TW200938509A - Aluminum compound-bonded brick for furnace hearth - Google Patents

Abstract

Disclosed is an aluminum compound-bonded brick for a furnace hearth that has a long service life, causes no significant energy loss, and has high durability. The aluminum compound-bonded brick for a furnace hearth is produced by adding a binder to a refractory material formulation comprising 85 to 99% by mass of alumina and 1 to 15% by mass of an aluminum powder as main components, free from a carbonaceous material, and having a Si content of not more than 3% by mass, or a refractory material formulation comprising 55 to 94% by mass of alumina, 5 to 30% by mass of a carbonaceous material, and 1 to 15% by mass of an aluminum powder as main components and having a Si content of not more than 3% by mass, kneading the mixture, molding the kneaded product, and firing the molded product in a nitrogen atmosphere or in carbon particles at 1000 DEG C or above.

Description

200938509 IX. INSTRUCTIONS OF THE INVENTION [Technical Field] The present invention relates to a refractory brick for a blast furnace hearth which is lined with an aluminum compound as a cemented structure in a hearth portion of the hearth portion which is lower than the blast furnace pig iron outlet and is in contact with the molten pig iron. . [Prior Art] 熟 In the hearth of the blast furnace, clinker bricks, high alumina bricks,

Sialon cemented alumina bricks, tantalum carbide cemented alumina carbon bricks, or carbon bricks. • These bricks are damaged by reaction with molten pig iron during long-term use. Although the furnace abdomen and the vertical pit portion of the refractory in the blast furnace can be prolonged by the repair of the amorphous refractory material, the life of the hearth brick determines the life of the blast furnace because the hearth portion is difficult to repair. Therefore, bricks for the hearth of the long life have been desired from the past. For example, in Patent Document 1, it is disclosed that the side wall portion and the furnace bottom which are accumulated in the blast furnace hydrothermal fluid are 50 to 85% by mass, 5 to 15% of alumina, and 5 to 15% of metal bismuth in mass ratio%. And a total of 5 to 20% of vanadium, niobium, molybdenum or one or more of the carbides, nitrides, and carbides of these elements. When the carbonaceous refractory is in contact with the molten iron, particularly the molten pig iron, the carbon aggregate is dissolved by carbon and consumed, and if the carbonaceous refractory contains alumina or the like, they remain in the carbon after the carbonaceous material is eluted. The surface of the refractory material is interposed between the carbonaceous refractory and the molten pig iron, hinders the contact of the carbonaceous refractory with the molten pig iron, and reduces the consumption rate of the carbonaceous refractory. However, when the carbonaceous refractory contains a large amount of alumina, the remaining alumina layer after the carbonaceous material is eluted covers the entire surface of the carbonaceous refractory, and as a result, the balance is resistant to molten iron and slag resistance. The description must be such that the content of alumina is within an appropriate range. Further, an aluminum compound cemented brick having aluminum compound such as aluminum nitride, aluminum carbide, aluminum carbonate, or aluminum oxide as a main cementing structure, wherein an aluminum compound cemented brick which also uses aluminum nitride as a cemented structure is difficult to wet with molten metal It has a high thermal conductivity and has been reviewed for use in blast furnace bricks. For example, in the carbon raw material such as artificial graphite or roasting smokeless carbon, 0.1 to 20% by weight of the Α1 powder having an average particle diameter of 25 μm and after being kneaded with the organic binder, The blast furnace carbonaceous brick is obtained by calcining in a CO-reducing atmosphere or a nitrogen-inert atmosphere to obtain a part of the open pores which are filled with fibrous Α12〇3, Α1Ν crystal, or aluminum oxynitride crystal. It is described that the carbon brick is repeatedly evaporated and solidified in the blast furnace, and the alkali component such as potassium which is circulated in the furnace is suppressed to improve alkali resistance. Further, in Patent Document 3, a molded article formed of alumina, natural graphite, and aluminum is placed in a container that can be sealed, and is calcined in a state of being filled with tantalum nitride to cause aluminum to react via an oxygen phase. Nitrogen is easy to obtain aluminum