Method for deep purification of manganese sulfate solution for electrolytic manganese dioxide
By combining lignin-based iron-manganese-doped carbon adsorbents with sodium lignin sulfonate, the problem of reduced manganese content in existing technologies has been solved, enabling deep purification of manganese sulfate solution and the production of high-purity manganese dioxide.
Patent Information
- Authority / Receiving Office
- CN · China
- Patent Type
- Patents(China)
- Current Assignee / Owner
- GUANGXI NON FERROUS METALS GROUP HUIYUANMENGYE
- Filing Date
- 2024-02-28
- Publication Date
- 2026-06-05
AI Technical Summary
Existing SDD chelating agents cannot selectively precipitate heavy metal ions when removing them from manganese sulfate solutions, resulting in a decrease in manganese content and affecting the yield of electrolytic manganese dioxide.
Iron-manganese-doped carbon adsorbent was prepared by lignin through high-temperature pyrolysis. The adsorbent was then combined with sodium lignin sulfonate to adsorb and complex heavy metal ions in manganese sulfate solution. The iron-manganese-doped carbon adsorbent improved its adsorption capacity in high-concentration manganese ion electrolyte, and iron replenished the manganese ion loss. The filter residue was treated with high-temperature pyrolysis to prepare alkali lignin as a byproduct.
This improved the purity of the manganese sulfate solution, ensured the yield of manganese dioxide, reduced costs, and achieved effective removal of heavy metal ions.
Smart Images
Figure CN118026271B_ABST
Abstract
Description
Technical Field
[0001] This invention relates to the field of manganese dioxide preparation technology, and specifically to a method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution. Background Technology
[0002] Electrolytic manganese dioxide is generally produced from high-grade manganese ore. Based on the reaction raw materials, the main processes include the manganese carbonate ore method, the manganese oxide reduction roasting method, and the "two-ore" method. The "two-ore" method requires the reduction leaching, purification, and electrolysis of manganese dioxide ore and pyrite to obtain a manganese sulfate solution. During the leaching process, other heavy metal ions from the manganese dioxide and pyrite, such as copper, nickel, and zinc, also dissolve in the manganese sulfate solution in their metal ion form. To prepare high-purity electrolytic manganese dioxide, these heavy metal ions need to be removed from the manganese sulfate solution for purification.
[0003] Existing methods for removing heavy metal ions from manganese sulfate solutions mainly include adsorption. This involves using chemical reagents to adsorb heavy metal ions from the manganese sulfate solution onto an adsorbent, where they complex with the adsorbent to form insoluble compounds, which are then removed by filtration. SDD chelating agents, commonly used for precipitating heavy metals in wastewater, are frequently employed. These chelating agents have a wide range of heavy metal ion adsorption capabilities. However, SDD chelating agents cannot selectively precipitate heavy metal ions, thus also complexing and precipitating manganese from the manganese sulfate solution, leading to a decrease in manganese content and a reduction in manganese dioxide production.
[0004] Therefore, we provide a method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, which solves the problem of reduced manganese dioxide yield caused by SDD chelating agent complexing manganese ions while removing heavy metal ions from the complexed manganese sulfate. Summary of the Invention
[0005] To address the shortcomings of existing technologies, the present invention aims to provide a method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution.
[0006] A method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution includes the following steps:
[0007] S1: Preliminary treatment of crude manganese sulfate solution
[0008] NaOH solution was added to the crude manganese sulfate solution obtained by leaching manganese dioxide ore and pyrite with sulfuric acid until the pH of the crude manganese sulfate solution was adjusted to neutral. The solution was then filtered to remove solids and the treated manganese sulfate solution was obtained.
[0009] S2: Preparation of iron-manganese-doped carbon adsorbent via lignin
[0010] Manganese ferrite was prepared by adding FeCl3 and MnCl2 to the reaction chamber. Lignin was dissolved in deionized water, heated, and magnetically stirred. Then, NaHCO3 aqueous solution was added and magnetically stirred to mix evenly to obtain intermediate I. Manganese ferrite was added to intermediate I and reacted fully by magnetic stirring. The precipitate was dried to obtain intermediate II. Intermediate II was placed in a tube furnace and pyrolyzed under a nitrogen atmosphere. After washing and drying, iron-manganese-doped carbon adsorbent was obtained.
[0011] S3: Treatment of heavy metal ions in manganese sulfate solution by complexation and precipitation using sodium lignosulfonate and iron-manganese-doped carbon adsorbent.
