Waste battery recycling method

Abstract

A waste battery recycling method, belonging to the technical field of resource recycling. The waste battery recycling method comprises: leaching a lithium manganate electrode plate of a waste battery using sulfuric acid, performing ball milling with sodium dithionite, roasting with sulfur, performing water leaching, dissolving using a carboxyl-containing mixed acid solution, then using a water-retaining agent and an ethanol solution, and adjusting the pH value to 3-4.5 using a sodium hydroxide solution, to achieve hydroxylation conversion, then mixing with lithium hydroxide, and supplementing lithium with potassium permanganate for roasting to obtain Li4Mn5O12, and performing hydrochloric acid leaching to obtain a lithium ion sieve H4Mn5O12 having excellent adsorption performance.

Description

Methods for recycling waste batteries Technical Field

[0001] The present application relates to the technical field of resource recycling and utilization, and in particular to a method for recycling waste batteries. Background Art

[0002] As my country's new energy vehicle technology improves and matures, sales of lithium-ion battery-powered vehicles continue to climb. Limited by the lifespan of power batteries, the number of scrapped power batteries has also been increasing since 2020. Wasted ternary lithium-ion batteries contain a large amount of valuable metals, typically 5% to 20% Co, 5% to 10% Ni, 5% to 7% Li, and 5% to 10% other metals (Cu, Al, Fe, etc.), and have significant economic value for recycling.

[0003] Currently, waste battery recycling methods are primarily divided into dry and wet methods. The dry method is suitable for most lithium battery recycling and is currently in large-scale production. Deeply discharged batteries are crushed, magnetically separated, and finally calcined at high temperatures. However, the dry method consumes a lot of energy, requires high equipment investment, has low returns, and cannot recover valuable metals such as lithium and nickel from the lithium battery's cathode materials.

[0004] Wet recycling is a common method for recovering valuable metals from used lithium batteries. The wet recycling process can achieve a recovery rate of over 95% for valuable metals (transition metals and lithium) from used lithium batteries. Therefore, it is currently the primary process for recycling used lithium batteries. The traditional wet recycling process first discharges, crushes, sorts, and screens the used lithium batteries to produce battery powder, copper and aluminum slag, and separators. The valuable metals in the battery powder are then leached using a mixture of acid and a reducing agent.

[0005] The main steps of the wet recovery method are: first, discharge the battery, disassemble it, and crush it to obtain a positive electrode sheet containing valuable metals such as lithium, cobalt, nickel, and manganese. Then, use a polar solvent to separate the active material from the aluminum foil. Finally, use acid leaching to separate the metal ions for recovery through extraction, precipitation, or ion exchange. Wet recovery can effectively recover the valuable metals in the battery positive electrode material, maximizing resource recovery. It is simpler to operate than dry recovery and is easy to industrialize, showing great application prospects. However, the addition of acid during the recovery process has certain environmental impacts.

[0006] Lithium ion sieve is a material that selectively adsorbs lithium. As a high-value-added adsorbent, lithium ion sieve plays an important role in the extraction of lithium-containing wastewater and brine brine, and has attracted widespread attention and research. Previously developed lithium ion sieve adsorption materials mainly include manganese, titanium, aluminum salts, etc. Lithium ion sieve can be prepared by solid-phase sintering, hydrothermal, and sol-gel methods. CN108199104A discloses a method for preparing lithium ion sieve from lithium manganate battery waste and the lithium ion sieve thereof. The method prepares lithium manganate waste into lithium manganate ion sieve material by subjecting the lithium manganate waste to high-temperature heat treatment and activation pretreatment, followed by acid leaching, and then washing and drying. However, factors such as low recycling rate and long adsorption time limit its practical application in industry.

[0007] Summary of the Invention

[0008] The purpose of this application is to overcome the shortcomings of the existing technology and provide a method for recycling waste batteries. By recycling the lithium manganese oxide pole pieces of waste batteries, a lithium ion sieve H4Mn5O with excellent adsorption performance is prepared. 12 .

[0009] To achieve the above objectives, the technical solutions adopted in this application are:

[0010] A method for recycling waste batteries comprises the following steps:

[0011] The lithium manganate pole pieces of the waste battery are leached with sulfuric acid solution to obtain lithium manganite;

[0012] Mixing lithium manganite and sodium dithionite by ball milling to obtain a mixture;

[0013] The mixed material is evenly mixed with sulfur, roasted, the roasted product is soaked in water, and dried to obtain manganese oxide;

[0014] Adding manganese oxide to a carboxyl-containing mixed acid solution, and after complete dissolution, adding a water retaining agent and an ethanol solution, adding a sodium hydroxide solution to adjust the pH to 3-4.5, filtering, and drying to obtain manganese oxyhydroxide;

[0015] Mixing manganese oxyhydroxide and lithium hydroxide evenly and calcining;

[0016] The calcined product is mixed evenly with potassium permanganate and calcined to obtain Li4Mn5O 12 ;

[0017] Li4Mn5O 12 Leaching with hydrochloric acid solution to obtain lithium ion sieve H4Mn5O 12 .

