Efficient refining agent, preparation method and application of efficient refining agent in production of high-performance aluminum alloy material

Abstract

The invention discloses an efficient refining agent, a preparation method and application of the efficient refining agent in production of a high-performance aluminum alloy material, and the efficient refining agent comprises the following components in percentage by mass: 10-20 wt% of a fluorine salt compound, 60-80 wt% of a chlorine salt compound, 3-8 wt% of a rare earth compound and 5-10 wt% of a slag former; the preparation method comprises the steps of inert gas shielding drying, ball-milling mixing, muffle furnace sintering, screening and the like, and the prepared efficient refining agent is applied to production of high-performance aluminum alloy materials. By improving the formula and the preparation process route of the refining agent, the content of excessive impurity elements of the refining agent is effectively reduced, effective control over non-gas impurities of the aluminum alloy melt is achieved, the mechanical property of an aluminum alloy product is greatly improved, and the refining agent has the remarkable characteristics of being short in refining time, high in production efficiency and free of environmental pollution.

Description

[Technical field]

[0001] The invention relates to the field of aluminum alloy production, and in particular to a high-efficiency refining agent, a preparation method and application thereof in the production of high-performance aluminum alloy materials. [Background technology]

[0002] Aluminum alloys have been widely used in aerospace, automobile manufacturing, electronic equipment and many other fields due to their advantages such as light weight, high strength and good corrosion resistance. In the production process of aluminum alloys, refining is an extremely critical link. The purpose of refining is to remove gases and impurities in the aluminum alloy melt to improve the quality and performance of the aluminum alloy.

[0003] Traditional refining agents have many shortcomings. For example, some refining agents have unsatisfactory refining effects and cannot effectively remove tiny inclusions and dissolved hydrogen in the melt, resulting in defects such as pores and inclusions in aluminum alloy products, which seriously affect their mechanical properties and processing properties. In addition, some refining agents will produce a large amount of harmful gases and waste slag during use, which pollutes the environment and increases production costs and the difficulty of subsequent treatment. Therefore, the development of an efficient, environmentally friendly and low-cost refining agent is of great significance for the production of high-performance aluminum alloy materials.

[0004] The Chinese invention patent with the patent publication number CN111424186A and the publication date of July 17, 2020, discloses a high-efficiency composite refining agent for recycled aluminum melt, including an impurity removal component and a refinement component, the impurity removal component accounts for 70-95%, and the refinement component accounts for 5-30%. The components are mixed evenly and smelted in a melting furnace. The molten material is condensed to room temperature and then crushed. The powder and granular material is sieved and vacuum sealed to obtain the high-efficiency composite refining agent of the present invention. Although the refining agent has a certain effect in removing impurities and hydrogen, the removal effect may still be less than ideal for some small-sized inclusions.

[0005] The disclosure of the above background technology content is only used to assist in understanding the inventive concept and technical solution of the present invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above content has been disclosed on the filing date of this patent application, the above background technology should not be used to evaluate the novelty and creativity of the present application. [Summary of the invention]

[0006] The purpose of the present invention is to provide a high-efficiency refining agent, a preparation method and application thereof in the production of high-performance aluminum alloy materials, so as to solve the technical problems existing in the above-mentioned prior art.

[0007] To this end, the present invention adopts the following technical solutions:

[0008] A high-efficiency refining agent, comprising the following components by mass percentage:

[0009] 10-20wt% of fluoride salt compounds, 60-80wt% of chloride salt compounds, 3-8wt% of rare earth compounds and 5-10wt% of slag forming agent;

[0010] The fluoride salt compound includes at least two of KF, Na3A1F6, and Na2SiF6;

[0011] The chloride salt compound includes at least two of MgCl2, NaCl, LiCl or KCl;

[0012] The rare earth compound includes one or more of Y2O3, Er2O3 and Sc2O3;

[0013] The slag-forming agent is BaCO3.

[0014] The technical principles of the raw material components of a high-efficiency refining agent described in the present invention are as follows:

[0015] Fluoride salt compounds, chloride salt compounds, rare earth compounds and slag-forming agents have significant synergistic effects in the aluminum alloy refining process, jointly promoting the optimization of refining effects and providing key support for the preparation of high-quality aluminum alloys.

