A composite purification method and integrated molding process for recycled aluminum alloy melt

Abstract

This invention discloses a composite purification method and integrated forming process for recycled aluminum alloy melt, relating to the field of recycled aluminum alloy processing. The composite purification process involves sequential physical field pretreatment and deep chemical purification. The recycled aluminum melt is pretreated using a magnetic field combined with inert gas blowing, followed by deep chemical purification with a composite refining agent containing rare earth elements, achieving deep impurity and degassing of the melt. The integrated forming process uses the purified melt as raw material to produce aluminum alloy castings through die casting. The die casting process utilizes machine learning to optimize process parameters, and the die casting equipment integrates multiple sets of automated equipment. Simultaneously, a full lifecycle service system based on the Industrial Internet is established. This invention exhibits good process synergy, effectively improving melt purity and casting quality, adapting to the needs of industrial production, and contributing to the high-value utilization of recycled aluminum resources.

Description

Technical Field

[0001] This invention relates to the field of recycled aluminum alloy material processing, and in particular to a method for composite purification of recycled aluminum alloy melt and an integrated forming process. Background Technology

[0002] Against the backdrop of the deep development of the circular economy, recycled aluminum alloys, with their advantages of high resource utilization, low carbon emissions, and low production costs, have become an important alternative to virgin aluminum alloys in the high-end equipment manufacturing field. This is especially true in the production of key castings such as mixers for sixteen-cylinder diesel generator sets, where the demand for high-value applications of recycled aluminum alloys is increasingly urgent. However, the raw materials for recycled aluminum alloys are complex, and the melt is easily mixed with hydrogen, oxide inclusions, and harmful impurities such as V, Ti, Mn, and Cr. This leads to defects such as porosity, looseness, and cracks in recycled aluminum castings, making it difficult for them to meet the stringent service requirements of high-end power equipment castings. This has become a core bottleneck restricting the large-scale application of recycled aluminum alloys in the high-end equipment manufacturing field.

[0003] Currently, the purification of recycled aluminum alloy melts mostly employs single physical or chemical purification methods. While single magnetic field physical treatment can achieve the separation of some inclusions, its degassing efficiency is low and it is difficult to remove fine inclusions. Simple flux refining has limited effect on removing harmful impurities from the melt, and conventional refining agents lack specificity, failing to simultaneously achieve multiple effects of impurity removal, degassing, and melt performance regulation. The simple superposition of physical and chemical purification technologies also suffers from poor process synergy, easily causing secondary contamination of the melt and making it difficult to obtain high-purity recycled aluminum melts. The hydrogen content and impurity content of the melt are difficult to meet the production requirements of high-end castings.

[0004] In the process of forming recycled aluminum alloy castings, existing processes mostly rely on experience-based die-casting parameter settings, lacking dynamic matching with the real-time state of the melt. Furthermore, the die-casting equipment has a low level of intelligence, failing to achieve integrated processing of pouring, unloading, and inspection. This makes it difficult to detect and report internal defects in the castings in a timely manner, resulting in poor casting quality stability. Simultaneously, the existing recycled aluminum alloy production process lacks a full lifecycle management and traceability system. Data from raw material recycling, melt purification, and die-casting are not effectively integrated, hindering digital control of the entire production process and restricting the high-quality, large-scale production of recycled aluminum alloy castings.

[0005] To address the high-performance and high-stability production requirements of recycled aluminum alloy castings for high-end equipment, there is an urgent need to develop a melt composite purification method that integrates physical fields and chemical methods, and to develop a matching intelligent integrated molding process. This would solve the problems of poor purification effect, low level of intelligence in molding process, and insufficient quality control and traceability capabilities of existing technologies, and achieve deep purification of recycled aluminum alloy melts and high-precision, high-performance molding of castings, thereby promoting the industrial application of recycled aluminum alloys in the field of high-end power equipment manufacturing.

[0006] The above background information is provided only to aid in understanding the inventive concept and technical solution of this invention. It does not necessarily belong to the prior art of this patent application. In the absence of clear evidence that the above information was disclosed on the filing date of this patent application, the above background information should not be used to evaluate the novelty and inventiveness of this application. Summary of the Invention

[0007] The main objective of this invention is to propose a composite purification method and integrated molding process for recycled aluminum alloy melt, in order to solve the technical problems of incomplete purification of recycled aluminum alloy melt, single function and poor adaptability of conventional refining agents, poor stability of casting quality, and insufficient control over the entire process in the existing technology.

[0008] To achieve the above technical objectives, the present invention adopts the following technical solution:

[0009] A method for composite purification of recycled aluminum alloy melt includes the following steps:

[0010] S1. Physical field pretreatment: Physical field pretreatment is performed on the recycled aluminum alloy melt;

[0011] S2. Deep chemical purification: Add a composite refining agent containing rare earth elements to the pretreated melt, stir and let stand to obtain purified recycled aluminum melt.

[0012] Preferably, in the physical field pretreatment step, the magnetic field strength of the magnetic field is 0.5T-2.5T; the inert gas is argon, the flow rate is 1.0-3.0L / min·ton of aluminum liquid, and the refining treatment time is 15-35min.

[0013] Preferably, in the deep chemical purification step, the amount of the composite refining agent added is 0.3%-1.5% of the total mass of the melt, the stirring time is 5-15 min, the standing time is 20-50 min, and the treatment temperature is 720℃-760℃.

[0014] Preferably, the hydrogen content of the purified recycled aluminum melt is <0.10mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is ≤0.50%.

[0015] Preferably, the composite refining agent containing rare earth elements is composed of the following raw materials in parts by mass: 10-15 parts rare earth mixed powder, 5-10 parts sodium fluoride, 4-8 parts calcium fluoride, 8-12 parts potassium chloride, 6-10 parts sodium chloride, 2-5 parts borax, 2-5 parts lithium carbonate, 2-4 parts silicon dioxide, 1-3 parts aluminum oxide, 2-4 parts magnesium fluoride, 3-6 parts potassium carbonate, and 3-6 parts cryolite; the rare earth mixed powder is a mixture of lanthanum-cerium mixed rare earth powder and yttrium powder in a mass ratio of 3:1, wherein the lanthanum-cerium mixed rare earth powder contains ≥45% La2O3 and ≥40% CeO2.

