VOCs (Volatile Organic Compounds) catalyst based on manganese slag as well as preparation method and application of VOCs catalyst and manganese slag resource utilization method

Abstract

The invention belongs to the technical field of solid waste control, and particularly relates to a VOCs catalyst based on manganese slag, a preparation method and application of the VOCs catalyst and a manganese slag resource utilization method. The method comprises the following steps: mixing manganese slag with a sulfuric acid solution, and carrying out solid-liquid separation to obtain a washing solution and washing slag; mixing the washing solution and the carbonate aqueous solution, and sequentially carrying out precipitation reaction, standing and solid-liquid separation to obtain a precipitate and a separation solution; roasting the precipitate to obtain a roasted substance, washing the roasted substance with an organic acid solution and water in sequence, and then drying to obtain a purified product; mixing the purified product, a binder and water to obtain a mixed material; the mixed material is subjected to extrusion molding and then dried, and the VOCs catalyst based on the manganese slag is obtained. According to the method, resource utilization of metal elements in the manganese slag is achieved, and the excellent VOCs catalytic oxidation effect is achieved on the premise that the production cost of the catalyst is greatly reduced.

Description

TECHNICAL FIELD

[0001] The present application belongs to the technical field of solid waste control, and particularly relates to a VOCs catalyst based on manganese slag, a preparation method and application thereof, and a manganese slag resource utilization method. BACKGROUND

[0002] Manganese has a very important strategic position in the national economy. With the rapid development of manganese-related industries, the problem of manganese slag resource utilization is increasingly prominent. Manganese slag is an industrial solid waste generated in the production process of electrolytic manganese and manganese sulfate industry, generally acidic, and mainly composed of gypsum, quartz, and heavy metals such as manganese, iron, magnesium, cobalt, nickel, and ammonium salt. Its composition is very complex and is difficult to handle and resource utilization.

[0003] In terms of manganese slag resource utilization, the most commonly used methods currently include recovering valuable metals, preparing fertilizers, using as cement additives, producing wall materials and roadbed materials, etc., which have low market value. In recent years, many scholars have made beneficial explorations and developed some high-value utilization technologies of manganese slag with catalyst as the core. For example, a related technology discloses a preparation method and application of a manganese slag-based copper-manganese-iron catalyst. After ball milling of the manganese slag, a pore-forming agent solution is added, dried and calcined, then an equal volume of copper solution is impregnated, dried and calcined in air, and then pressed into a tablet with graphite to obtain the final catalyst, which is used for benzyl alcohol oxidation reaction. A related technology discloses an electrolytic manganese slag-based micro-mesoporous ZSM-5 catalyst and a preparation method. NaOH solution is added to the manganese slag, which is calcined and then mixed with tetrapropylammonium hydroxide solution and cerium nitrate solution at a certain ratio and heated. Then, polydiene dimethyl ammonium chloride solution is added to the solution, which is mixed and heated, and then crystallized in a reaction kettle. After filtration, washing, drying and calcination, the final catalyst is obtained. The catalyst can be used for catalytic oxidation treatment of cooking oil VOCs.

[0004] However, the above technical solutions need to add other metal solutions such as copper and cerium to improve the catalytic activity, which increases the difficulty of treatment and increases the cost of treatment. SUMMARY

[0005] The present application provides a VOCs catalyst based on manganese slag, a preparation method and application thereof, and a manganese slag resource utilization method. The present application realizes manganese slag resource utilization, realizes the preparation of a VOCs catalyst based on manganese slag without additional metal elements, and the obtained VOCs catalyst based on manganese slag has excellent VOCs catalytic oxidation effect. The method provided by the present application has low treatment difficulty and low cost.

[0006] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0007] The application provides a preparation method of a manganese residue-based VOCs catalyst, comprising the following steps:

[0008] S1, mixing manganese residue and sulfuric acid solution, and obtaining washing liquid and washing residue after solid-liquid separation;

[0009] S2, sequentially performing precipitation reaction, standing and solid-liquid separation on the washing liquid and aqueous carbonate solution mixture to obtain precipitate and separation liquid;

[0010] S3, roasting the precipitate to obtain roasted material, the atmosphere of roasting is air; washing the roasted material with organic acid solution and water in sequence, and then drying to obtain purified product; mixing the purified product, binder and water to obtain mixed material; extruding the mixed material to obtain wet molded body, and drying the wet molded body to obtain the manganese residue-based VOCs catalyst.

[0011] Preferably, in step S1, the manganese residue is manganese residue after crushing, the average particle size of the manganese residue is ≤0.5 cm; the mass content of H2SO4 in the sulfuric acid solution is 5-30%; the mass ratio of the sulfuric acid solution to the manganese residue is 3-30:1; the mixing temperature is 20-80℃, the mixing time is 1-6h, the mixing is performed under stirring, and the stirring speed is 300-1500r / min.

[0012] Preferably, in step S2, the aqueous carbonate solution contains water-soluble carbonate, the mass of the water-soluble carbonate in the aqueous carbonate solution is 1.1 times the mass of water-soluble carbonate required for neutralizing the sulfuric acid solution in step S1; the precipitation reaction temperature is 20-50℃, the precipitation reaction time is 0.5-2h, the precipitation reaction is performed under stirring, and the stirring speed is 100-1000r / min; the standing time is 6-24h.

[0013] Preferably, in step S3, before roasting, the precipitate is sequentially washed with water and dried, the drying temperature of the precipitate is 60-120℃, and the drying time is 6-24h; the precipitate is also washed with water to obtain washing water, and the washing water is used for preparing the sulfuric acid solution in step S1.

