Roasting starting method of novel continuous anode aluminum electrolysis cell

Abstract

The invention discloses a roasting starting method of a novel continuous anode aluminum electrolysis cell. The method comprises the steps that a conducting medium, a supporting disc and an anode frame sleeve are sequentially arranged in the aluminum electrolysis cell; anode paste with a first preset height is added into the anode frame sleeve, and a current shunt is arranged on the side face of the anode frame sleeve; filling petroleum coke in a gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell, and introducing direct current to start roasting; after the roasting time reaches a first preset time, dismounting the current diverter, and carrying out conductivity enhancement treatment on the anode cone; after the temperature of the cathode carbon block reaches a first preset temperature, the petroleum coke is removed, and a gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell is filled with cryolite; and when the first average cone height of the anode cone reaches a second preset height and the temperature of the cathode carbon block reaches a second preset temperature, roasting is completed, and the aluminum electrolysis cell is started. According to the technical scheme provided by the invention, the quality of the anode cone generated during roasting starting of the novel continuous anode aluminum electrolysis cell can be improved.

Description

Technical Field

[0001] This application belongs to the technical field of roasting and starting of aluminum electrolytic cells, and particularly relates to a roasting and starting method for a new type of continuous anode aluminum electrolytic cell. Background Art

[0002] Currently, electrolyzing alumina is the main production method for preparing metallic aluminum in industry, and roasting and starting is the first step for an electrolytic cell to be put into normal operation. The main roasting methods for aluminum electrolytic cells are: coke particle roasting, aluminum liquid roasting, and gas roasting. For the new type of continuous anode aluminum electrolytic cell, since the conductive steel bar structure of side insertion or top insertion is cancelled, it is not only difficult to ensure the uniformity of current distribution during the roasting process, but also difficult to ensure that the anode cone formed by roasting the anode paste meets the requirements in terms of height and uniformity. Using the gas roasting method in the new type of continuous anode aluminum electrolytic cell will cause the problem of uncontrollable heating gradient, resulting in the abnormal shape of the anode cone formed by roasting. Using the conventional coke particle roasting will cause the problem of lack of internal heat conduction path, resulting in the difficulty in meeting the strength standard of the sintered cone. Based on this, how to improve the quality of the anode cone generated during the roasting and starting of the new type of continuous anode aluminum electrolytic cell is a technical problem to be solved urgently. Summary of the Invention

[0003] The embodiments of this application provide a roasting and starting method for a new type of continuous anode aluminum electrolytic cell, which can further improve the quality of the anode cone generated during the roasting and starting of the new type of continuous anode aluminum electrolytic cell.

[0004] Other features and advantages of this application will become apparent through the following detailed description, or be learned partially through the practice of this application.

[0005] According to some embodiments of the present application, a baking and starting method for a new type of continuous anode aluminum electrolysis cell is provided, characterized in that the method includes: sequentially arranging a conductive medium, a support plate and an anode frame sleeve in the aluminum electrolysis cell; adding anode paste to a first preset height in the anode frame sleeve, and arranging a current shunt on the side of the anode frame sleeve, the current shunt being used to assist the anode paste and the conductive medium in conducting electricity; filling petroleum coke in the gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell, and introducing direct current into the aluminum electrolysis cell to start baking, the petroleum coke being used for heat preservation and absorbing the asphalt smoke generated during baking; when the baking time reaches a first preset time, removing the current shunt, and performing a conductive enhancement treatment on the anode cone formed after baking the anode paste; when the temperature of the cathode carbon block of the aluminum electrolysis cell reaches a first preset temperature, removing the petroleum coke, and filling cryolite in the gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell; determining a first average cone height of the anode cone in the anode frame sleeve, and when the first average cone height reaches a second preset height and the temperature of the cathode carbon block reaches a second preset temperature, completing baking and starting the aluminum electrolysis cell.

[0006] In some embodiments of the present application, based on the foregoing solution, the sequentially arranging a conductive medium, a support plate and an anode frame sleeve in the aluminum electrolysis cell includes: laying a conductive medium with a preset thickness at the bottom of the aluminum electrolysis cell; placing a support plate above the conductive medium, the support plate being used to support the anode frame sleeve and separate the conductive medium from the anode paste; placing the anode frame sleeve on the support plate, and laying a ceramic fiber board between the support plate and the anode frame sleeve, the ceramic fiber board being used to increase the sealing performance of the anode frame sleeve and prevent current from directly flowing through the anode frame sleeve into the support plate and the conductive medium.

[0007] In some embodiments of the present application, based on the foregoing solution, the material of the conductive medium is granular carbon material, and the preset thickness is 30 mm to 60 mm.

[0008] In some embodiments of the present application, based on the foregoing solution, one end of the current shunt is connected to the side of the anode frame sleeve, and the other end is connected to the steel bar part of the cathode of the aluminum electrolysis cell.

