阅读说明：本技术 一种基于冷等静压湿袋法制得的透气砖及其制备方法 (Air brick prepared based on cold isostatic pressing wet bag method and preparation method thereof ) 是由 徐业兴 郭钰龙 汪正峰 郝不景 李红霞 戚静 刘振国 孙肖肖 胡国伟 于 2020-09-01 设计创作，主要内容包括：本发明涉及一种基于冷等静压湿袋法制得的透气砖及其制备方法。包括砖外层,砖外层上端设有嵌入槽,嵌入槽内嵌设有砖内芯,砖内芯周壁与嵌入槽内壁间设有下气体流道,砖内芯周壁间隔布设有多个与砖外层连接的下连接柱；砖内芯上端向上延伸至嵌入槽外,置于嵌入槽外的砖内芯包裹有透气层,砖内芯周壁与透气层间设有与下气体流道连通的上气体流道砖内芯周壁设有与透气层连接的上连接柱；砖外层底部设有导气孔,导气孔向上贯穿砖外层与下气体流道连通,导气孔还外接有导气管,导气管一端连通有气体接头,砖外层和导气管均外套有钢套；砖外层与外套于砖外层的钢套间设有火泥层。(The invention relates to an air brick prepared based on a cold isostatic pressing wet bag method and a preparation method thereof. The brick comprises an outer brick layer, wherein an embedded groove is formed in the upper end of the outer brick layer, a brick inner core is embedded in the embedded groove, a lower gas flow channel is formed between the peripheral wall of the brick inner core and the inner wall of the embedded groove, and a plurality of lower connecting columns connected with the outer brick layer are distributed on the peripheral wall of the brick inner core at intervals; the upper end of the brick inner core extends upwards to the outside of the embedded groove, the brick inner core arranged outside the embedded groove is wrapped with a ventilation layer, an upper gas flow channel communicated with the lower gas flow channel is arranged between the peripheral wall of the brick inner core and the ventilation layer, and the peripheral wall of the brick inner core is provided with an upper connecting column connected with the ventilation layer; the bottom of the outer layer of the brick is provided with an air guide hole which upwards penetrates through the outer layer of the brick and is communicated with the lower gas flow passage, the air guide hole is externally connected with a gas guide pipe, one end of the gas guide pipe is communicated with a gas joint, and the outer layer of the brick and the gas guide pipe are sleeved with steel sleeves; a fire clay layer is arranged between the outer layer of the brick and the steel sleeve sleeved outside the outer layer of the brick.)

1. The air brick prepared based on the cold isostatic pressing wet bag method is characterized in that: the brick comprises an outer brick layer (1), wherein an embedded groove (101) is formed in the upper end of the outer brick layer (1), an inner brick core (2) is embedded in the embedded groove (101), a lower gas flow channel (3) is formed between the peripheral wall of the inner brick core (2) and the inner wall of the embedded groove (101), and a plurality of lower connecting columns (4) connected with the outer brick layer (1) are distributed on the peripheral wall of the inner brick core (2) at intervals; the upper end of the brick inner core (2) extends upwards to the outside of the embedded groove (101), the brick inner core (2) arranged outside the embedded groove (101) is wrapped with a ventilation layer (5), an upper gas flow channel (6) communicated with the lower gas flow channel (3) is arranged between the peripheral wall of the brick inner core (2) and the ventilation layer (5), and an upper connecting column (7) connected with the ventilation layer (5) is arranged on the peripheral wall of the brick inner core (2); the bottom of the brick outer layer (1) is provided with an air guide hole (8), the air guide hole (8) upwards penetrates through the brick outer layer (1) and is communicated with the lower gas flow channel (3), the air guide hole (8) is also externally connected with a gas guide pipe (9), one end of the gas guide pipe (9) is communicated with a gas connector (11), and both the brick outer layer (1) and the gas guide pipe (9) are externally sleeved with a steel sleeve (10); a fire clay layer (12) is arranged between the brick outer layer (1) and the steel sleeve (10) which is sleeved outside the brick outer layer (1).

2. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: the ventilation layer (5) is externally covered with an anti-oxidation high temperature resistant layer.

3. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: the height of the steel sleeve (10) of the outer layer (1) of the outer casing brick is lower than that of the outer layer (1) of the brick; the height difference between the steel sleeve of the outer layer (1) of the outer casing brick and the outer layer (1) of the brick is 10mm-40 mm.

4. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: the length of the upper connecting column (7) is 0.8-1.5 mm; the length of the lower connecting column (4) is 0.8-1.5 mm.

5. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: the steel sleeve (10) comprises a first steel sleeve (1001) sleeved outside the brick outer layer (1), a second steel sleeve (1002) sleeved outside the air guide pipe (9), and the second steel sleeve (1002) and the first steel sleeve (1001) are welded into a whole; the silver powder layer is coated outside the second steel sleeve (1002) and the first steel sleeve (1001).

6. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: according to the parts by weight, the air-permeable layer (5) comprises 97 parts of fused magnesia, 10-15 parts of zirconium mullite, 5-15 parts of fused quartz, 2-5 parts of calcined alumina micro powder, 1-5 parts of ferrosilicon nitride, 3-6 parts of antioxidant, 5-8 parts of ignition loss additive, 8-15 parts of thermosetting liquid resin and 1-5 parts of thermoplastic phenolic resin powder.

7. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 1, wherein: according to the parts by weight, the fused magnesia comprises 20-30 parts of fused magnesia with the particle size of 3-5mm, 20-40 parts of fused magnesia with the particle size of 1-3mm and 20-40 parts of fused magnesia with the particle size of 0-1 mm;

according to the parts by weight, the fused quartz comprises 3-10 parts of fused quartz with the particle size of 0.2-0.5mm and 2-10 parts of fused quartz with the particle size of 0-0.2 mm;

the particle size of the calcined alumina micro powder is 1 um;

the grain diameter of the zirconium mullite is 0.2-0.5 mm.

8. The air brick prepared based on the cold isostatic pressing wet bag method according to claim 7, wherein: the antioxidant is one or more of metal silicon powder, aluminum powder, silicon carbide or boron carbide; the ignition loss agent adopts one or two of dextrin or paraffin powder.

9. A method for preparing an air brick prepared according to any one of claims 1 to 8 based on a cold isostatic pressing wet bag method, wherein: the method comprises the following steps:

respectively carrying out material mixing, drying and ageing on the brick inner core material mixing, the air-permeable layer material mixing and the brick outer layer material mixing to obtain a brick inner core material mixing to be used, an air-permeable layer material mixing to be used and a brick outer layer material mixing to be used;

putting the mixed material of the brick inner core into a one-step forming die, and carrying out isostatic pressing forming in a wet bag method isostatic pressing machine to obtain a brick inner core (2);

coating wax sheets on the outer surface of the brick inner core (2), arranging a plurality of through holes penetrating through the wax sheets at intervals on the wax sheets, putting the brick inner core (2) coated with the wax sheets into a secondary forming die, adding a standby air-permeable layer mixed material and a brick outer layer mixed material into corresponding positions of the secondary forming die, and performing isostatic pressing forming in a wet bag method isostatic press to obtain an air-permeable brick blank;

drilling a hole at the bottom of the air brick blank, extending the drilled hole to a wax sheet, placing for 8-12 hours, and roasting to obtain an air brick to be treated;

embedding an air duct (9) at a drill hole of the air brick to be processed, smearing fire clay on the surface of the brick outer layer (1) of the air brick to be processed, and sleeving a steel sleeve (10) on the brick outer layer (1) and the air duct (9); one end of the gas guide pipe (9) is communicated with the gas connector (11) to obtain the gas permeable brick.

10. The method of claim 9, wherein:

placing the mixed material of the inner core of the brick into a one-step forming die, and performing wet bag cold isostatic pressing, wherein the wet bag cold isostatic pressing pressure is 15MPa-30 MPa;

placing the brick inner core (2) wrapped with the wax sheet into a secondary forming die, and performing wet bag cold isostatic pressing, wherein the wet bag cold isostatic pressing pressure is 45-130 MPa;

spraying an anti-oxidation high-temperature-resistant coating on the outer surface of the air-permeable layer (5) of the air-permeable brick;

the material of the anti-oxidation high-temperature-resistant coating is a magnesium carbon material or an aluminum-magnesium carbon material;

