Method for preparing manganous-manganic oxide by regenerating waste lithium manganate

Abstract

The invention relates to a method for preparing manganous-manganic oxide by regenerating waste lithium manganate, which comprises the following steps: 1) uniformly mixing waste lithium manganate with pure water and concentrated sulfuric acid to obtain slurry; (2) carrying out solid-liquid separation on the slurry obtained in the step (1), and then drying to obtain a dried product; (3) crushing the dried product obtained in the step (2), and sintering in an inert gas atmosphere; 4, after sintering is finished, cooling is conducted to the room temperature, pure water is added, stirring and water dissolving are conducted, solid-liquid separation is conducted again, filter residues are dried, and the manganous-manganic oxide is obtained.The method is easy to operate, waste gas and high-acid and high-alkali waste water are not generated in the recycling process, the technology is environmentally friendly, the manganese content of the prepared manganous-manganic oxide can reach 71.50% or above, the manganous-manganic oxide can be directly used for producing lithium manganate, and high performance is achieved.

Description

Technical Field

[0001] This invention belongs to the field of lithium-ion battery cathode material technology, specifically relating to a method for preparing manganese tetroxide by regenerating waste lithium manganese oxide. Background Technology

[0002] With the rapid development of the new energy industry, lithium-ion batteries, as a major energy storage method, are also facing the problem of how to achieve recycling. The large number of used batteries that cannot be effectively utilized not only represents a serious waste of resources but also causes irreversible environmental pollution.

[0003] Existing methods for recycling transition metal oxide cathode materials from spent lithium-ion batteries mainly include: pyrometallurgy, which recovers metals through high-temperature smelting, is simple to operate but generates a large amount of waste gas pollution; and hydrometallurgical extraction, which uses low-temperature leaching and separation purification to recover valuable metals, resulting in high purity. However, since lithium manganese oxide cathode materials only contain lithium and manganese, and manganese is inexpensive while the more expensive lithium accounts for a small proportion, the value generated by using traditional recycling methods is low, making industrialization difficult.

[0004] Based on this, the present invention has developed and provided a high-temperature sintering-wet process combined scheme for recycling and regenerating waste lithium battery cathode materials (lithium manganese oxide), thereby preparing high-purity manganese tetroxide. Summary of the Invention

[0005] The purpose of this invention is to overcome the shortcomings of existing technologies and provide a method for regenerating waste lithium manganese oxide to prepare manganese tetroxide. This method is simple to operate, produces no waste gas or highly acidic / alkaline wastewater during the recycling process, is environmentally friendly, and yields manganese tetroxide with a manganese content of over 71.50%, which can be directly used to produce lithium manganese oxide and achieve high performance.

[0006] To achieve the above objectives, the present invention adopts the following technical solution: A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: Step 1): Mix waste lithium manganese oxide with pure water and concentrated sulfuric acid until homogeneous to obtain a slurry; Step 2): After solid-liquid separation, the slurry obtained in Step 1) is dried to obtain the dried product; Step 3): The dried material obtained in Step 2) is crushed at high speed and placed in an atmosphere furnace for high-temperature sintering under an inert gas atmosphere; Step 4): After sintering, cool to room temperature, add a certain amount of pure water and stir to dissolve, then separate the solid and liquid again, dry the filter residue, and you will get the product.

[0007] Specifically, the waste lithium manganese oxide comes from at least one of the following: defective lithium manganese oxide products generated during the production process, lithium manganese oxide obtained from the recycling of positive electrode scraps in battery manufacturing, and lithium manganese oxide obtained from the recycling of waste batteries.

[0008] Furthermore, in step 1), the mass ratio of pure water to waste lithium manganese oxide is 1:1-3.

[0009] Furthermore, in step 1), the amount of concentrated sulfuric acid added is 25-35% of the mass of the waste lithium manganese oxide.

[0010] Further preferably, in step 1), the mixture is stirred at a speed of 30-60 Hz to achieve uniform mixing. Specifically, lithium manganese oxide can be placed in a reaction vessel, stirred at a speed of 30-60 Hz, and then pure water and concentrated sulfuric acid are added. After stirring evenly, a slurry is obtained.

[0011] Specifically, the drying process described in step 2) involves aging and drying the food in a desiccator at 90-150℃ for 10-20 hours.

[0012] Specifically, in step 3), high-temperature sintering is carried out under a nitrogen atmosphere at a temperature of 900-1100℃ and a holding time of 20-40 minutes.

[0013] Specifically, in step 4), the stirring time for water dissolution is 1-5 hours, then the residue is filtered and dried in a forced-air drying oven to obtain manganese tetroxide product.

[0014] This invention addresses the shortcomings of existing research on the recycling of lithium manganese oxide, a cathode material from waste lithium batteries. It provides a method for preparing manganese tetroxide (MnO) using substandard lithium manganese oxide generated during production, lithium manganese oxide recovered from cathode scraps in battery manufacturing, and lithium manganese oxide recycled from waste batteries, thus achieving resource recycling. The method involves placing lithium manganese oxide in a reaction vessel, adding pure water and concentrated sulfuric acid, and stirring. The resulting slurry is dried in a forced-air drying oven, crushed, and then placed in a sintering furnace for high-temperature sintering under a nitrogen atmosphere. After cooling, the sintered material is washed and filtered to obtain MnO. This method is simple, low-cost, and environmentally friendly. Furthermore, the obtained MnO can be directly used to produce lithium manganese oxide (e.g., the prepared MnO can be weighed according to the formula LiMn₂O₄, where the lithium source is lithium carbonate, held at 350°C for 5 hours, then heated to 700°C for 8 hours, cooled to room temperature in the furnace, crushed, and sieved to obtain lithium manganese oxide material).

