Preparation method of manganese carbonate

Abstract

The invention relates to the technical field of hydrometallurgy, in particular to a preparation method of manganese carbonate. The preparation method of the manganese carbonate comprises the following steps: in the presence of a solvent, mixing a manganese source with SO2, and taking a liquid phase; mixing the liquid phase with carbonic acid and / or CO2, taking a solid phase, and drying to obtain manganese carbonate; and in the liquid phase, the concentration of Mn < 2 + > is 130-150g / L. According to the method disclosed by the invention, the pure wet process is utilized, the introduction of a large amount of impurity ions such as Na < + > and NH4 < + > can be avoided by utilizing the carbonic acid and / or CO2 to prepare the manganese carbonate, the manganese carbonate product with higher product purity can be prepared, and the separation of impurity elements and manganese elements is realized.

Description

Technical Field

[0001] The invention relates to the technical field of hydrometallurgy, and in particular to a method for preparing manganese carbonate. Background Art

[0002] At present, 85% of the zinc smelting industry is hydrometallurgical zinc smelting. During the electrolytic process of hydrometallurgical zinc smelting, manganese-containing slag with manganese dioxide, lead sulfate, lead dioxide and silver compounds as the main components will be produced. The traditional treatment method is to directly return it to the leaching process for reuse or directly to the lead smelting system for treatment and recovery of lead and silver. However, there are problems such as low metal recovery rate, manganese ions in the system solution affecting zinc electrolysis or manganese ions cannot be effectively recovered, resulting in the inability to recycle manganese resources. The current common method is to use a reducing agent (sulfurizing agent or sulfur dioxide) to reduce the Mn in the manganese-containing slag of hydrometallurgical zinc smelting. 4+ Reduction to Mn 2+ , and then the manganese sulfate solution is purified and impurities removed (removing potassium, sodium, calcium, magnesium and heavy metals) to prepare manganese sulfate products, which are widely used in high-tech industries such as electronics, medicine, dyes, and ceramics. However, with the rapid development of the new energy industry, the demand for manganese carbonate, one of the raw materials for battery positive electrode ternary materials, has increased, and the quality requirements have become increasingly higher.

[0003] Therefore, it is urgent to develop a method for preparing manganese carbonate with higher product purity. Summary of the invention

[0004] The present invention aims to solve one of the technical problems in the related art at least to a certain extent. To this end, the object of the present invention is to provide a method for preparing manganese carbonate, which can prepare a manganese carbonate product with higher purity.

[0005] To this end, the present invention provides a method for preparing manganese carbonate, comprising the following steps:

[0006] In the presence of a solvent, a manganese source is mixed with SO2 to obtain a liquid phase; the liquid phase is mixed with carbonic acid and / or CO2, a solid phase is obtained, and dried to obtain manganese carbonate;

[0007] In the liquid phase, Mn 2+ The concentration is 130-150g / L.

[0008] The present invention utilizes a pure wet process to prepare manganese carbonate using carbonic acid and / or CO2, thereby achieving the goal of eliminating a large amount of Na + NH4 + The introduction of impurity ions can not only produce manganese carbonate products with higher purity, but also achieve the separation of impurity elements and manganese elements.

[0009] In some embodiments of the present invention, the temperature of the liquid phase and carbonic acid and / or CO2 is 45-55°C and the time is 30-60 minutes. If the reaction temperature is too high, energy costs and equipment losses will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove.

[0010] In some embodiments of the present invention, the partial pressure of SO2 is 0.1-0.2 MPa. Controlling the partial pressure of SO2 can ensure the leaching effect of manganese and reduce the tail gas residue.

[0011] In some embodiments of the present invention, the temperature of the manganese source and SO2 is 25-30°C and the time is 1-2 hours. If the reaction temperature is too high, energy costs and equipment losses will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove.

[0012] In some embodiments of the present invention, the liquid phase is decontaminated before being mixed with carbonic acid and / or CO2; the decontamination includes a heavy metal removal treatment and a calcium and magnesium removal treatment performed sequentially.

[0013] In some embodiments of the present invention, the heavy metal removal treatment comprises: mixing the liquid phase with a sulfiding agent to obtain a heavy metal removal liquid.

