Recycling method of aluminum product

Abstract

The invention relates to the technical field of aluminum-based solid waste recycling, in particular to a recycling method of an aluminum product. The recycling method of the aluminum product comprises the following steps that after the aluminum product is crushed, aluminum product fragments are prepared; a plasma jet method is adopted for conducting surface cleaning on the aluminum product fragments, and a first intermediate is prepared; sequentially carrying out high-temperature paint removal and pressing treatment on the first intermediate to prepare a pressed intermediate; and the pressed intermediate is sequentially subjected to smelting and refining treatment, and the aluminum-based melt is prepared. According to the recycling method provided by the invention, the content of impurities and slag inclusion in the aluminum-based melt can be reduced, so that the aluminum-based melt can be used in a preserved or upgraded manner, and the recycling method has the advantages of greenness and recyclability.

Description

Technical Field

[0001] This application relates to the field of aluminum-based solid waste recycling technology, and in particular to a method for recycling aluminum products. Background Technology

[0002] Aluminum cans are widely used as lightweight, aesthetically pleasing, and portable packaging materials. With the continuous growth in aluminum can consumption, the amount of waste aluminum cans generated is also gradually increasing. As a typical aluminum product, its recycling has become crucial for resource circulation.

[0003] Currently, in the recycling of aluminum products, due to inadequate recycling methods, the recycled scrap aluminum alloy melt often contains various impurities, resulting in inclusions and excessive hydrogen content. This makes it difficult to accurately adjust the composition of the recycled melt to the original alloy grade (such as the 3104 aluminum alloy originally used in beverage cans), failing to meet the stringent material performance requirements of high value-added products. Ultimately, it can only be downgraded to produce products with lower performance requirements and lower market added value, resulting in the loss of value of aluminum resources. Summary of the Invention

[0004] Based on this, this application provides a method for recycling aluminum products. The recycling method provided by this application can reduce the impurities and inclusions in aluminum-based melt, enabling the aluminum-based melt to be used in a graded or upgraded manner, and has the advantages of being green and recyclable.

[0005] The first aspect of this application provides a method for recycling aluminum products, comprising the following steps:

[0006] The aluminum product is crushed to prepare aluminum product fragments;

[0007] The aluminum product fragments were surface-cleaned using a plasma jet method to prepare a first intermediate.

[0008] The first intermediate was subjected to paint removal and pressing processes in sequence to prepare a pressed intermediate.

[0009] The pressed intermediate is subjected to smelting and refining processes in sequence to prepare an aluminum-based melt.

[0010] In some embodiments, the process parameters of the plasma jet method include: a frequency of 20kHz to 40kHz, a plasma output power of 400W to 600W, an air flow rate of 2slm to 10slm, and an argon flow rate of 20sccm to 100sccm.

[0011] In some embodiments, the refining process includes adding a refining agent to the smelted material at a mass ratio of 1 ton to (0.1 kg to 0.3 kg), and carrying out the refining process under an inert gas atmosphere and at a temperature of 720°C to 750°C.

[0012] The refining agent comprises the following components by mass fraction: 40%~50% MgCl2, 35%~45% KCl, and 5%~25% KAlF4.

[0013] In some embodiments, the aluminum product is a discarded aluminum can; prior to the step of surface cleaning the product fragments using plasma jet method, the method further includes:

[0014] The aluminum product fragments are screened to remove non-metallic impurities;

[0015] The intermediate after screening is subjected to magnetic separation to remove ferromagnetic metals.

[0016] Eddy current separation is used to separate non-ferrous metals from the intermediate material after magnetic separation to remove iron.

[0017] Laser-induced breakdown spectroscopy is applied to the intermediates after eddy current sorting to separate the can body and lid materials of the waste beverage cans.

[0018] In some embodiments, the preparation steps of the compression intermediate include:

[0019] The first intermediate was subjected to high-temperature thermal devarnishing in a devarnishing furnace at a temperature of 300℃~600℃ for 10min~60min, followed by pressing to prepare a density of 2g / cm³. 3 ~2.4g / cm 3 The aforementioned compression intermediate.

[0020] In some embodiments, the step of melting the pressed intermediate includes: performing initial melting of the pressed intermediate in the outer chamber of a double-chamber furnace at a melt temperature of 680°C to 750°C, and then performing secondary melting in the inner chamber of the double-chamber furnace at a temperature of 750°C to 850°C.

[0021] In some embodiments, the recycling method further includes:

[0022] According to the chemical composition ratio of 3-series, 5-series, or 6-series aluminum alloys, alloying elements are added to the aluminum-based melt to prepare an aluminum alloy melt;

[0023] The aluminum alloy melt is subjected to secondary refining, and after standing, it is cast to prepare aluminum alloy ingots.

[0024] In some embodiments, the secondary refining step includes:

[0025] The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon, and then subjected to secondary refining at a temperature of 710℃~750℃ and a rotation speed of 400rpm~800rpm.

[0026] In the mixture of chlorine and argon, the volume fraction of chlorine is 2% to 10%, and the volume fraction of argon is 90% to 98%.

[0027] In some embodiments, the settling temperature is 710°C to 730°C, and the settling time is 30 min to 120 min.

[0028] In some embodiments, after the settling step and before the casting step, the process further includes:

[0029] The melt after standing is degassed using a mixed gas at a temperature of 690℃~730℃;

[0030] In the mixed gas, the volume fraction of chlorine is 0.15%~0.8%, and the volume fraction of argon is 99.2%~99.85%.

[0031] The beneficial effects of the aluminum recycling method provided in this application include at least the following:

[0032] The recycling method provided in this application first crushes aluminum products into fragments, increasing the contact area for subsequent processing. Then, a plasma jet method is used to clean the surface of the aluminum product fragments, effectively removing oil and surface impurities to obtain a high-cleanliness first intermediate. Next, a high-temperature paint removal process decomposes the organic coating on the surface of the aluminum product fragments, preventing the generation of carbonaceous inclusions and harmful gases during smelting. Pressing reduces waste voids and minimizes gas entrainment during smelting. Smelting combined with refining further removes residual inclusions and hydrogen. Therefore, the recycling method provided in this application, through the synergy of the above steps, effectively reduces the content of non-metallic and organic impurities in the aluminum-based melt, improves the stability and uniformity of the melt composition, and allows the recycled aluminum-based melt to be adjusted to the composition standard of the original alloy grade, meeting the performance requirements of high-value-added products. This achieves the preservation or even upgrading of waste aluminum products, demonstrating the advantages of green recycling. Attached Figure Description

[0033] Figure 1 This is one of the flowcharts illustrating an example of a method for recycling aluminum products provided in this application;

[0034] Figure 2 This is the second flowchart illustrating an example of a method for recycling aluminum products provided in this application.

