JPH1054669A - Forming method of refractory furnace structure - Google Patents

Abstract

PROBLEM TO BE SOLVED: To lessen scatting of dust to the periphery, to increase the bulk specific gravity of a constructed body and to enable use of porcelain earath for a portion to be brought into contact with molten metal, by a method wherein the porcelain earth wherein a quick setting agent is mixed together with compressed air is sprayed on a place of construction from a spray nozzle and thereby a spayed layer heaving a densified quality is formed as a lining of a heat insulating layer. SOLUTION: A furnace layer (the second layer) 15 and a furnace layer (the first layer) 16 are constructed of a undraped refractory composition by spraying and a furnace body is formed thereof. A porcelain earth which is prepared by adding water to the unshaped refractory composition containing refractory aggregate, refractory powder and a small quantity of dispersing and by kneading and which has self-fluidizing properties is sent under pressure to a site of construction by a pressure sending pump and a pressure sending piping. A necessary quantity of quick setting agent is injected, in addition to compressed air, into the porcelain earth and the fluidity of the earcelain earth sprayed in a place of construction having a heat insulating layer from a spray nozzle lowers quickly after the injection. Therefore a moisture more than needed is prevented from being absorbed by the heat insulating layer and it can be prevented from flowing down, in the course of construction, from a wall surface whereon the porcelain earth is sprayed.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method of forming a refractory furnace used for contacting a molten metal having both excellent workability and durability.

[0002]

2. Description of the Related Art In recent years, the use of amorphous refractories has been increasing in the construction of various furnaces from the viewpoint of labor saving of construction work.
FIG. 6 shows a refractory furnace structure used in a melting furnace and a holding furnace for molten metal. The refractory furnace structure shown in FIG. 6 has various shapes such as a cylindrical shape and a box shape.
A refractory is built inside a steel casing (not shown) which includes a side wall and a ceiling, and has a refractory furnace structure. Numeral 10 indicates a molten metal liquid level when the apparatus is operated. In addition, auxiliary functions such as a raw material insertion port, a molten raw material outlet, a heating burner, and a flue of burner exhaust gas are not shown.

[0003] The furnace bottom part 1 is poured while insulated castable 1-1 is applied (hereinafter referred to as "vibration construction"), and refractory castable 1-2 is subjected to vibration construction.
A plurality of precast blocks 1-4 (high-strength, dense castables are kneaded with a small amount of water in advance on a refractory castable 1-2 to form a kneaded clay, and the kneaded clay is dried and formed in a mold having a predetermined shape. ) Are arranged at intervals, and a high-strength dense castable 1-3 is vibrated and integrated into the gap between the precast blocks 1-4. Here, the shape of the furnace bottom 1 can be designed not only in a plane but also in a shape suitable for holding the molten metal, such as a spherical shape.

[0004] When the hearth 1 has a generally frusto-conical shape that opens upward or a spherical shape that opens upward, if the fluidity of the material is too large, dripping will occur during vibration construction. 1-1, when the refractory castable 1-2 is not very fluid and does not show fluidity and is solidified in a dumpling shape by hand and adhered to the construction part, or when the clay is a water mass that can be vibrated, It was necessary to attach a form fitting to the shape of the hearth lining, and to perform a predetermined vibration work, which was very labor-intensive and required a great deal of labor.

[0005] The side wall 2 is constructed by vibrating a heat-insulating castable to form a heat-insulating layer 2-1 and vibrating a refractory castable 2-2. Finally, a high-strength dense material in contact with the upper surface 10 of the molten metal. A high-strength dense castable or a refractory castable 2-4 which is located above the castables 2-3 and 2-3 and does not contact the molten metal is vibrated.

[0006] When the heat insulating layer 2-1 is to be vibrated, first, a mold (a wooden frame or a metal frame) is attached to the inner surface of the furnace. The formwork is
It is necessary to reinforce the formwork from a steel structure (not shown) of the side wall portion 2 through a well-known separator bolt or the like used in civil engineering or the like, if necessary.

Next, predetermined water is put into the castable, kneading is performed by a mixer, the clay is formed into a flowable clay by vibration, and then put into a mold. Vibration is performed while applying vibration with a rod-shaped vibrator or the like. . Furthermore, after completing the vibration construction, after a curing period of about 10 to 24 hours,
The unrefractory refractory is developed to have a removable strength, and then the above-described mold is removed.

When the refractory castable 2-2, the high-strength dense castable 2-3, and the high-strength dense castable or the refractory castable 2-4 are vibrated, a mold is used in the same procedure as the heat insulating layer 2-1. Implemented.