[0012] Add the treated manganese sulfate solution obtained in step S1 to a constant temperature magnetic stirrer, then add iron-manganese doped carbon adsorbent and sodium lignosulfonate to the constant temperature magnetic stirrer, and adjust the pH to acidic by adding dilute sulfuric acid. After magnetic stirring, filter to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
[0013] S4: Preparation of byproducts from filter residue in high-temperature pyrolysis step S3
[0014] The filter residue from step S3 is dissolved in NaOH solution to obtain a suspension. The suspension is heated and dried in an electric furnace, then ground. All the powder obtained from the grinding is placed in a tube furnace and heat-treated under a nitrogen atmosphere to obtain heat-treated powder. The heat-treated powder is dissolved in water and acid is added, then filtered. The solid material obtained from the filtration is washed with water and dried to obtain alkali lignin byproduct.
[0015] Further, step S2 involves preparing an iron-manganese-doped carbon adsorbent using lignin, comprising the following steps:
[0016] S2.1: Add FeCl3 and MnCl2 to the reaction tank respectively, then add 10-15 parts by volume of deionized water and 20-25 parts by volume of polyethylene glycol to the reaction tank, and dissolve and mix by mechanical stirring for 30-35 minutes, and adjust the pH of the solution in the reaction tank to 10-11 with 1 mol / L NaOH;
[0017] S2.2: Next, stir the solution in the reaction chamber at a speed of 400-450 rpm for 30-35 min, then heat the reaction chamber to 180-200℃ and maintain the temperature for 20-24 h. Then let it stand and cool to room temperature. Use a magnet to separate the material in the reaction chamber from the supernatant to obtain magnetic material. Wash it three times with ultrapure water, dry it in an oven at 60-80℃ for 20-24 h, grind it through a 300-mesh sieve to obtain manganese ferrite.
[0018] S2.3: Dissolve 2-3 parts by weight of lignin in 50-55 parts by volume of deionized water, heat to 70-80℃ and stir magnetically, then add 60-80 parts by volume of 0.5-1 mol / L NaHCO3 aqueous solution, and keep stirring magnetically to mix evenly to obtain intermediate I;
[0019] S2.4: Mix 10-15 parts by volume of water and 0.2-0.4 parts by weight of manganese ferrite and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the precipitate in an oven at 60-70℃ for 20-24 hours to obtain intermediate II. Place intermediate II in a tube furnace and pyrolyze it under a nitrogen atmosphere. Then, take the material out of the tube furnace, grind it, and pass it through a 300-mesh sieve. Wash the sieved product with water and ethanol alternately three times, and dry it to obtain the iron-manganese-doped carbon adsorbent.
[0020] Further, step S3 involves the complexation and precipitation of heavy metal ions in the manganese sulfate solution using sodium lignosulfonate and iron-manganese-doped carbon adsorbents, including the following steps:
[0021] S3.1: Add the treated manganese sulfate solution obtained in step S1 to a thermostatic magnetic stirrer, then add iron-manganese-doped carbon adsorbent and sodium lignosulfonate to the thermostatic magnetic stirrer, and adjust the pH of the system in the thermostatic magnetic stirrer to 5.5-6 by adding dilute sulfuric acid.
[0022] S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 100-120 minutes at 25-30℃. Then filter the material in the thermostatic magnetic stirrer with a 0.22um filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
[0023] Furthermore, the preparation of by-products from the filter residue in step S3 via high-temperature pyrolysis in step S4 includes the following steps:
[0024] S4.1: Dissolve the filter residue from step S3 in 1 mol / L NaOH solution to obtain a suspension. Heat the suspension to boiling in an electric furnace, evaporate and dry the water, grind it, and put all the powder obtained from grinding into a tube furnace for heat treatment under a nitrogen atmosphere at a temperature of 360-440℃ for 0.5-1h to obtain heat-treated powder.
[0025] S4.2: Dissolve the heat-treated powder in water, adjust the pH to 3-6 with acid, filter, remove the liquid portion, wash the solid obtained by filtration with water until the pH is neutral, and dry to obtain alkali lignin byproduct.
[0026] Further, step S1 involves the preliminary treatment of the crude manganese sulfate solution, including the following steps:
[0027] S1.1: Mix manganese dioxide ore powder, pyrite powder and sulfuric acid, and heat the mixture with steam to 90-100℃. Leach for 4-6 hours to obtain a leachate. Then add potassium removal agent and sulfuric acid to the leachate, adjust the pH of the leachate to 1-4, and control the temperature at 50-60℃. React for 1-2 hours, and then filter to obtain crude manganese sulfate solution.
