JPH10287476A - Surface treatment of basic refractory raw material and production of basic prepared unshape refractories excellent in slaking resistance - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for the surface treatment of a basic refractory raw material capable of suppressing slaking reaction without causing the deterioration of its performance and a method for producing a basic prepared unshaped refractories. SOLUTION: The surface of a basic refractory raw material containing at least one selected from between MgO and CaO is coated with a silane coupling agent dissolved in an organic solvent and cured for 1 hr or more at a temperature of 30 deg.C or less, and then the treated basic refractory raw material is dried at a temperature of 100-200 deg.C for 1 hr or more to improve the slaking resistance of the basic refractory raw material. Further, to the surface-treated basic refractory raw material, a binder and a surfactant, whose amount is 0.2-5.0 by outer pts.wt. based on 100 pts.wt. of the kneaded material, are added and the mixture is kneaded after adding an appropriate amount of water. Thus, a basic prepared unshaped refractories, whose workability is retained, is obtained.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is to improve the digestion resistance of basic refractory raw materials used for maintaining the corrosion resistance of ladle exposed to molten steel, slag, etc., such as ladle and degassing, etc. The present invention relates to a method for surface treating a basic refractory raw material and a method for producing a basic amorphous refractory having excellent digestion resistance.

[0002]

2. Description of the Related Art Generally, refractories using basic refractory materials such as magnesia, magnesia-calcia, magnesia-dolomite, etc. are known to exhibit excellent corrosion resistance to high basicity slag and high FeO slag. ing.

[0003] In recent years, in order to save labor in furnace construction work, basic refractories have been made amorphous. Especially,
Among amorphous refractories, the technical progress of castable refractories used as wear refractories such as ladles is remarkable. In general, a castable refractory is constructed by mixing a predetermined amount of a refractory raw material, a binder such as alumina cement, and water, kneading the mixture with a mixer, and then pouring the mixture into a mold.
Thereafter, the binder is cured by a hydration reaction and the castable refractory is dried to obtain a refractory construction body having developed strength.

However, when the above-mentioned basic refractory raw material is used as an amorphous refractory raw material, particularly as a castable raw material, there is a problem that digestion is caused by high steam pressure during drying after construction. That is, MgO and CaO react with moisture in the air, and a digestion reaction for producing Mg (OH) ₂ and Ca (OH) ₂ proceeds, respectively. This digestion reaction is accompanied by a rapid volume expansion in the refractory tissue, and causes the deterioration of the structure such as loosening of bonds between particles and generation of cracks. Furthermore, if the digestion reaction is remarkable, the refractory may become unusable due to lack or collapse of the refractory.

[0005] Many inventions have been proposed to prevent the digestion reaction of basic refractory raw materials as described above. For example,
JP-A-7-215772 discloses a method of adding 0.1 to 20 parts by weight of amorphous kaolin fine powder to an amorphous refractory using a refractory raw material containing magnesia.

Also, the refractory journal, Vol. 48 (19)
96), No. 9, P474-481, magnesia raw materials used as raw materials for amorphous refractories, magnesia
As a method for preventing digestion of the lime raw material, a surface treatment method in which an organic solvent in which an organic silicon compound is dissolved is attached to the surface and dried at 150 ° C. is disclosed.

[0007]

However, Japanese Patent Application Laid-Open No.
According to the invention described in JP-A-215772, the amorphous kaolin cannot be uniformly dispersed in the refractory construction body,
The inability to prevent digestion due to direct contact between magnesia and water is not enough to prevent magnesia from being completely digested.

In the method described in the above-mentioned academic journal, it is difficult to coat the inside of the pores of the raw material with the organosilicon compound, and digestion may occur from an uncoated portion, and the effect is still unclear. In addition, since the surface of the raw material has a structure that repels water due to the hydrophobic group of the organosilicon compound, the fluidity at the time of construction is reduced, and the material may not be poured.

Accordingly, the present invention advantageously solves the above-mentioned problems, suppresses the digestion reaction without deteriorating the performance, and provides a surface treatment method for a basic refractory raw material and a base excellent in digestion resistance. It is an object of the present invention to provide a method for producing a refractory of irregular shape.

[0010]

Means for Solving the Problems In view of the above-mentioned problems of the prior art, the present inventors have made intensive studies and found that the basic refractory raw material and the binder were mixed before being kneaded with water. By treating the surface with a silane coupling agent, it is possible to suppress the digestion reaction of the basic refractory raw material, and as a method of suppressing a decrease in fluidity due to the surface treatment of the silane coupling agent, a surfactant is used during kneading. They have found that they can be added, and have completed the present invention.

