Manganese-based multi-element ultralow-temperature denitration catalyst as well as preparation method and application thereof

Abstract

The invention provides a manganese-based multi-element ultralow-temperature denitration catalyst as well as a preparation method and application thereof, and relates to the technical field of catalysts and environmental protection. The preparation method comprises the following steps: 1) adding an organic solvent and a dispersing agent into an auxiliary precursor solution containing a strontium source, a zirconium source and a lanthanum source, uniformly mixing, adding a precipitator for precipitation reaction, and performing primary ultrasonic treatment on the reacted material to obtain an auxiliary precursor; 2) calcining the auxiliary agent precursor to obtain an oxide corresponding to the catalyst auxiliary agent; 3) dispersing a manganese source, an iron source and the corresponding oxide of the catalyst auxiliary agent in pure water or deionized water, and performing intermittent ultrasonic treatment and aging treatment to obtain a catalyst precursor; and 4) calcining the catalyst precursor at low temperature to obtain the manganese-based multi-element ultralow-temperature denitration catalyst. The prepared manganese-based multi-element ultralow-temperature denitration catalyst is rich in pore channels and relatively large in specific surface area, active substances and auxiliary elements are uniformly dispersed, and the catalyst has excellent ultralow-temperature catalytic activity.

Description

Technical Field

[0001] The present invention relates to the technical field of catalysts and environmental protection, and in particular to a manganese-based multi-element ultra-low temperature denitration catalyst and a preparation method and application thereof. Background Art

[0002] Excessive emission of NO X (Nitrogen oxides) can cause many harms to the human body and the natural environment. X Can cause many diseases such as bronchitis, pulmonary edema, etc.; NO X A series of reactions will occur with hydrocarbons under sunlight, producing secondary pollutants such as ozone; nitrogen oxides promote the formation of acid rain, thereby damaging vegetation, soil, and lakes; in addition, nitrogen oxides will also cause damage to the ozone layer and cause the greenhouse effect. Therefore, controlling the emission of NO into the atmosphere is necessary. X , which has far-reaching impact.

[0003] Nowadays, most of the NO X The production of NO is related to human industrial production and the combustion of fossil fuels required for automobile power. The flue gas produced by industrial processes, especially the combustion of fuel in power plants, is considered to be NO X The main source of NO X A common method of emission reduction is to use selective catalytic reduction (SCR), that is, using a reducing agent such as NH3 to reduce NO X Selectively reduce to non-polluting N2. This method is relatively mature, and V2O5-based catalysts have been used in industrial applications to catalyze NO at 300-400℃. X Reduction can achieve high conversion rates; however, V2O5 catalysts are prone to volatility and loss, which leads to reduced catalytic efficiency and environmental pollution. The higher operating temperature also increases the operating cost of the overall process.

[0004] In recent years, low-temperature denitrification catalysts have become a hot topic in research. However, the operating temperature window of the developed low-temperature denitrification catalysts is mostly above 180°C, and the temperature of the exhaust gas containing nitrogen oxides drops significantly after dust removal and desulfurization, mostly around 150°C or even lower. In order to match the working temperature of the catalyst, it is often necessary to install additional exhaust gas preheating / heat exchange devices, which invisibly increases the operating cost of denitrification. The ultra-low temperature denitrification catalyst (operating temperature ≤ 150°C) can not only reduce energy consumption and save costs, but also has environmental applicability, so it has become the focus of research and development.

[0005] The commonly used ultra-low temperature denitrification catalyst is a manganese-based multi-metal composite catalyst. The structural properties, redox ability, catalytic reaction mechanism, etc. of the multi-metal composite SCR catalyst are affected by the preparation method, which further affects the SCR activity of the catalyst. The preparation methods of manganese-based denitration catalysts include precipitation method, impregnation method, sol-gel method, etc. For example, patent CN108993528A uses impregnation method to prepare iron-modified MnCoCeFe ultra-low temperature denitration catalyst, which uses titanium dioxide and porous silica gel balls as composite carriers, and its catalytic denitration activity is 90% at 146°C; patent CN102019187A uses cordierite honeycomb ceramics loaded with TiO2-SiO2 coating as carriers, and Mn, Fe, Ce, Zr, W and other elements as active substances. The catalyst is prepared by precipitation method, but the ultra-low temperature activity is poor, and the NO conversion rate is only about 54.4% at 120°C; the optimal denitration temperature of existing ultra-low temperature SCR catalysts is mostly around 100-150°C, and further reducing the temperature will significantly affect the catalyst performance. Therefore, modification is still needed to improve the denitration performance of the catalyst in a lower temperature environment.

[0006] Adding a single carrier or a composite carrier is a common method to increase the specific surface area of ​​the catalyst and thus improve the catalytic activity. For example, patent CN105289644A invented a flat-plate sulfur-resistant low-temperature SCR denitrification catalyst, which uses a Ce-ZrO2 composite oxide with a weight percentage of 65-80% as a carrier and can be used for ultra-low temperature denitrification at 80-150°C; patent CN109876856A invented a low-temperature flue gas denitrification catalyst with a TiO2-molecular sieve composite as a carrier; patent CN103638942A invented a catalyst carrier mainly prepared from powders of one or more combinations of titanium dioxide (TiO2), aluminum oxide (Al2O3) and zirconium dioxide (ZrO2).

[0007] In addition, multi-metal doping is also a common means to improve the ultra-low temperature activity of catalysts. However, the dispersibility of each component in the multi-metal doped catalyst will affect the denitration performance of the multi-component composite catalyst. In order to improve the dispersibility, some studies have modified the catalyst by ultrasound, such as the study by Yong Xiaolong et al., the effect of ultrasound on the performance of MnOx / TiO2 low-temperature SCR denitration catalyst (Anhui Chemical Industry Vol. 46, No. 5, 2020), and the study by Deng Hong et al.: Preparation of morpholine catalyst by ultrasonic impregnation and its catalytic performance (Chemical Progress Vol. 34, No. 2, 2015), etc., all of which are to improve the loading and dispersibility in the impregnation method. It is worth noting that during the roasting process of the traditional impregnation method, low-valent manganese salts are easily decomposed directly on the surface of the carrier and agglomerated to form larger particles.

