A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag, its product and application

Abstract

The present invention discloses a method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag, its product and application, belonging to the field of solid waste resource utilization. The preparation process of the method of the present invention is simple, and the efficient resource utilization of red mud and electrolytic manganese slag can be realized through reasonable batching, hydrothermal reaction and pyrolytic carbonization processes, and no other waste liquid and secondary solid waste are generated during the preparation process. The prepared exhaust gas purification catalyst has excellent catalytic performance and can rapidly convert harmful gas of 1,2-dichlorobenzene.

Description

Technical Field

[0001] The present invention belongs to the field of resource utilization of solid waste, and particularly relates to a method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag, its product and application. Background Art

[0002] Harmful substances contained in the exhaust gas generated by various industrial production activities, such as sulfur dioxide, nitrogen oxides, volatile organic compounds, etc., will not only cause a decline in air quality, but also pose serious hazards to human health, such as causing respiratory diseases, cardiovascular diseases and even cancer, etc. Therefore, developing an efficient, economical and environmentally friendly exhaust gas purification catalyst has become the key to solving this environmental problem.

[0003] Among the numerous catalysts used for exhaust gas purification, although traditional catalysts have achieved certain application results, there are still many limitations. On the one hand, the cost of some traditional catalysts is high, mainly relying on precious metals or rare metal components, which makes them face economic bottlenecks in large-scale industrial applications and is difficult to popularize. On the other hand, during the actual operation of traditional catalysts, problems such as insufficient activity stability and easy poisoning and inactivation are faced, and frequent replacement or regeneration treatment is required, which further increases the operation cost and maintenance difficulty of exhaust gas purification.

[0004] At the same time, a large amount of industrial waste residue is generated during the industrial production process. Red mud, as the main waste of the aluminum industry, has an astonishing annual output. Its composition is complex, containing a large amount of metal oxides such as aluminum oxide and iron oxide, as well as impurities such as silicate. Long-term stacking occupies a large amount of land resources and there are potential environmental pollution risks, such as heavy metal leaching polluting soil and water bodies, etc. Electrolytic manganese slag is the main by-product during the production of electrolytic manganese, and also contains rich metal elements such as manganese and iron, as well as components such as sulfate. At present, it is mainly stacked, which not only causes waste of resources, but also may cause environmental problems such as acidic wastewater discharge.

[0005] However, most of the current research on the comprehensive utilization of red mud and electrolytic manganese slag focuses on traditional fields such as building materials and soil improvement, and fails to fully utilize their potential resource value. The present invention innovatively proposes a method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag. By scientifically treating and compounding and modifying the two waste residues, the metal oxides, silicate and other components in them are cleverly converted into highly efficient catalytic active components and carrier materials. This not only provides a catalyst with low cost, excellent catalytic performance and good stability for the exhaust gas purification field, realizes the high-value resource utilization of industrial waste residue, but also effectively solves the environmental pressure caused by the stacking of red mud and electrolytic manganese slag, and has significant environmental and economic benefits, and is expected to trigger a technological innovation based on waste utilization in the field of industrial exhaust gas purification. Summary of the Invention

[0006] Objective of the Invention: The objective of the present invention is to provide a method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag, its product, and its application.

[0007] Technical Solution: The method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag according to the present invention includes the following steps:

[0008] (1) Mix red mud and electrolytic manganese slag, stir evenly, and grind into powder to obtain red manganese slag material;

[0009] (2) Mix sulfuric acid waste liquid and phosphogypsum leachate, stir evenly, to obtain acid-loaded leachate;

[0010] (3) Mix the acid-loaded leachate and the red manganese slag material, stir evenly, to obtain a leached mixed slurry;

[0011] (4) Mix oily sludge and the leached mixed slurry, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction is completed, dry it, and finally obtain an oily red manganese precursor;

[0012] (5) Place the oily red manganese precursor in an atmosphere furnace for pyrolytic carbonization, and obtain an exhaust gas purification catalyst after pyrolysis is completed.

