Methods and systems for lithium extraction from solid materials

Abstract

This application provides a method and system for extracting lithium from solid materials. The method includes the following steps: mixing and reacting a liquid material with a solid material, followed by solid-liquid separation to obtain a solid product and a liquid product; wherein the liquid material contains water and sulfide ions, the solid material contains iron oxide and lithium oxide, the solid product contains iron oxide, and the liquid product contains lithium ions. The method for extracting lithium from solid materials provided by the embodiments of this application can economically and effectively extract lithium from solid materials.

Description

Technical Field

[0001] This application relates to the field of lithium extraction technology, and in particular to a method and system for extracting lithium from solid materials. Background Technology

[0002] The growth in sales of new energy vehicles has driven a continuous increase in the shipment of power batteries, leading to a surge in demand for lithium, a crucial raw material for power battery production. However, relying solely on lithium extraction from minerals would severely limit lithium production to the availability and exploitation of mineral resources, necessitating the discovery of new lithium extraction methods.

[0003] Given that some solid materials generated during current industrial production contain lithium, if lithium can be extracted from solid materials in an economical and effective manner, it will greatly alleviate the pressure on lithium resource supply. Summary of the Invention

[0004] This application provides a method and system for extracting lithium from solid materials, which can economically and effectively extract lithium from solid materials.

[0005] This application provides a method for extracting lithium from solid materials, including the following steps:

[0006] After mixing liquid and solid materials, solid and liquid products are obtained through solid-liquid separation.

[0007] The liquid material contains water and sulfur ions, the solid material contains iron oxide and lithium oxide, the solid product contains iron oxide, and the liquid product contains lithium ions.

[0008] In this embodiment, a liquid material containing water and sulfide ions is mixed and reacted with a solid material containing iron oxide and lithium oxide. The water in the liquid reacts with the lithium oxide in the solid to produce lithium ions, while the iron oxide in the solid is almost insoluble in water. The small amount of iron oxide that dissolves and produces iron ions reacts with the sulfide ions in the liquid to form ferrous sulfide precipitate. Therefore, after solid-liquid separation of the reaction mixture, lithium ions enter the liquid product, while iron oxide and ferrous sulfide enter the solid product. This allows for the economical and efficient extraction of lithium from the solid material, while simultaneously separating lithium from iron, which is beneficial for improving the purity of lithium ions in the liquid product.

[0009] In some embodiments of this application, the liquid-to-solid ratio of the liquid material to the solid material is 2L-6L:1kg;

[0010] Optionally, the mixing is carried out under stirring conditions, and the stirring rate is 120-150 r / min;

[0011] Optionally, the mixing time is 0.5-1.5 hours;

[0012] Optionally, the mixing temperature is 65-92°C;

[0013] Optionally, the sulfide ion content of the liquid material is 0.05-1 g / L;

[0014] Optionally, the sulfide ion content of the liquid product is 2.5-50 mg / L;

[0015] Optionally, the pH of the reaction solution is maintained at 5-8 during the mixing process.

[0016] In some embodiments of this application, the liquid material is obtained by pre-lithiation treatment of the first battery recycled material to obtain lithium extraction liquid, and the lithium extraction liquid is obtained by purification treatment;

[0017] Optionally, the preliminary lithium treatment includes acid leaching of the first battery recyclable to obtain lithium extraction solution, or mixing and roasting it with acid or reducing agent and then leaching it with a leaching agent to obtain lithium extraction solution;

[0018] Optionally, the leaching agent includes either acid or water;

[0019] Optionally, the acid includes sulfuric acid, or the reducing agent includes carbon and / or hydrogen.

[0020] Optionally, the calcination temperature is 250-600℃; and / or the calcination time is 0.5-3h;

[0021] Optionally, the first battery recyclable material includes at least one of lithium-ion battery recyclable material, lithium-ion battery recyclable material, and lithium-ion battery recyclable material.

[0022] In some embodiments of this application, the solid material is obtained by calcining a second battery recyclable under an oxygen-containing atmosphere;

[0023] Optionally, the calcination temperature is in the range of 1060-1380℃;

[0024] Optionally, the calcination time is 6-30 min, preferably 12-24 min;

[0025] Optionally, the calcination includes a first-stage calcination and a second-stage calcination performed sequentially, wherein the calcination temperature of the first-stage calcination is lower than the calcination temperature of the second-stage calcination;

[0026] Optionally, the excess gas coefficient of the oxygen-containing atmosphere is 1.35-1.7;

[0027] Optionally, the mass ratio of the second battery recyclable to the first battery recyclable is 0.8-4:1, preferably 2-3:1;

[0028] Optionally, the second battery recyclable includes lithium iron phosphate battery recyclable.

[0029] In some embodiments of this application, the purification process includes adding a precipitant to the lithium extraction solution to carry out a precipitation reaction, and then obtaining the liquid material by solid-liquid separation after the reaction;

[0030] Optionally, the precipitant includes a sulfide, preferably sodium sulfide;

[0031] Optionally, the precipitant includes an alkaline substance, preferably sodium hydroxide;

[0032] Optionally, the lithium content of the liquid material is 3-16 g / L;

[0033] Optionally, the sodium content of the liquid material is 2.5-10 g / L;

[0034] Optionally, the pH value of the liquid material is 5-8.

[0035] In some embodiments of this application, before performing preliminary lithium treatment on the first battery recyclable, the method further includes: pyrolyzing the first battery recyclable to obtain pyrolysis post-material, and using the pyrolysis post-material for preliminary lithium treatment.

[0036] In some embodiments of this application, the method further includes: adjusting the pH value of the liquid product to alkaline, concentrating and cooling crystallizing to obtain a cooled crystallized liquid and a cooled crystallized product, and then post-processing the cooled crystallized liquid to obtain a lithium hydroxide product.

[0037] Optionally, the cooled crystallization product is processed to obtain sodium sulfate product;

[0038] Optionally, the cooling crystallization temperature is 0-20°C;

[0039] Optionally, the mass percentage of sodium sulfate in the cooled crystallized liquid is ≤15%;

[0040] Optionally, the lithium content of the cooled crystallized liquid is ≥5 g / L;

[0041] Optionally, before concentration, an alkali is added to the liquid product to adjust the pH to 13-14.5.

[0042] Another embodiment of this application provides a system for extracting lithium from solid materials, including a calcination system, a lithium precursor system, a purification system, and a mixing system, wherein the calcination system and the mixing system are connected, and the lithium precursor system is sequentially connected to the purification system and the mixing system;

[0043] The calcination system is used to calcine the second battery recycled material to obtain solid material;

[0044] The pre-lithiation system and the purification system are used to sequentially process the first battery recycled material with pre-lithiation and purification to obtain liquid material.

[0045] The mixing system is used to mix liquid and solid materials, and then separate the liquid and solid materials to obtain a solid product containing iron oxide and a liquid product containing lithium ions.

[0046] In some embodiments of this application, the calcination system includes a primary calcination system and a secondary calcination system, wherein the primary calcination system is sequentially connected to the secondary calcination system and the mixing system;

[0047] The primary calcination system and the secondary calcination system are used to process the second battery recycled material through primary calcination and secondary calcination to obtain solid material.

[0048] In some embodiments of this application, a pyrolysis system is also included, which is connected to the prerequisite lithium system and is used to send the first battery recyclable material into the prerequisite lithium system after pyrolysis treatment.

[0049] In some embodiments of this application, a concentration system, a cooling crystallization system, and a post-processing system are also included, wherein the mixing system is sequentially connected to the concentration system, the cooling crystallization system, and the post-processing system;

[0050] The concentration system and the cooling crystallization system are used to concentrate and cool crystallize the liquid product obtained from the mixing system in sequence to obtain a cooled crystallized liquid and a cooled crystallized product.

[0051] The post-processing system is used to process the cooled crystallized liquid to obtain lithium hydroxide product.

[0052] Additional technical solutions and advantages of this application will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of this application. Attached Figure Description

[0053] To more clearly illustrate the specific embodiments of this application or the technical solutions in the prior art, the drawings used in the description of the specific embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are some embodiments of this application. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0054] Figure 1 This is a flowchart illustrating one implementation of the method and system of this application;

[0055] Figure 2This is a schematic diagram of one implementation of the purification system of this application. Detailed Implementation

[0056] The "range" disclosed in this application is defined by a lower limit and an upper limit. A given range is defined by selecting a lower limit and an upper limit, which define the boundaries of a particular range. Ranges defined in this way can include or exclude endpoints and can be arbitrarily combined; that is, any lower limit can be combined with any upper limit to form a range. For example, if ranges of 60-120 and 80-110 are listed for a specific parameter, it is expected that ranges of 60-110 and 80-120 are also included. Furthermore, if minimum range values ​​of 1 and 2 are listed, and if maximum range values ​​of 3, 4, and 5 are listed, then the following ranges are all expected: 1-3, 1-4, 1-5, 2-3, 2-4, and 2-5. In this application, unless otherwise stated, the numerical range "ab" represents a shortened representation of any combination of real numbers between a and b, where a and b are real numbers. For example, the numerical range "0-5" indicates that all real numbers between "0-5" have been listed in this article; "0-5" is simply a shortened representation of these numerical combinations. Furthermore, when a parameter is stated as an integer ≥2, it is equivalent to disclosing that the parameter is, for example, an integer such as 2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, etc.

[0057] Unless otherwise specified, all embodiments and optional embodiments of this application can be combined to form new technical solutions.

[0058] Unless otherwise specified, all technical features and optional technical features of this application may be combined to form new technical solutions.

