JPH0610102B2 - Powder binder composition - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a powder binder composition mainly used for powdery amorphous refractory materials (hereinafter referred to as “dry material”). From the principle of the present invention, it can be applied to building materials and other cured products of heat resistant materials.

2. Description of the Related Art (Description of Dry Material) Dry materials are often used as lining materials for electric induction heating type crucible furnaces that melt cast iron, cast steel, or non-ferrous materials (copper alloys, etc.). In this case, the lining thickness required between the furnace shell (as the lining thickness in the crucible furnace,
Set a gap of 100 mm to 150 mm), install a metal frame inside the furnace, and put dry material into the gap,
Shake the metal frame with a vibration motor, or solidify the input material with a stick with a vibrator attached, and fill it.
In this state, the molded body does not have a sufficiently large strength, so the metal frame is heated and the binding material (boric acid is used in most cases) contained in the dry material (molded body). The bond strength is obtained by melting and the metal frame is removed. Alternatively, heat up to the temperature at which the metal frame melts and dry the material
Is sintered and the metal frame is also processed.

As can be seen from this example, the dry material is the same as other amorphous refractories in that the dry material is composed of a heat-resistant aggregate which is a main component and a binder that bonds them. , Such as ramming refractory and plastic refractory, it is a powder without water or liquid binder, for example, castable refractory (refractory concrete). A major feature is that the powdered material is used as it is in a furnace without adding water and kneading with a mixer.

Further, the dry material is similar in that it is installed by installing a metal frame and inserting the refractory material into the gap, but like the plastic refractory material and the ramming refractory material, after stamping and casting the castable refractory material. Unlike the one where the strength of the molded body is developed after the construction and the work excluding the metal frame can be carried out, the strength must be developed by heat treatment and the metal frame must be removed, which is a big difference with other amorphous refractories. There is a difference. By the way, in order to remove the metal frame, it is necessary for the strength of the molded body to have a compressive strength of at least 1 to ² kg / cm ² , and in view of safety, 5 kg / cm ² is preferable. It has been obtained as knowledge.

(Characteristics of dry materials) Based on the results of the above crucibles, even if the dry materials contain a small amount of crystal water in the binder, unlike the other irregular shaped refractory materials, the dry materials contain a large amount of water, decomposition and dissipative components. Many benefits are found because it is not included. First of all, since it does not contain water etc., it does not lose its product value due to freezing during storage, and the reaction does not proceed inside the material at high temperature and it becomes hard and it cannot be installed. The point is that it is possible to significantly reduce the construction-time loss that makes work impossible due to deterioration due to temperature changes, and the economic loss, which are claims that often occur with other amorphous refractories. Next, since it does not contain water or the like, it is not necessary to dry it to remove water in the molded body. For example, the temperature can be raised by 10 times or more as compared with the case of castable refractory and it can be used for operation. It is possible to bring it into a state and bring about a great economic merit in terms of energy saving and shortening of the construction period which can shift to operation in a short period of time.

Furthermore, for example, castable refractory is a prominent example, but when heating and heating for drying, the water remaining inside the molded body becomes water vapor, destroying the molded body at once and scattering fragments That is, so-called steam explosion (explosion) often occurs. This leads to a loss that hinders the operation, and most importantly, it causes a personal injury, which is a major issue in safety management.

In the case of a dry material, in principle and as a track record, there is a great advantage in being a material that does not cause such a problem.

(Bonding material of dry material) Since the dry material is formed by molding in a metal frame without containing water, and since the strength is developed by heating from the metal frame after that, as a bonding material for this, Available as a powder.

Can be stored as powder.

It is non-toxic and safe to handle.

Bond strength develops at the lowest possible temperature.

Therefore, boric anhydride, boric acid and borate have been mainly selected and used conventionally. The dry material using this kind of binder has a lower melting point (boric anhydride; compared to the case where another powder binder, for example, a silicate binder represented by powdered sodium silicate) is used. About 450 ° C, sodium silicate No. 2; about 700
℃), the binder gradually begins to form a liquid phase 35
It can be solidified by heating at a low heating temperature of about 0 ° C. and can have the strength necessary for removing the metal frame. On the other hand, other inorganic powder binders can exhibit a large strength when dissolved in water and reacted as a solution, but at a high temperature of 700 ° C. or higher at which a liquid phase begins to be generated in the powder state. The strength cannot be obtained without heating.

