A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid

Abstract

A method for preparing 8079 double-zero aluminum foil billets using electrolytic aluminum liquid includes screening qualified electrolytic aluminum liquid, pre-treating the electrolytic aluminum liquid, batching, adjusting the aluminum liquid composition, alloy smelting, online processing, casting and cold rolling. The method can reduce the non-metallic inclusions, hydrogen and alkali metal contents entering the 8079 alloy double-zero foil billet production system, improve the purity of the melt, reduce the pressure of furnace refining and online processing, lay the foundation for the subsequent production of high-quality billets, effectively avoid chlorine pollution of equipment and the environment, and effectively reduce the content of harmful phase Al3Fe in the strip billet, thereby controlling the pinhole rate of the double-zero foil finished product.

Description

Technical Field

[0001] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid

[0002] The present invention belongs to the technical field of aluminum alloy strip preparation, and in particular relates to a method for preparing 8079 double-zero aluminum foil blank by utilizing electrolytic aluminum liquid. Background Art

[0003] Double-zero aluminum foil is widely used in the packaging industry. Its advantages, such as high barrier properties, lightweight, UV resistance, and long shelf life at room temperature, have led to a continuous increase in its application in the packaging field. Aluminum foil has become a key packaging material in food, beverages, dairy products, pharmaceuticals, household goods, and cigarette packaging. Due to the extremely thin thickness of the finished product, any inclusions or phases larger than 0.005mm within the material may increase the pinhole rate on the surface. Therefore, extremely stringent requirements are imposed on the base material's purity, metallurgical quality, chemical composition, surface and plate quality, as well as the material's internal structure and grain structure.

[0004] With advancements in aluminum foil processing technology and a growing emphasis on more economical and environmentally friendly processing methods, the production of double-zero aluminum foil billets has shifted from hot rolling to casting and rolling. Casting and rolling using electrolytic aluminum liquid is the shortest process, offering significant environmental and economic benefits, and has been widely adopted within the industry in recent years. Compared to using remelted aluminum ingots, electrolytic aluminum liquid has disadvantages such as inclusions, high hydrogen and alkali metal content, and overburning of the melt. This often results in substandard pinholes in double-zero aluminum foil due to improper casting and rolling process design, reducing product yield, causing significant economic losses to the company, and wasting social energy. Summary of the Invention

[0005] The purpose of the present invention is to provide a method for preparing 8079 double-zero aluminum foil billet using electrolytic aluminum liquid, so as to improve the metallurgical quality of the billet and increase the yield of double-zero aluminum foil products.

[0006] In order to achieve the above object, the technical solution adopted by the present invention is:

[0007] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid comprises the following steps:

[0008] S1. Screening of qualified electrolytic aluminum liquid:

[0009] Screening the electrolytic aluminum liquid that meets the requirements from the source of aluminum electrolysis as raw materials: the mass percentage of Fe in the electrolytic aluminum liquid is ≤ 0.13%, the mass percentage of Si is ≤ 0.05%, and the content of Na is ≤ 60ppm;

[0010] S2. Pretreatment of electrolytic aluminum liquid:

[0011] The electrolytic aluminum liquid obtained by S1 screening is placed in a vacuum ladle, and the powder spraying refining method is adopted. The refining agent is sprayed into the electrolytic aluminum liquid using argon gas. After standing, the pretreatment of the electrolytic aluminum liquid is completed. The refining agent is loaded into the aluminum liquid using argon gas to preliminarily remove hydrogen, non-metallic inclusions and alkali metals in the electrolytic aluminum liquid.

[0012] S3. Ingredients:

[0013] First, remove the upper layer of aluminum liquid in the vacuum ladle in S2, which accounts for 1 / 5 of the total electrolytic aluminum liquid, for separate use. Then remove the upper 2 / 3 of the remaining electrolytic aluminum liquid in the vacuum ladle. If one ladle is insufficient, repeat the aluminum liquid removal method in S2-S3 until the required amount is reached, thus obtaining spare aluminum liquid for double-zero foil billets. By using the pretreated electrolytic aluminum liquid in layers, aluminum liquid with higher purity is selected as the production raw material, and the inclusion content entering the 8079 alloy double-zero foil billet production system is controlled, creating conditions for producing high-quality and stable double-zero foil billets.

[0014] Charge the smelting furnace with solid materials first, then add the spare aluminum liquid. The weight of the solid materials should be controlled at 30-50% of the total weight of the materials.

[0015] S4. Adjust the composition of the molten aluminum:

[0016] The aluminum liquid in the smelting furnace is adjusted to have the following composition by mass percentage: Fe 0.70-0.90%, Si 0.10-0.20%, Ti 0.015-0.035%, Cu 0.015-0.030%, Re 0.05-0.08%, Mn ≤ 0.03%, other impurities ≤ 0.15%, and the balance is Al;

[0017] S5. Alloy melting:

[0018] (1) Refining in smelting furnace:

[0019] After the charge in the smelting furnace is completely melted, the temperature of the molten aluminum is raised to 725°C, and the molten aluminum is electromagnetically stirred for 10-15 minutes. When the melt temperature reaches 730°C, refining begins. Sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 1.5-2.0kg / t·Al. Argon is used to evenly load the sodium-free remelting granular refining agent into the molten aluminum. The refining time is 22-26 minutes. After standing for 20-35 minutes, slag is skimmed. The converter temperature of the smelting furnace melt is 740-755°C. The converter is started after the smelting furnace temperature and composition meet the control requirements.

[0020] (2) Refining in a static furnace:

[0021] The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar + sodium-free environmentally friendly refining agent with a refining agent dosage of 0.8-1.2kg / t·Al. Before each refining, 0.4-0.6% of the total mass of the melt in the furnace is added with aluminum ingots or cast-rolled aluminum plates of the same alloy. High-purity argon is used for refining.

