Honeycomb ceramic carrier and preparation method therefor, and tail-gas catalysis core body

Abstract

Provided in the present invention are a honeycomb ceramic carrier and a preparation method therefor, and a tail-gas catalysis core body. The honeycomb ceramic carrier contains silicon carbide, and the crystalline phase of silicon carbide comprises 4H-SiC and 6H-SiC, wherein the mass of 4H-SiC accounts for 13%-30% of the total mass of the honeycomb ceramic carrier, and the mass of 6H-SiC accounts for 40%-55% of the total mass of the honeycomb ceramic carrier. The porosity of the honeycomb ceramic carrier is 45%-70%, preferably 50%-65%. The honeycomb ceramic carrier provided in the present invention can be cost-effective while also ensuring relatively good porosity, pore volume and thermal diffusion coefficient.

Description

Honeycomb ceramic carrier, preparation method thereof and tail gas catalytic core TECHNICAL FIELD

[0001] The present application relates to the field of honeycomb ceramic carriers, in particular to a honeycomb ceramic carrier, a preparation method thereof and a tail gas catalytic core. BACKGROUND

[0002] In some current technologies, high-purity silicon carbide is used as the main aggregate in honeycomb ceramic traps for efficient trapping of diesel particulate matter. Among them, 4H-SiC, 6H-SiC, 3C-SiC and 15R-SiC are different crystal forms of silicon carbide, each having unique physical and chemical properties that determine their suitability and advantages in applications such as honeycomb ceramics. Here are some comparisons of these crystal forms in honeycomb ceramics: 3C-SiC has a cubic lattice structure, which is different from other hexagonal SiC crystal forms, and has relatively low thermal conductivity, which may not be suitable for applications requiring extremely high thermal conductivity; 15R-SiC has less research and fewer applications compared to other crystal forms, and needs further research. 4H-SiC and 6H-SiC are very suitable for use in honeycomb ceramics at high temperatures due to their high thermal conductivity and good high-temperature stability. In general, 4H-SiC and 6H-SiC are more commonly used in high-temperature applications such as honeycomb ceramics due to their excellent physical properties. The application potential of 15R-SiC in honeycomb ceramics needs further exploration. The choice of each crystal form will depend on the specific application requirements and performance requirements. The SiC honeycomb ceramic materials currently produced on the market all use high-purity SiC, with a mass fraction of 6H-SiC of more than 90%, resulting in high cost.

[0003] Therefore, it is an urgent problem in the field to seek a honeycomb ceramic carrier with higher cost performance. SUMMARY

[0004] The present application aims to provide a honeycomb ceramic carrier, a preparation method thereof and a tail gas catalytic core, which have higher cost performance while ensuring better porosity, pore volume and thermal diffusivity.

[0005] To achieve the above-mentioned purpose, the present application provides the following technical solutions:

[0006] A honeycomb ceramic carrier contains silicon carbide, the crystal phase of the silicon carbide includes 4H-SiC and 6H-SiC, the mass of the 4H-SiC accounts for 13% to 30% of the total mass of the honeycomb ceramic carrier, the mass of the 6H-SiC accounts for 40% to 55% of the total mass of the honeycomb ceramic carrier, and the porosity of the honeycomb ceramic carrier is 45% to 70%, preferably 50% to 65%.

[0007] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC is 1:(2-4), preferably 1:(2-3).

[0008] In some embodiments of the present application, the honeycomb ceramic carrier further contains elemental silicon, and the mass of the elemental silicon accounts for 10-25%, preferably 15-25% of the total mass of the honeycomb ceramic carrier.

[0009] And / or, the honeycomb ceramic carrier further contains silicon dioxide, and the mass of the silicon dioxide accounts for 5-25%, preferably 8-18% of the total mass of the honeycomb ceramic carrier.

[0010] In some embodiments of the present application, the honeycomb ceramic carrier has a thermal diffusivity of 5-25 mm 2 / s, preferably 16-20 mm 2 / s.

[0011] In some embodiments of the present application, the raw material of the honeycomb ceramic carrier comprises a main material and an auxiliary material, wherein the main material comprises two or three of the following: a first silicon carbide powder with a particle size of 30-50 μm, a second silicon carbide powder with a particle size of 15-30 μm, and a third silicon carbide powder with a particle size less than 15 μm.

[0012] Preferably, the particle size of the first silicon carbide powder is 35-45 μm, the particle size of the second silicon carbide powder is 20-30 μm, and the particle size of the third silicon carbide powder is 4-12 μm.

[0013] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is (0.15-0.25):1, preferably (0.17-0.23):1.

[0014] And / or, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is (0.3-0.4):1, preferably (0.3-0.35):1.

[0015] And / or, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is (0.15-0.25):1, preferably (0.15-0.2):1.

[0016] In some embodiments of the present application, the main material further comprises an elemental silicon powder, a metal oxide, and / or clay, and / or the auxiliary material comprises a binder and a pore-forming agent.

[0017] Preferably, the mass of the silicon carbide powder accounts for 60-90% of the mass of the main material, more preferably 75-85%, the mass of the elemental silicon powder accounts for 15-25% of the mass of the main material, more preferably 15-20%, the mass of the metal oxide accounts for 0.1-2.5% of the mass of the main material, more preferably 0.5-2%, the mass of the clay accounts for 0.1-2% of the mass of the main material, more preferably 0.5-1.5%, the mass of the binder accounts for 4-10% of the mass of the main material, more preferably 5-8%, and the mass of the pore-forming agent accounts for 2-30% of the mass of the main material, more preferably 5-15%.

[0018] In some embodiments of the present application, the mass of the first silicon carbide powder accounts for 0-50% of the mass of the main material, more preferably 4-40%, the mass of the second silicon carbide powder accounts for 25-75% of the mass of the main material, more preferably 30-70%, and the mass of the third silicon carbide powder accounts for 0-5% of the mass of the main material, more preferably 1-4%.

[0019] Alternatively, the mass ratio of the first, second and third silicon carbide powders is (0-50):(30-75):(0-5), and the mass of the first and third silicon carbide powders is not zero at the same time.

[0020] In some embodiments of the present application, the pore-forming agent is selected from at least one of polyacrylic acid, polyacrylamide, polyvinyl alcohol, polymethyl methacrylate microspheres, starch, and expanded microspheres.

[0021] And / or, the D10 of the pore-forming agent is ≥10 μm and the D90 is ≤35 μm.

[0022] In some embodiments of the present application, the particle size specification of the elemental silicon powder is D10>1 μm and D90<15 μm, the particle size specification of the metal oxide is D10>2.8 μm and D90<8 μm, and the particle size specification of the clay is D10>2 μm and D90<17 μm.

[0023] And / or, the binder is selected from at least one of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose.

[0024] In some embodiments of the present application, the metal oxide is at least one selected from calcium oxide, sodium oxide, magnesium oxide, aluminum oxide, barium oxide, iron oxide, and copper oxide.

