A process for the preparation of technical grade manganese carbonate using recycled manganese chloride solution

Abstract

The present application relates to the technical field of manganese-containing wastewater resource recycling, and particularly relates to a process for preparing industrial-grade manganese carbonate by using recycled manganese chloride solution, which adopts a two-stage purification and impurity removal strategy, i.e., one-stage purification and impurity removal by using sodium sulfide and sodium fluoride, and two-stage impurity removal by using imino-diacetic acid grafted chelating resin, and then the obtained purified solution is reacted with sodium carbonate, filtered and washed to obtain industrial-grade manganese carbonate, thereby solving the problems of poor adaptability and incomplete impurity removal of the existing process when facing manganese chloride solution, significantly improving the purity of the product to meet the requirements of industrial-grade manganese carbonate, and simplifying the process flow.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of manganese-containing wastewater resource recycling, in particular to a process for preparing industrial-grade manganese carbonate by using recycled manganese chloride solution. BACKGROUND

[0002] In the recycling of lithium battery cathode materials, alloy smelting and organic chemical catalytic processes, manganese chloride waste liquid often appears, which is directly discharged or buried, not only causing waste of manganese resources, but also threatening the natural environment. Industrial-grade manganese carbonate is widely used in soft magnetic ferrite manufacturing, ceramic glaze and fertilizer, and in recent years, with the development of battery materials, it is also applied to lithium battery cathode materials, and its market demand is stable. At present, the process for preparing manganese carbonate is mostly high-purity manganese salt, such as using manganese sulfate and carbonate, which has high cost and limited raw materials. The recycled manganese chloride waste liquid has complex composition and large fluctuation of impurity content. Therefore, it is necessary to develop an efficient and universal process for preparing industrial-grade manganese carbonate from recycled manganese chloride solution. SUMMARY

[0003] The present application provides a process for preparing industrial-grade manganese carbonate by using recycled manganese chloride solution, which adopts a two-stage purification and impurity removal strategy. Sodium sulfide and sodium fluoride are used for one-stage purification and impurity removal, and iminodiacetic acid grafted chelating resin is used for two-stage impurity removal. The obtained purified liquid is reacted with sodium carbonate, filtered and washed to obtain industrial-grade manganese carbonate. The process solves the problems of poor adaptability and incomplete impurity removal of existing processes when facing manganese chloride solution, significantly improves the purity of the product to meet the requirements of industrial-grade manganese carbonate, and the process flow is simple.

[0004] The present application can be realized by the following technical scheme: a process for preparing industrial-grade manganese carbonate by using recycled manganese chloride solution, comprising the following steps:

[0005] Step S1: mix the recycled manganese chloride solution and sodium sulfide, stir for 10-15 min at room temperature, then add sodium fluoride and continue to stir for 15-20 min, filter to obtain a one-stage purified liquid. The addition amount of sodium sulfide is 0.08-0.12% of the mass of the recycled manganese chloride solution, and the addition amount of sodium fluoride is 0.04-0.06% of the mass of the recycled manganese chloride solution;

[0006] Step S2: adding hydrochloric acid solution to the primary purified solution, adjusting the pH value to 3-3.5, then adding hydrogen peroxide, stirring for 3-5 min at room temperature, and then adding imino diacetic acid grafted chelating resin, adsorbing for 45-60 min to obtain a secondary purified solution, wherein the mass fraction of the hydrochloric acid solution is 10%, the mass fraction of the hydrogen peroxide is 30%, the amount of the imino diacetic acid grafted chelating resin is 2.5-4% of the mass of the purified solution, and the amount of the hydrogen peroxide is 0.03-0.05% of the mass of the purified solution;

[0007] Step S3: adding sodium carbonate solution to the secondary purified solution, adjusting the pH value to 7, and transferring to a reaction kettle, and reacting for 40-60 min at a temperature of 70°C, wherein the pH value in the reaction process is adjusted to 6.8-7.2 by controlling the amount of sodium carbonate added, to obtain crude manganese carbonate, wherein the mass fraction of the sodium carbonate solution is 20%, and the amount of sodium carbonate is calculated according to the manganese content, and the molar ratio of carbonate to manganese ions is 1:1.05;

[0008] Step S4: aging the crude manganese carbonate at a temperature of 60-70°C for 1.5-2 h, washing with deionized water until the conductivity of the filtrate is <100 μS / cm, and then drying at a temperature of 105-115°C for 4-6 h, and crushing through a 325 mesh sieve to obtain industrial-grade manganese carbonate.

