JP2003073174A - Monolithic refractory for wet gunning and wet gunning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To solve the problem of flaking damage of a wet spraying monolithic refractory without impairing sticking performance and corrosion resistance. SOLUTION: The monolithic refractory is that the previously kneaded monolithic refractory is gunned with a high-speed setting added just before gunning, wherein 100 mass% refractory aggregate of monolithic refractory for wet gunning, is added with 0.01-3 mass% calcium lactate and a dispersion agent, and the monolithic refractory is used in a method for wet gunning.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory for wet spraying used for lining of a molten metal container, a molten metal transfer device, a molten metal processing device, a high temperature furnace, etc. The wet spraying method.

[0002]

2. Description of the Related Art As a method for spraying irregularly shaped refractories,
A wet spraying construction method has been proposed in which a quick-setting agent is added and sprayed immediately before spraying on an amorphous refractory that has been kneaded in advance. Compared to the dry spraying construction method in which construction water is added in the nozzle, it has better adhesion and less dust.

Alumina cement is used as a binder for the amorphous refractory used in the wet spraying method (Example of JP-A-2000-233976). Also, the use of aluminum lactate has been proposed (Japanese Patent Laid-Open No. 10-194853).

Alumina cement or aluminum lactate reacts with the quick-setting agent, and is effective in improving the adhesiveness and developing the strength of the construction body. Amorphous refractory with addition of alumina cement will cure if not used immediately after kneading,
The amorphous refractory to which aluminum lactate is added does not cure even after kneading unless a quick-setting agent is added at the time of spraying, so that the material can be easily handled.

[0005]

However, any of the conventional amorphous refractories for wet spraying (hereinafter, simply referred to as irregular refractory) has a problem of peeling damage. Irregular shaped refractories in spraying work exert their effect by being attached and retained on the wall surface, so no matter how excellent the corrosion resistance is, if they are peeled off, they will reach the end of their life immediately. Thus, peeling damage is fatal.

An object of the present invention is to improve the problem of peeling damage in an amorphous refractory for wet spraying without impairing the effects of adhesion and corrosion resistance.

[0007]

DISCLOSURE OF THE INVENTION The present invention is an amorphous refractory in which an amorphous refractory that has been kneaded in advance is sprayed by adding a quick-setting agent immediately before spraying, and the refractory aggregate is made to have a mass of 100% by mass. On the other hand, it is an amorphous refractory for wet spraying, which comprises 0.01 to 3% by mass of calcium lactate and a dispersant. Moreover, it is a wet spraying construction method using the same.

The amorphous refractory material of the present invention can greatly improve the problem of peeling damage. Moreover, it also exhibits excellent effects on adhesion and corrosion resistance. The reason why these effects are obtained is presumed to be as follows.

The main material of the refractory aggregate of the amorphous refractory is generally alumina, magnesia, silica or the like. After the construction of the alumina cement-added product, the Ca component contained in the alumina cement reacts with the refractory aggregate component in the heat while Al ₂
O ₃ -SiO ₂ -CaO-based or MgO-SiO ₂ -
A low melting point substance such as CaO is generated, and the structure of the construction body shrinks. The wall surface of the container or the device to be sprayed repeatedly expands and contracts due to the temperature change accompanying the operation of the container or the device, but the contraction occurs because the construction body tissue after contraction cannot follow the expansion of the wall surface, This causes peeling damage.

On the other hand, the aluminum lactate-added product produces less low-melting point substances, unlike the alumina-cement-added product. However, since the generation of the low melting point substance is small, the stress generated by the thermal expansion of the construction body cannot be absorbed and relaxed, the internal stress of the construction body becomes high, and crevices are generated, which causes peeling damage.

In order to control the production amount of the low melting point substance, addition of Ca components such as lime and slaked lime can be considered.
However, when the Ca component is added, the amorphous refractory material begins to harden immediately after kneading and is not easy to handle during construction. Further, since the curing is fast, the distribution in the transfer passage of the construction device is not smooth, and the workability is deteriorated by intermittent discharge, blockage of the transfer passage, and the like.

In contrast, the amorphous refractory material of the present invention contains calcium lactate. Since calcium lactate contains CaO component, the construction body tissue produces CaO-based low melt,
Since the amount of CaO-based low-melting material generated is smaller than that of the alumina cement-added product, the contraction of the construction body is small and peeling damage is hardly seen.