[0016] Preferably, the preparation method of the composite refining agent containing rare earth elements includes the following steps:

[0017] S1: Raw material pretreatment: Place each raw material in a drying oven and dry at 105-110℃ for 3-4 hours to make the moisture content of each raw material less than 0.2%. After drying, pass through a 200-300 mesh sieve for later use.

[0018] S2: Low melting point base material mixing: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 300-400 r / min for 15-20 min to obtain inorganic salt mixed powder;

[0019] S3: Rare earth loaded mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed to 500-600 r / min, stir for 25-30 min to obtain rare earth loaded composite powder.

[0020] S4: Functional component mixing: Add silica, alumina and potassium carbonate to rare earth supported composite powder, stir at 400-500 r / min for 20-25 min to obtain mixed powder;

[0021] S5: Granulation: The mixed powder is fed into a spray granulator, and the granulation temperature is controlled at 80-90℃, the inlet air temperature at 100-110℃, and the outlet air temperature at 60-70℃ to produce 80-120 mesh spherical granules.

[0022] S6: Drying and maturation: Place the spherical particles in a drying oven and dry at 120-130℃ for 2-3 hours to complete the solid-phase reaction maturation and obtain the composite refining agent.

[0023] A one-piece molding process for recycled aluminum alloys includes the following steps:

[0024] S1. Melt preparation: Prepare purified recycled aluminum melt using the method described in any one of claims 1-3;

[0025] S2. Die casting: The purified recycled aluminum melt is die cast to obtain an aluminum alloy casting.

[0026] S3. Intelligent control: The die casting process uses machine learning technology to optimize and control the process parameters.

[0027] Preferably, the die casting process is carried out using die casting equipment that integrates an automatic pouring robot, an automatic part removal robot, an automatic spraying machine, and an in-situ rapid X-ray detector.

[0028] Preferably, the aluminum alloy casting has a tensile strength ≥310MPa, a yield strength ≥260MPa, and an elongation ≥10%.

[0029] Preferably, it also includes the step of establishing a full life cycle service system of "recycling-regeneration-remanufacturing-re-recycling".

[0030] The beneficial effects of this invention compared to the prior art include:

[0031] I. Enhanced Synergy of Purification Process System

[0032] This invention constructs an ordered process system of physical field pretreatment and deep chemical purification, achieving an organic connection between the two purification methods rather than a simple superposition. Physical field pretreatment, through a combination of magnetic field directional flow and argon blowing, completes the initial homogenization of the melt and the separation of large-size inclusions, creating a uniform reaction environment for subsequent chemical purification and ensuring sufficient contact and reaction between the refining agent and the melt. Deep chemical purification relies on the synergistic effect of the multi-components of a self-developed composite refining agent to specifically treat fine impurities and residual hydrogen that are difficult to remove by physical processes. The preceding and following processes form a complementary and coordinated treatment logic. This "preliminary treatment - deep removal" process design solves the problem of single purification processes having a limited treatment dimension, allowing the purification of recycled aluminum alloy melts to form a complete closed-loop process. The treatment effects of each stage support each other, significantly improving the overall synergy and stability of the purification process.

[0033] II. Optimization of Refining Agent System Compatibility

[0034] This invention presents an innovative rare-earth element-containing composite refining agent that overcomes the limitations of conventional refining agents' single function. It employs a precise formulation design based on the complex composition of recycled aluminum alloy melts. The refining agent contains 12 functional raw materials, forming a multi-functional system encompassing rare-earth core impurity removal and refinement, fluoride-directed impurity removal, chloride low-melting-point base material, and multiple auxiliary regulators. Each raw material has a clear division of labor and works synergistically, simultaneously achieving multiple effects such as harmful impurity removal, hydrogen removal, grain refinement, and slag performance optimization, highly matching the impurity treatment requirements of recycled aluminum alloy melts. Compared to conventional refining agents, this system not only broadens the impurity removal range but also improves the melt casting performance, making the chemical purification process more aligned with the actual purification needs of the melt, significantly enhancing the compatibility between the refining agent and the treated object.

[0035] III. Scientific Control of Molding Process Parameters

[0036] This invention integrates machine learning technology into the parameter control process of die casting, replacing the traditional parameter setting method that relies on manual experience, and promoting the scientific and precise development of molding process parameter control. Based on melt purification parameters, real-time melt performance parameters, die casting equipment operating parameters, and casting quality inspection data collected during production, machine learning technology can establish a correlation model between process parameters and casting quality. This model can dynamically adjust die casting process parameters according to variables such as the real-time state of the melt and the production environment, reducing the subjectivity and limitations of manual settings, and ensuring that parameters such as pouring temperature, mold temperature, injection speed, and injection pressure are highly adapted to melt properties. This data-driven parameter control method makes the setting and adjustment of die casting parameters more closely aligned with actual production conditions, effectively improving the stability of casting quality.

[0037] IV. Integration of Die Casting Production Equipment and Processes

[0038] This invention integrates die-casting production equipment and processes, combining automated casting robots, automated part-removal robots, automated spraying machines, and in-situ rapid X-ray detectors into a single unit for die-casting operations. All equipment operates collaboratively according to the production flow, achieving seamless integration of each die-casting step, replacing some manual operations while reducing human error during process changes. The in-situ rapid X-ray detector operates synchronously with the production process, enabling immediate internal quality inspection after casting. Inspection results are fed back to a machine learning model in real time, providing data support for the dynamic optimization of die-casting process parameters. This integrated "casting-forming-part removal-inspection" workflow breaks down the separation between production and inspection, achieving deep integration of die-casting equipment and processes, and improving the continuity of the production process and quality control capabilities.

[0039] V. Construction of Digital Traceability for the Entire Production Process

[0040] This invention leverages an industrial internet platform to build a full lifecycle service system for recycled aluminum alloy production, achieving digital traceability throughout the entire production process. From waste aluminum raw material recycling, melt purification process implementation, refining agent preparation and addition, to die casting production, key production data at each stage can be systematically collected, integrated, and stored, breaking down data barriers between production stages. Staff can quickly query and trace production information at each stage through the platform, accurately pinpointing problem nodes in the production process and providing data support for process optimization and quality improvement. This system not only changes the isolated and difficult-to-trace data situation in traditional production models but also enables targeted recycling and reuse of waste aluminum raw materials, ensuring the compositional stability of recycled aluminum alloy raw materials. This provides raw material support for the stable implementation of melt composite purification processes and refining agents, making the overall process system more aligned with the development needs of a circular economy. Detailed Implementation

[0041] The present invention will be further described in detail below with reference to specific embodiments. It should be emphasized that the following description is merely exemplary and is not intended to limit the scope and application of the present invention.

