Recycling method of lithium manganate battery

Abstract

The invention provides a lithium manganate battery recovery method, which belongs to the field of batteries, and comprises the following steps: crushing a lithium manganate ion battery to obtain a crushed material; heating the crushed material for reaction, and collecting electrolyte to obtain a solid material; carrying out ball milling on the solid material and sieving; roasting the sieved solid material; leaching the roasted material with water, and filtering to obtain a lithium solution and slag containing manganese, copper, iron, aluminum and graphite; and removing impurities from the obtained lithium solution by using resin or a film to obtain a pure lithium hydroxide solution, and concentrating and crystallizing lithium hydroxide to obtain a battery-grade lithium hydroxide monohydrate product. According to the method, the lithium can be selectively leached by water at the front end, the leaching rate of the lithium is as high as 98.5%, and meanwhile, additional reducing gases such as hydrogen and the like are not needed.

Description

[0001] This application is a divisional application of the invention patent with application number 202310136574.0, invention title "A method for recycling lithium manganese oxide batteries", and application date of February 20, 2023. Technical Field

[0002] This invention belongs to the field of battery manufacturing, and specifically relates to a method for recycling lithium manganese oxide batteries. Background Technology

[0003] Lithium manganese oxide batteries are batteries that use lithium manganese oxide material in the positive electrode. The nominal voltage of lithium manganese oxide batteries is between 2.5 and 4.2V. Lithium manganese oxide batteries are widely used because of their low cost and good safety.

[0004] However, the lifespan of lithium manganese oxide batteries is generally only 1-3 years. Used lithium-ion batteries contain various harmful substances, such as organic solvents, heavy metals, and toxic gases, which can cause serious environmental pollution if not recycled. The most valuable aspect of recycling used lithium-ion batteries lies in recovering metals such as manganese, copper, lithium, iron, and aluminum. Current technologies can recover these metals, but the complexity of the cathode materials in existing lithium manganese oxide batteries makes subsequent separation and purification processes complicated and difficult, resulting in low purity of the final lithium product. Summary of the Invention

[0005] The purpose of this invention is to provide a method for recycling lithium manganese oxide batteries. This invention utilizes the reducing properties of iron and aluminum in the battery itself after being ground into powder, and the reducing properties of carbon monoxide produced by the combustion of graphite under certain conditions. During the calcination process, the positive electrode material of the lithium manganese oxide battery is reduced, allowing lithium to be selectively leached with water at the front end. This process achieves a lithium leaching rate as high as 98.5%, without the need for external 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 rate of copper, iron, and aluminum is less than 10%. This method effectively separates manganese from copper, iron, and aluminum. Manganese in the manganese solution is extracted using C272 extractant. The resulting manganese sulfate or manganese chloride does not require impurity removal and can be directly concentrated and crystallized to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0006] This invention is achieved through the following technical solution: a method for recycling lithium manganese oxide batteries, comprising the following steps: Crushing: The lithium manganese oxide battery is crushed to obtain crushed material; Heating: The crushed material is heated to react, the electrolyte is collected, and a solid material is obtained; Ball milling and sieving: The solid material is ball-milled and then sieved. Calcination: The sieved solid material is subjected to a first-stage calcination and a second-stage calcination; Water leaching: After leaching the roasted material with water, the residue was filtered to obtain a lithium solution and a slag containing manganese, copper, iron, aluminum and graphite. Lithium hydroxide preparation: The obtained lithium solution is purified by removing impurities with resin or membrane to obtain a pure lithium hydroxide solution. The lithium hydroxide is then concentrated and crystallized to obtain battery-grade lithium hydroxide monohydrate product.

[0007] Preferably, the crushing is carried out in an inert protective atmosphere.

[0008] Preferably, the crushed material is heated and reacted in a closed environment, and the condensed electrolyte is collected by negative pressure.

[0009] Preferably, the heating reaction temperature is 100-250℃.

[0010] Preferably, the ball milling and sieving process involves passing the material through a 20-500 mesh sieve.

[0011] As a preferred method, the first stage of calcination is carried out at 300-400℃ for 1-3 hours in an inert protective atmosphere, followed by a second stage of calcination at 750-1000℃ for 20-60 minutes in an air atmosphere.

[0012] Preferably, the process also includes the following steps: acid leaching: the residue containing manganese, copper, iron, aluminum and graphite is mixed with water to make a slurry, and then acid is added to adjust the pH value to be stable at 1.0-2.0 for 20-40 minutes, and then filtered to obtain graphite and solution.

