A nano-synapse structure low-temperature rare earth-based denitration catalyst, a preparation method and application thereof

Abstract

The application discloses a preparation method and application of a nanosynaptic structure low-temperature rare earth-based denitration catalyst, and the catalyst takes titanium dioxide with a nanosynaptic structure as a carrier, takes a composite oxide of cerium dioxide and yttrium oxide as an active component, takes a composite oxide of praseodymium oxide and samarium oxide as a cocatalyst, takes aluminum oxide as a synapse forming agent, and takes succinic acid as a morphology control agent, and is prepared by using a low-temperature hydrothermal-alkali liquor etching-impregnation loading combined method. The catalyst synthesized by the method has the advantages of a large specific surface area, sufficient exposure of active sites, strong resistance to water and sulfur poisoning, and the like, and can realize the ultra-low emission target of nitrogen oxides under the low-temperature flue gas working condition of the steel sintering industry.

Description

TECHNICAL FIELD

[0001] The application relates to a preparation method and application of a nanosynapse structure low-temperature rare earth-based denitration catalyst, and belongs to the field of industrial flue gas purification. BACKGROUND

[0002] The steel sintering process is one of important links in steel production, and nitrogen oxides (NO x ) discharged by the steel sintering process is one of main sources of air pollution. The NO x gas not only is a formation material of acid rain, but also is harmful to human health and can cause respiratory system diseases and other environmental problems. With increasingly strict environmental protection policies, more and more countries and regions in the world have set more stringent standards for industrial emissions, especially emissions of NO x . For example, developed countries such as Europe and the United States and China have gradually increased the requirements of environmental regulations and standards for heavy industries such as steel and metallurgy in recent years.

[0003] The steel sintering is a process of heating and fusing iron ore powder and other raw materials (such as coke, limestone, etc.) at high temperature. There are usually various oxidation and reduction reactions in the sintering furnace, and the generation of NO x is closely related to factors such as fuel combustion, mineral raw material reaction and temperature distribution in the furnace. In the sintering process, the emission of NO x mainly comes from high-temperature combustion of fuel, especially in the stage with higher temperature. The traditional selective catalytic reduction (SCR) technology usually needs a higher reaction temperature (300-400 DEG C), and the exhaust gas temperature of the steel sintering process is generally between 180-300 DEG C, which is usually lower than the optimal working temperature of the SCR catalyst.

[0004] In order to achieve effective NO x control in the steel sintering industry, it is urgent to develop a denitration catalyst capable of working efficiently at a lower temperature (lower than 200 DEG C). However, the existing SCR catalyst has certain deficiencies in NO x conversion efficiency in a low-temperature environment, and sulfur dioxide and water and ammonia gas can react to generate ammonium bisulfate to cover the catalytically active sites, causing the catalytic activity to decrease, and water can also condense on the surface of the catalyst to reduce the mechanical strength of the catalyst. Therefore, research and development of a low-temperature denitration catalyst with strong resistance to combined poisoning is one of important directions of research in the steel sintering industry. SUMMARY

[0005] The purpose of the present application is to propose a preparation method and application of a nanosynapse structure low-temperature rare earth-based denitration catalyst in view of the current situation and existing problems of insufficient catalytic activity and resistance to poisoning of the existing low-temperature denitration catalyst for flue gas in the steel sintering industry.

[0006] The nanosynaptic structure low-temperature rare earth-based denitration catalyst is characterized in that: the catalyst takes titanium dioxide with a nanosynaptic structure as a carrier, takes a composite oxide of cerium dioxide and yttrium oxide as an active component, takes a composite oxide of praseodymium oxide and samarium oxide as a cocatalyst, takes aluminum oxide as a synapse forming agent, and takes succinic acid as a morphology control agent, and is prepared by using a low-temperature hydrothermal-alkali solution etching-impregnation loading combined method; the mass percentage content of the active component is 20-40% based on the mass of the carrier, the mass percentage content of the cocatalyst is 1-5%, and the mass ratio of cerium dioxide to yttrium oxide in the active component is 1:(0.2-0.5), and the mass ratio of praseodymium oxide to samarium oxide in the cocatalyst is 1:(0.5-2).

