Aluminum electrolysis method for 500KA aluminum electrolysis cell

Abstract

The invention relates to the technical field of electrolytic aluminum, and particularly discloses an aluminum electrolysis method of a 500KA aluminum electrolysis cell, which comprises the following steps: (1) anode carbon block selection; (2) electrolyte composition; (3) charging; and (4) starting roasting. The aluminum electrolysis method for the 500KA aluminum electrolysis cell has the beneficial effects that the carbon residue amount in the aluminum electrolysis process of the aluminum electrolysis cell is effectively reduced, and 30% of hazardous waste is reduced specifically when 1 ton of aluminum is produced; the consumption of the anode carbon block is reduced, specifically, the consumption of the anode carbon block is reduced by 2% when one ton of aluminum is produced, the casting amount of phosphorus pig iron molten iron between the steel claw and the anode carbon block is reduced, specifically, the consumption of phosphorus pig iron is reduced by 27% when one ton of aluminum is produced, the primary crystal temperature of electrolyte is reduced, meanwhile, the emission of fluoride gas in the electrolysis process is reduced, and environmental pollution is avoided; and moreover, the solubility of the aluminum oxide and the conductivity of the electrolyte are improved, the current efficiency of the electrolytic aluminum is effectively improved, and the aluminum quality of the produced electrolytic aluminum is relatively high and can reach Al99.95.

Description

Technical Field

[0001] This invention patent relates to the technical field of electrolytic aluminum, and specifically relates to an electrolytic aluminum method for a 500KA aluminum electrolysis cell. Background Art

[0002] Electrolytic aluminum is an important basic raw material, widely used in industries such as aerospace, automotive, construction, and packaging. It is a pure aluminum prepared by electrolysis using alumina (Al2O3) as the raw material. Currently, there are multiple models of the main equipment for electrolytic aluminum, namely electrolysis cells. Among them, the 500KA electrolysis cell is a large-capacity and high-power-density electrolytic aluminum device, mainly used for large-scale production of electrolytic aluminum. It has a high current output capacity and can complete a large amount of aluminum metal extraction in a short time, thus meeting the requirements of modern industry for high performance and high efficiency. During the electrolysis of aluminum, the 500KA electrolysis cell reduces alumina to aluminum metal through electrolysis. As a high-performance and high-efficiency electrolytic aluminum device, the 500KA electrolysis cell can effectively improve the production efficiency and quality of aluminum metal, and also has good energy-saving effects, so it has been widely used in modern industry.

[0003] However, currently, the 500KA electrolytic cell can only produce Al99.85 products of the highest standard, and the quality of the produced aluminum is relatively low. To address the above problems, the following existing patent No. 201810786374.9 discloses a method for producing high-quality Al99.90 products using a 500kA aluminum electrolytic cell; by improving the specific technological steps of aluminum electrolysis production, controlling the content of impurities such as iron and silicon, increasing the proportion of alumina in the anode sealing and the crust covering material, enhancing the iron removal effect on crushed materials, using high-quality dry fluoride salts, adopting the technological conditions of aluminum electrolysis production resistant to temperature changes, stably maintaining the thickness of the furnace lining and the electrolyte level, using a pollution-free alumina anode steel claw protection ring, and adopting the technology of special tapping, mixing furnace and casting equipment, high-quality products with a purity above Al99.90 are produced; however, there are still the following problems: 1. The content of the impurity element vanadium in the anode carbon block in the above patent is relatively high and the sodium content is relatively low, and its air permeability is not limited. The high vanadium content leads to an increase in the separated carbon slag in the electrolytic cell, so the labor intensity of workers for cleaning is high, and it also results in a large amount of hazardous waste to be treated and a high cost for hazardous waste treatment; the low sodium content affects the conductivity of the anode carbon block, thus reducing the efficiency of aluminum electrolysis; at the same time, too high air permeability will cause a large amount of slag falling in the anode carbon block during the aluminum electrolysis process, and it will also increase the resistivity of the anode carbon block, affecting the current efficiency of the electrolysis process; 2. The electrolyte in the above patent selects conventional fluoride salts (sodium fluoride and aluminum fluoride). During the electrolysis process, the electrolysis temperature is a very important technical parameter. The electrolysis temperature refers to the temperature of the electrolyte, which is a temperature range, generally taking 950 - 970°C, approximately 20 - 30°C higher than the initial crystallization point of the electrolyte. Among them, the melting point of aluminum is 660°C. If liquid aluminum is to be produced, the electrolysis temperature only needs to be 100 - 150°C higher than the melting point of aluminum. In other words, the ideal electrolysis temperature should be between 750 - 800°C. However, the initial crystallization point of the above fluoride salt electrolyte is relatively high, so the electrolysis temperature is also correspondingly high, which in turn leads to an increase in the dissolution loss of aluminum in the electrolytic cell, a decrease in the current efficiency, and an increase in the consumption of electric energy and materials, which is unfavorable for production; 3. The depth of the carbon bowl in the existing anode carbon block is 130mm, and carbon needles with a height of 15mm are arranged at the bottom of the carbon bowl. After the steel claw is put in, phosphor cast iron is cast. The service life cycle of the above anode carbon block is relatively short, only 35 days, and the annual consumption of the anode carbon block is large, increasing the production cost of the enterprise; at the same time, since phosphor cast iron also needs to be cast in the carbon bowl at the bottom of the steel claw, the amount of phosphor cast iron molten iron poured between the steel claw and the anode carbon block is large. 0.0015t of phosphor cast iron molten iron is required for each ton of aluminum produced, and thus the melting amount of phosphor cast iron and the power consumption for melting phosphor cast iron are relatively high. Summary of the Invention

