A method for removing heavy metal ions from manganese sulfate solution

Abstract

This invention relates to the field of electrolytic manganese technology, specifically a method for removing heavy metal ions from manganese sulfate solution. The method includes the following steps: compounding lignin with MnO2; preparing a modified lignin flocculant; pretreating the manganese sulfate solution; and treating the manganese sulfate solution with the modified lignin composite flocculant. This invention, by compounding lignin with MnO2 and preparing the resulting lignin / MnO2 composite material into a modified lignin flocculant, forms a porous structure conducive to the adsorption of heavy metal ions while retaining the basic structure of lignin. Furthermore, the compounding with MnO2 increases the hydroxyl adsorption sites of the modified lignin flocculant, further enhancing its adsorption capacity for heavy metal ions and significantly reducing the heavy ion content in the manganese sulfate solution.

Description

Technical Field

[0001] This invention relates to the field of electrolytic manganese technology, specifically a method for removing heavy metal ions from manganese sulfate solution. Background Technology

[0002] Manganese sulfate is an important intermediate product for the production of electrolytic manganese, manganese oxides, and lithium battery cathode materials. It is widely used in industries such as new energy, pharmaceuticals, and catalysts. Among these, electrolysis of manganese sulfate solution is the mainstream method for producing manganese and manganese oxides, and its production scale in my country is enormous.

[0003] Currently, most manganese sulfate production in my country uses rhodochrosite or pyrolusite as raw materials. The process involves leaching, direct wet reduction leaching, or pyrometallurgical reduction to obtain a manganese sulfate solution, which removes iron and heavy metals. Finally, the solution is concentrated and crystallized to obtain the manganese sulfate product. Removing iron and heavy metals from the manganese sulfate solution is an extremely important step, as it affects the impurity content in the final electrolytic product and plays a decisive role in the quality of manganese and manganese oxides.

[0004] Methods for removing heavy metals from manganese sulfate solution include manganese powder replacement, sulfide precipitation, and adsorption. Sulfide precipitation is the most widely used in industry due to its simple process and high impurity removal efficiency. However, sulfides cause serious environmental pollution, and they can easily introduce new impurities into the manganese sulfate solution, resulting in poor impurity removal.

[0005] To address the aforementioned technological challenges, this invention presents a green and environmentally friendly method for removing heavy metal ions from manganese sulfate solutions, which also exhibits excellent removal efficiency. Summary of the Invention

[0006] To address the aforementioned technical deficiencies, this invention presents a green and environmentally friendly method for removing heavy metal ions from manganese sulfate solutions, which also exhibits excellent removal efficiency.

[0007] A method for removing heavy metal ions from manganese sulfate solution includes the following steps:

[0008] S1: The complex of lignin and MnO2 includes:

[0009] Lignin was dissolved in NaOH solution, and then potassium permanganate and sodium sulfite were added. After heating and stirring, a mixed solution was obtained. The mixed solution was filtered and dried to obtain sodium lignin sulfonate. Potassium permanganate and manganese sulfate were mixed with deionized water to prepare potassium permanganate solution and manganese sulfate solution, respectively. The potassium permanganate solution was stirred first, and then manganese sulfate solution was added to obtain KMnO4 / MnSO4 solution. Sodium lignin sulfonate was added to KMnO4 / MnSO4 solution, heated and stirred, and then dried in a drying oven to obtain lignin / MnO2 composite material.

[0010] S2: The preparation of modified lignin flocculant includes:

[0011] Place the container in a low-temperature bath, add triethylamine solution, bromoethane and epichlorohydrin, stir and let stand to obtain a quaternary ammonium salt solution. Mix the lignin / MnO2 composite material and NaOH solution, adjust the pH and stir, add the quaternary ammonium salt solution, keep stirring and heat in a constant temperature water bath to obtain the modified lignin flocculant.

[0012] S3: Pretreatment of manganese sulfate solution includes:

[0013] Manganese sulfate solution was placed in a container, barium sulfide was added and the pH was controlled. After stirring, the mixture was allowed to stand to obtain a mixed solution. The mixed solution was placed in a heating box for heat preservation and then cooled to obtain a pretreated manganese sulfate solution.

