A current-sharing composite electrolytic aluminum anode structure

Abstract

The utility model belongs to the energy -conserving and carbon -reducing electrolytic aluminium anode technical field, especially relates to a current -sharing composite electrolytic aluminium anode structure, and anode structure includes aluminium alloy guide rod, is located aluminium alloy guide rod bottom and its fixed connection's section is the composite transition structure of convex, and the composite transition structure is fixedly connected with carbon top through the graphene / copper composite expansion connecting column of its bottom, the utility model discloses the addition of graphene / copper composite board has reduced the interface resistance between expansion connecting structure and carbon, and when anode is installed on electrolytic cell, anode overall temperature rises, graphene / copper composite expansion connecting structure is heated, produces the thermal expansion outward, and the contact resistance with carbon is also smaller.

Description

Technical Field

[0001] This utility model belongs to the field of energy-saving and carbon-reducing electrolytic aluminum anode technology, and particularly relates to a current-equalizing composite electrolytic aluminum anode structure. Background Technology

[0002] Modern aluminum industry employs the Hall-Eruth molten salt electrolysis method with prebaked anode electrolytic cells. Aluminum electrolysis is extremely energy-intensive; typically, 1 ton of primary aluminum requires 13,000-14,000 kWh of electricity. Currently, most aluminum electrolysis anode structures still use a combination of aluminum guide rods, aluminum / steel explosive weld blocks, steel claws, pig iron, and carbon components. For the entire aluminum electrolysis cell equipment, this anode structure accounts for approximately 10% of the total system's energy consumption, making anode structure improvement imperative. Utility Model Content

[0003] The purpose of this invention is to provide a uniform flow composite electrolytic aluminum anode structure and its preparation method.

[0004] To achieve the above objectives, the technical solution adopted by this utility model is as follows: A current-equalizing composite electrolytic aluminum anode structure includes an aluminum alloy guide rod and a convex-shaped composite transition structure fixedly connected to the bottom of the aluminum alloy guide rod. The composite transition structure is fixedly connected to the upper carbon component through a graphene / copper composite expansion connecting column at its bottom.

[0005] Furthermore, an aluminum alloy flow equalization plate is also provided between the aluminum alloy guide rod and the composite transition structure.

[0006] Furthermore, the upper part of the carbon fiber is provided with multiple blind holes evenly arranged along its length. The graphene / copper composite expansion connecting post is inserted into the blind hole and fixed by bolts. The length of the graphene / copper composite expansion connecting post is 80-100mm, and the number is 6-12. This arrangement makes the stress and conductivity more uniform. Compared with the original phosphorus pig iron with a depth of about 150mm, this design reduces the residual electrode thickness while ensuring strength, improves the carbon utilization rate by more than 10%, and reduces the cost per ton of aluminum and carbon emissions.

[0007] Furthermore, the composite transition structure includes a pure aluminum plate on the upper surface, steel connected to the pure aluminum plate, a graphene / copper composite plate located below the steel, and a graphene / copper composite expansion connecting column located at the bottom of the graphene / copper composite plate, wherein the graphene / copper composite expansion connecting column is uniformly distributed along the length direction of the graphene / copper composite plate.

[0008] Furthermore, the steel is provided with multiple evenly distributed lifting and heat dissipation holes, which can be used for lifting and transporting the anode structure, and can also isolate the high temperature environment of the electrolytic cell from the aluminum / steel interface. The temperature inside the electrolytic cell is about 900℃, and the reserved heat insulation holes effectively ensure that the temperature of the aluminum / steel interface does not exceed 550℃.

[0009] A method for preparing a current-equalizing composite electrolytic aluminum anode structure includes the following steps: S1. Using Ansys finite element simulation analysis to assist in design, and combining the electrical conductivity, thermal conductivity, and specific heat capacity parameters of aluminum alloy, steel, and graphene / copper composite materials, the dimensions of each component are simulated and designed within the range that meets the requirements of uniform current distribution and reasonable heat distribution in the anode structure. S2. Preparation of composite transition structure: Steel is manufactured into long strips with convex cross-section by casting, forging and CNC machining, and then composited with pure aluminum plate on top and graphene / copper composite plate on bottom by explosive welding, with heat insulation holes reserved in the steel. S3. The bottom of the aluminum alloy guide rod is welded to the pure aluminum plate, the bottom of the aluminum alloy flow equalization plate is welded to the pure aluminum plate, and the side wall of the aluminum alloy guide rod is welded to the aluminum alloy flow equalization plate by gas metal arc welding with bevel welding. The temperature of the composite interface is controlled not to exceed 400℃, forming a structure in which the aluminum alloy guide rod, the aluminum alloy flow equalization plate, and the composite transition structure are integrated. S4. Fix the graphene / copper composite expansion joint to the composite transition structure by friction stir welding, and then insert the graphene / copper composite expansion joint into the blind hole reserved in the upper part of the carbon fiber and fix it with bolts.