[0009] In some embodiments of the present application, based on the foregoing solution, the conductive enhancement treatment for the anode cone formed after calcining the anode paste includes: measuring the first cone height corresponding to the anode cone in different anode frame sleeve regions respectively, and determining the second average cone height of the anode cone based on the first cone height; determining the anode frame sleeve region where the first cone height is lower than the second average cone height as the low-conductivity region; inserting aluminum rods into the low-conductivity region to enhance the conductivity of the anode cone in the low-conductivity region.

[0010] In some embodiments of the present application, based on the foregoing solution, the determination of the first average cone height of the anode cone in the anode frame sleeve includes: when the calcination time reaches the second preset time, measuring the second cone height corresponding to the anode cone in different anode frame sleeve regions respectively, and determining the first average cone height of the anode cone based on the second cone height.

[0011] In some embodiments of the present application, based on the foregoing solution, the startup of the aluminum electrolytic cell includes: lifting the anode cone, pouring liquid electrolyte into the aluminum electrolytic cell until the height of the liquid electrolyte in the aluminum electrolytic cell reaches the third preset height and the cell voltage of the aluminum electrolytic cell reaches the preset voltage, completing the startup of the aluminum electrolytic cell.

[0012] In some embodiments of the present application, based on the foregoing solution, the first preset height is 500 mm to 800 mm, and the second preset height is 400 mm to 600 mm.

[0013] In some embodiments of the present application, based on the foregoing solution, the first preset temperature is 800 °C, and the second preset temperature is 900 °C.

[0014] In some embodiments of the present application, based on the foregoing solution, the shunt ratio of the current shunt is greater than or equal to 70%.

[0015] Based on the technical solution proposed in the present application, by filling petroleum coke in the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell, on the one hand, the temperature in the anode frame sleeve can be maintained by using petroleum coke during calcination, and on the other hand, the asphalt smoke generated during calcination can be absorbed by the petroleum coke. In this way, not only can the unorganized emission of asphalt smoke be effectively reduced, the environmental pollution be reduced, but also the quality of the anode cone generated during the calcination of the new continuous anode aluminum electrolytic cell can be ensured; when the calcination time reaches the first preset time, the conductive enhancement treatment for the anode cone formed after calcining the anode paste can improve the current distribution during the calcination process, contribute to more precisely controlling the calcination conditions, so that the current distribution inside the anode paste is uniform and the heat conduction is uniform during calcination, thereby improving the quality of the anode cone.

[0016] It should be understood that the above general description and the following detailed description are merely exemplary and explanatory, and do not limit this application. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The drawings herein are incorporated into and constitute a part of this specification, showing embodiments consistent with this application, and are used together with the specification to explain the principles of this application. Obviously, the drawings in the following description are only some embodiments of this application, and those of ordinary skill in the art can obtain other drawings based on these drawings without creative efforts. In the drawings:

[0018] Figure 1 shows a flowchart of the baking start-up method of the new continuous anode aluminum electrolytic cell in an embodiment of this application;

[0019] Figure 2 shows a schematic internal diagram of the new continuous anode aluminum electrolytic cell in an embodiment of this application. DETAILED DESCRIPTION OF THE EMBODIMENTS

[0020] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the drawings in the embodiments of this application. Obviously, the described embodiments are only a part of the embodiments of this application, rather than all the embodiments. All other embodiments obtained by those of ordinary skill in the art without creative efforts based on the embodiments in this application belong to the scope of protection of this application.

[0021] In addition, the described features, structures, or characteristics can be combined in any suitable manner in one or more embodiments. In the following description, many specific details are provided to give a full understanding of the embodiments of this application. However, those skilled in the art will realize that the technical solutions of this application can be practiced without one or more of the specific details, or other methods, components, devices, steps, etc. can be used. In other cases, well-known methods, devices, implementations, or operations are not shown or described in detail to avoid obscuring various aspects of this application.

[0022] The block diagrams shown in the drawings are only functional entities and do not necessarily correspond to physically independent entities. That is, these functional entities can be implemented in software form, or in one or more hardware modules or integrated circuits, or in different networks and / or processor devices and / or microcontroller devices.

[0023] The flowcharts shown in the accompanying drawings are merely illustrative and not necessarily include all the content and operations / steps, nor are they necessarily executed in the order described. For example, some operations / steps can be decomposed, while some operations / steps can be combined or partially combined. Therefore, the actual execution order may change according to the actual situation.

[0024] It should also be noted that the terms "first", "second", etc. in the description, claims and above-mentioned accompanying drawings of this application are used to distinguish similar objects and do not necessarily describe a specific order or sequence. It should be understood that the objects used in this way can be interchanged under appropriate circumstances so that the embodiments of this application described here can be implemented in an order other than those illustrated or described.

[0025] To enable those skilled in the art to better understand this application, the following will briefly introduce the relevant background of the new continuous anode aluminum electrolytic cell and its baking start-up method.