[0028] S1.2: Add 1 mol / L NaOH solution to the crude manganese sulfate solution until the pH reaches 6-7, and filter to remove solids to obtain the treated manganese sulfate solution.
[0029] Further, in step S1.1, the mass ratio of manganese dioxide ore powder, pyrite powder and sulfuric acid is 1:(0.2-0.5):(0.35-0.65).
[0030] Furthermore, in step S2.1, the molar ratio of FeCl3 to MnCl2 is 2:(1-1.5).
[0031] Furthermore, in step S2.4, the tubular furnace is heated to 700-750℃ for pyrolysis for 1.5-2 hours, with a heating rate of 3-5℃ / min.
[0032] Further, in step S3.1, the volume ratio of manganese sulfate solution, iron-manganese doped carbon adsorbent and sodium lignin sulfonate is (80-100):(1-2):(5-10).
[0033] Furthermore, the mass ratio of NaOH solution in step S4.1 to filter residue in step S3 is 1:(1.5-2).
[0034] Compared with the prior art, the present invention has at least the following beneficial effects:
[0035] 1. This invention prepares an iron-manganese-doped carbon adsorbent by high-temperature pyrolysis of lignin. The iron-manganese-doped carbon adsorbent adsorbs heavy metal ions in manganese sulfate solution. Lignin is a natural substance extracted from plants. The carbon adsorbent obtained by high-temperature treatment of lignin has a certain flocculation effect on metal ions. It can complex with heavy metal ions such as lead, cobalt, and nickel in manganese sulfate solution to form solid complexes, thereby achieving the effect of removing other heavy metal ions in manganese sulfate solution, thus improving the purity of manganese sulfate solution and laying the foundation for the preparation of high-purity manganese dioxide.
[0036] 2. This invention involves preparing an adsorbent doped with manganese ferrite and using the iron-manganese-doped carbon adsorbent to adsorb heavy metal ions from a manganese sulfate solution. Since ferrous ions are less likely to complex with the adsorbent than manganese ions in a high-concentration manganese ion electrolyte, a small portion of the manganese ions in the solution are complexed into a solid, reducing the purity of the manganese sulfate solution. Therefore, manganese ferrite is added to the adsorbent. The addition of iron enhances the adsorption capacity of the iron-manganese-doped carbon adsorbent, while manganese is dissolved in trace amounts in the manganese sulfate solution during the complexation of heavy metal ions by the iron-manganese-doped carbon adsorbent, thus replenishing the manganese ions that are complexed in the solution.
[0037] 3. This invention utilizes high-temperature pyrolysis to process the filter residue obtained after adsorbing manganese sulfate solution with an iron-manganese-doped carbon adsorbent. The filter residue mainly consists of complexes of heavy metal ions, sodium lignin sulfonate, and the iron-manganese-doped carbon adsorbent. High-temperature pyrolysis decomposes the sodium lignin sulfonate into the byproduct alkali lignin, while the heavy metals are separated from the solid alkali lignin by acid leaching. This ensures that the byproduct alkali lignin does not carry excessive heavy metal ions, allowing for secondary utilization and thus bringing certain economic benefits and saving costs. Attached Figure Description
[0038] The accompanying drawings, which are incorporated herein and form part of the specification, illustrate embodiments of the present disclosure and, together with the specification, further serve to explain the principles of the present disclosure and enable those skilled in the art to implement and use the present disclosure.
[0039] Figure 1 This is a flowchart illustrating a method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, as used in an embodiment of the present invention.
[0040] Figure 2 This is a table showing the chemical multi-element results of the treatment of manganese sulfate solution according to the present invention.
[0041] Figure 3 The table shows the manganese content of Comparative Examples 1 and 2 and the embodiments of the present invention. Detailed Implementation
[0042] The following describes in detail a method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, provided by the present invention, with reference to the accompanying drawings and specific embodiments. It should be noted that, to make the embodiments more detailed, the following embodiments are the best and preferred embodiments; those skilled in the art can also use other alternative methods to implement some known technologies; and the accompanying drawings are only for more specific description of the embodiments and are not intended to specifically limit the present invention.
[0043] Example 1:
[0044] A method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:
[0045] S1: Preliminary treatment of crude manganese sulfate solution
[0046] S1.1: Manganese dioxide ore powder, pyrite powder and sulfuric acid are mixed in a mass ratio of 1:0.2:0.35. The mixture is heated to 90°C with steam and leached for 6 hours to obtain a leachate. Potassium removal agent and sulfuric acid are then added to the leachate to adjust the pH of the leachate to 2. The temperature is controlled at 60°C and the reaction is carried out for 1 hour. The mixture is then filtered to obtain crude manganese sulfate solution.