[0004] In view of this, the object of the present invention is to provide an aluminum electrolysis method for a 500KA aluminum electrolysis cell. The preparation method provided by the present invention effectively reduces the amount of carbon slag during the aluminum electrolysis process in the aluminum electrolysis cell. Specifically, the generation of hazardous waste is reduced by 30% during the production of 1 ton of aluminum; at the same time, the intensity of workers' salvaging and cleaning the electrolyte surface is reduced; and the consumption of anode carbon blocks is reduced. Specifically, the consumption of anode carbon blocks is reduced by 2% during the production of 1 ton of aluminum, and the amount of phosphor cast iron molten iron casting between the steel claws and the anode carbon blocks is reduced. Specifically, the consumption of phosphor cast iron is reduced by 27% during the production of 1 ton of aluminum, and the primary crystallization temperature of the electrolyte is reduced. Therefore, the electrolysis temperature during the aluminum electrolysis process can be significantly reduced, effectively reducing the power consumption; at the same time, the emission of fluoride gas during the electrolysis process is reduced, avoiding environmental pollution; moreover, the solubility of alumina and the conductivity of the electrolyte are increased, effectively improving the current efficiency of aluminum electrolysis, ensuring that the aluminum quality of the produced electrolytic aluminum is relatively high, and can reach Al99.95.

[0005] The technical solution of the present invention discloses an aluminum electrolysis method for a 500KA aluminum electrolysis cell, which includes the following steps: (1) Selection of anode carbon block: The anode carbon block meets the first-class product standard. The impurity content in the anode carbon block is Fe≤250ppm, Si≤230ppm, S≤2.0%, V≤250ppm, 210≤Na≤300ppm, and the air permeability of the anode carbon block≤2npm; (2) Electrolyte: It is composed of the following components by weight percentage, 11-23% of Na3AlF6, 15-20% of aluminum fluoride, 2-3% of cryolite-potassium, 10-23% of polypyrrole, 13%-24% of polyvinyl alcohol, and 6-10% of alumina; Among them, a complex is formed when polypyrrole is mixed with alumina. The lattice structure of alumina in this complex is affected by polypyrrole molecules, improving the ion channels inside the crystal; in addition, polypyrrole can also be adsorbed on the surface of alumina to form an interfacial layer, further promoting the dissolution reaction and the dissolution of alumina; polyvinyl alcohol can be used as an excellent carrier for alumina, enhancing its solubility in the electrolyte; after adding cryolite-potassium, as the potassium concentration increases, the solubility of A1203 in the electrolyte also increases. (3) Furnace charging: First, hang the anode carbon block in step (1) on the 500kA aluminum electrolysis cell, then place the electrolyte in step (2) in the 500kA aluminum electrolysis cell until it reaches the lower surface of the anode carbon block, and finally cover the anode carbon block surface with alumina covering material; (4)Baking and startup: Bake the 500kA aluminum electrolysis cell in step (3) by means of gas combustion. The baking time is 96 - 105h. When the baking temperature reaches 850℃ - 910℃, add the electrolyte solution into the aluminum electrolysis cell. After the depth of the anode carbon block immersed in the electrolyte reaches 12 - 18cm, power on. When all the materials in the 500kA aluminum electrolysis cell are melted, fish out all the carbon slag, then turn on the automatic feeding of the cell control machine. After pouring in the liquid aluminum, the startup process of the entire aluminum electrolysis cell is completed.

