JPH1017374A - Monolithic refractory material for wet hot-gunning method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide the refractory material that is capable of securing a prescribed flowability of it even at the time of using a smaller amount of water and also, capable of securing good adhesion of it to the wall surface of a structure without adversely affecting corrosion resistance of the material even in a >=400 deg.C high temp. region, in a wet hot-gunning method which enables good workability and inhibition of dust generation. SOLUTION: This refractory material comprises a binder and refractory aggregate consisting of one single compound selected from among MgO, CaO, Al2 O3 , SiO2 , etc., or a combination of at least two of these compounds. At this time, the aggregate contains at least 10 to 35wt.% of a refractory material having <=45μm particle size and the binder contains at least two orthophosphates each in a concn. in the range of 0.1 to 5wt.% and also contains an anhydrous alkali silicate in a concn. in the range of 0.1 to 5wt.%.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improved refractory material for wet spraying which is hot-worked on the surface of a structure such as various industrial furnaces.

[0002]

2. Description of the Related Art Conventionally, converters, electric furnaces, degassing devices (R
H), a method called "wet spraying method" is a method of applying an amorphous refractory to the surface of a structure including various industrial furnaces such as a ladle and a tundish. This method ensures the fluidity of the amorphous refractory material,
In this method, sufficient water is added to the amorphous refractory material to make it into a slurry state, that is, a slurry state, and this fluid is sprayed from a nozzle onto a work surface.

[0003] As another spraying method, Mg
O, CaO, Al ₂ O ₃ , SiO _{2 and the} like as a main component of the clinker as an aggregate, silicate, phosphate, mixed powder using a cement or the like as a binder is transported to a predetermined position by air, Immediately before blowing out the mixed powder from the nozzle, a `` dry spraying method '' in which water is added to the mixed powder and spraying is performed, or a material obtained by finely pulverizing clinker similar to that used in the dry spraying method, and a flux, A method of spraying the mixed powder while melting it with a flame, such as the "flame spraying method", or baking a refractory material with tar, pitch, thermosetting resin, etc. by dropping or pouring. There is a "baking method" which is a method of construction.

The dry spraying method, which is a well-known method, involves kneading the mixed powder refractory and water immediately before spraying a powdery amorphous refractory onto a wall surface. Kneading is not enough, so that dust is often generated, the working environment is not preferable, and it is difficult to clearly confirm the construction position and construction state during construction work, and the workability is poor. is there. In addition, the flame spraying method can obtain a dense construction body for non-aqueous work, but on the other hand, requires a large-scale device such as a flame generator, and further needs to improve the fusibility by the flame. As a result, the amorphous refractory to be used becomes a fine powder, and generates dust as in the case of the dry spraying method, which has a disadvantage that the working environment is not preferable and the workability is poor. Furthermore, since the baking method can be performed simply by charging a refractory material, the work is simple, but when an organic flux such as tar, pitch, and resin is added, smoke is generated, and the working environment is not preferable. This method has a drawback that it takes a long time for baking, and the like. This method is mainly used for floor construction, and is rarely used for other construction.

However, in the wet spraying method, since the powdery amorphous refractory material is previously kneaded with water, no dust is generated, the working environment is deteriorated, and the construction position and construction state are clearly identified. There is no drawback that it is difficult to perform and the workability is inferior. Also, a large-scale device such as a flame generating device is not required. Furthermore, there is no drawback such as a long time required for baking as in the baking method, and it can be effectively used for construction of a vertical wall surface other than a floor surface, a ceiling wall surface, and the like.

[0006]

However, in this wet spraying method, an amorphous refractory material is kneaded with a sufficient amount of water to form a slurry in order to secure the fluidity of the construction material, and the refractory material in the slurry state is used. Since the spraying on the construction surface generally results in too much water contained in the refractory material, it is difficult to have a large shape-retaining force, and it is not possible to obtain a dense construction body. is there. In addition, when the material in the slurry state is injected into the hot working body, the moisture in the material starts to evaporate rapidly. As a result, the adhesion of the construction material is significantly impaired by the vapor pressure of the water.
There is a problem that it is difficult to perform hot work at 0 ° C. or more.
For this reason, in the wet spraying method with good workability in which the generation of dust is suppressed, it is possible to secure a predetermined fluidity even with a low moisture content, and it is good for the structure wall even in a high temperature range of 400 ° C. or more. Thus, there is a demand for a hot working material for wet spraying that can ensure a proper adhesion and does not impair the corrosion resistance of the working material.