the steel sleeve (10) comprises a first steel sleeve (1001) sleeved outside the brick outer layer (1) and a second steel sleeve (1002) sleeved on the air guide pipe (9), the second steel sleeve (1002) is welded on the first steel sleeve (1001), and silver powder is sprayed on the outer surfaces of the first steel sleeve (1001) and the second steel sleeve (1002);

the water temperature of the wet bag method isostatic pressing machine is 25-30 ℃ when the wet bag method isostatic pressing machine works;

the thickness of the wax sheet wrapped outside the brick inner core (2) is 0.5-0.8mm, the diameter of a through hole on the wax sheet is 8-10mm, and the through hole accounts for 28% of the area of the whole wax sheet;

the diameter of the air guide hole (8) is 4-6 mm;

the material of the brick outer layer (1) comprises at least one of a magnesium carbon material, an aluminum magnesium spinel material or a corundum material;

the brick inner core (2) comprises at least one of a magnesia carbon material, an aluminum-magnesium spinel material or a corundum material.

Technical Field

The invention relates to the technical field of air brick preparation, in particular to an air brick prepared based on a cold isostatic pressing wet bag method and a preparation method thereof.

Background

The air brick is positioned at the bottom of the ladle, and mainly has the functions of accelerating the stirring of molten steel in a refining working section by blowing argon into the air brick, promoting the floating of non-metallic inclusions in the molten steel under the disturbance of argon bubbles, and realizing the effect that the temperature and the components of the molten steel in the ladle tend to be uniform.

The present air brick adopts pouring or machine to press the shaping mode, and the air brick has certain difference because of the shaping pressure that each position received such as inside and outside upper and lower when the shaping, and in aspects such as pug particle size distribution, has the granule segregation phenomenon, and relatively great granule moves down, and less granule or fine powder up move, and then leads to there being the volatility in each position quality of air brick. Furthermore, the air brick all need inlay when the ladle bottom is installed in the construction at present and sit the brick the inside, protects the use, and this mode not only has increased intensity of labour in the aspect of the operation, and in the aspect of safe quality control, still can appear oozing the steel problem because of scribbling the fire clay problem between air brick and the brick of sitting moreover between the two, brings the potential safety hazard to the molten steel casting environment. At present, the used air brick mainly has a dispersion type, a slit type and a straight-through hole type, and the air brick with the three modes has the problem of blockage of air holes or molten steel entering a channel in the using process, so that the argon blowing effect of the air brick is influenced.

Therefore, in order to solve the above problems, the present invention provides an air brick prepared by a cold isostatic pressing wet bag method and a preparation method thereof.

Disclosure of Invention

The invention aims to provide an air brick prepared based on a cold isostatic pressing wet bag method and a preparation method thereof, and the air brick is designed to solve the technical problems that the existing air brick in the prior art adopts a pouring or mechanical pressing forming mode, the air brick has certain difference in forming pressure at each part of an upper part, a lower part and the like inside and outside during forming, and the quality of each part of the air brick has fluctuation due to the fact that particles are segregated in the aspects of mud material granularity distribution and the like, relatively larger particles move downwards, and smaller particles or fine powder move upwards.

The invention provides an air brick prepared based on a cold isostatic pressing wet bag method, which comprises an outer brick layer, wherein an embedded groove is arranged at the upper end of the outer brick layer, a brick inner core is embedded in the embedded groove, a lower gas flow channel is arranged between the peripheral wall of the brick inner core and the inner wall of the embedded groove, and a plurality of lower connecting columns connected with the outer brick layer are distributed on the peripheral wall of the brick inner core at intervals; the upper end of the brick inner core extends upwards to the outside of the embedded groove, the brick inner core arranged outside the embedded groove is wrapped with a ventilation layer, an upper gas flow passage communicated with the lower gas flow passage is arranged between the peripheral wall of the brick inner core and the ventilation layer, and the peripheral wall of the brick inner core is provided with an upper connecting column connected with the ventilation layer; the bottom of the outer layer of the brick is provided with an air guide hole which upwards penetrates through the outer layer of the brick and is communicated with the lower gas flow passage, the air guide hole is externally connected with a gas guide pipe, one end of the gas guide pipe is communicated with a gas joint, and the outer layer of the brick and the gas guide pipe are sleeved with steel sleeves; a fire clay layer is arranged between the outer layer of the brick and the steel sleeve sleeved outside the outer layer of the brick.

