A method for processing waste lithium-ion battery powder

Abstract

The present invention discloses a method for processing waste lithium-ion battery powder, comprising ball-milling the waste lithium-ion battery powder to 20 to 500 meshes, and sequentially subjecting the waste lithium-ion battery powder to acid dissolution, filtration, copper recovery, oxidation, and sulfide precipitation; on the one hand, subjecting the nickel-cobalt-manganese sulfide filter residue to static oxidation, chemical oxidation, and precursor preparation; on the other hand, oxidizing a lithium iron-aluminum solution with hydrogen peroxide under acidic conditions and then adding sodium carbonate, thereby achieving the preparation of lithium carbonate; and evaporating, crystallizing, and drying the wastewater and washing water in the reaction process to obtain anhydrous sodium sulfate, and obtaining sodium sulfide by fully reacting anhydrous sodium sulfate with carbon at high temperature. The present invention aims to achieve the recovery of copper, iron, and aluminum through the coordinated design of multiple redox reactions, as well as the preparation of lithium carbonate and ternary battery material precursors, and also achieve the recycling of sodium sulfide, thereby improving the effective utilization rate of waste batteries.

Description

Technical Field

[0001] The present invention relates to the technical field of lithium ion batteries, and in particular to a method for processing waste lithium ion battery powder. Background Art

[0002] Currently, the content of metals such as nickel, cobalt, manganese, and lithium in lithium-ion batteries is far higher than the grade of naturally occurring ore. The cost of recycling these batteries is far lower than that of processing the original ore. Recycling spent lithium-ion batteries also reduces environmental pollution, bringing significant economic and social benefits. Existing technologies for recycling spent lithium-ion batteries generally employ processes such as pyrolysis, crushing, sorting, leaching, impurity removal, nickel-cobalt-manganese extraction, and precursor synthesis. These processes often employ extraction techniques, typically using extractants, organic solvents, sodium hydroxide, and hydrochloric acid. This process generates a certain amount of organic volatiles and wastewater, which impact the environment. While existing technologies achieve some success through the use of environmental protection facilities, these processes are costly and the effective utilization rate of spent batteries is low. Consequently, there is an urgent need for a new method for treating spent lithium-ion battery powder. Summary of the Invention

[0003] The main purpose of the present invention is to provide a method for treating waste lithium-ion battery powder, aiming to solve the technical problems of existing waste battery treatment methods such as high treatment cost and low effective utilization rate.

[0004] To achieve the above object, the present invention provides a method for treating waste lithium-ion battery powder, the method comprising the following steps:

[0005] Step 1, ball-grinding the waste lithium-ion battery powder to 20-500 mesh;

[0006] Step 2: adding water to the ball-milled battery powder to prepare a slurry to obtain a mixed slurry 1, and adjusting the pH of the mixed slurry 1 to 1.0-2.0 with a sulfuric acid solution, stirring and reacting for 0.5-5 hours, and filtering to obtain a leachate A containing nickel, cobalt, manganese, aluminum and copper ions and a corresponding filter residue B;

[0007] Step 3, adding iron powder to the leachate A, filtering to obtain a filtrate C after copper removal and copper slag;

[0008] Step 4, adding a preset amount of oxidant to the filtrate C to convert the divalent iron in the filtrate C into trivalent iron, and obtaining a mixed solution D containing trivalent iron;

[0009] Step 5: adding sodium sulfide to the mixed solution D while stirring, and filtering to obtain a lithium iron aluminum solution and a sulfide salt residue containing nickel, cobalt and manganese elements;

[0010] Step 6, leaving the filter residue in step 5 in a preset humidity environment for 15 to 120 days to allow the filter residue to be oxidized;

[0011] Step 7, adding water to the filter residue after standing in step 6 to prepare a slurry to obtain a mixed slurry 2, adding sulfuric acid to the mixed slurry 2, introducing oxygen or adding hydrogen peroxide to react for 1 to 4 hours, filtering to obtain a nickel-cobalt-manganese solution and a corresponding filter residue E, wherein the filter residue E is returned to step 6 for further processing;

[0012] Step 8, adding a preset amount of one or two of nickel sulfate, cobalt sulfate or manganese sulfate to the nickel-cobalt-manganese solution to obtain solution F;

[0013] Step 9, adding solution F and 15% to 30% sodium hydroxide by mass into the reactor simultaneously, adjusting the pH in the reactor to maintain at 9.0 to 12.5, and controlling the temperature of the reactor to be 60 to 95° C., and reacting for a preset time to obtain an initial battery material precursor and wastewater 1;

[0014] Step 10: The initial battery material precursor is washed with nickel-cobalt-manganese hydroxide and dried to obtain the target product of the ternary battery material precursor.