[0042] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0043] The raw material composition by mass parts is as follows: 10-15 parts rare earth mixed powder, 5-10 parts sodium fluoride, 4-8 parts calcium fluoride, 8-12 parts potassium chloride, 6-10 parts sodium chloride, 2-5 parts borax, 2-5 parts lithium carbonate, 2-4 parts silicon dioxide, 1-3 parts aluminum oxide, 2-4 parts magnesium fluoride, 3-6 parts potassium carbonate, and 3-6 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0044] Preparation steps:

[0045] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 105-110℃ for 3-4 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 200-300 mesh sieve for later use.

[0046] 2. Mixing of low-melting-point base materials: Add sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite to a high-speed mixer and stir at 300-400 r / min for 15-20 min to obtain inorganic salt mixed powder;

[0047] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 500-600 r / min, stir for 25-30 min to obtain rare earth loaded composite powder.

[0048] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 400-500 r / min for 20-25 min to obtain mixed powder;

[0049] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 80-90℃, the inlet air temperature is 100-110℃, and the outlet air temperature is 60-70℃ to produce spherical particles with a particle size of 80-120 mesh.

[0050] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 120-130℃ for 2-3 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0051] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0052] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a strength of 0.5T-2.5T, and argon gas is blown into the melt at a flow rate of 1.0-3.0L / min·ton of aluminum liquid to refine the melt for 15-35 minutes to complete the physical field pretreatment.

[0053] 2. Deep chemical purification: Add 0.3%-1.5% of the above-mentioned self-developed rare earth element composite refining agent to the melt after physical field pretreatment. Stir at 720℃-760℃ for 5-15 minutes, then let stand for 20-50 minutes to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is <0.10mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is ≤0.50%.

[0054] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0055] 1. Melt preparation: Purified recycled aluminum melt is prepared by using any of the above-mentioned composite purification methods for recycled aluminum alloy melt.

[0056] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0057] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0058] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength ≥310MPa, a yield strength ≥260MPa, and an elongation ≥10%.

[0059] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0060] Technical principle of the invention:

[0061] The technical principle of this invention revolves around the synergistic development of the entire chain of "raw materials-process-equipment-system," with the core being the organic cooperation and synergistic effect between the various modules, as detailed below:

[0062] I. Functions and Synergistic Mechanisms of Each Raw Material in Self-Developed Rare Earth Element-Containing Composite Refining Agent

[0063] (I) The core role of each raw material

[0064] 1. Rare Earth Mixed Powder: The core functional component, composed of lanthanum-cerium mixed rare earth powder and yttrium powder in a 3:1 ratio, with La2O3 and CeO2 as the main effective components. It can undergo directional metallurgical reactions with harmful metallic impurities such as V, Ti, Mn, and Cr in the melt to form high-melting-point, low-density rare earth intermetallic compounds; it can also undergo reduction reactions with oxide inclusions to generate rare earth oxide slag; at the same time, it can act as a core agent for refining aluminum alloy grains, adsorbing on the surface of grain nuclei, inhibiting grain growth, and improving casting performance.

[0065] 2. Sodium fluoride + calcium fluoride + magnesium fluoride + cryolite: A multi-component fluoride impurity removal system. Sodium fluoride and calcium fluoride are combined to form a low-melting-point fluoride system, which can react with alkaline earth metal impurities such as magnesium and calcium, destroying the lattice structure of oxide inclusions and promoting the aggregation of fine inclusions into large-sized slag. Magnesium fluoride further improves the impurity removal efficiency and works synergistically with other fluorides to reduce the viscosity of the slag. Cryolite, as a classic aluminum melt refining aid, enhances the adsorption capacity for oxide inclusions and promotes the separation of slag from the melt.

[0066] 3. Potassium chloride + sodium chloride: Alkali metal chloride base materials. The two are compounded to form a low melting point eutectic system, which lowers the overall melting point of the refining agent and allows the refining agent to melt rapidly at the temperature of aluminum alloy melt, providing a uniformly dispersed carrier for other functional components; at the same time, it has a certain degassing effect, which can adsorb hydrogen in the melt and form hydrides that are discharged with the slag.

[0067] 4. Borax + Lithium Carbonate: Melt Flowability and Reactivity Regulators. Borax decomposes to produce B2O3, reducing melt viscosity and improving the reaction contact efficiency between the refining agent and the melt; the Li2O produced by the decomposition of lithium carbonate can react with acidic oxides such as SiO2 in the melt to generate low-melting-point silicate slag, while Li... + It improves the dispersion of rare earth elements in the melt and enhances the removal of impurities and grain refinement of rare earth elements.

[0068] 5. Silica + Alumina: Slag structure modifiers. Both are neutral oxides that can adjust the acidity and alkalinity of the slag, making the interfacial tension between the slag and the aluminum alloy melt moderate, and preventing the slag from adhering to the melt and forming secondary inclusions; at the same time, they can improve the stability of the slag and prevent the slag from decomposing and flowing back into the melt.

[0069] 6. Potassium carbonate: An auxiliary functional component that can regulate the melting rate of the refining agent and prevent local overheating and decomposition of the refining agent; at the same time, it works synergistically with other components to further optimize the performance of slag and improve the stability of the impurity removal and degassing effect.

[0070] (ii) Synergistic effect among raw materials

[0071] 1. Synergistic impurity removal by rare earth elements and fluorides: Fluorides first disrupt the crystal lattice structure of oxide inclusions, causing fine inclusions to aggregate and reducing the binding force between impurities and the melt; rare earth elements then react directionally with the aggregated inclusions and harmful metal impurities, significantly improving the impurity removal efficiency; at the same time, fluorides reduce the viscosity of the slag, allowing rare earth compound slag to quickly separate from the melt and avoid secondary pollution.

[0072] 2. Synergistic dispersion of chloride-based materials and various functional components: The potassium chloride-sodium chloride eutectic system lowers the melting point of refining agents, allowing functional components such as rare earth elements, fluorides, and borax to melt rapidly and disperse evenly in the melt, increasing the contact reaction area between each component and the melt, and solving the problems of uneven dispersion and insufficient reaction of conventional refining agents.

