Preparation method, product and application of nh3-scr catalyst

Abstract

The application provides a preparation method, product and application of an NH3-SCR catalyst, and belongs to the technical field of catalyst preparation. The preparation method comprises the following steps: grinding, sieving and drying electrolytic manganese residue to obtain electrolytic manganese residue in a raw state; calcining the electrolytic manganese residue in the raw state to obtain a calcined electrolytic manganese residue sample; immersing the electrolytic manganese residue in an acid solution to collect a leaching solution; and immersing the calcined electrolytic manganese residue sample in the leaching solution and then drying to obtain an NH3-SCR catalyst. The method provided by the application uses dilute nitric acid to activate and self-modify electrolytic manganese residue, effectively improves the denitration performance of the electrolytic manganese residue, and the catalyst has a denitration efficiency of more than 77% in a temperature range of 25-150 DEG C and a denitration efficiency of 100% in a temperature range of 150-450 DEG C. Meanwhile, the problems of high cost of existing bulk solid waste treatment technology and poor thermal stability of commercial catalysts are solved, and the purpose of waste treatment by waste is achieved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of catalyst preparation, in particular to a preparation method, product and application of an NH3-SCR catalyst. BACKGROUND

[0002] At present, the catalyst gradually applied to the selective catalytic reduction (NH3-SCR) of flue gas in thermal power generation is a V2O5-WO3 / TiO2 series catalyst, which has the characteristics of high denitration efficiency, but high denitration temperature, high denitration cost and poor thermal stability of the catalyst, which limits its application in low-temperature flue gas industries such as glass, rubber and steel. With the rapid development of the electrolytic manganese industry, the anode mud generated near the electrolysis anode in the electrolytic manganese process, after solid-liquid separation and pressure filtration, produces electrolytic manganese slag, and electrolytic manganese production enterprises must use a large amount of special sites to store these solid waste, which not only increases the production cost of the enterprise, but also occupies a large amount of land resources, and at the same time, the leachate generated during the storage process contains a large amount of ammonia nitrogen elements, which seriously pollutes the environment and affects human health. Therefore, using electrolytic manganese slag to prepare a catalyst for catalytic reduction (NH3-SCR) denitration can make waste useful and realize waste control with waste, which has important application value. SUMMARY

[0003] Based on the above, the present application aims to provide a preparation method, product and application of an NH3-SCR catalyst, which uses dilute nitric acid activation and self-modification of electrolytic manganese slag to effectively improve the denitration performance of the electrolytic manganese slag, and at the same time solves the problems of high cost of existing bulk solid waste treatment technology and poor thermal stability of commercial catalysts, achieving the purpose of waste control with waste.

[0004] In order to achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0005] The present application provides a preparation method of an NH3-SCR catalyst in a first aspect, comprising the following steps:

[0006] The electrolytic manganese slag is ground, sieved and then dried to obtain an electrolytic manganese slag sample (E);

[0007] The electrolytic manganese slag sample is calcined to obtain a calcined electrolytic manganese slag sample (xE-i);

[0008] The electrolytic manganese slag sample is added to an acid solution for leaching, and the leaching solution (y%H m E n ) is collected;

[0009] The calcined electrolytic manganese slag sample is immersed in the leaching solution, and then dried to obtain an NH3-SCR catalyst ((y%H m E n ) z-xE j -i).

[0010] In a preferred embodiment of the present invention, the drying temperature is 80° C.-160° C., and the drying time is 8 h-24 h.

[0011] In a preferred embodiment of the present invention, the drying temperature is 80°C, 100°C, 120°C, 140°C or 160°C; and the drying time is 8h, 12h, 16h or 24h.

[0012] In a preferred embodiment of the present invention, the calcination temperature is 400° C.-600° C., and the calcination time is 2 h-6 h.

[0013] In a preferred embodiment of the present invention, the calcination temperature is 400°C, 450°C, 500°C, 550°C or 600°C, and the calcination time is 2h, 3h, 4h, 5h or 6h.

[0014] In a preferred embodiment of the present invention, the acid solution is nitric acid; the mass concentration of the nitric acid is 2.5%-10%; the mass volume ratio of the electrolytic manganese slag original sample to the acid solution is 1g:10-25mL.

[0015] In a preferred embodiment of the present invention, the mass concentration of the nitric acid is 2.5%, 3%, 4%, 5%, 7.5% or 10%.

[0016] In a preferred embodiment of the present invention, the leaching is: first stirring, then standing, the stirring time is 30-90 minutes; the standing time is 2 hours.

[0017] In a preferred embodiment of the present invention, the leaching time is 30 min, 60 min or 90 min.

[0018] In a preferred embodiment of the present invention, the mass volume ratio of the electrolytic manganese slag roasted sample to the leaching solution is 2-8 g:1 mL.

[0019] In a preferred embodiment of the present invention, the immersion time is 12 hours.

[0020] A second aspect of the present invention provides an NH3-SCR catalyst prepared by the above preparation method.

[0021] A third aspect of the present invention provides an application of the above-mentioned NH3-SCR catalyst in catalytic flue gas denitrification; the flue gas contains NH3, NO, N2 and O2.

[0022] The present invention discloses the following technical effects:

[0023] 1. The NH3-SCR catalyst of electrolytic manganese residue activated and self-modified by dilute nitric acid provided by the application has cheap and readily available raw materials, can greatly reduce the production cost, and realizes waste treatment and resource utilization of solid waste.

