Method for preparing battery grade manganese sulfate from manganese-containing solution

Abstract

The invention discloses a method for preparing battery-grade manganese sulfate from a manganese-containing solution. The method comprises the following steps: performing multi-stage counter-current extraction on a manganese-containing solution through a first extraction agent to obtain a manganese-loaded organic phase I, and then performing counter-current acid pickling to obtain an acid-pickled organic phase I; sulfuric acid is added for two-stage reverse extraction, a first-stage manganese sulfate solution and a first-stage organic phase are obtained through first-stage reverse extraction, acid is added into the first-stage organic phase for second-stage reverse extraction, and a second-stage manganese sulfate solution and a regenerated organic phase are obtained; adding a second extraction agent into the first-stage manganese sulfate solution, carrying out counter-current extraction to obtain a manganese-loaded organic phase II, and carrying out multi-stage counter-current acid pickling to obtain an acid-pickled organic phase II; carrying out multi-stage countercurrent reverse extraction to obtain a manganese sulfate solution; and finally, adding a copper extraction agent to obtain the battery-grade manganese sulfate. According to the method, the battery-grade manganese sulfate is prepared through a multi-section extraction technology, no chemical reagent is needed for special impurity removal, no solid waste is discharged, and the industrial production cost can be reduced.

Description

Technical Field

[0001] The invention belongs to the technical field of manganese sulfate preparation, and in particular relates to a method for preparing battery-grade manganese sulfate from a manganese-containing solution. Background Art

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

[0003] At present, sulfuric acid solution is made from retired ternary lithium batteries as raw materials, and crude manganese sulfate is obtained through extraction, and then heavy metals are removed by barium sulfide, iron is removed by lime pH adjustment, and calcium and magnesium are removed by sodium fluoride, and then battery-grade manganese sulfate is obtained through extraction. For the manganese sulfate solution after acid leaching of manganese oxide ore with more impurities, the main process is to oxidize ferrous ions with high-grade manganese oxide ore and add ferric sulfate to precipitate potassium and sodium, neutralize iron with carbonation, remove calcium and magnesium with fluoride, remove heavy metals with sulfide, and concentrate and crystallize to produce battery-grade high-purity manganese sulfate. Although the above method can also produce battery-grade manganese sulfate, the process flow is complicated, more chemical auxiliary materials are required, the industrial cost is high, and the three wastes generated in the process are relatively serious. Summary of the invention

[0004] In view of the shortcomings of the prior art, the present invention provides a method for preparing battery-grade manganese sulfate from a manganese-containing solution. The present invention prepares battery-grade manganese sulfate through a three-stage extraction technology, does not require the use of chemical reagents for special impurity removal, achieves no solid waste discharge, and can reduce industrial production costs.

[0005] The technical solution of the present invention is as follows:

[0006] The present invention firstly protects a method for preparing battery-grade manganese sulfate from a manganese-containing solution, the method comprising the following steps:

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

[0008] 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;

[0009] S3, then the acid-washed organic phase I is stripped in two stages with sulfuric acid, the first stripping adopts multi-stage countercurrent stripping to obtain the first manganese sulfate solution and the first organic phase, and then sulfuric acid is added to the first organic phase for the second stripping to obtain the second manganese sulfate solution and the regenerated organic phase;

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

[0011] S5: using sulfuric acid to perform multi-stage countercurrent acid washing on the manganese-loaded organic phase II obtained in step S4 to obtain an acid-washed organic phase II;

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

[0013] S7: Finally, the manganese sulfate solution in step S6 is subjected to countercurrent extraction with a copper extractant, and the obtained raffinate is 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%; 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 a 5-stage countercurrent extraction, in each stage, the volume ratio of the first extractant to the manganese-containing solution is 1-3:1, the mixture is mixed for 3-5 minutes, and the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining an organic phase I loaded with manganese.

