JP3153209B2 - Refractory wet spraying method - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a wet spraying method for applying an irregular-shaped refractory as a lining of a molten metal container or a molten metal processing furnace or the repair thereof.

[0002]

2. Description of the Related Art Refractory linings for molten metal containers such as ladles, tundish (T / D), gutters, etc. are now more workable and more durable than those made of fixed bricks. The casting of irregular shaped refractories is generally performed.

[0003] However, the casting method requires operations such as installation, kneading, transporting, pouring, and de-framing of the core, so that it is difficult to automate all of them.

[0004] In addition, even in the case of repair, there is a part where pouring and repair cannot be performed, and even a possible part requires much time and has a problem in work efficiency.

For this reason, in recent years, a method of spraying an amorphous refractory directly onto a construction surface has been developed. Among them, water is added to the refractory material in advance, mixed and pumped, and the curing accelerator is pressurized with a spray nozzle. The wet spraying method, in which the refractory material is mixed with air and sprayed onto the construction surface, is particularly noted because it can further improve the workability by automation without lowering the quality and can also improve the efficiency of repairs Is starting to be.

That is, in this construction method, as shown in FIG. 8 (A), the refractory material W is sprayed with the spray nozzle X directed at right angles to the construction surface A, and as the construction proceeds, When the spray nozzle X moves in the direction of the arrow as shown in FIG. 8A, the rebound loss increases due to the rebound of the refractory material W due to the spray.

[0007] In the case of construction in the vertical direction shown in FIG. In the figure, B is a construction body.

In addition, in these spraying methods, the spray nozzle must be manually or manually directed toward the surface to be sprayed, and the working environment of the operator (heavy work, dusting).
There are also problems in terms of efficiency of construction, and in order to solve these problems, a spray construction method in which movement of a spray nozzle is automated has been used in recent years.

[0009] For example, Japanese Utility Model Application Laid-Open No.
In the spray nozzle described in Japanese Patent Publication No. 171556 (hereinafter referred to as the former publication), the base end side of the spray nozzle main body is supported by a spherical bearing, and the distal end side of the spray nozzle main body is eccentric to the spherical ring on the outer peripheral surface. By penetrating at least, the spherical ring can be rotated so that the tip side of the nozzle body draws an arc having a radius of eccentricity, which is always uniform even if the spraying direction of the spray nozzle changes. This is a content that allows a spraying pattern to be obtained.

In this spray application method, as a means for improving the durability of the amorphous refractory, a dense material having reduced pores by reducing the amount of water added during kneading is to be used. There is a problem that it is difficult to appropriately manage the pumping conditions and the spraying conditions.

As an example for solving this problem, there is JP-A-10-30885 (hereinafter referred to as the latter publication). According to this publication, the water content is 2 to 8 watts.
%, And the refractory kneaded and kneaded is sprayed onto the construction surface through a spray nozzle, and the spraying construction speed is 2 to 10 kg / Hr.
/ Cm ² and the thickness of the layer of the sprayed body formed by one scan of the spray nozzle is 10 to 120 mm.

[0012]

However, the prior art has the following problems. That is, 1) The spraying nozzle described in the former publication always obtains a uniform spraying pattern even if the traveling direction of the spraying nozzle changes, but the nozzle is eccentrically rotated, so that there is a lot of rebound loss and 50 mm or more. If the spraying is performed with a thickness of, the rebound loss due to the step between the construction surface and the raised construction body portion increases, which is not preferable.

2) In the normal spraying method described in the latter publication (the central axis of the spraying nozzle is perpendicular to the construction surface), if the construction thickness of one application exceeds 50 mm, the construction surface and the raised construction body part In this case, a step is formed, and the rebound loss increases, which is not preferable.

[0014] Further, it is difficult to increase the thickness of a single operation to 50 mm or more because it is blown perpendicular to the surface to be applied. To obtain an additional operation thickness, a thin layer having a thickness of less than 50 mm is sprayed in layers. There must be.

However, in this case, the construction body has a layered structure parallel to the working surface, which causes peeling during use, which is not preferable in terms of quality.

