Resource utilization method of carbon residues in aluminum electrolysis cell

Abstract

The invention provides a resource utilization method of carbon residues in an aluminum electrolysis cell, and relates to the technical field of solid waste resource utilization. A resource utilization method of carbon residues in an aluminum electrolysis cell comprises the following steps that S1, the carbon residues in the aluminum electrolysis cell are smashed and screened and placed in a drying oven to be dried, then components are detected, and a dried material is obtained; s2, weighing the dried material and sodium carbonate, and performing mixing treatment to form a mixture; putting the mixture into a graphite crucible, simultaneously laying a layer of stone tar for flame retardance, putting the graphite crucible into a box-type resistance furnace, heating for reaction, and cooling to obtain mixed slag; and S3, mixing the mixed slag with deionized water. By constructing a green process route of reduction-harmlessness-high value of the carbon residues of the aluminum electrolysis cell, deep extraction and efficient utilization of valuable elements such as fluorine, sodium, aluminum and carbon are achieved, and the resource recovery rate is remarkably increased; valuable elements such as fluorine, sodium, aluminum and carbon in the carbon residues of the aluminum electrolysis cell can be effectively recycled, and cyclic utilization of resources is achieved.

Description

Technical Field

[0001] This invention relates to the field of solid waste resource utilization technology, and in particular to a method for the resource utilization of carbon slag in aluminum electrolysis cells. Background Technology

[0002] Aluminum electrolytic cell slag is a hazardous waste generated during aluminum industry production. Its composition is complex, containing large amounts of electrolytes (such as cryolite and sub-cryolite), alumina, and carbon materials. Traditional treatment methods primarily involve stockpiling, which not only wastes electrolyte resources but also causes environmental pollution. Therefore, the resource utilization of aluminum electrolytic cell slag is of great significance for environmental protection.

[0003] Traditional methods mainly employ flotation, but flotation suffers from incomplete carbon-electric separation, and direct roasting can easily generate secondary pollution. Further research is needed on how to effectively separate carbon and electrical components to improve the resource utilization of carbon slag from aluminum electrolysis cells.

[0004] Therefore, it is necessary to provide a method for the resource utilization of carbon slag in aluminum electrolysis cells to solve the above-mentioned technical problems. Summary of the Invention

[0005] This invention provides a method for the resource utilization of carbon slag in aluminum electrolytic cells, which solves the problem in related technologies that requires further research on how to effectively separate carbon and electrical components to improve the resource utilization of carbon slag in aluminum electrolytic cells.

[0006] To solve the above-mentioned technical problems, the present invention provides a method for the resource utilization of carbon slag in aluminum electrolysis cells, comprising the following steps:

[0007] Step S1: The carbon residue from the aluminum electrolysis cell is crushed, screened, dried in an oven, and its composition is tested to obtain the dried material;

[0008] Step S2: Weigh the dried material and sodium carbonate and mix them to form a mixture; put the mixture into a graphite crucible, and at the same time lay a layer of stone tar flame retardant, place it in a box-type resistance furnace, heat up to react, and obtain a mixed slag after cooling.

[0009] Step S3: Mix the mixed residue with deionized water, and add sulfuric acid to adjust the pH to 1-3. Place the mixture in a water bath and react at a constant temperature. Separate the solid and liquid to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder.

[0010] Step S4: Add sodium hydroxide to filtrate A, adjust the pH to 5.5-6.5, and place it in a water bath for constant temperature reaction. Filter to obtain residue B and filtrate B.

[0011] Step S5: Weigh filter residue B and mix it with water. Wash it three times to remove residual sodium salt. After washing and drying, transfer it to a muffle furnace for calcination. After cooling, solid aluminum fluoride is obtained.

[0012] Step S6: Transfer the filtrate B into an evaporating dish for evaporation and crystallization, filter to separate the crystals, and further dehydrate in an oven to obtain sodium sulfate.

[0013] Preferably, a jaw crusher is used for crushing in step S1.

[0014] Preferably, in step S1, the material is screened through a 150-200 mesh sieve.

[0015] Preferably, in step S2, the dried material and sodium carbonate are in a mass ratio of 1:1.5~2.5.

[0016] Preferably, in step S2, the reaction temperature is 650℃~750℃ and the reaction time is 2h~4h.

[0017] Preferably, the reaction temperature of the isothermal reaction in step S3 is 70℃~80℃, and the reaction time is 2h~3h.

[0018] Preferably, the reaction temperature of the isothermal reaction in step S4 is 70℃~80℃, and the reaction time is 2h~4h.

[0019] Preferably, in step S5, filter residue B is mixed with water at a solid-liquid ratio of 1:3 to 4.

[0020] Preferably, the calcination temperature in step S5 is 450℃~550℃, and the calcination time is 3h~7h.

[0021] Preferably, the evaporation and crystallization temperature in step S6 is 70°C to 80°C.

