Method for preparing battery-grade lithium carbonate by recycling aluminum electrolysis waste residues

Abstract

The invention discloses a method for preparing battery-grade lithium carbonate by recycling aluminum electrolysis waste residues, and belongs to the technical field of electrolytic aluminum waste residue treatment.The method comprises the following steps that a lithium-containing intermediate material is pulpified and ball-milled, wet dissolution is facilitated, a reactant alpha is obtained, the reactant alpha is conveyed into a hot acid reaction device, lithium is leached out through sulfuric acid, and lithium carbonate is obtained; lithium is leached into the solution, and lithium-containing leaching liquid is obtained through filtering; according to the method, the lithium-containing intermediate material can be treated through fine control steps, lithium is efficiently extracted, impurities are removed, the purity and quality of the product are ensured, meanwhile, the environmental protection property is considered, the reaction activity of the material is improved through roasting, the lithium leaching rate is increased, the pH value is adjusted through a chemical reagent, and the lithium sulfate solution is purified; on the other hand, slurry and reaction materials are efficiently mixed through a hot acid reaction device and a multi-layer mixing technology, the lithium leaching rate and the recovery efficiency are improved, and energy utilization is optimized through an external hot blast stove and a waste heat recovery system.

Description

Technical Field

[0001] The invention relates to the technical field of aluminum electrolysis waste slag treatment, and specifically to a method for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate. Background Art

[0002] With the rapid development of the electrolytic aluminum industry, the power lithium battery industry has also shown explosive growth, and the demand for lithium carbonate has also increased year by year. As strategic resources in the 21st century, metallic lithium and lithium salts are widely used in the battery industry, glass and ceramics industry, lubricants, refrigerants, nuclear industry, optoelectronics industry and other fields. The traditional raw materials for making lithium carbonate are mainly divided into lithium mines and salt lakes. However, the magnesium content in salt lakes is high, and the lithium extraction technology is difficult. In addition, domestic salt lakes are mostly distributed in western plateau areas such as Qinghai and Tibet, with poor natural conditions and a shortage of technical personnel. The output of domestic lithium ore resources is limited, and the dependence on imports is high. The shortage of raw materials has led to a low capacity exchange rate for some domestic lithium carbonate companies. Using lithium-containing intermediate materials and concentrated sulfuric acid as raw materials, through a series of process processes such as acid leaching extraction, to prepare battery-grade lithium carbonate is a channel for recycling lithium salt products and maximizing production efficiency.

[0003] In conjunction with the above content, it should be explained that: Chinese patent with announcement number CN115893462A discloses a method and equipment for recovering electrolytic aluminum waste slag, which recovers lithium carbonate and other substances in electrolytic aluminum one by one through an improved method and multiple sets of linked coordinated devices. However, during actual use, the slurry prepared from electrolytic aluminum waste slag is mixed with concentrated sulfuric acid for acid leaching, which is an important step. During the reaction, it is easily disturbed by various factors, such as material mixing, reaction time, temperature and other factors, resulting in differences in the reaction of the slurry with concentrated sulfuric acid, resulting in large differences in reaction rate and output.

[0004] A Chinese patent with announcement number CN117344139A discloses a method for extracting lithium from electrolytic aluminum solid waste. Although the amount of leaching additives is reduced, the amount of acidic leaching agents is reduced, the lithium solution is purified, and the process is clean and pollution-free, the reduction in the amount of leaching additives further increases the mixing reaction efficiency and yield between the leaching additives and the slurry, thereby increasing the overall processing time consumption, and the extension of the reaction time is easily accompanied by the adhesion of precipitates and other related adverse factors.

[0005] In view of the above technical defects, a solution is now proposed. Summary of the invention

[0006] The purpose of the present invention is to provide a method for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate, so as to solve the problems raised in the background.

