JPS62111B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a monolithic refractory material for hot construction of molten metal containers or molten metal processing equipment.
To explain in more detail, it has excellent workability and durability in irregularly shaped materials that are constructed in hot conditions, such as hot sprayed materials for converters and refining pots, hot poured materials, and press-fitted materials for degassing equipment. It was developed with the aim of providing a material that can Conventionally, the construction method of these monolithic refractory materials for hot construction was determined by the construction equipment and the construction site, and the material was selected based on the construction method, but each had restrictions on construction conditions and their durability was also not satisfied. It wasn't something. In other words, in the case of sprayed materials for converters, the physical properties of the constructed material are low, and not only is its durability unsatisfactory, but also the continuous casting ratio has increased in recent years, forcing construction at high temperatures. A decrease in the adhesion rate during construction and furthermore, peeling of the constructed body is becoming more common. In addition, hot pouring materials, which have recently been increasingly used for repairing converter charging walls or tapping walls, can be used at high temperatures of 1000°C or higher to produce good boiling. The result is a constructed body with relatively excellent physical properties and exhibits better durability compared to sprayed materials. However, when the construction temperature drops below 1000°C, conventional hot-poured materials have a major drawback: they do not have the strength to be used as a construction body, and cannot be used as repair materials. Furthermore, damage to the bottom of the furnace has become a major problem in top/bottom blowing, which has become the mainstream operation of converters these days. The use of hot pouring materials is being considered for repairing the hearth bottom, but conventional hot pouring materials have the disadvantage of low fluidity in hot conditions, so they cannot be used for hearth bottom repair. In other words, the method of constructing hot-poured material for the purpose of repairing the hearth bottom is to pour hot-poured material in the form of a slurry mixed with 15 to 25% moisture into a tilted converter using a scrap shoot, etc. However, conventional hot pouring materials do not take fluidity in hot conditions into consideration, so when the furnace is placed upright, A major drawback is that the materials used do not flow satisfactorily into the areas that require repair, making it impossible to carry out sufficient work. On the other hand, press-fit materials for repairing degassing equipment are
Currently, alumina-based products are often used, but these have been developed with the assumption that they will be applied after the temperature of the degasser has decreased, so their physical properties deteriorate as the application temperature increases. The current situation is that corrosion resistance has decreased significantly. However, taking a long cooling period like this is not only disadvantageous for the operation of the degassing equipment, but also requires drying and heating processes after construction, which is also a problem from an energy-saving perspective. It is also unfavorable from the perspective of the effect it has on the bricks being kiln. Furthermore, when installing on the inner cylindrical surface of a immersion pipe or the bottom of a tank in an RH degassing device, there is no problem even if the adhesive strength with the base material is not very strong, but structurally speaking, it is difficult to apply the adhesive strength to the base material alone. When it is necessary to hold the applied material, conventional press-fit materials have low adhesive strength and cannot hold the applied material with adhesive strength alone. Recently, it has been considered to set a metal frame on the trunnion of a converter or on the slag line of a molten steel ladle, and press-fit or pour monolithic refractory material therein. It is thought that the constructed body obtained by this method will have better physical properties and be more durable than the currently used sprayed materials, but conventional press-fit or hot-poured materials do not have sufficient adhesion to the base material. Therefore, it could not be used for this purpose. Hitherto, proposals have been made for hot boiling hardening methods (Japanese Unexamined Patent Application Publication No. 1983-1999).
