Method for preparing battery-grade manganous-manganic oxide from low-grade manganese carbonate ore

Abstract

The invention relates to the technical field of utilization of low-grade manganese carbonate ore and preparation of manganous-manganic oxide, and provides a method for preparing battery-grade manganous-manganic oxide from low-grade manganese carbonate ore, which comprises the following steps: carrying out sulfuric acid leaching and impurity removal on the low-grade manganese carbonate ore to obtain a magnesium-containing manganese sulfate solution; mixing the magnesium-containing manganese sulfate solution with ammonia water, and carrying out precipitation oxidation to obtain a reaction solution; aging the reaction solution to obtain an aged solution; the aged liquid is subjected to thickening treatment, overflow liquid and underflow concentrated liquid are obtained, the overflow liquid serves as reaction base liquid to be mixed with a surfactant, and then the mixture is returned to precipitation oxidation; and filtering, washing and drying the underflow concentrated solution to obtain the battery-grade manganous-manganic oxide. The method provided by the invention at least achieves the effects that high-tap-density doped battery-grade manganous-manganic oxide can be directly prepared without deep magnesium removal, and the manganese-based battery material prepared by taking the manganous-manganic oxide as the precursor has more excellent charge-discharge performance.

Description

Technical Field

[0001] This disclosure relates to the fields of utilization of low-grade manganese carbonate ore and preparation of manganese tetroxide, for example, to a method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore. Background Technology

[0002] Manganese is one of the most widely used elements in cathode materials, possessing considerable development potential due to its non-toxicity, low cost, and high capacity. Manganese tetroxide (Mt. tetroxide) is an important precursor for lithium manganese oxide cathode materials; therefore, the industrial-scale preparation of battery-grade Mt. tetroxide plays a significant role in promoting the development of the new energy industry. Manganese ore is one of the essential bulk raw materials for industrial production. It is not only a basic raw material for the steel industry but also a crucial raw material supporting the development of emerging industries such as new energy and new materials, making it a vital strategic material for national economic construction. The manganese ore method for preparing Mt. tetroxide involves processing the raw manganese ore through reduction and acid leaching to obtain a manganese salt solution, and then preparing the Mt. tetroxide product using the manganese salt method. Because it starts from the raw ore, it is low-cost and has high economic value, making it a research hotspot in the industry.

[0003] However, most of China's manganese ore resources are characterized by low grade and high impurity content. Taking a typical low-grade manganese carbonate ore from Tongren, Guizhou, China's largest manganese resource base, as an example, the manganese grade is about 12%, and the magnesium oxide content reaches over 2%. This means that during the manganese ore leaching process to produce manganese tetroxide, magnesium is converted into magnesium sulfate impurities and enters the manganese sulfate solution along with the manganese leaching process. To address this, relevant technologies generally employ deep impurity removal methods to obtain a high-purity manganese sulfate solution (e.g., a manganese-magnesium ratio greater than 2000) to ensure that subsequent processes produce qualified manganese tetroxide products that meet current requirements.

[0004] For example, Chinese patent document CN119461491A discloses a method for preparing manganese sulfate crystals and manganese tetroxide using manganese carbonate ore. The method for preparing manganese sulfate crystals includes: slurrying manganese carbonate ore, adding sulfuric acid for leaching, and simultaneously adding an oxidizing agent to obtain a leachate; adding a deweighting agent to the leachate, reacting for a preset time, filtering, adding a neutralizing agent to the filtrate, and then filtering again to obtain a manganese sulfate solution; reacting the manganese sulfate solution with a precipitant, filtering, and then washing the precipitate with hot water slurry to obtain a washed precipitate; dissolving the washed precipitate in sulfuric acid, adding manganese fluoride, filtering, adding a defluorinating agent to the filtrate, filtering again, and then evaporating and crystallizing to obtain manganese sulfate crystals. Results show that the manganese sulfate crystals prepared by this method have a manganese-to-magnesium ratio of approximately 10000, and the battery-grade manganese tetroxide prepared using these manganese sulfate crystals has a tap density greater than 2.3 g / cm³. 3It can be seen that although the method provided in the above patent literature can produce high-purity manganese sulfate crystals, its extremely high requirement for the manganese-magnesium ratio will inevitably lead to drawbacks such as high difficulty in impurity removal and complex impurity removal steps, resulting in very high production costs.

