Energy-saving anode conductive device for aluminum electrolysis and manufacturing method thereof

Abstract

This invention discloses an energy-saving anode conductive device for aluminum electrolysis and its manufacturing method. The anode conductive device includes an anode guide rod, an intermediate aluminum block, a carbon block, and an anode steel claw. The anode steel claw has a shaft hole. The intermediate aluminum block and the anode steel claw are connected via the shaft hole using an interference fit. The lower surface of the anode guide rod is welded to the top of the intermediate aluminum block. Finally, metal powder is sprayed onto the aluminum-steel connection. This invention uses an interference fit connection method, avoiding the brittle metallic phase generated at the joint during welding of dissimilar aluminum and steel materials in traditional aluminum electrolysis anode conductive devices. It also reduces the number of welds. Simultaneously, the spraying technology improves the bonding strength and conductive area at the aluminum-steel connection. It features low pressure drop, simple structure, high connection strength, and ease of manufacturing and maintenance, resulting in significant economic and social benefits.

Description

Technical Field

[0001] The present invention relates to the field of nonferrous metal metallurgy, and in particular to an energy-saving anode conductive device for aluminum electrolysis and a manufacturing method thereof. Background Art

[0002] In the electrolytic aluminum industry, the anode conductive assembly consists of an anode aluminum guide rod and an anode steel claw. In industrial applications, the anode assembly operates in a high-temperature, highly corrosive environment. It must conduct high currents while also bearing the weight of the steel claw and carbon block. Therefore, the performance requirements for the aluminum-steel joint are extremely high.

[0003] The existing technology is to weld the aluminum-steel explosive welding block to the aluminum guide rod and the anode steel claw along the four sides of the contact area respectively, which can effectively avoid the formation of brittle intermetallic compounds during aluminum-steel welding. However, the expansion coefficients of aluminum and steel are quite different. Under the action of high temperature and high current, shear force is generated at the joint of the composite welding block, causing cracking of the welding surface, thereby reducing the conductive area and increasing the resistance, further aggravating the fracture tendency at the joint.

[0004] Patent CN109338412A discloses an anode steel claw connected by welding and support bolts and an assembly method thereof. This patent improves the connection strength between the aluminum guide rod and the steel claw through bolt connection, but it has the problem of complex processing technology and the processing of through holes on the guide rod easily leads to uneven distribution of anode current. At the same time, the bolts are more susceptible to current and high-temperature corrosion, increasing the maintenance cost of the equipment; Patent CN109518229A discloses a method of connecting the anode guide rod and the steel claw by friction welding. Although its service life is greatly improved, the aluminum-steel connection joint obtained by friction welding will cause the anode guide rod to shorten due to friction during the maintenance or replacement process, which is not conducive to the recycling and reuse of the anode guide rod. At the same time, the friction welding equipment is expensive, the production cost of the enterprise is too high, and it is difficult to promote in the industry.

[0005] The anode conductive devices for aluminum electrolysis disclosed in patents CN216304001U, CN214937862U and CN216141636U are composed of an aluminum guide rod, an anode steel claw and a steel-aluminum connector. The connection between the anode guide rod and the anode steel claw is achieved by welding the lower side of the guide rod to the aluminum rod on the upper part of the steel-aluminum connector, and welding the upper surface of the steel claw crossbeam to the lower end face of the steel rod of the steel-aluminum connector. From the disclosed content, it can be seen that this technical solution has the problems of complex structure and high production cost. The conductive area is limited by welding the aluminum rod to the side of the guide rod. In order to increase the conductive area of ​​the device, the number of steel-aluminum connectors must be increased. The steel-aluminum connectors use steel sleeves to increase the strength, which makes the overall weight and size of the device too large, further increasing the difficulty of maintenance and replacement of the device, which is not conducive to enterprises reducing production costs. Summary of the Invention

[0006] In response to the above problems, in order to reduce the production, maintenance and use costs of the anode conductive device, the present invention provides an energy-saving anode conductive device for aluminum electrolysis and a manufacturing method thereof, which adopts a method combining interference fit and aluminum-aluminum welding of the same material to achieve the connection between the anode guide rod and the anode steel claw, thereby providing a low-cost, high connection strength and simple structure connection method.

