Scandium-containing aluminum alloy additive and application

Abstract

The invention discloses a scandium-containing aluminum alloy additive and a preparation method and application thereof.The scandium-containing aluminum alloy additive comprises scandium salt, sodium fluoride, dissolution promoting salt and an exothermic agent, the exothermic agent, the scandium salt, the sodium fluoride and the dissolution promoting salt are dried, prepared, mixed and pressed into blocks, and the scandium-containing aluminum alloy additive is obtained. The scandium agent salt is one of scandium fluoride, scandium chloride and scandium oxide, the dissolution promoting salt comprises one of potassium chloride, sodium chloride, potassium fluoride, calcium chloride and calcium fluoride, and the weight ratio of the heat generating agent to the scandium-containing aluminum alloy additive is larger than or equal to 30%. The scandium-containing aluminum alloy additive prepared through the method is applied to the aluminum alloy casting industry, the scandium-containing aluminum alloy can be prepared through the product at the low aluminum ingot melting temperature of about 760 DEG C, energy consumption is reduced, and the actual yield of scandium can be larger than or equal to 99.0%.

Description

Technical Field

[0001] The invention relates to an aluminum alloy additive, in particular to a scandium-containing aluminum alloy additive and application thereof. Background Art

[0002] The traditional method of producing scandium-containing aluminum alloys is to first prepare an aluminum-scandium master alloy using scandium compounds (scandium fluoride, scandium oxide, etc.), and then remelt the aluminum-scandium master alloy to prepare the scandium-containing aluminum alloy. The aluminum-scandium master alloy is expensive, with the market price of an aluminum-scandium master alloy containing 2% scandium being around 250 yuan / kg. The cost of adding scandium to aluminum alloys using the aluminum-scandium master alloy method is relatively high, and the primary Al3Sc particles in the aluminum-scandium master alloy are relatively large. During the melting process of the scandium-containing aluminum alloy, the Al3Sc particles are often difficult to dissolve, resulting in a genetic effect, which affects the performance of the aluminum alloy and does not fully utilize the role of the scandium element.

[0003] The temperature for preparing aluminum-scandium master alloy by aluminothermic reduction is generally above 880°C, which results in high energy consumption and low recovery rate.

[0004] Patent application with publication number CN114561539A discloses a method for preparing an aluminum-magnesium-scandium intermediate alloy by an aluminum-magnesium thermal reduction method using a sodium fluoride-sodium chloride-potassium chloride molten salt system. The method uses scandium fluoride as a raw material, NaF, NaCl and KCl as a molten salt system, and metallic magnesium as a reducing agent. The aluminum-magnesium-scandium intermediate alloy is prepared by an aluminum-magnesium thermal reduction method under non-vacuum conditions, comprising the following steps: (1) mixing NaF, NaCl and KCl in a certain mass ratio, grinding, and drying to prepare a mixed salt; (2) placing an aluminum ingot and a magnesium ingot in a high-purity graphite crucible until completely melted, and then adding the mixed salt in proportion until completely melted; (3) adding scandium fluoride in multiple batches, controlling the temperature at 720°C to 860°C, stirring every 10-15 minutes, and controlling the holding time at 60-120 minutes to carry out an aluminum-magnesium thermal reduction reaction. The mass ratio of the mixed salt is: NaF:NaCl:KCl=(1-3):(3-6):(3-6). The mass ratio of the mixed salt to scandium fluoride is: (2-4):1. The molten salt system of this solution is mainly used to prepare aluminum-magnesium-scandium master alloys, which are used as additives for aluminum alloys to further prepare aluminum alloys containing scandium. In the process of preparing aluminum-magnesium-scandium master alloys, there are defects such as low and unstable recovery rate of rare earth element scandium, certain oxidation losses of metallic aluminum and magnesium during the smelting process, and large primary Al3Sc particles in the aluminum-scandium master alloy. During the melting process of the scandium-containing aluminum alloy, the Al3Sc particles are often difficult to dissolve, resulting in a genetic effect, affecting the performance of the aluminum alloy, and failing to fully exert the role of the scandium element. At the same time, in the process of preparing aluminum alloys containing scandium, the price of aluminum-magnesium-scandium master alloys is generally high, which limits the application of the rare earth element scandium in aluminum alloys. Summary of the Invention