[0015] Compared with the prior art, the advantages and beneficial effects of the present invention are as follows: This invention discloses a method for preparing manganese tetroxide from waste lithium manganese oxide. First, waste lithium manganese oxide black powder is mixed with water to form a slurry. Then, concentrated sulfuric acid is added and the mixture reacts. Next, the mixture is aged and dried. After drying, the material is crushed and sintered at high temperature under an inert atmosphere. The sintered material is then washed and dried to obtain the finished manganese tetroxide. This wet process for preparing manganese tetroxide from waste lithium manganese oxide is simpler to operate, produces no waste gas or highly acidic / alkaline wastewater during the recycling process, and is environmentally friendly. The resulting manganese tetroxide has a manganese content of over 71.50%, and can be directly used to produce lithium manganese oxide, achieving high performance. Attached Figure Description

[0016] Figure 1 The image shows the XRD pattern of manganese tetroxide prepared in Example 8. Detailed Implementation

[0017] The present invention will now be described in detail with reference to embodiments to facilitate understanding of the invention by those skilled in the art. It is particularly important to note that the embodiments are merely illustrative of the invention and should not be construed as limiting the scope of protection of the invention. Non-essential improvements and adjustments made to the invention by those skilled in the art based on the above description should still fall within the scope of protection of the present invention.

[0018] In the following examples, all raw materials used are common commercially available products that can be purchased directly, or can be prepared using conventional techniques in the art. For example, the waste lithium manganese oxide used in the examples is a substandard lithium manganese oxide product generated during the production process of Sodium Lithium Materials Technology Co., Ltd.

[0019] Concentrated sulfuric acid refers to sulfuric acid with a H2SO4 mass fraction of 98%. Room temperature refers to 25±5℃. Example 1

[0020] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 500g of pure water and stir at 300 r / min until it is evenly mixed. Then add 275.7g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer for aging and drying at 110℃ for 15 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 2

[0021] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 275.7g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer for aging and drying at 110℃ for 15 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 3

[0022] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 1000g of pure water, and stir at 300 r / min until the mixture is homogeneous. Then add 275.7g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer for aging and drying at 110℃ for 15 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 4

[0023] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 286.7g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 5

[0024] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 297.7g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 6

[0025] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 308.8g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 7

[0026] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 319.8g of concentrated sulfuric acid and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 8

[0027] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 319.8g of concentrated sulfuric acid and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:30mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide. Example 9

[0028] A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide includes the following steps: First, weigh 1000g of waste lithium manganese oxide, pour it into the reaction vessel, add 400g of pure water and stir at 300 r / min until it is evenly mixed. Then add 330.8g of concentrated sulfuric acid dropwise and stir until homogeneous; The slurry was discharged and transferred to a dryer to age and dry at 120°C for 12 hours. After cooling to room temperature, the material is discharged and crushed into no large agglomerates using a high-speed crusher. It is then placed in an atmosphere furnace and sintered at 1000℃ for 30 minutes under a nitrogen atmosphere with a gas flow rate of 3L / min. After cooling to room temperature, the mixture is stirred and dissolved in water at a solid-liquid ratio of 1g:10mL for 1 hour. After filtration, the solid is dried in a forced-air drying oven at 80℃, crushed, and sieved through a 300-mesh sieve to obtain the target product, manganese tetroxide.

[0029] The product manganese tetroxide prepared in the above examples was subjected to a titration experiment to test its main content.

[0030] The manganese tetroxide product obtained in Example 8 was subjected to XRD testing. The results are shown below. Figure 1 .from Figure 1 The XRD pattern shows that the prepared manganese tetroxide is pure phase manganese tetroxide.

[0031] The 0.1C discharge specific capacity of the manganese tetroxide product prepared in Example 8 was 131.26 mAh / g, which is comparable to the performance of commercially available manganese tetroxide products.

[0032] Table 1: Comparison of content between the examples and commercially available manganese tetroxide products

[0033] As can be seen from Table 1, the manganese content of the finished manganese tetroxide products prepared under different process conditions of the present invention is comparable to that of ordinary commercially available manganese tetroxide products, and the manganese content of some examples is even higher than that of ordinary commercially available manganese tetroxide products.

Claims

1. A method for preparing manganese tetroxide by regenerating waste lithium manganese oxide, characterized in that, Includes the following steps: Step 1): Mix waste lithium manganese oxide with pure water and concentrated sulfuric acid until homogeneous to obtain a slurry; Step 2): After solid-liquid separation, the slurry obtained in Step 1) is dried to obtain the dried product; Step 3): Crush the dried material obtained in Step 2) and sinter it in an inert gas atmosphere; Step 4): After sintering, cool to room temperature, add pure water and stir to dissolve, then separate the solid and liquid again, dry the filter residue, and you will get the product.

2. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, In step 1), the mass ratio of pure water to waste lithium manganese oxide is 1:1-3.

3. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, The waste lithium manganese oxide comes from at least one of the following: defective lithium manganese oxide products generated during the production process, lithium manganese oxide obtained from the recycling of positive electrode scraps in battery manufacturing, and lithium manganese oxide obtained from the recycling of waste batteries.

4. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, In step 1), the amount of concentrated sulfuric acid added is 25-35% of the mass of the waste lithium manganese oxide.

5. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, In step 1), mix thoroughly by stirring at a speed of 30-60 Hz.

6. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, The drying described in step 2) involves aging and drying in a desiccator at 90-150℃ for 10-20 hours.

7. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, In step 3), high-temperature sintering is carried out under a nitrogen atmosphere at a temperature of 900-1100℃ and a holding time of 20-40 minutes.

8. The method for preparing manganese tetroxide by regenerating waste lithium manganese oxide as described in claim 1, characterized in that, In step 4), the stirring time for water dissolution is 1-5 hours.

Images