[0022] S6. Online processing:

[0023] The melt obtained from S4 is processed online. The Al-Ti5-B1 ​​grain refiner is preheated and added at the degassing box inlet. The addition amount is 0.12-0.18% of the aluminum liquid passing through. The temperature of the preheated Al-Ti5-B1 ​​wire rod is not less than 400°C, and the temperature of the melt at the addition point is not less than 720°C. The online Ti increment is controlled at 0.005-0.008%. After flowing out of the degassing box, the aluminum liquid enters the filtration system. The filtration system adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series. The first stage of the double filtration system adopts 40PPI+60PPI ceramic filter plate, and the second stage adopts 16PPI tubular filter. The outlet temperature of the tubular filter is 710-715°C. The temperature drop of the aluminum liquid at the furnace eye, degassing box outlet, tubular filter outlet and front box outlet is not more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is not higher than 0.110ml / 100g·Al.

[0024] S7, Casting and Rolling:

[0025] The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spraying roller surface lubrication process is adopted. The casting and rolling area is 58-65mm long, the front box temperature is controlled at 695-705℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 750-850mm / min, the cooling water temperature is 32-35℃, and the cooling water flow rate is 100-130m 3 / h, producing cast-rolled strip with a thickness of 7.0-7.5mm and a center crown of 0.02-0.03mm. The temperature of the cast-rolled strip before coiling must not exceed 150°C, and cold rolling production begins after the coil temperature drops below 40°C. By balancing the various casting and rolling process parameters, uniform cooling during the crystallization process is achieved, improving the uniformity of the cast-rolled strip grain structure and preventing the formation of oversized secondary phases at grain boundaries or dendrite boundaries.

[0026] S8, cold rolling:

[0027] The cast strip obtained in S7 is cold rolled to 4.0 mm in one pass at a rolling speed of 200-400 m / min, and then homogenized annealing is performed. After the coil temperature reaches 560°C, a bipolar homogenization annealing process of 560°C / 10 h + 530°C / 6 h is adopted. After the annealing is completed, the coil is cooled with the furnace to a temperature below 300°C and then air-cooled. After the coil temperature is below 40°C, the strip is thinned from 4.0 mm to 0.6 mm in three passes, with the processing rate of each pass controlled at 40-60%. After trimming, intermediate annealing is performed at 320°C / 6 h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6 mm to a finished thickness of 0.22-0.26 mm. The tensile strength is 135-145 MPa, and the elongation is 3-5%. The processing of 8079 alloy double zero foil blank is completed. The use of gradient homogenization annealing + furnace cooling process can effectively control the size and spheroidization rate of the precipitated phase, improve the distribution uniformity in the thickness direction, and reduce the precipitation of Al3Fe phase.

[0028] In order to further realize the present invention, as described in S1, the electrolytic aluminum liquid that meets the requirements is screened from the aluminum electrolysis source as raw material, the working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.85-3.95V, the peak value of the working voltage fluctuation in the past three months is ≯0.6V, and the cell temperature is 930-940℃.

[0029] To further implement the present invention, the refining agent in S2 is composed of a uniform mixture of a sodium-free two-in-one powder refining agent and a sodium-free granular refining agent, the weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent being 1:1, the total refining agent dosage is 0.5-1.5 kg / t·Al, the refining time is 3-5 minutes, and the refining is allowed to stand for 5-10 minutes. The electrolytic aluminum liquid is preliminarily treated by an in-laundering pretreatment method to reduce the content of non-metallic inclusions, hydrogen, and alkali metals, thereby improving the purity of the electrolytic aluminum liquid.

[0030] In order to further realize the present invention, the solid material in S3 is Al99.80 grade remelted aluminum ingot and 8079 alloy cast plate waste.

[0031] In order to further realize the present invention, the smelting cycle of the smelting furnace in (1) of S5 is not more than 9 hours.

[0032] To further implement the present invention, in step (2) of S5, during the process of transferring the melt from the converter to the static furnace, AlTi10 alloy is evenly added to the molten aluminum twice from the chute. The amount of AlTi10 alloy added is 0.8‰ of the weight of the molten aluminum. During continuous production, the converter liquid level in the static furnace is not less than 300mm. This step can avoid the concentrated outflow of overburned melt caused by too low a liquid level, which deteriorates the grain structure of the billet, and the large-scale agitation of precipitated inclusions at the bottom of the furnace.

[0033] In order to further realize the present invention, the degassing box in S6 adopts a silicon nitride rotor for online degassing, the online refining gas is argon, the working gas pressure is 0.20-0.55MPa, the flow rate is 4-15L / Min, and the covering gas flow rate is 10-20L / Min.

[0034] In order to further realize the present invention, the wall thickness of the roller sleeve in S7 is 35-50 mm.

[0035] In order to further realize the present invention, the light transmittance of the rolling oil in the rolling process described in S8 is not less than 98%, and the surface roughness of the finished pass billet is Ra0.3-0.4μm.

[0036] The beneficial effects of the present invention compared to the prior art are:

[0037] The present invention selects relatively pure electrolytic aluminum liquid from the state of the electrolytic cell, pre-treats the electrolytic aluminum liquid through in-ladle refining, and selects electrolytic aluminum liquid with good melt quality as the raw material for the production of double-zero foil billets, thereby significantly reducing the non-metallic inclusions, hydrogen and alkali metal contents entering the 8079 alloy double-zero foil billet production system, laying the foundation for the subsequent production of high-quality billets.

[0038] The present invention, through the precise design of the furnace pre-treatment process, selectively uses the pre-treated electrolytic aluminum liquid in the vacuum ladle, selects the aluminum liquid with higher purity as the production raw material, controls the inclusion content entering the production system, improves the purity of the melt, significantly reduces the pressure of refining and online processing in the furnace, and improves the purity of the system melt.

[0039] The present invention improves the production process of 8079 alloy double-zero foil billets, adopts systematic furnace pretreatment methods, and combines ceramic filter plates and tubular filtration online treatment processes to remove slag inclusions larger than 5 μm in the melt through bipolar filtration. At the same time, hydrogen associated with slag gas is removed by filtration, so that the hydrogen content of the melt reaches the hydrogen removal efficiency that can only be achieved by using chlorine or chlorine-containing media, effectively avoiding chlorine pollution of equipment and the environment, and also providing ideas for the production of other products with high metallurgical quality requirements.