[0008] In view of this, there is an urgent need to develop a catalyst preparation method and a catalyst for improving the ultra-low temperature denitration activity of a denitration catalyst to meet the needs of the market and industrialization. Summary of the invention

[0009] In view of the deficiencies in the prior art, the present invention discloses a manganese-based multi-element ultra-low temperature denitration catalyst and a preparation method and application thereof. The manganese-based multi-element ultra-low temperature denitration catalyst degrades NO at 50°C. X The removal rate of NO can reach 86% at 75℃. X The removal rate reaches 98%, with excellent ultra-low temperature activity.

[0010] In order to achieve the above technical objectives, on the one hand, the present invention provides a method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the preparation method comprising the following steps:

[0011] (1) adding an organic solvent and a dispersant to an additive precursor solution containing a strontium source, a zirconium source, and a lanthanum source, mixing them evenly, and then adding a precipitant to perform a precipitation reaction. After the reaction is completed, the material is subjected to a first ultrasonic treatment to obtain an additive precursor;

[0012] (2) the promoter precursor is calcined to obtain the catalyst promoter corresponding oxide;

[0013] (3) dispersing a manganese source, an iron source and the corresponding oxide of the catalyst promoter in pure water or deionized water, and subjecting the mixture to intermittent ultrasonic treatment and aging treatment to obtain a catalyst precursor;

[0014] (4) The catalyst precursor is calcined at low temperature to obtain the manganese-based multi-element ultra-low temperature denitrification catalyst.

[0015] The above technical solution promotes the improvement of the catalytic performance of the catalyst under ultra-low temperature conditions through the coordinated cooperation of multiple technical features:

[0016] First, based on a large amount of experimental data, the present invention selects transition metal manganese and iron as active components, and co-dopes them with strontium, zirconium and lanthanum as additives. The synergistic effect of manganese and iron elements and the interaction between the active components and the additives are used to achieve a good dispersion effect, thereby improving the NOx removal rate of the catalytic reaction.

[0017] Furthermore, the research and development team of the present invention has found that increasing the high-valent state content of active components manganese and iron in the denitration catalyst is beneficial to promoting the catalytic activity of the denitration catalyst. Compared with the traditional catalyst preparation method of co-precipitation of auxiliary elements and active components, the present invention adopts a preparation process combining "precipitation-impregnation" and sets up an operation mode of step-by-step calcination of auxiliary agents and active metals, so that in the actual process, different temperatures can be used in step (2) and step (4) to calcine the auxiliary agent precursor and the catalyst precursor, respectively. This can avoid the coking condition caused by high-temperature calcination of active components with auxiliary elements in the traditional co-precipitation method, and it is also convenient to select a suitable calcination temperature at different stages, especially when calcining the catalyst precursor, so as to increase the relative content of high-valent manganese and iron in the main active elements and further form an amorphous state of manganese oxide, thereby improving the denitration activity of the catalyst.

[0018] In addition, the research and development team of the present invention discovered through exploratory experiments that the calcination temperatures of manganese and iron are similar. Therefore, the present invention uses manganese and iron as active components of the catalyst to improve the operability of the preparation process and is also conducive to obtaining a catalyst with better catalytic performance.

[0019] The above technical solution improves the physical structure characteristics of the prepared catalyst and further enhances the low-temperature catalytic performance of the catalyst through multiple synergistic technical features:

[0020] In the precipitation process, adding an organic solvent to the additive precursor solution can provide a suitable viscosity for the precipitation reaction system. Since the viscosity of the mixed solution will affect the diffusion rate of ions in the system and the precipitation reaction, the ion diffusion rate and the precipitation rate are regulated. The addition of the dispersant can promote the full dispersion of the additive elements, which is conducive to obtaining a catalyst additive with sufficient reaction and more uniform element distribution. In addition, the precipitation process also performs the first ultrasonic operation on the material after the precipitation reaction. With the help of the transient cavitation effect generated by the ultrasonic wave, the aggregation of crystal nuclei is effectively suppressed, and the violent impact and physical stirring effect will significantly improve the dispersibility of each element in the precipitation of the additive, and can provide a better dispersion effect in combination with the dispersant.

[0021] In the impregnation process, the present invention is assisted by intermittent ultrasonic treatment, which can not only allow the main active component to fully penetrate into the inside and outside of the auxiliary agent through sufficient ultrasonic time to achieve better dispersion effect of the active component and auxiliary agent elements, but also avoid the collapse of the auxiliary agent pores and damage to the structure due to continuous long-term ultrasound.

[0022] In combination with the above technical features, the preparation method of the manganese-based multi-component ultra-low temperature denitrification catalyst of the present invention can improve the crystal growth process and structure of the additive and the dispersibility between the elements. The prepared catalyst has the characteristics of regular particle morphology, uniform particle size, uniform dispersion of the catalyst components, rich and regular pore structure, etc. The embodiments and comparative examples verify that the manganese-based multi-component ultra-low temperature denitrification catalyst of the present invention exhibits better catalytic activity in the denitrification reaction process.

[0023] In a further example of the present invention, the molar ratio of the manganese source, iron source, strontium source, zirconium source and lanthanum source is 60: (10-40): (2-20): (3-14): (1-10) in terms of metal elements. The exploration and optimization of the ratio of active components to auxiliary elements is conducive to the synergistic catalytic effect of active components and auxiliary elements, and to increase the proportion of high-valent states of active components manganese and iron. In an optional example of the present invention, the molar ratio of the manganese source, iron source, strontium source, zirconium source and lanthanum source in terms of metal elements is 60: (20-30): (3-17): (5-10): (1-8) in terms of catalyst; in a preferred example of the present invention, the molar ratio of the manganese source, iron source, strontium source, zirconium source and lanthanum source is preferably 60: 25: 12: 7: 3.

