A method for recycling and processing waste ternary lithium batteries

Abstract

This invention relates to a method for recycling and processing waste ternary lithium batteries. The recycling and processing method includes: discharging and disassembling the waste batteries to obtain positive electrode sheets; removing the binder on the positive electrode sheets using an organic solvent and then separating them to obtain a positive electrode current collector and initial positive electrode powder; removing the conductive agent from the initial positive electrode powder using flotation to obtain pretreated positive electrode powder; and using a mixture of acid and oxidant as a leaching solution, leaching the pretreated positive electrode powder in the leaching solution to obtain a leachate, wherein the leachate contains Mn. 2+ Co 2+ Ni 2+ and Li + The invention employs a selective precipitation method to extract and separate manganese dioxide, cobalt salts, nickel salts, and lithium salts from the leachate, thereby achieving the separation and recovery of manganese, cobalt, nickel, and lithium in the cathode material of lithium batteries. This invention effectively recycles spent ternary lithium batteries and reduces secondary pollution.

Description

Technical Field

[0001] This invention relates to the field of waste ternary lithium battery recycling technology, specifically to a method for recycling and processing waste ternary lithium batteries. Background Technology

[0002] In recent years, lithium-ion batteries have been widely used in industries such as mobile electronic devices, new energy and hybrid vehicles, and grid energy storage due to their advantages such as low self-discharge rate and long service life. Lithium-ion battery production has experienced explosive growth. Taking 2023 as an example, my country's total lithium battery production exceeded 940 GWh, a year-on-year increase of 25%, with a total industry output value exceeding 1.4 trillion yuan. From January to December, the production of consumer-grade, power-grade, and energy storage lithium batteries were 80 GWh, 675 GWh, and 185 GWh, respectively. The installed capacity of lithium batteries (including new energy vehicles and new energy storage) exceeded 435 GWh, and export trade increased by more than 33% year-on-year.

[0003] The number of retired commercial power lithium batteries on the market is enormous. Direct disposal without recycling would result in significant waste and environmental pollution. Most of the cost and recyclable value of lithium batteries is concentrated in the cathode, typically made of lithium iron phosphate (LiFePO4, LFP), lithium cobalt oxide (LiCoO2, LCO), or lithium nickel cobalt manganese oxide (LiNi). x CoyMn (1-x-y) O2 (or NCM for short), among others, ternary NCM materials have become the mainstream cathode material for new energy vehicles due to their advantages such as high energy density, high specific capacity, and long lifespan. They are also the most common positive electrode material for lithium batteries on the market. It is estimated that by 2050, the number of battery-powered passenger vehicles will exceed 100 million. Waste ternary lithium batteries contain large amounts of metals such as nickel, cobalt, manganese, and lithium, which have high recycling value. Since 2019, the prices of raw materials used to produce lithium-ion battery cathodes, especially lithium and cobalt, have risen sharply over the years. The cost of positive electrode materials accounts for more than half of the total cost of all components. The weight percentages of cobalt, nickel, manganese, and lithium in NCM are 5-20%, 5-12%, 7-10%, and 2-5%, respectively, exceeding the content of natural ores. If valuable metal elements in waste lithium-ion batteries cannot be effectively recycled and reused, then relying solely on natural mineral resources to meet the future market demand for lithium battery positive electrode materials will be a huge challenge. The recycling of valuable metals from spent lithium batteries helps alleviate the depletion of strategic metal resources and reduces battery production costs, which is of great significance to environmental and economic sustainable development. Furthermore, spent lithium batteries contain many harmful chemicals, such as fluorides and organic matter; effective recycling is also an urgent need to achieve carbon neutrality. Therefore, recycling spent ternary lithium batteries can effectively alleviate resource shortages and protect the environment.

[0004] Currently, the commonly used methods for recycling valuable metals from spent lithium-ion battery cathode materials are mainly divided into pyrometallurgy and hydrometallurgy. Pyrometallurgy involves directly heating the battery in a high-temperature furnace, causing the combustion of materials such as plastics, organic matter, and graphite. The high temperature promotes the reduction of metals such as cobalt, nickel, and copper, which alloy with the help of reducing agents (such as aluminum foil, anode graphite, and introduced carbon). Simultaneously, lithium, manganese, and aluminum are entrained in the slag. While pyrometallurgy can process spent lithium-ion batteries on a large scale, it is insufficient in recovering electrolytes, anode graphite, and valuable lithium. Furthermore, pyrometallurgy requires a large amount of energy and releases harmful gases, causing serious air pollution. Hydrometallurgy, on the other hand, involves immersing the spent cathode powder in a solution to dissolve the metals into the liquid phase, and then separating and recovering the metals through precipitation, extraction, and electrodeposition. Hydrometallurgical processes have the advantages of mild reaction conditions, environmental friendliness, and high recovery efficiency, making them the mainstream method in laboratories and industrial production. However, they can lead to the generation of acidic or alkaline wastewater, causing secondary environmental problems. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recycling and processing waste ternary lithium batteries, so as to achieve effective recycling of waste ternary lithium batteries and reduce secondary pollution.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0007] A method for recycling and processing waste ternary lithium batteries includes the following steps:

[0008] S1. Discharge and disassemble the waste battery to obtain a plastic shell, negative electrode plate, separator, positive electrode plate, battery cap and aluminum shell.

[0009] S2. After removing the binder on the positive electrode sheet with an organic solvent, the positive electrode current collector and the initial positive electrode powder are obtained.

[0010] S3. The conductive agent in the initial positive electrode powder is removed by flotation to obtain pretreated positive electrode powder;

[0011] S4. Using a mixture of acid and oxidant as the leaching solution, the pretreated positive electrode powder is placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + ;

[0012] S5. Selective precipitation of the leachate is used for extraction and separation to obtain manganese dioxide, cobalt salt, nickel salt and lithium salt, so as to realize the separation and recovery of manganese, cobalt, nickel and lithium in the positive electrode material of lithium battery.

[0013] Based on the aforementioned technical methods, the environmental pollution that may be caused during the processing of waste batteries is effectively avoided through the discharge and dismantling steps. Removing binders with organic solvents and removing conductive agents by flotation enables efficient separation of the cathode material, thereby improving the recovery rate of metal resources. Selective precipitation extraction of the leachate allows for precise separation of manganese, cobalt, nickel, and lithium, achieving effective recovery of these valuable resources. Through these steps, high-purity manganese dioxide, cobalt oxalate, nickel salts, and lithium carbonate can be obtained, which can be used to produce new battery materials or for other industrial applications. This method not only reduces environmental pollution but also recovers valuable metal resources, resulting in significant economic and social benefits.

[0014] Preferably, S5 includes:

[0015] S51. Add potassium permanganate to the leachate, stir and react under the first temperature condition, keep warm and age, filter, and obtain manganese dioxide precipitate and first filtrate.