[0024] 2. In the preparation process of the NH3-SCR catalyst of electrolytic manganese residue activated and self-modified by dilute nitric acid provided by the application, the leaching solution (y% H m E n ) is impregnated on the calcined sample of electrolytic manganese residue (xE-i), so that the content of active elements such as Fe and Mn in the calcined sample of electrolytic manganese residue is increased, thereby improving the denitration performance of the electrolytic manganese residue.

[0025] 3. The NH3-SCR catalyst of electrolytic manganese residue activated and self-modified by dilute nitric acid provided by the application has a simple preparation method, and only needs to impregnate the obtained leaching solution (y% H m E n ) and the calcined sample of electrolytic manganese residue (xE-i) to activate and self-modify the electrolytic manganese residue.

[0026] 4. The NH3-SCR catalyst of electrolytic manganese residue activated and self-modified by dilute nitric acid provided by the application can be used for flue gas denitration under the conditions of a total flow rate of 200 mL / min, a space velocity of 70771 h -1 , a test temperature of 25-450 DEG C, and a simulated tail gas with a component of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2. The denitration efficiency of the catalyst is above 77% in the temperature range of 25-150 DEG C, and the denitration effect is remarkable in the temperature range of 150-450 DEG C, and can reach 100%. BRIEF DESCRIPTION OF DRAWINGS

[0027] In order to more clearly illustrate the technical solutions in the embodiments of the application or the prior art, the drawings needed in the embodiments will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the application, and other drawings can also be obtained by those skilled in the art without creative labor.

[0028] Figure 1 The scanning electron microscope (SEM) of the catalyst sample in Example 1 is shown in the figure;

[0029] Figure 2 The X-ray diffraction (XRD) of the catalyst sample in Example 1 is shown in the figure;

[0030] Figure 3 The scanning electron microscope (SEM) of the catalyst sample in Example 2 is shown in the figure;

[0031] Figure 4 The X-ray diffraction (XRD) of the catalyst sample in Example 2 is shown in the figure;

[0032] Figure 5 Scanning electron microscope (SEM) images of the catalyst samples in Example 3;

[0033] Figure 6 X-ray diffraction (XRD) images of the catalyst samples in Example 3;

[0034] Figure 7 SCR DeNOx efficiency graphs of Example 1 and Examples 4 to 7 under the conditions of Experimental Example 1 and Experimental Examples 4 to 7, respectively;

[0035] Figure 8 N2 selectivity trend graphs of Example 1 and Examples 4 to 7 under the conditions of Experimental Example 1 and Experimental Examples 4 to 7, respectively;

[0036] Figure 9 SCR DeNOx efficiency graphs of Example 2 and Examples 8 to 11 under the conditions of Experimental Example 2 and Experimental Examples 8 to 11, respectively;

[0037] Figure 10 N2 selectivity trend graphs of Example 2 and Examples 8 to 11 under the conditions of Experimental Example 2 and Experimental Examples 8 to 11, respectively;

[0038] Figure 11 SCR DeNOx efficiency graphs of Example 3 and Examples 12 to 16 under the conditions of Experimental Example 3 and Experimental Examples 12 to 16, respectively;

[0039] Figure 12 N2 selectivity trend graphs of Example 3 and Examples 12 to 16 under the conditions of Experimental Example 3 and Experimental Examples 12 to 16, respectively;

[0040] Figure 13 SCR DeNOx efficiency graphs of Example 1, Example 2, Example 3 and Examples 17 to 19 under the conditions of Experimental Example 1, Experimental Example 2, Experimental Example 3 and Experimental Examples 17 to 19, respectively;

[0041] Figure 14 N2 selectivity trend graphs of Example 1, Example 2, Example 3 and Examples 17 to 19 under the conditions of Experimental Example 1, Experimental Example 2, Experimental Example 3 and Experimental Examples 17 to 19, respectively;

[0042] Figure 15 SCR DeNOx efficiency graphs of Example 1, Example 2, Example 3 and Examples 20 to 22 under the conditions of Experimental Example 1, Experimental Example 2, Experimental Example 3 and Experimental Examples 20 to 22, respectively;

[0043] Figure 161, 2, 3 and 20-22 respectively under the conditions of Experimental Example 1, Experimental Example 2, Experimental Example 3 and Experimental Examples 20-22;

[0044] Figure 17 Graph showing the SCR denitration efficiency of the catalysts of Example 3 and Comparative Example 1;

[0045] Figure 18 3 is a graph showing the change trend of N2 selectivity of the catalysts of Example 3 and Comparative Example 1. DETAILED DESCRIPTION

[0046] 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.

[0047] 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.

[0048] 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.

[0049] 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.

[0050] The words “include,” “including,” “have,” “contain,” etc. used in this document are open-ended terms, meaning including but not limited to.

[0051] The manganese slag sources mainly include solid waste in the manganese ore smelting process, mainly from blast furnace manganese iron and silicon manganese alloy production process. The content of manganese is different due to different smelting processes and raw materials, usually between 10% and 30%, and the content of manganese in some high-grade manganese slag can even reach more than 50%. Due to the high manganese grade, it is relatively easy to activate and modify in the reprocessing, and the modified manganese slag has a better application effect. The electrolytic manganese slag is the waste slag produced in the electrolytic manganese production process through manganese carbonate ore, acid leaching, neutralization, filter pressing and other processes, which has low manganese grade and high slag acidity, and is difficult to reuse. Even if the low-grade electrolytic manganese slag is modified and reused, the application effect is often low, and it is difficult to achieve the expected effect. With the increasing stockpiling of electrolytic manganese slag year by year, how to realize the resource treatment of electrolytic manganese slag is a problem to be solved.