Further, calcium lactate appropriately forms a CaO-based low-melting material, and appropriately absorbs and relaxes the thermal expansion stress of the construction body. Therefore, there is no peeling damage caused by the internal stress of the construction body seen in the aluminum lactate-added product.

In the alumina cement added product, the quick-setting agent reacts with the Ca component in the alumina cement to exhibit adhesiveness. Further, the aluminum lactate-added product exhibits adhesiveness by reacting with the quick-setting agent and the lactic acid component in aluminum lactate. On the other hand, calcium lactate has both Ca and lactic acid components of both alumina cement and calcium lactate, so it has a high reactivity with quick-setting agents, and is better than conventional products with alumina cement and aluminum lactate. It is even more excellent in adhesion.

It is known to use alkali aluminate, alkali silicate, calcium aluminate, calcium oxide or the like as a quick-setting agent added to an irregular shaped refractory immediately before spraying. In the present invention, when alkali silicate among them is used,
The lactic acid component contained in calcium lactate undergoes gelation reaction with the silicic acid component of alkali silicate, further improving the adhesiveness. Further, the Ca component contained in calcium lactate reacts with the alkali component of the alkali silicate, and the hardening speed of the construction body is further increased. Thereby, the curing time of the construction body can be shortened and the operation rate of the construction target equipment can be improved.

Since the aluminum lactate-added product does not contain a Ca component in aluminum lactate, even if an alkali silicate is used as a quick-setting agent, the above-mentioned remarkable effect in the curing rate cannot be obtained.

The adherability of the alumina cement-added product is improved in proportion to the increase in the amount of alumina cement. However, the effect is not as remarkable as the aluminum lactate-added product of the present invention. In order to raise the adhesion to the level of the calcium lactate-added product of the present invention, a considerable amount of alumina cement must be added. A material to which a large amount of alumina cement is added has a significantly reduced corrosion resistance and is not practical.

When the amorphous refractory material is heated and dried after construction, if it is rapidly heated to shorten the drying time, blistering or explosion of the construction body due to water vapor pressure occurs. Therefore, it is known to add organic short fibers to solve this problem. The organic short fibers form an escape path for water vapor by being contained in the construction body and prevent blistering or explosion of the construction body. However, the amorphous refractory to which organic short fibers are added has a high viscosity after kneading, which causes a decrease in the fluidity of the amorphous refractory.Therefore, when spraying using a nozzle, the flow in the pressure feed pipe is reduced. Is not smooth, and the workability is inferior accordingly. For example, in the alumina cement-added product, the amount of the organic short fibers added is limited to 0.3% by mass when applied to the refractory aggregate in order to ensure workability.

On the other hand, the amorphous refractory of the present invention using calcium lactate is necessary for the construction even if the amount of the organic short fibers added exceeds 0.3% by mass, for example, by external coating on the refractory aggregate. Has sufficient liquidity. As a result, it becomes possible to increase the addition of the organic short fibers, and the drying effect of the organic short fibers is improved.

[0020]

BEST MODE FOR CARRYING OUT THE INVENTION The calcium lactate used in the present invention is a compound of lactic acid and calcium, and its typical chemical formula is C ₆ H ₁₀ O ₆ Ca.0-5H ₂ O. A common application is food additives such as calcium agents for nutritional enhancement. The production method is obtained, for example, by purifying crude calcium lactate obtained by adding calcium carbonate as a neutralizing agent during lactic acid fermentation. It can also be obtained by evaporating a solution obtained by neutralizing dilute lactic acid with calcium carbonate.

In the amorphous refractory material of the present invention, if the addition ratio of calcium lactate is less than 0.01% by mass with respect to 100% by mass of the refractory aggregate, the effects of the present invention such as peeling damage prevention and adhesion are obtained. Absent. If it exceeds 3% by mass, the amount of Ca in the amorphous refractory material increases, resulting in sintering shrinkage and deterioration in corrosion resistance. A more appropriate range is 0.1 to 2% by mass.

