Low-energy preparation method of aluminum alloy machining scrap regenerated nanometer aluminum oxide composite powder

Abstract

The invention discloses a low-energy preparation method of aluminum alloy machining scrap regenerated nanometer aluminum oxide composite powder. The low-energy preparation method comprises the following steps: cleaning machining scraps; powder is prepared through in-situ reaction; separating reaction products; and carrying out air calcination, and carrying out a reaction on liquid metal and aluminum alloy machining chippings to obtain the nano-structure aluminum oxide-based composite powder. According to the method, aluminum alloy machining scraps are adopted as raw materials, waste utilization is achieved, an additional product H2 serves as clean energy and can be recycled, the whole preparation technology has the advantages of being simple in operation process, low in energy consumption, efficient, environmentally friendly and the like, and the prepared nanometer aluminum oxide composite powder is uniform in particle size distribution, small in particle size, high in yield and suitable for industrial production. The requirements of the fields of ceramics, electronics, biomedicine, catalyst carriers and the like on high-quality alumina-based composite powder can be met, and the method is suitable for batch production.

Description

Technical Field

[0001] The invention belongs to the technical field of preparation of alumina composite powders, and in particular relates to a low-energy preparation method of nano alumina composite powders regenerated from aluminum alloy machining debris. Background Art

[0002] Nano-alumina composite powder has many advantages such as high specific surface area, good temperature resistance, high hardness, good dispersibility and good chemical stability. It is widely used in the fields of ceramics, electronics, biomedicine and catalyst carriers.

[0003] The main methods for preparing alumina-based oxide composite powders include chemical precipitation, sol-gel, hydrothermal, mechanical alloying, etc. Nano-alumina composite powders with regular morphology and uniform particle size distribution can be prepared by chemical methods. However, it is necessary to precisely control and operate multiple links such as dissolution, precipitation reaction, filtration, drying, and calcination of raw materials, and the process requirements are relatively high. If the pH, reaction temperature, concentration and other parameters of the solution need to be precisely controlled, otherwise the product quality will be affected. In addition, there are serious environmental pollution problems in the use of chemical powder making. A large amount of pollutants such as wastewater, waste gas and waste residue are generally generated during the powder making process. If not handled properly, it will cause a heavy burden on the environment. The operation process of preparing nano-alumina powder by mechanical alloying is relatively simple, but the quality of the product is difficult to accurately control, such as uneven particle size distribution, irregular shape, and easy introduction of impurities. The energy consumption of preparing nano-powders by high-energy ball milling is relatively high, and the output is low, which is difficult to meet the needs of large-scale production.

[0004] In order to obtain nanostructured alumina composite powder, the existing Chinese invention patent "Alumina composite oxide and its preparation method" with application number 201510344723.8 discloses a preparation method, the steps of which are preparation of metal nitrate solution, precipitation in alkaline solution, aging, dehydration, drying, calcination at 700-900℃ for 3-10h to obtain alumina composite oxide. This method can prepare alumina-based oxide composite powder with high specific surface area, but the process is complicated, the reaction temperature is high, and the experimental cycle is long; and the precipitation reaction using nitrate, alkaline solution, etc. is easy to produce pollutants such as wastewater and waste residue, which will cause environmental pollution if not properly handled. Summary of the invention

[0005] The technical problem to be solved by the present invention is to provide a low-energy preparation method for regenerating nano-alumina composite powder from aluminum alloy machining debris, which has the characteristics of short process flow, simple operation, high preparation efficiency and low energy consumption.