[0018] The present invention involves leaching the lithium manganese oxide pole piece of waste battery with sulfuric acid, ball milling with sodium dithionite, sulfur roasting, water soaking, dissolving with carboxyl mixed acid solution, using water retaining agent and ethanol solution, and adjusting the pH to 3-4.5 with sodium hydroxide solution to achieve hydroxylation conversion, mixing with lithium hydroxide, and then roasting with potassium permanganate to obtain Li4Mn5O 12 , and then through hydrochloric acid leaching, a lithium ion sieve H4Mn5O with excellent adsorption performance was obtained. 12 (Manganese-based lithium ion sieve).

[0019] Among them, sodium dithionite has a strong reducing property, and sodium dithionite (Na2S2O4) is extremely unstable. Na2S2O4 is easily decomposed and caused to burn when mixed with lithium manganite during ball milling. Reduction ball milling can produce a high-temperature environment and pre-reduces the high-valence states in lithium manganite, thereby activating the activity of Mn in lithium manganite.

[0020] Sulfur roasting generates heat and can burn even in low oxygen concentrations. Sulfur is more active, burns faster, and has a higher calorific value than ordinary coal. By thoroughly mixing ball-milled activated lithium manganese oxide with a certain molar ratio of sulfur and then roasting it at high temperature, a high-temperature, reducing atmosphere can be instantly created, enabling the reduction of the lithium manganese oxide.

[0021] Among them, during the combustion process of sulfur, sulfur dioxide flue gas can be generated. After the generated sulfur dioxide is collected, it can be oxidized under the action of a catalyst, dissolved in water and generate sulfuric acid solution, and sulfuric acid can be prepared for sale at the same time.

[0022] Among them, manganese oxide is leached by mixing sulfuric acid and acetic acid, and -COOH is introduced by acetic acid. After it is fully dissolved, a water retaining agent is added, and NaOH is introduced to adjust the pH of the solution to induce solution hydrolysis. Ethanol is added for hydroxylation and converted into MnOOH. Manganese oxyhydroxy is an antioxidant with excellent performance. It can effectively alleviate the corrosion of organic matter during the oxidation process, thereby protecting the organic matter from excessive oxidation. It is beneficial to the subsequent preparation of LiMnO2.

[0023] The calcined product is mixed with potassium permanganate and calcined to add lithium. The Mn in the added potassium permanganate is 7+ It has a very strong polarization ability and can form metal ion clusters. It has a strong oxidizing ability and can oxidize reducing ligands. Heptavalent manganese loses all valence electrons and can strongly oxidize lithium manganate, activating manganese activity.

[0024] In one embodiment, when the lithium manganate pole pieces of the waste battery are leached with sulfuric acid solution, the liquid-solid ratio of the leaching is (3-5) mL:1 g, and the leaching temperature is 60-80°C.

[0025] In one embodiment, the molar ratio of lithium manganite to sodium dithionite is (2-4): 1. When the molar ratio of the two is within this range, it can effectively pre-reduce the high-valent states in lithium manganite and activate the Mn activity in lithium manganite.

[0026] In one embodiment, the molar ratio of lithium manganite to sulfur is (1-2):1, and the mixture and sulfur are evenly mixed and calcined at a temperature of 300-500° C. for 30-120 minutes.

[0027] In one embodiment, the carboxyl group-containing mixed acid solution includes a sulfuric acid solution and an acetic acid solution; the concentration of the sulfuric acid solution is 50 to 120 g / L, and the concentration of the acetic acid solution is 50 to 50 g / L;

[0028] The volume ratio of the sulfuric acid solution to the acetic acid solution is (2-3):1.

[0029] In one embodiment, the mass ratio of the manganese oxide, the carboxyl group-containing mixed acid solution, the water retaining agent, and the ethanol solution is 1:(2-3):(0.8-1.5):(0.5-2).

[0030] In one embodiment, the water-retaining agent includes at least one of polyacrylamide, sodium polyacrylate, and starch-grafted acrylate.

[0031] In one embodiment, the ethanol solution is a 10-30% ethanol solution.

