Method for recycling and reclamation of denitrated manganese residue

Abstract

The present application belongs to the technical field of energy conservation and environmental protection, and provides a method for recycling and reclamation of denitrated manganese residue. The method for recycling and reclamation of denitrated manganese residue provided by the present application comprises: mixing denitrated manganese residue, a powdery additive and hydrogen peroxide, performing a first oxidation reaction, and performing solid-liquid separation to obtain a filter residue; mixing the filter residue with an alkaline solution to obtain a mixture, introducing air into the mixture, performing a second oxidation reaction and solid-liquid separation to obtain a filtrate, and evaporating the filtrate to dryness to obtain a concentrated solid, wherein the main component of the concentrated solid is K2MnO4; and dissolving the concentrated solid in water, pressurizing same, introducing a mixed gas, and performing a disproportionation reaction to obtain an Mn-containing mixture, wherein the Mn-containing mixture comprises MnO2 and KMnO4. In the present application, the comprehensive utilization of Mn is achieved by means of a method comprising primary oxidation, secondary oxidation and valence-state-based separation, and the purification of recycled products is achieved by means of a green process flow.

Description

A method for the resource-based regeneration of denitrification manganese slag

[0001] This application claims priority to the application filed on November 1, 2024, with application number CN202411550714.X and entitled "A Method for Resource Regeneration of Denitrification Manganese Slag", the entire contents of which are incorporated herein by reference. Technical Field

[0002] This application belongs to the field of energy conservation and environmental protection technology, specifically relating to a method for the resource-based regeneration of denitrification manganese slag. Background Technology

[0003] With the development of industry, NO x It has become a major cause of air pollution. Currently, measures are being taken to address the issue of NO emissions, which are significant contributors to air pollution. x For flue gas denitrification, a manganese-based catalyst wet denitrification method has emerged. This method can perform denitrification at ambient temperature, and both the denitrification efficiency and the utilization efficiency of the denitrifying agent are very high. However, the treatment of the manganese slag solid waste generated after denitrification is an urgent problem to be solved.

[0004] Existing technologies for the resource utilization of manganese slag often generate secondary pollution. For example, a multifunctional long-lasting composite filler for water treatment is prepared using electrolytic manganese slag as raw material. This involves washing the electrolytic manganese slag to obtain a manganese-containing filtrate, adding a precipitant to the filtrate to obtain clean manganese slag, and then mixing the clean manganese slag with gravel, additives, and clay to produce the composite filler. While this solves the problem of treating electrolytic manganese slag, the composite filler generates secondary solid waste pollution with prolonged use. Another example is the preparation of mineral polymer materials from waste manganese slag. This involves mixing manganese slag, aluminous salts, kaolin, quartz sand, calcium oxide, water glass, an alkali activator, and a large amount of water, followed by grinding, mixing, and drying. This process generates wastewater. Furthermore, current treatment methods for manganese slag are limited to solidification for building material preparation and do not effectively utilize the manganese (Mn) element to produce high-value-added products. Summary of the Invention

[0005] In view of this, the purpose of this application is to provide a method for the resource-based regeneration of denitrification manganese slag. The method provided by this application generates no secondary pollution, is green and environmentally friendly, and can efficiently utilize the Mn element in the denitrification manganese slag to produce high value-added products.

[0006] To address the aforementioned technical problems, this application provides the following technical solution:

[0007] This application provides a method for the resource-based regeneration of denitrification manganese slag, comprising the following steps:

[0008] The denitrification manganese slag, powdered additives, and hydrogen peroxide are mixed, and a first oxidation reaction occurs, followed by solid-liquid separation to obtain filter residue; the powdered additives include alkaline sodium salts;

[0009] The filter residue is mixed with an alkaline solution to obtain a mixture. Air is introduced into the mixture to cause a second oxidation reaction, resulting in solid-liquid separation and obtaining a filtrate. The filtrate is evaporated to dryness to obtain a concentrated solid. The main component of the concentrated solid is K2MnO4.

[0010] The concentrated solid was dissolved in water, pressurized, and a mixed gas was introduced to induce a disproportionation reaction, yielding a mixture containing Mn.

[0011] The Mn-containing mixture includes MnO2 and KMnO4;

[0012] The mixed gas includes CO2 and O2.

[0013] Preferably, the alkaline sodium salt includes any two of Na2CO3, NaHCO3, CH3COONa, and Na2C2O4;

[0014] The mass ratio of any two of the alkaline sodium salts is 0.5:1 to 2:1.