[0025] In some embodiments of the present application, the honeycomb ceramic carrier has a channel density of 200-400 cpsi, preferably 275-305 cpsi.

[0026] In some embodiments of the present application, the median pore size D50 of the honeycomb ceramic carrier is 10-30 microns, preferably 10-18 microns.

[0027] In some embodiments of the present application, the pore volume of the honeycomb ceramic carrier is 0.18-0.6 mL / g, preferably 0.2-0.3 mL / g.

[0028] To achieve the above-mentioned purposes, the present application further provides the following technical solutions:

[0029] A method for preparing the honeycomb ceramic carrier described above, the method comprising the following steps:

[0030] S1, providing raw materials, the raw materials comprising silicon carbide powder, elemental silicon powder, metal oxide, clay, binder and pore-forming agent;

[0031] S2, mixing, kneading, pugging, extrusion molding, drying, cutting, and sintering the raw materials in step S1 to obtain a ceramic monolith;

[0032] S3, sequentially assembling, skinning, and skinning the ceramic monolith to obtain the honeycomb ceramic carrier.

[0033] In some embodiments of the present application, the silicon carbide powder comprises two or three of the following: first silicon carbide powder with a particle size of 30-50 microns, second silicon carbide powder with a particle size of 15-30 microns, and third silicon carbide powder with a particle size of less than 15 microns.

[0034] Preferably, the particle size of the first silicon carbide powder is 35-45 microns, the particle size of the second silicon carbide powder is 20-30 microns, and the particle size of the third silicon carbide powder is 4-12 microns.

[0035] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is (0.15-0.25):1, preferably (0.17-0.23):1;

[0036] And / or, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is (0.3-0.4):1, preferably (0.3-0.35):1;

[0037] And / or, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is (0.15-0.25):1, preferably (0.15-0.2):1.

[0038] In some embodiments of the present application, the step S2 further has a pore blocking step between sintering and drying.

[0039] In some embodiments of the present application, the mixing of the raw materials in step S2 is performed by a dry mixing followed by a wet mixing;

[0040] And / or, in step S2, the drying is performed by a microwave drying.

[0041] And / or, in step S2, the sintering is performed by an oxygen-free sintering followed by an oxygen sintering.

[0042] To achieve the above object, the present application further provides the following technical solutions.

[0043] A tail gas catalytic core, comprising:

[0044] The honeycomb ceramic carrier described above or prepared by the method described above; and

[0045] A catalyst coated on the inner wall surface of the pore of the honeycomb ceramic carrier.

[0046] Other applicable fields will become apparent from the description provided in the present disclosure.

[0047] The description in the summary and specific examples are only intended to illustrate and not intended to limit the scope of the present disclosure.

[0048] Compared with the prior art, the technical solutions provided by the present application have the following beneficial effects:

[0049] The present application provides a honeycomb ceramic structure of silicon carbide with a special crystal phase ratio, which achieves the effect of low cost and excellent performance, that is, by using a honeycomb ceramic carrier of 4HSiC-6HSiC material with a specific crystal phase ratio, good performance is obtained, especially the thermal diffusion coefficient is 5-25mm 2 / s, which makes the performance of this honeycomb ceramic carrier reach the level of the prior art, but because the specific 4HSiC-6HSiC crystal phase ratio of silicon carbide is set, the production cost is low. Especially in the case of high porosity, the pore volume and thermal diffusion coefficient of the honeycomb ceramic carrier provided by the present application are better, and it has higher cost performance. BRIEF DESCRIPTION OF DRAWINGS

[0050] In order to more clearly illustrate the technical solutions in the embodiments of the present application, the drawings needed in the embodiment description will be briefly introduced below. Obviously, the drawings in the following description are only some embodiments of the present application, and other drawings can be obtained by those skilled in the art without creative labor.

[0051] Fig. 1 is a flow chart of the preparation method of the honeycomb ceramic carrier provided by the first embodiment of the present application;

[0052] Figure 2 is an XRD pattern of high purity silicon carbide, silicon carbide primary powder, silicon carbide secondary powder, and silicon carbide tertiary powder feedstock according to a second embodiment of the present application;

[0053] Figure 3 is an XRD pattern of the finished support of Comparative Example 1, Comparative Example 2, Example 1, Example 5, and Example 8. DETAILED DESCRIPTION

[0054] The technical solutions in the embodiments of the present application will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present application, rather than all the embodiments. Based on the embodiments in the present application, all the other embodiments obtained by a person skilled in the art without any creative work should fall within the protection scope of the present application. It should be understood that the specific embodiments described herein are only used to illustrate and explain the present application, and are not used to limit the present application.

[0055] Any specific numerical values (including the endpoints of numerical ranges) disclosed herein are not to be construed as limiting, but rather as approximations. It is to be understood that slight variations from the numerical values disclosed in this specification can be considered to be within the scope of the disclosure. It is also to be understood that the disclosure is not limited to the specific numerical values recited, but rather that the disclosure covers all values that fall within the range of the recited values. Furthermore, it is to be understood that the disclosure even more broadly covers all values that fall within the range of the recited values, as well as any and all sub-ranges that fall within the range of the recited values. In other words, the disclosure is not limited to the specific numerical values recited, but rather, the disclosure covers all values that fall within the range of the recited values, as well as any and all sub-ranges that fall within the range of the recited values.

[0056] The terminology used by the present disclosure is intended to be interpreted in only a descriptive manner and not as a limitation on the scope of the particular exemplary embodiments. As used throughout this disclosure, the singular forms "a," "an," and "the" include plural reference unless the context clearly dictates otherwise. The terms "comprises," "comprising," "includes," "including," "contains," and "containing," are inclusive and therefore specify the presence of stated features, integers, compositions, steps, operations, elements, and / or components but do not preclude the presence or addition of one or more other features, integers, compositions, steps, operations, elements, components, and / or groups thereof. Although the open-ended term "comprising," when used in the description or the claims, is intended to be interpreted to allow for the inclusion of one or more additional features, elements, steps, operations, components, and / or groups thereof, in certain aspects the term is instead read as a more restrictive term, such as "consisting of or "consisting essentially of. Thus, any given embodiment reciting a composition, material, component, element, feature, integer, operation, and / or process step is intended to encompass not only the described embodiment but also embodiments that consist of or consist essentially of the described embodiment, in the case of "consisting of, any additional composition, material, component, element, feature, integer, operation, and / or process step that does not materially affect the basic and novel characteristics of the described embodiment is excluded from the embodiment, while in the case of "consisting essentially of, any additional composition, material, component, element, feature, integer, operation, and / or process step that does not materially affect the basic and novel characteristics of the described embodiment can be included in the embodiment.

[0057] Any method steps, processes, and operations described in the present disclosure are not to be construed as necessarily requiring their performance in the particular order in which they are discussed or illustrated unless expressly stated as such. It is also to be understood that additional or alternative steps can be employed, unless otherwise stated.

