JP2018052752A - Monolithic refractory for use in extending work of blast furnace trough and its construction method - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an integrated material (a monolithic refractory for extending using both a slug portion and a metal portion of the lining of a blast furnace trough) having excellent adhesion to base materials (construction materials which have been previously applied to the slug portion and the metal portion of the lining of the blast furnace trough); and its construction method.SOLUTION: A monolithic refractory is composed of silicon carbide of 15 mass% or more to 30 mass% or less, boron carbide of 0.1 mass% or more to 3 mass% or less, carbon black of 0.5 mass% or more to 3 mass% or less as the raw materials. In these components, as to the silicon carbide, the content of fine powder having a particle size of 30 μm or less is set to be from 1 mass% or more to 7.5 mass% or less, based on 100 mass% of the components; and the mass ratio of boron carbide/(the total of silicon carbide as the fine powder and carbon black) is set to be from 0.05 or more to 2 or less. The monolithic refractory prepared by adding water to these components is applied in an extending manner to construction materials which have been previously applied to the slug portion and the metal portion of the lining of the blast furnace trough.SELECTED DRAWING: None

Description

  The present invention relates to an indeterminate refractory for use in an extension construction that doubles as a slag portion and a metal portion of a blast furnace lining, and a construction method thereof.

  The blast furnace has a role of a passage from the hot metal discharged from the blast furnace to a ladle, a kneading car, and the like. In recent years, from the viewpoint of workability, an irregular refractory material has been used for the lining in place of conventional bricks. Also, in the construction of irregular refractories on the blast furnace lining, so-called zone lining is generally performed in which the slag part (slag line part) and the metal part (metal line part) are constructed from different materials. (For example, refer to Patent Documents 1 and 2).

  However, in the case of zone lining, for example, even if only the damaged metal part is dismantled and repaired, the upper slag part that is healthy will be dismantled, resulting in an increase in the amount of construction of the irregular refractory. Incurs an increase in cost.

  In view of this, the application of a material that combines the slag portion and the metal portion (hereinafter also referred to as “integrated material”) has been studied. In the case of an integral material, the slag part and the metal part can be used together, so even if different materials are applied to the slag part and the metal part by zone lining, the slag part and the metal part Add-on construction that also serves as a facility becomes possible. However, when adding and constructing with an integral material, it is particularly important to ensure adhesion with a construction material (hereinafter also referred to as “base material”) pre-constructed on the slag part and the metal part. The study on the adhesiveness between the integral material and the base material has been insufficient.

JP 2000-203953 A JP 2010-235342 A

  The problem to be solved by the present invention is to provide an excellent material for the base material (the construction material preliminarily applied to the slag part and the metal part of the blast furnace lining). An object of the present invention is to provide an irregular refractory material for use in addition construction that combines a slag portion and a metal portion, and a construction method thereof.

According to the present invention, there is provided an amorphous refractory for the subsequent construction of a blast furnace pit, that is, an integral material and a construction method thereof.
(1) It is an unshaped refractory for blast furnace slag addition construction used for slag addition and slag part and metal part of the blast furnace saddle, with water added to the raw material composition,
In a proportion of 100% by mass of the raw material mixture, the silicon carbide raw material is 15% by mass to 30% by mass, the boron carbide raw material is 0.1% by mass to 3% by mass, and the carbon black is 0.5% by mass to 3% by mass. Containing less than mass%,
The content of fine powder having a particle size of 30 μm or less in the silicon carbide raw material is 1% by mass or more and 7.5% by mass or less in a proportion of 100% by mass of the raw material mixture,
An amorphous refractory material for blast furnace slag addition, wherein a mass ratio of the boron carbide raw material / (total amount of the fine silicon carbide raw material and the carbon black) is 0.05 or more and 2 or less.
(2) Addition of blast furnace slag as described in (1) above to blast furnace slag slag part and metal part of blast furnace saddle for construction material. Construction method for irregular refractories for construction.
(3) The construction method of the unshaped refractory material for blast furnace addition as described in (2), wherein the construction material is added after removing the deposits of the construction material applied in advance.