[0024] In a further example of the present invention, the organic solvent includes at least one of n-butanol, n-propanol, and glycerol. The embodiment of the present invention shows an example of preparing a manganese-based multi-element ultra-low temperature denitration catalyst using different organic solvents. Furthermore, the amount of the organic solvent added is 20%-50% of the volume of the additive precursor solution. By adding an appropriate amount of organic solvent to the additive precursor solution, the preparation system can present a state with a certain viscosity, which is beneficial to the regulation of the rate of the subsequent precipitation reaction. In an optional example of the present invention, the amount of the organic solvent added is preferably 30%-50% of the volume of the additive precursor solution.

[0025] In a further example of the present invention, the dispersant includes at least one of sulfonated polystyrene, sodium polyacrylate, and polyacrylamide. The embodiment of the present invention shows an example of using different dispersants to make a manganese-based multi-element ultra-low temperature denitrification catalyst. Furthermore, the amount of the dispersant added is 0.3%-2.0% of the mass of the oxide corresponding to the catalyst aid. By exploring the amount of dispersant, it is convenient to combine the addition of organic solvents to comprehensively control the rate of the precipitation reaction; it should be noted that in the actual process, the amount of the catalyst aid obtained by theoretical calculation can be used to determine the amount of dispersant to be added. In an optional example of the present invention, the amount of the dispersant added is preferably 0.5%-1.5% of the mass of the oxide corresponding to the catalyst aid.

[0026] In a further example of the present invention, the precipitant includes an aqueous solution of an alkaline carbonate; further, the alkaline carbonate includes at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate and ammonium bicarbonate, and sodium carbonate is further preferred.

[0027] It should be noted that the present invention does not limit the method of adding the precipitant, and dropwise addition can be selected to improve the operability of the precipitation reaction. Those skilled in the art can select a suitable method of adding the precipitant according to their needs.

[0028] In a further example of the present invention, the pH value of the material after the precipitation reaction in step (1) is 9-11. It should be noted that the present invention does not limit the amount of the precipitant, and in order to promote the sufficient precipitation of the auxiliary element, an excess of precipitant can be optionally added; in actual operation, the appropriate end point of the reaction can be determined according to the pH value of the material after the precipitation reaction is completed, or the addition of a precipitant of about 1.5-2 times the amount of precipitant required for the auxiliary element can be considered to promote the complete reaction.

[0029] In a further example of the present invention, the temperature of the first ultrasonic treatment in step (1) is 60-80°C, the ultrasonic power is 40w-240w, and the duration is 2-5h. By performing continuous ultrasonic operation at appropriate temperature conditions with appropriate power and duration, it is beneficial to regulate the crystallization rate of the additive and ultimately optimize the catalytic performance of the prepared catalyst. The embodiments of the present invention and the comparative examples show the catalytic effects of the catalysts prepared under different ultrasonic conditions. Optionally, the first ultrasonic operation is performed at 70°C.

[0030] In a further example of the present invention, the temperature of calcining the auxiliary agent precursor in step (2) is 600-1200°C, and the calcination time is 3-8h. Compared with the calcination temperature of the active component, the calcination temperature of the auxiliary agent precursor is higher. Further optionally, the temperature of calcining the auxiliary agent precursor in step (2) is 900-1100°C. The examples and comparative examples explore the catalytic performance of the catalysts obtained at different auxiliary agent calcination temperatures. Optionally, the calcination operation is carried out under an air atmosphere.

[0031] It is worth noting that after the first ultrasonic treatment in step (1), the obtained auxiliary agent precursor reaction system is in a suspension state. Optionally, the step (1) also includes solid-liquid separation of the material after the first ultrasonic treatment, and solid-liquid separation can be performed by centrifugation, filtration, suction filtration and other operations, and suction filtration can be further selected. Further optionally, the step (1) also includes drying the solid phase after solid-liquid separation, and the temperature of the drying operation can be selected from 100-120°C, and the drying time can be selected from 8-24h. Further optionally, the step (1) also includes grinding the catalyst auxiliary agent, and obtaining a catalyst auxiliary agent powder with a particle size of 30-300 mesh by grinding, which is convenient for subsequent dispersion, impregnation and adsorption.

[0032] In a further example of the present invention, the power of the intermittent ultrasound in step (3) is 50-100w, each ultrasound is 30-90min, and then stopped for 15-25min, and the intermittent treatment cycle is 3-5 times. Intermittent ultrasound is beneficial for the active components to be fully dispersed and impregnated into the catalyst additive, and at the same time, it is beneficial to improve the pore structure of the catalyst.

[0033] In a further example of the present invention, the temperature of the aging treatment is 15-30° C., and the treatment time is 5-10 h.

[0034] Optionally, the step (3) further comprises solid-liquid separation of the aged material, and solid-liquid separation can be performed by centrifugation, filtration, etc., and filtration can be further performed. Further, the step (3) further comprises drying the solid phase obtained after separation, and the drying temperature can be 100-120°C, and the drying time can be 5-20h.

[0035] In a further example of the present invention, the calcination temperature of the catalyst precursor in step (4) is 300-500°C, and the calcination time is 2-5h. Compared with the calcination temperature of the additive precursor component, the calcination temperature of the catalyst precursor is lower, which is beneficial to maintain the content of the element with high activity corresponding to the valence state in the active component, and improve the denitration catalytic activity of the catalyst under low temperature conditions. The embodiments of the present invention and the comparative examples show the catalytic effects of the catalysts obtained by calcining different catalyst precursors at different temperatures.

[0036] In a further example of the present invention, the sources of manganese source, iron source, strontium source, zirconium source and lanthanum source are optimized. Optionally, the zirconium source includes one or both of zirconium nitrate and zirconium chloride. Optionally, the lanthanum source includes one or both of lanthanum nitrate and lanthanum chloride. Optionally, the manganese source includes at least one of manganese acetate, manganese nitrate and manganese sulfate. The iron source includes at least one of ferric nitrate, ferric sulfate and ferric chloride. In the actual process, those skilled in the art can select as needed.