[0058] In this application, unless otherwise stated, any of the terms "about," "substantially," and "approximately" mean that the recited characteristie or value need not be exact, but can have a tolerance that is acceptable in the art to which the disclosure pertains. In this application, except as otherwise expressly indicated, any of the terms "about," "substantially," and "approximately" mean that the recited characteristic or value need not be exact, but can have a tolerance that is acceptable in the art to which the disclosure pertains. In this application, except as otherwise expressly indicated, any of the terms "about," "substantially," and "approximately" mean that the recited characteristic or value need not be exact, but can have a tolerance that is acceptable in the art to which the disclosure pertains. In this application, except as otherwise expressly indicated, any of the terms "about," "substantially," and "approximately" mean that the recited characteristic or value need not be exact, but can have a tolerance that is acceptable in the art to which the disclosure pertains.

[0059] Unless otherwise defined, all terms used in this disclosure, including technical or scientific terms, have the same meaning as commonly understood by one of ordinary skill in the art to which this disclosure pertains. If any of the terms in this disclosure are defined in this document and are different from the commonly understood meanings of the same terms, the definitions provided in this document are prevail.

[0060] Unless otherwise stated, references hereinafter to % mean wt.%.

[0061] It is worth mentioning that the definition or explanation of some parameters in the present application is as follows:

[0062] Pore volume, also known as pore volume, refers to the total volume of pores per unit mass of porous solid, which is one of the important characteristic values of porous structure adsorbent or catalyst, and is usually expressed by the volume of adsorbent micropores per unit weight of adsorbent, with the unit of cm 3 / g.

[0063] Thermal diffusivity, usually represented by the symbol α, is a physical quantity describing the ability of temperature propagation within a material, with the unit of square meter per second (unit symbol m 2 / s), and can be calculated by the formula α = λ / ρc, where λ represents the thermal conductivity (unit symbol W / (m·K)), ρ is the density (unit symbol kg / m 3 ), and c is the specific heat capacity (unit symbol J / (kg·K))11. Thermal diffusivity reflects the propagation speed of temperature change within a material when it is subjected to thermal stimulation; the larger the α value, the greater the ability of the material to flatten the temperature, i.e., the more rapidly the temperature change propagates within the material.

[0064] It is worth mentioning that, in the cumulative pore volume of the partition wall determined by the mercury intrusion method, the pore diameter at which the cumulative pore volume is 10% of the total pore volume is D10, the pore diameter at which the cumulative pore volume is 50% of the total pore volume is D50, i.e., the median pore diameter, and the pore diameter at which the cumulative pore volume is 90% of the total pore volume is D90.

[0065] In the context of the present disclosure, the cell density refers to the number of cells per square inch in the cross section of the honeycomb ceramic carrier, with the unit of cpsi. The cells here include both open cells and closed cells.

[0066] The first aspect

[0067] A honeycomb ceramic carrier contains silicon carbide, the crystal phase of the silicon carbide includes 4H-SiC and 6H-SiC, the mass of the 4H-SiC accounts for 13% to 30% of the total mass of the honeycomb ceramic carrier, the mass of the 6H-SiC accounts for 40% to 55% of the total mass of the honeycomb ceramic carrier, and the porosity of the honeycomb ceramic carrier is 45% to 70%, preferably 50 to 65%.

[0068] The above honeycomb ceramic carrier provided by the present application has higher cost performance while ensuring better porosity, pore volume, and thermal diffusivity.

[0069] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC is 1:(2-4), preferably 1:2.

[0070] In some embodiments of the present application, the honeycomb ceramic carrier further contains elemental silicon, and the mass of the elemental silicon accounts for 10-25%, preferably 15-25% of the total mass of the honeycomb ceramic carrier.

[0071] In some embodiments of the present application, the honeycomb ceramic carrier further contains silicon dioxide, and the mass of the silicon dioxide accounts for 5-25%, preferably 8-18% of the total mass of the honeycomb ceramic carrier.

[0072] In some embodiments of the present application, the honeycomb ceramic carrier has a thermal diffusivity of 5-25 mm 2 / s, preferably 16-20 mm 2 / s.

[0073] In some embodiments of the present application, the raw material of the honeycomb ceramic carrier comprises a main material and an auxiliary material, wherein the main material comprises two or three of the following: a first silicon carbide powder with a particle size of 30-50 μm, a second silicon carbide powder with a particle size of 15-30 μm, and a third silicon carbide powder with a particle size less than 15 μm.

[0074] In some embodiments of the present application, the particle size of the first silicon carbide powder is 35-45 μm, the particle size of the second silicon carbide powder is 20-30 μm, and the particle size of the third silicon carbide powder is 4-12 μm.

[0075] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is (0.15-0.25):1, preferably (0.17-0.23):1.

[0076] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is (0.3-0.4):1, preferably (0.3-0.35):1.

[0077] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is (0.15-0.25):1, preferably (0.15-0.2):1.

[0078] In some embodiments of the present application, the main material further comprises an elemental silicon powder, a metal oxide, and clay.

[0079] In some embodiments of the present application, the auxiliary material comprises a binder and a pore-forming agent.

[0080] In some embodiments of the present application, the mass of the silicon carbide powder is 60-90% of the mass of the main material, more preferably 75-85%, the mass of the elemental silicon powder is 15-25% of the mass of the main material, more preferably 15-20%, the mass of the metal oxide is 0.1-2.5% of the mass of the main material, more preferably 0.5-2%, the mass of the clay is 0.1-2% of the mass of the main material, more preferably 0.5-1.5%, the mass of the binder is 4-10% of the mass of the main material, more preferably 5-8%, and the mass of the pore-forming agent is 2-30% of the mass of the main material, more preferably 5-15%. In the context of the present application, the total mass of the above-mentioned main materials, i.e. the silicon carbide powder, the elemental silicon powder, the metal oxide and the clay, is always 100%, i.e. the total mass of the main materials refers to the total mass of the silicon carbide powder, the elemental silicon powder, the metal oxide and the clay.

[0081] In some embodiments of the present application, the mass of the first silicon carbide powder is 0-50% of the mass of the main material, more preferably 4-40%, the mass of the second silicon carbide powder is 25-75% of the mass of the main material, more preferably 30-70%, and the mass of the third silicon carbide powder is 0-5% of the mass of the main material, more preferably 1-4%.

[0082] Alternatively, the mass ratio of the first, second and third silicon carbide powders is (0-50):(30-75):(0-5), and the mass of the first and third silicon carbide powders is not zero at the same time.

[0083] In some embodiments of the present application, the pore-forming agent is selected from at least one of polyacrylic acid, polyacrylamide, polyvinyl alcohol, polymethyl methacrylate microspheres, starch and expanded microspheres.

[0084] In some embodiments of the present application, the D10 of the pore-forming agent is ≥10 μm and the D90 is ≤35 μm.