  Although details will be described later, the monolithic material of the present invention has a specific content of fine silicon carbide raw material having a particle size of 30 μm or less and a boron carbide raw material / (fine silicon carbide raw material and carbon having a particle size of 30 μm or less). By making the mass ratio of the total amount of black a specific range, it exhibits excellent adhesion to the base material. Therefore, the integral material of the present invention can be suitably used for the addition work that uses both the slag portion and the metal portion of the blast furnace lining, and the thickness of the addition work can be reduced. That is, according to the integral material of the present invention, it is possible to perform the construction without any problem after removing the deposits of the construction material, regardless of whether it is a slag portion or a metal portion. Thereby, the construction amount of the irregular refractory for repair can be reduced, and it can contribute to cost reduction.

  The integral material of the present invention is an irregular refractory material for blast furnace saddle construction that is used for slag construction and metal part of the blast furnace slag. Water is added to the raw material mixture in the same manner as the regular refractory.

  The integral material of the present invention is a proportion of 100% by mass of the raw material blend, 15% by mass to 30% by mass of the silicon carbide raw material, 0.1% by mass to 3% by mass of the boron carbide raw material, and 0% of carbon black. .5% by mass or more and 3% by mass or less. The content of fine powder having a particle size of 30 μm or less in the silicon carbide raw material is 1% by mass or more and 7.5% by mass or less in a proportion of 100% by mass of the raw material mixture, and the boron carbide raw material / (the fine powder of The mass ratio of the silicon carbide raw material and the carbon black (hereinafter simply referred to as “the mass ratio of the boron carbide raw material”) is 0.05 or more and 2 or less.

  Among these, the total content of the silicon carbide raw material is defined mainly from the viewpoint of securing metal resistance (molten metal resistance) and slag resistance, that is, corrosion resistance. Here, the silicon carbide raw material is excellent in slag resistance but not in metal resistance. Therefore, in the case of zone lining, as shown in Table 1 of Patent Document 1, a large amount (about 50% by mass) of silicon carbide raw material is contained for the slag part, and the content of silicon carbide raw material is relative for the metal part. To keep it low. As an integral material, it is necessary to ensure corrosion resistance in both the slag part and the metal part. In the actual blast furnace iron, the metal part is more chemically damaged than the slag part and requires corrosion resistance. Based on the fact that it is done, the content (15 to 30% by mass) with an emphasis on metal resistance was determined. A preferable range of the total content of the silicon carbide raw material is 18% by mass or more and 25% by mass or less.

In the silicon carbide raw material, the content of fine powder having a particle size of 30 μm or less is 1% by mass or more and 7.5% by mass or less as a proportion of 100% by mass of the raw material mixture as described above. That is, the monolithic material of the present invention actively contains a fine silicon carbide raw material having a particle size of 30 μm or less (hereinafter simply referred to as “fine silicon carbide raw material”). This is based on the following findings by the present inventors.
(A) Since the fine silicon carbide raw material is fine, it is easily oxidized, and when the silicon carbide raw material (SiC) is oxidized, a silica (SiO ₂ ) film is formed on the surface, resulting in physical volume expansion. This volume expansion improves the adhesion to the base material.
(B) Since the silica (SiO ₂ ) produced by the oxidation is a low melting point substance, the sinterability of the integral material is improved, and as a result, the adhesion to the base material is improved.

  From these points, the content of the fine silicon carbide raw material is 1% by mass or more. On the other hand, if the content of the fine silicon carbide raw material exceeds 7.5% by mass, the fine powder having a particle size of 30 μm or less becomes excessive, so that the fluidity of the integral material is impaired and the adhesiveness to the base material is lowered. On the other hand, if the fine powder content of the fine silicon carbide raw material exceeds 7.5% by mass, the silica (low melting point substance) produced by oxidation becomes excessive, so that the corrosion resistance, particularly the metal resistance is lowered. From these points, the upper limit of the content of the fine silicon carbide raw material was 7.5% by mass. The preferable content range of the fine silicon carbide raw material is 2% by mass or more and 5% by mass or less.

  Here, in the raw material composition of the integral material of the present invention, the total content of the silicon carbide raw material is 15% by mass or more and 30% by mass or less, and the content of the fine silicon carbide raw material is 1% by mass or more and 7.5% by mass. Therefore, silicon carbide raw materials other than fine silicon carbide raw materials are necessarily included. The particle size constitution of the silicon carbide raw material other than the fine silicon carbide raw material is not particularly limited, but the maximum particle size (top size) of the silicon carbide raw material other than the fine silicon carbide raw material is further improved from the point of further improving the adhesion to the base material. It is preferable to be less than 1 mm.

