CN112209719B

CN112209719B - Silicon carbide ceramic membrane and preparation method and application thereof

Info

Publication number: CN112209719B
Application number: CN202010978809.7A
Authority: CN
Inventors: 张久美; 程之强; 赵世凯; 薛友祥; 宋涛; 王重海; 唐钰栋; 王响; 徐丹丹; 马天双
Original assignee: Shandong Industrial Ceramics Research and Design Institute Co Ltd
Current assignee: Shandong Industrial Ceramics Research and Design Institute Co Ltd
Priority date: 2020-09-17
Filing date: 2020-09-17
Publication date: 2022-11-25
Anticipated expiration: 2040-09-17
Also published as: CN112209719A

Abstract

The invention discloses a silicon carbide ceramic membrane and a preparation method and application thereof, wherein the silicon carbide ceramic membrane comprises a support body and a membrane layer connected with the support body; the support body comprises the following raw materials in parts by weight: 85-92 parts of silicon carbide; 6-10 parts of a pore-forming agent; 8-15 parts of sintering binder; 3-8 parts of a forming assistant; the film layer comprises the following raw materials in parts by weight: 70-90 parts of corundum sand, 10-30 parts of sintering bonding agent, 10-20 parts of pore-forming agent, 38-50 parts of water, 0-0.3 part of dispersing agent and 0-0.3 part of suspending agent; wherein: the sintering bonding agent comprises, by weight, 76-96 parts of Chacun soil, 5-16 parts of dolomite and 3-16 parts of glass fiber powder. The firing temperature of the support body is reduced by changing a formula system of the support, and the firing temperature of the support body and the firing temperature of the film layer are controlled in the same temperature range, so that the one-time firing of the film layer and the support body is realized, and the original two-time firing of the support body and the film layer is replaced.

Description

Silicon carbide ceramic membrane and preparation method and application thereof

Technical Field

The invention relates to the technical field of high-temperature dust removal, in particular to a silicon carbide ceramic membrane and a preparation method and application thereof.

Background

The high-temperature dust removal technology is an international problem, high-efficiency and practical high-temperature dust removal equipment is still blank at home and abroad, and cyclone dust removal, high-temperature electric dust removal, particle layer transition dust removal, rigid ceramic filtration dust removal and other fiber filter materials are applied at present. The rigid ceramic filter has the characteristics of high temperature resistance, high dust removal efficiency, high strength, corrosion resistance, easy cleaning and regeneration and the like, and is widely applied to industries such as building materials, waste incineration and the like.

The silicon carbide ceramic membrane material is one of rigid ceramic filter materials, and in the preparation process of the existing silicon carbide ceramic membrane material, because the firing temperatures of a support body and a membrane layer are different, the firing temperature of the support body is 1370-1400 ℃, the firing temperature of the membrane layer is 1250-1270 ℃, the membrane layer is generally coated on the support body which is fired in advance and then fired again, and the secondary firing not only causes energy waste, but also easily causes the problems of cracking and falling off of the membrane layer because the membrane layer is not matched with the support body.

Disclosure of Invention

In order to solve the technical problems, the invention aims to provide a silicon carbide ceramic membrane and a preparation method and application thereof.

According to one aspect of the present invention, there is provided a silicon carbide ceramic film comprising a support and a film layer connected to the support;

the support body comprises the following raw materials in parts by weight: 85-92 parts of silicon carbide; 6-10 parts of a pore-forming agent; 8-15 parts of a sintering bonding agent; 3-8 parts of a forming assistant;

the film layer comprises the following raw materials in parts by weight: 70-90 parts of corundum sand, 10-30 parts of sintering bonding agent, 10-20 parts of pore-forming agent, 38-50 parts of water, 0-0.3 part of dispersing agent and 0-0.3 part of suspending agent;

wherein: the sintering bonding agent comprises, by weight, 76-96 parts of Chacun soil, 5-16 parts of dolomite and 3-16 parts of glass fiber powder.

Furthermore, the support body and the film layer are sintered at one time and are provided with a plurality of through holes, the aperture of each through hole is 30-33 mu m, and the pressure difference between two sides of each through hole is 300-400 pa when the wind speed is 1 m/min.

Furthermore, the forming auxiliary agent is thermosetting phenolic resin.

Further, the pore-forming agent is activated carbon or walnut shell powder.