[0005] In summary, given the poor quality of manganese ore in China and the difficulty and high cost of magnesium removal using existing manganese sulfate solutions, there is an urgent need for a method to directly produce battery-grade manganese tetroxide without deep magnesium removal, thereby promoting the efficient and short-process utilization of typical low-grade manganese carbonate resources. Summary of the Invention

[0006] The purpose of this disclosure is to overcome the shortcomings of the prior art and provide a method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore, so as to at least achieve the effect of directly preparing high-tap-density doped battery-grade manganese tetroxide without deep magnesium removal, and the manganese-based battery materials prepared by using it as a precursor have better charge and discharge performance.

[0007] The purpose of this disclosure is achieved through the following technical solution:

[0008] On the one hand, a method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore is provided. The method includes: leaching the low-grade manganese carbonate ore with sulfuric acid and removing impurities to obtain a magnesium-containing manganese sulfate solution; mixing the magnesium-containing manganese sulfate solution with ammonia water and performing precipitation oxidation to obtain a reaction solution; aging the reaction solution to obtain an aged solution; thickening the aged solution to obtain an overflow and a bottom concentrate; wherein the overflow is used as the reaction bottom solution, mixed with a surfactant, and returned to the precipitation oxidation; and filtering, washing, and drying the bottom concentrate to obtain the battery-grade manganese tetroxide.

[0009] It is worth noting that the method provided in this disclosure can significantly reduce the requirement for magnesium ion content in the magnesium-containing manganese sulfate solution obtained after sulfuric acid leaching and impurity removal (e.g., reducing the requirement for the manganese-magnesium ratio from the conventional greater than 2000 to 120-1000). This not only shortens the production process and reduces costs, but also achieves synergistic utilization of magnesium resources. Furthermore, the method provided in this disclosure, through the thickening process, allows fine-particle manganese tetroxide to be more easily returned to the precipitate oxidation along with the overflow liquid and used for the synthesis of manganese tetroxide. At the same time, the fine-particle manganese tetroxide can also provide reaction seeds for the next stage of reaction. This not only makes full use of manganese resources, but also is more conducive to the formation of more regular manganese tetroxide crystals, thereby making the prepared battery-grade manganese tetroxide have a higher tap density.

[0010] It should be noted that the purpose of the sulfuric acid leaching is only to decompose and extract manganese from the low-grade manganese carbonate ore to obtain manganese sulfate solution. In order to achieve the above purpose, there are many methods that can be selected. Those skilled in the art can combine relevant technologies and make adaptive selections according to actual needs. This disclosure does not limit this.

[0011] In some examples, the sulfuric acid leaching conditions include: a sulfuric acid concentration of 1 mol / L, a liquid-to-solid ratio of 3:1, a leaching temperature of 60°C, and a leaching time of 30 min.

[0012] Similarly, the purpose of the impurity removal is merely to remove heavy metals, iron, aluminum, calcium, magnesium and other impurities from the manganese sulfate solution obtained by the sulfuric acid leaching. In order to achieve the above purpose, there are many methods that can be selected. Those skilled in the art can combine relevant technologies and make adaptive selections according to actual needs. This disclosure does not limit this.

[0013] In some examples, the impurity removal methods include: hydroxide precipitation, sulfide precipitation, and fluoride precipitation.

[0014] It should be noted that the purpose of the hydroxide precipitation for impurity removal is to remove impurities such as iron and aluminum, the purpose of the sulfide precipitation for impurity removal is to remove the main heavy metal impurities, and the purpose of the fluoride precipitation for impurity removal is to remove impurities such as calcium and magnesium.

[0015] It should be understood that although the various impurity removal methods used in the impurity removal process can achieve the purpose of removing the corresponding impurities, the actual impurity removal effect will vary depending on the impurity removal steps and conditions. Specifically, the higher the requirement for the impurity removal effect, the more complex the impurity removal steps and conditions required; the lower the requirement for the impurity removal effect, the simpler the impurity removal steps and conditions required.

[0016] In some embodiments, the content of Mn in the magnesium-containing manganese sulfate solution is 60–120 g / L, and the content of Mg is 0.12–0.5 g / L.

[0017] In some embodiments, air is introduced during the precipitation oxidation process.

