High-efficiency low-oxidation aluminum smelting equipment

Abstract

The utility model belongs to the technical field of metal smelting, especially disclose high -efficient low oxidization's aluminium smelting equipment, including, smelting pipe: smelting pipe two open end portion fixed and oblique arrangement, electromagnetic heating system: smelting pipe is from top to bottom and divides into first electromagnetic heating system and second electromagnetic heating system, nitrogen protection system: corresponding setting in second electromagnetic heating area is inputted nitrogen gas for its protection, including nitrogen gas inlet and waste gas outlet, wherein, nitrogen gas inlet is placed in the starting end side wall of second electromagnetic heating area, and waste gas outlet is placed in the bottom side wall of smelting pipe. The aluminium smelting equipment realizes aluminium block raw material automatic sliding conveying by the design of oblique smelting pipe, and through the technology of sectional electromagnetic heating and nitrogen positive pressure protection, ensures that aluminium liquid can be isolated from oxygen in the melting stage, avoids aluminium oxidation, makes aluminium burning loss rate reduce to below 1%, significantly improves aluminium liquid cleanliness and production economy.

Description

Technical Field

[0001] This utility model belongs to the field of metal smelting technology, and specifically relates to high-efficiency, low-oxidation aluminum smelting equipment. Background Technology

[0002] In existing technologies, the traditional aluminum smelting process involves heating and melting aluminum raw materials (mainly scrap aluminum or primary aluminum ingots), refining them, adjusting their composition, and finally obtaining a liquid aluminum alloy that meets specific composition and quality requirements.

[0003] In traditional aluminum smelting processes, the heating and melting methods commonly used are natural gas heating or coal heating. However, in practical applications, natural gas heating or coal heating has the following drawbacks:

[0004] 1. Combustion requires a large amount of oxygen, which easily leads to further oxidation of the molten aluminum to form an alumina (Al2O3) slag layer. The aluminum burn-off rate is as high as 5-8%, resulting in a huge waste of aluminum raw materials.

[0005] 2. Low thermal efficiency, <40%, making it difficult to control the temperature in the combustion furnace, and the temperature is unstable;

[0006] 3. Increased impurity content in the melt leads to large fluctuations in the quality of the molten aluminum, making it difficult to guarantee quality stability.

[0007] In addition, nitrogen is used as a protective gas in many chemical fields, but its application in aluminum smelting technology is relatively limited. Firstly, the use of nitrogen increases the overall production cost. Secondly, it is difficult to precisely control the timing of nitrogen addition and the amount of nitrogen used during smelting. If the nitrogen level is too high, the oxidizing environment required for combustion will be affected, resulting in poor aluminum smelting and greatly affecting the quality of the final molten aluminum.

[0008] Therefore, it is urgent to develop a high-efficiency, low-oxidation aluminum smelting equipment that can be protected by nitrogen gas. Utility Model Content

[0009] The purpose of this utility model is to overcome the shortcomings of the prior art and specifically disclose a high-efficiency, low-oxidation aluminum smelting equipment. This aluminum smelting equipment achieves automatic sliding conveying of aluminum block raw materials by gravity through the design of inclined smelting tubes. Through segmented electromagnetic heating and nitrogen positive pressure protection technology, it ensures that oxygen can be isolated during the molten aluminum stage to avoid aluminum oxidation, thereby reducing the aluminum burn-off rate to below 1% and significantly improving the cleanliness of the molten aluminum and the economic efficiency of production.

[0010] To achieve the above-mentioned technical objectives, this utility model is implemented according to the following technical solution:

[0011] The present invention relates to a high-efficiency, low-oxidation aluminum smelting equipment, comprising:

[0012] Melting tube: The two open ends of the melting tube are fixed and arranged at an angle;

[0013] Electromagnetic heating system: The melting tube is divided into a first electromagnetic heating system and a second electromagnetic heating system from top to bottom. The first electromagnetic heating system includes a first electromagnetic heating coil wound around the outer periphery of the upper half of the melting tube, which corresponds to the first electromagnetic heating zone in which the aluminum block is preheated in solid state in the inner cavity of the upper half of the melting tube; and a second electromagnetic heating coil wound around the outer periphery of the lower half of the melting tube, which corresponds to the second electromagnetic heating zone in which the liquid aluminum is melted at high temperature in the inner cavity of the lower half of the melting tube.

[0014] Nitrogen protection system: Nitrogen is introduced into the second electromagnetic heating zone. It includes a nitrogen inlet and an exhaust outlet. The nitrogen inlet is located on the side wall at the beginning of the second electromagnetic heating zone, and the exhaust outlet is located on the bottom side wall of the melting tube.