[0005] The technical problem to be solved by the present invention is to address the shortcomings of the existing technology and provide a scandium-containing aluminum alloy additive and its application. When used to prepare scandium-containing aluminum alloy, Sc can be directly added to the alloy by adding the aluminum alloy additive, thereby reducing the step of adding Sc by remelting the aluminum-scandium intermediate alloy in the traditional process, reducing the cost of adding Sc, and improving the actual recovery rate of scandium.

[0006] In order to solve the above technical problems, the technical solution adopted by the present invention is:

[0007] A scandium-containing aluminum alloy additive comprises scandium salts, sodium fluoride, and potassium chloride. The scandium-containing aluminum alloy additive also comprises a heating agent. The heating agent, the scandium salts, the sodium fluoride, and the potassium chloride are dried, batched, mixed, and pressed into blocks to obtain the scandium-containing aluminum alloy additive. The scandium salt is one of scandium fluoride, scandium chloride, and scandium oxide. The dissolution-promoting salt comprises one of potassium chloride, sodium chloride, potassium fluoride, calcium chloride, and calcium fluoride. The heating agent accounts for ≥30% by weight of the scandium-containing aluminum alloy additive.

[0008] The present invention selects scandium fluoride, sodium fluoride and potassium chloride, controls the ratio of the heating agent and presses them into blocks. The obtained scandium-containing aluminum alloy additive can be directly added to molten aluminum liquid to directly add Sc to the alloy, thereby reducing the step of adding Sc by remelting the aluminum-scandium intermediate alloy in the traditional process and reducing the cost of adding Sc.

[0009] The present invention controls the weight ratio of the exothermic agent to the scandium-containing aluminum alloy additive to ≥30%, thereby ensuring a scandium recovery rate of ≥99% when the scandium-containing aluminum alloy additive is directly added to molten aluminum. If the weight ratio of the exothermic agent to the scandium-containing aluminum alloy additive is less than 30%, the recovery rate of the scandium-containing aluminum alloy additive when directly added to the molten aluminum will be affected.

[0010] In a preferred embodiment of the present invention, the exothermic agent includes one or two of aluminum powder, potassium chlorate, sodium chlorate, sodium perchlorate, and potassium perchlorate.

[0011] The present invention develops an aluminum alloy additive (scandium agent) product, which is an organic combination packaged product of an exothermic agent (one of potassium chlorate and aluminum powder), scandium fluoride, sodium fluoride, and potassium chloride. The product is prepared by selecting a suitable exothermic agent, salt ratio, and forming and pressing method, which promotes the scandium-containing aluminum alloy additive to adapt to the 760°C melting temperature of the traditional aluminum alloy industry and to proceed forward completely without affecting the overall temperature of the aluminum liquid; the scandium-containing aluminum alloy additive only needs to be added to the surface of the aluminum liquid, and the 760°C temperature of the aluminum liquid surface, the heat emitted by the exothermic agent's own reaction, and a reasonable salt ratio can meet the requirements of rapid melting and continuous and complete aluminothermic reduction reaction. Scandium atoms will quickly disperse in the aluminum melt and float up and down in a suspended state, thereby increasing the melting rate and accelerating the aluminothermic reduction reaction process, which not only reduces energy consumption but also allows primary Al3Sc particles to be more dispersed and evenly distributed in the aluminum melt in a smaller size.

