CN100529628C - Method for constructing monolithic refractory material and monolithic refractory material used for the method - Google Patents

Abstract

The present invention provides a method for applying an unshaped refractory to a molten metal vessel, a molten metal processing apparatus or a high-temperature furnace, which is superior in workability, service life of an applied body, etc., to conventional thermal spraying methods, and an unshaped refractory used for the method. An amorphous refractory material containing a refractory aggregate and a dispersing agent, which is previously kneaded with addition of construction water and stored in a charging hopper, is discharged from below the charging hopper while adding a coagulant, and is then centrifugally projected, wherein the refractory aggregate is composed of volatile silica and/or calcined alumina. Since the monolithic refractory is fed out from below the charging hopper, it is sufficient that the monolithic refractory is rendered slightly fluid, and the moisture required for the construction can be greatly reduced. In addition, the projection at a certain angle width can easily perform the partial construction.

Description

Construction method of monolithic refractory and monolithic refractory used in the method

technical field

The present invention relates to a method for constructing a monolithic refractory to a molten metal container, a molten metal processing device or a high-temperature furnace, and the monolithic refractory used in the method.

technical background

Conventionally, thermal spraying with a monolithic refractory has been performed as a furnace lining such as a molten metal container, a molten metal processing apparatus, or a high-temperature furnace, or a repair method thereof. This method is shown in the explanatory diagram shown in Figure 6. The monolithic refractories pre-mixed with added construction water are transferred to the nozzle 36 by the pressurized delivery pump 34 through the pressurized delivery pipe 35, and the coagulation accelerator in the coagulant tank 37 is transferred to the nozzle 36. The agent is added into the nozzle 36 with the compressed air of the air compressor 38 for spraying. This construction method is disclosed in, for example, JP-A-10-182246 and JP-A-10-95678.

This method of spraying pre-kneaded monolithic refractories has the effects of less dust generation, labor-saving construction, and a dense construction body compared to the dry spraying method of adding construction water in the nozzle.

However, in this spraying process, since the monolithic refractory is transferred from the hopper to the nozzle through a pressurized delivery pipe, the monolithic refractory has a large amount of moisture in order to obtain stable pressurized delivery. In addition, the structural structure of the monolithic refractory becomes porous, and the strength and corrosion resistance decrease.

In addition, in this thermal spraying process, since the monolithic refractory is blown away with high-pressure compressed air, there is much rebound loss. While preventing dusting is better than dry spray methods, it is not good enough. In addition, in order to inject high-pressure compressed air into the construction, air is involved in the construction body, which has a disadvantage of affecting the compactness.

In this thermal spraying construction, in order to improve construction efficiency, it is considered to increase the pressurized conveying speed of the monolithic refractory. However, the pipe resistance in the pressurized delivery pipe becomes larger in proportion to the pressurized delivery speed. In order to counteract this pipeline resistance, it is necessary to reinforce the pressurized delivery pipe, increase the capacity of the pressurized delivery pump, or increase the inner diameter of the pressurized delivery pipe. In each case, the overall size of the device is increased, which is not preferable.

In addition, it is known to add refractory ultrafine powder to a monolithic refractory in thermal spraying. These refractory ultrafine powders impart fluidity during construction to monolithic refractories. Fluidity can reduce the amount of construction water added to achieve the effect of reducing water to make the construction compact, improve the necessary thermal strength of the refractory construction structure and the corrosion resistance to molten metal, etc. In addition, it also contributes to the adhesion and adhesiveness necessary for spraying.

Volatile silica or calcined alumina is known as the refractory ultrafine powder used. Volatile silica or calcined alumina is easy to obtain as ultrafine powder, and exerts excellent water reducing effect. However, volatile silica or calcined alumina is a chemically active substance, which is easy to react with the coagulant, so the coagulant added during the spraying construction makes the refractory ultrafine powder aggregate, and the viscosity of the monolithic refractory is due to the addition of the coagulant. Surge in the nozzle section. It also causes pulsation or intermittent phenomena when spraying from the nozzle, resulting in a decrease in construction efficiency and poor construction.