That is, the relationship between the thickness of one layer sprayed by the conventional spraying method as shown in FIG. 8 and the adhesion rate% is as shown in the graph of FIG. However, discharge amount: 3m ³
/ Hr, nozzle moving speed: 3.3 m / min, tap flow value: 190 mm, material: high alumina. As can be seen from this graph, setting the working thickness to 50 mm or more at one time causes a significant decrease in the adhesion rate.

The layer thickness of the sprayed construction formed by one scan of the spray nozzle is preferably 50 to 250 mm, more preferably 100 to 200 mm.

When the spraying thickness is less than 50 mm as described above, the height difference between the construction surface and the sprayed construction body is small, and a high adhesion rate can be obtained. However, when the thickness exceeds 50 mm, the drop is large and rebound loss increases to increase the adhesion. Since the rate drops sharply, it becomes necessary to perform angled spraying.
It is difficult in terms of a construction method that the layer thickness of the spray construction body formed by one scan of the spray nozzle exceeds 250 mm.

The present invention focuses on the above-mentioned problems of the prior art, and has a low rebound loss even when spraying an amorphous refractory mixed with low moisture, and has a layered structure parallel to the working surface of the construction body. It is an object of the present invention to provide a method for wet spraying an irregular-shaped refractory, which can eliminate a structure and can obtain a sprayable construction having a high durability and little peeling during use.

[0020]

According to the present invention, there is provided a spraying method for forming an object by spraying a refractory onto an inner surface of a molten metal container through a spray nozzle. The thickness of the spray construction body formed by one scan of the spray nozzle is 50 m
m or more, and the angle in the horizontal direction and / or the vertical direction with respect to the center axis of the spray nozzle and the spray surface is 10 ° with respect to the direction perpendicular to the spray surface.
The present invention is directed to a method for wet spraying of refractories in which spraying is performed within a range of up to 60 °.

The above-mentioned construction is to carry out automatic construction by an automatic spraying device.

At this time, the tap flow value of the refractory is preferably 150 to 250 mm.

[0023]

DESCRIPTION OF THE PREFERRED EMBODIMENTS The present invention will be described below with reference to embodiments shown in the drawings.

FIG. 1 schematically shows an automatic spraying apparatus 1 to which a method for wet spraying of an amorphous refractory according to the present invention is applied, and a mixer 2 for kneading a refractory material powder a and water b.
And a pump 5 for pumping the refractory c discharged from the mixer 2 to the spray nozzle 3 through the pipe 4.
A hardening accelerator supply means 6 for supplying a hardening accelerator d to the refractory c; and high-pressure air for mixing the hardening accelerator d with the refractory c in the spray nozzle 3 and blowing the mixture on the construction surface A. And a compressor 7 for supplying
2 and a nozzle moving means 10 shown in FIG. In the figure, B is a construction body, C is a perm brick, and D is a steel shell.

Here, the nozzle moving means 10 is, for example, an apparatus as disclosed in Japanese Patent Application Laid-Open No. Hei 10-212512 filed by the present applicant, which supports the spray nozzle 3 and can freely change the nozzle angle. A support mechanism 20 is provided.

The specific structure is shown below. A rail 12 is laid on the construction surface 11 to be repaired in a width direction above the construction surface 11, and a traveling carriage 14, which can be driven by a motor 13, on the rail 12.
Is mounted, and a pair of guide rails 1 fixed to the upper part of the traveling carriage 14 in a direction perpendicular to the traveling direction of the carriage.
5 and 15, on which a traversing carriage 17 which can be driven by an electric cylinder 16 is mounted. The rail 12 is laid using an overhead traveling crane or the like.
A support mechanism 20 is provided on the upper surface of the traversing carriage 17, one end of which is pivotally supported by a bearing 18 a by a pin 19, and the other end of which has a tilting table 21 operable around the pin 19. The tilting table 21 can be tilted by the expansion and contraction of an electric cylinder 22 supported on the upper surface of the traversing carriage 17 via a column 18b. On the upper surface of the tilting table 21, a turning table 24 is provided which can be rotated over a range of 360 ° by a motor 23. A cylindrical elevating frame 25 is inserted through the revolving base 24, and a pair of guide members 26, 26 provided outside the revolving base 24 is engaged with a pair of upper and lower guide rollers (not shown) provided on the revolving base 21 side. The rotation in the circumferential direction is regulated by the, and it is possible to move up and down.

