Aluminum electrolysis spent cathode carbon leaching equipment and process for recovering valuable components thereof

Abstract

This invention provides a leaching device for waste cathode carbon from aluminum electrolysis and a process for recovering valuable components, relating to the field of solid waste treatment technology. The device includes a base, a leaching tank, a drive mechanism, and a leaching mechanism. A top cover is installed on the top of the leaching tank. The drive mechanism includes a motor mounted on the upper surface of the top cover. A drive key is connected to the motor's output shaft via a keyway. A sleeve is slidably connected to the outer wall of the drive key, and a positioning bolt is threaded inside the sleeve. This solution, through an adjustable leaching mechanism, allows for flexible adjustment of the stirring radius and stirring area of ​​the leaching rack according to the specifications of the leaching tank, the material loading volume, the slurry concentration, and other actual working conditions. This achieves full-volume, dead-angle-free leaching coverage within the leaching tank, effectively breaking the passivation film on the surface of the waste cathode carbon particles, promoting thorough mixing, repeated rinsing, and efficient contact between the waste cathode carbon particles and the sodium hydroxide solution, and significantly improving the solid-liquid mass transfer rate.

Description

Technical Field

[0001] This invention relates to the field of solid waste treatment, and in particular to a carbon leaching device for aluminum electrolysis waste cathodes and a process for recovering valuable components. Background Technology

[0002] During the aluminum electrolysis production process, a large amount of waste cathode carbon is generated, which is a hazardous solid waste. Due to the continuous corrosion of the cathode carbon by the high-temperature electrolyte during production, the service life of most aluminum electrolysis cells is only 5-8 years. Realizing the resource utilization of hazardous waste is a key technological bottleneck for the green development of the aluminum industry.

[0003] In the past, waste cathode carbon was often directly landfilled, but the fluorides and cyanides in it could seep into the soil and pollute groundwater, causing significant impacts on the health of plants and animals and the ecological balance. Therefore, it was classified as hazardous solid waste. Currently, the treatment methods for waste cathode carbon include flotation, leaching with soluble aluminum salt solutions, high-temperature treatment, acid leaching, and alkaline leaching.

[0004] In the existing technology, traditional fixed-range leaching equipment has the defects of limited leaching area and unadjustable mixing intensity, which easily leads to insufficient contact between waste cathode carbon particles and sodium hydroxide solution. A dense reaction passivation film is easily formed on the surface of some waste cathode carbon particles, which hinders the continuous reaction.

[0005] Therefore, it is necessary to provide a carbon leaching device for aluminum electrolysis waste cathodes and a process for recovering valuable components to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a leaching device for waste cathode carbon from aluminum electrolysis and a process for recovering valuable components. It solves the problems of limited leaching area and unadjustable mixing intensity in fixed-range leaching devices in related technologies, which easily lead to insufficient contact between waste cathode carbon particles and sodium hydroxide solution.

[0007] To solve the above-mentioned technical problems, the present invention provides an aluminum electrolysis waste cathode carbon leaching device, including a base, a leaching tank, a drive mechanism and a leaching mechanism;

[0008] The leaching tank is equipped with a top cover. The driving mechanism includes a motor mounted on the upper surface of the top cover. The output shaft of the motor is connected to a drive keyway via a keyway. A sleeve is slidably connected to the outer wall of the drive keyway. A positioning bolt is threaded inside the sleeve. A drive gear is fixed at the bottom of the sleeve and inside the leaching tank.

[0009] The leaching mechanism includes a first rotating frame, with three adjusting gears rotatably connected to the bottom of the first rotating frame. A positioning seat is fixed to the inner wall of the leaching tank, and a second rotating frame is rotatably connected to the top of the positioning seat. A rotating shaft is rotatably connected to the center of the top cover and located at the center of the first rotating frame. A first gear and a second gear are fixed to the outer wall of the rotating shaft and located above and below the first rotating frame, respectively. A fixed gear is fixed to the upper surface of the first rotating frame and located at the bottom of the first gear. A rotating rod is rotatably connected to the center of the second gear. A leaching frame is fixed to the center of each of the three adjusting gears.

[0010] Preferably, a microwave digestion base is installed inside the base, the leaching tank is located inside the microwave digestion base, the positioning bolt passes through the inside of the sleeve and extends to the outer wall of the drive key rod, and the outer wall of the sleeve is slidably connected to the top cover through a lifting oil seal.