[0014] S4: Treatment of manganese sulfate solution with modified lignin composite flocculant includes:

[0015] Adjust the pH of the pretreated manganese sulfate solution, then add the modified lignin flocculant, and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5-5, continue to adjust the pH and repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. After the stable manganese sulfate solution is allowed to stand, it is filtered to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

[0016] Furthermore, the compounding of lignin and MnO2 in step S1 includes the following steps:

[0017] S1.1: Take 4-5 parts by weight of lignin and place it in a container. Add 18-20 parts by weight of NaOH solution and stir until the lignin is completely dissolved. Then add 0.05-0.06 parts by weight of potassium permanganate and 3-3.5 parts by weight of sodium sulfite. Heat the container to 90-95℃ and adjust the stirring speed of the stirrer to 80-100 rpm. Stir at 90-95℃ for 5-5.5 hours to obtain a mixed solution. Filter the mixed solution and place it in an oven to dry at 50-55℃ to obtain sodium lignin sulfonate.

[0018] S1.2: Place 2-3 parts by weight of potassium permanganate in a container, add 15-20 parts by weight of deionized water, stir until the potassium permanganate dissolves to obtain a potassium permanganate solution, then take 1-2 parts by weight of manganese sulfate and mix with 12-15 parts by weight of deionized water and stir until the manganese sulfate dissolves to obtain a manganese sulfate solution. Adjust the stirring speed of the magnetic stirrer to 120-150 rpm and stir the potassium permanganate solution for 25-30 minutes. Then add the manganese sulfate solution to obtain a KMnO4 / MnSO4 solution.

[0019] S1.3: Add sodium lignosulfonate to the KMnO4 / MnSO4 solution, adjust the temperature of the magnetic stirrer to 80-85℃ and the stirring speed to 200-220rpm, stir for 6-8 hours, and then place it in a drying oven at 50-60℃ for 4-5 hours to obtain the lignosulfonate / MnO2 composite material.

[0020] Furthermore, the preparation of the modified lignin flocculant in step S2 includes the following steps:

[0021] S2.1: Place the container in a low-temperature bath at -4-5℃, add 4-5 parts by weight of triethylamine solution, 2-3 parts by weight of bromoethane and 3-4 parts by weight of epichlorohydrin, stir for 12-15 minutes and let stand for 1.5-2 hours to obtain a quaternary ammonium salt solution.

[0022] S2.2: Place the lignin / MnO2 composite material in a container, add 12-15 parts by weight of NaOH solution, adjust the pH to 10-10.5, stir for 1-2 minutes, then place the container in a constant temperature water bath and heat to 80-100℃. Continue stirring while adding quaternary ammonium salt solution and adjust the temperature to 75-80℃. Stir at 75-80℃ for 2-3 hours with a stirrer at a stirring speed of 200-250 rpm to obtain the modified lignin flocculant.

[0023] Furthermore, the pretreatment of the manganese sulfate solution in step S3 includes the following steps:

[0024] S3.1: Take 200-250mL of manganese sulfate solution and place it in a container. Add 2-3g of barium sulfide and a pH adjuster to control the pH at 5-5.5. Stir for 6-8 minutes and let it stand for 45-50 minutes to obtain a mixed solution.

[0025] S3.2: Place the mixture in a heating chamber and heat it to 85-90℃. Keep it at 85-90℃ for 1.5-2 hours. After it cools naturally to room temperature, you will get a pretreated manganese sulfate solution.

[0026] Further, step S4, treating the manganese sulfate solution with the modified lignin composite flocculant, includes the following steps:

[0027] S4.1: Add dilute ammonia to the pretreated manganese sulfate solution to adjust the pH to 6.5-7, then add 35-40 mg of modified lignin flocculant, and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5-5, continue to add dilute ammonia to adjust the pH to 6.5-7. Repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution.

[0028] S4.2: Let the stable manganese sulfate solution stand for 12-15 hours, then use a vacuum filter to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

[0029] Further, the specific operation of the low-temperature bath in step S2.1 is as follows: place the container in a mixture of water and ammonium chloride, wherein the mass ratio of ammonium chloride to water is 1:(3-3.5).

[0030] Furthermore, the concentration of the triethylamine solution in step S2.1 is 55-60%.

[0031] Further, the composition of the manganese sulfate solution in step S3.1 is: Mn 85-95 g / L, Ni 200-300 mg / L, Co 70-100 mg / L, Zn 600-800 mg / L.

[0032] Furthermore, the pH adjuster in step S3.1 is manganese carbonate or manganese.

[0033] Furthermore, the concentration of the dilute ammonia solution in step S4.1 is 9.5-10.5%.