nitride cemented refractory bricks. However, this aluminum nitride cemented refractory brick is not described in the hearth portion of the blast furnace. [Patent Document 1] JP-A-2003-95742 [Patent Document 2] Japanese Laid-Open Patent Publication No. Hei No. Hei No. Hei. No. 2004-83365 No. 200938509. In the brick disclosed in the above-mentioned Patent Document 1, the carbon disclosed in Patent Document 2 uses only carbon such as artificial graphite or roasting smokeless carbon except for aluminum. Raw materials, both are multi-carbon bricks. When a brick having a large carbon content is used in a blast furnace hearth as described in Patent Document 1, carbon is easily eluted into molten pig iron and has poor durability. Therefore, the cooling from the outside of the furnace is enhanced and the brick forms a molten pig iron viscous layer on the running surface, and durability is ensured by preventing carbon from being eluted into the molten pig iron. However, this type of cooling from outside the furnace brings about a large loss of energy. The brick disclosed in the above Patent Document 3 is used in the hearth portion of the blast furnace, and satisfactory durability has not yet been obtained. An object of the present invention is to provide a blast furnace hearth brick which has a long life and a low energy loss and high durability. ❿ (Means for Solving the Problem) The inventors of the present invention conducted various kinds of uranium resistance tests on molten pig iron using aluminum nitride and aluminum oxycarbide (Al2OC or A1404C) as a refractory of a cemented structure, and found that it is a cemented structure. The aluminum nitride and the aluminum oxide are temporarily dissolved in the molten pig iron in an aluminum type, and the aluminum is oxidized to alumina immediately thereafter, and the alumina is deposited on the surface of the aluminum compound to hinder the corrosion resistance. At the same time, in the aforementioned corrosion resistance test, bricks containing Si such as clinker brick, high oxidation 200938509 aluminum brick, Sialon cemented alumina brick, carbonized tantalum cemented alumina carbon brick, etc. were found, and Si dissolved in molten pig iron. However, it does not precipitate on the surface of the brick in the form of cerium oxide. The higher the Si content, the worse the corrosion resistance. According to the above findings, the brick of the present invention has a structure in which an aluminum compound containing alumina as a main component is used as a cemented structure and has a small Si content, and the brick of the present invention is applied to a blast furnace hearth portion which is in contact with molten pig iron for a long period of time. Compared with the bricks of the previous blast furnace hearth, it is characterized by excellent corrosion resistance and low thermal conductivity. That is, the first aspect of the aluminum compound cemented brick for a blast furnace hearth according to the present invention is that the main component is composed of alumina and aluminum powder, and contains 85 to 99% by mass of alumina and 1 to 15% by mass of aluminum powder. In addition, a blast furnace obtained by calcining a refractory raw material having a carbon content of not more than 3% by mass and containing a binder and kneading it in a nitrogen atmosphere or a carbon particle at a temperature of 1 000 ° C or higher. The hearth is cemented with aluminum compounds. The second aspect of the aluminum cement brick for a blast furnace hearth according to the present invention is that the main component 〇 is composed of alumina and a carbonaceous material and aluminum powder, and contains 55 to 94% by mass of alumina and 5 to 30% by mass of carbonaceous material. a raw material and 1 to 15% by mass of aluminum powder, and a refractory raw material complex having a Si content of 3% by mass or less, after adding a binder and kneading the molding, in a nitrogen atmosphere or in a carbon particle at 10 ° C The blast furnace hearth obtained by calcining above is cemented with an aluminum compound. In the aluminum compound cemented brick for the blast furnace hearth of the present invention, the aluminum powder in the refractory raw material complex is formed into a brick, and then heated to become aluminum nitride by heating in a nitrogen atmosphere, and further, is filled with carbon in the vessel. When calcined in a CO-containing atmosphere in a granular state, carbon oxide-8-200938509 aluminum which mainly becomes Al2OC or A1404C, by mutual sintering, forms a dense and strong cemented structure in the brick. Further, the formed