[0016] Fluoride salt compounds have lower lattice energy, and their ionic bonds are more easily broken at high temperatures, allowing them to melt at relatively low temperatures. For example, in the crystal structure of Na3A1F6, the bond energy of the aluminum-fluoride ion bond is relatively weak. At the melting temperature of aluminum alloys, the thermal energy is sufficient to overcome the constraints of these ionic bonds, causing it to melt and form a molten salt system. When multiple fluoride salts are mixed, they form a eutectic mixture, further lowering the melting point. The fluoride ions in fluoride salts have strong electronegativity and can electrostatically attract metal ions or positive charge centers on the surface of metal oxides and non-metallic inclusions. Taking alumina inclusions as an example, fluoride ions can bond with Al on the surface of alumina. 3+ The ions undergo exchange reactions to form substances such as fluoroaluminates, thereby changing the surface properties of the inclusions, making them more easily adsorbed and entrained by the molten salt system, and ultimately removed from the aluminum alloy melt.

[0017] Chloride compounds have the ability to dissolve and adsorb metal oxides and non-metallic inclusions in the melt, and they complement and synergize with fluoride compounds. Chloride ions in chloride salts also have strong electronegativity. At high temperatures, chloride salts melt to form a molten salt system, and chloride ions can exchange with ions on the surface of inclusions. For example, for magnesium oxide inclusions, chloride ions can react with Mg 2+Ions are exchanged, causing magnesium oxide to dissolve in the chloride molten salt. At the same time, the chloride molten salt also has the ability to adsorb other metal oxides and non-metallic inclusions. This is because the ions on the surface of the inclusions are more easily surrounded by the surrounding chloride ions and cations in the molten salt environment, and are thus adsorbed into the molten salt system. After melting, the chloride salt will increase the ion concentration in the melt, thereby changing the ionic environment of the melt. This change will affect the interaction between ions in the melt, and then change the physical and chemical properties of the melt. For example, an increase in ion concentration will weaken the interaction between metal ions, resulting in a decrease in the viscosity of the melt and an increase in fluidity. This is conducive to the diffusion of the refining agent in the melt and its full contact with impurities, and together with fluoride salt compounds, it will improve the impurity removal efficiency and optimize the quality of aluminum alloys.

[0018] During the solidification process of aluminum alloys, rare earth compounds can serve as the core of heterogeneous nucleation. When the melt temperature is reduced to near the solidification point, the atomic arrangement on the surface of the rare earth compound has certain similarities with the atomic arrangement of the aluminum alloy, but there are differences. This difference enables the rare earth compound to provide more nucleation sites. Aluminum alloy atoms will preferentially gather and begin to crystallize at these sites, thereby increasing the number of crystal nuclei. As crystallization proceeds, more crystal nuclei will limit the growth of grains, ultimately leading to grain refinement. Rare earth elements have high chemical activity, and the electronic layer structure of their atoms makes it easy for them to react chemically with some impurity elements in the aluminum alloy melt. For example, rare earth elements can undergo redox reactions or form chemical bonds with impurity elements such as Fe and Si. Taking the reaction between rare earth elements and iron as an example, rare earth iron compounds (such as REFe2 and other forms) may be formed. These compounds have a high melting point. During the refining process, due to their different density from the aluminum alloy melt, they will more easily float into the slag phase and be removed, thereby improving the purity of the aluminum alloy melt. This works synergistically with the impurity removal effect of fluoride and chloride compounds to ensure the refining quality of the aluminum alloy.

[0019] The principle of slag-forming agent adsorbing impurities to form slag phase: At high temperature, BaCO3 will decompose to form BaO and CO2. The generated BaO has high chemical activity and can react chemically with impurities such as oxides and non-metallic inclusions in the aluminum alloy melt. For example, BaO can react with Al2O3 to form BaAl2O4, and react with SiO2 to form BaSiO3, etc. These reaction products will form a slag phase together with other unreacted BaO and adsorbed inclusions. The chemical composition and structure of the formed slag phase products will affect the properties of the slag phase. For example, the formation of products such as BaSiO3 may reduce the viscosity of the slag phase and make the slag phase looser. This is because the crystal structure and chemical bond properties of barium silicate weaken the interaction between particles in the slag phase, resulting in a decrease in viscosity. The loose slag phase is conducive to floating and separation during the refining process, which is convenient for subsequent slag removal operations, and cooperates with other components to improve the refining efficiency and ensure that the aluminum alloy refining reaches high quality standards.

[0020] Fluoride salts, chloride salts, rare earth compounds and slag-forming agents work closely and synergistically in aluminum alloy refining through their own unique mechanisms of action. Fluoride salt compounds lay the foundation for the refining process by lowering the melting point and promoting the adsorption of inclusions in the early stage. Chloride salt compounds cooperate with fluoride salt compounds by virtue of their ability to dissolve and adsorb inclusions and improve the viscosity and fluidity of the melt, further enhancing the effect of impurity removal. The two work together in the melt purification link. Rare earth compounds refine grains through heterogeneous nucleation during the solidification stage and remove impurities through chemical reactions. Their action time and mode are different from those of fluoride salts and chloride salts, but they are jointly committed to improving the quality of aluminum alloys and achieving synergy at different stages and levels. The slag phase formed by the slag-forming agent BaCO3 is closely connected with the effects of the previous components through efficient adsorption of impurities and floating separation in the later stage of refining, which completely removes impurities from the melt and completes the closed-loop synergy of the entire refining process. By working together on key links such as melting point control, impurity removal, grain refinement and slag phase separation, an efficient refining system is constructed, fully demonstrating the importance and necessity of the synergistic effect produced by the rational combination of various components of the refining agent for the preparation of high-quality aluminum alloys.

