Method for preparing manganese sulfate crystal and manganous-manganic oxide by using manganese carbonate ore

Abstract

The invention discloses a method for preparing a manganese sulfate crystal by using manganese carbonate ore. The preparation method of the manganese sulfate crystal comprises the following steps: leaching manganese carbonate ore by using sulfuric acid to obtain a leaching solution, precipitating the leaching solution by using a heavy removing agent to remove heavy metal ions, neutralizing redundant sulfuric acid in the leaching solution, introducing a precipitating agent, reacting with the precipitating agent to obtain a precipitate, washing the precipitate with water to remove impurities, and dissolving by using sulfuric acid to obtain the manganese sulfate crystal. And after dissolving, precipitating a small amount of residual calcium and magnesium ions by using fluoride, filtering to obtain fluorine-containing manganese sulfate filtrate, finally adding a fluorine removal agent for solid-liquid separation, and evaporating and crystallizing the filtrate to obtain manganese sulfate crystals. The manganese sulfate crystal is suitable for production of a lithium ion battery positive electrode material. According to the preparation method of the manganese sulfate crystal, the impurity removal cost is greatly reduced. The invention also discloses a method for preparing manganous-manganic oxide from manganese carbonate ore. The tap density of the manganous-manganic oxide is greater than 2.3 g / cm < 3 >, the specific surface area is less than 3m < 2 > / g, and the requirement of a battery-grade material is met.

Description

Technical Field

[0001] The invention relates to the technical field of nonferrous metal hydrometallurgy, and in particular to a method for preparing manganese sulfate crystals and manganese tetraoxide by utilizing manganese carbonate ore. Background Art

[0002] Manganese is one of the most widely used elements in positive electrode materials. It has considerable development potential due to its non-toxicity, low cost, and large capacity. High-purity manganese sulfate is the main synthetic salt of ternary lithium, lithium manganate, and lithium iron manganese phosphate positive electrode materials. Therefore, the industrial preparation of high-purity manganese sulfate plays a great role in promoting the development of the new energy industry. However, since battery-grade manganese sulfate has very strict requirements on impurity content, impurities such as calcium, magnesium, potassium, sodium, and heavy metals that have a greater impact on the performance of lithium-ion batteries must be strictly controlled.

[0003] my country's manganese ore is mainly low-grade manganese ore, the main component of which is manganese carbonate, which is low-grade and complex in composition. Therefore, the existing manganese sulfate industry is highly dependent on imported high-grade manganese ore (manganese oxide ore). With the increasing market demand for manganese sulfate, it is of great significance to rationally and efficiently develop and utilize domestic low-grade manganese ore (manganese carbonate ore) to prepare high-purity manganese sulfate.

[0004] At present, the existing technology utilizes manganese carbonate ore with complex composition, and it is difficult to remove impurities using manganese carbonate ore in the existing technology, the purification effect is not good, and it contains more impurities. Summary of the invention

[0005] In view of the above problems, the main purpose of the present invention is to solve the technical problem of more impurities in preparing battery-grade manganese sulfate using manganese carbonate ore in the prior art.

[0006] To achieve the above object, the specific technical solution of the present invention is:

[0007] A method for preparing manganese sulfate crystals using manganese carbonate ore comprises the following steps:

[0008] After the manganese carbonate ore is pulped, sulfuric acid is added for leaching and an oxidant is added to obtain a leaching solution;

[0009] The leachate is added with a de-heaving agent according to 1.1-1.2 times the amount of the heavy metal substance, and filtered after a preset reaction time, and a neutralizing agent is added to the filtered filtrate to control the pH to 4.5-5.5, and then filtered to obtain a manganese sulfate solution;

[0010] The manganese sulfate solution and the precipitant are subjected to a precipitation reaction under the condition of pH 6-7.5, and the precipitate is washed by slurrying with hot water after filtering to obtain a washed precipitate;

[0011] The washed precipitate is dissolved in sulfuric acid, manganese fluoride is added in a fluorine-calcium molar ratio of 2.2-2.4:1, and then filtered, and a defluorinating agent is added to the filtered filtrate in an amount of 3-10 times the mass of the fluorine solute, and then filtered and evaporated to obtain the manganese sulfate crystals.

[0012] Preferably, the liquid-to-solid ratio of the manganese carbonate ore slurry is 4-6:1, the leaching temperature of adding sulfuric acid after slurrying is 60-80°C, and the leaching time is 4h.

[0013] Preferably, the oxidant is any one or more of air, oxygen, ozone, and hydrogen peroxide, and the sulfide is any one or more of (NH4)2S, Na2S, K2S, and NaSH.

[0014] Preferably, the step of slurrying the manganese carbonate ore, adding sulfuric acid for leaching and adding an oxidant to obtain a leachate comprises:

[0015] The manganese carbonate ore is pulped and then sulfuric acid is added for leaching to obtain an initial leaching solution;

[0016] Manganese carbonate ore is added to the initial leaching solution to prepare ore pulp, and then sulfuric acid is added to leach again to obtain the leaching solution, wherein the manganese concentration of the leaching solution is in the range of 80-140 g / L.

[0017] Preferably, the step of adding 1.1-1.2 times the amount of heavy metal substances in the leachate into a de-heaving agent comprises:

[0018] When the heavy metal in the leachate does not contain lead, sulfide is added according to 1.1-1.2 times the amount of the heavy metal substance; when the heavy metal in the leachate contains lead, sulfide is added according to 1.1-1.2 times the amount of the heavy metal substance, and barium carbonate is added according to 1.1-1.2 times the amount of the lead substance;

[0019] The weight removal agent includes sulfide and barium carbonate.

[0020] Preferably, the preset time is greater than or equal to 2 hours, and the neutralizer is any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese carbonate, manganese hydroxide, and manganous oxide.

[0021] Preferably, the precipitant is one or more of ammonia water, potassium bicarbonate, ammonium bicarbonate and sodium bicarbonate.

[0022] Preferably, the step of subjecting the manganese sulfate solution to a precipitation reaction with a precipitant at a pH of 6-7.5, filtering and then slurrying and washing the precipitate with hot water comprises:

[0023] In the precipitation reaction process, the D50 particle size of the precipitate is controlled to be less than 10 microns, and the precipitate is washed to reduce the content of calcium and magnesium in the precipitate.