[0085] In some embodiments of the present application, the particle size specification of the elemental silicon powder is D10>1 μm and D90<15 μm.

[0086] In some embodiments of the present application, the particle size specification of the metal oxide is D10>2.8 μm and D90<8 μm.

[0087] In some embodiments of the present application, the particle size specification of the clay is D10>2 μm and D90<17 μm.

[0088] In some embodiments of the present application, the binder is selected from at least one of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, methyl cellulose and ethyl cellulose.

[0089] In some embodiments of the present application, the metal oxide is at least one selected from calcium oxide, sodium oxide, magnesium oxide, aluminum oxide, barium oxide, iron oxide, and copper oxide.

[0090] In some embodiments of the present application, the honeycomb ceramic carrier has a pore density of 200-400 cpsi, preferably 275-305 cpsi.

[0091] In some embodiments of the present application, the honeycomb ceramic carrier has a pore size of 10-30 μm, preferably 10-18 μm.

[0092] In some embodiments of the present application, the honeycomb ceramic carrier has a porosity of 30-70%, preferably 35-60%.

[0093] In some embodiments of the present application, the honeycomb ceramic carrier has a pore volume of 0.18-0.6 mL / g, preferably 0.2-0.3 mL / g.

[0094] It is worth mentioning that the honeycomb ceramic carrier provided by the present application can be used as a tail gas catalytic core, and thus can be used for catalytic purification treatment of tail gas or exhaust gas, more specifically, for catalytic purification treatment of exhaust gas generated by incomplete combustion of diesel.

[0095] In some embodiments of the present application, the honeycomb ceramic carrier has a plurality of compartments extending in the longitudinal direction thereof, a part of the compartments are blocked at one end of the longitudinal direction of the honeycomb ceramic carrier, and another part of the compartments are blocked at the other end, a partition wall is arranged between the two types of compartments to be adjacent, and a plurality of gas holes for gas exchange between the two compartments are arranged on the partition wall.

[0096] The second aspect

[0097] Referring to FIG. 1, a method for preparing the honeycomb ceramic carrier described above comprises the following steps: S1, providing raw materials, wherein the raw materials comprise silicon carbide powder, elemental silicon powder, metal oxide, clay, binder, and pore-forming agent; S2, mixing, kneading, pugging, extrusion molding, drying, cutting, and sintering the raw materials in step S1 to obtain a ceramic unit body; and S3, sequentially carrying out splicing, skin grinding, and skin grafting treatment on the ceramic unit body to obtain the honeycomb ceramic carrier.

[0098] In some embodiments of the present application, the silicon carbide powder comprises two or three of the following: first silicon carbide powder having a particle size of 30-50 μm, second silicon carbide powder having a particle size of 15-30 μm, and third silicon carbide powder having a particle size of less than 15 μm.

[0099] In some embodiments of the present application, the particle size of the first silicon carbide powder is 35-45 μm, the particle size of the second silicon carbide powder is 20-30 μm, and the particle size of the third silicon carbide powder is 4-12 μm.

[0100] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is (0.15-0.25):1, preferably (0.17-0.23):1.

[0101] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is (0.3-0.4):1, preferably (0.3-0.35):1.

[0102] In some embodiments of the present application, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is (0.15-0.25):1, preferably (0.15-0.2):1.

[0103] In some embodiments of the present application, the step S2 further comprises a hole blocking step between the sintering and the drying.

[0104] In some embodiments of the present application, the mixing of the raw materials in the step S2 is performed by a dry mixing followed by a wet mixing.

[0105] In some embodiments of the present application, the drying in the step S2 is performed by a microwave drying.

[0106] In some embodiments of the present application, the sintering in the step S2 is performed by an oxygen-free sintering followed by an oxygen sintering.

[0107] Third aspect

[0108] A tail gas catalytic core body, comprising: the honeycomb ceramic carrier as described above or prepared by the method as described above; and a catalyst coated on the inner wall surface of the pore of the honeycomb ceramic carrier.

[0109] It is worth mentioning that the tail gas catalytic core body provided by the present application can be used for the purification and catalytic treatment of tail gas or exhaust gas, more specifically, for the catalytic purification and treatment of exhaust gas generated by incomplete combustion of diesel.

[0110] Example 1

[0111] In this embodiment, the proportion of silicon carbide powder in the main material is 80wt.%, wherein the proportion of the first silicon carbide powder is 47wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.2:1, the proportion of the second silicon carbide powder is 33wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.3:1, the proportion of elemental silicon powder is 18wt.%, the proportion of clay is 0.5wt.%, the proportion of metal oxide powder is 1.5wt.%, the proportion of binder is 6.8wt.%, and the proportion of pore-forming agent is 2.2wt.%; the above binder is polyethylene glycol; the above pore-forming agent is polyacrylic acid and starch, and the mass ratio of polyacrylic acid to starch in the pore-forming agent is 1:1; and the above metal oxide is calcium oxide.

[0112] All the above raw materials are added to a plowshare mixer for dry mixing, wherein the dry mixing time is 15min and the dry mixing speed is 95rpm; after dry mixing, water is added for wet mixing, wherein the proportion of water in the main material is 45.2wt.%, the wet mixing time is 5min, and the wet mixing speed is 95rpm; after wet mixing, the obtained mixture is put into a double-shaft kneader for kneading, and the kneading time is 60min; after kneading, the mixture is subjected to mud practice, and then is put into an extruder to obtain unit bodies by extrusion; the unit bodies are sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, oxidizing sintering, and then are sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0113] Example 2

[0114] In this embodiment, the proportion of silicon carbide powder in the main material is 75wt.%, wherein the proportion of the first silicon carbide powder is 43wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.18:1, the proportion of the second silicon carbide powder is 32wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.3:1, the proportion of elemental silicon powder is 20.8wt.%, the proportion of clay is 1.5wt.%, the proportion of metal oxide powder is 2.2wt.%, the proportion of binder is 6.8wt.%, and the proportion of pore-forming agent is 2.2wt.%; the above binder is carboxymethyl cellulose; the above pore-forming agent is polylactic acid and starch, and the mass ratio of polylactic acid to starch in the pore-forming agent is 1:1; and the above metal oxide is sodium oxide.

[0115] The above-mentioned raw materials were added into a plow mixer for dry mixing, wherein the dry mixing time was 15 min, and the dry mixing speed was 95 rpm; after the dry mixing was completed, water was added for wet mixing, wherein the water accounted for 45.2 wt.% of the main material, the wet mixing time was 5 min, and the wet mixing speed was 95 rpm; after the wet mixing was completed, the obtained mixture was put into a double shaft kneader for kneading, and the kneading time was 60 min; after the kneading was completed, the dough was rolled, and after the rolling was completed, the dough was put into an extruder to obtain unit bodies by extrusion; the unit bodies were sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then were sequentially subjected to splicing, skin grinding, and skin grafting to obtain the honeycomb ceramic carrier.

