Method for recycling decalcified magnesium in preparation of high-purity manganese sulfate from rhodochrosite

Abstract

The invention discloses a method for cyclic utilization of decalcified magnesium in preparation of high-purity manganese sulfate from rhodochrosite. The method for cyclic utilization of decalcified magnesium in preparation of high-purity manganese sulfate from rhodochrosite mainly comprises ten procedures of first acid leaching, precipitation, roasting, wet ball-milling leaching, second acid leaching, manganese extraction, manganese back extraction, neutralization, mixing and defluorination. Compared with the prior art, the method for cyclic utilization of decalcified magnesium in preparation of high-purity manganese sulfate from rhodochrosite lays a foundation for preparation of high-purity manganese sulfate, realizes reuse of a no-load organic phase and cyclic utilization of manganese fluoride, reduces generation of waste liquid in the technological process, and realizes sustainable utilization of resources.

Description

Technical Field

[0001] The invention relates to the technical field of mineral processing, and in particular to a method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite. Background Art

[0002] With the popularization of new energy vehicles and the rapid development of various electronic products, the demand and consumption of high-purity manganese sulfate as a precursor for the synthesis of positive electrode materials for lithium-ion batteries have increased year by year. The calcium and magnesium impurities associated with rhodochrosite are high in content and difficult to remove, resulting in about 60% of the world's manganese sulfate being processed from pyrolusite. The energy and material consumption in the electrolytic manganese production process is high, and the pollutant emissions are huge. Therefore, the study of green, efficient and low-consumption manganese ore enhanced extraction methods is of great strategic significance for alleviating the shortage of manganese ore resources in my country and promoting the healthy and sustainable development of the electrolytic manganese industry.

[0003] An invention patent discloses a method for preparing high-purity manganese sulfate with manganese carbonate ore powder and the product obtained therefrom. First, manganese carbonate ore powder is mixed with coal powder in a certain ratio and calcined; sulfuric acid is then added to stir the reaction, and a manganese sulfate solution is obtained by filtering; then an impurity remover MnF2 is added to the manganese sulfate solution, and the calcium and magnesium ions are precipitated and removed by adjusting the pH value and filtered, and an impurity remover MnS is added to the manganese sulfate filtrate, and the potassium and sodium ions are removed and filtered by adjusting the pH value, and an impurity remover FeF3 is added to the manganese sulfate filtrate, and the calcium, magnesium, potassium, and sodium ions are further precipitated and removed and filtered by adjusting the pH value; finally, the manganese sulfate solution after impurity removal is concentrated, the filtrate is allowed to stand for crystallization, and filtered to obtain a high-purity manganese sulfate product. However, the method includes complex calcination and impurity removal steps, and the production cost is very high. Most of the current technologies are to process rhodochrosite to prepare manganese sulfate, ignoring the calcium and magnesium content in rhodochrosite, and not making resource utilization of it.

[0004] Therefore, how to provide a method for recycling decalcified magnesium in the preparation of high-purity manganese sulfate from rhodochrosite, which is simple to operate, can effectively separate calcium and magnesium to facilitate the preparation of high-purity manganese sulfate, and at the same time realize the reuse of the unloaded organic phase and manganese fluoride, and the resource utilization of calcium and magnesium, so as to achieve the technical effect of promoting the recycling of resources, is a technical problem that technical personnel in this field urgently need to solve. Summary of the invention

[0005] In view of the problems existing in the prior art, the technical problem to be solved by the present invention is to provide a method for recycling decalcified magnesium in the preparation of high-purity manganese sulfate from rhodochrosite, which facilitates the preparation of high-purity manganese sulfate by acid leaching and precipitation decalcified magnesium, while realizing the reuse of the unloaded organic phase and manganese fluoride and the resource utilization of calcium and magnesium, thereby achieving the technical effect of promoting the recycling of resources.

[0006] To achieve the above-mentioned purpose, the present invention provides a method for recycling decalcified magnesium in the preparation of high-purity manganese sulfate from rhodochrosite, the method comprising: S1, first acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution; S2, precipitation: adding manganese fluoride to the first acid leaching solution obtained in S1, stirring and precipitating, and separating the solid and liquid to obtain calcium-magnesium slag and decalcified magnesium mixed solution; S3, roasting: adding sodium carbonate to the calcium-magnesium slag obtained in S2, mixing evenly, and then roasting to obtain roasted slag; S4, wet ball milling leaching: wet ball milling leaching the roasted slag obtained in S3, solid-liquid separation, to obtain leached slag and leaching solution; S5, second acid leaching: acid leaching the leached slag obtained in S4 with an aqueous sulfuric acid solution, solid-liquid separation, to obtain acid leaching slag and a second acid leaching solution; S6, Manganese extraction: the second acid leaching liquid obtained in S5 is subjected to manganese extraction to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase; S7, manganese back-extraction: the manganese-loaded organic phase obtained in S6 is subjected to sulfuric acid back-extraction to obtain an empty manganese organic phase and a manganese sulfate solution, and the empty manganese organic phase is reused in the manganese extraction process in S6; S8, neutralization: the leaching liquid obtained in S4 is neutralized with hydrofluoric acid to obtain a neutralized liquid; S9, mixing: the manganese sulfate solution obtained in S7 and the neutralized liquid obtained in S8 are mixed, solid-liquid separation is performed, manganese fluoride and a first mixed liquid are obtained, and the manganese fluoride is reused in the precipitation process in S2; S10, defluorination: the first mixed liquid obtained in S9 is mixed with the magnesium sulfate raffinate obtained in S6 for defluorination treatment to obtain magnesium fluoride and a defluorinated mixed liquid.

[0007] In the first aspect, in S1, the amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar amount of calcium and magnesium in rhodochrosite, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

[0008] In the first aspect, in S2, the amount of manganese fluoride added is 1.2 to 1.6 times the theoretical reaction molar ratio of calcium to magnesium in the first acid leaching solution, the stirring speed is 200 to 400 rpm, the precipitation time is 0.2 to 2 hours, and the precipitation temperature is 25 to 50°C.

