JPH0648138B2 - Spray repair method - Google Patents

Description

TECHNICAL FIELD The present invention relates to a blast furnace, a converter, a ladle, a hot metal wheel, a tundish,
The present invention relates to a method of spraying and repairing an inner lining of a vacuum degassing furnace or the like, or an inner lining of equipment accompanying it.

Conventional technology The spray repair method is, for example, spraying a spray material made by adding a binder such as an alkali metal salt to a refractory aggregate such as magnesia clinker or dolomite clinker in a sludge state by adding water. It is a thing. The conditions required for this method are the adhesion of the spray material and the durability after adhesion.

Further, the spraying method includes a wet method using a spraying material that has been preliminarily sludged, and a dry method in which water is added near the nozzle tip during spraying. The wet method has drawbacks such as that the spray material must be adjusted to a sludge state at the repair site and that nozzle clogging is likely to occur, and in practice, the dry method is often used from the viewpoint of workability.

Problems to be Solved by the Invention There is so-called hot spray repair in which repair is performed while the furnace wall surface is not sufficiently cooled in order not to reduce the operating rate of the furnace to be repaired. Compared with cold repair, this method has more rebound loss and extremely poor adhesion. Further, the vapor pressure caused by the rapid evaporation of water causes blistering on the surface of the sprayed material after adhesion, resulting in poor durability.

As a countermeasure against this, it is known to use a spray material to which a water-insoluble binder such as tar or pitch is added, as seen in, for example, JP-A-54-125105. tar,
Since the pitch and the like have high adhesiveness, the adhesive force of the sprayed material is large, and moreover, the surface of the sprayed material does not have blisters.
However, since tar and pitch are softened and melted by being heated by the wall surface of the furnace, it takes time until tackiness occurs, and almost no adhesion occurs unless the surface to be repaired is near horizontal.
Further, it is difficult to observe the repair status because the smoke from tar and pitch is remarkable, and the working environment is bad.

As the spraying method, the dry method is mainly used as described above.
This method is very dusty because it handles dry powder. Therefore, it is known that a small amount of water is previously added to the spray material, and an aqueous solution of water glass is added near the tip of the nozzle. In this case, since the spray material contains water, dust can be prevented even by the dry method. However, it is very troublesome to add the binder at the time of spraying because it is necessary to control the addition amount of the binder and replenish the binder. Moreover, since the mixing of the binder is insufficient, the adhesion of the spray material, the durability after adhesion, and the like decrease.

Means for Solving the Problems The inventor of the present invention has made repeated studies in order to solve the above-mentioned conventional defects in the spray repair by the dry method. As a result, if a small amount of alcohol is added to the spray material beforehand and mixed, the spray material will have excellent adhesiveness and durability after adhesion,
Moreover, they have found that the problem of dust generation can be solved without lowering workability, and have completed the present invention. That is, the present invention provides a spray material containing a refractory aggregate, one or more selected from alkali metal or alkaline earth metal phosphates, silicates, borates and aluminum phosphates,
This is a spray repair method characterized in that 0.1 to 8 wt% of alcohols having a boiling point of 150 ° C. or higher is added and mixed, and then sprayed by a dry method.

The alcohols used here may be monohydric or polyhydric alcohols as long as the boiling point is 150 ° C. or higher. Boiling point is
If the temperature is lower than 150 ° C, there is no effect of preventing blistering of the spray layer, which is one of the effects of the present invention. The upper limit of the boiling point is not particularly limited, but due to the nature of alcohols, the upper limit is
It is about 300 ℃. Specific examples thereof include furfuryl alcohol for monohydric, ethylene glycol, glycerin, diethylene glycol, triethylene glycol for polyhydric,
Propylene glycol, polyethylene glycol, tetraethylene glycol, dipropylene glycol, hexylene glycol, diglycerin and the like. Of course, two or more of these may be combined. If the added amount is less than 0.1 wt% with respect to the total amount of the sprayed material, the effect due to the addition is not obtained. If it exceeds 8 wt%, the degree of wetting of the spraying material becomes high and nozzle clogging is likely to occur, making spraying by the dry method difficult. Most preferably, it is 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 the refractory aggregate include magnesia clinker, dolomite clinker,
It is one or more selected from lime clinker, magcro clinker, spinel clinker, limestone, chrome ore, zircon sand, bauxite, shale shale, wax, chamotte, brick scraps and the like. The maximum particle size is, for example, 3
mm or less, and adjust appropriately so that close packing can be obtained within this range.

In addition, magnesia clinker, dolomite clinker,
CaO-containing refractory aggregates such as magdro clinker and lime clinker cause tissue deterioration due to hydration. Addition of alcohols covers the surface of the refractory aggregates, eliminating contact with water vapor in the air, which causes hydration. Therefore,
According to the present invention, even if the CaO-containing refractory aggregate is used, the storability of the spray material is good.

As the binder, at least one selected from alkali metal or alkaline earth metal phosphates, silicates, borates, and aluminum phosphates is used. Specific examples thereof include sodium tripolyphosphate, sodium hexametaphosphate, acidic sodium hexametaphosphate, sodium pyrophosphate, acidic sodium pyrophosphate, first sodium phosphate, alkali metal phosphates such as first potassium phosphate, first calcium phosphate, Alkaline earth metal phosphates such as primary magnesium phosphate, alkali metal borates such as sodium borate, sodium metasilicate, first to fourth sodium silicates, and alkali metal silicates such as lithium silicate. . The ratio to the refractory aggregate is usually 1 to 10% by weight, preferably 2 to 6% by weight.