[0012] Theoretical basis: Al+ScF3=Sc+AlF3……………(1)

[0013] AlF3+3NaF=Na3AlF6…………(2)

[0014] 4Al+3O2=2Al203………………(3)

[0015] 2KClO3=2KCl+3O2↑…………(4)

[0016] Reaction (1) is an endothermic reaction, and the reaction temperature must be maintained at approximately 900°C to proceed completely. To promote the complete reaction at 760°C on the surface of the aluminum liquid, the present invention adopts several measures: 1. By selecting an organic combination of scandium fluoride, sodium fluoride, and potassium chloride, the reaction temperature can be lowered to 790-850°C, and the specific gravity of this salt combination is lower than that of the aluminum liquid. Sodium fluoride promotes reaction (2) and reduces the amount of AlF3 produced by reaction (1). To ensure that reaction (2) proceeds in the positive direction, the present invention uses potassium chloride to quickly dissolve Na3AlF6 and separate it from the aluminum liquid. 2. By selecting a suitable exothermic agent and proportion, the positive direction of reaction (1) is promoted. The present invention selects potassium chlorate or aluminum powder with a suitable ratio, and utilizes the heat emitted by the decomposition reaction of potassium chlorate or the heat emitted by the reaction of aluminum powder with oxygen in the air to provide the heat required for reaction (1); 3. By selecting a mixing and briquetting method, it is ensured that reaction (1) proceeds in a forward direction without affecting the overall temperature of the aluminum liquid. At the same time, the subsequent dispersion effect of scandium atoms is ensured. The scandium atoms will quickly disperse in the aluminum melt and float up and down in a suspended state, thereby increasing the melting speed and accelerating the reaction (1) process, not only reducing energy consumption but also allowing primary Al3Sc particles to be more dispersed and evenly distributed in the aluminum melt in a smaller size.

[0017] In a preferred embodiment of the present invention, the weight ratio of the exothermic agent to the scandium-containing aluminum alloy additive is 35% to 45%.

[0018] The scandium-containing aluminum alloy additive made from the heating agent within this range has a higher actual yield when added to molten aluminum liquid than that outside the range.

[0019] In a preferred embodiment of the present invention, the thickness of the scandium-containing aluminum alloy additive is ≤5.0 cm, preferably 0.1 to 5.0 cm.

[0020] In a preferred embodiment of the present invention, the thickness of the scandium-containing aluminum alloy additive is 0.1 to 1.0 cm.

[0021] The thickness of the scandium-containing aluminum alloy additive within this range has a higher actual yield when added to the molten aluminum liquid than that outside the range.

[0022] In a preferred embodiment of the present invention, the scandium salt is scandium fluoride, the dissolution-promoting salt is potassium chloride, and the mass ratio of the scandium fluoride, the sodium fluoride, and the potassium chloride is 1:0.15~1.5:0.35~1.5; preferably, the mass ratio of the scandium fluoride, the sodium fluoride, and the potassium chloride is 1:0.15~1:0.35~1, and the mass ratio of the sodium fluoride to the potassium chloride is 1:2.

[0023] The mass ratio of the scandium fluoride, the sodium fluoride, and the potassium chloride is 1:0.15-1.5:0.35-1.5. The scandium-containing aluminum alloy additive with a mass ratio within this range has a higher actual yield when added to the molten aluminum liquid than that outside the range.

[0024] In a preferred embodiment of the present invention, the scandium-containing aluminum alloy additive further includes an aluminum foil packaging process after pressing.

[0025] In a preferred embodiment of the present invention, the exothermic agent, the scandium salt, the sodium fluoride, and the dissolution-promoting salt are dried at a temperature of 50-150° C. for a drying time of 4 to 20 hours; and the moisture content of each raw material after drying is ≤0.1%.

[0026] In a preferred embodiment of the present invention, the scandium fluoride, the sodium fluoride, and the potassium chloride are all analytically pure; preferably, the purity of the scandium fluoride is ≥98%, and the particle size is ≥80 mesh; the purity of the aluminum powder is ≥99.8%, the active aluminum content is preferably ≥80%, and the particle size distribution is ≥100 mesh and accounts for ≥80%.