[0035] Figure 3 Typical inclusion morphology of the aluminum alloy ingot prepared in Example 1 of this application;

[0036] Figure 4 This is a typical slag inclusion morphology diagram of the aluminum alloy ingot prepared in Example 2 of this application;

[0037] Figure 5 Typical inclusion morphology of the aluminum alloy ingot prepared in Example 3 of this application;

[0038] Figure 6 Typical inclusion morphology of aluminum alloy ingot prepared in Comparative Example 1 of this application;

[0039] Figure 7 Typical inclusion morphology of aluminum alloy ingot prepared in Comparative Example 2 of this application;

[0040] Figure 8 This is a typical inclusion morphology diagram of the aluminum alloy ingot prepared in Comparative Example 3 of this application. Detailed Implementation

[0041] The following detailed description of the aluminum recycling method of this application, with reference to specific embodiments, provides a more complete and clear explanation. This application can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and complete understanding of the disclosure of this application.

[0042] In this application, the terms "first" and "second" are used for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Therefore, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0043] When a numerical range is disclosed herein, the range is considered continuous and includes the minimum and maximum values ​​of the range, as well as every value between the minimum and maximum values. Furthermore, when the range refers to integers, it includes every integer between the minimum and maximum values ​​of the range. Additionally, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges to which they are incorporated.

[0044] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. The terminology used herein in the specification of this application is for the purpose of describing particular embodiments only and is not intended to be limiting of the application. Unless otherwise stated or in case of conflict, the terms or phrases used herein have the following meanings:

[0045] In this application, the terms "multiple", "various", "multiple times", "multi-dimensional", etc., unless otherwise specified, refer to a quantity greater than or equal to 2. For example, "one or more" means one or more or more.

[0046] In this application, the terms "first aspect," "second aspect," "third aspect," and "fourth aspect," etc., are used for descriptive purposes only and should not be construed as indicating or implying relative importance or quantity, nor should they be construed as implicitly indicating the importance or quantity of the indicated technical features. Moreover, "first," "second," "third," and "fourth," etc., serve only a non-exhaustive enumeration purpose and should be understood not to constitute a closed limitation on quantity.

[0047] In this application, the technical features described in an open-ended manner include both closed technical solutions consisting of the listed features and open technical solutions that include the listed features.

[0048] In this application, the terms "combinations thereof", "any combination thereof", and "any combination thereof" include all suitable combinations of any two or more of the listed items.

[0049] In this application, the term "suitable" as used in phrases such as "suitable combination," "suitable method," and "any suitable method" refers to the ability to implement the technical solution of this application, solve the technical problem of this application, and achieve the expected technical effect of this application.

[0050] In this application, terms such as "preferred," "better," "more suitable," and "ideal" are used only to describe implementation methods or embodiments with better effects, and should be understood not to constitute a limitation on the scope of protection of this application.

[0051] In this application, terms such as "further," "even further," and "particularly" are used for descriptive purposes to indicate differences in content, but should not be construed as limiting the scope of protection of this application.

[0052] In this application, the terms "optionally," "optionally," and "optional" refer to options that are optional, meaning they can be selected from either "with" or "without." If multiple "optional" options appear in a technical solution, unless otherwise specified and there are no contradictions or mutual constraints, each "optional" option is independent.

[0053] In this application, numerical intervals (i.e., numerical ranges) are involved. Unless otherwise specified, the selected numerical distributions within the aforementioned numerical intervals are considered continuous and include the two endpoints (i.e., the minimum and maximum values) of the numerical range, as well as every value between these two endpoints. Unless otherwise specified, when a numerical interval refers only to integers within that interval, it includes the two endpoint integers of the numerical range, as well as every integer between the two endpoints. In this document, this is equivalent to directly listing every integer. For example, if t is an integer selected from 1 to 10, it means that t is any integer selected from the group of integers consisting of 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10. Furthermore, when multiple ranges are provided to describe features or characteristics, these ranges can be merged. In other words, unless otherwise specified, the ranges disclosed herein should be understood to include any and all subranges to which they are included.

[0054] Unless otherwise specified, the temperature parameters in this application are permitted to be either constant-temperature treatment or variations within a certain temperature range. It should be understood that the constant-temperature treatment allows temperature fluctuations within the precision range of the instrument control, such as ±5℃, ±4℃, ±3℃, ±2℃, or ±1℃.

[0055] In this application, percentage content refers to mass percentage for solid-liquid mixtures and solid-phase mixtures, and volume percentage for liquid-phase mixtures, unless otherwise specified.

[0056] In this application, unless otherwise specified, percentage concentrations refer to final concentrations. The final concentration refers to the percentage of the added component in the system after its addition.

[0057] Currently, the recycling of waste aluminum cans mainly involves processing them into low-value-added products such as AD12 cast aluminum alloys, industrial profiles, and door and window materials. This is primarily because current aluminum recycling methods result in mixed waste materials, with the recycled melt containing large amounts of oil, plastics, cardboard, iron, and other non-ferrous metals. This complex melt composition leads to inclusions and excessive hydrogen content, making it difficult to adjust the alloy composition.

[0058] Based on this, see Figure 1 and Figure 2 The first aspect of this application provides a method for recycling aluminum products, comprising the following steps:

[0059] S10: After crushing aluminum products, aluminum product fragments are prepared.

[0060] S20: The surface of aluminum product fragments is cleaned using plasma jet method to prepare the first intermediate.

[0061] S30: The first intermediate is subjected to paint removal and pressing processes in sequence to prepare a pressed intermediate.

[0062] S40: The pressed intermediate is successively smelted and refined to prepare aluminum-based melt.

[0063] The recycling method provided in this application first crushes aluminum products into fragments, increasing the contact area for subsequent processing. Then, a plasma jet method is used to clean the surface of the aluminum product fragments, effectively removing oil and surface impurities to obtain a high-cleanliness first intermediate. Next, a high-temperature paint removal process decomposes the organic coating on the surface of the aluminum product fragments, preventing the generation of carbonaceous inclusions and harmful gases during smelting. Pressing reduces waste voids and minimizes gas entrainment during smelting. Smelting combined with refining further removes residual inclusions and hydrogen. Therefore, the recycling method provided in this application, through the synergy of the above steps, effectively reduces the content of non-metallic and organic impurities in the aluminum-based melt, improves the stability and uniformity of the melt composition, and allows the recycled aluminum-based melt to be adjusted to the composition standard of the original alloy grade, meeting the performance requirements of high-value-added products. This achieves the preservation or even upgrading of waste aluminum products, demonstrating the advantages of green recycling.

