Method for comprehensively recovering waste ternary positive electrode powder

Abstract

The invention relates to a method for comprehensively recovering waste ternary positive electrode powder, and belongs to the technical field of waste ternary positive electrode recovery. According to the method, on the premise of lithium, carbon partial reduction is adopted, on the premise of lithium leaching, nickel, cobalt and manganese are pre-separated through wet magnetic separation, low-acid leaching, impurity removal and other processes are adopted for nickel and cobalt recovery, fine recovery of all elements can be achieved, the recovery efficiency is high, recycling of waste gas ternary positive electrode powder can be well achieved, and the method is suitable for industrial production. The method has the advantages of simple process, low cost, high recovery rate, great improvement of the recycling added value, great reduction of the addition amount of acid, alkali and hydrogen peroxide in the treatment process, environmental protection and reduction of the treatment cost, and has a high application prospect.

Description

Technical Field

[0001] The invention relates to a method for comprehensively recovering waste ternary positive electrode powder, belonging to the technical field of waste ternary positive electrode recovery. Background Art

[0002] Ternary lithium batteries are widely used in electric vehicles and energy storage due to their high energy density and long life. However, with the increase in their use, the disposal of waste ternary lithium batteries has become an urgent problem to be solved. Currently, waste ternary positive electrode powder is mainly disposed of in the following ways:

[0003] 1. Recycling

[0004] Such as hydrometallurgical leaching: by acid leaching or alkaline leaching, valuable metals such as lithium, nickel, cobalt, manganese, etc. in the ternary lithium battery are leached, and then these metals are recovered from the leachate by chemical or electrochemical methods. For example, acid leaching using a mixed solution of sulfuric acid and hydrogen peroxide can achieve a high proportion of lithium, nickel, cobalt, and manganese recovery, such as CN115954574A, a method for synergistically recovering waste lithium iron phosphate batteries and waste ternary lithium-ion battery positive electrode powder. However, this type of method requires the use of a large amount of acid and chemical reagents, which may cause secondary pollution, and at the same time has high requirements for the anti-corrosion of equipment and high processing costs. In addition, the leaching efficiency is affected by process conditions such as temperature, time, acid concentration, etc., and the operation is relatively complicated.

[0005] Another example is pyrometallurgy: through high-temperature smelting, the metal elements in the ternary positive electrode powder are converted into alloy or metal form, and then separated and purified. This method is suitable for treating large-scale battery waste, but it has high energy consumption and may produce harmful gases. For example, Wang Wenlong, et al. Research Progress on Resource Regeneration of Waste Ternary Lithium Battery Positive Electrode Materials, Journal of Engineering Science, 2023, 45(9): 1470-1481. However, this type of method has high process energy consumption, and harmful gases may be produced during high-temperature smelting, requiring additional gas treatment facilities. In addition, this process may cause resource loss and reduce the recovery rate of metals.

[0006] 2. Modification and reuse

[0007] For example, ion doping: by doping other ions, such as magnesium and aluminum, into the ternary cathode material, its structural stability and cycle performance can be improved, thereby extending the battery life. However, the ion doping technology in modified reuse may change the structural stability of the original material, but it may also affect its electrochemical properties. In addition, the doping process increases the production steps and costs, and requires precise control of the doping amount and conditions, otherwise it may lead to unstable performance.

[0008] Another example is surface coating: coating the surface of the ternary cathode material with a layer of protective material, such as carbon, oxide, etc., can reduce the direct contact between the electrode material and the electrolyte, and improve the cycle stability and safety of the battery. However, although surface coating can improve the cycle stability of the battery, it may also reduce the energy density of the battery. The uniformity and bonding strength of the coating material have an important impact on the final performance, which is difficult to ensure consistency in large-scale production.

[0009] 3. Direct regeneration

[0010] For example, electrode material regeneration: waste ternary positive electrode powder is directly used in the production of new batteries after appropriate physical and chemical treatment. For example, the direct recycling of waste materials can be achieved by recovering ternary positive electrode materials through a one-step method combining acid leaching-coprecipitation-high temperature solid state. For example, patent application CN1 11206148A is a method for preparing ternary positive electrode materials by recycling waste ternary lithium batteries, but the method does not make a diversion when treating nickel, cobalt and manganese, and all nickel, cobalt and manganese enter the leaching solution. The extraction process adopts a full extraction process, and the product is a single metal salt. The pre-extraction liquid contains nickel sulfate / cobalt sulfate / manganese sulfate / sodium sulfate, which are all impurities. The element recovery effect is poor and it is not convenient for subsequent use; and the method consumes a lot of acid and alkali, which is not conducive to environmental protection. Another example is patent application CN112646974A, a method for recovering valuable metals from waste ternary lithium battery positive electrode materials, but this article also has the above-mentioned shortcomings of large acid and alkali consumption and poor recovery effect of each element. Summary of the invention

[0011] In view of the above-mentioned deficiencies in the prior art, the object of the present invention is to provide a method for comprehensively recovering waste ternary positive electrode powder.

