Process and method for preparing battery-grade manganese sesquioxide from a manganese sulfate solution

Abstract

This invention discloses a process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution, belonging to the field of new energy battery materials and hydrometallurgical technology. The process uses a manganese sulfate solution as the manganese source and achieves one-step preparation of battery-grade manganese tetroxide through raw material preparation and process steps. The raw materials include a manganese sulfate solution (manganese concentration 40-130 g / L, low impurity content), a precipitant (10-35 wt% sodium hydroxide or 5-20 wt% ammonia), an oxidant (3-15 wt% hydrogen peroxide, air, or oxygen), a modifier (0-10 g / L, such as sodium tartrate, EDTA, etc.), and ammonium salts (0-30 g / L, such as ammonium sulfate, ammonium chloride, etc.). The process steps include: heating the reaction solution to 40-90℃, adjusting the pH to 7-10, continuously adding manganese sulfate solution, precipitant, and oxidant, controlling the pH change within ±0.3, reacting for 10-100 hours, stopping the manganese solution feed, maintaining the pH for 0.5 hours, and aging for 0.5-6 hours. After filtration, washing (conductivity ≤100μS / cm), and drying, the product is obtained. Wastewater is treated with a manganese precipitant (such as sodium carbonate) to recover manganese carbonate, and the solution is concentrated and crystallized to obtain sulfate byproducts. This invention features a short process flow, low cost, high product purity (manganese content ≥70%), controllable particle size, and high resource utilization, making it suitable for the production of cathode materials such as lithium manganese oxide and lithium manganese iron phosphate.

Description

Technical Field

[0001] This invention relates to the fields of new energy battery materials and hydrometallurgy, and more specifically, to a process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution method. Background Technology

[0002] In recent years, with the rapid development of the new energy power battery industry, Mn3O4 has gradually replaced MnO2 as the main raw material for the cathode material of lithium manganese oxide (LiMn2O4) batteries. Simultaneously, with the research on lithium manganese iron phosphate cathode materials, Mn3O4, due to its good particle size uniformity and spinel structure, has also gradually become a key raw material under consideration. Traditional methods for preparing Mn3O4 mainly include pyrometallurgical and hydrometallurgical processes. Currently, the hydrometallurgical process mostly uses the oxidation method of manganese powder suspension. This method is relatively mature, but it has a long process, high production cost, low purity, and uneven particle size, often resulting in incomplete oxidation and Mn content exceeding the theoretical value. Therefore, to address the various shortcomings of existing technologies, this application proposes a process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution method. This shortens the overall process from manganese ore to Mn3O4, and the prepared Mn3O4 product not only has high purity but also allows for controllable particle size, which is more beneficial for the preparation and performance improvement of downstream cathode materials. Therefore, this application is hereby submitted. Summary of the Invention

[0003] The purpose of this invention is to provide a process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution method, in order to solve the problems of high raw material cost, low purity, difficulty in particle size control, and incomplete oxidation in the existing metal manganese suspension method for preparing battery-grade manganese tetroxide.

[0004] The technical problem solved by this invention is achieved by the following technical solution:

[0005] 1. A process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution method, characterized in that the process and method include: 1) Preparation of raw materials: the raw materials include manganese sulfate solution, precipitant, oxidant, reaction base liquid, adjuster, and ammonium salt. A manganese sulfate solution of a certain quality and concentration is prepared. A certain amount of adjuster can be added to the manganese sulfate solution, with the adjuster concentration added at 0-10 g / L. At the same time, a sodium hydroxide solution with a concentration of 10-35 wt% or an ammonia solution with a concentration of 5-20 wt% is prepared as a precipitant, and hydrogen peroxide or air or oxygen with a concentration of 3-15 wt% is prepared as an oxidant. The reaction base liquid is pure water. Depending on the choice of alkali solution, an ammonium salt concentration of 0-30 g / L is prepared in the reaction base liquid or manganese sulfate solution. 2) Process Steps: Place the reaction base liquid in the reactor, with the liquid level slightly higher than the stirring blades. Turn on the stirring and set the stirring intensity. Heat the reaction base liquid to the target temperature. Add alkali solution to the reactor and adjust the pH to the target value. Simultaneously, add manganese sulfate solution, alkali solution, and oxidant using a continuous feeding method. Control the reaction pH at 7-10 by adjusting the alkali solution flow rate, and maintain the pH change of the reaction system within ±0.3. Continue the reaction for 10-100 hours. Stop feeding manganese sulfate solution, but continue feeding alkali solution to maintain the pH of the reaction system for 0.5 hours. Stop feeding alkali solution and continue feeding oxidant to age the battery-grade manganese tetroxide slurry for 0.5-6 hours. Filter, wash, dry, and package the battery-grade manganese tetroxide product to obtain manganese tetroxide product. After manganese is precipitated by a manganese precipitating agent in the production wastewater and washing wastewater, manganese carbonate is obtained. The manganese precipitated solution is concentrated and crystallized to obtain sulfate by-products.