[0064] Furthermore, testing revealed that the Na and Ca content in the aluminum-based melt obtained using the above recycling method was independently ≤5 ppm. As a further example, the inclusion content N in the aluminum-based melt from step S40... 20 ≤12kJ / kgAl. “N 20 "≤12kJ / kgAl" means that the number of inclusion particles larger than 20μm, as determined by nitrogen adsorption, is ≤12,000 per kilogram of aluminum-based melt. In other examples, the aluminum-based melt in step S40, after offline slag analysis using PODFA, has a slag content ≤0.1mm. 2 / kg. "PODFA offline" stands for "Portable On-line Dilution and Filtration Analysis," a commonly used offline detection technique for inclusions in molten metal. "After PODFA offline slag analysis, the slag content is ≤0.1mm." 2 " / kg" indicates that, as determined by the PODFA method, the total projected area of ​​all inclusion particles in each kilogram of aluminum-based melt is ≤0.1 mm². 2 / kg. In some other examples, the hydrogen content in the aluminum-based melt is ≤0.12mL / 100gAl. The above tests on the aluminum-based melt in step S40 all demonstrate that the aluminum-based melt obtained by the recycling method of this application has low trace element content and low inclusion content, and has high purity, which is conducive to the maintenance or upgrading of the recycled melt.

[0065] In some examples, in step S10, the size of the broken aluminum product is 30nm to 100nm. In this application, "size" refers to the maximum linear measurement value in the length, width, or height direction of an object. For example, the size of the broken aluminum product includes, but is not limited to, 30nm, 35nm, 40nm, 45nm, 50nm, 70nm, 80nm, 90nm, or 100nm, or any two of the above values ​​as endpoints. A broken aluminum product with a size within the above range has the advantages of a large specific surface area, which facilitates impurity removal and composition homogenization during subsequent cleaning, smelting, or refining processes.

[0066] In some of these examples, the aluminum products are discarded aluminum cans. Prior to the step of surface cleaning the aluminum product fragments using plasma jet cleaning, the process also includes:

[0067] S11: Screening of aluminum product fragments to remove non-metallic impurities.

[0068] S12: Magnetic separation is performed on the intermediate after screening to remove ferromagnetic metals.

[0069] S13: Eddy current separation is performed on the intermediate body after magnetic separation to remove non-ferrous metals.

[0070] S14: Laser-induced breakdown spectroscopy is applied to the intermediates after eddy current separation to screen the can body and lid materials of waste beverage cans.

[0071] In step S11, the aluminum product fragments are screened to remove lightweight or fine non-metallic impurities such as sand, waste plastic, and waste paper. Further examples include, but are not limited to, vibration and air separation.

[0072] In step S12, the intermediate material after screening is subjected to magnetic separation to remove iron. This avoids problems such as decreased mechanical properties of the ingot due to residual ferromagnetic metals as impurities, ensuring the quality stability of the aluminum-based melt and subsequent recycled aluminum products. The device used for magnetic separation in this step includes, but is not limited to, a magnetic separator.

[0073] In step S13, eddy current separation is performed on the intermediate material after magnetic separation to remove non-ferrous metals such as copper, zinc, and lead. This further reduces the impurity content of the aluminum-based melt, improves the purity of recycled aluminum, reduces the risk of ingot corrosion and performance fluctuations, and ensures product quality. The setup for eddy current separation in this step includes, but is not limited to, eddy current separation equipment.

[0074] Currently, most aluminum cans are two-piece cans. The can bottom and the can body constitute the can body material, which is produced from 3104 aluminum alloy, while the can lid is made from 5182 aluminum alloy. The composition of the can body material and the can lid material differs significantly. For example, 3104 aluminum alloy is an aluminum-magnesium-manganese alloy, with a magnesium content of 0.8%-1.3% and a manganese content of 0.8%-1.4%. In contrast, 5182 aluminum alloy is an aluminum-magnesium alloy, with a higher magnesium content of 4.0%-5.0% and a manganese content of 0.20%-0.50%. Therefore, not classifying the can bottom and the can body would increase the difficulty of adjusting the composition. Based on this, this application uses step S14 to classify the can bottom and the can body of the aluminum can. Understandably, the steps before (such as crushing) and after (such as plasma jetting) of the waste aluminum can can body material and can lid material are the same, except that different aluminum-based melts are prepared separately.

[0075] Laser-induced breakdown spectroscopy (LIBS) is a method for analyzing the composition and concentration of substances based on the emission spectra generated by the interaction of laser light with matter. This technique uses a high-energy laser pulse focused on the sample surface to induce plasma generation. Then, a spectrometer and detector analyze the photons emitted by the plasma at specific wavelengths to determine the sample's composition and content. LIBS can analyze solid, liquid, and gaseous samples. Almost all elements emit characteristic spectral lines when excited to form plasma, thus LIBS can analyze most elements. Therefore, by analyzing the differences in chemical composition between the body and lid materials of waste aluminum cans, it can effectively separate the can and lid materials.

[0076] Furthermore, in step S14, the step of performing laser-induced breakdown spectroscopy on the intermediate material after eddy current separation to screen the can body and lid material of waste beverage cans also includes: AI recognition-assisted screening.

[0077] Tests revealed that after step S14, the screening accuracy of waste aluminum can body and lid materials was >98%. Furthermore, the screening accuracy of waste aluminum can body and lid materials was 98.5%~99.8%.

[0078] In some examples, in step S20, the process parameters of the plasma jet method include: frequency of 20kHz~40kHz, plasma output power of 400W~600W, air flow rate of 2slm~10slm, and argon flow rate of 20sccm~100sccm.

[0079] For example, the frequency of the plasma jet method includes, but is not limited to, 20 kHz, 22 kHz, 25 kHz, 28 kHz, 30 kHz, 32 kHz, 35 kHz, 38 kHz, or 40 kHz, or any two of the above values ​​as endpoints. The plasma output power includes, but is not limited to, 400 W, 420 W, 450 W, 480 W, 500 W, 520 W, 550 W, 580 W, or 600 W, or any two of the above values ​​as endpoints. In the plasma jet method, the air flow rate includes, but is not limited to, 2 slm, 4 slm, 6 slm, 8 slm, or 10 slm, or any two of the above values ​​as endpoints. The argon flow rate includes, but is not limited to, 20 sccm, 30 sccm, 40 sccm, 50 sccm, 60 sccm, 70 sccm, 80 sccm, 90 sccm, or 100 sccm, or any two of the above values ​​as endpoints. In some of these examples, the plasma jet method is performed at room temperature.