[0059] Unless otherwise specified, all steps in this application may be performed sequentially or randomly, preferably sequentially. For example, the method includes steps (a) and (b), indicating that the method may include steps (a) and (b) performed sequentially, or it may include steps (b) and (a) performed sequentially. For example, the mention that the method may also include step (c) indicates that step (c) may be added to the method in any order. For example, the method may include steps (a), (b), and (c), or it may include steps (a), (c), and (b), or it may include steps (c), (a), and (b), etc.

[0060] Unless otherwise specified, the terms "comprising" and "including" as used in this application can be open-ended or closed-ended. For example, "comprising" and "including" can mean that other components not listed may also be included, or that only the listed components may be included.

[0061] Unless otherwise specified, the term "or" is inclusive in this application. For example, the phrase "A or B" means "A, B, or both A and B". More specifically, the condition "A or B" is satisfied by any of the following conditions: A is true (or exists) and B is false (or does not exist); A is false (or does not exist) and B is true (or exists); or both A and B are true (or exist).

[0062] In this application, the liquid-to-solid ratio refers to the ratio of the amount of liquid material to the amount of solid material used.

[0063] In this application, the first battery recyclable and the second battery recyclable can be the same or different battery recyclables.

[0064] In this application, battery recyclables refer to a mixture containing a positive electrode recovered from a battery, wherein the battery can be a nickel-sulfur secondary battery, a nickel-metal hydride secondary battery, a lithium-ion secondary battery, etc. In some examples, the lithium-ion secondary battery can include a lithium iron phosphate battery. In some examples, the positive electrode of the lithium-ion secondary battery includes a positive electrode current collector and a positive electrode active material. The positive electrode current collector can be a metal foil such as aluminum, copper, or nickel, and the positive electrode active material can include valuable metals such as nickel (Ni), cobalt (Co), manganese (Mn), and lithium (Li). In some specific examples, battery recyclables can be a mixture containing valuable metals such as Ni, Co, Mn, and Li, and carbon powder, obtained through processes such as dismantling, crushing, screening, pyrolysis, and sorting.

[0065] In some embodiments of this application, the battery recyclables include lithium iron phosphate battery recyclables and at least one of lithium-ion battery recyclables, lithium-ion battery recyclables, and lithium-ion battery recyclables.

[0066] In some embodiments of this application, the lithium iron phosphate battery recyclables are battery recyclables whose cathode material contains lithium iron phosphate. The unary lithium battery recyclables refer to battery recyclables whose cathode material includes lithium and at least one of nickel, cobalt, manganese, and aluminum. For example, the unary lithium battery recyclables may be lithium manganese oxide battery recyclables or lithium cobalt oxide battery recyclables. The binary lithium battery recyclables refer to battery recyclables whose cathode material includes lithium and at least two of nickel, cobalt, manganese, and aluminum. For example, the binary lithium battery recyclables may be lithium nickel manganese oxide battery recyclables or lithium nickel cobalt oxide battery recyclables. The ternary lithium battery recyclables refer to battery recyclables whose cathode material includes lithium and at least three of nickel, cobalt, manganese, and aluminum. For example, the ternary lithium battery recyclables may be lithium nickel cobalt manganese oxide battery recyclables or lithium nickel cobalt aluminum oxide battery recyclables.

[0067] In this application, the gas excess coefficient refers to the ratio of the actual amount of gas used to the theoretical amount used, which can be used to indicate the degree of gas excess. The theoretical amount used refers to the amount of gas required for the complete reaction of the raw materials. In some embodiments of this application, when evaluating the gas excess coefficient of an oxygen-containing atmosphere, the theoretical amount of gas used refers to the amount of gas required to completely decompose lithium iron phosphate and completely oxidize graphite in the lithium iron phosphate battery recyclables.

[0068] Please refer to Figure 1 As shown, this application provides a method for extracting lithium from solid materials. The method includes: mixing and reacting liquid materials with solid materials to obtain a reaction liquid, and separating the reaction liquid into solid and liquid products to obtain a solid product and a liquid product; wherein the liquid material contains water and sulfur ions, the solid material contains iron oxide and lithium oxide, the solid product contains iron oxide, and the liquid product contains lithium ions.

[0069] The method for extracting lithium from solid materials provided in this application involves mixing and reacting a liquid material containing water and sulfide ions with a solid material containing iron oxide and lithium oxide. The water in the liquid material reacts with the lithium oxide in the solid material to produce lithium ions. The iron oxide in the solid material is almost insoluble in water, and the small amount of iron oxide that dissolves will react with the sulfide ions in the liquid material to form ferrous sulfide precipitate. Therefore, after solid-liquid separation of the reaction liquid, lithium ions enter the liquid product, while iron oxide and a small amount of ferrous sulfide enter the solid product. This allows for the extraction of lithium from the solid material while simultaneously separating lithium from iron, which is beneficial for improving the purity of lithium ions in the liquid product. Furthermore, since the iron oxide is separated and enters the solid product, the main component of the resulting solid product is iron oxide, thus also yielding a product containing iron oxide.

[0070] It should be noted that the solid-liquid separation method can be any method well known in the art for separating solids and liquids. For example, solid-liquid separation can be carried out by centrifugation, tilting, filtration, etc., and the solid-liquid separation in this article can be carried out with reference to the above methods.

[0071] To more fully convert lithium oxide in the solid material into lithium ions, the mixing reaction conditions should be controlled within a suitable range. In some embodiments, the liquid-to-solid ratio of the liquid material to the solid material is 2L-6L:1kg; and / or the mixing reaction is carried out under stirring at a stirring rate of 120-150 r / min; and / or the mixing reaction time is 0.5-1.5 h; and / or the mixing reaction temperature is 65-92°C. By selectively controlling the amount of liquid and solid material, the stirring rate, the mixing reaction time, or the mixing reaction temperature within the above ranges, lithium oxide can react fully with water to obtain lithium ions. Simultaneously, the stirring reaction can prevent the reduction in lithium recovery rate caused by the entrainment of small amounts of lithium during the deposition of iron oxide and ferrous sulfide, thereby improving the lithium recovery rate.

[0072] Furthermore, since iron oxide dissolves more readily in strongly acidic conditions, generating iron ions, which can enter the liquid products and affect the purity of lithium ions, the pH of the reaction solution can be controlled to maximize the separation of lithium and iron. In some embodiments, the pH of the reaction solution is maintained at 5-8 during the mixing reaction to minimize the generation of iron ion impurities from the dissolution of iron oxide. Specifically, during the mixing reaction, the pH of the reaction solution can be monitored in real time, and the pH can be adjusted within the aforementioned range by adding an appropriate amount of acid, such as sulfuric acid.

[0073] It should be noted that when the pH value of the reaction solution controlling the mixed reaction is greater than 7, that is, when the reaction solution is alkaline, there are more hydroxide ions in the reaction solution, thus a liquid product containing lithium hydroxide can be obtained.

[0074] In some embodiments, the pH value of the liquid material is 5-8, that is, the pH value of the raw materials for the mixed reaction is 5-8. This is more conducive to maintaining the pH value of the reaction solution of the mixed reaction within the range of 5-8 after mixing the liquid material with the solid material.

[0075] Furthermore, when the pH of the reaction solution in the mixed reaction is 5-8 and under stirring conditions, the sulfur ions in the reaction solution will be converted into hydrogen sulfide and escape. The escape rate of sulfur in the form of hydrogen sulfide is 50-95%, where the escape rate = the content of sulfur ions that generate hydrogen sulfide / the total content of sulfur ions.

[0076] The main reactions that occur during the mixed reaction process include:

[0077] Li₂O + H₂O → 2LiOH;

[0078] In addition, small amounts of substances undergo reactions including:

[0079] Fe₂O₃ + 6H⁺ → 2Fe 3+ +3H2O;

[0080] 2Fe 3+ +3S 2- →2FeS+S;

[0081] 2Fe 3+ +4S 2- +2H + →2FeS+H2S+S.

[0082] Through the above reaction, the iron ions produced by the dissolution of iron oxide can be converted into ferrous sulfide, elemental sulfur, and hydrogen sulfide. Ferrous sulfide and elemental sulfur are precipitates and can be removed through solid-liquid separation. Hydrogen sulfide escapes from the reaction solution as a gas, thus achieving complete removal of iron ions from the mixed reaction solution. Furthermore, because iron and sulfur ions react completely, they do not accumulate, eliminating the need for periodic wastewater discharge to control impurity ions such as iron ions in the wastewater. This reduces wastewater discharge and facilitates the economical and efficient extraction of lithium from solid materials.

[0083] Since the solid product contains not only iron oxide but also small amounts of ferrous sulfide and elemental sulfur, it is necessary to separate the ferrous sulfide and elemental sulfur to obtain the iron oxide product. In some embodiments, the solid product can be subjected to sulfur sublimation treatment and ferrous sulfide oxidation treatment in sequence to obtain a pure iron oxide product.

[0084] In some embodiments, the sulfur ion content of the liquid material is 0.05-1 g / L, which is conducive to the full reaction of sulfur ions and iron ions, thereby fully removing iron ions.

[0085] After the mixing reaction, the contents of sulfur ions and iron ions in the post-reaction liquid decrease to extremely low values. Specifically, during the mixing reaction, more than 95% of the sulfur ions are converted into ferrous sulfide, elemental sulfur, and hydrogen sulfide gas, leaving only a very small amount of sulfur ions in the post-reaction liquid. In some embodiments, after solid-liquid separation of the post-reaction liquid, the sulfur ion content of the resulting liquid product is 2.5-50 mg / L, and the iron content (ferrous ferrous + ferric ferrous ...