Problems to be Solved by the Invention As described above, the dry material using the borate powder binder, which is highly effective in strength development at low temperature, has a high corrosion resistance when it comes into contact with the molten metal or the molten metal stream of slag at high temperature. Problems such as deterioration occur. Since this kind of powder binder has a low melting point itself, it is not only dissolved in the molten metal flow and leads to melting damage of the dry material, but also the binder reacts with a part of the aggregate to cause glass engineering. It is considered that a borosilicate glass-like low-melting component is generated to accelerate the melting loss, but in any case, there is a great limitation in that the corrosion resistance to the molten metal flow cannot be improved.

The one using the borate-based binder has an excellent initial strength at low temperature from the viewpoint of strength, but vitrification progresses, so that the strength during hot is lowered, and therefore it is washed by the molten metal flow. Lead the result.

Further, the formation of a low-melting component or a glass phase, as a matter of course, causes the spalling destruction of the dry material lining refractory due to the thermal history of heating and cooling of the furnace body during the operation. It becomes a factor that hinders the improvement of the fire resistance of the lining material.

Means for Solving the Problems As described above, there is a need for an alternative to the borate binder that limits the durability of the dry material due to the progress of vitrification. Therefore, we focused on the phosphoric acid bond used in plastic refractory materials and ramming refractory materials in terms of high corrosion resistance and high hot strength at high temperatures.

Phosphoric acid bond is a method in which phosphoric acid and activated alumina are used as a binder, aluminum phosphate is gradually generated, and polycondensation is performed by heating to increase strength. There is also a method of adding aluminum phosphate as a binder to the aggregate from the beginning. Of course, the occurrence of spalling breakage due to the progress of vitrification can also be suppressed. However, although powdered aluminum phosphate can also obtain phosphoric acid, it cannot be used as a binder for a dry material because, in the powdered state, as in the case of the powdered silicate binder, it cannot be used at a low temperature. This is because the strength at 1 does not appear at all. This is because the melting point is very high (a melting point of 1700 ° C. or higher in the case of AlPO ₄ ).

As a result of examining various powder binders in combination with aluminum phosphate, the alkali metal salt of phosphoric acid and ammonium phosphate salt were added to aluminum tripolyphosphate, and when combined, the low temperature strength of the dry material was developed. It was discovered that this combination can be used as a binder for dry materials.

That is, the present inventors have found that, as a function that the dry material should have, normally, at room temperature, at least 80 ° C. or lower, the powder binder does not change and is stable, and when mixed with refractory powder particles. Stability and storability at the same temperature, and usually in the low temperature range (for example, 1
(00-500 ° C), the reaction product does not vitrify (amorphous), and the reaction product exhibits the property of being difficult to vitrify even in a high temperature range and maintains the spall resistance. In addition, in view of its corrosion resistance, it was considered that it is desirable that, in addition to not having a vitrified structure, a phosphate bond is easily generated.

As a result of various studies on dry materials capable of satisfying these various requirements, the present inventors have found that an alkali metal salt of orthophosphoric acid or condensed phosphoric acid or an ammonium salt (hereinafter referred to as “phosphate salt”).
And a series of systems comprising aluminum dihydrogen tripolyphosphate satisfy these requirements.

The present invention will be described in more detail.

In other words, in the low temperature range that is often used,
A phosphate that causes phosphoric acid condensation is used. These phosphates are excellent in the ability to form a phosphoric acid bond, but at the same time, they are vitrified (amorphous) and have major problems in corrosion resistance, spall resistance and the like.

On the other hand, aluminum dihydrogen tripolyphosphate is used for the other composition. Aluminum dihydrogen tripolyphosphate has a chemical formula of H ₂ AP ₃ O ₁₀ · 2H ₂ O, has extremely high acidity, is poorly soluble in water, has a melting point of about 1200 ° C.,
In addition, the possessed protons are alkali metal ions,
Alternatively, it is easily ion-exchanged with a cation such as ammonium ion. For example, as an example of the present invention, taking sodium phosphate as an example, 2NaH ₂ PO ₄ .2H ₂ O + H ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ + Na ₂ AP ₃ O ₁₀ + 6H ₂ O ( The reaction proceeds as in 1) and phosphoric acid is released. That is,
Since the phosphate and aluminum dihydrogen tripolyphosphate are dry-mixed, the so-called ion exchange reaction does not occur at room temperature, so that they exist in a stable state as they are.