The ceiling 3 is constructed by welding a known Y anchor or the like to a steel structure of the ceiling 3 (not shown) in order to prevent the refractory from falling off.

First, a refractory castable 3-2 is mounted on a lower surface (furnace ceiling surface) of the refractory castable 3-2 via a well-known separator bolt or the like, and then a mounted formwork. Vibration construction is performed after the kneaded kneaded clay is put on the top.
Here, the kneaded clay is injected by opening a small manhole in a steel structure (not shown) of the ceiling portion 3, but when a large number of manholes are provided, the strength of the steel structure is reduced, so that the number is reduced as much as possible (for example, 1 to 4 places), and the operation of applying vibration is to vibrate the mold section from inside the furnace with a trowel vibrator, etc., so that it is difficult to apply sufficient vibration to the material and the strength of the mold is weak. It is difficult to give an excessive vibration, and it is necessary to increase the fluidity of the material and to carry out the vibration construction with a small vibration. For this reason,
The amount of water to be added to the castable becomes large, and the strength after construction tends to decrease, causing problems such as difficulty in obtaining sufficient refractory performance.

Finally, a heat-insulating castable 3-1 is inserted through a manhole into a region between the steel structure (not shown) of the ceiling 3 and the refractory castable 3-2, and vibration is performed.

As the characteristics of the castables used, the high-strength, dense castables 1-3, 2-3 and the precast block 1-4 are required to have corrosion resistance and penetration resistance with the molten metal because they come into contact with the molten metal. Identical chemical performance is required.

The high-strength dense castable 2-4 and the refractory castable 3-2 used in the ceiling do not come into direct contact with the molten metal, and therefore have a higher corrosion resistance and permeation resistance than 1-3, 2-3 and 1-4. The required performance may be slightly lower, but heat resistance is required.

As described above, when the conventional refractory furnace structure is implemented by vibrating construction, it is necessary to attach and remove the formwork, which requires a great deal of time and labor. Since the kneaded clay such as high-strength dense castables is very hard and difficult to transport mechanically by pumping, etc., a large amount of labor such as manually transporting kneaded kneaded clay in a bucket in a bucket is required. Had the problem of requiring

On the other hand, spraying an amorphous refractory composition has the advantage that the construction method can be labor-saving compared to a casting method such as a vibration casting method because a formwork is not required. Therefore, a method of spraying an amorphous refractory has conventionally been used.

The conventional spraying construction method is a so-called dry or semi-dry spraying construction method.
That is, the dry amorphous refractory powder composition or the amorphous refractory powder composition is mixed with an amount of water that does not exhibit fluidity and the wet clay is compressed air as a carrier to the construction site with piping. The water is transported and sprayed from the spray nozzle by injecting the water required by the irregular-shaped refractory or the insufficient water by the spray nozzle.

However, according to such a method, fine particles of the refractory powder in the clay of, for example, 0.1 mm or less in the amorphous refractory powder composition are sprayed in a dispersed state and in an insufficiently wet state. Because it is constructed, a lot of air is taken into the clay of the spray-formed irregular-shaped refractory, and as a result, the molded body of the spray-formed irregular-shaped refractory is cast and cast. The porosity is large (the bulk specific gravity is small) as compared with the construction body of No. 1, and the refractory properties such as corrosion resistance are inferior to the extent that the porosity is large. Therefore, it has not been used in the refractory furnace structure for the purpose of coming into contact with the molten metal.

In particular, when a heat insulating layer is provided as an outer layer of the furnace, forming a dense spraying layer directly inside the heat insulating layer generally requires that the heat insulating layer be porous and use a spraying material. The moisture of certain amorphous refractory compositions is easily absorbed,
It is difficult to form a crack-free dense layer, and it has not been implemented so far.

[0019]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above-mentioned problems of the prior art and to provide an amorphous refractory,
It is possible to save more labor during construction, reduce scattering of dust to the surroundings, and reduce the porosity of the construction body, its bulk specific gravity is large, it has excellent characteristics as a refractory, and it is used in parts that come into contact with molten metal It is an object of the present invention to provide a refractory furnace structure which can be used.

[0020]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems, and has a fire-resistant heat-insulating layer provided on the outside of a furnace, and a fire-resistant aggregate, a fire-resistant powder, Amorphous refractory composition containing a dispersant, kneaded clay having self-fluidity kneaded by adding water, is pumped to a construction site by a pump and a pumping pipe, and compressed air injection provided downstream of the pumping pipe. Compressed air and the required amount of quick-setting agent are injected into the kneaded clay from the inlet and the quick-setting agent injection port, respectively, and the kneaded material with the quick-setting agent mixed with the injected compressed air is connected to the tip of the kneaded material by a nozzle pipe. An object of the present invention is to provide a method for forming a refractory furnace structure, comprising forming a dense sprayed layer on a lining of a heat insulating layer by sending a kneaded material to a construction site from a spraying nozzle.

