CN102765949B - Light-weight cordierite castable and preparation method thereof - Google Patents

Abstract

The invention relates to a cordierite lightweight pouring material and a preparation method thereof. The technical solution is: 40~70wt% porous cordierite ceramic particles, 20~48wt% cordierite ceramic fine powder, 2~10wt% calcium aluminate cement, 2~4wt% talc fine powder, 2~4wt% % silica powder and 2~4wt% activated α-alumina micropowder as raw materials, add 8~20wt% water and 0.02~1wt% water reducing agent of the raw materials, stir evenly, and cast; Dry naturally for 24 hours, then dry at 110°C for 8-48 hours. The product prepared by the present invention not only has the advantages of high apparent porosity, small average pore diameter, high strength, low thermal conductivity, good thermal shock stability, and strong resistance to medium erosion, but also has the advantages of convenient construction, environmental friendliness, apparent porosity and With the advantages of controllable pore size and small volume change after firing, it is suitable for the permanent layer or working layer of high-temperature kiln or container with working temperature lower than 1340°C.

Description

A kind of cordierite lightweight castable and preparation method thereof

technical field

The invention belongs to the technical field of lightweight castables. In particular, it relates to a cordierite lightweight castable and a preparation method thereof.

Background technique

Cordierite is a silicate mineral, its theoretical composition is 2MgO·2Al ₂ O ₃ ·5SiO ₂ , it has a small coefficient of thermal expansion, excellent thermal shock resistance, low thermal conductivity and good chemical stability. With the increasing requirements for energy saving and emission reduction, the research on environmentally friendly and efficient lightweight castables has attracted more and more attention. At present, research on cordierite lightweight materials at home and abroad mainly focuses on cordierite porous ceramic materials and cordierite lightweight refractory bricks. The former uses fly ash and coal gangue as raw materials to prepare cordierite porous materials (Wang Qi et al. Preparation of cordierite porous materials with fly ash and magnesite at low temperature. Journal of Silicates, 2012, 40 (5): 745-751), the latter is like a kind of cordierite lightweight aggregate brick (Xin Guozhi. Cordierite light Application of quality aggregate bricks in tunnel kiln car. Jiangsu Ceramics, 1995,70(3):21-22). The cordierite lightweight materials prepared by these technologies are all shaped products, which cannot prepare refractory materials with complex structures, nor can they be cast on site.

Castable is a kind of unshaped refractory material, which has the advantages of easy construction, not limited by the shape of the kiln structure, and can be conveniently made into different shapes of furnace linings. In traditional castables, dense materials are often used as aggregates. Dense castables have high thermal conductivity and high density, which waste a lot of energy and resources. At the same time, during the use of dense castables, the erosive medium first erodes the matrix. The matrix surrounds the aggregate, and when the matrix is eroded into a metamorphic layer, the aggregate flakes out of the castable along with the matrix. Therefore, under the conditions of direct fire and the presence of corrosive media, the effect of dense aggregate is not obvious. In terms of lightweight unshaped refractory materials, various lightweight castables have been studied: such as vermiculite, perlite, ceramsite, refractory lightweight aggregate and fiber castables. They have a lower thermal conductivity than dense castables and can be used as insulating materials. However, their thermal shock stability is poor, and their ability to resist flame erosion and medium erosion is poor, so they cannot be directly used in parts that are prone to fire, have aggressive media, and have large temperature fluctuations.

Contents of the invention

The purpose of the present invention is to overcome the defects of the prior art, and the purpose is to provide a method for preparing a cordierite lightweight castable with a simple preparation process. The cordierite lightweight castable prepared by this method has both high apparent porosity and small average pore size , high strength, low thermal conductivity, good thermal shock stability and strong resistance to medium erosion, and has the advantages of environmental friendliness, controllable apparent porosity and pore size, and small volume change after firing.