[0027] The present invention also discloses an application of the scandium-containing aluminum alloy additive in the aluminum alloy smelting and casting industry, wherein the aluminum alloy contains Sc in a mass percentage of ≤0.5%, preferably 0.001% to 0.5%.

[0028] Patent applications with publication numbers CN105821229A and CN111270096A are mainly for mixed additives of pure metal powder and flux, which are mainly suitable for adding pure metals with low melting points, brittle chemical properties and easy to break into aluminum liquid to achieve rapid alloying. The preparation process of metallic scandium is not only complicated and the price is higher than that of scandium-containing intermediate alloys, but the melting point of metallic scandium is 1540°C. This method is not applicable to the production of scandium-containing aluminum alloys.

[0029] This invention has developed an aluminum alloy additive (scandium additive) with a simple preparation process that does not require a melting or casting process. This product is suitable for directly adding Sc to aluminum alloys containing scandium. This eliminates the traditional step of remelting the intermediate alloy to add Sc, reducing the cost of adding Sc. This aluminum alloy additive is suitable for the production of most aluminum alloys containing scandium (Sc ≤ 0.5%).

[0030] The present invention develops an aluminum alloy additive (scandium agent) product, which can complete the preparation of scandium-containing aluminum alloy at a low aluminum ingot melting temperature of about 760°C, not only reducing energy consumption but also achieving a scandium recovery rate of ≥99.0%.

[0031] Compared with the prior art, the present invention has the following beneficial effects:

[0032] (1) High scandium recovery rate: The present invention develops an aluminum alloy additive (scandium agent) product, which can complete the preparation of scandium-containing aluminum alloy at a low aluminum ingot melting temperature of about 760°C, which not only reduces energy consumption but also can achieve a scandium recovery rate of ≥99.0%.

[0033] (2) Low cost and more guaranteed performance of scandium-containing aluminum alloy: The present invention develops an aluminum alloy additive (scandium agent) product, which only needs to be added to the surface of the aluminum liquid. The temperature of the aluminum liquid and the heat emitted by the aluminum liquid itself can satisfy the continuous melting and aluminothermic reduction reactions. The scandium agent will quickly disperse in the aluminum melt and float up and down in a suspended state, thereby increasing the melting speed and accelerating the aluminothermic reduction reaction process, which not only reduces energy consumption but also enables Al3Sc particles to be more dispersed and evenly distributed in the aluminum melt.

[0034] (3) The existing technology in the aluminum alloy casting industry is highly applicable: the casting temperature in the existing aluminum alloy casting industry is generally controlled at around 760°C. The scandium-containing aluminum alloy additive only needs to be added to the surface of the aluminum liquid. The aluminum liquid temperature and the heat it emits can satisfy the continuous melting and aluminothermic reduction reactions, and has little effect on the overall temperature of the aluminum liquid. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] Figure 1This is a photo of the scandium-containing aluminum alloy additive prepared in one embodiment of the present invention (the scandium-containing aluminum alloy additive is surrounded by aluminum foil).

[0036] Figure 2 This is a photo of the scandium-containing aluminum alloy additive prepared in one embodiment of the present invention being added into aluminum liquid.

[0037] Figure 3 This is a photograph of the scandium-containing aluminum alloy additive prepared in one embodiment of the present invention after being added to molten aluminum. DETAILED DESCRIPTION

[0038] Example 1: Scandium is added in the form of a scandium-containing aluminum alloy additive to carry out aluminothermic reduction to produce the scandium-containing aluminum alloy 7A48.

[0039] (1) The scandium agent ratio is:

[0040] First furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.64kg aluminum powder.

[0041] Second furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.64kg potassium chlorate.