[0009] In the first aspect, the decalcified magnesium mixed solution obtained in S2 is used to prepare high-purity manganese sulfate.

[0010] In the first aspect, in S3, the amount of sodium carbonate is 1.5 to 2 times the theoretical reaction molar ratio of calcium to magnesium in the calcium-magnesium slag, the roasting time is 2 to 6 hours, and the roasting temperature is 400 to 700°C.

[0011] In the first aspect, in S4, the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 6 to 12, the liquid-to-solid ratio of the wet ball milling leaching is 4 to 8 mL / g, the ball milling time of the wet ball milling leaching is 1 to 2 hours, and the ball milling speed of the wet ball milling leaching is 100 to 300 rpm.

[0012] In the first aspect, in S5, the molar amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar ratio of calcium to magnesium in the leached residue, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the leached residue is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

[0013] In the first aspect, in S6, the extractant is phosphorus tetroxide, the extraction O / A ratio is 1:1 to 1:5, the extraction temperature is 20 to 40° C., and the extraction time is 1 to 5 minutes.

[0014] In the first aspect, in S7, the stripping agent is a sulfuric acid aqueous solution with a concentration of 1 to 3 mol / L, the stripping O / A ratio is 5:1 to 1:1, the stripping temperature is 20 to 40°C, and the stripping time is 1 to 5 minutes.

[0015] In the first aspect, in S5, the leached residue is centrally treated; in S10, the defluorinated mixed liquor is centrally treated.

[0016] Beneficial effects:

[0017] The invention discloses a method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, comprising the steps of acid leaching the rhodochrosite with a sulfuric acid aqueous solution to obtain a first acid leaching solution comprising manganese ions, calcium ions, magnesium ions and carbonate ions, and then adding an excess of manganese fluoride to the first acid leaching solution to precipitate as many calcium ions and magnesium ions as possible to generate calcium fluoride precipitates and magnesium fluoride precipitates, wherein the calcium-magnesium slag comprises unreacted manganese fluoride, calcium fluoride and magnesium fluoride, and the decalcified magnesium mixed solution contains a large amount of sulfate ions and manganese ions, so that the decalcified magnesium mixed solution can be used to prepare high-purity manganese sulfate, thereby laying a foundation for preparing high-purity manganese sulfate; sodium carbonate is added to the calcium-magnesium slag and roasted at 400-700°C, and the sodium carbonate and the fluoride are reacted to form a reaction mixture; the reaction mixture is stirred for 3 hours and the reaction is continued for 1 hr; the reaction mixture is stirred for 2 hours and the reaction is continued for 3 hours; the reaction mixture is stirred for 3 hours and the reaction is continued for 4 ... Calcium generates calcium carbonate, sodium carbonate and magnesium fluoride finally obtain magnesium oxide and sodium fluoride, manganese fluoride and sodium carbonate finally obtain manganese oxide and sodium fluoride, and the roasting slag includes sodium carbonate, magnesium oxide, manganese oxide, sodium fluoride and sodium carbonate; water is used as the leaching solvent to perform wet ball milling leaching on the roasting slag. During the ball milling process, magnesium oxide is converted into magnesium hydroxide, and the particle size of calcium carbonate is smaller. The leached slag includes magnesium hydroxide, manganese oxide and calcium carbonate, and the leachate includes fluoride ions, sodium ions and carbonate ions. Hydrofluoric acid is added to the leachate for neutralization, and the obtained neutralized solution includes fluoride ions and sodium ions; the leached slag is acid-leached with a sulfuric acid aqueous solution, calcium carbonate reacts with sulfuric acid to generate calcium sulfate, magnesium hydroxide reacts with sulfuric acid to generate calcium sulfate, The reaction generates magnesium sulfate, and manganese oxide reacts with sulfuric acid to generate manganese sulfate. The obtained acid leaching residue includes calcium sulfate. Centralized treatment of the acid leaching residue facilitates resource utilization of calcium. The second acid leaching solution includes magnesium ions, manganese ions and sulfate ions. Phosphorus tetroxide is used as an extractant and sulfonated kerosene is used as a diluent to extract manganese from the second acid leaching solution to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase, wherein the magnesium sulfate raffinate is an inorganic phase, the magnesium sulfate raffinate includes magnesium ions and sulfate ions, and the manganese-loaded organic phase includes manganese ions. The manganese-loaded organic phase is stripped using an aqueous sulfuric acid solution as a stripping agent, and the aqueous sulfuric acid solution is used as an inorganic phase to strip the manganese ions, so that the manganese ions Manganese sulfate is obtained by reacting with sulfate ions, and the manganese-loaded organic phase is changed into an unloaded manganese organic phase. The unloaded manganese organic phase is directly reused in the manganese extraction process, so as to realize the reuse of the unloaded manganese organic phase and reduce the generation of waste liquid in the process; the manganese sulfate obtained in the manganese stripping process is mixed with the neutralization liquid, and the manganese ions and fluoride ions are used to obtain manganese fluoride and sodium sulfate, and the manganese fluoride is reused in the precipitation process of the first acid leaching solution, so as to realize the sustainable utilization of resources; the mixed solution includes fluoride ions, sodium ions and sulfate ions, and the mixed solution is mixed with the magnesium sulfate extraction solution, and the magnesium ions and fluoride ions are used to generate magnesium fluoride precipitation, and the fluoride ions are removed to obtain a defluorination solution, and the obtained magnesium fluoride can be used in other processes, so as to realize the resource utilization of magnesium.In summary, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite of the present invention is through acid leaching and precipitation. After decalcifying and magnesiumizing the rhodochrosite, the obtained decalcified magnesium mixed solution contains a large amount of manganese ions, so that the decalcified magnesium mixed solution can be used to prepare high-purity manganese sulfate, laying a foundation for the preparation of high-purity manganese sulfate; at the same time, the unloaded organic phase is reused in the process, reducing the generation of waste liquid in the process; in addition, the manganese fluoride prepared in the process can be reused to the precipitation stage of the first acid leaching solution, realizing the sustainable utilization of resources; the acid leaching residue and magnesium fluoride obtained in the process can be used in other processes, realizing the resource utilization of calcium and magnesium. BRIEF DESCRIPTION OF THE DRAWINGS