[0034] The beneficial effects are: 1. This invention combines lignin with MnO2 and prepares the resulting lignin / MnO2 composite material into a modified lignin flocculant. While retaining the basic structure of lignin, it forms a porous structure that is conducive to the adsorption of heavy metal ions. Furthermore, the combination with MnO2 increases the hydroxyl adsorption sites of the modified lignin flocculant, further enhancing its adsorption capacity for heavy metal ions and significantly reducing the heavy ion content in the manganese sulfate solution.

[0035] 2. This invention obtains a modified lignin flocculant by preparing a quaternary ammonium salt solution and adding it during the synthesis of a lignin flocculant. Through the grafting modification of the quaternary ammonium salt, the modified lignin flocculant has a higher swelling rate and forms a uniform pore structure with large pore size and thin pore walls, exhibiting excellent adsorption potential and further improving its adsorption capacity for heavy metal ions.

[0036] 3. This invention involves repeatedly adjusting and controlling the pH of the pretreated manganese sulfate solution during the pretreatment process using a modified lignin composite flocculant, thereby adjusting the H... + The concentration of the modified lignin flocculant allows the hydroxyl adsorption sites to continuously complex heavy metal ions in the solution, thereby continuously adsorbing heavy metal ions. By changing the environment, the adsorption capacity of the modified lignin flocculant for heavy metal ions is further improved. Attached Figure Description

[0037] Figure 1 This is a flowchart illustrating a method for removing heavy metal ions from manganese sulfate solution used in an embodiment of the present invention. Detailed Implementation

[0038] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. 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.

[0039] Example 1: A method for removing heavy metal ions from manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:

[0040] S1: The complex of lignin and MnO2 includes:

[0041] S1.1: Take 4 parts by weight of lignin and place it in a container. Add 18 parts by weight of NaOH solution and stir until the lignin is completely dissolved. Then add 0.05 parts by weight of potassium permanganate and 3 parts by weight of sodium sulfite. Heat the container to 90°C and adjust the stirring speed of the stirrer to 80 rpm. Stir at 90°C for 5 hours to obtain a mixed solution. Filter the mixed solution and place it in an oven to dry at 50°C to obtain sodium lignin sulfonate.

[0042] S1.2: Place 2 parts by weight of potassium permanganate in a container, add 15 parts by weight of deionized water, and stir until the potassium permanganate dissolves to obtain a potassium permanganate solution. Then take 1 part by weight of manganese sulfate and 12 parts by weight of deionized water and mix and stir until the manganese sulfate dissolves to obtain a manganese sulfate solution. Adjust the stirring speed of the magnetic stirrer to 120 rpm and stir the potassium permanganate solution for 25 minutes. Then add the manganese sulfate solution to obtain a KMnO4 / MnSO4 solution.

[0043] S1.3: Sodium lignosulfonate was added to a KMnO4 / MnSO4 solution. The temperature of the magnetic stirrer was adjusted to 80℃ and the stirring speed was 200 rpm. The mixture was stirred for 6 hours and then placed in a drying oven at 50℃ for 4 hours to obtain a lignin / MnO2 composite material. While retaining the basic structure of lignin, a porous structure that is conducive to the adsorption of heavy metal ions was formed. Furthermore, the composite with MnO2 increased the hydroxyl adsorption sites of the modified lignin flocculant, further enhancing its adsorption capacity for heavy metal ions.

[0044] S2: The preparation of modified lignin flocculant includes:

[0045] S2.1: Place the container in a low-temperature bath at -4°C, add 4 parts by weight of 55% triethylamine solution, 2 parts by weight of bromoethane and 3 parts by weight of epichlorohydrin, stir for 12 minutes and let stand for 1.5 hours to obtain a quaternary ammonium salt solution.

[0046] S2.2: Place the lignin / MnO2 composite material in a container, add 12 parts by weight of NaOH solution, adjust the pH to 10.5, stir for 1 minute, then place the container in a constant temperature water bath and heat to 80℃. Continue stirring while adding quaternary ammonium salt solution and adjust the temperature to 75℃. Stir at 200 rpm for 2 hours at 75℃ to obtain the modified lignin flocculant. Through quaternary ammonium salt grafting modification, the modified lignin flocculant has a higher swelling rate and forms a uniform pore structure with large pore size and thin pore walls, exhibiting excellent adsorption potential and further improving the adsorption capacity for heavy metal ions.