[0014] In some embodiments of the present invention, the calcium and magnesium removal treatment includes: mixing the heavy metal removal solution with manganese fluoride to obtain a calcium and magnesium removal solution.

[0015] In some embodiments of the present invention, the temperature of the mixture of the liquid phase and the sulfiding agent is 45-55° C. and the time is 2-3 hours. If the reaction temperature is too high, the energy cost and equipment loss will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove.

[0016] In some embodiments of the present invention, the molar ratio of the heavy metal ions and the sulfiding agent in the liquid phase is 1:(1-2); the sulfiding agent includes at least one of manganese sulfide, barium sulfide or H2S.

[0017] In some embodiments of the present invention, the temperature of the mixture of the heavy metal removal liquid and the manganese fluoride is 80-90°C for 1-3 hours. If the reaction temperature is too high, the energy cost and equipment loss will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove.

[0018] In some embodiments of the present invention, the ratio of the amount of calcium ions and magnesium ions in the heavy metal removal solution to the amount of manganese fluoride is 1:(1-2).

[0019] In some embodiments of the present invention, the drying temperature is 110-130° C. and the drying time is 1-4 hours.

[0020] Additional aspects and advantages of the present invention will be given in part in the following description and in part will be obvious from the following description, or will be learned through practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] The above and / or additional aspects and advantages of the present invention will become apparent and easily understood from the description of the embodiments in conjunction with the following drawings, in which:

[0022] Figure 1 The process flow chart of the method for preparing manganese carbonate according to Example 1 of the present invention is shown. DETAILED DESCRIPTION

[0023] The embodiments of the present invention are described in detail below. The embodiments described below are exemplary and are only used to explain the present invention, and should not be understood as limiting the present invention.

[0024] It should be noted that the terms "first" and "second" are used for descriptive purposes only and should not be understood as indicating or implying relative importance or implicitly indicating the number of the indicated technical features. Therefore, the features defined as "first" and "second" may explicitly or implicitly include one or more of the features. Further, in the description of the present invention, unless otherwise specified, the meaning of "plurality" is two or more.

[0025] The present invention provides a method for preparing manganese carbonate, comprising the following steps:

[0026] In the presence of a solvent, a manganese source is mixed with SO2 to obtain a liquid phase; the liquid phase is mixed with carbonic acid and / or CO2, a solid phase is obtained, and dried to obtain manganese carbonate;

[0027] In the liquid phase, Mn 2+ The concentration is 130-150g / L.

[0028] The present invention utilizes a pure wet process to prepare manganese carbonate using carbonic acid and / or CO2, thereby achieving the goal of eliminating a large amount of Na + NH4 + The introduction of impurity ions can not only produce manganese carbonate products with higher purity, but also achieve the separation of impurity elements and manganese elements.

[0029] In some embodiments of the present invention, the manganese source includes industrial manganese-containing slag; the industrial manganese-containing slag includes hydrometallurgical manganese-containing slag; the hydrometallurgical manganese-containing slag contains 40% to 42% Mn.

[0030] In some embodiments of the invention, the solvent comprises water.

[0031] As an example, in the liquid phase, Mn 2+ The concentration can be 130, 132, 135, 138, 140, 142, 145, 147 or 150 g / L.

[0032] In some embodiments of the present invention, the liquid-to-solid ratio of the manganese source to the solvent is (3-5):1 L / g; in other preferred embodiments of the present invention, the liquid-to-solid ratio of the manganese source to the solvent is 3:1, 3.5:1, 4:1, 4.5:1, or 5:1 L / g.

[0033] In some embodiments of the present invention, the partial pressure of SO2 is 0.1-0.2 MPa. As an example, the partial pressure of SO2 can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or 0.2 MPa. In some preferred embodiments of the present invention, the partial pressure of SO2 is 0.1 MPa. Controlling the partial pressure of SO2 can ensure the leaching effect of manganese and reduce the tail gas residue.