According to another aspect of the present invention, there is provided a method for producing a silicon carbide ceramic film, comprising the steps of:

preparing a support body: mixing silicon carbide, a pore-forming agent, a sintering bonding agent and a forming auxiliary agent to obtain a first mixture, adding the first mixture into a mold, and carrying out isostatic pressing under the pressure of 40-15 OMPa: demoulding to obtain a blank after forming;

drying: drying the blank at 60-80 ℃ for 8-12 hours;

preparing a film layer: mixing corundum sand, a sintering bonding agent, a pore-forming agent, water, a dispersant part and a suspending agent part to obtain a mixture II,

film spraying: spraying the mixture II on the surface of the blank;

and (3) heat treatment: the highest temperature of the heat treatment is controlled to be 1230-1280 ℃, and the heat preservation time of the highest temperature is 2-5 hours.

Further, the heat treatment comprises:

the first stage is as follows: heating to 180-220 ℃ according to 0.5-1 min/DEG C;

and a second stage: heating to 500-700 ℃ at the temperature of 2-3 min/DEG C;

and a third stage: heating to the highest temperature at 1.5-3 min/DEG C, wherein the holding time of the highest temperature is 2-5 hours.

According to another aspect of the present invention, there is provided a use of any one of the silicon carbide ceramic membranes described above for high temperature dust removal.

Compared with the prior art, the invention has the beneficial effects that:

1. according to the method, the firing temperature of the support body is reduced by changing a formula system of the support, the firing temperature of the support body and the firing temperature of the film layer are controlled in the same temperature interval, the film layer and the support body are fired at one time, and the original support body and the original film layer are replaced by twice firing.

2. Compared with the existing two-time sintering process, the one-time sintering process has the advantages that the process flow is shortened, the one-time sintering (heat treatment) is reduced, the problem of repeated transportation of the support body is avoided, and the energy is saved.

3. Compared with the traditional process which adopts secondary firing, silicon carbide is easy to oxidize, the surface of the support body has melting problems due to the oxidation of the silicon carbide in the original 1370-1400 ℃ firing process, the phenomena of surface blistering, pot holes, sand sticking and the like are caused, the quality of the film layer is influenced, the melting part is airtight, and the air permeability resistance of the final product is larger. On the other hand, after the surface of the blank body is coated with the film, the silicon carbide on the surface of the blank body can be isolated from the air, so that the problem of sintering and oxidation of the silicon carbide is avoided.

Drawings

FIG. 1 is a graph showing the strength comparison between the membrane tube obtained in example 4 and the membrane tube obtained in the two-firing process.

Detailed Description

In order to better understand the technical scheme of the invention, the invention is further explained by combining the drawings and the specific embodiments in the specification.

Example 1:

a silicon carbide ceramic membrane comprises a support body and a membrane layer connected with the support body;

the support body comprises the following raw materials in parts by weight: 85 parts of silicon carbide; 6 parts of a pore-forming agent; 8 parts of a sintering bonding agent; 3 parts of a forming auxiliary agent; the pore-forming agent is activated carbon or walnut shell powder; the forming auxiliary agent is thermosetting phenolic resin.

The film layer comprises the following raw materials in parts by weight: 70 parts of corundum sand, 10 parts of sintering bonding agent, 10 parts of pore-forming agent, 38 parts of water, 0.1 part of dispersing agent and 0.1 part of suspending agent;

wherein: the sintering bonding agent comprises, by weight, 76 parts of Chacun soil, 5 parts of dolomite and 3 parts of glass fiber powder.

The support body and the film layer are sintered at one time and are provided with a plurality of through holes, the aperture of each through hole is 30-33 mu m, the pressure difference between two sides of each through hole is 300-400 pa when the wind speed is 1m/min, and the silicon carbide ceramic film can be applied to the field of high-temperature dust removal.

Example 2:

the support body comprises the following raw materials in parts by weight: 92 parts of silicon carbide; 10 parts of pore-forming agent; 15 parts of sintering bonding agent; 8 parts of a forming auxiliary agent; the pore-forming agent is activated carbon or walnut shell powder; the forming auxiliary agent is thermosetting phenolic resin.

The film layer comprises the following raw materials in parts by weight: 90 parts of corundum sand, 30 parts of sintering bonding agent, 20 parts of pore-forming agent, 50 parts of water, 0.3 part of dispersing agent and 0.3 part of suspending agent;

wherein: the sintering bonding agent comprises 96 parts of kaolin, 16 parts of dolomite and 16 parts of glass fiber powder in parts by weight.

Silicon carbide is selected as aggregate of the support body, and a sintering binding agent is added, so that the support body has better high-temperature stability and lower thermal expansion coefficient, the sintering temperature of the support body is 1230-1280 ℃, and the sintering temperature of the support body and the sintering temperature of the film layer are controlled in the same temperature range, so that the one-time sintering of the support body and the film layer is realized.

The support body and the film layer are sintered at one time and are provided with a plurality of through holes, the aperture of each through hole is 30-33 mu m, and the pressure difference between two sides of each through hole is 300-400 pa when the wind speed is 1 m/min.