[0032] In one embodiment, the sodium hydroxide solution is a 10-40% sodium hydroxide solution.

[0033] In one embodiment, the molar ratio of lithium manganite to lithium hydroxide is (1-2):1.

[0034] In one embodiment, the molar ratio of lithium manganite to potassium permanganate is (4.5-6):1.

[0035] Among them, the molar ratio of lithium manganite to potassium permanganate has a great influence on the effect. If the molar ratio is too large (greater than 6:1), the added Mn source will be insufficient. If the molar ratio is too small (less than 4.5:1), it will lead to excessive consumption of potassium permanganate. Therefore, the molar ratio is controlled in the range of (4.5-6):1 in this application.

[0036] In one embodiment, the calcination temperature of the mixed manganese oxyhydroxide and lithium hydroxide is 600-800° C. and the calcination time is 60-90 min.

[0037] In one embodiment, the calcination temperature of the calcined product after mixing with potassium permanganate is 800-1000° C., and the calcination time is 60-90 minutes.

[0038] In one embodiment, the concentration of the hydrochloric acid solution is 30-80 g / L, the liquid-solid ratio of the leaching is (3-5) mL:1 g, and the leaching temperature is 50-80°C.

[0039] In one embodiment, the following steps are further included:

[0040] Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain an aluminum sulfate solution;

[0041] Aluminum sulfate solution is added to potassium sulfide solution, and the pH is adjusted to 2-5 with sodium hydroxide solution for hydrolysis. Lithium chloride is then added, ball milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O.

[0042] In one embodiment, m is an integer of 2-4, and n is an integer of 2-5.

[0043] The invention introduces weak anion S into the aluminum foil of waste battery by leaching it with sulfuric acid solution and then alkalizing the aluminum solution with potassium sulfide. 2- Slowly regulate the hydrolysis to generate OH - , forming a weak alkaline environment, which is conducive to Al 3+ Homogeneous hydrolysis promotes the formation of uniformly morphological LiCl·mAl(OH)3·nH2O. Adding solid-phase LiCl allows lithium ions to enter the octahedral cavities within the aluminum hydroxide layer as bare ions and be adsorbed. To balance the charge, chloride ions enter the interlayers. The sieving effect and the differential hydration behavior of lithium ions and other ions are the primary factors behind the adsorbent's excellent lithium selectivity. Ball milling with lithium chloride activates the lithium bonds of the aluminum hydroxide, enhancing its lithium-binding capacity. This transformation results in the preparation of LiCl·mAl(OH)3·nH2O with excellent adsorption properties.

[0044] In one embodiment, when the aluminum foil of the waste battery is leached with sulfuric acid solution, the concentration of the sulfuric acid solution is 50-100 g / L, the liquid-solid ratio of the leaching is (1-2) mL:1 g, and the leaching temperature is 60-70°C.

[0045] In one embodiment, the mass concentration of the potassium sulfide solution is 10-20 g / L.

[0046] In one embodiment, the molar ratio of the lithium chloride to the aluminum sulfate in the aluminum sulfate solution is 1:(1-2).

[0047] The beneficial effects of the present application are as follows: (1) The present application obtains Li4Mn5O by leaching the lithium manganese oxide electrode of waste battery with sulfuric acid, ball milling with sodium dithionite, sulfur roasting, water soaking, dissolving with carboxyl mixed acid solution, using water retaining agent and ethanol solution, adjusting pH to 3-4.5 with sodium hydroxide solution, achieving hydroxylation conversion, mixing with lithium hydroxide, and then roasting with potassium permanganate to obtain Li4Mn5O 12 , and then through hydrochloric acid leaching, a lithium ion sieve H4Mn5O with excellent adsorption performance was obtained. 12 (2) This application introduces weak anion S by leaching the aluminum foil of waste batteries with sulfuric acid solution and then alkalizing the aluminum solution with potassium sulfide. 2- Slowly regulate the hydrolysis to generate OH - , forming a weak alkaline environment, which is conducive to Al 3+ Homogeneous hydrolysis promotes the formation of uniformly morphological LiCl·mAl(OH)3·nH2O. Adding solid-phase LiCl allows lithium ions to enter the octahedral cavities within the aluminum hydroxide layer as bare ions and be adsorbed. To balance the charge, chloride ions enter the interlayers. The sieving effect and the differential hydration behavior of lithium ions and other ions are the primary factors behind the adsorbent's excellent lithium selectivity. Ball milling with lithium chloride activates the lithium bonds of the aluminum hydroxide, enhancing its lithium-binding capacity. This transformation results in the preparation of LiCl·mAl(OH)3·nH2O with excellent adsorption properties. BRIEF DESCRIPTION OF THE DRAWINGS

[0048] FIG1 is a flow chart of the present application.

