JPS61134584A - Hot spray repairing method - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

[Detailed Description of the Invention] Industrial Fields of Application The present invention is applicable to blast furnaces, converters, ladles, pig iron mixers, tandesos,
This invention relates to a method for hot spraying repair of the lining of a vacuum degassing furnace or the lining of equipment associated therewith.

Conventional spraying is a repair method in which a spraying material made by adding a binder such as an alkali metal salt to fire-resistant aggregate such as magnesia clinker or dolomite clinker is directly applied to the repair area in a muddy state by adding water. It is sprayed. The conditions required for this method are the adhesion of the spray material and the durability after adhesion.

There are two methods for spraying: a wet method, which uses a spraying material that has been made into mud beforehand, and a dry method, in which water is sometimes added near the tip of the nozzle. The wet method has drawbacks such as the need to adjust the spray to a solid state at the repair site and the tendency to clog the nozzle, so the dry method is actually used more often due to its workability.

Problems to be Solved by the Invention In order not to reduce the operating rate of the furnace to be repaired, so-called hot spraying repair is performed in which the furnace wall surface is not sufficiently cooled. This method has more rebound loss than cold repair and has extremely poor adhesion. In addition, the vapor pressure associated with the rapid evaporation of moisture causes blisters on the surface of the spray material after it has been deposited, resulting in poor durability.

As a countermeasure against this problem, it is known to use a spray material to which a water-insoluble binder such as tar or pitch is added, as shown in, for example, Japanese Patent Application Laid-Open No. 54-125105.

Tar, pitch, and the like have high adhesiveness, so they have a strong adhesion force to the spray material, and they do not cause blisters on the surface of the spray material. However, since tar and pinch soften and melt when heated by the furnace wall, it takes time for them to become sticky, and they hardly stick unless the surface to be repaired is nearly horizontal. In addition, the smoke emitted from tar and pitch is significant, making it difficult to observe the repair status and creating a poor working environment9.As for the spraying method, as mentioned above, the dry method is the mainstream.

This method generates a lot of heat because the powder is in a dry state. Therefore, it is known to add a small amount of water to the spray material in advance and add an aqueous solution of water glass near the tip of the nozzle. In this way, since the spray material contains water, it is possible to prevent bleeds even in a dry method.

However, adding a binder occasionally during spraying is very troublesome as it requires controlling the amount of binder added and replenishing the binder. Furthermore, since the binder is not mixed sufficiently, the adhesion of the sprayed material and the durability after adhesion are reduced.

Means for Solving the Problems The present inventor has repeatedly investigated hot spraying using a dry method in order to solve the above-mentioned conventional drawbacks in repair. As a result, by adding a small amount of alcoflu to the spray material and mixing it in advance, the spray material has excellent adhesion and durability after adhesion, and it also solves the issue of eruption without reducing workability. The spraying material, which is mainly made of mollusc salts, is heated to a boiling point of 15 in advance.
Hot spraying is a repair method characterized by adding and mixing 0.1 to 3 wt% of the above alcohols and then spraying using a dry method.
1 The alcohol used here may be either monohydric or polyhydric alcohol as long as it has a boiling point of 150r or higher.

If the boiling point is less than 150r, there is no effect of preventing blistering of the sprayed layer, which is one of the effects of the present invention.

The upper limit of the boiling point is not particularly limited, but considering the nature of the alcohol, the upper limit is about 300"C. Specific examples are furfuryl alcohol for monohydric, ethylene glycol, glycerin, diethylene glycol for polyhydric. , triethylene glycol, propylene glycol, polyethylene glycol, tetraethylene glycol, dipropylene glycol, hexylene glycol, diglycerin, etc.Of course, two or more of these may be combined.The amount added is based on the total amount of the spray material. Q, l against Europe
If it is less than wt%, the addition has no effect. If it exceeds 8 wt%, the wetness level of the spray material becomes high and nozzle clogging occurs.The content is preferably 0.3 to 5 wt%.

The refractory aggregate, binder, and other additives that compose the spray material may be the same as conventional ones. Specific examples of fire-resistant aggregates include magnesia clinker and dolomite clinker 1.
The clinker is one or more selected from lime clinker, maguro clinker, spinel clinker-1 limestone, chromite, zircon sand, bauxite, clay shale, waxite, chamotte, and brick waste. The particle size is the maximum particle size, for example 3
The temperature should be below snow, and adjustments should be made as appropriate to obtain dense packing within this range.

In addition, magnesia clinker, dolomite clinker,
CaO-containing refractory aggregates such as magdro clinker and lime clinker undergo structural deterioration due to hydration reactions. The addition of alcohol coats the surface of the refractory aggregate and prevents it from coming into contact with water vapor in the air, which can cause hydration. Therefore, according to the present invention, even when using CaO-containing refractory aggregate, the spray material has good shelf life.

The binder is alkali metal, alkaline earth metal phosphate,
One or more selected from alkali metal salts such as silicates, borates, and aluminum phosphates are used. Specific examples include sodium tripolyphosphate, sodium hexametaphosphate,
Alkali metal phosphates such as acidic sodium hexametaphosphate, sodium pyrophosphate, acidic sodium pyrophosphate, monobasic sodium phosphate, monobasic potassium phosphate, alkaline earth metals such as monobasic calcium phosphate, monobasic magnesium phosphate, etc. These include phosphates, borates such as sodium borate, silicates such as sodium metasilicate, primary to tetrahydrous sodium silicate, lithium silicate, and primary aluminum phosphate. The proportion to the refractory aggregate is usually 1 to IQ wt%, preferably 2 to (3 wt%).