[0014] The roasting temperature is 300-600℃, and the roasting time is 6-18h.

[0015] Preferably, in step S3, the organic acid solution comprises an organic acid and water, the organic acid comprises one or more of acetic acid, citric acid, oxalic acid, sulfamic acid, glycolic acid and ethylenediaminetetraacetic acid, the mass content of the organic acid in the organic acid solution is 1-15%, the mass ratio of the organic acid solution to the calcine is 1-20:1, the temperature of the organic acid solution washing is 10-40 DEG C, the time is 0.5-2h, the organic acid solution washing is carried out under stirring, the stirring speed is 200-1500r / min, the number of water washing is 1-5 times, the drying temperature after washing is 100-140 DEG C, and the time is 2-12h.

[0016] Preferably, in step S3, the binder comprises one or more of carboxymethyl cellulose, bentonite, polyvinyl alcohol, aluminum sol, silica sol, silicate cement and aluminate cement, the mass percentage of the binder in the total mass of the purification product and the binder is 5-20%, the extrusion strength of the extrusion molding is 3-15MPa, and the drying temperature of the wet molding body is 60-120 DEG C, and the time is 6-24h.

[0017] The application provides a manganese slag-based VOCs catalyst prepared by the preparation method.

[0018] The application provides application of the manganese slag-based VOCs catalyst in catalytic oxidation removal of VOCs in industrial waste gas.

[0019] The application provides a manganese slag resource utilization method.

[0020] S10, the manganese slag is mixed with a sulfuric acid solution, and after solid-liquid separation, a washing liquid and a washing residue are obtained;

[0021] S20, the washing residue is sequentially subjected to water washing and drying to obtain dry residue material, and the dry residue material is used as raw material for producing building materials;

[0022] S30, the washing liquid and a carbonate aqueous solution are mixed, and then sequentially subjected to a precipitation reaction, standing and solid-liquid separation to obtain a precipitate and a separation liquid;

[0023] S40, the precipitate is calcined to obtain a calcine, the calcine is sequentially washed with an organic acid solution and water, and then dried to obtain a purification product, the purification product, a binder and water are mixed to obtain a mixture material, the mixture material is subjected to extrusion molding to obtain a wet molding body, and the wet molding body is dried to obtain a manganese slag-based VOCs catalyst;

[0024] S50, neutralizing the separated liquid with a sulfuric acid solution until it is neutral, and then sequentially performing evaporation concentration treatment and cooling crystallization treatment to obtain a sulfate product.

[0025] Preferably, in step S20, the washing residue is washed with water to obtain washing water, and the washing water is used to prepare the sulfuric acid solution in step S10;

[0026] In step S50, the evaporation and concentration process also produces cooling water, which is used to prepare the sulfuric acid solution in step S10.

[0027] The present invention provides a preparation method of a VOCs catalyst based on manganese slag, comprising the following steps: S1, mixing manganese slag with a sulfuric acid solution, and obtaining a washing liquid and a washing slag after solid-liquid separation; S2, mixing the washing liquid and a carbonate aqueous solution, sequentially performing a precipitation reaction, standing, and solid-liquid separation to obtain a precipitate and a separated liquid; S3, roasting the precipitate to obtain a roasted product, wherein the roasting atmosphere is air; washing the roasted product with an organic acid solution and water in sequence, and then drying to obtain a purified product; mixing the purified product, a binder, and water to obtain a mixed material; extruding the mixed material to obtain a wet-molded body, and drying the wet-molded body to obtain a VOCs catalyst based on manganese slag. The present invention utilizes manganese slag to prepare a manganese slag-based VOCs catalyst. Metal components such as Mn, Fe, Al, Ca, and Mg and ammonium salt components rich in the manganese slag are washed out with a sulfuric acid solution. SiO2 and some metal oxides that are insoluble in the acid solution still exist in solid form. The present invention uses a sulfuric acid solution for washing. Since sulfuric acid is required in the process of obtaining manganese slag in production, the manganese slag itself contains sulfate ions. The present invention uses a sulfuric acid solution to mix with the manganese slag to wash the manganese slag, thereby avoiding the introduction of new impurities. The present invention obtains, after solid-liquid separation, a washing liquid containing Mn components, Fe components, Al components, Ca components, Mg components, ammonium salts, etc., and a washing residue containing SiO2 and some metal oxides; the washing liquid is mixed with a carbonate aqueous solution to precipitate the metal components therein, and after solid-liquid separation, a precipitate containing metal components such as Mn, Fe, Al, Ca, and Mg and a separated liquid from which the metal components are removed can be obtained; the precipitate containing the metal components is roasted to obtain metal oxides or composite metal oxides, and then washed with an organic acid solution to remove CaO and MgO substances therein; finally, the purified product containing Mn, Fe, Al oxides or composite metal oxides is mixed with a binder, extruded, and dried to obtain a manganese slag-based VOCs catalyst. The present invention utilizes manganese slag to prepare a manganese slag-based VOCs catalyst, realizes resource utilization of metal elements such as Mn, Fe, and Al in the manganese slag, and the prepared manganese slag-based VOCs catalyst has high added value and can be used for catalytic oxidation removal of VOCs in industrial waste gas, thereby reducing VOCs treatment costs.

[0028] The application provides a manganese residue-based VOCs catalyst prepared by the preparation method.