[0049] Figure 2 shows the lithium ion sieve H4Mn5O prepared in Example 1 12 Electron microscope image of .

[0050] FIG3 is an electron microscope image of LiCl·mAl(OH)3·nH2O prepared in Example 1. DETAILED DESCRIPTION

[0051] To make the objectives, technical solutions, and advantages of the embodiments herein more clear, the technical solutions in the embodiments herein are described clearly and completely below. Obviously, the described embodiments are only a portion of the embodiments herein, not all of them. All other embodiments derived by persons of ordinary skill in the art based on the embodiments herein without inventive effort are also within the scope of protection herein.

[0052] Unless otherwise specified, the experimental reagents and instruments involved in the implementation of this article are commonly used reagents and instruments.

[0053] In this article, the technical features described in an open manner include closed technical solutions composed of the listed features, and also include open technical solutions containing the listed features.

[0054] As used herein, when referring to numerical ranges, unless otherwise specified, the numerical ranges are considered continuous and include the minimum and maximum values ​​of the range, as well as every value between such minimum and maximum values. Furthermore, when a range refers to an integer, every integer between the minimum and maximum values ​​of the range is included. In addition, when multiple ranges are provided to describe a feature or characteristic, the ranges may be combined. In other words, unless otherwise specified, all ranges disclosed herein should be understood to include any and all subranges subsumed therein.

[0055] Example 1

[0056] A method for recycling waste batteries, referring to FIG1 , comprises the following steps:

[0057] (1) The lithium manganate electrode of the waste battery is subjected to secondary leaching with 50 g / L dilute sulfuric acid to obtain lithium manganite;

[0058] The liquid-to-solid ratio during each leaching was 3 mL:1 g, and the leaching temperature was 60 °C;

[0059] (2) mixing strongly oxidizing sodium dithionite and lithium manganite in a molar ratio of 1:2 with ball milling to obtain a mixture;

[0060] (3) The mixture and sulfur were mixed and placed in a stainless steel sealed can, and then calcined in a muffle furnace at 300°C for 2 h. The calcined product was leached with water (the solid-liquid ratio of the calcined product to water was 1 g:3 mL) and dried to obtain manganese oxide;

[0061] Wherein, the molar ratio of sulfur to the lithium manganite in step (2) is 1:1.

[0062] (4) 60 g / L sulfuric acid solution and 50 g / L acetic acid solution were mixed uniformly in a volume ratio of 2:1 to obtain a carboxyl-containing mixed acid solution;

[0063] Manganese oxide is added to a carboxyl-containing mixed acid solution, and after complete dissolution, a water retaining agent and a 5% ethanol solution are added, and the pH is adjusted to 3 with a 15% sodium hydroxide solution, filtered, and dried to obtain manganese oxyhydroxide;

[0064] The mass ratio of manganese oxide, carboxyl mixed acid solution, water retaining agent (polyacrylamide), and ethanol solution is 1:2:0.8:0.5;

[0065] (5) Mixing manganese oxyhydroxide and lithium hydroxide evenly and calcining at 600°C for 1.5 hours;

[0066] Wherein, the molar ratio of lithium manganite to lithium hydroxide in step (2) is 1:1;

[0067] (6) The calcined product of step (5) was mixed with potassium permanganate and calcined at 800°C for 70 min to obtain Li4Mn5O 12 ;

[0068] Wherein, the molar ratio of lithium manganite to potassium permanganate in step (2) is 4.5:1.

[0069] (7) Li4Mn5O 12 Leaching with hydrochloric acid solution to obtain lithium ion sieve H4Mn5O 12 ;

[0070] The concentration of the hydrochloric acid solution is 40 g / L, the liquid-to-solid ratio of the leaching is 4 mL:1 g, and the leaching temperature is 60°C.

[0071] (8) Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain aluminum sulfate;

[0072] The concentration of the sulfuric acid solution is 50 g / L, the liquid-to-solid ratio of the leaching is 2 mL:1 g, and the leaching temperature is 60°C.

[0073] (9) Aluminum sulfate is added to a potassium sulfide solution, and the pH is adjusted to 3 with a 15% sodium hydroxide solution for hydrolysis. Lithium chloride is then added, and the mixture is ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O, where m is 2 and n is 2.

[0074] The mass concentration of the potassium sulfide solution is 10 g / L, and the solid-liquid ratio of aluminum sulfate to potassium sulfide solution is 1 g: 2 mL.

