CN112552053A

CN112552053A - Silicon carbide refractory brick for coke dry quenching furnace and preparation method thereof

Info

Publication number: CN112552053A
Application number: CN202011447241.2A
Authority: CN
Inventors: 钟凯; 崔园园; 祝少军; 李东涛; 曹勇; 温太阳; 杨彬
Original assignee: Shougang Corp
Current assignee: Shougang Group Co Ltd; Shougang Corp
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2021-03-26

Abstract

The invention belongs to the technical field of refractory materials for chute areas of dry quenching furnaces, and particularly relates to a silicon carbide refractory brick for a dry quenching furnace and a preparation method thereof, wherein the refractory brick comprises the following raw materials in parts by weight: silicon carbide powder: 60-110 parts; metal silicon powder: 5-15 parts; silicon carbide fiber: 2-10 parts; a sintering aid: 0.5-2 parts; an improving agent: 1-4 parts; adhesive: 1-4 parts. The refractory brick provided by the invention has excellent comprehensive performance, the normal-temperature compressive strength is 204-211MPa, the high-temperature rupture strength is 29.7-30.5MPa, and the strength is high; the residual strength rate is 79-82%, and the thermal shock resistance is good; the abrasion loss is 2.8-3.2cm³The wear resistance is good; the service life is 12-15 years, and the fracture energy is 230‑245J·m^‑2The toughness is good; and the refractory brick has low production cost and is beneficial to popularization and application.

Description

Silicon carbide refractory brick for coke dry quenching furnace and preparation method thereof

Technical Field

The invention belongs to the technical field of refractory materials for a chute area of a dry quenching furnace, and particularly relates to a silicon carbide refractory brick for the dry quenching furnace and a preparation method thereof.

Background

The main equipment of dry quenching coke masonry belongs to a shaft kiln type structure, the positive pressure cylindrical upright masonry is surrounded by an iron shell, the inner layer is built by different refractory bricks, and the furnace body can be divided into a pre-storage chamber, a chute area and a cooling section from top to bottom. The refractory shaped product in the chute area is a brick masonry which is overhung layer by layer to support the load of the upper masonry, the depth of the air passage is changed layer by layer, the temperature at the position frequently fluctuates, the brick masonry is violently scoured by airflow and coke dust, and the brick masonry is influenced by combustion air entering the upper annular flue. Therefore, the brickwork of the refractory bricks in the chute area bears the action of a great mechanical load, and the load generates corresponding tensile stress and compressive stress on the refractory bricks at different parts, so that the refractory materials in the chute area are required to have enough compression strength and high-temperature rupture strength; because the refractory bricks in the chute area have large temperature fluctuation along the chute direction, the refractory bricks are subjected to large thermal shock damage, so the material in the area has high thermal shock stability; the brick body is easy to wear and destroy due to the violent scouring of air flow and coke dust, so that the material has excellent wear resistance; the recycle gas contains, in addition to inert gases, reducing gases (CO, H2), and small amounts of oxidizing gases (O)₂、H₂O) and the alkaline substances on the coke surface also chemically attack the firebricks, so the refractory material for the chute must also have good chemical stability and excellent oxidation and CO gas corrosion resistance.

The traditional refractory materials for the chute area mainly comprise mullite-andalusite bricks, andalusite-silicon carbide bricks and other refractory materials mainly containing aluminum and silicon, but the refractory materials can crack and break after being used for two or three years. In recent years, nitride-bonded silicon carbide bricks are used for corbels in the chute area of a dry quenching furnace, and the bricks have high normal-temperature pressure resistance and high-temperature rupture strength, but the refractory materials also have the defects of high hardness, high brittleness and low toughness, and once cracks appear under mechanical stress or thermal stress, the cracks are rapidly expanded until the bricks are completely broken, so that the service life is influenced.

Disclosure of Invention

In order to solve the problems, the invention provides a silicon carbide refractory brick for a dry quenching furnace and a preparation method thereof, so as to provide a refractory material with good comprehensive performance applied to a chute area of the dry quenching furnace.