[0011] Preferably, the drive gear is adapted to the first gear and the fixed gear, and the rotating shaft passes through the axis of the first rotating frame and the fixed gear without contacting the first rotating frame and the fixed gear.

[0012] Preferably, the upper surface of the fixed gear and the lower surface of the first gear are in contact with each other, and the second gear and the three adjusting gears mesh with each other.

[0013] Preferably, the bottom end of the rotating rod is rotatably connected to the axis of the second rotating frame, and the bottom ends of the three leaching frames are rotatably connected to the second rotating frame.

[0014] Preferably, it also includes a scraping mechanism;

[0015] The scraping mechanism includes a positioning sleeve fixed to the bottom of the top cover and located inside the leaching tank. A positioning frame is rotatably connected to the outer wall of the positioning seat and located below the second rotating frame. A scraper is fixed to the outer wall of the positioning frame.

[0016] The scraper is slidably connected at the axis of the positioning sleeve above it, and the outer wall of the scraper is in contact with the inner wall of the leaching tank.

[0017] Preferably, it also includes an exhaust mechanism;

[0018] The exhaust mechanism includes an exhaust pipe fixed inside the top cover. A driven rod is rotatably connected inside the top cover and located on one side of the exhaust pipe. An exhaust gear is fixed at the bottom end of the driven rod. A protruding disc is fixed on the outer wall of the driven rod and located above the exhaust gear. A first connecting disc is fixed on the inner wall of the exhaust pipe. An exhaust key rod is slidably connected inside the first connecting disc. A second connecting disc is fixed on the outer wall of the exhaust key rod. A spring is fixed at the bottom of the second connecting disc. A sealing block and a guide wheel are respectively installed at the upper and lower ends of the exhaust key rod.

[0019] Preferably, the second connecting plate slides vertically about the exhaust pipe, the bottom of the spring is fixedly connected to the upper surface of the first connecting plate, the sealing block blocks the exhaust pipe outlet, the guide wheel and the raised plate are in contact with each other, and the exhaust gear and the fixed gear mesh with each other.

[0020] A process for recovering valuable components from waste cathode carbon in aluminum electrolysis includes the following steps:

[0021] S1: After crushing, grinding and sieving the aluminum electrolysis waste cathode carbon raw material to a certain mesh size, place it in a drying oven and dry it at a certain temperature for a period of time for later use.

[0022] S2: Weigh the dried waste cathode carbon and a certain concentration of sodium hydroxide solution, mix them according to a certain solid-liquid ratio, and place them in a microwave digestion device for leaching at a certain temperature for a period of time. After leaching, centrifuge to obtain alkaline leaching solution and alkaline leaching residue. Place the alkaline leaching residue in a drying oven and dry it at a certain temperature for a period of time for later use. Leaching needs to be carried out in a leaching tank.

[0023] S3: Weigh potassium sulfate and a certain concentration of concentrated sulfuric acid and add them to a beaker according to a certain solid-liquid ratio. Place the beaker in an ultrasonic water bath for a period of time to promote the thermal decomposition of K2SO4 to generate H2O2. After ultrasonic treatment, weigh the dried alkaline leaching residue according to a certain solid-liquid ratio and mix them. Place the mixture in a microwave digestion device and leach it at a certain temperature for a period of time to remove insoluble CaF2 and some residual impurities. After leaching, centrifuge to obtain acid leaching solution and acid leaching residue. Centrifuge and wash the acid leaching residue according to a certain solid-liquid ratio. Repeat the process three times. Collect and recover the waste liquid after washing. Place the material in a drying oven and dry it at a certain temperature for a period of time to obtain high-purity carbon blocks.

[0024] S4: Collect and mix the acid leaching solution and washing water produced in steps S2 and S3, and add calcium hydroxide to adjust the pH to 7-8. Place the mixture in a constant temperature water bath and react it at a certain temperature for a period of time. Separate the solid and liquid to obtain calcium fluoride and filtrate A.

[0025] S5: Add sodium hydroxide to filtrate A to adjust the pH to 10-11.5, place it in a constant temperature water bath and react for a period of time at a certain temperature. Separate the solid and liquid to obtain cryolite and filtrate B. Obtain sodium sulfate by evaporation and crystallization of filtrate B.