[0080] Furthermore, in step S20, the process parameters for the plasma jet method also include: a cleaning time of 20s to 90s. The cleaning time includes, but is not limited to, 20s, 40s, 50s, 60s, 70s, 80s, or 90s.

[0081] This application finds that the plasma jet process using the above parameters has a high surface cleaning rate for aluminum product fragments, and can effectively remove surface oil, oxide scale and micro dust impurities. Therefore, it can reduce the introduction of inclusions and impurity elements in the recycled aluminum-based melt, improve the purity of the aluminum-based melt, and lay the foundation for subsequent grade maintenance or upgrading.

[0082] In some of these examples, step S30, the preparation step of the compressed intermediate, includes:

[0083] The first intermediate was subjected to high-temperature thermal devarnishing in a devarnishing furnace at a temperature of 300℃~600℃ for 10min~60min; subsequently, it was pressed to prepare a density of 2g / cm³. 3 ~2.4g / cm 3 The suppression intermediate.

[0084] For example, the temperature for high-temperature heat paint stripping includes, but is not limited to, 300°C, 320°C, 350°C, 380°C, 400°C, 420°C, 450°C, 470°C, 490°C, 500°C, 520°C, 550°C, 580°C, or 600°C.

[0085] Since aluminum can fragments often have paint and other organic matter adhering to their surface, high-temperature paint removal from the surface of the first intermediate can remove these impurities. By controlling the process parameters of paint removal, dioxin emissions can be made within acceptable limits. Simultaneously, briquetting increases density, facilitating subsequent smelting and thus reducing pollution and energy consumption in the aluminum-based melt. Furthermore, this high-temperature paint removal can achieve a dioxin emission concentration of <0.5 ng TEQ / m³. 3 .

[0086] Furthermore, the apparatus for high-temperature paint removal using the heating medium for paint stripping includes, but is not limited to, a paint stripping kiln; and the exhaust port of the paint stripping kiln is preferably equipped with a plasma auxiliary melting device, which helps to further reduce dioxin emissions.

[0087] In some of these examples, the density of the compressed intermediate includes, but is not limited to, 2 g / cm³. 3 2.1g / cm 3 2.2g / cm 3 2.3g / cm 3 Or 2.4g / cm 3 .

[0088] In some examples, step S40, the process of melting the pressed intermediate, includes: initial melting of the pressed intermediate in the outer chamber of a dual-chamber furnace at a melt temperature of 680°C to 750°C, followed by secondary melting in the inner chamber of the dual-chamber furnace at a temperature of 750°C to 850°C. Further, the initial melting temperature includes, but is not limited to, 680°C, 700°C, 720°C, or 750°C, or any two of these values ​​as endpoints. The secondary melting temperature includes, but is not limited to, 680°C, 690°C, 700°C, 720°C, or 750°C. Staged initial melting at 680°C to 750°C and secondary melting at 750°C to 850°C for the pressed intermediate achieves stable melting and improves melt uniformity and purity.

[0089] In some examples, step S40, the refining process includes: adding a refining agent to the smelted material at a mass ratio of 1 ton to (0.1 kg to 0.3 kg), and carrying out the refining process under an inert gas atmosphere and at a temperature of 720°C to 750°C.

[0090] For example, the inert gas atmosphere in the refining step includes, but is not limited to, argon. Further, the refining time is ≥30 min. The refining time is 30 min to 120 min. The mass ratio of the refining agent added to the smelted material includes, but is not limited to, 1 ton: 0.1 kg, 1 ton: 0.2 kg, or 1 ton: 0.3 kg.

[0091] The refining agent comprises the following components by mass fraction: 40%–50% MgCl2, 35%–45% KCl, and 5%–25% KAlF4. This application selects the above-mentioned refining agent, which can effectively reduce the melting temperature of the refining agent. Furthermore, the introduction of KAlF4 can alter the surface tension among the refining agent, the molten aluminum, and the oxide inclusions, thereby enhancing the adsorption of oxide inclusions by the refining agent and improving the refining effect.

[0092] For example, the mass fraction of MgCl2 includes, but is not limited to, 40%, 42%, 45%, 48%, or 50%. The mass fraction of KCl includes, but is not limited to, 35%, 38%, 40%, 42%, or 45%. The mass fraction of KAlF4 includes, but is not limited to, 5%, 10%, 15%, 20%, or 25%.

[0093] Furthermore, the refining agent in this application does not include KBF4 and CaF2. This application uses aluminum-based melt for the recycling of high-Mg-content 3-series, 5-series, and 6-series aluminum alloys. This application has found that the CaF2 component in the refining agent reacts with Mg to form Ca, and Ca, as an impurity element, significantly reduces the formability of the ingot. Therefore, the refining agent in this application does not include CaF2. In addition, this application has found that although the B element in the KBF4 component of the refining agent can combine with Ti in the recycled aluminum alloy to form TiB2 particles, the TiB2 particles are easily deactivated in the subsequent melting and ingot preparation steps, resulting in clustering and segregation, which cannot effectively refine the grains.

[0094] In some of these examples, the recycling methods also include:

[0095] S50: An aluminum alloy melt is prepared by adding alloying elements to an aluminum-based melt according to the chemical composition ratio of 3-series, 5-series, or 6-series aluminum alloys.

[0096] S60: The aluminum alloy melt is refined twice, allowed to stand, and then cast to prepare aluminum alloy ingots.

[0097] Understandably, in step S50, the chemical composition of the aluminum-based melt can be analyzed, and raw materials such as electrolytic aluminum liquid, pure aluminum ingots, or intermediate alloys can be added to adjust the content of alloying elements such as Si, Fe, Cu, Mn, Mg, Cr, Zn, or Ti in the aluminum-based melt, so that the chemical composition and content of the aluminum alloy melt meet the requirements of 3-series, 5-series, or 6-series aluminum alloys for beverage can body materials, can lid materials, or automotive aluminum alloy plates, strips, and profiles.

[0098] In some examples, in step S50, the mass fraction of aluminum-based melt in the aluminum alloy melt is 60% to 90%. Because the recycling method provided in this application results in a low impurity content in the aluminum-based melt, it accounts for a relatively high proportion of the mass of the aluminum alloy melt.

[0099] In some of these examples, step S60, the secondary refining step includes:

[0100] The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon, and then subjected to secondary refining at a temperature of 710℃~750℃ and a rotation speed of 400rpm~800rpm.

[0101] For example, the temperature for secondary refining includes, but is not limited to, 710°C, 715°C, 720°C, 725°C, 730°C, 740°C, or 750°C. The speed for secondary refining includes, but is not limited to, 400 rpm, 500 rpm, 600 rpm, 700 rpm, or 800 rpm.

