Honeycomb ceramic support body for low-expansion high-temperature dust removal and preparation method of honeycomb ceramic support body

Abstract

The invention discloses a low-expansion honeycomb ceramic support body for high-temperature dust removal and a preparation method thereof, the support body is formed by stacking fused quartz particles, and the support body is composed of three particle size formulas of 80-120 meshes, 120-160 meshes and 325-400 meshes, and the mass percentages of the components are 70-90%, 0-20% and 5-10%. The preparation method comprises the following steps: 1, weighing the fused quartz particles according to the formula composition, and uniformly mixing to obtain powder; step 2, adding an additive, a pore forming agent, a plasticizer, a lubricant and a binder into the powder, uniformly mixing, adding water, kneading into pug by a kneading machine, and aging to obtain qualified pug; and 3, carrying out extrusion molding on the pug, and sintering to obtain the honeycomb ceramic support body product. The technical problem that heat stability and mechanical property of traditional honeycomb ceramics for high-temperature dust removal are difficult to consider at the same time is solved, and therefore the honeycomb ceramics have good market prospects.

Description

Technical Field

[0001] This invention relates to the field of ceramic technology, and in particular to a low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method. Background Technology

[0002] Against the backdrop of the continuous and rapid development of heavy industry, industries such as steel, cement, coal, metallurgy, petroleum, chemical fiber, power, non-ferrous metals, and fertilizer continuously emit large amounts of high-temperature, dust-laden gases during their production processes. Direct emission of these untreated high-temperature, dust-laden gases will seriously endanger the environment and human health. These flue gases are characterized by a wide temperature range (600–1400℃), complex composition, high dust concentration, and fine particle size, and often contain SO2 and NO. x Corrosive gases such as Cl2 and sticky dust place extremely high demands on the corrosion resistance and thermal stability of high-temperature dust removal materials. These materials must operate in environments with drastic temperature fluctuations, strict structural constraints, and stringent sealing requirements. Therefore, high-temperature dust removal materials must possess a low coefficient of thermal expansion, their core value lying in effectively suppressing dimensional changes caused by temperature variations and the resulting destructive thermal stress. This characteristic is crucial for ensuring that high-temperature dust removal materials maintain structural integrity, dimensional stability, sealing reliability, durable filtration performance, and excellent thermal shock resistance in high-temperature environments, and is essential for ensuring the long-term, efficient, and safe operation of dust removal systems. Existing high-temperature dust removal materials mainly include cordierite, mullite, aluminum titanate, silicon carbide, zirconium oxide, silicon nitride, and their composite matrices (such as cordierite-mullite, cordierite-aluminum titanate, etc.). Among these, cordierite and silicon carbide are currently the two most commonly used materials: although cordierite has a low coefficient of thermal expansion (1.5~2.0×10⁻⁶), it still exhibits certain advantages. -6 While silicon carbide possesses high mechanical strength, it suffers from low brittleness and low thermal shock resistance. Furthermore, its honeycomb ceramics are expensive to manufacture, primarily due to the high purity requirements of raw materials and the high firing temperature. Additionally, its coefficient of thermal expansion is relatively high (4.0~4.7×10⁻⁶℃). -6 / ℃). In contrast, the coefficient of thermal expansion of fused silica is only 0.55×10 in the range of 25–800℃. -6 Its temperature is significantly lower than that of traditional materials such as silicon carbide, while also exhibiting excellent thermal shock resistance and high-temperature stability. This material also possesses outstanding acid resistance and chemical inertness, effectively preventing reactions with impurities and organic matter in high-temperature dust. Furthermore, fused silica raw materials are inexpensive and abundant, and its support preparation process is simple, requiring no complex sintering technology or equipment. Therefore, it is a highly promising high-temperature dust removal material.