[0073] 3. Synergistic refining of borax, lithium carbonate and rare earth elements: Borax reduces the viscosity of the melt, and lithium carbonate improves the dispersibility of rare earth elements, so that rare earth elements are uniformly adsorbed on the surface of aluminum alloy grain nuclei, maximizing the grain refining effect; at the same time, the refined grains can reduce defects such as porosity and looseness in the melt, and improve the casting performance of the melt.

[0074] 4. Synergistic purification of slag conditioners and functional components: Silica and alumina regulate the acidity and alkalinity and interfacial tension of the slag, enabling the slag generated by various reactions to float quickly and separate stably; potassium carbonate regulates the reaction rate of the refining agent, ensuring the stability and effectiveness of the overall purification process, forming a complete synergistic chain of "impurity removal-separation-stabilization".

[0075] II. Synergistic Mechanism of Composite Purification of Recycled Aluminum Alloy Melt

[0076] Physical field pretreatment provides a pre-process guarantee for deep chemical purification: directional magnetic field flow promotes the aggregation and sedimentation of large inclusions, while argon blowing adsorbs some hydrogen and fine inclusions, achieving melt homogenization and reducing the initial impurity content, thus avoiding insufficient refining agent reaction due to excessively high local impurity concentrations in the melt. Deep chemical purification supplements and deepens the process effect of physical field pretreatment, relying on the synergistic effect of the multi-components of self-developed refining agents to target fine inclusions, low-concentration harmful impurities, and residual hydrogen that are difficult to remove with physical field treatment. The two processes form a "preliminary treatment - deep removal" logic, synergistically achieving efficient removal of hydrogen, various inclusions, and harmful impurities from recycled aluminum alloy melts, ensuring melt purity meets the requirements for high-end casting production.

[0077] III. Process and Equipment Synergy Mechanism of Integrated Molding of Recycled Aluminum Alloys

[0078] 1. Synergistic effect of purified melt and die casting raw materials and processes: The high-purity recycled aluminum alloy melt obtained through composite purification eliminates the material basis for casting defects such as porosity, looseness, and cracks; its uniform composition and good casting performance make the melt have better filling and fluidity during the die casting process, and can accurately fill the complex cavity of the die casting mold; while the process parameters of die casting are dynamically optimized through machine learning technology and precisely matched with the performance characteristics of the purified melt, avoiding forming defects caused by the mismatch between melt performance and process parameters.

[0079] 2. Synergistic effect of machine learning technology and die casting process parameters: The machine learning model establishes the correlation logic between process parameters and casting quality based on multi-dimensional production data. It dynamically adjusts the die casting parameters according to the real-time state of the melt, replacing the traditional manual experience setting mode, reducing the subjectivity and limitations of parameter setting, and ensuring the stability of casting forming quality.

[0080] 3. Synergistic Mechanism of Integrated Die-Casting Equipment Components: An automated pouring robot enables quantitative and constant-speed pouring of purified molten metal, ensuring stable mold filling; an automated spraying machine uniformly coats the mold, preventing castings from sticking and ensuring uniform mold temperature; an automated part-removal robot enables rapid part removal, improving production efficiency; and an in-situ rapid X-ray detector performs real-time internal quality inspection, with results fed back to the machine learning model to provide data support for process parameter optimization. All equipment components form a closed-loop operation process, reducing human error and improving casting forming efficiency and quality control capabilities.

[0081] IV. Synergistic Mechanism between Full Life Cycle Service System and Overall Process

[0082] The full lifecycle service system relies on an industrial internet platform to collect information on waste aluminum raw material recycling, melt purification parameters, refining agent preparation and addition parameters, die casting parameters, and casting quality inspection data, achieving systematic integration and traceability of data at each stage. Data traceability allows for precise location of process nodes where problems occur during melt purification and die casting, providing data support for process optimization and refining agent formulation adjustments. Simultaneously, it enables targeted recycling and reuse of waste aluminum raw materials, ensuring the compositional stability of recycled aluminum alloy raw materials. This provides raw material support for the stable implementation of melt composite purification processes and self-developed refining agents, achieving the circular utilization of recycled aluminum alloy resources and continuous optimization of the production process.

[0083] To make the present invention more fully disclosed, more specific embodiments are described below.

[0084] Example 1:

[0085] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0086] The raw material composition by mass parts is as follows: 10 parts rare earth mixed powder, 5 parts sodium fluoride, 4 parts calcium fluoride, 8 parts potassium chloride, 6 parts sodium chloride, 2 parts borax, 2 parts lithium carbonate, 2 parts silicon dioxide, 1 part aluminum oxide, 2 parts magnesium fluoride, 3 parts potassium carbonate, and 3 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0087] Preparation steps:

[0088] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 105℃ for 3 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 200-mesh sieve for later use.

[0089] 2. Mixing of low-melting-point base materials: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 300 r / min for 15 min to obtain inorganic salt mixed powder;

[0090] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 500 r / min, stir for 25 min to obtain rare earth loaded composite powder.

[0091] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 400 r / min for 20 min to obtain mixed powder;

[0092] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 80℃, the inlet air temperature is 100℃, and the outlet air temperature is 60℃ to produce spherical particles with a particle size of 80 mesh.

[0093] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 120°C for 2 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0094] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0095] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a magnetic field strength of 0.5T, and argon gas is blown into the melt at a flow rate of 1.0L / min·ton of aluminum liquid to refine the melt for 35 minutes, thus completing the physical field pretreatment.

[0096] 2. Deep chemical purification: Add the above-mentioned self-developed rare earth element composite refining agent, accounting for 0.3% of the total mass of the melt, to the melt after physical field pretreatment. Stir at 720℃ for 15 minutes, and then let stand for 50 minutes to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is 0.09mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is 0.48%.

[0097] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0098] 1. Melt preparation: The purified recycled aluminum melt is prepared by using the above-mentioned composite purification method for recycled aluminum alloy melt.

[0099] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0100] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0101] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength of 315.0 MPa, a yield strength of 265.0 MPa, and an elongation of 10.5%.

[0102] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0103] Example 2:

[0104] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0105] The raw material composition by mass parts is as follows: 12 parts rare earth mixed powder, 8 parts sodium fluoride, 6 parts calcium fluoride, 10 parts potassium chloride, 8 parts sodium chloride, 3 parts borax, 3 parts lithium carbonate, 3 parts silicon dioxide, 2 parts aluminum oxide, 3 parts magnesium fluoride, 4 parts potassium carbonate, and 4 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0106] Preparation steps:

[0107] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 108℃ for 3.5 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 250-mesh sieve for later use.

