Method for recovering manganese from MHP high-acid leaching residues

Abstract

The invention provides a method for recovering manganese from MHP high-acid leaching residues. The method comprises the following steps: washing the MHP high-acid leaching residues with dilute sulphuric acid to obtain washing residues; concentrated sulfuric acid and a reducing agent are added into the washing residues for heating reduction acid leaching; after reduction acid leaching is completed, solid-liquid separation is conducted to obtain a leaching solution, and the content of impurity metal in the leaching solution is detected; according to the content of impurity metal in the leachate, an impurity removing agent is added into the leachate for impurity removal, and impurity-removed liquid is obtained; evaporating and crystallizing the impurity-removed liquid to obtain crude manganese sulfate crystals; and dissolving the crude manganese sulfate crystal, and carrying out secondary crystallization to obtain the high-purity manganese sulfate crystal. The method for recovering manganese from MHP high-acid leaching residues can save energy and reduce consumption, and is low in production cost and environmentally friendly.

Description

Technical Field

[0001] The invention relates to the technical field of solid waste resource utilization, and in particular to a method for recovering manganese from MHP high-acid leaching residue. Background Art

[0002] Manganese is a non-ferrous metal element of great strategic significance, used in the production of steel, ferromanganese, non-ferrous alloys, dry batteries, coatings and other chemicals. With the rapid development of my country's industry, the demand for manganese and manganese compounds is growing. However, manganese resources are gradually being depleted. With the depletion of manganese ore, manganese metal recovery and efficient utilization of poor manganese ore have attracted more and more attention. Due to the rise and development of the battery industry, the requirements for the quality and performance of manganese sulfate products are becoming increasingly stringent. Due to the sharp increase in the demand for manganese sulfate, the leaching of manganese sources has become increasingly important in global metallurgical programs. In order to protect the environment and ensure the health of humans and animals, the recycling of manganese is becoming increasingly important.

[0003] At present, in the process of producing nickel sulfate, cobalt sulfate and manganese sulfate crystals using MHP (nickel cobalt manganese hydroxide mixture), the leaching stage often adopts a high acid leaching process, that is, when MHP, sulfuric acid and water are mixed for leaching, the sulfuric acid acidity at the reaction end point is controlled to be greater than 10g / L. In this production process, high acid leaching slag is produced, and the manganese content in this high acid leaching slag is as high as 40% or more, and the total amount of metal impurities does not exceed 5%. It is one of the high-quality raw materials for preparing manganese materials.

[0004] With the development of the new energy industry and the rapid development of ternary batteries, the domestic consumption of MHP has increased sharply, with more than 1 million tons of MHP imported each year, and the high-acid leaching process produces about 30,000 tons of high-acid leaching slag each year. Therefore, it is of great significance to use high-acid leaching slag to recover manganese metal.

[0005] At present, there are two methods for recovering manganese metal from high-acid leaching slag: the traditional method of preparing manganese sulfate crystals by electrolyzing manganese, and the method of preparing manganese sulfate by full extraction process using extraction method in hydrometallurgical industry. Among them, the more commonly used method is the pyrometallurgical-hydrometallurgical combined process. That is, the high-acid leaching slag is first dried and reduced and calcined, and then battery-grade manganese sulfate crystals are prepared through leaching, impurity removal, crystallization and other processes. However, this process method has high energy consumption during the pyrometallurgical treatment process, and the dust output during the process is large, which makes the production environment conditions poor.

[0006] Therefore, there is an urgent need for a method for recovering manganese from MHP high-acid leaching slag that can save energy and reduce consumption, has low production cost and is environmentally friendly. Summary of the invention

[0007] The technical problem to be solved by the present invention is to provide a method for recovering manganese from MHP high-acid leaching slag which can save energy and reduce consumption, has low production cost and is environmentally friendly.