[0012] In a first aspect, the present invention provides a method for comprehensively recovering waste ternary positive electrode powder, comprising the following steps:

[0013] Step 1, lithium preparation: the ternary positive electrode powder is subjected to reduction roasting, water leaching for lithium extraction and solid-liquid separation in sequence to obtain filter residue A and lithium-rich filtrate 1 respectively, and the lithium-rich filtrate 1 is enriched, concentrated and crystallized to obtain lithium carbonate crystals;

[0014] Step 2, wet magnetic separation: the filter residue A obtained in step 1 is slurried, and then the slurried material is subjected to magnetic separation to obtain magnetic solids, weakly magnetic solids and washing water;

[0015] Step 3, magnetic solid treatment: disperse the magnetic solid in deionized water, adjust the system pH, heat, then add hydrogen peroxide and stir to react, filter to obtain filtrate 2 and residue B; then remove Fe 3+ 、Al 3+ and remove some Ca2+ and Mg 2+ , and then extract and separate to obtain nickel sulfate / cobalt solution and copper manganese water;

[0016] Step 4, weak magnetic solid treatment: disperse the weak magnetic solid, filter residue B and copper-manganese water in deionized water, add concentrated sulfuric acid to adjust the pH of the solution, add hydrogen peroxide, heat and stir to react, and filter to obtain a copper-removing filtrate 3 and a filter residue C; remove copper, iron and aluminum, calcium and magnesium from the filtrate 3, extract and separate, and remove oil to obtain a manganese sulfate solution and a stripping solution.

[0017] Further, the reduction roasting in step 1 includes:

[0018] Add carbon powder to the ternary positive electrode powder and mix well, then calcine it at 600-800°C in an inert atmosphere, and cool it after calcination.

[0019] Furthermore, the mass ratio of the added ternary positive electrode powder and the reduced carbon powder is 1:(0.04-0.12);

[0020] Furthermore, the roasting time is 60-240min:

[0021] The inert atmosphere is at least one of a nitrogen atmosphere and an argon atmosphere;

[0022] The reaction equation of the reduction roasting process is as follows:

[0023] 4LiNi 0.6 Co 0.2 Mn 0.2 O2+C→Li2CO3+Li2O+2.4NiO+0.8CoO+0.8MnO

[0024] 4LiNi 0.6 Co 0.2 Mn 0.2 O2+2.6C→2Li2CO3+CO2+2.4Ni+0.8Co+0.8MnO

[0025] After the reduction roasting process, most of the lithium nickel cobalt manganese oxide in the ternary positive electrode powder is reduced to lithium oxide, lithium carbonate, nickel oxide, cobalt oxide, and manganese oxide; a small part is reduced to lithium carbonate, metallic nickel, metallic cobalt, and manganese oxide.

[0026] Furthermore, the water leaching and lithium extraction in step 1 includes:

[0027] Water is added to the ternary powder obtained after reduction roasting to make a slurry, ball milling is performed, reaction is carried out at 50-80° C. under stirring, and then filtering is performed.

[0028] Furthermore, the solid-liquid mass ratio after the water-adding slurry is 1:(8-20);

[0029] Furthermore, the stirring rate is 50-300 r / min, and the reaction time is 60-240 min;

[0030] The reaction equation for this step is as follows: 2LiOH+H2O→2LiOH

[0031] Li2CO3 and Li2O in the ternary positive electrode powder obtained after reduction roasting are easily soluble in water, while the mixture of nickel oxide, cobalt oxide and manganese oxide is difficult to dissolve in water. Lithium is extracted by water leaching. The filtrate 1 contains a mixture of lithium carbonate and lithium hydroxide, and the filter residue A is nickel, cobalt and manganese oxides and carbon powder, and also contains a small amount of lithium carbonate, lithium oxide, metallic nickel and metallic cobalt.

[0032] Furthermore, the enrichment, concentration and crystallization in step 1 comprises:

[0033] In an air atmosphere, the pH of the filtrate 1 is adjusted to 8-10, and an osmotic treatment is performed under pressure to obtain a clear solution and a concentrated solution. The concentrated solution is evaporated, concentrated and thermally crystallized to obtain lithium carbonate crystals.

[0034] Furthermore, the pressure condition is 0.8-2MPa;

[0035] Furthermore, the lithium content in the concentrate is required to be 2-6 g / L;

[0036] The reaction equation of this step is as follows: LiOH+CO2→Li2CO3;

[0037] Further, the slurrying in step 2 includes:

[0038] Deionized water and / or the clear liquid and / or the washing water are added to the filter residue A.

[0039] Furthermore, the magnetic separation in step 2 includes:

[0040] Using magnetic separation equipment to magnetically separate the slurry to obtain magnetic solids and mixed materials, and filtering the mixed materials to obtain weakly magnetic solids and washing water;

[0041] Furthermore, during magnetic separation, the magnetic field strength is 800-8000GS;

[0042] Furthermore, the magnetic separation device is a magnetic separator;

[0043] Metallic nickel and metallic cobalt, such as nickel oxide and cobalt oxide, have strong magnetism and are intercepted and collected by magnetic separation equipment under the action of the magnetic field. Therefore, the main components of magnetic solids are nickel oxide and cobalt oxide, and they also contain a small amount of metallic nickel, metallic cobalt, manganese oxide, copper oxide, iron, calcium, magnesium, aluminum and other ions;