[0024] Preferably, the step of dissolving the washed precipitate in sulfuric acid, adding manganese fluoride at a fluorine-calcium molar ratio of 2.2-2.4:1 and filtering, adding a defluorinating agent at 3-10 times the mass of the fluorine solute to the filtered filtrate, filtering, evaporating and crystallizing to obtain manganese sulfate crystals comprises:

[0025] The washed precipitate is dissolved in sulfuric acid, and manganese fluoride is added at a molar ratio of fluoride to calcium of 2.2-2.4:1, wherein the reaction temperature after adding manganese fluoride is 70°C and the reaction time is 2h;

[0026] Filtering to obtain a filtrate;

[0027] Adding a defluorinating agent to the filtered filtrate at a rate of 3-10 times the mass of the fluorine solute, wherein the defluorinating agent is a polyaluminum sulfate defluorinating agent, the reaction temperature after adding the defluorinating agent is 60-80° C., and the reaction time is 2-4 hours;

[0028] The manganese sulfate crystals are obtained by filtration and evaporation.

[0029] A method for preparing manganese tetraoxide comprises the following steps:

[0030] After the manganese carbonate ore is pulped, sulfuric acid is added for leaching and an oxidant is added to obtain a leaching solution;

[0031] The leachate is added with a de-heaving agent according to 1.1-1.2 times the amount of the heavy metal substance, and filtered after a preset reaction time, and a neutralizing agent is added to the filtered filtrate to control the pH to 4.5-5.5, and then filtered to obtain a manganese sulfate solution;

[0032] The manganese sulfate solution and the precipitant are subjected to a precipitation reaction under the condition of pH 6-7.5, and the precipitate is washed by slurrying with hot water after filtering to obtain a washed precipitate;

[0033] The washed precipitate is dissolved in an inorganic acid, manganese fluoride is added in a fluorine-calcium molar ratio of 2.2-2.4:1, and then filtered, and a defluorinating agent is added to the filtered filtrate in an amount of 3-10 times the mass of the fluorine solute, and the manganese salt solution after impurity removal is obtained after filtering;

[0034] Put pure water in the reactor as the reaction base liquid and heat it to the reaction temperature;

[0035] Adding alkaline solution, oxidant, additive and impurity-removed manganese salt solution into the reaction kettle in a preset ratio;

[0036] The product slurry is taken out from the reactor, filtered, washed and dried to obtain the trimanganese tetraoxide.

[0037] Preferably, the step of placing pure water in a reaction kettle as a reaction base liquid and heating the temperature to a reaction temperature comprises:

[0038] Pure water is placed in a reaction kettle as a reaction base liquid, and an alkaline solution is added thereto to obtain a mixed liquid. The pH of the mixed liquid is maintained between 7 and 10, and the temperature is raised to the reaction temperature.

[0039] Preferably, the inorganic acid is one of sulfuric acid, nitric acid and hydrochloric acid.

[0040] Preferably, it includes:

[0041] The alkaline solution can be one or more of sodium hydroxide, potassium hydroxide, and ammonia water; the reaction temperature is 10-90°C, preferably 30-60°C.

[0042] Preferably, it includes:

[0043] The manganese salt may be one or more soluble divalent manganese salts;

[0044] The oxidant may be any one or more of air, oxygen, hydrogen peroxide, and ozone.

[0045] Preferably, the additive includes one or more of hydrazine, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, butyronitrile acetic acid, aminodiacetic acid, glycine, hexamethylenetetramine, oxalic acid, sodium oxalate, ammonium oxalate, and hexadecyltrimethylammonium bromide.

[0046] Compared with the prior art, the present invention has the following beneficial effects:

[0047] 1. The method for preparing manganese sulfate crystals from domestic manganese carbonate ore provided by the invention reduces the dependence on imported high-grade manganese ore. The invention first uses low-grade manganese carbonate ore to add sulfuric acid to leach valuable metals, and most of the Ca 2+ Remove with precipitation by filtration, and introduce air or other oxidants during the leaching process to make Fe 2+ Converted to Fe 3+ , so that it is completely precipitated during the neutralization process, and further, it avoids the addition of oxidants during the neutralization process to cause Mn 2+ Oxidation. Add a de-heaving agent to precipitate heavy metals, and then add a neutralizer to remove Fe 2+ , Fe 3+ With Al 3+The manganese sulfate solution is reacted with a precipitant to remove Ca and Mg along with the filtered filtrate. Taking ammonium bicarbonate as a precipitant, the precipitate obtained is manganese carbonate crystals. The solubility of manganese carbonate crystals is extremely low, while magnesium compounds have a large solubility under neutral conditions. Washing with hot water can remove more than 95% of the Mg 2+ Remove, thereby obtaining manganese carbonate solid containing very little Ca and Mg impurities. Compared with the traditional process that completely relies on fluoride to remove calcium and magnesium, the consumption of fluoride in this process is greatly reduced. It only needs to reverse dissolve the obtained manganese carbonate solid and add a small amount of fluoride for refining and impurity removal, which greatly improves the economy of the impurity removal process. Finally, a defluorinating agent is added to the filtrate, and then battery-grade manganese sulfate crystals are obtained after filtration, evaporation and crystallization. The product obtained by this invention has good impurity removal effect and low cost, and meets the first-class product standard in "HG-T-4823-2015 Manganese Sulfate for Batteries".

[0048] 2. The present invention provides a method for preparing a battery-grade manganese tetraoxide material, wherein the manganese tetraoxide material prepared by the method has good sphericity and high tap density. It is an important raw material for synthesizing manganese-based positive electrode materials and can improve the energy density and cycle performance per unit volume of positive electrode materials. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings required for use in the embodiments are briefly introduced below. It should be understood that the following drawings only show certain embodiments of the present invention and therefore should not be regarded as limiting the scope. For ordinary technicians in this field, other related drawings can be obtained based on these drawings without creative work.

[0050] Figure 1 The present invention is a schematic diagram of a process for preparing manganese sulfate crystals using manganese carbonate ore in an embodiment of the present invention;

[0051] Figure 2 This is a SEM schematic diagram of manganese tetraoxide prepared in an embodiment of the present invention;

[0052] Figure 3 This is a SEM schematic diagram of manganese tetraoxide prepared in an embodiment of the present invention;

[0053] Figure 4 Schematic diagram of the process for preparing manganese tetraoxide in an embodiment of the present invention. DETAILED DESCRIPTION

[0054] In order to better understand the above technical solution, exemplary embodiments of the present disclosure will be described in more detail below with reference to the accompanying drawings. Although exemplary embodiments of the present disclosure are shown in the accompanying drawings, it should be understood that the present disclosure can be implemented in various forms and should not be limited by the embodiments described herein. On the contrary, these embodiments are provided to enable a more thorough understanding of the present disclosure and to fully convey the scope of the present disclosure to those skilled in the art.

[0055] It should be understood that the specific embodiments described herein are only used to explain the present invention, and are not used to limit the present invention.

[0056] The composition of the manganese carbonate ore used in the embodiments of the present invention is shown in Table 1.

