Wear-resistant attapulgite honeycomb material with self-cleaning function as well as preparation method and application of wear-resistant attapulgite honeycomb material

Abstract

The invention discloses a wear-resistant attapulgite honeycomb material with a self-cleaning function as well as a preparation method and application thereof, and belongs to the technical field of atmospheric pollution control and environment-friendly materials. The problems that in the prior art, a titanium-based denitration carrier is high in abrasion rate and serious in dust deposition in high-dust flue gas are solved. The preparation method comprises the following steps: firstly, adding attapulgite powder into an acid solution, continuously stirring, filtering, cleaning and drying to obtain pretreated attapulgite powder; dissolving a metal salt and a modifier in an ethanol solution, uniformly mixing, carrying out ball milling on the obtained mixed solution and the pretreated attapulgite powder, and carrying out heat preservation to obtain secondarily modified attapulgite powder; and finally, pugging a structure aid, a forming aid, an extrusion aid, a binder and the secondarily modified attapulgite powder, carrying out extrusion forming on the obtained pug, drying, and calcining to obtain the attapulgite honeycomb material. The attapulgite honeycomb material has the advantages of low cost, high mechanical strength and dust suppression performance, and can be used as a carrier of a denitration catalyst.

Description

Technical Field

[0001] The present invention belongs to the technical fields of air pollution control and environmental protection materials. Specifically, it relates to a wear-resistant attapulgite honeycomb material with self-cleaning function, its preparation method and application, and particularly relates to the application of the wear-resistant attapulgite honeycomb material with self-cleaning function as a carrier of a denitration catalyst. Background Art

[0002] Currently, most of the denitration honeycomb catalysts commonly used in industry are based on titanium dioxide (accounting for more than 85%), and are extruded or coated for the treatment of nitrogen oxides. However, when titanium-based catalysts are applied in high-dust scenarios, problems such as easy wear or ash accumulation are extremely likely to occur, severely restricting the service life and catalytic performance of the catalysts. Moreover, titanium dioxide is expensive, and the production has large pollution, a long process, and high energy consumption. Attapulgite, as an inexpensive and easily available natural green ore soil, has advantages such as a special nano-porous structure, a large specific surface area, strong ion exchange ability, and high mechanical strength after sintering, and can be used as a potential substitute for low-cost catalyst carriers. However, natural attapulgite has deficiencies such as many impurities, large grade fluctuations, few acidic sites and functional groups. Therefore, how to modify and regulate attapulgite to make it have both high mechanical strength and dust-repellent characteristics is a key technical problem to be solved.

[0003] Patent CN115888634B discloses a high-strength water-resistant adsorbent and its preparation method. This method uses two attapulgites with different properties as the main raw materials, supplemented by glycerol, a pore-expanding agent and an organic binder, kneaded, pugged, formed, and then dried and calcined by microwave for shaping; finally, the honeycomb material is impregnated in a solution containing a hydrophobic modifier and vacuum dried to finally prepare a high-strength water-resistant attapulgite honeycomb adsorbent. Although this technology can improve the mechanical strength and hydrophobic energy absorption of the honeycomb material to a certain extent, there are still problems such as insufficient mechanical strength and lack of investigation on the dust adsorption performance. Summary of the Invention

[0004] In order to solve the disadvantages of high wear rate and serious ash accumulation of titanium-based denitration carriers in the prior art, the present invention provides a wear-resistant attapulgite honeycomb material with self-cleaning function, its preparation method and application. The attapulgite honeycomb material has low cost, high mechanical strength and dust suppression performance, and can be used as a carrier of a denitration catalyst.

[0005] The technical solutions adopted by the present invention to solve the above technical problems are as follows.

[0006] In the first aspect, the present invention provides a preparation method of a wear-resistant attapulgite honeycomb material with self-cleaning function, including the following steps: Step 1: Add attapulgite powder into an acidic solution. After continuous stirring, filter and wash until the pH value of the filtrate is 6 - 7, then dry to obtain pretreated attapulgite powder; The acidic solution is a mixed solution of a monobasic acid solution, a polybasic acid solution and an ammonium salt solution; Step 2: Dissolve a metal salt and a modifier in an ethanol solution, mix evenly to obtain a mixed solution. Under the protection of an inert atmosphere, ball-mill the pretreated attapulgite powder and the mixed solution, and keep warm to obtain the attapulgite powder after secondary modification; Step 3: Knead a structure assistant, a forming assistant, an extrusion aid, a binder and the attapulgite powder after secondary modification, extrude and form the obtained mud, dry and calcine to obtain a wear-resistant attapulgite honeycomb material with self-cleaning function.