[0040] The present invention studies the influence of homogenization annealing on the microstructure of 8079 double zero foil blank, adopts a bipolar homogenization annealing process and a method of controlling the cooling rate of the coil after homogenization annealing, effectively reduces the content of harmful phase Al3Fe in the strip, and thus controls the pinhole rate of the double zero foil finished product. DETAILED DESCRIPTION

[0041] The present invention will be further described below with reference to specific embodiments.

[0042] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid comprises the following steps:

[0043] S1. Screening of qualified electrolytic aluminum liquid:

[0044] Screening the electrolytic aluminum liquid that meets the requirements from the source of aluminum electrolysis as raw materials: the mass percentage of Fe in the electrolytic aluminum liquid is ≤ 0.13%, the mass percentage of Si is ≤ 0.05%, and the content of Na is ≤ 60ppm;

[0045] S2. Pretreatment of electrolytic aluminum liquid:

[0046] The electrolytic aluminum liquid obtained by S1 screening is placed in a vacuum ladle, and the refining agent is sprayed into the electrolytic aluminum liquid using argon gas by adopting the method of powder spraying in the ladle. The electrolytic aluminum liquid is then allowed to stand for a period of time to complete the pretreatment of the electrolytic aluminum liquid.

[0047] S3. Ingredients:

[0048] First, take out the upper layer of aluminum liquid in the vacuum ladle in S2, which accounts for 1 / 5 of the total amount of electrolytic aluminum liquid, and then take out the upper 2 / 3 of the remaining electrolytic aluminum liquid in the vacuum ladle. If one bag is not enough, repeat the aluminum liquid taking method in S2-S3 until the required amount is reached, and obtain the spare aluminum liquid for double-zero foil billet;

[0049] Charge the smelting furnace with solid materials first, then add the spare aluminum liquid. The weight of the solid materials should be controlled at 30-50% of the total weight of the materials.

[0050] S4. Adjust the composition of the aluminum liquid:

[0051] The aluminum liquid in the smelting furnace is adjusted to have the following composition by mass percentage: Fe 0.70-0.90%, Si 0.10-0.20%, Ti 0.015-0.035%, Cu 0.015-0.030%, Re 0.05-0.08%, Mn ≤ 0.03%, other impurities ≤ 0.15%, and the balance is Al;

[0052] S5. Alloy melting:

[0053] (1) Refining in the smelting furnace:

[0054] After the charge in the smelting furnace is completely melted, the temperature of the molten aluminum is raised to 725°C, and the molten aluminum is electromagnetically stirred for 10-15 minutes. When the melt temperature reaches 730°C, refining begins. Sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 1.5-2.0kg / t·Al. Argon is used to evenly load the sodium-free remelting granular refining agent into the molten aluminum. The refining time is 22-26 minutes. After standing for 20-35 minutes, slag is skimmed. The converter temperature of the smelting furnace melt is 740-755°C. The converter is started after the smelting furnace temperature and composition meet the control requirements.

[0055] (2) Refining in a static furnace:

[0056] The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar + sodium-free environmentally friendly refining agent with a refining agent dosage of 0.8-1.2kg / t·Al. Before each refining, 0.4-0.6% of the total mass of the melt in the furnace is added with aluminum ingots or cast-rolled aluminum plates of the same alloy. High-purity argon is used for refining.

[0057] S6. Online processing:

[0058] The melt obtained from S4 is processed online. The Al-Ti5-B1 ​​grain refiner is preheated and added at the inlet of the degassing box. The addition amount is 0.12-0.18% of the aluminum liquid passing through. The temperature of the preheated Al-Ti5-B1 ​​wire rod is not less than 400℃, and the temperature of the melt at the addition point is not less than 720℃. The online Ti increment is controlled at 0.005-0.008%. After flowing out of the degassing box, the aluminum liquid enters the filtration system. The filtration system adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series.

[0059] S7, Casting and Rolling:

[0060] The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spraying roller surface lubrication process is adopted. The casting and rolling area is 58-65mm long, the front box temperature is controlled at 695-705℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 750-850mm / min, the cooling water temperature is 32-35℃, and the cooling water flow rate is 100-130m 3 / h, to obtain cast and rolled strip with a thickness of 7.0-7.5mm and a center crown of 0.02-0.03mm. The temperature of the cast and rolled strip before coiling shall not be higher than 150℃, and cold rolling production shall begin after the coil temperature is lower than 40℃.

[0061] S8, cold rolling:

[0062] The cast strip obtained in S7 is cold rolled to 4.0 mm in one pass at a rolling speed of 200-400 m / min, and then homogenized annealing is performed. After the coil temperature reaches 560°C, a bipolar homogenization annealing process of 560°C / 10 h + 530°C / 6 h is adopted. After the annealing is completed, the coil is cooled with the furnace to a temperature below 300°C and then air-cooled. After the coil temperature is below 40°C, the strip is thinned from 4.0 mm to 0.6 mm in three passes, with the processing rate of each pass controlled at 40-60%. After trimming, intermediate annealing is performed at 320°C / 6 h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6 mm to a finished thickness of 0.22-0.26 mm. The tensile strength is 135-145 MPa, and the elongation is 3-5%. The processing of 8079 alloy double zero foil blank is completed.

[0063] In S1, the electrolytic aluminum liquid that meets the requirements is selected from the source of aluminum electrolysis as raw material. The working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.85-3.95V, the peak value of the working voltage fluctuation in the past three months is ≯0.6V, and the cell temperature is 930-940℃.

[0064] The refining agent in S2 is preferably composed of a uniform mixture of a sodium-free two-in-one powder refining agent and a sodium-free granular refining agent, the weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent is 1:1, the total amount of the refining agent is 0.5-1.5 kg / t·Al, the refining time is 3-5 minutes, and the refining is allowed to stand for 5-10 minutes.

[0065] The solid material in S3 is preferably Al99.80 grade remelted aluminum ingot and 8079 alloy cast and rolled plate scrap.

[0066] The smelting cycle of the smelting furnace in (1) of S5 is preferably not more than 9 hours.