In order to achieve the above object, the technical solution adopted in the present invention is: with 40~70wt% porous cordierite ceramic particles, 20~48wt% cordierite ceramic fine powder, 2~10wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silica micropowder and 2~4wt% activated α-alumina micropowder are raw materials, plus 8~20wt% water of the raw material and 0.02~1wt% water reducer of the raw material, Stir evenly and pour into molding; the molded green body is naturally dried for 24 hours, and then dried at 110°C for 8 to 48 hours.

The preparation method of porous cordierite ceramic particles and cordierite ceramic fine powder is: 8~12wt% coal gangue powder, 33~37wt% Al(OH) ₃ powder, 8~12wt% talcum powder, 13~17wt% Mix magnesite powder with 28~32wt% silica powder, add 3~12wt% water of the above mixture, stir evenly, press and form; then dry the formed body at 110°C for 8~36 hours, and then Firing at 1300-1400°C for 1-6 hours to obtain porous cordierite ceramics. Finally, the porous cordierite ceramics are crushed and sieved; particles with a particle size of 8-0.1 mm are selected as porous cordierite ceramic particles, and fine powders with a particle size of less than 88 μm are selected as cordierite ceramic fine powder.

The particle size of the calcium aluminate cement is less than 88 μm.

The particle size of the talc fine powder is less than 88 μm.

The silicon oxide content of the silicon oxide micropowder is greater than 92wt%, and the particle size is less than 4 μm.

The alumina content of the activated α-alumina micropowder is greater than 97wt%, and the particle size is less than 4 μm.

The water reducer is at least one of sodium tripolyphosphate, sodium hexametaphosphate, dispersible alumina and polycarboxylate water reducer.

Adopting the above-mentioned technical scheme, the present invention adopts the patent technology of "a porous cordierite ceramic material and its preparation method (CN201110038289.2)" applied by the applicant to prepare porous cordierite ceramic particles and cordierite ceramic fine powder. The cordierite ceramic particles are porous aggregates and the cordierite ceramic fine powder is mainly used as a dense matrix to prepare lightweight castables, and the preparation process is simple. The chemical composition of the prepared product is mainly MgO, Al ₂ O ₃ and SiO ₂ , and its main crystal phase is cordierite. The material prepared by the invention not only has high strength and thermal insulation performance, but also has good thermal shock stability and medium corrosion resistance.

Therefore, the preparation process of the present invention is simple, and the prepared cordierite lightweight castable has the advantages of convenient construction, environmental friendliness, controllable apparent porosity and pore size, and small volume change after firing, and also has high apparent porosity, average pore diameter Small size, high strength, low thermal conductivity, good thermal shock stability and strong resistance to medium erosion. The cordierite lightweight casting material prepared by the invention is suitable for the permanent layer and the working layer of high-temperature kilns or containers whose working temperature is lower than 1340°C.

Detailed ways

The present invention will be further described below in conjunction with specific embodiment, not limiting to protection scope:

In order to avoid duplication, first the raw materials in this specific embodiment are described as follows, and are not repeated in the examples:

The particle size of calcium aluminate cement is less than 88 μm; the particle size of talc fine powder is less than 88 μm; the silicon oxide content of silica powder is more than 92wt%, and the particle size is less than 4 μm; less than 4μm.

The preparation method of porous cordierite ceramic particles and cordierite ceramic fine powder is: mix 8~12wt% coal gangue powder, 33~37wt% Al(OH) ₃ powder, 8~12wt% talcum powder, 13~17wt% magnesite Mix mineral powder and 28~32wt% silica powder, add 3~12wt% water of the above mixture, stir evenly, and press to form; then dry the formed green body at 110°C for 8~36 hours, and then dry it at 1300~1400 Under the condition of ℃ for 1~6 hours and firing, the porous cordierite ceramics are obtained. Finally, the porous cordierite ceramics are crushed and sieved; particles with a particle size of 8-0.1 mm are selected as porous cordierite ceramic particles, and fine powders with a particle size of less than 88 μm are selected as cordierite ceramic fine powder.

