JPS61141676A - Monolithic 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 Field of the Invention The present invention relates to a monolithic refractory containing metal powder.

Prior Art and its Problems In recent years, various attempts have been made to add metal powder to improve the quality of monolithic refractories. For example, in monolithic refractories to which 8iC is added to provide thermal shock resistance and chemical reaction resistance, 8iC is oxidized to 810 atoms in a high-temperature oxidizing atmosphere, causing expansion and cracks in the refractory. In order to prevent this, methods of adding metal silicon or metal powder such as ye-8i have been attempted. In this method, the added metal powder oxidizes faster than SiC, thereby suppressing the oxidation of SIC, and furthermore, the oxidation product of the metal powder uniformly covers the SiC surface to prevent oxidation of 8iC. The purpose is to prevent the occurrence of cracks in large objects. In addition, in pouring materials that use fireclay as a binder, the clay decomposes when heated, producing glass components, which can cause a decrease in the strength of the structure. To deal with this, adding aluminum powder suppresses the formation of glass and at the same time forms a direct bond mainly composed of silicon carbide and corundum.
Attempts have been made to improve hot strength. However, when metal powder is added to monolithic refractories like this, the metal powder may cause the following water use reaction when mixed with water.

M +nEI20→M(OH), + l nH2n+ The hydrogen generated by this reaction inhibits the densification of the constructed body during curing by casting, and causes blistering and cracking of the constructed body. For this reason, refractories do not have sufficient sinterability or strength, the added metals do not have sufficient effect of preventing oxidation of silicon carbide, carbon, etc., and furthermore, the generated hydrogen poses a risk of explosion. There is also.

As a ninth attempt to solve such problems, attempts have been made to suppress the hydration reaction by coating metal powder with resin etc.
578% JP-A-58-199770, JP-A-58-22
70). Known resins used for this purpose include phenolic resins, 7-run resins, xylene resins, epoxy resins, melamine resins, acrylic resins, and silicone-containing resins such as dimethylsilane, sodium methyl siliconate, and silicone resins. It is being However, these resins generally have a high viscosity, making it difficult to uniformly coat metal powder, and also tend to form lumps. When a lump is formed in this way, there is a problem that when the lump is crushed, the metal powder having an uncoated portion is exposed on the fractured surface caused by the crushing, and the coating layer is destroyed in the crushing process. Furthermore, a method of adding a solvent and using a curing agent etc. in order to lower the viscosity of the resin is considered, but the coating process becomes complicated and it is difficult to form a uniform coachib film.

Another method is to melt an organic resin or pitch with a relatively low melting point, add metal powder, knead it, cool it, and crush it, but since it requires a crushing process, metal powder with uncoated parts can be used. However, the present inventor has developed a monolithic refractory containing metal powder, which suppresses the water use reaction of the metal powder and is difficult to manufacture because it includes a melting process and a grinding process. As a result of intensive research to prevent the occurrence of harmful effects, we have found that by using a specific paint, it is possible to easily form a coating film on metal powder with good uniformity. By using metal powder coated with this paint, the hydration reaction of the metal powder is suppressed, and a dense and high-strength construction body can be obtained, and the effect of adding the metal powder can be fully demonstrated. I found out that it can be done.

That is, the present invention provides an amorphous material containing a paint-coated metal powder obtained by coating 100 parts by weight of metal powder with a solid content of 0.5 to 15 parts by weight of at least one of oil-based paint, cellulose derivative paint, and synthetic resin paint. Related to refractories.

In the present invention, at least one of an oil-based paint, a cellulose derivative paint, and a synthetic resin paint is used as the paint for coating the metal powder.

Oil-based paints are those that use drying oil as a film-forming element, with pigments and drying agents added as necessary.Specifically, they include casein oil, oil, soybean oil, oil-based oil, Examples include those using linseed oil or the like as a coating film forming element.

Cellulose derivative paint is a film-forming element made of cellulose conductor, to which resins, pigments, alcohol solvents, etc. are added. Cellulose, ethyl cellulose, etc. are mainly used.

