WO2013151107A1 - Produit réfractaire électrofondu à haute teneur en zircone - Google Patents

Produit réfractaire électrofondu à haute teneur en zircone Download PDF

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WO2013151107A1
WO2013151107A1 PCT/JP2013/060251 JP2013060251W WO2013151107A1 WO 2013151107 A1 WO2013151107 A1 WO 2013151107A1 JP 2013060251 W JP2013060251 W JP 2013060251W WO 2013151107 A1 WO2013151107 A1 WO 2013151107A1
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mass
refractory
zircon
high zirconia
glass
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Japanese (ja)
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戸村　信雄
之浩 牛丸
晋也 林
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旭硝子株式会社
Ａｇｃセラミックス株式会社
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Priority to JP2014509197A priority Critical patent/JP6140687B2/ja
Publication of WO2013151107A1 publication Critical patent/WO2013151107A1/fr

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    • C04B35/01—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics
    • C04B35/48—Shaped ceramic products characterised by their composition; Ceramics compositions; Processing powders of inorganic compounds preparatory to the manufacturing of ceramic products based on oxide ceramics based on zirconium or hafnium oxides, zirconates, zircon or hafnates
    • C04B35/484—Refractories by fusion casting
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    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
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    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3217—Aluminum oxide or oxide forming salts thereof, e.g. bauxite, alpha-alumina
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    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/32—Metal oxides, mixed metal oxides, or oxide-forming salts thereof, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3231—Refractory metal oxides, their mixed metal oxides, or oxide-forming salts thereof
    • C04B2235/3244—Zirconium oxides, zirconates, hafnium oxides, hafnates, or oxide-forming salts thereof
    • C04B2235/3248—Zirconates or hafnates, e.g. zircon
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    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3409—Boron oxide, borates, boric acids, or oxide forming salts thereof, e.g. borax
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
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    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/34—Non-metal oxides, non-metal mixed oxides, or salts thereof that form the non-metal oxides upon heating, e.g. carbonates, nitrates, (oxy)hydroxides, chlorides
    • C04B2235/3418—Silicon oxide, silicic acids, or oxide forming salts thereof, e.g. silica sol, fused silica, silica fume, cristobalite, quartz or flint
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/02—Composition of constituents of the starting material or of secondary phases of the final product
    • C04B2235/30—Constituents and secondary phases not being of a fibrous nature
    • C04B2235/44—Metal salt constituents or additives chosen for the nature of the anions, e.g. hydrides or acetylacetonate
    • C04B2235/447—Phosphates or phosphites, e.g. orthophosphate, hypophosphite
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    • C04B2235/00—Aspects relating to ceramic starting mixtures or sintered ceramic products
    • C04B2235/70—Aspects relating to sintered or melt-casted ceramic products
    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
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    • C04B2235/96—Properties of ceramic products, e.g. mechanical properties such as strength, toughness, wear resistance
    • C04B2235/9669—Resistance against chemicals, e.g. against molten glass or molten salts

Definitions

  • the present invention relates to a high zirconia electrocast refractory, and in particular, when applied to a glass melting furnace, the high zirconia electroforming has excellent durability and reusability and excellent productivity. Regarding refractories.
  • High zirconia electrocast refractories containing 80% by mass or more of ZrO 2 as chemical components have been conventionally used as refractories for glass melting furnaces.
  • High zirconia electrocast refractories are frequently used in contact with molten glass in glass melting furnaces that require high quality such as substrate glass for flat panel displays due to high corrosion resistance and low contamination to molten glass. .
  • the microstructure of the high zirconia electrocast refractory is composed of few pores and a large amount of zirconia (ZrO 2 ) crystal grains and a small amount of matrix glass filled between the grains.
  • This matrix glass is composed of SiO 2 as a main component and other oxides such as Al 2 O 3 , Na 2 O, B 2 O 3 , and P 2 O 5 .
  • High zirconia electrocast refractories change in temperature due to the cooling process during production, when heating up in a glass melting furnace, when cooling down during operation, and during operation and erosion of the refractory itself during operation. Exposed to. Due to these temperature changes, thermal stress and transformation stress generated by a reversible transformation of the zirconia crystal accompanied by a large volume change in a temperature range near 1000 ° C. are generated inside the refractory. If a matrix glass having appropriate thermomechanical properties and amount is contained in the refractory, the refractory becomes flexible with respect to the stress described above and the stress is relieved, and the refractory does not crack. In the following description, the electroformed refractory is also simply referred to as refractory.