In this thermal spraying process, it is known that adding refractory coarse particles with a particle diameter of more than 10 mm or wires with a length of about 5 to 50 mm to the monolithic refractory has the effect of imparting strength against heat and preventing cracking. Nevertheless, the addition of a coagulant increases the viscosity of the monolithic refractory, and the phenomenon of bleeding occurs between the added refractory coarse particles, between the metal wires, or the refractory coarse particles and the metal wires are close to each other, and nozzle clogging is prone to occur. Disadvantages of significantly reduced constructability. Furthermore, when the monolithic refractory material containing refractory fine powder is combined with refractory coarse particles or wires to improve fluidity, the viscosity increase after adding a coagulant is particularly significant, and it is substantially difficult to carry out spraying construction.

As a construction method for monolithic refractories, a centrifugal projection method with a horizontally rotating impeller was proposed in Japanese Patent Publication No. 50-39403. However, compared with the above-mentioned spraying construction, the construction body adhesion and durability of this method are inferior. The corrosion gap is too large to be popularized.

Contents of the invention

The invention provides a construction method for a monolithic refractory, which is a construction method for lining or repairing a molten metal container, a molten metal processing device or a high-temperature furnace, and is characterized in that a mixed refractory is added to the monolithic refractory in advance. Refining construction water, stored in the loading hopper, adding coagulant while moving to the bottom of the loading hopper, and using the horizontally rotating impeller installed at the lower end of the loading hopper for centrifugal projection, the amorphous refractory mixed with refractory super Made of finely powdered refractory aggregates.

In the construction method of the above-mentioned monolithic refractory, the centrifugal projection is carried out with a certain angle range in the circumferential direction.

In the construction method of the above-mentioned monolithic refractory, the refractory ultrafine powder is volatile silica and/or calcined alumina.

In the construction method of the above-mentioned monolithic refractory, the monolithic refractory is further mixed with a dispersant.

In the construction method of the above-mentioned monolithic refractory, in the monolithic refractory, 50% by mass or less of refractory coarse particles are further blended with respect to 100% by mass of the refractory aggregate.

In the construction method of the above-mentioned monolithic refractory, in the monolithic refractory, 10% by mass or less of metal wire is further blended with respect to 100% by mass of the refractory aggregate.

In the construction method of the monolithic refractory described above, 3 to 10% by mass of construction moisture is added and kneaded to the monolithic refractory, and the slump value is 20 cm or less according to the measurement method based on the standard of JIS A1101.

An object of the present invention is to provide a construction method and a monolithic refractory used in the method which are better in workability and service life of the monolithic refractory than the conventional spraying method.

The present invention is a method for constructing monolithic refractories on molten metal containers, molten metal processing devices or high-temperature furnaces, and is characterized in that the monolithic refractories stored in the charging hopper which is pre-added with construction water and kneaded are added to accelerate coagulation. The agent is moved out of the bottom of the loading hopper, and then centrifugally projected.

In the construction method of the present invention, since the monolithic refractory is supplied to the discharge part by transferring it from the bottom of the charging hopper, there is no long and narrow inner diameter pressurized delivery pipe used in the conventional spraying method. , there is no problem of pipeline resistance. As a result, it is enough to impart some fluidity to the monolithic refractory, so the water used for construction can be greatly reduced. In addition, since compressed air is not required due to centrifugal projection, it can be made denser without entraining air in the construction body.

The centrifugal projections of the present invention can be performed with angular amplitudes in the circumferential direction. Projecting at an angle can facilitate localized construction. In addition, for example, when the inner diameter of the molten metal container to be constructed is extremely large, the projection distance becomes longer, which reduces the adhesion of the monolithic refractory and makes accurate projection to the part to be constructed difficult. However, placing the construction equipment close to the container Walls, projecting at an angle eliminates this problem.

The carrier of the coagulant can also use air. However, the pressure and flow rate of the air in this case are small compared with the high-pressure compressed air necessary for spraying a monolithic refractory to blow off from the nozzle in the conventional spraying method. Therefore, there is no problem of air being caught in the construction body.

In the present invention, when the applicable monolithic refractory is a refractory ultrafine powder containing volatile silica or calcined alumina, the viscosity of the monolithic refractory increases particularly significantly by adding a coagulant. Nevertheless, the present invention uses centrifugal projection to carry out construction, because the supply to the spraying part of the monolithic refractory is sent from the bottom of the charging hopper, so there will be no clogging of the nozzle or the occurrence of pipe resistance in the past spraying method. Pulsation or intermittent phenomenon during spraying, excellent workability. As a result, in the present invention, when a monolithic refractory material containing volatile silica or calcined alumina as a refractory ultrafine powder is used, the water-reducing effect of volatile silica or calcined alumina improves construction. The strength and corrosion resistance of the body can give full play to the effect of adhesion and adhesiveness endowed by chemical activity.