[0015] Optionally, the method further includes:

[0016] Step 11, adding a certain amount of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 3.5-5, and then filtering to obtain iron aluminum filter residue and lithium-containing solution;

[0017] Step 12: adding a saturated sodium carbonate solution to the lithium-containing solution, and filtering to obtain lithium carbonate precipitate and wastewater 2.

[0018] Optionally, the method further includes:

[0019] Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate;

[0020] In step 14, the prepared anhydrous sodium sulfate is mixed with carbon, and reacted at 100-500° C. for a preset time to obtain sodium sulfide, and the prepared sodium sulfide is returned to step 5 for continued use.

[0021] Optionally, in step 2, the ball-milled battery powder is slurried with water at a mass solid-to-liquid ratio of 1:2 to 1:7 to obtain a mixed slurry 1.

[0022] Optionally, in step 3, the mass of the added iron powder is 0.9-1.2 times the mass of the copper in the leaching solution A.

[0023] Optionally, in step 4, the oxidant may be an oxidant solution of a certain solubility, and oxygen may be introduced into the filtrate C, wherein the oxidant solution includes at least one of sodium chlorate, hydrogen peroxide and sodium hypochlorite solution.

[0024] Optionally, in step 7, the filter residue after standing in step 6 is slurried with pure water at a mass solid-to-liquid ratio of 1:3 to 1:10 to obtain a mixed slurry 2.

[0025] Optionally, in step 8, the molar ratio of nickel, cobalt and manganese is (2-8):(1-2):(1-3).

[0026] Optionally, the concentration of sulfuric acid in step 2 is 30%-98%.

[0027] The present invention proposes a method for treating waste lithium-ion battery powder, which separates the components in the waste battery into a soluble lithium iron aluminum solution and a nickel cobalt manganese sulfide filter residue by ball-milling the waste lithium-ion battery powder to 20-500 meshes, and sequentially performing acid dissolution, filtration, copper recovery, oxidation and sulfide precipitation. On the one hand, the nickel cobalt manganese sulfide filter residue is subjected to static oxidation, chemical oxidation and precursor preparation, thereby realizing the preparation of a ternary or dual battery material precursor, reducing the preparation cost of the battery precursor material, and the filter residue generated in the chemical oxidation can be repeatedly subjected to static oxidation treatment, thereby improving the reuse of the waste residue. On the other hand, the lithium iron aluminum solution is subjected to hydrogen peroxide oxidation treatment under acidic conditions. The recovery of iron and aluminum is achieved, and a saturated sodium carbonate solution is added to the filtrate to thereby achieve the preparation of lithium carbonate, thereby reducing the preparation cost of lithium carbonate. Furthermore, by evaporating, crystallizing, and drying the wastewater and washing water in the reaction process, anhydrous sodium sulfate is recovered. The sodium sulfide obtained by sufficient reaction with carbon at high temperature can be used as an additive material in the aforementioned treatment to separate the various components in waste batteries. Therefore, the entire process steps achieve the recovery of copper, iron, and aluminum through the coordinated design of multiple redox reactions, and can also prepare lithium carbonate and precursors for ternary or dual battery materials. Furthermore, the recycling of sodium sulfide is achieved, thereby increasing the utilization rate of waste batteries and reducing cost investment. Furthermore, the entire process does not require extraction operations, avoiding the use of extractants and organic solvents, effectively reducing the use of auxiliary materials such as sodium hydroxide, hydrochloric acid, and sulfuric acid. The entire treatment process is simple and convenient to operate, and has little environmental impact. DETAILED DESCRIPTION

[0028] It should be understood that the specific embodiments described herein are only used to explain the present invention and are not intended to limit the present invention.

