JP2972179B1 - Amorphous refractory composition for wet spraying - Google Patents

Abstract

An object of the present invention is to provide an amorphous refractory composition for wet spraying having a durability equal to or higher than that of a castable. SOLUTION: The amorphous refractory composition for wet spraying of the present invention is obtained by kneading a predetermined amount of water to an irregular refractory composition containing at least a refractory raw material whose particle size has been adjusted to coarse particles to ultrafine powder. The obtained kneaded material is pressure-fed to a spray nozzle by a pressure feeder,
In the spray nozzle, an alkaline gelling agent is added and compressed with compressed air, and after mixing, the amorphous refractory composition for use in wet spraying comprising spraying, wherein the amorphous refractory composition contains alumina. 5 to 15% by weight of an alumina cement having an amount of 70% by weight or more, 3 to 15% by weight of a magnesia raw material having a particle size of 1.0 mm or less, 66 to 92% by weight of an alumina raw material and / or a spinel raw material, and mainly silica. Characterized by containing 0.2 to 4% by weight of ultrafine powder.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an amorphous refractory composition for wet spraying used as a refractory for furnace lining.

[0002]

2. Description of the Related Art In recent years, blast furnace gutters, hot metal pots, mixed iron wheels, VOD
Dense castables are used as refractory for furnace linings such as molten steel ladle, RH vacuum degassing furnace, tundish, various furnace lids, incinerators and preheaters for cement, including pots, and high durability is obtained. Have been. However, the construction of castables requires the work of setting and pouring a frame at the construction site, and it is still simpler than brick construction in terms of labor saving, but still has the complexity. On the other hand, the spraying construction method does not require a frame for construction and can be locally repaired, so that it is a significantly advantageous construction method from the viewpoint of labor saving. The spraying method includes a dry spraying method, a semi-dry spraying method and a wet spraying method, and a wet spraying method with almost no dust has attracted attention for the purpose of preventing the work environment from being deteriorated due to dust generation. No. 7350 describes the spraying system.

[0003] That is, in Japanese Patent Publication No. 57-7350, a slurry-like amorphous refractory is pumped by a transport pipe by a transporter, and is hardened together with compressed air by a converging nozzle provided at the tip of the transport pipe. Disclosed is a method for spraying an amorphous refractory, characterized by adding and spraying an accelerator.

Japanese Patent Laid-Open Publication No. 9-25175 discloses a self-fluidity obtained by adding water to a refractory aggregate powder, a refractory powder composition containing a refractory powder and a small amount of a dispersant, and kneading the mixture. The kneaded clay having the pressure is pumped to the construction site by the pump and the piping, and the compressed air and the required amount of the quick-setting agent are respectively supplied 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-feeding pipe. Injecting, sending the kneaded clay together with compressed air to the spray nozzle connected to the tip of the nozzle with a nozzle pipe, and spraying the kneaded clay from the spray nozzle to the construction site It has been disclosed.

Further, Japanese Patent Application Laid-Open No. 9-26267 discloses a self-fluidity obtained by adding water and kneading water to an amorphous refractory powder composition containing a refractory aggregate, a refractory powder and a small amount of a dispersant. The kneaded material having the kneaded material is pumped to the construction site by a pressure pump and a pressure piping, and compressed air and a predetermined amount of quick-setting agent are respectively supplied from the compressed air injection port and the quick-setting agent injection port provided in the downstream portion of the pressure-feed pipe in the kneaded material The kneaded material in which the quick-setting agent is mixed together with the injected compressed air is sent to a spray nozzle connected to the tip of the kneaded material through a nozzle pipe, and the kneaded material is sprayed from the spray nozzle to a construction site. A method for spraying a fixed refractory is disclosed.

[0006] Japanese Patent Application Laid-Open No. 9-241080 discloses a kneaded pump capable of containing a castable solid content and mainly comprising a refractory aggregate, calcium aluminate cement, a flow aid, a deflocculant, and water. A first component, wherein the water is present in an amount sufficient to achieve a pumpable consistency of the kneaded first component; and at least about 1.
Substantially non-slump, high density, low moisture, low content consisting of a flocculant as a second component to be added to the first component during application in an amount sufficient to provide a dry bulk density of 92 g / cm ³ A cement castable composition is disclosed.

Further, Japanese Patent Application Laid-Open No. 9-250880 discloses that a kneaded product of an amorphous refractory powder and a solvent is pumped to a nozzle, a hardening accelerator is mixed with the kneaded material in the nozzle, and Disclosed is a method for spraying irregular-shaped refractories, which is sprayed on a construction surface with compressed air.