[0037] On the other hand, the present invention provides a manganese-based multi-element ultra-low temperature denitration catalyst, which is prepared by the above-mentioned preparation method of the manganese-based multi-element ultra-low temperature denitration catalyst.

[0038] On the other hand, the present invention proposes a manganese-based multi-element ultra-low temperature denitrification catalyst, characterized in that the molar ratio of manganese, iron, strontium, zirconium and lanthanum in the catalyst, calculated as metal elements, is 60:(10-40):(2-20):(3-14):(1-10), preferably 60:(20-30):(3-17):(5-10):(1-8).

[0039] On the other hand, the present invention proposes the use of the above manganese-based multi-element ultra-low temperature denitration catalyst in NH3-SCR. The manganese-based multi-element ultra-low temperature denitration catalyst of the present invention exhibits excellent NOx denitration catalytic activity under the condition of ≤150°C, and has important practical application value.

[0040] Compared with the prior art, the beneficial effects of the present invention are as follows: the preparation method of the manganese-based multi-component ultra-low temperature denitrification catalyst of the present invention uses manganese and iron as active components, and uses strontium, zirconium and lanthanum as catalyst additives, thereby improving the catalytic performance of the prepared catalyst; a precipitation-impregnation method is used in the preparation process of the catalyst, and the overall process adopts step-by-step calcination of an additive precursor and a catalyst precursor, and combines an organic solvent, a dispersant and an initial ultrasonic treatment in the precipitation process, and uses intermittent ultrasonic treatment in the impregnation process to uniformly impregnate the active elements inside and outside the catalyst additive; the manganese-based multi-component ultra-low temperature denitrification catalyst prepared by the catalyst preparation method of the present invention has abundant pores, a large specific surface area, and the active substances and the additive elements are evenly dispersed, and has excellent ultra-low catalytic temperature activity. BRIEF DESCRIPTION OF THE DRAWINGS

[0041] The drawings constituting a part of the present application are used to provide a further understanding of the present invention. The exemplary embodiments of the present invention and their descriptions are used to explain the present invention and do not constitute an improper limitation of the present invention. In the drawings:

[0042] Figure 1 The electron microscope morphology of the manganese-based multi-element ultra-low temperature denitration catalyst prepared in Example 9 of the present invention is shown;

[0043] Figure 2 The electron microscope morphology of the manganese-based multi-element denitration catalyst prepared in Comparative Example 5 is shown;

[0044] Figure 3 The electron microscope morphology of the manganese-based multi-component denitration catalyst prepared in Comparative Example 9 is shown. DETAILED DESCRIPTION

[0045] In order to facilitate the understanding of the present invention, the present invention will be described more comprehensively below, and preferred embodiments of the present invention are given. However, it should be understood that these embodiments are only used for more detailed description and should not be understood as limiting the present invention in any form, i.e., not intended to limit the scope of protection of the present invention.

[0046] Unless otherwise defined, the technical terms used in the following examples have the same meanings as those generally understood by those skilled in the art to which the present invention belongs. The test reagents used in the following examples, unless otherwise specified, are all conventional biochemical reagents; the experimental methods, unless otherwise specified, are all conventional methods.

[0047] The specific surface area of ​​the catalyst was obtained by N2 adsorption and desorption treatment: the specific surface area of ​​the catalyst sample was measured on the BELSORP-Mini II of Maiqikebaier. The sample was vacuum pretreated at 200°C for 10 hours before testing, and the adsorption isotherm was measured at -196°C liquid nitrogen temperature during the test; the surface area was then calculated using the BET model.

[0048] Example 1

[0049] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method comprising:

[0050] (1) Using strontium source, zirconium source and lanthanum source as catalyst promoters, 5.4g of strontium chloride hexahydrate, 20.3g of zirconium nitrate pentahydrate and 2.92g of lanthanum nitrate hexahydrate were dissolved in 1000ml of deionized water according to the molar ratio of metal elements of 3:7:1 to form a promoter precursor solution, and then n-propanol with a volume of about 30% of the volume of the precursor solution was added as an organic solvent, and then 1% polyacrylamide corresponding to the mass of the corresponding promoter oxide was added as a dispersant, and after continuous stirring and mixing, anhydrous sodium carbonate solution was slowly added dropwise to perform precipitation reaction until the pH was 10, and then ultrasonic power of 40w was used for 1h, and the ultrasonic temperature was set to 70℃, and stirring was performed at the same time to form a suspended promoter precursor;

[0051] (2) The catalyst promoter precursor was washed with ethanol for 3 times and deionized water for 3 times, then filtered, dried at 100° C. for 12 h, calcined in a muffle furnace at 900° C. for 6 h, and fully ground to obtain the catalyst promoter corresponding oxide powder;

[0052] (3) adding 68.4 g of manganese sulfate monohydrate, 68.2 g of ferric nitrate nonahydrate and the corresponding oxide powder of the catalyst promoter in a ratio of 60:25 of the metal element mole ratio to 1000 ml of deionized water, and performing intermittent ultrasonication for 2 cycles for 4 times at a mode of 80 W ultrasonication for 1 h and stopping for 20 min, and then standing for 10 h to obtain a catalyst precursor;

[0053] (4) After the catalyst precursor has been allowed to stand for 12 hours, it is filtered and separated, and then baked at 100° C. for 12 hours, and calcined in a muffle furnace at 300° C. for 3 hours to obtain a finished manganese-based multi-element ultra-low temperature denitrification catalyst, wherein the molar ratio of the manganese source, iron source, strontium source, zirconium source and lanthanum source is 60:25:3:7:1.

[0054] Example 2

[0055] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source is 8:7:1 based on the metal elements.