On one hand, the invention provides a silicon carbide refractory brick for a dry quenching furnace, and the raw materials of the refractory brick comprise the following components in parts by weight:

silicon carbide powder: 60-110 parts;

metal silicon powder: 5-15 parts;

silicon carbide fiber: 2-10 parts;

a sintering aid: 0.5-2 parts;

an improving agent: 1-4 parts;

adhesive: 1-4 parts.

Furthermore, in the silicon carbide fiber, the mass fraction of SiC is more than or equal to 98%, and the length of the silicon carbide fiber is 0.5-5 mm.

Furthermore, the granularity of the silicon carbide is less than or equal to 3mm, in the silicon carbide powder, the mass fraction of the granularity which is more than 1mm and less than or equal to 3mm is 30-55%, the mass fraction of the granularity which is more than 0.074mm and less than or equal to 1mm is 20-40%, and the mass fraction of the granularity which is less than or equal to 0.074mm is 20-35%; in the silicon carbide, the mass fraction of SiC is more than or equal to 90%.

Furthermore, the particle size of the metal silicon powder is less than or equal to 0.074mm, and the mass fraction of Si in the metal silicon powder is more than or equal to 98%.

Furthermore, the particle size of the metal silicon powder is less than or equal to 0.044 mm.

Further, the binder is carboxymethyl cellulose or polyvinyl alcohol.

Further, the material also comprises 3-5% of water in parts by weight.

Further, the sintering aid is at least one of the following: yttrium oxide, lanthanum oxide, cerium oxide.

Further, the improving agent is at least one of: perlite powder and refractory clay.

In another aspect, the invention also provides a preparation method of the silicon carbide refractory brick for the coke dry quenching furnace, which comprises the following steps,

mixing and stirring silicon carbide powder, metal silicon powder and silicon carbide fiber for 5-8min according to the weight parts to obtain a first mixture;

adding the sintering aid, the improver, the binder and water into a small-sized stirrer according to the parts by weight, mixing and stirring for 3-5min to obtain a second mixture;

mixing the first mixture and the second mixture, ageing for 32-48 hours, drying, and firing at 1300-1500 ℃ in nitrogen atmosphere to obtain the silicon carbide refractory brick.

One or more technical solutions in the embodiments of the present invention have at least the following technical effects or advantages:

the invention provides a silicon carbide refractory brick for a coke dry quenching furnace and a preparation method thereof, wherein silicon carbide powder is used as a framework of the refractory brick raw material and is matched with silicon carbide fibers in a specific weight part, so that the refractory brick has high strength, high thermal shock resistance and wear resistance, and has good toughness and prolonged service life. The addition of the metal silicon powder can prevent the silicon carbide powder from being oxidized, and the addition of the sintering aid and the binder can improve the compactness of the silicon carbide powder in the sintering process and improve the strength of the refractory brick, so that the refractory brick has excellent comprehensive performance. The refractory brick prepared by the embodiment of the invention has the normal temperature compressive strength of 204-211MPa, the high temperature rupture strength of 29.7-30.5MPa and high strength; the residual strength rate is 79-82%, and the thermal shock resistance is good; the abrasion loss is 2.8-3.2cm³The wear resistance is good; the service life is 12-15 years, and the fracture energy is 230-245 J.m^-2The toughness is good; and the refractory brick has low production cost and is beneficial to popularization and application.

Detailed Description

The present invention will be described in detail below with reference to specific embodiments and examples, and the advantages and various effects of the present invention will be more clearly apparent therefrom. It will be understood by those skilled in the art that these specific embodiments and examples are provided to illustrate the invention, and not to limit the invention.

Throughout the specification, unless otherwise specifically noted, terms used herein should be understood as having meanings as commonly used in the art. Accordingly, unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. If there is a conflict, the present specification will control.

Unless otherwise specifically stated, various raw materials, reagents, instruments, equipment and the like used in the present invention are commercially available or can be prepared by an existing method.

In order to solve the technical problems, the embodiment of the invention provides the following general ideas:

the embodiment of the invention provides a silicon carbide refractory brick for a coke dry quenching furnace, which comprises the following raw materials in parts by weight:

60-110 parts of silicon carbide powder;

5-15 parts of metal silicon powder;

silicon carbide fiber: 2-10 parts;

a sintering aid: 0.5-2 parts;

an improving agent: 1-4 parts;

adhesive: 1-4 parts.