[0018] In some embodiments, the pH of the precipitation oxidation is 8-10, the temperature of the precipitation oxidation is 60-90°C, and the precipitation oxidation time is 4-30 hours.

[0019] In some embodiments, the aging time is 1 to 4 hours.

[0020] In some embodiments, the surfactant includes at least one of polyethylene glycol, sodium dodecyl sulfonate, and sodium dodecylbenzene sulfonate.

[0021] It should be noted that the method provided in this disclosure, by adding the surfactant, is beneficial to forming spherical manganese tetroxide with a more uniform morphology and a more obvious agglomeration effect; on this basis, by further limiting the type of surfactant, the above effect can be made more significant.

[0022] In some embodiments, the weight ratio of the surfactant to the reaction substrate is 1 to 6:100.

[0023] In some embodiments, the drying temperature is 100–200°C, and the drying time is 2–6 hours.

[0024] In some embodiments, the low-grade manganese carbonate ore contains 10% to 15% Mn and 1% to 6% Mg.

[0025] The beneficial effects of this disclosure are:

[0026] 1. The present disclosure provides a method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore, which can significantly reduce the requirement for magnesium ion content in the magnesium-containing manganese sulfate solution obtained after sulfuric acid leaching and impurity removal. This not only shortens the production process and reduces costs, but also achieves the synergistic utilization of magnesium resources.

[0027] 2. The method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore provided in this disclosure has the characteristics of low cost, high tap density, and good magnesium doping uniformity. Furthermore, lithium-based battery materials prepared using manganese tetroxide as a precursor have superior charge and discharge performance. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in this disclosure, the accompanying drawings used in some embodiments of this disclosure will be briefly described below. Obviously, the drawings described below are merely drawings of some embodiments of this disclosure, and those skilled in the art can obtain other drawings based on these drawings. Furthermore, the drawings described below can be regarded as schematic diagrams and are not intended to limit the actual process of the methods involved in the embodiments of this disclosure.

[0029] Figure 1 This is a process flow diagram of a method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore according to some embodiments. Detailed Implementation

[0030] The technical solutions in some embodiments of this disclosure will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of this disclosure, and not all embodiments. Based on the embodiments provided in this disclosure, all other embodiments obtained by those skilled in the art are within the scope of protection of this disclosure.

[0031] Unless the context otherwise requires, throughout the specification and claims, the term "comprising" is interpreted as open and encompassing, that is, "including, but not limited to".

[0032] In describing some embodiments, the expressions "at least one of A, B and C" and "at least one of A, B or C" may be used, both of which have the same meaning and include the following combinations of A, B and C: only A, only B, only C, a combination of A and B, a combination of A and C, a combination of B and C, and a combination of A, B and C.

[0033] Example 1

[0034] A method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore, the main process of which is as follows: Figure 1 As shown, it includes:

[0035] S1. Low-grade manganese carbonate ore (Mn content 13.35%, Mg content 1.15%) was leached with sulfuric acid to obtain a leachate. After removing impurities from the leachate, a magnesium-containing manganese sulfate solution (Mn content 105 g / L, Mg content 0.12 g / L) was obtained.

[0036] S2. Magnesium manganese sulfate solution and ammonia water are added to the reactor simultaneously using a two-liquid co-current addition method. Air is introduced to carry out precipitation oxidation. The reaction pH is controlled at 9.5, the reaction temperature at 80℃, and the reaction time at 20h to obtain the reaction solution.

[0037] S3. After aging the reaction solution for 2 hours, it is transferred to a thickener for concentration and classification (i.e., thickening treatment) to obtain an overflow containing fine manganese tetroxide particles and a bottom concentrate with a high manganese tetroxide content. The overflow is used as the reaction base liquid for synthesizing manganese tetroxide, and sodium dodecylbenzenesulfonate is used as a surfactant. The two are mixed at a mass ratio of sodium dodecylbenzenesulfonate:overflow = 2:100 and returned to the reaction vessel in S2 for precipitation oxidation.

[0038] S4. The underflow concentrate was filtered and thoroughly washed, then dried at 120℃ for 4 hours to obtain high-tap-density magnesium-doped battery-grade manganese tetroxide (Mn content 71.80%, Mg content 0.08%, tap density 2.71 g / cm³). 3 ).

