JP2748328B2 - Glaze for hot application to coke oven refractories and method of forming glaze layer - Google Patents

Description

Description Technical Field [0001] The present invention is applied to a wall of a coke oven, such as bricks, irregular refractories, joints, etc., which are hot-worked to protect the wall and to produce tar during coal carbonization. The present invention relates to a glaze for forming a glaze layer on the surface thereof for preventing the carbon generated from carbon from adhering thereto and a method for forming a glaze layer on the inner wall surface of a coke oven.

BACKGROUND ART A coke oven produces carbon and coke by carbonizing coal, and at the same time, collects generated gas and tar. Some of the gas, tar, and the like during coal carbonization are decomposed by high temperatures in the coke oven to generate carbon. This carbon firmly adheres to the furnace wall of the coke oven and grows. In addition, coke ovens cause troubles such as being damaged by prolonged use. For this reason, the surface of the furnace refractory is coated with a denser layer to prevent carbon adhesion,
Alternatively, it becomes necessary to bury a refractory material in the damaged portion and repair it.

In a small furnace, in such a case, it is easy to shut down the furnace and take appropriate measures, but in the case of a large furnace such as a coke oven, it is often operated continuously for a long time, and the furnace is not cooled In many cases, it is necessary to take measures hot.

As a method for hot-coating the surface of the refractory of the furnace, there are methods such as spraying of an amorphous refractory, or plasma or arc spraying. The former method is a relatively inexpensive method, but has disadvantages in that it is difficult to form a dense coat layer, and the coat layer is not strong enough to be easily peeled. The latter method can form a film having relatively high strength, but has the drawback that the construction cost is high and the economic efficiency is disadvantageous.

A coke oven produces coke by steaming coal at about 1100 ° C for 20-25 hours. Tar-like substances and hydrocarbon gases are generated during the coal distillation process. These penetrate into gaps such as the inner wall of the coke oven, the furnace lid, and the coal inlet, and into the open pores of the refractory of the furnace body, and undergo pyrolytic carbonization to form strong carbon deposits.

This carbon deposit lowers the melting point of the refractory and causes embrittlement of the refractory. In addition, the carbon fouling deposits make it difficult to open and close the furnace lid, and deteriorate the hermetic sealing of the furnace lid to the coke oven. For this reason, the adhered carbon is also mechanically removed, but since the adherence is strong, the removing operation takes time and the working environment is poor. Further, during the removal operation, the surface of the refractory itself may be scraped off. As another method, burning is performed by blowing air or oxygen gas, but in this method, the working range is limited to the vicinity of the furnace port. In order to clean the entire area of the furnace, the furnace operation must be interrupted and the furnace must be emptied and burned down. However, the burning-off operation itself is a severe high-temperature operation, and the combustion heat at the time of burning-out brings a local high-temperature condition to the refractory of the furnace body, which may cause damage to the furnace body.

In order to cope with such a situation, various studies have been made on a refractory to which carbon is unlikely to adhere and a method of protecting the surface of the refractory by coating with a coating film.

For example, JP-B-62-19477: A composition comprising silicon carbide, silicon nitride or graphite particles and an inorganic binder is applied to a lining brick in a coke oven.

JP-A-62-197371: a heat-resistant and tar-based substance permeation preventive agent composed of silicon carbide, silicon nitride and the like, a binder composed of phosphate, yttrium oxide and the like, and a heat-insulating agent composed of potassium titanate fiber Is applied to the inner wall surface of the coke oven.

JP-B-63-40463: Graphite powder and an inorganic binder such as colloidal silica and alumina sol are applied to a refractory lining for a coke oven door.

Japanese Patent Application Laid-Open No. 63-267883: Simultaneously firing a glaze and a brick to produce a coke oven refractory brick having a glaze layer formed thereon.