[0013] Further, the mass ratio of the red mud to the electrolytic manganese slag in step (1) is 20-60:100.

[0014] Further, the volume ratio of the sulfuric acid waste liquid to the phosphogypsum leachate in step (2) is 0.5-1.5:1.

[0015] Further, the liquid-solid ratio of the acid-loaded leachate to the red manganese slag material in step (3) is 1-3:1 mL / g, and the stirring time is 0.5-7.5 hours.

[0016] Further, the mass ratio of the oily sludge to the leached mixed slurry in step (4) is 50-100:100, the hydrothermal time is 0.5-5.5 hours, and the hydrothermal temperature is 120-360 °C.

[0017] Further, the pyrolysis temperature in step (5) is 350-950 °C, and the pyrolysis time is 0.5-4.5 hours.

[0018] The exhaust gas purification catalyst prepared by the method of the present invention as described above.

[0019] The application of the exhaust gas purification catalyst described in the present invention in treating polluted gases.

[0020] Further, the polluted gas is a gas containing 1,2-dichlorobenzene.

[0021] Reaction mechanism: Mix the acid-loaded leachate and red manganese residue. During the stirring process, components such as Al2O3, Fe2O3, CaO, and TiO2 in the red mud dissolve, releasing elements such as aluminum, iron, and titanium. Meanwhile, MnO2, Pb, MgO, Al2O3, Fe2O3, etc. in the electrolytic manganese residue dissolve, releasing elements such as manganese, lead, magnesium, and potassium, which then mix with the sulfate, ammonium, phosphate, fluoride, arsenic, etc. in the acid-loaded leachate and undergo chemical reactions. Mix the oily sludge and the leachate mixture slurry. During the stirring process, organic substances such as crude oil, aged crude oil, wax, and colloidal substances in the oily sludge wrap the undissolved and regenerated solid components in the leachate mixture slurry, and adsorb the dissolved metal ions and anionic substances such as sulfate, ammonium, phosphate, and fluoride in the leachate mixture slurry. During the hydrothermal process, the organic substances in the oily sludge undergo volatilization and cracking processes. Low-boiling light hydrocarbon substances and a small amount of aromatic hydrocarbons are released, and the gum and asphaltene substances dissolve and hydrolyze into small-molecule organic compound complexes, thus realizing the three-phase separation of oil, water, and mud. The small-molecule organic compound complexes will undergo complexation reactions with titanium, manganese, iron, lead, and other metal ions to form stable states. At the same time, some of the metal ions adsorbed in the oily sludge enter the aqueous phase and react with anions such as hydroxide, phosphate, and ammonium in the water to form mixed precipitates. The sulfides contained in the oily sludge decompose to generate hydrogen sulfide gas and metal sulfide precipitates. The hydrogen sulfide gas further combines with the hydrolyzed organic matter products in the oily sludge, thus realizing the mercaptanization of the oily sludge. Place the oil-red manganese precursor material into an atmosphere furnace for pyrolysis carbonization. The oil-phase substances and other organic substances in the oil-red manganese precursor material undergo pyrolysis. The carbon-carbon bonds, carbon-oxygen bonds, and carbon-hydrogen bonds in the organic substances break, generating carbon-based materials and releasing a reducing atmosphere. The complexed and adsorbed metal ions undergo reduction reactions with the reducing atmosphere on the carbon surface to generate carbon-supported composite metal-based catalytic materials with different valence states and different binding phases.

[0022] Beneficial effects: Compared with the prior art, the present invention has the following remarkable advantages: The preparation process of the method of the present invention is simple. The efficient resource utilization of red mud and electrolytic manganese residue can be realized through reasonable batching, hydrothermal reaction, and pyrolysis carbonization processes, and no other waste liquids and secondary solid wastes are generated during the preparation process. The prepared waste gas purification catalyst has excellent catalytic performance and can quickly convert harmful gases such as 1,2-dichlorobenzene. Description of the drawings

[0023] Figure 1 It is a flow chart of the treatment method of the present invention. Detailed implementation manners

[0024] The technical solutions of the present invention will be further described below in conjunction with the drawings.