[0029] The application provides a manganese residue resource utilization method. The main components of the separation liquid in which the metal components are removed are sulfates and carbonates, and the carbonates can be converted into sulfates by mixing with a sulfuric acid solution to neutralization. The sulfates such as ammonium sulfate can be obtained by evaporation concentration treatment and cooling crystallization treatment. The manganese residue is washed by the sulfuric acid solution, and the manganese residue itself contains sulfate ions because the process of obtaining the manganese residue needs to use sulfuric acid. The washing by the sulfuric acid solution avoids introducing new impurities and improves the purity of the obtained sulfate byproducts. The manganese residue resource utilization method realizes the resource utilization of Mn, Fe, Al and other metal elements and SiO2, ammonia, ammonium salt in the manganese residue. The manganese residue-based VOCs catalyst has high added value and can be applied to the catalytic oxidation removal of VOCs in industrial waste gas, thereby reducing the VOCs treatment cost. Meanwhile, sulfate byproducts such as ammonium sulfate can also be obtained. BRIEF DESCRIPTION OF DRAWINGS

[0030] Figure 1 A flow chart of the method for treating VOCs by using the manganese residue-based VOCs catalyst prepared by the manganese residue is provided.

[0031] Figure 2 A flow chart of the manganese residue resource utilization method is provided.

[0032] Figure 3 A SEM image of the manganese residue-based VOCs catalyst prepared in Example 1 is provided.

[0033] Figure 4 Toluene catalytic oxidation effect diagrams of VOCs catalysts prepared in different examples and comparative examples are provided, in which the toluene concentration is 1000 ppm, and the space velocity WHSV is 30000 mL / (g.h). DETAILED DESCRIPTION

[0034] The application provides a preparation method of a manganese residue-based VOCs catalyst, which comprises the following steps.

[0035] S1, mixing manganese residue with sulfuric acid solution, and obtaining washing liquid and washing residue after solid-liquid separation;

[0036] S2, sequentially performing precipitation reaction, standing and solid-liquid separation on the washing liquid and aqueous carbonate solution mixture to obtain precipitate and separation liquid;

[0037] S3, roasting the precipitate to obtain roasted material, the atmosphere of the roasting being air; washing the roasted material with organic acid solution and water in sequence, and then drying to obtain purified product; mixing the purified product, binder and water to obtain mixed material; performing extrusion molding on the mixed material to obtain wet molded body, and drying the wet molded body to obtain VOCs catalyst based on manganese residue.

[0038] In the present application, all the preparation raw materials / components are commercially available products well known to those skilled in the art, unless otherwise specified.

[0039] In the present application, the manganese residue is preferably broken manganese residue, and the present application does not have special requirements for the specific implementation of the breaking. The average particle size of the manganese residue is preferably ≤0.5 cm. The mass content of H2SO4 in the sulfuric acid solution is preferably 5-30%, more preferably 10-25%, and can be 10%, 15% or 20% in the examples. The mass ratio of the acid solution to the manganese residue is preferably 3-30:1, more preferably 5-25:1, and can be 25:1 or 20:1 in the examples. The mixing temperature is preferably 20-80°C, more preferably 25-50°C, and can be 70°C in the examples. The mixing time is preferably 1-6h, more preferably 2-5h, and can be 2h in the examples. The mixing is performed under stirring, and the stirring speed is preferably 300-1500r / min, more preferably 400-1000r / min, and can be 500r / min in the examples. In the present application, the solid-liquid separation is preferably filtration.

[0040] After obtaining the washing solution, the present application mixes the washing solution and the aqueous carbonate solution to sequentially carry out a precipitation reaction, standing and solid-liquid separation, to obtain a precipitate and a separation liquid. In the present application, the aqueous carbonate solution contains a water-soluble carbonate. The present application does not have a special requirement for the mass content of the water-soluble carbonate in the aqueous carbonate solution. The water-soluble carbonate is preferably ammonium bicarbonate and / or sodium carbonate. The mass of the water-soluble carbonate in the aqueous carbonate solution is preferably 1.1 times the mass of the water-soluble carbonate required for neutralizing the sulfuric acid solution when mixed with the manganese residue (i.e., the mass of the water-soluble carbonate in the aqueous carbonate solution is 10% more than the mass of H2SO4 in the sulfuric acid solution when mixed with the manganese residue). In the present application, the main role of the water-soluble carbonate is to precipitate the sulfate in the washing solution, and the molar amount of the sulfate in the washing solution should be less than or equal to the molar amount of H2SO4 in the sulfuric acid solution when mixed with the manganese residue. Therefore, the mass of the water-soluble carbonate should be determined according to the mass of the sulfuric acid solution when mixed with the manganese residue. The temperature of the precipitation reaction is preferably 20-50°C, more preferably 25-45°C, and in the examples can be 30°C or 25°C. The time of the precipitation reaction is preferably 0.5-2h, more preferably 1-1.5h, and in the examples can be 2h. The precipitation reaction is preferably carried out under stirring, and the stirring speed is preferably 100-1000r / min, more preferably 200-800r / min, and in the examples can be 300r / min or 400r / min. The temperature of the standing is preferably room temperature. The time of the standing is preferably 6-24h, more preferably 8-12h, and in the examples can be 12h. In the present application, the standing is to age the reaction liquid obtained by the precipitation reaction, to promote the growth of the solid phase in the reaction liquid. In the present application, the solid-liquid separation is preferably filtration.

[0041] After obtaining the precipitate, the present application calcines the precipitate to obtain a calcined product, the atmosphere of the calcination is air; washes the calcined product with an organic acid solution and water in sequence, and then dries to obtain a purified product; mixes the purified product, a binder and water to obtain a mixture; extrusion-molds the mixture to obtain a wet molded body, and dries the wet molded body to obtain a manganese residue-based VOCs catalyst.