[0026] Currently, electrolyzing alumina is the main production method for preparing metallic aluminum in industry, and baking start-up is the first step for the electrolytic cell to be put into normal operation. The baking methods of aluminum electrolytic cells mainly include three methods: coke particle baking, molten aluminum baking and gas baking. For the new continuous anode aluminum electrolytic cell, since the conductive steel bar structure of side insertion or top insertion is cancelled, it is not only difficult to ensure the uniformity of current distribution during the baking process, but also difficult to ensure that the anode cone formed by baking the anode paste meets the requirements in terms of height and uniformity. Using the gas baking method in the new continuous anode aluminum electrolytic cell will cause the problem of uncontrollable heating gradient, resulting in the abnormal shape of the anode cone formed by baking. Using the conventional coke particle baking will cause the problem of lack of internal heat conduction path, resulting in the difficulty in meeting the standard of the sintered cone strength. Based on this, the inventor of this application proposed a baking start-up method for the new continuous anode aluminum electrolytic cell to improve the quality of the anode cone generated during the baking start-up of the new continuous anode aluminum electrolytic cell.

[0027] Next, in combination with Figure 1 , a baking start-up method for the new continuous anode aluminum electrolytic cell proposed in this application will be elaborated in detail.

[0028] Please refer to Figure 1 , which shows a flowchart of the baking start-up method of the new continuous anode aluminum electrolytic cell in an embodiment of this application. The method can at least include the following steps 110 to step 160:

[0029] Step 110, sequentially arrange conductive media, support plates and anode frame sleeves in the aluminum electrolytic cell.

[0030] Step 120: Add anode paste to the anode frame sleeve to a first preset height, and install a current diverter on the side of the anode frame sleeve, where the current diverter is used to assist the anode paste and the conductive medium in conducting electricity.

[0031] Step 130: Fill the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell with petroleum coke, and pass direct current into the aluminum electrolytic cell to start roasting. The petroleum coke is used for heat preservation and to absorb the pitch fumes generated during roasting.

[0032] Step 140: After the roasting time reaches the first preset time, remove the current diverter, and perform a conductive enhancement treatment on the anode cone formed after roasting the anode paste.

[0033] Step 150: After the temperature of the cathode carbon block of the aluminum electrolytic cell reaches the first preset temperature, remove the petroleum coke, and fill the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell with cryolite.

[0034] Step 160: Determine the first average cone height of the anode cone in the anode frame sleeve. When the first average cone height reaches the second preset height and the temperature of the cathode carbon block reaches the second preset temperature, the roasting is completed, and the aluminum electrolytic cell is started.

[0035] In this application, the first preset height can be 500 mm to 800 mm. For example, it can be 550 mm, or 650 mm, or 700 mm. The second preset height can be 400 mm to 600 mm. For example, it can be 450 mm, or 500 mm, or 550 mm. This application does not make specific limitations in this regard.

[0036] In this application, the first preset time can specifically be 72 hours, the first preset temperature can be 800 °C, and the second preset temperature can be 900 °C. This application does not make specific limitations in this regard.

[0037] In this application, after the anode paste and the petroleum coke are filled, a compaction treatment can also be performed. For example, a pneumatic ramming machine can be used for compaction treatment. The air pressure for compaction treatment can be greater than 0.5 MPa. Specifically, it can be 0.55 MPa, or 0.6 MPa.

[0038] In this application, the anode paste and the conductive medium have a relatively large resistance before roasting. Therefore, a current shunt is required to assist the anode paste and the conductive medium in conducting electricity at the initial stage of roasting, so as to improve the roasting effect and avoid the occurrence of uneven current, which may lead to the deformation of the anode cone formed by roasting and cause the start-up failure. One end of the current shunt is connected to the side of the anode frame sleeve, and the other end is connected to the steel bar part of the cathode of the aluminum electrolytic cell. Moreover, the shunt ratio of the current shunt needs to be greater than or equal to 70%. Specifically, for example, when the direct current passed during roasting is 20 kA, the current flowing through the current shunt is 14 kA.

[0039] In this application, by filling petroleum coke in the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell, on the one hand, the temperature inside the anode frame sleeve can be maintained by using the petroleum coke during roasting, and on the other hand, the asphalt fumes generated during roasting can be absorbed by the petroleum coke. In this way, not only can the unorganized emission of asphalt fumes be effectively reduced, the environmental pollution be reduced, but also the quality of the anode cone generated during the roasting of the new type of continuous anode aluminum electrolytic cell can be ensured. When the roasting time reaches the first preset time, a conductive enhancement treatment is performed on the anode cone formed after roasting the anode paste, which can improve the current distribution during the roasting process, contribute to more precise control of the roasting conditions, so that during roasting, the current distribution inside the anode paste is uniform and the heat conduction is uniform, thereby improving the quality of the anode cone.

[0040] In the above step 110, arranging the conductive medium, the support plate and the anode frame sleeve in the aluminum electrolytic cell in sequence can be specifically carried out according to the following steps 111 to 113:

[0041] Step 111, laying a conductive medium with a preset thickness at the bottom of the aluminum electrolytic cell.