[0015] Preferably, the mass ratio of the denitrified manganese slag to the powdered additive is 100:1 to 100:10.

[0016] Preferably, the hydrogen peroxide has a mass concentration of 10-18%;

[0017] The mass ratio of the denitrified manganese slag to hydrogen peroxide is 1:2 to 1:5.

[0018] Preferably, the solute in the alkaline solution includes KOH and K2CO3, and the mass ratio of KOH to K2CO3 is 5:1 to 10:1.

[0019] Preferably, the alkaline solution has a mass percentage of 0.1% to 1%;

[0020] The mass ratio of the filter residue to the alkaline solution is 1:2 to 1:5.

[0021] Preferably, the ratio of the hourly air volume to the alkaline solution volume is 120:1 to 240:1.

[0022] Preferably, the mass ratio of the concentrated solid to water is 1:10 to 1:20.

[0023] Preferably, the volume ratio of CO2 to O2 is 5:1 to 10:1.

[0024] Preferably, the volume ratio of the mixed gas introduced per hour to the volume of water is 60:1 to 120:1.

[0025] This application provides a method for the resource-based regeneration of denitrification manganese slag, comprising the following steps: mixing denitrification manganese slag, powdered additives, and hydrogen peroxide, undergoing a first oxidation reaction, and separating the solid and liquid to obtain filter residue; the powdered additives include alkaline sodium salts; mixing the filter residue with an alkaline solution to obtain a mixture, introducing air into the mixture, undergoing a second oxidation reaction, separating the solid and liquid to obtain a filtrate, and evaporating the filtrate to obtain a concentrated solid; the main component of the concentrated solid is K2MnO4; dissolving the concentrated solid in water, pressurizing, introducing a mixed gas, and undergoing a disproportionation reaction to obtain a Mn-containing mixture; the Mn-containing mixture includes MnO2 and KMnO4; the mixed gas includes CO2 and O2. This application achieves comprehensive utilization of Mn element through primary oxidation, secondary oxidation, and valence state separation, while simultaneously purifying and concentrating the resource-based products through a green process. It can solve the problem of denitrification manganese slag treatment and disposal while generating two economically valuable by-products, resulting in good environmental and economic benefits. The test results show that the method provided in this application achieves a resource recovery rate of over 90% for Mn element in denitrification manganese slag, and the yield of KMnO4 in the resulting Mn-containing mixture is >60%.

[0026] The beneficial effects of this application are:

[0027] (1) The process is simple, green and economical, and no secondary pollution is generated throughout the process.

[0028] (2) The byproduct KMnO4 obtained in this application can be used again for low-temperature denitrification, and the byproduct MnO2 can be used again to prepare KMnO4.

[0029] (3) The resource utilization rate of Mn element in this application is >90%, and the yield of KMnO4 in the by-product is >60%. Attached Figure Description

[0030] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0031] Figure 1 is a process flow diagram of an embodiment of this application;

[0032] Figure 2 shows the XPS spectrum of the Mn-containing mixture obtained in Example 1. Detailed Implementation

[0033] This application provides a method for the resource-based regeneration of denitrification manganese slag, comprising the following steps:

[0034] The denitrification manganese slag, powdered additives, and hydrogen peroxide are mixed, and a first oxidation reaction occurs, followed by solid-liquid separation to obtain filter residue; the powdered additives include alkaline sodium salts;

[0035] The filter residue is mixed with an alkaline solution to obtain a mixture. Air is introduced into the mixture to cause a second oxidation reaction, resulting in solid-liquid separation and obtaining a filtrate. The filtrate is evaporated to dryness to obtain a concentrated solid. The main component of the concentrated solid is K2MnO4.

[0036] The concentrated solid was mixed with water, pressurized, and a mixed gas was introduced to induce a disproportionation reaction, yielding a mixture containing Mn.

[0037] The Mn-containing mixture includes MnO2 and KMnO4;

[0038] The mixed gas includes CO2 and O2.

[0039] Unless otherwise specified, all raw materials involved in this application are commercially available products well known in the art.

[0040] This application involves mixing denitrified manganese slag, powdered additives, and hydrogen peroxide to undergo a first oxidation reaction, followed by solid-liquid separation to obtain filter residue.