[0075] The molar ratio of lithium chloride to aluminum sulfate in the aluminum sulfate solution is 1:1.3.

[0076] The lithium ion sieve H4Mn5O prepared in this example 12 The electron microscope image of is shown in FIG1 , and the electron microscope image of LiCl·mAl(OH)3·nH2O prepared in this example is shown in FIG2 .

[0077] Example 2

[0078] A method for recycling waste batteries comprises the following steps:

[0079] (1) The lithium manganate electrode of the waste battery is subjected to secondary leaching with 80 g / L dilute sulfuric acid to obtain lithium manganite;

[0080] The liquid-to-solid ratio during each leaching was 4 mL:1 g, and the leaching temperature was 70 °C;

[0081] (2) mixing strongly oxidizing sodium dithionite and lithium manganite in a molar ratio of 1:2 with ball milling to obtain a mixture;

[0082] (3) The mixture and sulfur are mixed and placed in a stainless steel sealed can, and then placed in a muffle furnace and roasted at 400° C. for 2 h. The roasted product is leached with water and dried to obtain manganese oxide;

[0083] Wherein, the molar ratio of sulfur to the lithium manganite in step (2) is 1:1.5.

[0084] (4) 80 g / L sulfuric acid solution and 60 g / L acetic acid solution were mixed uniformly in a volume ratio of 2:1 to obtain a carboxyl group-containing mixed acid solution;

[0085] Manganese oxide is added to a carboxyl-containing mixed acid solution, and after complete dissolution, a water retaining agent (ammonium polyacrylate) and a 5% ethanol solution are added, and the pH is adjusted to 4 with a 15% sodium hydroxide solution, filtered, and dried to obtain manganese oxyhydroxide;

[0086] The mass ratio of manganese oxide, carboxyl mixed acid solution, water retaining agent and ethanol solution is 1:3:1.5:2.

[0087] (5) Mixing manganese oxyhydroxide and lithium hydroxide evenly and calcining at 600°C for 1.5 hours;

[0088] Wherein, the molar ratio of lithium hydroxide to lithium manganite is 1:2;

[0089] (6) The calcined product of step (5) was mixed with potassium permanganate and calcined at 800°C for 80 min to obtain Li4Mn5O 12 ;

[0090] Wherein, the molar ratio of lithium manganite to potassium permanganate in step (2) is 5:1.

[0091] (7) Li4Mn5O 12 Leaching with hydrochloric acid solution to obtain lithium ion sieve H4Mn5O 12 ;

[0092] The concentration of the hydrochloric acid solution is 40 g / L, the liquid-to-solid ratio of the leaching is 4 mL:1 g, and the leaching temperature is 60°C.

[0093] (8) Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain aluminum sulfate;

[0094] The concentration of the sulfuric acid solution is 50 g / L, the liquid-to-solid ratio of the leaching is 2 mL:1 g, and the leaching temperature is 60°C.

[0095] (9) Aluminum sulfate is added to a potassium sulfide solution, and the pH is adjusted to 3.5 with a 15% sodium hydroxide solution for hydrolysis. Lithium chloride is then added, and the mixture is ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O, where m is 2 and n is 2.

[0096] The mass concentration of the potassium sulfide solution is 15 g / L, and the material-liquid ratio of aluminum sulfate to potassium sulfide solution is 1:5 mL.

[0097] The molar ratio of lithium chloride to aluminum sulfate in the aluminum sulfate solution is 1:1.3.

[0098] Example 3

[0099] A method for recycling waste batteries comprises the following steps:

[0100] (1) The lithium manganate electrode of the waste battery is subjected to secondary leaching with 100 g / L dilute sulfuric acid to obtain lithium manganite;

[0101] The liquid-to-solid ratio during each leaching was 5 mL:1 g, and the leaching temperature was 70 °C;

[0102] (2) mixing strongly oxidizing sodium dithionite and lithium manganite in a molar ratio of 1:4 with ball milling to obtain a mixture;

[0103] (3) The mixture and sulfur are mixed and placed in a stainless steel sealed can, and then placed in a muffle furnace and roasted at 500° C. for 2 h. The roasted product is leached with water and dried to obtain manganese oxide;

[0104] Wherein, the molar ratio of sulfur to the lithium manganite in step (2) is 1:2.

