Method for purifying carbon from waste cathode carbon block

Abstract

The invention provides a method for purifying carbon from a waste cathode carbon block, and relates to the technical field of carbon recovery and purification. The invention discloses a method for purifying carbon from a waste cathode carbon block. The method comprises the following steps: S1, pretreating raw materials; s2, roasting treatment is conducted, specifically, a cathode carbon block and sodium carbonate are weighed, mixed and then subjected to ball milling, the mixture is placed in a muffle furnace to be roasted, and a roasted material is obtained; gas volatilized in the roasting process is oxidized through a hypochlorous acid solution and collected; and S3, purifying the carbon block, cooling the roasted material, carrying out water immersion treatment with pure water, carrying out solid-liquid separation to obtain a filter residue A and a filtrate A, carrying out water washing treatment on the filter residue A at normal temperature, and carrying out water washing and drying treatment to obtain the high-purity carbon block. According to the method, toxic substances in the cathode carbon block can be efficiently decomposed, the harm of the toxic substances to the environment is greatly reduced, high-purity graphite carbon, cryolite, sodium carbonate, sodium fluoride and other substances with important economic values are successfully recycled, and remarkable environmental and economic benefits are shown.

Description

Technical Field

[0001] This invention relates to the field of carbon recycling and purification technology, and more particularly to a method for purifying carbon from waste cathode carbon blocks. Background Technology

[0002] Waste aluminum electrolysis cathode carbon blocks are a type of hazardous solid waste generated in the aluminum electrolysis industry. They contain large amounts of fluorides (such as NaF, Na3AlF6 and CaF2), cyanides (such as NaCN, Na3Fe(CN)6 and Na4Fe(CN)6) and carbon materials (such as graphite and anthracite).

[0003] The direct emission of these substances not only poses a serious pollution risk to the environment but also threatens human health. However, the cathode carbon blocks contain high levels of fluorides and carbon, making them valuable for recycling. Further research is needed to determine how to effectively extract and purify the carbon within them.

[0004] Therefore, it is necessary to provide a method for purifying carbon from waste cathode carbon blocks to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for purifying carbon from waste cathode carbon blocks, solving the problem in related technologies where the effective extraction and purification of carbon requires further research.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for purifying carbon from waste cathode carbon blocks, comprising the following steps:

[0007] Step S1, raw material pretreatment: After the cathode carbon blocks are fully crushed and screened, the screened cathode carbon blocks are put into the carbon powder drying equipment for drying to obtain dried material.

[0008] Step S2, calcination treatment: weigh the cathode carbon block and sodium carbonate, mix them and ball mill them, then place the mixture in a muffle furnace for calcination to obtain calcined material; the gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected.

[0009] Step S3: Purification of carbon blocks. After the calcined material is cooled, it is treated with pure water immersion and solid-liquid separation to obtain filter residue A and filtrate A. Filter residue A is washed with water at room temperature. After washing and drying, high-purity carbon blocks are obtained.

[0010] Preferably, in step S1, a crushing device is used for the crushing process; and in the screening process, the crushed carbon blocks are passed through a 100-200 mesh sieve using a screening device.

[0011] Preferably, in step S2, the cathode carbon block and sodium carbonate are placed in a planetary ball mill and ball-milled for 15 minutes at a mass ratio of 1 to 1.33:1.

[0012] Preferably, the roasting temperature in the muffle furnace is 850°C and the roasting time is 3 hours.

[0013] Preferably, in step S3, the calcined material is placed in a polytetrafluoroethylene beaker and soaked in water at a liquid-to-solid ratio of 5 to 7:1. The mixture is then kept at 60°C in a water bath and stirred at 300 rpm for 3 hours.

[0014] Preferably, the water washing process in step S3 is performed with a liquid-to-solid ratio of 4:1.

[0015] Preferably, the method further includes the following steps:

[0016] Step S4: Place filtrate A in a constant temperature water bath and stir. During the stirring process, introduce the gas collected in step S2 and add sodium hydroxide to adjust the pH to 9-11.5. React and filter to obtain cryolite and filtrate B.

