Method for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide

Abstract

The present invention discloses a method for preparing high-purity lithium hydroxide by recovering lithium from waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials, comprising the following steps: (1) mixing waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials with oxalic acid, and then performing a roasting process to obtain a roasting product; (2) grinding the roasting product, leaching it once, and filtering it to obtain a filtrate 1 and a filter residue 1; (3) adding alkali to the filtrate 1 for caustic treatment, filtering it again, and collecting the filtrate 2; (4) evaporating and concentrating the filtrate 2, and crystallizing it, and collecting the crystals to obtain high-purity lithium hydroxide. The method for preparing high-purity lithium oxalate by recovering lithium from waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials of the present invention has the advantages of short process, low production cost, strong raw material applicability, etc., and the production process does not produce any toxic or harmful gas waste residue, which is safer and more environmentally friendly.

Description

Technical Field

[0001] The invention belongs to the field of comprehensive recovery of lithium batteries, and in particular relates to a method for recovering lithium from lithium batteries. Background Art

[0002] Waste lithium battery dismantling is mainly the product of dismantling and sorting of scrapped lithium-ion batteries. It is a mixture of lithium-ion battery positive and negative electrodes. The main components are lithium nickel cobalt manganese oxide, graphite powder, copper powder, aluminum powder, binder and electrolyte, etc. The binder and electrolyte are mainly fluorine compounds. Waste lithium battery positive electrode materials are mainly unqualified products in the positive electrode production process, unqualified products and scraps produced during coating, etc. The main components are lithium nickel cobalt manganese oxide, aluminum powder and binder. The above-mentioned waste lithium battery dismantling and waste lithium battery positive electrode materials all contain a certain amount of lithium, and it is of great value to recover lithium from them.

[0003] In the existing technology, lithium recovery from waste lithium battery dismantling and waste lithium battery positive electrode materials is mainly divided into pyrometallurgical lithium extraction and wet lithium extraction. Pyrometallurgical lithium extraction uses hydrogen, natural gas and carbon powder as reducing agents to extract lithium after reduction reaction in the reduction furnace; wet lithium extraction uses strong acids such as sulfuric acid for leaching and then recovers lithium from wastewater after a series of impurity removal and extraction of nickel, cobalt and manganese. The pyrometallurgical lithium extraction process requires strict control of the reducing atmosphere, and the wet lithium extraction process is long, the impurity content of the leaching solution is high, and the impurity removal process is easy to carry lithium, which requires complex washing and recovery; in addition, the purity and yield of lithium products from traditional pyrometallurgical and wet lithium extraction are not high, and they are generally crude lithium salts, and the lithium yield is about 85%. Summary of the invention

[0004] The technical problem to be solved by the present invention is to overcome the deficiencies and defects mentioned in the above background technology, and provide a method for recovering lithium from waste lithium battery dismantling and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide, which has low impurity content in the leachate, short process, high product purity and yield, and strong raw material adaptability. In order to solve the above technical problems, the technical solution proposed by the present invention is:

[0005] A method for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide comprises the following steps:

[0006] (1) Dismantling waste lithium batteries and / or waste lithium battery positive electrode materials are mixed with oxalic acid, and then roasted once to obtain a primary roasting product.

[0007] (2) The primary roasting product obtained in step (1) is ground, leached and filtered to obtain a filtrate 1 and a filter residue 1.

[0008] (3) adding alkali to the filtrate 1 obtained in step (2) for caustic treatment, filtering again, and collecting the filtrate 2.

[0009] (4) The filtrate 2 obtained in step (3) is subjected to evaporation concentration and crystallization treatment, and the crystals are collected to obtain high-purity lithium hydroxide. The crystallization mother liquor can be further subjected to evaporation concentration and crystallization treatment, and the crystals can be collected to obtain crude lithium hydroxide. The crystallization mother liquor in this process can be returned to the evaporation concentration step.

[0010] In the above method for preparing high-purity lithium hydroxide, preferably, the waste lithium battery dismantling products and the lithium battery positive electrode materials are first subjected to low-temperature sorting treatment, and the low-temperature sorting treatment is to vibrate and screen the waste lithium battery dismantling products and the lithium battery positive electrode materials at 250-350°C, and the screening particle size is controlled at 100-150 meshes, collect the undersieve materials, and mix them with ammonium oxalate; collect the oversieve materials, crush them and then sieve them, and the screening particle size is controlled at 100-150 meshes, collect the undersieve materials, and mix them with ammonium oxalate.

[0011] In the above method for preparing high-purity lithium hydroxide, preferably, when waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials are used as raw materials and mixed with oxalic acid, the mass ratio of oxalic acid to raw materials is controlled to be (2-6):1, and the mixing time is 30-90min; during the first roasting, the roasting temperature is controlled to be 490-600°C, and the roasting time is 120-240min.

[0012] In the above method for preparing high-purity lithium hydroxide, preferably, the waste lithium battery dismantling material contains lithium-containing positive electrode powder, carbon-containing negative electrode powder, fluorine-containing binder and fluorine-containing electrolyte, and the waste lithium battery positive electrode material contains lithium-containing positive electrode powder and fluorine-containing binder; calcium lignin sulfonate is also added when oxalic acid is added, and the amount of calcium lignin sulfonate added controls the mass ratio of calcium lignin sulfonate to raw material to be (0.5-1):1.

[0013] In the above method for preparing high-purity lithium hydroxide, preferably, during the grinding, all the materials after grinding are controlled to pass through a 100-mesh sieve; during the primary leaching, pure water (or filtrate 3) is used for leaching, and the leaching time is 120-180 minutes; the filtrate 1 is first allowed to stand and filtered before the subsequent acidity adjustment process, and the standing is 48-72 hours at room temperature.

