A recycling method for lithium manganate batteries

Abstract

The invention provides a recycling method for lithium manganate batteries, which belongs to the field of batteries. The method comprises: crushing the lithium manganate ion battery and then heating it for reaction, collecting the condensed electrolyte by negative pressure to obtain a solid material, and then roasting it; leaching with water and filtering to obtain a lithium solution and a slag containing manganese, copper, iron, aluminum and graphite; removing impurities from the obtained lithium solution and filtering to obtain a pure lithium hydroxide solution, and concentrating and crystallizing the lithium hydroxide to obtain a battery-grade lithium hydroxide product; adding water to the slag containing manganese, copper, iron, aluminum and graphite to prepare a pulp, and then adding acid for adjustment; adding reduced iron powder to the solution to remove copper; adding sodium chlorate to the obtained solution to oxidize divalent iron in the raffinate to trivalent iron, and then adjusting the extracted raffinate with alkali solution, and filtering to obtain slag containing iron and lithium and a manganese solution containing calcium and magnesium; extracting manganese in the manganese solution with a C272 extractant, and obtaining a manganese sulfate or manganese chloride solution after back extraction, and concentrating and crystallizing to obtain a battery-grade manganese sulfate or manganese chloride for batteries.

Description

Technical Field

[0001] The invention belongs to the field of battery manufacturing, and in particular relates to a recycling method for lithium manganate batteries. Background Art

[0002] Lithium manganese oxide battery refers to a battery whose positive electrode uses lithium manganese oxide material. The nominal voltage of lithium manganese oxide battery is 2.5~4.2V. Lithium manganese oxide battery is widely used due to its low cost and good safety.

[0003] However, lithium-ion manganese oxide batteries typically have a lifespan of 1-3 years. Used lithium-ion batteries contain a variety of hazardous substances, such as organic solvents, heavy metals, and toxic gases. If not recycled, they can cause serious environmental pollution. The most valuable aspect of recycling used lithium-ion batteries is the recovery of metals such as manganese, copper, lithium, iron, and aluminum. Current technologies are capable of recovering these metals, but the complex cathode materials used in existing lithium-ion manganese oxide batteries complicate and complicate the subsequent separation and purification process, resulting in a low-purity lithium product. Summary of the Invention

[0004] The present invention provides a method for recovering lithium manganese oxide batteries. This method utilizes the reducing properties of the iron and aluminum in the battery after being ground into powder, as well as the reducing properties of graphite produced by combustion under certain conditions, to reduce the positive electrode material of the lithium manganese oxide battery during the calcination process, allowing the lithium to be selectively leached out at the front end using water. This process achieves a lithium leaching rate of up to 98.5%, while eliminating the need for the addition of reducing gases such as hydrogen. The slag containing manganese, copper, iron, aluminum, and graphite is adjusted to a pH of 1.0-2.0 using sulfuric acid or hydrochloric acid. The manganese leaching rate can reach 99.5%, while the leaching rates of copper, iron, and aluminum are less than 10%. This method effectively separates manganese from copper, iron, and aluminum. Manganese is extracted from the manganese solution using a C272 extractant. The resulting manganese sulfate or manganese chloride, obtained after stripping, does not require impurity removal and can be directly concentrated and crystallized to produce battery-grade manganese sulfate or battery-grade manganese chloride.

[0005] The present invention is achieved through the following technical solution: a method for recycling lithium manganese oxide batteries, comprising the following steps:

[0006] Step 1: crushing the lithium manganate battery in an inert protective atmosphere to obtain crushed materials;

[0007] Step 2: placing the crushed material in a closed environment for heating and reaction, and collecting the condensed electrolyte by negative pressure to obtain a solid material;

[0008] Step 3: After ball milling, the solid material is passed through a 20-500 mesh sieve;

[0009] Step 4: The solid material of step 3 is subjected to first-stage roasting and second-stage roasting;

[0010] Step 5: Leaching with water and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite;

[0011] Step 6: The lithium solution obtained in step 5 is purified by resin or membrane to obtain a pure lithium hydroxide solution, and the lithium hydroxide is concentrated and crystallized to obtain a battery-grade lithium hydroxide monohydrate product;

[0012] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to make a slurry, then add sulfuric acid or hydrochloric acid to adjust the pH value to be stable at 1.0-2.0 for 20-40 minutes, and filter to obtain graphite and solution.