  • High zirconia electrocast refractories may produce zircon crystals (ZrO 2 ⁇ SiO 2 ) inside. Since the zircon crystal inside the refractory is formed by the reaction of ZrO 2 and SiO 2 in the matrix glass, the formation of the zircon crystal causes a decrease in the matrix glass in the refractory. The refractory in which zircon crystals are formed and the amount of matrix glass that reduces thermal stress and transformation stress is reduced becomes brittle, and cracks are easily generated even by slight temperature fluctuations.
  • a zircon crystal may be produced by reaction with molten glass. This is either the elution of chemical components that suppress the formation of zircon crystals contained in the refractory into the molten glass, or the penetration of chemical components that promote the formation of zircon crystals into the refractory from the molten glass. One or both occur.
  • the tendency to produce zircon crystals by reaction with molten glass is prominent when the refractory is in contact with low alkali glass or non-alkali glass such as liquid crystal substrate glass.
  • the durability of a refractory is a factor that determines the life of a glass melting furnace. Therefore, the occurrence of cracks in the refractory shortens the life of the glass melting furnace, which is one cause of increasing the glass manufacturing cost.
  • high zirconia electrocast refractories that do not produce zircon crystals while the glass melting furnace is in operation do not crack or, if they do, have fewer cracks than refractories that produce zircon crystals. Because the occurrence of new cracks and the propagation of existing cracks are low when the temperature is lowered when the operation of the glass melting furnace is suspended due to production adjustment, etc., it is relatively easy to reuse.
  • high zirconia electrocast refractories that produced zircon crystals are prominent in the occurrence of new cracks and propagation of existing cracks during this heat reduction, and also when cracks are reheated. Is difficult to reuse. Even if it is reused, high durability is not obtained and the glass melting furnace is short-lived. In other words, high zirconia electrocast refractories that easily generate zircon crystals by reaction with a single substance or molten glass are unsuitable for re-use after operation stoppage, even if they remain in service while the glass melting furnace is in operation. is there.
  • the chemical composition of the refractory is as follows: ZrO 2 is 85 to 97 mass%, SiO 2 is 2 to 10 mass%, Al 2 O 3 is 3 mass% at maximum, and P 2 O 5 is 0.1 to 3 mass%.
  • a high zirconia electroformed refractory material is proposed that is substantially free of mass%, rare earth oxides, and suppresses cracks that occur during production.
  • P 2 O 5 that promotes the formation of zircon crystals is contained, there is a drawback that a zircon crystal is easily generated even with a refractory alone.
  • the chemical composition of the refractory is such that ZrO 2 is 90 to 98 mass%, Al 2 O 3 is 1 mass% or less, and does not contain Li 2 O, Na 2 O, CuO, CaO, or MgO.
  • B 2 O 3 is contained in an amount of 0.5 to 1.5% by mass, or B 2 O 3 is contained in an amount of 0.5 to 1.5% and K 2 O, SrO, BaO, Rb 2 O, Cs
  • One component selected from 2 O is 1.5% or less, or the total of two or more species is 1.5% or less, and a component that suppresses cracking during production and has a large cation radius is used.
  • High zirconia electroformed refractories with high electrical resistance have been proposed. However, there is a defect that B 2 O 3 that promotes the formation of zircon crystals has a high content, and even a refractory alone can easily form zircon crystals.
  • the chemical composition of the refractory is as follows: ZrO 2 is 90 to 95% by mass, SiO 2 is 3.5 to 7% by mass, Al 2 O 3 is 1.2 to 3% by mass, Na 2 O and / or Alternatively, it is assumed that the total content of K 2 O is 0.1 to 0.35% by mass and substantially does not contain any of P 2 O 5 , B 2 O 3, and CuO.
  • Refractories that suppress the formation of crystals have been proposed. However, even in the refractory based on the present invention, the effect of suppressing the formation of zircon crystals was insufficient under the molten glass contact conditions. In addition, there is a problem that cracks are likely to occur during the manufacture of refractories, particularly during the manufacture of large refractories that have an ingot mass of 300 kg or more.
  • the chemical composition is ZrO 2 89 to 96% by mass, SiO 2 3.5 to 7% by mass, Al 2 O 3 0.2 to 1.5% by mass, Na 2 O + K 2 O. 0.05-1.0% by mass, B 2 O 3 less than 1.2% by mass, P 2 O 5 less than 0.5% by mass, B 2 O 3 + P 2 O 5 more than 0.01% by mass Less than 1.7% by mass, CuO less than 0.3% by mass, Fe 2 O 3 + TiO 2 less than 0.3% by mass, BaO from 0.01 to 0.5% by mass, SnO 2 0.3% by mass.
  • the following refractories have been proposed.