[0009] The reaction process is shown in Figure 1 .

[0010] The imino diacetic acid grafted chelating resin is prepared by the following steps:

[0011] Step A1: mixing methacrylic acid, potassium carbonate and N,N-dimethylformamide, stirring at a stirring rate of 120-150 rpm at room temperature for 25-30 min, then adding 1-(4-bromobutoxy)-4-methoxybenzene, and reacting for 6-7 h, and then filtering, washing with dichloromethane, concentrating the filtrate, to obtain an intermediate monomer, mixing p-dimethoxybenzene, the intermediate monomer, paraformaldehyde and 1,2-dichloroethane, stirring at a stirring rate of 120-150 rpm at room temperature for 8-10 min, then adding boron trifluoride etherate, and reacting for 5 h, adding deionized water to quench the reaction, extracting the organic phase with chloroform / deionized water, spinning to dryness, and chromatographing with petroleum ether / ethyl acetate to obtain a column [5] arene intermediate;

[0012] Further, in step A1: the ratio of methacrylic acid, potassium carbonate, N,N-dimethylformamide and 1-(4-bromobutoxy)-4-methoxybenzene is 0.85-0.9g: 1.4-1.5g: 25-30mL: 2.5-2.6g; the ratio of p-dimethoxybenzene, intermediate monomer, paraformaldehyde, 1,2-dichloroethane and boron trifluoride ethyl ether is 1.1-1.15g: 0.52-0.53g: 0.9-1g: 145-150mL: 2.8-2.85g; the mass fraction of paraformaldehyde is 97%; and the volume ratio of petroleum ether / ethyl acetate in the petroleum ether / ethyl acetate system is 4:1.

[0013] Step A2: Chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine and N,N-dimethylformamide are mixed and reacted for 3-4 hours under nitrogen protection, stirring at 100-120 rpm and at 60℃. Then glycidyl methacrylate is added and the reaction continues for 10-12 hours. The mixture is washed with acetone, ethylenediaminetetraacetic acid solution, methanol, and deionized water, and dried to obtain grafted polystyrene microspheres.

[0014] Further, in step A2: the ratio of chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine, and N,N-dimethylformamide glycidyl methacrylate is 6.5-6.8g: 0.84-0.85g: 0.22-0.23g: 0.74-0.75g: 100-120mL: 10-12mL.

[0015] Step A3: Mix iminodiacetic acid, sodium carbonate and deionized water, stir and add sodium hydroxide solution to adjust the pH to 10.5, then add grafted polystyrene microspheres and methanol, and react for 10-12 h at a stirring rate of 50-60 rpm and a temperature of 80℃. Wash with deionized water, ethanol and acetone, and dry to obtain iminodiacetic acid grafted chelating resin.

[0016] Furthermore, in step A3: the ratio of iminodiacetic acid, sodium carbonate, deionized water, grafted polystyrene microspheres and methanol is 1.32-1.35g: 4.8-5.2g: 25-30mL: 3.5-3.8g: 25-30mL, and the sodium hydroxide solution has a mass fraction of 10%.

[0017] Furthermore, in the preparation process of iminodiacetic acid grafted chelate resin, bromine in 1-(4-bromobutoxy)-4-methoxybenzene reacts with methacrylic acid to form an ester group, and an intermediate monomer is obtained. Then, using p-dimethoxybenzene and the intermediate monomer as monomers, a condensation cyclization reaction is carried out with paraformaldehyde under the action of boron trifluoride ether to form a columnar aromatic structure, and a columnar[5] aromatic intermediate is obtained. Using chloromethyl in chloromethyl polystyrene resin as a macromolecular initiator site, through atom transfer radical polymerization, its chloromethyl first reacts with the columnar[5] aromatic intermediate, and then continues to react with glycidyl methacrylate to obtain grafted polystyrene microspheres. The epoxy group in the grafted polystyrene microspheres then reacts with iminodiacetic acid to obtain iminodiacetic acid grafted chelate resin. The reaction process can be referred to Figure 2 and Figure 3 .