[0039] Example 2

[0040] A method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore, the main process of which is as follows: Figure 1 As shown, it includes:

[0041] S1. Low-grade manganese carbonate ore (Mn content 11.75%, Mg content 5.06%) was leached with sulfuric acid to obtain a leachate. After removing impurities from the leachate, a magnesium-containing manganese sulfate solution (Mn content 60 g / L, Mg content 0.5 g / L) was obtained.

[0042] S2. Magnesium manganese sulfate solution and ammonia water are added to the reactor simultaneously using a two-liquid co-current addition method. Air is introduced to carry out precipitation oxidation. The reaction pH is controlled at 8, the reaction temperature at 60℃, and the reaction time at 4h to obtain the reaction solution.

[0043] S3. After aging the reaction solution for 1 hour, it is transferred to a thickener for concentration and classification (i.e., thickening treatment) to obtain an overflow containing fine manganese tetroxide particles and a bottom concentrate with a high manganese tetroxide content. The overflow is used as the reaction base liquid for synthesizing manganese tetroxide, and polyethylene glycol is used as a surfactant. The two are mixed at a mass ratio of polyethylene glycol:overflow = 1:100 and returned to the reaction vessel in S2 for precipitation and oxidation.

[0044] S4. The underflow concentrate was filtered and thoroughly washed, then dried at 200℃ for 2 hours to obtain high-tap-density magnesium-doped battery-grade manganese tetroxide (Mn content 70.65%, Mg content 0.99%, tap density 2.48 g / cm³). 3 ).

[0045] Example 3

[0046] A method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore, the main process of which is as follows: Figure 1 As shown, it includes:

[0047] S1. Low-grade manganese carbonate ore (Mn content 15.78%, Mg content 2.05%) was leached with sulfuric acid to obtain a leachate. After removing impurities from the leachate, a magnesium-containing manganese sulfate solution (Mn content 120 g / L, Mg content 0.48 g / L) was obtained.

[0048] S2. Magnesium manganese sulfate solution and ammonia water are added to the reactor simultaneously using a two-liquid co-current addition method. Air is introduced to carry out precipitation oxidation. The reaction pH is controlled at 10, the reaction temperature at 90℃, and the reaction time at 30h to obtain the reaction solution.

[0049] S3. After aging the reaction solution for 4 hours, it is transferred to a thickener for concentration and classification (i.e., thickening treatment) to obtain an overflow containing fine manganese tetroxide particles and a bottom concentrate with a high manganese tetroxide content. The overflow is used as the reaction base liquid for synthesizing manganese tetroxide, and sodium dodecyl sulfonate is used as a surfactant. The two are mixed at a mass ratio of sodium dodecyl sulfonate:overflow = 6:100 and returned to the reaction vessel in S2 for precipitation oxidation.

[0050] S4. The underflow concentrate was filtered and thoroughly washed, then dried at 100℃ for 6 hours to obtain high-tap-density magnesium-doped battery-grade manganese tetroxide (Mn content 71.55%, Mg content 0.24%, tap density 2.78 g / cm³). 3 ).

[0051] Compare with Example 1

[0052] Comparison was made between Comparative Example 1 and Example 3. Comparative Example 1 used the low-grade manganese carbonate ore from Example 3. The difference between Comparative Example 1 and Example 3 is that the Mn content of the low-magnesium manganese sulfate solution obtained after deep purification of the leaching solution in S1 is 120 g / L and the Mg content is 12 mg / L. Other conditions, such as the selection and dosage of reagents, as well as the specific steps and condition parameters of the process, are the same as those in Example 3.

[0053] It is understood that the manganese-magnesium ratio in the low-magnesium manganese sulfate solution in this comparative example is 10000, while the manganese-magnesium ratio in the magnesium-containing manganese sulfate solution in Example 3 is 1000. That is, compared with Example 3, this comparative example significantly improves the manganese-magnesium ratio by performing deep magnesium removal, which is used to prove that the method of this disclosure is more effective.

[0054] The results showed that the battery-grade manganese tetroxide prepared using the method of Comparative Example 1 had a Mn content of 71.65%, a Mg content of 0.005%, and a tap density of 2.77 g / cm³. 3 .