[0003] CN113185273A discloses a fused silica ceramic membrane support and its preparation method, which has advantages such as high pure water flux, high ultraviolet transmittance, and simple preparation process. However, it has limitations such as insufficient support strength (<15MPa) and lack of pore size analysis. CN103011840B develops a method for preparing ultrafine fused silica micropowder for automotive honeycomb ceramic carriers, which can obtain carriers with high heat resistance and low expansion performance. However, the process is complex and requires raw material coating modification. CN109180169A discloses a ceramic membrane support that has high thermal shock resistance, high permeation flux, and high mechanical strength after firing at 1000-1200℃. However, its support aggregate needs to be uniformly coated with additives before drying and granulation, resulting in a long preparation cycle. Furthermore, its thermal expansion coefficient and acid resistance properties are not disclosed. While the honeycomb ceramic carrier for automotive exhaust purifiers prepared by CN106278207A exhibits good low expansion and high strength, it requires high purity raw materials, has a complex process, and consumes a lot of energy. CN118005419A uses wollastonite to partially or completely replace fused silica powder, significantly reducing the preparation cost of honeycomb ceramics. However, its honeycomb ceramic has a small pore size, with a maximum pore size of about 20 μm, and its strength is not disclosed, possibly due to its high porosity. The honeycomb ceramic carrier disclosed by CN117645468A has an isotropic ultra-low coefficient of thermal expansion and high thermal shock resistance, as well as a high maximum carbon loading. However, its disadvantage is that its strength is too low, with a maximum of only 3.65 MPa. The support in the literature "Preparation of Fused Silica Membrane for High Temperature Filtration and Dust Removal" has low flexural strength and a high coefficient of expansion. The support prepared in the literature "Preparation and Performance Study of Fused Silica Support" has high ultraviolet transmittance and high pure water flux, but its flexural strength is low, only 14.9 MPa. The present invention employs fused silica particle gradation technology, which achieves low expansion and high strength support through the synergistic effect of coarse, medium and fine particles. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a low-cost, high-porosity, and high-mechanical-strength low-expansion high-temperature dust removal honeycomb ceramic support and its preparation method.

[0005] This invention is achieved through the following technical solution: A low-expansion, high-temperature dust removal honeycomb ceramic support is characterized in that: the support is formed by the accumulation of fused quartz particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh, and 325-400 mesh, with a mass percentage composition of 70-90%, 0-20%, and 5-10%, respectively.

[0006] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0007] The addition amount of each component in step two is by mass percentage, namely 74-79% fused silica powder, 2-4% hexagonal boron nitride composite silicon nitride additive, 3-5% walnut powder pore-forming agent, 3-5% rapeseed oil plasticizer, 3-5% glycerin lubricant, and 6-8% hydroxypropyl methylcellulose binder.

[0008] The aging time in step two is 24–48 hours.

[0009] The firing process in step three involves heating from room temperature to 800–850°C at a heating rate of 3.2°C / min, then heating to the maximum firing temperature of 1230–1270°C at a heating rate of 2.5°C / min, holding at the maximum firing temperature for 0.5–2 hours, and then allowing it to cool naturally to room temperature.

[0010] The product obtained in step three has a flexural strength of 27.68–30.37 MPa, a porosity of 36.86–38.15%, a water absorption rate of 26.68–28.46%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0011] The present invention has the following beneficial effects: This invention innovatively employs fused silica with a particle size distribution of 37.5–187.5 μm, achieving high-strength support fabrication through the synergistic effect of coarse, medium, and fine particle packing: coarse particles construct the skeletal structure, medium particles increase packing density, and fine particles promote sintering through their surface energy advantage, not only increasing permeability but also significantly enhancing material strength. Simultaneously, the introduction of hexagonal boron nitride composite silicon nitride additives suppresses crystallization while acting as a synergistic flux, further strengthening the sintering effect. This technology achieves a breakthrough in unifying the low coefficient of thermal expansion and high mechanical strength of fused silica materials, solving the technical challenge of balancing thermal stability and mechanical properties in traditional high-temperature dust-removing honeycomb ceramic supports, thus possessing promising market prospects. Attached Figure Description

[0012] Figure 1 The XRD test results are those of the support material prepared in Example 3 of this invention. Figure 2This is the SEM detection result of the support material prepared in Example 3 of the present invention; Figure 3 This is the acid resistance test result of the support material prepared in Example 3 of the present invention; Figure 4 This is the pore size distribution test result of the support material prepared in Embodiment 3 of the present invention. Detailed Implementation

[0013] To further illustrate the present invention, the technical means and effects adopted to achieve the intended purpose of the invention, the present invention will be described in detail below with reference to preferred embodiments.