No. 95082), the purpose could not be fully achieved, especially when the temperature at the construction site was below 1000℃. The present invention was made in consideration of the above-mentioned circumstances, and was made as a result of intensive research into the adhesiveness and fluidity of monolithic refractory materials for hot construction. The present invention provides a material with excellent workability and durability in monolithic refractory materials that are constructed under constant heat. In other words, by adding phosphoric acid, phosphates, lactams, etc., and, depending on the construction method, a hardening agent, to a refractory material whose particle size is configured according to the construction method, a monolithic refractory material for hot construction can be obtained. It was discovered that this material exhibits excellent workability and durability, leading to the present invention. Regarding phosphoric acid or phosphates as a binder for amorphous refractory materials, the use of various phosphoric acids or phosphates has been reported so far, and the use of thermosetting resins, lactones, lactams, and heterocyclic Monolithic refractories using binders in combination with compounds, oxycarboxylic acids, etc. have also been proposed (Japanese Patent Application Laid-open Nos. 58-20771, 58-69782, 59-
Nos. 137369 and 59-137370), but these are intended for curing at room temperature, and there are difficulties in using them as hot pouring agents. The present invention is characterized in that by using phosphoric acid or phosphates in combination with lactams, etc., in addition to acting as a mere binder, the material maintains sufficient slurry viscosity in a low moisture range. Although the details of the mechanism of action when lactams are used in monolithic refractory materials for hot construction are not clear, it is presumed that the following actions occur when used in combination with phosphoric acid or phosphates. be done.
Lactams etc. in a heated aqueous solution ring-open and react with the phosphoric acid or phosphates used in combination, producing a chelate compound, imparting reactivity at low temperatures to the phosphoric acid or phosphates, and further A special aggregation phenomenon is expressed in the refractory material-water dispersion system, and hot fluidity and boiling phenomenon are maintained even in the low moisture range. In other words, the material is in a special agglomerated state due to ring-opening of lactams etc. in an aqueous solution and chelate compounds generated from phosphoric acid or phosphates, and can be used as a slurry as a monolithic refractory material for hot construction up to low moisture areas. It is thought to maintain viscosity and exhibit the following effects. (1) In general, the better the wettability of hot-sprayed materials with the base material, the better the adhesive strength. Therefore,
It is said that as the construction temperature increases, the adhesion to the base material deteriorates and the amount of water required for construction increases. By using lactams, etc., the spray material of the present invention maintains the slurry state necessary for adhesion of the spray material even in the low moisture range, as mentioned above, and has stable adhesive properties even at high temperatures. Furthermore, the resulting constructed body has excellent physical properties and is therefore highly durable. Also,
When the material of the present invention is used in a relatively low temperature range where conventional spraying materials have good adhesion, it is possible to perform construction with lower moisture than when using conventional materials, and as a result, , a constructed body exhibiting better physical properties is obtained, and its durability is further improved. (2) For hot-poured materials, the combination of lactams, etc., and phosphoric acid or phosphates can maintain a slurry state even in low-moisture regions, making it possible to maintain the slurry state even in low-moisture regions. The boiling phenomenon is maintained for a long time and exhibits excellent fluidity under hot conditions, resulting in a construction body with low porosity and strong adhesive strength. Furthermore, in conventional hot-poured materials, phosphoric acid or phosphates do not exhibit sufficient binder effect at temperatures below 1000°C, making it impossible to obtain the strength required for construction. Phosphoric acid or phosphate salts are highly reactive, and even when applied at temperatures below 1000°C, they function well as a binder and form a strong construction. Of course, the material of the present invention