[0013] Step 8: Add reduced iron powder to the solution in step 7 to remove copper, and filter to obtain sponge copper and copper-removed liquid;

[0014] Step 9: adding sodium chlorate to the copper-removed solution obtained in step 8 to oxidize the divalent iron in the raffinate to trivalent iron, then adjusting the pH of the raffinate to 4.0-5.0 with sodium hydroxide, sodium carbonate or calcium carbonate, and filtering the iron-lithium-containing slag and the calcium-magnesium-containing manganese solution;

[0015] Step 10: extracting manganese from the manganese solution with C272 extractant, stripping to obtain manganese sulfate or manganese chloride solution, concentrating and crystallizing to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0016] The main component of the C272 extractant is di(2,4,4-trimethylpentyl)phosphonic acid. Typical physical properties of industrial products: content >85%; colorless or slightly amber; density (24°C) 0.92 g / cm 3 , viscosity (25℃) 0.142Pa.s, (50℃) 0.037Pa.s; freezing point -32℃; flash point 108℃; solubility in water (PH=2.6) is 16ppm.

[0017] Preferably, in step 2, the reaction temperature is 100-250°C.

[0018] Preferably, in step 4, the first stage of calcination is carried out at 300-400° C. for 1-3 h in an inert protective atmosphere, and the second stage of calcination is carried out at 750-1000° C. for 20-60 min in an air atmosphere.

[0019] Preferably, in step 7, the slag containing manganese, copper, iron, aluminum and graphite is slurried with water, and the solid-liquid ratio is 1:3-1:6.

[0020] Preferably, in step 8, reduced iron powder is added to the solution, and the amount of iron powder added is 1.0-1.3 times the total amount of copper in the solution, and the copper content in the solution after copper removal is no more than 0.005 g / L.

[0021] The present invention has the following beneficial effects:

[0022] 1. The present invention utilizes the reducing properties of the iron and aluminum in the battery itself after being ground into powder, and the reducing properties of graphite produced by combustion under certain conditions to produce carbon monoxide. During the roasting process, the positive electrode material of the lithium manganese oxide battery is reduced, so that lithium can be selectively leached with water at the front end. This process has a lithium leaching rate of up to 98.5%, and no external reducing gases such as hydrogen are required.

[0023] 2. The slag containing manganese, copper, iron, aluminum and graphite is adjusted to pH 1.0-2.0 with sulfuric acid or hydrochloric acid. The leaching rate of manganese can reach 99.5%, while the leaching rate of copper, iron and aluminum is less than 10%. This method effectively separates manganese from copper, iron and aluminum.

[0024] 3. Use C272 extractant to extract manganese from the manganese solution. The manganese sulfate or manganese chloride obtained after stripping does not need to be removed from the impurities. It can be directly concentrated and crystallized to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0025] 4. The lithium hydroxide solution obtained after reduction can be used to prepare battery-grade lithium hydroxide monohydrate after removing impurities through resin or membrane. DETAILED DESCRIPTION

[0026] The following detailed description of the present application will make the features and advantages of the present application clearer and more explicit.

[0027] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "front," "back," "left," and "right" and the like indicate positions or locations based on the operating state of this application. These terms are intended only to facilitate the description of this application and simplify the description. They are not intended to indicate or imply that the devices or components referred to must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on this application. Furthermore, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0028] The following will be combined with the embodiments of the present application to clearly and completely describe the technical solutions in the embodiments of the present application. Obviously, the embodiments described are only part of the embodiments of the present application, not all of the embodiments. Based on the embodiments of the present application, all other embodiments obtained by those skilled in the art without making creative efforts shall fall within the scope of protection of this application.

[0029] Example 1, a method for recycling lithium manganese oxide batteries, comprising the following steps:

[0030] Step 1: crushing the lithium manganate ion battery in an inert protective atmosphere to obtain crushed materials;

[0031] Step 2: The crushed material is placed in a closed environment for heating reaction, and the condensed electrolyte is collected by negative pressure to obtain a solid material. The reaction temperature is 100°C;

[0032] Step 3: After ball milling, the solid material is passed through a 500-mesh sieve;

[0033] Step 4: calcining at 300°C for 3 hours in an inert atmosphere, and then calcining at 750°C for 60 minutes in air.