[0006] Further, the anode carbon block in step (1) includes a carbon block body. On the upper surface of the carbon block body, a number of carbon bowls with a depth of 115mm are provided. On the side wall of the carbon bowl, a number of inclined grooves arranged in parallel are provided.

[0007] Further, the included angle between the inclined groove and the axis of the carbon bowl is 15 - 30°.

[0008] Further, the primary crystallization temperature of the electrolyte in step (2) is 680 - 740℃.

[0009] Further, in step (4), the voltage control process after power on: maintain the voltage at 5.5 - 6.5V for 8 - 10 hours, maintain the voltage at 4.7 - 5.5V for 8 - 10 hours, and maintain the voltage at 4.11 - 4.7V for 8 - 10 hours.

[0010] Further, after step (4), it also includes the stable production of electrolytic aluminum: control the voltage at 3.79 - 3.83V, the superheat at 6 - 9℃, the electrolyte level at 16 - 18cm, the aluminum level at 20 - 23cm, the covering material at 3 - 5cm, and the electrolysis temperature at 890 - 920℃.

[0011] Advantages of the present invention: 1. The present invention discloses an aluminum electrolysis method for a 500KA aluminum electrolysis cell. By controlling the V content, Na content, and air permeability in the anode carbon block, the amount of carbon slag in the aluminum electrolysis process of the aluminum electrolysis cell is effectively reduced. Specifically, the generation of hazardous waste is reduced by 30% per ton of aluminum produced, and thus the cost of treating hazardous waste is reduced by 1.1116 million yuan per year. At the same time, the intensity of workers fishing and cleaning the electrolyte surface is reduced. And the consumption of the anode carbon block is reduced. Specifically, the consumption of the anode carbon block is reduced by 2% per ton of aluminum produced, and thus the cost of purchasing the anode carbon block is reduced by 6.4785 million yuan per year.

[0012] 2. The present invention discloses an aluminum electrolysis method for a 500KA aluminum electrolysis cell. By removing the carbon nails in the carbon bowl of the anode carbon block and reducing the depth of the carbon bowl to 115mm, the height of the anode carbon block participating in the aluminum electrolysis production is effectively increased, and the service life of each anode carbon block is improved. At the same time, the amount of ferrophosphorus molten iron cast between the steel claw and the anode carbon block is reduced. Specifically, the consumption of ferrophosphorus is reduced by 27% for producing 1 ton of aluminum, thereby reducing the melting amount of ferrophosphorus and the power consumption for melting ferrophosphorus.

[0013] 3. The present invention discloses an aluminum electrolysis method for a 500KA aluminum electrolysis cell. By adding cryolite potassium, polypyrrole and polyvinyl alcohol to the electrolyte, the usage amounts of Na3AlF6 and aluminum fluoride are reduced, thereby reducing the primary crystallization temperature of the electrolyte. Therefore, the electrolysis temperature during the aluminum electrolysis process can be significantly reduced, effectively reducing the power consumption. At the same time, the emission of fluoride gas during the electrolysis process is reduced, avoiding environmental pollution. Moreover, the solubility of alumina and the conductivity of the electrolyte are increased, effectively improving the current efficiency of the electrolytic aluminum.

[0014] 4. The present invention discloses an aluminum electrolysis method for a 500KA aluminum electrolysis cell. The polypyrrole and polyvinyl alcohol introduced into the electrolyte do not contain metal impurities, thereby avoiding the problem that the impurities in the electrolyte will reduce the aluminum purity. At the same time, the content of impurities such as ferrosilicon in the anode carbon block is relatively low, thereby avoiding the entry of its impurities into the aluminum liquid and affecting the aluminum purity, ensuring that the aluminum quality of the produced electrolytic aluminum is relatively high and can reach Al99.95. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 It is a schematic structural diagram of the anode carbon block of the present invention.

[0016] Carbon block body 1, carbon bowl 11, inclined groove 12. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0017] The present invention will be further described in detail below through embodiments.