[0010] The advantages of this utility model are: 1. The addition of the graphene / copper composite plate in this utility model reduces the interfacial resistance between the expansion connection structure and carbon. Moreover, when the anode is installed on the electrolytic cell, the overall temperature of the anode rises, the graphene / copper composite expansion connection structure is heated, and outward thermal expansion is generated, resulting in a smaller contact resistance with carbon. 2. The graphene / copper composite expansion connecting column of this utility model has a depth of 80-100mm and is evenly distributed in 6-12 groups, resulting in more uniform stress and conductivity. Compared with the original phosphorus pig iron with a depth of about 150mm, this design reduces the residual electrode thickness while ensuring strength, increases carbon utilization by more than 10%, and reduces the cost per ton of aluminum and carbon emissions. 3. This utility model uses bolt expansion connecting columns to connect the composite transition structure with carbon fiber, which is simple in structure and very convenient to assemble and disassemble. Compared with the original phosphorus pig iron casting, it does not require complex equipment such as heating, fixing, breaking, and crushing. Attached Figure Description

[0011] Figure 1This is a schematic diagram of the structure of an electrolytic aluminum anode prepared using the method of this invention.

[0012] Figure 2 This is a schematic diagram of a composite transition structure.

[0013] Figure 3 It is a diagram of the expansion connection structure between the composite transition structure and carbon.

[0014] In the diagram: 1. Aluminum alloy guide rod; 2. Aluminum alloy flow equalization plate; 3. Composite transition structure; 4. Lifting heat dissipation hole; 5. Carbon; 3-1. Graphene / copper composite expansion connection column; 3-2. Graphene / copper composite plate; 3-3. Structural steel; 3-4. Pure aluminum plate. Detailed Implementation

[0015] like Figure 1-3 As shown, a current-equalizing composite electrolytic aluminum anode structure includes an aluminum alloy guide rod 1 and a convex-shaped composite transition structure 3 fixedly connected to the bottom of the aluminum alloy guide rod 1. The composite transition structure is fixedly connected to the upper part of the carbon fiber 5 through a graphene / copper composite expansion connecting column 3-1 at its bottom. An aluminum alloy current-equalizing plate 2 is also provided between the aluminum alloy guide rod 1 and the composite transition structure 3. The upper part of the carbon fiber has multiple blind holes evenly arranged along its length. The graphene / copper composite expansion connecting column 3-1 is inserted into the blind holes and fixed by bolts. The length of the graphene / copper composite expansion connecting column is 80-100mm, and the number is 6-12. This arrangement makes the stress and conductivity more uniform. Compared with the original phosphorus pig iron with a depth of about 150mm, this design reduces the residual anode thickness while ensuring strength, increases the carbon utilization rate by more than 10%, and reduces the cost per ton of aluminum and carbon emissions. The composite transition structure includes... The structure consists of a pure aluminum plate 3-4 on the upper surface, a steel material 3-3 connected to the pure aluminum plate, a graphene / copper composite plate 3-2 located at the lower part of the steel material, and a graphene / copper composite expansion connecting column 3-1 located at the bottom of the graphene / copper composite plate. The graphene / copper composite expansion connecting column is evenly distributed along the length of the graphene / copper composite plate. The steel material is provided with multiple evenly distributed hoisting and heat dissipation holes 4, which can be used for hoisting and transporting the anode structure, and can also isolate the high temperature environment of the electrolytic cell from the influence of the aluminum / steel interface. The temperature inside the electrolytic cell is about 900℃, and the reserved heat insulation holes effectively ensure that the temperature of the aluminum / steel interface does not exceed 550℃.