The features of the refractory furnace structure of the present invention include a hearth, a furnace wall, and a ceiling. A heat insulation layer is provided on the outside of the furnace, and at least one furnace inner layer is provided on at least a part of the inside of the furnace. The furnace inner layer is formed by spraying with the above-mentioned amorphous refractory composition to form a furnace body.

The refractory furnace structure formed according to the present invention will be described with reference to FIG. The refractory furnace structure shown in FIG. 1 includes a hearth portion 11, a furnace wall portion 12, and a ceiling portion 13, and the outer shell portion has an unillustrated steel shell structure. Note that, depending on the method of using the refractory furnace structure, a structure in which the ceiling portion 13 is removable or a structure having no ceiling portion may be used.

A typical refractory furnace structure of the present invention has a three-layer structure of a porous heat insulating layer 14, a furnace inner layer (second layer) 15, and a furnace inner layer (first layer) 16 from the outside of the furnace toward the inside of the furnace. Consisting of
Each layer has a structure connected to the hearth 11, the furnace wall 12, and the ceiling 13. A Y anchor or the like is attached to the furnace wall portion 12 and the ceiling portion 13 from a steel structure (not shown).

The heat insulating layer 14 is made of a usual insulating brick lining,
Spraying or casting with lightweight amorphous refractories (lightweight and highly heat-insulating irregular refractories blended with porous refractory aggregates, vermiculite, etc.) or pasting of ceramic fiber molded boards However, it is preferable to perform spraying work that is easy to perform, that is, it takes time and effort to install and remove the formwork in vibration work, and in the pasting work for the board, It is not preferable because it takes time and effort to process the board in order to attach the board, and harmful fibers and the like are scattered when the board is processed.

As the spraying method, a known dry spraying method can be used. More preferably, when spraying, a lightweight amorphous refractory is mixed with water enough to wet the refractory material, and the known dry spraying method is used. The amount of dust generated can be reduced by carrying out pneumatic transportation by means of a device and performing semi-dry spraying in which the remaining water is sprayed after addition of the remaining water at the tip nozzle. In addition, wet-type spraying, in which a predetermined amount of water is mixed into a lightweight irregular-shaped refractory, thoroughly kneaded, and then pressure-fed by a squeeze pump, etc., and then injects and blows out predetermined air at the tip nozzle, reduces the amount of dust even more than semi-dry spraying can do.

In the present invention, the furnace inner layer (second layer) 15 and the furnace inner layer (first layer) 16 are formed by spraying with an amorphous refractory composition to form a furnace body, that is, a refractory aggregate. Amorphous refractory composition containing refractory powder and a small amount of dispersant, kneaded clay having self-fluidity kneaded by adding water, is pumped to a construction site by a pump and a pumping pipe,
Compressed air and a required amount of quick-setting agent are injected into the kneaded material from the compressed air injection port and the quick-setting agent injection port provided at the downstream portion of the pressure feed pipe, respectively. Is sent to a spray nozzle connected to the tip of the nozzle pipe through a nozzle pipe, and the kneaded material is sprayed from the spray nozzle to a work site (hereinafter referred to as dense spraying work).

Here, since the furnace inner layer (first layer) 16 is used in a portion that comes into contact with the molten metal, it needs properties such as corrosion resistance and permeation resistance, and requires a dense structure. The eye 15 is used for the purpose of preventing the molten metal from reaching the heat insulating layer 14 and further to the steel shell structure when the furnace inner layer (first layer) 16 is damaged and the molten metal enters, so that the short-term Erosion resistance and permeability are required, and a dense structure is required to some extent.

The furnace inner layer (second layer) 15 and the furnace inner layer (first layer) 16 having such a dense structure are made possible by the above-mentioned spraying, and are necessary in the conventional casting according to the present invention. In addition, the work of mounting the form, waiting for curing before removing the form, removing the form, and the like, and eliminating the form and the materials for attaching these forms are no longer required, and the construction period and construction costs can be extremely reduced.

The furnace inner layer (second layer) 15 provided in the refractory furnace structure is not always essential, and the design temperature of the outer shell of the furnace (usually 50 to 250) in the refractory furnace structure during operation.
C.), a two-layer structure including a heat insulating layer 14 and a furnace inner layer (first layer) 16, or a furnace inner layer (second layer) 1.
5 may be entirely or partially substituted by a fixed refractory brick or the like. Further, the heat insulating layer 14 may have a multi-layer structure made of materials having different thermal conductivities, or the furnace inner layer may have a metal wetted portion,
In addition, it is also possible to use a different material for lining at the non-metal contact portion.