[0016] S52. Adjust the pH of the first filtrate to neutral, add the mixed extractant, shake, and let stand to obtain a solution containing Co. 2+ oil phase and containing Ni 2+ and Li + The aqueous phase contains Co 2+ The oil phase was back-extracted to obtain a product containing Co. 2+ The aqueous phase, wherein the mixed extractant is a mixture of P507 extractant and sulfonated kerosene;

[0017] S53, Adjusting the content of Co 2+ The aqueous phase was brought to neutral, sodium oxalate solution was added, the reaction was stirred, and the mixture was allowed to react. After precipitation, the mixture was filtered to obtain cobalt oxalate precipitate. The solution containing Ni was then added. 2+ and Li + Sodium hydroxide solution was added to the aqueous phase, the mixture was stirred and reacted, and after filtration, nickel hydroxide and a third filtrate were obtained.

[0018] S54. Add sodium carbonate solution to the third filtrate, stir to react, react, filter, and obtain lithium carbonate precipitate.

[0019] By adding potassium permanganate to the leachate, manganese in the leachate is converted into manganese dioxide precipitate, thereby achieving manganese separation and recovery. By adjusting the pH to neutral and using a specific mixed extractant (a mixture of P507 extractant and sulfonated kerosene), cobalt, nickel, and lithium can be efficiently separated, achieving enrichment of each metal. Reacting sodium oxalate solution with an aqueous phase containing Co2+ yields high-purity cobalt oxalate precipitate, which is beneficial for the subsequent preparation of cobalt products. (Containing Ni) 2+ and Li +By adding sodium hydroxide solution to the aqueous phase, nickel hydroxide and a third filtrate can be obtained, thus separating nickel and lithium. Finally, adding sodium carbonate solution to the third filtrate can efficiently precipitate lithium carbonate from the solution, which is beneficial for the recovery and utilization of lithium resources. The entire process, through temperature control, pH adjustment, and the use of extractants, achieves efficient separation and recovery of multiple metals, improving resource utilization. This method has clear operating steps, mild reaction conditions, and is conducive to industrial application and environmental friendliness.

[0020] P507 extractant is a colorless or pale yellow transparent oily liquid with the following structural formula: .

[0021] Preferably, in step S51, potassium permanganate reacts with Mn in the leachate. 2+ The molar ratio is 1~2.

[0022] Preferably, in step S51, the first temperature is 50~70℃.

[0023] Preferably, in S53, sodium oxalate and a compound containing Co 2+ The molar ratio in the aqueous phase is n[C2O4] 2- ]:n[Co 2+ The value is estimated to be 0.8~1.2.

[0024] Preferably, in step S53, the material containing Ni is... 2+ and Li + Sodium hydroxide solution is added to the aqueous phase to make the pH of the solution 8-12.

[0025] Preferably, in step S54, sodium carbonate reacts with Li in the third filtrate. + The molar ratio of n[CO3] 2- ]:n[Li + The value is estimated to be 0.5~0.9.

[0026] Preferably, S5 includes:

[0027] S501. Add potassium permanganate to the leachate, stir and react under the first temperature condition, keep warm and age, filter, and obtain manganese dioxide precipitate and first filtrate.

[0028] S502. Dissolve dimethylglyoxime (DMG) in ethanol, then add the first filtrate, adjust the pH to acidic, stir the reaction, keep warm and age, and filter to obtain nickel precipitate of dimethylglyoxime and the fifth filtrate.

[0029] S503. Adjust the pH of the fifth filtrate to neutral, add the mixed extractant, shake, and let stand to obtain a solution containing Co. 2+ oil phase and containing Li+ The aqueous phase contains Co 2+ The oil phase was back-extracted to obtain a product containing Co. 2+ The aqueous phase, wherein the mixed extractant is a mixture of P507 extractant and sulfonated kerosene;

[0030] S504, Adjusting the content of Co 2+ The aqueous phase was brought to neutral, sodium oxalate solution was added, the reaction was stirred, and the mixture was filtered to obtain cobalt oxalate precipitate.

[0031] S505, To contain Li + Sodium carbonate solution was added to the aqueous phase, the mixture was stirred to react, and after filtration, lithium carbonate precipitate was obtained.

[0032] The use of potassium permanganate can effectively oxidize impurities in the leachate, improving the purity of manganese dioxide precipitate. Dimethylglyoxime (DMG), as a precipitant, can efficiently form a precipitate with nickel ions, thereby achieving nickel separation and recovery. Adjusting the pH to acidic can optimize the precipitation reaction conditions of DMG-Ni, improving precipitation efficiency and purity. Using a mixed extractant (P507 extractant and sulfonated kerosene) for extraction can effectively separate cobalt and lithium, achieving separate recovery of the two metals. Sodium oxalate solution with Co... 2+ The aqueous phase reaction yields high-purity cobalt oxalate precipitate, providing a raw material for subsequent cobalt product preparation. Sodium carbonate solution reacts with Li... + The aqueous phase reaction can efficiently prepare lithium carbonate precipitate, providing an effective way to recover lithium resources. Throughout the process, the reaction can be optimized by adjusting pH and temperature conditions, thereby improving metal recovery rate and product purity. This method achieves efficient recovery of multiple metals through chemical reaction and separation technology, and has high industrial application value.

[0033] Preferably, in step S501, potassium permanganate reacts with Mn in the leachate. 2+ The molar ratio is 1~2.

[0034] Preferably, in S501, the first temperature is 50~70℃.

[0035] Preferably, in step S502, the molar ratio of dimethylglyoxime (DMG) to the first filtrate is n[DMG]:n[Ni] 2+ The value is estimated to be 1.6~2.4.

[0036] Preferably, the pH value of S502 is 1 to 5.

[0037] Preferably, in S504, sodium oxalate and a compound containing Co 2+ The molar ratio in the aqueous phase is n[C2O4] 2- ]:n[Co 2+The value is estimated to be 0.8~1.2.

[0038] Preferably, in S505, sodium carbonate and a substance containing Li + The molar ratio of the aqueous phase to n[CO3] 2- ]:n[Li + The value is estimated to be 0.5~0.9.

[0039] Preferably, in step S2, the organic solvent is selected from dimethylacetamide (DMAC), and the solid-liquid ratio of the positive electrode to dimethylacetamide (DMAC) is 25~45 g / L.

[0040] Preferably, in step S2, ultrasonic-assisted removal of the adhesive on the positive electrode sheet is combined, wherein the power of the ultrasonic wave is 800~900W and the duration of the ultrasonic wave is 30~110min.

[0041] Preferably, step S2 further includes recovering the dimethylacetamide (DMAC) solution obtained after removing the adhesive on the positive electrode sheet using an organic solvent. The recovery method is as follows: the dimethylacetamide (DMAC) solution is distilled at a temperature of 175~185°C to obtain a dimethylacetamide (DMAC) distillate, which is then recycled to remove the adhesive on the positive electrode sheet.

[0042] Preferably, in step S3, dibromomethane is used as a flotation agent to remove the conductive agent from the initial positive electrode powder.