[0067] In (2) of S5, it is preferred that the AlTi10 alloy is evenly flushed into the aluminum liquid from the chute twice during the process of transferring the melt from the converter to the static furnace. The amount of AlTi10 alloy added is 0.8‰ of the weight of the aluminum liquid. During the continuous production process, the converter liquid level in the static furnace is not less than 300mm.

[0068] The degassing box in S6 preferably uses a silicon nitride rotor for online degassing, the online refining gas is argon, the working gas pressure is 0.20-0.55 MPa, the flow rate is 4-15 L / Min, and the covering gas flow rate is 10-20 L / Min.

[0069] In S6, a double filtration system in series is preferred. The first stage of filtration uses a 40PPI+60PPI ceramic filter plate, and the second stage of filtration uses a 16PPI tubular filter. The outlet temperature of the tubular filter is 710-715°C. The temperature drop of the aluminum liquid at the furnace eye, degassing box outlet, tubular filter outlet and front box is no more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is no more than 0.110ml / 100g·Al.

[0070] The wall thickness of the roller sleeve in S7 is preferably 35-50 mm.

[0071] During the S8 rolling process, the light transmittance of the rolling oil is not less than 98%, and the surface roughness of the finished product billet is Ra0.3-0.4μm.

[0072] Example 1:

[0073] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid comprises the following steps:

[0074] S1. Screening of qualified electrolytic aluminum liquid:

[0075] By screening the electrolytic cell state, we selected electrolytic aluminum liquid with relatively pure melt as the raw material for double-zero foil billets. The optimal working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.854V, the peak value of the working voltage fluctuation in the past three months is 0.6V, and the cell temperature is 940℃. Electrolytic aluminum liquid that meets the requirements is selected from the source of aluminum electrolysis as the raw material: the mass percentage of Fe in the electrolytic aluminum liquid is 0.010%, the mass percentage of Si is 0.04%, and the content of Na is 40ppm.

[0076] S2. Pretreatment of electrolytic aluminum liquid:

[0077] The electrolytic aluminum liquid obtained by S1 screening is loaded into a vacuum ladle and refined by powder spraying in the ladle. The weight of the aluminum liquid in the 1# ladle is 10.5t. Argon is used to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent is 1:1. The total amount of refining agent is 5.3kg. The refining time is 3min. After refining, the electrolytic aluminum liquid is allowed to stand for 5min to complete the pretreatment of the electrolytic aluminum liquid. To avoid one bag being insufficient, prepare another bag #2 and repeat the above method of taking out the molten aluminum until the required amount is reached. The weight of the molten aluminum in bag #2 is 9.5t. Use argon gas to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of sodium-free two-in-one powder refining agent and sodium-free granular refining agent is 1:1. The total amount of refining agent is 4.6kg. The refining time is 5min. After refining, let it stand for 10min to complete the pretreatment of the electrolytic aluminum liquid.

[0078] S3. Ingredients:

[0079] During the charging process of the smelting furnace, 15t was loaded according to the plan.

[0080] Add 1 / 5 of the weight of the aluminum liquid in the 1# ladle into the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.40t);

[0081] Add 1 / 5 of the weight of the aluminum liquid in the 2# ladle into the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.10t);

[0082] The planned total furnace load was 15.0t. The melting furnace was charged with solid materials, 2.8t of Al99.85 remelted aluminum ingots and 2.1t of 8079 alloy cast and rolled sheet scrap, first. Spare molten aluminum was then added, with 5.4t of molten aluminum from the 1# ladle added to the target melting furnace. Because one bag of qualified spare molten aluminum was insufficient, 4.6t of molten aluminum from the 2# ladle was added to the target melting furnace. The actual charge was 14.6t, with solid materials accounting for 32.9% of the total.

[0083] S4. Adjust the composition of the aluminum liquid:

[0084] During the process of adjusting the composition of the molten aluminum in the smelting furnace, aluminum-iron master alloy, aluminum-titanium master alloy, aluminum-copper master alloy, Al-Re master alloy and aluminum-silicon master alloy are used to adjust the molten aluminum in the smelting furnace to the following composition by mass percentage: Fe: 0.70%, Si: 0.20%, Ti: 0.015%, Cu: 0.015%, Re: 0.05%, Mn: 0.03%, impurity elements Ca: 0.005%, V: 0.007, and the balance is Al. Except for the Ti content, the contents of other elements are adjusted to the correct content in the smelting furnace.

[0085] S5. Alloy melting:

[0086] (1) Refining in the smelting furnace:

[0087] After the charge in the smelting furnace is completely melted, the temperature of the molten aluminum is raised to 725°C, and the molten aluminum is electromagnetically stirred for 10 minutes. When the melt temperature reaches 730°C, refining begins. The sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 22.5 kg. The sodium-free remelting granular refining agent is evenly loaded into the molten aluminum using argon gas. The refining time is 22 minutes. After standing for 20 minutes, the slag is skimmed. The converter temperature of the smelting furnace melt is 755°C. After the smelting furnace temperature and composition meet the control requirements, the converter is started.

[0088] (2) Refining in a static furnace:

[0089] The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar+sodium-free environmentally friendly refining agent and the refining agent dosage. For the remaining refining, 0.4-0.6% of the total mass of the melt in the furnace is added before each refining, and high-purity argon is used for refining.

[0090] During the process of transferring the melt from the converter to the static furnace, AlTi10 alloy is evenly poured into the molten aluminum from the chute twice. The amount of AlTi10 alloy added is 0.8‰ of the weight of the molten aluminum. During the continuous production process, the converter liquid level in the static furnace is maintained at 320mm.

[0091] S6. Online processing:

[0092] The melt obtained from S4 was processed online. The Al-Ti5-B1 ​​grain refiner was preheated and added at the degassing box inlet. The addition amount was 0.12% of the aluminum liquid throughput. The Al-Ti5-B1 ​​wire rod temperature after preheating was 420°C, and the temperature of the melt at the addition point was 725°C. The online Ti increment was controlled at 0.005%.