[0007] Preferably, in Step 1, the mass ratio of the attapulgite powder to the acidic solution is 0.2 - 0.5:1.

[0008] Preferably, in Step 1, the concentration of the monobasic acid solution is 1.0 - 3.0 mol / L, the concentration of the polybasic acid solution is 0.5 - 2.0 mol / L, the concentration of the ammonium salt solution is 0.1 - 2.0 mol / L, and the mass ratio of the monobasic acid solution, the polybasic acid solution and the ammonium salt solution is 0.1 - 0.5:0.2 - 0.6:0.1 - 0.4.

[0009] Preferably, in Step 1, the monobasic acid is hydrochloric acid, nitric acid, hydrofluoric acid or acetic acid.

[0010] Preferably, in Step 1, the polybasic acid is sulfuric acid, tartaric acid, phosphoric acid or malonic acid.

[0011] Preferably, in Step 1, the ammonium salt is ammonium carbonate, ammonium sulfate, ammonium chloride or ammonium fluoride.

[0012] Preferably, in Step 1, the temperature of the continuous stirring is 20°C - 60°C, and the time of the continuous stirring is 2 - 4 hours.

[0013] Preferably, in Step 2, the metal salt is ferric nitrate, zirconium nitrate, chromium nitrate or cerium nitrate, and the mass ratio of the metal salt (calculated by the mass of the oxide) to the pretreated attapulgite powder is 0.05 - 0.1:1.

[0014] Preferably, in Step 2, the modifier is methylphenyl silicone resin, dodecyl phosphate or aluminate coupling agent (DL-411), and the mass ratio of the modifier to the pretreated attapulgite powder is 0.01 - 0.05:1.

[0015] Preferably, in Step 2, the mass concentration of the ethanol solution is 1% - 5%, and the mass ratio of the ethanol solution to the pretreated attapulgite powder is 0.5 - 1:1.

[0016] Preferably, in step two, the way of mixing evenly is ultrasonic, and the ultrasonic time is 20 to 120 minutes.

[0017] Preferably, in step two, the inert atmosphere is nitrogen.

[0018] Preferably, in step two, the ball milling time is 4 to 8 hours, the heat preservation temperature is 80 to 100 °C, the heat preservation time is 2 to 6 hours, and the temperature is raised to the heat preservation temperature at a heating rate of 5 °C / minute.

[0019] Preferably, in step three, the structure assistant is one or more of silicon carbide nanofibers, glass fibers, and aluminum silicate ceramic fibers, and the mass ratio of the structure assistant to the attapulgite powder after secondary modification is 0.05 to 0.1:1.

[0020] Preferably, in step three, the molding assistant is one or more of lactic acid, polyacrylic acid, and polysorbate, and the mass ratio of the structure assistant to the attapulgite powder after secondary modification is 0.01 to 0.05:1.

[0021] Preferably, in step three, the extrusion aid is one or more of ethylene glycol, glycerol, and triphosphate, and the mass ratio of the extrusion aid to the attapulgite powder after secondary modification is 0.01 to 0.05:1.

[0022] Preferably, in step three, the binder is one or more of carboxymethyl cellulose, polyacrylamide, and polyethylene oxide, and the mass ratio of the binder to the attapulgite powder after secondary modification is 0.05 to 0.2:1.

[0023] Preferably, in step three, the clay kneading is repeated 3 to 5 times.

[0024] Preferably, in step three, the drying temperature is 30 to 90 °C, and the drying time is 4 to 6 days.

[0025] Preferably, in step three, the calcination temperature is 500 to 600 °C, and the calcination time is 2 to 6 hours.

[0026] In the second aspect, the present invention provides a wear-resistant attapulgite honeycomb material with self-cleaning function prepared by the above preparation method.

[0027] In the third aspect, the present invention provides the application of the above wear-resistant attapulgite honeycomb material with self-cleaning function as a carrier of a denitration catalyst.