[0018] Embodiment 1: An aluminum electrolysis method for a 500KA aluminum electrolysis cell, which includes the following steps: (1) Selection of anode carbon block: The anode carbon block meets the first-class product standard. The impurity contents in the anode carbon block are Fe 220ppm, Si 200ppm, S 2.0%, V 230ppm, Na 240ppm, and the air permeability of the anode carbon block is 1.8npm. The anode carbon block includes a carbon block body 1. A plurality of carbon bowls 11 with a depth of 115mm are provided on the upper surface of the carbon block body 1. A plurality of inclined grooves 12 arranged in parallel are provided on the side wall of the carbon bowl 11 to strengthen the connection between the cast ferrophosphorus and the carbon bowl 11. The included angle between the inclined groove 12 and the axis of the carbon bowl 11 is 20°.

[0019] (2) Electrolyte: It is composed of the following components by weight percentage: 17% of Na3AlF6, 17% of aluminum fluoride, 2.5% of cryolite-potassium, 16% of polypyrrole, 18% of polyvinyl alcohol, and 8% of alumina. The performance of the electrolyte in this example was measured, and the results were as follows: The primary crystallization temperature of the electrolyte in this example was 680 °C.

[0020] (3) Furnace charging: First, hang the anode carbon block in step (1) on a 500 kA aluminum electrolysis cell, then place the electrolyte in step (2) in the 500 kA aluminum electrolysis cell until it reaches the lower surface of the anode carbon block, and finally cover the surface of the anode carbon block with alumina covering material; (4) Baking and startup: Bake the 500 kA aluminum electrolysis cell in step (3) by means of gas combustion. The baking time is 100 h. When the baking temperature reaches 870 °C, add the electrolyte liquid to the aluminum electrolysis cell. After the depth of the anode carbon block immersed in the electrolyte reaches 14 cm, power on. Keep the voltage at 6 V for 9 hours, 5 V for 9 hours, and 4.5 V for 9 hours; When all the materials in the 500 kA aluminum electrolysis cell are melted, clean up the carbon slag, then turn on the automatic feeding of the cell control machine. After pouring in the liquid aluminum, the startup process of the entire aluminum electrolysis cell is completed.

[0021] (5) Stable production of electrolytic aluminum: Control the voltage at 3.80 V, the superheat at 7 °C, the electrolyte level at 17 cm, the aluminum level at 21 cm, the covering material at 4 cm, and the electrolysis temperature at 890 °C. Among them, the DC power consumption of this furnace was 11799 kW▪h / t—Al, the current efficiency reached 96%, and the purity of the produced aluminum liquid reached 99.95%.

[0022] Example 2: An aluminum electrolysis method for a 500 KA aluminum electrolysis cell, which includes the following steps: (1) Selection of anode carbon block: The anode carbon block meets the first-class product standard. The impurity contents in the anode carbon block are Fe at 240 ppm, Si at 220 ppm, S at 1.8%, V at 240 ppm, and Na at 210 ppm. The air permeability of the anode carbon block is 1.9 npm; The anode carbon block includes a carbon block body 1. On the upper surface of the carbon block body 1, several carbon bowls 11 with a depth of 115 mm are provided. On the side wall of the carbon bowl 11, several inclined grooves 12 are provided in parallel to strengthen the connection between the cast phosphor iron and the carbon bowl 11; The included angle between the inclined groove 12 and the axis of the carbon bowl 11 is 30°.

[0023] (2) Electrolyte: It is composed of the following components by weight percentage: 23% of Na3AlF6, 20% of aluminum fluoride, 3% of cryolite-potassium, 23% of polypyrrole, 24% of polyvinyl alcohol, and 10% of alumina. The primary crystallization temperature of the electrolyte is 740 °C.

[0024] (3) Furnace charging: First, hang the anode carbon block in step (1) on a 500 kA aluminum electrolysis cell. Then, place the electrolyte in step (2) in the 500 kA aluminum electrolysis cell until it reaches the lower surface of the anode carbon block. Finally, cover the surface of the anode carbon block with alumina covering material; (4) Baking and start-up: Bake the interior of the 500 kA aluminum electrolysis cell in step (3) by means of gas combustion. The baking time is 105 h. When the baking temperature reaches 910 °C, add electrolyte liquid to the aluminum electrolysis cell until the depth of the anode carbon block immersed in the electrolyte is 18 cm, then energize. Maintain at 6.5 V for 10 hours, 5.5 V for 10 hours, and 4.7 V for 10 hours. When all the materials in the 500 kA aluminum electrolysis cell are melted, fish out all the carbon slag. Then, turn on the automatic feeding of the cell control machine. After pouring in liquid aluminum, the start-up process of the entire aluminum electrolysis cell is completed.