[0007] The specific technical solutions are as follows:

[0008] A first aspect of the present invention is to provide a method for manufacturing an energy-saving anode conductive device for aluminum electrolysis, which has the following characteristics and comprises the following steps:

[0009] 1) Obtain the outer diameter of the anode guide rod, and subtract the interference from the outer diameter of the anode guide rod to obtain the inner diameter of the shaft hole;

[0010] 2) A design calculation model for the aluminum-steel cylindrical interference joint was established based on the relevant performance parameters of the anode guide rod and anode steel claw, and the relationship between the interference and contact stress was obtained. Based on the actual working conditions of the aluminum-steel interference joint, a finite element model of the aluminum-steel interference joint was established using finite element analysis software, and the model boundary conditions were set according to the actual assembly working conditions.

[0011] 3) Under the condition of the same interference, the first average contact stress value of the calculation model and the second average contact stress value of the finite element model are obtained respectively, and the deviation value between the first stress value and the second stress value is calculated to verify the calculation accuracy of the simulation model;

[0012] 4) According to the actual working conditions, the minimum joint length l is calculated based on the weight G of the anode steel claw and carbon block, the friction coefficient μ of the anode guide rod and the anode steel claw, and the inner diameter d0 of the shaft hole. min ;

[0013] 5) According to the size of the middle axis hole in 1), the axis hole is opened on the anode steel claw, and then according to the minimum connection length l min ×(3~500) Process the intermediate aluminum block, assemble the intermediate aluminum block on the anode steel claw through the shaft hole in an interference fit manner, weld the anode guide rod to the intermediate aluminum block, and then assemble the carbon block on the anode steel claw;

[0014] 6) Spray metal powder at the junction of the anode guide rod, the middle aluminum block and the anode steel claw to improve the bonding strength of the aluminum-steel connection and increase the conductive area.

[0015] The above manufacturing method also has the following feature: if the ratio of the deviation value to the first average contact stress value in step 3) is less than 5%, the simulation model and the second average contact stress value are credible.

[0016] The above manufacturing method also has the following characteristics: the minimum connection length in step 4) must meet the following requirements: after the anode guide rod is fixed under the interference fit, the anode steel claw and the anode guide rod do not slide relative to each other under the combined action of the anode steel claw and the carbon block's own gravity.

[0017] The above manufacturing method also has the feature that in step 5), the shaft hole can be directly opened on the crossbeam of the existing model anode steel claw.

[0018] The above-mentioned manufacturing method is further characterized in that in step 5), an axial hole can be provided on the boss of the anode steel claw with boss formed by integral casting.

[0019] The above manufacturing method also has the following characteristics: in step 5), a boss can be first assembled on the crossbeam of the existing anode steel claw, and then an axis hole can be opened on the boss.

[0020] The above manufacturing method also has the following feature: in step 5), the lower end surface of the anode guide rod can be polished first and then connected to the middle aluminum block by self-propagating welding to achieve efficient and rapid full-melting welding.

[0021] The above manufacturing method also has the following feature: the metal powder in step 6) is selected from but not limited to one or more of aluminum powder, copper powder or zinc powder.

[0022] The second aspect of the present invention is to provide an energy-saving anode conductive device for aluminum electrolysis, which has the following characteristics and is manufactured according to the above-mentioned manufacturing method.

[0023] The beneficial effects of the above scheme are:

[0024] 1) The present invention combines a mathematical calculation model with a finite element simulation model to obtain the relationship between the interference and the average contact stress, thereby designing the shaft hole size and the joint length, thereby avoiding a large number of assembly and testing experiments and effectively reducing design costs;

[0025] 2) Compared with conventional anode conductive devices for aluminum electrolysis, the aluminum-steel interference fit connection method of the present invention avoids the brittle metal phase generated at the joint when the aluminum-steel dissimilar materials are welded, thereby improving the strength of the joint;

[0026] 3) Compared with the current three-contact surface welding manufacturing process, the conductive device provided by the present invention has the advantages of simple structure, simplified process, and greatly reduced manufacturing and maintenance costs;

[0027] 4) Compared with traditional connection methods such as explosive welding blocks and steel sleeves, the present invention reduces the number of welds and simplifies the original three joints of steel-steel, steel-aluminum, and aluminum-aluminum to two joints of steel-aluminum mechanical connection and aluminum-aluminum welding of the same material, effectively reducing the pressure drop at the connection between the anode guide rod and the anode steel claw, thereby achieving energy conservation and emission reduction;