[0006] 2. In the above technical solution, as a preferred embodiment, the manganese concentration of the manganese sulfate solution is 40-130 g / L, the Ca and Mg impurity content of the manganese sulfate solution is less than 300 mg / L, the K impurity content is less than 10 mg / L, the Fe, Cu, Ni, and Zn content is less than 3 mg / L, the TOC is less than 8 mg / L, and the pH is 3.5-6.

[0007] 3. In the above technical solution, as a preferred embodiment, the precipitant is one or more of sodium hydroxide and ammonia water, wherein the concentration of sodium hydroxide is 10-35 wt% and the concentration of ammonia water is 5-20 wt%.

[0008] 4. In the above technical solution, as a preferred method, the modifier and ammonium salt can be added in one or more places, such as the reaction base liquid, manganese sulfate solution, and alkaline solution.

[0009] 5. In the above technical solution, as a preferred embodiment, the modifier is one or more of sodium tartrate, ammonium dodecyl sulfate, SDS, PVP, CTAB, PEG2000, EDTA, and citric acid.

[0010] 6. In the above technical solution, as a preferred embodiment, the ammonium salt is one or more of ammonium sulfate, ammonium chloride, ammonium nitrate, ammonium fluoride, ammonium bromide, and ammonium phosphate.

[0011] 7. In the above technical solution, as a preferred embodiment, the manganese precipitant is one or more of sodium carbonate, sodium bicarbonate, and ammonium bicarbonate.

[0012] 8. In the above technical solution, as a preferred embodiment, the stirring intensity of the stirring blade is 120-450 r / min.

[0013] 9. In the above technical solution, as a preferred embodiment, the washing process uses pure water for washing, and the washing wastewater conductivity is ≤100μS / cm as the washing endpoint.

[0014] 10. In the above technical solution, as a preferred embodiment, the by-product is ammonium sulfate or sodium sulfate, depending on the precipitant.

[0015] 11. In the above technical solution, as a preferred embodiment, the target temperature is 40-90℃.

[0016] As can be seen from the above technical solution, compared with the prior art, the present invention has the following beneficial effects:

[0017] 1. The present invention discloses a process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution. This method uses manganese sulfate solution as the manganese source and prepares battery-grade manganese tetroxide in one step. The process is simple, the product purity is higher, and the product indicators are controllable.

[0018] 2. This invention avoids the need for adding seed crystals to promote the synthesis of battery-grade manganese tetroxide products in existing technologies.

[0019] 3. By changing the way the modifier and ammonium salt are added, this invention promotes the stability of the reaction system and makes the production process more stable.

[0020] 4. The battery-grade manganese tetroxide product prepared by this invention has controllable quality and can be supplied according to market demand.

