Method for preparing high-strength and high-toughness aluminum-lanthanum metal alloy through waste aluminum blending
By employing gradient cooling treatment and the use of fluorides, the problem of unstable performance of waste aluminum alloys was solved, enabling the preparation of high-strength, high-toughness aluminum-lanthanum alloys suitable for high-end structural components.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- CHINALCO GUANGXI NONFERROUS RARE EARTH DEV CO LTD
- Filing Date
- 2026-02-27
- Publication Date
- 2026-05-15
AI Technical Summary
Existing technologies make it difficult to effectively utilize waste aluminum to prepare high-performance rare earth aluminum alloys, resulting in large performance fluctuations, high costs, and difficulty in meeting the requirements of high-end structural components.
Using scrap aluminum, aluminum ingots, aluminum fluoride, lanthanum fluoride, and calcium fluoride as raw materials, a high-strength, high-toughness aluminum-lanthanum metal alloy is formed through gradient cooling treatment. Fluorides are used to remove impurities and promote the uniform precipitation of intermetallic compounds.
Stable production of high-performance aluminum-lanthanum alloys has been achieved, reducing production costs and improving the tensile strength and yield strength of the alloys, making them suitable for high-end structural components.
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Figure CN122038833A_ABST
Abstract
Description
Technical Field
[0001] This invention belongs to the field of rare earth aluminum alloy production technology, specifically relating to a method for preparing high-strength and high-toughness aluminum-lanthanum metal alloy by using waste aluminum as a binder. Background Technology
[0002] Aluminum and its alloys are widely used in aerospace, transportation, and electronics industries due to their low density, high specific strength, and good corrosion resistance. With the continuous growth in aluminum product consumption, the accumulation of scrap aluminum is also increasing dramatically, including scrapped car parts, aluminum alloy doors and windows, aluminum plates, aluminum pipes, aluminum profiles, aluminum wires, and aluminum scrap. Efficient recycling of scrap aluminum is of great strategic and economic significance for conserving mineral resources, reducing energy consumption, and minimizing environmental pollution. However, current scrap aluminum recycling often involves downgrading and reusing it for cast aluminum alloys or ordinary wrought aluminum materials with low performance requirements, making it difficult to achieve high-value-added utilization.
[0003] Adding rare earth elements to aluminum alloys is considered an effective way to improve their overall performance. Rare earth elements can form thermally stable intermetallic compounds with aluminum and other alloying elements, significantly refining grains and purifying the melt. Therefore, rare earth aluminum alloys theoretically possess high strength, high toughness, good thermal stability, and corrosion resistance, making them potential materials for high-end structural components. However, the preparation and research of rare earth aluminum alloys mostly use high-purity primary aluminum and rare earth metals as raw materials, and it is extremely rare to use scrap aluminum in production. This is because using scrap aluminum results in significant performance fluctuations in rare earth aluminum alloys, making it impossible to guarantee stable product quality. Furthermore, it increases the amount of rare earth elements used, potentially increasing production costs instead of reducing them. Summary of the Invention
[0004] To address the aforementioned shortcomings, this invention discloses a method for preparing high-strength and high-toughness aluminum-lanthanum alloys by doping with waste aluminum. This method fully utilizes waste aluminum to prepare high-strength and high-toughness aluminum-lanthanum alloys, which can not only obtain high-performance rare earth aluminum alloys but also effectively reduce production costs.
[0005] This invention is achieved using the following technical solution: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum includes the following steps: (1) Weigh the raw materials according to the following weight proportions: 15-25 parts of waste aluminum, 70-80 parts of aluminum ingots, 1-2 parts of aluminum fluoride, 2-8 parts of lanthanum fluoride, and 3-5 parts of calcium fluoride; (2) Take waste aluminum and heat it in a gas-fired aluminum melting furnace to 800°C. Then add aluminum fluoride and mix. Then add calcium fluoride, which accounts for two-thirds of the total amount of calcium fluoride, and mix. Then keep it at 800-850°C to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 750-800℃. Then add aluminum ingots and keep it at 5-10 min. Then add lanthanum fluoride and keep it at 10-15 min. Then add the remaining calcium fluoride and keep it at 20-25 min to obtain the alloy solution. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and keep it at 800℃ for 3 to 5 minutes. Then, cool it down to 300 to 320℃ at a rate of 5 to 10℃ / s, keep it at that temperature for 5 to 10 minutes, and then let it cool naturally to room temperature to obtain an aluminum-lanthanum metal alloy. The tensile strength of the aluminum-lanthanum metal alloy is 280 to 330 MPa and the yield strength is 260 to 300 MPa.