[0018] Compared with the prior art, the beneficial effects of the present invention are as follows:

[0019] 1. The purpose of this invention is to provide a process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution. This process employs a two-stage purification strategy: primary purification using sodium sulfide and sodium fluoride, secondary purification using iminodiacetic acid-grafted chelating resin, followed by reaction of the purified solution with sodium carbonate, filtration, and washing to obtain industrial-grade manganese carbonate. This solves the problems of poor adaptability and incomplete impurity removal in existing processes when dealing with manganese chloride solution, significantly improving the purity of the product to meet the requirements of industrial-grade manganese carbonate, and the process flow is simple.

[0020] 2. In the purification and impurity removal process of this invention, sodium sulfide and sodium fluoride are used for the first purification and impurity removal. Sodium sulfide introduces sulfur ions, which react with iron ions to form a colloidal precipitate. Sodium fluoride is then added to precipitate calcium ions, thereby performing the first purification and impurity removal to remove most of the impurity ions. At the same time, in the second purification and impurity removal process, hydrogen peroxide is used as an oxidant and controlled under acidic conditions. Under acidic conditions, ferrous ions are oxidized to ferric ions. At the same time, acidic conditions prevent the oxidation of manganese ions. The columnar [5] aromatic structure and iminodiacetic acid group introduced in the iminodiacetic acid grafted chelating resin can preferentially recognize and accommodate ferric ions through size exclusion and specific interaction of the columnar [5] aromatic structure, and through acidic conditions... Under the condition of specific binding of iminodiacetic acid group with ferric ions, while removing impurity ions, the binding of manganese ions with iminodiacetic acid graft chelating resin is minimized, thereby improving the purity of subsequent manganese carbonate preparation to meet the requirements of industrial-grade manganese carbonate. At the same time, since the iminodiacetic acid graft chelating resin itself is prepared with chloromethyl polystyrene resin as the matrix, it is matched with the column[5] aromatic structure and has a large adsorption capacity. It can maintain good performance after multiple uses without washing and removal. The impurity ions of the secondary purification liquid after secondary impurity removal are completely removed. The crude manganese carbonate formed after reacting with sodium carbonate can meet the requirements of industrial-grade manganese carbonate after simple washing, drying and crushing. Attached Figure Description

[0021] Figure 1 This is a process flow diagram of the present invention;

[0022] Figure 2 This is a schematic diagram of the reaction in step A1 of the present invention;

[0023] Figure 3 This is a schematic diagram of the reaction in steps A2 and A3 of the present invention. Detailed Implementation

[0024] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0025] Example 1

[0026] A process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution includes the following steps: Step S1: Mix the recycled manganese chloride solution and sodium sulfide, stir for 10 min at room temperature, then add sodium fluoride, continue stirring for 15 min, filter, and obtain a primary purified solution, wherein the amount of sodium sulfide added is 0.08% of the mass of the recycled manganese chloride solution, and the amount of sodium fluoride added is 0.04% of the mass of the recycled manganese chloride solution;

[0027] Step S2: Add hydrochloric acid solution to the primary purification solution to adjust the pH to 3, then add hydrogen peroxide. Stir for 3 minutes at room temperature, then add iminodiacetic acid grafted chelating resin and adsorb for 45 minutes to obtain the secondary purification solution. The hydrochloric acid solution has a mass fraction of 10%, the hydrogen peroxide has a mass fraction of 30%, the iminodiacetic acid grafted chelating resin has a mass of 2.5% of the purification solution mass, and the hydrogen peroxide has a mass of 0.03% of the purification solution mass.

[0028] Step S3: Add sodium carbonate solution to the secondary purification liquid, adjust the pH value to 7, transfer to a reaction vessel, and react at 70℃ for 60 min. By controlling the amount of sodium carbonate added, the pH value during the reaction is adjusted to 6.8 to obtain crude manganese carbonate with a sodium carbonate solution mass fraction of 20%. The amount of sodium carbonate used is calculated based on the manganese content, and the molar ratio of carbonate ions to manganese ions is 1:1.05.