In the present invention, since there are no nozzles and pressurized delivery pipes, even if a monolithic refractory material added with refractory coarse particles or wires is used, the problems of nozzle clogging and pipeline resistance that occurred in the conventional spraying method are eliminated. Therefore, even when using a monolithic refractory material containing refractory coarse particles or wire and refractory fine powder, construction can be carried out without any problem when the refractory fine powder reacts with the coagulant to significantly increase the viscosity. , Adding refractory coarse particles or metal wires can prevent cracking of the construction body and impart strength.

In addition, when refractory ultrafine powders such as volatile silica and calcined alumina are contained, their own specific gravity may be small, and they are easily separated from other aggregates after being discharged from the spray nozzle during spray coating construction. resulting in uneven construction. Because the shapes of refractory coarse particles and metal wires are different from other aggregates, they are easy to segregate from the refractory structure. In contrast, the centrifugal projection of the present invention prevents the separation and segregation of ultrafine powder, refractory coarse particles or wires during construction in order not to be blown away by high-pressure compressed air during spraying construction, and further improves the quality of monolithic refractories. Excellent adhesion, make the structure of the obtained construction body uniform, improve corrosion resistance and peeling resistance.

Next, a monolithic refractory material that is suitable for carrying out the construction method of the present invention will be described.

The refractory aggregate of the monolithic refractory used in the present invention is sintered alumina, fused alumina, alumina, aluminum shale, mullite, silica, cooked refractory clay, andalusite (andulusite), talc (agalmatolite) , silicon carbide, fused silica, magnesia, magnesia-calcium oxide, Al ₂ O ₃ -MgO-based spinel, chromite, sillimanite, and the like. In addition, they can be arbitrarily combined with one selected from zirconia, carbon, clay, light-burned magnesia, pitch, mesophase pitch, infusible pitch, silicon nitride, aluminum nitride, boron carbide, zirconium boride, chromium oxide, etc. more than one species.

In the monolithic refractory used in the present invention, refractory ultrafine powder is used as part of the refractory aggregate. The preferred particle size of the refractory ultrafine powder is 10 μm or less on average as measured by a particle size distribution measuring device using a laser diffraction method.

As the refractory ultrafine powder, volatile silica and/or calcined alumina that impart adhesion, adhesiveness, strength and corrosion resistance to monolithic refractories are preferred,

Volatile silicon oxide, also known as quartz powder, silica fume, or microsilica, is an amorphous silicon oxide superfine powder formed by oxidation of SiO gas in air when silicon, ferrosilicon, or zirconia is produced. It is a spherical particle with an average of about 0.2-0.5 μm, and the actual use form is a secondary particle aggregated with submicron particles. Its quality is preferably SiO ₂ purity of 90% by mass or higher, and specific surface area of about 5 to 40 m ² /g.

Calcined alumina is a substance formed by burning aluminum hydroxide produced by the Bayer process. The combustion temperature is generally around 1000-1300°C. Because the combustion temperature of the refractory raw material is treated at a relatively low temperature, it is also called light-burned alumina. The main component is α-Al ₂ O ₃ , and the purity of Al ₂ O ₃ is more than 99% by mass. It is preferable to use ultrafine powder with an average particle diameter of 10 μm or less. It is different from sintered alumina which is obtained by burning calcined alumina as a raw material at a high temperature of 1600°C or higher.

The proportion of the refractory superfine powder in the refractory aggregate is preferably 1-30% by mass, more preferably 3-25% by mass. If less, the water-reducing effect cannot be fully exerted. Excessive sintering tends to lead to cracking due to sintering shrinkage and decrease in corrosion resistance.

Dispersants can also be called desolidizers according to their functions. Gives fluidity to monolithic refractories and maintains water-reducing effect. The specific type of dispersant does not have any specific substances, such as sodium tripolyphosphate, sodium hexametaphosphate, sodium superpolyphosphate, acidic sodium hexametaphosphate, sodium borate, sodium carbonate, polymetaphosphate and other inorganic salts, sodium citrate, Sodium tartrate, sodium polyacrylate, sodium sulfonate, polycarboxylate, carboxyl group-containing polyethers, β-naphthalenesulfonates, naphthalenesulfonic acid, etc. The preferable addition amount is the range of 0.005-1 mass % with respect to 100 mass % of refractory aggregates.