[0105] (4) 120 g / L sulfuric acid solution and 80 g / L acetic acid solution were mixed uniformly in a volume ratio of 2:1 to obtain a carboxyl-containing mixed acid solution;

[0106] Adding manganese oxide to a carboxyl-containing mixed acid solution, and after complete dissolution, adding a water retaining agent and a 5% ethanol solution, adjusting the pH to 4 with a 15% sodium hydroxide solution, filtering, and drying to obtain manganese oxyhydroxide;

[0107] Among them, the dosage ratio of manganese oxide, carboxyl mixed acid solution, water retaining agent and ethanol solution is 1:2.5:1.2:1.5:1

[0108] (5) Mixing manganese oxyhydroxide and lithium hydroxide uniformly, and calcining at ℃ for h;

[0109] Wherein, the molar ratio of lithium hydroxide to lithium manganite is 1:1.5;

[0110] (6) The calcined product of step (5) was mixed with potassium permanganate and calcined at 800°C for 90 min to obtain Li4Mn5O 12 ;

[0111] Wherein, the molar ratio of lithium manganite to potassium permanganate in step (2) is 6:1.

[0112] (7) Li4Mn5O 12 Leaching with hydrochloric acid solution to obtain lithium ion sieve H4Mn5O 12 ;

[0113] The concentration of the hydrochloric acid solution is 40 g / L, the liquid-to-solid ratio of the leaching is 4 mL:1 g, and the leaching temperature is 60°C.

[0114] (8) Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain aluminum sulfate;

[0115] The concentration of the sulfuric acid solution is 50 g / L, the liquid-to-solid ratio of the leaching is 2 mL:1 g, and the leaching temperature is 60°C.

[0116] (9) Aluminum sulfate is added to a potassium sulfide solution, and the pH is adjusted to 3.5 with a 15% sodium hydroxide solution for hydrolysis. Lithium chloride is then added, and the mixture is ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O, where m is 2 and n is 2.

[0117] The mass concentration of the potassium sulfide solution is 20 g / L, and the material-liquid ratio of aluminum sulfate to potassium sulfide solution is 1:2 mL.

[0118] The molar ratio of lithium chloride to aluminum sulfate in the aluminum sulfate solution is 1:1.3.

[0119] Comparative Example 1

[0120] The difference between Comparative Example 1 and Example 1 is that Comparative Example 1 does not undergo the treatment of step (2) of Example 1, and the other aspects are the same.

[0121] A method for recycling waste batteries comprises the following steps:

[0122] (1) The lithium manganate electrode of the waste battery is subjected to secondary leaching with 50 g / L dilute sulfuric acid to obtain lithium manganite;

[0123] The liquid-to-solid ratio during each leaching was 3 mL:1 g, and the leaching temperature was 60 °C;

[0124] (2) lithium manganite and sulfur were mixed and placed in a stainless steel sealed can, and then calcined in a muffle furnace at 300°C for 2 h. The calcined product was leached with water (the solid-liquid ratio of the calcined product to water was 1 g:3 mL) and dried;

[0125] Wherein, the molar ratio of sulfur to lithium manganite is 1:1.

[0126] (3) 60 g / L sulfuric acid solution and 50 g / L acetic acid solution were mixed uniformly in a volume ratio of 2:1 to obtain a carboxyl-containing mixed acid solution;

[0127] The dried product of step (2) is added to the carboxyl mixed acid solution, and after complete dissolution, a water retaining agent and a 5% ethanol solution are added, and the pH is adjusted to 3 with a 15% sodium hydroxide solution, filtered, and dried;

[0128] The mass ratio of the dried product of step (2), the carboxyl-containing mixed acid solution, the water-retaining agent (polyacrylamide), and the ethanol solution is 1:2:0.8:0.5;

[0129] (4) mixing the product of step (3) with lithium hydroxide and calcining at 600° C. for 1.5 h;

[0130] Wherein, the molar ratio of lithium manganite to lithium hydroxide in step (2) is 1:1;

[0131] (5) mixing the calcined product of step (4) with potassium permanganate and calcining the mixture at 800° C. for 70 min;

[0132] Wherein, the molar ratio of lithium manganite to potassium permanganate in step (2) is 4.5:1.

[0133] (6) Leaching the dried product of step (5) with a hydrochloric acid solution to obtain comparative adsorbent-1;

[0134] The concentration of the hydrochloric acid solution is 40 g / L, the liquid-to-solid ratio of the leaching is 4 mL:1 g, and the leaching temperature is 60°C.

[0135] (7) Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain aluminum sulfate;

[0136] The concentration of the sulfuric acid solution is 50 g / L, the liquid-to-solid ratio of the leaching is 2 mL:1 g, and the leaching temperature is 60°C.

