances and aims to provide a method for manufacturing recycled aluminum alloys that can achieve a high scrap utilization rate, stable yield, and low impurity concentration. [Means for solving the problem]

[0012] A method for producing a recycled aluminum alloy according to one aspect of the present disclosure comprises the steps of: generating a compound containing a second component in a molten metal obtained by melting a secondary aggregate of a plurality of aluminum scraps containing aluminum alloy species having different chemical components; and removing the compound generated in the generation step to obtain a recycled aluminum alloy, wherein the secondary aggregate is extracted from a parent aggregate by sorting aluminum scraps based on chemical component analysis, the secondary aggregate is extracted from a plurality of aluminum scraps that were not extracted from the parent aggregate in such a way that the content of the first component is reduced, the first component is one or more selected from the group consisting of Cu, Zn, Si, and Ni, and the second component is one or more selected from the group consisting of Fe, Si, Mn, Ti, V, Zr, Cr, and Co. [Effects of the Invention]

[0013] A method for producing recycled aluminum alloy according to one aspect of this disclosure enables the achievement of a high scrap utilization rate, stable yield, and low impurity concentration. [Brief explanation of the drawing]

[0014] [Figure 1] Figure 1 is a flowchart illustrating a method for manufacturing a recycled aluminum alloy according to one embodiment of the present disclosure. [Figure 2] Figure 2 is a flowchart showing a method for manufacturing recycled aluminum alloy according to a different embodiment than that shown in Figure 1. [Modes for carrying out the invention]

[0015] [Description of Embodiments in this Disclosure] First, the embodiments of this disclosure will be listed and described.

[0016] (1) A method for producing a recycled aluminum alloy according to one aspect of the present disclosure comprises the steps of: generating a compound containing a second component in a molten metal obtained by melting a secondary aggregate of a plurality of aluminum scraps containing aluminum alloy species having different chemical components; and removing the compound generated in the generation step to obtain a recycled aluminum alloy, wherein the secondary aggregate is extracted from a parent aggregate by sorting aluminum scraps based on chemical component analysis, the secondary aggregate is extracted from a plurality of aluminum scraps that were not extracted from the parent aggregate in such a way that the content of the first component is reduced, the first component is one or more selected from the group consisting of Cu, Zn, Si, and Ni, and the second component is one or more selected from the group consisting of Fe, Si, Mn, Ti, V, Zr, Cr, and Co.

[0017] The method for producing the recycled aluminum alloy involves dissolving a secondary aggregate extracted from the parent aggregate based on the content of the first component determined by chemical analysis, generating a compound containing the second component in the resulting molten metal, and then removing this compound to produce the recycled aluminum alloy. In other words, the method for producing the recycled aluminum alloy involves dry refining a secondary aggregate in which the first component, which is difficult to remove by dry refining, has been reduced by chemical analysis, thereby enabling the production of a recycled aluminum alloy with controlled content of both the first and second components. More specifically, when dry refining is performed with multiple varieties mixed together, there is a problem that the resulting recycled aluminum alloy cannot be used for the desired application due to elements that are difficult to remove. On the other hand, while a sorting machine equipped with instrumental analysis can extract aluminum scrap that meets predetermined component conditions, there is a problem that the amount of aluminum scrap with the desired components recovered is small, resulting in a low yield. Furthermore, when sorting based on multiple elements, the sorting process must be repeated, which increases costs. In contrast, by using a secondary aggregate from which aluminum scrap containing a large amount of the first component, which is difficult to remove by dry refining, has been excluded in the above-mentioned production process, a high-purity recycled aluminum alloy can be obtained even from scrap with an unknown composition and containing a wide variety of impurities.

[0018] (2) In the above (1), a step of extracting the secondary set to be subjected to the step of generating by sorting aluminum scraps from the above parent set of a plurality of aluminum scraps including aluminum alloy types made of different chemical components is further provided. In the step of extracting the secondary set, chemical component analysis is performed on the first component contained in the plurality of aluminum scraps in the parent set, and the secondary set may be extracted so that the content of the first component is reduced with respect to the plurality of aluminum scraps not extracted from the parent set. Thus, the method for producing the recycled aluminum alloy may be configured as a series of production methods including the step of extracting the secondary set and the step of generating.

[0019] (3) In the above (1) or (2), the plurality of aluminum scraps included in the secondary set include two or more types of aluminum alloy types selected from the group consisting of JIS A1000 series, A3000 series, A5000 series, and A6000 series, and the plurality of aluminum scraps not extracted from the parent set may include one or more types of aluminum alloys of JIS A2000 series, A4000 series, and A7000 series. According to this aspect, it is possible to easily reduce the content of the first component in the obtained recycled aluminum alloy and to easily obtain a recycled aluminum alloy having a desired chemical component.

[0020] (4) In the above (1) or (2), the plurality of aluminum scraps included in the secondary set includes one or more aluminum alloy types selected from the group consisting of JIS AC7A, ISO Al-Mg3, Al-Mg6, and Al-Mg10, and the plurality of aluminum scraps not extracted from the parent set includes one or more aluminum alloy types selected from the group consisting of JIS AC1B, AC2A, AC2B, AC3A, AC4A, AC4B, AC4C, AC4CH, AC4D, AC5A, AC8A, AC8B, AC8C, AC9A, AC9B, ISO Al-Cu4Ti, Al-Si5, Al-Si5Mg, Al-Si5Cu3, Al-Si6Cu4, Al-Si10Mg, Al-Si12, Al-Si12Cu, Al-Mg5Si1, and Al-Zn5Mg. According to this aspect, it is possible to easily reduce the content of the first component in the obtained recycled aluminum alloy and easily obtain a recycled aluminum alloy having a desired chemical composition.