A rack gear 27 is vertically fixed to the outer periphery of the elevating frame 25, and a pinion gear 28 and a motor 29 for rotating the pinion gear 28 are provided on the revolving base 21 side so as to mesh with the rack gear 27. Thus, when the pinion gear 28 rotates, the lifting frame 25 can be moved up and down via the rack gear 27 meshing with the pinion gear 28. The refractory c sent from the pressure pump 5 shown in FIG. 1 is transported by the pipe 4, and the refractory c is further transported into the material supply pipe 31 connected from the pipe 4. The material supply pipe 31 is connected to the lifting frame 25.
And is projected from the lower part of the elevating frame 25.

That is, as shown in FIG.
The lower portion is formed in a meandering portion 32 that protrudes and curves to one side, and the tip portion 32a is formed so as to face in the horizontal direction.

An upper end of a nozzle pipe 33 bent approximately 90 ° is rotatably connected to the distal end portion 32 a through a rotary joint 34, and a spray nozzle 3 is provided at the distal end of the nozzle pipe 33.

In FIG. 2, reference numeral 9a denotes an air hose, 9b denotes a binder hose, and tips 9a and 9b are respectively connected to the base 3a of the spray nozzle 3 shown in FIG.
Is mixed with a curing accelerator d. Reference numeral 35 in FIG. 2 denotes an electric cylinder, and reference numeral 36 in FIG. 3 denotes an arm of a nozzle pipe 33. When the electric cylinder 35 is operated, the arm 36 connected to a rod (not shown) can rotate around the rotary joint 34. Therefore, the spray nozzle 3 is rotatable at an arbitrary angle.

Next, the spraying method using the above-mentioned apparatus is performed by a nozzle moving means 10 provided at a working place by adding a refractory powder a and an appropriate amount of water b to a mixer 2 and kneading the refractory c. To the spray nozzle 3 set in the support mechanism 20 of the above, and an appropriate amount of a curing accelerator d is added to the refractory c.
Surface A while mixing with high pressure air (see Fig. 1)
In this case, the spray nozzle 3 is adjusted to a proper angle by rotation, and the refractory c is sprayed at a proper moving speed, so that the refractory c is applied to a constant thickness.

The refractory powder used at this time includes oxides such as alumina, silica, magnesia, zircon, zirconia and calcia, carbides such as silicon carbide, nitrides such as silicon nitride, aggregates such as carbon and graphite. Including species or multiple species. The refractory powder also has a curable inorganic material such as alumina cement, Portland cement, resin, etc. as a curing agent,
And organic matter, and may be added separately (eg, at the base of the nozzle).

The hardening accelerator is an auxiliary agent used for instantly losing the fluidity of the amorphous refractory when spraying the amorphous refractory and making the spraying possible.
Hydroxides such as calcium hydroxide, sodium hydroxide and potassium hydroxide, aluminates such as sodium aluminate, potassium aluminate and calcium aluminate, silicates such as sodium silicate and lithium silicate, phosphoric acid, phosphate, nitric acid , Nitrate, hydrochloric acid, chloride and the like. At the time of spraying addition, the curing accelerator is used in the form of a solution, a suspension, or a powder.

The water content to be added to the refractory powder is 2 wt% to 15 wt%.
wt% is preferable, and 5 wt% to 12 wt% is more preferable. If the content is less than 2 wt%, the flow resistance when the refractory is supplied to the transfer pipe rapidly increases, so that an excessive transfer pressure is required, and the spray nozzle and the transfer pipe are easily clogged, which is not preferable. Conversely, if the water content exceeds 15 wt%, the flow resistance decreases, but the porosity of the sprayed construction increases, and the strength and corrosion resistance deteriorate.

The material is discharged at an amount of 1 to 6 m ³ / Hr. If the discharge amount of the refractory sprayed on the construction surface is less than 1 m ³ / Hr, it takes a long time, the spraying operation efficiency is remarkably reduced, and the moisture in the spray layer formed for each scan of the spray nozzle is increased. It is desirable to set it to 1 m ³ / Hr or more because it causes a variation in the amount and the like.