[0102] In some examples, in step S60, the volume fraction of chlorine in the mixed gas containing chlorine and argon is 2% to 10%, and the volume fraction of argon is 90% to 98%. The volume fraction of chlorine includes, but is not limited to, 2%, 3%, 5%, 8%, or 10%. The volume fraction of argon includes, but is not limited to, 90%, 92%, 95%, 96%, or 98%. Secondary refining of the aluminum alloy melt using a mixed gas containing chlorine and argon at 710℃ to 750℃ and 400rpm to 800rpm can efficiently remove gases and inclusions, improve melt purity, and ensure the density and mechanical property stability of the aluminum alloy ingot.

[0103] In some examples, in step S60, the settling temperature is 710℃~730℃, and the settling time is 30min~120min. Settling the aluminum alloy melt allows residual inclusions and bubbles to rise and separate fully, further improving the melt's uniformity and purity, and ensuring ingot quality. For example, the settling temperature includes, but is not limited to, 710℃, 715℃, 720℃, 725℃, or 730℃. The settling time includes, but is not limited to, 30min, 40min, 50min, 60min, 70min, 80min, 90min, 100min, 110min, or 120min.

[0104] In some examples, step S60, following the settling step and the casting process, also includes:

[0105] The melt after standing is degassed using a mixed gas at a temperature of 690℃~730℃.

[0106] In this mixture, the volume fraction of chlorine is 0.15%~0.8%, and the volume fraction of argon is 99.2%~99.85%. Degassing the settled melt using this mixture at 690℃~730℃ can efficiently remove residual gases, reduce ingot porosity defects, and improve material density and mechanical properties. For example, the volume fraction of chlorine in the mixture may include, but is not limited to, 0.15%, 0.3%, 0.5%, or 0.8%. The volume fraction of argon may include, but is not limited to, 99.2%, 99.5%, 99.7%, or 99.85%. The degassing temperature may include, but is not limited to, 690℃, 700℃, 710℃, 720℃, or 730℃.

[0107] The following detailed embodiments illustrate this application in more detail. It should also be understood that the following embodiments are for further explanation only and should not be construed as limiting the scope of protection of this application. Any non-essential improvements and adjustments made by those skilled in the art based on the above description of this application fall within the scope of protection of this application. The specific process parameters, etc., in the following embodiments are merely examples within a suitable range; that is, those skilled in the art can make appropriate selections within the range based on the description herein, and are not necessarily limited to the specific values ​​in the embodiments below.

[0108] Example 1

[0109] Example 1 provides a method for recycling aluminum products, comprising the following steps:

[0110] (1) Crushing: Take waste aluminum cans, crush them, and prepare aluminum product fragments with a size of 30nm~100nm.

[0111] (2) Screening-Magnetic separation for iron removal-Eddy current separation-Laser-induced breakdown spectroscopy: The aluminum product fragments are screened by vibration and air separation to remove light or small non-metallic impurities such as sand, waste plastics, and waste paper; the intermediates after removing non-metallic impurities are subjected to magnetic separation to remove ferromagnetic metals; the intermediates after removing ferromagnetic metals are subjected to eddy current separation to remove non-ferrous metals such as copper, zinc, and lead; the intermediates after removing non-ferrous metals are subjected to laser-induced breakdown spectroscopy and AI recognition to screen the can body and can lid materials of waste beverage cans.

[0112] (3) Plasma cleaning: The aluminum product fragments of the tank material after screening are subjected to 30s plasma jet surface cleaning to remove surface oil, coating and other organic matter. The process parameters of plasma jet method include: frequency of 25kHz, plasma output power of 450W, air flow rate of 5slm, argon flow rate of 60sccm, and cleaning temperature of 30℃ to prepare the first intermediate.

[0113] (4) High-temperature paint removal: The first intermediate is subjected to high-temperature thermal paint removal in a paint removal kiln at 400℃ for 20 minutes. During the paint removal process, the intermediate rotates, and the first intermediate collides and rubs against each other at high temperature to remove surface oil and paint coating. The exhaust port of the paint removal kiln is equipped with a plasma-assisted melting device to treat surface organic matter such as the first intermediate, achieving a dioxin emission concentration of <0.5ng TEQ / m³. 3 .

[0114] (5) Pressing treatment: The intermediate after high-temperature paint removal is pressed to prepare a density of 2.2 g / cm³. 3 The suppression intermediate.

[0115] (6) Melting: The pressed intermediate is fed into the aluminum molten metal in the outer chamber of the double-chamber furnace. The initial melting takes place in the outer chamber at a temperature of 710°C. The bottom of the outer chamber molten metal is equipped with an electromagnetic stirring device. The pressed intermediate enters the molten vortex formed by the electromagnetic stirring device, avoiding prolonged contact with flames or air and improving the recovery rate. The secondary melting takes place in the inner chamber at a temperature of 820°C. Gas heating is used for heating and heat preservation. The outer and inner chambers are circulated by a ceramic pump, and the high-temperature molten metal in the inner chamber ensures the temperature of the molten metal in the outer chamber.

[0116] (7) Refining: Add refining agent to the smelted material at a mass ratio of 1 ton: 0.2 kg, and perform refining treatment for 50 min under an argon atmosphere and a temperature of 740°C to obtain aluminum-based melt. The refining agent includes the following components by mass fraction: 45% MgCl2, 40% KCl, and 15% KAlF4.

[0117] (8) Adding alloying elements: After slag removal, the aluminum-based melt is subjected to online melt composition detection using laser-induced breakdown spectroscopy technology + machine learning-based alloy design system: automatically matching scrap type and addition ratio and intermediate alloy, and according to the content of Si, Fe, Mn, Cu, Mg, Zn and Ti elements in the melt, a certain amount of electrolytic aluminum water or pure aluminum ingot or intermediate alloy is added to make the melt composition meet the composition requirements of 3104 alloy in GB / T3190-2020, and aluminum alloy melt is prepared.

[0118] (9) Secondary refining: The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon and the secondary refining is carried out for 30 minutes at a temperature of 730°C and a rotation speed of 600 rpm; the volume fraction of chlorine in the mixed gas containing chlorine and argon is 4% and the volume fraction of argon is 96%.

[0119] (10) Standing: The aluminum alloy melt after secondary refining is placed at a standing temperature of 730℃ for 40 minutes.

[0120] (11) Casting: The melt after standing is degassed online at a temperature of 710℃ using a mixed gas. The volume fraction of chlorine in the mixed gas is 0.3% and the volume fraction of argon is 99.7%. After using a two-stage plate filter (40ppi+60ppi) + tube test filter, the aluminum alloy ingot is cast to meet the composition requirements of 3104 alloy in GB / T3190-2020.