[0021] (5) In the above (1) or (2), the plurality of aluminum scraps included in the secondary set includes one or more aluminum alloy types selected from the group consisting of JIS ADC5, ADC6, and ISO Al-Mg9, and the plurality of aluminum scraps not extracted from the parent set includes one or more aluminum alloy types selected from the group consisting of JIS ADC1, ADC3, ADC10, ADC10Z, ADC12, ADC12Z, ADC14, ISO Al-Si9, Al-Si12(Fe), Al-Si10Mg(Fe), Al-Si8Cu3, Al-Si9Cu3(Fe), Al-Si9Cu3(Fe)(Zn), Al-Si11Cu2(Fe), Al-Si11Cu3(Fe), Al-Si12Cu1(Fe), and Al-Si17Cu4Mg. According to this aspect, it is possible to easily reduce the content of the first component in the obtained recycled aluminum alloy and easily obtain a recycled aluminum alloy having a desired chemical composition.

[0022] (6) In any of (1) to (5) above, the aluminum scraps that were not extracted from the parent aggregate may contain at least one of the following in terms of chemical composition: Cu: 0.15 mass% or more, Zn: 0.25 mass% or more, Si: 0.60 mass% or more, and Ni: 0.10 mass% or more. According to this embodiment, the content of the first component in the resulting recycled aluminum alloy can be easily reduced, and a recycled aluminum alloy with the desired chemical composition can be easily obtained.

[0023] (7) In any of (1) to (6) above, the plurality of aluminum scraps included in the secondary assembly may contain at least one of the following in terms of chemical composition: Cu: 1.0 mass% or less, Zn: 1.0 mass% or less, Si: 1.5 mass% or less, and Ni: 0.5 mass% or less. According to this embodiment, the content of the first component in the resulting recycled aluminum alloy can be easily reduced, and a recycled aluminum alloy with the desired chemical composition can be easily obtained.

[0024] (8) In any of (1) to (7) above, the chemical composition analysis is preferably performed on solid aluminum scrap. According to this embodiment, the content of the first component can be easily and reliably measured, and a secondary aggregate can be easily formed from the aluminum scrap after analysis.

[0025] (9) In any of (1) to (8) above, the chemical component analysis may be based on laser-induced breakdown spectroscopy. According to this embodiment, the content of the first component can be measured more easily and quickly.

[0026] (10) In any of (1) to (9) above, it is preferable to produce an intermetallic compound containing the second component as the compound by adding Mg to the molten metal in the production step. According to this embodiment, recycled aluminum alloy in which the content of both the first component and the second component is reduced can be easily and reliably obtained.

[0027] (11) In any of (1) to (9) above, the second component may contain one or more selected from the group consisting of Ti, V, Zr, and Cr, and in the step of production, the addition of B to the molten metal may produce a boride of the second component as the compound. According to this embodiment, recycled aluminum alloys in which the content of the first component and one or more selected from the group consisting of Ti, V, Zr, and Cr is reduced can be easily and reliably obtained.

[0028] (12) In (10) above, the second component may contain one or more selected from the group consisting of Ti, V, Zr, and Cr, and in the above production step, the addition of B to the molten metal may produce a boride of the second component as the compound. In the above production step, by adding both Mg and B to the molten metal, a recycled aluminum alloy in which the content of both the first component and the second component is reduced can be obtained more easily and reliably.

[0029] (13) In any of the above (1) to (12), it is preferable to further include a step of adjusting the composition of the molten metal after the above compound has been removed. According to this embodiment, recycled aluminum alloys can be easily manufactured according to the application.

[0030] (14) In any of the above (1) to (13), it is preferable to further include one or more melting and casting steps in which the recycled aluminum alloy obtained in the step of obtaining the recycled aluminum alloy is melted and cast. According to this embodiment, the utilization of the obtained recycled aluminum alloy can be made easier.

[0031] (15) In the above (14), it is preferable to adjust the composition of the molten metal obtained by melting the recycled aluminum alloy in the melting and casting process. According to this embodiment, recycled aluminum alloys can be easily manufactured according to the application. Furthermore, slabs that will serve as the basis for wrought materials can be manufactured.

[0032] (16) In any of the above (2) or (3) to (15) that reference the above (2), it is preferable to further include a step of removing foreign matter other than aluminum that is mixed in the parent set before the step of extracting the secondary set. According to this embodiment, even if the parent set contains nonmetallic foreign matter such as rubber or resin, or metals other than aluminum such as iron, copper, lead, or zinc, the desired recycled aluminum alloy can be easily produced.

[0033] (17) In (2) above, or in any of (3) to (16) above which reference (2) above, it is preferable to further include a step of removing at least one of the oil, paint, or coating adhering to the surface of the plurality of aluminum scraps in the parent set before the step of extracting the secondary set. According to this embodiment, the extraction accuracy in the step of extracting the secondary set is improved. As a result, the desired recycled aluminum alloy can be easily manufactured. In addition, according to this embodiment, the amount of soot generated in the generation step can be reduced.

[0034] (18) In any of (1) to (17) above, the chemical composition of at least some of the aluminum scrap in the aggregate may be unknown. The method for producing recycled aluminum is particularly effective when the chemical composition of at least some of the aluminum scrap in the aggregate is unknown.

[0035] (19) In any of the above (1) to (18), it is preferable to further include a step of sampling the molten metal after the above compound has been removed and performing a component analysis. According to this embodiment, the quality of the resulting recycled aluminum alloy can be controlled more reliably.