[0086] In some embodiments, the source of the liquid material may include: obtaining a lithium extraction solution by subjecting the first battery recovery material to preliminary lithium treatment, and then purifying the lithium extraction solution to obtain the liquid material. The preliminary lithium treatment converts the lithium contained in the first battery recovery material into a soluble lithium-ion form. Specific preliminary lithium treatment methods can employ existing methods such as salting lithium extraction, chloride lithium extraction, nitration lithium extraction, reduction acid leaching lithium extraction, carbon reduction lithium extraction, and sulfation lithium extraction. After the first battery recovery material undergoes preliminary lithium treatment and purification, the liquid material may contain lithium ions. During the mixing reaction, the lithium ions in the liquid material can ultimately enter the liquid product. Therefore, the lithium contained in the first battery recovery material can be fully utilized, and the purity of lithium ions in the resulting liquid product can be improved.

[0087] In some embodiments, the first battery recyclable material includes at least one of lithium-ion battery recyclable material, lithium-ion battery recyclable material, and lithium-ion battery recyclable material. Since the lithium-ion batteries on the market are mainly ternary lithium-ion batteries and lithium iron phosphate batteries, recyclable materials from these two mainstream batteries are preferentially selected as raw materials when obtaining liquid materials. The following describes the source of liquid materials in embodiments of this application in detail, using the example of the first battery recyclable material including ternary lithium-ion battery recyclable material.

[0088] In some embodiments, the preliminary lithium treatment includes calcining a mixture of ternary lithium battery recyclables and acid, followed by leaching with a leaching agent to obtain a lithium extraction solution. For example, calcining a mixture of ternary lithium battery recyclables and sulfuric acid, followed by leaching with sulfuric acid / water, may result in the following reactions:

[0089] Li2MeO2+H2SO4→Li2SO4+MeO+H2O.

[0090] In the above reaction, Me can be metallic elements such as nickel, cobalt, and manganese, which can originate from the nickel, cobalt, and manganese contained in ternary lithium battery recyclables. Through the above reaction, the lithium contained in the ternary lithium battery recyclables can be converted into soluble lithium sulfate, while the nickel, cobalt, and manganese can be converted into oxides or sulfates, so as to remove the nickel, cobalt, and manganese during the purification process, thereby obtaining a liquid material mainly containing lithium.

[0091] In some embodiments, since the tail gas produced by lithium extraction through sulfation roasting contains sulfur, the tail gas can be wet-washed and used to prepare sulfuric acid, and the prepared sulfuric acid can be recycled back to sulfation roasting, thereby saving raw material consumption.

[0092] In some embodiments, the preliminary lithium treatment may further include the operation of mixing and roasting ternary lithium battery recyclables with a reducing agent, followed by leaching with a leaching agent to obtain a lithium extraction solution. For example, the ternary lithium battery recyclables are mixed with a reducing agent such as carbon and / or hydrogen, subjected to reduction roasting, and then leached with sulfuric acid / water to obtain a lithium extraction solution. The lithium in the ternary lithium battery recyclables is converted into lithium carbonate / lithium hydroxide by the reducing agent, followed by leaching with sulfuric acid / water. During the purification process, the pH value is adjusted to dissolve the lithium carbonate into lithium ions, thereby obtaining a liquid material mainly containing lithium.

[0093] To extract lithium more fully from ternary lithium battery recyclables, the roasting conditions should be controlled within a suitable range. In some embodiments, the roasting temperature is 250-600°C; and / or the roasting time is 0.5-3 hours. This facilitates thorough roasting and lithium extraction from the ternary lithium battery recyclables, thereby improving the lithium recovery rate.

[0094] In some embodiments, the preliminary lithium treatment may further include directly acid leaching the ternary lithium battery recyclables to obtain a lithium extraction solution, for example, by directly leaching lithium and elements such as nickel, cobalt, and manganese from the ternary lithium battery recyclables using sulfuric acid. After acid leaching, impurity elements such as nickel, cobalt, and manganese are removed through purification treatment to obtain a liquid material whose main component is lithium.

[0095] To more fully extract lithium from ternary lithium battery recyclables, in some embodiments, the recyclables are first pyrolyzed to obtain pyrolysis feedstock before undergoing preliminary lithium treatment. This feedstock is then used for preliminary lithium treatment. For example, the pyrolysis temperature can be controlled at 320-480°C, and the pyrolysis time at 1-3 hours. This removes the electrolyte from the recyclables, allowing for lithium extraction from the feedstock.

[0096] In some embodiments, when using roasting for preliminary lithium treatment, the tail gas generated from pyrolysis can be used as a heat source for roasting and lithium extraction to improve energy efficiency. Specifically, the tail gas from pyrolysis is first recycled to recover electrolyte, and then most of the organic matter is converted into CO2 and water through regenerative combustion / catalytic combustion, which is then used as a heat source for roasting and lithium extraction.

[0097] Because recycled ternary lithium batteries contain metal elements such as nickel, cobalt, and manganese, these metal elements are converted into corresponding ionic forms during the pre-lithiation process. Therefore, it is necessary to remove these metal elements to avoid introducing impurities into the liquid material. In some embodiments, the purification process includes adding a precipitant to the pre-lithiation treated material, i.e., the lithium extraction liquid, to carry out a precipitation reaction. After the reaction, the liquid material is obtained through solid-liquid separation. During the precipitation reaction, the precipitant can react with ions of nickel, cobalt, and manganese to generate corresponding metal precipitates. Solid-liquid separation can then separate lithium ions from impurities such as nickel, cobalt, and manganese.

[0098] In some embodiments, the precipitant includes sulfides, preferably sodium sulfide. By reacting sodium sulfide with ions of nickel, cobalt, manganese, etc., sulfide precipitates such as nickel sulfide, cobalt sulfide, and manganese sulfide can be generated, while lithium ions remain in the liquid phase, thereby obtaining a liquid material mainly containing lithium ions.

[0099] In other alternative embodiments, the precipitant may also include an alkaline substance, preferably sodium hydroxide. The reaction of sodium hydroxide with the ions of metals such as nickel, cobalt, and manganese can generate hydroxide precipitates such as nickel hydroxide, cobalt hydroxide, and manganese hydroxide, thus achieving effective separation of lithium from metals such as nickel, cobalt, and manganese.

[0100] In some embodiments, after preliminary lithium treatment and purification, the precipitates resulting from the conversion of metal elements such as nickel, cobalt, and manganese can be further processed to recover these metals, thereby improving the utilization rate of ternary lithium battery recyclables. Furthermore, if tail gas containing sulfur dioxide and sulfur trioxide is generated during the process of treating the precipitates to recover these metal elements, the tail gas can be used to produce sulfuric acid, thus supplementing sulfuric acid raw materials for other processes requiring sulfuric acid, such as sulfation roasting and pH adjustment in mixed reactions.

[0101] In some embodiments, after purification to remove impurities such as nickel, cobalt, and manganese, the resulting liquid material has a lithium content of 3-16 g / L, thereby achieving full recovery of lithium contained in the ternary lithium battery recyclables. At this point, due to the high lithium content of the liquid material, which is locally close to saturation, if stirring is not performed during the mixing reaction, the lithium oxide contained in the solid material will be difficult to dissolve due to the common ion effect, even if the liquid material is mixed with the solid material. However, in this embodiment, by mixing the liquid material and solid material while stirring, the liquid and solid materials can be fully mixed and contacted, thus allowing as much lithium oxide contained in the solid material as possible to dissolve, which is beneficial to improving the lithium recovery rate from the solid material.

[0102] In some embodiments, in addition to precipitating ions such as nickel, cobalt, and manganese, the purification process may also include adding a defluorinating agent to the lithium-treated material (i.e., the lithium extraction liquid) to remove fluoride, adding a heavy-duty agent to remove calcium and magnesium, performing solid-liquid separation such as pressure filtration, and removing organic matter, thereby removing most of the impurities such as nickel, cobalt, manganese, fluorine, and organic matter, to obtain a liquid material with a higher lithium content. For example, after purification, the composition of the liquid material may include: lithium content 3-16 g / L, nickel, cobalt, and manganese content ≤10 mg / L, fluoride content ≤10 mg / L, calcium ion concentration ≤20 mg / L, sodium ion content 2.5-10 g / L, and sulfur ion content 0.05-1 g / L.

[0103] The following section uses the second type of battery recycling, including lithium iron phosphate battery recycling, as an example to detail the source of solid materials in this application.

[0104] In some embodiments, the source of the solid material may include: obtaining solid material by calcining lithium iron phosphate battery recyclables in an oxygen-containing atmosphere; wherein the oxygen-containing atmosphere may include oxygen, oxygen-enriched air, or an air atmosphere, etc., and fuel such as natural gas or hydrogen-containing exhaust gas may be added during calcination to aid combustion, and the amount of fuel used may be adjusted according to the combustion temperature. Chemical reactions that may occur during the calcination process include:

[0105] 2LiFePO4+1 / 2O2→Li2O+Fe2O3+P2O5;

[0106] 3C + O2 → 2CO + CO2.

[0107] After the calcination reaction, the generated P2O5, CO, CO2, N2, and excess O2 enter the calcination tail gas, while the remaining solid material includes lithium oxide and iron oxide. Thus, lithium and iron can be separated by mixing and reacting the solid material with the liquid material obtained in the above embodiment, and a liquid product containing lithium ions and a solid product containing iron oxide can be prepared.