[0022] Compared with related technologies, the resource utilization method for carbon slag in aluminum electrolytic cells provided by this invention has the following beneficial effects:

[0023] By controlling the alkali melting temperature and holding time, the directional conversion of electrolyte components is achieved. A multi-stage solid-liquid separation technology of "alkali melting-acid leaching-alkali precipitation-calcination" is employed, significantly improving resource recovery rate. This constructs a green process route for "reduction-harmlessness-high value" of aluminum electrolytic cell slag, enabling deep extraction and efficient utilization of valuable elements such as fluorine, sodium, aluminum, and carbon, resulting in a significantly improved resource recovery rate. It can effectively recover valuable elements such as fluorine, sodium, aluminum, and carbon from aluminum electrolytic cell slag, achieving resource recycling. Attached Figure Description

[0024] 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.

[0025] Figure 1 A system diagram of the method for resource utilization of carbon slag in aluminum electrolytic cells provided by the present invention;

[0026] Figure 2 A three-dimensional view of the first embodiment of the box-type resistance furnace provided by the present invention;

[0027] Figure 3 for Figure 2 A three-dimensional view of a partial cross-section of the box-type resistance furnace shown.

[0028] Figure 4 for Figure 2 The diagram shows a cross-sectional view of the box-like structure. Figure 4 (a) in the middle is Figure 2 The diagram shows the structure of section AA. Figure 4 (b) in the middle is Figure 4 A magnified view of part (a) in the diagram;

[0029] Figure 5 for Figure 2 A schematic diagram of the cross-sectional section of BB shown;

[0030] Figure 6 for Figure 5 The diagram shows the structure of the heat-conducting plug in an avoidance state.

[0031] Figure 7 This is a schematic diagram of a first embodiment of the box-type resistance furnace provided by the present invention, wherein, Figure 7 (a) in the middle is Figure 6 The diagram shows the structure of the heat-conducting plug in an avoidance state. Figure 7 (b) shows the state diagram of the sealing plate in the unlocked mode. Figure 7 (c) in the diagram is the state diagram during the rotating plate switching process. Figure 7 (d) in the diagram represents the state after the rotating plate has switched rotations;

[0032] Figure 8 A three-dimensional view of a second embodiment of the box-type resistance furnace provided by the present invention;

[0033] Figure 9 for Figure 8 The diagram shows a cross-sectional view of the synchronizing rod connection structure.

[0034] Explanation of icon numbers:

[0035] 1. Enclosure; 11. Enclosure door; 12. Isolation panel; 13. Resistance heating chamber; 111. Lock; 120. Movable slot; 100. Heat treatment chamber; 200. Cooling chamber;

[0036] 2. Control cabinet;

[0037] 3. Heat conduction mechanism; 31. First telescopic component; 32. Heat conduction insert;

[0038] 4. Switching mechanism; 41. Rotating plate; 42. Driving component; 43. Bracket; 44. Assembly rack; 410. Locking groove;

[0039] 5. Graphite crucible;

[0040] 6. Purification box; 61. Fluid replacement tube; 62. Exhaust tube;

[0041] 7. Flow guide pipe; 71. Explosion ring;

[0042] 8. Adjustment component; 81. Second telescopic component; 82. Slide plate; 83. Sealing plate; 84. Transmission rod; 85. Locking pin;

[0043] 321. Synchronizing rod.

[0044] 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

[0045] 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.

[0046] This invention provides a method for the resource utilization of carbon slag in aluminum electrolysis cells.

[0047] Please see Figure 1 The method for resource utilization of carbon slag in the aluminum electrolytic cell in this invention includes the following steps:

[0048] Step S1: The carbon residue from the aluminum electrolysis cell is crushed, screened, dried in an oven, and its composition is tested to obtain the dried material;

[0049] Step S2: Weigh the dried material and sodium carbonate and mix them to form a mixture; put the mixture into a graphite crucible, and at the same time lay a layer of stone tar flame retardant, place it in a box-type resistance furnace, heat up to react, and obtain a mixed slag after cooling.

[0050] At high temperatures, the electrolyte in the carbon slag undergoes an alkaline fusion reaction with sodium carbonate, transforming into a soluble compound. The volatile gas is then oxidized and absorbed by a device containing sodium hypochlorite solution to remove harmful components.

[0051] Step S3: Mix the mixed residue with deionized water, and add sulfuric acid to adjust the pH to 1-3. Place the mixture in a water bath and react at a constant temperature. Separate the solid and liquid to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder.

[0052] Step S4: Add sodium hydroxide to filtrate A, adjust the pH to 5.5-6.5, and place it in a water bath for constant temperature reaction. Filter to obtain residue B and filtrate B.

[0053] Step S5: Weigh filter residue B and mix it with water. Wash it three times to remove residual sodium salt. After washing and drying, transfer it to a muffle furnace for calcination. After cooling, solid aluminum fluoride is obtained.