[0017] In step S5, the filtrate B is evaporated and crystallized, and the crystallized product is selectively filtered to obtain sodium carbonate and sodium fluoride.

[0018] Preferably, in step S4, the constant temperature water bath is stirred at a temperature of 60°C.

[0019] Preferably, in step S5, selective filtration utilizes filter materials with different pore sizes to selectively filter the crystallized product sequentially, resulting in sodium carbonate with a particle size <50μm and sodium fluoride with a particle size >100μm.

[0020] Compared with related technologies, the method for purifying carbon from waste cathode carbon blocks provided by the present invention has the following beneficial effects:

[0021] It cleverly combines the advantages of pyrometallurgy and hydrometallurgy, featuring simple process, high reaction efficiency and high product purity. It can not only achieve efficient decomposition of toxic substances in cathode carbon blocks, greatly reducing their harm to the environment, but also successfully recover high-purity graphite carbon, cryolite, sodium carbonate and sodium fluoride and other substances with important economic value, demonstrating significant environmental and economic benefits. Attached Figure Description

[0022] 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.

[0023] Figure 1 A system flow diagram of the method for purifying carbon from waste cathode carbon blocks provided by the present invention;

[0024] Figure 2 A three-dimensional view of the first embodiment of the charcoal powder drying equipment provided by the present invention;

[0025] Figure 3 for Figure 2 Left view of the AA cross-sectional structure shown;

[0026] Figure 4 for Figure 3 The exploded 3D view of the shielding ring connection section shown;

[0027] Figure 5 for Figure 3 A schematic diagram of the cross-sectional structure of the drying tube shown;

[0028] Figure 6 for Figure 4 A top view showing the drying tube aligned with the shielding ring.

[0029] Figure 7 A schematic diagram illustrating the principle of charcoal powder entering the drying tube in the first embodiment of the charcoal powder drying equipment provided by the present invention, wherein... Figure 7 (a) in the diagram shows the initial feeding state when the material is being fed from the bottom of the pipe. Figure 7 (b) in the diagram shows the state of material feeding from the bottom of the pipe to the middle section. Figure 7 (c) in the diagram shows the state of feeding material from the bottom of the pipe to the middle section;

[0030] Figure 8 A three-dimensional view of a second embodiment of the charcoal powder drying equipment provided by the present invention;

[0031] Figure 9 for Figure 8 Left view of the BB cross-sectional structure shown;

[0032] Figure 10 for Figure 8 The top view of the whole is shown.

[0033] Explanation of icon numbers:

[0034] 100. Heat exchange chamber; 200. Exhaust chamber; 300. Feeding chamber;

[0035] 1. Drying tank body; 11. Feed inlet; 12. Discharge outlet; 13. First exhaust pipe; 14. Air inlet pipe; 15. Second exhaust pipe;

[0036] 2. Driving components;

[0037] 3. Rotating disk;

[0038] 4. Drying tube; 41. Tube body; 42. Isolation filter;

[0039] 5. Shielding ring;

[0040] 6. Connecting pipe;

[0041] 7. Spoiler assembly; 71. Support plate; 72. Spoiler shaft; 73. Transmission component.

[0042] The realization of the objective, functional features and advantages of the present invention will be further explained in conjunction with the embodiments and with reference to the accompanying drawings. Detailed Implementation

[0043] 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.

[0044] This invention provides a method for purifying carbon from waste cathode carbon blocks.

[0045] Please see Figure 1 The method for purifying carbon from waste cathode carbon blocks in this invention includes the following steps:

[0046] Step S1, raw material pretreatment: After the cathode carbon blocks are fully crushed and screened, the screened cathode carbon blocks are put into the carbon powder drying equipment for drying to obtain dried material.

[0047] Step S2, calcination treatment: weigh the cathode carbon block and sodium carbonate, mix them and ball mill them, then place the mixture in a muffle furnace for calcination to obtain calcined material; the gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected.