[0014] In the above method for preparing high-purity lithium hydroxide, preferably, the alkali added during the alkali causticization treatment is at least one of sodium hydroxide, calcium hydroxide or potassium hydroxide, and the reaction temperature is controlled to be 90-95° C. and the reaction time is 120-240 min.

[0015] In the above method for preparing high-purity lithium hydroxide, preferably, sulfuric acid is added to the filter residue 1 obtained in step (2) for secondary leaching, and filtrate 3 and filter residue 3 are obtained by filtration. The filtrate 3 is collected in the primary leaching process (can be used as the base liquid of the primary leaching), and the filter residue 3 is mixed with oxalic acid for secondary roasting to obtain a secondary roasting product, and the secondary roasting product is collected in the grinding process.

[0016] In the above method for preparing high-purity lithium hydroxide, preferably, when sulfuric acid is added for secondary leaching, the leaching time is 120-180 min, and the amount of sulfuric acid added controls the pH value of the reaction endpoint to be 2.5-3.5.

[0017] In the above method for preparing high-purity lithium hydroxide, preferably, when the filter residue 3 is mixed with oxalic acid for secondary calcination, the mass ratio of ammonium oxalate to the filter residue 3 is controlled to be (0.5-1):1, and the mixing time is 30-90 min; during the secondary calcination, the calcination temperature is controlled to be 490-600°C, and the calcination time is 120-240 min.

[0018] In the above method for preparing high-purity lithium hydroxide, preferably, calcium lignin sulfonate is also added when the filter residue 3 is mixed with oxalic acid, and the amount of calcium lignin sulfonate added controls the mass ratio of calcium lignin sulfonate to the filter residue 3 to be (0.2-0.5):1.

[0019] In the above method for preparing high-purity lithium hydroxide, preferably, the filtrate 1 obtained in step (2) is sequentially subjected to sulfation treatment, precipitation treatment, fine filtration, evaporation concentration, and crystallization treatment, and the crystals are collected to obtain high-purity lithium sulfate, wherein the sulfation treatment is to add sulfuric acid at room temperature, adjust the pH value to 0.5-1.5, and react for 60-120 minutes, and the precipitation treatment is to add lithium hydroxide at room temperature, adjust the pH value to 6.5-7.5, and react for 60-120 minutes. The above crystallization mother liquor can be returned to the static filtration process to recover the lithium ions therein.

[0020] In the above method for preparing high-purity lithium hydroxide, preferably, the filtrate 2 obtained in step (3) is subjected to carbonization treatment, and the solid phase is filtered and collected to obtain high-purity lithium carbonate, and the carbonization treatment is to pass carbon dioxide into the filtrate 2. The mother liquor obtained by filtration is evaporated, concentrated, and crystallized, and the crystals are collected to obtain crude lithium carbonate. The crystallization mother liquor in this process can be returned to the evaporation and concentration step.

[0021] The present invention first sorts the waste lithium battery dismantling material and / or the waste lithium battery positive electrode material, that is, low-temperature screening and sorting, and the sorted powder is mixed with oxalic acid in a certain proportion. The mixed materials are roasted in a roasting furnace, and the roasted materials are ground. The powder after grinding is leached twice, and the filtrate of the second leaching can be used as the bottom liquid of the first leaching. The slag after the second leaching is mixed with oxalic acid and then roasted again. The roasted materials are incorporated into the grinding process. The filtrate of the first leaching is statically filtered, that is, filtered after standing and clarifying, and the filtrate is causticized with crude lithium hydroxide or sodium hydroxide. The causticized liquid is concentrated, crystallized, and centrifuged after fine filtration to obtain high-purity lithium hydroxide. The causticized liquid after fine filtration is carbonized by carbon dioxide, concentrated, crystallized, and centrifuged to obtain high-purity lithium carbonate. Sulfuric acid is added to the first leaching liquid for sulfation, and lithium is completely converted into lithium sulfate. Lithium hydroxide is used to adjust the pH value to neutralize excess sulfuric acid. The solution is concentrated, crystallized, and separated after fine filtration to obtain high-purity lithium sulfate.

[0022] Compared with the prior art, the advantages of the present invention are:

[0023] 1. The method of the present invention for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium oxalate utilizes oxalic acid and waste materials for mixed roasting, and lithium can be selectively leached directly from the raw materials after leaching. The impurity content in the leachate is low, which is more conducive to the subsequent preparation of high-purity lithium hydroxide and is beneficial to improving the purity and yield of the product.

[0024] 2. The method of the present invention for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium oxalate has the advantages of short process, low production cost, strong raw material applicability, etc., and the production process does not produce any toxic or harmful gas waste, which is safer and more environmentally friendly. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] 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 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.

[0026] Figure 1 The present invention is a process flow chart of the method for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide. DETAILED DESCRIPTION

[0027] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively and meticulously below in conjunction with the accompanying drawings and preferred embodiments of the present invention, but the protection scope of the present invention is not limited to the following specific embodiments.

[0028] Unless otherwise defined, all the professional terms used below have the same meanings as those generally understood by those skilled in the art. The professional terms used herein are only for the purpose of describing specific embodiments and are not intended to limit the scope of protection of the present invention.

[0029] Unless otherwise specified, various raw materials, reagents, instruments and equipment used in the present invention can be purchased from the market or prepared by existing methods.

[0030] like Figure 1 FIG. 1 is a process flow chart of a method for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide according to the present invention. Figure 1 The specific steps and effects of each process step are explained below:

[0031] Raw materials: The dismantled waste lithium battery contains lithium-containing positive electrode powder, carbon-containing negative electrode powder, fluorine-containing binder and fluorine-containing electrolyte. The waste lithium battery positive electrode material contains lithium-containing positive electrode powder and fluorine-containing binder.

