KR100481883B1 - PHOSPHATE COMBINED MONOLITHIC REFRACTORIES UTILIZED SPENT Mg-Cr BRICK - Google Patents

Abstract

The present invention relates to a phosphate-bonded amorphous refractory material using waste magnesia lead. In the present invention, 45-50% by weight of waste magcro lead and ground powder having a particle size of 1-5 mm and a magnesia clinker having a purity of 98% or more are used. -35% by weight, 5-10% by weight of alumina powder, 3-6% by weight of alumina cement, 3-6% by weight of hexametaphosphate, and calcium carbonate in a weight ratio of 1: 1 based on the amount of hexametaphosphate used By manufacturing phosphate-bonded amorphous refractory materials, recycling large amounts of waste macrowax to refractory aggregates can reduce the cost of disposal and increase the utilization of resources. By using a much larger amount than the amount used as the dispersant in the amorphous refractory to produce an amorphous refractory to which the phosphate is bound, there is an effect of increasing the strength.

Description

Phosphate COMBINED MONOLITHIC REFRACTORIES UTILIZED SPENT Mg-Cr BRICK}

The present invention relates to a phosphate-bonded amorphous refractory using waste Magro lead, and more specifically, to a waste made by crushing a refractory brick used as a built-in refractory such as RH (Ruh: Ruhrstahl Hereaus, RH) equipment It is related to phosphate-bonded amorphous refractory materials prepared by recycling magnesium lead and pulverized product to 50% by weight or less and using magnesia clinker aggregate, alumina powder, alumina cement, calcium carbonate and sodium hexamethaphosphate.

In general, the steelmaking process includes magnesia (MgO) -based lead, magnesia-carbon (MgO-C) -based lead, magnesia-chromium (MgO-Cr ₂ O ₃ ) -based lead as internal refractories such as converters, ladles, and RH facilities. Use refractory Among them, magnesia-chromium lead is a brick manufactured by mixing chromium ore with magnesia clinker to compensate for the defects of magnesia lead and chrome lead. It is usually referred to as magcro lead) and less than 50% is distinguished from chromium-magnesia lead (usually called chromag lead).

Magcro lead is used for RH facilities in steelmaking process, vacuum oxygen decarburization (VOD) ladles, lime kilns, rotary kilns for cement processes, etc. Since it needs to be replaced with croissant, a large amount of waste macrocrops are generated during the replacement process. Most of the waste makrowawa landfill is disposed of in landfill, which has a problem of environmental pollution and landfill has a limit. Therefore, the recycling of the waste Magro lead is required, and in particular, if the waste Magro lead can be recycled to the original use of the refractory, it is more preferable in that the manufacturing cost of the high refractory can be lowered.

The present inventor has disclosed in Korean Application No. 95-28915 an amorphous refractory of a basic dam block for tundish prepared using magnesia clinker, alumina cement, hexametaphosphate and calcium carbonate. However, only magnesia clinker was used here as the main raw material, and no lung muffler was used.

In addition, Japanese Patent Application Laid-Open No. 62-148354 discloses a basic inflow molding material prepared by using magnesia as a refractory aggregate and adding alumina fine powder, alumina cement and aluminum tripolyphosphate. However, there is no recycling of used methane with waste magnesia instead of magnesia.

SUMMARY OF THE INVENTION The present invention has been made to solve the above problems, and its purpose is to recycle waste Magcro lead generated in large quantities into refractory aggregates of amorphous refractory materials, reducing the cost of disposal and at the same time utilizing the resources. It is to provide a phosphate-binding amorphous refractory using waste Magro yeonwawa to increase the effect.

In order to achieve the above object, in the present invention, 45-50% by weight of waste magcro lead and ground product having a particle size of 1-5 mm, 28-35% by weight of magnesia clinker having a purity of 98% or more, and alumina powder 5-10% by weight of alumina cement, 3-6% by weight of alumina cement, 3-6% by weight of hexametaphosphate, calcium carbonate in a weight ratio of 1: 1 to the amount of hexametaphosphate used, Manufacture.

At this time, the magnesia clinker is preferably used by mixing the one passed through a 1 mm sieve and the 0.074 mm sieve.

Hereinafter, the phosphate-bonded amorphous refractory material using waste magnesia lead according to the present invention will be described in detail.

Although the slag or the like impurities are attached to the movable part of the waste magnet produced by the RH facility of the steelmaking process and are slightly deteriorated by thermal action, it is a state which can be used sufficiently as a refractory aggregate. In other words, the increase in the content of slag components, specifically SiO ₂ , Fe ₂ O ₃ , CaO, etc. in the moving part of the remaining yeonwawa when dismantling the furnace wall was confirmed that there is no significant difference with the yeonwa before use such a waste Magro yeonwa It can be pulverized and used for refractory aggregates of amorphous refractory materials such as castables or indents.

