Method for resource regeneration of denitration manganese slag

Abstract

The invention provides a method for resource regeneration of denitration manganese slag, and belongs to the technical field of energy conservation and environmental protection. The method comprises the following steps: mixing the denitration manganese slag, a powdery additive and hydrogen peroxide, carrying out a first oxidation reaction, and carrying out solid-liquid separation to obtain filter residues; mixing the filter residue with an alkaline solution to obtain a mixture, introducing air into the mixture, carrying out a second oxidation reaction and solid-liquid separation to obtain a filtrate, and evaporating the filtrate to dryness to obtain a concentrated solid; the main component of the concentrated solid is K2MnO4; dissolving the concentrated solid in water, pressurizing, introducing mixed gas, and carrying out disproportionation reaction to obtain a Mn-containing mixture; the Mn-containing mixture comprises MnO2 (manganese dioxide) and KMnO4 (potassium manganese oxide). According to the method, the comprehensive utilization of the Mn element is realized through primary oxidation, secondary oxidation and valence state separation, and the purification of resource products is realized through a green process flow.

Description

Technical Field

[0001] The invention belongs to the technical field of energy conservation and environmental protection, and specifically relates to a method for resource regeneration of denitrified manganese slag. Background Art

[0002] With the development of industry, NO x It has become the main cause of air pollution. x Flue gas has been denitrated by wet denitration using manganese-based catalysts. This method can denitrate at room temperature, and the denitration efficiency and denitrification agent utilization efficiency are both very high. However, the treatment of manganese slag solid waste generated after denitration is an urgent problem to be solved.

[0003] In the prior art, resource recovery treatment of manganese slag usually generates secondary pollution. For example, a multifunctional long-lasting composite filler for water treatment is prepared using electrolytic manganese slag as raw material. Although this solves the problem of treating electrolytic manganese slag, the long-term use of the filler will generate secondary solid waste pollution. For another example, waste manganese slag is used to prepare mineral polymer materials, and wastewater is generated during the production process. In addition, the current treatment of manganese slag is still limited to the solidification and preparation of building materials, and the Mn element therein is not effectively used to produce high value-added products. Summary of the invention

[0004] In view of this, the object of the present invention is to provide a method for resource regeneration of denitrified manganese slag. The method provided by the present invention does not generate secondary pollution, is green and environmentally friendly, and can efficiently utilize the Mn element in the denitrified manganese slag to produce high value-added products.

[0005] In order to solve the above technical problems, the present invention provides the following technical solutions:

[0006] The present invention provides a method for resource regeneration of denitrified manganese slag, comprising the following steps:

[0007] Mixing denitrified manganese slag, powdered additive and hydrogen peroxide to cause a first oxidation reaction, separate the solid and liquid, and obtain filter residue; the powdered additive includes alkaline sodium salt;

[0008] 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, solid-liquid separation is performed to obtain a filtrate, and the filtrate is evaporated to dryness to obtain a concentrated solid; the main component of the concentrated solid is K2MnO4;

[0009] The concentrated solid is dissolved in water, pressurized, and introduced with a mixed gas to cause a disproportionation reaction to obtain a Mn-containing mixture;

[0010] The Mn-containing mixture includes MnO2 and KMnO4;

[0011] The mixed gas includes CO2 and O2.

[0012] Preferably, the alkaline sodium salt includes any two of Na2CO3, NaHCO3, CH3COONa and Na2C2O4;

[0013] The mass ratio of any two of the alkaline sodium salts is 0.5:1 to 2:1.

[0014] Preferably, the mass ratio of the denitrification manganese slag to the powdered additive is 100:1 to 100:10.

[0015] Preferably, the mass concentration of the hydrogen peroxide is 10-18%;

[0016] The mass ratio of the denitrified manganese slag to hydrogen peroxide is 1:2 to 1:5.

[0017] Preferably, the solute of the alkaline solution includes KOH and K2CO3, and the mass ratio of KOH to K2CO3 is 5:1 to 10:1.

[0018] Preferably, the mass percentage of the alkaline solution is 0.1-1%;

[0019] The mass ratio of the filter residue to the alkaline solution is 1:2 to 1:5.

[0020] Preferably, the volume ratio of the air introduced per hour to the alkaline solution is 120:1 to 240:1.

[0021] Preferably, the mass ratio of the concentrated solid to water is 1:10 to 1:20.

[0022] Preferably, the volume ratio of CO2 to O2 is 5:1 to 10:1.