[0042] In the present application, the calcination is preferably followed by water washing and drying of the precipitate. The water washing is preferably performed using deionized water. The number of water washing is preferably 3-5 times. The temperature for drying the precipitate is preferably 60-120°C, more preferably 80-100°C, and in the examples can be 70°C; the time is preferably 6-24h, more preferably 8-12h, and in the examples can be 12h. The water washing of the precipitate also produces washing water, which is preferably used for the preparation of the acid solution in the above step.

[0043] In the present application, the calcination is preferably performed at a temperature of 300-600°C, more preferably 400-500°C, and in the examples can be 350°C, 400°C or 500°C; the time is preferably 6-18h, more preferably 10-12h, and in the examples can be 6h, 12h or 8h. The atmosphere for the calcination is air.

[0044] In the present application, the organic acid solution preferably comprises an organic acid and water. The organic acid preferably comprises one or more of acetic acid, citric acid, oxalic acid, sulfamic acid, glycolic acid and ethylenediaminetetraacetic acid. The mass content of the organic acid in the organic acid solution is preferably 1-15%, more preferably 5-10%, and in the examples can be 5%. The mass ratio of the organic acid solution to the calcination product is preferably 1-20:1, more preferably 5-15:1, and in the examples can be 5:1. The temperature for washing with the organic acid solution is preferably 10-40°C, more preferably 20-35°C, and in the examples can be 25°C; the time is preferably 0.5-2h, more preferably 1-1.5h, and in the examples can be 0.5h. The washing with the organic acid solution is preferably performed under stirring, and the stirring speed is preferably 200-1500r / min, more preferably 400-1000r / min, and in the examples can be 300r / min. The number of water washing is preferably 1-5 times, more preferably 3-5 times, and in the examples can be 1 or 3 times. The temperature for drying after washing is preferably 100-140°C, more preferably 110-130°C, and in the examples can be 120°C or 130°C; the time is preferably 2-12h, more preferably 5-10h, and in the examples can be 3h or 6h.

[0045] In the present application, the binder preferably comprises one or more of carboxymethyl cellulose, bentonite, polyvinyl alcohol, aluminum sol, silica sol, silicate cement and aluminate cement, more preferably aluminum sol, silica sol or aluminate cement. The mass of the binder preferably accounts for 5-20% of the total mass of the purification product and the binder, more preferably 10-15%, and in the examples can be 10%, 5% or 15%. The extrusion strength of the extrusion molding preferably is 3-15 MPa, more preferably 5-10 MPa, and in the examples can be 6 MPa, 10 MPa or 8 MPa. The temperature at which the wet molded body is dried preferably is 60-120℃, more preferably 80-100℃, and in the examples can be 70℃; the time preferably is 6-24 h, more preferably 8-12 h, and in the examples can be 12 h.

[0046] The present application provides a manganese slag-based VOCs catalyst prepared by the preparation method of the above technical solution.

[0047] The present application provides an application of the manganese slag-based VOCs catalyst of the above technical solution in catalytic oxidation removal of VOCs in industrial waste gas.

[0048] The present application provides a manganese slag resource utilization method, comprising the following steps:

[0049] S10, mixing manganese slag and sulfuric acid solution, and obtaining washing liquid and washing residue after solid-liquid separation;

[0050] S20, sequentially performing water washing and drying on the washing residue to obtain dry residue material, and using the dry residue material as raw material for producing building materials;

[0051] S30, sequentially performing precipitation reaction, standing and solid-liquid separation on the mixture of the washing liquid and the aqueous carbonate solution to obtain precipitate and separation liquid;

[0052] S40, roasting the precipitate to obtain roasted material, the atmosphere of the roasting being air; sequentially washing the roasted material with organic acid solution and water, and then drying to obtain purification product; mixing the purification product, binder and water to obtain mixed material; performing extrusion molding on the mixed material to obtain wet molded body, and drying the wet molded body to obtain manganese slag-based VOCs catalyst;

[0053] S50, neutralizing the separation liquid to neutral with sulfuric acid solution, and then sequentially performing evaporation concentration treatment and cooling crystallization treatment to obtain sulfate product.

[0054] The step S10, step S30 and step S40 in the manganese slag resource utilization method of the present application are the same as the preparation method of the manganese slag-based VOCs catalyst of the above technical solution, and will not be described here again.

[0055] In the present application, after obtaining the washing residue, the washing residue is sequentially subjected to water washing and drying to obtain dry residue material, which is used as raw material for producing building materials. In the present application, the washing residue is subjected to water washing to further obtain washing water, which is preferably used for preparation of the acid solution in the above step.

[0056] In the present application, after obtaining the separation liquid, the separation liquid is neutralized to neutral with a sulfuric acid solution, and then sequentially subjected to evaporation concentration treatment and cooling crystallization treatment to obtain a sulfate product. In the present application, the content of H2SO4 in the sulfuric acid solution is preferably 1-15 wt%, more preferably 5-10 wt%. The temperature of the cooling crystallization is preferably 10-50°C, more preferably 20-40°C; the time is preferably 5-30 h, more preferably 10-20 h. In the present application, according to the type of water-soluble carbonate used in the above step, the sulfate product is preferably ammonium sulfate and / or sodium sulfate. In the present application, the evaporation concentration treatment further obtains cooling water, which is preferably used for preparation of the acid solution in the above step.

[0057] In order to further illustrate the present application, the technical solutions provided by the present application are described in detail below in conjunction with examples, but they should not be understood as limiting the scope of protection of the present application.