[0121] The chemical composition of the aluminum alloy ingot prepared in Example 1 is compared with that of the standard 3104 alloy, as shown in Table 1. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured; the corresponding test results are shown in Table 2. Typical slag inclusion morphologies of the aluminum alloy ingot prepared in Example 1 are shown in Table 2. Figure 3 As shown.

[0122] Example 2

[0123] The method for recycling aluminum products provided in Example 2 is basically the same as that in Example 1. The main difference is that steps (3) and (8) in Example 2 are different from those in Example 1. In step (3) of Example 2, plasma cleaning is performed on the surface of the screened aluminum can lid material fragments by plasma jet cleaning for 30 seconds. At the same time, the subsequent treatment is performed on the aluminum can lid material fragments.

[0124] Step (8) of Example 2 is as follows:

[0125] (8) Adding alloying elements: After slag removal, the aluminum-based melt is subjected to online melt composition detection using laser-induced breakdown spectroscopy technology + machine learning-based alloy design system: automatically matching scrap type and addition ratio and intermediate alloy, and according to the content of Si, Fe, Mn, Cu, Mg, Zn and Ti elements in the melt, a certain amount of electrolytic aluminum water or pure aluminum ingot or intermediate alloy is added to make the melt composition meet the composition requirements of 5182 alloy in GB / T3190-2020, and aluminum alloy melt is prepared.

[0126] The chemical composition of the aluminum alloy ingot prepared in Example 2 is compared with that of standard 5182 alloy in Table 1. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured. The corresponding test results are shown in Table 2. Typical slag inclusion morphologies of the aluminum alloy ingot prepared in Example 2 are shown in Table 2. Figure 4 As shown.

[0127] Example 3

[0128] Example 3 provides a method for recycling aluminum products, including the following steps:

[0129] (1) Crushing: Take waste aluminum cans, crush them, and prepare aluminum product fragments with a size of 30nm~100nm.

[0130] (2) Screening-Magnetic separation for iron removal-Eddy current separation-Laser-induced breakdown spectroscopy: The aluminum product fragments are screened by vibration and air separation to remove light or small non-metallic impurities such as sand, waste plastics, and waste paper; the intermediates after removing non-metallic impurities are subjected to magnetic separation to remove ferromagnetic metals; the intermediates after removing ferromagnetic metals are subjected to eddy current separation to remove non-ferrous metals such as copper, zinc, and lead; the intermediates after removing non-ferrous metals are subjected to laser-induced breakdown spectroscopy and AI recognition to screen the can body and can lid materials of waste beverage cans.

[0131] (3) Plasma cleaning: The sieved aluminum fragments of the can body and the sieved aluminum fragments of the can lid are subjected to 30s plasma jet surface cleaning to remove surface oil, coatings and other organic matter. The process parameters of the plasma jet method include: frequency of 25kHz, plasma output power of 450W, air flow rate of 5slm, argon flow rate of 60sccm, and cleaning temperature of 30℃, to prepare the first intermediate.

[0132] (4) High-temperature paint removal: The first intermediate is subjected to high-temperature thermal paint removal in a paint removal kiln at 400℃ for 20 minutes. During the paint removal process, the intermediate rotates, and the first intermediate collides and rubs against each other at high temperature to remove surface oil and paint coating. The exhaust port of the paint removal kiln is equipped with a plasma-assisted melting device to treat surface organic matter such as the first intermediate, achieving a dioxin emission concentration of <0.5ng TEQ / m³. 3 .

[0133] (5) Pressing treatment: The intermediate after high-temperature paint removal is pressed to prepare a density of 2.2 g / cm³. 3 The suppression intermediate.

[0134] (6) Melting: The pressed intermediate is fed into the aluminum molten metal in the outer chamber of the double-chamber furnace. The initial melting takes place in the outer chamber at a temperature of 710°C. The bottom of the outer chamber molten metal is equipped with an electromagnetic stirring device. The pressed intermediate enters the molten vortex formed by the electromagnetic stirring device, avoiding prolonged contact with flames or air and improving the recovery rate. The secondary melting takes place in the inner chamber at a temperature of 820°C. Gas heating is used for heating and heat preservation. The outer and inner chambers are circulated by a ceramic pump, and the high-temperature molten metal in the inner chamber ensures the temperature of the molten metal in the outer chamber.

[0135] (7) Refining: Add refining agent to the smelted material at a mass ratio of 1 ton: 0.2 kg, and perform refining treatment for 50 min under an argon atmosphere and a temperature of 740°C to obtain aluminum-based melt. The refining agent includes the following components by mass fraction: 45% MgCl2, 40% KCl, and 15% KAlF4.

[0136] (8) Adding alloying elements: After slag removal, the aluminum-based melt is subjected to online melt composition detection using laser-induced breakdown spectroscopy technology + machine learning-based alloy design system: automatically matching scrap type and addition ratio and intermediate alloy, and according to the content of Si, Fe, Mn, Cu, Mg, Zn and Ti elements in the melt, a certain amount of electrolytic aluminum water or pure aluminum ingot or intermediate alloy is added to make the melt composition meet the composition requirements of 3104 alloy in GB / T3190-2020, and aluminum alloy melt is prepared.

[0137] (9) Secondary refining: The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon and the secondary refining is carried out for 30 minutes at a temperature of 730°C and a rotation speed of 600 rpm; the volume fraction of chlorine in the mixed gas containing chlorine and argon is 4% and the volume fraction of argon is 96%.

[0138] (10) Standing: The aluminum alloy melt after secondary refining is placed at a standing temperature of 730℃ for 40 minutes.

[0139] (11) Casting: The melt after standing is degassed online at a temperature of 710℃ using a mixed gas. The volume fraction of chlorine in the mixed gas is 0.3% and the volume fraction of argon is 99.7%. After using a two-stage plate filter (40ppi+60ppi) + tube test filter, the aluminum alloy ingot is cast to meet the composition requirements of 6082 alloy in GB / T3190-2020.

[0140] The chemical composition of the aluminum alloy ingot prepared in Example 3 is compared with that of standard 6082 alloy in Table 1. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured. The corresponding test results are shown in Table 2. Typical slag inclusion morphologies of the aluminum alloy ingot prepared in Example 3 are shown in Table 2. Figure 5 As shown.

[0141] Comparative Example 1

[0142] The recycling method for aluminum products provided in Comparative Example 1 is basically the same as that in Example 1. The main difference is that Comparative Example 1 does not include steps (1) to (5), and directly melts down the waste aluminum cans.