Japanese Unexamined Patent Publication No. Hei 9-315872 discloses that 67 to 97.5% by weight of a refractory aggregate having a particle size of 10 mm or less, 2 to 25% by weight of a refractory ultrafine powder having a particle size of 10 μm or less, Refractory composition 1 comprising 0.5 to 8% by weight of cement
A low-cement castable, characterized in that 0.01 to 1.0% by weight of a dispersing agent is externally added to 00% by weight, is kneaded with water in advance with a mixer to make the workability. It is transported to the spray nozzle by a pressure pump, and the compressed air is mixed with the compressed air at the spray nozzle [SiO ₂ / R ₂ O molar ratio is 2.0 to 3.3 (R ₂ O is an alkali metal oxide). , A specific gravity of not less than 40 in terms of Be (degree of Baume) at 15 ° C.] as a shape-retaining agent.
A wet spraying method characterized by adding 5% by weight and spraying is disclosed.

[0009]

However, the construction method and the composition described above are not limited to the construction method in which the castable is pumped and sprayed using a well-known pump.
It is a material for self-flow castable, low-cement castable or pressure-blasting construction method using castable with added plasticizer, and although the quality similar to castable is obtained, the construction body with construction thickness of 30 mm or more is used. When building, problems such as peeling occur,
At present, it is still difficult to say that the durability is equivalent to castable.

[0010] Accordingly, an object of the present invention is to provide an amorphous refractory composition for wet spraying having a durability equal to or higher than that of a castable.

[0011]

Means for Solving the Problems The present inventors made use of magnesia fine powder and alumina cement to make the structure of a sprayed body as dense as castables and for wet spraying with little structural change. As a result of intensive studies for developing an amorphous refractory composition, the present invention has been completed.

[0012]

[0013] Namely, the present invention is pumping a coarse-ultrafine a kneaded product obtained by kneading a predetermined amount of water to the plastic refractory composition that Do contain at least a refractory material which is particle size control In a non-uniform refractory composition for use in wet spraying comprising spraying, after feeding to a spray nozzle with a machine, adding an alkaline gelling agent with compressed air at the spray nozzle and mixing, The amorphous refractory composition contains 5 to 15% by weight of an alumina cement having an alumina content of 70% by weight or more,
3 to 15% by weight of a magnesia raw material having a particle size of 1.0 mm or less, and 66 to 9 of an alumina raw material and / or a spinel raw material.
2% by weight, and 0.2 to 4 ultrafine powder mainly composed of silica.
Relative to the formulation 100% by weight comprising a weight percent containing, acrylic acid, derivatives of carboxylic acids or phenolsulfonic acid or a water-soluble polymer compound as a main component thereof condensate or polymer or copolymer An object of the present invention is to provide an amorphous refractory composition for wet spraying, characterized in that one or two or more kinds thereof are contained in an outer amount of 0.01 to 0.5% by weight.

[0014]

DETAILED DESCRIPTION OF THE INVENTION The alumina cement which can be used in the amorphous refractory composition for wet spraying of the present invention is a calcium aluminate having an alumina content of 70% by weight or more and a lime (CaO) content of less than 30% by weight. Is a generally commercially available alumina cement having as a main mineral. Alumina cement containing corundum can also be used. The amount of alumina cement is in the range of 5 to 15% by weight, preferably 6 to 10% by weight. When the blending amount of alumina cement is less than 5% by weight, the strength of the construction body after spraying is low, and the structural strength in a low temperature range of 1000 ° C. or less cannot be sufficiently obtained. This is not preferable because peeling damage may occur due to the gap in the structure of the construction body. The amount of alumina cement is 1
If it exceeds 5% by weight, the lime component in the composition becomes too large, and the corrosion resistance is undesirably reduced.