[0093] After flowing out of the degassing box, the aluminum liquid enters the filtration system, which adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series;

[0094] The degassing box uses a silicon nitride rotor for online degassing. The online refining gas is argon, with a working gas pressure of 0.20 MPa, a flow rate of 4 L / Min, and a cover gas flow rate of 10 L / Min.

[0095] The series double filtration system uses a 40PPI+60PPI ceramic filter plate (CFF) for the first stage and a 16PPI tubular filter (MCF) for the second stage. The outlet temperature of the tubular filter is 710°C. The temperature drop of the aluminum liquid at the furnace eye, degassing box outlet, tubular filter outlet and front box is no more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is 0.089ml / 100g·Al.

[0096] S7, Casting and Rolling:

[0097] The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spray roller surface lubrication process is adopted. The wall thickness of the roller sleeve is 50mm, the casting and rolling zone is 58mm long, the front box temperature is controlled at 695-705℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 750mm / min, the cooling water temperature is 35℃, and the cooling water flow rate is 100m 3 / h, obtaining a cast strip with a thickness of 7.0mm and a center crown of 0.02mm. The temperature of the cast strip before coiling is 150°C, and cold rolling production begins after the coil temperature reaches 38°C.

[0098] S8, cold rolling:

[0099] The cast strip obtained by S7 is cold rolled to 4.0mm in one pass, and the rolling speed is controlled at 220m / min, and then homogenized annealing is performed. After the coil temperature reaches 560℃, a bipolar homogenization annealing process of 560℃ / 10h+530℃ / 6h is adopted. After the annealing is completed, the coil is cooled to 280℃ with the furnace and then air-cooled. After the coil temperature is lower than 40℃, the strip is thinned from 4.0mm to 0.6mm by three passes, and the processing rate of each pass is controlled at 40-60%. After trimming, intermediate annealing is performed, and the annealing process is 320℃ / 6h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6mm to the finished product thickness of 0.22mm, the tensile strength is 135MPa, and the elongation (A 50 ) is 4%, and the 8079 alloy double zero foil billet is processed. The rolling oil transmittance during the intermediate rolling process is 98%, and the surface roughness of the finished billet is Ra0.3μm.

[0100] Example 2:

[0101] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid comprises the following steps:

[0102] S1. Screening of qualified electrolytic aluminum liquid:

[0103] By screening the state of the electrolytic cell, we selected electrolytic aluminum liquid with relatively pure melt as the raw material for double-zero foil billets. The optimal working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.95V, the peak value of the working voltage fluctuation in the past three months is 0.4V, and the cell temperature is 930℃. The electrolytic aluminum liquid that meets the requirements is selected from the source of aluminum electrolysis as the raw material: the mass percentage of Fe in the electrolytic aluminum liquid is 0.12%, the mass percentage of Si is 0.05%, and the content of Na is 52ppm.

[0104] S2. Pretreatment of electrolytic aluminum liquid:

[0105] The electrolytic aluminum liquid obtained by S1 screening is loaded into a vacuum ladle and refined by powder spraying in the ladle. The weight of the aluminum liquid in the 1# ladle is 10.5t. Argon is used to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent is 1:1. The total amount of refining agent is 15.8kg. The refining time is 5min. After refining, the pretreatment of the electrolytic aluminum liquid is completed by standing for 10min. To avoid one bag being insufficient, prepare another bag #2 and repeat the above method of taking out the molten aluminum until the required amount is reached. The weight of the molten aluminum in bag #2 is 10.3t. Use argon gas to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of sodium-free two-in-one powder refining agent and sodium-free granular refining agent is 1:1. The total amount of refining agent is 15.4kg. The refining time is 5min. After refining, let it stand for 10min to complete the pretreatment of the electrolytic aluminum liquid.

[0106] S3. Ingredients:

[0107] During the charging process of the smelting furnace, 14t was loaded according to the plan.

[0108] Add 1 / 5 of the weight of the aluminum liquid in the 1# bag to the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.6t);

[0109] Add 1 / 5 of the weight of the aluminum liquid in the 2# ladle to the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.49t);

[0110] The planned total furnace load is 14t. The melting furnace is charged with solid materials, which consist of 4t of Al99.80 remelted aluminum ingots and 3t of 8079 alloy cast and rolled sheet scrap. Spare molten aluminum is then added, and 5.5t of molten aluminum from the 1# ladle is added to the target melting furnace. Because one bag of qualified spare molten aluminum is insufficient, 1.5t of molten aluminum from the 2# ladle is added to the target melting furnace. The actual furnace load is 14t, with solid materials accounting for 50%;

[0111] S4. Adjust the composition of the aluminum liquid:

[0112] During the process of adjusting the composition of the molten aluminum in the smelting furnace, aluminum-iron master alloy, aluminum-titanium master alloy, aluminum-copper master alloy, Al-Re master alloy and aluminum-silicon master alloy are used to adjust the molten aluminum in the smelting furnace to the following composition by mass percentage: Fe: 0.90%, Si: 0.10%, Ti: 0.035%, Cu: 0.030%, Re: 0.08%, Mn: 0.01%, impurity elements Ca: 0.010%, V: 0.006%, and the balance is Al. Except for the Ti content, the contents of other elements are adjusted to the correct content in the smelting furnace.

[0113] S5. Alloy melting:

[0114] (1) Refining in smelting furnace:

[0115] After the charge in the smelting furnace is completely melted, the temperature of the aluminum liquid is raised to 725℃, and the aluminum liquid is electromagnetically stirred for 10 minutes. When the melt temperature reaches 730℃, refining begins. The sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 28kg. The sodium-free remelting granular refining agent is evenly loaded into the aluminum liquid using argon gas. The refining time is 26 minutes. After standing for 35 minutes, the slag is skimmed. The converter temperature of the smelting furnace melt is 755℃. After the smelting furnace temperature and composition meet the control requirements, the converter is turned on.

[0116] (2) Refining in a static furnace:

[0117] The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar+sodium-free environmentally friendly refining agent and the refining agent dosage. For the remaining refining, 0.4-0.6% of the total mass of the melt in the furnace is added before each refining, and high-purity argon is used for refining.