[0047] S1.2: Add 1 mol / L NaOH solution to the crude manganese sulfate solution until the pH reaches 7, and filter to remove solids to obtain the treated manganese sulfate solution.
[0048] S2: Preparation of iron-manganese-doped carbon adsorbent via lignin
[0049] S2.1: Add FeCl3 and MnCl2 to the reaction tank respectively, with a molar ratio of FeCl3 to MnCl2 of 2:1. Then add 10 parts by volume of deionized water and 20 parts by volume of polyethylene glycol to the reaction tank, and dissolve and mix them by mechanical stirring for 30 minutes. Adjust the pH of the solution in the reaction tank to 11 with 1 mol / L NaOH.
[0050] S2.2: Next, the solution in the reaction chamber was stirred at 400 rpm for 30 min. Then the reaction chamber was heated to 200℃ and the temperature was maintained for 24 h. After that, it was allowed to cool to room temperature. The magnetic material in the reaction chamber was separated from the supernatant by a magnet to obtain magnetic material. It was washed three times with ultrapure water, dried in an oven at 60℃ for 24 h, and ground through a 300-mesh sieve to obtain manganese ferrite.
[0051] S2.3: Dissolve 2 parts by weight of lignin in 50 parts by volume of deionized water, heat to 80°C and stir magnetically, then add 80 parts by volume of 1 mol / L NaHCO3 aqueous solution and keep stirring magnetically to mix evenly to obtain intermediate I.
[0052] S2.4: Mix 10 parts by volume of water and 0.2 parts by weight of manganese ferrite and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the resulting precipitate in an oven at 60°C for 24 hours to obtain intermediate II. Place intermediate II in a tube furnace and pyrolyze it under a nitrogen atmosphere. The pyrolysis parameters are as follows: heat the tube furnace to 700°C and pyrolyze for 2 hours at a heating rate of 5°C / min. Then, take the material out of the tube furnace, grind it, and pass it through a 300-mesh sieve. Wash the sieved product with water and ethanol alternately 3 times, and dry it to obtain the iron-manganese-doped carbon adsorbent.
[0053] S3: Heavy metal ions in manganese sulfate solution are treated by complexing and precipitating using sodium lignosulfonate and iron-manganese-doped carbon adsorbent.
[0054] S3.1: Add the treated manganese sulfate solution obtained in step S1 to a thermostatic magnetic stirrer, and then add iron-manganese doped carbon adsorbent and sodium lignosulfonate to the thermostatic magnetic stirrer. The volume ratio of manganese sulfate solution, iron-manganese doped carbon adsorbent and sodium lignosulfonate is 100:2:5. The pH of the system in the thermostatic magnetic stirrer is adjusted to 6 by adding dilute sulfuric acid.
[0055] S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 120 minutes at 25℃. Then filter the material in the thermostatic magnetic stirrer with a 0.22um filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
[0056] S4: Preparation of byproducts from filter residue in high-temperature pyrolysis step S3
[0057] S4.1: Dissolve the filter residue from step S3 in 1 mol / L NaOH solution. The mass ratio of NaOH solution to filter residue from step S3 is 1:2 to obtain a suspension. Heat the suspension to boiling in an electric furnace to evaporate and dry the water. Grind the powder and put all the powder obtained into a tube furnace for heat treatment in a nitrogen atmosphere at a temperature of 440℃ for 1 hour to obtain heat-treated powder.
[0058] S4.2: Dissolve the heat-treated powder in water, adjust the pH to 3 with acid, filter, remove the liquid portion, wash the solid obtained by filtration with water until the pH is neutral, and dry to obtain alkali lignin byproduct.
[0059] Example 2:
[0060] A method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:
[0061] S1: Preliminary treatment of crude manganese sulfate solution
[0062] S1.1: Manganese dioxide ore powder, pyrite powder and sulfuric acid are mixed in a mass ratio of 1:0.5:0.65. The mixture is heated to 90°C with steam and leached for 6 hours to obtain a leachate. Potassium removal agent and sulfuric acid are then added to the leachate to adjust the pH of the leachate to 2. The temperature is controlled at 60°C and the reaction is carried out for 1 hour. The mixture is then filtered to obtain crude manganese sulfate solution.
[0063] S1.2: Add 1 mol / L NaOH solution to the crude manganese sulfate solution until the pH reaches 7, and filter to remove solids to obtain the treated manganese sulfate solution.
