JPS5935068A - Basic castable - 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 basic castable that is dense and exhibits excellent effectiveness in preventing the penetration of particles or slag.

In recent years, from the perspective of energy conservation, the use of monolithic refractories, which are highly flexible in construction, has increased significantly.
In particular, as refractories in the steel manufacturing industry, basic materials,
In particular, magnesia-based materials are often used.

However, magnesia refractory materials have a large f% penetration of steel and slag, and have the disadvantage of being prone to structural spalls.
Although the above-mentioned drawbacks have been improved by combining carbon materials with basic refractory materials, a new problem has arisen in that the addition of carbon materials causes deterioration of molded products due to oxidation. Recently, attempts have been made to add metal powder to the carbon material in order to summarize these factors and increase the oxidation prevention IF and strength.

Metal powder tends to selectively react with oxygen and form a dense layer on the surface of refractories, preventing oxidation and increasing strength. However, when basic castable made from magnesia is mixed with water, In case, pH of magnesia slip
becomes strongly alkaline with a value of about 11, and gold R by normal means.
If used in combination with a powder, it will react during curing or drying, causing heat generation and foaming, making the structure of the refractory porous.If this is severe, cracks and explosions may occur, making it impossible to obtain a stable molded product. I woke up. On the other hand, as a way to overcome this phenomenon, various chemicals are used to adjust the pH.
Attempts have been made to prevent the above phenomenon by suppressing the reaction, but when the product temperature exceeds 85°C, the effect of suppressing the reaction disappears, and the reaction between the metal powder and magnesia slip J: is completely stopped. It was not possible.

In view of the current situation, the present invention includes the addition of a metal powder that prevents oxidation and increases strength of magnesia Ig (refractory 4) I (7) in addition to carbon, which causes a reaction with magnesia slip. Proposal for basic refractories made without 1.-U dust, specifically using metal powder whose surface has been treated with rIiΦ coating, which solves the conventional problems. The purpose of this invention is to solve this problem and provide a new basic castable that is dense and has excellent effects when penetrating slag, etc.

Hereinafter, examples of implementation of the present invention will be described in detail.

The surface is treated with oxide 11. The metal powder is melted and then subjected to acid treatment or oxidation treatment. 1 Father d of silicon, metal aluminum, etc.
2a+ or higher can be used, and among these, ferrosilicon is useful, and commercially available products such as OC1) Force 1 manufactured by Imao Kogyo Co., Ltd., Niferon Recon, 0CD7J11 Emetasiri, etc. can be used for f cars.

The particle size of the metal powder treated with this surface oxide coating is:
In order to be stable in reactivity, it is preferable to use one with a molecular weight of 0.125 or less. At the same time, the addition instant is 05~
In the case of 10-layer seams, the effect of addition is not observed for 0.5-thick and 14-thick seams or less, and for 1-thick seams, the structure deterioration is severe and the corrosion resistance is significantly reduced.
Within the above range, it is easy to obtain good results especially when the weight ratio is between 1 and 5 for fire-resistant materials.

As the magnesia raw material, natural magnesia, seawater magnesia, fused magnesia, etc. can be used, and the amount used is 60 to 98 gm. This fine weather is 60 heavy j of fireproof material.
If it is less than t, the corrosion resistance will be impaired when combined with basic slag, and if it is more than 98 ton, it is unsuitable from the viewpoint of structural spall due to penetration of slag.

As the carbon raw material, natural graphite, artificial graphite, or skeined petroleum coke can be used, and the additive II/'i2 to 20% by weight (
Preferably it is 3 to 10 tons. If it is less than 2%, the effect of the carbon material addition described above will not be sufficient, and if it is more than 20%, the strength and oxidation resistance will decrease, and fluidity will become poor, which is not preferable.

Furthermore, pitch, phenol resin, or the like may be added up to 5 times to form carbon bonds, if necessary. However, if the temperature exceeds 5 degrees, there is a concern that cracks or explosions may occur during the drying of the refractory material.