  • the chemical composition of the refractory is as follows: ZrO 2 is 87 to 94% by mass, SiO 2 is 3.0 to 8.0% by mass, Al 2 O 3 is 1.2 to 3.0% by mass, Na 2 O exceeds 0.35% by mass and 1.0% by mass or less, B 2 O 3 exceeds 0.02% by mass and less than 0.05% by mass, and substantially does not contain P 2 O 5 or CuO. And the mass ratio of Al 2 O 3 and Na 2 O is 2.5 to 5.0, and the effect of suppressing the formation of zircon crystals in the refractory alone is obtained.
  • the refractory based on this invention optimizes the content ratio of Na 2 O and Al 2 O 3 to suppress the formation of zircon crystals, it contains only a low content of Na 2 O.
  • Preferential elution of Na 2 O occurs under the contact condition with molten glass.
  • the ratio of Na 2 O to Al 2 O 3 quickly deviates from the initial value of the unused state, and the composition of the refractory is a composition that is advantageous for suppressing the formation of zircon crystals within a short period of time. This has the disadvantage that the effect of suppressing the formation of zircon crystals obtained with a single refractory disappears early.
  • the present invention is highly resistant to high zirconia, which does not easily crack in any of refractory production, heating up, temperature change during use and temperature reduction during operation stop, and high durability.
  • the purpose is to provide quality cast refractories.
  • the present inventors have adjusted the matrix glass composition, and in particular, by adjusting the content of K 2 O and Al 2 O 3 to an appropriate range, even a refractory alone can be used under molten glass contact conditions.
  • the present inventors have found a high zirconia electroformed refractory material that is difficult to produce zircon crystals, has a small residual volume expansion even under temperature cycle conditions, and can effectively suppress the occurrence of cracks during refractory production.
  • the high zirconia electrocast refractory of the present invention has a chemical composition of 87 to 96% by mass of ZrO 2 , 2.5 to 9.0% by mass of SiO 2 , and 1.5% by mass of Al 2 O 3. More than 2.5% by mass, 0.15 to 0.6% by mass of Na 2 O, 0.3 to 1.3% by mass of K 2 O, 0 to 0.3% by mass of Li 2 O It is characterized by containing in%.
  • the high zirconia electrocast refractory of the present invention there is no problem of cracking during the production of refractory, and the productivity is excellent, and it is difficult to produce zircon crystals even in the refractory alone or in contact with molten glass. Refractories with high durability and reusability can be obtained because cracks are unlikely to occur during heating, during use, and during heating.
  • the high zirconia electroformed refractory of the present invention is resistant to cracking even under molten glass contact, and has a high durability. By reducing the amount of erosion, contamination of the molten glass can be reduced. Furthermore, since it is difficult for cracks to occur when the glass melting furnace is shut down due to production adjustment or when it is reheated, it is easy to reuse refractories that have little erosion and have not reached the end of their lives. In addition, the high zirconia electrocast refractory of the present invention has no problem of cracking that affects the yield during production, and thus has excellent refractory productivity, and as a result, is advantageous in terms of production cost.
  • the high zirconia electrocast refractory according to the present invention is composed mainly of the five chemical components ZrO 2 , SiO 2 , Al 2 O 3 , Na 2 O and K 2 O described above.
  • the role each of these chemical components plays in the refractory will be described below.
  • the contents of these five components are displayed in an inner line. And about the component which is not described above, it is set as the external display when the sum total of 5 components is 100 mass%.
  • the term “inner” refers to the ratio of each component in 100% by mass, when the total amount of the five components in the high zirconia electroformed refractory is 100% by mass.
  • including 90% by mass of ZrO 2 as an inner part indicates that the total amount of the five components is 100% by mass and that 90% by mass of ZrO 2 is included in 100% by mass.
  • the overhang refers to a ratio based on 100% by mass of the components other than the 5 components when the total amount of the 5 components in the high zirconia electrocast refractory is 100% by mass.
  • including 0.01% by mass of B 2 O 3 on the outside means that the total amount of the five components is 100% by mass, and additionally 0.01% by mass of B 2 O 3 is included.
  • the zirconia raw material and the zircon raw material used for the production of high zirconia electrocast refractories inevitably contain 1 to 3% by mass of HfO 2 , and HfO 2 has almost no loss such as evaporation during production. Therefore, the normal high zirconia electrocast refractory including the present invention contains 1 to 3% by mass of HfO 2 .
  • HfO 2 since the same function as the ZrO 2 in the high-zirconia electrocast refractories generally have a value of ZrO 2 + HfO 2 are merely customary to denoted as ZrO 2, in the present invention ZrO 2 + of HfO 2 The value is expressed as ZrO 2 .
  • the high zirconia electrocast refractory of the present invention is a high zirconia electrocast refractory composed of a large amount of zirconia crystals, a small amount of matrix glass, and a few pores.