[0047] S3: Pretreatment of manganese sulfate solution includes:

[0048] S3.1: Take 200 mL of manganese sulfate solution and place it in a container. Add 2 g of barium sulfide and manganese. Control the pH at 5. Stir for 6 minutes and let stand for 45 minutes to obtain a mixed solution.

[0049] S3.2: Place the mixture in a heating chamber and heat it to 85°C. Keep it at 85°C for 1.5 hours. After it cools naturally to room temperature, you will get a pretreated manganese sulfate solution.

[0050] S4: Treatment of manganese sulfate solution with modified lignin composite flocculant includes:

[0051] S4.1: Add 9.5% dilute ammonia to the pretreated manganese sulfate solution to adjust the pH to 6.5. Then add 35 mg of modified lignin flocculant and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5, continue to add dilute ammonia to adjust the pH to 6.5. Repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. Strictly control the pH of the pretreated manganese sulfate solution and adjust the pH accordingly. + The concentration of the modified lignin flocculant allows the hydroxyl adsorption sites to continuously complex heavy metal ions in the solution, thereby continuously adsorbing heavy metal ions. By changing the environment, the adsorption performance of the modified lignin flocculant on heavy metal ions is further improved.

[0052] S4.2: Let the stable manganese sulfate solution stand for 12 hours, then use a vacuum filter to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

[0053] Example 2: A method for removing heavy metal ions from manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:

[0054] S1: The complex of lignin and MnO2 includes:

[0055] S1.1: Take 5 parts by weight of lignin and place it in a container. Add 20 parts by weight of NaOH solution and stir until the lignin is completely dissolved. Then add 0.06 parts by weight of potassium permanganate and 3.5 parts by weight of sodium sulfite. Heat the container to 90°C and adjust the stirring speed of the stirrer to 80 rpm. Stir at 90°C for 5 hours to obtain a mixed solution. Filter the mixed solution and place it in an oven to dry at 50°C to obtain sodium lignin sulfonate.

[0056] S1.2: Place 2 parts by weight of potassium permanganate in a container, add 20 parts by weight of deionized water, and stir until the potassium permanganate dissolves to obtain a potassium permanganate solution. Then take 2 parts by weight of manganese sulfate and 15 parts by weight of deionized water and mix and stir until the manganese sulfate dissolves to obtain a manganese sulfate solution. Adjust the stirring speed of the magnetic stirrer to 120 rpm and stir the potassium permanganate solution for 25 minutes. Then add the manganese sulfate solution to obtain a KMnO4 / MnSO4 solution.

[0057] S1.3: Sodium lignosulfonate was added to a KMnO4 / MnSO4 solution. The temperature of the magnetic stirrer was adjusted to 80℃ and the stirring speed was 200 rpm. The mixture was stirred for 6 hours and then placed in a drying oven at 50℃ for 4 hours to obtain a lignin / MnO2 composite material. While retaining the basic structure of lignin, a porous structure that is conducive to the adsorption of heavy metal ions was formed. Furthermore, the composite with MnO2 increased the hydroxyl adsorption sites of the modified lignin flocculant, further enhancing its adsorption capacity for heavy metal ions.

[0058] S2: The preparation of modified lignin flocculant includes:

[0059] S2.1: Place the container in a low-temperature bath at -4°C, add 5 parts by weight of 55% triethylamine solution, 3 parts by weight of bromoethane and 4 parts by weight of epichlorohydrin, stir for 12 minutes and let stand for 1.5 hours to obtain a quaternary ammonium salt solution.

[0060] S2.2: Place the lignin / MnO2 composite material in a container, add 15 parts by weight of NaOH solution, adjust the pH to 10.5, stir for 1 minute, then place the container in a constant temperature water bath and heat to 80℃. Continue stirring while adding quaternary ammonium salt solution and adjust the temperature to 75℃. Stir at 200 rpm for 2 hours at 75℃ to obtain the modified lignin flocculant. Through quaternary ammonium salt grafting modification, the modified lignin flocculant has a higher swelling rate and forms a uniform pore structure with large pore size and thin pore walls, exhibiting excellent adsorption potential and further improving the adsorption capacity for heavy metal ions.

[0061] S3: Pretreatment of manganese sulfate solution includes:

[0062] S3.1: Take 250 mL of manganese sulfate solution and place it in a container. Add 3 g of barium sulfide and manganese. Control the pH at 5. Stir for 6 minutes and let stand for 45 minutes to obtain a mixed solution.

