Method for preparing silicon carbide by using cathode carbon block and coal gangue and reaction equipment

Abstract

The application provides a method for preparing silicon carbide by using cathode carbon blocks and coal gangue and a reaction device, and relates to the field of silicon carbide preparation. The method for preparing silicon carbide by using cathode carbon blocks and coal gangue comprises the following steps: S1: placing aluminum electrolysis cathode carbon blocks and coal gangue containing silicon dioxide after crushing, grinding and sieving into an oven for drying for standby; S2: mixing the dried cathode carbon blocks with a sodium hydroxide solution by using a reaction device, and then performing reaction at a temperature of 60-75 DEG C under a ultrasonic power of 300-400 W, and then performing solid-liquid separation to obtain an alkali leaching solution and an alkali leaching residue. The method for preparing silicon carbide by using cathode carbon blocks and coal gangue provided by the application realizes directional separation of impurities such as fluorine, aluminum and sodium in the cathode carbon blocks by using an ultrasonic-assisted alkali leaching-acid leaching synergistic process, realizes directional conversion of silicon elements by using the ultrasonic cavitation effect, and realizes directional conversion of silicon elements by using the ultrasonic cavitation effect, and high-purity carbon matrix is obtained, and high-purity silicon carbide is prepared by realizing directional conversion of silicon elements by using the high-temperature acid leaching activated coal gangue through a carbothermic reduction method.

Description

Technical Field

[0001] This invention relates to the field of silicon carbide preparation, and more particularly to a method and reaction equipment for preparing silicon carbide using cathode carbon blocks and coal gangue. Background Technology

[0002] Cathode carbon blocks are hazardous byproducts discharged from shut-down electrolytic cells in the aluminum electrolysis industry. During operation, these blocks are inevitably corroded by high-temperature electrolytes, molten aluminum, and metallic sodium. Cathode carbon blocks are primarily composed of carbon, fluorides, and other inorganic impurities. While carbon and fluorides have high recovery potential, cyanides and soluble fluoride salts are the main environmentally hazardous components, severely impacting plant and animal health and ecological balance. Many countries have classified them as hazardous solid waste.

[0003] Currently, the processing of cathode carbon blocks includes using them as raw materials or additives in industries such as cement, steel, and copper recycling. Hydrometallurgical processing techniques include acid leaching, flotation, leaching with soluble aluminum salt solutions, alkali leaching, and acid-alkali co-treatment. However, due to the complexity of impurities and the lack of efficient processing methods, the purity of carbon powder obtained by existing processes is not ideal.

[0004] Coal gangue, as an industrial waste, is rich in silicon and is a potential silicon source. Silicon carbide (SiC) powder has advantages such as stable chemical properties, high thermal conductivity, low coefficient of thermal expansion, and good wear resistance. However, there is still room for improvement in the production of silicon carbide by utilizing cathode carbon blocks and coal gangue as waste.

[0005] Therefore, it is necessary to provide a method and reaction equipment for preparing silicon carbide using cathode carbon blocks and coal gangue to solve the above-mentioned technical problems. Summary of the Invention

[0006] This invention provides a method for preparing silicon carbide using cathode carbon blocks and coal gangue, solving the problem of how to utilize cathode carbon blocks and coal gangue to produce silicon carbide from waste.

[0007] To solve the above-mentioned technical problems, the present invention provides a method for preparing silicon carbide using cathode carbon blocks and coal gangue, comprising the following steps:

[0008] S1: After crushing, grinding and sieving aluminum electrolytic cathode carbon blocks and silica-containing coal gangue, place them in an oven to dry for later use.

[0009] S2: Using a reaction device, the dried cathode carbon block is mixed with sodium hydroxide solution, and after reacting with an ultrasonic power of 300~400W at a temperature of 60~75℃, the solid and liquid are separated to obtain alkaline leaching solution and alkaline leaching residue.

[0010] S3: Use reaction equipment to mix the alkaline leaching residue and hydrochloric acid solution, react with 300~400W ultrasonic power at 60~75℃, and then separate the solid and liquid to obtain acid leaching solution and carbon powder;

[0011] S4: Using a reaction device, dry coal gangue is mixed with hydrochloric acid solution, and reacted at 60-75℃ with an ultrasonic power of 300-400W. After solid-liquid separation, silicon dioxide is obtained.

[0012] S5: Mix purified carbon powder and silica, add anhydrous ethanol as an surfactant, place in a planetary ball mill to ball mill to form a precursor, and then press the precursor into shape.

[0013] S6: Place the pressed precursor in a corundum crucible, then place it in a tube furnace and heat it to 1500~1700℃ under argon atmosphere protection to obtain coarse SiC powder.

[0014] S7: After mixing and reacting the obtained crude SiC powder with hydrofluoric acid, the mixture is filtered and dried to obtain the SiC product.

[0015] Preferably, in step S2, a 2-3 mol / L sodium hydroxide solution is used and mixed with the dried cathode carbon block at a solid-liquid ratio of 1:3 to 1:4.

[0016] Preferably, in step S3, a 2-3 mol / L hydrochloric acid solution is mixed with the alkaline leaching residue at a solid-liquid ratio of 1:3 to 1:4.

[0017] Preferably, in step S4, a 2-3 mol / L hydrochloric acid solution is mixed with the dried coal gangue at a solid-liquid ratio of 1:3 to 1:4.

[0018] The present invention also provides a reaction apparatus for use in steps S2 to S4 of the method for preparing silicon carbide using cathode carbon blocks and coal gangue, comprising: a support platform;

[0019] The reaction structure includes a mounting plate, a reaction cylinder, an ultrasonic disperser, and a heating device. The mounting plate is rotatably mounted on the support, the reaction cylinder is mounted on the support, the discharge pipe of the reaction cylinder passes through the mounting plate, and the heating device is sleeved on the reaction cylinder.