  • ZrO 2 which is an inner coating component, has a strong resistance to erosion of molten glass and is contained as a main component of the refractory. Most of this ZrO 2 exists as zirconia crystals having excellent corrosion resistance against molten glass, and only a very small amount is present in the matrix glass.
  • the ZrO 2 content dominates the zirconia crystal content in the high zirconia electroformed refractory of the present invention, and thus affects the corrosion resistance of the refractory to the molten glass.
  • ZrO 2 needs to be 87% by mass or more, and preferably 88% by mass or more.
  • the amount of ZrO 2 exceeds 96% by mass, the amount of matrix glass that acts to relieve stress is relatively small, and cracks are likely to occur due to temperature changes during production, heating, use, and cooling. become. Therefore, ZrO 2 in the high zirconia electroformed refractory of the present invention is 87 to 96% by mass.
  • SiO 2 that is an inner coating component is a main component that forms matrix glass.
  • 2.5 mass% or more of SiO 2 is required.
  • SiO 2 in the high zirconia electrocast refractory of the present invention is 2.5 to 9.0% by mass, preferably 3.0 to 8.5% by mass.
  • Al 2 O 3 which is an inner coating component, is a component that lowers the viscosity of the matrix glass and at the same time suppresses the formation of zircon crystals to some extent. Even under low alkali glass and non-alkali glass contact conditions where the formation of zircon crystals becomes significant, many of these glasses have a relatively high content of Al 2 O 3 , and the concentration generated between the refractory and the molten glass The gradient difference is small and the dissolution of Al 2 O 3 from the refractory is slow. Therefore, the effect of suppressing the formation of zircon crystals by Al 2 O 3 can be enjoyed over a long period of time.
  • the solubility during refractory production becomes good, and the effect of reducing the time and power required for dissolution during refractory production is obtained.
  • the molten metal flow at the time of casting is improved and the molten metal flows into every corner of the mold, the occurrence of defects due to the molten metal not reaching the corners of the mold is suppressed.
  • the good hot water flow facilitates the production of refractories when using a relatively thin mold having a thickness of, for example, 100 mm or less. That is, when Al 2 O 3 is contained at an appropriate content, the productivity of the cast refractory can be improved.
  • Al 2 O 3 in the high zirconia electroformed refractory of the present invention is more than 1.5 mass% and not more than 2.5 mass%, preferably 1.6 to 2.5 mass%, preferably 1 .8 to 2.3% by mass.
  • Na 2 O which is an inner coating component, is a component that effectively suppresses the occurrence of cracks during the production of electrocast refractories.
  • Na 2 O is a component having an effect of suppressing the formation of zircon crystals in the thermal history of the refractory alone.
  • Na 2 O does not have the effect of suppressing the formation of zircon crystals as much as K 2 O or Cs 2 O.
  • Na 2 O, as well as Al 2 O 3 and K 2 O is a component that lowers the viscosity of the matrix glass, but its viscosity-reducing effect is particularly remarkable and effective in suppressing the formation of zircon crystals under molten glass contact conditions.
  • Al 2 O 3 and K 2 O is a component, and accelerate the dissolution of Cs 2 O to the molten glass, and there is a possibility to increase the penetration of the molten glass components produced promotion of B 2 O 3, etc. zircon Therefore, it cannot be contained in a large amount.
  • Na 2 O the low content of preferably Na 2 O content of the high-zirconia electrocast refractories of the present invention is 0.15 to 0.6 mass%, preferably 0.17 It is ⁇ 0.58 mass%, more preferably 0.20 to 0.55 mass%.
  • K 2 O which is an inner coating component, is also a component that reduces the viscosity of the matrix glass and at the same time suppresses the formation of zircon crystals.
  • K 2 O has the role of lowering the viscosity of the matrix glass. If K 2 O is included in the refractory, the temperature is lowered during production, during heating, during use, or during use. The action which suppresses the crack of the refractory by the temperature change at the time is acquired. In addition, since the cation radius of K is large, elution is slow even when it comes into contact with molten glass, and the effect of suppressing the formation of zircon crystals is given over a long period of time.
  • K 2 O Insufficient K 2 O produces aluminosilicate crystals such as mullite during manufacturing and use, resulting in a decrease in the amount of matrix glass, and temperature changes during manufacturing, heating, use, and temperature reduction Cracks are likely to occur.
  • K 2 O is present in an amount of 1.3% by mass or more, particularly exceeding 1.3% by mass, potassium-containing aluminosilicate crystals such as leucite are produced during production or heating by use, This results in a decrease in the amount of matrix glass, and cracks are likely to occur due to temperature changes during manufacturing, heating, use, and heating.