[0137] (8) Aluminum sulfate is added to a potassium sulfide solution, and the pH is adjusted to 3 with a 15% sodium hydroxide solution for hydrolysis. Lithium chloride is then added, and the mixture is ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O, where m is 2 and n is 2.

[0138] The mass concentration of the potassium sulfide solution is 10 g / L, and the solid-liquid ratio of aluminum sulfate to potassium sulfide solution is 1 g:2 mL.

[0139] The molar ratio of lithium chloride to aluminum sulfate in the aluminum sulfate solution is 1:1.3.

[0140] Comparative Example 2

[0141] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 does not undergo the treatment of step (4) of Example 1, and the other aspects are the same.

[0142] A method for recycling waste batteries, referring to FIG1 , comprises the following steps:

[0143] (1) The lithium manganate electrode of the waste battery is subjected to secondary leaching with 50 g / L dilute sulfuric acid to obtain lithium manganite;

[0144] The liquid-to-solid ratio during each leaching was 3 mL:1 g, and the leaching temperature was 60 °C;

[0145] (2) mixing strongly oxidizing sodium dithionite and lithium manganite in a molar ratio of 1:2 with ball milling to obtain a mixture;

[0146] (3) The mixture and sulfur were mixed and placed in a stainless steel sealed can, and then calcined in a muffle furnace at 300°C for 2 h. The calcined product was leached with water (the solid-liquid ratio of the calcined product to water was 1 g:3 mL) and dried to obtain manganese oxide;

[0147] Wherein, the molar ratio of sulfur to the lithium manganite in step (2) is 1:1.

[0148] (4) mixing manganese oxide and lithium hydroxide uniformly and calcining at 600°C for 1.5 hours;

[0149] Wherein, the molar ratio of lithium manganite to lithium hydroxide in step (2) is 1:1;

[0150] (5) mixing the calcined product of step (4) with potassium permanganate and calcining the mixture at 800° C. for 70 min;

[0151] Wherein, the molar ratio of lithium manganite to potassium permanganate in step (2) is 4.5:1.

[0152] (6) Leaching the dried product of step (5) with a hydrochloric acid solution to obtain comparative adsorbent-2;

[0153] The concentration of the hydrochloric acid solution is 40 g / L, the liquid-to-solid ratio of the leaching is 4 mL:1 g, and the leaching temperature is 60°C.

[0154] (7) Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain aluminum sulfate;

[0155] The concentration of the sulfuric acid solution is 50 g / L, the liquid-to-solid ratio of the leaching is 2 mL:1 g, and the leaching temperature is 60°C.

[0156] (8) Aluminum sulfate is added to a potassium sulfide solution, and the pH is adjusted to 3 with a 15% sodium hydroxide solution for hydrolysis. Lithium chloride is then added, and the mixture is ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O, where m is 2 and n is 2.

[0157] The mass concentration of the potassium sulfide solution is 10 g / L, and the solid-liquid ratio of aluminum sulfate to potassium sulfide solution is 1 g:2 mL.

[0158] The molar ratio of lithium chloride to aluminum sulfate in the aluminum sulfate solution is 1:1.3.

[0159] Comparative Example 3

[0160] The difference between Comparative Example 3 and Example 1 is that potassium dichromate is used instead of potassium permanganate in Comparative Example 3, and all other conditions are the same.

[0161] Comparative Example 4

[0162] The difference between Comparative Example 4 and Example 1 is that the molar ratio of lithium manganite to potassium permanganate in step (2) of Comparative Example 4 is 3:1, and the other steps are the same.

[0163] Comparative Example 5

[0164] The difference between Comparative Example 5 and Example 1 is that the molar ratio of lithium manganite to potassium permanganate in step (2) of Comparative Example 4 is 7:1, and the other aspects are the same.

[0165] Test Case

[0166] 1. 10g of lithium ion sieve H4Mn5O prepared in Examples 1 to 3 and Comparative Examples 3 to 5 12 The comparative adsorbents prepared in Comparative Examples 1 and 2 were placed in 200 mg / L lithium chloride solution, respectively, at 35° C., and kept warm for 24 hours. The adsorption capacity of the manganese-based lithium ion sieve was measured. The test results are shown in Table 1.

[0167] Table 1

[0168] 2. The LiCl·mAl(OH)3·nH2O prepared in Examples 1 to 3 were placed in 200 mg / L lithium chloride solution and kept warm at 35°C for 24 h. The adsorption capacity of LiCl·mAl(OH)3·nH2O was measured. The test results are shown in Table 2.