That is, the gist of the present invention is as follows. (1) After coating the surface of a basic refractory raw material containing at least one kind of MgO and CaO with an organic solvent in which a silane coupling agent is dissolved, the composition is cured at 30 ° C. or less for 1 hour or more,
A surface treatment method for a basic refractory raw material, which is dried at 100 to 200 ° C for 1 hour or more.

(2) The surface is coated with an organic solvent in which a silane coupling agent is dissolved, then cured at 30 ° C. or less for 1 hour or more, and dried at 100-200 ° C. for 1 hour or more. To the basic refractory raw material containing one kind, a binder, and 0.2 to 5.0 parts by weight of a surfactant are externally added to 100 parts by weight of the kneaded material,
A method for producing a basic amorphous refractory having excellent digestion resistance, which is kneaded with an appropriate amount of water.

[0013]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. First, the invention according to claim 1 will be described. As the basic refractory raw material used in the present invention, electrofused magnesia,
Sintered magnesia clinker, dolomite, magnesia dolomite, electrofused magnesia-calcia, sintered calcia,
Electrofused calcia clinker or the like is used.

Next, a surface treatment is performed with a silane coupling agent for the purpose of preventing digestion of the basic refractory raw material. The silane coupling agent used in the present invention is an organic functional silane monomer, and is a general term for compounds having two types of reactive groups.
One of the reactive groups is called a hydrophilic group such as a methoxy group and an ethoxy group, and is hydrolyzed into silanol to form a chemical bond with a metal oxide as a refractory aggregate. The other reactive group is called a hydrophobic group such as an amino group, a vinyl group, an epoxy group, a mercapto group, or a chloro group, and forms a chemical bond with an organic substance such as an organic binder or a carbonaceous raw material.

That is, the silane coupling agent is a compound capable of chemically reacting with both a hydrophilic inorganic substance and a hydrophobic organic substance.

In the surface treatment of the basic refractory raw material of the present invention with the silane coupling agent, the hydrophilic group of the silane coupling agent forms a chemical bond with oxygen of the basic refractory raw material through a hydrolysis reaction and a dehydration condensation reaction. And coating the surface of the basic refractory raw material with a film of a silane coupling agent. By the surface treatment, the surface of the basic refractory raw material becomes hydrophobic, and becomes a state of being inactive with respect to the moisture absorbed from the air, the moisture generated by the condensation reaction during curing, and The contact with the basic refractory raw material can be cut off to suppress the digestion reaction of the basic refractory raw material.

Examples of the silane coupling agent used in the present invention include γ-glycidoxypropylmethoxysilane, γ-methacryloxypropyltrimethoxysilane, γ- (2-aminoethyl) aminopropyltrimethoxysilane, methyl Trimethoxysilane and the like,
There is no particular limitation.

The surface treatment of the basic refractory raw material with the silane coupling agent of the present invention includes a method of dipping the basic refractory raw material in a solution of the silane coupling agent or spraying the solution with a spray. There is no particular limitation.

After the basic refractory raw material is surface-treated with a silane coupling agent, it is cured. Here, the purpose of the curing in the present invention is to allow the silane coupling agent attached to the surface of the basic refractory raw material to penetrate into the raw material through the open pores present in the raw material, thereby allowing direct contact with water and steam. Is to prevent The curing time is preferably one hour or more, and if it is less than one hour, the silane coupling agent does not sufficiently penetrate into the inside of the raw material, so that the digestion suppressing effect cannot be exhibited. The curing temperature is preferably 30 ° C. or lower, and if it exceeds 30 ° C., the organic solvent in which the silane coupling agent is dissolved evaporates, and further, the silane coupling agent solidifies, and the silane coupling agent is contained in the basic refractory raw material. It is difficult to penetrate, and as a result, the digestive suppression effect is not exhibited.

The drying performed after curing is 100 to 200.
C. is preferred. If the temperature is lower than 100 ° C., the dehydration condensation reaction between the basic refractory raw material and the silane coupling agent does not occur, and the residual water causes a hydration reaction with the basic refractory raw material with heating during use, which is not preferable because a digestion phenomenon occurs. .
When the temperature exceeds 200 ° C., rapid dehydration occurs, and the silane coupling agent is not sufficiently adhered to the surface of the basic refractory, so that no digestive suppression effect is obtained.