[0056] Example 3

[0057] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in the step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source is 8:7:1 in terms of metal elements; the power of the ultrasound in the step (1) is 80W and the duration is 3h.

[0058] Example 4

[0059] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in the step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source is 8:7:1 in terms of metal elements; the power of the ultrasound in the step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in the step (2) is 1100°C.

[0060] Example 5

[0061] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source in terms of metal elements is 12:7:1; the power of the ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0062] Example 6

[0063] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source in terms of metal elements is 12:7:1; the power of the ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 600°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0064] Example 7

[0065] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source in terms of metal elements is 12:7:1; the power of the ultrasound in step (1) is 80W, the duration is 3h, and n-butanol is used as the organic solvent; and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; and the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0066] Example 8

[0067] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of strontium source, zirconium source and lanthanum source in terms of metal elements is 12:7:1; the organic solvent used in step (1) is n-butanol; in addition, the dispersant used is sodium polyacrylate; the power of ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0068] Example 9

[0069] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, which is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of strontium source, zirconium source and lanthanum source in terms of metal elements is 12:7:3; the organic solvent used in step (1) is n-butanol; in addition, the dispersant used is sodium polyacrylate; the power of ultrasound in step (1) is 80w, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100℃; the calcination temperature of the catalyst precursor in step (4) is 350℃. The specific surface area of ​​the catalyst prepared in this example is 236m 2 / g, its electron microscope morphology is as follows Figure 1 .Depend on Figure 1 It can be seen that the catalyst prepared in this embodiment has a regular morphology, abundant and evenly dispersed pores, and the catalyst active element particles and auxiliary agent particles of different particle sizes are adhered to each other to form a nanochain structure, and the particles of each element are evenly dispersed.

[0070] Example 10

[0071] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source in terms of metal elements is 12:7:7; the organic solvent used in step (1) is n-butanol; in addition, the dispersant used is sodium polyacrylate; the power of ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0072] Embodiment 11

[0073] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source in terms of metal elements is 12:7:7; the organic solvent used in step (1) is n-butanol; in addition, the dispersant used is sulfonated polystyrene; the power of ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0074] Example 12

[0075] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method is the same as the preparation method shown in Example 1, except that: in step (1), the molar ratio of strontium source, zirconium source and lanthanum source in terms of metal elements is 14:7:7; the organic solvent used in step (1) is propylene glycol; in addition, the dispersant used is sulfonated polystyrene; the power of ultrasound in step (1) is 80W, the duration is 3h, and the calcination temperature of the auxiliary agent precursor in step (2) is 1100°C; the calcination temperature of the catalyst precursor in step (4) is 350°C.

[0076] Embodiment 13

[0077] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method comprising the following steps:

[0078] (1) Using strontium source, zirconium source and lanthanum source as catalyst promoters, 36g of strontium chloride hexahydrate, 8.7g of zirconium nitrate pentahydrate and 29.2g of lanthanum nitrate hexahydrate were dissolved in 1000ml of deionized water according to the molar ratio of metal elements of 20:3:10 to form a promoter precursor solution, and then n-butanol with a volume of about 20% of the volume of the precursor solution was added as an organic solvent, and then sodium polyacrylate corresponding to 0.3% of the mass of the corresponding promoter oxide was added as a dispersant, and after continuous stirring and mixing, anhydrous sodium carbonate solution was slowly added dropwise to perform precipitation reaction until the pH was 10, and then ultrasonicated at a power of 80w for 3h, the ultrasonic temperature was set to 70°C, and stirring was performed at the same time to form a suspended promoter precursor;

[0079] (2) The additive precursor was washed with ethanol for 3 times and deionized water for 3 times, then filtered, dried at 100° C. for 12 h, calcined in a muffle furnace at 1100° C. for 6 h, and fully ground to obtain the oxide powder corresponding to the catalyst additive;

[0080] (3) adding 68.4 g of manganese sulfate monohydrate, 27.2 g of ferric nitrate nonahydrate and the corresponding oxide powder of the catalyst promoter in a ratio of 60:10 of the metal element molar ratio to 1000 ml of deionized water, and performing intermittent ultrasonication for 2 cycles for 4 times at a mode of 80 W ultrasonication for 1 h and stopping for 20 min, and then standing for 10 h to obtain a catalyst precursor;

[0081] (4) After the catalyst precursor has been allowed to stand, it is filtered and separated, dried at 100° C. for 12 h, and calcined in a muffle furnace at 350° C. for 3 h to obtain a finished manganese-based multi-element ultra-low temperature denitrification catalyst.

[0082] Embodiment 14

[0083] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method comprising the following steps:

[0084] (1) Using strontium source, zirconium source and lanthanum source as catalyst promoters, 36g of strontium chloride hexahydrate, 14.5g of zirconium nitrate pentahydrate and 23.4g of lanthanum nitrate hexahydrate were dissolved in 1000ml of deionized water according to the molar ratio of metal elements of 20:5:8 to form a promoter precursor solution, and then n-butanol with a volume of about 20% of the volume of the precursor solution was added as an organic solvent, and then sodium polyacrylate corresponding to 1.5% of the mass of the corresponding promoter oxide was added as a dispersant, and after continuous stirring and mixing, anhydrous sodium carbonate solution was slowly added dropwise to perform precipitation reaction until the pH was 10, and then ultrasonicated at a power of 80w for 3h, the ultrasonic temperature was set to 70°C, and stirring was performed at the same time to form a suspended promoter precursor;

[0085] (2) The additive precursor was washed with ethanol for 3 times and deionized water for 3 times, then filtered, dried at 100° C. for 12 h, calcined in a muffle furnace at 1100° C. for 6 h, and fully ground to obtain the oxide powder corresponding to the catalyst additive;

[0086] (3) adding 68.4 g of manganese sulfate monohydrate, 54.5 g of ferric nitrate nonahydrate and the corresponding oxide powder of the catalyst promoter in a ratio of 60:20 of the metal elements into 1000 ml of deionized water, and performing intermittent ultrasonication for 2 cycles for 4 times in a mode of ultrasonication at 80 W for 1 h and stopping for 20 min, and then standing for 10 h to obtain a catalyst precursor;

[0087] (4) After the catalyst precursor has been allowed to stand, it is filtered and separated, dried at 100° C. for 12 h, and calcined in a muffle furnace at 350° C. for 3 h to obtain a finished manganese-based multi-element ultra-low temperature denitrification catalyst.