[0036] (20) In any of the above (1) to (19), the process may further include a step of extracting one or more aluminum scraps made of JIS A1000 series aluminum alloy from the parent aggregate, and a step of mixing the one or more aluminum scraps extracted in the aluminum scrap extraction step with the molten metal after the compound has been removed. This embodiment can improve the efficiency of manufacturing recycled aluminum alloys.

[0037] (21) A method for manufacturing recycled aluminum alloy material according to another aspect of the present disclosure comprises a step of plastically working a recycled aluminum alloy obtained by any of the methods for manufacturing recycled aluminum alloy described in (1) to (20) above.

[0038] According to the method for producing recycled aluminum alloy materials, recycled aluminum alloy materials having a desired chemical composition can be produced.

[0039] The embodiments of this disclosure will be described in detail below with reference to the drawings. It should be noted that, regarding the numerical values ​​described herein, only one of the upper and lower limits may be adopted, or the upper and lower limits may be combined in any way. In this specification, all possible numerical ranges that can be combined are described as preferred ranges. In this disclosure, the designations "first" and "second" are for distinguishing the components to which they are attached and do not limit the number, order, priority, etc.

[0040] [First Embodiment] <Method for manufacturing recycled aluminum alloy> A method for producing a recycled aluminum alloy according to one aspect of the present disclosure, as shown in Figure 1, comprises: step S2 of generating a compound containing a second component in a molten metal obtained by melting a secondary aggregate of a plurality of aluminum scraps containing aluminum alloy species with different chemical compositions; and step S3 of removing the compound generated in step S2 to obtain a recycled aluminum alloy. The secondary aggregate is extracted from a parent aggregate by sorting aluminum scraps based on chemical composition analysis. The secondary aggregate is extracted from a plurality of aluminum scraps that were not extracted from the parent aggregate in such a way that the content of the first component is reduced. The first component is one or more selected from the group consisting of Cu, Zn, Si, and Ni. The second component is one or more selected from the group consisting of Fe, Si, Mn, Ti, V, Zr, Cr, and Co. Cu, Zn, Si, Ni, Fe, Mn, Ti, V, Zr, Cr, and Co each represent an element.

[0041] The method for manufacturing the recycled aluminum alloy (hereinafter also simply referred to as "the manufacturing method") involves dissolving a secondary aggregate of aluminum scrap extracted from a parent aggregate based on the content of the first component determined by chemical composition analysis, generating a compound containing the second component in the resulting molten metal, and then removing this compound to produce the recycled aluminum alloy. In other words, the manufacturing method allows for the production of a recycled aluminum alloy in which the content of both the first and second components is controlled by performing a dry refining treatment in step S2, which generates the first component, which is difficult to remove by dry refining, in a secondary aggregate of aluminum scrap that has been reduced by sorting accompanied by chemical composition analysis. More specifically, if dry refining is performed with an unknown alloy species mixed in, there is a problem that the resulting recycled aluminum alloy cannot be used for the desired application due to elements that are difficult to remove. On the other hand, while a sorting machine equipped with instrumental analysis can extract aluminum scrap of the desired alloy species, there is a problem that the amount of aluminum scrap with the desired components recovered is small, resulting in a low yield. In contrast, by using a secondary aggregate in the generation process S2 from which aluminum scrap containing a large amount of the primary component, which is difficult to remove by dry refining, a sufficient amount of high-purity recycled aluminum alloy can be obtained even from scrap with an unknown composition and containing a wide variety of impurities.

[0042] To further explain the features of this manufacturing method compared to conventional technology, when using the technology described in Patent Document 1, it is thought that recycled material with the desired chemical composition can be obtained by finely sorting aluminum scrap according to alloy type. However, if sufficient aluminum scrap with the desired chemical composition cannot be obtained, a large amount of new metal will have to be used to obtain the target production volume, reducing the utilization rate of aluminum scrap. In addition, since it is necessary to sort into many alloy types, the equipment becomes large. On the other hand, according to the technologies described in Patent Documents 2 to 5, recycled material can be produced regardless of the alloy type of aluminum scrap, which is advantageous in terms of production volume and is also more cost-effective than the segregation method. However, in the technologies described in Patent Documents 2 to 5, there are components that are difficult to remove, such as Cu, Zn, Si, and Ni. Therefore, if these components are contained in the aluminum scrap, the target chemical composition may not be obtained, or a large amount of new metal may have to be used to dilute these components, which may reduce the utilization rate of aluminum scrap. In contrast, this manufacturing method can exclude specific alloy types through sorting (physical sorting) and then generate compounds of multiple types of impurities through dry refining, which can be removed simultaneously. Therefore, this manufacturing method can achieve both quantity and purity, and can improve the utilization rate of aluminum scrap at a low cost. In this manufacturing method, both the first and second components contain Si. This is because if the Si concentration is low, it can be sufficiently removed in the generation process S2, but if the Si concentration is high, using only the generation process S2 would result in disadvantages such as excessive Mg consumption.

[0043] The manufacturing method may further include a step S1 for extracting a secondary set to be used in step S2, which is produced by sorting aluminum scraps, from a parent set of multiple aluminum scraps containing aluminum alloy species with different chemical compositions, as shown in Figure 2. In step S1 for extracting the secondary set, a chemical composition analysis is performed on the first component contained in the multiple aluminum scraps of the parent set, and a secondary set is extracted from the multiple aluminum scraps that were not extracted from the parent set in such a way that the content of the first component is reduced.

[0044] The manufacturing method may comprise a series of steps, as shown in Figure 2, including a step S1 for extracting a quadratic set, a step S2 for generating the material, and a step S3 for obtaining a recycled aluminum alloy. Alternatively, the manufacturing method may omit the step S1 for extracting a quadratic set, as shown in Figure 1. If the manufacturing method does not include the step S1 for extracting a quadratic set, the manufacturing method may perform the generating step S2 and the step S3 for obtaining the recycled aluminum alloy using a quadratic set obtained at another facility or the like.