[0108] To improve calcination efficiency and ensure that lithium iron phosphate battery recyclables are fully converted into solid materials containing lithium oxide and iron oxide, calcination conditions can be controlled within a suitable range. In some embodiments, the calcination temperature is 1060-1380°C; and / or the calcination time is 6-30 min, preferably 12-24 min. For example, the calcination temperature can be any value between 1060℃, 1080℃, 1100℃, 1120℃, 1140℃, 1160℃, 1180℃, 1200℃, 1220℃, 1240℃, 1250℃, 1260℃, 1280℃, 1300℃, 1320℃, 1340℃, 1360℃, 1380℃, or 1060-1380℃; the calcination time can be any value between 6min, 8min, 10min, 12min, 14min, 16min, 18min, 20min, 22min, 24min, 26min, 28min, 30min, or 6-30min.

[0109] In some embodiments, calcination includes subjecting the lithium iron phosphate battery recyclables to a first-stage calcination lasting for a period of time and a second-stage calcination lasting for a period of time in an oxygen-containing atmosphere, wherein the calcination temperature of the first-stage calcination is lower than that of the second-stage calcination. By performing two-stage calcination in stages, lithium iron phosphate can be decomposed as much as possible, which is beneficial for subsequent recovery of high-purity lithium oxide, iron oxide, and phosphoric acid. At the same time, it helps to reduce the concentration of nitrogen oxides in the calcination tail gas, thereby reducing denitrification costs, and also helps to improve the quality of phosphoric acid (by reducing the nitric acid concentration in the phosphoric acid).

[0110] In some embodiments, the calcination temperature of the first-stage calcination is in the range of 1060-1250°C, preferably in the range of 1100-1250°C; and / or the calcination time is 4-20 min, preferably 8-16 min. The reactions occurring during the first-stage calcination process include:

[0111] 4LiFePO4+3O2+2C→2Li2CO3+2Fe2O3+2P2O5;

[0112] Li2CO3→Li2O+CO2;

[0113] C + O2 → CO2.

[0114] After primary calcination, most of the lithium iron phosphate battery recyclables are converted into CO / CO2, Fe2O3, and P2O5. Furthermore, graphite affects the decomposition of lithium iron phosphate, specifically by encapsulating lithium iron phosphate and adsorbing oxygen, thus reducing the decomposition efficiency. By performing primary calcination before the higher-temperature secondary calcination step, some of the graphite can be oxidized. For example, in some embodiments, the conversion rate of graphite to carbon dioxide during primary calcination is 30-70%, thereby reducing the extent to which lithium iron phosphate is encapsulated by graphite, which is beneficial for lithium iron phosphate decomposition and improves the recovery rate of all components, including lithium, iron, and phosphorus, in the lithium iron phosphate battery recyclables. After primary calcination, most of the lithium iron phosphate has decomposed; subsequent secondary calcination ensures that the remaining lithium iron phosphate is nearly completely decomposed.

[0115] It should also be noted that excessively low primary calcination temperatures are detrimental to the effective decomposition of lithium iron phosphate, leading to a decrease in lithium recovery rate; excessively high temperatures result in high calcination fuel consumption and high nitrogen oxide concentrations, thereby reducing the quality of the subsequently recovered phosphoric acid and increasing tail gas treatment costs. However, within the suitable temperature range of this application embodiment, lithium iron phosphate can be fully decomposed, thereby improving the recovery rate of all components, including lithium, iron, and phosphorus, in the lithium iron phosphate battery recyclables, while also reducing calcination fuel consumption, lowering the nitrogen oxide concentration in the tail gas, and saving production costs.

[0116] In some embodiments, the calcination temperature of the secondary calcination is in the range of 1250-1380°C, preferably in the range of 1280-1350°C; and / or the calcination time is 2-10 min, preferably 4-8 min. At the above-mentioned suitable calcination temperature and / or calcination time, by performing secondary calcination at a higher temperature, the lithium iron phosphate battery recyclables (including lithium iron phosphate and graphite) remaining from the primary calcination process can be essentially completely decomposed and converted into CO, CO2, Fe2O3, and P2O5, thereby improving the recovery rates of lithium, iron, and phosphorus.

[0117] Because of the two-stage calcination process, the calcination conditions of the first and second stages can be rationally adjusted according to the ease of decomposition of lithium iron phosphate battery recyclables under actual calcination conditions. This reduces pollution, improves the recovery rates of phosphorus, iron, and lithium, increases the purity of the product phosphoric acid, and reduces peroxidation problems during the calcination process. Furthermore, since the first-stage calcination is longer and at a relatively lower temperature, compared to high-temperature calcination throughout the entire process, the two-stage calcination reduces the reaction between nitrogen and oxygen at high temperatures, reducing the generation of nitrogen oxides and thus lowering the concentration of nitrogen oxides in the exhaust gas. This facilitates the absorption of the exhaust gas in subsequent steps to obtain higher-purity phosphoric acid (with reduced nitric acid concentration).

[0118] In some embodiments, the heating rate for the primary and secondary calcinations is 1-3 °C / min, where the heating rate refers to the rate of increase during the period from the temperature of the primary calcination to the temperature required for the secondary calcination. Since the calcination process takes place at relatively high temperatures, if the heating rate is too low, the heating time is too long, or the heating rate is too high, thermal strain can easily occur in the calcination equipment, making it brittle and even causing breakage. In this embodiment, by controlling the heating rate of the calcination temperature at 1-3 °C / min, sufficient calcination can be achieved, damage to the calcination equipment can be reduced, and the service life of the equipment can be improved.

[0119] Furthermore, controlling the excess gas coefficient of the oxygen-containing atmosphere within a suitable range also promotes the calcination effect. In some embodiments, the excess gas coefficient of the oxygen-containing atmosphere is 1.35-1.7. For example, the excess gas coefficient of the oxygen-containing atmosphere can be any value between 1.35, 1.4, 1.45, 1.5, 1.55, 1.6, 1.65, 1.7, or 1.35-1.7.

[0120] In some embodiments, the oxygen consumption of the primary calcination stage accounts for 80-95% of the total oxygen consumption of the primary and secondary calcinations. By rationally allocating the oxygen consumption of the primary and secondary calcinations, it is beneficial to fully decompose the lithium iron phosphate battery recyclables through staged calcination, thereby improving the recovery rate of phosphorus, iron, and lithium.

[0121] Since the exhaust gas from calcination contains P2O5, this P2O5 can be used to prepare phosphoric acid, thereby recovering phosphorus and improving the utilization rate of lithium iron phosphate battery recyclables. In some embodiments, the gaseous material obtained from calcining lithium iron phosphate battery recyclables can be acid-washed to obtain phosphoric acid product, thus achieving the recovery of phosphorus from the lithium iron phosphate battery recyclables. For example, phosphoric acid with a mass fraction of 75-95% can be used for washing, which can fully recover phosphorus and obtain phosphoric acid product. The reactions that occur during the acid washing process include:

[0122] 3H₂O + P₂O₅ → 2H₃PO₄.

[0123] In some embodiments, the pickling temperature is 45-162°C; and / or the pickling pressure is 0.05-0.6 MPa, which is beneficial for the full recovery of phosphorus pentoxide. It should be noted that the pickling temperature refers to the temperature of the acid used, and the pickling pressure refers to the pressure of the acid used; for example, when using a spray pickling method, it refers to the spray pressure.

[0124] In some embodiments, the calcined product from the first calcination can be directly acid-washed without undergoing a second calcination. In this case, the P2O5 contained in the calcined product from the first calcination can also be used to prepare phosphoric acid products.

[0125] In some embodiments, the tail gas generated during the pickling process can be mixed with the tail gas from the sulfation roasting lithium extraction process as a heat source for sulfation roasting lithium extraction. Specifically, the organic combustibles and a small amount of hydrogen contained in the tail gas are used as the roasting heat source. This helps to reduce the SO2 / acid mist concentration in the tail gas from sulfation roasting lithium extraction and saves energy. The waste residue generated during the pickling process can be recycled as roasting feedstock for sulfation roasting, thereby further and more fully extracting lithium.

[0126] In some embodiments, the solid material can be abraded before being mixed with the liquid material. For example, the solid material can be cooled and ball-milled to a smaller particle size before being mixed with the liquid material, which is beneficial for the solid and liquid materials to react fully.

[0127] To maximize the extraction of lithium from ternary lithium battery recyclables and lithium iron phosphate battery recyclables, the ratio of these raw materials can be controlled within a suitable range. In some embodiments, the mass ratio of lithium iron phosphate battery recyclables to ternary lithium battery recyclables is 0.8-4:1, preferably 2-3:1. Within this relative range, the lithium and iron contained in the ternary lithium battery recyclables and lithium iron phosphate battery recyclables can be fully extracted while reducing the consumption of auxiliary materials in the lithium extraction process.

[0128] In the process of obtaining liquid feedstock from ternary lithium battery recyclables, when sodium sulfide or sodium hydroxide is used as a precipitant for purification, an excess of sodium sulfide or sodium hydroxide is generally added to ensure sufficient precipitation of metals such as nickel, cobalt, and manganese. Therefore, the liquid feedstock may still contain some sodium ions. In some embodiments, the sodium content of the liquid feedstock is 2.5-10 g / L. The sodium contained in the liquid feedstock will eventually enter the liquid product, so it is necessary to remove sodium ions from the liquid product in order to obtain a liquid product with high lithium ion purity.