[0014] Example 1

[0015] A low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method are characterized in that: the support is formed by the stacking of fused quartz particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh and 325-400 mesh, with a mass percentage composition of 90%, 0% and 10%.

[0016] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0017] The addition amount of each component in step two is by mass percentage, namely 79% fused silica powder, 2% hexagonal boron nitride composite silicon nitride additive, 5% walnut powder pore-forming agent, 5% rapeseed oil plasticizer, 3% glycerin lubricant, and 6% hydroxypropyl methylcellulose binder.

[0018] The aging time in step two is 24 hours.

[0019] The firing process in step three involves heating from room temperature to 800°C at a rate of 3.2°C / min, then heating to the maximum firing temperature of 1270°C at a rate of 2.5°C / min, holding at the maximum firing temperature for 2 hours, and then allowing it to cool naturally to room temperature.

[0020] The product obtained in step three has a flexural strength of 27.68 MPa, a porosity of 38.15%, a water absorption rate of 28.46%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0021] Example 2

[0022] A low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method are characterized in that: the support is formed by the stacking of fused quartz particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh and 325-400 mesh, with a mass percentage composition of 70%, 20% and 10%, respectively.

[0023] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0024] The addition amount of each component in step two is by mass percentage, namely 74% fused silica powder, 3% hexagonal boron nitride composite silicon nitride additive, 5% walnut powder pore-forming agent, 5% rapeseed oil plasticizer, 5% glycerin lubricant, and 8% hydroxypropyl methylcellulose binder.

[0025] The aging time in step two is 48 hours.

[0026] The firing process in step three involves heating from room temperature to 850°C at a rate of 3.2°C / min, then heating to the maximum firing temperature of 1230°C at a rate of 2.5°C / min, holding at the maximum firing temperature for 2 hours, and then allowing it to cool naturally to room temperature.

[0027] The product obtained in step three has a flexural strength of 30.37 MPa, a porosity of 36.86%, a water absorption rate of 28.46%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0028] Example 3

[0029] A low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method are characterized in that: the support is formed by the stacking of fused quartz particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh and 325-400 mesh, with a mass percentage composition of 85%, 10% and 5%, respectively.

[0030] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0031] The addition amount of each component in step two is by mass percentage, namely 77% fused silica powder, 3% hexagonal boron nitride composite silicon nitride additive, 4% walnut powder pore-forming agent, 5% rapeseed oil plasticizer, 4% glycerin lubricant, and 7% hydroxypropyl methylcellulose binder.

[0032] The aging time in step two is 36 hours.

[0033] The firing process in step three is as follows: the temperature is increased from room temperature to 830°C at a heating rate of 3.2°C / min, then increased to the maximum firing temperature of 1250°C at a heating rate of 2.5°C / min, and held at the maximum firing temperature for 1 hour, and then allowed to cool naturally to room temperature.

[0034] The product obtained in step three has a flexural strength of 30.37 MPa, a porosity of 37.24%, a water absorption rate of 27.34%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0035] from Figure 1 As shown in the figure, the diffraction peaks of the product all exhibit a bun-shaped peak pattern, indicating that no crystal precipitation has occurred.

[0036] from Figure 2 As can be seen from the content shown, the pores of the product are mostly interconnected pores, and there are many pores, which indicates that the support has a porous structure.

[0037] from Figure 3 The results show that after 8 hours of hydrothermal corrosion in a 20% sulfuric acid solution, the mass loss of the product was only 0.26%, and the flexural strength decreased by only 17.62%, indicating that the sample has excellent acid resistance.

[0038] from Figure 4 As shown in the figure, the pore size of the product is uniformly distributed, mostly between 35 and 45 μm.

[0039] Example 4

[0040] A low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method are characterized in that: the support is formed by the stacking of fused quartz particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh and 325-400 mesh, with a mass percentage composition of 80%, 10% and 10%, respectively.