[0042] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 4 cakes are pressed into each cake, weighing 537.5g and with a thickness of about 0.8cm. They are then packed with 0.02mm aluminum foil. Figure 1 (1) Simulate the traditional aluminum alloy casting industry (2) Implementation process:

[0043] Equipment: medium frequency furnace with a capacity of 400kg;

[0044] Implementation of the heat: 2 heats;

[0045] Ingredients:

[0046]

[0047] Step 1: Add aluminum ingots, melt and stir until flat, temperature 750-770℃;

[0048] Step 2: Adding aluminum alloy additives containing scandium, such as Figure 2 As shown, after melting Figure 3 As shown, keep warm for 30 minutes;

[0049] Step 3: Stir for 20 minutes;

[0050] Step 4: Remove the salt residue;

[0051] Step 5: Add cold material, aluminum copper, aluminum manganese, aluminum zirconium, and aluminum titanium, temperature 760-780℃, keep warm for 10 minutes;

[0052] Step 6: mechanical stirring for 20 min, mechanical stirring speed 150±10 r / min, argon 2 L / min, temperature 760-780°C;

[0053] Step 7: Add the master alloy, zinc ingot and magnesium ingot, stir and level them manually, and make sure there are no unleveled alloy blocks at the bottom of the furnace. Heat to 760-770℃ and keep warm for 30min.

[0054] Step 8: mechanical stirring for 10 min, mechanical stirring speed 150±10 r / min, argon 2 L / min;

[0055] Step 9: Keep warm for 30 minutes

[0056] Step 10: Refining for 25 minutes, blowing the refining agent into the aluminum liquid with argon; ---

[0057] Step 11: Temperature 770-780℃, remove the slag adhered to the inner wall of the crucible and the slag on the surface of the melt, leaving no dead corners;

[0058] Step 12: pouring the furnace, the aluminum liquid before pouring is 770-780℃, and the holding furnace is 730℃;

[0059] Step 13: Add aluminum titanium boron wire;

[0060] Step 14: Refining with Ar gas for 15 minutes;

[0061] Step 15: Let it stand for 20 minutes;

[0062] Step 16: The aluminum liquid discharge temperature is 700-710℃, and the aluminum liquid temperature on the plate is guaranteed to be 680-690℃.

[0063] Step 17: Casting, casting speed 130mm / min.

[0064] (3) Implementation results: The recovery rate of scandium is about 99%.

[0065] Example 2: Scandium is added in the form of a scandium-containing aluminum alloy additive to perform aluminothermic reduction to produce the scandium-containing aluminum alloy 7A48.

[0066] (1) The scandium agent ratio is:

[0067] The first furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg aluminum powder.

[0068] Second furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg potassium chlorate.

[0069] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 594g, with a thickness of about 0.8cm, and are packaged with 0.02mm aluminum foil.

[0070] (2) Implementation process (implementation process is the same as that of Example 1):

[0071] (3) Implementation results: The recovery rate of scandium is about 100%.

[0072] Example 3: Scandium is added in the form of a scandium-containing aluminum alloy additive to perform aluminothermic reduction to produce the scandium-containing aluminum alloy 7A48.

[0073] (1) The scandium agent ratio is:

[0074] First furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.01kg aluminum powder.

[0075] Second furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.01kg potassium chlorate.

[0076] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 672g, with a thickness of about 1.0cm, and are packaged with 0.02mm aluminum foil.

[0077] (2) Implementation process (implementation process is the same as that of Example 1):

[0078] (3) Implementation results: The recovery rate of scandium is about 100%.

[0079] Example 4: Scandium is added in the form of a scandium-containing aluminum alloy additive to perform aluminothermic reduction to produce the scandium-containing aluminum alloy 7A48.

[0080] (1) The scandium agent ratio is:

[0081] First furnace: 0.94kg scandium fluoride, 1.00kg sodium fluoride, 1.00kg potassium chloride, 3.00kg aluminum powder.

[0082] Second furnace: 0.94kg scandium fluoride, 1.00kg sodium fluoride, 1.00kg potassium chloride, 3.00kg potassium chlorate.