[0006] The technical solution adopted by the present invention to solve the above technical problems is: a low-energy preparation method of aluminum alloy machining debris regenerated nano-alumina composite powder, characterized by comprising the following steps:

[0007] 1) Processing debris cleaning: Aluminum alloy machine chips are used as raw materials, water-based cleaning agents are used as the medium, and ultrasonic cleaning is used to clean aluminum alloy machine chips, pre-treat the surface oil and dust, and further clean them with deionized water;

[0008] 2) Preparation of powder by in-situ reaction: Weigh the cleaned aluminum alloy machining debris, spray low melting point liquid metal on its surface, let it stand for 3 to 8 minutes, then spray deionized water, and carry out in-situ reaction at room temperature. Add an equal amount of deionized water every 4 to 6 minutes until the reaction is completed;

[0009] 3) Separation of reaction products: centrifugal filtration of the reaction products to remove liquid metal from the reaction products;

[0010] 4) Calcination: The filtered powder is sieved and calcined in air in a tube furnace to remove crystal water, and finally a nanostructured alumina-based composite powder is obtained.

[0011] Preferably, the aluminum alloy machining scraps in step 1) are weighed from one of 7075, 6061 or 4043 series aluminum alloys.

[0012] Furthermore, the ultrasonic cleaning time in step 1) is 10 to 20 minutes; the water-based cleaning agent is selected from fatty alcohol polyoxyethylene ether or alkylphenol polyoxyethylene ether, or citric acid and other cleaning agents.

[0013] Preferably, in the step 2), the weight of the cleaned aluminum alloy chips weighed is 30 to 100 g.

[0014] Furthermore, the low melting point liquid metal in step 2) is at least one of Ga or Ga-In series low melting point liquid metals.

[0015] Furthermore, the volumes of the low melting point liquid metal and water sprayed in step 2) are both 5 to 15 ml.

[0016] Furthermore, in the step 2), an equal amount of deionized water is added every 4 to 6 minutes until the reaction is completed.

[0017] Furthermore, the centrifugal filtration in step 3) has a centrifugal rate of 2000-4000 rpm.

[0018] Furthermore, the temperature range of the air calcination in the tubular furnace in step 4) is 300-500° C., and the temperature is kept for 30-90 minutes.

[0019] Finally, the average particle size of the nanostructured alumina-based composite powder finally obtained in step 4) is less than 100 nm.

[0020] Compared with the prior art, the advantages of the present invention are: the use of aluminum alloy machining debris as raw materials to prepare nano-alumina composite powder not only realizes the recycling of waste materials, but also the additional product H2 is an eco-friendly clean energy that can be recycled, and the aluminum alloy machining debris has a larger specific surface area than the bulk material, which is conducive to improving the reaction rate; the liquid metal Ga and Ga-In exist in the form of catalysts, and the consumption is very small. The liquid metal after centrifugal separation can be reused. The preparation process of the present invention has the advantages of simple operation process, low energy consumption, high efficiency, green environmental protection, etc. The prepared nano-alumina composite powder has uniform particle size distribution, fine particles, and high yield, which can meet the needs of ceramics, electronics, biomedicine, and catalyst carriers for high-quality alumina-based composite powders, and is suitable for mass production. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 This is a TEM image of alumina-based composite powder prepared using T6 state 7075 high-strength aluminum as raw material in Example 1 of the present invention. DETAILED DESCRIPTION

[0022] The present invention is further described in detail below with reference to the embodiments.

[0023] Example 1: Preparation of nano-Al2O3-ZnO-MgO-CuO oxide composite powder

[0024] The main components of 7075 aluminum alloy are zinc (Zn), magnesium (Mg) and copper (Cu). The zinc content is relatively high, about 5.1% to 6.1%, the magnesium content is about 2.1% to 2.9%, and the copper content is 1.2% to 2%. In addition, it also contains a small amount of manganese (Mn), chromium (Cr) and other elements. The manganese content is usually below 0.3%, and the chromium content is about 0.18% to 0.28%. The rest is mainly aluminum (Al). T6 state high-strength 7075 aluminum alloy processing debris is selected as raw material to prepare a nano-composite powder preparation method with Al2O3 as the main phase and doped with various oxides such as ZnO, MgO, CuO, etc. The specific steps are as follows:

[0025] 1. Cleaning of machining debris: Using fatty alcohol polyoxyethylene ether water-based cleaning agent as the medium, ultrasonic cleaning is used to clean the machining debris of T6 state high-strength 7075 aluminum alloy for 10 minutes, pre-treating the surface oil and dust, and further cleaning with deionized water;

[0026] 2. Preparation of powder by in-situ reaction: Weigh 30g of cleaned 7075 aluminum alloy machining chips, spray 5ml of low-melting-point Ga liquid metal on its surface, let it stand for 3min, spray 5ml of deionized water, and carry out in-situ reaction at room temperature. Add an equal amount of deionized water every 4min until the reaction is completed.