[0042] Step 112, placing a support plate above the conductive medium. The support plate is used to support the anode frame sleeve and separate the conductive medium from the anode paste.

[0043] Step 113, placing the anode frame sleeve on the support plate and laying a ceramic fiber board between the support plate and the anode frame sleeve. The ceramic fiber board is used to increase the sealing performance of the anode frame sleeve and prevent the current from directly flowing through the anode frame sleeve into the support plate and the conductive medium.

[0044] Please refer to the following Figure 2, which shows the internal schematic diagram of the new continuous anode aluminum electrolytic cell in an embodiment of the present application. As shown in the figure, a conductive medium 204 with a preset thickness is laid at the bottom of the new continuous anode aluminum electrolytic cell 200. A support plate 205 is placed above the conductive medium 204. The support plate 205 can be used to support the anode frame sleeve 202 and separate the conductive medium 204 from the anode paste 201. The anode frame sleeve 202 is placed on the support plate 205, and a ceramic fiber board 206 is laid between the support plate 205 and the anode frame sleeve 202 to prevent current from directly flowing through the anode frame sleeve 202 into the support plate 205 and the conductive medium 204. Petroleum coke 203 is filled between the anode frame sleeve 202 and the inner wall of the aluminum electrolytic cell 200, and the anode paste 201 is filled inside the anode frame sleeve 202.

[0045] In the present application, the material of the conductive medium is granular carbon material. For example, it can be calcined coke particles, or it can be graphite scraps, or it can be a mixture of calcined coke particles and graphite scraps. The mixing ratio of the mixture can be adjusted within the range of 60%-80% of calcined coke particles (20%-40% of graphite scraps) according to requirements, and the total proportion of the two is always 100%. The particle size of the carbon material can be 1 mm to 6 mm, specifically it can be 3 mm, or it can be 4 mm, or it can be 5 mm. The preset thickness is 30 mm to 60 mm, specifically it can be 35 mm, or it can be 45 mm, or it can be 55 mm. The present application does not make specific limitations on this.

[0046] In the present application, the material of the support plate can be iron or stainless steel. The thickness of the support plate can be 3 mm to 6 mm, specifically it can be 4 mm, or it can be 5 mm. The material of the anode frame sleeve can be aluminum or aluminum alloy. The thickness of the anode frame sleeve can be 10 mm to 15 mm, specifically it can be 11 mm, or it can be 13 mm. The present application does not make specific limitations on this.

[0047] In the present application, the number of the anode frame sleeves can be set according to the size of the cell type of the aluminum electrolytic cell. The thickness of the ceramic fiber board can be 10 mm to 50 mm, specifically it can be 20 mm, or it can be 30 mm, or it can be 40 mm. The present application does not make specific limitations on this.

[0048] In the present application, by laying a ceramic fiber board between the support plate and the anode frame sleeve, it is possible to prevent current from directly flowing from the anode frame sleeve into the support plate and the conductive medium, ensuring that the current is conducted from the anode paste as designed, improving the energy utilization efficiency during the baking and start-up process of the aluminum electrolysis cell. In addition, setting the ceramic fiber board can also fill the gap between the anode frame sleeve and the support plate, thereby preventing the softened anode paste or tar after baking from leaking out through the gap, and also preventing asphalt fumes from emerging from the gap, and further effectively improving the quality of the anode cone generated during the baking and start-up of the new continuous anode aluminum electrolysis cell.

[0049] In step 140 above, the conductive enhancement treatment of the anode cone formed after baking the anode paste can be specifically carried out according to the following steps 141 to step 143:

[0050] Step 141, measure the first cone height corresponding to the anode cone in different anode frame sleeve regions respectively, and based on the first cone height, determine the second average cone height of the anode cone.

[0051] Step 142, determine the anode frame sleeve region where the first cone height is lower than the second average cone height as the low-conductivity region.

[0052] Step 143, insert aluminum bars into the low-conductivity region to enhance the conductivity of the anode cone in the low-conductivity region.

[0053] In the present application, when measuring the first cone height corresponding to the anode cone in different anode frame sleeve regions respectively, specifically, a measuring tool can be inserted into different anode frame sleeve regions, and the insertion height of different anode frame sleeve regions is measured. By subtracting the insertion height of different anode frame sleeve regions from the first preset height, the first cone height of different anode frame sleeve regions is obtained.

[0054] In the present application, the measuring tool can be made of stainless steel or brass, and its end can be ground into a pointed shape with a diameter of 6 mm to 10 mm, specifically 7 mm, or 8 mm, or 9 mm, and a length of 1000 mm to 1800 mm, specifically 1200 mm, or 1500 mm, or 1600 mm. The diameter of the aluminum bar is 6 mm to 15 mm, specifically 7 mm, or 9 mm, or 12 mm, and a length of 1000 mm to 1800 mm, specifically 1300 mm, or 1600 mm, or 1700 mm. In this regard, the present application does not make specific limitations.