[0006] Furthermore, the scrap aluminum mentioned in step (1) can be any one or more combinations of scrapped car parts, aluminum alloy doors and windows, aluminum plates, aluminum pipes, aluminum profiles, aluminum wires, and aluminum scrap.
[0007] Furthermore, the aluminum purity of the waste aluminum mentioned in step (1) is above 97%.
[0008] Furthermore, in step (2), the waste aluminum is crushed into fragments and placed in a gas-fired aluminum melting furnace. The furnace is heated to 450–550°C and held for 10–20 minutes, then heated to 800°C. The fragments are 30–50 mm long and 30–50 mm wide. Heating the waste aluminum fragments to 450–550°C and then holding them at that temperature effectively removes the organic matter originally attached to the surface of the waste aluminum, which is beneficial for subsequent smelting.
[0009] Furthermore, in step (3), the aluminum ingots are divided into 2 to 5 portions and added to the waste aluminum melt in batches. After each batch of aluminum ingots is added, it is kept warm for 2 to 5 minutes before adding the next batch. Adding aluminum ingots in batches is beneficial for mixing and melting with the waste aluminum melt.
[0010] Furthermore, during the processing described in step (3), the operating frequency of the gas-fired aluminum melting furnace is controlled at 30Hz.
[0011] Furthermore, in step (3), the addition time of lanthanum fluoride is controlled within 5 to 8 minutes, and the addition time of calcium fluoride is controlled within 5 minutes.
[0012] Furthermore, in step (4), the alloy solution is subjected to gradient cooling. The specific procedure is as follows: the first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 5 to 10℃ / second. Through rapid quenching, the alloying elements are dissolved in the aluminum matrix to the maximum extent to form a supersaturated solid solution. After the first gradient cooling is completed, the second gradient cooling is carried out directly without holding. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 1 to 3℃ / minute. After cooling to 300℃, the temperature is held for 10 to 15 minutes, and then the third gradient cooling is carried out. Holding at 300℃ can make the fine second phase precipitate uniformly and diffusely, which significantly improves the strength. The third gradient cooling is furnace cooling or natural cooling at 300℃ to achieve stress release. Through slow cooling, the thermal stress caused by temperature difference is minimized, thereby improving the dimensional stability and toughness of the alloy.
[0013] Compared with existing technologies, this technical solution has the following advantages: This invention utilizes waste aluminum to prepare high-performance aluminum alloys. First, waste aluminum is melted and aluminum fluoride and calcium fluoride are added for smelting. This not only reduces the smelting temperature but also removes various impurities carried in the waste aluminum. Then, pure aluminum ingots are added for mixing and melting, which dilutes the impurities and helps to minimize the uncertainties brought by waste aluminum, thus ensuring the stability of the final alloy performance.
[0014] Meanwhile, the present invention also adds lanthanum fluoride and calcium fluoride to the alloy melt for refining. Lanthanum fluoride is added after the scrap aluminum and aluminum ingots are fully mixed and melted, so that it is evenly distributed and fully contacts the melt to react and form a metallic intermediate phase, which can effectively improve the tensile strength and yield strength of the alloy. At the same time, lanthanum fluoride and the subsequently added calcium fluoride can promote the formation of calcium silicate and other slags such as Si, S and P in the melt, thereby effectively removing impurities. Attached Figure Description
[0015] Figure 1 These are metallographic images of the aluminum-lanthanum alloy prepared by the method described in Example 1.
[0016] Figure 2 The image shows a metallographic image of the aluminum-lanthanum alloy prepared by the method described in Comparative Example 2. Detailed Implementation
[0017] The present invention is further illustrated by the following examples, but these are not intended to limit the invention. Specific experimental conditions and methods not specified in the following examples are generally conventional methods well known to those skilled in the art.
[0018] Example 1: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 20 parts of scrap aluminum, 75 parts of aluminum ingots, 1 part of aluminum fluoride, 6 parts of lanthanum fluoride, and 4 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 97.6%, and the scrap aluminum includes aluminum tubes, aluminum profiles, aluminum wires, and aluminum scrap. (2) Take waste aluminum, break it into pieces with a length of 45 mm and a width of 45 mm, place them in a gas-fired aluminum melting furnace, heat to 500℃ and keep warm for 15 min, then continue heating to 800℃, then add aluminum fluoride and mix, then add calcium fluoride accounting for two-thirds of the total amount of calcium fluoride and mix, then keep warm at 820℃ to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 780°C. The working frequency of the gas-fired aluminum melting furnace is controlled at 30Hz. Then, divide the aluminum ingots into 3 equal parts and add them to the waste aluminum melt in batches. After each batch of aluminum ingots is added, keep it at 3 minutes before adding the next batch of aluminum ingots. Then add lanthanum fluoride and keep it at 12 minutes. Then add the remaining calcium fluoride and keep it at 22 minutes to obtain the alloy solution. The addition time of lanthanum fluoride is controlled at 6 minutes and the addition time of calcium fluoride is controlled at 5 minutes. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and use gradient cooling to obtain aluminum-lanthanum metal alloy. The first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 8℃ / second. After the first gradient cooling is completed, the second gradient cooling is carried out directly without heat preservation. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 2℃ / minute. After cooling to 300℃, heat preservation is carried out for 12 minutes, and then the third gradient cooling is carried out. The third gradient cooling is natural cooling at 300℃.