[0058] The following examples are carried out according to the flowcharts shown in Figure 1 and Figure 2 .

[0059] Example 1:

[0060] The present example provides a preparation method of a VOCs catalyst based on manganese slag, and a manganese slag resource utilization method, and the specific steps are as follows:

[0061] (1) The manganese slag is crushed to an average particle size of ≤0.5 cm, and then added to a dilute sulfuric acid aqueous solution with a H2SO4 content of 15 wt% for washing, the mass ratio of the dilute sulfuric acid aqueous solution to the manganese slag is 25:1, the solution temperature during stirring is 70°C, the stirring time is 2 hours, the stirring speed is 500 r / min, and after stirring, solid-liquid separation is performed to obtain a washing liquid and a washing residue.

[0062] (2) The washing residue obtained in step (1) is subjected to water washing and drying to obtain a raw material for producing building materials.

[0063] (3) The washing solution obtained in step (1) is slowly added to an ammonium bicarbonate aqueous solution to perform a precipitation reaction, the mass of ammonium bicarbonate in the ammonium bicarbonate aqueous solution is increased by 10% on the basis of being able to completely consume H2SO4 in the dilute sulfuric acid aqueous solution used in step (1), the reaction temperature is 30°C, the stirring speed is 300 r / min, and the reaction time is 2 hours. After the reaction is completed, the precipitate is allowed to stand at room temperature for 12 hours, and then solid-liquid separation is performed to obtain a precipitate and a separation liquid.

[0064] (4) The precipitate obtained in step (3) is washed with deionized water for 3-5 times to remove adsorbed impurities, and then dried at 70°C for 12 hours, and then calcined at 350°C for 6 hours in an air calcination atmosphere.

[0065] (5) The calcined product obtained in step (4) is washed with a 5wt% acetic acid aqueous solution, the mass ratio of the acetic acid aqueous solution to the calcined product is 5:1, the solution temperature during the stirring process is 25°C, the stirring time is 0.5 hours, the stirring speed is 300 r / min, the acetic acid aqueous solution is washed again with water for 1 time after the washing is completed, and finally the calcined product is dried at 120°C for 3 hours.

[0066] (6) Silicate cement is added to the calcined product obtained after step (5) according to 10% of the total mass (the mass of the calcined product after drying and the silicate cement), mixed uniformly with deionized water, extruded into a shape on an extruder, the forming strength is 6 MPa, and then dried at 70°C for 12 hours to obtain a final manganese slag-based VOCs catalyst. Figure 3 The SEM image of the manganese slag-based VOCs catalyst prepared in Example 1.

[0067] (7) The manganese slag-based VOCs catalyst obtained is loaded into a fixed bed reactor to perform VOCs catalytic oxidation activity evaluation. Figure 4 The results show that the manganese slag-based VOCs catalyst prepared in this example has high activity, and the reaction temperature T 90 is 254°C.

[0068] The VOCs catalytic oxidation activity evaluation method is as follows: the VOCs catalytic oxidation activity evaluation is performed in a fixed bed reactor with an inner diameter of 10 mm, VOCs gas with a toluene concentration of 1000 ppm is prepared by using a gas generator, the air flow rate is set to 100 mL / min, the gas mass space velocity WHSV is 30000 mL / (g·h), the fixed bed reactor is programmed to heat, the gas samples at the inlet and outlet of the reactor are taken, the composition and concentration of the samples are analyzed by using a gas chromatograph, and the VOCs conversion rate is calculated according to the following formula (1):

[0069]

[0070] wherein, C in represents VOCs inlet concentration, C out represents VOCs outlet concentration, both in ppm.

[0071] (8) The separated solution obtained in step (3) is neutralized to neutral with 10wt% dilute sulfuric acid aqueous solution, and then evaporated, concentrated, and cooled to crystallize to obtain an ammonium sulfate product. The cooling crystallization temperature is 40°C, and the time is 12 hours.

[0072] Example 2:

[0073] The embodiment provides a preparation method of a VOCs catalyst based on manganese slag and a manganese slag resource utilization method, and the specific steps are as follows:

[0074] (1) The manganese slag is crushed to an average particle size of less than or equal to 0.5 cm, and then added to a dilute sulfuric acid aqueous solution with a H2SO4 content of 20wt% for washing. The mass ratio of the dilute sulfuric acid aqueous solution to the manganese slag is 20:1, the solution temperature during stirring is 70°C, the stirring time is 2 hours, the stirring speed is 500r / min, and after the stirring is completed, solid-liquid separation is performed to obtain a washing solution and a washing residue.

[0075] (2) The washing residue obtained in step (1) is washed with water and dried to obtain a raw material that can be used for producing building materials.

[0076] (3) The washing solution obtained in step (1) is slowly added to a sodium carbonate aqueous solution for a precipitation reaction. The mass of sodium carbonate in the sodium carbonate aqueous solution is increased by 10% based on the amount of H2SO4 in the dilute sulfuric acid aqueous solution used in step (1) that can be completely consumed, the reaction temperature is 25°C, the stirring speed is 300r / min, and the reaction time is 2 hours. After the reaction is completed, the precipitate is allowed to stand at room temperature for 12 hours, and then solid-liquid separation is performed to obtain a precipitate and a separated solution.

[0077] (4) The precipitate obtained in step (3) is washed with deionized water for 3 to 5 times to remove the adsorbed impurities, and then dried at 70°C for 12 hours, and then calcined at 400°C for 12 hours in an air calcination atmosphere.