[0055] In this application, by measuring the first cone height of the anode cone in different anode frame sleeve areas and comparing it with the second average cone height, low-conductivity areas with poor conductivity can be accurately identified, providing data support for subsequent conductive enhancement processing. Inserting aluminum bars in the low-conductivity areas to enhance conductivity can prompt the anode paste to heat up and sinter to form the anode cone under the condition of enhanced conductivity, further improving the quality of the anode cone generated during the roasting start-up of the novel continuous anode aluminum electrolytic cell; in addition, since the aluminum bars will melt at high temperatures, there is no need to perform the bar pulling operation after the anode paste is sintered. In this way, a large amount of unorganized emissions of asphalt fumes caused by the bar pulling operation can be avoided.

[0056] In step 160 above, to determine the first average cone height of the anode cone in the anode frame sleeve, specifically, it can be executed according to the following step 161:

[0057] Step 161, when the roasting time reaches the second preset time, measure the second cone height corresponding to the anode cone in different anode frame sleeve areas respectively, and based on the second cone height, determine the first average cone height of the anode cone.

[0058] In this application, the second preset time can be 100 hours to 150 hours. Specifically, it can be 110 hours, or 120 hours, or 140 hours. In this regard, this application does not make specific limitations.

[0059] In this application, by measuring the second cone height of different anode frame sleeve areas, the current distribution uniformity during the roasting process can be intuitively reflected. And by determining the first average cone height of the anode cone through the second cone height, the overall sintering situation of the anode cone can be reflected, which is used to judge whether the current roasting progress meets the expectation and provides data support for the judgment of the start-up conditions of the subsequent aluminum electrolytic cell.

[0060] In step 160 above, to start the aluminum electrolytic cell, specifically, it can be executed according to the following step 162:

[0061] Step 162, lift the anode cone, pour liquid electrolyte into the aluminum electrolytic cell until the height of the liquid electrolyte in the aluminum electrolytic cell reaches the third preset height and the cell voltage of the aluminum electrolytic cell reaches the preset voltage, and complete the start-up of the aluminum electrolytic cell.

[0062] In this application, the third preset height needs to be greater than or equal to 300 mm. Specifically, it can be 350 mm, or 400 mm, or 450 mm. The preset voltage needs to be less than or equal to 10 V. Specifically, it can be 7 V, or 8 V, or 9 V. This application does not make specific limitations in this regard.

[0063] In the present application, after the start-up conditions of the aluminum electrolytic cell are met, the anode cone can be lifted, and a liquid electrolyte with a third preset height can be poured into the aluminum electrolytic cell. At this time, as the anode cone rises, the cell voltage of the electrolytic cell will gradually increase until it reaches the preset voltage, and then the lifting of the anode cone is stopped, completing the start-up of the aluminum electrolytic cell. In this way, through clear operation steps and control conditions, the aluminum electrolytic cell can reach the start-up state quickly and stably, improving the overall production efficiency.

[0064] To enable those skilled in the art to better understand the present application, next, a baking start-up method for a novel continuous anode aluminum electrolytic cell proposed in the present application will be described in conjunction with some specific embodiments.

[0065] Example 1: A mixture of calcined coke grains and graphite fragments is laid on the bottom of the novel continuous anode aluminum electrolytic cell as a conductive medium, with a mixing ratio of 60%:40%, a particle size of 2 mm to 4 mm, and a laying thickness of 40 mm. A stainless steel plate with a thickness of 3 mm is placed above the conductive medium as a support plate. A set of aluminum anode frame sleeves with a thickness of 10 mm is placed above the support plate. A ceramic fiber board with a thickness of 20 mm is laid between the anode frame sleeve and the support plate. An anode paste with a height of 500 mm is added into the anode frame sleeve. An anode paste compactor with a wind pressure of 0.55 MPa is used to compact the anode paste. The gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell is filled and compacted with petroleum coke. Four sets of current shunts are welded to the side of the anode frame sleeve, and the initial shunt ratio is 70%. A direct current of 20 kA is passed to start baking. After baking for 72 hours, the height of the anode cone is measured. Then, eight aluminum bars with a diameter of 8 mm and a length of 1200 mm are respectively inserted into the low-conductivity areas at the four corners of the anode frame sleeve to increase the conductivity. After 104 hours, the temperature of the cathode carbon block reaches 803 °C, and the petroleum coke is dug out and filled with cryolite. After 144 hours, the evaluated height of the anode cone is measured to be 413 mm, and the average temperature of the cathode carbon block is 916 °C, reaching the start-up conditions. The specific anode cone height and cathode carbon block temperature are shown in Table 1. Then, the anode cone is gradually lifted, and at the same time, 2 tons of liquid electrolyte is poured in. When the cell voltage rises to 10 V, the anode cone starts to work, and the aluminum electrolytic cell starts up successfully.