[0025] Red mud: provided by Shandong Zibo Zhengheng Aluminum Co., Ltd., the main detected components include: 38.52% Fe2O3, 27.83% Al2O3, 12.49% SiO2, 11.36% Na2O, 5.61% TiO2, 0.57% CaO, 0.34% SO3 and other components (inevitable impurities and loss on ignition);

[0026] Electrolytic manganese residue: The electrolytic manganese residue is taken from Guizhou Nengkuang Manganese Industry Group Co., Ltd., mainly including 23.52% SO3, 13.17% SiO2, 15.21% CaO, 13.09% Fe2O3, 6.82% Al2O3, 10.21% MnO, 2.96% K2O, 1.55% MgO, 0.86% TiO2 and other components (inevitable impurities and loss on ignition);

[0027] Phosphogypsum leachate: The phosphogypsum stack leachate is obtained by sampling from the on-site collection pool of the phosphogypsum stack in Xifeng County, Guizhou. The pH is 2.23, the total phosphorus is 816 mg / L, the sulfate ion concentration is 2146 mg / L, the calcium ion concentration is 439.51 mg / L, the magnesium ion concentration is 564.89 mg / g, and the fluoride concentration is 91.37 mg / g;

[0028] Oil sludge: The oil sludge is taken from the refinery of Shaanxi Yanchang Petroleum, containing 34.51% extraction oil, 21.73% heavy oil, 27.44% slag and 16.32% water.

[0029] Sulfuric acid waste liquid: The sulfuric acid waste liquid comes from Anhui Jinlan Environmental Protection Technology Co., Ltd., containing 12.75% sulfuric acid and 16.32 mg / L ferrous ion.

[0030] Effect of the mass ratio of red mud and electrolytic manganese residue in Example 1 on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0031] Mix red mud and electrolytic manganese slag according to the mass ratios of 12.5:100, 15:100, 17.5:100, 20:100, 40:100, 60:100, 65:100, 70:100, and 75:100, stir evenly, grind into powder, and obtain red manganese slag material. Mix sulfuric acid waste liquid and phosphogypsum leachate according to the volume ratio of 0.5:1, stir evenly, and obtain acid-loaded leachate. Mix the acid-loaded leachate and red manganese slag material according to the liquid-solid ratio of 1:1 mL / g, stir for 0.5 hours, and obtain leaching mixed slurry. Mix oil sludge and leaching mixed slurry according to the mass ratio of 50:100, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain oil red manganese precursor material, where the hydrothermal time is 0.5 hours and the hydrothermal temperature is 120 °C. Place the oil red manganese precursor material in an atmosphere furnace for pyrolysis carbonization, and obtain waste gas purification catalyst after pyrolysis, where the pyrolysis temperature is 350 °C and the pyrolysis time is 0.5 hours.

[0032] Performance test of 1,2-dichlorobenzene waste gas removal catalyst: Turn on the steam generator to generate 1,2-dichlorobenzene gas, and then simultaneously introduce 1,2-dichlorobenzene gas and balance gas (20% oxygen + 80% nitrogen) into the mixing gas box. After mixing, the concentration of 1,2-dichlorobenzene gas in the mixing gas box is 200 ppmv, and then lead the 1,2-dichlorobenzene gas to a fixed-bed reactor, and set the gas flow rate to 40 mL / min. Fill 200 mg of 1,2-dichlorobenzene waste gas removal catalyst in the middle of the fixed-bed reactor, and control the reactor temperature at 350 °C. The 1,2-dichlorobenzene gas enters from the inlet of the fixed-bed reactor, reacts in the catalyst filling area of the fixed-bed reactor, and is discharged from the outlet after 30 minutes for on-line detection. The concentration of 1,2-dichlorobenzene gas is detected by a GC1100-gas chromatograph (equipped with a flame ionization detector). The removal rate of 1,2-dichlorobenzene gas ( ) is calculated according to formula (1), where is the concentration of 1,2-dichlorobenzene gas at the inlet, is the concentration of 1,2-dichlorobenzene gas at the outlet, and the test results are shown in Table 1.

