JP2009292692A - Blocking material for tap hole in blast furnace - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To reduce the generation of caves while securing the depth of a tap hole and a tapping time and as a result, to attain the improvement of blast furnace operation rate, the reduction of use quantity of a mud material and the lightening of work load. <P>SOLUTION: In the blocking material for the tap hole in the blast furnace which is formed by kneading powder comprising refractory aggregate and refractory fine powder with tar and/or phenol resin, the content of CaO after a volatile component is removed is controlled to be 0.2-10 mass%. As a CaO source, a combined material, which contains a CaO component and is selected from a group of alumina cement, portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate, and slaked lime, is used singularly or by combining two or more. <P>COPYRIGHT: (C)2010,JPO&INPIT

Description

  TECHNICAL FIELD The present invention relates to a tap hole closing material (hereinafter also referred to as “mud material”), and more particularly, to a blast furnace tap hole closing material used to fill a tap hole of a blast furnace and close the tap hole. .

  For stable operation of a blast furnace, the importance of the performance of a blast furnace discharge hole closing material (mud material) used to fill the discharge hole of the blast furnace and close the discharge hole is increasing. In particular, due to the increase in the extraction speed accompanying the increase in size and pressure of the blast furnace in recent years, higher durability is required for the mud material.

  The main properties required for the mud material are corrosion resistance against hot metal and slag, opening ability to smoothly open the tap hole, filling ability when closing the tap hole, and remaining in the tap hole. Adhesion with mud deposits (hereinafter referred to as “old mud”). In particular, the openability of the tap hole requires a small number of side holes (also referred to as hole breaks). In addition, as the life of the blast furnace is extended, it is necessary to keep the tap hole depth long from the viewpoint of protecting the furnace wall.

When the number of horizontal holes increases, the hot metal is inserted in the process of opening the tap hole, the tip of the drill becomes worn and drilling becomes impossible (that is, the hot metal cannot be penetrated and the hot metal is discharged from the blast furnace furnace). Will not be possible and will hinder the operation of the blast furnace.
Moreover, when a horizontal hole is generated, excavation cannot be performed and it may be necessary to refill the mud material. This leads to an increase in the amount of use of the mud material, which not only increases the original unit price of the mud material but also increases the work load, which is not preferable.

As an aspect of the generation of the horizontal hole,
(1) Due to insufficient adhesion between the old mud material and the newly filled mud material, hot metal enters the bonding surface and becomes a horizontal hole.
(2) If a crack occurs in the old mud material, or a crack occurs in the newly filled mud material, and hot metal enters the cracked part and becomes a horizontal hole,
(3) The firing strength of the mud material is increased, and the mud material becomes hard when the hole is opened. For example, when it enters and becomes a horizontal hole.

By the way, in order to reduce the problem related to the adhesion between the old mud material and the newly filled mud material described in (1) above, a mud material using a wax stone as a refractory aggregate has been proposed ( (See Patent Documents 1 and 2).
In this mud material, the wax has a function of expanding the volume at 1200 ° C. or higher and improving the adhesion in the tap hole. In addition, the wax component SiO2 produces a low-melting substance, and functions to improve adhesion to the old mud material.

Further, as a mud material capable of suppressing the crack of (2) above, a mud material in which the addition amount of clay and carbon black is adjusted has been proposed (see Patent Documents 3 and 4).
In this mud material, the porosity after baking at 1400 ° C. can be reduced by adjusting the addition amounts of clay and carbon black, and the mud material can be densified and cracks can be suppressed.

Further, as a mud material that can suppress the hardening of the mud material of the above (3), a mud material that can suppress the progress of sintering by adding earth graphite has been proposed. (See Patent Document 5).
In this mud material, the addition of earth-like graphite suppresses the progress of sintering, making it possible to facilitate the hole opening operation.
JP 2000-53472 A JP 2001-335374 A Japanese Patent No. 2992211 Japanese Patent Application Laid-Open No. 11-199337 JP 2004-35354 A

However, the above-described prior art has a certain effect in reducing the lateral holes, but has a problem that sufficient durability cannot be obtained. In particular, when a large amount of wax is used, there is a problem that the slag resistance is lowered, and the speed of enlargement of the diameter of the tap hole is increased, so that the tapping time is shortened.
In addition, when a large amount of carbon black or earthy graphite is used, there is a problem that it is difficult to keep the tap hole long because the metal resistance is lowered.