[0021] The present invention also provides a method for preparing a high-efficiency refining agent, comprising the following steps:

[0022] Step 1: Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, and dry them under the protection of inert gas to remove moisture;

[0023] Step 2: Mix the pretreated raw material powders evenly according to the set ratio and put them into a ball mill, and add grinding balls for ball milling;

[0024] Step 3: The ball-milled powder is placed in a crucible, and then the crucible is placed in a muffle furnace for sintering;

[0025] Step 4: The finished product is cooled to room temperature, sieved through a vibrating screen to remove unqualified large particles, and the finished refining agent is obtained and packaged for storage.

[0026] Preferably, in step 1, the inert gas is argon or nitrogen, the drying temperature is set at 80-120° C., and the drying time is 2-4 hours.

[0027] Preferably, during the ball milling mixing in step 2, the ball-to-material ratio is set to 10:1-20:1, the rotation speed is set to 200-500rpm, and the ball milling time is 1-2h.

[0028] Preferably, the sintering in step 3 is carried out at a temperature of 500-700° C. for 1-3 hours.

[0029] Preferably, in step 4, the mesh size of the vibrating screen is 100-200 mesh, and the particle size range of the finished refining agent is 0.075 mm-0.150 mm.

[0030] The technical principle of the preparation method of a high-efficiency refining agent described in the present invention is as follows:

[0031] The moisture in the raw materials may have adverse effects in the subsequent processing, such as causing the raw materials to agglomerate and affecting the chemical reaction. Therefore, it is necessary to remove the moisture through drying to ensure the purity and processing performance of the raw materials. Drying under the protection of inert gas is to prevent the rare earth compounds from oxidizing with oxygen in the air during the drying process. Rare earth compounds have high chemical activity and are easily oxidized in an aerobic environment, thereby changing their chemical properties and affecting the final performance of the refining agent.

[0032] Putting different raw material powders into the ball mill according to the set ratio for ball milling can make various raw materials fully mixed under the action of mechanical force. Through the impact, extrusion and grinding of the grinding balls, the particles of different raw materials contact and collide with each other, gradually achieving uniform distribution, ensuring the uniformity of the components of the refining agent, avoiding local component differences, and thus ensuring the stability and reliability of the refining agent performance. During the ball milling process, a series of physical and chemical reactions will occur between the raw material particles. For example, the cold welding and fracture process between the particles can make the atoms of different raw materials diffuse and mix with each other to a certain extent, which helps to form a more stable compound or alloy structure. At the same time, the energy generated by ball milling may also activate some chemical reactions that were originally difficult to occur, further optimizing the performance of the refining agent.

[0033] Placing the ball-milled powder into a crucible and sintering it in a muffle furnace can further bind the powder particles tightly. At high temperatures, the surface atoms of the powder particles diffuse and rearrange to form a more stable structure, enhancing the overall strength and stability of the refining agent and preventing powder shedding or uneven dispersion during use. The sintering process can promote a more complete chemical reaction between the raw materials. Some components that did not fully react during the ball milling process have more opportunities to continue to react in a high-temperature sintering environment, further optimizing the chemical composition and properties of the refining agent and improving its ability to adsorb and remove impurities in the aluminum alloy melt.

[0034] Vibrating screen screening can remove unqualified large particles and control the particle size of the finished refining agent within the range of 0.075mm-0.150mm. The appropriate particle size is crucial for the distribution and effect of the refining agent in the aluminum alloy melt. Uniform particle size can ensure that the refining agent is better diffused in the melt and fully contacted with impurities, thereby improving the refining efficiency.

