Molten aluminum refining and purifying process

Abstract

The invention relates to the technical field of metal refining methods, and particularly discloses a molten aluminum refining and purifying process which comprises the following steps of raw material detection, burdening, melting, alloying, refining agent I adding, primary deslagging, refining agent II adding, secondary deslagging, liquid state detection, heat preservation in a heat preservation furnace, bagging, deslagging and molten aluminum production. According to the method, the refining agents with different masses, raw materials and particle sizes are added twice, various temperatures and time in the technological process are limited, parameters of fed gas are limited, the prepared molten aluminum is high in purity, and the technological process is simple and convenient.

Description

Technical Field

[0001] The present application relates to the technical field of metal refining methods, and more specifically, to a process for refining and purifying molten aluminum. Background Art

[0002] High-purity aluminum boasts superior conductivity, toughness, reflectivity, and corrosion resistance compared to primary aluminum. Electronic aluminum foil accounts for 78% of total aluminum foil consumption and is widely used in high-tech fields. Currently, Germany, the United States, Japan, France, and Russia possess the production capacity for high-purity aluminum. In the current context of increasingly competitive markets and overcapacity, high-purity aluminum, as a fundamental raw material for high-tech products, offers high added value and profit margins. The development of production processes for producing high-purity aluminum through the refining and purification of molten aluminum is of great significance to the development of China's light metals industry.

[0003] At present, the aluminum molten refining process mainly adopts electrochemical refining and segregation smelting. The latter has low energy consumption, low labor intensity and low pollution, and is popular among people. However, it is difficult to ensure that the purity of the produced aluminum molten is fully up to standard. How to provide an aluminum refining and purification process that can simply produce higher purity aluminum molten and improve the quality of aluminum alloy products is a problem that needs to be solved. Summary of the Invention

[0004] In order to solve the problem of low purity of molten aluminum, the present application provides a molten aluminum refining and purification process.

[0005] The present application provides a molten aluminum refining and purification process, which is characterized by comprising the following steps: raw material detection, batching, melting, alloying, adding refining agent I, primary slag removal, adding refining agent II, secondary slag removal, liquid state detection, holding furnace insulation, ladle filling, slag removal, and molten aluminum production.

[0006] By adopting the above scheme and adding refining agents twice, the obtained molten aluminum has high purity, and the solidified aluminum is silvery white, with a smooth surface, clear crystal lines, and no inclusions.

[0007] In a specific embodiment, refining agent I includes the following raw materials in parts by mass: 60-80 parts of sodium nitrate, 10-15 parts of cryolite, 10-15 parts of graphite powder, 10-15 parts of sodium chloride, 10-15 parts of potassium chloride, 5-10 parts of magnesium chloride, 5-10 parts of potassium fluoroaluminate, and 5-10 parts of sodium fluoride; the refining agent II includes the following raw materials in parts by mass: 60-80 parts of sodium nitrate, 30-35 parts of cryolite, 10-15 parts of graphite powder, 10-15 parts of sodium chloride, 10-15 parts of potassium chloride, and 5-10 parts of magnesium chloride.

[0008] By adopting the above technical solution, refining agent I and refining agent II have good refining properties, covering properties and slag removal properties, good fluidity in molten aluminum, and are easy to separate.

[0009] By adding a certain amount of sodium nitrate to refining agent I, it decomposes at high temperature to generate gases such as N2, CO2, and NO, thereby refining and purifying molten aluminum; adding a small amount of cryolite to disperse bubbles makes the refining effect more stable; adding a certain amount of graphite powder to react to generate nitrogen and carbon dioxide, hydrogen diffuses into the bubbles and increases the possibility of oxidation, further strengthening the degassing effect; by adding a certain amount of chloride, inert gas is generated to absorb hydrogen bubbles and highly wettable adsorbable small particles of impurities; potassium fluoroaluminate, sodium fluoride, and non-metallic compounds in the molten aluminum The oxides react with harmful gases such as hydrogen to enhance the purification effect, generate gases to break through the oxide film, and increase the surface tension of the refining agent. The speed of adsorption and impurity removal is faster, impurities are adsorbed on the surface of the refining agent and spheroidized, making it easier to refine and remove slag from molten aluminum with more impurities, and the impurity removal effect is good. By adding a larger proportion of cryolite to refining agent II than to refining agent I, the refining agent is better dispersed, the bubbles are more refined, the contact area between gas and molten aluminum is larger, and the impurity removal effect inside the molten aluminum that has undergone one impurity removal is better, with fewer residual pores.