A synthetic resin paint is one in which a synthetic resin is used as a coating film-forming element, and is treated with a solvent, pigment, etc. Examples of synthetic resin paints that can be used in the present invention include the following: 0 The numbers in parentheses indicate the main coating film components.

a) Phenol resin paint (resin-modified phenol formaldehyde resin, alkylphenol resin, etc.) b) Alkyd resin paint (oxidized oil-modified alkyd resin) C) Amino alkyd resin paint (melamine resin, urea resin) d) Guanamine resin paint (benzoguanamine resin) , alkyd resin, etc.) e) Vinyl chloride resin paint (polyvinyl chloride, polyvinyl acetate, etc.) f) Styrene-butadiene copolymer resin paint (styrene-butadiene resin) g) Epoxy resin paint (epoxy resin) h) Unsaturated polyester Paint (Unsaturated Polyester) i) Polyurethane Resin Paint (Polyurethane Resin) In the present invention, among the nine paints mentioned above, air-hard and quick-drying paints are preferred, and cellulose derivative paints are particularly preferred.

In the present invention, the amount of coating material to be coated is 0.5 to 15 parts by weight as a solid content of the coating material based on 100 parts by weight of metal powder. Further, in the present invention, if necessary, a refractory raw material having a particle size of 1 rffn or less may be added to the metal powder, and this mixture may be coated with a paint for use. In this case, the refractory raw material exhibits the effect of preventing the metal powder/powder from forming into lumps 9.

When coating a mixture of metal powder and refractory raw material with a particle size of 1 mm or less with paint, the amount of refractory powder in the mixture should be 50% by weight or less, and the coating amount of paint should be 100% by weight of the mixture. The solid content of the coating material is 0.6 to 16 parts by weight. In the present invention, the viscosity of the paint can be adjusted to an appropriate level by adding 1 to 10 parts by weight of thinner, if necessary.

Paints are usually diluted with a solvent, so when diluting with thinner, it can be easily diluted. Therefore, if the viscosity of the paint is high and lumps are likely to occur, the viscosity can be easily adjusted, and by using a paint with an appropriate viscosity, lumps will not form during the coating process. can be prevented and a uniform coating can be formed.

In the present invention, paint or a mixture of paint and thinner is added to a metal powder or a mixture of metal powder and a refractory raw material of 1 mm or less, kneaded, dried, and sized with a sieve, etc., so that the paint is applied uniformly. It is possible to obtain metal powder coated with As described above, in the present invention, since the occurrence of lumps due to coating can be prevented, a pulverization step is not necessary, and metal powder to which paint is evenly adhered can be obtained simply by sizing with a sieve or the like. Therefore, there is no destruction of the coating layer due to crushing, a uniform coating film with no uncoated parts can be formed, and the coating process can be simplified.

The various paints mentioned above generally have good adhesion, weather resistance, abrasion resistance,
They are made with consideration to chemical resistance, etc., and there are many types that have the effect of uniformly adhering to metal powder and preventing water utilization reactions.

Therefore, when coating metal powder with paint,
Another advantage is that it is possible to easily select a paint from a wide variety depending on the purpose of use.

The coating film made of the paint of the present invention has no uncoated parts and has good uniformity, so it has a great effect of suppressing the water use reaction when mixed with water. When the metal powder should be used, the decomposition of the coating film does not impede the action of the metal powder. Therefore, the additive metal powder can fully exhibit its effects. On the other hand, when forming a coachine film on metal powder using a resin diluted with a solvent, it is necessary to mix many different things such as the resin, diluent, hardening agent, etc., so the dilution work is not necessary. However, it is difficult to coat the metal powder uniformly with a resin that is simply diluted with a solvent to lower its viscosity, so it is difficult to sufficiently prevent the hydration reaction of the metal. Can not.

The metal powder to be coated with paint is not particularly limited, and various types can be used depending on the purpose, such as metal silicon.

PE-8In aluminum, magnesium, iron, nickel, titanium, etc. powders can be used, and the particle size is l m
The amount of the metal powder coated with the paint, which is preferably about 0.0 m or less, varies depending on the purpose of use, but is usually used in the refractory composition in an amount of about 0.5 to 15% by weight. For opaque paints, Oaoog, Tio2, Os P bO are used as pigments depending on the color.
Contains about lθ to 80% of rO4, lFe12Qg, etc.,
These pigments may become impurities depending on the composition of the refractory. However, if the amount of coated metal powder used is within the above range, the pigment will be less than about 0.6% by weight in the refractory composition, and it will hardly be a problem as an impurity. Does not contain
Alternatively, in a clear type paint that does not contain any metal powder, there are almost no impurity components, so even if more than 15% by weight of metal powder is added, problems due to impurities will not occur. The ingredients other than the metal powder are not limited, and nine raw materials can be used depending on the purpose of use of the refractory, and the friend metal powder coated with paint is not affected by the type of refractory raw material. The desired effect can be achieved. Examples of refractory raw materials include silica, alumina, magnesia, chromite, carbon, and silicon carbide.