[0035] From the perspective of the synergistic effect of the entire preparation process, the drying step provides a pure and stable raw material basis for subsequent ball milling, sintering and other steps, avoiding the degradation of raw material performance due to moisture and oxidation problems, and ensuring that each component can participate in subsequent reactions in the best state. The ball milling process not only achieves uniform mixing of raw materials, but the physical and chemical reactions it triggers also lay the foundation for the early chemical structure of the sintering process, allowing the various components to further react and fuse more efficiently during sintering, thereby enhancing the performance of the refining agent. Sintering consolidates and sublimates the ball milling effect, allowing the refining agent to form a more stable and compact structure, improving its strength and chemical activity, so that it can better synergize the refining effect on the aluminum alloy melt when used. The screening process ensures the uniformity of the particle size of the finished refining agent, allowing it to be more evenly distributed in the aluminum alloy melt. Together with the previous drying, ball milling and sintering processes, it ensures that the refining agent can be in the best state and performance from raw material processing to the final product, and can fully adsorb and remove impurities in the aluminum alloy melt, optimize the physical and chemical properties of the melt, and achieve efficient refining. This fully reflects the importance and value of close cooperation among all links in the preparation process and coordinated optimization of the refining agent performance to meet the needs of aluminum alloy refining.

[0036] The present invention also provides a use of a high-efficiency refining agent of the above raw material combination or a high-efficiency refining agent prepared by the above preparation method in the production of high-performance aluminum alloy materials, comprising the following steps:

[0037] S1. Heat the aluminum raw material until it is melted to obtain aluminum liquid, add the mixed waste aluminum melt and pre-treated aluminum liquid to the aluminum liquid, and when the obtained mixed aluminum liquid is heated to 700-800°C, add a high-efficiency refining agent to the mixed aluminum liquid and stir and mix;

[0038] S2. Refining gas is blown into the mixed aluminum liquid with high-efficiency refining agent for refining. When impurities float to the surface of the mixed aluminum melt, the slag is removed. Then, the slag is filtered after standing for 15-20 minutes. Finally, the aluminum liquid is poured out of the furnace to complete the entire use process.

[0039] Preferably, the addition amount of the high-efficiency refining agent is 0.5-2% of the mass of the mixed aluminum liquid; the ratio of the aluminum liquid melted and pretreated from scrap aluminum to the aluminum raw material is 0-0.3:1.

[0040] Preferably, the refining gas is argon or nitrogen.

[0041] The present invention also provides an aluminum alloy prepared by using the above-mentioned high-efficiency refining agent in the production of high-performance aluminum alloy materials.

[0042] The beneficial effects of the present invention compared with the prior art include:

[0043] 1. The present invention can more effectively adsorb and remove gaseous impurities in aluminum alloy melts through a specific preparation process and a reasonable raw material formula. The refining agent of the present invention can penetrate deep into the melt to exert its effect due to its components. For example, the refining agent powder after ball milling has a finer particle size and a more uniform component distribution, which can diffuse better in the melt and fully contact with impurities. It can not only remove impurities on the surface, but also effectively treat impurities deep inside the melt, thereby improving the depth and comprehensiveness of refining. The gas produced by the decomposition of fluoride salt compounds at high temperatures can adsorb hydrogen, and chloride salt compounds and slag-forming agents can also help gaseous impurities enter the slag phase and be removed, thereby significantly reducing the hydrogen content in the aluminum alloy melt, and the hydrogen content of the aluminum alloy material can be reduced to below 0.20ml / 100gAl.

[0044] 2. The rare earth compound is added to the refining agent obtained by the present invention as a raw material. During the solidification process of the aluminum alloy, the rare earth element can serve as the core of heterogeneous nucleation, increase the number of crystal nuclei, and thus refine the grains. The refined grains can improve the strength, hardness, toughness and other mechanical properties of the aluminum alloy.

[0045] 3. Compared with common refining agents, the refining agent of the present invention contains composite components such as chloride salt compounds, fluoride salt compounds, rare earth compounds and slag forming agents. Rare earth elements have high chemical activity and can react chemically with some impurity elements in the aluminum alloy melt. For example, rare earth elements can form high melting point compounds with impurities such as iron and silicon. These compounds are easily floated into the slag phase and removed during the refining process, further improving the purity of the aluminum alloy melt. And BaCO3 decomposes at high temperature to produce BaO and CO2. BaO has high chemical activity and can absorb impurities such as oxides and non-metallic inclusions in the aluminum alloy melt, and form a slag phase together with other reaction products. The decomposition products of BaCO3 can change the properties of the slag phase, such as reducing the viscosity of the slag phase and making the slag phase more loose. This is conducive to the separation and floating of the slag phase during the refining process, facilitates the subsequent slag removal operation, improves the refining efficiency, and the properties of this slag phase are conducive to the subsequent waste slag treatment, such as recycling or harmless treatment, reducing the negative impact of waste slag on the environment.