[0007] To achieve the above object, the present invention provides the following technical solution: a method for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate, comprising the following steps:

[0008] S1. Slurrying and ball-milling the lithium-containing intermediate material for wet dissolution to obtain reactant α;

[0009] S2. The reactant α is transported into a hot acid reaction device, lithium is leached with sulfuric acid, lithium is leached into the solution, and a lithium-containing leachate is obtained by filtering;

[0010] S3. Calcium hydroxide is added to adjust the pH value, purify and remove impurities, filter, and treat the lithium-containing solution to obtain a high-purity reactant β;

[0011] S4. Add trisodium phosphate into the high-purity reactant β to precipitate lithium, centrifuge and filter, then dissolve with sulfuric acid;

[0012] S5. Add calcium hydroxide, adjust the value and remove impurities;

[0013] S6. Using sodium carbonate to precipitate lithium, filtering to obtain lithium carbonate, evaporating and concentrating, and crystallizing lithium carbonate to obtain a product;

[0014] S7. In the electric carbon process of the lithium recovery workshop, industrial lithium carbonate is dissolved, impurity-removed, decolorized, lithium precipitated and evaporated to produce battery-grade lithium carbonate.

[0015] The present invention also proposes a thermal acid reaction device for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate. The thermal acid reaction device includes a limiting base and a circulating furnace body. The circulating furnace body is provided with an upper cone and a lower cone. A grading spray rack inserted into the lower cone is provided on the top of the limiting base. A spray cone disc is provided on the top of the grading spray rack. A middle cylinder is provided between the lower cone and the upper cone.

[0016] Furthermore, a conical spray rack and a straight spray port are arranged inside the middle cylinder, a diversion top cover is arranged on the top of the upper cone, a downward pressure hydraulic cylinder is arranged through the top of the diversion top cover, and a pressure plate extending to the inside of the upper cone is arranged at the bottom of the downward pressure hydraulic cylinder.

[0017] Furthermore, inner cones are provided inside the lower cone and the upper cone, and conical spiral cavities are provided between the inner cone, the lower cone and the upper cone. An air guide valve is provided at the bottom of the lower cone, and an air return pipe rack is provided on the outer wall of the upper cone.

[0018] Furthermore, a telescopic cylinder column is sleeved in the middle of the graded spray rack, and a top cone is provided on the top of the telescopic cylinder column. A guide groove connected to the spray cone disc is provided on the surface of the telescopic cylinder column. A traction pipe connected to the spray cone disc is penetrated through the top surface of the graded spray rack, and an inner groove is provided at the bottom of the spray cone disc.

[0019] Furthermore, a straight cylinder is arranged inside the middle cylinder, and a threaded cavity is arranged between the straight cylinder and the middle cylinder, and the conical spray rack is fixed on the inner wall of the top of the straight cylinder.

[0020] Furthermore, a straight nozzle is arranged on the inner wall of the top of the conical spray rack, a material injection pipe groove penetrating the straight tube and the middle tube is arranged on one side of the conical spray rack, and a reinforcing hoop is arranged on the outer periphery of the middle tube.

[0021] Furthermore, an exhaust valve is provided through the center of the top of the diverter cover, an inner air collecting groove connecting the upper cone and the exhaust valve is provided at the center of the bottom of the diverter cover, and an outer air collecting groove is provided at the bottom edge of the diverter cover.

[0022] Furthermore, an outer cone sleeve is provided on the outer periphery of the pressure plate, a multi-layer annular chamber is provided inside the pressure plate, a mixing flow chamber penetrating the annular chamber is provided at the bottom of the pressure plate, and a plurality of groups of positive spiral plates and reverse spiral plates are provided on the inner wall of the mixing flow chamber.

[0023] The beneficial effects of the present invention are:

[0024] 1. The present invention is a process for recovering lithium by processing lithium-containing intermediate materials. Through a series of finely controlled steps, not only lithium resources can be efficiently extracted, but also impurities can be effectively removed to ensure the purity and quality of the final product, while taking environmental protection requirements into account. The reaction activity of the material is improved through roasting pretreatment, so that the leaching rate of lithium in the subsequent wet leaching process is significantly improved, and the efficiency of the overall process is improved. In the value adjustment and purification and impurity removal stages, chemical reagents such as calcium hydroxide and sodium hydroxide are added to accurately control the pH value, effectively remove impurities such as fluorine, and further purify the lithium sulfate solution, laying a foundation for the subsequent preparation of high-purity lithium carbonate.