[0048] Step S3: Purification of carbon blocks. After the calcined material is cooled, it is treated with pure water immersion and solid-liquid separation to obtain filter residue A and filtrate A. Filter residue A is washed with water at room temperature. After washing and drying, high-purity carbon blocks are obtained.

[0049] Specifically, in step S1, crushing equipment is used for crushing; during screening, the crushed carbon blocks are sieved through a 100-200 mesh sieve using a screening device.

[0050] Specifically, in step S2, the cathode carbon block and sodium carbonate are placed in a planetary ball mill at a mass ratio of 1 to 1.33:1 and ball-milled for 15 minutes.

[0051] Specifically, the roasting temperature in the muffle furnace is 850°C, and the roasting time is 3 hours.

[0052] Specifically, in step S3, the calcined material is placed in a polytetrafluoroethylene beaker and soaked in water at a liquid-to-solid ratio of 5 to 7:1. The mixture is then kept at 60°C in a water bath and stirred at 300 rpm for 3 hours.

[0053] Specifically, in step S3, the water washing process is performed with a liquid-to-solid ratio of 4:1.

[0054] The method for purifying carbon from waste cathode carbon blocks further includes the following steps:

[0055] Step S4: Place filtrate A in a constant temperature water bath and stir. During the stirring process, introduce the gas collected in step S2 and add sodium hydroxide to adjust the pH to 9-11.5. React and filter to obtain cryolite and filtrate B.

[0056] In step S5, the filtrate B is evaporated and crystallized, and the crystallized product is selectively filtered to obtain sodium carbonate and sodium fluoride.

[0057] Specifically, in step S4, the constant temperature water bath is stirred at a temperature of 60°C.

[0058] Specifically, in step S5, selective filtration utilizes filter materials with different pore sizes to selectively filter the crystallized product sequentially, resulting in sodium carbonate with a particle size <50μm and sodium fluoride with a particle size >100μm.

[0059] Beneficial effects:

[0060] It cleverly combines the advantages of pyrometallurgy and hydrometallurgy, and has outstanding features such as simple process, high reaction efficiency and high product purity. It can not only achieve efficient decomposition of toxic substances in cathode carbon blocks, greatly reducing their harm to the environment, but also successfully recover high-purity graphite carbon, cryolite, sodium carbonate and sodium fluoride and other substances with important economic value, demonstrating significant environmental and economic benefits.

[0061] Implementation Case 1:

[0062] Step S1: Place the cathode carbon block in a professional crushing device for thorough crushing, then pass the crushed carbon block through a 150-mesh sieve using a screening device. Place the screened cathode carbon block into a carbon powder drying device to remove excess moisture and ensure that the cathode carbon block reaches a dry state suitable for subsequent processing.

[0063] Step S2: Weigh 50g of dried cathode carbon block and sodium carbonate, put them into a planetary ball mill at a mass ratio of 1:1 and ball mill for 15min to fully mix the cathode carbon block and sodium carbonate. Place the mixture in a crucible and place it in a muffle furnace to calcine at 850℃ for 3h to achieve effective conversion of fluoride and decomposition of cyanide. The gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected.

[0064] Step S3: After the calcined product is cooled, it is placed in a polytetrafluoroethylene beaker and soaked in pure water at a liquid-to-solid ratio of 5:1. The mixture is then reacted in a water bath at 60°C with stirring at 300 rpm for 3 hours. After solid-liquid separation, filter residue A and filtrate A are obtained. Filter residue A is washed with water at a liquid-to-solid ratio of 4:1 at room temperature. After washing and drying, high-purity carbon blocks are obtained.

[0065] Step S4: Place filtrate A in a constant temperature water bath and stir at 60°C. During the stirring process, introduce the gas collected in step S2. At the same time, add sodium hydroxide as appropriate to adjust the pH to 9.5. After reacting for a period of time, filter to obtain cryolite and filtrate B.

[0066] Step S5: Evaporate and crystallize the filtrate B. Use filter materials with different pore sizes to selectively filter the crystallized products to obtain sodium carbonate (particle size <50μm) and sodium fluoride (particle size >100μm).