[0028] Compared with the prior art, the present invention has the following beneficial effects: Preparation method of wear-resistant attapulgite honeycomb material with self-cleaning function of the present invention. A mixed solution of a monobasic acid solution, a polybasic acid solution and an ammonium salt solution is used for pre-treating attapulgite, achieving the functions of impurity removal, pore dredging and pore expansion for attapulgite. On the one hand, the mixed solution can dissolve and complex and remove impurities such as calcite, dolomite, quartz and partial organic matters in attapulgite, greatly improving the grade of attapulgite. On the other hand, the mixed solution can dredge and etch the pore structure of attapulgite, increasing the specific surface area and pore volume and pore diameter.

[0029] Preparation method of wear-resistant attapulgite honeycomb material with self-cleaning function of the present invention. By introducing metal salts and modifiers, partial cations of attapulgite can be ion-exchanged, improving the redox performance of attapulgite and reducing the dust adhesion ability, while increasing the mechanical strength of molding.

[0030] Preparation method of wear-resistant attapulgite honeycomb material with self-cleaning function of the present invention. Various additives added during the molding process contribute to the rapid extrusion molding of the honeycomb, with a short molding cycle and a high qualified rate of finished products; it can further increase the mechanical strength of the attapulgite after molding and has a small influence on the specific surface area, and can be used as a carrier for denitration catalysts.

[0031] The attapulgite honeycomb material prepared by the present invention has excellent dust suppression performance and high mechanical strength, and low cost, and can be used as a carrier for denitration catalysts. Detailed implementation mode

[0032] To facilitate the understanding of the present invention, various exemplary implementation modes of the present invention are now described in detail. This detailed description should not be regarded as a specific limitation of the present invention, but should be understood as a more detailed description of certain aspects, characteristics and implementation modes of the present invention.

[0033] Preparation method of wear-resistant attapulgite honeycomb material with self-cleaning function of the present invention includes the following steps: Step 1: Add attapulgite powder to an acidic solution, continuously stir, then filter, wash until the pH value of the filtrate is 6 - 7, and dry to obtain pre-treated attapulgite powder; Step 2: Dissolve metal salts and modifiers in an ethanol solution, mix evenly to obtain a mixed solution. Under the protection of an inert atmosphere, ball-mill the pre-treated attapulgite powder and the mixed solution, and keep warm to obtain the attapulgite powder after secondary modification; Step 3: Knead the structural additive, molding additive, extrusion aid, binder and the attapulgite powder after secondary modification to form a mud, extrude and mold the obtained mud, dry and calcine to obtain a wear-resistant attapulgite honeycomb material with self-cleaning function.

[0034] In step one of the present invention, the acidic solution is a mixed solution of a monobasic acid solution, a polybasic acid solution and an ammonium salt solution, and the acidic solution functions to remove impurities, make pores and expand pores of attapulgite. Preferably, the monobasic acid is hydrochloric acid, nitric acid, hydrofluoric acid or acetic acid, and the concentration of the monobasic acid solution is 1.0 - 3.0 mol / L. For example, in some embodiments, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L, 2.5 mol / L, 3.0 mol / L are adopted, but not limited thereto. Preferably, the polybasic acid is sulfuric acid, tartaric acid, phosphoric acid or malonic acid, and the concentration of the polybasic acid solution is 0.5 - 2.0 mol / L. For example, in some embodiments, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L are adopted, but not limited thereto. Preferably, the ammonium salt is ammonium carbonate, ammonium sulfate, ammonium chloride or ammonium fluoride, and the concentration of the ammonium salt solution is 0.1 - 2.0 mol / L. For example, in some embodiments, 0.1 mol / L, 0.5 mol / L, 1.0 mol / L, 1.5 mol / L, 2.0 mol / L are adopted, but not limited thereto. Preferably, the mass ratio of the monobasic acid solution, the polybasic acid solution and the ammonium salt solution is 0.1 - 0.5:0.2 - 0.6:0.1 - 0.4. For example, in some embodiments, 0.5:0.4:0.1, 0.4:0.3:0.3, 0.3:0.5:0.1, 0.1:0.5:0.4 are adopted, but not limited thereto.

[0035] In step one of the present invention, preferably, the mass ratio of the attapulgite powder to the acidic solution is 0.2 - 0.5:1. For example, in some embodiments, 0.2:1, 0.3:1, 0.4:1, 0.5:1 are adopted, but not limited thereto.

[0036] In step one of the present invention, preferably, the temperature of continuous stirring is 20°C - 60°C, and the time of continuous stirring is 2 - 4 hours. Usually, water washing is adopted.