Among the above methods, the method using silicon carbide, silicon nitride, graphite, or the like, has a problem that the affinity of these particles and the binder is poor, the adhesion strength is insufficient, and the coating layer peels off during operation. There is.

The method using a brick on which a glaze layer is formed has good adhesion and does not fall off during operation. Also, since there are almost no pores in the glaze layer coating, carbon is not penetrated and this is a very effective method. However, this method can be applied when newly manufacturing a coke oven or a furnace lid, but it is impossible to form a glaze layer on the surface of the refractory of the furnace while operating the furnace while hot. .

The present invention has been made in view of the above problems, and a first object of the present invention is to provide a glaze that can be hot-worked in a coke oven. The second object of the present invention is to provide a method for hot-applied to a joint or a surface of an amorphous refractory to prevent adhesion of carbon or to form a glaze layer which can be easily peeled off even if carbon adheres. Aim.

DISCLOSURE OF THE INVENTION The present invention consists of a combination of specific metal oxides, and when applied to the inner wall of a furnace, once melts and forms a glaze layer at a temperature near or below the actual furnace temperature of the furnace, The main point is a glaze whose melting point gradually rises and maintains the glaze layer.

After the glaze layer is formed by welding on the surface of the refractory inside the furnace, it does not melt or soften in the operating state of the furnace, so a strong glaze layer is formed.
Alternatively, even if they adhere, they can be easily peeled off, so that the above object can be achieved.

The present invention is a composition for forming a glaze, on an oxide basis, Li ₂ O is 0 to 10 wt%, B ₂ O ₃ is 0-10 wt%, R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
A glaze for hot application to coke oven refractories or a coke oven refractory for preventing carbon adhesion, characterized by containing O _{2 and} having a melting point of 900 ° C or less. is there.

The present invention also provides a composition for forming a glaze, on an oxide basis, Li ₂ O is 0 to 10 wt%, B ₂ O ₃ is 0-10 wt%, R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
It is characterized by adding 100 parts by weight or less of a thermal expansion coefficient adjusting agent to 100 parts by weight of glaze containing O _{2 and} having a melting point of 900 ° C. or less.

In the present invention, the thermal expansion coefficient adjusting agent is Al ₂ O ₃ , MgO, CaO, Z
It is selected from the group consisting of rO ₂ and TiO ₂ .

The present invention is characterized in that it comprises a Li ₂ O 0.2 to 10 wt%.

Further, the present invention is characterized in that B ₂ O ₃ is contained in an amount of 0.5 to 10% by weight.

Further, the present invention is characterized in that the compound forming SiO ₂ comprises at least one selected from the group consisting of sodium silicate, potassium silicate and lithium silicate, and an alkali siliconate.

The present invention also relates to the present invention, wherein the alkali siliconate is sodium methylsiliconate and 2% by weight to 30% by weight based on CH ₃ SiO _1.5.
% By weight.

The invention is also characterized in that the refractory of the coke oven is selected from the group consisting of bricks, joints and irregular refractories.

The present invention also provides a composition for forming a glaze, in terms of oxide, Li ₂ O is 0 to 10 wt%, B ₂ O ₃ is 0-10 wt%, R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
This is a method for forming a glaze layer, characterized by hot-working a glaze containing O _{2 and} having a melting point of 900 ° C. or less on the inner wall of the coke oven to form a glaze layer by welding.

The present inventors tested the possibility of using various metal oxide combinations as glazes, and focused on the melting behavior at high temperatures (near the actual furnace temperature of a coke oven etc.), and found the optimal combination. Thus, the present invention was found, and an improved composition was found from the viewpoint of the coefficient of thermal expansion, and an effective application of glaze to the inner wall of the furnace was enabled, thereby completing the present invention.

 Hereinafter, the present invention will be described in more detail.