[0015] As a further improvement to the above technology, the diameter Φ of the melting tube is 300mm-500mm, its inclination angle A ranges from 30° to 60°, and its length is 2m-12m.

[0016] As a further improvement to the above technology, the first electromagnetic heating is a solid preheating zone with an internal temperature range of room temperature to 580°C, and the first electromagnetic heating coil is a circumferentially arranged medium-frequency electromagnetic coil with a frequency of 1-3kHz.

[0017] The second electromagnetic heating zone is an overheated zone with an internal temperature range of 580°C to 690°C. The second electromagnetic heating coil is a circumferentially arranged high-frequency electromagnetic coil with a frequency of 5-10kHz.

[0018] As a further improvement to the above technology, the nitrogen protection system includes a nitrogen delivery system consisting of a nitrogen source, a solenoid valve, and a nitrogen one-way delivery path, and a nitrogen circulation system consisting of a nitrogen buffer chamber, a circulating fan, and a nitrogen circulation path connecting the nitrogen inlet and the exhaust outlet. The nitrogen source delivers nitrogen to the nitrogen buffer chamber via the solenoid valve and the nitrogen one-way delivery path. An oxygen content sensor is installed at the exhaust outlet. The oxygen content sensor is electrically connected to the controller and then to the solenoid valve. An oxygen content threshold is set in the controller, and the opening and closing degree of the solenoid valve is adjusted by the oxygen content monitored by the oxygen content sensor to control the flow rate of nitrogen in the nitrogen one-way delivery path.

[0019] As a further improvement to the above technology, the nitrogen flow rate at the nitrogen inlet is 1-30 m³ / h. 3 / h, and the pressure of the nitrogen inflow is maintained at 50Pa to 200Pa higher than atmospheric pressure.

[0020] This utility model also discloses a smelting method for the above-mentioned high-efficiency, low-oxidation aluminum smelting equipment, the specific steps of which are as follows:

[0021] (1) The aluminum block is put into the upper end of the melting tube. Using its own weight, the aluminum block is heated to near the melting point of 580°C in the lower temperature environment inside the first electromagnetic heating zone and then melted into aluminum molten liquid.

[0022] (2) The molten aluminum obtained in step (1) enters the second electromagnetic heating zone. The solenoid valve is opened, and the nitrogen gas source is delivered to the nitrogen buffer chamber and then enters the second electromagnetic heating zone through the nitrogen inlet of the melting tube. The molten aluminum is overheated under the positive pressure protection of the nitrogen protection system.

[0023] (3) Set the oxygen content threshold to 0.005wt in the controller and ensure that the oxygen content in the second electromagnetic heating zone is ≤0.005wt through the oxygen content sensor.

[0024] The specific process for controlling the oxygen content in step (3) above is as follows:

[0025] (31) The oxygen content sensor collects the oxygen concentration value inside the second electromagnetic heating zone and converts the oxygen concentration into an electrical signal.

[0026] (32) Transmit the electrical signal to the controller and compare it with the preset oxygen content threshold in the controller to calculate the difference that needs to be adjusted;

[0027] (33) The controller generates a corresponding control signal based on the above difference. The signal strength corresponds to the opening degree that the solenoid valve needs to achieve and realizes precise control of the opening degree, as well as controlling the oxygen content within the range of ≤0.005wt%.

[0028] Compared with the prior art, the beneficial effects of this utility model are:

[0029] (1) The high-efficiency and low-oxidation aluminum smelting equipment of this utility model places the smelting tube at an inclination and uses its own weight to pass through the first electromagnetic heating zone inside the smelting tube at a uniform speed. The tube is heated to near the melting point in a low-temperature environment and then melted into aluminum molten liquid. It then enters the second electromagnetic heating zone with high temperature and nitrogen protection. This ensures that the aluminum molten liquid is overheated in an atmosphere with low oxygen content and high nitrogen protection, avoiding aluminum oxidation and reducing the aluminum burn-off rate to below 1%. The aluminum smelting efficiency is high and the effect is good.

