JPS59207870A - Magnesia carbon brick - 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 magnesia carbon fiber, and more specifically, it includes high purity magnesia clinker with an MgO content of 96% by weight or more and high purity scaly graphite with a fixed carbon content of 97% by weight or more of 50 to 10% by weight. % mixture, average particle size 20-2
00 mesh r--1-: carbon bond to which 05 to 10 parts by weight of metal magnesium powder is added, or further 0.1 to 10 parts by weight of metal aluminum powder with an average particle size of 200 mesh or less and a purity of 98 weight% or more is added. This relates to magnesia carbon bricks.

In recent years, the life of the furnace body in a converter has been significantly extended due to the adoption of magnesia carbon bricks, improvements in hot spraying technology, and implementation of slag control. However, the operating conditions of converters have become more severe due to increased continuous casting ratios, higher grade steels, combined blowing, slagless operation, etc., and more durable magnesia carbon bricks are required.

The carbonaceous material of the magnesia carbon brick in the part that comes into contact with the molten steel and slag of the converter is oxidized by FeO, MnO, etc. in the molten steel and slag, increasing the porosity, and slag enters the pores, causing bone phase. The main cause is the reaction with MgO or the wear due to the floating of bone phase. This loss is caused by the F content in the slag because slag-forming agents are not used extensively in slagless or minimum slag operation of converters.
ed, the ratio of components such as MnO that oxidizes carbonaceous substances in bricks becomes extremely high, and the process progresses rapidly. In addition, in the case of high-temperature operation such as stainless steel, the reaction between carbon and carbon (MgO x Mgj x C○↑
), the wear and tear of bricks progresses rapidly.

As a result of a detailed study of the two causes of wear and tear in magnesia and carbon bricks, the inventors found that
When metal magnesium powder is added to carhon brick,
When the temperature of the brick exceeds about 1,100°C during use, the added makufusoum vaporizes and becomes vapor, which diffuses through the pores to the operating surface. It was discovered that FeO, MnO, etc. in the slag oxidizes to MgO, which is deposited in the pores of the working surface of the brick. A secondary Pericles layer is formed on the outside of the brick to prevent slag from entering the inside of the brick, and on the inside of the brick it suppresses the reaction between magnesia and carphone by increasing the internal pressure. It does the work. It has been found that this will reduce the wear and tear of makufusia/carhon bricks, and will dramatically increase the number of surface/j uses.

However, the formation of the above-mentioned secondary Pericles layer does not occur simply by adding metallic magnesium powder to ordinary makushia carbon fiber; the dense secondary Pericles layer is formed only under special conditions. It has been found that the present invention has been completed. The formation of this secondary Pericles layer is affected by impurities in the graphite and magnesia clinker, especially the 5102 component, and if the SiO2 component is large, it will react with MgO to produce a low melting point substance, which will flow out into the slag. The secondary Pericles layer is not generated. Almost half of the ash content in graphite (is SiO2, so the fixed carbon content in black ↑1) is 97% by weight or more, preferably 9% by weight.
85% or more. Furthermore, the reason why graphite scales are used is to suppress the reaction between the carbon and the carbon as much as possible. On the other hand, in terms of its impurity composition, Maknenak linker also contains over 96% MgO.
It is preferably 98% by weight or more. MgO
If the content is less than 96% by weight, it will easily react with basic slag, leading to severe erosion of the magnesia bone phase, resulting in a stable secondary
This results in melting and loss before the crickle layer is formed. Further, it is preferable that the size of the Vericles crystals in the clinker be as large as possible. If the above conditions are satisfied, the secondary Pericles layer is sufficiently formed. The ratio of magnesia clinker and high-purity graphite used is within the range used for ordinary makushia carbon bricks, with magnesia clinker being 50 to 90% by weight, preferably 60% by weight.
~85% by weight, the balance being high purity graphite.

The metallic magnesium powder used in the present invention has a series of characteristics such as 98% purity by weight or more in terms of impurities, and an average particle size of 20-200 mesh, preferably 40-200 mesh.
If the required particle size is larger than 20 mesh, the remaining pores after turning into steam will be large, causing problems in terms of strength and durability. It is dangerous to handle and also reacts too quickly, which is undesirable. The amount of this 10,000 gold magnesium is 0.5 to 10% by weight, preferably 2 to 10% by weight based on the total amount of red sea bream, shea clinker and scale graphite.
6% by weight is suitable. If the amount used is less than 0.5% by weight, the amount added is too small to form a sufficient secondary Pericles layer, and if it is more than 10% by weight, the strength is significantly reduced.