[0010] In a specific embodiment, the preparation of refining agent I and refining agent II respectively comprises the following steps: weighing the raw materials by mass, drying, mixing, granulating, drying, and cooling to room temperature.

[0011] Preferably, a dry granulator is used for granulation.

[0012] By adopting the above technical solution, the crystal water inside the refining agent is fully dried, the mixing is relatively uniform, and the preparation process is simple.

[0013] In a specific embodiment, the particle size of the refining agent I is 2-5 mm, and the particle size of the refining agent II is 0.5-2 mm.

[0014] By adopting the above technical solution, the particle size of the refining agent is suitable for the components of the refining agent in this application and the needs of the aluminum liquid. The particle size of the refining agent I added for the first time is larger, and it is easier to form spherical impurities during the impurity adsorption process during the impurity removal process, and the slag removal is more complete. The particle size of the refining agent II added for the second time is smaller, and the contact area with the aluminum liquid is larger, the impurity removal process is more refined, and there are fewer residual impurities and bubbles. During the impurity removal process, the oxide film and air on the surface of the aluminum liquid are not easily stirred in, and secondary air inhalation is not easy, so the obtained aluminum liquid has high purity.

[0015] In a specific embodiment, the mass of refining agent I added to molten aluminum is 0.5-3 kg / t.

[0016] By adopting the above technical solution, the molten aluminum is refined effectively without leaving a large amount of refining agent that has not participated in the reaction.

[0017] In a specific embodiment, the mass ratio of refining agent I to refining agent II is 1:(1-1.3).

[0018] By adopting the above technical solution, the quality of the added refining agent is appropriate, the quality of the refining agent added for the second time is slightly more than that of the first refining agent, the finer refining agent added for the second time is fully dispersed in the aluminum liquid, floats and is adsorbed, and the slag is completely removed.

[0019] In a specific embodiment, the melting temperature is 650-750° C., and the melting time is 40-60 minutes.

[0020] By adopting the above technical solution, the melting temperature is appropriate, no more hydrogen sensitive to the melting temperature is introduced, the surface oxide film is not damaged, the melting time is suitable for the aluminum liquid and refining agent of this application, and no more oxide inclusions are generated.

[0021] In a specific embodiment, the refining temperature when adding refining agent I and refining agent II is 690-720° C., and the refining time is 10-12 minutes.

[0022] By adopting the above technical solution and limiting the refining temperature and time, the aluminum liquid and refining agent applicable to the present application have good impurity removal effects and good effects in removing oxide slag inclusions.

[0023] In a specific embodiment, refining agent I and refining agent II are respectively sprayed into the aluminum liquid surface by mixed gas, and the mixed gas includes chlorine, argon and nitrogen in a volume ratio of 1:4:4.

[0024] By adopting the above technical solution, the mixed gas forms fine bubbles, and the refining agent is sprayed into the lower part of the molten aluminum surface more smoothly and evenly. At the same time, the particles of the refining agent enhance the activity of the bubble surface. The bubbles entrain oxides on the surface and absorb hydrogen, which gathers on the surface of the molten aluminum after floating up, so as to better purify it. By limiting the mixed gas to chlorine, argon and nitrogen in a volume ratio of 1:4:4, hydrogen is further absorbed, and hydrogen atoms in the molten aluminum are taken out during the floating process, thereby reducing harm to the human body and making the obtained molten aluminum structure more uniform.

[0025] In a specific embodiment, the mixed gas flow rate is 20-22 L / min, the purity is 99.99%, and the pressure is 0.3-0.35 MPa.

[0026] By adopting the above technical solution, the gas flow rate is limited to suit the density of the molten aluminum and refining agent of this application, and the refining agent enters the molten aluminum liquid surface evenly and smoothly, preventing the oxide film on the surface of the molten aluminum and air from being stirred into the molten aluminum, making it difficult to absorb air again, reducing the eddy current of the molten aluminum, and allowing the impurities to be completely deslagging after being adsorbed.

[0027] In summary, this application has the following beneficial effects: 1. This application effectively removes hydrogen and oxidized slag from molten aluminum by adding refining agents twice, and by defining the composition, particle size, and mass ratio of the two refining agents. By ensuring that the second addition of refining agent II is slightly greater than the first addition of refining agent I, the refining effect is further enhanced, which is consistent with the refining agents and process of this application.