[0032] Sorting: Under the condition of 250-350℃, the raw materials are vibrated and sieved, and the sieved particle size is controlled at 100-150 mesh (100 mesh to below 150 mesh, such as 100 mesh sieve, 120 mesh sieve or 150 mesh sieve). The sieved material needs to be crushed again and sieved, and the sieved material and the sieved material are combined into the next process. The purpose of sorting is to separate volatile substances and remove moisture under low temperature conditions, and to sieve and separate larger particles and agglomerated materials while drying.

[0033] Batching and mixing: the screened material after sorting and screening is mixed with oxalic acid, the mass ratio of screened material to oxalic acid is (2-6):1, and the mixing time is 30-90 minutes. Mixing is to mix the secondary leached residue 3 with oxalic acid, the mass ratio of oxalic acid to residue 3 is (0.2-0.5):1, and the mixing time is 30-90 minutes.

[0034] Since the raw materials contain fluorine, in order to avoid the combination of lithium and fluorine to form lithium fluoride and affect the subsequent treatment, calcium lignin xanthate (C 20 H 24 CaO 10 S 2 ), specifically, the mass ratio of calcium lignin sulfonate to the undersize is (0.5-1):1, and the mass ratio of calcium lignin sulfonate to the filter residue 3 is (0.2-0.5):1.

[0035] Calcium lignin sulfonate is a multi-component high molecular polymer anionic surfactant, non-toxic, light yellow to dark brown powder, slightly aromatic, with strong dispersibility, adhesion, chelation, and can contain up to 30% reducing sugar. It undergoes thermal decomposition reaction at 300°C to generate elemental carbon, calcium oxide, sulfur dioxide and water, and has strong reducing properties. By adding calcium lignin sulfonate, its main function is that the decomposition product reacts with the fluorine in the raw material to generate insoluble fluoride salts to reduce the interference of fluoride ions on lithium ions, and its decomposition products can work together with oxalic acid.

[0036] When the amount of oxalic acid is too much, the carbon monoxide produced by decomposition will overflow, increasing the difficulty of tail gas treatment and posing the risk of environmental pollution; when the amount is too little, the amount of reducing agent is insufficient and the degree of reduction is insufficient, affecting the leaching rate of lithium. When the amount of calcium lignin sulfonate is too much, the sulfur dioxide produced by decomposition will overflow, increasing the difficulty of tail gas treatment and posing the risk of environmental pollution; when the amount is too little, the amount of calcium is insufficient and cannot completely combine with fluorine, resulting in lithium fluoride in the water extract.

[0037] Calcination: Calcination is divided into batching and mixing. Batch roasting is the primary roasting, and mixed roasting is the secondary roasting after the secondary leaching residue is mixed with oxalic acid. The process is carried out in a calcining furnace, with a controlled temperature of 490-600℃ and a reaction time of 120-240 minutes. The reaction equation in the furnace is as follows:

[0038] 2LiCoO 2 +3H 2 C 2 O 4 =2CoC 2 O 4 +Li 2 C 2 O 4 +3H 2 O+1 / 2O 2 ↑;

[0039] 2LiCoO 2 +H 2 C 2 O 4 =Co 2 O 3 +Li 2 C 2 O 4 +H 2 O;

[0040] 2LiNiO 2 +3H 2 C 2 O 4 =2NiC 2 O 4 +Li 2 C2 O 4 +3H 2 O+1 / 2O 2 ↑;

[0041] 2LiNiO 2 +H 2 C 2 O 4 =Ni 2 O 3 + Li 2 C 2 O 4 +H 2 O;

[0042] 2LiMn 2 O 4 +5H 2 C 2 O 4 =4MnC 2 O 4 + Li 2 C 2 O 4 +5H 2 O+1 / 2O 2 ↑;

[0043] 4LiCoO 2 +3C=4Co+2Li 2 CO 3 +CO 2 ↑;

[0044] 4LiNiO 2 +3C=4Ni+2Li 2 CO 3 +CO 2 ↑;

[0045] 2LiC 2 O 4 =Li 2 O+CO↑+3CO 2 ↑;

[0046] A 2 C 2 O 4 =CO↑+CO 2 ↑+H 2 O;

[0047] 2LiCoO 2 +CO=2CoO+Li 2 CO 3 ;

[0048] 2LiNiO 2+CO=2NiO+Li 2 CO 3 ;

[0049] 2LiMn 2 O 4 +CO=4MnO+Li 2 CO 3 +O 2 ↑;

[0050] CaO+2F - =O 2- +CaF 2 ;

[0051] 2LiCoO 2 +SO 2 =2CoO+Li 2 SO 4 ;

[0052] 2LiNiO 2 +SO 2 =2NiO+Li 2 SO 4 ;

[0053] 2LiMn 2 O 4 +SO 2 =4MnO+Li 2 SO 4 +O 2 ↑.

[0054] The roasting process begins with a short reaction between oxalic acid and the raw materials to produce a small amount of lithium oxalate. This is followed by the pyrolysis of oxalic acid (which begins to decompose at 195°C) to produce reducing carbon monoxide (CO) to reduce the raw materials, followed by the pyrolysis of calcium lignin sulfonate (which begins to decompose at 300°C) to produce sulfur dioxide (SO 2 ) and carbon (C) and calcium oxide (CaO). The carbon generated is highly active elemental carbon and has a strong reducing effect together with sulfur dioxide. Calcium oxide reacts with fluorine in the raw materials to form insoluble calcium fluoride. The lithium oxalate initially generated by the final reaction will completely decompose into lithium oxide when heated.