[0026] Compared with related technologies, the aluminum electrolysis waste cathode carbon leaching equipment and its process for recovering valuable components provided by the present invention have the following beneficial effects:

[0027] With an adjustable leaching range leaching mechanism, the stirring radius and stirring area of ​​the leaching rack can be flexibly adjusted according to the actual working conditions such as the specifications of the leaching tank, the material loading amount, and the slurry concentration. This achieves full-volume, dead-angle-free leaching coverage in the leaching tank, effectively breaking the passivation film on the surface of the waste cathode carbon particles, promoting full mixing, repeated rinsing, and efficient contact between the waste cathode carbon particles and the sodium hydroxide solution, and significantly improving the solid-liquid mass transfer rate. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on the structures shown in these drawings without creative effort.

[0029] Figure 1 The optimal structural schematic diagram provided for this invention;

[0030] Figure 2 for Figure 1 The diagram shows a cross-sectional view of the leaching tank and its top cover.

[0031] Figure 3 for Figure 2 The diagram shows a cross-sectional view of the drive mechanism.

[0032] Figure 4 for Figure 2 The diagram shows the structure of the leaching mechanism.

[0033] Figure 5 for Figure 4 The enlarged structural diagram at point A is shown below;

[0034] Figure 6 for Figure 4 The diagram shown is a top-down view of the structure.

[0035] Figure 7 for Figure 4 The diagram shows the leaching mechanism's rotation adjustment working state.

[0036] Figure 8 for Figure 7 The enlarged structural diagram at point B is shown below;

[0037] Figure 9 for Figure 7 The diagram shows the working state of the leaching mechanism controlled by the descent of the drive gear.

[0038] Figure 10 for Figure 9 The enlarged structural diagram at point C is shown below;

[0039] Figure 11 A schematic diagram showing the working state of the scraping mechanism triggered when the leaching mechanism is adjusted to its maximum range, as provided by the present invention.

[0040] Figure 12 A detailed structural diagram of the scraping mechanism provided by the present invention;

[0041] Figure 13 A detailed structural diagram of the exhaust mechanism provided by the present invention;

[0042] Figure 14 for Figure 13 The diagram shows an enlarged view of the structure at point D.

[0043] Figure 15 The flowchart of the process for recovering valuable components from waste cathode carbon in aluminum electrolysis provided by this invention.

[0044] Explanation of icon numbers:

[0045] 1. Base;

[0046] 2. Microwave digestion stand; 3. Leaching tank; 4. Top cover;

[0047] 5. Drive mechanism; 51. Motor; 52. Drive key; 53. Sleeve; 54. Drive gear; 55. Positioning bolt;

[0048] 6. Leaching mechanism; 61. First rotating frame; 62. Adjusting gear; 63. Positioning seat; 64. Second rotating frame; 65. Rotating shaft; 66. First gear; 67. Second gear; 68. Fixed gear; 69. Rotating rod; 610. Leaching frame.

[0049] 7. Scraping mechanism; 71. Positioning sleeve; 72. Scraper; 73. Positioning frame;

[0050] 8. Exhaust mechanism; 81. Exhaust pipe; 82. Driven rod; 83. Exhaust gear; 84. Raised disc; 85. First connecting disc; 86. Exhaust key rod; 87. Second connecting disc; 88. Spring; 89. Sealing block; 810. Guide wheel. Detailed Implementation

[0051] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those of ordinary skill in the art without creative effort are within the scope of protection of the present invention.

[0052] This invention provides a carbon leaching device for waste cathodes from aluminum electrolysis and a process for recovering valuable components.

[0053] First embodiment:

[0054] Please see Figures 1 to 10 A carbon leaching device for aluminum electrolysis waste cathodes includes a base 1, a leaching tank 3, a drive mechanism 5, and a leaching mechanism 6.

[0055] The top of the leaching tank 3 is equipped with a top cover 4. The drive mechanism 5 includes a motor 51 installed on the upper surface of the top cover 4. The output shaft of the motor 51 is connected to a drive key 52 via a keyway. A sleeve 53 is slidably connected to the outer wall of the drive key 52. ​​A positioning bolt 55 is threadedly connected inside the sleeve 53. A drive gear 54 is fixedly installed at the bottom end of the sleeve 53 and inside the leaching tank 3.