[0057] Table 1 Main components of manganese carbonate ore

[0058]

[0059] Example 1

[0060] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0061] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.45mL:1g, and leach at 70°C for 4h. During the leaching process, air aeration is used (air is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Air can be replaced by any one or more of oxygen, ozone, and hydrogen peroxide). After the reaction is completed, an initial manganese sulfate leachate is obtained;

[0062] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-to-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.45mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese ion concentration was 100.61g / L.

[0063] S2: adding solid ammonium sulfide in an amount of 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount of 1.2 times the amount of lead substances to the above manganese sulfate leachate, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation (ammonium sulfide can be replaced by any one or more of sodium sulfide, potassium sulfide or sodium hydrosulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0064] Add manganese carbonate to the manganese sulfate solution after heavy metal removal, adjust the pH to about 5, react at 70° C. for 2 hours, and obtain a neutralized manganese sulfate solution after solid-liquid separation (manganese carbonate can be replaced by any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0065] S3: The neutralized manganese sulfate solution and the ammonium bicarbonate solution are introduced into the reactor in a molar ratio of 1:2.1, and the pH is controlled to be 7 for precipitation reaction. The D50 particle size of the product particles is measured to be 6.9 μm. The slurry after the reaction is separated from the solid and liquid to obtain manganese carbonate solid (ammonium bicarbonate can be replaced by one of ammonia water, potassium bicarbonate, and sodium bicarbonate, and the precipitant can be in excess of 5-10% according to the reaction stoichiometric ratio);

[0066] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0067] S4: dissolving manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.2:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0068] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T-4823-2023 Manganese Sulfate for Batteries".

[0069] The impurity indicators measured in each impurity removal process of S1-S7 in Example 1 are shown in Tables 2-4.

[0070] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 4.

[0071] Table 2: Main components of S1 leachate

[0072] Mn Ca Mg Fe Al K Na Cu Zn Pb Si 100.61 0.54 15.68 26.34 0.44 0.12 0.06 0.0402 0.22 0.08 0.59 g / L g / L g / L g / L g / L g / L g / L g / L g / L g / L g / L

[0073] Table 3: Main components of manganese sulfate reverse solution

[0074]

[0075] Table 4: Main components of manganese sulfate crystals

[0076]

[0077] From Tables 1 to 4, it can be seen that the preparation method of manganese sulfate crystals of the present invention, by comparing the indicators measured in the leaching process of Table 2 with the indicators measured in each process of S2 to S4 of Table 3, it can be seen that the heavy metal removal step S2 can avoid excessive heavy metals such as Cu, Zn, Cr, Pb, Cd in manganese sulfate (the content of heavy metals such as Ni, Co, Cr, Pb, Cd, Cu, Zn detected in the table is the impurity content index required by the battery-grade manganese sulfate standard, and one or more of them must be contained in natural ores, and the method provided by the present invention can remove them). Regarding the removal of calcium and magnesium impurities, for the existing technology of removing calcium and magnesium by fluoride precipitation, due to the excessively high calcium and magnesium content of manganese carbonate ore, a large amount of fluoride needs to be added for treatment, and the price of fluoride is high, the treatment cost is high, and there is no economic benefit. Fluoride is relatively, and for the existing technology of removing calcium and magnesium impurities by carbon dioxide aeration washing manganese carbonate, because it is essentially chemical washing, it can only wash away the calcium and magnesium adsorbed on the surface of the crystal particles, while the calcium and magnesium coated inside the crystal cannot be removed. Therefore, the composition of the reverse solution after the manganese carbonate treated by carbon dioxide aeration washing does not meet the requirements of battery-grade manganese sulfate. Comparing Table 2, Table 3 and Table 4, it can be seen that by reverse-dissolving the manganese carbonate precipitate with sulfuric acid, adding a small amount of fluoride to the manganese sulfate solution can further remove calcium and magnesium in the manganese sulfate solution, so that the residual calcium and magnesium reach the standard of battery-grade manganese sulfate. As shown in Table 2, the removal rates of calcium and magnesium in the previous step have reached more than 95%, so in the step of adding fluoride, the amount of fluoride used is greatly reduced, reducing the production cost.

[0078] Example 2

[0079] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0080] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.45mL:1g, and leach at 70°C for 4h. During the leaching process, air aeration is used (air is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Air can be replaced by any one or more of oxygen, ozone, and hydrogen peroxide). After the reaction is completed, an initial manganese sulfate leachate is obtained;

[0081] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.45mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 100.35g / L.

[0082] S2: Add 30% NaSH solution according to 1.2 times the amount of heavy metal substances and add solid barium carbonate according to 1.2 times the amount of lead substances into the above manganese sulfate leachate, react for 2 hours, and obtain a manganese sulfate solution after heavy metal removal after solid-liquid separation (sodium hydrosulfide can be replaced by any one of sodium sulfide, potassium sulfide or ammonium sulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0083] Add 32% NaOH to the manganese sulfate solution after heavy metal removal, adjust the pH to about 5, react at 70° C. for 1 hour, and obtain a neutralized manganese sulfate solution after solid-liquid separation (manganese carbonate can be replaced by any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0084] S3: The neutralized manganese sulfate solution and the sodium bicarbonate solution are introduced into the reactor in parallel at a molar ratio of 1:2.1, and the pH is controlled to be 9 for precipitation reaction. The particle size D50 of the product particles is measured to be 12.4 μm. The slurry after the reaction is separated from the solid and liquid to obtain manganese carbonate solid (the sodium bicarbonate solution can be replaced by one of ammonia water, potassium bicarbonate, and ammonium bicarbonate, and the precipitant can be in excess of 5-10% according to the reaction stoichiometric ratio);

[0085] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0086] S4: dissolving manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.2:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0087] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T-4823-2023 Manganese Sulfate for Batteries".

[0088] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 5.

[0089] Table 5: Main components of manganese sulfate crystal products

[0090]

[0091] Example 3

[0092] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0093] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.45mL:1g, and leach at 70°C for 4h. Use oxygen aeration during the leaching process (oxygen is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Oxygen can be replaced by any one or more of air, ozone, and hydrogen peroxide). After the reaction is completed, the primary manganese sulfate leachate is obtained;

[0094] The above manganese sulfate leaching solution was used as the leaching base solution and mixed with the newly added manganese carbonate ore at a liquid-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.45mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 100.43g / L.

