Method for preparing denitration catalyst based on vanadium slag

Abstract

The invention relates to the field of comprehensive utilization of resources and treatment of waste with waste, in particular to a method for preparing a denitration catalyst based on vanadium slag. The method comprises the following steps: roasting the vanadium slag to obtain clinker, adding the clinker into a leaching agent, leaching, and filtering to obtain filtrate 1 and slag 1; cooling and crystallizing the filtrate 1 to obtain ammonium metavanadate crystals; adding the residue 1 into a sulfuric acid solution, leaching, and filtering to obtain filtrate 2; adding a potassium ferrocyanide solution into the filtrate 2, reacting, and filtering to obtain filtrate 3 and a precipitate 1; adding the precipitate 1 into an acid solution for reaction, and filtering to obtain filtrate 4; adding an alkali solution into the filtrate 4, reacting, and filtering to obtain ferric hydroxide precipitate; adding an oxidizing agent solution into the filtrate 3 for reaction to obtain manganese dioxide; uniformly mixing the ammonium metavanadate crystal, the ferric hydroxide precipitate and manganese dioxide, and roasting to obtain the denitration catalyst. The method disclosed by the invention has the dual advantages of high-value utilization of the metallurgical solid waste and dual-carbon emission reduction.

Description

Technical Field

[0001] The present invention relates to the field of comprehensive resource utilization and waste treatment, and in particular to a method for preparing a denitration catalyst based on vanadium slag. Background Art

[0002] The control of nitrogen oxides in industrial flue gas and automobile exhaust has always been a key focus of the country. x It can easily cause acid rain and react with volatile organic compounds to produce photochemical smog, which is harmful to the respiratory system of organisms. x It is a precursor to ground-level ozone, which has a negative impact on human health and the ecosystem. Therefore, the reduction of nitrogen oxides is urgent. Currently, the selective reduction of ammonia is the mainstream denitrification technology, and a denitrification catalyst is needed to promote NO x The catalyst's catalytic performance is the core of the process, reacting with the reducing agent and converting it into harmless nitrogen and water, thereby significantly reducing pollutant emissions.

[0003] Using solid waste as raw material to prepare catalysts is a typical "waste-to-waste" strategy that has garnered widespread attention in recent years. Vanadium slag is a vanadium-, iron-, and manganese-rich byproduct produced during the smelting of vanadium-titanium magnetite in blast furnaces and converters. Large-scale storage of vanadium slag consumes land resources. Furthermore, vanadium slag contains various heavy metal ions. If not treated during storage, they can leach into soil and water bodies through rainwater, causing environmental pollution.

[0004] If a denitrification catalyst can be prepared using vanadium slag as raw material, it will be of great significance for the comprehensive utilization of resources and waste treatment. Summary of the Invention

[0005] The purpose of the present invention is to achieve high-value utilization of vanadium slag, reflecting a typical coupling strategy that integrates nitrogen pollutant emission reduction and solid waste treatment. The vanadium, iron and manganese elements in the vanadium slag are extracted in sequence and used to prepare a denitrification catalyst. The vanadium slag source catalyst has low cost, simple preparation process, excellent catalytic performance and stable sulfur and water resistance, and has significant economic and large-scale application potential in nitrogen oxide emission reduction. Through the high-value utilization of vanadium slag, deep NOx removal and solid waste resource regeneration are simultaneously achieved, forming a synergistic and effective path for nitrogen pollution control and metallurgical solid waste management.