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

[0019] Preferably, in step S3, the concentration of sulfuric acid is 2-2.5 mol / L; the first stage stripping is specifically: 5-stage countercurrent stripping is adopted, and the volume ratio of the pickling organic phase I to sulfuric acid is 16-17:1 in each stage, and the mixture is mixed for 3-5 minutes, and then the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining 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: 3-stage countercurrent stripping is adopted, and the volume ratio of the first stage organic phase to sulfuric acid is 16-17:1 in each stage, and the mixture is mixed for 3-5 minutes, and then the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining a second stage manganese sulfate solution and a regenerated organic phase.

[0020] Preferably, in step S4, the multi-stage countercurrent extraction is a 5-stage countercurrent extraction, and in each stage, the second extractant and the first stage manganese sulfate solution are mixed at a volume ratio of 20-21:1 for 3-5 minutes, and then allowed to stand for 10-15 minutes to separate layers, to obtain an organic phase II loaded with manganese.

[0021] Preferably, the saponified di(2,4,4-trimethylpentyl)phosphinic acid is prepared from di(2,4,4-trimethylpentyl)phosphinic acid and 260# sulfonated kerosene, and 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%.

[0022] Preferably, in step S5, the concentration of the sulfuric acid is 0.1-0.3 mol / L; the multi-stage countercurrent pickling is a 3-stage countercurrent pickling, and each stage is mixed with the manganese-loaded organic phase II and sulfuric acid at a volume ratio of 5:1 for 3-5 minutes, and then allowed to stand for 10-15 minutes to separate layers to obtain the pickled organic phase II.

[0023] Preferably, 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 each stage is mixed for 3-5 minutes at a volume ratio of the acid-washed organic phase II to sulfuric acid of 16-17:1, and then allowed to stand for 10-15 minutes to separate the layers, to obtain a manganese sulfate solution.

[0024] Preferably, in step S7, the countercurrent extraction is a two-stage countercurrent extraction, and the volume ratio of the copper catalyst to the manganese sulfate solution in each stage is 2-3:1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes for stratification, and the obtained raffinate is a battery-grade manganese sulfate solution.

[0025] The beneficial technical effects of the present invention are:

[0026] According to the present invention, after manganese is extracted by a saponified di(2-ethylhexyl) phosphate extractant, acid is used to wash away impurities that are difficult to extract, and then manganese in the organic material is stripped in two stages to remove impurities that are easy to extract, thereby achieving efficient separation of manganese and impurities, and then the first stage manganese sulfate is purified and copper is removed by a di(2,4,4-trimethylpentyl)phosphinate extractant and a copper extractant, so as to obtain battery-grade manganese sulfate.

[0027] The invention uses three-stage extraction, does not need to use chemical reagents for impurity removal, and reduces production costs. BRIEF DESCRIPTION OF THE DRAWINGS

[0028] Figure 1 The figure is the relationship between the extraction order of metals by di(2-ethylhexyl) phosphate and the pH value of the aqueous phase.

[0029] Figure 2 It is a process flow chart of the present invention. DETAILED DESCRIPTION

[0030] The present invention is described in detail below in conjunction with the accompanying drawings and embodiments.

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

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

[0033] 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;

[0034] S3, then the acid-washed organic phase I is stripped in two stages with sulfuric acid, the first stripping adopts multi-stage countercurrent stripping to obtain a first stage manganese sulfate solution and a first stage organic phase, and then the first stage organic phase is stripped in a second stage with sulfuric acid to obtain a second stage manganese sulfate solution and a regenerated organic phase;

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

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

[0037] S6: The acid-washed organic phase II is again subjected to multi-stage countercurrent stripping with sulfuric acid to obtain a manganese sulfate solution;

[0038] S7: finally, countercurrent extraction is performed on the manganese sulfate solution in step S6 using a copper extractant, and the obtained raffinate 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 invention, 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%; the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%-45%.

[0041] In some embodiments of the present invention, the di(2,4,4-trimethylpentyl)phosphinic acid is prepared from di(2,4,4-trimethylpentyl)phosphinic acid and 260# sulfonated kerosene, and 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 invention, the sulfonated kerosene is 260# sulfonated kerosene.

[0043] In some embodiments of the present invention, 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 invention contains hydroxyl groups, and the extraction effect is improved by limiting the saponification rate. The second extractant of the present invention contains hydroxyl groups, and a higher extraction rate of manganese can be achieved during the extraction.

