JPH1112049A - Coarse grain-containing amorphous refractory for wet spray application - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the amorphous refractory not causing the rebound loss of grains, even when the coarse grains having grain diameters of >=10 mm are added, in a wet spray application, and having the same spalling resistance as that of an amorphous refractory for a casting application. SOLUTION: This amorphous refractory for wet spray application is obtained by forcibly feeding an amorphous refractory material preliminarily kneaded with water into a transport pipe, adding compressed air and a coagulant to the amorphous refractory material from the same route or another route, and subsequently spraying the mixture on a target to be applied from a spray nozzle. Therein, 10-50 outer wt.% of one or more kinds of coarse grains having grain diameters of 10-40 mm and selected from coarse electrically fused or sintered refractory materials, ground brick grains, and the ground grains of waste bricks or waste amorphous refractories, and a coagulation-initiating time after the addition of the coagulant is controlled within 1 min.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an irregular shaped refractory for wet spraying containing large grains suitable for wet spraying used in molten metal containers, molten metal processing equipment, cement kilns, incinerators and the like.

[0002]

2. Description of the Related Art Conventionally, wet sprayed amorphous refractories have been used for the construction or repair of initials of amorphous refractories used in molten metal containers, molten metal processing equipment, cement kilns, incinerators and the like. ing. For example, JP
Japanese Patent Application Laid-Open No. 4-61005 discloses an alumina castable wet spraying method in which an amorphous material kneaded with water is sent to a spray nozzle and a coagulant is added in the spray nozzle. . Further, in order to enhance the spalling resistance of castable materials, for example, Japanese Patent Application Laid-Open No.
No. 26979 discloses an example in which coarse particles having a particle size of 50 to 90 mm are added in an amount of 15 to 50% by weight.
No. 8 discloses an example in which coarse particles having a particle size of 10 to 100 mm are added by 5 to 60% by weight in an outer case.

[0003]

The wet spraying method is an efficient method for applying irregular shaped refractories without requiring any manpower or cost such as installation and removal of a formwork. Due to the method of obtaining a construction body by that, that is, in order to give a large kinetic energy to the amorphous refractory and spray it, the coarse particles of large mass contained in the amorphous refractory material collided with the workpiece There is a disadvantage that the rebound is rebounded and falls down as rebound dross, so that the adhesion rate is reduced. Therefore, the amorphous refractories for wet spraying are generally limited in the maximum particle size of the raw material to less than 10 mm, and have a lower spalling resistance than the irregular refractories for casting containing coarse particles. It was inferior.

[0004] In addition, for the purpose of reducing the material cost, crushed granules of brick or irregular refractories are added to irregular refractories for casting or the like. For fixed refractories, the addition of crushed particles of coarse waste materials has not been put to practical use for the same reason.

According to the present invention, in order to solve the above-mentioned problems, in wet spraying, even if coarse particles having a particle diameter of 10 mm or more are added, rebound loss is extremely small, and irregular shapes for pouring are used. An object is to enable the same spalling resistance as that of a refractory.

[0006]

According to the present invention, an amorphous refractory material preliminarily kneaded with water is pumped in a transport pipe by a pump, and after the pumping, compressed air and a coagulant are added from the same path or another path. Amorphous refractories for wet spraying, which are sprayed from a spray nozzle onto a workpiece, are used for forming a refractory material such as an electrofused or sintered coarse refractory material having a particle size of 10 to 40 mm, a crushed brick, a brick or an irregular refractory material. One or more coarse particles composed of crushed particles, which are waste materials of fixed refractories, are externally added in an amount of 10 to 50% by weight and the coagulation starting time after the addition of the coagulant is set to within 1 minute. .

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION The amorphous refractory for wet spraying according to the present invention comprises a refractory aggregate and fine powder, a binder, a flow aid, a deflocculant and the like, which are irregular refractory materials. The required amount of water is added to the mixture, and the mixture is kneaded with a mixer. The kneaded irregular-shaped refractory material is pumped through a transport pipe such as a pipe or a hose to the spray nozzle, and after the pumping, compressed air and a coagulant are added. Then, it is constructed by spraying the object to be constructed from a spray nozzle. As the pumping means, a pump such as a piston pump or a squeeze pump or an air pumping device such as a lead gun can be used. The kneading and pumping steps can also be performed by separate devices, locations, or continuous devices.

[0008] The refractory aggregate and fine powder constituting the amorphous refractory material may be any suitable refractory material such as a molten metal container, a molten metal processing apparatus, a cement kiln, an incinerator and the like. For example, electrofused or sintered alumina,
Calcined alumina, bauxite, electrofused or synthetic mullite,
Sillimanite, andalusite, kyanite, ban shale, chamotte, rock, clay, silica, fused silica, electrofused or sintered magnesia, electrofused or sintered spinel,
Fused or sintered zirconia, zircon, chromite, fused or sintered magnesia-lime, fused zirconia-mullite, fused alumina-zirconia, titania, silicon carbide,
Examples include silicon nitride, natural or artificial graphite, petroleum coke, pitch coke, anthracite, carbon black, amorphous carbon such as pitch, and the like, and one or more of these can be used. In the case of a castable composition containing a carbon component such as graphite or amorphous carbon, for the purpose of preventing carbon oxidation and improving strength, aluminum, aluminum-silicon alloy, aluminum-magnesium alloy, metal powder such as silicon or magnesium, It is also possible to use a carbide such as silicon carbide or boron carbide, a boride such as zirconium boride, or a glass component such as borosilicate glass. The fine powder referred to in the present invention refers to a powder having a particle size of 0.2 mm or less, of which substantially 50% by weight or more is 74 μm or less.