[0006] To achieve the above object, the present invention provides the following solutions:

[0007] One of the technical solutions of the present invention is a method for preparing a denitration catalyst based on vanadium slag, comprising the following steps:

[0008] Step 1, roasting vanadium slag to obtain clinker; adding the clinker to a leaching agent for leaching and filtering to obtain filtrate 1 and slag 1; cooling and crystallizing the filtrate 1 to obtain ammonium metavanadate crystals;

[0009] Step 2, the residue 1 is added to a sulfuric acid solution for leaching and then filtered to obtain a filtrate 2; potassium ferrocyanide solution is added to the filtrate 2, reacted, and then filtered to obtain a filtrate 3 and a precipitate 1;

[0010] Step 3, adding the precipitate 1 to an acid solution, reacting the solution, and filtering the solution to obtain a filtrate 4; adding an alkaline solution to the filtrate 4, reacting the solution, and filtering the solution to obtain an iron hydroxide precipitate;

[0011] Step 4, adding an oxidant solution to the filtrate 3 to react to obtain manganese dioxide;

[0012] Step 5, mixing the ammonium metavanadate crystals, the ferric hydroxide precipitate and the manganese dioxide and then calcining them to obtain the denitration catalyst;

[0013] Among them, step 3 and step 4 are not performed in any particular order.

[0014] The second technical solution of the present invention is a denitration catalyst prepared according to the above method.

[0015] The third technical solution of the present invention is the use of the above-mentioned denitration catalyst in removing nitrogen oxides.

[0016] The present invention discloses the following technical effects:

[0017] The vanadium, iron and manganese elements rich in vanadium slag are extremely compatible with the active components of the denitrification catalyst. The present invention extracts vanadium, iron and manganese elements from vanadium slag to prepare a denitrification catalyst, which has the dual functions of resource utilization of metallurgical solid waste and denitrification of sintering flue gas, and has significant technical advantages and broad application prospects.

[0018] The method of the present invention has the advantages of high production efficiency and suitability for industrial promotion.

[0019] The catalyst prepared by the method of the present invention has a high conversion rate, good selectivity, and low raw material cost, and has the dual advantages of high-value utilization of metallurgical solid waste and "dual carbon" emission reduction. DETAILED DESCRIPTION

[0020] Various exemplary embodiments of the present invention will now be described in detail. This detailed description should not be considered as limiting the present invention, but rather as a more detailed description of certain aspects, features, and embodiments of the present invention.

[0021] It should be understood that the terms described herein are intended only to describe particular embodiments and are not intended to limit the present invention. In addition, for numerical ranges herein, it should be understood that each intermediate value between the upper and lower limits of the range is also specifically disclosed. The intermediate value within any stated value or stated range, and each smaller range between any other stated value or intermediate value within the stated range, is also encompassed within the present invention. The upper and lower limits of these smaller ranges may be independently included or excluded within the scope.

[0022] Unless otherwise indicated, all technical and scientific terms used herein have the same meaning as commonly understood by those skilled in the art. Although only preferred methods and materials are described herein, any methods and materials similar or equivalent to those described herein may also be used in the practice or testing of the present invention. All documents mentioned in this specification are incorporated by reference to disclose and describe the methods and / or materials associated with the documents. In the event of any conflict with any incorporated document, the contents of this specification shall prevail.

[0023] It will be apparent to those skilled in the art that various modifications and variations may be made to the specific embodiments described herein without departing from the scope or spirit of the invention. Other embodiments will be apparent to those skilled in the art from the description of the invention. The description and examples are intended to be exemplary only.

[0024] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0025] Unless otherwise specified, the "%" in the present invention refers to mass percentage.

[0026] The "room temperature" mentioned in the present invention, unless otherwise specified, refers to 20-30°C.