aluminum nitride or aluminum carbonate is in the form of fine fibers or needles, and is filled in the open pores of the brick to grow, so that the substantial open pores of the brick are reduced and the molten pig iron can be inhibited from infiltrating into In the bricks. Further, since the cemented structure of aluminum nitride and aluminum carbonate is not contained in Si and is difficult to wet the molten pig iron, the corrosion resistance to molten pig iron is extremely excellent. The aluminum powder is blended in an amount of 1 to 15% by mass, more preferably from 5 to 13% by mass, based on the refractory raw material composition. When the amount is less than 1% by mass, the amount of the formed aluminum nitride and the amount of the alumina decreases, so that the cemented structure is insufficient and the strength is insufficient. When the amount is more than 15% by mass, a slight volume increase is accumulated with the formation of aluminum nitride and aluminum carbonate, and cracking occurs during firing, which results in a decrease in production yield. The main component of the refractory raw material of the aluminum compound cemented brick for the blast furnace hearth of the present invention is composed of alumina and aluminum powder (containing no carbonaceous raw material), or alumina and carbonaceous raw materials and aluminum powder. It is most suitable for use as a furnace for the hearth of a blast furnace, in which the alumina does not react with the molten pig iron W and the corrosion resistance is extremely excellent, and it is not deteriorated even if it is used for a long period of time (10 years or more) and has a low thermal conductivity. raw material. In the case where the refractory raw material complex is composed of alumina and aluminum powder as a main component, the alumina is used in an amount of 85 to 99% by mass, more preferably 90 to 99%. When the amount is less than 85% by mass, the corrosion resistance is insufficient. When the amount is more than 99% by mass, the aluminum powder is relatively insufficient and the cemented structure is decreased, so that the strength is insufficient. An aluminum compound cemented brick produced using this refractory raw material complex. Since it does not contain a carbonaceous material which is easily soluble in molten pig iron, corrosion resistance is extremely excellent. -9- 200938509 In the case where the refractory raw material complex is composed mainly of alumina and carbonaceous raw materials and aluminum powder, the alumina is used in an amount of 55 to 94% by mass, and the carbonaceous material is used in an amount of 5 to 30% by mass. Since the amount of the carbonaceous raw material used is limited, the reduction in corrosion resistance can be suppressed to some extent. However, since the strength is lowered by the use of the carbonaceous raw material, high strength is not required, and for example, in the use conditions in which the flow of molten iron is small, the effect of being difficult to wet the molten pig iron is excellent and the life is high. Further, in the case where the alumina is less than 55% by mass, the corrosion resistance is low, and if the alumina is more than 94% by mass, the carbonaceous raw material is relatively insufficient, and the effect of the molten pig iron being difficult to wet is insufficient. If the carbonaceous raw material is less than 5 masses, the effect of improving the wettability is insufficient. If the carbonaceous raw material is more than 30% by volume, the thermal conductivity of the refractory is deteriorated due to the dissolution of a part of the carbonaceous raw material into the molten pig iron. It becomes higher and the corrosion resistance is lowered. Although it is preferable that the Si component is not contained in the refractory raw material composition, since Si02 is contained in the aluminum raw material and the carbonaceous raw material, Si is converted to 3 mass% or less, preferably 1% by mass, because of corrosion resistance. It can be used if it has few adverse effects. Here, the Si-based system is an alloy such as an oxide of an alloy or SiO 2 or a non-oxide such as Si3N4 in addition to Si. In the case where SiO 2 is contained in the refractory raw material complex, the SiO 2 is reduced by the carbon in the molten pig iron and dissolved in the Si form as described above, so that the corrosion resistance is lowered. Further, in the case of containing tantalum nitride and tantalum carbide, the Si type is dissolved as described above, or tantalum nitride and tantalum carbide are subjected to gas phase oxidation in a reducing