[0009] The coarse particles may be selected from the group consisting of electrofused or sintered coarse refractory materials, brick crushed particles, and crushed particles of brick or irregular refractory waste materials having a particle size of 10 to 40 mm.
The seed or two or more kinds are externally added in the range of 10 to 50% by weight. The particle size is 40mm or less, and the additive amount is 50
The reason for limiting the amount to be not more than the weight% is that if the particle size and the addition amount exceed the above, the pumping property at the time of construction is reduced and the adhesion rate is reduced. In order to improve the pumping performance of the pump, the maximum particle size is preferably 3/5 or less of the minimum inner diameter of the cylinder diameter or pipe inner diameter of the pump or the inner diameter of the pumping pipe. Particle size is 10m
The reason why the addition amount is limited to 10% by weight or more when the particle size is m or more is that when the particle size and the addition amount are smaller than these, the effect of improving spalling resistance, which is the purpose of adding coarse particles, cannot be obtained. Because. In the case of using crushed granules of bricks or crushed granules of bricks or irregular refractory waste materials, the crushed granules may be coated or impregnated with silica sol or an organic substance to reduce the water content. In addition, among the crushed granules of bricks, and the crushed granules of waste materials of bricks or irregular refractories, those having a maximum particle size of less than 10 mm may also be used as part of the refractory aggregate in the irregular refractory materials. Of course it is possible.

[0010] The coagulant added later acts to eliminate the effect of the deflocculant in the amorphous refractory material previously kneaded with water and immediately convert it to a viscous plastic, and at the same time, cure the binder. And impart sufficient adhesiveness and rigidity to the construction body. That is, the coagulant causes the amorphous refractory material kneaded with water to coagulate and promotes the hardening due to the formation of the joint by the binder. Examples of the coagulant having such an action include aluminates such as sodium aluminate, carbonates such as sodium carbonate, alkali silicates such as sodium silicate, chlorides such as calcium chloride, sodium hydroxide and calcium hydroxide. There are aqueous solution, suspension or powder of hydroxide, calcium aluminate, Portland cement, etc.
Species or two or more species can be used.

As the peptizer, any of those commonly used for amorphous refractories can be used for the present invention. For example, one or more of condensed phosphoric acid, polyacrylic acid, polycarboxylic acid, phosphonic acid, humic acid, alkylsulfonic acid, aromatic sulfonic acid and the like or salts thereof are used.

The types, concentrations and amounts of the deflocculants and flocculants are determined by the method described in “JIS R 2521 Physical Test Method for Alumina Cement for Refractories, 8” by using a sprayable amorphous refractory material which has been previously kneaded with water. The setting time is adjusted so that the setting start time after adding the flocculant measured according to the “setting test” is within 1 minute, preferably within 0.5 minute. If the initial setting time is longer than that, the adhesion rate during spraying construction decreases. In the measurement of the initial setting time according to “JIS R2521 Physical Test Method for Alumina Cement for Refractories 8. Setting Test”, the setting initial setting time within 5 seconds cannot be measured no matter how quickly. Therefore, it is not possible to clearly define the lower limit of the setting start time.However, in the case of wet spraying, if the setting start time is extremely short, there is a problem that rebound loss increases. Since the time required for spraying the construction body is about one second, this is considered to be the lower limit that can define the setting start time.

As the binder, use is made of one or more of cement such as alumina cement, magnesia-silica hydraulic composition, hydraulic transition alumina, alkali silicate, phosphate, clay, colloid particles and the like. can do.

As the fluidity aid, calcined alumina, siliceous fine particles, titania, carbon black and the like have a particle size of 10 μm.
One or more kinds of ultrafine powder or ultrafine particles having a particle size of m or less can be used. Here, as the siliceous fine particles, one or two or more of those called evaporated (volatile) silica which is generated as a by-product during the production of silicon or ferrosilicon, white carbon, anhydrous or hydrous amorphous silicic acid, shirasu and silica sol Use

[0015]

EXAMPLES Examples and comparative examples of the present invention are shown in Table 1.