In the present specification, the “glaze” may refer to a baked glaze, or may refer to a composition for glaze before application (a so-called premix). In the case of glaze, the above-mentioned oxide is contained as a component in a defined range. In the case of a glaze composition, the composition is a composition adjusted to include the above-mentioned oxide as a composition of a glaze that forms a glaze layer after application. Therefore, the glaze composition only needs to contain a metal salt or a metal compound which is converted into an oxide after the application, and it is not necessary to include the oxide before the application.

In any case, the glaze is characterized by containing R ₂ O (Na ₂ O or K ₂ O) and SiO ₂ as basic components, which are mixed with Li ₂ O and / or B ₂ O ₃ Preferably.

R ₂ O means either Na ₂ O or K ₂ O or a mixture of both.

Suitable precursors that are converted to the oxides include hydroxides, carbonates, nitrates, phosphates, sulfates, chlorides, and the like of the same metal. Precursor after application, preferably about 60
Any material that can be converted to an oxide at a temperature of 0 ° C. or higher may be used.

As precursors of Li ₂ O, lithium hydroxide, lithium carbonate, lithium hydrogen carbonate, lithium nitrate, lithium phosphate,
Preferred are lithium sulfate, lithium chloride, lithium silicate and the like.

As a precursor of Na ₂ O, sodium hydroxide, sodium carbonate, sodium hydrogencarbonate, sodium nitrate, sodium phosphate, sodium sulfate, sodium chloride, sodium silicate and the like are preferable.

As the precursor of K ₂ O, potassium hydroxide, potassium carbonate, potassium hydrogen carbonate, potassium nitrate, potassium phosphate,
Potassium sulfate, potassium chloride, potassium silicate and the like are preferred.

As precursors of B ₂ O ₃ , boric acid, sodium borate,
Potassium borate and the like are preferred.

As the precursor of SiO ₂ , sodium silicate, potassium silicate, lithium silicate, silica sol and water-soluble alkali methyl siliconate are preferred.

Examples of the alkali siliconate include sodium siliconate, potassium siliconate, lithium siliconate and the like. Among them, sodium methylsiliconate is particularly preferable as the one mass-produced at present and inexpensive. Furthermore when using sodium methyl siliconate is preferably 2 wt% to 30 wt% in CH ₃ SiO _1.5 standards.

When the alkali siliconate is used in combination with sodium silicate, potassium silicate, lithium silicate, etc., when hot work is performed on the vertical wall surface, sagging does not easily occur, and a good and uniform welding glaze layer is formed. It is particularly preferred for such applications. 2% to 30% by weight
When the amount is too small, these effects are small, and when the amount is too large, the cost is increased and the adhesion is unfavorably reduced.

After the application of the alkali siliconate, organic groups such as a methyl group are decomposed and disappear to become SiO ₂ .

In order to apply the glaze of the present invention to the surface of the refractory constituting the inner wall surface of the coke oven, a standard coating method such as application (brush coating, iron coating) or spraying of the composition on a predetermined surface is used. Therefore, for uniform application, it is desirable to provide the composition in the form of an aqueous solution or a slurry close to the aqueous solution. Most of the above-mentioned metal salts and metal compounds are aqueous solutions, and the metal can be easily prepared in a desired composition ratio in the aqueous solution. However, it is also possible to use a slurry in which insoluble or poorly soluble metal salts and metal compounds are dispersed in water. Of course, both water-soluble and water-insoluble precursors can be used in combination.

The concentration of the solid content in terms of metal oxide in the aqueous solution to be applied is usually adjusted to about 5 to about 50% by weight, preferably about 10 to about 40% by weight. When the concentration is about 50% by weight or more, gelation easily occurs due to heat at the time of construction, and clogging of the spray nozzle occurs. On the other hand, when the content is less than about 5% by weight, a large amount of the aqueous solution of the composition is required to form a sufficient film, and the efficiency of construction is reduced. There is no limitation on the thickness of the coating (that is, the glaze layer), but practically it may be about 3 mm or less.

