A process for the production of battery-chemical manganese dioxide from industrial manganese carbonate

Abstract

The application relates to the technical field of battery chemical manganese dioxide preparation, and particularly discloses a method for producing battery chemical manganese dioxide from industrial manganese carbonate. The method comprises the following steps: ① impurity removal: removing metal impurities in the industrial manganese carbonate to obtain high-purity manganese carbonate; ② pyrolysis; ③ soaking and pickling; and ④ cleaning; wherein the metal impurities in the industrial manganese carbonate are removed by using a modified adsorbent in the step ①; the modified adsorbent is obtained by loading a precipitant on a water-absorbing porous adsorption resin, and the precipitant comprises manganese sulfide and manganese fluoride. The method has the advantage of low metal impurity content.

Description

Technical Field

[0001] This application relates to the technical field of battery chemical manganese dioxide preparation, and more specifically, it relates to a method for producing battery chemical manganese dioxide using industrial manganese carbonate. Background Technology

[0002] Electrolytic manganese dioxide (EMD) is a type of manganese dioxide with the chemical formula MnO2. It has numerous applications in daily life. Due to its excellent oxidizing properties, strong ion exchange and adsorption capabilities, oxidation / reduction and catalytic abilities, EMD is widely used in the manufacture of supercapacitors, electrocatalysis, and water purification. Its most important application is as a key raw material in manganese-based alkaline manganese batteries, ternary nickel-cobalt-manganese lithium oxide materials, lithium iron manganese phosphate, and lithium manganese oxide batteries. It is also popular in lithium, sodium, and magnesium-ion rechargeable batteries. Compared to natural manganese dioxide, EMD has advantages such as high chemical purity, good crystal structure, reasonable solid-phase surface properties, and good cathode forming characteristics, making it a major raw material for high-performance chemical batteries.

[0003] The preparation of manganese dioxide for batteries generally includes the following steps: leaching manganese from the raw materials, impurity removal, electrolysis, and post-treatment. Raw materials include minerals such as rhodochrosite, manganese carbonate ore, manganese oxide ore, manganese sulfate ore, pyrolusite, and diaspore ore; and industrial waste such as manganese sulfate waste liquid. Impurity removal primarily targets metallic impurities such as copper, iron, magnesium, cobalt, nickel, and lead. Impurity removal is a crucial operation, typically achieved through precipitation and adsorption. Precipitation involves adding a precipitant (calcium hydroxide, barium carbonate, calcium carbonate, etc.) to precipitate some metallic impurities, which are then removed by filtration. Subsequently, impurities are removed by adsorption with adsorbents (activated carbon, flocculants, etc.), cation exchange, and microfiltration or ultrafiltration.

[0004] As the battery industry places increasingly higher demands on battery performance, the purity requirements for manganese dioxide, the primary electrode material, are also becoming more stringent. However, the manganese dioxide obtained using the methods described above still suffers from high levels of metallic impurities. Summary of the Invention

[0005] To further reduce the impurities in battery manganese dioxide, this application provides a method for producing battery chemical manganese dioxide using industrial manganese carbonate.

[0006] This application provides a method for producing battery chemical manganese dioxide from industrial manganese carbonate, which includes the following steps:

[0007] ① Impurity removal: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate;

[0008] ② Pyrolysis: The high-purity manganese carbonate is placed in an environment of water vapor and air and heated to decompose it, yielding crude manganese dioxide;

[0009] ③ Immersion and pickling: The manganese dioxide is placed in a sulfuric acid solution and heated for immersion treatment to obtain pickled manganese dioxide;

[0010] ④ Cleaning: The acid-washed manganese dioxide is washed with water until neutral, and then dried to obtain battery chemical manganese dioxide;

[0011] In ①, a modified adsorbent is used to remove metallic impurities from industrial manganese carbonate; the modified adsorbent is obtained by loading a precipitant onto a water-absorbing porous adsorption resin, and the precipitant includes manganese sulfide and manganese fluoride.

