KR100221802B1 - A spray material - Google Patents

Abstract

The present invention relates to a spray material for a secondary refining furnace, to prevent peeling and dropping during use, to improve adhesion and dehydration with the base material, to improve the corrosion resistance and adhesion and hot strength, and to control the moisture during installation It is an object of the present invention to provide a spray material for a secondary refining furnace that is wide and has low water loss and is free from thermal explosion and peeling.

Spray material for secondary refining furnace according to the present invention for achieving the above object, particle size 2-1mm natural magnesia clinker 19-21wt%, particle size 1mm or less natural magnesia clinker 59-61wt%, fine granular natural magnesia clinker 14-16wt% Phosphoric acid-based 0.3-1.5 wt%, silicic acid-based 0.5-3.5 wt%, clay-based 0.5-3wt%, ultrafine silica powder 0.3-2wt%, and calcium-based 0.5-4wt% are added to the phosphorus raw material.

Therefore, there is an effect that can improve the quality of the steel while removing the influence of boron and phosphorus.

Description

Secondary Refinery Spray Material

The present invention relates to a spray material for a primary refining furnace, and more particularly to a spray material for a secondary boron of low boron and low phosphoric acid type used as a refractory mounting repair material for the secondary refining furnace of the steelmaking process.

In general, the secondary refining spray material should have good adhesion and hardenability with the base material, have high corrosion resistance, high adhesion, and high hot strength, and should have a wide range of moisture control and low water loss during installation. Should be without.

Conventionally, boron oxide (B ₂ O ₃ ) type and lead oxide (P ₂ O ₅ ) type have been added to the seawater magnesia clinker as a spray material for the secondary refining furnace.

However, the boron oxide-based supernatant exhibits a limitation in prolonging the service life by rapidly lowering the melting point of the seawater magnesia clinker used as the main raw material.

In addition, since the boron oxide is contained in the seawater magnesia clinker to increase the reactivity with the boron oxide added as a binder to lower the melting point, it is necessary to use a magnesia clinker having a less boron oxide content in the clinker than the seawater magnesia clinker.

On the other hand, the phosphorus (P) component of the lead oxide-based binder is combined with iron (Fe) to become iron phosphide (Fe ₃ P), thereby promoting the coarsening of the particles, while increasing the hardness and tensile strength, but reduces the elongation, The impact value at room temperature is reduced to cause cold shortness.

In addition, the iron phosphide (Fe ₃ P) is bonded to the manganese oxide (MnO) to form a ghost line (Ghost line), which not only causes the fracture, but also solidify easily segregation at the grain boundary, diffusion rate Even when heated at a high temperature, it is difficult to diffuse, and because it remains as a band structure, the impact value is reduced to become a center of rupture.

Moreover, the lead oxide-based phosphoric acid component added to the seawater magnesia clinker as a binder lowers the corrosion resistance of the refractory material and is incorporated into the steel to give brittleness.

The present invention has been made to solve the problems described above, in consideration of the effect of the boron (B) and phosphorus (P) on the quality of the steel, while reducing the amount used for this, it is possible to improve the quality of the steel As a high-solubility binder to magnesia clinker raw materials, by adding an appropriate amount of calcium-based, silicic acid-based, clay- and low-phosphate-based binders, the matrix part is reinforced to prevent peeling and dropping during use, and it is more difficult to disperse Improved adhesion and dehydration with the base metal by increasing the content of the system, improves corrosion resistance, adhesion and hot strength, wide moisture control when attached, less moisture loss, secondary refining without explosion and peeling It is an object to provide a spray material for a furnace.

Spray material for the secondary refining furnace according to the present invention for achieving the above object, particle size 2-1mm natural magnesia clinker 19-21wt%, particle size 1mm or less natural magnesia clinker 59-61wt%, fine natural magnesia clinker 14-16wt To the raw material of%, as a solid solution, 0.3-1.5 wt% of phosphoric acid, 0.5-3.5 wt% of silicic acid, 0.5-3 wt% of clay, 0.3-2 wt% of ultrafine silica powder, and 0.5-4 wt% of calcium-based were added. It features.

Hereinafter, preferred embodiments of the present invention will be described in detail.