[0063] S3.2: Place the mixture in a heating chamber and heat it to 85°C. Keep it at 85°C for 1.5 hours. After it cools naturally to room temperature, you will get a pretreated manganese sulfate solution.

[0064] S4: Treatment of manganese sulfate solution with modified lignin composite flocculant includes:

[0065] S4.1: Add 10.5% dilute ammonia to the pretreated manganese sulfate solution to adjust the pH to 6.5. Then add 40 mg of modified lignin flocculant and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5, continue to add dilute ammonia to adjust the pH to 6.5. Repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. Strictly control the pH of the pretreated manganese sulfate solution and adjust the pH accordingly. + The concentration of the modified lignin flocculant allows the hydroxyl adsorption sites to continuously complex heavy metal ions in the solution, thereby continuously adsorbing heavy metal ions. By changing the environment, the adsorption performance of the modified lignin flocculant on heavy metal ions is further improved.

[0066] S4.2: Let the stable manganese sulfate solution stand for 12 hours, then use a vacuum filter to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

[0067] Example 3: A method for removing heavy metal ions from manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:

[0068] S1: The complex of lignin and MnO2 includes:

[0069] S1.1: Take 4 parts by weight of lignin and place it in a container. Add 18 parts by weight of NaOH solution and stir until the lignin is completely dissolved. Then add 0.05 parts by weight of potassium permanganate and 3 parts by weight of sodium sulfite. Heat the container to 95°C and adjust the stirring speed of the stirrer to 100 rpm. Stir at 95°C for 5.5 hours to obtain a mixed solution. Filter the mixed solution and place it in an oven to dry at 50°C to obtain sodium lignin sulfonate.

[0070] S1.2: Place 2 parts by weight of potassium permanganate in a container, add 15 parts by weight of deionized water, and stir until the potassium permanganate dissolves to obtain a potassium permanganate solution. Then take 1 part by weight of manganese sulfate and 12 parts by weight of deionized water and mix and stir until the manganese sulfate dissolves to obtain a manganese sulfate solution. Adjust the stirring speed of the magnetic stirrer to 150 rpm and stir the potassium permanganate solution for 30 minutes. Then add the manganese sulfate solution to obtain a KMnO4 / MnSO4 solution.

[0071] S1.3: Sodium lignosulfonate was added to a KMnO4 / MnSO4 solution. The temperature of the magnetic stirrer was adjusted to 85℃ and the stirring speed was 220 rpm. The mixture was stirred for 8 hours and then placed in a drying oven at 60℃ for 5 hours to obtain a lignin / MnO2 composite material. While retaining the basic structure of lignin, a porous structure that is conducive to the adsorption of heavy metal ions was formed. Furthermore, the composite with MnO2 increased the hydroxyl adsorption sites of the modified lignin flocculant, further enhancing its adsorption capacity for heavy metal ions.

[0072] S2: The preparation of modified lignin flocculant includes:

[0073] S2.1: Place the container in a low-temperature bath at -5°C, add 4 parts by weight of 55% triethylamine solution, 2 parts by weight of bromoethane and 3 parts by weight of epichlorohydrin, stir for 15 minutes and let stand for 2 hours to obtain a quaternary ammonium salt solution.

[0074] S2.2: Place the lignin / MnO2 composite material in a container, add 12 parts by weight of NaOH solution, adjust the pH to 10, stir for 2 minutes, then place the container in a constant temperature water bath and heat to 100℃. Continue stirring while adding quaternary ammonium salt solution and adjust the temperature to 80℃. Stir at 250 rpm for 3 hours at 80℃ to obtain the modified lignin flocculant. Through quaternary ammonium salt grafting modification, the modified lignin flocculant has a higher swelling rate and forms a uniform pore structure with large pore size and thin pore walls, exhibiting excellent adsorption potential and further improving the adsorption capacity for heavy metal ions.

[0075] S3: Pretreatment of manganese sulfate solution includes:

[0076] S3.1: Take 200mL of manganese sulfate solution and place it in a container. Add 2g of barium sulfide and manganese. Control the pH at 5.5. Stir for 8 minutes and let stand for 50 minutes to obtain a mixed solution.

[0077] S3.2: Place the mixture in a heating chamber and heat it to 90°C. Keep it at 90°C for 2 hours. After it cools naturally to room temperature, you will get a pretreated manganese sulfate solution.

