JPH0788260B2 - Castable refractory - Google Patents

Description

TECHNICAL FIELD The present invention relates to a castable refractory material having high strength and easy to handle.

[Conventional technology and its problems]

Conventionally, there is one that uses alumina cement and silica flour as a high-strength castable refractory. As the silica flour, for example, as described in JP-A-57-172181, it is customary to use those by-produced during the production of Fe-Si, and the amount of impurities varies depending on the incoming lot, Moreover, its purity is low at about 90%. For this reason, when a large amount of silica flour is used, the fire resistance is lowered, and the flowability of the refractory mixed with water and the curing time vary.

In order to solve such a problem, instead of silica flour, for example, as shown in JP-A-54-18820,
It has been proposed to use silica gel.

However, silica gel is very sensitive to changes in pH, and it is observed that phenomena such as co-use with alumina cement, or coagulation during kneading in the presence of an electrolyte are observed.
Very difficult to handle.

In order to solve such a problem, for example, Japanese Patent Laid-Open No. 61-
As described in Japanese Patent No. 10076, a combination of alumina cement and amine silicate has been proposed as a high-strength castable refractory. The amine silicate used in this conventional example is an aqueous solution having a concentration of about 35 to 40%, and is further diluted with water at an arbitrary ratio at a construction site before use.

The castable refractory material in which the alumina cement and the amine silicate are used in combination has advantages such as high strength, excellent volume stability, and easy handling because the curing time can be adjusted appropriately.

However, since the amine silicate described in JP-A-61-10076 is handled in the form of a highly viscous stock solution having a concentration of about 35 to 40% obtained by reacting colloidal silicic acid and amine in a liquid, A binder solution tank that stores the amine silicate stock solution together with dilution water and a chemical pump that supplies the diluted amine silicate to the mixer containing the refractory mixture with a certain accuracy from the solution tank must be installed at the construction site. In addition, when diluting the above-mentioned amine silicate stock solution, it is necessary to surely grasp the substantial amount of amine silicate contained in the stock solution and then dilute it at a predetermined magnification at the construction site, unless a specified amount for the refractory composition is reached. Since it is not possible to add the amine silicate of the There is a possibility that excess or deficiency occurs in the amount of over bets.

The present invention has been proposed in view of the above circumstances, has a high strength, is easy to handle, and castable refractory that is easy to handle and does not require dilution that is error-prone. It is intended to provide.

[Means for solving problems]

The castable refractory according to the present invention is, on the premise that the amine silicate is added to a refractory composition containing 1 to 10% by weight of alumina cement in order to achieve the above object, and the amine silicate is It was powdery, and 0.1 to 3 parts by weight was added to 100 parts by weight of the refractory composition. Furthermore, the present invention is also applicable to castable refractories in which silica flour is added to the above refractory composition.

[Work]

The castable refractory of the present invention configured as described above,
Since the amine silicate is added to the refractory composition in the form of powder in advance, it is sufficient to simply knead with the kneading water at the construction site, and the equipment for diluting the amine silicate is not necessary, and Since an appropriate amount of addition can be determined based on the weight, there is no risk of excess or deficiency in the addition amount.

Further, since the amine silicate itself has stability against pH fluctuation, when the amine silicate kneads the refractory mixture, it does not rapidly cure even if a hardening agent such as cement is added, Is easy. Further, the components are almost the same as those in the case of using the amine silicate aqueous solution, and the characteristics are almost unchanged.

The refractory composition used is, for example, a refractory aggregate and alumina cement, or those containing silica flour in addition to these. This refractory aggregate may be appropriately selected from the refractory aggregates used for ordinary castable refractories according to the purpose, and examples include bauxite, mullite, chamotte, pyrophyllite, silica stone, zircon, and zirconia. You can

The above-mentioned alumina cement mainly functions as a curing agent and a binder, and the quality thereof is not particularly limited. For example, a super grade (Al ₂ O ₃ 80
%, CaO18%), high alumina grade (Al ₂ O ₃ 73%, CaO25
%) No. 1 cement, No. 2 cement (Al ₂ O ₃ 52 to 63%, CaO ₃
5 to 45%) is used.

The amount of alumina cement used is 1-10 in the refractory mixture.
A range of weight percent is suitable. If it is less than 1%, curing will be slow,
If it exceeds 10% by weight, the fire resistance and the volume stability are deteriorated, and at the same time, there is a risk of explosion during rapid drying. Further, when a basic material is used as the refractory aggregate, the curing time of the castable refractory material is slightly shortened, so that the alumina cement content is preferably about 1 to 3% by weight in the refractory compound.