When applied at temperatures above 1000℃, it exhibits better adhesion and durability than conventional hot-poured materials, and can be used over a wide temperature range. (3) Press-in materials are not intended for conventional low-temperature construction, but are instead carried out in hot conditions and apply the boiling phenomenon to filling, and their effects are similar to those of hot-poured materials. It is. As the refractory materials used in the present invention that have excellent workability as described above, there are various known refractory materials such as alumina, lorite, dolomite, maguro, and magnesia. It is preferable to use basic refractory materials such as magnesia clinker and dolomite clinker, which have high fire resistance and excellent corrosion resistance, or a combination of basic materials and neutral materials such as alumina. Phosphoric acids or phosphates that can be used in the present invention include various phosphoric acids, phosphates, and condensed phosphates, and one or more of these can be selected and used. and there is no need to specifically limit it. However, when selecting and using only one type, or when combining two or more types, condensed phosphoric acids such as tripolyphosphoric acid, hexametaphosphoric acid, tetrapolyphosphoric acid, or alkali metal salts of these phosphoric acids are used as one type. It is preferable to use The amount used is 0.5 to 10 parts by weight, preferably 1.5 to 8 parts by weight, per 100 parts by weight of the refractory material.
Parts by weight. If the amount of phosphoric acid used is less than 0.5 parts by weight, the resulting constructed body will not exhibit sufficient strength. Moreover, if the amount is more than 10 parts by weight, the refractoriness of the construction object will decrease, and not only will the corrosion resistance as a refractory be inferior, but it is also unfavorable from the viewpoint of the quality of the steel. Next, the lactams referred to in the present invention are as they are,
Alternatively, it can open the ring to form a chelate with phosphoric acid or phosphates, and is a tautomer with lactams and lactams such as β-propiolactam, γ-butyrolactam, δ-valerolactam, and ε-caprolactam. lactims, β-propiolactone, γ-butyrolactone, lactones such as tetronic acid, acid anhydrides such as phthalic anhydride and maleic anhydride, imides such as succinimide and phthalic acid imide, and dioxane. lactides,
Heterocyclic compounds such as cyclic clades can be used,
One or more of these may be selected and used. The amount used is per 100 parts by weight of refractory material.
The amount is 0.2 to 6 parts by weight, preferably 0.5 to 4 parts by weight. If the amount of lactams, etc. used is less than 0.2 parts by weight, the slurry retention ability of the refractory material-water dispersion system will decrease, resulting in a construction product with poor physical properties and adhesive properties, which is not preferable. Furthermore, since lactams and the like are organic substances, they disappear after construction and create pores, so it is not preferable to add more than 6 parts by weight. Further, the ratio of lactams and the like to phosphoric acid or phosphates is preferably 0.05 to 2 parts by weight of lactams, etc. to 1 part of phosphoric acid or phosphates. When using the monolithic refractory material for hot construction according to the present invention as a spraying material, it is necessary to have suitable hardening properties, and for that purpose, sodium silicate, potassium silicate, slaked lime, etc. Known curing agents such as , calcium aluminate, and magnesium hydroxide can be used in combination. The amount used is determined by the rate of curing reaction with phosphoric acid or phosphate, but is 0.5 to 100 parts by weight of the refractory material.
5 parts by weight is preferred. The amount of this hardening agent added is 0.5
If it is less than 5 parts by weight, the curing speed will be slow and the curing properties as a spray material will not be exhibited, and if it is more than 5 parts by weight, curing will be too fast and curing may occur at the nozzle hole. As a construction method using the material of the present invention, known methods such as spraying, press-fitting, pouring, and vibration casting can be applied. The material of the present invention can be used instead of the material. In other words, in the spraying method, 20 to 50% by weight of particles with a particle size of 1 to 3 mm, 0.125
~1mm 20~40% by weight, 0.125mm or less 30~45% by weight, and in the press-in method, particles with a particle size of 1~3mm are 10~30%.
Weight %, 0.125-1 mm 30-50 weight %, 0.125 mm or less 35-60 weight % is preferable, and in the pouring method or vibration casting method, particles with a particle size of 1-10 mm 40-60 weight %, 0.125-1 mm 15 ~35% by weight, 0.125mm or less
A particle size range of 25-45% by weight is desirable. As described above, the present invention uses a combination of lactams and phosphoric acids, etc. to achieve stable adhesion over a wide temperature range from relatively low to high temperatures, and provides high durability due to excellent physical properties for spraying and press-fitting. ,
The present invention provides an amorphous material for hot construction that can be applied to various construction methods such as pouring. Examples will be shown below to specifically explain the details of the monolithic refractory material for hot construction according to the present invention. Examples 1 to 6 Internal volume lined with dolomite bricks for converter
A gas furnace of 1100 x 1100 x 1300 (H) mm was heated to 1300°C, and magnesia clinker and dolomite clinker having the compositions shown in Table 1 were heated as shown in Table 2.