[0055] During the roasting process, if the roasting temperature is too low, the lithium oxalate produced cannot undergo a decomposition reaction, and lithium oxalate will be contained in the water during leaching, and a pure lithium sulfate solution cannot be obtained. When the roasting temperature is too high, the material agglomerates more, which increases the difficulty of crushing and increases energy consumption. If the roasting time is too short, the reaction is incomplete, resulting in a low lithium leaching rate, and the added materials do not react and enter the leaching solution, causing an increase in impurities; if the roasting time is too long, it mainly causes an increase in energy consumption, the degree of material agglomeration and hardening increases, and the difficulty of crushing increases.

[0056] Grinding: After the roasted material is cooled, it is ground, and the particle size of the ground material is controlled to be 100% through a 100-mesh sieve. Grinding is beneficial to leaching on the one hand, and filtering on the other.

[0057] Leaching: Leaching can be divided into primary leaching and secondary leaching. In primary leaching, pure water (or the filtrate of secondary leaching) is used to carry out leaching reaction with the ground material in a reaction tank at room temperature, and the leaching time is 120-180 minutes. In secondary leaching, sulfuric acid is used to carry out leaching reaction with the filter residue of primary leaching in a reaction tank at room temperature, and the leaching time is 120-180 minutes, and the end point pH value is 3.5-4.5. In the primary leaching process, lithium oxide dissolves in water to form lithium hydroxide, and in the secondary leaching, lithium carbonate reacts with sulfuric acid to form lithium sulfate. The reaction equation is as follows:

[0058] Li 2 O+H 2 O = 2LiOH;

[0059] Li 2 CO 3 +H 2 SO 4 =Li 2 SO 4 +H 2 O+CO 2 ↑;

[0060] 2LiOH+H 2 SO 4 =Li 2 SO 4 +2H 2 O.

[0061] Static filtration: The primary leaching filtrate is filtered after being left to stand for 48-72 hours at room temperature. On the one hand, the suspended fine particles can be naturally settled, and on the other hand, the fine particles can aggregate and grow during the standing process, and the particle size can be increased.

[0062] Causticization: The alkali added to the solution after static filtration for causticization treatment is at least one of sodium hydroxide, calcium hydroxide or potassium hydroxide, and the reaction temperature is controlled to be 90-95°C, the reaction time is 120-240min, and the amount of alkali added is 1.1-1.5 times the theoretical consumption of lithium and hydroxide reaction; the reaction equation is as follows:

[0063] 2NaOH+Li 2 SO 4 =2LiOH+Na 2 SO 4 .

[0064] Sulfate: Sulfuric acid is added to the primary leaching filtrate at room temperature to adjust the pH value to 0.5-1.5. The reaction time is 60-120 minutes. The purpose is to completely convert lithium hydroxide and lithium carbonate in the solution into lithium sulfate.

[0065] Adjustment and precipitation: After sulfation, lithium hydroxide is added to the solution at room temperature to adjust the pH value to 6.5-7.5. The reaction time is 60-120 minutes. The purpose is to convert the excess sulfuric acid in the solution into lithium sulfate and remove impurities. The solution after adjustment and precipitation is finely filtered and then enters the evaporation and concentration process.

[0066] Carbonization: Carbon dioxide is introduced into the causticized liquid after fine filtration in the carbonization equipment to convert lithium hydroxide into lithium carbonate. The reaction equation is as follows:

[0067] 2LiOH+CO 2 =Li 2 CO 3 +H 2 O.

[0068] Evaporation concentration: The purpose of evaporation concentration is to increase the concentration of lithium ions and make them supersaturated. When obvious crystals are produced during the concentration process, the material can be discharged for crystallization.

[0069] Crystallization: By lowering the temperature, the supersaturated lithium solution will precipitate the corresponding lithium crystals. The crystallization end temperature is controlled at 20-35℃. Too low a crystallization temperature will increase time and energy consumption.

[0070] Centrifugal filtration: After crystallization, centrifugal filtration is used to obtain the corresponding crystals and mother liquor. The lithium sulfate mother liquor can be incorporated into the static filtration process, and the lithium hydroxide and lithium carbonate mother liquors are directly evaporated, concentrated, crystallized, and centrifuged to obtain the corresponding crude products. The crude products are used as production raw materials after sodium removal.

[0071] Embodiment 1:

[0072] A method for recovering lithium from dismantled waste lithium batteries to prepare high-purity lithium hydroxide, lithium carbonate and lithium sulfate, comprising the following steps:

[0073] Take 500kg of material, including the following components by mass: 13.43% nickel, 7.31% cobalt, 11.01% manganese, 1.33% fluorine, 2.76% aluminum, and 17.68% carbon. Dry at 300℃, pass the dried material through a 150-mesh sieve, and obtain 493kg of undersize and 7kg of oversize. The oversize is further crushed and sieved (can be mixed with the next batch of materials). Take the undersize and analyze it to find that it contains 3.86% lithium. Add 990kg oxalic acid and 295kg calcium lignin sulfonate and mix for 60 minutes. After mixing, put the material into a calcining furnace and react at 600℃ for 240 minutes. After the calcined material is cooled, grind it and sieve it. The oversize is returned and ground until it is completely sieved through a 100-mesh sieve.