  The present invention solves the above-mentioned problem, and it is possible to reduce the occurrence of lateral holes, and to secure the tapping time and maintain the tapping hole depth, the blast furnace tapping hole closure The purpose is to provide materials.

In order to solve the above-mentioned problems,
A blast furnace tap hole closing material formed by kneading a powder composed of a refractory aggregate and a refractory fine powder with tar and / or phenol resin,
It is characterized by containing CaO in a ratio of 0.2 to 10 mass% in a state after the volatile matter is removed.

  In addition, in the blast furnace tap hole closing material of the present invention, as a CaO source, a substance selected from the group consisting of alumina cement, Portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate, slaked lime, Alternatively, it is preferable to use a combination of two or more.

  In the blast furnace outlet hole plugging material (mud material) of the present invention, CaO is contained in a ratio of 0.2 to 10 mass% after the volatile matter is removed. It is possible to reduce the lateral hole while ensuring the depth and the spear time. As a result, the blast furnace operating rate can be improved, and the amount of mud used can be reduced and the workload can be reduced. Therefore, the blast furnace tap hole closing material of the present invention has high industrial value.

  In the blast furnace tapping hole closing material (mud material) of the present invention, as a CaO source, a substance selected from the group consisting of alumina cement, Portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate, slaked lime is used alone. In addition, by using two or more types in combination, it is possible to provide a blast furnace tap hole closing material that exhibits the above-mentioned effects without causing an increase in cost, making the present invention more effective. It becomes possible to storm.

  In the blast furnace tapping hole plugging material (mud material) of the present invention, it is preferable that the ratio of the CaO component after the removal of volatile components is in the range of 0.2 to 10 mass%. If it is less than 0.2 mass%, the adhesiveness between mud materials becomes insufficient, and the effect of preventing lateral holes cannot be obtained sufficiently.

For example, oxides of SiO ₂ -Al ₂ O ₃ -based containing no CaO or be added to bentonite (SiO ₂ one Al ₂ 0 ₃ -CaO) to trace containing CaO, is filled in the old mud material and new It has been confirmed that the adhesive strength with the mud material cannot be significantly improved.

Moreover, since the corrosion resistance of a mud material will fall when the ratio of a CaO component exceeds 10 mass%, since durability falls, especially a tapping time and a tapping depth are unpreferable.
That is, as a CaO source, a composite material containing CaO components such as alumina cement, Portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate, slaked lime, and the content ratio of CaO after the volatile matter is removed. By adding so that it becomes the range of 0.2-10 mass%, it becomes possible to improve the adhesive strength of mud materials.

In the present invention, for example, when blast furnace slag is used as the CaO source, the composition of the blast furnace slag (CaO source) has a melting point as can be seen from the SiO ₂ -Al ₂ O ₃ —CaO system phase diagram shown in FIG. Is around 1315 ° C to 1400 ° C.
On the other hand, the temperature of the hot metal and slag generated in the blast furnace is approximately 1500 to 1550 ° C.
Therefore, the melting point of the CaO source (blast furnace slag) contained in the mud material is lower than the temperature of the hot metal and slag generated in the blast furnace, and this part is used when the mud material of the present invention is used in an actual machine. It melts and penetrates between the particles that make up the mud material to dissolve the components of the particles until they reach an equilibrium composition at that temperature. Because of this effect, the muds are fused together, so that the adhesive strength between the old mud material and the newly filled mud material is improved.