[0025] 2. The present invention uses a hot acid reaction device to carefully mix and formulate the wetted slurry and reaction materials, and realizes efficient mixing of the slurry and reaction materials through the slurry rain curtain with a double-layer fixed flow trajectory and the suspended spraying of the spray cone disc, which not only increases the contact area, but also promotes the full reaction between the materials, improves the lithium leaching rate and recovery efficiency, and realizes multi-stage mixing and enhanced reaction of the mixture through the step-by-step matching extrusion of the pressure plate and the inner cone, the static mixing structure, the single extrusion mixing and the falling mixing, which significantly improves the uniformity and reaction rate of the mixture, and provides a strong guarantee for the preparation of high-purity lithium carbonate.

[0026] 3. The present invention realizes preheating and temperature balance control inside the circulating furnace body by utilizing an external hot blast furnace and a conical spiral cavity structure. The internal heating method reduces temperature spillover, improves energy utilization efficiency, and ensures the stability of the reaction process. At the same time, through the waste heat recovery system, the heat in the hot gas is utilized in multiple stages to further reduce energy consumption. In combination with the entire process, environmental protection measures are emphasized. Through devices such as waste gas absorption towers and alkali spray acid mist absorption towers, waste gas generated in the process is effectively captured and treated to ensure that the waste gas meets emission standards. This not only protects the ecological environment, but also ensures the compliance and ecological nature of the electrolytic aluminum waste slag recovery process. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0028] Figure 1 The lithium-containing material processing process flow chart of the present invention;

[0029] Figure 2 It is a schematic diagram of the overall cross-sectional structure of the thermal acid reaction device of the present invention;

[0030] Figure 3 It is a schematic diagram of the three-dimensional structure of the thermal acid reaction device of the present invention;

[0031] Figure 4 It is a structural schematic diagram of the lower cone of the present invention;

[0032] Figure 5 It is a structural schematic diagram of the graded spray rack of the present invention;

[0033] Figure 6 It is a bottom view structural schematic diagram of the upper cone of the present invention;

[0034] Figure 7 It is a schematic cross-sectional structure diagram of the middle tube of the present invention;

[0035] Figure 8 It is a schematic diagram of the connection structure between the diverter top cover and the downward pressure hydraulic cylinder of the present invention;

[0036] Fig. 9 It is a structural schematic diagram of the downward pressure hydraulic cylinder of the present invention.

[0037] Figure numerals: 1. limit base; 2. circulating furnace body; 201. lower cone; 202. upper cone; 203. inner cone; 204. air guide valve; 205. return air pipe rack; 206. conical spiral chamber; 3. diversion top cover; 301. exhaust valve; 302. outer gas collecting tank; 303. inner gas collecting tank; 4. graded spray rack; 401. spray cone disc; 402. top cone; 403. traction pipe; 404. inner groove; 405. telescopic cylinder column; 5. middle cylinder; 501. threaded chamber; 502. conical spray rack; 503. reinforcement hoop; 504. injection pipe groove; 505. straight nozzle; 506. straight cylinder; 6. downward pressure hydraulic cylinder; 601. pressure plate; 602. outer cone sleeve; 603. mixed flow chamber; 604. ring warehouse. DETAILED DESCRIPTION

[0038] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0039] Example 1: Please refer to Figure 1 As shown, this embodiment is a method for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate, comprising the following steps:

[0040] S1. The lithium-containing intermediate material is slurried and ball-milled for wet dissolution. The lithium-containing intermediate material is first ball-milled into a 200-mesh powder to prepare for subsequent roasting and facilitate wet dissolution. The powder is added to a rotary kiln and roasted at 600°C. The roasted material enters a slurry tank through a discharge screw, and recycled water and washing water are added for stirring and slurrying to obtain a reactant α, which is helpful for subsequent wet dissolution of lithium.

[0041] S2. The reactant α is transported into the hot acid reaction device, and the lithium is leached with sulfuric acid. The lithium is leached into the solution, and the lithium-containing leaching solution is obtained by filtering. The filter residue is the leaching residue. The leaching temperature is 85°C. The reaction equation is: 2Li + +H2SO4→Li2SO4+2H + .