[0007]

SUMMARY OF THE INVENTION The present invention relates to an amorphous refractory material for use in wet hot spraying, comprising Mg
O, CaO, Al ₂ O ₃ , SiO _2, etc., alone or in combination of two or more thereof, a refractory aggregate and a binder, wherein the aggregate has a particle size of 45 μm or less. A refractory material having an amount of 10 wt% to 35 wt%, wherein the binder comprises at least two orthophosphates in the range of 0.1 wt% to 5 wt% each, and an anhydrous alkali silicate of 0.1 wt% to 5 wt%. %, It is possible to secure a predetermined fluidity even with a low water content, and to ensure good adhesion to the structure wall even in a high temperature range of 400 ° C. or more, and An amorphous refractory material for wet hot spraying, which does not impair the corrosion resistance of the construction material, is provided.

[0008]

Embodiments of the present invention will be described below. The hot spray refractory material for wet spraying of the present invention is basically composed of the same aggregates and binders as those used in conventional dry spraying methods, for example. However, the components constituting them are different from the conventional component compositions.

In the present invention, as the aggregate, MgO,
A refractory material made of CaO, Al ₂ O ₃ , SiO ₂ or the like alone or in combination of two or more thereof is used.
This aggregate is composed of, for example, three grades. That is, those having the coarsest diameter of, for example, about 3 mm to 1 mm, those having a substantially powdery diameter of 1 mm to 45 μm, and those having a fine powder state of 45 μm or less. Here, as a result of experiments conducted by the applicant, it has been found that the aggregate in the state of fine powder having a size of 45 μm or less is an essential element, and that the amount is desirably 10 wt% to 35 wt%. If the amount of the fine powder is less than 10 wt%, the adhesiveness of the material to the construction surface is poor, and it is difficult to secure the material adhesion particularly in the hot state.
It has been found that when the temperature exceeds the limit, the refractory material sticks to the inner surface of the hose and becomes a factor that hinders the fluidity of the refractory material.

As the binder, at least two kinds of orthophosphates containing, for example, sodium phosphate monobasic, potassium phosphate monobasic, calcium phosphate monobasic, etc., are each selected in the range of 0.1 wt% to 5 wt%. An alkali silicate such as anhydrous sodium silicate, anhydrous potassium silicate, anhydrous lithium silicate or the like having a low dissolution rate in water is similarly selected in the range of 0.1 wt% to 5 wt%, and both are added and blended. It is.

Here, the selected two or more orthophosphates particularly function as a main binder, and the spraying material of the present invention uses the base of the metal ion of the two or more orthophosphates. The substitution provides an excellent hardening effect. Such a curing reaction is carried out by a conventional binder of a dry spray material comprising, for example, a known sodium hexametaphosphate and slaked lime (see Japanese Patent Publication No. 55-6598).
In addition, it exhibits a very slow curing action, that is, a slow curing property, and can provide sufficient curing strength for retaining the shape of the amorphous refractory material.

Further, an alkali silicate having a low dissolution rate in water particularly functions as a binding aid, and the alkali silicate serving as a binding aid is hot after adhering to the wall of the structure. Thus, the silicate glass exhibits strength, thereby providing a function to supplement the shape retention.

In the present invention, preferably, ultrafine silica powder having an average particle size of 10 μm or less is contained in an amount of 0.1 wt% or less.
It is preferable to add in the range of 5 wt%. This ultrafine silica powder functions as a water reducing agent, and the addition of the water reducing agent makes it possible to provide very good fluidity in a hose even with low moisture.