[0018] In order to more clearly illustrate the embodiments of this specification or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0019] Figure 1 This is a process diagram of a method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite of the present invention. DETAILED DESCRIPTION

[0020] The following will be combined with the drawings in the embodiments of this specification to clearly and completely describe the technical solutions in the embodiments of this specification. Obviously, the described embodiments are only part of the embodiments of this specification, not all of the embodiments. Based on the embodiments in this specification, all other embodiments obtained by ordinary technicians in this field belong to the scope of protection of the present invention.

[0021] Embodiment 1

[0022] like Figure 1As shown, the present embodiment 1 provides a method for recycling decalcified magnesium in the preparation of high-purity manganese sulfate from rhodochrosite, the method comprising: S1, first acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution; S2, precipitation: adding manganese fluoride to the first acid leaching solution obtained in S1, stirring and precipitating, solid-liquid separation, to obtain calcium-magnesium slag and decalcified magnesium mixed solution; S3, roasting: adding sodium carbonate to the calcium-magnesium slag obtained in S2, mixing evenly, and then roasting to obtain roasting slag; S4, wet ball milling leaching: wet ball milling leaching the roasting slag obtained in S3, solid-liquid separation, to obtain leached slag and leaching solution; S5, second acid leaching: acid leaching the leached slag obtained in S4 with an aqueous sulfuric acid solution, solid-liquid separation, to obtain acid leaching slag and a second acid leaching solution; S6, manganese Extraction: the second acid leaching liquid obtained in S5 is subjected to manganese extraction to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase; S7, manganese stripping: the manganese-loaded organic phase obtained in S6 is stripped with sulfuric acid to obtain an empty manganese organic phase and a manganese sulfate solution, and the empty manganese organic phase is reused in the manganese extraction process in S6; S8, neutralization: the leaching liquid obtained in S4 is neutralized with hydrofluoric acid to obtain a neutralized liquid; S9, mixing: the manganese sulfate solution obtained in S7 and the neutralized liquid obtained in S8 are mixed, solid-liquid separation is performed, manganese fluoride and a first mixed liquid are obtained, and the manganese fluoride is reused in the precipitation process in S2; S10, defluorination: the first mixed liquid obtained in S9 is mixed with the magnesium sulfate raffinate obtained in S6 for defluorination treatment to obtain magnesium fluoride and a defluorinated mixed liquid.

[0023] The invention discloses a method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, comprising the steps of acid leaching the rhodochrosite with a sulfuric acid aqueous solution to obtain a first acid leaching solution comprising manganese ions, calcium ions, magnesium ions and carbonate ions, and then adding an excess of manganese fluoride to the first acid leaching solution to precipitate as many calcium ions and magnesium ions as possible to generate calcium fluoride precipitates and magnesium fluoride precipitates, wherein the calcium-magnesium slag comprises unreacted manganese fluoride, calcium fluoride and magnesium fluoride, and the decalcified magnesium mixed solution contains a large amount of sulfate ions and manganese ions, so that the decalcified magnesium mixed solution can be used to prepare high-purity manganese sulfate, thereby laying a foundation for preparing high-purity manganese sulfate; sodium carbonate is added to the calcium-magnesium slag and roasted at 400-700°C, and the sodium carbonate and the fluoride are reacted to form a reaction mixture; the reaction mixture is stirred for 3 hours and the reaction is continued for 1 hr; the reaction mixture is stirred for 2 hours and the reaction is continued for 3 hours; the reaction mixture is stirred for 3 hours and the reaction is continued for 4 ... Calcium generates calcium carbonate, sodium carbonate and magnesium fluoride finally obtain magnesium oxide and sodium fluoride, manganese fluoride and sodium carbonate finally obtain manganese oxide and sodium fluoride, and the roasting slag includes sodium carbonate, magnesium oxide, manganese oxide, sodium fluoride and sodium carbonate; water is used as the leaching solvent to perform wet ball milling leaching on the roasting slag. During the ball milling process, magnesium oxide is converted into magnesium hydroxide, and the particle size of calcium carbonate is smaller. The leached slag includes magnesium hydroxide, manganese oxide and calcium carbonate, and the leachate includes fluoride ions, sodium ions and carbonate ions. Hydrofluoric acid is added to the leachate for neutralization, and the obtained neutralized solution includes fluoride ions and sodium ions; the leached slag is acid-leached with a sulfuric acid aqueous solution, calcium carbonate reacts with sulfuric acid to generate calcium sulfate, magnesium hydroxide reacts with sulfuric acid to generate calcium sulfate, The reaction generates magnesium sulfate, and manganese oxide reacts with sulfuric acid to generate manganese sulfate. The obtained acid leaching residue includes calcium sulfate. Centralized treatment of the acid leaching residue facilitates resource utilization of calcium. The second acid leaching solution includes magnesium ions, manganese ions and sulfate ions. Phosphorus tetroxide is used as an extractant and sulfonated kerosene is used as a diluent to extract manganese from the second acid leaching solution to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase, wherein the magnesium sulfate raffinate is an inorganic phase, the magnesium sulfate raffinate includes magnesium ions and sulfate ions, and the manganese-loaded organic phase includes manganese ions. The manganese-loaded organic phase is stripped using an aqueous sulfuric acid solution as a stripping agent, and the aqueous sulfuric acid solution is used as an inorganic phase to strip the manganese ions, so that the manganese ions Manganese sulfate is obtained by reacting with sulfate ions, and the manganese-loaded organic phase is changed into an unloaded manganese organic phase. The unloaded manganese organic phase is directly reused in the manganese extraction process, so as to realize the reuse of the unloaded manganese organic phase and reduce the generation of waste liquid in the process; the manganese sulfate obtained in the manganese stripping process is mixed with the neutralization liquid, and the manganese ions and fluoride ions are used to obtain manganese fluoride and sodium sulfate, and the manganese fluoride is reused in the precipitation process of the first acid leaching solution, so as to realize the sustainable utilization of resources; the mixed solution includes fluoride ions, sodium ions and sulfate ions, and the mixed solution is mixed with the magnesium sulfate extraction solution, and the magnesium ions and fluoride ions are used to generate magnesium fluoride precipitation, and the fluoride ions are removed to obtain a defluorination solution, and the obtained magnesium fluoride can be used in other processes, so as to realize the resource utilization of magnesium.In summary, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite of the present invention is through acid leaching and precipitation. After decalcifying and magnesiumizing the rhodochrosite, the obtained decalcified magnesium mixed solution contains a large amount of manganese ions, so that the decalcified magnesium mixed solution can be used to prepare high-purity manganese sulfate, laying a foundation for the preparation of high-purity manganese sulfate; at the same time, the unloaded organic phase is reused in the process, reducing the generation of waste liquid in the process; in addition, the manganese fluoride prepared in the process can be reused to the precipitation stage of the first acid leaching solution, realizing the sustainable utilization of resources; the acid leaching residue and magnesium fluoride obtained in the process can be used in other processes, realizing the resource utilization of calcium and magnesium.