[0043] The beneficial effects of this invention are:

[0044] The recycling method for spent ternary lithium batteries of this invention effectively avoids environmental pollution that may be caused during the processing of spent batteries through discharge and dismantling steps. Removing binders with organic solvents and removing conductive agents by flotation enables efficient separation of the cathode material, thereby improving the recovery rate of metal resources. Selective precipitation is used to extract and separate the leachate, precisely separating manganese, cobalt, nickel, and lithium, achieving effective recovery of these valuable resources. Through the above steps, high-purity manganese dioxide, cobalt oxalate, nickel salts, and lithium carbonate can be obtained, which can be used to produce new battery materials or for other industrial applications. This method not only reduces environmental pollution but also recovers valuable metal resources, resulting in good economic and social benefits. It has significant application value in the field of spent ternary lithium battery recycling technology. Attached Figure Description

[0045] Figure 1 This is the first flow chart of the recycling and processing method for waste ternary lithium batteries;

[0046] Figure 2This is a photograph of the initial positive electrode powder obtained in Example 1;

[0047] Figure 3 A photograph of dibromomethane separated from NCM and acetylene black under static conditions;

[0048] Figure 4 This is a photograph of the first precipitate obtained in Example 1;

[0049] Figure 5 The XRD pattern of the first precipitate obtained in Example 1;

[0050] Figure 6 This is a photograph of the second precipitate obtained in Example 1;

[0051] Figure 7 The XRD pattern of the second precipitate obtained in Example 1;

[0052] Figure 8 This is a photograph of the third precipitate obtained in Example 1;

[0053] Figure 9 The XRD pattern of the third precipitate obtained in Example 1;

[0054] Figure 10 This is a photograph of the fourth precipitate obtained in Example 1;

[0055] Figure 11 The XRD pattern of the fourth precipitate obtained in Example 1;

[0056] Figure 12 The graph shows the effect of solid-liquid ratio on the peeling effect.

[0057] Figure 13 The graph shows the effect of ultrasonic time on the peeling effect.

[0058] Figure 14 The graph shows the effect of sulfuric acid concentration on the leaching effect.

[0059] Figure 15 The graph shows the effect of hydrogen peroxide volume fraction on the leaching effect.

[0060] Figure 16 The graph shows the effect of solid-liquid ratio on leaching efficiency.

[0061] Figure 17 The graph shows the effect of leaching treatment time on the leaching effect.

[0062] Figure 18 The graph shows the effect of leaching temperature on the leaching effect.

[0063] Figure 19The effect of potassium permanganate addition on the first precipitation effect is shown in the figure.

[0064] Figure 20 The graph shows the effect of pH on the extraction efficiency.

[0065] Figure 21 The graph shows the effect of oil-water ratio on extraction efficiency.

[0066] Figure 22 The graph shows the effect of shaking time on the extraction effect.

[0067] Figure 23 The graph shows the effect of dilution factor on extraction efficiency.

[0068] Figure 24 The graph shows the effect of sodium oxalate addition on the second precipitation effect.

[0069] Figure 25 The graph shows the effect of pH on the third precipitation effect.

[0070] Figure 26 The graph shows the effect of sodium carbonate dosage on the fourth precipitation effect.

[0071] Figure 27 This is the second flow chart of the recycling and processing method for waste ternary lithium batteries;

[0072] Figure 28 This is a photograph of the fifth precipitate obtained in Example 10;

[0073] Figure 29 The XRD pattern of the fifth precipitate obtained in Example 10;

[0074] Figure 30 Figure showing the effect of DMG addition on ion precipitation rate;

[0075] Figure 31 The graph shows the effect of pH on the ion precipitation rate.

[0076] Figure 32 The effect of Na2S2O8 addition on Mn 2+ The effect of precipitation on the results;

[0077] Figure 33 pH versus Mn 2+ The effect of precipitation on the results;

[0078] Among them, 1-carbon black; 2-dibromomethane; 3-pretreated cathode powder; Detailed Implementation

[0079] The following description, with reference to preferred embodiments, illustrates the implementation of the present invention. Those skilled in the art can clearly understand other advantages and effects of the present invention from the content set forth in this specification. The present invention can also be implemented or applied through other different specific embodiments, and various details in this specification can be modified or changed based on different viewpoints and applications without departing from the spirit of the present invention. It should be understood that the preferred embodiments are merely illustrative of the present invention and not intended to limit the scope of protection of the present invention.

[0080] Example 1

[0081] like Figure 1 As shown, a method for recycling and processing waste ternary lithium batteries includes the following steps:

[0082] S1. Discharging and Manual Disassembly: Discharging and disassembling used batteries yields a plastic casing, negative electrode plate, separator, positive electrode plate, battery cap, and aluminum outer casing, specifically including:

[0083] Connect the positive and negative terminals of the used battery to a sliding rheostat, and then connect a 1A current limiter in series in the circuit to prevent excessive power. After discharging for about 24 hours, the battery voltage will drop to 0.32V. Stop discharging and begin disassembly. Place the discharged battery in a fume hood, use a small electric cutter to cut open the outer casing, and then manually separate the six components: plastic shell, negative electrode plate, separator, positive electrode plate, battery cap, and aluminum shell. The weight of each part is shown in Table 1.

[0084] Table 1. Weight and percentage of each component in a single lithium battery

[0085] S2. After removing the binder on the positive electrode sheet with an organic solvent, the mixture is separated to obtain the positive electrode current collector and the initial positive electrode powder, specifically including:

[0086] The positive electrode sheet obtained in S1 was soaked in dimethylacetamide (DMAC) and ultrasonically assisted to remove the binder (polyvinylidene fluoride, i.e., PVDF) on the positive electrode sheet. After filtration, the following were obtained: positive electrode current collector (aluminum foil), initial positive electrode powder, and dimethylacetamide (DMAC) soaking solution. The solid-liquid ratio of dimethylacetamide (DMAC) to the positive electrode sheet was 35 g / L, the ultrasonic power was 860 W, and the ultrasonic time was 110 min. The physical image of the obtained initial positive electrode powder is shown below. Figure 2 As shown;

[0087] S3. The conductive agent in the initial positive electrode powder is removed by flotation to obtain pretreated positive electrode powder, specifically including:

[0088] Using dibromomethane as the organic solvent, the initial positive electrode powder obtained in S2 was added to dibromomethane, stirred evenly, and allowed to stand for 2 hours. Figure 3 As shown, in a static state, the upper layer is carbon black 1, the middle layer is dibromomethane 2, and the lower layer is pretreated positive electrode powder 3. The upper layer of carbon black 1 is sucked out with a dropper, and then the pretreated positive electrode powder 3 and dibromomethane 2 are separated by filtration to achieve three-phase separation. The dibromomethane 2 obtained by filtration separation is recycled.

[0089] S4. Using a mixture of acid and oxidant as the leaching solution, the pretreated positive electrode powder is placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + Specifically, it includes:

[0090] Using a mixture of sulfuric acid and hydrogen peroxide as the leaching solution, the pretreated positive electrode powder 3 obtained in S3 was placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + ,

[0091] The leaching solution contained sulfuric acid at a concentration of 2.5 M and hydrogen peroxide at a volume percentage of 6%. The solid-liquid ratio of the leaching solution to the pretreated cathode powder 3 was 15 g / L. The leaching temperature was 60 °C and the leaching time was 120 min.