[0019] Example 2: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 15 parts of scrap aluminum, 70 parts of aluminum ingots, 1.5 parts of aluminum fluoride, 2 parts of lanthanum fluoride, and 3 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 98.2%, and the scrap aluminum includes aluminum plates, aluminum tubes, and aluminum profiles; (2) Take waste aluminum, break it into fragments with a length of 30 mm and a width of 30 mm, place them in a gas-fired aluminum melting furnace, heat to 450℃ and keep warm for 20 min, then continue heating to 800℃, then add aluminum fluoride and mix, then add calcium fluoride accounting for two-thirds of the total amount of calcium fluoride and mix, then keep warm at 800℃ to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 750°C. The working frequency of the gas-fired aluminum melting furnace is controlled at 30Hz. Then, divide the aluminum ingots into two equal parts and add them to the waste aluminum melt in batches. After each batch of aluminum ingots is added, keep it at 5 minutes before adding the next batch of aluminum ingots. Then add lanthanum fluoride and keep it at 10 minutes. Then add the remaining calcium fluoride and keep it at 20 minutes to obtain the alloy solution. The addition time of lanthanum fluoride is controlled at 5 minutes and the addition time of calcium fluoride is controlled at 4 minutes. (4) Take the alloy solution obtained in step (3) and place it in a heat-holding kiln and use gradient cooling to obtain aluminum-lanthanum metal alloy. The first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 5℃ / second. After the first gradient cooling is completed, the second gradient cooling is carried out directly without heat holding. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 1℃ / minute. After cooling to 300℃, heat holding is carried out for 10 minutes, and then the third gradient cooling is carried out. The third gradient cooling is carried out with the furnace at 300℃.
[0020] Example 3: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 22 parts of scrap aluminum, 72 parts of aluminum ingots, 1.8 parts of aluminum fluoride, 7 parts of lanthanum fluoride, and 4.5 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 97.9%, and the scrap aluminum includes aluminum plates, aluminum tubes, and aluminum profiles; (2) Take waste aluminum, break it into fragments with a length of 40 mm and a width of 40 mm, place them in a gas-fired aluminum melting furnace, heat to 520℃ and keep warm for 15 min, then continue heating to 800℃, then add aluminum fluoride and mix, then add calcium fluoride accounting for two-thirds of the total amount of calcium fluoride and mix, then keep warm at 830℃ to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 760°C. The working frequency of the gas-fired aluminum melting furnace is controlled at 30Hz. Then, divide the aluminum ingots into 4 equal parts and add them to the waste aluminum melt in batches. After each batch of aluminum ingots is added, keep it at 2 minutes before adding the next batch of aluminum ingots. Then add lanthanum fluoride and keep it at 12 minutes. Then add the remaining calcium fluoride and keep it at 25 minutes to obtain the alloy solution. The addition time of lanthanum fluoride is controlled at 7 minutes and the addition time of calcium fluoride is controlled at 5 minutes. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and use gradient cooling to obtain aluminum-lanthanum metal alloy. The first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 6℃ / second. After the first gradient cooling is completed, the second gradient cooling is carried out directly without heat preservation. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 1.5℃ / minute. After cooling to 300℃, heat preservation is carried out for 12 minutes, and then the third gradient cooling is carried out. The third gradient cooling is natural cooling at 300℃.