The magnesia raw material that can be used in the amorphous refractory composition for wet spraying of the present invention is not particularly limited. For example, naturally occurring magnesite, its calcined product, or seawater magnesia obtained from seawater. Alternatively, one or a mixture of two or more types of electrofused magnesia obtained by electrofusing. Fine particles and ultrafine powder having a particle size of 1.0 mm or less can be used as the particle size of the magnesia raw material, and ultrafine powder of 0.3 mm or less is more preferable. Magnesia raw material particle size is 1.0
If the diameter exceeds mm, the generation of spinel becomes slow and small due to the reaction between magnesia and alumina, and it is not preferable because the bonding strength due to the reaction and the densification of the structure due to the diffusion of the reactant cannot be achieved. The amount of the magnesia raw material should be 3 ~
It is in the range of 15% by weight, preferably 5-12% by weight. When the amount of the magnesia raw material is less than 3% by weight, the amount of spinel produced is small due to the reaction between magnesia and alumina, the bonding strength due to the reaction and the densification of the structure due to the diffusion of the reactant cannot be achieved, and peeling damage is caused. It is not preferable because it induces or lowers corrosion resistance. On the other hand, when the amount of the magnesia raw material exceeds 15% by weight, spinel and magnesia produced by the reaction of magnesia and alumina coexist, and particularly, the vessel lining which comes into contact with molten steel such as a molten steel ladle or a hot tundish. In the case of using the slag, the penetration of the treated slag is not suppressed, so-called structural spalling occurs, and the durability is unfavorably reduced.

As a main raw material used in the amorphous refractory composition for wet spraying of the present invention, an alumina raw material and / or a spinel raw material can be used. As the alumina raw material, for example, sintered alumina, electrofused alumina, bauxite, ban shale, mullite, and bricks (including post-use products) composed of these alumina raw materials can be used. Can be used in combination. As the spinel material, use is made of alumina-magnesia spinel having an alumina content of 70% by weight or more, sintered spinel, electrofused spinel, or a crushed product of alloy slag mainly composed of spinel mineral generated as a by-product during alloy refining. And these can be used in combination. The alumina raw material and / or
Alternatively, the amount of the spinel material is in the range of 66 to 92% by weight.

Further, in the amorphous refractory composition for wet spraying of the present invention, in order to improve cohesiveness during wet spraying and maintain high adhesiveness, ultrafine powder mainly composed of silica is added in an amount of 0.2.
To 4% by weight, preferably 0.5 to 2% by weight. This ultrafine powder is generally called silica flour or silica fume and has a silica content of 90% by weight or more, and may contain a small amount of zircon or zirconia. 0.2% by weight of ultrafine powder mainly composed of silica
If the amount is smaller, the sprayed material after spraying flows out from the sprayed surface and the adhesion rate is lowered, and at the same time, it becomes difficult to construct a sprayed construction having a construction thickness of 30 mm or more. On the other hand, if the amount of the ultrafine powder mainly composed of silica exceeds 4% by weight, the viscosity of the kneaded material is high, the pumping property is impaired, and it is difficult to construct a uniform sprayed construction, which is not preferable.
By adding an ultrafine powder mainly composed of silica to the wet-type amorphous refractory composition for wet spraying of the present invention, the composition is kneaded with water and then pumped by a pump, and a nozzle for spraying the alkaline gelling agent described below. When mixed with compressed air, the reactivity with the alkaline gelling agent can be increased.

Further, for the same purpose as the effect of the ultrafine powder mainly composed of silica, a water-soluble polymer mainly composed of a derivative of acrylic acid, carboxylic acid or phenolsulfonic acid or a condensate, polymer or copolymer thereof is mainly used. Molecular compound 1
A composition 10 comprising one or more of the above-mentioned alumina cement, magnesia raw material, alumina raw material and / or spinel raw material, and ultrafine powder mainly composed of silica.
0.01% to 0.5% by weight based on 0% by weight
I do . Examples of the water-soluble polymer compound include one or two of alkali or alkaline earth metal salts such as sodium polyacrylate, calcium polycarboxylate, sodium bisphenolsulfonate, and condensates, polymers, and copolymers thereof. The above can be used. When the blending amount of the water-soluble polymer compound is less than 0.01% by weight, the sprayed body flows out from the sprayed surface after spraying to lower the adhesion rate, and at the same time, constructs a sprayed body having a work thickness of 30 mm or more. It becomes difficult. Also, if the amount exceeds 0.5% by weight,
There is no problem in the construction itself, but the price of refractory rises,
It is hard to be a commercial base.

The amorphous refractory composition for wet spraying of the present invention may contain, if necessary, a dispersing agent such as aluminum powder, aluminum alloy powder, foaming agent, metal fiber, organic fiber, ceramic fiber, and condensed phosphate. May be added in a range that does not impair the effects of the present invention.