[0092] S5. Selective precipitation and extraction separation of the leachate yields manganese dioxide, cobalt oxalate, nickel hydroxide, and lithium carbonate, thereby achieving the separation and recovery of manganese, cobalt, nickel, and lithium in the cathode material of lithium batteries. Specifically, this includes:

[0093] S51. Add the leachate obtained in S4 and potassium permanganate to the reaction vessel. Then place the reaction vessel on a magnetic stirrer, set the heating temperature to 60℃ and the stirring speed to 200 r / min, react for 0.5 h, and then keep it at this temperature for 1 h. Filter the mixture using a vacuum filtration apparatus to obtain the first precipitate and the first filtrate. After filtration, rinse the reaction vessel and the first precipitate 3-4 times with hot water, and include the rinsing liquid in the first filtrate. The amount of potassium permanganate added is based on the amount of Mn in the leachate. 2+ Based on, n[Mn 2 + The ratio of [KMnO4] to [KMnO4] is 1:1.5; the physical image of the first precipitate is shown below. Figure 4 As shown, the first precipitate was analyzed by XRD, and the results are as follows. Figure 5 As shown; from Figure 5Analysis showed that the peak positions and peak heights of the XRD pattern of the first precipitate were basically consistent with those in the manganese dioxide standard card, thus proving that the first precipitate was mainly MnO2 and had a relatively complete crystal form; the X-ray diffractometer was X'Pert PRO MPD, the analysis conditions were Cu target, the test angle 2θ was 5°~90°, and the scanning speed was 2° / min;

[0094] S52. Adjust the pH of the first filtrate obtained in S51 to 6.5, then add the mixed extraction solvent, shake for 8 minutes, let stand and separate the contents to obtain the solution containing Co. 2+ The oil and water phases are used to achieve Co 2+ with Ni 2+ Li + The separation and extraction were performed using a 1.5M sulfuric acid solution to treat the Co-containing sample. 2+ The oil phase was back-extracted, with an oil-to-water ratio of 1:1, and the shaking time was 8 minutes, so that Co 2+ From the organic phase into the aqueous phase, a substance containing Co was obtained. 2+ The aqueous phase; wherein the extractant is a mixture of P507 extractant and sulfonated kerosene in a volume ratio of 1:4, and the mixture was saponified before use; the oil-water ratio (volume ratio of extractant to first filtrate) is 1:1;

[0095] S53, the Co-containing compound obtained in S52 2+ The aqueous phase was placed in a reaction vessel, and the pH was adjusted to neutral by adding dilute sulfuric acid or sodium hydroxide solution. Then, sodium oxalate solution was added, and the reaction vessel was placed on a magnetic stirrer. The temperature was set to room temperature and the stirring speed to 200 rpm. After reacting for 0.5 hours, the mixture was aged for 1 hour. The mixture was then filtered using a vacuum filtration apparatus to obtain a second precipitate and a second filtrate. After filtration, the reaction vessel and the second precipitate were rinsed 3-4 times with ultrapure water, and the rinsing liquid was included in the second filtrate. The amount of sodium oxalate added was based on the Co content... 2+ Co in the aqueous phase 2+ Based on n[C2O4] 2- ]:n[Co 2+ The ratio was 1.1:1; the physical image of the resulting second precipitate is shown below. Figure 6 As shown, the second precipitate was dried in an oven at 50°C, ultimately yielding pink cobalt oxalate powder; the second precipitate was analyzed by XRD, and the results are as follows. Figure 7 As shown; from Figure 7 Analysis shows that the second precipitate is CoC2O4∙H2O. The elution positions and heights of the main peaks are basically the same as those of the standard card, and there are no impurity peaks. It can be determined that the reaction produced a single phase of CoC2O4∙H2O.

[0096] S54. Place the aqueous phase from S52 into a reaction vessel, add sodium hydroxide solution to make the pH 11, then place the reaction vessel on a magnetic stirrer, set the temperature to room temperature and the stirring speed to 200 r / min, react for 0.5 h, then age for 1 h, and then filter using a vacuum filtration apparatus to obtain the third precipitate and the third filtrate. After filtration, rinse the reaction vessel and the third precipitate 3-4 times with ultrapure water, and include the rinsing liquid in the third filtrate; the actual image of the obtained third precipitate is shown below. Figure 8 As shown, the third precipitate was dried in an oven at 50°C, ultimately yielding green nickel hydroxide powder; the third precipitate was analyzed by XRD, and the results are as follows. Figure 9 As shown; from Figure 9 Analysis shows that the peak position and peak height of the third precipitate are basically consistent with the standard spectrum of nickel hydroxide, and there are relatively few impurity peaks, indicating that the product is relatively pure Ni(OH)2.

[0097] S55. Place the third filtrate obtained in S54 into a reaction vessel, add sodium carbonate solution, and then place the reaction vessel on a magnetic stirrer. Set the temperature to room temperature and the stirring speed to 200 r / min. React for 0.5 h, then age for 1 h. Filter using a vacuum filtration apparatus to obtain the fourth precipitate and the fourth filtrate. After filtration, rinse the reaction vessel and the fourth precipitate 3-4 times with 90℃ ultrapure water, and include the rinsing liquid in the fourth filtrate. The physical image of the obtained fourth precipitate is shown below. Figure 10 As shown, the fourth precipitate is a white lithium carbonate powder; XRD analysis of the fourth precipitate yielded the following results. Figure 11 As shown; from Figure 11 Analysis shows that the fourth precipitate is Li2CO3. The elution positions and heights of the main peaks are basically the same as those of the standard card, and there are no impurity peaks. It can be determined that the reaction produced a single phase of Li2CO3.

[0098] After a series of separation, extraction, and precipitation experiments, the final recovery rates of the four metals, lithium, nickel, cobalt, and manganese, are shown in Table 2.

[0099] Table 2 Final recovery rates of each metal

[0100]

[0101] Example 2

[0102] This embodiment investigated the effects of the solid-liquid ratio of dimethylacetamide (DMAC) to the positive electrode and the ultrasonic time on the purity of the positive electrode current collector (aluminum foil) and the peeling efficiency of the adhesive. The settings of the solid-liquid ratio and ultrasonic time, as well as the test results, are shown in Table 3. Figure 12 and Figure 13 As shown. The steps and parameter conditions in the remaining S1 and S2 are the same as in Example 1.

[0103] Table 3. Effects of solid-liquid ratio and ultrasonic time on peeling effect

[0104]

[0105] From Table 2 and Figure 12 As can be seen, with the increase of the solid-liquid ratio, the purity and peeling efficiency of the positive electrode current collector (aluminum foil) will decrease.

[0106] From Table 2 and Figure 13 As can be seen, with the increase of ultrasonic time, the purity and peeling efficiency of the positive current collector (aluminum foil) gradually increase, reaching 93.60% and 98.90% respectively when the ultrasonic time is 110 min.

[0107] Example 3

[0108] The recovery treatment of the dimethylacetamide (DMAC) immersion solution obtained in S2 of Example 1 includes:

[0109] The distillation temperature was controlled between 180℃ ± 5℃ using a distillation apparatus until no residual liquid remained at the bottom of the flask. The volume of the solution before distillation was 780 mL, and after distillation it was 760 mL, with a recovery rate of 96.15%. A yellow film-like PVDF solid was found at the bottom of the flask after distillation.