[0008] In order to solve the above technical problems, the present invention provides a method for recovering manganese from MHP high acid leaching residue, comprising the following steps:

[0009] Washing the MHP high acid leaching residue with dilute sulfuric acid to obtain washing residue;

[0010] Add concentrated sulfuric acid and a reducing agent to the washing residue for heating reduction acid leaching;

[0011] After the reduction acid leaching is completed, the solid-liquid separation is performed to obtain the leachate, and the impurity metal content in the leachate is detected;

[0012] According to the content of impurity metals in the leaching solution, an impurity remover is added to the leaching solution to remove impurities and obtain a de-impurity liquid;

[0013] After impurities are removed, the liquid is evaporated and crystallized to obtain crude manganese sulfate crystals;

[0014] The crude manganese sulfate crystals are dissolved and secondary crystallized to obtain high-purity manganese sulfate crystals.

[0015] Furthermore, the mixture of the dilute sulfuric acid and the MHP high-acid leaching residue is heated at a constant temperature in a water bath at a temperature of 60-90° C., and the mixture of the dilute sulfuric acid and the MHP high-acid leaching residue is continuously stirred with a stirrer.

[0016] Furthermore, the washing time of the MHP high-acid leaching residue with the dilute sulfuric acid is 40 min-80 min, and the concentration of the dilute sulfuric acid is not less than 20 g / L.

[0017] Furthermore, concentrated sulfuric acid and a reducing agent are added to the washing residue for heating and reduction acid leaching in a water bath, the heating temperature is 60-90° C., and the reduction acid leaching time is 2h-5h.

[0018] Furthermore, the reducing agent is one or more of hydrogen peroxide, sodium pyrosulfite and sulfur dioxide, and the pH of the mixed solution of the washing residue, concentrated sulfuric acid and reducing agent is finally controlled at 2.0-3.0.

[0019] Furthermore, the mixed solution of the washing residue, concentrated sulfuric acid and reducing agent is subjected to reduction acid leaching under stirring of a stirrer.

[0020] Furthermore, the detection of the impurity metal content is the detection of copper, zinc, iron, nickel and cobalt in the leachate.

[0021] Furthermore, the impurity remover is one or more of manganese powder, sodium hydrosulfide and sodium carbonate.

[0022] Furthermore, the evaporative crystallization and secondary crystallization are high-temperature thermal crystallization, and the crystallization temperature is controlled at 80-150°C.

[0023] The present invention provides a method for recovering manganese from MHP high-acid leaching residue, which comprises washing the high-acid leaching residue to reduce soluble impurities therein, then sequentially performing reduction leaching and chemical impurity removal to obtain a de-impurity liquid, and finally performing evaporation crystallization and recrystallization on the de-impurity liquid to obtain battery-grade manganese sulfate crystals.

[0024] The method for recovering manganese from MHP high-acid leaching residue provided by the present invention does not require electrolysis and can achieve energy saving and consumption reduction compared to the traditional method for preparing manganese sulfate crystals by electrolyzing manganese.

[0025] In addition, the method for recovering manganese from MHP high-acid leaching slag provided by the present invention can save acid and alkali consumption and significantly reduce the production cost compared with the method of refining manganese sulfate by full extraction process using extraction method in the hydrometallurgical industry.

[0026] At the same time, the method for recovering manganese from MHP high-acid leaching residue provided by the present invention adopts a fully wet treatment method, compared with the process method for preparing manganese sulfate by combining pyrometallurgy and hydrometallurgy, so that no dust is generated at the production site, the working environment conditions are good, it is environmentally friendly, the impact on the health of the workers is small, and the energy consumption is low, the production cost is low, and the economic benefits are good. BRIEF DESCRIPTION OF THE DRAWINGS

[0027] Figure 1 A flow chart of a method for recovering manganese from MHP high acid leaching slag provided in an embodiment of the present invention. DETAILED DESCRIPTION

[0028] See also Figure 1 The present invention provides a method for recovering manganese from MHP high acid leaching residue, comprising the following steps:

[0029] Step 1) washing the MHP high-acid leaching residue with dilute sulfuric acid to dissolve the soluble substances adhering to the MHP high-acid leaching residue.