[0007] The preparation method of the catalyst is as follows:

[0008] (1) preparing an aluminum-titanium composite oxide carrier by a low-temperature hydrothermal method

[0009] The titanium salt, the aluminum salt, the succinic acid and the deionized water are uniformly mixed, and then are placed in a hydrothermal reaction kettle for low-temperature hydrothermal reaction; after the reaction is completed, the aluminum-titanium composite oxide carrier is obtained by filtering, drying and calcining;

[0010] (2) preparing a titanium dioxide carrier with a nanosynaptic structure by an alkali solution etching method

[0011] The sodium hydroxide is weighed and dissolved in deionized water to form an alkali solution, and then the aluminum-titanium composite oxide carrier prepared in step (1) is placed in the alkali solution, and is subjected to water bath heating reaction; then the titanium dioxide carrier with a nanosynaptic structure is obtained by filtering, acid washing with a dilute hydrochloric acid solution and washing with deionized water three times respectively, and drying;

[0012] (3) preparing the catalyst by an impregnation loading method

[0013] The cerium salt, the yttrium salt, the praseodymium salt, the samarium salt and the deionized water are uniformly mixed to obtain a composite precursor solution, and then the titanium dioxide carrier with a nanosynaptic structure obtained in step (2) is placed in the composite precursor solution; the mixed solution is dried in an oven, and finally the nanosynaptic structure low-temperature rare earth-based denitration catalyst is obtained by calcining in a muffle furnace.

[0014] In the technical scheme of the present application: the titanium salt in step (1) is tetrabutyl titanate or tetraethyl titanate, the aluminum salt is aluminum chloride or aluminum nitrate, and the mass ratio of the titanium salt, the aluminum salt, the succinic acid and the deionized water is 1:(0.5-1):(0.3-0.5):(30-60).

[0015] In the technical scheme of the present application: the temperature of the low-temperature hydrothermal reaction in step (1) is 110-130℃, the time of the low-temperature hydrothermal reaction is 6-12h, the drying temperature is 80-100℃, the drying time is 6-12h, the calcining temperature is 500-600℃, and the calcining time is 2-4h.

[0016] In the technical scheme of the present application, the mass ratio of sodium hydroxide, deionized water and aluminum-titanium composite oxide carrier in step (2) is 1:(10-20):(0.1-0.3).

[0017] In the technical scheme of the present application, the temperature of water bath heating in step (2) is 50-70 DEG C, the time of water bath heating is 3-6h, the temperature of drying is 80-100 DEG C, and the time of drying is 6-12h.

[0018] In the technical scheme of the present application, the dilute hydrochloric acid solution in step (2) is a hydrochloric acid solution with a mass fraction of 5-10%, the mass ratio of dilute hydrochloric acid solution and aluminum-titanium composite oxide carrier is 1:(0.1-0.2), and the mass ratio of deionized water and aluminum-titanium composite oxide carrier is 1:(0.1-0.2).

[0019] In the technical scheme of the present application, the cerium salt in step (3) is cerium nitrate hexahydrate or cerium chloride, the yttrium salt is yttrium nitrate hexahydrate or yttrium chloride, the praseodymium salt is praseodymium nitrate hexahydrate or praseodymium chloride, the samarium salt is samarium nitrate hexahydrate or samarium chloride, and the mass ratio of cerium salt and deionized water is 1:(20-40).

[0020] In the technical scheme of the present application, the temperature of drying in step (3) is 80-100 DEG C, the time of drying is 3-6h, the temperature of calcination is 500-600 DEG C, and the time of calcination is 3-6h.

[0021] In the technical scheme of the present application, the above-mentioned catalyst is applied in low-temperature denitration in the steel sintering industry.

[0022] In the catalyst activity evaluation experiment of the present application, 1mL of catalyst with a mesh size of 20-40 is poured into a quartz tube with an inner diameter of 6mm, and is fixed by quartz wool and iron wire, and the quartz tube is placed in a tube furnace, and the actual temperature of the catalytic reaction is adjusted by controlling the heating temperature of the tube furnace. The gas inlet components are NO (500ppm), NH3 (500ppm), O2 (11vol.%), SO2 (200ppm), H2O (5vol.%), and the rest is N2, the total gas flow is 500mL / min, the control temperature is 100-300 DEG C, and each 50 DEG C stays stable for 30min, the NO concentration is measured by Laoying 3021 type portable carbon emission monitor, and the denitration efficiency of the catalyst in the temperature range of 150-300 DEG C is higher than 90%.

