Manufacturing method for preparing foamed aluminum by fully recovering aluminum

Abstract

The invention relates to a manufacturing method for preparing foamed aluminum from fully recycled aluminum, which comprises the following steps of: melting the fully recycled aluminum at high temperature to form molten aluminum, and maintaining the molten aluminum in a semi-solid molten aluminum state; an aluminum slag grinding step of grinding the recycled aluminum slag into aluminum slag powder; a viscosity control step: adding the aluminum slag powder into the semi-solid molten aluminum, continuously stirring, and controlling the viscosity of the semi-solid molten aluminum to be 1-3 mpa.s; a gas injection foaming step of injecting gas into the semi-solid molten aluminum from the lower part so that the gas is uniformly distributed in the semi-solid molten aluminum to form foamed molten aluminum; a cooling molding step of cooling the foamed aluminum melt containing the gas foam to form foamed aluminum; therefore, the invention provides the foamed aluminum manufacturing method which takes the fully recycled aluminum as a raw material and controls the viscosity of the molten liquid, so that bubbles are uniformly distributed, and the overall production benefit of the foamed aluminum can be improved.

Description

Technical Field

[0001] The present invention is a method for preparing foam aluminum using fully recycled aluminum, and in particular, a method for preparing foam aluminum using fully recycled aluminum as raw material and controlling the viscosity of the molten metal to prepare foam aluminum with uniform bubble distribution and improve the overall production efficiency of the foam aluminum. Background Art

[0002] Since foamed aluminum has the characteristics of both metal and bubbles, and has the advantages of light weight, thermal insulation, electromagnetic shielding, high impact absorption, high temperature resistance, strong fire resistance, and high corrosion resistance, it is widely used in the construction, aerospace and other industries. In addition, since the aluminum smelting industry will produce a large amount of waste aluminum, aluminum alloy, and aluminum slag products, and these aluminum products will cause environmental pollution and harm to the human body if they are not properly recycled, many industries want to recycle these recycled aluminum and process them into foamed aluminum to improve the manufacturing and utilization efficiency of recycled aluminum and foamed aluminum.

[0003] At present, the preparation methods of foam aluminum can be mainly divided into direct blowing method and melt foaming method; the direct blowing method refers to a method of producing foam material by introducing gas into a metal melt, which has the advantages of low cost and large-scale continuous production. However, during the cooling process of molten foam aluminum, the viscosity of the molten soup is not effectively controlled, which will cause liquid separation in the preparation process of foam aluminum. The liquid separation phenomenon will cause the liquid in the flow channel of the foam aluminum to flow downward along the direction of gravity and gather, resulting in inconsistent wall thickness and seriously uneven pore size of the foam aluminum in the foam collection area, and even structural problems such as the rupture of the foam above and the accumulation of a large amount of aluminum alloy at the bottom, which seriously affect the properties, yield and preparation efficiency of the foam aluminum product.

[0004] In order to solve the above shortcomings, some industry players have developed and researched a variety of different methods for preparing foamed aluminum (such as: announcements CN207159326, CN109536766, US6984356, TW I756955, etc.), the above-mentioned methods for preparing foamed aluminum are still based on the blowing method or the melt foaming method; in terms of the melt foaming method, a foaming agent is added to make the molten soup foam, and since recycled aluminum contains a variety of substances, these substances can easily react chemically with the foaming agent, thereby affecting the generation efficiency of foamed aluminum, so the melt foaming method can only use pure aluminum as the molten soup for foaming; and in terms of the direct gas injection method, since the viscosity of the recycled aluminum molten soup is different, the position, size and thickness of the foam are different, resulting in poor foaming molding efficiency and low yield; and although some industries control the viscosity of the aluminum soup by adding a thickening agent, the thickening agent can only be added when the raw material is pure aluminum soup; therefore, how to provide a smooth formation of foamed aluminum using recycled aluminum as a raw material is indeed a problem that the current industry urgently needs to solve. Summary of the invention

[0005] The main technical problem to be solved by the present invention is to overcome the above-mentioned defects of the prior art and provide a manufacturing method for preparing foamed aluminum using fully recycled aluminum, which uses fully recycled aluminum as raw material and controls the viscosity of the molten metal to prepare uniformly distributed bubbles and improve the overall production efficiency of foamed aluminum.