[0042] S3. Add calcium oxide or calcium hydroxide to adjust the pH value and remove fluorine. The reaction equation is: 2NaF + Ca (OH) 2 → 2NaOH + CaF2 ↓. After filtration, the calcium fluoride slag is used together with the subsequent impurity removal slag as the impurity removal slag, and the filtrate enters the purification process;

[0043] S4. Add trisodium phosphate into the high-purity reactant β to precipitate lithium, centrifuge and filter, then dissolve with sulfuric acid;

[0044] S5. Adding sodium hydroxide to the lithium-containing solution for further impurity removal and purification to obtain a purified lithium sulfate solution;

[0045] S6. First, the purified lithium sulfate solution is evaporated and concentrated to increase the lithium concentration, and then sodium carbonate is used to precipitate lithium. The reaction equation is: Li2SO4+Na2CO3→Na2SO4+Li2CO3↓, and crude lithium carbonate is obtained by filtration;

[0046] S7. In the electrocarbon process of the lithium recovery workshop, crude lithium carbonate is dissolved, purified, impurity-removed, decolorized, evaporated and crystallized to produce battery-grade lithium carbonate.

[0047] Example 2: Please refer to Figure 2 - Figure 5As shown, this embodiment is a thermal acid reaction device for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate. The thermal acid reaction device includes a limiting base 1 and a circulating furnace body 2. The circulating furnace body 2 is provided with an upper cone 201 and a lower cone 202. A grading spray rack 4 inserted into the lower cone 201 is provided on the top of the limiting base 1. A spray cone disc 401 is provided on the top of the grading spray rack 4. A middle cylinder 5 is provided between the lower cone 201 and the upper cone 202.

[0048] The lower cone 201 and the upper cone 202 are both provided with inner cones 203, and a conical spiral cavity 206 is provided between the inner cone 203 and the lower cone 201 and the upper cone 202. An air guide valve 204 is provided at the bottom of the lower cone 201, and a return air pipe rack 205 is provided on the outer wall of the upper cone 202. Before the slurry and the reaction material enter the hot acid reaction device, the hot air is blown into the conical spiral cavity 206 along the air guide valve 204 through the external hot air furnace, and then blown into the conical spiral cavity 206 along the air guide valve 204. The conical spiral chamber 206 of the lower cone 201 enters the threaded chamber 501 of the middle cylinder 5, and then enters the conical spiral chamber 206 of the upper cone 202, and finally gathers in the outer gas collecting groove 302. During this process, the heat in the hot gas is absorbed by the partition formed by the conical spiral chamber 206 and the threaded chamber 501, the inner cone cylinder 203 and the straight cylinder 506, and then transferred to the interior of the circulation furnace body 2, so as to preheat the interior of the circulation furnace body 2 in advance and keep the temperature of each area balanced after continuous injection of the circulation furnace body 2.

[0049] The return air pipe rack 205 is connected to the external air collecting tank 302 to centrally reflux the hot air that has absorbed heat, which is convenient for low-energy circulation heating treatment of the hot blast furnace. The hot air temperature is 250-300°C, and there is no open flame. The material is directly heated to form an internal heating method for the circulating furnace body 2, which reduces temperature overflow and maintains the temperature of each area inside the circulating furnace body 2 balanced. During the period when the return air pipe rack 205 guides the reflux of the waste heat, the metal pipe runs through the middle of the return air pipe rack 205, so that the slurry pushed by the spiral conveyor frame can be preheated in advance before entering the circulating furnace body 2, and the waste heat can be utilized at multiple levels.

[0050] A telescopic cylinder column 405 is sleeved in the middle of the graded spray rack 4, and a top cone 402 is provided on the top of the telescopic cylinder column 405. A guide groove connected to the spray cone disc 401 is provided on the surface of the telescopic cylinder column 405. A traction pipe 403 connected to the spray cone disc 401 is penetrated through the top surface of the graded spray rack 4, and an inner groove 404 is provided at the bottom of the spray cone disc 401.