Furthermore, the ventilation layer is externally coated with an anti-oxidation high temperature resistant layer.

Further, the height of the steel sleeve on the outer layer of the outer casing brick is lower than that of the outer layer of the brick; the height difference between the steel sleeve on the outer layer of the outer sleeve brick and the outer layer of the brick is 10mm-40 mm.

Furthermore, the length of the upper connecting column is 0.8-1.5 mm; the length of the lower connecting column is 0.8-1.5 mm.

Furthermore, the steel sleeve comprises a first steel sleeve sleeved outside the brick outer layer, and a second steel sleeve sleeved outside the air guide pipe, and the second steel sleeve and the first steel sleeve are welded into a whole; the silver powder layer is covered on the outer sides of the second steel sleeve and the first steel sleeve.

Further, the air-permeable layer comprises 97 parts by weight of fused magnesia, 10-15 parts by weight of zirconium mullite, 5-15 parts by weight of fused quartz, 2-5 parts by weight of calcined alumina micro powder, 1-5 parts by weight of ferrosilicon nitride, 3-6 parts by weight of antioxidant, 5-8 parts by weight of ignition loss additive, 8-15 parts by weight of thermosetting liquid resin and 1-5 parts by weight of thermoplastic phenolic resin powder.

Furthermore, the fused magnesia comprises 20-30 parts of fused magnesia with the particle size of 3-5mm, 20-40 parts of fused magnesia with the particle size of 1-3mm and 20-40 parts of fused magnesia with the particle size of 0-1mm in parts by weight;

according to the parts by weight, the fused quartz comprises 3-10 parts of fused quartz with the particle size of 0.2-0.5mm and 2-10 parts of fused quartz with the particle size of 0-0.2 mm;

the particle size of the calcined alumina micro powder is 1 um;

the grain diameter of the zirconium mullite is 0.2-0.5 mm.

Further, the antioxidant is one or more of metal silicon powder, aluminum powder, silicon carbide or boron carbide in any combination; the ignition loss agent adopts one or two of dextrin or paraffin powder.

The invention also provides a preparation method of the air brick prepared based on the cold isostatic pressing wet bag method, which comprises the following steps:

respectively carrying out material mixing, drying and ageing on the brick inner core material mixing, the air-permeable layer material mixing and the brick outer layer material mixing to obtain a brick inner core material mixing to be used, an air-permeable layer material mixing to be used and a brick outer layer material mixing to be used;

putting the mixed material of the brick inner core into a one-step forming die, and carrying out isostatic pressing forming in a wet bag method isostatic pressing machine to obtain the brick inner core;

coating a wax sheet on the outer surface of the brick inner core, arranging a plurality of through holes penetrating the wax sheet on the wax sheet at intervals, putting the brick inner core coated with the wax sheet into a secondary forming die, adding a to-be-used air-permeable layer mixed material and a brick outer layer mixed material into corresponding positions of the secondary forming die, and performing isostatic pressing forming in a wet bag method isostatic press to obtain an air-permeable brick blank;

drilling a hole at the bottom of the air brick blank, extending the drilled hole to a wax sheet, placing for 8-12 hours, and roasting to obtain an air brick to be treated;

embedding an air guide pipe at a drill hole of the air brick to be processed, smearing fire clay on the surface of the outer layer of the air brick to be processed, and sleeving a steel sleeve on the outer layer of the brick and the air guide pipe; one end of the gas guide pipe is communicated with the gas connector to obtain the gas permeable brick.

Further, after the brick inner core mixed material is placed into a one-step forming die, when wet bag cold isostatic pressing is carried out, the wet bag cold isostatic pressing pressure is 15MPa-30 MPa;

placing the inner core of the brick wrapped with the wax sheet into a secondary forming die, and performing wet bag cold isostatic pressing, wherein the wet bag cold isostatic pressing pressure is 45-130 MPa;

spraying an anti-oxidation high-temperature-resistant coating on the outer surface of the air-permeable layer of the air-permeable brick;

the material of the anti-oxidation high-temperature-resistant coating is a magnesium carbon material or an aluminum-magnesium carbon material;

the steel sleeve comprises a first steel sleeve sleeved outside the outer layer of the brick and a second steel sleeve sleeved on the air guide pipe, the second steel sleeve is welded on the first steel sleeve, and silver powder is sprayed on the outer surfaces of the first steel sleeve and the second steel sleeve;

the water temperature of the wet bag method isostatic pressing machine is 25-30 ℃ when the wet bag method isostatic pressing machine works;

the thickness of a wax sheet wrapped outside the inner core of the brick is 0.5-0.8mm, the diameter of a through hole on the wax sheet is 8-10mm, and the through hole accounts for 28% of the area of the whole wax sheet;

the diameter of the air guide hole is 4-6 mm.

