A device and method for online vacuum degassing of molten aluminum

Abstract

The present invention discloses a device and method for online vacuum degassing of aluminum liquid, the device comprises a vacuum furnace, a double-chamber tank and a vacuum pump; two recessed parts are provided at the bottom of the vacuum furnace, which are respectively connected to a riser and a downcomer; the two recessed parts are provided with air-permeable bricks along the periphery of the riser and the downcomer; an aluminum liquid flow trough inlet and an aluminum liquid flow trough outlet are respectively provided on both sides of the double-chamber tank; a partition is provided in the middle of the double-chamber tank, and the partition separates the double-chamber tank into an inlet tank and an outlet tank; the aluminum liquid level on one side of the riser in the double-chamber tank is higher than that on one side of the downcomer; the vacuum furnace is mounted on the double-chamber tank and can move in a vertical direction, and the riser and the downcomer extend into the inlet tank and the outlet tank respectively; the vacuum pump is arranged on the top of the vacuum furnace. The present invention separates the vacuum furnace from the double-chamber tank, adjusts the depth of the aluminum liquid molten pool in the vacuum chamber by adjusting the relative height and vacuum degree of the vacuum furnace, and controls the aluminum liquid flow by spraying inert gas to the air-permeable bricks, so that the degassing is stable and efficient.

Description

Technical Field

[0001] The invention relates to the technical field of material metallurgy, and in particular to a device and method for online vacuum degassing of molten aluminum. Background Art

[0002] The gas element in aluminum liquid is mainly hydrogen, and its content is generally greater than 0.35ml / 100g. It precipitates and forms bubbles during the solidification process of aluminum liquid. Once captured by the solidification front, it will form pinholes, pores, looseness and other casting defects in the ingot, resulting in the scrapping of the ingot or subsequent processing defects. It is reported that the casting waste caused directly or indirectly by the excessive hydrogen concentration in aluminum liquid accounts for more than 40% of the total waste. With the wider application range of aluminum alloy products, the requirements for the density of the internal structure of aluminum alloy ingots are also getting higher and higher. Reducing the hydrogen content in aluminum liquid plays an important role in improving the quality of aluminum alloy ingots. In order to reduce the hydrogen content in molten aluminum, domestic aluminum processing companies currently use a degassing device that uses a rotary inert gas spray. This type of traditional rotary spray degassing device places a graphite rotor in the trough aluminum liquid to spray inert gas. The rotating graphite rotor breaks up the bubbles to form small bubbles, increasing the contact area between the inert gas and the aluminum liquid and the time for the bubbles to float. Since the hydrogen partial pressure of the inert bubbles is low, the hydrogen atoms in the aluminum liquid form hydrogen molecules and enter the inert bubbles. The bubbles float up and are removed to achieve the purpose of dehydrogenation. However, domestic companies still need to mix a small amount of toxic gas chlorine into the inert gas to ensure a high degassing efficiency when producing high-end aluminum alloys. There are great safety hazards and environmental pollution risks. The hydrogen content of the aluminum liquid after degassing mainly depends on the hydrogen concentration of the incoming aluminum liquid before degassing. The degassing efficiency of the aluminum liquid is unstable. Therefore, the incoming aluminum liquid must be pretreated before online degassing, which increases the process cost and production cycle. Summary of the invention

[0003] The purpose of the present invention is to solve the problems of "unstable degassing effect" and "toxic chlorine gas spraying when producing high-end aluminum alloy" in the existing aluminum liquid degassing technology, and to provide a stable and efficient aluminum liquid online vacuum degassing device and method, the purpose of which is to reduce the hydrogen content in the aluminum liquid before casting, thereby improving the internal structure quality of the aluminum alloy ingot.