[0030] (2) The high-efficiency, low-oxidation aluminum smelting equipment described in this utility model ensures that the oxygen content in the second electromagnetic heating zone can be continuously and accurately controlled through the precise control of the oxygen content sensor, controller and nitrogen gas source electromagnetic valve, reducing the rapid oxidation of aluminum melt at high temperature, effectively ensuring that the aluminum burn-off rate is stable at a low level, and the finished product quality after aluminum smelting is stable. Attached Figure Description

[0031] The present invention will now be described in detail with reference to the accompanying drawings and specific embodiments:

[0032] Figure 1 This is a schematic diagram of the structure of the high-efficiency, low-oxidation aluminum smelting equipment described in this utility model;

[0033] Figure 2 This is a schematic diagram of the melting tube and electromagnetic heating system in this utility model. Detailed Implementation

[0034] like Figure 1 , Figure 2 As shown, the present invention provides a high-efficiency, low-oxidation aluminum smelting equipment, comprising:

[0035] Melting tube 1: The two open ends of the melting tube 1 are fixed and arranged at an angle. The two open ends can usually be fixed by channel steel or square tube.

[0036] Electromagnetic heating system: The melting tube 1 is divided into a first electromagnetic heating system and a second electromagnetic heating system from top to bottom. The first electromagnetic heating system includes a first electromagnetic heating coil 2 wound around the outer periphery of the upper half of the melting tube 1, which corresponds to the first electromagnetic heating zone 11 in the inner cavity of the upper half of the melting tube 1 for solid-state preheating of aluminum blocks; and a second electromagnetic heating coil 3 wound around the outer periphery of the lower half of the melting tube 1, which corresponds to the second electromagnetic heating zone 12 in the inner cavity of the lower half of the melting tube 1 for high-temperature melting of liquid aluminum;

[0037] Nitrogen protection system 4: Nitrogen is introduced into the second electromagnetic heating zone 12, including a nitrogen inlet 410 and an exhaust outlet 420. The nitrogen inlet 410 is located at the starting end side wall I of the second electromagnetic heating zone 12, and the exhaust outlet 420 is located at the bottom end side wall O of the melting tube 1.

[0038] In this utility model, the diameter Φ of the melting tube 1 is 300mm-500mm, its inclination angle A ranges from 30° to 60°, and its length is 2m-12m.

[0039] like Figure 1 , Figure 2As shown, the first electromagnetic heating zone 11 is a solid preheating zone with an internal temperature range of room temperature to 580°C. The first electromagnetic heating coil 2 is a circumferentially arranged medium-frequency electromagnetic coil with a frequency of 1-3kHz. The second electromagnetic heating zone 12 is an overheating zone with an internal temperature range of 580°C to 690°C. The second electromagnetic heating coil 3 is a circumferentially arranged high-frequency electromagnetic coil with a frequency of 5-10kHz.

[0040] like Figure 1 As shown, the nitrogen protection system 4 includes a nitrogen delivery system consisting of a nitrogen source 41, a solenoid valve 42, and a nitrogen one-way delivery air path 43, and a nitrogen circulation system consisting of a nitrogen buffer chamber 44, a circulating fan 45, and a nitrogen circulation air path 46 connecting the nitrogen inlet 410 and the exhaust outlet 420. The nitrogen source 41 delivers nitrogen to the nitrogen buffer chamber 44 via the solenoid valve 42 and the nitrogen one-way delivery air path 43. An oxygen content sensor 47 is installed at the exhaust outlet 420. The oxygen content sensor 47 is electrically connected to the controller 48 and then to the solenoid valve 42. An oxygen content threshold is set in the controller 48. The opening and closing degree of the solenoid valve 42 is adjusted by the oxygen content monitored by the oxygen content sensor 47 to control the flow rate of nitrogen in the nitrogen one-way delivery air path 43. The delivered nitrogen can also circulate inside the nitrogen circulation system to reduce nitrogen waste.

[0041] In this invention, to better achieve nitrogen protection, the nitrogen flow rate at the nitrogen inlet 41 is 1-30 m³ / h. 3 / h, and the pressure of the nitrogen inflow is maintained at 50Pa to 200Pa higher than atmospheric pressure.

[0042] This utility model also discloses a smelting method for the above-mentioned high-efficiency, low-oxidation aluminum smelting equipment, the specific steps of which are as follows:

[0043] (1) The aluminum block is put into the upper end of the melting tube 1. Using its own weight, the aluminum block is heated to near the melting point of 580°C in the lower temperature environment inside the first electromagnetic heating zone 11 and then melted into aluminum molten liquid.

[0044] (2) The aluminum melt obtained in step (1) above slides down by its own weight into the second electromagnetic heating zone 12. The solenoid valve 42 is opened, and the nitrogen gas source 41 is delivered to the nitrogen buffer chamber 44 and then enters the second electromagnetic heating zone 12 through the nitrogen inlet 410 of the melting pipe 1. The aluminum melt is overheated under the positive pressure protection of the nitrogen protection system 4.