[0046] 4. The prior art has problems such as long refining time and complex process, resulting in low production efficiency. The preparation method of the present invention is relatively simple and efficient. For example, by adopting ball milling and sintering process, a refining agent with excellent performance can be prepared in a relatively short time. At the same time, due to its good refining effect during use, the refining time of aluminum alloy can be shortened from the original 30-40min refining time to 15-20min, thereby improving the efficiency of the entire production process and reducing production costs. By optimizing the composition of the refining agent, reasonably selecting raw materials such as fluoride salts, chloride salts and rare earth compounds, and determining their appropriate proportions, the amount of some expensive raw materials (such as some rare earth compounds) can be reduced while ensuring the refining effect. For example, by accurately controlling the content of rare earth compounds at 3-8wt%, it can not only play its role in refining grains and removing impurities, but also avoid the cost increase caused by excessive use. Compared with the situation in which a large amount of rare earth compounds are used in some prior arts, the cost of raw materials is reduced.

Brief Description of the Drawings

[0047] Figure 1 This is a picture of the aluminum alloy material product produced by the refining agent prepared in Example 1 of the present invention. [Specific implementation method]

[0048] The foregoing has broadly described the features and technical advantages of the present invention so that the detailed description of the present invention can be better understood. Other features and advantages of the present invention will be described below. It should be understood by those skilled in the art that the disclosed concepts and specific embodiments can be easily used as a basis for modifying or designing other structures to accomplish the same purpose of the present invention. It should also be recognized by those skilled in the art that such equivalent constructions do not deviate from the spirit and scope of the present invention. The novel features, structures and methods of operation, and further objects and advantages that are considered to be characteristic of the present invention will be better understood from the following description in conjunction with the accompanying drawings. However, it should be deeply recognized that each feature provided is only for description and illustration, and is not intended to limit the definition of the present invention.

[0049] Example 1

[0050] A high-efficiency refining agent, comprising the following components by mass percentage:

[0051] Fluoride salt compounds: KF is 3wt%, Na3A1F6 is 7wt%, Na2SiF6 is 5wt%;

[0052] Chloride salt compounds: MgCl2 is 10wt%, NaCl is 40wt%, LiCl is 10wt%, KCl is 10wt%;

[0053] Rare earth compounds: Y2O3 is 4wt%, Er2O3 is 2wt%, Sc2O3 is 2wt%,

[0054] The slag-forming agent BaCO3 is 7wt%.

[0055] A method for preparing a high-efficiency refining agent comprises the following steps:

[0056] Step 1: Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, and dry them under the protection of argon gas. The temperature is set at 110°C and the drying time is 2.5 hours to remove moisture;

[0057] Step 2: Mix the pretreated raw material powders evenly and put them into a ball mill, add grinding balls, set the ball-to-material ratio to 15:1, the speed to 350 rpm, the ball milling time to 1.5 h, and perform ball milling mixing;

[0058] Step 3: The ball-milled powder is placed in a crucible, and then the crucible is placed in a muffle furnace and sintered at 600 °C for 2 h;

[0059] Step 4: The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 150. The particle size range of the finished refining agent is between 0.120 mm. Unqualified large particles are removed to obtain the finished refining agent, which is then packaged and put into storage.

[0060] Example 2

[0061] A high-efficiency refining agent, comprising the following components by mass percentage:

[0062] Fluoride salt compounds: KF is 8wt%, Na3AlF6 is 6wt%, Na2SiF6 is 6wt%;

[0063] Chloride compounds: MgCl2 is 18wt%, NaCl is 35wt%, LiCl is 6wt%, and KCl is 7wt%;

[0064] Rare earth compounds: Y2O3 is 3wt%, Er2O3 is 3wt%, and Sc2O3 is 2wt%;

[0065] The slag-forming agent BaCO3 is 6wt%.

[0066] A method for preparing a high-efficiency refining agent comprises the following steps:

[0067] Step 1: Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, and dry them under the protection of argon gas. The temperature is set at 80°C and the drying time is 4 hours to remove moisture;

[0068] Step 2: Mix the pretreated raw material powders evenly and put them into a ball mill, add grinding balls, set the ball-to-material ratio to 10:1, the speed to 200 rpm, the ball milling time to 2 h, and perform ball milling mixing;

[0069] Step 3: The ball-milled powder is placed in a crucible, and then the crucible is placed in a muffle furnace and sintered at 500 °C for 3 h;

[0070] Step 4: The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 200. The particle size range of the finished refining agent is between 0.150 mm. Unqualified large particles are removed to obtain the finished refining agent, which is then packaged and put into storage.

[0071] Example 3

[0072] A high-efficiency refining agent, comprising the following components by mass percentage:

[0073] Fluoride salt compounds: KF is 5wt%, Na3A1F6 is 8wt%, Na2SiF6 is 7wt%;

[0074] Chloride compounds: MgCl2 is 20wt%, NaCl is 32wt%, LiCl is 8wt%, and KCl is 7wt%;

[0075] Rare earth compounds: Y2O3 is 4wt%, Er2O3 is 2wt%, Sc2O3 is 2wt%,

[0076] The slag-forming agent BaCO3 is 5wt%.