Furthermore, it is preferable to add up to 10% by weight of silicon carbide having a particle size of 0.125 rim or less as an antioxidant aid. Addition of this adjuvant should be avoided if the amount exceeds 10 ml, as eating quality will be extremely reduced.

In the castable of the present invention, although the addition of ultrafine silica powder is not essential, it improves fluidity and promotes densification.
Addition to rice is advantageous. As the ultrafine silica powder, amorphous silica obtained as a by-product during the production of ferrosilicon, etc. can be used, and it is effective to add the silica to a concentration of 5 times or less. Addition of TiL exceeding 5% by weight tends to cause cracks or explosions during drying, and the corrosion resistance is significantly reduced.

The above-mentioned ingredients are blended, and in order to lower the F of the standard mixed water of this compound and enable low-moisture casting, the well-known glue gunin snolin salt, etc., which has a water-reducing effect without impairing workability, etc. 0.1-1.0% by weight of surfactant
Also, it is preferable to add 0.05 to 0.5 weight tS of a well-known dispersant such as polyacrylic acid or sodium phosphate to improve the properties during use.

Next, the reactivity of the metal powder treated with the surface oxide film and magnesia slip in the present invention was compared with that of the untreated metal, and the results are shown in Table 1. It can be seen that the effect of suppressing the reaction is remarkable.

Table 1 Reactivity with magnesia slip depending on the state of metal powder The particle size of magnesia mill powder in this comparative test is 0.
．． 044 ays, the bottom is 80 inches, and the particle size of all metals used was 0.074 a or less. The formulation is heavy slippery and the added water is added externally.

After adding a specified amount of water to such a mixture, it was kneaded for 5 minutes to prepare a test sample. After placing the sample in a beaker and sealing it, it was kept in a constant temperature bath at 40°C for 20 hours, and changes in the state were visually observed and verified. As shown in Table 1, the results showed that no reaction was observed in Oku 1 and Kuro 2, which were added with metal powder treated with a surface oxide film, but all of Todoroki 8 to 5, in which untreated metal powder was added, did not react. Foaming phenomenon was observed. For special K A4 and A5, the samples lost their fluidity and solidified.

Next, an example of actual Mli based on the results of this comparative test will be shown. The formulations of Examples 1 to 5 are as shown in Tables 2 and 4, and the physical properties of the molded products obtained from the Examples of each formulation are as shown in Tables 8 and 5. there were. Comparative example ``l'' which also contains untreated metal powder
The composition and physical properties of the molded product are shown as ``l C1dl e, f, and g.

In the physical property tests in Examples and Comparative Examples, dry blocks for the block drying test were produced by mixing in a mortar mixer, then adding water and kneading, and pouring into an iron frame while applying vibration. After leaving it for 10 hours, it was removed from the frame and dried at 300° C. for 10 hours in a small dryer. The pieces for oxidation tests and for measuring film physical properties were mixed in a universal mixer, then kneaded with water, and mixed with 50φ while adding perturbation.
x50mg and cast into a mold of 40 x 40 x 160 yM. After being left for 10 hours, the frame was removed and dried in an atmosphere at a temperature of 110° C. for 24 hours.

In Examples 1 to 5, there were no cracks, blisters, or explosions during drying, and even though the surface oxide coating was applied, the anti-oxidation effect and the increase in strength after firing due to the addition of metals were also observed.

As shown by the above results, Examples 1 to 5 had no cracks, blisters, or explosions during drying, and even though the metal powder was treated with a surface oxide film, the oxidation prevention by metal addition was It was confirmed that the effect and the increase in firing strength were remarkable compared to those of Comparative Examples 3 to g, and that they exhibited excellent properties.

Claims (1)

[Claims] A basic castable characterized by adding metal powder whose surface has been treated with an oxide film to an element-containing magnesia refractory composition.