atmosphere to form Si〇2, which is associated with uranium resistance. reduce. For the sake of the original reason, the amount of oxygen in the form of Si is the same as that of -10 - 200938509. Even if a part of the alumina is replaced by titanium dioxide, it is preferable to obtain the brick for the blast furnace hearth. Effect. Titanium dioxide is reduced if contacted with molten pig iron and dissolved in molten pig iron in a Ti form. It is known that dissolved Ti increases the viscosity of molten pig iron, so that the brick forms a protective film near the running surface to improve the durability of the brick. Specifically, titanium dioxide is used in an amount of 1 to 20% by mass in the refractory raw material complex. When the amount is less than 1% by mass, the degree of the effect of the blast furnace hearth is low, and if the amount is more than 20% by mass, the titanium dioxide is dissolved in the molten pig iron, which makes the structure weak and significant. Not good. It is more preferred that the dioxins are used in which the crystalline phase is rutile. The aluminum compound cemented brick of the present invention is formed by adding a binder in the refractory raw material complex as described above and kneading it, and then forming it at a temperature of 1 000 ° C or more, more preferably 1 300 ° in a nitrogen atmosphere or a carbon particle. c above 1 700. (: The following calcination can be obtained. The aluminum compound of the present invention thus obtained is treated, and the structure of the brick is composed of a crystalline phase and an amorphous phase, and the crystalline phase mainly has a quality of 80 to 98% by weight. d, and nitriding crystal and/or carbon oxide crystals are 1 to 18% by mass. 'The amorphous phase is 〇·5 to 1 〇% by mass, and the S i content of the hindrance is 3% by mass or less. The structure of the brick is composed of a crystalline phase and an amorphous phase, the corundum is 55 to 94% by mass, the aluminum nitride crystal and/or the alumina crystal is 1 to 18% by mass, and the graphite is i to 25 mass. % 'Amorphous phase is i~} 〇% by mass, and the Si content in the brick is 3% by mass or less. The amorphous phase here is mainly amorphous carbon contained in the carbonaceous raw material. The so-called ash contained in the carbonaceous raw material, the amorphous oxide (cerium oxide, titanium dioxide, etc.) contained in the alumina -11 - 200938509, etc. are also included. The carbonaceous raw material is composed of a crystalline phase and an amorphous phase. The crystal phase is graphite. Also, a part of the corundum is replaced by rutile. The preferred effect of the brick for the hearth furnace. Specifically, the rutile may contain 1 to 18% by mass relative to the whole structure of the brick. When the content is less than 1% by mass, it is used as a brick for the blast furnace hearth. When the content is more than 18% by mass, the dissolution of rutile in the molten pig iron makes the brittleness φ of the brick structure weak, which is not preferable. Further, Si〇2 is 3% by mass or less, Al2. The alumina brick having a 〇3 of 97% by mass or more can also be used as a brick for a blast furnace hearth. When the content of SiO 2 is 3% by mass or less, the adverse effect of dissolving Si in molten pig iron can be prevented as described above, and Since ai2o3 does not react with molten pig iron, it is a brick for blast furnace hearth which is excellent in corrosion resistance. This alumina brick can be obtained by a common method of calcining in an oxidizing atmosphere by using an alumina raw material having a particle size adjusted. Advantageous Effects of Invention The aluminum compound cemented brick of the present invention is not used Si component or is limited to 3% by mass or less, so that corrosion resistance caused by dissolution of Si in the brick structure into molten pig iron can be suppressed. The aluminum alloy and/or the aluminum carbonate is used as the cemented structure component, so that the protective layer of alumina is formed on the running surface of the brick, and the corrosion resistance is particularly excellent when compared with the prior aluminum-containing compound brick. By using the aluminum compound of the present invention to bond bricks', since the corrosion resistance of the blast furnace bricks is improved, the life of the blast furnace can be prolonged. Further, since the aluminum compound cemented bricks are dense, they can be thinned. The thickness of the lining of the blast furnace is large, and the productivity is also improved. Further, if the aluminum compound cemented brick of the