FIG. 2 shows another preferred embodiment of the refractory furnace structure formed according to the present invention, in which a heat insulating layer 17 covering the hearth 11, the furnace wall 12, and the ceiling 13, the hearth 11 and the furnace wall are provided. The inner layer (second layer) 18 disposed on the inner side of the heat insulating layer 17 over the heat insulating layer 12, and the liquid contact disposed on the inner side of the furnace inner layer (second layer) 18 over the lower part of the hearth 11 and the furnace wall 12. Furnace inner layer (first layer) 19, ceiling 13 and furnace wall 1
The upper part 2 is composed of a heat insulating layer 17 of the ceiling part 13 and a non-wetted part furnace inner layer (first layer) 20 disposed inside the furnace inner layer (second layer) 18 of the furnace wall 12. Here, a joint 21 between the wetted part furnace inner layer (first layer) 19 and the non-wetted part furnace inner layer (first layer) 20 is provided above the molten metal liquid surface 22 during operation of the refractory furnace structure.

In FIG. 2, the ceiling portion 13 not in contact with the molten metal
Without the furnace inner layer (second layer)
Inner layer (first layer) 19 and liquid metal surface 2
This is an example in which a non-liquid-contacting furnace inner layer (first layer) 20 not in contact with No. 2 is densely sprayed with an amorphous refractory composition having a different composition.

Further, the furnace inner layer (first layer) 20
Only the ceiling part 13 may be densely sprayed with an amorphous refractory composition having a different composition, and the overall material cost can be made easier by changing the material composition according to the use conditions. The seam may be simply constructed by inserting a simple break (for example, a wooden partition plate is installed at a predetermined splicing position and fixed from a peripheral anchor or the like).

FIG. 3 shows another preferred embodiment of the refractory furnace structure formed by the present invention, which is constituted by a hearth section 11, a furnace wall section 12 and a ceiling section 13 and extends from the outside of the furnace toward the inside of the furnace. It has a two-layer structure of a heat insulating layer 23 and a furnace inner layer 24, and each layer has a structure connected to the hearth portion 11, the furnace wall portion 12, and the ceiling portion 13. In such a structure, particularly, a portion in contact with the molten metal is formed. It is required that the material of the furnace inner layer 24 is hardly cracked for a long period of time.
4 has excellent features such as the number of construction steps can be greatly reduced by performing dense spraying.

The spraying method for forming such a dense sprayed layer will be described below. The main feature of the spraying construction method of the present invention is that the clay of the amorphous refractory having self-fluidity is pressure-fed to a construction site by a pressure pump and a pressure pipe. According to this method, the kneaded clay of the irregular-shaped refractory which has been previously mixed with the required moisture can be sent to the construction site by the pressure pump and the pumping pipe. The distribution of water is even, and there is almost no air accompanying the particles around the kneaded material until the compressed air is injected, and most of the air bubbles that are entrained when the compressed air, which is a carrier, are injected into the kneaded material. Is released from the kneaded clay at the time of spraying construction, and as a result, a construction body of an amorphous refractory having a small porosity and a large bulk specific gravity is obtained.

In the spraying method of the present invention, in addition to the compressed air, a required amount of quick-setting agent is injected into the kneaded material, and is sprayed from the spray nozzle to the work site having the heat insulating layer via the nozzle pipe. The fluidity of the kneaded material rapidly decreases after being poured. Because of this, not only is the moisture absorbed by the insulation layer unnecessarily,
For example, even when the clay is sprayed on a vertical wall, the clay can be applied without flowing down from the sprayed wall. Further, since the spray nozzle is connected to the tip of the nozzle pipe, only one pipe is required to be connected to the spray nozzle, and the operation of moving the spray nozzle up, down, left, and right is easy. Further, preferably, the nozzle pipe is made flexible and the nozzle pipe is easily bent, so that the spraying work by hand can be facilitated.

The injection point of the quick-setting agent is preferably located downstream of the compressed air inlet or at the same position as the compressed air inlet. The kneaded material after the quick-setting agent has been rapidly hardened is sent to the spray nozzle through the nozzle pipe in a state where it is rapidly hardened, and is sprayed from the spray nozzle. The clay after injecting the quick setting agent is
Turbulent agitation during passage through the nozzle pipe causes the powder to be more well dispersed in the clay, and as a result, the required amount of quick-setting agent injected into the clay can be reduced. The length of the nozzle pipe is preferably 100
The effect of turbulent agitation can be obtained by setting the diameter to at least mm.