[0143] Table 1 shows a comparison of the chemical composition of the aluminum alloy ingot prepared in Comparative Example 1 with that of the standard 3104 alloy. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured; the corresponding test results are shown in Table 2. Typical inclusion morphologies of the aluminum alloy ingot prepared in Comparative Example 1 are shown in Table 2. Figure 6 As shown.

[0144] Comparative Example 2

[0145] (1) Crushing: Take waste aluminum cans, crush them, and prepare aluminum product fragments with a size of 30nm~100nm.

[0146] (2) Screening-Magnetic separation for iron removal-Edge current separation-Laser-induced breakdown spectroscopy: The aluminum product fragments are screened by vibration and air separation to remove light or small non-metallic impurities such as sand, waste plastics, and waste paper; the intermediates after removing non-metallic impurities are subjected to magnetic separation to remove ferromagnetic metals; the intermediates after removing ferromagnetic metals are subjected to eddy current separation to remove non-ferrous metals such as copper, zinc, and lead.

[0147] (3) High-temperature paint removal: The aluminum product fragments are subjected to high-temperature thermal paint removal in a paint removal kiln at a temperature of 400℃ for 20 minutes. During the paint removal process, the aluminum product fragments are rotated and collide and rub against each other at high temperature to remove surface oil and paint coating. The exhaust port of the paint removal kiln is equipped with a plasma auxiliary melting device to treat organic matter on the surface of aluminum product fragments.

[0148] (4) Melting: The high-temperature paint removal intermediate is introduced into the aluminum melt in the outer chamber of the double-chamber furnace. The initial melting takes place in the outer chamber at a temperature of 710°C. The bottom of the melt in the outer chamber is equipped with an electromagnetic stirring device, which presses the intermediate into the melt vortex formed by the electromagnetic stirring device, avoiding prolonged contact with flame or air and improving the recovery rate. The secondary melting takes place in the inner chamber at a temperature of 820°C. Gas heating is used for heating and heat preservation. The melt is circulated between the outer and inner chambers through a ceramic pump. The high-temperature melt in the inner chamber ensures the temperature of the melt in the outer chamber. After melting, an aluminum-based melt is obtained.

[0149] (5) Adding alloying elements: The aluminum-based melt is subjected to online melt composition detection using laser-induced breakdown spectroscopy technology + machine learning-based alloy design system: automatically matching scrap type and addition ratio and intermediate alloy. Based on the content of Si, Fe, Mn, Cu, Mg, Zn and Ti elements in the melt, a certain amount of electrolytic aluminum water or pure aluminum ingot or intermediate alloy is added to make the melt composition meet the composition requirements of 5182 alloy in GB / T3190-2020, and aluminum alloy melt is prepared.

[0150] (6) Secondary refining: The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon and the secondary refining is carried out for 30 minutes at a temperature of 730°C and a rotation speed of 600 rpm; the volume fraction of chlorine in the mixed gas containing chlorine and argon is 4% and the volume fraction of argon is 96%.

[0151] (7) Casting: The melt after secondary refining is degassed online at a temperature of 710℃ using a mixed gas. The volume fraction of chlorine in the mixed gas is 0.3% and the volume fraction of argon is 99.7%. After using a two-stage plate filter (40ppi+60ppi) + tube test filter, the aluminum alloy ingot is cast to meet the composition requirements of 5182 alloy in GB / T3190-2020.

[0152] Table 1 shows a comparison of the chemical composition of the aluminum alloy ingot prepared in Comparative Example 2 with that of standard 5182 alloy. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured; the corresponding test results are shown in Table 2. Typical inclusion morphologies of the aluminum alloy ingot prepared in Comparative Example 2 are shown in Table 2. Figure 7 As shown.

[0153] Comparative Example 3

[0154] (1) Crushing: Take waste aluminum cans, crush them, and prepare aluminum product fragments with a size of 30nm~100nm.

[0155] (2) Screening-Magnetic separation for iron removal-Edge current separation-Laser-induced breakdown spectroscopy: The aluminum product fragments are screened by vibration and air separation to remove light or small non-metallic impurities such as sand, waste plastics, and waste paper; the intermediates after removing non-metallic impurities are subjected to magnetic separation to remove ferromagnetic metals; the intermediates after removing ferromagnetic metals are subjected to eddy current separation to remove non-ferrous metals such as copper, zinc, and lead.

[0156] (3) High-temperature paint removal: The aluminum product fragments are subjected to high-temperature thermal paint removal in a paint removal kiln at a temperature of 400℃ for 20 minutes. During the paint removal process, the aluminum product fragments are rotated and collide and rub against each other at high temperature to remove surface oil and paint coating. The exhaust port of the paint removal kiln is equipped with a plasma auxiliary melting device to treat organic matter on the surface of aluminum product fragments.

[0157] (4) Melting: The intermediate material after high-temperature paint removal is placed into the aluminum melt in the outer chamber of the double-chamber furnace. The initial melting is carried out in the outer chamber at a temperature of 710°C. The bottom of the melt in the outer chamber is equipped with an electromagnetic stirring device. The intermediate material after high-temperature paint removal enters the melt vortex formed by the electromagnetic stirring device, avoiding prolonged contact with flame or air and improving the recovery rate. The secondary melting is carried out in the inner chamber at a melt temperature of 820°C. Gas heating is used for heating and heat preservation. The melt is circulated between the outer and inner chambers through a ceramic pump. The high-temperature melt in the inner chamber ensures the temperature of the melt in the outer chamber.

[0158] (5) Refining: Add refining agent to the smelted material at a mass ratio of 1 ton: 0.2 kg, and perform refining treatment for 50 min under an argon atmosphere and a temperature of 740°C to obtain aluminum-based melt. The refining agent includes the following components by mass fraction: 50% KCl and 50% MgCl2.

[0159] (6) Adding alloying elements: After slag removal, the aluminum-based melt is subjected to online melt composition detection using laser-induced breakdown spectroscopy technology + machine learning-based alloy design system: automatically matching scrap type and addition ratio and intermediate alloy. Based on the content of Si, Fe, Mn, Cu, Mg, Zn and Ti elements in the melt, a certain amount of electrolytic aluminum water or pure aluminum ingot or intermediate alloy is added to make the melt composition meet the composition requirements of 6082 alloy in GB / T3190-2020, and aluminum alloy melt is prepared.

[0160] (7) Secondary refining: The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon and the secondary refining is carried out for 30 minutes at a temperature of 730°C and a rotation speed of 600 rpm; the volume fraction of chlorine in the mixed gas containing chlorine and argon is 4% and the volume fraction of argon is 96%.