If it exceeds 6 m ³ / Hr, the mixture of the refractory material and the curing accelerator at the spray nozzle becomes non-uniform, making it difficult for the refractory material to harden, the amount of addition increases rapidly, and the quality of the construction decreases. Therefore, it is desirable to set it to 6 m ³ / Hr or less.

The moving speed of the spray nozzle is 2 to 10 m / m
in. If the moving speed is less than 2 m / min, the spraying thickness is fixed, so that the material discharge amount is limited, the working speed becomes extremely slow, and the working efficiency is reduced. If it exceeds 10 m / min, on the contrary, the material discharge amount required to obtain the prescribed construction thickness exceeds 6 m ³ / Hr, and construction becomes difficult for the above-mentioned reason.

As described above, the thickness of the construction body is one layer or 50 layers.
By spraying with a plurality of spraying layers having a thickness of at least mm, it is possible to further improve the peeling and abrasion resistance of the spraying layer due to peeling, thermal spalling, and infiltration of slag and molten iron.

The conveying pressure of the kneaded refractory is 200 kgf
/ Cm ² or less. If it is more than 200 kgf / cm ² , the load on the equipment of the conveying pipe becomes excessive, the maintenance cost becomes high, and clogging easily occurs during pressure feeding, which is not preferable.

The addition amount of the curing accelerator is preferably from 0.1 wt% to 5.0 wt% based on the kneaded refractory. If the addition amount of the curing accelerator is large, the porosity increases and the dispersion of the construction increases. The addition amount is particularly preferably 0.1 wt% to 1 wt%. 0.1wt%
If it is less than 30, a sufficient curing promoting effect cannot be expected, and spraying cannot be performed. Further, if the curing accelerator is added in excess of 5.0 wt%, the quality characteristics of the sprayed construction are impaired, which is not preferable.

When the refractory is sprayed on the construction surface, the spray pressure at the tip of the spray nozzle is 3 kgf / cm ^{2 to} 10 kgf.
/ Cm ² is desirable. If it is less than 3 kgf / cm ² , the spraying capacity decreases, the apparent porosity increases, and the corrosion resistance decreases. In addition, a sufficient spray layer thickness cannot be formed, which causes a problem in corrosion resistance and the like. On the other hand, if it exceeds 10 kgf / cm ² , rebound loss occurs during spraying, increasing the apparent porosity of the construction layer, making it difficult to hold the spray nozzle during construction, and strengthening the spray mechanism. Is required.

The apparent porosity of the sprayed body after drying is 23.
% Is preferred. If it exceeds 23%, the corrosion resistance of the sprayed construction body to molten steel and slag is significantly reduced, and it is difficult to use it as a refractory for steelmaking and pig iron.

If the tap flow value of the refractory is less than 150 mm, the fluidity and the slipperiness are insufficient, so that the efficiency of suction of the material pump into the cylinder is remarkably deteriorated, so that the pumping becomes difficult and the rebound loss increases.

On the other hand, the reason why the tap flow value exceeds 250 mm is that an excessive amount of added water is added, and the quality of the sprayed construction body is deteriorated by excess water.

The tap flow value here is based on JIS R
It is a value obtained by the flow test method specified in 2521. Specifically, the upper inner diameter is 70 mm, the lower inner diameter is 100 mm, and the height is 60 mm.
Put the frustoconical steel container on the tap flow table,
After filling the steel container into the steel container in two layers with a packing rod from above, the steel container was withdrawn upward in a few seconds, and given a falling motion 15 times in 15 seconds to spread the castable. The length (mm) of the diameter is measured in the direction recognized as the maximum and the direction perpendicular to the direction. A value obtained by rounding the average value of these two lengths to an integer is set as a tap flow value.

In the present invention, in the case where the spraying nozzle 3 at an angle to the working surface A in the plan view shown in FIG. Θ (horizontal direction) with the direction perpendicular to the construction surface
When the angle θ with respect to the direction perpendicular to the center axis OO of the spray nozzle 3 and the direction perpendicular to the spraying surface (construction surface) A exceeds 60 °, the angle becomes shallow. As it passes, it becomes oblique, and rebound loss increases.