[0025] (5) Stable production of electrolytic aluminum: Control the voltage at 3.83 V, the superheat at 9 °C, the electrolyte level at 18 cm, the aluminum level at 23 cm, the covering material at 5 cm, and the electrolysis temperature at 920 °C. The DC power consumption of this furnace is 11838 kW▪h / t—Al, the current efficiency reaches 94%, and the purity of the produced aluminum liquid reaches 99.92%.

[0026] Example 3: A method for electrolyzing aluminum in a 500 KA aluminum electrolysis cell, which includes the following steps: (1) Selection of anode carbon block: The anode carbon block meets the first-class product standard. The impurity contents in the anode carbon block are 250 ppm of Fe, 230 ppm of Si, 1.9% of S, 250 ppm of V, 300 ppm of Na, and the air permeability of the anode carbon block is 2 npm. The anode carbon block includes a carbon block body 1. On the upper surface of the carbon block body 1, a number of carbon bowls 11 with a depth of 115 mm are provided. On the side wall of the carbon bowl 11, a number of parallel oblique grooves 12 are provided to strengthen the connection between the cast phosphor iron and the carbon bowl 11. The included angle between the oblique groove 12 and the axis of the carbon bowl 11 is 15°.

[0027] (2) Electrolyte: It is composed of the following components by weight percentage, 11% of Na3AlF6, 15% of aluminum fluoride, 2% of cryolite, 10% of polypyrrole, 13% of polyvinyl alcohol, and 6% of alumina. The primary crystallization temperature of the electrolyte is 710 °C.

[0028] (3) Furnace charging: First, hang the anode carbon block in step (1) on a 500 kA aluminum electrolysis cell. Then, place the electrolyte in step (2) in the 500 kA aluminum electrolysis cell until it reaches the lower surface of the anode carbon block. Finally, cover the surface of the anode carbon block with alumina covering material; (4)Baking start-up: Bake the 500 kA aluminum electrolysis cell in step (3) by means of gas combustion. The baking time is 96 h. When the baking temperature reaches 850 °C, add the electrolyte liquid into the aluminum electrolysis cell. After the anode carbon block is immersed in the electrolyte to a depth of 12 cm, power on. Keep the voltage at 5.5 V for 8 hours, 4.7 V for 8 hours, and 4.11 V for 8 hours. When all the materials in the 500 kA aluminum electrolysis cell are melted, clean up the carbon slag. Then turn on the automatic feeding of the cell control machine. After pouring in the liquid aluminum, the start-up process of the entire aluminum electrolysis cell is completed.

[0029] (5)Stable production of electrolytic aluminum: Control the voltage at 3.79 V, the superheat at 6 °C, the electrolyte level at 16 cm, the aluminum level at 20 cm, the covering material at 3 cm, and the electrolysis temperature at 905 °C. The DC power consumption of this furnace is 11,820 kW▪h / t—Al, the current efficiency reaches 93%, and the purity of the produced aluminum liquid reaches 99.94%.

[0030] I. The method of producing high-quality Al99.90 products using the methods of Examples 1-3 of the present invention and the prior art patent No. 201810786374.9 which discloses a method for producing electrolytic aluminum in a 500 kA aluminum electrolysis cell. The results of the carbon slag amount, the consumed anode carbon block, and the consumed phosphor cast iron produced per ton of aluminum by the above several methods are shown in Table 1 below.

[0031] Table 1

[0032] As can be seen from Table 1 above, the method of Example 1 of the present invention is the best. The consumed anode carbon block per ton of aluminum produced is the least, and the amount of carbon slag produced is the least. Compared with the prior art, the present invention's Example 1 can reduce the generation of 30% of hazardous waste, reduce the consumption of 2% of the anode carbon block, and reduce the consumption of 27% of the phosphor cast iron per ton of aluminum produced.

[0033] II. The electrolytes disclosed in Examples 1-3 of the present invention and the prior art patent No. 201810786374.9 which discloses a method for producing high-quality Al99.90 products using a 500 kA aluminum electrolysis cell are respectively measured for electrolyte conductivity using the CVCC method. The detection device mainly includes a potentiostat (PGSTAT30) and a current booster (Booster20A). The detection results are shown in Table 2.

[0034] Table 2

[0035] As can be seen from Table 2, the electrolytes disclosed in Examples 1-3 of the present invention have higher conductivity compared with the prior art, and the electrolyte disclosed in Example 1 of the present invention has the highest conductivity.