[0161] (8) Casting: The melt after secondary refining is degassed online at a temperature of 710℃ using a mixed gas. The volume fraction of chlorine in the mixed gas is 0.3%, and the volume fraction of argon is 99.7%. After using a two-stage plate filter (40ppi+60ppi) + tube test filter, the aluminum alloy ingot is cast to meet the composition requirements of 6082 alloy in GB / T3190-2020.

[0162] The chemical composition of the aluminum alloy ingot prepared in Comparative Example 3 is compared with that of standard 6082 alloy in Table 1. The hydrogen content of the melt after online degassing was measured, and the slag content and alkali metal content of the melt after tubular filtration were measured; the corresponding test results are shown in Table 2. Typical inclusion morphologies of the aluminum alloy ingot prepared in Comparative Example 3 are shown in Table 2. Figure 8 As shown.

[0163] Table 1

[0164]

[0165] Table 2

[0166]

[0167] As shown in the test results in Tables 1 and 2 above, the embodiments of this application, using waste aluminum cans as raw materials, achieve the green, low-carbon, grade preservation or upgrading recycling of waste aluminum cans through specific process steps. Embodiments 1 to 3 use ≥70% recycled waste aluminum cans combined with a certain amount of pure aluminum and intermediate alloys, which can be used to produce high-quality aluminum alloy ingots of 3XXX, 5XXX, and 6XXX grades. These high-quality aluminum alloy ingots can be used for the production of recycled can body materials, can lid materials, or automotive aluminum alloy plates, strips, and profiles. Therefore, the recycling method provided by this application is green, low-carbon, and recyclable, achieving the grade preservation or upgrading of waste aluminum cans, while also having significant economic benefits.

[0168] Comparing Examples 1-3 and Comparative Examples 1-3, it can be seen that, from the perspective of alloy element control, although both the examples and the comparative examples can achieve the requirements of the corresponding alloy grades in the national standard for the main alloy elements such as Si, Fe, Mn, Cr, Mg, Zn, and Ti in the recycled aluminum alloy ingots through alloy element control, the proportion of recycled material added in the comparative examples is significantly lower than that in the examples, and the content of alkali metals such as Na and Ca in the comparative examples is significantly higher than that in the examples. The high content of alkali metals will inevitably lead to a decrease in the alloy processing performance and product performance.

[0169] Furthermore, comparing the hydrogen content and slag content of the comparative examples and the specific examples, it can be seen that the hydrogen content and slag content in the comparative examples are significantly higher than those in the specific examples, as shown in Table 2 and... Figures 3-8 As shown. This will inevitably have a serious impact on processing performance and the performance of the final product, making it impossible to maintain its grade.

[0170] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0171] The embodiments described above are merely illustrative of several implementation methods of this application, intended to facilitate a detailed understanding of the technical solutions of this application, but should not be construed as limiting the scope of protection of the invention patent. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the scope of protection of this application. It should be understood that technical solutions obtained by those skilled in the art based on the technical solutions provided in this application through logical analysis, reasoning, or limited experimentation are all within the scope of protection of the appended claims. Therefore, the scope of protection of this patent application should be determined by the content of the appended claims, and the specification can be used to interpret the content of the claims.

Claims

1. A method for recycling aluminum products, characterized in that, Includes the following steps: The aluminum product is crushed to prepare aluminum product fragments; The aluminum product fragments were surface-cleaned using a plasma jet method to prepare a first intermediate. The first intermediate was subjected to paint removal and pressing processes in sequence to prepare a pressed intermediate. The pressed intermediate is subjected to smelting and refining processes in sequence to prepare an aluminum-based melt.

2. The method for recycling aluminum products according to claim 1, characterized in that, The process parameters for plasma jet method include: frequency of 20kHz~40kHz, plasma output power of 400W~600W, air flow rate of 2slm~10slm, and argon flow rate of 20sccm~100sccm.

3. The method for recycling aluminum products according to claim 1, characterized in that, The refining process includes adding a refining agent to the smelted material at a mass ratio of 1 ton to (0.1 kg to 0.3 kg), and then refining the material under an inert gas atmosphere and at a temperature of 720°C to 750°C. The refining agent comprises the following components by mass fraction: 40%~50% MgCl2, 35%~45% KCl, and 5%~25% KAlF4.

4. The method for recycling aluminum products according to any one of claims 1 to 3, characterized in that, The aluminum product is a discarded aluminum can; Before the step of surface cleaning the aluminum product fragments using plasma jet method, the method further includes: The aluminum product fragments are screened to remove non-metallic impurities; The intermediate after screening is subjected to magnetic separation to remove ferromagnetic metals. Eddy current separation is used to separate non-ferrous metals from the intermediate material after magnetic separation to remove iron. Laser-induced breakdown spectroscopy is applied to the intermediates after eddy current sorting to separate the can body and lid materials of the waste beverage cans.

5. The method for recycling aluminum products according to any one of claims 1 to 3, characterized in that, The preparation steps of the compression intermediate include: The first intermediate was subjected to high-temperature thermal devarnishing in a devarnishing furnace at a temperature of 300℃~600℃ for 10min~60min, followed by pressing to prepare a density of 2g / cm³. 3 ~2.4g / cm 3 The aforementioned compression intermediate.

6. The method for recycling aluminum products according to any one of claims 1 to 3, characterized in that, The step of melting the pressed intermediate includes: first melting the pressed intermediate in the outer chamber of a double-chamber furnace at a melt temperature of 680°C to 750°C, and then second melting in the inner chamber of the double-chamber furnace at a temperature of 750°C to 850°C.

7. The method for recycling aluminum products according to any one of claims 1 to 3, characterized in that, The recycling method further includes: According to the chemical composition ratio of 3-series, 5-series, or 6-series aluminum alloys, alloying elements are added to the aluminum-based melt to prepare an aluminum alloy melt; The aluminum alloy melt is subjected to secondary refining, and after standing, it is cast to prepare aluminum alloy ingots.

8. The method for recycling aluminum products according to claim 7, characterized in that, The secondary refining process includes: The aluminum alloy melt is sprayed with a mixed gas containing chlorine and argon, and then subjected to secondary refining at a temperature of 710℃~750℃ and a rotation speed of 400rpm~800rpm. In the mixture of chlorine and argon, the volume fraction of chlorine is 2% to 10%, and the volume fraction of argon is 90% to 98%.

9. The method for recycling aluminum products according to claim 7, characterized in that, The settling temperature is 710℃~730℃, and the settling time is 30min~120min.

10. The method for recycling aluminum products according to claim 7, characterized in that, After the settling step and before the casting process, it also includes: The melt after standing is degassed using a mixed gas at a temperature of 690℃~730℃; In the mixed gas, the volume fraction of chlorine is 0.15%~0.8%, and the volume fraction of argon is 99.2%~99.85%.

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