[0051] The telescopic cylinder column 405 is telescopically extended and expanded by being driven by an external driving element, and the telescopic cylinder column 405 drives the top cone 402 and the spray cone disc 401 to slide upward. During this period, multiple groups of spray cone discs 401 are affected by the traction tube 403 and the length limit of the guide groove, and are thus limited in a fixed area during the upward sliding of the telescopic cylinder column 405. The spray cone disc 401 slides with the guide groove on the surface of the telescopic cylinder column 405, and is affected by the telescopic cylinder column 405 and hovers in this area. A spring damper connected to the inner wall of the graded spray rack 4 is provided on the surface of the traction tube 403, and as the telescopic cylinder column 405 continues to slide upward, multiple groups of spray cone discs 401 are limited and hovered in turn.

[0052] The external feeding equipment is connected to the traction tube 403 from the limiting base 1, and the reaction material is transported along the traction tube 403 into the multiple groups of spray cone discs 401. The reaction material is sprayed outward along the fine holes opened on the top surface of the spray cone disc 401. Affected by the hovering position of the multiple groups of spray cone discs 401, the sprayed reaction material is contacted and mixed with the conical slurry rain curtain and the secondary slurry rain curtain in the air in the top area of ​​the lower cone 201, and the slurry and reaction material fall to the bottom of the lower cone 201 due to their own weight, and contact with the inner wall of the inner cone 203 to form secondary mixing. The slurry and reaction material continue to fall, and tertiary mixing is achieved to accelerate the hot acid treatment.

[0053] Example 3: Please refer to Figure 2 , Figure 6 - Fig. 9 As shown, this embodiment is a thermal acid reaction device for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate, including a conical spray rack 502 and a straight nozzle 505 arranged inside a middle cylinder 5, a diverter top cover 3 is arranged on the top of the upper cone 202, a downward pressure hydraulic cylinder 6 is arranged through the top of the diverter top cover 3, and a pressure plate 601 extending to the interior of the upper cone 202 is arranged at the bottom of the downward pressure hydraulic cylinder 6.

[0054] A straight cylinder 506 is arranged inside the middle cylinder 5 , and a threaded cavity 501 is arranged between the straight cylinder 506 and the middle cylinder 5 . The conical spray rack 502 is fixed on the inner wall of the top of the straight cylinder 506 .

[0055] A straight nozzle 505 is provided on the inner wall of the top of the conical spray rack 502, and an injection pipe groove 504 that penetrates the straight cylinder 506 and the middle cylinder 5 is provided on one side of the conical spray rack 502. When the aluminum electrolysis waste slag is ground into slurry, one end of the spiral conveyor frame is inserted into the injection pipe groove 504 through a metal pipe, and the slurry is pushed into the conical spray rack 502 along the spiral conveyor frame and the metal pipe. A reinforcing hoop 503 is provided on the outer periphery of the middle cylinder 5.

[0056] Affected by the continuous conveying and pressurizing of the spiral conveyor frame, part of the slurry is squeezed and sprayed out along the straight nozzle 505, forming a conical slurry rain curtain in the top area of ​​the straight cylinder 506, while part of the slurry is sprayed out along the conical spray rack 502. Affected by the shape of the conical spray rack 502, the slurry forms a secondary slurry rain curtain below the conical slurry rain curtain. The conical slurry rain curtain and the secondary slurry rain curtain fall downward due to the self-weight of the slurry, forming a double-layer fixed flow trajectory in the top area of ​​the lower cone 201.

[0057] An exhaust valve 301 is provided through the center of the top of the diversion top cover 3, an inner gas collecting tank 303 connecting the upper cone 202 and the exhaust valve 301 is provided at the center of the bottom of the diversion top cover 3, and an outer gas collecting tank 302 is provided at the bottom edge of the diversion top cover 3. The slurry and the reaction material are mixed to generate part of the gas, which is collected at the top of the upper cone 202 and extracted by an external waste gas absorption tower. The lithium-containing intermediate material is leached with sulfuric acid, and sulfuric acid mist will be generated during the leaching process. The acid mist volatilized from each slurry tank and leaching tank in the process is extracted by negative pressure exhaust fan. Since the acid dissolving tank has good sealing performance, all waste gas can be effectively captured by the gas collecting device, and no unorganized waste gas is generated. The acid mist volatilized in the process is discharged through the exhaust valve 301, and after being uniformly collected by the gas collecting pipeline, it enters the "alkali spray acid mist absorption tower" for treatment and is discharged through a 15m exhaust chimney.