[0054] Step S6: Transfer the filtrate B into an evaporating dish for evaporation and crystallization, filter to separate the crystals, and further dehydrate in an oven to obtain sodium sulfate.

[0055] This method effectively treats carbon slag from aluminum electrolytic cells, achieving the harmless and resource-based utilization of the slag, while simultaneously producing high-purity aluminum fluoride products, reducing resource waste and environmental pollution.

[0056] Specifically, a jaw crusher is used for crushing in step S1.

[0057] Specifically, in step S1, the material is screened through a 150-200 mesh sieve.

[0058] Specifically, in step S2, the dried material and sodium carbonate are mixed in a mass ratio of 1:1.5~2.5.

[0059] Specifically, in step S2, the reaction temperature is 650℃~750℃ and the reaction time is 2h~4h.

[0060] Specifically, in step S3, the isothermal reaction temperature is 70℃~80℃, and the reaction time is 2h~3h.

[0061] Specifically, in step S4, the isothermal reaction temperature is 70℃~80℃, and the reaction time is 2h~4h.

[0062] Specifically, in step S5, filter residue B is mixed with water at a solid-liquid ratio of 1:3 to 4.

[0063] Specifically, in step S5, the calcination temperature is 450℃~550℃, and the calcination time is 3h~7h.

[0064] Specifically, the evaporation and crystallization temperature in step S6 is 70℃~80℃.

[0065] Based on the core technology of "alkali fusion directional conversion - multi-stage leaching separation - element cascade recovery", it has significant resource and environmental benefits and industrial application value.

[0066] Case 1:

[0067] Step S1: The carbon residue from the aluminum electrolysis cell is crushed by a jaw crusher, then sieved through a 150-mesh sieve and dried in an oven before its composition is tested for future use.

[0068] Step S2: Weigh the dried carbon slag and sodium carbonate and mix them evenly in a mass ratio of 1:2. Place the mixture in a graphite crucible and simultaneously lay a layer of stone tar flame retardant. Place it in a box-type resistance furnace and heat it to 700℃ for 2 hours. At high temperature, the electrolyte in the carbon slag undergoes an alkaline fusion reaction with the sodium carbonate, transforming into a soluble compound. The volatile gas is oxidized and absorbed by a device containing sodium hypochlorite solution to remove harmful components.

[0069] Step S3: After the calcined mixed residue is cooled, it is mixed with deionized water at a solid-liquid ratio of 1:3. At the same time, sulfuric acid is added to adjust the pH to 2. The mixture is placed in a water bath and reacted at 70°C for 3 hours. The solid and liquid are separated to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder.

[0070] Step S4: Add sodium hydroxide to filtrate A to adjust the pH to 5.5, and place it in a water bath at 70°C for 3 hours. Filter to obtain white aluminum hydroxy fluoride filter residue B and filtrate B.

[0071] Step S5: Weigh filter residue B and mix it with water at a solid-liquid ratio of 1:3. Wash the mixture three times to remove residual sodium salt. After washing and drying, transfer the mixture to a muffle furnace and calcine it at 500℃ for 3 hours. Cool the mixture to obtain solid aluminum fluoride.

[0072] Step S6: Transfer the filtrate B into an evaporating dish and evaporate and crystallize at 70°C. Filter to separate the crystals and further dehydrate in an oven to obtain sodium sulfate (sodium sulfate).

[0073] Case 2:

[0074] Step S1: The carbon residue from the aluminum electrolysis cell is crushed by a jaw crusher, then sieved through a 200-mesh sieve and dried in an oven before its composition is analyzed for future use.

[0075] Step S2: Weigh the dried carbon slag and sodium carbonate and mix them evenly at a mass ratio of 1:2.5. Place the mixture in a graphite crucible and simultaneously lay a layer of stone tar flame retardant. Place it in a box-type resistance furnace and heat it to 750℃ for 3 hours. At high temperature, the electrolyte in the carbon slag undergoes an alkaline fusion reaction with the sodium carbonate, transforming into a soluble compound. The volatile gas is oxidized and absorbed by a device containing sodium hypochlorite solution to remove harmful components.

[0076] Step S3: After the calcined mixed residue is cooled, it is mixed with deionized water at a solid-liquid ratio of 1:3.5. At the same time, sulfuric acid is added to adjust the pH to 1.5. The mixture is placed in a water bath and reacted at 80°C for 2 hours. The solid and liquid are separated to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder.

[0077] Step S4: Add sodium hydroxide to filtrate A to adjust the pH to 5.5, and place it in a water bath at 80°C for 2 hours. Filter to obtain white aluminum hydroxy fluoride filter residue B and filtrate B.

[0078] Step S5: Weigh filter residue B and mix it with water at a solid-liquid ratio of 1:4. Wash the mixture three times to remove residual sodium salt. After washing and drying, transfer the mixture to a muffle furnace and calcine it at 550°C for 3 hours. Cool the mixture to obtain solid aluminum fluoride.