[0023] Beneficial effects:

[0024] (1) In the present application, not only succinic acid is used as a morphology control agent to form nanosphere structure of aluminum-titanium composite oxide carrier, but also alkali solution is used to react and erode alumina, leaving titanium dioxide with nanosynaptic structure; the nanosynaptic structure can not only increase the exposure ratio of active sites and improve the low-temperature catalytic activity, but also has hydrophobicity, avoiding water molecules from condensing on the surface of the catalyst, thereby inhibiting the generation and coverage of ammonium bisulfate on the surface of the catalyst, and finally enhancing the water and sulfur poisoning resistance of the catalyst;

[0025] (2) In the present application, the composite oxide of cerium oxide and yttrium oxide is used as an active component, wherein the cerium oxide has excellent redox performance and oxygen storage and release performance, and yttrium in the yttrium oxide is trivalent, which can enter the cerium oxide crystal lattice and promote the formation of oxygen vacancies, thereby improving the low-temperature catalytic activity; and praseodymium oxide and samarium oxide not only have the effect of increasing the oxygen vacancy concentration of the catalyst, but also can preferentially react when sulfur dioxide reacts with the active sites, avoiding the sulfur poisoning of the active sites, and synergistically acting with the nanosynaptic structure, thereby making the catalyst have excellent resistance to composite poisoning at low temperature.

[0026] Therefore, the catalyst prepared by the present application not only has excellent low-temperature flue gas denitrification performance, but also has the advantages of environmental friendliness, simple preparation process, low cost, high cost performance, and strong application promotion value. BRIEF DESCRIPTION OF DRAWINGS

[0027] Figure 1 TEM image of the catalyst prepared in Example 1;

[0028] Figure 2 TEM image of the catalyst prepared in Comparative Example 1;

[0029] Figure 3 TEM image of the catalyst prepared in Comparative Example 2;

[0030] Figure 4 NO removal performance diagram of the catalyst prepared in Examples 1-3 and Comparative Examples 1-2. DETAILED DESCRIPTION

[0031] The present application will be further described below in combination with examples, which are implemented on the premise of the technical scheme of the present application, and detailed implementation modes and specific operation processes are given, but the protection scope of the present application is not limited to the following examples.

[0032] Example 1

[0033] (1) Preparation of aluminum-titanium composite oxide carrier by low-temperature hydrothermal method

[0034] Mixing 5 g of tetrabutyl titanate, 2.5 g of aluminum chloride, 1.5 g of succinic acid and 150 ml of deionized water uniformly, then placing in a hydrothermal reactor to hydrothermal reaction at 110℃ for 6 h, after reaction, filtering and drying at 80℃ for 9 h, after drying, calcining at 500℃ for 2 h to obtain an aluminum-titanium composite oxide carrier;

[0035] (2) Preparation of titanium dioxide carrier with nano synaptic structure by alkali solution etching method

[0036] Weighing 20 g of sodium hydroxide into 200 ml of deionized water to form an alkali solution, then taking 2 g of the aluminum-titanium composite oxide carrier prepared in step (1) and placing it in the alkali solution, then heating in a 50℃ water bath for 3 h, then filtering and washing with 20 g of 5% mass fraction dilute hydrochloric acid solution and 20 ml of deionized water for three times respectively, and finally drying at 80℃ for 6 h to obtain a titanium dioxide carrier with nano synaptic structure;

[0037] (3) Preparation of catalyst by impregnation loading method

[0038] Mixing 0.42 g of cerium nitrate hexahydrate, 0.12 g of yttrium nitrate hexahydrate, 0.017 g of praseodymium nitrate hexahydrate, 0.0085 g of samarium nitrate hexahydrate and 8.4 ml of deionized water uniformly to obtain a composite precursor solution, then taking 1 g of the titanium dioxide carrier with nano synaptic structure obtained in step (2) and placing it in the composite precursor solution, then placing the mixed solution in an oven to dry at 80℃ for 3 h, and finally placing it in a muffle furnace to calcine at 500℃ for 3 h to obtain a nano synaptic structure low-temperature rare earth-based denitration catalyst.

