CN112390616A

CN112390616A - Sintering forming process of refractory material

Info

Publication number: CN112390616A
Application number: CN202011266658.9A
Authority: CN
Inventors: 李善平; 李欣
Original assignee: Xinhua Dongtai Special Refractory Co ltd
Current assignee: Xinhua Dongtai Special Refractory Co ltd
Priority date: 2020-11-13
Filing date: 2020-11-13
Publication date: 2021-02-23

Abstract

The invention discloses a sintering and molding process of a refractory material, which utilizes a proportional mixture of magnesium oxide, silicon carbide, boron carbide, aluminum nitride or silicon nitride with the grain diameter less than 1mm as a matrix; the method comprises the following steps of (1) utilizing a proportional mixture of three types of alkali-resistant clay, calcined bauxite and cordierite with different particle sizes as aggregate; the composite material is prepared by taking a mixture of perlite, vermiculite and foamed alumina with the particle size of 1-3 mm as a light filler and mixing the mixture with a two-component binding agent, wherein the carbon material modified phenolic resin is added into the binding agent, the two-component binding agent is added twice to be mixed, the mixture is pressed into a refractory material green body after the mixing is finished, and the refractory material green body is naturally cooled to room temperature along with a furnace after three-stage heat treatment to obtain a finished product. The refractory material prepared by the method has excellent thermal shock property and compactness, so that the material has the characteristic of stable crack propagation, the compactness and the thermal shock property of a product are improved, and the mechanical property is also improved.

Description

Sintering forming process of refractory material

Technical Field

The invention relates to the technical field of refractory materials, in particular to a sintering forming process of a refractory material.

Background

The refractory material is an inorganic non-metallic material with refractoriness of not less than 1580 ℃, is a basic material serving for high-temperature technology, and is used as a structural material of thermal equipment such as a high-temperature kiln and the like, and a material of industrial high-temperature containers and components. The refractory material is widely applied to the relevant fields of high-temperature industries such as steel, cement, ceramics, glass, chemical engineering, nonferrous materials and the like, is an important basic material and an indispensable important supporting material of the high-temperature industry, and has an important position in a modern industrial system. With the rapid development of the basic industry of China in recent years, China has become the largest refractory material producing and consuming countries in the world.

In the prior art, most of the refractory materials are made from natural ores (such as chamotte, silica, magnesite and dolomite), and some industrial materials and artificial materials (such as industrial alumina, silicon carbide, synthetic mullite and synthetic spinel) are used, so that the variety of the refractory materials is very wide. The refractory materials can be divided into ordinary, high-grade and special-grade refractory products according to the refractoriness, and can be divided into light and heavy refractory materials according to the density, along with the technical progress of the refractory materials and the continuous upgrade of high-temperature industrial production processes and equipment of steel, cement, glass, color and the like, better requirements are provided for the quality level of the refractory materials, the market space of the low-grade refractory materials is continuously shrunk, the specific gravity of the high-grade refractory materials is continuously expanded, wherein the high-demand-degree refractory materials are mainly light high-grade or special-grade refractory materials, and the refractory materials are required to bear corresponding physicochemical change and mechanical action besides light quality and stable refractory performance. The poor mechanical toughness of the common inorganic non-metallic materials is a problem commonly existing in inorganic non-metals and materials, so that the mechanical toughness of the refractory materials of the inorganic non-metallic materials is also poor, the thermal shock resistance of the refractory materials at high temperature is influenced, the refractory materials are easy to crack and peel in the using process, and the service life of the refractory materials is shortened.

Therefore, how to improve the structural strength, stability and thermal shock resistance of the related refractory material on the basis of the prior art has important significance.

Disclosure of Invention

The technical problem to be solved by the present invention is to provide a sintering molding process of refractory material to solve the above-mentioned drawbacks in the prior art.

The technical problem solved by the invention is realized by adopting the following technical scheme:

a sintering molding process of a refractory material is prepared by using the following raw materials in parts by mass:

matrix: 30-35 parts of magnesium oxide, 10-17 parts of silicon carbide, 3-7 parts of boron carbide and 1-3 parts of aluminum nitride or silicon nitride; each component in the matrix is a particulate matter with the particle size less than 1 mm;

aggregate: 75-90 parts of alkali-resistant clay, 10-15 parts of calcined bauxite and 7-9 parts of cordierite; wherein the alkali-resistant clay is Al₂O₃25% -30% of alkali-resistant clay, and crushing cordierite into powder, and sieving and grading; the aggregate comprises 30-40% of particles with the particle size of 1.0-3.0 mm, 40-50% of particles with the particle size of 0.1-1.0 mm and the balance of particles with the particle size of less than 0.1mm, wherein the particles with different particle sizes are uniformly distributed in the proportions of alkali-resistant clay, calcined bauxite, cordierite and the like;