[0088] Embodiment 15

[0089] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method comprising the following steps:

[0090] (1) Using strontium source, zirconium source and lanthanum source as catalyst promoters, 30.6g of strontium chloride hexahydrate, 28.9g of zirconium nitrate pentahydrate and 29.2g of lanthanum nitrate hexahydrate were dissolved in 1000ml of deionized water according to the molar ratio of metal elements of 17:10:10 to form a promoter precursor solution, and then n-butanol with a volume of about 50% of the volume of the precursor solution was added as an organic solvent, and then sodium polyacrylate corresponding to 0.5% of the mass of the corresponding promoter oxide was added as a dispersant, and after continuous stirring and mixing, anhydrous sodium carbonate solution was slowly added dropwise to perform precipitation reaction until the pH was 10, and then ultrasonicated at a power of 80w for 3h, the ultrasonic temperature was set to 70°C, and stirring was performed at the same time to form a suspended promoter precursor;

[0091] (2) The additive precursor was washed with ethanol for 3 times and deionized water for 3 times, then filtered, dried at 100° C. for 12 h, calcined in a muffle furnace at 1100° C. for 6 h, and fully ground to obtain the oxide powder corresponding to the catalyst additive;

[0092] (3) adding 68.4 g of manganese sulfate monohydrate, 81.7 g of ferric nitrate nonahydrate and the corresponding oxide powder of the catalyst promoter in a molar ratio of 60:30 of the metal elements into 1000 ml of deionized water, and performing intermittent ultrasonication for 2 cycles for 4 times in a mode of 80 W ultrasonication for 1 h and stopping for 20 min, and then standing for 10 h to obtain a catalyst precursor;

[0093] (4) After the catalyst precursor has been allowed to stand, it is filtered and separated, dried at 100° C. for 12 h, and calcined in a muffle furnace at 350° C. for 3 h to obtain a finished manganese-based multi-element ultra-low temperature denitrification catalyst.

[0094] Example 16

[0095] A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, the method comprising the following steps:

[0096] (1) Using strontium source, zirconium source and lanthanum source as catalyst promoters, 3.6g of strontium chloride hexahydrate, 40.5g of zirconium nitrate pentahydrate and 23.4g of lanthanum nitrate hexahydrate were dissolved in 1000ml of deionized water according to the molar ratio of metal elements of 2:14:8 to form a promoter precursor solution, and then n-butanol with a volume of about 50% of the volume of the precursor solution was added as an organic solvent, and then sodium polyacrylate corresponding to 0.3% of the mass of the corresponding promoter oxide was added as a dispersant, and after continuous stirring and mixing, anhydrous sodium carbonate solution was slowly added dropwise to perform precipitation reaction until the pH was 11, and then ultrasonicated at a power of 80w for 3h, the ultrasonic temperature was set to 70°C, and stirring was performed at the same time to form a suspended promoter precursor;

[0097] (2) The additive precursor was washed with ethanol for 3 times and deionized water for 3 times, then filtered, dried at 100° C. for 12 h, calcined in a muffle furnace at 1100° C. for 6 h, and fully ground to obtain the oxide powder corresponding to the catalyst additive;

[0098] (3) adding 68.4 g of manganese sulfate monohydrate, 109.4 g of ferric nitrate nonahydrate and the corresponding oxide powder of the catalyst promoter in a ratio of 60:40 of the metal elements into 1000 ml of deionized water, and performing intermittent ultrasonication for 2 cycles for 4 times in a mode of 80 W ultrasonication for 1 h and stopping for 20 min, and then standing for 10 h to obtain a catalyst precursor;

[0099] (4) After the catalyst precursor has been allowed to stand, it is filtered and separated, dried at 100° C. for 12 h, and calcined in a muffle furnace at 350° C. for 3 h to obtain a finished manganese-based multi-element ultra-low temperature denitrification catalyst.

[0100] Comparative Example 1

[0101] A method for preparing a manganese-based multi-component denitration catalyst is the same as the preparation method shown in Example 1, except that no strontium source is added in this comparative example.

[0102] Comparative Example 2

[0103] A method for preparing a manganese-based multi-component denitration catalyst is the same as the preparation method shown in Example 2, except that a cerium source is used instead of a lanthanum source in this comparative example.

[0104] Comparative Example 3

[0105] A method for preparing a manganese-based multi-component denitration catalyst is the same as the preparation method shown in Example 3, except that the power of the ultrasonic treatment in step (1) of this comparative example is 160W and the ultrasonic time is 5h.

[0106] Comparative Example 4

[0107] A method for preparing a manganese-based multi-component denitration catalyst is the same as the preparation method shown in Example 4, except that in step (3) of this comparative example, continuous ultrasonic treatment is used for 4 hours.

[0108] Comparative Example 5

[0109] A method for preparing a manganese-based multi-component denitration catalyst, which is the same as the preparation method shown in Example 7, except that the calcination temperature of the catalyst precursor in this comparative example is 600°C; the specific surface area of ​​the prepared catalyst is 82m 2 / g; The electron microscopic morphology of the catalyst prepared in this comparative example is as follows Figure 2 As shown. Figure 2 It can be seen that the large deposits and attached particles formed by the agglomeration of active elements of the catalyst should be formed by the adhesion of particles with smaller particle sizes, and the surface morphology is rough; the surface of the catalyst is seriously agglomerated, the element particles formed are of different sizes, and lack a pore structure; combined with the specific surface area test, the specific surface area of ​​the catalyst is small, which is consistent with the characteristics of the SEM image.