[0074] 3000L of pure water was added to the reactor, and the ground material was put in for primary leaching. The reaction lasted for 180 minutes, and the mixture was filtered to obtain 3160L of primary filtrate. 2000L of pure water was added to the reactor, and the primary leaching residue was put in. Sulfuric acid was added to control the pH value to 3.0 for secondary leaching. The reaction lasted for 120 minutes, and the mixture was filtered to obtain 2380L of secondary filtrate (the reason for the increase in volume is that the water brought by steam heating may be introduced into the leaching process, the same below) and 519kg of secondary filter residue. The secondary filtrate can be used for the next batch of materials as the leachate for the primary leaching, and there is no loss of lithium at this time. 300kg of oxalic acid and 100kg of calcium lignin sulfonate were added to the secondary filter residue and mixed for 60 minutes. The mixture was put into a calcining furnace and reacted at 600°C for 240 minutes. After the calcined material was cooled, the powder was sieved, and the sieved material was returned to continue grinding until it was completely sieved through a 100-mesh sieve. The ground material continued the primary leaching process, and the filtrate could be used as the leaching liquid for the next batch of materials, with no loss of lithium at this time. At the same time, 491 kg of filter residue was obtained, and the analysis showed that it contained 0.11% lithium. After two roastings and two leachings, the lithium yield was 97.16%.

[0075] The first leaching solution of the first roasting was 3160L, and the lithium content was 5.60g / L. Take 2000L of the first leaching solution of the first roasting, let it stand for 48 hours and then filter it. The filter surface turns yellow but there is no stacked filter residue. The filtrate is added to the reactor, and 1.5 times the theoretical amount (329.9kg of liquid alkali with a mass content of 30%) of sodium hydroxide is added for causticization. After reacting at 95°C for 240 minutes, fine filtration is performed. 5.1kg of filter residue is obtained, and the lithium content is 0.47%, and the lithium yield is 99.8%. The results of the filtrate analysis are shown in Table 1 below:

[0076] Table 1: Analysis and test results of filtrate (unit: mg / L)

[0077] lithium nickel cobalt manganese iron copper aluminum calcium magnesium Zinc 5583 3.31 2.71 2.13 2.11 1.11 5.45 3.17 3.87 1.12

[0078] 1000L of refined filtrate was concentrated under air isolation, crystallized at 30°C, and filtered to obtain lithium hydroxide and mother liquor. The test results of lithium hydroxide after drying are shown in Table 2 below:

[0079] Table 2: Detection results of lithium hydroxide (unit: ppm)

[0080]

[0081] The mother liquor is completely concentrated and crystallized to obtain crude lithium hydroxide for standby use. The lithium yield of lithium hydroxide production is 96.97%.

[0082] The other half of 1000L of refined filtrate was carbonized and concentrated by passing carbon dioxide, crystallized at 30°C, and filtered to obtain lithium carbonate and mother liquor. The test results after drying lithium carbonate are shown in Table 3 below:

[0083] Table 3: Test results of lithium carbonate (unit: ppm)

[0084]

[0085] The mother liquor is completely concentrated and crystallized to obtain crude lithium carbonate for standby use. The lithium yield of lithium hydroxide production is 96.97%.

[0086] Take 1160L of the first leaching solution from the first roasting, add sulfuric acid to adjust the pH to 1.0, and react for 120 minutes. After the reaction is completed, add lithium hydroxide, adjust the pH to 7.2, and react for 120 minutes before fine filtration. Obtain 17.5kg of filter residue, which contains 0.34% lithium and 99.1% lithium yield. The filtrate is concentrated, filtered after crystallization at 30°C, and lithium sulfate and mother liquor are obtained. The drying analysis results of lithium sulfate are shown in Table 4 below:

[0087] Table 4: Analysis and test results of lithium sulfate (unit: ppm)

[0088]

[0089] All the mother liquor is returned to the static filtration process, there is no loss of lithium, and the lithium yield of lithium sulfate production is 96.29%.

[0090] Embodiment 2:

[0091] A method for recovering lithium from waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide, lithium carbonate and lithium sulfate, comprising the following steps:

[0092] Take 300kg of material, including the following components by mass: 25.77% nickel, 8.14% cobalt, 15.11% manganese, 0.83% fluorine, 1.27% aluminum, and 2.11% carbon. Dry at 350℃, pass the dried material through a 150-mesh sieve, and obtain 297.3kg of undersize and 2.7kg of oversize. The oversize is further crushed and sieved (can be mixed with the next batch of materials). Take the undersize and analyze it to find that it contains 6.33% lithium. Add 1200kg oxalic acid and 165kg calcium lignin sulfonate and mix for 60 minutes. After mixing, put the material into a calcining furnace and react at 600℃ for 240 minutes. After the calcined material is cooled, grind it and sieve it. The oversize is returned and ground until it is completely sieved through a 100-mesh sieve.

[0093] 3500L of pure water was added to the reactor, and the ground material was put in for primary leaching. The reaction lasted for 180 minutes, and the material was filtered to obtain 3410L of primary filtrate. 2000L of pure water was added to the reactor, and the primary leaching residue was put in. Sulfuric acid was added to control the pH value to 2.5 for secondary leaching. The reaction lasted for 120 minutes, and the secondary filtrate was 2250L and 324.8kg of secondary filter residue were obtained. The secondary filtrate can be used for the next batch of materials as the leachate for the primary leaching, and there is no loss of lithium at this time. 185kg of oxalic acid and 90kg of calcium lignin sulfonate were added to the secondary filter residue and mixed for 60 minutes. The mixture was put into a calcining furnace and reacted at 550°C for 240 minutes. After the calcined material was cooled, the powder was sieved, and the material on the sieve was returned to continue grinding until it was completely sieved through a 100-mesh sieve. The material after grinding continued the primary leaching process, and the filtrate could be used for the next batch of materials as the leachate for the primary leaching. At this time, there was no loss of lithium, and 321.6kg of filter residue was obtained. The analysis showed that the lithium content was 0.17%. After two roastings and two leachings, the lithium yield is 97.09%.