[0024] In some possible implementations, in S1, the amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar amount of calcium and magnesium in rhodochrosite, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

[0025] Specifically, rhodochrosite contains a large amount of calcium and magnesium ions. The calcium, magnesium and manganese ions are dissolved through acid leaching, which facilitates the subsequent precipitation of calcium and magnesium ions using manganese fluoride.

[0026] In some possible implementations, in S2, the amount of manganese fluoride added is 1.2 to 1.6 times the theoretical reaction molar ratio of calcium to magnesium in the first acid leaching solution, the stirring speed is 200 to 400 rpm, the precipitation time is 0.2 to 2 hours, and the precipitation temperature is 25 to 50°C.

[0027] Specifically, the excess manganese fluoride relative to calcium and magnesium ions can precipitate as many calcium and magnesium ions in the first acid leaching solution as possible to generate calcium fluoride precipitate and magnesium fluoride precipitate, and the calcium-magnesium slag includes unreacted manganese fluoride, calcium fluoride and magnesium fluoride.

[0028] In some possible implementations, the decalcified magnesium mixed solution obtained in S2 is used to prepare high-purity manganese sulfate.

[0029] Specifically, the decalcified magnesium mixed solution contains a large amount of manganese ions and sulfate ions, so that high-purity manganese sulfate can be prepared from the decalcified magnesium mixed solution.

[0030] In some possible implementations, in S3, the amount of sodium carbonate is 1.5 to 2 times the theoretical reaction molar ratio of calcium to magnesium in the calcium-magnesium slag, the roasting time is 2 to 6 hours, and the roasting temperature is 400 to 700°C.

[0031] Specifically, under the calcination condition of 400-700° C., sodium carbonate and calcium fluoride obtain calcium carbonate, sodium carbonate and magnesium fluoride obtain magnesium oxide, sodium carbonate and manganese fluoride obtain manganese oxide, and the unreacted calcium carbonate does not decompose.

[0032] In some possible implementations, in S4, the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 6-12, the liquid-to-solid ratio of the wet ball milling leaching is 4-8 mL / g, the ball milling time of the wet ball milling leaching is 1-2 hours, and the ball milling speed of the wet ball milling leaching is 100-300 rpm.

[0033] Specifically, in wet ball milling leaching, the solvent is water, sodium carbonate and sodium fluoride are dissolved in water, magnesium oxide reacts with water during the ball milling process to form magnesium hydroxide, and calcium carbonate becomes a solid with very small particle size. The leaching residue includes magnesium hydroxide, manganese oxide and calcium carbonate, and the leaching liquid includes sodium carbonate and sodium fluoride.

[0034] In some possible implementations, in S5, the molar amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar ratio of calcium to magnesium in the leached residue, the liquid-solid ratio of the aqueous sulfuric acid solution to the leached residue is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

[0035] Specifically, during the acid leaching process, small-particle calcium carbonate reacts with a sulfuric acid aqueous solution to generate calcium sulfate precipitate, magnesium hydroxide reacts with a sulfuric acid aqueous solution to generate magnesium sulfate and water, and manganese oxide reacts with a sulfuric acid aqueous solution to generate manganese sulfate and water; the acid leaching residue includes calcium carbonate precipitate and calcium sulfate precipitate; the second acid leaching solution includes sulfate ions, manganese ions and magnesium ions.

[0036] In some possible implementations, in S6, the extractant is phosphorus tetroxide, the extraction O / A ratio is 1:1 to 1:5, the extraction temperature is 20 to 40° C., and the extraction time is 1 to 5 minutes.

[0037] Specifically, phosphorus tetroxide uses sulfonated kerosene as a diluent in the manganese extraction step. In the manganese extraction step, manganese ions in the second acid leaching solution are extracted into the organic phase, and sulfate ions and magnesium ions are extracted into the inorganic phase, so that manganese ions are separated from magnesium ions.

[0038] In some possible implementations, in S7, the stripping agent is a sulfuric acid aqueous solution with a concentration of 1 to 3 mol / L, the stripping O / A ratio is 5:1 to 1:1, the stripping temperature is 20 to 40° C., and the stripping time is 1 to 5 minutes.