[0030] In order to effectively dissolve and remove the soluble substances adhering to the MHP high-acid leaching residue, the mixture of dilute sulfuric acid and MHP high-acid leaching residue is placed in a water bath at a temperature of 60-90° C. and heated at a constant temperature, and the mixture of dilute sulfuric acid and MHP high-acid leaching residue is continuously stirred with a stirrer.

[0031] Furthermore, in order to more effectively remove the soluble substances adhering to the MHP high-acid leaching residue, the higher the concentration of dilute sulfuric acid, the better the dissolution and impurity removal effect. However, considering the actual production cost, the concentration of the dilute sulfuric acid used is not less than 20 g / L, but not more than 1000 g / L.

[0032] At the same time, in order to fully dissolve and remove the soluble substances adhering to the MHP high-acid leaching residue, the washing time of the MHP high-acid leaching residue with dilute sulfuric acid is controlled to be 40min-80min.

[0033] The MHP high-acid leaching residue is fully washed with dilute sulfuric acid and then solid-liquid separation is performed to obtain a solid washing residue, wherein the main component of the washing residue is manganese dioxide, and also includes some silicate compounds. The liquid obtained by solid-liquid separation is returned to the MHP high-acid leaching residue recovery system to further recover the effective components in the liquid.

[0034] Step 2) adding concentrated sulfuric acid and a reducing agent to the washing residue for heating reduction acid leaching.

[0035] When concentrated sulfuric acid and a reducing agent are added to the washing residue for heating reduction acid leaching, the concentrated sulfuric acid is also used to adjust the acidity of the mixed solution, and the pH of the final mixed solution is controlled at 2.0-3.0.

[0036] Wherein, the reducing agent is one or more of hydrogen peroxide, sodium pyrosulfite and sulfur dioxide.

[0037] In order to improve the reduction acid leaching efficiency of washing residue, the washing residue is heated in a water bath when it is subjected to reduction acid leaching in concentrated sulfuric acid and a reducing agent, wherein the heating temperature is controlled at 60-90°C.

[0038] At the same time, in order to fully reduce the effective components in the washing residue, the mixed solution of the washing residue, concentrated sulfuric acid and reducing agent is stirred by a stirrer. The entire reduction acid leaching time is controlled within 2h-5h.

[0039] The reaction principle involved in heating reduction leaching of washing residue is: manganese dioxide reacts with sulfuric acid under the condition of reducing agent to generate manganese sulfate. The reaction equation is as follows:

[0040] MnO2+H2SO4+H2O2→MnSO4+H2O+O2↑

[0041] MnO2+SO2→MnSO4

[0042] MnO2+H2SO4+Na2SO3→MnSO4+H2O+Na2SO4

[0043] Step 3) After the reduction acid leaching of the washed residue is completed, solid-liquid separation is performed to obtain leached residue and leaching liquid. The leached residue can be further utilized as a building material.

[0044] The main component of the leaching solution is manganese sulfate, and it also contains trace amounts of impurities such as iron sulfate, calcium sulfate, magnesium sulfate, copper sulfate, zinc sulfate, nickel sulfate, and cobalt sulfate.

[0045] In order to provide data support for the amount of impurity remover added in the next step, so that an appropriate amount of impurity remover can be added to the leachate according to the amount of impurities in the leachate, to avoid insufficient impurity removal or excessive impurity remover causing waste, the leachate obtained by solid-liquid separation needs to be tested to detect the content of impurity metals in the leachate, that is, the content of impurity metals such as copper, zinc, iron, nickel and cobalt in the leachate.

[0046] Step 4) according to the content of impurity metals in the leachate, an appropriate amount of impurity remover is added to the leachate to remove impurities.

[0047] The impurity remover is one or more of manganese powder, sodium hydrosulfide and sodium carbonate. The impurities in the leachate are removed by chemical reaction between the impurity remover and the impurities to obtain a manganese sulfate solution with higher purity. The reaction principles involved in chemical impurity removal include: removing iron from the leachate by hydrolysis reaction, removing copper from the leachate by substitution reaction or sulfidation reaction of manganese powder, removing zinc from the leachate by sulfidation reaction, removing nickel and cobalt from the leachate by sulfidation reaction, etc.