[0033] (1)

[0034] The test results of this example are shown in Table 1.

[0035] Table 1 Influence of the mass ratio of red mud and electrolytic manganese slag on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0036]

[0037] As can be seen from Table 1, when the mass ratio of red mud to electrolytic manganese slag is less than 20:100 (as in Table 1, when the mass ratio of red mud to electrolytic manganese slag = 17.5:100, 15:100, 12.5:100 and lower ratios not listed in Table 1), less red mud is added and the reaction between red mud and electrolytic manganese slag is insufficient, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst as the mass ratio of red mud to electrolytic manganese slag decreases. When the mass ratio of red mud to electrolytic manganese slag is equal to 20 - 60:100 (as in Table 1, when the mass ratio of red mud to electrolytic manganese slag = 20:100, 40:100, 60:100), the mixed acid-loaded leachate and red manganese slag material are stirred. During the stirring process, components such as Al2O3, Fe2O3, CaO, and TiO2 in the red mud dissolve, releasing elements such as aluminum, iron, and titanium, while MnO2, Pb, MgO, Al2O3, and Fe2O3 in the electrolytic manganese slag dissolve, releasing elements such as manganese, lead, magnesium, and potassium, and they mix with sulfate, ammonium, phosphate, fluorine, arsenic, etc. in the mixed acid-loaded leachate and undergo chemical reactions. Finally, the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst is higher than 89%. When the mass ratio of red mud to electrolytic manganese slag is greater than 60:100 (as in Table 1, when the mass ratio of red mud to electrolytic manganese slag = 65:100, 70:100, 75:100 and higher ratios not listed in Table 1), excessive red mud is added and the reaction between red mud and electrolytic manganese slag is unbalanced, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst as the mass ratio of red mud to electrolytic manganese slag further increases. Generally speaking, considering the benefits and costs, when the mass ratio of red mud to electrolytic manganese slag is equal to 20 - 60:100, it is most beneficial to improve the catalytic performance of the prepared catalytic material.

[0038] Effect of the liquid-solid ratio of the acid-loaded leachate and red manganese slag material on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas in Example 2

[0039] Mix red mud and electrolytic manganese slag according to a mass ratio of 60:100, stir evenly, grind into powder to obtain red manganese slag material. Mix sulfuric acid waste liquid and phosphogypsum leachate according to a volume ratio of 1:1, stir evenly to obtain acid-loaded leachate. Mix the acid-loaded leachate and red manganese slag material according to a liquid-solid ratio of 0.25:1 mL / g, 0.5:1 mL / g, 0.75:1 mL / g, 1:1 mL / g, 2:1 mL / g, 3:1 mL / g, 3.5:1 mL / g, 4:1 mL / g, 4.5:1 mL / g, stir for 4 hours to obtain a leached mixed slurry. Mix oil sludge and the leached mixed slurry according to a mass ratio of 75:100, stir evenly, carry out hydrothermal reaction. After the hydrothermal reaction, the obtained slurry is granulated and dried to finally obtain an oil-red manganese precursor material, where the hydrothermal time is 3 hours and the hydrothermal temperature is 240 °C. Place the oil-red manganese precursor material in an atmosphere furnace for pyrolytic carbonization, and after the pyrolysis, an exhaust gas purification catalyst is obtained, where the pyrolysis temperature is 650 °C and the pyrolysis time is 2.5 hours.

[0040] The performance test of the catalyst for removing 1,2-dichlorobenzene waste gas was the same as that in Example 1. The test results of this example are shown in Table 2.

