CN1277173A

CN1277173A - Honeycomb ceramic as one kind of high-performance composite material

Info

Publication number: CN1277173A
Application number: CN 00113540
Authority: CN
Inventors: 胡勇波; 黄睦松; 黄睦潮
Original assignee: Individual
Current assignee: Individual
Priority date: 2000-07-13
Filing date: 2000-07-13
Publication date: 2000-12-20
Anticipated expiration: 2020-07-13
Also published as: CN1156412C

Abstract

Honeycomb ceramic has a material composition of cordierite 50-80wt%, aluminum titanate 10-30wt%,ZrSiO3+ZrO2 5-20wt%, and Y2O3 0.1-1wt% and is prepared through the processes of preparing homogeneous 1-10 micron devitrified material, extruding honeycomb body and composite solid phase reaction at 1300-1500 sintering temperature. It has low thermal expansion coefficient, high heat stability, high compressive structure, thin porous wall, high porosity and high absorption to catalyst, so that it is especially suitable for use as catalyst for vehicle tail gas purifying catalyst.

Description

High-performance composite material honeycomb ceramic

The invention belongs to the technical field of ceramics, and relates to a high-performance composite material honeycomb ceramic.

At present, due to the rapid development of cities and the improvement of living standards of people, the number of automobiles in the cities is increasing day by day, the pollution of tail gas discharged by the automobiles to urban environment is more and more serious, the purification of the tail gas is an important measure for reducing the pollution of the tail gas of the automobiles to the cities, and more cities adopt mandatory measures to require that tail gas purification devices are installed in exhaust devices of the automobiles. However, the existing purification catalyst carrier for the purification device is not ideal, so that the exhaust purification is difficult to achieve the expected effect of people, and the problem of exhaust purification is a difficult problem which needs to be solved urgently by finding a purification catalyst carrier which is easy to produce, heat-resistant, shock-resistant and good in adsorptivity. The honeycomb ceramics are being developed as carriers of catalysts for purifying industrial exhaust gas and automobile exhaust gas and ceramic heat exchangers for recovering heat energy because of their characteristics of easy molding, high porosity, heat resistance and strong adsorptivity. Chinese patent publication No. CN1033455A (published: 21/6/1989) discloses a "cordierite honeycomb ceramic". It is made up by using 45-55% of clay, 30-49% of talcum, 10-15% of alumina and adhesive through a certain preparation process. Although the honeycomb ceramic has good matching performance and better water absorption with noble metal catalysts and rare earth metal catalysts. However, the porcelain has low compressive strength, thicker hole wall and larger thermal expansion coefficient, and cannot be used as a catalyst carrier for purifying automobile exhaust, because the catalyst carrier in the automobile exhaust purifying device must be suitable for the working condition in the purifying device, and the carrier is required to have larger compressive strength, heat resistance and very small thermal expansion coefficient to adapt to the rapid change of temperature when an automobile runs and jolts.

The invention aims to provide a high-performance composite material honeycomb ceramic which is used as a purification catalyst carrier of an automobile exhaust purification device and a catalyst carrier for purifying industrial waste gas, and has the advantages of low expansion coefficient, high temperature resistance, high strength, high water absorption, thin pore wall and high pore density.

The object of the present invention is achieved in the following manner. The high-performance composite material honeycomb ceramic is prepared from 50-80% of cordierite, 10-30% of aluminum titanate and 5-20% of ZrSiO₃+ZrO₂0.1-1% of Y₂O₃0-4% of Fe₂O₃The (weight percentage) is uniformly distributed in 1-10um microcrystals and extrudedThe pressed honeycomb body is obtained by solid-phase reaction compounding at the sintering temperature of 1300-1400 ℃. In the microstructure, cordierite wraps aluminum titanate, and aluminum titanate and ZrSiO simultaneously₃、ZrO₂、Y₂O₃Dispersed and distributed in the cordierite crystal phase. The used cordierite is composed of raw material and clinker, the clinker is produced by sol and gel method, the high purity cordierite clinker can be obtained, the method is:the cordierite is produced by the reaction of industrial pure 99.8% organosilicon with 99.9% aluminium nitrate and magnesium nitrate, besides clinker, it also uses partial raw material, and because the straight-wall honeycomb ceramic is made by hydraulic extrusion, it requires that the forming material has good plasticity, binding property, and very small drying shrinkage (drying shrinkage and firing shrinkage) of drying strength, so it requires that the raw material has complete clay water system technological properties, and at the same time, it also requires high-purity chemical components of used mineral raw material, mainly contains no alkali metal and alkaline earth metal oxide, otherwise the cordierite material synthesized by the raw material in the course of high-temp. reaction contains glass phase, and its thermal expansion coefficient (α) is large.