[0067] Implementation Case 2:

[0068] Step S1: Place the cathode carbon block in a professional crushing device for thorough crushing, then pass the crushed carbon block through a 200-mesh sieve using a screening device. Place the screened cathode carbon block into a carbon powder drying device to remove excess moisture and ensure that the cathode carbon block reaches a dry state suitable for subsequent processing.

[0069] Step S2: Weigh 100g of dried cathode carbon block and sodium carbonate, put them into a planetary ball mill at a mass ratio of 4:3 and ball mill for 10 minutes to fully mix the cathode carbon block and sodium carbonate. Place the mixture in a crucible and place it in a muffle furnace to calcine at 950℃ for 4 hours to achieve effective conversion of fluoride and decomposition of cyanide. The gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected.

[0070] Step S3: After the calcined product is cooled, it is placed in a polytetrafluoroethylene beaker and soaked in pure water at a liquid-to-solid ratio of 6:1. The mixture is then reacted in a water bath at 70°C with stirring at 350 rpm for 5 hours. After solid-liquid separation, filter residue A and filtrate A are obtained. Filter residue A is washed with water at a liquid-to-solid ratio of 5:1 at room temperature. After washing and drying, high-purity carbon blocks are obtained.

[0071] Step S4: Place filtrate A in a constant temperature water bath and stir at 70°C. During the stirring process, introduce the gas collected in step S2. At the same time, add sodium hydroxide as appropriate to adjust the pH to 10. After reacting for a period of time, filter to obtain cryolite and filtrate B.

[0072] Step S5: Evaporate and crystallize the filtrate B. Use filter materials with different pore sizes to selectively filter the crystallized products to obtain sodium carbonate (particle size <50μm) and sodium fluoride (particle size >100μm).

[0073] Implementation Case 3:

[0074] Step S1: Place the cathode carbon block in a professional crushing device for thorough crushing, then pass the crushed carbon block through a 100-mesh sieve using a screening device. Place the screened cathode carbon block into a carbon powder drying device to remove excess moisture and ensure that the cathode carbon block reaches a dry state suitable for subsequent processing.

[0075] Step S2: Weigh 250g of dried cathode carbon block and sodium carbonate, put them into a planetary ball mill at a mass ratio of 5:4 and ball mill for 20 minutes to fully mix the cathode carbon block and sodium carbonate. Place the mixture in a crucible and place it in a muffle furnace to calcine at 1000℃ for 5 hours to achieve effective conversion of fluoride and decomposition of cyanide. The gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected.

[0076] Step S3: After the calcined product is cooled, it is placed in a polytetrafluoroethylene beaker and soaked in pure water at a liquid-to-solid ratio of 7:1. The mixture is then reacted in a water bath at 80°C with stirring at 350 rpm for 3 hours. After solid-liquid separation, filter residue A and filtrate A are obtained. Filter residue A is washed with water at a liquid-to-solid ratio of 6:1 at room temperature. After washing and drying, high-purity carbon blocks are obtained.

[0077] Step S4: Place filtrate A in a constant temperature water bath and stir at 80°C. During the stirring process, introduce the gas collected in step S2. At the same time, add sodium hydroxide as appropriate to adjust the pH to 11. After reacting for a period of time, filter to obtain cryolite and filtrate B.

[0078] Step S5: Evaporate and crystallize the filtrate B. Use filter materials with different pore sizes to selectively filter the crystallized products to obtain sodium carbonate (particle size <50μm) and sodium fluoride (particle size >100μm).

[0079] The present invention also provides a carbon powder drying device for drying the cathode carbon blocks in the method for purifying carbon from waste cathode carbon blocks.

[0080] The data and analysis from the examples show that the recovery effect of the molten salt-assisted roasting method for recovering cathode carbon blocks in this invention is significantly affected by core parameters such as mass ratio, liquid-solid ratio, reaction temperature and time. Precise control of these parameters is the key to improving the recovery rate.