Example 1

A cordierite lightweight castable and its preparation method: 50~70wt% porous cordierite ceramic particles, 20~38wt% cordierite ceramic fine powder, 2~6wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silica fine powder and 2~4wt% activated α-alumina fine powder are raw materials, plus 8~12wt% water of the raw material and 0.02~0.4wt% sodium tripolyphosphate of the raw material , Stir evenly, and pour into molding; the molded green body is naturally dried for 24 hours, and then dried at 110°C for 8 to 18 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 35-40%, and the average pore diameter is 10-20 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 8-5mm accounts for 8-12wt% of the raw material, 5 ~3mm accounts for 18~24wt% of raw materials, 3~1mm accounts for 18~24wt% of raw materials, and 1~0.1mm accounts for 6~10wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 35-42%, a bulk density of 1.40-1.60g/cm ³ and a flexural strength of 3-6MPa was obtained; Firing under the same conditions, the holding time is 2~6 hours, and the apparent porosity is 34~44%, the bulk density is 1.39~1.61g/cm ³ , the average pore diameter is 10~20μm and the flexural strength is 8~15MPa. Bluestone lightweight castable.

Example 2

A cordierite lightweight castable and its preparation method: 40~60wt% porous cordierite ceramic particles, 25~43wt% cordierite ceramic fine powder, 4~8wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silicon oxide fine powder and 2~4wt% activated α-alumina fine powder are raw materials, plus 12~16wt% water of the raw material and 0.1~0.3wt% sodium tripolyphosphate of the raw material and 0.1~0.3wt% sodium hexametaphosphate, stir evenly, and pour into molding; the molded green body is naturally dried for 24 hours, and then dried at 110°C for 16~32 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 38-46%, and the average pore diameter is 20-30 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 5-3mm accounts for 15-22wt% of the raw material, 3 ~1mm accounts for 15~22wt% of raw materials, and 1~0.1mm accounts for 10~16wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 40-48%, a bulk density of 1.34-1.40 g/cm ³ and a flexural strength of 2-4 MPa was obtained. After being fired at 1300~1410℃, the holding time is 3~8 hours, the apparent porosity is 40~50%, the bulk density is 1.33~1.40g/cm ³ , the average pore diameter is 20~30μm and the flexural strength is 5~10MPa cordierite lightweight castable.

Example 3

A cordierite lightweight castable and its preparation method: 40-60wt% porous cordierite ceramic particles, 28-48wt% cordierite ceramic fine powder, 6-10wt% calcium aluminate cement, 2-4wt% Talc fine powder, 2~4wt% silica micropowder and 2~4wt% activated α-alumina micropowder are raw materials, plus 16~20wt% water of the raw material and 0.5~1wt% dispersible alumina of the raw material, Stir evenly and pour into molding; the molded green body is naturally dried for 24 hours, and then dried at 110°C for 30-48 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 45-55%, and the average pore diameter is 15-25 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 3-1mm accounts for 15-25wt% of the raw material, 1 ~0.1mm accounts for 25~35wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 45-58%, a bulk density of 1.22-1.40g/cm ³ , and a flexural strength of 1-3MPa was obtained; Firing under the same conditions, the holding time is 3~8 hours, and the apparent porosity is 44~60%, the bulk density is 1.21~1.39g/cm ³ , the average pore diameter is 15~25μm, and the flexural strength is 4~8MPa. Bluestone lightweight castable.

Example 4

A cordierite lightweight castable and its preparation method: 40~60wt% porous cordierite ceramic particles, 25~43wt% cordierite ceramic fine powder, 4~8wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silica fine powder and 2~4wt% activated α-alumina fine powder are raw materials, plus 13~17wt% water of the raw material and 0.2~0.8wt% dispersible alumina of the raw material Mix with 0.05~0.15wt% polycarboxylate water reducer, stir evenly, pour into molding, dry the molded body naturally for 24 hours, and then dry at 110°C for 16~32 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 40-45%, and the average pore diameter is 10-20 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 5-3mm accounts for 15-22wt% of the raw material, 3 ~1mm accounts for 15~22wt% of raw materials, and 1~0.1mm accounts for 10~16wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 38-47%, a bulk density of 1.34-1.42g/cm ³ and a flexural strength of 2-6MPa was obtained; Firing under the same conditions, the holding time is 2~6 hours, and the apparent porosity is 39~48%, the bulk density is 1.34~1.41g/cm ³ , the average pore diameter is 10~20μm and the flexural strength is 7~12MPa. Bluestone lightweight castable.