[0034] Step 5: Leaching with water and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite;

[0035] Step 6: The lithium solution obtained in step 5 is purified by resin or membrane to obtain a pure lithium hydroxide solution, and the lithium hydroxide is concentrated and crystallized to obtain a battery-grade lithium hydroxide monohydrate product.

[0036] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to prepare a slurry with a solid-liquid ratio of 1:3, add sulfuric acid or hydrochloric acid, adjust the pH value to be stable at 2.0 for 40 minutes, and filter to obtain graphite and solution.

[0037] Step 8: Adding reduced iron powder to the solution, wherein the amount of iron powder added is 1.0 times the total amount of copper in the solution, and the copper content in the copper-removed solution is not greater than 0.005 g / L, and filtering to obtain sponge copper and copper-removed solution;

[0038] Step 9: Sodium chlorate is added to the copper-removed solution obtained in step 8 to oxidize the divalent iron in the raffinate to trivalent iron, and then the pH value of the raffinate after extraction in step 9 is adjusted to 4.0 with sodium hydroxide, sodium carbonate or calcium carbonate, and the iron-lithium-containing slag and the calcium-magnesium-containing manganese solution are filtered.

[0039] Step 10: extracting manganese from the manganese solution with C272 extractant, stripping to obtain manganese sulfate or manganese chloride solution, concentrating and crystallizing to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0040] Example 2, a method for recycling lithium manganese oxide batteries, comprising the following steps:

[0041] Step 1: crushing the lithium manganate ion battery in an inert protective atmosphere to obtain crushed materials;

[0042] Step 2: The crushed material is placed in a closed environment for heating reaction, and the condensed electrolyte is collected by negative pressure to obtain a solid material. The reaction temperature is 250°C;

[0043] Step 3: After ball milling, the solid material is passed through a 20-mesh sieve;

[0044] Step 4: calcining at 400°C for 1 hour in an inert protective atmosphere, and then calcining at 1000°C for 20 minutes in an air atmosphere;

[0045] Step 5: Leaching with water and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite;

[0046] Step 6: The lithium solution obtained in step 5 is purified by resin or membrane to obtain a pure lithium hydroxide solution, and the lithium hydroxide is concentrated and crystallized to obtain a battery-grade lithium hydroxide monohydrate product.

[0047] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to prepare a slurry with a solid-liquid ratio of 1:6, add sulfuric acid or hydrochloric acid, adjust the pH value to be stable at 1.0 for 20 minutes, and filter to obtain graphite and solution.

[0048] Step 8: Adding reduced iron powder to the solution, wherein the amount of iron powder added is 1.3 times the total amount of copper in the solution, and the copper content in the copper-removed solution is not greater than 0.005 g / L, and filtering to obtain sponge copper and copper-removed solution;

[0049] Step 9: Sodium chlorate is added to the copper-removed solution obtained in step 8 to oxidize the divalent iron in the raffinate to trivalent iron, and then the pH value of the raffinate after extraction in step 9 is adjusted to 5.0 with sodium hydroxide, sodium carbonate or calcium carbonate, and the iron-lithium-containing slag and the calcium-magnesium-containing manganese solution are filtered.

[0050] Step 10: extracting manganese from the manganese solution with C272 extractant, stripping to obtain manganese sulfate or manganese chloride solution, concentrating and crystallizing to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0051] Example 3, a method for recycling lithium manganese oxide batteries, comprising the following steps:

[0052] Step 1: crushing the lithium manganate ion battery in an inert protective atmosphere to obtain crushed materials;

[0053] Step 2: The crushed material is placed in a closed environment for heating reaction, and the condensed electrolyte is collected by negative pressure to obtain a solid material. The reaction temperature is 200°C;

[0054] Step 3: After ball milling, the solid material is passed through a 500-mesh sieve;

[0055] Step 4: calcining at 350°C for 2 h in an inert atmosphere, and then calcining at 800°C for 40 min in air.