[0095] S2: adding solid sodium sulfide in an amount of 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount of 1.2 times the amount of lead substances to the above manganese sulfate leachate, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation (sodium sulfide can be replaced by any one of ammonium sulfide, potassium sulfide or sodium hydrosulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0096] Add Ca(OH)2 to the manganese sulfate solution after heavy metal removal, adjust the pH to about 5, react at 70°C for 1 hour, and obtain a neutralized manganese sulfate solution after solid-liquid separation (calcium hydroxide can be replaced by any one or more of calcium oxide, manganese carbonate, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0097] S3: The neutralized manganese sulfate solution and the sodium bicarbonate solution are introduced into the reactor in parallel at a molar ratio of 1:2.1, and the pH is controlled to be 9 for precipitation reaction. The slurry after the reaction is solid-liquid separated to obtain a manganese precipitate (the sodium bicarbonate solution can be replaced by one of ammonium bicarbonate, ammonia water, and potassium bicarbonate, and the precipitant can be in excess of 5-10% according to the reaction stoichiometric ratio);

[0098] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0099] S4; dissolving the manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.3:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0100] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T-4823-2023 Manganese Sulfate for Batteries".

[0101] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 6.

[0102] Table 6: Main product components of manganese sulfate crystals

[0103]

[0104] Example 4

[0105] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0106] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.5mL:1g, and leach at 70°C for 4h. During the leaching process, air aeration is used (air is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Air can be replaced by any one or more of oxygen, ozone, and hydrogen peroxide). After the reaction is completed, the primary manganese sulfate leachate is obtained;

[0107] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.5mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 100.39g / L.

[0108] S2: adding solid ammonium sulfide in an amount of 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount of 1.2 times the amount of lead substances to the above manganese sulfate leachate, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation (ammonium sulfide can be replaced by any one of sodium sulfide, potassium sulfide or sodium hydrosulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0109] Sodium carbonate is added to the manganese sulfate solution after heavy metal removal, the pH is adjusted to about 5, and the reaction is carried out at 70° C. for 2 hours. After solid-liquid separation, a neutralized manganese sulfate solution is obtained (sodium carbonate can be replaced by any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, manganese carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0110] S3: The neutralized manganese sulfate solution and ammonia water are introduced into a reactor in a molar ratio of 1:2.1, and the pH is controlled to be 9 for precipitation reaction. The particle size D50 of the product particles is measured to be 10.2 μm. The slurry after the reaction is separated from the solid and liquid to obtain manganese hydroxide solid (ammonia water can be replaced by potassium bicarbonate, sodium bicarbonate, and ammonium bicarbonate, and the precipitant can be in excess of 5-10% according to the reaction stoichiometric ratio);

[0111] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0112] S4: dissolving manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.3:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0113] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T4823-2023 Manganese Sulfate for Batteries".

[0114] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 7.

[0115] Table 7: Main components of manganese sulfate crystal products

[0116]

[0117] Example 5

[0118] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0119] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.5mL:1g, and leach at 70°C for 4h. Use oxygen aeration during the leaching process (oxygen is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Oxygen can be replaced by any one or more of air, ozone, and hydrogen peroxide). After the reaction is completed, the initial manganese sulfate leachate is obtained;

[0120] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.5mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 101.54g / L.

[0121] S2: adding solid ammonium sulfide in an amount of 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount of 1.2 times the amount of lead substances to the above manganese sulfate leachate, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation (ammonium sulfide can be replaced by any one of sodium sulfide, potassium sulfide or sodium hydrosulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0122] Add manganese carbonate to the manganese sulfate solution after heavy metal removal, adjust the pH to about 5, react at 70° C. for 2 hours, and obtain a neutralized manganese sulfate solution after solid-liquid separation (manganese carbonate can be replaced by any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0123] S3: The neutralized manganese sulfate solution and the ammonium bicarbonate solution are introduced into the reactor in parallel at a molar ratio of 1:2.1, and the pH is controlled to be 7 for precipitation reaction. The particle size D50 of the product particles is measured to be 9.8 μm. The slurry after the reaction is separated from the solid and liquid to obtain manganese carbonate solid (the ammonium bicarbonate solution can be replaced by one of ammonia water, potassium bicarbonate, and sodium bicarbonate, and the precipitant can be in excess of 5-10% according to the stoichiometric ratio of the reaction);

[0124] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0125] S4: dissolving manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.4:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0126] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T4823-2023 Manganese Sulfate for Batteries".

[0127] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 8.

[0128] Table 8: Main components of manganese sulfate crystal products

[0129]

[0130] Example 6

[0131] A method for preparing manganese sulfate using manganese carbonate ore comprises the following steps:

[0132] S1: Slurry the manganese carbonate ore at a liquid-solid ratio of 4:1, add concentrated sulfuric acid at an acid-ore ratio of 0.6mL:1g, and leach at 70°C for 4h. During the leaching process, air aeration is used (air is used to oxidize divalent iron to trivalent iron, so that Fe can be completely precipitated during the neutralization process. Air can be replaced by any one or more of oxygen, ozone, and hydrogen peroxide). After the reaction is completed, an initial manganese sulfate leachate is obtained;

[0133] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-to-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.6mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 102.16g / L.

[0134] S2: adding solid ammonium sulfide in an amount of 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount of 1.2 times the amount of lead substances to the above manganese sulfate leachate, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation (ammonium sulfide can be replaced by any one of sodium sulfide, potassium sulfide or sodium hydrosulfide, and solid barium carbonate needs to be added only when the leachate contains lead);

[0135] Add manganese carbonate to the manganese sulfate solution after heavy metal removal, adjust the pH to about 5, react at 70° C. for 2 hours, and obtain a neutralized manganese sulfate solution after solid-liquid separation (manganese carbonate can be replaced by any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese hydroxide, and manganous oxide, and the reaction time is greater than or equal to 2 hours).

[0136] S3: The neutralized manganese sulfate solution and ammonium bicarbonate solution are introduced into the reactor in a molar ratio of 1:2.1, and the pH is controlled to 7 for precipitation reaction. The particle size D50 of the product particles is measured to be 6.7 μm. After the reaction, the slurry is subjected to solid-liquid separation to obtain manganese carbonate solid (the ammonium bicarbonate solution can be replaced by one of ammonia water, potassium bicarbonate, and sodium bicarbonate, and Mn 2+ With CO3 2- The molar ratio is between 1:2.1-2.2);

[0137] The manganese carbonate solid was slurried and washed with hot water at 85°C for 30 minutes at a liquid-to-solid ratio of 3:1. After solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0138] S4: dissolving manganese carbonate solid at a manganese concentration of 160 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.4:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese sulfate solution after removing calcium and magnesium;

[0139] To the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added at a rate of 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T4823-2023 Manganese Sulfate for Batteries".

[0140] The manganese sulfate crystal product was analyzed by chemical titration and ICP-MS, and the results are shown in Table 9.