The feature of the glaze of the present invention is that when applied to the inner wall of the furnace, it melts once at the actual furnace temperature of the coke oven (about 1100 ° C) or lower, and then uniformly and densely The coating of the glaze layer is formed, but the melting point of the glaze layer increases with time and does not melt again at the operating temperature of the furnace, so that a firm coating is maintained.

The melting point of the glaze of the present invention needs to be set to not more than the actual furnace temperature and not more than about 900 ° C. in consideration of the peripheral portion of the furnace inner wall refractory. It is also one embodiment of the present invention to appropriately adjust the component ratio of the composition so that the melting point is equal to or lower than the set value. Specifically, in the case of ternary system of _{Li 2 O-Na 2 O-} SiO 2, the phase diagram (e.g., FCKracek, J.Am.Chem.Soc., 61,2871 ( 193
From 9)), determine the weight percentage of each component in an appropriate region having a melting point of 900 ° C. or lower, and adjust the Li ₂ O, Na
_The prescribed amounts of the precursors of ₂ O and SiO ₂ can be mixed to obtain the glaze of the present invention.

In the present invention, the reason why the melting point of the glaze rises after application is considered to be that some of the components in the composition volatilize or diffuse with time. The details of this mechanism do not limit the invention, for example, if Li ₂ O or R ₂ O is SiO ₂
When coexisting with _2, significantly lowering the melting point (if SiO ₂ alone 1728 ° C.). Since these alkali metal oxides have a large diffusion coefficient and a relatively high vapor pressure, they diffuse and volatilize over time after construction, and the composition of the glaze layer approaches the SiO ₂ film.
As a result, the melting point increases. B ₂ O ₃ also has an effect on lowering the melting point and is easy to volatilize, so that it can be used in combination with SiO ₂ like Li ₂ O and R ₂ O.

According to the invention, the composition of the glaze, in terms of oxide as a glaze, Li ₂ O, 0 to about 10 wt%, B ₂ O _3, 0~ about 10 wt%, R ₂
O, from about 10 to 40 wt% and the balance is preferably composed of SiO _2. Li ₂ O, 0.2 to about 10% by weight and / or B ₂ O ₃ ,
It is particularly preferred to contain from 0.5 to about 10% by weight.

Therefore, one preferred glaze composition is R ₂ O, about 1
0 to about 40 wt% and the balance is one that consists of SiO _2.

As a second preferred glaze compositions, Li ₂ O, from about 0.2 to about 10
Wt%, R ₂ O, from about 10 to about 40 wt%, and the balance are those made of SiO _2.

As a third preferred glaze compositions, B ₂ O _3, from about 0.5 to about 10
Wt%, R ₂ O, from about 10 to about 40 wt%, and the balance are those made of SiO _2.

As a fourth preferred glaze compositions, Li ₂ O, from about 0.2 to about 10
Wt%, B ₂ O _3, from about 0.5 to about 10 wt%, R ₂ O, from about 10 to about 40 wt%, and the balance are those made of SiO _2.

If each component is out of the above range in the glaze, it is not preferable because the melting point becomes high or, when further coated, the film formability is poor.

In the prior art, various glazes are known, but because they do not have a composition that takes into account the melting point, the glaze layer melts and flows after construction, exposing refractories, and the glaze layer remains glassy. It becomes like syrup and promotes the adhesion of carbon. Also, the glaze layer may be scraped off by the carbon particles, and satisfactory results have not been obtained.

The present invention also includes an improved glaze characterized by adding a suitable coefficient of thermal expansion regulator to the above glaze.
The temperature inside the coke oven may fluctuate depending on the operation.If the difference in the coefficient of thermal expansion between the refractory and the glaze layer is large, cracks and the like occur in the glaze layer, often deteriorating the carbon adhesion prevention effect of the coating. Occur. Therefore, in order to improve the compatibility between the glaze layer and the refractory, the same or the same type of thermal expansion coefficient as the refractory is preferable as the thermal expansion coefficient adjuster, and particularly preferably, Al ₂ O ₃ , M
One or more selected from the group consisting of gO, CaO, ZrO ₂ and TiO ₂ can be used. The amount used is not more than about 100% by weight of the thermal expansion coefficient adjuster per 100 parts by weight of the glaze. When the thermal expansion coefficient adjusting agent is applied to the glaze, the above range is preferable in order to integrate the glaze layer and form a good coating.

