Method for prolonging service life of electrolytic cell based on composite material

Abstract

The invention discloses a method for prolonging the service life of an electrolytic cell based on a composite material. According to the invention, through the composite structure design of the gradient graphitization cathode and the silicon carbide reinforced phase, sodium permeation and thermal stress damage are effectively inhibited, the corrosion resistance of the cathode is improved by about 40%, and unplanned cell shutdown maintenance caused by lining damage is greatly reduced. The intelligent roasting starting technology is matched with the dynamic heat balance regulation and control system, the operation stability of the electrolytic cell is improved by 25% or above, the current efficiency is improved to 94.5%, the direct current consumption per ton of aluminum is directly reduced by about 120 kilowatt-hours, and the high energy consumption pain point of the electrolytic aluminum industry is remarkably relieved. The full-cycle material regeneration technology realizes that the resource utilization rate of the waste lining exceeds 85%, the annual operation and maintenance cost of a single tank is saved by nearly 20%, and an economic closed loop of the full life cycle of equipment is formed. Multi-physics field optimization and digital twinning technologies are fused, a technical standard system covering design, manufacturing and operation and maintenance is constructed, and electrolytic cell equipment is promoted to be iteratively upgraded towards the intelligent direction.

Description

Technical Field

[0001] The invention belongs to the technical field of electrolytic cells, and in particular relates to a method for extending the service life of an electrolytic cell based on a composite material. Background Art

[0002] In the modern industrial system, aluminum, as an important non-ferrous metal, is widely used in many fields such as construction, transportation, electronics, and packaging because of its many excellent properties such as light weight, high strength, good conductivity, and strong corrosion resistance. With the continuous development of the global economy and the rising demand for aluminum in various industries, the electrolytic aluminum industry occupies an increasingly critical position in the non-ferrous metal industry. In the production process of electrolytic aluminum, the electrolytic cell is the core equipment. Among them, the 530kA large prebaked electrolytic cell has been widely used in the current electrolytic aluminum industry due to its advantages such as high production capacity and relatively low energy consumption. However, the cell life of the electrolytic cell has always been an important factor restricting the efficient and stable development of the electrolytic aluminum industry. Extending the cell life of the electrolytic cell has many important significances. From an economic point of view, the construction and maintenance costs of the electrolytic cell are high. Extending the cell life can effectively reduce the frequency of equipment replacement, reduce fixed asset investment and maintenance costs, and thus improve the economic benefits of the enterprise.

[0003] However, the existing electrolytic cells have major defects such as poor resistance of cathode materials to sodium permeability, uneven distribution of thermal stress leading to structural damage, large temperature gradient during the roasting startup phase causing early defects in the lining, delayed dynamic response of process parameters that cannot timely warn of damage, and incomplete treatment of waste linings causing environmental pollution, which restrict the improvement of the life of the electrolytic cells and their green development. Summary of the invention

[0004] The purpose of the present invention is to provide a method for extending the service life of an electrolytic cell based on a composite material in order to solve the above-mentioned problems.

[0005] The technical solution adopted by the present invention is as follows: a method for extending the service life of an electrolytic cell based on a composite material, the method comprising the following steps:

[0006] S1: Use gradient graphitized cathode carbon blocks, design a microporous structure on the surface to reduce sodium permeability, add silicon carbide reinforcement phase to the bottom layer to improve thermal conductivity; develop a modified phenolic resin and nanocarbon tube composite adhesive to reduce the curing temperature and improve the bonding strength.

[0007] S2: Establish a full-size simulation model of electromagnetic field, temperature field and stress field, optimize the design of trapezoidal composite trough shell, adopt a combined structure of low alloy steel and stainless steel, and set wavy heat dissipation fins on the side wall to reduce the thermal stress peak.

[0008] S3: Deploy distributed infrared heating units, start in stages and control the longitudinal temperature difference; use composite additives to stabilize the electrolyte molecular ratio and reduce the initial crystallization temperature.

[0009] S4: Construct a multi-layer anti-seepage system, including a corundum layer, a silicon nitride combined with a silicon carbide plate, a microporous alumina layer and a graphite foil buffer layer; use nano-microporous thermal insulation materials to improve thermal insulation performance.

[0010] S5: The cathode steel rod is subjected to supersonic flame spraying to prepare a corrosion-resistant coating, and a gradient titanium boride coating is applied on the cathode surface to improve the wettability of the aluminum liquid and reduce the pressure drop at the furnace bottom.