[0034] In some embodiments of the present invention, the molar ratio of Mn to SO2 in the manganese source is 1:(1-2). The molar ratio of Mn to SO2 in the manganese source may be 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0035] In some embodiments of the present invention, the temperature at which the manganese source is mixed with SO2 is 25 to 30°C, and the time is 1 to 2 hours; in some preferred embodiments of the present invention, the temperature at which the manganese source is mixed with SO2 is 25°C, and the reaction time is 1 to 1.2 hours. If the reaction temperature is too high, energy costs and equipment losses will increase, and if the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove. As an example, the temperature at which the manganese source is mixed with SO2 may be 25, 26, 27, 28, 29 or 30°C. As an example, the time for mixing the manganese source with SO2 may be 1, 1.1, 1.2, 1.3, 1.4, 1.5, 1.6, 1.7, 1.8, 1.9 or 2 hours.

[0036] In some embodiments of the present invention, a manganese source is mixed with SO2 in the presence of a solvent to perform reduction leaching. The chemical reaction of this process is as follows:

[0037] SO2+MnO2+H2O→MnSO4·H2O

[0038] In some embodiments of the present invention, the manganese source and SO2 are mixed under stirring conditions; the stirring speed is 400-600r / min.

[0039] In some embodiments of the present invention, after the manganese source and SO2 are mixed and reacted, the system is preferably filtered to obtain a filter residue and a liquid phase.

[0040] In some embodiments of the present invention, the liquid phase is decontaminated before being mixed with carbonic acid and / or CO2; the decontamination includes a heavy metal removal treatment and a calcium and magnesium removal treatment performed sequentially.

[0041] In some embodiments of the present invention, the heavy metal removal treatment includes: mixing the liquid phase with a sulfiding agent to obtain a heavy metal removal liquid; the calcium and magnesium removal treatment includes: mixing the heavy metal removal liquid with manganese fluoride to obtain a calcium and magnesium removal liquid.

[0042] In some embodiments of the present invention, the temperature of the mixture of the liquid phase and the vulcanizing agent is 45 to 55 ° C, and the time is 2 to 3 hours; in other preferred embodiments of the present invention, the temperature of the mixture of the liquid phase and the vulcanizing agent is 45 ° C. If the reaction temperature is too high, energy costs and equipment losses will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove. As an example, the temperature of the mixture of the liquid phase and the vulcanizing agent can be 45, 46, 47, 48, 49, 50, 51, 52, 53, 54 or 55 ° C. As an example, the time of mixing the liquid phase and the vulcanizing agent can be 2, 2.1, 2.2, 2.3, 2.4, 4, 2.5, 2.6, 2.7, 2.8, 2.9 or 3 hours.

[0043] In some embodiments of the present invention, the ratio of the amount of heavy metal ions in the liquid phase to the amount of the sulfiding agent is 1:(1-2); the sulfiding agent includes at least one of manganese sulfide, barium sulfide or H2S. As an example, the ratio of the amount of heavy metal ions in the liquid phase to the amount of the sulfiding agent can be 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0044] In some embodiments of the present invention, the partial pressure of H2S is ≤0.1 MPa; in other preferred embodiments of the present invention, the partial pressure of H2S is ≤0.05 MPa. Controlling the partial pressure of the gas can further remove heavy metal ions in the solution.

[0045] In some embodiments of the present invention, the liquid phase contains a variety of heavy metal impurities, including but not limited to lead ions, silver ions, zinc ions, copper ions and cadmium ions; when the sulfiding agent is H2S, the chemical reaction of heavy metal removal treatment is as follows:

[0046] H2S+(Pb,Zn,Cu,Cd) 2+ →(Pb,Zn,Cu,Cd)S↓+H +

[0047] In some embodiments of the present invention, after the liquid phase and H2S are mixed, the system is preferentially filtered to obtain sulfided slag and heavy metal removal liquid.

[0048] In some embodiments of the present invention, the temperature of the mixture of the heavy metal removal liquid and manganese fluoride is 80-90°C for 1-3 hours; in other preferred embodiments of the present invention, the temperature of the mixture of the heavy metal removal liquid and manganese fluoride is 80°C for 1.5-2 hours. If the reaction temperature is too high, the energy cost and equipment loss will increase. If the reaction temperature is too low, the reaction will be incomplete and impurities will be difficult to completely remove.

[0049] In some embodiments of the present invention, the ratio of the amount of the substance of calcium ions and magnesium ions in the heavy metal removal solution to the amount of the substance of manganese fluoride is 1:(1-2). As an example, the ratio of the amount of the substance of calcium ions and magnesium ions in the heavy metal removal solution to the amount of the substance of manganese fluoride can be 1:1, 1:1.2, 1:1.5, 1:1.6, 1:1.8, or 1:2.