[0012] By adopting the above technical solution, this application prepares battery chemical manganese dioxide from industrial manganese carbonate. First, compared with the original ore, industrial manganese carbonate has a higher manganese content and fewer metal impurities. After further removing impurities from the industrial manganese carbonate, high-purity manganese carbonate is obtained. Subsequently, the high-purity manganese carbonate is pyrolyzed in a humid, air-based environment to decompose and obtain manganese oxide (MnO2). Then, the manganese oxide is treated with sulfuric acid solution to further remove metal impurities, such as barium ions. Finally, it is washed with water until neutral and then dried to obtain battery chemical manganese dioxide with significantly reduced metal impurity content.

[0013] In this scheme, when removing impurities from industrial manganese carbonate, a modified adsorbent is used to further remove metallic impurities. The modified adsorbent is a water-absorbing and swelling porous resin loaded with a precipitant. As the modified adsorbent absorbs water and swells, its pores open. The manganese sulfide precipitant loaded on it reacts with impurities such as iron and aluminum ions to form precipitates, which fill and block the pores of the modified adsorbent. Simultaneously, impurities such as calcium and magnesium ions react with manganese fluoride to form precipitates, further filling and blocking the pores of the modified adsorbent. Furthermore, other metallic impurities originally present in industrial manganese carbonate are further adsorbed and fixed on the modified adsorbent, ultimately achieving the goal of significantly removing metallic impurities from the crude manganese sulfate solution.

[0014] Optionally, in step ②, the temperature for heating and decomposition is 300-400℃, and the heating and decomposition time is 30-120 min.

[0015] By adopting the above technical solution and combining the pyrolysis environment of water vapor and air, manganese oxide can be obtained at a relatively low pyrolysis temperature.

[0016] Optionally, the heating and decomposition operation in step ② is carried out in a fluidized bed furnace.

[0017] Optionally, in step ②, the water vapor content is 10-80% of that in air.

[0018] Optionally, in step ③, the heating and soaking time is 5-8 hours, and the heating temperature is 50-90℃.

[0019] Optionally, the method for removing impurities in ① includes the following steps:

[0020] S1. After crushing industrial manganese carbonate, add sulfuric acid solution to obtain crude manganese sulfate solution;

[0021] S2. The crude manganese sulfate solution and the modified adsorbent are mixed and filtered to obtain a refined manganese sulfate solution. The amount of the modified adsorbent added is 8-15 wt% of the industrial manganese carbonate.

[0022] S3. Mix the refined manganese sulfate solution and ammonium bicarbonate solution, filter, and obtain high-purity manganese carbonate.

[0023] By employing the above technical solution, industrial manganese carbonate is first leached with sulfuric acid to dissolve it, yielding manganese sulfate. During this process, iron ions, calcium ions, magnesium ions, and heavy metal ions (barium ions, cobalt ions, nickel ions, etc.) also dissolve along with the manganese ions. When the metals exist in ionic form, they can be removed using adsorption. Finally, the manganese sulfate is precipitated with ammonium bicarbonate to obtain high-purity manganese carbonate.

[0024] Optionally, the ammonium bicarbonate content in the ammonium bicarbonate solution is 10-14 wt%.

[0025] Optionally, the preparation method of the modified adsorbent includes the following steps:

[0026] I. Dissolve sodium carboxymethyl cellulose powder in an alkaline solution, cool to room temperature, and then add acrylic acid, N,N-methylenebisacrylamide, surfactant, manganese fluoride, and sodium carbonate. After uniform dispersion, an initial dispersion is obtained.

[0027] II. Add ammonium persulfate and sodium bisulfite to the initial dispersion, heat and stir, and let stand to obtain the initial product; III. Take out the initial product, crush and wash it, soak it in hydrochloric acid and wash it with water, and finally soak it in manganese sulfide dispersion, take it out, wash it with water and dry it to obtain the final product.