[0021] Example 4: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 25 parts of scrap aluminum, 80 parts of aluminum ingots, 2 parts of aluminum fluoride, 8 parts of lanthanum fluoride, and 5 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 97.2%, and the scrap aluminum includes scrapped car parts, aluminum plates, and aluminum scrap. (2) Take waste aluminum, break it into pieces with a length of 50 mm and a width of 50 mm, place them in a gas-fired aluminum melting furnace, heat to 550℃ and keep warm for 10 min, then continue heating to 800℃, then add aluminum fluoride and mix, then add calcium fluoride accounting for two-thirds of the total amount of calcium fluoride and mix, then keep warm at 850℃ to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 800℃. The working frequency of the gas-fired aluminum melting furnace is controlled at 30Hz. Then, divide the aluminum ingots into 5 equal parts and add them to the waste aluminum melt in batches. After each batch of aluminum ingots is added, keep it at 2 minutes before adding the next batch of aluminum ingots. Then add lanthanum fluoride and keep it at 15 minutes. Then add the remaining calcium fluoride and keep it at 25 minutes to obtain the alloy solution. The addition time of lanthanum fluoride is controlled at 8 minutes and the addition time of calcium fluoride is controlled at 5 minutes. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and use gradient cooling to obtain aluminum-lanthanum metal alloy. The first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 10℃ / second. After the first gradient cooling is completed, the second gradient cooling is carried out directly without heat preservation. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 3℃ / minute. After cooling to 300℃, heat preservation is carried out for 15 minutes, and then the third gradient cooling is carried out. The third gradient cooling is natural cooling at 300℃.
[0022] Comparative Example 1: A method for preparing a high-strength, high-toughness aluminum-lanthanum alloy using waste aluminum as a binder, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 20 parts of scrap aluminum, 75 parts of aluminum ingots, 1 part of aluminum fluoride, 6 parts of lanthanum fluoride, and 4 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 97.6%, and the scrap aluminum includes aluminum tubes, aluminum profiles, aluminum wires, and aluminum scrap. (2) Take waste aluminum, break it into fragments with a length of 45 mm and a width of 45 mm, place them in a gas-fired aluminum melting furnace and heat them to 800°C. Then add aluminum ingots, aluminum fluoride, lanthanum fluoride and calcium fluoride in sequence, mix them and keep them at 800°C for 30 min to obtain an alloy solution. (3) Take the alloy solution obtained in step (2) and place it in a heat preservation kiln and keep it at 800℃ for 4 min. Then, cool it down to 305℃ at a rate of 6℃ / s, keep it at 8 min, and then cool it naturally to room temperature to obtain an aluminum-lanthanum metal alloy.
[0023] Comparative Example 2: A method for preparing high-strength and high-toughness aluminum-lanthanum alloy by doping with waste aluminum, comprising the following steps: (1) Weigh the raw materials according to the following weight proportions: 20 parts of scrap aluminum, 75 parts of aluminum ingots, 1 part of aluminum fluoride, 6 parts of lanthanum fluoride, and 4 parts of calcium fluoride; the aluminum purity of the scrap aluminum is 97.6%, and the scrap aluminum includes aluminum tubes, aluminum profiles, aluminum wires, and aluminum scrap. (2) Take waste aluminum, break it into fragments with a length of 45 mm and a width of 45 mm, place them in a gas-fired aluminum melting furnace, heat to 500°C and hold for 15 min, then continue heating to 800°C, then add aluminum fluoride and mix, and then hold at 820°C to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 780°C. The working frequency of the gas-fired aluminum melting furnace is controlled at 30Hz. Then add aluminum ingots to the waste aluminum melt and keep it at 8min. Then add lanthanum fluoride and keep it at 12min. Then add calcium fluoride and keep it at 22min to obtain the alloy solution. The addition time of lanthanum fluoride is controlled at 6min and the addition time of calcium fluoride is controlled at 5min. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and keep it at 800°C for 4 min. Then, cool it down to 305°C at a rate of 6°C / s, keep it at 8 min, and then cool it naturally to room temperature to obtain an aluminum-lanthanum metal alloy.
[0024] Experimental example: Aluminum-lanthanum alloys were prepared according to the methods described in Examples 1-4 and Comparative Examples 1-2, and the tensile strength and yield strength of the aluminum-lanthanum alloys were tested. The specific results are shown in Table 1.
[0025] Table 1. Detection results of aluminum-lanthanum alloys prepared by different methods
[0026] As shown in Table 1, the aluminum-lanthanum alloy prepared according to the method of this invention has better tensile strength and yield strength. In contrast, in Comparative Example 1, directly mixing and melting scrap aluminum, aluminum ingots, aluminum fluoride, lanthanum fluoride, and calcium fluoride easily leads to uneven distribution of aluminum fluoride, lanthanum fluoride, and calcium fluoride in the melt, failing to achieve refining and impurity removal. Furthermore, it hinders the contact between lanthanum fluoride and the melt, resulting in insufficient reaction and a decrease in the lanthanum content in the alloy, failing to form a sufficient strengthening phase and thus affecting the alloy's performance. In Comparative Example 2, calcium fluoride was not added during the smelting of scrap aluminum, but only added during the smelting of aluminum ingots and lanthanum fluoride for impurity removal. This prevents the effective removal of impurities entrained in the scrap aluminum, thus affecting the contact reaction between lanthanum fluoride and the melt, and consequently hindering the improvement of alloy performance. Moreover, the alloy solution in Comparative Example 2 did not employ a gradient cooling method, which is not conducive to the uniform and fine precipitation of intermetallic compounds from the supersaturated solid solution, reducing the strengthening effect of the alloy. Figure 1 and Figure 2 As shown, the grain size of the alloy prepared by the method of the present invention is smaller and more uniformly distributed than that of Comparative Example 2, resulting in better comprehensive mechanical properties.