[0110] Comparative Example 6

[0111] A method for preparing a manganese-based multi-component denitration catalyst, which is the same as the preparation method shown in Example 12, except that the calcination temperature of the auxiliary agent precursor in this comparative example is 1300°C.

[0112] Comparative Example 7

[0113] A method for preparing a manganese-based multi-component denitration catalyst, which is the same as the preparation method shown in Example 12, except that the power of the ultrasonic treatment in step (1) of this comparative example is 160W and the ultrasonic time is 5h.

[0114] Comparative Example 8

[0115] A method for preparing a manganese-based multi-component denitrification catalyst, the method is the same as the preparation method shown in Example 8, except that in step (1), the molar ratio of the strontium source, the zirconium source and the lanthanum source is 12:7:1 in terms of metal elements; and in this comparative example, no organic solvent is added in step (1), but is replaced by an equal amount of deionized water, and no dispersant is added in (1).

[0116] Comparative Example 9

[0117] A method for preparing a manganese-based multi-element denitration catalyst, compared with Example 11, this method uses a one-step coprecipitation to prepare the catalyst, and the one-step calcination temperature is 1100°C. The electron microscopic morphology of the catalyst prepared in this comparative example is as follows Figure 3 ;Depend on Figure 3It can be seen that the catalyst is composed of large aggregates formed by the aggregation of active elements and irregular nanoparticles adhered on the surface. The surface of the aggregates is smooth, and the lighter-colored particles are adhered and embedded. In addition, the catalyst is severely agglomerated and lacks a pore structure. The element particles formed are of different sizes, and the components are unevenly dispersed. Its specific surface area is small, which is 119m 2 / g, which verifies the necessity of selecting the step-by-step precipitation and calcination method in the embodiment.

[0118] Test Case

[0119] This test example evaluates the catalytic performance of the manganese-based multi-element ultra-low temperature denitration catalysts prepared in Examples 1-12 and the manganese-based multi-element denitration catalysts prepared in Comparative Examples 1-9, specifically:

[0120] The performance evaluation temperature range is: 50-150℃, the simulated flue gas flow rate is 1240ml / min, and the amount of catalyst used in the test is 2cm 3 , 450ppm NO, 500ppm NH3, 6% O2, using N2 as the filling gas. The volume space velocity is about 37000h -1 , NO in the outlet exhaust X The components were detected by using electrochemical sensors to record the NOx concentration in the simulated flue gas before and after introduction.

[0121] The denitrification activity was evaluated based on the NOx conversion rate. X The conversion rate is calculated according to the following formula:

[0122] η==×100%

[0123] Where η: conversion rate of catalyst;

[0124] :NO in simulated flue gas before catalysis X Volume concentration;

[0125] :NO in simulated flue gas after catalysis X Volume concentration.

[0126] The test results are shown in Table 1.

[0127] Table 1

[0128]

[0129]

[0130] Combining Test Example 1 with Comparative Test Example 1, it can be confirmed that the low-temperature catalytic activity of the catalyst prepared in Example 1, which introduces strontium source, zirconium source and lanthanum source as the auxiliary element of the catalyst of the present invention, is better than the catalytic activity of the catalyst prepared in Comparative Example 1, which does not introduce strontium source as the auxiliary element, and the overall NO is better.X Conversion rate; further combined with Test Example 2 and Comparative Test Example 2, it can be verified that the catalyst prepared in Example 2, which introduces a lanthanum source, has better denitration catalyst performance under ultra-low temperature conditions than the catalyst prepared in Comparative Example 2, which introduces a precious metal cerium. Therefore, the preparation method of the manganese-based multi-element ultra-low temperature denitration catalyst of the present invention improves the catalytic activity of the prepared catalyst by setting an auxiliary element including a strontium source, a zirconium source and a lanthanum source, and the introduction effect of the precious metal lanthanum element is better than the introduction of the precious metal cerium element under the catalyst preparation system of the present invention.

[0131] It can be seen from Test Example 3 and Comparative Test Example 3 that the catalyst prepared in Example 3 has a NO X The conversion rate is better than that of the ultra-low temperature catalytic NO obtained by the catalyst prepared in Comparative Example 3. X The conversion rate confirms that the first ultrasonic treatment of the material after the precipitation reaction under appropriate ultrasonic power and time conditions during the preparation of the catalyst in Example 3 of the present invention improves the catalytic activity of the prepared catalyst. Based on the catalyst effect of Comparative Example 3, it can be inferred that excessive ultrasound may cause a decrease in catalyst performance due to reasons such as destroying the catalyst structure or causing agglomeration.

[0132] Combining Test Example 4 with Comparative Test Example 4, it can be confirmed that in the preparation process of the manganese-based multi-element ultra-low temperature denitrification catalyst in Example 4, intermittent ultrasound is carried out during the impregnation of the auxiliary active components, so that the ultra-low temperature catalytic activity of the prepared catalyst is better than that of the catalyst prepared in Comparative Example 4 with continuous ultrasound. It is speculated that the intermittent ultrasound in step (3) of the present invention is beneficial to maintaining the pore structure inside the catalyst, thereby facilitating the impregnation of active elements into the inside and outside of the precursor and promoting the uniform dispersion of the elements; moderate intermittent ultrasound treatment can promote the full dispersion of the active components of the catalyst, increase the specific surface area, increase the active sites and show a better catalytic effect.

[0133] By combining test example 7 with comparative test example 5 and Figure 2 It can be verified that in the preparation of the manganese-based multi-element ultra-low temperature denitration catalyst of the present invention, the catalyst precursor is calcined at a suitable temperature in step (4), so that the ultra-low temperature denitration catalytic activity of the prepared catalyst is significantly better than the ultra-low temperature catalytic activity of the catalyst prepared by using comparative example 5, while the catalyst of comparative example 5 uses a higher temperature to calcine the catalyst precursor; it is speculated that if the calcination temperature of the active element in step (4) of the present invention is too high, on the one hand, it leads to a reduction in high-activity valence state catalysts, and on the other hand, the higher temperature may also cause the active components and additives to form agglomerations, blocking the catalyst pore structure.