In addition to the above, a coagulant for a binder, a plasticizer, short fibers, metal powder, etc. may be added to the spray material as necessary. Examples of the flocculant of the binder include slaked lime, magnesium oxide, ammonium silicate, aluminum chloride, calcium chloride, calcium sulfate, magnesium sulfate, and calcium phosphate in a proportion of 6 wt% or less.

Examples of the plasticizer include bentonite, clay, dextrin, CMC, and silica flour. The preferred proportion to the refractory aggregate is 8 wt% or less.

The short fibers are ceramic fibers and/or organic fibers. Examples of the ceramic fiber include asbestos, aluminosilicate am, siliceous fiber, alumina fiber, zirconia fiber, slag wool, potassium titanate fiber, and the like.

Examples of organic fibers that can be used include synthetic fibers such as vinylon fibers, polyester fibers, and polyester fibers, as well as pulp fibers, cotton fibers, regenerated fibers, cotton wool, and wool. Although the length depends on the fiber diameter, it is preferably 1 to 201 DI. Also, for example, for refractory aggregates. The preferred proportion to the refractory aggregate is 6 wt% or less.

The present invention first involves applying alkaline to a spray material made of the following compounds.
- Add the ingredients and mix. For repairs, the spraying material thus obtained is sprayed using the conventional dry method.

That is, water is added to the spray material near the tip of the nozzle, and the spray material is sprayed onto the surface to be repaired in a muddy state.

Note that a conventional dry spray gun can be used in the method of the present invention.

By adding alcohol to the spray material in advance, the surface of the fire-resistant aggregate is coated with the alcohol, increasing the wettability of the spray material. For this reason, the spray material mixes quickly with the water added within the nozzle and has a uniformity of 150 to 800'c. According to the present invention, flowering of the sprayed layer can be prevented. This is presumed to be because the addition of alcohols with a high boiling point increases the boiling point of water, which reduces the rate of evaporation of water from the sprayed layer, thereby relieving the rapid evaporation of water.

Alcohols have high wettability for fire-resistant aggregates,
Furthermore, since the surface tension is low, even if added in small quantities, it is widely distributed in the spray material.

Effects According to the present invention, the adhesion of the sprayed material is improved, and there is very little rebound even during hot repairs. Therefore, there is an effect of reducing the amount of sprayed material in the furnace and shortening the repair time.

Flowers caused by evaporation of water in the sprayed layer can be prevented.

When flowers occur as in the conventional method, the structure of the sprayed layer becomes brittle, resulting in poor corrosion resistance against molten metal and molten slag, and may peel off from the voids formed by the flowers. On the other hand, according to the examples of the present invention, even if the surface to be repaired is at a high temperature of 1000°C, no flowers are observed, and the same effect can be obtained by adding a tightening agent to the sprayed layer. Since alcohol easily wets the refractory aggregate and has a low surface tension, even a small amount of alcohol has a large effect in preventing rash. Moreover, unlike water, alcohol does not have the effect of hardening the alkali metal salt as a binder, so even if it is added in advance, there is no risk that the spray material will harden before being sprayed.

As described above, according to the present invention, a hot spraying repair method that is excellent in both repair efficiency and work environment can be obtained.

EXAMPLES Examples of the present invention will be shown below, but the present invention is not limited thereto.

(Example) A spraying material to which an alcohol having a boiling point of 150'c- or higher was added and mixed in advance was sprayed by a dry method.

(Comparative Example 1) Spraying was performed using a conventional dry method without adding alcohol.

(Comparative example 2) A spray material containing pitch particles was sprayed using a dry method.

(Comparative Example 3) A spraying material to which 2 wt % of water was added and mixed in advance was sprayed by a dry method. The binder was added from the nozzle tip as a 19 wt % water glass solution.

(Comparative Example 4) Methyl alcohol with a boiling point of 150% or less (boiling point 65%
(Test Method) Both the Example and Comparative Example were tested under the same conditions.The target object was vertically stacked magnesia with a surface temperature of 1000℃. It was a brick wall. During spraying, the amount of water added to the spray material near the nozzle tip is 16 to 18 wt%.

Landing rate: Calculated from rebound loss.

Occurrence of flare: The cross section of the sprayed layer was observed.

Occurrence of blister: The conditions during spraying were observed. *The pitch grains used in Comparative Example 2 were granulated by the dropping method from heated and melted pitch.

As is clear from the test results in the table, the examples of the present invention:
Good results were shown in terms of adhesion rate, occurrence of flare, and occurrence of rash. Comparative Example 2, in which pitch particles were added to the spray material, was not shown in the test results in the table, but smoke generation from the pinch particles was significant. In Comparative Example 3, since the binder was added near the tip of the nozzle, the spraying process was complicated. Comparative example 4 is
Due to the low boiling point of alcohol, it was not possible to prevent flare in the sprayed layer. Also, although not shown in the table, Example ■
When 20 wt% of ethylene glycol was added to the spray material, which is outside the scope of the present invention, nozzle clogging occurred.
It was not possible to spray using the dry method.

Patent applicant: Harima Refractory Brick Co., Ltd. Procedural amendment (method) ■, Indication of the case: 1982 Patent Application No. 254707 2, Name of the invention: Hot spraying is a repair method 3, Person making the amendment: Relationship with the case: Patent application Person 4. Date of amendment order (shipment date) March 26, 1985 5. Full text of specification subject to amendment - 46゛

Claims (1)

[Claims] A fire-resistant aggregate and a spraying material mainly containing an alkali metal salt as a binder are pre-coated with 0.0% alcohol having a boiling point of 150°C or higher.
A hot spraying repair method characterized by adding and mixing 1 to 8 wt% and then spraying by a dry method.