[Table] Table 2 shows the measurement results of the adhesion rate and physical properties of the constructed bodies obtained by spraying the spraying material with the following composition.

[Table] Comparative Examples 1 to 3 Table 2 also shows the results of spray materials having the formulations shown in Table 2, which were made in the same manner as in Examples 1 to 6 except that lactams and the like were not used. As is clear from the results in Table 2, the sprayed material using the material of the present invention shows a very high adhesion rate compared to the conventional sprayed material (comparative example) even at a high construction temperature of 1300°C. In addition, the physical properties showed low porosity and high compressive strength, indicating that when the material of the present invention is used as a spray material, an excellent construction product can be obtained. Example 7, Comparative Example 4 Actual furnace tests of sprayed materials using the materials of the present invention were conducted using the materials of Examples 3 to 5 in a 90-ton converter at Steel Works A with an average tapping temperature of 1685°C. The furnace wall temperature during spraying is
The temperature was 1300-1350℃. The results are shown in Table 3.

[Table] As seen in Example 7, the hot sprayed material using the material of the present invention has excellent properties that cannot be obtained with conventional sprayed materials, even in a furnace operating at a high temperature with an average tapping temperature of 1685°C. It exhibited good adhesion and was 2.5 times more durable than conventional sprayed materials. Examples 8 to 12, Comparative Examples 5 to 6 Magnesia clinker with particle size of 1 to 5 mm 50
Weight%, 20% by weight of 0.125-1mm and 0.125mm
30% by weight of the following phosphates shown in Table 4,
After adding water to a hot pouring material made of the material of the present invention to which lactams etc. have been added to form a slurry,
It was poured into a mold using Maguro bricks on the bottom set in an electric furnace maintained at 600°C and boiled and hardened. After cooling, the adhesive strength of this construction body to the bottom surface of maguro bricks was measured by a shearing method. Furthermore, the physical properties of the obtained construction body were also measured. As a comparative example, a test was conducted in the same manner as in the example except that lactams and the like were not used. The results are summarized in Table 4.

【table】

[Table] Example 13, Comparative Example 7 An actual furnace test using the materials of the present invention shown in Table 4 as hot-cast materials was carried out in a 90t converter at A steelworks with an average tapping temperature of 1685°C. Furnace wall temperature at the start of construction is approximately 1350℃, and approximately 1100℃ at the end of construction.
It was hot. The results are shown in Table 5.

[Table] Examples 14 to 15, Comparative Examples 8 to 9 In order to confirm the hot fluidity of the hot poured material of the present invention, it was used as a bottom repair material in a 90t converter at A Steel Works. Phosphates and lactams shown in Table 6 (comparative examples do not add lactams, etc.) to 50% by weight of magnesia clinker with a particle size of 1 to 5 mm, 20% by weight of 0.125 to 1 mm, and 30% by weight of 0.125 mm or less. In addition, hot pouring material made into a slurry with water was poured into a tilted converter using a scrap chute, then the furnace was stood upright and poured into the desired bottom of the furnace. The results are shown in Table 6.

[Table] The amount of fluid flowing was determined visually relative to the amount of construction.
The hot-casting material using the material of the present invention, which is characterized by the addition of lactams, etc., has the following characteristics compared to conventional hot-casting materials that do not contain lactams:
As shown in Table 4, it was found that sufficient installation strength and durability can be obtained even when the construction is performed at a low temperature of 1000℃ or less, and the durability in an actual furnace at a high temperature of 1000℃ or higher is shown in Table 5. As a result, the durability is more than three times that of conventional products. Furthermore, the material of the present invention has good fluidity when used as a pouring material, so as seen in Examples 14 and 15, almost all of the applied amount flowed to the concave part of the furnace bottom and then boiled and hardened. Corrosion resistance was also significantly superior. On the other hand, conventional hot poured materials have poor fluidity, so that only 50 to 60% of the applied amount flows to the bottom of the furnace, and grain separation occurs, resulting in a short service life. Examples 16 to 17 Table 7 shows the results of using the monolithic refractory material for hot construction according to the present invention as a press-fitting material as a repair material for the inner cylindrical portion of the immersion pipe of an RH degassing device.

[Table] The refractory materials used were magnesia clinker with a particle size of 1 to 3 mm, 0% by weight, 0.125 to 1mm, 20% by weight,
0.125mm or less 50% by weight. The average processing temperature of the RH degasser is 1640℃, and the processing time per channel is approximately
The duration is 45 minutes. Conventionally, alumina press-in material was used to repair this RH degassing equipment, and it was constructed at a temperature of 200 to 300°C and had a durability of about 40 channels, but due to changes in operating conditions, the construction temperature The temperature was 800 to 1000℃, and the service life was significantly reduced to about 23 channels, but by using the refractory material of the present invention, the service life is now 36 to 39 channels, which is 1.5 to 2 times longer. It became.

Claims (1)

[Claims] 1 0.5 to 10 parts by weight of phosphoric acid or phosphates, 0.2 to 6 parts by weight of lactams, etc. per 100 parts by weight of refractory raw materials
A monolithic refractory material for hot construction characterized by adding a weight part.