[0064] S2: Preparation of iron-manganese-doped carbon adsorbent via lignin
[0065] S2.1: Add FeCl3 and MnCl2 to the reaction tank respectively, with a molar ratio of FeCl3 to MnCl2 of 2:1.5. Then add 10 parts by volume of deionized water and 20 parts by volume of polyethylene glycol to the reaction tank, and dissolve and mix them by mechanical stirring for 30 min. Adjust the pH of the solution in the reaction tank to 11 with 1 mol / L NaOH.
[0066] S2.2: Next, the solution in the reaction chamber was stirred at 400 rpm for 30 min. Then the reaction chamber was heated to 200℃ and the temperature was maintained for 24 h. After that, it was allowed to cool to room temperature. The magnetic material in the reaction chamber was separated from the supernatant by a magnet to obtain magnetic material. It was washed three times with ultrapure water, dried in an oven at 60℃ for 24 h, and ground through a 300-mesh sieve to obtain manganese ferrite.
[0067] S2.3: Dissolve 2 parts by weight of lignin in 50 parts by volume of deionized water, heat to 80°C and stir magnetically, then add 60 parts by volume of 1 mol / L NaHCO3 aqueous solution and keep stirring magnetically to mix evenly to obtain intermediate I;
[0068] S2.4: Mix 15 parts by volume of water and 0.4 parts by weight of manganese ferrite and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the resulting precipitate in an oven at 60°C for 24 hours to obtain intermediate II. Place intermediate II in a tube furnace and pyrolyze it under a nitrogen atmosphere. The pyrolysis parameters are as follows: heat the tube furnace to 700°C and pyrolyze for 2 hours at a heating rate of 5°C / min. Then, take the material out of the tube furnace, grind it, and pass it through a 300-mesh sieve. Wash the sieved product with water and ethanol alternately three times, and dry it to obtain the iron-manganese-doped carbon adsorbent.
[0069] S3: Heavy metal ions in manganese sulfate solution are treated by complexing and precipitating using sodium lignosulfonate and iron-manganese-doped carbon adsorbent.
[0070] S3.1: Add the treated manganese sulfate solution obtained in step S1 to a thermostatic magnetic stirrer, and then add iron-manganese doped carbon adsorbent and sodium lignosulfonate to the thermostatic magnetic stirrer. The volume ratio of manganese sulfate solution, iron-manganese doped carbon adsorbent and sodium lignosulfonate is 80:1:10. The pH of the system in the thermostatic magnetic stirrer is adjusted to 6 by adding dilute sulfuric acid.
[0071] S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 120 minutes at 25℃. Then filter the material in the thermostatic magnetic stirrer with a 0.22um filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
[0072] S4: Preparation of byproducts from filter residue in high-temperature pyrolysis step S3
[0073] S4.1: Dissolve the filter residue from step S3 in 1 mol / L NaOH solution. The mass ratio of NaOH solution to filter residue from step S3 is 1:1.5 to obtain a suspension. Heat the suspension to boiling in an electric furnace to evaporate and dry the water. Grind the powder and put all the powder obtained into a tube furnace for heat treatment in a nitrogen atmosphere at a temperature of 440℃ for 1 hour to obtain heat-treated powder.
[0074] S4.2: Dissolve the heat-treated powder in water, adjust the pH to 3 with acid, filter, remove the liquid portion, wash the solid obtained by filtration with water until the pH is neutral, and dry to obtain alkali lignin byproduct.
[0075] Example 3:
[0076] A method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, such as... Figure 1 As shown, it includes the following steps:
[0077] S1: Preliminary treatment of crude manganese sulfate solution
[0078] S1.1: Manganese dioxide ore powder, pyrite powder and sulfuric acid are mixed in a mass ratio of 1:0.2:0.35. The mixture is heated to 90°C with steam and leached for 6 hours to obtain a leachate. Potassium removal agent and sulfuric acid are then added to the leachate to adjust the pH of the leachate to 4. The temperature is controlled at 50°C and the reaction is carried out for 2 hours. The mixture is then filtered to obtain crude manganese sulfate solution.
[0079] S1.2: Add 1 mol / L NaOH solution to the crude manganese sulfate solution until the pH reaches 6, and filter to remove solids to obtain the treated manganese sulfate solution.