[0116] Example 3

[0117] In this example, the proportion of silicon carbide powder was 77 wt.%, wherein the proportion of the first silicon carbide powder was 38 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder was 0.17:1, the proportion of the second silicon carbide powder was 39 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder was 0.31:1, the proportion of elemental silicon powder was 19.8 wt.%, the proportion of clay was 1.5 wt.%, the proportion of the main material of the metal oxide powder was 1.7 wt.%, the proportion of the binder was 6.8 wt.%, and the proportion of the pore-forming agent was 7 wt.%; the above-mentioned binder was methyl cellulose; the above-mentioned pore-forming agent was polyvinyl butylal and starch, and the mass ratio of polyvinyl butylal to starch in the pore-forming agent was 1:1; and the above-mentioned metal oxide was magnesium oxide.

[0118] The above-mentioned raw materials were added into a plow mixer for dry mixing, wherein the dry mixing time was 15 min, and the dry mixing speed was 95 rpm; after the dry mixing was completed, water was added for wet mixing, wherein the water accounted for 45.2 wt.% of the main material, the wet mixing time was 5 min, and the wet mixing speed was 95 rpm; after the wet mixing was completed, the obtained mixture was put into a double shaft kneader for kneading, and the kneading time was 60 min; after the kneading was completed, the dough was rolled, and after the rolling was completed, the dough was put into an extruder to obtain unit bodies by extrusion; the unit bodies were sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then were sequentially subjected to splicing, skin grinding, and skin grafting to obtain the honeycomb ceramic carrier.

[0119] Example 4

[0120] In this embodiment, the proportion of silicon carbide powder in the main material is 80wt.%, wherein the proportion of the first silicon carbide powder is 35wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.16:1, the proportion of the second silicon carbide powder is 40wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.33:1, the proportion of the third silicon carbide powder is 5wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.18:1, the proportion of elemental silicon powder is 18wt.%, the proportion of clay is 0.5wt.%, the proportion of metal oxide powder is 1.5wt.%, the proportion of binder is 6.8wt.%, and the proportion of pore-forming agent is 9.3wt.%; the above-mentioned binder is ethyl cellulose; the above-mentioned pore-forming agent is polyacrylic acid, starch and polyvinyl alcohol, and the mass ratio of polyacrylic acid, starch and polyvinyl alcohol in the pore-forming agent is 1:1:1; and the above-mentioned metal oxide is copper oxide.

[0121] All the above-mentioned raw materials are added into a plowshare mixer for dry mixing, wherein the dry mixing time is 15min and the dry mixing speed is 95rpm; after the dry mixing is completed, water is added for wet mixing, wherein the proportion of water in the main material is 45.5wt.%, the wet mixing time is 5min and the wet mixing speed is 95rpm; after the wet mixing is completed, the obtained mixture is put into a double-shaft kneader for kneading, and the kneading time is 60min; after the kneading is completed, the mixture is subjected to mud refining, and then is put into an extruder to obtain unit bodies by extrusion; the unit bodies are sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, oxidizing sintering, and then are sequentially subjected to splicing, skin grinding and skin grafting to obtain a honeycomb ceramic carrier.

[0122] Example 5

[0123] In this embodiment, the proportion of silicon carbide powder in the main material is 83wt.%, wherein the proportion of the first silicon carbide powder is 35wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.2:1, the proportion of the second silicon carbide powder is 45wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.36:1, the proportion of the third silicon carbide powder is 5wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.22:1, the proportion of elemental silicon powder is 15.2wt.%, the proportion of clay is 0.5wt.%, the proportion of metal oxide powder is 1.3wt.%, the proportion of binder is 6.8wt.%, and the proportion of pore-forming agent is 10.1wt.%; the above-mentioned binder is polyethylene glycol; the above-mentioned pore-forming agent is polyvinyl acetate, starch and polyvinyl alcohol, and the mass ratio of polyvinyl acetate, starch and polyvinyl alcohol in the pore-forming agent is 1:1:1; and the above-mentioned metal oxide is iron oxide.

[0124] All the above raw materials are added to a plow mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after dry mixing, water is added for wet mixing, wherein the water accounts for 46 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after wet mixing, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after kneading, the mud is practiced, and after the mud is practiced, it is put into an extruder to obtain a unit body by extrusion; the unit body is sequentially subjected to microwave drying, hole plugging, degreasing, anaerobic sintering, and oxidative sintering, and then is sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0125] Example 6

[0126] In this example, the proportion of silicon carbide powder is 80 wt.% with respect to the main material, wherein the proportion of the first silicon carbide powder is 25 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.25:1, the proportion of the second silicon carbide powder is 50 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.32:1, the proportion of the third silicon carbide powder is 5 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.19:1, the proportion of elemental silicon powder is 18.2 wt.%, the proportion of clay is 0.5 wt.%, the proportion of metal oxide powder is 1.3 wt.%, the proportion of binder is 6.8 wt.%, and the proportion of pore-forming agent is 13.5 wt.%; the above binder is polyethylene glycol; the above pore-forming agent is polyvinyl alcohol and polymethyl methacrylate microspheres, and the mass ratio of polyvinyl alcohol to polymethyl methacrylate microspheres in the pore-forming agent is 1:1; and the above metal oxide is aluminum oxide.

[0127] All the above raw materials are added to a plow mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after dry mixing, water is added for wet mixing, wherein the water accounts for 46 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after wet mixing, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after kneading, the mud is practiced, and after the mud is practiced, it is put into an extruder to obtain a unit body by extrusion; the unit body is sequentially subjected to microwave drying, hole plugging, degreasing, anaerobic sintering, and oxidative sintering, and then is sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0128] Example 7

[0129] In this embodiment, the proportion of silicon carbide powder in the main material is 80wt.%, wherein the proportion of the first silicon carbide powder is 15wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.23:1, the proportion of the second silicon carbide powder is 60wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.38:1, the proportion of the third silicon carbide powder is 5wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.13:1, the proportion of elemental silicon powder is 18wt.%, the proportion of clay is 0.5wt.%, the proportion of metal oxide powder is 1.5wt.%, the proportion of binder is 6.8wt.%, and the proportion of pore-forming agent is 17.6wt.%; the above-mentioned binder is ethyl cellulose; the above-mentioned pore-forming agent is polyvinyl alcohol and polymethyl methacrylate microspheres, and the mass ratio of polyvinyl alcohol to polymethyl methacrylate microspheres in the pore-forming agent is 1:1; and the above-mentioned metal oxide is calcium oxide.