At the time of construction, a glaze composition of the present invention is added with a thermal expansion coefficient adjusting agent (usually a solid powder) to form a slurry, and the composition is applied to the surface of a refractory in the same manner as in the case of the composition.

The thermal expansion coefficient adjusting agent generally has a high melting point, and if the whole is quickly integrated, the composition will have a high melting point, and it will be difficult to form a glaze layer film at a temperature of 900 ° C or less. However, on the other hand, due to the high melting point, the self-diffusion coefficient of the thermal expansion coefficient adjusting agent is small. For this reason, if it is added as a solid powder, portions other than the solid powder are first melted, and a film is formed in a form in which the solid powder itself is wrapped in the glaze layer. Thereafter, the components of the solid powder are diffused with time to form an integrated film as a whole, and a glaze layer having a controlled thermal expansion coefficient can be obtained. When this improved glaze is used, the glaze layer hardly peels off, and the effect of preventing carbon adhesion is further promoted.

In the present invention, the particle size of the constituent particles in the glaze composition is not particularly limited. However, when the particle size is too large, it is difficult to perform the application, and when the particle size is too small, after application, the shrinkage is large and the coating is cracked. Therefore, practically, about 0.5 to about 5
A range of about 0 μm is preferable.

When practicing the present invention, the glaze composition is coated on the inner wall of the coke oven in the manner described above. The work is performed by hot work or heat treatment after low-temperature work. The former is preferable because it can be performed without stopping the operation of the furnace. The coating forms a glaze layer which is dried, melted and sintered by the heat in the furnace during operation. The dense and high-performance glaze layer thus formed has good compatibility with the refractory surface as described above, and keeps preventing carbon deposition without peeling off during furnace operation.
Therefore, a method of applying a glaze to prevent carbon adhesion, a method of forming a glaze layer, and the applied glaze layer itself also constitute a part of the present invention.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in more detail with reference to Examples.
The present invention is not limited by these. In the examples, all “%” represent% by weight.

<Example 1> 3 water glass _{(Na 2 O 8.7%, SiO} 2 27.8%, water 63.5
%) 100 parts by weight, lithium silicate (Li ₂ O 2.2%, SiO ₂ 20
%) And stirred until a completely clear liquid was obtained. This is designated as solution A.

96 parts by weight of lithium hydroxide (LiOH) was added to and dissolved in 959 parts by weight of water. Next, 318 parts by weight of boric acid powder (H ₃ BO ₃ ) was added, and the mixture was stirred to obtain a completely transparent liquid. This is designated as solution B.

Sodium methylsiliconate (Na ₂ O 10.7%, CH ₃
SiO _1.5 20%: 17.9% as SiO ₂ )
2.5 parts by weight were added and the mixture was stirred until a transparent liquid was obtained. This is C
Liquid.

30 parts by weight of the liquid C was added to 100 parts by weight of the liquid A and stirred until a transparent liquid was obtained. This is designated as solution D.

In addition, at the time of these preparations, 70-80 ℃ to speed up
The result did not change even when heating was performed.

The resulting glaze composition Na ₂ O 21.7% as glaze when it becomes an _{oxide, Li 2 O 2.2%, B} 2 O 3 1.1%, SiO 2
75.0%. A commercially available castable brick containing 36% of SiO _{2 and} 54% of Al ₂ O ₃ was cut into 100 × 100 × 40 mm to prepare a test refractory piece.