[0078] S4: Treatment of manganese sulfate solution with modified lignin composite flocculant includes:

[0079] S4.1: Add 9.5% dilute ammonia to the pretreated manganese sulfate solution to adjust the pH to 7. Then add 35 mg of modified lignin flocculant and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 5, continue adding dilute ammonia to adjust the pH to 7. Repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. Strictly control the pH of the pretreated manganese sulfate solution and adjust the pH accordingly. + The concentration of the modified lignin flocculant allows the hydroxyl adsorption sites to continuously complex heavy metal ions in the solution, thereby continuously adsorbing heavy metal ions. By changing the environment, the adsorption performance of the modified lignin flocculant on heavy metal ions is further improved.

[0080] S4.2: Let the stable manganese sulfate solution stand for 15 hours, then use a vacuum filter to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

[0081] Comparative Example 1: Compared with Example 1, Comparative Example 1 differs in that it uses a conventional method to remove heavy metal elements from manganese sulfate solution, specifically the barium sulfide precipitation method.

[0082] Take 10 kg of manganese sulfate and dissolve it in water to a final volume of 0.035 ml. 3 A manganese sulfate solution was obtained, and 1000 cm³ was taken. 3 The concentration of metal ions in a manganese sulfate solution was tested and analyzed using electrochemical analysis. The data were recorded, and then four 3000 cm³ aliquots were taken. 3 The manganese sulfate solution was subjected to 15-hour heavy metal ion removal operations according to Examples 1, 2, 3 and Comparative Example 1. The concentration of metal ions in the solution was then tested and analyzed by electrochemical analysis. The obtained data were recorded and tabulated with the original manganese sulfate solution data, as shown in Table 1. It can be seen that the concentration of heavy metal ions in the manganese sulfate solution after treatment in Examples 1, 2 and 3 is lower than that in Comparative Example 1, which proves that the examples have excellent removal effects on heavy metal ions.

[0083] Detector concentration Mn / g / L Co / mg / L Ni / mg / L Zn / mg / L Original manganese sulfate solution 85.63 19.45 8.6 70.3 Example 1 86.26 1.64 1.23 2.46 Example 2 87.54 1.56 1.19 2.38 Example 3 86.47 1.71 1.26 2.47 Comparative Example 1 83.63 2.13 1.81 3.63

[0084] Table 1

[0085] Comparative Example 2: Compared with Example 1, the difference of Comparative Example 2 is that the preparation process of Comparative Example 2 removes step S1 and replaces the lignin / MnO2 composite material with lignin. The remaining steps are the same as those of Example 1.

[0086] Take 3000cm 3Manganese sulfate solution was subjected to a 15-hour heavy metal ion removal process using Comparative Example 2. The obtained data were recorded and tabulated with the data measured in the Example. Then, the concentration of metal ions in the solution was tested and analyzed using electrochemical analysis. The obtained data were recorded and tabulated with the data from the Example, as shown in Table 2. It can be seen that the concentration of heavy metal ions in the manganese sulfate solution after the Example treatment was lower than that of Comparative Example 2, which proves that the combination of lignin and MnO2 can enhance the adsorption capacity of modified lignin flocculant for heavy metal ions.

[0087] Detector concentration Mn / g / L Co / mg / L Ni / mg / L Zn / mg / L Example 1 86.26 1.64 1.23 2.46 Example 2 87.54 1.56 1.19 2.38 Example 3 86.47 1.71 1.26 2.47 Comparative Example 2 83.63 5.63 3.85 10.53

[0088] Table 2

[0089] Comparative Example 3: Compared with Example 1, the difference of Comparative Example 3 is that step S2.1 is removed, while the remaining steps are the same as those of Example 1.

[0090] Take 3000cm 3 Manganese sulfate solution was subjected to a 15-hour heavy metal ion removal process using Comparative Example 3. The obtained data were recorded and tabulated with the data measured in the Example. Then, the concentration of metal ions in the solution was tested and analyzed using electrochemical analysis. The obtained data were recorded and tabulated with the data from the Example, as shown in Table 3. It can be seen that the concentration of heavy metal ions in the manganese sulfate solution after the Example treatment was lower than that of Comparative Example 3, which proves that the lignin flocculant modified by quaternary ammonium salt can enhance the adsorption capacity of the modified lignin flocculant for heavy metal ions.