Example 3:

the support comprises the following raw materials in parts by weight: 90 parts of silicon carbide; 8 parts of a pore-forming agent; 12 parts of a sintering bonding agent; 5 parts of a forming auxiliary agent; the pore-forming agent is activated carbon or walnut shell powder; the forming auxiliary agent is thermosetting phenolic resin.

The film layer comprises the following raw materials in parts by weight: 80 parts of corundum sand, 20 parts of sintering bonding agent, 15 parts of pore-forming agent, 42 parts of water, 0.2 part of dispersing agent and 0.2 part of suspending agent;

wherein: the sintering bonding agent comprises 86 parts of Zhangcun soil, 8 parts of dolomite and 6 parts of glass fiber powder in parts by weight.

Example 4:

a preparation method of a silicon carbide ceramic membrane comprises the following steps:

step 1, support body preparation: mixing silicon carbide, a pore-forming agent, a sintering bonding agent and a forming auxiliary agent to obtain a first mixture, and then sieving the first mixture by a 12-mesh sieve; after sieving, adding the mixture I into a mold, carrying out isostatic pressing under the pressure of 40MPa, and demolding to obtain a blank; the forming auxiliary agent can improve the strength of a formed blank body and can also generate chemical reaction in the drying process to improve the strength of the blank body; the isostatic compaction is adopted, the density is uniform, the strength is higher, the regularity is good, the blank is easy to dry and not to deform, the process is simple, the mechanical operation is realized, the production efficiency is high, and the large-scale production is easy to realize.

Step 2, drying: drying the blank at 60 ℃ for 8 hours; experiments prove that the strength of the green body in the primary sintering process can be lost by more than 95% after meeting water, the strength loss of the formed green body after meeting water can be reduced after the formed green body is dried, the strength loss is controlled to be less than 20%, and the requirements of transferring, film spraying and kiln loading can be met;

step 3, preparing a film layer: mixing corundum sand, a sintering bonding agent, a pore-forming agent, water, a dispersant part and a suspending agent part to obtain a mixture II,

step 4, spraying a film: spraying the mixture II on the surface of the blank;

step 5, heat treatment and sintering: heating to 180 deg.C at 0.5 min/deg.C to remove water; then heating to 500 ℃ at the temperature of 2 min/DEG C to carbonize and remove organic matters such as pore-forming agent; then the temperature is raised to 1230 ℃ at 1.5 min/DEG C, so that the binding agent is subjected to phase reaction in the high-temperature process; the highest sintering temperature is controlled to be 1230-1280 ℃, and the heat preservation time is 5 hours, so that the phase reaction is fully carried out, and the silicon carbide ceramic membrane is prepared. By optimizing the firing system, residual pore-forming agent in the support is oxidized and discharged at a high temperature of 1230-1280 ℃, the performance of the membrane tube obtained by the one-firing process and the membrane tube obtained by the two-firing process are compared as shown in figure 1 and table 1, the strength difference of the support membrane tube obtained by the two-firing process is small, thermal shock resistance tests are carried out under the same conditions, no crack is generated, and the strength loss is below 20%. The air permeability resistance, porosity and aperture of the membrane tube are all kept at the same level under the condition of the same aggregate and the same membrane layer, which shows that the one-time sintering process has little influence on the performance of the product.

Table 1: the performance of the membrane tube obtained by the primary sintering process is compared with that of the membrane tube obtained by the secondary sintering process

Example 5:

step 1, support body preparation: mixing silicon carbide, a pore-forming agent, a sintering bonding agent and a forming auxiliary agent to obtain a first mixture, sieving the first mixture by a 12-mesh sieve, adding the first mixture into a mold, carrying out isostatic pressing under the pressure of 15OMPa, and demolding to obtain a blank body after molding; the forming auxiliary agent can improve the strength of a formed blank body and can also generate chemical reaction in the drying process to improve the strength of the blank body; the isostatic compaction is adopted, the density is uniform, the strength is higher, the regularity is good, the blank is easy to dry and not to deform, the process is simple, the mechanical operation is realized, the production efficiency is high, and the large-scale production is easy to realize.

Step 2, drying: drying the blank at 80 ℃ for 12 hours; experiments prove that the strength of the green body in the primary sintering process can be lost by more than 95% after meeting water, the strength loss of the formed green body after meeting water can be reduced after the formed green body is dried, the strength loss is controlled to be less than 20%, and the requirements of transferring, film spraying and kiln loading can be met;

step 4, spraying a film: spraying the mixture II on the surface of the blank;

step 5, heat treatment and sintering: heating to 220 deg.C at 1 min/deg.C to remove water; then heating to 700 ℃ at 3 min/DEG C to carbonize and remove organic matters such as pore-forming agent; then heating to the highest temperature at 3 min/DEG C to enable the bonding agent to generate phase reaction in the high-temperature process; the highest firing temperature is controlled at 1250 ℃, and the heat preservation time is 4 hours, so that the phase reaction is fully carried out, and the silicon carbide ceramic membrane is prepared.