However, when these are heated, the above reaction occurs due to activation due to temperature (so-called low temperature range in the so-called refractory material), and as a result, phosphoric acid is generated. The generated phosphoric acid, of course, binds with phosphoric acid, but since it is a liquid, an apparent mixture of these powders is in a molten state. This melting temperature is much lower than the melting temperature of the single resistance of each composition. That is, the binding force is developed in the low temperature range. Also noteworthy here is that sodium tripolyphosphate sodium soda (generally aluminum tripolyphosphate alkali salt) produced as a result of the reaction retains crystallinity and is extremely difficult to vitrify (hard non-crystalline). Quality, and therefore has a very favorable effect on corrosion resistance and spall resistance. Further, it is well known to use aluminum dihydrogen tripolyphosphate as a refractory material binder in a high temperature range, and it can exhibit properties as a binder in a high temperature range where vitrification is most likely to proceed.

As described above, it has been found that by using a mixture of a phosphate and aluminum dihydrogen tripolyphosphate, it is possible to manufacture the extremely excellent dry material while making full use of the characteristics of the simple substance itself and compensating for the drawbacks. The aluminum dihydrogen tripolyphosphate may be used by appropriately mixing the first aluminum phosphate.

As shown in Examples described later, as the phosphate, not only orthophosphate, but also condensed phosphate such as pyrophosphate, tripolyphosphate, and hexametaphosphate can be used. As the cation species, alkali metal ions such as sodium and potassium and ammonium ions can be used.

Further, these phosphates can be used alone or in combination of several kinds of phosphates.

The method for producing aluminum dihydrogen tripolyphosphate used in the present invention is well known. For example, as shown in JP-B-55-50884, the molar ratio of P ₂ O ₅ / A ₂ O ₃ is 5 or less, and 1 kg of air containing a raw material with a degree of condensation of 3 or less
Therefore, it can be obtained by firing in a hot steam atmosphere of 200 to 650 ° C. containing 0.5 kg or more of water.

In preparing the dry material of the present invention, the above-mentioned various phosphates and aluminum dihydrogen tripolyphosphate may be mixed in advance, or may be mixed immediately before use. However, when mixing, if the temperature rises too much due to frictional heat, for example, by passing through a crusher, a part of it may soften and melt, so care must be taken.

In order to use the dry material of the present invention for an amorphous refractory, silicon carbide, alumina, magnesia, aluminum silicate,
Used with refractory aggregates such as chromite, silica, graphite, zirconia, and zircon. The mixing ratio of aggregate and dry material is
Since it greatly varies depending on the particle size, particle shape, particle size distribution, etc. of the aggregate used, it is necessary to experimentally determine in advance the mixing ratio that gives the highest strength.

Next, the amorphous refractory material obtained by mixing the dry material and the aggregate of the present invention is put in a mold having a desired shape, and then densified by an appropriate vibration method, pressing method, stamping method, injection method with an injection machine, or the like. To convert. The densified refractory is heated and then fired to bond the aggregate. Any heating method may be used, but the simplest method is to use a gas burner from the outside of the mold.
After cooling, the mold is demolded to obtain the desired refractory molded body.