present invention is superior to the previous carbon brick, the above-mentioned reason makes the contact resistance extremely excellent, so it is not necessary. Excessive water cooling to reduce the corrosion resistance of bricks and less energy loss. [Embodiment] The aluminum powder used in the present invention is generally used in the form of a powder used for a refractory, and is preferably used because of its high reactivity. From this point of view, it is more preferable that the aluminum powder has a particle size of 74 μm or less. When alumina is used as the raw material of the refractory material, it can be used without any problem, and fused alumina, sintered oxide, sintered alumina or the like can be used. However, as the content of Si〇2 is less, the corrosion resistance becomes higher. It is preferable to use alumina having a content of Si〇2 of 1% by mass or less, more preferably 0.5% by mass or less. Further, the purity of Al2〇3 is preferably 90% by mass or more, and more preferably 98% by mass or more, from the viewpoint of corrosion resistance to molten pig iron. As the carbonaceous raw material, pseudo-fired smokeless carbon, natural graphite, or artificial graphite can be used. In particular, when the carbonaceous raw material is compared with natural graphite and artificial graphite, it is more difficult to dissolve in the molten pig iron, so that the corrosion resistance is better. Further, since the burnt smokeless carbon has low reactivity with aluminum powder, it also has an advantage that it is difficult to form aluminum carbide. If a large amount of aluminum carbide is produced, -13- 200938509 has the problem of easy hydration of bricks. The main component of the refractory raw material complex of the present invention is composed of aluminum powder and aluminum oxide, or aluminum powder, and alumina and carbonaceous raw materials, but may also be used in an amount of 10% by mass or less of aluminum nitride, Al2OC, A1404C, or oxidation. Hey. However, the Si content in the refractory raw material composition must be 3% by mass or less. Of course, the Si component such as the impurity SiO 2 in the alumina raw material and the carbonaceous raw material is also contained therein. © The refractory raw material mixture is formed by kneading in a normal method, dried as needed, and calcined. In the case of kneading, a commonly used binder is used for the refractory, but the residual carbon ratio of the binder is preferably 10% by mass or less. When the residual carbon ratio of the binder exceeds 10% by mass, the aluminum reacts with the component C in the binder and becomes aluminum carbide, which adversely affects the digestion resistance and the like. The calcination method may be carried out by calcination in a nitrogen stream or in a refractory vessel generally referred to as a muffle furnace, filled with carbon particles for calcination. This muffle can be used by a general user of refractory calcination. In the muffle Ο, a CO gas which reacts with oxygen in the air occurs, and this CO gas reacts with aluminum to estimate the generation of ai2oc and ai4o4c. At this time, a small amount of aluminum nitride is generated or not formed at all. As the carbon particles, coke or carbonaceous bricks which are usually used in a muffle can be used. By the calcination, if one or more of aluminum nitride (A1N) and aluminum carbonate such as Al2〇C and Al4〇4C are formed, a dense and strong cemented structure is formed and a sufficient effect is obtained. The microstructure of the aluminum compound cemented brick of the present invention obtained by the above-mentioned production method is alumina (corundum) or alumina (corundum) and carbonaceous raw material (stone-14 - 200938509 ink) and the cemented structure of the matrix portion is A1N It is composed of one or more of crystal, Al2OC crystal, and AI4O4C crystal. The matrix portion exerts a strong bonding force in a dense continuous sintering phase pattern at the grain boundary of the oxidized crystal grain or the alumina grain and the carbonaceous material. In addition, the content of the Si-containing component such as Si〇2, SiC, and Si3N4 in the brick is 3% by mass or less. When the blast furnace hearth of the present invention is used for the blast furnace, the aluminum compound cemented brick can be used with the previous carbon brick or replaced. Specifically, it can be applied to the side wall or the bottom of the furnace below the pig iron outlet. The side wall or the bottom of the furnace below the tapping hole of the blast furnace is in a state of being in constant contact with the molten pig iron, and