  In addition, when the amount of CaO-containing material, which is the source of CaO, is too large, the amount of melt between particles increases and a large amount of mud material components dissolve, resulting in a decrease in corrosion resistance and a reduction in the time and output time. The fistula depth is significantly reduced.

  Moreover, the composite material containing CaO components such as alumina cement, Portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate, slaked lime as a CaO source has a CaO component in the range of 0.2 to 10 mass%. As such, they may be used alone or in combination of two or more.

  In addition, in the blast furnace tap hole closing material (mud material) of the present invention, natural bauxite, band shale, fused alumina, brazing, which are generally used for mud materials as refractory raw materials (refractory aggregate and refractory fine powder). Stones, silicon carbide, iron iron nitride, clay, silica fume, coke, carbon black, earth graphite, powder pitch, metallic silicon, ferrosilicon, metallic aluminum, and the like can be contained in various proportions.

  Further, in the blast furnace tap hole closing material (mud material) of the present invention, a residual carbon organic compound is used as a binder, and examples of the residual carbon organic compound include anhydrous tar and phenol resin.

  According to the blast furnace tap hole closing material (mud material) of the present invention configured as described above, the adhesiveness between the old mud material and the newly filled mud material is improved, and the occurrence of lateral holes is reduced. In addition, high durability can be realized (ensuring the brewing time and maintaining the brewing hole depth).

  Examples of the present invention will be described below to describe the features of the present invention in more detail.

Alumina fine powder, wax stone, silicon carbide, coke, silicon nitride iron, clay, carbon black, earthy graphite, powdery pitch, metal silicon, metal aluminum, CaO-containing substance (in this example) Blast furnace slag) and a blast furnace slag hole plugging material (mud material) formed by blending anhydrous tar at a predetermined ratio were prepared and subjected to the following corrosion resistance test, adhesion test, and actual machine test.
The composition of blast furnace slag SiO ₂ is _{34 · 8%, Al 2 0} 3 is 14.4%, CaO is 42.9%, MgO was used as 6.8%.

[Corrosion resistance test]
The mud material was pressure-molded into a 40 × 40 × 160 mm rectangular parallelepiped shape at 4 MPa, and then subjected to a heat treatment at 500 ° C. for 4 hours in a coke breeze to remove volatile matter, and this was used as a sample.

The corrosion resistance of the samples thus obtained was evaluated by a high frequency furnace lining method. The corrosion resistance was evaluated by using pig iron and blast furnace slag and holding at 1580 ° C. for 5 hours. In addition, in order to prevent saturation of a slag component, slag was replaced once per hour.
And after completion | finish of a test, the sample was cut | disconnected in the center and the erosion area in the cut surface of the part which was contacting slag was measured.

  The results are also shown in Table 1. In addition, the erosion area was represented by a erosion index where the erosion area of Comparative Example 1 in which no CaO-containing material (in this example, blast furnace slag) was added was 100. That is, the smaller the erosion index, the better the corrosion resistance.

[Adhesion test]
The specimen to be bonded was pressure-molded at 4 MPa into a 40 × 40 × 80 mm rectangular parallelepiped mud material of the above-described composition, and then heated at 500 ° C. for 4 hours in a coke breeze. After removing the volatile matter by performing, reduction firing at 1400 ° C. for 3 hours in a coke breeze was used.

And as shown in FIG. 2, the raw mud which pressure-molded the raw mud material in the shape of a 40x40x80 mm rectangular parallelepiped at 4MPa in the post-baking mud molding 1 which performed the reduction baking of 1400 degreeC x 3 hours. The molded body 2 was adhered. The bonding pressure to the mud molded body 1 after firing the raw mud molded body 2 was also set to 4 MPa.
Thereafter, the baked mud molded body 1 and the raw mud molded body 2 joined body 3 are heated in a coke breeze at 500 ° C. for 4 hours to remove volatile components, and then 1400 in the coke breeze. Reduction baking at 3 ° C. for 3 hours was performed.

  Then, using the fired joined body as a sample, a three-point bending test is performed by a method as shown in FIG. 3 using a three-point bending tester, and the force when the joined body breaks or peels off at the joined portion. Is the adhesive strength.