[0028] By employing the above-mentioned technical solution, sodium carboxymethyl cellulose, acrylic acid, and N,N-methylenebisacrylamide are used as raw materials, and ammonium persulfate is used as a catalyst under heating conditions to graft copolymerize sodium carboxymethyl cellulose and acrylic acid to obtain a superabsorbent resin. The reaction of sodium carbonate and sodium bisulfite generates gas, giving the modified adsorbent a porous structure. In this process, manganese fluoride is mixed with the polymerization raw materials and is therefore encapsulated within the resin to minimize secondary fluoride contamination from entering the crude manganese sulfate solution. The final product is then immersed in a manganese sulfide dispersion, allowing manganese sulfide to penetrate the pores of the superabsorbent resin, increasing the manganese sulfide loading rate and enhancing the metal ion removal effect of the modified adsorbent. Furthermore, since this superabsorbent resin is prepared from sodium carboxymethyl cellulose, acrylic acid, and N,N-methylenebisacrylamide, it possesses a high concentration of anions to facilitate the adsorption of metal cations.

[0029] Optionally, the weight ratio of acrylic acid to manganese fluoride is 1:(0.01-0.03); the weight ratio of acrylic acid to manganese sulfide is 1:(0.04-0.08).

[0030] Optionally, the manganese sulfide dispersion contains 20-40 wt% manganese sulfide.

[0031] By adopting the above technical solution, the sufficient manganese sulfide content makes its loading effect more excellent, thereby making the adsorption effect of metal ions of the modified adsorbent excellent.

[0032] Optionally, the weight ratio of acrylic acid to sodium carboxymethyl cellulose is (2.5-3.7):1; the weight ratio of acrylic acid to N,N-methylenebisacrylamide is (40-50):1; the weight ratio of acrylic acid to ammonium persulfate is (27-32):1; and the weight ratio of acrylic acid to sodium carbonate is (1-1.5):1.

[0033] Optionally, the mass ratio of sodium bisulfite to sodium carbonate is 1:(45-55).

[0034] Optionally, the heating temperature in II is 35-45℃.

[0035] Optionally, the particle size of the modified adsorbent is 0.1-5 mm.

[0036] In summary, this application has the following beneficial effects:

[0037] 1. This application provides a new approach and method for preparing battery chemical manganese dioxide using industrial manganese carbonate, a relatively purified raw material.

[0038] 2. This application uses a modified adsorbent to treat metallic impurities in industrial manganese carbonate. The modified adsorbent has the characteristics of metal adsorption, porous structure, and water-swelling properties. Under the synergistic effect of "precipitation + pore locking + resin adsorption", the content of metallic impurities is significantly reduced.

[0039] 3. In this application, manganese fluoride is coated inside the modified adsorbent and manganese sulfide is loaded outside the modified adsorbent. The modified adsorbent prepared in this way has the characteristics of excellent adsorption effect of metal impurities. Detailed Implementation

[0040] The following detailed description of this application is provided in conjunction with the embodiments. It should be noted that: unless otherwise specified, the conditions in the following embodiments are performed under conventional conditions or conditions recommended by the manufacturer. Unless otherwise specified, the raw materials used in the following embodiments are all from commercially available sources.

[0041] Preparation example of modified adsorbent

[0042] Preparation Example 1

[0043] The preparation method of the modified adsorbent is as follows:

[0044] I. Dissolve 2.80 kg of sodium carboxymethyl cellulose powder in a 15 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.175 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, 0.07 kg of manganese fluoride, and 7.0 kg of sodium carbonate. Stir to ensure that the components are evenly dispersed to obtain the initial dispersion.

[0045] II. Add 0.26 kg of ammonium persulfate and 0.15 kg of sodium bisulfite to the initial dispersion, heat and stir in a water bath at 35°C, and then keep it at the temperature and let it stand to obtain the initial product.

[0046] III. After removing the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 15.0wt% dilute hydrochloric acid at room temperature for 12 hours, then adjust the pH to neutral with sodium carbonate solution, and then wash it with deionized water.

[0047] Take 0.28 kg of manganese sulfide and disperse it in an appropriate amount of water to obtain a 20 wt% manganese sulfide dispersion. Soak the treated initial product in the 20 wt% manganese sulfide dispersion for 60 min, then take it out, wash it with water, dry it, crush it, and sieve it to obtain a modified adsorbent with a particle size of 0.1-5 mm.