In the present invention, desirably, various organic acids such as malic acid and citric acid, various inorganic acids such as boric acid and sulfamic acid, chlorides such as magnesium chloride and sodium chloride, sulfates such as magnesium sulfate and the like. Is preferably selected and added. These various organic acids, various inorganic acids, chlorides, sulfates, and the like function as a curing regulator, and since the curing regulator can adjust the acceleration or delay of curing, the material residence time in the hose It is preferable to add as appropriate according to needs. In addition to the above, known additives can be added to irregular refractories such as organic and inorganic fibers, refractory clays, and carbonates.

[0015]

EXAMPLES Specific examples will be described below. All of these examples are based on the 800 ° C. hot spray test, and the transport distance of the amorphous refractory material by the hose is 20 meters in each case. In each example,% is shown by weight% (wt%), time is (seconds), spraying method is wet or dry, and rotary slag erosion test erosion index is C / The degree of erosion when the basic slag of S = 3.0 was tested under the test conditions of 1650 ° C. × 3 hours was 100 in Example 1 according to the present invention.
It is shown by the index when.

Embodiment 1 This embodiment embodies the present invention. The material composition is: MgO clinker (3 mm to 1 mm): 30% MgO clinker (1 mm to 45 μm): 50% MgO clinker (45 μm or less): 15% Sodium monophosphate: 0.5% Potassium monophosphate: 1.5 % Sodium silicate anhydrous: 2.0% Silica fine powder: 1.0% Spraying method: wet Addition of water: 13% Curing time: 75 800 ° C hot spraying workability: extremely good 800 ° C hot spraying dust generation state : Extremely low 800 ° C hot spray discharge property: Extremely good Rotary slag erosion test Melting index: 100

Example 2 This example is based on the use of a known binder. The material composition is as follows: MgO clinker (3 mm to 1 mm): 30 MgO clinker (1 mm to 45 μm): 35 MgO clinker (45 μm or less): 28 No. 1 sodium silicate: 1.0 anhydrous sodium silicate: 1.0 sodium hexametaphosphate : 2.0 Silica fine powder: 1.0 Slaked lime: 2.0 Spraying method: Dry type Water addition amount: 15% Curing time: 25 800 ° C hot spray workability: Extremely good 800 ° C hot spray dust generation state: Many 800 ° C hot spray dischargeability: extremely good Rotary slag erosion test Melting index: 99

Embodiment 3 This is an embodiment of the conventional wet spraying method, and it is said that hot working at 400 ° C. or more is difficult. The material composition is as follows: MgO clinker (3 mm to 1 mm): 30 MgO clinker (1 mm to 45 μm): 40 MgO clinker (45 μm or less): 24 No. 1 sodium silicate: 2.0 refractory clay: 2.0 paper powder: 5 Organic acid: 0.5 Spraying method: Wet method Water addition amount: 22% Curing time: No curing 800 ° C hot spraying workability: No work due to peeling 800 ° C Hot spraying dust generation state: Extremely low 800 ° C Hot-spraying dischargeability: Very good Rotary slag erosion test Melting index: 135

Embodiment 4 This is an embodiment in which MgO clinker (45 μm or less) is intentionally introduced in a large amount. The material composition is as follows: MgO clinker (3 mm to 1 mm): 20 MgO clinker (1 mm to 45 μm): 30 MgO clinker (45 μm or less): 45 Sodium phosphate monobasic: 1.0 Potassium phosphate monobasic: 1.0 Sodium silicate anhydride : 2.0 Silica fine powder: 1.0 Spraying method: Wet method Water addition amount: 13% Curing time: 50 800 ° C hot spraying workability: Good 800 ° C hot spraying dust generation state: Low 800 ° C hot spraying Dischargeability: Many irregularities occurred Rotary slag erosion test Melting index: 100

From the above examples, it was found that when the content of MgO clinker (45 μm or less) as an aggregate exceeds 35 wt% (Example 4), the flowability in the hose was hindered and the dischargeability was poor. doing. The reason why the ejection property is good in the second embodiment using the known binder configuration is that the spraying method in the second embodiment is a dry type. However, as described above, the dry method generates a large amount of dust, which is not preferable in the working environment. Also,
In Example 3, which is a conventional wet method which does not contain at least two or more orthophosphates as a binder and does not have an anhydrous alkali silicate, the generation of dust is small and the discharge property is good, but the fire resistance is high. The material did not cure, resulting in delamination.