[0052] Since the electrolytic manganese slag also contains Fe and Mn elements, if the electrolytic manganese slag is used to make Mn-Fe-based NH3-SCR catalyst, the cost of the denitration catalyst can be reduced, thereby realizing the purpose of waste treatment with waste. Therefore, the NH3-SCR catalyst prepared by activating and self-modifying the electrolytic manganese slag with dilute nitric acid has important application value.

[0053] In the present application, dilute nitric acid is used to leach the electrolytic manganese slag as received, and the leaching solution containing manganese ions and iron ions obtained after solid-liquid separation is then loaded onto the calcined electrolytic manganese slag sample after calcination, and the NH3-SCR catalyst is prepared after drying and sieving. The process of loading the leaching solution containing manganese ions and iron ions obtained by leaching the electrolytic manganese slag as received with dilute nitric acid onto the calcined electrolytic manganese slag sample is a process of modifying the electrolytic manganese slag by utilizing the characteristics of Mn and Fe elements contained in the electrolytic manganese slag, so as to improve the low-temperature catalytic effect while ensuring the high-temperature denitration effect. In the range of 50-150 DEG C, the denitration efficiency is nearly 80%, and in the range of 150-450 DEG C, the denitration efficiency is nearly 100%, and no other external elements are introduced for modification. Secondly, the calcination activation process of the present application is to calcine the electrolytic manganese slag before loading the leaching solution, and the electrolytic manganese slag is not calcined after loading. This is different from the existing technology of leaching modification, drying and then calcination activation.

[0054] The technical solutions described in the present application are conventional solutions in the art, and the reagents or raw materials used are commercially available or publicly disclosed, unless otherwise specified.

[0055] In order to better understand the present application, the following examples are further illustrated, but the content of the present application is not limited to the following examples.

[0056] Example 1

[0057] The electrolytic manganese slag (EMR) after grinding and screening was placed in an oven and dried at 120° C. for 12 h to obtain the electrolytic manganese slag catalyst, named E.

[0058] The catalyst sample E of this embodiment was subjected to SEM, XRD and XRF analysis. Figure 1 As shown in Figure 3, the microstructure of the catalyst is mainly composed of stacked rods and irregular blocks. Figure 2 The XRD results of Sample E show distinct diffraction peaks for CaSO4·2H2O, FeS2, and SiO2, while no distinct diffraction peaks are detected for manganese oxide, possibly existing in an amorphous state. The XRF results in Table 1 show that the original electrolytic manganese slag contains elements such as Fe (52.314%), S (21.461%), Ca (8.163%), Mn (7.308%), and Si (5.799%), with a relatively high Fe content.

[0059] Table 1 Main element composition of electrolytic manganese slag (E) (wt, %)

[0060]

[0061] Example 2

[0062] The E of Example 1 was calcined in a muffle furnace at 500° C. for 4 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 500E-4.

[0063] The catalyst sample 500E-4 of this embodiment was subjected to SEM, XRD and XRF analysis. Figure 3 As shown, Figure 1 The SEM image of catalyst sample E shows that the microstructure of the catalyst after calcination is mainly composed of stacked rods and irregular blocks, but metal oxide lattice stripes appear on the rod-shaped structure, indicating that the metal elements in the sample undergo oxidation reaction after calcination and metal oxides appear. Figure 4 The XRD pattern of the catalyst sample 500E-4 shows obvious CaSO4 and SiO2 diffraction peaks, which are consistent with the Figure 2 Compared to Catalyst Sample E, FeS2 disappears, while Fe2O3 diffraction peaks emerge. No distinct diffraction peaks are detected for manganese oxide, suggesting an amorphous state. The XRF results in Table 2 show that the post-calcination contents of elements such as Fe (56.54%) and Mn (7.54%) in Catalyst Sample 500E-4 increase compared to Catalyst Sample E (Table 1), while the S content (16.304%) decreases.

[0064] Table 2 Main element composition of electrolytic manganese slag calcined sample (500E-4) (wt, %)

[0065]

[0066] Example 3

[0067] Take 20 mL of 5% dilute nitric acid and 1 g of electrolytic manganese residue as original (E) mixed and stirred for 30 min, then stand for 2 h, then solid-liquid separation, get leaching solution (5% H 20 E1), then take 4 ml of leaching solution and 1 g of electrolytic manganese residue calcined sample (500E-4) mixed and impregnated for 12 h, then put into oven and dry at 120℃ for 12 h, get catalyst, named as ((5% H 20 E1)4-500E1-4).