If the nozzle piping is not provided or the quick-setting agent injection port is provided in the spray nozzle portion, poor dispersion or quick-setting failure of the quick-setting agent may occur, causing dripping of the clay after spraying,
It is not preferable to inject a large amount of quick-setting agent in order to prevent this, because it causes blockage at the spray nozzle portion or causes deterioration in refractory performance.

The pressure-feeding pipe and the nozzle pipe move at positions sprayed manually, but the pipe is 50 A or more (JIS-G3) to reduce the pressure-feeding load to the pump.
452, the same applies hereinafter) is preferable, and when the inside of the pipe is filled with the clay, the weight becomes considerable.

Here, the injection point of the quick-setting agent is provided downstream of the injection port of the compressed air, more preferably at least 1 m downstream, so that the clay in the pipe downstream from the injection port of the compressed air is in an air-fed state. Therefore, the piping weight is reduced, and handling by hand becomes easy.

If the injection point of the quick-setting agent is located at the same position as the injection port of the compressed air, the air-conveying load section of the kneaded clay after the quick-setting only needs to be at the nozzle pipe portion, and the amount of air to be injected can be reduced.
In particular, since the construction is performed with a low amount of water, the amount of dust generated during spraying construction can be reduced. Here, the pressure feed pipe upstream of the nozzle pipe is filled with kneaded material and becomes heavy.
It is preferable to be around 0A.

In a preferred embodiment in which the injection point of the quick-setting agent is located at the same position as the injection port of the compressed air, a part or all of the compressed air injected into the kneaded material is used. You. In particular, when all of the compressed air injected into the kneaded material is used to inject the quick-setting agent, the compressed air is injected into the kneaded material through a common pipe together with the quick-setting agent. It can save its own piping to inject.

In the present invention, it is preferable to evaluate the fluidity of the clay by using a cone at room temperature of about 20 ° C. That is, the kneaded material immediately after kneading by adding water of about 20 ° C. to the powder composition, immediately after kneading into a cone-shaped cone having an upper end inner diameter of 50 mm, a lower end inner diameter of 100 mm, and a height of 150 mm and open upper and lower ends. The kneaded material is poured and filled, and the cone shape is pulled out upward and left for 60 seconds, and is indicated by a spread diameter (average value obtained by measuring spread in two directions, hereinafter referred to as a flow value).

If the flow value is 165 mm or more, the kneaded clay exhibits self-fluidity. However, it is necessary to be able to easily and stably send the kneaded clay kneaded by the pressure pump and the pressure pipe to the construction site, and the flow value of the clay kneaded by the pressure pump to be 180 mm or more, and further 200 mm or more. Is preferred. If the clay having a large flow value is used, the suction resistance of the pressure pump and the flow resistance in the pressure pipe can be reduced, the diameter of the pressure pipe can be reduced, and the long path pressure of the clay can be realized.

The amorphous refractory composition used in the method for forming a refractory furnace structure of the present invention contains a refractory aggregate, a refractory powder and a small amount of a dispersant.

Examples of the refractory aggregate include alumina, bauxite, diaspore, mullite, ban shale, chamotte, quartzite, pyrophyllite, sillimanite, andalusite, chromite, spinel, magnesia, zirconia, zircon, chromia, One or more selected from carbon such as silicon nitride, aluminum nitride, silicon carbide, boron carbide and graphite, titanium boride and zirconium boride can be preferably used, but not limited thereto, and known metal oxides and metal carbides , Metal nitrides, metal borides, and composites thereof can be used as appropriate.

As the refractory powder, alumina cement,
Alumina, titania, bauxite, diaspore, mullite, ban earth shale, chamotte, silica, pyrophyllite, sillimanite, andalusite, chromite, spinel, magnesia, zirconia, zircon, chromia, silicon nitride, aluminum nitride, aluminum nitride, silicon carbide , And at least one selected from amorphous silica such as boron carbide, titanium boride, zirconium boride, and fumed silica and having an average particle size of 30 μm or less.

As a part of these refractory powders, it is preferable to use ultrafine powder having an average particle size of 10 μm or less, preferably 5 μm or less, such as alumina or fumed silica. The use of ultrafine powder of alumina or fumed silica can reduce the amount of water mixed with the composition, and can impart good fluidity to the kneaded clay.

When alumina cement is used as a part of the refractory powder, the alumina cement contributes to the bonding of the refractory for casting, and the construction can provide practical strength in a wide range from normal temperature to high temperature. .

