JPH0365569A - Repairing material for hot gunning - Google Patents

Abstract

PURPOSE:To obtain a repairing material for hot gunning with increased hot adhesion strength and hot strength by adding a Ca alloy containing Mg or Si to a refractory composition containing aggregate comprising magnesia clinker or dolomite clinker. CONSTITUTION:A refractory composition is prepared by adding a binder, a setting agent and other additives to an aggregate mainly consisting of magnesia clinker or dolomite clinker. 100 pts.wt. of the refractory composition are combined with 0.5 to 10 pts.wt. of a Ca alloy powder containing at least one selected from Ma and Si. The addition of the Ca alloy exerts not only the effect of increasing hot adhesion and hot strength but also the effect of preventing the oxidation of the carbon bonds, while the addition of a carbonaceous binder can reveal the effect of slag resistance and spalling resistance at maximum. The amount of the carbonaceous cobinder used is preferably 3 to 10 pts.wt. based on 100 pts.wt. of the refractory composition, and less than 3 pts.wt. does not satisfy the slag resistance, while more than 10 pts.wt. results in the deterioration in the processed products, adhesion strength and corrosion resistance.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention is a method for hot spraying repair of linings of molten metal containers such as various steelmaking furnaces, which have excellent hot strength, hot adhesion, and durability. Regarding fire resistance ÷ 4 materials.

[Conventional technology]

In recent years, large copper materials used for lining converters, secondary refining furnaces, etc., have become more durable due to the harsher steelmaking conditions, such as high-purity magnesia or fused magnesia. This has been dealt with by using expensive refractories. In order to prevent melting of the refractory lining, we maintain a balance as a whole by repairing the melted parts using hot-sprayed refractory material, thereby extending the life of the refractory.

However, the durability of the large spray-resistant material used is insufficient, and efforts have been made to develop highly durable spray repair materials that enable stable operation of the furnace.

For example, in the magnesia dolomite system, which has been mainly used as a hot spray repair material for converters, sodium phosphate is blended as a binder, as described in Japanese Patent Publication No. 55-6598. Electrical resistance can be improved by optimizing the type and location.

Attempts have been made to improve the adhesion, etc., but Rh (Rh) has not shown sufficient ml usability under industrial conditions.

In addition, on the side of carbon bond spraying, it is necessary to coat the refractory aggregate with bitch, resin, etc. in order to eliminate the disadvantages of carbon sources such as bisochi, tar, etc., which have poor M attachment and I contact properties. was proposed in Japanese Patent Publication No. 56-26777, and Japanese Patent Publication No. 61-35152 proposed the use of a pellet containing pitch, tar, etc. in a hollow capsule to improve durability. All of them have problems such as insufficient effectiveness or difficulty in practical use.

[Problem to be solved by the invention]

The problem to be solved by the present invention is to eliminate the drawbacks of the above-mentioned conventional hot spray repair materials. The purpose of hot spraying is to provide a repair material with sufficient durability.

[Means to solve the problem]

The present invention is based on the knowledge that addition of alloy powder containing Ca is effective in improving the hot adhesion of repair materials in hot spraying mainly made of magnesia and dolomite, resulting in high hot bond strength and high hot strength. Completed based on.

That is, the hot spray repair material of the present invention is a basic refractory material mainly composed of magneur or dolomite clinker.
M
31, or 0.5 to 10 parts by weight of Ca alloy powder containing either of these components.

[Effect]

The Ca alloy powder added to the refractory material melts inside the object after being sprayed between parts, and acts as a binder when it is oxidized in the recesses on the surface of the object or inside the material to be sprayed. Improves adhesive strength and hot strength.

In addition to the above-mentioned effects, in the case of a so-called silica-based spray material that uses a carbon source in combination, hot adhesion and hot strength are also improved due to the reaction of the alloy with C to produce highly refractory carbide.