  • K 2 O in the high zirconia electroformed refractory of the present invention is 0.3 to 1.3% by mass, preferably 0.4 to 1.2% by mass, and more preferably 0.5 to 1.1% by mass.
  • the content of Na 2 O and K 2 O in the refractories it is preferable to prepare the ratio of K 2 O with respect to Na 2 O of (K 2 O / Na 2 O ) in a predetermined relationship.
  • the numerical value of K 2 O / Na 2 O is preferably 0.5 to 8, more preferably 0.8 to 7, and further preferably 1.1 to 6.
  • K 2 O can stably suppress the formation of zircon crystals even under the contact conditions with the molten glass as described above.
  • the present inventors have newly found that cracks are likely to occur during the production of electroformed refractories under conditions that contain a large amount of K 2 O and Al 2 O 3 and no Na 2 O. did.
  • the total amount of Na 2 O and K 2 O is preferably 0.5 to 1.6% by mass, more preferably 0.55 to 1.4% by mass. More preferably, it is 0.6 to 1.2% by mass. If the total amount of Na 2 O and K 2 O (Na 2 O + K 2 O) is insufficient, cracks are likely to occur during the production of the refractory, and the formation of zircon crystals in the refractory alone is difficult to suppress. The solubility at the time of manufacturing the product is not good, and the effect of reducing the time and power required for the melting at the time of manufacturing the refractory cannot be obtained.
  • Li 2 O can be contained as an outer coating.
  • Li 2 O is not involved in the suppression of the formation of zircon crystals, it has the effect of promoting the melting of other raw materials, so the productivity when manufacturing a refractory is improved.
  • the content of Li 2 O exceeds 0.3% by mass, the refractory may be cracked during refractory production.
  • the content of Li 2 O is preferably 0.15% by mass or less, more preferably 0.1% by mass or less, and still more preferably substantially free of unavoidable impurities. When Li 2 O is contained, 0.03% by mass or more is preferable, and 0.05% by mass or more is more preferable.
  • B 2 O 3 which is an outer coating component, is a component that promotes the formation of zircon crystals.
  • B 2 O 3 which is an outer coating component, is a component that promotes the formation of zircon crystals.
  • the refractory produces a zircon crystal only with a thermal history, and even a small amount may promote the formation of the zircon crystal under molten glass contact conditions. Therefore, a low content of B 2 O 3 is preferable in terms of suppressing the formation of zircon crystals.
  • B 2 O 3 is allowed up to 0.25% by mass, preferably Is 0.15 mass% or less.
  • B 2 O 3 is more preferably 0.08% by mass or less.
  • B 2 O 3 has the effect of suppressing cracking during refractory production even at a low content, so B 2 O 3 is included in the refractory within a range that is not inconvenient for suppressing the formation of zircon crystals.
  • precise composition control can be performed to maintain high refractory productivity.
  • P 2 O 5 which is an outer coating component, is a component that promotes the formation of zircon crystals in the same manner as B 2 O 3 .
  • the refractory produces a zircon crystal only with a thermal history, and even a small amount may promote the formation of a zircon crystal under molten glass contact conditions. Therefore, P 2 O 5 is preferably as low as possible in terms of suppressing the formation of zircon crystals.
  • P 2 O 5 has an effect of suppressing cracking during refractory production even at a low content, and is also a component that is inevitably mixed depending on the type of zirconia raw material or zircon raw material. If the inclusion of P 2 O 5 is unacceptable at all, it is necessary to use an expensive refining raw material or a relatively expensive zircon raw material or zirconia raw material with a limited production area.
  • P 2 O 5 is up to 0.25% by mass as an outer shell. Acceptable, preferably 0.15% by weight or less.
  • P 2 O 5 is more preferably 0.08% by mass or less. Therefore, the selection range of the zircon raw material and the zirconia raw material is not narrowed, and a relatively inexpensive raw material cost can be achieved. Furthermore, as in the case of B 2 O 3 , if P 2 O 5 is included in the refractory within a range that does not cause inconvenience in suppressing the formation of zircon crystals, and precise composition control is performed, the productivity of the refractory increases. I can keep it.
  • both B 2 O 3 and P 2 O 5 are components that promote the formation of zircon crystals and have a sufficient effect of suppressing the formation of zircon crystals in the refractory against these components.
  • the total amount of B 2 O 3 and P 2 O 5 is preferably 0.4% by mass or less, more preferably 0.3% by mass or less, Especially preferably, it is 0.1 mass% or less. Considering the suppression of the formation of zircon crystals, 0.05% by mass or less is preferable, and it is more preferable not to contain substantially except for inevitable impurities.
  • Cs 2 O which is an outer coating component may be included.
  • Cs 2 O is also a component that suppresses the formation of zircon crystals, and the effect is exhibited even at a low content.