The test piece was heated in a furnace at 900 ° C. After confirming that the temperature of the brick had risen to 900 ° C., the brick was taken out and, at the same time, the liquid D was sprayed on the brick surface with a spray gun.
Initially, the brick foamed, but after about one minute, it melted and a uniform, strong glass coating was formed. 900 ℃ again
And kept for 2 hours.

A slurry composed of 5 parts of coal powder and 3 parts of coal tar was applied to the brick on which the glaze layer film was formed in this manner, and heated and maintained at 800 ° C. for 3 hours in an inert atmosphere (eg, under nitrogen). After cooling, the adhesion carbon was easily peeled off using an adhesive tape, and the carbon was easily peeled off.

On the other hand, the sample not coated with the glaze composition of the present invention is:
Carbon firmly adhered to the brick surface and could not be completely removed even by applying mechanical force.

<Example 2> No. 3 water glass (Na ₂ O 9.6%, SiO ₂ 27.8%, water 62.6
%) 100%, lithium silicate (Li ₂ O 2.2%, SiO ₂ 20%, water
(77.8%) 4.4 parts by weight were mixed and stirred until a completely transparent liquid was obtained, which was used as Liquid A.

To 100 parts by weight of liquid A, 10.1 parts by weight of water was added, then 2.7 parts by weight of liquid B having the same composition as in Example 1 was added, and finally, sodium methylsiliconate (10.7% of Na ₂ O, CH ₃ SiO _1.5 20.
(0%: 17.9% as SiO ₂ ) was added and stirred until a transparent liquid was obtained. This is designated as solution D.

When the obtained glaze composition became an oxide, the glaze composition was Na ₂ O 25.8%, Li ₂ O 0.4%, B ₂ O ₃ 1.0%, SiO ₂
72.8%.

The composition before the methyl group of sodium methylsiliconate disappeared was SiO ₂ 67.8%, Li ₂ O 0.4%, Na ₂ O
25.6%, B ₂ O ₃ 1.0%, and CH ₃ SiO _1.5 5.2%.

 A test refractory piece similar to that in Example 1 was prepared.

The test piece was placed in a furnace at 900 ° C. and heated. After confirming that the temperature of the brick had risen to 900 ° C., the brick was taken out and, at the same time, the liquid D was sprayed on the brick surface with a spray gun.
Initially, the brick foamed, but after about one minute, it melted and a uniform and strong glass film was formed.

Incidentally, the amount of the above sodium methylsiliconate is 1 /
Except that the composition was changed to 5, a composition having substantially the same composition was used as an E liquid.

The obtained E liquid is used as a glaze composition when it becomes an oxide.
_{Na 2 O 25.0%, Li 2} O 0.5%, B 2 O 3 1.1%, was SiO ₂ 73.5%.

The composition before the methyl group of sodium methylsiliconate disappeared was SiO ₂ 72.4%, Li ₂ O 0.5%, Na ₂ O
24.9%, B ₂ O ₃ 1.3%, and CH ₃ SiO _1.5 1.1%.

This was tested in the same manner as in Example 1, and as a result,
A uniform and strong glass film was formed, but when applied to the vertical surface of the brick, considerable sagging occurred.

<Examples 3 to 6> A glaze composition was prepared in the same manner as in Example 1 so that the composition of the glaze was as shown in Table 1, and the obtained glaze layer was subjected to film formation and peeling of adhered carbon. An evaluation was performed. Table 1 shows the compositions and evaluation results.

<Example 7> 100 parts by weight of the D solution of the glaze composition of Example 1 and 20 parts by weight of alumina powder having an average particle size of 5 µm were mixed to form a slurry to obtain an improved glaze composition. .

This slurry was sprayed on bricks in the same manner as in Example 1. The formed film was not transparent, but the surface was glossy and glassy.

<Comparative Examples 1 and 2> A composition was prepared in the same manner as in Example 1 so that the composition of the glaze was as shown in Table 1, and the obtained glaze layer was evaluated. Table 1 shows the compositions and evaluation results.