[0079] Step S6: Transfer the filtrate B into an evaporating dish and evaporate and crystallize at 75°C. Filter to separate the crystals and further dehydrate in an oven to obtain sodium sulfate (sodium sulfate).

[0080] Case 3:

[0081] Step S1: The carbon slag from the aluminum electrolysis cell is crushed by a jaw crusher, then sieved through a 200-mesh sieve and dried in an oven before its composition is tested for future use.

[0082] Step S2: Weigh the dried carbon slag and sodium carbonate and mix them evenly at a mass ratio of 1:1.5. Place the mixture in a graphite crucible and simultaneously lay a layer of stone tar flame retardant. Place the crucible in a box-type resistance furnace and heat it to 650℃ for 4 hours. At high temperature, the electrolyte in the carbon slag undergoes an alkaline fusion reaction with the sodium carbonate, transforming into a soluble compound. The volatile gas is then oxidized and absorbed by a device containing sodium hypochlorite solution to remove harmful components.

[0083] Step S3: After the calcined mixed residue is cooled, it is mixed with deionized water at a solid-liquid ratio of 1:2.5. At the same time, sulfuric acid is added to adjust the pH to 1. The mixture is placed in a water bath and reacted at 70°C for 3 hours. The solid and liquid are separated to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder.

[0084] Step S4: Add sodium hydroxide to filtrate A to adjust the pH to 6.5, and react in a water bath at 75°C for 4 hours. Filter to obtain white aluminum hydroxy fluoride filter residue B and filtrate B.

[0085] Step S5: Weigh filter residue B and mix it with water at a solid-liquid ratio of 1:3. Wash the mixture three times to remove residual sodium salt. After washing and drying, transfer the mixture to a muffle furnace and calcine it at 450°C for 7 hours. Cool the mixture to obtain solid aluminum fluoride.

[0086] Step S6: Transfer the filtrate B into an evaporating dish and evaporate and crystallize at 80°C. Filter to separate the crystals and further dehydrate in an oven to obtain sodium sulfate (sodium nitrate).

[0087] Beneficial effects:

[0088] By controlling the alkali melting temperature and holding time, the directional conversion of electrolyte components is achieved. A multi-stage solid-liquid separation technology of "alkali melting-acid leaching-alkali precipitation-calcination" is employed, significantly improving resource recovery rate. This constructs a green process route for "reduction-harmlessness-high value" of aluminum electrolytic cell slag, enabling deep extraction and efficient utilization of valuable elements such as fluorine, sodium, aluminum, and carbon, resulting in a significantly improved resource recovery rate. It can effectively recover valuable elements such as fluorine, sodium, aluminum, and carbon from aluminum electrolytic cell slag, achieving resource recycling.

[0089] Case studies have shown that this process not only solves the environmental pollution risks caused by carbon slag stockpiling, but also optimizes the entire process cost and recycles resources through the reuse of by-product carbon powder and sodium sulfate recovery, significantly increasing the added value of solid waste resource utilization in the aluminum industry.

[0090] As an innovative technology solution for solid waste treatment in the electrolytic aluminum industry, it provides a replicable engineering paradigm for the large-scale treatment of similar hazardous wastes through precise parameter control and process integration innovation, and has broad industry application prospects and sustainable development significance.

[0091] The present invention also provides a box-type resistance furnace.

[0092] First embodiment.

[0093] Please refer to the following: Figures 2 to 5 In this invention, the box-type resistance furnace includes:

[0094] The box 1 is provided with a door 11. An isolation panel 12 is fixed inside the box 1, which divides the inside of the box 1 into a heat treatment chamber 100 and a cooling chamber 200. A resistance heating chamber 13 is fixed on the box 1 and is located within the heat treatment chamber 100. The opening of the resistance heating chamber 13 faces downward.

[0095] Control cabinet 2, which is mounted on the enclosure 1;

[0096] The switching mechanism 4 includes a rotating plate 41, a driving component 42, a bracket 43, and an assembly frame 44. The rotating plate 41 is rotatably mounted on the isolation enclosure 12. The fixed part of the driving component 42 is fixedly mounted on the housing 1. The driving shaft of the driving component 42 passes through the housing 1 and the isolation enclosure 12 and is fixedly connected to the rotating plate 41. The bracket 43 is fixedly mounted on the rotating plate 41. The assembly frame 44 is rotatably mounted on the bracket 43. Two sets of brackets 43 are provided, and the two sets of brackets 43 are respectively provided at the top and bottom of the rotating plate 41. The brackets 43 and the assembly frame 44 are arranged in a one-to-one correspondence.

