A process for the production of battery grade manganese sulfate from a manganese containing solution

Abstract

The application discloses a method for preparing battery-grade manganese sulfate from a manganese-containing solution. The method comprises the following steps: performing multistage countercurrent extraction on the manganese-containing solution by using a first extractant to obtain manganese-loaded organic phase I, then performing countercurrent acid washing to obtain acid-washed organic phase I; adding sulfuric acid to perform two-stage stripping, the first-stage stripping obtaining a first-stage manganese sulfate solution and a first-stage organic phase, adding acid to the first-stage organic phase to perform second-stage stripping to obtain a second-stage manganese sulfate solution and regenerated organic phase; adding a second extractant to the first-stage manganese sulfate solution to perform countercurrent extraction to obtain manganese-loaded organic phase II, performing multistage countercurrent acid washing to obtain acid-washed organic phase II; then performing multistage countercurrent stripping to obtain a manganese sulfate solution; finally adding a copper extractant to obtain battery-grade manganese sulfate. The battery-grade manganese sulfate is prepared by using the multistage extraction technology, special impurity removal by using chemical reagents is not needed, no solid waste is discharged, and the industrial production cost can be reduced.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of manganese sulfate preparation, and particularly relates to a method for preparing battery-grade manganese sulfate from a manganese-containing solution. BACKGROUND

[0002] Battery-grade manganese sulfate is an important battery raw material, and is mainly used for the positive electrode material of batteries such as potassium ion batteries and potassium batteries. With the rapid development of emerging markets such as electric vehicles and energy storage batteries, the market demand for battery-grade manganese sulfate is also growing. At present, the battery-grade manganese sulfate industry in China is mainly concentrated in coastal areas such as Guangdong, Jiangsu and Fujian. These areas have a strong battery industry foundation and rich manganese ore resources, providing strong support for the development of the battery-grade manganese sulfate industry.

[0003] At present, a sulfuric acid solution is prepared from retired ternary lithium batteries as raw materials, and then crude manganese sulfate is obtained through extraction. Heavy metals are removed through barium sulfide, iron is removed through lime pH adjustment, and calcium and magnesium are removed through sodium fluoride. Battery-grade manganese sulfate is prepared through extraction. For the manganese oxide ore acid leaching manganese sulfate solution with many impurities, the main process is to oxidize ferrous ions with high-grade manganese oxide ore while adding ferric sulfate to precipitate potassium and sodium, neutralize iron with carbonic acid, remove calcium and magnesium with fluorination, remove heavy metals with sulfuration, and concentrate and crystallize to produce battery-grade high-purity manganese sulfate. The above method can also produce battery-grade manganese sulfate, but the process is complex, more chemical auxiliaries are needed, the industrial cost is high, and the three wastes generated in the process are serious. SUMMARY

[0004] In view of the deficiencies of the prior art, the application provides a method for preparing battery-grade manganese sulfate from a manganese-containing solution. The application prepares battery-grade manganese sulfate through three-stage extraction technology, without using chemical reagents for special impurity removal, achieving no solid waste discharge and reducing industrial production cost.

[0005] The technical scheme of the application is as follows:

[0006] The application first protects a method for preparing battery-grade manganese sulfate from a manganese-containing solution, which comprises the following steps:

[0007] S1: using a first extractant to perform multi-stage countercurrent extraction on the manganese-containing solution to obtain manganese-loaded organic phase I;

[0008] S2: using sulfuric acid to perform multi-stage countercurrent acid washing on the manganese-loaded organic phase I obtained in step S1 to obtain acid-washed organic phase I;

[0009] S3: then using sulfuric acid to perform two-stage stripping on the acid-washed organic phase I, using multi-stage countercurrent stripping to obtain a first-stage manganese sulfate solution and a first-stage organic phase, and then using sulfuric acid to perform second-stage stripping on the first-stage organic phase by adding sulfuric acid to obtain a second-stage manganese sulfate solution and a regenerated organic phase;

[0010] S4: then the first-stage manganese sulfate solution obtained in step S3 is subjected to multi-stage countercurrent extraction with a second extractant to obtain manganese-loaded organic phase II,

[0011] S5: the manganese-loaded organic phase II obtained in step S4 is subjected to multi-stage countercurrent acid washing with sulfuric acid to obtain acid-washed organic phase II;

[0012] S6: the acid-washed organic phase II is subjected to multi-stage countercurrent stripping with sulfuric acid to obtain a manganese sulfate solution;

[0013] S7: finally, the manganese sulfate solution obtained in step S6 is subjected to countercurrent extraction with a copper extractant to obtain a raffinate which is a battery-grade manganese sulfate.

[0014] Preferably, the first extractant is saponified di(2-ethylhexyl) phosphate; and the second extractant is saponified di(2,4,4-trimethylpentyl) phosphinic acid.

[0015] Preferably, the saponified di(2-ethylhexyl) phosphate is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, and the volume fraction of di(2-ethylhexyl) phosphate in the saponified di(2-ethylhexyl) phosphate is 20%-25%; and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%-45%.

[0016] Preferably, the pH value of the manganese-containing solution is 4-5.

[0017] Preferably, the multi-stage countercurrent extraction is 5-stage countercurrent extraction, each stage is mixed for 3-5 min at a volume ratio of the first extractant to the manganese-containing solution of 1-3:1, and then is allowed to stand for 10-15 min to separate into layers to obtain the manganese-loaded organic phase I.

[0018] Preferably, in step S2, the concentration of the sulfuric acid is 0.1-0.3 mol / L; and the multi-stage countercurrent acid washing is 3-stage countercurrent acid washing, each stage is mixed for 3-5 min at a volume ratio of the manganese-loaded organic phase I to the sulfuric acid of 5:1, and then is allowed to stand for 10-15 min to separate into layers to obtain the acid-washed organic phase I.