it is not necessary to be repaired and used during the period of one year and a half. The brick of the present invention is excellent in corrosion resistance to molten pig iron, so Further extend the life of the blast furnace. [Examples] Table 1, Table 2, and Table 3 show examples and comparative examples of the present invention, and show the test results of the refractory raw material mixture used for the test sample and the test sample obtained therefrom. The liquid phenol resin as a binder was added to the refractory raw material composition of Tables 1, 2 and 3, kneaded, molded, and dried, and then calcined at a predetermined atmosphere of 1 500 °C. The size of the molded body is the same shape as defined in JIS R21 01. With respect to Example 1, Comparative Example 2, and Comparative Example 4 shown in Table 1, and Examples 3 to 7, Comparative Example 5, and Comparative Example 6 shown in Table 2, in a refractory brick muffle furnace made of tantalum carbide. The dried shaped body is placed, embedded in coke granules and calcined under atmospheric atmosphere. Further, each of Examples and Comparative Examples of Example 8 and Comparative Example 1 and Table 2 shown in Table 1 and Tables 1 and 2 shown in Table 1 were supplied in a furnace in a closed electric furnace. Nitrogen gas was calcined in a nitrogen stream while discharging excess gas in the furnace. Comparative Example 3 shown in Table 1 was calcined in the atmosphere. A test piece of 20 mm x 20 mm x 200 mm was cut out from each calcined product, and a molten pig iron immersion test was performed. The molten pig iron immersion test was carried out by inducing the furnace test piece at 1600 ° C in molten pig iron for 5 hours. After cooling, the test piece was cut out and the profile was observed, and the loss characteristics were compared by the size of the test piece. The content of the Si-containing component in the refractory raw material mixture is determined by measuring the chemical composition of the refractory raw material mixture which is uniformly mixed, and converting it into a Si content, which is expressed as a ratio of the refractory raw material complex of 100% by mass. Similarly, the content of the Si-containing component in the calcined brick is also measured and expressed as the ratio of Si in 100% by mass of the brick (for example, in the case where the measurement result is SiO 2 , the amount of Si in the SiO 2 is calculated from the composition ratio, and It is converted into a comparison example of the whole). In Table 1, Example 1 was confirmed by characteristic X-ray analysis to confirm that the cemented structure was Al2OC crystal and A1404C crystal. The size of the remaining portion of the cut surface after the molten pig iron immersion test was 19.5 mm, which was the largest in Table 1, and it was known that the surface was formed into a densified layer of alumina. The ΕΡΜΑ observation photograph of the brick cut surface after the molten pig iron immersion test of this Example 1 is shown in Fig. 1 to Fig. ID. Fig. 1A shows a photograph of a structure, Fig. 1B shows Fe, Fig. 1C shows 0, and Fig. 1D shows ΕΡΜΑ analysis results of A1. A portion with a high density of -16-200938509 was observed near the running surface of Fig. 1C. In this structure, except for Al2〇3, almost no oxide or the like is contained, and almost no oxygen is present in the molten pig iron. Therefore, the enthalpy of the running surface of Fig. 1C is judged to be 0 in Al2〇3. When the Fig. 1D is observed, the portion where the density of Al2〇3 is high is observed on the running surface of the brick. From Fig. 1B, it is understood that the penetration of the pig iron component is small and the durability is excellent. The brick of the first embodiment is in contact with the molten pig iron in the vicinity of the Al2OC and A1404C as the cemented structure and the Al2〇3 running surface of the aggregate, and the Al2〇3 of the aggregate is stable, but the cemented structure is molten iron. It dissolves in the form of AI. When Al2OC and A1404C are in contact with molten pig iron, the latter is dissolved in the molten pig iron in the alumina portion and the aluminum carbide, but the dissolved A1 is formed immediately by the dissolved oxygen in the molten pig iron. That is, if the aluminum compound is in contact with the molten pig iron, it is easily converted into alumina. For these reasons, it is considered that a brick having an aluminum compound as a cemented structure and having alumina as a main component is excellent in uranium resistance to molten pig iron. In Example 2, it was confirmed by X-ray analysis that the