  • the cation radius of Cs is very large, even if it contacts with molten glass, the elution from a refractory material is very slow, and the effect of suppressing the formation of zircon crystals is given particularly for a long period of time.
  • the content of Cs 2 O is 0.05 to 3.8% by mass as an outer coating, Furthermore, it is preferably 0.05 to 3.5% by mass, more preferably 0.05 to 2.5% by mass, and particularly preferably 0.05 to 0.7% by mass.
  • Fe 2 O 3 and TiO 2 contained as impurities in the raw material are components that cause coloring and foaming of the molten glass, and it is not preferable to have a high content.
  • the total amount of these Fe 2 O 3 and TiO 2 is an amount that does not exceed 0.2% by mass, and there is no problem of coloring when the outer coating is 0.3% by mass or less.
  • the raw materials contain Y 2 O 3 and CaO as impurities, but these tend to increase the residual volume expansion coefficient in the thermal cycle test, and the total amount of these Y 2 O 3 and CaO is When the outer coating is 0.3% by mass or less, there is no problem, and the amount is preferably not more than 0.2% by mass.
  • BaO which is an outer coating component
  • BaO is an alkaline earth metal oxide component having a property of reducing the viscosity of the matrix glass.
  • BaO is not an essential component, and its inclusion at a low concentration does not deteriorate the properties of the refractory. Therefore, there is no problem in including it in the refractory at a low concentration.
  • BaO when BaO is contained in the refractory at a high concentration, the viscosity of the matrix glass is greatly reduced, and thus there is a tendency to promote the occurrence of cracks in the refractory during production. Therefore, when BaO is contained, it is preferably 0 to 1% by mass as an outer shell.
  • raw materials such as alumina, zircon sand, silica, potassium carbonate, cesium carbonate, B 2 O 3 and P 2 O 5 are mixed and mixed with desiliconized zircon which is a zirconia raw material.
  • This raw material was charged into a three-phase arc electric furnace with an output of 1500 kVA equipped with three graphite electrodes and completely melted by energization heating.
  • the molten metal was cast by pouring 500 to 600 kg into a graphite mold previously buried in silica sand as a slow cooling material, and allowed to cool to a temperature near room temperature.
  • This graphite mold was manufactured so as to obtain a material for a refractory product having a thickness of 250 mm, a width of 310 mm, and a height of 820 mm and containing no shrinkage nest.
  • the mold was designed and manufactured so as to be an ingot in which a hot metal portion having the same volume as the material portion of the refractory product was provided above the portion used for the material of the refractory product.
  • the ingot and the graphite mold were extracted from the slow cooling material, and the graphite mold and the ingot were separated to produce a high zirconia electroformed refractory.
  • the raw material composition was adjusted to obtain high zirconia electroformed refractories having the chemical compositions shown in Tables 1 to 5.
  • Tables 1, 2 and 4 show Examples (Examples 1 to 15 and Examples 23 to 25), and Tables 3 and 5 show Comparative Examples (Examples 16 to 22 and Examples 26 to 28). )showed that.
  • ZrO 2 , SiO 2 , and Al 2 O 3 are quantitative analysis values determined by wavelength dispersive X-ray fluorescence analysis, and other components are high frequency inductively coupled plasma emission spectroscopy. Quantitative analysis value determined by However, the quantification of each component is not limited to this analysis method, and other quantitative analysis methods may be used.
  • the crack on the appearance of the ingot was evaluated as follows. First, a hot metal portion was cut out from an ingot of a high zirconia electrocast refractory to produce a refractory product material having a thickness of 250 mm ⁇ width of 310 mm ⁇ height of 820 mm. Subsequently, the length of the crack which can be confirmed with the naked eye in the raw material was measured with calipers.
  • the crack length in the material of the refractory product is preferably less than 100 mm, more preferably 70 mm or less, still more preferably 50 mm or less, and most preferably less than 30 mm.
  • the high zirconia electroformed refractory In this thermal cycle test, the high zirconia electroformed refractory generally exhibits residual volume expansion and, in some cases, cracks.
  • This residual volume expansion is obtained by testing the refractory alone against a thermal cycle in a relatively low temperature region, and when the refractory is applied to a glass melting furnace, it is near the outer surface of the furnace that is relatively low temperature away from the molten glass. It shows crack resistance.
  • the residual volume expansion rate by this test is preferably less than 3% by volume, and more preferably less than 2% by volume.
  • zircon crystal formation rate in thermal cycle test In addition, some refractories produce zircon crystals in this thermal cycle test. About the electrocast refractory which passed the said heat cycle test, the production
  • the zircon crystal production rate under the contact condition with molten glass was determined by the following immersion test. That is, a 15 mm ⁇ 25 mm ⁇ 30 mm sample was cut out from the obtained electroformed refractory, and this was inserted into a 200 cc platinum crucible together with 250 g of an alkali-free glass cullet, and a predetermined temperature and a predetermined time in an electric furnace. Heated. After cooling, the sample was taken out and crushed.