[0029] The present invention provides a method for treating waste lithium-ion battery powder, which includes the following steps:

[0030] In step 1, waste lithium-ion battery powder is ball-milled to a size of 20 to 500 meshes, wherein the waste lithium-ion batteries include various types of waste lithium-ion batteries, and after the waste lithium-ion batteries are ground, the waste lithium-ion batteries mainly contain one or more metals selected from the group consisting of nickel, cobalt, manganese, aluminum, and copper.

[0031] Step 2: The ball-milled battery powder is slurried with water in a mass solid-liquid ratio of 1:2 to 1:7 to obtain a mixed slurry 1, and a certain amount of sulfuric acid is added to the mixed slurry, and the pH in the mixed slurry is controlled to be 1.0 to 2.0. The mixture is stirred and reacted for 0.5-5 hours. After the reaction is completed, the mixture is filtered to obtain a leachate A containing nickel, cobalt, manganese, aluminum, iron and copper ions and a corresponding filter residue B; the addition of sulfuric acid is used to adjust the pH value of the mixed slurry 1 on the one hand, and on the other hand to achieve the reaction and dissolution of the battery components insoluble in water in the battery powder with sulfuric acid for further extraction in subsequent processes. The mass concentration of sulfuric acid is 30% to 98%.

[0032] Step 3: Add a preset mass of iron powder to the leachate A, and filter to obtain a filtrate C after copper removal and copper slag. Specifically, the iron powder is added to displace the copper in the filtrate A, thereby realizing the recovery of copper elements in waste batteries. The activity of other metal ions is stronger than that of metallic iron, and thus they are still retained in the leachate A as metal ions. Generally, the mass of the added iron powder is 0.9-1.2 times the mass of the copper in the solution. The reaction chemical formula of the iron powder and the copper ion is as follows:

[0033] Fe+Cu 2+ =Fe 2+ +Cu.

[0034] Step 4: adding a preset amount of oxidant to the filtrate C to oxidize the divalent iron in the filtrate C to trivalent iron, and finally obtaining a mixed solution D containing trivalent iron; wherein the oxidant can be an oxidant solution of a certain solubility, and oxygen can also be introduced into the filtrate C, wherein the oxidant solution includes at least one of sodium chlorate, hydrogen peroxide and sodium hypochlorite solution.

[0035] Step 5: Add an appropriate amount of sodium sulfide to the mixed solution D while stirring, wherein the reaction process in the mixed solution D is as follows:

[0036] 2Fe 3+ +Na2S=2Fe 2+ +2Na + +S↓;

[0037] Ni 2+ +Na2S=2Na + +NiS↓;

[0038] Co 2+ +Na2S=2Na + +CoS↓;

[0039] Mn 2+ +Na2S=2Na + +MnS↓;

[0040] The filtrate is then filtered to obtain a filter residue containing sulfide salts of nickel, cobalt, and manganese. Since an appropriate amount of sodium sulfide is added, the mixed solution contains both divalent iron ions and trivalent iron ions. In an acidic environment, the aluminum element exists in the mixed solution D in the form of aluminum ions, and lithium ions do not react with sodium sulfide. Therefore, the filtrate after the filtration treatment is a mixed solution mainly containing cations such as Li+, Fe2+, Fe3+, and Al3+.

[0041] Step 6: Wash the filter residue in step 5 with pure water 2 to 4 times, grind the filter residue and place it in a certain humidity environment for 15 to 120 days to allow the nickel cobalt manganese sulfide to be oxidized in a humid environment; in addition, a certain amount of water can be sprayed on the solid surface of the nickel cobalt manganese sulfide regularly during the standing process to ensure that the nickel cobalt manganese sulfide filter residue remains moist.