The cordierite raw material comprises the following components: high-purity raw talc, the composition of which requires: SiO 2₂60-62％、MgO 30-31％、CaO+K₂O+Na₂O is less than 0.2 percent (weight percentage), and the kaolin has the following composition requirements: SiO 2₂45-46％、Al₂O₃37-38％、Fe₂O₃0.2-0.8％、CaO+K₂O+Na₂O＜0.2％、

α-Al₂O₃The required content is 99.9% (-low alkali α -Al₂O₃)

The three components are prepared according to the pure theoretical standard components of cordierite.

The aluminum titanate is prepared according to the theoretical standard of the aluminum titanate, a mineralizer and a stabilizer are introduced to ensure that the aluminum titanate low-expansion material with stable structure can be synthesized at 1350-1400 ℃, and the mineralizer is Mg₂The inhibitor (stabilizer) is MgO. Aluminum titanate can also be synthesized by another method, namely:

ZrSiO used₃Is 1-5um fine particles, ZrO used₂Is 1-5um micropowder, preferably 1-2um micropowder.

The manufacturing method of the high-performance composite honeycomb ceramic comprises the following steps:

cordierite, aluminum titanate and ZrSiO prepared by synthetic reaction₂、ZrO₂Yttrium oxide (Y)₂O₃)、Fe₂O₃All become clinker, the calcining temperature is 1300-1400 ℃, the raw materials are mixed, ball milled and crushed to 350 meshes (the fineness is 0.5-5um), the raw material of cordierite is prepared by mixing high-purity raw talc, kaolin, α -Al₂O₃The three materials are mixed according to the pure theory of cordierite, ball milled and sieved with 300 meshes (fineness 5-10um), put into a polygonal pool water which is larger than hexagon (including hexagon), mixed with clinker powder according to the proportion of clinker to raw material (70-80) to (30-20), stirred for 2-4 hours, uniformly and filter-pressed and dehydrated into a mud cake, the water content of the mud cake is 24-28%, the mud cake is put into a rotting room for half a month, the temperature is controlled at 20-25 ℃, the humidity is 70-90%, and the dark room is sealed. Proportionally mixing with plasticizer (plasticizer)0.1-0.5% of CMC, 1-5% of glycerol, 0.1-0.5% of bonding agent MC, polyvinyl alcohol and composite phosphate ester, and pore-increasing agent: starch, dextrin and flour 1-10 wt%, vacuum pugging for 2-4 times, ageing for 24 hr, adding lubricant (such as water soluble mutton tallow, tung oil, PEG-400 type) 2-10 wt%, vacuum pugging, extrusion molding, drying, baking at 1300-1400 deg.C for 2-4 hr, and oxidizing flame baking.

The high-performance composite material honeycomb ceramic can achieve the following technical properties:

1. low coefficient of expansion: -1.0-1.8X 10^-6℃^-1

2. Compressive strength: 32.5-120MPa

3. Water absorption: 20 to 30 percent

4. The wall thickness of the hole (the wall thickness of the straight wall) is 0.18-0.35mm

5. Thermal stability: (800-1200 ℃) and (20-30 ℃) is qualified. Air cooling at 100 ℃ under 800 ℃ and safe.

6. Pore density: 400-.

The invention is mainly used for the aspects of automobile exhaust purification, industrial waste gas purification and the like.

The following are non-limiting examples of the invention:

example 1:

preparation of high-purity fine cordierite: the high-purity cordierite clinker is produced by a sol-gel method, namely, the high-purity cordierite is directly prepared by the reaction of industrial pure 99.8 percent of organic silicon, aluminum nitrate (with the purity of 99.9 percent) and magnesium nitrate.

Preparation of aluminum titanate: proportioning according to the theoretical composition of aluminium titanate, and adopting TiO₂And Al₂O₃As raw material, MgF is introduced₂Used as an inhibitor to synthesize the aluminum titanate low-thermal expansion material with stable structure at the temperature of 1350-1400 ℃.