[0023] Preferably, the volume ratio of the hourly introduced volume of the mixed gas to the volume of water is 60:1 to 120:1.

[0024] The present invention provides a method for resource regeneration of denitrified manganese slag, comprising the following steps: mixing denitrified manganese slag, powdered additive and hydrogen peroxide, causing a first oxidation reaction, solid-liquid separation, and obtaining filter residue; the powdered additive comprises alkaline sodium salt; mixing the filter residue with an alkaline solution to obtain a mixture, introducing air into the mixture, causing a second oxidation reaction, solid-liquid separation, obtaining a filtrate, 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, causing a disproportionation reaction, and obtaining a Mn-containing mixture; the Mn-containing mixture comprises MnO2 and KMnO4; the mixed gas comprises CO2 and O2. The present invention realizes the comprehensive utilization of the Mn element through the methods of primary oxidation, secondary oxidation and valence separation, and at the same time realizes the purification and concentration of the resource product through a green process flow, and can produce two by-products with economic value while solving the problem of denitrified manganese slag treatment and disposal, and has good environmental and economic benefits. The test results show that the method provided by the present invention can achieve a resource utilization rate of more than 90% for the Mn element in the denitrified manganese slag, and the yield of KMnO4 in the obtained Mn-containing mixture is >60%.

[0025] Beneficial effects of the present invention:

[0026] (1) The process is simple, green and economical, and no secondary pollution is generated during the whole process.

[0027] (2) The by-product KMnO4 produced by the present invention can be used again for low-temperature denitration, and the by-product MnO2 can be used again for the preparation of KMnO4.

[0028] (3) The resource utilization rate of the Mn element in the present invention is greater than 90%, and the yield of KMnO4 in the obtained by-product is greater than 60%. BRIEF DESCRIPTION OF THE DRAWINGS

[0029] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative labor.

[0030] Figure 1 is a process flow chart of an embodiment of the present invention;

[0031] Figure 2 This is the XPS spectrum of the Mn-containing mixture obtained in Example 1. DETAILED DESCRIPTION

[0032] The present invention provides a method for resource regeneration of denitrified manganese slag, comprising the following steps:

[0033] Mixing denitrified manganese slag, powdered additive and hydrogen peroxide to cause a first oxidation reaction, separate the solid and liquid, and obtain filter residue; the powdered additive includes alkaline sodium salt;

[0034] 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, solid-liquid separation is performed to obtain a filtrate, and the filtrate is evaporated to dryness to obtain a concentrated solid; the main component of the concentrated solid is K2MnO4;

[0035] The concentrated solid is mixed with water, pressurized, and introduced with a mixed gas to cause a disproportionation reaction to obtain a Mn-containing mixture;

[0036] The Mn-containing mixture includes MnO2 and KMnO4;

[0037] The mixed gas includes CO2 and O2.

[0038] In the present invention, unless otherwise specified, the raw materials involved are commercially available products well known in the art.

[0039] The invention mixes denitrified manganese slag, powdery additives and hydrogen peroxide, generates a first oxidation reaction, separates the solid and the liquid, and obtains filter residue.

[0040] In the present invention, the denitrification manganese slag preferably comprises: 0.35-0.90at% S, 14.5-47.2at% C, 2.5-17.2at% N, 27.2-44.1at% O and 7.3-12.6at% Mn, more preferably 0.39-0.88at% S, 14.57-47.15at% C, 2.55-17.16at% N, 27.32-44.04at% O and 7.49-12.565at% Mn.

[0041] In the present invention, the powdered additive includes an alkaline sodium salt, and the alkaline sodium salt preferably includes any two of Na2CO3, NaHCO3, CH3COONa, and Na2C2O4, preferably a combination of Na2CO3 and NaHCO3, a combination of CH3COONa and Na2C2O4, or a combination of Na2CO3 and Na2C2O4. In the present invention, the mass ratio of any two of the alkaline sodium salts is preferably 0.5:1 to 2:1. In a specific embodiment, the mass ratio of any two of the alkaline sodium salts can be 0.5:1, 1:1 or 2:1. The two mixed Na salts play a buffering role in maintaining the alkaline conditions of the solution.

[0042] In the present invention, the mass ratio of the denitrified manganese slag to the powdered additive is preferably 100:1 to 100:10. In a specific embodiment, the mass ratio of the denitrified manganese slag to the powdered additive may be 100:1, 100:4, 100:7 or 100:10. The powdered additive provides an alkaline environment and releases Na + , promoting the contact between Mn element and hydrogen peroxide in denitrification manganese slag, thereby promoting the initial oxidation of low-valent manganese salts.

