Powdered recycling method for aluminum-based composite materials

Abstract

This application relates to a method for the powder recycling of aluminum-based composite materials. The method involves cutting aluminum-based composite material waste into sheets, crushing the sheets into centimeter-sized particles, then micro-heating the particles in an inert atmosphere followed by cooling in a non-oxidizing atmosphere. Selective microwave heating creates thermal adaptation, generating more microcracks and defects, which become the starting point for fragmentation. Simultaneously, alternating heating and cooling creates thermal fatigue cracks, creating stress concentration conditions in specific areas of the composite material's surface. Finally, the material is pulverized in an inert atmosphere to obtain high-purity, highly dispersed, highly uniform, and environmentally friendly powdered aluminum-based composite materials.

Description

Technical Field

[0001] This invention relates to aluminum-based composite materials, and more particularly to a method for the powder-based recycling of aluminum-based composite materials. Background Technology

[0002] Aluminum-based materials refer to materials based on metallic aluminum. Aluminum-based composite materials are composite structural materials formed by combining an aluminum matrix with other materials (such as fiber-reinforced materials, particulate-reinforced materials, etc.). These composite materials typically possess higher strength, stiffness, and wear resistance while maintaining lower weight. Their applications include aerospace, automotive manufacturing, shipbuilding, electronic packaging, and sporting goods. They are also commonly used in the manufacture of aircraft shells, automotive body parts, ship structures, and electronic heat sinks. With the widespread use of aluminum-based composite materials and the introduction of dual-carbon goals, the recycling and reuse of aluminum-based composite materials has become urgent. According to statistics from relevant organizations, the CO2 emissions from recycling 1 ton of green aluminum are only 1 / 10 of those from electrolytically producing 1 ton of aluminum, demonstrating the considerable economic benefits and effective environmental protection of recycling aluminum-based materials.

[0003] However, aluminum-based composites typically possess both toughness and strength, making them generally difficult to pulverize. Furthermore, the brittleness of aluminum-based composites depends on various factors, including material properties, alloy composition, processing methods, and usage conditions. These factors can all influence the pulverization process, introducing difficulties and uncertainties to the process and results, and ultimately increasing pulverization costs. For example, patent (A method for reusing waste particle-reinforced aluminum-based composite materials 2023105567192) mentions a method of T6 heat treatment on aluminum-based composites, which increases the material's hardness by altering its microstructure, thereby facilitating its crushing. Furthermore, according to some currently available patent information, whether it is recycling through smelting or powder metallurgy (e.g., a method for preparing clustered aluminum matrix composites using graphene-reinforced aluminum matrix composite waste 2020108677491; a method for preparing clustered aluminum matrix composites using recycled SiCp / Al composites 2018102448561; a method for preparing castings using ceramic particle-reinforced aluminum matrix composite waste 2023104329144), the bulk material needs to be crushed.

[0004] Therefore, how to provide a powder recycling method for aluminum-based composite materials that is high in purity, highly dispersed, highly uniform, and has a green, clean, and environmentally friendly process has become a current research hotspot. Summary of the Invention

[0005] Therefore, it is necessary to provide a powder recycling method for aluminum-based composite materials that is highly pure, highly dispersed, highly uniform, and has a green, clean, and environmentally friendly process.

[0006] A method for the powder recycling of aluminum-based composite materials includes the following steps:

[0007] Provide aluminum-based composite material waste;

[0008] After cleaning, the waste material is cut into sheets;

[0009] The sheet material is crushed to obtain centimeter-sized granular material;

[0010] The particulate material was microwave-heated in an inert atmosphere and then cooled in a non-oxidizing atmosphere to obtain a cooled sample.

[0011] The cooled sample was pulverized in an inert atmosphere to obtain a powdered aluminum-based composite material.

[0012] In one embodiment, the step of microwave heating the particulate material in an inert atmosphere specifically involves: microwave heating the particulate material in an inert atmosphere to 120°C to 550°C and holding it at that temperature for 0 to 30 minutes.