[0004] To solve the above problems, the present invention adopts the following technical solutions:

[0005] A device for online vacuum degassing of molten aluminum comprises a vacuum furnace, a double-chamber tank and a vacuum pump; two recessed parts are arranged at the bottom of the vacuum furnace; the two recessed parts are respectively connected to a riser for the aluminum liquid to flow into the vacuum furnace and a downcomer for the aluminum liquid to flow out of the vacuum furnace; the two recessed parts are provided with air-permeable bricks along the circumference of the riser and the downcomer, and the air-permeable bricks are used to provide inert gas; an aluminum liquid flow trough inlet and an aluminum liquid flow trough outlet are respectively arranged on both sides of the double-chamber tank; a partition is arranged in the middle of the double-chamber tank, and the partition divides the double-chamber tank into an inlet trough and an outlet trough; the aluminum liquid level on the side of the riser in the double-chamber tank is higher than the aluminum liquid level on the side of the downcomer; the vacuum furnace is mounted on the double-chamber tank and can move away from or close to the double-chamber tank in a vertical direction, and the lower ends of the riser and the downcomer extend into the inlet trough and the outlet trough respectively; the vacuum pump is arranged on the top of the vacuum furnace.

[0006] Furthermore, the vacuum furnace comprises an upper furnace body and a lower furnace body, and a sealing ring is provided at the connection between the upper furnace body and the lower furnace body.

[0007] Furthermore, the vacuum furnace is also provided with a gas burner.

[0008] Furthermore, the top of the vacuum furnace is also connected to an exhaust pipe, and a hydrogen detector is provided on the exhaust pipe.

[0009] Furthermore, the permeable bricks are connected to an inert gas supply system. The gas flow rate of the permeable bricks on the periphery of the riser is greater than the gas flow rate of the permeable bricks on the periphery of the downcomer.

[0010] Furthermore, the outer side wall of the vacuum furnace is provided with a height adjustment frame for adjusting the height of the vacuum furnace.

[0011] Furthermore, the partition is made of refractory material.

[0012] Another object of the present invention is also to provide a degassing method for an online vacuum degassing device for molten aluminum, which comprises the following steps:

[0013] S1: Inject aluminum liquid into the double-chamber tank from the aluminum liquid flow trough inlet, lower the vacuum furnace so that the riser and downcomer of the vacuum furnace are immersed in the aluminum liquid in the double-chamber tank respectively, turn on the vacuum pump to evacuate the vacuum furnace so that the air pressure in the vacuum furnace is lower than the external pressure of the vacuum furnace. The aluminum liquid enters the vacuum furnace under the action of the air pressure difference inside and outside the vacuum furnace and starts to be degassed;

[0014] S2: During the degassing process of the aluminum liquid, a small amount of inert gas is sprayed through the permeable bricks. The gas sprayed toward the permeable bricks surrounding the riser and downcomers is greater than the gas flow rate of the permeable bricks surrounding the downcomers, so as to keep the aluminum liquid level on the riser side of the double-chamber tank higher than that on the downcomer side, keep the liquid level stable and the height of the middle partition of the double-chamber tank higher than the liquid levels on both sides of the double-chamber tank. The aluminum liquid on the inlet side of the aluminum liquid flow channel of the double-chamber tank flows into the vacuum furnace through the riser. The aluminum liquid completes the degassing process in the vacuum furnace. The aluminum liquid flowing through the vacuum furnace flows into the other side of the double-chamber tank through the downcomer and flows out through the aluminum liquid flow channel outlet.

[0015] During the degassing process of the aluminum liquid, the gas pressure of the vacuum furnace is controlled to be 100-10000 Pa by a vacuum pump.

[0016] Wherein, during the degassing process of the aluminum liquid, the height from the bottom of the air-permeable brick to the aluminum liquid level in the vacuum furnace is 0.1 to 0.5 m.

[0017] The aluminum liquid is heated by a gas nozzle to maintain the temperature of the aluminum liquid flowing out of the double-chamber tank from one side of the downcomer at 700-720°C.

[0018] Compared with the prior art, the present invention has the following beneficial effects:

[0019] The present invention utilizes the hydrogen atoms dissolved in the aluminum liquid to precipitate and form hydrogen bubbles when the aluminum liquid flows through the vacuum chamber, and the hydrogen bubbles float up and are removed, thereby achieving the purpose of degassing. The present invention can adjust the depth of the aluminum liquid molten pool in the vacuum chamber by adjusting the relative height and vacuum degree of the vacuum furnace by separately arranging the vacuum furnace and the vacuum degree, and control the flow rate of the aluminum liquid by spraying a small amount of inert gas to the air-permeable bricks, thereby ensuring that the entire degassing process is stable and the aluminum liquid has high degassing efficiency. The present invention has a high degassing efficiency of aluminum liquid under the condition of only spraying inert gas, and the hydrogen concentration of the aluminum liquid after degassing is not affected by the hydrogen concentration of the incoming aluminum liquid, which solves the problems of "unstable degassing effect" and "spraying toxic chlorine when producing high-end aluminum alloys" in the existing degassing methods and devices. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] Figure 1 It is a structural schematic diagram of the online vacuum degassing device for aluminum liquid of the present invention;