As the binder, for example, alumina cement, magnesia cement, sodium phosphate, sodium silicate and the like can be used. Its addition ratio is 100 mass % with respect to refractory aggregate, and it is preferable to adjust it to the range of 1-15 mass % according to the kind of binder. The binder is not necessarily required when a sufficient coagulation effect can be obtained by the type and amount of the coagulant, refractory ultrafine powder, and the like.

Adding refractory coarse particles or metal wires to the monolithic refractory can effectively prevent cracking and improve strength and corrosion resistance. The maximum particle size of the refractory aggregate in the monolithic refractory is usually 3 to 8 mm, and the refractory coarse particles are larger than the particle size of the refractory aggregate, for example, 10 to 50 mm. As the material of the refractory coarse particles, fused alumina, calcined alumina, fused spinel, calcined spinel, silicon carbide, or refractory waste materials based on them can be used. The addition amount is 50 mass % or less with respect to 100 mass % of refractory aggregates, Preferably it is 1-40 mass %. Too much will result in reduced adhesion.

In addition, the material of the wire added to the monolithic refractory is steel, iron, stainless steel, or the like. Among them, stainless steel excellent in heat resistance is preferable. Considering both the diameter and the length, it is preferable, for example, to have a diameter of 0.1 to 2 mm and a length of 5 to 50 mm. The cross-sectional shape may be a circle, a polygon, or the like. The amount added is 10% by mass or less, more preferably 0.1 to 7% by mass, based on 100% by mass of the refractory aggregate. Too much leads to lower corrosion resistance.

As additives other than the above added to the monolithic refractory of the present invention, organic fiber, ceramic fiber, tackifier, clay, CMC, bentonite, metal powder, lightweight material, curing accelerator, curing retarder, etc. , aluminum lactate, aluminum glycolate lactate, aluminum glycolate, silica sol, alumina sol, etc. are used alone or in combination.

The monolithic refractory used in the present invention is kneaded by adding water in advance by kneading or the like at the time of construction. In this kneading of the monolithic refractory, the water content of the construction is 3 to 10% by mass relative to the appearance of the monolithic refractory in the dry powder state, and it is used in accordance with JIS A1101 (Japanese Industrial Standard: Slump Test Method for Concrete) as For the slump value measured by the standard method, it is preferable to adjust the softness to 20 cm or less, for example. If the water content of the monolithic refractory after kneading is less than the above, the fluidity and plasticity will decrease, and it will not be able to be smoothly transferred to the bottom of the charging hopper. The amount of water in the construction is too much, and the strength and corrosion resistance of the monolithic refractory after construction are insufficient. Unshaped refractories with a slump value exceeding 20cm are easy to flow out of the hopper automatically, and it is not easy to adjust the delivery amount. In addition, the adhesion and filling properties of the monolithic refractory also tend to decrease. A more preferable slump value is 5 to 15 cm.

As the coagulant, either liquid or powder can be used. From the viewpoint of adhesion and bonding strength of the monolithic refractory, its addition ratio is preferably 0.2 to 5% by mass in terms of solid content relative to 100% by mass of the refractory aggregate of the monolithic refractory. Examples of liquid coagulants include aqueous solutions of sodium aluminate, potassium aluminate, sodium silicate, potassium silicate, and sodium phosphate. These liquid coagulants may be combined with coagulants such as anionic or cationic coagulants as needed. Examples of powdery coagulants include sodium aluminate, potassium aluminate, sodium silicate, sodium phosphate, sodium carbonate, calcium chloride, calcium hydroxide, calcium oxide, calcium aluminate, magnesium hydroxide, Portland Cement, aluminum sulfate soil, etc.

These coagulants can be added in a state of being mixed with refractory fine powder. For example, refractory fine powders such as alumina may be mixed in a range of, for example, 50% by mass or less in terms of solid content as a coagulant.

A brief description of the drawings

Fig. 1 is an explanatory diagram of the construction method of the present invention.

Fig. 2 is an enlarged longitudinal sectional view of an example of construction equipment used in the present invention.

Figure 3 Figure 2 A-A line sectional view.

Fig. 4 is an enlarged longitudinal sectional view of another construction device used in the present invention.

Fig. 5 is a B-B line sectional view of a part of the impeller in Fig. 4 .

Fig. 6 is an explanatory diagram of a conventional thermal spraying construction method.