Example 1

As shown in Table 1, in the raw material having a particle size of 2-1mm natural magnesia clinker 20wt%, particle size 1mm or less natural magnesia clinker 60wt%, fine (0.075mm or less) natural magnesia clinker 15wt%, the phosphoric acid content is reduced to a minimum 2.8wt% of silicic acid-based binder is added to improve the steel quality, and the spray material for secondary smelting furnace is manufactured, and the discharge pressure of 0.8-1kg / ㎠, GMP 1- 2, the amount of water (the actual water amount: 14-18wt%), a spray distance of 300mm, a spray amount of 50kg subjected to room temperature the pilot test, the hot pilot testing, MgO-Cr ₂ O ₃ on the injection brick in an electric furnace 800-1000 ℃ After the test, 16 wt% of water was added in a 45 mm mold to form a specimen, dried at 110 ° C., subjected to four erosion tests at 1600-1800 ° C. for 30 minutes, and 16 wt% of water was added to 300 g of sample for 1 minute. After kneading 3 , 5 minutes, every 30 minutes to perform a curing test, and the specimen was molded by adding 16wt% moisture in a 4 × 4 × 160mm mold mold, dried at 110 ℃, 2 hours at 1000 ℃ or 1400 ℃ in an electric furnace It was fired during the physical property test, and the results are shown in Table 2.

[Examples 2 to 3]

As shown in Table 1, 1 wt% of a phosphate binder was added to the same raw materials and particle sizes as in Example 1, and 3 wt% of the silicic acid binder was added in the case of Example 2, 3.5 wt% in the Example 3, and silicic acid was added. The spraying material was manufactured by changing the addition amount according to the characteristic difference of the type | system | group binder, and it tested by the method similar to Example 1.

When 1 wt% of phosphate binder was added, the viscosity of the spray material was increased to increase the hot adhesion and strength with the base material, and the addition of appropriate silicic acid binder showed excellent water controllability and dischargeability.

In the case of Example 2, as a result of increasing the content of the two types of silicic acid-based exhibiting high solubility characteristics compared to Example 3, the adhesion was excellent and the amount of added water was reduced.

As a result of these specimens being eroded specimens and rotating eroded at 1650 ℃ × 5 charges (30 minutes / charge) and slag C / S = 1, they have superior contents of about 10-15% compared to existing products (Comparative Example 1). Appeared.

Comparative Example 1

As shown in Table 1, in a mixed raw material consisting of 10 wt% of fine natural magnesia clinker, 20wt% of seawater magnesia clinker with particle size of 2-1mm, 30wt% of seawater magnesia clinker with particle size of 1mm or less, and 5wt% of seawater magnesia clinker of fine grain, as a binder 4.5 wt% of the silica, 0.5 wt% of the silica, 0.5 wt% of the clay, 8 wt% of the calcium type, and 3.5 wt% of the calcium type 2 were added to prepare a spray material for the secondary refining furnace. After the test, the results are shown in Table 2.

Comparative Example 2

Particle size 2-1mm natural magnesia clinker 20wt%, particle size 1mm or less natural magnesia clinker 60wt%, particulate natural magnesia clinker 15wt%, as a solid solution, 1.5wt% phosphate, 0.5wt% clay, ultrafine powder 1.0 The wt%, 4 wt% of calcium-based species, 1.5 wt% of two calcium-based compounds were added to prepare a spray material for the secondary refining furnace, and the results were shown in Table 2 after the same test as in Example.

When the ultrafine silica powder is added as the main binder without using the silicic acid-based binder, similar to Example 1, the water controllability and dischargeability are lowered, and the ultrafine silica powder is agglomerated at the end of the spray nozzle. This separation phenomenon occurred, and the adhesiveness dropped rapidly.

Note) ◎: Very good ○: Good ×: Bad

Erosion index: The higher the value, the lower the corrosion resistance.

Erosion test condition: slag C / S = 1, 1650 ℃ × 5 charges (30 minutes / 1 charge)

As can be seen from Table 2, the spray material for the secondary smelting furnace according to the present invention is thixotropic that the fluidity increases when stress is applied by using a clay system or a silicic acid system as a solid solution binder, and the fluidity decreases when the stress is removed. As the spray property is increased by development, it has excellent adhesion, water control property, and discharge property, and increases the strength at hot by the interaction of the binder added in the matrix, and thus wear resistance and corrosion resistance against slag and molten steel flow. It can be seen that this is improved.

Although Example 3 has the point that sclerosis | hardenability falls slightly, it turns out that hot intensity | strength and water | moisture-control range are about the same as or better than each comparative example.

As described above, the spray material for the secondary refining furnace according to the present invention has an effect of improving the quality of the steel while removing the influence of boron and phosphorus by adding a boron-free and low-phosphorous binder.

Claims (1)

Particle size 2-1mm natural magnesia clinker 19-21wt%, particle size 1mm or less natural magnesia clinker 59-61wt%, fine granular natural magnesia clinker 14-16wt%, phosphate 0.3-1.5wt% as a high solubility binder, silicic acid A spray material for secondary smelting furnace, comprising 0.5-3.5 wt%, clay-based 0.5-3 wt%, ultrafine silica 0.3-2 wt%, and calcium-based 0.5-4 wt%.