[0029] Step S4: The crude manganese carbonate is aged at 60℃ for 2 hours, washed with deionized water until the conductivity of the filtrate is <100μS / cm, dried at 105℃ for 6 hours, and then pulverized through a 325-mesh sieve to obtain industrial-grade manganese carbonate.

[0030] See reaction procedure Figure 1 .

[0031] Furthermore, the recovered manganese chloride solution used contained 120 g / L of manganese ions, 0.14 g / L of iron ions, and 0.072 g / L of calcium ions.

[0032] The iminodiacetic acid-grafted chelating resin is prepared by the following steps:

[0033] Step A1: Mix methacrylic acid, potassium carbonate and N,N-dimethylformamide, stir for 25 min at room temperature with a stirring speed of 120 rpm, then add 1-(4-bromobutoxy)-4-methoxybenzene, react for 6 h, filter, wash with dichloromethane, concentrate the filtrate to obtain intermediate monomer, mix p-dimethoxybenzene, intermediate monomer, paraformaldehyde and 1,2-dichloroethane, stir for 8 min at room temperature with a stirring speed of 120 rpm, then add boron trifluoride ether, react for 5 h, add deionized water to quench the reaction, extract the organic phase with chloroform / deionized water, evaporate to dryness, and precipitate with petroleum ether / ethyl acetate to obtain column [5] aromatic intermediate;

[0034] Furthermore, in step A1: the ratio of methacrylic acid, potassium carbonate, N,N-dimethylformamide, and 1-(4-bromobutoxy)-4-methoxybenzene is 0.85g:1.4g:25mL:2.5g; the ratio of p-dimethoxybenzene, intermediate monomer, paraformaldehyde, 1,2-dichloroethane, and boron trifluoride ethyl ether is 1.1g:0.52g:0.9g:145mL:2.8g; the mass fraction of paraformaldehyde is 97%; and the volume ratio of petroleum ether / ethyl acetate in the petroleum ether / ethyl acetate system is 4:1.

[0035] Step A2: Chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine and N,N-dimethylformamide were mixed and reacted for 3 h under nitrogen protection, stirring at 120 rpm and at 60 °C. Then glycidyl methacrylate was added and the reaction continued for 10 h. The mixture was washed with acetone, ethylenediaminetetraacetic acid solution, methanol, and deionized water, and dried to obtain grafted polystyrene microspheres.

[0036] Furthermore, in step A2: the ratio of chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine, and N,N-dimethylformamide glycidyl methacrylate is 6.5g:0.85g:0.22g:0.74g:120mL:10mL;

[0037] Step A3: Mix iminodiacetic acid, sodium carbonate and deionized water, stir and add sodium hydroxide solution to adjust the pH to 10.5, then add grafted polystyrene microspheres and methanol, and react for 12 h at a stirring rate of 50 rpm and a temperature of 80 °C. Wash with deionized water, ethanol and acetone, and dry to obtain iminodiacetic acid grafted chelating resin.

[0038] Furthermore, in step A3: the ratio of iminodiacetic acid, sodium carbonate, deionized water, grafted polystyrene microspheres and methanol is 1.32g:4.8g:25mL:3.8g:25mL, and the sodium hydroxide solution has a mass fraction of 10%.

[0039] The reaction process can be referenced. Figure 2 and Figure 3 .

[0040] Example 2

[0041] A process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution includes the following steps: Step S1: Mix the recycled manganese chloride solution and sodium sulfide, stir for 15 min at room temperature, then add sodium fluoride, continue stirring for 15 min, filter, and obtain a primary purified solution. The amount of sodium sulfide added is 0.12% of the mass of the recycled manganese chloride solution, and the amount of sodium fluoride added is 0.04% of the mass of the recycled manganese chloride solution.

[0042] Step S2: Add hydrochloric acid solution to the primary purification solution to adjust the pH to 3.5, then add hydrogen peroxide, stir for 3 minutes at room temperature, then add iminodiacetic acid grafted chelating resin, and adsorb for 45 minutes to obtain the secondary purification solution. The hydrochloric acid solution has a mass fraction of 10%, the hydrogen peroxide has a mass fraction of 30%, the iminodiacetic acid grafted chelating resin has a mass of 4% of the purification solution, and the hydrogen peroxide has a mass of 0.05% of the purification solution.