[0041] Table 2 Influence of the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0042]

[0043] As can be seen from Table 2, when the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry is less than 1:1 mL / g (as in Table 2, when the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry = 0.75:1 mL / g, 0.5:1 mL / g, 0.25:1 mL / g and lower ratios not listed in Table 2), less acid-loaded leachate is added, and the reaction between the acid-loaded leachate and the pyrolusite residue slurry is insufficient, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst as the liquid-solid ratio of the acid-loaded leachate and the pyrolusite residue slurry decreases. When the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry is equal to 1 - 3:1 mL / g (as in Table 2, when the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry = 1:1 mL / g, 2:1 mL / g, 3:1 mL / g), when the mixed acid-loaded leachate and pyrolusite residue slurry are stirred, components such as Al2O3, Fe2O3, CaO, and TiO2 in the red mud dissolve, releasing elements such as aluminum, iron, and titanium, while MnO2, Pb, MgO, Al2O3, and Fe2O3 in the electrolytic manganese residue dissolve, releasing elements such as manganese, lead, magnesium, and potassium, and reacting with the sulfate, ammonium, phosphate, fluorine, arsenic, etc. in the mixed acid-loaded leachate and undergoing chemical reactions. Finally, the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst is higher than 92%. When the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry is greater than 3:1 mL / g (as in Table 2, when the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry = 3.5:1 mL / g, 4:1 mL / g, 4.5:1 mL / g and higher ratios not listed in Table 2), the acid-loaded leachate is added in excess, and the reaction between the acid-loaded leachate and the pyrolusite residue slurry is unbalanced, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas by the prepared catalyst as the liquid-solid ratio of the acid-loaded leachate and the pyrolusite residue slurry further increases. Generally speaking, considering the benefits and costs, when the liquid-solid ratio of acid-loaded leachate and pyrolusite residue slurry is equal to 1 - 3:1 mL / g, it is most beneficial to improve the catalytic performance of the prepared catalytic material.

[0044] Example 3 Influence of the mass ratio of oily sludge and leachate mixed slurry on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0045] Mix red mud and electrolytic manganese slag in a mass ratio of 60:100, stir evenly, grind into powder to obtain red manganese slag material. Mix sulfuric acid waste liquid and phosphogypsum leachate in a volume ratio of 1.5:1, stir evenly to obtain acid-loaded leachate. Mix the acid-loaded leachate and red manganese slag material in a liquid-solid ratio of 3:1 mL / g, stir for 7.5 hours to obtain a leaching mixed slurry. Mix oil sludge and the leaching mixed slurry in mass ratios of 35:100, 40:100, 45:100, 50:100, 75:100, 100:100, 125:100, 150:100, 175:100, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain an oil-red manganese precursor material, where the hydrothermal time is 5.5 hours and the hydrothermal temperature is 360 °C. Place the oil-red manganese precursor material in an atmosphere furnace for pyrolytic carbonization, and obtain an exhaust gas purification catalyst after pyrolysis, where the pyrolysis temperature is 950 °C and the pyrolysis time is 4.5 hours.

[0046] The performance test of the catalyst for removing 1,2-dichlorobenzene waste gas is the same as that in Example 1, and the test results of this example are shown in Table 3.

[0047] Table 3 Influence of the mass ratio of oil sludge and leaching mixed slurry on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0048]