  • the X-ray diffraction measurement is performed on the pulverized sample powder, the peak area ratio of the zircon crystal and zirconia crystal is obtained from the diffraction pattern, and the mass% is determined by the ratio of zircon crystal amount / (zircon crystal amount + zirconia crystal amount), This was defined as the zircon crystal production rate in the immersion test.
  • the glass used in this test has a chemical composition of SiO 2 60 mass%, B 2 O 3 8 mass%, Al 2 O 3 17 mass%, MgO 3 mass%, CaO 4 mass%, SrO. Is an alkali-free glass.
  • the test conditions in the immersion test were as follows. As immersion test 1, a test was conducted at 1250 ° C. for 20 days. At this time, heating from room temperature to 1250 ° C. is performed at 300 ° C. per hour, and after holding at 1250 ° C., the temperature is maintained for 20 days, then cooled to 700 ° C. per hour at 500 ° C., and further cooled from 700 ° C. to room temperature per hour Did.
  • the zircon crystal production rate is preferably 4% by mass or less, and more preferably 2% by mass or less.
  • the immersion test 2 As the immersion test 2, a test was conducted at 1450 ° C. for 4 days. At this time, heating from room temperature to 1450 ° C. is performed at 300 ° C. per hour. After reaching 1450 ° C., the temperature is maintained for 4 days, then cooled to 700 ° C. at 500 ° C. per hour, and further cooled from 700 ° C. to room temperature at 60 ° C. per hour. Did. In this test, the zircon crystal production rate is preferably 4% by mass or less, and more preferably 2% by mass or less.
  • the high zirconia electrocast refractory according to the present invention has a crack sufficiently controlled to be less than 30 mm during production, or is 70 mm or less even if there is a crack. It was. Therefore, the high zirconia electrocast refractory of the present invention can be easily manufactured with high productivity.
  • Examples 2, 4 to 6, 15, 24 are components that suppress the formation of zircon crystals, that is, Al 2 O 3 , K 2 O, Cs 2 O, and components that promote the formation of zircon crystals, that is, As a result of the balance between the contents of B 2 O 3 and P 2 O 5 , the composition was such that only a small amount of zircon crystals was produced, and thus some zircon crystals were produced, but the crystal production rate was 1.2% by mass. It is the following and it is the range which can fully suppress generation
  • Example 1 The zircon crystal production rate in the immersion test 1 of the electrocast refractories of 1 to 15 and 23 to 25 is 1.8% by mass or less. Furthermore, the zircon crystal production rate in the immersion test 2 of the electrocast refractories of Examples 1 to 15 and 23 to 25 is also 2.0% by mass or less.
  • the refractories of Examples 1 to 15 and 23 to 25 have a very low zircon crystal production rate of 2.0% by mass or less, and the high zirconia electrocast refractory of the present invention is It can be said that it is difficult to produce zircon crystals even under glass contact conditions.
  • the high zirconia electrocast refractory of the present invention has no problem of cracking during production, the residual volume expansion coefficient due to the thermal cycle of the refractory alone is low, it is difficult to produce zircon crystals, and the molten glass contact conditions Is also a highly durable refractory that is excellent in productivity, temperature change during use, and reusability.
  • the residual volume expansion coefficient in the thermal cycle test is 3% by volume or more. In other words, this refractory has insufficient crack resistance against temperature changes in the refractory alone.
  • 4% by mass or more of zircon crystals were detected from the samples after the thermal cycle test. That is, these refractories easily generate zircon crystals with the refractory alone.
  • the refractories of Examples 16, 17, 22, 27, and 28 all have a zircon crystal production rate of 5% by mass or more in the immersion test 1 and the immersion test 2. That is, these refractories tend to form zircon crystals under glass contact conditions.
  • the high zirconia electrocast refractory of the present invention is excellent in productivity, hardly cracks when heated up, hardly forms a zircon crystal even when subjected to a heat history alone, and melts. It can be seen that it is difficult to form zircon crystals even when in contact with glass. Therefore, it is a highly zirconia electroformed refractory material that is resistant to cracking even during temperature changes during use and heat reduction during operation suspension, has high durability, and is excellent in reusability. Suitable for melting furnace of alkali glass and non-alkali glass.
  • the high zirconia electrocast refractory of the present invention is excellent in productivity, has high durability and good reusability, extends the life of the glass melting furnace, reduces glass defects, and operates the glass melting furnace Since it is easy to stop and restart, it is particularly suitable as a refractory for a glass melting furnace. It should be noted that the entire contents of the specification, claims, and abstract of Japanese Patent Application No. 2012-087309 filed on April 6, 2012 are hereby incorporated herein by reference.