[0048] Preparation Example 2

[0049] The preparation method of the modified adsorbent is as follows:

[0050] I. Dissolve 2.26 kg of sodium carboxymethyl cellulose powder in a 20 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.16 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, 0.14 kg of manganese fluoride, and 5.3 kg of sodium carbonate. Stir to ensure that the components are evenly dispersed to obtain the initial dispersion.

[0051] II. Add 0.23 kg of ammonium persulfate and 0.11 kg of sodium bisulfite to the initial dispersion, heat and stir in a water bath at 40°C, and then keep it at the temperature and let it stand to obtain the initial product.

[0052] III. After removing the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 12.5wt% dilute hydrochloric acid at room temperature for 15 hours, then adjust the pH to neutral with sodium carbonate solution, and then wash it with deionized water.

[0053] 0.42 kg of manganese sulfide was dispersed in an appropriate amount of water to obtain a 30 wt% manganese sulfide dispersion. The treated initial product was immersed in the 30 wt% manganese sulfide dispersion for 45 min, then removed, washed with water, dried, pulverized, and sieved to obtain a modified adsorbent with a particle size of 0.1-5 mm.

[0054] Preparation Example 3

[0055] The preparation method of the modified adsorbent is as follows:

[0056] I. Dissolve 1.89 kg of sodium carboxymethyl cellulose powder in a 25 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.14 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, 0.21 kg of manganese fluoride, and 4.67 kg of sodium carbonate. Stir to ensure that the components are evenly dispersed to obtain the initial dispersion.

[0057] II. Add 0.22 kg of ammonium persulfate and 0.08 kg of sodium bisulfite to the initial dispersion, heat and stir in a water bath at 45°C, and then keep it at the temperature and let it stand to obtain the initial product.

[0058] III. After removing the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 10.5wt% dilute hydrochloric acid at room temperature for 20 hours, then adjust the pH to neutral with sodium carbonate solution, and then wash it with deionized water.

[0059] Take 0.56 kg of manganese sulfide and disperse it in an appropriate amount of water to obtain a 40 wt% manganese sulfide dispersion. Soak the treated initial product in the 40 wt% manganese sulfide dispersion for 35 min, then take it out, wash it with water, dry it, crush it, and sieve it to obtain a modified adsorbent with a particle size of 0.1-5 mm.

[0060] Preparation Example 4

[0061] Compared to Preparation Example 2, the difference in this preparation example is that manganese fluoride was not added in step I; otherwise, it is the same as Preparation Example 2. Specifically, step I is as follows: 2.26 kg of sodium carboxymethyl cellulose powder is dissolved in a 20 wt% sodium hydroxide solution, cooled to room temperature, and then 7 kg of acrylic acid, 0.16 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, and 5.3 kg of sodium carbonate are added. The mixture is stirred to ensure that the components are evenly dispersed, thus obtaining an initial dispersion.

[0062] Steps II and III are the same as in Preparation Example 2.

[0063] Preparation Example 5

[0064] Compared to Preparation Example 2, the difference in this preparation example is that step III does not involve immersing the treated initial product in a 30 wt% manganese sulfide dispersion for 45 min; otherwise, it is the same as Preparation Example 2. Specifically, step III is as follows: the initial product is removed and pulverized, then washed with deionized water, soaked in anhydrous ethanol, and then washed with deionized water again; then soaked in 12.5 wt% dilute hydrochloric acid at room temperature for 15 h, then the pH is adjusted to neutral with sodium carbonate solution, and finally washed with deionized water and dried to obtain the final product.

[0065] Preparation Example 6

[0066] Compared with Preparation Example 2, the difference in this Preparation Example is that both manganese fluoride and manganese sulfide are added in step III, while the rest is the same as Preparation Example 2.

[0067] The preparation method of the modified adsorbent is as follows:

[0068] I. Dissolve 2.26 kg of sodium carboxymethyl cellulose powder in a 20 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.16 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, and 5.3 kg of sodium carbonate. Stir to ensure that the components are evenly dispersed to obtain the initial dispersion.