[0041] In this application, the denitrified manganese slag preferably comprises: 0.35–0.90 at% S, 14.5–47.2 at% C, 2.5–17.2 at% N, 27.2–44.1 at% O, and 7.3–12.6 at% Mn, more preferably 0.39–0.88 at% S, 14.57–47.15 at% C, 2.55–17.16 at% N, 27.32–44.04 at% O, and 7.49–12.565 at% Mn.

[0042] In this application, the powdered additive comprises an alkaline sodium salt, preferably any two of Na₂CO₃, NaHCO₃, CH₃COONa, and Na₂C₂O₄, and more preferably a combination of Na₂CO₃ and NaHCO₃, CH₃COONa and Na₂C₂O₄, or Na₂CO₃ and Na₂C₂O₄. In this application, the mass ratio of any two of the alkaline sodium salts is preferably 0.5:1 to 2:1. In specific embodiments, the mass ratio of any two can be 0.5:1, 1:1, or 2:1. The two mixed sodium salts act as a buffer to maintain the alkaline conditions of the solution.

[0043] In this application, the preferred mass ratio of the denitrified manganese slag to the powdered additive is 100:1 to 100:10. In specific embodiments, the mass ratio can be 100:1, 100:4, 100:7, or 100:10. The powdered additive provides an alkaline environment while releasing Na. + This promotes the contact between Mn elements and hydrogen peroxide in the denitrification manganese slag, thereby promoting the initial oxidation of low-valence manganese salts.

[0044] In this application, the hydrogen peroxide concentration is preferably 10-18%, and in specific embodiments, the hydrogen peroxide concentration can be 10%, 13%, 15%, or 18%. In this application, the mass ratio of the denitrified manganese slag to hydrogen peroxide is preferably 1:2 to 1:5, and in specific embodiments, the mass ratio can be 1:2, 1:3, 1:4, or 1:5. This application utilizes hydrogen peroxide in an alkaline environment to oxidize the easily oxidized solid low-valence manganese in the denitrified manganese slag; simultaneously, using hydrogen peroxide as a strong oxidant does not introduce additional elemental impurities, which can improve the effective purity of the subsequent Mn product.

[0045] This application does not specify any particular method for the mixing process; any technique commonly used in the field is acceptable. Specifically, the denitrification manganese slag and powdered additives are preferably mixed to obtain a mixture, and hydrogen peroxide is then added to the mixture.

[0046] In this application, the reaction temperature of the first oxidation reaction is preferably 25-30°C, and the reaction time is preferably 20-40 min, more preferably 30 min. This application preferably carries out the first oxidation reaction under stirring conditions.

[0047] This application does not have any special requirements for the solid-liquid separation; conventional solid-liquid separation methods in the art can be used. In a specific embodiment of this application, the solid-liquid separation is carried out by filtration.

[0048] In this application, the solid-liquid separation preferably further includes drying the resulting solid. This application does not specify a particular drying method; conventional techniques in the art, such as heating or natural air drying, are sufficient.

[0049] After obtaining the filter residue, this application mixes the filter residue with an alkaline solution to obtain a mixture, introduces air into the mixture to cause a second oxidation reaction, separates the solid and liquid, obtains a filtrate, and evaporates the filtrate to obtain a concentrated solid K2MnO4.

[0050] In this application, the solute in the alkaline solution preferably includes KOH and K₂CO₃, and the mass ratio of KOH to K₂CO₃ is preferably 5:1 to 10:1. In specific embodiments, the mass ratio of KOH to K₂CO₃ is 5:1, 6:1, 7:1, 8:1, 9:1, or 10:1. In this application, the mass percentage of the alkaline solution is preferably 0.1% to 1%. In specific embodiments, the mass percentage of the alkaline solution is 0.1%, 0.3%, or 1%. The alkaline solution provides an alkaline environment to ensure the smooth progress of the second oxidation reaction.

[0051] In this application, the mass ratio of the filter residue to the alkaline solution is preferably 1:2 to 1:5. In specific embodiments, the mass ratio of the filter residue to the alkaline solution is 1:2, 1:3, 1:4 or 1:5.

[0052] In this application, the volume ratio of air introduced per hour to the volume of alkaline solution is preferably 120:1 to 240:1. In specific embodiments, the volume ratio of air introduced per hour to the volume of alkaline solution is 120:1, 160:1, 180:1, 200:1, 220:1, or 240:1. In an alkaline environment, the introduction of air can dissolve sparingly soluble manganese salts into the liquid phase and further oxidize the low-valence manganese salts in the liquid phase to Mn. 6+ For compounds, the second oxidation step is a supplement to the first oxidation step.