[0043] Step S3: Add sodium carbonate solution to the secondary purification liquid, adjust the pH value to 7, transfer to a reaction vessel, and react at 70℃ for 40 min. By controlling the amount of sodium carbonate added, the pH value during the reaction is adjusted to 6.8 to obtain crude manganese carbonate with a sodium carbonate solution mass fraction of 20%. The amount of sodium carbonate used is calculated based on the manganese content, and the molar ratio of carbonate ions to manganese ions is 1:1.05.

[0044] Step S4: The crude manganese carbonate is aged for 1.5 hours at 60°C, washed with deionized water until the conductivity of the filtrate is <100μS / cm, dried for 4 hours at 105°C, and then pulverized through a 325-mesh sieve to obtain industrial-grade manganese carbonate.

[0045] Furthermore, the recovered manganese chloride solution used contained 80 g / L of manganese ions, 0.12 g / L of iron ions, and 0.070 g / L of calcium ions.

[0046] See reaction procedure Figure 1 .

[0047] The iminodiacetic acid-grafted chelating resin is prepared by the following steps:

[0048] Step A1: Mix methacrylic acid, potassium carbonate and N,N-dimethylformamide, stir for 25 min at room temperature with a stirring speed of 150 rpm, then add 1-(4-bromobutoxy)-4-methoxybenzene, react for 6 h, filter, wash with dichloromethane, concentrate the filtrate to obtain intermediate monomer, mix p-dimethoxybenzene, intermediate monomer, paraformaldehyde and 1,2-dichloroethane, stir for 8 min at room temperature with a stirring speed of 150 rpm, then add boron trifluoride ether, react for 5 h, add deionized water to quench the reaction, extract the organic phase with chloroform / deionized water, evaporate to dryness, and precipitate with petroleum ether / ethyl acetate to obtain column [5] aromatic intermediate;

[0049] Furthermore, in step A1: the ratio of methacrylic acid, potassium carbonate, N,N-dimethylformamide, and 1-(4-bromobutoxy)-4-methoxybenzene is 0.9 g: 1.4 g: 30 mL: 2.5 g; the ratio of p-dimethoxybenzene, intermediate monomer, paraformaldehyde, 1,2-dichloroethane, and boron trifluoride ethyl ether is 1.15 g: 0.52 g: 0.9 g: 150 mL: 2.8 g; the mass fraction of paraformaldehyde is 97%; and the volume ratio of petroleum ether / ethyl acetate in the petroleum ether / ethyl acetate system is 4:1.

[0050] Step A2: Chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine and N,N-dimethylformamide were mixed and reacted for 4 h under nitrogen protection, stirring at 100 rpm and at 60 °C. Then glycidyl methacrylate was added and the reaction continued for 10 h. The mixture was washed with acetone, ethylenediaminetetraacetic acid solution, methanol, and deionized water, and dried to obtain grafted polystyrene microspheres.

[0051] Furthermore, in step A2: the ratio of chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine, and N,N-dimethylformamide glycidyl methacrylate is 6.5g:0.84g:0.22g:0.75g:100mL:10mL;

[0052] Step A3: Mix iminodiacetic acid, sodium carbonate and deionized water, stir and add sodium hydroxide solution to adjust the pH to 10.5, then add grafted polystyrene microspheres and methanol, and react for 10 h at a stirring rate of 50 rpm and a temperature of 80 °C. Wash with deionized water, ethanol and acetone, and dry to obtain iminodiacetic acid grafted chelating resin.

[0053] Furthermore, in step A3: the ratio of iminodiacetic acid, sodium carbonate, deionized water, grafted polystyrene microspheres and methanol is 1.32g:4.8g:25mL:3.5g:25mL, and the sodium hydroxide solution has a mass fraction of 10%.

[0054] The reaction process can be referenced. Figure 2 and Figure 3 .

[0055] Example 3

[0056] A process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution includes the following steps: Step S1: Mix the recycled manganese chloride solution and sodium sulfide, stir for 15 min at room temperature, then add sodium fluoride, continue stirring for 20 min, filter, and obtain a primary purified solution. The amount of sodium sulfide added is 0.12% of the mass of the recycled manganese chloride solution, and the amount of sodium fluoride added is 0.06% of the mass of the recycled manganese chloride solution.