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

[0046] In some embodiments of the present invention, in step S1, the manganese-containing solution is used to leach the positive and negative mixed black powder obtained from retired ternary lithium batteries using reducing agents such as sulfuric acid and hydrogen peroxide. The leachate is initially copper-free by iron powder, and then iron and aluminum are initially removed by soda ash 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 is understandable that, in the present invention, the pH of the original feed solution cannot be less than 3. When it is less than 3, the extraction efficiency will be significantly reduced.

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

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

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

[0051] It can be understood that in step S2, the impurity ions of cobalt and nickel in the organic phase I loaded with manganese are removed by acid countercurrent pickling to obtain the pickled organic phase I containing manganese and zinc, calcium and iron ions.

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

[0053] In some embodiments of the present invention, in step S3, the first stage of stripping is specifically: 5-stage countercurrent stripping is adopted, and each stage is mixed for 3-5 minutes according to the volume ratio of the acid-washed organic phase I and sulfuric acid of 16-17:1, and then allowed to stand for 10-15 minutes to separate the layers, so as to obtain a first stage of manganese sulfate solution and a first stage of organic phase; wherein the content of manganese ions in the first stage of 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 is understandable that in the first stage of stripping of the present invention, the manganese content in the di(2-ethylhexyl)phosphate extractant cannot exceed 90% of the total manganese in the organic matter. When it exceeds 90%, the impurities in the manganese sulfate solution of the first stage will exceed the standard.

[0055] In some embodiments of the present invention, in step S3, the second stage stripping is specifically: three-stage countercurrent stripping is adopted, and each stage is mixed for 3-5 minutes according to the volume ratio of the first stage organic phase to sulfuric acid of 16-17:1, and then left to stand for 10-15 minutes to separate and obtain the second stage manganese sulfate solution and the regenerated organic phase. In this step, the manganese sulfate solution obtained in the second stage has a low manganese content and high impurities such as calcium and zinc.

[0056] It can be understood that in step S3, a 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 are obtained through the first stripping, and the organic phase is stripped for the second time to obtain a second manganese sulfate solution containing the above-mentioned impurity ions and an organic phase that can be recycled, thereby realizing the recycling and reuse of the organic phase.

[0057] In some embodiments of the present invention, in step S4, the multi-stage countercurrent extraction is a 5-stage countercurrent extraction, and the volume ratio of the second extractant to the first stage manganese sulfate solution in each stage is 20-21:1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate the layers, thereby obtaining an organic phase II loaded with manganese.

[0058] It can be understood that in step S4, the impure metal ions in the first stage manganese sulfate solution are extracted again by adding the second extractant to obtain an organic phase containing copper ions, manganese ions, etc.

[0059] In some embodiments of the present invention, in step S5, the concentration of the sulfuric acid is 0.1-0.3 mol / L; the multi-stage countercurrent pickling is a 3-stage countercurrent pickling, and the volume ratio of the organic phase II loaded with manganese to sulfuric acid in each stage is 5:1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate the layers, thereby obtaining the pickled organic phase II.

[0060] It can be understood that step S5 removes acid-soluble impurity ions, namely, sodium, cobalt, calcium, nickel and other impurity ions, by acid washing to obtain an organic phase containing copper ions and manganese ions.

[0061] In some embodiments of the present invention, 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, the volume ratio of the acid-washing organic phase II to sulfuric acid in each stage is 16-17:1, after mixing for 3-5 minutes, standing for 10-15 minutes to separate the layers, to obtain a manganese sulfate solution.

[0062] It can be understood that in step S6, a manganese sulfate solution containing manganese ions and copper ions is obtained by stripping.

[0063] In some embodiments of the present invention, in step S7, the countercurrent extraction is a two-stage countercurrent extraction, and the volume ratio of the copper catalyst to the manganese sulfate solution in each stage is 2-3:1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate the layers, and the raffinate obtained is a battery-grade manganese sulfate solution.

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

[0065] It is understood that in the present invention, the mixing time of the organic phase and the aqueous phase cannot be less than 3 minutes, and the standing time cannot be less than 10 minutes. If the mixing time is too short, the extraction reaction will be incomplete, and if it is too long, the extraction reaction will not be affected, but the efficiency will be delayed.