[0141] Table 9: Main components of manganese sulfate crystal products

[0142]

[0143] The following are the variables and their impurity removal results in different impurity removal processes in the embodiments:

[0144] Leaching process:

[0145] The differences in different parameters of various embodiments and their results are shown in Table 9. Except for the following parameters, the other parameters are the same.

[0146] Table 10 Differences in parameters and results of various embodiments during leaching

[0147] Example 1 2 3 4 5 6 Acid-ore ratio: ml acid / g ore 0.45：1 0.45：1 0.45：1 0.5：1 0.5：1 0.6：1 Manganese concentration of the first leaching solution after re-leaching g / L 100.61 100.35 100.43 100.39 101.54 102.16

[0148] It can be seen from Table 10 that as the acid-ore ratio increases, the manganese concentration of the primary leaching solution after re-leaching does not increase significantly, and the acid-ore ratio can be between 0.45 and 0.6, which has little effect on the leached manganese concentration.

[0149] Heavy metal removal process:

[0150] The differences in parameters of various embodiments and their results are shown in Table 8. Except for the following parameters, the other parameters are the same.

[0151] Table 11 Types of de-heavy agents and heavy metal contents of products in various examples

[0152]

[0153] It can be seen from Table 11 that the selection of ammonium sulfide, 30% NaSH and sodium sulfide as the deweighting agent does not affect the effect of removing Cu and Zn impurities.

[0154] Neutralization and impurity removal process:

[0155] The differences in different parameters of each embodiment and their results are shown in Table 12. Except for the following parameters, the other parameters are the same.

[0156] Table 12 Differences in parameters of various embodiments of the neutralization and impurity removal process and iron and aluminum content of the products

[0157] Example 1 2 3 4 5 6 Neutralizer Manganese carbonate 32% NaOH Ca(OH)2 Sodium carbonate Manganese carbonate Manganese carbonate Type of oxidant during leaching Air Air oxygen Air oxygen Air Reaction time 2 1 1 2 2 2 Fe(ppm) 1 2 2 1 0 1 Al(ppm) 0 1 0 1 0 0

[0158] It can be seen from Table 12 that different leaching oxidants, neutralizers and reaction times were selected in Examples 1-6. It can be seen that they have little effect on the impurity removal effect of Fe and Al. Manganese carbonate, 32% NaOH, calcium carbonate, and sodium carbonate can all be used as neutralizers, air and oxygen can both be used as oxidants, and the reaction time can be 1-2h.

[0159] Manganese precipitation process and anti-dissolution process:

[0160] The differences in different parameters of each embodiment and their results are shown in Table 13. Except for the following parameters, the other parameters are the same.

[0161] Table 13 Differences in parameters of various embodiments during manganese precipitation and their anti-dissolution results

[0162]

[0163] As shown in Table 13, by comparing Example 1 with Examples 5 and 6, it can be seen that the D50 particle size of the product will affect the impurity removal effect of Mg. The D50 particle size of the product can be controlled by controlling the product discharge speed. The smaller the particle size, the better the Mg removal effect. In fact, the product particle size of about 10 μm has little effect on the impurity removal effect. Examples 1-6 all meet the product standard of battery-grade manganese sulfate.

[0164] Comparative Example 1

[0165] The difference between Comparative Example 1 and Example 1 is that the Example uses ammonium sulfide and barium carbonate to remove heavy metals, while the comparative example does not use a specific method to remove heavy metals, and other impurity removal reagents and impurity removal conditions are the same. The heavy metal content of the manganese sulfate crystals prepared in this comparative example is shown in Table 14:

[0166] Table 14 Heavy metal content of manganese sulfate crystals prepared in Comparative Example 1

[0167] element Cr Pb Cd Cu Zn content(%) Not detected 0.09 Not detected 0.02 0.08

[0168] As shown in Table 14, Example 1 used ammonium sulfide and barium carbonate to remove heavy metals, while the comparative example did not use a specific method to remove heavy metals. It can be seen that the content of heavy metals in the product of comparative example 1 is too high and does not meet the standard of "HG / T 4823-2015 Manganese Sulfate for Batteries".

[0169] Comparative Example 2

[0170] The difference between Comparative Example 2 and Example 1 is that Comparative Example 2 adopts the method of adding carbon dioxide aeration during the manganese carbonate pulp washing process to make the pH value during the pulp washing process less than 6, and directly dissolving with sulfuric acid after washing, filtering out impurities and then evaporating and crystallizing to remove Ca and Mg impurities. The calcium and magnesium contents of the obtained manganese sulfate crystals are as shown in Table 15:

[0171] Table 15 Heavy metal content of manganese sulfate crystals prepared in Comparative Example 2

[0172] element Ca Mg content(%) 0.02 0.09

[0173] As shown in Table 15, during the washing process of manganese carbonate pulp, carbon dioxide was added for aeration to make the pH value less than 6 during the washing process. After washing, sulfuric acid was used to dissolve the manganese sulfate crystals, and then the manganese sulfate crystals were obtained by evaporation and crystallization. The impurity contents of Ca and Mg were too high and did not meet the standard of "HG / T 4823-2015 Manganese Sulfate for Batteries".

[0174] Comparative Example 3

[0175] The difference between Comparative Example 3 and Example 1 is that Comparative Example 3 uses Ca(OH)2 as a precipitant and the precipitation pH is 12, and other impurity removal agents and impurity removal conditions are the same.

[0176] Comparative Example 4

[0177] The difference between Comparative Example 4 and Example 1 is that Comparative Example 4 uses 32% NaOH as a precipitant and the precipitation pH is 12, and other impurity removal reagents and impurity removal conditions are the same.

[0178] Comparative Example 5

[0179] The difference between Comparative Example 5 and Example 1 is that Comparative Example 5 uses Na2CO3 as a precipitant and the precipitation pH is 11, and other impurity removal reagents and impurity removal conditions are the same.

[0180] Table 16 Comparison of indicators of comparative examples 3, 4 and 5 in the anti-dissolution experiment

[0181]

[0182] As shown in Table 16, when using a calcium precipitant, only sulfuric acid can be used as the counter solution, otherwise the calcium in the precipitate will be completely dissolved, which will cause the calcium ion concentration of the counter solution to be too high, and the subsequent use of fluoride to remove calcium and magnesium is not economical.

[0183] Since comparative examples 3, 4, and 5 use substances with too strong alkalinity as precipitation agents, the pH value is too high during the precipitation reaction, and Mg is co-precipitated in the form of magnesium hydroxide, and the manganese crystals will be coated with the magnesium hydroxide on the surface in the crystal during the growth process, resulting in the inability to remove magnesium in the washing process, which is not ideal. In particular, when calcium agents such as calcium hydroxide and calcium oxide are used as precipitation agents, a large amount of calcium sulfate crystals are also produced, resulting in an increase in precipitates and an increase in the amount of Mg entrained. In view of the Mg concentration in the reverse solution of comparative examples 1, 2, and 3, it is not ideal to use fluoride to treat, whether it is removal effect or economic benefit. Therefore, strong alkaline substances are not suitable as precipitation agents in the present invention, and precipitation agents are preferably acid carbonates such as ammonium bicarbonate and sodium bicarbonate.