[0056] Step 5: Leaching with water and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite;

[0057] Step 6: The lithium solution obtained in step 5 is purified by resin or membrane to obtain a pure lithium hydroxide solution, and the lithium hydroxide is concentrated and crystallized to obtain a battery-grade lithium hydroxide monohydrate product.

[0058] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to prepare a slurry with a solid-liquid ratio of 1:4, add sulfuric acid or hydrochloric acid, adjust the pH value to be stable at 1.5 for 30 minutes, and filter to obtain graphite and solution.

[0059] Step 8: Adding reduced iron powder to the solution, wherein the amount of iron powder added is 1.2 times the total amount of copper in the solution, and the copper content in the copper-removed solution is not greater than 0.005 g / L, and filtering to obtain sponge copper and copper-removed solution;

[0060] Step 9: Sodium chlorate is added to the copper-removed solution obtained in step 8 to oxidize the divalent iron in the raffinate to trivalent iron, and then the pH value of the raffinate after extraction in step 9 is adjusted to 4.5 with sodium hydroxide, sodium carbonate or calcium carbonate, and the iron-lithium-containing slag and the calcium-magnesium-containing manganese solution are filtered.

[0061] Step 10: extracting manganese from the manganese solution with C272 extractant, stripping to obtain manganese sulfate or manganese chloride solution, concentrating and crystallizing to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0062] The present application has been described in detail above with reference to specific embodiments and exemplary examples. However, these descriptions should not be construed as limiting the present application. Those skilled in the art will appreciate that, without departing from the spirit and scope of the present application, various equivalent substitutions, modifications, or improvements may be made to the technical solutions and implementations of the present application, all of which fall within the scope of the present application. The scope of protection of the present application shall be determined by the appended claims.

Claims

1. A method for recycling lithium manganese oxide batteries, characterized in that: The following steps are involved: Step 1: crushing the lithium manganate ion battery in an inert protective atmosphere to obtain crushed materials; Step 2: placing the crushed material in a closed environment for heating and reaction, and collecting the condensed electrolyte by negative pressure to obtain a solid material; Step 3: After ball milling, the solid material is passed through a 20-500 mesh sieve; Step 4: The solid material of step 3 is subjected to first-stage roasting and second-stage roasting; Step 5: Leaching with water and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite; Step 6: The lithium solution obtained in step 5 is purified by resin or membrane to obtain a pure lithium hydroxide solution, and the lithium hydroxide is concentrated and crystallized to obtain a battery-grade lithium hydroxide monohydrate product; Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to make a slurry, then add sulfuric acid or hydrochloric acid to adjust the pH value to be stable at 1.0-2.0 for 20-40 minutes, and filter to obtain graphite and solution; Step 8: Add reduced iron powder to the solution in step 7 to remove copper, and filter to obtain sponge copper and copper-removed liquid; Step 9: adding sodium chlorate to the copper-removed solution obtained in step 8 to oxidize the divalent iron in the raffinate to trivalent iron, then adjusting the pH of the raffinate to 4.0-5.0 with sodium hydroxide, sodium carbonate or calcium carbonate, and filtering the iron-lithium-containing slag and the calcium-magnesium-containing manganese solution; Step 10: extracting manganese from the manganese solution with C272 extractant, stripping to obtain manganese sulfate or manganese chloride solution, concentrating and crystallizing to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

2. The method for recycling lithium manganate batteries according to claim 1, wherein: In step 2, the reaction temperature is 100-250°C.

3. The method for recycling lithium manganate batteries according to claim 1, wherein: In step 4, the first stage of calcination is carried out at a temperature of 300-400° C. for 1-3 hours in an inert protective atmosphere, and the second stage of calcination is carried out at a temperature of 750-1000° C. for 20-60 minutes in an air atmosphere.

4. The method for recycling lithium manganate batteries according to claim 1, wherein: In step 7, the slag containing manganese, copper, iron, aluminum and graphite is added with water to prepare slurry, and the solid-liquid ratio is 1:3-1:

6.

5. The method for recycling lithium manganate batteries according to claim 1, wherein: In step 8, reduced iron powder is added to the solution, and the amount of iron powder added is 1.0-1.3 times the total amount of copper in the solution. After copper removal, the copper content in the solution is not greater than 0.005 g / L.