On the other hand, when the angle θ is less than 10 °, rebound loss occurs due to the step between the construction surface and the raised construction body, as in the case of spraying perpendicularly to the construction surface. Increase. In addition, the graph of FIG. 6 shows a discharge amount: 3 m ³ / Hr, a parallel spraying on a working surface, a nozzle vertical direction: 35 °, a nozzle moving speed: 3.3 m / min, a tap flow value: 192 mm, a material: high alumina working thickness. This was obtained under the condition of 200 mm.

In the elevation view shown in FIG. 4B, the angle φ with respect to the direction perpendicular to the center axis OO of the spray nozzle 3 and the vertical spray surface (construction surface) A is shown in FIG. As shown in the graph of the adhesion ratio% with respect to the angle φ (vertical direction) between the nozzle center axis and the work surface, the work is performed when the angle φ between the center axis of the spray nozzle 3 and the spray surface A in the vertical direction exceeds 60 °. The angle is too shallow with respect to the surface, so that the air blows obliquely and rebound loss increases. On the other hand, the angle φ is 10 °
Also in the case of less than, the step between the construction surface and the raised construction body causes oblique blowing, and rebound loss increases.

The graph in FIG. 7 shows the discharge amount: 3 m ³ / H
r, construction surface parallel movement spraying, nozzle horizontal direction: 35 °,
Nozzle movement speed: 3.3 m / min, tap flow value:
195 mm, material: high alumina A thickness of 200 mm.

Accordingly, from the results of the graphs of FIGS. 6 and 7, if the angle between the nozzle center axis and the horizontal and / or vertical working surface is in the range of 10 ° to 60 °, a high adhesion rate can be obtained, This range proved to be the most appropriate.

(Example) Next, with reference to Table 1, a case in which the wet spraying method of the amorphous refractory according to the first embodiment of the present invention is applied to a ladle, which is an example of a construction surface, will be described. explain.

[Table 1]

As shown in the first embodiment, alumina 9
To a refractory powder composed of 2%, silica 1%, magnesia 5%, and cement, kneading water was added by 7% over the outside, mixed and kneaded with a mixer to obtain a refractory for spraying construction.

Next, the material is continuously pumped at a transport pressure of 50 kg / cm ² by a material pressure pump, and a curing accelerator is added to the refractory by compressed air at a spraying speed of 4 m ³ / hr with respect to the refractory. Was supplied to the spray nozzle at the following addition amount.

In this case, the spray nozzle and the spraying surface were angled at 30 ° in the vertical direction and 35 ° in the horizontal direction. Here, the spray nozzle was moved while supported by an automatic spray device. The construction body is a single layer and the construction thickness is 150m
m, the adhesion rate was 96% or more, and the spraying operation with less dust could be performed.

In the examples, alumina 88%, silica 1
%, Magnesia 9%, and alumina-magnesia refractory powder consisting of alumina cement are kneaded at a water content of 7% to form a refractory for spraying, and the spraying is performed by an automatic spraying device. The nozzle has an angle of 40 ° in the advancing direction (horizontal direction) and an angle of 40 ° in the vertical direction, has a thickness of 200 mm formed by one scan, a spraying speed of 4 m ³ / hr, and a moving speed of the spray nozzle of 3 .4m /
min and spraying was carried out to obtain an alumina / magnesia construction. At that time, the adhesion ratio was 97% or more, and good workability and a work body were obtained.

In this embodiment, the spraying nozzle was sprayed with the same material composition as above, with the vertical angle of the spray nozzle being 0 ° and the horizontal angle being 20 °. there were.

Further, in the embodiment, the horizontal angle of the spray nozzle is set to 0 ° and the vertical angle is set to 5 with the same material composition.
When sprayed at 5 °, this also gave an adhesion of 93%.

In Table 1, is a conventional example. In spite of using the same material as the above, the spraying nozzle support angle at the time of spraying is set to be perpendicular to the conventional work surface, and the work thickness is 100 mm. As a result, there was a step between the construction surface and the spray construction body surface. The rebound loss was extremely increased due to spraying on the step surface, and the adhesion rate was reduced to 84%.