[0048] After adding an appropriate amount of impurity remover to the leaching solution to complete the impurity removal reaction, the reaction mixture is subjected to solid-liquid separation to obtain impurity-removed slag and impurity-removed liquid. The impurity-removed slag is returned to the MHP high-acid leaching slag recovery system, and the effective components in the impurity-removed slag are further recovered.

[0049] Step 5) The impurity-removed liquid is first concentrated to a manganese concentration of about 120-150 g / L, and then the concentrated liquid is evaporated and crystallized to finally obtain crude manganese sulfate crystals. Since the main component of the impurity-removed liquid is manganese sulfate, of course, there are a small amount of other impurities, therefore, the impurity-removed liquid is evaporated and crystallized to obtain crude manganese sulfate crystals whose main component is manganese sulfate. Among them, the evaporation crystallization is a high-temperature thermal crystallization, and its evaporation crystallization temperature is controlled at 80-150°C.

[0050] Step 6) In order to further purify the crude manganese sulfate crystals, the crude manganese sulfate crystals are first dissolved in pure water to obtain a manganese sulfate solution, and then the manganese sulfate solution is concentrated. Finally, the concentrated solution is subjected to secondary crystallization to obtain high-purity manganese sulfate crystals, i.e., battery-grade manganese sulfate crystals.

[0051] Among them, the secondary crystallization is also high-temperature thermal crystallization, and its secondary crystallization temperature is controlled at 80-150°C.

[0052] The present invention provides a method for recovering manganese from MHP high-acid leaching residue. The method adopts a fully wet treatment method, and no dust is generated at the production site. The working environment conditions are good, the method is environmentally friendly, and the health impact on the workers is small. In addition, the method provided by the present invention does not require electrolysis, has low energy consumption, and relatively low acid and alkali consumption, so the production cost is low and the economic benefit is good.

[0053] The following is a detailed description of a method for recovering manganese from MHP high acid leaching residue provided by the present invention through examples.

[0054] The main components of the MHP high acid leaching residue used in the following examples of the present invention are shown in Table 1.

[0055] Table 1

[0056] Components Mn Ni Co Cu Zn Ca Mg Fe Al <![CDATA[H2O]]> content% 42.47 0.94 0.49 0.026 0.040 0.015 0.039 2.69 0.046 48.62

[0057] Example 1

[0058] a. Add 450ml of 20g / L dilute sulfuric acid solution and 300g of MHP high acid leaching residue to a 1000ml beaker, stir and wash in a water bath at constant temperature for 60min, then filter and perform operation b on the washed residue.

[0059] b. Add 100ml of water to a 500ml beaker, add 100g of washing residue, set up a water bath, set the temperature to 80℃, set up a stirrer, adjust its speed to 400rad to stir the mixture in the beaker, then slowly add 15ml of concentrated sulfuric acid to the beaker, then add 27.5% hydrogen peroxide to adjust the pH of the mixed solution in the beaker to 2.5; then add sulfuric acid to adjust the pH of the mixed solution to 1.0, then add hydrogen peroxide to adjust the pH of the mixed solution to 2.5, repeat the operation until the pH does not rise after adding hydrogen peroxide. A total of 50ml of sulfuric acid and 65ml of hydrogen peroxide are consumed, and the reaction is filtered after 30min, and the obtained leaching solution is subjected to operation c.

[0060] c. The leaching solution was tested for impurities such as Ni, Co, Cu, Zn, Fe, and Al. The test results are shown in Table 2.

[0061] Table 2

[0062] element Ni Co Cu Zn Fe Al Na Concentration g / L 1.68 0.89 0.06 0.08 4.88 0.08 0.32

[0063] d. Take 200 ml of the leachate and add it to a 500 ml beaker, place it in a 60°C water bath for heating and stirring, with a stirring speed of 400 rad, add 0.040 g of manganese powder, react for 90 min, then add 0.050 g of sodium hydrosulfide, react for 60 min, and filter to obtain the impurity-free liquid.