[0129] In some embodiments, the method for extracting lithium from solid materials further includes: adjusting the pH of the liquid product to alkaline, concentrating and cooling crystallizing to obtain a cooled crystallized liquid and a cooled crystallized product, and then further processing the cooled crystallized liquid to obtain a lithium hydroxide product. For example, an alkali, such as sodium hydroxide, can be added to the liquid product to adjust the pH to alkaline. At this point, the liquid product contains a relatively high amount of hydroxide ions. Then, the liquid product is concentrated, for example by evaporation, until the salt content (which may contain sodium sulfate, lithium sulfate, etc.) in the solution is 10-22% (wt%) and the lithium content is 0.5-10 g / L. Then, by controlling the cooling crystallization temperature, for example, in the range of 0-20°C, sodium ions, sulfur ions, and sulfate ions in the liquid product crystallize out to obtain a cooled crystallized product. The cooled crystallized product can be further processed to obtain a sodium sulfate product. The lithium ions and hydroxide ions contained in the liquid product will enter the cooled crystallized liquid. For example, in some embodiments, the lithium content of the cooled crystallized liquid is ≥5 g / L. The lithium hydroxide product can be obtained by further processing the cooled crystallized liquid. Therefore, sodium sulfate, a byproduct, can be prepared simultaneously with lithium hydroxide.

[0130] In some embodiments, the sodium sulfate mass percentage of the cooled crystallized liquid is ≤15%. To further remove impurities such as sodium ions and sulfate ions, the cooled crystallized liquid can be subjected to post-processing steps such as evaporation crystallization, centrifugation, drying and packaging to obtain a lithium hydroxide product with higher purity.

[0131] In some embodiments, before concentration, an alkali, such as sodium hydroxide, is added to the liquid product to adjust the pH to 13-14.5. If anions such as sulfate are introduced during the mixing reaction of the solid and liquid materials or in a step prior to the mixing reaction, the liquid product will contain sulfate, and the lithium ions in the liquid product may exist in the form of lithium sulfate. In this embodiment, adjusting the pH of the liquid product to a strongly alkaline state is beneficial to increasing the hydroxide ion concentration in the liquid product, thereby increasing the yield of lithium hydroxide.

[0132] Please refer to Figure 1As shown, this application also provides a system for extracting lithium from solid materials, including a calcination system, a lithium preparation system, a purification system, and a mixing system. The calcination system and the mixing system are connected, and the lithium preparation system is sequentially connected to the purification system and the mixing system. The calcination system is used to perform the calcination step described in the above embodiments, thereby obtaining a solid material from the second battery recycled material after calcination. The lithium preparation system and the purification system are respectively used to perform the lithium preparation step and the purification step described in the above embodiments, thereby obtaining a liquid material from the first battery recycled material after sequential lithium preparation treatment and purification treatment. The mixing system is used to perform the mixing reaction step described in the above embodiments, thereby obtaining a reaction liquid after mixing and reacting the solid material and the liquid material, and then separating the reaction liquid to obtain a solid product containing iron oxide and ferrous sulfide and a liquid product containing lithium ions.

[0133] In this embodiment, calcining the battery recyclables using a calcination system allows for the decomposition of the second battery recyclables, facilitating the separation and recovery of elements such as lithium and iron contained within them. This yields a solid material containing iron oxide and lithium oxide, while simultaneously reducing the concentration of nitrogen oxides in the calcination exhaust gas, thereby reducing pollution and denitrification costs. Processing the first battery recyclables using a pre-lithiation system and a purification system yields a liquid material containing water and sulfur ions, allowing for the full utilization of the lithium contained within. A mixing system allows the liquid and solid materials to react, where the water in the liquid reacts with the lithium oxide in the solid to produce lithium ions. These lithium ions enter the liquid product, while the iron oxide in the solid is almost insoluble in water. Further solid-liquid separation then achieves the separation of lithium and iron. Furthermore, the small amount of iron ions entering the solution will react fully with sulfur ions to form ferrous sulfide precipitate, elemental sulfur precipitate, and hydrogen sulfide gas. Therefore, there is no accumulation of iron and sulfur ions, eliminating the need for periodic wastewater discharge to control the content of impurity ions such as iron and sulfur ions in the wastewater, thereby reducing wastewater discharge. This allows for the economical and effective extraction of lithium from solid materials, while also improving the purity of lithium ions in the liquid product.

[0134] In some embodiments, the calcination system includes a primary calcination system and a secondary calcination system, which are sequentially connected to the secondary calcination system and the mixing system. The primary calcination system and the secondary calcination system are respectively used to perform the primary calcination step and the secondary calcination step described in the above embodiments, so that the second battery recycled material is obtained as a solid material after being sequentially calcined in the primary and secondary calcinations.

[0135] In some embodiments, the system for extracting lithium from solid materials further includes a pyrolysis system connected to a lithium precursor system. The pyrolysis system is used to perform the pyrolysis steps described in the above embodiments, thereby sending the first battery recycled material into the lithium precursor system after pyrolysis treatment.

[0136] Please refer to Figure 2 As shown, in some embodiments, the purification system includes a nickel-cobalt precipitator, a fluorine removal device, a weighting device, etc. connected in sequence. The purification system is used to perform the precipitation reaction to remove nickel, cobalt, and manganese ions, the addition of a fluorine removal agent to remove fluorine, and the addition of a weighting agent to remove calcium and magnesium, as described in the above embodiments, so as to obtain a liquid material with a higher lithium content.

[0137] In some embodiments, the system for extracting lithium from solid materials further includes a concentration system, a cooling crystallization system, and a post-processing system, with the mixing system connected sequentially to the concentration system, cooling crystallization system, and post-processing system. The concentration system and cooling crystallization system are respectively used to perform the concentration step and cooling crystallization step described in the above embodiments, thereby sequentially concentrating and cooling crystallizing the liquid product obtained from the mixing system to obtain a cooled crystallized liquid and a cooled crystallized product. The post-processing system is used to perform the evaporation crystallization, centrifugal separation, drying, and packaging steps described in the above embodiments, thereby obtaining a lithium hydroxide product from the cooled crystallized liquid through post-processing.

[0138] The following embodiments describe the disclosure of this application in more detail. These embodiments are merely illustrative, as various modifications and variations will be apparent to those skilled in the art within the scope of the disclosure of this application. Unless otherwise stated, all parts, percentages, and ratios reported in the following embodiments are based on mass, and all reagents and raw materials used in the embodiments are commercially available or synthesized by conventional methods, as are the instruments used in the embodiments.

[0139] Example 1

[0140] This embodiment provides a method for extracting lithium from solid materials, including the following steps:

[0141] 1) Add ternary lithium battery recycled material (lithium content 4%, total nickel, cobalt and manganese content 40%) to the pyrolysis equipment at a flow rate of 0.4 kg / h to remove the electrolyte by pyrolysis. The pyrolysis temperature is 320℃ and the pyrolysis time is 3h. The pyrolysis tail gas is sent to step 2) as a heat source for sulfation roasting.

[0142] 2) Add the pyrolyzed ternary lithium battery recycled material to the roasting equipment and add concentrated sulfuric acid for roasting. The roasting temperature is 250℃ and the roasting time is 3h.

[0143] 3) The tail gas from sulfation roasting is wet-washed and then sent to acid production to obtain sulfuric acid. The sulfuric acid is used as the raw material for sulfation roasting. The waste residue obtained from wet washing is recycled to the roasting equipment for repeated sulfation roasting.

[0144] 4) After ball milling the sulfation roasted product, leach it with water, filter it, add sodium sulfide to the filtrate to carry out a precipitation reaction, filter it again to obtain a lithium sulfate solution. The obtained lithium sulfate solution is used as the liquid material for the mixed reaction in step 8). The lithium content in the liquid material is 9.5 g / L, the lithium sulfate mass content is 10.8%, the sulfide ion content is 0.06 g / L, the sodium content is 5 g / L, the sodium sulfate mass content is 3.9%, and the pH value of the liquid material is 6.

[0145] 5) Control the mass ratio of lithium iron phosphate battery recycled material to ternary lithium battery recycled material from step 1) to 2.5:1, that is, add lithium iron phosphate battery recycled material (lithium content 3%, phosphorus content 15%, iron content 25%) to the calcination equipment at a flow rate of 1 kg / h, and add oxygen to carry out primary calcination and secondary calcination in sequence; wherein, the temperature of primary calcination is 1100℃ and the time is 10 min; the temperature of secondary calcination is 1300℃ and the time is 6 min; the total oxygen consumption of primary calcination and secondary calcination meets the requirement of an oxygen excess coefficient of 1.7, and the oxygen consumption of primary calcination accounts for 80% of the total oxygen consumption, with the remaining oxygen supplied to secondary calcination.

[0146] After two-stage calcination, gaseous and solid feedstocks are obtained. The solid feedstock includes lithium oxide and iron oxide, while the gaseous feedstock includes phosphorus pentoxide, CO, and CO2. The gaseous feedstock, excess O2, and nitrogen oxides generated during calcination are fed into the calcination tail gas, with an emission concentration of 210 mg / Nm³. 3 The mass rate is 1.15 g / h.

[0147] 6) After recovering the waste heat from the calcination tail gas, the P2O5 in it is washed and absorbed by circulating a 95% concentrated phosphoric acid solution to obtain phosphoric acid product. The temperature of the concentrated phosphoric acid solution used for washing is 162℃ and the pressure is 0.6MPa. The yield of phosphoric acid product is 0.444kg / h, the purity is 99.7%, and the phosphorus recovery rate is 90%.