[0066]

[0067] Table 1

[0068] Example 2: Calcined coke particles with a particle size of 1 mm to 6 mm and a laying thickness of 30 mm are laid on the bottom of the new type of continuous anode aluminum electrolysis cell as a conductive medium. An iron plate with a thickness of 4 mm is placed above the conductive medium as a support plate, and 5 groups of aluminum anode frame sleeves with a thickness of 12 mm are placed above the support plate. A 30-mm-thick ceramic fiber board is laid between the anode frame sleeve and the support plate. Anode paste with a height of 600 mm is added into the anode frame sleeve, and a ramming machine with an air pressure of 0.5 MPa is used to ram the paste firmly. The gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell is filled with petroleum coke and compacted. 16 groups of current shunts are welded on the side of the anode frame sleeve, and the initial shunt ratio is 70%; 200 kA of direct current is passed in for baking. When baking reaches 72 hours, a special tool is used to measure the height of the anode cone. Then, 4 aluminum bars with a diameter of 10 mm and a length of 1500 mm are inserted into the low-conductivity areas at the four corners of the anode frame sleeve to increase the conductivity; after 104 hours, the temperature of the cathode carbon block reaches 828 °C, the petroleum coke is dug out and electrolyte powder is filled in; after 144 hours, the average height of the anode cone is measured to be 427 mm, and the average temperature of the cathode carbon block is 935 °C, reaching the start-up condition. The specific anode cone height and cathode carbon block temperature are shown in Table 2. Then, the anode cone is gradually lifted, and at the same time, 14 tons of liquid electrolyte is poured in. When the cell voltage rises to 8 V, the anode cone starts to work, and the aluminum electrolysis cell starts successfully.

[0069]

[0070]

[0071] Table 2

[0072] Example 3: Graphite fragments are laid on the bottom of the new type of continuous anode aluminum electrolytic cell as the conductive medium, with a particle size of 1 mm to 5 mm and a laying thickness of 60 mm. An iron plate with a thickness of 6 mm is placed above the conductive medium as the support plate, and 8 sets of aluminum anode frame sleeves with a thickness of 15 mm are placed above the support plate. A 50-mm ceramic fiber board is laid between the anode frame and the support plate. Anode paste with a height of 800 mm is added into the anode frame sleeve, and a ramming machine with an air pressure of 0.55 MPa is used to ram the paste firmly. The gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell is filled with petroleum coke and compacted. 20 sets of current shunts are welded on the side of the anode frame sleeve, and the initial shunt ratio is 70%; 300 kA of direct current is passed in to start roasting. When roasting reaches 72 hours, a special tool is used to measure the height of the anode cone, and then 6 aluminum rods with a diameter of 15 mm and a length of 1600 mm are inserted into the low-conductivity areas at the four corners of the anode frame sleeve to increase the conductivity; after 104 hours, the temperature of the cathode carbon block reaches 811 °C, the petroleum coke is dug out and electrolyte powder is filled; after 144 hours, the average height of the anode cone is measured to be 418 mm, and the average temperature of the cathode carbon block is 928 °C, reaching the start-up condition. The specific anode cone height and cathode carbon block temperature are shown in Table 3. Then, the anode cone is gradually lifted, and at the same time, 18 tons of liquid electrolyte is poured in. When the cell voltage rises to 9 V, the anode cone starts to work, and the aluminum electrolytic cell starts successfully.

[0073]

[0074] Table 3

[0075] As can be seen from the above Examples 1 to 3, through the roasting and start-up method of the new type of continuous anode aluminum electrolytic cell proposed in this application, the height uniformity of the sintered anode cone is relatively good, and the cathode carbon block can reach the temperature required for start-up, showing a good start-up effect.

[0076] Correspondingly, in Comparative Example 1, the same aluminum electrolytic cell as in Example 1, the same roasting and start-up method and materials are used, that is, a mixture of calcined coke particles and graphite fragments is laid on the bottom of the new type of continuous anode aluminum electrolytic cell as the conductive medium, with a mixing ratio of 60%:40%, a particle size of 2 mm to 4 mm, and a laying thickness of 40 mm. A stainless steel plate with a thickness of 3 mm is placed above the conductive medium as the support plate, and 1 set of aluminum anode frame sleeves with a thickness of 10 mm is placed above the support plate. A 20-mm ceramic fiber board is laid between the anode frame sleeve and the support plate. Anode paste with a height of 500 mm is added into the anode frame sleeve, and a ramming machine with an air pressure of 0.55 MPa is used to compact the anode paste. The gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell is filled with petroleum coke and compacted. 4 sets of current shunts are welded on the side of the anode frame sleeve, and the initial shunt ratio is 70%; 20 kA of direct current is passed in to start roasting.

[0077] However, in Comparative Example 1, the operation of using an inserted aluminum rod for conductive enhancement treatment was not carried out. After 144 hours, the average height of the sintered anode cone was 364 mm, and the temperature of the cathode carbon block was 913 °C, failing to meet the start-up conditions. Therefore, it shows that the technology proposed in this application can improve the quality of the anode cone produced by roasting.