The functions of the components are as follows:

silicon carbide powder: mainly used as aggregate and partial matrix, so that the refractory brick has high strength, high thermal shock resistance, excellent wear resistance, high thermal conductivity and chemical corrosion resistance in a wider temperature range.

Metal silicon powder: silicon nitride or oxynitride is generated during the nitriding process to prevent oxidation of silicon carbide.

Silicon carbide fiber: the high-strength high-modulus high-strength high-toughness composite material has the characteristics of high strength and high modulus, can share most of external stress for a matrix, can also block the expansion of cracks, can consume part of energy in the form of 'pulling-out work' when local fibers are fractured, has the effects of improving the fracture energy and overcoming the brittleness, and absorbs energy through mechanisms such as fiber fracture and pulling-out, crack deflection and the like in the fracture process, so that the strength and the toughness of the material are improved, and the excellent high-temperature performance of the material is also kept; in addition, in the reactive sintering process of the silicon carbide, the silicon carbide fiber has good thermal stability, and can overcome the thermal corrosion influence caused by the heat released by the carbon-silicon reaction.

A sintering aid: the silicon carbide crystal of the silicon carbide powder has strong covalent bonds, and sintering densification is difficult to realize even at high temperature; meanwhile, the silicon carbide crystal has higher crystal lattice interface energy, and the particles are difficult to obtain enough energy to form a new crystal boundary during sintering. In addition, a dense oxide film is easily formed on the surface of the silicon carbide particles, and the particles are prevented from migrating and growing during sintering. The sintering aid can enable the silicon carbide powder to be sintered more densely.

An improving agent: the sintering temperature is reduced, and meanwhile, the wettability of a liquid phase in the sintering process is improved, so that the liquid phase has certain dissolving capacity on a solid phase, the sintering process is improved, and the manufacturing cost is reduced.

Adhesive: the silicon carbide powder has good wettability to refractory aggregate silicon carbide powder, can reduce the friction force among different particles of the silicon carbide powder, can be mixed and formed at normal temperature, has good viscosity and high green body strength, and thus improves the density and strength of finished products.

According to the invention, silicon carbide powder is used as a framework and is matched with silicon carbide fibers in a specific weight part, so that the refractory brick has high strength, high thermal shock resistance and wear resistance, and has good toughness, and the service life of the refractory brick is prolonged. The addition of the metal silicon powder can prevent the silicon carbide powder from being oxidized, and the addition of the sintering aid and the binder can improve the compactness of the silicon carbide powder in the sintering process and improve the strength of the refractory brick.

As an implementation mode of the embodiment of the invention, in the silicon carbide fiber, the mass fraction of SiC is more than or equal to 98%, and the length of the silicon carbide fiber is 0.5-5 mm. Too long a length of the silicon carbide fiber may affect the compactness of the refractory brick, thereby reducing the strength of the refractory brick.

As an implementation mode of the embodiment of the invention, the granularity of the silicon carbide is less than or equal to 3mm, in the silicon carbide powder, the mass fraction of the silicon carbide powder with the granularity of more than 1mm and less than or equal to 3mm is 30-55%, the mass fraction of the silicon carbide powder with the granularity of more than 0.074mm and less than or equal to 1mm is 20-40%, and the mass fraction of the silicon carbide powder with the granularity of less than or equal to 0.074mm is 20-35%; in the silicon carbide, the mass fraction of SiC is more than or equal to 90%. The silicon carbide powder with different particle size distributions can be matched to improve the compactness of the refractory raw material by closely stacking the refractory raw material, so that the strength of the refractory brick is improved.

As an implementation manner of the embodiment of the invention, the particle size of the metal silicon powder is less than or equal to 0.074mm, and the mass fraction of Si in the metal silicon powder is more than or equal to 98%. The particle size of the silicon powder is controlled to enable the raw materials of the refractory bricks to be tightly stacked, so that the compactness is improved, and the refractory bricks have good strength.

As an implementation manner of the embodiment of the invention, the particle size of the metal silicon powder is less than or equal to 0.044 mm.