[0045] The following describes a case where the manufacturing method comprises a series of steps: step S1 for extracting a quadratic set, step S2 for generating the alloy, and step S3 for obtaining a recycled aluminum alloy. However, as mentioned above, step S1 for extracting the quadratic set may be performed at another facility.

[0046] (The process of extracting a quadratic set) Step S1 for extracting the secondary set is a sorting step for aluminum scrap. In step S1 for extracting the secondary set, multiple aluminum scraps containing a large amount of the first component, which is difficult to remove by dry refining, are removed from the parent set and extracted as a secondary set. In this disclosure, "parent set" means a collection of multiple aluminum scraps arbitrarily assembled, and its chemical composition may be irregular. In step S1 for extracting the secondary set, a chemical composition analysis is performed on the parent set. This chemical composition analysis is performed, for example, on one or more elements (first component) from among the alloying elements contained in each aluminum scrap in the parent set, particularly Cu, Zn, Si, and Ni. In a preferred embodiment, the chemical composition analysis measures the content of the first component contained in each aluminum scrap, and the aluminum scraps are sorted based on the content of the first component. In this sorting, some of the aluminum scrap from the parent set is not extracted, while other parts of the aluminum scrap from the parent set are extracted and form a secondary set. For example, aluminum scrap in which the content of the first component is below a threshold is extracted, while aluminum scrap in which the content of the first component is above a threshold is excluded. In this disclosure, "exclude" means not to extract from the population set and not to include in the secondary set. As a result of such selection, each piece of aluminum scrap included in the secondary set will have a lower content of at least one of the first components compared to each piece of aluminum scrap that was not extracted from the population set. The average content of the first component in the secondary set is reduced compared to the average content of the first component in the population set. In step S1 of extracting the secondary set, it is preferable to set a threshold for each of the first component content, measure the content of all these elements, and extract multiple pieces of aluminum scrap in which all content is below the threshold as the secondary set. The first component may be one or more of Cu, Zn, and Si, or one or two of Cu and Zn, or Cu, Si, Zn, or Ni. Alternatively, chemical analysis can be used to determine whether or not each piece of aluminum scrap contains the first component, and the aluminum scrap may be sorted based on the presence or absence of the first component.The step S1 of extracting the quadratic set may be performed by a person, but is preferably performed in an automated manner by a sorting device equipped with chemical component analysis equipment.

[0047] In step S1, where a secondary set is extracted, the multiple aluminum scraps included in the secondary set may include two or more aluminum alloy types selected from the group consisting of JIS A1000, A3000, A5000, and A6000 series. In addition, the multiple aluminum scraps not extracted from the parent set may include one or more aluminum alloy types from JIS A2000, A4000, and A7000 series. By excluding JIS A2000, A4000, and A7000 series aluminum scraps containing high concentrations of Cu, Si, and Zn in step S1, and selecting aluminum scraps with chemical compositions of other series, the content of the first component in the resulting recycled aluminum alloy can be easily reduced, and a recycled aluminum alloy with the desired chemical composition can be easily obtained. Furthermore, according to this embodiment, it is not necessary to select a large number of alloy types in step S1, where the secondary set is extracted. Therefore, the equipment can be miniaturized.

[0048] In step S1, which extracts a secondary set, the multiple aluminum scraps included in the secondary set may include one or more aluminum alloy species selected from the group consisting of JIS AC7A, ISO Al-Mg3, Al-Mg6, and Al-Mg10. In addition, the multiple aluminum scraps that were not extracted from the parent set may include one or more aluminum alloy species selected from the group consisting of JIS AC1B, AC2A, AC2B, AC3A, AC4A, AC4B, AC4C, AC4CH, AC4D, AC5A, AC8A, AC8B, AC8C, AC9A, AC9B, ISO Al-Cu4Ti, Al-Si5, Al-Si5Mg, Al-Si5Cu3, Al-Si6Cu4, Al-Si10Mg, Al-Si12, Al-Si12Cu, Al-Mg5Si1, and Al-Zn5Mg. According to this embodiment, aluminum alloy castings with high concentrations of Si, Cu, and Zn can be excluded, thereby easily reducing the content of the first component in the resulting recycled aluminum alloy and easily obtaining a recycled aluminum alloy with the desired chemical composition. Furthermore, according to this embodiment, it is not necessary to sort into a large number of alloy types in step S1, which is the extraction of the secondary set. Therefore, the apparatus can be miniaturized.

[0049] In step S1, which extracts a secondary set, the multiple aluminum scraps included in the secondary set may include one or more aluminum alloy species selected from the group consisting of JIS ADC5, ADC6, and ISO Al-Mg9. In addition, the multiple aluminum scraps that were not extracted from the parent set may include one or more aluminum alloy species selected from the group consisting of JIS ADC1, ADC3, ADC10, ADC10Z, ADC12, ADC12Z, ADC14, ISO Al-Si9, Al-Si12(Fe), Al-Si10Mg(Fe), Al-Si8Cu3, Al-Si9Cu3(Fe), Al-Si9Cu3(Fe)(Zn), Al-Si11Cu2(Fe), Al-Si11Cu3(Fe), Al-Si12Cu1(Fe), and Al-Si17Cu4Mg. According to this embodiment, aluminum alloy die castings with high Si concentrations can be excluded, thereby easily reducing the content of the first component in the resulting recycled aluminum alloy and easily obtaining recycled aluminum alloy with the desired chemical composition. Furthermore, according to this embodiment, it is not necessary to sort into a large number of alloy types in step S1, which is the extraction of the secondary set. Therefore, the apparatus can be miniaturized.