[0019] Preferably, in step S3, the concentration of the sulfuric acid is 2-2.5 mol / L; the first-stage stripping is specifically as follows: 5-stage countercurrent stripping is adopted, each stage is mixed for 3-5 min according to the volume ratio of the pickling organic phase I to the sulfuric acid being 16-17:1, then is allowed to stand for 10-15 min to be layered to obtain a first-stage manganese sulfate solution and a first-stage organic phase; the content of manganese ions in the first-stage manganese sulfate solution accounts for 70-90% of the content of manganese ions in the manganese-loaded organic phase I, and the pH value is 3.5-4; the second-stage stripping is specifically as follows: 3-stage countercurrent stripping is adopted, each stage is mixed for 3-5 min according to the volume ratio of the first-stage organic phase to the sulfuric acid being 16-17:1, then is allowed to stand for 10-15 min to be layered to obtain a second-stage manganese sulfate solution and a regenerated organic phase.

[0020] Preferably, in step S4, the multi-stage countercurrent extraction is 5-stage countercurrent extraction, each stage is mixed for 3-5 min according to the volume ratio of the second extractant to the first-stage manganese sulfate solution being 20-21:1, then is allowed to stand for 10-15 min to be layered to obtain the manganese-loaded organic phase II.

[0021] Preferably, the saponified bis(2,4,4-trimethylpentyl) phosphinic acid is configured from bis(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, the volume fraction of the bis(2,4,4-trimethylpentyl) phosphinic acid in the bis(2,4,4-trimethylpentyl) phosphinic acid is 15-20%, and the saponification rate of the saponified bis(2,4,4-trimethylpentyl) phosphinic acid is 40%-45%.

[0022] Preferably, in step S5, the concentration of the sulfuric acid is 0.1-0.3 mol / L; the multi-stage countercurrent pickling is 3-stage countercurrent pickling, each stage is mixed for 3-5 min according to the volume ratio of the manganese-loaded organic phase II to the sulfuric acid being 5:1, then is allowed to stand for 10-15 min to be layered to obtain the pickling organic phase II.

[0023] Preferably, in step S6, the concentration of the sulfuric acid is 2-2.5 mol / L, and the multi-stage countercurrent stripping is 6-stage countercurrent stripping, each stage is mixed for 3-5 min according to the volume ratio of the pickling organic phase II to the sulfuric acid being 16-17:1, then is allowed to stand for 10-15 min to be layered to obtain the manganese sulfate solution.

[0024] Preferably, in step S7, the countercurrent extraction is 2-stage countercurrent extraction, each stage is mixed for 3-5 min according to the volume ratio of the copper catalyst to the manganese sulfate solution being 2-3:1, then is allowed to stand for 10-15 min to be layered, and the raffinate obtained is the battery-grade manganese sulfate solution.

[0025] The application has the beneficial technical effects that:

[0026] The present application realizes efficient separation of manganese and impurities by first washing away difficult-to-extract impurities with acid after extracting manganese with saponified di(2-ethylhexyl) phosphate extractant, and then shaking off easy-to-extract impurities by two-stage stripping of manganese in the organic phase, and then obtaining battery-grade manganese sulfate by purifying and removing copper from the first-stage manganese sulfate through di(2,4,4-trimethylpentyl) phosphinic acid extractant and copper extractant.

[0027] The present application realizes efficient separation of manganese and impurities by first washing away difficult-to-extract impurities with acid after extracting manganese with saponified di(2-ethylhexyl) phosphate extractant, and then shaking off easy-to-extract impurities by two-stage stripping of manganese in the organic phase, and then obtaining battery-grade manganese sulfate by purifying and removing copper from the first-stage manganese sulfate through di(2,4,4-trimethylpentyl) phosphinic acid extractant and copper extractant. BRIEF DESCRIPTION OF DRAWINGS

[0028] Figure 1 Figure 1 is a diagram of the relationship between the sequence of di(2-ethylhexyl) phosphate extraction of metals and the pH of the aqueous phase.

[0029] Figure 2 Figure 2 is a process flow diagram of the present application. DETAILED DESCRIPTION

[0030] The present application will be specifically described below in combination with the drawings and examples.

[0031] The present application first provides a method for preparing battery-grade manganese sulfate from a manganese-containing solution, which comprises the following steps:

[0032] S1: multi-stage countercurrent extraction of the manganese-containing solution with a first extractant to obtain manganese-loaded organic phase I;

[0033] S2: multi-stage countercurrent acid washing of the manganese-loaded organic phase I obtained in step S1 with sulfuric acid to obtain acid-washed organic phase I;

[0034] S3: two-stage stripping of the acid-washed organic phase I with sulfuric acid, wherein the first-stage stripping is carried out by multi-stage countercurrent stripping to obtain first-stage manganese sulfate solution and first-stage organic phase, and then the first-stage organic phase is subjected to second-stage stripping with sulfuric acid to obtain second-stage manganese sulfate solution and regenerated organic phase;

[0035] S4: multi-stage countercurrent extraction of the first-stage manganese sulfate solution obtained in step S3 with a second extractant to obtain manganese-loaded organic phase II,

[0036] S5: multi-stage countercurrent acid washing of the manganese-loaded organic phase II obtained in step S4 with sulfuric acid to obtain acid-washed organic phase II;

[0037] S6: multi-stage countercurrent stripping of the acid-washed organic phase II with sulfuric acid to obtain manganese sulfate solution;

[0038] S7: countercurrent extraction of the manganese sulfate solution of step S6 with a copper extractant to obtain raffinate which is battery-grade manganese sulfate;

[0039] The first extractant is saponified di(2-ethylhexyl) phosphate; the second extractant is saponified di(2,4,4-trimethylpentyl) phosphinic acid.