Example 5

A cordierite lightweight castable and its preparation method: 50~70wt% porous cordierite ceramic particles, 20~38wt% cordierite ceramic fine powder, 2~6wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silica micropowder and 2~4wt% activated α-alumina micropowder are raw materials, plus 11~16wt% water of said raw material and 0.1~0.3wt% of said raw material sodium tripolyphosphate and 0.1~0.3wt% sodium hexametaphosphate, stir evenly, and pour into molding; the molded green body is naturally dried for 24 hours, and then dried at 110°C for 8~18 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 40-45%, and the average pore diameter is 10-20 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 8-5mm is 8-12wt% of the raw material, 5 ~3mm is 18~24wt% of raw material, 3~1mm is 18~24wt% of raw material, 1~0.1mm is 6~10wt% of raw material;

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 39-46%, a bulk density of 1.37-1.41g/cm ³ and a flexural strength of 4-7MPa was obtained; Firing under the same conditions, the holding time is 3~8 hours, and the apparent porosity is 40~46%, the bulk density is 1.34~1.40g/cm ³ , the average pore diameter is 10~20μm and the flexural strength is 9~16MPa. Bluestone lightweight castable.

Example 6

A cordierite lightweight castable and its preparation method: 40~60wt% porous cordierite ceramic particles, 25~43wt% cordierite ceramic fine powder, 4~8wt% calcium aluminate cement, 2~4wt% Talc fine powder, 2~4wt% silicon oxide fine powder and 2~4wt% activated α-alumina fine powder are raw materials, plus 14~18wt% water of the raw material and 0.1~0.3wt% sodium tripolyphosphate of the raw material , 0.1~0.3wt% sodium hexametaphosphate and 0.1~0.3wt% dispersible alumina, stir evenly, and pour into molding; the formed green body is naturally dried for 24 hours, and then dried at 110°C for 28~45 hours .

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 45-55%, and the average pore diameter is 15-25 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 5-3mm accounts for 15-22wt% of the raw material, 3 ~1mm accounts for 15~22wt% of raw materials, and 1~0.1mm accounts for 10~16wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 43-55%, a bulk density of 1.24-1.42g/cm ³ and a flexural strength of 2-4MPa was obtained; Firing under the same conditions, the holding time is 3~8 hours, and the apparent porosity is 42~58%, the bulk density is 1.23~1.40g/cm ³ , the average pore diameter is 15~25μm and the flexural strength is 5~10MPa. Bluestone lightweight castable.

Example 7

A cordierite lightweight castable and its preparation method: 40-60wt% porous cordierite ceramic particles, 28-48wt% cordierite ceramic fine powder, 6-10wt% calcium aluminate cement, 2-4wt% Talc fine powder, 2~4wt% silicon oxide fine powder and 2~4wt% activated α-alumina fine powder are raw materials, plus 11~16wt% water of the raw material and 0.1~0.2wt% sodium tripolyphosphate of the raw material , 0.1~0.2wt% sodium hexametaphosphate, 0.1~0.2wt% dispersible alumina and 0.05~0.1wt% polycarboxylate water reducing agent, stir evenly, pouring molding; the green body after molding is naturally dried 24 hours, then dry at 110°C for 15-30 hours.

In this embodiment: the apparent porosity of the porous cordierite ceramic particles is 40-45%, and the average pore diameter is 10-20 μm; the particle gradation ratio of the porous cordierite ceramic particles is: 3-1mm accounts for 15-25wt% of the raw material, 1 ~0.1mm accounts for 25~35wt% of raw materials.