[0037] In step two of the present invention, preferably, the metal salt is a metal nitrate, such as iron nitrate, zirconium nitrate, chromium nitrate or cerium nitrate, and the mass ratio of the metal salt (calculated based on the mass of the metal oxide) to the pretreated attapulgite powder is 0.05 - 0.1:1. For example, in some embodiments, 0.05:1, 0.06:1, 0.07:1, 0.08:1, 0.09:1, 0.1:1 are adopted, but not limited thereto.

[0038] In step two of the present invention, preferably, the modifier is methyl phenyl silicone resin, dodecyl phosphate or aluminate coupling agent (DL - 411), and the mass ratio of the modifier to the pretreated attapulgite powder is 0.01 - 0.05:1. For example, in some embodiments, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1 are adopted, but not limited thereto.

[0039] In step two of the present invention, preferably, the mass concentration of the ethanol solution is 1% - 5%. For example, in some embodiments, 1%, 2%, 3%, 4%, 5% are adopted, but it is not limited thereto. The mass ratio of the ethanol solution to the pretreated attapulgite powder is 0.5 - 1:1. For example, in some embodiments, 0.5:1, 0.6:1, 0.7:1, 0.8:1, 0.9:1, 1:1 are adopted, but it is not limited thereto.

[0040] In step two of the present invention, preferably, the way of mixing evenly is ultrasonic, and the ultrasonic time is 20 - 120 minutes.

[0041] In step two of the present invention, preferably, the inert atmosphere is nitrogen.

[0042] In step two of the present invention, preferably, the ball milling time is 4 - 8 hours, the heat preservation temperature is 80 - 100 °C, the heat preservation time is 2 - 6 hours, and the temperature is raised to the heat preservation temperature at a heating rate of 5 °C / minute.

[0043] In step three of the present invention, preferably, the structure assistant is one or several of silicon carbide nanofibers, glass fibers, and aluminum silicate ceramic fibers, and the mass ratio of the structure assistant to the attapulgite powder after secondary modification is 0.05 - 0.1:1.

[0044] In step three of the present invention, preferably, the forming assistant is one or several of lactic acid, polyacrylic acid, and polysorbate, and the mass ratio of the structure assistant to the attapulgite powder after secondary modification is 0.01 - 0.05:1. For example, in some embodiments, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1 are adopted, but it is not limited thereto.

[0045] In step three of the present invention, preferably, the extrusion aid is one or several of ethylene glycol, glycerol, and triphosphate, and the mass ratio of the extrusion aid to the attapulgite powder after secondary modification is 0.01 - 0.05:1. For example, in some embodiments, 0.01:1, 0.02:1, 0.03:1, 0.04:1, 0.05:1 are adopted, but it is not limited thereto.

[0046] In step three of the present invention, preferably, the binder is one or several of carboxymethyl cellulose, polyacrylamide, and polyethylene oxide, and the mass ratio of the binder to the attapulgite powder after secondary modification is 0.05 - 0.2:1. For example, in some embodiments, 0.05:1, 0.1:1, 0.15:1, 0.2:1 are adopted, but it is not limited thereto.

[0047] In step three of the present invention, preferably, the clay kneading is repeated 3 - 5 times.

[0048] In step three of the present invention, preferably, the drying temperature is 30 - 90 °C, and the drying time is 4 - 6 days.

[0049] In step three of the present invention, the preferred calcination temperature is 500-600 °C and the calcination time is 2-6 hours.

[0050] The wear-resistant attapulgite honeycomb material with self-cleaning function prepared by the preparation method of the present invention can be used as a carrier for denitration catalysts. There are no special restrictions on the specific application method, and the application method of denitration catalyst carriers in the prior art can be referred to.

[0051] In order to enable those skilled in the art to better understand the technical solution of the present invention, the present invention will be further described in detail below in conjunction with examples and comparative examples.

[0052] In the following examples and comparative examples, various processes and methods not described in detail are conventional methods well known in the art. The materials, reagents, devices, instruments, equipment, etc. used in the following examples and comparative examples can be obtained from commercial channels without special instructions. It should be noted that the solvent of the solutions in the examples and comparative examples is water. For example, "hydrochloric acid solution" means "aqueous hydrochloric acid solution".

[0053] Example 1 Step 1: Stir 12.5 kg of 1.0 mol / L hydrochloric acid solution, 10 kg of 0.5 mol / L sulfuric acid solution and 2.5 kg of 0.1 mol / L ammonium carbonate solution evenly to obtain an acidic solution. Add 5 kg of attapulgite powder to the above acidic solution, continuously stir at 20 °C for 4 hours, then filter, wash until the pH value of the filtrate is 7, and dry to obtain pretreated attapulgite powder.