[0044] Manganese oxide and carbon powder have weak magnetism. The mixture passes through magnetic separation equipment and is filtered to obtain weak magnetic solid and washing water. Therefore, the main components of the weak magnetic solid are manganese oxide and carbon powder, and also contain a small amount of metal nickel, metal cobalt, manganese oxide, nickel oxide, copper oxide, iron, calcium, magnesium, aluminum and other ions;

[0045] Further, the pH in step 3 is 1.5-3.0;

[0046] Further, after adding deionized water, the solid-liquid mass ratio was 1:4;

[0047] Further, the heating temperature is 60-80°C;

[0048] Further, the reaction time of adding hydrogen peroxide is 120-240min;

[0049] Further, the stirring rate is 50-300r / min;

[0050] The reaction equation for obtaining the residue B and filtrate 2 is as follows:

[0051] NiO+H2SO4→NiSO4+H2O

[0052] CoO+H2SO4→CoSO4+H2O

[0053] MnO+H2SO4→MnSO4+H2O

[0054] CuO+H2SO4→CuSO4+H2O

[0055] 2Fe 2+ +2H + +H2O2→2Fe 3+ +2H2O

[0056] Ni+H2O2+H2SO4→NiSO4+H2O

[0057] Co+H2O2+H2SO4→CoSO4+H2O

[0058] The main components of filtrate 2 are nickel sulfate / cobalt, and it also contains a small amount of manganese ions, copper ions, iron ions, aluminum ions and trace amounts of calcium and magnesium ions;

[0059] The main components of the filter residue B are a small amount of undissolved metallic nickel, metallic cobalt and a small amount of carbon powder.

[0060] Further, the Fe in the filtrate 2 is removed in step 3. 3+ 、Al 3+ and removal of some Ca 2+ Mg 2+ The process includes:

[0061] Heat the filtrate 2 to 60-85°C, add Ni(OH)2 to adjust the filtrate 2

[0062] pH to 4-6, Fe in filtrate 2 3+ 、Al 3+ Precipitation is then performed, followed by solid-liquid separation, and the resulting liquid is filtered through a chelating resin column to remove some of the Ca 2+ Mg 2+ ,get.

[0063] In this process, the reaction equation is as follows:

[0064] 3Ni(OH)2+Fe2(SO4)3→3NiSO4+2Fe(OH)3

[0065] 3Ni(OH)2+Al2(SO4)3→3NiSO4+2Al(OH)3

[0066] 2R-H+Ca 2+ →2R-Ca+2H +

[0067] 2R-H+Mg 2+ →2R-Mg+2H +

[0068] In the nickel sulfate / cobalt precursor solution, Ca is required to be less than 0.002-0.02 g / L, Mg is required to be less than 0.002-0.02 g / L, Fe is required to be less than 0.002-0.02 g / L, and Al is required to be less than 0.002-0.02 g / L.

[0069] Further, the extraction separation in step 3 includes:

[0070] The Fe in filtrate 2 will be removed 3+ 、Al 3+ and removal of some Ca 2+ Mg 2+ The nickel sulfate / cobalt pre-extraction solution obtained is added to the extraction solution, and then the Ni, Co, Mn and Na in the manganese sulfate pre-extraction solution are separated through saponification, extraction, nickel-cobalt removal, manganese removal and regeneration processes, and then the nickel sulfate / cobalt solution and copper-manganese water are obtained through oil removal.

[0071] Furthermore, the extract is prepared by P204 extractant and diluent in a mass ratio of 1: (3-6); the extract can extract and separate metals, so that Cu and Mn in the nickel sulfate / cobalt pre-extraction solution are separated from the main component nickel sulfate / cobalt solution.

[0072] In the obtained nickel sulfate / cobalt solution, Cu is less than 0.001-0.005 g / L, Mn is less than 0.01-0.1 g / L, Na is less than 0.1-1 g / L, Ca is less than 0.002-0.02 g / L, Mg is less than 0.002-0.02 g / L, Fe is less than 0.002-0.01 g / L, and Al is less than 0.002-0.01 g / L.

[0073] The reaction equation is as follows:

[0074] P204-H+NaOH→P204-Na+H2O

[0075] 2P204-Na+NiSO4→2P204-Ni+Na2SO4

[0076] 2P204-Ni+CuSO4→2P204-Cu+NiSO4

[0077] 2P204-Ni+MnSO4→2P204-Mn+NiSO4

[0078] 2P204-Cu+H2SO4→2P204-H+CuSO4

[0079] 2P204-Mn+H2SO4→2P204-H+MnSO4

[0080] Further, the pH in step 4 is 0.5-1.5;

[0081] Further, the heating temperature is 60-80°C;

[0082] Furthermore, the reaction time of adding hydrogen peroxide is 120-240 min, and the stirring rate is 50-300 r / min;

[0083] The reaction equation of this process is as follows:

[0084] MnO+H2SO4→MnSO4+H2O

[0085] NiO+H2SO4→NiSO4+H2O

[0086] CoO+H2SO4→CoSO4+H2O

[0087] CuO+H2SO4→CuSO4+H2O

[0088] 2Fe 2+ +2H + +H2O2→2Fe 3+ +2H2O

[0089] Ni+H2O2+H2SO4→NiSO4+H2O

[0090] Co+H2O2+H2SO4→CoSO4+H2O

[0091] The main component of filtrate 3 is manganese sulfate, and it also contains a small amount of nickel, cobalt, copper ions, iron, aluminum ions, and trace amounts of calcium and magnesium ions;

[0092] The main component of the filter residue C is carbon powder.