As the dispersant used to impart fluidity to the kneaded clay, at least one selected from polymetaphosphates, polycarboxylates, polyacrylates and β-naphthalenesulfonates can be preferably used. .
The dispersant is preferably added in an amount of 0.02 to 1 part by weight based on 100 parts by weight of the total amount of the refractory aggregate and the refractory powder in the composition.

The amount of water mixed with the composition varies depending on the specific gravity and porosity of the refractory aggregate and refractory powder contained in the composition. There is a lower limit to the amount of water that can impart fluidity to the kneaded clay, and usually, a water amount of 4 parts by weight or more is required for 100 parts by weight of the total amount of the refractory aggregate and the refractory powder. Also,
In order to reduce the porosity of the refractory after construction and ensure good physical properties as a refractory, the amount of water mixed into the composition is 100 parts by weight of the total amount of the refractory aggregate and the refractory powder. Is preferably 15 parts by weight or less with respect to If the amount of water mixed with the composition is large, the refractory aggregate tends to settle, and the applied refractory tends to be heterogeneous.

As a quick setting agent to be injected into the kneaded material, a quick setting agent of an aqueous solution can be used. However, in order to secure a good refractory property by keeping the amount of water in the kneaded material to be sprayed to a minimum. , Preferably a powder. The powder quick-setting agent is preferably injected into the kneaded material from the quick-setting agent injection port using compressed air as a carrier. When injecting the quick setting agent of the aqueous solution into the kneaded clay, it is preferable to use an aqueous solution that is as dense as possible. The quick-setting agent is preferably injected into the kneaded material using compressed air as a carrier so as to be uniformly dispersed.

Examples of the quick setting agent include sodium aluminate,
Aluminates such as potassium aluminate and calcium aluminate, carbonates such as sodium carbonate, potassium carbonate, sodium bicarbonate and potassium bicarbonate, sulfates such as sodium sulfate, potassium sulfate and magnesium sulfate, CaO.Al ₂ O
_{3, 12CaO · 7Al 2 O 3} , CaO · 2Al 2 O 3, 3CaO · Al 2 O
_{3, 3CaO · 3Al 2 O 3} · CaF 2, 11CaO · 7Al 2 O 3 · CaF 2 Calcium aluminate such as, calcium oxide, one or more may be used selected from calcium hydroxide and their composites or mixtures .

Since the required amount of the quick-setting agent varies to some extent depending on the type of the quick-setting agent, the injection amount is adjusted according to the type of the quick-setting agent and the length of the nozzle pipe after the quick-setting agent is injected. Is preferred.

The injection amount of the quick setting agent is 0.00 on a dry basis with respect to 100 parts by weight of the powder composition excluding water and the dispersant.
Preferably, the amount is 5 to 3 parts by weight. If the amount is less than 0.05 parts by weight, even if the quick-setting agent has good performance, the quick-setting speed is insufficient, and the clay that has been sprayed and formed will flow down.
If a large amount is added in excess of parts by weight, the composition hardens rapidly and makes spraying work difficult, and the performance as a refractory such as heat resistance and corrosion resistance deteriorates.

As a commercially available pump, it is preferable to use a piston type or squeeze type pump. The squeeze type refers to a pump or the like that presses a kneaded material by pressing an elastic tube with a roller. As these pumps, it is preferable to use a pump having a plurality of tubes or a plurality of pistons so as to reduce the pulsation of the clay to be pumped.

[0056]

Embodiments of the present invention will be described below.

Example 1 Al ₂ O ₃ and SiO _{2 were} used as refractory aggregates.
And Fe ₂ O ₃ content of 89% by weight and 7% by weight, respectively
And 1.3% by weight with a particle size of 1.68 to 5 mm
A bauxite aggregate composed of coarse particles having a coarse particle diameter of 0.1 to 1.68 mm and coarse particles having a particle diameter of 0.02 to 0.1 mm and an average particle diameter of 0.02 mm was used.

(Examples 2 and 3) Al ₂ O ₃ ,
The contents of SiO ₂ and Fe ₂ O ₃ were 43% by weight and 53%, respectively.
% And 0.9% by weight, having a particle size of 1.68 to
5 mm coarse particles, medium particles having a particle size of 0.1 to 1.68 mm, and 0.02 to 0.1 mm with an average particle size of 0.03 m
m-grained chamotte aggregate was used.

As the refractory powder, the contents of Al ₂ O ₃ and CaO are 55% by weight and 36% by weight, respectively, and the average particle size is 9 μm.
Alumina cement, Bayer alumina with 99.6 wt% Al ₂ O ₃ purity and 4.3 μm average particle size and fumed silica with 93 wt% SiO ₂ purity and 0.8 μm average particle size Was. In addition, powders of sodium tetrapolyphosphate having a content of P ₂ O ₅ and Na ₂ O of 60.4% by weight and 39.7% by weight, respectively, were used as dispersants.

