JPS58190875A - Castable refractories - Google Patents

Abstract

(57) [Summary] This bulletin contains application data before electronic filing, so abstract data is not recorded.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to castables, and more particularly to castables for painting, and an object of the present invention is to provide an improved castable that prevents efflorescence after construction.

Traditionally, castables for troweling used in high-temperature environments generally consist mainly of coarse and medium particles of fused alumina as shown in the table, with 30% by weight of alumina cement added, and If necessary, in order to improve the troweling properties (workability), about 1 weight of beta/tonite or fireclay is added to the outer layer. However, when a duct is constructed by adding the required amount of water and kneading the mixture with a trowel, 7 to 1 days after curing, white fibrous substances grow in spots on the surface, causing the construction to deteriorate. The so-called Nikka phenomenon occurs in which the surface layer of about /θ swells and deteriorates. In even worse cases, the strength of the constructed structure may decrease and the construction may have to be repeated.

Although the cause is not very clear at present, it is thought to be as follows. That is, when the construction body dries, calcium aluminate hydrate, which is the main component of alumina cement, is gradually dissolved in the added water that moves to the surface. On the other hand, CO and gases in the air diffuse from the surface of the construction body toward the inside, so the above-mentioned wood
0aOO is generated where it coexists with objects, causing an efflorescence phenomenon. In addition, this phenomenon also occurred in the evening when Na2O in molten alumina
It is further promoted when the component is 0.14 or more.

The inventors have conducted various studies to solve these problems, and have found that calcium aluminate hydrate has been found to reduce carbon in the air.
This invention was completed based on the finding that it is sufficient to block the intrusion of O2 gas so that it does not come into direct contact with it.

This invention is a castable product characterized by adding a water-soluble polymer binder in an amount of θ, oi to θ, OS weight % to a composition consisting of alumina and alumina cement containing 0.14 or more Na and O. Exists in refractories.

The castable refractory of the present invention has Na, 0, which is generally used in castables. A commercially available water-soluble polymeric binder is added to the fused alumina containing more than
/~o, ozxx is added, and 00 in the air is added into the construction body.
□It is an easy-to-work type of paint that prevents gas from entering, and can prevent the efflorescence phenomenon described above for a long period of time.

Hereinafter, the present invention will be described in detail based on examples.

Examples As shown in the table, the castable refractories according to the present invention are made of, for example, coarse grains (3~/mm) of fused alumina! ;0
30% by weight of alumina cement is mixed with 0% by weight of medium grains (/m or less), and 0005% by weight of a water-soluble polymeric binder such as methyl cellulose is added as an outer layer.

As a fire-resistant material, castable for high-temperature troweling generally has a high corrosion resistance due to its low impurities and high corrosion resistance. The best choice is fused alumina of the
It can be blended in the required ratio according to the purpose. Note that when Na and O are less than 74, there is almost no effect of promoting the efflorescence phenomenon, so the blending ratio was limited as described above.

In addition, alumina cement is most suitable as a hardening material because it has a particle size that is highly corrosion resistant and has good scouring properties, and the blending ratio with the refractory material can be changed arbitrarily.

Furthermore, as a water-soluble polymeric binder, in addition to the above, one type can be appropriately selected from powdered P, V, A (polyvinyl alcohol) and carboxymethyl cellulose, but in which case However, if the amount added is less than 0.07% by weight, it is too small to be mixed evenly with fireproof materials, resulting in poor workability and efflorescence may occur within 3 days after construction. If it exceeds the OS weight %, the adhesiveness becomes too strong and the trowel separation becomes difficult, making it difficult to perform υ construction, so the above range is preferable. It was confirmed that within this range, the physical properties (test results) of the constructed object would hardly change.

Next, when the castable of this invention was mixed and mixed with 72 to 75% water on the outside, it was applied with a trowel to the inside of a duct, etc. to which a serpentine locking metal fitting had been welded in advance. Workability was no different from conventional products, and construction was possible smoothly without any spillage. Also,
When the water-soluble polymeric binder dissolved in the added water dries,
Because CO2 in the air seeps onto the surface of the construction object and solidifies there to form a strong film, as mentioned above, CO2 in the air cannot diffuse into the interior, so the reaction with calcium aluminate hydrate, i.e. Efflorescence can be prevented for a long time.

Therefore, even if the construction period becomes slightly longer, or if the operating conditions suddenly change after construction and the construction is not operated for a long period of time, the strength of the construction body will not deteriorate and it can be used as is without any problems.

As detailed above, the castable refractory of the present invention is made by adding a small amount of a water-soluble polymeric binder to the composition grains consisting of fused alumina grains and alumina cement containing 0.1 inch or more of NIL20. It is a castable castable material for use in the field of rice, which has good workability and is excellent in its ability to prevent efflorescence for a long period of time.

Patent applicant Shinagawa White Brick Co., Ltd. 7)

Claims (1)

[Claims] A water-soluble polymeric binder is added to a composition containing 0.1% or more of Ma2O and composed of Kyudenko alumina and alumina cement at an outer layer of 0.0/~O,O! A castable refractory material having a weight of 1L.