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  • Engineering & Computer Science (AREA)
  • Ceramic Engineering (AREA)
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  • Composite Materials (AREA)
  • Manufacturing & Machinery (AREA)
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  • Structural Engineering (AREA)
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Abstract

L'invention fournit un produit réfractaire électrofondu à haute teneur en zircone présentant une haute durabilité, et dans lequel des fissures sont peu susceptibles de se produire, lors d'une baisse de température soit pendant la fabrication du produit réfractaire, soit pendant l'élévation de la température soit pendant un changement de température lors de sa mise en œuvre ou une mise à l'arrêt. Plus précisément, l'invention concerne un produit réfractaire électrofondu à haute teneur en zircone qui est caractéristique en ce qu'il comprend en tant que composition chimique 87 à 96% en masse de ZrO2, 2,5 à 9,0% en masse de SiO2, plus de 1,5% en masse à 2,5% en masse au maximum de Al2O3, 0,15 à 0,6% en masse de Na2O, 0,3 à 1,3% en masse de K2O, et 0 à 0,3% en masse en pourcentage externe de Li2O.
PCT/JP2013/060251 2012-04-06 2013-04-03 Produit réfractaire électrofondu à haute teneur en zircone WO2013151107A1 (fr)

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Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2835364A4 (fr) * 2012-04-06 2015-11-18 Asahi Glass Co Ltd Produit réfractaire électrofondu à haute teneur en zircone
EP2956428A4 (fr) * 2013-08-21 2016-11-30 Saint Gobain Tm K K Produit réfractaire électrofondu à haute teneur en zircone
US10407349B2 (en) 2015-04-24 2019-09-10 Corning Incorporated Bonded zirconia refractories and methods for making the same
CN116472257A (zh) * 2020-11-24 2023-07-21 圣戈班Tm股份有限公司 高氧化锆电熔铸耐火物

Families Citing this family (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP3453689B1 (fr) * 2017-09-08 2020-08-26 AGC Ceramics Co., Ltd. Réfractaire électrofondu à forte teneur en zircone et son procédé de fabrication

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JPS6259576A (ja) * 1985-09-10 1987-03-16 旭硝子株式会社 高ジルコニア質熱溶融耐火物
JPH08277162A (ja) * 1995-04-06 1996-10-22 Toshiba Monofrax Co Ltd 高ジルコニア溶融耐火物
WO2010116960A1 (fr) * 2009-04-06 2010-10-14 旭硝子株式会社 Matériau réfractaire à forte base de zircone et four de fusion
WO2012046785A1 (fr) * 2010-10-06 2012-04-12 旭硝子株式会社 Produit réfractaire à teneur élevée de zircone
WO2012046786A1 (fr) * 2010-10-06 2012-04-12 旭硝子株式会社 Produit réfractaire à teneur élevée de zircone

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JP3411057B2 (ja) * 1992-06-26 2003-05-26 旭硝子セラミックス株式会社 高ジルコニア質溶融鋳造耐火物

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JPS6259576A (ja) * 1985-09-10 1987-03-16 旭硝子株式会社 高ジルコニア質熱溶融耐火物
JPH08277162A (ja) * 1995-04-06 1996-10-22 Toshiba Monofrax Co Ltd 高ジルコニア溶融耐火物
WO2010116960A1 (fr) * 2009-04-06 2010-10-14 旭硝子株式会社 Matériau réfractaire à forte base de zircone et four de fusion
WO2012046785A1 (fr) * 2010-10-06 2012-04-12 旭硝子株式会社 Produit réfractaire à teneur élevée de zircone
WO2012046786A1 (fr) * 2010-10-06 2012-04-12 旭硝子株式会社 Produit réfractaire à teneur élevée de zircone

Cited By (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP2835364A4 (fr) * 2012-04-06 2015-11-18 Asahi Glass Co Ltd Produit réfractaire électrofondu à haute teneur en zircone
EP2956428A4 (fr) * 2013-08-21 2016-11-30 Saint Gobain Tm K K Produit réfractaire électrofondu à haute teneur en zircone
US10407349B2 (en) 2015-04-24 2019-09-10 Corning Incorporated Bonded zirconia refractories and methods for making the same
CN116472257A (zh) * 2020-11-24 2023-07-21 圣戈班Tm股份有限公司 高氧化锆电熔铸耐火物
CN116472257B (zh) * 2020-11-24 2024-06-04 圣戈班Tm股份有限公司 高氧化锆电熔铸耐火物

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