[0011] S6: Integrate multi-source sensors to build a three-dimensional visualization platform and establish a life prediction model based on neural networks; develop a sonar and electromagnetic combined detection system to realize cathode damage warning.

[0012] S7: Establish a multi-parameter linkage control model to adjust the pole distance, alumina concentration, molecular ratio and temperature in real time; use a double-circulation heat transfer oil system to accurately control the temperature difference between the tank and shell.

[0013] S8: Carry out comparative test verification, collect voltage and temperature parameters every hour, apply reliability analysis model to evaluate life indicators, and ensure that the power consumption per ton of aluminum meets the standard.

[0014] S9: Develop a high-temperature purification and regeneration process for cathode carbon blocks to reduce the sodium content, convert waste linings into aluminum-silicon refractory materials, and achieve solid waste reduction and resource recycling.

[0015] In a preferred embodiment, in step S1, a gradient graphitized cathode carbon block is used as the core material, and the surface layer is designed with a microporous structure with a microcrystalline graphite content of 65%, which effectively reduces the sodium permeability by 40%, and introduces 15% silicon carbide reinforcement phase into the bottom layer to increase the thermal conductivity to 65 watts per meter Kelvin. A modified phenolic resin and carbon nanotube composite binder system is developed simultaneously, wherein the carbon nanotube content is controlled at 1.5% to 2.0%, and the curing temperature is reduced from 220°C to 180°C through an in-situ carbonization process, the porosity is compressed to below 8%, and the bonding strength is increased by 40%. The system significantly enhances the cathode's ability to resist sodium expansion, and the expansion rate is controlled within 0.8%.

[0016] In a preferred embodiment, in step S2, a full-scale simulation model of electromagnetic field, temperature field and stress field is constructed based on COMSOL Multiphysics to optimize the trapezoidal composite tank shell structure: the upper part uses 18 mm thick Q345B low alloy steel to improve the overall rigidity, the bottom uses 12 mm 316L stainless steel to enhance corrosion resistance, and the side wall is designed with 50 mm high and 80 mm spacing wavy heat dissipation fins, so that the maximum temperature difference of the tank shell is reduced from 180°C to less than 100°C. The inner lining adopts a stepped cathode carbon block arrangement with a staggered amount of not less than 50 mm, and cooperates with a corundum layer and a silicon nitride combined with a silicon carbide composite anti-seepage structure, and the thermal stress peak is reduced from 85 MPa to 58 MPa.

[0017] In a preferred embodiment, in step S3, a 96-channel infrared thermal imager distributed heating system is deployed, the power density is adjustable at 2 to 8 watts per square centimeter, and a three-stage gradient start-up strategy is implemented: the initial current density is 0.65 amperes per square centimeter, and the rated current is gradually increased in three stages of 24 hours, 48 ​​hours, and 72 hours. Combined with the LiF-AlF3 composite additive, the electrolyte molecular ratio is stabilized at 2.3 to 2.5, the primary crystal temperature is reduced by 15°C, the temperature uniformity of the roasting stage is controlled within ±15°C, and the cathode expansion uniformity reaches 95%.

[0018] In a preferred embodiment, in step S4, a five-layer composite anti-seepage system is constructed, including a 30 mm corundum castable mechanical impact resistance layer, a 50 mm silicon nitride combined with silicon carbide permeation barrier layer, a 20 mm microporous alumina capillary barrier layer, a 5 mm graphite foil stress buffer layer and a 10 mm steel plate support layer. Aluminum silicate fiber-based nano-microporous insulation board is simultaneously applied, 40% silica aerogel and 10% silicon carbide whiskers are added, the thermal conductivity is as low as 0.028 watts per meter Kelvin, the compressive strength exceeds 0.8 MPa, and the heat loss rate is reduced by 18%.

[0019] In a preferred embodiment, in step S5, a supersonic flame spraying process is applied to the cathode steel rod to prepare a 50 micron NiCrAlY transition layer and a 150 micron zirconium oxide-aluminum oxide composite working layer, with a porosity of less than 5%, a contact voltage drop of 18 millivolts, and a service life of 5 years. A three-layer gradient titanium boride coating is applied to the cathode surface, with a content gradually increasing from 60% to 95%, a coating thickness of 200 microns, and after a nitrogen protection heat treatment at 850°C, the furnace bottom precipitation thickness is reduced by 65%, and the cathode wetting angle is reduced to 48 degrees.