[0050] In some embodiments of the present invention, the chemical reaction of the calcium and magnesium removal treatment is as follows:

[0051] MnF2+Ca 2+ →CaF2↓+Mn 2+

[0052] MnF2+Mg 2+ →MgF2↓+Mn 2+

[0053] In some embodiments of the present invention, after the liquid phase and H2S are mixed, the system is preferably filtered to obtain calcium-magnesium slag and calcium-magnesium removal liquid; and the pH of the calcium-magnesium removal liquid is controlled to be greater than 4.5. Controlling the solution pH can further improve the removal rate of calcium ions and magnesium ions.

[0054] In some embodiments of the present invention, after the decalcification and magnesium treatment, a decalcification and magnesium liquid is obtained, the pH of the decalcification and magnesium liquid is adjusted to 6.0-6.5, and mixed with carbonic acid and / or CO2; the mixing is preferably carried out under stirring conditions; the stirring speed is 100-150r / min; the mixing temperature is 45-55°C, and the time is 30-60min; in other preferred embodiments of the present invention, the mixing temperature is 45°C, and the time is 45min. If the reaction temperature is too high, it will increase energy costs and equipment losses. If the reaction temperature is too low, it will lead to incomplete reaction and impurities will be difficult to completely remove. The use of carbonic acid and / or CO2 to prepare manganese carbonate can achieve a large amount of Na + NH4 +The impurity ions are introduced, and the purity of the manganese carbonate product is higher. As an example, the mixing temperature can be 45, 46, 47, 48, 49, 50, 51, 52, 53, 54 or 55° C., and the mixing time can be 30, 35, 40, 45, 50, 55 or 60 minutes.

[0055] In some other preferred embodiments of the present invention, the decalcified magnesium solution is mixed with CO2; the partial pressure of the CO2 is 0.1-0.2 MPa. Controlling the partial pressure of the gas can ensure that there is sufficient CO2 in the solution to react to form carbonic acid, which then reacts with manganese ions after ionization. As an example, the partial pressure of CO2 can be 0.1, 0.11, 0.12, 0.13, 0.14, 0.15, 0.16, 0.17, 0.18, 0.19 or 0.2 MPa.

[0056] In some embodiments of the present invention, before mixing the decalcification and magnesium liquid with carbonic acid and / or CO2, the pH of the decalcification and magnesium liquid is adjusted to 4.8-5.5; preferably, the pH of the decalcification and magnesium liquid is adjusted with an alkaline substance; the alkaline substance includes at least one of calcium hydroxide, ammonium carbonate, ammonium bicarbonate or ammonia water.

[0057] In some embodiments of the present invention, the chemical reaction after the calcium and magnesium removal solution is mixed with CO2 is as follows:

[0058] CO2+H2O→H2CO3

[0059]

[0060]

[0061]

[0062] In some embodiments of the present invention, after the calcium-magnesium removal liquid is mixed with carbonic acid and / or CO2, the solid-liquid separation is performed, the solid phase is a manganese carbonate filter cake, and the liquid phase is a carbonate mixed solution containing potassium and sodium; the solid phase is dried; the drying temperature is 110-130°C and the time is 1-4 hours; in some other preferred embodiments of the present invention, the drying temperature is 120°C and the time is 2 hours. The present invention makes full use of the sodium element in the manganese source, and potassium salt and sodium salt are obtained after treatment, thereby saving resources.

[0063] In some embodiments of the present invention, the method for preparing manganese carbonate further comprises: washing the solid phase with water for multiple times before drying the solid phase, thereby reducing the content of impurity ions in the solid phase and further improving the purity of the manganese carbonate product.

[0064] The scheme of the present disclosure will be explained below in conjunction with the examples. Those skilled in the art will appreciate that the following examples are only used to illustrate the present disclosure and should not be considered to limit the scope of the present disclosure. Where specific techniques or conditions are not indicated in the examples, the techniques or conditions described in the literature in this area or the product instructions are used. Where the manufacturers of reagents or instruments are not indicated, they are all conventional products that can be obtained commercially.

[0065] The manganese source used in the embodiments of the present invention and the comparative examples is the manganese-containing slag from the wet zinc smelting process after water washing, and the chemical composition table is shown in Table 1.