As an implementation of the embodiments of the present invention, the binder is carboxymethyl cellulose or polyvinyl alcohol.

In one embodiment of the invention, the raw material of the refractory brick further comprises 3-5 wt% of water.

As an implementation manner of the embodiment of the present invention, the sintering aid is at least one of the following: yttrium oxide, lanthanum oxide, cerium oxide. The rare earth oxide generates high-temperature eutectic melt during heating, which is beneficial to the sintering process of the material, and the rare earth element plays a role in active catalysis, so that the nitridation reaction is easier to perform, and the manufacturing cost is reduced.

As an embodiment of the present invention, the improving agent is at least one of: perlite powder and refractory clay.

On the other hand, the embodiment of the invention also provides a preparation method of the silicon carbide refractory brick for the coke dry quenching furnace, which comprises the following steps,

s1, mixing and stirring silicon carbide powder, metal silicon powder and silicon carbide fibers for 5-8min according to the weight parts to obtain a first mixture;

s2, adding the sintering aid, the improver, the binder and the water in parts by weight, mixing and stirring for 3-5min to obtain a second mixture;

s3, mixing the first mixture and the second mixture, ageing for 32-48 hours, drying, and firing at 1300-1500 ℃ in nitrogen atmosphere to obtain the silicon carbide refractory brick.

In step S3, stirring may be performed for 5-15min after mixing. The stirring can be performed in a planetary mixer. After the ageing of the first mixture and the second mixture is finished, the first mixture and the second mixture can be pressed into green bricks by a high-frequency vibration press under the pressure of 50-150MPa, and then the green bricks are dried at 110 ℃ for 48 hours and then are fired, wherein the firing time can be 72-96 hours.

The mixing uniformity of the raw materials can be improved by adopting a planetary mixer for stirring and adopting a high-frequency vibration press for molding, and the density of the green brick is improved.

The firing may be performed in a nitriding kiln, and the metal silicon powder may be fired in a nitrogen atmosphere to form silicon nitride or silicon oxynitride, which adheres to the silicon oxide film on the surface of the silicon carbide powder and reacts therewith to form a continuous protective film that is firmly bonded to the silicon carbide to protect the silicon carbide from oxidation.

The silicon carbide refractory brick for a coke dry quenching furnace and the preparation method thereof according to the present invention will be described in detail with reference to examples, comparative examples and experimental data.

Example 1

Example 1 provides a silicon carbide refractory brick, which comprises the following raw materials in percentage by weight:

85% of silicon carbide powder, wherein the particle size of the silicon carbide powder is greater than 1mm and less than or equal to 3mm 47.05%, the particle size of the silicon carbide powder is greater than 0.2mm and less than or equal to 1mm 29.42%, and the particle size of the silicon carbide powder is less than or equal to 0.044mm 23.53%;

10 percent of metal silicon powder with the granularity less than or equal to 0.044 mm;

3% of silicon carbide fiber with the length of 0.5-5 mm;

0.5 percent of yttrium oxide with the grain size less than or equal to 0.044 mm;

1.5 percent of perlite powder.

The sum of the weight percentages of the raw materials is 100 percent.

And carboxymethyl cellulose accounting for 3 percent of the total weight of the raw materials, polyvinyl alcohol accounting for 2 percent of the total weight of the raw materials and water accounting for 5 percent of the total weight of the raw materials are added to be used as a bonding agent.

(1) Mixing the silicon carbide powder, the metal silicon powder and the silicon carbide fiber in the ratio in a planetary mixer and stirring for 6 min;

(2) adding the yttrium oxide, the perlite powder, the carboxymethyl cellulose, the polyvinyl alcohol and the water in the ratio into a small-sized stirrer, and stirring for 4 min; the obtained material was mixed with a planetary mixer and stirred for 15 min.

(3) Ageing the mixture obtained by stirring for 48 hours; pressing the materials into green bricks by a high-frequency vibration press under the pressure of 100MPa, drying the green bricks for 48 hours at the temperature of 110 ℃, and finally firing the obtained green bricks for 72 hours at the temperature of 1400 ℃ in a nitriding kiln to obtain the silicon carbide refractory bricks.