[0066] The present invention will be further described below by way of examples and the like.

[0067] Embodiment 1:

[0068] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 1:1 for 5 minutes, and then standing for 10 minutes to separate the layers to obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion of di(2-ethylhexyl) phosphate is 20%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%;

[0069] (2) The impurities in the loaded organic phase of step (1) are subjected to three-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed for 3 minutes at a volume ratio of 5:1 for organic and sulfuric acid, and then allowed to stand for 10 minutes to obtain an organic phase, and then the organic phase is stripped in two stages with 2 mol / L sulfuric acid. The first stage adopts five-stage countercurrent stripping, mixed for 3 minutes at a volume ratio of 16:1 for organic and sulfuric acid, and then allowed to stand for 10 minutes to obtain a first stage manganese sulfate solution and an organic phase. The manganese content in the manganese sulfate solution obtained in the first stage accounts for 70% of the manganese in the loaded organic phase and the content of impurities such as calcium and zinc is low, and the pH is 3.5-4. The second stage adopts three-stage countercurrent stripping, mixed for 3 minutes at a volume ratio of 16:1 for organic and sulfuric acid, and then allowed to stand for 10 minutes to obtain a second stage manganese sulfate solution and a regenerated organic phase. The manganese content of the manganese sulfate solution obtained in the second stage is low and the content of impurities such as calcium and zinc is high;

[0070] (3) the manganese sulfate solution in the first stage is subjected to 5-stage countercurrent extraction of manganese with a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, and the extractant and the manganese-containing solution are mixed at a volume ratio of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion of di(2,4,4-trimethylpentyl)phosphinic acid is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl)phosphinic acid extractant is 40%;

[0071] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.1 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 3 minutes, then standing for 10 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 16:1 for 3 minutes, then standing for 10 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0073] Embodiment 2:

[0074] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 3:1 for 5 minutes, and then standing for 15 minutes to separate the layers to obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion 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 of step (1) are subjected to three-stage countercurrent acid washing with 0.3 mol / L sulfuric acid, mixed for 5 minutes at a volume ratio of 5:1 between organic and sulfuric acid, and then allowed to stand for 15 minutes to separate into layers to obtain an organic phase, and then the organic phase is stripped in two stages with 2.5 mol / L sulfuric acid. The first stage adopts five-stage countercurrent stripping, mixed for 5 minutes at a volume ratio of 17:1 between organic and sulfuric acid, and then allowed to stand for 15 minutes to separate into layers to obtain a first stage manganese sulfate solution and an organic phase. The manganese content in the manganese sulfate solution obtained in the first stage accounts for 90% of the manganese in the loaded organic phase and the content of impurities such as calcium and zinc is low, and the pH value is 3.5-4. The second stage adopts three-stage countercurrent stripping, mixed for 5 minutes at a volume ratio of 17:1 between organic and sulfuric acid, and then allowed to stand for 15 minutes to separate into layers to obtain a second stage manganese sulfate solution and a regenerated organic phase. The manganese content in the manganese sulfate solution obtained in the second stage is low and the content of impurities such as calcium and zinc is high;

[0076] (3) the manganese sulfate solution in the first stage is subjected to 5-stage countercurrent extraction of manganese with a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, and the extractant and the manganese-containing solution are mixed at a volume ratio of 21:1 for 5 minutes, and then allowed to stand for 15 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion 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%;

[0077] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.3 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 5 minutes, then standing for 15 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 17:1 for 5 minutes, then standing for 15 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0079] Embodiment 3:

[0080] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 2:1 for 4 minutes, and then standing for 13 minutes to separate and obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion of di(2-ethylhexyl) phosphate is 25%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 40%;