[0108] 2. Mixing of low-melting-point base materials: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 350 r / min for 18 min to obtain inorganic salt mixed powder;

[0109] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 550 r / min, stir for 28 min to obtain rare earth loaded composite powder.

[0110] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 450 r / min for 22 min to obtain mixed powder;

[0111] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 85℃, the inlet air temperature is 105℃, and the outlet air temperature is 65℃ to produce spherical particles with a particle size of 100 mesh.

[0112] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 125°C for 2.5 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0113] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0114] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a magnetic field strength of 1.5T, and argon gas is blown into the melt at a flow rate of 2.0L / min·ton of aluminum liquid to carry out refining treatment on the melt for 25 minutes to complete the physical field pretreatment.

[0115] 2. Deep chemical purification: Add the above-mentioned self-developed rare earth element composite refining agent, accounting for 0.9% of the total mass of the melt, to the melt after physical field pretreatment. Stir at 740℃ for 10 min, then let stand for 35 min to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is 0.05 mL / 100 g Al, and the total amount of impurity elements V+Ti+Mn+Cr is 0.30%.

[0116] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0117] 1. Melt preparation: The purified recycled aluminum melt is prepared by using the above-mentioned composite purification method for recycled aluminum alloy melt.

[0118] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0119] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0120] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength of 335.0 MPa, a yield strength of 270.0 MPa, and an elongation of 11.0%.

[0121] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0122] Example 3:

[0123] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0124] The raw material composition by mass parts is as follows: 13 parts rare earth mixed powder, 7 parts sodium fluoride, 5 parts calcium fluoride, 9 parts potassium chloride, 7 parts sodium chloride, 4 parts borax, 4 parts lithium carbonate, 2 parts silicon dioxide, 1 part aluminum oxide, 2 parts magnesium fluoride, 5 parts potassium carbonate, and 5 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0125] Preparation steps:

[0126] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 106℃ for 3 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 220-mesh sieve for later use.

[0127] 2. Mixing of low-melting-point base materials: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 320 r / min for 16 min to obtain inorganic salt mixed powder;

[0128] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 520 r / min, stir for 26 min to obtain rare earth loaded composite powder.

[0129] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 420 r / min for 21 min to obtain mixed powder;

[0130] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 82℃, the inlet air temperature is 102℃, and the outlet air temperature is 62℃ to produce spherical particles with a particle size of 90 mesh.

[0131] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 122°C for 2.2 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0132] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0133] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a magnetic field strength of 2.0T, and argon gas is blown into the melt at a flow rate of 2.5L / min·ton of aluminum liquid to carry out a refining treatment on the melt for 20 minutes to complete the physical field pretreatment.

[0134] 2. Deep chemical purification: Add the above-mentioned self-developed rare earth element composite refining agent, accounting for 1.2% of the total mass of the melt, to the melt that has been pretreated by physical field. Stir at 750℃ for 7 minutes, and then let stand for 25 minutes to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is 0.06mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is 0.35%.

[0135] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0136] 1. Melt preparation: The purified recycled aluminum melt is prepared by using the above-mentioned composite purification method for recycled aluminum alloy melt.

[0137] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0138] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0139] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength of 328.0 MPa, a yield strength of 272.0 MPa, and an elongation of 10.8%.

[0140] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0141] Example 4:

[0142] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0143] The raw material composition by mass parts is as follows: 15 parts rare earth mixed powder, 10 parts sodium fluoride, 8 parts calcium fluoride, 12 parts potassium chloride, 10 parts sodium chloride, 5 parts borax, 5 parts lithium carbonate, 4 parts silicon dioxide, 3 parts aluminum oxide, 4 parts magnesium fluoride, 6 parts potassium carbonate, and 6 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0144] Preparation steps:

[0145] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 110℃ for 4 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 300-mesh sieve for later use.

[0146] 2. Mixing of low-melting-point base materials: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 400 r / min for 20 min to obtain inorganic salt mixed powder;

[0147] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 600 r / min, stir for 30 min to obtain rare earth loaded composite powder.

[0148] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 500 r / min for 25 min to obtain mixed powder;

[0149] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 90℃, the inlet air temperature is 110℃, and the outlet air temperature is 70℃ to produce spherical particles with a particle size of 120 mesh.

[0150] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 130°C for 3 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0151] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0152] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a magnetic field strength of 2.5T, and argon gas is blown into the melt at a flow rate of 3.0L / min·ton of aluminum liquid to carry out a refining treatment on the melt for 15 minutes to complete the physical field pretreatment.

[0153] 2. Deep chemical purification: Add the above-mentioned self-developed rare earth element composite refining agent, accounting for 1.5% of the total mass of the melt, to the melt after physical field pretreatment. Stir at 760℃ for 5 minutes, then let stand for 20 minutes to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is 0.07mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is 0.40%.

[0154] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0155] 1. Melt preparation: The purified recycled aluminum melt is prepared by using the above-mentioned composite purification method for recycled aluminum alloy melt.

[0156] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0157] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0158] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength of 322.0 MPa, a yield strength of 268.0 MPa, and an elongation of 10.2%.

[0159] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0160] Example 5:

[0161] I. Preparation and Implementation Method of Composite Refining Agents Containing Rare Earth Elements

[0162] The raw material composition by mass parts is as follows: 11 parts rare earth mixed powder, 6 parts sodium fluoride, 7 parts calcium fluoride, 11 parts potassium chloride, 9 parts sodium chloride, 3 parts borax, 4 parts lithium carbonate, 3 parts silicon dioxide, 2 parts aluminum oxide, 3 parts magnesium fluoride, 4 parts potassium carbonate, and 5 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium rare earth powder and yttrium powder in a mass ratio of 3:1.

[0163] Preparation steps:

[0164] 1. Raw material pretreatment: Place each raw material in a drying oven and dry at 107℃ for 3.2 hours to reduce the moisture content of each raw material to below 0.2%; after drying, pass through a 240-mesh sieve for later use.

[0165] 2. Mixing of low-melting-point base materials: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 340 r / min for 17 min to obtain inorganic salt mixed powder;

[0166] 3. Rare earth loading and mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed of the mixer to 540 r / min, stir for 27 min to obtain rare earth loaded composite powder.