The type of refractory aggregate is not particularly limited, and examples thereof include alumina, bauxite, shale shale,
Mullite, silica, chamotte, andalusite, pyrophyllite, silicon carbide, fused silica, magnesia, magnesia-
Calcia, Al ₂ O ₃ -MgO spinel, chrome ore,
It is one or more selected from sillimanite and the like. These are used as the main aggregate.

If necessary, one or more refractory aggregates selected from volatile silica, calcined alumina, zirconia, graphite, clay, light burned magnesia, pitch, carbon black and the like are further combined. In particular, volatile silica and calcined alumina are ultrafine powders, and are effective for imparting fluidity during construction and densifying the construction body.

The particle size of the refractory aggregate is not different from the conventional one, and it is appropriately adjusted to coarse particles, medium particles, and fine particles in consideration of the fluidity and filling property of the amorphous refractory material.

The dispersant is also called a deflocculating agent, and has the effect of reducing the amount of water added during construction by imparting fluidity during the construction of an amorphous refractory. The preferable addition amount is 0.01 to 1 with respect to 100% by mass of the refractory aggregate as in the conventional material.
It is% by mass.

Specific examples of the dispersant are not particularly limited, and include, for example, sodium tripolyphosphate, sodium hexametaphosphate, sodium polyacrylate, sodium polyacrylate, polycarboxylic acid, sodium ligninsulfonate, and polyether dispersion. It is one or more selected from agents and the like.

The organic short fibers have the effect of improving the drying property. Specific examples thereof are one or more selected from vinylon, PVA, rayon, polyester, nylon, polypropylene, polyethylene and the like. The size is, for example, 1 to 4 denier and the length is 1 to 10 mm. Refractory aggregate 1
When it exceeds 2% by mass with respect to 00% by mass, both workability and corrosion resistance decrease. More preferable amount of addition is refractory aggregate 1
It is 0.05-1 mass% with respect to 00 mass%.

In addition to the above, ceramic short fibers, metal short fibers, metal powder, thickeners, lightweight materials, coarse particles, hardening accelerators, hardening retarders, which are known as additives for amorphous refractories, Other binders and the like may be combined.

The metal powder also serves as a sintering agent. Further, when a carbonaceous raw material is used for the refractory aggregate, it has an effect as an antioxidant. Specific examples are aluminum, silicon, ferrosilicon, aluminum alloys, silicon alloys and the like. The amount added is 5% with respect to 100% by mass of refractory aggregate.
It is not more than mass%, more preferably 0.1 to 3 mass%.

Further, these metal powders may be added to the irregular-shaped refractory material immediately before spraying by mixing in a quick-setting agent described later.

Examples of the thickener include bentonite and C
MC and the like. The ratio of addition is 100 refractory aggregates.
5 mass% or less is preferable with respect to mass%.

The amorphous refractory having the above composition is
Water or other kneading liquid is added and kneaded in advance at the time of construction. As other kneading liquids, alcohol, liquid resin and the like can be considered, but it is preferable to use water from the viewpoint of economy and environment.

The addition amount of the kneading liquid is not particularly different from the conventional one,
It is, for example, 3 to 20 when applied to the entire amorphous refractory composition.
Mass%

The quick-setting agent added to the amorphous refractory immediately before spraying has the effect of imparting adhesiveness. The amount of the quick-setting agent added to the irregular-shaped refractory (excluding the kneading liquid) is
0.1 to 3 mass% based on the solid content is preferable. 0.1 mass%
If the amount is less than the range, the adhesion is insufficient, and if it exceeds 3% by mass, the corrosion resistance tends to be poor.

The quick-setting agent is also called an aggregating agent or a curing accelerator. Specific examples include hydroxides such as calcium hydroxide, sodium hydroxide and potassium hydroxide, alkali aluminates such as sodium aluminate, potassium aluminate and calcium aluminate, silicic acid such as sodium silicate, potassium silicate and lithium silicate. Inorganic acid salts such as alkali, phosphoric acid, phosphate, nitric acid, nitrate, hydrochloric acid, chloride and the like. Moreover, you may combine with a cationic or anionic flocculant as needed. These quick-setting agents can be used in the form of solutions, suspensions or powders.