[0020] In a preferred embodiment, in step S6, 2000 sensors are integrated to build a three-dimensional visualization platform to collect 18 parameters such as slot voltage and heat flux in real time. A life prediction model is established based on an LSTM neural network, and a 32-dimensional feature vector is input. The prediction error rate is controlled within 5%, and the warning time span is up to 180 days. A distributed acoustic emission and electromagnetic detection system is deployed, with a crack recognition accuracy of over 90%, achieving a 72-hour advance warning of cathode damage.

[0021] In a preferred embodiment, in step S7, a four-element linkage control model is established to dynamically adjust the pole distance to 4.2-4.8 cm, the aluminum oxide concentration to 1.5%-2.5%, the molecular ratio to 2.2-2.4, and the electrolysis temperature to 945-955° C. A dual-circulation heat transfer oil system is used, the main circulation controls the tank shell temperature to 85-95° C., the secondary circulation adjusts the side heat dissipation, the oil flow rate is adjustable to 0.5-2.0 m / s, the tank side thickness is stabilized at 150-200 mm, and the effect coefficient is reduced to less than 0.03 times per tank day.

[0022] In a preferred embodiment, in step S8, 6 530kA electrolytic cells are selected to carry out 18 months of verification test, and the cell voltage, temperature and other data are collected every hour, and the Weibull distribution is applied to perform reliability analysis. The test group is equipped with a gradient composite cathode, a rare earth modified anode and a five-layer anti-seepage system, and the service life is required to exceed 2600 days, the DC power consumption per ton of aluminum is ≤12680 kWh, the current efficiency is ≥94.5%, and the furnace bottom pressure is reduced by 10.5% and the side temperature is reduced by 10.7% compared with the control group.

[0023] In a preferred embodiment, in step S9, a 2300°C vacuum high-temperature purification process is developed to regenerate cathode carbon blocks, the residual sodium content is controlled below 0.8%, and the compressive strength of the regenerated carbon blocks is maintained at 32 MPa. After crushing and grading, 85% of the waste lining is converted into aluminum-silicon refractory materials, and the leaching toxicity meets the GB5085.3 standard. A pneumatic conveying dynamic compensation device is constructed to achieve a pressure fluctuation of ≤±5%, achieving a single tank annual reduction of 15 tons of solid waste emissions and a 40% reduction in unorganized fluoride emissions.

[0024] In summary, due to the adoption of the above technical solution, the beneficial effects of the present invention are:

[0025] 1. In the present invention, the composite structure design of gradient graphitized cathode and silicon carbide reinforcement phase effectively inhibits sodium penetration and thermal stress damage, improves the cathode corrosion resistance by about 40%, and greatly reduces unplanned shutdowns and maintenance due to lining damage. The intelligent roasting startup process cooperates with the dynamic heat balance control system to improve the operating stability of the electrolytic cell by more than 25%, and the current efficiency is increased to 94.5%, directly reducing the DC power consumption per ton of aluminum by about 120 kWh, significantly alleviating the high energy consumption pain point of the electrolytic aluminum industry. The full-cycle material regeneration technology achieves a resource utilization rate of over 85% for waste linings, saves nearly 20% of the annual operation and maintenance costs of a single cell, and forms an economic closed loop for the entire life cycle of the equipment.

[0026] 2. In the present invention, multi-physical field optimization and digital twin technology are integrated to build a technical standard system covering design, manufacturing, operation and maintenance, and promote the iterative upgrade of electrolytic cell equipment towards intelligence. The coordinated application of anti-seepage and heat dissipation composite lining and surface strengthening treatment technology has increased the comprehensive thermal efficiency of the electrolytic cell by 18% and reduced the unorganized emission of fluorides by 40%, providing key technical support for the green transformation of the industry. Through cathode material regeneration and solid waste conversion technology, the environmental pollution problems caused by the overhaul of traditional electrolytic cells can be systematically solved, and resource recycling can be achieved while increasing the service life of equipment, opening up an innovative path for my country's electrolytic aluminum industry to achieve the "dual carbon" goals. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 The figure is a schematic diagram of the process principle of the method of the present invention. DETAILED DESCRIPTION

[0028] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below in conjunction with the accompanying drawings and embodiments. It should be understood that the specific embodiments described herein are only used to explain the present invention and are not used to limit the present invention.