Detailed ways

Hereinafter, as a suitable embodiment of the present invention, repairing a molten steel pot will be described as an example.

In Fig. 1 and Fig. 2, the construction device 1 is equipped with a hopper 3 (hopper) for storing the pre-mixed monolithic refractory 2, a screw feeder 4 for cutting the monolithic refractory 2 in the hopper 3, and a A coagulant supply device 7 for adding coagulant to the monolithic refractory 2, a stirring rod 11a for agitating the coagulant and the monolithic refractory, and a horizontally rotating impeller 6 for centrifugally projecting the monomorphic refractory 2 in the horizontal direction. On the top plate of the charging hopper 3 is provided an opening and closing plate 19 as an inlet for the monolithic refractory 2 . The charging hopper 3 has a down-spinning pull pin, and the pin pulling part has a vibration motor 8, and the vibration motor 8 can promote the delivery of the monolithic refractory in the charging hopper 3.

The screw feeder 4 has its axis concentric with the drop tube 5, and the upper end of its shaft is supported by a bearing on the top of the hopper 3, and is driven by a drive motor 9 on the top. The screw feeder 4 also has the function of preventing the monolithic refractory 2 from flowing down from the charging hopper 3 when the construction is suspended.

And, there is a drop tube 5 at the lower end, and an impeller 6 is installed at the lower end of the drop tube 5 of the loading hopper 3 . The impeller 6 is driven and rotated by a drive motor 21 mounted on a base 20 fixed to the drop cylinder 5 . A cylinder shaft 22 is provided on the outer periphery of the drop cylinder 5, and the impeller 6 can be rotated through a bearing 23.

The impeller 6 has an upper plate 24 , a lower plate 25 facing thereto, and radial feathers 26 connected between the upper plate 24 and the lower plate 25 as shown in FIG. 3 . The swivel strut 30 is fixed on the lower plate 25 . The monolithic refractory 2 is radially projected around the rotating shaft 10 by the centrifugal force applied by the feathers 26 of the impeller 6 . The number of feathers 26 is preferably, for example, about 3 to 10 in the circumferential direction. Take 8 as an example here.

The driving motor 21 which rotates the impeller 6 is designed as one here, and both sides can be provided in order to keep the weight balance between the left and the right. The output shaft of the driving motor 21 is fixed with a driving rotating body such as a pulley 27 (pull), and is connected with the cylinder shaft 22 by a V-belt 28 .

The drive motor 21 is preferably an inverter type, and is preferably capable of reverse rotation. In addition, these impeller rotation drives are preferably reinforced by frames 29 , 43 .

The rotary support 30 fixed on the impeller 6 has a plurality of plate-shaped or rod-shaped stirring rods 11 a at appropriate intervals above and below. As a result, the stirring rod 11 a is driven to rotate as the impeller 6 rotates. These rotating rods 11a are more useful for stirring the coagulant and the monolithic refractory, so they are preferably located in the drop cylinder 5 . The rotating shaft 10 of the screw feeder 4 is extended further below instead of the said rotating support|pillar 30, and the stirring rod 11a rotated by the rotational drive of this rotating shaft 10 may be provided.

When the screw feeder 4 is sufficient for stirring the coagulant and the monolithic refractory, the stirring rod 11 a is not necessarily required. Furthermore, it is preferable to provide the stirring rod 11b on the rotating shaft 10 in the hopper to prevent filling and solidification of the monolithic refractory in the hopper. The screw feeder 4 is rotationally driven by a drive motor 9 mounted on the hopper 3 .

The fine holes 12 formed in the drop cylinder 5 are covered with a jacket 13 , and a supply pipe 14 communicating with the inside of the jacket constitutes a coagulant supply device 7 . The end of the supply pipe 14 is connected to a coagulant pump delivery device (not shown). The coagulant supply device 7 is not limited to the illustrated structure, and it is sufficient to have a function of adding a coagulant to the monolithic refractory in the drop cylinder 5 or its vicinity.

In the projecting construction of the monolithic refractory, first, the construction device 1 containing the pre-kneaded monolithic refractory 2 in the hopper 3 is suspended by a crane into the molten metal container 17 through the suspension cable 16 . Then, while the screw feeder 4 and the stirring rod 11 a are rotationally driven, the coagulation accelerator is supplied to the monolithic refractory in the drop cylinder 5 . In this way, the monolithic refractory 2 is sufficiently mixed by the stirring rod 11 a while being sent out from the drop tube 5 downward while adding the coagulant. Next, the monolithic refractory 2 is introduced into the center of the impeller 6 rotating at high speed, and is centrifugally projected onto the inner wall of the molten metal container by the action of the feather 26 . The construction device 1 moves up, down, left, and right inside the molten metal container, and projects the monolithic refractory 2 onto the entire inner wall or a desired part.