In the present invention, a part of the magnesia clinker used as the refractory aggregate is used in place of a pulverized product with waste magnesia. Waste Magcro lead and grind have a particle size of 1-5 mm and use 45-50% by weight of the total refractory. If the use amount of the waste macro lead and pulverized in excess of 50% by weight is to reduce the corrosion resistance and workability is to limit the amount to 50% by weight or less.

The magnesia clinker has a purity of 98% or more and is used at 28-35% by weight, with the addition amount being passed through a sieve through which sieves with a particle size of less than 1 mm are filtered and through a sieve with particles with a particle size of 0.074 mm or less. Use separately.

As a by-product, 5-10% by weight of alumina powder, 3-6% by weight of alumina cement, 3-6% by weight of calcium carbonate, and 3-6% by weight of hexametaphosphate, wherein calcium carbonate and hexamethic acid Soda makes the addition amount the same, that is, the ratio of 1: 1.

The amount of magnesia clinker used is determined by excluding the amount of waste magnesia lead, crushed powder and by-products, and the result is 28-35 wt% of the amount of magnesia clinker mentioned above.

As the alumina powder, an ultrafine powder having a particle size of 5 µm or less is used. The use of ultra-fine alumina improves fluidity when used as castables, and reacts with magnesia when used in the heat to form MgO · Al ₂ O ₃ spinels, and inhibits infiltration of molten steel or slag by the generated spinel. Strength is also enhanced. If the alumina powder is used in an amount less than 5% by weight, the hot strength is lowered. If the alumina powder is used in an amount of more than 10% by weight, an excessive amount of spinel may be generated, resulting in excessive expansion and decay. In addition, the refractory material in which an excess of spinel is produced loosens tissue, thereby reducing the effect of inhibiting slag infiltration. Thus, the preferred amount of alumina powder is 5-10% by weight.

Alumina cement acts as a curing agent and a binder, and alumina cement of 70% grade of alumina is usually used. If the addition amount of the alumina cement is less than 3% by weight, the function as a curing agent and a binder is weak, the curing time is long, and the drying strength is insufficient. When used in excess of 6% by weight, corrosion resistance and volume stability are lowered. Therefore, it is preferable to use 3-6% by weight of alumina cement.

Sodium hexametaphosphate uses commercially available commercial industrial powders, and imparts fluidity when used in castables and the like and expresses strength as a binder at room temperature and high temperature. When used in basic amorphous refractories, it acts as a curing agent for alumina cement and magnesia at low temperatures, improving dry strength, and reinforcing a decrease in strength of alumina cement at intermediate temperatures. In addition, at high temperatures, it reacts with the CaO component of calcium carbonate to produce Na ₂ O · 2CaO · P ₂ O ₅ , which is a stable substance at high temperatures, to impart hot strength. If the hexametaphosphate is used at less than 3% by weight, the water consumption is high and the curing proceeds too fast, making it difficult to install. Even when the block is manufactured, it is not suitable as a dam because cracks or warpage occur in the drying body when the dam block is dried. Dry strength is also low. On the other hand, the use of more than 6% by weight of hexametaphosphate decreases the hot and plastic strength and also the erosion resistance. Therefore, a suitable amount of sodium hexametaphosphate is 3-6% by weight.

Usually, hexamethaphosphate used in amorphous refractory serves only as a dispersant and its amount is about 0.1% by weight, but the present invention uses much higher amounts of 3-6% by weight. For this reason, it is one of the characteristics of the present invention to prepare an amorphous refractory to which phosphate is bound by forming Na ₂ O. ₂ CaO. P ₂ O ₅ which enhances the strength as mentioned above.

Calcium carbonate is added at a weight percent of 1: 1 with sodium hexametaphosphate. If the weight ratio of calcium carbonate to sodium hexametaphosphate is not 1: 1, that is, if the amount of calcium carbonate is less than the amount of sodium hexamethane phosphate, volatilization of sodium hexamethane phosphate occurs at high temperature, and the high temperature strength and plastic strength are high. Degrades. In addition, when the amount of added calcium carbonate is higher, excess calcium carbonate reacts with alumina to produce calcium aluminate-based (C12A7, CA) low melting point material, which adversely affects the properties of basic amorphous refractory materials.

Hereinafter, the phosphate-binding amorphous refractory material using the waste macropharo according to the present invention will be described in detail through examples.

Table 1 shows the composition (weight%) of Examples 1-3 of the present invention together with the compositions of Comparative Examples 1-10.