[0013] Preferably, the following steps are also included: Copper removal: Add reduced iron powder to the solution to remove copper, and filter to obtain sponge copper and copper-removed liquid; Separation: Add an oxidant to the solution after copper removal to oxidize the ferrous iron in the raffinate to ferric iron. Then, adjust the pH of the raffinate to 4.0-5.0 with sodium hydroxide, sodium carbonate or calcium carbonate. Filter to obtain slag containing lithium iron and a manganese solution containing calcium and magnesium. Extraction: Manganese in the manganese solution was extracted with C272 extractant, and the manganese salt solution was obtained after back-extraction. The solution was then concentrated and crystallized to obtain battery-grade manganese salt.

[0014] The main component of C272 extractant is bis(2,4,4-trimethylpentyl)phosphonic acid. Typical physical properties of the industrial product are: content >85%; colorless or slightly amber; density (24℃) 0.92 g / cm³; viscosity (25℃) 0.142 Pa·s, (50℃) 0.037 Pa·s; freezing point -32℃; flash point 108℃; solubility in water (pH = 2.6) 16 ppm.

[0015] Preferably, in the acid leaching step, the slag containing manganese, copper, iron, aluminum and graphite is mixed with water to form a slurry with a solid-liquid ratio of 1:3-1:6.

[0016] Preferably, in the copper removal step, the amount of reduced 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 not greater than 0.005 g / L.

[0017] Preferably, during the acid leaching step, an inorganic acid is added to adjust the pH value.

[0018] Preferably, the oxidant is sodium chlorate.

[0019] Preferably, the inorganic acid is hydrochloric acid or sulfuric acid.

[0020] Preferably, after back-extraction, a manganese sulfate or manganese chloride solution is obtained, which is then concentrated and crystallized to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0021] The present invention has the following beneficial effects: 1. This invention utilizes the reducing properties of iron and aluminum powder in the battery itself, as well as the reducing properties of carbon monoxide produced by the combustion of graphite under certain conditions. During the calcination process, the positive electrode material of lithium manganese oxide battery is reduced, so that lithium can be selectively leached out with water at the front end. This process has a lithium leaching rate of up to 98.5%, and at the same time, it does not require the addition of reducing gases such as hydrogen.

[0022] 2. When the pH value of slag containing manganese, copper, iron, aluminum and graphite is adjusted to 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.

[0023] 3. Extract manganese from the manganese solution using C272 extractant. The resulting manganese sulfate or manganese chloride does not need to be purified. It can be directly concentrated and crystallized to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0024] 4. The lithium hydroxide solution obtained after reduction can be purified by passing it through resin or membrane to prepare battery-grade lithium hydroxide monohydrate. Detailed Implementation

[0025] The features and advantages of this application will become clearer and more explicit through the following detailed description.

[0026] In the description of this application, it should be noted that the terms "upper," "lower," "inner," "outer," "front," "rear," "left," and "right," etc., indicate the orientation or positional relationship based on the orientation or positional relationship in the working state of this application, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation on this application. In addition, the terms "first," "second," "third," and "fourth" are used for descriptive purposes only and should not be construed as indicating or implying relative importance.

[0027] The technical solutions in the embodiments of this application will be clearly and completely described below with reference to the embodiments of this application. Obviously, the described embodiments are only some embodiments of this application, and not all embodiments. Based on the embodiments of this application, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of this application.

[0028] Example 1: A method for recycling lithium manganese oxide batteries, comprising the following steps: Step 1: The lithium manganese oxide battery is crushed in an inert protective atmosphere to obtain crushed material; Step 2: The crushed material is placed in a closed environment and heated to react. The condensed electrolyte is collected by negative pressure to obtain solid material. The reaction temperature is 100℃. Step 3: After ball milling, the solid material is passed through a 500-mesh sieve; Step 4: In an inert protective atmosphere, calcine at 300℃ for 3 hours in the first stage, and in an air atmosphere, calcine at 750℃ for 60 minutes in the second stage. Step 5: After leaching with water, filter to obtain lithium solution and residue containing manganese, copper, iron, aluminum and graphite; Step 6: The lithium solution obtained in Step 5 is purified by using resin or membrane to obtain a pure lithium hydroxide solution. The lithium hydroxide is then concentrated and crystallized to obtain battery-grade lithium hydroxide monohydrate product.