[0050] In step S1, which extracts a secondary set, the multiple aluminum scraps included in the secondary set may satisfy at least one of the following chemical compositions: Cu: 1.0 mass% or less if the first component contains Cu, Zn: 1.0 mass% or less if the first component contains Zn, Si: 1.5 mass% or less if the first component contains Si, and Ni: 0.5 mass% or less if the first component contains Ni. Furthermore, the above chemical composition may satisfy two or more of the following: Cu: 1.0 mass% or less, Zn: 1.0 mass% or less, Si: 1.5 mass% or less, and Ni: 0.5 mass% or less, or all of them. Note that in this disclosure, the content range for which only the upper limit is specified includes 0. According to this embodiment, the content of the first component in the resulting recycled aluminum alloy can be easily reduced, and a recycled aluminum alloy with a desired chemical composition can be easily obtained. The Cu content being 1.0 mass% or less allows exclusion from the JIS A2000 series. Furthermore, the upper limit for Cu content may be 0.40 mass%, considering the exclusion of some elements from the JIS A6000, A5000, and A3000 series in addition to the JIS A2000 series, and may be 0.15 mass%, further reducing the Cu content. A Zn content of 1.0 mass% or less allows for the exclusion of some elements from the JIS A7000 and A3000 series. The upper limit for Zn content may be 0.50 mass%, or 0.25 mass%, from the perspective of further reducing the Zn content. A Si content of 1.5 mass% or less reduces the load in the production process S2. The upper limit for Si content may be 1.0 mass%, or 0.60 mass%, from the perspective of reducing the Zn content. Ni is an element not used outside of the JIS A2000 series and is difficult to remove by dry refining, so a lower content is sometimes preferable. The upper limit for the Ni content may be 0.20% by mass or 0.10% by mass. By lowering the upper limit for the content of the first component in the extracted aluminum scrap, recycled aluminum alloys with a low concentration of the first component can be easily obtained.

[0051] In step S1, where a secondary set is extracted, any aluminum scraps not extracted from the parent set may satisfy at least one of the following chemical compositions: Cu: 0.15 mass% or more if the first component contains Cu, Zn: 0.25 mass% or more if the first component contains Zn, Si: 0.60 mass% or more if the first component contains Si, and Ni: 0.10 mass% or more if the first component contains Ni. Furthermore, the above chemical composition may satisfy two or more of the following: Cu: 0.15 mass% or more, Zn: 0.25 mass% or more, Si: 0.60 mass% or more, and Ni: 0.10 mass% or more, or all of them. According to this embodiment, the content of the first component in the resulting recycled aluminum alloy can be easily reduced, and a recycled aluminum alloy with a desired chemical composition can be easily obtained. The lower limit of the Cu content may be 0.40 mass% or 1.0 mass%. The lower limit of the Zn content may be 0.50 mass% or 1.0 mass%. The lower limit of the Si content may be 1.0 mass% or 1.5 mass%. The lower limit of the Ni content may be 0.20 mass% or 0.50 mass%. By raising the lower limit of the content of the first component in the aluminum scrap that is excluded by sorting, the amount of aluminum scrap that is excluded decreases and the amount of aluminum scrap that is extracted increases, so that a large amount of recycled aluminum alloy can be obtained.

[0052] The above chemical composition analysis is preferably performed on solid aluminum scrap. According to this embodiment, the content of the first component can be easily and reliably measured, and a secondary aggregate can be easily formed from the aluminum scrap after analysis.

[0053] Examples of methods for the above-mentioned chemical component analysis include X-ray-based methods such as LIBS (laser-induced breakdown spectroscopy), PGNAA (prompt gamma-ray neutron activation analysis), XRF (X-ray fluorescence analysis), XRT (transmission X-ray analysis), and SEM-EDX (energy-dispersive X-ray spectroscopy). Among these, the above-mentioned chemical component analysis is preferably based on LIBS. According to this embodiment, the content of the first component can be measured more easily and quickly, and the step S1 of extracting the secondary set can be performed efficiently. However, the chemical component analysis is not limited to identifying the specific value of the content of the first component. The chemical component analysis may, for example, involve applying a reagent to the surface of aluminum scrap and detecting a change in the color tone of the surface.

[0054] The chemical composition of at least some of the aluminum scrap in the above-mentioned population may be unknown. If the chemical composition of the aluminum scrap is known in advance, it may be sufficient to perform only one of the steps S1 for extracting the secondary population and the step S2 for generating the secondary population. This manufacturing method is particularly effective when the chemical composition of at least some of the aluminum scrap in the above-mentioned population is unknown.

[0055] In step S1, which extracts the secondary set, the material may be separated into multiple types in a single inspection. At this time, aluminum scrap containing a specific type of aluminum alloy may be separated and recovered. The aluminum scrap to be separated and recovered is not particularly limited, but may be, for example, from the JIS A1000 series. That is, the manufacturing method may include a step of extracting one or more aluminum scraps consisting of JIS A1000 series aluminum alloys from the parent set. When extracting one or more aluminum scraps consisting of JIS A1000 series aluminum alloys, for example, materials with Si: 0.3 mass% or less, Fe: 0.5 mass% or less, Cu: 0.05 mass% or less, Mn: 0.05 mass% or less, Mg: 0.05 mass% or less, Zn: 0.1 mass% or less, V: 0.05 mass% or less, Ti: 0.05 mass% or less, other elements: 0.03 mass% or less, and the remainder being Al may be considered as JIS A1000 series and extracted.