[0021] In the figure, 1-vacuum furnace, 11-upper furnace body, 12-lower furnace body, 13-depression, 14-liquid rising pipe, 15-liquid downcomer, 16-air permeable brick, 2-double chamber tank, 21-aluminum liquid, 22-aluminum liquid flow trough inlet, 23-aluminum liquid flow trough outlet, 3-sealing ring, 4-gas burner, 5, vacuum pump, 6-hydrogen meter, 7-partition, 8-exhaust pipe. DETAILED DESCRIPTION

[0022] The present invention will be further described below in conjunction with the accompanying drawings and embodiments.

[0023] Example 1

[0024] like Figure 1 As shown, an online vacuum degassing device for aluminum liquid comprises a vacuum furnace 1, a double-chamber tank 2 and a vacuum pump 5; two recessed parts 13 are provided at the bottom of the vacuum furnace 1; the two recessed parts 13 are respectively connected to a liquid riser 14 for aluminum liquid 21 to flow into the vacuum furnace 1 and a liquid downcomer 15 for aluminum liquid 21 to flow out of the vacuum furnace 1; the two recessed parts 13 are provided with air-permeable bricks 16 along the periphery of the liquid riser 14 and the liquid downcomer 15, and the air-permeable bricks 16 are used to provide inert gas; aluminum liquid flow channel inlets 2 are respectively provided on both sides of the double-chamber tank 2. 2 and an aluminum liquid flow trough outlet 23; a partition 7 is arranged in the middle of the double-chamber tank 2, and the partition 7 divides the double-chamber tank 2 into an inlet tank and an outlet tank; the liquid level of the aluminum liquid 21 on one side of the riser 14 in the double-chamber tank 2 is higher than the horizontal height of the aluminum liquid 21 on one side of the downcomer 15; the vacuum furnace 1 is mounted on the double-chamber tank 2 and can move away from or approach the double-chamber tank 2 in the vertical direction, and the lower ends of the riser 14 and the downcomer 15 extend into the inlet tank and the outlet tank respectively; a vacuum pump 5 is arranged on the top of the vacuum furnace 1.

[0025] Preferably, in the present embodiment, the vacuum furnace 1 comprises an upper furnace body 11 and a lower furnace body 12, and a sealing ring 3 is provided at the connection between the upper furnace body 11 and the lower furnace body 12; the inner wall of the vacuum furnace 1 is generally a refractory material, and the lower half of the vacuum furnace 1 is generally susceptible to corrosion by the aluminum liquid 21. The present invention splits the vacuum furnace 1 into an upper furnace body 11 and a lower furnace body 12, which is convenient for disassembly and maintenance. A sealing ring 3 is provided in the middle, which can better seal the vacuum furnace 1 and prevent air from entering the vacuum furnace 1 after vacuuming.

[0026] Preferably, in this embodiment, a gas burner 4 is further provided in the vacuum furnace 1, and more specifically, the gas burner 4 is provided in the upper furnace body 11 of the vacuum furnace 1. The gas burner 4 serves as a heating device for the aluminum liquid 21 to ensure the temperature of the aluminum liquid 21.

[0027] Preferably, in this embodiment, the top of the vacuum furnace 1 is further connected to an exhaust pipe 8, and a hydrogen detector 6 is provided on the exhaust pipe 8. The hydrogen detector 6 can be turned on throughout the degassing process of the aluminum liquid 21 to monitor the hydrogen discharge in real time.

[0028] Preferably, in this embodiment, the device for online vacuum degassing of the aluminum liquid further includes a vacuum pump 5, which is arranged on the top of the vacuum furnace 1. The vacuum pump 5 can evacuate the vacuum furnace 1, and the vacuum degree required by the vacuum furnace 1 can be adjusted by the vacuum pump 5 to ensure that the degassing of the aluminum liquid 21 is stable and efficient.