[0020] A lifting device, wherein the ultrasonic disperser is installed on the discharge pipe of the lifting device and aligned with the opening of the reaction cylinder;

[0021] A filtration device is provided, wherein the filtration device and the reaction cylinder are set at a preset angle relative to the rotation center of the mounting plate. The filtration device includes a mounting frame, a bottom cylinder, a filter cylinder, and a filtration structure. The bottom cylinder is mounted on the mounting frame. The filter cylinder is detachably connected to the top of the bottom cylinder. The filtration structure is rotatably mounted inside the filter cylinder. A flange is provided inside the bottom cylinder to support the filtration structure.

[0022] The rotating device is used to drive the mounting plate to rotate when performing solid-liquid separation on the material in the reaction cylinder.

[0023] Preferably, the rotating device includes a fixed plate, a motor, and a rotating column. The motor is mounted below the support through the fixed plate, the rotating column passes through the support and is rotatably connected to the support, and the bottom end of the rotating column is fixedly connected to the motor.

[0024] The lifting device is installed at the top of the rotating column, and the rotating column is detachably connected to the mounting plate via fittings.

[0025] Preferably, the reaction structure further includes a cylinder cover, which is installed on the discharge pipe of the lifting device, and the ultrasonic disperser passes through the cylinder cover.

[0026] Preferably, a drive block is installed on the rotating column, the drive block has an insertion hole, the mounting plate has an assembly hole, the insertion hole and the assembly hole are concentrically arranged, the assembly is cylindrical, the assembly is installed on the discharge pipe of the lifting device and suspended above the insertion hole;

[0027] When the lifting device drives the cylinder cover to seal the top of the reaction cylinder, the fitting passes through the insertion hole and the assembly hole in sequence;

[0028] The cylinder cover is symmetrically equipped with mounting plates, and the mounting plates have mounting holes. Both sides of the filter cylinder are threaded with mounting pins. When the cylinder cover is rotated above the filter cylinder, the two mounting plates are aligned with the two mounting pins.

[0029] Preferably, the filtration structure includes a filter element, a gear, and two rotating shafts. The two sides of the filter element are rotatably mounted inside the filter cartridge via corresponding rotating shafts. The gear is mounted on one of the rotating shafts and is located outside the filter cartridge.

[0030] The inner wall of the reaction cylinder is equipped with a toothed plate. When the filter cylinder is suspended above the reaction cylinder, the toothed surface of the toothed plate is aligned with the gear.

[0031] Preferably, the filtration device further includes a positioning element for axially limiting the rotating shaft, and a lifting shaft is installed on the inner wall of the reaction cylinder above the toothed plate via a connecting block;

[0032] When the filter cartridge is suspended above the reaction cylinder, the lifting shaft is aligned with the positioning member. During the process of the lifting device lowering the filter cartridge into the reaction cylinder, the lifting shaft and the positioning member act together to unlock the rotating shaft.

[0033] Compared with related technologies, the method for preparing silicon carbide using cathode carbon blocks and coal gangue provided by the present invention has the following beneficial effects:

[0034] This invention provides a method for preparing silicon carbide using cathode carbon blocks and coal gangue. The aluminum electrolysis cathode carbon blocks are treated by an ultrasonic-assisted alkaline leaching-acid leaching synergistic process. By utilizing the ultrasonic cavitation effect, the impurities such as fluorine, aluminum and sodium in the cathode carbon blocks are efficiently and directionally separated to obtain a high-purity carbon matrix. The matrix is ​​then converted into silicon by a carbothermal reduction method with coal gangue activated by high-temperature acid leaching to prepare high-purity silicon carbide.

[0035] This process constructs a synergistic utilization system of "cathode carbon block carbon source - coal gangue silicon source", which not only realizes the efficient separation and resource utilization of elements such as fluorine, aluminum, and silicon, but also provides a new path for the synergistic high-value utilization of hazardous solid waste from aluminum electrolysis and coal-based solid waste. It promotes the upgrading of industrial waste from "harmless treatment" to "targeted component recovery and material utilization", and provides a closed-loop solution for the synergistic disposal and high-value utilization of hazardous waste from aluminum electrolysis and the coal industry. Attached Figure Description

[0036] Figure 1 This is a flowchart illustrating the steps of the method for preparing silicon carbide using cathode carbon blocks and coal gangue provided by the present invention.

[0037] Figure 2 This is a schematic diagram of the reaction apparatus provided by the present invention;

[0038] Figure 3 for Figure 2 A partial cross-sectional view of the reaction equipment shown;

[0039] Figure 4 for Figure 1 The cross-sectional view of the filter device shown;

[0040] Figure 5 for Figure 2 The enlarged schematic diagram of part A shown below;

[0041] Figure 6 A schematic diagram showing the ultrasonic disperser provided by the present invention in operation;

[0042] Figure 7 This is a schematic diagram of the usage state of the reaction cylinder provided by the present invention, wherein, Figure 7 (a) is a schematic diagram of the reaction vessel in the reaction state. Figure 7 (b) Schematic diagram of solid-liquid separation at the reaction chamber;

[0043] Figure 8 This is a schematic diagram illustrating the principle of separating the filter cartridge and the bottom cylinder provided by the present invention, wherein... Figure 8 Image (a) is a schematic diagram of the assembly pin and the assembly plate. Figure 8 (b) is a schematic diagram showing the filter cartridge moving upwards and separating from the bottom cylinder;

[0044] Figure 9 A schematic diagram showing the state in which the filter cartridge provided by the present invention enters the reaction cylinder to feed materials into the reaction cylinder;

[0045] Figure 10 for Figure 9 The enlarged schematic diagram of part B is shown.