Action, Example It has already been mentioned that aluminum dihydrogen tripolyphosphate withdraws sodium from sodium phosphate and isolates phosphoric acid as shown in reaction scheme (1). For other phosphates, a reaction formula similar to reaction formula (1) can be written. That is, Na ₂ HPO ₄・ 12H ₂ O + H ₂ AP ₃ O ₁₀・ 2H ₂ O → H ₃ PO ₄ ＋ Na ₂ AP ₃ O ₁₀ ＋ 14H ₂ O (2) 2Na ₃ PO ₄・ 12H ₂ O + 3H ₂ AP ₃ O ₁₀・2H ₂ O → 2H ₃ PO ₄ ＋ 3Na ₂ AP ₃ O ₁₀ ＋ 30H ₂ O (3) Na ₂ H ₂ P ₂ O ₇ ＋ H ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ ＋ Na ₂ AP ₃ O ₁₀ ＋ H ₂ O (4) Na ₄ P ₂ O ₇ ＋ 2H ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ ＋ 2Na ₂ AP ₃ O ₁₀ ＋ 3H ₂ O (5) 2Na ₅ P ₃ O ₁₀ ＋ 5H ₂ AP ₃ O ₁₀・ 2H ₂ O → 6H ₃ PO ₄ ＋ 5Na ₂ AP ₃ O ₁₀ ＋ 6H ₂ O (6) (NaPO ₃ ) ₆ ＋ 3H ₂ AP ₃ O ₁₀・ 2H ₂ O → 6H ₃ PO ₄ ＋ 3Na ₂ AP ₃ O ₁₀ (7) 2NH ₄ H ₂ PO ₄ ＋ H ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ ＋ (NH ₄ ) ₂ AP ₃ O ₁₀ ＋ 2H ₂ O (8) (NH ₄ ) ₂ HPO ₄ ＋ H ₂ AP ₃ O ₁₀・ 2H ₂ O → H ₃ PO ₄ ＋ (NH ₄ ) ₂ AP ₃ O ₁₀ ＋ 2H ₂ O (9) 2 (NH ₄ ) ₃ PO ₄・ 3H ₂ O + 3 ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ ＋3 (NH ₄ ) ₂ AP ₃ O ₁₀ ＋ 12H ₂ O (10) 2KH ₂ PO ₄ ＋ H ₂ AP ₃ O ₁₀・ 2H ₂ O → 2H ₃ PO ₄ ＋ K ₂ AP ₃ O ₁₀ ＋ 2H ₂ O (11) Add a mixture of these phosphates and aluminum dihydrogen tripolyphosphate. For the evaluation of the binding force of when,
For the time being, from the viewpoint that a liquid phase is generated and sintered to develop strength, in order to observe the liquid phase generation state, a tablet of dry material is made and placed in an electric furnace to apparently soften and melt the bonded body. I checked the situation. As a result, as the phosphate, sodium dihydrogen phosphate dihydrate,
Tetrasodium pyrophosphate decahydrate, potassium dihydrogen phosphate, diammonium hydrogen phosphate, etc., as long as 30% or more is added to aluminum dihydrogen tripolyphosphate,
The apparent melting point decreases.

The alkali metal and ammonium salts of orthophosphoric acid and condensed phosphoric acid, when used in combination with aluminum dihydrogen tripolyphosphate, all soften and melt at the same temperature as the simple substance or at a temperature lower than that.

Specifically, sodium dihydrogen phosphate dihydrate softens and melts at an apparent temperature of 100 ° C.

From the apparent melting state, the combination for aluminum tripolyphosphate dihydrogen phosphate is the order of potassium dihydrogen phosphate, diammonium hydrogen phosphate, sodium dihydrogen phosphate dihydrate, the melting point is lowered, and the temperature is expressed. The effect (coupling strength) of is likely to increase.

On the other hand, when these melts were analyzed by X-ray diffraction, those having a mixed composition with respect to aluminum dihydrogen tripolyphosphate were not completely vitrified, and although they depend on the content of aluminum dihydrogen tripolyphosphate, The diffraction line of No. 2 showed a high peak at 2θ = 11.2 °, which proved to be of a crystal composition.

It is considered that the mechanism of this apparent melting, in other words, strength development, is due to (1) to (11).

That is, Na ₂ AP ₃ O ₁₀ was obtained by the reaction of aluminum dihydrogen tripolyphosphate with potassium dihydrogen phosphate, diammonium hydrogen phosphate, sodium dihydrogen phosphate dihydrate, tetrasodium pyrophosphate decahydrate, etc. Generate, meanwhile,
The phosphoric acid that precipitates exerts strength.

Next, an example of a dry material using the bonding material of the present invention will be shown below, based on an aggregate for a trough material of an irregular shaped refractory used for tapping gutter of a blast furnace.

The raw material composition of the tested dry materials is as shown in Table 1.

Comparative Example 1 does not contain any binder, Comparative Examples 2-4
Is a binder used in a normal dry material (the addition amount of the binder is in a normal usage range, including both a small amount and a large amount), and Comparative Example 5 is other than the dry material. It is a typical example of the inorganic binder used in.

The main qualities of the raw materials used in Examples and Comparative Examples are as follows.

Electrofused alumina: A ₂ O ₃ content is 99%, α-A ₂
A commercial product made of O ₃ (corundum) crystal and crushed to each precision of 5 to 1 mm, 1 mm or less, and 0.3 mm or less.