The outer layer material of the brick comprises at least one of a magnesia carbon material, an aluminum-magnesium spinel material or a corundum material;

the brick inner core material comprises at least one of a magnesium carbon material, an aluminum magnesium spinel material or a corundum material.

Compared with the prior art, the air brick prepared based on the cold isostatic pressing wet bag method and the preparation method thereof provided by the invention have the following progress:

1. according to the air brick prepared based on the cold isostatic pressing wet bag method, the steel sleeve is sleeved outside the air brick, when the air brick is installed at the bottom of the steel ladle, the air brick does not need to be embedded into the sitting brick, the problem of steel clamping between the air brick and the sitting brick can be effectively solved, and the accident risk caused by using too many elements for the steel ladle, such as the introduction of the sitting brick, is avoided.

2 when the air brick prepared based on the cold isostatic pressing wet bag method is used for cleaning cold steel on the surface of the air brick, oxygen is blown into the upper air flow channel through the air guide hole and the lower air flow channel, and the air brick is cleaned by adopting the oxygen, so that the technical problem that the inner core of the air brick is blown and lost by the oxygen due to the fact that the surface of the air brick is directly blown by the oxygen in the traditional mode is effectively solved.

Compared with the existing diffused type, slit type and straight-through hole type air brick, the air brick obtained by the invention has the advantages that the air holes are not easy to block, and the argon blowing effect is not influenced.

4. According to the preparation method of the air brick, when the air brick is formed by pressing the wet bag method isostatic pressing machine, the pressure applied to each part of the whole air brick is consistent, so that the problem that different parts are subjected to different pressures during forming of the air brick can be well solved; the air brick obtained by pressing the wet bag method isostatic pressing machine has high thermal shock stability, the air permeability is uniform, stable and sufficient, the floating of non-metallic inclusions in molten steel can be effectively promoted, the molten steel temperature and components in a steel ladle tend to be more uniform and stable, the cleanliness of the molten steel is improved, and the quality of a cast steel blank is improved.

Drawings

In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, and it is obvious that the drawings in the following description are some embodiments of the present invention, and other drawings can be obtained by those skilled in the art without creative efforts.

FIG. 1 is a schematic structural diagram (cross-sectional view) of an air brick prepared by a cold isostatic pressing wet bag method according to the invention;

FIG. 2 is a block diagram of the steps of the method for making the air brick of the present invention.

Description of reference numerals:

1. an outer layer of the brick; 2. an inner core of a brick; 101. a groove is embedded; 3. a lower gas flow channel; 4. a lower connecting column; 5. a breathable layer; 6. an upper gas flow path; 7. an upper connecting column; 8. an air vent; 9. an air duct; 10. steel jacket; 11. a gas joint; 12. a fireclay layer; 1001. a first steel jacket; 1002. a second steel jacket.

Detailed Description

The technical solutions of the present invention will be described clearly and completely with reference to the accompanying drawings, and it should be understood that the described embodiments are some, but not all embodiments of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

In the description of the present invention, it should be noted that the terms "center", "upper", "lower", "left", "right", "vertical", "horizontal", "inner", "outer", etc., indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, and are only for convenience of description and simplicity of description, but do not indicate or imply that the device or element being referred to must have a particular orientation, be constructed and operated in a particular orientation, and thus, should not be construed as limiting the present invention. Furthermore, the terms "first," "second," and "third" are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present invention, it should be noted that, unless otherwise explicitly specified or limited, the terms "mounted," "connected," and "connected" are to be construed broadly, e.g., as meaning either a fixed connection, a removable connection, or an integral connection; can be mechanically or electrically connected; they may be connected directly or indirectly through intervening media, or they may be interconnected between two elements. The specific meanings of the above terms in the present invention can be understood in specific cases to those skilled in the art.