[0046] Numbering on the map:

[0047] 1. Support platform;

[0048] 2. Reaction structure; 21. Mounting plate; 22. Reaction cylinder; 23. Cylinder cover; 24. Ultrasonic disperser; 25. Heating device; 26. Assembly plate; 211. Assembly hole; 221. Lifting shaft; 222. Toothed plate;

[0049] 3. Rotating device; 31. Fixed plate; 32. Motor; 33. Rotating column; 34. Driving block; 341. Insertion hole;

[0050] 4. Lifting device; 41. Lifting cylinder; 42. Lifting plate; 43. Telescopic rod;

[0051] 5. Filter device; 51. Bottom cylinder; 52. Filter cartridge; 53. Filter structure; 54. Positioning component; 55. Mounting bracket; 521. Assembly pin;

[0052] 531. Filter element; 532. Shaft; 533. Gear; 534. Horizontal plane;

[0053] 541. Support block; 542. Connecting shaft; 543. U-shaped sleeve; 544. Lifting block;

[0054] 6. Assembly parts. Detailed Implementation

[0055] 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.

[0056] This invention provides a method and reaction equipment for preparing silicon carbide using cathode carbon blocks and coal gangue.

[0057] Please refer to the following: Figure 1 In one embodiment of the present invention, the method for preparing silicon carbide using cathode carbon blocks and coal gangue includes the following steps:

[0058] S1: After crushing, grinding and sieving aluminum electrolytic cathode carbon blocks and silica-containing coal gangue, place them in an oven to dry for later use.

[0059] S2: Using a reaction device, the dried cathode carbon block is mixed with sodium hydroxide solution, and after reacting with an ultrasonic power of 300~400W at a temperature of 60~75℃, the solid and liquid are separated to obtain alkaline leaching solution and alkaline leaching residue.

[0060] S3: Use a reaction device to mix the alkaline leaching residue and hydrochloric acid solution, react with 350~450W ultrasonic power at 60~75℃, and then separate the solid and liquid to obtain acid leaching solution and carbon powder.

[0061] S4: Using a reaction device, dry coal gangue is mixed with hydrochloric acid solution, and reacted at 60-75℃ with ultrasonic power of 350-450W. After solid-liquid separation, silicon dioxide is obtained.

[0062] S5: Mix purified carbon powder and silica, add anhydrous ethanol as an surfactant, place in a planetary ball mill to ball mill to form a precursor, and then press the precursor into shape.

[0063] S6: Place the pressed precursor in a corundum crucible, then place it in a tube furnace and heat it to 1500~1700℃ under argon atmosphere protection to obtain coarse SiC powder.

[0064] S7: After mixing and reacting the obtained crude SiC powder with hydrofluoric acid, the mixture is filtered and dried to obtain the SiC product.

[0065] This invention processes aluminum electrolysis cathode carbon blocks using an ultrasonic-assisted alkaline leaching-acid leaching synergistic process. By utilizing the ultrasonic cavitation effect, it achieves efficient and directional separation of impurities such as fluorine, aluminum, and sodium in the cathode carbon blocks, obtaining a high-purity carbon matrix. This matrix is ​​then used to achieve directional conversion of silicon elements with coal gangue activated by high-temperature acid leaching via a carbothermic reduction method, thus preparing high-purity silicon carbide.

[0066] This process constructs a synergistic utilization system of "cathode carbon block carbon source - coal gangue silicon source", which not only realizes the efficient separation and resource utilization of elements such as fluorine, aluminum, and silicon, but also provides a new path for the synergistic high-value utilization of hazardous solid waste from aluminum electrolysis and coal-based solid waste. It promotes the upgrading of industrial waste from "harmless treatment" to "targeted component recovery and material utilization", and provides a closed-loop solution for the synergistic disposal and high-value utilization of hazardous waste from aluminum electrolysis and the coal industry.

[0067] The silicon carbide prepared by this invention can be used as an auxiliary material for the negative electrode of a battery.

[0068] As a preferred embodiment, coal gangue with a silica content higher than 90% is selected in S1.

[0069] In a preferred embodiment, a 2-3 mol / L sodium hydroxide solution is used in step S2, and it is mixed with the dried cathode carbon block at a solid-liquid ratio of 1:3 to 1:4.

[0070] In a preferred embodiment, in step S3, a 2-3 mol / L hydrochloric acid solution is mixed with the alkaline leaching residue at a solid-liquid ratio of 1:3 to 1:4.

[0071] In a preferred embodiment, in step S4, a 2-3 mol / L hydrochloric acid solution is mixed with the dried coal gangue at a solid-liquid ratio of 1:3 to 1:4.

[0072] Specifically, the present invention includes the following embodiments:

[0073] Example 1

[0074] S1: After crushing the aluminum electrolytic cathode carbon block and coal gangue with a silica content of more than 90%, grind them through a planetary ball mill and pass them through a 200-mesh sieve. Then, place them in an oven and dry them at 100°C for 12 hours for later use.

[0075] S2: Weigh 100g of dried cathode carbon block and mix it with 2mol / L sodium hydroxide solution at a solid-liquid ratio of 1:4. React at 68℃ for 60min with an ultrasonic power of 350W to remove impurities such as alumina and cryolite. Separate the solid and liquid to obtain alkaline leaching solution and alkaline leaching residue.

[0076] S3: Mix the alkaline leaching residue and 2 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:4, and react at 68℃ for 60 min with an ultrasonic power of 350W to further remove metallic impurities such as calcium fluoride. The solid and liquid are separated to obtain acid leaching solution and high-purity carbon powder. The acid leaching solution and alkaline leaching solution can be collected and valuable elements such as sodium, aluminum and fluorine can be recovered by neutralization and precipitation.

[0077] S4: The dried coal gangue was mixed with 2 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:4 and reacted at 68℃ for 60 min with an ultrasonic power of 350W to remove impurities such as iron oxide and aluminum oxide. The solid and liquid were separated to obtain high-purity silicon dioxide.

[0078] S5: Weigh 25g of purified carbon powder and silicon dioxide and mix them in a mass ratio of 3:1. Add anhydrous ethanol as an surfactant in a solid-liquid ratio of 3:1 and place it in a planetary ball mill and ball mill for 2 hours to form a precursor. After ball milling, press the precursor into shape under pressure.