[0094] The first leaching solution of the first roasting was 3410L, and the lithium content was 4.97g / L. Take 2000L of the first leaching solution of the first roasting, let it stand for 56 hours and then filter. The filter surface turns yellow but there is no stacked filter residue. The filtrate is added to the reactor, and 1.3 times the theoretical amount (1.3 times is 253.7kg of liquid alkali with a mass content of 30%) of sodium hydroxide is added for causticization. After reacting at 95°C for 240 minutes, fine filtration is performed. 3.6kg of filter residue is obtained, and the lithium content is 0.59% and the lithium yield is 99.8%. The results of the filtrate analysis are shown in Table 5 below:

[0095] Table 5: Analytical test results of filtrate (unit: mg / L)

[0096] lithium nickel cobalt manganese iron copper aluminum calcium magnesium Zinc 4950 1.01 1.63 1.10 2.19 0.74 6.48 1.33 1.64 0.94

[0097] 1000L of refined filtrate was concentrated under air isolation, crystallized at 27°C, and filtered to obtain lithium hydroxide and mother liquor. The test results of lithium hydroxide after drying are shown in Table 6 below:

[0098] Table 6: Detection results of lithium hydroxide (unit: ppm)

[0099]

[0100] The mother liquor is completely concentrated and crystallized to obtain crude lithium hydroxide for standby use. The lithium yield of lithium hydroxide production is 96.90%.

[0101] The other half of 1000L of the refined filtrate was carbonized and concentrated by passing carbon dioxide, crystallized at 27°C, and filtered to obtain lithium carbonate and mother liquor. The test results after drying the lithium carbonate are shown in Table 7 below:

[0102] Table 7: Test results of lithium carbonate (unit: ppm)

[0103]

[0104] The mother liquor is completely concentrated and crystallized to obtain crude lithium carbonate for standby use. The lithium yield of lithium hydroxide production is 96.90%.

[0105] Take 1410L of the first leaching solution from the first roasting, add sulfuric acid to adjust the pH to 1.0, and react for 120 minutes. After the reaction is completed, add lithium hydroxide, adjust the pH to 7.0, and react for 120 minutes before fine filtration. Obtain 21.3kg of filter residue, which contains 0.49% lithium and 98.5% lithium yield. The filtrate is concentrated, filtered after crystallization at 27°C, and lithium sulfate and mother liquor are obtained. The drying analysis results of lithium sulfate are shown in Table 8 below:

[0106] Table 8: Analysis and test results of lithium sulfate (unit: ppm)

[0107]

[0108] All the mother liquor is returned to the static filtration process, there is no loss of lithium, and the lithium yield of lithium sulfate production is 95.63%.

[0109] Embodiment 3:

[0110] A method for recovering lithium from dismantled waste lithium batteries to prepare high-purity lithium hydroxide, lithium carbonate and lithium sulfate, comprising the following steps:

[0111] Take 500kg of material, including the following components by mass: 8.15% nickel, 5.97% cobalt, 14.35% manganese, 3.51% fluorine, 1.90% aluminum, and 33.25% carbon. Dry at 350℃, pass the dried material through a 150-mesh sieve, and obtain 467.3kg of undersize and 32.7kg of oversize. The oversize is further crushed and sieved (can be mixed with the next batch of materials). Take the undersize and analyze it to find that it contains 2.19% lithium. Add 950kg oxalic acid and 240kg calcium lignin sulfonate and mix for 60 minutes. After mixing, put the material into a calcining furnace at 500℃ and react for 240 minutes. After the calcined material is cooled, grind it and sieve it. Return the oversize to continue grinding until it completely passes through a 100-mesh sieve.

[0112] 2000L of pure water was added to the reactor, and the ground material was put in for primary leaching. The reaction lasted for 180 minutes, and the material was filtered to obtain 1940L of primary filtrate. 2000L of pure water was added to the reactor, and the primary leaching residue was put in. Sulfuric acid was added to control the pH value to 2.5 for secondary leaching. The reaction lasted for 120 minutes, and the secondary filtrate was 2090L and 537.4kg of secondary filter residue were obtained. The secondary filtrate can be used for the next batch of materials as the leachate for the primary leaching, and there is no loss of lithium at this time. 285kg of oxalic acid and 115kg of calcium lignin sulfonate were added to the secondary filter residue and mixed for 60 minutes. The mixture was put into a calcining furnace and reacted at 500°C for 240 minutes. After the calcined material was cooled, the powder was sieved, and the material on the sieve was returned to continue grinding until it was completely sieved through a 100-mesh sieve. The material after grinding continued the primary leaching process, and the filtrate can be used for the next batch of materials as the leachate for the primary leaching, and there is no loss of lithium at this time. At the same time, 522.3kg of filter residue was obtained, and the analysis showed that it contained 0.21% lithium. After two roastings and two leachings, the lithium yield was 89.28%.

[0113] The first leaching solution of the first roasting was 1940L, and the lithium content was 3.69g / L. Take 1400L of the first leaching solution of the first roasting, let it stand for 48 hours and then filter. The filter surface turns yellow but there is no stacked filter residue. The filtrate is added to the reactor, and 1.2 times the theoretical amount (1.2 times is 121.7kg of liquid alkali with a mass content of 30%) of sodium hydroxide is added for causticization. After reacting at 95°C for 240 minutes, fine filtration is performed. 1.3kg of filter residue is obtained, and the lithium content is 0.31%, and the lithium yield is 99.9%. The results of the filtrate analysis are shown in Table 9 below:

[0114] Table 9: Analytical test results of filtrate (unit: mg / L)

[0115] lithium nickel cobalt manganese iron copper aluminum calcium magnesium Zinc 3690 1.93 1.07 2.13 1.22 0.98 7.55 3.49 3.27 2.14

[0116] 700L of refined filtrate was concentrated under air isolation, crystallized at 30°C, and filtered to obtain lithium hydroxide and mother liquor. The test results of lithium hydroxide after drying are shown in Table 10 below:

[0117] Table 10: Detection results of lithium hydroxide (unit: ppm)

[0118]

[0119] The mother liquor is completely concentrated and crystallized to obtain crude lithium hydroxide for standby use. The lithium yield of lithium hydroxide production is 89.19%.