The screw feeder, the addition of the coagulant, and the operation of the impeller can be operated, for example, through the operation panel 15 outside the molten metal vessel. The up and down movement of the construction device 1 is operated in the middle by the suspension cable 16, and does not require heavy equipment such as the electric rewinding pulley 18 and a crane, and can be easily and accurately controlled up and down.

Fig. 4 and Fig. 5 show other examples of construction equipment for carrying out the method of the present invention for projecting monolithic refractories at a constant angle in the circumferential direction. The entire structure of supplying the coagulant and driving the impeller rotation is the same as that of the apparatus shown in Figs. 1 to 3 above, so detailed description thereof will be omitted. The same parts as those shown in FIGS. 1 to 3 are denoted by the same symbols.

In this example, an endless flat belt 39 is wound around the feathers 26 and the outer peripheries of the impeller 6 . When the flat belt 39 is wound on the impeller 6, it is reversed at one end of the impeller 6, and the impeller 6 is provided with an open portion where the flat belt 39 is not wound. The flat belt is guided by a pulley 41 pivoting on a horizontal support table 40 above the impeller 6 . The flat belt 39 is wound around the impeller 6, transmits the driving force of the impeller 6, and rotates synchronously with the impeller 6. Therefore, the rotation of the flat belt 39 is synchronized with the impeller.

The monolithic refractory 2 sent out from the drop tube 5 is dispersed in all directions by the feathers 26 of the impeller 6. In the same construction device, after reaching the outer periphery of the impeller 6 and being prevented from being dispersed by the flat belt 39, it moves on the flat belt 39. . When the monolithic refractory 2 reaches the place where the flat belt 39 is not wound around the outer circumference of the impeller 6, it breaks away from the restraint of the flat belt 39 and is projected to the outside. Projection with a certain angular range is thus possible. The figure shows the projection to the right.

An orientation guide 44 is provided on an open portion of the impeller 6 where the flat belt 39 is not wound. The upper side of the orientation guide body 44 is fixed on the horizontal support table 40 . The projection angle of the monolithic refractory 2 can further be twisted by means of the orientation guide 44 .

Tables 1 to 3 show the construction conditions and test results of the examples of the present invention and their comparative examples. The construction object is a molten metal container with a bottom diameter of 3.0m, an upper end diameter of 3.5m, and a height of 3.0m pasted with refractory materials. A construction body with a thickness of about 80mm is formed using 500kg of unshaped refractory materials.

Embodiments 1 to 13 are constructed using the impeller-type construction device shown in FIGS. 1 to 3 above. After pre-adding construction water and kneading, put the monolithic refractory into the hopper, and add the coagulant while centrifugally projecting. The construction conditions were discharge speed: 6 m ³ /hour, diameter of impeller: 500 mm, and number of rotations: about 800 rpm. In Comparative Example 5, centrifugal projection construction was carried out without adding monolithic refractories and coagulants. Other conditions were carried out in the same manner as in Example 1 above.

In Comparative Examples 1 to 4 and Comparative Example 6, the monolithic refractories shown in the table were sprayed using a spraying apparatus corresponding to that shown in FIG. 6 . The monolithic refractory shown in the table is added with construction water, and after mixing, it is sent to the nozzle by a pressurized delivery pump, and the coagulant is added together with the high-pressure air in the nozzle while spraying. The construction condition is spray speed: 2m ³ /hour.

The composition of the monolithic refractories used in each example, and the average particle diameters of volatile silica and calcined alumina were determined by a laser diffraction method. The particle diameters of other refractory aggregates were measured and determined based on JIS. The slump value is measured in accordance with JIS A1101 for the kneaded product with added water for construction.

Table 1 and Table 2 show the construction of alumina-magnesia monolithic refractories. Projection or spraying is performed on the inner wall surface made of alumina-magnesia monolithic refractory. Table 3 shows the construction of alumina-carbonaceous monolithic refractories. Projection or spraying is applied to the inner wall surface made of alumina-carbon.