[0055] Compare with Example 2

[0056] Comparative Example 2 and Example 3 were used. In Comparative Example 2, the low-grade manganese carbonate ore in Example 3 was used. The difference between Comparative Example 2 and Example 3 is that the Mn content of the low-magnesium manganese sulfate solution obtained after deep purification of the leaching solution in S1 is 120 g / L and the Mg content is 0.06 g / L. Other conditions, such as the selection and dosage of reagents, as well as the specific steps and condition parameters of the process, are the same as those in Example 3.

[0057] It is understood that the manganese-magnesium ratio in the low-magnesium manganese sulfate solution in this comparative example is 2000, while the manganese-magnesium ratio in the magnesium-containing manganese sulfate solution in Example 3 is 1000. That is, compared with Example 3, this comparative example significantly improves the manganese-magnesium ratio by performing deep magnesium removal, which is used to prove that the method of this disclosure is more effective.

[0058] The results showed that the battery-grade manganese tetroxide prepared using the method of Comparative Example 2 had a Mn content of 71.58%, a Mg content of 0.025%, and a tap density of 2.77 g / cm³. 3 .

[0059] Compare with Example 3

[0060] A comparison was made between Comparative Example 3 and Example 3, wherein Comparative Example 3 used the low-grade manganese carbonate ore of Example 3. The difference between Comparative Example 3 and Example 3 is as follows:

[0061] 1) Replace S3 with S3': Use an equal amount of water as the base liquid for the synthesis of manganese tetroxide, and sodium dodecyl sulfonate as the surfactant. Mix the two according to the mass ratio of sodium dodecyl sulfonate:water = 6:100 and return them to the reaction vessel in S2 for precipitation oxidation.

[0062] 2) Replace S4 with S4': After aging the reaction solution for 4 hours, filter and wash thoroughly, and dry at 100°C for 6 hours to obtain battery-grade manganese tetroxide.

[0063] Other conditions, such as the selection and dosage of the remaining reagents, as well as the remaining process steps and condition parameters, are the same as in Example 3.

[0064] It is understood that this comparative example, compared to Example 3, did not undergo a densification process, and is used to demonstrate that the method of this disclosure is more effective.

[0065] The results showed that the battery-grade manganese tetroxide prepared using the method of Comparative Example 3 had a Mn content of 71.56%, a Mg content of 0.24%, and a tap density of 2.14 g / cm³. 3 .

[0066] Compare with Example 4

[0067] Comparative Example 4 and Example 3 were used. In Comparative Example 4, the low-grade manganese carbonate ore in Example 3 was used. The difference between Comparative Example 4 and Example 3 is that the overflow in S3 does not need to be mixed with sodium dodecyl sulfonate, but is directly returned to the reactor in S2 for precipitation oxidation. Other conditions, such as the selection and dosage of the remaining reagents, as well as the remaining steps and condition parameters of the process, are the same as those in Example 3.

[0068] It is understood that this comparative example, compared to Example 3, did not contain any surfactant, in order to demonstrate that the method of this disclosure is more effective.

[0069] The results showed that the battery-grade manganese tetroxide prepared using the method of Comparative Example 4 had a Mn content of 70.68%, a Mg content of 0.23%, and a tap density of 2.35 g / cm³. 3 .

[0070] Test results

[0071] To verify the effectiveness of the method for preparing battery-grade manganese tetroxide provided in this disclosure, the battery-grade manganese tetroxide prepared in Examples 1-3 and Comparative Examples 1-4 were used as precursors to prepare lithium manganese oxide cathode materials. The partial electrical performance data of the obtained lithium manganese oxide cathode materials are shown in the table below:

[0072]

[0073] The table above shows that:

[0074] 1) Battery-grade manganese tetroxide was prepared using a low-magnesium manganese sulfate solution in Comparative Examples 1 and 2, and battery-grade manganese tetroxide was prepared using a magnesium-containing manganese sulfate solution in Examples 1 and 3. Compared with Comparative Examples 1 and 2, the initial discharge performance of the lithium manganese oxide cathode material prepared by using the battery-grade manganese tetroxide of Example 3 as a precursor was slightly lower, but the cycle performance was greatly improved. In particular, the capacity retention rate of Example 3 after 50 cycles at 1C reached about 90%, while the capacity retention rate of Comparative Example 1 after 50 cycles at 1C was only 68.03%, and the capacity retention rate of Comparative Example 2 after 50 cycles at 1C was only 73.55%.