[0130] All the above-mentioned raw materials are added into a plowshare mixer for dry mixing, wherein the dry mixing time is 15min and the dry mixing speed is 95rpm; after the dry mixing is completed, water is added for wet mixing, wherein the proportion of water in the main material is 46.5wt.%, the wet mixing time is 5min, and the wet mixing speed is 95rpm; after the wet mixing is completed, the obtained mixture is put into a double-shaft kneader for kneading, and the kneading time is 60min; after the kneading is completed, the dough is rolled, and after the rolling is completed, the dough is put into an extruder to obtain unit bodies by extrusion; the unit bodies are sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, oxidizing sintering, and then sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0131] Example 8

[0132] In this embodiment, the proportion of silicon carbide powder in the main material is 80wt.%, wherein the proportion of the first silicon carbide powder is 5wt.%, the mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is 0.25:1, the proportion of the second silicon carbide powder is 70wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.3:1, the proportion of the third silicon carbide powder is 5wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.25:1, the proportion of elemental silicon powder is 18wt.%, the proportion of clay is 0.5wt.%, the proportion of metal oxide powder is 1.5wt.%, the proportion of binder is 2wt.%, and the proportion of pore-forming agent is 22.7wt.%; the above-mentioned binder is ethyl cellulose; the above-mentioned pore-forming agent is polyacrylic acid, polyacrylamide, and starch, and the mass ratio of polyacrylic acid to polyacrylamide to starch in the pore-forming agent is 1:1:1; and the above-mentioned metal oxide is barium oxide.

[0133] All the above raw materials are added to a plow mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after the dry mixing is completed, water is added for wet mixing, wherein the water accounts for 46.8 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after the wet mixing is completed, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after the kneading is completed, the dough is rolled, and after the rolling is completed, the dough is put into an extruder to obtain unit bodies by extrusion; the unit bodies are sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then are sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0134] Example 9

[0135] In this example, the proportion of silicon carbide powder is 80 wt.% of the main material, the first silicon carbide powder is not contained, the proportion of the second silicon carbide powder is 75 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is 0.4:1, the proportion of the third silicon carbide powder is 5 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is 0.15:1, the proportion of elemental silicon powder is 17.8 wt.%, the proportion of clay is 0.5 wt.%, the proportion of metal oxide powder is 1.7 wt.%, the proportion of the binder is 2 wt.%, and the proportion of the pore-forming agent is 23.23 wt.%; the binder is methyl cellulose; the pore-forming agent is polyacrylic acid, starch, and polyacrylamide, and the mass ratio of polyacrylic acid, starch, and polyacrylamide in the pore-forming agent is 1:1:1; and the metal oxide is sodium oxide.

[0136] All the above raw materials are added to a plow mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after the dry mixing is completed, water is added for wet mixing, wherein the water accounts for 46.8 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after the wet mixing is completed, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after the kneading is completed, the dough is rolled, and after the rolling is completed, the dough is put into an extruder to obtain unit bodies by extrusion; the unit bodies are sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then are sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0137] Comparative Example 1

[0138] In the embodiment, the proportion of silicon carbide powder is 80 wt.%, the proportion of high-purity silicon carbide powder with a single particle size and a particle size of 30.3 μm is 80 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the high-purity silicon carbide powder is 0.05:1, the proportion of elemental silicon powder is 18 wt.%, the proportion of clay is 0.5 wt.%, the proportion of metal oxide powder is 1.5 wt.%, the proportion of binder is 6.8 wt.%, and the proportion of pore-forming agent is 3 wt.%; the binder is ethyl cellulose; the pore-forming agent is polyacrylic acid and starch, and the mass ratio of polyacrylic acid to starch in the pore-forming agent is 1:1; and the metal oxide is aluminum oxide.

[0139] All the above raw materials are added to a plow mixer for dry mixing, wherein the dry mixing time is 15 min, and the dry mixing speed is 95 rpm; after the dry mixing is completed, water is added for wet mixing, wherein the proportion of water to the main material is 45.2 wt.%, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after the wet mixing is completed, the obtained mixture is put into a double-shaft kneader for kneading, and the kneading time is 60 min; after the kneading is completed, the dough is rolled, and after the rolling is completed, the dough is put into an extruder to obtain a unit body; the unit body is sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidation sintering, and then is sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0140] Comparative Example 2

[0141] In the embodiment, the proportion of silicon carbide powder is 80 wt.%, the proportion of high-purity silicon carbide powder with a single particle size and a particle size of 30.1 μm is 80 wt.%, the mass ratio of 4H-SiC to 6H-SiC in the high-purity silicon carbide powder is 0.03:1, the proportion of elemental silicon powder is 18 wt.%, the proportion of clay is 0.5 wt.%, the proportion of metal oxide powder is 1.5 wt.%, the proportion of binder is 6.8 wt.%, and the proportion of pore-forming agent is 2.8 wt.%; the binder is carboxymethyl cellulose; the pore-forming agent is polyacrylic acid and starch, and the mass ratio of polyacrylic acid to starch in the pore-forming agent is 1:1; and the metal oxide is magnesium oxide.

[0142] The above-mentioned raw materials are added into a plough mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after the dry mixing, water is added for wet mixing, wherein the water accounts for 45.2 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after the wet mixing, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after the kneading, pugging is performed, and after the pugging, the obtained product is put into an extruder to obtain a unit body; the unit body is sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then is sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0143] Comparative Example 3

[0144] In this example, the proportion of silicon carbide powder in the main material is 80 wt.%, a single particle size of high-purity silicon carbide powder is used, the particle size of the high-purity silicon carbide powder is 30.5 μm, the mass ratio of 4H-SiC to 6H-SiC in the high-purity silicon carbide powder is 0.05:1, the proportion of elemental silicon powder is 18 wt.%, the proportion of clay is 0.5 wt.%, the proportion of metal oxide powder is 1.5 wt.%, the proportion of binder is 6.8 wt.%, and the proportion of pore-forming agent is 23 wt.%; the binder is glycerol; the pore-forming agent is polyacrylic acid, polyacrylamide, and starch, and the mass ratio of polyacrylic acid, polyacrylamide, and starch in the pore-forming agent is 1:1; the metal oxide is barium oxide

[0145] The above-mentioned raw materials are added into a plough mixer for dry mixing, wherein the dry mixing time is 15 min and the dry mixing speed is 95 rpm; after the dry mixing, water is added for wet mixing, wherein the water accounts for 45.2 wt.% of the main material, the wet mixing time is 5 min, and the wet mixing speed is 95 rpm; after the wet mixing, the obtained mixture is put into a double shaft kneader for kneading, and the kneading time is 60 min; after the kneading, pugging is performed, and after the pugging, the obtained product is put into an extruder to obtain a unit body; the unit body is sequentially subjected to microwave drying, hole blocking, degreasing, anaerobic sintering, and oxidative sintering, and then is sequentially subjected to splicing, skin grinding, and skin grafting to obtain a honeycomb ceramic carrier.

[0146] Comparative Examples 1 and 2 are different from Example 1 in that a single particle size of high-purity silicon carbide powder is used, and the mass ratio of 4H-SiC to 6H-SiC in the powder is less than 0.1:1. Comparative Example 3 is different from Example 9 in that a single particle size of high-purity silicon carbide powder is used, and the mass ratio of 4H-SiC to 6H-SiC in the powder is less than 0.1:1.