[0056] The leaching mechanism 6 includes a first rotating frame 61, with three adjusting gears 62 rotatably connected to the bottom of the first rotating frame 61. A positioning seat 63 is fixed to the inner wall of the leaching tank 3, and a second rotating frame 64 is rotatably connected to the top of the positioning seat 63. A rotating shaft 65 is rotatably connected to the axis of the top cover 4 and located at the axis of the first rotating frame 61. A first gear 66 and a second gear 67 are fixed to the outer wall of the rotating shaft 65 and located above and below the first rotating frame 61, respectively. A fixed gear 68 is fixed to the upper surface of the first rotating frame 61 and located at the bottom of the first gear 66. A rotating rod 69 is rotatably connected to the axis of the second gear 67. A leaching frame 610 is fixed to the axis of each of the three adjusting gears 62.

[0057] The microwave digestion base 2 is installed inside the base 1, the leaching tank 3 is located inside the microwave digestion base 2, the positioning bolt 55 passes through the inside of the sleeve 53 and extends to the outer wall of the drive key 52, and the outer wall of the sleeve 53 is slidably connected to the top cover 4 through a lifting oil seal.

[0058] The drive gear 54 is adapted to the first gear 66 and the fixed gear 68. The rotating shaft 65 passes through the axis of the first rotating frame 61 and the fixed gear 68 and does not contact the first rotating frame 61 and the fixed gear 68.

[0059] The upper surface of the fixed gear 68 and the lower surface of the first gear 66 are in contact with each other, and the second gear 67 and the three adjusting gears 62 mesh with each other.

[0060] The bottom end of the rotating rod 69 is rotatably connected to the axis of the second rotating frame 64, and the bottom ends of the three leaching frames 610 are rotatably connected to the second rotating frame 64.

[0061] Please see Figures 1 to 3The motor 51 is started to control the drive key 52 to rotate. When the drive key 52 rotates, it can drive the sleeve 53 to control the drive gear 54 to rotate inside the leaching tank 3. Then, during the operation, the user rotates the positioning bolt 55 to loosen it and separate it from the drive key 52. ​​Then, the sleeve 53 is slid along the vertical direction of the drive key 52 to control the drive gear 54 to move up and down. After the up and down adjustment is completed, the positioning bolt 55 can be rotated to lock the sleeve 53 and the drive key 52 in place.

[0062] Understandably, the floating oil seal connection design ensures the sealing of the leaching tank 3 during the lifting and lowering of the sleeve 53 on the top cover 4.

[0063] Please see Figure 7 and Figure 8 When the drive gear 54 rotates, it meshes with the first gear 66, which controls the rotation of the second gear 67 via the rotating shaft 65. When the second gear 67 rotates in both directions, it further meshes with the three adjusting gears 62. Therefore, the rotation of the three adjusting gears 62 in both directions controls the expansion and contraction of the leaching rack 610. When expanded, the leaching range inside the leaching tank 3 can be increased; when contracted, the leaching range inside the leaching tank 3 can be decreased.

[0064] Please see Figure 9 and Figure 10 After the leaching range is adjusted, the user slides the drive gear 54 down so that it meshes with the first gear 66 and the fixed gear 68 at the same time. When the drive gear 54 rotates, it synchronously drives the first gear 66 and the fixed gear 68 to rotate at the same time. The rotation of the fixed gear 68 drives the first rotating frame 61 to control the three adjusting gears 62 and the three leaching frames 610 to rotate as a whole, so that the waste cathode carbon and sodium hydroxide solution in the leaching tank 3 can be leached and stirred.

[0065] Please see Figures 4 to 6 When the drive gear 54 independently controls the rotation of the first gear 66, the rotating shaft 65 and the second gear 67, the fixed gear 68 cannot mesh with the drive gear 54. Therefore, the fixed gear 68 cannot rotate. Thus, during the range adjustment stage of the leaching rack 610, the first rotating rack 61 will remain in a fixed state.

[0066] Furthermore, the first gear 66 and the second gear 67 position the first rotating frame 61 and the fixed gear 68, and then fix them by the rotating rod 69, thus ensuring the installation stability of the first rotating frame 61 and the fixed gear 68.

[0067] Secondly, when the drive gear 54 meshes with the first gear 66 and the fixed gear 68, the first gear 66 and the fixed gear 68 rotate simultaneously, thus ensuring the rotation of the first rotating frame 61. The first rotating frame 61 controls the overall rotation of the leaching frame 610 in the fixed state. Furthermore, the leaching frame 610 is rotated and connected through the positioning seat 63, the second rotating frame 64, the rotating rod 69, and the leaching frame 610, thereby ensuring stability during the adjustment and rotation process. In actual use, the user can replace the motor 51 with a servo motor, which can accurately ensure the precise positioning and tooth adjustment of the first gear 66 and the fixed gear 68, and smoothly achieve meshing transmission.