[0069] Step II is the same as in Preparation Example 2.

[0070] III. After removing the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 12.5wt% dilute hydrochloric acid at room temperature for 15 hours, then adjust the pH to neutral with sodium carbonate solution, and then wash it with deionized water.

[0071] Take 0.14 kg of manganese fluoride and 0.42 kg of manganese sulfide and disperse them in an appropriate amount of water to obtain a 30 wt% manganese sulfide dispersion. Soak the treated initial product in the 30 wt% manganese sulfide dispersion for 45 min, then take it out, wash it with water, dry it, crush it, and sieve it to obtain a modified adsorbent with a particle size of 0.1-5 mm.

[0072] Preparation Example 7

[0073] Compared with Preparation Example 2, the difference in this Preparation Example is that both manganese fluoride and manganese sulfide are added in step I, while the rest is the same as Preparation Example 2.

[0074] The preparation method of the modified adsorbent is as follows:

[0075] I. Dissolve 2.26 kg of sodium carboxymethyl cellulose powder in a 20 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.16 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, 0.14 kg of manganese fluoride, 0.42 kg of manganese sulfide, and 5.3 kg of sodium carbonate. Stir to ensure that all components are evenly dispersed to obtain an initial dispersion.

[0076] Step II is the same as in Preparation Example 2.

[0077] III. After taking out the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 12.5wt% dilute hydrochloric acid at room temperature for 15h, then adjust the pH to neutral with sodium carbonate solution, and then wash it with deionized water, dry it, crush it, and sieve it to obtain a modified adsorbent with a particle size of 0.1-5mm.

[0078] Preparation Example 8

[0079] Compared with Preparation Example 2, the difference in this Preparation Example is that no manganese fluoride was added in step I, and the operation of soaking the treated initial product in 30wt% manganese sulfide dispersion for 45 min was not performed in step III. Otherwise, it is the same as Preparation Example 2.

[0080] The preparation method of the modified adsorbent is as follows:

[0081] I. Dissolve 2.26 kg of sodium carboxymethyl cellulose powder in a 20 wt% sodium hydroxide solution. After cooling to room temperature, add 7 kg of acrylic acid, 0.16 kg of N,N-methylenebisacrylamide, an appropriate amount of Tween-80, and 5.3 kg of sodium carbonate. Stir to ensure that the components are evenly dispersed to obtain the initial dispersion.

[0082] II. Add 0.23 kg of ammonium persulfate and 0.10 kg of sodium bisulfite to the initial dispersion, heat and stir in a water bath at 40°C, and then keep it at the temperature and let it stand to obtain the initial product.

[0083] III. After taking out the initial product, crush it, then wash it with deionized water, soak it in anhydrous ethanol, and then wash it with deionized water again; then soak it in 12.5wt% dilute hydrochloric acid at room temperature for 15 hours, then adjust the pH to neutral with sodium carbonate solution, and then wash and dry it with deionized water to obtain the final product.

[0084] Example

[0085] Example 1

[0086] The specific steps for producing battery chemical manganese dioxide from industrial manganese carbonate are as follows:

[0087] ① Removal of impurities: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate.

[0088] The specific method is as follows:

[0089] S1. Crush 20 kg of industrial manganese carbonate into powder, then add 45 wt% sulfuric acid solution, stir thoroughly to dissolve, and obtain an acidic (pH below 7) crude manganese sulfate solution.

[0090] S2. Add 1.6 kg of modified adsorbent to the crude manganese sulfate solution, stir and adsorb for 6 h, filter to obtain a refined manganese sulfate solution; wherein, the modified adsorbent is prepared by Preparation Example 1.

[0091] S3. Add 10wt% ammonium bicarbonate solution to the high-purity manganese sulfate solution, mix to allow for full precipitation, and then filter to obtain high-purity manganese carbonate.

[0092] ② Pyrolysis: High-purity manganese carbonate is placed in a fluidized bed furnace and heated at 300°C for 120 minutes in an environment of steam and air to decompose it, yielding crude manganese dioxide. The ratio of steam to air is adjusted so that the amount of steam is 10% of the air volume.