As shown in figure 1, the invention provides an air brick prepared based on a cold isostatic pressing wet bag method, which comprises an outer brick layer 1, wherein an embedded groove 101 is arranged at the upper end of the outer brick layer 1, an inner brick core 2 is embedded in the embedded groove 101, a lower gas flow channel 3 is arranged between the peripheral wall of the inner brick core 2 and the inner wall of the embedded groove 101, and a plurality of lower connecting columns 4 connected with the outer brick layer 1 are arranged at intervals on the peripheral wall of the inner brick core 2; the upper end of the brick inner core 2 extends upwards to the outside of the embedded groove 101, the brick inner core 2 arranged outside the embedded groove 101 is wrapped with a ventilation layer 5, an upper gas flow passage 6 communicated with the lower gas flow passage 3 is arranged between the peripheral wall of the brick inner core 2 and the ventilation layer 5, and an upper connecting column 7 connected with the ventilation layer 5 is arranged on the peripheral wall of the brick inner core 2; the bottom of the brick outer layer 1 is provided with an air guide hole 8, the air guide hole 8 penetrates the brick outer layer 1 upwards to be communicated with the lower gas flow channel 3, the air guide hole 8 is externally connected with a gas guide pipe 9, one end of the gas guide pipe 9 is communicated with a gas connector 11, and both the brick outer layer 1 and the gas guide pipe 9 are externally sleeved with a steel sleeve 10; a fire clay layer 12 is arranged between the brick outer layer 1 and the steel sleeve 10 which is sleeved outside the brick outer layer 1.

Specifically, the air-permeable layer 5 is externally coated with an anti-oxidation high temperature resistant layer.

Specifically, the height of the steel jacket 10 of the outer layer 1 of the outer casing brick is lower than that of the outer layer 1 of the brick; the height difference between the steel sleeve of the outer layer 1 of the outer sleeve brick and the outer layer 1 of the brick is 10mm-40 mm.

Specifically, the length of the upper connecting column 7 is 0.8-1.5 mm; the length of the lower connecting column 4 is 0.8-1.5 mm.

Specifically, the steel jacket 10 comprises a first steel jacket 1001 externally sleeved on the brick outer layer 1, a second steel jacket 1002 externally sleeved on the air duct 9, and the second steel jacket 1002 and the first steel jacket 1001 are welded into a whole; a silver powder layer is coated outside the second steel sleeve 1002 and the first steel sleeve 1001.

Specifically, the air-permeable layer 5 comprises 97 parts by weight of fused magnesia, 10-15 parts by weight of zirconium mullite, 5-15 parts by weight of fused quartz, 2-5 parts by weight of calcined alumina micro powder, 1-5 parts by weight of ferrosilicon nitride, 3-6 parts by weight of antioxidant, 5-8 parts by weight of ignition loss additive, 8-15 parts by weight of thermosetting liquid resin and 1-5 parts by weight of thermoplastic phenolic resin powder.

Specifically, the fused magnesia comprises 20-30 parts by weight of fused magnesia with the particle size of 3-5mm, 20-40 parts by weight of fused magnesia with the particle size of 1-3mm and 20-40 parts by weight of fused magnesia with the particle size of 0-1 mm;

according to the parts by weight, the fused quartz comprises 3-10 parts of fused quartz with the particle size of 0.2-0.5mm and 2-10 parts of fused quartz with the particle size of 0-0.2 mm;

the particle size of the calcined alumina micro powder is 1 um;

the grain diameter of the zirconium mullite is 0.2-0.5 mm.

Specifically, the antioxidant is one or more of metal silicon powder, aluminum powder, silicon carbide or boron carbide in any combination; the ignition loss agent adopts one or two of dextrin or paraffin powder.