light filler: 40-60 parts of perlite, 20-40 parts of vermiculite and 15-25 parts of foamed aluminum oxide, wherein the light filler is a particulate matter with the particle size of 1-3 mm;

the binding agent is a two-component binding agent: the component A is 20-30 parts of carbon material modified phenolic resin, and the component B is 10-15 parts of calcium silicate cement, 9-10 parts of polyvinyl alcohol, 3-5 parts of ethylene glycol, 3-5 parts of sodium lignosulfonate and 30-50 parts of water;

the carbon material for phenolic resin modification is one of graphene, nano carbon black and carbon nano tubes or a mixture of any proportion, the carbon material is added into phenolic resin for ultrasonic-assisted dispersion for 90-120 min to obtain the phenolic resin modified by the carbon material, and the adding amount of the carbon material in the phenolic resin is 0.3-0.5%;

during preparation, 20-30% of matrix by mass, 30-40% of aggregate by mass and the balance of light filler are mixed according to the proportion of 100% of the total mass to prepare a dry refractory material, meanwhile, the component B in the binder is mixed to prepare a slurry, the dry refractory material and the slurry are mixed according to the proportion of 6: 1-8: 1 by mass and then stirred for 60-90 min, then the component A in the binder is added and stirred, and the raw materials are fed into a mold to be pressed into a green refractory material after being stirred for 20-30 min;

putting the molded refractory material green body into a furnace for heat treatment, carrying out three-stage heat treatment during the heat treatment, controlling the temperature of a low-temperature region to be 120-200 ℃, the heating rate to be 30 ℃/h, and carrying out heat preservation for 30-50 min, the temperature of a middle-temperature region to be 450-600 ℃, the heating rate to be 50 ℃/h, and carrying out heat preservation for 90-120 min, the temperature of a high-temperature region to be 1200-1650 ℃, the heating rate to be 80 ℃/h, and carrying out heat preservation for 3-5 h; and naturally cooling to room temperature along with the furnace after the heat treatment is finished to obtain a finished product.

As a further limitation, when the refractory material dry material is mixed, 1-3% of silicon powder and 0.3-0.5% of white carbon black in the total mass of the mixture can be added to improve the sintering performance of the molded refractory material green body and improve the anti-cracking performance of the finished refractory material.

By way of further limitation, the die is a slab die or a green brick die with a thickness greater than 15 mm.

The component B in the binder is further limited to be added with a polycarboxylic acid water reducing agent accounting for 0.03-1.0% of the total mass of the components and kerosene accounting for 0.1-0.3% of the total mass of the components as a dust inhibitor.

Has the advantages that: the sintering forming process of the refractory material can be used for preparing refractory bricks or refractory plates, the prepared refractory material forms a reinforced composition by combining base materials with different particle sizes and aggregates, so that the integrity of the overall structure of the refractory material is improved, the compactness of the refractory material is improved under the condition of ensuring the refractory performance, the refractory material has excellent thermal shock resistance and crack resistance, and the use of the light filler can be used for reducing the quality of the refractory material, eliminating internal mechanical stress after forming and further improving the fracture toughness; the use of the two-component binder and the phenolic resin modified by the carbon material can lead the phenolic resin to form secondary carbon with a glassy mosaic structure with larger grain size and smaller interlayer spacing after pyrolysis and carbonization, or form nano carbon fiber and a nano carbon tube in situ, thereby achieving the purpose of obviously improving the thermal shock resistance and the high-temperature strength of the low-carbon magnesia carbon refractory material.

Detailed Description

In order to make the technical means, the creation characteristics, the achievement purposes and the effects of the invention easy to understand, the invention is further described with the specific embodiments.