[0049] As can be seen from Table 3, when the mass ratio of oily sludge to leachate slurry is less than 50:100 (as in Table 3, when the mass ratio of oily sludge to leachate slurry = 45:100, 40:100, 35:100 and lower ratios not listed in Table 3), less oily sludge is added, and the reaction between the oily sludge and the leachate slurry is insufficient during the hydrothermal reaction process and the pyrolysis carbonization process, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas of the prepared catalyst with the decrease of the mass ratio of oily sludge to leachate slurry. When the mass ratio of oily sludge to leachate slurry is equal to 50 - 100:100 (as in Table 3, when the mass ratio of oily sludge to leachate slurry = 50:100, 75:100, 100:100), the mixed oily sludge and leachate slurry, during the stirring process, organic substances such as crude oil, aged crude oil, wax, and colloidal substances in the oily sludge wrap the undissolved and regenerated solid components in the leachate slurry, and adsorb the dissolved metal ions and anionic substances such as sulfate, ammonium, phosphate, and fluoride in the leachate slurry. During the hydrothermal process, the organic substances in the oily sludge undergo volatilization and cracking processes, low-boiling light hydrocarbon substances and a small amount of aromatic hydrocarbons are released, and the gum and asphaltene substances dissolve and hydrolyze into small-molecule organic compound complexes, thus realizing the three-phase separation of oil, water, and mud. The small-molecule organic compound complexes will undergo complexation reactions with titanium, manganese, iron, lead, and other metal ions to form stable states. At the same time, some of the metal ions adsorbed in the oily sludge enter the aqueous phase and react with anions such as hydroxide, phosphate, and ammonium in the water to form mixed precipitates. The sulfides contained in the oily sludge decompose to generate hydrogen sulfide gas and metal sulfide precipitates. The hydrogen sulfide gas further combines with the hydrolyzed organic matter products in the oily sludge, thus realizing the mercaptanization of the oily sludge. The oil-manganomanganic oxide precursor is placed in an atmosphere furnace for pyrolysis carbonization. The oil-phase substances and other organic substances in the oil-manganomanganic oxide precursor undergo pyrolysis, and the carbon-carbon bonds, carbon-oxygen bonds, and carbon-hydrogen bonds in the organic substances are broken, generating carbon-based materials and releasing a reducing atmosphere. The complexed and adsorbed metal ions undergo reduction reactions with the reducing atmosphere on the carbon-based surface to generate carbon-supported composite metal-based catalytic materials with different valence states and different binding phases. Finally, the removal rate of 1,2-dichlorobenzene gas of the prepared catalyst is higher than 96%. When the mass ratio of oily sludge to leachate slurry is greater than 100:100 (as in Table 3, when the mass ratio of oily sludge to leachate slurry = 125:100, 150:100, 175:100 and higher ratios not listed in Table 3), excessive oily sludge is added, and the reaction between the oily sludge and the leachate slurry is unbalanced during the hydrothermal and pyrolysis processes, resulting in a significant decrease in the removal rate of 1,2-dichlorobenzene gas of the prepared catalyst with the further increase of the mass ratio of oily sludge to leachate slurry. Generally speaking, considering the benefits and costs, when the mass ratio of oily sludge to leachate slurry is equal to 50 - 100:100, it is most beneficial to improve the catalytic performance of the prepared catalytic material.

[0050] Comparative Example Influence of Different Comparative Processes on the Performance of the Prepared Catalyst for Removing 1,2-Dichlorobenzene Exhaust Gas

[0051] Process of the present invention: Mix red mud and electrolytic manganese slag in a mass ratio of 40:100, stir evenly, grind into powder to obtain red manganese slag material. Mix sulfuric acid waste liquid and phosphogypsum leachate in a volume ratio of 1.5:1, stir evenly to obtain acid-loaded leachate. Mix the acid-loaded leachate and red manganese slag material in a liquid-solid ratio of 3:1 mL / g, stir for 7.5 hours to obtain a leached mixed slurry. Mix oily sludge and the leached mixed slurry in a mass ratio of 100:100, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain an oily red manganese precursor material, where the hydrothermal time is 5.5 hours and the hydrothermal temperature is 360 °C. Place the oily red manganese precursor material in an atmosphere furnace for pyrolysis carbonization, and obtain an exhaust gas purification catalyst after pyrolysis, where the pyrolysis temperature is 650 °C and the pyrolysis time is 2.5 hours.