In the present invention, of these, the use of alkali silicate is particularly preferable in terms of adhesion and curing characteristics. The alkali silicate may be in the form of powder or an aqueous solution, but an aqueous solution that is easily dispersed uniformly in an amorphous refractory is preferable. Taking sodium silicate as an example, a commercially available aqueous solution of sodium silicate called water glass, or a solution obtained by further diluting it, can be used.

The quick-setting agent may be mixed with the refractory fine powder and added. For example, a refractory fine powder having a size of 1 mm or less is externally applied to the quick-setting agent and mixed at about 100% by mass. The refractory fine powder here can be selected and used from the materials exemplified above as the refractory aggregate, for example.

FIG. 1 is an image diagram of an example of spraying using a spray nozzle. An amorphous refractory that has been kneaded in advance is sent out to a pressure feed pipe (5) by a pressure feed pump (not shown) such as a piston pump, a squeeze pump, or a rotary pump, and a quick-setting agent connected to the nozzle (1) or its vicinity. A quick-setting agent is added to the amorphous refractory in the pressure feeding pipe (5) through the introduction pipe (2). The amorphous refractory is sprayed from the nozzle (1) after being added with the quick-setting agent, and is sprayed on the wall surface (3) to form a sprayed construction body (4).

Compressed air is introduced at the same time as the quick-setting agent from the quick-setting agent introduction pipe (2) in order to eject the amorphous refractory. The introduction of compressed air is not limited to this, and may be performed, for example, from the rear of the connecting portion of the quick-setting agent introducing pipe (2).

The present invention is characterized by the material of the amorphous refractory in which the amorphous refractory is kneaded in advance and sprayed by adding a quick-setting agent just before spraying. Is not limited to the above.

[0041]

EXAMPLES Examples of the present invention and comparative examples thereof will be shown below. Tables 1 and 2 show the amorphous refractory composition used in each example,
It is a kneading water content, a quick-setting agent, and the test result. In the construction, the amorphous refractory that was previously kneaded with a vortex mixer was pressure-fed with a piston-type pressure-feeding pump, and was sprayed onto the vertical wall of the refractory.

Each test except the actual machine test was measured by spraying on a wall surface at room temperature. Scratch resistance and corrosion resistance are
The test piece cut out from the construction body was dried at 110 ° C. for 24 hours and then measured.

Calcium lactate as a binder was manufactured by Fuso Chemical Industry. As the aluminum lactate, a trade name “Taxeram M-160P” manufactured by Taki Chemical Co., Ltd. was used.

As the quick-setting agent, a sodium silicate aqueous solution, a potassium silicate aqueous solution, and a sodium aluminate aqueous solution were used. Both were 40 mass% aqueous solutions. The amount added to amorphous refractories is
The external refractory (excluding the kneading liquid) was 0.2 to 0.3% by mass based on the solid content.

As a test of chipping resistance, the residual line change rate and the generated stress were measured. The residual line change rate was calculated by calculating the difference between the dimension before heating and the dimension after heating at 1400 ° C. for 3 hours as a percentage of the dimension before heating. If the test value is negative due to contraction, peeling damage is likely to occur.

With respect to the generated stress, the stress generated when heated in a restrained state was measured using a load cell. Test value is 14
The generated stress at 00 ° C., the smaller the numerical value, the smaller the generated stress, and the excellent resistance to chipping due to the stress absorbing ability.

Corrosion resistance was shown by an index with the corrosion loss dimension of Comparative Example 1 being 100, which was measured by a rotary erosion test using molten steel as a solvent in each example of Table 1. In each of the examples in Table 2, the erosion size was measured by a rotary erosion test using hot metal as a solvent, and the erosion size of Comparative Example 5 was shown as an index of 100. The smaller the value, the better the corrosion resistance.

In the adhesion test, the adhesion rate of the irregular shaped refractory on the wall surface was obtained.

The workability was comprehensively evaluated from the fluidity of the spray material in the material pressure pipe and the degree of blockage of the pressure pipe.
It was displayed in four stages from ~ D. A is the most workable and D is the least workable.

The curing speed was 2 when the compression strength of the sprayed product was 2.
The time to reach MPa was measured. The shorter the time, the faster the curing speed.

The actual machine test was carried out by spraying and repairing a 250t molten steel ladle. The lining material of the molten steel ladle to be repaired is an alumina-magnesia amorphous refractory. The number of times of use until the sprayed construction body was peeled off was obtained.