[0147] The particle size ratio of the silicon carbide powder in each of the above-mentioned examples and comparative examples is shown in Table 1 below.

[0148] Part of the formula of each example and comparative example in Table 1

[0149] The following Table 2 is the product performance of each example and comparative example. Each group of crystal phase is analyzed by XRD (X-ray diffraction analyzer), model JS / YQ XRD-201, scanning angle range 10°-80°, scanning speed 0.2s / step, scanning step 0.02° / step. The median pore size, average pore size, porosity, and pore volume are tested by mercury intrusion method, by making a unit into a sample block with length 10mm, width 10mm, and height 15mm, using a mercury intrusion instrument (MicroActive AutoPore V 9600 Version 2.03.00) of American Mac Enterprise. The test method is national standard GB / T21650.1-2008. The thermal diffusivity is tested by laser thermal conductivity instrument, by intercepting a sample piece with side length 10mm*10mm and thickness 1mm, using a laser thermal conductivity instrument (LFA 467) of German Nicer, under the condition of temperature interval 50k / min, and the test method is national standard GB / T 22588-2008.

[0150] The performance of honeycomb ceramic carrier of each example and comparative example in Table 2

[0151] It is worth noting that during the preparation process, 6H-SiC will be converted into SiO2 and CO2, at this time the content of 6H-SiC crystal phase will decrease, and the content of SiO2 will increase, resulting in an increase in the ratio of 4H-SiC to 6H-SiC.

[0152] Compared with examples 1-9, the special crystal phase ratio of SiC powder with lower cost is used to make the honeycomb ceramic carrier, wherein the thermal diffusivity, porosity, and pore volume of example 1 are similar to those of comparative examples 1 and 2, and the thermal diffusivity of examples 8 and 9 is higher than that of comparative example 3 under the condition of high porosity. The special crystal phase ratio of SiC powder with lower cost used in the present application is beneficial to preparing a honeycomb ceramic carrier with similar performance to high-purity SiC honeycomb ceramic and with special crystal phase ratio, wherein the crystal phase ratio of 4H to 6H is 0.25-0.5, without reducing the product performance, and the honeycomb ceramic carrier of the present application has higher thermal conductivity under the condition of high porosity.

[0153] Referring to Fig. 2, Fig. 2 is an XRD diagram of high-purity silicon carbide (1), silicon carbide primary powder (2), silicon carbide secondary powder (3), and silicon carbide tertiary powder (4) raw materials from top to bottom. As can be seen from the figure, the four SiC raw materials are composed of 4H-SiC and 6H-SiC crystal phases, of which six main peaks represent 6H-SiC crystal phase 2 main peaks represent 4H-SiC crystal phase (◆), 4H-SiC is a hexagonal silicon carbide with a stacking sequence of 4 layers of repeating units along the c-axis direction in the crystal structure, and the basic stacking sequence is ABAC...; 6H-SiC crystal form is a hexagonal silicon carbide with a stacking sequence of 6 layers of repeating units along the c-axis direction in the crystal structure, and the basic stacking sequence is ABCACB...; wherein each group of crystal phases is analyzed by an X-ray diffraction analyzer (XRD), the model number is JS / YQ XRD-201, the scanning angle range is 10°-80°, the scanning speed is 0.2s / step, and the scanning step is 0.02° / step; the semi-quantitative analysis method of XRD is GB_T 42676-2023.

[0154] It can be seen that the mass ratio of 4H-SiC to 6H-SiC in the high-purity silicon carbide powder raw material is 0.05, the mass ratio of 6H-SiC is more than 90%, and the peak value of 4H-SiC is significantly lower than that of the other three raw materials, and the elemental silicon powder accounts for 0.5% (the proportion is small and not marked in Fig. 2), the mass ratio of 4H-SiC to 6H-SiC in the primary silicon carbide powder is 0.19, and the elemental silicon powder accounts for 0.1%, the mass ratio of 4H-SiC to 6H-SiC in the secondary silicon carbide powder is 0.36, and the elemental silicon powder accounts for 0.2%, and the mass ratio of 4H-SiC to 6H-SiC in the tertiary silicon carbide powder is 0.19, and the elemental silicon powder accounts for 0.58%.

[0155] Referring to Fig. 3, Fig. 3 is an XRD diagram of the finished product carrier of Comparative Example 1 (5), Comparative Example 2 (6), Example 1 (7), Example 5 (8), and Example 8 (9) from top to bottom. As can be seen from the XRD pattern of each product, the finished product, i.e. the honeycomb ceramic carrier, obtained by the above-mentioned examples and comparative examples contains four crystal phases: 4H-SiC (◆) and The peak of 4H-SiC in the comparative example is obviously lower; the mass ratio of 4H-SiC to 6H-SiC in the comparative example 1 (10) is 0.072, the mass ratio of 4H-SiC to 6H-SiC in the comparative example 2 (11) is 0.067, the mass ratio of 4H-SiC to 6H-SiC in the example 1 (12) is 0.412, the mass ratio of 4H-SiC to 6H-SiC in the example 5 (13) is 0.279, and the mass ratio of 4H-SiC to 6H-SiC in the example 8 (14) is 0.395, it can be seen that the peak of 4H-SiC in the comparative example is obviously lower and even tends to be flat, and the peak of 6H-SiC is higher, while the peak of 4H-SiC in the example is higher, and the peak of 6H-SiC is lower compared with the comparative example.

[0156] The above is only a specific embodiment of the present application, but the protection scope of the present application is not limited to this, any skilled person in the art can easily think of changes or replacements within the technical range disclosed by the present application, which should be covered in the protection scope of the present application. Therefore, the protection scope of the present application should be subject to the protection scope of the claims. In addition, the principles and embodiments of the present application are described by applying specific examples in the specification, and the above example is only used to help understand the method and core idea of the present application, and the content of the specification should not be understood as a limitation of the present application.

Claims

1. A honeycomb ceramic substrate, characterized by, The honeycomb ceramic carrier contains silicon carbide, the crystal phase of the silicon carbide includes 4H-SiC and 6H-SiC, the mass of the 4H-SiC accounts for 13% to 30% of the total mass of the honeycomb ceramic carrier, the mass of the 6H-SiC accounts for 40% to 55% of the total mass of the honeycomb ceramic carrier, the porosity of the honeycomb ceramic carrier is 45% to 70%, preferably 50 to 65%.

2. The honeycomb ceramic carrier of claim 1, wherein, The mass ratio of the 4H-SiC to the 6H-SiC is 1:(2 to 4), preferably 1:

2.

3. The honeycomb ceramic carrier of claim 1 or 2, wherein, The honeycomb ceramic carrier further contains elemental silicon, the mass of the elemental silicon accounts for 10% to 25% of the total mass of the honeycomb ceramic carrier, preferably 15% to 25%; And / or, the honeycomb ceramic carrier further contains silicon dioxide, the mass of the silicon dioxide accounts for 5% to 25% of the total mass of the honeycomb ceramic carrier, preferably 8% to 18%.