[0081] In practical industrial applications, the composition and impurity content of cathode carbon blocks vary from aluminum plant to plant, and reaction conditions need to be flexibly adjusted according to raw material analysis and recovery requirements.

[0082] This technical solution utilizes a Na2CO3 molten salt system to convert fluorides in the cathode carbon block into water-soluble NaF. The pH is adjusted and cryolite is recovered by using CO2 released during roasting, followed by stepwise crystallization to obtain NaF and Na2CO3.

[0083] This method has advantages such as high efficiency in detoxification, high resource recovery rate, and waste gas recycling, and is suitable for the green resource utilization of waste cathode carbon blocks from aluminum electrolysis.

[0084] First embodiment:

[0085] Please refer to the following: Figures 2 to 4 In this invention, the charcoal powder drying equipment includes:

[0086] The drying tank 1 is provided with a feed inlet 11, a discharge outlet 12, an air inlet pipe 14, a first exhaust pipe 13, and a second exhaust pipe 15.

[0087] The driving component 2 has a fixing part fixed to the top of the drying tank 1;

[0088] Two rotating disks 3 are rotatably installed inside the drying tank 1. A heat exchange chamber 100, an exhaust chamber 200, and a feeding chamber 300 are formed around the two rotating disks 3 and the drying tank 1. The output end of the feed inlet 11 passes through the exhaust chamber 200 and slides to seal with the top of the rotating disk 3. The discharge port 12 is connected to the feeding chamber 300. The air inlet pipe 14 is connected to the first exhaust pipe 13 through the heat exchange chamber 100. The second exhaust pipe 15 is connected to the exhaust chamber 200.

[0089] Eight drying tubes 4 are respectively installed through the two rotating disks 3. The output end of the feed inlet 11 is aligned with the rotation range of the input end of the drying tube 4. The drying tube 4 passes through the ventilation range of the heat exchange chamber 100.

[0090] A shielding ring 5 is fixed inside the drying tank 1, and the top of the shielding ring 5 is slidably sealed to the rotating disk 3.

[0091] When the bottom of the drying tube 4 is aligned with the top of the shielding ring 5, the output end of the drying tube 4 is closed; when the bottom of the drying tube 4 is separated from the shielding ring 5, the output end of the drying tube 4 is opened.

[0092] In this embodiment, the driving component 2 can be a motor structure, used to directly drive the rotating disk 3 to rotate stably inside the drying tank 1, so as to facilitate the switching of the use state of the drying tube 4.

[0093] In this embodiment, the drying tube 4 includes three usage states:

[0094] In the receiving state, the top of the drying tube 4 is aligned and connected with the output end of the feed inlet 11, the bottom of the drying tube 4 abuts against the top of the shielding ring 5, and the bottom of the drying tube 4 is closed, so that the material can enter the interior of the drying tube 4 through the feed inlet 11.

[0095] In the dry state, the top of the drying tube 4 is connected to the exhaust chamber 200, the bottom of the drying tube 4 abuts against the top of the shielding ring 5, and the bottom of the drying tube 4 is closed, which facilitates the stable rotation and adjustment of the drying tube 4 containing the material within the heat exchange chamber 100, and at the same time facilitates the heat exchange between the drying tube 4 and the heat exchange gas within the heat exchange chamber 100, which facilitates the drying of the material in the drying tube 4;

[0096] In the discharge state, the top of the drying pipe 4 is connected to the exhaust chamber 200, the bottom of the drying pipe 4 is staggered with the shielding ring 5, and the bottom of the drying pipe 4 is open to facilitate the downward discharge of the dried material in the drying pipe 4 into the range of the discharge chamber 300, and then downward discharge through the discharge port 12.

[0097] When the drying tube 4 is in the receiving state, the material is put into the interior of the drying tube 4 through the feed port 11, so that the material is stored inside the drying tube 4;

[0098] Start the drive unit 2, which drives the rotating disk 3 to rotate. The rotating disk 3 drives the eight drying tubes 4 to rotate synchronously, so that the drying tubes 4 filled with material switch from receiving state to drying state, and the drying tubes 4 in the discharge state switch to receiving state, so as to facilitate continuous material receiving and continuous drying of the material in the drying tubes 4.