[0110] The initial positive electrode powder obtained in S2 of Example 1 was soaked in DMAC for 2 hours, and the resulting dimethylacetamide (DMAC) soaking solution was filtered and then distilled again. After evaporation to dryness, no yellow solid residue remained at the bottom of the flask, which proved that the polyvinylidene fluoride (PVDF) on the positive electrode sheet had completely dissolved in DMAC during the ultrasonic process and had no residue on the surface of the positive electrode powder.

[0111] The DMAC obtained by distillation was subjected to aluminum foil peeling test under the same conditions as S1 and S2 in Example 1. The purity of the obtained positive current collector (aluminum foil) was 94.6% and the peeling efficiency was 97.2%, which proved that the separation effect of the distilled DMAC was still very good and could be recycled.

[0112] Example 4

[0113] This embodiment investigated the concentrations of sulfuric acid and hydrogen peroxide in the leachate, the solid-liquid ratio of the leachate to the pretreated cathode powder 3, and the effects of leaching temperature and time on the concentration of Mn in the leachate. 2+ Co 2+ Ni 2+ and Li + The effects of leaching rate were considered, and the steps and parameters in S1, S2, and S3 were the same as in Example 1. After each reaction, the volume of the leachate was brought to 50 mL, diluted, and the concentration of each ion was tested using ICP. The results are as follows: Figures 14 to 18As shown, three parallel sample measurements were performed each time. Figures 14 to 18 It is the average value of three parallel samples taken for each ion.

[0114] from Figures 14 to 18 Analysis shows that the concentrations of sulfuric acid and hydrogen peroxide in the leachate, the solid-liquid ratio of the leachate to the pretreated cathode powder, and the temperature and time of the leaching process all affect the concentration of Mn in the leachate. 2+ Co 2+ Ni 2+ and Li + The leaching rate is affected by all factors. Specifically, when the leaching time is 120 min, the sulfuric acid concentration is 2.5 M, the reaction temperature is 60 °C, the hydrogen peroxide volume fraction is 6%, and the solid-liquid ratio is 15 g / L, the Mn content in the leachate is significantly affected. 2+ Co 2+ Ni 2+ and Li + The leaching rates of the four metal ions were 99.8%, 99.6%, 99.9%, and 99.1%, respectively. The contents of the four metal ions in the leachate were 0.761 g / L, 5.213 g / L, 2.016 g / L, and 2.667 g / L, respectively.

[0115] Example 5

[0116] This embodiment investigated the effect of KMnO4 addition amount on Mn 2+ The effects of precipitation were not considered; the steps and parameters in S1, S2, S3, S4, and S51 were the same as in Example 1. The first filtrate from S51 was diluted to 100 mL each time, and the nickel, cobalt, manganese, and lithium contents were tested using ICP-MS. Each experiment was performed in triplicate, and the test results are shown below. Figure 19 As shown.

[0117] from Figure 19 Analysis shows that when n(Mn) 2+ When the KMnO4 value is between 1 and 1.5, the manganese content in the solution continuously decreases, and at this point, most of the manganese in the solution is in the form of Mn. 2+ The presence of Mn in this form is due to the insufficient amount of potassium permanganate added, which is not enough to completely precipitate the Mn in the solution. 2+ ; and when n(Mn) 2+ When the KMnO4 value is between 1.5 and 2, the manganese content in the solution continuously increases, and at this time, most of the manganese in the solution is in the form of MnO4. - The presence of MnO4 in this form is due to the addition of excess potassium permanganate to the solution. - The remaining amount, and the slightly reduced cobalt content, may be due to its relationship with MnO4. - A reaction occurred, and the content of lithium and nickel did not decrease significantly throughout the entire reaction process.

[0118] The formula for calculating the metal leaching rate η is shown in Equation I:

[0119] (I)

[0120] In Formula I, C1 represents the concentration of metal ions in the filtrate (mg / L); V1 represents the volume of the filtrate (L); C2 represents the concentration of metal ions in the filter residue (mg / L); and V2 represents the volume of the filter residue solution (L).

[0121] Metal precipitation rate P Me The calculation formula is shown in Equation II:

[0122] (II)

[0123] In Formula II, C3 represents the concentration of metal ions before precipitation (mg / L); C4 represents the concentration of metal ions after precipitation (mg / L).

[0124] Example 6

[0125] This embodiment investigated the effects of the pH value of the first filtrate, the oil-to-water ratio (volume ratio of extractant to first filtrate), shaking time, and the volume ratio of P507 extractant to sulfonated kerosene in the mixed extractant on the extraction efficiency. The steps and parameters in S1, S2, S3, S4, S51, and S52 were the same as in Example 1. After dilution of the aqueous phase obtained in each S52 step, the concentrations of lithium, nickel, and cobalt in the aqueous phase were measured using ICP-MS to calculate the extraction rate. The results are shown below. Figures 20 to 23 As shown.

[0126] Among them, the extraction rate E Me The formulas for calculating the back-extraction rate are shown in Equations III and IV;

[0127] (III)

[0128] (IV)

[0129] In Equations III and IV, C a V represents the concentration of metal ions in the aqueous phase after extraction (mg / L); a Indicates the volume of the aqueous phase after extraction (L); C b V represents the concentration of metal ions in the solution before extraction (mg / L); b Indicates the volume of the solution before extraction (L); C m V represents the concentration of metal ions in the solution after back-extraction (mg / L); m Indicates the volume of the solution after back-extraction (L); C nV represents the concentration of metal ions in the organic phase before back-extraction (mg / L); n This indicates the volume (L) of the organic phase before back-extraction.

[0130] from Figure 20 Analysis shows that the extraction rates of all three metals increase with increasing pH, because H... + Reducing the pH can promote the reaction and thus drive the extraction process. At pH 4.5, the extraction rates of cobalt, nickel, and lithium were 63.72%, 10.44%, and 1.66%, respectively. When the pH increased to 6.5, the extraction rates were 95.30%, 22.03%, and 3.19%, respectively. Most of the cobalt in the solution was extracted into the organic phase, along with some nickel and a small amount of lithium. When the pH continued to rise to 7.0, the cobalt extraction rate slowed down, increasing only from 95.30% to 95.87%, while the nickel extraction rate increased from 20.54% to 36.38%, and the lithium extraction rate increased from 3.19% to 4.48%. This shows that simply increasing the pH does not ensure complete extraction of cobalt and also allows a large amount of nickel to enter the organic phase, reducing the purity of the cobalt.

[0131] from Figure 21 Analysis shows that the oil-to-water ratio has a significant impact on the metal extraction rate. Under otherwise constant conditions, the extraction rate E increases with increasing O / A ratio. When O / A = 0.5, the extraction rates of cobalt, nickel, and lithium are 71.73%, 1.15%, and 0.99%, respectively. As O / A increases, the extraction rates of all three metals also increase. When O / A = 1.0, the extraction rates of cobalt, nickel, and lithium are 95.31%, 22.03%, and 3.19%, respectively. With further increases in O / A, the extraction rate of cobalt slows down and no longer shows a significant increase, while the extraction rates of nickel and lithium increase considerably. This significantly reduces the purity of cobalt in the organic phase. Therefore, the optimal oil-to-water ratio is 1:1.