[0053] In this application, the reaction temperature of the second oxidation reaction is preferably 25-30°C, and the reaction time is preferably 3-5 h, more preferably 3.5-4.5 h, and even more preferably 4 h.

[0054] This application does not specify a particular method for evaporating the filtrate; conventional techniques in the field are sufficient. For example, conventional heating evaporation or vacuum heating evaporation.

[0055] After obtaining the concentrated solid, this application mixes the concentrated solid with water, pressurizes it, introduces a mixed gas, and causes a disproportionation reaction to obtain a mixture containing Mn.

[0056] In this application, the mass ratio of the concentrated solid to water is preferably 1:10 to 1:20. In specific embodiments, the mass ratio of the concentrated solid to water is 1:10, 1:15, or 1:20.

[0057] In this application, the pressure applied is preferably 0.05 to 0.15 MPa. In specific embodiments, the pressure applied is 0.05 MPa, 0.1 MPa, or 0.15 MPa.

[0058] In this application, the mixed gas includes CO2 and O2, and the volume ratio of CO2 to O2 is preferably 5:1 to 10:1. In specific embodiments, the volume ratio of CO2 to O2 is 5:1, 8:1 or 10:1.

[0059] In this application, the volume ratio of the mixed gas introduced per hour to the water is preferably 60:1 to 120:1. In specific embodiments, the volume ratio of the mixed gas introduced per hour to the water is 60:1, 80:1, 100:1 or 120:1.

[0060] In this application, the temperature of the disproportionation reaction is preferably 25–80°C, and the time is preferably 0.5–3 hours. In the embodiments of this application, the temperature of the disproportionation reaction can specifically be 25°C, 30°C, 40°C, 45°C, 50°C, 55°C, 60°C, 70°C, 75°C, or 80°C, and the time can specifically be 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours, or 3 hours.

[0061] In this application, after obtaining the Mn-containing mixture, it is preferable to further perform solid-liquid separation to obtain a liquid and a solid, evaporate the liquid, and dry the solid.

[0062] Specifically, the liquid is evaporated to obtain KMnO4, and the solid is dried to obtain MnO2.

[0063] The Mn-containing mixture obtained in this application has a Mn element content of 91-94% of the mass of Mn element in the denitrification manganese slag (i.e., the resource utilization rate of Mn), and a KMnO4 yield of 64-69% (referring to the percentage of KMnO4 in the total mass of KMnO4+MnO2).

[0064] To make the objectives, technical solutions, and advantages of the embodiments of this application clearer, the technical solutions of this application will be clearly and completely described below in conjunction with specific embodiments. The described embodiments are only some embodiments of this application, and not all embodiments. Any modifications, equivalent substitutions, improvements, etc., made to the implementation methods of this application based on the technical essence and general principles of this application without creative effort should be within the protection scope of this application.

[0065] Figure 1 is a process flow diagram of an embodiment of this application.

[0066] Example 1

[0067] The denitrification manganese slag composition is: 0.88 at% S, 47.15 at% C, 17.16 at% N, 27.32 at% O, and 7.49 at% Mn. The denitrification manganese slag and powdered additives are mixed evenly at a mass ratio of 100:1 to obtain a mixture. The powdered additives are composed of Na₂CO₃ and NaHCO₃ at a mass ratio of 2:1. 13% hydrogen peroxide is added to the mixture, and the mixture is stirred for 30 minutes at room temperature. The mass ratio of denitrification manganese slag to hydrogen peroxide is 1:2. The mixture is filtered, and the filter residue is dried to obtain dried filter residue.

[0068] The dried filter residue was added to a 0.3% (w / w) alkaline solution to obtain a mixed solution. The alkaline solution consisted of KOH and K₂CO₃ in a 5:1 (w / w) ratio, and the mass ratio of the dried filter residue to the alkaline mixed solution was 1:2. Air was bubbled into the mixed solution and stirred at room temperature for 4 hours. The mixture was then filtered, and the filtrate was retained. The ratio of the air volume to the volume of the alkaline solution bubbled per hour was 120:1. The filtrate was heated to evaporate the solvent, yielding a concentrated solid.