[0099] During drying, the roasting exhaust gas is transmitted to the interior of the heat exchange chamber 100 through the air inlet pipe 14. The roasting exhaust gas is used to heat the drying tube 4, and the material stored in the drying tube 4 is heated and dried at the same time. This facilitates the heat exchange and drying of the material in the drying tube 4 by utilizing the roasting exhaust gas.

[0100] In this embodiment, the input end of the air inlet pipe 14 is provided with an air inlet device for conveying the roasting exhaust gas (gas temperature > 100°C) into the interior of the air inlet pipe 14. The roasting exhaust gas is produced in the muffle furnace.

[0101] In this embodiment, an air pump is provided in the output direction of the second exhaust pipe 15 to slowly extract the exhaust gas entering the exhaust chamber 200, so as to ensure the stable upward conveying of the air generated after drying without affecting the normal feeding of materials.

[0102] Please refer to the following: Figure 3 , Figure 4 and Figure 5 The drying tube 4 includes a tube body 41 and an isolation filter 42. The tube body 41 is fixedly connected to the two rotating disks 3, and the isolation filter 42 is fixed inside the tube body 41.

[0103] In this embodiment, the top of the isolation filter 42 has a conical structure, which is used to block materials from entering the interior of the isolation filter 42 and allows air to pass through both sides of the isolation filter 42.

[0104] In this embodiment, the tube body 41 is made of stainless steel thermally conductive material for heat exchange of the heat exchange gas, and after heat exchange, it is used to perform thermal drying treatment on the material between the tube body 41 and the isolation filter screen 42.

[0105] The isolation filter 42 facilitates the even spreading of materials entering the tube 41 on the inner wall of the tube 41, allowing the materials to fully exchange heat with the heat exchange gas through the tube 41, thereby improving the adequacy and efficiency of heat exchange drying.

[0106] When the drying tube 4 is in the drying state and the discharge state, the gas generated after heat exchange passes through the isolation filter 42 and is transported upward from the middle of the isolation filter 42 into the range of the exhaust chamber 200.

[0107] The working principle of the charcoal powder drying equipment provided in this embodiment is as follows:

[0108] It can be defined that the input end of the intake pipe 14 is continuously supplied with roasting exhaust gas, and the second exhaust pipe 15 continuously and slowly draws gas outward.

[0109] A1, Material input, such as Figure 7 As shown, when the drying tube 4 is in the receiving state, the material put into the inlet 11 is conveyed downward. The material passes through the top of the tube 41 and enters between the tube 41 and the isolation filter 42. Since the bottom of the tube 41 is kept closed, the material will be evenly spread on the inner wall of the tube 41, so that the material and the tube 41 are in full contact. At the same time, the middle of the isolation filter 42 has a ventilation gap for the dried gas.

[0110] A2, workstation switching, start the drive unit 2, the drive unit 2 drives the rotating disk 3 to rotate clockwise, the rotating disk 3 drives the eight drying tubes 4 to rotate synchronously as a whole, the drying tubes 4 switch from receiving state to drying state, and the drying tubes 4 in the discharge state switch to receiving state, which facilitates continuous drying of materials on the one hand, and continuous receiving and conveying of materials on the other hand.

[0111] A3, material drying, roasting tail gas enters the interior of the heat exchange chamber 100 through the air inlet pipe 14 and fully contacts the tube body 41 for heat exchange. After heat exchange, the tube body 41 heats the stored material. The gas generated after heat exchange passes through the isolation filter screen 42 and is then transported upward to the interior of the exhaust chamber 200, and then discharged through the second exhaust pipe 15.

[0112] A4, Material Discharge: When the rotating disk 3 is rotated and adjusted, the rotating disk 3 also drives the drying pipe 4 to switch from the drying state to the discharge state. The bottom of the pipe body 41 is automatically opened, so that the material stored inside the pipe body 41 is conveyed downward into the discharge chamber 300 under the action of gravity. The material enters the discharge port 12 through the discharge chamber 300 and is then discharged downward.