As shown in fig. 2, the invention further provides a method for preparing the air brick prepared by any one of the above methods based on the cold isostatic pressing wet bag method, which comprises the following steps:

s1) respectively carrying out material mixing, drying and ageing on the brick inner core material mixing, the air-permeable layer material mixing and the brick outer layer material mixing to obtain a brick inner core material mixing to be used, an air-permeable layer material mixing to be used and a brick outer layer material mixing to be used;

s2) putting the mixed materials of the brick inner core into a one-step forming die, and carrying out isostatic pressing forming in a wet bag method isostatic pressing machine to obtain a brick inner core 2;

s3) coating wax sheets on the outer surface of the brick inner core 2, arranging a plurality of through holes penetrating through the wax sheets at intervals on the wax sheets, putting the brick inner core 2 coated with the wax sheets into a secondary forming mould, adding a to-be-used air-permeable layer mixed material and a brick outer layer mixed material into the corresponding position of the secondary forming mould, and carrying out isostatic pressing forming in a wet bag method isostatic pressing machine to obtain an air-permeable brick blank; drilling a hole at the bottom of the air brick blank, extending the drilled hole to a wax sheet, placing for 8-12 hours, and roasting to obtain an air brick to be treated; embedding an air duct 9 at a drill hole of the air brick to be processed, smearing fire clay on the surface of the outer layer 1 of the air brick to be processed, and sleeving a steel sleeve 10 on the outer layer 1 of the brick and the air duct 9; one end of the gas-guide tube 9 is communicated with the gas connector 11 to obtain the gas permeable brick.

Specifically, after the brick inner core mixed material is put into a one-step forming die, when wet bag cold isostatic pressing is carried out, the wet bag cold isostatic pressing pressure is 15MPa-30 MPa;

placing the brick inner core 2 wrapped with the wax sheet into a secondary forming die, and performing wet bag cold isostatic pressing, wherein the wet bag cold isostatic pressing pressure is 45-130 MPa;

spraying an anti-oxidation high-temperature-resistant coating on the outer surface of the air-permeable layer 5 of the air-permeable brick;

the material of the anti-oxidation high-temperature-resistant coating is a magnesium carbon material or an aluminum-magnesium carbon material;

the steel sleeve 10 comprises a first steel sleeve 1001 sleeved outside the brick outer layer 1 and a second steel sleeve 1002 sleeved on the gas guide pipe 9, the second steel sleeve 1002 is welded on the first steel sleeve 1001, and silver powder is sprayed on the outer surfaces of the first steel sleeve 1001 and the second steel sleeve 1002;

the water temperature of the wet bag method isostatic pressing machine is 25-30 ℃ when the wet bag method isostatic pressing machine works;

the thickness of the wax sheet wrapped outside the brick inner core 2 is 0.5-0.8mm, the diameter of a through hole on the wax sheet is 8-10mm, and the through hole accounts for 28% of the area of the whole wax sheet;

the diameter of the air guide hole 8 is 4-6 mm;

the outer layer 1 of the brick comprises at least one of a magnesia carbon material, an aluminum-magnesium spinel material or a corundum material;

the brick inner core 2 comprises at least one of a magnesia carbon material, an aluminum-magnesium spinel material or a corundum material.

According to the air brick provided by the invention, the steel sleeve is sleeved outside the air brick, when the air brick is installed at the bottom of the ladle, the air brick does not need to be embedded into the sitting brick, the problem of steel clamping between the air brick and the sitting brick can be effectively solved, and the accident risk caused by using too many elements for the steel ladle, such as the introduction of the sitting brick, is avoided.

When the air brick is used for cleaning cold steel on the surface of the air brick, oxygen is blown into the upper gas flow channel 6 through the air guide holes 8 and the lower gas flow channel 3, and the air brick is cleaned by adopting the oxygen, so that the technical problem that the inner core of the air brick is blown and lost by the oxygen due to the fact that the surface of the air brick is directly blown by the oxygen in the traditional mode is effectively solved;

when the air brick is formed by pressing the wet bag method isostatic pressing machine, the pressure applied to each part of the whole air brick is consistent, so that the problem that different parts of the air brick are subjected to different pressures during forming can be solved well; the air brick obtained by pressing the wet bag method isostatic pressing machine has high thermal shock stability, the air permeability is uniform, stable and sufficient, the floating of non-metallic inclusions in molten steel can be effectively promoted, the molten steel temperature and components in a steel ladle tend to be more uniform and stable, the cleanliness of the molten steel is improved, and the quality of a cast steel blank is improved.

Compared with the existing diffusion type, slit type and straight-through hole type air brick, the air brick obtained by the invention has the advantages that the air holes are not easy to block, and the argon blowing effect is not influenced.