[0068] The catalyst sample ((5% H 20 E1)4-500E1-4) of this example was analyzed by SEM, XRD and XRF. As Figure 5 shown, compared with catalyst sample E( Figure 1 ) and catalyst sample 500E-4( Figure 4 ), the micro-morphology of the catalyst of electrolytic manganese residue self-modified by dilute nitric acid disappeared from rod-like structure to irregular block-like stack. Figure 6 The XRD pattern of the catalyst sample ((5% H 20 E1)4-500E1-4) has obvious CaSO4and SiO2diffraction peaks, and compared with catalyst sample 500E-4( Figure 4 ), the Fe2O3diffraction peak is stronger, and FeMnOOH diffraction peak appears, indicating that after the electrolytic manganese residue is self-modified by dilute nitric acid, the synergistic effect between Fe and Mn is enhanced, and no obvious diffraction peak of manganese oxide is detected, which may be in amorphous state. The XRF results in Table 3 show that the element contents of Fe (57.82%) and Mn (10.31%) in the catalyst sample ((5% H 20 E1)4-500E1-4) are higher than those of catalyst samples E (Table 1) and 500E-4 (Table 2).

[0069] Table 3 Main element composition (wt, %) of electrolytic manganese residue sample self-modified by dilute nitric acid ((5% H 20 E1)4-500E1-4)

[0070]

[0071] Example 4

[0072] E of Example 1 was calcined in a muffle furnace at 400℃ for 4h to obtain electrolytic manganese residue calcined sample catalyst, named as 400E-4.

[0073] Example 5

[0074] E of Example 1 was calcined in a muffle furnace at 450℃ for 4h to obtain electrolytic manganese residue calcined sample catalyst, named as 450E-4.

[0075] Example 6

[0076] The catalyst E prepared in Example 1 was calcined in a muffle furnace at 550° C. for 4 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 550E-4.

[0077] Example 7

[0078] The E of Example 1 was calcined in a muffle furnace at 600° C. for 4 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 600E-4.

[0079] Example 8

[0080] The E of Example 1 was calcined in a muffle furnace at 500° C. for 1 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 500E-1.

[0081] Example 9

[0082] The E of Example 1 was calcined in a muffle furnace at 500° C. for 2 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 500E-2.

[0083] Example 10

[0084] The E of Example 1 was calcined in a muffle furnace at 500° C. for 3 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 500E-3.

[0085] Example 11

[0086] The E of Example 1 was calcined in a muffle furnace at 500° C. for 5 h to obtain an electrolytic manganese slag calcined sample catalyst, which was named 500E-5.

[0087] Example 12

[0088] Take 20mL 2.5% dilute nitric acid and 1g electrolytic manganese slag (E) and mix them for 30min, then let it stand for 2h, and then separate the solid and liquid to obtain the leachate (2.5% H 20 E1), then 4 ml of the leaching solution was mixed with 1 g of electrolytic manganese slag calcined sample (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120 ° C for 12 h to obtain a catalyst named ((2.5% H 20 E1)4-500E1-4).

[0089] Example 13

[0090] Take 20mL 3% dilute nitric acid and 1g electrolytic manganese slag (E) and mix them for 30min, then let them stand for 2h, and then separate the solid and liquid to obtain the leachate (3% H 20E1), then 4 ml of the leaching solution was mixed with 1 g of the roasted sample of electrolytic manganese residue (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120°C for 12 h to obtain a catalyst, which was named ((3% H 20 E1) 4-500E1-4).

[0091] Example 14

[0092] 20 mL of 4% dilute nitric acid was mixed with 1 g of the raw sample of electrolytic manganese residue (E) and stirred for 30 min, then allowed to stand for 2 h, and then solid-liquid separation was performed to obtain a leaching solution (4% H 20 E1), then 4 ml of the leaching solution was mixed with 1 g of the roasted sample of electrolytic manganese residue (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120°C for 12 h to obtain a catalyst, which was named ((4% H 20 E1) 4-500E1-4).

[0093] Example 15

[0094] 20 mL of 7.5% dilute nitric acid was mixed with 1 g of the raw sample of electrolytic manganese residue (E) and stirred for 30 min, then allowed to stand for 2 h, and then solid-liquid separation was performed to obtain a leaching solution (7.5% H 20 E1), then 4 ml of the leaching solution was mixed with 1 g of the roasted sample of electrolytic manganese residue (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120°C for 12 h to obtain a catalyst, which was named ((7.5% H 20 E1) 4-500E1-4).

[0095] Example 16

[0096] 20 mL of 10% dilute nitric acid was mixed with 1 g of the raw sample of electrolytic manganese residue (E) and stirred for 30 min, then allowed to stand for 2 h, and then solid-liquid separation was performed to obtain a leaching solution (10% H 20 E1), then 4 ml of the leaching solution was mixed with 1 g of the roasted sample of electrolytic manganese residue (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120°C for 12 h to obtain a catalyst, which was named ((10% H 20 E1) 4-500E1-4).

[0097] Example 17

[0098] 10 mL of 5% dilute nitric acid was mixed with 1 g of the raw sample of electrolytic manganese residue (E) and stirred for 30 min, then allowed to stand for 2 h, and then solid-liquid separation was performed to obtain a leaching solution (5% H 10 E1), then 4 ml of the leaching solution was mixed with 1 g of the roasted sample of electrolytic manganese residue (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120°C for 12 h to obtain a catalyst, which was named ((5% H 10 E1) 4-500E1-4).

[0099] Example 18

[0100] Take 15 mL of 5% dilute nitric acid and 1 g of electrolytic manganese residue as original (E) mixed and stirred for 30 min, then stand for 2 h, then solid-liquid separation, get leaching solution (5% H 15 E1), then take 4 ml of leaching solution and 1 g of electrolytic manganese residue calcined sample (500E-4) mixed and immersed for 12 h, then put into oven, dry at 120°C for 12 h, get catalyst, named as ((5% H 15 E1)4-500E1-4).