[0054] Step 2: Dissolve 0.2 kg of iron nitrate and 0.04 kg of methylphenyl silicone resin in 2 kg of 1% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 20 minutes; add 4 kg of the pretreated attapulgite powder obtained in step 1 and the above mixed solution to a planetary ball mill and ball mill for 4 hours under nitrogen protection. Heat the ball-milled powder to 80 °C at a rate of 5 °C / min under nitrogen protection and keep it warm for 6 hours to obtain the secondary modified attapulgite powder; Step 3: Add 0.2 kg of silicon carbide nanofibers, 0.04 kg of lactic acid, 0.04 kg of ethylene glycol, 0.2 kg of carboxymethyl cellulose and 4 kg of the secondary modified attapulgite powder obtained in step 2 to a vacuum kneader and knead repeatedly 3 times, then extrude the mud through a molding extruder, and dry the molded product at 40 °C for 6 days; calcine the dried honeycomb carrier at 500 °C for 6 hours to obtain the wear-resistant attapulgite honeycomb material with self-cleaning function.

[0055] Example 2 Step 1: Stir 6.4 kg of 1.5 mol / L nitric acid solution, 4.8 kg of 1 mol / L tartaric acid solution and 4.8 kg of 0.5 mol / L ammonium sulfate solution evenly to obtain an acidic solution. Add 5 kg of attapulgite powder to the above acidic solution, continuously stir at 30°C for 3 hours, then filter and wash until the pH value of the filtrate is 7, and dry to obtain the pretreated attapulgite powder.

[0056] Step 2: Dissolve 0.28 kg of zirconium nitrate and 0.08 kg of dodecyl phosphate in 2.8 kg of 3% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 30 minutes; add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution to a planetary ball mill and ball mill under nitrogen protection for 5 hours. Heat the ball-milled powder to 90°C at a rate of 5°C / min under nitrogen protection and keep it warm for 5 hours to obtain the secondary modified attapulgite powder; Step 3: Add 0.24 kg of glass fiber, 0.08 kg of polyacrylic acid, 0.12 kg of glycerol, 0.32 kg of polyacrylamide and 4 kg of the secondary modified attapulgite powder obtained in Step 2 to a vacuum kneader and knead 4 times repeatedly, then extrude the clay material through an extrusion molding machine, and dry the molded product at 50°C for 5 days; calcine the dried honeycomb carrier at 550°C for 5 hours to obtain the wear-resistant attapulgite honeycomb material with self-cleaning function.

[0057] Example 3 Step 1: Stir 3.75 kg of 2 mol / L hydrofluoric acid solution, 7.5 kg of 1.5 mol / L phosphoric acid solution and 1.25 kg of 1 mol / L ammonium chloride solution evenly to obtain an acidic solution. Add 5 kg of attapulgite powder to the above acidic solution, continuously stir at 50°C for 2.5 hours, then filter and wash until the pH value of the filtrate is 7, and dry to obtain the pretreated attapulgite powder.

[0058] Step 2: Dissolve 0.32 kg of chromium nitrate and 0.12 kg of dodecyl phosphate in 3.2 kg of 4% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 80 minutes; add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution to a planetary ball mill and ball mill under nitrogen protection for 6 hours. Heat the ball-milled powder to 100°C at a rate of 5°C / min under nitrogen protection and keep it warm for 2 hours to obtain the secondary modified attapulgite powder; Step 3: Add 0.32 kg of aluminosilicate ceramic fiber, 0.16 kg of lactic acid, 0.16 kg of triphosphate, 0.4 kg of polyethylene oxide, and 4 kg of the secondarily modified attapulgite powder obtained in Step 2 into a vacuum pug mill and repeat pugging 4 times. Then, extrude the clay material through a forming extruder, and dry the formed product at 70 °C for 4 days; calcine the dried honeycomb carrier at 600 °C for 2 hours to obtain the wear-resistant attapulgite honeycomb material with self-cleaning function.

[0059] Example 4 Step 1: Stir evenly 1 kg of 3 mol / L acetic acid solution, 5 kg of 2 mol / L malonic acid solution, and 4 kg of 2 mol / L ammonium fluoride solution to obtain an acidic solution. Add 5 kg of attapulgite powder into the above acidic solution, continuously stir at 60 °C for 2 hours, then filter and wash until the pH value of the filtrate is 7, and perform drying to obtain the pretreated attapulgite powder.