[0148] 7) The scrubbing exhaust gas is sent into the roasting equipment as a heat source for sulfation roasting and reduces the SO2 / acid mist concentration of the sulfation roasting exhaust gas.

[0149] 8) The solid material obtained after secondary calcination is cooled and ball-milled, and then mixed with the liquid material obtained in step 4). The liquid-to-solid ratio of the liquid material to the solid material is 4 L / kg. The stirring rate during the mixing reaction is 120 r / min, the time is 1 h, the temperature is 72℃, and the pH value is maintained at 6. After the mixing reaction is completed, the solid product and the liquid product are obtained by pressure filtration. The lithium sulfate content in the liquid product is 7.6%, the lithium hydroxide content is 8.9%, the sulfide ion content is 6 mg / L, and the iron (ferrous iron + ferric iron) content is less than 1 ppm. The leaching rate of iron in the solid material is 0.05%, and the leaching rate of lithium is 93.2%.

[0150] 9) The solid product mainly contains iron oxide and can be used directly as an iron oxide product. The yield of iron oxide product is 0.161 kg / h and the iron recovery rate is 92%.

[0151] 10) The pH of the liquid product is adjusted to 14 using solid or liquid alkali. After further concentration, the total content of sodium sulfate and lithium sulfate in the solution is 16% (wt%) and the lithium content is 5.5 g / L. Then, at a temperature of 0℃, liquid ammonia is used as the cooling medium to perform cooling crystallization to obtain a cooled crystallized liquid and a cooled crystallized product. The sodium sulfate concentration in the cooled crystallized liquid is 12% and the lithium content is 5.3 g / L. The cooled crystallized product is then subjected to sodium sulfate post-treatment to obtain the sodium sulfate product.

[0152] 11) After cooling and crystallizing, the liquid is evaporated, crystallized, centrifuged, dried and packaged to obtain lithium hydroxide monohydrate. The product yield of lithium hydroxide monohydrate is 0.253 kg / h, and the comprehensive lithium recovery rate is 91%, which meets the judgment standard of GB / T 26008-2020 for battery-grade lithium hydroxide monohydrate.

[0153] Example 2

[0154] This embodiment provides a method for extracting lithium from solid materials, which differs from Embodiment 1 in that the parameters and conditions of each step are different, and no pyrolysis step is involved. Specifically, it includes the following steps:

[0155] 1) Add ternary lithium battery recycled material (lithium content 4%, total nickel, cobalt and manganese content 40%) to the roasting equipment at a flow rate of 0.4 kg / h, and add concentrated sulfuric acid for roasting. The roasting temperature is 425℃ and the roasting time is 1.7h.

[0156] 2) The tail gas from sulfation roasting is wet-washed and then sent to acid production to obtain sulfuric acid. The sulfuric acid is used as the raw material for sulfation roasting. The waste residue obtained from wet washing is recycled to the roasting equipment for repeated sulfation roasting.

[0157] 3) After ball milling the sulfation roasted product, leach it with water, filter it, add sodium sulfide to the filtrate to carry out a precipitation reaction, filter it again to obtain a lithium sulfate solution. The obtained lithium sulfate solution is used as the liquid material for the mixed reaction in step 7). The lithium content in the liquid material is 7 g / L, the sulfur ion content is 0.05 g / L, and the pH value of the liquid material is 6.

[0158] 4) Control the mass ratio of lithium iron phosphate battery recycled material to ternary lithium battery recycled material from step 1) to 2.5:1, that is, add lithium iron phosphate battery recycled material (lithium content 3%, phosphorus content 15%, iron content 25%) to the calcination equipment at a flow rate of 1 kg / h, and add oxygen-enriched air to carry out primary calcination and secondary calcination in sequence; wherein, the temperature of primary calcination is 1100℃ and the time is 8 min; the temperature of secondary calcination is 1280℃ and the time is 5 min; the total oxygen-enriched air consumption of primary and secondary calcination meets the requirement that the excess oxygen-enriched air coefficient is 1.53, and the oxygen-enriched air consumption of primary calcination accounts for 87.5% of the total oxygen-enriched air consumption, with the remaining oxygen supplied to secondary calcination.

[0159] After two-stage calcination, gaseous and solid feedstocks are obtained. The solid feedstock includes lithium oxide and iron oxide, while the gaseous feedstock includes phosphorus pentoxide, CO, and CO2. The gaseous feedstock, excess O2, and nitrogen oxides generated during calcination are fed into the calcination tail gas, with an emission concentration of 209 mg / Nm³. 3 The mass rate is 1.14 g / h.

[0160] 5) After recovering the waste heat from the calcination tail gas, the P2O5 in it is washed and absorbed by circulating a 95% concentrated phosphoric acid solution to obtain phosphoric acid product. The temperature of the concentrated phosphoric acid solution used for washing is 103℃ and the pressure is 0.325MPa. The yield of phosphoric acid product is 0.499kg / h, the purity is 99.7%, and the phosphorus recovery rate is 89.5%.

[0161] 6) The scrubbing exhaust gas is sent into the roasting equipment as a heat source for sulfation roasting and reduces the SO2 / acid mist concentration of the sulfation roasting exhaust gas.

[0162] 7) After cooling and ball milling, the solid material obtained after secondary calcination is mixed with the liquid material obtained in step 3) for reaction. The liquid-to-solid ratio of the liquid material to the solid material is 4 L / kg. The stirring rate during the mixing reaction is 120 r / min, the time is 0.7 h, the temperature is 70 ℃, and the pH value is maintained at 6. After the mixing reaction is completed, the solid product and the liquid product are obtained by pressure filtration. The sulfur ion content in the liquid product is 7 mg / L, and the iron (ferrous iron + ferric iron) content is less than 1 ppm. The leaching rate of iron in the solid material is 0.07%, and the leaching rate of lithium is 90.4%.

[0163] 8) The solid product mainly contains iron oxide and can be used directly as an iron oxide product. The yield of iron oxide product is 0.16 kg / h and the iron recovery rate is 91.5%.

[0164] 9) The pH of the liquid product is adjusted to 14 using solid or liquid alkali. After further concentration, the total content of sodium sulfate and lithium sulfate in the solution is 10% (wt%) and the lithium content is 4 g / L. Then, at a temperature of 10°C, the solution is cooled and crystallized using chilled water as the cooling medium to obtain the cooled crystallized liquid and the cooled crystallized product. The sodium sulfate concentration in the cooled crystallized liquid is 12% and the lithium content is 5.1 g / L. The cooled crystallized product is then subjected to sodium sulfate post-treatment to obtain the sodium sulfate product.

[0165] 10) After cooling and crystallizing, the liquid is evaporated, crystallized, centrifuged, dried and packaged to obtain lithium hydroxide monohydrate. The product yield of lithium hydroxide monohydrate is 0.219 kg / h, and the comprehensive lithium recovery rate is 90.5%, which meets the judgment standard of GB / T 26008-2020 for battery-grade lithium hydroxide monohydrate.

[0166] Example 3

[0167] This embodiment provides a method for extracting lithium from solid materials, which differs from Embodiment 1 in that the parameters and conditions of each step are different, and no pyrolysis step is involved. Specifically, it includes the following steps:

[0168] 1) Add ternary lithium battery recycled material (lithium content 4%, total nickel, cobalt and manganese content 40%) to the roasting equipment at a flow rate of 0.4 kg / h, and add concentrated sulfuric acid for roasting. The roasting temperature is 600℃ and the roasting time is 0.5h.

[0169] 2) The tail gas from sulfation roasting is wet-washed and then sent to acid production to obtain sulfuric acid. The sulfuric acid is used as the raw material for sulfation roasting. The waste residue obtained from wet washing is recycled to the roasting equipment for repeated sulfation roasting.

[0170] 3) After ball milling the sulfation roasted product, leach it with water, filter it, add sodium sulfide to the filtrate to carry out a precipitation reaction, filter it again to obtain a lithium sulfate solution. The obtained lithium sulfate solution is used as the liquid material for the mixed reaction in step 7). The lithium content in the liquid material is 16 g / L, the sulfide ion mass content is 10%, the sulfide ion content is 0.08 g / L, and the pH value of the liquid material is 6.

[0171] 4) Control the mass ratio of lithium iron phosphate battery recycled material to ternary lithium battery recycled material from step 1) to 2.5:1, that is, add lithium iron phosphate battery recycled material (lithium content 3%, phosphorus content 15%, iron content 25%) to the calcination equipment at a flow rate of 1 kg / h, and add air to perform primary calcination and secondary calcination in sequence; wherein, the temperature of primary calcination is 1100℃ and the time is 8 min; the temperature of secondary calcination is 1300℃ and the time is 10 min; the total air consumption of primary calcination and secondary calcination meets the requirement of an air excess coefficient of 1.35, and the air consumption of primary calcination accounts for 95% of the total air consumption, with the remaining oxygen supplied to secondary calcination.

[0172] After secondary calcination, gaseous and solid feedstocks are obtained. The solid feedstock includes lithium oxide and iron oxide, while the gaseous feedstock includes phosphorus pentoxide, CO, and CO2. The gaseous feedstock, excess O2, and nitrogen oxides generated during calcination are fed into the calcination tail gas, with an emission concentration of 224 mg / Nm³. 3 The mass rate is 1.21 g / h.

[0173] 5) After recovering the waste heat from the calcination tail gas, the P2O5 in it is washed and absorbed by circulating a 95% concentrated phosphoric acid solution to obtain phosphoric acid product. The temperature of the concentrated phosphoric acid solution used for washing is 45℃ and the pressure is 0.6MPa. The yield of phosphoric acid product is 0.469kg / h, the purity is 99.5%, and the phosphorus recovery rate is 90%.