In this way, the durability of the magnesia-carbon brick of the present invention is dramatically improved by preventing oxidation of the carbonaceous material and preventing erosion of the magnesia clinker by the secondary Pericles layer generated by the vaporization, diffusion, and reaction of magnesium metal. However, when the amount of metallic magnesium used is close to the upper limit in order to make the effect of forming the secondary Pericles layer more effective, the number of gl′, Ru.

This phenomenon gradually becomes a problem when the durability of the brick is improved by the present invention and the one-cycle usage time becomes longer. The second feature of the present invention is that metallic aluminum powder is added together with metallic magnesium into the brick in order to prevent damage such as a decrease in strength due to the increase in pores.

Metallic aluminum added together with metallic magnesium gradually reacts with carbonaceous matter at high temperatures during use of the bricks to form aluminum carbide, and the volumetric expansion at that time blocks the pores created by vaporization and diffusion of magnesium in the bricks. This prevents deterioration. In addition, metal aluminum reduces C○ produced by oxidation of carbonaceous matter, and prevents the loss of carbonaceous matter. At the same time, it becomes an oxide, reacts with fine powder of magnesia clinker, and becomes spinel, which expands its volume, strengthens its bond, and It plays a role in reducing the carphone reaction.

In this way, the addition of metallic aluminum plays a role in supporting the effects of metallic magnesium. In terms of reactivity and reaction rate, among the various metals, only aluminum can exhibit its effects when used in combination with metallic magnesium. The average particle size of the metallic aluminum used is preferably 200 metric tons or less; if it is larger than this, the reaction rate is slow and the pores from which metallic magnesium has escaped cannot be sufficiently closed. The amount used is 01 to 10 parts by weight, preferably 04 to 6 parts by weight.
In parts by weight, the ratio to magnesium is At/Mg='0.2-1 on a weight basis. This ratio is 0
If it is less than 2, the supporting effect for magnesium is not sufficient, and on the contrary, even if it increases to more than 1, the effect remains unchanged.

tS O 1 If there is a large amount of metal red sea bream or sea bream, use A.
It is desirable to use metallic aluminum so that the ratio of 1/Mg is large, and when the historical amount of metallic magnesium is small, the ratio of AI/Mg is small.

When magnesium metal and aluminum metal are used together, their respective powders may be mixed and used, or an alloy powder of magnesium and aluminum may be used.

The manufacturing method of magnesia carphone bricks according to the present invention is the same as the conventional method, and the raw materials are blended in particle size, and after mixing, one or two or more types are selected from various organic resins such as pinch, tar, and phenolic resin. (11) can be used as an unfired product that is added and kneaded and then heat treated at a low temperature after molding or a fired product that is heat treated in a high temperature reducing atmosphere.

As described above, the present invention involves adding metallic magneum powder to carbon-bonded magnesia bricks, and by vaporizing and oxidizing the powder, a dense secondary Pericles layer is formed near the working surface of the brick. In addition, metallic aluminum powder is added to block the pores created by the movement of metallic magnesium due to expansion of the structure due to reaction with carbon 7-1. This prevents the deterioration of the river and dramatically increases the river.

The present invention will be specifically illustrated by examples below.

Examples 1 to 4 Sintered magnesia clinker with Mg0 content of 985% by weight
20% by weight of scaly graphite with 80% by weight and 99% by weight of fixed carbon.
The mixture was molded into the shape of a cap-shaped brick in the proportions shown in Table 1, heat-treated at 300° C. for 4 hours, and the brick was examined. For this brick, the converter slag was heated to 1700°C15 using FeO-enriched slag.
A slag test was conducted at 1780° C. for 5 hours. The results are shown in Table 1.

Example 5 Magne/Aclinker - 70% by weight, scaly graphite 30% by weight
The procedure was carried out in the same manner as in Example 1 except that 6 parts by weight of metallic magnesium was added, and the results shown in Table 1 were obtained.

Comparative Examples 1 to 4 The same procedure as in Example 1 was carried out by changing the purity of magnesia clinker and graphite scales and the added metals.

Note that the corrosion resistance index in Table 1 was determined from the following formula.

As is clear from the results in Table 1, in the bricks to which the metal magneto/lamb powder of the present invention was added, the secondary Helicles layer was completely formed, and the FeO content in the slag was increased and the test temperature was high. As the conditions become more severe, the superiority of the corrosion resistance of the noodles becomes clear; it is about three times as strong as those without metal salts, and about twice as strong as those that add aluminum metal instead of magnesium metal. It shows corrosion resistance of 1 grade.

Example 6 Using the same bricks as in Example 2, a slag test was conducted under the conditions of Example 2 over a period of 111 hours, which is three times as long as the test time, which is 15 hours. Table 2 shows the results.