[0101] Example 19

[0102] Take 25 mL of 5% dilute nitric acid and 1 g of electrolytic manganese residue as original (E) mixed and stirred for 30 min, then stand for 2 h, then solid-liquid separation, get leaching solution (5% H 25 E1), then take 4 ml of leaching solution and 1 g of electrolytic manganese residue calcined sample (500E-4) mixed and immersed for 12 h, then put into oven, dry at 120°C for 12 h, get catalyst, named as ((5% H 25 E1)4-500E1-4).

[0103] Example 20

[0104] Take 20 mL of 5% dilute nitric acid and 1 g of electrolytic manganese residue as original (E) mixed and stirred for 30 min, then stand for 2 h, then solid-liquid separation, get leaching solution (5% H 20 E1), then take 2 ml of leaching solution and 1 g of electrolytic manganese residue calcined sample (500E-4) mixed and immersed for 12 h, then put into oven, dry at 120°C for 12 h, get catalyst, named as ((5% H 20 E1)2-500E1-4).

[0105] Example 21

[0106] Take 20 mL of 5% dilute nitric acid and 1 g of electrolytic manganese residue as original (E) mixed and stirred for 30 min, then stand for 2 h, then solid-liquid separation, get leaching solution (5% H 20 E1), then take 6 ml of leaching solution and 1 g of electrolytic manganese residue calcined sample (500E-4) mixed and immersed for 12 h, then put into oven, dry at 120°C for 12 h, get catalyst, named as ((5% H 20 E1)6-500E1-4).

[0107] Example 22

[0108] Take 20mL of 5% dilute nitric acid and 1g of electrolytic manganese slag (E) and mix them for 30min, then let them stand for 2h, and then separate the solid and liquid to obtain the leachate (5% H 20 E1), then 8 ml of the leaching solution was mixed with 1 g of electrolytic manganese slag roasted sample (500E-4) and impregnated for 12 h, and then placed in an oven and dried at 120 ° C for 12 h to obtain a catalyst named ((5% H 20 E1)8-500E1-4).

[0109] In the above, Example 1 is the preparation of electrolytic manganese slag as is (E); Example 2 and Examples 4 to 11 are the preparation of electrolytic manganese slag roasted samples (xE-i); Example 3 and Examples 12 to 22 are the preparation of electrolytic manganese slag activated and self-modified by dilute nitric acid (y% H m E n ) z -xE j -i) Preparation.

[0110] Experimental Example 1

[0111] The catalyst E of Example 1 was fixed in a tube furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature is 25-450°C. Catalyst E achieves a denitration efficiency of 61% in the 25-150°C temperature range, with N2 selectivity above 100%. In the 150-450°C temperature range, the denitration efficiency peaks at 97%, with N2 selectivity above 85%.

[0112] Experimental Example 2

[0113] The 500E-4 catalyst of Example 2 was fixed in a tubular furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature is 25-450°C. The 500E-4 catalyst has a denitration efficiency of approximately 80% in the 25-150°C temperature range, with N2 selectivity remaining above 100%. In the 150-450°C temperature range, the denitration efficiency is around 96%, with N2 selectivity remaining above 94%.

[0114] Experimental Example 3

[0115] Example 3 (5% H 20 E1) 4-500E1-4) The catalyst was fixed in a tube furnace and introduced with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h-1 , the test temperature is 25~450℃. ((5%H 20 The denitrification efficiency of E1)4-500E1-4) catalyst is about 80% in the temperature range of 25-150℃, and the N2 selectivity remains above 100%. In the temperature range of 150-450℃, the denitrification efficiency can reach 100%, and the N2 selectivity remains above 96%.

[0116] Experimental Example 4

[0117] The 400E-4 catalyst of Example 4 was fixed in a tubular furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature was 25-450°C. The 400E-4 catalyst achieved a maximum denitration efficiency of 69% in the 25-150°C temperature range, with N2 selectivity remaining above 100%. In the 150-450°C temperature range, the denitration efficiency reached a maximum of 94%, with N2 selectivity remaining above 94%.

[0118] Experimental Example 5

[0119] The 450E-4 catalyst of Example 5 was fixed in a tubular furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature is 25-450°C. The 450E-4 catalyst achieves a maximum denitration efficiency of 74% in the 25-150°C temperature range, with N2 selectivity remaining above 100%. In the 150-450°C temperature range, the denitration efficiency reaches a maximum of 96%, with N2 selectivity remaining above 95%.

[0120] Experimental Example 6

[0121] The 550E-4 catalyst of Example 6 was fixed in a tubular furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature is 25-450°C. The 550E-4 catalyst achieves a maximum denitration efficiency of 78% in the 25-150°C temperature range, with N2 selectivity remaining above 100%. In the 150-450°C temperature range, the denitration efficiency reaches a maximum of 95%, with N2 selectivity remaining above 85%.

[0122] Experimental Example 7

[0123] The 600E-4 catalyst of Example 7 was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 The test temperature was 25-450°C. The 600E-4 catalyst had a denitration efficiency of 59% at a temperature of 25-150°C, and the N2 selectivity was maintained at 100% or more. The denitration efficiency was 90% at a temperature of 150-450°C, and the N2 selectivity was maintained at 95% or more.