[0039] Specifically, the manganese stripping process allows manganese ions in the organic phase to separate from the organic phase and generate manganese sulfate with sulfuric acid. The manganese-free organic phase is reused in the manganese extraction process, thereby realizing the recycling of the manganese-free organic phase and reducing the generation of waste liquid in the process.

[0040] In some possible implementations, in S5, the leached residue is centrally processed; in S10, the defluorinated mixed liquor is centrally processed.

[0041] Specifically, centralized processing of leaching residue can realize resource utilization of calcium; centralized processing of defluorination solution can effectively protect environmental safety.

[0042] In order to further illustrate the technical solution of the present application in detail to support the technical problem to be solved by the present application, the preparation method is described below with specific examples, such as Examples 1 to 5.

[0043] Example 1

[0044] A method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite specifically comprising:

[0045] First acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution, wherein the amount of the aqueous sulfuric acid solution is 1.5 times the theoretical molar amount of calcium and magnesium in the rhodochrosite, the liquid-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 8 mL / g, the acid leaching time is 0.2 hours, and the acid leaching temperature is 25° C.;

[0046] Precipitation: adding manganese fluoride to the first acid leaching solution obtained above, stirring at a stirring speed of 200 rpm to generate precipitation, separating the solid and the liquid, and obtaining calcium-magnesium slag and a decalcified magnesium mixed solution, wherein the amount of manganese fluoride added is 1.2 times the theoretical reaction molar ratio of calcium and magnesium in the first acid leaching solution, the precipitation time is 0.2 hours, and the precipitation temperature is 25° C. The decalcified magnesium mixed solution is used to prepare high-purity manganese sulfate;

[0047] Calcination: adding sodium carbonate to the calcium-magnesium slag obtained above, mixing evenly, and then calcining to obtain calcined slag, wherein the amount of sodium carbonate is 1.5 times the theoretical reaction molar ratio of calcium and magnesium in the calcium-magnesium slag, the calcining time is 2 hours, and the calcining temperature is 700° C.;

[0048] Wet ball milling leaching: The calcined slag obtained above is subjected to wet ball milling leaching, and solid-liquid separation is performed to obtain leached slag and leaching liquid, wherein the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 12, the liquid-solid ratio of the wet ball milling leaching is 8 mL / g, the ball milling time of the wet ball milling leaching is 2 hours, and the ball milling speed of the wet ball milling leaching is 300 rpm;

[0049] Second acid leaching: acid leaching the leached residue obtained above with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and a second acid leaching solution, the molar amount of the sulfuric acid aqueous solution is twice the theoretical molar ratio of calcium and magnesium in the leached residue, the liquid-solid ratio of the sulfuric acid aqueous solution to the leached residue is 14 mL / g, the acid leaching time is 2 hours, and the acid leaching time is 50° C. The acid leached residue is centrally treated;

[0050] Manganese extraction: extract manganese from the second acid leaching solution obtained above to obtain magnesium sulfate raffinate and manganese-loaded organic phase, the extractant is phosphorus tetroxide, the extraction O / A phase ratio is 1:1, the extraction temperature is 20°C, the extraction time is 1 minute, and sulfonated kerosene is used as the dilution solvent;

[0051] Manganese stripping: The manganese-loaded organic phase obtained above is stripped with sulfuric acid to obtain an empty manganese organic phase and a manganese sulfate solution, and the empty manganese organic phase is reused in the manganese extraction step above, the stripping agent is a 3 mol / L sulfuric acid aqueous solution, the stripping O / A ratio is 1:1, the stripping temperature is 20° C., and the stripping time is 5 minutes;

[0052] Neutralization: neutralizing the above-obtained leaching solution with hydrofluoric acid to obtain a neutralized solution;

[0053] Mixing: mixing the manganese sulfate solution obtained above and the neutralized solution obtained above, separating the solid from the liquid to obtain manganese fluoride and a first mixed solution, wherein the manganese fluoride is recycled to the precipitation step;

[0054] Defluorination: the first mixed solution obtained above is mixed with the magnesium sulfate raffinate obtained above to carry out defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution; the defluorinated mixed solution is centrally treated.

[0055] Example 2

[0056] A method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite specifically comprising:

[0057] First acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution, wherein the amount of the aqueous sulfuric acid solution is 1.6 times the theoretical molar amount of calcium and magnesium in the rhodochrosite, the liquid-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 10 mL / g, the acid leaching time is 1 hour, and the acid leaching temperature is 30° C.;

[0058] Precipitation: adding manganese fluoride to the first acid leaching solution obtained above, stirring at a stirring speed of 400 rpm to generate precipitation, separating the solid and the liquid, and obtaining calcium-magnesium slag and a decalcified magnesium mixed solution, wherein the amount of manganese fluoride added is 1.6 times the theoretical reaction molar ratio of calcium and magnesium in the first acid leaching solution, the precipitation time is 2 hours, and the precipitation temperature is 50° C. The decalcified magnesium mixed solution is used to prepare high-purity manganese sulfate;

[0059] Calcination: adding sodium carbonate to the calcium-magnesium slag obtained above, mixing evenly, and then calcining to obtain calcined slag, wherein the amount of sodium carbonate is twice the theoretical reaction molar ratio of calcium and magnesium in the calcium-magnesium slag, the calcining time is 6 hours, and the calcining temperature is 700° C.;

[0060] Wet ball milling leaching: The calcined slag obtained above is subjected to wet ball milling leaching, and solid-liquid separation is performed to obtain leached slag and leaching liquid, wherein the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 12, the liquid-solid ratio of the wet ball milling leaching is 6 mL / g, the ball milling time of the wet ball milling leaching is 2 hours, and the ball milling speed of the wet ball milling leaching is 300 rpm;

[0061] Second acid leaching: acid leaching the leached residue obtained above with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and a second acid leaching solution, the molar amount of the sulfuric acid aqueous solution is 1.6 times the theoretical molar ratio of calcium and magnesium in the leached residue, the liquid-solid ratio of the sulfuric acid aqueous solution to the leached residue is 10 mL / g, the acid leaching time is 1.2 hours, and the acid leaching time is 40° C. The acid leached residue is centrally treated;