[0081] (2) The impurities in the loaded organic phase of step (1) are subjected to three-stage countercurrent acid washing with 0.2 mol / L sulfuric acid, mixed for 4 minutes at a volume ratio of 5:1 between organic and sulfuric acid, and then allowed to stand for 13 minutes to separate into layers to obtain an organic phase, and then the organic phase is stripped in two stages with 2.5 mol / L sulfuric acid. The first stage adopts five-stage countercurrent stripping, mixed for 4 minutes at a volume ratio of 17:1 between organic and sulfuric acid, and then allowed to stand for 13 minutes to separate into layers to obtain a first stage manganese sulfate solution and an organic phase. The manganese content in the manganese sulfate solution obtained in the first stage accounts for 80% of the manganese in the loaded organic phase and the content of impurities such as calcium and zinc is low, and the pH is 3.5-4. The second stage adopts three-stage countercurrent stripping, mixed for 4 minutes at a volume ratio of 17:1 between organic and sulfuric acid, and then allowed to stand for 13 minutes to separate into layers to obtain a second stage manganese sulfate solution and a regenerated organic phase. The manganese content in the manganese sulfate solution obtained in the second stage is low and the content of impurities such as calcium and zinc is high;

[0082] (3) the manganese sulfate solution in the first stage is subjected to 5-stage countercurrent extraction of manganese with a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, and the extractant and the manganese-containing solution are mixed at a volume ratio of 21:1 for 4 minutes, and then allowed to stand for 13 minutes to separate and obtain a manganese-loaded organic phase, wherein 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 proportion 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%;

[0083] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.2 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 5:1 for 4 minutes, then standing for 13 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 17:1 for 4 minutes, then standing for 13 minutes to separate the organic phase to obtain a manganese sulfate solution;

[0084] (5) The manganese sulfate solution obtained in step (4) was subjected to a second-stage countercurrent extraction of copper using a copper extractant. The extractant and the manganese sulfate solution were mixed at a volume ratio of 3:1 for 4 minutes, and then allowed to stand for 13 minutes to separate the layers. The raffinate obtained was battery-grade manganese sulfate, wherein the content (g / L) of each element is shown in Table 1.

[0085] Comparative Example 1:

[0086] (1) the manganese-containing solution is subjected to five-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 allowed to stand for 15 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion 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) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (1) with 0.1 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 5 minutes, then standing for 15 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 17:1 for 5 minutes, then standing for 15 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0089] Comparative Example 2:

[0090] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 1:1 for 5 minutes, and then standing for 10 minutes to separate the layers to obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion 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 of step (1) are subjected to three-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed at a volume ratio of 5:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain an organic phase, and then the organic phase is stripped with 2 mol / L sulfuric acid, mixed at a volume ratio of 15:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese sulfate solution and an organic phase, wherein 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) the manganese sulfate solution in step (2) is subjected to five-stage countercurrent extraction of manganese using a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, the extractant and the manganese-containing solution are mixed at a volume ratio of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion of di(2,4,4-trimethylpentyl)phosphinic acid is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl)phosphinic acid extractant is 40%;

[0093] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.1 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 3 minutes, then standing for 10 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 16:1 for 3 minutes, then standing for 10 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0095] Comparative Example 3:

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

[0097] (2) performing a three-stage countercurrent acid wash on the impurities in the loaded organic phase of step (1) with 0.1 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 5:1 for 3 minutes, then standing for 10 minutes to separate the organic phase, and then performing a one-stage stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 15:1 for 3 minutes, then standing for 10 minutes to separate the organic phase and obtain a manganese sulfate solution and an organic phase, wherein the manganese content in the manganese sulfate solution accounts for 100% of the manganese in the loaded organic phase, and the pH value is 1.5-2;

[0098] (3) adding barium sulfide to the manganese sulfate solution in step (2) at a molar amount twice that of the total molar amount of copper and zinc, reacting for 1 hour and then filtering to obtain a filtrate;

[0099] (4) subjecting the filtrate in step (3) to 5-stage countercurrent extraction of manganese using a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, mixing the extractant and the manganese-containing solution at a volume ratio of 20:1 for 3 minutes, and then standing for 10 minutes to separate the layers to obtain a manganese-loaded organic phase, wherein 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 proportion of di(2,4,4-trimethylpentyl)phosphinic acid is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl)phosphinic acid extractant is 40%;