[0040] In some embodiments of the present application, the saponified di(2-ethylhexyl) phosphate is configured by di(2-ethylhexyl) phosphate and sulfonated kerosene, the volume fraction of di(2-ethylhexyl) phosphate in the saponified di(2-ethylhexyl) phosphate is 20%-25%; the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%-45%.

[0041] In some embodiments of the present application, the di(2,4,4-trimethylpentyl) phosphinic acid is configured by di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, the volume fraction of di(2,4,4-trimethylpentyl) phosphinic acid in the di(2,4,4-trimethylpentyl) phosphinic acid is 15-20%; the saponification rate of the saponified di(2,4,4-trimethylpentyl) phosphinic acid is 40%-45%.

[0042] In some embodiments of the present application, the sulfonated kerosene is 260# sulfonated kerosene.

[0043] In some embodiments of the present application, the saponified di(2-ethylhexyl) phosphate is obtained by mixing di(2-ethylhexyl) phosphate and 260# sulfonated kerosene. The di(2,4,4-trimethylpentyl) phosphinic acid is obtained by mixing di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene.

[0044] It can be understood that the first extractant of the present application contains hydroxyl, and by limiting the saponification rate, the extraction effect is improved. The second extractant of the present application contains hydroxyl, and the extraction rate of manganese in the extraction can be higher.

[0045] In the present application, the saponification rate of di(2-ethylhexyl) phosphate and di(2,4,4-trimethylpentyl) phosphinic acid extractant cannot exceed 50%. It can be understood that if the saponification rate exceeds this range, a third phase will be generated between the extractant and the feed liquid, affecting the separation and extraction efficiency.

[0046] In some embodiments of the present application, in step S1, the manganese-containing solution is prepared by mixing positive and negative mixed black powder of retired ternary lithium batteries, and using sulfuric acid and hydrogen peroxide as reducing agents for leaching. The leaching solution is subjected to preliminary copper removal by iron powder, and then subjected to preliminary iron and aluminum removal by sodium carbonate to obtain a manganese-containing sulfuric acid solution. The manganese-containing solution contains the following elements: manganese ions 7.56 g / L, copper ions 0.21 g / L, zinc ions 0.45 g / L, calcium ions 0.23 g / L, and iron ions 0.05 g / L. The pH value of the manganese-containing solution is 4-5.

[0047] It can be understood that in the present application, the pH of the original feed liquid cannot be less than 3, and when less than 3, the extraction efficiency will be significantly reduced.

[0048] In some embodiments of the present application, in step S1, the multi-stage countercurrent extraction is 5-stage countercurrent extraction, each stage is mixed with the first extractant and the manganese-containing solution at a volume ratio of 1-3:1 for 3-5 min, and is allowed to stand for 10-15 min to separate the layers to obtain the manganese-loaded organic phase I.

[0049] It can be understood that the manganese-loaded organic phase I contains manganese ions, copper ions, zinc ions, calcium ions, iron ions, and through step S1, cobalt, nickel, sodium ions and the like which cannot be loaded in the organic phase can be removed.

[0050] In some embodiments of the present application, in step S2, the concentration of the sulfuric acid is 0.1-0.3 mol / L; and the multi-stage countercurrent acid washing refers to 3-stage countercurrent acid washing, each stage is mixed with the manganese-loaded organic phase I and sulfuric acid at a volume ratio of 5:1 for 3-5 min, and is allowed to stand for 10-15 min to separate the layers to obtain the acid-washed organic phase I.

[0051] It can be understood that in step S2, by adding acid for countercurrent acid washing, the impurity ions cobalt and nickel in the manganese-loaded organic phase I are removed to obtain the acid-washed organic phase I containing manganese and zinc, calcium and iron ions.

[0052] In some embodiments of the present application, in step S3, the concentration of the sulfuric acid is 2-2.5 mol / L.

[0053] In some embodiments of the present application, in step S3, the first-stage stripping is specifically: 5-stage countercurrent stripping is adopted, each stage is mixed with the acid-washed organic phase I and sulfuric acid at a volume ratio of 16-17:1 for 3-5 min, and is allowed to stand for 10-15 min to separate the layers to obtain the first-stage manganese sulfate solution and the first-stage organic phase; wherein the content of manganese ions in the first-stage manganese sulfate solution accounts for 70-90% of the content of manganese ions in the manganese-loaded organic phase I, and the pH value is 3.5-4.

[0054] It can be understood that in the first-stage stripping of the present application, the content of manganese in the bis(2-ethylhexyl) phosphate extractant cannot exceed 90% of the total manganese in the organic phase, and when it exceeds 90%, the impurities in the first-stage manganese sulfate solution will exceed the standard.

[0055] In some embodiments of the present application, in step S3, the second-stage stripping is specifically: 3-stage countercurrent stripping is adopted, each stage is mixed with the first-stage organic phase and sulfuric acid at a volume ratio of 16-17:1 for 3-5 min, and is allowed to stand for 10-15 min to separate the layers to obtain the second-stage manganese sulfate solution and the regenerated organic phase. In this step, the manganese content of the second-stage manganese sulfate solution is low, and the impurities such as calcium and zinc are high.

[0056] It can be understood that step S3 obtains manganese sulfate solution mainly containing manganese ions and a small amount of other metal ions and an organic phase containing metal ions such as calcium, iron, zinc and copper by first stripping, and the organic phase is subjected to second stripping to obtain second manganese sulfate solution containing the above impurity ions and the organic phase which can be recycled.

[0057] In some embodiments of the present application, in step S4, the multi-stage countercurrent extraction is 5-stage countercurrent extraction, each stage is mixed for 3-5 min at a volume ratio of the second extractant to the first manganese sulfate solution of 20-21:1, and then is allowed to stand for 10-15 min to separate into layers to obtain manganese-loaded organic phase II.