Example 2

Embodiment 2 provides a silicon carbide refractory brick, which comprises the following raw materials in percentage by weight:

81 percent of silicon carbide powder, wherein the particle size of the silicon carbide powder is more than 1mm and less than or equal to 3mm and is 52.94 percent, the particle size of the silicon carbide powder is more than 0.2mm and less than or equal to 1mm and is 23.53 percent, and the particle size of the silicon carbide powder is less than or equal to 0.044mm and is 23.53 percent;

6% of silicon carbide fiber with the length of 0.5-5 mm;

1% of lanthanum oxide with the granularity less than or equal to 0.044 mm;

2 percent of refractory clay.

The sum of the weight percentages of the raw materials is 100 percent.

And carboxymethyl cellulose accounting for 2 percent of the total weight of the raw materials, polyvinyl alcohol accounting for 2 percent of the total weight of the raw materials and water accounting for 4 percent of the total weight of the raw materials are added to be used as a bonding agent.

(1) Mixing the silicon carbide powder, the metal silicon powder and the silicon carbide short fibers in the ratio for 5min in a planetary stirrer;

(2) adding the lanthanum oxide, the refractory clay, the carboxymethyl cellulose, the polyvinyl alcohol and the water in the proportion into a small-sized stirrer, and stirring for 5 min; the obtained material was mixed with a planetary mixer and stirred for 20 min.

(3) Ageing the mixture obtained by stirring for 35 hours; pressing the materials into green bricks by a high-frequency vibration press under the pressure of 120MPa, and drying the green bricks for 48 hours at the temperature of 110 ℃. Finally, the obtained green brick is fired for 72 hours in a nitriding kiln at 1420 ℃ to obtain the fiber reinforced silicon nitride combined silicon carbide refractory brick.

Example 3

Example 3 provides a silicon carbide refractory brick, which comprises the following raw materials in percentage by weight:

silicon carbide powder: 84 percent, wherein the granularity of the silicon carbide powder is more than 1mm and less than or equal to 40 percent of the silicon carbide powder with the granularity of less than or equal to 3mm, the granularity of more than 0.2mm and less than or equal to 30 percent of the silicon carbide powder with the granularity of less than or equal to 1mm, and the granularity of less than or equal to 30 percent of the silicon carbide powder with the granularity of less;

8 percent of metal silicon powder with the granularity less than or equal to 0.044 mm;

4% of silicon carbide fiber with the length of 0.5-5 mm;

3 percent of cerium oxide with the granularity less than or equal to 0.044 mm;

3% of refractory clay.

The sum of the weight percentages of the raw materials is 100 percent.

(2) adding the cerium oxide, the chamotte, the carboxymethyl cellulose, the polyvinyl alcohol and the water in the ratio into a small-sized stirrer, and stirring for 5 min; the obtained material was mixed with a planetary mixer and stirred for 20 min.

(3) Ageing the mixture obtained by stirring for 38 hours; pressing the materials into green bricks by a high-frequency vibration press under the pressure of 120MPa, and drying the green bricks for 48 hours at the temperature of 110 ℃. Finally, the obtained green brick is fired for 72 hours in a nitriding kiln at 1350 ℃ to obtain the fiber-reinforced silicon nitride-silicon carbide combined refractory brick.

Example 4

Example 4 provides a silicon carbide refractory brick, which comprises the following raw materials in percentage by weight:

silicon carbide powder: 81 percent, wherein 45 percent of silicon carbide powder with the granularity of more than 1mm and less than or equal to 3mm, 35 percent of silicon carbide powder with the granularity of more than 0.2mm and less than or equal to 1mm, and 20t percent of silicon carbide powder with the granularity of less than or equal to 0.044 mm;

6 percent of metal silicon powder with the granularity less than or equal to 0.044 mm;

10% of silicon carbide fiber with the length of 0.5-5 mm;

1 percent of mixture of lanthanum oxide and cerium oxide with the granularity less than or equal to 0.044 mm;

2 percent of refractory clay.

The sum of the weight percentages of the raw materials is 100 percent.