[0078] (5) The calcined material obtained in step (4) is washed with a 5wt% citric acid aqueous solution, the mass ratio of the citric acid aqueous solution to the calcined material is 5:1, the solution temperature during stirring is 25°C, the stirring time is 0.5 hours, the stirring speed is 300r / min, the citric acid aqueous solution is washed for 3 times after the washing is completed, and finally the calcined material is dried at 130°C for 6 hours.

[0079] (6) 5% of the total material (the calcined material and the portland cement after drying) by mass was added to the calcined material obtained in step (5) after drying, and mixed with deionized water, and then extrusion-molded on an extruder to have a molding strength of 10 MPa, and then dried at 70°C for 12 hours to obtain a final manganese-slag-based VOCs catalyst.

[0080] (7) The manganese-slag-based VOCs catalyst obtained was loaded into a fixed bed reactor to evaluate the catalytic oxidation activity of VOCs. Figure 4 The results show that the manganese-slag-based VOCs catalyst prepared has high activity, and the reaction temperature T 90 is 263°C at a VOCs conversion rate of 90% for toluene.

[0081] (8) The separated liquid obtained in step (3) was neutralized to neutral with a 10% dilute sulfuric acid solution, and then subjected to evaporation concentration and cooling crystallization treatment to obtain a sodium sulfate product (containing a small amount of ammonium sulfate). The cooling crystallization temperature was 30°C, and the time was 24 hours.

[0082] Example 3:

[0083] This example provides a method for preparing a manganese-slag-based VOCs catalyst and a method for manganese-slag resource utilization, and the specific steps are as follows:

[0084] (1) The manganese slag was crushed to an average particle size of ≤0.5 cm, and then added to a dilute sulfuric acid aqueous solution having a H2SO4 content of 10 wt% for washing. The mass ratio of the dilute sulfuric acid aqueous solution to the manganese slag was 20:1, the solution temperature during stirring was 70°C, the stirring time was 2 hours, the stirring speed was 500 r / min, and after the stirring was completed, solid-liquid separation was performed to obtain a washing liquid and a washing residue.

[0085] (2) The washing residue obtained in step (1) was washed with water and dried to obtain a raw material that can be used for producing building materials.

[0086] (3) The washing liquid obtained in step (1) was slowly added to an ammonium bicarbonate aqueous solution for a precipitation reaction. The mass of ammonium bicarbonate in the ammonium bicarbonate aqueous solution was increased by 10% based on the amount of H2SO4 in the dilute sulfuric acid aqueous solution used in step (1) that could be completely consumed. The reaction temperature was 30°C, the stirring speed was 400 r / min, and the reaction time was 2 hours. After the reaction was completed, the precipitate was allowed to stand at room temperature for 12 hours, and then subjected to solid-liquid separation to obtain a precipitate and a separated liquid.

[0087] (4) The precipitate obtained in step (3) was washed with deionized water for 3 to 5 times to remove the adsorbed impurities, and then dried at 70°C for 12 hours, and then calcined at 500°C for 8 hours in an air calcination atmosphere.

[0088] (5) Washing the calcined substance obtained in step (4) with 10 wt% acetic acid aqueous solution, the mass ratio of acetic acid aqueous solution to calcined substance being 5:1, the solution temperature during stirring being 25°C, the stirring time being 0.5 hour, the stirring speed being 300 r / min, and washing with water once after the acetic acid washing, and finally drying the calcined substance at 120°C for 3 hours.

[0089] (6) Adding aluminum sol to the calcined substance obtained in step (5) according to 15% of the total mass (the mass of the calcined substance after drying and the aluminum sol), mixing uniformly with deionized water, extruding into shape on an extruder, the forming strength being 8 MPa, and then drying at 70°C for 12 hours to obtain the final manganese slag-based VOCs catalyst.

[0090] (7) Loading the obtained manganese slag-based VOCs catalyst into a fixed bed reactor to evaluate the catalytic oxidation activity of VOCs. Figure 4 The results show that the prepared manganese slag-based VOCs catalyst has high activity, and the reaction temperature T 90 is 268°C when the VOCs conversion rate containing toluene is 90%.

[0091] (8) Neutralizing the separated liquid obtained in step (3) with 10% dilute sulfuric acid solution, and then performing evaporation concentration, cooling crystallization treatment to obtain an ammonium sulfate product. The cooling crystallization temperature is 40°C, and the time is 12 hours.

[0092] Comparative Example 1

[0093] This comparative example provides a manganese slag resource utilization method, and a manganese slag-based VOCs catalyst is also prepared, and the specific steps are as follows:

[0094] (1) Crushing the manganese slag to an average particle size of ≤0.5 cm, and adding to a dilute sulfuric acid solution with a H2SO4 content of 15 wt% for washing, the mass ratio of the dilute sulfuric acid aqueous solution to the manganese slag being 25:1, the solution temperature during stirring being 70°C, the stirring time being 2 hours, the stirring speed being 500 r / min, and after the stirring is completed, the solid-liquid separation is performed to obtain a washing liquid and a washing residue.

[0095] (2) Washing and drying the washing residue obtained in step (1) for standby use.

[0096] (3) Slowly adding the washing liquid obtained in step (1) to an ammonium bicarbonate aqueous solution for a precipitation reaction, the mass of ammonium bicarbonate in the ammonium bicarbonate aqueous solution being 10% more than that required to completely consume the H2SO4 in the dilute sulfuric acid aqueous solution used in step (1), the reaction temperature being 30°C, the stirring speed being 300 r / min, and the reaction time being 2 hours. After the reaction is completed, the precipitation is allowed to stand for 12 hours, and after the solid-liquid separation, a precipitate and a separated liquid are obtained.