50 parts (by weight, the same applies hereinafter) of cordierite and 1-5 parts of aluminum titanate₃Fine powder and ZrO₂10 parts of micro powder and Y₂O₃0.5 part of Fe₂O₃2 portions, calcining at 1300-1400 ℃ to prepare clinker, ball milling and crushing the prepared clinker, sieving with a 400-mesh sieve, and obtaining high-purity raw talc, kaolin, α -Al₂O₃Preparing cordierite raw material according to the pure theory of cordierite, taking 22.5 parts of cordierite raw material, ball-milling, crushing, sieving with a 300-mesh sieve,putting the prepared clinker and raw material (the proportion of the raw material to the clinker is 22.5: 77.5) into 8-edge pool water, stirring for 3 hours to be uniform, performing filter pressing dehydration to obtain a mud cake, keeping the water content of the mud cake at 24-28%, putting the mud cake in an ageing chamber for ageing for 15 days, keeping the ageing chamber in a dark chamber, sealing, controlling the temperature at 20-25 ℃, keeping the humidity at 70-90%, adding 0.5 part of CMC and 3 parts of glycerol as plasticizers after ageing, adding 0.1 part of MC, 0.2 part of polyvinyl alcohol and 0.2 part of composite phosphate as bonding agents, adding 2 parts of starch, 5 parts of dextrin and 3 parts of flour as pore-increasing agents, performing vacuum pugging for 3 times, putting the aged pugging material in the ageing chamber for ageing for 24 hours, adding 3 parts of mutton tallow and 5 parts of tung oil as lubricants into the aged pugging material, performing vacuum extrusion forming by adopting hydraulic pressure to obtain straight-wall puggingAnd (3) drying the formed honeycomb blank, sintering the dried honeycomb blank by oxidizing flame at the temperature of 1300-1400 ℃, and preserving the heat for 2 hours to obtain the high-performance composite material honeycomb ceramic. The manufactured samples passed the actual safe operation of 10 kilometres of Santana cars, all meeting the specified requirements.

The high-performance composite material honeycomb ceramic prepared by the invention has the advantages of low thermal expansion coefficient, good thermal stability, high compressive strength, thin pore wall, high pore density and good adsorption to a catalyst, is most suitable for being used as a carrier of an automobile exhaust purification catalyst, can adapt to the operating condition of an automobile, resists thermal vibration, high temperature and high strength, thereby ensuring good purification effect on the exhaust, being not easy to damage, having long service life and reducing the use cost.

Claims

1. The high-performance composite material honeycomb ceramic is characterized by comprising 50-80% of cordierite, 10-30% of aluminum titanate and 5-20% of ZrSiO₃+ZrO₂0.1-1% of Y₂O₃(weight percentage) is uniformly distributed by 1-10um microcrystals, and the honeycomb body formed by extrusion molding is obtained by solid phase reaction compounding at the sintering temperature of 1300-1400 ℃.

2. The high performance composite honeycomb ceramic of claim 1, wherein the crystalline material further comprises 0-4% Fe₂O₃。

3. The high-performance composite material honeycomb ceramic of claim 1, wherein the cordierite is prepared from raw material and clinker by sol-gel method to obtain high-purity cordierite clinker, which comprises: the product is prepared by reacting industrial pure organosilicon with 99.8 percent of aluminum nitrate and magnesium nitrate with the purity of 99.9 percent.

4. The high performance composite honeycomb ceramic of claim 1, wherein the aluminum titanate used is in accordance with the aluminum titanate set of theoretical standardsThe ingredient is TiO₂And Al₂O₃As raw material, mineralizer and inhibitor are introduced and synthesized at 1350-1400 ℃.

5. The high performance composite honeycomb ceramic of claim 1, whereinthe mineralizer is MgF₂And the stabilizer is MgO.

6. A method for preparing the high-performance composite material honeycomb ceramic as claimed in claim 1, wherein the cordierite obtained by the synthesis reaction is mixed with aluminum titanate and ZrSiO₃、ZrO₂Yttrium oxide (Y)₂O₃)、Fe₂O₃All become clinker, the calcining temperature is 1300-1400 ℃, the raw materials are mixed, ball milled and crushed to 350-400 mesh sieve, the raw material of cordierite is prepared by using high-purity raw talc and kaolin α -Al₂O₃The three materials are mixed according to the pure theory of cordierite, ball milled and sieved with 300 meshes (the fineness is 5-10um), put in a polygonal pool water which is larger than the hexagon, mixed with clinker powder according to the proportion of clinker to raw material (70-80) to (30-20), stirred for 2-4 hours, uniformly and filter-pressed and dehydrated to form a mud cake, the water content of the mud cake is 24-28%, the mud cake is put in a rotting room for half a month, the temperature is controlled at 20-25 ℃, the humidity is 70-90%, and the dark room is sealed. 0.1 to 0.5 percent of plasticizer CMC, 1 to 5 percent of glycerin, 0.1 to 0.5 percent of bonding agent MC, polyvinyl alcohol and composite phosphate ester, and pore-increasing agent: starch, dextrin and flour 1-10 wt%, vacuum pugging for 2-4 times, and aging in an aging room for 24 hrAdding 2-10% lubricant such as adeps Caprae Seu Ovis, oleum Verniciae Fordii, PEG-400 type, vacuum refining, extrusion molding, drying, sintering at 1300-1400 deg.C for 1-2 hr, and oxidizing flame sintering.