[0016] A method for preparing a current-equalizing composite electrolytic aluminum anode structure includes the following steps: S1. Using Ansys finite element simulation analysis to assist in design, and combining the electrical conductivity, thermal conductivity, and specific heat capacity parameters of aluminum alloy, steel, and graphene / copper composite materials, the dimensions of each component are simulated and designed within the range that meets the requirements of uniform current distribution and reasonable heat distribution in the anode structure. S2. Preparation of composite transition structure: Steel is manufactured into long strips with convex cross-section by casting, forging and CNC machining, and then composited with pure aluminum plate on top and graphene / copper composite plate on bottom by explosive welding, with heat insulation holes reserved in the steel. S3. The bottom of the aluminum alloy guide rod is welded to the pure aluminum plate, the bottom of the aluminum alloy flow equalization plate is welded to the pure aluminum plate, and the side wall of the aluminum alloy guide rod is welded to the aluminum alloy flow equalization plate by gas metal arc welding with bevel welding. The temperature of the composite interface is controlled not to exceed 400℃, forming a structure in which the aluminum alloy guide rod, the aluminum alloy flow equalization plate, and the composite transition structure are integrated. S4. Fix the graphene / copper composite expansion joint to the composite transition structure by friction stir welding, and then insert the graphene / copper composite expansion joint into the blind hole reserved in the upper part of the carbon fiber and fix it with bolts.

[0017] Test case 1. Using the industrial analysis section of Ansys finite element simulation software, simulation experiments were conducted with currents of 5kA, 7.5kA, and 10kA. Considering the pure aluminum interface temperature is ≤550℃, current bottlenecks were avoided, and appropriate design schemes were selected based on the simulated temperature changes. Results show: 2. To avoid stress concentration during welding, a symmetrical welding setup should be adopted, and symmetrical welding should also be used to avoid excessive stress concentration.

[0018] 3. Considering the uncertainties in the high current and high temperature environment of the electrolytic cell, the processing parameters need to be adjusted and formulated with reference to the simulation results.

[0019] Interface strength: Tensile strength of aluminum-steel interface ≥100MPa, shear strength ≥60MPa; Tensile strength of graphene / copper composite material interface with steel ≥200MPa, shear strength ≥100MPa.

[0020] The depth of the graphene / copper composite expansion joint is 80-100mm.

[0021] Flatness: Aluminum alloy guide rod ≤1mm / m, composite transition structure top and bottom surfaces ≤2mm / m 2 .

[0022] Size: ±1mm Surface roughness at the contact location ≤ Ra1.6 4. Before installation in the tank, the conductivity of the anode can be calculated by voltage drop testing. The current intensity is 300A, and the voltage drop is then converted to 5kA, 7.5kA, and 10kA.

[0023] Before being placed in the tank, the resistance between the aluminum guide rod and carbon in a traditional electrolytic aluminum anode structure was measured to be 0.1170~0.1195mΩ, while the resistance of an energy-saving, carbon-reducing, and current-equalizing composite electrolytic aluminum anode was 0.0450~0.0468mΩ, an average reduction of approximately 60%. After the tank was energized and stabilized, the connection points expanded due to high temperature, resulting in a tighter fit. The resistance of the traditional electrolytic aluminum anode structure was 0.0190~0.024mΩ, while the resistance of the energy-saving, carbon-reducing, and current-equalizing composite electrolytic aluminum anode was 0.0110~0.0150mΩ, an average reduction of approximately 40%.

Claims

1. A current-equalizing composite electrolytic aluminum anode structure, characterized in that: The system includes an aluminum alloy guide rod and a convex-shaped composite transition structure fixedly connected to the bottom of the aluminum alloy guide rod. The composite transition structure is fixedly connected to the upper part of the carbon component through a graphene / copper composite expansion connecting column at its bottom. The composite transition structure includes a pure aluminum plate on the upper surface, steel connected to the pure aluminum plate, a graphene / copper composite plate at the lower part of the steel, and a graphene / copper composite expansion connecting column at the bottom of the graphene / copper composite plate. The graphene / copper composite expansion connecting column is uniformly distributed along the length of the graphene / copper composite plate.

2. The current-equalizing composite electrolytic aluminum anode structure as described in claim 1, characterized in that: An aluminum alloy flow equalization plate is also provided between the aluminum alloy guide rod and the composite transition structure.

3. The current-equalizing composite electrolytic aluminum anode structure as described in claim 1, characterized in that: The upper part of the carbon fiber is provided with multiple blind holes evenly arranged along the length direction. The graphene / copper composite expansion connecting post is inserted into the blind hole and fixed by bolts. The length of the graphene / copper composite expansion connecting post is 80-100mm and the number is 6-12.

4. The current-equalizing composite electrolytic aluminum anode structure as described in claim 1, characterized in that: The steel has multiple evenly distributed hoisting and heat dissipation holes.

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