The refractory aggregate, the refractory powder and the dispersant were prepared, and the amount of water shown in Table 1 was added to each composition (the refractory aggregate and the refractory powder were the inner weight%, and the others were outside weight%). Hanging weight%)
And add 3 in a 500 kg vortex mixer.
The mixture was kneaded for a minute to obtain kneaded clay. The fluidity of each kneaded material is as follows. Each kneaded kneaded material is poured into a cone shape having a top end inner diameter of 50 mm, a lower end inner diameter of 100 mm, a height of 150 mm, and a truncated conical cone having upper and lower ends opened. The spread diameter when the sample was pulled out and allowed to stand for 60 seconds was measured in two directions, and the average value was defined as the flow value.

The quick-setting agent is a powder having a particle size of 800 μm or less and an average particle size of about 150 μm, and comprises sodium aluminate (containing about 20% water of crystallization) and sodium carbonate:
Using the material containing at a weight ratio of 1, the kneaded clay of the formulation shown in Table 1 was adjusted, and the spraying construction device having the configuration shown in FIG.
Dense spraying was performed on the refractory furnace structure having the configuration shown in FIG. That is, the heat insulating layer 17 is made of 28% and 44% of the average chemical components of Al ₂ O ₃ and SiO ₂ , and has a bulk specific gravity of 0.32, 1
The wet spraying was performed to a thickness of 150 mm with a lightweight spraying material having a thermal conductivity of 00 ° C and 0.06 kcal / mh ° C. Next, the furnace inner layer (second layer) 18 was replaced with the amorphous refractory composition of Example 3 and the wetted part furnace inner layer (first layer) 19 was replaced with the amorphous refractory composition of Example 1 and the non-wetted part furnace inner layer (first layer). The first layer) 20 was made of the amorphous refractory composition of Example 2 and each had a thickness of 200 m.
m, 250 mm, and 250 mm. These constructions were performed in a temperature range of 20 to 25 ° C.

In FIG. 4, reference numeral 31 denotes a pressure feed pump;
a and 32b are pressure feed pipes, 33 is a nozzle pipe, 34 is a spray nozzle 35 is a quick binder feeder, 36 is an air compressor, 37 is a mixer, 38 is a heat insulating wall, 3
9 is a sprayed construction body, 40 is a compressed air inlet,
Reference numeral 41 denotes a quick-setting agent inlet, and reference numerals 42 and 43 denote valves for adjusting the air flow rate. In addition, two pistons are provided as a pressure feed pump.
Using a pressure pump BSA702 manufactured by Putzmister, the pumping speed was adjusted to 3 tons per hour with kneaded clay, and 4
Compressed air adjusted to ６6 atm was injected to supply the clay to the spray nozzle.

In order to quantitatively supply the powdery quick setting agent to the kneaded material, a Q gun manufactured by Nippon Pribrico Co., Ltd. having a table feeder was used, and the air pressure was controlled within a range of 3 to 4 atm. Was adjusted to the injection amount of the quick setting agent shown in FIG.

In the spraying apparatus used in the above embodiment, the pressure-feeding pipe 32a from the pressure-feed pump 31 to the compressed air inlet 40 was narrowed down to a steel pipe having a size of 65A and a length of 70m and a length of 65 to 50A. It is assumed that a tapered steel pipe having a length of 1 m is connected, and a pressure-feeding pipe 32b from the compressed air injection port 40 to the quick-setting agent injection port 41 has a length of 3 and a size of 50A.
m, and the nozzle pipe 33 from the quick-setting agent injection port 41 to the spray nozzle 34 has a length of 1.50A and a length of 1.
A 2 m rubber hose was connected so that there was no step inside the pipe. Further, a Y-shaped tube was attached to each of the compressed air injection port 40 and the quick setting agent injection port 41.

Since the spray nozzle 34 is connected to a flexible rubber hose, it is easy to move and change the direction within the range of the rubber hose. Installed. According to this construction method, there was no need to attach and remove the formwork required for conventional vibration construction, and the refractory furnace structure could be constructed in a very short time. Furthermore, there was almost no dust generation during spraying, and the working environment was extremely good as compared with the conventional dry spraying method for irregular shaped refractories.

Next, approximately 500 mm × 50 from each sprayed layer
Cut out a construction body of 0 mm x 200 mm,
After drying for 4 hours, a test piece of 40 mm × 40 mm × 80 mm was cut out, and apparent porosity, bulk specific gravity, and compressive strength were measured by a method specified in JIS-R2205.