[0064] e. The obtained impurity-free liquid was concentrated to a manganese concentration of 150 g / L, and then maintained at 90°C for hot crystallization and filtration to obtain crude manganese sulfate crystals.

[0065] f. Take 100 g of crude manganese sulfate crystals and prepare 200 g / L manganese sulfate solution, perform hot crystallization and filtration at 80°C to obtain refined manganese sulfate crystals.

[0066] The metal element contents of the manganese sulfate crystals are shown in Table 3.

[0067] Table 3

[0068] Components Mn Cu Zn Ca Mg Fe Al Na Proportion% 32.23 Not detected Not detected 0.0020 0.0035 0.0002 0.0002 0.0013

[0069] It can be seen from Table 3 that the impurity metal element content of the manganese sulfate crystals obtained in the embodiment of the present invention is very low, that is, the manganese sulfate crystals obtained in the embodiment of the present invention have high purity and can fully meet the use requirements in the battery field.

[0070] Example 2

[0071] a. Add 450ml of 20g / L dilute sulfuric acid solution and 300g of MHP high acid leaching residue to a 1000ml beaker, stir in a water bath at a constant temperature for 60min and filter, and perform operation b on the washed residue.

[0072] b. Add 100ml of water to a 500ml beaker, add 100g of washing residue, set up a water bath, set the temperature to 80℃, set up a stirrer, adjust its speed to 400rad to stir the mixture in the beaker, slowly add 15ml of concentrated sulfuric acid to the beaker, then add hydrogen peroxide to adjust the pH to 2.5; then add sulfuric acid to adjust the pH to 1.0, then add 10% sodium pyrosulfite aqueous solution to adjust the pH to 2.5, repeat the operation until the pH does not rise after adding sodium pyrosulfite aqueous solution. A total of 49ml of sulfuric acid, 43ml of hydrogen peroxide, and 5.25g of sodium pyrosulfite are consumed, and the reaction is filtered after 30min, and the obtained leaching solution is subjected to operation c.

[0073] c. The leaching solution was tested for impurities such as Ni, Co, Cu, Zn, Fe, and Al. The test results are shown in Table 4.

[0074] Table 4

[0075] element Ni Co Cu Zn Fe Al Na Concentration g / L 1.58 0.85 0.06 0.08 4.95 0.07 0.32

[0076] d. Take 200 ml of the leachate and add it to a 500 ml beaker, place it in a 60°C water bath for heating and stirring, with a stirring speed of 400 rad, add 0.045 g of manganese powder, react for 90 min, then add 0.049 g of sodium hydrosulfide, react for 60 min, and filter to obtain the impurity-free liquid.

[0077] e. The obtained impurity-free liquid was concentrated to a manganese concentration of 150 g / L, and then maintained at 90°C for hot crystallization and filtration to obtain crude manganese sulfate crystals.

[0078] f. Take 100 g of crude manganese sulfate crystals and prepare 200 g / L manganese sulfate solution, perform hot crystallization and filtration at 120°C to obtain refined manganese sulfate crystals.

[0079] The metal element contents of the manganese sulfate crystals are shown in Table 5.

[0080] Table 5

[0081] Components Mn Cu Zn Ca Mg Fe Al Na Proportion% 32.32 Not detected Not detected 0.0022 0.0025 0.0002 0.0002 0.008

[0082] It can be seen from Table 5 that the impurity metal element content of the manganese sulfate crystals obtained in the embodiment of the present invention is very low, that is, the manganese sulfate crystals obtained in the embodiment of the present invention have high purity and can fully meet the use requirements in the battery field.

[0083] Example 3

[0084] a. Add 600ml of 20g / L dilute sulfuric acid solution, i.e. 300g of MHP high acid leaching residue, to a 1000ml beaker, stir in a water bath at a constant temperature for 60min and filter, and perform operation b on the washed residue.