[0093] ③ Immersion and pickling: The obtained crude manganese dioxide is placed in a dilute sulfuric acid solution, heated to 50°C and then immersed for 8 hours to further remove impurities and obtain pickled manganese dioxide.

[0094] ④ Washing: The obtained acid-washed manganese dioxide is washed with deionized water until neutral, and then dried to obtain battery chemical manganese dioxide.

[0095] Example 2

[0096] The specific steps for producing battery chemical manganese dioxide from industrial manganese carbonate are as follows:

[0097] ① Removal of impurities: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate.

[0098] The specific method is as follows:

[0099] S1. Crush 20 kg of industrial manganese carbonate into powder, then add 65 wt% sulfuric acid solution and stir thoroughly to dissolve, obtaining an acidic (pH below 7) crude manganese sulfate solution.

[0100] S2. Add 2.4 kg of modified adsorbent to the crude manganese sulfate solution, stir and adsorb for 5 h, filter to obtain a refined manganese sulfate solution; wherein, the modified adsorbent is prepared by Preparation Example 2.

[0101] S3. Add 12wt% ammonium bicarbonate solution to the high-purity manganese sulfate solution, mix to allow for full precipitation, and then filter to obtain high-purity manganese carbonate.

[0102] ② Pyrolysis: High-purity manganese carbonate is placed in a fluidized bed furnace and heated at 350°C for 80 minutes in an environment of steam and air to decompose it, yielding crude manganese dioxide. The ratio of steam to air is adjusted so that the amount of steam is 20% of the air volume.

[0103] ③ Immersion and pickling: The obtained crude manganese dioxide is placed in a dilute sulfuric acid solution, heated to 70°C and then immersed for 6 hours to further remove impurities and obtain pickled manganese dioxide.

[0104] ④ Washing: The obtained acid-washed manganese dioxide is washed with deionized water until neutral, and then dried to obtain battery chemical manganese dioxide.

[0105] Example 3

[0106] The specific steps for producing battery chemical manganese dioxide from industrial manganese carbonate are as follows:

[0107] ① Removal of impurities: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate.

[0108] The specific method is as follows:

[0109] S1. Crush 20 kg of industrial manganese carbonate into powder, then add 65 wt% sulfuric acid solution and stir thoroughly to dissolve, obtaining an acidic (pH below 7) crude manganese sulfate solution.

[0110] S2. Add 3.0 kg of modified adsorbent to the crude manganese sulfate solution, stir and adsorb for 4 h, filter to obtain a refined manganese sulfate solution; wherein, the modified adsorbent is prepared by Preparation Example 3.

[0111] S3. Add 14wt% ammonium bicarbonate solution to the high-purity manganese sulfate solution, mix to allow for full precipitation, and then filter to obtain high-purity manganese carbonate.

[0112] ② Pyrolysis: High-purity manganese carbonate is placed in a fluidized bed furnace and heated at 400°C for 30 minutes in an environment of steam and air to decompose it, yielding crude manganese dioxide. The ratio of steam to air is adjusted so that the amount of steam is 80% of the air volume.

[0113] ③ Immersion and pickling: The obtained crude manganese dioxide is placed in a dilute sulfuric acid solution, heated to 90°C and then immersed for 5 hours to further remove impurities and obtain pickled manganese dioxide.

[0114] ④ Washing: The obtained acid-washed manganese dioxide is washed with deionized water until neutral, and then dried to obtain battery chemical manganese dioxide.

[0115] Example 4

[0116] The difference between Example 4 and Example 2 is that the modified adsorbent in this example was prepared by Preparation Example 6, while the rest is the same as in Example 2.

[0117] Example 5

[0118] The difference between Example 5 and Example 2 is that the modified adsorbent in this example was prepared by Example 7, while the rest is the same as in Example 2.

[0119] Comparative Example

[0120] Comparative Example 1

[0121] The difference between this comparative example and Example 2 is that the modified adsorbent in this comparative example was prepared by Preparation Example 4, while the rest is the same as in Example 2.