[0057] Step S2: Add hydrochloric acid solution to the primary purification solution to adjust the pH to 3.5, then add hydrogen peroxide, stir for 5 minutes at room temperature, then add iminodiacetic acid grafted chelating resin, and adsorb for 60 minutes to obtain the secondary purification solution. The hydrochloric acid solution has a mass fraction of 10%, the hydrogen peroxide has a mass fraction of 30%, the iminodiacetic acid grafted chelating resin has a mass of 4% of the purification solution, and the hydrogen peroxide has a mass of 0.05% of the purification solution.

[0058] Step S3: Add sodium carbonate solution to the secondary purification liquid, adjust the pH value to 7, transfer to a reaction vessel, and react at 70℃ for 60 min. By controlling the amount of sodium carbonate added, the pH value during the reaction is adjusted to 7.2 to obtain crude manganese carbonate with a sodium carbonate solution mass fraction of 20%. The amount of sodium carbonate used is calculated based on the manganese content, and the molar ratio of carbonate ions to manganese ions is 1:1.05.

[0059] Step S4: At a temperature of 70℃, the crude manganese carbonate is aged for 2 hours, washed with deionized water until the conductivity of the filtrate is <100μS / cm, and then dried at a temperature of 115℃ for 4-6 hours. The filtrate is then pulverized and passed through a 325-mesh sieve to obtain industrial-grade manganese carbonate.

[0060] Furthermore, the recovered manganese chloride solution used contained 112 g / L of manganese ions, 0.13 g / L of iron ions, and 0.074 g / L of calcium ions.

[0061] See reaction procedure Figure 1 .

[0062] The iminodiacetic acid-grafted chelating resin is prepared by the following steps:

[0063] Step A1: Mix methacrylic acid, potassium carbonate and N,N-dimethylformamide, stir for 30 min at room temperature with a stirring speed of 150 rpm, then add 1-(4-bromobutoxy)-4-methoxybenzene, react for 7 h, filter, wash with dichloromethane, concentrate the filtrate to obtain intermediate monomer, mix p-dimethoxybenzene, intermediate monomer, paraformaldehyde and 1,2-dichloroethane, stir for 10 min at room temperature with a stirring speed of 150 rpm, then add boron trifluoride ether, react for 5 h, add deionized water to quench the reaction, extract the organic phase with chloroform / deionized water, evaporate to dryness, and precipitate with petroleum ether / ethyl acetate to obtain column [5] aromatic intermediate;

[0064] Furthermore, in step A1: the ratio of methacrylic acid, potassium carbonate, N,N-dimethylformamide, and 1-(4-bromobutoxy)-4-methoxybenzene is 0.9g:1.5g:30mL:2.6g; the ratio of p-dimethoxybenzene, intermediate monomer, paraformaldehyde, 1,2-dichloroethane, and boron trifluoride ethyl ether is 1.15g:0.53g:1g:150mL:2.85g; the mass fraction of paraformaldehyde is 97%; and the volume ratio of petroleum ether / ethyl acetate in the petroleum ether / ethyl acetate system is 4:1.

[0065] Step A2: Chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine and N,N-dimethylformamide were mixed and reacted for 4 h under nitrogen protection, stirring at 120 rpm and at 60 °C. Then glycidyl methacrylate was added and the reaction continued for 12 h. The mixture was washed with acetone, ethylenediaminetetraacetic acid solution, methanol, and deionized water, and dried to obtain grafted polystyrene microspheres.

[0066] Furthermore, in step A2: the ratio of chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine, and N,N-dimethylformamide glycidyl methacrylate is 6.8g:0.85g:0.23g:0.75g:120mL:12mL;

[0067] Step A3: Mix iminodiacetic acid, sodium carbonate and deionized water, stir and add sodium hydroxide solution to adjust the pH to 10.5, then add grafted polystyrene microspheres and methanol, and react for 12 h at a stirring rate of 60 rpm and a temperature of 80 °C. Wash with deionized water, ethanol and acetone, and dry to obtain iminodiacetic acid grafted chelating resin.

[0068] Furthermore, in step A3: the ratio of iminodiacetic acid, sodium carbonate, deionized water, grafted polystyrene microspheres and methanol is 1.35g:5.2g:30mL:3.8g:30mL, and the sodium hydroxide solution has a mass fraction of 10%.