[0029] Example:

[0030] Reference Figure 1 ,

[0031] A method for extending the service life of an electrolytic cell based on a composite material, the method comprising the following steps:

[0032] S1: Use gradient graphitized cathode carbon blocks, design a microporous structure on the surface to reduce sodium permeability, add silicon carbide reinforcement phase to the bottom layer to improve thermal conductivity; develop a modified phenolic resin and nanocarbon tube composite adhesive to reduce the curing temperature and improve the bonding strength.

[0033] S2: Establish a full-size simulation model of electromagnetic field, temperature field and stress field, optimize the design of trapezoidal composite trough shell, adopt a combined structure of low alloy steel and stainless steel, and set wavy heat dissipation fins on the side wall to reduce the thermal stress peak.

[0034] S3: Deploy distributed infrared heating units, start in stages and control the longitudinal temperature difference; use composite additives to stabilize the electrolyte molecular ratio and reduce the initial crystallization temperature.

[0035] S4: Construct a multi-layer anti-seepage system, including a corundum layer, a silicon nitride combined with a silicon carbide plate, a microporous alumina layer and a graphite foil buffer layer; apply nano-microporous thermal insulation materials to improve thermal insulation performance.

[0036] S5: The cathode steel rod is subjected to supersonic flame spraying to prepare a corrosion-resistant coating, and a gradient titanium boride coating is applied on the cathode surface to improve the wettability of the aluminum liquid and reduce the pressure drop at the furnace bottom.

[0037] S6: Integrate multi-source sensors to build a three-dimensional visualization platform and establish a life prediction model based on neural networks; develop a sonar and electromagnetic combined detection system to realize cathode damage warning.

[0038] S7: Establish a multi-parameter linkage control model to adjust the pole distance, alumina concentration, molecular ratio and temperature in real time; use a double-circulation heat transfer oil system to accurately control the temperature difference between the tank and shell.

[0039] S8: Carry out comparative test verification, collect voltage and temperature parameters every hour, apply reliability analysis model to evaluate life indicators, and ensure that the power consumption per ton of aluminum meets the standard.

[0040] S9: Develop a high-temperature purification and regeneration process for cathode carbon blocks to reduce the sodium content, convert waste linings into aluminum-silicon refractory materials, and achieve solid waste reduction and resource recycling.

[0041] In step S1, a gradient graphitized cathode carbon block is used as the core material. The surface layer is designed with a microporous structure with a microcrystalline graphite content of 65%, which effectively reduces the sodium permeability by 40%. The bottom layer introduces 15% silicon carbide reinforcement phase to increase the thermal conductivity to 65 watts per meter Kelvin. A modified phenolic resin and nano-carbon tube composite binder system is developed simultaneously, in which the nano-carbon tube content is controlled at 1.5% to 2.0%, and the curing temperature is reduced from 220°C to 180°C through an in-situ carbonization process, the porosity is compressed to below 8%, and the bonding strength is increased by 40%. The system significantly enhances the cathode's ability to resist sodium expansion, and the expansion rate is controlled within 0.8%.

[0042] In step S2, a full-scale simulation model of electromagnetic field, temperature field and stress field is constructed based on COMSOL Multiphysics to optimize the trapezoidal composite tank shell structure: 18 mm thick Q345B low alloy steel is used on the upper part to improve the overall rigidity, 12 mm 316L stainless steel is used on the bottom to enhance corrosion resistance, and the side wall is designed with 50 mm high and 80 mm spacing wavy heat dissipation fins to reduce the maximum temperature difference of the tank shell from 180°C to less than 100°C. The inner lining adopts a stepped cathode carbon block arrangement with a staggered amount of not less than 50 mm, and is combined with a corundum layer and a silicon nitride combined with a silicon carbide composite anti-seepage structure to reduce the thermal stress peak from 85 MPa to 58 MPa.

[0043] In step S3, a 96-channel infrared thermal imager distributed heating system is deployed, with an adjustable power density of 2 to 8 watts per square centimeter, and a three-stage gradient start-up strategy is implemented: the initial current density is 0.65 amperes per square centimeter, and the current is gradually increased to the rated current in three stages of 24 hours, 48 ​​hours, and 72 hours. Combined with the LiF-AlF3 composite additive, the electrolyte molecular ratio is stabilized at 2.3 to 2.5, the primary crystal temperature is reduced by 15°C, the temperature uniformity of the roasting stage is controlled within ±15°C, and the cathode expansion uniformity reaches 95%.