[0118] During the process of transferring the melt from the converter to the static furnace, AlTi10 alloy is evenly poured into the molten aluminum from the chute twice. The amount of AlTi10 alloy added is 0.8‰ of the weight of the molten aluminum. During the continuous production process, the converter liquid level in the static furnace is maintained at 350mm.

[0119] S6. Online processing:

[0120] The melt obtained from S4 was processed online. The Al-Ti5-B1 ​​grain refiner was preheated and added at the degassing box inlet. The addition amount was 0.18% of the aluminum liquid throughput. The Al-Ti5-B1 ​​wire rod temperature after preheating was 400°C, and the temperature of the melt at the addition point was 723°C. The online Ti increment was controlled at 0.008%.

[0121] After flowing out of the degassing box, the aluminum liquid enters the filtration system, which adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series;

[0122] The degassing box uses a silicon nitride rotor for online degassing. The online refining gas is argon, with a working gas pressure of 0.55 MPa, a flow rate of 15 L / Min, and a cover gas flow rate of 20 L / Min.

[0123] The series double filtration system uses a 40PPI+60PPI ceramic filter plate (CFF) for the first stage and a 16PPI tubular filter (MCF) for the second stage. The outlet temperature of the tubular filter is 715°C. The temperature drop of the aluminum liquid at the furnace eye, degassing box outlet, tubular filter outlet and front box is no more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is 0.100ml / 100g·Al.

[0124] S7, Casting and Rolling:

[0125] The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spray roller surface lubrication process is adopted. The wall thickness of the roller sleeve is 35mm, the casting and rolling zone is 65mm long, the front box temperature is controlled at 700-705℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 850mm / min, the cooling water temperature is 32℃, and the cooling water flow rate is 130m 3 / h, obtaining a cast strip with a thickness of 7.5mm and a center crown of 0.03mm. The temperature of the cast strip before coiling is 127℃, and cold rolling production begins after the coil temperature reaches 39℃;

[0126] S8, cold rolling:

[0127] The cast strip obtained by S7 is cold rolled to 4.0mm in one pass, and the rolling speed is controlled at 400m / min, and then homogenized annealing is carried out. After the coil temperature reaches 560℃, a bipolar homogenization annealing process of 560℃ / 10h+530℃ / 6h is adopted. After the annealing is completed, the coil is cooled to 290℃ with the furnace and then air-cooled. After the coil temperature is lower than 40℃, the strip is thinned from 4.0mm to 0.6mm by three passes, and the processing rate of each pass is controlled at 40-60%. After trimming, intermediate annealing is carried out, and the annealing process is 320℃ / 6h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6mm to the finished product thickness of 0.26mm, the tensile strength is 145MPa, and the elongation (A 50 ) is 3%, and the 8079 alloy double zero foil billet is processed. The rolling oil transmittance during the intermediate rolling process is 98.1%, and the surface roughness of the finished billet is Ra0.3μm.

[0128] Example 3:

[0129] A method for preparing 8079 double-zero aluminum foil blank using electrolytic aluminum liquid comprises the following steps:

[0130] S1. Screening of qualified electrolytic aluminum liquid:

[0131] By screening the state of the electrolytic cell, we selected electrolytic aluminum liquid with relatively pure melt as the raw material for double-zero foil billets. The optimal working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.85V, the peak value of the working voltage fluctuation in the past three months is 0.6V, and the cell temperature is 939℃. The electrolytic aluminum liquid that meets the requirements is selected from the source of aluminum electrolysis as the raw material: the mass percentage of Fe in the electrolytic aluminum liquid is 0.10%, the mass percentage of Si is 0.05%, and the content of Na is 60ppm.

[0132] S2. Pretreatment of electrolytic aluminum liquid:

[0133] The electrolytic aluminum liquid obtained by S1 screening is loaded into a vacuum ladle and refined by powder spraying in the ladle. The weight of the aluminum liquid in the 1# ladle is 10.2t. Argon is used to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent is 1:1. The total amount of refining agent is 10kg. The refining time is 4min. After refining, it is allowed to stand for 8min to complete the pretreatment of the electrolytic aluminum liquid. To avoid one bag being insufficient, prepare another 2# bag and repeat the above aluminum liquid taking method until the required amount is reached. The aluminum liquid in the 2# bag weighs 9.6t. Use argon gas to spray the refining agent into the electrolytic aluminum liquid. The refining agent is composed of a uniform mixture of sodium-free two-in-one powder refining agent and sodium-free granular refining agent. The weight percentage of sodium-free two-in-one powder refining agent and sodium-free granular refining agent is 1:1. The total amount of refining agent is 11.5kg. The refining time is 3 minutes. After refining, let it stand for 7 minutes to complete the pretreatment of the electrolytic aluminum liquid.

[0134] S3. Ingredients:

[0135] During the charging process of the smelting furnace, 16t was loaded according to the plan.

[0136] Add 1 / 5 of the weight of the aluminum liquid in the 1# ladle into the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.44t);

[0137] Add 1 / 5 of the weight of the aluminum liquid in the 2# ladle into the melting furnace of other products with lower aluminum liquid quality requirements, and then use the upper 2 / 3 of the remaining aluminum liquid as qualified spare aluminum liquid for double zero foil billets (5.12t);

[0138] The planned total furnace load was 16 tons. The melting furnace was charged with solid materials, including 4.2 tons of Al99.80 remelted aluminum ingots and 2.2 tons of 8079 alloy cast and rolled sheet scrap. Spare molten aluminum was then added, and 5.4 tons of molten aluminum from the 1# ladle was added to the target melting furnace. Because one bag of qualified spare molten aluminum was insufficient, 4.1 tons of molten aluminum from the 2# ladle was added to the target melting furnace. The actual charge was 15.9 tons, with solid materials accounting for 40.3% of the total.