[0066] Table 1 Content of metal elements in manganese-containing slag from zinc smelting %

[0067] element Mn Pb Mg Ag Zn Ca Cl K Na Before washing 40.15 4.18 0.068 0.0152 1.56 0.82 0.015 1.44 0.025 After washing 41.06 4.11 0.058 0.0156 1.54 0.89 0.011 1.46 0.024

[0068] Example 1

[0069] The preparation method of manganese carbonate in this embodiment has a process flow as follows: Figure 1 As shown, the specific steps include:

[0070] (1) Reduction leaching: The washed hydrometallurgical manganese-containing slag was mixed with water at a liquid-solid ratio of 3:1 L / g at room temperature, added into an autoclave, and then SO2 gas was introduced and its partial pressure was adjusted to 0.1 MPa. The stirring speed was controlled to 400 r / min, and the reaction was carried out for 1 hour. The solid-liquid separation was carried out to obtain lead-silver slag and reduction leaching solution. The lead-silver slag contained 33.56wt% Pb and 1212g / t Ag. The reduction leaching solution contained 20.37wt% Mn and 15.7wt% Ag. 2+ The concentration is 145g / L; among them, the molar ratio of Mn and SO2 in the manganese-containing slag of wet zinc smelting after water washing is 1:1.2.

[0071] (2) Removal of heavy metals: H2S gas is introduced into the reduction leaching solution obtained in step (1) at 45°C, the H2S partial pressure is 0.05 MPa, the molar ratio of heavy metal ions to H2S is 1:1.5, the reaction is carried out for 2 hours, and the solid-liquid separation is performed to obtain a heavy metal removal solution and sulfide slag.

[0072] (3) Removing calcium and magnesium: The heavy metal removal liquid obtained in step (2) is heated to 80° C., manganese fluoride is added, and the ratio of the amount of calcium ions and magnesium ions in the heavy metal removal liquid to the amount of manganese fluoride is 1:1.6. The pH of the system is adjusted to 5.0 with limestone milk, and the reaction is carried out for 1.8 hours. The calcium and magnesium slag and the calcium and magnesium removal liquid are separated by solid-liquid separation.

[0073] (4) Evaporation and crystallization: The pH of the decalcified and magnesium-removing solution obtained in step (3) was adjusted to 6.0 with sodium hydroxide, and then transferred into an autoclave, CO2 was introduced and its partial pressure was controlled to 0.1 MPa, the reaction temperature was adjusted to 45°C, the stirring speed was 150 r / min, and the solid-liquid separation was performed after 45 minutes of reaction to obtain a manganese carbonate filter cake and a carbonate mixed solution containing potassium and sodium (potassium-sodium mixed solution). The manganese carbonate filter cake was washed with deionized water for several times and then dried at 120°C for 2 hours to finally obtain a manganese carbonate product, the composition of which is shown in Table 2. As can be seen from Table 2, the manganese carbonate obtained by the method of this embodiment has a manganese content of up to 41.91%, which fully meets the requirements of HG / T 4023-2011.

[0074] Table 2 Manganese carbonate composition %

[0075] element Mn Fe Cl <![CDATA[SO4 2- ]]> Pb Cu Cd As Hg content 41.91 0.091 0.035 0.45 0.0065 0.002 0.0015 0.0005 0.0005

[0076] Example 2

[0077] The method for preparing manganese carbonate of this embodiment comprises the following steps:

[0078] (1) Reduction leaching: The washed hydrometallurgical manganese-containing slag was mixed with water at a liquid-to-solid ratio of 4:1 L / g at room temperature, added into an autoclave, and SO2 gas was introduced and its partial pressure was adjusted to 0.1 MPa. The stirring speed was controlled to 400 r / min, and the reaction was carried out for 1.1 h. The solid-liquid separation was carried out to obtain lead-silver slag and reduction leaching solution. The lead-silver slag contained 35.72% Pb and 1500 g / t Ag. The reduction leaching solution contained 20.3% Mn and 15.6% Mn. 2+ The concentration is 141g / L; among them, the molar ratio of Mn and SO2 in the manganese-containing slag of wet zinc smelting after water washing is 1:1.2.