[0079] S6: The pressed precursor is placed in a corundum crucible and then placed in a tube furnace under argon atmosphere protection at a heating rate of 5℃ / min to 1600℃ and held for 4h to obtain SiC powder.

[0080] S7: The obtained SiC powder is mixed with 1 mol / L hydrofluoric acid at a solid-liquid ratio of 4:1 and reacted for 2 hours to remove the silicon oxides involved. After filtration and drying, a high-purity SiC product is obtained.

[0081] Example 2

[0082] S1: After crushing the aluminum electrolytic cathode carbon block and coal gangue with a silica content of more than 90%, grind them through a planetary ball mill and pass them through a 150-mesh sieve. Then, place them in an oven and dry them at 100°C for 12 hours for later use.

[0083] S2: Weigh 200g of dried cathode carbon block and mix it with 3mol / L sodium hydroxide solution at a solid-liquid ratio of 1:3. React at 78℃ for 45min with an ultrasonic power of 450W to remove impurities such as alumina and cryolite. The solid and liquid are separated to obtain alkaline leaching solution and alkaline leaching residue.

[0084] S3: Mix the alkaline leaching residue and 3mol / L hydrochloric acid solution at a solid-liquid ratio of 1:3, and react at 78℃ for 45 minutes with an ultrasonic power of 450W to further remove metallic impurities such as calcium fluoride. The solid and liquid are separated to obtain acid leaching solution and high-purity carbon powder. The acid leaching solution and alkaline leaching solution can be collected and valuable elements such as sodium, aluminum and fluorine can be recovered by neutralization and precipitation.

[0085] S4: The dried coal gangue was mixed with 3 mol / L hydrochloric acid solution at a solid-liquid ratio of 1:3 and reacted at 78℃ for 60 min with an ultrasonic power of 450W to remove impurities such as iron oxide and aluminum oxide. The solid and liquid were separated to obtain high-purity silica.

[0086] S5: Weigh 50g of purified carbon powder and silicon dioxide and mix them in a mass ratio of 2:1. Add anhydrous ethanol as an surfactant in a solid-liquid ratio of 4:1 and place it in a planetary ball mill and ball mill for 3 hours to form a precursor. After ball milling, press the precursor into shape under pressure.

[0087] S6: The pressed precursor is placed in a corundum crucible and then placed in a tube furnace under argon atmosphere protection at a heating rate of 5℃ / min to 1700℃ and held for 3h to obtain SiC powder.

[0088] S7: The obtained SiC powder is mixed with 1 mol / L hydrofluoric acid at a solid-liquid ratio of 4:1 and reacted for 2 hours to remove the silicon oxides involved. After filtration and drying, a high-purity SiC product is obtained.

[0089] The present invention also provides a reaction apparatus.

[0090] The reaction equipment is used in steps S2 to S4 of the method for preparing silicon carbide using cathode carbon blocks and coal gangue. Of course, the reaction equipment proposed in this invention is not limited to steps S2 to S4 of this invention, but can also be applied to other production processes where the reactants have precipitates and require solid-liquid separation in mixed reactions, such as the production of aluminum hydroxide using sodium aluminate and acid.

[0091] Please see Figures 2 to 4 A reaction apparatus, comprising: a support 1;

[0092] The reaction structure 2 includes a mounting plate 21, a reaction cylinder 22, an ultrasonic disperser 24, and a heating device 25. The mounting plate 21 is rotatably mounted on the support 1, the reaction cylinder 22 is mounted on the support 1, the discharge pipe of the reaction cylinder 22 passes through the mounting plate 21, and the heating device 25 is sleeved on the reaction cylinder 22.

[0093] The lifting device 4, wherein the ultrasonic disperser 24 is installed on the discharge pipe of the lifting device 4 and aligned with the opening of the reaction cylinder 22;

[0094] The filter device 5 is set at a preset angle relative to the rotation center of the reaction cylinder 22 and the mounting plate 21. The filter device 5 includes a mounting frame 55, a bottom cylinder 51, a filter cylinder 52, and a filter structure 53. The bottom cylinder 51 is mounted on the mounting frame 55. The filter cylinder 52 is detachably connected to the top of the bottom cylinder 51. The filter structure 53 is rotatably mounted inside the filter cylinder 52. The bottom cylinder 51 has a flange inside to support the filter structure 53.

[0095] The rotating device 3 is used to drive the mounting plate 21 to rotate when performing solid-liquid separation on the material in the reaction cylinder 22.

[0096] The top of the filter cartridge 52 is flush with the bottom of the mounting plate 21. A valve is provided on the discharge pipe of the reaction cylinder 22, and the bottom of the discharge end is preferably flush with the bottom of the mounting plate 21. A temperature detector (not shown) is also provided inside the reaction cylinder 22. The reaction equipment provided by the present invention is mainly used in small production scenarios such as laboratories.

[0097] In use, the cathode carbon block to be reacted and sodium hydroxide are added into the reaction cylinder 22. Then, the lifting device 4 lowers the ultrasonic disperser 24 so that the ultrasonic probe of the ultrasonic disperser 24 enters the mixed solution in the reaction cylinder 22. The two materials react quickly through the ultrasonic cavitation effect. At the same time, the heating device 25 heats the mixed solution in the reaction cylinder 22 to the preset temperature.

[0098] After the reaction is completed, the rotating device 3 drives the mounting plate 21 to rotate by a preset angle so that the reaction cylinder 22 is aligned with the filter cylinder 52. At this time, the mounting plate 21 seals the top of the filter cylinder 52, and the discharge pipe of the reaction cylinder 22 is connected to the inside of the filter cylinder 52. The valve located on the discharge pipe is opened, and the solution inside the reaction cylinder 22 enters the filter cylinder 52 through the discharge pipe. The filtration structure 53 filters out the alkaline leaching residue in the solution, and the solution passes through the filtration structure 53 into the bottom cylinder 51.