[0060] Step 2: Dissolve 0.4 kg of cerium nitrate and 0.2 kg of DL-411 into 4 kg of 5% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 120 minutes; add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution into a planetary ball mill and ball mill for 8 hours under nitrogen protection. Heat the ball-milled powder to 100 °C at a rate of 5 °C / min under nitrogen protection and keep it warm for 2 hours to obtain the secondarily modified attapulgite powder; Step 3: Add 0.4 kg of silicon carbide nanofibers, 0.2 kg of lactic acid, 0.2 kg of glycerol, 0.8 kg of polyethylene oxide, and 4 kg of the secondarily modified attapulgite powder obtained in Step 2 into a vacuum pug mill and repeat pugging 5 times. Then, extrude the clay material through a forming extruder, and dry the formed product at 90 °C for 4 days; calcine the dried honeycomb carrier at 600 °C for 2 hours to obtain the wear-resistant attapulgite honeycomb material with self-cleaning function.

[0061] Comparative Example 1 In Comparative Example 1, delete the process of adding ammonium salt solution in Step 1 of Example 4, and keep other processes unchanged. The specific steps are as follows: Step 1: Stir evenly 1 kg of 3 mol / L acetic acid solution and 5 kg of 2 mol / L malonic acid solution to obtain an acidic solution. Add 5 kg of attapulgite powder into the above acidic solution, continuously stir at 60 °C for 2 hours, then filter and wash until the pH value of the filtrate is 7, and perform drying to obtain the pretreated attapulgite powder.

[0062] Step 2: Dissolve 0.4 kg of cerium nitrate and 0.2 kg of DL-411 into 4 kg of an ethanol solution with a mass concentration of 5%, and obtain a mixed solution after ultrasonic treatment for 120 minutes; Add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution into a planetary ball mill and ball mill for 8 hours under nitrogen protection, heat the milled powder to 100 °C at a rate of 5 °C per minute under nitrogen protection, and keep it warm for 2 hours to obtain the secondarily modified attapulgite powder; Step 3: Add 0.4 kg of silicon carbide nanofibers, 0.2 kg of lactic acid, 0.2 kg of glycerol, 0.8 kg of polyethylene oxide, and 4 kg of the secondarily modified attapulgite powder obtained in Step 2 into a vacuum kneading machine and knead repeatedly 5 times, then extrude the clay material through a molding extruder, and dry the molded product at 90 °C for 4 days; Calcinate the dried honeycomb carrier at 600 °C for 2 hours to obtain the attapulgite honeycomb material.

[0063] Comparative Example 2 In Comparative Example 2, delete the process of adding nitrate in Step 2 of Example 4, and keep other processes unchanged. The specific steps are as follows: Step 1: Stir evenly 1 kg of acetic acid solution with a concentration of 3 mol / L, 5 kg of malonic acid solution with a concentration of 2 mol / L, and 4 kg of ammonium fluoride solution with a concentration of 2 mol / L to obtain an acidic solution. Add 5 kg of attapulgite powder into the above acidic solution, continuously stir at 60 °C for 2 hours, then filter and wash until the pH value of the filtrate is 7, and dry to obtain the pretreated attapulgite powder.

[0064] Step 2: Dissolve 0.2 kg of DL-411 into 4 kg of an ethanol solution with a mass concentration of 5%, and obtain a mixed solution after ultrasonic treatment for 120 minutes; Add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution into a planetary ball mill and ball mill for 8 hours under nitrogen protection, heat the milled powder to 100 °C at a rate of 5 °C per minute under nitrogen protection, and keep it warm for 2 hours to obtain the secondarily modified attapulgite powder; Step 3: Add 0.4 kg of silicon carbide nanofibers, 0.2 kg of lactic acid, 0.2 kg of glycerol, 0.8 kg of polyethylene oxide, and 4 kg of the secondarily modified attapulgite powder obtained in Step 2 into a vacuum kneading machine and knead repeatedly 5 times, then extrude the clay material through a molding extruder, and dry the molded product at 90 °C for 4 days; Calcinate the dried honeycomb carrier at 600 °C for 2 hours to obtain the attapulgite honeycomb material.