[0091] Detector concentration Mn / g / L Co / mg / L Ni / mg / L Zn / mg / L Example 1 86.26 1.64 1.23 2.46 Example 2 87.54 1.56 1.19 2.38 Example 3 86.47 1.71 1.26 2.47 Comparative Example 3 83.63 2.21 1.76 4.23

[0092] Table 3

[0093] Comparative Example 4: Compared with Example 1, the difference of Comparative Example 4 is that the pH adjustment in step S4.1 was removed in Comparative Example 4, while the other steps are the same as those in Example 1.

[0094] Take 3000cm 3 Manganese sulfate solution was subjected to a 15-hour heavy metal ion removal process using Comparative Example 4. The obtained data were recorded and tabulated with the data measured in the Example. Then, the concentration of metal ions in the solution was tested and analyzed using electrochemical analysis. The obtained data were recorded and tabulated with the data from the Example, as shown in Table 4. It can be seen that the concentration of heavy metal ions in the manganese sulfate solution after the Example treatment was lower than that of Comparative Example 4. This proves that by repeatedly adjusting the pH of the pretreated manganese sulfate solution during the pretreatment process with modified lignin composite flocculant, the adsorption capacity of the modified lignin flocculant for heavy metal ions can be improved.

[0095] Detector concentration Mn / g / L Co / mg / L Ni / mg / L Zn / mg / L Example 1 86.26 1.64 1.23 2.46 Example 2 87.54 1.56 1.19 2.38 Example 3 86.47 1.71 1.26 2.47 Comparative Example 4 83.63 2.16 1.52 2.98

[0096] Table 4

[0097] The above embodiments are merely illustrative of the principles and effects of the present invention and are not intended to limit the invention. Any person skilled in the art can modify or alter the above embodiments without departing from the spirit and scope of the present invention. Therefore, all equivalent modifications or alterations made by those skilled in the art without departing from the spirit and technical concept disclosed in the present invention should still be covered by the claims of the present invention.

Claims

1. A method for removing heavy metal ions from manganese sulfate solution, characterized in that, Includes the following steps: S1: The complex of lignin and MnO2 includes: Lignin was dissolved in NaOH solution, and then potassium permanganate and sodium sulfite were added. After heating and stirring, a mixed solution was obtained. The mixed solution was filtered and dried to obtain sodium lignin sulfonate. Potassium permanganate and manganese sulfate were mixed with deionized water to prepare potassium permanganate solution and manganese sulfate solution, respectively. The potassium permanganate solution was stirred first, and then manganese sulfate solution was added to obtain KMnO4 / MnSO4 solution. Sodium lignin sulfonate was added to KMnO4 / MnSO4 solution, heated and stirred, and then dried in a drying oven to obtain lignin / MnO2 composite material. S2: The preparation of modified lignin flocculant includes: Place the container in a low-temperature bath, add triethylamine solution, bromoethane and epichlorohydrin, stir and let stand to obtain a quaternary ammonium salt solution. Mix the lignin / MnO2 composite material and NaOH solution, adjust the pH and stir, add the quaternary ammonium salt solution, keep stirring and heat in a constant temperature water bath to obtain the modified lignin flocculant. S3: Pretreatment of manganese sulfate solution includes: Manganese sulfate solution was placed in a container, barium sulfide was added and the pH was controlled. After stirring, the mixture was allowed to stand to obtain a mixed solution. The mixed solution was placed in a heating box for heat preservation and then cooled to obtain a pretreated manganese sulfate solution. S4: Treatment of manganese sulfate solution with modified lignin composite flocculant includes: Adjust the pH of the pretreated manganese sulfate solution, then add the modified lignin flocculant, and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5-5, continue to adjust the pH and repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. After the stable manganese sulfate solution is allowed to stand, it is filtered to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