[0039] The mass percentage content of the active component is 20% and the mass percentage content of the catalyst is 1% based on the mass of the carrier, the mass ratio of cerium dioxide and yttrium oxide in the active component is 1:0.2, and the mass ratio of praseodymium oxide and samarium oxide in the catalyst is 1:0.5.

[0040] (4) Catalytic activity test

[0041] Taking 1 mL of the catalyst with a mesh size of 20-40, pouring it into a quartz tube with an inner diameter of 6 mm, fixing it with quartz wool and iron wire, placing the quartz tube in a tube furnace, adjusting the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas composition is: NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), SO2 (200 ppm), H2O (5 vol.%), and the rest is N2. The total gas flow is 500 mL / min. The control temperature is 100-300℃, and each temperature interval of 50℃ stays stable for 30 min. The NO concentration is measured by Laoyang 3021 portable carbon emission monitor. The denitration efficiency of the catalyst is higher than 90% in the temperature range of 150-300℃.

[0042] Example 2

[0043] (1) Preparation of aluminum-titanium composite oxide carrier by low-temperature hydrothermal method

[0044] 5 g of tetraethyl titanate, 3.5 g of aluminum nitrate, 2 g of succinic acid, and 200 ml of deionized water were uniformly mixed, and then placed in a hydrothermal reactor to react at 120°C for 9 h by low-temperature hydrothermal method. After the reaction, it was filtered and dried at 90°C for 9 h. After drying, the aluminum-titanium composite oxide carrier was obtained by calcining at 550°C for 3 h.

[0045] (2) Preparation of titanium dioxide carrier with nano synaptic structure by alkali etching method

[0046] 20 g of sodium hydroxide was dissolved in 300 ml of deionized water to form an alkali solution. Then 4 g of the aluminum-titanium composite oxide carrier prepared in step (1) was placed in the alkali solution, and then heated in a 60°C water bath for 4 h. Then it was filtered and washed with 26 g of 8% mass fraction dilute hydrochloric acid solution and 26 g of deionized water for three times, respectively. Finally, the titanium dioxide carrier with nano synaptic structure was obtained by drying at 90°C for 9 h.

[0047] (3) Preparation of catalyst by impregnation loading method

[0048] 0.31 g of cerium chloride, 0.15 g of yttrium chloride, 0.0022 g of praseodymium chloride, 0.023 g of samarium chloride, and 9.3 ml of deionized water were uniformly mixed to obtain a composite precursor solution. Then 1 g of the titanium dioxide carrier with nano synaptic structure obtained in step (2) was placed in the composite precursor solution. The mixed solution was then dried in an oven at 90°C for 5 h, and finally calcined in a muffle furnace at 550°C for 4 h to obtain the nano synaptic structure low-temperature rare earth-based denitration catalyst.

[0049] Based on the mass of the carrier, the mass percentage of the active component was 30%, and the mass percentage of the catalyst was 3%. The mass ratio of cerium dioxide and yttrium oxide in the active component was 1:0.4, and the mass ratio of praseodymium oxide and samarium oxide in the catalyst was 1:1.

[0050] (4) Test of catalytic activity

[0051] Take 20-40 mesh catalyst 1 mL, pour into the inner diameter of 6 mm quartz tube, with quartz wool and iron wire fixed, the quartz tube is placed in the tube furnace, by controlling the heating temperature of the tube furnace to adjust the actual temperature of the catalytic reaction. The gas composition: NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), SO2 (200 ppm), H2O (5 vol.%), the rest is N2, the total gas flow is 500 mL / min, the control temperature is 100-300℃, each 50℃ stop for 30 min, the NO concentration is measured by Laoying 3021 type portable carbon emission monitor, the denitration efficiency of the catalyst is higher than 90% in the temperature range of 150-300℃.