[0028] 2. The temperature, time and other process parameters of the refining process of this application are suitable for the refining agent components of this application, which can fully exert the refining effect without introducing too much hydrogen and destroying the surface oxide film.

[0029] 3. This application limits the refining agent to be introduced through a mixed gas, and further limits the mixed gas to chlorine, argon and nitrogen in a volume ratio of 1:4:4, and further limits the gas flow, purity and pressure. The refining agent is evenly dispersed and does not require secondary air absorption, so the purity of the obtained molten aluminum is relatively high. DETAILED DESCRIPTION

[0030] The present application is further described in detail below with reference to the examples. Unless otherwise specified, the experimental reagents in the preparation examples and examples are all conventional commercial brands or obtained through conventional preparation processes.

[0031] Preparation Example Preparation Example 1: Preparation of Refining Agent I The refining agent I of this preparation example includes the following raw materials: 600g sodium nitrate, 100g cryolite, 100g graphite powder, 150g sodium chloride, 150g potassium chloride, 100g magnesium chloride, 50g potassium fluoroaluminate, and 50g sodium fluoride.

[0032] The preparation process is as follows: The raw materials were weighed by mass, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 2 mm.

[0033] Preparation Example 2: Preparation of Refining Agent I The refining agent I of this preparation example includes the following raw materials: 800g of sodium nitrate, 150g of cryolite, 100g of graphite powder, 150g of sodium chloride, 150g of potassium chloride, 100g of magnesium chloride, 100g of potassium fluoroaluminate, and 100g of sodium fluoride.

[0034] The preparation process is as follows: The raw materials were weighed by mass, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 2 mm.

[0035] Preparation Example 3: Preparation of Refining Agent I The refining agent I of this preparation example includes the following raw materials: 700g sodium nitrate, 125g cryolite, 125g graphite powder, 150g sodium chloride, 100g potassium chloride, 100g magnesium chloride, 100g potassium fluoroaluminate, 50g sodium fluoride.

[0036] The preparation process is as follows: The raw materials were weighed by mass, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 2 mm.

[0037] Preparation Example 4: Preparation of Refining Agent I The refining agent I of this preparation example includes the following raw materials: 600g sodium nitrate, 100g cryolite, 100g graphite powder, 150g sodium chloride, 150g potassium chloride, 100g magnesium chloride, 50g potassium fluoroaluminate, and 50g sodium fluoride.

[0038] The preparation process is as follows: The raw materials were weighed by weight, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 5 mm.

[0039] Preparation Example 5: Preparation of Refining Agent I The refining agent I of this preparation example includes the following raw materials: 600g sodium nitrate, 100g cryolite, 100g graphite powder, 150g sodium chloride, 150g potassium chloride, 100g magnesium chloride, 50g potassium fluoroaluminate, and 50g sodium fluoride.

[0040] The preparation process is as follows: The raw materials were weighed by weight, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 7 mm.

[0041] Preparation Example 6: Preparation of Refining Agent II The refining agent II of this preparation example includes the following raw materials: 600g sodium nitrate, 300g cryolite, 150g graphite powder, 150g sodium chloride, 150g potassium chloride, 50g magnesium chloride.

[0042] The preparation process is as follows: The raw materials were weighed by weight, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 0.5 mm.

[0043] Preparation Example 7: Preparation of Refining Agent II The refining agent II of this preparation example includes the following raw materials: 800g sodium nitrate, 350g cryolite, 100g graphite powder, 100g sodium chloride, 100g potassium chloride, 50g magnesium chloride.

[0044] The preparation process is as follows: The raw materials were weighed by weight, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 0.5 mm.

[0045] Preparation Example 8: Preparation of Refining Agent II The refining agent II of this preparation example includes the following raw materials: 600g sodium nitrate, 300g cryolite, 150g graphite powder, 150g sodium chloride, 150g potassium chloride, 50g magnesium chloride.

[0046] The preparation process is as follows: The raw materials were weighed by mass, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 2 mm.

[0047] Preparation Example 9: Preparation of Refining Agent II The refining agent II of this preparation example includes the following raw materials: 600g sodium nitrate, 100g cryolite, 100g graphite powder, 150g sodium chloride, 150g potassium chloride, 100g magnesium chloride, 50g potassium fluoroaluminate, 50g sodium fluoride; The preparation process is as follows: The raw materials were weighed by weight, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 0.5 mm.