[0132] from Figure 22 Analysis shows that with increasing shaking time, the contact between the organic and aqueous phases becomes more complete. Therefore, the extraction rates E of all three metals increase with prolonged shaking time, with cobalt and nickel showing a more significant effect. When the shaking time is 2 min, the extraction rates of cobalt, nickel, and lithium are 51.55%, 10.96%, and 0.54%, respectively. However, when the shaking time is 8 min, the extraction rates of cobalt, nickel, and lithium are 95.31%, 22.03%, and 3.19%, respectively.

[0133] from Figure 23Analysis shows that, compared with the other three factors, the dilution factor of P507 (i.e., the volume ratio of P507 to sulfonated kerosene) has a relatively small impact on the extraction rates of the three metals. However, it can also be seen that as the dilution factor of P507 increases, the extraction rates of the three metals all tend to decrease. This is because the higher the content of P507, the more it promotes the extraction reaction. When the dilution factor is 5 (i.e., the volume ratio of P507 to sulfonated kerosene is 1:5), the extraction rates of cobalt, nickel, and lithium are 89.52%, 19.46%, and 2.6%, respectively. When the dilution factor decreases to 4, the extraction rates of cobalt, nickel, and lithium are 95.31%, 22.03%, and 3.19%, respectively. As the dilution factor continues to decrease, the extraction rate of cobalt tends to stabilize, while the extraction rate of nickel increases significantly.

[0134] Example 7

[0135] This embodiment investigated the effect of sodium oxalate addition on Mn. 2+ The effects of precipitation were not considered; the steps and parameters in S1, S2, S3, S4, S51, S52, and S53 were the same as in Example 1. The second filtrate obtained in S53 was diluted to 100 mL each time, and the cobalt content was tested using ICP-MS. The cobalt precipitation rate was calculated. Each experiment was performed in triplicate, and the results are as follows: Figure 24 As shown.

[0136] from Figure 24 Analysis shows that as the amount of sodium oxalate added increases, Co... 2+ The precipitation rate is also constantly increasing, when n[C2O4] 2- ]:n[Co 2+ When ]=0.8:1, Co 2+ The precipitation rate was 73.3%, while when n[C2O4] 2- ]:n[Co 2+ When the ratio rises to 1.1:1, Co 2+ The precipitation rate can reach 97.87%, when n[C2O4] 2- ]:n[Co 2+ When ]=1.2:1, Co 2+ The sedimentation rate was 98.32%, and there was no further significant increase.

[0137] Example 8

[0138] This embodiment investigated the effect of pH value on Ni. 2+ The effects of precipitation were not considered; the steps and parameters in S1, S2, S3, S4, S51, S52, and S54 were the same as in Example 1. The third filtrate from S54 was diluted to 100 mL each time, and the nickel and lithium content was tested using ICP-MS. The precipitation rates of nickel and lithium were calculated. Each experiment was performed in triplicate, and the results are as follows: Figure 25 As shown.

[0139] from Figure 25 Analysis shows that as the pH increases from 8 to 11, the nickel precipitation rate also increases from 86.1% to 98.17%. When the pH increases to 12, the nickel precipitation rate is 98.70%, which is not significantly improved. At the same time, although the pH keeps increasing, the lithium loss rate remains stable below 0.5%, indicating that the nickel precipitation process does not affect lithium, and also indicating that the recovered nickel hydroxide has high purity.

[0140] Example 9

[0141] This embodiment investigated the effect of sodium carbonate dosage on Li + The effects of precipitation were not considered; the steps and parameters in S1, S2, S3, S4, S51, S52, S54, and S55 were the same as in Example 1. The fourth filtrate obtained in S55 was diluted to 100 mL each time, and the lithium content was tested using ICP-MS. The lithium precipitation rate was calculated. Each experiment was performed in triplicate, and the results are as follows: Figure 26 As shown.

[0142] from Figure 26 Analysis shows that when n[CO3] 2- ]:n[Li + When n[CO3] = 0.5, the lithium precipitation rate is only 64.45%. With the continuous addition of sodium carbonate, the lithium precipitation rate increases. 2- ]:n[Li + When n[CO3] = 0.8, the lithium precipitation rate increases to 95.38%, while when n[CO3] = 0.8, the precipitation rate increases to 95.38%. 2- ]:n[Li + When the concentration continues to rise to 0.9, the lithium precipitation rate increases significantly to 96.26%.

[0143] Example 10

[0144] like Figure 27 As shown, a method for recycling and processing waste ternary lithium batteries includes the following steps:

[0145] S1. Discharging and Manual Disassembly: Discharging and disassembling used batteries yields a plastic casing, negative electrode plate, separator, positive electrode plate, battery cap, and aluminum outer casing, specifically including:

[0146] Connect the positive and negative terminals of the used battery to a sliding rheostat, and then connect a 1A current limiter in series in the circuit to prevent excessive power. After discharging for about 24 hours, the battery voltage will drop to 0.32V. Stop discharging and begin disassembly. Place the discharged battery in a fume hood, use a small electric cutter to cut open the outer casing, and then manually separate the six components: plastic shell, negative electrode plate, separator, positive electrode plate, battery cap, and aluminum outer shell.

[0147] S2. After removing the binder on the positive electrode sheet with an organic solvent, the mixture is separated to obtain the positive electrode current collector and the initial positive electrode powder, specifically including:

[0148] The positive electrode sheet obtained by soaking S1 in dimethylacetamide (DMAC) and combined with ultrasound assistance were used to remove the binder (polyvinylidene fluoride, i.e., PVDF) on the positive electrode sheet. After filtration, the positive electrode current collector (aluminum foil), initial positive electrode powder and dimethylacetamide (DMAC) soaking solution were obtained. The solid-liquid ratio of dimethylacetamide (DMAC) to the positive electrode sheet was 35 g / L, the ultrasonic power was 860 W and the ultrasonic time was 110 min.

[0149] S3. The conductive agent in the initial positive electrode powder is removed by flotation to obtain pretreated positive electrode powder, specifically including:

[0150] Using dibromomethane as the organic solvent, the initial positive electrode powder obtained in S2 was added to dibromomethane, stirred evenly, and allowed to stand for 2 hours. Figure 3 As shown, in a static state, the upper layer is carbon black 1, the middle layer is dibromomethane 2, and the lower layer is pretreated positive electrode powder 3. The upper layer of carbon black 1 is sucked out with a dropper, and then the pretreated positive electrode powder 3 and dibromomethane 2 are separated by filtration to achieve three-phase separation. The dibromomethane 2 obtained by filtration separation is recycled.

[0151] S4. Using a mixture of acid and oxidant as the leaching solution, the pretreated positive electrode powder is placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + Specifically, it includes:

[0152] Using a mixture of sulfuric acid and hydrogen peroxide as the leaching solution, the pretreated positive electrode powder 3 obtained in S3 was placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + ,

[0153] The leaching solution contained sulfuric acid at a concentration of 2.5 M and hydrogen peroxide at a volume percentage of 6%. The solid-liquid ratio of the leaching solution to the pretreated cathode powder 3 was 15 g / L. The leaching temperature was 60 °C and the leaching time was 120 min.