[0013] In one embodiment, the heating rate of the microwave heating is 10°C / min to 150°C / min.

[0014] In one embodiment, the non-oxidizing atmosphere is an inert atmosphere or a mixture of a reducing gas and an inert gas; the inert atmosphere is an inert gas atmosphere, preferably nitrogen or argon; the preferred reducing gas is hydrogen.

[0015] In one embodiment, the crushing is carried out using a jaw crusher, cone crusher, hammer crusher, roller crusher, or impact crusher.

[0016] In one embodiment, the pulverization is performed using an air jet mill or a ball mill.

[0017] In one embodiment, the average size of the particulate material is 0.1 cm to 3.0 cm.

[0018] In one embodiment, prior to the step of pulverizing the cooled sample in an inert atmosphere, the cooling sample is further subjected to repeated microwave heating and cooling in a non-oxidizing atmosphere until obvious cracks appear on the surface of the cooled sample.

[0019] The above-mentioned method for the powder recycling of aluminum-based composite materials involves cutting aluminum-based composite material waste into sheets, crushing the sheets into centimeter-sized particles, then heating the particles in an inert atmosphere using microwaves and cooling them in a non-oxidizing atmosphere. Selective microwave heating creates thermal adaptation, generating more microcracks and defects, which become the starting point for crushing. Simultaneously, alternating heating and cooling creates thermal fatigue cracks, creating stress concentration conditions in specific areas of the composite material's surface. Finally, the material is pulverized in an inert atmosphere to obtain high-purity, highly dispersed, highly uniform, and environmentally friendly powdered aluminum-based composite materials. Attached Figure Description

[0020] Figure 1 This is a particle size distribution diagram of the powder material prepared in Example 1;

[0021] Figure 2 SEM image of the powder material prepared in Example 1;

[0022] Figure 3 The particle size distribution diagram is for the powder material prepared in Comparative Example 1. Detailed Implementation

[0023] To facilitate understanding of the present invention, a more comprehensive description is provided below, along with preferred embodiments. However, the present invention can be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a thorough and complete understanding of the disclosure of the present invention.

[0024] 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 invention pertains. The terminology used herein in the description of the invention is for the purpose of describing particular embodiments only and is not intended to be limiting of the invention.

[0025] A method for the powder recycling of aluminum-based composite materials according to one embodiment includes the following steps S110 to S150:

[0026] S110, providing aluminum-based composite material waste;

[0027] In this embodiment, the aluminum-based composite material waste is scrapped or substandard silicon carbide particle-reinforced aluminum-based composite brake discs.

[0028] S120. After cleaning the above-mentioned waste materials, cut them into sheets.

[0029] It should be noted that cleaning is mainly for removing impurities from the surface of the waste material.

[0030] In this embodiment, the cleaned waste material can be cut into sheets of about 10cm to facilitate subsequent crushing.

[0031] Furthermore, the cleaned waste can be cut into sheets of 3cm to 8cm to facilitate subsequent crushing.

[0032] It is understandable that if the waste material itself is a thin sheet or a small block of material, the cutting step can be omitted.

[0033] S130. The above sheet material is crushed to obtain centimeter-sized granular material.

[0034] In this embodiment, crushing is carried out using a jaw crusher, cone crusher, hammer crusher, roller crusher, or impact crusher.

[0035] The crushers mentioned above are all commonly used existing crushers, and will not be described in detail here.

[0036] Furthermore, the sheet material can be crushed into granular materials with an average size of 0.1cm to 3.0cm. On the one hand, this increases the surface area of ​​the particles exposed to microwaves and non-oxidizing atmospheres, thereby causing cracks to appear on the particle surface more quickly. On the other hand, the distribution of particles with an average size of 0.1cm to 3.0cm in physical space is more uniform, which can reduce the uneven processing caused by particle accumulation and is also more conducive to subsequent crushing processing, improving recycling efficiency and effect.