[0027] 3. Separation of reaction products: The reaction products are centrifuged at a rate of 2000 rpm to remove liquid metal Ga.

[0028] 4. Calcination: The filtered powder is sieved and calcined in a tubular furnace at 300°C for 90 minutes to remove crystal water to obtain nano-Al2O3-ZnO-MgO-CuO oxide composite powder.

[0029] Example 1 The TEM results of alumina-based composite powder prepared using T6 state 7075 high-strength aluminum as raw material are shown in the attached figure. Figure 1 As shown, it can be seen that the particle size distribution is uniform and the average grain size is below 100nm.

[0030] Example 2: Preparation of nano-Al2O3-SiO2-MgO oxide composite powder

[0031] The main components of 6061 aluminum alloy include magnesium (Mg), silicon (Si), etc., among which the magnesium content is 0.8-1.2%, the silicon content is 0.4-0.8%, and it also contains a small amount of copper (Cu) of about 0.15-0.4%, manganese (Mn) of about 0.15%, chromium (Cr) of about 0.04-0.35%, zinc (Zn) not more than 0.25% and titanium (Ti) not more than 0.15%, and the rest is aluminum (Al). Select T6 state high-strength 6061 aluminum alloy processing debris as raw material, prepare Al2O3 as the main phase, SiO2 and MgO and other oxides doped nanocomposite powder, the specific steps are as follows:

[0032] 1. Cleaning of machining debris: Using alkylphenol polyoxyethylene ether water-based cleaning agent as the medium, ultrasonic cleaning is used to clean the machining debris of T6 state high-strength 6061 aluminum alloy for 15 minutes, pre-treating the surface oil and dust, and further cleaning with deionized water;

[0033] 2. Preparation of powder by in-situ reaction: Weigh 60 g of cleaned 6061 aluminum alloy machining chips, spray 10 ml of low-melting-point Ga-In liquid metal on its surface, let it stand for 5 minutes, spray 10 ml of deionized water, and carry out in-situ reaction at room temperature. Add an equal amount of deionized water every 5 minutes until the reaction is completed.

[0034] 3. Separation of reaction products: The reaction products are centrifuged and filtered at a centrifugal rate of 3000 rpm to remove liquid metal Ga-In.

[0035] 4. Calcination: The filtered powder is sieved and calcined in a tubular furnace at 400°C for 60 minutes to remove crystal water to obtain nano-Al2O3-SiO2-MgO oxide composite powder.

[0036] In Example 2, the alumina-based composite powder prepared by using T6 state 6061 aluminum alloy as raw material has a uniform particle size distribution and an average grain size of less than 100 nm.

[0037] Example 3: Preparation of nano-Al2O3-SiO2 oxide composite powder

[0038] The main component of 4043 aluminum alloy is aluminum, and the remaining components include silicon (content of about 4.5% to 6.0%), iron content not exceeding 0.8%, copper not exceeding 0.30%, manganese not exceeding 0.05%, magnesium not exceeding 0.05%, zinc not exceeding 0.10%, and titanium not exceeding 0.20%. The method for preparing a nano-composite powder with Al2O3 as the main phase and doped with various oxides such as SiO2 and MgO is selected from the rolled 4043 aluminum alloy processing debris as raw materials, and the specific steps are as follows:

[0039] 1. Cleaning of machining debris: Using citric acid water-based cleaning agent as the medium, ultrasonic cleaning is used to clean the machining debris of rolled 4043 aluminum alloy for 20 minutes, pre-treating the surface oil and dust, and further cleaning with deionized water;

[0040] 2. Preparation of powder by in-situ reaction: Weigh 100 g of cleaned 4043 aluminum alloy machining chips, spray 15 ml of low-melting-point Ga-In liquid metal on its surface, let it stand for 8 minutes, spray 15 ml of deionized water, and carry out in-situ reaction at room temperature. Add an equal amount of deionized water every 6 minutes until the reaction is completed.