The first embodiment is as follows:

the refractory material is prepared from the following raw materials in parts by mass:

matrix: 30 parts of magnesium oxide, 10 parts of silicon carbide, 3 parts of boron carbide and 1 part of aluminum nitride; each component in the matrix is a particulate matter with the particle size less than 1 mm;

aggregate: 75 parts of alkali-resistant clay, 10 parts of calcined bauxite and 7 parts of cordierite; wherein the alkali-resistant clay is Al₂O₃Alkali-resistant clay with the content of 25 percent, and cordierite is crushed into powder and sieved and classified; the proportion of particles with the particle size of 1.0-3.0 mm in the aggregate is 30%, the proportion of particles with the particle size of 0.1mm is 40%, the proportion of 40% of particles with the particle size of less than 0.1mm, and the particles with different particle sizes are uniformly distributed in the proportions of alkali-resistant clay, calcined bauxite, cordierite and the like;

light filler: 40 parts of perlite, 20 parts of vermiculite and 15 parts of foamed alumina, wherein the light filler is a particulate matter with the particle size of 2-3 mm;

the binding agent is a two-component binding agent:

the component A is 20 parts of carbon material modified phenolic resin, the modified phenolic resin is added with carbon material accounting for 0.3 percent of the weight of the phenolic resin, the carbon material is a mixture of carbon nano tubes and nano carbon black in a mass ratio of 3:1, and the carbon material is added into the phenolic resin to be subjected to ultrasonic-assisted dispersion for 90min to obtain the carbon material modified phenolic resin;

the component B comprises 10 parts of calcium silicate cement, 9 parts of polyvinyl alcohol, 3 parts of ethylene glycol, 3 parts of sodium lignosulfonate and 30 parts of water;

during preparation, 20 mass percent of matrix, 30 mass percent of aggregate and 50 mass percent of light filler are mixed to prepare dry refractory material, meanwhile, the component B in the binding agent is mixed to prepare slurry, the dry refractory material and the slurry are mixed according to the mass ratio of 6:1 and then stirred for 60min, then the component A in the binding agent is added and stirred, and after stirring for 20min, the raw materials are put into a brick blank mold with the length and width of 230mm multiplied by 114mm multiplied by 65mm to be pressed into a refractory material green blank;

putting the molded refractory material green body into a furnace for heat treatment, carrying out three-stage heat treatment during the heat treatment, controlling the temperature of a low-temperature region to be 120 ℃, the heating rate to be 30 ℃/h, and carrying out heat preservation for 30min, the temperature of a medium-temperature region to be 450 ℃, the heating rate to be 50 ℃/h, and carrying out heat preservation for 90min, the temperature of a high-temperature region to be 1200 ℃, the heating rate to be 80 ℃/h, and carrying out heat preservation for 3 h; and naturally cooling to room temperature along with the furnace after the heat treatment is finished to obtain the finished product of the refractory brick.

Example two:

matrix: 35 parts of magnesium oxide, 17 parts of silicon carbide, 7 parts of boron carbide and 3 parts of aluminum nitride; each component in the matrix is a particulate matter with the particle size less than 1 mm;

aggregate: 90 parts of alkali-resistant clay, 15 parts of calcined bauxite and 9 parts of cordierite; wherein the alkali-resistant clay is Al₂O₃30 percent of alkali-resistant clay and cordierite are crushed into powder and sieved and classified; the proportion of particles with the particle size of 1.0-3.0 mm in the aggregate is 40%, the proportion of particles with the particle size of 0.1mm is 50%, and the proportion of particles with the particle size of 10% is less than 0.1mm, and the particles with different particle sizes are uniformly distributed in the proportions of alkali-resistant clay, calcined bauxite, cordierite and the like;

light filler: 60 parts of perlite, 40 parts of vermiculite and 25 parts of foamed aluminum oxide, wherein the light filler is a particulate matter with the particle size of 1-3 mm;

the binding agent is a two-component binding agent:

the component A is 30 parts of carbon material modified phenolic resin, the modified phenolic resin is added with carbon material accounting for 0.5 percent of the weight of the phenolic resin, the carbon material is a mixture of carbon nano tubes and nano carbon black in a mass ratio of 3:1, and the carbon material is added into the phenolic resin to be subjected to ultrasonic-assisted dispersion for 120min to obtain the carbon material modified phenolic resin;

the component B comprises 15 parts of calcium silicate cement, 10 parts of polyvinyl alcohol, 5 parts of ethylene glycol, 5 parts of sodium lignosulfonate and 50 parts of water;

during preparation, mixing 30% of matrix, 40% of aggregate and 30% of light filler by mass to prepare dry refractory material, simultaneously mixing the component B in the binder to prepare slurry, stirring the dry refractory material and the slurry according to the mass ratio of 8:1, stirring for 90min, adding the component A in the binder, stirring for 30min, and pressing the raw materials into a brick blank mold with the length and width of 230mm multiplied by 114mm multiplied by 65mm to prepare a refractory blank;

putting the molded refractory material green body into a furnace for heat treatment, carrying out three-stage heat treatment during the heat treatment, controlling the temperature of a low-temperature region to be 200 ℃, the heating rate to be 30 ℃/h, and carrying out heat preservation for 50min, the temperature of a medium-temperature region to be 600 ℃, the heating rate to be 50 ℃/h, and carrying out heat preservation for 120min, the temperature of a high-temperature region to be 1650 ℃, the heating rate to be 80 ℃/h, and carrying out heat preservation for 5 h; and naturally cooling to room temperature along with the furnace after the heat treatment is finished to obtain the finished product of the refractory brick.