Next, boron carbide raw materials will be described. Conventionally, boron carbide raw materials generally contain an amount corresponding to the content of these silicon carbide raw materials and carbon black as antioxidants such as silicon carbide raw materials and carbon black (carbon raw materials). However, based on the following knowledge, the present inventors decided to contain a boron carbide raw material in a larger amount than the content as a conventional antioxidant.
(C) The boron carbide raw material (B ₄ C), when oxidized, becomes boron oxide (B ₂ O ₃ ). This boron oxide (B ₂ O ₃ ) is a low-melting substance as in the case of the silica (SiO ₂ ). Therefore, these combine to improve the sinterability of the integral material, and as a result, improve the adhesion to the base material.
(D) Boron oxide (B ₂ O ₃ ) generated by oxidation of the boron carbide raw material (B ₄ C) generates a very viscous liquid phase during sintering of the integral material. When a very viscous liquid phase is generated during sintering, sintering shrinkage is suppressed, and as a result, adhesion to the base material is improved.

  From these points, the content of the boron carbide raw material is set to 0.1% by mass or more, and the mass ratio of the boron carbide raw material is set to 0.05 or more. On the other hand, when the boron carbide raw material is excessive, the boron oxide (low melting point substance) produced by the oxidation of the boron carbide raw material becomes excessive, so that the corrosion resistance, particularly the metal resistance is lowered. In addition, since the boron carbide raw material has low wettability to water, the fluidity of the integral material is impaired if the boron carbide raw material is excessive. From these points, the upper limit of the content of the boron carbide raw material is 3% by mass, and the upper limit of the mass ratio of the boron carbide raw material is 2. A preferable range of the content of the boron carbide raw material is 0.3 to 1% by mass, and a preferable range of the mass ratio of the boron carbide raw material is 0.1 to 1.5.

  Next, carbon black is contained in an amount of 0.5% by mass or more and 3% by mass or less in order to improve fluidity mainly due to the bearing effect. When the fluidity is improved, a small amount of water is required, so that the compactness of the construction body is improved, which contributes to the improvement of metal resistance, slag resistance and adhesion to the base material. If the carbon black content is less than 0.5% by mass, the bearing effect cannot be obtained and the fluidity is lowered. On the other hand, when the content of carbon black exceeds 3% by mass, since carbon black has poor dispersibility, the adverse effect thereof becomes remarkable. On the contrary, the fluidity is lowered and the adhesion to the base material is also lowered.

  Here, in the raw material composition of the integral material of the present invention, it is preferable that the remainder other than the aforementioned silicon carbide raw material, boron carbide raw material and carbon black mainly comprises an alumina raw material from the viewpoint of contributing to corrosion resistance. Specifically, it is preferable to contain 60% by mass or more and 80% by mass or less of the alumina raw material in a ratio of 100% by mass of the raw material mixture. In addition to the above-mentioned refractory raw material, the raw material composition of the integral material of the present invention, as with the raw material composition of ordinary amorphous refractory, as additives, binder, dispersant, curing modifier, An explosion prevention agent or the like is appropriately contained.

  As the binder, one or more selected from alumina cement, colloidal silica, hydraulic transition alumina, phosphate, and silicate can be used.

  Examples of the dispersant include alkali metal phosphates such as sodium tripolyphosphate, sodium hexametaphosphate, sodium ultrapolyphosphate, sodium hexametaphosphate, polycarboxylate such as sodium polycarboxylate, alkylsulfonate, aromatic One or more selected from sulfonates, sodium polyacrylate, sodium sulfonate, and the like can be used.

  The curing time adjusting agent includes a curing accelerator and a curing retarder. As the curing accelerator, for example, one or more selected from slaked lime, calcium chloride, sodium aluminate, lithium carbonate, and the like can be used. As the curing retarder, for example, one or more selected from boric acid, oxalic acid, citric acid, gluconic acid, sodium carbonate, sugar and the like can be used.

Examples of the explosion preventing agent include metal aluminum, aluminum lactate, and organic fiber (eg, vinylon fiber, polyethylene fiber, polypropylene fiber, etc.).