The adhesion of the monolithic refractory is calculated by the adhesion rate on the vertical wall. Workability is a measure of the degree of workability primarily due to pipe resistance that affects flow. For example, if the pipeline with high resistance is pulsating or intermittent when spraying, or the nozzle is blocked, the workability will be reduced. Divided into ◎best ○good △slightly bad ×bad 4 stages of evaluation.

The test method for the compactness of the construction body is to cut out a test piece from the construction body and measure the bulk density. The higher the bulk density, the higher the compactness.

Cracking resistance is to cut out the test piece from the construction body, heat it to 1500°C and then air-cool it, repeat it several times, visually observe the degree of cracking, and divide it into 1 to 5 stages for evaluation. The larger the value, the better the cracking resistance .

From the test results of the examples of the present invention shown in Table 1 and Table 3, it can be seen that according to the present invention, excellent workability is achieved even with a small amount of water in construction. In particular, the use of amorphous refractories added with calcined alumina or volatile silica has better adhesion, workability, compactness and corrosion resistance of the structure of the construction body. The monolithic refractory materials shown in Examples 4 to 7 to which refractory coarse particles or wires are added have no problem in workability, and due to the characteristics of refractory coarse particles or wires, the crack resistance of the construction body is further improved. .

On the other hand, in Comparative Examples 1 to 4 and Comparative Example 6 of thermal spraying construction, although the adhesion rate of Comparative Example 1 was relatively high, workability and compactness were not good, and as a result, corrosion resistance deteriorated significantly.

In Comparative Example 3 and Comparative Example 6, a monolithic refractory that does not contain volatile silica or calcined alumina was used, but a large amount of water was added to ensure workability. As a result, the compactness of the construction body is reduced, and the corrosion resistance is greatly reduced.

In Comparative Example 2 and Comparative Example 4 in which refractory coarse particles were added, smooth ejection was not performed, and the workability decreased particularly significantly. Although centrifugal projection construction was performed, the adhesiveness of Comparative Example 5 in which no coagulant was added was significantly reduced.

In addition, in the construction methods of Comparative Example 2, Comparative Example 4, and Comparative Example 5, it was not easy to obtain test pieces, so the compactness, crack resistance, and corrosion resistance tests of the structure of the constructed body were not performed.

The construction according to the present invention can be applied to molten metal containers such as blast furnaces, blast furnace tanks, converters, pots, tundishes, degassing furnaces, mixed milling machines, soaking furnaces, heating furnaces, combustion furnaces, firing furnaces, and melting furnaces , Lining or repair of molten metal processing equipment, high temperature furnace. In addition, such construction is performed on a wall surface in a high temperature state such as heat repair of a furnace wall.

According to the invention, the workability of the monolithic refractory is improved, and the obtained construction body also has excellent characteristics, and the number of construction work and the usage of the monolithic refractory are reduced, and the operating rate of various industrial furnace equipment can be greatly improved.

Claims (6)

1. The construction method of a monolithic refractory is a construction method of lining or repairing a molten metal container, a molten metal processing device or a high-temperature furnace, and is characterized in that the monolithic refractory is added and kneaded in advance. After the construction water is stored in the loading hopper, it is transferred to the bottom of the loading hopper while adding the coagulant while stirring with the stirring rod, and is centrifugally projected by the horizontally rotating impeller installed at the lower end of the loading hopper. The shaped refractory is formed by mixing refractory aggregates containing refractory ultrafine powder, and the refractory ultrafine powder is volatile silica and/or calcined alumina. 2. The construction method of a monolithic refractory according to claim 1, wherein the centrifugal projection is performed at a constant angle in the circumferential direction. 3. The construction method of the monolithic refractory according to claim 1 or 2, wherein the monolithic refractory is further mixed with a dispersant. 4. The construction method of a monolithic refractory according to claim 1 or 2, wherein in the monolithic refractory, 50% by mass or less of refractory coarse particles are further compounded with respect to 100% by mass of the refractory aggregate. 5. The construction method of a monolithic refractory according to claim 1 or 2, wherein in the monolithic refractory, 10 mass% or less of metal wire is further mixed with respect to 100 mass% of the refractory aggregate. 6. The construction method of a monolithic refractory according to claim 1 or 2, wherein 3 to 10% by mass of construction water is added and kneaded to the monolithic refractory, and the slump value is based on the standard of JIS A1101 According to the measurement method, it is below 20cm.

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