[0174] 6) The scrubbing exhaust gas is sent into the roasting equipment as a heat source for sulfation roasting and reduces the SO2 / acid mist concentration of the sulfation roasting exhaust gas.

[0175] 7) After cooling and ball milling, the solid material obtained after secondary calcination is mixed with the liquid material obtained in step 3) for reaction. The liquid-to-solid ratio of the liquid material to the solid material is 6 L / kg. The stirring rate during the mixing reaction is 150 r / min, the time is 0.5 h, the temperature is 65 ℃, and the pH value is maintained at 6. After the mixing reaction is completed, the solid product and the liquid product are obtained by pressure filtration. The sulfur ion content in the liquid product is 4 mg / L, and the iron (ferrous iron + ferric iron) content is less than 1 ppm. The leaching rate of iron in the solid material is 0.06%, and the leaching rate of lithium is 93.4%.

[0176] 8) The solid product mainly contains iron oxide and can be directly used as an iron oxide product. The yield of iron oxide product is 0.159 kg / h and the iron recovery rate is 91%.

[0177] 9) The pH of the liquid product is adjusted to 14 using solid or liquid alkali. After further concentration, the total content of sodium sulfate and lithium sulfate in the solution is 22% (wt%) and the lithium content is 10 g / L. Then, at a temperature of 20°C, propylene is used as the cooling medium to perform cooling crystallization to obtain a cooled crystallized liquid and a cooled crystallized product. The sodium sulfate concentration in the cooled crystallized liquid is 10% and the lithium content is 5.8 g / L. The cooled crystallized product is then subjected to sodium sulfate post-treatment to obtain the sodium sulfate product.

[0178] 10) After cooling and crystallizing, the liquid is evaporated, crystallized, centrifuged, dried and packaged to obtain lithium hydroxide monohydrate. The product yield of lithium hydroxide monohydrate is 0.254 kg / h, and the comprehensive lithium recovery rate is 92%, which meets the judgment standard of GB / T 26008-2020 for battery-grade lithium hydroxide monohydrate.

[0179] Example 4

[0180] This embodiment provides a method for extracting lithium from solid materials, which differs from Embodiment 1 in that: the composition of the battery recycled material is different, the parameter conditions of each step are different, and no pyrolysis step is performed. Specifically, it includes the following steps:

[0181] 1) Add ternary lithium battery recycled material (lithium content 3%, total nickel, cobalt and manganese content 31%) to the roasting equipment at a flow rate of 0.4 kg / h, and add concentrated sulfuric acid for roasting. The roasting temperature is 310℃ and the roasting time is 2.1h.

[0182] 2) The tail gas from sulfation roasting is wet-washed and then sent to acid production to obtain sulfuric acid. The sulfuric acid is used as the raw material for sulfation roasting. The waste residue obtained from wet washing is recycled to the roasting equipment for repeated sulfation roasting.

[0183] 3) After ball milling the sulfation roasted product, leach it with water, filter it, add sodium sulfide to the filtrate to carry out a precipitation reaction, filter it again to obtain a lithium sulfate solution. The obtained lithium sulfate solution is used as the liquid material for the mixed reaction in step 7). The lithium content in the liquid material is 7.6 g / L, the sulfide ion mass content is 0.08 g / L, and the pH value of the liquid material is 7.

[0184] 4) Control the mass ratio of lithium iron phosphate battery recycled material to ternary lithium battery recycled material from step 1) to 2.5:1, that is, add lithium iron phosphate battery recycled material (lithium content 3%, phosphorus content 15%, iron content 25%) to the calcination equipment at a flow rate of 1 kg / h, and add oxygen to carry out primary calcination and secondary calcination in sequence; wherein, the temperature of primary calcination is 1250℃ and the time is 8 min; the temperature of secondary calcination is 1350℃ and the time is 8 min; the total oxygen consumption of primary calcination and secondary calcination meets the requirement of an oxygen excess coefficient of 1.5, and the oxygen consumption of primary calcination accounts for 83% of the total oxygen consumption, with the remaining oxygen supplied to secondary calcination.

[0185] After secondary calcination, gaseous and solid feedstocks are obtained. The solid feedstock includes lithium oxide and iron oxide, while the gaseous feedstock includes phosphorus pentoxide, CO, and CO2. The gaseous feedstock, excess O2, and nitrogen oxides generated during calcination are fed into the calcination tail gas, with an emission concentration of 218 mg / Nm³. 3 The mass rate is 1.18 g / h.

[0186] 5) After recovering the waste heat from the calcination tail gas, the P2O5 in it is washed and absorbed by circulating a 95% concentrated phosphoric acid solution to obtain phosphoric acid product. The temperature of the concentrated phosphoric acid solution used for washing is 58℃ and the pressure of the concentrated phosphoric acid solution used for washing is 0.27MPa. The yield of phosphoric acid product is 0.495kg / h, the purity is 99.7%, and the phosphorus recovery rate is 88%.

[0187] 6) The scrubbing exhaust gas is sent into the roasting equipment as a heat source for sulfation roasting and reduces the SO2 / acid mist concentration of the sulfation roasting exhaust gas.

[0188] 7) After cooling and ball milling, the solid material obtained after secondary calcination is mixed with the liquid material obtained in step 3) for reaction. The liquid-to-solid ratio of the liquid material to the solid material is 2 L / kg. The stirring rate during the mixing reaction is 120 r / min, the time is 1 h, the temperature is 92℃, and the pH value is maintained at 7. After the mixing reaction is completed, the solid product and the liquid product are obtained by pressure filtration. The sulfur ion content in the liquid product is 10 mg / L, and the iron (ferrous iron + ferric iron) content is less than 1 ppm. The leaching rate of iron in the solid material is 0.04%, and the leaching rate of lithium is 90.2%.

[0189] 8) The solid product mainly contains iron oxide and can be used directly as an iron oxide product. The yield of iron oxide product is 0.164 kg / h and the iron recovery rate is 90%.

[0190] 9) The pH of the liquid product is adjusted to 14 using solid or liquid alkali. After further concentration, the total content of sodium sulfate and lithium sulfate in the solution is 17% (wt%) and the lithium content is 8.2 g / L. Then, at a temperature of 6°C, R410a is used as the cooling medium to perform cooling crystallization to obtain the cooled crystallized liquid and the cooled crystallized product. The sodium sulfate concentration in the cooled crystallized liquid is 15% and the lithium content is 3 g / L. The cooled crystallized product is then subjected to sodium sulfate post-treatment to obtain the sodium sulfate product.

[0191] 10) After cooling and crystallizing, the liquid is evaporated, crystallized, centrifuged, dried and packaged to obtain lithium hydroxide monohydrate. The product yield of lithium hydroxide monohydrate is 0.292 kg / h, and the lithium recovery rate is 90%, which meets the judgment standard of GB / T 26008-2020 for battery-grade lithium hydroxide monohydrate.

[0192] Example 5

[0193] This embodiment provides a method for extracting lithium from solid materials, which differs from Embodiment 1 in that no stirring is performed during the mixing and reaction of liquid and solid materials.

[0194] In this embodiment, after primary and secondary calcination, the emission concentration of nitrogen oxides is 210 mg / Nm³. 3 The mass flow rate was 1.15 g / h, the phosphoric acid product yield was 0.444 kg / h with a purity of 99.7% and a phosphorus recovery rate of 90%. The iron oxide product yield was 0.161 kg / h with an iron recovery rate of 91%. The lithium hydroxide monohydrate product yield was 0.253 kg / h with a lithium overall recovery rate of 91%.

[0195] Comparative Example 1

[0196] This comparative example provides a method for extracting lithium from solid materials. The difference from Example 1 is that the liquid material is directly obtained from a mixed solution of lithium sulfate and sodium sulfate, rather than from recycled ternary lithium batteries.

[0197] After primary and secondary calcination, the nitrogen oxide emission concentration in this comparative example was 210 mg / Nm³. 3 The mass flow rate was 1.15 g / h, the phosphoric acid product yield was 0.444 kg / h with a purity of 99.7% and a phosphorus recovery rate of 90%. The iron oxide product yield was 0.154 kg / h with an iron recovery rate of 89%. The lithium hydroxide monohydrate product yield was 0.253 kg / h with a lithium overall recovery rate of 91%.

[0198] Table 1. Product Comparison in Each Example and Comparative Example

[0199]

[0200]

[0201] In Table 1, the leaching rate of iron in solid material = iron entering liquid product / iron contained in solid material; the leaching rate of lithium in solid material = lithium entering liquid product / lithium contained in solid material; the overall lithium recovery rate = lithium in lithium hydroxide product / lithium in battery recycled raw materials; the phosphorus recovery rate = phosphorus in phosphoric acid product / phosphorus contained in lithium iron phosphate battery recycled materials; and the iron recovery rate = iron in iron oxide product / iron contained in lithium iron phosphate battery recycled materials.

[0202] As can be seen from the data in Table 1 regarding the above embodiments and comparative examples, the lithium recovery rate can reach over 90% after using the lithium extraction method from solid materials provided in this application. This demonstrates that the method in this application can effectively extract lithium from solid materials. Furthermore, since iron and sulfur ions react fully during the mixing reaction, they do not accumulate. Therefore, it is not necessary to periodically discharge wastewater to control the content of impurity ions such as iron ions in the wastewater, thereby reducing wastewater discharge and facilitating the economical and efficient extraction of lithium from solid materials. Specifically, after mixing and reacting the solid and liquid materials, the iron (ferrous iron + ferric iron) content in the resulting liquid product is less than 1 ppm, indicating that the iron content in the liquid product is extremely low, essentially achieving effective separation of lithium and iron. Further processing of the liquid product to prepare lithium hydroxide yields lithium hydroxide and iron oxide products respectively.