[0058] An outer cone sleeve 602 is provided on the periphery of the pressure plate 601, a multi-layer ring chamber 604 is provided inside the pressure plate 601, and a mixing chamber 603 penetrating the ring chamber 604 is provided at the bottom of the pressure plate 601, and a plurality of groups of positive spiral plates and reverse spiral plates are provided on the inner wall of the mixing chamber 603. During the mixing reaction of the slurry and the reaction material, the downward pressure hydraulic cylinder 6 drives the pressure plate 601 to slide down, and the pressure plate 601 slides down close to the spray cone disc 401. Affected by the main structure of the pressure plate 601, the pressure plate 601 slides down along the periphery of the spray cone disc 401 into the lower cone 201. The lower cone 201 is affected by the inner cone cylinder 203, causing its inner cavity to have a conical structure, and the pressure plate 601 is affected by the outer cone sleeve 602 to form a conical structure adapted thereto. As the pressure plate 601 continues to slide down, the inner cone cylinder 203 and the outer gap of the pressure plate 601 are gradually matched.

[0059] The mixture between the inner cone 203 and the pressure plate 601 is squeezed into the mixing chamber 603, and is guided by the inner positive spiral plate and the reverse spiral plate before mixing to form a static mixing structure, which accelerates the further mixing reaction of the mixture. The annular chamber 604 retains part of the mixture, and the mixture is continuously injected. The mixture at the top of the mixing chamber 603 is pushed to overflow on the top of the pressure plate 601, and contacts and impacts with the mixture flowing from the pressure plate 601 and the outer edge of the inner cone 203 and covering the pressure plate 601, thereby realizing single extrusion mixing.

[0060] After a single extrusion mixing is completed, the pressure plate 601 slides upward, and the mixture located at the top of the ring bin 604 and the pressure plate 601 continues to fall with the upward sliding force, and contacts and merges with the mixture retained at the bottom of the inner cone 203, forming a falling mixing.

[0061] Combining Example 1 and Example 2, it can be seen that the lithium-containing intermediate material can be processed through finely controlled steps, lithium can be efficiently extracted and impurities can be removed to ensure product purity and quality, while taking environmental protection into account, and the reaction activity of the material can be improved by roasting to increase the lithium leaching rate, and the chemical reagents can be used to adjust the pH value and purify the lithium sulfate solution. On the other hand, the slurry and the reaction material can be efficiently mixed through the hot acid reaction device and the multi-layer mixing technology to improve the lithium leaching rate and recovery efficiency; at the same time, the external hot air furnace and the waste heat recovery system are used to optimize energy utilization and reduce energy consumption. The overall process focuses on environmental protection, and the waste gas treatment device is used to ensure that the waste gas is discharged in compliance with the standards, protect the ecological environment, and promote compliant ecological recycling.

[0062] The above contents are merely examples and explanations of the structure of the present invention. The technicians in this technical field may make various modifications or additions to the specific embodiments described or replace them in a similar manner. As long as they do not deviate from the structure of the invention or exceed the scope defined by the claims, they should all fall within the protection scope of the present invention.

[0063] In the description of this specification, the description with reference to the terms "one embodiment", "example", "specific example", etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representation of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0064] The preferred embodiments of the present invention disclosed above are only used to help explain the present invention. The preferred embodiments do not describe all the details in detail, nor do they limit the invention to only specific implementation methods. Obviously, many modifications and changes can be made according to the content of this specification. This specification selects and specifically describes these embodiments in order to better explain the principles and practical applications of the present invention, so that those skilled in the art can understand and use the present invention well. The present invention is limited only by the claims and their full scope and equivalents.