[0099] After filtration, the rotating device 3 drives the mounting plate 21 to rotate in the opposite direction to its original position and separate it from the filtering device 5. Then, the filter cylinder 52 is separated from the bottom cylinder 51, and the filtered alkaline leaching residue is placed back into the filter cylinder 52. Then, hydrochloric acid solution is added into the filter cylinder 52 to carry out step S3. The reaction and filtration are carried out in the same way, so that the reaction of the mixed solution and solid-liquid separation can be realized quickly. The reaction between steps can be carried out quickly and continuously, improving the reaction efficiency.

[0100] The subsequent step S4 is performed in the same way.

[0101] The filter structure 53 is rotatably installed inside the filter cartridge 52. When the filter cartridge 52 is taken out and the filtered solid is poured into the reaction cylinder 22, the filter cartridge 52 can be aligned with the reaction cylinder 22, and then the filter structure 53 can be flipped over to facilitate the addition of solid material into the reaction cylinder 22.

[0102] Furthermore, by providing a flange inside the bottom cylinder 51 to support the filter structure 53, the filter structure 53 is axially limited, enabling it to stably perform solid-liquid separation.

[0103] A sealing ring is preferably provided at the bottom of the mounting plate 21. When the mounting plate 21 drives the reaction cylinder 22 to align with the filter cylinder 52, the sealing ring fits against the top of the filter cylinder 52 to seal the filter cylinder 52.

[0104] The bottom of the bottom cylinder 51 is provided with a liquid outlet pipe and a valve. A gas supply pipe is provided on one side of the bottom cylinder 51. Preferably, the gas supply pipe is connected to a vacuum pump through a pipeline, so that the vacuum pump can generate negative pressure inside the filter device 5, thereby accelerating the filtration speed.

[0105] When solid materials need to be cleaned, the solid materials can be added into the reaction cylinder 22, followed by the addition of cleaning solutions such as deionized water, and then ultrasonic cleaning is performed through the ultrasonic disperser 24.

[0106] In this embodiment, the rotation center of the filter device 5 and the reaction cylinder 22 relative to the mounting plate 21 is set at 45~180°, and 90°.

[0107] In this embodiment, the heating device 25 includes a heating jacket, an inlet pipe, and an exhaust pipe. The heating jacket is fitted onto the reaction cylinder 22. The inlet pipe and the exhaust pipe are respectively installed on the reaction cylinder 22 and communicate with the interior of the reaction cylinder 22. A partition is provided inside the reaction cylinder 22 to separate the inlet pipe and the exhaust pipe. The inlet pipe and the exhaust pipe are respectively connected to the output end and the input end of the heating module. The heating module inputs the heating medium (gas or liquid) into the heating jacket through the inlet pipe. The exhaust pipe delivers the heat-exchanged heating medium to the heating module to achieve circulation.

[0108] In other embodiments, the heating device 25 includes a heating sleeve and an electric heating wire. The heating sleeve is fitted onto the reaction cylinder 22, and the electric heating wire is installed inside the heating sleeve to heat the reaction cylinder 22.

[0109] like Figure 1 The ultrasonic diffuser 24 is connected to the ultrasonic generator via a cable.

[0110] In this embodiment, the filter cartridge 52 and the bottom cylinder 51 are connected by insertion. The bottom of the filter cartridge 52 is provided with an annular protrusion, and the top of the bottom cylinder 51 is provided with an annular groove. During assembly, the annular protrusion at the bottom of the filter cartridge 52 is inserted into the annular groove of the bottom cylinder 51.

[0111] In other embodiments, a clamp can be provided, which is fitted at the connection between the filter cartridge 52 and the bottom cylinder 51, and then the clamp is locked with bolts.

[0112] Please see Figure 4 In this embodiment, the rotating device 3 includes a fixed plate 31, a motor 32 and a rotating column 33. The motor 32 is installed below the support 1 through the fixed plate 31. The rotating column 33 passes through the support 1 and is rotatably connected to the support 1. The bottom end of the rotating column 33 is fixedly connected to the motor 32.

[0113] The lifting device 4 is installed on the top of the rotating column 33, and the rotating column 33 is detachably connected to the mounting plate 21 via the fitting 6.

[0114] When the position of the reaction cylinder 22 needs to be adjusted, the motor 32 drives the rotating column 33 to rotate, and the rotating column 33 drives the mounting plate 21 to rotate through the assembly 6, thereby causing the reaction cylinder 22 to rotate accordingly.

[0115] Furthermore, the lifting device 4 is installed on the rotating column 33. When the reaction cylinder 22 is aligned with the filter cylinder 52 for filtration, the lifting device 4 can drive the ultrasonic disperser 24 to rotate. Thus, during the filtration operation, the ultrasonic disperser 24 works to vibrate the solution in the reaction cylinder 22, which is beneficial for the filtration operation.

[0116] The base of the support 1 is provided with multiple legs, and the fixing plate 31 is installed between the multiple legs; of course, the fixing plate 31 can also be supported by legs.

[0117] In other embodiments, the output end of the motor 32 can be directly fixedly connected to the mounting plate 21, and the lifting device 4 can be installed on the mounting plate 21.

[0118] In this embodiment, the lifting device 4 includes a lifting cylinder 41, a lifting plate 42, and multiple telescopic rods 43. The lifting cylinder 41 is mounted on the rotating column 33, the lifting plate 42 is mounted on the output end of the lifting cylinder 41, and the multiple telescopic rods 43 are arranged around the lifting cylinder 41. The bottom end of the telescopic rod 43 is mounted on the rotating column 33, and the top telescopic end is connected to the lifting plate 42.

[0119] The ultrasonic disperser 24 is installed on the lifting plate 42;

[0120] The lifting cylinder 41 can be a pneumatic cylinder, a hydraulic cylinder, or an electric pusher cylinder.

[0121] In other embodiments, the lifting cylinder 41 can be replaced with a lead screw structure, a belt lifting structure, etc., and the corresponding lifting plate 42 can be installed on the nut of the lead screw structure or on the belt of the belt lifting structure, etc.