[0029] Preferably, in this embodiment, the air brick 16 is connected to the inert gas supply system, and the gas supply system is connected to the bottom of the air brick 16 through a pipeline. When the gas is introduced into the bottom of the air brick 16, the inert gas can take away the hydrogen in the aluminum liquid 21 on the one hand, and on the other hand, the flow rate of the aluminum liquid 21 can be regulated by regulating the air flow difference of the inert gas on both sides of the liquid inlet pipe and the liquid riser 14. Specifically, the gas flow rate sprayed to the air brick 16 on the side of the liquid riser 14 is greater than the gas flow rate sprayed to the air brick 16 on the side of the liquid downcomer 15, so as to promote the circulation of aluminum liquid.

[0030] Preferably, in this embodiment, the partition 7 is made of a refractory material.

[0031] Preferably, in the present embodiment, the outer wall of the vacuum furnace 1 is provided with a height adjustment frame for adjusting the height of the vacuum furnace 1. In the present embodiment, the vacuum furnace 1 and the double-chamber tank 2 are designed separately, and the height of the vacuum furnace 1 is adjusted by the height adjustment frame, that is, the height of the vacuum furnace 1 relative to the double-chamber tank 2 is adjusted by the height adjustment frame to adjust the liquid level of the aluminum liquid 21 in the vacuum furnace 1. The height adjustment frame includes a circular ring base, on which a control box is provided, and a plurality of electric telescopic rods are vertically provided on the top of the circular ring base along the circumferential direction, and the electric telescopic rods are fixedly connected to the vacuum furnace 1. Of course, in other embodiments, any height adjustment structure that can achieve height adjustment of the vacuum furnace 1 is acceptable.

[0032] The reason why the present invention can realize that the aluminum liquid 21 enters the vacuum furnace 1 from the riser 14 and then flows out from the downcomer 15 when the vacuum chamber and the double-chamber tank 2 are separated, and can circulate is because the vacuum furnace 1 is evacuated and an inert gas is introduced into the air-permeable brick 16. After evacuation, under the action of the pressure difference between the inside and outside of the vacuum furnace 1, the aluminum liquid 21 enters the vacuum furnace 1 from the double-chamber tank 2, and the liquid level of the aluminum liquid 21 on the side of the riser 14 in the double-chamber tank 2 is higher than the level of the aluminum liquid 21 on the side of the downcomer 15, which can form a siphon effect. The siphon effect provides power for the circulation of the aluminum liquid 21, and the inert gas is blown into the bottom of the air-permeable brick 16. The inert gas is connected to the air-permeable brick 1 through a pipeline. 6, inert gas is sprayed from the bottom of the permeable brick 16 into the aluminum liquid 21, and floats up to the liquid surface under the action of buoyancy. In addition to taking away hydrogen, it also drives the aluminum liquid 21 in the riser 14 and the downcomer 15 to float upward. The gas flow rate sprayed by the permeable brick 16 surrounding the riser 14 is greater than the gas flow rate sprayed by the permeable brick 16 surrounding the downcomer 15. Since the gas flow rate on one side of the riser 14 is larger, the riser 14 side drives the aluminum liquid 21 to flow more, resulting in a higher liquid level in the vacuum furnace 1 on the riser 14 side, forming a liquid level potential difference. Under the action of the liquid level potential difference, the aluminum liquid 21 is easy to flow, so the aluminum liquid 21 can circulate at a vacuum rate and be degassed.

[0033] The present invention adjusts the depth of the aluminum liquid 21 molten pool in the vacuum chamber by adjusting the relative height and vacuum degree of the vacuum furnace 1, and adjusts the flow rate of the aluminum liquid 21 by spraying a small amount of inert gas to the air-permeable bricks 16, so as to keep the gas flow rate sprayed by the air-permeable bricks 16 around the riser 14 greater than the gas flow rate sprayed by the air-permeable bricks 16 around the downcomer 15, so as to ensure that the liquid level is stable and the height of the partition plate 7 in the middle of the double-chamber tank 2 is higher than the liquid level on both sides of the double-chamber tank 2, and keep the liquid level of the aluminum liquid 21 on one side of the riser 14 in the double-chamber tank 2 higher than the one side of the downcomer 15, so that the whole degassing process is stable and the degassing efficiency of the aluminum liquid 21 is high. At the same time, under the premise of ensuring that the gas flow rate sprayed by the air-permeable bricks 16 around the riser 14 is greater than the gas flow rate sprayed by the air-permeable bricks 16 around the downcomer 15, the overall flow rate and velocity of the aluminum liquid 21 can be adjusted by adjusting the spraying amount of the inert gas.