(3) Ageing the mixture obtained by stirring for 46 hours; pressing the materials into green bricks by a high-frequency vibration press under the pressure of 120MPa, and drying the green bricks for 48 hours at the temperature of 110 ℃. Finally, the obtained adobe is fired for 72 hours in a nitriding kiln at 1450 ℃, and the fiber-reinforced silicon nitride-silicon carbide combined refractory brick is obtained.

Comparative example 1

Comparative example 1 provides a silicon carbide refractory brick whose raw material consists of the following components in percentage by weight,

70% of silicon carbide sand, 10% of industrial silicon, 5% of silicon dioxide micropowder, 10% of silicon nitride, 0.5% of magnesium oxide, 2% of zirconium oxide, 2% of binding agent and sintering aid.

Firstly, mixing the industrial silicon, the superfine silicon dioxide powder, the silicon nitride, the magnesia, the zirconia and the sintering aid in percentage by weight; then the carborundum sand and the bonding agent are put into a stirrer to be stirred, the materials mixed previously are added into the stirrer to be continuously stirred, the obtained mixed materials are pressed into green bricks after discharging, and the green bricks are sent into an industrial kiln to be heated and baked for more than 72 hours and cooled along with the kiln; firing the obtained green brick under the protection of nitrogen atmosphere; cooling to room temperature after sintering, and taking out the kiln.

Comparative example 2

Comparative example 2 provides an alumina-silica refractory brick, currently used as a dry quenching oven corbel part, made from the following composition in weight percent, molel M60: 5 to 15 percent; m47: 30-50%; 10-20% of andalusite; 30 to 40 percent of fine powder,

adding liquid paper pulp and alumina micropowder into the mullite M60, andalusite and fine powder in percentage by weight, carrying out mechanical pressing molding, and firing at 1500 ℃.

The refractory bricks of examples 1 to 4 and comparative examples 1 to 2 were subjected to measurement of bulk density, apparent porosity, high-temperature rupture strength, normal-temperature compressive strength, residual strength ratio, wear amount and fracture energy, and the results are shown in Table 1.

TABLE 1

In the context of table 1, the following,

the apparent porosity is the ratio of the volume of all open pores in the refractory brick to the total volume of the open pores, and the higher the apparent porosity is, the poorer the compactness of the refractory material is, but the better the heat preservation performance is.

The high-temperature rupture strength means that the strip-shaped refractory brick sample is heated to the test temperature of 1100 ℃, the temperature is kept for 0.5h, stress is applied to the middle part of the sample at a constant loading rate until the sample is broken, and the maximum stress value is measured. The higher the high temperature rupture strength, the better the strength performance of the refractory brick at high temperature.

The residual strength rate is the ratio of the normal-temperature breaking strength and the original normal-temperature breaking strength of the refractory brick after the refractory brick is subjected to 20 times of thermal shock impact, and the higher the residual strength rate is, the better the thermal shock resistance of the refractory brick is.

The abrasion loss was measured by vertically spraying 1kg of silicon carbide sand onto the flat surface of a refractory brick sample through a sand blast pipe with compressed air of 450kPa to measure the volume of the refractory brick sample abraded. The smaller the wear, the better the wear resistance of the refractory brick.

The fracture energy is the energy per projected area required to create two new surfaces inside the ceramic material from a crack. Thus, it is believed that the higher the fracture energy of the material, the better its "toughness". The reason is that the propagation of cracks in such materials is difficult.

As can be seen from table 1, it is,

examples 1 to 4 provide refractory bricks having a bulk density of 2.77 to 2.82g cm^-3The apparent porosity is 11.9-12.5%, the normal temperature compressive strength is 204-211MPa, the high temperature rupture strength is 29.7-30.5MPa, the residual strength is 79-82%, and the abrasion loss is 2.8-3.2cm³The service life is 12-15 years, and the fracture energy is 230-245 J.m^-2。

The refractory brick provided by the comparative example 1 adopts a mode of combining silicon nitride with silicon carbide, has high strength, 202MPa of normal-temperature compressive strength and 25.4MPa of high-temperature rupture strength, but has the residual strength rate of only 45 percent after about 20 thermal shock impact, low toughness, more cracks on the surface, rapid crack propagation and easy brick falling, so the service life is only 5-8 years, and the fracture energy is 95 J.m^-2Not high, toughness is poor.