[0043] In the present invention, the mass concentration of the hydrogen peroxide is preferably 10-18%. In a specific embodiment, the mass concentration of the hydrogen peroxide can be 10%, 13%, 15% or 18%. In the present invention, the mass ratio of the denitrified manganese slag to the hydrogen peroxide is preferably 1:2-1:5. In a specific embodiment, the mass ratio of the denitrified manganese slag to the hydrogen peroxide can be 1:2, 1:3, 1:4 or 1:5. The present invention utilizes hydrogen peroxide to oxidize the easily oxidized solid low-valent manganese in the denitrified manganese slag in an alkaline environment; at the same time, using hydrogen peroxide as a strong oxidant will not introduce additional element impurities, and can improve the effective purity of the subsequent Mn product.

[0044] The present invention has no special requirements for the mixing method, and the commonly used technical means in the art can be used. Specifically, the denitrified manganese slag and the powdered additive are preferably mixed to obtain a mixture, and hydrogen peroxide is added to the mixture.

[0045] In the present invention, the reaction temperature of the first oxidation reaction is preferably 25-30°C, the time is preferably 20-40 minutes, and more preferably 30 minutes. In the present invention, the first oxidation reaction is preferably carried out under stirring conditions.

[0046] The present invention has no special requirements for the solid-liquid separation, and conventional solid-liquid separation methods in the art can be used. In a specific embodiment of the present invention, the solid-liquid separation is performed by filtering.

[0047] In the present invention, after the solid-liquid separation, the obtained solid is preferably dried. The present invention has no special requirements for the drying method, and conventional technical means in the art can be used, such as heating or natural drying.

[0048] After obtaining the filter residue, the present invention 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 the liquid to obtain a filtrate, and evaporates the filtrate to obtain concentrated solid K2MnO4.

[0049] In the present invention, the solute of the alkaline solution preferably includes KOH and K2CO3, and the mass ratio of KOH and K2CO3 is preferably 5:1 to 10:1. In a specific embodiment, the mass ratio of KOH and K2CO3 is 5:1, 6:1, 7:1, 8:1, 9:1 or 10:1. In the present invention, the mass percentage of the alkaline solution is preferably 0.1% to 1%. In a specific embodiment, the mass percentage of the alkaline solution is 0.1%, 0.3% or 1%. The alkaline solution provides an alkaline environment to ensure that the second oxidation reaction proceeds smoothly.

[0050] In the present invention, the mass ratio of the filter residue to the alkaline solution is preferably 1:2 to 1:5. In a specific embodiment, the mass ratio of the filter residue to the alkaline solution is 1:2, 1:3, 1:4 or 1:5.

[0051] In the present invention, the volume ratio of the air volume introduced per hour to the alkaline solution is preferably 120:1 to 240:1. In a specific embodiment, the volume ratio of the air volume introduced per hour to the 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 the insoluble manganese salt into the liquid phase and further oxidize the low-valent manganese salt in the liquid phase into Mn 6+ Compound, the second oxidation step is the complement of the first oxidation step.

[0052] In the present invention, the reaction temperature of the second oxidation reaction is preferably 25 to 30° C., and the time is preferably 3 to 5 hours, more preferably 3.5 to 4.5 hours, and more preferably 4 hours.

[0053] The present invention has no special requirements for the method of evaporating the filtrate to dryness, and conventional technical means in the art may be used, such as conventional heating evaporation or vacuum heating evaporation.

[0054] After the concentrated solid is obtained, the present invention mixes the concentrated solid with water, pressurizes it, introduces a mixed gas, and causes a disproportionation reaction to occur, thereby obtaining a Mn-containing mixture.

[0055] In the present invention, the mass ratio of the concentrated solid to water is preferably 1:10 to 1:20. In a specific embodiment, the mass ratio of the concentrated solid to water is 1:10, 1:15 or 1:20.

[0056] In the present invention, the pressurized pressure is preferably 0.05-0.15 MPa. In a specific embodiment, the pressurized pressure is 0.05 MPa, 0.1 MPa or 0.15 MPa.

[0057] In the present invention, the mixed gas includes CO2 and O2, and the volume ratio of CO2 to O2 is preferably 5:1 to 10:1. In a specific embodiment, the volume ratio of CO2 to O2 is 5:1, 8:1 or 10:1.