[0028] 5) The present invention can process bosses on the steel claw beam, which greatly increases the contact area of ​​the interference fit through the bosses, thereby ensuring the conductivity and mechanical properties of the entire anode conductive device;

[0029] 6) The present invention provides an intermediate aluminum block for interference fit connection, which greatly improves the industrial applicability of this conductive structure and saves manpower and material resources. After all, integrally heating steel claws or integrally cooling guide rods is time-consuming and labor-intensive in industrial production, consuming a large amount of energy. Cooling the intermediate aluminum block is a very simple task, thus easily achieving continuous production and reducing overall investment.

[0030] 7) The lower end surface of the anode guide rod of the present invention is polished and connected to the middle aluminum block by self-propagating welding, achieving efficient and rapid full-melting welding and ensuring 100% conductivity of the aluminum-aluminum part;

[0031] 8) In the present invention, the side wall of the middle aluminum block contacts the inner wall of the shaft hole, and a coating is formed at the aluminum-steel junction by spraying to further improve the bonding strength, increase the conductive area and reduce the voltage drop;

[0032] 9) The present invention discretizes complex production processes that are difficult to industrialize and have inherently insufficient conductive properties, and each step can be automated. The entire production process saves the company's production costs and has the potential for large-scale industrial production and application. BRIEF DESCRIPTION OF THE DRAWINGS

[0033] Figure 1 A schematic structural diagram of a conductive device provided in an embodiment of the present invention;

[0034] Figure 2 This is a schematic diagram of simulation calculation results provided in Example 1 of the present invention;

[0035] Figure 3 This is a metallographic diagram of the joint surface provided in Example 1 of the present invention.

[0036] In the attached figure: 1. anode guide rod; 2. spray coating; 3. aluminum-aluminum self-propagating welding surface; 4. anode steel claw transition block; 5. intermediate aluminum block; 6. aluminum-steel interference fit surface; 7. anode steel claw. DETAILED DESCRIPTION

[0037] The following will clearly and completely describe the technical solutions in the embodiments of the present invention in conjunction with the accompanying drawings. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making any creative efforts shall fall within the scope of protection of the present invention.

[0038] It should be noted that, in the absence of conflict, the embodiments of the present invention and the features in the embodiments may be combined with each other.

[0039] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but they are not intended to limit the present invention.

[0040] Example 1

[0041] An energy-saving anode conductive device for aluminum electrolysis, and a manufacturing method thereof are as follows:

[0042] 1) Based on the actual working conditions of the existing anode conductive device, a proportional reduction model was established, and the outer diameter of the anode guide rod was obtained to be 29.96 mm, the inner diameter of the shaft hole was obtained to be 29.89 mm (the inner diameter of the shaft hole was obtained by subtracting the interference fit from the outer diameter of the anode guide rod), and the outer diameter of the shaft hole was obtained to be 43.00 mm;

[0043] 2) The design calculation model of the aluminum-steel cylindrical interference connection is established based on the relevant performance parameters of the anode guide rod 1 and the anode steel claw 7, and the relationship between the interference and contact stress is obtained. 4 ×δ / 7.5145MPa; Based on the actual working conditions of aluminum-steel interference joint, the finite element model of aluminum-steel interference joint was established using finite element analysis software, and the model boundary conditions were set according to the actual assembly working conditions;

[0044] 3) Under the condition of optimal interference δ = 0.07 mm (the outer diameter of the intermediate aluminum block is the same as the outer diameter of the anode guide rod. When the outer diameter of the intermediate aluminum block shrinks to the maximum after freezing, the difference between its size and the inner diameter of the shaft hole is the optimal interference, that is, the difference between the maximum shrinkage of the intermediate aluminum block and the optimal variation margin of the assembly size is the optimal interference), the first average contact stress value of the calculation model is 93.154 MPa and the second average contact stress value of the finite element model is 92.288 MPa. The calculated deviation between the first stress value and the second stress value is 0.866 MPa, and the ratio of the difference to the first average contact stress is 0.938%, indicating that the calculation of the simulation model is credible;