[0078] In Comparative Example 2, the same aluminum electrolytic cell as in Example 2 was used, with the same roasting start-up method and materials. Specifically, calcined coke particles were laid on the bottom of the new type of continuous anode aluminum electrolytic cell as the conductive medium, with a particle size of 1 mm to 6 mm and a laying thickness of 30 mm. An iron plate with a thickness of 4 mm was placed above the conductive medium as a support plate, and 5 groups of aluminum anode frame sleeves with a thickness of 12 mm were placed above the support plate. A 30-mm-thick ceramic fiber board was laid between the anode frame sleeve and the support plate. An anode paste with a height of 600 mm was added into the anode frame sleeve, and a rammer with an air pressure of 0.5 MPa was used to compact the paste. 16 groups of current shunts were welded on the side of the anode frame sleeve, and the initial shunt ratio was 70%; 200 kA of direct current was passed in to start roasting. When roasting reached 72 hours, a special tool was used to measure the height of the anode cone, and then 4 aluminum rods with a diameter of 10 mm and a length of 1500 mm were inserted into the low-conductivity areas at the 4 corners of the anode frame sleeve to increase the conductivity.

[0079] However, in Comparative Example 2, the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell was not filled with petroleum coke. After 144 hours, the average height of the anode cone was 387 mm, and the temperature of the cathode carbon block was only 885 °C, failing to meet the start-up conditions. Moreover, during the roasting process, a large amount of pitch fume was generated. Therefore, it shows that the technical solution proposed in this application can not only improve the quality of the anode cone, but also absorb the pitch fume generated during the sintering process.

[0080] In Comparative Example 3, the same aluminum electrolytic cell as in Example 3 was used, with the same roasting start-up method and materials. Specifically, graphite fragments were laid on the bottom of the new type of continuous anode aluminum electrolytic cell as the conductive medium, with a particle size of 1 mm to 5 mm and a laying thickness of 60 mm. An iron plate with a thickness of 6 mm was placed above the conductive medium as a support plate, and 8 groups of aluminum anode frames with a thickness of 15 mm were placed above the support plate. A 50-mm-thick ceramic fiber board was laid between the anode frame and the support plate. An anode paste with a height of 800 mm was added into the anode frame sleeve, and a rammer with an air pressure of 0.55 MPa was used to compact the paste. The gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell was filled with petroleum coke and compacted; 300 kA of direct current was passed in to start roasting. When roasting reached 72 hours, a special tool was used to measure the height of the anode cone, and then 6 aluminum rods with a diameter of 15 mm and a length of 1600 mm were inserted into the low-conductivity areas at the 4 corners of the anode frame sleeve to increase the conductivity; after 104 hours, the temperature of the cathode carbon block reached 811 °C, and after the petroleum coke was dug out, electrolyte powder was filled in.

[0081] However, in Comparative Example 3, a smaller number of current shunts were connected to the outside of the anode frame sleeve, and the initial shunt ratio was set at 40%. After the start of baking, uneven current distribution occurred, resulting in a deformed anode cone formed during baking. In the area with a large current, sintering and shrinkage were faster, leading to shrinkage cracks in the anode cone. The built-in conductor inside melted and leaked out, resulting in startup failure. Therefore, it can be shown that the technical solution proposed in this application can effectively assist in shunting, avoid uneven current distribution, and ensure the safety of the baking startup process.

[0082] In Comparative Example 4, the same aluminum electrolysis cell as in Example 2, the same baking startup method and materials were used. Specifically, calcined coke particles were laid on the bottom of the new type of continuous anode aluminum electrolysis cell as the conductive medium, with a particle size of 1 mm to 6 mm and a laying thickness of 30 mm. No support plate was placed above the conductive medium, and 5 groups of aluminum anode frame sleeves with a thickness of 12 mm were directly placed. A 30-mm-thick ceramic fiber board was laid between the anode frame sleeve and the support plate. Anode paste with a height of 600 mm was added into the anode frame sleeve, and a rammer with an air pressure of 0.5 MPa was used to compact the paste. 16 groups of current shunts were welded to the side of the anode frame sleeve, and the initial shunt ratio was 70%. A direct current of 200 kA was passed to start baking. When baking reached 72 hours, a special tool was used to measure the height of the anode cone. Then, 4 aluminum bars with a diameter of 10 mm and a length of 1500 mm were inserted into the low-conductivity areas at the four corners of the anode frame sleeve to increase the conductivity.

[0083] However, in Comparative Example 4, the support plate above the conductive medium was removed. At 144 hours, the average height of the anode cone was 372 mm, and the temperature of the cathode carbon block surface was only 844 °C, failing to reach the startup condition. Therefore, it shows that the technical solution proposed in this application can effectively improve the quality of the anode cone formed during baking.