Furthermore, in the case of an alloy containing a metal element with a strong affinity for oxygen, the oxidation resistance of the sprayed material is also improved. Metal elements that are relatively easy to handle and have strong oxygen affinity include AI, Ca,
Mg, Si, etc. are considered, but when added to a material mainly composed of dolomite, metals or alloys containing AI are
After l is oxidized, Ca is removed by reaction with CaO in the aggregate.
O・Aj! 20a・2 S i Oa (+n, I]
, 1550°C) or Na2O and Na in the binder,
○・AfzOz・6si○2 (m.

p, 1100°C), which significantly deteriorates fire resistance. For this reason, Al
Alternatively, the addition of an alloy containing Af is unsuitable for use because it actually causes deterioration in durability.

Furthermore, although the addition of Si is effective in improving hot strength by forming refractories such as SiC, oxidized S10. may be a factor in deteriorating the corrosion resistance of basic materials, and alone has little contribution to improving adhesion.

Mg melts and oxidizes quickly, and oxides pose no problem for basic materials, but they lack stability due to large evaporation.

On the other hand, Ca melts and oxidizes the fastest, and oxides not only improve adhesive strength but also improve corrosion resistance and Na2Cas (
It also contributes to the improvement of hot strength by producing a highly refractory composition such as P○*)2sioz (m, p, 1735° C.).

This highly refractory composition is made of condensed sodium phosphate P20s, NaaO, which is used as a binder during spraying.
It is thought that this is generated from the added alloys Ca and Si, but the formation of slag can be confirmed by X-ray analysis of the sample after hot bending strength measurement.

Furthermore, Ca-based alloys exhibit properties equivalent to /l-based alloys in terms of oxidation resistance of the carbon source in the material.

For this reason, alloy additives for improving the hot adhesion and hot strength of sprayed materials using dolomite, as well as for improving corrosion resistance, should be selected from two or more of Ca, Mg, and Si. A system containing Ca is effective. In this case, the amount of Ca in the alloy is preferably 10% by weight or more, and if it is less than that, sufficient hot adhesion cannot be obtained.

In addition, if the amount of alloy added to the refractory is less than 0.5 parts by weight per 100 parts by weight of the refractory, the effect of adding the alloy on adhesive properties etc. will not be sufficient, and if it is more than 10 parts by weight, it will be difficult to spray water. The hydration reaction generates a large amount of gas, leading to deterioration of the construction structure.

The basic aggregates used in the present invention include magnesia clinker, and the dolomite clinkers include natural magnesia clinker-1, seawater magnesia clinker, M-melted magnesia clinker-7, natural magnesia clinker-7, natural magnesia clinker-1, and magnesia clinker-9. 1 or those whose surfaces are carbonated or coated with pitch resin, etc.
Two and ga ° (,8 can be.

In addition, it is preferable that the particle size of these basic frameworks be adjusted in consideration of the workability of blowing, the two-body structure, etc.

As a binder, phosphate, silicate, alumina cement,
Portland cement etc. can be used.

Other additives include workability 1), and various clays, evaporated silica, slaked lime, calcium carbonate, magnesium carbonate, or various organic fibers and inorganic fibers can be added as binding aids in the required amounts as necessary. .

Further, as additives as carbon-based auxiliary binders for forming carbon bonds, various types of tar pitch, mesopause carbon, thuunol resin, furan resin, crurfuryl alcohol resin, etc. can be used.

Particular features of the present invention - The addition of a certain amount of Ca-based alloy not only improves hot adhesion and hot strength, but also has a great effect of preventing carbon bond from oxidation. Maximizes infiltration, durability, etc.

The amount of the carbon-based auxiliary binder added is preferably 3 to 10 parts by weight per 100 parts by weight of the refractory; if it is less than 3 parts by weight, the slag infiltration resistance performance is insufficient, and if it is more than 10 parts by weight. Now, reverse 1. ″´This results in deterioration of the structure of the construction body, adhesive strength, and corrosion resistance.