[0077] A method for preparing a high-efficiency refining agent comprises the following steps:

[0078] Step 1: Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, and dry them under the protection of argon gas. The temperature is set at 120°C and the drying time is 2 hours to remove moisture;

[0079] Step 2: Mix the pretreated raw material powders evenly and put them into a ball mill, add grinding balls, set the ball-to-material ratio to 20:1, the speed to 500 rpm, the ball milling time to 1 h, and perform ball milling mixing;

[0080] Step 3: The ball-milled powder is placed in a crucible, and then the crucible is placed in a muffle furnace and sintered at 700 °C for 1 h;

[0081] Step 4: The finished product is cooled to room temperature and sieved through a vibrating screen with a mesh size of 100. The particle size range of the finished refining agent is between 0.075 mm. Unqualified large particles are removed to obtain the finished refining agent, which is then packaged and put into storage.

[0082] Comparative Example 1

[0083] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of Na2SiF6.

[0084] Comparative Example 2

[0085] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of Na3A1F6.

[0086] Comparative Example 3

[0087] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by KF of equal mass.

[0088] Comparative Example 4

[0089] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of BaCO3.

[0090] Comparative Example 5

[0091] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of Y2O3.

[0092] Comparative Example 6

[0093] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of Er2O3.

[0094] Comparative Example 7

[0095] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by an equal mass of Sc2O3.

[0096] Comparative Example 8

[0097] It is basically the same as Example 1, except that in the high-efficiency refining agent component, NaCl is replaced by equal masses of Y2O3, Er2O3 and Sc2O3.

[0098] The refining agents provided in Examples 1-3 and Comparative Examples 1-8 are used to produce high-performance aluminum alloy materials for refining, and the specific application process is as follows:

[0099] S1. Heat 7 tons of raw aluminum to melt to obtain aluminum liquid, add 3 tons of mixed scrap aluminum melted and pre-treated aluminum liquid to the aluminum liquid, and when the mixed aluminum liquid is heated to 750°C, add a high-efficiency refining agent to the mixed aluminum liquid in an amount of 1% of the mass of the mixed aluminum liquid, and stir and mix;

[0100] S2. Blow argon into the mixed aluminum liquid with high-efficiency refining agent for refining. When impurities float to the surface of the mixed aluminum melt, remove the slag. Then let it stand for 20 minutes and filter the slag on the bottom. Finally, the aluminum liquid is poured out of the furnace to complete the whole use process.

[0101] The aluminum alloy materials obtained in Examples 1-3 were tested with an OBGS1000 direct reading spectrometer to measure the removal level of impurity elements. The results are shown in Table 1. The aluminum alloy materials obtained in Examples 1-3 and Comparative Examples 1-8 were tested on-site with an HDA-V hydrogen meter to measure the hydrogen content of the aluminum liquid in the furnace before and after refining. The results are shown in Table 2. The aluminum alloy product produced by the refining agent prepared in Example 1 is shown in Figure 2. Figure 1 .

[0102] Table 1: Results of removal levels of impurity elements before and after refining in Examples 1-3

[0103]

[0104]

[0105] Table 2: Test results of aluminum alloy materials obtained in Examples 1-3 and Comparative Examples 1-8

[0106]

[0107] From the above experimental results, it can be seen that in the aluminum alloy refining process, each component of the refining agent plays a vital and irreplaceable role, and together ensures the achievement of the refining effect.

[0108] For example, in Comparative Example 1, after Na2SiF6 is replaced by NaCl, from the perspective of slag-making principle, the mechanism of Na2SiF6 reacting with impurities to form slag during the slag-making process is unique. As mentioned above, the fluorine ions in fluoride salt compounds have strong electronegativity and can electrostatically attract metal ions or positive charge centers on the surface of metal oxides and non-metallic inclusions. Taking aluminum oxide inclusions as an example, fluorine ions can react with Al 3+ Ions undergo exchange reactions to form fluoroaluminates and other substances, which change the surface properties of inclusions, making them easier to be adsorbed and entrained by the molten salt system, and thus removed from the aluminum alloy melt. The resulting slag differs in physical and chemical properties from the slag generated by the NaCl reaction. In terms of impurity removal, NaCl cannot completely replace the role of Na2SiF6, resulting in poor impurity removal. At the same time, in terms of hydrogen removal, based on the characteristics of fluoride salt compounds, the original auxiliary hydrogen removal effect of Na2SiF6 is also affected by being replaced by NaCl, resulting in the inability to effectively reduce the hydrogen content in the molten metal, which in turn affects the quality of the metal.