[0093] Further, the copper removal process of the filtrate 3 in step 4 includes:

[0094] The filtrate is heated to 50-70°C, iron powder is added in a molar ratio of 1:1 and reacted for 60-180 minutes to remove the copper element by solid-liquid separation;

[0095] The reaction equation of this process is as follows: CuSO4+Fe→FeSO4+Cu.

[0096] Further, the iron and aluminum removal process of the filtrate 3 in step 4 includes:

[0097] Hydrogen peroxide is added to the liquid obtained after copper removal at a molar ratio of hydrogen peroxide to iron element of (2-6):1, the temperature is raised to 60-85°C, NaOH is added to adjust the solution pH to 4-5 to obtain iron and aluminum precipitation, and solid-liquid separation is performed.

[0098] The reaction equation of this process is as follows:

[0099] 6NaOH+Fe2(SO4)3→3Na2SO4+2Fe(OH)3

[0100] 6NaOH+Al2(SO4)3→3Na2SO4+2Al(OH)3

[0101] Further, the calcium and magnesium removal process of the filtrate 3 in step 4 includes:

[0102] The filtrate obtained after removing iron and aluminum is heated to 70-95°C, NaOH is added to adjust the solution pH to 5-6, sodium fluoride is added according to the molar ratio of sodium fluoride to calcium and magnesium elements (200-600):1 to generate Ca and Mg precipitation, and solid-liquid separation is performed. The obtained filtrate is the manganese sulfate pre-extraction solution.

[0103] Before manganese sulfate extraction, the following conditions are met: Ca<0.002-0.02g / L, Mq<0.002-0.02g / L, Fe<0.002-0.02g / L, Al<0.002-0.02g / L.

[0104] The reaction equation of this process is as follows:

[0105] 2NaF+CaSO4→CaF2+Na2SO4

[0106] 2NaF+MgSO4→MgF2+Na2SO4.

[0107] Further, the extraction and separation process in step 4 is:

[0108] The manganese sulfate pre-extraction solution is added to the extractant, and Ni, Co, Mn and Na in the manganese sulfate pre-extraction solution are separated through saponification, extraction, nickel-cobalt removal, manganese removal and regeneration, and the manganese sulfate solution and stripping solution are obtained through oil removal;

[0109] The extractant is prepared by mixing P204 extractant and diluent (260# solvent oil) in a volume ratio of 1:(3-6);

[0110] In the manganese sulfate solution, Cu is required to be less than 0.001-0.005 g / L, Ni is less than 0.01-0.1 g / L, Co is less than 0.01-0.1 g / L, Na is less than 0.1-1 g / L, Ca is less than 0.002-0.02 g / L, Mg is less than 0.002-0.02 g / L, Fe is less than 0.002-0.01 g / L, and Al is less than 0.002-0.01 g / L.

[0111] The reaction equation of this process is as follows:

[0112] P204-H+NaOH→P204-Na+H2O

[0113] 2P204-Na+MnSO4→2P204-Mn+Na2SO4

[0114] 2P204-Na+CoSO4→2P204-Co+Na2SO4

[0115] 2P204-Na+NiSO4→2P204-Ni+Na2SO4

[0116] 2P204-Ni+H2SO4→2P204-H+NiSO4

[0117] 2P204-Co+H2SO4→2P204-H+CoSO4

[0118] 2P204-Mn+H2SO4→2P204-H+MnSO4.

[0119] In a second aspect, a nickel sulfate / cobalt solution is provided, which is prepared using the method described in the first scheme.

[0120] In a third aspect, a manganese sulfate solution is provided, which is prepared using the method described above.

[0121] In a fourth aspect, a ternary cathode material precursor is provided, which is prepared from the above-mentioned nickel sulfate / cobalt solution.

[0122] In a fifth aspect, a ternary positive electrode material precursor is provided, which is prepared from the manganese sulfate solution obtained above.

[0123] In a sixth aspect, a ternary positive electrode material precursor is provided, which is prepared from the nickel sulfate / cobalt solution and manganese sulfate solution obtained above in a certain proportion.

[0124] Compared with the prior art, the method for comprehensive recovery of waste ternary positive electrode powder provided by the present application has the following effects:

[0125] 1. The initial lithium is partially reduced by carbon, and the product is mainly metal oxides. The amount of carbon powder added is small, and the initial lithium yield is high, which can effectively reduce the acid consumption of subsequent nickel, cobalt and manganese leaching, reduce the generation of acid waste liquid, reduce the subsequent acid waste liquid treatment process and reduce costs;

[0126] 2. The lithium leaching solution is used, and the lithium content concentration is low. After reverse osmosis concentration and recrystallization, the obtained lithium carbonate has high purity, which greatly reduces the cost of evaporation and concentration;

[0127] 3. Pre-separation of nickel, cobalt and manganese by wet magnetic separation. The magnetism is used to pre-separate nickel, cobalt and manganese in advance. The initial separation effect is good, and the separation effect of nickel, cobalt and manganese reaches 90-95%, which shortens the metal separation process. Compared with the traditional battery recycling, at least 5 extractions are required for separation. In this patent, nickel, cobalt and manganese are pre-separated by wet magnetic separation, and only 2 extractions are required, which greatly shortens the process.