[0058] It can be understood that step S4 removes impurity metal ions in the first manganese sulfate solution by adding a second extractant to obtain an organic phase containing copper ions and manganese ions.

[0059] In some embodiments of the present application, in step S5, the concentration of the sulfuric acid is 0.1-0.3 mol / L; and the multi-stage countercurrent acid washing is 3-stage countercurrent acid washing, each stage is mixed for 3-5 min at a volume ratio of the manganese-loaded organic phase II to the sulfuric acid of 5:1, and then is allowed to stand for 10-15 min to separate into layers to obtain acid-washed organic phase II.

[0060] It can be understood that step S5 removes impurity ions dissolved in acid, i.e., sodium, cobalt, calcium, nickel and the like, by acid washing to obtain an organic phase containing copper ions and manganese ions.

[0061] In some embodiments of the present application, in step S6, the concentration of the sulfuric acid is 2-2.5 mol / L, and the multi-stage countercurrent stripping is 6-stage countercurrent stripping, each stage is mixed for 3-5 min at a volume ratio of the acid-washed organic phase II to the sulfuric acid of 16-17:1, and then is allowed to stand for 10-15 min to separate into layers to obtain manganese sulfate solution.

[0062] It can be understood that step S6 obtains manganese sulfate solution containing manganese ions and copper ions by stripping.

[0063] In some embodiments of the present application, in step S7, the countercurrent extraction is 2-stage countercurrent extraction, each stage is mixed for 3-5 min at a volume ratio of the copper catalyst to the manganese sulfate solution of 2-3:1, and then is allowed to stand for 10-15 min to separate into layers, and the raffinate obtained is battery-grade manganese sulfate solution.

[0064] It can be understood that step S7 removes copper ions by adding a copper extractant to obtain battery-grade manganese sulfate solution; the content of manganese ions in the battery-grade manganese sulfate solution can reach 100-110 g / L; and the content of the remaining metal ions is lower than 0.008 g / L.

[0065] It can be understood that the mixing time of the organic phase and the aqueous phase in the present application cannot be less than 3 minutes, and the standing time cannot be less than 10 minutes. Too short mixing time will cause incomplete extraction reaction, and too long mixing time will not affect the extraction reaction, but will delay the efficiency.

[0066] The present application is further illustrated by examples.

[0067] Example 1:

[0068] (1) The manganese in the manganese-containing solution was extracted by 5-stage countercurrent extraction with saponified di(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 1:1 for 5 minutes, and then separated into an organic phase loaded with manganese after standing for 10 minutes. The pH of the manganese-containing solution was 4-5. The di(2-ethylhexyl) phosphate extractant was configured from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume ratio of di(2-ethylhexyl) phosphate was 20%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant was 35%;

[0069] (2) The impurities in the loaded organic phase of step (1) were subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at a volume ratio of organic to sulfuric acid of 5:1 for 3 minutes, and then separated into an organic phase after standing for 10 minutes. Then, the organic phase was subjected to two-stage stripping with 2 mol / L sulfuric acid. The first stage was 5-stage countercurrent stripping, mixed at a volume ratio of organic to sulfuric acid of 16:1 for 3 minutes, and then separated into a first-stage manganese sulfate solution and an organic phase after standing for 10 minutes. The manganese content in the first-stage manganese sulfate solution accounted for 70% of the manganese in the loaded organic phase, and the calcium and zinc impurities were low, with a pH of 3.5-4. The second stage was 3-stage countercurrent stripping, mixed at a volume ratio of organic to sulfuric acid of 16:1 for 3 minutes, and then separated into a second-stage manganese sulfate solution and a regenerated organic phase after standing for 10 minutes. The manganese content in the second-stage manganese sulfate solution was low, and the calcium and zinc impurities were high.

[0070] (3) The first-stage manganese sulfate solution was subjected to 5-stage countercurrent extraction with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 20:1 for 3 minutes, and then separated into a manganese-loaded organic phase after standing for 10 minutes. The di(2,4,4-trimethylpentyl) phosphinic acid extractant was configured from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, wherein the volume ratio of di(2,4,4-trimethylpentyl) phosphinic acid was 15%, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant was 40%.

[0071] (4) The impurities in the loaded organic phase in step (3) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at an organic phase to sulfuric acid volume ratio of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain the organic phase, and then the organic is subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at an organic phase to sulfuric acid volume ratio of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese sulfate solution;

[0072] (5) The manganese sulfate solution obtained in step (4) is subjected to 2-stage countercurrent extraction of copper with a copper extractant, mixed at an extractant to manganese sulfate solution volume ratio of 2:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain the raffinate, which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0073] Example 2:

[0074] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with a saponified di(2-ethylhexyl) phosphate extractant, mixed at an extractant to manganese-containing solution volume ratio of 3:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into layers to obtain a manganese-loaded organic phase, the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is configured from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume ratio of di(2-ethylhexyl) phosphate is 25%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 45%;

[0075] (2) The impurities in the loaded organic phase in step (1) are subjected to 3-stage countercurrent acid washing with 0.3 mol / L sulfuric acid, mixed at an organic to sulfuric acid volume ratio of 5:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into layers to obtain the organic phase, and then the organic is subjected to two-stage stripping with 2.5 mol / L sulfuric acid, the first stage is 5-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 17:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into layers to obtain the first-stage manganese sulfate solution and the organic phase, the manganese content in the first-stage manganese sulfate solution accounts for 90% of the manganese in the loaded organic phase and the content of calcium, zinc and other impurities is low, and the pH is 3.5-4, the second stage is 3-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 17:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into layers to obtain the second-stage manganese sulfate solution and the regenerated organic phase, the manganese content in the second-stage manganese sulfate solution is low and the content of calcium, zinc and other impurities is high;