2. The method for removing heavy metal ions from manganese sulfate solution according to claim 1, characterized in that, Step S1, the compounding of lignin and MnO2, includes the following steps: S1.1: Take 4-5 parts by weight of lignin and place it in a container. Add 18-20 parts by weight of NaOH solution and stir until the lignin is completely dissolved. Then add 0.05-0.06 parts by weight of potassium permanganate and 3-3.5 parts by weight of sodium sulfite. Heat the container to 90-95℃ and adjust the stirring speed of the stirrer to 80-100 rpm. Stir at 90-95℃ for 5-5.5 hours to obtain a mixed solution. Filter the mixed solution and place it in an oven to dry at 50-55℃ to obtain sodium lignin sulfonate. S1.2: Place 2-3 parts by weight of potassium permanganate in a container, add 15-20 parts by weight of deionized water, stir until the potassium permanganate dissolves to obtain a potassium permanganate solution, then take 1-2 parts by weight of manganese sulfate and mix with 12-15 parts by weight of deionized water and stir until the manganese sulfate dissolves to obtain a manganese sulfate solution. Adjust the stirring speed of the magnetic stirrer to 120-150 rpm and stir the potassium permanganate solution for 25-30 minutes. Then add the manganese sulfate solution to obtain a KMnO4 / MnSO4 solution. S1.3: Add sodium lignosulfonate to the KMnO4 / MnSO4 solution, adjust the temperature of the magnetic stirrer to 80-85℃ and the stirring speed to 200-220rpm, stir for 6-8 hours, and then place it in a drying oven at 50-60℃ for 4-5 hours to obtain the lignosulfonate / MnO2 composite material.

3. The method for removing heavy metal ions from manganese sulfate solution according to claim 2, characterized in that, The preparation of the modified lignin flocculant in step S2 includes the following steps: S2.1: Place the container in a low-temperature bath at -4-5℃, add 4-5 parts by weight of triethylamine solution, 2-3 parts by weight of bromoethane and 3-4 parts by weight of epichlorohydrin, stir for 12-15 minutes and let stand for 1.5-2 hours to obtain a quaternary ammonium salt solution. S2.2: Place the lignin / MnO2 composite material in a container, add 12-15 parts by weight of NaOH solution, adjust the pH to 10-10.5, stir for 1-2 minutes, then place the container in a constant temperature water bath and heat to 80-100℃. Continue stirring while adding quaternary ammonium salt solution and adjust the temperature to 75-80℃. Stir at 75-80℃ for 2-3 hours with a stirrer at a stirring speed of 200-250 rpm to obtain the modified lignin flocculant.

4. The method for removing heavy metal ions from manganese sulfate solution according to claim 3, characterized in that, Step S3, the pretreatment of the manganese sulfate solution, includes the following steps: S3.1: Take 200-250mL of manganese sulfate solution and place it in a container. Add 2-3g of barium sulfide and a pH adjuster to control the pH at 5-5.

5. Stir for 6-8 minutes and let it stand for 45-50 minutes to obtain a mixed solution. S3.2: Place the mixture in a heating chamber and heat it to 85-90℃. Keep it at 85-90℃ for 1.5-2 hours. After it cools naturally to room temperature, you will get a pretreated manganese sulfate solution.

5. The method for removing heavy metal ions from manganese sulfate solution according to claim 4, characterized in that, Step S4, treating manganese sulfate solution with modified lignin composite flocculant, includes the following steps: S4.1: Add dilute ammonia to the pretreated manganese sulfate solution to adjust the pH to 6.5-7, then add 35-40 mg of modified lignin flocculant, and measure the pH of the pretreated manganese sulfate solution in real time. When the pH of the pretreated manganese sulfate solution drops to 4.5-5, continue to add dilute ammonia to adjust the pH to 6.5-7. Repeat the operation until the pH of the pretreated manganese sulfate solution is maintained at around 7 to obtain a stable manganese sulfate solution. S4.2: Let the stable manganese sulfate solution stand for 12-15 hours, then use a vacuum filter to separate the solid and liquid and collect the liquid to obtain a purified manganese sulfate solution.

6. The method for removing heavy metal ions from manganese sulfate solution according to claim 3, characterized in that, The specific operation of the low-temperature bath in step S2.1 is as follows: place the container in a mixture of water and ammonium chloride, wherein the mass ratio of ammonium chloride to water is 1:(3-3.5).

7. The method for removing heavy metal ions from manganese sulfate solution according to claim 3, characterized in that, In step S2.1, the concentration of the triethylamine solution is 55-60%.

8. The method for removing heavy metal ions from manganese sulfate solution according to claim 4, characterized in that, The composition of the manganese sulfate solution in step S3.1 is: Mn 95-98 g / L, Ni 200-300 mg / L, Co 70-100 mg / L, Zn 600-800 mg / L.

9. The method for removing heavy metal ions from manganese sulfate solution according to claim 4, characterized in that, In step S3.1, the pH adjuster is manganese carbonate or manganese.

10. The method for removing heavy metal ions from manganese sulfate solution according to claim 5, characterized in that, In step S4.1, the concentration of dilute ammonia is 9.5%-10.5%.

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