[0169] Table 2

[0170] Finally, it should be noted that the above embodiments are only used to illustrate the technical solutions of the present application and are not intended to limit the scope of protection of the present application. Although the present application has been described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application may be modified or replaced by equivalents without departing from the essence and scope of the technical solutions of the present application.

Claims

1. A method for recycling waste batteries, characterized in that: The following steps are involved: The lithium manganate pole pieces of the waste battery are leached with sulfuric acid solution to obtain lithium manganite; The lithium manganite and the sodium dithionite are ball-milled and mixed uniformly to obtain a mixture; The mixed material is uniformly mixed with sulfur, roasted, and the roasted product is soaked in water and dried to obtain manganese oxide; Adding manganese oxide to a carboxyl-containing mixed acid solution, adding a water retaining agent and an ethanol solution after the solution is completely dissolved, adding a sodium hydroxide solution to adjust the pH to 3-4.5, filtering, and drying to obtain manganese oxide hydroxide; Mixing manganese oxyhydroxide and lithium hydroxide evenly and calcining; The calcined product is mixed evenly with potassium permanganate and calcined to obtain Li4Mn5O 12 ; Li4Mn5O 12 Leaching with hydrochloric acid solution to obtain lithium ion sieve H4Mn5O 12 .

2. The method for recycling waste batteries according to claim 1, characterized in that: When the lithium manganese oxide pole pieces of the waste battery are leached with sulfuric acid solution, the liquid-to-solid ratio of the leaching is (3-5) mL:1 g, and the leaching temperature is 60-80°C.

3. The method for recycling waste batteries according to claim 1, characterized in that: The molar ratio of the lithium manganite to the sodium dithionite is (2-4):

1.

4. The method for recycling waste batteries according to claim 1, characterized in that: The molar ratio of lithium manganite to sulfur is (1-2):1, and the temperature of the calcination after the mixture and sulfur are evenly mixed is 300-500°C and the time is 30-120 minutes.

5. The method for recycling waste batteries according to claim 1, characterized in that: The carboxyl-containing mixed acid solution includes a sulfuric acid solution and an acetic acid solution; the concentration of the sulfuric acid solution is 50 to 120 g / L, and the concentration of the acetic acid solution is 50 to 50 g / L; The volume ratio of the sulfuric acid solution to the acetic acid solution is (2-3):

1.

6. The method for recycling waste batteries according to claim 1, characterized in that: The mass ratio of the manganese oxide, the carboxyl-containing mixed acid solution, the water retaining agent and the ethanol solution is 1:(2-3):(0.8-1.5):(0.5-2).

7. The method for recycling waste batteries according to claim 1, characterized in that: The molar ratio of the lithium manganite to the lithium hydroxide is (1-2):

1.

8. The method for recycling waste batteries according to claim 1, characterized in that: The molar ratio of the lithium manganite to the potassium permanganate is (4.5-6):

1.

9. The method for recycling waste batteries according to claim 1, characterized in that: The calcination temperature of the mixed manganese oxyhydroxide and lithium hydroxide is 600-800°C, and the calcination time is 90-120 minutes; The roasting temperature of the roasted product after mixing with potassium permanganate is 800-1000°C, and the roasting time is 60-90 minutes.

10. The method for recycling waste batteries according to claim 1, characterized in that: The concentration of the hydrochloric acid solution is 30-80 g / L, the liquid-to-solid ratio of the leaching is (3-5) mL:1 g, and the leaching temperature is 50-80° C.

11. The method for recycling waste batteries according to claim 1, characterized in that: The following steps are also included: Leaching the aluminum foil of the waste battery with a sulfuric acid solution to obtain an aluminum sulfate solution; The aluminum sulfate solution is added to the potassium sulfide solution, and the pH is adjusted to 2-5 with a sodium hydroxide solution for hydrolysis, and then lithium chloride is added, ball-milled, filtered, and dried to obtain LiCl·mAl(OH)3·nH2O; Here, m is an integer of 2-4, and n is an integer of 2-5.

12. The method for recycling waste batteries according to claim 11, characterized in that: The concentration of the sulfuric acid solution is 50-100 g / L.

13. The method for recycling waste batteries according to claim 11, characterized in that: When the aluminum foil of waste batteries is leached with sulfuric acid solution, the liquid-to-solid ratio is (1-2) mL:1 g, and the leaching temperature is ~℃.

14. The method for recycling waste batteries according to claim 11, characterized in that: The mass concentration of the potassium sulfide solution is 10-20 g / L.

15. The method for recycling waste batteries according to claim 11, characterized in that: The molar ratio of the lithium chloride to the aluminum sulfate in the aluminum sulfate solution is 1:(1-2).

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