[0042] Step 7, slurrying the filter residue after standing in step 6 with pure water at a mass solid-liquid ratio of 1:3-1:10 to obtain a mixed slurry 2, and adding sulfuric acid to the mixed slurry 2, passing oxygen or adding a certain amount of hydrogen peroxide to react for 1 to 4 hours, the purpose of which is to further oxidize the nickel, cobalt, and manganese elements in the mixed slurry 2 by oxygen or hydrogen peroxide and dissolve them in the mixed slurry 2, and obtain a nickel-cobalt-manganese solution and a corresponding filter residue E after filtration, wherein the filter residue E contains a portion of sulfide salts containing nickel, cobalt, and manganese elements, and the filter residue E can be returned to step 6 for further processing;

[0043] Step 8, adding a preset amount of at least one of nickel sulfate, cobalt sulfate, and manganese sulfate to the nickel-cobalt-manganese solution to obtain a solution F, so that the molar ratio of nickel, cobalt, and manganese in the mixed solution F is (1-8):(1-2):(1-3), preferably, the molar ratio of nickel, cobalt, and manganese is 1:1:1, 5:2:3, 6:2:2, or 8:1:1;

[0044] Step 9, adding solution F and 15% to 30% sodium hydroxide by mass into the reactor simultaneously, adjusting the pH in the reactor to maintain at 9.0 to 12.5, and controlling the temperature of the reactor to be 60-95° C., reacting for 1 to 6 hours, and filtering to obtain the initial battery material precursor and wastewater 1;

[0045] In step 10, the initial battery material precursor is washed with nickel-cobalt-manganese hydroxide and dried to obtain the target product of the ternary battery material precursor, thereby realizing the preparation of the ternary battery material precursor.

[0046] Furthermore, the method further comprises:

[0047] Step 11, adding a certain amount of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 3.5-5, and then filtering to obtain iron aluminum slag and lithium-containing solution, thereby realizing the recovery of iron and aluminum;

[0048] In step 12, sodium carbonate powder is added to the lithium-containing solution, and after filtering, lithium carbonate precipitate and wastewater 2 are obtained, thereby realizing the recovery of lithium carbonate.

[0049] Furthermore, the method further comprises:

[0050] Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate;

[0051] In step 14, the prepared anhydrous sodium sulfate is mixed with carbon and reacted at 100-500° C. for 20-60 minutes to obtain sodium sulfide, which can be returned to step 5 to achieve recycling of the sodium sulfide.

[0052] The present invention proposes a method for treating waste lithium-ion battery powder, which separates the components in the waste battery into a soluble lithium iron aluminum solution and a nickel cobalt manganese sulfide filter residue by ball-milling the waste lithium-ion battery powder to 20-500 meshes, and sequentially performs acid dissolution, filtration, copper removal, oxidation and sulfide precipitation; on the one hand, the nickel cobalt manganese sulfide filter residue is subjected to static oxidation, chemical oxidation and precursor preparation, thereby realizing the preparation of a ternary battery material precursor, reducing the preparation cost of the battery precursor material, and the filter residue generated in the chemical oxidation can be repeatedly subjected to static oxidation treatment, thereby improving the reuse of the waste residue; on the other hand, the lithium iron aluminum solution is subjected to hydrogen peroxide oxidation treatment under acidic conditions. The process achieves the recovery of iron and aluminum, and adds a saturated sodium carbonate solution to the filtrate to produce lithium carbonate, thereby reducing the production cost of lithium carbonate. The wastewater and washing water from the reaction process are evaporated, crystallized, and dried to recover anhydrous sodium sulfate. The sodium sulfide produced by sufficient reaction with carbon at high temperature can be used as an additive in the aforementioned treatment to separate the various components in the waste battery. Therefore, the entire process, through the coordinated design of multiple redox reactions, achieves the recovery of copper, iron, and aluminum, and can also produce lithium carbonate and ternary battery material precursors. It also achieves the recycling of sodium sulfide, thereby increasing the effective utilization rate of waste batteries. Furthermore, the entire process does not require extraction, avoiding the use of extractants and organic solvents, effectively reducing the use of auxiliary materials such as sodium hydroxide, hydrochloric acid, and sulfuric acid. The entire process is simple and convenient to operate, and has low environmental impact.

[0053] Example 1

[0054] Step 1, ball-grinding the waste lithium-ion battery powder to 20-100 mesh;

[0055] Step 2: The ball-milled battery powder is slurried with water at a mass solid-liquid ratio of 1:2 to obtain a mixed slurry 1, and a sulfuric acid solution with a mass concentration of 30% is added to the mixed slurry. The pH of the mixed slurry is controlled to 1.0, and the mixture is stirred for 0.5 hours. After the reaction is completed, the mixture is filtered to obtain a leachate A containing nickel, cobalt, manganese, aluminum, and copper ions and a corresponding filter residue B;

[0056] Step 3: Add a preset mass of iron powder to the leachate A, and filter to obtain a filtrate C after copper removal and copper slag, wherein the mass of the added iron powder is 0.9 times the mass of the copper in the solution.