Example three:

matrix: 32 parts of magnesium oxide, 15 parts of silicon carbide, 6 parts of boron carbide and 2 parts of aluminum nitride; each component in the matrix is a particulate matter with the particle size less than 1 mm;

aggregate: 80 parts of alkali-resistant clay, 12 parts of calcined bauxite and 8 parts of cordierite; wherein the alkali-resistant clay is Al₂O₃Alkali-resistant clay with 28% content, cordierite is crushed into powder and sieved and classified; the proportion of particles with the particle size of 1.0-3.0 mm in the aggregate is 35%, the proportion of particles with the particle size of 0.1mm is 45%, and the proportion of 20% of particles with the particle size of less than 0.1mm in the aggregate is uniform, and the particles with different particle sizes are distributed in the alkali-resistant clay, the calcined bauxite, the cordierite and the like in proportion;

light filler: 50 parts of perlite, 30 parts of vermiculite and 20 parts of foamed aluminum oxide, wherein the light filler is a particulate matter with the particle size of 1-3 mm;

the binding agent is a two-component binding agent:

the component A is 25 parts of phenolic resin modified by a carbon material, the modified phenolic resin is added with the carbon material accounting for 0.4 percent of the weight of the phenolic resin, the carbon material is a mixture of carbon nano tubes and nano carbon black in a mass ratio of 3:1, and the carbon material is added into the phenolic resin to be subjected to ultrasonic-assisted dispersion for 100min to obtain the phenolic resin modified by the carbon material;

the component B comprises 12 parts of calcium silicate cement, 9.5 parts of polyvinyl alcohol, 4 parts of ethylene glycol, 4 parts of sodium lignosulfonate and 40 parts of water;

during preparation, mixing 25 mass percent of matrix, 35 mass percent of aggregate and 40 mass percent of light filler to prepare dry refractory material, simultaneously mixing the component B in the binder to prepare slurry, stirring the dry refractory material and the slurry according to the mass ratio of 7:1, stirring for 80min, adding the component A in the binder, stirring for 25min, and pressing the raw materials into a brick blank mold with the length, width and height of 230mm multiplied by 114mm multiplied by 65mm to prepare a refractory green blank;

putting the molded refractory material green body into a furnace for heat treatment, carrying out three-stage heat treatment during the heat treatment, controlling the temperature of a low-temperature region to be 160 ℃, the heating rate to be 30 ℃/h, and carrying out heat preservation for 40min, the temperature of a medium-temperature region to be 550 ℃, the heating rate to be 50 ℃/h, and carrying out heat preservation for 110min, the temperature of a high-temperature region to be 1450 ℃, the heating rate to be 80 ℃/h, and carrying out heat preservation for 4 h; and naturally cooling to room temperature along with the furnace after the heat treatment is finished to obtain the finished product of the refractory brick.

Example four:

matrix: 33 parts of magnesium oxide, 16 parts of silicon carbide, 6 parts of boron carbide and 2 parts of aluminum nitride; each component in the matrix is a particulate matter with the particle size less than 1 mm;

aggregate: 85 parts of alkali-resistant clay, 13 parts of calcined bauxite and 8 parts of cordierite; wherein the alkali-resistant clay is Al₂O₃Alkali-resistant clay with the content of 27 percent, and cordierite is crushed into powder and sieved and classified; the aggregate contains 35% of particles with the particle size of 1.0-3.0 mm, 45% of particles with the particle size of 0.1mm, and 20% of particles with the particle size less than 0.1mm, wherein the particles with different particle sizesThe particles are uniformly distributed in the alkali-resistant clay, calcined bauxite and cordierite in equal proportion;

the binding agent is a two-component binding agent:

the component A is 25 parts of phenolic resin modified by a carbon material, the modified phenolic resin is added with the carbon material accounting for 0.4 percent of the weight of the phenolic resin, the carbon material is a mixture of graphene, nano carbon black and carbon nano tubes in a mass ratio of 1:1:1, and the carbon material is added into the phenolic resin to be subjected to ultrasonic-assisted dispersion for 110min to obtain the phenolic resin modified by the carbon material;