[0069] The concentrated solid was dissolved in water at a mass ratio of 1:15 and placed in a high-pressure reactor. The reaction was carried out under a positive pressure of 0.05 MPa for 4 hours. The gas introduced into the reactor was a mixture of CO2 and O2 at a volume ratio of 10:1, and the hourly gas flow rate was 60:1 (the volume ratio of the mixed gas to the water in the reactor was also 60:1). After the reaction, a Mn-containing mixture was obtained. The mixture was then subjected to solid-liquid separation to collect the liquid and solid. The solid was dried to obtain MnO2, and the liquid was evaporated to obtain KMnO4. Calculations showed that the resource recovery rate of Mn in the denitrification manganese slag was 93%, and the yield of KMnO4 as a byproduct was 67%.

[0070] XPS testing was performed on the Mn-containing mixture obtained in Example 1, and the results are shown in Figure 2. Figure 2 shows that the Mn components are mainly MnO2 and KMnO4.

[0071] Example 2

[0072] The denitrification manganese slag composition is: 0.39 at% S, 37.7 at% C, 5.3 at% N, 44.04 at% O, and 12.56 at% Mn. The denitrification manganese slag and powdered additives are mixed evenly at a mass ratio of 100:10 to obtain a mixture. The powdered additives are composed of CH3COONa and Na2C2O4 at a mass ratio of 1:1. 18% hydrogen peroxide is added to the mixture, and the mixture is stirred for 30 minutes at room temperature. The mass ratio of denitrification manganese slag to hydrogen peroxide is 1:3. The mixture is filtered, and the filter residue is dried to obtain dried filter residue.

[0073] The dried filter residue was added to a 0.1% (w / w) alkaline solution to obtain a mixed solution. The alkaline solution consisted of KOH and K₂CO₃ in a mass ratio of 10:1, and the mass ratio of the dried filter residue to the alkaline mixed solution was 1:4. Air was bubbled into the mixed solution and stirred at room temperature for 4 hours. The mixture was then filtered, and the filtrate was retained. The volume ratio of air bubbled per hour to the volume of alkaline solution was 180:1. The filtrate was heated to evaporate the solvent, yielding a concentrated solid.

[0074] The concentrated solid was dissolved in water at a mass ratio of 1:10 and placed in a high-pressure reactor. The reaction was carried out under a positive pressure of 0.1 MPa for 4 hours. The gas introduced into the reactor was a mixture of CO2 and O2 at a volume ratio of 8:1, and the hourly gas flow rate was 120:1 (the volume ratio of the mixed gas to the water in the reactor was also 120:1). After the reaction, a Mn-containing mixture was obtained. The mixture was then subjected to solid-liquid separation to collect the liquid and solid. The solid was dried to obtain MnO2, and the liquid was evaporated to obtain KMnO4. Calculations showed that the resource utilization rate of Mn in the denitrification manganese slag was 91%, and the yield of KMnO4 as a byproduct was 64%.

[0075] Example 3

[0076] The denitrification manganese slag composition is: 0.65 at% S, 14.57 at% C, 2.55 at% N, 42.96 at% O, and 12.28 at% Mn. The denitrification manganese slag and powdered additives are mixed evenly at a mass ratio of 100:7 to obtain a mixture. The powdered additives are composed of Na₂CO₃ and Na₂C₂O₄ at a mass ratio of 0.5:1. 10% hydrogen peroxide is added to the mixture, and the mixture is stirred for 30 minutes at room temperature. The mass ratio of denitrification manganese slag to hydrogen peroxide is 1:5. The mixture is filtered, and the filter residue is dried to obtain dried filter residue.

[0077] The dried filter residue was added to a 1% (w / w) alkaline solution to obtain a mixed solution. The alkaline solution consisted of KOH and K₂CO₃ in a mass ratio of 8:1, and the mass ratio of the dried filter residue to the alkaline mixed solution was 1:5. Air was bubbled into the mixed solution and stirred at room temperature for 4 hours. The mixture was then filtered, and the filtrate was retained. The volume ratio of air bubbled per hour to the volume of alkaline solution was 240:1. The filtrate was heated to evaporate the solvent, yielding a concentrated solid.

[0078] The concentrated solid was dissolved in water at a mass ratio of 1:20 and placed in a high-pressure reactor. The reaction was carried out under a positive pressure of 0.15 MPa for 4 hours. The gas introduced into the reactor was a mixture of CO2 and O2 at a volume ratio of 5:1, and the hourly gas flow rate was 100:1 (the volume ratio of the mixed gas to the water in the reactor was also 100:1). After the reaction, a Mn-containing mixture was obtained. The mixture was then subjected to solid-liquid separation to collect the liquid and solid. The solid was dried to obtain MnO2, and the liquid was evaporated to obtain KMnO4. Calculations showed that the resource recovery rate of Mn in the denitrification manganese slag was 94%, and the yield of KMnO4 as a byproduct was 69%.