Comparative example 2 provides a refractory brick having a room-temperature compressive strength of 134MPa and a high-temperature flexural strength of 13.6MPa, and therefore, the amount of wear of the alumina-silica was 6.9cm³The wear resistance is poor, the service life is short, and is 5-10 years; because a certain amount of microcracks are formed in the firing process of the brick, the thermal shock resistance of the product is improved, and the residual strength rate after 20 times of thermal shock impact can reach 67 percent.

Compared with the comparative example 2, the refractory bricks of the embodiments 1 to 4 of the invention have the advantages that the normal temperature compressive strength and the high temperature rupture strength are improved by nearly one time, the thermal shock resistance is improved, the residual strength rate is obviously improved, the abrasion loss is reduced by more than 50 percent, and the service life is greatly prolonged, the maintenance time is saved, the production cost is reduced, and the normal stable production and the operation rate are improved for the dry quenching furnace.

The refractory brick provided by the embodiment of the invention is suitable for preparing large-size and complex-shape components, has the advantages of net size forming, high density, low sintering temperature, extremely short heat preservation time and the like, and has the normal-temperature compressive strength of 204-211MPa, the high-temperature rupture strength of 29.7-30.5MPa and high strength; the residual strength rate is 79-82%, and the thermal shock resistance is good; the abrasion loss is 2.8-3.2cm³The wear resistance is good; the service life is 12-15 years, and the fracture energy is 230-245 J.m^-2The toughness is good; and the refractory brick has low production cost and is beneficial to popularization and application.

Finally, it should also be noted that the terms "comprises," "comprising," or any other variation thereof, are intended to cover a non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements does not include only those elements but may include other elements not expressly listed or inherent to such process, method, article, or apparatus.

While preferred embodiments of the present invention have been described, additional variations and modifications in those embodiments may occur to those skilled in the art once they learn of the basic inventive concepts. Therefore, it is intended that the appended claims be interpreted as including preferred embodiments and all such alterations and modifications as fall within the scope of the invention.

It will be apparent to those skilled in the art that various changes and modifications may be made in the present invention without departing from the spirit and scope of the invention. Thus, if such modifications and variations of the present invention fall within the scope of the claims of the present invention and their equivalents, the present invention is also intended to include such modifications and variations.

Claims

1. The silicon carbide refractory brick for the coke dry quenching furnace is characterized by comprising the following raw materials in parts by weight:

silicon carbide powder: 60-110 parts;

metal silicon powder: 5-15 parts;

silicon carbide fiber: 2-10 parts;

a sintering aid: 0.5-2 parts;

an improving agent: 1-4 parts;

adhesive: 1-4 parts.

2. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the mass fraction of SiC in the silicon carbide fiber is not less than 98%, and the length of the silicon carbide fiber is 0.5-5 mm.

3. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the silicon carbide has a grain size of 3mm or less, and the silicon carbide powder has a mass fraction of 30-55% for a grain size of 1mm < 3mm, 20-40% for a grain size of 0.074mm < 1mm, and 20-35% for a grain size of 0.074 mm; in the silicon carbide, the mass fraction of SiC is more than or equal to 90%.

4. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the particle size of the metal silicon powder is less than or equal to 0.074mm, and the mass fraction of Si in the metal silicon powder is more than or equal to 98%.

5. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 3, wherein the particle size of the silicon metal powder is less than or equal to 0.044 mm.

6. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the binder is carboxymethyl cellulose or polyvinyl alcohol.

7. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the raw material of the refractory brick further comprises 3-5% by weight of water.

8. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the sintering aid is at least one of: yttrium oxide, lanthanum oxide, cerium oxide.

9. The silicon carbide refractory brick for the coke dry quenching furnace as claimed in claim 1, wherein the modifier is at least one of: perlite powder and refractory clay.

10. The method for preparing the silicon carbide refractory brick for the coke dry quenching furnace according to any one of claims 1 to 9, wherein the method comprises,

adding the sintering aid, the improver, the binder and water in parts by weight, mixing and stirring for 3-5min to obtain a second mixture;