[0124] Experimental Example 8

[0125] The 500E-1 catalyst of Example 8 was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 The test temperature was 25-450°C. The 500E-1 catalyst had a denitration efficiency of 90% at a temperature of 350°C, and the N2 selectivity was maintained at 91% or more.

[0126] Experimental Example 9

[0127] The 500E-2 catalyst of Example 9 was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 The test temperature was 25-450°C. The 500E-2 catalyst had a denitration efficiency of 90% at a temperature of 350°C, and the N2 selectivity was maintained at 92% or more.

[0128] Experimental Example 10

[0129] The 500E-3 catalyst of Example 10 was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 The test temperature was 25-450°C. The 500E-3 catalyst had a denitration efficiency of 90% at a temperature of 350°C, and the N2 selectivity was maintained at 91% or more.

[0130] Experimental Example 11

[0131] The 500E-5 catalyst of Example 11 was fixed in a tubular furnace and fed with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 The test temperature is 25-450°C. The 500E-5 catalyst has the highest denitrification efficiency at 350°C, reaching 90%, and the N2 selectivity remains above 92%.

[0132] Experimental Example 12

[0133] Example 12 (2.5% H 20 E1)4-500E1-4) catalyst was fixed in a tube furnace and introduced with simulated tail gas (composition: 500ppm NO, 500ppm NH3, 5vol.% O2 and N2) at a total flow rate of 200mL / min and a space velocity of 70771h -1 , the test temperature is 25~450℃. ((2.5%H 20 The denitrification efficiency of E1)4-500E1-4) catalyst is as high as 61% in the temperature range of 25-150℃, and the N2 selectivity remains above 100%. The denitrification efficiency is as high as 95% in the temperature range of 150-450℃, and the N2 selectivity remains above 87%.

[0134] Experimental Example 13

[0135] Example 13 ((3% H 20 E1) 4-500E1-4) The catalyst was fixed in a tube furnace and introduced with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 , the test temperature is 25~450℃. ((3%H 20 The denitrification efficiency of E1)4-500E1-4) catalyst is as high as 62% in the temperature range of 25-150°C, and the N2 selectivity remains above 100%. The denitrification efficiency is as high as 90% in the temperature range of 150-450°C, and the N2 selectivity remains above 93%.

[0136] Experimental Example 14

[0137] Example 14 ((4% H 20 E1) 4-500E1-4) The catalyst was fixed in a tube furnace and introduced with simulated tail gas (composition: 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) at a total flow rate of 200 mL / min and a space velocity of 70771 h -1 , the test temperature is 25~450℃. ((4%H 20E1)4-500E1-4) catalyst has the highest denitration efficiency of 72% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 95% in the temperature range of 150-450°C, and the N2 selectivity is kept above 94%.

[0138] Experimental Example 15

[0139] ((7.5% H 20 E1)4-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h -1 ((7.5% H 20 E1)4-500E1-4) catalyst has the highest denitration efficiency of 44% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 94% in the temperature range of 150-450°C, and the N2 selectivity is kept above 93%.

[0140] Experimental Example 16

[0141] ((10% H 20 E1)4-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h -1 ((10% H 20 E1)4-500E1-4) catalyst has the highest denitration efficiency of 55% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 85% in the temperature range of 150-450°C, and the N2 selectivity is kept above 89%.

[0142] Experimental Example 17

[0143] ((5% H 10 E1)4-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through the catalyst at a total flow rate of 200 mL / min and a space velocity of 70 771 h -1 ((5% H 10E1)4-500E1-4) catalyst has the highest denitration efficiency of 49% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 99% in the temperature range of 150-450°C, and the N2 selectivity is kept above 91%.

[0144] Experimental Example 18

[0145] ((5% H 15 E1)4-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through, with a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 ((5% H 15 E1)4-500E1-4) catalyst has the highest denitration efficiency of 52% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 93% in the temperature range of 150-450°C, and the N2 selectivity is kept above 92%.

[0146] Experimental Example 19

[0147] ((5% H 25 E1)4-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through, with a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 ((5% H 25 E1)4-500E1-4) catalyst has the highest denitration efficiency of 60% in the temperature range of 25-150°C, and the N2 selectivity is kept above 100%; and the highest denitration efficiency of 93% in the temperature range of 150-450°C, and the N2 selectivity is kept above 94%.

[0148] Experimental Example 20

[0149] ((5% H 20 E1)2-500E1-4) catalyst was fixed in a tube furnace, and simulated tail gas (compositions of 500 ppm NO, 500 ppm NH3, 5 vol.% O2 and N2) was passed through, with a total flow rate of 200 mL / min and a space velocity of 70 771 h-1. -1 ((5% H 20The denitration efficiency of the E1)2-500E1-4) catalyst was highest at 59% in the temperature range of 25-150°C, and the N2 selectivity was maintained at 100% or more. The denitration efficiency was highest at 92% in the temperature range of 150-450°C, and the N2 selectivity was maintained at 89% or more.

[0150] Experimental Example 21

[0151] ((5% H 20 The E1)2-500E1-4) catalyst was fixed in a tube furnace, and a simulated tail gas (comprising 500 ppm NO, 500 ppm NH3, 5 vol.% O2, and N2) was introduced at a total flow rate of 200 mL / min and a space velocity of 70,771 h"1. The test temperature was 25-450°C. The denitration efficiency of the ((5% H -1 ((5% H 20 The denitration efficiency of the E1)2-500E1-4) catalyst was highest at 59% in the temperature range of 25-150°C, and the N2 selectivity was maintained at 100% or more. The denitration efficiency was highest at 92% in the temperature range of 150-450°C, and the N2 selectivity was maintained at 89% or more.