[0045] 4) According to the actual working conditions, the friction coefficient μ of the anode steel claw 7 and the carbon block weight G, the anode guide rod 1 and the anode steel claw 7, and the inner diameter d0 of the shaft hole, the formula l is used. min =G / (μPπd0) to calculate the minimum binding length l min ;

[0046] 5) According to the size of the middle hole in 1), a hole is opened on the anode steel claw 7 (the inner diameter of the hole is 29.89mm and the outer diameter of the hole is 43.00mm), and then according to the minimum connection length l min×(3~500) Process the intermediate aluminum block, assemble it on the anode steel claw through the shaft hole in an interference fit manner, grind the lower end surface of the anode guide rod and then connect it to the intermediate aluminum block by self-propagating welding to achieve efficient and rapid full-melting welding, and then assemble the carbon block on the anode steel claw;

[0047] 6) Spray metal powder (one or more of aluminum powder, copper powder or zinc powder) at the junction of the anode guide rod, the middle aluminum block and the anode steel claw to improve the bonding strength of the aluminum-steel connection and increase the conductive area;

[0048] Among them, the relevant performance parameters of the anode guide rod and anode steel claw are shown in the following table:

[0049]

[0050] It should be noted that the anode steel claw 7 in the present invention can be an existing model of anode steel claw (in this case, an axial hole can be opened on the crossbeam of the anode steel claw); it can also be an anode steel claw with a boss formed by integral casting (in this case, an axial hole is opened on the boss of the anode steel claw, and then the intermediate aluminum block is interference fit on the anode steel claw through the axial hole); it can also be an existing model of anode steel claw assembled with a boss through secondary processing (in this case, an axial hole can be opened on the assembled boss, and then the intermediate aluminum block is interference fit on the anode steel claw through the axial hole).

[0051] like Figure 3 As shown, the conductive device's joint surface exhibits a clear interface. Observation of this interface reveals that some steel has penetrated into the aluminum rod. This interpenetration between the aluminum rod and the steel claws allows the two to mechanically connect as a single unit, effectively enhancing the bond strength between the aluminum rod and the steel claws. Simultaneously, the close contact between the aluminum-steel mechanical connection creates significant contact stress between the aluminum rod and the steel claws, even under the constraints of interference stress. This significant contact stress not only causes interpenetration between the two materials but also generates radial friction. The resulting metallurgical bond further enhances the connection strength, securing the steel claws to the aluminum rod and achieving the aluminum-steel mechanical connection. These two connection methods, working together, not only enhance the maximum strength of the connection but also significantly extend the service life of the connector, reducing replacement and subsequent maintenance costs.

[0052] The cross-sections of the central axis hole and the middle aluminum block of the present invention can be circular, square or any other polygonal shape.

[0053] Example 2

[0054] An energy-saving anode conductive device for aluminum electrolysis, and a manufacturing method thereof are as follows:

[0055] 1) According to the actual working conditions of the anode conductive device, the original size model was established, and the outer diameter of the anode guide rod was 142.00 mm, the inner diameter of the shaft hole was 29.89 mm (the inner diameter of the shaft hole was obtained by subtracting the interference fit from the outer diameter of the anode guide rod), and the outer diameter of the shaft hole was 43.00 mm;

[0056] 2) The design calculation model of aluminum-steel cylindrical interference connection is established based on the relevant performance parameters of the anode guide rod and the anode steel claw, and the relationship between the interference and contact stress is obtained. 4 ×δ / 29MPa; Based on the actual working conditions of aluminum-steel interference joint, the finite element model of aluminum-steel interference joint was established using finite element analysis software, and the model boundary conditions were set according to the actual assembly working conditions;

[0057] 3) Under the condition of the optimal interference δ = 0.50 mm, the first average contact stress value of the calculation model is 170.834 MPa and the second average contact stress value of the finite element model is 169.218 MPa. The deviation between the first stress value and the second stress value is calculated to be 1.616 MPa, and the ratio of the difference to the first average contact stress is 0.946%, indicating that the calculation of the simulation model is credible;

[0058] 4) According to the actual working conditions, the minimum joint length l is calculated based on the weight G of the anode steel claw and carbon block, the friction coefficient μ of the anode guide rod and the anode steel claw, and the inner diameter d0 of the shaft hole. min ;