[0041] 3. Separation of reaction products: The reaction products are centrifuged and filtered at a centrifugal rate of 4000 rpm to remove liquid metal Ga-In.

[0042] 4. Calcination: The filtered powder is sieved and calcined in a tubular furnace at 500°C for 30 minutes to remove crystal water to obtain nano-Al2O3-SiO2 oxide composite powder.

[0043] In Example 3 of the present invention, the alumina-based composite powder prepared by using rolled 4043 aluminum alloy as a raw material has a uniform particle size distribution and an average grain size of less than 100 nm.

[0044] The protection scope of this patent focuses on the core process of preparing alumina composite powder, including but not limited to pretreatment steps such as cleaning of processing debris, preparing powder by in-situ reaction, separation of reaction products, and air calcination. The preparation of nano-composite powder by reacting low-melting-point liquid metal with aluminum alloy is the unique innovation of this patent. The material selection includes but is not limited to Ga, Ga-In liquid metal, 7075 aluminum alloy, and 6061 aluminum alloy in the embodiments. This technology can be extended to more alloy systems to prepare nano-oxide composite powders of different systems, all of which belong to the protection scope of the patent of this invention.

[0045] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the technical principles of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A low-energy preparation method for regenerating nano-alumina composite powder from aluminum alloy machining debris, characterized in that The following steps are involved: 1) Processing debris cleaning: Aluminum alloy machine chips are used as raw materials, water-based cleaning agents are used as the medium, and ultrasonic cleaning is used to clean aluminum alloy machine chips, pre-treat the surface oil and dust, and further clean them with deionized water; 2) Preparation of powder by in-situ reaction: Weigh the cleaned aluminum alloy machining debris, spray low melting point liquid metal on its surface, let it stand for 3 to 8 minutes, then spray deionized water, and carry out in-situ reaction at room temperature. Add an equal amount of deionized water every 4 to 6 minutes until the reaction is completed; 3) Separation of reaction products: centrifugal filtration of the reaction products to remove liquid metal from the reaction products; 4) Calcination: The filtered powder is sieved and calcined in air in a tube furnace to remove crystal water, and finally a nanostructured alumina-based composite powder is obtained.

2. The low-energy preparation method according to claim 1, characterized in that: The aluminum alloy machining scraps in step 1) are selected from 7075, 6061 or 4043 series aluminum alloys.

3. The low-energy preparation method according to claim 1, characterized in that: The ultrasonic cleaning time in step 1) is 10 to 20 minutes; the water-based cleaning agent is selected from fatty alcohol polyoxyethylene ether, alkylphenol polyoxyethylene ether or citric acid cleaning agent.

4. The low-energy preparation method according to claim 1, characterized in that: In the step 2), the weight of the cleaned aluminum alloy chips is 30 to 100 g.

5. The low-energy preparation method according to claim 1, characterized in that: The low melting point liquid metal in step 2) is at least one of Ga or Ga-In series low melting point liquid metals.

6. The low-energy preparation method according to claim 1, characterized in that: The volumes of the low melting point liquid metal and water sprayed in step 2) are both 5-15 ml.

7. The low-energy preparation method according to claim 1, characterized in that: In the step 2), an equal amount of deionized water is added every 5 minutes until the reaction is completed.

8. The low-energy preparation method according to claim 1, characterized in that: The centrifugal filtration in step 3) is carried out at a centrifugal rate of 2000-4000 rpm.

9. The low-energy preparation method according to claim 1, characterized in that: The temperature range of the tubular furnace air calcination in step 4) is 300-500° C., and the temperature is kept for 30-90 minutes.

10. The low-energy preparation method according to claim 1, characterized in that: The average particle size of the nanostructured alumina-based composite powder finally obtained in step 4) is less than 100 nm.

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