[0052] Comparative process 1: Mix red mud and electrolytic manganese slag in a mass ratio of 40:100, stir evenly, grind into powder to obtain red manganese slag material. Mix sulfuric acid waste liquid and red manganese slag material in a liquid-solid ratio of 3:1 mL / g, stir for 7.5 hours to obtain a leached mixed slurry. Mix oily sludge and the leached mixed slurry in a mass ratio of 100:100, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain an oily red manganese precursor material, where the hydrothermal time is 5.5 hours and the hydrothermal temperature is 360 °C. Place the oily red manganese precursor material in an atmosphere furnace for pyrolysis carbonization, and obtain an exhaust gas purification catalyst after pyrolysis, where the pyrolysis temperature is 650 °C and the pyrolysis time is 2.5 hours.

[0053] Comparative process 2: Mix red mud and electrolytic manganese slag in a mass ratio of 40:100, stir evenly, grind into powder to obtain red manganese slag material. Mix sulfuric acid waste liquid and phosphogypsum leachate in a volume ratio of 1.5:1, stir evenly to obtain acid-loaded leachate. Mix the acid-loaded leachate and red manganese slag material in a liquid-solid ratio of 3:1 mL / g, stir for 7.5 hours, then carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain a red manganese precursor material, where the hydrothermal time is 5.5 hours and the hydrothermal temperature is 360 °C. Place the red manganese precursor material in an atmosphere furnace for pyrolysis carbonization, and obtain an exhaust gas purification catalyst after pyrolysis, where the pyrolysis temperature is 650 °C and the pyrolysis time is 2.5 hours.

[0054] The performance test of the 1,2-dichlorobenzene waste gas removal catalyst is the same as that in Example 1, and the test results of this example are shown in Table 4.

[0055] Table 4 Influence of different comparative processes on the performance of the prepared catalyst for removing 1,2-dichlorobenzene waste gas

[0056]

[0057] As can be seen from Table 4, the removal rate of 1,2-dichlorobenzene gas by the catalyst prepared by the process of the present invention is significantly higher than that of Comparative Process 1 and Comparative Process 2.

Claims

1. A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag, characterized in that, It includes the following steps: (1) Mix red mud and electrolytic manganese slag, stir evenly, and grind into powder to obtain red manganese slag material; The mass ratio of the red mud to the electrolytic manganese slag is 20 - 60:100; (2) Mix sulfuric acid waste liquid and phosphogypsum leachate, stir evenly to obtain acid-loaded leachate; (3) Mix the acid-loaded leachate and the red manganese slag material, stir evenly to obtain a leaching mixed slurry; The liquid-solid ratio of the acid-loaded leachate to the red manganese slag material is 1 - 3:1 mL / g; (4) Mix oily sludge and the leaching mixed slurry, stir evenly, carry out hydrothermal reaction, granulate the slurry after hydrothermal reaction, dry it, and finally obtain an oily red manganese precursor; The mass ratio of the oily sludge to the leaching mixed slurry is 50 - 100:100; (5) Place the oily red manganese precursor in an atmosphere furnace for pyrolytic carbonization, and obtain an exhaust gas purification catalyst after pyrolysis.

2. A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag according to claim 1, characterized in that, In step (2), the volume ratio of the sulfuric acid waste liquid to the phosphogypsum leachate is 0.5 - 1.5:

1.

3. A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag according to claim 1, characterized in that, In step (3), the stirring time is 0.5 - 7.5 hours.

4. A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag according to claim 1, characterized in that, In step (4), the mass ratio of the oily sludge to the leaching mixed slurry is 50 - 100:100, the hydrothermal time is 0.5 - 5.5 hours, and the hydrothermal temperature is 120 - 360 °C.

5. A method for preparing an exhaust gas purification catalyst using red mud and electrolytic manganese slag according to claim 1, characterized in that, In step (5), the pyrolysis temperature is 350 - 950 °C, and the pyrolysis time is 0.5 - 4.5 hours.

6. An exhaust gas purification catalyst prepared by the method according to any one of claims 1 - 5.

7. Use of the waste gas purification catalyst according to claim 6 in treating polluted gas, characterized in that, The polluted gas is a gas containing 1,2-dichlorobenzene.

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