[0184] The present application also provides a method for preparing manganese tetraoxide, comprising the following steps:

[0185] S10, slurrying manganese carbonate, adding sulfuric acid for leaching and adding an oxidant to obtain a leachate;

[0186] S20, adding a de-weighting agent according to 1.1-1.2 times the amount of heavy metal substances in the leachate, filtering after a preset reaction time, adding a neutralizing agent to the filtered filtrate, controlling the pH to 4.5-5.5, and then filtering to obtain a manganese sulfate solution;

[0187] S30, subjecting the manganese sulfate solution and the precipitant to a precipitation reaction at a pH of 6-7.5, filtering and washing the precipitate with hot water slurry to obtain a washed precipitate;

[0188] S40, dissolving the washed precipitate in an inorganic acid, adding manganese fluoride at a fluorine-calcium molar ratio of 2.2:1, and filtering, adding a defluorinating agent at 3-10 times the mass of the fluorine solute to the filtered filtrate, and filtering to obtain a manganese salt solution after impurities are removed;

[0189] S50, placing pure water in the reaction kettle as a reaction bottom liquid, and heating the reaction kettle to a reaction temperature;

[0190] S60, adding the alkaline solution, the oxidant, the additive and the manganese salt solution after impurities are removed into the reaction kettle in a preset ratio;

[0191] S70, taking out the product slurry from the reactor, filtering, washing and drying to obtain the trimanganese tetraoxide.

[0192] Specifically, the inorganic acid in this embodiment can be strong acids such as sulfuric acid, hydrochloric acid, and nitric acid.

[0193] As an embodiment (hereinafter referred to as Embodiment 7), Embodiment 7 in the present application provides a method for preparing manganese tetraoxide using manganese sulfate, comprising the following steps:

[0194] S10: slurrying the manganese carbonate ore at a liquid-solid ratio of 4:1, adding concentrated sulfuric acid at an acid-ore ratio of 0.45 mL:1 g, leaching at 70° C. for 4 h, and using air aeration during the leaching process; after the reaction is completed, an initial manganese sulfate leaching solution is obtained;

[0195] The above manganese sulfate initial leaching solution was used as the leaching bottom solution, and was mixed with the newly added manganese carbonate ore at a liquid-solid ratio of 4:1 to form a slurry, and concentrated sulfuric acid was added at an acid-ore ratio of 0.45mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 100.45g / L.

[0196] S20: adding solid ammonium sulfide according to 1.2 times the amount of heavy metal substances and solid barium carbonate according to 1.2 times the amount of lead substances into the above manganese sulfate leaching solution (barium carbonate is added according to actual conditions, and barium carbonate may not be added if lead is not detected in the early stage), reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation;

[0197] Manganese carbonate was added to the manganese sulfate solution after heavy metal removal, the pH was adjusted to about 5, and the reaction was carried out at 70° C. for 1 hour. After solid-liquid separation, a neutralized manganese sulfate solution was obtained.

[0198] S30: introducing the neutralized manganese sulfate solution and the ammonium bicarbonate solution into a reaction kettle in a molar ratio of 1:2.1, controlling the pH value to be within the range of 6-7.5 for precipitation reaction, and measuring the particle size D50 of the product particles to be 6.9 μm. After the reaction, the slurry is subjected to solid-liquid separation to obtain manganese carbonate solid;

[0199] The manganese carbonate solid was slurried and washed with hot water at 75-90° C. for 30 minutes at a liquid-to-solid ratio of 3:1, and after solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0200] S40: dissolving manganese carbonate solid with sulfuric acid at a manganese concentration of 120 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.2:1, reacting at 70° C., and after 2 hours, solid-liquid separation to obtain a manganese sulfate solution after calcium and magnesium are removed;

[0201] Into the fluorine-containing manganese sulfate solution, polyaluminum sulfate defluorinating agent was added in an amount 5 times the mass of fluorine solute. After reacting at 70°C for 3 hours, manganese sulfate crystals were obtained after solid-liquid separation and evaporation crystallization. After testing, the manganese sulfate crystals met the first-class product standards in "HG / T4823-2015 Manganese Sulfate for Batteries".

[0202] (The parameters of the above steps S1-S4 are the same as those in Example 1-6. The main components of the manganese carbonate ore used are shown in Table 1. The parameter range and reagent selection range are also the same. The raw material of manganese tetraoxide is battery-grade manganese sulfate solution)

[0203] S50: Take the above-mentioned battery-grade manganese sulfate crystals and hydrazine monohydrate, add pure water to prepare a solution with a manganese mass concentration of 120 g / L and a hydrazine concentration of 1.5 g / L (the battery-grade manganese sulfate can be replaced by any one or more soluble divalent manganese salts, and the hydrazine monohydrate in this step can be replaced by one or more of hydrazine, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, butyronitrile acetic acid, aminodiacetic acid, glycine, hexamethylenetetramine, oxalic acid, sodium oxalate, ammonium oxalate, and hexadecyltrimethylammonium bromide).

[0204] S60: Manganese sulfate solution at a flow rate of 300 L / h, 32% sodium hydroxide at a mass fraction of 125 L / h, and air at a flow rate of 2.7 m 3 / min flow into the reactor in parallel, the pH needs to be controlled during the reaction to facilitate the reaction of various substances, in this embodiment, the reaction pH is maintained at 9 by fine-tuning the sodium hydroxide feed flow rate, the reaction temperature is maintained at 60°C, and the product is continuously discharged from the overflow port after a period of reaction, and the reaction is stopped after 72h of reaction (in other embodiments, an alkaline solution is introduced to maintain the pH range between 7-10, and the alkaline solution introduced can be selected from one or more of sodium hydroxide, potassium hydroxide, and ammonia water according to the situation, and the reaction temperature is controlled at 10-90°C, preferably 30-60°C).

[0205] S70: Collect the slurry from the overflow port for 24 hours, filter it, wash it with pure water until it is neutral, and then dry it in an oven at 120℃ to obtain the manganese tetraoxide product. After testing, the manganese content of the sample is 71.32%, D50 is 9.85μm, and the tap density is 2.58g / cm 3 , with a specific surface area of ​​0.54m 2 / g, and its impurity content meets the standards of battery-grade materials. Its SEM image is shown in Figure 2 shown.