[0048] Preparation Example 10: Preparation of Refining Agent III The refining agent I of this preparation example includes the following raw materials: 600g sodium nitrate, 200g graphite powder, 100g cryolite.

[0049] The preparation process is as follows: The raw materials were weighed by mass, dried at 200°C for 5 hours, mixed, granulated in a granulator, dried, cooled to room temperature, and sieved to obtain particles with an average particle size of 2 mm. Example

[0050] Example 1 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1kg / t of molten aluminum, a volume flow rate of 20L / min, a purity of 99.99%, a pressure of 0.3MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0051] Example 2 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 2. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0052] Example 3 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 3. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0053] Example 4 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 4. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0054] Example 5 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 5. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0055] Example 6 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1kg / t of molten aluminum, a volume flow rate of 20L / min, a purity of 99.99%, a pressure of 0.3MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 7 was sprayed into the molten aluminum at a mass ratio of 1kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0056] Example 7 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1kg / t of molten aluminum, a volume flow rate of 20L / min, a purity of 99.99%, a pressure of 0.3MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 8 was sprayed into the molten aluminum at a mass ratio of 1kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0057] Example 8 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 9 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0058] Example 9 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 0.8 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0059] Example 10 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, refining agent I prepared in Preparation Example 1 was sprayed into the mixture through nitrogen. The mass of the refining agent sprayed was 1 kg / t of molten aluminum, the volume flow rate was 20 L / min, the purity was 99.99%, the pressure was 0.3 MPa, and the slag was removed after refining at 720°C for 10 minutes. Then, refining agent II prepared in Preparation Example 6 was sprayed into the mixture at a mass ratio of 1 kg / t of molten aluminum. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, ladle filling was performed, slag removal was performed, and molten aluminum was produced.

[0060] Example 11 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 4 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1 kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0061] Example 12 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1kg / t of molten aluminum, a volume flow rate of 25L / min, a purity of 99.99%, a pressure of 0.5MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent II prepared in Preparation Example 6 was sprayed into the molten aluminum at a mass ratio of 1kg / t. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0062] Comparative Example Comparative Example 1 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Then, the refining agent I prepared in Preparation Example 1 was sprayed at a mass ratio of 1 kg / t of molten aluminum. The slag was removed twice, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and molten aluminum was produced.

[0063] Comparative Example 2 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, a mixed gas of chlorine, argon and nitrogen with a volume ratio of 1:4:4 was sprayed into the refining agent I prepared in Preparation Example 1. The refining agent was sprayed with a mass of 1 kg / t of molten aluminum, a volume flow rate of 20 L / min, a purity of 99.99%, a pressure of 0.3 MPa, and slag was removed after refining at 720°C for 10 minutes. Liquid testing was performed, the alloy was kept at 700°C in a holding furnace for two hours, filled into a ladle, and the slag was removed. The molten aluminum was then produced.

[0064] Comparative Example 3 Raw material testing: 4000 series aluminum alloy was added to a melting furnace preheated at 650°C, melted at 700°C for 50 minutes, titanium agent (LY-Ti75 purchased from Lvyuan Intelligent Equipment Manufacturing Co., Ltd.) was added, and after melting evenly, refining agent I prepared in Preparation Example 10 was sprayed into the mixture with a volume ratio of 1:4:4 of chlorine, argon and nitrogen. The mass of the refining agent sprayed was 1 kg / t of molten aluminum, the volume flow rate was 20 L / min, the purity was 99.99%, the pressure was 0.3 MPa, and the slag was removed after refining at 720°C for 10 minutes. Then, the refining agent I prepared in Preparation Example 10 was sprayed into the mixture at a mass ratio of 1 kg / t of molten aluminum. The slag was removed for the second time, liquid state testing was performed, the mixture was kept at 700°C in a holding furnace for two hours, filled into a ladle, slag removed, and the molten aluminum was produced.

[0065] Performance Test Test 1: Density ratio equivalent (DI) was tested on the molten aluminum from each Example and Comparative Example. The test process used the ratio of the density change between samples solidified under atmospheric pressure and under reduced pressure to determine the slag and gas content of the aluminum ingot. The test results are shown in Table 1.