[0069] The reaction process can be referenced. Figure 2 and Figure 3 .

[0070] Example 4

[0071] This embodiment uses the same batch of recovered manganese chloride solution as in Example 3. Without changing the iminodiacetic acid grafted chelating resin, the process flow of Example 3 is carried out 5 times. The industrial-grade manganese carbonate obtained in the fifth process flow is used as the product obtained in this embodiment. Other steps are the same.

[0072] Comparative Example 1

[0073] Compared with Example 3, this comparative example uses the same batch of recovered manganese chloride solution, but replaces the iminodiacetic acid grafted chelating resin in the secondary purification process of step S2 in Example 3 with commercially available chloromethyl polystyrene resin, while the other steps are the same.

[0074] Comparative Example 2

[0075] Compared with Example 3, this comparative example uses the same batch of recycled manganese chloride solution, but replaces the hydrogen peroxide solution in step S2 of Example 3 with deionized water, while the other steps are the same.

[0076] Comparative Example 3

[0077] Compared with Example 4, this comparative example uses the same batch of recovered manganese chloride solution, but replaces the iminodiacetic acid grafted chelating resin in the secondary purification process of step S2 in Example 3 with commercially available Lewatit MonoPlusTP207 chelating resin, while the other steps are the same.

[0078] Industrial-grade manganese carbonate prepared in Examples 1, 2, 3, 4, Comparative Examples 1, 2, and 3 was used to determine the manganese, iron, calcium, and chlorine content. The results are shown in Table 1 below.

[0079] Table 1 Content Determination Table

[0080]

[0081] Taking Examples 3, 4, Comparative Examples 1, 2, and 3 as examples, the manganese recovery rate was determined under the condition that 10L of manganese chloride recovery solution was used. The results are shown in Table 2 below:

[0082] Table 2 Recovery Rate Determination Table

[0083]

[0084] As can be seen from Tables 1 and 2 above, comparing Example 3 with Comparative Example 1, after replacing the iminodiacetic acid grafted chelating resin with commercially available chloromethyl polystyrene resin, the impurity content of the obtained manganese carbonate increased significantly. Simultaneously, due to the adsorption effect of chloromethyl polystyrene resin on manganese ions, the manganese recovery rate decreased significantly. Comparing Example 3 with Comparative Example 2, the lack of a hydrogen peroxide oxidation step prevented the oxidation of ferrous ions to ferric ions, resulting in their inability to specifically bind with the subsequent iminodiacetic acid grafted chelating resin. This not only led to an increase in iron impurity content to some extent, but the lack of specific binding also caused manganese ions to bind with the iminodiacetic acid grafted chelating resin, thus affecting the manganese recovery rate. According to the data obtained from Example 4 and Comparative Example 3, after multiple uses, the impurity ion content increased significantly, while the manganese recovery rate decreased to some extent. This indicates that the iminodiacetic acid grafted chelating resin prepared in this invention has a large adsorption capacity and can avoid the decrease in manganese recovery rate caused by the binding of manganese ions with the chelating resin during use.

[0085] In the description of this specification, the references to terms such as "an embodiment," "example," "specific example," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0086] The above content is merely an example and illustration of the concept of the present invention. Those skilled in the art can make various modifications or additions to the specific embodiments described or use similar methods to replace them, as long as they do not deviate from the concept of the invention, they should all fall within the protection scope of the present invention.