[0203] Furthermore, the liquid and solid materials can originate from battery recyclables. For example, in the embodiments of this application, the liquid material can originate from ternary lithium battery recyclables, and the solid material can originate from lithium iron phosphate battery recyclables. By using the lithium extraction method described in the embodiments of this application to process the ternary lithium battery recyclables and lithium iron phosphate battery recyclables, lithium, iron, and phosphorus elements can be effectively extracted and separated. The phosphorus recovery rate can reach over 88%, and the iron recovery rate can reach over 90%. Corresponding lithium hydroxide products, iron oxide products, and phosphoric acid products can be prepared, achieving comprehensive utilization of battery recyclables.

[0204] Comparing the experimental data of Example 5 and Example 1, in Example 5, no stirring was performed during the mixing and reaction of the liquid and solid materials. In this case, the iron ions generated from the dissolution of iron oxide did not fully react with the sulfur ions in the liquid material, resulting in a small amount of iron ions remaining in the liquid product without precipitation, ultimately leading to a decrease in iron recovery rate. In contrast, in Example 1, the liquid and solid materials were mixed and reacted while stirring. This accelerated the reaction rate and ensured that the iron ions and sulfur ions fully reacted to form ferrous sulfide precipitate, allowing iron to enter the solid product and further improving the iron recovery rate.

[0205] Comparing the experimental data of Comparative Example 1 and Example 1, Comparative Example 1 directly used a mixed solution of lithium sulfate and sodium sulfate as the liquid material, meaning the liquid material did not contain sulfur ions. This resulted in some iron (ferrous iron + ferric iron) entering the liquid product, leading to a decrease in iron recovery rate. In contrast, Example 1 obtained the liquid material by processing the ternary lithium battery recycled material. The liquid material contained sulfur ions, which can react with ferrous iron / ferric iron to form ferrous sulfide precipitate, thereby reducing the iron content in the liquid product.

[0206] The technical features described above can be combined arbitrarily. Although not all possible combinations of these technical features are described, any combination of these technical features should be considered to be covered by this specification, provided that such combination does not contain contradictions.

[0207] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of this application, and are not intended to limit them. Although this application has been described in detail with reference to the foregoing embodiments, those skilled in the art should understand that modifications can still be made to the technical solutions described in the foregoing embodiments, or equivalent substitutions can be made to some or all of the technical features therein. Such modifications or substitutions do not cause the essence of the corresponding technical solutions to deviate from the scope of the technical solutions of the embodiments of this application.

Claims

1. A method for extracting lithium from solid materials, characterized in that, Includes the following steps: After mixing liquid and solid materials, solid and liquid products are obtained through solid-liquid separation. The liquid material contains water and sulfur ions, the solid material contains iron oxide and lithium oxide, the solid product contains iron oxide, and the liquid product contains lithium ions. The liquid material is obtained by pre-lithiation treatment of the first battery recycled material to obtain lithium extraction solution, which is then purified. The solid material is obtained by calcination of the second battery recycled material in an oxygen-containing atmosphere. Furthermore, during the mixing process, the pH value of the reaction solution is maintained at 5-8. The first type of battery recyclables includes at least one of lithium-ion battery recyclables, lithium-ion battery recyclables, and lithium-ion battery recyclables. The aforementioned lithium treatment includes acid leaching of the first battery recyclable to obtain a lithium extraction solution, or calcining the recyclable with an acid or reducing agent followed by leaching with a leaching agent to obtain a lithium extraction solution; wherein the leaching agent includes an acid, the acid includes sulfuric acid, and the reducing agent includes carbon and / or hydrogen. The purification process includes adding a precipitant to the lithium extraction solution to induce a precipitation reaction, followed by solid-liquid separation to obtain the liquid material. The precipitant comprises a sulfide, specifically sodium sulfide. The second type of battery recycling includes lithium iron phosphate battery recycling.

2. The method for extracting lithium from solid materials according to claim 1, characterized in that, The liquid-to-solid ratio of the liquid material to the solid material is 2L-6L:1kg.

3. The method for extracting lithium from solid materials according to claim 1, characterized in that, The mixing is carried out under stirring conditions, and the stirring rate is 120-150 r / min.

4. The method for extracting lithium from solid materials according to claim 1, characterized in that, The mixing time is 0.5-1.5 hours.

5. The method for extracting lithium from solid materials according to claim 1, characterized in that, The mixing temperature is 65-92℃.

6. The method for extracting lithium from solid materials according to claim 1, characterized in that, The sulfide ion content of the liquid material is 0.05-1 g / L.

7. The method for extracting lithium from solid materials according to claim 1, characterized in that, The sulfide ion content of the liquid product is 2.5-50 mg / L.

8. The method for extracting lithium from solid materials according to claim 1, characterized in that, The roasting temperature is 250-600℃; and / or the roasting time is 0.5-3h.

9. The method for extracting lithium from solid materials according to claim 1, characterized in that, The calcination temperature is in the range of 1060-1380℃.

10. The method for extracting lithium from solid materials according to claim 1, characterized in that, The calcination time is 6-30 minutes.

11. The method for extracting lithium from solid materials according to claim 10, characterized in that, The calcination time is 12-24 minutes.

12. The method for extracting lithium from solid materials according to claim 1, characterized in that, The calcination includes a first-stage calcination and a second-stage calcination performed sequentially, and the calcination temperature of the first-stage calcination is lower than that of the second-stage calcination.

13. The method for extracting lithium from solid materials according to claim 1, characterized in that, The excess gas coefficient of the oxygen-containing atmosphere is 1.35-1.

7.

14. The method for extracting lithium from solid materials according to claim 1, characterized in that, The mass ratio of the second battery recyclable to the first battery recyclable is 0.8-4:

1.

15. The method for extracting lithium from solid materials according to claim 14, characterized in that, The mass ratio of the second battery recyclable to the first battery recyclable is 2-3:

1.

16. The method for extracting lithium from solid materials according to claim 1, characterized in that, The lithium content of the liquid material is 3-16 g / L.

17. The method for extracting lithium from solid materials according to claim 1, characterized in that, The sodium content of the liquid material is 2.5-10 g / L.

18. The method for extracting lithium from solid materials according to claim 1, characterized in that, The pH value of the liquid material is 5-8.

19. The method for extracting lithium from solid materials according to claim 1, characterized in that, Before performing preliminary lithium treatment on the first battery recyclable, the method further includes: pyrolyzing the first battery recyclable to obtain pyrolysis post-material, and using the pyrolysis post-material for preliminary lithium treatment.

20. The method for extracting lithium from solid materials according to claim 1, characterized in that, The method further includes: adjusting the pH value of the liquid product to alkaline, then concentrating and cooling to crystallize to obtain a cooled crystallized liquid and a cooled crystallized product, and then post-processing the cooled crystallized liquid to obtain a lithium hydroxide product.

21. The method for extracting lithium from solid materials according to claim 20, characterized in that, The cooled crystallization product is then processed to obtain sodium sulfate.

22. The method for extracting lithium from solid materials according to claim 20, characterized in that, The temperature for cooling and crystallization is 0-20℃.

23. The method for extracting lithium from solid materials according to claim 20, characterized in that, The sodium sulfate mass percentage of the cooled crystallized liquid is ≤15%.

24. The method for extracting lithium from solid materials according to claim 20, characterized in that, The lithium content of the cooled crystallized liquid is ≥5g / L.

25. The method for extracting lithium from solid materials according to claim 20, characterized in that, Before concentration, alkali is added to the liquid product to adjust the pH to 13-14.

5.

26. A system for the method of extracting lithium from a solid material according to any one of claims 1-25, characterized in that, It includes a calcination system, a lithium precursor system, a purification system, and a mixing system, wherein the calcination system and the mixing system are connected, and the lithium precursor system is sequentially connected to the purification system and the mixing system; The calcination system is used to calcine the second battery recycled material to obtain solid material; The pre-lithiation system and the purification system are used to sequentially process the first battery recycled material with pre-lithiation and purification to obtain liquid material. The mixing system is used to mix liquid and solid materials, and then separate the liquid and solid materials to obtain a solid product containing iron oxide and a liquid product containing lithium ions.

27. The system for extracting lithium from solid materials according to claim 26, characterized in that, The calcination system includes a primary calcination system and a secondary calcination system, wherein the primary calcination system is sequentially connected to the secondary calcination system and the mixing system; The primary calcination system and the secondary calcination system are used to process the second battery recycled material through primary calcination and secondary calcination to obtain solid material.

28. The system for extracting lithium from solid materials according to claim 26, characterized in that, It also includes a pyrolysis system connected to the prerequisite lithium system, the pyrolysis system being used to send the first battery recycled material into the prerequisite lithium system after pyrolysis treatment.

29. The system for extracting lithium from solid materials according to claim 26, characterized in that, It also includes a concentration system, a cooling crystallization system, and a post-processing system, wherein the mixing system is connected in sequence to the concentration system, the cooling crystallization system, and the post-processing system; The concentration system and the cooling crystallization system are used to concentrate and cool crystallize the liquid product obtained from the mixing system in sequence to obtain a cooled crystallized liquid and a cooled crystallized product. The post-processing system is used to process the cooled crystallized liquid to obtain lithium hydroxide product.

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