In addition to the above, a flocculant of a binder, a plasticizer, a short fiber, a metal powder and the like may be added to the spray material, if necessary. Examples of the coagulant of the binder include slaked lime, magnesium oxide, ammonium silicofluoride, aluminum chloride, calcium chloride, calcium sulfate, magnesium sulfate, dicalcium silicate, chrome slag, magneslag, and monoaluminum phosphate. The preferable ratio to the refractory aggregate is 6 wt% or less.

Examples of the plasticizer include bentonite, clay, dextrin, CMC, silica flour and the like. The preferable ratio 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 fiber, siliceous fiber, alumina fiber, zirconia fiber, slag wool, potassium titanate fiber, and the like. As the organic fibers, for example, synthetic fibers such as vinylon fibers, polyester fibers, and polyester fibers, as well as pulp fibers, cotton fibers, recycled fibers, denier cotton, and wool can be used. The length depends on the diameter of the fiber, but is preferably 1 to 20 mm. Further, the preferable ratio to the refractory aggregate is 3 wt% or less.

The metal powder is, for example, Al, Si, Mg, Fe, Ti, Cr, or an alloy thereof such as Al-Mg, Fe-Si. The preferable ratio to the refractory aggregate is 6 wt% or less.

In the present invention, first, alcohols are added to and mixed with a spray material composed of the above-mentioned compound. At the time of repair, the spray material thus obtained is sprayed by the conventional dry method. That is, water is added to the spray material near the nozzle tip, and the spray material is sprayed on the surface to be repaired in a sludge state.

The method of the present invention can use a conventional dry spray gun.

Action By adding alcohol to the spray material in advance, the surface of the refractory aggregate is covered with alcohol, and the wettability of the spray material is increased. For this reason, the spray material is quickly and uniformly mixed with the water added in the nozzle, and the adhesiveness is improved.

The boiling point of alcohols is 100 ℃ or higher, the main one is 150-300
℃. According to the present invention, blistering of the spray layer can be prevented. It is presumed that this is because the boiling point of water is increased by the addition of alcohols having a high boiling point, the evaporation rate of water from the spray layer is reduced, and rapid evaporation of water is mitigated.

Alcohols have high wettability to refractory aggregates,
Also, since the surface tension is small, even a small amount of addition will spread widely in the spray material.

Effect According to the present invention, the adhesion of the sprayed material is improved, and rebound is extremely small even during hot repair. Therefore, there is an effect that the amount of sprayed material used is reduced and the repair time is shortened.

It is possible to prevent swelling due to evaporation of water in the spray layer. When blister occurs like the conventional method, the structure of the spray layer weakens,
It is inferior in corrosion resistance to molten metal and molten slag, and may be peeled from voids formed by blisters. On the other hand, according to the embodiment of the present invention, the surface to be repaired is 1000
Almost no blistering was observed even at a high temperature of ℃, and the service life of the spray layer was more than double that of the conventional method.

Addition of alcohols prevents dusting during spraying, which is preferable from the working environment. The same effect can be obtained by adding water in advance, but alcohols are easy to wet the refractory aggregate and have a small surface tension, so even if added in a small amount, they are effective in preventing dust emission. Is big. Moreover, since alcohols do not act to harden the binder like water, even if added in advance, there is no risk that the spray material will harden before spraying.

As described above, according to the present invention, a spray repair method having excellent repair efficiency and working environment can be obtained.

Examples Hereinafter, examples of the present invention will be shown, but the present invention is not limited thereto.

(Example) A spray material prepared by previously adding and mixing alcohols having a boiling point of 150 ° C or higher was sprayed by a dry method.

Comparative Example 1 Spraying was performed by a conventional dry method without adding alcohols.

(Comparative Example 2) A spray material containing pitch grains was sprayed by a dry method.

(Comparative Example 3) A spraying material containing 2% by weight of preliminarily added water and mixed was sprayed by a dry method. The binder was added from the nozzle tip as a 10 wt% solution of water glass.

(Comparative Example 4) A spray material prepared by previously adding and mixing methyl alcohol having a boiling point of 150 ° C or lower (boiling point 65 ° C) was sprayed by a dry method.

(Test Method) The test was carried out under the same conditions in both Examples and Comparative Examples. The spraying target was a vertically stacked magnesia brick wall with a surface temperature of 1000 ° C. During spraying, the amount of water added to the spraying material near the tip of the nozzle is 16-18 wt%.

Adhesion rate; Calculated from bounce loss.

Occurrence of blisters: A cross section of the spray layer was observed.

Occurrence of dust; observed the situation during spraying * The pitch particles used in Comparative Example 2 are obtained by heating and melting the pitch particles and granulating them by the dropping method.

As is clear from the test results in the table, the examples of the present invention,
The adhesion rate, generation of blisters, and generation of dust show good results. Comparative example 2 in which pitch particles are added to the spray material
Although not shown in the test results in the table, smoke is significantly emitted from the pitch grains. In Comparative Example 3, the spraying work was complicated because the binder was added near the tip of the nozzle. Comparative Example 4
Could not prevent blistering of the spray layer due to the low boiling point of alcohols. Although not shown in the table, when ethylene glycol was added to the spray material of Example 1 in an amount outside the range of the present invention of 20 wt%, nozzle clogging occurred and spraying could not be performed by the dry method.

Claims (1)

[Claims] 1. A spray material containing a refractory aggregate and one or more selected from alkali metal or alkaline earth metal phosphates, silicates, borates and aluminum phosphates as a binder. A spray repair method characterized in that 0.1 to 8 wt% of an alcohol having a boiling point of 150 ° C. or higher is added in advance and mixed, and then sprayed by a dry method.