Various alkaline substances can be used as the alkaline gelling agent to be added by compressed air to the amorphous refractory composition for wet spraying of the present invention at the spray nozzle. For example, sodium silicate, potassium silicate, sulfate, lithium silicate,
Powders such as lithium carbonate and potassium hydroxide or aqueous solutions thereof can be used, but sodium silicate or potassium silicate solutions which are widely marketed, easily available, and have good dispersibility are desirable. The amount of the alkaline gelling agent to be added is desirably 0.1 to 3.0% by weight (as a solid content) based on the pressure-feed material after kneading. Here, the addition amount is 0.
If the amount is less than 1% by weight, the adhesion at the time of spraying is unpreferably reduced. If the amount exceeds 3.0% by weight, agglomeration starts in the spraying nozzle and the workability decreases. Not preferred.

In the spraying, water is added to the amorphous refractory composition for wet spraying of the present invention in an amount of 4 to 8% by weight (outer hook) and kneaded, and a pumping device such as a piston pump, a squeeze pump or a screw pump is used. The inside of the pipe is pressure-fed and mixed with the alkaline gelling agent fed by compressed air at a spray nozzle attached to the tip of the pipe and sprayed.

The spraying can be carried out directly on the steel shell of the can body, or can be carried out on an insulating brick which is constructed as a permanent upholstery, an insulating board, a refractory brick or a spraying material or a casting material. It can also be used for cold repair after using bricks, sprayed materials, and cast materials, or as a hot repair material during use.

[0023]

The present invention will be further described with reference to the following examples. Example 1 Table 1 shows the mixing ratios and test results of the amorphous refractory compositions for wet spraying of the present invention and comparative examples. After kneading each composition shown in Table 1 with a predetermined amount of water, it was sprayed by a wet spraying method using a commercially available piston type concrete pump.
A construction was obtained by drying at 5 ° C. for 24 hours. Thereafter, the construction body was cut into a shape of 40 mm × 40 mm × 110 mm to obtain a sample for each test. The test results are also shown in Table 1.

[0024]

[Table 1]

[0025]

[Table 2]

[0026]

[Table 3]

[0027]

[Table 4]

In Table 1, a sodium silicate solution having a concentration of 40% by weight was used. In addition, the adhesion rate is a value obtained by measuring the weight of the material adhered to the construction surface and expressing it as an index when the total weight of the material used for construction is set to 100. The bending strength is 105 ° C. according to JIS R2553.
It was measured for each sample after drying and after firing at 1500 ° C. Furthermore, the compressive strength was measured for each sample after drying at 105 ° C. and firing at 1500 ° C. according to JIS R2555. In the erosion test, a converter slag was used as an erosion agent, and a rotary erosion test was performed at 1700 ° C. for 4 hours to measure the erosion size and the slag penetration amount.

[0029]

According to the amorphous refractory composition for wet spraying of the present invention, the following effects can be obtained: (1) The adhesive ratio at the time of cold spraying is 95% or more, and the conventional dry or semi-dry spraying is performed. 85% of the material is added with ultrafine powder mainly composed of silica, or a derivative of acrylic acid, carboxylic acid or phenolsulfonic acid, or a water-soluble polymer compound mainly composed of a condensate, polymer or copolymer thereof. High adhesion compared to the 90% adhesion rate of no similar wet sprayed material; (2) Used in molten steel ladle steel baths, providing the same service life as conventional cast materials. For partial repair, compared to the conventional dry or semi-dry refractory amorphous refractory composition having less than half the service life of the cast material, the same durability as that of the replenished repair cast material can be obtained; (3) When used for an upper RH tank or a cement preheater, compared to conventional high alumina casting materials and basic casting materials, there is less splash adhesion and the durability is 1.3 times to 1.3 times. 5 times improvement.

──────────────────────────────────────────────────続 き Continued on front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C04B 35/66

Claims (1)

(57) [Claims] Spraying at 1. A coarse-ultrafine in grain size adjusted refractory material a kneaded product obtained by kneading a predetermined amount of water to at least Do that monolithic refractory composition containing a pumping device In a non-uniform refractory composition for use in wet spraying, which comprises applying an alkaline gelling agent with compressed air in compressed air, mixing and then spraying, the non-uniform refractory composition The material is 5 to 15% by weight of alumina cement having an alumina content of 70% by weight or more, and has a particle size of 1.0 to 1.0%.
mm The following magnesia feedstock 3-15 wt%, the alumina raw material and / or a spinel raw material 66-92 wt%, and silica made by a 0.2 to 4% by weight containing ultrafine mainly formulations 100 One or two or more of water-soluble polymer compounds having acrylic acid, carboxylic acid or phenolsulfonic acid derivatives or their condensates, polymers or copolymers as main components are externally added to the weight%. .
An amorphous refractory composition for wet spraying, comprising from 0.01 to 0.5% by weight.