[0027] A first aspect of the present invention provides a method for preparing a denitration catalyst based on vanadium slag, comprising the following steps:

[0028] Step 1, roasting vanadium slag to obtain clinker; adding the clinker to a leaching agent for leaching and filtering to obtain filtrate 1 and slag 1; cooling and crystallizing the filtrate 1 to obtain ammonium metavanadate crystals;

[0029] Step 2, the residue 1 is added to a sulfuric acid solution for leaching and then filtered to obtain a filtrate 2; potassium ferrocyanide solution is added to the filtrate 2, reacted, and then filtered to obtain a filtrate 3 and a precipitate 1;

[0030] Step 3, adding the precipitate 1 to an acid solution, reacting the solution, and filtering the solution to obtain a filtrate 4; adding an alkaline solution to the filtrate 4, reacting the solution, and filtering the solution to obtain an iron hydroxide precipitate;

[0031] Step 4, adding an oxidant solution to the filtrate 3 to react to obtain manganese dioxide;

[0032] Step 5, mixing the ammonium metavanadate crystals, the ferric hydroxide precipitate and the manganese dioxide and then calcining them to obtain the denitration catalyst;

[0033] Among them, step 3 and step 4 are not performed in any particular order.

[0034] In a preferred embodiment of the present invention, in step 1, the roasting conditions are set as follows: in an atmosphere with an oxygen content of 5-30% and nitrogen as the balance gas, the temperature is raised to 850-900° C. at a rate of 2-10° C. / min and calcined for 100-120 minutes; the particle size of the vanadium slag is not greater than 300 mesh; the leaching agent is an ammonium bicarbonate solution with a mass concentration of 20%-50%; and the solid-liquid ratio of the clinker to the leaching agent is 1 g:(4-8) mL.

[0035] In a preferred embodiment of the present invention, in step 1, the leaching temperature is 40-60° C., and the leaching time is 100-180 min.

[0036] In step 1, stirring is performed during the leaching process. The present invention does not impose any particular limitation on the stirring speed, and a conventional stirring speed used by those skilled in the art may be used, such as 300-1200 r / min.

[0037] In a preferred embodiment of the present invention, in step 2, the mass concentration of the sulfuric acid solution is 10% to 40%; the solid-liquid ratio of the slag 1 to the sulfuric acid solution is 1 g: (10 to 30) mL; the leaching temperature is 60-80° C., and the leaching time is 120 to 300 min; the mass concentration of the potassium ferrocyanide solution is 20% to 60%; and the volume ratio of the potassium ferrocyanide solution to the filtrate 2 is 1: (6 to 10).

[0038] In step 2, stirring is performed during the leaching process. The present invention does not impose any particular limitation on the stirring speed, and a conventional stirring speed used by those skilled in the art may be used, such as 300-1200 r / min.

[0039] In a preferred embodiment of the present invention, in step 3, the acid solution is a hydrochloric acid solution with a mass concentration of 30% to 60%; the solid-liquid ratio of the precipitate 1 to the acid solution is 1 g: (30 to 40) mL;

[0040] The precipitate 1 is added to the acid solution and the reaction time is 10 to 30 minutes;

[0041] The alkaline solution is a sodium hydroxide solution with a mass concentration of 10-40%;

[0042] The volume ratio of the alkaline solution to the filtrate 4 is 1:(5-10).

[0043] The alkaline solution is added to the filtrate 4 and the reaction time is 20 to 40 minutes.

[0044] In a preferred embodiment of the present invention, in step 4, the oxidant solution is a potassium permanganate solution with a mass concentration of 10-40%; the volume ratio of the oxidant solution to the filtrate 3 is 1:(10-15); and the reaction time is 10-30 minutes.

[0045] In a preferred embodiment of the present invention, in step 5, the calcination conditions are set as follows: in an air atmosphere, heating to 400-500° C. at a rate of 2-10° C. / min and calcining for 3-6 hours.

[0046] In a preferred embodiment of the present invention, in step 5, the mass ratio of ammonium metavanadate crystals to ferric hydroxide precipitate and manganese dioxide is (1-25):(1-20):(55-98).

[0047] A second aspect of the present invention provides a denitration catalyst prepared according to the above method.

[0048] A third aspect of the present invention provides use of the above-mentioned denitration catalyst in removing nitrogen oxides.

[0049] Unless otherwise specified, the technical solutions described in the present invention are all conventional solutions in the field, and the reagents or raw materials used, unless otherwise specified, are purchased from commercial channels or have been disclosed.