[0134] It can be seen from Test Example 12 and Comparative Examples 6 and 7 that the catalyst prepared by calcining the auxiliary agent precursor at a suitable temperature in step (2) of Example 12 of the present invention is significantly more catalytically active than the technical solution of calcining the auxiliary agent precursor at a higher temperature in Comparative Example 6 or Comparative Example 7, showing a higher NO under ultra-low temperature catalytic conditions. X The conversion rate was 2.34%, which confirmed that the calcination of the auxiliary agent precursor under appropriate temperature conditions in the catalyst preparation method of the present invention can effectively improve the denitration catalytic activity of the prepared catalyst under ultra-low temperature conditions.

[0135] Combining Test Example 8 with Comparative Example 8, it can be seen that in the preparation method of Example 8 of the present invention, a dispersant and an organic solvent are added in step (1). Compared with the preparation method of Comparative Example 8 in which no dispersant and organic solvent are added, the NO X The conversion rate is better than that of NO in Comparative Example 8. X The conversion rate of NO at 100℃, 125℃ and 150℃ X The conversion rate reached 100%, which confirmed that in the manganese-based multi-element ultra-low temperature denitration catalyst preparation system of the present invention, adding a dispersant and an organic solvent during the preparation of the auxiliary agent precursor can regulate the catalyst preparation process to improve the catalyst performance.

[0136] From Test Example 11 and Comparative Example 9, Figure 3 It can be verified that when the catalyst is prepared by the conventional one-step co-precipitation method (Comparative Example 9), the active component and the auxiliary component are calcined at a relatively high calcination temperature. Although the auxiliary component is fully decomposed, the content of the high-activity valence catalyst is reduced; and the high temperature causes the active component and the auxiliary component to form agglomerates, blocking the catalyst pore structure. The catalyst preparation method in Example 11 of the present invention adopts a step-by-step calcination method, which can promote the catalyst auxiliary and the active group to be fully decomposed and activated, respectively. The catalytic performance of the prepared catalyst is significantly better than that of the catalyst prepared by the co-precipitation method, and the performance of low-temperature catalytic NOx denitrification is more excellent.

[0137] It should be noted that the above contents are further detailed descriptions of the present invention in combination with specific implementation methods, and it cannot be determined that the specific implementation of the present invention is limited to these descriptions. For ordinary technicians in the technical field to which the present invention belongs, several simple improvements can be made without departing from the concept of the present invention, which should be regarded as falling within the scope of protection of the present invention.

Claims

1. A method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst, characterized in that: The following steps are involved: (1) adding an organic solvent and a dispersant to an additive precursor solution containing a strontium source, a zirconium source, and a lanthanum source, mixing them evenly, and then adding a precipitant to perform a precipitation reaction. After the reaction is completed, the material is subjected to a first ultrasonic treatment to obtain an additive precursor; (2) the promoter precursor is calcined to obtain the catalyst promoter corresponding oxide; (3) dispersing a manganese source, an iron source and the corresponding oxide of the catalyst promoter in pure water or deionized water, and subjecting the mixture to intermittent ultrasonic treatment and aging treatment to obtain a catalyst precursor; (4) The catalyst precursor is calcined at low temperature to obtain the manganese-based multi-element ultra-low temperature denitrification catalyst.

2. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The catalyst is calculated based on metal elements, and the molar ratio of manganese source, iron source, strontium source, zirconium source and lanthanum source is 60:(10-40):(2-20): (3-14):(1-10), preferably 60:(20-30):(3-17):(5-10):(1-8).

3. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The organic solvent includes at least one of n-butanol, n-propanol and glycerol; Preferably, the amount of the organic solvent added is 20%-50% of the auxiliary agent precursor in step (1).

4. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The dispersant includes at least one of sulfonated polystyrene, sodium polyacrylate, and polyacrylamide; Preferably, the amount of the dispersant added is 0.3%-2.0% of the mass of the oxide corresponding to the catalyst promoter in step (2), preferably 0.5%-1.5%.

5. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The precipitant includes an aqueous solution of an alkaline carbonate; Preferably, the alkaline carbonate includes at least one of sodium carbonate, potassium carbonate, sodium bicarbonate, potassium bicarbonate, ammonium carbonate and ammonium bicarbonate.

6. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The pH value of the material after the precipitation reaction in step (1) is 9-11; And / or, the temperature of the first ultrasonic treatment in step (1) is 60-80°C, the power is 40w-240w, and the duration is 2-5h; And / or, in the step (2), the temperature of calcining the auxiliary agent precursor is 600-1200° C., and the calcining time is 3-8 hours.

7. The method for preparing a manganese-based multi-element ultra-low temperature denitration catalyst according to claim 1, characterized in that: The power of intermittent ultrasound in step (3) is 50-100w, each ultrasound is for 30-90min, and then stopped for 15-25min, and the intermittent treatment is repeated 3-5 times; And / or, the aging treatment temperature is 15-30°C and the treatment time is 5-10h; And / or, in step (4), the calcination temperature of the catalyst precursor is 300-500° C., and the calcination time is 2-5 hours.

8. A manganese-based multi-element ultra-low temperature denitration catalyst, characterized in that: The manganese-based multi-component ultra-low temperature denitration catalyst is prepared by the preparation method of the manganese-based multi-component ultra-low temperature denitration catalyst according to any one of claims 1 to 7.

9. A manganese-based multi-element ultra-low temperature denitration catalyst, characterized in that: The catalyst has a molar ratio of manganese, iron, strontium, zirconium and lanthanum in terms of metal elements of 60:(10-40):(2-20):(3-14):(1-10), preferably 60: (20-30)：(3-17)：(5-10)：(1-8)。 10. Use of the manganese-based multi-element ultra-low temperature denitration catalyst according to claim 8 or 9 in NH3-SCR.

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