[0122] Comparative Example 2

[0123] The difference between this comparative example and Example 2 is that the modified adsorbent in this comparative example was prepared by Preparation Example 5, while the rest is the same as in Example 2.

[0124] Comparative Example 3

[0125] The difference between this comparative example and Example 2 is that the modified adsorbent in this comparative example was prepared by Preparation Example 8, while the rest is the same as in Example 2.

[0126] Comparative Example 4

[0127] The difference between this comparative example and Example 2 is that this comparative example does not include the step of removing metallic impurities from industrial manganese carbonate with a modified adsorbent; otherwise, it is the same as Example 2.

[0128] Specifically, the method for producing battery chemical manganese dioxide from industrial manganese carbonate is as follows:

[0129] Step 1, Pyrolysis: Industrial manganese carbonate is placed in a fluidized bed furnace, where high-purity manganese carbonate is heated at 350°C for 80 minutes in an environment of steam and air to decompose and obtain crude manganese dioxide. The ratio of steam to air is adjusted so that the amount of steam is 20% of the air volume.

[0130] Step 2, Immersion and pickling: The obtained crude manganese dioxide is placed in a dilute sulfuric acid solution, heated to 70°C, and then immersed for 6 hours to further remove impurities and obtain pickled manganese dioxide.

[0131] Step 3, Cleaning: Wash the obtained acid-washed manganese dioxide with deionized water until neutral, and then dry it to obtain battery chemical manganese dioxide.

[0132] Comparative Example 5

[0133] The difference between this comparative example and Example 2 is that the method for removing impurities in this comparative example is different. The specific steps are as follows:

[0134] (1) Removal of impurities: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate.

[0135] The specific method is as follows:

[0136] (1-1) 20 kg of industrial manganese carbonate was crushed into powder, and then 65 wt% sulfuric acid solution was added and stirred thoroughly to dissolve, so as to obtain crude manganese sulfate solution with pH 6.

[0137] (1-2) Add 0.14 kg of manganese fluoride to the crude manganese sulfate solution, stir and react, then filter; add 0.42 kg of manganese sulfide, stir and react, then filter to obtain a refined manganese sulfate solution; wherein, the modified adsorbent is prepared by Preparation Example 2.

[0138] (1-3) Add 12wt% ammonium bicarbonate solution to the high-quality manganese sulfate solution, mix to allow for full precipitation, and then filter to obtain high-purity manganese carbonate.

[0139] The subsequent steps are the same as in Example 2.

[0140] Performance testing

[0141] The performance was tested according to the methods in the industry standard QB 2016-95 "Electrolytic Manganese Dioxide for Batteries". The specific test results are shown in Table 1.

[0142] Table 1. Battery chemistry manganese dioxide indicators obtained from different implementation schemes.

[0143]

[0144]

[0145] As shown in Table 1, the proposed method can significantly remove metallic impurities from industrial manganese carbonate, producing battery-grade manganese dioxide with low metallic impurity content. Data from Examples 2, 4, and 5 indicate that it is necessary to encapsulate manganese fluoride within the resin (i.e., mix it with the resin's raw materials such as acrylic acid, N,N-methylenebisacrylamide, and sodium carbonate) and load manganese sulfide outside the resin (i.e., immerse the initial product in a manganese sulfide dispersion) during the preparation of the modified adsorbent; otherwise, the removal efficiency of metallic impurities will be affected. Compared to iron and aluminum impurities, the raw materials contain higher levels of calcium and magnesium impurities. When the modified adsorbent prepared using the method of this application adsorbs these types of impurities, calcium and magnesium ions are precipitated and locked within the water-swellable pores of the modified adsorbent. Therefore, the adsorption and removal efficiency for substances with high calcium and magnesium impurity content is significantly improved under the synergistic effect of "precipitation + pore locking + resin adsorption." Meanwhile, the content of iron and aluminum impurities is relatively low, and excellent adsorption can be achieved by adsorbing them onto the outer surface of the modified adsorbent.

[0146] Furthermore, the data results of Examples 2 and Comparative Examples 1-2 also fully demonstrate that if manganese fluoride is not coated inside the resin or manganese sulfide is not loaded outside the resin during the preparation of the modified adsorbent, the removal effect of metal impurities will be directly affected.