[0128] 4. Nickel and cobalt recovery adopts low acid leaching and impurity removal process, nickel and cobalt are not separated, and acid and alkali consumption is further reduced; manganese recovery adopts high acid leaching and full extraction separation, nickel and cobalt yield is high, which is convenient for better utilization; the comprehensive extraction pressure is small, the production cost is low, and the nickel and cobalt yield is high;

[0129] 5. The product solution is prepared by nickel sulfate / cobalt solution and manganese sulfate solution. The mixed solution is used as the product, which has low requirements for the extraction line. The nickel sulfate / cobalt solution has low requirements for manganese ions; the manganese sulfate solution has low requirements for nickel and cobalt ions, and the extraction line has low requirements. The preparation process is simple and easy to operate, and the preparation efficiency is high.

[0130] 6. The method provided by the present invention can realize the fine recovery of various elements with high recovery efficiency, can better realize the resource utilization of waste gas ternary positive electrode powder, and can greatly improve the added value of its recycling and utilization, and has a high application prospect. BRIEF DESCRIPTION OF THE DRAWINGS

[0131] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0132] in:

[0133] Figure 1 The present invention is a flow chart of comprehensive recovery of waste ternary positive electrode powder in one embodiment. DETAILED DESCRIPTION

[0134] In order to enable those skilled in the art to better understand the technical solutions in the present application, the technical solutions in the embodiments of the present application will be clearly and completely described below in conjunction with the drawings in the embodiments of the present application. Obviously, the described embodiments are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments in the present application, all other embodiments obtained by ordinary technicians in the field without creative work are within the scope of protection of this application.

[0135] Examples 1 to 4 and Comparative Examples 1 to 3

[0136] like Figure 1 As shown, Example 1 provides a method for comprehensively recovering waste ternary positive electrode powder, comprising:

[0137] Step 1: Prerequisite lithium

[0138] Step 1.1, reduction roasting:

[0139] The ternary positive electrode powder is added to the reduced carbon powder, mixed evenly, and roasted in an atmosphere reduction furnace with a preset roasting temperature and roasting time. Under a nitrogen atmosphere, the material is heated to a temperature of 700°C. After reaching the preset reaction temperature, the reaction time is set to 140 minutes. After the roasting is completed, the crucible is fully cooled and the material in the crucible is taken out;

[0140] Step 1.2 Water leaching for lithium extraction:

[0141] The ternary positive electrode powder after reduction roasting is added to the slurry (solid-liquid mass ratio is 1:15), and added to the ball mill for wet ball milling. After ball milling, the slurry is transferred into the reactor for stirring. The reaction time is 60-240min, the reaction temperature is 50-80°C, and the stirring rate is 200r / min. After the reaction is completed, it is filtered through a filter press to obtain filtrate 1 and filter residue A;

[0142] Step 1.3 Lithium solution enrichment and concentration:

[0143] The filtrate 1 in step 1.2 is transferred into a reactor, a blower is turned on to blow in a large amount of air, the pH of the solution is adjusted, and the solution is transferred to a high-pressure reverse osmosis device and pressurized to obtain a clear solution and a concentrated solution. The clear solution is used as the slurry solution in step 1.2 and step 2. The concentrated solution is evaporated and concentrated, and thermally crystallized to obtain lithium carbonate crystals;

[0144] Step 2: Wet magnetic separation

[0145] Add the filter residue A in step 1.2 into the reactor, add slurry liquid to a solid-liquid mass ratio of 1:12, pump the slurry liquid into a wet magnetic separator to obtain magnetic solids and a mixture, pass the mixture through a magnetic separator, and then filter it through a filter press to obtain weak magnetic solids and washing water, and use the washing water as the slurry liquid in step 1.2;

[0146] Step 3: Magnetic solid processing

[0147] Step 3.1 Dissolution of magnetic solid:

[0148] Add the magnetic solid in step 1.2 into a reactor, add deionized water to a solid-liquid mass ratio of 1:4, add concentrated sulfuric acid to adjust the pH of the solution, add hydrogen peroxide at 70°C, according to the mass ratio of hydrogen peroxide to magnetic solid of 4:100, react for 180 minutes, stir at a rate of 200 r / min, filter through a filter press to obtain filtrate 2 and filter residue B;

[0149] Step 3.2: Nickel sulfate / cobalt solution impurity removal:

[0150] The filtrate 2 of step 3.1 is heated to 75°C, Ni(OH)2 is added to adjust the solution pH, Fe3+ and Al3+ in the filtrate are precipitated, solid-liquid separation is performed by a filter press, and the filtrate is passed through a chelating resin column B-L016 at a speed of 12BV to further reduce the content of Ca and Mg in the filtrate to obtain a nickel sulfate / cobalt pre-extraction solution;

[0151] 3.3 Nickel sulfate / cobalt extraction and impurity removal:

[0152] The nickel sulfate / cobalt pre-extraction solution of step 3.2 is transported to a P204 extraction tank for extraction, and the P204 extractant is mixed with a diluent (260# solvent oil) in a volume ratio of 1:4, and then subjected to saponification, soap transfer, extraction, stripping, and regeneration to separate the impurities Cu and Mn in the nickel sulfate / cobalt pre-extraction solution from the main component nickel sulfate / cobalt solution, and degrease with a degreaser to obtain a nickel sulfate / cobalt solution and copper-manganese water;

[0153] Step 4: Weakly Magnetic Solid Processing

[0154] Step 4.1 Dissolution of weakly magnetic solid:

[0155] The weakly magnetic solid in step 2, the filter residue in step 3.1 and the copper-manganese water in step 3.3 are added to a reactor, deionized water is added to a solid-liquid mass ratio of 1:4, concentrated sulfuric acid is added to adjust the pH of the solution, hydrogen peroxide is added at 70°C, the reaction is carried out for 180 minutes, the stirring rate is 200r / min, and the solution is filtered through a filter press to obtain filtrate 3 and filter residue C.