[0027] Furthermore, it should be understood that although this specification describes embodiments, not every embodiment contains only one independent technical solution. This narrative style is merely for clarity. Those skilled in the art should consider the specification as a whole, and the technical solutions in each embodiment can also be appropriately combined to form other embodiments that can be understood by those skilled in the art.
Claims
1. A method for preparing high-strength, high-toughness aluminum-lanthanum alloy by doping with waste aluminum, characterized in that: Includes the following steps: (1) Weigh the raw materials according to the following weight proportions: 15-25 parts of waste aluminum, 70-80 parts of aluminum ingots, 1-2 parts of aluminum fluoride, 2-8 parts of lanthanum fluoride, and 3-5 parts of calcium fluoride; (2) Take waste aluminum and heat it in a gas-fired aluminum melting furnace to 800°C. Then add aluminum fluoride and mix. Then add calcium fluoride, which accounts for two-thirds of the total amount of calcium fluoride, and mix. Then keep it at 800-850°C to obtain waste aluminum melt. (3) After removing the scum floating on the surface of the waste aluminum melt obtained in step (2), add it to the gas-fired aluminum melting furnace and keep it at 750-800℃. Then add aluminum ingots and keep it at 5-10 min. Then add lanthanum fluoride and keep it at 10-15 min. Then add the remaining calcium fluoride and keep it at 20-25 min to obtain the alloy solution. (4) Take the alloy solution obtained in step (3) and place it in a heat-preserving kiln and keep it at 800℃ for 3 to 5 minutes. Then, cool it down to 300 to 320℃ at a rate of 5 to 10℃ / s, keep it at that temperature for 5 to 10 minutes, and then let it cool naturally to room temperature to obtain an aluminum-lanthanum metal alloy. The tensile strength of the aluminum-lanthanum metal alloy is 280 to 330 MPa and the yield strength is 260 to 300 MPa.
2. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by doping with waste aluminum according to claim 1, characterized in that: The scrap aluminum mentioned in step (1) can be any one or more combinations of scrapped car parts, aluminum alloy doors and windows, aluminum plates, aluminum pipes, aluminum profiles, aluminum wires, and aluminum scrap.
3. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by blending with waste aluminum according to claim 1, characterized in that: The aluminum purity of the waste aluminum mentioned in step (1) is above 97%.
4. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by blending with waste aluminum according to claim 1, characterized in that: In step (2), waste aluminum is crushed into fragments and placed in a gas-fired aluminum melting furnace and heated to 450-550°C. The temperature is then maintained for 10-20 minutes, and then heated to 800°C. The fragments are 30-50 mm long and 30-50 mm wide.
5. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by blending with waste aluminum according to claim 1, characterized in that: In step (3), the aluminum ingots are divided into 2 to 5 portions and added to the waste aluminum melt in batches. After each batch of aluminum ingots is added, it is kept warm for 2 to 5 minutes before adding the next batch of aluminum ingots.
6. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by blending with waste aluminum according to claim 1, characterized in that: During the process described in step (3), the operating frequency of the gas-fired aluminum melting furnace is controlled at 30Hz.
7. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by blending with waste aluminum according to claim 1, characterized in that: In step (3), the addition time of lanthanum fluoride is controlled within 5 to 8 minutes, and the addition time of calcium fluoride is controlled within 5 minutes.
8. The method for preparing high-strength, high-toughness aluminum-lanthanum alloy by doping with waste aluminum according to claim 1, characterized in that: In step (4), the alloy solution is cooled in a gradient manner. The first gradient cooling is from 800℃ to 400℃, and the cooling rate is controlled at 5 to 10℃ / second. After the first gradient cooling is completed, the second gradient cooling is carried out directly without holding the temperature. The second gradient cooling is from 400℃ to 300℃, and the cooling rate is controlled at 1 to 3℃ / minute. After cooling to 300℃, the temperature is held for 10 to 15 minutes, and then the third gradient cooling is carried out. The third gradient cooling is carried out at 300℃ with the furnace or by natural cooling.