[0057] Step 4, adding sodium chlorate and hydrogen peroxide solution to the filtrate C to oxidize the divalent iron in the filtrate C to trivalent iron, and finally obtaining a mixed solution D containing trivalent iron;

[0058] Step 5, adding an appropriate amount of sodium sulfide to the mixed solution D while stirring, and then filtering to obtain a lithium iron aluminum solution and a sulfide salt residue containing nickel, cobalt and manganese elements, wherein the lithium iron aluminum solution contains both divalent iron ions and trivalent iron ions;

[0059] Step 6, washing the filter residue in step 5 with pure water 2 to 4 times, grinding the nickel cobalt manganese sulfide filter residue and placing it in a certain humidity environment for 60 days to allow the nickel cobalt manganese sulfide to be oxidized in the humid environment;

[0060] Step 7: slurrying the filter residue after standing in step 6 with pure water at a mass solid-liquid ratio of 1:3 to obtain a mixed slurry 2, adding a sulfuric acid solution to the mixed slurry 2, continuously introducing oxygen to react for 1 hour, and filtering to obtain a nickel-cobalt-manganese solution and a corresponding filter residue E, wherein the filter residue E can be returned to step 6 for further processing;

[0061] Step 8, adding a preset amount of at least one of nickel sulfate, cobalt sulfate and manganese sulfate to the nickel-cobalt-manganese solution to obtain a solution F, wherein the molar ratio of nickel, cobalt and manganese in the mixed solution F is 5:2:3;

[0062] Step 9, adding solution F and 15% by mass of sodium hydroxide to the reactor simultaneously, adjusting the pH in the reactor to maintain at 9.0, and controlling the temperature of the reactor to 60° C., reacting for 6 hours, and filtering to obtain the initial battery material precursor and wastewater 1;

[0063] Step 10: The initial battery material precursor is washed with nickel-cobalt-manganese hydroxide and dried to obtain the target product of the ternary battery material precursor.

[0064] Step 11, adding a certain concentration of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 3.5, and then filtering to obtain iron aluminum slag and lithium-containing solution;

[0065] Step 12: adding sodium carbonate powder to the lithium-containing solution, and filtering to obtain lithium carbonate precipitate and wastewater 2.

[0066] Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate;

[0067] In step 14, the prepared anhydrous sodium sulfate is fully mixed with carbon and reacted at 100° C. for 1 hour to obtain sodium sulfide, which can be returned to step 5 to achieve recycling of the sodium sulfide.

[0068] Example 2

[0069] Step 1, ball-grinding the waste lithium-ion battery powder to 50-200 mesh;

[0070] Step 2: The ball-milled battery powder is slurried with water at a mass solid-liquid ratio of 1:4 to obtain a mixed slurry 1, and a sulfuric acid solution with a mass concentration of 80% is added to the mixed slurry. The pH of the mixed slurry is controlled to 1.5, and the mixture is stirred for 3 hours. After the reaction is completed, the mixture is filtered to obtain a leachate A containing nickel, cobalt, manganese, aluminum, and copper ions and a corresponding filter residue B;

[0071] Step 3: Add a preset mass of iron powder to the leachate A, and filter to obtain a filtrate C after copper removal and copper slag, wherein the mass of the added iron powder is 1.1 times the mass of the copper in the solution.

[0072] Step 4: introducing a certain amount of oxygen into the filtrate C to oxidize the divalent iron in the filtrate C into trivalent iron, thereby finally obtaining a mixed solution D containing trivalent iron;

[0073] Step 5: adding an appropriate amount of sodium sulfide to the mixed solution D while stirring, and then filtering to obtain a lithium iron aluminum solution and a nickel cobalt manganese sulfide filter residue, wherein the lithium iron aluminum solution contains both divalent iron ions and trivalent iron ions;

[0074] Step 6: Wash the filter residue in step 5 with pure water for 2 to 4 times and let it stand for 15 days. During the standing period, spray a certain amount of water on the solid surface of nickel cobalt manganese sulfide regularly to ensure that the filter surface of nickel cobalt manganese sulfide remains moist.