Claims

1. A method for recovering battery-grade lithium carbonate from aluminum electrolysis waste residue, characterized in that: The following steps are involved: S1. Slurrying and ball-milling the lithium-containing intermediate material for wet dissolution to obtain reactant α; S2. The reactant α is transported into a hot acid reaction device, lithium is leached with sulfuric acid, lithium is leached into the solution, and a lithium-containing leachate is obtained by filtering; S3. Calcium hydroxide is added to adjust the pH value, purify and remove impurities, filter, and treat the lithium-containing solution to obtain a high-purity reactant β; S4. Add trisodium phosphate into the high-purity reactant β to precipitate lithium, centrifuge and filter, then dissolve with sulfuric acid; S5. Add calcium hydroxide, adjust the value and remove impurities; S6. Using sodium carbonate to precipitate lithium, filtering to obtain lithium carbonate, evaporating and concentrating, and crystallizing lithium carbonate to obtain a product; S7. In the electric carbon process of the lithium recovery workshop, industrial lithium carbonate is dissolved, impurity-removed, decolorized, lithium precipitated and evaporated to produce battery-grade lithium carbonate.

2. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 1, characterized in that: The hot acid reaction device comprises a limiting base (1) and a circulating furnace body (2), wherein the circulating furnace body (2) is provided with an upper cone (201) and a lower cone (202), a grading spray rack (4) inserted into the lower cone (201) is provided at the top of the limiting base (1), a spraying cone disc (401) is provided at the top of the grading spray rack (4), and a middle cylinder (5) is provided between the lower cone (201) and the upper cone (202).

3. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 2, characterized in that: A conical spray frame (502) and a straight spray port (505) are arranged inside the middle cylinder (5), a diversion cover (3) is arranged on the top of the upper cone (202), a downward pressure hydraulic cylinder (6) is arranged through the top of the diversion cover (3), and a pressure plate (601) extending to the interior of the upper cone (202) is arranged at the bottom of the downward pressure hydraulic cylinder (6).

4. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 2, characterized in that: An inner cone (203) is disposed inside the lower cone (201) and the upper cone (202), and a conical spiral cavity (206) is disposed between the inner cone (203), the lower cone (201) and the upper cone (202); an air guide valve (204) is disposed at the bottom of the lower cone (201), and an air return pipe frame (205) is disposed on the outer wall of the upper cone (202).

5. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 2, characterized in that: A telescopic cylinder column (405) is sleeved in the middle of the grading spray rack (4), and a top cone (402) is arranged on the top of the telescopic cylinder column (405). A guide groove connected to a spray cone disc (401) is arranged on the surface of the telescopic cylinder column (405). A traction pipe (403) connected to the spray cone disc (401) is arranged through the top surface of the grading spray rack (4), and an inner groove (404) is arranged at the bottom of the spray cone disc (401).

6. The thermal acid reaction device for recycling aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 3, characterized in that: A straight cylinder (506) is arranged inside the middle cylinder (5), and a threaded cavity (501) is arranged between the straight cylinder (506) and the middle cylinder (5), and the conical spray rack (502) is fixed on the inner wall of the top of the straight cylinder (506).

7. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 6, characterized in that: A straight spray port (505) is arranged on the inner wall of the top of the conical spray rack (502), a material injection pipe groove (504) penetrating the straight cylinder (506) and the middle cylinder (5) is arranged on one side of the conical spray rack (502), and a reinforcing hoop (503) is arranged on the outer periphery of the middle cylinder (5).

8. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 3, characterized in that: An exhaust valve (301) is provided through the center of the top of the diverter top cover (3), an inner gas collecting groove (303) connecting the upper cone (202) and the exhaust valve (301) is provided at the center of the bottom of the diverter top cover (3), and an outer gas collecting groove (302) is provided at the bottom edge of the diverter top cover (3).

9. The thermal acid reaction device for recovering aluminum electrolysis waste slag to prepare battery-grade lithium carbonate according to claim 3, characterized in that: An outer cone sleeve (602) is arranged on the outer periphery of the pressure plate (601), a multi-layer ring chamber (604) is arranged inside the pressure plate (601), and a mixing flow chamber (603) penetrating the ring chamber (604) is arranged at the bottom of the pressure plate (601), and a plurality of groups of positive spiral plates and reverse spiral plates are arranged on the inner wall of the mixing flow chamber (603).

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