[0068] Secondly, after the drive gear 54 meshes with the first gear 66 and the fixed gear 68, when rotating, the first gear 66, the fixed gear 68, the first rotating frame 61 and the second gear 67 will rotate along the same axis. Since the first rotating frame 61 drives the adjusting gear 62 to rotate, the rotation of the second gear 67 will not mesh with the driving gear 62 to rotate independently.

[0069] This embodiment:

[0070] The leaching mechanism 6 with adjustable leaching range can flexibly adjust the stirring radius and stirring area of ​​the leaching rack 610 according to the actual working conditions such as the specifications of the leaching tank 3, the material loading amount, and the slurry concentration, so as to achieve full-volume, dead-angle-free leaching coverage in the leaching tank 3, effectively break the passivation film on the surface of the waste cathode carbon particles, promote the full mixing, repeated rinsing and efficient contact of the waste cathode carbon particles and sodium hydroxide solution, and greatly improve the solid-liquid mass transfer rate.

[0071] Accelerate the leaching reaction rate of valuable components, significantly improve the utilization rate of waste cathode carbon resource recovery, and increase the yield and economic benefits of subsequent purification of valuable components;

[0072] By adjusting the stirring range of the leaching rack 610, the stirring intensity inside the leaching tank 3 can be specifically enhanced, so that the waste cathode carbon particles deposited at the bottom of the tank can be stirred up in time and reintegrated into the slurry system to participate in the reaction, effectively preventing material deposition and caking.

[0073] Second embodiment:

[0074] Please refer to Figure 2 , Figure 11 and Figure 12 It also includes a scraping mechanism 7;

[0075] The scraping mechanism 7 includes a positioning sleeve 71 fixed to the bottom of the top cover 4 and located inside the leaching tank 3. The positioning frame 73 is rotatably connected to the outer wall of the positioning seat 63 and located below the second rotating frame 64. A scraper 72 is fixed to the outer wall of the positioning frame 73.

[0076] The scraper 72 is slidably connected at the axis of the positioning sleeve 71 above it, and the outer wall of the scraper 72 is in contact with the inner wall of the leaching tank 3.

[0077] Please see Figure 11 When the adjusting gear 62 controls the leaching rack 610 to be adjusted to the maximum leaching range, the leaching rack 610 will come into contact with the scraper 72.

[0078] Please see Figure 2 and Figure 12 In the first embodiment, when the leaching rack 610 rotates to leach, the leaching rack 610 will contact the scraper 72 and rotate along the axis of the leaching tank 3. The rotation of the scraper 72 can rotate the inner wall of the leaching tank 3.

[0079] Please see Figure 12 Secondly, the scraper 72 rotates along the axis of the positioning sleeve 71. At the same time, the scraper 72 is rotatably connected to the positioning frame 73 and the positioning seat 63, thus ensuring the stability and smoothness of the scraper 72 during rotation.

[0080] This embodiment:

[0081] By automatically triggering the inner wall scraping function at the maximum leaching range, the scraper 72 can be precisely attached to the tank wall to scrape off the material attached to the tank wall in real time, so that the scraped material can be reintegrated into the slurry system inside the tank, fully contact and continuously react with the sodium hydroxide solution, and completely release the valuable components wrapped in the attached layer, thus avoiding resource waste.

[0082] At the same time, the scale layer can be scraped off in the early stage of its formation, preventing the scale layer from thickening and hardening, ensuring that the inner wall of the leaching tank 3 is smooth, ensuring that the maximum stirring range can achieve full volume coverage without dead corners in the tank, maintaining the uniform flow of the slurry, and keeping the temperature, alkali concentration, and material distribution in the tank consistent.

[0083] Third embodiment:

[0084] Please see Figure 1 , Figure 2 and Figure 10 It also includes an exhaust mechanism 8;

[0085] The exhaust mechanism 8 includes an exhaust pipe 81 fixed inside the top cover 4. A driven rod 82 is rotatably connected inside the top cover 4 and located on one side of the exhaust pipe 81. An exhaust gear 83 is fixed at the bottom end of the driven rod 82. A protruding disc 84 is fixed on the outer wall of the driven rod 82 and above the exhaust gear 83. A first connecting disc 85 is fixed on the inner wall of the exhaust pipe 81. An exhaust key rod 86 is slidably connected inside the first connecting disc 85. A second connecting disc 87 is fixed on the outer wall of the exhaust key rod 86. A spring 88 is fixed at the bottom of the second connecting disc 87. A sealing block 89 and a guide wheel 810 are respectively installed at the upper and lower ends of the exhaust key rod 86.