[0034] The above-mentioned aluminum liquid online vacuum degassing device is used for degassing, and the degassing method includes the following steps:

[0035] S1: injecting aluminum liquid 21 into the double-chamber tank 2 from the aluminum liquid flow trough inlet 22, lowering the vacuum furnace 1 so that the riser 14 and the downcomer 15 of the vacuum furnace 1 are respectively immersed in the aluminum liquid 21 in the double-chamber tank 2, turning on the vacuum pump 5 to evacuate the vacuum furnace 1 so that the air pressure in the vacuum furnace 1 is lower than the external pressure of the vacuum furnace 1, and the aluminum liquid 21 enters the vacuum furnace 1 under the action of the air pressure difference between the inside and outside of the vacuum furnace 1 and starts to be degassed;

[0036] S2: During the degassing process of the aluminum liquid 21, a small amount of inert gas is sprayed through the air bricks 16, and the gas flow rate of the air bricks 16 sprayed around the riser 14 and the downcomer 15 is greater than the gas flow rate of the air bricks 16 sprayed around the downcomer 15, so as to keep the liquid level of the aluminum liquid 21 on the side of the riser 14 in the double-chamber tank 2 higher than the side of the downcomer 15, keep the liquid level stable and the height of the middle partition 7 of the double-chamber tank 2 higher than the liquid level on both sides of the double-chamber tank 2, and the aluminum liquid 21 on the side of the aluminum liquid flow channel inlet 22 of the double-chamber tank 2 flows into the vacuum furnace 1 through the riser 14, and the aluminum liquid 21 completes the degassing process in the vacuum furnace 1, and the aluminum liquid 21 flowing through the vacuum furnace 1 flows into the other side of the double-chamber tank 2 through the downcomer 15, and flows out through the aluminum liquid flow channel outlet 23. During the whole degassing process, the air pressure of the vacuum furnace 1 is controlled to be 8000Pa by the vacuum pump 5. The height from the bottom of the air-permeable brick 16 to the liquid level of the aluminum liquid 21 in the vacuum furnace 1 is 0.3 m. The aluminum liquid 21 is heated by a gas nozzle to maintain the temperature of the aluminum liquid 21 flowing out of the double chamber tank 2 from one side of the downcomer 15 at 710°C.

[0037] Example 2

[0038] The aluminum liquid online vacuum degassing device of Example 1 is used for degassing, and the degassing method comprises the following steps:

[0039] S1: injecting aluminum liquid 21 into the double-chamber tank 2 from the aluminum liquid flow trough inlet 22, lowering the vacuum furnace 1 so that the riser 14 and the downcomer 15 of the vacuum furnace 1 are respectively immersed in the aluminum liquid 21 in the double-chamber tank 2, turning on the vacuum pump 5 to evacuate the vacuum furnace 1 so that the air pressure in the vacuum furnace 1 is lower than the external pressure of the vacuum furnace 1, and the aluminum liquid 21 enters the vacuum furnace 1 under the action of the air pressure difference between the inside and outside of the vacuum furnace 1 and starts to be degassed;

[0040] S2: During the degassing process of the aluminum liquid 21, a small amount of inert gas is sprayed through the air bricks 16, and the gas flow rate of the gas blown to the air bricks 16 around the riser 14 and the downcomer 15 is greater than the gas flow rate of the gas blown by the air bricks 16 around the downcomer 15, so as to keep the liquid level of the aluminum liquid 21 on the side of the riser 14 in the double-chamber tank 2 higher than the side of the downcomer 15, keep the liquid level stable and the height of the middle partition 7 of the double-chamber tank 2 higher than the liquid level on both sides of the double-chamber tank 2, and the aluminum liquid 21 on the side of the aluminum liquid flow channel inlet 22 of the double-chamber tank 2 flows into the vacuum furnace 1 through the riser 14, and the aluminum liquid 21 completes the degassing process in the vacuum furnace 1, and the aluminum liquid 21 flowing through the vacuum furnace 1 flows into the other side of the double-chamber tank 2 through the downcomer 15, and flows out through the aluminum liquid flow channel outlet 23. During the whole degassing process, the air pressure of the vacuum furnace 1 is controlled to be 10000Pa by the vacuum pump 5. The height from the bottom of the air-permeable brick 16 to the liquid level of the aluminum liquid 21 in the vacuum furnace 1 is 0.1 m. The aluminum liquid 21 is heated by a gas nozzle to maintain the temperature of the aluminum liquid 21 flowing out of the double-chamber tank 2 from one side of the downcomer 15 at 720°C.