On the other hand, the embodiment 1 is a wet spraying method in which the generation of dust is suppressed and the workability is good, and the amount of water added is as very low as 13 wt%, and the curing time is 75 seconds and the predetermined time is required. It can provide excellent dischargeability to secure the fluidity of the material, and secures good adhesion to the furnace wall even in a high temperature range of 800 ° C. and does not impair the corrosion resistance of the construction material. It was possible to provide an excellent hot refractory construction material for wet spraying.

[0022]

As shown in the first embodiment, according to the present invention, the curing time can be appropriately adjusted according to the length of the hose, and the amorphous refractory material is transported through the hose. During stagnation, it has sufficient fluidity, is discharged from the tip of the injection nozzle, adheres to the furnace wall, and hardens rapidly. Became possible.

Further, spraying can be performed with the same moisture content as that of the dry spraying method, and the deterioration of corrosion resistance, which is a drawback of the conventional wet spraying method, is also improved. Furthermore, considering the mechanism of the initial stage of adhesion of the refractory material to the construction surface during construction, in the conventional dry spraying method, after the furnace wall is cooled by the added water in the initial stage of adhesion, first the fine powder forms the adhesion nucleus, Thereafter, a mechanism is employed in which the sprayed material swells around the adhesion nucleus. For this reason, the internal structure of the construction body immediately after the material is attached is considerably different from the originally expected grain size configuration, and the intended original material properties are not exhibited.

On the other hand, in the wet spraying method of the present invention, the refractory material and water are kneaded in advance so that they are ejected and adhered in a united state with the intended original particle size composition. As a result, it is possible to contribute to the improvement of the durability by exhibiting the inherent characteristics of the refractory material, and to reduce the dust that has been a problem of the conventional dry spraying and thermal spraying without impairing the corrosion resistance of the refractory material. The generation can be considerably reduced.

Claims (7)

[Claims] 1. An amorphous refractory material used for wet hot spraying, comprising MgO, CaO, Al ₂ O ₃ , S
The binder comprises: a refractory aggregate made of iO ₂ or the like alone or a combination of two or more of them; and a binder, wherein the refractory aggregate has a refractory material having a particle size of 45 μm or less in an amount of 10 wt% or less. An amorphous refractory material for wet hot spraying, comprising 35 wt%, wherein the binder is composed of at least two kinds of orthophosphates and anhydrous alkali silicate. 2. The binder contains 0.1 wt% to 5 wt% of each of at least two kinds of orthophosphates including sodium first phosphate, potassium first phosphate, calcium first phosphate and the like.
wt% and 0.1 wt% to 5 wt% of anhydrous alkali silicate
%. The amorphous refractory material for wet hot spraying according to claim 1, wherein the amorphous refractory material is formed by adding and mixing%. 3. The amorphous refractory material for wet hot spraying according to claim 1, wherein the alkali silicate is sodium silicate anhydride. 4. The amorphous refractory material for wet hot spraying according to claim 1, wherein ultrafine silica powder having an average particle diameter of 10 μm or less is added in an amount of 0.1 wt% to 5 wt%. . 5. Addition of at least one or more of various organic acids such as malic acid and citric acid, various inorganic acids such as boric acid and sulfamic acid, chlorides such as magnesium chloride and sodium chloride, and sulfates such as magnesium sulfate. The amorphous refractory material for wet hot spraying according to claim 1, wherein the refractory material is made of a material. 6. The irregular shaped refractory for wet hot spraying according to claim 1, wherein additives such as organic and inorganic fibers, refractory clay, carbonate and the like are added. material. 7. As an aggregate, M having a particle size of 3 mm to 1 mm is used.
30 wt% of gO clinker and M of 1 mm to 45 μm
50 wt% of gO clinker and 45 μm or less of MgO
15 wt% of clinker, and 0.5 wt% of sodium phosphate monobasic, 1.5 wt% of potassium phosphate monobasic, and 2 wt% of anhydrous sodium silicate as binders.
2. The irregular shaped refractory for wet hot spraying according to claim 1, further comprising, as a water reducing agent, 1 wt% of ultrafine silica powder having an average particle diameter of 10 μm or less. 3. Material.