[0079] (2) Removal of heavy metals: H2S was added to the reduction leaching solution obtained in step (1) at 45°C, the H2S partial pressure was 0.05 MPa, the molar ratio of heavy metal ions to H2S was 1:1.3, the reaction was continued for 3 hours, and the heavy metal removal solution and sulfide slag were obtained by solid-liquid separation.

[0080] (3) Removing calcium and magnesium: The heavy metal removal liquid obtained in step (2) is heated to 80° C. and then manganese fluoride is added. The ratio of the amount of calcium ions and magnesium ions in the heavy metal removal liquid to the amount of manganese fluoride is 1:1.8. The pH value is adjusted to 4.8 with limestone milk. The reaction is carried out for 2 hours. The solid-liquid separation is performed to obtain calcium-magnesium slag and calcium-magnesium removal liquid.

[0081] (4) Evaporation and crystallization: add alkali to adjust the pH of the calcium and magnesium removal solution obtained in step (3) to 6.3, transfer it into an autoclave, introduce CO2 and control its partial pressure to 0.13MPa, control the reaction temperature to 45°C, stir at 150r / min, react for 45min, separate the solid and liquid, obtain a manganese carbonate filter cake and a carbonate solution containing potassium and sodium, wash the manganese carbonate filter cake with deionized water for several times and dry it at 120°C for 2h, and finally obtain a manganese carbonate product, the composition of which is shown in Table 3. As shown in Table 3, the manganese carbonate obtained by the method of this embodiment has a manganese content of up to 41.61%, which fully meets the requirements of HG / T 4023-2011.

[0082] Table 3 Manganese carbonate composition %

[0083] element Mn Fe Cl <![CDATA[SO4 2- ]]> Pb Cu Cd As Hg content 41.61 0.089 0.032 0.35 0.006 0.0021 0.0016 0.0005 0.0005

[0084] Example 3

[0085] The method for preparing manganese carbonate of this embodiment comprises the following steps:

[0086] (1) Reduction leaching: The washed hydrometallurgical manganese-containing zinc slag was mixed with water at a liquid-solid ratio of 5:1 L / g at room temperature and added into an autoclave. After passing SO2 gas, its partial pressure was adjusted to 0.1 MPa. The stirring speed was controlled to 400 r / min. The reaction was carried out for 1.2 h. The solid-liquid separation was carried out to obtain lead-silver slag and reduction leaching solution. The lead-silver slag contained 37.79% Pb and 1201 g / t Ag. The reduction leaching solution contained 20.3 g / t Mn. 2+ The concentration is 130g / L; among them, the molar ratio of Mn and SO2 in the manganese-containing slag of wet zinc smelting after water washing is 1:1.2.

[0087] (2) Removal of heavy metals: H2S gas is introduced into the reduction leaching solution obtained in step (1) at 45°C, the H2S partial pressure is 0.05 MPa, the molar ratio of heavy metal ions to H2S is 1:1.3, the reaction is carried out for 3 hours, and the solid-liquid separation is performed to obtain a heavy metal removal solution and sulfide slag.

[0088] (3) Removing calcium and magnesium: The heavy metal removal liquid obtained in step (2) is heated to 80° C., manganese fluoride is added, and the ratio of the amount of calcium ions and magnesium ions in the heavy metal removal liquid to the amount of manganese fluoride is 1:1.6. The pH value is adjusted to 5.2 with limestone milk, and the reaction is carried out for 3 hours. The calcium and magnesium slag and the calcium and magnesium removal liquid are separated by solid-liquid separation.

[0089] (4) Evaporation and crystallization: add alkali to adjust the pH of the calcium and magnesium removal solution obtained in step (3) to 6.2, transfer it into an autoclave, introduce CO2 and control its partial pressure to 0.15MPa, control the reaction temperature to 45°C, stir at 150r / min, react for 45min, separate the solid and liquid, obtain a manganese carbonate filter cake and a carbonate solution containing potassium and sodium, wash the manganese carbonate filter cake with deionized water for several times and dry it at 120°C for 2h, and finally obtain a manganese carbonate product, the composition of which is shown in Table 4. As can be seen from Table 4, the manganese carbonate obtained by the method of this embodiment has a manganese content of up to 42.11%, which fully meets the requirements of HG / T 4023-2011.