Using the technical solution described in this example, a cordierite lightweight castable with an apparent porosity of 37-46%, a bulk density of 1.35-1.43g/cm ³ and a flexural strength of 3-6MPa was obtained; Firing under the same conditions, the holding time is 2~6 hours, and the apparent porosity is 38~46%, the bulk density is 1.35~1.43g/cm ³ , the average pore diameter is 10~20μm and the flexural strength is 8~14MPa. Bluestone lightweight castable.

This specific embodiment adopts the patented technology of "a porous cordierite ceramic material and its preparation method (CN201110038289.2)" applied by the applicant to prepare porous cordierite ceramic particles and fine powder of cordierite ceramics, and the prepared porous cordierite ceramics The cordierite lightweight pouring material is prepared for the porous aggregate and the cordierite ceramic fine powder as a matrix, and the preparation process is simple. The chemical composition of the prepared product is mainly MgO, Al ₂ O ₃ and SiO ₂ , and its main crystal phase is cordierite. The material prepared by this embodiment not only has high strength and thermal insulation performance, but also has good thermal shock stability and medium corrosion resistance.

Therefore, the preparation process of this specific embodiment is simple, and the prepared cordierite lightweight castable has the advantages of convenient construction, environmental friendliness, controllable apparent porosity and pore size, and small volume change after firing, and also has high apparent porosity, The advantages of small average pore size, high strength, low thermal conductivity, good thermal shock stability and strong resistance to medium erosion. The cordierite lightweight castable prepared in this specific embodiment is suitable for the permanent layer and the working layer of high-temperature kilns or containers whose working temperature is lower than 1340°C.

Claims (7)

1. a preparation method of cordierite lightweight castable, is characterized in that with the porous cordierite ceramic particle of 40～70wt%, the cordierite ceramic fine powder of 20～48wt%, the calcium aluminate cement of 2～10wt%, 2~4wt% talc fine powder, 2~4wt% silica micropowder and 2~4wt% activated α-alumina micropowder are raw materials, plus 8~20wt% water of the raw material and 0.02~1wt% of the raw material Water reducing agent, stir evenly, pour into molding, the molded body is naturally dried for 24 hours, and then dried at 110°C for 8 to 48 hours; The preparation method of porous cordierite ceramic particles and cordierite ceramic fine powder is: 8~12wt% coal gangue powder, 33~37wt% Al(OH) ₃ powder, 8~12wt% talcum powder, 13~17wt% Mix magnesite powder with 28~32wt% silica powder, add 3~12wt% water of the above mixture, stir evenly, press and form; then dry the formed body at 110°C for 8~36 hours, and then Firing at 1300~1400°C for 1~6 hours, the porous cordierite ceramics are obtained; finally, the porous cordierite ceramics are crushed and sieved, and the particles with a particle size of 8~0.1mm are selected as porous cordierite ceramic particles. The fine powder whose particle size is less than 88 μm is selected as cordierite ceramic fine powder. 2. The preparation method of cordierite lightweight castable according to claim 1, characterized in that the particle size of the calcium aluminate cement is less than 88 μm. 3. The preparation method of cordierite lightweight castable according to claim 1, characterized in that the particle diameter of the talc fine powder is less than 88 μm. 4. the preparation method of cordierite lightweight castable according to claim 1, is characterized in that the silicon oxide content of described silicon oxide micropowder is greater than 92 wt%, and particle diameter is less than 4 μ m. 5. the preparation method of cordierite lightweight castable according to claim 1, is characterized in that the alumina content of described activated α-alumina micropowder is greater than 97 wt%, and particle diameter is less than 4 μ m. 6. The preparation method of cordierite lightweight castable according to claim 1, characterized in that said water reducer is sodium tripolyphosphate, sodium hexametaphosphate, dispersible alumina and polycarboxylate water reducer more than one of them. 7. The cordierite lightweight castable prepared by the preparation method of the cordierite lightweight castable according to any one of claims 1 to 6.