[0044] In step S4, a five-layer composite anti-seepage system is constructed, including a 30 mm corundum castable mechanical impact resistance layer, a 50 mm silicon nitride combined with silicon carbide permeation barrier layer, a 20 mm microporous alumina capillary barrier layer, a 5 mm graphite foil stress buffer layer and a 10 mm steel plate support layer. Aluminum silicate fiber-based nano-microporous insulation board is simultaneously applied, with 40% silica aerogel and 10% silicon carbide whiskers added, the thermal conductivity is as low as 0.028 watts per meter Kelvin, the compressive strength exceeds 0.8 MPa, and the heat loss rate is reduced by 18%.

[0045] In step S5, the cathode steel rod is subjected to a supersonic flame spraying process to prepare a 50 micron NiCrAlY transition layer and a 150 micron zirconium oxide-aluminum oxide composite working layer, with a porosity of less than 5%, a contact voltage drop of 18 millivolts, and a service life extended to 5 years. A three-layer gradient titanium boride coating is applied to the cathode surface, with the content gradually increasing from 60% to 95%, and a coating thickness of 200 microns. After a nitrogen protection heat treatment at 850°C, the furnace bottom precipitation thickness is reduced by 65%, and the cathode wetting angle is reduced to 48 degrees.

[0046] In step S6, 2,000 sensors are integrated to build a three-dimensional visualization platform to collect 18 parameters such as slot voltage and heat flux in real time. A life prediction model is established based on the LSTM neural network, and a 32-dimensional feature vector is input. The prediction error rate is controlled within 5%, and the warning time span is 180 days. A distributed acoustic emission and electromagnetic detection system is deployed, with a crack recognition accuracy of over 90%, achieving a 72-hour advance warning of cathode damage.

[0047] In step S7, a four-element linkage control model is established to dynamically adjust the pole distance to 4.2-4.8 cm, the aluminum oxide concentration to 1.5%-2.5%, the molecular ratio to 2.2-2.4, and the electrolysis temperature to 945-955° C. A dual-circulation heat transfer oil system is used, the main circulation controls the tank shell temperature to 85-95° C., the secondary circulation adjusts the side heat dissipation, the oil flow rate is adjustable to 0.5-2.0 meters per second, the tank side thickness is stabilized at 150-200 mm, and the effect coefficient is reduced to less than 0.03 times per tank day.

[0048] In step S8, 6 530kA electrolytic cells were selected to carry out 18 months of verification test, and the cell voltage, temperature and other data were collected every hour, and the Weibull distribution was applied for reliability analysis. The test group was equipped with a gradient composite cathode, a rare earth modified anode and a five-layer anti-seepage system, and the service life was required to exceed 2600 days, the DC power consumption per ton of aluminum was ≤12680 kWh, the current efficiency was ≥94.5%, and the furnace bottom pressure was reduced by 10.5% and the side temperature was reduced by 10.7% compared with the control group.

[0049] In step S9, a 2300℃ vacuum high-temperature purification process is developed to regenerate cathode carbon blocks, the residual sodium content is controlled below 0.8%, and the compressive strength of the regenerated carbon blocks is maintained at 32 MPa. After crushing and grading, 85% of the waste lining is converted into aluminum-silicon refractory materials, and the leaching toxicity meets the GB5085.3 standard. A pneumatic conveying dynamic compensation device is built to achieve a pressure fluctuation of ≤±5%, achieving a single tank annual reduction of 15 tons of solid waste emissions and a 40% reduction in unorganized fluoride emissions.

[0050] From the above, it can be known that: in the present invention, the composite structure design of gradient graphitized cathode and silicon carbide reinforcement phase effectively inhibits sodium penetration and thermal stress damage, improves the cathode corrosion resistance by about 40%, and greatly reduces unplanned shutdowns and maintenance due to lining damage. The intelligent roasting startup process cooperates with the dynamic heat balance control system to improve the operating stability of the electrolytic cell by more than 25%, and the current efficiency is increased to 94.5%, directly reducing the DC power consumption per ton of aluminum by about 120 kWh, significantly alleviating the high energy consumption pain point of the electrolytic aluminum industry. The full-cycle material regeneration technology achieves a resource utilization rate of over 85% for waste linings, saves nearly 20% of the annual operation and maintenance costs of a single cell, and forms an economic closed loop for the entire life cycle of the equipment.