[0097] (4) The precipitate obtained in step (3) is washed with deionized water for 3 to 5 times to remove the adsorbed impurities, and after the washing is completed, the precipitate is dried at 70°C for 12 hours.

[0098] (5) The dried washed residue and precipitate obtained in steps (2) and (4) are mixed, 10% of the total mass (dried washed residue, precipitate and Portland cement) of the obtained mixture is added with Portland cement, and the mixture is mixed with an appropriate amount of deionized water, and then extruded into a shape on an extruder, the molding strength is 6 MPa, and then dried at 70°C for 12 hours, and then calcined at 350°C for 6 hours in an air calcination atmosphere to obtain a calcined product.

[0099] (6) The calcined product obtained in step (5) is washed with 5% acetic acid aqueous solution, the mass ratio of acetic acid aqueous solution to calcined product is 5:1, the solution temperature during the stirring process is 25°C, the stirring time is 0.5 hours, the stirring speed is 300 r / min, and after the acetic acid solution washing is completed, the calcined product is dried at 120°C for 3 hours to obtain the final manganese slag-based VOCs catalyst.

[0100] (7) The obtained manganese slag-based VOCs catalyst is loaded into a fixed bed reactor to evaluate the catalytic oxidation activity of VOCs. The results show that: when the VOCs conversion rate containing toluene is 90%, the reaction temperature T 90 is 377°C.

[0101] (8) The separated liquid obtained in step (3) is neutralized to neutral with 10% dilute sulfuric acid aqueous solution, and then evaporated, concentrated, and cooled to crystallize to obtain an ammonium sulfate product. The cooling crystallization temperature is 40°C, and the time is 12 hours.

[0102] In Comparative Example 1, the washed residue after pickling is added to the catalyst, which is intended to play a partial carrier effect, but from the results of activity evaluation Figure 4 , it can be seen that due to the absence of active components in the washed residue, the activity of the final shaped catalyst decreases significantly, and when the VOCs conversion rate is 90%, the reaction temperature T 90 increases from 254°C to 377°C, and the catalytic effect is poor.

[0103] Comparative Example 2:

[0104] This comparative example is basically the same as Example 3, and the only difference from Example 3 is that:

[0105] In step (5), 10% hydrochloric acid solution is used instead of 10% acetic acid aqueous solution to wash the calcined product obtained in step (4).

[0106] The manganese slag-based VOCs catalyst obtained in Comparative Example 2 is loaded into a fixed bed reactor to evaluate the catalytic oxidation activity of VOCs. Figure 4The results show that the reaction temperature T at which the VOCs containing toluene have a conversion rate of 90% is 330°C. 90 The results show that the reaction temperature T at which the VOCs containing toluene have a conversion rate of 90% is 330°C.

[0107] In the comparative example 2, hydrochloric acid is used instead of acetic acid to wash the calcined substance. The results of the activity evaluation show that the catalyst activity is significantly reduced. Since hydrochloric acid is a strong inorganic acid, it can react with the active components in the oxide state in addition to the components such as CaO and MgO in the calcined substance, resulting in a decrease in the active components, which is not conducive to the catalytic oxidation reaction.

[0108] In the comparative example 3,

[0109] The comparative example is basically the same as the example 3, and the only difference from the example 3 is that:

[0110] In the step (4), the adjustment is to first calcine at 500°C for 6 hours in an air calcination atmosphere and then calcine at 500°C for 2 hours in a nitrogen calcination atmosphere.

[0111] The VOCs catalyst obtained in the comparative example 3 is loaded into a fixed bed reactor for evaluation of the catalytic oxidation activity of VOCs. Figure 4 The results show that the reaction temperature T at which the VOCs containing toluene have a conversion rate of 90% is 330°C. 90 The results show that the reaction temperature T at which the VOCs containing toluene have a conversion rate of 90% is 330°C.

[0112] In the comparative example 3, the precipitate is calcined in an air calcination atmosphere and then in a nitrogen calcination atmosphere. The results of the activity evaluation show that the catalyst activity is significantly reduced, which indicates that the nitrogen calcination atmosphere is not conducive to the generation of active components, and is an unfavorable factor for the preparation of catalytic oxidation catalysts.

[0113] From the above examples, the manganese slag resource utilization method provided by the application can wash out the metal components and ammonium salt components rich in Mn, Fe, Al, Ca, Mg and the like in the manganese slag by using dilute sulfuric acid, and the SiO2 and part of the metal oxides insoluble in dilute sulfuric acid still exist in solid form. After solid-liquid separation, a washing liquid containing Mn, Fe, Al, Ca, Mg, ammonium salt and the like and a washing residue containing SiO2 and part of the metal oxides are obtained. The washing residue is washed with water and dried, and then used to produce cement, concrete, roadbed and other building materials. The washing liquid is slowly added to an aqueous carbonate solution, and the metal components therein can be precipitated. After solid-liquid separation, a precipitate containing metal components such as Mn, Fe, Al, Ca and Mg and a separation liquid from which the metal components are removed are obtained. The precipitate containing metal components is calcined to obtain metal oxides or composite metal oxides, and then washed with an organic acid solution to remove CaO, MgO and the like. Finally, the metal oxides or composite metal oxides containing Mn, Fe and Al are mixed with a binder, extruded, dried and then a VOCs catalyst is obtained. The main components in the separation liquid from which the metal components are removed are sulfates and carbonates. By adding dilute sulfuric acid to neutralize the solution, the carbonates in the solution can be converted into sulfates. After evaporation, concentration, cooling and crystallization, ammonium sulfate and other sulfate products are obtained. The manganese slag resource utilization method provided by the application realizes the resource utilization of metal elements such as Mn, Fe and Al and SiO2, ammonia and ammonium salt in the manganese slag. The VOCs catalyst prepared has high added value and can be applied to the catalytic oxidation and removal of VOCs in industrial waste gas, thereby reducing the VOCs treatment cost. At the same time, ammonium sulfate and other sulfate by-products can also be obtained.