[0167] 4. Mixing of functional components: Add silica, alumina and potassium carbonate to the rare earth supported composite powder, stir at 440 r / min for 23 min to obtain mixed powder;

[0168] 5. Granulation and molding: The mixed powder is fed into a spray granulator and spray granulation is used. The granulation temperature is controlled at 84℃, the inlet air temperature is 104℃, and the outlet air temperature is 64℃ to obtain spherical particles with a particle size of 95 mesh.

[0169] 6. Drying and maturation: Place the spherical particles in a drying oven and dry at 124°C for 2.4 hours to complete the solid-phase reaction maturation and obtain the composite refining agent containing rare earth elements.

[0170] II. Implementation Method of Composite Purification Method for Recycled Aluminum Alloy Melt

[0171] 1. Physical field pretreatment: The recycled aluminum alloy melt is placed in a magnetic field with a magnetic field strength of 1.0T, and argon gas is blown into the melt at a flow rate of 1.5L / min·ton of aluminum liquid to refine the melt for 30 minutes, thus completing the physical field pretreatment.

[0172] 2. Deep chemical purification: Add the above-mentioned self-developed rare earth element composite refining agent, accounting for 0.6% of the total mass of the melt, to the melt that has been pretreated by physical field. Stir at 730℃ for 12 minutes, and then let stand for 40 minutes to complete the deep chemical purification and obtain the purified recycled aluminum melt. The hydrogen content of the melt is 0.08mL / 100gAl, and the total amount of impurity elements V+Ti+Mn+Cr is 0.45%.

[0173] III. Implementation Method of Integrated Molding Process for Recycled Aluminum Alloy

[0174] 1. Melt preparation: The purified recycled aluminum melt is prepared by using the above-mentioned composite purification method for recycled aluminum alloy melt.

[0175] 2. Die casting: The purified recycled aluminum melt is transported to the die casting equipment for die casting. The die casting equipment integrates an automatic pouring robot, an automatic part picking robot, an automatic spraying machine, and an in-situ rapid X-ray detector. After forming, aluminum alloy castings are obtained.

[0176] 3. Intelligent control: Machine learning technology is used to optimize and control the die casting process parameters throughout the entire die casting process.

[0177] 4. Finished Product Limitations: The aluminum alloy casting obtained by die casting is a 16-cylinder diesel generator set mixer casting. The casting has a tensile strength of 318.0 MPa, a yield strength of 266.0 MPa, and an elongation of 10.6%.

[0178] 5. Full lifecycle management: Based on the production data of the entire process of melt purification and die casting, establish a full lifecycle service system of "recycling-regeneration-remanufacturing-re-recycling" and realize digital traceability of the entire production process through the industrial Internet platform.

[0179] Comparative Example 1:

[0180] The physical field pretreatment step was omitted, and a deep chemical purification operation was directly performed on the recycled aluminum alloy melt. After treatment, the hydrogen content of the melt was 0.15 mL / 100 g Al, and the total amount of impurity elements V+Ti+Mn+Cr was 0.62%. After forming, the casting had a tensile strength of 290 MPa, a yield strength of 245 MPa, an elongation of 8.5%, and the rest was the same as in Example 2.

[0181] Comparative Example 2:

[0182] In the deep chemical purification step, a rare earth-free composite refining agent accounting for 0.9% of the total mass of the melt was added. After treatment, the hydrogen content of the melt was 0.12 mL / 100 g Al, and the total amount of impurity elements V+Ti+Mn+Cr was 0.58%. After molding, the casting had a tensile strength of 300 MPa, a yield strength of 250 MPa, an elongation of 9.0%, and the rest was the same as in Example 2.

[0183] Comparative Example 3:

[0184] In the die casting process, ordinary die casting equipment without an integrated in-situ rapid X-ray detector was used for die casting. There was no real-time casting inspection and parameter feedback. After processing, the hydrogen content of the melt was 0.05 mL / 100 g Al, and the total amount of impurity elements V+Ti+Mn+Cr was 0.30%. After casting, the tensile strength of the casting was 305 MPa, the yield strength was 258 MPa, the elongation was 9.2%, and the rest was the same as in Example 2.

[0185] Single-factor experiment:

[0186] This invention conducts single-factor process parameter screening experiments and performance index testing experiments. All single-factor experiments are based on Example 2, and the remaining non-investigated parameters are kept consistent with Example 2. The performance index testing covers two core indicators: melt purity and casting mechanical properties. At the same time, the test data of the examples and comparative examples are compared and analyzed.

[0187] Single-factor experiments were conducted to investigate the effects of magnetic field strength, argon flow rate, physical field pretreatment time, amount of composite refining agent added, and chemical deep purification temperature on the hydrogen content and total amount of impurity elements (V+Ti+Mn+Cr) in recycled aluminum alloy melt. Five gradient groups were set up for each experiment, and the test results were the average of three parallel experiments. The melt performance index was judged based on hydrogen content <0.10mL / 100gAl and total amount of impurity elements ≤0.50%.

[0188] 1. Single-factor experiment on magnetic field strength

[0189] The effect of magnetic field strength on melt properties was investigated, with other parameters as follows: argon flow rate 2.0 L / min·ton of molten aluminum, pretreatment time 25 min, refining agent addition 0.9%, and treatment temperature 740℃. The test results are shown in Table 1.

[0190]

[0191] Conclusion and Analysis: When the magnetic field strength is less than 1.5T, the directional stirring effect of the magnetic field on the melt is weak, which cannot effectively promote the aggregation and sedimentation of large inclusions in the melt. The dispersion uniformity of argon bubbles in the melt is also poor, and the adsorption and removal effect on fine inclusions and hydrogen is limited. Therefore, the hydrogen content and total amount of impurity elements in the melt are both at a high level. When the magnetic field strength is greater than 1.5T, the excessively strong magnetic field will cause the melt flow velocity to be too fast, shortening the residence time of argon bubbles in the melt. They will not have enough time to fully adsorb impurities and hydrogen before escaping from the melt. At the same time, the violent flow of the melt is prone to secondary gas entrainment, causing the hydrogen content and total amount of impurity elements in the melt to rise again. The optimal magnetic field strength in this experiment is 1.5T.

[0192] 2. Single-factor experiment on argon gas flow rate

[0193] The effect of argon flow rate on melt properties was investigated. Other parameters included: magnetic field strength 1.5T, pretreatment time 25min, refining agent addition 0.9%, and treatment temperature 740℃. The test results are shown in Table 2.