[0036] III. The solubility of alumina in the electrolytes disclosed in Examples 1 - 3 of the present invention and in the method for producing high - quality Al99.90 products using a 500kA aluminum electrolytic cell disclosed in the prior - art patent No. 201810786374.9 was detected respectively. The specific method is as follows: The alumina rotating disk weighing method was used for determination. That is, the electrolytes disclosed in Examples 1 - 3 and in the prior art were heated into melts respectively. When the melt temperature was heated to a certain value, the sintered alumina disk rotated in the melt at a speed of 100 r / min. After rotation, the corundum disk was cleaned with a hot AlCl3 solution to remove the electrolyte on the corundum disk. According to the weight difference of the corundum disk, the saturated solubility of alumina was calculated. The results of the saturated solubility of alumina in the specific electrolytes are shown in Table 3 below.

[0037] Table 3

[0038] It can be seen from Table 3 that, compared with the electrolytes of the prior art, the solubility of alumina in the electrolytes disclosed in Examples 1 - 3 of the present invention is significantly higher, and the solubility of alumina in the electrolyte disclosed in Example 1 of the present invention is the highest.

[0039] The above are the preferred embodiments of the present invention. For those of ordinary skill in the art, without departing from the principle of the present invention, several improvements and refinements can be made, and these improvements and refinements should also be regarded as the protection scope of the present invention.

Claims

1. A method for aluminum electrolysis in a 500KA aluminum electrolysis cell, characterized in that, It includes the following steps: (1) Selection of anode carbon blocks: The anode carbon blocks meet the first-class product standard. The impurity contents in the anode carbon blocks are Fe ≤ 250 ppm, Si ≤ 230 ppm, S ≤ 2.0%, V ≤ 250 ppm, 210 ≤ Na ≤ 300 ppm, and the air permeability of the anode carbon blocks ≤ 2 npm; (2) Electrolyte: It is composed of the following components by weight percentage, 11 - 23% of Na3AlF6, 15 - 20% of aluminum fluoride, 2 - 3% of cryolite-potassium, 10 - 23% of polypyrrole, 13% - 24% of polyvinyl alcohol, and 6 - 10% of alumina; (3) Furnace charging: First, hang the anode carbon blocks in step (1) on a 500 kA aluminum electrolysis cell. Then, place the electrolyte in step (2) into the 500 kA aluminum electrolysis cell until it reaches the lower surface of the anode carbon blocks. Finally, cover the surface of the anode carbon blocks with alumina covering material; (4) Baking and startup: Bake the inside of the 500 kA aluminum electrolysis cell in step (3) by means of gas combustion. The baking time is 96 - 105 h. When the baking temperature reaches 850 °C - 910 °C, add electrolyte liquid into the aluminum electrolysis cell until the depth of the anode carbon blocks immersed in the electrolyte is 12 - 18 cm, and then power on. After all the materials in the 500 kA aluminum electrolysis cell are melted, fish out all the carbon slag. Then, turn on the automatic feeding of the cell control machine. After pouring in liquid aluminum, the startup process of the entire aluminum electrolysis cell is completed.

2. The aluminum electrolysis method of a 500KA aluminum electrolysis cell according to claim 1, characterized in that, The anode carbon blocks in step (1) include a carbon block body. On the upper surface of the carbon block body, a number of carbon bowls with a depth of 115 mm are opened. On the side wall of the carbon bowls, a number of inclined grooves are arranged in parallel.

3. The aluminum electrolysis method of a 500KA aluminum electrolysis cell according to claim 2, characterized in that, The included angle between the inclined grooves and the axis of the carbon bowls is 15 - 30°.

4. A method for aluminum electrolysis in a 500KA aluminum electrolytic cell according to claim 1, characterized in that, The primary crystallization temperature of the electrolyte in step (2) is 680 - 740 °C.

5. A method for aluminum electrolysis in a 500KA aluminum electrolysis cell according to claim 1, characterized in that, In step (4), the voltage control process after power on: Keep the voltage at 5.5 - 6.5 V for 8 - 10 hours, 4.7 - 5.5 V for 8 - 10 hours, and 4.11 - 4.7 V for 8 - 10 hours.

6. The aluminum electrolysis method for a 500KA aluminum electrolysis cell according to claim 1, characterized in that, After step (4), it also includes the stable production of electrolytic aluminum: Control the voltage at 3.79 - 3.83 V, the superheat at 6 - 9 °C, the electrolyte level at 16 - 18 cm, the aluminum level at 20 - 23 cm, the covering material at 3 - 5 cm, and the electrolysis temperature at 890 - 920 °C.

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