[0062] Manganese extraction: extract manganese from the second acid leaching solution obtained above to obtain magnesium sulfate raffinate and manganese-loaded organic phase, the extractant is phosphorus tetroxide, the extraction O / A phase ratio is 1:5, the extraction temperature is 40°C, the extraction time is 5 minutes, and sulfonated kerosene is used as the dilution solvent;

[0063] Manganese stripping: subjecting the manganese-loaded organic phase obtained above to sulfuric acid stripping to obtain an unloaded manganese organic phase and a manganese sulfate solution, and recycling the unloaded manganese organic phase to the manganese extraction step, wherein the stripping agent is a 3 mol / L sulfuric acid aqueous solution, the stripping O / A phase ratio is 1:1, the stripping temperature is 20° C., and the stripping time is 5 minutes;

[0064] Neutralization: neutralizing the above-obtained leaching solution with hydrofluoric acid to obtain a neutralized solution;

[0065] Mixing: mixing the manganese sulfate solution obtained above and the neutralized solution obtained above, separating the solid from the liquid to obtain manganese fluoride and a first mixed solution, wherein the manganese fluoride is recycled to the precipitation step;

[0066] Defluorination: the first mixed solution obtained above is mixed with the magnesium sulfate raffinate obtained above to carry out defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution; the defluorinated mixed solution is centrally treated.

[0067] Example 3

[0068] A method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite specifically comprising:

[0069] First acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution, wherein the amount of the aqueous sulfuric acid solution is 1.7 times the theoretical molar amount of calcium and magnesium in the rhodochrosite, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 12 mL / g, the acid leaching time is 1.5 hours, and the acid leaching temperature is 40° C.;

[0070] Precipitation: adding manganese fluoride to the first acid leaching solution obtained above, stirring at a stirring speed of 300 rpm to generate precipitation, separating the solid and the liquid, and obtaining calcium-magnesium slag and a decalcified magnesium mixed solution, wherein the amount of manganese fluoride added is 1.3 times the theoretical reaction molar ratio of calcium and magnesium in the first acid leaching solution, the precipitation time is 1.2 hours, and the precipitation temperature is 40° C. The decalcified magnesium mixed solution is used to prepare high-purity manganese sulfate;

[0071] Calcination: adding sodium carbonate to the calcium-magnesium slag obtained above, mixing evenly, and then calcining to obtain calcined slag, wherein the amount of sodium carbonate is 1.8 times the theoretical reaction molar ratio of calcium and magnesium in the calcium-magnesium slag, the calcination time is 4 hours, and the calcination temperature is 600° C.;

[0072] Wet ball milling leaching: The calcined slag obtained above is subjected to wet ball milling leaching, and solid-liquid separation is performed to obtain leached slag and leaching liquid, wherein the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 8, the liquid-solid ratio of the wet ball milling leaching is 6 mL / g, the ball milling time of the wet ball milling leaching is 1.5 hours, and the ball milling speed of the wet ball milling leaching is 200 rpm;

[0073] Second acid leaching: acid leaching the leached residue obtained above with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and a second acid leaching solution, the molar amount of the sulfuric acid aqueous solution is twice the theoretical molar ratio of calcium and magnesium in the leached residue, the liquid-solid ratio of the sulfuric acid aqueous solution to the leached residue is 14 mL / g, the acid leaching time is 2 hours, and the acid leaching time is 50° C. The acid leached residue is centrally treated;

[0074] Manganese extraction: The second acid leaching solution obtained above is subjected to manganese extraction to obtain magnesium sulfate raffinate and manganese-loaded organic phase, the extractant is phosphorus tetroxide, the extraction O / A phase ratio is 1:3, the extraction temperature is 30°C, the extraction time is 3 minutes, and sulfonated kerosene is used as the dilution solvent;

[0075] Manganese stripping: subjecting the manganese-loaded organic phase obtained above to sulfuric acid stripping to obtain an unloaded manganese organic phase and a manganese sulfate solution, and recycling the unloaded manganese organic phase to the manganese extraction step, wherein the stripping agent is a 2 mol / L sulfuric acid aqueous solution, the stripping O / A phase ratio is 3:1, the stripping temperature is 35° C., and the stripping time is 3 minutes;

[0076] Neutralization: neutralizing the above-obtained leaching solution with hydrofluoric acid to obtain a neutralized solution;

[0077] Mixing: mixing the manganese sulfate solution obtained above and the neutralized solution obtained above, separating the solid from the liquid to obtain manganese fluoride and a first mixed solution, wherein the manganese fluoride is recycled to the precipitation step;

[0078] Defluorination: the first mixed solution obtained above is mixed with the magnesium sulfate raffinate obtained above to carry out defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution; the defluorinated mixed solution is centrally treated.

[0079] Example 4

[0080] A method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite specifically comprising:

[0081] First acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution, wherein the amount of the aqueous sulfuric acid solution is 1.8 times the theoretical molar amount of calcium and magnesium in the rhodochrosite, the liquid-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 10 mL / g, the acid leaching time is 2 hours, and the acid leaching temperature is 30° C.;

[0082] Precipitation: adding manganese fluoride to the first acid leaching solution obtained above, stirring at a stirring speed of 400 rpm to generate precipitation, separating the solid and the liquid, and obtaining calcium-magnesium slag and a decalcified magnesium mixed solution, wherein the amount of manganese fluoride added is 1.5 times the theoretical reaction molar ratio of calcium and magnesium in the first acid leaching solution, the precipitation time is 2 hours, and the precipitation temperature is 50° C. The decalcified magnesium mixed solution is used to prepare high-purity manganese sulfate;