[0083] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 742.5g, with a thickness of about 1.1cm, and are packaged with 0.02mm aluminum foil.

[0084] (2) Implementation process (implementation process is the same as that of Example 1):

[0085] (3) Implementation results: The recovery rate of scandium is about 100%.

[0086] Example 5: Scandium is added in the form of a scandium-containing aluminum alloy additive and aluminothermic reduction is performed to produce a pure aluminum alloy containing 0.5% scandium.

[0087] (1) The scandium agent ratio is:

[0088] The first furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg aluminum powder.

[0089] Second furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg potassium chlorate.

[0090] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 594g, with a thickness of about 0.8cm, and are packaged with 0.02mm aluminum foil.

[0091] (2) Implementation process:

[0092] Equipment: medium frequency furnace with a capacity of 100kg;

[0093] Implementation of the heat: 2 heats;

[0094]

[0095] Step 1: Add aluminum ingots, melt and stir until flat, temperature 750-770℃;

[0096] Step 2: Keep the mixture warm and let it stand for 5 minutes, then scrape off the scum on the surface of the aluminum liquid;

[0097] Step 2: Add the scandium-containing aluminum alloy additive, melt it and keep it warm for 20 minutes;

[0098] Step 3: Stir for 15 minutes;

[0099] Step 4: Keep warm and let it stand for 10 minutes, then remove the salt residue;

[0100] Step 5: Casting into plates (using water-cooled molds).

[0101] (3) Implementation results: The recovery rate of scandium is about 100%.

[0102] Comparative Example 1

[0103] Scandium agent ratio:

[0104] First furnace: 0.94kg scandium fluoride, 0.09kg sodium fluoride, 0.28kg potassium chloride, 0.56kg aluminum powder.

[0105] Second furnace: 0.94kg scandium fluoride, 0.09kg sodium fluoride, 0.28kg potassium chloride, 0.56kg potassium chlorate.

[0106] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 3 cakes are pressed, each weighing about 623.3g and with a thickness of about 0.9cm. The cakes are then packaged with 0.02mm aluminum foil.

[0107] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield in the first heat was 80%, and the scandium yield in the second heat was 72%. A significant difference between this comparative example and Example 1 is that the ratio of scandium fluoride, sodium fluoride, and potassium chloride in the scandium-containing aluminum alloy additive is 1:0.1:0.3.

[0108] Comparative Example 2

[0109] Scandium agent ratio:

[0110] First furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.62kg aluminum powder.

[0111] Second furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.62kg potassium chlorate.

[0112] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 4 cakes are pressed, each weighing about 532.5g and with a thickness of about 0.8cm. The cakes are then packaged with 0.02mm aluminum foil.

[0113] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium recovery rate in the first heat was 98%, and the scandium recovery rate in the second heat was 96%. A significant difference between this comparative example and Example 1 is that the aluminum powder in the scandium-containing aluminum alloy additive now accounts for 29% by weight.

[0114] Comparative Example 3

[0115] Scandium agent ratio:

[0116] First furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.64kg aluminum powder.

[0117] Second furnace: 0.94kg scandium fluoride, 0.19kg sodium fluoride, 0.38kg potassium chloride, 0.64kg potassium chlorate.

[0118] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of one cake is pressed into the cake, which weighs about 2150g and is about 5.5cm thick. It is then packaged with 0.02mm aluminum foil.

[0119] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield in the first heat was 98.5%, and the scandium yield in the second heat was 98.2%. A significant difference between this comparative example and Example 1 is that the aluminum powder in the scandium-containing aluminum alloy additive now accounts for 29% by weight.

[0120] Comparative Example 4

[0121] Scandium agent ratio:

[0122] First furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.85kg aluminum powder.

[0123] Second furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.85kg potassium chlorate.

[0124] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 586g, with a thickness of about 0.8cm, and are packaged with 0.02mm aluminum foil.