[0194]

[0195] Conclusion and Analysis: When the argon flow rate is less than 2.0 L / min·ton of molten aluminum, the number of argon bubbles generated in the melt is insufficient, the bubble distribution density is low, the contact area with impurities and hydrogen in the melt is small, and the adsorption and removal efficiency is low, failing to effectively reduce the hydrogen content and total impurities in the melt. When the argon flow rate is greater than 2.0 L / min·ton of molten aluminum, the excessive flow rate causes argon bubbles to merge and form larger bubbles, increasing their rising speed and shortening their residence time in the melt. Simultaneously, the high flow rate of argon impacts the melt, causing surface fluctuations and introducing secondary impurities, resulting in a slight increase in melt performance indicators. The optimal argon flow rate in this experiment is 2.0 L / min·ton of molten aluminum.

[0196] 3. Single-factor experiment on physical field pretreatment time

[0197] The effect of pretreatment time on melt properties was investigated. Other parameters were: magnetic field strength 1.5T, argon flow rate 2.0L / min·ton of aluminum liquid, refining agent addition 0.9%, and treatment temperature 740℃. The test results are shown in Table 3.

[0198]

[0199] Conclusion and Analysis: When the pretreatment time is less than 25 min, the physical field application time is insufficient. The magnetic field's effect on the aggregation and sedimentation of inclusions and the adsorption and removal of hydrogen and fine inclusions by argon gas do not reach equilibrium. As a result, impurities and hydrogen in the melt are not fully removed, leading to poor performance. When the pretreatment time is greater than 25 min, the excessively long treatment time does not further improve the purification effect. Instead, it leads to excessive loss of melt temperature, a slight decrease in melt fluidity, and some settled fine inclusions are easily re-entrained by slightly disturbed melts, resulting in a slight increase in the hydrogen content and total impurities in the melt. The optimal physical field pretreatment time in this experiment is 25 min.

[0200] 4. Single-factor experiment on the amount of compound refining agent added

[0201] The effect of the amount of composite refining agent added on the melt properties was investigated. Other parameters were: magnetic field strength 1.5T, argon flow rate 2.0L / min·ton of aluminum liquid, pretreatment time 25min, and treatment temperature 740℃. The test results are shown in Table 4.

[0202]

[0203] Conclusion and Analysis: When the amount of refining agent added is less than 0.9%, the reaction amount between the refining agent and harmful impurities in the melt is insufficient, and it cannot fully react with impurities such as V, Ti, Mn, Cr, and residual hydrogen. The amount of rare earth compound slag formed is small, the removal of impurities is incomplete, and the melt performance indicators are poor. When the amount of refining agent added is greater than 0.9%, the excessive refining agent will not improve the reaction efficiency. Instead, the unreacted refining agent will remain in the melt, becoming a new source of inclusions, while increasing the amount of slag, slightly affecting the purity of the melt, and causing a slight increase in the hydrogen content and total impurities in the melt. The optimal amount of composite refining agent added in this experiment is 0.9% (as a percentage of the total melt mass).

[0204] 5. Single-factor experiment on temperature for deep chemical purification

[0205] The effect of processing temperature on melt properties was investigated. Other parameters were: magnetic field strength 1.5T, argon flow rate 2.0L / min·ton of aluminum liquid, pretreatment time 25min, and refining agent addition 0.9%. The test results are shown in Table 5.

[0206]

[0207] Conclusion and Analysis: When the processing temperature is below 740℃, the melt has poor fluidity, the composite refining agent disperses slowly and unevenly in the melt, the reaction with impurities is insufficient, the reaction rate is low, and it is difficult to achieve deep purification and degassing, resulting in poor melt performance. When the processing temperature is above 740℃, the excessively high temperature accelerates the hydrogen absorption rate of the melt, while the burn-off rate of rare earth elements increases, the effective components of the refining agent decrease, and the purification effect declines, leading to a rebound in the hydrogen content and total amount of impurity elements in the melt. The optimal chemical deep purification temperature for this experiment is 740℃.

[0208] Performance indicator testing:

[0209] The purity indicators (hydrogen content, total amount of impurity elements V+Ti+Mn+Cr) of the recycled aluminum alloy melt in the five embodiments and three comparative examples of this invention, as well as the mechanical properties (tensile strength, yield strength, elongation) of the castings after die casting, were tested. The melt was tested using a metallographic analyzer and a hydrogen content analyzer, and the mechanical properties of the castings were tested using an electronic universal testing machine. The average value of three parallel experiments was taken for each test. The test results are shown in Tables 6 and 7.

[0210]

[0211]

[0212] Comparative data analysis and theoretical analysis:

[0213] (I) Analysis of Melt Purity Indicators

[0214] In all embodiments, the melt hydrogen content was <0.10 mL / 100 g Al and the total impurity element content was ≤0.50%. Among them, Example 2 had the best melt purity, while the melt performance indicators of the other embodiments decreased slightly due to deviations from the optimal values ​​of process parameters. In Comparative Example 1, due to the lack of a physical field pretreatment step, the melt did not undergo preliminary impurity and degassing. When it was directly subjected to deep chemical purification, the number of impurities that the refining agent needed to treat was large, the reaction was incomplete, and the melt hydrogen content and total impurity element content far exceeded the limit indicators. In Comparative Example 2, because the refining agent did not contain rare earth elements, it could not react directionally with harmful impurities in the melt, and the impurity and degassing effect was greatly reduced. The melt purification process of Comparative Example 3 was the same as that of Example 2, so the melt purity index was the same as that of Example 2, which shows the rationality of the melt purification process.

[0215] From a theoretical perspective, the synergistic effect of physical field pretreatment and deep chemical purification is the core of achieving melt purity standards: physical field pretreatment achieves preliminary homogenization and impurity pre-removal of the melt, creating a favorable reaction environment for chemical purification, while rare earth-based composite refining agents achieve deep impurity removal through directional reactions. The purification system formed by the combination of the two solves the problem of incomplete treatment by a single purification process, which is the key reason why the melt performance indicators of the example are better than those of the comparative example.