[0041] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0042] The addition amount of each component in step two is by mass percentage, namely 78.5% fused silica powder, 4% hexagonal boron nitride composite silicon nitride additive, 3% walnut powder pore-forming agent, 3% rapeseed oil plasticizer, 5% glycerin lubricant, and 6.5% hydroxypropyl methylcellulose binder.

[0043] The aging time in step two is 40 hours.

[0044] The firing process in step three involves heating from room temperature to 820°C at a rate of 3.2°C / min, then heating to the maximum firing temperature of 1240°C at a rate of 2.5°C / min, holding at the maximum firing temperature for 2 hours, and then allowing it to cool naturally to room temperature.

[0045] The product obtained in step three has a flexural strength of 28.62 MPa, a porosity of 37.49%, a water absorption rate of 26.68%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0046] Example 5

[0047] A low-expansion, high-temperature dust removal honeycomb ceramic support and its preparation method are characterized in that: the support is formed by the stacking of fused silica particles, and is composed of three particle size formulations of 80-120 mesh, 120-160 mesh and 325-400 mesh, with a mass percentage composition of 78%, 14% and 8%, respectively.

[0048] The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support is characterized by comprising the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

[0049] The addition amount of each component in step two is by mass percentage, namely 77.5% fused silica powder, 3.5% hexagonal boron nitride composite silicon nitride additive, 4.5% walnut powder pore-forming agent, 4% rapeseed oil plasticizer, 4% glycerin lubricant, and 6.5% hydroxypropyl methylcellulose binder.

[0050] The aging time in step two is 36 hours.

[0051] The firing process in step three involves heating from room temperature to 840°C at a rate of 3.2°C / min, then heating to the maximum firing temperature of 1270°C at a rate of 2.5°C / min, holding at the maximum firing temperature for 0.5 hours, and then allowing it to cool naturally to room temperature.

[0052] The product obtained in step three has a flexural strength of 30.12 MPa, a porosity of 37.05%, a water absorption rate of 27.84%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

[0053] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions and improvements made within the principles and spirit of the present invention are included within the protection scope of the present invention.

Claims

1. A honeycomb ceramic support for low-expansion high-temperature dust removal, characterized in that: The support is formed by the accumulation of fused silica particles, and is composed of three particle size formulations: 80-120 mesh, 120-160 mesh, and 325-400 mesh, with a mass percentage composition of 70-90%, 0-20%, and 5-10%, respectively.

2. The method for preparing the low-expansion high-temperature dust removal honeycomb ceramic support according to claim 1, characterized in that... Includes the following steps: Step 1: Weigh the fused silica particles according to the formula and mix them evenly to obtain powder; Step 2: Add additives, pore-forming agents, plasticizers, lubricants and binders to the powder, mix evenly, add water and knead into mud using a kneader, and obtain qualified mud after aging; Step 3: The clay obtained in Step 2 is extruded, molded, and fired to obtain a honeycomb ceramic support product.

3. The preparation method according to claim 2, characterized in that: The addition amount of each component in step two is by mass percentage, namely 74-79% fused silica powder, 2-4% hexagonal boron nitride composite silicon nitride additive, 3-5% walnut powder pore-forming agent, 3-5% rapeseed oil plasticizer, 3-5% glycerin lubricant, and 6-8% hydroxypropyl methylcellulose binder.

4. The preparation method according to claim 2, characterized in that: The aging time in step two is 24–48 hours.

5. The preparation method according to claim 2, characterized in that: The firing process in step three involves heating from room temperature to 800–850°C at a heating rate of 3.2°C / min, then heating to the maximum firing temperature of 1230–1270°C at a heating rate of 2.5°C / min, holding at the maximum firing temperature for 0.5–2 hours, and then allowing it to cool naturally to room temperature.

6. The preparation method according to claim 2, characterized in that: The product obtained in step three has a flexural strength of 27.68–30.37 MPa, a porosity of 36.86–38.15%, a water absorption rate of 26.68–28.46%, and a coefficient of thermal expansion of 0.55 × 10⁻⁶ at room temperature to 800°C. -6 / ℃.

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