[0066] Test 2: The molten aluminum of each embodiment and comparative example was tested for slag content. The test process was similar to the K-Mold test: 20 slag points on the K-Mold fracture surface were taken to determine the slag content. The test results are shown in Table 1.

[0067] Table 1 In combination with Examples 1-3, 6, 8, 10, Comparative Examples 1, 2, 3 and Table 1, the present application is suitable for the refining process of the present application by adding refining agents of different components in two batches, and limits the process parameters in the refining process. The refining agent is evenly dispersed, the bubbles are fully adsorbed, the refining effect is good, and the obtained molten aluminum has fewer bubbles and less slag.

[0068] In combination with Examples 1, 4, 5, and 7 and Table 1, the present application limits the particle size of the refining agent, further improves the bubble refinement, and the obtained molten aluminum has a higher purity.

[0069] In combination with Examples 1 and 9 and Table 1, the present application further optimizes the refining process by limiting the added mass ratio of refining agent I and refining agent II. During the second addition of the refining agent, impurities are fully removed through the refined refining components, and the refining effect is good.

[0070] In combination with Examples 1 and 10 and Table 1, the present application limits the components of the mixed gas to further improve the refining effect.

[0071] In combination with Examples 1 and 11 and Table 1, the present application defines the mass ratio of the added refining agent, and the molten aluminum is fully refined.

[0072] In combination with Examples 1 and 12 and Table 1, the present application defines parameters such as the flow rate and pressure of the mixed gas. After the gas is introduced, the refining agent can be fully dispersed, and the oxide film on the surface of the molten aluminum and the air are not stirred into the molten aluminum. There are fewer eddies and the slag removal effect is good.

[0073] The specific embodiment adopted in this application is merely an explanation of this application, and it is not a limitation of this application. After reading this specification, those skilled in the art may make non-creative modifications to this embodiment as needed, but as long as they are within the scope of the claims of this application, they are protected by the patent law.

Claims

1. A molten aluminum refining and purification process, characterized by: The following steps are involved: Raw material testing, batching, melting, alloying, adding refining agent I, primary slag removal, adding refining agent II, secondary slag removal, liquid state testing, holding furnace insulation, ladle filling, slag removal, and molten aluminum production.

2. The aluminum molten refining and purification process according to claim 1, characterized in that: The refining agent I comprises the following raw materials in parts by mass: 60-80 parts of sodium nitrate, 10-15 parts of cryolite, 10-15 parts of graphite powder, 10-15 parts of sodium chloride, 10-15 parts of potassium chloride, 5-10 parts of magnesium chloride, 5-10 parts of potassium fluoroaluminate, and 5-10 parts of sodium fluoride; the refining agent II comprises the following raw materials in parts by mass: 60-80 parts of sodium nitrate, 30-35 parts of cryolite, 10-15 parts of graphite powder, 10-15 parts of sodium chloride, 10-15 parts of potassium chloride, and 5-10 parts of magnesium chloride.

3. The aluminum molten refining and purification process according to claim 1, characterized in that: The preparation of the refining agent I and the refining agent II respectively comprises the following steps: weighing the raw materials by mass, drying, mixing, granulating, drying, and cooling to room temperature.

4. The aluminum molten refining and purification process according to claim 1, characterized in that: The particle size of the refining agent I is 2-5 mm, and the particle size of the refining agent II is 0.5-2 mm.

5. The aluminum molten refining and purification process according to claim 1, characterized in that: The mass of the refining agent I added to the molten aluminum is 0.5-3 kg / t.

6. The aluminum molten refining and purification process according to claim 1, characterized in that: The mass ratio of the refining agent I to the refining agent II is 1:(1-1.3).

7. The aluminum molten refining and purification process according to claim 1, characterized in that: The melting temperature is 650-750° C., and the melting time is 40-60 minutes.

8. The aluminum molten refining and purification process according to claim 1, characterized in that: The refining temperature when adding the refining agent I and the refining agent II is 720-730° C., and the refining time is 10-12 minutes.

9. The aluminum molten refining and purification process according to claim 1, characterized in that: The refining agent I and refining agent II are respectively sprayed into the aluminum liquid surface by mixed gas, and the mixed gas includes chlorine, argon and nitrogen with a volume ratio of 1:4:

4.

10. The aluminum molten refining and purification process according to claim 9, characterized in that: The mixed gas has a flow rate of 20-22 L / min, a purity of 99.99%, and a pressure of 0.3-0.35 MPa.

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