[0041] Example 3

[0042] The aluminum liquid online vacuum degassing device of Example 1 is used for degassing, and the degassing method comprises the following steps:

[0043] S1: injecting aluminum liquid 21 into the double-chamber tank 2 from the aluminum liquid flow trough inlet 22, lowering the vacuum furnace 1 so that the riser 14 and the downcomer 15 of the vacuum furnace 1 are respectively immersed in the aluminum liquid 21 in the double-chamber tank 2, turning on the vacuum pump 5 to evacuate the vacuum furnace 1 so that the air pressure in the vacuum furnace 1 is lower than the external pressure of the vacuum furnace 1, and the aluminum liquid 21 enters the vacuum furnace 1 under the action of the air pressure difference between the inside and outside of the vacuum furnace 1 and starts to be degassed;

[0044] S2: During the degassing process of the aluminum liquid 21, a small amount of inert gas is sprayed through the air bricks 16, and the gas flow rate of the gas blown to the air bricks 16 around the riser 14 and the downcomer 15 is greater than the gas flow rate of the gas blown by the air bricks 16 around the downcomer 15, so as to keep the liquid level of the aluminum liquid 21 on the side of the riser 14 in the double-chamber tank 2 higher than the side of the downcomer 15, keep the liquid level stable and the height of the middle partition 7 of the double-chamber tank 2 higher than the liquid level on both sides of the double-chamber tank 2, and the aluminum liquid 21 on the side of the aluminum liquid flow channel inlet 22 of the double-chamber tank 2 flows into the vacuum furnace 1 through the riser 14, and the aluminum liquid 21 completes the degassing process in the vacuum furnace 1, and the aluminum liquid 21 flowing through the vacuum furnace 1 flows into the other side of the double-chamber tank 2 through the downcomer 15, and flows out through the aluminum liquid flow channel outlet 23. During the whole degassing process, the air pressure of the vacuum furnace 1 is controlled to be 100Pa by the vacuum pump 5. The height from the bottom of the air-permeable brick 16 to the liquid level of the aluminum liquid 21 in the vacuum furnace 1 is 0.5 m. The aluminum liquid 21 is heated by a gas nozzle to maintain the temperature of the aluminum liquid 21 flowing out of the double chamber tank 2 from one side of the downcomer 15 at 700°C.

[0045] Degassing effect:

[0046] 1. After the degassing is started, the change in the hydrogen concentration of the aluminum liquid detected by the hydrogen detector is as follows in Table 1 after an interval of 1 to 2 hours:

[0047] Table 1

[0048]

[0049] 2. After degassing begins, the hydrogen concentration of the incoming aluminum liquid (i.e. the hydrogen concentration of the aluminum liquid at the entrance of the aluminum liquid flow trough) is tested every 1 to 2 hours. The results are shown in Table 2:

[0050] Table 2

[0051]

[0052]

[0053] 3. After degassing begins, the concentration of hydrogen in the aluminum liquid after degassing (i.e. the concentration of hydrogen in the aluminum liquid at the outlet of the aluminum liquid flow tank) is tested every 1 to 2 hours. The results are shown in Table 3 below:

[0054] Table 3

[0055]

[0056] It can be seen from Table 1 and Table 3 above that the aluminum liquid online degassing method of the present application is highly efficient and stable. It can be seen from Table 2 and Table 3 that no matter how much the hydrogen concentration of the incoming aluminum liquid is, after dehydrogenation by the aluminum liquid online degassing method of the present application, the aluminum liquid hydrogen concentration is within the qualified range, and the dehydrogenation effect of the present invention is good.