[0075] 2) No densification treatment was performed in Comparative Example 3, while Comparative Examples 1-3 underwent densification treatment. The tap density of the battery-grade manganese tetroxide prepared in Comparative Example 3 was only 2.14 g / cm³. 3 This is significantly lower than the tap density of 2.78 g / cm³ of the battery-grade manganese tetroxide prepared in Example 3. 3 Compared to Comparative Example 3, the initial discharge performance of the lithium manganese oxide cathode material prepared by using the battery-grade manganese tetroxide as a precursor in Example 3 was not significantly different, but the cycle performance was improved. Furthermore, since the tap density of the battery-grade manganese tetroxide prepared in Example 3 was significantly improved, it was more conducive to preparing lithium manganese oxide cathode materials with high volumetric energy density.

[0076] 3) No surfactant was added in Comparative Example 4, while surfactants were added in Examples 1-3. The tap density of the battery-grade manganese tetroxide prepared in Comparative Example 4 was only 2.35 g / cm³. 3The tap density is lower than the 2.78 g / cm³ of the battery-grade manganese tetroxide prepared in Example 3. 3 Compared to Comparative Example 4, the initial discharge performance and cycle performance of the lithium manganese oxide cathode material prepared by using battery-grade manganese tetroxide as a precursor in Example 3 are improved. However, since the tap density of the battery-grade manganese tetroxide prepared in Example 3 is significantly improved, it is more conducive to preparing lithium manganese oxide cathode materials with high volumetric energy density.

[0077] Therefore, the method for preparing battery-grade manganese tetroxide from low-grade manganese carbonate ore provided in this disclosure achieves the effect of directly preparing high-tap-density doped battery-grade manganese tetroxide without deep magnesium removal, and the manganese-based battery materials prepared by using it as a precursor have better charge and discharge performance.

[0078] The above description is merely a preferred embodiment of this disclosure. It should be understood that this disclosure is not limited to the forms disclosed herein and should not be construed as excluding other embodiments. It can be used in various other combinations, modifications, and environments, and can be altered within the scope of the concept described herein through the above teachings or techniques or knowledge in related fields. Any modifications and variations made by those skilled in the art that do not depart from the spirit and scope of this disclosure should be within the protection scope of the appended claims.

Claims

1. A process for the preparation of battery grade manganese sesquioxide from low grade manganese carbonate ores, characterized in that, The method comprises the following steps: carrying out sulfuric acid leaching and impurity removal on the low-grade manganese carbonate ore to obtain a magnesium-containing manganese sulfate solution; mixing the magnesium-containing manganese sulfate solution with ammonia water, and carrying out precipitation oxidation to obtain a reaction liquid; carrying out aging on the reaction liquid to obtain an aged liquid; carrying out thickening treatment on the aged liquid to obtain an overflow liquid and a bottom flow concentrated liquid; wherein the overflow liquid is returned to the precipitation oxidation after being mixed with a surfactant; and carrying out filtration, washing and drying on the bottom flow concentrated liquid to obtain the battery-grade trimanganese tetraoxide.

2. The method of claim 1, wherein, In the magnesium-containing manganese sulfate solution, the content of Mn is 60-120 g / L, and the content of Mg is 0.12-0.5 g / L.

3. The method of claim 1, wherein, Air is introduced when the precipitation oxidation is carried out.

4. The method according to claim 1 or 3, characterized in that, The pH of the precipitation oxidation is 8-10, the temperature of the precipitation oxidation is 60-90 ℃, and the time of the precipitation oxidation is 4-30 h.

5. The method of claim 1, wherein, The time of the aging is 1-4 h.

6. The method of claim 1, wherein, The surfactant comprises at least one of polyethylene glycol, sodium dodecyl sulfonate and sodium dodecyl benzene sulfonate.

7. The method according to claim 1 or 6, characterized in that, The weight ratio of the surfactant to the reaction bottom liquid is 1-6:

100.

8. The method of claim 1, wherein, The temperature of the drying is 100-200 ℃, and the time of the drying is 2-6 h.

9. The method of claim 1, wherein, In the low-grade manganese carbonate ore, the content of Mn is 10%-15%, and the content of Mg is 1%-6%.

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