[0084] For the results of the startup condition data between Comparative Examples 1 to 4 and Examples 1 to 3 respectively, please refer to Table 4.

[0085]

[0086]

[0087] Table 4

[0088] Based on the technical solution proposed in this application, by filling petroleum coke in the gap between the anode frame sleeve and the inner wall of the aluminum electrolytic cell, on the one hand, the temperature inside the anode frame sleeve can be maintained by using petroleum coke during roasting, and on the other hand, the asphalt fumes generated during roasting can be absorbed by the petroleum coke. In this way, not only can the unorganized emission of asphalt fumes be effectively reduced, the environmental pollution be reduced, but also the quality of the anode cone generated during the roasting of the new type of continuous anode aluminum electrolytic cell can be ensured; when the roasting time reaches the first preset time, a conductive enhancement treatment is carried out on the anode cone formed after roasting the anode paste, which can improve the current distribution during roasting, contribute to more accurate control of the roasting conditions, so that the current distribution inside the anode paste is uniform and the heat conduction is uniform during roasting, thereby improving the quality of the anode cone.

[0089] The above are only the embodiments of the present application and are not intended to limit the present application. For those skilled in the art, various changes and modifications can be made to the present application. Any modification, equivalent replacement, improvement, etc. made within the spirit and principle of the present application shall be included within the scope of the claims of the present application.

Claims

1. A baking and starting method for a new type of continuous anode aluminum electrolysis cell, characterized in that, The method includes: Sequentially arranging a conductive medium, a support plate, and an anode frame sleeve in the aluminum electrolysis cell; Adding anode paste to a first preset height in the anode frame sleeve, and arranging a current shunt on the side of the anode frame sleeve, where the current shunt is used to assist the anode paste and the conductive medium in conducting electricity; Filling petroleum coke in the gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell, and introducing direct current into the aluminum electrolysis cell to start baking. The petroleum coke is used for heat preservation and absorbs the asphalt fumes generated during baking; When the baking time reaches a first preset time, removing the current shunt, and performing a conductive enhancement treatment on the anode cone formed after baking the anode paste; When the temperature of the cathode carbon block of the aluminum electrolysis cell reaches a first preset temperature, removing the petroleum coke, and filling cryolite in the gap between the anode frame sleeve and the inner wall of the aluminum electrolysis cell; Determining a first average cone height of the anode cone in the anode frame sleeve. When the first average cone height reaches a second preset height and the temperature of the cathode carbon block reaches a second preset temperature, the baking is completed, and the aluminum electrolysis cell is started.

2. The method according to claim 1, characterized in that The sequentially arranging a conductive medium, a support plate, and an anode frame sleeve in the aluminum electrolysis cell includes: Laying a conductive medium with a preset thickness at the bottom of the aluminum electrolysis cell; Placing a support plate above the conductive medium. The support plate is used to support the anode frame sleeve and separate the conductive medium from the anode paste; Placing an anode frame sleeve on the support plate, and laying a ceramic fiber board between the support plate and the anode frame sleeve. The ceramic fiber board is used to increase the sealing performance of the anode frame sleeve and prevent current from directly flowing through the anode frame sleeve into the support plate and the conductive medium.

3. The method according to claim 2, wherein The material of the conductive medium is granular carbon material, and the preset thickness is 30 mm to 60 mm.

4. The method according to claim 1, wherein One end of the current shunt is connected to the side of the anode frame sleeve, and the other end is connected to the steel bar part of the cathode of the aluminum electrolysis cell.

5. The method according to claim 1, wherein The performing a conductive enhancement treatment on the anode cone formed after baking the anode paste includes: Measuring the first cone height corresponding to different regions of the anode frame sleeve of the anode cone, and determining a second average cone height of the anode cone based on the first cone height; Determining the regions of the anode frame sleeve where the first cone height is lower than the second average cone height as low-conductivity regions; Inserting aluminum bars into the low-conductivity regions to enhance the conductivity of the anode cone in the low-conductivity regions.

6. The method according to claim 1, wherein The determining a first average cone height of the anode cone in the anode frame sleeve includes: When the baking time reaches a second preset time, measuring the second cone height corresponding to different regions of the anode frame sleeve of the anode cone, and determining the first average cone height of the anode cone based on the second cone height.

7. The method according to claim 1, wherein The starting the aluminum electrolysis cell includes: Lifting the anode cone, pouring liquid electrolyte into the aluminum electrolysis cell until the height of the liquid electrolyte in the aluminum electrolysis cell reaches a third preset height and the cell voltage of the aluminum electrolysis cell reaches a preset voltage, completing the start of the aluminum electrolysis cell.

8. The method according to claim 1, wherein The first preset height is 500 mm to 800 mm, and the second preset height is 400 mm to 600 mm.

9. The method according to claim 1, wherein The first preset temperature is 800 °C, and the second preset temperature is 900 °C.

10. The method according to claim 1, characterized in that, The shunt ratio of the current shunt is greater than or equal to 70%.

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