[0056] The separated and collected aluminum scrap can also be recycled without going through the generation process S2. In this case, the aluminum scrap may be used outside of the manufacturing method. On the other hand, the manufacturing method may use one or more aluminum scraps (for example, those of the JIS A1000 series) separated and collected in the aluminum scrap extraction process in the process S3 for obtaining the recycled aluminum alloy described later. For example, the manufacturing method may include a step of mixing one or more aluminum scraps extracted in the aluminum scrap extraction process with molten metal after the compound (the compound produced in the generation process S) has been removed. The molten metal into which the aluminum scrap is mixed may be molten metal immediately after the compound has been removed, or it may be molten metal obtained by remelting the solidified body of this molten metal. By including the aluminum scrap extraction process and the mixing process, the manufacturing efficiency of the recycled aluminum alloy can be improved.

[0057] (The process of generating) In step S2, the compound containing the second component included in the secondary aggregate is produced by dry refining. In step S2, the compound is produced in the molten metal obtained by dissolving the secondary aggregate, and the compound is separated from the molten metal.

[0058] In step S2, the compounding process, an intermetallic compound containing the second component may be formed by adding Mg (magnesium) to the molten metal obtained by dissolving the secondary aggregate. By adding an excess of Mg to the molten metal and lowering its temperature, Si can be separated as Mg2Si, and the other second components (Fe, Mn, Ti, V, Zr, Cr, Co) can be separated as intermetallic compounds with Al. Since elements that are difficult to separate by dry refining are removed in advance in step S1, the extraction of the secondary aggregate, this embodiment makes it possible to easily and reliably obtain a recycled aluminum alloy with reduced content of both the first and second components. The casting after the above compounds have been removed can be used, for example, to produce one or more recycled aluminum alloys of the JIS A5000, A6000, and A7000 series that contain Mg. It is preferable to add Be, for example, 5 to 50 ppm, before or after the addition of Mg. The addition of Be suppresses the oxidation of Mg.

[0059] Furthermore, the second component may contain one or more elements selected from the group consisting of Ti, V, Zr, and Cr. In this case, in step S2 of the generation process, the boride of the second component may be generated as the compound by adding B (boron) to the molten metal obtained by dissolving the secondary aggregate. By adding an excess of B to the molten metal and controlling the temperature of the molten metal, the peritectic elements (Ti, V, Zr, Cr) form borides. As a result, these borides can be separated in the molten metal. According to this embodiment, recycled aluminum alloys in which the content of the first component and one or more elements selected from the group consisting of Ti, V, Zr, and Cr are reduced can be easily and reliably obtained.

[0060] In step S2, the process of generating the alloy, either Mg or B may be added to the molten metal obtained by dissolving the secondary aggregate. Alternatively, both Mg and B may be added to the molten metal obtained by dissolving the secondary aggregate in step S2. By adding both Mg and B to the molten metal in step S2, a recycled aluminum alloy in which the content of both the first and second components is reduced can be obtained more easily and reliably.

[0061] (Process for obtaining recycled aluminum alloy) In step S3 for obtaining recycled aluminum alloy, the compound produced in step S2 is removed to obtain recycled aluminum alloy. In step S3 for obtaining recycled aluminum alloy, for example, the compound separated in the molten metal may be removed from the molten metal. Procedures for removing the compound include, for example, attaching it to a flux, filtering it with a refractory filter, or allowing it to precipitate in the molten metal and recovering only the supernatant. Alternatively, in step S3 for obtaining recycled aluminum alloy, the molten metal from which the compound has been separated may be solidified, and the compound may be removed from this solidified body. Procedures for removing the compound include, for example, cutting the parts where the compound has aggregated.

[0062] In step S3, which is the process for obtaining recycled aluminum alloy, the molten metal obtained in step S2 may be cast using a mold of any shape. The shape of the mold may be, for example, boat-shaped. Alternatively, the mold may be simply a recovery container. Furthermore, in step S3, which is the process for obtaining recycled aluminum alloy, it is also possible to form slabs or billets by a semi-continuous casting method. The material of the mold is not particularly limited as long as the molten recycled aluminum alloy can be safely recovered, and may be iron, refractory material, graphite, or silicon carbide. If a semi-continuous casting method is used, it may also be aluminum or copper. Moreover, in step S3, which is the process for obtaining recycled aluminum alloy, it is also possible to obtain plate-shaped or coil-shaped recycled aluminum alloy without using a mold by a twin-roll casting method.

[0063] (Other processes) As described above, the manufacturing method can be carried out by a procedure including a step S1 for extracting a quadratic set, a step S2 for generating, and a step S3 for obtaining a recycled aluminum alloy, or by a procedure including a step S2 for generating and a step S3 for obtaining a recycled aluminum alloy. On the other hand, the manufacturing method may also include the following steps as optional steps.

[0064] (Melting and casting process) The manufacturing method may include one or more melting and casting steps in which the recycled aluminum alloy obtained in step S3 is melted and cast. The melting and casting steps may be performed to change the shape of the recycled aluminum alloy obtained in step S3. For example, the recycled aluminum alloy obtained in step S3 may be transformed into an ingot, slab, billet, or casting. Alternatively, the recycled aluminum alloy obtained in step S3 may be transformed into a sheet material by twin-roll casting. Alternatively, the recycled aluminum alloy obtained in step S3 may be transformed into an ingot, and this ingot may be further transformed into a slab, billet, casting, sheet material, etc. By including the melting and casting steps, the manufacturing method can facilitate the use of the obtained recycled aluminum alloy and increase its usage.