[0120] The other half of 700L of the refined filtrate was carbonized and concentrated by passing carbon dioxide, crystallized at 30°C, and filtered to obtain lithium carbonate and mother liquor. The test results after drying the lithium carbonate are shown in Table 11 below:

[0121] Table 11: Test results of lithium carbonate (unit: ppm)

[0122]

[0123] The mother liquor is completely concentrated and crystallized to obtain crude lithium carbonate for standby use. The lithium yield of lithium hydroxide production is 89.19%.

[0124] Take 540L of the first leaching solution from the first roasting, add sulfuric acid to adjust the pH to 1.5, and react for 120 minutes. After the reaction is completed, add lithium hydroxide, adjust the pH to 7.2, and react for 120 minutes before fine filtration. Obtain 27.8kg of filter residue, which contains 0.35% lithium and 95.1% lithium yield. The filtrate is concentrated, filtered after crystallization at 30°C, and lithium sulfate and mother liquor are obtained. The drying analysis results of lithium sulfate are shown in Table 12 below:

[0125] Table 12: Analysis and test results of lithium sulfate (unit: ppm)

[0126]

[0127] All mother liquor is returned to the static filtration process, no lithium is lost, and the lithium yield of lithium sulfate production is 84.92%. The reason for the low lithium yield in this embodiment is that the raw material contains low lithium.

[0128] Embodiment 4:

[0129] A method for recovering lithium from dismantled waste lithium batteries to prepare high-purity lithium hydroxide, lithium carbonate and lithium sulfate, comprising the following steps:

[0130] Take 300kg of material, including the following components by mass: 23.01% nickel, 6.23% cobalt, 18.31% manganese, 1.01% fluorine, 0.94% aluminum, and 9.45% carbon. Dry at 350℃, pass the dried material through a 150-mesh sieve, and obtain 295.4kg of undersize and 4.6kg of oversize. The oversize is further crushed and sieved (can be mixed with the next batch of materials). Take the undersize and analyze it to find that it contains 5.18% lithium. Add 890kg oxalic acid and 180kg calcium lignin sulfonate and mix for 60 minutes. After mixing, put the material into a calcining furnace at 600℃ and react for 240 minutes. After the calcined material is cooled, grind it and sieve it. Return the oversize to continue grinding until it completely passes through a 100-mesh sieve.

[0131] 4000L of pure water was added to the reactor, and the ground material was put in for primary leaching. The reaction lasted for 180 minutes, and the material was filtered to obtain 3930L of primary filtrate. 2000L of pure water was added to the reactor, and the primary leaching residue was put in. Sulfuric acid was added to control the pH value to 3.0 for secondary leaching. The reaction lasted for 120 minutes, and the secondary filtrate was 2110L and 333.7kg of secondary filter residue were obtained. The secondary filtrate can be used for the next batch of materials as the leachate for the primary leaching, and there is no loss of lithium at this time. 190kg of oxalic acid and 70kg of calcium lignin sulfonate were added to the secondary filter residue and mixed for 60 minutes. The mixture was put into a calcining furnace and reacted at 600°C for 240 minutes. After the calcined material was cooled, the powder was sieved, and the material on the sieve was returned to continue grinding until it was completely sieved through a 100-mesh sieve. The material after grinding continued the primary leaching process, and the filtrate could be used for the next batch of materials as the leachate for the primary leaching, and there was no loss of lithium at this time. At the same time, 335.8kg of filter residue was obtained, and the analysis showed that it contained 0.19% lithium. After two roastings and two leachings, the lithium yield is 95.83%.

[0132] The first leaching solution of the first roasting was 3930L, and the lithium content was 3.51g / L. Take 2000L of the first leaching solution of the first roasting, let it stand for 48 hours and then filter it. The filter surface turns yellow but there is no stacked filter residue. The filtrate is added to the reactor, and 1.5 times the theoretical amount (1.5 times is 206.8kg of liquid alkali with a mass content of 30%) of sodium hydroxide is added for causticization. After reacting at 95°C for 240 minutes, fine filtration is performed. 11.8kg of filter residue is obtained, and the lithium content is 0.56%, and the lithium yield is 99.1%. The results of the filtrate analysis are shown in Table 13 below:

[0133] Table 13: Analytical test results of filtrate (unit: mg / L)

[0134] lithium nickel cobalt manganese iron copper aluminum calcium magnesium Zinc 3477 0.53 0.47 0.99 1.53 0.33 1.35 1.21 1.01 1.16

[0135] 1000L of refined filtrate was concentrated under air isolation, crystallized at 30°C, and filtered to obtain lithium hydroxide and mother liquor. The test results of lithium hydroxide after drying are shown in Table 14 below:

[0136] Table 14: Detection results of lithium hydroxide (unit: ppm)

[0137]

[0138] The mother liquor is completely concentrated and crystallized to obtain crude lithium hydroxide for standby use. The lithium yield of lithium hydroxide production is 94.97%.

[0139] The other half of 1000L of the refined filtrate was carbonized and concentrated by passing carbon dioxide, crystallized at 30°C, and filtered to obtain lithium carbonate and mother liquor. The test results after drying the lithium carbonate are shown in Table 15 below:

[0140] Table 15: Test results of lithium carbonate (unit: ppm)

[0141]

[0142] The mother liquor is completely concentrated and crystallized to obtain crude lithium carbonate for standby use. The lithium yield of lithium hydroxide production is 94.97%.