[0050] The composition of the vanadium slag used in the embodiment of the present invention is: SiO2: 19%, Fe2O3: 46%, MnO2: 18%, V2O5: 14%, and other inevitable impurities: 3%.

[0051] In the present invention, the calculation formula of nitrogen oxide removal rate is: Test method: 0.3g of catalyst with a particle size of 50-100 mesh was placed in a fixed bed reactor to evaluate the NH3-SCR performance. The simulated flue gas contained 500ppm NH3, 500ppm NO, and 5vol% O2 at a total flow rate of 300mL / min. An infrared gas detector (Gasmet FTIR DX-4000) was used to measure the outlet NO. x concentration.

[0052] The technical solutions provided by the present invention are described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0053] Example 1

[0054] After grinding the vanadium slag through a 200-mesh sieve, the temperature was raised from room temperature to 900°C in a muffle furnace at a rate of 5°C / min, roasted for 120 minutes, and cooled to room temperature to obtain clinker, which was then ground through a 200-mesh sieve. 40 g of the clinker was added to a leaching agent (40% ammonium bicarbonate solution) at a solid-to-liquid ratio of 1:6 (g / mL). The mixture was stirred and leached at 55°C for 150 minutes, filtered, and obtained filtrate 1 and slag 1. Filtrate 1 was cooled and crystallized to obtain ammonium metavanadate crystals. Slag 1 was ground through a 200-mesh sieve. 30 g of the ground slag 1 was added to a 20% dilute sulfuric acid solution at a solid-to-liquid ratio of 1:30 (g / mL) and stirred and leached at 70°C for 300 minutes. The mixture was filtered to obtain filtrate 2. 30% potassium ferrocyanide (K4[Fe(CN)6] . 3H2O) solution was stirred for 10 minutes. The volume ratio of potassium ferrocyanide solution to filtrate 2 was 1:7. The mixture was filtered to obtain filtrate 3 and precipitate 1. Precipitate 1 was added to a 50% hydrochloric acid solution at a solid-to-liquid ratio of 1 g:35 ml, stirred for 30 minutes, and filtered to obtain filtrate 4. A 20% sodium hydroxide solution was added to filtrate 4, stirred for 10 minutes. The volume ratio of sodium hydroxide solution to filtrate 4 was 1:6. The mixture was filtered to obtain a ferric hydroxide precipitate. A 40% potassium permanganate solution was added to filtrate 3, stirred for 10 minutes. The volume ratio of potassium permanganate solution to filtrate 3 was 1:10. The mixture was filtered to obtain manganese dioxide.

[0055] 0.68g of ammonium metavanadate crystals, 3.05g of manganese dioxide, and 6.26g of ferric hydroxide were weighed and mechanically ground to mix thoroughly. The mixture was then heated in a muffle furnace from room temperature to 500°C at a rate of 7°C / min, calcined for 240 minutes, and then cooled to room temperature to produce a vanadium-iron-manganese denitration catalyst. The vanadium-iron-manganese denitration catalyst prepared in this example achieved a maximum nitrogen oxide removal rate of 96.1% at 180°C.

[0056] Example 2

[0057] The only difference from Example 1 is that when preparing the vanadium iron manganese denitration catalyst, the amount of manganese dioxide added is 3.55 g; the remaining steps and parameters are the same as in Example 1.

[0058] The nitrogen oxide removal rate of the vanadium-iron-manganese denitration catalyst prepared in this example reaches a maximum of 98.3% at 180°C.

[0059] Example 3

[0060] The only difference from Example 1 is that when preparing the vanadium iron manganese denitration catalyst, the amount of manganese dioxide added is 4.04 g; the remaining steps and parameters are the same as in Example 1.

[0061] The nitrogen oxide removal rate of the vanadium iron manganese denitration catalyst prepared in this example reaches a maximum of 95.6% at 190°C.