[0029] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to make a slurry with a solid-liquid ratio of 1:3. Add sulfuric acid or hydrochloric acid to adjust the pH value to be stable at 2.0 for 40 minutes. Filter to obtain graphite and solution.

[0030] Step 8: Add reduced iron powder to the solution. The amount of iron powder added is 1.0 times the total amount of copper in the solution. The copper content in the solution after copper removal is no more than 0.005 g / L. Filter to obtain sponge copper and copper-removed solution. Step 9: Add sodium chlorate to the copper-removed solution obtained in Step 8 to oxidize the ferrous iron in the raffinate to ferric iron. Then, adjust the pH of the raffinate after extraction in Step 9 to 4.0 using sodium hydroxide, sodium carbonate, or calcium carbonate. Filter out the lithium iron ore residue and the calcium and magnesium manganese solution.

[0031] Step 10: Extract manganese from the manganese solution using C272 extractant. After back-extraction, obtain manganese sulfate or manganese chloride solution. Concentrate and crystallize to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0032] Example 2, a method for recycling lithium manganese oxide batteries, includes the following steps: Step 1: The lithium manganese oxide battery is crushed in an inert protective atmosphere to obtain crushed material; Step 2: The crushed material is placed in a closed environment and heated to react. The condensed electrolyte is collected under negative pressure to obtain solid material. The reaction temperature is 250°C. Step 3: After ball milling, the solid material is passed through a 20-mesh sieve; Step 4: Calcination in an inert protective atmosphere at 400℃ for 1 hour, followed by calcination in an air atmosphere at 1000℃ for 20 minutes. Step 5: After leaching with water, filter to obtain lithium solution and residue containing manganese, copper, iron, aluminum and graphite; Step 6: The lithium solution obtained in Step 5 is purified by using resin or membrane to obtain a pure lithium hydroxide solution. The lithium hydroxide is then concentrated and crystallized to obtain battery-grade lithium hydroxide monohydrate product.

[0033] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to make a slurry with a solid-liquid ratio of 1:6. Add sulfuric acid or hydrochloric acid to adjust the pH value to be stable at 1.0 for 20 minutes. Filter to obtain graphite and solution.

[0034] Step 8: Add reduced iron powder to the solution. The amount of iron powder added is 1.3 times the total amount of copper in the solution. The copper content in the solution after copper removal is no more than 0.005 g / L. Filter to obtain sponge copper and copper-removed solution. Step 9: Add sodium chlorate to the copper-removed solution obtained in Step 8 to oxidize the ferrous iron in the raffinate to ferric iron. Then, adjust the pH of the raffinate after extraction in Step 9 to 5.0 with sodium hydroxide, sodium carbonate, or calcium carbonate. Filter out the lithium iron ore residue and the calcium and magnesium manganese solution.

[0035] Step 10: Extract manganese from the manganese solution using C272 extractant. After back-extraction, obtain manganese sulfate or manganese chloride solution. Concentrate and crystallize to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0036] Example 3: A method for recycling lithium manganese oxide batteries, comprising the following steps: Step 1: The lithium manganese oxide battery is crushed in an inert protective atmosphere to obtain crushed material; Step 2: The crushed material is placed in a closed environment and heated to react. The condensed electrolyte is collected by negative pressure to obtain solid material. The reaction temperature is 200℃. Step 3: After ball milling, the solid material is passed through a 500-mesh sieve; Step 4: Calcination in an inert protective atmosphere at 350℃ for 2 hours, followed by a second calcination in an air atmosphere at 800℃ for 40 minutes. Step 5: After leaching with water, filter to obtain lithium solution and residue containing manganese, copper, iron, aluminum and graphite; Step 6: The lithium solution obtained in Step 5 is purified by using resin or membrane to obtain a pure lithium hydroxide solution. The lithium hydroxide is then concentrated and crystallized to obtain battery-grade lithium hydroxide monohydrate product.

[0037] Step 7: Add water to the slag containing manganese, copper, iron, aluminum and graphite to make a slurry with a solid-liquid ratio of 1:4. Add sulfuric acid or hydrochloric acid to adjust the pH value to a stable 1.5 for 30 minutes. Filter to obtain graphite and solution.