Next, the invention according to claim 2 will be described. The basic amorphous refractory of the present invention is a basic refractory raw material that has been subjected to a surface treatment with the silane coupling agent described above,
A binder and a surfactant are kneaded with predetermined water.
Since the surface of the basic refractory raw material coated with the silane coupling agent exhibits hydrophobicity, it is poorly adapted to water at the time of kneading, so that the workability is reduced and the pouring becomes difficult. Therefore, in the present invention, a surfactant is added at the time of kneading in order to improve the compatibility between the basic refractory raw material surface-treated with the silane coupling agent and water.

The type of surfactant used in the present invention includes, for example, sodium naphthalenesulfonate, sodium alkylbenzenesulfonate, and sodium polyacrylate.

The addition amount of the surfactant is preferably 0.2 to 5.0 parts by weight based on 100 parts by weight of the kneaded material.
If the amount is less than 0.2 parts by weight, the effect of improving fluidity is not seen.
On the other hand, if it exceeds 5.0 parts by weight, a firing phenomenon is observed at the time of kneading, and as a result, an amorphous refractory construction body having many pores is obtained, so that the material strength is reduced and slag infiltration becomes severe. Causes a reduction in the life of the battery.

[0024]

EXAMPLES Examples and comparative examples are shown in Table 1 below to further clarify the features of the present invention.

Comparative Example 1 is a refractory currently used as a lining for a ladle slag line in the process. Comparative Example 2
As shown in Fig. 5, despite the surface treatment of the sintered MgO clinker, which is a basic refractory raw material, with a silane coupling agent, the curing temperature in the surface treatment exceeds 30 ° C, and the curing time is less than 1 hour. When the drying temperature is lower than 100 ° C. or higher than 200 ° C., the effect of suppressing the digestion of the sintered MgO clinker is not recognized. Further, as shown in Comparative Examples 6 and 7, the amount of the surfactant added was less than 0.2 parts by weight, or 5
If the amount is more than 1 part by weight, the basic refractory raw material sintered MgO
The surface treatment of the clinker with the silane coupling agent significantly reduces the tap flow and decreases the fluidity during kneading.

On the other hand, as shown in Examples 1 to 6, sintered MgO clinker, which is a basic refractory raw material, was subjected to a surface treatment with a silane coupling agent, and a curing temperature of 3%.
0 ° C or less, curing time 1 hour or more, drying temperature 100 ~
By using a material dried at 200 ° C. for 1 hour or more, digestion resistance is improved. Further, by adding 0.2 to 5 parts by weight of a surfactant during kneading, a decrease in fluidity during kneading is suppressed.

[0027]

[Table 1A]

[0028]

[Table 1B]

[0029]

[Table 1C]

[0030]

[Table 1D]

Notes to Table 1: 1) Surface treatment method: (1) Silane coupling agent: γ-glycidoxypropyltrimethoxysilane (2) Immersion time × pressure: 12 hours × 1 atm 2) Drying time: 24 hours 3) Slag infiltration resistance index: The slag infiltration amount of Comparative Example 1 was 1
4) Digestion resistance index: Index of weight gain before and after the test of Comparative Example 1 as 100 (higher value is better) -Test conditions- (1) Slag resistance infiltration Resistance test: Immersion in slag (C / S = 3) at 1700 ° C. × 4 hours (2) Digestion resistance test: 4 at 200 ° C. under saturated steam pressure
8 hours hold

[0032]

As described in detail above, according to the present invention,
It blocks the contact between foreign moisture and the basic refractory raw material, suppresses the digestion of the basic refractory raw material, and reduces the fluidity due to the surface treatment of the silane coupling agent by adding a surfactant during kneading. The present invention can be said to be an industrially valuable invention because it can suppress the formation of the molten metal and can provide an excellent refractory lining for a container for molten metal.

Claims (2)

[Claims] 1. A surface of a basic refractory raw material containing at least one of MgO and CaO is coated with an organic solvent in which a silane coupling agent is dissolved, and then cured at 30 ° C. or less for 1 hour or more. A surface treatment method for a basic refractory raw material, wherein the method is dried for 1 hour or more. 2. The surface is coated with an organic solvent in which a silane coupling agent is dissolved, then cured at 30 ° C. or less for 1 hour or more, and further dried at 100 to 200 ° C. for 1 hour or more.
To a basic refractory raw material containing at least one kind of MgO and CaO, a binder and 0.2 to 5.0 parts by weight of a surfactant are externally added to 100 parts by weight of the kneaded material, and an appropriate amount of water is added. A method for producing a basic amorphous refractory having excellent digestion resistance, which is characterized by being kneaded with a refractory.