[0086] The second connecting plate 87 slides vertically about the exhaust pipe 81. The bottom of the spring 88 is fixedly connected to the upper surface of the first connecting plate 85. The sealing block 89 blocks the exhaust end of the exhaust pipe 81. The guide wheel 810 and the raised plate 84 are in contact with each other. The exhaust gear 83 and the fixed gear 68 mesh with each other.

[0087] Please see Figure 13 and Figure 14 In the first embodiment, during the rotation of the fixed gear 68, the meshing transmission exhaust gear 83 rotates. When the exhaust gear 83 rotates, it drives the raised disc 84 to rotate. When the raised end of the raised disc 84 rotates, the raised structure can control the guide wheel 810 to rise. The rise of the guide wheel 810 drives the exhaust key rod 86 and the second connecting disc 87 to rise. When rising, the spring 88 extends, and at the same time, the sealing block 89 rises, causing the exhaust pipe 81 to open. When it opens, the gas in the leaching tank 3 will be exhausted through the exhaust pipe 81. When the raised shape of the raised disc 84 moves away from the guide wheel 810, the sealing block 89 automatically resets to seal the exhaust pipe 81, thus realizing the intermittent exhaust function.

[0088] This embodiment:

[0089] During the leaching process, the residual aluminum, aluminum carbide and other components in the waste cathode carbon will react with the sodium hydroxide solution to produce gases such as hydrogen. If the gas continues to accumulate in the leaching tank 3, it will cause the pressure inside the tank to rise abnormally, which poses a safety hazard.

[0090] Intermittent venting allows gas to be released in time when it accumulates to a certain level, maintaining the pressure inside the tank within a safe and stable process range, avoiding equipment risks caused by sudden pressure increases, and significantly improving the operational safety of the water immersion process.

[0091] Secondly, intermittent venting can periodically disrupt the gas film, allowing the gas inside the slurry to escape in time, enabling the alkali solution to more fully wet and wash the surface of the material, accelerating the dissolution and reaction rate of electrolyte components, and further improving the leaching rate and recovery effect of valuable components.

[0092] A process for recovering valuable components from waste cathode carbon in aluminum electrolysis includes the following steps:

[0093] S1: After crushing, grinding and sieving the aluminum electrolysis waste cathode carbon raw material to a certain mesh size, place it in a drying oven and dry it at a certain temperature for a period of time for later use.

[0094] S2: Weigh the dried waste cathode carbon and a certain concentration of sodium hydroxide solution, mix them according to a certain solid-liquid ratio, and place them in a microwave digestion device for leaching at a certain temperature for a period of time. After leaching, centrifuge to obtain alkaline leaching solution and alkaline leaching residue. Place the alkaline leaching residue in a drying oven and dry it at a certain temperature for a period of time for later use. Leaching treatment is required in leaching tank 3.

[0095] S3: Weigh potassium sulfate and a certain concentration of concentrated sulfuric acid and add them to a beaker according to a certain solid-liquid ratio. Place the beaker in an ultrasonic water bath for a period of time to promote the thermal decomposition of K2SO4 to generate H2O2. After ultrasonic treatment, weigh the dried alkaline leaching residue according to a certain solid-liquid ratio and mix them. Place the mixture in a microwave digestion device and leach it at a certain temperature for a period of time to remove insoluble CaF2 and some residual impurities. After leaching, centrifuge to obtain acid leaching solution and acid leaching residue. Centrifuge and wash the acid leaching residue according to a certain solid-liquid ratio. Repeat the process three times. Collect and recover the waste liquid after washing. Place the material in a drying oven and dry it at a certain temperature for a period of time to obtain high-purity carbon blocks.

[0096] S4: Collect and mix the acid leaching solution and washing water produced in steps S2 and S3, and add calcium hydroxide to adjust the pH to 7-8. Place the mixture in a constant temperature water bath and react it at a certain temperature for a period of time. Separate the solid and liquid to obtain calcium fluoride and filtrate A.

[0097] S5: Add sodium hydroxide to filtrate A to adjust the pH to 10-11.5, place it in a constant temperature water bath and react for a period of time at a certain temperature. Separate the solid and liquid to obtain cryolite and filtrate B. Obtain sodium sulfate by evaporation and crystallization of filtrate B.