[0206] As an embodiment (hereinafter referred to as Embodiment 8), when the inorganic acid is hydrochloric acid, Embodiment 8 in the present application provides a method for preparing manganese tetraoxide using manganese chloride, comprising the following steps:

[0207] S10: slurrying the manganese carbonate ore at a liquid-solid ratio of 4:1, adding concentrated sulfuric acid at an acid-ore ratio of 0.45 mL: 1 g, leaching at 70° C. for 4 h, and using air aeration during the leaching process; after the reaction is completed, a primary manganese sulfate leaching solution is obtained;

[0208] The above manganese sulfate leaching solution was used as the leaching base solution and mixed with the newly added manganese carbonate ore at a liquid-to-solid ratio of 5:1 to form a slurry, and sulfuric acid was added at an acid-ore ratio of 0.45mL:1g. Leaching was carried out again under the above conditions. After the reaction was completed, a manganese sulfate leaching solution was obtained, and its manganese concentration was 80.96g / L.

[0209] S20: adding solid ammonium sulfide in an amount 1.2 times the amount of heavy metal substances and solid barium carbonate in an amount 1.2 times the amount of lead substances into the above manganese sulfate leaching solution, reacting for 2 hours, and obtaining a manganese sulfate solution after heavy metal removal after solid-liquid separation;

[0210] Manganese carbonate was added to the manganese sulfate solution after heavy metal removal, the pH was adjusted to about 5, and the reaction was carried out at 70° C. for 1 hour. After solid-liquid separation, a neutralized manganese sulfate solution was obtained.

[0211] S30: introducing the neutralized manganese sulfate solution and the ammonium bicarbonate solution into a reaction kettle in a molar ratio of 1:2.1, controlling the pH value to be within the range of 6-7.5 for precipitation reaction, and measuring the particle size D50 of the product particles to be 9.8 μm. After the reaction, the slurry is subjected to solid-liquid separation to obtain manganese carbonate solid;

[0212] The manganese carbonate solid was slurried and washed with hot water at 75-90° C. for 30 minutes at a liquid-to-solid ratio of 3:1, and after solid-liquid separation, it was washed again under the above conditions to obtain pure manganese carbonate solid.

[0213] S40: dissolving the manganese carbonate solid with hydrochloric acid at a manganese concentration of 120 g / L, and adding manganese fluoride at a fluorine: (calcium + magnesium) molar ratio of 2.2:1, reacting at 70° C. for 2 hours, and separating the solid and liquid to obtain a manganese chloride solution after removing calcium and magnesium;

[0214] Into the fluorine-containing manganese chloride solution, a polyaluminium sulfate defluorinating agent is added according to 5 times the mass of the fluorine solute, and after reacting at 70°C for 3 hours, a purified manganese chloride solution is obtained.

[0215] (The parameters of the above steps S1-S4 are the same as those in Example 1-6. The main components of the manganese carbonate ore used are shown in Table 1. The parameter range and the reagent selection range are also the same. The raw material of manganese tetraoxide is a manganese chloride solution that meets the requirements for producing battery-grade materials)

[0216] S50: taking the purified manganese chloride solution and disodium ethylenediaminetetraacetate, adding pure water to prepare a manganese chloride solution with a manganese mass concentration of 120 g / L and a disodium ethylenediaminetetraacetate concentration of 1 g / L (battery-grade manganese sulfate can be replaced by any one or more soluble divalent manganese salts, and the hydrazine monohydrate in this step can be replaced by one or more of hydrazine, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, butyronitrile acetic acid, aminodiacetic acid, glycine, hexamethylenetetramine, oxalic acid, sodium oxalate, ammonium oxalate, and hexadecyltrimethylammonium bromide);

[0217] S60: the purified manganese chloride solution is fed into the reactor at a flow rate of 250 L / h, 10.6 mol / L potassium hydroxide is fed at a flow rate of 105 L / h, and 30% hydrogen peroxide is fed into the reactor at a flow rate of 28 L / h in parallel. During the reaction, the reaction pH is maintained at 8.8 by fine-tuning the potassium hydroxide feed flow rate, and the reaction temperature is maintained at 50°C. After a period of reaction, the product is continuously discharged from the overflow port. The reaction is stopped after 72 hours of reaction (the alkaline solution is introduced to maintain the pH range between 7-10, which is the same as the purpose in step S5, and the alkaline solution introduced can be selected from one or more of sodium hydroxide, potassium hydroxide, and ammonia water according to the situation, and the reaction temperature is controlled at 10-90°C, preferably 30-60°C).

[0218] S70: Collect the slurry from the overflow port for 24 hours, filter it, wash it with pure water until it is neutral, and then dry it in an oven at 120℃ to obtain the manganese tetraoxide product. After testing, the manganese content of the sample is 71.28%, D50 is 14.45μm, and the tap density is 2.77g / cm 3 , with a specific surface area of ​​1.10m 2 / g, and its impurity content meets the standards of battery-grade materials. Its SEM image is shown in Figure 3 shown.

[0219] The difference between the above-mentioned Example 7 and Example 8 is mainly that when the manganese carbonate is reversely dissolved in S40, one uses sulfuric acid and the other uses hydrochloric acid. In other embodiments, other strong inorganic acids can also be used. However, no matter which strong acid is used as the inorganic acid, in the process of preparing the reaction base liquid in step S50, the pH of the reaction base liquid can be further adjusted to 7-10 using an alkaline solution. Specifically, before S60, the alkaline solution is mixed with pure water, and a reaction kettle with a volume of 5000L with a stirring device and an overflow port is added as the reaction base liquid, and the pH is controlled between 7-10, and the reaction temperature is controlled at 10-90°C, preferably 30-60°C. The advantage of adjusting the pH of the reaction base liquid first over not adjusting the pH of the reaction base liquid in Examples 7 and 8 is that the pH of the mixed solution is adjusted between 7 and 10 in advance, creating an alkaline environment for the subsequent reaction in advance, which is more conducive to the occurrence of the subsequent reaction. However, it should be noted that not adjusting the pH of the reaction base liquid in advance has little effect on the final result of the product. Another difference is that in Example 7, manganese sulfate crystals are prepared before preparing manganese tetraoxide, while in Example 8, evaporation, crystallization and other steps are directly skipped, and the purified manganese salt solution is directly used to prepare manganese tetraoxide. The only difference is that the state of the manganese salt is different, which has no effect on the preparation of manganese tetraoxide and the product indicators. The purpose is to illustrate that the manganese salt solution prepared by the process of the present invention meets the raw material standard required for the production of battery-grade materials, and evaporation and crystallization are not necessary processes.