[0006] The technical solution adopted by the present invention to solve its technical problem is:

[0007] A method for preparing foamed aluminum using fully recycled aluminum comprises the following steps:

[0008] Smelting: All recycled aluminum is melted at high temperature to form aluminum melt, and the aluminum melt is stirred to form a uniform state. The working temperature of the aluminum melt is controlled in its semi-solid temperature range to maintain the semi-solid aluminum melt state.

[0009] Aluminum slag grinding: Grind the recycled aluminum slag into aluminum slag powder, so that the particle size of the ground aluminum slag powder is 10-100μm;

[0010] Viscosity control: the ground aluminum slag powder is added into the semi-solid aluminum melt and stirred continuously, and the viscosity of the semi-solid aluminum melt is measured to control the viscosity of the semi-solid aluminum melt to be 1-3 mPa.s;

[0011] Gas injection foaming: injecting gas into the semi-solid aluminum melt from below at a gas flow rate of more than 10 ml / min, and by continuous stirring, the gas injected into the semi-solid aluminum melt can be evenly distributed in the semi-solid aluminum melt to form a foamed aluminum melt;

[0012] Cooling forming: After the above-mentioned foamed aluminum melt containing gas foam is cooled, foamed aluminum is formed;

[0013] By means of the above method, a method for manufacturing foam aluminum is provided, which uses fully recycled aluminum as raw material and controls the viscosity of the molten metal to prepare foam aluminum with uniform bubble distribution and improve the overall production efficiency of foam aluminum.

[0014] The beneficial effects of the present invention are that it uses fully recycled aluminum as raw material and controls the viscosity of the molten metal to prepare uniformly distributed bubbles and improve the overall production efficiency of foamed aluminum. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0016] Figure 1 It is a process step diagram of the present invention.

[0017] Figure 2 It is a cross-sectional view of the finished foam aluminum product formed by the present invention. DETAILED DESCRIPTION

[0018] Regarding the technical means and structures used by the present invention to achieve the purpose, Figure 1 to Figure 2 The embodiment shown is described in detail as follows:

[0019] like Figure 1 As shown, the method for preparing foamed aluminum using fully recycled aluminum of the present invention comprises the following steps:

[0020] Melting: All recycled aluminum is melted at high temperature to form aluminum melt, and the aluminum melt is stirred to form a uniform state. The working temperature of the aluminum melt is controlled within its semi-solid temperature range (e.g. 680℃~800℃) to maintain the semi-solid aluminum melt state.

[0021] Aluminum slag grinding: Grind the recycled aluminum slag into aluminum slag powder, so that the particle size of the ground aluminum slag powder is 10-100μm; the composition and weight percentage of the recycled aluminum slag are: aluminum oxide (Al2O3) ≧80%, other oxides ≦15%, aluminum (Al) ≦3%, aluminum nitride (AlN) ≦2%, and the ground aluminum slag powder is preferably irregular polygonal in shape.

[0022] Viscosity control: Maintain the high working temperature of the semi-solid aluminum melt (e.g., 680°C to 800°C), then add the ground aluminum slag powder into the semi-solid aluminum melt and stir evenly, and measure the viscosity of the semi-solid aluminum melt to control the viscosity of the semi-solid aluminum melt to be 1 to 3 mPa.s.

[0023] Gas injection foaming: Inject gas into the semi-solid aluminum melt from below at a gas flow rate of more than 10 ml / min (sccm), and by continuous stirring, the gas injected into the semi-solid aluminum melt can be evenly distributed in the semi-solid aluminum melt to form a foamed aluminum melt.

[0024] Cooling molding: After the above-mentioned foam aluminum melt containing gas foam is cooled, foam aluminum (i.e., porous aluminum material) is formed.

[0025] As mentioned above, the gas injected in the gas injection and foaming step can be nitrogen (N2), air (Air), argon (Ar) and other gases.

[0026] Through the above steps, since the present invention uses fully recycled aluminum as raw material, which contains aluminum alloy waste in addition to pure aluminum metal, the fully recycled aluminum is melted at high temperature to form a semi-solid aluminum melt, and then ground aluminum slag powder is added and stirred evenly to make the aluminum slag powder evenly distributed in the semi-solid aluminum melt, so as to control the viscosity of the semi-solid aluminum melt to be between 1 and 3 MPa.s; at this time, after the gas is injected from the bottom of the semi-solid aluminum melt, since the viscosity of the semi-solid aluminum melt is 1 to 3 MPa.s, and the semi-solid aluminum melt contains aluminum alloy waste and aluminum slag powder, the injected gas can be evenly distributed in the semi-solid aluminum melt to form a semi-solid aluminum melt containing gas foam, and the semi-solid aluminum melt is in sufficient contact with the gas foam to form a foamed aluminum melt; then, when the foamed aluminum melt containing gas foam is cooled, it is formed into foamed aluminum (i.e., porous aluminum material).