[0125] Production verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium recovery rate of the first heat was 98.8%, and the scandium recovery rate of the second heat was 98.3%. This comparative example differs from Example 2 in that the proportion of the exothermic agent is 29%.

[0126] Comparative Example 5

[0127] Scandium agent ratio:

[0128] The first furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg aluminum powder.

[0129] Second furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg potassium chlorate.

[0130] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of one cake is pressed into the cake, the cake weight is 2970g, the cake thickness is about 5.0cm, and it is packaged with 0.02mm aluminum foil.

[0131] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield in the first heat was 99.5%, and the scandium yield in the second heat was 99.2%. This comparative example differs from Example 2 in that the cake thickness is 5.0 cm.

[0132] Comparative Example 6

[0133] Scandium agent ratio:

[0134] The first furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg aluminum powder.

[0135] Second furnace: 0.94kg scandium fluoride, 0.38kg sodium fluoride, 0.76kg potassium chloride, 0.89kg potassium chlorate.

[0136] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of one cake is pressed into the cake, the cake weight is 2970g, the cake thickness is about 7.0cm, and it is packaged with 0.02mm aluminum foil.

[0137] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield in the first heat was 93.6%, and the scandium yield in the second heat was 91.3%. This comparative example differs from Example 2 in that the cake thickness is 7.0 cm.

[0138] Comparative Example 7

[0139] Scandium agent ratio:

[0140] First furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 0.96kg aluminum powder.

[0141] Second furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 0.96kg potassium chlorate.

[0142] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 662g, with a thickness of about 1.0cm, and are packaged with 0.02mm aluminum foil.

[0143] Production verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium recovery rate of the first heat was 98.6%, and the scandium recovery rate of the second heat was 98.1%. This comparative example differs from Example 3 in that the proportion of the exothermic agent is 29%.

[0144] Comparative Example 8

[0145] Scandium agent ratio:

[0146] First furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.57kg aluminum powder.

[0147] Second furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.57kg potassium chlorate.

[0148] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 784g, with a thickness of about 1.2cm, and are packaged with 0.02mm aluminum foil.

[0149] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium recovery rate in the first heat was 100.0%, and the scandium recovery rate in the second heat was 100.0%. This comparative example differs from Example 2 in that the proportion of the exothermic agent is 40%.

[0150] Comparative Example 9

[0151] Scandium agent ratio:

[0152] First furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.01kg aluminum powder.

[0153] Second furnace: 0.94kg scandium fluoride, 0.47kg sodium fluoride, 0.94kg potassium chloride, 1.01kg potassium chlorate.

[0154] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of one cake is pressed into the cake, the cake weight is 3360g, the cake thickness is about 8.0cm, and it is packaged with 0.02mm aluminum foil.

[0155] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield of the first heat was 93.1%, and the scandium yield of the second heat was 92.2%. This comparative example differs from Example 3 in that the cake thickness is 8.0 cm.

[0156] Comparative Example 10

[0157] Scandium agent ratio:

[0158] First furnace: 0.94kg scandium fluoride, 1.00kg sodium fluoride, 1.00kg potassium chloride, 0.93kg aluminum powder.

[0159] Second furnace: 0.94kg scandium fluoride, 1.00kg sodium fluoride, 1.00kg potassium chloride, 0.93kg potassium chlorate.

[0160] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of 5 cakes are pressed, each weighing 774g and with a thickness of about 1.3cm. The cakes are then packaged with 0.02mm aluminum foil.

[0161] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium recovery rate of the first heat was 96.5%, and the scandium recovery rate of the second heat was 93.8%. This comparative example differs from Example 4 in that the proportion of the exothermic agent is 24%.

[0162] Comparative Example 11

[0163] Scandium agent ratio:

[0164] First furnace: 0.94kg scandium fluoride, 1kg sodium fluoride, 1kg potassium chloride, 3kg aluminum powder.