[0154] S5. Selective precipitation and extraction separation of the leachate yields manganese dioxide, cobalt oxalate, nickel dimethylglyoxime, and lithium carbonate, achieving the separation and recovery of manganese, cobalt, nickel, and lithium in the cathode material of lithium batteries. Specifically, this includes:

[0155] S501. Add the leachate obtained in S4 and potassium permanganate to the reaction vessel, then place the reaction vessel on a magnetic stirrer, set the heating temperature to 60℃ and the stirring speed to 200r / min, react for 0.5h, then keep it at the temperature for 1h, and then filter it using a vacuum filter to obtain the first precipitate and the first filtrate. After filtration, rinse the reaction vessel and the first precipitate with hot water 3-4 times, and include the rinsing liquid in the first filtrate.

[0156] S502. Dimethylglyoxime (DMG) powder is dissolved in anhydrous ethanol and added to the reaction vessel along with the first filtrate obtained in S501. The pH of the solution is adjusted to 3 using NaOH or dilute H2SO4 solution. The reaction vessel is then placed on a magnetic stirrer, with the heating temperature set to 60℃ and the stirring speed to 200 r / min. After reacting for 0.5 h, the mixture is kept at this temperature for 1 h. The mixture is then filtered using a vacuum filtration apparatus to obtain the fifth precipitate and the fifth filtrate. After filtration, the reaction vessel and the fifth precipitate are rinsed 3-4 times with distilled water, and the rinsing liquid is added to the fifth filtrate. A photograph of the obtained fifth precipitate is shown below. Figure 28 As shown, the fifth precipitate is a rose-red nickel butanedione oxime powder; the results of XRD analysis of the fifth precipitate are as follows. Figure 29 As shown; from Figure 29 Analysis shows that the peak position and intensity are close to those of the standard card, indicating that the nickel butyrone oxime produced in the experiment has a complete crystal form. The narrow and high peaks in the XRD pattern indicate that the sample has high crystallinity and large diameter. The absence of impurity peaks indicates that the produced butyrone oxime has high purity.

[0157] S503. Adjust the pH of the fifth filtrate obtained from S502 to 6.5, then add the mixed extraction solvent, shake for 8 minutes, allow to stand and separate, to obtain the solution containing Co. 2+ The oil and water phases are used to achieve Co 2+ with Ni 2+ Li + The separation and extraction were performed using a 1.5M sulfuric acid solution to treat the Co-containing sample. 2+ The oil phase was back-extracted, with an oil-to-water ratio of 1:1, and the shaking time was 8 minutes, so that Co 2+ From the organic phase into the aqueous phase, a substance containing Co was obtained. 2+The aqueous phase; wherein the extractant is a mixture of P507 extractant and sulfonated kerosene in a volume ratio of 1:4, and the mixture was saponified before use; the oil-water ratio (volume ratio of extractant to first filtrate) is 1:1;

[0158] S504, the Co-containing compound obtained in S503 2+ The aqueous phase was placed in a reaction vessel, and the pH was adjusted to neutral by adding dilute sulfuric acid or sodium hydroxide solution. Then, sodium oxalate solution was added, and the reaction vessel was placed on a magnetic stirrer. The temperature was set to room temperature and the stirring speed to 200 rpm. After reacting for 0.5 hours, the mixture was aged for 1 hour. The mixture was then filtered using a vacuum filtration apparatus to obtain the sixth precipitate and the sixth filtrate. After filtration, the reaction vessel and the sixth precipitate were rinsed 3-4 times with ultrapure water, and the rinsing liquid was included in the sixth filtrate. The amount of sodium oxalate added was based on the Co content... 2+ Co in the aqueous phase 2+ Based on n[C2O4] 2- ]:n(Co 2+ The ratio was 1.1:1; the physical image of the sixth precipitate is shown below. Figure 6 As shown, the sixth precipitate was dried in an oven at 50°C, and finally pink cobalt oxalate powder was obtained.

[0159] S505. Place the aqueous phase from S503 into a reaction vessel, add sodium carbonate solution, and then place the reaction vessel on a magnetic stirrer. Set the temperature to room temperature and the stirring speed to 200 r / min. React for 0.5 h, then age for 1 h. Filter using a vacuum filtration apparatus to obtain the seventh precipitate and the seventh filtrate. After filtration, rinse the reaction vessel and the seventh precipitate 3-4 times with 90℃ ultrapure water, and include the rinsing liquid in the seventh filtrate. The physical image of the obtained seventh precipitate is shown below. Figure 10 As shown, the seventh precipitate is a white lithium carbonate powder.

[0160] Example 11

[0161] This embodiment investigated the effect of the amount of dimethylglyoxime (DMG) added on Ni 2+ The effects of precipitation were minimized, and the steps and parameters in S1, S2, S3, S4, S501, and S502 were the same as in Example 10. The fifth filtrate obtained each time was diluted to 100 mL, and the nickel, cobalt, and lithium contents were tested using ICP-MS. The precipitation rates of nickel, cobalt, and lithium were calculated. Each experiment was performed in triplicate, and the results are as follows: Figure 30 As shown.

[0162] from Figure 30 Analysis shows that when n(DMG: Ni) 2+ When )=1.6, Ni 2+ The precipitation rate was 79.9%. With the increase of DMG addition, Ni...2+ The precipitation rate also increases as n(DMG: Ni) 2+ When )=2, Ni 2+ The precipitation rate increased to 99.17%, indicating almost complete precipitation, while the loss rates of lithium and cobalt were 0.43% and 0.8%, respectively. As the molar ratio of the two continued to increase, Ni... 2+ The sedimentation rate no longer increased significantly.

[0163] Example 12

[0164] This embodiment investigated the effect of pH on Ni. 2+ The effects of precipitation were minimized, and the steps and parameters in S1, S2, S3, S4, S501, and S502 were the same as in Example 10. The fifth filtrate obtained each time was diluted to 100 mL, and the nickel, cobalt, and lithium contents were tested using ICP-MS. The precipitation rates of nickel, cobalt, and lithium were calculated. Each experiment was performed in triplicate, and the results are as follows: Figure 31 As shown.

[0165] from Figure 31 Analysis shows that when pH=1, Ni 2+ The precipitation rate was 74.47%. As pH increased, Ni... 2+ The precipitation rate also increases accordingly, because of the low H... + Concentration favors the forward reaction of 4.10; when pH=3, Ni 2+ The precipitation rate was 99.17%, and the losses of lithium and cobalt were 0.43% and 0.8%, respectively. With further increase in pH, Ni... 2+ The increase in precipitation rate was not significant, while Co 2+ The loss rate, however, increased slightly, because a small portion of Co... 2+ The precipitate forms Co(OH)2, resulting in Co 2+ The concentration decreased.

[0166] Comparative Example 1

[0167] In this embodiment, Na2S2O8 was used instead of KMnO4, and the effect of the amount of Na2S2O8 added on Mn was investigated. 2+ The effects of precipitation were not considered; the steps and parameters in S1, S2, S3, S4, and S51 were the same as in Example 1. The first filtrate from S51 was diluted to 100 mL each time, and the nickel, cobalt, manganese, and lithium contents were tested using ICP-MS. Each experiment was performed in triplicate, and the test results are shown below. Figure 32 As shown.