[0027] And as Figure 2 As shown, it is a cross-sectional view of foamed aluminum formed by foaming fully recycled aluminum by controlling the viscosity of semi-solid aluminum melt at different times using the manufacturing method of the present invention. As can be seen from the accompanying figure, the foamed aluminum made by the manufacturing method of the present invention obviously has better foaming thickness and density by controlling the viscosity of the semi-solid aluminum melt to 2.5-3 MPa.s.

[0028] Therefore, from the above description, it can be seen that the present invention has the following advantages:

[0029] (1) Since the present invention uses fully recycled aluminum as the foaming raw material, and the present invention uses gas injection to foam the fully recycled aluminum without adding a foaming agent, the present invention can effectively improve the recyclability of the recycled aluminum, reduce the preparation cost, and improve the overall production efficiency of foamed aluminum.

[0030] (ii) Since the present invention adjusts and controls the viscosity of the semi-solid aluminum melt to be between 1 and 3 MPa.s by adding aluminum slag powder into the semi-solid aluminum melt, it can provide the optimal viscosity for gas foam foaming, so that the gas foam can be evenly distributed in the semi-solid aluminum melt to form a foamed aluminum melt; thereby providing a foamed aluminum with a relatively uniform thickness and density.

[0031] (iii) Furthermore, since the viscosity of the semi-solid aluminum melt is controlled within the range of 1 to 3 MPa.s, the present invention can avoid the situation that the gas foam of the semi-solid aluminum melt cannot be evenly distributed and is difficult to foam due to the high viscosity; it can also avoid the situation that the semi-solid aluminum melt foams too early due to the low viscosity, resulting in too thin a thickness or poor foaming efficiency.

[0032] (iv) Furthermore, since the present invention adopts the gas injection foaming method and is limited by the semi-solid aluminum melt with a viscosity between 1 and 3 MPa.s, the size of the injected gas foam can be effectively adjusted and controlled, so that the size of the holes in the formed foamed aluminum is more uniform, thereby improving the utilization of the foamed aluminum.

[0033] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any simple modification, equivalent changes and modifications made to the above embodiments based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A method for preparing foamed aluminum using fully recycled aluminum, characterized in that: It includes the following steps: Melting: Melt the fully recycled aluminum at high temperature to form aluminum melt, stir the aluminum melt to form a uniform state, and control the working temperature of the aluminum melt in its semi-solid temperature range to maintain the semi-solid aluminum melt state; Aluminum slag grinding: Grind the recycled aluminum slag into aluminum slag powder; Viscosity control: put the ground aluminum slag powder into the semi-solid aluminum melt and stir it continuously, measure the viscosity of the semi-solid aluminum melt, and control the viscosity of the semi-solid aluminum melt to be 1-3mPa.s; Gas injection foaming: injecting gas into the semi-solid aluminum melt from below at a gas flow rate of more than 10 ml / min, and by continuous stirring, the gas injected into the semi-solid aluminum melt can be evenly distributed in the semi-solid aluminum melt to form a foamed aluminum melt; Cooling molding: After the above-mentioned foam aluminum melt containing gas foam is cooled, foam aluminum is formed.

2. The method for preparing foamed aluminum from fully recycled aluminum according to claim 1, characterized in that: The semi-solid temperature range of the semi-solid aluminum melt is 680°C to 800°C.

3. The method for preparing foamed aluminum from fully recycled aluminum according to claim 1, characterized in that: The composition and weight percentage of the recycled aluminum slag are: aluminum oxide (Al2O3) ≧80%, other oxides ≦15%, aluminum (Al) ≦3%, and aluminum nitride (AlN) ≦2%.

4. The method for preparing foamed aluminum from fully recycled aluminum according to claim 1, characterized in that: The particle size of the ground aluminum slag powder is 10 to 100 μm.

5. The method for preparing foamed aluminum from fully recycled aluminum according to claim 1, characterized in that: The viscosity of the semi-solid aluminum melt is optimally 2.5 to 3 MPa.s.

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