Examples 1, 2 and 3 in Table 1 respectively constitute the refractory furnace structure of the present invention, the inner layer (first layer), the inner layer (first layer) and the furnace Although the composition forms the inner layer (second layer), the physical properties such as bulk specific gravity and compressive strength of the construction body are extremely high and dense.

The spraying construction device shown in FIG. 5 is an example of another construction device which can be used for performing spraying construction.
31 is a pressure feed pump, 32a is a pressure feed pipe, 33 is a nozzle pipe, 34 is a spray nozzle, 35 is a quick binder feeder,
36 is an air compressor, 37 is a mixer, 38 is a construction wall surface, 39 is a sprayed construction body, 44 is an inlet for compressed air and quick-setting agent, and 42 and 43 are valves for adjusting the air flow rate. In this case, the quick-setting agent injection port and the compressed air injection port are located at the same position, and the pressure feed pipe 32a and the nozzle pipe 3
3 and the air flow control valve 42 is fully opened and 43 is fully closed, it is possible to perform spraying using only the air for transferring the quick-setting agent. Excellent effects are obtained, such as easy operation of the apparatus, reduction in the amount of air used for spraying the clay, and reduction in the amount of dust generated.

[0069]

[Table 1]

[0070]

As described above, according to the method for forming a refractory furnace structure having a porous heat-insulating layer of the present invention, there is no need to attach or remove the formwork required in the conventional vibration construction, and it is extremely short-term. A refractory furnace structure could be constructed in the meantime, and there was almost no dust generation during spraying, and the working environment was extremely good as compared with the conventional method of dry-blasting amorphous refractories.

Further, the refractory furnace structure having the heat insulating layer obtained by the spraying method of the present invention has extremely high physical properties and strength, and has an aluminum melting furnace,
Demonstrates sufficient physical properties to be applied to various melting metal melting furnaces and holding furnaces such as holding furnaces, copper melting furnaces, steelmaking ladles, degassing furnaces, heating furnaces, and the industrial value is enormous. .

[Brief description of the drawings]

FIG. 1 is an explanatory longitudinal sectional view showing a typical example of a furnace structure formed by the present invention.

FIG. 2 is an explanatory longitudinal sectional view showing another typical example of the furnace structure formed by the present invention.

FIG. 3 is an explanatory longitudinal sectional view showing another typical example of the furnace structure formed by the present invention.

FIG. 4 is a schematic diagram of an example of an apparatus used to form the furnace structure of the present invention.

FIG. 5 is a schematic diagram of another apparatus used to form the furnace structure of the present invention.

FIG. 6 is an explanatory longitudinal sectional view showing a typical example of a conventional furnace structure.

[Explanation of symbols]

 1, 11: hearth section 2, 12: side wall section 3, 13: ceiling section 14, 17, 23: heat insulating layer 15, 16, 18, 19, 24: spray layer on furnace inner surface 31: pumping pump 32a, 32b : Pressurized piping 33: Nozzle piping 34: Spray nozzle 35: Quick binder feeder 40: Compressed air inlet 41: Quick binder inlet

Claims (4)

[Claims] 1. A self-fluidizing material comprising a refractory heat-insulating layer provided on the outside of a furnace, and an internal refractory composition containing a refractory aggregate, a refractory powder and a dispersing agent, to which water is added and kneaded. Is pumped to the construction site by a pressure pump and a pressure pipe, and compressed air and a required amount of quick-setting agent are respectively supplied from a compressed air inlet and a quick-setting agent inlet provided at a downstream portion of the pressure pipe. Injected into the soil, the kneaded clay mixed with the quick-setting agent together with the injected compressed air is sent to the spray nozzle connected to the tip by nozzle piping, and the kneaded clay is sprayed from the spray nozzle to the construction location, thereby insulating A method for forming a refractory furnace structure, comprising forming a dense spray layer on a lining of a layer. 2. The method for forming a refractory furnace structure according to claim 1, wherein the quick-setting agent inlet is provided downstream of the compressed air inlet or at the same position as the compressed air inlet. 3. The method for forming a refractory furnace structure according to claim 1, wherein the quick-setting agent is injected using part or all of the compressed air injected into the clay. 4. A clay having self-fluidity having an upper end inner diameter of 50%.
mm, the inner diameter of the lower end is 100 mm, the height of 150 mm, and the cone immediately after kneading is filled and filled into a truncated cone-shaped cone having upper and lower ends opened, the cone is pulled out upward, and the spreading diameter when left to stand for 60 seconds is 180 mm. The method for forming a refractory furnace structure according to any one of claims 1 to 3, which exhibits the above fluidity.