Example Comparative example One 2 3 One 2 3 4 5 6 7 8 9 10 Waste Magcro Lead And Grind 45 50 45 60 45 45 45 45 45 45 45 45 45 Magnesia Clinker (1mm) 15 10 15 0 15 15 15 15 15 15 15 15 15 * Magnesia Clinker (0.074mm) 18 18 20 18 22 13 21 16 16 17 20 15 18 * Alumina powder 7 7 7 7 3 12 7 7 7 7 7 7 7 Alumina cement 5 5 3 5 5 5 2 7 5 5 5 4 5 Hexametaphosphate 5 5 5 5 5 5 5 5 3 6 5 7 5 Calcium carbonate 5 5 5 5 5 5 5 5 5 5 3 7 5

* Indicates that the purity of magnesia clinker is 95%.

7.5% water was added to the castable blended with each raw material with the composition as shown in Table 1, and then kneaded, and the specimens were cured and dried to prepare refractory materials. Various physical properties of the refractory material prepared in this way were measured, among which hot strength was measured at a temperature of 1400 ° C. for specimens produced in the size of 40 × 40 × 160 mm. Erosion test was carried out by the rotary erosion test method, the slag generated in the ladle was used as the erosion agent, the erosion test temperature was 1650 ℃. The measurement results of the physical properties of the refractory prepared according to Examples 1-3 and Comparative Examples 1-8 shown in Table 1 are as Table 2 below.

Example Comparative example One 2 3 One 2 3 4 5 6 7 8 9 10 Dry bending strength 152 140 147 70 140 145 120 110 60 70 80 155 150 Plastic strength (1500 ℃ x 3 hours) 65 65 67 60 50 80 70 65 50 50 80 50 60 Hot strength (1400 ℃) 25 18 20 8 5 15 5 5 3 4 5 4 15 Hot linear expansion rate (%, 1000 ℃) 1.1 1.1 1.3 1.0 0.8 1.7 1.1 0.9 1.1 1.0 1.1 1.0 1.1 Erosion Index 95 75 80 130 70 80 80 120 70 75 100 110 100

As shown in Table 2, it was confirmed that the phosphate-bonded amorphous refractory material using the waste mcropatite according to Examples 1-3 of the present invention had excellent corrosion resistance and hot strength.

In contrast to the results of Examples 1-3, the results of Comparative Examples 1-8 are as follows.

In Comparative Example 1, excessive amounts of lead and pulverized powder were added to the waste magnes, and as a result, the strength was lowered and the erosion resistance to slag was lowered. This is considered to be due to the imbalance in the refractories of the refractories as the amount of waste magnesite lead and pulverized products increases, and the amount of slag adhering to the surface of the waste magnesite lead and pulverized products increases.

Comparative Examples 2 and 3 are cases where the addition amount of alumina powder is too small or too large in the castable composition, respectively, in the comparative example 2, the hot strength is lowered, and in the comparative example 3, the expansion ratio in the hot is high, which is a problem.

In Comparative Examples 4 and 5, respectively, the amount of alumina cement added was too small or too large. In Comparative Example 4, the dry strength was low. In Comparative Example 5, the hot strength was lowered due to excessive liquid production.

In Comparative Example 6-9, the amount of added hexamethaphosphate and the amount of added calcium carbonate were not the same or were excessively high, indicating that the hot strength was very low in all cases.

In Comparative Example 10, a magnesia clinker having a purity of 95% was used, and the hot strength was low.

From the results of Examples 1-3 and Comparative Examples 1-10 described above, the slag is used according to the present invention by using waste magcro lead and ground powder as aggregate, and otherwise using the same as used in conventional magnesia castables. The castable with excellent corrosion resistance and hot strength could be manufactured.

As described above, the present invention has the effect of reducing the cost of disposal and increasing the utilization of resources by recycling waste Magcro lead generated in a large amount into refractory aggregates of amorphous refractory materials.

In particular, in the present invention, by using a much larger amount of sodium hexametaphosphate than the amount usually used as a dispersant in the amorphous refractory, by producing a refractory-bonded amorphous refractory, there is an effect to enhance the strength.

Claims (2)

Magnesia clinker is a mixture of 45-50% by weight of waste Magcro lead and ground powder with a particle size of 1-5 mm, a purity of 98% or more, and a 1 mm sieve and a 0.074 mm sieve. 28-35% by weight, 5-10% by weight of alumina powder, 3-6% by weight of alumina cement, 3-6% by weight of hexamethic acid soda, 1: 1 ratio of calcium carbonate to hexametaphosphate usage Phosphate-bonded amorphous refractory prepared using magnesia clinker as a balance. delete