[0065] Comparative Example 3 In Comparative Example 3, delete the process of adding a modifier in Step 2 of Example 4, and keep other processes unchanged. The specific steps are as follows: Step 1: Stir 1 kg of 3 mol / L acetic acid solution, 5 kg of 2 mol / L malonic acid solution and 4 kg of 2 mol / L ammonium fluoride solution evenly to obtain an acidic solution. Add 5 kg of attapulgite powder to the above acidic solution, continuously stir at 60 °C for 2 hours, then filter and wash until the pH value of the filtrate is 7, and perform drying to obtain the pretreated attapulgite powder.

[0066] Step 2: Dissolve 0.4 kg of cerium nitrate in 4 kg of 5% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 120 minutes; add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution to a planetary ball mill and ball mill under nitrogen protection for 8 hours. Heat the ball-milled powder to 100 °C at a rate of 5 °C / min under nitrogen protection and keep it warm for 2 hours to obtain the attapulgite powder after secondary modification; Step 3: Add 0.4 kg of silicon carbide nanofibers, 0.2 kg of lactic acid, 0.2 kg of glycerol, 0.8 kg of polyethylene oxide and 4 kg of the attapulgite powder after secondary modification obtained in Step 2 to a vacuum kneading machine and knead 5 times repeatedly, then extrude the mud through a molding extruder, and dry the molded product at 90 °C for 4 days; calcine the dried honeycomb carrier at 600 °C for 2 hours to obtain the attapulgite honeycomb material.

[0067] Comparative Example 4 In Comparative Example 4, the process of adding the structural aid in Step 3 of Example 4 was deleted, and other processes remained unchanged. The specific steps are as follows: Step 1: Stir 1 kg of 3 mol / L acetic acid solution, 5 kg of 2 mol / L malonic acid solution and 4 kg of 2 mol / L ammonium fluoride solution evenly to obtain an acidic solution. Add 5 kg of attapulgite powder to the above acidic solution, continuously stir at 60 °C for 2 hours, then filter and wash until the pH value of the filtrate is 7, and perform drying to obtain the pretreated attapulgite powder.

[0068] Step 2: Dissolve 0.4 kg of cerium nitrate and 0.2 kg of DL-411 in 4 kg of 5% mass concentration ethanol solution, and obtain a mixed solution after ultrasonic treatment for 120 minutes; add 4 kg of the pretreated attapulgite powder obtained in Step 1 and the above mixed solution to a planetary ball mill and ball mill under nitrogen protection for 8 hours. Heat the ball-milled powder to 100 °C at a rate of 5 °C / min under nitrogen protection and keep it warm for 2 hours to obtain the attapulgite powder after secondary modification; Step 3: Add 0.2 kg of lactic acid, 0.2 kg of glycerol, 0.8 kg of polyethylene oxide, and 4 kg of the secondary-modified attapulgite powder obtained in Step 2 into a vacuum pug mill and repeat pugging 5 times. Then, extrude the clay material through a forming extruder, and dry the formed product at 90 °C for 4 days. The dried honeycomb carrier is calcined at 600 °C for 2 hours to obtain the attapulgite honeycomb material.

[0069] The mechanical strength and dust adsorption performance of the attapulgite honeycomb materials prepared in Examples 1-4 and Comparative Examples 1-4 were tested. The test results are shown in Table 1.

[0070] Mechanical strength test: According to the standard of GB / T5072-2008, an axial compressive strength tester and a radial compressive strength tester were used to measure the axial compressive strength and radial compressive strength of the attapulgite honeycomb material samples.

[0071] Dust adsorption performance test: According to the determination part of the wear rate in "GB / T 31587-2015 Honeycomb Flue Gas Denitrification Catalyst", the carrier and device were prepared. By using 300-mesh calcium powder, the continuous scouring effect of the airflow carrying dust on the surface of the attapulgite honeycomb material in industrial or natural environments was simulated. The residual amount of dust on the surface of the attapulgite honeycomb material was measured by the following formula to evaluate its dust suppression performance. The less the residual amount, the stronger the anti-dust adhesion ability of the surface of the attapulgite honeycomb material.

[0072]

[0073] In the formula, : The initial mass of the clean attapulgite honeycomb material, : The total mass (including deposits) of the attapulgite honeycomb material after use (before cleaning), : The residual mass on the surface of the attapulgite honeycomb material after cleaning.