[0058] In the present invention, the volume ratio of the mixed gas introduced per hour to the volume of water is preferably 60:1 to 120:1. In a specific embodiment, the volume ratio of the mixed gas introduced per hour to the volume of water is 60:1, 80:1, 100:1 or 120:1.

[0059] In the present invention, the temperature of the disproportionation reaction is preferably 25 to 80° C., and the time is preferably 0.5 to 3 hours. In an embodiment of the present invention, the temperature of the disproportionation reaction can be specifically 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 be specifically 0.5 hours, 1 hour, 1.5 hours, 2 hours, 2.5 hours or 3 hours.

[0060] In the present invention, after obtaining the Mn-containing mixture, preferably the process further includes solid-liquid separation to obtain a liquid and a solid, evaporating the liquid, and drying the solid.

[0061] Specifically, the liquid is evaporated to obtain KMnO4, and the solid is dried to obtain MnO2.

[0062] The mass percentage of Mn element in the Mn-containing mixture obtained by the present invention to the Mn element in the denitrified manganese slag is 91-94% (i.e., the resource utilization rate of Mn), and the yield of KMnO4 is 64-69% (referring to the percentage of KMnO4 to the total mass of KMnO4+MnO2).

[0063] In order to make the purpose, technical solution and advantages of the embodiments of the present invention clearer, the technical solution of the present invention will be clearly and completely described in conjunction with specific embodiments below. The described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Any modification, equivalent replacement, improvement, etc. made to the implementation methods of the present invention based on the technical essence and general principles of the present invention without creative work should be within the scope of protection of the present invention.

[0064] Figure 1 The process flow chart of an embodiment of the present invention.

[0065] Example 1

[0066] The denitrification manganese slag is composed of 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 the powdered additive are mixed uniformly at a mass ratio of 100:1 to obtain a mixture, wherein the powdered additive is composed of Na2CO3 and NaHCO3 at a mass ratio of 2:1. Hydrogen peroxide with a mass concentration of 13% is added to the mixture, and stirred for 30 minutes at room temperature, wherein the mass ratio of the denitrification manganese slag to the hydrogen peroxide is 1:2, filtered, and the filter residue is dried to obtain a dried filter residue.

[0067] Add the dried filter residue to an alkaline solution with a mass percentage of 0.3% to obtain a mixed solution, wherein the alkaline solution is composed of KOH and K2CO3 in a mass ratio of 5:1, and the mass ratio of the dried filter residue to the alkaline mixed solution is 1:2. Air is introduced into the mixed solution and stirred for 4 hours at room temperature, filtered, and the filtrate is retained. The volume ratio of the air volume introduced per hour to the alkaline solution is 120:1. The filtrate is heated to evaporate the solvent in the solution to obtain a concentrated solid.

[0068] The concentrated solid was dissolved in water, the mass ratio of the concentrated solid to water was 1:15, and placed in a high-pressure reactor, and reacted for 4 hours under a positive pressure of 0.05MPa. The gas introduced into the high-pressure reactor was a mixture of CO2 and O2, the volume ratio of CO2 and O2 was 10:1, and the volume ratio of the mixed gas introduced per hour to the water in the high-pressure reactor was 60:1. After the reaction, a Mn-containing mixture was obtained, and the Mn-containing mixture was subjected to solid-liquid separation to collect liquid and solid, and the solid was dried to obtain MnO2, and the liquid was heated and evaporated to obtain KMnO4. According to calculations, the resource utilization rate of the Mn element in the denitrification manganese slag is 93%, and the yield of KMnO4 in the obtained by-product is 67%.

[0069] The Mn-containing mixture obtained in Example 1 was subjected to XPS testing, and the results obtained were as follows: Figure 2 As shown. Figure 2 It can be seen that the main Mn components are MnO2 and KMnO4.

[0070] Example 2

[0071] The denitrification manganese slag is composed of 0.39at% S, 37.7at% C, 5.3at% N, 44.04at% O and 12.56at% Mn. The denitrification manganese slag and the powdered additive are mixed uniformly at a mass ratio of 100:10 to obtain a mixture, wherein the powdered additive is composed of CH3COONa and Na2C2O4 at a mass ratio of 1:1. Hydrogen peroxide with a mass concentration of 18% is added to the mixture, and stirred for 30 minutes at room temperature, wherein the mass ratio of the denitrification manganese slag to the hydrogen peroxide is 1:3, filtered, and the filter residue is dried to obtain a dried filter residue.