[0098] This process:

[0099] The process for recovering valuable components from waste cathode carbon in aluminum electrolysis through microwave hydrothermal assisted leaching employs a two-step process (microwave hydrothermal alkaline leaching pretreatment combined with microwave hydrothermal sulfuric acid leaching) and incorporates an oxidation intercalation mechanism. This process achieves efficient removal of insoluble CaF2 and recovery of valuable components from the waste cathode carbon. This method has advantages such as short reaction time, low energy consumption, and environmental friendliness, providing an innovative solution for the resource utilization of hazardous waste from aluminum electrolysis.

[0100] To achieve the triple goals of harmless treatment, resource utilization, and high-value utilization of hazardous solid waste, while also meeting the requirements of dual-carbon and industrial synergy development, and realizing the circular economy goal of replacing primary resources with solid waste resources.

[0101] Please refer to the reference again. Figures 1 to 15The working principle of the aluminum electrolysis waste cathode carbon leaching equipment and its valuable component recovery process provided by the present invention is as follows:

[0102] Step S1: Start the motor 51 to control the drive key 52 to rotate. When the drive key 52 rotates, it can drive the sleeve 53 to control the drive gear 54 to rotate in the leaching tank 3. Then, during the operation, the user rotates the positioning bolt 55 to loosen it and separate it from the drive key 52. ​​Then, slide the sleeve 53 along the vertical direction of the drive key 52 to control the drive gear 54 to move up and down. After the up and down adjustment is completed, the positioning bolt 55 can be rotated to lock the sleeve 53 and the drive key 52 in place.

[0103] Step S2: When the drive gear 54 rotates, it engages the first gear 66 to control the rotation of the second gear 67 via the rotating shaft 65. When the second gear 67 rotates forward and backward, it further engages the three adjusting gears 62 to rotate. Therefore, the forward and reverse rotation of the three adjusting gears 62 controls the expansion and contraction of the leaching rack 610. When expanded, the leaching range in the leaching tank 3 can be increased; when contracted, the leaching range in the leaching tank 3 can be decreased.

[0104] After the leaching range is adjusted, the user slides the drive gear 54 downwards so that it meshes with the first gear 66 and the fixed gear 68 simultaneously. When the drive gear 54 rotates, it synchronously drives the first gear 66 and the fixed gear 68 to rotate at the same time. The rotation of the fixed gear 68 drives the first rotating frame 61 to control the three adjusting gears 62 and the three leaching frames 610 to rotate as a whole, so that the waste cathode carbon and sodium hydroxide solution in the leaching tank 3 can be leached and stirred. During the leaching process, the microwave digestion seat 2 can perform microwave digestion inside the leaching tank 3.

[0105] The above description is only a preferred embodiment of the present invention and does not limit the patent scope of the present invention. All equivalent structural transformations made under the concept of the present invention using the contents of the present invention specification and drawings, or direct / indirect applications in other related technical fields, are included within the patent protection scope of the present invention.

Claims

1. A carbon leaching device for waste cathodes from aluminum electrolysis, characterized in that, Includes a base, leaching tank, drive mechanism, and leaching mechanism; The leaching tank is equipped with a top cover. The driving mechanism includes a motor mounted on the upper surface of the top cover. The output shaft of the motor is connected to a drive keyway via a keyway. A sleeve is slidably connected to the outer wall of the drive keyway. A positioning bolt is threaded inside the sleeve. A drive gear is fixed at the bottom of the sleeve and inside the leaching tank. The leaching mechanism includes a first rotating frame, with three adjusting gears rotatably connected to the bottom of the first rotating frame. A positioning seat is fixed to the inner wall of the leaching tank, and a second rotating frame is rotatably connected to the top of the positioning seat. A rotating shaft is rotatably connected to the center of the top cover and located at the center of the first rotating frame. A first gear and a second gear are fixed to the outer wall of the rotating shaft and located above and below the first rotating frame, respectively. A fixed gear is fixed to the upper surface of the first rotating frame and located at the bottom of the first gear. A rotating rod is rotatably connected to the center of the second gear. A leaching frame is fixed to the center of each of the three adjusting gears.

2. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, The base is equipped with a microwave digestion stand, the leaching tank is located inside the microwave digestion stand, the positioning bolt passes through the inside of the sleeve and extends to the outer wall of the drive key rod, and the outer wall of the sleeve is slidably connected to the top cover through a lifting oil seal.

3. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, The drive gear, the first gear, and the fixed gear are adapted to each other, and the rotating shaft passes through the axis of the first rotating frame and the fixed gear without contacting the first rotating frame and the fixed gear.

4. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, The upper surface of the fixed gear and the lower surface of the first gear are in contact with each other, and the second gear and the three adjusting gears mesh with each other.

5. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, The bottom end of the rotating rod is rotatably connected to the axis of the second rotating frame, and the bottom ends of the three leaching frames are rotatably connected to the second rotating frame.

6. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, It also includes a scraping mechanism; The scraping mechanism includes a positioning sleeve fixed to the bottom of the top cover and located inside the leaching tank. A positioning frame is rotatably connected to the outer wall of the positioning seat and located below the second rotating frame. A scraper is fixed to the outer wall of the positioning frame. The scraper is slidably connected at the axis of the positioning sleeve above it, and the outer wall of the scraper is in contact with the inner wall of the leaching tank.

7. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 1, characterized in that, It also includes the exhaust system; The exhaust mechanism includes an exhaust pipe fixed inside the top cover. A driven rod is rotatably connected inside the top cover and located on one side of the exhaust pipe. An exhaust gear is fixed at the bottom end of the driven rod. A protruding disc is fixed on the outer wall of the driven rod and located above the exhaust gear. A first connecting disc is fixed on the inner wall of the exhaust pipe. An exhaust key rod is slidably connected inside the first connecting disc. A second connecting disc is fixed on the outer wall of the exhaust key rod. A spring is fixed at the bottom of the second connecting disc. A sealing block and a guide wheel are respectively installed at the upper and lower ends of the exhaust key rod.

8. The aluminum electrolysis waste cathode carbon leaching equipment according to claim 7, characterized in that, The second connecting plate slides vertically relative to the exhaust pipe. The bottom of the spring is fixedly connected to the upper surface of the first connecting plate. The sealing block blocks the exhaust pipe outlet. The guide wheel and the raised plate are in contact with each other. The exhaust gear and the fixed gear mesh with each other.

9. A process for recovering valuable components from waste cathode carbon in aluminum electrolysis, characterized in that, The process for recovering valuable components from waste cathode carbon in aluminum electrolysis includes a leaching device for waste cathode carbon in aluminum electrolysis as described in any one of claims 1-8, comprising the following steps: S1: After crushing, grinding and sieving the aluminum electrolysis waste cathode carbon raw material to a certain mesh size, place it in a drying oven and dry it at a certain temperature for a period of time for later use. S2: Weigh the dried waste cathode carbon and a certain concentration of sodium hydroxide solution, mix them according to a certain solid-liquid ratio, and place them in a microwave digestion device for leaching at a certain temperature for a period of time. After leaching, centrifuge to obtain alkaline leaching solution and alkaline leaching residue. Place the alkaline leaching residue in a drying oven and dry it at a certain temperature for a period of time for later use. Leaching needs to be carried out in a leaching tank. S3: Weigh potassium sulfate and a certain concentration of concentrated sulfuric acid and add them to a beaker according to a certain solid-liquid ratio. Place the beaker in an ultrasonic water bath for a period of time to promote the thermal decomposition of K2SO4 to generate H2O2. After ultrasonic treatment, weigh the dried alkaline leaching residue according to a certain solid-liquid ratio and mix them. Place the mixture in a microwave digestion device and leach it at a certain temperature for a period of time to remove insoluble CaF2 and some residual impurities. After leaching, centrifuge to obtain acid leaching solution and acid leaching residue. Centrifuge and wash the acid leaching residue according to a certain solid-liquid ratio. Repeat the process three times. Collect and recover the waste liquid after washing. Place the material in a drying oven and dry it at a certain temperature for a period of time to obtain high-purity carbon blocks. S4: Collect and mix the acid leaching solution and washing water produced in steps S2 and S3, and add calcium hydroxide to adjust the pH to 7-8. Place the mixture in a constant temperature water bath and react it at a certain temperature for a period of time. Separate the solid and liquid to obtain calcium fluoride and filtrate A. S5: Add sodium hydroxide to filtrate A to adjust the pH to 10-11.5, place it in a constant temperature water bath and react for a period of time at a certain temperature. Separate the solid and liquid to obtain cryolite and filtrate B. Obtain sodium sulfate by evaporation and crystallization of filtrate B.

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