[0079] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A method for the resource-based regeneration of denitrification manganese slag, characterized in that, Includes the following steps: The denitrified manganese slag, powdered additives, and hydrogen peroxide are mixed, and a first oxidation reaction occurs, followed by solid-liquid separation to obtain a solid; the powdered additives include alkaline sodium salts; The solid is mixed with an alkaline solution to obtain a mixture. Air is then introduced into the mixture to induce a second oxidation reaction, resulting in solid-liquid separation and the yield of a liquid. The liquid is then evaporated to dryness to obtain a concentrated solid. The main component of the concentrated solid is K2MnO4. The concentrated solid was dissolved in water, pressurized, and a mixed gas was introduced to induce a disproportionation reaction, yielding a mixture containing Mn. The Mn-containing mixture includes MnO2 and KMnO4; The mixed gas includes CO2 and O2.

2. The resource recycling method according to claim 1, characterized in that, The alkaline sodium salt includes any two of Na2CO3, NaHCO3, CH3COONa, and Na2C2O4; The mass ratio of any two of the alkaline sodium salts is 0.5:1 to 2:

1.

3. The resource recycling method according to claim 2, characterized in that, When one of the alkaline sodium salts is Na2C2O4, the mass ratio of the other alkaline sodium salt to Na2C2O4 is 0.5:1 to 2:

1. When one of the alkaline sodium salts is Na2CO3 and does not contain Na2C2O4, the mass ratio of the other alkaline sodium salt to Na2CO3 is 0.5:1 to 2:

1.

4. The resource recycling method according to claim 1 or 2, characterized in that, The mass ratio of the denitrified manganese slag to the powdered additive is 100:1 to 100:

10.

5. The resource recycling method according to claim 1, characterized in that, The hydrogen peroxide has a mass concentration of 10-18%. The mass ratio of the denitrified manganese slag to hydrogen peroxide is 1:2 to 1:

5.

6. The resource recycling method according to claim 1, characterized in that, The solutes in the alkaline solution include KOH and K2CO3, and the mass ratio of KOH to K2CO3 is 5:1 to 10:

1.

7. The resource recycling method according to claim 1 or 6, characterized in that, The alkaline solution has a mass percentage of 0.1% to 1%. The mass ratio of the filter residue to the alkaline solution is 1:2 to 1:

5.

8. The resource recycling method according to claim 1, characterized in that, The ratio of the hourly air volume to the alkaline solution volume is 120:1 to 240:

1.

9. The resource recycling method according to claim 1, characterized in that, The mass ratio of the concentrated solid to water is 1:10 to 1:

20.

10. The resource recycling method according to claim 1, characterized in that, The volume ratio of CO2 to O2 is 5:1 to 10:

1.

11. The resource recycling method according to claim 1 or 10, characterized in that, The hourly volume ratio of the mixed gas to the water is 60:1 to 120:

1.

12. The resource recycling method according to claim 1, characterized in that, The reaction temperature of the first oxidation reaction is 25-30℃, and the reaction time is 20-40 min.

13. The resource recycling method according to claim 1, characterized in that, The reaction temperature for the second oxidation reaction is 25–30°C, and the reaction time is 3–5 hours.

14. The resource recycling method according to claim 1 or 8, characterized in that, The applied pressure is 0.05–0.15 MPa.

15. The resource recycling method according to claim 1, characterized in that, The disproportionation reaction is carried out at a temperature of 25–80°C for a time of 0.5–3 hours.

16. The resource recycling method according to claim 1, characterized in that, The mass percentage of Mn in the Mn-containing mixture is 91-94% of the mass percentage of Mn in the denitrification manganese slag. The mass percentage of KMnO4 in the Mn-containing mixture is 64-69%.

17. The resource recycling method according to claim 1, characterized in that, The denitrified manganese slag comprises the following elemental components: 0.35–0.90 at% S, 14.5–47.2 at% C, 2.5–17.2 at% N, 27.2–44.1 at% O, and 7.3–12.6 at% Mn.

18. The resource recycling method according to claim 1, characterized in that, The solid-liquid separation is filtration, and the solid is filter residue.

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