[0074] Table 1 Performance test results of the attapulgite honeycomb materials prepared in Examples 1-4 and Comparative Examples 1-4

[0075] Obviously, the above examples are only for clear illustration and not limitations on the examples. For those of ordinary skill in the art, other different forms of changes or variations can be made based on the above description. It is not necessary and impossible to list all examples here. And the obvious changes or variations derived therefrom are still within the protection scope of the present invention.

Claims

1. A method for preparing a wear-resistant attapulgite honeycomb material with a self-cleaning function, characterized in that: The following steps are involved: Step 1, adding attapulgite powder to an acidic solution, continuously stirring, filtering, washing until the pH value of the filtrate is 6-7, and drying to obtain pretreated attapulgite powder; The acidic solution is a mixed solution of a monoprotic acid solution, a polyprotic acid solution and an ammonium salt solution; Step 2, dissolving the metal salt and the modifier into an ethanol solution, mixing them evenly to obtain a mixed solution, and ball-milling the pretreated attapulgite powder and the mixed solution under the protection of an inert atmosphere, and keeping the mixture warm to obtain a secondary modified attapulgite powder; Step three, kneading the structural additive, molding additive, extrusion aid, binder and the secondary modified attapulgite powder into mud, extruding the obtained mud into shape, drying and calcining to obtain the wear-resistant attapulgite honeycomb material with self-cleaning function.

2. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 1, the mass ratio of the attapulgite powder to the acidic solution is 0.2-0.5:1; The monoacid is hydrochloric acid, nitric acid, hydrofluoric acid or acetic acid, and the concentration of the monoacid solution is 1.0-3.0 mol / L; The polyacid is sulfuric acid, tartaric acid, phosphoric acid or malonic acid, and the concentration of the polyacid solution is 0.5-2.0 mol / L; The ammonium salt is ammonium carbonate, ammonium sulfate, ammonium chloride or ammonium fluoride, and the concentration of the ammonium salt solution is 0.1-2.0 mol / L; The mass ratio of the monoprotic acid solution, the polyprotic acid solution and the ammonium salt solution is 0.1-0.5:0.2-0.6:0.1-0.

4.

3. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 1, the temperature of continuous stirring is 20° C. to 60° C., and the time of continuous stirring is 2 to 4 hours.

4. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 2, the metal salt is ferric nitrate, zirconium nitrate, chromium nitrate or cerium nitrate, and the mass ratio of the metal salt to the pretreated attapulgite powder is 0.05-0.1:1, and the mass of the metal salt is calculated based on the mass of the oxide; The modifier is methyl phenyl silicone resin, lauryl phosphate or aluminate coupling agent, and the mass ratio of the modifier to the pretreated attapulgite powder is 0.01-0.05:1; The mass concentration of the ethanol solution is 1% to 5%, and the mass ratio of the ethanol solution to the pretreated attapulgite powder is 0.5 to 1:

1.

5. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 2, the uniform mixing method is ultrasound, and the ultrasound time is 20 to 120 minutes; The inert atmosphere is nitrogen; The ball milling time is 4 to 8 hours; The insulation temperature is 80-100° C., the insulation time is 2-6 hours, and the temperature is increased to the insulation temperature at a heating rate of 5° C. / min.

6. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 3, the structural additive is one or more of silicon carbide nanofibers, glass fibers, and aluminum silicate ceramic fibers, and the mass ratio of the structural additive to the secondary modified attapulgite powder is 0.05-0.1:1; The molding aid is one or more of lactic acid, polyacrylic acid, and polysorbate, and the mass ratio of the structural aid to the secondary modified attapulgite powder is 0.01-0.05:1; The extrusion aid is one or more of ethylene glycol, glycerol, and triphosphate, and the mass ratio of the extrusion aid to the secondary modified attapulgite powder is 0.01-0.05:1; The binder is one or more of carboxymethyl cellulose, polyacrylamide and polyethylene oxide, and the mass ratio of the binder to the secondary modified attapulgite powder is 0.05-0.2:

1.

7. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step three, the clay kneading is repeated 3 to 5 times.

8. The method for preparing the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 1, characterized in that: In step 3, the drying temperature is 30-90° C. and the drying time is 4-6 days; The calcination temperature is 500-600° C., and the calcination time is 2-6 hours. 9 . The wear-resistant attapulgite honeycomb material with self-cleaning function prepared by the preparation method according to claim 1 .

10. Use of the wear-resistant attapulgite honeycomb material with self-cleaning function according to claim 9 as a carrier of a denitration catalyst.

Images