[0156] Step 4.2, impurity removal of manganese sulfate leaching solution:

[0157] Step 4.2.1 Copper removal: add the filtrate of step 4.1 into the reactor, heat the reaction to 60°C, add reduced iron powder according to the measured amount, react for 120 minutes, separate the solid and liquid by a filter press, and obtain the copper removal filtrate;

[0158] Step 4.2.2: Iron and aluminum removal: hydrogen peroxide is added to the copper removal filtrate at a ratio of m(hydrogen peroxide): m(iron element) = 2-6:1, the reaction temperature is raised to 70°C, NaOH is added to adjust the solution pH, Fe3+ and Al3+ in the filtrate are precipitated, and solid-liquid separation is performed by a filter press to obtain an iron and aluminum removal filtrate;

[0159] Step 4.2.3 Calcium and magnesium removal: Heat the filtrate again after removing iron and aluminum, add NaOH to adjust the solution, add sodium fluoride, and remove the Ca 2+ Mg 2+ Precipitation is performed, and solid-liquid separation is performed by a filter press to obtain a manganese sulfate pre-extraction liquid;

[0160] Step 4.3: Extraction and separation of manganese sulfate P204

[0161] The manganese sulfate pre-extraction solution in step 4.2.3 is transported to the P204 extraction tank for extraction. The P204 extractant and the diluent (260# solvent oil) are mixed in a volume ratio of 1:4.5, and then Ni, Co, Mn and Na in the manganese sulfate pre-extraction solution are separated by saponification, extraction, nickel-cobalt removal, manganese removal and regeneration. The oil is removed by the deoiler to obtain the manganese sulfate solution and the nickel / cobalt sulfate stripping solution, which can be returned to step 3.1 for leaching.

[0162] The parameter settings in Examples 1 to 4 and Comparative Examples 1 to 3 are shown in Table 1.

[0163] Table 1

[0164]

[0165] Comparative Example 4

[0166] This comparative example adopts the existing ternary positive electrode powder recovery method, specifically referring to Example 1 of CN112646974A:

[0167] (1) Calcination reduction: Take 100 parts of disassembled and crushed ternary lithium battery positive electrode materials, mix them evenly with 20 parts of carbon powder, place them in a reduction furnace, heat to 600°C, and keep warm for 1.5 hours;

[0168] (2) Water immersion: pour the calcined material after being fully calcined and reduced in step (1) into 100 parts of reducing agent solution while hot and soak for 0.5 h;

[0169] (3) Selective lithium extraction: 5% dilute H2SO4 was added dropwise to the mixed liquid after water immersion in step (2) to adjust the pH of the solution to 2.0, react for 2.5 hours, then adjust the pH to 8.5, react for 1 hour to precipitate the alkali, and filter to achieve solid-liquid separation of lithium liquid and metal slag such as nickel, cobalt, and manganese;

[0170] (4) Acid leaching: add 300 parts of pure water to the filter cake obtained by filtering in step (3), slurry it, pump it into a stirred reactor, heat it to 60° C., add concentrated sulfuric acid dropwise, keep the pH of the roasting material mixed solution in the stirred reactor at 0.5, and at the same time, add 5 g / L hydrogen peroxide solution dropwise, soak it for 1 hour, filter it, and wash it;

[0171] (5) Purification of nickel-cobalt-manganese solution: adjusting the pH of the mixed filtrate obtained in (4) to 2.0, filtering, and resolving to obtain Fe2O3, Al2O3 and a second filtrate; adding 1.0 times the theoretical amount of fluoride salt to the second filtrate, stirring at a temperature of 50°C for 1.0h, filtering, and obtaining CaF2, MgF2, LiF filter cakes and a nickel-cobalt-manganese salt mixed solution; subjecting the nickel-cobalt-manganese leaching solution to the steps of removing iron, aluminum, calcium, magnesium, and lithium to obtain a decontaminated solution, and then organically extracting cobalt, manganese, and nickel from the decontaminated solution.

[0172] Comparative Example 5

[0173] This comparative example adopts the existing ternary positive electrode powder recovery method, specifically referring to CN1 11206148A Example 1:

[0174] (1) The waste lithium batteries were placed in a 1.5 mol / L NaCl solution for discharge treatment. The discharged waste lithium batteries were cleaned and dried, and then coarsely and finely crushed. They were placed in a rotary kiln for pyrolysis at 300°C under nitrogen protection, and then 100 kg of waste ternary positive electrode powder (Li: 11.76, Ni: 25.63, Co: 8.91, Mn: 13.38 wt%) was obtained by sorting.