[0085] b. Add 100ml of water to a 500ml beaker, add 100g of washing residue, set up a water bath, set the temperature to 80℃, set up a stirrer, and adjust its speed to 400rad, stir the mixture in the beaker, then slowly add 15ml of concentrated sulfuric acid to the beaker, then add hydrogen peroxide to adjust the pH to 2.5; then add sulfuric acid to adjust the pH to 1.0, then add hydrogen peroxide to adjust the pH to 2.5, repeat the operation until the pH does not rise after adding hydrogen peroxide. A total of 48ml of sulfuric acid and 65ml of hydrogen peroxide are consumed, and the reaction is filtered after 30min to obtain the leaching solution for operation c.

[0086] c. The leaching solution was tested for impurities such as Ni, Co, Cu, Zn, Fe, and Al. The test results are shown in Table 6.

[0087] Table 6

[0088] element Ni Co Cu Zn Fe Al Na Concentration g / L 1.28 0.78 0.05 0.07 4.62 0.06 0.29

[0089] d. Take 200 ml of the leachate and add it to a 500 ml beaker, place it in a 60°C water bath for heating and stirring, with a stirring speed of 400 rad, add 0.040 g of manganese powder, react for 90 min, then add 0.045 g of sodium hydrosulfide, react for 60 min, and filter to obtain the impurity-free liquid.

[0090] e. The obtained impurity-free liquid was concentrated to a manganese concentration of 150 g / L, and then maintained at 90°C for hot crystallization and filtration to obtain crude manganese sulfate crystals.

[0091] f. Take 100 g of crude manganese sulfate crystals and prepare 200 g / L manganese sulfate solution, perform hot crystallization and filtration at 90°C to obtain refined manganese sulfate crystals.

[0092] The metal element contents of the manganese sulfate crystals are shown in Table 7.

[0093] Table 7

[0094] Components Mn Cu Zn Ca Mg Fe Al Na Proportion% 32.42 Not detected Not detected 0.0020 0.0029 0.0002 0.0002 0.001

[0095] It can be seen from Table 7 that the impurity metal element content of the manganese sulfate crystals obtained in the embodiment of the present invention is very low, that is, the manganese sulfate crystals obtained in the embodiment of the present invention have high purity and can fully meet the use requirements in the battery field.

[0096] Embodiment 4:

[0097] a. Add 450ml of 20g / L dilute sulfuric acid solution (300gMHP) of high-acid leaching residue to a 1000ml beaker, stir in a water bath at constant temperature for 60min, filter, and perform operation b on the washed residue.

[0098] b. Add 100 ml of water to a 500 ml beaker, add 100 g of manganese slag, set up a water bath, set the temperature to 80 ° C, set up an agitator and adjust its speed to 400 rad to stir the mixture in the beaker, slowly add 15 ml of concentrated sulfuric acid to the beaker, and at the same time, introduce sulfur dioxide gas at 0.4 L / min. During the period, observe the pH change, add sulfuric acid to maintain pH 1.5-2.0, and after 25 minutes, the slurry changes from black to gray-black. Without adding sulfuric acid, the pH begins to decrease. A total of 25 ml of sulfuric acid is consumed. After reacting for 30 minutes, filter it and perform operation c on the obtained leaching solution.

[0099] c. The leaching solution was tested for impurities such as Ni, Co, Cu, Zn, Fe, and Al. The test results are shown in Table 8.

[0100] Table 8

[0101] element Ni Co Cu Zn Fe Al Na Concentration g / L 1.66 0.90 0.06 0.08 4.91 0.07 0.28

[0102] d. Take 200 ml of the leachate and add it to a 500 ml beaker, place it in a 60°C water bath for heating and stirring, with a stirring speed of 400 rad, add 0.045 g of manganese powder, react for 90 min, then add 0.051 g of sodium hydrosulfide, react for 60 min, and filter to obtain the impurity-free liquid.

[0103] e. The obtained impurity-free liquid was concentrated to a manganese concentration of 150 g / L, and then maintained at 90°C for hot crystallization and filtration to obtain crude manganese sulfate crystals.

