KR900008589B1 - Refractory - Google Patents

Abstract

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Description

Refractory material for blast furnace

1 is a graph showing the relationship between molding pressure and filling density.

The present invention relates to a blast-furnace line fire retardant, in particular, a molten iron fire retardant having excellent heat corrosion resistance and abrasion resistance as well as good thermal shock resistance.

The blast furnace can be divided into large barrel, molten iron cylinder, and slag barrel according to its use, and conventional molten iron barrel (hereinafter referred to as "tongtong") is made of leadstone and chamotte as the main raw material. tar) trained material is mainly used. However, under severe conditions such as the increase in the number of draw times and the extension of the draw time due to the recent increase in the size of the blast furnace, and the degreasing treatment in the column, the material quality is significantly lower in hot corrosion resistance and abrasion resistance, and furthermore, expansion at high temperatures In severe use, such cracking caused peeling damage and shortened life.

As a way to solve this problem, by reducing the content of low erosion-resistant feldspar and chamotte, and by adding erosion-resistant aggregates, such as mullite (alulite) or alumina or silicon carbide (SiC) to improve the quality of the quality come.

However, these aggregates have improved defects in corrosion resistance and hot wear as the amount of the additives increases, but they are economically unsuitable due to their high price.

Accordingly, the present invention is to provide a blast furnace common refractory material that can be manufactured economically as well as excellent in erosion resistance, abrasion resistance and thermal shock resistance by hot MgO as a main component and adding a sintering agent to it. If this is described in detail as follows.

That is, the present invention is clay: 10-22% by weight, graphite powder, 4-7% by weight, pottery: 15-22% by weight, relative to 100% by weight of the magnesia source containing at least 50% by weight MgO, and Silica flour: It is related with the blast furnace fireproof material manufactured by kneading an inorganic binder with the raw material which mix | blended 7-15 weight%.

As the magnesia source, artificial raw materials such as raw ore, such as natural magnesite, gammonite and serpentine, and seawater magnesia clinker having a high content of MgO and magnesia clinker with high content of MgO, may be used. Preferred at

In addition, in general, since the workability is greater in various properties than other materials, the particle size distribution of the magnesia source is 10-5 mm particles: 6% or more, 5-3 mm particles: 30- 35%, 3-1 mm particles: 20-30% and 1 mm or less particles: 30-40% is preferred.

The inorganic binder plays a role of increasing plasticity (fillability) at room temperature. Examples of the inorganic binder include molasses, PVA, sodium silicate and sodium alginate, and CMC (Carboxyl Methyl Cellulose).

Hereinafter, the reason for numerical limitation of the said component is demonstrated.

The clay is used to give plasticity at the time of construction because it is constructed with air rammer, and if the amount is 10 wt% or less with respect to 100% by weight of magnesia, the plasticity is not properly given. Filling, that is, all the physical properties are lowered, and if the 22% by weight or more, the workability and dry strength is good, but not only severe shrinkage but also causes cracks during heating and heating is preferably 10-22% by weight.

The graphite powder has a buffering effect of expansion contraction and at the same time gives a softening inhibitory effect of the tissue due to the penetration of molten iron slag, when the blending ratio is less than 4% by weight relative to 100% by weight of the magnesia source Less buffering effect, less penetration inhibition effect of molten iron and slag, and in the case of more than 7% by weight, kneading is poor, not only inhibits sinterability, but also poor workability, 4-7% by weight is preferable. .

Coke powder may be used as the graphite powder.

The ceramic and silica flower is a component that is added to promote sintering at a temperature range around 1,400 ° C., which is the use temperature of the general material, because the basic refractory material has a high melting point and poor sinterability at high temperatures. If it is 15 wt% or less with respect to 100 wt%, the amount of low melting point material is low and sintering is hardly progressed, and thus the heat shock resistance, which is a drawback of strength and basic refractory material, is lowered. Since it is oversintered and the corrosion resistance falls remarkably, 15-22 weight% is preferable.

In addition, since the silica flower has a small specific gravity and a large volume, it is large in quantity even when a small amount is added, and at high temperature, the silica flower has a similar behavior, but when the added amount is 15% by weight or more, the sintering property is good, but the shrinkage is severe and erosion resistance Since this remarkably falls, 15% by weight or less is preferable.

On the other hand, the method of kneading the blended raw material by adding an inorganic binder such as molasses is preferably kneaded sufficiently by applying a magnesia source first, then again coated with graphite powder and then adding a clay and a sintering agent.

When molding the blast furnace refractory material of the present invention, as shown in FIG. 1 showing the packing density according to the molding pressure, the molding pressure is 100Kg / cm 2 or more, preferably 150Kg / cm 2 or more. Hereinafter, the present invention will be described in detail through examples.

EXAMPLE

In the composition ratio as shown in Table 1, natural magnesia clinker was applied with molasses solution, and then double-coated with graphite powder as a carbon source, and then clay as a plastic material and pottery and silica flower as a sintering material were added. A sufficiently kneaded material was molded to prepare a molded article, and hot bending strength, erosion resistance, and thermal shock resistance of the molded article were measured and shown in Table 2 below.

TABLE 1

TABLE 2

The hot bending strength of the molded product shown in Table 2 was measured at 1450 ° C, and the erosion resistance was melted at 1450 ° C in an induction furnace for 30 minutes, and then the remaining dimension was the erosion index when the erosion rate of the conventional material was 100. The thermal shock resistance is shown by measuring the number of times the surface crack (crack) is generated by repeatedly testing the air-cooled operation after holding for 30 minutes at 1300 ℃.

As shown in Table 2, the present invention can be seen that the physical properties of the refractory material, that is, the hot bending strength, erosion resistance and thermal shock resistance is superior to the conventional material.

As described above, the present invention has a basic refractory material as a main raw material, and a sintering agent is added thereto to improve the sintering property, thereby improving the erosion resistance and abrasion resistance in hot as compared with conventional materials, and also have an economically manufacturable effect. .

Claims (1)

Clay: 10-22% by weight, graphite powder: 4-7%, pottery: 15-22%, and silica flower: 7-15% by weight, based on 100% by weight of the magnesia source containing at least 50% by weight of MgO. Refractory material for blast furnace blast furnace characterized in that it is prepared by adding and kneading the inorganic binder to the raw material blended with.

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