[0075] Step 7: slurrying the filter residue after standing in step 6 with pure water at a mass solid-liquid ratio of 1:5 to obtain a mixed slurry 2, adding a sulfuric acid solution to the mixed slurry 2, continuously introducing oxygen to react for 2 hours, and filtering to obtain a nickel-cobalt-manganese solution and a corresponding filter residue E, wherein the filter residue E can be returned to step 6 for further processing;

[0076] Step 8, adding a preset amount of one or two of nickel sulfate, cobalt sulfate and manganese sulfate to the nickel-cobalt-manganese solution to obtain a solution F, wherein the molar ratio of nickel, cobalt and manganese in the mixed solution F is 6:2:2;

[0077] Step 9, adding solution F and 20% by mass of sodium hydroxide to the reactor simultaneously, adjusting the pH in the reactor to maintain at 10.0, and controlling the temperature of the reactor to 70° C., reacting for 4 hours, and filtering to obtain the initial battery material precursor and wastewater 1;

[0078] In step 10, the initial battery material precursor is washed and dried with nickel-cobalt-manganese hydroxide to obtain the target product of ternary or binary battery material precursor, thereby realizing the preparation of ternary battery material precursor.

[0079] Step 11, adding a certain concentration of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 4, and then filtering to obtain iron aluminum slag and lithium-containing solution;

[0080] Step 12: adding a saturated sodium carbonate solution to the lithium-containing solution, filtering to obtain lithium carbonate precipitate and wastewater 2, thereby realizing the recovery of lithium carbonate.

[0081] Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate;

[0082] In step 14, the prepared anhydrous sodium sulfate is fully mixed with carbon, and reacted at 200° C. for 40 minutes to obtain sodium sulfide, which can be returned to step 5 to achieve recycling of the sodium sulfide.

[0083] Example 3

[0084] Step 1, ball-grinding the waste lithium-ion battery powder to 20-500 mesh;

[0085] Step 2: The ball-milled battery powder is slurried with water at a mass solid-liquid ratio of 1:7 to obtain a mixed slurry 1, and a sulfuric acid solution with a mass concentration of 98% is added to the mixed slurry. The pH of the mixed slurry is controlled to 2.0, and the reaction is stirred for 5 hours. After the reaction is completed, the leaching solution A containing nickel, cobalt, manganese, aluminum, iron and copper ions and the corresponding filter residue B are obtained.

[0086] Step 3: Add a preset mass of iron powder to the leachate A, and filter to obtain a filtrate C after copper removal and copper slag, wherein the mass of the added iron powder is 1.2 times the mass of the copper in the solution.

[0087] Step 4: adding a preset amount of hydrogen peroxide and sodium hypochlorite solution to the filtrate C to oxidize the divalent iron in the filtrate C to trivalent iron, and finally obtaining a mixed solution D containing trivalent iron.

[0088] Step 5: adding an appropriate amount of sodium sulfide to the mixed solution D while stirring, and then filtering to obtain a lithium iron aluminum solution and a nickel cobalt manganese sulfide filter residue, wherein the lithium iron aluminum solution contains both divalent iron ions and trivalent iron ions;

[0089] Step 6: Wash the filter residue in step 5 with pure water for 2 to 4 times, grind the nickel cobalt manganese sulfide filter residue and place it in a certain humidity environment for 120 days to allow the nickel cobalt manganese sulfide to be oxidized in the humid environment.

[0090] Step 7, slurrying the filter residue after standing in step 6 with pure water at a mass solid-liquid ratio of 1:10 to obtain a mixed slurry 2, and continuously adding a certain amount of sulfuric acid and hydrogen peroxide solution to the mixed slurry 2 to react for 2 hours, and filtering to obtain a nickel-cobalt-manganese solution and the corresponding filter residue E, wherein the filter residue E can be returned to step 6 for further processing;

[0091] Step 8, adding a preset amount of at least one of nickel sulfate, cobalt sulfate, and manganese sulfate to the nickel-cobalt-manganese solution to obtain a solution F, wherein the molar ratio of nickel, cobalt, and manganese in the mixed solution F is 8:1:1;

[0092] Step 9, adding solution F and 30% by mass of sodium hydroxide to the reactor simultaneously, adjusting the pH in the reactor to maintain at 12.5, and controlling the temperature of the reactor to 95° C., reacting for 1 hour, and filtering to obtain the initial battery material precursor and wastewater 1;

[0093] Step 10: The initial battery material precursor is washed and dried with nickel-cobalt-manganese hydroxide to obtain the target product of the ternary battery material precursor.