[0052] Example 3

[0053] (1) Preparation of aluminum-titanium composite oxide carrier by low-temperature hydrothermal method

[0054] Mix 5 g of tetrabutyl titanate, 5 g of aluminum chloride, 2.5 g of succinic acid and 300 ml of deionized water uniformly, then place in a hydrothermal reaction kettle for low-temperature hydrothermal reaction at 130℃ for 12 h, filter after reaction and dry at 100℃ for 12 h, then calcine at 600℃ for 4 h to obtain an aluminum-titanium composite oxide carrier;

[0055] (2) Preparation of titanium dioxide carrier with nano synaptic structure by alkali etching method

[0056] Weigh 20 g of sodium hydroxide into 400 ml of deionized water to form an alkali solution, then take 6 g of the aluminum-titanium composite oxide carrier prepared in step (1) and place it in the alkali solution, then heat it in a 70℃ water bath for 6 h, then filter and wash it with 30 g of 10% dilute hydrochloric acid solution and 30 ml of deionized water for three times respectively, and finally dry it at 100℃ for 12 h to obtain a titanium dioxide carrier with nano synaptic structure;

[0057] (3) Preparation of catalyst by impregnation loading method

[0058] Weigh 0.67 g of cerium nitrate hexahydrate, 0.23 g of yttrium chloride, 0.0426 g of praseodymium nitrate hexahydrate, 0.049 g of samarium chloride, and 26.8 ml of deionized water to obtain a composite precursor solution, then take 1 g of the titanium dioxide carrier with nano synaptic structure obtained in step (2) and place it in the composite precursor solution, then dry the mixed solution in an oven at 100℃ for 6 h, and finally calcine it in a muffle furnace at 600℃ for 6 h to obtain a nano synaptic structure low-temperature rare earth-based denitration catalyst.

[0059] The mass percentage of the active component is 40% and the mass percentage of the cocatalyst is 5% based on the mass of the carrier. The mass ratio of cerium dioxide and yttrium oxide in the active component is 1:0.5, and the mass ratio of praseodymium oxide and samarium oxide in the cocatalyst is 1:2.

[0060] (4) Test of catalytic activity

[0061] Take 1 mL of the catalyst with a mesh size of 20-40, pour it into a quartz tube with an inner diameter of 6 mm, fix it with quartz wool and iron wire, place the quartz tube in a tube furnace, and adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas components are: NO (500 ppm), NH3(500 ppm), O2(11 vol.%), SO2(200 ppm), H2O (5 vol.%), and the rest is N2. The total gas flow is 500 mL / min. The temperature is controlled at 100-300℃, and each 50℃ stays stable for 30 min. The NO concentration is measured by Laoying 3021 portable carbon emission monitor. The denitrification efficiency of the catalyst is higher than 90% in the temperature range of 150-300℃.

[0062] Comparative Example 1

[0063] (1) Preparation of the carrier

[0064] Except that aluminum chloride is not added during the preparation of the catalyst, other conditions are the same as in Example 1.

[0065] (2) Test of catalytic activity

[0066] Take 1 mL of the catalyst with a mesh size of 20-40, pour it into a quartz tube with an inner diameter of 6 mm, fix it with quartz wool and iron wire, place the quartz tube in a tube furnace, and adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas components are: NO (500 ppm), NH3(500 ppm), O2(11 vol.%), SO2(200 ppm), H2O (5 vol.%), and the rest is N2. The total gas flow is 500 mL / min. The temperature is controlled at 100-300℃, and each 50℃ stays stable for 30 min. The NO concentration is measured by Laoying 3021 portable carbon emission monitor. The denitrification efficiency of the catalyst is higher than 90% in the temperature range of 150-300℃.

[0067] (3) Comparison effect

[0068] Compared with Example 1, no aluminum oxide is added as a synapse forming agent in the preparation step (1) of the catalyst, so the reaction of etching aluminum oxide with lye does not occur, and the prepared catalyst is in the form of nanospheres, which reduces the proportion of active sites exposed, thereby reducing the catalytic activity at low temperature.

[0069] Comparative Example 2

[0070] (1) Preparation of catalyst

[0071] Except that succinic acid was not added during the preparation of the catalyst, other conditions were the same as in Example 2.

[0072] (2) Test of catalytic activity

[0073] Take 1 mL of catalyst with a mesh size of 20-40, pour it into a quartz tube with an inner diameter of 6 mm, fix it with quartz wool and iron wire, place the quartz tube in a tube furnace, and adjust the actual temperature of the catalytic reaction by controlling the heating temperature of the tube furnace. The gas composition is: NO (500 ppm), NH3 (500 ppm), O2 (11 vol.%), SO2 (200 ppm), H2O (5 vol.%), and the rest is N2. The total gas flow is 500 mL / min. The temperature is controlled at 100-300℃, and it is kept stable for 30 min every 50℃. The NO concentration is measured by Laoying 3021 portable carbon emission monitor. The denitration efficiency at 150℃ is 42.7%.