The amount of silica flour added is 0.5 to 1 in the refractory mixture.
It is preferably about 0% by weight, more preferably 1 to 7% by weight. If the addition amount is less than 0.5% by weight, the effect of improving strength and fluidity due to the addition becomes small,
If it exceeds 10% by weight, the fire resistance decreases and the shrinkage increases, which is not preferable.

The powdered amine silicate is obtained by, for example, replacing Na of colloidal silicic acid (Na ₂ O · 3SiO ₂ ) with an amine having a neutral alkyl group (NH ₂ C _n H _2n ) and then dehydrating the reaction solution. is there. In this reaction solution, by adapting the structure of the alkylamine to be substituted and the addition amount to specific conditions, the silica surface is covered with the alkylamine, and it can be pulverized without gelation during dehydration,
When the obtained powdery amine silicate is hydrolyzed, it immediately becomes a sol and exhibits a function as a binder.

The powdered amine silicate is suitably added in an amount of 0.1 to 3 parts by weight based on 100 parts by weight of the refractory composition. If the amount added is less than 0.1 parts by weight, the reaction with the alumina cement causes rapid hardening and the strength is also lowered, which is not preferable. If the amount added exceeds 3 parts by weight, the curing time becomes too long and the time of shrinkage increases, which is not preferable. Further, when a basic material is used as the refractory aggregate of the refractory composition, the curing time of the castable refractory is slightly shortened, so that the powdered amine silicate is used as the refractory composition 100%.
It is suitable to add 1-2 parts by weight to parts by weight. If the addition amount is less than 1 part by weight, the reaction with the alumina cement causes rapid hardening and the strength is also lowered, which is not preferable. If the amount added exceeds 2 parts by weight, shrinkage becomes large, which is not preferable.

In the present invention, it is also possible to add a surfactant, a dispersant, etc. to the extent that the hydraulic properties of the alumina cement are not impaired.

Examples 1 and 2 Table 1 Table 1 After mixing with 100 parts by weight of a refractory composition having components shown in the columns of Examples 1 and 2, 0.6 parts by weight of powdered amine silicate and an appropriate amount of water were added and kneaded. , 40mm × 40mm × 16
Pour into a 0mm rectangular mold and let it cultivate at room temperature (20 ℃) for about 1 day. After being dried, it is dried at about 110 ° C. for about 24 hours to form a dry refractory material. A calcined refractory is obtained by further calcining the dried refractory at about 900 ° C. or about 1500 ° C. for about 3 hours.

For the refractory thus obtained, the linear change rate according to JISR-2554, the porosity according to JISR-2205, the JISR-25
Compressive strength and flexural strength were measured according to 53, and the results are shown in Table 2 for comparison with Comparative Examples 1 and 2 described later. The curing time after kneading was measured for each example, and the results are shown in Table 2 in comparison with Comparative Examples 1 and 2 described later.

Comparative Examples 1 and 2 As Comparative Examples, 100 parts of the same refractory mixture as in Examples 1 and 2 was added with the amount of the amine silicate aqueous solution shown in Table 1, and the same procedure as in Examples 1 and 2 was performed. , Dry refractory, 900 ℃
A fired refractory and a 1500 ° C. fired refractory were prepared and their physical properties were measured.

From Table 2, according to each example using the powdered amine silicate, the curing time was the same as that of the comparative example using the amine silicate aqueous solution, and the mechanical strength was almost equal to or higher than that of the comparative example. You can see that you can get it.

〔The invention's effect〕

As described above, the castable refractory material according to the present invention has high strength, excellent volume stability, and is easy to handle because it cures in an appropriate curing time. However, since the powdered amine silicate is used instead of the amine silicate aqueous solution, it is not necessary to dilute the amine silicate in the field, the field work can be simplified, and the dilution ratio does not become erroneous.

Claims (2)

[Claims] 1. A castable refractory made by adding an amine silicate to a refractory mixture containing 1 to 10% by weight of alumina cement, wherein the amine silicate is powdered, and 100% by weight of the refractory mixture. Castable refractory, characterized in that 0.1 to 3 parts by weight is added to each part. 2. A castable refractory made by adding an amine silicate to a refractory composition containing 1 to 10% by weight of alumina cement and 0.5 to 10% by weight of silica flour, wherein the amine silicate is in the form of powder. A castable refractory, characterized in that 0.1 to 3 parts by weight is added to 100 parts by weight of the refractory composition.