4. The honeycomb ceramic substrate of any one of claims 1-3, wherein, The honeycomb ceramic carrier has a thermal diffusivity of 5 to 25 mm 2 / s, preferably 16 to 20 mm 2 / s.

5. The honeycomb ceramic substrate of any one of claims 1-4, wherein, The raw materials of the honeycomb ceramic carrier include main materials and auxiliary materials, wherein the main materials include two or three of the following: a first silicon carbide powder with a particle size of 30 to 50 μm, a second silicon carbide powder with a particle size of 15 to 30 μm, and a third silicon carbide powder with a particle size less than 15 μm; Preferably, the particle size of the first silicon carbide powder is 35 to 45 μm, the particle size of the second silicon carbide powder is 20 to 30 μm, and the particle size of the third silicon carbide powder is 4 to 12 μm.

6. The honeycomb ceramic substrate of any one of claims 1-5, wherein, The mass ratio of the 4H-SiC to the 6H-SiC in the first silicon carbide powder is (0.15 to 0.25):1, preferably (0.17 to 0.23):1; And / or, the mass ratio of the 4H-SiC to the 6H-SiC in the second silicon carbide powder is (0.3 to 0.4):1, preferably (0.3 to 0.35):1; And / or, the mass ratio of the 4H-SiC to the 6H-SiC in the third silicon carbide powder is (0.15 to 0.25):1, preferably (0.15 to 0.2):

1.

7. The honeycomb ceramic substrate of any one of claims 1-6, wherein, The main materials further include an elemental silicon powder, a metal oxide, clay, and / or the auxiliary materials include a binder and a pore-forming agent; Preferably, the mass of the silicon carbide powder accounts for 60% to 90% of the mass of the main materials, more preferably 75% to 85%, the mass of the elemental silicon powder accounts for 15% to 25% of the mass of the main materials, more preferably 15% to 20%, the mass of the metal oxide accounts for 0.1% to 2.5% of the mass of the main materials, more preferably 0.5% to 2%, the mass of the clay accounts for 0.1% to 2% of the mass of the main materials, more preferably 0.5% to 1.5%, the mass of the binder accounts for 4% to 10% of the mass of the main materials, more preferably 5% to 8%, and the mass of the pore-forming agent accounts for 2% to 30% of the mass of the main materials, more preferably 5% to 15%.

8. The honeycomb ceramic substrate of any one of claims 1-7, wherein, The pore-forming agent is selected from at least one of polyacrylic acid, polyacrylamide, polyvinyl alcohol, polymethyl methacrylate microspheres, starch, and expanded microspheres; And / or, the D10 of the pore-forming agent is greater than or equal to 10 μm and the D90 is less than or equal to 35 μm.

9. The honeycomb ceramic substrate of any one of claims 1-8, wherein, The particle size specification of the elemental silicon powder is D10>1 μm and D90<15 μm, the particle size specification of the metal oxide is D10>2.8 μm and D90<8 μm, and the particle size specification of the clay is D10>2 μm and D90<17 μm; And / or, the binder is selected from at least one of polyvinyl alcohol, polyethylene glycol, carboxymethyl cellulose, methyl cellulose, and ethyl cellulose; And / or, the metal oxide is at least one selected from calcium oxide, sodium oxide, magnesium oxide, aluminum oxide, barium oxide, iron oxide, and copper oxide.

10. The honeycomb ceramic substrate of any one of claims 1-9, wherein, The mass of the first silicon carbide powder accounts for 0% to 50% of the mass of the main material, more preferably 4% to 40%, the mass of the second silicon carbide powder accounts for 30% to 75% of the mass of the main material, more preferably 30% to 40%, and the mass of the third silicon carbide powder accounts for 0% to 5% of the mass of the main material, more preferably 1% to 4%. Alternatively, the mass ratio of the first, second, and third silicon carbide powders is (0-50):(30-75):(0-5), and the mass of the first and third silicon carbide powders is not zero at the same time.

11. The honeycomb ceramic substrate of any one of claims 1-10, wherein, The honeycomb ceramic carrier has a pore density of 200-400 cpsi, preferably 275-305 cpsi.

12. The honeycomb ceramic substrate of any one of claims 1-11, wherein, The honeycomb ceramic carrier has a median pore size D50 of 10-30 μm, preferably 10-18 μm.

13. The honeycomb ceramic substrate of any one of claims 1-12, wherein, The honeycomb ceramic carrier has a pore volume of 0.18-0.6 mL / g, preferably 0.2-0.3 mL / g.

14. A method for producing a honeycomb ceramic carrier according to any one of claims 1 to 13, characterized in that, The method comprises the following steps: S1, providing raw materials, the raw materials comprising silicon carbide powder, elemental silicon powder, metal oxide, clay, binder, and pore-forming agent; S2, mixing, kneading, pugging, extrusion molding, drying, cutting, and sintering the raw materials in step S1 to obtain a ceramic monolith; S3, obtaining the honeycomb ceramic carrier by sequentially carrying out splicing, skinning, and skin grafting on the ceramic monolith.

15. The method of claim 14, wherein, The silicon carbide powder comprises two or three of the following: first silicon carbide powder with a particle size of 30-50 μm, second silicon carbide powder with a particle size of 15-30 μm, and third silicon carbide powder with a particle size of less than 15 μm; Preferably, the particle size of the first silicon carbide powder is 35-45 μm, the particle size of the second silicon carbide powder is 20-30 μm, and the particle size of the third silicon carbide powder is 4-12 μm.

16. The method according to claim 14 or 15, characterized in that The mass ratio of 4H-SiC to 6H-SiC in the first silicon carbide powder is (0.15-0.25):1, preferably (0.17-0.23):1; And / or, the mass ratio of 4H-SiC to 6H-SiC in the second silicon carbide powder is (0.3-0.4):1, preferably (0.3-0.35):1; And / or, the mass ratio of 4H-SiC to 6H-SiC in the third silicon carbide powder is (0.15-0.25):1, preferably (0.15-0.2):

1.

17. The method according to any one of claims 14 to 16, characterized in that, In step S2, there is also a pore blocking step between sintering and drying.

18. The method according to any one of claims 14 to 17, characterized in that, In step S2, the raw materials are mixed by using a mixing method of dry mixing first and then wet mixing. And / or, in the step S2, the drying is performed by using a microwave drying method. And / or, in the step S2, the sintering is performed by using a method of first oxygen-free sintering and then oxygen sintering.

19. An exhaust gas catalytic core body, characterized by The tail gas catalytic core comprises: The honeycomb ceramic carrier according to any one of claims 1 to 13 or the honeycomb ceramic carrier prepared by the method according to any one of claims 14 to 18; and A catalyst is coated on the inner wall surface of the pore of the honeycomb ceramic carrier.

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