[0074] (3) Comparison effect

[0075] Compared with Example 2, the catalyst was not added with a morphology control agent succinic acid during the preparation of the catalyst, which led to the fragmentation of the catalyst morphology, the failure of the alkali solution to erode the alumina to form nano synapse structure, and the great reduction of the exposure ratio of active sites, resulting in the reduction of the denitration activity of the catalyst.

Claims

1. A low-temperature rare-earth-based denitration catalyst with a nanosynaptic structure, characterized in that: The catalyst is prepared by a low-temperature hydrothermal-alkali solution etching-impregnation loading combined method, and has a titanium dioxide carrier with a nanosynaptic structure, a composite oxide of cerium dioxide and yttrium oxide as an active component, a composite oxide of praseodymium oxide and samarium oxide as a cocatalyst, aluminum oxide as a synapse forming agent, and succinic acid as a morphology control agent; the mass percentage of the active component is 20-40% based on the mass of the carrier, the mass percentage of the cocatalyst is 1-5%, the mass ratio of cerium dioxide to yttrium oxide in the active component is 1:(0.2-0.5), and the mass ratio of praseodymium oxide to samarium oxide in the cocatalyst is 1:(0.5-2).

2. A process for the preparation of the catalyst of claim 1, characterized in that: The catalyst is prepared by the following method: (1) Preparation of an aluminum-titanium composite oxide carrier by a low-temperature hydrothermal method Titanium salt, aluminum salt, succinic acid and deionized water are uniformly mixed, and then placed in a hydrothermal reactor for hydrothermal reaction; after the reaction is completed, the aluminum-titanium composite oxide carrier is obtained by filtration, drying and calcination; (2) Preparation of a titanium dioxide carrier with a nanosynaptic structure by an alkali solution etching method The aluminum-titanium composite oxide carrier prepared in step (1) is placed in a sodium hydroxide solution, and heated in a water bath for reaction; after the reaction is completed, the titanium dioxide carrier with a nanosynaptic structure is obtained by filtration, washing, and drying in sequence; (3) Preparation of the catalyst by an impregnation loading method Cerium salt, yttrium salt, praseodymium salt, samarium salt and deionized water are uniformly mixed to obtain a composite precursor solution; then the titanium dioxide carrier with a nanosynaptic structure obtained in step (2) is placed in the composite precursor solution; the mixed solution is dried in an oven, and finally calcined in a muffle furnace to obtain the nanosynaptic structure low-temperature rare earth-based denitration catalyst.

3. The method of claim 2, wherein: In step (1), the titanium salt is tetrabutyl titanate or tetraethyl titanate, the aluminum salt is aluminum chloride or aluminum nitrate, and the mass ratio of the titanium salt, the aluminum salt and the succinic acid is 1:(0.5-1):(0.3-0.5).

4. The method of claim 2, wherein: In step (1), the temperature of the hydrothermal reaction is 110-130°C, the hydrothermal reaction time is 6-12h; the drying temperature is 80-100°C, the drying time is 6-12h; and the calcination temperature is 500-600°C, the calcination time is 2-4h.

5. The method of claim 2, wherein: In step (2), the mass ratio of sodium hydroxide to the aluminum-titanium composite oxide carrier is 1:(0.1-0.3).

6. The method of claim 2, wherein: In step (2), the water bath heating temperature is 50-70°C, the water bath heating time is 3-6h; the drying temperature is 80-100°C, and the drying time is 6-12h.

7. The method of claim 2, wherein: In step (3), the cerium salt is cerium nitrate hexahydrate or cerium chloride, the yttrium salt is yttrium nitrate hexahydrate or yttrium chloride, the praseodymium salt is praseodymium nitrate hexahydrate or praseodymium chloride, and the samarium salt is samarium nitrate hexahydrate or samarium chloride.

8. The method of claim 2, wherein: In step (3), the drying temperature is 80-100°C, the drying time is 3-6h; the calcination temperature is 500-600°C, and the calcination time is 3-6h.

9. The catalyst of claim 1 is used for low-temperature denitration in the steel sintering industry.

Images