Temporary burn Alumina: in A ₂ O ₃ content of 99.8%, relatively low temperature range (about 1100 ° C.) fine crystalline produced by α-
A commercial product of finely divided alumina composed of A ₂ O ₃ crystals and having a particle morphology of 0.1 mm or less.

Silicon carbide: a commercial product having a SiC content of 85.6% and crushed to 0.1 mm or less.

Boric anhydride: An industrial commercial product containing 96.5% as B ₂ O ₃ and having an accuracy of 0.3 mm or less.

Powdered sodium silicate: SiO ₂ / Na ₂ O ₃ molar ratio is 2.5,
SiO ₂ content is 57%, Na ₂ O ₃ is 23%
%, A commercial product having a particle size distribution of 0.3 mm or less.

Aluminum dihydrogen tripolyphosphate: Product name, K bond # 80 (manufactured by Teikoku Kako) Sodium dihydrogen phosphate: Special grade reagent potassium dihydrogen phosphate: Special grade reagent Aluminum dihydrogen phosphate: Special grade reagent The samples of Examples 1-8 and Comparative Examples 1-5 were prepared by mixing the formulations shown in Table 1 in a 20-volume laboratory V-type mixer to make about 15 kg each.

(Curing Strength Test) Each composition shown in Table 1 was put into an iron metal frame installed on a vibrating table having an electric vibrator attached to the bottom. The metal frame has a diameter of 50 mm and a height of about 50 mm, and has a split-type structure that can be divided into three parts so that a cylindrical molded body can be obtained after the end of vibration, and can be attached and detached to the vibrating table with bolts. Using.

After the sample mixture was put into the metal frame, an iron disk with a diameter of about 48 mm and a thickness of 10 mm was set on the sample as a drop lid to prevent the powder on the vibrating body from scattering. . Molding conditions are
The strength of vibration was such that a force of 5 G, which belongs to the middle level, was applied, and the vibration table was vibrated for 20 minutes to mold the specimen in the metal frame.

After molding, each specimen was removed from the vibrating table, and the whole metal frame was placed in a hot air circulation type electric drying oven at 100 ° C, 200 ° C.
The mixture was heat-treated at temperatures of 300 ° C. and 300 ° C., taken out 4 hours later, and cooled at room temperature. Then, the strength of each heat-treated sample under test excluding the metal frame was determined by an electric uniaxial pressurization compression tester.

The measurement results are shown in Table 2.

Sodium silicate as powder is ineffective at 300 ° C or lower. Boric anhydride has a high strength at 300 ° C., and the larger the addition amount, the greater the effect. The sample of the present invention develops strength by a heat treatment as low as 200 ° C. As in Example 1, aluminum dihydrogen tripolyphosphate alone has no effect, and the strength that can be deframed cannot be obtained unless it is used in combination with an alkali salt of phosphoric acid and the former is 70% or less.

(Spalling resistance) From the test results of the curing strength, a circle having an inner diameter of 100 mm was prepared for each of the mixed sample samples of Comparative Examples 2 and 4 and Examples 3 and 5-8, which are considered to be capable of developing the strength enough to be deframed at a low temperature. It was put into a columnar iron metal frame and was molded by applying vibration. This is an enlarged metal frame whose compressive strength was measured, and has the same structure. The molding conditions are also the same.

After heat treatment at 300 ° C., these molded bodies were deframed and inserted into a large electric furnace using a silicon carbide heating element, and the temperature was 10 ° C.
The temperature was raised up to 1400 ° C. at a rapid rate of / min, and heated and held there for 3 hours. After that, take it out of the furnace, put it in water as it is, cool it rapidly and leave it in water for 3 minutes, then take it out and immediately insert it into an electric furnace kept at 1350 ° C. and heat it rapidly for 30 minutes. did.

It was taken out again, put into water and cooled rapidly. A spalling test was performed by repeating such rapid heating and rapid cooling. The results are shown in Table 3.

In Comparative Examples 2 to 4, when observing the cross section, the more glassy boric acid is, the more glassy products are foamed, and it is recognized from the color tone that the silicon carbide is oxidized and whitened.

In the example, only slight hair cracks were generated, and the spall resistance was far superior to that in the comparative example.

(Hot Bending Strength) Comparative Example 3 was added to Examples 3, 5 to 8 in consideration of expression of sufficient strength capable of being deframed at low temperature and spall resistance, and hot bending strength was measured.