Melting point was estimated by visual observation to determine whether the glaze melted and formed a glaze layer when heat-treated at 600 ° C, 700 ° C, 800 ° C, 900 ° C, and 1000 ° C.

From the test results in Table 1, it was clarified that the glaze of the example was excellent in film formation and also had a remarkable carbon adhesion preventing effect, but the glaze of the comparative example was inferior in both.

<High Temperature Retention Test> The brick covered with the glaze layer obtained in Example 1 was held at a temperature of 900 ° C. for about 5 hours, and the components in the glaze layer coating of the baked brick were analyzed to find that SiO ₂ / Na ₂ O mol The ratio was 3.5, and Na ₂ O tended to decrease compared to the initial 3.0.

When the temperature is further maintained at 1100 ° C. for 1 hour, the molar ratio is 7.5 and Na ₂ O
Remarkably decreased. At this time, B ₂ O ₃ and Li ₂ O were not detected. The melting point of this glaze layer was 1300 ° C or higher, and a remarkable melting point increasing effect was observed from the initial melting point of 800 ° C or lower.

INDUSTRIAL APPLICABILITY By applying the glaze according to the present invention hot on the inner wall surface of the coke oven, a dense and durable glaze layer is formed on the wall surface. As a result, the adhesion of carbon generated by thermal decomposition of tar or the like can be greatly reduced, and even if carbon adheres, it can be easily peeled off, and the life of the coke oven can be extended. Since the glaze according to the present invention can be easily hot-worked, it is performed without hindering the normal operation of a coke oven, is effective in terms of manpower, materials and costs, and the present invention is extremely useful industrially.

Claims (9)

(57) [Claims] As claimed in claim 1] Composition for forming a glaze, on an oxide basis, Li ₂ O is 0 to 10 wt%, B ₂ O ₃ is 0-10 wt%, R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
A glaze for hot application to a coke oven refractory or a glaze for hot application to a coke oven refractory for preventing carbon adhesion, characterized by containing O _{2 and} having a melting point of 900 ° C. or less. 2. The composition for forming the glaze layer is such that Li ₂ O is 0 to 10% by weight, B ₂ O ₃ is 0 to 10% by weight, R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
Hot application to coke oven refractories, characterized by adding 100 parts by weight or less of thermal expansion regulator to 100 parts by weight of glaze containing O ₂ and melting point of glaze is 900 ° C or less Glaze for hot application to coke oven refractories for preventing glaze or carbon adhesion. 3. The method of claim _{2, wherein the} thermal expansion coefficient adjusting agent is Al ₂ O ₃ , MgO, CaO, ZrO ₂
And glaze of claim 2, wherein the chosen from the group consisting of TiO _2. 4. The glaze according to claim 1, comprising 0.2 to 10% by weight of Li ₂ O. 5. The glaze according to claim 1, comprising 0.5 to 10% by weight of B ₂ O ₃ . 6. The compound forming SiO ₂ is sodium silicate,
The glaze according to any one of claims 1 to 5, comprising at least one selected from the group consisting of potassium silicate and lithium silicate and an alkali siliconate. 7. The glaze according to claim 6, wherein the alkali siliconate is sodium methylsiliconate and is 2% to 30% by weight based on CH ₃ SiO _1.5 . 8. The glaze according to claim 1, wherein the refractory of the coke oven is selected from the group consisting of bricks, joints and irregular refractories. 9. The composition for forming a glaze layer is, as oxides, 0 to 10% by weight of Li ₂ O, 0 to 10% by weight of B ₂ O ₃ , and R ₂ O
(R represents Na or K) is 10 to 40% by weight, and the balance is Si
A method for forming a glaze layer, characterized by hot-working a glaze containing O _{2 and} having a melting point of 900 ° C. or less on the inner wall of a coke oven to form a glaze layer by welding.