[0090] Table 4 Manganese carbonate composition %

[0091] element Mn Fe Cl <![CDATA[SO4 2- ]]> Pb Cu Cd As Hg content 42.11 0.08 0.037 0.44 0.0063 0.0018 0.0012 0.0005 0.0005

[0092] Comparative Example 1

[0093] The preparation method of manganese carbonate in this comparative example is different from that in Example 1 only in that CO2 is replaced by ammonium bicarbonate in this comparative example, the ratio of the amount of manganese ions in the calcium and magnesium removal solution to the amount of ammonium bicarbonate is controlled to be 1:1.5, and the remaining steps are carried out with reference to the method in Example 1. The manganese content in the manganese carbonate obtained in this comparative example is relatively low, at 36.72%.

[0094] Comparative Example 2

[0095] The preparation method of manganese carbonate in this comparative example is different from that in Example 1 only in that the partial pressure of SO2 is adjusted to 0.25 MPa in this comparative example, and the remaining steps are carried out in accordance with the method in Example 1. The manganese content in the manganese carbonate obtained in this comparative example is relatively low, at 30.43%.

[0096] In the description of this specification, the description with reference to the terms "one embodiment", "some embodiments", "example", "specific example", "some implementation schemes" or "some examples" etc. means that the specific features, structures, materials or characteristics described in conjunction with the embodiment or example are included in at least one embodiment or example of the present invention. In this specification, the schematic representations of the above terms do not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials or characteristics described may be combined in any one or more embodiments or examples in a suitable manner. In addition, those skilled in the art may combine and combine the different embodiments or examples described in this specification and the features of the different embodiments or examples, unless they are contradictory.

[0097] Although the embodiments of the present invention have been shown and described above, it is to be understood that the above embodiments are exemplary and are not to be construed as limitations of the present invention. A person skilled in the art may change, modify, replace and vary the above embodiments within the scope of the present invention.

Claims

1. A method for preparing manganese carbonate, characterized in that: The following steps are involved: In the presence of a solvent, a manganese source is mixed with SO2 to obtain a liquid phase; the liquid phase is mixed with carbonic acid and / or CO2, a solid phase is obtained, and dried to obtain manganese carbonate; In the liquid phase, Mn 2+ The concentration is 130-150g / L.

2. The method for preparing manganese carbonate according to claim 1, characterized in that: The temperature of the mixing of the liquid phase with carbonic acid and / or CO2 is 45-55°C and the time is 30-60 minutes.

3. The method for preparing manganese carbonate according to claim 1, characterized in that: The partial pressure of SO2 is 0.1-0.2 MPa.

4. The method for preparing manganese carbonate according to claim 1, characterized in that: The manganese source and SO2 are mixed at a temperature of 25 to 30°C for 1 to 2 hours.

5. The method for preparing manganese carbonate according to claim 1, characterized in that: Before the liquid phase is mixed with carbonic acid and / or CO2, the liquid phase is subjected to impurity removal; the impurity removal includes heavy metal removal treatment and calcium and magnesium removal treatment performed in sequence.

6. The method for preparing manganese carbonate according to claim 5, characterized in that: The heavy metal removal treatment comprises: mixing the liquid phase with a sulfiding agent to obtain a heavy metal removal liquid; The calcium and magnesium removal treatment comprises: mixing the heavy metal removal solution with manganese fluoride to obtain a calcium and magnesium removal solution.

7. The method for preparing manganese carbonate according to claim 6, characterized in that: The temperature of the mixing of the liquid phase and the vulcanizing agent is 45-55° C. and the time is 2-3 hours.

8. The method for preparing manganese carbonate according to claim 6, characterized in that: The ratio of the amount of heavy metal ions and the amount of sulfiding agent in the liquid phase is 1:(1-2); the sulfiding agent includes at least one of manganese sulfide, barium sulfide or H2S.

9. The method for preparing manganese carbonate according to claim 6, characterized in that: The temperature of the heavy metal removal solution and manganese fluoride is 80-90° C. and the time is 1-3 hours; and / or, The ratio of the amount of calcium ions and magnesium ions in the heavy metal removal solution to the amount of manganese fluoride is 1:(1-2).

10. The method for preparing manganese carbonate according to claim 1, characterized in that: The drying temperature is 110-130° C. and the drying time is 1-4 hours.

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