[0062] The embodiments described above are merely descriptions of preferred embodiments of the present invention and are not intended to limit the scope of the present invention. Without departing from the spirit of the present invention, various modifications and improvements made to the technical solutions of the present invention by persons skilled in the art should fall within the scope of protection defined by the claims of the present invention.

Claims

1. A method for preparing a denitration catalyst based on vanadium slag, characterized in that: The following steps are involved: Step 1, roasting vanadium slag to obtain clinker; adding the clinker to a leaching agent for leaching and filtering to obtain filtrate 1 and slag 1; cooling and crystallizing the filtrate 1 to obtain ammonium metavanadate crystals; Step 2, the residue 1 is added to a sulfuric acid solution for leaching and then filtered to obtain a filtrate 2; potassium ferrocyanide solution is added to the filtrate 2, reacted, and then filtered to obtain a filtrate 3 and a precipitate 1; Step 3, adding the precipitate 1 to an acid solution, reacting the solution, and filtering the solution to obtain a filtrate 4; adding an alkaline solution to the filtrate 4, reacting the solution, and filtering the solution to obtain an iron hydroxide precipitate; Step 4, adding an oxidant solution to the filtrate 3 to react to obtain manganese dioxide; Step 5, mixing the ammonium metavanadate crystals, the ferric hydroxide precipitate and the manganese dioxide and then calcining them to obtain the denitration catalyst; Among them, step 3 and step 4 are not performed in any particular order.

2. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 1, the roasting conditions are set as follows: in an atmosphere with an oxygen content of 5-30% and nitrogen as the balance gas, the temperature is raised to 850-900° C. at a rate of 2-10° C. / min and calcined for 100-120 minutes; the particle size of the vanadium slag is not greater than 300 mesh; the leaching agent is an ammonium bicarbonate solution with a mass concentration of 20%-50%; and the solid-liquid ratio of the clinker to the leaching agent is 1 g: (4-8) mL.

3. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 1, the leaching temperature is 40-60° C., and the leaching time is 100-180 minutes.

4. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 2, the mass concentration of the sulfuric acid solution is 10% to 40%; the solid-liquid ratio of the slag 1 to the sulfuric acid solution is 1 g: (10 to 30) mL; the leaching temperature is 60-80° C., and the leaching time is 120 to 300 min; the mass concentration of the potassium ferrocyanide solution is 20% to 60%; and the volume ratio of the potassium ferrocyanide solution to the filtrate 2 is 1: (6 to 10).

5. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 3, the acid solution is a hydrochloric acid solution with a mass concentration of 30% to 60%; the solid-liquid ratio of the precipitate 1 to the acid solution is 1 g: (30 to 40) mL; The precipitate 1 is added to the acid solution and the reaction time is 10 to 30 minutes; The alkaline solution is a sodium hydroxide solution with a mass concentration of 10-40%; The volume ratio of the alkaline solution to the filtrate 4 is 1:(5-10); The alkaline solution is added to the filtrate 4 and the reaction time is 20 to 40 minutes.

6. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 4, the oxidant solution is a potassium permanganate solution with a mass concentration of 10-40%; the volume ratio of the oxidant solution to the filtrate 3 is 1:(10-15); and the reaction time is 10-30 minutes.

7. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 5, the calcination conditions are set as follows: in an air atmosphere, heating to 400-500° C. at a rate of 2-10° C. / min and calcining for 3-6 hours.

8. The method for preparing a denitration catalyst based on vanadium slag according to claim 1, characterized in that: In step 5, the mass ratio of ammonium metavanadate crystals to ferric hydroxide precipitate and manganese dioxide is (1-25):(1-20):(55-98).

9. A denitration catalyst prepared according to the method according to any one of claims 1 to 8.

10. Use of the denitration catalyst according to claim 9 in removing nitrogen oxides.