[0076] (3) The manganese sulfate solution of the first paragraph is subjected to 5-stage countercurrent extraction of manganese with saponified bis(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 21:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into a manganese-loaded organic phase, the bis(2,4,4-trimethylpentyl) phosphinic acid extractant being configured from bis(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, with the volume ratio of bis(2,4,4-trimethylpentyl) phosphinic acid being 20%, and the saponification rate of the bis(2,4,4-trimethylpentyl) phosphinic acid extractant being 45%;

[0077] (4) The impurities in the loaded organic phase in step (3) are subjected to 3-stage countercurrent acid washing with 0.3 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 5:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into an organic phase, and then subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 17:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into a manganese sulfate solution;

[0078] (5) The manganese sulfate solution obtained in step (4) is subjected to 2-stage countercurrent extraction of copper with a copper extractant, mixed at a volume ratio of extractant to manganese sulfate solution of 3:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into a raffinate which is a battery-grade manganese sulfate, wherein the content of each element (g / L) is as shown in Table 1.

[0079] Example 3:

[0080] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with saponified bis(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 2:1 for 4 minutes, and then allowed to stand for 13 minutes to separate into a manganese-loaded organic phase, the pH of the manganese-containing solution being 4-5, the bis(2-ethylhexyl) phosphate extractant being configured from bis(2-ethylhexyl) phosphate and 260# sulfonated kerosene, with the volume ratio of bis(2-ethylhexyl) phosphate being 25%, and the saponification rate of the bis(2-ethylhexyl) phosphate extractant being 40%;

[0081] (2) The impurities in the loaded organic phase of step (1) are washed with 0.2 mol / L sulfuric acid by 3-stage countercurrent acid washing, mixed at an organic to sulfuric acid volume ratio of 5:1 for 4 minutes, then separated into layers for 13 minutes to obtain the organic phase, then the organic is stripped with 2.5 mol / L sulfuric acid in two stages, the first stage uses 5-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 17:1 for 4 minutes, then separated into layers for 13 minutes to obtain the first-stage manganese sulfate solution and the organic phase, the manganese content of the first-stage manganese sulfate solution accounts for 80% of the manganese in the loaded organic phase, and the calcium, zinc and other impurities are low, PH = 3.5-4, the second stage uses 3-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 17:1 for 4 minutes, then separated into layers for 13 minutes to obtain the second-stage manganese sulfate solution and the regenerated organic phase, the manganese content of the second-stage manganese sulfate solution is low and the calcium, zinc and other impurities are high;

[0082] (3) The first-stage manganese sulfate solution is extracted with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant by 5-stage countercurrent extraction, mixed at an extractant to manganese-containing solution volume ratio of 21:1 for 4 minutes, then separated into layers for 13 minutes to obtain the loaded manganese organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant is prepared from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, wherein the di(2,4,4-trimethylpentyl) phosphinic acid accounts for 20% by volume, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant is 45%;

[0083] (4) The impurities in the loaded organic phase of step (3) are washed with 0.2 mol / L sulfuric acid by 3-stage countercurrent acid washing, mixed at an organic to sulfuric acid volume ratio of 5:1 for 4 minutes, then separated into layers for 13 minutes to obtain the organic phase, then the organic is stripped with 2 mol / L sulfuric acid by 6-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 17:1 for 4 minutes, then separated into layers for 13 minutes to obtain the manganese sulfate solution;

[0084] (5) The manganese sulfate solution obtained in step (4) is extracted with copper extractant by 2-stage countercurrent extraction, mixed at an extractant to manganese sulfate solution volume ratio of 3:1 for 4 minutes, then separated into layers for 13 minutes to obtain the raffinate, which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0085] Comparative Example 1:

[0086] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with a saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant, the extractant and the manganese-containing solution are mixed at a volume ratio of 21:1 for 5 minutes, and then are allowed to stand for 15 minutes to separate into a manganese-loaded organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant is prepared from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, wherein the volume ratio of di(2,4,4-trimethylpentyl) phosphinic acid is 20%, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant is 45%;

[0087] (2) The impurities in the loaded organic phase in step (1) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, the organic phase and the sulfuric acid are mixed at a volume ratio of 5:1 for 5 minutes, and then are allowed to stand for 15 minutes to separate into an organic phase, and then the organic phase is subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, the organic phase and the sulfuric acid are mixed at a volume ratio of 17:1 for 5 minutes, and then are allowed to stand for 15 minutes to separate into a manganese sulfate solution;

[0088] (3) The manganese sulfate solution obtained in step (3) is subjected to 2-stage countercurrent extraction with a copper extractant, the extractant and the manganese sulfate solution are mixed at a volume ratio of 3:1 for 5 minutes, and then are allowed to stand for 15 minutes to separate into a raffinate, which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0089] Comparative Example 2:

[0090] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with a saponified di(2-ethylhexyl) phosphate extractant, the extractant and the manganese-containing solution are mixed at a volume ratio of 1:1 for 5 minutes, and then are allowed to stand for 10 minutes to separate into a manganese-loaded organic phase, the pH of the manganese-containing solution is 4-5, the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume ratio of di(2-ethylhexyl) phosphate is 20%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%;

[0091] (2) The impurities in the loaded organic phase in step (1) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, the organic and the sulfuric acid are mixed at a volume ratio of 5:1 for 3 minutes, and then are allowed to stand for 10 minutes to separate into an organic phase, and then the organic is subjected to one-stage stripping with 2 mol / L sulfuric acid, the organic and the sulfuric acid are mixed at a volume ratio of 15:1 for 3 minutes, and then are allowed to stand for 10 minutes to separate into a manganese sulfate solution and an organic phase, the manganese content in the manganese sulfate solution accounts for 100% of the manganese in the loaded organic phase, and the pH is 1.5-2.