the component B comprises 12 parts of calcium silicate cement, 10 parts of polyvinyl alcohol, 4 parts of ethylene glycol, 5 parts of sodium lignosulfonate and 45 parts of water;

putting the molded refractory material green body into a furnace for heat treatment, carrying out three-stage heat treatment during the heat treatment, controlling the temperature of a low-temperature region to be 180 ℃, the heating rate to be 30 ℃/h, and carrying out heat preservation for 40min, the temperature of a medium-temperature region to be 500 ℃, the heating rate to be 50 ℃/h, and carrying out heat preservation for 105min, the temperature of a high-temperature region to be 1350 ℃, the heating rate to be 80 ℃/h, and carrying out heat preservation for 4 h; and naturally cooling to room temperature along with the furnace after the heat treatment is finished to obtain the finished product of the refractory brick.

Example five:

the binding agent is a two-component binding agent:

during preparation, adding a matrix accounting for 25% by mass, an aggregate accounting for 35% by mass and a light filler accounting for 40% by mass into a mixing container, adding silicon powder accounting for 2% by mass of the matrix, the aggregate and the light filler and 0.4% by mass of white carbon black together, carrying out dry mixing on the mixture to prepare a dry refractory material, mixing a component B in a binding agent to prepare a slurry, stirring the dry refractory material and the slurry according to the mass ratio of 7:1, stirring for 80min, adding a component A in the binding agent, stirring for 25min, putting the raw materials into a brick blank mold with the length and width of 230mm x 114mm x 65mm, and pressing into a refractory blank;

The finished refractory bricks prepared under the technical conditions of the first to fifth examples and two commercially available refractory bricks are used as a first comparative example and a second comparative example for performance tests, and the results are as follows:

example one

Example two

EXAMPLE III

Example four

EXAMPLE five

Comparative example 1

Comparative example No. two

Porosity of the alloy

5.10%

5.70%

6.00%

6.40%

6.20%

7.80%

7.20%

Bulk density

3.24g/cm3

3.03g/cm3

3.17g/cm3

3.12g/cm3

3.09g/cm3

3.94g/cm3

4.22g/cm3

Normal temperature compressive strength (25 ℃ C.)

93.4MPa

90.2MPa

101.3MPa

101.5MPa

105.0MPa

84.2MPa

87.7MPa

High temperature compressive Strength (1100 ℃ C.)

48.4MPa

54.6MPa

58.2MPa

62.1MPa

64.7MPa

49.4MPa

42.3MPa

Normal temperature rupture strength (25 ℃ C.)

5.4MPa

5.6MPa

6.1MPa

6.4MPa

4.8MPa

4.6MPa

High temperature rupture Strength (1100 ℃ C.)

4.2MPa

4.6MPa

4.8MPa

5.1MPa

5.3MPa

3.7MPa

3.4MPa

Thermal shock stability (Water cooled)

7

8

9

10

7

6

Fire resistance rating

Special class

As can be seen from the above table, compared with the embodiment in the prior art, the technical scheme of the embodiment of the invention has lighter weight, more excellent physical strength and thermal shock resistance, and can ensure effective fire resistance.

The foregoing shows and describes the general principles, essential features, and advantages of the invention. It will be understood by those skilled in the art that the present invention is not limited to the embodiments described above, which are described in the specification and illustrated only to illustrate the principle of the present invention, but that various changes and modifications may be made therein without departing from the spirit and scope of the present invention, which fall within the scope of the invention as claimed. The scope of the invention is defined by the appended claims and equivalents thereof.

Claims

1. The sintering molding process of the refractory material is characterized by being prepared from the following raw materials in parts by mass:

2. The sintering molding process of the refractory material according to claim 1, wherein silica powder accounting for 1-3% of the total mass of the mixture and 0.3-0.5% of white carbon black are added during the mixing of the dry refractory material.

3. The process for sinter molding of a refractory material as claimed in claim 1, wherein the mold is a slab mold or a green brick mold having a thickness of more than 15 mm.

4. The sintering and molding process of the refractory material according to claim 1, wherein a polycarboxylic acid water reducing agent accounting for 0.03-1.0% of the total mass of the components is added to the component B in the binder.

5. The sintering and molding process of the refractory material according to claim 1, wherein kerosene is added as a dust suppressant in an amount of 0.1 to 0.3% by mass of the total amount of the components to the B component in the binder.