[0094] Step 11, adding a certain concentration of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 5, and then filtering to obtain iron aluminum slag and lithium-containing solution;

[0095] In step 12, sodium carbonate powder is added to the lithium-containing solution, and after filtering, lithium carbonate precipitate and wastewater 2 are obtained, thereby realizing the recovery of lithium carbonate.

[0096] Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate;

[0097] In step 14, the prepared anhydrous sodium sulfate is mixed with carbon and reacted at 500° C. for 20 minutes to obtain sodium sulfide. The sodium sulfide can be returned to step 5 to achieve recycling of the sodium sulfide.

[0098] In addition, in order to better illustrate the effect of the treatment method of the present invention, the purity of the lithium carbonate recovered in Example 1 is as follows:

[0099] Table 1 Purity of the recovered lithium carbonate

[0100]

[0101] As shown in Table 1 above, the purity of the lithium carbonate in Example 1 meets the requirements of the YS / T582-2006 battery grade standard for the quality of lithium carbonate. The process steps adopted in Examples 2-3 are basically the same as those in Example 1, and the purity of the lithium carbonate finally obtained also basically meets the YS / T582-2006 battery grade standard.

[0102] Furthermore, the following is done by making corresponding batteries from the ternary battery material precursors prepared in Examples 1-3 to determine whether the corresponding battery performance meets the basic battery requirements, as follows:

[0103] The ternary battery material precursor and lithium carbonate obtained in Examples 1-3 were weighed to 12 kg and 6 kg respectively, and added to a ball mill for mixing. The ball milling speed was 220 r / min, the ball milling time was 1 h, and the ball milling medium was polyurethane balls to obtain a mixture. The mixture was then placed in a tube furnace and heated to 600 ° C at a heating rate of 5 ° C / min, pre-sintered at low temperature for 4 h, and then heated to 950 ° C at a heating rate of 5 ° C / min for high-temperature sintering for 16 h. The sintering atmosphere was air, and the mixture was naturally cooled to room temperature. The cooled sintered sample was mechanically crushed and manually sieved to obtain the comparative example of nickel cobalt manganese oxide positive electrode material. The obtained nickel cobalt manganese oxide positive electrode materials and negative electrode sheets were made into corresponding batteries 1-3, each of which was 10 batteries, according to the conventional battery preparation process. The prepared batteries were subjected to corresponding performance tests, as follows:

[0104] Standard charging method: The standard charging method for each of the 10 batteries in Examples 1-3 is to charge at a current of 0.2C to a limit voltage of 4.2V at an ambient temperature (25±5°C), and then change to constant voltage charging until the cutoff current reaches 0.001C and stop charging.

[0105] Table 2 Performance test of batteries prepared from precursors of Examples 1-3

[0106]

[0107] As can be seen from Table 2 above, the batteries made from the precursor materials prepared in Examples 1-3 meet the industry battery standards, which shows that the recycling method of the present invention is effective.

[0108] It should be noted that, in this document, the terms "comprises," "includes," or any other variations thereof are intended to encompass non-exclusive inclusion, such that a process, method, article, or system comprising a series of elements includes not only those elements but also other elements not explicitly listed, or elements inherent to such process, method, article, or system. In the absence of further limitations, an element defined by the phrase "comprising a ..." does not exclude the presence of other identical elements in the process, method, article, or system comprising the element.

[0109] The serial numbers of the above embodiments of the present invention are for description only and do not represent the advantages or disadvantages of the embodiments.