  Table 1 also shows the adhesive strength examined as described above. It shows that the adhesiveness of mud materials is so favorable that the value of adhesive strength is large. In addition, it is preferable that the adhesiveness between the mud materials is higher because the penetration of the hot metal is suppressed and the generation of lateral holes is reduced.

[Real machine test]
The mud materials shown in Table 1 were actually filled into the tap holes of a 5,000 m3 class blast furnace using a mud gun, and the tap hole depth, the tap time, and the occurrence rate of the horizontal holes were investigated.
The results are also shown in Table 1.

  As shown in Table 1, in the samples of Examples 1 to 5 that satisfy the requirements of the present invention, the melting index decreases slightly as the addition amount of blast furnace slag as a CaO source increases, but the adhesion strength improves. It was confirmed.

  In addition, in the actual machine test, in the case of the samples of Examples 1 to 5 that satisfy the requirements of the present invention, when the amount of addition of the blast furnace slag of the CaO source increases, the horizontal hole generation rate decreases, and the tap hole depth hardly changes. It was confirmed that there was no problem, and the tapping time tended to be slightly shorter when the addition amount of blast furnace slag of the CaO source was increased, but it was confirmed that it was at a level where there was no problem in practical use. . Moreover, in the case of the sample of Examples 1-5, it was confirmed in any case that the effect of reducing a horizontal hole generation rate is acquired.

  On the other hand, Comparative Example 1, which is a conventional mud material, has low adhesive strength, and in the actual machine use results, there is no problem with the depth of the tap hole and the tap time, but there is a high rate of occurrence of the horizontal hole and a problem in practical use It was confirmed that there is.

  Moreover, in the case of the sample of Comparative Example 2 to which a small amount of CaO source blast furnace slag was added, it was confirmed that the adhesion strength was only slightly improved. In addition, it was confirmed that the horizontal hole generation rate hardly decreased in the actual machine use results, and the effect was insufficient.

  In addition, in the case of the sample of Comparative Example 3 in which a large amount of CaO source blast furnace slag was added beyond the scope of the present invention, it was confirmed that although the adhesion strength was improved, the erosion index was significantly reduced. Moreover, in the case of this comparative example 3, since the fall of the tapping hole depth and tapping time is expected when using the actual machine, it was not used in the actual machine.

  In the above examples, blast furnace slag is used as a CaO source, but when using any of converter slag, alumina cement, Portland cement, calcia clinker, calcium carbonate, and slaked lime as a CaO source, It has been confirmed that almost the same effect can be obtained.

By using the blast furnace pit hole closing material of the present invention, it becomes possible to reduce the rate of occurrence of horizontal holes while securing the pit hole depth and the brewing time, resulting in an improvement in the blast furnace operating rate. The amount of mud used can be reduced and the work load can be reduced.
Therefore, the present invention has extremely high industrial value, and can be widely used as a mud material used for filling the blast furnace pit and closing the pit.

It is a phase diagram of the SiO ₂ —A1 ₂ 0 ₃ —CaO system. It is a figure which shows the preparation methods of the sample (joint body of a mud material) which used for the adhesive test in the Example of this invention. It is a figure explaining the method of performing a 3 point | piece bending test about the joined body after baking, in order to investigate adhesive strength.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Mud molded body after baking 2 Raw mud molded body 3 Joined body of mud molded body and raw mud molded body after baking

Claims (2)

A blast furnace tap hole closing material formed by kneading a powder composed of a refractory aggregate and a refractory fine powder with tar and / or phenol resin,
In the state after the volatile matter has been removed, CaO is contained at a ratio of 0.2 to 10 mass%.   A material selected from the group consisting of alumina cement, Portland cement, blast furnace slag, converter slag, calcia clinker, calcium carbonate and slaked lime is used alone or in combination of two or more as a CaO source. 1. A blast furnace tapping hole closure material according to 1.

Images