[0097] Graphite crucible 5, the graphite crucible 5 is mounted on the assembly frame 44, and the graphite crucible 5 and the assembly frame 44 are arranged in a one-to-one correspondence;

[0098] The heat conduction mechanism 3 includes a first telescopic member 31 and a heat conduction plug 32. The fixed part of the first telescopic member 31 is fixedly disposed on the top of the housing 1. The telescopic part of the first telescopic member 31 passes through the housing 1 and the resistance heating chamber 13 and is fixedly connected to the heat conduction plug 32.

[0099] In this embodiment, the resistance heating chamber 13 adopts the heat treatment principle of a box-type resistance furnace in the prior art, mainly based on the resistance heating effect: when current passes through the heating element (such as resistance wire) in the furnace, electrical energy is converted into heat energy, causing the element to heat up. This heat is transferred to the workpiece in the furnace through radiation, conduction and convection, etc., to achieve uniform heating, which will not be elaborated on here.

[0100] In this embodiment, the use of the isolation plate 12 and the rotating plate 41 facilitates the separation of the heat treatment chamber 100 and the cooling chamber 200, so that while the graphite crucible 5 in the heat treatment chamber 100 is undergoing heat treatment, the graphite crucible 5 in the cooling chamber 200 can be cooled simultaneously.

[0101] The bottom of the heat-conducting insert 32 is provided with multiple insert shafts. When the insert shafts are inserted into the interior of the graphite crucible 5, they facilitate the transfer of heat energy to the material inside the graphite crucible 5, so as to ensure that the material is heated evenly.

[0102] The thermal conductive plug 32 has two usage states:

[0103] Avoidance situation, such as Figure 6 As shown, the heat-conducting plug 32 is separated from the graphite crucible 5, providing clearance space for the rotation adjustment of the rotating plate 41, the support 43, the assembly frame 44 and the graphite crucible 5;

[0104] Heating state, such as Figure 5As shown, the heat-conducting plug 32 is connected to the graphite crucible 5 to facilitate uniform heating of the material inside the graphite crucible 5 during heat treatment.

[0105] In this embodiment, the driving component 42 is a motor structure, used to directly drive the rotating plate 41 to rotate and adjust, so as to facilitate the switching of the two graphite crucibles 5 after installation.

[0106] In this embodiment, after the graphite crucible 5 is installed on the assembly frame 44, the center of gravity of the assembly frame 44 and the graphite crucible 5 as a whole is always located below the rotating shaft of the assembly frame 44. No matter how the rotating plate 41 is rotated and adjusted, the opening of the graphite crucible 5 is kept facing upwards to ensure the stability of the rotating plate 41 during the rotation switching process.

[0107] When the graphite crucible 5 is located within the heat treatment chamber 100, it is convenient to heat treat the material inside the graphite crucible 5.

[0108] When the graphite crucible 5 is located within the cooling chamber 200, it is convenient to cool the heat-treated graphite crucible 5 separately.

[0109] By providing mounting brackets 44 at both the top and bottom of the rotating plate 41, it is convenient to install two sets of graphite crucibles 5 simultaneously. While one graphite crucible 5 is undergoing heat treatment, the other graphite crucible 5 is being cooled, facilitating continuous operation of the equipment. During the cooling process of one graphite crucible 5, the resistance heating chamber 13 can continue to operate to heat treat the other graphite crucible 5 without needing to stop for cooling. This reduces the frequency of starting and stopping and adjusting the resistance heating chamber 13, facilitating continuous operation of the equipment, improving the efficiency of continuous heat treatment and cooling of materials, and saving energy and protecting the environment.

[0110] During the heat treatment process in the graphite crucible 5, the first telescopic member 31 facilitates the insertion of the heat-conducting plug 32 into the range of the graphite crucible 5, making the material in the graphite crucible 5 heat more evenly, improving the heat treatment efficiency, and ensuring the quality of the material heat treatment.

[0111] Please refer to the following: Figure 3 and Figure 5 The box-type resistance furnace also includes:

[0112] Purification box 6 is fixed on the housing 1 and located inside the control cabinet 2. The purification box 6 is provided with a liquid replacement pipe 61 and an exhaust pipe 62. The liquid replacement pipe 61 passes through the control cabinet 2 and extends to the outside of the control cabinet 2. The output end of the exhaust pipe 62 passes through the control cabinet 2 and extends to the outside of the control cabinet 2.

[0113] The guide pipe 7 has its input end passing through the purification box 6, the housing 1 and the resistance heating chamber 13 in sequence and extending into the heat treatment chamber 100. The output end of the guide pipe 7 is fixedly provided with an explosion ring 71, which is disposed in the purification box 6.

[0114] The input end of the guide pipe 7 is aligned with the lifting range of the heat-conducting plug 32, and the purification box 6 is filled with purification liquid, which completely submerges the explosion ring 71.

[0115] In this embodiment, the purification liquid can be a sodium hypochlorite solution, which is used to purify the exhaust gas generated during the heat treatment process, improve the exhaust quality, and is more environmentally friendly.