For the application of the examples and comparative examples defined in the present invention, crushed alumina bricks which were dried after impregnation with silica sol were used as coarse particles. Also, sintered alumina having a purity of 99.7 wt% and ball clay are used as the refractory aggregate and fine powder, and "High alumina cement Hi" manufactured by Denki Kagaku Kogyo, which is an alumina cement, is used as a binder. 99.6wt% purity as auxiliary
Calcined alumina with an average particle size of 1.5 μm and purity of 96.0 wt
% Evaporating silica having an average particle size of 0.28 μm, sodium acrylate as a deflocculant, 9.2% by weight of K ₂ O, 20.5% by weight of an aqueous solution of potassium silicate of SiO ₂ as a flocculant. A 40% by weight CaCl ₂ aqueous solution of calcium chloride was used. Here, all the average particle diameters of the fine powder are values measured by a laser diffraction method. It should be noted that the present invention is not limited to the examples shown here, and the same effects can be obtained as long as they are described in the embodiments of the present invention.

In the table, the amounts of the coarse particles, water (for kneading) and the aggregating agent are indicated by (+) because the weight is 100% by weight. The addition amount of the flocculant is indicated by the addition amount as an aqueous solution.

In the spraying operation, the first component shown in the table is kneaded with a mixer, and the mixture is mixed with Allentown.
7.6c inside diameter using AP-10 swing valve pump
m (3 inches) through a heavy-duty hose of 7.62 m (25 ft) long, and at the spray nozzle connected to the tip, 5.52 kg / cm ² (8
0 psi), 8.5 m ³ / min (300 cfm) of compressed air is added together with the flocculant (second component), and the vertically placed chamotte brick with an area of about 9.3 m ² (about 100 ft ² ) is applied to the surface. The spraying method was used. Here, the transfer of the flocculant is performed at 35.15 kg / cm ² (500 ps
i) A diaphragm chemical pump was used.

The items of "setting start time" shown in the table are as follows:
By using the construction body constructed under the above conditions, "JIS R
Physical test method of 2521 alumina cement for refractories When the setting start time within 0.5 minutes from the time of application (that is, from the time when the coagulant was added) measured according to the “setting test”, the mark “◎”, 1 Those that were less than one minute are marked with a “〇”, and those that were longer than one minute are marked with a “x”.

The item of "adhesion" shown in the table is marked with "◎" if the ratio of the adhesion weight to the total construction weight was very good at 95% or more under the above-mentioned conditions. , 90% or more and less than 95% are marked with “〇”, and those with less than 90% are marked with “X”.

The items of "spalling resistance" shown in the table are as follows. After drying under the above-mentioned conditions so that the surface of the chamotte brick has a heating surface of 460 mm square and a thickness of about 150 mm, the brick is sufficiently dried. After using the test material and heating the surface of the test material to 1400 ° C. and holding for 3 hours, 3
After air-cooling for 0 minutes, the process of [heating for 30 minutes in a furnace holding the heating surface at 1400 ° C. → air cooling for 30 minutes] is repeated up to 20 times until a crack is generated. The symbol "◎" indicates that no crack was generated, and the symbol "〇" indicates that the number of repetitions until crack generation was 10 or more and less than 20 was "X" if the crack occurred less than 10 times. Is filled in.

[0022]

[Table 1] Examples 1 to 4 shown in Table 1 are the results of the construction bodies satisfying the conditions specified by the present invention, and it was possible to obtain construction bodies having good adhesion and spalling resistance. Table 1 shows Comparative Examples 1 to 7.

Comparative Examples 1 and 2 are examples in which no coarse particles are added. In Comparative Example 1, the spraying workability such as the pumping property and the adhesion rate was very good, but the spalling resistance was inferior to the examples of the present invention. In Comparative Example 2, the aggregation starting time exceeded 1 minute of the present invention, but the adhesion rate was good because no coarse particles were added, but the spalling resistance was inferior to the present invention.

Comparative Example 3 was an example in which the amount of coarse particles added was larger than the specified range (10 to 50% by weight) of the present invention, and could not be pumped.

Comparative Example 4 is an example in which the maximum particle size of the coarse particles is larger than the specified range (10 to 40 mm) of the present invention, and the adhesion rate was not satisfactory.

Comparative Example 5 is an example in which the size range of the coarse particles is smaller than the specified range (10 to 40 mm) of the present invention, and the improvement in spalling resistance was not satisfactory.

Comparative Examples 6 and 7 are examples in which the setting start time does not satisfy the condition specified by the present invention, and the adhesion rate was not satisfactory.

[0028]

According to the present invention, the rebound loss can be reduced even when coarse particles having a particle size of 10 mm or more are added in wet spraying, and the coarse particles are used similarly to the irregular refractories for pouring. The spalling resistance has been greatly improved. In addition, since it is possible to use crushed particles of brick or amorphous waste material, it can contribute to environmental conservation, resource saving, cost reduction by using recycled materials, and the like.

Claims (1)

[Claims] 1. An amorphous refractory material previously kneaded with water is pumped through a transport pipe by a pump, and after the compressed air, compressed air and a coagulant are added from the same path or another path. Amorphous refractories for spraying wet-type spraying, in which the refractory material is electrofused or sintered coarse refractory material with a particle size of 10 to 40 mm, crushed bricks, bricks, or crushed waste of irregular refractories One or two or more coarse grains consisting of grains are externally applied in an amount of 10 to 50% by weight.
Amorphous refractory for wet spraying, containing coarse particles, in which the start of coagulation after the addition of a coagulant and the addition of a coagulant are within 1 minute.