[0139] S4. Adjust the composition of the molten aluminum:

[0140] During the process of adjusting the composition of the molten aluminum in the smelting furnace, aluminum-iron master alloy, aluminum-titanium master alloy, aluminum-copper master alloy, Al-Re master alloy and aluminum-silicon master alloy are used to adjust the molten aluminum in the smelting furnace to the following composition by mass percentage: Fe: 0.81%, Si: 0.14%, Ti: 0.035%, Cu: 0.027%, Re: 0.05%, Mn: 0.018%, impurity elements Ca: 0.009%, V: 0.011, and the balance is Al. Except for the Ti content, the contents of other elements are adjusted to the correct content in the smelting furnace.

[0141] S5. Alloy melting:

[0142] (1) Refining in smelting furnace:

[0143] After the charge in the smelting furnace is completely melted, the temperature of the aluminum liquid is raised to 725°C, and the aluminum liquid is electromagnetically stirred for 10 minutes. When the melt temperature reaches 730°C, refining begins. The sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 22.3 kg. The sodium-free remelting granular refining agent is evenly loaded into the aluminum liquid using argon gas. The refining time is 26 minutes. After standing for 30 minutes, the slag is skimmed. The converter temperature of the smelting furnace melt is 745°C. After the smelting furnace temperature and composition meet the control requirements, the converter is turned on.

[0144] (2) Refining in a static furnace:

[0145] The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar+sodium-free environmentally friendly refining agent and the refining agent dosage. For the remaining refining, 0.4-0.6% of the total mass of the melt in the furnace is added before each refining, and high-purity argon is used for refining.

[0146] During the process of transferring the melt from the converter to the static furnace, AlTi10 alloy is evenly added to the molten aluminum twice through the chute. The amount of AlTi10 alloy added is 0.8‰ of the weight of the molten aluminum. During continuous production, the converter liquid level in the static furnace is maintained at 320mm. This step can prevent the concentrated outflow of overburned melt caused by a low liquid level, which deteriorates the grain structure of the billet, and prevents the large-scale agitation of precipitated inclusions at the bottom of the furnace.

[0147] S6. Online processing:

[0148] The melt obtained from S4 was processed online. The Al-Ti5-B1 ​​grain refiner was preheated and added at the degassing box inlet. The addition amount was 0.15% of the aluminum liquid throughput. The temperature of the preheated Al-Ti5-B1 ​​wire rod was 490°C, and the temperature of the melt at the addition point was 727°C. The online Ti increment was controlled at 0.008%.

[0149] After flowing out of the degassing box, the aluminum liquid enters the filtration system, which adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series;

[0150] The degassing box uses a silicon nitride rotor for online degassing. The online refining gas is argon, with a working gas pressure of 0.25 MPa, a flow rate of 13 L / Min, and a cover gas flow rate of 16 L / Min.

[0151] The series double filtration system uses a 40PPI+60PPI ceramic filter plate (CFF) for the first stage and a 16PPI tubular filter (MCF) for the second stage. The outlet temperature of the tubular filter is 713°C. The temperature drop between the furnace eye, degassing box outlet, tubular filter outlet, and aluminum liquid in the front box is no more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is 0.096ml / 100g·Al.

[0152] S7, Casting and Rolling:

[0153] The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spray roller surface lubrication process is adopted. The wall thickness of the roller sleeve is 50mm, the casting and rolling zone is 65mm long, the front box temperature is controlled at 695℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 750mm / min, the cooling water temperature is 32℃, and the cooling water flow rate is 130m 3 / h, obtaining a cast strip with a thickness of 7.5mm and a center crown of 0.03mm. The temperature of the cast strip before coiling is 147℃, and cold rolling production begins when the coil temperature reaches 39℃.

[0154] S8, cold rolling:

[0155] The cast strip obtained by S7 is cold rolled to 4.0mm in one pass, and the rolling speed is controlled at 380m / min, and then homogenized annealing is carried out. After the coil temperature reaches 560℃, a bipolar homogenization annealing process of 560℃ / 10h+530℃ / 6h is adopted. After the annealing is completed, the coil is cooled to 280℃ with the furnace and then air-cooled. After the coil temperature is lower than 40℃, the strip is thinned from 4.0mm to 0.6mm by three rolling passes, and the processing rate of each pass is controlled at 40-60%. After trimming, intermediate annealing is carried out, and the annealing process is 320℃ / 6h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6mm to the finished product thickness of 0.24mm, the tensile strength is 138MPa, and the elongation (A 50 ) is 4.1%, and the 8079 alloy double zero foil billet is processed. The rolling oil transmittance during the intermediate rolling process is 99.2%, and the surface roughness of the finished billet is Ra0.36μm.