  As described above, since the integral material of the present invention exhibits excellent adhesion to the base material, it can be suitably used for the addition work that combines the slag portion and metal portion of the blast furnace lining, The thickness of the construction can be reduced. Therefore, according to the integral material of the present invention, regardless of whether it is a slag part or a metal part, it is possible to perform the construction without any problem after removing the deposits on the construction material. Thereby, the construction amount of the irregular refractory for repair can be reduced, and it can contribute to cost reduction.

  In addition, although the addition construction by the integral material of this invention is based on pouring construction, it can also be set as spray construction or iron coating construction.

  About the amorphous refractory material obtained by adding 5.3% by mass of water as an outer shell to 100% by mass of the raw material composition of each example shown in Table 1, adhesion, slag resistance, metal resistance and flow Sex was evaluated as follows.

  In Examples and Comparative Examples shown in Table 1, raw materials having different proportions of fine silicon carbide raw materials having a particle size of 30 μm or less were used in the silicon carbide raw materials. Specifically, Examples 1 and 6 and Comparative Examples 2 and 5-8 are used for the silicon carbide raw material A shown in Table 2, Examples 2 and 7 are provided for the silicon carbide raw material B, Examples 1 and 7 are provided for the silicon carbide raw material C. 3, 5, silicon carbide raw material D was used in Example 4, silicon carbide raw material E was used in Comparative Example 3, and silicon carbide raw material F was used in Comparative Example 4.

<Evaluation of adhesion to slag material>
First, 60% by mass of a silicon carbide raw material, 30% by mass of an alumina raw material, 5% by mass of a carbon raw material, and 6% by mass of water are added to a raw material mixture in which a binder and a dispersant are added to the balance, and 40 × 40 × It is cast into a shape of 80 mm, dried at 110 ° C., and then reduced and fired at 1450 ° C. Thereby, the test piece of the material (slag material) constructed in a slag part as a base material is obtained.
This test piece is set in a frame of 40 × 40 × 160 mm, and the unfixed refractory material of each example is poured into one side of the test piece as an integrated material by simulating the addition work, dried at 110 ° C., and reduced at 1450 ° C. Firing is performed. Then, a load is applied to the bonding surface between the test piece as a base material and the integral material by a method of measuring bending strength (based on JISR2553). The bending strength obtained as a result is defined as the adhesive strength. The higher the adhesive strength, the better the adhesion to the base material. In Table 1, the case where the adhesive strength is 5 MPa or more is indicated by ◯, the case where it is 3 MPa or more and less than 5 MPa, and the case where it is less than 3 MPa are indicated by ×.

<Evaluation of adhesion to metal materials>
First, 20% by mass of an alumina raw material, 55% by mass of a spinel raw material, 15% by mass of a silicon carbide raw material, 5% by mass of a carbon raw material, and 5.3% by mass of water with respect to a raw material mixture in which a binder and a dispersant are blended in the balance It is added, cast into a 40 × 40 × 80 mm shape, dried at 110 ° C., and then reduced and fired at 1450 ° C. Thereby, the test piece of the material (metal material) constructed in a metal part as a base material is obtained.
This test piece is set in a frame of 40 × 40 × 160 mm, and the unfixed refractory material of each example is poured into one side of the test piece as an integrated material by simulating the addition work, dried at 110 ° C., and reduced at 1450 ° C. Firing is performed. The test method is the same as the evaluation of adhesion to the slag material.

<Slag resistance>
The amorphous refractory of each example is poured into a predetermined mold, cured and dried to obtain a test piece. The test piece is subjected to a test by a rotating drum erosion test method using an erodant as a blast furnace slag. After the test, the erosion dimension of the test piece is measured, and the value obtained by dividing the erosion dimension of the test piece of Example 1 by 100 is obtained as the erosion index. The smaller the erosion index, the better the slag resistance. In Table 1, the case where the erosion index is 110 or less is indicated by ○, the case where it is more than 110 or less is indicated by Δ, and the case where it is more than 120 is indicated by ×.