[0021] 5. The wastewater generated by this invention can be further treated to obtain manganese carbonate, ammonium sulfate, or sodium sulfate as byproducts, thereby improving resource utilization. Attached Figure Description

[0022] Figure 1 This is a schematic flow diagram of the process and method for preparing battery-grade manganese tetroxide using a manganese sulfate solution method according to the present invention; Figure 2 This is an electron microscope image of the battery-grade manganese tetroxide product obtained in Example 1; Figure 3 This is an electron microscope image of the battery-grade manganese tetroxide product obtained in Comparative Example 1; Figure 4 This is an electron microscope image of the battery-grade manganese tetroxide product obtained in Example 2; Figure 5 This is an electron microscope image of the battery-grade manganese tetroxide product obtained in Comparative Example 2. Detailed Implementation

[0023] The present invention will be further described in detail below with reference to the embodiments. Example

[0024] This embodiment is prepared in the laboratory. The process and method for preparing battery-grade manganese tetroxide by manganese sulfate solution includes the following steps: 1) Preparation of raw materials: Take a deeply purified solution to prepare an 80 g / L high-purity manganese sulfate solution, and add an adjusting agent to the manganese sulfate solution to prepare an adjusting agent concentration of 0 g / L; take analytical grade ammonia water to prepare a 9 wt% concentration; take analytical grade hydrogen peroxide to prepare a 3 wt% concentration; take a certain amount of pure water to prepare an ammonium salt with a concentration of 0 g / L as the reaction base liquid. 2) Process Steps: Place the reaction base liquid in a 5L reactor, with the liquid level slightly above the stirring blades. Turn on the stirring and set the stirring intensity to 200 r / min. Heat the reaction base liquid to 60℃. Add ammonia water to the reactor using a peristaltic pump to adjust the pH to 7.5. Simultaneously, slowly and continuously add manganese sulfate solution and hydrogen peroxide to the reactor at a stable flow rate using a peristaltic pump. Maintain the pH change of the reaction system within ±0.3 by adjusting the ammonia water flow rate. Continue the reaction for at least 10 hours. Stop feeding manganese sulfate solution, but continue feeding alkali solution to maintain the pH of the reaction system for 0.5 hours. Stop feeding alkali solution, but continue feeding hydrogen peroxide for aging for 3 hours. Filter, wash, and dry the slurry to obtain battery-grade manganese tetroxide. Add sodium carbonate to the filtration and washing wastewater and react for 0.5 hours. Filter to obtain solid manganese carbonate. After pressure filtration, concentrate and crystallize the solution to obtain ammonium sulfate as a byproduct.

[0025] The battery-grade manganese tetroxide prepared in this embodiment has a manganese content of 70.36%, a particle size D50 of 23.06 μm, a BET of 1.06 m² / g, and a tap density of 2.73 g / cm³. The microstructure of this product is as follows: Figure 2 As shown.

[0026] Comparative Example 1

[0027] This comparative example was prepared in the laboratory. The process and method for preparing battery-grade manganese tetroxide by manganese sulfate solution includes the following steps: 1) Preparation of raw materials: Take a deeply purified solution to prepare an 80 g / L high-purity manganese sulfate solution, and add an adjusting agent to the manganese sulfate solution to prepare an adjusting agent concentration of 3 g / L; take analytical grade ammonia water to prepare a 9 wt% concentration; take analytical grade hydrogen peroxide to prepare a 3 wt% concentration; take a certain amount of pure water to prepare an ammonium salt with a concentration of 0 g / L as the reaction base liquid. 2) Process Steps: Place the reaction base liquid in a 5L reactor, with the liquid level slightly above the stirring blades. Turn on the stirring and set the stirring intensity to 450 r / min. Heat the reaction base liquid to 60℃. Add ammonia water to the reactor using a peristaltic pump to adjust the pH to 7.5. Simultaneously, slowly and continuously add manganese sulfate solution and hydrogen peroxide to the reactor at a stable flow rate using a peristaltic pump. Maintain the pH change of the reaction system within ±0.3 by adjusting the ammonia water flow rate. Continue the reaction for at least 10 hours. Stop feeding manganese sulfate solution, but continue feeding alkali solution to maintain the pH of the reaction system for 0.5 hours. Stop feeding alkali solution, but continue feeding hydrogen peroxide for aging for 3 hours. Filter, wash, and dry the slurry to obtain battery-grade manganese tetroxide. Add sodium carbonate to the filtration and washing wastewater and react for 0.5 hours. Filter to obtain solid manganese carbonate. After pressure filtration, concentrate and crystallize the solution to obtain ammonium sulfate as a byproduct.