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

[0101] Comparative Example 4:

[0102] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 1:1 for 5 minutes, and then standing for 10 minutes to separate the layers to obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion of di(2-ethylhexyl) phosphate is 20%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 35%;

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

[0104] (3) the manganese sulfate solution in the first stage is subjected to 5-stage countercurrent extraction of manganese with a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, and the extractant and the manganese-containing solution are mixed at a volume ratio of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion of di(2,4,4-trimethylpentyl)phosphinic acid is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl)phosphinic acid extractant is 40%;

[0105] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.4 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 3 minutes, then standing for 10 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 16:1 for 3 minutes, then standing for 10 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0107] Comparative Example 5:

[0108] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 1:1 for 5 minutes, and then standing for 10 minutes to separate the layers to obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion of di(2-ethylhexyl) phosphate is 20%, and the saponification rate of the di(2-ethylhexyl) phosphate extractant is 55%;

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

[0110] (3) the manganese sulfate solution in the first stage is subjected to 5-stage countercurrent extraction of manganese with a saponified di(2,4,4-trimethylpentyl)phosphinic acid extractant, and the extractant and the manganese-containing solution are mixed at a volume ratio of 20:1 for 3 minutes, and then allowed to stand for 10 minutes to separate into layers to obtain a manganese-loaded organic phase, wherein 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 proportion of di(2,4,4-trimethylpentyl)phosphinic acid is 15%, and the saponification rate of the di(2,4,4-trimethylpentyl)phosphinic acid extractant is 55%;

[0111] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.1 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 5:1 for 3 minutes, then standing for 10 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase and sulfuric acid at a volume ratio of 16:1 for 3 minutes, then standing for 10 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0113] Comparative Example 6:

[0114] (1) using a saponified di(2-ethylhexyl) phosphate extractant to perform 5-stage countercurrent extraction on manganese in a manganese-containing solution, mixing the extractant and the manganese-containing solution at a volume ratio of 1:1 for 2 minutes, and then standing for 8 minutes to separate and obtain an organic phase loaded with manganese, wherein the pH of the manganese-containing solution is 4-5, and the di(2-ethylhexyl) phosphate extractant is prepared from di(2-ethylhexyl) phosphate and 260# sulfonated kerosene, wherein the volume proportion of di(2-ethylhexyl) phosphate is 20%, 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 three-stage countercurrent acid washing with 0.1 mol / L sulfuric acid, mixed for 2 minutes at a volume ratio of 5:1 for organic and sulfuric acid, and then allowed to stand for 8 minutes to obtain an organic phase, and then the organic phase is stripped in two stages with 2 mol / L sulfuric acid. The first stage adopts five-stage countercurrent stripping, mixed for 2 minutes at a volume ratio of 16:1 for organic and sulfuric acid, and then allowed to stand for 8 minutes to obtain a first stage manganese sulfate solution and an organic phase. The manganese content in the manganese sulfate solution obtained in the first stage accounts for 70% of the manganese in the loaded organic phase, and the pH is 3.5-4. The second stage adopts three-stage countercurrent stripping, mixed for 2 minutes at a volume ratio of 16:1 for organic and sulfuric acid, and then allowed to stand for 8 minutes to obtain a second stage manganese sulfate solution and a regenerated organic phase. The manganese content of the manganese sulfate solution obtained in the second stage is low and impurities such as calcium and zinc are high;

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

[0117] (4) performing a three-stage countercurrent acid wash on the impurities in the organic phase loaded in step (3) with 0.1 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 5:1 for 2 minutes, then standing for 8 minutes to separate the organic phase, and then performing a six-stage countercurrent stripping on the organic phase with 2 mol / L sulfuric acid, mixing the organic phase with sulfuric acid at a volume ratio of 16:1 for 2 minutes, then standing for 8 minutes to separate the organic phase to obtain a manganese sulfate solution;

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

[0119] Table 1: Element contents in sulfuric acid solution in Examples and Comparative Examples

[0120]