cemented structure was composed of A1N junction twins. The test piece after the molten pig iron immersion test was a dense layer having the same residual portion as in Example 1 and forming alumina on the surface. In the second embodiment, the refractory raw material complex contains 15% by mass of sintered smokeless carbon as a carbonaceous raw material, and if it is compared with Example 1 which is completely free of sintered smokeless carbon, the dissolution in the molten pig iron immersion test The amount becomes larger. The reason for this is considered to be that the test piece is rotated in the current molten iron immersion test. Therefore, in Example 2 in which the strength was slightly lowered by using the pseudo-sintered carbon smoke, the surface was worn by the molten iron. In Comparative Example 1, it was confirmed by X-ray analysis that the cemented structure was composed of Sialon -17-200938509, and the ΕΡΜΑ observation photograph of the brick cut surface after the molten pig iron immersion test of Comparative Example 1 is shown in Figs. 2A to 2D. Fig. 2A shows a tissue photograph, Fig. 2A shows Fe, Fig. 2C shows Si, and Fig. 2D shows AΕΡΜΑ analysis result. In Fig. 2C, Si is a structure which disappears from the surface to 1 mm, and a portion in which the pig iron is partially impregnated in Fig. 2B, and it is understood that the substrate or the like is invaded. In the brick of Comparative Example 1, the Si component was contained in a Sialon type, and ❹ was converted into Si in an amount of 8 mass%. It is presumed that Si in the Sialon is slightly dissolved in the molten pig iron in contact with the molten pig iron near the running surface. The dissolved Si is oxidized by the dissolved oxygen in the molten pig iron and becomes SiO 2 again. However, this time is dissolved in the slag in which the CaO floating in the molten pig iron is the main component. Therefore, it is estimated that it adheres to the refractory as in the case of ai2o3. Running surface. For these reasons, it is presumed that the dissolution is progressed in the case of containing Sialon. In Comparative Example 2, it was confirmed by X-ray analysis that the cemented structure was composed of ruthenium carbide G. In the observation of the cut surface after the molten pig iron immersion test, the matrix phase is preferentially lost, and a part of the alumina skeleton flows into the molten pig iron, and the size of the remaining portion is as small as 18 mm. In Comparative Example 3, in the observation of the cut surface after the molten pig iron immersion test, the range of about 1 mm on the surface was approximately completely deteriorated and the original brick structure disappeared. Although the structure remains in the interior, the mold stone of the aggregate is dissolved at the boundary surface. The ΕΡΜΑ observation sheet of the brick cut surface after the molten pig iron immersion test of Comparative Example 3 is shown in Fig. 3A to Fig. 3D. Fig. 3A shows the photograph of the tissue, Fig. 3 shows Fe, Fig. 3C shows Si, and Fig. 3D shows the results of ΕΡΜΑ analysis -18-200938509 showing Α1. In Fig. 3C, 'Si is a surface which disappears from 〇.5 mm' and the structure in which the pig iron is partially impregnated in Fig. 3B is eroded. In the brick of Comparative Example 3, the Si-containing component was contained in the form of SiO 2 in the mold stone and the clay of the raw material, and was converted into Si in an amount of 15% by mass. It is presumed that SiO 2 in the mold and clay is in contact with the molten pig iron in the vicinity of the running surface and is reduced to Si via the carbon in the molten pig iron, and is dissolved in the molten pig iron. The dissolved Si is oxidized by the dissolved oxygen in the molten pig iron and is again changed to Si 〇 2, but this time is the slag which is dissolved in the molten pig iron and floated as CaO. Therefore, it is estimated that it is not attached to the refractory as in the case of ai2o3. The running surface of the object. For these reasons, it is presumed that the dissolution is carried out in the case where si〇2i is contained. As a result of Comparative Examples 1 to 3, it was found that the Si component contained in the blast furnace hearth brick was the cause of the dissolution. In Comparative Example 4, a brick containing carbon as a main component was inferior in corrosion resistance and became high in thermal conductivity. © in Table 2, Example 3 shows that the cemented structure is composed of Al2OC crystals and A1404C crystals by X-ray analysis. A densified layer of alumina was formed on the surface after the molten