[0092] (3) Step (2) is subjected to 5-stage countercurrent extraction of manganese with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant being configured from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, with the di(2,4,4-trimethylpentyl) phosphinic acid accounting for 15% by volume, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant being 40%;

[0093] (4) The impurities in the loaded organic phase in step (3) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into an organic phase, which is then subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese sulfate solution;

[0094] (5) The manganese sulfate solution obtained in step (4) is subjected to 2-stage countercurrent extraction of copper with copper extractant, mixed at a volume ratio of extractant to manganese sulfate solution of 2:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a raffinate which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0095] Comparative Example 3:

[0096] The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with saponified di(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 1:1 for 5 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase, the pH of the manganese-containing solution being 4-5, the di(2-ethylhexyl) phosphate extractant being configured from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, with the di(2-ethylhexyl) phosphate accounting for 20% by volume, and the saponification rate of the di(2-ethylhexyl) phosphate extractant being 35%;

[0097] (2) The impurities in the loaded organic phase in step (1) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at a volume ratio of organic to sulfuric acid of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into an organic phase, which is then subjected to one-stage stripping with 2 mol / L sulfuric acid, mixed at a volume ratio of organic to sulfuric acid of 15:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese sulfate solution and an organic phase, the manganese content in the manganese sulfate solution accounting for 100% of the manganese in the loaded organic phase, and the pH being 1.5-2;

[0098] (3) The manganese sulfate solution in step (2) is added with 2 times the total molar amount of copper and zinc to barium sulfide, allowed to react for 1 hour, and then filtered to obtain a filtrate;

[0099] (4) The filtrate in step (3) is subjected to 5-stage countercurrent extraction of manganese with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant being configured from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, with the di(2,4,4-trimethylpentyl) phosphinic acid accounting for 15% by volume, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant being 40%;

[0100] (5) The impurities in the loaded organic phase in step (4) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into an organic phase, which is then subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a battery-grade manganese sulfate solution, wherein the content of each element (g / L) is shown in Table 1.

[0101] Comparative Example 4:

[0102] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with saponified di(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 1:1 for 5 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase, the pH of the manganese-containing solution being 4-5, the di(2-ethylhexyl) phosphate extractant being configured from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, with the di(2-ethylhexyl) phosphate accounting for 20% by volume, and the saponification rate of the di(2-ethylhexyl) phosphate extractant being 35%;

[0103] (2) The impurities in the loaded organic phase in step (1) are subjected to 3-stage countercurrent acid washing with 0.4 mol / L sulfuric acid, mixed at a volume ratio of organic to sulfuric acid of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into an organic phase, which is then subjected to two-stage stripping with 2 mol / L sulfuric acid, the first stage being 5-stage countercurrent stripping, mixed at a volume ratio of organic to sulfuric acid of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a first-stage manganese sulfate solution and an organic phase, the manganese content of the first-stage manganese sulfate solution being 70% of the manganese in the loaded organic phase, the pH being 3.5-4, the second stage being 3-stage countercurrent stripping, mixed at a volume ratio of organic to sulfuric acid of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a second-stage manganese sulfate solution and a regenerated organic phase, the manganese content of the second-stage manganese sulfate solution being low and the impurities such as calcium and zinc being high;

[0104] (3) The manganese sulfate solution of the first section is subjected to 5-stage countercurrent extraction of manganese with saponified bis(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase; the bis(2,4,4-trimethylpentyl) phosphinic acid extractant is configured from bis(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, with the volume ratio of bis(2,4,4-trimethylpentyl) phosphinic acid being 15%, and the saponification rate of the bis(2,4,4-trimethylpentyl) phosphinic acid extractant being 40%;

[0105] (4) The impurities in the loaded organic phase in step (3) are subjected to 3-stage countercurrent acid washing with 0.4 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into an organic phase, which is then subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at a volume ratio of organic phase to sulfuric acid of 16:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a manganese sulfate solution;

[0106] (5) The manganese sulfate solution obtained in step (4) is subjected to 2-stage countercurrent extraction of copper with a copper extractant, mixed at a volume ratio of extractant to manganese sulfate solution of 2:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into a raffinate, which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0107] Comparative Example 5:

[0108] (1) The manganese in the manganese-containing solution is subjected to 5-stage countercurrent extraction with saponified bis(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 1:1 for 5 minutes, and then allowed to stand for 10 minutes to separate into a manganese-loaded organic phase; the pH of the manganese-containing solution is 4-5; the bis(2-ethylhexyl) phosphate extractant is configured from bis(2-ethylhexyl) phosphate and 260# sulfonated kerosene, with the volume ratio of bis(2-ethylhexyl) phosphate being 20%, and the saponification rate of the bis(2-ethylhexyl) phosphate extractant being 55%;

[0109] (2) The impurities in the loaded organic phase of step (1) are washed with 0.1 mol / L sulfuric acid by 3-stage countercurrent acid washing, mixed at an organic to sulfuric acid volume ratio of 5:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the organic phase, then the organic is stripped with 2 mol / l sulfuric acid in two stages, the first stage uses 5-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 16:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the first-stage manganese sulfate solution and the organic phase, the manganese content in the first-stage manganese sulfate solution accounts for 70% of the manganese in the loaded organic phase, PH = 3.5-4, the second stage uses 3-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 16:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the second-stage manganese sulfate solution and the regenerated organic phase, the manganese content in the second-stage manganese sulfate solution is low and the impurities such as calcium and zinc are high;

