JPS6086080A - Carbon-containing basic 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 a carbon-containing basic castable highly flammable material that is excellent in oxidation resistance, spall resistance, corrosion resistance and strength.

In recent years, basic castable refractories have been rapidly replacing bricks from the viewpoint of labor and energy conservation. However, recently, it seems that this power booster has reached its peak. One of the reasons for this is thought to be the sluggish growth of basic castable refractories.

Although basic castable refractories have sufficient corrosion resistance against basic slag, they are susceptible to thermal spalling due to their large coefficient of thermal expansion, and are susceptible to structural spalling due to large slag infiltration.

As a means to improve these points, ψrie is using Tokukai Akira,! There is a method using carbon, as shown in Japanese Patent No. 17-9aski. The invention described in the above-mentioned Gikaisho publication uses aggregate "yg to 6S by weight with an MgO content of SO% or more and 5 to 35 parts by weight of graphite, and a condensed sodium phosphate binder and high alumina cement as binders. This is what I used.

In other words, carbon-containing refractories exhibit extremely excellent corrosion resistance against chemical attack due to the property of the platform carbon being difficult to wet when it comes into contact with hot metal, molten steel, slag, etc. In addition, the presence of carbon prevents oversintering of large objects, making thermal spalling less likely to occur.

However, carbon oxidizes very easily in the presence of oxygen in the atmosphere and loses all of the above-mentioned excellent properties of carbon. In particular, when carbon, which is difficult to wet with water, is added to castable refractories, the amount of water in the construction increases and the structure deteriorates, so this tendency is more severe than with homogeneous bricks.

As a solution to these problems, the technique of adding a metal that has a higher affinity for oxygen than carbon is known, for example, as disclosed in Japanese Patent Application Laid-Open No. 33-1973.
Kudata No. 107 discloses that the addition of magnesia powder, aluminum powder and silicon powder is effective. However, the invention described in the Wakasho publication does not use any brick-refining water using a non-aqueous binder.

However, in the case of castable refractories, since water is used as a construction medium, it reacts violently with the @stripe and the following water usage reaction, generating H2 scum LA2Mg+2I (20-+M
g(OH)2+H27A engineering+3H20-+AJ! ,(0
)() R+τH2↑Si+jH20→81 (OH)
4+H2↑ Destroy the organization. In addition, due to the above water utilization reaction, the entire island becomes a total set of hydrates, and the antioxidant effect of carbon is completely eliminated. For these reasons, the technique disclosed in Japanese Patent Application Laid-open No. 1983-10-7-9 cannot be applied to castable refractories.

On the other hand, the inventors, as co-applicants, %KaishojT! 1
9361/, it is proposed and known to suppress or completely eliminate the hydration reaction with water by using aluminum coated with a resin in advance. but,
Refractory aggregate or alumina negative, clay chamotte, silicon carbide,
pH of a mixture of neutral to acidic refractory aggregate such as Joka Silicon and water
F13~ is effective in suppressing the water use reaction of aluminum, but in a mixture of water and basic refractory aggregates such as magnesia, pyromite, and spinel, Mg or Ca ions are eluted and the pH becomes 10 or more, which inhibits the water use of aluminum. There is a drawback that reaction suppression effect cannot be obtained.

Therefore, the present inventors conducted various research on these points and found that -81 and kl-8i, AJ-Mg alloys have little water utilization reaction in solutions with pH > 10, and these Si and AJ-8i, A carbon-containing basic castable refractory with excellent oxidation resistance, spalling resistance, corrosion resistance, and strength, as it has been confirmed that there will be no water-recycling reaction in a solution with a pH of 0.00000 by pre-coating A4-Mg alloy with resin. This is what we have come to complete.

That is, although the carbon-containing basic fireproof aggregate of the present invention is mainly used, oxides such as alumina, silica, and zirconia, and non-oxides such as silicon carbide and boron carbide can also be used, and there are no particular limitations. isn't it. As carbon, raw graphite, natural graphite such as scaly graphite, or artificial graphite such as electrode scrap, petroleum coke, and carbon black can be used. From the viewpoint of reducing the amount of water in construction and densifying the structure, raw coke containing menface can be used. And petroleum coke obtained by heat-treating this raw coke is most preferred. The blending ratio of carbon varies depending on the purpose of use, but is preferably 2 to 30 parts by weight. That is, if the area is less than λll, carbon cannot sufficiently exhibit its wettability with respect to molten steel and slag. Moreover, if it exceeds 30 parts by weight, the amount of water in the construction increases, resulting in insufficient strength and structure.

In addition, as a carbon oxidation preventive or alloy, carbon has a high affinity for oxygen and pH).
Sl and A4- with small reaction in solutions of 70 or more
8i, A4-Mg, and one or more types of metal and alloy powder coated with water-insoluble resin such as asphalt pitch, tar pitch, and novolak type phenolic resin can be used. The amount of metal ν and alloy added is 0.
5 to 7 parts by weight is desirable. In other words, sufficient effects cannot be obtained outside this range.

The carbon-based basic castable of the present invention contains a dispersant such as condensed sodium phosphate, a deflocculant, and an alumina cement hardening modifier such as citric acid and ca(OH)2 to improve workability. In addition, a small amount of whole-island aluminum or the like as a wire transfer accelerator may be added.

Examples of the carbon-containing basic castable refractories of the present invention are shown below in comparison with conventional products. Pour into the frame of 40 sake, and after curing for cog time, 10! After drying at i° C. for 21 I hours, the test samples were subjected to bending strength and oxidation tests after heating.

From this, it can be seen that the bending strength of the product of the present invention from the medium temperature range to the high temperature range is greatly improved by 2 to 3 times compared to the comparative product, and the oxidation property is also greatly improved by raJ.

Procedural Amendment Written November 18, 1982 Dear Commissioner of the Japan Patent Office 1, Indication of the Case Patent Application No. 1, 1982? λ373 No. 3, Relationship with the case of the person making the amendment Patent applicant name (/??) Shinagawa Shirorenga Co., Ltd. (1) Contents of the amendment to the detailed description of the invention in the specification #I, page 8 Silk/Table left column 1- HP・Mg alloy (A1
−Mg=:) J to r AJ・Mg alloy (AJ/Mg ratio=
///Bulk pressure with the moon.

Claims (1)

[Claims] 2 to 30 parts by weight of carbon, 63 to 97 parts by weight of basic fireproof aggregate.
5 parts by weight of resin coated Si, Aj-8i. 1. A carbon-containing basic castable refractory characterized by containing 7 parts by weight of one or more of Aj, -Mg and O, S.