[0122] Please see Figure 2 and Figure 3 The reaction structure 2 also includes a cylinder cover 23, which is installed on the discharge pipe of the lifting device 4, and the ultrasonic disperser 24 passes through the cylinder cover 23.

[0123] By setting the lid 23, during the reaction, after the ultrasonic probe of the ultrasonic disperser 24 is lowered by the lifting device 4 into the reaction solution, the lid 23 is fitted onto the reaction cylinder 22 to form a sealed reaction space, preventing foreign objects from entering and heat loss.

[0124] Depending on the reaction conditions, an exhaust pipe and a feed pipe (not shown in the figure) can be connected to the cylinder cover 23, and valves are installed on the exhaust pipe and the feed pipe respectively.

[0125] Please see Figure 3 As an optional embodiment, a driving block 34 is installed on the rotating column 33, and an insertion hole 341 is provided on the driving block 34. An assembly hole 211 is provided on the mounting plate 21. The insertion hole 341 and the assembly hole 211 are concentrically arranged. The assembly 6 is cylindrical and is installed on the discharge pipe of the lifting device 4 and suspended above the insertion hole 341.

[0126] When the lifting device 4 drives the cylinder cover 23 to block the top of the reaction cylinder 22, the fitting 6 passes through the insertion hole 341 and the assembly hole 211 in sequence;

[0127] The cylinder cover 23 is symmetrically equipped with mounting plates 26, and the mounting plates 26 are provided with mounting holes. Both sides of the filter cylinder 52 are threadedly connected with mounting pins 521. When the cylinder cover 23 is rotated above the filter cylinder 52, the two mounting plates 26 are aligned with the two mounting pins 521.

[0128] The assembly plate 26 is longer than the ultrasonic disperser 24, and the mounting holes on the assembly plate 26 are located below the ultrasonic disperser 24.

[0129] During the reaction, the lifting device 4 lowers the ultrasonic disperser 24, placing it inside the reaction cylinder 22. Simultaneously, the cylinder cover 23 is fitted onto the reaction cylinder 22, and the lifting device 4 drives the assembly 6 to pass through the insertion hole 341 and the assembly hole 211 in sequence, thereby connecting the mounting plate 21 and the driving block 34. Figure 6 When solid-liquid separation is required, the motor 32 drives the rotating column 33 to rotate. The rotating column 33, through the drive block 34 and the assembly 6, can drive the mounting plate 21 to rotate, thereby driving the reaction cylinder 22 to rotate to align with the filter cylinder 52. The lifting device 4 also rotates accordingly. After filtration is completed, the mounting plate 21 drives the reaction cylinder 22 to rotate back to its original position.

[0130] When the filtered alkaline leaching residue needs to be added to the reaction cylinder 22, the lifting device 4 raises the ultrasonic disperser 24 to move it out of the reaction cylinder 22. Simultaneously, the lifting device 4 causes the assembly 6 to separate from the assembly hole 211 and the insertion hole 341. At this time, when the rotating device 3 drives the lifting device 4 to rotate, it will not cause the mounting plate 21 to rotate, meaning the reaction cylinder 22 will not rotate. The rotating device 3 drives the lifting device 4 to rotate the cylinder cover 23, aligning the cylinder cover 23 with the filter cylinder 52 and the two assembly plates 26 with the two assembly pins 521. The lifting device 4 lowers the cylinder cover 23, causing the two assembly plates 26 to lower, aligning the mounting holes of the assembly plates 26 with the assembly pins 521. Then, the assembly pins 521 are screwed so that their ends are inserted into the mounting holes. Figure 8 (a)

[0131] Then, the lifting device 4 lifts the cylinder cover 23, which, through the assembly plate 26 and the assembly pin 521, drives the filter cylinder 52 to move upward, as shown. Figure 8 (b) When the height of the filter cylinder 52 is higher than that of the reaction cylinder 22, the rotating device 3 rotates the lifting device 4 to align the filter cylinder 52 with the reaction cylinder 22; the lifting device 4 lowers the filter cylinder 52 so that it enters the reaction cylinder 22, and the subsequent rotating filtration structure 53 realizes the automatic addition of the separated solid material into the reaction cylinder 22;

[0132] Thus, in one state, the lifting device 4 is used to drive the ultrasonic disperser 24 into the reaction cylinder 22 for ultrasonic reaction, and in another state, it cooperates with the rotating device 3 to add the material in the filter cylinder 52 into the reaction cylinder 22. In the switching of the state of the lifting device 4, the usage state of the rotating device 3 is switched, which is used to drive the mounting plate 21 and the lifting device 4 to rotate simultaneously, or to drive the lifting device 4 to rotate alone.

[0133] In this embodiment, two drive blocks 34 are preferably installed symmetrically on the rotating column 33. Four mounting holes 211 are preferably arranged in a circular array with the center line of the rotating column 33. Two mounting holes 211 are aligned with the insertion holes 341 on the two drive blocks 34, and the other two are set at a 90-degree angle. A through hole is also provided on the support 1 corresponding to the other two mounting holes 211.

[0134] Thus, when the cover 23 is aligned with the filter cartridge 52, the fitting 6 can be aligned with the other two mounting holes 211 and the through hole. Thus, when the cover 23 is lowered to align the mounting hole of the mounting plate 26 with the mounting pin 521, the fitting 6 can pass through the corresponding mounting hole 211 and the through hole, so that the fitting 6 will not be blocked.

[0135] In other embodiments, the assembly 6 can also be configured as a positioning pin. When it is necessary to drive the reaction cylinder 22 to rotate, the positioning pin is passed through the insertion hole 341 and the assembly hole 211 to connect the mounting plate 21 and the rotating column 33.

[0136] Please see Figure 4 In this example, the filter structure 53 includes a filter element 531, a gear 533 and two rotating shafts 532. The two sides of the filter element 531 are rotatably mounted inside the filter cartridge 52 via corresponding rotating shafts 532. The gear 533 is mounted on one of the rotating shafts 532 and is located outside the filter cartridge 52.