[0045] (3) Set the oxygen content threshold of 0.005wt in the controller 48, and ensure that the oxygen content of the second electromagnetic heating zone 12 is ≤0.005wt through the oxygen content sensor 47.

[0046] The following is the specific process for controlling the oxygen content in step (3) of this invention:

[0047] (31) The oxygen content sensor 47 collects the oxygen concentration value inside the second electromagnetic heating zone 12 and converts the oxygen concentration into an electrical signal.

[0048] (32) Transmit the electrical signal to the controller 48 and compare it with the preset oxygen content threshold in the controller 48 to calculate the difference that needs to be adjusted.

[0049] (33) The controller 48 generates a corresponding control signal based on the above difference. The signal strength corresponds to the opening degree that the solenoid valve needs to achieve and realizes precise control of the opening degree, as well as controlling the oxygen content within the range of ≤0.005wt%.

[0050] This invention can effectively prevent aluminum oxidation, reduce the aluminum burn-off rate to below 1%, and significantly improve the cleanliness of molten aluminum and the economic efficiency of production.

[0051] This utility model is not limited to the above-described embodiments. Any modifications or variations to this utility model that do not depart from the spirit and scope of this utility model, and if such modifications and variations fall within the scope of the claims and equivalent technologies of this utility model, then this utility model also includes such modifications and variations.

Claims

1. A high-efficiency, low-oxidation aluminum smelting equipment, characterized in that: include, Melting tube: The two open ends of the melting tube are fixed and arranged at an angle; Electromagnetic heating system: The melting tube is divided into a first electromagnetic heating system and a second electromagnetic heating system from top to bottom. The first electromagnetic heating system includes a first electromagnetic heating coil wound around the outer periphery of the upper half of the melting tube, which corresponds to the first electromagnetic heating zone in which the aluminum block is preheated in solid state in the inner cavity of the upper half of the melting tube; and a second electromagnetic heating coil wound around the outer periphery of the lower half of the melting tube, which corresponds to the second electromagnetic heating zone in which the liquid aluminum is melted at high temperature in the inner cavity of the lower half of the melting tube. Nitrogen protection system: Nitrogen gas is supplied to the second electromagnetic heating zone for protection. It includes a nitrogen inlet and an exhaust outlet. The nitrogen inlet is located on the side wall at the beginning of the second electromagnetic heating zone, and the exhaust outlet is located on the bottom side wall of the melting tube.

2. The high-efficiency, low-oxidation aluminum smelting equipment according to claim 1, characterized in that: The diameter Φ of the smelting tube is 300mm-500mm, its inclination angle A ranges from 30° to 60°, and its length is 2m-12m.

3. The high-efficiency, low-oxidation aluminum smelting equipment according to claim 1, characterized in that: The first electromagnetic heating zone is a solid preheating zone, and its internal temperature range is from room temperature to 580°C. The first electromagnetic heating coil is a circumferentially arranged medium-frequency electromagnetic coil, and the frequency of the first electromagnetic heating coil is 1-3kHz. The second electromagnetic heating zone is an overheated zone with an internal temperature range of 580°C to 690°C. The second electromagnetic heating coil is a circumferentially arranged high-frequency electromagnetic coil with a frequency of 5-10kHz.

4. The high-efficiency, low-oxidation aluminum smelting equipment according to claim 1, characterized in that: The nitrogen protection system includes a nitrogen delivery system consisting of a nitrogen source, a solenoid valve, and a nitrogen one-way delivery path, and a nitrogen circulation system consisting of a nitrogen buffer chamber, a circulating fan, and a nitrogen circulation path connecting the nitrogen inlet and the exhaust outlet. The nitrogen source delivers nitrogen to the nitrogen buffer chamber via the solenoid valve and the nitrogen one-way delivery path. An oxygen content sensor is installed at the exhaust outlet. The oxygen content sensor is electrically connected to a controller and then to the solenoid valve. An oxygen content threshold is set in the controller. The opening and closing degree of the solenoid valve is adjusted by the oxygen content monitored by the oxygen content sensor to control the flow rate of nitrogen in the nitrogen one-way delivery path.

5. The high-efficiency, low-oxidation aluminum smelting equipment according to claim 1, characterized in that: The nitrogen flow rate at the nitrogen inlet is 1-30 m³ / h. 3 / h, and the pressure of the nitrogen inflow is maintained at 50Pa to 200Pa higher than atmospheric pressure.

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