[0220] The above are only preferred embodiments of the present invention, and are not intended to limit the patent scope of the present invention. Any equivalent structure or equivalent process transformation made using the contents of the present invention specification and drawings, or directly or indirectly applied in other related technical fields, are also included in the patent protection scope of the present invention.

Claims

1. A method for preparing manganese sulfate crystals using manganese carbonate ore, characterized in that: The following steps are involved: After the manganese carbonate ore is pulped, sulfuric acid is added for leaching and an oxidant is added to obtain a leaching solution; The leachate is added with a de-heaving agent according to 1.1-1.2 times the amount of the heavy metal substance, and filtered after a preset reaction time, and a neutralizing agent is added to the filtered filtrate to control the pH to 4.5-5.5, and then filtered to obtain a manganese sulfate solution; The manganese sulfate solution and the precipitant are subjected to a precipitation reaction under the condition of pH 6-7.5, and the precipitate is washed by slurrying with hot water after filtering to obtain a washed precipitate; The washed precipitate is dissolved in sulfuric acid, manganese fluoride is added in a fluorine-calcium molar ratio of 2.2-2.4:1, and then filtered, and a defluorinating agent is added to the filtered filtrate in an amount of 3-10 times the mass of the fluorine solute, and then filtered and evaporated and crystallized to obtain the manganese sulfate crystals.

2. The method according to claim 1, characterized in that The step of slurrying the manganese carbonate ore, adding sulfuric acid for leaching and adding an oxidant to obtain a leachate comprises: The manganese carbonate ore is pulped and then sulfuric acid is added for leaching to obtain an initial leaching solution; Manganese carbonate ore is added to the initial leaching solution to prepare ore pulp, and then sulfuric acid is added to leach again to obtain the leaching solution, wherein the manganese concentration of the leaching solution is in the range of 80-140 g / L.

3. The method according to claim 1, characterized in that The step of adding 1.1-1.2 times the amount of heavy metal substances into the leachate to remove the heavy metals comprises: When the heavy metal in the leachate does not contain lead, sulfide is added according to 1.1-1.2 times the amount of the heavy metal substance; when the heavy metal in the leachate contains lead, sulfide is added according to 1.1-1.2 times the amount of the heavy metal substance, and barium carbonate is added according to 1.1-1.2 times the amount of the lead substance; The weight removal agent includes sulfide and barium carbonate.

4. The method according to claim 1, characterized in that The preset time is greater than or equal to 2 hours, and the neutralizer is any one or more of calcium oxide, calcium hydroxide, calcium carbonate, sodium hydroxide, potassium hydroxide, ammonia water, potassium carbonate, sodium carbonate, potassium bicarbonate, ammonium bicarbonate, sodium bicarbonate, manganese carbonate, manganese hydroxide, and manganous oxide.

5. The method according to claim 1, characterized in that The precipitant is one or more of ammonia water, potassium bicarbonate, ammonium bicarbonate and sodium bicarbonate.

6. The method according to claim 1, characterized in that The step of subjecting the manganese sulfate solution and the precipitant to a precipitation reaction at a pH of 6-7.5, filtering and then slurrying and washing the precipitate with hot water comprises: In the precipitation reaction process, the D50 particle size of the precipitate is controlled to be less than 10 microns, and the precipitate is washed to reduce the content of calcium and magnesium in the precipitate.

7. The method according to claim 1, characterized in that The steps of dissolving the washed precipitate in sulfuric acid, adding manganese fluoride at a fluorine-calcium molar ratio of 2.2-2.4:1, filtering, adding a defluorinating agent at 3-10 times the mass of the fluorine solute into the filtered filtrate, filtering, evaporating and crystallizing to obtain manganese sulfate crystals include: The washed precipitate is dissolved in sulfuric acid, and manganese fluoride is added at a molar ratio of fluoride to calcium of 2.2-2.4:1, wherein the reaction temperature after adding manganese fluoride is 70°C and the reaction time is 2h; Filtering to obtain a filtrate; Adding a defluorinating agent to the filtered filtrate at a rate of 3-10 times the mass of the fluorine solute, wherein the defluorinating agent is a polyaluminum sulfate defluorinating agent, the reaction temperature after adding the defluorinating agent is 60-80° C., and the reaction time is 2-4 hours; The manganese sulfate crystals are obtained by filtration and evaporation.

8. A method for preparing trimanganese tetraoxide, characterized in that: The following steps are involved: After the manganese carbonate ore is pulped, sulfuric acid is added for leaching and an oxidant is added to obtain a leaching solution; The leachate is added with a de-heaving agent according to 1.1-1.2 times the amount of the heavy metal substance, and filtered after a preset reaction time, and a neutralizing agent is added to the filtered filtrate to control the pH to 4.5-5.5, and then filtered to obtain a manganese sulfate solution; The manganese sulfate solution and the precipitant are subjected to a precipitation reaction under the condition of pH 6-7.5, and the precipitate is washed by slurrying with hot water after filtering to obtain a washed precipitate; The washed precipitate is dissolved in an inorganic acid, manganese fluoride is added in a fluorine-calcium molar ratio of 2.2-2.4:1, and then filtered, and a defluorinating agent is added to the filtered filtrate in an amount of 3-10 times the mass of the fluorine solute, and the manganese salt solution after impurity removal is obtained after filtering; Put pure water in the reactor as the reaction base liquid and heat it to the reaction temperature; Adding alkaline solution, oxidant, additive and impurity-removed manganese salt solution into the reaction kettle in a preset ratio; The product slurry is taken out from the reactor, filtered, washed and dried to obtain the trimanganese tetraoxide.

9. The preparation method according to claim 8, characterized in that: The step of placing pure water in a reaction kettle as a reaction base liquid and heating the temperature to a reaction temperature comprises: Pure water is placed in a reaction kettle as a reaction base liquid, and an alkaline solution is added thereto to obtain a mixed liquid. The pH of the mixed liquid is maintained between 7 and 10, and the temperature is raised to the reaction temperature.

10. The preparation method according to claim 8, characterized in that: include: The alkaline solution can be one or more of sodium hydroxide, potassium hydroxide, and ammonia water; the reaction temperature is 10-90°C, preferably 30-60°C.

11. The preparation method according to claim 8, characterized in that: include: The manganese salt may be one or more soluble divalent manganese salts; The oxidant may be any one or more of air, oxygen, hydrogen peroxide, and ozone.

12. The preparation method according to claim 8, characterized in that: The additive includes one or more of hydrazine, ethylenediaminetetraacetic acid, disodium ethylenediaminetetraacetate, butyronitrile acetic acid, aminodiacetic acid, glycine, hexamethylenetetramine, oxalic acid, sodium oxalate, ammonium oxalate, and hexadecyltrimethylammonium bromide.

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