[0113] This facilitates independent material receiving and unloading during continuous heat exchange and drying processes.

[0114] Second embodiment:

[0115] Please refer to the following: Figures 8 to 9 Based on the charcoal powder drying equipment provided in the first embodiment of the present invention, the second embodiment of the present invention proposes another charcoal powder drying equipment. The second embodiment is merely a preferred embodiment of the first embodiment, and the implementation of the second embodiment will not affect the separate implementation of the first embodiment.

[0116] Specifically, the difference in the charcoal drying equipment provided in the second embodiment of the present invention is that the charcoal drying equipment further includes a connecting pipe 6, the two ends of which are fixedly connected to the first exhaust pipe 13 and the drying tank 1, and the output end of the connecting pipe 6 is aligned with the range of the feeding chamber 300.

[0117] In this embodiment, only when the drying tube 4 is in the discharge state can the waste heat exhaust gas entering the discharge chamber 300 be discharged upward through the range of the isolation filter 42. The waste heat exhaust gas flows slowly, and the material will not be carried into the range of the exhaust chamber 200 under the action of gravity, so that the falling material and the rising airflow do not affect each other.

[0118] The first exhaust pipe 13 is connected to the input end of the connecting pipe 6, and the output end of the connecting pipe 6 is connected to the drying tank 1. This facilitates the input of the waste heat exhaust gas after heat exchange from within the range of the feeding chamber 300. The waste heat exhaust gas then sequentially passes through the feeding chamber 300, the interior of the isolation filter 42, and the exhaust chamber 200, accelerating the transport of the gas generated during the drying process to the range of the exhaust chamber 200. Afterward, it is transported outward through the second exhaust pipe 15. This fully utilizes the heat in the waste heat exhaust gas and increases the flow velocity of the gas generated after heat exchange and drying.

[0119] Please refer to the following: Figures 9 to 10 The carbon powder drying equipment further includes a turbulence assembly 7, which includes a support plate 71, a turbulence shaft 72, and a transmission component 73. The support plate 71 is fixed inside the feed inlet 11. The turbulence shaft 72 is rotatably mounted on the top of the support plate 71. The rotation axis of the turbulence shaft 72 passes through the support plate 71 and extends to the bottom of the support plate 71. The transmission component 73 passes through the feed inlet 11 and is connected to the driving part of the driving component 2 and the rotating part of the turbulence shaft 72.

[0120] In this embodiment, a feeding gap is reserved between the support plate 71 and the feed port 11, so that the turbulence shaft 72 can stably pass through the feeding gap and convey the material downward when it rotates.

[0121] In this embodiment, the turbulence shaft 72 has a cross-shaped structure and is inserted within the range of the feed inlet 11.

[0122] While the driving component 2 controls one of the drying tubes 4 to enter the drying state from the receiving state, it also switches the other drying tube 4 from the drying state to the discharging state. At the same time, the driving component 2 also drives the turbulence shaft 72 to rotate synchronously through the transmission component 73, so as to turbulent the material in the range of the feed inlet 11 and prevent the material from being blocked inside the feed inlet 11.

[0123] In a preferred embodiment of this example, the transmission component 73 may include two pulleys and a belt. The belt drives the two pulleys, and the belt passes through the feed inlet 11 and is slidably connected. One pulley is fixed to the driving part of the driving component 2, and the other pulley is fixed to the rotating shaft of the turbulence shaft 72. This facilitates the control of the rotation adjustment of the turbulence shaft 72 by the driving component 2.

[0124] In another preferred embodiment of this example, the transmission component 73 may include two sprockets and a chain. The chain drives the two sprockets, and the chain passes through the feed port 11 and is slidably connected. One sprocket is fixed to the driving part of the driving component 2, and the other sprocket is fixed to the rotating shaft of the turbulence shaft 72. This facilitates the control of the rotation adjustment of the turbulence shaft 72 by the driving component 2.