[0080] S2: Preparation of iron-manganese-doped carbon adsorbent via lignin
[0081] S2.1: Add FeCl3 and MnCl2 to the reaction tank respectively, with a molar ratio of FeCl3 to MnCl2 of 2:1. Then add 10 parts by volume of deionized water and 20 parts by volume of polyethylene glycol to the reaction tank, and dissolve and mix them by mechanical stirring for 30 minutes. Adjust the pH of the solution in the reaction tank to 10 with 1 mol / L NaOH.
[0082] S2.2: Next, the solution in the reaction chamber was stirred at 400 rpm for 30 min. Then the reaction chamber was heated to 180°C and the temperature was maintained for 20 h. After that, it was allowed to cool to room temperature. The magnetic material in the reaction chamber was separated from the supernatant by a magnet to obtain magnetic material. It was washed three times with ultrapure water, dried in an oven at 60°C for 24 h, and ground through a 300-mesh sieve to obtain manganese ferrite.
[0083] S2.3: Dissolve 2 parts by weight of lignin in 50 parts by volume of deionized water, heat to 80°C and stir magnetically, then add 80 parts by volume of 1 mol / L NaHCO3 aqueous solution and keep stirring magnetically to mix evenly to obtain intermediate I.
[0084] S2.4: Mix 10 parts by volume of water and 0.2 parts by weight of manganese ferrite and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the resulting precipitate in an oven at 60℃ for 24 hours to obtain intermediate II. Place intermediate II in a tube furnace and pyrolyze it under a nitrogen atmosphere. The pyrolysis parameters are as follows: heat the tube furnace to 750℃ and pyrolyze for 1.5 hours at a heating rate of 3℃ / min. Then, take the material out of the tube furnace, grind it, and pass it through a 300-mesh sieve. Wash the sieved product with water and ethanol alternately three times, and dry it to obtain the iron-manganese-doped carbon adsorbent.
[0085] S3: Heavy metal ions in manganese sulfate solution are treated by complexing and precipitating using sodium lignosulfonate and iron-manganese-doped carbon adsorbent.
[0086] S3.1: Add the treated manganese sulfate solution obtained in step S1 to a thermostatic magnetic stirrer, and then add iron-manganese doped carbon adsorbent and sodium lignosulfonate to the thermostatic magnetic stirrer. The volume ratio of manganese sulfate solution, iron-manganese doped carbon adsorbent and sodium lignosulfonate is 100:2:5. The pH of the system in the thermostatic magnetic stirrer is adjusted to 5.5 by adding dilute sulfuric acid.
[0087] S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 120 minutes at 30℃. Then filter the material in the thermostatic magnetic stirrer with a 0.22um filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
[0088] S4: Preparation of byproducts from filter residue in high-temperature pyrolysis step S3
[0089] S4.1: Dissolve the filter residue from step S3 in 1 mol / L NaOH solution. The mass ratio of NaOH solution to filter residue in step S3 is 1:2 to obtain a suspension. Heat the suspension to boiling in an electric furnace, evaporate and dry the water, grind, and put all the powder obtained from grinding into a tube furnace for heat treatment under a nitrogen atmosphere at a temperature of 360℃ for 0.5 h to obtain heat-treated powder.
[0090] S4.2: Dissolve the heat-treated powder in water, adjust the pH to 6 with acid, filter, remove the liquid portion, wash the solid obtained by filtration with water until the pH is neutral, and dry to obtain alkali lignin byproduct.
[0091] Comparative Example 1:
[0092] Compared with Example 1, the difference of Comparative Example 1 is that step S2, which involves the preparation of iron-manganese-doped carbon adsorbent, is not performed. In step S3, only sodium lignosulfonate is added, while the other steps remain unchanged. Specifically, S3.1: The treated manganese sulfate solution obtained in step S1 is added to a thermostatic magnetic stirrer, and then sodium lignosulfonate is added to the thermostatic magnetic stirrer. The volume ratio of manganese sulfate solution to sodium lignosulfonate is 100:5. The pH of the system in the thermostatic magnetic stirrer is adjusted to 6 by adding dilute sulfuric acid.
[0093] S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 120 min at 25℃. Then filter the material in the thermostatic magnetic stirrer through a 0.22 μm filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed. The obtained manganese sulfate solution with heavy metal ions removed is designated as Comparative Example 1.
[0094] Comparative Example 2:
[0095] Compared with Example 1, Comparative Example 2 differs in that steps S2.1 and S2.2 are omitted in step S2, and manganese ferrite is replaced with FeCl3 in step S2.4. The remaining steps remain unchanged. Specifically:
[0096] S2.3: Dissolve 2 parts by weight of lignin in 50 parts by volume of deionized water, heat to 80°C and stir magnetically, then add 80 parts by volume of 1 mol / L NaHCO3 aqueous solution and keep stirring magnetically to mix evenly to obtain intermediate I.