[0116] In this embodiment, the input end of the aeration ring 71 is connected to the output end of the guide pipe 7, and the output end of the aeration ring 71 is distributed in the bottom area of ​​the purification liquid, so that when the exhaust gas is discharged from the aeration ring 71, the exhaust gas can fully contact the purification liquid.

[0117] The guide pipe 7 facilitates the transfer of the exhaust gas generated during the operation of the heat treatment chamber 100 to the interior of the purification box 6, and the aeration ring 71 distributes the exhaust gas evenly within the range of the purification liquid, so that the exhaust gas and the purification liquid are in full contact, thereby improving the efficiency and quality of exhaust gas purification.

[0118] In this embodiment, the exhaust pipe 62 is used to discharge the purified exhaust gas.

[0119] The fluid replacement pipe 61 is used to discharge and replace the purified liquid in the purification box 6. The fluid replacement pipe 61 is equipped with an independent control valve to facilitate the opening and closing control of the fluid replacement pipe 61.

[0120] Since the input end of the guide tube 7 is aligned with the lifting range of the heat-conducting plug 32, when the heat-conducting plug 32 switches to the avoidance state, the top of the heat-conducting plug 32 can also block and close the input end of the guide tube 7 to reduce heat loss when the rotating plate 41 is rotated and adjusted.

[0121] In a preferred embodiment of this example, an air pump (not shown) is also provided at the input end of the exhaust pipe 62 for actively extracting the exhaust gas from the heat treatment chamber 100 through the guide pipe 7.

[0122] Please refer to the following: Figure 3 and Figure 4The box-type resistance furnace is further provided with a latch 111 fixed on the door 11, two movable grooves 120 are opened on the isolation enclosure 12, and two locking grooves 410 are opened on the rotating plate 41; the box-type resistance furnace also includes an adjustment component 8, which includes a second telescopic member 81, a sliding plate 82, a sealing plate 83, a transmission rod 84, and a locking pin 85. The fixed part of the second telescopic member 81 is fixedly installed in the box body 1, the sliding plate 82 is slidably installed in the box body 1, the bottom of the sliding plate 82 is fixedly connected to the telescopic part of the second telescopic member 81, the sealing plate 83 passes through the movable groove 120 and is slidably installed on the isolation enclosure 12, the two ends of the transmission rod 84 are respectively hinged to the sliding plate 82 and the sealing plate 83, and the locking pin 85 is fixedly installed on the sliding plate 82. The number of movable grooves 120, locking grooves 410, sealing plates 83, and transmission rods 84 are equal, and the four are arranged in a one-to-one correspondence.

[0123] When the sealing plate 83 is inserted into the locking groove 410, the locking pin 85 separates from the latch 111; when the sealing plate 83 is disengaged from the locking groove 410, the locking pin 85 engages with the latch 111.

[0124] In an optional embodiment of this example, the second telescopic member 81 may be a hydraulic telescopic cylinder, used to directly drive the sliding plate 82 to adjust its height within the cooling chamber 200.

[0125] In this embodiment, the sealing plate 83 includes two operating modes:

[0126] In the sealed locking mode, the sealing plate 83 is fully inserted into the locking groove 410, so that the connection between the rotating plate 41 and the isolation enclosure 12 is sealed and locked, reducing the flow of heat from the heat treatment chamber 100 to the cooling chamber 200 during operation; at the same time, the locking pin 85 is separated from the latch 111, so that the door 11 can be opened to discharge the material after the material in the cooling chamber 200 has been cooled.

[0127] In the unlocking mode, the sealing plate 83 is completely pulled out of the locking groove 410, thereby unlocking the rotating plate 41 from the isolation plate 12, facilitating stable rotation adjustment of the rotating plate 41; at the same time, the locking pin 85 is inserted into the latch 111 to ensure the stability of the closed state of the box door 11 (the box door 11 cannot be opened).

[0128] The second telescopic component 81 facilitates the control of the lifting and adjustment of the slide plate 82, and the slide plate 82 controls the sealing plate 83 to switch modes via the transmission rod 84.

[0129] During the process of the sealing plate 83 switching from the unlocking mode to the sealing locking mode, the sliding plate 82 also simultaneously drives the locking pin 85 to separate from the latch 111, so as to facilitate the stable discharge of the material after cooling in the cooling chamber 200;

[0130] When the sealing plate 83 switches from the sealing and locking mode to the unlocking mode, the sliding plate 82 also simultaneously drives the locking pin 85 to engage and lock with the latch 111, so as to lock the box door 11 before the rotating plate 41 rotates and switches, ensuring the stability of the rotating plate 41 driving the two graphite crucibles 5 to rotate and switch, preventing the box door 11 from being opened and causing a safety accident, and ensuring the safety of the equipment during operation.