Claims

1. A process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution, characterized in that: Includes the following steps: Step S1: Mix the recovered manganese chloride solution and sodium sulfide, stir for 10-15 minutes at room temperature, then add sodium fluoride, continue stirring for 15-20 minutes, filter, and obtain the first purified solution; Step S2: Add hydrochloric acid solution to the primary purification solution to adjust the pH value to 3-3.5, then add hydrogen peroxide, stir for 3-5 minutes at room temperature, then add iminodiacetic acid grafted chelating resin and adsorb for 45-60 minutes to obtain the secondary purification solution. Step S3: Add sodium carbonate solution to the secondary purification liquid, adjust the pH value to 7, transfer to a reaction vessel, and react at 70℃ for 40-60 minutes. By controlling the amount of sodium carbonate added, the pH value during the reaction is adjusted to 6.8-7.2 to obtain crude manganese carbonate. Step S4: At a temperature of 60-70℃, the crude manganese carbonate is aged for 1.5-2 hours, washed with deionized water until the conductivity of the filtrate is <100μS / cm, and then dried at a temperature of 105-115℃ for 4-6 hours. The filtrate is then pulverized and passed through a 325-mesh sieve to obtain industrial-grade manganese carbonate. The iminodiacetic acid-grafted chelating resin is prepared by the following steps: Step A1: Mix methacrylic acid, potassium carbonate and N,N-dimethylformamide, stir at a stirring rate of 120-150 rpm at room temperature for 25-30 min, then add 1-(4-bromobutoxy)-4-methoxybenzene, react for 6-7 h, filter, wash with dichloromethane, concentrate the filtrate to obtain intermediate monomer, mix p-dimethoxybenzene, intermediate monomer, paraformaldehyde and 1,2-dichloroethane, stir at a stirring rate of 120-150 rpm at room temperature for 8-10 min, then add boron trifluoride ether, react for 5 h, add deionized water to quench the reaction, extract the organic phase with chloroform / deionized water, evaporate to dryness, and precipitate with petroleum ether / ethyl acetate to obtain column [5] aromatic intermediate; Step A2: Chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine and N,N-dimethylformamide are mixed and reacted for 3-4 hours under nitrogen protection, stirring at 100-120 rpm and at 60℃. Then glycidyl methacrylate is added and the reaction continues for 10-12 hours. The mixture is washed with acetone, ethylenediaminetetraacetic acid solution, methanol, and deionized water, and dried to obtain grafted polystyrene microspheres. Step A3: Mix iminodiacetic acid, sodium carbonate and deionized water, stir and add sodium hydroxide solution to adjust the pH to 10.5, then add grafted polystyrene microspheres and methanol, and react for 10-12 h at a stirring rate of 50-60 rpm and a temperature of 80℃. Wash with deionized water, ethanol and acetone, and dry to obtain iminodiacetic acid grafted chelating resin.

2. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step S1: the amount of sodium sulfide added is 0.08-0.12% of the mass of the recovered manganese chloride solution, and the amount of sodium fluoride added is 0.04-0.06% of the mass of the recovered manganese chloride solution.

3. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step S2: the hydrochloric acid solution has a mass fraction of 10%, the hydrogen peroxide has a mass fraction of 30%, the composite chelating resin has a mass of 2.5-4% of the purification solution mass, and the hydrogen peroxide has a mass of 0.03-0.05% of the purification solution mass.

4. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step S3: the sodium carbonate solution has a mass fraction of 20%, and the amount of sodium carbonate used is calculated based on the manganese content, wherein the molar ratio of carbonate ions to manganese ions is 1:1.

05.

5. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step A1: the ratio of methacrylic acid, potassium carbonate, N,N-dimethylformamide, and 1-(4-bromobutoxy)-4-methoxybenzene is 0.85-0.9g: 1.4-1.5g: 25-30mL: 2.5-2.6g; the ratio of p-dimethoxybenzene, intermediate monomer, paraformaldehyde, 1,2-dichloroethane, and boron trifluoride ethyl ether is 1.1-1.15g: 0.52-0.53g: 0.9-1g: 145-150mL: 2.8-2.85g; the mass fraction of paraformaldehyde is 97%; and the volume ratio of petroleum ether to ethyl acetate in the petroleum ether / ethyl acetate system is 4:

1.

6. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step A2, the ratio of the following components is as follows: chloromethyl polystyrene resin, columnar aromatic intermediate [5], copper bromide, 2,2-bipyridine, and N,N-dimethylformamide glycidyl methacrylate is 6.5-6.8g: 0.84-0.85g: 0.22-0.23g: 0.74-0.75g: 100-120mL: 10-12mL.

7. The process for preparing industrial-grade manganese carbonate using recycled manganese chloride solution according to claim 1, characterized in that: In step A3, the ratio of iminodiacetic acid, sodium carbonate, deionized water, grafted polystyrene microspheres, and methanol is 1.32-1.35g: 4.8-5.2g: 25-30mL: 3.5-3.8g: 25-30mL, and the sodium hydroxide solution has a mass fraction of 10%.

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