[0028] The battery-grade manganese tetroxide prepared in this comparative example has a manganese content of 70.23%, a particle size D50 of 7.13 μm, a BET of 0.29 m² / g, and a tap density of 2.62 g / cm³. The microstructure of this product is as follows: Figure 3 As shown. Example

[0029] This embodiment is prepared on a pilot production line. The process and method for preparing battery-grade manganese tetroxide using the manganese sulfate solution method includes the following steps: 1) Raw material preparation: Prepare a 100g / l high-purity manganese sulfate solution for the production line and place it in a manganese sulfate solution tank. Add EDTA as an adjuster to the manganese sulfate solution to prepare an EDTA concentration of 1.5g / l. Add ammonium sulfate to the manganese sulfate solution to prepare a concentration of 0.25g / l. Prepare 32% industrial liquid alkali and place it in an alkali solution tank. Prepare 4.5m³ of reaction base solution with a concentration of 0.5g / l of ammonium sulfate using pure water. The oxidant is air, which is introduced into the reaction solution through an air pipe using a Roots blower. 2) Process steps: Place 4.5 m³ of reaction base liquid into a 15 m³ reactor, start stirring, set the stirring intensity of the stirring blades to 200 r / min, heat the reaction base liquid to 60℃, add liquid alkali into the reactor using a metering pump, and adjust the pH to 8.5; start the Roots blower to supply air to the reactor, set the air flow rate to 240 m³ / h, start the manganese sulfate solution feed pump to feed the reactor, and at the same time switch the PLC control system from manual to automatic, control the liquid alkali feed rate through the system to ensure the pH stability of the reaction system, monitor the particle size distribution of the product during the process, and continuously feed the reaction for more than 25 hours; the crystal particle size gradually grows, and after the product particle size D50 reaches the expected value, stop the manganese sulfate solution feed pump, continue to feed the alkali solution to maintain the pH of the reaction system for 0.5 hours, stop the alkali solution feed, and continue to feed air for aging for 4 hours; filter, wash and dry the slurry to obtain battery-grade manganese tetroxide product. The filtration and washing wastewater is fed into a manganese precipitation tank, and ammonium bicarbonate is added to the tank and reacted for 0.5 hours. After filtration and drying, solid manganese carbonate is obtained. The solution after pressure filtration is concentrated and crystallized to obtain sodium sulfate as a byproduct.

[0030] The battery-grade manganese tetroxide prepared in this embodiment has a manganese content of 70.85%, a particle size D50 of 6.63 μm, a BET of 0.40 m² / g, and a true density of 2.60 g / cm³. The microstructure of this product is as follows: Figure 4 As shown.

[0031] Comparative Example 2

[0032] This comparative example was prepared on a pilot production line. The process and method for preparing battery-grade manganese tetroxide using the manganese sulfate solution method includes the following steps: 1) Raw material preparation: 100 g / L high-purity manganese sulfate solution is prepared in a manganese sulfate solution tank, and EDTA is added to the manganese sulfate solution to prepare an EDTA concentration of 1.5 g / L; 32% industrial liquid alkali is prepared in an alkali solution tank; 4.5 m³ of reaction base solution with a concentration of 0.5 g / L ammonium sulfate is prepared using pure water; the oxidant is air, which is introduced into the reaction solution through an air pipe using a Roots blower. 2) Process steps: Place 4.5 m³ of reaction base liquid into a 15 m³ reactor, start stirring, set the stirring intensity of the stirring blades to 180 r / min, heat the reaction base liquid to 60℃, add liquid alkali into the reactor using a metering pump, and adjust the pH to 8.5; start the Roots blower to supply air to the reactor, set the air flow rate to 240 m³ / h, start the manganese sulfate solution feed pump to feed the reactor, and at the same time switch the PLC control system from manual to automatic, control the liquid alkali feed rate through the system to ensure the pH of the reaction system is stable, monitor the particle size distribution of the product during the process, and continuously feed the reaction for more than 25 hours; the crystal particle size gradually grows, and after the product particle size D50 reaches the expected value, stop the manganese sulfate solution feed pump, continue to feed the alkali solution to maintain the pH of the reaction system for 0.5 hours, stop the alkali solution feed, and continue to feed air for aging for 4 hours; filter, wash and dry the slurry to obtain battery-grade manganese tetroxide product. The filtration and washing wastewater is fed into a manganese precipitation tank, and ammonium bicarbonate is added to the tank and reacted for 0.5 hours. After filtration and drying, solid manganese carbonate is obtained. The solution after pressure filtration is concentrated and crystallized to obtain sodium sulfate as a byproduct.