[0109] In Comparative Example 2, when Na3A1F6 is replaced by NaCl, Na3A1F6 has a unique advantage in fluxing. Fluoride salt compounds have lower lattice energy, and their ionic bonds are easier to break at high temperatures, so they can melt at relatively low temperatures, and a mixture of multiple fluoride salts will form a eutectic mixture to further reduce the melting point, which makes the refining agent have good fluidity and reactivity at a lower temperature. Although NaCl also has a certain fluxing effect, it cannot fully achieve the effect of Na3A1F6, so the fluidity and reactivity of the refining agent at the refining temperature are reduced, which in turn affects the impurity removal and dehydrogenation effects. In terms of impurity removal, the specific reaction mechanism of Na3A1F6 participating in impurity removal is changed, so that some impurities cannot be effectively removed as in Example 1, resulting in a relatively high impurity content in the metal.

[0110] In Comparative Example 3, after KF was replaced by NaCl, in terms of hydrogen removal, since KF has the ability to react with hydrogen to generate volatile substances, which is based on the special effect of fluoride ions and metal ions in fluoride salt compounds, and NaCl is relatively weak in this regard, the hydrogen removal mechanism is destroyed, and the hydrogen content in the metal liquid is difficult to be effectively controlled, increasing the risk of defects such as pores in the metal. At the same time, in terms of impurity removal, the original ability of KF to react with certain specific impurities disappears, making it impossible to fully remove these impurities during the refining process, affecting the purity of the metal.

[0111] In comparative example 4, after BaCO3 is replaced by NaCl, from the perspective of slag-making principle, BaCO3 is an efficient slag-making agent. At high temperature, BaCO3 will undergo a decomposition reaction to generate BaO and CO2. The generated BaO has high chemical activity and can react chemically with impurities such as oxides and non-metallic inclusions in the aluminum alloy melt. For example, BaO can react with Al2O3 to generate BaAl2O4, and react with SiO2 to generate BaSiO3, etc. These reaction products will form a slag phase together with other unreacted BaO and adsorbed inclusions. The generated slag has excellent floating and stability performance and can effectively separate impurities from the metal liquid. However, NaCl is insufficient in the reaction of impurities corresponding to BaCO3, and it is impossible to generate a sufficient amount of slag with good performance, resulting in a significant deterioration in the slag generation and impurity removal effect, and a significant increase in the impurity content in the metal, which seriously affects the quality of the metal.

[0112] In comparative examples 5 to 7, after Y2O3, Er2O3 and Sc2O3 are replaced by NaCl respectively, in terms of grain refinement, since Y2O3, Er2O3 and Sc2O3 can refine the metal grains, the principle is that during the solidification of aluminum alloy, rare earth compounds can serve as the core of heterogeneous nucleation. When the melt temperature is reduced to near the solidification point, the atomic arrangement on the surface of the rare earth compound has a certain similarity with the atomic arrangement of the aluminum alloy, but there are differences. This difference enables the rare earth compound to provide more nucleation sites. The aluminum alloy atoms will preferentially gather and begin to crystallize at these sites, thereby increasing the number of crystal nuclei. As the crystallization proceeds, more crystal nuclei will limit the growth of grains, ultimately leading to grain refinement. NaCl does not have this function, so the grain refinement effect of the metal is lost, the metal's organizational structure becomes relatively coarse, and the mechanical properties and processing properties are adversely affected. In terms of impurity removal, the unique roles of Y2O3, Er2O3 and Sc2O3 in participating in the impurity removal reaction disappear after being replaced by NaCl. Rare earth elements have high chemical activity, and the electronic layer structure of their atoms makes it easy for them to react chemically with some impurity elements in the aluminum alloy melt. For example, rare earth elements can undergo redox reactions or form chemical bonds with impurity elements such as Fe and Si. Taking the reaction between rare earth elements and iron as an example, rare earth iron compounds (such as REFe2 and other forms) may be formed. These compounds have high melting points. During the refining process, due to their different densities from the aluminum alloy melt, they are more likely to float into the slag phase and be removed, thereby improving the purity of the aluminum alloy melt. NaCl cannot achieve these effects, which hinders the impurity removal process, and the impurity content in the metal cannot be effectively reduced, thereby reducing the quality of the metal.

[0113] In Comparative Example 8, after Y2O3, Er2O3 and Sc2O3 were replaced by NaCl at the same time, since these three rare earth compounds play an important role in refining grains and assisting in removing impurities in the refining agent, their absence almost completely lost the grain refining effect of the metal, the metal structure became coarse and uneven, and the mechanical properties were seriously reduced. At the same time, in terms of impurity removal, due to the lack of the auxiliary role of these three rare earth compounds, the impurity removal effect was greatly affected, the impurity content in the metal increased significantly, and the refined metal could not meet the requirements of high-quality products.