[0110] (3) The first-stage manganese sulfate solution is extracted with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant by 5-stage countercurrent extraction, mixed at an extractant to manganese-containing solution volume ratio of 20:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the loaded manganese organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant is configured from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, wherein the di(2,4,4-trimethylpentyl) phosphinic acid volume ratio is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant is 55%;

[0111] (4) The impurities in the loaded organic phase of step (3) are washed with 0.1 mol / L sulfuric acid by 3-stage countercurrent acid washing, mixed at an organic to sulfuric acid volume ratio of 5:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the organic phase, then the organic is stripped with 2 mol / l sulfuric acid in 6-stage countercurrent stripping, mixed at an organic to sulfuric acid volume ratio of 16:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the manganese sulfate solution;

[0112] (5) The manganese sulfate solution obtained in step (4) is extracted with copper extractant by 2-stage countercurrent extraction, mixed at an extractant to manganese sulfate solution volume ratio of 2:1 for 3 minutes, then allowed to stand for 10 minutes to separate the layers to obtain the raffinate, which is the battery-grade manganese sulfate, wherein the content of each element (g / L) is shown in Table 1.

[0113] Comparative Example 6:

[0114] (1) Manganese in the manganese-containing solution is extracted by 5-stage countercurrent extraction with saponified di(2-ethylhexyl) phosphate extractant, mixed at a volume ratio of extractant to manganese-containing solution of 1:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a manganese-loaded organic phase, the manganese-containing solution has a pH of 4-5, and the di(2-ethylhexyl) phosphate extractant is configured from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the di(2-ethylhexyl) phosphate accounts for 20% by volume, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%;

[0115] (2) The impurities in the loaded organic phase of step (1) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at an organic phase to sulfuric acid volume ratio of 5:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into an organic phase, and then the organic phase is subjected to two-stage stripping with 2 mol / L sulfuric acid, the first stage is 5-stage countercurrent stripping, mixed at an organic phase to sulfuric acid volume ratio of 16:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a first-stage manganese sulfate solution and an organic phase, the manganese content in the first-stage manganese sulfate solution accounts for 70% of the manganese in the loaded organic phase, and the pH is 3.5-4, the second stage is 3-stage countercurrent stripping, mixed at an organic phase to sulfuric acid volume ratio of 16:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a second-stage manganese sulfate solution and a regenerated organic phase, and the manganese content in the second-stage manganese sulfate solution is low and the impurities such as calcium and zinc are high;

[0116] (3) The first-stage manganese sulfate solution is subjected to 5-stage countercurrent extraction of manganese with saponified di(2,4,4-trimethylpentyl) phosphinic acid extractant, mixed at a volume ratio of extractant to manganese-containing solution of 20:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a manganese-loaded organic phase, the di(2,4,4-trimethylpentyl) phosphinic acid extractant is configured from di(2,4,4-trimethylpentyl) phosphinic acid and 260# sulfonated kerosene, wherein the di(2,4,4-trimethylpentyl) phosphinic acid accounts for 15% by volume, and the saponification rate of the di(2,4,4-trimethylpentyl) phosphinic acid extractant is 40%;

[0117] (4) The impurities in the loaded organic phase of step (3) are subjected to 3-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at an organic phase to sulfuric acid volume ratio of 5:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into an organic phase, and then the organic phase is subjected to 6-stage countercurrent stripping with 2 mol / L sulfuric acid, mixed at an organic phase to sulfuric acid volume ratio of 16:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a manganese sulfate solution;

[0118] (5) The manganese sulfate solution obtained in step (4) is subjected to 2-stage countercurrent extraction of copper with copper extractant, mixed at a volume ratio of extractant to manganese sulfate solution of 2:1 for 2 minutes, and then allowed to stand for 8 minutes to separate into a raffinate which is a battery-grade manganese sulfate, wherein the contents of various elements (g / L) are shown in Table 1.

[0119] Table 1: Element content in sulfuric acid solution in examples and comparative examples

[0120]

[0121] From Table 1, it can be seen that the comparative example 1 does not use the saponified di(2-ethylhexyl) phosphate extractant and the corresponding steps (1), (2), at this time the zinc ion and calcium ion content is significantly increased. The comparative example 2 only carries out one extraction, and the obtained battery-grade manganese sulfate solution has a high calcium ion content. The comparative example 3 only carries out one stripping, and does not use copper extractant, and the obtained battery-grade manganese sulfate solution has a high copper ion and calcium ion content. The comparative example 4 changes the concentration of sulfuric acid in steps (2), (4), and the obtained calcium ion concentration is significantly increased. The comparative example 5 changes the saponification rate of the extractant, and the zinc ion content is high. The comparative example 6 changes the mixing and standing time, and the obtained solution has a low manganese ion content, and the copper ion and zinc ion contents are significantly increased. The examples of the present application obtain a high manganese ion content and a low content of other ions in the sulfuric acid solution by limiting the extraction process and the parameters of each stage.

[0122] The above is only the preferred embodiment of the present application, and the present application is not limited to the above examples. It can be understood that other improvements and changes directly derived or thought of by those skilled in the art without departing from the spirit and concept of the present application should be considered to be included in the protection scope of the present application.