[0137] The inner wall of the reaction cylinder 22 is equipped with a toothed plate 222. When the filter cylinder 52 is suspended above the reaction cylinder 22, the tooth surface of the toothed plate 222 is aligned with the gear 533.

[0138] The rotating shaft 532 passes through the filter cartridge 52 and is rotatably connected to the filter cartridge 52;

[0139] When the filter cartridge 52 is suspended above the reaction cylinder 22, the tooth surface of the toothed plate 222 is aligned with the gear 533. At this time, the lifting device 4 lowers the filter cartridge 52. During the descent, the gear 533 is acted upon by the tooth surface of the toothed plate 222, thereby driving the rotating shaft 532 to rotate. The rotating shaft 532 drives the filter element 531 to rotate and flip, causing the solid material above the filter element 531 to fall into the reaction cylinder 22, thus automatically allowing the filtered solid material to enter the reaction cylinder 22 for cleaning or subsequent reaction operations.

[0140] In this embodiment, when the gear 533 and the toothed plate 222 are fully engaged, the rotating shaft 532 drives the filter element 531 to rotate 180 degrees, thereby facilitating the solid material on the filter element 531 to fall into the reaction cylinder 22.

[0141] The filter element 531 includes a perforated plate and a filter screen, with the filter screen mounted on the perforated plate and two rotating shafts 532 mounted on both sides of the perforated plate.

[0142] Filter element 531, assembly plate 26, toothed plate 222, etc. are all made of corrosion-resistant materials.

[0143] In other embodiments, gear 533 may be replaced by a rotary motor, which is mounted on filter cartridge 52 via a bracket, and the upper shaft of the rotary motor is connected to a rotating shaft 532.

[0144] Please see Figure 5 As a preferred embodiment, the filter device 5 further includes a positioning member 54, which is used to axially limit the rotating shaft 532. The inner wall of the reaction cylinder 22 and above the toothed plate 222 is equipped with a lifting shaft 221 via a connecting block.

[0145] When the filter cartridge 52 is suspended above the reaction cylinder 22, the lifting shaft 221 is aligned with the positioning member 54. During the process of the lifting device 4 lowering the filter cartridge 52 into the reaction cylinder 22, the lifting shaft 221 and the positioning member 54 work together to unlock the rotating shaft 532.

[0146] By setting the positioning component 54 to limit the axial movement of the rotating shaft 532, the filter element 531 will not rotate axially during the process of lifting the filter cylinder 52 through the lifting device 4, the cylinder cover 23 and the assembly plate 26, and the material on it will not spill.

[0147] Furthermore, during the process of the lifting device 4 lowering the filter cylinder 52 into the reaction cylinder 22, the lifting shaft 221 interacts with the positioning member 54, causing the positioning member 54 to unlock the rotating shaft 532, thus achieving automatic unlocking and making it convenient to use;

[0148] Furthermore, after unlocking, gear 533 interacts with gear plate 222;

[0149] like Figure 5 In one embodiment, the positioning member 54 includes a support block 541, a connecting shaft 542, a U-shaped sleeve 543, and a lifting block 544. The support block 541 is fixedly connected to the filter cartridge 52, the connecting shaft 542 passes through the support block 541, the lifting block 544 and the U-shaped sleeve 543 are respectively installed at the top and bottom ends of the connecting shaft 542, the U-shaped sleeve 543 is sleeved on the horizontal surface 534 of a rotating shaft 532, and a through hole is provided on the lifting block 544.

[0150] During the process of the lifting device 4 lowering the filter cylinder 52 into the reaction cylinder 22, the lifting block 544 is sleeved on the lifting shaft 221 through the through hole. The lifting shaft 221 limits the lifting block 544, so that when the lifting device 4 continues to descend, the rotating shaft 532 separates from the U-shaped sleeve 543, thereby unlocking.

[0151] In this example, preferably, a spring can be fitted between the U-shaped sleeve 543 and the support block 541 to assist the U-shaped sleeve 543 in restoring itself to be fitted onto the rotating shaft 532 again.

[0152] Furthermore, the filter cartridge 52 is provided with an extension tube that is sleeved on the rotating shaft 532. A rubber sleeve is provided between the sleeve and the rotating shaft 532 to increase friction. When there is no solid material on the filter element 531, it will not rotate arbitrarily.

[0153] In another embodiment, the U-shaped sleeve 543 may be omitted, and a through hole may be opened on a rotating shaft 532, into which the bottom end of the connecting shaft 542 is inserted to limit its axial movement.

[0154] The working principle of the reaction device provided by this invention is as follows:

[0155] In use, the cathode carbon block to be reacted and sodium hydroxide are added into the reaction cylinder 22. Then, the lifting device 4 lowers the ultrasonic disperser 24 so that the ultrasonic probe of the ultrasonic disperser 24 enters the mixed solution in the reaction cylinder 22. The two materials react quickly through the ultrasonic cavitation effect. At the same time, the heating device 25 heats the mixed solution in the reaction cylinder 22 to the preset temperature.

[0156] After the reaction is completed, the rotating device 3 drives the mounting plate 21 to rotate by a preset angle so that the reaction cylinder 22 is aligned with the filter cylinder 52. At this time, the mounting plate 21 seals the top of the filter cylinder 52, and the discharge pipe of the reaction cylinder 22 is connected to the inside of the filter cylinder 52. The valve located on the discharge pipe is opened, and the solution inside the reaction cylinder 22 enters the filter cylinder 52 through the discharge pipe. The filtration structure 53 filters out the alkaline leaching residue in the solution, and the solution passes through the filtration structure 53 into the bottom cylinder 51.