[0065] (Component adjustment process) The manufacturing method may include a step of adjusting the composition of the molten metal after the compound (the compound produced in step S2) has been removed (first component adjustment step), or a step of adjusting the composition of the molten metal obtained by melting the recycled aluminum alloy in the melting and casting step (second component adjustment step). The manufacturing method may include only one of the first component adjustment step and the second component adjustment step, or both.

[0066] In the first and second component adjustment steps described above, one or more of the following are added: for example, alloy components, new metal, recycled metal, and other aluminum scrap. Alternatively, one or more aluminum scraps that were not extracted from the parent set in step S1, which extracts the secondary set, may be added. By adding these aluminum scraps, one or more components selected from the group consisting of Cu, Zn, Si, and Ni can be prepared. By including the first component adjustment step, this manufacturing method can easily produce recycled aluminum alloys according to the application. Furthermore, by including the second component adjustment step, this manufacturing method can easily produce recycled aluminum alloys according to the application. In addition, slabs that will serve as the basis for wrought materials can be produced.

[0067] (Removal process) The manufacturing method may include a step (first removal step) to remove foreign matter other than aluminum mixed in the parent set before step S1 to extract the secondary set. Furthermore, the manufacturing method may include a step (second removal step) to remove at least one of oil, paint, or coating adhering to the surface of multiple aluminum scraps in the parent set before step S1 to extract the secondary set. The manufacturing method may include only one of the above first removal step and the above second removal step, or both.

[0068] In the first removal step described above, foreign matter such as plastic, vinyl, iron, copper, brass, zinc, stainless steel, and precious metals mixed in with the aluminum scrap is removed. Examples of methods for removing the foreign matter include air separation, magnetic separation, specific gravity separation, manual separation, and image separation. The manufacturing method may include multiple aluminum scraps containing a wide variety of waste in the base aggregate. In this case, the manufacturing method, by including the first removal step described above, can easily produce the desired recycled aluminum alloy, and can easily produce the desired recycled aluminum alloy even if the base aggregate contains non-metallic foreign matter such as rubber and resin, or metals other than aluminum such as iron, copper, lead, and zinc.

[0069] In the second removal step described above, at least one of oil, paint, or coating adhering to the surface of the aluminum scrap is removed so that the chemical component analysis can be performed with high accuracy. By including the second removal step, the extraction accuracy in step S1, in which the secondary aggregate is extracted, is improved in this manufacturing method. As a result, the desired recycled aluminum alloy can be easily produced. Furthermore, according to this embodiment, the amount of soot generated in step S2, in which the alloy is produced, can be reduced.

[0070] (component analysis process) The manufacturing method may include a step of sampling the molten metal after the compound (the compound produced in step S2) has been removed and performing a component analysis (component analysis step). The component analysis step may be performed on the molten metal obtained in the melting and casting step, for example, but it is preferable to perform it on the molten metal obtained in step S3 for obtaining the recycled aluminum alloy. By including the component analysis step, the manufacturing method can more reliably control the quality of the resulting recycled aluminum alloy. More specifically, by including the component analysis step, the manufacturing method can easily control the quality even when using aluminum scrap with unknown chemical composition, and can reduce the risk of deviations from component specifications during recycling.

[0071] [Second Embodiment] <Method for manufacturing recycled aluminum alloy materials> A method for manufacturing recycled aluminum alloy material according to one aspect of this disclosure comprises a step of plastically processing the recycled aluminum alloy obtained by the above-described method for manufacturing recycled aluminum alloy.

[0072] According to the method for producing recycled aluminum alloy materials, recycled aluminum alloy materials having a desired chemical composition can be produced.

[0073] (The process of plastic deformation) In the plastic deformation process described above, recycled aluminum alloys are subjected to plastic deformation processes such as rolling, extrusion, and forging to obtain wrought materials, forged materials, and other recycled aluminum alloy materials. The plastic deformation process described above can be performed according to the intended use of the recycled aluminum alloy material.

[0074] [Other embodiments] The above embodiments do not limit the configuration of the present invention. Therefore, the above embodiments allow for the omission, substitution, or addition of components of each part of the above embodiments based on the description herein and common technical knowledge, and all such omissions, substitutions, or additions should be interpreted as falling within the scope of the present invention.

[0075] For example, the manufacturing method may include steps other than those described in the above embodiment. Furthermore, while several selection conditions were exemplified in step S1 for extracting a secondary set in the first embodiment, the selection conditions may differ from those described in the first embodiment, as long as the secondary set is extracted such that the content of the first component in multiple aluminum scraps included in the secondary set (i.e., the average content of the first component in the secondary set) is less than the content of the first component in multiple aluminum scraps that were not extracted from the parent set (i.e., the average content of the first component in the set of aluminum scraps that were not extracted from the parent set).

Claims

1. A step of generating a compound containing a second component included in the secondary aggregate in a molten metal obtained by melting a secondary aggregate of multiple aluminum scraps containing aluminum alloy species with different chemical compositions, A step to obtain recycled aluminum alloy by removing the compound produced in the above production step, Equipped with, The above quadratic set was extracted from the population set by sorting aluminum scrap based on chemical composition analysis. The above secondary set is obtained by extracting multiple aluminum scraps that were not extracted from the above population set, such that the content of the first component is reduced. The first component described above is one or more selected from the group consisting of Cu, Zn, Si, and Ni. The second component described above is one or more selected from the group consisting of Fe, Si, Mn, Ti, V, Zr, Cr, and Co. A method for manufacturing recycled aluminum alloys.