Claims

1. A method for preparing battery-grade manganese sulfate from a manganese-containing solution, characterized in that: The method comprises the following steps: S1: using a first extractant to perform multi-stage countercurrent extraction on the manganese-containing solution to obtain a manganese-loaded organic phase I; S2: performing multi-stage countercurrent acid washing on the manganese-loaded organic phase I obtained in step S1 with sulfuric acid to obtain an acid-washed organic phase I; S3: The acid-washed organic phase I is then subjected to two-stage back extraction with sulfuric acid. The first stage of back extraction uses multi-stage countercurrent back extraction to obtain a first stage of manganese sulfate solution and a first stage of organic phase. The first stage of organic phase is then subjected to a second stage of back extraction with sulfuric acid to obtain a second stage of manganese sulfate solution and a regenerated organic phase. S4: The first manganese sulfate solution obtained in step S3 is then subjected to multi-stage countercurrent extraction using a second extractant to obtain an organic phase II loaded with manganese. S5: performing multi-stage countercurrent acid washing on the manganese-loaded organic phase II obtained in step S4 using sulfuric acid to obtain an acid-washed organic phase II; S6: The acid-washed organic phase II is subjected to multi-stage countercurrent stripping again with sulfuric acid to obtain a manganese sulfate solution; S7: Finally, the manganese sulfate solution in step S6 is subjected to countercurrent extraction with a copper extractant to obtain a raffinate which is battery-grade manganese sulfate; The first extractant is saponified di(2-ethylhexyl) phosphate; The second extractant is saponified di(2,4,4-trimethylpentyl)phosphinic acid; The saponification rate of the first extractant is 35-45%; In step S1, the pH value of the manganese-containing solution is 4-5; in the multi-stage countercurrent extraction, the first extractant of each stage is mixed with the manganese-containing solution for 3-5 minutes, and allowed to stand for 10-15 minutes to separate layers, thereby obtaining a manganese-loaded organic phase I; In step S2, the concentration of the sulfuric acid is 0.1-0.3 mol / L; in the multi-stage countercurrent pickling, the manganese-loaded organic phase I is mixed with sulfuric acid for 3-5 minutes in each stage, and allowed to stand for 10-15 minutes to separate layers, thereby obtaining the pickled organic phase I; In step S3, in the first stage of stripping, after each stage of the acid-washed organic phase I is mixed with sulfuric acid for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining a first stage of manganese sulfate solution and a first stage of organic phase; the manganese ion content in the first stage of the manganese sulfate solution accounts for 70-90% of the manganese ion content in the manganese-loaded organic phase I, and the pH value is 3.5-4; the second stage of stripping adopts three-stage countercurrent stripping, after each stage of the first stage of the organic phase is mixed with sulfuric acid for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining a second stage of manganese sulfate solution and a regenerated organic phase; In step S4, in the multi-stage countercurrent extraction, the second extractant of each stage is mixed with the first stage manganese sulfate solution for 3-5 minutes, and then allowed to stand for 10-15 minutes to separate the layers, thereby obtaining a manganese-loaded organic phase II; The saponification rate of the second extractant is 40% to 45%; In step S5, in the multi-stage countercurrent pickling, the organic phase II loaded with manganese in each stage is mixed with sulfuric acid for 3-5 minutes, and then allowed to stand for 10-15 minutes to separate layers, thereby obtaining the pickled organic phase II; In step S6, in the multi-stage countercurrent stripping, the acid-washed organic phase II of each stage is mixed with sulfuric acid for 3-5 minutes, and then allowed to stand for 10-15 minutes to separate the layers, thereby obtaining a manganese sulfate solution; In step S7, the countercurrent extraction is a two-stage countercurrent extraction. After each stage of the copper extractant and the manganese sulfate solution are mixed for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate the layers. The obtained raffinate is the battery-grade manganese sulfate solution.

2. The method according to claim 1, characterized in that The saponified di(2-ethylhexyl) phosphate is prepared from di(2-ethylhexyl) phosphate and sulfonated kerosene, and the volume fraction of di(2-ethylhexyl) phosphate in the saponified di(2-ethylhexyl) phosphate is 20-25%.

3. The method according to claim 1, characterized in that In step S1, the multi-stage countercurrent extraction is a 5-stage countercurrent extraction, and the volume ratio of the first extractant to the manganese-containing solution in each stage is 1-3:

1.

4. The method according to claim 1, wherein In step S2, the multi-stage countercurrent pickling refers to a three-stage countercurrent pickling, and the volume ratio of the organic phase I loaded with manganese to sulfuric acid in each stage is 5:

1.

5. The method according to claim 1, wherein In step S3, the concentration of sulfuric acid is 2-2.5 mol / L; The first stage of stripping adopts 5-stage countercurrent stripping, and the volume ratio of the acid-washed organic phase I to sulfuric acid in each stage is 16-17:1; In the second stage stripping, the volume ratio of the organic phase to sulfuric acid in the first stage of each stage is 16-17:

1.

6. The method according to claim 1, characterized in that In step S4, the multi-stage countercurrent extraction is a 5-stage countercurrent extraction, and the volume ratio of the second extractant in each stage to the first stage manganese sulfate solution is 20-21:

1.

7. The method according to claim 1, characterized in that The saponified di(2,4,4-trimethylpentyl)phosphinic acid is prepared from di(2,4,4-trimethylpentyl)phosphinic acid and sulfonated kerosene. In the saponified di(2,4,4-trimethylpentyl)phosphinic acid, the volume fraction of di(2,4,4-trimethylpentyl)phosphinic acid is 15-20%; and the saponification rate of the saponified di(2,4,4-trimethylpentyl)phosphinic acid is 40%-45%.

8. The method according to claim 1, characterized in that In step S5, the concentration of the sulfuric acid is 0.1-0.3 mol / L; the multi-stage countercurrent pickling is a three-stage countercurrent pickling, and the volume ratio of the manganese-loaded organic phase II to the sulfuric acid in each stage is 5:

1.

9. The method according to claim 1, characterized in that In step S6, the concentration of the sulfuric acid is 2-2.5 mol / L, the multi-stage countercurrent stripping is 6-stage countercurrent stripping, and the volume ratio of the acid-washed organic phase II to the sulfuric acid in each stage is 16-17:

1.

10. The method according to claim 1, characterized in that In step S7, in the countercurrent extraction, the volume ratio of the copper extractant to the manganese sulfate solution in each stage is 2-3:1.

Images