〔Example〕

Refractory aggregate consisting of seawater magnesia clinker and synthetic dolomite clinker, with particle size adjusted to coarse, medium, and fine particles.To the heavy weight part, 4 parts by weight of phosphate binder and 4 parts of slaked lime as a hardening agent. Ca, Si, Mg in a coulometric ratio of Ca:S to a composition consisting of parts by weight.
i:Mg is 2:4. A Ca-31-Mg alloy powder of 1,200 mesh or less consisting of +3 was added in the amount shown in Table 1 and used as a test material.

Ta. Note that the weight ratio of Al and Mg is A j! : M
Aj of less than 1200 mesh with g of 1:1! -M
g alloy powder was used for comparison17.

Each of the test materials was sprayed onto magnesia dolomite bricks in a large experimental furnace, and after curing for 15 minutes, the adhesive shear strength was measured. In addition, to measure the hot bending strength, the test material was cast in a 20 x 20
This was done after heating at 450°C for 3 hours.

Corrosion resistance, slag infiltration resistance, and oxidation resistance were evaluated using a high-frequency induction furnace lining test method at 1700° C. for 5 hours.

Table 1 shows the composition of the test pieces and the test results.

As the amount of Ca-3i-Mg alloy added increases, the hot bonding strength and hot bending strength change. As the amount of alloy added increases, the amount of high melting point minerals produced increases, and this is thought to contribute significantly to the improvement of hot properties.The effect is sufficient at an addition amount of 063 parts by weight, and 15 parts by weight. On the contrary, Ca
It can be seen that the appropriate addition amount of the -3i-Mg alloy is in the range of 0.5 to 10 parts by weight, with 4 parts by weight being particularly preferred.

Furthermore, the addition of An-Mg alloy shows a tendency for each hot characteristic to deteriorate as the amount added increases, indicating that addition to dolomite-based materials is inappropriate. This can be similarly determined from the results of the corrosion resistance test shown in the lower part of the table.

Table 2 shows the results of a study on a pitch-added system based on magnesia-dolomite aggregate.

Fish Nos. 10 to 15 were prepared by adding Ca-31-Mg to the same base material as in Example 1 with the pitch fixed at 7 layers and 1 part.
The influence of the amount of alloy added is examined, and from the perspective of each hot property, the appropriate amount of addition is 0.5 to 10 parts by weight.

In addition, it was also confirmed that in pitch-added alloys, the oxidation resistance improved as the weight of Ca-S1-Mg alloy added increased.

K 16 to 19 are studies on the appropriate value of the addition amount of bitge, and the effects of hot strength and oxidation resistance are insufficient in the double layer part, and the deterioration of corrosion resistance is large at 15 parts by weight.
The appropriate amount of pitch is determined to be 3 to 10 parts by weight.

Figure 1 shows CaS1- in samples Nα1 to 5 in Table 1.
Addition amount of Mg alloy and Na2Ca+(P 04)2Si
○, shows the relationship between the X-ray peak heights, and the second
The figure shows the relationship between the X-ray peak height and hot bending strength of the same sample. From these results, it was found that the amount of this mineral produced increases with the amount of Ca-3i-Mg alloy added, thereby improving hot physical properties.

(Hereinafter, the margin of this page) [Effects of the Invention] The hot spraying of the present invention can provide high performance not found in conventional materials by using the refractory material.

(1) It is possible to improve hot adhesion, hot strength, and oxidation resistance and corrosion resistance of carbon-based materials.

(2) As a result, it was possible to form a highly durable sprayed construction body that was not available with conventional materials, and it became possible to significantly extend the life of steelmaking furnaces.

[Brief explanation of drawings]

The attached FIGS. 1 and 2 illustrate the characteristics of the present invention.

Claims (2)

[Claims] 1. Ca alloy powder containing at least one of Mg and Si is added to 100 parts by weight of a fireproof composition made by blending aggregates mainly composed of magnesia clinker and dolomite clinker with a binder, a hardening agent, and other additives. A hot spray repair material containing 0.5 to 10 parts by weight. 2. 2. The hot spray repair material according to claim 1, further comprising 3 to 10 parts by weight of a carbon-based auxiliary binder as another additive.