[0033] The battery-grade manganese tetroxide prepared in this comparative example has a manganese content of 70.27%, a particle size D50 of 6.58 μm, a BET of 0.74 m² / g, and a tap density of 2.38 g / cm³. The microstructure of this product is as follows: Figure 5 As shown.

[0034] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution, characterized in that: The process and method include: 1) Raw material preparation: The raw materials include manganese sulfate solution, precipitant, oxidant, reaction base liquid, adjuster, and ammonium salt. A manganese sulfate solution of a certain quality and concentration is prepared. A certain amount of adjuster can be added to the manganese sulfate solution. The concentration of the adjuster is added at 0-10 g / L. At the same time, a sodium hydroxide solution with a concentration of 10-35 wt% or an ammonia solution with a concentration of 5-20 wt% is prepared as a precipitant, and hydrogen peroxide or air or oxygen with a concentration of 3-15 wt% is prepared as an oxidant. The reaction base liquid is pure water. Depending on the choice of alkali solution, an ammonium salt concentration of 0-30 g / L is prepared in the reaction base liquid or manganese sulfate solution. 2) Process Steps: Place the reaction base liquid in the reactor, with the liquid level slightly higher than the stirring blades. Turn on the stirring and set the stirring intensity. Heat the reaction base liquid to the target temperature. Add alkali solution to the reactor and adjust the pH to the target value. Simultaneously, add manganese sulfate solution, alkali solution, and oxidant using a continuous feeding method. Control the reaction pH at 7-10 by adjusting the alkali solution flow rate, and maintain the pH change of the reaction system within ±0.

3. Continue the reaction for 10-100 hours. Stop feeding manganese sulfate solution, but continue feeding alkali solution to maintain the pH of the reaction system for 0.5 hours. Stop feeding alkali solution and continue feeding oxidant to age the battery-grade manganese tetroxide slurry for 0.5-6 hours. Filter, wash, dry, and package the battery-grade manganese tetroxide product to obtain manganese tetroxide product. After manganese is precipitated by a manganese precipitating agent in the production wastewater and washing wastewater, manganese carbonate is obtained. The manganese precipitated solution is concentrated and crystallized to obtain sulfate by-products.

2. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The manganese sulfate solution has a manganese concentration of 40-130 g / L, and the contents of Ca and Mg impurities are both less than 300 mg / L, the contents of K impurities are less than 10 mg / L, the contents of Fe, Cu, Ni, and Zn are less than 3 mg / L, the TOC is less than 8 mg / L, and the pH is 3.5-6.

3. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The precipitant is one or more of sodium hydroxide and ammonia, wherein the concentration of sodium hydroxide is 10-35 wt% and the concentration of ammonia is 5-20 wt%.

4. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The modifier and ammonium salt can be added to one or more of the reaction substrate, manganese sulfate solution, and alkaline solution.

5. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The modifier is one or more of sodium tartrate, ammonium dodecyl sulfate, SDS, PVP, CTAB, PEG2000, EDTA, and citric acid.

6. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The ammonium salt is one or more of ammonium sulfate, ammonium chloride, ammonium nitrate, ammonium fluoride, ammonium bromide, and ammonium phosphate.

7. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The manganese precipitating agent is one or more of sodium carbonate, sodium bicarbonate, and ammonium bicarbonate.

8. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The stirring intensity of the stirring blades is 120-450 r / min.

9. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The washing process uses pure water and the washing wastewater conductivity is ≤100μS / cm as the washing endpoint.

10. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The byproducts are either ammonium sulfate or sodium sulfate, depending on the precipitant used.

11. The process and method for preparing battery-grade manganese tetroxide using manganese sulfate solution according to claim 1, characterized in that, The target temperature is 40-90℃.

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