[0152] Experimental Example 22

[0153] ((5% H 20 The E1)2-500E1-4) catalyst was fixed in a tube furnace, and a simulated tail gas (comprising 500 ppm NO, 500 ppm NH3, 5 vol.% O2, and N2) was introduced at a total flow rate of 200 mL / min and a space velocity of 70,771 h"1. The test temperature was 25-450°C. The denitration efficiency of the ((5% H -1 ((5% H 20 The denitration efficiency of the E1)2-500E1-4) catalyst was highest at 59% in the temperature range of 25-150°C, and the N2 selectivity was maintained at 100% or more. The denitration efficiency was highest at 92% in the temperature range of 150-450°C, and the N2 selectivity was maintained at 89% or more.

[0154] The results of Experimental Example 1 and Experimental Examples 4-7 are shown in Figure 7 and Figure 8Catalyst E was calcined at 400°C, 450°C, 500°C, 550°C, and 600°C for 4 hours to obtain catalysts 400E-4, 450E-4, 500E-4, 550E-4, and 600E-4. The calcined catalysts xE-i all exhibited N2 selectivities exceeding 90% within the temperature range of 25–450°C. Compared to catalyst E, catalyst 500E-4 achieved a denitration efficiency exceeding 81% within the temperature range of 25–150°C. While slightly lower than catalyst E within the temperature range of 150–450°C, the denitration efficiency of catalyst 500E-4 remained above 90%, exceeding that of the other calcined catalysts. In contrast, catalysts E, 400E-4, 450E-4, 550E-4, and 600E-4 achieved a maximum denitration efficiency of only 78% within the temperature range of 25–150°C, and their denitration efficiency within the temperature range of 150–450°C was lower than that of catalyst 500E-4. The reason may be that calcination can make the metal generate metal oxides that are beneficial to the NH3-SCR reaction and improve the synergistic effect between metals. Figure 2 Catalyst samples E and Figure 5 The XRD pattern of catalyst sample 500E-4 shows the appearance of an Fe2O3 diffraction peak after calcination, likely due to enhanced Fe-Mn synergy. Mn, a key element in low-temperature NH3-SCR catalysts, improves the low-temperature denitration efficiency of 500E-4. Therefore, calcination not only improves the low-temperature denitration efficiency of the E catalyst but also increases its N2 selectivity. However, maintaining the high-temperature denitration efficiency of the E catalyst is difficult. Therefore, it is necessary to simultaneously improve the low-temperature denitration efficiency of the E catalyst and maintain its high-temperature denitration efficiency.

[0155] The results of Experiment 2, 8 to 11 are as follows Figure 9 and Figure 10 Different calcination times have a great influence on the denitrification efficiency of the calcined 500E-i catalyst. The E catalyst was calcined at 500℃ for 1, 2, 3, 4 and 5h to prepare 500E-1, 500E-2, 500E-3, 500-4 and 500E-5 catalysts. The denitrification efficiency of the 500E-4 catalyst was higher than that of the E, 500E-1, 500E-2, 500E-3 and 500E-5 catalysts in the entire temperature range, and the N2 selectivity was also higher than that of the 500E-1, 500E-2, 500E-3 and 500E-5 catalysts, all above 90%.

[0156] The results of Experimental Example 3 and Experimental Examples 12 to 16 are as follows Figure 11 and Figure 12 , leachates with different nitric acid concentrations ((y% H m E n ) z -xE j-i) The N2 selectivity of the catalyst was above 85%. The nitric acid concentrations were 2.5%, 3%, 4%, 7.5%, and 10% respectively ((2.5% H 20 E1)4-500E1), ((3% H 20 E1)4-500E1-4), ((4% H 20 E1)4-500E1-4), ((7.5% H 20 E1)4-500E1-4), ((10% H 20 Compared with E catalyst and 500E-4 catalyst, E1-4-500E1-4) catalyst has only ((4%H 20 The denitration efficiency of E1)4-500E1-4) catalyst is higher than that of E catalyst, but the denitration efficiency is difficult to maintain in the temperature range of 150-450℃, and the denitration efficiency is higher than that of 500E-4 catalyst only in the temperature range of 200-300℃. 20 The E1)4-500E1-4) catalyst has a higher denitration efficiency than the E catalyst in the entire temperature range of 25-450°C. Not only does the denitration efficiency increase from 62% to 77% in the temperature range of 25-150°C, but while maintaining the denitration efficiency of the E catalyst in the temperature range of 150-450°C at more than 97%, the denitration efficiency is increased by 2-5%, reaching 100% denitration efficiency, and the N2 selectivity is maintained at more than 97% in the entire test range. ((5%H 20 Compared with the 500E-4 catalyst, the denitrification efficiency of the E1)4-500E1-4) catalyst is slightly lower than that of the 500E-4 catalyst in the temperature range of 25-150°C, but the denitrification efficiency in the temperature range of 150-450°C is significantly better than that of the 500E-4 catalyst, and the N2 selectivity is better than that of the 500E-4 catalyst.