[0216] (II) Analysis of the mechanical properties of castings

[0217] In all embodiments, the castings exhibited tensile strength ≥ 310 MPa, yield strength ≥ 260 MPa, and elongation ≥ 10%. Example 2 showed the best mechanical properties, while the mechanical properties of the castings in the other embodiments decreased slightly with decreasing melt purity, remaining generally stable. Comparative Example 1, due to poor melt purity, had defects such as porosity, looseness, and inclusions inside the casting, which became stress concentration points, leading to a significant decrease in tensile strength, yield strength, and elongation. Comparative Example 2 had many harmful impurities remaining in the melt, which formed brittle intermetallic compounds, reducing the toughness and strength of the aluminum alloy matrix. Although Comparative Example 3 met the melt purity standard, the die-casting equipment lacked an integrated in-situ rapid X-ray detector, resulting in no real-time detection and parameter feedback. Minor forming defects during the die-casting process could not be detected and the process adjusted in time, leading to minor structural inhomogeneities inside the casting, thus significantly reducing its mechanical properties compared to Example 2.

[0218] From a theoretical perspective, the mechanical properties of castings are jointly determined by the purity of the melt and the synergy of the die-casting process: high-purity melts eliminate the material basis for internal defects in castings, while integrated die-casting equipment and machine learning-based intelligent control of the forming process achieve precise matching between die-casting parameters and melt properties, ensuring the uniformity of the casting structure. The combination of the two allows the mechanical properties of castings to meet the requirements for use in high-end equipment castings.

[0219] The above description, in conjunction with specific embodiments, provides a further detailed explanation of the present invention. It should not be construed that the specific implementation of the present invention is limited to these descriptions. For those skilled in the art, various substitutions or modifications can be made to these described embodiments without departing from the inventive concept, and all such substitutions or modifications should be considered within the scope of protection of the present invention.

[0220] Although the invention and its advantages have been described in detail, it should be understood that various changes, substitutions, and modifications can be made without departing from the spirit and scope of the invention. Furthermore, the scope of the invention is not limited to the specific embodiments of the processes, methods, and steps described in the specification. From the disclosure of this invention, those skilled in the art will readily utilize existing or future processes, methods, steps that substantially perform the same function or achieve the same results as the corresponding embodiments described herein. Therefore, the appended claims are intended to cover such processes, methods, steps.

Claims

1. A method for composite purification of recycled aluminum alloy melt, characterized in that, Includes the following steps: S1. Physical field pretreatment: Physical field pretreatment is performed on the recycled aluminum alloy melt; S2. Deep chemical purification: Add a composite refining agent containing rare earth elements to the pretreated melt, stir and let stand to obtain purified recycled aluminum melt.

2. The method for composite purification of recycled aluminum alloy melt according to claim 1, characterized in that, In the physical field pretreatment step, the magnetic field strength is 0.5T-2.5T; the inert gas is argon, with a flow rate of 1.0-3.0L / min·ton of molten aluminum, and the refining time is 15-35min.

3. The method for composite purification of recycled aluminum alloy melt according to claim 1, characterized in that, In the chemical deep purification step, the amount of the composite refining agent added is 0.3%-1.5% of the total mass of the melt, the stirring time is 5-15 min, the standing time is 20-50 min, and the treatment temperature is 720℃-760℃.

4. The method for composite purification of recycled aluminum alloy melt according to claim 1, characterized in that, The purified recycled aluminum melt has a hydrogen content of <0.10mL / 100gAl and a total impurity element content of ≤0.50% for V+Ti+Mn+Cr.

5. The method for composite purification of recycled aluminum alloy melt according to claim 1, characterized in that, The composite refining agent containing rare earth elements is composed of the following raw materials by mass: 10-15 parts rare earth mixed powder, 5-10 parts sodium fluoride, 4-8 parts calcium fluoride, 8-12 parts potassium chloride, 6-10 parts sodium chloride, 2-5 parts borax, 2-5 parts lithium carbonate, 2-4 parts silicon dioxide, 1-3 parts aluminum oxide, 2-4 parts magnesium fluoride, 3-6 parts potassium carbonate, and 3-6 parts cryolite; the rare earth mixed powder is a mixture of lanthanum and cerium mixed rare earth powder and yttrium powder in a mass ratio of 3:1, and the lanthanum and cerium mixed rare earth powder contains ≥45% La2O3 and ≥40% CeO2.

6. The method for composite purification of recycled aluminum alloy melt according to claim 5, characterized in that, The preparation method of the composite refining agent containing rare earth elements includes the following steps: S1: Raw material pretreatment: Place each raw material in a drying oven and dry at 105-110℃ for 3-4 hours to make the moisture content of each raw material less than 0.2%. After drying, pass through a 200-300 mesh sieve for later use. S2: Low melting point base material mixing: Sodium fluoride, calcium fluoride, potassium chloride, sodium chloride, and cryolite are added to a high-speed mixer and stirred at 300-400 r / min for 15-20 min to obtain inorganic salt mixed powder; S3: Rare earth loaded mixing: Add rare earth mixed powder, borax, lithium carbonate and magnesium fluoride to inorganic salt mixed powder, adjust the speed to 500-600 r / min, stir for 25-30 min to obtain rare earth loaded composite powder. S4: Functional component mixing: Add silica, alumina and potassium carbonate to rare earth supported composite powder, stir at 400-500 r / min for 20-25 min to obtain mixed powder; S5: Granulation: The mixed powder is fed into a spray granulator, and the granulation temperature is controlled at 80-90℃, the inlet air temperature at 100-110℃, and the outlet air temperature at 60-70℃ to produce 80-120 mesh spherical granules. S6: Drying and maturation: Place the spherical particles in a drying oven and dry at 120-130℃ for 2-3 hours to complete the solid-phase reaction maturation and obtain the composite refining agent.

7. A one-piece molding process for recycled aluminum alloy, characterized in that, Includes the following steps: S1. Melt preparation: Prepare purified recycled aluminum melt using the method described in any one of claims 1-3; S2. Die casting: The purified recycled aluminum melt is die cast to obtain an aluminum alloy casting. S3. Intelligent control: The die casting process uses machine learning technology to optimize and control the process parameters.

8. The integrated forming process for recycled aluminum alloy according to claim 7, characterized in that, The die casting process is carried out using die casting equipment that integrates an automatic pouring robot, an automatic part removal robot, an automatic spraying machine, and an in-situ rapid X-ray detector.

9. The integrated forming process for recycled aluminum alloy according to claim 7, characterized in that, The aluminum alloy casting has a tensile strength ≥310MPa, a yield strength ≥260MPa, and an elongation ≥10%.

10. The integrated forming process for recycled aluminum alloy according to claim 7, characterized in that, It also includes steps to establish a full life-cycle service system of "recycling-regeneration-remanufacturing-re-recycling".

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