<Metal resistance>
The amorphous refractory of each example is poured into a predetermined mold, cured and dried to obtain a test piece. The test piece is subjected to a test by a rotating drum erosion test method using blast furnace slag and pig iron as erosion agents. After the test, the erosion dimension of the test piece is measured, and the value obtained by dividing the erosion dimension of the test piece of Example 1 by 100 is obtained as the erosion index. The smaller the melting index, the better the metal resistance. In Table 1, the case where the erosion index is 110 or less is indicated by ○, the case where it is more than 110 or less is indicated by Δ, and the case where it is more than 120 is indicated by ×. In the evaluation of metal resistance, the reason why blast furnace slag is added to the erodant is that the molten iron and slag are stirred and mixed in an actual blast furnace so as to come into contact with the slag even in the metal part.

<Fluidity>
The tap flow value is obtained in accordance with JIS R2521 for the irregular refractories in each example. The larger the tap flow value, the better the fluidity. In Table 1, a case where the tap flow value is 150 mm or more is indicated by ◯, a case where the tap flow value is 130 mm or more and less than 150 mm is indicated by Δ, and a case where the tap flow value is less than 130 mm is indicated by ×.

  In Table 1, Examples 1 to 7 are examples in which the composition of the raw material blend was within the scope of the present invention, and all of the adhesiveness, slag property, metal resistance, and fluidity were good. In particular, Example 1 in which the composition of the raw material blend was within the preferred range had particularly good characteristics described above.

  On the other hand, Comparative Example 1 is an example in which the total content of the silicon carbide raw material is small, and the slag resistance is lowered. In addition, the metal resistance also decreased due to reasons such as the inclusion of blast furnace slag in the erodant. On the other hand, Comparative Example 2 is an example in which the total content of the silicon carbide raw material is large, and the metal resistance decreased.

  Comparative Example 3 was an example in which the content of fine silicon carbide raw material was small, and the adhesiveness was lowered. Moreover, the effect of the slag resistance improvement by a silicon carbide raw material was not acquired, and slag resistance also fell. On the other hand, Comparative Example 4 is an example in which the content of the fine silicon carbide raw material is large, and the metal resistance is lowered. Moreover, since fine powder with a particle size of 30 μm or less increased, the fluidity decreased and the adhesiveness also decreased.

  Comparative Example 5 is an example in which the content of the boron carbide raw material is small and the mass ratio of the boron carbide raw material is small. The effect of improving the adhesiveness by the boron carbide raw material described above cannot be obtained, and the adhesiveness is lowered. Further, the effect of preventing oxidation of silicon carbide raw material and carbon black by the boron carbide raw material was not obtained, and the slag resistance was also lowered. On the other hand, Comparative Example 6 is an example in which the content of the boron carbide raw material is large and the mass ratio of the boron carbide raw material is large. As described above, since the boron carbide raw material has low wettability to water, if there is too much boron carbide raw material, the fluidity is lowered, and accordingly, the slag resistance and metal resistance are also lowered.

  Comparative Example 7 is an example in which the content of carbon black is small, specifically, no carbon black is contained, and the fluidity is lowered. On the other hand, Comparative Example 8 is an example having a high carbon black content. As described above, since carbon black has poor dispersibility, if there is too much carbon black, the fluidity is lowered, and the adhesiveness and metal resistance are also lowered accordingly.

Claims (3)

It is an unshaped refractory material for blast furnace saddle construction that is used for slag construction and slag part and metal part of blast furnace saddle, which is made by adding water to the raw material mixture,
In a proportion of 100% by mass of the raw material mixture, the silicon carbide raw material is 15% by mass to 30% by mass, the boron carbide raw material is 0.1% by mass to 3% by mass, and the carbon black is 0.5% by mass to 3% by mass. Containing less than mass%,
The content of fine powder having a particle size of 30 μm or less in the silicon carbide raw material is 1% by mass or more and 7.5% by mass or less in a proportion of 100% by mass of the raw material mixture,
An amorphous refractory material for blast furnace slag addition, wherein a mass ratio of the boron carbide raw material / (total amount of the fine silicon carbide raw material and the carbon black) is 0.05 or more and 2 or less.   The refractory material for blast furnace slag addition construction according to claim 1 is added to the construction material previously applied to the slag part and metal part of the blast furnace slag lining. Refractory construction method.   The construction method of the irregular refractory material for the blast furnace slag addition construction according to claim 2, wherein the construction is performed after removing the deposits of the construction material previously constructed.