Examples 7 to 9 Bricks having the compositions shown in Table 2 were subjected to a slag test under the same conditions as in Example 6, and the results are shown in Table 2.

Comparative Examples 5-6 Example 6 using bricks with the compositions shown in Comparative Examples 2 and 4
A slag test was conducted under the same conditions.

The results are also shown in Table 2.

Table 2: Miζ (partly present in the 1780°C slag test) According to the results in Table 2, are the metal machinium additives superior in corrosion resistance compared to the metal aluminum additives? If it extends to
(see table).

This is thought to be due to the effect of the number of species of magnesium powder in the long-term slag test. However, it can be seen that when metallic magnesium and metallic aluminum are used together, the decrease in corrosion resistance can be suppressed. In other words, the effect of the combined use of metal aluminum is appearing.

Patent Applicant: Kyushu Fire Brick Co., Ltd. Procedure Nelt Official Book November 1983 Cod Day 1, Indication of Case 1983 Patent Application No. 83291 2, Name of Invention Magnesia Carbon Brick 3, Person Making Amendment Case and Relationship between Patent Applicant 4, date of amendment order In-house As per attached sheet (no change in content other than the matters stated in the column subject to amendment) Contents of amendment 1 Page 8 of the specification, lines 9 and 11 “ Correct ``1'' to ``2''.

Indication of Procedural Amendment 16 Case 1983 Patent Application No. 83291 2, Title of invention: Magnesia Carbon Brick 3, Relationship with the case of the person making the amendment Patent applicant Address: 1175-5 Uraybe, Bizen City, Okayama Prefecture, Amendment Scope of Claims column and Detailed Description of the Invention column 6 of the subject specification, contents of the amendment As per the previous paper (contents of the amendment stated in the column of subject of the amendment 1. "Scope of Claims" column) will be corrected as shown in the attached sheet.

2. Correct "97" to "95" on page 2, line 4 of the specification section, and page 5, line 1.

Attachment Claims (1) For 100 parts by weight of a mixture of magnesia clinker with an MgO content of 96% by weight or more - 50 to 90% by weight and fixed carbon - scaly graphite with a Kamej weight% or more of 50 to 10% by weight, the average particle A carbon-bonded magnesia-carbon brick having a diameter of 20 to 200 mesh and containing 0.5 to 10 parts by weight of metallic magnesium powder having a purity of 98% by weight or more.

(2) For 100 parts by weight of a mixture of 50-90% by weight of magnesia clinker with an MgO content of 96% or more and 50-10% by weight of scaly graphite with a fixed carbon content of 95% or more, the average particle size is 20-200 mesosi. 0.5 to 10 parts by weight of metallic magnesium powder of 98% by weight or more and an average particle size of 20
A carbon-bonded magnesia-carbon brick, characterized in that 0.1 to 10 parts by weight of metallic aluminum powder of 0 mesosinus or less is added.

Procedural amendment 1981 5/& Mr. Commissioner of the Japan Patent Office 1, Indication of the case 1983 Patent Application No. 83291 2, Title of invention: Magnesia carbon brick 3, Person making the amendment Relationship to the case Patent applicant Address: 1175 Uraybe, Bizen City, Okayama Prefecture
Name: Kyushu Fire Brick Co., Ltd. Representative Takuji Shioda 4; Date of amendment order: Vol. 5; Column 6: Detailed explanation of the invention in the specification subject to the amendment; Contents of the amendment (as stated in the attached sheet) (No changes to the content other than the above.) Amendment details 1, page 5, line 17 of the specification: ``60-85J is amended to ``70-90''.

Claims (1)

[Scope of Claims] (11 N to 100 parts by weight of a mixture of 50 to 90% by weight of magnesia clinker with an MgO content of 96% or more and 50 to 10% by weight of scaly graphite with a fixed carbon content of 97% or more,
A carbon-bonded magnesia-carbon brick characterized by adding 0.5 to 10 parts by weight of metallic magnesium powder having an average particle size of 20 to 200 mesh and a purity of 98% or higher. (2) For 100 parts by weight of a mixture of 50 to 90% by weight of magnesia clinker with an MgO content of 96% or more and 50 to 10% by weight of scaly graphite with a fixed carbon content of 97% or more,
0.5 to 10 parts by weight of metallic magnesium powder with an average particle diameter of 20 to 200 mesh and a purity of 98% by weight or more and metallic aluminum powder 01 to 1 with an average particle diameter of 200 mesh or less
A carbon-bonded magnesia carbon brick characterized in that 0 part by weight is added thereto.