2. The process further comprises extracting the secondary set from the parent set of multiple aluminum scraps containing aluminum alloy species with different chemical compositions, which is to be used in the process of producing the above by sorting aluminum scraps. A method for producing recycled aluminum alloy according to claim 1, wherein in the step of extracting the above secondary set, a chemical composition analysis is performed on the first component contained in the plurality of aluminum scraps of the above parent set, and the secondary set is extracted from the plurality of aluminum scraps that were not extracted from the above parent set in such a way that the content of the first component is reduced.

3. The multiple aluminum scraps included in the above secondary set include two or more types of aluminum alloys selected from the group consisting of JIS A1000 series, A3000 series, A5000 series, and A6000 series. A method for producing recycled aluminum alloy according to claim 1, wherein multiple aluminum scraps not extracted from the above-mentioned population include one or more aluminum alloys of the JIS A2000, A4000, and A7000 series.

4. The multiple aluminum scraps included in the above secondary set contain one or more aluminum alloy species selected from the group consisting of JIS AC7A, ISO Al-Mg3, Al-Mg6, and Al-Mg10. A method for producing recycled aluminum alloy according to claim 1, wherein multiple aluminum scraps not extracted from the above-mentioned population include one or more aluminum alloy species selected from the group consisting of JIS AC1B, AC2A, AC2B, AC3A, AC4A, AC4B, AC4C, AC4CH, AC4D, AC5A, AC8A, AC8B, AC8C, AC9A, AC9B, ISO Al-Cu4Ti, Al-Si5, Al-Si5Mg, Al-Si5Cu3, Al-Si6Cu4, Al-Si10Mg, Al-Si12, Al-Si12Cu, Al-Mg5Si1, and Al-Zn5Mg.

5. The multiple aluminum scraps included in the above secondary set contain one or more aluminum alloy types selected from the group consisting of JIS ADC5, ADC6, and ISO Al-Mg9. A method for producing recycled aluminum alloy according to claim 1, wherein multiple aluminum scraps not extracted from the above-mentioned population include one or more aluminum alloy species selected from the group consisting of JIS ADC1, ADC3, ADC10, ADC10Z, ADC12, ADC12Z, ADC14, ISO Al-Si9, Al-Si12(Fe), Al-Si10Mg(Fe), Al-Si8Cu3, Al-Si9Cu3(Fe), Al-Si9Cu3(Fe)(Zn), Al-Si11Cu2(Fe), Al-Si11Cu3(Fe), Al-Si12Cu1(Fe), and Al-Si17Cu4Mg.

6. The method for producing recycled aluminum alloy according to claim 1, wherein the multiple aluminum scraps not extracted from the above-mentioned population contain, as a chemical composition, at least one of Cu: 0.15% by mass or more, Zn: 0.25% by mass or more, Si: 0.60% by mass or more, and Ni: 0.10% by mass or more.

7. The method for producing recycled aluminum alloy according to claim 1, wherein the plurality of aluminum scraps included in the above secondary aggregate have a chemical composition comprising at least one of Cu: 1.0 mass% or less, Zn: 1.0 mass% or less, Si: 1.5 mass% or less, and Ni: 0.5 mass% or less.

8. The method for producing recycled aluminum alloy according to claim 1, wherein the above chemical composition analysis is performed on aluminum scrap in a solid state.

9. The above chemical composition analysis is based on laser-induced breakdown spectroscopy and is a method for producing recycled aluminum alloy according to claim 1.

10. A method for producing recycled aluminum alloy according to claim 1, wherein, in the above-mentioned step of production, an intermetallic compound containing the second component is produced as the above-mentioned compound by adding Mg to the molten metal.

11. The above second component includes one or more selected from the group consisting of Ti, V, Zr, and Cr. A method for producing recycled aluminum alloy according to claim 1, wherein in the above-mentioned production step, the addition of B to the molten metal produces the boride of the second component as the compound.

12. The above second component includes one or more selected from the group consisting of Ti, V, Zr, and Cr. A method for producing recycled aluminum alloy according to claim 10, wherein in the above-mentioned production step, the addition of B to the molten metal produces the boride of the second component as the compound.

13. A method for producing recycled aluminum alloy according to claim 1, further comprising the step of adjusting the composition of the molten metal after the above-mentioned compound has been removed.

14. The method for producing a recycled aluminum alloy according to claim 1, further comprising one or more melting and casting steps in which the recycled aluminum alloy obtained in the above step of obtaining the recycled aluminum alloy is melted and cast.

15. The method for producing a recycled aluminum alloy according to claim 14, wherein the molten metal obtained by melting the recycled aluminum alloy in the above melting and casting step is to be adjusted for composition.

16. The method for producing recycled aluminum alloy according to claim 2, further comprising the step of removing foreign matter other than aluminum mixed in the parent set before the step of extracting the above-mentioned secondary set.

17. The method for producing recycled aluminum alloy according to claim 2, further comprising the step of removing at least one of oil, paint, or coating adhering to the surface of a plurality of aluminum scraps in the parent set, prior to the step of extracting the above-mentioned secondary set.

18. A method for producing recycled aluminum alloy according to claim 1, wherein the chemical composition of at least some of the aluminum scrap in the above-mentioned aggregate is unknown.

19. The method for producing recycled aluminum alloy according to claim 1, further comprising the step of sampling the molten metal after the above-mentioned compound has been removed and performing a component analysis.

20. From the above population, a step of extracting one or more aluminum scraps consisting of JIS A1000 series aluminum alloys, A step of mixing the one or more aluminum scraps extracted in the aluminum scrap extraction step with the molten metal after the compound has been removed. A method for producing recycled aluminum alloy according to claim 1, further comprising:

21. A method for producing a recycled aluminum alloy material, comprising the step of plastically processing a recycled aluminum alloy obtained by the method for producing a recycled aluminum alloy according to any one of claims 1 to 20.

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