[0059] 5) According to the size of the middle hole in 1), the shaft hole is opened on the anode steel claw (the inner diameter of the shaft hole is 29.89mm and the outer diameter of the shaft hole is 43.00mm), and then according to the minimum connection length l min ×(3~500) Process the intermediate aluminum block, assemble it on the anode steel claw through the shaft hole in an interference fit manner, grind the lower end surface of the anode guide rod and then connect it to the intermediate aluminum block by self-propagating welding to achieve efficient and rapid full-melting welding, and then assemble the carbon block on the anode steel claw;

[0060] 6) Spray metal powder (one or more of aluminum powder, copper powder or zinc powder) at the junction of the anode guide rod, the middle aluminum block and the anode steel claw to improve the bonding strength of the aluminum-steel connection and increase the conductive area;

[0061] Among them, the relevant performance parameters of the anode guide rod and anode steel claw are shown in the following table:

[0062]

[0063] The above description is only a preferred embodiment of the present invention and does not limit the implementation mode and protection scope of the present invention. For those skilled in the art, it should be aware that all solutions obtained by equivalent substitutions and obvious changes made using the description and illustrations of the present invention should be included in the protection scope of the present invention.

Claims

1. A method for manufacturing an energy-saving anode conductive device for aluminum electrolysis, characterized in that: The following steps are involved: 1) Obtain the outer diameter of the anode guide rod, and obtain the inner diameter of the shaft hole by subtracting the interference from the outer diameter of the anode guide rod; 2) The design calculation model of aluminum-steel cylindrical interference connection is established based on the relevant performance parameters of the anode guide rod and the anode steel claw, and the relationship between the interference amount and the contact stress is obtained; according to the actual working conditions of the aluminum-steel interference connection, the finite element model of the aluminum-steel interference connection is established using finite element analysis software, and the model boundary conditions are set according to the actual assembly working conditions; 3) Under the condition of the same interference, the first average contact stress value of the calculation model and the second average contact stress value of the finite element model are respectively obtained, and the deviation value between the first stress value and the second stress value is calculated to verify the calculation accuracy of the simulation model; 4) According to the actual working conditions, the minimum connection length l is calculated based on the weight G of the anode steel claw and the carbon block, the friction coefficient μ of the anode guide rod and the anode steel claw, and the inner diameter d0 of the shaft hole. min ; 5) According to the size of the middle axis hole in 1), open the axis hole on the anode steel claw, and then according to the minimum connection length l min ×(3~500) Process the intermediate aluminum block, assemble the intermediate aluminum block on the anode steel claw through the shaft hole in an interference fit manner, weld the anode guide rod to the intermediate aluminum block, and then assemble the carbon block on the anode steel claw; 6) Spray metal powder at the junction of the anode guide rod, the middle aluminum block and the anode steel claw to improve the bonding strength of the aluminum-steel connection and increase the conductive area.

2. The manufacturing method according to claim 1, characterized in that: If the ratio of the deviation value to the first average contact stress value in step 3) is lower than 5%, the simulation model and the second average contact stress value are credible.

3. The manufacturing method according to claim 1, characterized in that: The minimum bonding length in step 4) must satisfy the following requirement: after the anode guide rod is fixed under the interference fit, the anode steel claw and the anode guide rod do not slide relative to each other under the combined effect of the anode steel claw and the carbon block's own gravity.

4. The manufacturing method according to claim 1, characterized in that: In step 5), the shaft hole can be directly opened on the crossbeam of the existing model anode steel claw.

5. The manufacturing method according to claim 1, characterized in that: In step 5), an axial hole may be provided on the boss of the anode steel claw with boss formed by integral casting.

6. The manufacturing method according to claim 1, characterized in that: In step 5), a boss can be firstly assembled on the crossbeam of the existing model of anode steel claw, and then an axial hole can be opened on the boss.

7. The manufacturing method according to claim 1, characterized in that: In step 5), the lower end surface of the anode guide rod may be firstly polished and then connected to the middle aluminum block by self-propagating welding to achieve efficient and rapid full-melt welding.

8. The manufacturing method according to claim 1, characterized in that: In step 6), the metal powder is selected from one or more of aluminum powder, copper powder or zinc powder.

9. An energy-saving anode conductive device for aluminum electrolysis, characterized in that: The method according to any one of claims 1 to 8 is used for manufacturing.

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