[0147] In Comparative Example 3, using resin as an adsorbent only had a certain effect on removing metal impurities, but the removal effect on metal ions was poor. Comparative Example 4, which did not include any impurity removal step, directly prepared battery chemical manganese dioxide from industrial manganese carbonate, resulting in a high content of metal impurities. The data from Comparative Example 5 indicate that using only a precipitant for impurity removal is also limited in effectiveness; only the "resin + precipitant" approach demonstrates significantly superior impurity removal performance.

[0148] This specific embodiment is merely an explanation of this application and is not intended to limit it. After reading this specification, those skilled in the art can make modifications to this embodiment without contributing any inventive step, but such modifications are protected by patent law as long as they fall within the scope of the claims of this application.

Claims

1. A method for producing battery chemical manganese dioxide from industrial manganese carbonate, characterized in that, Includes the following steps: ① Impurity removal: Remove metallic impurities from industrial manganese carbonate to obtain high-purity manganese carbonate; ② Pyrolysis: The high-purity manganese carbonate is placed in an environment of water vapor and air and heated to decompose it, yielding crude manganese dioxide; ③ Immersion and pickling: The crude manganese dioxide is placed in a sulfuric acid solution and heated for immersion treatment to obtain pickled manganese dioxide; ④ Cleaning: The acid-washed manganese dioxide is washed with water until neutral, and then dried to obtain battery chemical manganese dioxide; In ①, a modified adsorbent is used to remove metallic impurities from industrial manganese carbonate; the modified adsorbent is obtained by loading a precipitant onto a water-absorbing porous adsorption resin, and the precipitant includes manganese sulfide and manganese fluoride. The preparation method of the modified adsorbent includes the following steps: I. Dissolve sodium carboxymethyl cellulose powder in an alkaline solution, cool to room temperature, and then add acrylic acid, N,N-methylenebisacrylamide, surfactant, manganese fluoride, and sodium carbonate. After uniform dispersion, an initial dispersion is obtained. II. Add ammonium persulfate and sodium bisulfite to the initial dispersion, heat and stir, and then let stand to obtain the initial product; III. After taking out the initial product, crush it, wash it, soak it in hydrochloric acid, wash it with water, and finally soak it in manganese sulfide dispersion, take it out, wash it with water, and dry it to obtain the modified adsorbent. The weight ratio of acrylic acid to manganese fluoride is 1:(0.01-0.03); the weight ratio of acrylic acid to manganese sulfide is 1:(0.04-0.08). The method for removing impurities in ① includes the following steps: S1. After crushing industrial manganese carbonate, add sulfuric acid solution to obtain crude manganese sulfate solution; S2. The crude manganese sulfate solution and the modified adsorbent are mixed and filtered to obtain a refined manganese sulfate solution. The amount of the modified adsorbent added is 8-15 wt% of the industrial manganese carbonate. S3. Mix the refined manganese sulfate solution and ammonium bicarbonate solution, filter, and obtain high-purity manganese carbonate. Among them, the amount of water vapor in ② is 10-80 Vol.% of that in air.

2. The method for producing battery chemical manganese dioxide from industrial manganese carbonate according to claim 1, characterized in that, ② The temperature for heating and decomposition is 300-400℃, and the heating and decomposition time is 30-120min.

3. The method for producing battery chemical manganese dioxide from industrial manganese carbonate according to claim 1, characterized in that, ② The heating and decomposition operation is carried out in a fluidized bed furnace.

4. The method for producing battery chemical manganese dioxide from industrial manganese carbonate according to claim 1, characterized in that, ③ The soaking time is 5-8 hours, and the heating temperature is 50-90℃.

5. A method for producing battery chemical manganese dioxide from industrial manganese carbonate according to claim 1, characterized in that, The heating temperature in section II is 35-45℃.

6. A method for producing battery chemical manganese dioxide from industrial manganese carbonate according to claim 1, characterized in that, The modified adsorbent has a particle size of 0.1-5 mm.

Images