[0038] Step 8: Add reduced iron powder to the solution. The amount of iron powder added is 1.2 times the total amount of copper in the solution. The copper content in the solution after copper removal is no more than 0.005 g / L. Filter to obtain sponge copper and copper-removed solution. Step 9: Add sodium chlorate to the copper-removed solution obtained in Step 8 to oxidize the ferrous iron in the raffinate to ferric iron. Then, adjust the pH of the raffinate after extraction in Step 9 to 4.5 with sodium hydroxide, sodium carbonate, or calcium carbonate. Filter out the lithium iron ore residue and the calcium and magnesium manganese solution.

[0039] Step 10: Extract manganese from the manganese solution using C272 extractant. After back-extraction, obtain manganese sulfate or manganese chloride solution. Concentrate and crystallize to obtain battery-grade manganese sulfate or battery-grade manganese chloride.

[0040] 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 understand that various equivalent substitutions, modifications, or improvements can be made to the technical solutions and implementation methods of the present application without departing from the spirit and scope of the present application, and all such modifications and improvements fall within the scope of the present application. The scope of protection of the present application is determined by the appended claims.

Claims

1. A method for recycling lithium manganese oxide batteries, characterized in that, Includes the following steps: Crushing: The lithium manganese oxide battery is crushed to obtain crushed material; Heating: The crushed material is heated to react, the electrolyte is collected, and a solid material is obtained; Ball milling and sieving: The solid material is ball-milled and then sieved. Calcination: The sieved solid material is subjected to a first-stage calcination and a second-stage calcination; Water leaching: After leaching the roasted material with water, the residue was filtered to obtain a lithium solution and a slag containing manganese, copper, iron, aluminum and graphite. Lithium hydroxide preparation: The obtained lithium solution is purified by removing impurities with resin or membrane to obtain a pure lithium hydroxide solution. The lithium hydroxide is then concentrated and crystallized to obtain battery-grade lithium hydroxide monohydrate product.

2. The method for recycling lithium manganese oxide batteries according to claim 1, characterized in that, The crushing was carried out in an inert protective atmosphere; And / or, the crushed material is placed in a closed environment for heating and reaction, and the condensed electrolyte is collected by negative pressure.

3. The method for recycling lithium manganese oxide batteries according to claim 1, characterized in that, The heating reaction temperature is 100-250℃; And / or, the ball milling is sieved through a 20-500 mesh sieve.

4. The method for recycling lithium manganese oxide batteries according to claim 1, characterized in that, The first stage of calcination is carried out at 300-400℃ for 1-3 hours in an inert protective atmosphere, followed by a second stage of calcination at 750-1000℃ for 20-60 minutes in an air atmosphere.

5. The method for recycling lithium manganese oxide batteries according to claim 1, characterized in that, It also includes the following steps: Acid leaching: The residue containing manganese, copper, iron, aluminum and graphite is mixed with water to make a slurry, and then acid is added to adjust the pH value to be stable at 1.0-2.0 for 20-40 minutes. The residue is then filtered to obtain graphite and solution.

6. The method for recycling lithium manganese oxide batteries according to claim 5, characterized in that, It also includes the following steps: Copper removal: Add reduced iron powder to the solution to remove copper, and filter to obtain sponge copper and copper-removed liquid; Separation: Add an oxidant to the solution after copper removal to oxidize the ferrous iron in the raffinate to ferric iron. Then, adjust the pH of the raffinate to 4.0-5.0 with sodium hydroxide, sodium carbonate or calcium carbonate. Filter to obtain slag containing lithium iron and a manganese solution containing calcium and magnesium. Extraction: Manganese in the manganese solution was extracted with C272 extractant, and the manganese salt solution was obtained after back-extraction. The solution was then concentrated and crystallized to obtain battery-grade manganese salt.

7. A method for recycling lithium manganese oxide batteries according to claim 6, characterized in that, In the acid leaching step, the slag containing manganese, copper, iron, aluminum and graphite is mixed with water to make a slurry, with a solid-liquid ratio of 1:3-1:

6. And / or, in the copper removal step, the amount of reduced 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 not greater than 0.005 g / L.

8. A method for recycling lithium manganese oxide batteries according to claim 6, characterized in that, In the acid leaching step, inorganic acid is added to adjust the pH value; And / or, the oxidant is sodium chlorate.

9. A method for recycling lithium manganese oxide batteries according to claim 8, characterized in that, The inorganic acid is hydrochloric acid or sulfuric acid.

10. A method for recycling lithium manganese oxide batteries according to claim 6, characterized in that, After back-extraction, a manganese sulfate or manganese chloride solution is obtained, which is then concentrated and crystallized to obtain battery-grade manganese sulfate or battery-grade manganese chloride.