[0143] Take 1930L of the first leaching solution from the first roasting, add sulfuric acid to adjust the pH to 1.5, and react for 120 minutes. After the reaction is completed, add lithium hydroxide, adjust the pH to 7.2, and react for 120 minutes before fine filtration. Obtain 33.2kg of filter residue, which contains 0.55% lithium and has a lithium yield of 97.30%. The filtrate is concentrated, filtered after crystallization at 30°C, and lithium sulfate and mother liquor are obtained. The drying analysis results of lithium sulfate are shown in Table 16 below:

[0144] Table 16: Analysis and test results of lithium sulfate (unit: ppm)

[0145]

[0146] All the mother liquor is returned to the static filtration process, there is no loss of lithium, and the lithium yield of lithium sulfate production is 93.24%.

Claims

1. A method for recovering lithium from waste lithium battery dismantling products and / or waste lithium battery positive electrode materials to prepare high-purity lithium hydroxide, characterized in that: The following steps are involved: (1) mixing waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials with oxalic acid, and then performing a primary roasting to obtain a primary roasting product; (2) grinding, leaching and filtering the primary roasting product obtained in step (1) to obtain a filtrate 1 and a filter residue 1; (3) adding alkali to the filtrate 1 obtained in step (2) for caustic treatment, filtering, and collecting the filtrate 2; (4) evaporating and concentrating the filtrate 2 obtained in step (3) and performing crystallization treatment, and collecting the crystals to obtain high-purity lithium hydroxide; The dismantled waste lithium battery contains lithium-containing positive electrode powder, carbon-containing negative electrode powder, fluorine-containing binder and fluorine-containing electrolyte, and the waste lithium battery positive electrode material contains lithium-containing positive electrode powder and fluorine-containing binder; calcium lignin sulfonate is also added when oxalic acid is added, and the amount of calcium lignin sulfonate added controls the mass ratio of calcium lignin sulfonate to raw materials to be (0.5-1):

1.

2. The method for preparing high-purity lithium hydroxide according to claim 1, characterized in that: The waste lithium battery dismantling materials and lithium battery positive electrode materials are first subjected to low-temperature sorting treatment. The low-temperature sorting treatment is to vibrate and screen the waste lithium battery dismantling materials and lithium battery positive electrode materials at 250-350° C. The screening particle size is controlled at 100-150 meshes, and the screened materials are collected and mixed with oxalic acid; the screened materials are collected, crushed and then screened, and the screening particle size is controlled at 100-150 meshes, and the screened materials are collected and mixed with ammonium oxalate.

3. The method for preparing high-purity lithium hydroxide according to claim 1, characterized in that: When waste lithium battery dismantling materials and / or waste lithium battery positive electrode materials are used as raw materials and mixed with oxalic acid, the mass ratio of oxalic acid to raw materials is controlled to be (2-6):1, and the mixing time is 30-90 minutes; during the first roasting, the roasting temperature is controlled to be 490-600°C, and the roasting time is 120-240 minutes.

4. The method for preparing high-purity lithium hydroxide according to claim 1, characterized in that: The alkali added during the alkali causticization treatment is at least one of sodium hydroxide, calcium hydroxide or potassium hydroxide, and the reaction temperature is controlled to be 90-95° C. and the reaction time is 120-240 min.

5. The method for preparing high-purity lithium hydroxide according to any one of claims 1 to 4, characterized in that: Sulfuric acid is added to the filter residue 1 obtained in step (2) for secondary leaching, and the filtrate 3 and filter residue 3 are obtained by filtration. The filtrate 3 is collected to the primary leaching process, and the filter residue 3 is mixed with oxalic acid for secondary roasting to obtain a secondary roasting product. The secondary roasting product is collected to the grinding process.

6. The method for preparing high-purity lithium hydroxide according to claim 5, characterized in that: When sulfuric acid is added for secondary leaching, the leaching time is 120-180 minutes, and the amount of sulfuric acid added controls the pH value of the reaction end point to be 2.5-3.

5.

7. The method for preparing high-purity lithium hydroxide according to claim 5, characterized in that: When the filter residue 3 is mixed with oxalic acid for secondary calcination, the mass ratio of oxalic acid to filter residue 3 is controlled to be (0.5-1):1, and the mixing time is 30-90 minutes; during the secondary calcination, the calcination temperature is controlled to be 490-600°C, and the calcination time is 120-240 minutes.

8. The method for preparing high-purity lithium hydroxide according to claim 7, characterized in that: When the filter residue 3 is mixed with oxalic acid, calcium lignin sulfonate is also added, and the amount of calcium lignin sulfonate added is controlled to control the mass ratio of calcium lignin sulfonate to filter residue 3 to be (0.2-0.5):

1.

9. The method for preparing high-purity lithium hydroxide according to any one of claims 1 to 4, characterized in that: The filtrate 1 obtained in step (2) is subjected to sulfation treatment, precipitation treatment, fine filtration, evaporation concentration, and crystallization treatment in sequence, and the crystals are collected to obtain high-purity lithium sulfate, wherein the sulfation treatment is to add sulfuric acid at room temperature, adjust the pH value to 0.5-1.5, and react for 60-120 minutes, and the precipitation treatment is to add lithium hydroxide at room temperature, adjust the pH value to 6.5-7.5, and react for 60-120 minutes; The filtrate 2 obtained in step (3) is subjected to carbonization treatment, and the solid phase is filtered and collected to obtain high-purity lithium carbonate. The carbonization treatment is performed by introducing carbon dioxide into the filtrate 2.

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