[0037] S140. The above particulate material is microwave-heated in an inert atmosphere and then cooled in a non-oxidizing atmosphere to obtain a cooled sample.

[0038] The inert atmosphere is an inert gas atmosphere, and the inert gas is argon or nitrogen.

[0039] The specific steps of microwave heating the above-mentioned particulate material in an inert atmosphere are as follows: microwave heating the above-mentioned particulate material in an inert atmosphere to 120℃~550℃ and holding it at that temperature for 0~30min, so as to ensure that microwave energy is effectively absorbed and heat is generated without damaging the internal structure of the aluminum matrix composite material, so as to generate sufficient interfacial thermal stress inside the particles.

[0040] In this embodiment, the heating rate of microwave heating is 10℃ / min to 150℃ / min, which allows the particles to uniformly absorb microwave energy and generate heat, preventing local overheating from affecting the material properties. At the same time, it can also generate sufficient interfacial thermal mismatch inside the particles.

[0041] Microwave heating of particulate materials in an inert atmosphere creates thermal mismatch through selective microwave heating, generating more microcracks and defects that become the starting point for breakage. Simultaneously, cooling in a non-oxidizing atmosphere creates thermal fatigue cracks through alternating hot and cold temperatures, creating stress concentration conditions in specific areas at the surface of the composite material, thus providing favorable conditions for further pulverization.

[0042] In this embodiment, the non-oxidizing atmosphere is an inert atmosphere or a mixture of a reducing atmosphere and an inert atmosphere, wherein the inert atmosphere is an inert gas atmosphere, and the inert gas is nitrogen or argon. The reducing gas is hydrogen. By microwaving the particulate material in an inert atmosphere and then cooling it in a non-oxidizing atmosphere, it is possible to effectively prevent the particulate material from reacting with oxygen or other reactive gases, thus affecting its recovery efficiency.

[0043] It should be noted that, in order to facilitate subsequent pulverization, the cooled sample can repeat step S140, that is, repeatedly subject the cooled sample to microwave heating and cooling in a non-oxidizing atmosphere until obvious cracks appear on the surface of the cooled sample.

[0044] S150. The cooled sample is pulverized in an inert atmosphere to obtain a powdered aluminum-based composite material.

[0045] In this embodiment, the pulverization is carried out using an air jet mill or a ball mill.

[0046] The air jet mill or ball mill used in the above-mentioned pulverization is a commonly used existing pulverization equipment, and will not be described in detail here.

[0047] In this embodiment, the inert atmosphere is an inert gas atmosphere, and the inert gas is nitrogen or argon.

[0048] This application utilizes the characteristics of microwave selective heating, thermal cycling, and heterogeneous interfaces of composite materials to provide a powder recycling method for aluminum-based composite materials. This method is simple and reliable, and the obtained composite powder product has good stability and controllable particle size distribution. The preparation process is green, clean, and environmentally friendly, and can realize the recycling of high-purity, highly uniform, and highly dispersed aluminum-based composite material powders.

[0049] The following are specific examples:

[0050] Example 1

[0051] We provide scrapped silicon carbide particle-reinforced aluminum matrix composite brake discs with a diameter greater than 50cm.

[0052] After cleaning the surface of the brake disc, cut it into sheets;

[0053] The sheet material is fed into a roller crusher for crushing to obtain granular material with an average size of 3cm;

[0054] The above particulate material was microwave heated to 550°C in a nitrogen atmosphere, held at that temperature for 20 minutes, and then cooled in a nitrogen atmosphere to obtain a cooled sample. The heating rate of the microwave heating was 150°C / min.

[0055] The cooled sample was placed in an air jet mill for pulverization. An inert gas was used as the medium in the air jet mill, and the gas flow rate and pressure were controlled to obtain micron-sized powder with the following particle size distribution: Figure 1 As shown, the morphology of the particles is as follows Figure 2 As shown.