[0125] The working principle of the charcoal drying equipment provided in this embodiment is as follows:

[0126] The waste heat exhaust gas delivered through the first exhaust pipe 13 is transported to the range of the feeding chamber 300 through the connecting pipe 6, which facilitates secondary drying of the falling material. The dried gas is then transported upward through the inside of the isolation filter 42. During the transport process, the gas generated by drying in the pipe body 41 in the discharge state is carried away and transported upward to the inside of the exhaust chamber 200, while the material is still discharged downward under the action of gravity, which facilitates the secondary utilization of the roasting exhaust gas.

[0127] While the drive component 2 drives the rotating disk 3 to rotate and adjust, the drive component 2 also drives the turbulence shaft 72 to rotate synchronously through the transmission component 73, so that the turbulence shaft 72 rotates stably on the support plate 71, which facilitates the rotation and turbulence of materials within the range of the feed inlet 11, and avoids material accumulation that prevents feeding.

[0128] While the drive unit 2 controls the state switching of the drying tube 4, it also achieves turbulence of the material in the feed inlet 11, preventing material from accumulating and failing to be discharged.

[0129] 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 method for purifying carbon from waste cathode carbon blocks, characterized in that, Includes the following steps: Step S1, raw material pretreatment: After the cathode carbon blocks are fully crushed and screened, the screened cathode carbon blocks are put into the carbon powder drying equipment for drying to obtain dried material. Step S2, calcination treatment: weigh the cathode carbon block and sodium carbonate, mix them and ball mill them, then place the mixture in a muffle furnace for calcination to obtain calcined material; the gas volatilized during the calcination process is oxidized by hypochlorous acid solution and collected. Step S3: Purification of carbon blocks. After the calcined material is cooled, it is treated with pure water immersion and solid-liquid separation to obtain filter residue A and filtrate A. Filter residue A is washed with water at room temperature. After washing and drying, high-purity carbon blocks are obtained.

2. The method for purifying carbon from waste cathode carbon blocks according to claim 1, characterized in that, In step S1, crushing equipment is used for crushing; during screening, the crushed carbon blocks are sieved through a 100-200 mesh sieve using a screening device.

3. The method for purifying carbon from waste cathode carbon blocks according to claim 1, characterized in that, In step S2, the cathode carbon block and sodium carbonate are placed in a planetary ball mill at a mass ratio of 1 to 1.33:1 and ball-milled for 15 minutes.

4. The method for purifying carbon from waste cathode carbon blocks according to claim 3, characterized in that, The roasting temperature in the muffle furnace is 850℃, and the roasting time is 3 hours.

5. The method for purifying carbon from waste cathode carbon blocks according to claim 4, characterized in that, In step S3, the calcined material is placed in a polytetrafluoroethylene beaker and soaked in water at a liquid-to-solid ratio of 5 to 7:

1. The mixture is then kept at 60°C in a water bath and stirred at 300 rpm for 3 hours.

6. The method for purifying carbon from waste cathode carbon blocks according to claim 5, characterized in that, In step S3, the water washing process is performed at a liquid-to-solid ratio of 4:

1.

7. The method for purifying carbon from waste cathode carbon blocks according to claim 1, characterized in that, It also includes the following steps: Step S4: Place filtrate A in a constant temperature water bath and stir. During the stirring process, introduce the gas collected in step S2 and add sodium hydroxide to adjust the pH to 9-11.

5. React and filter to obtain cryolite and filtrate B. In step S5, the filtrate B is evaporated and crystallized, and the crystallized product is selectively filtered to obtain sodium carbonate and sodium fluoride.

8. The method for purifying carbon from waste cathode carbon blocks according to claim 7, characterized in that, In step S4, the constant temperature water bath is stirred at a temperature of 60°C.

9. The method for purifying carbon from waste cathode carbon blocks according to claim 8, characterized in that, In step S5, selective filtration utilizes filter materials with different pore sizes to selectively filter the crystallized product sequentially, resulting in sodium carbonate with a particle size <50μm and sodium fluoride with a particle size >100μm.

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