[0052]

[Table 1]

[Table 2] Table 1 is an alumina-magnesia amorphous refractory material. On the other hand, Table 2 shows alumina-silicon carbide amorphous refractories.
From the results shown in Tables 1 and 2, all of the examples of the present invention have excellent adhesion and scratch resistance, and have a fast curing rate. This chipping resistance can also be confirmed from the actual machine test results. Furthermore, it has no discoloration in terms of corrosion resistance and workability.

Further, in the examples of the present invention, the workability is not significantly reduced even when the amount of the organic short fibers added is large. The one using alkali silicate as the quick-setting agent is more excellent in adhesiveness than other examples.

On the other hand, Comparative Examples 1 and 5 use aluminum lactate, which has a high stress generated and is inferior in scratch resistance, and has a slow curing rate.

In Comparative Examples 2 and 6, alumina cement was used, and although the generated stress was low, the peeling resistance was poor due to residual shrinkage. It also has poor corrosion resistance.

Comparative Examples 3 and 7 use alumina cement and have a relatively large amount of organic short fibers, and are poor in adhesion, corrosion resistance and workability.

Comparative Examples 4 and 8 in which the amount of calcium lactate used was too large are inferior in chipping resistance due to residual shrinkage. Also, it is inferior in corrosion resistance.

FIG. 2 shows Example 1 of the product containing calcium lactate.
7 is a graph showing the relationship between the addition amount of calcium lactate and aluminum lactate and the stress generated by an irregular shaped refractory for Comparative Example 1 of the aluminum lactate-added product. The method of measuring the generated stress was the same as the method shown in the above-mentioned Example.

Although the reduction of the generated stress has an effect of improving the chipping resistance of the amorphous refractory, it can be confirmed from this graph that the addition of calcium lactate acts to reduce the generated stress.

In the above examples, the wall surface to be constructed was carried out at room temperature, but the method of the present invention can obtain the same effect on the wall surface in a high temperature state such as hot repair of the furnace wall. it can.

[0061]

As described above, the irregular refractory material according to the present invention has the adhesion, peeling resistance and corrosion resistance required for spraying. Especially by improving the peeling resistance,
Its durability is significantly improved compared to conventional materials. As a result, according to the present invention, it is possible to expect a reduction in the number of spraying construction steps and the amount of material used, and an improvement in the operating rate of the equipment to be constructed.

[Brief description of drawings]

FIG. 1 is an image diagram of a wet spraying construction example of the present invention.

FIG. 2 is a graph showing the relationship between the addition amount of calcium lactate and aluminum lactate and the stress generated in an amorphous refractory material.

[Explanation of symbols]

1 nozzle 2 Quick-setting agent introduction pipe 3 wall surfaces 4 Spraying construction body 5 pressure pipe

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Shoichi Itose             1-3-1 Niihama, Arai-cho, Takasago, Hyogo Prefecture             Kurosaki Harima Co., Ltd.             Shape factory F-term (reference) 4G033 AA02 AA10 AA17 AB02 AB21                       AB27 BA02                 4K051 LA02 LA11

Claims (6)

[Claims] 1. An amorphous refractory in which a pre-kneaded amorphous refractory is sprayed by adding a quick-setting agent just before spraying, and calcium lactate is added to 0.01% of calcium lactate with respect to 100% by mass of the refractory aggregate.
-3% by mass and a dispersant are added to the amorphous refractory for wet spraying. 2. The amorphous refractory material for wet spraying according to claim 1, wherein the quick-setting agent is an alkali silicate. 3. The amorphous refractory for wet spraying construction according to claim 1 or 2, further comprising 2% by mass or less of organic short fibers with respect to 100% by mass of the refractory aggregate. 4. A kneading agent is added after kneading an irregular-shaped refractory made by adding 0.01 to 3% by mass of calcium lactate and a dispersant to 100% by mass of the refractory aggregate, and immediately before spraying. Wet spraying method of spraying. 5. The wet spraying method according to claim 4, wherein the quick-setting agent is an alkali silicate. 6. The wet spraying method according to claim 4, wherein the organic short fibers are further added in an amount of 2% by mass or less with respect to 100% by mass of the refractory aggregate.