Example 6:

step 1, support body preparation: mixing silicon carbide, a pore-forming agent, a sintering bonding agent and a forming auxiliary agent to obtain a first mixture, sieving the first mixture by a 12-mesh sieve, adding the first mixture into a mold, carrying out isostatic pressing under the pressure of 100MPa, and demolding to obtain a blank body after molding; the forming auxiliary agent can improve the strength of a formed blank body and can also generate chemical reaction in the drying process to improve the strength of the blank body; the method has the advantages of uniform density, high strength, good regularity, easy drying of the blank, no deformation, simple process, mechanical operation, high production efficiency and easy large-scale production.

Step 2, drying: drying the blank at 70 ℃ for 10 hours; experiments prove that the strength of the green body in the one-time sintering process can be lost by more than 95% after meeting water, the strength loss after meeting water can be reduced after the formed green body is dried, the strength loss is controlled to be less than 20%, and the requirements of transferring, film spraying and kiln loading can be met;

step 4, spraying a film: spraying the mixture II on the surface of the blank;

step 5, heat treatment and sintering: heating to 200 deg.C at 0.8 min/deg.C to remove water from the binder; then heating to 600 ℃ at the speed of 2.5 min/DEG C to carbonize and remove organic matters such as pore-forming agent; then heating to the highest temperature at 2 min/DEG C to enable the bonding agent to generate phase reaction in the high-temperature process; the highest firing temperature is controlled to be 1280 ℃, the heat preservation time is 3 hours, and the phase reaction is fully carried out to prepare the silicon carbide ceramic membrane.

The above description is only a preferred embodiment of the application and is illustrative of the principles of the technology employed. It will be appreciated by a person skilled in the art that the scope of the invention as referred to in the present application is not limited to the embodiments with a specific combination of the above-mentioned features, but also covers other embodiments with any combination of the above-mentioned features or their equivalents without departing from the inventive concept. For example, the above features may be replaced with (but not limited to) features having similar functions disclosed in the present application.

Claims

1. The ceramic film is characterized by consisting of a support and a film layer connected with the support;

the support body comprises the following raw materials in parts by weight: 85 to 92 parts of silicon carbide; 6 to 10 parts of a pore-forming agent; 8-15 parts of a sintering binding agent; 3-8 parts of a forming aid, wherein the forming aid is thermosetting phenolic resin;

the film layer comprises the following raw materials in parts by weight: 70-90 parts of corundum sand, 10-30 parts of fired bonding agent, 10-20 parts of pore forming agent, 38-50 parts of water, 0-0.3 part of dispersing agent and 0-0.3 part of suspending agent;

the support body and the film layer are sintered at one time and provided with a plurality of through holes, the aperture of each through hole is 30-33 mu m, and the pressure difference between two sides of each through hole is 300-400 Pa when the wind speed is 1m/min, wherein the sintered bonding agent comprises, by weight, 76-96 parts of kamura soil, 5-16 parts of dolomite and 3-16 parts of glass fiber powder;

controlling the highest temperature of heat treatment at 1230 to 1280 ℃ during firing, and keeping the temperature of the highest temperature for 2 to 5 hours, wherein the heat treatment comprises the following steps:

the first stage is as follows: heating to 180-220 ℃ according to 0.5-1min/° C;

and a second stage: heating to 500 to 700 ℃ at a temperature of 2 to 3 min/DEG C;

2. The silicon carbide ceramic membrane according to claim 1, wherein the pore-forming agent is activated carbon or walnut shell powder.

3. A method for producing a silicon carbide ceramic film according to any one of claims 1 to 2, comprising the steps of:

preparing a support body: mixing silicon carbide, a pore-forming agent, a sintering bonding agent and a forming auxiliary agent to obtain a first mixture, adding the first mixture into a mold, carrying out isostatic pressing at a pressure of 40-150 MPa, and demolding to obtain a blank body after molding;

drying: drying the blank at 60 to 80 ℃ for 8 to 12 hours;

preparing a film layer: mixing corundum sand, a sintering bonding agent, a pore-forming agent, water, a dispersing agent and a suspending agent to obtain a mixture II;

film spraying: spraying the mixture II on the surface of the blank;

and (3) heat treatment: the highest temperature of the heat treatment is controlled to be 1230 to 1280 ℃, and the heat preservation time of the highest temperature is 2 to 5 hours.

4. Use of a silicon carbide ceramic membrane according to any one of claims 1 to 2 for high temperature dedusting.