[0083] Calcination: adding sodium carbonate to the calcium-magnesium slag obtained above, mixing evenly, and then calcining to obtain calcined slag, wherein the amount of sodium carbonate is twice the theoretical reaction molar ratio of calcium and magnesium in the calcium-magnesium slag, the calcining time is 6 hours, and the calcining temperature is 500° C.;

[0084] Wet ball milling leaching: The calcined slag obtained above is subjected to wet ball milling leaching, and solid-liquid separation is performed to obtain leached slag and leaching liquid, wherein the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 10, the liquid-solid ratio of the wet ball milling leaching is 6 mL / g, the ball milling time of the wet ball milling leaching is 1 hour, and the ball milling speed of the wet ball milling leaching is 200 rpm;

[0085] Second acid leaching: acid leaching the leached residue obtained above with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and a second acid leaching solution, the molar amount of the sulfuric acid aqueous solution is 1.8 times the theoretical molar ratio of calcium and magnesium in the leached residue, the liquid-solid ratio of the sulfuric acid aqueous solution to the leached residue is 12 mL / g, the acid leaching time is 1.5 hours, and the acid leaching temperature is 40° C. The acid leached residue is centrally treated;

[0086] Manganese extraction: The second acid leaching solution obtained above is subjected to manganese extraction to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase, the extractant is phosphorus tetroxide, the extraction O / A phase ratio is 1:4, the extraction temperature is 35°C, the extraction time is 4 minutes, and sulfonated kerosene is used as a dilution solvent;

[0087] Manganese stripping: subjecting the manganese-loaded organic phase obtained above to sulfuric acid stripping to obtain an unloaded manganese organic phase and a manganese sulfate solution, and recycling the unloaded manganese organic phase to the manganese extraction step, wherein the stripping agent is a 2.5 mol / L sulfuric acid aqueous solution, the stripping O / A phase ratio is 3:1, the stripping temperature is 30° C., and the stripping time is 4 minutes;

[0088] Neutralization: neutralizing the above-obtained leaching solution with hydrofluoric acid to obtain a neutralized solution;

[0089] Mixing: mixing the manganese sulfate solution obtained above and the neutralized solution obtained above, separating the solid from the liquid to obtain manganese fluoride and a first mixed solution, wherein the manganese fluoride is recycled to the precipitation step;

[0090] Defluorination: the first mixed solution obtained above is mixed with the magnesium sulfate raffinate obtained above to carry out defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution; the defluorinated mixed solution is centrally treated.

[0091] Example 5

[0092] A method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite, the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite specifically comprising:

[0093] First acid leaching: acid leaching the rhodochrosite with an aqueous sulfuric acid solution to obtain a first acid leaching solution, wherein the amount of the aqueous sulfuric acid solution is 1.9 times the theoretical molar amount of calcium and magnesium in the rhodochrosite, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 14 mL / g, the acid leaching time is 1.8 hours, and the acid leaching temperature is 50° C.;

[0094] Precipitation: adding manganese fluoride to the first acid leaching solution obtained above, stirring at a stirring speed of 400 rpm to generate precipitation, separating the solid and the liquid, and obtaining calcium-magnesium slag and a decalcified magnesium mixed solution, wherein the amount of manganese fluoride added is 1.6 times the theoretical reaction molar ratio of calcium and magnesium in the first acid leaching solution, the precipitation time is 2 hours, and the precipitation temperature is 50° C. The decalcified magnesium mixed solution is used to prepare high-purity manganese sulfate;

[0095] Calcination: adding sodium carbonate to the calcium-magnesium slag obtained above, mixing evenly, and then calcining to obtain calcined slag, wherein the amount of sodium carbonate is 1.9 times the theoretical reaction molar ratio of calcium and magnesium in the calcium-magnesium slag, the calcining time is 4 hours, and the calcining temperature is 600° C.;

[0096] Wet ball milling leaching: The calcined slag obtained above is subjected to wet ball milling leaching, and solid-liquid separation is performed to obtain leached slag and leaching liquid, wherein the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 10, the liquid-solid ratio of the wet ball milling leaching is 6 mL / g, the ball milling time of the wet ball milling leaching is 1.5 hours, and the ball milling speed of the wet ball milling leaching is 200 rpm;

[0097] Second acid leaching: acid leaching the leached residue obtained above with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and a second acid leaching solution, the molar amount of the sulfuric acid aqueous solution is 1.9 times the theoretical molar ratio of calcium and magnesium in the leached residue, the liquid-solid ratio of the sulfuric acid aqueous solution to the leached residue is 8 mL / g, the acid leaching time is 2 hours, the acid leaching temperature is 25°C; the acid leached residue is centrally treated;

[0098] Manganese extraction: extract manganese from the second acid leaching solution obtained above to obtain magnesium sulfate raffinate and manganese-loaded organic phase, the extractant is phosphorus tetroxide, the extraction O / A phase ratio is 1:2, the extraction temperature is 25°C, the extraction time is 2 minutes, and sulfonated kerosene is used as the dilution solvent;

[0099] Manganese stripping: subjecting the manganese-loaded organic phase obtained above to sulfuric acid stripping to obtain an unloaded manganese organic phase and a manganese sulfate solution, and the unloaded manganese organic phase is reused in the manganese extraction step above, the stripping agent is a 1.5 mol / L sulfuric acid aqueous solution, the stripping O / A phase ratio is 2:1, the stripping temperature is 20° C., and the stripping time is 2 minutes;

[0100] Neutralization: neutralizing the above-obtained leaching solution with hydrofluoric acid to obtain a neutralized solution;

[0101] Mixing: mixing the manganese sulfate solution obtained above and the neutralized solution obtained above, separating the solid from the liquid to obtain manganese fluoride and a first mixed solution, wherein the manganese fluoride is recycled to the precipitation step;

[0102] Defluorination: the first mixed solution obtained above is mixed with the magnesium sulfate raffinate obtained above to carry out defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution; the defluorinated mixed solution is centrally treated.