[0057] The above description is a detailed description of the preferred feasible embodiments of the present invention, but the embodiments are not intended to limit the scope of the patent application of the present invention. All equivalent changes or modified changes completed under the technical spirit suggested by the present invention should fall within the patent scope covered by the present invention.

Claims

1. A device for online vacuum degassing of molten aluminum, characterized in that: It comprises a vacuum furnace, a double-chamber tank and a vacuum pump; two recessed parts are arranged at the bottom of the vacuum furnace; the two recessed parts are respectively connected to a liquid riser for aluminum liquid to flow into the vacuum furnace and a liquid downcomer for aluminum liquid to flow out of the vacuum furnace; the two recessed parts are provided with air-permeable bricks along the periphery of the liquid riser and the liquid downcomer, and the air-permeable bricks are used to provide inert gas; an aluminum liquid flow trough inlet and an aluminum liquid flow trough outlet are respectively arranged on both sides of the double-chamber tank; a partition is arranged in the middle of the double-chamber tank, and the partition divides the double-chamber tank into a liquid inlet trough and a liquid outlet trough; the liquid level of aluminum liquid in the vacuum furnace on one side of the liquid riser is higher than that of the liquid downcomer The height of the aluminum liquid level in the vacuum furnace on one side; the vacuum furnace is mounted on the double-chamber tank and can move away from or close to the double-chamber tank in the vertical direction, and the lower ends of the riser and the downcomer extend into the liquid inlet and outlet tanks respectively; the vacuum pump is arranged on the top of the vacuum furnace; the air-permeable bricks are connected to the inert gas supply system, and the gas flow rate of the air-permeable bricks on the side of the riser is greater than the gas flow rate of the air-permeable bricks on the side of the downcomer; the outer wall of the vacuum furnace is provided with a height adjustment frame for adjusting the height of the vacuum furnace; the vacuum furnace is also provided with a gas burner.

2. The aluminum liquid online vacuum degassing device according to claim 1, characterized in that: The vacuum furnace comprises an upper furnace body and a lower furnace body, and a sealing ring is arranged at the connection between the upper furnace body and the lower furnace body.

3. The aluminum liquid online vacuum degassing device according to claim 1, characterized in that: The top of the vacuum furnace is also connected to an exhaust pipe, and a hydrogen detector is arranged on the exhaust pipe.

4. A degassing method using the aluminum liquid online vacuum degassing device according to any one of claims 1 to 3, characterized in that: It includes the following steps: S1: Inject aluminum liquid into the double-chamber tank from the aluminum liquid flow trough inlet, lower the vacuum furnace so that the riser and downcomer of the vacuum furnace are immersed in the aluminum liquid in the double-chamber tank respectively, turn on the vacuum pump to evacuate the vacuum furnace so that the air pressure in the vacuum furnace is lower than the external pressure of the vacuum furnace. The aluminum liquid enters the vacuum furnace under the action of the air pressure difference inside and outside the vacuum furnace and starts to be degassed; S2: During the degassing process of the aluminum liquid, a small amount of inert gas is sprayed through the permeable bricks. The gas flow rate of the permeable bricks around the riser is greater than the gas flow rate of the permeable bricks around the downcomer, so as to keep the aluminum liquid level in the vacuum furnace on the riser side higher than that on the downcomer side, keep the liquid level stable and the height of the middle partition of the double-chamber tank higher than the liquid levels on both sides of the double-chamber tank. The aluminum liquid on the inlet side of the aluminum liquid flow channel of the double-chamber tank flows into the vacuum furnace through the riser. The aluminum liquid completes the degassing process in the vacuum furnace. The aluminum liquid flowing through the vacuum furnace flows into the other side of the double-chamber tank through the downcomer and flows out through the aluminum liquid flow channel outlet.

5. The method according to claim 4, characterized in that During the degassing process of the aluminum liquid, the gas pressure of the vacuum furnace is controlled to be 100~10000Pa by a vacuum pump.

6. The method according to claim 4, characterized in that During the degassing process of the aluminum liquid, the height from the bottom of the air-permeable brick to the surface of the aluminum liquid in the vacuum furnace is 0.1-0.5 m.

7. The method according to claim 4, characterized in that During the degassing process of the aluminum liquid, the aluminum liquid is heated by a gas burner to maintain the temperature of the aluminum liquid flowing out of the double-chamber tank from one side of the downcomer at 700~720℃.

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