[0175] (2) The waste ternary positive electrode powder obtained by pretreatment is mixed with 1.2 times the theoretical amount of ammonium sulfate, sent to a high-temperature furnace, and roasted at 500°C for 2h.

[0176] (3) The calcined waste positive electrode powder is leached in pure water at a liquid-solid ratio of 5:1, the immersion time is 3 hours, and the immersion temperature is 65° C. The slurry after immersion is filtered to obtain a lithium-containing leaching solution, and lithium is recovered by removing impurities, concentrating, and adding sodium carbonate.

[0177] (4) After water leaching, 205 g / L sulfuric acid and 7 g / L hydrogen peroxide were added to the leached residue at a liquid-to-solid ratio of 5:1 for acid leaching. The terminal pH value was about 2. The mixture was stirred at 50°C for 5 h. The metal or metal oxide was converted into metal sulfate. After filter pressing, a metal sulfate solution was obtained.

[0178] (5) The pH value of the filtrate after acid leaching is controlled at 1.5 to remove the copper impurity. Then, 1.2 times the theoretical amount of hydrogen peroxide is added to the copper-removed feed solution, stirred at 90-95°C for 0.5h, and a measured amount of sodium hydroxide solution is added, and the pH value is adjusted to 4.5 to precipitate and separate the iron and aluminum ions in the feed solution.

[0179] (6) P204 (20%)-sulfonated kerosene (80%) system was used to extract impurities in the impurity-removed liquid, so that impurities such as calcium, magnesium, copper, zinc and part of manganese in the solution were extracted into the P204 organic phase. Then, P507 (20%)-sulfonated kerosene (80%) system was used to extract cobalt and manganese in the impurity-removed liquid, and cobalt and manganese entered the organic phase, and nickel remained in the aqueous phase. P204 (20%)-sulfonated kerosene (80%) system was used to extract nickel in the impurity-removed cobalt and manganese residual liquid. The organic phase was saponified with 5 mol / L sodium hydroxide solution, and the saponification rate of the organic liquid was 50%. Sulfuric acid with a concentration of 1 mol / L was used for stripping to obtain pure cobalt sulfate, manganese sulfate and nickel sulfate solutions. After detection and analysis, the masses of cobalt sulfate, manganese sulfate and nickel sulfate were 22.95 kg, 36.02 kg and 65.53 kg respectively.

[0180] (7) The ratio of nickel, cobalt and manganese in nickel sulfate, cobalt sulfate and manganese sulfate solutions is adjusted to 5:2:3, and a 5 mol / L sodium hydroxide solution and 8 mol / L ammonia water are added for coprecipitation reaction. After the reaction is completed, a precursor is obtained by filtration, washing and drying. The precursor is mixed with a measured amount of lithium carbonate and sintered at 930°C. After iron is screened out, a ternary positive electrode material is obtained. The highest recovery rates of nickel, cobalt and manganese are 98%, 99% and 98%, respectively. Tests have found that this method uses an extractant to separate one by one. During the extraction process, 1 to 1.5 times the theoretical liquid alkali and 1 to 1.5 times the theoretical sulfuric acid are consumed in the nickel separation process. The acid and alkali consumption in the cobalt and manganese separation process is also large. The total acid consumption coefficient is 2.5 to 3, and the total alkali consumption coefficient is 1.5 to 2.0. A large amount of raffinate (sodium sulfate wastewater) will also be generated for treatment.

[0181] The recovery effect of each element in Examples 1 to 4 and Comparative Examples 1 to 3 was tested, and the test results are shown in Table 2:

[0182] Table 2

[0183]

[0184] Among them, the acid consumption coefficient described in the table is the multiple of sulfuric acid required for the nickel cobalt manganese sulfate solution; the alkali consumption coefficient is the multiple of liquid alkali required for complete precipitation of the nickel cobalt manganese sulfate solution; and the hydrogen peroxide consumption coefficient is the multiple of hydrogen peroxide required for complete reaction of nickel cobalt and hydrogen peroxide.

[0185] It can be seen from Table 2 that the recovery of ternary positive electrode powder by the test method of the present application has a high recovery efficiency, and does not require a large amount of acid to be added for acid leaching, which can reduce the amount of acid used; since each process cooperates with each other, the recovery effect of each element is good, and the amount of alkali and hydrogen peroxide used in the treatment process is greatly reduced; and when the magnetic separation conditions, such as the magnetic separation intensity, are changed, the magnetic separation effect of the metal elements becomes worse, and the acid and alkali consumption may increase; the amount of carbon powder added affects the amount of hydrogen peroxide used and the yield of lithium, because the amount of carbon powder added plays a leading role in the reduction of lithium, and excessive carbon powder will cause over-reduction, resulting in the production of metallic nickel and cobalt, and the consumption of hydrogen peroxide increases; the pH of the dissolution of weak magnetic solids affects the nickel, cobalt and manganese yields. When the pH is low and the acidity is strong, the nickel, cobalt and manganese yields are relatively high.