[0103] The concentrations of various ions in the decalcified magnesium mixed solution obtained from the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite in Examples 1 to 5 are compared as follows:

[0104] The test results of the concentrations of calcium ions, magnesium ions and manganese ions in the decalcified magnesium mixed solution are shown in Table 1.

[0105] Table 1 Concentrations of calcium ions, magnesium ions and manganese ions

[0106] Example Calcium ion concentration Magnesium ion concentration Manganese ion concentration Example 1 <80mg / L <85mg / L >35g / L Example 2 <77mg / L <80mg / L >35.5g / L Example 3 <73mg / L <78mg / L >36.3g / L Example 4 <69mg / L <72mg / L >37.6g / L Example 5 <65mg / L <72mg / L >38.5g / L

[0107] It can be seen from Table 1 that the manganese ion concentration in the decalcified magnesium mixed solution obtained in the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite of the present invention is greater than 35 g / L, the calcium ion concentration is less than 80 mg / L, and the magnesium ion concentration is less than 85 mg / L. It can be seen that the decalcified magnesium mixed solution in the method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite of the present invention contains a high concentration of manganese ions, which can be used to prepare high-purity manganese sulfate, laying a foundation for the preparation of high-purity manganese sulfate.

[0108] The preferred specific embodiments of the present invention are described in detail above. It should be understood that a person skilled in the art can make many modifications and changes based on the concept of the present invention without creative work. Therefore, any technical solution that can be obtained by a person skilled in the art through logical analysis, reasoning or limited experiments based on the concept of the present invention on the basis of the prior art should be within the scope of protection determined by the claims.

Claims

1. A method for recycling decalcified magnesium in the preparation of high-purity manganese sulfate from rhodochrosite, characterized in that: The method comprises: S1, first acid leaching: acid leaching the rhodochrosite with a sulfuric acid aqueous solution to obtain a first acid leaching solution; S2, precipitation: adding manganese fluoride to the first acid leaching solution obtained in S1, stirring and precipitating, and separating the solid and liquid to obtain calcium-magnesium slag and a decalcified magnesium mixed solution; S3, roasting: adding sodium carbonate to the calcium-magnesium slag obtained in S2, mixing evenly, and then roasting to obtain roasted slag; S4, wet ball milling leaching: wet ball milling leaching the roasted slag obtained in S3, solid-liquid separation, to obtain leached slag and leaching liquid; S5, second acid leaching: acid leaching the leached residue obtained in S4 with a sulfuric acid aqueous solution, solid-liquid separation, to obtain acid leached residue and second acid leaching liquid; S6, manganese extraction: extracting manganese from the second acid leaching solution obtained in S5 to obtain a magnesium sulfate raffinate and a manganese-loaded organic phase; S7, manganese stripping: subjecting the manganese-loaded organic phase obtained in S6 to sulfuric acid stripping to obtain an unloaded manganese organic phase and a manganese sulfate solution, and recycling the unloaded manganese organic phase to the manganese extraction step in S6; S8, neutralization: neutralizing the leachate obtained in S4 with hydrofluoric acid to obtain a neutralized solution; S9, mixing: mixing the manganese sulfate solution obtained in S7 and the neutralized solution obtained in S8, separating the solid and the liquid to obtain manganese fluoride and a first mixed solution, and the manganese fluoride is recycled to the precipitation step in S2; S10, defluorination: the first mixed solution obtained in S9 is mixed with the magnesium sulfate raffinate obtained in S6 to perform defluorination treatment to obtain magnesium fluoride and a defluorinated mixed solution.

2. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 1, characterized in that: In S1, the amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar amount of calcium and magnesium in rhodochrosite, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the rhodochrosite is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

3. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 2, characterized in that: In S2, the amount of manganese fluoride added is 1.2 to 1.6 times the theoretical reaction molar ratio of calcium to magnesium in the first acid leaching solution, the stirring speed is 200 to 400 rpm, the precipitation time is 0.2 to 2 hours, and the precipitation temperature is 25 to 50°C.

4. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 3, characterized in that: The decalcified magnesium mixed solution obtained in S2 is used to prepare high-purity manganese sulfate.

5. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 4, characterized in that: In S3, the amount of sodium carbonate is 1.5 to 2 times the theoretical reaction molar ratio of calcium to magnesium in the calcium-magnesium slag, the roasting time is 2 to 6 hours, and the roasting temperature is 400 to 700°C.

6. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 5, characterized in that: In S4, the leaching solvent of the wet ball milling leaching is water, the ball-to-material ratio of the wet ball milling leaching is 6-12, the liquid-to-solid ratio of the wet ball milling leaching is 4-8 mL / g, the ball milling time of the wet ball milling leaching is 1-2 hours, and the ball milling speed of the wet ball milling leaching is 100-300 rpm.

7. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 6, characterized in that: In S5, the molar amount of the aqueous sulfuric acid solution is 1.5 to 2 times the theoretical molar ratio of calcium to magnesium in the leached residue, the liquid-to-solid ratio of the aqueous sulfuric acid solution to the leached residue is 8 to 14 mL / g, the acid leaching time is 0.2 to 2 hours, and the acid leaching temperature is 25 to 50°C.

8. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 7, characterized in that: In S6, the extractant is phosphorus tetroxide, the extraction O / A ratio is 1:1 to 1:5, the extraction temperature is 20 to 40° C., and the extraction time is 1 to 5 minutes.

9. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 8, characterized in that: In S7, the stripping agent is a sulfuric acid aqueous solution with a concentration of 1 to 3 mol / L, the stripping O / A ratio is 5:1 to 1:1, the stripping temperature is 20 to 40° C., and the stripping time is 1 to 5 minutes.

10. The method for recycling decalcified magnesium in preparing high-purity manganese sulfate from rhodochrosite as claimed in claim 9, characterized in that: In S5, the acid leaching residue is centrally treated; in S10, the defluorination mixed liquid is centrally treated.

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