[0168] from Figure 32Analysis shows that, while maintaining the original pH of the leachate, increasing the dosage of sodium persulfate can improve the Mn content. 2+ The precipitation rate didn't help much; although the manganese content decreased slightly, even with a dosage far exceeding the theoretical value, the manganese precipitation rate was only around 20%. This was because the system's pH was too low and the H₂O was too high. + The concentration of Mn will inhibit reaction 4.2, which is unfavorable for Mn. 2+ The sedimentation.

[0169] Therefore, in n[S2O8] 2- ]:n[Mn 2+ The pH of the system was increased under the condition of ]=1.75 to investigate the effect of pH change on Mn. 2+ The effect of precipitation. Test results are as follows: Figure 33 As shown.

[0170] from Figure 33 Analysis shows that, given a fixed amount of sodium persulfate, increasing the pH of the system does indeed benefit Mn. 2+ The precipitation of manganese showed a concentration of 20.13 μg / L at pH=2. As the pH increased to 7, the manganese concentration decreased to 8.13 μg / L, and a significant increase in the weight of the precipitate was also observed. However, it is noteworthy that with increasing pH, besides Mn... 2+ S2O8 2- In addition to precipitation, Ni in the solution 2+ and Co 2+ The concentration of Ni also decreased significantly at pH=6. 2+ and Co 2+ The concentrations of Ni were 51.45 μg / L and 19.16 μg / L, respectively. However, when pH=7, the concentrations of Ni decreased to 49.92 μg / L and 17.86 μg / L, respectively. This is because as pH increases, Ni... 2+ and Co 2+ When Mn is precipitated as hydroxides, the resulting nickel hydroxide and cobalt hydroxide become impurities mixed into the manganese dioxide precipitate, reducing the purity of the product. Therefore, to completely precipitate Mn using sodium persulfate... 2+ A higher pH is required, which causes nickel hydroxide and cobalt hydroxide to precipitate simultaneously, reducing the purity of manganese dioxide. Therefore, sodium persulfate is used to oxidize and precipitate Mn. 2+ The method is not feasible in this system.

[0171] In summary, the recycling method for waste ternary lithium batteries of this invention effectively avoids environmental pollution that may be caused during the processing of waste batteries through discharge and dismantling steps. Removing binders with organic solvents and removing conductive agents by flotation enables efficient separation of the cathode material, thereby improving the recovery rate of metal resources. Selective precipitation extraction of the leachate allows for precise separation of manganese, cobalt, nickel, and lithium, achieving effective recovery of these valuable resources. Through the above steps, high-purity manganese dioxide, cobalt oxalate, nickel salts, and lithium carbonate can be obtained, which can be used to produce new battery materials or for other industrial applications. This method not only reduces environmental pollution but also recovers valuable metal resources, offering significant economic and social benefits and possessing widespread application value in the field of waste ternary lithium battery recycling technology.

[0172] The above embodiments are merely preferred embodiments provided to fully illustrate the present invention, and the scope of protection of the present invention is not limited thereto. Equivalent substitutions or modifications made by those skilled in the art based on the present invention are all within the scope of protection of the present invention.

Claims

1. A method for recycling and processing waste ternary lithium batteries, characterized in that, The cathode material is efficiently separated by removing binders with organic solvents and conductive agents by flotation; the leachate is extracted and separated by selective precipitation, enabling the separation and recovery of manganese, cobalt, nickel and lithium in the cathode material of lithium batteries. Includes the following steps: S1. Discharge and disassemble the waste battery to obtain the positive electrode sheet; S2. After removing the binder on the positive electrode sheet with an organic solvent, the positive electrode current collector and the initial positive electrode powder are obtained. S3. The conductive agent in the initial positive electrode powder is removed by flotation to obtain pretreated positive electrode powder; S4. Using a mixture of acid and oxidant as the leaching solution, the pretreated positive electrode powder is placed in the leaching solution for leaching treatment to obtain a leaching solution containing Mn. 2+ Co 2+ Ni 2+ and Li + ; S5. Selective precipitation of the leachate for extraction and separation to obtain manganese dioxide, cobalt salts, nickel salts, and lithium salts, thereby achieving the separation and recovery of manganese, cobalt, nickel, and lithium in the cathode material of lithium batteries; including: S501. Add potassium permanganate to the leachate, stir and react under the first temperature condition, keep warm and age, filter, and obtain manganese dioxide precipitate and first filtrate. S502. Dissolve dimethylglyoxime (DMG) in ethanol, then add the first filtrate, adjust the pH to acidic, stir the reaction, keep warm and age, and filter to obtain nickel precipitate of dimethylglyoxime and the fifth filtrate. S503. Adjust the pH of the fifth filtrate to neutral, add the mixed extractant, shake, and let stand to obtain a solution containing Co. 2+ oil phase and containing Li + The aqueous phase contains Co 2+ The oil phase was back-extracted to obtain a product containing Co. 2+ The aqueous phase, wherein the mixed extractant is a mixture of P507 extractant and sulfonated kerosene; S504, Adjusting the content of Co 2+ The aqueous phase was brought to neutral, sodium oxalate solution was added, the reaction was stirred, and the mixture was filtered to obtain cobalt oxalate precipitate. S505, To contain Li + Sodium carbonate solution was added to the aqueous phase, the mixture was stirred to react, and after filtration, lithium carbonate precipitate was obtained.

2. The method for recycling and processing waste ternary lithium batteries according to claim 1, characterized in that, In step S501, potassium permanganate reacts with Mn in the leachate. 2+ The molar ratio is 1~2; And / or, in S501, the first temperature is 50~70℃; And / or, in S502, the molar ratio of dimethylglyoxime (DMG) to the first filtrate is n[DMG]:n[Ni] 2+ The value is estimated to be 1.6~2.

4. And / or, in S502, the pH value is 1~5.

3. The method for recycling and processing waste ternary lithium batteries according to claim 1, characterized in that, In S504, sodium oxalate and Co-containing compounds... 2+ The molar ratio in the aqueous phase is n[C2O4] 2- ]:n[Co 2+ The value is estimated to be 0.8~1.

2. And / or, in S505, sodium carbonate reacts with a substance containing Li + The molar ratio of the aqueous phase to n[CO3] 2- ]:n[Li + The value is estimated to be 0.5~0.

9.

4. The method for recycling and processing waste ternary lithium batteries according to claim 1, characterized in that, In S2, the organic solvent is selected from dimethylacetamide (DMAC), and the solid-liquid ratio of the positive electrode to dimethylacetamide (DMAC) is 25~45 g / L; And / or, in S2, ultrasonic-assisted removal of the adhesive on the positive electrode is combined, wherein the power of the ultrasonic wave is 800~900W and the duration of the ultrasonic wave is 30~110min.

5. The method for recycling and processing waste ternary lithium batteries according to claim 4, characterized in that, S2 further includes recovering the dimethylacetamide (DMAC) solution obtained after removing the adhesive on the positive electrode sheet using an organic solvent. The recovery method is as follows: the dimethylacetamide (DMAC) solution is distilled at a temperature of 175~185℃ to obtain a dimethylacetamide (DMAC) distillate, which is then recycled to remove the adhesive on the positive electrode sheet.

6. The method for recycling and processing waste ternary lithium batteries according to claim 1, characterized in that, In step S3, dibromomethane is used as a flotation agent to remove the conductive agent from the initial positive electrode powder.

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