[0157] After filtration, the rotating device 3 drives the mounting plate 21 to rotate in the opposite direction to its original position and separate it from the filtering device 5. Then, the filter cylinder 52 is separated from the bottom cylinder 51, and the filtered alkaline leaching residue is placed back into the filter cylinder 52. Then, hydrochloric acid solution is added into the filter cylinder 52 to carry out step S3. The reaction and filtration are carried out in the same way, so that the reaction of the mixed solution and solid-liquid separation can be realized quickly. The reaction between steps can be carried out quickly and continuously, improving the reaction efficiency.

[0158] The above description is merely an embodiment of the present invention and does not limit the patent scope of the present invention. Any equivalent structural or procedural transformations made based on the content of the present invention specification and drawings, or direct or indirect applications in other related technical fields, are similarly included within the patent protection scope of the present invention.

Claims

1. A method for preparing silicon carbide using cathode carbon blocks and coal gangue, characterized in that, Includes the following steps: S1: After crushing, grinding and sieving aluminum electrolytic cathode carbon blocks and silica-containing coal gangue, place them in an oven to dry for later use. S2: Using a reaction device, the dried cathode carbon block is mixed with sodium hydroxide solution, and after reacting with an ultrasonic power of 300~400W at a temperature of 60~75℃, the solid and liquid are separated to obtain alkaline leaching solution and alkaline leaching residue. S3: Use reaction equipment to mix the alkaline leaching residue and hydrochloric acid solution, react with 300~400W ultrasonic power at 60~75℃, and then separate the solid and liquid to obtain acid leaching solution and carbon powder; S4: Using a reaction device, dry coal gangue is mixed with hydrochloric acid solution, and reacted at 60-75℃ with an ultrasonic power of 300-400W. After solid-liquid separation, silicon dioxide is obtained. S5: Mix purified carbon powder and silica, add anhydrous ethanol as a surfactant, place in a planetary ball mill to ball mill to form a precursor, and then press the precursor into shape. S6: Place the pressed precursor in a corundum crucible, then place it in a tube furnace and heat it to 1500~1700℃ under argon atmosphere protection to obtain coarse SiC powder. S7: After mixing and reacting the obtained crude SiC powder with hydrofluoric acid, the mixture is filtered and dried to obtain the SiC product. The reaction apparatus includes: a support platform; The reaction structure includes a mounting plate, a reaction cylinder, an ultrasonic disperser, and a heating device. The mounting plate is rotatably mounted on the support, the reaction cylinder is mounted on the support, the discharge pipe of the reaction cylinder passes through the mounting plate, and the heating device is sleeved on the reaction cylinder. A lifting device, wherein the ultrasonic disperser is installed on the discharge pipe of the lifting device and aligned with the opening of the reaction cylinder; A filtration device is provided, wherein the filtration device and the reaction cylinder are set at a preset angle relative to the rotation center of the mounting plate. The filtration device includes a mounting frame, a bottom cylinder, a filter cylinder, and a filtration structure. The bottom cylinder is mounted on the mounting frame. The filter cylinder is detachably connected to the top of the bottom cylinder. The filtration structure is rotatably mounted inside the filter cylinder. A flange is provided inside the bottom cylinder to support the filtration structure. The rotating device is used to drive the mounting plate to rotate when performing solid-liquid separation on the material in the reaction cylinder.

2. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 1, characterized in that, In step S2, a 2-3 mol / L sodium hydroxide solution is used and mixed with the dried cathode carbon block at a solid-liquid ratio of 1:3 to 1:

4.

3. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 1, characterized in that, In step S3, a 2-3 mol / L hydrochloric acid solution is mixed with the alkaline leaching residue at a solid-liquid ratio of 1:3 to 1:

4.

4. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 1, characterized in that, In step S4, a 2-3 mol / L hydrochloric acid solution is mixed with the dried coal gangue at a solid-liquid ratio of 1:3 to 1:

4.

5. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 1, characterized in that, The rotating device includes a fixed plate, a motor, and a rotating column. The motor is mounted below the support through the fixed plate. The rotating column passes through the support and is rotatably connected to the support. The bottom end of the rotating column is fixedly connected to the motor. The lifting device is installed at the top of the rotating column, and the rotating column is detachably connected to the mounting plate via fittings.

6. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 5, characterized in that, The reaction structure also includes a cylinder cover, which is installed on the discharge pipe of the lifting device, and the ultrasonic disperser passes through the cylinder cover.

7. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 6, characterized in that, A drive block is installed on the rotating column, and an insertion hole is provided on the drive block. An assembly hole is provided on the mounting plate. The insertion hole and the assembly hole are concentrically arranged. The assembly is cylindrical and is installed on the discharge pipe of the lifting device and suspended above the insertion hole. When the lifting device drives the cylinder cover to seal the top of the reaction cylinder, the fitting passes through the insertion hole and the assembly hole in sequence; The cylinder cover is symmetrically equipped with mounting plates, and the mounting plates have mounting holes. Both sides of the filter cylinder are threaded with mounting pins. When the cylinder cover is rotated above the filter cylinder, the two mounting plates are aligned with the two mounting pins.

8. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 7, characterized in that, The filtration structure includes a filter element, a gear, and two rotating shafts. The two sides of the filter element are rotatably mounted inside the filter cartridge via corresponding rotating shafts. The gear is mounted on one of the rotating shafts and is located outside the filter cartridge. The inner wall of the reaction cylinder is equipped with a toothed plate. When the filter cylinder is suspended above the reaction cylinder, the toothed surface of the toothed plate is aligned with the gear.

9. The method for preparing silicon carbide using cathode carbon blocks and coal gangue according to claim 8, characterized in that, The filtration device also includes a positioning element for axially limiting the rotating shaft, and a lifting shaft is installed on the inner wall of the reaction cylinder above the toothed plate via a connecting block. When the filter cartridge is suspended above the reaction cylinder, the lifting shaft is aligned with the positioning member. During the process of the lifting device lowering the filter cartridge into the reaction cylinder, the lifting shaft interacts with the positioning member, causing the positioning member to unlock the rotating shaft.

Images