pig iron immersion test. Since the pseudo-sintered smokeless carbon was contained, the corrosion resistance was slightly inferior to that of Example 1 which was not contained, but it was practically a problem-free range. In Example 4, a part of the alumina of Example 1 of Table 1 was replaced with titanium oxide', but the corrosion resistance to molten pig iron was about the same as that of Example 1. In the examples 5 to 7, in the case of using ruthenium as a raw material, carbon -19-200938509 was formed in the brick, but Si in the refractory raw material composition was 3% by mass or less. ” Good corrosion resistance was exhibited for the molten pig iron. In Comparative Examples 5 and 6, the Si content in the refractory raw material mixture was outside the range of the present invention, and the corrosion resistance to molten pig iron was deteriorated. Example 8 confirmed by X-ray analysis that the cemented structure was composed of A1N crystals. A densified layer of alumina was formed on the surface after the molten pig iron immersion test. φ Table 3 shows an example in which all were calcined under a nitrogen stream and a comparative example, and were calcined under a nitrogen stream to form A1N to become an aluminum nitride bond. In the examples 9 to 11, the amount of Si in the refractory raw material mixture was different, and the smaller the amount, the better the corrosion resistance of the molten pig iron was. In Comparative Examples 7 and 8, the Si content in the refractory raw material mixture was outside the range of the present invention, and when compared with the examples, it was found that the corrosion resistance was greatly deteriorated. The above-mentioned 'aluminum compound cemented brick of the present invention is particularly excellent in corrosion resistance to molten pig iron than the prior refractory material' and is most suitable as a slab for blast furnace hearth. -20- 200938509 o

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Claims (1)

200938509 X. Patent application scope 1. An aluminum compound cemented brick for a blast furnace hearth, characterized in that the main component is composed of alumina and aluminum powder, and contains 85 to 99% by mass of alumina and 1 to 15% by mass. The aluminum powder does not contain a carbonaceous material, and the refractory raw material composition having a Si content of 3% by mass or less is obtained by adding a binder and kneading the mixture, and then calcining it at a temperature of 1 000 ° C or higher in a nitrogen atmosphere or a carbon particle. . Φ 2.—Aluminum compound cemented brick for blast furnace hearth, characterized in that the main component is composed of alumina and carbonaceous raw materials and aluminum powder, containing 55 to 94% by mass of alumina and 5 to 30 mass. % of the carbonaceous raw material and 1 to 15% by mass of the aluminum powder' and the Si content of 3% by mass or less of the refractory raw material complex is added to the binder and kneaded, and then 100 times in a nitrogen atmosphere or carbon particles. (According to calcination above TC. 3. For the aluminum compound cemented brick for blast furnace hearth according to claim 1 or 2, wherein titanium oxide is substituted for one part of alumina in the refractory raw material complex. The blast furnace hearth is made of aluminum compound cemented brick, and the characteristic brick structure is composed of a crystalline phase and an amorphous phase, the crystal phase is 80 to 98% by mass of corundum, and the aluminum nitride crystal and/or the carbon It is 1 to 18% by mass, the amorphous phase is 0.5 to 10% by mass, and the Si content is 3% by mass or less. 5. An aluminum compound cemented brick for a blast furnace hearth, characterized in that the structure of the brick is crystallized. The phase and the amorphous phase are composed, and the crystal phase is corundum of 5 5 ～94. %, Aluminum nitride crystal and / or a carbon-alumina crystal is 1~1 8 mass -26-200938509 The amount % and graphite are 1 to 25% by mass, the amorphous phase is 1 to 10% by mass, and the Si content is 3% by mass or less. 6. For example, the aluminum compound cemented brick for the blast furnace hearth of claim 4 or 5, wherein a part of the corundum is replaced by rutile. -27- 200938509 VII. Designation of Representative Representatives: (1) The representative representative of the case is: None (2), the symbol of the representative figure of this representative figure is simple: None 8. If there is a chemical formula in this case, please reveal the chemical formula that best shows the characteristics of the invention: none ❹ -4-