[0104] f. Take 100 g of crude manganese sulfate crystals and prepare 200 g / L manganese sulfate solution, perform hot crystallization and filtration at 150°C to obtain refined manganese sulfate crystals.

[0105] The contents of metal elements in the manganese sulfate crystals are shown in Table 9.

[0106] Table 9

[0107] Components Mn Cu Zn Ca Mg Fe Al Na Proportion% 32.29 Not detected Not detected 0.0024 0.0026 0.0002 0.0002 0.007

[0108] It can be seen from Table 9 that the impurity metal element content of the manganese sulfate crystals obtained in the embodiment of the present invention is very low, that is, the manganese sulfate crystals obtained in the embodiment of the present invention have high purity and can fully meet the use requirements in the battery field.

[0109] Finally, it should be noted that the above specific implementation methods are only used to illustrate the technical solution of the present invention rather than to limit it. Although the present invention has been described in detail with reference to examples, those skilled in the art should understand that the technical solution of the present invention can be modified or replaced by equivalents without departing from the spirit and scope of the technical solution of the present invention, which should be included in the scope of the claims of the present invention.

Claims

1. A method for recovering manganese from MHP high acid leaching residue, characterized in that: The steps include: Washing the MHP high acid leaching residue with dilute sulfuric acid to obtain washing residue; Add concentrated sulfuric acid and a reducing agent to the washing residue for heating reduction acid leaching; After the reduction acid leaching is completed, the solid-liquid separation is performed to obtain the leachate, and the impurity metal content in the leachate is detected; According to the content of impurity metals in the leaching solution, an impurity remover is added to the leaching solution to remove impurities and obtain a de-impurity liquid; After impurities are removed, the liquid is evaporated and crystallized to obtain crude manganese sulfate crystals; The crude manganese sulfate crystals are dissolved and secondary crystallized to obtain high-purity manganese sulfate crystals.

2. The method for recovering manganese from MHP high acid leaching residue according to claim 1, characterized in that: The mixture of the dilute sulfuric acid and the MHP high-acid leaching residue is heated at a constant temperature in a water bath pot at a temperature of 60-90° C., and the mixture of the dilute sulfuric acid and the MHP high-acid leaching residue is continuously stirred by a stirrer.

3. The method for recovering manganese from MHP high acid leaching residue according to claim 2, characterized in that: The washing time of the MHP high-acid leaching residue with the dilute sulfuric acid is 40 min-80 min, and the concentration of the dilute sulfuric acid is not less than 20 g / L.

4. The method for recovering manganese from MHP high acid leaching residue according to claim 1, characterized in that: The washing residue is added with concentrated sulfuric acid and a reducing agent for heating and reduction acid leaching in a water bath, the heating temperature is 60-90° C., and the reduction acid leaching time is 2h-5h.

5. The method for recovering manganese from MHP high acid leaching residue according to claim 4, characterized in that: The reducing agent is one or more of hydrogen peroxide, sodium pyrosulfite and sulfur dioxide, and the pH of the mixed solution of the washing residue, concentrated sulfuric acid and the reducing agent is finally controlled at 2.0-3.

0.

6. The method for recovering manganese from MHP high acid leaching residue according to claim 5, characterized in that: The mixed solution of the washing residue, concentrated sulfuric acid and reducing agent is subjected to reduction acid leaching under the stirring of a stirrer.

7. The method for recovering manganese from MHP high acid leaching residue according to claim 1, characterized in that: The detection of the impurity metal content is the detection of copper, zinc, iron, nickel and cobalt in the leaching solution.

8. The method for recovering manganese from MHP high acid leaching residue according to claim 1, characterized in that: The impurity remover is one or more of manganese powder, sodium hydrosulfide and sodium carbonate.

9. The method for recovering manganese from MHP high acid leaching residue according to claim 1, characterized in that: The evaporative crystallization and secondary crystallization are high-temperature thermal crystallizations, and the crystallization temperature is controlled at 80-150°C.

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