[0165] Second furnace: 0.94kg scandium fluoride, 1kg sodium fluoride, 1kg potassium chloride, 3kg potassium chlorate.

[0166] Production process of scandium-containing aluminum alloy additive: The raw materials are dried, batched, mixed, and pressed into cakes. A total of one cake is pressed into the cake, the cake weight is 5940g, the cake thickness is about 10.0cm, and it is packaged with 0.02mm aluminum foil.

[0167] Production Verification: Scandium-containing aluminum alloy 7A48 was produced according to the process of Example 1, with an addition temperature of 750-770°C. The scandium yield in the first heat was 93%, and the scandium yield in the second heat was 91%. This comparative example differs from Example 4 in that the thickness of the scandium agent pressed cake was 10.0 cm.

Claims

1. A scandium-containing aluminum alloy additive, comprising scandium salts, sodium fluoride, and a dissolution-promoting salt, characterized in that: The scandium-containing aluminum alloy additive also includes a heat-generating agent. The heat-generating agent, the scandium agent salt, the sodium fluoride, and the dissolution-promoting salt are dried, batched, mixed, and pressed into blocks to obtain the scandium-containing aluminum alloy additive. The scandium agent salt is one of scandium fluoride, scandium chloride, and scandium oxide. The dissolution-promoting salt includes one of potassium chloride, sodium chloride, potassium fluoride, calcium chloride, and calcium fluoride. The heat-generating agent accounts for ≥30% by weight of the scandium-containing aluminum alloy additive.

2. The scandium-containing aluminum alloy additive according to claim 1, characterized in that The exothermic agent includes one or two of aluminum powder, potassium chlorate, sodium chlorate, sodium perchlorate, and potassium perchlorate.

3. The scandium-containing aluminum alloy additive according to claim 1, characterized in that The weight ratio of the exothermic agent to the scandium-containing aluminum alloy additive is 35% to 45%.

4. The scandium-containing aluminum alloy additive according to claim 1, characterized in that The thickness of the scandium-containing aluminum alloy additive is ≤5.0 cm.

5. The scandium-containing aluminum alloy additive according to claim 4, characterized in that The thickness of the scandium-containing aluminum alloy additive is 0.1 to 1.0 cm.

6. The scandium-containing aluminum alloy additive according to any one of claims 1 to 5, characterized in that: The scandium salt is scandium fluoride, the dissolution-promoting salt is potassium chloride, and the mass ratio of the scandium fluoride, the sodium fluoride, and the potassium chloride is 1:0.15~1.5:0.35~1.5; preferably, the mass ratio of the scandium fluoride, the sodium fluoride, and the potassium chloride is 1:0.15~1:0.35~1, and the mass ratio of the sodium fluoride and the potassium chloride is 1:

2.

7. The scandium-containing aluminum alloy additive according to any one of claims 1 to 5, characterized in that: The scandium-containing aluminum alloy additive further includes an aluminum foil packaging process after pressing.

8. The scandium-containing aluminum alloy additive according to any one of claims 1 to 5, characterized in that: The exothermic agent, the scandium salt, the sodium fluoride and the dissolution-promoting salt are dried at a temperature of 50-150° C. and a drying time of 4 to 20 hours; and the moisture content of each raw material after drying is ≤0.1%.

9. The scandium-containing aluminum alloy additive according to claim 6, characterized in that The scandium fluoride, the sodium fluoride, and the potassium chloride are all analytically pure; preferably, the purity of the scandium fluoride is ≥98%, and the particle size is ≥80 mesh; the purity of the aluminum powder is ≥99.8%, the active aluminum content is preferably ≥80%, and the particle size distribution is ≥100 mesh, accounting for ≥80%.

10. Use of the scandium-containing aluminum alloy additive according to any one of claims 1 to 9 in the aluminum alloy casting industry, characterized in that: The aluminum alloy contains Sc in a mass percentage of ≤0.5%.

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