Claims

1. A method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid, characterized in that The steps include: S1. Screening of qualified electrolytic aluminum liquid: Screening the electrolytic aluminum liquid that meets the requirements from the source of aluminum electrolysis as raw materials: the mass percentage of Fe in the electrolytic aluminum liquid is ≤ 0.13%, the mass percentage of Si is ≤ 0.05%, and the content of Na is ≤ 60ppm; S2. Pretreatment of electrolytic aluminum liquid: The electrolytic aluminum liquid obtained by S1 screening is placed in a vacuum ladle, and the refining agent is sprayed into the electrolytic aluminum liquid using argon gas by adopting the method of powder spraying in the ladle. The electrolytic aluminum liquid is then allowed to stand for a period of time to complete the pretreatment of the electrolytic aluminum liquid. S3. Ingredients: First, take out the upper layer of aluminum liquid in the vacuum ladle in S2, which accounts for 1 / 5 of the total amount of electrolytic aluminum liquid, and then take out the upper 2 / 3 of the remaining electrolytic aluminum liquid in the vacuum ladle. If one bag is not enough, repeat the aluminum liquid taking method in S2-S3 until the required amount is reached, and obtain the spare aluminum liquid for double-zero foil billet; Charge the smelting furnace with solid materials first, then add the spare aluminum liquid. The weight of the solid materials should be controlled at 30-50% of the total weight of the materials. S4. Adjust the composition of the aluminum liquid: The aluminum liquid in the smelting furnace is adjusted to have the following composition by mass percentage: Fe 0.70-0.90%, Si 0.10-0.20%, Ti 0.015-0.035%, Cu 0.015-0.030%, Re 0.05-0.08%, Mn ≤ 0.03%, other impurities ≤ 0.15%, and the balance is Al; S5. Alloy melting: (1) Refining in the smelting furnace: After the charge in the smelting furnace is completely melted, the temperature of the molten aluminum is raised to 725°C, and the molten aluminum is electromagnetically stirred for 10-15 minutes. When the melt temperature reaches 730°C, refining begins. Sodium-free remelting granular refining agent is used for melt refining. The amount of refining agent is 1.5-2.0kg / t·Al. Argon is used to evenly load the sodium-free remelting granular refining agent into the molten aluminum. The refining time is 22-26 minutes. After standing for 20-35 minutes, slag is skimmed. The converter temperature of the smelting furnace melt is 740-755°C. The converter is started after the smelting furnace temperature and composition meet the control requirements. (2) Refining in a static furnace: The melt is transferred from the converter to the static furnace, and the aluminum liquid is kept at a temperature of 740-750℃ to ensure that the aluminum liquid temperature at the furnace eye is controlled at 730±3℃. The aluminum liquid is refined every 5 hours after being transferred from the converter to the static furnace. The first refining uses Ar + sodium-free environmentally friendly refining agent with a refining agent dosage of 0.8-1.2kg / t·Al. Before each refining, 0.4-0.6% of the total mass of the melt in the furnace is added with aluminum ingots or cast-rolled aluminum plates of the same alloy. High-purity argon is used for refining. S6. Online processing: The melt obtained from S4 is processed online. The Al-Ti5-B1 ​​grain refiner is preheated and added at the degassing box inlet. The addition amount is 0.12-0.18% of the aluminum liquid passing through. The temperature of the preheated Al-Ti5-B1 ​​wire rod is not less than 400°C, and the temperature of the melt at the addition point is not less than 720°C. The online Ti increment is controlled at 0.005-0.008%. After flowing out of the degassing box, the aluminum liquid enters the filtration system. The filtration system adopts a double filtration system of foam ceramic filter plate + ceramic filter tube in series. The first stage of the double filtration system adopts 40PPI+60PPI ceramic filter plate, and the second stage adopts 16PPI tubular filter. The outlet temperature of the tubular filter is 710-715°C. The temperature drop of the aluminum liquid at the furnace eye, degassing box outlet, tubular filter outlet and front box outlet is not more than 10°C. The hydrogen content of the melt at the outlet of the tubular filter is not higher than 0.110ml / 100g·Al. S7, Casting and Rolling: The casting and rolling adopts a double-roll inclined casting and rolling mill. The upper and lower rollers of the casting and rolling mill are made of alloy steel roller sleeves, and the graphite spraying roller surface lubrication process is adopted. The casting and rolling area is 58-65mm long, the front box temperature is controlled at 695-705℃, the casting nozzle adopts two-level diversion, the casting and rolling speed is 750-850mm / min, the cooling water temperature is 32-35℃, and the cooling water flow rate is 100-130m 3 / h, to obtain cast and rolled strip with a thickness of 7.0-7.5mm and a center crown of 0.02-0.03mm. The temperature of the cast and rolled strip before coiling shall not be higher than 150℃, and cold rolling production shall begin after the coil temperature is lower than 40℃. S8, cold rolling: The cast strip obtained in S7 is cold rolled to 4.0 mm in one pass at a rolling speed of 200-400 m / min, and then homogenized annealing is performed. After the coil temperature reaches 560°C, a bipolar homogenization annealing process of 560°C / 10 h + 530°C / 6 h is adopted. After the annealing is completed, the coil is cooled with the furnace to a temperature below 300°C and then air-cooled. After the coil temperature is below 40°C, the strip is thinned from 4.0 mm to 0.6 mm in three passes, with the processing rate of each pass controlled at 40-60%. After trimming, intermediate annealing is performed at 320°C / 6 h. After intermediate annealing, cold rolling is continued, and then rolled to H14 state in one pass, so that the strip thickness is thinned from 0.6 mm to a finished thickness of 0.22-0.26 mm. The tensile strength is 135-145 MPa, and the elongation is 3-5%. The processing of 8079 alloy double zero foil blank is completed.

2. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 1, characterized in that: As described in S1, the electrolytic aluminum liquid that meets the requirements is screened from the aluminum electrolysis source as raw material, the working voltage of the electrolytic cell corresponding to the selected electrolytic aluminum liquid is 3.85-3.95V, the peak value of the working voltage fluctuation in the past three months is ≯0.6V, and the cell temperature is 930-940℃.

3. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 2, characterized in that: The refining agent in S2 is composed of a uniform mixture of a sodium-free two-in-one powder refining agent and a sodium-free granular refining agent, the weight percentage of the sodium-free two-in-one powder refining agent and the sodium-free granular refining agent is 1:1, the total amount of the refining agent is 0.5-1.5 kg / t·Al, the refining time is 3-5 minutes, and the agent is allowed to stand for 5-10 minutes after refining.

4. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 3, characterized in that: The solid materials in S3 are Al99.80 remelted aluminum ingots and 8079 alloy cast and rolled plate scraps.

5. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 4, characterized in that: The smelting cycle of the smelting furnace in (1) of S5 is not more than 9 hours.

6. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 5, characterized in that: In (2) of S5, during the process from the melt converter to the static furnace, AlTi10 alloy is evenly flushed into the aluminum liquid from the chute twice. The amount of AlTi10 alloy added is 0.8‰ of the weight of the aluminum liquid. During the continuous production process, the converter liquid level in the static furnace is not less than 300mm.

7. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 6, characterized in that: The degassing box in S6 uses a silicon nitride rotor for online degassing, the online refining gas is argon, the working gas pressure is 0.20-0.55 MPa, the flow rate is 4-15 L / Min, and the covering gas flow rate is 10-20 L / Min.

8. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 7, characterized in that: The wall thickness of the roller sleeve in S7 is 35-50 mm.

9. The method for preparing 8079 double zero aluminum foil blank using electrolytic aluminum liquid as claimed in claim 8, characterized in that: During the rolling process described in S8, the light transmittance of the rolling oil is not less than 98%, and the surface roughness of the finished product billet is Ra0.3-0.4μm.