Take a portion of these mixture samples prepared earlier and
The area that can cover the upper surface of the metal frame by diverting the metal frame for casting castable refractory that can obtain a 40 × 40 × 160 mm prismatic molded body specified in SR 2553 and filling the metal frame with heaps Then, an iron plate having a thickness of 15 mm was placed and placed on the vibrating table, and the metal frame was vibrated and molded.

However, the metal frame was not fixed to the vibrating table, but a hand was placed on the iron plate cover to prevent the metal frame from moving due to vibration. The vibration conditions are the same as in the case of the curing strength test.

After vibrating, unnecessary material was cut off with a mortar trowel so as to be flat on the upper surface of the metal frame, and finished into a smooth surface.

Next, the metal frame was inserted into an electric furnace heated to 300 ° C., heat-treated for 2 hours, deframed, and the test molded body was taken out. Each test molded body was inserted into a hot bending test furnace using a silicon carbide heating element, and heated at a high rate of 10 ° C / min to 1450 ° C, which is the maximum temperature obtained in this type of furnace. After being held there for 1 hour, the strength was measured by placing it on a two-point support type bending strength measuring jig set in the furnace. Table 4 shows the results of the strength measurement during hot working at 1450 ° C.

In Comparative Examples 2 to 3 using boric anhydride, the hot strength is so small that it cannot be measured, but all of the Examples have the ability to maintain the strength at high temperature.

(Corrosion resistance test result) It has the strength that can be deframed at low temperature and has excellent spall resistance.
In addition, Examples 3 and 5 were found to have high hot bending strength.
8 to Comparative Example 3 of the conventional type, a corrosion resistance test against hot metal and slag was conducted.

Take a part of each test mixture sample prepared previously, and in the cross section, a trapezoid of bottom side x top side x height of 53 x 36 x 20 mm,
Each of them was filled in a metal frame having a split-type structure that can obtain a molded body having a length of 120 mm.

As in the case of hot bending strength measurement, the metal frame was filled up with a heap, the upper surface thereof was covered with an iron plate having a thickness of 15 mm, placed on a vibrating table, and the whole metal frame was vibrated. Since the metal frame is not fixed, the iron plate used for the cover was lightly pressed by hand to prevent it from moving on the vibration table.

After the vibration, the material protruding on the upper surface of the metal frame was cut with a mortar iron to finish it smoothly. Next, as in the case of hot bending strength measurement, the metal frame was heat-treated at 300 ° C. for 2 hours to cure the molded body and remove the metal frame.

These molded bodies were inserted into an electric furnace using a silicon carbide heating element, heated up to 1200 ° C. at a high rate of 10 ° C./min and held for 1 hour, then left to cool and taken out. Two in Example 3, two in Example 3, one in each of the others, for a total of 8
The pieces were combined to form an octagonal cylinder, which was set in the heating coil of a high-frequency furnace. In the octagonal tube, pig iron FC
20 columnar corroded food having a diameter of 80 mm and a height of 100 mm was inserted, and blast furnace slag ground to 6 mm or less was FC
An amount corresponding to 10% by weight was added to 20.
Then melt the FC20 and slag by high frequency,
The specimen was eroded by keeping it at 1600 ° C. for 2 hours. Then, the high frequency was stopped, the melt was discharged, the octagonal specimen was taken out, and melted by cast iron and slag. The thickness of the test piece was measured to examine the corrosion resistance. The results are shown in Table 5.

From these results, the examples according to the present invention are far superior in corrosion resistance to the conventional type comparative example 3.

EFFECTS OF THE INVENTION The present invention may improve the corrosion resistance of conventional dry materials and provide an effective means for improving the durability.
More importantly, it is required to have corrosion resistance, spall resistance, and high hot strength of tapholes of blast furnaces and tundish furnaces used in the ingot making process of steel, which were difficult to apply with conventional dry materials. It is possible to expand the use for various purposes.

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Claims (2)

[Claims] 1. A compound or compounds selected from the group consisting of (a) an alkali metal salt or ammonium salt of orthophosphoric acid, and an alkali metal salt or ammonium salt of condensed phosphoric acid, and (b) dihydrogen tripolyphosphate. A powder binder composition composed of aluminum and used for bonding a powdery amorphous refractory material in a substantially anhydrous state. 2. Aluminum dihydrogen tripolyphosphate is 70
% Or less, The powder binder composition according to claim 1.