[0114] Although the above examples have made a detailed description of the application, it is only a part of the embodiments of the application, not all the embodiments, and other embodiments can be obtained under the premise of no creativity according to the present embodiments, which all belong to the protection scope of the application.

Claims

1. A method for preparing a VOCs catalyst based on manganese slag, characterized in that: The following steps are involved: S1, mixing manganese slag with sulfuric acid solution, and obtaining washing liquid and washing slag after solid-liquid separation; S2, mixing the washing liquid and the carbonate aqueous solution, sequentially performing precipitation reaction, standing and solid-liquid separation to obtain a precipitate and a separated liquid; S3. calcining the precipitate to obtain a calcined product, wherein the calcination atmosphere is air; washing the calcined product with an organic acid solution and water in sequence, and then drying to obtain a purified product; mixing the purified product, a binder, and water to obtain a mixed material; extruding the mixed material to obtain a wet molded body, and drying the wet molded body to obtain a manganese slag-based VOCs catalyst.

2. The preparation method according to claim 1, characterized in that In step S1, the manganese slag is crushed manganese slag, and the average particle size of the manganese slag is ≤0.5 cm; the mass content of H2SO4 in the sulfuric acid solution is 5-30%; the mass ratio of the sulfuric acid solution to the manganese slag is 3-30:1; the mixing temperature is 20-80°C, the time is 1-6 hours, and the mixing is carried out under stirring conditions, and the stirring speed is 300-1500 r / min.

3. The preparation method according to claim 1, characterized in that In step S2, the carbonate aqueous solution contains water-soluble carbonate, and the mass of the water-soluble carbonate in the carbonate aqueous solution is 1.1 times the mass of the water-soluble carbonate required to neutralize the sulfuric acid solution in step S1; the temperature of the precipitation reaction is 20-50°C, the time is 0.5-2h, the precipitation reaction is carried out under stirring conditions, and the stirring speed is 100-1000r / min; the standing time is 6-24h.

4. The preparation method according to claim 1, characterized in that In step S3, before the calcination, the precipitate is washed with water and dried in sequence, the drying temperature of the precipitate is 60-120° C., and the drying time is 6-24 hours; the precipitate is washed with water to obtain washing water, and the washing water is used to prepare the sulfuric acid solution in step S1; The calcination temperature is 300-600° C., and the calcination time is 6-18 hours.

5. The preparation method according to claim 1, characterized in that In step S3, the organic acid solution includes an organic acid and water, the organic acid includes one or more of acetic acid, citric acid, oxalic acid, sulfamic acid, glycolic acid and ethylenediaminetetraacetic acid, and the mass content of the organic acid in the organic acid solution is 1 to 15%; the mass ratio of the organic acid solution to the calcined product is 1 to 20:1, the temperature of the organic acid solution washing is 10 to 40° C., the time is 0.5 to 2 hours, the organic acid solution washing is carried out under stirring, the stirring speed is 200 to 1500 r / min, and the number of water washings is 1 to 5 times; the temperature of drying after washing is 100 to 140° C., and the time is 2 to 12 hours.

6. The preparation method according to claim 1, characterized in that In step S3: the binder includes one or more of carboxymethyl cellulose, bentonite, polyvinyl alcohol, aluminum sol, silica sol, silicate cement and aluminate cement, and the mass of the binder accounts for 5 to 20% of the total mass of the purified product and the binder; the extrusion strength of the extrusion molding is 3 to 15 MPa, and the temperature of the wet molded body is dried at 60 to 120°C for 6 to 24 hours.

7. A VOCs catalyst based on manganese slag obtained by the preparation method according to any one of claims 1 to 6.

8. Use of the VOCs catalyst based on manganese slag according to claim 7 in the catalytic oxidation removal of VOCs in industrial waste gas.

9. A method for resource utilization of manganese slag, characterized in that: The following steps are involved: S10, mixing manganese slag with sulfuric acid solution, and obtaining washing liquid and washing slag after solid-liquid separation; S20, washing and drying the washed residue in sequence to obtain a dry residue material, and using the dry residue material as a raw material for producing building materials; S30, mixing the washing liquid and the carbonate aqueous solution, sequentially performing precipitation reaction, standing, and solid-liquid separation to obtain a precipitate and a separated liquid; S40, calcining the precipitate to obtain a calcined product, wherein the calcination atmosphere is air; washing the calcined product with an organic acid solution and water in sequence, and then drying to obtain a purified product; mixing the purified product, a binder, and water to obtain a mixed material; extruding the mixed material to obtain a wet molded body, and drying the wet molded body to obtain a manganese slag-based VOCs catalyst; S50, neutralizing the separated liquid with a sulfuric acid solution until it is neutral, and then sequentially performing evaporation concentration treatment and cooling crystallization treatment to obtain a sulfate product.

10. The method for resource utilization of manganese slag according to claim 9, characterized in that: In step S20, the washing residue is washed with water to obtain washing water, which is used to prepare the sulfuric acid solution in step S10; In step S50, the evaporation and concentration process also produces cooling water, which is used to prepare the sulfuric acid solution in step S10.

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