Effects of the Invention According to the present invention, by using a paint, a uniform coating film can be formed on the surface of a metal powder in a simple process that does not require a pulverization process or the like. Further, the obtained coating film can fully exhibit the effect of adding the metal powder by decomposing it during heating.

Therefore, by using gold or W4 powder coated with paint instead of metal powder in monolithic refractories, it is possible to suppress the water use reaction of the metal powder when mixed with water, and to create a dense structure without blisters or cracks. A constructed body is obtained, and the sinterability and strength are improved, and the effect of adding metal powder can be fully exhibited.

Example The present invention will be described in detail below with reference to Examples.

Examples 1 to 5 A coating material consisting of a metal powder shown in Table 1 or a mixture of metal powder and alumina with a particle size of 1 mm or less was mixed with a paint, kneaded, dried for 2 to 16 hours, and coated with a powder of 1 mm or less.
A metal powder was obtained which was sized using a sieve and recoated with a paint. In Example 2, the coating raw materials were mixed in advance for 8 minutes, then thinner was added and preliminary mixing was performed for 8 minutes, and then the paint was added and kneaded. In Examples 8 and 4, the paint was diluted with thinner in advance and then added to the coating raw material and kneaded. In Example 6, the coating materials were mixed in advance for 8 minutes, and then the paint was added and kneaded.

In this way, using paint coating metal powder or a mixture of metal powder coated with paint and alumina, 66% by weight of magnesia below 1000 μm, 16% by weight alumina below 590 μm, and 10% by weight silicon carbide below 74 μm. A monolithic refractory composition was prepared consisting of 12% by weight of carbon of 1000 μm or less and 6% by weight of a mixture of nine metal powders and alumina coated with paint coating metal powder or paint.

After mixing this amorphous refractory composition, part of silica sol sIL as a binder aqueous solution was added and kneaded to 40%
It was molded by casting into a mold measuring 40 mm by 160 mm. When this was maintained at a temperature of 80° C. and cured, the degree of blistering of the constructed body and the presence or absence of cracking and its degree were observed. In addition, when the construction body was heated to 800°C with a propane-oxygen burner, the state of oxidation was visually observed, and those with an oxidized decarburization layer thickness of 3 + nm or more were judged as poor, and those with a thickness of less than 3 mm were judged as good. The chemical resistance was evaluated.

In addition, the porosity and bending strength of the construction body were measured after drying it at 110° C. for 24 hours. The results are shown in Table 2.

Table 1 Note) The amount of paint used is expressed in parts by weight of solid content.

Comparative Example 1 A test on a monolithic refractory was conducted in the same manner as in the example except that uncoated metal powder was used in place of the paint-coated metal powder. The results are shown in Table 2.

Comparative Example 2 A coating material consisting of 50 parts by weight of silicon and 50 parts by weight of alumina of 1 mm or less was coated with a diluted resin solution consisting of 4 parts by weight of polyester resin, 8 parts by weight of isocyanate, and 8 parts by weight of toluene, and then coated with resin. Specializes in mixtures of powdered metal powder and alumina. A monolithic refractory was tested in the same manner as in the example except that the resin-coated mixture of metal powder and alumina was coated with paint and used instead of the mixture of metal powder and alumina. The results are shown in Table 2.

Table 2 From Table 2, the refractory containing the metal powder coated with the paint of the present invention hardly causes any blistering or cracking on the constructed body, has excellent oxidation resistance, has low porosity, and has high strength. That is clear.

On the other hand, with uncoated metal powder or resin-coated refractories containing nine metal powders, blisters and cracks occur in the constructed body, poor oxidation resistance, high porosity, and low strength. Understand @ (more)

Claims (1)

[Claims] (1) 100 parts by weight of metal powder is mixed with a solid content of at least one of oil-based paint, cellulose derivative paint, and synthetic resin paint of 0.5
A monolithic refractory containing a paint-coated metal powder coated with ~15 parts by weight.