[0186] The technical features of the above embodiments may be combined arbitrarily. To make the description concise, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0187] The above-mentioned embodiments only express several implementation methods of the present application, and the descriptions thereof are relatively specific and detailed, but they cannot be understood as limiting the scope of the present application. It should be pointed out that, for a person of ordinary skill in the art, several variations and improvements can be made without departing from the concept of the present application, and these all belong to the protection scope of the present application. Therefore, the protection scope of the present application shall be subject to the attached claims.

Claims

1. A method for comprehensive recovery of waste ternary positive electrode powder, characterized in that: The steps include: Step 1, lithium preparation: performing reduction roasting, water leaching and lithium extraction, and solid-liquid separation on the ternary positive electrode powder in sequence to obtain filter residue A and lithium-rich filtrate 1, respectively, and enriching, concentrating and crystallizing the lithium-rich filtrate 1 to obtain lithium carbonate crystals; Step 2, wet magnetic separation: the filter residue A obtained in step 1 is slurried, and then the slurried material is subjected to magnetic separation to obtain magnetic solids, weakly magnetic solids and washing water; Step 3, magnetic solid treatment: disperse the magnetic solid in deionized water, adjust the system pH, heat, then add hydrogen peroxide and stir to react, filter to obtain filtrate 2 and residue B; then remove Fe 3+ 、Al 3+ and remove some Ca2+ and Mg 2+ , and then extract and separate to obtain nickel sulfate / cobalt solution and copper manganese water; Step 4, weak magnetic solid treatment: disperse the weak magnetic solid, filter residue B and copper-manganese water in deionized water, add concentrated sulfuric acid to adjust the pH of the solution, add hydrogen peroxide, heat and stir to react, and filter to obtain a copper-removing filtrate 3 and a filter residue C; remove copper, iron and aluminum, calcium and magnesium from the filtrate 3, extract and separate, and remove oil to obtain a manganese sulfate solution and a stripping solution.

2. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: The enrichment, concentration and crystallization in step 1 comprises: In an air atmosphere, the pH of the filtrate 1 is adjusted to 8-10, and an osmotic treatment is performed under pressure to obtain a clear solution and a concentrated solution. The concentrated solution is evaporated, concentrated and thermally crystallized to obtain lithium carbonate crystals.

3. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: The magnetic separation in step 2 comprises: The slurry is magnetically separated by magnetic separation equipment to obtain magnetic solids and mixed materials, and the mixed materials are filtered to obtain weakly magnetic solids and washing water.

4. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: Removal of Fe in filtrate 2 as described in step 3 3+ 、Al 3+ and removal of some Ca 2+ Mg 2+ The process includes: Heat the filtrate 2 to 60-85°C, add Ni(OH)2 to adjust the filtrate 2 pH to 4-6, Fe in filtrate 2 3+ 、Al 3+ Precipitation is then performed, followed by solid-liquid separation, and the resulting liquid is filtered through a chelating resin column to remove some of the Ca 2+ Mg 2+ ,get.

5. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: The extractive separation described in step 3 comprises: The Fe in filtrate 2 will be removed 3+ 、Al 3+ and removal of some Ca 2+ Mg 2+ The nickel sulfate / cobalt pre-extraction solution obtained is added to the extraction solution, and then the Ni, Co, Mn and Na in the manganese sulfate pre-extraction solution are separated through saponification, extraction, nickel-cobalt removal, manganese removal and regeneration processes, and then the nickel sulfate / cobalt solution and copper-manganese water are obtained through oil removal.

6. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: The copper removal process of the filtrate 3 in step 4 includes: The filtrate is heated to 50-70°C, iron powder is added in a molar ratio of 1:1 and reacted for 60-180 minutes to remove the copper element by solid-liquid separation; The iron and aluminum removal process of the filtrate 3 in step 4 includes: According to the molar ratio of hydrogen peroxide to iron element of (2-6):1, hydrogen peroxide is added to the liquid obtained after copper removal, the temperature is raised to 60-85°C, NaOH is added to adjust the solution pH to 4-5 to obtain iron and aluminum precipitation, and solid-liquid separation is performed; The calcium and magnesium removal process of the filtrate 3 in step 4 includes: The filtrate obtained after removing iron and aluminum is heated to 70-95°C, and NaOH is added to adjust the solution pH to 5-6. Sodium fluoride is added according to the molar ratio of sodium fluoride to calcium and magnesium elements (200-600):1 to generate Ca and Mg precipitation, and solid-liquid separation is performed. The filtrate obtained is the pre-extraction solution of manganese sulfate; sodium fluoride is added to generate insoluble calcium fluoride and magnesium fluoride, open the circuit of calcium and magnesium in the system, maintain the system balance, and make the product meet the standards.

7. The method for comprehensive recovery of waste ternary positive electrode powder according to claim 1, characterized in that: The process of extraction and separation described in step 4 is: The manganese sulfate pre-extraction solution is added to the extractant, and Ni, Co, Mn and Na in the manganese sulfate pre-extraction solution are separated through saponification, extraction, nickel-cobalt removal, manganese-removal and regeneration, and the manganese sulfate solution and stripping solution are obtained through oil removal.

8. A nickel sulfate / cobalt solution, characterized in that Prepared by the method according to any one of claims 1 to 7.

9. A manganese sulfate solution, characterized in that Prepared by the method according to any one of claims 1 to 7.

10. A ternary cathode material precursor, characterized in that: Prepared from the nickel sulfate / cobalt solution described in claim 8.

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