[0121] As can be seen from Table 1, Comparative Example 1 did not use saponified di(2-ethylhexyl)phosphate extractant and corresponding steps (1) and (2), and the content of zinc ions and calcium ions was significantly increased. Comparative Example 2 only performed one extraction, and the obtained battery-grade manganese sulfate solution had a high calcium ion content. Comparative Example 3 only performed one stripping, and did not use a copper extractant, and the obtained battery-grade manganese sulfate solution had a high copper ion and calcium ion content. Comparative Example 4 changed the concentration of sulfuric acid in steps (2) and (4), and the obtained calcium ion concentration was significantly increased. Comparative Example 5 changed the saponification rate of the extractant, and the zinc ion content was higher. Comparative Example 6 changed the mixing and standing time, and the manganese ion content in the obtained solution was low, and the content of copper ions, zinc ions, etc. was significantly increased. The embodiments of the present application limit the extraction process and the parameters of each stage, so that the manganese ion content in the obtained sulfuric acid solution is higher and the content of other ions is lower.

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

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 an organic phase I loaded with manganese; 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, then the acid-washed organic phase I is stripped in two stages with sulfuric acid, the first stripping adopts multi-stage countercurrent stripping to obtain a first stage manganese sulfate solution and a first stage organic phase, and then the first stage organic phase is stripped in a second stage with sulfuric acid to obtain a second stage manganese sulfate solution and a regenerated organic phase; S4: Then, the first section of manganese sulfate solution obtained in step S3 is subjected to multi-stage countercurrent extraction using a second extractant to obtain an organic phase II loaded with manganese. S5: using sulfuric acid to perform multi-stage countercurrent acid washing on the manganese-loaded organic phase II obtained in step S4 to obtain an acid-washed organic phase II; S6: The acid-washed organic phase II is subjected to multi-stage countercurrent stripping with sulfuric acid again to obtain a manganese sulfate solution; S7: finally, countercurrent extraction is performed on the manganese sulfate solution in step S6 using a copper extractant, and the obtained raffinate 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.

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, 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%.

3. The method according to claim 1, characterized in that In step S1, the pH value of the manganese-containing solution is 4-5; The multi-stage countercurrent extraction is a 5-stage countercurrent extraction, in which the volume ratio of the first extractant to the manganese-containing solution is 1-3:1 in each stage, the mixture is mixed for 3-5 minutes, and the mixture is allowed to stand for 10-15 minutes to separate into layers, thereby obtaining an organic phase I loaded with manganese.

4. The method according to claim 1, characterized in that In step S2, the concentration of sulfuric acid is 0.1-0.3 mol / L; the multi-stage countercurrent pickling refers to 3-stage countercurrent pickling, and the volume ratio of the organic phase I loaded with manganese to sulfuric acid in each stage is 5:1, mixed for 3-5 minutes, and allowed to stand for 10-15 minutes to separate layers to obtain the pickled organic phase I.

5. The method according to claim 1, characterized in that In step S3, the concentration of sulfuric acid is 2-2.5 mol / L; The first stage of stripping is specifically: using 5-stage countercurrent stripping, in each stage, the volume ratio of the acid-washed organic phase I to sulfuric acid is 16-17:1, mixing for 3-5 minutes, standing for 10-15 minutes, and stratifying to obtain the first stage of manganese sulfate solution and the first stage of 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, and the volume ratio of the organic phase in the first stage to sulfuric acid in each stage is 16-17:

1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes and separated into layers to obtain the second stage manganese sulfate solution and the regenerated organic phase.

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 to the first stage manganese sulfate solution in each stage is 20-21:

1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate the layers, thereby obtaining an organic phase II loaded with manganese.

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 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 3-stage countercurrent pickling, and the volume ratio of the organic phase II loaded with manganese to sulfuric acid in each stage is 5:

1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes to separate layers, thereby obtaining the pickled organic phase II.

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, the volume ratio of the acid-washed organic phase II to sulfuric acid in each stage is 16-17:1, after mixing for 3-5 minutes, standing for 10-15 minutes to separate the layers, to obtain a manganese sulfate solution.

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

1. After mixing for 3-5 minutes, the mixture is allowed to stand for 10-15 minutes for stratification, and the obtained raffinate is a battery-grade manganese sulfate solution.

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