Claims

1. A method for treating waste lithium-ion battery powder, characterized in that: The method comprises the following steps: Step 1, ball-grinding the waste lithium-ion battery powder to 20-500 mesh; Step 2: adding water to the ball-milled battery powder to prepare a slurry to obtain a mixed slurry 1, and adjusting the pH of the mixed slurry 1 to 1.0-2.0 with a sulfuric acid solution, stirring and reacting for 0.5-5 hours, and filtering to obtain a leachate A containing nickel, cobalt, manganese, aluminum, iron and copper ions and a corresponding filter residue B; Step 3, adding iron powder to the leachate A, filtering to obtain a filtrate C after copper removal and copper slag; Step 4, adding a preset amount of oxidant to the filtrate C to convert the divalent iron in the filtrate C into trivalent iron, and obtaining a mixed solution D containing trivalent iron; Step 5: adding sodium sulfide to the mixed solution D while stirring, and filtering to obtain a lithium iron aluminum solution and a sulfide salt residue containing nickel, cobalt and manganese elements; Step 6, leaving the filter residue in step 5 in a preset humidity environment for 15 to 120 days to oxidize the nickel cobalt manganese sulfide filter residue; Step 7, adding water to the filter residue after standing in step 6 to prepare a slurry to obtain a mixed slurry 2, adding sulfuric acid to the mixed slurry 2, introducing oxygen or adding hydrogen peroxide to react for 1 to 4 hours, filtering to obtain a nickel-cobalt-manganese solution and a corresponding filter residue E, wherein the filter residue E is returned to step 6 for further processing; Step 8, adding a preset amount of at least one of nickel sulfate, cobalt sulfate and manganese sulfate to the nickel-cobalt-manganese solution to obtain a solution F, so that the molar ratio of nickel, cobalt and manganese in the mixed solution F is (2-8):(1-2):(1-3); Step 9, adding solution F and 15% to 30% sodium hydroxide by mass into the reactor simultaneously, adjusting the pH in the reactor to maintain at 9.0 to 12.5, and controlling the temperature of the reactor to be 60 to 95° C., and reacting for a preset time to obtain an initial battery material precursor and wastewater 1; Step 10: The initial battery material precursor is washed with nickel-cobalt-manganese hydroxide and dried to obtain the target product of the ternary battery material precursor.

2. The method for processing waste lithium-ion battery powder according to claim 1, wherein: The method further comprises: Step 11, adding a certain amount of hydrogen peroxide and sodium hydroxide solution to the lithium iron aluminum solution prepared in step 5, and adjusting the pH value to 3.5-5, and then filtering to obtain iron aluminum filter residue and lithium-containing solution; Step 12: adding sodium carbonate to the lithium-containing solution, and filtering to obtain lithium carbonate precipitate and wastewater 2.

3. The method for processing waste lithium-ion battery powder according to claim 2, further comprising: Step 13, the wastewater 1 in step 9, the washing water in step 10, and the wastewater 2 in step 12 are evaporated, crystallized, and dried to obtain anhydrous sodium sulfate; In step 14, the prepared anhydrous sodium sulfate is mixed with carbon, and reacted at 100-500° C. for a preset time to obtain sodium sulfide, and the prepared sodium sulfide is returned to step 5 for continued use.

4. The method for processing waste lithium-ion battery powder according to any one of claims 1 to 3, characterized in that: In the step 2, the ball-milled battery powder is slurried with water at a mass solid-to-liquid ratio of 1:2 to 1:7 to obtain a mixed slurry 1.

5. The method for processing waste lithium-ion battery powder according to any one of claims 1 to 3, characterized in that: In step 3, the mass of the added iron powder is 0.9-1.2 times the mass of the copper in the leaching solution A.

6. The method for treating waste lithium-ion battery powder according to any one of claims 1 to 3, characterized in that: In step 4, the oxidant is an oxidant solution of a preset solubility or oxygen directly introduced into the filtrate C, wherein the oxidant solution includes at least one of sodium chlorate, hydrogen peroxide and sodium hypochlorite solution.

7. The method for treating waste lithium-ion battery powder according to any one of claims 1 to 3, characterized in that: In the step 7, the filter residue after standing in step 6 is slurried with pure water at a mass solid-liquid ratio of 1:3 to 1:10 to obtain a mixed slurry 2.

8. The method for treating waste lithium-ion battery powder according to any one of claims 1 to 3, characterized in that: The concentration of sulfuric acid in step 2 is 30% to 98%.

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