[0131] The working principle of the box-type resistance furnace provided in this embodiment is as follows:

[0132] Let's define it as follows: In the initial state, the graphite crucibles 5 are pre-assembled on the two assembly racks 44, such as... Figure 7 As shown in (a), the graphite crucible 5 in the heat treatment chamber 100 is defined as crucible I; the graphite crucible 5 in the cooling chamber 200 is defined as crucible II, and both crucibles are filled with materials that need to be heat treated.

[0133] like Figure 4 As shown in (a), when the equipment is running, the sealing plate 83 is in the sealing and locking mode, the heat-conducting plug 32 is in the heating state, the resistance heating chamber 13 is activated, the temperature of the heat treatment chamber 100 rises, and the material is heat-treated.

[0134] See also Figures 5 to 6 and Figure 4 (a) to Figure 7 In (a), after the material in crucible I has been heat-treated, the first telescopic component 31 is activated. The first telescopic component 31 drives the heat-conducting plug 32 to move upward. The heat-conducting plug 32 is pulled out from the range of crucible I until the top of the heat-conducting plug 32 blocks the input end of the guide pipe 7.

[0135] So that the inlet of the flow guide tube 7 can be closed simultaneously during the process of the heat-conducting plug 32 switching from the heating state to the avoidance state;

[0136] On the one hand, it provides clearance for the rotation of the rotating plate 41, and on the other hand, it reduces heat loss during the switching process;

[0137] See also Figure 7 (a) to Figure 7In (b), before switching between the two crucibles, the second telescopic component 81 is activated first. The second telescopic component 81 drives the slide plate 82 to move upward. On the one hand, the slide plate 82 pushes the sealing plate 83 to slide through the transmission rod 84 and is pulled out from the range of the locking groove 410, so that the rotating plate 41 is unlocked.

[0138] On the other hand, the sliding plate 82 drives the locking pin 85 to move upward, and the locking pin 85 moves upward and inserts into the locking range of the latch 111, thereby locking the box door 11 and preventing the box door 11 from opening during the rotation and switching of the rotating plate 41;

[0139] So that the door 11 can be locked simultaneously during the process of the sealing plate 83 switching from the sealing locking mode to the unlocking mode;

[0140] See also Figure 7 (b) to Figure 7 (c) to Figure 7 In (d), when switching between the two crucibles, the drive unit 42 is activated, and the drive unit 42 drives the rotating plate 41 to rotate clockwise (e.g., Figure 7 (in the direction shown), the rotating plate 41 drives the two sets of supports 43, the assembly frame 44 and the graphite crucible 5 to rotate, so that crucible I rotates from the heat treatment chamber 100 to the cooling chamber 200, and crucible II rotates from the cooling chamber 200 to the heat treatment chamber 100.

[0141] This allows for switching between the two graphite crucibles 5 after the rotating plate 41 is unlocked.

[0142] When crucible II is heat-treated, crucible I is cooled, and the two do not interfere with each other. Then, the second telescopic component 81 controls the locking between the sealing plate 83 and the rotating plate 41. At the same time, the locking pin 85 separates from the latch 111 so that after crucible I is cooled, the box door 11 can be opened and the discharge material can be taken out.

[0143] Second embodiment:

[0144] Referring to Figure *, based on the box-type resistance furnace provided in the first embodiment of the present invention, the second embodiment of the present invention proposes another box-type resistance furnace. 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.

[0145] Specifically, the difference in the box-type resistance furnace provided in the second embodiment of the present invention is that the second telescopic member 81 may not be a hydraulic telescopic cylinder.

[0146] The second telescopic component 81 is a spring-supported tube, and the second telescopic component 81 elastically connects the box body 1 and the slide plate 82;

[0147] A synchronizing rod 321 is fixed on the heat-conducting plug 32. The synchronizing rod 321 has an L-shaped structure. The bottom of the synchronizing rod 321 passes through the isolation enclosure 12 and abuts against the top of the sliding plate 82.

[0148] In this embodiment, when the heat-conducting plug 32 is in a heating state, the bottom of the synchronizing rod 321 abuts against the top of the sliding plate 82 to control the sealing plate 83 to remain in a sealing and locking mode.

[0149] When the heat-conducting plug 32 is in the avoidance state, the bottom of the synchronizing rod 321 separates from the top of the slide plate 82, and the second telescopic member 81 adaptively controls the slide plate 82 to move upward, thereby controlling the sealing plate 83 to maintain the unlocked mode.

[0150] By abutting the synchronizing rod 321 against the sliding plate 82, the sliding plate 82 is synchronously controlled to move downward when the heat-conducting plug 32 is inserted into the graphite crucible 5, so that the sealing plate 83 is stably inserted into the range of the locking groove 410, so as to maintain the stability during operation in the heat treatment chamber 100 and reduce the loss of temperature.