[0097] S2.4: Mix 10 parts by volume of water and 0.2 parts by weight of FeCl3 and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the precipitate in an oven at 60°C for 24 hours to obtain intermediate II. Place intermediate II in a tube furnace and heat the tube furnace to 700°C for 2 hours at a heating rate of 5°C / min. Pyrolysis is carried out under a nitrogen atmosphere. Then, the material in the tube furnace is taken out, ground, and passed through a 300-mesh sieve. The sieved product is then washed three times with water and ethanol alternately and dried to obtain the carbon adsorbent.
[0098] In step S3, a carbon adsorbent was used to replace the iron-manganese-doped carbon adsorbent, and the resulting manganese sulfate solution with heavy metal ions removed was designated as Comparative Example 2.
[0099] The manganese sulfate solutions obtained in step S3 of Examples 1-3 after removing heavy metal ions are respectively referred to as Examples 1-3.
[0100] The heavy metal ion content in the treated manganese sulfate solutions obtained in step S1 of Examples 1-3 was determined using electrochemical analysis. Figure 2 As shown.
[0101] The manganese content in Comparative Example 1, Comparative Example 2, and Examples 1-3 was determined using an atomic absorption spectrophotometer, and the concentration of manganese sulfate was calculated. The results were then compiled into a table, as follows: Figure 3 As shown, it can be seen that Comparative Example 1, which uses sodium lignosulfonate alone, has the lowest manganese content. The manganese content of Comparative Example 2 is higher than that of Comparative Example 1 but lower than that of the Example. This is because the iron-manganese-doped carbon adsorbent has a good adsorption effect on heavy metal ions. However, when adsorbing and precipitating heavy metal ions, a small amount of manganese ions are also adsorbed and complexed, and then removed by filtration. Therefore, the manganese content is lower than that of the Example.
[0102] 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 deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution, characterized in that, Includes the following steps: S1: Preliminary treatment of crude manganese sulfate solution NaOH solution was added to the crude manganese sulfate solution obtained by leaching manganese dioxide ore and pyrite with sulfuric acid until the pH of the crude manganese sulfate solution was adjusted to neutral. The solution was then filtered to remove solids and the treated manganese sulfate solution was obtained. S2: Preparation of iron-manganese-doped carbon adsorbent via lignin Manganese ferrite was prepared by adding FeCl3 and MnCl2 to the reaction chamber. Lignin was dissolved in deionized water, heated, and magnetically stirred. Then, NaHCO3 aqueous solution was added and magnetically stirred to mix evenly to obtain intermediate I. Manganese ferrite was added to intermediate I and reacted fully by magnetic stirring. The precipitate was dried to obtain intermediate II. Intermediate II was placed in a tube furnace and pyrolyzed under a nitrogen atmosphere. After washing and drying, iron-manganese-doped carbon adsorbent was obtained. S3: Heavy metal ions in manganese sulfate solution are treated by complexing and precipitating using sodium lignosulfonate and iron-manganese-doped carbon adsorbent. Add the treated manganese sulfate solution obtained in step S1 to a constant temperature magnetic stirrer, then add iron-manganese doped carbon adsorbent and sodium lignosulfonate to the constant temperature magnetic stirrer, and adjust the pH to acidic by adding dilute sulfuric acid. After magnetic stirring, filter to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed. S4: Preparation of byproducts from filter residue in high-temperature pyrolysis step S3 The filter residue from step S3 is dissolved in NaOH solution to obtain a suspension. The suspension is heated and dried in an electric furnace, then ground. All the powder obtained from the grinding is placed in a tube furnace and heat-treated under a nitrogen atmosphere to obtain heat-treated powder. The heat-treated powder is dissolved in water and acid is added, then filtered. The solid material obtained from the filtration is washed with water and dried to obtain alkali lignin byproduct.
2. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 1, characterized in that, Step S2 involves preparing an iron-manganese-doped carbon adsorbent using lignin, and includes the following steps: S2.1: Add FeCl3 and MnCl2 to the reaction tank respectively, then add 10-15 parts by volume of deionized water and 20-25 parts by volume of polyethylene glycol to the reaction tank, and dissolve and mix by mechanical stirring for 30-35 minutes, and adjust the pH of the solution in the reaction tank to 10-11 with 1 mol / L NaOH; S2.2: Next, stir the solution in the reaction chamber at a speed of 400-450 rpm for 30-35 min, then heat the reaction chamber to 180-200℃ and maintain the temperature for 20-24 h. Then let it stand and cool to room temperature. Use a magnet to separate the material in the reaction chamber from the supernatant to obtain magnetic material. Wash it three times with ultrapure water, dry it in an oven at 60-80℃ for 20-24 h, grind it through a 300-mesh sieve to obtain manganese ferrite. S2.3: Dissolve 2-3 parts by weight of lignin in 50-55 parts by volume of deionized water, heat to 70-80℃ and stir magnetically, then add 60-80 parts by volume of 0.5-1 mol / L NaHCO3 aqueous solution, and keep stirring magnetically to mix evenly to obtain intermediate I; S2.4: Mix 10-15 parts by volume of water and 0.2-0.4 parts by weight of manganese ferrite and stir to obtain a mixture. Add the mixture to intermediate I and react fully by magnetic stirring. Dry the precipitate in an oven at 60-70℃ for 20-24 hours to obtain intermediate II. Place intermediate II in a tube furnace and pyrolyze it under a nitrogen atmosphere. Then, take the material out of the tube furnace, grind it, and pass it through a 300-mesh sieve. Wash the sieved product with water and ethanol alternately three times, and dry it to obtain the iron-manganese-doped carbon adsorbent.
3. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 2, characterized in that, Step S3 involves treating the manganese sulfate solution by complexing and precipitating heavy metal ions through sodium lignosulfonate and iron-manganese-doped carbon adsorbent, including the following steps: S3.1: Add the treated manganese sulfate solution obtained in step S1 to a thermostatic magnetic stirrer, then add iron-manganese-doped carbon adsorbent and sodium lignosulfonate to the thermostatic magnetic stirrer, and adjust the pH of the system in the thermostatic magnetic stirrer to 5.5-6 by adding dilute sulfuric acid. S3.2: Start the thermostatic magnetic stirrer and stir magnetically for 100-120 minutes at 25-30℃. Then filter the material in the thermostatic magnetic stirrer with a 0.22um filter membrane to obtain filter residue and filtrate. Collect the filtrate, which is the manganese sulfate solution with heavy metal ions removed.
4. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 3, characterized in that, Step S4 involves the high-temperature pyrolysis of the filter residue in step S3 to prepare by-products, including the following steps: S4.1: Dissolve the filter residue from step S3 in 1 mol / L NaOH solution to obtain a suspension. Heat the suspension to boiling in an electric furnace, evaporate and dry the water, grind it, and put all the powder obtained from grinding into a tube furnace for heat treatment under a nitrogen atmosphere at a temperature of 360-440℃ for 0.5-1h to obtain heat-treated powder. S4.2: Dissolve the heat-treated powder in water, adjust the pH to 3-6 with acid, filter, remove the liquid portion, wash the solid obtained by filtration with water until the pH is neutral, and dry to obtain alkali lignin byproduct.
5. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 4, characterized in that, Step S1 is a preliminary treatment of the crude manganese sulfate solution, including the following steps: S1.1: Mix manganese dioxide ore powder, pyrite powder and sulfuric acid, and heat the mixture with steam to 90-100℃. Leach for 4-6 hours to obtain a leachate. Then add potassium removal agent and sulfuric acid to the leachate, adjust the pH of the leachate to 1-4, and control the temperature at 50-60℃. React for 1-2 hours, and then filter to obtain crude manganese sulfate solution. S1.2: Add 1 mol / L NaOH solution to the crude manganese sulfate solution until the pH reaches 6-7, and filter to remove solids to obtain the treated manganese sulfate solution.
6. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 5, characterized in that, In step S1.1, the mass ratio of manganese dioxide ore powder, pyrite powder and sulfuric acid is 1:(0.2-0.5):(0.35-0.65).
7. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 2, characterized in that, In step S2.1, the molar ratio of FeCl3 to MnCl2 is 2:(1-1.5).
8. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 2, characterized in that, In step S2.4, the tubular furnace is heated to 700-750℃ for pyrolysis for 1.5-2 hours, with a heating rate of 3-5℃ / min.
9. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 3, characterized in that, In step S3.1, the volume ratio of manganese sulfate solution, iron-manganese doped carbon adsorbent and sodium lignin sulfonate is (80-100):(1-2):(5-10).
10. The method for deep purification and impurity removal of electrolytic manganese dioxide using manganese sulfate solution according to claim 4, characterized in that, In step S4.1, the mass ratio of NaOH solution to filter residue in step S3 is 1:(1.5-2).