[0056] Comparative Example 1

[0057] Comparative Example 1 is basically the same as Example 1, except that Comparative Example 1 omits the step of microwaving the particulate material in a nitrogen atmosphere to 550°C, holding it at that temperature for 20 minutes, and then cooling it in a nitrogen atmosphere to obtain a cooled sample. Instead, the particulate material is directly placed into an air jet mill for pulverization.

[0058] The powder material obtained in Comparative Example 1 has the following particle size distribution: Figure 3 As shown.

[0059] Depend on Figure 1 and Figure 3 The comparison shows that the powder recycling method for aluminum-based composite materials provided in this application can obtain finer, more uniform, and more dispersed aluminum-based composite material powder.

[0060] Example 2

[0061] We provide scrap aluminum-based composite brake discs with a diameter of 65cm;

[0062] The brake disc was cleaned and then cut into sheets.

[0063] The sheet material is crushed in a hammer crusher to obtain granular material with an average size of 1cm.

[0064] The particulate material was microwave heated to 380°C in an argon atmosphere and held for 30 minutes. Then it was cooled in a mixed atmosphere of nitrogen and hydrogen. This step was repeated until obvious cracks appeared on the surface of the cooled sample. The heating rate of microwave heating was 10°C / min.

[0065] The cooled sample was placed in a ball mill filled with argon gas. The number and rotation speed of the grinding balls were controlled to obtain submicron powder.

[0066] Example 3

[0067] Substandard aluminum-based composite brake discs with a diameter greater than 30cm were supplied.

[0068] The brake disc was cleaned and then cut into sheets.

[0069] The sheet material is fed into a jaw crusher for crushing to obtain granular material with an average size of 0.1 cm.

[0070] The particulate material was microwave-heated to 120°C in a nitrogen atmosphere, held at that temperature for 15 minutes, and then cooled in an argon atmosphere to obtain a cooled sample. The heating rate of the microwave heating was 80°C / min.

[0071] The cooled sample was placed in a ball mill for pulverization. Nitrogen gas was used as the medium, and the speed and time of the ball mill were controlled to obtain fine powder at the micrometer level.

[0072] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the present invention. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these modifications and improvements all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A method for the powder-based recycling of aluminum-based composite materials, characterized in that, Includes the following steps: Provide aluminum-based composite material waste; After cleaning, the waste material is cut into sheets; The sheet material is crushed to obtain centimeter-sized granular material with an average size of 0.1cm to 3.0cm. The particulate material was microwave-heated in an inert atmosphere and then cooled in a non-oxidizing atmosphere to obtain a cooled sample. The cooled sample was pulverized in an inert atmosphere to obtain a powdered aluminum-based composite material. The specific steps of microwave heating the particulate material in an inert atmosphere are as follows: microwave heating the particulate material in an inert atmosphere to 120℃~550℃ and holding it at that temperature for 15~30 minutes. The heating rate of the microwave heating is 10℃ / min to 150℃ / min.

2. The method for powdering and recycling aluminum-based composite materials according to claim 1, characterized in that, The non-oxidizing atmosphere is an inert atmosphere or a mixture of a reducing gas and an inert gas. The inert atmosphere is an inert gas atmosphere, and the inert gas is nitrogen or argon. The reducing gas is hydrogen.

3. The method for powder recycling of aluminum-based composite materials according to claim 1, characterized in that, The crushing is carried out using a jaw crusher, cone crusher, hammer crusher, roller crusher, or impact crusher.

4. The method for powder recycling of aluminum-based composite materials according to claim 1, characterized in that, The pulverization is carried out using an air jet mill or a ball mill.

5. The method for powder recycling of aluminum-based composite materials according to any one of claims 1 to 4, characterized in that, Before the step of pulverizing the cooled sample in an inert atmosphere, the method further includes repeatedly subjecting the cooled sample to microwave heating and cooling in a non-oxidizing atmosphere until obvious cracks appear on the surface of the cooled sample.

Images