[0114] In summary, each component has a unique and irreplaceable role in the refining process, and they cooperate and work together to ensure the realization of the refining effect. In the comparative example, when NaCl is used to replace other components, due to the different action mechanisms of each component, the key links such as slag making, hydrogen removal, fluxing, and grain refinement in the refining process are disturbed and damaged to varying degrees, resulting in a significant deterioration of the refining effect, and the refining level of Example 1 cannot be reached, which fully illustrates the importance of the reasonable matching and synergistic effect of the components of the refining agent for obtaining high-quality refined metals.

[0115] Those skilled in the art will recognize that numerous variations to the above description are possible, and that the examples are intended only to describe one or more specific implementations.

[0116] Although what is considered as exemplary embodiments of the present invention has been described and described, it will be understood by those skilled in the art that various changes and substitutions may be made thereto without departing from the spirit of the present invention. In addition, many modifications may be made to adapt specific situations to the teachings of the present invention without departing from the central concept of the present invention described herein. Therefore, the present invention is not limited to the specific embodiments disclosed herein, but the present invention may also include all embodiments and their equivalents that fall within the scope of the present invention.

Claims

1. A high-efficiency refining agent, characterized in that: Calculated by mass percentage, it includes the following components: 10-20wt% of fluoride salt compounds, 60-80wt% of chloride salt compounds, 3-8wt% of rare earth compounds and 5-10wt% of slag forming agent; The fluoride salt compound includes at least two of KF, Na3A1F6, and Na2SiF6; The chloride salt compound includes at least two of MgCl2, NaCl, LiCl or KCl; The rare earth compound includes one or more of Y2O3, Er2O3 and Sc2O3; The slag-forming agent is BaCO3.

2. A method for preparing a high-efficiency refining agent as claimed in claim 1, characterized in that: The following steps are involved: Step 1: Weigh the raw materials of each component of the refining agent according to the mass fraction ratio, and dry them under the protection of inert gas to remove moisture; Step 2: Mix the pretreated raw material powders in a set ratio and put them into a ball mill, and add grinding balls for ball milling; Step 3: The ball-milled powder is placed in a crucible, and then the crucible is placed in a muffle furnace for sintering; Step 4: The finished product is cooled to room temperature, sieved through a vibrating screen to remove unqualified large particles, and the finished refining agent is obtained and packaged for storage.

3. The method for preparing a high-efficiency refining agent according to claim 2, characterized in that: In step 1, the inert gas is argon or nitrogen, the drying temperature is set at 80-120° C., and the drying time is 2-4 hours.

4. The method for preparing a high-efficiency refining agent according to claim 2, characterized in that: In step 2, the ball-to-material ratio is set to 10:1-20:1, the rotation speed is set to 200-500 rpm, and the ball milling time is 1-2 h.

5. The method for preparing a high-efficiency refining agent according to claim 2, characterized in that: In the step 3, the sintering is carried out at a temperature of 500-700° C. for 1-3 hours.

6. The method for preparing a high-efficiency refining agent according to claim 2, characterized in that: In step 4, the mesh size of the vibrating screen is 100-200 mesh, and the particle size range of the obtained refining agent product is 0.075mm-0.150mm.

7. Use of the high-efficiency refining agent according to claim 1 or the high-efficiency refining agent prepared by the preparation method of the high-efficiency refining agent according to any one of claims 2 to 6 in the production of high-performance aluminum alloy materials, characterized in that: The steps include: S1. Heat the aluminum raw material until it is melted to obtain aluminum liquid, add the mixed waste aluminum melt and pre-treated aluminum liquid to the aluminum liquid, and when the obtained mixed aluminum liquid is heated to 700-800°C, add a high-efficiency refining agent to the mixed aluminum liquid and stir and mix; S2. Refining gas is blown into the mixed aluminum liquid with high-efficiency refining agent for refining. When impurities float to the surface of the mixed aluminum melt, the slag is removed. Then, the slag is filtered after standing for 15-20 minutes. Finally, the aluminum liquid is poured out of the furnace to complete the entire use process.

8. The use of a high-efficiency refining agent according to claim 7 in the production of high-performance aluminum alloy materials, characterized in that: The addition amount of the high-efficiency refining agent is 0.5-2% of the mass of the mixed aluminum liquid; the ratio of the aluminum liquid melted and pretreated from scrap aluminum to the aluminum raw material is 0-0.3:

1.

9. The use of a high-efficiency refining agent according to claim 7 in the production of high-performance aluminum alloy materials, characterized in that: The refining gas is argon or nitrogen.

10. An aluminum alloy prepared by using the high-efficiency refining agent as described in any one of claims 7 to 9 in the production of high-performance aluminum alloy materials.

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