[0072] Add the dried filter residue to an alkaline solution with a mass percentage of 0.1% to obtain a mixed solution, wherein the alkaline solution is composed 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 is 1:4. Pass air into the mixed solution and stir for 4 hours at room temperature, filter, and retain the filtrate, wherein the volume ratio of the air volume passed per hour to the alkaline solution is 180:1. Heat the filtrate and evaporate the solvent in the solution to obtain a concentrated solid.

[0073] The concentrated solid is dissolved in water, the mass ratio of the concentrated solid to water is 1:10, and placed in a high-pressure reactor, and reacted for 4 hours under a positive pressure of 0.1MPa. The gas introduced into the high-pressure reactor is a mixture of CO2 and O2, the volume ratio of CO2 and O2 is 8:1, and the volume ratio of the mixed gas introduced per hour to the water in the high-pressure reactor is 120:1. After the reaction is completed, a Mn-containing mixture is obtained, and the Mn-containing mixture is subjected to solid-liquid separation to collect liquid and solid, and the solid is dried to obtain MnO2, and the liquid is heated and evaporated to obtain KMnO4. According to calculations, the resource utilization rate of the Mn element in the denitrification manganese slag is 91%, and the yield of KMnO4 in the obtained by-product is 64%.

[0074] Example 3

[0075] The denitrification manganese slag is composed of 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 the powdered additive are mixed uniformly at a mass ratio of 100:7 to obtain a mixture, wherein the powdered additive is composed of Na2CO3 and Na2C2O4 at a mass ratio of 0.5:1. Hydrogen peroxide with a mass concentration of 10% is added to the mixture, and stirred for 30 minutes at room temperature, wherein the mass ratio of the denitrification manganese slag to the hydrogen peroxide is 1:5, filtered, and the filter residue is dried to obtain a dried filter residue.

[0076] Add the dried filter residue to a 1% alkaline solution by mass to obtain a mixed solution, wherein the alkaline solution is composed 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 is 1:5. Pass air into the mixed solution and stir for 4 hours at room temperature, filter, and retain the filtrate, wherein the volume ratio of the air volume passed per hour to the alkaline solution is 240:1. Heat the filtrate and evaporate the solvent in the solution to obtain a concentrated solid.

[0077] The concentrated solid is dissolved in water, the mass ratio of the concentrated solid to water is 1:20, and placed in a high-pressure reactor, and aerated for 4 hours under a positive pressure of 0.15MPa. The gas introduced into the high-pressure reactor is a mixture of CO2 and O2, the volume ratio of CO2 and O2 is 5:1, and the volume ratio of the mixed gas introduced per hour to the water in the high-pressure reactor is 100:1. After the reaction is completed, a Mn-containing mixture is obtained, and the Mn-containing mixture is subjected to solid-liquid separation to collect liquid and solid, and the solid is dried to obtain MnO2, and the liquid is heated and evaporated to obtain KMnO4. According to calculations, the resource utilization rate of the Mn element in the denitrified manganese slag is 94%, and the yield of KMnO4 in the obtained by-product is 69%.

[0078] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A method for resource regeneration of denitrified manganese slag, characterized in that: The following steps are involved: Mixing denitrified manganese slag, powdered additive and hydrogen peroxide to cause a first oxidation reaction, separate the solid and liquid, and obtain filter residue; the powdered additive includes alkaline sodium salt; 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, solid-liquid separation is performed to obtain a filtrate, and the filtrate is evaporated to dryness to obtain a concentrated solid; the main component of the concentrated solid is K2MnO4; The concentrated solid is dissolved in water, pressurized, and introduced with a mixed gas to cause a disproportionation reaction to obtain a Mn-containing mixture; The Mn-containing mixture includes MnO2 and KMnO4; The mixed gas includes CO2 and O2.

2. The 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 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.

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

5.

5. The method according to claim 1, characterized in that The solute of the alkaline solution includes KOH and K2CO3, and the mass ratio of KOH to K2CO3 is 5:1 to 10:

1.

6. The method according to claim 1 or 5, characterized in that: The mass percentage of the alkaline solution is 0.1-1%; The mass ratio of the filter residue to the alkaline solution is 1:2 to 1:

5.

7. The method according to claim 1, characterized in that The volume ratio of the air introduced per hour to the alkaline solution is 120:1 to 240:

1.

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

20.

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

1.

10. The method according to claim 1 or 9, characterized in that: The volume ratio of the mixed gas introduced per hour to the water is 60:1 to 120:1.

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