In the conventional example, the material discharge amount is 1.5 m ³
/ Hr, spraying nozzle moving speed 8.3 m / min, nozzle angle is 40 ° in moving direction (horizontal direction), and 40 in vertical direction
Although the construction is performed in °, the thickness of the construction body is 30 mm, so the step between the construction surface and the construction body is small, and if the spray nozzle is angled, it will be sprayed obliquely to the construction surface, and this will rebound Adhesion rate of 85 due to increased loss
% And the workability was very poor.

Although the embodiment of the present invention has been described above, the present invention is not limited to such an embodiment, and any change in conditions without departing from the gist is within the scope of the present invention.

In the embodiment of the present invention, the case of cold spraying with a ladle has been described. For example, a secondary smelting furnace such as a blast furnace gutter, a hot metal pot, a mixed iron wheel, T / D, RH, etc. Application to a CAS immersion tube or the like is also possible, and the present invention can be applied without being limited to conditions such as hot spraying and cold spraying.

[0062]

As described above, the present invention has the following effects. 1) According to the wet spraying method according to the first aspect, the discharge amount of the sprayed refractory from the spray nozzle, the angle of the spray nozzle, the spray nozzle, Since the moving speed of the refractory from the spray nozzle and the scattering speed of the refractory from the spray nozzle are within the specified range, and the layer thickness of the sprayed construction body formed by one scan of the spray nozzle is within the specified range, the rebound loss is reduced. It is possible to obtain a uniform construction body having good durability and having a high packing density, not having a layered structure parallel to the operating surface causing peeling, and having a reduced packing density. Further, since the spraying object can spray 50 mm or more in one scan, one or more layers can be applied to most molten metal containers. 2) If the wet spraying is automatically performed by using an automatic spraying device, the spraying can be performed reliably and efficiently. 3) According to the wet spraying method of claim 3, since the tap flow value of the refractory is specified in a specific range, the spraying workability is properly maintained, and the quality of the sprayed construction body is improved. Variation can be further suppressed.

[Brief description of the drawings]

FIG. 1 is a schematic diagram of a spraying apparatus to which a method for wet spraying of refractories according to the present invention is applied.

FIG. 2 is an elevational view of a spray nozzle support mechanism and moving means used in the spray device of FIG. 1;

FIG. 3 is an enlarged view of a spray nozzle portion of FIG. 2;

4A and 4B show a method for wet spraying a refractory according to claim 1 of the present invention, wherein FIG. 4A is a plan view and FIG.

FIG. 5 is a graph showing a relationship between a single-layer spray thickness and an adhesion rate by a conventional spray application method.

FIG. 6 is a graph showing a relationship between an adhesion rate and an angle (horizontal direction) between a central axis of a nozzle and a direction perpendicular to a construction surface according to the present invention.

FIG. 7 is a graph showing a relationship between an adhesion rate and an angle (a vertical direction) between a nozzle center axis and a direction perpendicular to a construction surface according to the present invention.

8A and 8B show a conventional spraying method, wherein FIG. 8A is a plan view and FIG. 8B is a side view.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 Automatic spraying device 3 Spray nozzle 10 Nozzle moving means 20 Nozzle support mechanism A Work surface B Work body

──────────────────────────────────────────────────続 き Continuation of the front page (56) References JP-A-10-30885 (JP, A) JP-A-59-161680 (JP, A) JP-A-5-112807 (JP, A) JP-A-6-106 323747 (JP, A) (58) Fields investigated (Int. Cl. ⁷ , DB name) F27D 1/16 B22D 41/02 C04B 35/66 F27D 1/00

Claims (4)

(57) [Claims] 1. A method for forming a construction by spraying an irregular-shaped refractory through a spray nozzle, wherein the sprayed construction body is formed by a single scan of the spray nozzle. One or more layers having a thickness of 50 mm or more, and spraying is performed by setting the angle in the horizontal direction and / or the vertical direction with respect to the direction perpendicular to the center axis of the spray nozzle and the spray surface in the range of 10 ° to 60 °, respectively. Wet spraying method of refractories characterized by performing. 2. A wet spray installation method according to claim 1 refractory according to an automatic construction by the construction automatic spraying device. 3. The tap flow value of the refractory is 150-2.
The method for wet spraying refractories according to claim 1 or 2, which is 50 mm. 4. The method for wet spraying of refractories according to claim 1, wherein the sprayed body has one or more sprayed layers having a thickness of 50 mm or more.