[0051] In this invention, multi-physics field optimization and digital twin technology are integrated to build a technical standard system covering design, manufacturing, operation and maintenance, and promote the iterative upgrade of electrolytic cell equipment towards intelligence. The coordinated application of anti-seepage and heat dissipation composite lining and surface strengthening treatment technology has increased the comprehensive thermal efficiency of the electrolytic cell by 18% and reduced the unorganized emission of fluorides by 40%, providing key technical support for the green transformation of the industry. Through cathode material regeneration and solid waste conversion technology, the environmental pollution problems caused by the overhaul of traditional electrolytic cells are systematically solved, and resource recycling is realized while increasing the service life of equipment, opening up an innovative path for my country's electrolytic aluminum industry to achieve the "dual carbon" goals.

[0052] It should be noted that, in this article, relational terms such as first and second, etc. are only used to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations. Moreover, the term "comprise" or any other variant thereof is intended to cover non-exclusive inclusion, so that a process, method, article or device including a series of elements includes not only those elements, but also other elements not explicitly listed, or also includes elements inherent to such process, method, article or device. In the absence of further restrictions, the elements defined by the sentence "comprise a ..." do not exclude the existence of other identical elements in the process, method, article or device including the elements.

[0053] The above embodiments are only used to illustrate the technical solutions of the present invention, rather than to limit the same. Although the present invention has been described in detail with reference to the aforementioned embodiments, those skilled in the art should understand that the technical solutions described in the aforementioned embodiments may still be modified, or some of the technical features may be replaced by equivalents. However, these modifications or replacements do not deviate the essence of the corresponding technical solutions from the spirit and scope of the technical solutions of the embodiments of the present invention.

Claims

1. A method for extending the service life of an electrolytic cell based on a composite material, characterized in that: The method comprises the following steps: S1: Use gradient graphitized cathode carbon blocks, design microporous structures on the surface to reduce sodium permeability, add silicon carbide reinforcement phase to the bottom layer to improve thermal conductivity; develop modified phenolic resin and nano-carbon tube composite adhesives to reduce curing temperature and improve bonding strength; S2: Establish a full-scale simulation model of electromagnetic field, temperature field and stress field, optimize the design of trapezoidal composite trough shell, adopt a combined structure of low alloy steel and stainless steel, and set wavy heat dissipation fins on the side wall to reduce the peak value of thermal stress; S3: deploy distributed infrared heating units, start gradient in stages and control the longitudinal temperature difference; use composite additives to stabilize the electrolyte molecular ratio and reduce the initial crystallization temperature; S4: construct a multi-layer anti-seepage system, including a corundum layer, a silicon nitride combined with a silicon carbide plate, a microporous alumina layer and a graphite foil buffer layer; apply nano-microporous thermal insulation materials to improve thermal insulation performance; S5: preparing a corrosion-resistant coating by supersonic flame spraying on the cathode steel rod, and coating a gradient titanium boride coating on the cathode surface to improve the wettability of the aluminum liquid and reduce the pressure drop at the furnace bottom; S6: Integrate multi-source sensors to build a 3D visualization platform and establish a life prediction model based on neural networks; develop a sonar and electromagnetic combined detection system to achieve cathode damage warning; S7: Establish a multi-parameter linkage control model to adjust the pole distance, alumina concentration, molecular ratio and temperature in real time; use a double-circulation heat transfer oil system to accurately control the temperature difference between the tank and shell; S8: Carry out comparative test verification, collect voltage and temperature parameters every hour, apply reliability analysis model to evaluate life indicators, and ensure that the power consumption per ton of aluminum meets the standard; S9: Develop a high-temperature purification and regeneration process for cathode carbon blocks to reduce the sodium content, convert waste linings into aluminum-silicon refractory materials, and achieve solid waste reduction and resource recycling.

2. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In step S1, a gradient graphitized cathode carbon block is used as the core material, the surface layer is designed with a microporous structure with a microcrystalline graphite content of 65%, which effectively reduces the sodium permeability by 40%, and the bottom layer is introduced with a 15% silicon carbide reinforcement phase to increase the thermal conductivity to 65 watts per meter Kelvin; We simultaneously developed a modified phenolic resin and carbon nanotube composite binder system, in which the carbon nanotube content was controlled at 1.5% to 2.0%. Through an in-situ carbonization process, the curing temperature was reduced from 220°C to 180°C, the porosity was compressed to below 8%, and the bonding strength was increased by 40%. This system significantly enhanced the cathode's ability to resist sodium expansion, and the expansion rate was controlled within 0.8%.

3. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In the step S2, a full-size simulation model of the electromagnetic field, temperature field and stress field is constructed based on COMSOL Multiphysics to optimize the trapezoidal composite tank shell structure: the upper part uses 18 mm thick Q345B low-alloy steel to improve the overall rigidity, the bottom uses 12 mm 316L stainless steel to enhance the corrosion resistance, and the side wall is designed with 50 mm high and 80 mm spacing wavy heat dissipation fins to reduce the maximum temperature difference of the tank shell from 180°C to within 100°C; the inner lining adopts a stepped cathode carbon block arrangement with a staggered gap of not less than 50 mm.

4. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In step S3, a 96-channel infrared thermal imager distributed heating system is deployed, the power density is adjustable between 2 and 8 watts per square centimeter, and a three-stage gradient startup strategy is implemented: the initial current density is 0.65 amperes per square centimeter, and the current is gradually increased to the rated current in three stages of 24 hours, 48 ​​hours, and 72 hours.

5. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In step S4, a five-layer composite anti-seepage system is constructed, including a 30 mm corundum castable mechanical impact resistance layer, a 50 mm silicon nitride combined with silicon carbide barrier layer, a 20 mm microporous alumina capillary barrier layer, a 5 mm graphite foil stress buffer layer and a 10 mm steel plate support layer.

6. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In the step S5, a supersonic flame spraying process is performed on the cathode steel rod to prepare a 50 micron NiCrAlY transition layer and a 150 micron zirconium oxide-aluminum oxide composite working layer, the porosity is less than 5%, the contact voltage drop is reduced by 18 millivolts, and the service life is extended to 5 years; The cathode surface adopts three layers of gradient titanium boride coating, the content of which gradually increases from 60% to 95%, and the coating thickness is 200 microns. After heat treatment under nitrogen protection at 850°C, the thickness of the furnace bottom precipitation is reduced by 65%, and the cathode wetting angle is reduced to 48 degrees.

7. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In step S6, 2000 sensors are integrated to build a three-dimensional visualization platform to collect 18 parameters such as slot voltage and heat flux density in real time; a life prediction model is established based on an LSTM neural network, and a 32-dimensional feature vector is input. The prediction error rate is controlled within 5%, and the warning time span is up to 180 days; a distributed acoustic emission and electromagnetic detection system is deployed, and the crack recognition accuracy rate exceeds 90%, achieving a 72-hour advance warning of cathode damage.

8. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In the step S7, a four-element linkage control model is established to dynamically adjust the pole distance to 4.2-4.8 cm, the aluminum oxide concentration to 1.5%-2.5%, the molecular ratio to 2.2-2.4, and the electrolysis temperature to 945-955° C.; a double-circulation heat transfer oil system is adopted, the main circulation controls the tank shell temperature to 85-95° C., the secondary circulation adjusts the side heat dissipation, the oil flow rate is adjustable to 0.5-2.0 meters per second, the tank wall thickness is stabilized at 150-200 mm, and the effect coefficient is reduced to less than 0.03 times per tank day.

9. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In step S8, six 530kA electrolytic cells are selected to carry out an 18-month verification test, and the cell voltage, temperature and other data are collected every hour, and the Weibull distribution is applied to perform reliability analysis; the test group is equipped with a gradient composite cathode, a rare earth modified anode and a five-layer anti-seepage system, and the service life is required to exceed 2600 days, the DC power consumption per ton of aluminum is ≤12680 kWh, the current efficiency is ≥94.5%, and the furnace bottom pressure is reduced by 10.5% and the side temperature is reduced by 10.7% compared with the control group.

10. A method for extending the service life of an electrolytic cell based on a composite material as claimed in claim 1, characterized in that: In the step S9, a 2300°C vacuum high-temperature purification process is developed to regenerate cathode carbon blocks, the sodium residue is controlled below 0.8%, and the compressive strength of the regenerated carbon blocks is maintained at 32 MPa; after crushing and grading, 85% of the waste lining is converted into aluminum-silicon refractory materials, and the leaching toxicity meets the GB5085.3 standard; a pneumatic conveying dynamic compensation device is constructed to achieve a pressure fluctuation of ≤±5%, thereby reducing solid waste emissions by 15 tons per tank per year and reducing unorganized fluoride emissions by 40%.

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