[0151] When the heat-conducting plug 32 separates from the graphite crucible 5, the heat-conducting plug 32 synchronously drives the synchronizing rod 321 to move upward. The synchronizing rod 321 moves upward and separates from the sliding plate 82. The second telescopic member 81 adaptively pushes the sliding plate 82 upward, so that during the process of the heat-conducting plug 32 switching from the heating state to the avoidance mode, the sealing plate 83 simultaneously switches from the sealing and locking mode to the unlocking mode.

[0152] So that under the driving action of the first telescopic member 31, the state switching of the heat-conducting plug 32, the mode switching of the sealing plate 83, and the opening and closing of the box door 11 can be realized simultaneously.

[0153] The working principle of the box-type resistance furnace provided in this embodiment is as follows:

[0154] B1. During heat treatment, the heat-conducting insert 32 is in a heating state and the sealing plate 83 is in a sealed and locked state to ensure the stability of the material in the heat treatment chamber 100 during heat treatment.

[0155] B2, after the material in the heat treatment chamber 100 has been heat-treated, the first telescopic component 31 is activated first. The first telescopic component 31 drives the heat-conducting plug 32 to switch from the heating state to the avoidance state, so that the heat-conducting plug 32 is separated from the graphite crucible 5.

[0156] During the upward movement of the heat-conducting insert 32, the heat-conducting insert 32 also drives the synchronizing rod 321 to move upward. The synchronizing rod 321 separates from the top of the slide plate 82. At the same time, the second telescopic member 81 adaptively pushes the slide plate 82 upward. During the upward movement of the slide plate 82, the transmission rod 84 synchronously drives the slide plate 82 to retract and separate from the locking groove 410, thereby unlocking the rotating plate 41 and facilitating the subsequent rotation adjustment of the rotating plate 41.

[0157] At the same time, the sliding plate 82 also drives the locking pin 85 to move upward, so that the locking pin 85 and the latch 111 are engaged and locked, thereby locking and limiting the door 11, so that the door 11 cannot be opened during the rotation of the rotating plate 41, ensuring the safety of the equipment during operation.

[0158] B3, crucible switching, start the drive unit 42, the drive unit 42 drives the rotating plate 41 to rotate, so as to control the two graphite crucibles 5 to switch positions;

[0159] B4, the equipment is reset. The heat-conducting plug 32 is reset to the heating state by controlling the first telescopic component 31. At the same time, the heat-conducting plug 32 drives the slide plate 82 to move down through the synchronous rod 321, so that the sealing plate 83 switches from the sealing and locking mode to the unlocking mode, and the box door 11 is unlocked.

[0160] 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 the resource utilization of carbon slag in aluminum electrolytic cells, characterized in that, Includes the following steps: Step S1: The carbon residue from the aluminum electrolysis cell is crushed, screened, dried in an oven, and its composition is tested to obtain the dried material; Step S2: Weigh the dried material and sodium carbonate and mix them to form a mixture; put the mixture into a graphite crucible, and at the same time lay a layer of stone tar flame retardant, place it in a box-type resistance furnace, heat up to react, and obtain a mixed slag after cooling. Step S3: Mix the mixed residue with deionized water, and add sulfuric acid to adjust the pH to 1-3. Place the mixture in a water bath and react at a constant temperature. Separate the solid and liquid to obtain filter residue A and filtrate A. Filter residue A is washed with water and dried to make carbon powder. Step S4: Add sodium hydroxide to filtrate A, adjust the pH to 5.5-6.5, and place it in a water bath for constant temperature reaction. Filter to obtain residue B and filtrate B. Step S5: Weigh filter residue B and mix it with water. Wash it three times to remove residual sodium salt. After washing and drying, transfer it to a muffle furnace for calcination. After cooling, solid aluminum fluoride is obtained. Step S6: Transfer the filtrate B into an evaporating dish for evaporation and crystallization, filter to separate the crystals, and further dehydrate in an oven to obtain sodium sulfate.

2. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, In step S1, a jaw crusher is used for crushing.

3. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, In step S1, the material is screened through a 150-200 mesh sieve.

4. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, In step S2, the dried material and sodium carbonate are mixed in a mass ratio of 1:1.5~2.

5.

5. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, In step S2, the reaction temperature is 650℃~750℃ and the reaction time is 2h~4h.

6. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, The isothermal reaction in step S3 is at a temperature of 70℃~80℃ and a reaction time of 2h~3h.

7. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, The isothermal reaction in step S4 is at a temperature of 70℃~80℃ and a reaction time of 2h~4h.

8. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, In step S5, filter residue B is mixed with water at a solid-liquid ratio of 1:3 to 4.

9. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, The calcination temperature in step S5 is 450℃~550℃, and the calcination time is 3h~7h.

10. The method for resource utilization of carbon slag in aluminum electrolytic cells according to claim 1, characterized in that, The evaporation and crystallization temperature in step S6 is 70℃~80℃.

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