[0157] The results of Experimental Examples 1, 2, 3 and 17 to 19 are as follows Figure 13 and Figure 14 , ((y% H m E n ) z -xE j -i) The N2 selectivity of the catalyst is above 85% in the temperature range of 25-450℃. The ratio of nitric acid dosage to E is 10ml / g, 15ml / g, 25ml / g respectively. 10 E1)4-500E1), ((5% H 15 E1)4-500E1), ((5% H 25E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 10 E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 15 E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 20 E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 20 E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range.

[0158] The results of experimental example 1, experimental example 2, experimental example 3 and experimental example 20-22 are shown in the following table. Figure 15 and Figure 16 ((y%H m E n ) z -xE j i) The N2 selectivity of the catalysts is all above 85%. The ((5%H 20 E1)2-500E1-4), ((5%H 20 E1)6-500E1-4), ((5%H 20 E1)4-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 20 E1)2-500E1-4), ((5%H 20 E1)8-500E1-4) catalyst, the denitration efficiency at the temperature range of 25-450°C is higher than that of E catalyst, not only the denitration efficiency at the temperature range of 25-150°C is increased from 62% to 77%, but also the denitration efficiency at the temperature range of 150-450°C is increased by 2-5% while keeping the denitration efficiency of E catalyst at the temperature range of 150-450°C higher than 97%, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range.20 E1)4-500E1-4) catalyst, the denitration efficiency is higher than that of the E catalyst in the whole temperature range of 25-450°C, not only is the denitration efficiency increased from 62% to 77% in the temperature range of 25-150°C, but also is the denitration efficiency increased by 2-5% in the temperature range of 150-450°C while keeping the denitration efficiency of the E catalyst higher than 97% in the temperature range of 150-450°C, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range. 20 E1)4-500E1-4) catalyst, the denitration efficiency is higher than that of the E catalyst in the whole temperature range of 25-450°C, not only is the denitration efficiency increased from 62% to 77% in the temperature range of 25-150°C, but also is the denitration efficiency increased by 2-5% in the temperature range of 150-450°C while keeping the denitration efficiency of the E catalyst higher than 97% in the temperature range of 150-450°C, reaching 100% denitration efficiency, and the N2 selectivity is kept above 97% in the whole test range.

[0159] Comparative Example 1

[0160] 1) The electrolytic manganese residue was ground, sieved, dried, and electrolytic manganese residue as received (E) was obtained;

[0161] 2) 1 g of electrolytic manganese residue as received was added to 20 ml of dilute nitric acid with a mass concentration of 5% and leached, and the leaching solution (5% H 20 E1) was collected.

[0162] 3) 1 g of electrolytic manganese residue as received (E) was impregnated in 4 ml of the leaching solution (5% H 20 E1), and after standing, dried and calcined (500°C, 4 h) to obtain a catalyst ((5% H 20 E1)4-E1-500℃-4).

[0163] Comparative Example 1 is a scheme of calcining after loading the leaching solution on the electrolytic manganese residue as received (E), compared with the scheme of calcining first and then loading of the present application (Example 3), the denitration performance is as shown in Table 1 (the test process refers to Test Example 3), the catalyst ((5% H Figure 17 , 18 E1)4-E1-500℃-4) calcined after loading, the denitration efficiency in the range of 50-450°C is lower than that of the catalyst (5% H 20 E1)4-500E1-4) calcined first and then loaded, and the N2 selectivity in the range of 50-450°C is also lower than that of the catalyst ((5% H 20 E1)4-500E1-4). 20 E1)4-500E1-4).

[0164] The above only describes the preferred embodiments of the present application, and it should be noted that for ordinary skilled persons in the art, several improvements and refinements can be made without departing from the principles of the present application, and these improvements and refinements should also be considered as the protection scope of the present application.

Claims

1. A NH 3- The preparation method of the SCR catalyst is characterized in that: The following steps are involved: Grinding and sieving the electrolytic manganese slag, and then drying the electrolytic manganese slag to obtain the original electrolytic manganese slag; calcining the electrolytic manganese slag original sample to obtain an electrolytic manganese slag calcined sample; adding the electrolytic manganese slag as is into an acid solution for leaching, and collecting the leachate; The electrolytic manganese slag roasted sample was immersed in the leachate and then dried to obtain NH 3- SCR catalyst; The calcination temperature is 400-600°C and the calcination time is 2h-6h; The acid solution is nitric acid; the mass concentration of the nitric acid is 2.5%-10%; the mass volume ratio of the electrolytic manganese slag sample to the acid solution is 1g:10-25mL; The mass volume ratio of the electrolytic manganese slag roasted sample to the leaching solution is 1g:2mL, 1g:4mL, 1g:6mL or 1g:8mL.

2. NH according to claim 1 3- The preparation method of the SCR catalyst is characterized in that: The drying temperature is 80° C.-160° C., and the drying time is 8 hours-24 hours.

3. NH according to claim 1 3- The preparation method of the SCR catalyst is characterized in that: The leaching process is as follows: stirring first and then standing still; the stirring time is 30-90 minutes; and the standing time is 2 hours.

4. NH according to claim 1 3- The preparation method of the SCR catalyst is characterized in that: The immersion time is 12 hours.

5. NH prepared by the preparation method according to any one of claims 1 to 4 3- SCR catalyst.

6. NH according to claim 5 3- Application of SCR catalyst in catalytic denitrification of flue gas; the flue gas contains NH3, NO, N2 and O2.

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